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  • 1051.
    Weinholt, Åsa
    et al.
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Andersson Granberg, Tobias
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Evaluation of enhanced collaboration between fire and rescue services and security officers2013In: Proceedings of the 10th International ISCRAM Conference / [ed] T. Comes, F. Fiedrich, S. Fortier, J. Geldermann, T. Müller, 2013, p. 735-740Conference paper (Refereed)
    Abstract [en]

    The hypothesis of this study is that collaboration between fire and rescue services and new actors, with basic rescue skills, might be a cost effective way to improve emergency response. Interview studies of collaborations between fire and rescue services and security officers in three Swedish municipalities are presented. Seven semi-structured interviews are conducted with representatives from the security officer companies, the fire and rescue services and security managers at the municipalities. The method used to evaluate the collaborations quantitatively is Cost-benefit analysis. The collaborations have positive economic effects for society that most likely outweighs the costs. There also exist several external effects that are not possible to value monetarily, but that represent positive values for society. The results and their generalizability are discussed, as well as the possibility for these new collaborations to improve crisis management.

  • 1052.
    Weinholt, Åsa
    et al.
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Andersson, Tobias
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    New collaborations in daily emergency response: Applying cost benefit analysis to new first response initiatives in the Swedish fire and rescue service2015In: International Journal of Emergency Services, ISSN 2047-0894, E-ISSN 2047-0908, Vol. 4, no 2, p. 177-193Article in journal (Refereed)
    Abstract [en]

    Purpose

    – The purpose of this paper is to analyse costs and benefits from new collaborations in daily emergency response and to demonstrate how cost-benefit analysis (CBA) can be used for evaluating effects from these kinds of collaborations.

    Design/methodology/approach

    – CBA is used to evaluate two collaborations. The cases are: security officers that respond to fire and rescue service (FRS) calls; and home care nurses that assist the FRSs when they respond to urgent medical calls. Interviews, public documents and incident reports have been used as sources of data.

    Findings

    – Most costs are relatively straightforward to estimate. More difficult to estimate are the turn-out costs, including the services that cannot be performed when the new actors take on new assignments. One important benefit from these kinds of collaborations is reduced response time. Other benefits include increased situational awareness and improved preventive work in Case 1, as well as improved working conditions for the traditional resources and increased medical competence in Case 2. The analysis indicate that the case with the security officers most likely was socially beneficial, while the case with the home care nurses at the time of the study was not.

    Originality/value

    – The authors provide a thorough description and analysis of two interesting new ways of performing daily emergency response. Furthermore, the authors depict how CBA can be used to structure the analysis and evaluation of new initiatives in emergence services and how it can be used for identifying improvement potential. The authors also identify and discuss what is needed in terms of documentation as well as research, for it to be possible to improve the quantitative analysis of these kinds of initiatives

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  • 1053.
    Weinholt, Åsa
    et al.
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Holmgren, Johan
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Evaluating the effects of organizational changes and private sector involvement on cost efficiency in fire and rescue services2014Conference paper (Other academic)
  • 1054.
    Weinholt, Åsa
    et al.
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Holmgren, Johan
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    The Influence of Organizational Changes on Cost Efficiency in Fire and Rescue ServicesManuscript (preprint) (Other academic)
    Abstract [en]

    Fire and rescue services in Sweden have recently undergone organizational changes aiming at improving service quality and efficiency. Among those changes are an increased number of formalized cooperations between FRSs in neighboring municipalities, increased collaboration with other sectors in day-to-day operations, changes in the structure of rescue teams, and an increase in the tasks performed by the services. The purpose of this study was to evaluate whether these policy changes have resulted in increased cost efficiency in the Swedish FRS. We used stochastic frontier analysis of annual data from 2009 to 2012 for 205 Swedish municipalities, taking into account the relevant differences in conditions among them. The conclusion is that there is no evidence to be found of improved efficiency in the FRS. The policy changes that have been implemented have not had the desired effects, and most of the policy variables tested for inclusion in the model were not found significant. Recommendations for future research are to further investigate why these policy changes have not yet given the expected results, to examine how and if collaboration with different types of organizations (public, private and non-profit) affects efficiency differently and to make further in-depth comparisons between the most efficient and least efficient FRSs for there are great variations between them.

  • 1055.
    Wen, Keyao
    Linköping University, Department of Science and Technology, Communications and Transport Systems.
    Traffic Accident Prediction Model Implementation in Traffic Safety Management2009Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    As one of the highest fatalities causes, traffic accidents and collisions always requires a large amounteffort to be reduced or prevented from occur. Traffic safety management routines therefore always needefficient and effective implementation due to the variations of traffic, especially from trafficengineering point of view apart from driver education.Traffic Accident Prediction Model, considered as one of the handy tool of traffic safety management,has become of well followed with interested. Although it is believed that traffic accidents are mostlycaused by human factors, these accident prediction models would help from traffic engineering point ofview to enlarge the traffic safety level of road segments. This thesis is aiming for providing a guidelineof the accident prediction model implementation in traffic safety management, regarding to trafficengineering field. Discussion about how this prediction models should merge into the existing routinesand how well these models would perform would be given. As well, cost benefit analysis of theimplementation would be at the end of this thesis. Meanwhile, a practical field study would bepresented in order to show the procedures of the implementation of traffic accident prediction model.The field study is about this commercial model set SafeNET, from TRL Limited UK, implemented inRoad Safety Audit procedures combined with microscopic simulation tool. Detailed processing andinput and output data will be given accompany with the countermeasures for accident frequencyreduction finalization.

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    FULLTEXT02
  • 1056.
    Wennström, Jonas
    Linköping University, Department of Science and Technology, Communications and Transport Systems.
    Estimations of Delay Costs caused by Roadworks2010Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    When roadworks are performed, one of the impacts is delays in the traffic. Partly because of reduced speed limits past the work zones but mainly because of the facility's limited quality of service. This could result in significant delays for the road users with lost work and spare time as a consequence. The lost time in congestions could have been used more efficiently. It is therefore of interest to estimate these delays for different types of roadworks to calculate its macro economical impact. The estimations may be a factor in different types of planning, for example in roadwork planning, in work zone scheduling or in life cycle assessments.

    The estimations can be conducted using different methods, such as analytical, queuing theory or macrosimulation. However, to include the details of specific work zones an analysis method of higher detail is required. First to include varying geometric details, secondly due to the higher level of detail in the representation of the traffic. Therefore may microsimulation be a suitable analysis method. The purpose of this master thesis was to investigate microsimulations suitability for work zone analysis, by using the software AIMSUN.

    AIMSUN were different work zone types modeled, first of highways. Later was a 2-lane road modeled for which the traffic control was a fixed signal, then controlled by a simpler extension developed in C++ that simulated a flagger control.

    Using a developed helper program, the work zone models could be simulated for a large set of daily flow levels and heavy vehicle ratios. Together with corresponding results for normal conditions, it was possible to calculate the delays. The results were relationships between the total delays, for various heavy vehicle ratios.

    A concern with the results was deviations of the delays for different daily flows and heavy vehicle ratios. Even if the deviations will not have any greater impact on the total cost, they may be unwanted in decision models. Processing of the result may therefore be necessary.

    This master thesis has showed that microsimulation may be a suitable method to analyze work zone impacts. Using the high level of detail, work zones special character can be captured. Possible future work is to improve the reliability of results by performing validations of results with real work zone data to compare speeds, headways and queue lengths. Additional work may include to consider the diversion delays.

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    EstiDelayCosts
  • 1057.
    Wernberg, Max
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering.
    Security and Privacy of Controller Pilot Data Link Communication2018Independent thesis Basic level (degree of Bachelor), 10,5 credits / 16 HE creditsStudent thesis
    Abstract [en]

    Newly implemented technologies within the aviation lack, according to recent studies, built in security measures to protect them against outside interference. In this thesis we study the security and privacy status of the digital wireless Controller Pilot Data Link Communication (CPDLC) used in air traffic management alongside other systems to increase the safety and traffic capacity of controlled airspaces. The findings show that CPDCL is currently insecure and exposed to attacks. Any solutions to remedy this must adhere to its low levels of performance. Elliptical Curve Cryptography, Protected ACARS and Host Identity Protocol have been identified as valid solutions to the system’s security drawbacks and all three are possible to implement in the present state of CPDLC.

