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  • 1.
    Adenskog, Magnus
    et al.
    Örebro University, School of Humanities, Education and Social Sciences. Urban Studies.
    Åström, Joachim
    Örebro University, School of Humanities, Education and Social Sciences. Urban Studies.
    Eirtö, Tatiana
    Department of Social Research, University of Turku, Turku, Finland.
    Karlsson, Martin
    Örebro University, School of Humanities, Education and Social Sciences. Urban Studies.
    Ruoppila, Sampo
    Department of Social Research, University of Turku, Turku, Finland.
    Thiel, Sarah-Kristin
    Austrian Institute of Technology, Vienna, Austria.
    Balancing Potential and Risk: The Living Lab Approach in Mobile Participation Research2017In: Lecture Notes in Computer Science, ISSN 0302-9743, E-ISSN 1611-3349, no 10429, p. 12-23Article in journal (Refereed)
    Abstract [en]

    Living labs as a research approach have been said to hold many promises regarding the evaluation of state-of-the art technologies in real-world contexts, for instance by allowing close cooperation with various stakeholders. At the same time, a living lab approach is connected with substantial complexity and increased risk. This paper elaborates on a conducted living lab with the objective to explore challenges and opportunities of mobile participation. For this purpose, a novel mobile application enabling interaction between citizens and city authorities was tested over a period of five months in Turku, Finland. In this paper, we describe identified risks associated with a living lab approach to mobile participation research. We conclude with an overall evaluation regarding the appropriateness of the living lab approach within the e-participation research field and provide recommendations on how to balance potential and risk in future projects. 

  • 2.
    Afsharmazayejani, R.
    et al.
    Shahid Bahonar University of Kerman, Kerman, Iran.
    Yazdanpanah, F.
    Vali-e-Asr University, Rafsanjan, Iran.
    Rezaei, A.
    Northwestern University, Evanston, United States.
    Alaei, M.
    Vali-e-Asr University, Rafsanjan, Iran.
    Daneshtalab, Masoud
    Mälardalen University, School of Innovation, Design and Engineering, Embedded Systems.
    HoneyWiN: Novel honeycomb-based wireless NoC architecture in many-core era2018In: Lecture Notes in Computer Science, ISSN 0302-9743, E-ISSN 1611-3349, Vol. 10824 LNCS, p. 304-316Article in journal (Refereed)
    Abstract [en]

    Although NoC-based systems with many cores are commercially available, their multi-hop nature has become a bottleneck on scaling performance and energy consumption parameters. Alternatively, hybrid wireless NoC provides a postern by exploiting single-hop express links for long-distance communications. Also, there is a common wisdom that grid-like mesh is the most stable topology in conventional designs. That is why almost all of the emerging architectures had been relying on this topology as well. In this paper, first we challenge the efficiency of the grid-like mesh in emerging systems. Then, we propose HoneyWiN, a hybrid reconfigurable wireless NoC architecture that relies on the honeycomb topology. The simulation results show that on average HoneyWiN saves 17% of energy consumption while increases the network throughput by 10% compared to its wireless mesh counterpart. 

  • 3.
    Allwood, Jens
    et al.
    University of Borås, School of Business and IT.
    Grammer, Karl
    Kopp, Stefan
    Ahlsén, Elisabeth
    University of Borås, School of Business and IT.
    Stocksmeier, Thorsten
    Modeling embodied feedback with virtual humans2008In: Lecture Notes in Computer Science, ISSN 0302-9743, E-ISSN 1611-3349, Vol. 4930Article in journal (Refereed)
  • 4.
    Altafini, Claudio
    et al.
    SISSA-ISAS International School for Advanced Studies.
    Speranzon, Alberto
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Johansson, Karl Henrik
    KTH, Superseded Departments, Signals, Sensors and Systems.
    Hybrid control of a truck and trailer vehicle2002In: Lecture Notes in Computer Science, ISSN 0302-9743, E-ISSN 1611-3349, Vol. 2289, p. 21-34Article in journal (Other academic)
    Abstract [en]

    A hybrid control scheme is proposed for the stabilization of backward driving along simple paths for a miniature vehicle composed of a truck and a two-axle trailer. When reversing, the truck and trailer can be modelled as an unstable nonlinear system with state and input saturations. Due to these constraints the system is impossible to globally stabilize with standard smooth control techniques, since some initial states necessarily lead to that the so called jack-knife locks between the truck and the trailer. The proposed hybrid control method, which combines backward and forward motions, provide a global attractor to the desired reference trajectory. The scheme has been implemented and successfully evaluated on a radio-controlled vehicle. Results from experimental trials are reported.

  • 5.
    Ardelius, John
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication: Services and Infrastucture, Software and Computer Systems, SCS.
    Meji­as, B.
    Modeling the performance of ring based DHTs in the presence of network address translators2011In: Lecture Notes in Computer Science, ISSN 0302-9743, E-ISSN 1611-3349, Vol. 6723, p. 15-28Article in journal (Refereed)
    Abstract [en]

    Dealing with Network Address Translators (NATs) is a central problem in many peer-to-peer applications on the Internet today. However, most analytical models of overlay networks assume the underlying network to be a complete graph, an assumption that might hold in evaluation environments such as PlanetLab but turns out to be simplistic in practice. In this work we introduce an analytical network model where a fraction of the communication links are unavailable due to NATs. We investigate how the topology induced by the model affects the performance of ring based DHTs. We quantify two main performance issues induced by NATs namely large lookup inconsistencies and increased break-up probability, and suggest how theses issues can be addressed. The model is evaluated using discrete based simulation for a wide range of parameters.

  • 6.
    Aurell, Erik
    et al.
    KTH, School of Engineering Sciences (SCI), Physics.
    El-Ansary, Sameh
    KTH, School of Engineering Sciences (SCI), Physics.
    A physics-style approach to scalability of distributed systems2005In: Lecture Notes in Computer Science, ISSN 0302-9743, E-ISSN 1611-3349, Vol. 3267, p. 266-272Article in journal (Refereed)
    Abstract [en]

    Is it possible to treat large scale distributed systems as physical systems? The importance of that question stems from the fact that the behavior of many P2P systems is very complex to analyze analytically, and simulation of scales of interest can be prohibitive. In Physics, however, one is accustomed to reasoning about large systems. The limit of very large systems may actually simplify the analysis. As a first example, we here analyze the effect of the density of populated nodes in an identifier space in a P2P system. We show that while the average path length is approximately given by a function of the number of populated nodes, there is a systematic effect which depends on the density. In other words, the dependence is both on the number of address nodes and the number of populated nodes, but only through their ratio. Interestingly, this effect is negative for finite densities, showing that an amount of randomness somewhat shortens average path length.

