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  • 1.
    Li, Jia
    Linköping University, Department of Electrical Engineering.
    10G GPON Management System Study and Implementation2009Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This thesis includes the GPON management system concept study and implementation work to translate the command line interface management mechanism to a user friendly GUI (graphic user interface). The original system was developed in C program with a client-server structure. The new system retains the same communication structure and protocol interface between the OLT PON card and user workstations. On the workstation side, a new GUI management client application is developed in Java to offer the similar functionalities as the original one, and a totally new graphic real-time system traffic statistics function is integrated to make it easier for user to monitor system traffic information in real time.

     

    The main object of this project is to study the GPON specifications, and understand GPON system working procedure and traffic transmission principle. On the other hand, ‘original system management application’ study is necessary including third party documentation reading and C code understanding. This study has resulted in the development of a new application in Java with third party user libraries and plug-ins. This new application has been tested using basic function tests executed in the GPON lab environment.

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

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

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

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

  • 3.
    Bergh, Torsten
    et al.
    Swedish Transport Adm, Sweden; Movea Trafikkonsult, Sweden.
    Remgard, Mats
    Swedish Transport Adm, Sweden.
    Carlsson, Arne
    Swedish National Rd and Transport Research Institute, Linköping, Sweden.
    Olstam, Johan
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering. Swedish National Road and Transport Research Institute, Linköping, Sweden.
    Strömgren, Per
    Movea Trafikkonsult, Sweden.
    2+1-roads Recent Swedish Capacity and Level-of-Service Experience2016In: INTERNATIONAL SYMPOSIUM ON ENHANCING HIGHWAY PERFORMANCE (ISEHP), (7TH INTERNATIONAL SYMPOSIUM ON HIGHWAY CAPACITY AND QUALITY OF SERVICE, 3RD INTERNATIONAL SYMPOSIUM ON FREEWAY AND TOLLWAY OPERATIONS), ELSEVIER SCIENCE BV , 2016, Vol. 15, 331-345 p.Conference paper (Refereed)
    Abstract [en]

    The first Swedish 2+1 median barrier road was opened in 1998. The concept was to retrofit the standard existing two-lane 13 m paved width cross-section at 90 and 110 kph posted speed limit without widening. This design has one continuous lane in each direction, a middle lane changing direction every one to three kilometres with a median barrier separating the two traffic directions. Today over 2 700 km 2+1 median barrier roads are opened for traffic. AADTs vary from some 3 000 to 20 000 with an average just below 10 000 nowadays normally with 100 kph. The concept has lately been enhanced also to cover the existing 9 m paved width cross-section. The design concept is the same from a drivers viewpoint, one continuous lane in each direction with a middle lane changing direction and a separating median barrier. This is created by introducing a continuous median barrier and adding overtaking lanes within an overtaking strategy. The differences are the existence of 1+1-sections, less overtaking opportunities and a slightly more narrow cross-section. Some 15 projects are opened. The purpose of this paper is to summarize present knowledge on level-of-service issues as they are presented in Swedish design and assessment guidelines and to give an overview of field measurements and theoretical analytical and simulation studies supporting the recommendations.

  • 4.
    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.

  • 5.
    Hall, Henning
    et al.
    Linköping University, Department of Computer and Information Science. Linköping University, The Institute of Technology.
    Luckey, Christian
    Linköping University, Department of Computer and Information Science. Linköping University, The Institute of Technology.
    3G Transmission Energy Savings through Adaptive Traffic Shaping Policies2014Independent thesis Basic level (degree of Bachelor), 10,5 credits / 16 HE creditsStudent thesis
    Abstract [en]

    This bachelor thesis will explore how two traffic shaping mechanisms can help preserve battery power while retaining a certain Quality of Service (QoS) in an Android based application developed for crisis management. The implemented user-space mechanisms will delay all elastic data requests in order to reduce the number of times the 3G transmission radio enters high power states. This lowers the QoS but extends the user equipment's battery life. The thesis will show that a shaping mechanism has the capability to reduce radio energy usage by up to 50% for the given Android application at the cost of added transmission delays by up to 134 seconds for background traffic. The study also presents two policies that help the application adapt to the current battery level and lower the QoS accordingly, namely one that has a lenient savings effect and one that has an aggressive savings effect.

  • 6.
    Furberg, Bibbi
    Linköping University, Department of Computer and Information Science.
    A better DREAM?: Utvärdering och utveckling av en metod för analys av olyckor inom biltrafikdomänen.2004Independent thesis Advanced level (degree of Magister)Student thesis
    Abstract [sv]

    Denna uppsats är en del av trafiksäkerhetsprojektet FICA (Factors Influencing the Causation of Accidents and Incidents), vars målsättning är att genom en förståelse för förarbeteende kunna utveckla aktiv säkerhetsteknologi för fordon. Inom detta projekt kommer en metod för olycksanalys, DREAM (Driving Reliability and Error Analysis Method), att användas. Den här uppsatsen handlar om att utvärdera och utveckla denna analysmetod. Arbetet med metoden har främst gällt användbarhetsaspekter av DREAM. Även olika kvalitetsaspekter som till exempel replikerbarhet, har undersökts. Arbetet har skett genom ett antal studier där DREAM tillämpats på olycksmaterial. DREAM har bland annat testats genom en kooperativ utvärdering där testpersonerna fick"tänka högt"medan de utförde analysen. Arbetet resulterade i vissa förändringar i den befintliga metoden, samt i en manual till DREAM och mallar att fylla i vid en analys.

  • 7.
    Felixon, William
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    A case study which aims to streamline Tretti's receiving process by improving the suppliers' delivery processes2016Independent thesis Basic level (degree of Bachelor), 12 credits / 18 HE creditsStudent thesis
    Abstract [sv]

    Tretti AB är ett e-handelsföretag som säljer produkter inom segmenten vitvaror, hushållsapparater, hem och trädgård, personvård, badrum samt sport och fritid. För företag som är verksamma inom e-handel innebär logistik flera konkurrensfaktorer. Kunderna kräver exempelvis låga leveranstider och framförallt att utlovade leveranstider hålls. Det finns även också goda möjligheter att bli kostnadseffektiv gentemot konkurrenter genom att hela tiden ligga i framkant och utveckla sitt logistiksystem.

    Ankomstprocessen är en kritisk process i ett företags logistikflöde. Främst p.g.a. att den är beroende av leverantörernas leveransprocesser. Undermålig leveransservice av leverantörerna kan leda till långdragna och kostsamma mottagningsprocesser hos kunderna.

    Tretti såg en potentiell utvecklingsmöjlighet i deras ankomstprocess. Som ett första steg i att försöka effektivisera ankomstprocessen ville Tretti undersöka möjligheterna att förbättra leverantörernas leveransservice. Syftet med denna studie är således att genom att skapa en förståelse för hur och på vilket sätt leverantörernas leveransservice påverkar Trettis ankomstprocess föreslå förbättringsförslag som ifall de implementeras leder till en effektivisering av ankomstprocessen.

    För att uppnå syftet behövdes en förståelse skapas för vilka aktiviteter som ingår i ankomstprocessen samt hur de förhåller sig till varandra. Detta gjordes genom att observera Trettis ankomstprocess. För att sedan få en förståelse för vilka aktiviteter i ankomstprocessen som påverkas av leverantörernas leveransservice gjordes intervjuer av anställda i godsmottagningen. En analys av både observationerna och intervjuerna resulterade i en lista med kritiska delar i ankomstprocessen. Om leverantörerna inte presterar tillräckligt bra i sin leveransservice påverkar det dessa kritiska delar negativt och det gör att ankomstprocessen blir långdragen och kostsam.

    Exempel på kritiska delar är ingen individuell kolliuppmärkning, layout på följesedel och leveranser utan följesedel. En jämförelse av två leveranser från två olika leverantörer gjordes under observationerna. En av leverantörerna arbetade med individuell kolliuppmärkning vilket resulterade i en bättre layout på följesedeln. Denna leverantör hade en individuell följesedel på varje kolli som specificerade vad den pallen eller kartongen innehöll. Den andra leverantören samlade hela leveransen i en gemensam följesedel vilket ledde till en lång och ostrukturerad följesedel. Vissa leveranser från denna leverantör hade en 18 sidor lång följesedel. Att en leverantör samlade hela leveransen i en följesedel innebar således att det inte specificerades vad varje individuellt kolli eller kartong innehöll. Jämförelsen visade att leveranserna från leverantören som arbetade med följesedlar som specificerade vad varje kartong eller pall innehöll resulterade i att ankomstprocessen blev effektivare, framförallt för att varje kolli kunde tas emot individuellt. Ankomstprocessen blev mer tidskrävande vid leveranser från leverantören som hade en följesedel per leverans bl.a. för att det krävdes att samtliga kollin i leveransen lokaliserades innan ankomstregistreringen kunde påbörjas, ibland upp emot 40 pallar, samt att det tog längre tid att para ihop en artikelrad på följesedeln med den fysiska artikeln.

