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  • 1.
    Nilsson, Sara
    et al.
    Linköping University, Department of Management and Engineering, Manufacturing Engineering. Linköping University, Faculty of Science & Engineering.
    Jensen, Jonas
    Linköping University.
    Björkman, Mats
    Linköping University, Department of Management and Engineering, Manufacturing Engineering. Linköping University, Faculty of Science & Engineering.
    Sundin, Erik
    Linköping University, Department of Management and Engineering, Manufacturing Engineering. Linköping University, Faculty of Science & Engineering.
    11 Rules of Design for Manufacturing when Producing Pre-Impregnated Carbon Fiber-Reinforced Plastic Components: an Application at SAAB Aerostructures2016In: SAE Technical Papers, Society of Automotive Engineers, 2016, 1-8 p., 2016-01-2124Conference paper (Refereed)
    Abstract [en]

    Carbon ber-reinforced plastic (CFRP) is one of the most commonly used materials in the aerospace industry today. CFRP in pre- impregnated form is an anisotropic material whose properties can be controlled to a high level by the designer. Sometimes, these properties make the material hard to predict with regards to how the geometry affects manufacturing aspects. This paper describes eleven design rules originating from different guidelines that describe geometrical design choices and deals with manufacturability problems that are connected to them, why they are connected and how they can be minimized or avoided. Examples of design choices dealt with in the rules include double curvature shapes, assembly of uncured CFRP components and access for non-destructive testing (NDT). To verify the technical content and ensure practicability, the rules were developed by, inter alia, studying literature and performing case studies at SAAB Aerostructures. The research was done through a collaboration between Linköping University and SAAB Aerostructures in a state-funded project. This ensured a balanced approach between academic advancement and usefulness in commercial projects. 

  • 2.
    Halling, Jon
    Linköping University, Department of Electrical Engineering.
    1553-Simulator. In-/uppspelning av databusstrafik med hjälp av FPGA2002Independent thesis Basic level (professional degree)Student thesis
    Abstract [en]

    At Saab Aerospace in Linköping, components for measurement systems to the fighter aircraft JAS 39 Gripen are developed. In this activity you sometimes want to record the traffic transmitted on the data busses that connects different sys-tems. This traffic on the data busses is using the military standard MIL-STD-1553.

    This project has aimed to create a system for recording and sending 1553-data. The system is used on an ordinary personal computer, equipped with a recon- figurable I/O card that among others has a programmable logic circuit (FPGA). The recorded data are stored on a hard drive. The system has a graphical user interface, where the user can configure different methods of filtering the data, and other preferences.

    The completed system has currently the capacity to record one channel. This works excellent and the system basically meets all the requirements stated at the start of the project. By using this system instead of the commercial available systems on the market one will get a competitive alternative. If the system where to be developed further, with more channels, it would get even more price worth. Both in case of price per channel, but also in functionality. This is because it is possible to design exactly the functions the user demands. But the current version is already fully functional and competitive compared to commercial systems.

  • 3.
    Turner, Anthony
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics.
    24th Anniversary World Congress on Biosensors – Biosensors 20142014Conference proceedings (editor) (Refereed)
    Abstract [en]

    Welcome to Biosensors 2014 and welcome to Melbourne, ranked as the world's most liveable city!

    This is the 24th anniversary edition of the World Congress on Biosensors and we continue to evolve, adapt and grow into new roles to serve the analytical needs of a rapidly changing society. Advances in telecommunications, expert systems and distributed diagnostics are prompting us to question the conventional ways we deliver healthcare, while robust industrial sensors are facilitating new paradigms in R&D and production. Personalisation of everything from medicine to environmental control, is giving new impetus to consumer choice and ownership of information, and will inevitably generate new payment structures and business models. Moreover, a deeper understanding of the bio/electronic interface leads us towards new horizons in areas such as bionics, power generation and computing.  Wearable, mobile and integrated sensors are becoming common place, but most current products have taken the easy path of incorporating physical sensors for parameters such as temperature, pressure, orientation or position. There is still a glaring absence of suitably robust and convenient commercial biosensors for body chemistries and ecosystems, and therein lies the real opportunities for progress.  We are a still-emerging technology that is fuelling scientific discovery and underpinning new products to enhance the length and quality of life.

    Always in a new country and always with fresh plenary speakers, we aim to reflect the latest and the best in Biosensors. This three-day event, organised by Elsevier in association with Biosensors & Bioelectronics, consists of two daily plenary presentations from leading figures in the field, followed by four parallel sessions, comprising a rigorously refereed selection of submitted papers. This year, we received 1,156 submissions of which 124 with be presented as regular Oral papers, with an additional 20 singled out as Invited talks and a further 12 selected for extended Keynote talks. The Keynote speakers have also been invited to submit full papers for consideration for the Biosensors and Bioelectronics Prize for the most original contribution to the Congress and the winners will be announced at the conference banquet on Thursday night. There will also be poster awards and you will find voting slips for each of the three days in your delegate bags. The winners of these awards and a prize draw, sponsored by Linköping University and Acreo Swedish ICT, will be announced at the closing ceremony on Friday. In order to enhance the valued medium of poster presentation, this year we have introduced a new Poster in my Pocket Ap.  Poster presenters have been able to upload a PDF of their poster prior to the conference to help increase the exposure of their work. This compliments the other new Ap introduced this year to place the full programme at your fingertips. Selected oral presentations will also have the opportunity to upload their talks online for future viewing.

    The academic programme, as usual, is enhanced by a fine collection of commercial exhibits and in addition to browsing their stands; you will be able to hear short elevator pitches during the breaks. We must thank our main commercial sponsor, Ercon for their generous and continued support of our congress. Thanks also to New Tools for Health for sponsoring the pre-congress Networking Event.  Now a regular feature for Biosensors, we have a pre-congress school, this year on Optical Biosensors, which is brought to you by Profs Fran Ligler and Tanya Monro. Last, but not least I must thank our marvellous Local Organising Committee chaired by Prof Justin Gooding, our hard working main Organising Committee, all the speakers and delegates, and the Elsevier team for all their support.

    Our delegates come from the four corners of the globe to hear the science, to grasp the opportunities and to meet the people; it’s going to be the best meeting yet. Enjoy and don’t forget to join us again in Gothenburg, Sweden, 24-27 May for Biosensor 2016!

  • 4.
    Grundström, Hanna
    et al.
    Region Östergötland, Center of Paediatrics and Gynaecology and Obstetrics, Department of Gynaecology and Obstetrics in Norrköping. Linköping University, Department of Medical and Health Sciences. Linköping University, Faculty of Medicine and Health Sciences.
    Kjølhede, Preben
    Region Östergötland, Center of Paediatrics and Gynaecology and Obstetrics, Department of Gynaecology and Obstetrics in Linköping. Linköping University, Department of Clinical and Experimental Medicine, Division of Clinical Sciences. Linköping University, Faculty of Medicine and Health Sciences.
    Berterö, Carina
    Linköping University, Department of Medical and Health Sciences, Division of Nursing Science. Linköping University, Faculty of Medicine and Health Sciences.
    Alehagen, Siw
    Linköping University, Department of Medical and Health Sciences, Division of Nursing Science. Linköping University, Faculty of Medicine and Health Sciences.
    “A challenge” – healthcare professionals' experiences when meeting women with symptoms that might indicate endometriosis2016In: Sexual & Reproductive HealthCare, ISSN 1877-5756, E-ISSN 1877-5764, Vol. 7, 65-69 p.Article in journal (Refereed)
    Abstract [en]

    Objective

    The aim of the study was to identify and describe the experiences of healthcare professionals when meeting women with symptoms that might indicate endometriosis.

    Methods

    Semi-structured interviews were conducted with 10 gynecologists, six general practitioners and nine midwives working at one university hospital, one central hospital, one private gynecology clinic and five healthcare centers in south-east Sweden. The interviews were recorded and transcribed verbatim and analyzed using qualitative conventional content analysis.

    Results

    Three clusters were identified: the corroborating encounter, the normal variation of menstruation cycles, and the suspicion of endometriosis. The healthcare professionals tried to make a corroborating encounter by acknowledging the woman, taking time to listen, and giving an explanation for the problems. Healthcare professionals had different ways to determine what was normal as regards menstrual pain, ovulation pain and dyspareunia. They also needed to have the competence to act and react when the symptoms indicated endometriosis.

    Conclusions

    Meeting women with symptoms that might indicate endometriosis is challenging and demands a certain level of competence from healthcare professionals. Sometimes the symptoms are camouflaged as “normal” menstruation pain, making it hard to satisfy the needs of this patient group.

  • 5.
    Safavi, Edris
    et al.
    Linköping University, Department of Management and Engineering, Machine Design. Linköping University, The Institute of Technology.
    Gopinath, Varun
    Linköping University, Department of Management and Engineering, Machine Design. Linköping University, The Institute of Technology.
    Ölvander, Johan
    Linköping University, Department of Management and Engineering, Machine Design. Linköping University, The Institute of Technology.
    Gavel, Hampus
    SAAB AB, Sweden.
    A Collaborative Tool for Conceptual Aircraft Systems Design2012In: Guidance, Navigation, and Control and Co-located Conferences: AIAA Modeling and Simulation Technologies Conference / [ed] The American Institute of Aeronautics and Astronautics, Reston, VA, USA: American Institute of Aeronautics and Astronautics, 2012, 1-10 p.Conference paper (Refereed)
    Abstract [en]

    Advances in recent years has brought forth many feasible technologies which oer signif-icant design advantages over the traditional aircraft vehicle ight systems. These advanceshave brought about a need for the aircraft conceptual engineers to evaluate these newtechnologies so as to realize a realistic and optimized architecture which fulls all criti-cal disciplinary requirements. To evaluate these systems, it is necessary to use models ofcomplexity which are a degree higher than what is being used today. Quick developmentand evaluation of these models can be a hard task for an engineer to achieve consideringthe multidisciplinary nature of the systems. A collaborative eort in model developmentbetween various department is needed if the conceptual design is to be completed withinthe time frame. To facilitate a collaborative conceptual design a research project was for-malized at Linkoping university, which has led to the development of a tool named CAVE(Conceptual Aircraft Vehicle Engineering) which can be used to evaluate the architectureof aircraft systems. In this paper, CAVE as a conceptual design tool will be presented.

  • 6.
    Lagerqvist, Victor
    Linköping University, Department of Computer and Information Science, TCSLAB - Theoretical Computer Science Laboratory.
    A comparison of SL- and unit-resolution search rules for stratified logic programs2010Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    There are two symmetrical resolution rules applicable to logic programs - SL-resolution which yields a top-down refutation and unit-resolution which yields a bottom-up refutation. Both resolution principles need to be coupled with a search rule before they can be used in practice. The search rule determines in which order program clauses are used in the refutation and affects both performance, completeness and quality of solutions. The thesis surveys exhaustive and heuristic search rules for SL-resolution and transformation techniques for (general) logic programs that makes unit-resolution goal oriented.

    The search rules were implemented as meta-interpreters for Prolog and were benchmarked on a suite of programs incorporating both deterministic and nondeterministic code. Whenever deemed applicable benchmark programs were permuted with respect to clause and goal ordering to see if it affected the interpreters performance and termination.