  • 7.
    Balliu, Musard
    et al.
    KTH, School of Computer Science and Communication (CSC), Theoretical Computer Science, TCS.
    Mastroeni, Isabella
    A Weakest Precondition Approach to Robustness2010In: Lecture Notes in Computer Science, ISSN 0302-9743, E-ISSN 1611-3349, Vol. 6340, no PART 1, p. 261-297Article in journal (Refereed)
    Abstract [en]

    With the increasing complexity of information management computer systems, security becomes a real concern. E-government, web-based financial transactions or military and health care information systems are only a few examples where large amount of information can reside on different hosts distributed worldwide. It is clear that any disclosure or corruption of confidential information in these contexts can result fatal. Information flow controls constitute an appealing and promising technology to protect both data confidentiality and data integrity. The certification of the security degree of a program that runs in untrusted environments still remains an open problem in the area of language-based security. Robustness asserts that an active attacker, who can modify program code in some fixed points (holes), is unable to disclose more private information than a passive attacker, who merely observes unclassified data. In this paper, we extend a method recently proposed for checking declassified non-interference in presence of passive attackers only, in order to check robustness by means of weakest precondition semantics. In particular, this semantics simulates the kind of analysis that can be performed by an attacker, i.e., from public output towards private input. The choice of semantics allows us to distinguish between different attacks models and to characterize the security of applications in different scenarios. Our results are sound to address confidentiality and integrity of software running in untrusted environments where different actors can distrust one another. For instance, a web server can be attacked by a third party in order to steal a session cookie or hijack clients to a fake web page.

  • 8.
    Björnsson, Gunnar
    et al.
    Umeå University, Faculty of Arts, Department of historical, philosophical and religious studies.
    Shanklin, Robert
    ‘Must’, ‘Ought’ and the Structure of Standards2014In: Lecture Notes in Computer Science, ISSN 0302-9743, E-ISSN 1611-3349, no 8554, p. 33-48Article in journal (Refereed)
    Abstract [en]

    This paper concerns the semantic difference between strong and weak necessity modals. First we identify a number of explananda: their well-known intuitive difference in strength between ‘must’ and ‘ought’ as well as differences in connections to probabilistic considerations and acts of requir- ing and recommending. Here we argue that important extant analyses of the semantic differences, though tailored to account for some of these aspects, fail to account for all. We proceed to suggest that the difference between ’ought’ and ’must’ lies in how they relate to scalar and binary standards. Briefly put, must(φ) says that among the relevant alternatives, φ is selected by the relevant binary standard, whereas ought(φ) says that among the relevant alternatives, φ is selected by the relevant scale. Given independently plausible assumptions about how standards are provided by context, this explains the relevant differ- ences discussed.

  • 9.
    Camelo, Guilherme Antonio
    et al.
    Federal University of Rio Grande do Sul, Porto Alegre, Brazil.
    Recena Menezes, Maria Luiza
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS). Federal University of Rio Grande do Sul, Porto Alegre, Brazil.
    Pinheiro Sant'Anna, Anita
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS).
    Vicari, Rosa Maria
    Federal University of Rio Grande do Sul, Porto Alegre, Brazil.
    Pereira, Carlos Eduardo
    Federal University of Rio Grande do Sul, Porto Alegre, Brazil.
    Control of Smart Environments Using Brain Computer Interface Based on Genetic Algorithm2016In: Lecture Notes in Computer Science, ISSN 0302-9743, E-ISSN 1611-3349, Vol. 9622, p. 773-781Article in journal (Refereed)
    Abstract [en]

    This work deals with the development of an interface to control a smart conference room using passive BCI (Brain Computer Interface). It compares a genetic algorithm developed in a previous project to control the smart conference room with a random control algorithm. The system controls features of the conference room such as air conditioner, lightning systems, electric shutters, entertainment devices, etc. The parameters of the algorithm are extracted from users biosignal using Emotiv Epoc Headset while the user performs an attention test. The tests indicate that the decisions made by the genetic algorithm lead to better results, but in a single execution cannot be considered an effective optimization algorithm. © Springer-Verlag Berlin Heidelberg 2016.

  • 10.
    Cappelen, Birgitta
    et al.
    Oslo School of Architecture and Design.
    Andersson, Anders-Petter
    Kristianstad University, School of Health and Society.
    Musicking tangibles for empowerment2012In: Lecture Notes in Computer Science, ISSN 0302-9743, E-ISSN 1611-3349, Vol. 7382, p. 254-261Article in journal (Refereed)
    Abstract [en]

    In this paper we present a novel approach towards understanding and design of interactive music technology for people with special needs. The health effects of music are well documented, but very little research has been done and interactive music technology been developed, for Music Therapy and health improvement in everyday situations. Further, the music technology that has been used, exploits very little of the potential current computer technology has to offer the Music and Health and Music Therapy fields, because it is designed and used based on a very narrow perspective on technology and its potential. We present and argue for a broader understanding of music technology for empowerment and health improvement, building on a multidisciplinary approach and combining perspectives from Tangible interaction design with empowerment and resource oriented Music Therapy. We call this concept MusickingTangibles, inspired by the musicologist Christopher Small's important term "musicking". We further present two Musicking Tangibles we have designed, and argue for their empowering qualities based on user observations.

  • 11. Carlsson, Bengt
    et al.
    Gustavsson, Rune
    Arms Race Within Information Ecosystems2001In: Lecture Notes in Computer Science, ISSN 0302-9743, E-ISSN 1611-3349, Vol. 2182, p. 202-207Article in journal (Refereed)
    Abstract [en]

    Interacting agents of exploiters and users within an information ecosystem may be regarded both as biological beings and as part of an economic system of infohabitants. A protection system can be implemented as a filter governing the access to assets. Typically we will have a chain of attacks and countermeasures concerning this access to the desired assets. We model this process as an arms race. We base our model on a process model of a protection system based on exposure time. A user's reaction against an exploiter measure could either be a direct response to the measure or an attempt to anticipate future attacks by more general means of defeating the protection of the exploiter agent. When anticipating future attacks and countermeasures, both users and exploiters will improve their methods and tools due to an arms race. Our arms race model refines the competition as modeled in computational markets to model aspects which typically arise when societies grow beyond what can be controlled in a centralized manner. A dynamic, evolving and robust ecosystem of autonomous agents is sometimes a preferred and possible outcome of the arms race as a hardening process.

  • 12.
    Clarke, Dave
    et al.
    CWI.
    Wrigstad, Tobias
    Purdue University.
    Östlund, Johan
    Purdue University.
    Broch Johnsen, Einar
    University of Olso.
    Minimal Ownership for Active Objects2008In: Lecture Notes in Computer Science, ISSN 0302-9743, E-ISSN 1611-3349Article in journal (Refereed)
    Abstract [en]

    Active objects offer a structured approach to concurrency, encapsulating both unshared state and a thread of control. For efficient data transfer, data should be passed by reference whenever possible, but this introduces aliasing and undermines the validity of the active objects. This paper proposes a minimal variant of ownership types that preserves the required race freedom invariant yet enables data transfer by reference between active objects (that is, without copying) in many cases, and a cheap clone operation where copying is necessary. Our approach is general and should be adaptable to several existing active object systems.