    Sista steget för att uppfylla syftet blev att konkret formulera lösningsförslag som vid implementering leder till en effektivare ankomstprocess. Ett lösningsförslag föreslår en implementering av ett standardiserat system för företags värdekedjor utvecklat av den ickevinstdrivande organisationen GS1. Detta system ger varje individuellt kolli en streckkod som samlar information om kollit. Vid skanning av streckkoden kan information om vilka  artiklar kollit innehåller hämtas och syftet är att med detta system i större utsträckning standardisera Trettis ankomstprocess. Ett annat lösningsförslag är att formulera en kravspecifikation för samtliga leverantörer som tydligt klargör vad som förväntas av leverantörer till Tretti.

  • 8.
    Henningsson, Mathias
    et al.
    Linköping University, Department of Mathematics. Linköping University, The Institute of Technology.
    Holmberg, Kaj
    Linköping University, Department of Mathematics. Linköping University, The Institute of Technology.
    Rönnqvist, Mikael
    Linköping University, Department of Mathematics. Linköping University, The Institute of Technology.
    Värbrand, Peter
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    A column generation approach for a ring network design problem2003Report (Other academic)
    Abstract [en]

    When designing a telecommunication network, one often wish to include some kind of survivability requirement, for example that there should be at least two paths between every pair of nodes in the network. A design model who fulfills this requirement is a network build up with rings. The network design problem is to choose links from a given network, and compose them into a number of rings. The rings are connected to each other at certain transit nodes. The number of possible rings is enormous, and each possible ring is associated with a certain fixed cost. A ring has a fixed capacity, however, we model it as a linear cost depending on the traffic using the ring and the length of the ring. We describe the problem, and model it is a set covering model, where a column describes how a specific ring is used. Even with a small set of rings, number of possible columns in the model is large. Therefore, a column generation approach is used to solve the set covering model with a given set of rings. An important part of the problem is to generate new rings, were the dual solution from the set covering model gives rewards on the nodes, representing a nodes’ wish to be included in a new ring. The ring generation problem is a modification of a traveling salesman subtour problem. New rings are generated using a heuristic. We present some computational results for a real data network and a number of random generated networks.

  • 9.
    Björklund, Patrik
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Science and Technology.
    Värbrand, Peter
    Linköping University, The Institute of Technology. Linköping University, Department of Science and Technology.
    Yuan, Di
    Linköping University, The Institute of Technology. Linköping University, Department of Science and Technology, Communications and Transport Systems.
    A Column Generation Method for Spatial TDMA Scheduling in Ad Hoc Networks2004In: Ad hoc networks, ISSN 1570-8705, Vol. 2, no Issue 4, 405-418 p.Article in journal (Refereed)
    Abstract [en]

    An ad hoc network can be set up by a number of units without the need of any permanent infrastructure. Two units establish a communication link if the channel quality is sufficiently high. As not all pairs of units can establish direct links, traffic between two units may have to be relayed through other units. This is known as the multi-hop functionality. In military command and control systems, ad hoc networks are also referred to as multi-hop radio networks. Spatial TDMA (STDMA) is a scheme for access control in ad hoc networks. STDMA improves TDMA by allowing simultaneous transmission of multiple units. In this paper, we study the optimization problem of STDMA scheduling, where the objective is to find minimum-length schedules. Previous work for this problem has focused on heuristics, whose performance is difficult to analyze when optimal solutions are not known. We develop novel mathematical programming formulations for this problem, and present a column generation solution method. Our numerical experiments show that the method generates a very tight bound to the optimal schedule length, and thereby enables optimal or near-optimal solutions. The column generation method can be used to provide benchmarks when evaluating STDMA scheduling algorithms. In particular, we use the bound obtained in the column generation method to evaluate a simple greedy algorithm that is suitable for distributed implementations.

  • 10.
    Larsson, Torbjörn
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Mathematics, Optimization .
    Patriksson, Michael
    Matematiska vetenskaper Chalmers tekniska högskola.
    Rydergren, Clas
    Linköping University, The Institute of Technology. Linköping University, Department of Science and Technology.
    A column generation procedure for the side constrained traffic equilibrium problem2004Article in journal (Refereed)
    Abstract [en]

    We present a column generation procedure for the side constrained traffic equilibrium problem. A dual stabilization scheme is introduced to improve the computational performance. Computational experiments for the case of linear side constraints are presented. The test problems are well known traffic equilibrium instances where side constraints of link flow capacity type and general linear side constraints are added. The computational results are promising especially for instances with a relatively small number of side constraints.

  • 11.
    Hägglöf, Kristoffer
    et al.
    Linköping University, Department of Mathematics. Linköping University, The Institute of Technology.
    Lindgren, Per Olov
    Linköping University, Department of Mathematics. Linköping University, The Institute of Technology.
    A comment on some test networks for the traffic assignment problemManuscript (preprint) (Other academic)
    Abstract [en]

    We show that many published test problems for traffic assignment algorithms have peculiarities. First and foremost, several of them have incorrectly specified attributes, such as the number of nodes. In other test-problems, the network contains subnetworks with constant travel times; subnetworks which to a large extent can be reduced or eliminated. In further test problems, the constant travel time subnetworks imply that the solution has nonunique arc flows.

  • 12.
    Hildebrand, Cisilia
    et al.
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Hörtin, Stina
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    A comparative study between Emme and Visum with respect to public transport assignment2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Macroscopic traffic simulations are widely used in the world in order to provide assistance in the traffic infrastructure development as well as for the strategic traffic planning. When studying a large traffic network macroscopic traffic simulation can be used to model current and future traffic situations. The two most common software used for traffic simulation in Sweden today are Emme and Visum, developed by INRO respective PTV.

    The aim of the thesis is to perform a comparison between the software Emme and Visum with respect to the assignment of public transport, in other words how passengers choose their routes on the existing public transport lines. However, in order to make a complete software comparison the run-time, analysis capabilities, multi-modality, capacity to model various behavioural phenomena like crowding, fares etc. this will not be done in this comparison. It is of interest to study the differences between the two software algorithms and why they might occur because the Swedish Transport Administration uses Emme and the Traffic Administration in Stockholm uses Visum when planning public transport. The comparison will include the resulting volumes on transit lines, travel times, flow through specific nodes, number of boarding, auxiliary volumes and number of transits. The goal of this work is to answer the following objective: What are the differences with modelling a public transport network in Emme and in Visum, based on that the passengers only have information about the travel times and the line frequency, and why does the differences occur?

    In order to evaluate how the algorithms work in a larger network, Nacka municipality (in Stockholm) and the new metro route between Nacka Forum and Kungsträdgården have been used. The motivation for choosing this area and case is due to that it is interesting to see what differences could occur between the programs when there is a major change in the traffic network.

    The network of Nacka, and parts of Stockholm City, has been developed from an existing road network of Sweden and then restricted by "cutting out" the area of interest and then removing all public transportation lines outside the selected area. The OD-matrix was also limited and in order not to loose the correct flow of travellers portal zones was used to collect and retain volumes.

    To find out why the differences occur the headway-based algorithms in each software were studied carefully. An example of a small and simple network (consisting of only a start and end node) has been used to demonstrate and show how the algorithms work and why volumes split differently on the existing transit lines in Emme and Visum. The limited network of Nacka shows how the different software may produce different results in a larger public transport network.

    The results show that there are differences between the program algorithms but the significance varies depending on which output is being studied and the size of the network. The Visum algorithm results in more total boardings, i.e. more passengers have an optimal strategy including a transit. The algorithms are very similar in both software programs, since they include more or less parts of the optimal strategy. The parameters used are taken more or less into consideration in Emme and Visum. For example Visum will first of all focus on the shortest total travel time and then consider the other lines with respect to the maximum waiting time. Emme however, first focuses on the shortest travel time and then considers the total travel time for other lines with half the waiting time instead of the maximum wait time. This results in that less transit lines will be attractive in Emme compared to Visum. The thesis concludes that varying the parameters for public transport in each software algorithm one can obtain similar results, which implies that it is most important to choose the best parameter values and not to choose the "best" software when simulating a traffic network.

