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  • 301. Ko, JeongGil
    et al.
    Eriksson, Joakim
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Tsiftes, Nicolas
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Dawson-Haggerty, Stephen
    Terzis, Andreas
    Dunkels, Adam
    RISE, Swedish ICT, SICS.
    Culler, David
    ContikiRPL and TinyRPL: Happy Together2011Conference paper (Refereed)
  • 302. Ko, JeongGil
    et al.
    Eriksson, Joakim
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Tsiftes, Nicolas
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Dawson-Haggerty, Stephen
    Vasseur, Jean-Philippe
    Durvy, Mathilde
    Terzis, Andreas
    Dunkels, Adam
    RISE, Swedish ICT, SICS.
    Culler, David
    Demo: An Interoperability Development and Performance Diagnosis Environment2011Conference paper (Refereed)
    Abstract [en]

    Interoperability is key to widespread adoption of sensor network technology, but interoperable systems have traditionally been difficult to develop and test. We demonstrate an interoperable system development and performance diagnosis environment in which different systems, different software, and different hardware can be simulated in a single network configuration. This allows both development, verification, and performance diagnosis of interoperable systems. Estimating the performance is important since even when systems interoperate, the performance can be sub-optimal, as shown in our companion paper that has been conditionally accepted for SenSys 2011.

  • 303. Ko, JeongGil
    et al.
    Eriksson, Joakim
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Tsiftes, Nicolas
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Dawson-Haggerty, Stephen
    Vasseur, Jean-Philippe
    Durvy, Mathilde
    Terzis, Andreas
    Dunkels, Adam
    RISE, Swedish ICT, SICS.
    Culler, David
    Industry: Beyond Interoperability -- Pushing the Performance of Sensor Network IP Stacks2011Conference paper (Refereed)
  • 304. Ko, JeongGil
    et al.
    Tsiftes, Nicolas
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Dunkels, Adam
    RISE, Swedish ICT, SICS.
    Terzis, Andreas
    Pragmatic Low-Power Interoperability: ContikiMAC vs TinyOS LPL2012Conference paper (Refereed)
    Abstract [en]

    Standardization has driven interoperability at multiple layers of the stack, such as the routing and application layers, standardization of radio duty cycling mechanisms have not yet reached the same maturity. In this work, we pitch the two de facto standard flavors of sender-initiated radio duty cycling mechanisms against each other: ContikiMAC and TinyOS LPL. Our aim is to explore pragmatic interoperability mechanisms at the radio duty cycling layer. This will lead to better understanding of interoperability problems moving forward, as radio duty cycling mechanisms get standardized. Our results show that the two flavors can be configured to operate together but that parameter configuration may severely hurt performance.

  • 305.
    Konovalov, Igor
    et al.
    RISE, Swedish ICT, SICS.
    Neander, Jonas
    Gidlund, Mikael
    Österlind, Fredrik
    RISE, Swedish ICT, SICS.
    Voigt, Thiemo
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Evaluation of WirelessHART Enabled Devices in a Controlled Simulation Environment2011Conference paper (Refereed)
  • 306.
    Kosmack Vaara, Elsa
    et al.
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Höök, Kristina
    RISE, Swedish ICT, SICS.
    Tholander, Jakob
    Mirroring bodily experiences over time2009In: Proceedings of the 27th international conference extended abstracts on Human factors in computing systems, 2009, 6, p. 4471-4476Conference paper (Refereed)
    Abstract [en]

    The Affective Health system is a mobile lifestyle application that aims to empower people to reflect on their lives and lifestyles. The system logs a mixture of biosensor-data and other contextually oriented data and transforms these to a colorful, animated expression on their mobiles. It is intended to create a mirror and thereby empower users to see activity patterns and relate these to their experiences of stress. People's different cultural backgrounds and their different physiological and psychological composition give them different perceptions and associations of time. We explore the time dimension of our system through working through a set of different designs that organize events as time going linearly forward, in a circular movement or relating to geographical places. Here we discuss the process of designing a mobile interface for presenting temporal data in a way that allows multiple and subjective interpretation.

  • 307.
    Kosmack Vaara, Elsa
    et al.
    RISE - Research Institutes of Sweden, ICT, SICS.
    Silvasan, Iuliana
    Ståhl, Anna
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Höök, Kristina
    RISE, Swedish ICT, SICS.
    Temporal Relations in Affective Health2010In: NordiCHI '10 Proceedings of the 6th Nordic Conference on Human-Computer Interaction, 2010, 13Conference paper (Refereed)
    Abstract [en]

    In the Affective Health project we explore possibilities of how to, through biofeedback support users in making sense of the relationship between their stress and their behavior in everyday life. Affective Health is a tool for visualizing patterns and trends of bodily and contextual information. It is particularly important that the design reflects changes over time as this is how people start recognizing patterns in their own behavior and connect it to their bodily reactions. We spent substantial effort sketching and testing ways of portraying time that would move us away from more mathematically inspired representations such as for example graphs and calendars. Instead, we want users to see the signals our bodies emit as part of themselves, of their own ways of being in the world, alive, acting and reacting to their environment. We have explored many possible, alternative ways of visualizing temporal representations through biofeedback. For example as the relation between different places and with time as different layers of history in a concept inspired from ecology. The latest and most developed concept is a cyclic repetition of biodata mapped on a spiral shape.