  • 13. Clemm, A.
    et al.
    Granville, L. Z.
    Stadler, Rolf
    KTH, School of Electrical Engineering (EES), Communication Networks.
    Managing virtualization of networks and services2015In: Lecture Notes in Computer Science, ISSN 0302-9743, E-ISSN 1611-3349, Vol. 4785Article in journal (Refereed)
  • 14.
    Dam, Mads
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Regular SPKI2005In: Lecture Notes in Computer Science, ISSN 0302-9743, E-ISSN 1611-3349, Vol. 3364, p. 134-152Article in journal (Refereed)
    Abstract [en]

    SPKI is a certificate-based framework for authorisation in distributed systems. The SPKI framework is extended by an iteration construct, essentially Kleene star, to express constraints on delegation chains. Other possible applications, not explored in the paper, include multidomain network routing path constraints. The main decision problems for the extended language are shown to correspond to regular language membership and containment respectively. To support an efficient decision algorithm in both cases we give a sound and complete inference system for a fragment of the language which is decidable in polynomial time. We finally show how to use the extended syntax to represent constrained delegation in SPKI.

  • 15.
    Danylenko, Antonina
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Computer Science, Physics and Mathematics.
    Löwe, Welf
    Linnaeus University, Faculty of Science and Engineering, School of Computer Science, Physics and Mathematics.
    Adaptation of Legacy Codes to Context-Aware Composition Using Aspect-Oriented Programming2012In: Lecture Notes in Computer Science, ISSN 0302-9743, E-ISSN 1611-3349, Vol. 7306, p. 68-85Article in journal (Refereed)
    Abstract [en]

    The context-aware composition approach (CAC) has shown to improve the performance of object-oriented applications on modern multi-core hardware by selecting between different (sequential and parallel) component variants in different (call and hardware) contexts. However, introducing CAC in legacy applications can be time-consuming and requires quite some effort for changing and adapting the existing code.We observe that CAC-concerns, like offline component variant profiling and runtime selection of the champion variant, can be separated from the legacy application code. We suggest separating and reusing these CAC concerns when introducing CAC to different legacy applications.

    For automating this process, we propose an approach based on Aspect-Oriented Programming (AOP) and Reflective Programming. It shows that manual adaptation to CAC requires more programming than the AOP-based approach; almost three times in our experiments. Moreover, the AOP-based approach speeds up the execution time of the legacy code, in our experiments by factors of up to 2.3 and 3.4 on multi-core machines with two and eight cores, respectively. The AOP based approach only introduces a small runtime overhead compared to the manually optimized CAC approach. For different problems, this overhead is about 2-9% of the manual adaptation approach. These results suggest that AOP-based adaptation can effectively adapt legacy applications to CAC which makes them running efficiently even on multi-core machines.

  • 16.
    de Fréin, Ruairí
    Telecommunications Software and Systems Group, Waterford Institute of Technology, Ireland.
    Formal Concept Analysis via Atomic Priming2013In: Lecture Notes in Computer Science, ISSN 0302-9743, E-ISSN 1611-3349, Vol. 7880, p. 92-108Article in journal (Refereed)
    Abstract [en]

    Formal Concept Analysis (FCA) looks to decompose a matrix of objects-attributes into a set of sparse matrices capturing the underlying structure of a formal context. We propose a Rank Reduction (RR) method to prime approximate FCAs, namely RRFCA. While many existing FCA algorithms are complete, lectic ordering of the lattice may not minimize search/decomposition time. Initially, RRFCA decompositions are not unique or complete; however, a set of good closures with high support is learned quickly, and then, made complete. RRFCA has its novelty in that we propose a new multiplicative two-stage method. First, we describe the theoretical foundations underpinning our RR approach. Second, we provide a representative exemplar, showing how RRFCA can be implemented. Further experiments demonstrate that RRFCA methods are efficient, scalable and yield time-savings. We demonstrate the resulting methods lend themselves to parallelization.

  • 17.
    de Fréin, Ruairí
    Telecommunications Software and Systems Group, Waterford Institute of Technology, Ireland.
    Multilayered, Blocked Formal Concept Analyses for Adaptive Image Compression2014In: Lecture Notes in Computer Science, ISSN 0302-9743, E-ISSN 1611-3349, Vol. 8478, p. 251-267Article in journal (Refereed)
    Abstract [en]

    Formal Concept Analysis (FCA) decomposes a matrix into a set of sparse matrices capturing its underlying structure. A similar task for real-valued data, transform coding, arises in image compression. Existing cosine transform coding for JPEG image compression uses a fixed, decorrelating transform; however, compression is limited as images rarely consist of pure cosines. The question remains whether an FCA adaptive transform can be applied to image compression. We propose a multi-layer FCA (MFCA) adaptive ordered transform and Sequentially Sifted Linear Programming (SSLP) encoding pair for adaptive image compression. Our hypothesis is that MFCA’s sparse linear codes (closures) for natural scenes, are a complete family of ordered, localized, oriented, bandpass receptive fields, predicted by models of the primary visual cortex. Results on real data demonstrate that adaptive compression is feasible. These initial results may play a role in improving compression rates and extending the applicability of FCA to real-valued data.

  • 18.
    de Fréin, Ruairí
    et al.
    Waterford Institute of Technology, Ireland.
    Xu, Biao
    Waterford Institute of Technology, Ireland.
    Robson, Eric
    Waterford Institute of Technology, Ireland.
    Distributed Formal Concept Analysis Algorithms Based on an Iterative MapReduce Framework2012In: Lecture Notes in Computer Science, ISSN 0302-9743, E-ISSN 1611-3349, Vol. 7278, p. 292-308Article in journal (Refereed)
    Abstract [en]

    While many existing formal concept analysis algorithms are efficient, they are typically unsuitable for distributed implementation. Taking the MapReduce (MR) framework as our inspiration we introduce a distributed approach for performing formal concept mining. Our method has its novelty in that we use a light-weight MapReduce runtime called Twister which is better suited to iterative algorithms than recent distributed approaches. First, we describe the theoretical foundations underpinning our distributed formal concept analysis approach. Second, we provide a representative exemplar of how a classic centralized algorithm can be implemented in a distributed fashion using our methodology: we modify Ganter’s classic algorithm by introducing a family of MR⋆ algorithms, namely MRGanter and MRGanter+ where the prefix denotes the algorithm’s lineage. To evaluate the factors that impact distributed algorithm performance, we compare our MR∗ algorithms with the state-of-the-art. Experiments conducted on real datasets demonstrate that MRGanter+ is efficient, scalable and an appealing algorithm for distributed problems.