    With the help of the evaluation the conclusion was that alternative search rules for SL-resolution should not be used for performance gains but can in some cases greatly improve the quality of solutions, e.g. in planning or other applications where the quality of an answer correlates with the length of the refutation. It was also established that A* is more flexible than exhaustive search rules since its behavior can be fine-tuned with weighting, and can in some cases be more efficient than both iterative deepening and breadth-first search. The bottom-up interpreter based on unit-resolution and magic transformation had several advantages over the top-down interpreters. Notably for programs where subgoals are recomputed many times. The great disparity in implementation techniques made direct performance comparisons hard however, and it is not clear if even an optimized bottom-up interpreter is competitive against a top-down interpreter with tabling of answers.

  • 7.
    Bäckström, Christer
    et al.
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, Faculty of Science & Engineering.
    Jonsson, Peter
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, Faculty of Science & Engineering.
    Ordyniak, Sebastian
    Masaryk University, Czech Republic.
    Szeider, Stefan
    Vienna University of Technology, Austria.
    A complete parameterized complexity analysis of bounded planning2015In: Journal of computer and system sciences (Print), ISSN 0022-0000, E-ISSN 1090-2724, Vol. 81, no 7, 1311-1332 p.Article in journal (Refereed)
    Abstract [en]

    The propositional planning problem is a notoriously difficult computational problem, which remains hard even under strong syntactical and structural restrictions. Given its difficulty it becomes natural to study planning in the context of parameterized complexity. In this paper we continue the work initiated by Downey, Fellows and Stege on the parameterized complexity of planning with respect to the parameter "length of the solution plan." We provide a complete classification of the parameterized complexity of the planning problem under two of the most prominent syntactical restrictions, i.e., the so called PUBS restrictions introduced by Backstrom and Nebel and restrictions on the number of preconditions and effects as introduced by Bylander. We also determine which of the considered fixed-parameter tractable problems admit a polynomial kernel and which do not. (C) 2015 Elsevier Inc. All rights reserved.

  • 8.
    Levi, Richard
    et al.
    Solberga Project/Karolinska Institute and Centre for Neurotraumatology, Karolinska Hospital, Stockholm, Sweden.
    Hultling, C
    Solberga Project/Karolinska Institute and Centre for Neurotraumatology, Karolinska Hospital, Stockholm, Sweden.
    Westgren, N
    Solberga Project/Karolinska Institute and Centre for Neurotraumatology, Karolinska Hospital, Stockholm, Sweden.
    A computer assisted follow up system for spinal cord injury patients.1994In: Paraplegia, ISSN 0031-1758, Vol. 32, no 11, 736-742 p.Article in journal (Refereed)
    Abstract [en]

    The comprehensive care of patients with traumatic spinal cord injuries (SCI) necessitates, among other things, a structured, life-long follow up. The high consumption of medical care in chronic SCI patients, often a result of diseases affecting many different organ systems, soon causes the cumulated medical documentation to be extensive and therefore hard to survey. The possibilities for rational patient management, adequate quality assurance, and clinical research may improve considerably by computerisation of medical records. A computerised medical records system for SCI has recently been developed, using a semistructured medical record format for data input and a medical entity dictionary for facilitated data storage and retrieval. The principles for developing this computer-assisted follow up system are described.

  • 9.
    Poulsen, Kåre
    et al.
    Informatics and Mathematical Modelling Dept. Technical University of Denmark.
    Pop, Paul
    Linköping University, The Institute of Technology. Linköping University, Department of Computer and Information Science, ESLAB - Embedded Systems Laboratory.
    Izosimov, Viacheslav
    Linköping University, The Institute of Technology. Linköping University, Department of Computer and Information Science, ESLAB - Embedded Systems Laboratory.
    A Constraint Logic Programming Framework for the Synthesis of Fault-Tolerant Schedules for Distributed Embedded Systems2007In: 12th IEEE Conf. on Emerging Technologies and Factory Automation Work-In-Progress Section,2007, Patras, Greece: IEEE Computer Society Press , 2007, 756- p.Conference paper (Refereed)
    Abstract [en]

    We present a constraint logic programming (CLP) approach for synthesis of fault-tolerant hard real-time applications on distributed heterogeneous architectures. We address time-triggered systems, where processes and messages are statically scheduled based on schedule tables. We use process re-execution for recovering from multiple transient faults. We propose three scheduling approaches, which each present a trade-off between schedule simplicity and performance, (i) full transparency, (ii) slack sharing and (iii) conditional, and provide various degrees of transparency. We have developed a CLP framework that produces the fault-tolerant schedules, guaranteeing schedulability in the presence of transient faults. We show how the framework can be used to tackle design optimization problems.The proposed approach has been evaluated using extensive experiments.

  • 10.
    Nilsson, Marcus
    et al.
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Westring, Alexander
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    A decision support system for an improved article placement2017Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Warehouse storage is an important part of a business’ supply chain. This is where articles temporary are stored before they either are carried on to the next step of the production or to be delivered to the customers of the company. The largest part of the stock keeping often devoted to the order picking. Order picking includes the activities that are occurring when an article is being picked from its stored position and is being transported to the next step of the flow of the materials. The most time- consuming part of the order picking process are often the time to pinpoint and to get the hold of an article. This implies quite likely that an enhancement of the productivity could be realized, inter alia, through cut the transport distances. SKF Mekan AB is an industrial corporation whose primary occupation is to manufacture bearing housings. Currently, the business has a flawed inventory for stock keeping. A great many of the articles stored in the inventory, entitled 104C, are placed in regard to their measures, without any thought in regard of how frequently the articles are picked. In addition, the article placement that is used today is outdated, which has resulted in that a lot of articles are lacking a specific placement in the inventory. The purpose of storing articles in the inventory 104C is to cope with fluctuations in the next step of the manufacturing, which is the processing factory. The aim of the study is to find out how the article placement looks in the current situation and how decisions concerning article placement are determined and what issues occurs due to this. A decision support system has been developed which purpose is to give SKF Mekan AB decision basis regarding where the different kinds of articles should be placed to attain an increased efficiency in business’ stock keeping. The decision support system is adaptable to the extent that the user can adjust the parameters that are determining the article placement. The study has been accomplished by means of observations and interviews. With the help of the observations, the layout of the warehouse and the article placement has been mapped out and with the help of the interviews; the results concerning work models and decision-making of article placement has been answered. Through the observations and the interviews appeared that 42.5 % of the stocked pallets were misplaced and that 15.6 % of the stocked pallets lacked a specific placement in the warehouse. This results in that the truck operators has a hard time localizing the pallets, which leads to inefficient labouring. This causes delays in the next step of the supply chain; i. e. the processing factory, meaning the personnel has to wait for the articles to be delivered. With the articles picking frequency and the principle of family grouping as point of reference for the article placement SKF Mekan AB should be able to eliminate non-value adding activities in the supply chain, which should lead to an increased potential of profitability.

  • 11.
    Liang, Kai
    et al.
    Xidian University, Peoples R China.
    Zhao, Liqiang
    Xidian University, Peoples R China.
    Yang, Kun
    University of Essex, England.
    Zheng, Gan
    University of Essex, England; University of Luxembourg, Luxembourg.
    Ding, Wei
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    A Fair Power Splitting Algorithm for Simultaneous Wireless Information and Energy Transfer in CoMP Downlink Transmission2015In: Wireless personal communications, ISSN 0929-6212, E-ISSN 1572-834X, Vol. 85, no 4, 2687-2710 p.Article in journal (Refereed)
    Abstract [en]

    A power splitting approach for simultaneous wireless information and energy transfer is provided in this paper. We consider coordinated multipiont downlink transmission with M base stations (BSs) and J mobile stations (MSs). The main goal of this paper is to maximize per-MS data rate and receiving energy by dynamically optimizing transmitting beamformer. To improve fairness, this problem can be formulated to maximize the minimum rate of all J MSs with per-BS transmitting power constraints and per-MS receiving energy constraints, which is NP-hard problem. Minimum mean square error receiver, affine approximation and alternative convex optimization (ACO) methods are introduced to decompose the original NP-hard problem to several convex subproblems which can be solved by second-order cone programming with low rank (which is equal to the number of data streams) solutions, and then a fast heuristic algorithm is provided to solve the original problem. Numerical results show that the proposed algorithm can achieve fairness, and outperforms sum rate scheme in terms of fairness and outage probability. The fast convergency also demonstrates the proposed algorithms good performance.

  • 12.
    Servitja Robert, Maria
    Linköping University, Department of Mathematics, Mathematical Statistics . Linköping University, Faculty of Science & Engineering.
    A First Study on Hidden Markov Models and one Application in Speech Recognition2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Speech is intuitive, fast and easy to generate, but it is hard to index and easy to forget. What is more, listening to speech is slow. Text is easier to store, process and consume, both for computers and for humans, but writing text is slow and requires some intention. In this thesis, we study speech recognition which allows converting speech into text, making it easier both to create and to use information. Our tool of study is Hidden Markov Models which is one of the most important machine learning models in speech and language processing.

    The aim of this thesis is to do a rst study in Hidden Markov Models and understand their importance, particularly in speech recognition. We will go through three fundamental problems that come up naturally with Hidden Markov Models: to compute a likelihood of an observation sequence, to nd an optimal state sequence given an observation sequence and the model, and to adjust the model parameters. A solution to each problem will be given together with an example and the corresponding simulations using MatLab. The main importance lies in the last example, in which a rst approach to speech recognition will be done.

  • 13.
    Granström, Karl
    et al.
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    Lundquist, Christian
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    Orguner, Umut
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    A Gaussian Mixture PHD Filter for Extended Target Tracking2010In: Proceedings of the 13th International Conference on Information Fusion, 2010Conference paper (Refereed)
    Abstract [en]

    In extended target tracking, targets potentially produce more than one measurement per time step. Multiple extended targets are therefore usually hard to track, due to the resulting complex data association. The main contribution of this paper is the implementation of a Probability Hypothesis Density (PHD) filter for tracking of multiple extended targets. A general modification of the PHD filter to handle extended targets has been presented recently by Mahler, and the novelty in this work lies in the realisation of a Gaussian mixture PHD filter for extended targets. Furthermore, we propose a method to easily partition the measurements into a number of subsets, each of which is supposed to contain measurements that all stem from the same source. The method is illustrated in simulation examples, and the advantage of the implemented extended target PHD filter is shown in a comparison with a standard PHD filter.

  • 14.
    Granström, Karl
    et al.
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    Lundquist, Christian
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    Orguner, Umut
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    A Gaussian Mixture PHD Filter for Extended Target Tracking2010Report (Other academic)
    Abstract [en]

    In extended target tracking, targets potentially produce more than one measurement per time step. Multiple extended targets are therefore usually hard to track, due to the resulting complex data association. The main contribution of this paper is the implementation of a Probability Hypothesis Density (PHD) filter for tracking of multiple extended targets. A general modification of the PHD filter to handle extended targets has been presented recently by Mahler, and the novelty in this work lies in the realisation of a Gaussian mixture PHD filter for extended targets. Furthermore, we propose a method to easily partition the measurements into a number of subsets, each of which is supposed to contain measurements that all stem from the same source. The method is illustrated in simulation examples, and the advantage of the implemented extended target PHD filter is shown in a comparison with a standard PHD filter.