  • 308. Kovatsch, Matthias
    et al.
    Duquennoy, Simon
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Dunkels, Adam
    RISE, Swedish ICT, SICS.
    A Low-Power CoAP for Contiki2011Conference paper (Refereed)
    Abstract [en]

    Internet of Things devices will by and large be battery-operated, but existing application protocols have typically not been designed with power-efficiency in mind. In low-power wireless systems, power-efficiency is determined by the ability to maintain a low radio duty cycle: keeping the radio off as much as possible. We present an implementation of the IETF Constrained Application Protocol (CoAP) for the Contiki operating system that leverages the ContikiMAC low-power duty cycling mechanism to provide power efficiency. We experimentally evaluate our low-power CoAP, demonstrating that an existing application layer protocol can be made power-efficient through a generic radio duty cycling mechanism. To the best of our knowledge, our CoAP implementation is the first to provide power-efficient operation through radio duty cycling. Our results question the need for specialized low-power mechanisms at the application layer, instead providing low-power operation only at the radio duty cycling layer.

  • 309. Kovatsch, Matthias
    et al.
    Lanter, Martin
    Duquennoy, Simon
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Actinium: A RESTful Runtime Container for Scriptable Internet of Things Applications2012Conference paper (Refereed)
    Abstract [en]

    Programming Internet of Things (IoT) applications is challenging because developers have to be knowledgeable in various technical domains, from low-power networking, over embedded operating systems, to distributed algorithms. Hence, it will be challenging to find enough experts to provide software for the vast number of expected devices, which must also be scalable and particularly safe due to the connection to the physical world. To remedy this situation, we propose an architecture that provides Web-like scripting for low-end devices through Cloud-based application servers and a consistent, RESTful programming model. Our novel runtime container Actinium (Ac) exposes scripts, their configuration, and their lifecycle management through a fully RESTful programming interface using the Constrained Application Protocol (CoAP). We endow the JavaScript language with an API for direct interaction with mote-class IoT devices, the CoapRequest object, and means to export script data as Web resources. With Actinium, applications can be created by simply mashing up resources provided by CoAP servers on devices, other scripts, and classic Web services. We also discuss security considerations and show the suitability of this architecture in terms of performance with our publicly available implementation.

  • 310.
    Kreuger, Per
    et al.
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Carlsson, Mats
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Olsson, Jan
    RISE - Research Institutes of Sweden, ICT, SICS.
    Sjöland, Thomas
    RISE - Research Institutes of Sweden, ICT, SICS.
    Åström, Emil
    RISE - Research Institutes of Sweden, ICT, SICS.
    The TUFF train scheduler1997In: ILPS'97 Workshop on Tools and Environments for (Constraint) Logic Programmins / [ed] G. Puebla, 1997, 1Conference paper (Refereed)
  • 311.
    Kreuger, Per
    et al.
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Carlsson, Mats
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Olsson, Jan
    Sjöland, Thomas
    RISE - Research Institutes of Sweden, ICT, SICS.
    Åström, Emil
    The TUFF train scheduler: two duration trip scheduling on single track networks1997In: CP'97 Workshop on Industrial Constraint-Driven Scheduling / [ed] A. Davenport, 1997, 1, , p. 12Conference paper (Refereed)
  • 312.
    Kreuger, Per
    et al.
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Carlsson, Mats
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Sjöland, Thomas
    RISE - Research Institutes of Sweden, ICT, SICS.
    Åström, Emil
    RISE - Research Institutes of Sweden, ICT, SICS.
    Sequence dependent task extensions for trip scheduling2001Report (Other academic)
    Abstract [en]

    A constraint model for scheduling train trips on a network of tracks used in both directions, using a headway abstraction is described. We argue that a generalisation of a straightforward job-shop scheduling formulation using sequence dependent task extensions can decrease the required resolution of network representation and hence problem size. A geometric interpretation of the model of the constraints that can be used to visualise schedules is presented. Preliminary ideas on search heuristics are presented with performance results and a set of examples.