  • 19. Dowling, Jim
    et al.
    Taïani, F.
    Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics): Preface2013In: Lecture Notes in Computer Science, ISSN 0302-9743, E-ISSN 1611-3349, p. VII-VIIIArticle in journal (Refereed)
  • 20.
    Eklund, Patrik
    et al.
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Georgsson, Fredrik
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Unravelling the thrill of metric image spaces1999In: Lecture Notes in Computer Science, ISSN 0302-9743, E-ISSN 1611-3349, Vol. 1568, p. 275-285Article in journal (Refereed)
    Abstract [en]

    In this paper we focus on distances between textures. and develop metrics on image spaces in contexts of image transformations. Given a metric on the range space, we can generate the initial topology for the domain space. For this topology we can obtain a corresponding metric using well-known metrization constructions, also providing granularity of the metrics. Examples are drawn front the Spatial Gray Level Dependency (SGLD) transformation and the application domain is texture recognition in medical imaging.

  • 21.
    El-Ansary, Sameh
    et al.
    Swedish Institute of Computer Science.
    Onana Alima, Luc
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Brand, Per
    Swedish Institute of Computer Science.
    Haridi, Seif
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Efficient broadcast in structured P2P networks2003In: Lecture Notes in Computer Science, ISSN 0302-9743, E-ISSN 1611-3349, Vol. 2735, p. 304-314Article in journal (Refereed)
    Abstract [en]

    In this position paper, we present an efficient algorithm for performing a broadcast operation with minimal cost in structured DHT-based P2P networks. In a system of N nodes, a broadcast message originating at an arbitrary node reaches all other nodes after exactly N - 1 messages. We emphasize the perception of a class of DHT systems as a form of distributed k-ary search and we take advantage of that perception in constructing a spanning tree that is utilized for efficient broadcasting. We consider broadcasting as a basic service that adds to existing DHTs the ability to search using arbitrary queries as well as dissiminate/collect global information.

  • 22.
    Eriksen, Niklas
    Dept. of Mathematics, Royal Institute of Technology, Stockholm.
    Approximating the expected number of inversions given the number of breakpoints2002In: Lecture Notes in Computer Science, ISSN 0302-9743, E-ISSN 1611-3349, Vol. 2452, p. 316-330Article in journal (Refereed)
    Abstract [en]

    We look at a problem with motivation from computational biology: Given the number of breakpoints in a permutation (representing a gene sequence), compute the expected number of inversions that have occured. For this problem, we obtain an analytic approximation that is correct within a percent or two. For the inverse problem, computing the expected number of breakpoints after any number of inversions, we obtain an analytic approximation with an error of less than a hundredth of a breakpoint.

  • 23.
    Fagerström, Daniel
    KTH, School of Computer Science and Communication (CSC), Computer Vision and Active Perception, CVAP.
    Spatio-temporal Scale-Spaces2007In: Lecture Notes in Computer Science, ISSN 0302-9743, E-ISSN 1611-3349, Vol. 4485, p. 326-337Article in journal (Refereed)
    Abstract [en]

    A family of spatio-temporal scale-spaces suitable for a moving observer is developed. The scale-spaces are required to be time causal for being usable for real time measurements, and to be velocity adapted , i.e. to have Galilean covariance to avoid favoring any particular motion. Furthermore standard scale-space axioms: linearity, positivity, continuity, translation invariance, scaling covariance in space and time, rotational invariance in space and recursivity are used. An infinitesimal criterion for scale-spaces is developed, which simplifies calculations and makes it possible to define scale spaces on bounded regions. We show that there are no temporally causal Galilean scale-spaces that are semigroups acting on space and time, but that there are such scale-spaces that are semigroups acting on space and memory (where the memory is the scale-space). The temporally causal scale-space is a time-recursive process using current input and the scale-space as state, i.e. there is no need for storing earlier input. The diffusion equation acting on the memory with the input signal as boundary condition, is a member of this family of scale spaces and is special in the sense that its generator is local.

  • 24.
    Fan, Yuantao
    et al.
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR - Center for Applied Intelligent Systems Research.
    Aramrattana, Maytheewat
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR - Center for Applied Intelligent Systems Research.
    Shahbandi, Saeed Gholami
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR - Center for Applied Intelligent Systems Research.
    Nemati, Hassan Mashad
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR - Center for Applied Intelligent Systems Research.
    Åstrand, Björn
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS), CAISR - Center for Applied Intelligent Systems Research.
    Infrastructure Mapping in Well-Structured Environments Using MAV2016In: Lecture Notes in Computer Science, ISSN 0302-9743, E-ISSN 1611-3349, Vol. 9716, p. 116-126Article in journal (Refereed)
    Abstract [en]

    In this paper, we present a design of a surveying system for warehouse environment using low cost quadcopter. The system focus on mapping the infrastructure of surveyed environment. As a unique and essential parts of the warehouse, pillars from storing shelves are chosen as landmark objects for representing the environment. The map are generated based on fusing the outputs of two different methods, point cloud of corner features from Parallel Tracking and Mapping (PTAM) algorithm with estimated pillar position from a multi-stage image analysis method. Localization of the drone relies on PTAM algorithm. The system is implemented in Robot Operating System(ROS) and MATLAB, and has been successfully tested in real-world experiments. The result map after scaling has a metric error less than 20 cm. © Springer International Publishing Switzerland 2016.

  • 25. Fiedler, Markus
    et al.
    Isaksson, Lennart
    Chevul, Stefan
    Measurements and analysis of application-perceived throughput via mobile links2011In: Lecture Notes in Computer Science, ISSN 0302-9743, E-ISSN 1611-3349, Vol. 5233, p. 37-69Article in journal (Refereed)
    Abstract [en]

    Application-perceived throughput plays a major role for the performance of networked applications and user experience and thus, for network selection decisions. To support the latter, this tutorial paper investigates the process of user-perceived throughput in GPRS and UMTS systems seen over rather small averaging intervals, based on test traffic mimicking the needs of streaming applications, and analyzes the results with aid of summary statistics. These results reveal a clear influence of the network, seen from variations and autocorrelation of application-perceived throughput mostly on the one-second time scale and indicate that applications have to cope with significant jitter when trying to exploit the nominal throughputs. In GPRS, the promised average throughputs are not reached in downlink direction; instead, significant packet loss occurs. Furthermore, with aid of causality arguments for an equivalent bottleneck, bounds for the extra delay of the first packet sent via mobile links is derived from throughput measurements.

  • 26. Fodor, Gabor
    et al.
    Telek, Miklós
    Performance analysis of the uplink of a CDMA cell supporting elastic services2005In: Lecture Notes in Computer Science, ISSN 0302-9743, E-ISSN 1611-3349, Vol. 3462, p. 205-216Article in journal (Refereed)
    Abstract [en]

    We consider a single cell of a multi-service CDMA network, in which some of the service classes are explicit rate controlled. We call these elastic service classes. The instantaneous bit rate of elastic services is dynamically adjusted between a minimum and maximum value such that the system always remains work conserving. We develop a Markov model that allows us to study the impact of such state dependent (dynamic) rate control on the class-wise blocking probabilities and the first two moments of the holding times. We conclude that dynamic (state dependent) rate adjustment decreases the class-wise blocking probabilities and only moderately increases the expectation and the second moment of the time spent in the system.