  • 13.
    Dang, Nguyen Thong
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Science and Technology.
    Tavanti, Monica
    Linköping University, The Institute of Technology. Linköping University, Department of Science and Technology.
    Rankin, Ivan
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Cooper, Matthew
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    A comparison of different input devices for a 3D environment2007In: European Conference on Cognitive Ergonomics 2007,2007, London: ACM Press , 2007, 153- p.Conference paper (Refereed)
    Abstract [en]

    Motivation - To identify a suitable interaction modality -among the ones currently implemented in a three-dimensional (3D) environment for Air Traffic Control- for allowing interactive exploration of and gathering information about 3D weather structures. Research approach - A usability study entailing four interaction modalities (also called -interaction interfaces-): voice, wand, pen and sketch interfaces, across a task requiring 3D surface exploration, information gathering and recall of information. Quantitative data (time, errors and a composite performance index) as well as qualitative data were collected. Findings/Design - Overall, the results indicate that the wand supported a better performance when compared to the other interaction interfaces. Among the four interaction interfaces, the voice interface seems to present additional limitations, mostly related to time lag in the voice recognition, that were judged as a source of frustration. Originality/Value - The present work provides empirical results deriving from a comparative usability study of four interaction interfaces; it contributes to the study of interaction in 3D environments with new empirical data.

  • 14.
    Thong Dang, Nguyen
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Tavanti, Monica
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Rankin, Ivan
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Cooper, Matthew
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    A comparison of different input devices for a 3D environment2009In: INTERNATIONAL JOURNAL OF INDUSTRIAL ERGONOMICS, ISSN 0169-8141, Vol. 39, no 3, 554-563 p.Article in journal (Refereed)
    Abstract [en]

    This paper presents a usability study comparing wand, voice, and two tablet-PC based interfaces across a task requiring three-dimensional surface exploration, information gathering and recall of information. The aim of this study was to identify a suitable interaction interface, among the ones implemented in a three-dimensional environment for Air Traffic Control, for interactive exploration of and gathering information about three-dimensional weather structures. Data concerning time, error rate, number of control actions as well as participants feedback on ease of learning, ease of use, frustration and perceived difficulty of the performed task were collected. The results indicate that the wand interface supported better performance when compared with the other interaction interfaces. Among the four interaction interfaces, the voice interface seems to present several limitations, mostly related to time lag in the voice recognition, which was judged by the subjects as a source of frustration.

  • 15.
    Falkmer, Torbjörn
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Neuroscience and Locomotion, Rehabilitation Medicine. Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Paediatric Habilitation Community Service.
    Gregersen, Nils-Petter
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Department of Health and Society, Division of Preventive and Social Medicine and Public Health Science.
    A comparison of eye movement behavior of inexperienced and experienced drivers in real traffic environments2005In: Optometry and Vision Science, ISSN 1040-5488, Vol. 82, no 8, 732-739 p.Article in journal (Refereed)
    Abstract [en]

    Purpose. The importance of the visual system as the input channel for sensory information necessary when driving is often stated. There are several reports on differences in visual search strategies between experienced and inexperienced drivers, as well as in relation to the roadway. However, the results are ambiguous and are not sampled by similar procedures. Based on previous findings, the aim of the present study was to gain further knowledge on these differences by testing the hypotheses that inexperienced drivers, in comparison to experienced drivers, fixate closer to the vehicle, fixate more often on in-vehicle objects, spread their fixations less along the horizontal meridian, fixate more often on relevant traffic cues, and fixate more often on objects classified as potential hazards. Methods. Data from eye-tracker recordings of visual search strategies of the driver in real-world traffic were used for the analyses. Results. The results confirmed all stated hypotheses regarding differences between inexperienced and experienced drivers, with the exception of fixations closer to the vehicle, in which ambiguous results were found. Conclusions. The present study provides normative data for the understanding of the development of visual search strategies among drivers. The methodology used in the present study, i.e., to combine a quantitative analysis with a qualitative analysis proved, to be useful to compare visual search strategies among inexperienced and experienced drivers. Copyright © 2005 American Academy of Optometry.

  • 16.
    Vogel, K
    Swedish Natl Rd & Transport Res Inst, S-58195 Linkoping, Sweden.
    A comparison of headway and time to collision as safety indicators2003In: Accident Analysis and Prevention, ISSN 0001-4575, Vol. 35, no 3, 427-433 p.Article in journal (Refereed)
    Abstract [en]

    The two safety indicators "headway" and "time to collision (TTC)" are discussed and compared with respect to their usefulness in determining the safety of different traffic situations, like different locations in a junction. Over a 6-day-period traffic flow measures were taken in a four-way junction with stop signs on the minor road. It was found that for vehicles in a car following situation headway and TTC are independent of each other. The percentage of small headways is relatively constant across different locations in the junction, while the percentage of small TTC values varies between different locations. It is recommended to use headway for enforcement purposes, because small headways generate potentially dangerous situations. TTC, on the other hand, should be used when a certain traffic environment is to be evaluated in terms of safety, because it indicates the actual occurrences of dangerous situations. (C) 2002 Elsevier Science Ltd. All rights reserved.

  • 17.
    Chuasomboon, Sasit
    Linköping University, Department of Electrical Engineering, Communication Systems. Linköping University, The Institute of Technology.
    A comparison of ranging and localization techniques in indoor, urban, and tunnel environments2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Localization in wireless network sensors is an attractive research area nowadays. It is widely used in many applications e.g., indoor/outdoor asset tracking, intrusion detection, search-and-rescue, road traffic monitoring, and water quality monitoring. An accuracy and robustness to noise are important issues for localization which is needed to study and research to find the best solution. This thesis compares a ranging and localization techniques in indoor, urban and tunnel through a high performance ray-tracing simulator, Wireless InSiteR . Ranging techniques are based on two standard distance related measurement schemes e.g., RSS and TOA. A linearized least squares technique with reference node selection approach is chosen to estimate unknown nodes positions. Indoor and urban area are built-in floor plan and terrain available in simulator program, while tunnel is designed. In general, localization accuracy suffers from multipath and NLOS condition. This thesis also observes characteristic of them from ray-tracing method perspective. Firstly, important simulation parameters such as number ofreflections/diffractions, types of waveform, and types of antenna are analyzed oneach environments. Then, the models for distance estimation based on RSS and TOA measurements are created using measurements in simulated environments. The thesis proposes four scenarios for distance estimation model. They are line-of-sight (LOS), non-line-of-sight (NLOS), combination of LOS and NLOS, and NLOS with obstacle. All four scenarios models are derived along with model error distribution to observe characteristic of noise due to multipath and NLOS condition. Finally, the localization using only LOS condition measurements, is tested on each environment and compared results in term of accuracy.

  • 18.
    Almkvist, Per
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    A comparison of two line capacity models for railway traffic2006Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    There are a lot of different factors that affect the capacity on our railways. The infrastructure is one important part but also the timetable and the mixture of trains affect the capacity. The performance on the stations is of course a very important part of the railway system. In this report line capacity models are studied and the purpose of the models is to estimate the capacity on the track between the stations. The models that are studied in the report are the UIC-model and Banverkets model for line capacity. The UIC-model is developed by the European organization with the name UIC and aim to create a more common interpretation of line capacity in central Europe. The model from Banverket is used to give a first indication when seeking problem areas in the railway system. Both models gives a percentage use of the capacity witch is calculated by dividing the time that the track is occupied with the time that is studied. Afterwards the capacity consumption is compared to predefined values that give information about the traffic situation on the line. Also the restore ability is being examined in the report. The measure is based on the delay situation on the specific line.

    The UIC-model is more complex compared to Banverkets model. The UIC-model demand more information that describes the infrastructure and the vehicles. Also the user needs a simulation program to get the necessary information about the reservations of the block sections. The model from Banverket is easier to use but at the same time not as clear as the UIC-model. There is an obvious relation between the models stronger and weaker sides and there purposes.

    The line capacity models and the restore ability are used in a case at the line between Uppsala – Myrbackan (north of Stockholm). Two timetables from the autumn of 2004 and the autumn of 2006 are used in the case. The weekdays that are studied are Tuesday, Wednesday and Thursday. The line is being used the most at the time between 07.00 and 09.00, this is the time that are studied in the case. The results from the case are a bit contradictory. The line capacity models indicated no overload, at the same time the restore ability shows that the mount of delays increases on the line.

  • 19.
    He, Qing
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering.
    A Comprehensive Analysis of Optimal Link Scheduling for Emptying a Wireless Network2016Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Wireless communications have become an important part of modern life. The ubiquitous wireless networks and connectivities generate exponentially increasing data traffic. In view of this, wireless network optimization, which aims at utilizing the limited resource, especially spectrum and energy, as efficiently as possible from a network perspective, is essential for performance improvement and sustainable development of wireless communications.

    In the dissertation, we focus on a fundamental problem of wireless network optimization, link scheduling, as well as its subproblem, link activation. The problem type arises because of the nature of wireless media and hence it is of relevance to a wide range of networks with multiple access. We freshen these classic problems up by novel extensions incorporating new technologies of interference management or with new performance metrics. We also revisit the problems in their classic setup to gain new theoretical results and insights for problem-solving. Throughout the study, we consider the problems with a general setup, such that the insights presented in this dissertation are not constrained to a specific technology or network type. Since link activation and scheduling are key elements of access coordination in wireless communications, the study opens up new approaches that significantly improve network performance, and eventually benefit practical applications.