  • 15.
    Mensmann, Jörg
    et al.
    University of Münster, Germany.
    Ropinski, Timo
    University of Münster, Germany.
    Hinrichs, Klaus
    University of Münster, Germany.
    A GPU-Supported Lossless Compression Scheme for Rendering Time-Varying Volume Data2010In: VG'10 Proceedings of the 8th IEEE/EG international conference on Volume Graphics, IEEE , 2010, 109-116 p.Conference paper (Refereed)
    Abstract [en]

    Since the size of time-varying volumetric data sets typically exceeds the amount of available GPU and main memory, out-of-core streaming techniques are required to support interactive rendering. To deal with the performance bottlenecks of hard-disk transfer rate and graphics bus bandwidth, we present a hybrid CPU/GPU scheme for lossless compression and data streaming that combines a temporal prediction model, which allows to exploit coherence between time steps, and variable-length coding with a fast block compression algorithm. This combination becomes possible by exploiting the CUDA computing architecture for unpacking and assembling data packets on the GPU. The system allows near-interactive performance even for rendering large real-world data sets with a low signal-to-noise-ratio, while not degrading image quality. It uses standard volume raycasting and can be easily combined with existing acceleration methods and advanced visualization techniques.

  • 16.
    Burdakov, Oleg
    Parallel Algorithms Team, CERFACS, Toulouse Cedex, France.
    A greedy algorithm for the optimal basis problem1997In: BIT Numerical Mathematics, ISSN 0006-3835, E-ISSN 1572-9125, Vol. 37, no 3, 591-599 p.Article in journal (Refereed)
    Abstract [en]

    The following problem is considered. Given m+1 points {x i }0 m in R n which generate an m-dimensional linear manifold, construct for this manifold a maximally linearly independent basis that consists of vectors of the form x i x j . This problem is present in, e.g., stable variants of the secant and interpolation methods, where it is required to approximate the Jacobian matrix f′ of a nonlinear mappingf by using values off computed at m+1 points. In this case, it is also desirable to have a combination of finite differences with maximal linear independence. As a natural measure of linear independence, we consider the hadamard condition number which is minimized to find an optimal combination of m pairs {x i ,x j }. We show that the problem is not NP-hard, but can be reduced to the minimum spanning tree problem, which is solved by the greedy algorithm in O(m 2) time. The complexity of this reduction is equivalent to one m×n matrix-matrix multiplication, and according to the Coppersmith-Winograd estimate, is below O(n 2.376) for m=n. Applications of the algorithm to interpolation methods are discussed.

  • 17.
    Holmberg, Kaj
    et al.
    Linköping University, Department of Mathematics. Linköping University, The Institute of Technology.
    Yuan, Di
    Linköping University, Department of Mathematics. Linköping University, The Institute of Technology.
    A Lagrangian heuristic based branch-and-bound approach for the capacitated network design problem2000In: Operations Research, ISSN 0030-364X, E-ISSN 1526-5463, Vol. 48, no 3, 461-481 p.Article in journal (Refereed)
    Abstract [en]

    The capacitated network design problem is a multicommodity minimal cost network flow problem with fixed charges on the arcs and is well known to be NP-hard. The problem type is very common in the context of transportation networks, telecommunication networks, etc. In this paper we propose an efficient method for this problem, based on a Lagrangian heuristic within a branch-and-bound framework. The Lagrangian heuristic uses a Lagrangian relaxation to obtain easily solved subproblems and solves the Lagrangian dual by subgradient optimization. It also includes techniques for finding primal feasible solutions. The Lagrangian heuristic is then embedded into a branch-and-bound scheme that yields further primal improvements. Special penalty tests and cutting criteria are developed. The branch-and-bound scheme can either be an exact method that guarantees the optimal solution of the problem or be a quicker heuristic. The method has been tested on networks of various structures and sizes. Computational comparisons between this method and a state-of-the-art mixed-integer code are presented. The method is found to be capable of generating good feasible solutions to large-scale problems within reasonable time and data storage limits.

  • 18.
    Magnusson, Ulf
    Linköping University, Department of Computer and Information Science, RTSLAB - Real-Time Systems Laboratory. Linköping University, The Institute of Technology.
    A Linux-based, Web-oriented operating system designed to boot quickly2011Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This thesis describes the design and implementation of a Linux-based, Web-oriented operating system called Awesom-O, designed with a focus on short boot time and small disk footprint. Among other techniques for lowering boot time, a semi-automatic method for generating a Linux kernel of minimal size for a given platform is developed, making use of an interpreter for the Linux kernel’s configuration language, Kconfig. The boot process of the finished system is analyzed to identify limiting factors in lowering its boot time further, and techniques for overcoming these are suggested.

    Excluding the initial BIOS stage of the boot process, the boot time of the finished system—up until it is idling inside the web browser interface waiting for user input—is 3.8 seconds (2.1 seconds to a shell prompt, 1.7 seconds in the kernel) on an Acer Travelmate 8200 laptop with an Intel Core Duo CPU at 2.0 GHz and a Momentus 5400.2 SATA (ST9120821AS) hard drive; 2.4 seconds (1.6 seconds to a shell prompt, 1.1 seconds in the kernel) on a Celsius M460 workstation with an Intel Core 2 Quad CPU at 2.5 GHz and a Barracuda 7200.11 SATA hard drive (ST3500320AS); 4.6 and 4.0 seconds respectively for the same systems when booting from a USB 2.0 device (a ChipsBank CBM2080 USB 2.0 stick); and 12.6 seconds on the BeagleBoard (8 seconds in the bootloader—an obvious area for future improvement).

    The Web functionality in Awesom-O is implemented atop the Opera Linux Devices SDK: a software framework for integrating web browser functionality in small Linux-based systems.

  • 19.
    Axehill, Daniel
    et al.
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    Hansson, Anders
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    Gunnarsson, Fredrik
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    A Low-Complexity High-Performance Preprocessing Algorithm for Multiuser Detection using Gold Sequences2008Report (Other academic)
    Abstract [en]

    The optimum multiuser detection problem can be formulated as a maximum likelihood problem, which yields a binary quadratic programming problem to be solved. Generally this problem is NP-hard and is therefore hard to solve in real time. In this paper, a preprocessing algorithm is presented which makes it possible to detect some or all users optimally for a low computational cost if signature sequences with low cross correlation, e.g., Gold sequences, are used. The algorithm can be interpreted as, e.g., an adaptive tradeoff between parallel interference cancellation and successive interference cancellation. Simulations show that the preprocessing algorithm is able to optimally compute more than 94,% of the bits in the problem when the users are time-synchronous, even though the system is heavily loaded and affected by noise. Any remaining bits, not computed by the preprocessing algorithm, can either be computed by a suboptimal detector or an optimal detector. Simulations of the time-synchronous case show that if a suboptimal detector is chosen, the bit error rate (BER) rate is significantly reduced compared with using the suboptimal detector alone.

  • 20.
    Axehill, Daniel
    et al.
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    Hansson, Anders
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    Gunnarsson, Fredrik
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    A Low-Complexity High-Performance Preprocessing Algorithm for Multiuser Detection using Gold Sequences2008In: IEEE Transactions on Signal Processing, ISSN 1053-587X, E-ISSN 1941-0476, Vol. 56, no 9, 4377-4385 p.Article in journal (Refereed)
    Abstract [en]

    The optimum multiuser detection problem can be formulated as a maximum likelihood problem, which yields a binary quadratic programming problem to be solved. Generally this problem is NP-hard and is therefore hard to solve in real time. In this paper, a preprocessing algorithm is presented which makes it possible to detect some or all users optimally for a low computational cost if signature sequences with low cross correlation, e.g., Gold sequences, are used. The algorithm can be interpreted as, e.g., an adaptive tradeoff between parallel interference cancellation and successive interference cancellation. Simulations show that the preprocessing algorithm is able to optimally compute more than 94,% of the bits in the problem when the users are time-synchronous, even though the system is heavily loaded and affected by noise. Any remaining bits, not computed by the preprocessing algorithm, can either be computed by a suboptimal detector or an optimal detector. Simulations of the time-synchronous case show that if a suboptimal detector is chosen, the bit error rate (BER) rate is significantly reduced compared with using the suboptimal detector alone.

  • 21.
    Köhn, Dagmar
    et al.
    Institute for Computer Science Universität Rostock.
    Strömbäck, Lena
    Linköping University, The Institute of Technology. Linköping University, Department of Computer and Information Science, IISLAB - Laboratory for Intelligent Information Systems.
    A method for Semi-automatic Standard Integration in Systems Biology2008In: Database and Expert Systems Applications,2008, Heidelberg, Germany: Springer , 2008, 745-752 p.Conference paper (Refereed)
    Abstract [en]

    The development of standards for biological pathways has led to a huge amount of model data stored in a variety of different formats represented in XML (e. g. SBML) or OWL (e. g. BioPAX). As a result, there is an urgent need for the conversion of data between different formats, especially between XML and OWL data. The fact that that transformation is hard to realize hampers the integration of data in the area. Addressing this problem, the following article proposes a general, semi-automatic solution by suggesting the transformation of XML Schema based data into an OWL format. The general solution presented here will support biologists by offering them a way to query data of any format and as well compare different data files or schemas to each other using OWL as a common format for matching and providing a backwards transformation to XML Schema. The paper presents a first architectural approach and its prototype implementation. The evaluation showed that the approach is promising.

  • 22.
    Angelsmark, Ola
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Computer and Information Science, TCSLAB - Theoretical Computer Science Laboratory.
    Thapper, Johan
    Linköping University, The Institute of Technology. Linköping University, Department of Mathematics, Applied Mathematics.
    A Microstructure Based Approach to Constraint Satisfaction Optimisation Problems2005In: The 18th International FLAIRS Conference,2005, Menlo Park, CA, USA: AAAI Press , 2005, 155- p.Conference paper (Refereed)
    Abstract [en]

    We study two constraint satisfaction optimisation problems: The Max Value problem for CSPs, which, somewhat simplified, aims at maximising the sum of the (weighted) variable values in the solution, and the Max Ind problem, where the goal is to find a satisfiable subinstance of the original instance containing as many variables as possible. Both problems are NP-hard to approximate within n^(1-e), e>0, where n is the number of variables in the problems, which implies that it is of interest to find exact algorithms. By exploiting properties of the microstructure, we construct algorithms for solving instances of these problems with small domain sizes, and then, using a probabilistic reasoning, we show how to get algorithms for more general versions of the problems. The resulting algorithms have running times of O((0.585d)^n) for Max Value (d,2)-CSP, and O((0.503d)^n) for MaxInd (d,2)-CSP. Both algorithms represent the best known theoretical bounds for their respective problem, and, more importantly, the methods used are applicable to a wide range of optimisation problems. 

  • 23.
    Ekström, Joakim
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    A MILP approximation approach for finding optimal toll locations and levels in elastic demand traffic networks2010In: TRANSPORTATION AND URBAN SUSTAINABILITY: Proceedings of the 15th International Conference of Hong Kong Society for Transportation Studies (HKSTS) / [ed] Sumalee, A; Lam, WHK; Ho, HW; Siu, B, Hong Kong, China: Hong Kong Society for Transportation Studies , 2010, 107-114 p.Conference paper (Refereed)
    Abstract [en]

    The toll design problem (TDP) is to find optimal toll locations and corresponding toll levels in a congestion pricing scheme. The TDP can be formulated as a non-convex mathematical program, in which the road users are assumed to be distributed according to a user-equilibrium with elastic demand. This program is hard to solve due to non-convexity and non-smoothness. In this paper, the TDP is approximated by a mixed integer linear program (MILP), in which the non-linear functions of the TDP are approximated by piecewise linear ones. The MILP can be solved to its global optimal solution by known methods, and its optimal solution will give a lower bound on the optimal solution to the TDP. By iteratively updating the MILP approximation, the error introduced by the approximation is reduced, and for a test network with nine nodes and 18 links, the global optimal solution is obtained.