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    Security and Privacy of Controller Pilot Data Link Communication
  • 1058.
    Wernersson, Emil
    et al.
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Wiksborg, Tim
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Evaluation of measures to deal with space constraints in BillerudKorsnäs finished goods inventory in Skärblacka.2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Denna studie genomfördes på BillerudKorsnäs bruk i Skärblacka och undersökte hur utrymmesbegränsningar i ett färdigvarulager kan hanteras med olika åtgärder. Bakgrunden till studien är att färdigvarulagret i BillerudKorsnäs bruk i Skärblacka redan i dagsläget, när denna studie genomfördes, upplever en hög belastning på grund av en begränsad lagringsyta. Detta är dock hanterbart i dagsläget men i början av 2018 ska en ny pappersmaskin (PM10) implementeras. Detta kommer att medföra en ökad produktion av MG produkter som är de mest svårhanterliga produkterna. Därmed förväntas det att färdigvarulagret överbelastas om inga åtgärder vidtas. Inledningsvis i denna studie presenterade BillerudKorsnäs ett tjugotal åtgärder och av dessa åtgärder valdes åtta åtgärder ut i samråd med BillerudKorsnäs, som vidare kallas för det planerade åtgärdspaketet. De åtta åtgärderna är: lastbilspendel mellan Skärblacka och Norrköpings hamn (Pampus och Öhmansterminalen), ny lagerindelning, flytta all avsalumassa till Pampus, konsolidering av terminaler, alla översjötransporter av MG produkter går via Pampus, en extra ledtidsdag för direktlastbilar, utökad bemanning i magasinet och dokumenterade rutiner för ”onödig” lagring. Studiens syfte är därmed att utvärdera om det planerade åtgärdspaketet är en hållbar lösning för att hantera utrymmesbegränsningarna i färdigvarulagret när PM10 är i drift. För att analysera det planerade åtgärdspaketet skapades två simuleringsmodeller i simuleringsprogrammet Arena. En modell med PM10 och det planerade åtgärdspaketet och en modell med enbart PM10 för att kunna jämföra och analysera effekten av åtgärdspaketet. Analyserna tyder på att färdigvarulagret kommer att överbelastas om inga åtgärder vidtas. Samtidigt tyder analyserna också på att det planerade åtgärdspaketet är en hållbar lösning på de förväntade lagringsproblemen när PM10 är i drift. Vidare indikerade analyserna att andelen lastbilstransporter relativt tågtransporter kommer att öka när PM10 är i drift och att antalet lastbilstransporter per dag har en stor påverkan på lagernivåerna.

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    Evaluation of measures to deal with space constraints in BillerudKorsnäs finished goods inventory in Skärblacka.
  • 1059.
    Widler, Martina
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Survey and efficiency study of support- and spare parts inventory at Fiskeby Board in Norrköping2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Pappersbruket Fiskeby Board som är placerat i Norrköping tillverkar kartong av 100% returfibrer. Bruket har tillverkat papper i flera århundranden och är en av Europas äldsta tillverkare av papper och kartong. På pappersbruket finns ett underhålls- och reservdelslager som bistår med artiklar till hela företaget. Målet med studien är att ta fram förslag till hur förrådshanteringsprocessen kan förbättras för att göra den mer effektiv. Studien resulterade i 25 stycken förbättringsförslag, dessa förslag delades upp i två delar, de förbättringsförslag som kunde implementeras direkt och de som behövde vidare undersökningar. Vissa förslag täcker flera möjligheter och problem och andra förslag täcker bara ett. Lika så kan ett problem ha flera möjliga förbättringsförslag för att lösa dem. Även förbättringar i from av nya instruktioner där hela aktiviteter är inkluderade har föreslagits.

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    Survey and efficiency study of support- and spare parts inventory at Fiskeby Board in Norrköping
  • 1060.
    Wiklund, Mats
    et al.
    Transport Analysis, Stockholm, Sweden.
    Carlsson, Arne
    Swedish National Road and Transport Research Institute (VTI), Linköping, Sweden.
    Eriksson, Olle
    Swedish National Road and Transport Research Institute (VTI), 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 (VTI), Linköping, Sweden.
    Tapani, Andreas
    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.
    Effects of desired speeds for queuing and delay on single-lane road segments2015In: Transportmetrica A: Transport Science, ISSN 2324-9935, Vol. 11, no 8, p. 716-728Article in journal (Refereed)
    Abstract [en]

    To improve road safety on parts of the road network carrying low traffic volumes, road designs are proposed including single-lane road segments and periodic overtaking lanes. These roads have been proven to contribute to substantial benefits in terms of road safety. However, overtaking of slower vehicles is only possible on segments including an overtaking lane and not on the single-lane road segments. Driver and vehicle heterogeneity resulting in differences in desired speeds are consequently decisive for the traffic performance. Sufficient quality of service is relying on an appropriate design and distribution of single-lane segments and overtaking lanes. In this paper, we study the effect of the desired speed distribution on traffic performance on single-lane road segments. Expressions are derived for the travel time, delay and percent time spent following. The derived expressions link the desired speed distribution, the single-lane segment length and the traffic flow to the resulting traffic performance. The results are verified through comparison with measures based on microscopic traffic simulation. The conclusion is that there is a good agreement between derived measures and simulation results. The derived measures should therefore not only be of theoretical interest, but also of practical use to estimate traffic performance on single-lane road segments.

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  • 1061.
    Wiren, Jakob
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Data Storage Cost Optimization Based on Electricity Price Forecasting with Machine Learning in a Multi-Geographical Cloud Environment2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    As increased demand of cloud computing leads to increased electricity costs for cloud providers, there is an incentive to investigate in new methods to lower electricity costs in data centers. Electricity price markets suffer from sudden price spikes as well as irregularities between different geographical electricity markets.

    This thesis investigates in whether it is possible to leverage these volatilities and irregularities between different electricity price markets, to offload or move storage in order to reduce electricity price costs for data storage.

    By forecasting four different electricity price markets it was possible to predict sudden price spikes and leverage these forecasts in a simple optimization model to offload storage of data in data centers and successfully reduce electricity costs for data storage.

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    Data Storage Cost Optimization Based on Electricity Price Forecasting with Machine Learning in a Multi-Geographical Cloud Environment
  • 1062.
    Won Bae, Sang
    et al.
    Kyonggi University, South Korea.
    Korman, Matias
    Tohoku University, Japan.
    Mitchell, Joseph S. B.
    SUNY Stony Brook, NY USA.
    Okamoto, Yoshio
    University of Electrocommun, Japan.
    Polishchuk, Valentin
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering.
    Wang, Haitao
    Utah State University, UT 84322 USA.
    Computing the L-1 Geodesic Diameter and Center of a Polygonal Domain2017In: Discrete & Computational Geometry, ISSN 0179-5376, E-ISSN 1432-0444, Vol. 57, no 3, p. 674-701Article in journal (Refereed)
    Abstract [en]

    For a polygonal domain with h holes and a total of n vertices, we present algorithms that compute the geodesic diameter in time and the geodesic center in time, respectively, where denotes the inverse Ackermann function. No algorithms were known for these problems before. For the Euclidean counterpart, the best algorithms compute the geodesic diameter in or time, and compute the geodesic center in time. Therefore, our algorithms are significantly faster than the algorithms for the Euclidean problems. Our algorithms are based on several interesting observations on shortest paths in polygonal domains.

  • 1063.
    Xiong, Zhitao
    et al.
    The University of New South Wales.
    Olstam, Johan
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Orchestration of driving simulator scenarios based on dynamic actor preparation and automated action planning2015In: Transportation Research Part C: Emerging Technologies, ISSN 0968-090X, E-ISSN 1879-2359, Vol. 56, p. 120-131Article in journal (Refereed)
    Abstract [en]

    In driving simulation, a scenario includes definitions of the road environment, the traffic situation, simulated vehicles’ interactions with the participant’s vehicle and measurements that need to be collected. The scenarios need to be designed in such a way that the research questions to be studied can be answered, which commonly imply exposing the participant for a couple of predefined specific situations that has to be both realistic and repeatable. This article presents an integrated algorithm based on Dynamic Actor Preparation and Automated Action Planning to control autonomous simulated vehicles in the simulation in order to generate predefined situations. This algorithm is thus able to plan driving actions for autonomous vehicles based on specific tasks with relevant contextual information as well as handling longitudinal transportation of simulated vehicles based on the contextual information in an automated manner. The conducted experiment shows that the algorithm is able to guarantee repeatability under autonomous traffic flow. The presented algorithm can benefit not only the driving simulation community, but also relevant areas, such as autonomous vehicle and in-vehicle device design by providing them with an algorithm for target pursue and driving task accomplishment, which can be used to design a human-vehicle cooperation system in the coming era of autonomous driving.