  • 313.
    Krishnamurthy, Supriya
    et al.
    RISE, Swedish ICT, SICS.
    El-Ansary, Sameh
    RISE, Swedish ICT, SICS.
    Aurell, Erik
    Haridi, Seif
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Comparing maintenance strategies for overlays2007Report (Other academic)
    Abstract [en]

    In this paper, we present an analytical tool for understanding the performance of structured overlay networks under churn based on the master-equation approach of physics. We motivate and derive an equation for the average number of hops taken by lookups during churn, for the Chord network. We analyse this equation in detail to understand the behaviour with and without churn. We then use this understanding to predict how lookups will scale for varying peer population as well as varying the sizes of the routing tables. We also consider a change in the maintenance algorithm of the overlay, from periodic stabilisation to a reactive one which corrects fingers only when a change is detected. We generalise our earlier analysis to understand how the reactive strategy compares with the periodic one.

  • 314.
    Krishnamurthy, Supriya
    et al.
    RISE, Swedish ICT, SICS.
    El-Ansary, Sameh
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Aurell, Erik
    Haridi, Seif
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Comparing Maintenance Strategies for Overlays2008Conference paper (Refereed)
    Abstract [en]

    In this paper, we present an analytical tool for understanding the performance of structured overlay networks under churn based on the master-equation approach of physics. We motivate and derive an equation for the average number of hops taken by lookups during churn, for the Chord network. We analyse this equation in detail to understand the behaviour with and without churn. We then use this understanding to predict how lookups will scale for varying peer population as well as varying the sizes of the routing tables. We also consider a change in the maintenance algorithm of the overlay, from periodic stabilisation to a reactive one which corrects fingers only when a change is detected. We generalise our earlier analysis to understand how the reactive strategy compares with the periodic one.

  • 315.
    Kumm, Mia
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Fire Research.
    Wirström, Niklas
    RISE, Swedish ICT, SICS.
    Nilsson, Martin
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Ingason, Haukur
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Fire Research.
    Vylund, Lotta
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Fire Research.
    Safety positioning for first responders to fires in underground constructions: A pre-study of demands and possibilities2016Report (Other academic)
    Abstract [en]

    This report presents the results of the SafePos pre-study, in which different technologies for safety positioning to be used by first responders were identified, and techniques for ad hoc positioning were evaluated. The aim of the project, was to test various systems for localisation and communication and narrow- and wide-band radio transmission techniques, and to further investigate how the presence of such a system could support fire and rescue operations in complex underground environments. Tests have been carried out in real, pre-existing mining environments, and complex office corridors with similar conditions to those of a mine as regards curves and obstructions have been used for introductory tests. A computer application for digital simulation has been developed and adapted to the system, although this only operates on a relatively basic level, so as to support the testing of the positioning and communication systems; thus, more can be done to improve performance for real-life applications. The analysis was conducted by studying the results of the experiments and linking them to expected usage during a fire and rescue operation. Tests have also been carried out in cooperation with the fire and rescue services in order to identify equipment and wearable technologies that could support and make fire and rescue operations in mines and other complex underground constructions safer and more efficient. In order to transfer information to and from these wearable technologies and to improve the likelihood of a safe and efficient fire and rescue operation, positioning and connectivity are requirements.Keywords: Underground constructions, mine, fire safety, positioning, connectivity

  • 316. La Poutré, Han
    et al.
    Sadeh, Norman M.Janson, SverkerRISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Agent-Mediated Electronic Commerce - Designing Trading Agents and Mechanisms2006Collection (editor) (Refereed)
  • 317.
    Laaksolahti, Jarmo
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Explaining recommendations through user groups2000In: Proceedings of NordiCHI'2000: the First Nordic Conference on Computer Human Interaction, 23-25 Oct 2000, Stockholm, Sweden, 2000, 1Conference paper (Refereed)
  • 318.
    Laaksolahti, Jarmo
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Methods for evaluating a dramatic game2005Conference paper (Refereed)
    Abstract [en]

    This paper describes ongoing work on creating a dramatic gaming prototype. A specific problem is how to evaluate the game and the gaming experience as there are no existing methods specifically suited for this purpose. Two methods are presented that aim to capture different aspects of the players’ subjective experiences. One of the methods, the sensual evaluation instrument, is an experimental non-verbal method that attempts to capture players’ immediate emotional experiences. The other, Repertory Grid Technique, is a method for eliciting and evaluating people’s subjective experience of interacting with technology, used after the gaming session.