  • 24.
    Rocha, Andre
    et al.
    Universidade Nova de Lisboa, Caparica, Portugal .
    Ribeiro, Luis
    Universidade Nova de Lisboa, Caparica, Portugal .
    Barata, Jose
    Universidade Nova de Lisboa, Caparica, Portugal .
    A Multi Agent Architecture to Support Self-organizing Material Handling2014In: Technological Innovation for Collective Awareness Systems: 5th IFIP WG 5.5/SOCOLNET Doctoral Conference on Computing, Electrical and Industrial Systems, DoCEIS 2014, Costa de Caparica, Portugal, April 7-9, 2014. Proceedings / [ed] Luis M. Camarinha-Matos, Nuno S. Barrento, Ricardo Mendonça, Springer Berlin/Heidelberg, 2014, Vol. 423, 93-100 p.Chapter in book (Other academic)
    Abstract [en]

    Emerging market conditions press current shop floors hard. Mass customization implies that manufacturing system have to be extremely dynamic when handling variety and batch size. Hence, the ability to quickly reconfigure the system is paramount. This involves both the stations that carry out the production processes and the transport system. Traditionally system reconfiguration issues have been approached from a optimization point of view. This means allocating a certain batch of work to specific machines/stations in an optimal schedule. Although in a an abstract way these solutions are elegant and sound sometimes the number and nature of their base assumptions are unrealistic. Approaching the problem from a self-organizing perspective offers the advantage of attaining a fair solution in a concrete environment and as a reaction of the current operational conditions. Even if optimality cannot be ensured the solutions attained and the online re-adjustments render the system generally robust. This works extends the IDEAS Agent Development Environment (IADE) developed in the FP7 Instantly Deployable Evolvable Assembly Systems (IDEAS) project which has demonstrated the basic concepts of the proposed approach. The main architectural changes are presented and justified and the prospects for the analysis and self-organizing control are presented.

  • 25.
    Holmberg, Kaj
    et al.
    Linköping University, Department of Mathematics. Linköping University, The Institute of Technology.
    Yuan, Di
    Linköping University, Department of Mathematics. Linköping University, The Institute of Technology.
    A multicommodity network-flow problem with side constraints on paths solved by column generation2003In: INFORMS journal on computing, ISSN 1091-9856, Vol. 15, no 1, 42-57 p.Article in journal (Refereed)
    Abstract [en]

    The multicommodity network-flow model concerns routing of a number of commodities through a capacitated network at minimal cost. In the basic model, it is assumed that for each commodity, the flow can be routed on any path connecting its origin and its destination. In telecommunication applications, where a commodity represents a communication pair, there are often additional time-delay or reliability requirements on paths that are used for routing. These requirements may vary by communication pair, represented by different priority classes. In this paper, we extend the basic multicommodity network-flow model to include such side constraints on paths. The extended problem is NP-hard with the constrained shortest-path problem as a special case. To solve the extended model, we use a column-generation approach, in which the solution is built up successively by path generation. The side constraints are efficiently handled in the path-generation subproblem. We further discuss various enhancements of this approach. Computational results show that the column-generation approach provides an efficient way for solving the extended model, even for fairly large networks.

  • 26.
    Aghighi, Meysam
    et al.
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, Faculty of Science & Engineering.
    Bäckström, Christer
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, Faculty of Science & Engineering.
    A Multi-parameter Complexity Analysis of Cost-optimal and Net-benefit Planning2016Conference paper (Refereed)
    Abstract [en]

    Aghighi and Bäckström have previously studied cost-optimal planning (COP) and net-benefit planning (NBP) for three action cost domains: the positive integers (Z_+), the non-negative integers (Z_0) and the positive rationals (Q_+). These were indistinguishable under standard complexity analysis for both problems, but separated for COP using parameterised complexity analysis. With the plan cost, k, as parameter, COP was W[2]-complete for Z_+, but para-NP-hard for both Z_0 and Q_+, i.e. presumably much harder. NBP was para-NP-hard for all three domains, thus remaining unseparable. We continue by considering combinations with several additional parameters and also the non-negative rationals (Q_0). Examples of new parameters are the plan length, l, and the largest denominator of the action costs, d. Our findings include: (1) COP remains W[2]-hard for all domains, even if combining all parameters; (2) COP for Z_0 is in W[2] for the combined parameter {k,l}; (3) COP for Q_+ is in W[2] for {k,d} and (4) COP for Q_0 is in W[2] for {k,d,l}. For NBP we consider further additional parameters, where the most crucial one for reducing complexity is the sum of variable utilities. Our results help to understand the previous results, eg. the separation between Z_+ and Q_+ for COP, and to refine the previous connections with empirical findings.

  • 27.
    Hendeby, Gustaf
    et al.
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    Karlsson, Rickard
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    Gustafsson, Fredrik
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    A New Formulation of the Rao-Blackwellized Particle Filter2007Report (Other academic)
    Abstract [en]

    For performance gain and efficiency it is important to utilize model structure in particle filtering. Applying Bayes- rule, present linear Gaussian substructure can be efficiently handled by a bank of Kalman filters. This is the standard formulation of the Rao-Blackwellized particle filter (RBPF), by some authors denoted the marginalized particle filter (MPF), and usually presented in a way that makes it hard to implement in an object oriented fashion. This paper discusses how the solution can be rewritten in order to increase the understanding as well as simplify the implementation and reuse of standard filtering components, such as Kalman filter banks and particle filters. Calculations show that the new algorithm is equivalent to the classical formulation, and the new algorithm is exemplified in a target tracking simulation study.

  • 28.
    Hendeby, Gustaf
    et al.
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    Karlsson, Rickard
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    Gustafsson, Fredrik
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    A New Formulation of the Rao-Blackwellized Particle Filter2007In: Proceedings of the 14th IEEE/SP Statistical Signal Processing Workshop, 2007, 84-88 p.Conference paper (Refereed)
    Abstract [en]

    For performance gain and efficiency it is important to utilize model structure in particle filtering. Applying Bayes- rule, present linear Gaussian substructure can be efficiently handled by a bank of Kalman filters. This is the standard formulation of the Rao-Blackwellized particle filter (RBPF), by some authors denoted the marginalized particle filter (MPF), and usually presented in a way that makes it hard to implement in an object oriented fashion. This paper discusses how the solution can be rewritten in order to increase the understanding as well as simplify the implementation and reuse of standard filtering components, such as Kalman filter banks and particle filters. Calculations show that the new algorithm is equivalent to the classical formulation, and the new algorithm is exemplified in a target tracking simulation study.

  • 29.
    Broitman, Esteban
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    A new method for in-situ measurement of nano-friction and nano-wear of thin films by using the Triboindenter TI-9502014In: Nanobrucken 2014, Saarbrucken, Germany: INM - Leibniz Institute for New Materials , 2014, 24- p.Conference paper (Other academic)
    Abstract [en]

    The Triboindenter present many advantages for the measurement of friction and wear at the nanoscale. A reciprocating multi-cycle linear test can be programmed, from where it is possible to obtain simultaneously the friction force and wear rate from the lateral force and vertical displacement sensors, respectively. The friction values have high precision but the wear data is usually wrong in long duration tests because the drift rate is only measured just before the test start. Alternatively, one can program the SPM scanning mode of the instrument with a high load in order to produce the wear of the surface. At the end of the experiment, a squared hole is produced which can be measured using the SPM facility of the system. However, this wear experiment does not allow the simultaneous measurement of the friction coefficient.In this talk I will present a new methodology to measure in-situ the friction and wear of thin films using a Triboindenter TI-950 from Hysitron. I will show how the possible changes of drift rate during long-time tests can be overcome, obtaining simultaneous precise values of friction and wear rate as a function of time. I will discuss how the Triboimage® software can be adapted to this methodology in order to get realistic values of friction and wear. Finally I will show some results for soft (H < 1GPa) Pb films and very hard (H ~ 35 GPa) nitride coatings

  • 30.
    Eriksson, Olle
    Linköping University, Department of Mathematics, Statistics. Linköping University, Faculty of Arts and Sciences.
    A new program for fast emission calculations based on the COPERT III modelManuscript (Other academic)
    Abstract [en]

    Emissions from road traffic are hard to measure and therefore usually estimated in models. In this paper the construction of the widely used COPERT III model is examined, and the model is rewritten in mathematical notation. The original COPERT III software is easily handled but is not suitable as an emissiondata generating tool for fast calculations over a broad variety of driving conditions, which is required for sensitivity analysis. An alternative program has been developed to meet the desired properties of such a tool. The construction of the alternative program is discussed together with its new abilities and restrictions. Some differences between the results from the original COPERT III software and the alternative program are analyzed and discussed.

  • 31.
    Psoma, Sotiria D.
    et al.
    Cranfield University, Cranfield Health, Cranfield, Bedfordshire, UK.
    D. van der Wal, Peter
    EPFL, IMT-SAMLAB, Switzerland.
    Frey, Olivier
    EPFL, IMT-SAMLAB, Switzerland.
    de Rooij, Nicolaas F.
    EPFL, IMT-SAMLAB, Switzerland.
    Turner, Anthony P. F.
    Cranfield University, UK.
    A novel enzyme entrapment in SU-8 microfabricated films for glucose micro-biosensors2010In: Biosensors & bioelectronics, ISSN 0956-5663, E-ISSN 1873-4235, Vol. 26, no 4, 1582-1587 p.Article in journal (Refereed)
    Abstract [en]

    The present work investigates the utilisation of the widely used SU-8 photoresist as an immobilisation matrix for glucose oxidase (GOx) for the development of glucose micro-biosensors. The strong advantage of the proposed approach is the simultaneous enzyme entrapment during the microfabrication process within a single step, which is of high importance for the simplification of the BioMEMS procedures. Successful encapsulation of the enzyme GOx in "customised" SU-8 microfabricated structures was achieved through optimisation of the one-step microfabrication process. Although the process involved contact with organic solvents, UV-light exposure, heating for pre- and post-bake and enzyme entrapment in a hard and rigid epoxy resin matrix, the enzyme retained its activity after encapsulation in SU-8. Measurements of the immobilised enzymes activity inside the SU-8 matrix were carried out using amperometric detection of hydrogen peroxide in a 3-electrode setup. Films without enzyme showed negligible variation in current upon the addition of glucose, as opposed to films with encapsulated enzyme which showed a very clear increase in current. Experiments using films of increased thickness or enzyme concentration, showed a higher response, thus proving that the enzyme remained active not only on the films surface, but also inside the matrix as well. The proposed enzyme immobilisation in SU-8 films opens up new possibilities for combining BioMEMS with biosensors and organic electronics.

  • 32.
    Ankelhed, Daniel
    et al.
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    Helmersson, Anders
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    Hansson, Anders
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    A Partially Augmented Lagrangian Method for Low Order H-Infinity Controller Synthesis Using Rational Constraints2011Report (Other academic)
    Abstract [en]

    When designing robust controllers, H-infinity synthesis is a common tool touse. The controllers that result from these algorithms are typically of very high order, which complicates implementation. However, if a constraint on the maximum order of the controller is set, that is lower than the order of the (augmented) system, the problem becomes nonconvex and it is relatively hard to solve. These problems become very complex, even when the order of the system is low.