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    fulltext
  • 1064.
    You, Lei
    et al.
    Qingdao University, Peoples R China.
    Lei, Lei
    Linköping University, Department of Science and Technology. Linköping University, Faculty of Science & Engineering.
    Yuan, Di
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering. University of Maryland, MD USA.
    A Performance Study of Energy Minimization for Interleaved and Localized FDMA2014In: 2014 IEEE 19TH INTERNATIONAL WORKSHOP ON COMPUTER AIDED MODELING AND DESIGN OF COMMUNICATION LINKS AND NETWORKS (CAMAD), IEEE , 2014, p. 16-20Conference paper (Refereed)
    Abstract [en]

    Optimal channel allocation is a key performance engineering aspect in single-carrier frequency-division multiple access (SC-FDMA). It is of significance to consider minimum sum power (Min-Power), subject to meeting specified users demand, since mobile users typically employ battery-powered handsets. In this paper, we prove that Min-Power is polynomial-time solvable for interleaved SC-FDMA (IFDMA). Then we propose a channel allocation algorithm for IFDMA, which is guaranteed to achieve global optimum in polynomial time. We numerically compare the proposed algorithm with optimal localized SC-FDMA (LFDMA) for Min-Power. The results show that LFDMA outperforms IFDMA in the maximal supported user demand. When the user demand can be satisfied in both LFDMA and IFDMA, LFDMA performs slightly better than IFDMA. However MinPower is polynomial-time solvable for IFDMA whereas it is not for LFDMA.

  • 1065.
    You, Lei
    et al.
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering.
    Lei, Lei
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering.
    Yuan, Di
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering. University of Maryland, MD 20740 USA.
    Load Balancing via Joint Transmission in Heterogeneous LTE: Modeling and Computation2015In: 2015 IEEE 26TH ANNUAL INTERNATIONAL SYMPOSIUM ON PERSONAL, INDOOR, AND MOBILE RADIO COMMUNICATIONS (PIMRC), IEEE , 2015, p. 1173-1177Conference paper (Refereed)
    Abstract [en]

    As one of the Coordinated Multipoint (CoMP) techniques, Joint Transmission (JT) can improve the overall system performance. In this paper, from the load balancing perspective, we study how the maximum load can be reduced by optimizing JT pattern that characterizes the association between cells and User Equipments (UEs). To give a model of the interference caused by cells with different time-frequency resource usage, we extend a load coupling model, by taking into account JT. In this model, the mutual interference depends on the load of cells coupled in a non-linear system with each other. Under this model, we study a two-cell case and proved that the optimality is achieved in linear time in the number of UEs. After showing the complexity of load balancing in the general network scenario, an iterative algorithm for minimizing the maximum load, named JT-MinMax, is proposed. We evaluate JT-MinMax in a heterogeneous Network (HetNet), though it is not limited to this type of scenarios. Numerical results demonstrate the significant performance improvement of JT-MinMax on min-max cell load, compared to the conventional non-JT solution where each UE is served by the cell with best received transmit signal.

  • 1066.
    You, Lei
    et al.
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering.
    Lei, Lei
    Linköping University, Department of Science and Technology. Linköping University, Faculty of Science & Engineering.
    Yuan, Di
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering. University of Maryland, MD 20740 USA.
    Optimizing Power and User Association for Energy Saving in Load-Coupled Cooperative LTE2016In: 2016 IEEE INTERNATIONAL CONFERENCE ON COMMUNICATIONS (ICC), IEEE , 2016Conference paper (Refereed)
    Abstract [en]

    We consider an energy minimization problem for cooperative LTE networks. To reduce energy consumption, we investigate how to jointly optimize the transmit power and the association between cells and user equipments (UEs), by taking into consideration joint transmission (JT), one of the coordinated multipoint (CoMP) techniques. We formulate the optimization problem mathematically. For solving the problem, a dynamic power allocation algorithm that adjusts the transmit power of all cells, and an algorithm for optimizing the cell-UE association, are proposed. The two algorithms are iteratively used in an algorithmic framework to enhance the energy performance. Numerically, the proposed algorithms can lead to lower energy consumption than the optimal energy setting in the non-JT case. In comparison to fixed power allocation in JT, the proposed dynamic power allocation algorithm is able to significantly reduce the energy consumption.

  • 1067.
    You, Lei
    et al.
    Uppsala Univ, Sweden.
    Liao, Qi
    Nokia Bell Labs, Germany.
    Pappas, Nikolaos
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering.
    Yuan, Di
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering.
    Resource Optimization With Flexible Numerology and Frame Structure for Heterogeneous Services2018In: IEEE Communications Letters, ISSN 1089-7798, E-ISSN 1558-2558, Vol. 22, no 12, p. 2579-2582Article in journal (Refereed)
    Abstract [en]

    We explore the potential of optimizing resource allocation with flexible numerology in frequency domain and variable frame structure in time domain, with services of with different types of requirements. We prove the NP-hardness of the problem and propose a scalable optimization algorithm based on linear programming and Lagrangian duality. Numerical results show significant advantages of adopting flexibility in both time and frequency domains for capacity enhancement and meeting the requirements of mission critical services.

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    fulltext
  • 1068.
    You, Lei
    et al.
    Uppsala University, Sweden.
    Yuan, Di
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering. Uppsala University, Sweden.
    Joint CoMP-Cell Selection and Resource Allocation in Fronthaul-Constrained C-RAN2017In: 2017 15TH INTERNATIONAL SYMPOSIUM ON MODELING AND OPTIMIZATION IN MOBILE, AD HOC, AND WIRELESS NETWORKS (WIOPT), IEEE , 2017Conference paper (Refereed)
    Abstract [en]

    Cloud-based Radio Access Network (C-RAN) is a promising architecture for future cellular networks, in which Baseband Units (BBUs) are placed at a centralized location, with capacity-constrained fronthaul connected to multiple distributed Remote Radio Heads (RRHs) that are far away from the BBUs. The centralization of signal processing enables the flexibility for coordinated multi-point transmission (CoMP) to meet high traffic demand of users. We investigate how to jointly optimize CoMP-cell selection and base station resource allocation so as to enhance the quality of service (QoS), subject to the fronthaul capacity constraint in orthogonal frequency-division multiple access (OFDMA) based C-RAN. The problem is proved to be NP-hard in this paper. To deal with the computational complexity, we derive a partial optimality condition as the foundation for designing a cell-selection algorithm. Besides, we provide a solution method of the optimum of the time-frequency resource allocation problem without loss of fairness on the QoS enhancement of all users. The simulations show good performance of the proposed algorithms for jointly optimizing the cell selection and resource allocation in a C-RAN, with respect to QoS.

  • 1069.
    You, Lei
    et al.
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering.
    Yuan, Di
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering.
    Load Optimization With User Association in Cooperative and Load-Coupled LTE Networks2017In: IEEE Transactions on Wireless Communications, ISSN 1536-1276, E-ISSN 1558-2248, Vol. 16, no 5, p. 3218-3231Article in journal (Refereed)
    Abstract [en]

    We extend the problem of optimizing user association for load balancing in cellular networks along 2-dimensions. First, we consider joint transmission, which is one of the coordinated multipoint techniques with which a user may be simultaneously served by multiple base stations. Second, we account for, mathematically, the coupling relation between the base stations load levels that are dependent on each other due to inter-cell interference. We formulate two optimization problems, sum load minimization (MinSumL) and maximum load minimization (MinMaxL). We prove that both MinSumL and MinMaxL are NP-hard. We propose a mixed integer linear programming based scheme by means of linearization. This approach also leads to a bounding scheme for performance benchmarking. Then, we derive a set of partial optimality conditions. Fulfillment of the conditions will guarantee performance improvement for both MinSumL and MinMaxL. A solution algorithm is then derived based on the conditions. Simulation results are provided to demonstrate the effectiveness of the approaches.

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  • 1070.
    You, Lei
    et al.
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering.
    Yuan, Di
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering. Uppsala University, Sweden.
    Pappas, Nikolaos
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering.
    Värbrand, Peter
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering.
    Energy-Aware Wireless Relay Selection in Load-Coupled OFDMA Cellular Networks2017In: IEEE Communications Letters, ISSN 1089-7798, E-ISSN 1558-2558, Vol. 21, no 1, p. 144-147Article in journal (Refereed)
    Abstract [en]

    We investigate transmission energy minimization via optimizing wireless relay selection in orthogonal-frequency-division multiple access networks. We take into account the impact of the load of cells on transmission energy. We prove the NP-hardness of the energy-aware wireless relay selection problem. To tackle computational complexity, a partial optimality condition is derived for providing insights in respect of designing an effective and efficient algorithm. Numerical results show the resulting algorithm achieves high energy performance.

