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  • 1. Aberer, Karl
    et al.
    Onana Alima, Luc
    RISE, Swedish ICT, SICS.
    Ghodsi, Ali
    RISE, Swedish ICT, SICS.
    Girdzijauskas, Sarunas
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Hauswirth, Manfred
    Haridi, Seif
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    The essence of P2P: A reference architecture for overlay networks2005Conference paper (Refereed)
    Abstract [en]

    The success of the P2P idea has created a huge diversity of approaches, among which overlay networks, for example, Gnutella, Kazaa, Chord, Pastry, Tapestry, P-Grid, or DKS, have received specific attention from both developers and researchers. A wide variety of algorithms, data structures, and architectures have been proposed. The terminologies and abstractions used, however, have become quite inconsistent since the P2P paradigm has attracted people from many different communities, e.g., networking, databases, distributed systems, graph theory, complexity theory, biology, etc. In this paper we propose a reference model for overlay networks which is capable of modeling different approaches in this domain in a generic manner. It is intended to allow researchers and users to assess the properties of concrete systems, to establish a common vocabulary for scientific discussion, to facilitate the qualitative comparison of the systems, and to serve as the basis for defining a standardized API to make overlay networks interoperable.

  • 2.
    Al Nahas, Beshr
    et al.
    RISE, Swedish ICT, SICS.
    Duquennoy, Simon
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Iyer, Venkatraman
    Voigt, Thiemo
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Low-Power Listening Goes Multi-Channel2014Conference paper (Refereed)
    Abstract [en]

    Exploiting multiple radio channels for communication has been long known as a practical way to mitigate interference in wireless settings. In Wireless Sensor Networks, however, multi-channel solutions have not reached their full potential: the MAC layers included in TinyOS or the Contiki OS for example are mostly single-channel. The literature offers a number of interesting solutions, but experimental results were often too few to build confidence. We propose a practical extension of low-power listening, MiCMAC, that performs channel hopping, operates in a distributed way, and is independent of upper layers of the protocol stack. The above properties make it easy to deploy in a variety of scenarios, without any extra configuration/scheduling/channel selection hassle. We implement our solution in Contiki and evaluate it in a 97-node testbed while running a complete, out-of-the-box low-power IPv6 communication stack (UDP/RPL/6LoWPAN). Our experimental results demonstrate increased resilience to emulated WiFi interference (e.g., data yield kept above 90% when ContikiMAC drops in the 40% range). In noiseless environments, MiCMAC keeps the overhead low in comparison to ContikiMAC, achieving performance as high as 99% data yield along with sub-percent duty cycle and sub-second latency for a 1-minute inter-packet interval data collection.

  • 3.
    Ali, Khayri Mohammed
    et al.
    RISE - Research Institutes of Sweden, ICT, SICS.
    Haridi, Seif
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Global garbage collection for distributed heap storage systems1987Report (Other academic)
    Abstract [en]

    We present a garbage-collection algorithm, suitable for loosely-coupled multiprocessor systems, in which the processing elements (PE's) share only the communication medium. The algorithm is global, i.e. it involves all the PE's in the system. It allows space compaction, and it uses a system-wide marking phase to mark all accessible objects where a combination of parallel breadth-first/depth-first strategies is used for tracing the object-graphs according to a decentralized credit mechanism that regulates the number of garbage collection messages in the system. The credit mechanism is crucial for determining the space requirement of the garbage-collection messages. Also a variation of the above algorithm is presented for systems with high locality of reference. It allows each PE to perform first its local garbage collection and only invokes the global garbage collection when the freed space by the local collector is insufficient.

  • 4.
    Ali, Muneeb
    et al.
    RISE, Swedish ICT, SICS.
    Umar, Saif
    Dunkels, Adam
    RISE, Swedish ICT, SICS.
    Voigt, Thiemo
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Römer, Kay
    Langendoen, Koen
    Polastre, Joseph
    Uzmi, Zartash Afzal
    Medium access control issues in sensor networks2006In: Computer communication review, ISSN 0146-4833, E-ISSN 1943-5819, Vol. 36, p. 33-36Article in journal (Refereed)
    Abstract [en]

    Medium access control for wireless sensor networks has been a very active research area for the past couple of years. The sensor networks literature presents an alphabet soup of medium access control protocols with almost all of the works focusing only on energy efficiency. There is much more innovative work to be done at the MAC layer, but current efforts are not addressing the hard unsolved problems. Majority of the works appearing in the literature are "least publishable incremental improvements" over the popular S-MAC [1] protocol. In this paper we present research directions for future medium access research. We identify some open issues and discuss possible solutions.