  • 319.
    Laaksolahti, Jarmo
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Methods for Evaluating a Dramatic Game: Capturing subjective enjoyment of dramatic experiences2006In: Technology-Mediated Narrative Environments for Learning, Rotterdam/Taipei: Sense Publishers , 2006, 1, p. 123-132Chapter in book (Refereed)
  • 320.
    Laaksolahti, Jarmo
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Plot, Spectacle, and Experience: Contributions to the Design and Evaluation of Interactive Storytelling2008Doctoral thesis, monograph (Other academic)
    Abstract [en]

    Interactive storytelling is a new form of storytelling emerging in the crossroads of many scholarly, artistic, and industrial traditions. In interactive stories the reader/spectator moves from being a receiver of a story to an active participant. By allowing participants to influence the progression and outcome of the story new experiences will arise. This thesis has worked on three aspects of interactive storytelling: plot, spectacle, and experience. The first aspect is concerned with finding methods for combining the linear structure of a story, with the freedom of action required for an interactive experience. Our contribution has focused on a method for avoiding unwanted plot twists by predicting the progression of a story and altering its course if such twists are detected. The second aspect is concerned with supporting the storytelling process at the level of spectacle. In Aristotelian terms, spectacle refers to the sensory display that meets the audience of a drama and is ultimately what causes the experience. Our contribution focuses on graphically making changing emotions and social relations, important elements of dramatic stories in our vision, salient to players at the level of spectacle. As a result we have broadened the view of what is important for interactive storytelling, as well as what makes characters believable. So far not very much research has been done on evaluating interactive stories. Experience, the third aspect, is concerned with finding qualitative methods for evaluating the experience of playing an interactive story. In particular we were interested in finding methods that could tell us something about how a players experience evolved over time, in addition to qualities such as agency that have been claimed to be characteristic for interactive stories. Our contribution consists of two methods that we have developed and adapted for the purposes of evaluating interactive stories that can provide such information. The methods have been evaluated on three different interactive storytelling type games.

  • 321.
    Laaksolahti, Jarmo
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Towards Socio-Emotionally Rich Interactive Narrative2003Licentiate thesis, monograph (Other academic)
  • 322.
    Laaksolahti, Jarmo
    et al.
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Bergmark, Niklas
    Hedlund, Erik
    Enhancing Believability using Affective Cinematography2003In: Intelligent Virtual Agents, 4th International Workshop, IVA 2003, Berlin, Heidelberg: Springer Verlag , 2003, 1Conference paper (Refereed)
  • 323.
    Laaksolahti, Jarmo
    et al.
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Boman, Magnus
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Anticipatory Guidance of Plot2003In: Anticipatory Behavior in Adaptive Learning Systems, Berlin, Heidelberg, New York: Springer Verlag , 2003, 1Chapter in book (Refereed)
  • 324.
    Laaksolahti, Jarmo
    et al.
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Isbister, Katherine
    Höök, Kristina
    RISE, Swedish ICT, SICS.
    Using the sensual evaluation instrument2009Conference paper (Refereed)
    Abstract [en]

    In our research we made use of an instrument previously developed to facilitate nonverbal self-report of emotion, which consists of 8 sculpted objects. We describe the use of this instrument in the assessment of three interactive storytelling experiences in a small user study, and draw some conclusions about the instrument’s effectiveness in supporting design.

  • 325.
    Laaksolahti, Jarmo
    et al.
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Isbister, Katherine
    Höök, Kristina
    RISE, Swedish ICT, SICS.
    Using the Sensual Evaluation Instrument2009In: Journal of Digital Creativity, Vol. 3, p. 165-175Article in journal (Refereed)
    Abstract [en]

    In our research we made use of an instrument previously developed to facilitate nonverbal self-report of emotion, which consists of eight sculpted objects. We describe the use of this instrument in the assessment of three interactive storytelling experiences in a small user study and draw some conclusions about the instrument's effectiveness in supporting design.

  • 326.
    Laaksolahti, Jarmo
    et al.
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Persson, Per
    Palo, Carolina
    Evaluating Believability in an Interactive Narrative2001In: Intelligent Agent Technology - Research and Development, New Jersey, London, Singapore, Hong Kong: World Scientific , 2001, 1Conference paper (Refereed)
  • 327.
    Laaksolahti, Jarmo
    et al.
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Tholander, Jakob
    Lundén, Marcus
    RISE, Swedish ICT, SICS.
    Solsona Belenguer, Jordi
    Karlsson, Anna
    Jaensson, Tove
    The LEGA: a device for leaving and finding tactile traces2011Conference paper (Refereed)
    Abstract [en]

    This paper describes experiences from development and deployment of the Lega, a hand held device for physical sharing of experiences during an art exhibition. Touching and moving the device in different ways creates a tactile trace that can be experienced by others through their own device. The system was successfully deployed at an art exhibition for two months where user studies were performed. Here we present some general observations regarding the systems performance and discuss issues that we encountered.

