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  • 1.
    Asghar, Rizwan
    et al.
    Linköping University, Department of Electrical Engineering, Computer Engineering. Linköping University, The Institute of Technology.
    Liu, Dake
    Linköping University, Department of Electrical Engineering, Computer Engineering. Linköping University, The Institute of Technology.
    2-D Realization of WiMAX Channel Interleaver for Efficient Hardware Implementation2009In: Proceedings of World Academy of Science, Engineering and Technology (ISSN: 2070-3740), 2009, 25-29 p.Conference paper (Refereed)
    Abstract [en]

    The direct implementation of interleaver functions in WiMAX is not hardware efficient due to presence of complex functions. Also the conventional method i.e. using memories for storing the permutation tables is silicon consuming. This work presents a 2-D transformation for WiMAX channel interleaver functions which reduces the overall hardware complexity to compute the interleaver addresses on the fly.  A fully re-configurable architecture for address generation in WiMAX channel interleaver is presented, which consume 1.1 k-gates in total. It can be configured for any block size and any modulation scheme in WiMAX. The presented architecture can run at a frequency of 200 MHz, thus fully supporting high bandwidth requirements for WiMAX.

  • 2.
    Grönwall, Christina
    et al.
    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.
    3D Content-Based Model Matching using Geometric Features2006Report (Other academic)
    Abstract [en]

    We present an approach that utilizes efficient geometric feature extraction and a matching method that takes articulation into account. It is primarily applicable for man-made objects. First the object is analyzed to extract geometric features, dimensions and rotation are estimated and typical parts, so-called functional parts, are identified. Examples of functional parts are a box's lid, a building's chimney, or a battle tank's barrel. We assume a model library with full annotation. The geometric features are matched with the model descriptors, to gain fast and early rejection of non-relevant models. After this pruning the objectis matched with relevant, usually few, library models. We propose a sequential matching, where the number of functional parts increases in each iteration. The division into parts increases the possibility for correct matching result when several similar models are available. The approach is exemplifi…ed with an vehicle recognition application, where some vehicles have functional parts.

  • 3.
    Wikström, Jonas
    Linköping University, Department of Management and Engineering, Machine Design.
    3D Model of Fuel Tank for System Simulation: A methodology for combining CAD models with simulation tools2011Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Engineering aircraft systems is a complex task. Therefore models and computer simulations are needed to test functions and behaviors of non existing systems, reduce testing time and cost, reduce the risk involved and to detect problems early which reduce the amount of implementation errors. At the section Vehicle Simulation and Thermal Analysis at Saab Aeronautics in Linköping every basic aircraft system is designed and simulated, for example the fuel system. Currently 2-dimensional rectangular blocks are used in the simulation model to represent the fuel tanks. However, this is too simplistic to allow a more detailed analysis. The model needs to be extended with a more complex description of the tank geometry in order to get a more accurate model.

    This report explains the different steps in the developed methodology for combining 3-dimensional geometry models of any fuel tank created in CATIA with dynamic simulation of the fuel system in Dymola. The new 3-dimensional representation of the tank in Dymola should be able to calculate fuel surface location during simulation of a maneuvering aircraft. 

    The first step of the methodology is to create a solid model of the fuel contents in the tank. Then the area of validity for the model has to be specified, in this step all possible orientations of the fuel acceleration vector within the area of validity is generated. All these orientations are used in the automated volume analysis in CATIA. For each orientation CATIA splits the fuel body in a specified number of volumes and records the volume, the location of the fuel surface and the location of the center of gravity. This recorded data is then approximated with the use of radial basis functions implemented in MATLAB. In MATLAB a surrogate model is created which are then implemented in Dymola. In this way any fuel surface location and center of gravity can be calculated in an efficient way based on the orientation of the fuel acceleration vector and the amount of fuel.

    The new 3-dimensional tank model is simulated in Dymola and the results are compared with measures from the model in CATIA and with the results from the simulation of the old 2-dimensional tank model. The results shows that the 3-dimensional tank gives a better approximation of reality and that there is a big improvement compared with the 2-dimensional tank model. The downside is that it takes approximately 24 hours to develop this model.

  • 4.
    Johansson, Victor
    Linköping University, Department of Electrical Engineering, Computer Vision. Linköping University, The Institute of Technology.
    3D Position Estimation of a Person of Interest in Multiple Video Sequences: Person of Interest Recognition2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Because of the increase in the number of security cameras, there is more video footage available than a human could efficiently process. In combination with the fact that computers are getting more efficient, it is getting more and more interesting to solve the problem of detecting and recognizing people automatically.

    Therefore a method is proposed for estimating a 3D-path of a person of interest in multiple, non overlapping, monocular cameras. This project is a collaboration between two master theses. This thesis will focus on recognizing a person of interest from several possible candidates, as well as estimating the 3D-position of a person and providing a graphical user interface for the system. The recognition of the person of interest includes keeping track of said person frame by frame, and identifying said person in video sequences where the person of interest has not been seen before.

    The final product is able to both detect and recognize people in video, as well as estimating their 3D-position relative to the camera. The product is modular and any part can be improved or changed completely, without changing the rest of the product. This results in a highly versatile product which can be tailored for any given situation.

  • 5.
    Lång, Magnus
    Linköping University, The Institute of Technology. Linköping University, Department of Science and Technology.
    3D Teleconferencing: The construction of a fully functional, novel 3D Teleconferencing system2009Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This report summarizes the work done to develop a 3D teleconferencing system, which enables remote participants anywhere in the world to be scanned in 3D, transmitted and displayed on a constructed 3D display with correct vertical and horizontal parallax, correct eye contact and eye gaze. The main focus of this report is the development of this system and especially how to in an efficient and general manner render to the novel 3D display. The 3D display is built out of modified commodity hardware and show a 3D scene for observers in up to 360 degrees around it and all heights. The result is a fully working 3D Teleconferencing system, resembling communication envisioned in movies such as holograms from Star Wars. The system transmits over the internet, at similar bandwidth requirements as concurrent 2D videoconferencing systems.

  • 6.
    Andersson, Tim
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Lind, Kristoffer
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    3D-visualization of residential buildings in Manstorp2007Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In real estate ads in both newspapers and on the Internet, there are more and more computer modeled houses for sale. We believe that this is one of the biggest markets for visualization today. When time and technology are ready, we expect that visualization will be used a lot more to create projects where people can “trust” in what is being visualized. For our final thesis we wanted to work with

    Visualization, our concentration within the Construction Engineering program at Linköping University. We managed to do this with the construction company Peab in Linköping, who wanted to make their marketing of their project Manstorp in Linghem more efficient. The pictures that the hired architect firm used to visualize the property with were not sufficient enough, according to Peab, in giving the true picture of the area. The goal for our thesis was to create more realistic and living images, and thereby help Peab sell all of the real estates before completing the constructions.

    We were continuously given material from Peab and the architect firm White in order to visualize a realistic set of pictures for potential clients. One of computer visualizations biggest advantages is that it is easy to modify the models according to changes in the material given. Compared to classic design methods such as hand-drawn sketches, physical models and computer manipulated pictures it was easy for us to change features such as color, displacement and size. We wanted to show how the cooperation between people who visualizes, construction companies and architects could work, where problems could evolve and which solutions and methods are to be preferred.

    The goal was to create a model of the exterior and interior of the individual buildings in their final environment and display this with pictures on Peab’s and the real estate agent’s website. We achieved this goal and the result can be seen at:

    http://www.peab.se/Bostader_lokaler/Bostader/ostergotland/Linkoping/Manstorp

  • 7.
    Sanjuan, Joseba
    Linköping University, Department of Computer and Information Science. Linköping University, The Institute of Technology.
    3G Energy-Efficient Packet Handling Kernel Module for Android2012Independent thesis Advanced level (degree of Master (Two Years)), 30 credits / 45 HE creditsStudent thesis
    Abstract [en]

    The use of mobile devices is increasing due to the constant development of more advanced and appealing applications and computing features. However, these new features are very power hungry leading to short battery lifetimes. Research shows that a major reason for fast battery depletion is the excessive and inefficient use of the wireless interfaces. This thesis studies how we can attempt to increase the battery lifetime of the devices without having to sacrifice the usage of these advanced features in some applications.

    The thesis focuses on adapting the traffic pattern characteristics of mobile communication using a widespread wireless communication technology like 3G. Traffic pattern adaptation is performed at packet level in kernel space in Android. The data transfers are scheduled with the knowledge of the energy consumption characteristics of 3G. The performed measurements indicate that our solution can provide energy savings ranging from 7% to 59%.

    This work confirms that 3G conscious scheduling of network traffic reduces energy consumption, and that, both applications and energy saving libraries are potential directions to be further studied.