  • 5.
    Ali, Muneeb
    et al.
    RISE, Swedish ICT, SICS.
    Voigt, Thiemo
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Uzmi, Zartash Afzal
    Mobility Management in Sensor Networks2006Conference paper (Refereed)
  • 6. Alima, Luc Onana
    et al.
    Haridi, Seif
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Van Roy, Peter
    NetProber: a component for enhancing efficiency of overlay networks in P2P systems2002Conference paper (Refereed)
  • 7. Almgren, Jonas
    et al.
    Andersson, Stefan
    Carlsson, Mats
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Flood, Lena
    Haridi, Seif
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Frisk, Claes
    Nilsson, Hans
    Sundberg, Jan
    SICStus Prolog library manual, version 2.1 #81993Report (Other academic)
    Abstract [en]

    This Manual corresponds to SICStus Prolog release 2.1. #8 The Prolog library comprises a number of packages which are thought to be useful in a number of applications. Note that the predicates in the Prolog library are built-in predicates. One has to explicity load each package to get access to its predicates. To load a library package Package, you will normally enter a query. I ?- use_module(library(Package)). Library packages may be compiled and consulted as well as loaded.

  • 8.
    Alonso, Juan
    et al.
    RISE, Swedish ICT, SICS.
    Dunkels, Adam
    RISE, Swedish ICT, SICS.
    Voigt, Thiemo
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Bounds on the energy consumption of routings in wireless sensor networks2004Conference paper (Refereed)
  • 9.
    Alonso, Juan
    et al.
    RISE - Research Institutes of Sweden, ICT, SICS.
    Dunkels, Adam
    RISE, Swedish ICT, SICS.
    Voigt, Thiemo
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Bounds on the Energy Consumption of Routings in Wireless Sensor Networks2003Report (Other academic)
    Abstract [en]

    Energy is one of the most important resources in wireless sensor networks. We use an idealized mathematical model to study the impact of routing on energy consumption. Our results are very general and, within the assumptions listed in Section 2, apply to arbitrary topologies, routings and radio energy models. We find bounds on the minimal and maximal energy routings will consume, and use them to bound the lifetime of the network. The bounds are sharp, and can be achieved in many situations of interest. We illustrate the theory with some examples.

  • 10. Alonso, Juan
    et al.
    Dunkels, Adam
    RISE, Swedish ICT, SICS.
    Voigt, Thiemo
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Bounds on the Lifetime of Wireless Sensor Networks2004Report (Other academic)
    Abstract [en]

    Energy is one of the most important resources in wireless sensor networks. We use an idealized mathematical model to study the energy consumption under all possible routings. Our results are very general and, within the assumptions listed in Section 2, apply to arbitrary topologies, routings and radio energy models. We find bounds on the minimal and maximal energy routings will consume, and use them to bound the lifetime of the network. The bounds are sharp, and we show that they are achievable in many situations of interest. We give some examples, and apply the theory to the problem of covering a given square region with the most efficient member of a family of increasingly more dense square-lattice sensor networks. Finally, we use simulations to test these results in a more realistic scenario, where packet loss can occur.

  • 11. Alonso, Juan
    et al.
    Voigt, Thiemo
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Varshney, Ambuj
    Bounds on the Lifetime of WSNs2013Conference paper (Refereed)
  • 12.
    Al-Shishtawy, Ahmad
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Self-management for large-scale distributed systems2012Doctoral thesis, monograph (Other academic)
    Abstract [en]

    Autonomic computing aims at making computing systems self-managing by using autonomic managers in order to reduce obstacles caused by management complexity. This thesis presents results of research on self-management for large-scale distributed systems. This research was motivated by the increasing complexity of computing systems and their management. In the first part, we present our platform, called Niche, for programming self-managing component-based distributed applications. In our work on Niche, we have faced and addressed the following four challenges in achieving self-management in a dynamic environment characterized by volatile resources and high churn: resource discovery, robust and efficient sensing and actuation, management bottleneck, and scale. We present results of our research on addressing the above challenges. Niche implements the autonomic computing architecture, proposed by IBM, in a fully decentralized way. Niche supports a network-transparent view of the system architecture simplifying the design of distributed self-management. Niche provides a concise and expressive API for self-management. The implementation of the platform relies on the scalability and robustness of structured overlay networks. We proceed by presenting a methodology for designing the management part of a distributed self-managing application. We define design steps that include partitioning of management functions and orchestration of multiple autonomic managers. In the second part, we discuss robustness of management and data consistency, which are necessary in a distributed system. Dealing with the effect of churn on management increases the complexity of the management logic and thus makes its development time consuming and error prone. We propose the abstraction of Robust Management Elements, which are able to heal themselves under continuous churn. Our approach is based on replicating a management element using finite state machine replication with a reconfigurable replica set. Our algorithm automates the reconfiguration (migration) of the replica set in order to tolerate continuous churn. For data consistency, we propose a majority-based distributed key-value store supporting multiple consistency levels that is based on a peer-to-peer network. The store enables the tradeoff between high availability and data consistency. Using majority allows avoiding potential drawbacks of a master-based consistency control, namely, a single-point of failure and a potential performance bottleneck. In the third part, we investigate self-management for Cloud-based storage systems with the focus on elasticity control using elements of control theory and machine learning. We have conducted research on a number of different designs of an elasticity controller, including a State-Space feedback controller and a controller that combines feedback and feedforward control. We describe our experience in designing an elasticity controller for a Cloud-based key-value store using state-space model that enables to trade-off performance for cost. We describe the steps in designing an elasticity controller. We continue by presenting the design and evaluation of ElastMan, an elasticity controller for Cloud-based elastic key-value stores that combines feedforward and feedback control.