  • 328.
    Laaksolahti, Jarmo
    et al.
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Waern, Annika
    RISE - Research Institutes of Sweden, ICT, SICS.
    Talking to the Swedish chef: social interactions in recommender systems1999In: Proceedings of the 13th workshop on Behavior Planning for Life-Like Characters and Avatars, March 1999, Sitges, Spain, 1999, 1Conference paper (Refereed)
  • 329. Landin, Anders
    et al.
    Hagersten, Erik
    Haridi, Seif
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Race-free interconnection networks and multiprocessor consistency1991Conference paper (Refereed)
  • 330.
    Landin, Anders
    et al.
    RISE, Swedish ICT, SICS.
    Haridi, Seif
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Hagersten, Erik
    RISE, Swedish ICT, SICS.
    DDM - a cache-only memory architecture1991Report (Other academic)
    Abstract [en]

    The long latencies introduced by remote accesses in a large multiprocessor can be hidden by caching. Caching also decreases the network load. We introduce a new class of architectures called Cache Only Memory Archi-tectures (COMA). These architectures provide the programming paradigm of the shared-memory architectures, but have no physically shared memory; instead, the caches attached to the processors containallthe memory in the system, and their size is therefore large. A datum is allowed to be in any or many of the caches, and will automatically be moved to where it is needed by a cache-coherence protocol,which also ensures that the last copy of a datum is never lost. The location of a datum in the machine is completely decoupled from its address. We also introduce one example of COMA: the Data Diffusion Machine (DDM), and its simulated performance for large applications. The DDM is based on a hierarchical network structure, with processor/memory pairs at its tips. Remote accesses generally cause only a limited amount of traffic over a limited part of the machine.

  • 331.
    Landin, Anders
    et al.
    RISE, Swedish ICT, SICS.
    Haridi, Seif
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Hagersten, Erik
    RISE, Swedish ICT, SICS.
    Moving the shared memory closer to the processors: DDM1990Report (Refereed)
    Abstract [en]

    Multiprocessors with shared memory are considered more general and easier to program than message-passing machines. The scalability is, however, in favor of the latter. There are a number of proposals showing how the poor scalability of shared memory multiprocessors can be improved by the introduction of private caches attached to the processors. These caches are kept consistent with each other by cache-coherence protocols. In this paper we introduce a new class of architectures called Cache Only Memory Architectures (COMA). These architectures provide the programming paradigm of the shared-memory architectures, but are believed to be more scal- able. COMAs have no physically shared memory; instead, the caches attached to the processors contain all the memory in the system, and their size is therefore large. A datum is allowed to be in any or many of the caches, and will automatically be moved to where it is needed by a cache-coherence protocol, which also ensures that the last copy of a datum is never lost. The location of a datum in the machine is completely decoupled from its address. We also introduce one example of COMA: the Data Diffusion Machine (DDM). The DDM is based on a hierarchical network structure, with processor/memory pairs at its tips. Remote accesses generally cause only a limited amount of traffic over a limited part of the machine. The architecture is scalable in that there can be any number of levels in the hierarchy, and that the root bus of the hierarchy can be implemented by several buses, increasing the bandwidth.

  • 332.
    Landin, Anders
    et al.
    RISE, Swedish ICT, SICS.
    Haridi, Seif
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Hagersten, Erik
    RISE, Swedish ICT, SICS.
    Andersson, Pär
    A performance study of the DDM - a cache-only memory architecture1991Report (Refereed)
    Abstract [en]

    Large-scale multiprocessors suffer from long latencies for remote accesses. Caching is by far the most popular technique for hiding such delays. Caching not only hides the delay, but also decreases the network load. Cache-Only Memory Architectures (COMA), have no physically shared memory. Instead, all the memory resources are invested in caches, resulting in caches of the largest possible size. A datum has no home, and is moved by a protocol between the caches, according to its usage. It might exist in multiple caches. Even though no shared memory exists, the architecture still provides the shared memory view to a programmer. Simulation results from large programs running on 64 processors indicate that the COMA adapts well to existing programs for shared memory. They also show that an application with a poor locality can benefit by adopting to the COMA principle of no home for data, resulting in a reduced execution time of a factor three. In a COMA, a large majority of the misses are invalidation misses, or share misses caused by write-once/read-many behavior, or a producer-consumer relation, i.e. would ben- efit from write broadcast. A new protocol is proposed that behaves like a write-invalidate protocol by default for all data. A reader can detect its need for a write-broadcast behavior for a datum, which it enables by sending a subscribe request for the datum to the writer.

  • 333. Landsiedel, Olaf
    et al.
    Ghadimi, Euhanna
    Duquennoy, Simon
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Johansson, Mikael
    Low Power, Low Delay: Opportunistic Routing meets Duty Cycling2012Conference paper (Refereed)
    Abstract [en]

    Traditionally, routing in wireless sensor networks consists of two steps: First, the routing protocol selects a next hop, and, second, the MAC protocol waits for the intended destination to wake up and receive the data. This design makes it difficult to adapt to link dynamics and introduces delays while waiting for the next hop to wake up. In this paper we introduce ORW, a practical opportunistic routing scheme for wireless sensor networks. In a dutycycled setting, packets are addressed to sets of potential receivers and forwarded by the neighbor that wakes up first and successfully receives the packet. This reduces delay and energy consumption by utilizing all neighbors as potential forwarders. Furthermore, this increases resilience to wireless link dynamics by exploiting spatial diversity. Our results show that ORW reduces radio duty-cycles on average by 50% (up to 90% on individual nodes) and delays by 30% to 90% when compared to the state of the art.