  • 8.
    Säll, Erik
    et al.
    Linköping University, Department of Electrical Engineering.
    Vesterbacka, Mark
    Linköping University, Department of Electrical Engineering. Linköping University, Department of Electrical Engineering, Electronics System.
    6 bit 1 GHz CMOS silicon-on-insulator flash analog-to-digital converter for read channel applications2005In: Proc. European Conf. on Circuit Theory and Design, ECCTD'05, 2005, I/127-I/130 p.Conference paper (Refereed)
    Abstract [en]

    The purpose of this work is to investigate the possibility to implement analog base band circuitry along with digital circuitry in silicon-on-insulator technology. Hence a 6 bit Nyquist rate flash analog-to-digital converter is designed in a 130 nm CMOS silicon-on-insulator technology. The converter is aimed for read channel or ultra-wideband radio applications. The simulations indicate a 170 mW power consumption at a maximum sampling rate of 1 GHz. The supply voltage is only 1.2 V. The effective number of bit is 5.8 bit and the effective resolution bandwidth is 390 MHz. An energy per conversion step of 3.9 pJ indicate that this converter is as efficient as other state-of-the-art converters, without using interpolation or averaging techniques.

  • 9.
    Fazli Yeknami, Ali
    et al.
    Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
    Alvandpour, Atila
    Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
    A 0.5-V 250-nW 65-dB SNDR Passive ΔΣ Modulator for Medical Implant Devices2013In: Proceedings of the IEEE International Symposium on Circuits and Systems (ISCAS), Beijing, China, 19-23 May, 2013, 2013, 2010-2013 p.Conference paper (Refereed)
    Abstract [en]

    A  0.5-V  ultra-low-power  second-order  DT  DS  modulator  is  presented  in  this  paper  for  medical  implant  devices.  The  modulator  employs  2nd-order  passive  low-pass filter  and  ultra-low-voltage  building  blocks,  including preamplifier, regenerative comparator, and clock controller, in order  to enable operation near 0.5 V supply. A  low-noise and gain-enhanced  single-stage  preamplifier  is  developed  using  a body-driven technique. Passive filter is gain boosted by power-efficient charge-redistribution amplification  scheme. Designed in  a  65nm CMOS  technology,  the modulator  achieves  65  dB peak SNDR over a 500 Hz signal bandwidth, while it consumes 250 nW  from  a  0.5 V  supply. The modulator  is  functional  at 0.45V and obtains 52 dB SNR, while consuming 200 nW.

  • 10.
    Fazli Yeknami, Ali
    et al.
    Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
    Alvandpour, Atila
    Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
    A 0.7-V 400-nW Fourth-Order Active-Passive Delta-Sigma Modulator with One Active Stage2013Conference paper (Refereed)
    Abstract [en]

    A 0.7 V 400 nW fourth-order active-passive ΔΣ modulator with one active stage is presented in this paper using standard CMOS 65 nm technology. The modulator achieves 84 dB SNR and 80.3 dB SNDR in a signal bandwidth of 500 Hz with a sampling frequency of 256 kHz. The input-feedforward architecture is used to improve the voltage swing before the comparator of the traditional passive modulators, which enables simpler comparator design with no preamplifier as well as cascading three successive power-efficient passive filters. The first active stage is used to reduce the comparator's noise and offset and to minimize the capacitive area. The modulator achieves a high power-efficiency (47 fJ/step) in terms of widely used figure of merit.

  • 11.
    Yeknami, Ali Fazli
    et al.
    Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
    Alvandpour, Atila
    Linköping University, Department of Electrical Engineering, Electronic Devices. Linköping University, The Institute of Technology.
    A 2.1 uW 76 dB SNDR DT-ΔΣ Modulator for Medical Implant Devices2012In: NORCHIP 2012, IEEE , 2012, 1-4 p.Conference paper (Refereed)
    Abstract [en]

    This paper presents a low-power 2nd-order discrete-time (DT) ΔΣ analog-to-digital converter (ADC) aimed for medical implant devices. The designed ΔΣ modulator with two active integrators (filters) employs power-efficient two-stage load-compensated OTAs with minimal load and rail-to-rail output swing, which provides higher power-efficiency than the two-stage Miller OTA. The modulator, implemented in a 65nm CMOS technology with a core area of 0.033 mm2, achieves 76-dB peak SNDR over a 500 Hz signal bandwidth, while consuming 2.1 µW from a 0.9 V supply voltage. Compared to previously reported modulators for such signal bandwidths, the achieved performance (FOM of 0.4 pJ/step) make the presented modulator one of the best among sub-1-V modulators in term of most commonly used figure of merit.

  • 12.
    Eriksson, Henrik
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Electrical Engineering, Electronic Devices.
    Larsson-Edefors, Per
    Chalmers.
    Alvandpour, Atila
    Linköping University, The Institute of Technology. Linköping University, Department of Electrical Engineering, Electronic Devices.
    A 2.8 ns 30 uW/MHz area-efficient 32-b Manchester carry-bypass adder.2001In: IEEE International Symposium on Circuits and Systems ISCAS.,2001, Piscataway: IEEE , 2001, Vol. 4, 84-87 p.Conference paper (Refereed)
    Abstract [en]

    A fast and area-efficient 32-b Manchester carry-bypass adder with low energy-delay product is presented in this paper. The high speed is achieved by the use of optimized bypass circuitry and fast repeater elements in the carry path. The fabricated adder has a measured worst-case delay of 2.8 ns and consumes 30 μW/MHz

  • 13.
    Braian, Clara
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences.
    Svensson, Mattias
    Karolinska Institute, Sweden.
    Brighenti, Susanna
    Karolinska Institute, Sweden.
    Lerm, Maria
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences.
    Parasa, Venkata R.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Microbiology and Molecular Medicine. Linköping University, Faculty of Medicine and Health Sciences. Karolinska Institute, Sweden.
    A 3D Human Lung Tissue Model for Functional Studies on Mycobacterium tuberculosis Infection2015In: Journal of Visualized Experiments, ISSN 1940-087X, E-ISSN 1940-087X, no 104, 1-9 p., e53084Article in journal (Refereed)
    Abstract [en]

    Tuberculosis (TB) still holds a major threat to the health of people worldwide, and there is a need for cost-efficient but reliable models to help us understand the disease mechanisms and advance the discoveries of new treatment options. In vitro cell cultures of monolayers or co-cultures lack the three-dimensional (3D) environment and tissue responses. Herein, we describe an innovative in vitro model of a human lung tissue, which holds promise to be an effective tool for studying the complex events that occur during infection with Mycobacterium tuberculosis (M. tuberculosis). The 3D tissue model consists of tissue-specific epithelial cells and fibroblasts, which are cultured in a matrix of collagen on top of a porous membrane. Upon air exposure, the epithelial cells stratify and secrete mucus at the apical side. By introducing human primary macrophages infected with M. tuberculosis to the tissue model, we have shown that immune cells migrate into the infected-tissue and form early stages of TB granuloma. These structures recapitulate the distinct feature of human TB, the granuloma, which is fundamentally different or not commonly observed in widely used experimental animal models. This organotypic culture method enables the 3D visualization and robust quantitative analysis that provides pivotal information on spatial and temporal features of host cell-pathogen interactions. Taken together, the lung tissue model provides a physiologically relevant tissue micro-environment for studies on TB. Thus, the lung tissue model has potential implications for both basic mechanistic and applied studies. Importantly, the model allows addition or manipulation of individual cell types, which thereby widens its use for modelling a variety of infectious diseases that affect the lungs.

  • 14.
    Garrido Gálvez, Mario
    et al.
    Linköping University, Department of Electrical Engineering, Computer Engineering. Linköping University, Faculty of Science & Engineering.
    Angel Sanchez, Miguel
    University of Politecn Madrid, Spain.
    Luisa Lopez-Vallejo, Maria
    University of Politecn Madrid, Spain.
    Grajal, Jesus
    University of Politecn Madrid, Spain.
    A 4096-Point Radix-4 Memory-Based FFT Using DSP Slices2017In: IEEE Transactions on Very Large Scale Integration (vlsi) Systems, ISSN 1063-8210, E-ISSN 1557-9999, Vol. 25, no 1, 375-379 p.Article in journal (Refereed)
    Abstract [en]

    This brief presents a novel 4096-point radix-4 memory-based fast Fourier transform (FFT). The proposed architecture follows a conflict-free strategy that only requires a total memory of size N and a few additional multiplexers. The control is also simple, as it is generated directly from the bits of a counter. Apart from the low complexity, the FFT has been implemented on a Virtex-5 field programmable gate array (FPGA) using DSP slices. The goal has been to reduce the use of distributed logic, which is scarce in the target FPGA. With this purpose, most of the hardware has been implemented in DSP48E. As a result, the proposed FPGA is efficient in terms of hardware resources, as is shown by the experimental results.

  • 15.
    Ahmed, Tanvir
    et al.
    Linköping University, Department of Electrical Engineering. Linköping University, Faculty of Science & Engineering.
    Garrido, Mario
    Linköping University, Department of Electrical Engineering, Electronics System. Linköping University, The Institute of Technology.
    Gustafsson, Oscar
    Linköping University, Department of Electrical Engineering, Electronics System. Linköping University, The Institute of Technology.
    A 512-point 8-parallel pipelined feedforward FFT for WPAN2011In: 2011 Conference Record of the Forty Fifth Asilomar Conference on Signals, Systems and Computers (ASILOMAR), IEEE , 2011, 981-984 p.Conference paper (Refereed)
    Abstract [en]

    This paper presents a 512-point feedforward FFT architecture for wireless personal area network (WPAN). The architecture processes a continuous flow of 8 samples in parallel, leading to a throughput of 2.64 GSamples/s. The FFT is computed in three stages that use radix-8 butterflies. This radix reduces significantly the number of rotators with respect to previous approaches based on radix-2. Besides, the proposed architecture uses the minimum memory that is required for a 512-point 8-parallel FFT. Experimental results show that besides its high throughput, the design is efficient in area and power consumption, improving the results of previous approaches. Specifically, for a wordlength of 16 bits, the proposed design consumes 61.5 mW and its area is 1.43 mm2.