  • 13.
    Al-Shishtawy, Ahmad
    et al.
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Asif Fayyaz, Muhammad
    Popov, Konstantin
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Vlassov, Vladimir
    Achieving Robust Self-Management for Large-Scale Distributed Applications2010Report (Other academic)
    Abstract [en]

    Autonomic managers are the main architectural building blocks for constructing self-management capabilities of computing systems and applications. One of the major challenges in developing self-managing applications is robustness of management elements which form autonomic managers. We believe that transparent handling of the effects of resource churn (joins/leaves/failures) on management should be an essential feature of a platform for self-managing large-scale dynamic distributed applications, because it facilitates the development of robust autonomic managers and hence improves robustness of self-managing applications. This feature can be achieved by providing a robust management element abstraction that hides churn from the programmer. In this paper, we present a generic approach to achieve robust services that is based on finite state machine replication with dynamic reconfiguration of replica sets. We contribute a decentralized algorithm that maintains the set of nodes hosting service replicas in the presence of churn. We use this approach to implement robust management elements as robust services that can operate despite of churn. Our proposed decentralized algorithm uses peer-to-peer replica placement schemes to automate replicated state machine migration in order to tolerate churn. Our algorithm exploits lookup and failure detection facilities of a structured overlay network for managing the set of active replicas. Using the proposed approach, we can achieve a long running and highly available service, without human intervention, in the presence of resource churn. In order to validate and evaluate our approach, we have implemented a prototype that includes the proposed algorithm.

  • 14. Ameur, Adam
    et al.
    Aurell, Erik
    Carlsson, Mats
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Westholm, Jakub Orzechowski
    Global gene expression analysis by combinatorial optimization2004In: In Silico Biology, ISSN 1434-3207, Vol. 4Article in journal (Refereed)
    Abstract [en]

    Generally, there is a trade-off between methods of gene expression analysis that are precise but labor-intensive, e.g. RT-PCR, and methods that scale up to global coverage but are not quite as quantitative, e.g. microarrays. In the present paper, we show how how a known method of gene expression profiling (K. Kato, Nucleic Acids Research 23, 3685-3690 (1995)), which relies on a fairly small number of steps, can be turned into a global gene expression measurement by advanced data post-processing, with potentially little loss of accuracy. Post-processing here entails solving an ancillary combinatorial optimization problem. Validation is performed on in silico experiments generated from the FANTOM data base of full-length mouse cDNA. We present two variants of the method. One uses state-of-the-art commercial software for solving problems of this kind, the other a code developed by us specifically for this purpose, released in the public domain under GPL license.

  • 15. Andersson, Gerd
    et al.
    Bullock, Adrian
    RISE - Research Institutes of Sweden, ICT, SICS.
    Laaksolahti, Jarmo
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Nylander, Stina
    RISE, Swedish ICT, SICS, Software and Systems Engineering Laboratory.
    Olsson, Fredrik
    RISE - Research Institutes of Sweden, ICT, SICS.
    Sjölinder, Marie
    RISE, Swedish ICT, SICS.
    Waern, Annika
    RISE, Swedish ICT, SICS.
    Boman, Magnus
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Classifying Mobile Services2004Report (Other academic)
    Abstract [en]

    A categorization of telecommunications services is presented, as a deliverable in a project commissioned by TeliaSonera.