  • 334.
    Larson, Jeffrey
    et al.
    KTH Royal Institute of Technology, Sweden; Argonne National Laboratory, USA.
    Johansson, Mikael
    KTH Royal Institute of Technology, Sweden.
    Carlsson, Mats
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    An Integrated Constraint Programming Approach to Scheduling Sports Leagues with Divisional and Round-Robin Tournaments2014Conference paper (Refereed)
    Abstract [en]

    Previous approaches for scheduling a league with round-robin and divisional tournaments involved decomposing the problem into easier subproblems. This approach, used to schedule the top Swedish handball league Elitserien, reduces the problem complexity but can result in suboptimal schedules. This paper presents an integrated constraint programming model that allows to perform the scheduling in a single step. Particular attention is given to identifying implied and symmetry-breaking constraints that reduce the computational complexity significantly. The experimental evaluation of the integrated approach takes considerably less computational effort than the previous approach.

  • 335. Letort, Arnaud
    et al.
    Beldiceanu, Nicolas
    Carlsson, Mats
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    A Scalable Sweep Algorithm for the "cumulative" Constraint2012Conference paper (Refereed)
    Abstract [en]

    This paper presents a sweep based algorithm for the cumulative constraint, which can operate in filtering mode as well as in greedy assignment mode. Given n tasks, this algorithm has a worst-case time complexity of O(n 2). In practice, we use a variant with better average-case complexity but worst-case complexity of O(n 2 log n), which goes down to O(n log n) when all tasks have unit duration, i.e. in the bin-packing case. Despite its worst-case time complexity, this algorithm scales well in practice, even when a significant number of tasks can be scheduled in parallel. It handles up to 1 million tasks in one single cumulative constraint in both Choco and SICStus.

  • 336. Letort, Arnaud
    et al.
    Carlsson, Mats
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Beldiceanu, Nicolas
    A Synchronized Sweep Algorithm for the k-Dimensional Cumulative Constraint2013In: CPAIOR, Springer , 2013, 9, Vol. LNCS 7874, p. 144-159Conference paper (Refereed)
    Abstract [en]

    This paper presents a sweep based algorithm for the k-dimensional Cumulative constraint, which can operate in filtering mode as well as in greedy assignment mode. Given n tasks and k resources, this algorithm has a worst-case time complexity of O(kn^2) but scales well in practice. In greedy assignment mode, it handles up to 1 million tasks with 64 resources in one single constraint in SICStus. In filtering mode, on our benchmarks, it yields a speed-up of about k^(3/4) when compared to its decomposition into k independent Cumulative constraints.

  • 337. Letort, Arnaud
    et al.
    Carlsson, Mats
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Beldiceanu, Nicolas
    Synchronized sweep algorithms for scalable scheduling constraints2013Report (Other academic)
    Abstract [en]

    This report introduces a family of synchronized sweep based filtering algorithms for handling scheduling problems involving resource and precedence constraints. The key idea is to filter all constraints of a scheduling problem in a synchronized way in order to scale better. In addition to normal filtering mode, the algorithms can run in greedy mode, in which case they perform a greedy assignment of start and end times. The filtering mode achieves a significant speed-up over the decomposition into independent cumulative and precedence constraints, while the greedy mode can handle up to 1 million tasks with 64 resources constraints and 2 million precedences. These algorithms were implemented in both CHOCO and SICStus.

  • 338. Letort, Arnaud
    et al.
    Carlsson, Mats
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Beldiceanu, Nicolas
    Synchronized sweep algorithms for scalable scheduling constraints2014In: Constraints, ISSN 1383-7133, E-ISSN 1572-9354, Vol. 19, p. 1-52Article in journal (Refereed)
    Abstract [en]

    This paper introduces a family of synchronized sweep-based filtering algorithms for handling scheduling problems involving resource and precedence constraints. The key idea is to filter all constraints of a scheduling problem in a synchronized way in order to scale better. In addition to normal filtering mode, the algorithms can run in greedy mode, in which case they perform a greedy assignment of start and end times. The filtering mode achieves a significant speed-up over the decomposition into independent CUMULATIVE and precedence constraints, while the greedy mode can handle up to 1 million tasks with 64 resource constraints and 2 million precedences. These algorithms were implemented in both CHOCO and SICStus.