    The approach used in this work is based on formulating the constraint onthe maximum order of the controller as a polynomial (or rational) equation.This equality constraint is added to the optimization problem of minimizingan upper bound on the H-innity norm of the closed loop system subjectto linear matrix inequality (LMI) constraints. The problem is then solvedby reformulating it as a partially augmented Lagrangian problem where theequality constraint is put into the objective function, but where the LMIsare kept as constraints.

    The proposed method is evaluated together with two well-known methodsfrom the literature. The results indicate that the proposed method hascomparable performance in most cases, especially if the synthesized con-troller has many parameters, which is the case if the system to be controlledhas many input and output signals.

  • 33.
    Ankelhed, Daniel
    et al.
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    Helmersson, Anders
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    Hansson, Anders
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    A Primal-Dual Method for Low Order H-Infinity Controller Synthesis2010Report (Other academic)
    Abstract [en]

    When designing robust controllers, H-infinity synthesis is a common tool to use. The controllers that result from these algorithms are typically of very high order, which complicates implementation. However, if a constraint on the maximum order of the controller is set, that is lower than the order of the (augmented) system, the problem becomes nonconvex and it is relatively hard to solve. These problems become very complex, even when the order of the system is low.

    The approach used in this work is based on formulating the constraint on the maximum order of the controller as a polynomial (or rational) equation. By using the fact that the polynomial (or rational) is non-negative on the feasible set, the problem is reformulated as an optimization problem where the nonconvex function is to be minimized over a convex set defined by linear matrix inequalities.

    The proposed method is evaluated together with a well-known method from the literature. The results indicate that the proposed method performs slightly better.

  • 34.
    Ankelhed, Daniel
    et al.
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    Helmersson, Anders
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    Hansson, Anders
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    A Primal-Dual Method for Low Order H-Infinity Controller Synthesis2010In: Proceedings of Reglermöte 2010, Lund, 2010Conference paper (Other academic)
    Abstract [en]

    When designing robust controllers, H-infinity synthesis is a common tool to use. The controllers that result from these algorithms are typically of very high order, which complicates implementation. However, if a constraint on the maximum order of the controller is set, that is lower than the order of the (augmented) system, the problem becomes nonconvex and it is relatively hard to solve. These problems become very complex, even when the order of the system is low.

    The approach used in this work is based on formulating the constraint on the maximum order of the controller as a polynomial (or rational) equation. By using the fact that the polynomial (or rational) is non-negative on the feasible set, the problem is reformulated as an optimization problem where the nonconvex function is to be minimized over a convex set defined by linear matrix inequalities.

    The proposed method is evaluated together with a well-known method from the literature. The results indicate that the proposed method performs slightly better.

  • 35.
    Ankelhed, Daniel
    et al.
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    Helmersson, Anders
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    Hansson, Anders
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    A Primal-Dual Method for Low Order H-Infinity Controller Synthesis2009In: Proceedings of the 48th IEEE Conference on Decision and Control held jointly with the 28th Chinese Control Conference, IEEE , 2009, 6674-6679 p.Conference paper (Refereed)
    Abstract [en]

    When designing robust controllers, H-infinity synthesisis a common tool to use. The controllers that result from these algorithms are typically of very high order, which complicates implementation. However, if a constraint on the maximum order of the controller is set, that is lower than the order of the (augmented) system, the problem becomes nonconvex and it is relatively hard to solve. These problems become very complex,even when the order of the system is low.

    The approach used in this work is based on formulating the constraint on the maximum order of the controller as a polynomial (or rational) equation. By using the fact that the polynomial (or rational) is non-negative on the feasible set, the problem is reformulated as an optimization problem where the nonconvex function is to be minimized over a convex set defined by linear matrix inequalities.

    The proposed method is evaluated together with a wellknown method from the literature. The results indicate that the proposed method performs slightly better.

  • 36.
    Karresand, Martin
    Linköping University, Department of Electrical Engineering.
    A Proposed Taxonomy of Software Weapons2002Independent thesis Basic level (professional degree)Student thesis
    Abstract [en]

    The terms and classification schemes used in the computer security field today are not standardised. Thus the field is hard to take in, there is a risk of misunderstandings, and there is a risk that the scientific work is being hampered.

    Therefore this report presents a proposal for a taxonomy of software based IT weapons. After an account of the theories governing the formation of a taxonomy, and a presentation of the requisites, seven taxonomies from different parts of the computer security field are evaluated. Then the proposed new taxonomy is introduced and the inclusion of each of the 15 categories is motivated and discussed in separate sections. Each section also contains a part briefly outlining the possible countermeasures to be used against weapons with that specific characteristic.

    The final part of the report contains a discussion of the general defences against software weapons, together with a presentation of some open issues regarding the taxonomy. There is also a part discussing possible uses for the taxonomy. Finally the report is summarised.

  • 37.
    Bagger-Sjoback, Dan
    et al.
    Karolinska Institute, Sweden; Karolinska University Hospital, Sweden.
    Stromback, Karin
    Academic Hospital, Sweden.
    Hakizimana, Pierre
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Health Sciences. Karolinska Institute, Sweden.
    Plue, Jan
    Stockholm University, Sweden.
    Larsson, Christina
    Karolinska University Hospital, Sweden.
    Hultcrantz, Malou
    Karolinska Institute, Sweden; Karolinska University Hospital, Sweden.
    Papatziamos, Georgios
    Karolinska University Hospital, Sweden.
    Smeds, Henrik
    Karolinska Institute, Sweden; Karolinska University Hospital, Sweden.
    Danckwardt-Lilliestrom, Niklas
    Academic Hospital, Sweden.
    Hellstrom, Sten
    Karolinska Institute, Sweden; Karolinska University Hospital, Sweden.
    Johansson, Ann
    Karolinska University Hospital, Sweden.
    Tideholm, Bo
    Karolinska University Hospital, Sweden.
    Fridberger, Anders
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Health Sciences. Karolinska Institute, Sweden.
    A Randomised, Double Blind Trial of N-Acetylcysteine for Hearing Protection during Stapes Surgery2015In: PLoS ONE, ISSN 1932-6203, Vol. 10, no 3, e0115657- p.Article in journal (Refereed)
    Abstract [en]

    Background Otosclerosis is a disorder that impairs middle ear function, leading to conductive hearing loss. Surgical treatment results in large improvement of hearing at low sound frequencies, but high-frequency hearing often suffers. A likely reason for this is that inner ear sensory cells are damaged by surgical trauma and loud sounds generated during the operation. Animal studies have shown that antioxidants such as N-Acetylcysteine can protect the inner ear from noise, surgical trauma, and some ototoxic substances, but it is not known if this works in humans. This trial was performed to determine whether antioxidants improve surgical results at high frequencies. Methods We performed a randomized, double-blind and placebo-controlled parallel group clinical trial at three Swedish university clinics. Using block-stratified randomization, 156 adult patients undergoing stapedotomy were assigned to intravenous N-Acetylcysteine (150 mg/kg body weight) or matching placebo (1:1 ratio), starting one hour before surgery. The primary outcome was the hearing threshold at 6 and 8 kHz; secondary outcomes included the severity of tinnitus and vertigo. Findings One year after surgery, high-frequency hearing had improved 2.7 +/- 3.8 dB in the placebo group (67 patients analysed) and 2.4 +/- 3.7 dB in the treated group (72 patients; means +/- 95% confidence interval, p = 0.54; linear mixed model). Surgery improved tinnitus, but there was no significant intergroup difference. Post-operative balance disturbance was common but improved during the first year, without significant difference between groups. Four patients receiving N-Acetylcysteine experienced mild side effects such as nausea and vomiting. Conclusions N-Acetylcysteine has no effect on hearing thresholds, tinnitus, or balance disturbance after stapedotomy.

  • 38.
    Brandouy, Olivier
    et al.
    Sorbonne Grad Business Sch, France .
    Corelli, Angelo
    Linköping University, Department of Management and Engineering, Production Economics. Linköping University, The Institute of Technology.
    Veryzhenko, Iryna
    ENSAM Paristech, France .
    Waldeck, Roger
    Telecom Bretagne, France .
    A re-examination of the "zero is enough" hypothesis in the emergence of financial stylized facts2012In: Journal of Economic Interaction and Coordination, ISSN 1860-711X, E-ISSN 1860-7128, Vol. 7, no 2, 223-248 p.Article in journal (Refereed)
    Abstract [en]

    In recent years, a growing literature has claimed that the market microstructure is sufficient to generate the so-called stylized facts without any reference to the behaviour of market players. Indeed, qualitative stylized-facts can be generated with zero-intelligence traders (ZITs) but we stress that they are without any quantitative predictive power. In this paper we show that in most of the cases, such qualitative stylized facts hide unrealistic price motions at the intraday level and ill-calibrated return processes as well. To generate realistic price motions and return series with adequate quantitative values is out-of-reach using pure ZIT populations. To do so, one must increasingly constrain agents choices to a point where it is hard to claim that their behaviour is completely random. In addition we show that even with highly constrained ZIT agents, one cannot reproduce real time series from these. Except in a few cases, first order moments of ZITs never equal real data ones. We therefore claim that stylized facts produced by means of ZIT agents are useless for financial engineering.

  • 39.
    Bäckström, Christer
    et al.
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    Jonsson, Peter
    Linköping University, Department of Computer and Information Science, Software and Systems. Linköping University, The Institute of Technology.
    A Refined View of Causal Graphs and Component Sizes: SP-Closed Graph Classes and Beyond2013In: The journal of artificial intelligence research, ISSN 1076-9757, Vol. 47, 575-611 p.Article in journal (Refereed)
    Abstract [en]

    The causal graph of a planning instance is an important tool for planning both in practice and in theory. The theoretical studies of causal graphs have largely analysed the computational complexity of planning for instances where the causal graph has a certain structure, often in combination with other parameters like the domain size of the variables. Chen and Giménez ignored even the structure and considered only the size of the weakly connected components. They proved that planning is tractable if the components are bounded by a constant and otherwise intractable. Their intractability result was, however, conditioned by an assumption from parameterised complexity theory that has no known useful relationship with the standard complexity classes. We approach the same problem from the perspective of standard complexity classes, and prove that planning is NP-hard for classes with unbounded components under an additional restriction we refer to as SP-closed. We then argue that most NP-hardness theorems for causal graphs are difficult to apply and, thus, prove a more general result; even if the component sizes grow slowly and the class is not densely populated with graphs, planning still cannot be tractable unless the polynomial hierachy collapses. Both these results still hold when restricted to the class of acyclic causal graphs. We finally give a partial characterization of the borderline between NP-hard and NP-intermediate classes, giving further insight into the problem.