  • 27. Fodor, Gabor
    et al.
    Telek, Miklós
    Badia, Leonardo
    On the tradeoff between blocking and dropping probabilities in CDMA networks supporting elastic services2006In: Lecture Notes in Computer Science, ISSN 0302-9743, E-ISSN 1611-3349, Vol. 3976, p. 954-965Article in journal (Refereed)
    Abstract [en]

    This paper is a sequel of previous work, in which we proposed a model and computational technique to calculate the Erlang capacity of a single CDMA cell that supports elastic services. The present paper extends that base model by taking into account two important features of CDMA. First, we capture the impact of soft blocking by modeling the neighbor cell interference as a lognormally distributed random variable. Secondly, we model the impact of the outage by taking into account that in-progress sessions can be dropped with a probability that depends on the current load in the system. We then consider a system with elastic and rigid service classes and analyze the trade-off between the total (soft and hard) blocking probabilities on the one hand and the throughput and the session drop probabilities on the other.

  • 28.
    Frintrop, Simone
    KTH, School of Computer Science and Communication (CSC), Computer Vision and Active Perception, CVAP.
    VOCUS: A visual attention system for object detection and goal-directed search2006In: Lecture Notes in Computer Science, ISSN 0302-9743, E-ISSN 1611-3349, p. 1-228Article in journal (Refereed)
    Abstract [en]

    Visual attention is a mechanism in human perception which selects relevant regions from a scene and provides these regions for higher-level processing as object recognition. This enables humans to act effectively in their environment despite the complexity of perceivable sensor data. Computational vision systems face the same problem as humans: there is a large amount of information to be processed and to achieve this efficiently, maybe even in real-time for robotic applications, the order in which a scene is investigated must be determined in an intelligent way. A promising approach is to use computational attention systems that simulate human visual attention. This monograph introduces the biologically motivated computational attention system VOCUS (Visual Object detection with a Computational attention System) that detects regions of interest in images. It operates in two modes, in an exploration mode in which no task is provided, and in a search mode with a specified target. In exploration mode, regions of interest are defined by strong contrasts (e.g., color or intensity contrasts) and by the uniqueness of a feature. For example, a black sheep is salient in a flock of white sheep. In search mode, the system uses previously learned information about a target object to bias the saliency computations with respect to the target. In various experiments, it is shown that the target is on average found with less than three fixations, that usually less than five training images suffice to learn the target information, and that the system is mostly robust with regard to viewpoint changes and illumination variances. Furthermore, we demonstrate how VOCUS profits from additional sensor data: we apply the system to depth and reflectance data from a 3D laser scanner and show the advantages that the laser modes provide. By fusing the data of both modes, we demonstrate how the system is able to consider distinct object properties and how the flexibility of the system increases by considering different data. Finally, the regions of interest provided by VOCUS serve as input to a classifier that recognizes the object in the detected region. We show how and in which cases the classification is sped up and how the detection quality is improved by the attentional front-end. This approach is especially useful if many object classes have to be considered, a frequently occurring situation in robotics. VOCUS provides a powerful approach to improve existing vision systems by concentrating computational resources to regions that are more likely to contain relevant information. The more the complexity and power of vision systems increase in the future, the more they will profit from an attentional front-end like VOCUS.

  • 29.
    Fu, Jing
    et al.
    KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre. KTH, School of Electrical Engineering (EES), Communication Networks.
    Sjödin, Peter
    KTH, School of Information and Communication Technology (ICT).
    Karlsson, Gunnar
    KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre. KTH, School of Electrical Engineering (EES), Communication Networks.
    Traffic Engineering and Routing in IP Networks with Centralized Control2008In: Lecture Notes in Computer Science, ISSN 0302-9743, E-ISSN 1611-3349, Vol. 4982, p. 633-641Article in journal (Refereed)
    Abstract [en]

    There have been research initiatives in centralized control recently, which advocatethat the control of an autonomous system (AS) should be performed in acentralized fashion. In this paper, we propose an approach to perform traffic engineeringand routing in networks with centralized control, named LP-redirect.LP-redirect is based on an efficient formulation of linear programming (LP) thatreduces the number of variables and constraints. As LP is not fast enough for runtimerouting, LP-redirect uses a fast scheme to recompute routing paths when anetwork topology changes. The performance evaluation of LP-redirect shows thatit is more efficient in both traffic engineering and computation than an approachusing optimized link weights. In addition, LP-redirect is suitable for runtime trafficengineering and routing.

  • 30. G, Fodor
    On scheduling and interference coordination policies for multicell OFDMA networks2007In: Lecture Notes in Computer Science, ISSN 0302-9743, E-ISSN 1611-3349, Vol. 4479, p. 488-499Article in journal (Refereed)
    Abstract [en]

    In orthogonal frequency division multiple access systems there is an intimate relationship between the packet scheduler and the inter-cell interference coordination (ICIC) functionalities: they determine the set of frequency channels (sub-carriers) that are used to carry the packets of in-progress sessions. In this paper we build on previous work - in which we compared the so called random and coordinated ICIC policies - and analyze three packet scheduling methods. The performance measures of interest are the session blocking probabilities and the overall throughput. We find that the performance of the so-called Fifty-Fifty and What-It-Wants scheduling policies is improved by coordinated sub-carrier allocation, especially in poor signal-to-noise-and-interference situations. The performance of the All-Or-Nothing scheduler is practically insensitive to the choice of the sub-carrier allocation policy.

  • 31. G, Fodor
    et al.
    K, El-Malki
    D, Partain
    Closing the gap between industry, academia and users: Is there a need for QoS in wireless systems?2005In: Lecture Notes in Computer Science, ISSN 0302-9743, E-ISSN 1611-3349, Vol. 3552, p. 375-378Article in journal (Refereed)
    Abstract [en]

    In this short paper we make the point that although there may be a gap between academic and industrial research in the area of quality of service (QoS), this gap can be narrowed. In order for this to happen, it is important that the academic and industrial players jointly make an effort to better understand business drivers and end user needs and analyze how networks are used and how they are likely to evolve. That is, understanding the key drivers (the "why"-s) in the QoS area is the key in bringing academic and industrial research (that aims to answer the "how"-s) closer to each other.