  • 16.
    Aamir, Syed Ahmed
    Linköping University. Linköping University, Department of Electrical Engineering.
    A 65nm, Low Voltage, Fully Differential, SC Programmable Gain Amplifier for Video AFE2010Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Due to rapid growth of home entertainment consumer market, video technology has been continuously pushed to deliver sharper pictures with higher resolution. This has brought about stringent requirements on the video analog front end, which often coupled with the low power and low voltage regulations had to deal with short channel effects of the deep submicron CMOS processes.

    This thesis presents the design of a fully differential programmable gain amplifier, as a subcircuit of a larger video digitizing IC designed at division of Electronic Systems. The switched capacitor architecture of the PGA does not only buffer the signal, but performs compensation for the sync-tip of analog video signal.

    The pseudo differential OTA eliminates tail current source and maintains high signal swing and has efficient common mode feedforward mechanism. When coupled with a similar stage provides inherent common moode feedback without using an additional SC-CMFB block.

    The PGA has been implemented using a 65 nm digital CMOS process. Expected difficulties in a 1.2 V OTA design make themselves evident in 65 nm, which is why cascaded OTA structures were inevitable for attaining gain specification of 60 dB. Nested Miller compensation with a pole shifting source follower, stabilizes the multipole system. The final circuit attains up to 200 MHz bandwidth and maintains high output swing of 0.85 V. High slew rate and good common mode and power supply rejection are observed. Noise requirements require careful design of input differential stage. Although output source follower stabilized the system, it reduces significant bandwidth and adds to second order non-linearity.

  • 17.
    Eklund, Anders
    et al.
    Linköping University, Department of Computer and Information Science, Statistics. Linköping University, Department of Biomedical Engineering, Division of Biomedical Engineering. Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Faculty of Science & Engineering. Linköping University, Faculty of Arts and Sciences.
    Lindqvist, Martin A
    Department of Biostatistics, Johns Hopkins University, Baltimore, USA.
    Villani, Mattias
    Linköping University, Department of Computer and Information Science, Statistics. Linköping University, Faculty of Arts and Sciences.
    A Bayesian Heteroscedastic GLM with Application to fMRI Data with Motion Spikes2017In: NeuroImage, ISSN 1053-8119, E-ISSN 1095-9572, Vol. 155, 354-369 p.Article in journal (Refereed)
    Abstract [en]

    We propose a voxel-wise general linear model with autoregressive noise and heteroscedastic noise innovations (GLMH) for analyzing functional magnetic resonance imaging (fMRI) data. The model is analyzed from a Bayesian perspective and has the benefit of automatically down-weighting time points close to motion spikes in a data-driven manner. We develop a highly efficient Markov Chain Monte Carlo (MCMC) algorithm that allows for Bayesian variable selection among the regressors to model both the mean (i.e., the design matrix) and variance. This makes it possible to include a broad range of explanatory variables in both the mean and variance (e.g., time trends, activation stimuli, head motion parameters and their temporal derivatives), and to compute the posterior probability of inclusion from the MCMC output. Variable selection is also applied to the lags in the autoregressive noise process, making it possible to infer the lag order from the data simultaneously with all other model parameters. We use both simulated data and real fMRI data from OpenfMRI to illustrate the importance of proper modeling of heteroscedasticity in fMRI data analysis. Our results show that the GLMH tends to detect more brain activity, compared to its homoscedastic counterpart, by allowing the variance to change over time depending on the degree of head motion.

    The full text will be freely available from 2018-05-01 10:46
  • 18.
    Azahar Ali, Md.
    et al.
    CSIR, India; Indian Institute Technology Hyderabad, India.
    Srivastava, Saurabh
    CSIR, India; Delhi Technology University, India.
    Agrawal, Ved V.
    CSIR, India.
    Willander, Magnus
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, Faculty of Science & Engineering.
    John, Renu
    Indian Institute Technology Hyderabad, India.
    Malhotra, Bansi D.
    Delhi Technology University, India.
    A biofunctionalized quantum dot-nickel oxide nanorod based smart platform for lipid detection2016In: Journal of materials chemistry. B, ISSN 2050-750X, E-ISSN 2050-7518, Vol. 4, no 15, 2706-2714 p.Article in journal (Refereed)
    Abstract [en]

    A reagent-free, low-cost and sensitive immunosensor has been fabricated using anti-apolipoprotein B (AAB) conjugated L-cysteine in situ capped cadmium sulfide quantum dots (CysCdS QDs) bound to nickel oxide nanorods (nNiO) for detection of low density lipoprotein (LDL) molecules in human serum samples. The structural and morphological properties of AAB conjugated CysCdS QDs and nNiO have been investigated using electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy and UV-visible techniques. In this immunosensor, the synthesized NiO nanorods act as mediators that allow the direct electron transfer due to their channeling effect resulting in a mediator-free biosensor. This mediator-free CysCdS-NiO based immunosensor shows improved characteristics such as a good sensitivity of 32.08 mu A (mg dl(-1))(-1) cm(-2) compared to that based on nNiO (1.42 mA (mg dl(-1))(-1) cm(-2)) alone for detection of lipid (LDL) molecules over a wide concentration range, 5-120 mg dl(-1) (0.015-0.36 mu M). The kinetic analysis yields an association constant (K-a) of 3.24 kM(-1) s(-1), indicating that the antibody conjugated CysCdS-NiO platform has a strong affinity towards lipid molecules. The excellent electron transport properties of the CysCdS-NiO nanocomposite in this immunosensor reveal that it provides an efficient platform for routine quantification of LDL molecules in real samples.

  • 19.
    Nilsson, Peter
    et al.
    n/a.
    Torkelsson, Mats
    n/a.
    Vesterbacka, Mark
    Linköping University, Department of Electrical Engineering, Electronics System. Linköping University, The Institute of Technology.
    Wanhammar, Lars
    Linköping University, Department of Electrical Engineering, Electronics System. Linköping University, The Institute of Technology.
    A bit-serial realization of a lattice wave digital intermediate frequency filter1993In: Proc. Sixth Annual IEEE Int. ASIC Conf. and Exhibit, ASIC'93, 1993, 197-200 p.Conference paper (Refereed)
    Abstract [en]

    A custom DSP chip for mobile radio systems like the American IS-54 system is presented. The application is a digital intermediate frequency filter which is intended to replace expensive analog filters. It is a lattice wave digital filter with fixed coefficient bit-serial arithmetic. A technique which is useful for area efficient layouts in high throughput real time signal processing is discussed.

  • 20.
    Hallander, Ingrid
    Linköping University, Department of Mechanical Engineering, Fluid and Mechanical Engineering Systems. Linköping University, The Institute of Technology.
    A broad perspective on life cycle considerations in product development2004Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    For products with long life cycles, operational and support costs represent a significant part of the total cost for the product. Moreover, such products frequently tend to be complex and contain a mixture of both mature. stable technology with bng life cycles and new technology with short life cycles. lt is therefore of great interest to industry to determine how to take these factors into consideration in an efficient way during product development.

    Another factor that affects product development for these and other kinds of products with shorter life cycles is interest in taking a wider view of the end-user or customer scenario, for instance by offering support and after sales services for the products. All these interests drive the demand to consider life cycle related issues in product development, not just life cycle cost. This also makes a life cycle perspective interesting for fums that produce products with shorter life cycles than the ones studied here through the opportunity for after market sales and services.

    This research has been explorative, aiming to understand how firms manage to take life cycle related demands into consideration during product development. The aim was to expand from a cost oriented focus to a wider focus, a value oriented focus, here called life cycle value. The dominant question has been "how" life cycle related demands are considered, focusing on barriers to and enablers for this. Equally important has been to determine the implication of life cycle value for different firms and industries and to find out where value is added in product development. A combination of a quantitative and qualitative research approach has been used to collect empirical data.

    One important finding was that there is an interest to deliver a solution to the customer rather than just a product, to consider customer revenue. This adds a new perspective to the implication of life cycle value, moving from a life cycle cost scenario to a life cycle cost versus revenue scenario. The results fom cases were categorized into six main attributes. These attributes were considered to be very influential and important for the ability to take life cycle perspective into account during product development.