    The dissertation consists of five research papers. The first paper addresses maximum link activation with cooperative transmission and interference cancellation. Papers II and III investigate the minimum-time link scheduling problem in general and a particular class of networks, respectively. In Paper IV, we consider the scheduling problem of emptying a network in its broad form and provide a general optimality condition. In Paper V, we study the scheduling problem with respect to age of information.

    List of papers
    1. Maximum Link Activation with Cooperative Transmission and Interference Cancellation in Wireless Networks
    Open this publication in new window or tab >>Maximum Link Activation with Cooperative Transmission and Interference Cancellation in Wireless Networks
    2017 (English)In: IEEE Transactions on Mobile Computing, ISSN 1536-1233, E-ISSN 1558-0660, Vol. 16, no 2, 408-421 p.Article in journal (Other academic) Published
    Abstract [en]

    We address the maximum link activation problem in wireless networks with new features, namely when the transmitters can perform cooperative transmission, and the receivers are able to perform successive interference cancellation. In this new problem setting, which transmitters should transmit and to whom, as well as the optimal cancellation patterns at the receivers, are strongly intertwined. We present contributions along three lines. First, we provide a thorough tractability analysis, proving the NP-hardness as well as identifying tractable cases. Second, for benchmarking purposes, we deploy integer linear programming for achieving global optimum using off-theshelf optimization methods. Third, to overcome the scalability issue of integer programming, we design a sub-optimal but efficient optimization algorithm for the problem in its general form, by embedding maximum-weighted bipartite matching into local search. Numerical results are presented for performance evaluation, to validate the benefit of cooperative transmission and interference cancellation for maximum link activation and to demonstrate the effectiveness of the proposed algorithm.

    Place, publisher, year, edition, pages
    IEEE, 2017
    National Category
    Communication Systems Telecommunications
    Identifiers
    urn:nbn:se:liu:diva-112447 (URN)10.1109/TMC.2016.2546906 (DOI)
    Conference
    2014 IEEE 25th Annual International Symposium on Personal, Indoor, and Mobile Radio Communications (PIMRC), September 2-5, Washington DC, DC, USA
    Note

    Funding agencies: Swedish Research Council; EU FP7 Marie Curie [324515, 329313]; National Science Foundation [CCF-0728966, CCF-1420651]; ONR [N000141410107]

    Available from: 2014-11-27 Created: 2014-11-27 Last updated: 2017-03-27Bibliographically approved
    2. Minimum-Time Link Scheduling for Emptying Wireless Systems: Solution Characterization and Algorithmic Framework
    Open this publication in new window or tab >>Minimum-Time Link Scheduling for Emptying Wireless Systems: Solution Characterization and Algorithmic Framework
    2014 (English)In: IEEE Transactions on Information Theory, ISSN 0018-9448, Vol. 60, no 2, 1083-1100 p.Article in journal (Refereed) Published
    Abstract [en]

    We consider a set of transmitter-receiver pairs, or links, that share a wireless medium and address the problem of emptying backlogged queues with given initial size at the transmitters in minimum time. The problem amounts to determining activation subsets of links, and their time durations, to form a minimum-time schedule. Scheduling in wireless networks has been studied under various formulations before. In this paper, we present fundamental insights and solution characterizations that include: 1) showing that the complexity of the problem remains high for any continuous and increasing rate function; 2) formulating and proving sufficient and necessary optimality conditions of two baseline scheduling strategies that correspond to emptying the queues using one-at-a-time or all-at-once strategies; and 3) presenting and proving the tractability of the special case in which the transmission rates are functions only of the cardinality of the link activation sets. These results are independent of physical-layer system specifications and are valid for any form of rate function. We then develop an algorithmic framework for the solution to this problem. The framework encompasses exact as well as sub-optimal, but fast, scheduling algorithms, all under a unified principle design. Through computational experiments, we finally investigate the performance of several specific algorithms from this framework.

    Place, publisher, year, edition, pages
    Institute of Electrical and Electronics Engineers (IEEE), 2014
    Keyword
    Algorithm; optimality; scheduling; wireless networks
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-104836 (URN)10.1109/TIT.2013.2292065 (DOI)000330286100022 ()
    Available from: 2014-02-28 Created: 2014-02-28 Last updated: 2016-09-15
    3. Polynomial Complexity Minimum-Time Scheduling in a Class of Wireless Networks
    Open this publication in new window or tab >>Polynomial Complexity Minimum-Time Scheduling in a Class of Wireless Networks
    2015 (English)In: IEEE Transactions on Control of Network Systems, ISSN 2325-5870, Vol. 3, no 3, 322-331 p.Article in journal (Other academic) Published
    Abstract [en]

    We consider a wireless network with a set of transmitter-receiver pairs, or links, that share a common channel, and address the problem of emptying finite traffic volume from the transmitters in minimum time. This, so called, minimum-time scheduling problem has been proved to be NP-hard in general. In this paper, we study a class of minimum-time scheduling problems in which the link rates have a particular structure. We show that global optimality can be reached in polynomial time and derive optimality conditions. Then we consider a more general case in which we apply the same approach and obtain an approximation as well as lower and upper bounds to the optimal solution. Simulation results confirm and validate our approach.

    Place, publisher, year, edition, pages
    Institute of Electrical and Electronics Engineers (IEEE), 2015
    Keyword
    algorithm, interference, optimality, scheduling, wireless networks
    National Category
    Communication Systems Telecommunications
    Identifiers
    urn:nbn:se:liu:diva-112446 (URN)10.1109/TCNS.2015.2512678 (DOI)
    Note

    At the time for thesis presentation publication was in status: Manuscript

    Available from: 2014-11-27 Created: 2014-11-27 Last updated: 2016-11-25Bibliographically approved
    4. A general optimality condition of link scheduling for emptying a wireless network
    Open this publication in new window or tab >>A general optimality condition of link scheduling for emptying a wireless network
    2016 (English)In: 2016 IEEE INTERNATIONAL SYMPOSIUM ON INFORMATION THEORY, IEEE , 2016, 1446-1450 p.Conference paper, Published paper (Refereed)
    Abstract [en]

    We consider link scheduling in wireless networks for emptying the queues of the source nodes, and provide a unified mathematical formulation that accommodates all meaningful settings of link transmission rates and network configurations. We prove that, any scheduling problem is equivalent to solving a convex problem defined over the convex hull of the rate region. Based on the fundamental insight, a general optimality condition is derived, that yields a unified treatment of optimal scheduling. Furthermore, we demonstrate the implications and usefulness of the result. Specifically, by applying the theoretical insight to optimality characterization and complexity analysis of scheduling problems, we can both unify and extend previously obtained results.

    Place, publisher, year, edition, pages
    IEEE, 2016
    Series
    IEEE International Symposium on Information Theory. Proceedings, ISSN 2157-8095, E-ISSN 2157-8117
    Keyword
    convex programming;radio links;radio networks;telecommunication scheduling;convex hull;convex problem;general optimality condition;link scheduling;link transmission rates;network configurations;optimal scheduling;source nodes;wireless network;Complexity theory;Information theory;Interference;Optimal scheduling;Processor scheduling;Scheduling;Wireless networks;complexity;optimality;scheduling;wireless networks
    National Category
    Computer Engineering Information Systems Software Engineering
    Identifiers
    urn:nbn:se:liu:diva-131357 (URN)10.1109/ISIT.2016.7541538 (DOI)000390098701102 ()
    Conference
    IEEE International Symposium on Information Theory (ISIT), 2016, Universitat Pompeu Fabra, Barcelona, Spain, July l0-l5, 2016
    Available from: 2016-09-15 Created: 2016-09-15 Last updated: 2017-01-30Bibliographically approved
  • 20.
    Yasar, Ansar-Ul-Haque
    et al.
    Linköping University, Department of Computer and Information Science.
    Jameel, Adeel
    Linköping University, Department of Computer and Information Science.
    A Computational Analysis of Driving Variations in a Distributed Simulated Driving Environment2007Independent thesis Basic level (professional degree), 20 points / 30 hpStudent thesis
    Abstract [en]

    This Master thesis report is the research conducted at the Linköping University (LiU) in the Cognitive Engineering group. This report describes and discusses the possible driving variations at T-intersections. In this study we tested how voice based command (GPS) system and traffic lights did influence the driving behavior. This computational study was conducted on a multi user driving simulation environment at Linköping University. A total of 12 groups each consisting of 4 persons participated in this study. The participants also completed a survey on paper with their valuable comments. To study the driving behavior we analyzed the conflict indicators at the Tintersection. We selected Post Encroachment Time (PET), speed and acceleration as good conflict indicators.