  • 32.
    Gil de la Iglesia, Didac
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Computer Science, Physics and Mathematics.
    Milrad, Marcelo
    Linnaeus University, Faculty of Science and Engineering, School of Computer Science, Physics and Mathematics.
    Andersson, Jesper
    Linnaeus University, Faculty of Science and Engineering, School of Computer Science, Physics and Mathematics.
    Software Requirements to Support QoS in Collaborative M-Learning Activities2012In: Lecture Notes in Computer Science, ISSN 0302-9743, E-ISSN 1611-3349, Vol. 7493, p. 176-183Article in journal (Refereed)
    Abstract [en]

    The use of collaborative activities in education has proven to be an effective way to enhance students’ learning outcomes by in- creasing their engagement and motivating discussions on the learning topics under exploration. In the field of Technology Enhanced Learn- ing (TEL), the use of information and communication technologies has been extensively studied to provide alternative methods to support col- laborative learning activities, combining different applications and tools. Mobile learning, a subset of TEL, has become a prominent area of re- search as it offers promising tools to enhance students’ collaboration and it provides alternative views for teaching and learning subject matter in relevant and authentic scenarios. While many studies have focused on the pedagogical opportunities provided by mobile technologies, fewer are the efforts looking at technological related aspects. Hardware and software issues in this field still remain as challenges that require a deeper level of study and analysis. This paper presents and discusses the findings of a deep analysis based on the outcomes of three mobile collaborative learning activities and their requirements. These results have helped us to identify a number of arising challenges that need to be addressed in order to warranty Quality of Service (QoS) in these collaborative M- learning activities. Moreover, the paper offers a view on current practices in M-learning activities, which evidences the lack of research addressing software engineering aspects in mobile collaborative learning. 

  • 33.
    Gonzalez Prieto, Alberto
    et al.
    KTH, School of Electrical Engineering (EES), Communication Networks.
    Stadler, Rolf
    KTH, School of Electrical Engineering (EES), Communication Networks.
    Monitoring Flow Aggregates with Controllable Accuracy2007In: Lecture Notes in Computer Science, ISSN 0302-9743, E-ISSN 1611-3349, Vol. 4787, p. 64-75Article in journal (Refereed)
    Abstract [en]

    In this paper, we show the feasibility of real-time flow monitoringwith controllable accuracy in today’s IP networks. Our approach is based onNetflow and A-GAP. A-GAP is a protocol for continuous monitoring ofnetwork state variables, which are computed from device metrics usingaggregation functions, such as SUM, AVERAGE and MAX. A-GAP isdesigned to achieve a given monitoring accuracy with minimal overhead. AGAPis decentralized and asynchronous to achieve robustness and scalability.The protocol incrementally computes aggregation functions inside the networkand, based on a stochastic model, it dynamically configures local filters thatcontrol the overhead and accuracy. We evaluate a prototype in a testbed of 16commercial routers and provide measurements from a scenario where theprotocol continuously estimates the total number of FTP flows in the network.Local flow metrics are read out from Netflow buffers and aggregated in realtime.We evaluate the prototype for the following criteria. First, the ability toeffectively control the trade off between monitoring accuracy and processingoverhead; second, the ability to accurately predict the distribution of theestimation error ; third, the impact of a sudden change in topology on theperformance of the protocol. The testbed measurements are consistent withsimulation studies we performed for different topologies and network sizes,which proves the feasibility of the protocol design, and, more generally, thefeasibility of effective and efficient real-time flow monitoring in large networkenvironments.

  • 34.
    Gorton, Dan
    KTH, School of Architecture and the Built Environment (ABE), Transport Science.
    IncidentResponseSim: An Agent-Based Simulation Tool for Risk Management of Online Fraud2015In: Lecture Notes in Computer Science, ISSN 0302-9743, E-ISSN 1611-3349, Vol. 9417, p. 172-187Article in journal (Refereed)
    Abstract [en]

    IncidentResponseSim is a multi-agent-based simulation tool supporting risk management of online financial services, by performing a risk assessment of the quality of current countermeasures, in the light of the current and emerging threat environment. In this article, we present a set of simulations using incident response trees in combination with a quantitative model for estimating the direct economic consequences. The simulations generate expected fraud, and conditional fraud value at risk, given a specific fraud scenario. Additionally, we present how different trojan strategies result in different conditional fraud value at risk, given the underlying distribution of wealth in the online channel, and different levels of daily transaction limits. Furthermore, we show how these measures can be used together with return on security investment calculations to support decisions about future security investments.

  • 35.
    Hagsand, Olof
    et al.
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Más, Ignacio
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Marsh, Ian
    Swedish Institute of Computer Science.
    Karlsson, Gunnar
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Self-Admission Control for IP Telephony using Early Quality Estimation2004In: Lecture Notes in Computer Science, ISSN 0302-9743, E-ISSN 1611-3349, Vol. 3042, p. 381-391Article in journal (Refereed)
    Abstract [en]

    If quality of service could be provided at the transport or the application layer, then it might be deployed simply by software upgrades, instead of requiring a complete upgrade of the network infrastructure. In this paper, we propose a self-admission control scheme that does not require any network support or external monitoring schemes. We apply the admission control scheme to IP telephony as it is an important application benefiting from admission control. We predict the quality of the call by observing the packet loss over a short initial period using an in-band probing mechanism. The quality prediction is then used by the application to continue or to abort the call. Using over 9500 global IP telephony measurements, we show that it is possible to accurately predict the quality of a call. Early rejection of sessions has the advantage of saving valuable network resources plus not disturbing the on-going calls.

  • 36.
    Hansen, Kjetil Falkenberg
    et al.
    KTH, School of Computer Science and Communication (CSC), Media Technology and Interaction Design, MID. KTH, School of Computer Science and Communication (CSC), Speech, Music and Hearing, TMH, Music Acoustics.
    Bresin, Roberto
    KTH, Superseded Departments, Speech, Music and Hearing.
    Analysis of a genuine scratch performance2004In: Lecture Notes in Computer Science, ISSN 0302-9743, E-ISSN 1611-3349, Vol. 2915, p. 477-478Article in journal (Refereed)
    Abstract [en]

    The art form of manipulating vinyl records done by disc jockeys (DJs) is called scratching, and has become very popular since its start in the seventies. Since then turntables are commonly used as expressive musical instruments in several musical genres. This phenomenon has had a serious impact on the instrument-making industry, as the sales of turntables and related equipment have boosted. Despite of this, the acoustics of scratching has been barely studied until now. In this paper, we illustrate the complexity of scratching by measuring the gestures of one DJ during a performance. The analysis of these measurements is important to consider in the design of a scratch model.

  • 37.
    Hansson, Sven Ove
    KTH, School of Architecture and the Built Environment (ABE), Philosophy and History of Technology, Philosophy.
    Deontic diversity2014In: Lecture Notes in Computer Science, ISSN 0302-9743, E-ISSN 1611-3349, Vol. 8554 LNAI, p. 5-18Article in journal (Refereed)
    Abstract [en]

    It is commonly assumed that deontic logic concerns "the" logic of normative concepts. However, a close look at actual usage shows that the structural patterns of deontic notions differ between different usages. Some of these differences are difficult to discern in natural language, but may be easier to keep apart with the more precise tools of a formal language. We should use the resources of deontic logic to discover and distinguish between different meanings of the deontic terms in natural language. Some of the ingrained disagreements on postulates in deontic logic may be resolvable if we recognize that the different viewpoints correspond to different meanings of the normative terms of ordinary language.