    • Holistic Perspective
    • Requirements & Metrics
    • Leadership & Management/Knowledge management
    • Tools & Methods
    • Organizational Factors
    • Enterprise Relationships

    Within each of these attributes, several practices and lessons learned were identified. Some of the results are also worth investigating further in continued research:

    • Requirements formulation and management is considered to be critical. Well defined and clearly stated demands are key to taking life cycle issues into account due to the difficulty of incorporating life cycle related demands into the product. Nonetheless, balancing these demands against others is perceived to be difficult, and there is a clear need for tools, methods or models to support decision-making in this context.
    • The incorporation of new technology and services is another field of interest to industry. Organizational support and planning for technology insertion and new innovations and services into existing products and product lines are needed.
    • The organizational support to balance specialization and integration in a product development context, with a long-term focus
    • The effect of a transfer from delivering a product to delivering product and support services to the organization.
    List of papers
    1. Life cycle value in product development: a case study in the transportation industry
    Open this publication in new window or tab >>Life cycle value in product development: a case study in the transportation industry
    2003 (English)In: DS 31: Proceedings of ICED 03, the 14th International Conference on Engineering Design, Stockholm, Stockholm, Sweden: ICED'03 , 2003, 417-418 p.Conference paper, Published paper (Other academic)
    Abstract [en]

    Several factors prevent enterprises from having a holistic perspective during product development. Important aspects include increased product complexity and significant uncertainty with regard to technology. For products with a long life cycle this is extremely important since development and life cycle costs are high. The combination of complexity of system design and the limits of individual human comprehension typically make it difficult to envision a best value solution.

    In an attempt to encircle a more holistic perspective of value, the concept of Life Cycle Value has evolved within the Lean Aerospace Initiative, LAI. The implication of this is development of products incorporating life cycle and long-term focus including cost and performance and reliability factors. A similar perspective has evolved within the Lean Aircraft Research Program, LARP, in Sweden.

    This paper contributes a new study of how life cycle aspects are taken into consideration in a large corporation in the transportation industry. The purpose of the research was to examine relative contributions to product development and determine factors that significantly promote the ability to consider the life cycle perspective. The results will be discussed with respect to tools, methods, requirements, metrics, leadership and other organizational factors, innovation, and enterprise relationships.

    Place, publisher, year, edition, pages
    Stockholm, Sweden: ICED'03, 2003
    Keyword
    Life cycle, value, product development, transportation industry
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-36398 (URN)31246 (Local ID)1-904670-00-8 (ISBN)31246 (Archive number)31246 (OAI)
    Conference
    ICED 03, the 14th International Conference on Engineering Design, Stockholm
    Available from: 2009-10-10 Created: 2009-10-10 Last updated: 2013-12-03
    2. Lifecycle value framework for tactical aircraft product development
    Open this publication in new window or tab >>Lifecycle value framework for tactical aircraft product development
    2001 (English)Conference paper, Published paper (Other academic)
    Abstract [en]

    Due to a dramatic reduction in defense procurement, the benchmark for developing new defense systems today is performance at an affordable cost. In an attempt to encircle a more holistic perspective of value, lifecycle value has evolved as a concept within the Lean Aerospace Initiative, LAI. The implication of this is development of products incorporating lifecycle and long-term focus instead of a shortsighted cost cutting focus. The interest to reduce total cost of ownership while still improving performance, availability, and sustainability, other dimensions taken into account within the lifecycle value approach, falls well within this context. Several factors prevent enterprises from having a holistic perspective during product development. Some important aspects are increased complexity of the products and significant technological uncertainty. The combination of complexity in system design and the limits of individual human comprehension typically prevent a best value solution to be envisioned. The purpose of this research was to examine relative contributions in product development and determine factors that significantly promote abilities to consider and achieve lifecycle value. This paper contributes a maturity matrix based on important practices and lessons learned through extensive interview based case studies of three tactical aircraft programs, including experiences from more than 100 interviews.

    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-102199 (URN)
    Conference
    2001 Eleventh Annual International Symposium, Melbourne, Australia, 1-5 July 2001
    Available from: 2013-12-03 Created: 2013-12-03 Last updated: 2013-12-03
  • 21.
    Milberg, Per
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, The Institute of Technology.
    Bergman, Karl-Olof
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, The Institute of Technology.
    Norman, Henrik
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, The Institute of Technology.
    Pettersson, Roger B.
    Department of Wildlife, Fish and Environmental Studies, SLU, 901 83 Umea°, Sweden.
    Westerberg, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, The Institute of Technology.
    Wikars, Lars-Ove
    Hovgården 66, Borlänge, Sweden .
    Jansson, Nicklas
    Linköping University, Department of Physics, Chemistry and Biology, Biology. Linköping University, The Institute of Technology.
    A burning desire for smoke? Sampling insects favoured by forestfire in the absence of fire2015In: Journal of Insect Conservation, ISSN 1366-638X, E-ISSN 1572-9753, Vol. 19, no 1, 55-65 p.Article in journal (Refereed)
    Abstract [en]

    Fire-favoured insects are difficult to sampleexcept opportunistically after forest fires. Here, we tested ifsmoke from a small fire could be an efficient way to samplesuch insects. Insects were sampled over ca. 10 h hours, byhand-picking and netting on screens put up around the fire.Two specimens of the rare and redlisted Hormopeza spp.(Diptera, Empididae) were caught. Large numbers([20,000) of Microsania spp. (Diptera, Platypezidae) werecaught, but none in the absence of smoke. The numbers ofMicrosania spp. clearly peaked in late afternoon, and ashort sampling period would be sufficient if targeting onlythis taxon. Of the almost 200 species of Coleoptera, 17 %were considered as fire-favoured, contributing 9 % of thespecimens, suggesting low efficiency of the method for thisgroup. Using 23 sites differing in fire history, catches ofMicrosania spp. were unaffected by numbers and area offorest fire (preceding 5 years and within 10 km radius overthe sampling sites). In contrast, there was a weak trend forthe proportion of fire-favoured Coleoptera to increase withincreasing number of fires. To conclude, smoke as producedin our study can clearly attract fire-favoured Diptera,but smoke had only a weak effect on fire-favoured Coleopterain the study area. It is still likely that selectivelypicking specimens of species attracted to smoke is a morecost-efficient method than using, e.g., Malaise traps thatcatch indiscriminately.

  • 22.
    Borga, Magnus
    et al.
    Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, The Institute of Technology. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Friman, Ola
    Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, The Institute of Technology.
    Lundberg, Peter
    Linköping University, Department of Medical and Health Sciences, Radiation Physics. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Center for Surgery, Orthopaedics and Cancer Treatment, Department of Radiation Physics.
    Knutsson, Hans
    Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, The Institute of Technology.
    A canonical correlation approach to exploratory data analysis in fMRI2002Conference paper (Other academic)
    Abstract [en]

    A computationally efficient data-driven method for exploratory analysis of functional MRI data is presented. The basic idea is to reveal underlying components in the fMRI data that have maximum autocorrelation. The tool for accomplishing this task is Canonical Correlation Analysis. The proposed method is more robust and much more computationally efficient than independent component analysis, which previously has been applied in fMRI.

  • 23.
    Palfi, Miodrag
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Molecular and Clinical Medicine, Transfusion Medicine. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Immunology and Transfusion Medicine.
    Hildén, Jan-Olof
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Molecular and Clinical Medicine, Transfusion Medicine. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Immunology and Transfusion Medicine.
    Matthiesen, Leif
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Molecular and Clinical Medicine, Obstetrics and gynecology. Östergötlands Läns Landsting, Centre of Paediatrics and Gynecology and Obstetrics, Department of Gynecology and Obstetrics in Linköping.
    Selbing, Anders
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Molecular and Clinical Medicine, Obstetrics and gynecology. Östergötlands Läns Landsting, Centre of Paediatrics and Gynecology and Obstetrics, Department of Gynecology and Obstetrics in Linköping.
    Berlin, Gösta
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Molecular and Clinical Medicine, Transfusion Medicine. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Immunology and Transfusion Medicine.
    A case of severe Rh (D) alloimmunization treated by intensive plasma exchange and high-dose intravenous immunoglobulin2006In: Transfusion and apheresis science, ISSN 1473-0502, Vol. 35, no 2, 131-136 p.Article in journal (Refereed)
    Abstract [en]

    Background: In extremely severe Rh (D) alloimmunization, during pregnancy, early diagnosis and treatment is essential to avoid hydrops fetalis. Intrauterine transfusion (IUT) is of utmost importance in the prevention of fetal anemia but it is usually feasible only after 20 weeks of pregnancy. Therefore, additional treatment options in early pregnancy are needed. Study design and methods: A 27-year-old severely D + C immunized woman was admitted at 8 weeks of gestation in her fifth pregnancy with an extremely high concentration of anti-D. Her first pregnancy was uneventful but resulted in D + C alloimmunization. The next two pregnancies were unsuccessful, because of hydrops fetalis resulting in fetal death in pregnancy week 20 and 24, respectively, despite treatment with high-dose intravenous immunoglobulin (IVIG) and IUT treatment. A fourth pregnancy was terminated with legal abortion. The patient was eager and persistent to accomplish a successful pregnancy. Therefore, a combination of treatments consisting of plasma exchange (PE) three times/week and IVIG 100 g/week was started in pregnancy week 12. PE was performed 53 times and totally 159 L of plasma was exchanged. Results: The anti-D concentration was 12 μg/mL (IAT titer 2000) before start of treatment by PE and IVIG in pregnancy week 12. The concentration of anti-D was gradually reduced to approximately 3 μg/mL after only two weeks of treatment and was maintained at that level until pregnancy week 22. In pregnancy week 26 and 27, signs of hydrops were detected by ultrasonography and IUT were performed at each occasion. Sectio was inevitable at pregnancy week 28 + 1 and a male baby was born: Hb 58 g/L (cord sample) and 68 g/L (venous sample), weight 1385 g, Apgar score = 4-5-7, Bilirubin 56-150 mmol/L (4 h). Exchange transfusion was performed on day two and day five. Phototherapy was also implemented for eight days. The newborn's recovery thereafter was uneventful and complete. Conclusion: A combination of PE and IVIG may be an efficient treatment possible to start in early pregnancy in patients with extremely severe Rh (D) alloimmunization, with a history of hydrops fetalis in previous pregnancies. © 2006 Elsevier Ltd. All rights reserved.