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  • 1071.
    Yousefi Mojir, Kayvan
    et al.
    Linköping University, Department of Management and Engineering, Information Systems. Linköping University, Faculty of Arts and Sciences.
    Pilemalm, Sofie
    Linköping University, Department of Management and Engineering, Information Systems. Linköping University, Faculty of Arts and Sciences.
    Andersson Granberg, Tobias
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering.
    Semi-professionals: emergency response as an additional task in current occupations2019In: International Journal of Emergency Services, ISSN 2047-0894, E-ISSN 2047-0908, Vol. 8, no 2, p. 86-107Article in journal (Refereed)
    Abstract [en]

    Purpose The purpose of this paper is twofold: first, to identify occupational groups who can act as semi-professional first responders, in order to shorten the response times to frequent emergencies, and second, to identify related opportunities, challenges and needs of training, emergency supplies and information technology (IT) support. Design/methodology/approach A case study approach was taken, combining future workshops, focus groups and an exercise. Network governance was used as an analytical lens. Findings The identified potential groups are security guards, home care personnel, fire services day personnel and facility service personnel. The results show that semi-professionals have a large potential to complement professional resources by carrying out first response or supportive actions vital to the emergency, partly by using already existing cars and equipment. The identified needs include additional basic equipment such as fire extinguishers and first-aid kits, training in basic firefighting, first aid and risk assessment, as well as mobile phone application-based IT support to manage alarms. The major challenges are organisational, economic and juridical, including ambiguities in responsibilities and related insurances. The analysis recognises the new collaboration as a hybrid form of hierarchical government and network governance. Social implications The study suggests that using semi-professional resources can be one of many innovative solutions to recent public sector challenges that have put a huge strain on professional emergency response organisations. Originality/value The study provides a novel view of using semi-professional resources in emergency response, based on the joint perspectives of various occupational groups, and the fire services.

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    Semi-professionals: emergency response as an additional task in current occupations
  • 1072.
    Yousefi Mojir, Kayvan
    et al.
    Linköping University, Department of Management and Engineering, Information Systems. Linköping University, Faculty of Arts and Sciences.
    Pilemalm, Sofie
    Linköping University, Department of Management and Engineering, Information Systems. Linköping University, Faculty of Arts and Sciences.
    Andersson Granberg, Tobias
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering.
    User Participation in Information Systems Development for Emerging Public Sector Initiatives2018Conference paper (Refereed)
    Abstract [en]

    This study is a-posteriori analysis of information systems (IS) development in a cross-sector collaboration case to identify and address user participation challenges in emerging public sector initiatives. The major challenges in the studied case was to develop IS for future cross-sector collaboration in a setting that does not yet exist, i.e. where the tasks, stakeholders and end-users are undefined. To address identified challenges, we suggest a combination of activities based on multiple design groups, scenario-based Future Workshops, focus groups, context-specific frameworks, and practical exercises with after-action-review. We argue that while similar challenges have been discussed in relation to large-scale projects and, sometimes, cross-sector collaboration, IS development for emerging public sector initiatives pose specific issues that need to be addressed.

  • 1073.
    Yuan, Di
    Linköping University, The Institute of Technology. Linköping University, Department of Science and Technology, Communications and Transport Systems.
    A Distributed Hybrid Algorithm for Broadcasting through a Virtual Backbone in Wireless Ad Hoc Networks2006In: Proceedings of IEEE International Symposium on Wireless Pervasive Computing (ISWPC), 2006Conference paper (Refereed)
  • 1074.
    Yuan, Di
    Linköping University, The Institute of Technology. Linköping University, Department of Science and Technology, Communications and Transport Systems.
    An integer programming approach for the minimum-energy broadcast problem in wireless networks2005In: Proceedings of the International Network Optimization Conference INOC,2005, Lisbon, Portugal: University of Lisbon , 2005, p. 643-Conference paper (Refereed)
  • 1075.
    Yuan, Di
    Linköping University, The Institute of Technology. Linköping University, Department of Science and Technology, Communications and Transport Systems.
    Computing optimal or near-optimal trees for minimum energy broadcasting in wireless networks2005In: Proceedings of WiOpt 05: Modeling and Optimization in Mobile, Ad Hoc and Wireless Networks,2005, Los Alamitos, California: IEEE Computer Society , 2005, p. 323-Conference paper (Refereed)
  • 1076.
    Yuan, Di
    Linköping University, The Institute of Technology. Linköping University, Department of Science and Technology, Communications and Transport Systems.
    Distributed Pruning Algorithms Based on Neighborhood Connectivity for Broadcast Communication in Wireless Ad Hoc Networks2005In: IEEE Military Conference,2005, Atlantic City, NJ: IEEE , 2005Conference paper (Refereed)
  • 1077.
    Yuan, Di
    Linköping University, The Institute of Technology. Linköping University, Department of Science and Technology, Communications and Transport Systems.
    Energy-Efficient Broadcasting in Wireless Ad Hoc Networks: Performance Benchmarking and Distributed Algorithms Based on Network Connectivity Characterization2005In: The Eighth ACM/IEEE International Symposium on Modeling, Analysis and Simulation of Wireless and Mobile Systems MSWiM 2005,2005, ACM Press: New York , 2005, p. 28-Conference paper (Refereed)
  • 1078.
    Yuan, Di
    Linköping University, The Institute of Technology. Linköping University, Department of Science and Technology, Communications and Transport Systems.
    OPERATIONS RESEARCH IN MOBILE CELLULAR NETWORK DESIGN2009In: PROCEEDINGS OF THE 10TH INTERNATIONAL SYMPOSIUM ON OPERATIONAL RESEARCH SOR 09, p. 53-54Article in journal (Refereed)
    Abstract [en]

    n/a

  • 1079.
    Yuan, Di
    et al.
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Angelakis, Vangelis
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Chen, Lei
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Karipidis, Eleftherios
    Linköping University, Department of Electrical Engineering, Communication Systems. Linköping University, The Institute of Technology.
    Larsson, Erik G.
    Linköping University, Department of Electrical Engineering, Communication Systems. Linköping University, The Institute of Technology.
    On Optimal Link Activation with Interference Cancelation in Wireless Networking2013In: IEEE Transactions on Vehicular Technology, ISSN 0018-9545, E-ISSN 1939-9359, Vol. 62, no 2, p. 939-945Article in journal (Refereed)
    Abstract [en]

    A fundamental aspect in performance engineering of wireless networks is optimizing the set of links that can be concurrently activated to meet given signal-to-interference-and-noise ratio (SINR) thresholds. The solution of this combinatorial problem is the key element in scheduling and cross-layer resource management. In this paper, we assume multiuser decoding receivers, which can cancel strongly interfering signals. As a result, in contrast to classical spatial reuse, links being close to each other are more likely to be active concurrently. Our focus is to gauge the gain of successive interference cancellation (SIC), as well as the simpler, yet instructive, case of parallel interference cancellation (PIC), in the context of optimal link activation. We show that both problems are NP-hard and develop compact integer linear programming formulations that enable to approach global optimality. We provide an extensive numerical performance evaluation, indicating that for low to medium SINR thresholds the improvement is quite substantial, especially with SIC, whereas for high SINR thresholds the improvement diminishes and both schemes perform equally well.

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  • 1080.
    Yuan, Di
    et al.
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Angelakis, Vangelis
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Lei, Lei
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Minimum-Length Scheduling in Wireless Networks with Multi-User Detection and Interference Cancellation: Optimization and Performance Evaluation2012In: IEEE International Conference on Communication Systems (ICCS), 2012, Piscataway, NJ, USA: IEEE , 2012, p. 315-319Conference paper (Refereed)
    Abstract [en]

    Minimum-length scheduling has been a subject of extensive research in performance engineering of wireless ad hoc networks. We consider the problem under the unconventional setting of multi-user detection receivers that can perform decoding successively, potentially admitting interference cancellation. Thus, in contrast to classical spatial reuse, strong interference is not necessarily harmful. The paper studies fundamental aspects of assessing the achievable performance by successive decoding and interference cancellation versus that of the conventional setup. Computationally, the task is very challenging - the optimal decoding pattern is intertwined with the composition of time slots. We provide structural results of the problem, and develop integer programming formulations enabling to effectively determine the optimal schedule. Computational experiments are provided to shed light on the achievable performance gain of successive decoding with interference cancellation for minimum-length scheduling.