  • 40.
    Larsson, Åsa
    et al.
    Linköping University, Department of Social and Welfare Studies, Health, Activity, Care. Linköping University, Faculty of Health Sciences.
    Haglund, Lena
    Linköping University, Department of Social and Welfare Studies, Health, Activity, Care. Linköping University, Faculty of Health Sciences.
    Hagberg, Jan-Erik
    Linköping University, Department of Social and Welfare Studies, Society, Diversity, Identity . Linköping University, Faculty of Arts and Sciences.
    A review of research with elderly people as respondents reported in occupational therapy journals2008In: Scandinavian Journal of Occupational Therapy, ISSN 1103-8128, Vol. 15, no 2, 116-126 p.Article in journal (Refereed)
    Abstract [en]

    The aim of this article is to review research presented in occupational therapy journals with the elderly as respondents. With an increasing number of elderly people in society research including the elderly should play a vital role within occupational therapy especially since emphasis on subjective experience is an important factor in the core constructs of occupation. Through a review of six occupational therapy journals, covering the period 2001--2006, it was discovered that 15% of the total number of articles included the elderly as respondents. The published articles with the elderly as respondents were mainly quantitative with the most frequent subject being instrument developing and testing. Most studies had a population group of mixed ages, making it hard to draw conclusions concerning the elderly population. The conclusion is that more research of a qualitative nature reflecting the subjective perspectives of the elderly is needed, especially regarding the oldest age group since this is the fastest growing and there is still limited knowledge regarding their perspective on matters concerning their everyday lives and their doings. Technological developments are implied to benefit elderly people but more research and discussion is needed on how this will affect both the elderly and occupational therapy theory and practice.

  • 41.
    Suri, Bharath
    et al.
    Linköping University, Department of Computer and Information Science, ESLAB - Embedded Systems Laboratory. Linköping University, The Institute of Technology.
    Bordoloi, Unmesh D.
    Linköping University, Department of Computer and Information Science, ESLAB - Embedded Systems Laboratory. Linköping University, The Institute of Technology.
    Eles, Petru
    Linköping University, Department of Computer and Information Science, ESLAB - Embedded Systems Laboratory. Linköping University, The Institute of Technology.
    A Scalable GPU-Based Approach to Accelerate the Multiple-Choice Knapsack Problem2012In: Design Automation and Test in Europe (DATE12) (short paper), Dresden, Germany, March 12-16, 2012., IEEE , 2012, 1126-1129 p.Conference paper (Refereed)
    Abstract [en]

    Variants of the 0-1 knapsack problem manifest themselves at the core of several system-level optimization problems. The running times of such system-level optimization techniques are adversely affected because the knapsack problem is NP-hard. In this paper, we propose a new GPU-based approach to accelerate the multiple-choice knapsack problem, which is a general version of the 0-1 knapsack problem. Apart from exploiting the parallelism offered by the GPUs, we also employ a variety of GPU-specific optimizations to further accelerate the running times of the knapsack problem. Moreover, our technique is scalable in the sense that even when running large instances of the multiple-choice knapsack problems, we can efficiently utilize the GPU compute resources and memory bandwidth to achieve significant speedups.

  • 42.
    Semb, Gunvor
    et al.
    Division of Dentistry, University of Manchester , Manchester , UK; Department of Plastic and Reconstructive Surgery , Oslo University Hospital Rikshospitalet , Oslo , Norway; Department of Speech and Language Disorders , Statped sørøst , Oslo , Norway..
    Enemark, Hans
    Cleft Palate Center , Aarhus , Denmark.
    Friede, Hans
    Department of Orthodontics , Sahlgrenska Academy, University of Gothenburg , Sweden.
    Paulin, Gunnar
    Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Maxillofacial Unit.
    Lilja, Jan
    Department of Plastic Surgery , Sahlgrenska Academy, University of Gothenburg , Sweden.
    Rautio, Jorma
    Cleft Palate and Craniofacial Center, Helsinki University Central Hospital , Helsinki , Finland.
    Andersen, Mikael
    Copenhagen Cleft Palate Center, University Hospital of Copenhagen , Denmark.
    Åbyholm, Frank
    Department of Plastic and Reconstructive Surgery , Oslo University Hospital Rikshospitalet , Oslo , Norway.
    Lohmander, Anette
    Division of Speech and Language Pathology , Karolinska Institute, and Karolinska University Hospital , Stockholm , Sweden.
    Shaw, William
    Division of Dentistry, University of Manchester , Manchester , UK.
    Mølsted, Kirsten
    Copenhagen Cleft Palate Center, University Hospital of Copenhagen , Denmark.
    Heliövaara, Arja
    Cleft Palate and Craniofacial Center, Helsinki University Central Hospital , Helsinki , Finland.
    Bolund, Stig
    Copenhagen Cleft Palate Center, University Hospital of Copenhagen , Denmark.
    Hukki, Jyri
    Cleft Palate and Craniofacial Center, Helsinki University Central Hospital , Helsinki , Finland.
    Vindenes, Hallvard
    Centre for Cleft Lip and Palate, Bergen University Hospital Haukeland , Bergen , Norway.
    Davenport, Peter
    Greater Manchester Cleft Lip and Palate Unit , Royal Manchester Childrens' Hospital , Manchester , UK.
    Arctander, Kjartan
    Department of Plastic and Reconstructive Surgery , Oslo University Hospital Rikshospitalet , Oslo , Norway.
    Larson, Ola
    Stockholm Craniofacial Team , Karolinska University Hospital , Stockholm , Sweden.
    Berggren, Anders
    Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Hand and Plastic Surgery.
    Whitby, David
    Greater Manchester Cleft Lip and Palate Unit , Royal Manchester Childrens' Hospital , Manchester , UK.
    Leonard, Alan
    The Royal Hospital for Sick Children , Belfast , N. Ireland.
    Neovius, Erik
    Stockholm Craniofacial Team , Karolinska University Hospital , Stockholm , Sweden.
    Elander, Anna
    Department of Plastic Surgery , Sahlgrenska Academy, University of Gothenburg , Sweden.
    Willadsen, Elisabeth
    Department of Nordic Studies and Linguistics , University of Copenhagen , Denmark.
    Bannister, R. Patricia
    Greater Manchester Cleft Lip and Palate Unit , Royal Manchester Childrens' Hospital , Manchester , UK.
    Bradbury, Eileen
    Private Practitioner , Manchester , UK.
    Henningsson, Gunilla
    Stockholm Craniofacial Team , Karolinska University Hospital , Stockholm , Sweden.
    Persson, Christina
    Institute of Neuroscience and Physiology, Speech and Language; Division for Speech and Language Pathology , Sahlgrenska University Hospital , Gothenburg , Sweden Pathology Unit , Sahlgrenska Academy, University of Gothenburg , Sweden; .
    Eyres, Philip
    Division of Dentistry, University of Manchester , Manchester , UK.
    Emborg, Berit
    Cleft Palate Center , Aarhus , Denmark.
    Kisling-Møller, Mia
    Division of Dentistry, University of Manchester , Manchester , UK.
    Küseler, Annelise
    Division of Dentistry, University of Manchester , Manchester , UK.
    Granhof Black, Birthe
    Division of Dentistry, University of Manchester , Manchester , UK.
    Schöps, Antje
    Copenhagen Cleft Palate Center, University Hospital of Copenhagen , Denmark.
    Bau, Anja
    Copenhagen Cleft Palate Center, University Hospital of Copenhagen , Denmark.
    Boers, Maria
    Copenhagen Cleft Palate Center, University Hospital of Copenhagen , Denmark.
    Søgaard Andersen, Helene
    Copenhagen Cleft Palate Center, University Hospital of Copenhagen , Denmark.
    Jeppesen, Karin
    Copenhagen Cleft Palate Center, University Hospital of Copenhagen , Denmark.
    Marxen, Dorte
    Copenhagen Cleft Palate Center, University Hospital of Copenhagen , Denmark.
    Paaso, Marjukka
    Cleft Palate and Craniofacial Center, Helsinki University Central Hospital , Helsinki , Finland.
    Hölttä, Elina
    Cleft Palate and Craniofacial Center, Helsinki University Central Hospital , Helsinki , Finland.
    Alaluusua, Suvi
    Cleft Palate and Craniofacial Center, Helsinki University Central Hospital , Helsinki , Finland.
    Turunen, Leena
    Cleft Palate and Craniofacial Center, Helsinki University Central Hospital , Helsinki , Finland.
    Humerinta, Kirsti
    Cleft Palate and Craniofacial Center, Helsinki University Central Hospital , Helsinki , Finland.
    Elfving-Little, Ulla
    Cleft Palate and Craniofacial Center, Helsinki University Central Hospital , Helsinki , Finland.
    Tørdal, Inger Beate
    Department of Speech and Language Disorders , Statped sørøst , Oslo , Norway.
    Kjøll, Lillian
    Department of Speech and Language Disorders , Statped sørøst , Oslo , Norway.
    Aukner, Ragnhild
    Department of Speech and Language Disorders , Statped sørøst , Oslo , Norway.
    Hide, Øydis
    Department of Speech and Language Disorders , Statped sørøst , Oslo , Norway.
    Feragen, Kristin Billaud
    Department of Speech and Language Disorders , Statped sørøst , Oslo , Norway.
    Rønning, Elisabeth
    Department of Plastic and Reconstructive Surgery , Oslo University Hospital Rikshospitalet , Oslo , Norway.
    Skaare, Pål
    Department of Plastic and Reconstructive Surgery , Oslo University Hospital Rikshospitalet , Oslo , Norway.
    Brinck, Eli
    Department of Plastic and Reconstructive Surgery , Oslo University Hospital Rikshospitalet , Oslo , Norway.
    Semmingsen, Ann-Magritt
    Department of Plastic and Reconstructive Surgery , Oslo University Hospital Rikshospitalet , Oslo , Norway.
    Lindberg, Nina
    Department of Plastic and Reconstructive Surgery , Oslo University Hospital Rikshospitalet , Oslo , Norway.
    Bowden, Melanie
    Greater Manchester Cleft Lip and Palate Unit , Royal Manchester Childrens' Hospital , Manchester , UK.
    Davies, Julie
    Greater Manchester Cleft Lip and Palate Unit , Royal Manchester Childrens' Hospital , Manchester , UK.
    Mooney, Jeanette
    Greater Manchester Cleft Lip and Palate Unit , Royal Manchester Childrens' Hospital , Manchester , UK.
    Bellardie, Haydn
    Greater Manchester Cleft Lip and Palate Unit , Royal Manchester Childrens' Hospital , Manchester , UK.
    Schofield, Nina
    Greater Manchester Cleft Lip and Palate Unit , Royal Manchester Childrens' Hospital , Manchester , UK.
    Nyberg, Jill
    Stockholm Craniofacial Team , Karolinska University Hospital , Stockholm , Sweden.
    Lundberg, Maria
    Stockholm Craniofacial Team , Karolinska University Hospital , Stockholm , Sweden.
    Linder-Aronson Karsten, Agneta
    Stockholm Craniofacial Team, Department of Dental Medicine , Karolinska Institute , Stockholm , Sweden.
    Larson, Margareta
    Eastman Institute, Stockholms Läns Landsting , Stockholm , Sweden.
    Holmefjord, Anders
    Statped vest , Bergen , Norway.
    Reisæter, Sigvor
    Statped vest , Bergen , Norway.
    Pedersen, Nina-Helen
    Statped vest , Bergen , Norway.
    Rasmussen, Therese
    Statped vest , Bergen , Norway.
    Tindlund, Rolf
    Dental School, University of Bergen , Bergen , Norway.
    Sæle, Paul
    Oral Health Center of Expertise/Western Norway , Bergen , Norway.
    Blomhoff, Reidunn
    Centre for Cleft Lip and Palate, Bergen University Hospital Haukeland , Bergen , Norway.
    Jacobsen, Gry
    Centre for Cleft Lip and Palate, Bergen University Hospital Haukeland , Bergen , Norway.
    Havstam, Christina
    Division for Speech and Language Pathology , Sahlgrenska University Hospital , Gothenburg , Sweden.
    Rizell, Sara
    Department of Orthodontics , Sahlgrenska Academy, University of Gothenburg , Sweden.
    Enocson, Lars
    Department of Orthodontics , Sahlgrenska Academy, University of Gothenburg , Sweden.
    Hagberg, Catharina
    Department of Orthodontics , Sahlgrenska Academy, University of Gothenburg , Sweden.
    Najar Chalien, Midia
    Department of Orthodontics , Sahlgrenska Academy, University of Gothenburg , Sweden.
    Paganini, Anna
    Department of Plastic Surgery , Sahlgrenska Academy, University of Gothenburg , Sweden.
    Lundeborg, Inger
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuro and Inflammation Science. Linköping University, Faculty of Medicine and Health Sciences.
    Marcusson, Agneta
    Linköping University, Department of Clinical and Experimental Medicine, Division of Neuro and Inflammation Science. Linköping University, Faculty of Medicine and Health Sciences. Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Maxillofacial Unit.
    Mjönes, Anna-Britta
    Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Department of Otorhinolaryngology in Linköping.
    Gustavsson, Annica
    Region Östergötland, Anaesthetics, Operations and Specialty Surgery Center, Maxillofacial Unit.
    Hayden, Christine
    The Royal Hospital for Sick Children , Belfast , N. Ireland.
    McAleer, Eilish
    The Royal Hospital for Sick Children , Belfast , N. Ireland.
    Slevan, Emma
    The Royal Hospital for Sick Children , Belfast , N. Ireland.
    Gregg, Terry
    The Royal Hospital for Sick Children , Belfast , N. Ireland.
    Worthington, Helen
    Division of Dentistry, University of Manchester , Manchester , UK.
    A Scandcleft randomised trials of primary surgery for unilateral cleft lip and palate: 1. Planning and management.2017In: Journal of Plastic Surgery and Hand Surgery, ISSN 2000-656X, E-ISSN 2000-6764, Vol. 51, no 1, 2-13 p.Article in journal (Refereed)
    Abstract [en]