  • 24.
    Mannerhagen, Anders
    Linköping University, Department of Computer and Information Science.
    A case study of nurses information and communication needs2009Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The role of information technology within health care is getting more central and prominent. The purpose of this change is both to make the health care more efficient and to heighten patient safety. This exploratory case study of four care units aims to provide a glimpse into the clinical work of nurses, and to indentify and describe their communication and information needs. The analytical framework used in this study is distributed cognition and the research method used is cognitive ethnography. The study provides a peek into the complex system of health care, and how the central artifacts such as patient records, whiteboards and different alarm systems are used in this context. The result of the study describes the current work practices and information flows in the studied care units. From these results general system design implications are made.

  • 25.
    Eghbali, Amir
    et al.
    Linköping University, Department of Electrical Engineering, Electronics System. Linköping University, The Institute of Technology.
    Johansson, Håkan
    Linköping University, Department of Electrical Engineering, Electronics System. Linköping University, The Institute of Technology.
    Löwenborg, Per
    Linköping University, Department of Electrical Engineering, Electronics System. Linköping University, The Institute of Technology.
    A Class of Multimode Transmultiplexers Based on the Farrow Structure2012In: Circuits, systems, and signal processing, ISSN 0278-081X, E-ISSN 1531-5878, Vol. 31, no 3, 961-985 p.Article in journal (Refereed)
    Abstract [en]

    This paper introduces multimode transmultiplexers (TMUXs) in which the Farrow structure realizes the polyphase components of general lowpass interpolation/decimation filters. As various lowpass filters are obtained by one set of common Farrow subfilters, only one offline filter design enables us to cover different integer sampling rate conversion (SRC) ratios. A model of general rational SRC is also constructed where the same fixed subfilters perform rational SRC. These two SRC schemes are then used to construct multimode TMUXs. Efficient implementation structures are introduced and different filter design techniques such as minimax and least-squares (LS) are discussed. By means of simulation results, it is shown that the performance of the transmultiplexer (TMUX) depends on the ripples of the filters. With the error vector magnitude (EVM) as the performance metric, the LS method has a superiority over the minimax approach.

  • 26.
    Strömbäck, Lena
    Linköping University, Department of Computer and Information Science, IISLAB - Laboratory for Intelligent Information Systems. Linköping University, The Institute of Technology.
    A classification for comparing standardized XML data2006In: Database and Expert Systems Applications, 2006. DEXA '06, Los Alamitos, CA, USA: IEEE Computer Society, 2006, 517-524 p.Conference paper (Refereed)
    Abstract [en]

    The increasing amount of XML data provided via the Web imposes a large need for efficient data exchange and import. This has led to an increasing interest in XML standards within a large number of areas. However, in most application domains there are several competing standards capturing the same kind of information. This work presents a method for classification and comparison of standards within an area. The method can be applied to XML-standards in any domain. We report on the situation for two different areas, molecular interactions and digital television and use our method to compare the standards within the two domains. The classification gives information on how similar the standards are, in terms of information content and structure. This information is useful for deciding which kind of methods are interesting for providing automatic matching and efficient development of tools for import of standardised data

  • 27.
    Shutova, T
    et al.
    Umeå University.
    Klimov, VV
    Russian Academy of Sciences.
    Andersson, Bertil
    Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Faculty of Health Sciences.
    Samuelsson, G
    Umeå University.
    A cluster of carboxylic groups in PsbO protein is involved in proton transfer from the water oxidizing complex of Photosystem II2007In: Biochimica et Biophysica Acta - Bioenergetics, ISSN 0005-2728, E-ISSN 1879-2650, Vol. 1767, no 6, 434-440 p.Article in journal (Refereed)
    Abstract [en]

    The hypothesis presented here for proton transfer away from the water oxidation complex of Photosystem II (PSII) is supported by biochemical experiments on the isolated PsbO protein in solution, theoretical analyses of better understood proton transfer systems like bacteriorhodopsin and cytochrome oxidase, and the recently published 3D structure of PS II (Pdb entry IS5L). We propose that a cluster of conserved glutamic and aspartic acid residues in the PsbO protein acts as a buffering network providing efficient acceptors of protons derived from substrate water molecules. The charge delocalization of the cluster ensures readiness to promptly accept the protons liberated from substrate water. Therefore protons generated at the catalytic centre of PSII need not be released into the thylakoid lumen as generally thought. The cluster is the beginning of a localized, fast proton transfer conduit on the lumenal side of the thylakoid membrane Proton-dependent conformational changes of PsbO may play a role in the regulation of both supply of substrate water to the water oxidizing complex and the resultant proton transfer.

  • 28.
    Schmitz, Marcus
    et al.
    Dept. of Electronics and Computer Science University of Southampton.
    Al Hashimi, Bashir M.
    Dept. of Electronics and Computer Science University of Southampton.
    Eles, Petru Ion
    Linköping University, The Institute of Technology. Linköping University, Department of Computer and Information Science, ESLAB - Embedded Systems Laboratory.
    A Co-Design Methodology for Energy-Efficient Multi-Mode Embedded Systems with Consideration of Mode Execution Probabilities2003In: Design Automation and Test in Europe DATE 2003 Conference,2003, Munich, Germany: IEEE Computer Society Press , 2003, 960- p.Conference paper (Refereed)
    Abstract [en]

    Multi-mode systems are characterised by a set of interacting operational modes to support different functionalities and standards. In this paper, we present a co-design methodology for multi-mode embedded systems that produces energy-efficient implementations. Based on the key observation that operational modes are executed with different probabilities, i.e., the system spends uneven amounts of time in the different modes, we develop a novel codesign technique that exploits this property to significantly reduce energy dissipation. We conduct several experi-ments, including a smart phone real-life example, that demonstrate the effectiveness of our approach. Reductions in power consumption of up to 64% are reported.

  • 29.
    Sjöqvist, Jonas
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Computational Physics. Linköping University, The Institute of Technology.
    González-Cano, Rafael C.
    University of Málaga, Spain.
    López Navarette, Juan T.
    University of Málaga, Spain.
    Casado, Juan
    University of Málaga, Spain.
    Ruiz Delgado, M. Carmen
    University of Málaga, Spain.
    Linares, Mathieu
    Linköping University, Department of Physics, Chemistry and Biology, Computational Physics. Linköping University, The Institute of Technology.
    Norman, Patrick
    Linköping University, Department of Physics, Chemistry and Biology, Computational Physics. Linköping University, The Institute of Technology.
    A combined MD/QM and experimental exploration of conformational richness in branched oligothiophenes2014In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 16, no 45, 24841-24852 p.Article in journal (Refereed)
    Abstract [en]

    Infrared (IR) absorption and vibrational Raman spectra of a family of branched oligothiophenes have been determined experimentally as well as theoretically. The molecular spectra have been compared to those of the linear analogues, with identification made of spectral features due to structural properties that are valued in organic solar cell applications. The theoretical spectra have been obtained through a newly developed method in which individual conformer spectra, calculated at the time-dependent DFT level in this work, are weighted by statistics extracted from classical molecular dynamics trajectories. The agreement with experiment for the resulting averaged spectra is at least as good as, and often better than, what is observed for Boltzmann-weighted spectra. As the weights are available before the costly step of spectrum calculation, the method has the additional advantage of enabling efficient approximations. For simulating the molecular dynamics of the studied α,β-linked thiophenes and 2-methylthiophenes, high quality parameters have been derived for the CHARMM force field. Furthermore, the temperature dependence of the IR and Raman spectra have been investigated, both experimentally and theoretically.

  • 30.
    Östberg, Gustav
    Linköping University, Department of Electrical Engineering.
    A Comparative Study of Efficient Power Amplifiers in CMOS2008Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    During later years communication schemes for handheld devices have increased in complexity due to the desire to increase the throughput, i.e. the amount of information sent over a medium simultaneously. Increasing throughput can be accomplished, not only by modulating the phase or frequency, but also the amplitude. This leads to tougher requirements on the power amplifier. The conventional power amplifiers, which have the ability to follow the envelope of the carrier, are inefficient. This thesis aims to compare two old but revived architectures which exploit high-efficiency amplifiers and still have a linear relationship between the input and output. The architectures; the Polar Linearization Technique and Outphasing share the same foundation. Based on literature, the polar technique have been more successful of employing examples fufilling communication standards. The polar technique is also more versatile regarding power combiners, distortion correction and alternative implementations. The simulations performed in this thesis results show that the polar amplifier is less sensitive to process variations and has higher maximum efficiency. On the other hand, the outphasing topology have the highest linearity figures.