  • 21.
    Daneva, Maria
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Mathematics, Optimization .
    Lindberg, Per Olov
    Linköping University, The Institute of Technology. Linköping University, Department of Mathematics, Optimization .
    A Conjugate Direction Frank-Wolfe Method with Applications to the Traffic Assignment Problem2003In: Operations Research Proceedings 2002: Selected Papers of the International Conference on Operations Research (SOR 2002), Klagenfurt, September 2-5, 2002" / [ed] Leopold-Wildburger, U, Springer , 2003, -550 p.Chapter in book (Other academic)
    Abstract [en]

    This proceedings volume contains a selection of papers presented at the International Conference on Operations Research (SOR 2002).The contributions cover the broad interdisciplinary spectrum of Operations Research and present recent advances in theory, development of methods, and applications in practice. Subjects covered are Production, Logistics and Supply Chain Production, Marketing and Data Analysis, Transportation and Traffic, Scheduling and Project Management, Telecommunication and Information Technology, Energy and Environment, Public Economy, Health, Agriculture, Education, Banking, Finance, Insurance, Risk Management, Continuous Optimization, Discrete and Combinatorial Optimization, Stochastic and Dynamic Programming, Simulation, Control Theory, Systems Dynamics, Dynamic Games, Game Theory, Auctioning and Bidding, Experimental Economics, Econometrics, Statistics and Mathematical Economics, Fuzzy Logic, Multicriteria Decision Making, Decision Theory.

  • 22.
    Chisalita, Ioan
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Computer and Information Science, IISLAB - Laboratory for Intelligent Information Systems.
    Shahmehri, Nahid
    Linköping University, The Institute of Technology. Linköping University, Department of Computer and Information Science, IISLAB - Laboratory for Intelligent Information Systems.
    A context-based vehicular communication protocol2004In: IEEE Personal, Indoor and Mobile Radio Communication Symposium,2004, Barcelona, Spain: IEEE PIMRC , 2004, 2820- p.Conference paper (Refereed)
  • 23.
    Nilsson, Marcus
    et al.
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Westring, Alexander
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    A decision support system for an improved article placement2017Independent thesis Basic level (degree of Bachelor), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

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

  • 24.
    Hägglöf, Kristoffer
    et al.
    Linköping University, Department of Mathematics. Linköping University, The Institute of Technology.
    Lindberg, Per Olov
    Linköping University, Department of Mathematics. Linköping University, The Institute of Technology.
    A dual algorithm for the convex multicommodity flow problemManuscript (preprint) (Other academic)
    Abstract [en]

    This paper introduces a new dual ascent algorithm for solving the convex multicommodity flow problem, CMFP for short. CMFPs arize in many different routing problems such as the design of packet switched computer networks and the computation of traffic network equilibria. The algorithm utilizes the structure of the dual convex multicommodity flow problem, DCMFP for short. The dual objective is a sum of a concave differentiable function and a piecewise linear concave function. The algorithm exploits the local structure of the dual objective in an ascent scheme. In this paper a thorough explanation of the CMFPs and DCMFPs are given along with an outline of the dual ascent algorithm proposed. The method are applied to CMFPs arizing in the traffic assignment setting.

  • 25.
    Gustafsson, Josef
    et al.
    Linköping University.
    Overier, Gustaf
    Linköping University.
    Arlitt, Martin
    University of Calgary, Calgary, Canada.
    Carlsson, Niklas
    Linköping University, Department of Computer and Information Science, Database and information techniques. Linköping University, Faculty of Science & Engineering.
    A first look at the CT landscape: Certificate transparency logs in practice2017In: Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) / [ed] Uhlig S.,Amann J.,Kaafar M.A., 2017, Vol. 10176, 87-99 p.Conference paper (Refereed)
    Abstract [en]

    Many of today’s web-based services rely heavily on secure end-to-end connections. The “trust” that these services require builds upon TLS/SSL. Unfortunately, TLS/SSL is highly vulnerable to compromised Certificate Authorities (CAs) and the certificates they generate. Certificate Transparency (CT) provides a way to monitor and audit certificates and certificate chains, to help improve the overall network security. Using an open standard, anybody can setup CT logs, monitors, and auditors. CT is already used by Google’s Chrome browser for validation of Extended Validation (EV) certificates, Mozilla is drafting their own CT policies to be enforced, and public CT logs have proven valuable in identifying rogue certificates. In this paper we present the first large-scale characterization of the CT landscape. Our characterization uses both active and passive measurements and highlights similarities and differences in public CT logs, their usage, and the certificates they include. We also provide insights into how the certificates in these logs relate to the certificates and keys observed in regular web traffic.

  • 26.
    Olstam, Johan
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Lundgren, Jan
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Adlers, Mikael
    Swedish National Road and Transport Research Institute (VTI), VTI, SE-581 95 Linköping, Sweden.
    Matstoms, Pontus
    Swedish National Road and Transport Research Institute (VTI), VTI, SE-581 95 Linköping, Sweden.
    A Framework for Simulation of Surrounding Vehicles in Driving Simulators2008In: ACM Transactions on Modeling and Computer Simulation, ISSN 1049-3301, Vol. 18, no 3Article in journal (Refereed)
    Abstract [en]

    This article describes a framework for generation and simulation of surrounding vehicles in a driving simulator. The proposed framework generates a traffic stream, corresponding to a given target flow and simulates realistic interactions between vehicles. The framework is based on an approach in which only a limited area around the driving simulator vehicle is simulated. This closest neighborhood is divided into one inner area and two outer areas. Vehicles in the inner area are simulated according to a microscopic simulation model including advanced submodels for driving behavior while vehicles in the outer areas are updated according to a less time-consuming mesoscopic simulation model. The presented work includes a new framework for generating and simulating vehicles within a moving area. It also includes the development of an enhanced model for overtakings and a simple mesoscopic traffic model. The framework has been validated on the number of vehicles that catch up with the driving simulator vehicle and vice versa. The agreement is good for active and passive catch-ups on rural roads and for passive catch-ups on freeways, but less good for active catch-ups on freeways. The reason for this seems to be deficiencies in the utilized lane-changing model. It has been verified that the framework is able to achieve the target flow and that there is a gain in computational time of using the outer areas. The framework has also been tested within the VTI Driving simulator III.

  • 27.
    Tang, Ou
    Linköping University, Department of Production Economics.
    A Generalised Stockout Function for Continuous Production Variables2001In: Promet - Traffic - Trafico, ISSN 0353-5320, Vol. 13, no 6, 365-370 p.Article in journal (Refereed)
  • 28.
    Norin, Anna
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Science and Technology.
    Andersson, Tobias
    Linköping University, The Institute of Technology. Linköping University, Department of Science and Technology.
    Värbrand, Peter
    Linköping University, The Institute of Technology. Linköping University, Department of Science and Technology.
    Yuan, Di
    Linköping University, The Institute of Technology. Linköping University, Department of Science and Technology, Communications and Transport Systems.
    A GRASP Heuristic for Scheduling De-icing trucks at Stockholm Arlanda Airport2007In: 6th Eurocontrol Innovative Research Workshop and Exhibition,2007, 2007Conference paper (Other academic)
    Abstract [en]

    It is a fact that the most delays in the Air Transportation System (ATS) today occur at the airport. One reason for this is the large number of actors operating at the airport and the scarcity of communication between them and other parts of the ATS. Airport Logistics is a concept developed to survey all the flows of ehicles, people, material and information, which can be found on and around the airport. The objective is to increase efficiency, where one part is to decrease the delays. As an initial step, the turn-around process is analysed and an optimization model for the planning of de-icing trucks is implemented. The model shows that large savings can be made both by reducing the travelling distances for the trucks and reducing the delays the de-icing process is causing the ATS. However, most important is the advantage of having a plan for how the de-icing trucks should be utilized, something that is missing today.  

  • 29.
    He, Zhongxia
    et al.
    Chalmers, Sweden.
    Chen, Jingjing
    Chalmers, Sweden; Ericsson AB, Sweden.
    Svensson, Christer
    Linköping University, Department of Electrical Engineering, Integrated Circuits and Systems. Linköping University, The Institute of Technology.
    Bao, Lei
    Ericsson AB, Sweden.
    Rhodin, Anna
    Ericsson AB, Sweden.
    Li, Yinggang
    Ericsson AB, Sweden.
    An, Jianping
    Beijing Institute Technology, Peoples R China.
    Zirath, Herbert
    Chalmers, Sweden; Ericsson AB, Sweden.
    A Hardware Efficient Implementation of a Digital Baseband Receiver for High-Capacity Millimeter-Wave Radios2015In: IEEE transactions on microwave theory and techniques, ISSN 0018-9480, E-ISSN 1557-9670, Vol. 63, no 5, 1683-1692 p.Article in journal (Refereed)
    Abstract [en]

    This paper presents an implementation solution for a digital baseband receiver, which consists mainly of an analog symbol timing recovery (STR) block and a digital carrier recovery block. The STR is realized based on "one-sample-per-symbol" sampling, resulting in relaxed requirement on the A/D converters sampling speed. In this sense, the proposed implementation solution is hardware efficient. To functionally verify the solution, a proof-of-concept E-band link system is implemented and tested in the laboratory, which supports 5-Gbit/s data traffic using 16 quadrature amplitude modulation. The test results demonstrate that the proposed solution works for high-capacity millimeter-wave radios for point-to-point links, one of the targeted applications.