    BACKGROUND AND AIMS: Longstanding uncertainty surrounds the selection of surgical protocols for the closure of unilateral cleft lip and palate, and randomised trials have only rarely been performed. This paper is an introduction to three randomised trials of primary surgery for children born with complete unilateral cleft lip and palate (UCLP). It presents the protocol developed for the trials in CONSORT format, and describes the management structure that was developed to achieve the long-term engagement and commitment required to complete the project.

    METHOD: Ten established national or regional cleft centres participated. Lip and soft palate closure at 3-4 months, and hard palate closure at 12 months served as a common method in each trial. Trial 1 compared this with hard palate closure at 36 months. Trial 2 compared it with lip closure at 3-4 months and hard and soft palate closure at 12 months. Trial 3 compared it with lip and hard palate closure at 3-4 months and soft palate closure at 12 months. The primary outcomes were speech and dentofacial development, with a series of perioperative and longer-term secondary outcomes.

    RESULTS: Recruitment of 448 infants took place over a 9-year period, with 99.8% subsequent retention at 5 years.

    CONCLUSION: The series of reports that follow this introductory paper include comparisons at age 5 of surgical outcomes, speech outcomes, measures of dentofacial development and appearance, and parental satisfaction. The outcomes recorded and the numbers analysed for each outcome and time point are described in the series.

    TRIAL REGISTRATION: ISRCTN29932826.

  • 43. Morrissey, M.
    et al.
    Hård af Segerstad, Helene
    Linköping University, Faculty of Educational Sciences. Linköping University, Department of Behavioural Sciences, Studies in Adult, Popular and Higher Education.
    A Scandinavian System of Adult Education1993In: Scottish journal of adult education, ISSN 0305-795X, Vol. 1, no 4Article in journal (Other academic)
  • 44.
    Halin, N.
    et al.
    Department of Building, Energy and Environmental Engineering, University of of Gävle, Gävle, Sweden.
    Marsh, J.E.
    Department of Building, Energy and Environmental Engineering, University of of Gävle, Gävle, Sweden; School of Psychology, University of of Central Lancashire, Preston, United Kingdom.
    Hellman, A.
    Department of Building, Energy and Environmental Engineering, University of of Gävle, Gävle, Sweden.
    Hellstrom, I.
    Department of Building, Energy and Environmental Engineering, University of of Gävle, Gävle, Sweden.
    Sörqvist, Patrik
    Linköping University, Department of Behavioural Sciences, Cognition, Development and Disability. Linköping University, Faculty of Arts and Sciences. Department of Building, Energy and Environmental Engineering, University of of Gävle, Gävle, Sweden.
    A shield against distraction2014In: Journal of Applied Research in Memory and Cognition, ISSN 2211-3681, Vol. 3, no 1, 31-36 p.Article in journal (Refereed)
    Abstract [en]

    In this paper, we apply the basic idea of a trade-off between the level of concentration and distractibility to test whether a manipulation of task difficulty can shield against distraction. Participants read, either in quiet or with a speech noise background, texts that were displayed either in an easy-to-read or a hard-to-read font. Background speech impaired prose recall, but only when the text was displayed in the easy-to-read font. Most importantly, recall was better in the background speech condition for hard-to-read than for easy-to-read texts. Moreover, individual differences in working memory capacity were related to the magnitude of disruption, but only in the easy-to-read condition. Making a task more difficult can sometimes facilitate selective attention in noisy work environments by promoting focal-task engagement. © 2014 The Authors.

  • 45.
    Ejlali, Alireza
    et al.
    Sharif University of Technology.
    Al-Hashimi, Bashir
    University of Southampton.
    Eles, Petru
    Linköping University, Department of Computer and Information Science, ESLAB - Embedded Systems Laboratory. Linköping University, The Institute of Technology.
    A Standby-Sparing Technique with Low Energy-Overhead for Fault-Tolerant Hard Real-Time Systems2009In: Intl. Conference on Hardware-Software Co-Design and System Synthesis (CODES/ISSS), Grenoble, France, October 11-16, 2009 (best paper award)., 2009, 193-202 p.Conference paper (Refereed)
    Abstract [en]

    Time redundancy (rollback-recovery) and hardware redundancy are commonly used in real-time systems to achieve fault tolerance. From an energy consumption point of view, time redundancy is generally more preferable than hardware redundancy. However, hard real-time systems often use hardware redundancy to meet high reliability requirements of safety-critical applications. In this paper we propose a hardware-redundancy technique with low energy-overhead for hard real-time systems. The proposed technique is based on standby-sparing, where the system is composed of a primary unit and a spare. Through analytical models, we have developed an online energy-management method which uses a slack reclamation scheme to reduce the energy consumption of both the primary and spare units. In this method, dynamic voltage scaling (DVS) is used for the primary unit and dynamic power management (DPM) is used for the spare. We conducted several experiments to compare the proposed system with a fault-tolerant real-time system which uses time redundancy for fault tolerance and DVS with slack reclamation for low energy consumption. The results show that for relaxed time constraints, the proposed system provides up to 24% energy saving as compared to the time-redundancy system. For tight deadlines when the time-redundancy system can tolerate no faults, the proposed system preserves its fault-tolerance but with about 32% more energy consumption.

  • 46.
    Wallin, Ragnar
    et al.
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    Hansson, Anders
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    Harju Johansson, Janne
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    A Structure Exploiting Preprocessor for Semidefinite Programs Derived From the Kalman-Yakubovich-Popov Lemma2009In: IEEE Transactions on Automatic Control, ISSN 0018-9286, E-ISSN 1558-2523, Vol. 54, no 4, 697-704 p.Article in journal (Refereed)
    Abstract [en]

    Semidefinite programs derived from the Kalman-Yakubovich-Popov (KYP) lemma are quite common in control and signal processing applications. The programs are often of high dimension which makes them hard or impossible to solve with general-purpose solvers. Here we present a customized preprocessor, KYPD, that utilizes the inherent structure of this particular optimization problem. The key to an efficient implementation is to transform the optimization problem into an equivalent semidefinite program. This equivalent problem has much fewer variables and the matrices in the linear matrix inequality constraints are of low rank. KYPD can use any primal-dual solver for semidefinite programs as an underlying solver.

  • 47.
    Eriksson, Björn
    Linköping University, Department of Computer and Information Science, Software and Systems.
    A study of Bitcoin as a currency for email-based micro-transactions2016Independent thesis Basic level (degree of Bachelor), 10,5 credits / 16 HE creditsStudent thesis
    Abstract [en]

    Bitcoin is a cryptocurrency that has been the focus of a lot of discussions lately and has attracted a large number of users. Its offers many possibilities for cheap transactions and unregulated finances which has been realized in numerous sites and applications on the web and in mobile phones. One medium that seem to have been neglected when it comes to Bitcoins development is email. This is curious since Bitcoin by its nature seem to have many properties that would work well with texted messages. The purpose of this study it to analyze the current papers about Bitcoin to find the current status of email based Bitcoin services,  and try to analyze if email as a tool is a suitable medium to be used with Bitcoin. This analyze is done through a systematic literature review of current papers, followed by an examination of past and current Bitcoin companies that has used email as part of their service. In the end the results suggested that the low security in email, and the apparent lack of services that would benefit from an email based Bitcoin service suggest that a service like that would be hard to develop today and not very useful to the public.

  • 48.
    Ledent-Semple, Elisabeth
    Linköping University, Department of health and environment. Linköping University, Department of Biomedicine and Surgery. Linköping University, Faculty of Health Sciences.
    A study of factors influencing the quality of blood products during preparation, storage and filtration2001Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The quality of a cell concentrate to be transfused is dependent on the method of preparation and the storage conditions of the blood products. The aim of this study was to determine, compare and evaluate factors influencing the quality of platelet and erythrocyte concentrates. The influence of the method of preparation on platelet concentrates from whole blood and on leukocyte depletion by filtration of erythrocyte concentrates was studied. In addition, the influence of storage on leukocyte depletion by filtration of platelet and erythrocyte concentrates was investigated.

    The method of preparation of platelet concentrates from whole blood influenced the release from the platelet α-granules. A significant increase in the release was found in the concentrates prepared from platelet-rich plasma compared with buffy coat. If the buffy coat was allowed to rest for <4 hours before centrifugation, this difference was significant until day 3 of storage. The ability of platelets to stimulate the growth of fibroblasts followed a similar course and decreased during preparation and storage.

    The method of preparation of erythrocyte concentrates was shown to influence the outcome of leukocyte depletion by filtration. When hard spun, buffy coat depleted, concentrates were used, the number of leukocytes found in the filtrate was significantly higher compared with units that had been supplemented with an additional 5 or 10 ml of plasma. The flow rate during filtration and temperature of the unit was also shown to have an influence on the outcome on the number of leukocytes post filtration.

    The storage time of both erythrocyte and platelet concentrates resulted in significant differences in the number ofleukocytes found after leukocyte depletion by filtration. A short storage time of erythrocyte concentrates was found to give a higher number of leukocytes after filtration compared with a longer storage time. This was in contrast to platelet concentrates where a filtration just after preparation, i.e. no storage time, gave better leukocyte depletion compared with 5 days of storage.