  • 31.
    Daneva (Mitradjieva), Maria
    et al.
    Linköping University, Department of Mathematics, Optimization . Linköping University, The Institute of Technology.
    Larsson, Torbjörn
    Linköping University, Department of Mathematics, Optimization . Linköping University, The Institute of Technology.
    Patriksson, Michael
    Mathematical Sciences, Chalmers University of Technology and Göteborg University, Gothenburg, Sweden.
    Rydergren, Clas
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    A Comparison of Feasible Direction Methods for the Stochastic Transportation Problem2010In: Computational optimization and applications, ISSN 0926-6003, E-ISSN 1573-2894, Vol. 46, no 3, 451-466 p.Article in journal (Refereed)
    Abstract [en]

    The feasible direction method of Frank and Wolfe has been claimed to be efficient for solving the stochastic transportation problem. While this is true for very moderate accuracy requirements, substantially more efficient algorithms are otherwise diagonalized Newton and conjugate Frank–Wolfe algorithms, which we describe and evaluate. Like the Frank–Wolfe algorithm, these two algorithms take advantage of the structure of the stochastic transportation problem. We also introduce a Frank–Wolfe type algorithm with multi-dimensional search; this search procedure exploits the Cartesian product structure of the problem. Numerical results for two classic test problem sets are given. The three new methods that are considered are shown to be superior to the Frank–Wolfe method, and also to an earlier suggested heuristic acceleration of the Frank–Wolfe method.

  • 32.
    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.

  • 33.
    Öberg, Lasse
    et al.
    Linköping University, Department of Electrical Engineering. Linköping University, The Institute of Technology.
    Xu, Youzhi
    A Complete Energy Dissipation Model for Wireless Sensor Networks2007In: In Proceedings of the International Conference on Sensor Technologies and Applications, Valencia, Spain, October 14-20, IEEE , 2007, 531-540 p.Conference paper (Refereed)
    Abstract [en]

    Advances in both microelectronics and wireless commu- nication technology have made it possible to develop and manufacture low cost and energy efficient sensor nodes. To compare different designs and protocols with respect to both energy and delay constraints an energy dissipation model is needed that takes these aspects into account. In this paper we propose a complete energy dissipation model for wire- less sensor networks that uses four operation states. These states are based on the basic sensor nodes architecture and actual working conditions of a sensor node. It also takes into account the transition between the operation states, such that a decision to change operation state can be more accurately determined. In this paper we also present mea- sured values for both the power consumed in each operation state and the time it takes to complete a transition between two operation states.

  • 34.
    Munjulury, Raghu Chaitanya
    et al.
    Linköping University, Department of Management and Engineering, Fluid and Mechatronic Systems. Linköping University, Faculty of Science & Engineering.
    Nadali Najafabadi, Hossein
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, Faculty of Science & Engineering.
    Safavi, Edris
    Linköping University, Department of Management and Engineering, Machine Design. Linköping University, Faculty of Science & Engineering.
    Ölvander, Johan
    Linköping University, Department of Management and Engineering, Machine Design. Linköping University, Faculty of Science & Engineering.
    Petter, Krus
    Linköping University, Department of Management and Engineering, Fluid and Mechatronic Systems. Linköping University, Faculty of Science & Engineering.
    Karlsson, Matts
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, Faculty of Science & Engineering.
    A comprehensive computational multidisciplinary design optimization approach for a tidal power plant turbine2017In: Advances in Mechanical Engineering, ISSN 1687-8132, E-ISSN 1687-8140, Vol. 9, no 3, 1-13 p., 1687814017695174Article in journal (Refereed)
    Abstract [en]

    Multidisciplinary design optimization has become a powerful technique to facilitate continuous improvement of complex and multidisciplinary products. Parametric modeling is an essential part with tremendous impact on the flexibility and robustness of multidisciplinary design optimization. This article investigates the effect of relational and non-relational parameterization techniques on the robustness and flexibility of the conceptual design of a multidisciplinary product. Bench marking between relational and non-relational parameterization and their effect on flexibility and robustness indicate that the relational parameterization is an efficient method in the multidisciplinary design optimization process. The inherent properties of the method contribute to an efficient parametric modeling with improved communication between different disciplines. This enhances the performance of the multidisciplinary design optimization process and allows a more flexible and robust design. The considered disciplines are computer-aided design, computational fluid dynamics, finite element analysis, and dynamic simulation. A high-fidelity geometry created in a computer-aided design environment is computer-aided design centric approach and later used in computational fluid dynamics, finite element analysis for a better understanding of the product as it leads to precise outcomes. The proposed approach is implemented for the conceptual design of a novel product, a tidal power plant developed by Minesto AB using a multidisciplinary design optimization process.

  • 35.
    Karlsson, Fredrik
    et al.
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, The Institute of Technology.
    Moshfegh, Bahram
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, The Institute of Technology.
    A comprehensive investigation of a low-energy building in Sweden2007In: Renewable Energy, ISSN 0960-1481, Vol. 32, no 11, 1830-1841 p.Article in journal (Refereed)
    Abstract [en]

    In Sweden, the building sector alone accounts for almost 40% of the total energy demand and people spend more than 80% of their time indoors. Reducing energy demand in the buildings is essential to the achievement of a sustainable built environment. At the same time, it is important to not deteriorate people's health, well-being and comfort in buildings. Thus, designing healthy and energy efficient buildings are one of the most challenging tasks for building scientists. A low-energy building that uses less than half of the purchased energy of a comparable typical Swedish building has been investigated from different viewpoints in an attempt to represent the building at different system levels. First, the ventilation performance in different rooms using the tracer gas method is reported. Second, results from simulations and in situ measurements are used to analyse the building's power demand and energy performance. The household's behaviour and their impact on energy usage as well as acceptance are reported. Finally, the CO2 emissions with regard to the energy usage are analysed on the basis of different supply energy forms from surrounding energy systems, for example a Swedish and European electricity mix, or district heating as a substitute for electrical heating.

  • 36.
    Johansson, Jonas
    et al.
    Linköping University, Department of Science and Technology, Physics and Electronics. Linköping University, The Institute of Technology.
    Belov, Ilja
    Jönköping University, School of Engineering, Department of Mechanical Engineering, Jönköping.
    Johnson, Erland
    SP Technical Research Institute of Sweden, Borås, Sweden.
    Leisner, Peter
    SP Technical Research Institute of Sweden, Borås, Sweden.
    A computational method for evaluating the damage in a solder joint of an electronic package subjected to thermal loadsManuscript (preprint) (Other academic)
    Abstract [en]

    Purpose – The purpose of this paper is to introduce a novel computational method to evaluate damage accumulation in a solder joint of an electronic package, when exposed to operating temperature environment. A procedure to implement the method is suggested, and a discussion of the method and its possible applications is provided in the paper.

    Originality/value – The method enables increased accuracy in thermal fatigue life prediction of solder joints. Combined with other failure mechanisms, it may contribute to the accuracy of reliability assessment of electronic packages.

    Design/methodology/approach – Methodologically, interpolated response surfaces based on specially designed finite element simulation runs, are employed to compute a damage metric at regular time intervals of an operating temperature profile. The developed method has been evaluated on a finite-element model of a lead-free PBGA256 package, and accumulated creep strain energy density has been chosen as damage metric.

    Findings – The method has proven to be two orders of magnitude more computationally efficient compared to finite element simulation. A general agreement within 3% has been found between the results predicted with the new method, and finite element simulations when tested on a number of temperature profiles from an avionic application. The solder joint temperature ranges between +25°C and +75°C.

    Practical implications – The method can be implemented as part of reliability assessment of electronic packages in the design phase.

  • 37. Hilding, D.
    et al.
    Torstenfelt, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Management and Engineering, Solid Mechanics .
    Klarbring, Anders
    Linköping University, The Institute of Technology. Linköping University, Department of Management and Engineering, Mechanics .
    A computational methodology for shape optimization of structures in frictionless contact2001In: Computer Methods in Applied Mechanics and Engineering, ISSN 0045-7825, Vol. 190, no 31, 4043-4060 p.Article in journal (Refereed)
    Abstract [en]

    This paper presents a computational methodology for shape optimization of structures in frictionless contact, which provides a basis for developing user-friendly and efficient shape optimization software. For evaluation it has been implemented as a subsystem of a general finite element software. The overall design and main principles of operation of this software are outlined. The parts connected to shape optimization are described in more detail. The key building blocks are: analytic sensitivity analysis, an adaptive finite element method, an accurate contact solver, and a sequential convex programing optimization algorithm. Results for three model application examples are presented, in which the contact pressure and the effective stress are optimized. cr 2001 Elsevier Science B.V. All rights reserved.