  • 30.
    Lundgren, Jan
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Peterson, Anders
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    A Heuristic for the Bilevel Origin–Destination Matrix Estimation Problem2008In: Transportation Research Part B: Methodological, ISSN 0191-2615, Vol. 42, no 4, 339-354 p.Article in journal (Refereed)
    Abstract [en]

    In this paper we consider the estimation of an origin–destination (OD) matrix, given a target OD-matrix and traffic counts on a subset of the links in the network. We use a general nonlinear bilevel minimization formulation of the problem, where the lower level problem is to assign a given OD-matrix onto the network according to the user equilibrium principle. After reformulating the problem to a single level problem, the objective function includes implicitly given link flow variables, corresponding to the given OD-matrix. We propose a descent heuristic to solve the problem, which is an adaptation of the wellknown projected gradient method. In order to compute a search direction we have to approximate the Jacobian matrix representing the derivatives of the link flows with respect to a change in the OD-flows, and we propose to do this by solving a set of quadratic programs with linear constraints only. If the objective function is differentiable at the current point, the Jacobian is exact and we obtain a gradient. Numerical experiments are presented which indicate that the solution approach can be applied in practice to medium to large size networks.

  • 31.
    Lundgren, Jan T.
    et al.
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Peterson, Anders
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Rydergren, Clas
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    A Heuristic for the Estimation of Time-Dependent Origin Origin–Destination Matrices from Traffic Counts2007In: Nordic MPS ’04, Norrköping, Sweden, October 21–23, 2004 and The 10th Jubilee Meeting of the EURO Working Group on Transportation, Poznan, Poland, September 13–16, 2005 and Transportforum, Linköping, Sweden, January 11–12, 2006, 2007Conference paper (Refereed)
  • 32.
    Lundgren, Jan
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Peterson, Anders
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Rydergren, Clas
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    A heuristic for the estimation of time-dependent origin-destination matrices from traffic counts2005In: Advanded OR an AI Methods in Transportation, Proceedings of the 10th Jubilee Meeting of the EURO Working Group on Transportation,2005, Poznan, Poland: Publishing House of Poznan University of Technology , 2005, 242- p.Conference paper (Refereed)
  • 33.
    Ekström, Joakim
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Science and Technology.
    Engelson, Leonid
    Centre for Traffic Research KTH.
    Rydergren, Clas
    Linköping University, The Institute of Technology. Linköping University, Department of Science and Technology.
    A heuristic method for finding congestion pricing schemes in transportation networks with modal choice2008In: International conference of Hong Kong society for transportation studies,2008 / [ed] Lo, HP; Leung, SCH; Tam, SML, Hong Kong, China: Hong Kong Society of Transportation Studies Ltd. , 2008, 773-782 p.Conference paper (Refereed)
    Abstract [en]

     In this paper we extend a previously developed heuristic procedure, with a modal choice model, to solve the congestion pricing problem of simultaneously finding the optimal number of toll facilities, their corresponding location and toll levels. When considering a congestion pricing scheme the cost of collecting the tolls can not be disregarded. The objective is where-fore to maximize the net social surplus, which is the social surplus minus the cost of collect-ing the tolls. The heuristic method is an iterative solution procedure, in which the integer part of the objec-tive function is approximated by a continuous function. A version of the Sioux Falls network (76 links) is used to demonstrate the solution procedure. The solution is a congestion pricing scheme which divide the network into four zones, by locating tolls on 27 links. This solution yields a social surplus which is only 13.5% lower than the marginal social cost pricing solu-tion. 

  • 34.
    Allström, Andreas
    et al.
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering.
    Ekström, Joakim
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering.
    Gundlegård, David
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering.
    Ringdahl, Rasmus
    Linköping University, Department of Science and Technology, Communications and Transport Systems.
    Rydergren, Clas
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering.
    Bayen, Alexandre M.
    Department of Civil and Environmental Engineering, University of California.
    Patire, Anthony D.
    Department of Civil and Environmental Engineering, University of California.
    A hybrid approach for short-term traffic state and travel time prediction on highways2016In: TRB 95th annual meeting compendium of papers, 2016Conference paper (Refereed)
    Abstract [en]

    Traffic management and traffic information are essential in urban areas, and require a good knowledge about both the current and the future traffic state. Both parametric and non-parametric traffic state prediction techniques have previously been developed, with different advantages and shortcomings. While non-parametric prediction has shown good results for predicting the traffic state during recurrent traffic conditions, parametric traffic state prediction can be used during non-recurring traffic conditions such as incidents and events. Hybrid approaches, combining the two prediction paradigms have previously been proposed by using non-parametric methods for predicting boundary conditions used in a parametric method. In this paper we instead combine parametric and non-parametric traffic state prediction techniques through assimilation in an Ensemble Kalman filter. As non-parametric prediction method a neural network method is adopted, and the parametric prediction is carried out using a cell transmission model with velocity as state. The results show that our hybrid approach can improve travel time prediction of journeys planned to commence 15 to 30 minutes into the future, using a prediction horizon of up to 50 minutes ahead in time to allow the journey to be completed.

  • 35.
    Carlsson, Niklas
    et al.
    Linköping University, Department of Computer and Information Science, Database and information techniques. Linköping University, The Institute of Technology.
    Dan, György
    KTH Royal Institute of Technology, Sweden.
    Arlitt, Martin
    NICTA, Australia.
    Mahanti, Anirban
    HP Labs, USA.
    A Longitudinal Characterization of Local and Global BitTorrent Workload Dynamics2012In: Passive and Active Measurement: 13th International Conference, PAM 2012, Vienna, Austria, March 12-14th, 2012. Proceedings / [ed] Nina Taft and Fabio Ricciato, Springer Berlin/Heidelberg, 2012, 252-262 p.Chapter in book (Refereed)
    Abstract [en]

    This book constitutes the refereed proceedings of the 13th International Conference on Passive and Active Measurement, PAM 2012, held in Vienna, Austria, in March 2012. <br>The 25 revised full papers presented were carefully reviewed and selected from 83 submissions. The papers were arranged into eight sessions traffic evolution and analysis, large scale monitoring, evaluation methodology, malicious behavior, new measurement initiatives, reassessing tools and methods, perspectives on internet structure and services, and application protocols.

  • 36.
    Kleiner, Alexander
    et al.
    University of Freiburg.
    Nebel, B.
    University of Freiburg.
    Ziparo, V.
    University of Freiburg.
    A Mechanism for Dynamic Ride Sharing based on Parallel Auctions2011In: 22th International Joint Conference on Artificial Intelligence (IJCAI), 2011, 266-272 p.Conference paper (Refereed)
    Abstract [en]

    Car pollution is one of the major causes of green- house emissions, and traffic congestion is rapidly becoming a social plague. Dynamic Ride Sharing (DRS) systems have the potential to mitigate this problem by computing plans for car drivers, e.g. commuters, allowing them to share their rides. Ex- isting efforts in DRS are suffering from the problem that participants are abandoning the system after repeatedly failing to get a shared ride. In this paper we present an incentive compatible DRS solution based on auctions. While existing DRS systems are mainly focusing on fixed assignments that minimize the totally travelled distance, the presented approach is adaptive to individual preferences of the participants. Furthermore, our system allows to tradeoff the minimization of Vehicle Kilometers Travelled (VKT) with the overall probability of successful ride-shares, which is an important feature when bootstrapping the system. To the best of our knowledge, we are the first to present a DRS solution based on auctions using a sealed-bid second price scheme.

  • 37.
    Gustafsson, Per-Ola
    et al.
    Linköping University, Department of Science and Technology.
    Ohlsson, Marcus
    Linköping University, Department of Science and Technology.
    A Menu-based Universal Control Protocol2002Independent thesis Basic level (professional degree)Student thesis
    Abstract [en]

    This thesis-project aims to research the possibilities of new wireless technologies in general control-situations. We have studied different existing control protocols, and developed a new protocol focusing on textbased menus. Our protocol is scaleable, easy to implement, and platform- and media independent. Since our protocol supports Plug and Play with dynamically allocated id’s, it does not require a unique id in the hardware.