  • 16. Andersson, Johan
    et al.
    Andersson, Stefan
    Boortz, Kent
    Carlsson, Mats
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Nilsson, Hans
    Sjöland, Thomas
    RISE - Research Institutes of Sweden, ICT, SICS.
    Widén, Johan
    RISE - Research Institutes of Sweden, ICT, SICS.
    SICStus Prolog user's manual, version 2.1 #81993Report (Other academic)
    Abstract [en]

    This Manual corresponds to SICStus Prolog release 2.1. #8 Prolog is a simple but powerful programming language developed at the University of Marseilles (Prolog : Manuel de Reference et d'Utilisation by P.Roussel, Groupe d'Intelligence Artificielle, Marseille-Luminy, 1975), as a practical tool for programming in Logic (Logic for Problem Solving by R.A. Kowalski, DCL Memo 75, Dept. of Artificial Intelligence, University of Edinburgh, March, 1974.)) From a user's point of view the major attraction of the language is ease of programming. Clear, readable, concise programs can be written quickly with few errors. This manual describes a Prolog system developed at the Swedish Institute of Computer Science in collaboration with Ericsson Telecom AB, NobelTech Systems AB, Infologics AB and Televerket under the IT4 program. The system consists of a WAM emulator written in C, a library and runtime system written in C and Prolog and an interpreter and a compiler written in Prolog. The Prolog engine is a Warren Abstract Machine (WAM) emulator defined by D:H:D: Warren in An Abstract Prolog Instruction Set, Tech. Note 309, International, Menlo Park, CA, 1983. Two modes of compilation are available: in-core i.e. incremental, and file-to-file.

  • 17. Appleby, Karen
    et al.
    Carlsson, Mats
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Haridi, Seif
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Sahlin, Dan
    RISE, Swedish ICT, SICS.
    Garbage Collection for Prolog Based on WAM (Revised version)1986Report (Other academic)
    Abstract [en]

    Warren Abstract Machine (WAM) has become a generally accepted standard Prolog implementation technique. Garbage collection is an important aspect in the implementation of any Prolog system. We first present a synopsis of the WAM and then show marking and compaction algorithms that take advantage of WAM's unique use of the data areas. Marking and compaction are performed on both the heap and the trail. The marking and compaction algorithms use pointer reversal techniques, which obviate the need for extra stack space. However, two bits for every pointer on the heap are reserved for the garbage collection algorithm. The algorithm can work on segments of the heap, which may lead to a significant reduction of the total garbage collection time. The time of the algorithms are linear in the size of the areas.

  • 18.
    Arad, Cosmin
    et al.
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Haridi, Seif
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Kompics: a message-passing component model for building distributed systems2010Report (Other academic)
    Abstract [en]

    The Kompics component model and programming framework was designedto simplify the development of increasingly complex distributed systems. Systems built with Kompics leverage multi-core machines out of the box and they can be dynamically reconfigured to support hot software upgrades. A simulation framework enables deterministic debugging and reproducible performance evaluation of unmodified Kompics distributed systems. We describe the component model and show how to program and compose event-based distributed systems. We present the architectural patterns and abstractions that Kompics facilitates and we highlight a case study of a complex distributed middleware that we have built with Kompics. We show how our approach enables systematic development and evaluation of large-scale and dynamic distributed systems.

  • 19.
    Arad, Cosmin
    et al.
    RISE - Research Institutes of Sweden, ICT, SICS.
    Kafray, Ozair
    Ghodsi, Ali
    RISE - Research Institutes of Sweden, ICT, SICS.
    Haridi, Seif
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    GODS: Global Observatory for Distributed Systems2007Report (Other academic)
    Abstract [en]

    We propose GODS, an ecosystem for the evaluation and study of world-wide distributed and dynamic systems under a realistic emulated network environment. GODS allows the evaluation of a system's actual implementation in reproducible experiments, collecting global knowledge about the system state. Furthermore, GODS addresses the problems of debugging distributed algorithms, performance tuning, measuring bandwidth consumption, regression testing, and benchmarking similar systems, thus offering a complete evaluation environment for distributed applications. Our framework uses ModelNet for the network emulation and enhances that by (1) adding dynamism by varying link properties, partitioning the network and emulating churn, (2) offering global knowledge about the observed system by gathering statistics and events and (3) enabling the user to easily deploy, manage and monitor complex, large-scale distributed systems.

  • 20. Arafailova, Ekaterina
    et al.
    Beldiceanu, Nicolas
    Carlsson, Mats
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Flener, Pierre
    Francisco Rodríguez, María Andreína
    Pearson, Justin
    Simonis, Helmut
    Systematic Derivation of Bounds and Glue Constraints for Time-Series Constraints2016In: International Conference on Principles and Practice of Constraint Programming (CP 2016), Springer Publishing Company, 2016, p. 13-29Conference paper (Refereed)
    Abstract [en]

    Integer time series are often subject to constraints on the aggregation of the integer features of all occurrences of some pattern within the series. For example, the number of inflexions may be constrained, or the sum of the peak maxima, or the minimum of the peak widths. It is currently unknown how to maintain domain consistency efficiently on such constraints. We propose parametric ways of systematically deriving glue constraints, which are a particular kind of implied constraints, as well as aggregation bounds that can be added to the decomposition of time-series constraints [5]. We evaluate the beneficial propagation impact of the derived implied constraints and bounds, both alone and together.