  • 38.
    Guardiola, C
    et al.
    University of Politecn Valencia, Spain .
    Pla, B
    University of Politecn Valencia, Spain .
    Blanco-Rodriguez, D
    University of Politecn Valencia, Spain .
    Eriksson, Lars
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    A computationally efficient Kalman filter based estimator for updating look-up tables applied to NOx estimation in diesel engines2013In: Control Engineering Practice, ISSN 0967-0661, Vol. 21, no 11, 1455-1468 p.Article in journal (Refereed)
    Abstract [en]

    No-x estimation in diesel engines is an up-to-date problem but still some issues need to be solved. Raw sensor signals are not fast enough for real-time use while control-oriented models suffer from drift and aging. A control-oriented gray box model based on engine maps and calibrated off-line is used as benchmark model for No-x estimation. Calibration effort is important and engine data-dependent. This motivates the use of adaptive look-up tables. In addition to, look-up tables are often used in automotive control systems and there is a need for systematic methods that can estimate or update them on-line. For that purpose, Kalman filter (KF) based methods are explored as having the interesting property of tracking estimation error in a covariance matrix. Nevertheless, when coping with large systems, the computational burden is high, in terms of time and memory, compromising its implementation in commercial electronic control units. However look-up table estimation has a structure, that is here exploited to develop a memory and computationally efficient approximation to the KF, named Simplified Kalman filter (SKF). Convergence and robustness is evaluated in simulation and compared to both a full KF and a minimal steady-state version, that neglects the variance information. SKF is used for the online calibration of an adaptive model for No-x estimation in dynamic engine cycles. Prediction results are compared with the ones of the benchmark model and of the other methods. Furthermore, actual online estimation of No-x is solved by means of the proposed adaptive structure. Results on dynamic tests with a diesel engine and the computational study demonstrate the feasibility and capabilities of the method for an implementation in engine control units.

  • 39.
    Hjalmarson, Emil
    Linköping University, Department of Electrical Engineering, Electronics System. Linköping University, The Institute of Technology.
    A computer-aided approach to design of robust analog circuits2006Doctoral thesis, monograph (Other academic)
    Abstract [en]

    Traditional design methods for analog circuits are based on rules-of-thumbs, experience, and trial-and-error approaches involving the use of circuit simulators. It is an unstructured process, which is time-consuming, error prone, and requires the attention of a skilled analog designer. This situation calls for design methodologies that are more efficient.

    We have developed an efficient approach and corresponding tools that address these issues. A computer-aided design tool for design of large analog circuits with low level of human intervention has been developed. The tool combines efficient performance measure evaluation and optimization methods to determine the device sizes and generate layouts for analog circuits. Large analog circuits with about 200 devices have been designed. The circuits are optimized with respect to, e.g., power consumption, and subject to a large number of performance requirements. All performance measures are automatically derived, which reduces the probability of introducing errors.

    Experimental results indicate that our approach can be used to design robust high-performance analog circuits with improved performance compared to manual approaches. Furthermore, the computer-aided tool decreases both the overall design time and the time required of a skilled designer.

    To accomplish this, an optimization strategy that enables device sizing without an initial design has been developed. Robust circuits are obtained by taking the variations in the manufacturing process into account. Degrading layout effects are also considered using a parasitic feedback technique. To gain insight and allow exploration of the complex relation between performance measures in analog circuits, we have developed techniques for design space exploration.

  • 40.
    Eek, Magnus
    et al.
    Saab Aeronaut, Aircraft Vehicle Syst, Modeling and Simulat, SE-58188 Linkoping, Sweden.
    Hallqvist, Robert
    Saab Aeronaut, Aircraft Vehicle Syst, Modeling and Simulat, SE-58188 Linkoping, Sweden.
    Gavel, Hampus
    Saab Aeronaut, Aeronaut Engn and Weapons, SE-58188 Linkoping, Sweden.
    Ölvander, Johan
    Linköping University, Department of Management and Engineering, Machine Design. Linköping University, Faculty of Science & Engineering.
    A Concept for Credibility Assessment of Aircraft System Simulators2016In: JOURNAL OF AEROSPACE INFORMATION SYSTEMS, ISSN 1940-3151, Vol. 13, no 6, 219-233 p.Article in journal (Refereed)
    Abstract [en]

    An efficient methodology for verification, validation, and credibility assessment of simulation models and simulator applications is an enabler for the aeronautical industrys increasing reliance on modeling and simulation in system design and verification and on training. As a complement to traditional document-centric approaches, this paper presents a method for credibility assessment of simulator applications, in which credibility information is presented to end users directly during simulation. The central idea is that each model in a simulator is extended with a metamodel describing different aspects of credibility. The metamodel includes a number of static credibility measures and a dynamic measure that may vary during simulation. The concept is implemented and tested in two system simulators for the Saab Gripen fighter aircraft. According to the evaluation, the concept facilitates an intuitive overview of model dependencies, as well as credibility information for individual models and for a simulator as a whole. This implies a support for detecting test plan deficiencies or that a simulator configuration is not a suitable platform for the execution of a particular test. Furthermore, model developers and end users are encouraged to reflect upon central credibility aspects like intended use, model fidelity, and test worthiness in their daily work.

  • 41.
    Nguyen, Hoang
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Evangelista, Gianpaolo
    Linköping University, Department of Science and Technology, Digital Media. Linköping University, The Institute of Technology.
    A continuous wavelet-Galerkin method for the linear wave equation2007In: SIAM Journal on Scientific Computing, ISSN 1064-8275, E-ISSN 1095-7197Article in journal (Other academic)
    Abstract [en]

    We consider the continuous space-time Galerkin method for the linear second-order wave equation proposed by French and Peterson in 1996. A bottleneck for this approach is how to solve the discrete problems effectively. In this paper, we tackle this bottleneck by essentially employing wavelet bases in space. We show how to decouple the corresponding linear system and we prove that the resulting subsystems can be uniformly preconditioned by simple diagonal preconditioners, leading to efficient iterative solutions.

  • 42.
    Chhetri, Dhurv
    et al.
    Linköping University, Department of Electrical Engineering, Electronics System. Linköping University, The Institute of Technology.
    Manyam, Venkata Narasimha
    Linköping University, Department of Electrical Engineering, Electronics System. Linköping University, The Institute of Technology.
    A Continuous-Time ADC and DSP for Smart Dust2011Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Recently, smart dust or wireless sensor networks are gaining more attention.These autonomous, ultra-low power sensor-based electronic devices sense and process burst-type environmental variations and pass the data from one node (mote) to another in an ad-hoc network. Subsystems for smart dust are typically the analog interface (AI), analog-to-digital converter (ADC), digital signal processor (DSP), digital-to-analog converter (DAC), power management, and transceiver for communication.

    This thesis project describes an event-driven (ED) digital signal processing system (ADC, DSP and DAC) operating in continuous-time (CT) with smart dust as the target application. The benefits of the CT system compared to its conventional counterpart are lower in-band quantization noise and no requirement of a clock generator and anti-aliasing filter, which makes it suitable for processing burst-type data signals.

    A clockless EDADC system based on a CT delta modulation (DM) technique is presented. The ADC output is digital data, continuous in time, known as “data token”. The ADC employs an unbuffered, area efficient, segmented resistor-string (R-string) feedback DAC. A study of different segmented R-string DAC architectures is presented. A comparison in component reduction with prior art shows nearly 87.5% reduction of resistors and switches in the DAC and the D flip-flops in the bidirectional shift registers for an 8-bit ADC, utilizing the proposed segmented DAC architecture. The obtained SNDR for the 3-bit, 4-bit and 8-bit ADC system is 22.696 dB, 30.435 dB and 55.73 dB, respectively, with the band of interest as 220.5 kHz.

    The CTDSP operates asynchronously and process the data token obtained from the EDADC. A clockless transversal direct-form finite impulse response (FIR) low-pass filter (LPF) is designed.

    Systematic top-down test-driven methodology is employed through out the project. Initially, MATLAB models are used to compare the CT systems with the sampled systems. The complete CTDSP system is implemented in Cadence design environment.

    The thesis has resulted in two conference contributions. One for the 20th European Conference on Circuit Theory and Design, ECCTD’11 and the other for the 19th IFIP/IEEE International Conference on Very Large Scale Integration, VLSI-SoC’11. We obtained the second-best student paper award at the ECCTD.

  • 43.
    Bengtsson, Mikael
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, Faculty of Science & Engineering.
    A Control-Oriented 0D Model of a Turbocharger Gas Stand Including Heat Transfer2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    A turbocharger’s performance is measured in a gas stand in order to provide information of the components characteristics. The measurement procedure is a very time consuming process and it is thus desired to make it more time-efficient.

    To allow for development of an enhanced control strategy used during the measurements, a 0D model of a gas stand is developed. The physical gas stand components are modeled and validated against measurements, all showing a reasonable result. Turbocharger heat transfers are investigated and modeled using a lumped capacitance approach. The heat transfer models shows approximative results when comparing with measurements which is explained by the lack of temperature measurement made on the bearing housing.

    When the complete gas stand model is validated against measurements, an improvement of the measurement procedure is examined. By adding an idealized heat source with the possibility to heat the compressor housing, it is possible to reduce the time it takes to reach an equilibrium when switching between two steady state operating points. 