    To test the protocol we have developed a prototype system, consisting of a mobile phone connected to a server, which in turn is connected to two slave units, controlling peripheral equipment on 220 Volt.

    The phone is an Ericsson T28, equipped with a Bluetooth unit. The server is runningthe real-time OS eCos on an ARM 7TDMI Evaluation Kit, and the slave units consist of two developer boards equipped with PIC-processors. Communication between the phone and the server is done over Bluetooth. However we did not find a working Bluetooth protocol stack ported to eCos, so a serial cable was used instead. Communication between the server and the slaves is done over a RS-485 serial network which simulates the traffic over a radio-network.

    The results show that our protocol is working, and that our system would be easy to implement, cheap to produce and very scalable.

  • 38.
    Trönnberg Lundin, André
    et al.
    Linköping University, Department of Management and Engineering. Linköping University, The Institute of Technology.
    Strömberg Jonzon, Sofie
    Linköping University, Department of Management and Engineering. Linköping University, The Institute of Technology.
    A method for calculating the carbon footprint at Volvo Logistics Corporation2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This thesis handles the need for Volvo Logistics (VLC) to calculate their total carbon footprint of purchased transportations, i.e. the total carbon dioxide emissions by all vehicles employed by VLC to transport the goods of their customers. The purpose of the thesis is therefore to determine a method with which VLC can calculate the total carbon footprint. To be able to decide upon one method that can fulfil the purpose, the authors searched for various methods, both in the academia and within the transportation sector, with which the emissions can be determined. Simultaneously the available input at VLC was studied to determine what type of method would be best suited to the current state of the company.

    After gathering several methods and determine what input was available and what was not available at VLC, an analysis of the found methods was done. First matching them with the available input to see which were usable as is, and then a more thorough Analytical Hierarchical Process analysis using three main-criterions; credibility, comparability, and simplicity, each with several sub-criterions. The weighting of these criterions was done in a workshop together with VLC employees, particularly the Environmental Manager and an Environmental Analyst, but also with two employees at the Global Logistics Development department at VLC. Using the weighting and the author’s comparisons of the methods within each of the criterions it was possible to obtain the methods with which further analysis should be done.

    After further analysis was conducted, considering VLC’s situation and possible development, the final methods was decided upon, one for each mode of transport; air, rail, road, and sea. These had to be adapted to better suit VLC and the input that was available; the distances, the weight, and the transport mode, factors which are incorporated in the methods recommended by the authors. The adaptation was then done using expertise at VLC to be able to determine what input VLC could affect as to be able to work towards lowering the total carbon footprint once it was calculated the first time. This also led to a revaluation of the method for sea transportation, forcing a change from the previously chosen one to a more suited method. This meant that three of the four modes; air, road, and sea, was covered by the NTM method, while rail used the Green Cargo method.

    While adapting the methods; to make them ready to use for VLC, certain changes required to obtain all the input needed was encountered and forwarded to the environmental department, letting them include it in the annual supplier survey.

    The thesis was concluded by four sets of instructions to be used to calculate the carbon footprint, one two tiered set for each mode of transportation. The instructions are presented in a step by step fashion of how to perform the calculations. The first part; First time usage, depicts those changes needed before the calculations can be attempted, the second part; Annual usage, cover those steps which has to be gone through every time the total carbon footprint for a period is to be calculated.

  • 39.
    Solinen, Emma
    et al.
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering. Trafikverket, Sundbyberg, Sweden.
    Nicholson, Gemma
    Birmingham Centre for Railway Research and Education, University of Birmingham, Unnited Kingdom.
    Peterson, Anders
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering.
    A Microscopic Evaluation of Robustness in Critical Points2017In: 7th International Conference on RailwayOperations Modelling and Analysis (RailLille 2017) / [ed] N. Tomii, I.A. Hansen, J. Rodriguez, P. Pellegrini, S. Dauzère-Pérès, D. De Almeida, International Association of Railway Operations Research , 2017, 83-103 p., 1705Conference paper (Refereed)
    Abstract [en]

    One method to increase the quality of railway traffic flow is to construct a more robust timetable in which trains are able to both recover from delays and the delays are prevented from propagating. Previous research results show that the indicator Robustness in Critical Points (RCP) can be used to increase timetable robustness. In this paper we present the use of a method for RCP optimization, how can be implemented and assessed ex-post via microscopic simulation and subsequently evaluated. From the evaluation we learn more about how increased RCP values influence a timetable’s performance. The aim is to understand more about RCP increase at a localised level within a timetable in terms of effects to the pairs of trains that are part of the indicator. We present a case study where an initial timetable and a timetable with increased RCP values are evaluated. The ex-post evaluation includes the quantification of measures concerning train-borne delay and robustness of traffic flow, as well as measures capturing the subsequent quality of service experienced by passengers to assess the broader effects of improved robustness. The result shows that it is necessary to use several Key Performance Indicators (KPIs) to evaluate the effects of an RCP increase. The robustness will increase at a localised level, but the results also indicate that there is a need to analyse the relationship between ex-post measures and RCP further, to improve the method used to increase RCP and thus its overall effect on timetable robustness.

  • 40.
    Ekström, Joakim
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    A MILP approximation approach for finding optimal toll locations and levels in elastic demand traffic networks2010In: TRANSPORTATION AND URBAN SUSTAINABILITY: Proceedings of the 15th International Conference of Hong Kong Society for Transportation Studies (HKSTS) / [ed] Sumalee, A; Lam, WHK; Ho, HW; Siu, B, Hong Kong, China: Hong Kong Society for Transportation Studies , 2010, 107-114 p.Conference paper (Refereed)
    Abstract [en]

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

  • 41.
    Sahlén, Viktoria
    et al.
    Linköping University, Department of Management and Engineering, Logistics & Quality Management.
    Daberius, Jessica
    Linköping University, Department of Management and Engineering, Logistics & Quality Management.
    A model based on total cost and manufacturer performance to evaluate a product as well as possible cost reductions2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Omega Pharma is a distributer of over the counter products, selling thousands of products produced at more than 200 manufacturers and sold in most European countries. The company was founded in Belgium in 1987 and has since then had a high market focus and expanded through acquisitions of brands and products. The company has in recent years started working towards centralization and supplier base management. A project team has been set up to work strategically by choosing key manufacturers and by reducing the supplier base. A first step in this is to look more closely at products with a low turnover and that are not strategically important in order to evaluate if the product is profitable and which products that could be moved to other manufacturers or cancelled from the portfolio. Therefore the purpose of the study is to:

    Create an evaluation model based on revenue, total cost and manufacturer performance to evaluate a product and if cost reductions can be achieved by ending the production of the product or moving the product to a different manufacturer.

    A four step approach for analyzing total cost was followed in order to, in a structured way, create the model and identify the relevant elements related to revenue, total cost and manufacturer performance that were to be present in the model. The four steps were:

    1. In a first step elements and costs were identified that might be relevant for the model. This was done based on previous research, holding interviews at the company and reviewing documents.
    2. The second step was to adapt the elements to the model.
    3. In the third step, it was decided how the elements and costs that were to be in the model would be calculated and presented as well as looking into how the model would be built.
    4. The fourth step consisted of doing test runs and a sensitivity analysis to test the robustness of the model.

    The result handed over to the company is in the form of the evaluation model created based on the above stated purpose. Within the model, there are 4 manufacturer performance parameters and 1 for revenue. When it comes to costs, the amount varies depending on the case analyzed. To evaluate product profitability there are 7 cost elements containing 20 identified costs. When evaluating moving a product to another manufacturer there are the same costs, however an additional element for transfer is added containing 5 costs. For the situation ending a production, there are 2 costs. In order to facilitate the use of the model, estimations were done to the costs to the extent possible. From test runs the model was further adapted to the company as it was identified what values connected to a product where possible for the user to find in the system and in what units of measure. The sensitivity analyses showed that none of the estimated values would, if the estimation was not accurate, affect the evaluation of the product. They could however affect the cost element of that cost.

  • 42.
    Strömgren, Per
    et al.
    Division of Transport planning, Economics and Engineering, Royal Institute of Technology (KTH), Stockholm, Sweden.
    Olstam, Johan
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering. Swedish National Road and Transport Research Institute (VTI), Linköping, Sweden.
    A Model for Capacity Reduction at Roadwork Zone2016In: International Symposium on Enhancing Highway Performance (ISEHP), (7th International Symposium on Highway Capacity and Quality of Service, 3rd International Symposium on Freeway and Tollway Operations), Elsevier, 2016, Vol. 15, 245-256 p.Conference paper (Refereed)
    Abstract [en]

    This paper presents an investigation of capacity reduction in connection with roadwork zones. The paper presents a state-of-the-art description on roadwork effects on capacity. Based on the literature on this topic the most important parameters that should be incorporated in a Swedish capacity manual for the operation and maintenance roadwork are: the proportion of heavy traffic; lane width; number of closed lanes; closed road shoulder; proportion of commuter traffic; and length of roadwork zone. The paper presents a comparison of a composite model of correction factors from Germany, USA and Denmark and the Dutch model for computation of capacity reduction. The comparison show that the two models essentially gives the same results. Based on these results a model was developed. The model developed was validated using empirical data from a full scale test at the motorway network in Gothenburg. The throughput was measured in two cases during the morning and afternoon peak hour. The capacity for the normal site conditions was estimated based on traffic flow and speed data from the same site. The result shows that the empirically estimated capacity reduction is consistent with the reduction calculated with the new model for the different road work designs evaluated. The conclusion is that the model developed seems to be valid for capacity reduction estimations of roadworks on Swedish motorways but that more empirics are needed to ensure general validity.