  • 38.
    Helleboogh, Alexander
    et al.
    Katholieke University Leuven.
    Holvoet, Tom
    Katholieke University Leuven.
    Weyns, Danny
    Katholieke University Leuven.
    Berbers, Y.
    Katholieke University Leuven.
    Extending time management support for multi-agent systems2005In: Lecture Notes in Computer Science, ISSN 0302-9743, E-ISSN 1611-3349, Vol. 3415, p. 37-48Article in journal (Refereed)
    Abstract [en]

    Time management is essential when simulating multi-agent systems (MASs) as it allows consistent and repeatable simulation runs. So far, time management lacks support to express the timing requirements of a simulation explicitly and at an abstraction level appropriate for MAS developers. Moreover, integrating time management into a MAS requires the developer to alter the design of the MAS. In this paper, we first propose semantic duration models to capture timing requirements that reflect the semantics of MAS activities in an explicit model. Second, we present a time management infrastructure that starts from a semantic duration model description to integrate all time management functionality into a MAS transparently, i.e. without requiring the developer to alter the design of the MAS. We use aspect-oriented programming technology as it allows separation of concerns, a crucial software engineering requirement. As a case, we apply our approach to the Packet-World.

  • 39.
    Hjalmarsson, Anders
    et al.
    University of Borås, School of Business and IT.
    Rudmark, Daniel
    University of Borås, School of Business and IT.
    Lind, Mikael
    University of Borås, School of Business and IT.
    When Designers Are Not in Control: Experiences from Using Action Research to Improve Researcher-Developer Collaboration in Design Science Research2010In: Lecture Notes in Computer Science, ISSN 0302-9743, E-ISSN 1611-3349, Vol. 6105, p. 1-15Article in journal (Refereed)
    Abstract [en]

    Design science research (DSR) has received much attention in the past few years from the field of information systems. This paper argues that control in researcher-developer collaboration during artefact development has not yet received enough attention in design science research even though control is necessary for successful artefact instantiation.Experiences are presented from improving researcher-developer collaboration during DSR by using action research (AR) as means. These experiences are driven from the need to achieve meta-design control throughout the development of artefacts by non-researching system developers when DSR is performed in an authentic setting. The paper shows that the use of AR to both diagnose uncertainty and actively improve building activities may lead to sustainable improvements in researcher-developer collaboration, and hence achieve meta-design control in DSR performed in authentic development environments, as well as enhance progress in DSR methodology development.

  • 40. Ilie, Dragos
    et al.
    Popescu, Adrian
    Unicast QoS Routing in Overlay Networks2011In: Lecture Notes in Computer Science, ISSN 0302-9743, E-ISSN 1611-3349, Vol. 5233, p. 1017-1038Article in journal (Refereed)
    Abstract [en]

    The goal of quality of service (QoS) routing in overlay networks is to address deficiencies in today's Internet Protocol (IP) routing. This is achieved by application-layer protocols executed on end-nodes, which search for Alternate paths that can provide better QoS for the overlay hosts. In the first part of this paper we introduce fundamental concepts of QoS routing and the current state-of-the-art in overlay networks for QoS. In the remaining part of the paper we report performance results for the Overlay Routing Protocol (ORP) framework developed at Blekinge Institute of Technology (BTH) in Karlskrona, Sweden. The results show that QoS paths can be established and maintained as long as one is willing to accept a protocol overhead of maximum 1.5% of the network capacity.

  • 41.
    Jahnke, Isa
    et al.
    Umeå University, Faculty of Social Sciences, Department of applied educational science, Interactive Media and Learning (IML).
    Norqvist, Lars
    Umeå University, Faculty of Social Sciences, Department of applied educational science, Interactive Media and Learning (IML).
    Olsson, Andreas
    Umeå University, Faculty of Social Sciences, Department of applied educational science, Interactive Media and Learning (IML).
    Digital Didactical Designs in iPad-Classrooms2013In: Lecture Notes in Computer Science, ISSN 0302-9743, E-ISSN 1611-3349, Vol. 8095, p. 611-612Article in journal (Refereed)
    Abstract [en]

    Traditionally, Information and Communication Technology (ICT) "has been segregated from the normal teaching classroom" P[12], e.g. in computer labs. This has been changed with the advent of smaller devices like iPads. There is a shift from separating ICT and education to co-located settings in which digital technology becomes part of the classroom. This paper presents the results from a study about exploring digital didactical designs using iPads applied by teachers in schools. Classroom observations and interviews in iPad-classrooms in Danish schools have been done with the aim to provide empirical evidence on the co-evolutionary design of both, didactical designs and iPads. The Danish community Odder has 7 schools where around 200 teachers and 2,000 students aged 6-16 use iPads in a 1: 1 iPad-program. Three key aspects could be explored: The teachers' digital didactical designs embrace a) new learning goals where more than one correct answer exists, b) focus on producing knowledge in informal-in-formal learning spaces, c) making learning visible in different products (text, comics, podcasts etc.). The results show the necessity of rethinking traditional Didaktik towards Digital Didactics.

  • 42.
    Johansson, Pedher
    et al.
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Kressner, Daniel
    Semi-automatic generation of web-based computing environments for software libraries2002In: Lecture Notes in Computer Science, ISSN 0302-9743, E-ISSN 1611-3349, Vol. 2329, p. 872-880Article in journal (Refereed)
  • 43.
    Keyvani, Ali
    et al.
    University West, Department of Engineering Science, Division of Natural Sciences and Electrical and Surveying Engineering. University West, Department of Engineering Science, Research Enviroment Production Technology West.
    Lämkull, Dan
    Volvo Car Corporation, Gothenburg.
    Bolmsjö, Gunnar
    University West, Department of Engineering Science, Division of Production Engineering.
    Örtengren, Roland
    Chalmers University.
    Using methods-time measurement to connect digital humans and motion databases2013In: Lecture Notes in Computer Science, ISSN 0302-9743, E-ISSN 1611-3349, Vol. 8026, no Part 2, p. 343-352Article in journal (Refereed)
    Abstract [en]

    To simulate human motions in DHM tools, using techniques which are based on real human data is one promising solution. We have presented a solution in this study to connect motion databases with DHM tools. We have showed that using a motion database with MTM-based annotations is a promising way in order to synthesize natural looking motions. A platform consists of a Motion Database, a Motion Generator, and a DHM tool was introduced and tested. The results showed successful application of the presented platform in the designed test case. © 2013 Springer-Verlag.