    The distribution ofleukocyte subsets was also changed significantly by filtration. Comparing the pre- and post-filtration percentages of subsets in platelet concentrates, we found a lower percentage of T-lymphocytes and a higher percentage of B-lymphocytes and monocytes post filtration. In conclusion, the method of preparation of cell concentrates and the storage time have a substantial impact on the properties of the final product. Standardized and controlled procedures are of great importance in making optimal blood products.

    List of papers
    1. Growth Factor Release during Preparation and Storage of Platelet Concentrates
    Open this publication in new window or tab >>Growth Factor Release during Preparation and Storage of Platelet Concentrates
    1995 (English)In: Vox Sanguinis, ISSN 0042-9007, E-ISSN 1423-0410, Vol. 68, no 4, 205-209 p.Article in journal (Refereed) Published
    Abstract [en]

    The platelet content of platelet-derived growth factor (PDGF), a mitogen stored in the alpha-granules, was studied during preparation and storage of platelet concentrates (PC) and compared to the growth-promoting activity of platelets, β-thromboglobulin (β-TG) and lactate dehydrogenase (LD). We compared PC prepared from platelet-rich plasma (PRP-PC; n= 10) and from buffy coat. Two different pre-preparation storage periods of the buffy coat were used: 4h (BC-PC:4h; n = 10) and 24 h (BC-PC: 24h; n = 5). The platelet content of PDGF and β-TG was measured by a RIA technique and the growth-promoting activity by incorporation of 3H-thymidine in stimulated fibroblasts. The platelet content of PDGF, β-TG and the growth-promoting activity of the platelets decreased in a similar way during preparation and storage of PRP-PC (31 ±2, 35±2 and 33±7%, respectively, at day 5 of storage; mean ± SEM). The release of LD was minor (3.9 ±0.5% at day 5). At day 1 of storage the platelet content of PDGF was significantly better preserved in BC-PC:4h than in BD-PC:24h (88±2 and 81 ±3%, respectively; p = 0.03). Comparing BC-PC:4h and PRP-PC we found a significantly better preservation of PDGF in BC-PC:4h until day 3 of storage (80±2 and 75±1%, respectively at day 3; p = 0.046). In conclusion the preparation of PC according to the PRP method initially induces a higher loss of PDGF, and hence of the growth-promoting activity, than the BC method.

    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-81056 (URN)10.1111/j.1423-0410.1995.tb02573.x (DOI)
    Available from: 2012-09-06 Created: 2012-09-06 Last updated: 2012-09-06Bibliographically approved
    2. Inadequate white cell reduction by bedside filtration of red cell concentrates
    Open this publication in new window or tab >>Inadequate white cell reduction by bedside filtration of red cell concentrates
    1994 (English)In: Transfusion, ISSN 0041-1132, E-ISSN 1537-2995, Vol. 34, no 9, 765-768 p.Article in journal (Refereed) Published
    Abstract [en]

    Background: White cell filtration of red cell concentrates is often performed at the bedside, in the ward, with the filter inserted in the blood administration line. The aim of this study was to evaluate the efficiency of this filtration method and compare it to filtration in the blood bank.

    Study Design and Methods: One-day-old, buffy coat-reduced, hard-packed red cell concentrates in saline-adenine-glucose-mannitol solution were filtered through different filters designed for bedside or laboratory use. With filters designed for bedside use, filtration of red cells was performed under laboratory conditions at fast flow (10 min) or under bedside conditions at slow flow (2 hours). The remaining white cells were counted microscopically. Filters designed for laboratory use were evaluated at fast flow, and the number of contaminating white cells was counted by flow cytometry.

    Results: With bedside fllters, a significantly higher contamination of white cells was found In the units filtered at slow flow than at fast flow, regardless of the filter used. The number of units with >5 x 106 white cells was 52 (78%) of 67 filtered at slow flow compared to 11 (23%) of 47 at fast flow, all filters taken together. This difference in white cell contamination was mainly due to an increase of polymorphonuclear cells in the red cell concentrates filtered at slow flow. With filters designed for laboratory use, 0 to 2 percent of units (n = 1448) were contaminated with >5 x 106 white cells.

    Conclusion: Bedside filtration for white cell reduction at slow flow is inefficient for 1-day-old, buffy coat-reduced red cell concentrates.

    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-81057 (URN)10.1046/j.1537-2995.1994.34994378276.x (DOI)
    Available from: 2012-09-06 Created: 2012-09-06 Last updated: 2012-09-06Bibliographically approved
    3. Factors influencing white cell removal from red cell concentrates by filtration
    Open this publication in new window or tab >>Factors influencing white cell removal from red cell concentrates by filtration
    1996 (English)In: Transfusion, ISSN 0041-1132, E-ISSN 1537-2995, Vol. 36, no 8, 714-718 p.Article in journal (Refereed) Published
    Abstract [en]

    BACKGROUND: The preparation of blood components by hard centrifugation results in red cell concentrates with a small amount of plasma. The influence of various plasma factors, temperature, and storage time on white cell reduction by filtration was studied. STUDY

    DESIGN AND METHODS: Red cell concentrates were suspended in 100 mL of saline- adenine-glucose-mannitol (SAGMAN) solution or in SAGMAN solution in which 5 or 10 mL had been replaced with an equal amount of fresh plasma, albumin (4%), or heat-inactivated plasma. After overnight storage at 4 degrees C, filtration at a slow flow rate (2 hours) was performed. The effect of temperature was studied by filtration at 4 degrees C and 37 degrees C. To study the influence of storage time, red cell concentrates were stored for 4 to 8 hours or 14 to 20 hours at 4 degrees C and filtered through another model of filter. The number of white cells was counted microscopically or by flow cytometry.

    RESULTS: When 5 or 10 mL of plasma was added, a significantly smaller number of white cells were found after filtration than were found in the SAGMAN control (the median difference between pairs: 23.6 × 10(6) for 5 mL [p = 0.006] and 14.9 × 10(6) for 10 mL [p = 0.003]). The number of white cells was significantly higher with 10 mL of albumin than with 10 mL of plasma (difference, 15.0 × 10(6); p = 0.006). When heat-inactivated plasma was used, the number of white cells was significantly lower than when fresh plasma was used (difference, 0.3 × 10(6); p = 0.009). Filtration at 37 degrees C resulted in a 64-percent reduction in white cells and that at 4 degrees C led to a 99.7-percent reduction (p = 0.006). When the second filter was used, a slight but significantly lower number of white cells was found in the red cell concentrate stored for 14 to 20 hours than in that stored for 4 to 8 hours (difference, 0.03 × 10(6); p < 0.001).

    CONCLUSION: The amount of plasma in the red cell concentrate and the storage time and temperature are important factors in the outcome of white cell reduction by filtration. The effect of plasma does not seem to be due to a general influence of protein or to the activity of complement or fibrinogen.

    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-81058 (URN)10.1046/j.1537-2995.1996.36896374375.x (DOI)
    Available from: 2012-09-06 Created: 2012-09-06 Last updated: 2012-09-06Bibliographically approved
    4. White Blood Cell Subsets in Buffy Coat-Derived Platelet Concentrates: The Effect of Pre- and Poststorage Filtration
    Open this publication in new window or tab >>White Blood Cell Subsets in Buffy Coat-Derived Platelet Concentrates: The Effect of Pre- and Poststorage Filtration
    2000 (English)In: Vox Sanguinis, ISSN 0042-9007, E-ISSN 1423-0410, Vol. 79, no 4, 235-241 p.Article in journal (Refereed) Published
    Abstract [en]

    Background and Objectives: Our objective was to study the effect of storage time on the filtration of platelet concentrates (PCs). We compared the total number of white blood cells (WBC), as well as the distribution of WBC subsets, in units filtered before and after storage.

    Materials and Methods: Buffy coat-derived PCs were filtered either fresh or after 5 days of storage, and total WBC were enumerated by flow cytometry. WBC subsets were analyzed by flow cytometry with three-color fluorescence.

    Results: The total number of white cells before filtration was significantly higher in fresh units compared with stored units, whereas in postfiltration samples the number of white cells was significantly lower in the fresh compared with the stored units. Although absolute numbers were significantly reduced, filtration also induced significant changes in the proportions of subsets in both fresh and stored units; the percentage of T cells was decreased, whereas the percentage of B cells and monocytes was increased after filtration.

    Conclusion: Our results suggest that prestorage WBC filtration of platelet concentrates is superior in reducing the absolute numbers of WBC. However, both pre- and poststorage WBC filtration significantly affect the proportions of WBC in the final product, decreasing the number of T cells while apparently increasing the proportion of MHC class II-positive cell populations.

    National Category
    Medical and Health Sciences
    Identifiers
    urn:nbn:se:liu:diva-25802 (URN)10.1159/000056737 (DOI)10239 (Local ID)10239 (Archive number)10239 (OAI)
    Available from: 2009-10-08 Created: 2009-10-08 Last updated: 2012-09-06Bibliographically approved
  • 49.
    Byers, David
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Computer and Information Science, Database and information techniques.
    Shahmehri, Nahid
    Linköping University, Department of Computer and Information Science, Database and information techniques. Linköping University, The Institute of Technology.
    A systematic evaluation of disk imaging in EnCase® 6.8 and LinEn 6.12009In: Digital Investigation, ISSN 1742-2876, Vol. 6, no 1-2, 61-70 p.Article in journal (Refereed)
    Abstract [en]

    Tools for disk imaging (or more generally speaking, digital acquisition) are a foundation for forensic examination of digital evidence. Therefore it is crucial that such tools work as expected. The only way to determine whether this is the case or not is through systematic testing of each tool. In this paper we present such an evaluation of the disk imaging functions of EnCase 6.8® and LinEn 6.1, conducted on behalf of the Swedish National Laboratory of Forensic Science. Although both tools performed as expected under most circumstances, we identified cases where flaws that can lead to inaccurate and incomplete acquisition results in LinEn 6.1 were exposed. We have also identified limitations in the tool that were not evident from its documentation. In addition summarizing the test results, we present our testing methodology, which has novel elements that we think can benefit other evaluation projects.

  • 50.
    Alling, Björn
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Högberg, Hans
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Armiento, Rickard
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, Faculty of Science & Engineering.
    Rosén, Johanna
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    A theoretical investigation of mixing thermodynamics, age-hardening potential, and electronic structure of ternary (M1-xMxB2)-M-1-B-2 alloys with AlB2 type structure2015In: Scientific Reports, ISSN 2045-2322, Vol. 5Article in journal (Refereed)
    Abstract [en]

    Transition metal diborides are ceramic materials with potential applications as hard protective thin films and electrical contact materials. We investigate the possibility to obtain age hardening through isostructural clustering, including spinodal decomposition, or ordering-induced precipitation in ternary diboride alloys. By means of first-principles mixing thermodynamics calculations, 45 ternary (M1-xMxB2)-M-1-B-2 alloys comprising (MB2)-B-i (M-i = Mg, Al, Sc, Y, Ti, Zr, Hf, V, Nb, Ta) with AlB2 type structure are studied. In particular Al1-xTixB2 is found to be of interest for coherent isostructural decomposition with a strong driving force for phase separation, while having almost concentration independent a and c lattice parameters. The results are explained by revealing the nature of the electronic structure in these alloys, and in particular, the origin of the pseudogap at E-F in TiB2, ZrB2, and HfB2.

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