  • 21. Arafailova, Ekaterina
    et al.
    Beldiceanu, Nicolas
    Douence, Rémi
    Carlsson, Mats
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Flener, Pierre
    Francisco Rodríguez, María Andreína
    Pearson, Justin
    Simonis, Helmut
    Global Constraint Catalog Volume II: Time-Series Constraints2016Other (Other academic)
    Abstract [en]

    First this report presents a restricted set of finite transducers used to synthesise structural time-series constraints described by means of a multi-layered function composition scheme. Second it provides the corresponding synthesised catalogue of structural time-series constraints where each constraint is explicitly described in terms of automata with accumulators.

  • 22.
    Ardelius, John
    et al.
    RISE, Swedish ICT, SICS. RISE, Swedish ICT, SICS, Computer Systems Laboratory. CNS.
    Mejıas, Boris
    Modeling the Performance of Ring Based DHTs in the Presence of Network Address Translators2011In: DAIS 2011Article in journal (Refereed)
    Abstract [en]

    Dealing with Network Address Translators (NATs) is a central prob- lem 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 un- available due to NATs. We investigate how the topology induced by the model affects the performance of ring based DHTs. We quantify two main performance is- sues 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.

  • 23. Arunachalam, Raghu
    et al.
    Eriksson, Joakim
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Finne, Niclas
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Janson, Sverker
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Sadeh, Norman M.
    The Supply Chain Management Game for the Trading Agent Competition 20042004Report (Other academic)
    Abstract [en]

    This report is the specification for the Trading Agent Competition Supply Chain Management Game - TAC SCM-04, to be held between July 20-22, 2004, in New York in conjunction with AAMAS-04. Based on the experience of the 2003 Trading Agent Competition a few enhancements have been added to the original game: (1)The price function has been modified to better reflect demand; (2) storage costs have been introduced; and (3) customer demand has been segmented into multiple markets.

  • 24. Aschenbruck, Nils
    et al.
    Ernst, Raphael
    Schwamborn, Matthias
    Österlind, Fredrik
    RISE, Swedish ICT, SICS.
    Voigt, Thiemo
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Poster Abstract: Adding Mobility to Wireless Sensor Network Simulations2010Conference paper (Refereed)
  • 25.
    Aslam, Mudassar
    et al.
    RISE, Swedish ICT, SICS.
    Gehrmann, Christian
    RISE, Swedish ICT, SICS, Security Lab.
    Rasmusson, Lars
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Björkman, Mats
    Securely Launching Virtual Machines on Trustworthy Platforms in a Public Cloud2012Conference paper (Refereed)
    Abstract [en]

    In this paper we consider the Infrastructure-as-a-Service (IaaS) cloud model which allows cloud users to run their own virtual machines (VMs) on available cloud computing resources. IaaS gives enterprises the possibility to outsource their process workloads with minimal effort and expense. However, one major problem with existing approaches of cloud leasing, is that the users can only get contractual guarantees regarding the integrity of the offered platforms. The fact that the IaaS user himself or herself cannot verify the provider promised cloud platform integrity, is a security risk which threatens to prevent the IaaS business in general. In this paper we address this issue and propose a novel secure VM launch protocol using Trusted Computing techniques. This protocol allows the cloud IaaS users to securely bind the VM to a trusted computer configuration such that the clear text VM only will run on a platform that has been booted into a trustworthy state. This capability builds user confidence and can serve as an important enabler for creating trust in public clouds. We evaluate the feasibility of our proposed protocol via a full scale system implementation and perform a system security analysis.

  • 26. Aurell, Erik
    et al.
    Boman, Magnus
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Carlsson, Mats
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    A trading agent built on constraint programming2002Conference paper (Refereed)
    Abstract [en]

    The Trading Agent Competition (TAC) combines a fairly realistic model of the Internet commerce of the future, including shopbots and pricebots, with a challenging problem in automated reasoning and decision making. Automated trading via auctions under severe time constraints are to be con-ducted by entering autonomous agents into TAC, assuming the role of travel agents. The TAC game rules, as well as a description of the discrete op-timization problem faced by an agent that wishes to allocate goods to its clients, are described. The TAC’01 entry “006”, encapsulating a constraint programming solution, is explained in some detail.