  • 44.
    Krishnamurthy, Supriya
    et al.
    Swedish Institute of Computer Science.
    El-Ansary, Sameh
    Swedish Institute of Computer Science.
    Aurell, Erik
    KTH, School of Engineering Sciences (SCI), Physics.
    Haridi, Seif
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    A statistical theory of Chord under churn2005In: Lecture Notes in Computer Science, ISSN 0302-9743, E-ISSN 1611-3349, Vol. 3640, p. 93-103Article in journal (Refereed)
    Abstract [en]

    Most earlier studies of DHTs under churn have either depended on simulations as the primary investigation tool, or on establishing bounds for DHTs to function. In this paper, we present a complete analytical study of churn using a master-equation- based approach, used traditionally in non-equilibrium statistical mechanics to describe steady-state or transient phenomena. Simulations are used to verify all theoretical predictions. We demonstrate the application of our methodology to the Chord system. For any rate of churn and stabilization rates, and any system size, we accurately predict the fraction of failed or incorrect successor and finger pointers and show how we can use these quantities to predict the performance and consistency of lookups under churn. We also discuss briefly how churn may actually be of different 'types' and the implications this will have for the functioning of DHTs in general.

  • 45.
    Kruusmaa, Maarja
    et al.
    Chalmers University of Technology, Department of Computer Engineering, Gothenburg, Sweden.
    Svensson, Bertil
    Halmstad University, School of Information Technology, Halmstad Embedded and Intelligent Systems Research (EIS).
    A low-risk approach to mobile robot path planning1998In: Lecture Notes in Computer Science, ISSN 0302-9743, E-ISSN 1611-3349, Vol. 1416, p. 132-141Article in journal (Refereed)
    Abstract [en]

    This paper presents a self-organizing approach for mobile robot path planning problems in dynamic environments by using case-based reasoning together with a more conventional method of grid-map based path planning. The map-based path planner is used to suggest new innovative solutions for a particular path planning problem. The case-base is used to store the paths and evaluate their traversability. While planning the route those paths are preferred which, according to former experience, are least risky. As the environment changes, the exploration as well as the evaluation of the paths will allow the system to self-organize by forming a set of low-risk paths that are safest to follow. The experiments in a simulated environment show that the robot is able to adapt in a dynamic environment and learns to use the least risky paths. © Springer-Verlag Berlin Heidelberg 1998.

  • 46. Kungas, Peep
    et al.
    Matskin, Mihhail
    KTH, School of Information and Communication Technology (ICT), Communication: Services and Infrastucture (Closed 20120101), Software and Computer Systems, SCS (Closed 20120101).
    Linear logic, partial deduction and cooperative problem solving2004In: Lecture Notes in Computer Science, ISSN 0302-9743, E-ISSN 1611-3349, Vol. 2990, p. 263-279Article in journal (Refereed)
    Abstract [en]

    In this paper we present a model of cooperative problem solving (CPS). Linear Logic (LL) is used for encoding agents' states, goals and capabilities. LL theorem proving is applied by each agent to determine whether the particular agent is capable of solving the problem alone. If no individual solution can be constructed, then the agent may start negotiation with other agents in order to find a cooperative solution. Partial deduction in LL is used to derive a possible deal. Finally proofs are generated and plans are extracted from the proofs. The extracted plans determine agents' responsibilities in cooperative solutions.

  • 47. Kungas, Peep
    et al.
    Rao, J
    Matskin, Mihhail
    KTH, School of Information and Communication Technology (ICT), Communication: Services and Infrastucture (Closed 20120101), Software and Computer Systems, SCS (Closed 20120101).
    Symbolic agent negotiation for semantic web service exploitation2004In: Lecture Notes in Computer Science, ISSN 0302-9743, E-ISSN 1611-3349, Vol. 3129, p. 458-467Article in journal (Refereed)
    Abstract [en]

    This paper presents an architecture and a methodology for agent-based Web service discovery and composition. We assume that Web services are described with declarative specifications like DAML-S. Based on the declarative information about services, symbolic reasoning can be applied while searching for or composing automatically new services. We propose that symbolic agent negotiation could be used for dynamic Web service discovery and composition. Symbolic negotiation, as we consider it here, is a mixture of distributed planning and information exchange. Therefore, by using symbolic negotiation for automated service composition, we support information collection and integration during service composition. The latter aspect has been largely neglected in automated service composition until now.

  • 48.
    Landin, Nils
    et al.
    KTH.
    Romano, Joseph M.
    McMahan, William
    Kuchenbecker, Katherine J.
    Dimensional Reduction of High-Frequency Accelerations for Haptic Rendering2010In: Lecture Notes in Computer Science, ISSN 0302-9743, E-ISSN 1611-3349, Vol. 6192, p. 79-86Article in journal (Refereed)
    Abstract [en]

    Haptics research has seen several recent efforts at understanding and recreating real vibrations to improve the quality of haptic feedback in both virtual environments and teleoperation. To simplify the modeling process and enable the use of single-axis actuators, these previous efforts have used just one axis of a three-dimensional vibration signal, even though the main vibration mechanoreceptors in the hand are know to detect vibrations in all directions. Furthermore, the fact that these mechanoreceptors are largely insensitive to the direction of high-frequency vibrations points to the existence of a transformation that can reduce three-dimensional high-frequency vibration signals to a one-dimensional signal without appreciable perceptual degradation. After formalizing the requirements for this transformation, this paper describes and compares several candidate methods of varying degrees of sophistication, culminating in a novel frequency-domain solution that performs very well on our chosen metrics.

  • 49.
    Larusdottir, Marta Kristín
    KTH, School of Computer Science and Communication (CSC), Human - Computer Interaction, MDI (closed 20111231). Reykjavik University, Iceland .
    Usability evaluation in software development practice2011In: Lecture Notes in Computer Science, ISSN 0302-9743, E-ISSN 1611-3349, Vol. 6943, no PART 4, p. 430-433Article in journal (Refereed)
    Abstract [en]

    Brief description of the topic: Usability evaluation is explored by comparing the effectiveness of using different evaluation methods and by studying how usability evaluation is conducted by practitioners.

  • 50.
    Lundqvist, Henrik
    et al.
    KTH, School of Electrical Engineering (EES), Communication Networks.
    Más Ivars, Ignacio
    KTH, School of Electrical Engineering (EES), Communication Networks.
    Karlsson, Gunnar
    KTH, School of Electrical Engineering (EES), Communication Networks.
    Edge-based Differentiated Services2005In: Lecture Notes in Computer Science, ISSN 0302-9743, E-ISSN 1611-3349, Vol. 3552, p. 259-270Article in journal (Refereed)
    Abstract [en]

    Network quality of service is traditionally thought to be provided by a combination of scheduling in the network nodes to enforce a capacity sharing policy and traffic controls to prevent congestion that could annihilate that policy. The work presented herein is instead based on an end-to-end argument: A capacity sharing policy is enforced by traffic controls in the hosts at the edges of the network, without any scheduling support in the network. Our proposal is to add a feed-forward control at the transport layer to provide a service that is better suited to conversational and streaming applications than the batch-oriented transfer mode provided by TCP. The paper presents the control and its evaluation: We compare the sharing of capacity between traffic classes and study the loss rate seen by admitted streams. The outcome is that the new control adds a distinctly different service to the service offered by TCP for the Internet.

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