  • 43.
    Olstam, Johan
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    A model for simulation and generation of surrounding vehicles in driving simulators2005Licentiate thesis, monograph (Other academic)
    Abstract [en]

    Driving simulators are used to conduct experiments on for example driver behavior, road design, and vehicle characteristics. The results of the experiments often depend on the traffic conditions. One example is the evaluation of cellular phones and how they affect driving behavior. It is clear that the ability to use phones when driving depends on traffic intensity and composition, and that realistic experiments in driving simulators therefore has to include surrounding traffic.

    This thesis describes a model that generates and simulates surrounding vehicles for a driving simulator. The proposed model generates a traffic stream, corresponding to a given target flow and simulates realistic interactions between vehicles. The model is built on established techniques for time-driven microscopic simulation of traffic and uses an approach of only simulating the closest neighborhood of the driving simulator vehicle. In our model this closest neighborhood is divided into one inner region and two outer regions. Vehicles in the inner region are simulated according to advanced behavioral models while vehicles in the outer regions are updated according to a less time-consuming model. The presented work includes a new framework for generating and simulating vehicles within a moving area. It also includes the development of enhanced models for car-following and overtaking and a simple mesoscopic traffic model.

    The developed model has been integrated and tested within the VTI Driving simulator III. A driving simulator experiment has been performed in order to check if the participants observe the behavior of the simulated vehicles as realistic or not. The results were promising but they also indicated that enhancements could be made. The model has also been validated on the number of vehicles that catches up with the driving simulator vehicle and vice versa. The agreement is good for active and passive catch-ups on rural roads and for passive catch-ups on freeways, but less good for active catch-ups on freeways.

  • 44.
    Strömgren, Per
    et al.
    Department of Transportation and Logistics (ToL), Stockholm, Sweden.
    Olstam, Johan
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering.
    Tapani, Andreas
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering.
    A Model for Traffic Simulation of Flared Rural Road Intersections2015In: Transportation Research Procedia, ISSN 2352-1465, Vol. 6, no 2015, 239-258 p.Article in journal (Refereed)
    Abstract [en]

    This paper presents a micro-simulation model that takes flared design of rural intersections into consideration. The intersection model is designed with input parameters that describe the geometric conditions of the flare. The behavior model includes both a traditional gap-acceptance sub-model and a passage model for modelling of vehicles’ possibility to pass other vehicles using the flare. The intersection model developed has been implemented in the traffic micro simulation model RuTSim. The gap-acceptance part of the model has been calibrated using data for stop and yield 3-way intersections. The validation was performed by using video recordings to calculate delay for the yield regulated intersection and time in queue and service time for the stop regulated intersection. The results from the validation simulations correspond well with the empirical validation data. The effect of the flare on delay has been studied by using 3 different intersection lay-outs and different levels of minor and major flow. The result shows that the delay is decreasing with increasing intersection radius.

  • 45.
    Huang, Yu-Hsing
    Linköping University, Department of Computer and Information Science, CSELAB - Cognitive Systems Engineering Laboratory. Linköping University, The Institute of Technology.
    A Model of Human-Machine Interaction for Risk Analysis in Road Traffic: A Cognitive Systems Engineering Approach2006In: Proceedings of the 7th Asia-Pacific Conference on Computer Human Interaction, 2006Conference paper (Other academic)
  • 46.
    Granström, Karl
    et al.
    Linköping University, Department of Electrical Engineering. Linköping University, Faculty of Science & Engineering.
    Reuter, Stephan
    University of Ulm, Germany.
    Meissner, Daniel
    University of Ulm, Germany.
    Scheel, Alexander
    University of Ulm, Germany.
    A multiple model PHD approach to tracking of cars under an assumed rectangular shape2014In: 2014 17TH INTERNATIONAL CONFERENCE ON INFORMATION FUSION (FUSION), IEEE , 2014Conference paper (Refereed)
    Abstract [en]

    This paper presents an extended target tracking method for tracking cars in urban traffic using data from laser range sensors. Results are presented for three real world datasets that contain multiple cars, occlusions, and maneuver changes. The cars shape is approximated by a rectangle, and single track steering models are used for the target kinematics. A multiple model approach is taken for both the dynamics modeling and the measurement modeling. A comparison to ground truth shows that the estimation errors are generally very small: on average the absolute error is less than half a degree for the heading. Multiple cars are handled using a multiple model PHD filter, where a variable probability of detection is integrated to enable tracking of occluded cars.

  • 47.
    Koschorrek, Philipp
    et al.
    Linköping University, Department of Electrical Engineering, Computer Vision. Linköping University, The Institute of Technology.
    Piccini, Tommaso
    Linköping University, Department of Electrical Engineering, Computer Vision. Linköping University, The Institute of Technology.
    Öberg, Per
    Linköping University, Department of Electrical Engineering, Computer Vision. Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Felsberg, Michael
    Linköping University, Department of Electrical Engineering, Computer Vision. Linköping University, The Institute of Technology.
    Nielsen, Lars
    Linköping University, Department of Electrical Engineering, Vehicular Systems. Linköping University, The Institute of Technology.
    Mester, Rudolf
    Linköping University, Department of Electrical Engineering, Computer Vision. Linköping University, The Institute of Technology. University of Frankfurt, Germany.
    A multi-sensor traffic scene dataset with omnidirectional video2013In: 2013 IEEE CONFERENCE ON COMPUTER VISION AND PATTERN RECOGNITION WORKSHOPS (CVPRW), IEEE conference proceedings, 2013, 727-734 p.Conference paper (Refereed)
    Abstract [en]

    The development of vehicles that perceive their environment, in particular those using computer vision, indispensably requires large databases of sensor recordings obtained from real cars driven in realistic traffic situations. These datasets should be time shaped for enabling synchronization of sensor data from different sources. Furthermore, full surround environment perception requires high frame rates of synchronized omnidirectional video data to prevent information loss at any speeds.

    This paper describes an experimental setup and software environment for recording such synchronized multi-sensor data streams and storing them in a new open source format. The dataset consists of sequences recorded in various environments from a car equipped with an omnidirectional multi-camera, height sensors, an IMU, a velocity sensor, and a GPS. The software environment for reading these data sets will be provided to the public, together with a collection of long multi-sensor and multi-camera data streams stored in the developed format.

  • 48.
    Eriksson, Olle
    Linköping University, Department of Mathematics, Statistics. Linköping University, Faculty of Arts and Sciences.
    A new program for fast emission calculations based on the COPERT III modelManuscript (Other academic)
    Abstract [en]

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

  • 49.
    Chisalita, Ioan
    et al.
    Linköping University, Department of Computer and Information Science, IISLAB - Laboratory for Intelligent Information Systems. Linköping University, The Institute of Technology.
    Shahmehri, Nahid
    Linköping University, Department of Computer and Information Science, IISLAB - Laboratory for Intelligent Information Systems. Linköping University, The Institute of Technology.
    A novel architecture for supporting vehicular communication2002In: IEEE 56th Vehicular Technology Conference, 2002, 1002-1006 p.Conference paper (Refereed)
    Abstract [en]

    In today's world, traffic safety is a major problem. Traffic accidents result in more than half a million casualties each year and are associated with serious injuries and extensive material losses. Therefore, special attention is given to those technologies that can reduce the number and severity of road events. Inter-vehicle communication (IVC) and vehicle to road communication (VRC) are considered to have extensive potential for the development of efficient safety systems installed in vehicles. This paper proposes a novel, safety-oriented communication platform dedicated to supporting the exchange of safety-relevant information between traffic participants. The vehicular communication platform (VCP) aims to support a specific vehicular communication mechanism previously designed by the authors and briefly presented in the paper.

  • 50.
    Andersson Granberg, Tobias
    et al.
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering.
    Polishchuk, Tatiana
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering.
    Polishchuk, Valentin
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering.
    Schmidt, Christiane
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering.
    A Novel MIP-based Airspace Sectorization for TMAs2017Conference paper (Refereed)
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