  • 27.
    Aurell, Erik
    et al.
    RISE - Research Institutes of Sweden, ICT, SICS.
    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.
    GENFUNK2002Report (Other academic)
    Abstract [en]

    This document summarizes the results obtained by SICS in project GENFUNK (2001). The project was carried out in collaboration with Global Genomics AB (Stockholm, Sweden). Jointly obtained results will be presented separately. Main funding was provided by Swedish Research Agency VINNOVA. Project GENFUNK studied a novel approach of measuring the global gene expression. In the method, mRNA is extracted from a tissue sample and transformed into cDNA captured on magnetic beads. This is then acted on by type IIS restriction endonucleases, which recognize certain short DNA sequences and cut the DNA close to those sequences. The resulting fragments are amplified in PCR with selected ligation fragments, and displayed in capillary electrophoresis. Determining the gene expression levels from the peak data is combinatorial optimization problem, which can in principle be solved, to give expression levels of most genes active in sampled cells, with good accuracy.

  • 28. Azzarà, Andrea
    et al.
    Mottola, Luca
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Virtual Resources for the Internet of Things2015Conference paper (Refereed)
  • 29. Baccour, Nouha
    et al.
    Koubaa, Anis
    Mottola, Luca
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Zuniga, Marco
    Habib, Youssef
    Boano, Carlo Alberto
    Alves, Mario
    Radio Link Quality Estimation in Wireless Sensor Networks: a Survey2012In: ACM Transactions on Sensor NetworksArticle in journal (Refereed)
  • 30. Baccour, Nouha
    et al.
    Koubaa, Anis
    Noda, Claro
    Fotouhi, Hossein
    Alves, Mario
    Youssef, Hossein
    Zuniga, Marco
    Boano, Carlo Alberto
    Römer, Kay
    Puccinelli, Daniele
    Mottola, Luca
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Voigt, Thiemo
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Radio Link Quality Estimation in Low-Power Wireless Networks2013 (ed. 12)Book (Refereed)
  • 31. Bagci, Ibrahim Ethem
    et al.
    Pourmirza, Mohammad Reza
    Raza, Shahid
    RISE, Swedish ICT, SICS, Security Lab.
    Roedig, Utz
    Voigt, Thiemo
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Codo: Confidential Data Storage for Wireless Sensor Networkss2012Conference paper (Refereed)
    Abstract [en]

    Many Wireless Sensor Networks (WSNs) are used to collect and process confidential information. Confidentiality must be ensured at all times and, for example, solutions for confidential communication, processing or storage are required. To date, the research community has addressed mainly the issue of confidential communication. Efficient solutions for cryptographically secured communication and associated key exchange in WSNs exist. Many WSN applications, however, rely heavily on available on-node storage space and therefore it is essential to ensure the confidentiality of stored data as well. In this paper we present Codo, a confidential data storage solution which balances platform, performance and security requirements. We implement Codo for the Contiki WSN operating system and evaluate its performance.

  • 32. Bagci, Ibrahim Ethem
    et al.
    Raza, Shahid
    RISE, Swedish ICT, SICS, Security Lab.
    Chung, Tony
    Roedig, Utz
    Voigt, Thiemo
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Combined Secure Storage and Communication for the Internet of Things2013Conference paper (Refereed)
  • 33. Bagci, Ibrahim Ethem
    et al.
    Raza, Shahid
    RISE, Swedish ICT, SICS, Security Lab.
    Roedig, Utz
    Voigt, Thiemo
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Fusion: Coalesced Confidential Storage and Communication Framework for the IoT2015In: Security and Communication Networks, ISSN 1939-0114, E-ISSN 1939-0122, Vol. 9, no 15, p. 2656-2673Article in journal (Refereed)
    Abstract [en]

    Comprehensive security mechanisms are required for a successful implementation of the Internet of Things (IoT). Existing solutions focus mainly on securing the communication links between Internet hosts and IoT devices. However, as most IoT devices nowadays provide vast amounts of flash storage space it is as well required to consider storage security within a comprehensive security framework. Instead of developing independent security solutions for storage and communication we propose Fusion, a framework which provides coalesced confidential storage and communication. Fusion uses existing secure communication protocols for the IoT such as IPsec and DTLS and re-uses the defined communication security mechanisms within the storage component. Thus, trusted mechanisms developed for communication security are extended into the storage space. Notably, this mechanism allows us to transmit requested data directly from the file system without decrypting read data blocks and then re-encrypting these for transmission. Thus, Fusion provides benefits in terms of processing speed and energy efficiency which are important aspects for resource constrained IoT devices. The paper describes the Fusion architecture and its instantiation for IPsec and DTLS based systems. We describe Fusion’s implementation and evaluate its storage overheads, communication performance and energy consumption