  • 44.
    Lyzell, Christian
    et al.
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    Andersen, Martin
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    Enqvist, Martin
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    A Convex Relaxation of a Dimension Reduction Problem Using the Nuclear Norm2012In: Proceedings of the 51st IEEE Conference on Decision and Control, 2012, 2852-2857 p.Conference paper (Refereed)
    Abstract [en]

    The estimation of nonlinear models can be a challenging problem, in particular when the number of available data points is small or when the dimension of the regressor space is high. To meet these challenges, several dimension reduction methods have been proposed in the literature, where a majority of the methods are based on the framework of inverse regression. This allows for the use of standard tools when analyzing the statistical properties of an approach and often enables computationally efficient implementations. The main limitation of the inverse regression approach to dimension reduction is the dependence on a design criterion which restricts the possible distributions of the regressors. This limitation can be avoided by using a forward approach, which will be the topic of this paper. One drawback with the forward approach to dimension reduction is the need to solve nonconvex optimization problems. In this paper, a reformulation of a well established dimension reduction method is presented, which reveals the structure of the optimization problem, and a convex relaxation is derived.

  • 45.
    Ruggiero, Martino
    et al.
    DEIS University of Bologna, Italy.
    Gioia, Pari
    DEIS University of Bologna, Italy.
    Alessio, Guerri
    DEIS University of Bologna, Italy.
    Benini, Luca
    DEIS University of Bologna, Italy.
    Michela, Milano
    DEIS University of Bologna, Italy.
    Bertozzi, Davide
    ENDIF University of Ferrara, Italy.
    Andrei, Alexandru
    Linköping University, The Institute of Technology. Linköping University, Department of Computer and Information Science, ESLAB - Embedded Systems Laboratory.
    A Cooperative, Accurate Solving Framework for Optimal Allocation, Scheduling and Frequency Selection on Energy-Efficient MPSoCs2006In: Intl. Symposium on System-on-Chip SOC06,2006, 2006Conference paper (Refereed)
    Abstract [en]

    Most problems addressed by the software optimization flow for multi-processor systems-on-chip (MPSoCs) are NP-complete, and have been traditionally tackled by means of heuristics and highlevel approximations. Complete approaches have been effectively deployed only under unrealistic simplifying assumptions. We propose a novel methodology to formulate and solve to optimality the allocation, scheduling and discrete voltage selection problem for variable voltage/frequency MPSoCs, minimizing the system energy dissipation and the overhead for frequency switching. We integrate the optimization and validation steps to increase the accuracy of cost models and the confidence in quality of results. Two demonstrators are used to show the viability of the proposed methodology.

  • 46.
    Andersson, Håkan
    et al.
    Linköping University, Department of Management and Engineering. Linköping University, Faculty of Science & Engineering. Construct Tools PC AB, Sweden.
    Nordin, Peter
    Linköping University, Department of Management and Engineering. Linköping University, Faculty of Science & Engineering.
    Borrvall, Thomas
    DYNAmore Nordic AB, Brigadgatan 5, S-58758 Linkoping, Sweden.
    Simonsson, Kjell
    Linköping University, Department of Management and Engineering, Solid Mechanics. Linköping University, Faculty of Science & Engineering.
    Hilding, Daniel
    DYNAmore Nordic AB, Brigadgatan 5, S-58758 Linkoping, Sweden.
    Schill, Mikael
    DYNAmore Nordic AB, Brigadgatan 5, S-58758 Linkoping, Sweden.
    Krus, Petter
    Linköping University, Department of Management and Engineering, Fluid and Mechatronic Systems. Linköping University, Faculty of Science & Engineering.
    Leidermark, Daniel
    Linköping University, Department of Management and Engineering, Solid Mechanics. Linköping University, Faculty of Science & Engineering.
    A co-simulation method for system-level simulation of fluid-structure couplings in hydraulic percussion units2017In: Engineering with Computers, ISSN 0177-0667, E-ISSN 1435-5663, Vol. 33, no 2, 317-333 p.Article in journal (Refereed)
    Abstract [en]

    This paper addresses a co-simulation method for fluid power driven machinery equipment, i.e. oil hydraulic machinery. In these types of machinery, the fluid-structure interaction affects the end-product performance to a large extent, hence an efficient co-simulation method is of high importance. The proposed method is based on a 1D system model representing the fluid components of the hydraulic machinery, within which structural 3D Finite Element (FE) models can be incorporated for detailed simulation of specific sub-models or complete structural assemblies. This means that the fluid system simulation will get a more accurate structural response, and that the structural simulation will get more correct fluid loads at every time step, compared to decoupled analysis. Global system parameters such as fluid flow, performance and efficiency can be evaluated from the 1D system model simulation results. From the 3D FE-models, it is possible to evaluate displacements, stresses and strains to be used in stress analysis, fatigue evaluation, acoustic analysis, etc. The method has been implemented using two well-known simulation tools for fluid power system simulations and FE-simulations, respectively, where the interface between the tools is realised by use of the Functional Mock-up Interface standard. A simple but relevant model is used to validate the method.

  • 47.
    Song, Wenyan
    et al.
    School of Economics and Management, Beihang University, Beijing, China.
    Sakao, Tomohiko
    Linköping University, Department of Management and Engineering, Environmental Technology and Management. Linköping University, Faculty of Science & Engineering.
    A customization-oriented framework for design of sustainable product/service system2017In: Journal of Cleaner Production, ISSN 0959-6526, E-ISSN 1879-1786, Vol. 140, 1672-1685 p.Article in journal (Refereed)
    Abstract [en]

    Many manufacturers today are striving to offer high value-added Product/Service System (PSS) due to increasing competition and environmental pressure. PSS design activities face a variety of challenges such as a high level of customization as well as its resulting challenges, i.e., hidden requirements in product use phase, potential conflicts of design attributes, and internal complexity of service processes. However, existing insights for PSS customization are fragmented and insufficient to support manufacturers. Thus, it is necessary to develop a systematic and comprehensive support to solve those issues. In order to support PSS customization in early design phase, this paper proposes a design framework that involves a design process. The proposed design framework is module-based and thus flexible according to the user needs. In addition, it takes advantage of some existing methods. A case study of elevator PSS design shows the feasibility and potentials of the design framework and its associated design process to its broad usage in industry.

    The full text will be freely available from 2018-09-19 13:21
  • 48.
    Wallin, Ragnar
    et al.
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    Kao, Chung-Yao
    University of Melbourne, Australia.
    Hansson, Anders
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    A Cutting Plane Method for Solving KYP-SDPs2006Report (Other academic)
    Abstract [en]

    Semidefinite programs originating from the Kalman-Yakubovich-Popov lemma are convex optimization problems and there exist polynomial time algorithms that solve them. However, the number of variables is often very large making the computational time extremely long. Algorithms more efficient than general purpose solvers are thus needed. To this end structure exploiting algorithms have been proposed, based on the dual formulation. In this paper a cutting plane algorithm is proposed. In a comparison with a general purpose solver and a structure exploiting solver it is shown that the cutting plane based solver can handle optimization problems of much higher dimension.

  • 49.
    Wallin, Ragnar
    et al.
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    Kao, Chung-Yao
    University of Melbourne, Australia.
    Hansson, Anders
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    A Cutting Plane Method for Solving KYP-SDPs2008In: Automatica, ISSN 0005-1098, Vol. 44, no 2, 418-429 p.Article in journal (Refereed)
    Abstract [en]

    Semidefinite programs originating from the Kalman-Yakubovich-Popov lemma are convex optimization problems and there exist polynomial time algorithms that solve them. However, the number of variables is often very large making the computational time extremely long. Algorithms more efficient than general purpose solvers are thus needed. To this end structure exploiting algorithms have been proposed, based on the dual formulation. In this paper a cutting plane algorithm is proposed. In a comparison with a general purpose solver and a structure exploiting solver it is shown that the cutting plane based solver can handle optimization problems of much higher dimension.

  • 50.
    Rasheed, Yasser
    Linköping University, Department of Computer and Information Science.
    A database solution for scientific data from driving simulator studies.2011Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Many research institutes produce a huge amount of data. It was said by someone that “We are drowning in data, but starving of information”. This is particularly true for scientific data. The needs and the advantages of being able to search data from different experiments are increasing in order to look for differences and similarities among them and thus doing Meta studies. A Meta-study is the method that takes data from different independent studies and integrate them using statistical analysis. If data is well described and data access is flexible then it is possible to establish unexpected relationships among data. It also helps in the re-using of data from studies that have already been conducted which saves time, money and resources.

    In this thesis, we explore at the ways to store data from experiments and to make finding cross-experiments more efficient. The main aim of this thesis work is to propose a database solution for storing time series data generated by different simulators and to investigate the feasibility of using it with ICAT. ICAT is a metadata system used for searching and browsing of scientific data. This thesis has been completed in two steps. The first step is aimed at proposing an efficient database solution for storing time series data. The second step is aimed at investigating the feasibility of using ICAT and proposed database solution together. We found out that it is feasible to use ICAT as a metadata system for scientific studies. Since it is free and open source, it can be linked to any system and customized according to the needs.

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