  • 1081.
    Yuan, Di
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Science and Technology, Communications and Transport Systems.
    Bauer, Joanna
    University of Bergen, Bergen, Norway.
    Haugland, Dag
    University of Bergen, Bergen, Norway.
    Minimum-Energy Broadcast and Multicast in Wireless Networks: An Integer Programming Approach and Improved Heuristic Algorithms2008In: Ad hoc networks, ISSN 1570-8705, E-ISSN 1570-8713, Vol. 6, no 5, p. 696-717Article in journal (Refereed)
    Abstract [en]

    Both integer programming models and heuristic algorithms have been proposed for finding minimum-energy broadcast and multicast trees in wireless ad hoc networks. Among heuristic algorithms, the broadcast/multicast incremental power (BIP/MIP) algorithm is most known. The theoretical performance of BIP/MIP has been quantified in several studies. To assess the empirical performance of BIP/MIP and other heuristic algorithms, it is necessary to compute an optimal tree or a very good lower bound of the optimum. In this paper, we present an integer programming approach as well as improved heuristic algorithms. Our integer programming approach comprises a novel integer model and a relaxation scheme. Unlike previously proposed models, the continuous relaxation of our model leads to a very sharp lower bound of the optimum. Our relaxation scheme allows for performance evaluation of heuristics without having to compute optimal trees. Our contributions to heuristic algorithms consist of the power-improving algorithm successive power adjustment (SPA), and improved time complexity of some previously suggested algorithms. We report extensive numerical experiments. Algorithm SPA finds better solutions in comparison to a host of other algorithms. Moreover, the integer programming approach shows that trees found by algorithm SPA are optimal or near-optimal.

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  • 1082.
    Yuan, Di
    et al.
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Haugland, Dag
    University of Bergen, Norway .
    Dual Decomposition for Computational Optimization of Minimum-Power Shared Broadcast Tree in Wireless Networks2012In: IEEE Transactions on Mobile Computing, ISSN 1536-1233, E-ISSN 1558-0660, Vol. 11, no 12, p. 2008-2019Article in journal (Refereed)
    Abstract [en]

    We consider the problem of constructing a shared broadcast tree (SBT) in wireless networks, such that the total power required for supporting broadcast initiated by all source nodes is minimal. In the well-studied minimum-energy broadcast (MEB) problem, the optimal tree varies by source. In contrast, SBT is source-independent, thus substantially reducing the overhead for information storage and processing. The SBT problem also differs from the range assignment problem (RAP), because the power for message forwarding in SBT, although being source-independent, depends on from which tree neighbor the message is received. We approach SBT from a computational optimization standpoint, and present a dual decomposition method applied to an optimization model that embeds multiple directed trees into a shared tree. For the dual decomposition method, some of the constraints in the model are preferably formulated implicitly. The dual decomposition scheme is coupled with a fast local search algorithm. We report computational results demonstrating the effectiveness of the proposed approach. In average, the performance gap to global optimality is less than three percent.

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  • 1083.
    Yuan, Di
    et al.
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Joung, Jingon
    ASTAR, Singapore .
    Keong Ho, Chin
    ASTAR, Singapore .
    Sun, Sumei
    ASTAR, Singapore .
    On Tractability Aspects of Optimal Resource Allocation in OFDMA Systems2013In: IEEE Transactions on Vehicular Technology, ISSN 0018-9545, E-ISSN 1939-9359, Vol. 62, no 2, p. 863-873Article in journal (Refereed)
    Abstract [en]

    Joint channel and rate allocation with power minimization in orthogonal frequency-division multiple access (OFDMA) has attracted extensive attention. Most of the research has dealt with the development of suboptimal but low-complexity algorithms. In this paper, the contributions comprise new insights from revisiting tractability aspects of computing the optimum solution. Previous complexity analyses have been limited by assumptions of fixed power on each subcarrier or power-rate functions that locally grow arbitrarily fast. The analysis under the former assumption does not generalize to problem tractability with variable power, whereas the latter assumption prohibits the result from being applicable to well-behaved power-rate functions. As the first contribution, we overcome the previous limitations by rigorously proving the problem's NP-hardness for the representative logarithmic rate function. Next, we extend the proof to reach a much stronger result, namely, that the problem remains NP-hard, even if the channels allocated to each user are restricted to be a consecutive block with given size. We also prove that, under these restrictions, there is a special case with polynomial-time tractability. Then, we treat the problem class where the channels can be partitioned into an arbitrarily large but constant number of groups, each having uniform gain for every individual user. For this problem class, we present a polynomial-time algorithm and provide its optimality guarantee. In addition, we prove that the recognition of this class is polynomial-time solvable.

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  • 1084.
    Yuan, Di
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Science and Technology, Communications and Transport Systems.
    Siomina, Iana
    Linköping University, The Institute of Technology. Linköping University, Department of Science and Technology.
    Pilot power optimization in WCDMA networks2004In: 2nd Workshop on Modeling and Optimization in Mobile, Ad Hoc and Wireless Networks,2004, Cambridge, UK: Cambridge University Press , 2004, p. 191-Conference paper (Refereed)
  • 1085.
    Yuan, Di
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Science and Technology, Communications and Transport Systems.
    Värbrand, Peter
    Linköping University, The Institute of Technology. Linköping University, Department of Science and Technology.
    Resource allocation of spatial time division multiple access in multi-hop radio networks2005In: Resource Management in Wireless Networking / [ed] Mihaela Cardei, Ionut Cardei, Ding-Zhu Du, New York: Springer , 2005, 1, p. -695Chapter in book (Other academic)
    Abstract [en]

    This is the first book that provides readers with a deep technical overview of recent advances in resource management for wireless networks at different layers of the protocol stack. The subject is explored in various wireless networks, such as ad-hoc wireless networks, 3G/4G cellular, IEEE 802.11, and Bluetooth personal area networks.

    Survey chapters give an excellent introduction to key topics in resource management for wireless networks, while experts will be satisfied by the technical depth of the knowledge imparted in chapters exploring hot research topics.

    The subject area discussed in this book is very relevant today, considering the recent remarkable growth of wireless networking and the convergence of wireless personal communications, Internet technologies and real-time multimedia.

    This volume is a very good companion for practitioners working on implementing solutions for multimedia and Quality of Service – sensitive applications over wireless networks.

  • 1086.
    Yung, Tamara
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Traffic Modelling Using Parabolic Differential Equations2013Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The need of a working infrastructure in a city also requires an understanding of how the traffic flows. It is known that increasing number of drivers prolong the travel time and has an environmental effect in larger cities. It also makes it more difficult for commuters and delivery firms to estimate their travel time. To estimate the traffic flow the traffic department can arrange cameras along popular roads and redirect the traffic, but this is a costly method and difficult to implement. Another approach is to apply theories from physics wave theory and mathematics to model the traffic flow; in this way it is less costly and possible to predict the traffic flow as well. This report studies the application of wave theory and expresses the traffic flow as a modified linear differential equation. First is an analytical solution derived to find a feasible solution. Then a numerical approach is done with Taylor expansions and Crank-Nicolson’s method. All is performed in Matlab and compared against measured values of speed and flow retrieved from Swedish traffic department over a 24 hours traffic day. The analysis is performed on a highway stretch outside Stockholm with no entries, exits or curves. By dividing the interval of the highway into shorter equal distances the modified linear traffic model is expressed in a system of equations. The comparison between actual values and calculated values of the traffic density is done with a nominal average difference. The results reveal that the numbers of intervals don’t improve the average difference. As for the small constant that is applied to make the linear model stable is higher than initially considered.

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  • 1087.
    Zhang, Xingjun
    et al.
    Xi An Jiao Tong University, Peoples R China .
    Jing, Cuiping
    Xi An Jiao Tong University, Peoples R China .
    Tang, Feilong
    Shanghai Jiao Tong University, Peoples R China .
    Fowler, Scott
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Cui, Huali
    Xi An Jiao Tong University, Peoples R China .
    Dong, Xiaoshe
    Xi An Jiao Tong University, Peoples R China .
    Joint redundant and random network coding for robust video transmission over lossy networks2012In: International Journal of Mobile Information Systems, ISSN 1574-017X, E-ISSN 1875-905X, Vol. 8, no 3, p. 213-230Article in journal (Refereed)
    Abstract [en]

    In this paper a novel unequal packet loss protection scheme R2NC based on low-triangular global coding matrix with ladder-shaped partition is presented, which combines redundant and random network coding for robust H.264/SVC video transmission. Firstly, the error-correcting capabilities of redundant network coding make our scheme resilient to loss. Secondly, the implementation of random network coding at the intermediate nodes with multiple input links can reduce the cost of network bandwidth, thus reducing the end-to-end delay for video transmission. Thirdly, the low-triangular global coding matrix with ladder-shaped partition is maintained throughout the R2NC processes to reduce the impact of global coding matrixs rank deficiency on video transmission and provide unequal erasure protection for H.264/SVC priority layers. The redundant network coding avoids the retransmission of lost packets and improves error-correcting capabilities of lost packets. Based only on the knowledge of the packet loss rates on the output links, the source node and intermediate nodes can make decisions for redundant network coding and random network coding (i.e., how much redundancy to add at this node). However, the redundancy caused by redundant network coding makes the network load increases. In order to improve network throughput, we performed random network coding at the intermediate nodes. Our approach is grounded on the overall distortion of reconstructed video minimization by optimizing the amount of redundancy assigned to each layer. The convex optimization model is constructed under the constraint of network coding and scalable video coding. Experimental results are shown to demonstrate the significant improvement of H.264/SVC video reconstruction quality with R2NC over packet lossy networks.