  • 34. Baresi, Luciano
    et al.
    Ghezzi, Carlo
    Mottola, Luca
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Loupe: Verifying Publish-Subscribe Architectures with a Magnifying Lens2011In: IEEE Transactions on Software EngineeringArticle in journal (Refereed)
  • 35. Baresi, Luciano
    et al.
    Mottola, Luca
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Dustdar, Schahram
    Building Software for the Internet of Things2015In: IEEE Internet ComputingArticle in journal (Refereed)
  • 36.
    Behboodi, Arash
    et al.
    Evarilos.
    Crombez, Pieter
    Evarilos.
    de las Heras, Jose Javier
    De Poorter, Eli
    Handziski, Vlado
    Lemic, Filip
    Moerman, Ingrid
    Van Haute, Tom
    Verhoeve, Piet
    Voigt, Thiemo
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Wirström, Niklas
    RISE, Swedish ICT, SICS.
    Wolisz, Adam
    Evaluation of RF-based Indoor Localization Solutions for the Future Internet2013Conference paper (Refereed)
  • 37. Behboodi, Arash
    et al.
    Wirström, Niklas
    RISE, Swedish ICT, SICS.
    Lemic, Filip
    Voigt, Thiemo
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Wolisz, Adam
    Interference Effect on Localization Solutions: Signal Feature Perspective2015Conference paper (Refereed)
    Abstract [en]

    We study the effect of interference on localization algorithms through the study of the interference effect on signal features that are used for localization. Particularly, the effect of interference on packet-based Received Signal Strength Indicator (RSSI), reported by IEEE 802.11 and IEEE 802.15.4 technologies, and on Time of Flight (ToF), reported by IEEE 802.15.4 technology, is studied using both theoretical discussions and experimental verifications. As for the RSSI values, using an information theoretic formulation, we distinguish three operational regimes and we show that the RSSI values, in dBm, remain unchanged in the noise-limited regime, increase almost linearly with interference power in dBm in the interference-limited regime and cannot be obtained due to packet loss in the collision regime. The maximum observable RSSI variation is dependent on the transmission rate and Signal to Noise Ratio (SNR). We also show that ToF is, interestingly, decreased under interference which is caused in the symbol synchronization procedure at the receiver. After providing the experimental results, we discuss how the localization algorithms are affected by interference.

  • 38. Beldiceanu, Nicolas
    et al.
    Carlsson, Mats
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    A New multi-resource cumulatives constraint with negative heights2002In: CP'2002, Principles and Practice of Constraint Programming, Springer-Verlag , 2002, 1, Vol. 2470, p. 63-79Conference paper (Refereed)
    Abstract [en]

    This paper presents a new cumulatives constraint which generalizes the original cumulative constraint in different ways. The two most important aspects consist in permitting multiple cumulative resources as well as negative heights for the resource consumption of the tasks. This allows modeling in an easy way new scheduling and planning problems. The introduction of negative heights has forced us to come up with new propagation algorithms and to revisit existing ones. The first propagation algorithm is derived from an idea called sweep which is extensively used in computational geometry; the second algorithm is based on a combination of sweep and constructive disjunction, while the last is a generalization of task intervals to this new context. A real-life timetabling problem originally motivated this constraint which was implemented within the SICStus finite domain solver and evaluated against different problem patterns.

  • 39.
    Beldiceanu, Nicolas
    et al.
    RISE - Research Institutes of Sweden, ICT, SICS.
    Carlsson, Mats
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    A New Multi-Resource cumulatives Constraint with Negative Heights2001Report (Other academic)
    Abstract [en]

    This paper presents a new cumulatives constraint which generalizes the original cumulative constraint in different ways. The two most important aspects consist in permitting multiple cumulative resources as well as negative heights for the resource consumption of the tasks. This allows modeling in an easy way new scheduling and planning problems. The introduction of negative heights has forced us to come up with new propagation algorithms and to revisit existing ones. The first propagation algorithm is derived from an idea called sweep which is extensively used in computational geometry; the second algorithm is based on a combination of sweep and constructive disjunction, while the last is a generalization of task intervals to this new context. A real-life timetabling problem originally motivated this constraint which was implemented within the SICStus finite domain solver and evaluated against different problem patterns.

  • 40.
    Beldiceanu, Nicolas
    et al.
    RISE - Research Institutes of Sweden, ICT, SICS.
    Carlsson, Mats
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Constructive Cardinality2001Report (Other academic)
    Abstract [en]

    We describe a set of necessary conditions that are useful for generating propagation algorithms for the cardinality operator as well as for over-constrained problems with preferences. Constructive disjunction as well as the entailments rules originally proposed for the cardinality operator can be seen as simple cases of these necessary conditions. In addition these necessary conditions have the advantage of providing more pruning.