  • 339.
    Li, Qian
    et al.
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Österlind, Fredrik
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Voigt, Thiemo
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Fischer, Stefan
    Pfisterer, Dennis
    Making Wireless Sensor Network Simulators Cooperate2010Conference paper (Refereed)
  • 340.
    Li, Yafei
    et al.
    RISE, Swedish ICT, SICS.
    He, Zhitao
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Voigt, Thiemo
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Leidelöf, Sanna
    A software radio-empowered sensor network2009In: 9th Scandinavian Workshop on Wireless Adhoc Networks (Adhoc'09), 2009, 1Conference paper (Refereed)
    Abstract [en]

    Low power wireless sensors are limited by current radio technologies to short communication range and low throughput. We envision that future radios with advanced software programmable encoding and modulation will bring sensor networks unprecedented flexibility and performance. We have taken a step towards realizing this vision by designing a softwarebased, narrow-band transceiver using the GNU Radio software and the Universal Software Radio Peripheral hardware. We have verified the compatibility of our implementation with existing wireless sensor platforms. We demonstrate the flexibility of our design with sensing applications running on a sensor network communicating over hybrid radios.

  • 341. Lindström, Madlene
    et al.
    Ståhl, Anna
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Höök, Kristina
    RISE, Swedish ICT, SICS.
    Sundström, Petra
    RISE - Research Institutes of Sweden, ICT, SICS.
    Laaksolahti, Jarmo
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Combetto, Marco
    Taylor, Alex
    Breslin, Roberto
    Affective Diary - Designing for Bodily Expressiveness and Self-Reflection2006Conference paper (Refereed)
    Abstract [en]

    A diary provides a useful means to express inner thoughts and record experiences of past events. In re-readings, it also provides a resource for reflection, allowing us to re-experience, brood over or even shed the thoughts and feelings we've associated with events or people. To expand on the ways in which we creatively engage in diary-keeping, we have designed an affective diary that captures some of the physical, bodily aspects of experiences and emotions--what we refer to as "affective body memorabilia". The affective diary assembles sensor data, captured from the user and uploaded via their mobile phone, to form an ambiguous, abstract colourful body shape. With a range of other materials from the mobile phone, such as text and MMS messages, photographs, etc., these shapes are made available to the user. Combining these materials, the diary is designed to invite reflection and to allow the user to piece together their own stories.

  • 342. Linnarsson, Sten
    et al.
    Lönnerberg, Peter
    Olden, Mats
    Aurell, Erik
    Carlsson, Mats
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Ekman, Jan
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Kreuger, Per
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Rasmusson, Lars
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    METHODS FOR PROFILING MOLECULES WITH AN OBJECTIVE FUNCTION2003Patent (Other (popular science, discussion, etc.))
    Abstract [en]

    Methods relating to profiling and/or identifying molecules in a sample, particularly chemical or biological molecules contained in an experimental sample using measured data about molecules actually present and known information about candidate molecules that may be present. Information tags can be assigned to candidates. This may be achieved with a high degree of accuracy and a low false positive rate by minimising the effect of one or more possible sources of error. An objective goal (assignment) may be optimised by linear programming or by mixed integer programming

  • 343.
    Ljungblad, Sara
    et al.
    RISE, Swedish ICT, SICS.
    Kotrbova, Jirina
    Jacobsson, Mattias
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Cramer, Henriette
    Niechwiadowicz, Karol
    Hospital robot at work: something alien or an intelligent colleague?2012Conference paper (Refereed)
  • 344. Lusk, E.
    et al.
    Butler, R.
    Disz, T.
    Overbeek, R.
    Stevens, R.
    Warren, David H.D.
    Calderwood, A.
    Szeredi, Peter
    Brand, Per
    RISE - Research Institutes of Sweden, ICT, SICS.
    Carlsson, Mats
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Ciepielewski, Andrzej
    RISE - Research Institutes of Sweden, ICT, SICS.
    Hausman, Bogumil
    RISE - Research Institutes of Sweden, ICT, SICS.
    Haridi, Seif
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    The Aurora or-parallel Prolog system1990In: New generation computing, ISSN 0288-3635, E-ISSN 1882-7055, Vol. 7, no 2,3, p. 243-271Article in journal (Refereed)
  • 345. Lusk, Ewing
    et al.
    Warren, David H.D.
    Haridi, Seif
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    The Aurora Or-Parallel Prolog system1989Report (Other academic)
    Abstract [en]

    Aurora is a prototype or-parallel implementation of the full Prolog language for shared-memory multiprocessors, developed as part of an informal research collaboration known as the "Gigalips Project". It currently runs on Sequent and Encore machines. It has been constructed by adapting Sicstus Prolog, a fast, portable, sequential Prolog system. The techniques for constructing a portable multiprocessor version follow those pioneered in a predecessor system, ANL-WAM. The SRI model was adopted as the means to extend the Sicstus Prolog engine for or-parallel operation. We describe the design and main implementation features of the current Aurora system, and present some experimental results. For a range of benchmarks, Aurora on a 20-processor Sequent Symmetry is 4 to 7 times faster than Quintus Prolog on a Sun 3/75. Good performance is also reported on some large-scale Prolog applications.