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  • 1088.
    Zhang, Xingjun
    et al.
    Xi’an Jiaotong University, Department of Computer Science, China.
    Peng, Xiaohong
    School of Engineering and Applied Science, Aston University, UK.
    Fowler, Scott
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Wu, Dajun
    Institute for Infocomm Research, Singapore.
    Robust H.264/AVC Video Transmission using Data Partitioning and Unequal Loss Protection2010In: IEEE 10th International Conference on Computer and Information Technology (CIT), 2010 / [ed] IEEE, Piscataway, NJ, USA: IEEE , 2010, p. 2471-2477Conference paper (Refereed)
    Abstract [en]

    In this work, we present an adaptive unequal loss protection (ULP) scheme for H264/AVC video transmission overlossy networks. This scheme combines erasure coding, H.264/AVC error resilience techniques and importance measures in videocoding. The unequal importance of the video packets is identifiedin the group of pictures (GOP) and the H.264/AVC data partitioning levels. The presented method can adaptively assign unequal amount of forward error correction (FEC) parity acrossthe video packets according to the network conditions, such as the available network bandwidth, packet loss rate and average packet burst loss length. A near optimal algorithm is developed to dealwith the FEC assignment for optimization. The simulation resultsshow that our scheme can effectively utilize network resources such as bandwidth, while improving the quality of the video transmission. In addition, the proposed ULP strategy ensures graceful degradation of the received video quality as the packet loss rate increases.

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  • 1089.
    Zhang, Xingjun
    et al.
    Xi An Jiao Tong University, Peoples R China .
    Wu, Yuxing
    Xi An Jiao Tong University, Peoples R China .
    Fowler, Scott
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Cen, Song
    Xi An Jiao Tong University, Peoples R China .
    Dong, Xiaoshe
    Xi An Jiao Tong University, Peoples R China .
    Joint Source-Channel Coding With Unequal Protection For Real-Time Scalable Video Transmission2014In: Intelligent Automation and Soft Computing, ISSN 1079-8587, E-ISSN 2326-005X, Vol. 20, no 1, p. 77-90Article in journal (Refereed)
    Abstract [en]

    In real-time video transmission, the distortion of video content may be caused by video compression in source coding and packets loss in transmission. Meanwhile the source coding distortion and transmission distortion are often mutually affected. There is a fundamental tradeoff between them for achieving the best video transmission quality. In order to make wise use of network resources, this paper proposes a video transmission scheme in which the source coding distortion and transmission distortion to the video quality are formulated and fountain code is used as the channel coding for unequal protection in scalable video transmission. The network packet loss and the characteristic of scalable video are quantitated in our proposed rate distortion model, which formulates the real-time video transmission system in a bandwidth limited network. We introduce a computerized algorithm. The computerized algorithm will determine the optimal source rate of the video coding and the optimal redundancy amount assigned to each scalable video layer. Our proposed algorithm can guarantee that the optimal quality of real-time video transmission will be achieved and the total real-time video transmission distortion will be reduced dramatically.

  • 1090.
    Zhang, Xingjun
    et al.
    Xi’an Jiaotong University, Xi’an, China.
    Zhang, Xuan
    Xi’an Jiaotong University, Xi’an, China.
    Fu, Zhe
    Xi’an Jiaotong University, Xi’an, China.
    Yu, Bocheng
    Xi’an Jiaotong University, Xi’an, China.
    Fowler, Scott
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering.
    Joint Distortion Estimation and Layer Selection of Unequal Error Protection for SVC Video Transmission over FSO Networks2019In: 2019 IEEE 21st International Conference on High Performance Computing and Communications; IEEE 17th International Conference on Smart City; IEEE 5th International Conference on Data Science and Systems (HPCC/SmartCity/DSS), Piscataway, New Jersey, US, 2019, p. 726-733Conference paper (Refereed)
    Abstract [en]

    To meet the needs of high throughput, low delay and high resolution video services, the free space optical network (FSO) has recently received increasing attention due to its large bandwidth and high transmission rate. However, atmospheric turbulence is a major challenge, which can lead to severe BER performance degradation or even make the link ineffective. To mitigate the significant degradation of the video streaming quality on FSO networks, in this paper, an unequal error protection (UEP) scheme for scalable video coding is designed to minimize the video distortion. By adaptively choosing the number of video layers and the redundancy rate of the channel coding, unequal error protection of Scalable video coding is achieved. In addition, to solve the optimization model, a heuristic-based fast algorithm is proposed. A large number of simulation experiments in an NS3 network simulator show that the proposed scheme offers significantly higher quality in the reconstructed video sequences.

  • 1091.
    Zhang, Xingjun
    et al.
    Xi An Jiao Tong University, Peoples R China.
    Zhu, Guofeng
    Xi An Jiao Tong University, Peoples R China.
    Wang, Endong
    Inspur Beijing Elect Informat Ind Co Ltd, Peoples R China.
    Fowler, Scott
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering.
    Dong, Xiaoshe
    Xi An Jiao Tong University, Peoples R China.
    Data De-Duplication with Adaptive Chunking and Accelerated Modification Identifying2016In: Computing and informatics, ISSN 1335-9150, Vol. 35, no 3, p. 586-614Article in journal (Refereed)
    Abstract [en]

    The data de-duplication system not only pursues the high de-duplication rate, which refers to the aggregate reduction in storage requirements gained from de-duplication, but also the de-duplication speed. To solve the problem of random parameter-setting brought by Content Defined Chunking (CDC), a self-adaptive data chunking algorithm is proposed. The algorithm improves the de-duplication rate by conducting pre-processing de-duplication to the samples of the classified files and then selecting the appropriate algorithm parameters. Meanwhile, FastCDC, a kind of content-based fast data chunking algorithm, is adopted to solve the problem of low de-duplication speed of CDC. By introducing de-duplication factor and acceleration factor, FastCDC can significantly boost de-duplication speed while not sacrificing the de -duplication rate through adjusting these two parameters. The experimental results demonstrate that our proposed method can improve the de -duplication rate by about 5 %, while FastCDC can obtain the increase of de -duplication speed by 50 % to 200 % only at the expense of less than 3 % de duplication rate loss.

  • 1092.
    Zhao, Chao
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Angelakis, Vangelis
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Yuan, Di
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Timus, Bogdan
    Ericsson Research, Kista, Sweden.
    Evaluation of Cell Selection Algorithms in LTE-Advanced Relay Networks2013Conference paper (Refereed)
    Abstract [en]

    The concept of relay has been introduced in LTE-Advanced as a promising approach to enhance network performance. Because of the diversity introduced by deploying relays to a purely macro network, the conventional cell selection schemes do not perform well, leading to noticeable throughput degradation for some of the users. An algorithm attempting to address the issue is the use of data rate mapped from Reference Signal Received Power (RSRP) as the cell selection criterion. This algorithm, however, introduces an extra interference problem. We therefore describe an additional interference avoidance (IA) mechanism to enhance it. Performance evaluation and analysis are carried out to gain insights on the enhanced algorithm and two additional algorithms, both developed in this paper, to demonstrate their effectiveness in improving the throughput. Simulation results show that for relay-enabled networks the new algorithms based on data rates obtained directly from RSRP and the Reference Signal Received Quality (RSRQ) outperform the algorithm based on RSRP with offset. Moreover, the interference issue is well dealt with via the implementation of additional IA.

  • 1093.
    Zhao, Hongmei
    et al.
    Linköping University, Department of Mathematics, Optimization . Linköping University, The Institute of Technology.
    Lei, Lei
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Yuan, Di
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Larsson, Torbjörn
    Linköping University, Department of Mathematics, Optimization . Linköping University, The Institute of Technology.
    Rönnberg, Elina
    Linköping University, Department of Mathematics, Optimization . Linköping University, The Institute of Technology.
    Power efficient uplink scheduling in SC-FDMA: Bounding global optimality by column generation2013In: 2013 IEEE 18th International Workshop on Computer Aided Modeling and Design of Communication Links and Networks (CAMAD, IEEE , 2013, p. 119-123Conference paper (Refereed)
    Abstract [en]

    We study resource allocation in cellular systems and consider the problem of finding a power efficient scheduling in an uplink single carrier frequency division multiple access (SC-FDMA) system with localized allocation of subcarriers, that is, the subcarriers allocated to a user equipment have to be consecutive in the frequency domain in each time slot. This problem is discrete and nonconvex, thus the use of suboptimal algorithms has been a common practice. We leverage the power of mathematical programming in order to approach global optimality or a tight bounding interval confining global optimum, to arrive at an effective scheme for gauging the performance of suboptimal algorithms. Toward this end, we first provide a straightforward integer linear programming formulation, and then an alternative and less trivial, so-called column-oriented, formulation. The latter is solved by column generation, which is a solution technique for large-scale optimization problems with certain characteristics. The computational evaluation demonstrates that the column generation method produces very highquality subcarrier allocations that either coincide with the global optimum or enable an extremely sharp bounding interval. Hence the approach serves well for the purpose of benchmarking results for large-scale instances of power efficient SC-FDMA scheduling.

  • 1094.
    Zhao, Yixin
    et al.
    Nanjing Univ Sci and Technol, Peoples R China.
    Larsson, Torbjörn
    Linköping University, Department of Mathematics, Optimization . Linköping University, Faculty of Science & Engineering.
    Yuan, Di
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering.
    Rönnberg, Elina
    Linköping University, Department of Mathematics, Optimization . Linköping University, Faculty of Science & Engineering.
    Lei, Lei
    Linköping University, Department of Science and Technology. Linköping University, Faculty of Science & Engineering.
    Correction: Power efficient uplink scheduling in SC-FDMA: benchmarking by column generation (vol 17, pg 695, 2016)2019In: Optimization and Engineering, ISSN 1389-4420, E-ISSN 1573-2924, Vol. 20, no 3, p. 959-959Article in journal (Other academic)
    Abstract [en]

    At the time of the final publication of the paper, in December 2016, Yixin Zhaos affiliation had changed.

  • 1095.
    Zhao, Yixin
    et al.
    Linköping University, Department of Mathematics, Optimization . Linköping University, Faculty of Science & Engineering.
    Larsson, Torbjörn
    Linköping University, Department of Mathematics, Optimization . Linköping University, Faculty of Science & Engineering.
    Yuan, Di
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering.
    Rönnberg, Elina
    Linköping University, Department of Mathematics, Optimization . Linköping University, Faculty of Science & Engineering.
    Lei, Lei
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering.
    Power efficient uplink scheduling in SC-FDMA: benchmarking by column generation2016In: Optimization and Engineering, ISSN 1389-4420, E-ISSN 1573-2924, Vol. 17, no 4, p. 695-725Article in journal (Refereed)
    Abstract [en]

    We study resource allocation in cellular systems and consider the problem of finding a power efficient scheduling in an uplink single carrier frequency division multiple access system. Due to the discrete nature of this problem and its computational difficulty, particularly in a real-time setting, the use of suboptimal algorithms is common practice. We aim at an effective way of gauging the performance of suboptimal algorithms by finding tight bounds on the global optimum. Toward this end, we first provide a basic integer linear programming formulation. Then we propose a significantly stronger column-oriented formulation and a corresponding column generation method, as well as an enhanced column generation scheme. The latter extends the first scheme through the inclusion of a stabilization technique, an approximate column generation principle, and a tailored heuristic that is embedded in the column generation scheme to find high-quality though not necessarily global optimal solutions. The computational evaluation demonstrates that compared with a poor performance by the integer linear programming formulation, the column generation method can produce near-optimal schedules that enable a sharp bounding interval. The enhanced column generation method significantly sharpens the bounding interval. Hence the column generation approach serves well for the purpose of benchmarking results for large-scale instances.

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    fulltext
  • 1096.
    Ziedén, Therése
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Development of a Logit model of the transition effect to public transport2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The importance of traffic planning has, throughout the years, been in- creased, providing sustainable developments of traffic and infrastructural investments. The analysis of the current traffic situation and the evalua- tion of the effects of a future investment are crucial for the socio-economic benefits maintenance. These analyses and evaluations are most commonly done using traffic simulation models. One of the main traffic planning aims, nowadays, is to increase the number of public transport users against the number of private car users. This change in mode choice is called transition effect and could be beneficial both from an environmental and socio-economic perspective. This thesis aims to evaluate and improve the macroscopic traffic demand and transition model, used fot the city of Norrköping. Additionally, the thesis investigates if a general transition Logit model can be developed and which parameters are the most important to be included in a modal choice estimation. For the needs of this study, the traffic planning software Visum is used. The travel mode distribution is calculated by Logit models coded in Python-scripts integrated in Visum. Then, a traffic assignment is performed by Visum, computing new travel times as inputs to the Logit model and this iterative procedure continues until the system reaches an equilibrium. The thesis aims for a more reliable prediction of the transition effect by correcting the Python-scripts and estimating the parameters of the Logit model using data from surveys. The study shows that travel times is the most important factor for realistic results generation. However, the data used for the estimation of the Logit model parameters did not include sufficient information of travel times. The travel times had to be calculated, using two different methods, in order to be included in the estimation of new parameters. Although these methods could not provide any positive effects on the transition, they did prove the importance and significance travel time have when developing a traffic model. The result of the study invokes the importance to further develop the method of calculating travel times, when the input data is not sufficient, and shows that the travel time parameters are case specific.

    Download full text (pdf)
    Development of a Logit model of the transition effect to public transport
  • 1097.
    Zohrevandi, Elmira
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Effects of Complexity Factors on Controllers Workload in Stockholm Terminal Area2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Through a history of more than 50 years, the results of mathematical models have shown that controller workload is being driven by the complexity involved in the airspace environment. Part of this complexity is prompted by the dynamical behavior of traffic patterns. From the results of models describing controller’s workload, it is observed that predictability decreases the complexity. Therefore, the general idea behind this topic is to analyze how a specific notion of predictability influences the controller’s workload. This specific notion in this research is a type of automation that aircraft benefit from. In a more specific sense, the goal of this research was to analyze how the controllers handle the air traffic in different complex situations when exposed to different automation levels. The following dilemmas are focused through this work: - Information visualization of controllers’ interaction with radar screen - Quantification of dynamics of air traffic patterns - Modeling and quantification of controllers’ workload First, in order to have a grasp of the controllers’ interaction with the air traffic patterns, the controllers’ activities on the radar screen have been visualized in chapter 2. The visualization results for different automated conditions have been analyzed. Based on such analysis the criteria for problem space has been addressed and the main research question is identified. Next in chapter 3, the airspace complexity caused by air traffic flow has been studied and a set of known complexity factors are quantified using a novel calculation approach. With a logistics perspective toward airspace complexity, to calculate each complexity factor, a mathematical formulation has been used and the effects of each corresponding factor on controllers’ workload are addressed. Then in chapter 4, a novel approach toward modeling controller’s workload is presented. After implementing the model on 18 different scenarios, a model for controller’s workload has been developed in which around 60 percent of the en-route air traffic complexity values and around 80 percent of terminal air traffic complexity values could be well-matched with the workload values. From statistical point of view, the results are very much acceptable for experiments in which human factors are involved. Cognitive load has not been considered in the workload model which is the focus of a future work. Later on in chapter 5, the results for each complexity factor as well as workload models are analyzed and discussed for each sector separately. Based on the airspace complexity results, areas where traffic situation had become complex were identified and the controller’s response to different situations are discussed. For each complexity factor as well as workload, the results for three different scenarios featuring different automation levels for two en-route and terminal sectors are compared. At last in chapter 6, the main ideas are discussed, thesis conclusions are presented and possible future work is suggested.

    Download full text (pdf)
    Effects of Complexity Factors on Controllers Workload in Stockholm Terminal Area
  • 1098.
    Åsa, Weinholt
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Exploring Collaboration Between the Fire and Rescue Service and New Actors: Cost-efficiency and Adaptation2015Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    The emergency services serves an important purpose in society by ensuring that people in need, regardless of their geographical location, receives help when they fall victims to undesirable incidents. Existing resources are however often limited and concentrated to urban areas making travel distances to remote areas long. Local authorities are also facing budget constraints and clients are becoming more demanding. This means that the emergency services need to do more, but with less resources. Collaboration with new actors has therefore been proposed as a solution. There exist several actors with basic knowledge in both fire suppression or medical treatment that might be able to contribute at an early stage in order to reduce response time and provide help to citizens in need. However, little research has been dedicated to investigating the possibilities and the potential of new collaborative practices in every day accidents.