  • 346.
    Löscher, Andreas
    et al.
    Uppsala University, Sweden.
    Sagonas, Konstantinos
    Uppsala University, Sweden.
    Voigt, Thiemo
    RISE, Swedish ICT, SICS, Computer Systems Laboratory. Uppsala University, Sweden.
    Property-Based Testing of Sensor Networks2015In: 2015 12th Annual IEEE International Conference on Sensing, Communication, and Networking (SECON), 2015, 9, p. 100-108, article id 7338296Conference paper (Refereed)
    Abstract [en]

    We advocate the use of property-based testing in the area of sensor networks and present a framework to apply this testing methodology. Our framework provides an expressive high-level language to specify a wide range of properties, starting from properties of individual functions to network-global properties, and infrastructure to automatically test these properties in Cooja, the network simulator of the Contiki operating system. We demonstrate the ease of use and effectiveness of our framework by two case studies. In the first, we test whether the energy consumption of the radio duty-cycle protocol X-MAC is within some specific bound. Property-based testing finds minimal network configurations where a small number of nodes violate the property. Property-based testing also reveals that the same property is not violated when ContikiMAC is used instead, but finds cases where ContikiMAC has higher energy consumption than X-MAC. In the second case study, we test the C API of CONTIKI's TCP socket library and find bugs in its event system that would be very hard to detect with other methods.

  • 347. Löscher, Andreas
    et al.
    Tsiftes, Nicolas
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Voigt, Thiemo
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Handziski, Vlado
    Demo Abstract: Network-Wide Sensornet Checkpointing Made Practical2013Conference paper (Refereed)
  • 348.
    Löscher, Andreas
    et al.
    Uppsala University, Sweden.
    Tsiftes, Nicolas
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Voigt, Thiemo
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Handziski, Vlado
    Technische Universität Berlin, Germany.
    Efficient and Flexible Sensornet Checkpointing2014Conference paper (Refereed)
    Abstract [en]

    Developing sensornet software is difficult partly because of the limited visibility of the system state of deployed nodes. Sensornet checkpointing is a method that allows developers to save and restore full system state of nodes. We present four extensions to sensornet checkpointing - compression, binary diffs, selective checkpointing, and checkpoint inspection - that reduce the time required for checkpointing operations considerably, and improve the granularity at which system state can be examined and manipulated down to the variable level. We show through an experimental evaluation that the checkpoint sizes can be reduced by 70%-93%, and the time can be reduced by at least 50% because of these improvements. The reduced time and increased granularity benefits multiple checkpointing use cases, including automated testing, network visualization, and software debugging.

  • 349.
    Mallach, Sven
    et al.
    Universität zu Köln, Germany.
    Castaneda Lozano, Roberto
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Optimal General Offset Assignment2014Conference paper (Refereed)
    Abstract [en]

    We present an exact approach to the General Offset Assignment problem arising in the domain of address code generation for application specific and digital signal processors. General Offset Assignment is composed of two subproblems, namely to find a permutation of variables in memory and to select a responsible address register for each access to one of these variables. Our method is a combination of established techniques to solve both subproblems using integer linear programming. To the best of our knowledge, it is the first approach capable of solving almost all instances of the established OffsetStone benchmark set to global optimality within reasonable time. We provide a first comprehensive evaluation of the quality of several state-of-the-art heuristics relative to the optimal solutions.

  • 350. Marqués, Antonio
    et al.
    Serrano, Manuel
    Karnouskos, Stamatis
    Marrón, Pedro José
    Sauter, Robert
    Bekiaris, Evangelos
    Kesidou, Eleni
    Höglund, Joel
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    NOBEL - A Neighborhood Oriented Brokerage ELectricity and Monitoring System2011In: Energy-Efficient Computing and Networking, Vol. 54, p. 187-196Article in journal (Refereed)
    Abstract [en]

    Distributed generation of energy coming from various vendors, even private homes, is a big challenge for tomorrows power management systems that, unlike today, will not dispatch energy centrally or under central control. On the contrary, the production, distribution and management of energy will be treated and optimized in a distributed manner using local data. Even today, parts of the power system are highly nonlinear with fast changing dynamics. It is hard to predict disturbances and undertake countermeasures on time. In existing approaches electricity is distributed to the final users according to its expected estimated demand. Such non-dynamic approaches, are difficult to evolve and can not accommodate rapid changes in the system. By having a cross-layer and open information flow among the different actors involved we can make better and more timely predictions, and inject new dynamics in the system that will lead to better energy management and achieve better energy savings. The NOBEL project is building an energy brokerage system with which individual energy prosumers can communicate their energy needs directly to both large-scale and small-scale energy producers, thereby making energy use more efficient.

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