    In this thesis collaboration between new actors and the fire and rescue service (FRS) in Sweden is studied. The aim is to analyze whether collaborative practices leads to an increased cost-efficiency, for the FRS and society as a whole. The thesis also aims to analyze how traditional actors and new actors adapt to collaborative practices.

    For evaluating cost-efficiency in the FRS stochastic frontier analysis is used and for analyzing the societal effects cost-benefit analysis is applied. In total three cases are studied; (1) security officers assisting the FRS in fire alarms (2) home care nurses collaborating with the FRS in medical alarms and (3) citizens responding to FRS-alarms through SMS.

    The results do not show that collaboration have led to increased cost-efficiency in the FRS during the studied time period. However, despite that no evidence for increased cost-efficiency is found in the FRS, there are several societal gains from collaborating related to e.g. equity, quality and effectiveness. And the costs for implementing collaborative arrangements are relatively low. It is however argued that to be able to get the most out of collaboration more emphasis should be put on building common platforms, where the different organizations and actors can communicate, share experiences, organize joint training sessions and actually collaborate. Today interaction outside the rescue site hardly exist between the collaborative partners; the actual collaboration between the FRS and the new actors is limited only to the response phase. Also, the FRS do not adapt their bureaucratic structures to collaborate with the new actors. Instead the changes associated with collaboration affect mainly the new actors, as an addition to their regular duties. Factors related to discretion, professional identity and personal motivation are identified as important for understanding how new actors adapt to collaboration.

    List of papers
    1. The Influence of Organizational Changes on Cost Efficiency in Fire and Rescue Services
    Open this publication in new window or tab >>The Influence of Organizational Changes on Cost Efficiency in Fire and Rescue Services
    (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    Fire and rescue services in Sweden have recently undergone organizational changes aiming at improving service quality and efficiency. Among those changes are an increased number of formalized cooperations between FRSs in neighboring municipalities, increased collaboration with other sectors in day-to-day operations, changes in the structure of rescue teams, and an increase in the tasks performed by the services. The purpose of this study was to evaluate whether these policy changes have resulted in increased cost efficiency in the Swedish FRS. We used stochastic frontier analysis of annual data from 2009 to 2012 for 205 Swedish municipalities, taking into account the relevant differences in conditions among them. The conclusion is that there is no evidence to be found of improved efficiency in the FRS. The policy changes that have been implemented have not had the desired effects, and most of the policy variables tested for inclusion in the model were not found significant. Recommendations for future research are to further investigate why these policy changes have not yet given the expected results, to examine how and if collaboration with different types of organizations (public, private and non-profit) affects efficiency differently and to make further in-depth comparisons between the most efficient and least efficient FRSs for there are great variations between them.

    Keywords
    Fire and rescue services, Stochastic frontier analysis, Efficiency evaluation, Benchmarking
    National Category
    Communication Studies Transport Systems and Logistics
    Identifiers
    urn:nbn:se:liu:diva-115797 (URN)
    Available from: 2015-03-20 Created: 2015-03-20 Last updated: 2015-03-20Bibliographically approved
    2. New collaborations in daily emergency response: Applying cost benefit analysis to new first response initiatives in the Swedish fire and rescue service
    Open this publication in new window or tab >>New collaborations in daily emergency response: Applying cost benefit analysis to new first response initiatives in the Swedish fire and rescue service
    2015 (English)In: International Journal of Emergency Services, ISSN 2047-0894, E-ISSN 2047-0908, Vol. 4, no 2, p. 177-193Article in journal (Refereed) Published
    Abstract [en]

    Purpose

    – The purpose of this paper is to analyse costs and benefits from new collaborations in daily emergency response and to demonstrate how cost-benefit analysis (CBA) can be used for evaluating effects from these kinds of collaborations.

    Design/methodology/approach

    – CBA is used to evaluate two collaborations. The cases are: security officers that respond to fire and rescue service (FRS) calls; and home care nurses that assist the FRSs when they respond to urgent medical calls. Interviews, public documents and incident reports have been used as sources of data.

    Findings

    – Most costs are relatively straightforward to estimate. More difficult to estimate are the turn-out costs, including the services that cannot be performed when the new actors take on new assignments. One important benefit from these kinds of collaborations is reduced response time. Other benefits include increased situational awareness and improved preventive work in Case 1, as well as improved working conditions for the traditional resources and increased medical competence in Case 2. The analysis indicate that the case with the security officers most likely was socially beneficial, while the case with the home care nurses at the time of the study was not.

    Originality/value

    – The authors provide a thorough description and analysis of two interesting new ways of performing daily emergency response. Furthermore, the authors depict how CBA can be used to structure the analysis and evaluation of new initiatives in emergence services and how it can be used for identifying improvement potential. The authors also identify and discuss what is needed in terms of documentation as well as research, for it to be possible to improve the quantitative analysis of these kinds of initiatives

    Place, publisher, year, edition, pages
    Emerald Group Publishing Limited, 2015
    Keywords
    Cost-benefit analysis, emergency services, first responders, fire and rescue services, economic evaluation, cost-efficiency
    National Category
    Communication Studies Transport Systems and Logistics
    Identifiers
    urn:nbn:se:liu:diva-115798 (URN)10.1108/IJES-01-2015-0002 (DOI)
    Funder
    Swedish Civil Contingencies Agency
    Note

    The status of this article was previously Manuscript.

    Available from: 2015-03-20 Created: 2015-03-20 Last updated: 2017-12-04Bibliographically approved
    3. Front-line Staff Collaboration: Adaptation to New Practices within the Fire and Rescue Service
    Open this publication in new window or tab >>Front-line Staff Collaboration: Adaptation to New Practices within the Fire and Rescue Service
    (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    This paper analyses collaborative practice within the fire and rescue services (FRS), with the aim to describe how the FRS adapt to a collaborative service delivery and to provide a theoretical understanding of the new type of actors emerging in such context. The findings are based on three collaborative cases. The data consist of public documents, interviews, and incident reports. The findings show that FRS does not adapt to a collaborative setting, instead the adjustment is made by the new actors. Discretion, professional identity, and personal motivation are factors related to understanding the new front-line actors that emerge within this context.

    Keywords
    Front-line staff, collaboration, local government, fire and rescue services
    National Category
    Communication Studies Transport Systems and Logistics
    Identifiers
    urn:nbn:se:liu:diva-115799 (URN)
    Available from: 2015-03-20 Created: 2015-03-20 Last updated: 2015-03-20Bibliographically approved
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  • 1099.
    Åström, Freddie
    et al.
    Linköping University, Department of Electrical Engineering, Computer Vision. Linköping University, The Institute of Technology. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Baravdish, George
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Felsberg, Michael
    Linköping University, Department of Electrical Engineering, Computer Vision. Linköping University, The Institute of Technology. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    A Tensor Variational Formulation of Gradient Energy Total Variation2015In: ENERGY MINIMIZATION METHODS IN COMPUTER VISION AND PATTERN RECOGNITION, EMMCVPR 2015, Springer Berlin/Heidelberg, 2015, Vol. 8932, p. 307-320Conference paper (Refereed)
    Abstract [en]

    We present a novel variational approach to a tensor-based total variation formulation which is called gradient energy total variation, GETV. We introduce the gradient energy tensor into the GETV and show that the corresponding Euler-Lagrange (E-L) equation is a tensor-based partial differential equation of total variation type. Furthermore, we give a proof which shows that GETV is a convex functional. This approach, in contrast to the commonly used structure tensor, enables a formal derivation of the corresponding E-L equation. Experimental results suggest that GETV compares favourably to other state of the art variational denoising methods such as extended anisotropic diffusion (EAD) and total variation (TV) for gray-scale and colour images.

    Download full text (pdf)
    fulltext
  • 1100.
    Åström, Freddie
    et al.
    Linköping University, Department of Electrical Engineering, Computer Vision. Linköping University, The Institute of Technology.
    Baravdish, George
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, The Institute of Technology.
    Felsberg, Michael
    Linköping University, Department of Electrical Engineering, Computer Vision. Linköping University, The Institute of Technology.
    On Tensor-Based PDEs and their Corresponding Variational Formulations with Application to Color Image Denoising2012Conference paper (Refereed)
    Abstract [en]

    The case when a partial differential equation (PDE) can be considered as an Euler-Lagrange (E-L) equation of an energy functional, consisting of a data term and a smoothness term is investigated. We show the necessary conditions for a PDE to be the E-L equation for a corresponding functional. This energy functional is applied to a color image denoising problem and it is shown that the method compares favorably to current state-of-the-art color image denoising techniques.

    Download full text (pdf)
    On Tensor-Based PDEs and their Corresponding Variational Formulations with Application to Color Image Denoising
    Download (zip)
    Program_code_ECCV2012
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