  • 41.
    Beldiceanu, Nicolas
    et al.
    RISE - Research Institutes of Sweden, ICT, SICS.
    Carlsson, Mats
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Revisiting the cardinality operator and introducing the cardinality-path constraint family2001Conference paper (Refereed)
    Abstract [en]

    This paper presents generic propagation algorithms for the cardinality-path constraint family. This is a restricted form of the cardinality operator that allows stating constraints on sliding sequences of consecutive variables. Taking advantage of these restrictions permits coming up with more efficient algorithms. Moreover the paper shows how to extend these propagation algorithms in order to partially integrate external constraints that have to hold. From an application point of view the cardinality-path constraint allows to express a huge variety of regulation constraints occurring in personnel planning problems.

  • 42.
    Beldiceanu, Nicolas
    et al.
    RISE - Research Institutes of Sweden, ICT, SICS.
    Carlsson, Mats
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Sweep as a generic pruning technique applied to constraint relaxation2001Conference paper (Refereed)
    Abstract [en]

    We introduce a new generic filtering algorithm for handling constraint relaxation within constraint programming. More precisely, we first present a generic pruning technique, which is useful for a special case of the cardinality operator where all the constraints have at least two variables in common. This method is based on a generalisation of a sweep algorithm, which handles a conjunction of constraints to the case where one just knows the minimum and maximum number of constraints that have to hold. The main benefit of this new technique comes from the fact that, even if we don't know which, and exactly how many constraints, will hold in the final solution, we can still prune the variables of those constraints right from the beginning according to the minimum and maximum number of constraints that have to hold. We then show how to extend the previous sweep algorithm in order to handle preferences among constraints. Finally, we specialise this technique to an extension of the non-overlapping rectangles constraint, where we permit controlling how many non-overlapping constraints should hold. This allows handling over-constrained placement problems and provides constraint propagation even if some non-overlapping constraints have to be relaxed.

  • 43.
    Beldiceanu, Nicolas
    et al.
    RISE - Research Institutes of Sweden, ICT, SICS.
    Carlsson, Mats
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Sweep as a generic pruning technique applied to the non-overlapping rectangles constraint2001Conference paper (Refereed)
    Abstract [en]

    We first present a generic pruning technique, which aggregates several constraints sharing some variables. The method is derived from an idea called sweep, which is extensively used, in computational geometry. A first benefit of this technique comes from the fact that it can be applied on several families of global constraints. A second main advantage is that it does not lead to any memory consumption problem since it only requires temporary memory that can be reclaimed after each invocation of the method. We then specialise this technique to the non-overlapping rectangles constraint, describe several optimisations, and give an empirical evaluation based on six sets of test instances with different characteristics.

  • 44.
    Beldiceanu, Nicolas
    et al.
    RISE - Research Institutes of Sweden, ICT, SICS.
    Carlsson, Mats
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Sweep as a Generic Pruning Technique Applied to the Non-Overlapping Rectangles Constraint2001Report (Other academic)
    Abstract [en]

    We first present a generic pruning technique which aggregates several constraints sharing some variables. The method is derived from an idea called \dfn{sweep} which is extensively used in computational geometry. A first benefit of this technique comes from the fact that it can be applied on several families of global constraints. A second main advantage is that it does not lead to any memory consumption problem since it only requires temporary memory that can be reclaimed after each invocation of the method. We then specialize this technique to the non-overlapping rectangles constraint, describe several optimizations, and give an empirical evaluation based on six sets of test instances of different pattern.

  • 45. Beldiceanu, Nicolas
    et al.
    Carlsson, Mats
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Debruyne, Romuald
    Petit, Thierry
    Reformulation of global constraints based on constraint checkers2005In: Constraints, Vol. 10Article in journal (Refereed)
    Abstract [en]

    This article deals with global constraints for which the set of solutions can be recognized by an extended finite automaton whose size is bounded by a polynomial in n, where n is the number of variables of the corresponding global constraint. By reducing the automaton to a conjunction of signature and transition constraints we show how to systematically obtain an automaton reformulation. Under some restrictions on the signature and transition constraints, this reformulation maintains arc-consistency. An implementation based on some constraints as well as on the metaprogramming facilities of SICStus Prolog is available. For a restricted class of automata we provide an automaton reformulation for the relaxed case, where the violation cost is the minimum number of variables to unassign in order to get back to a solution.

  • 46. Beldiceanu, Nicolas
    et al.
    Carlsson, Mats
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Demassey, Sophie
    Petit, Thierry
    Graph properties based filtering2006Conference paper (Refereed)
  • 47. Beldiceanu, Nicolas
    et al.
    Carlsson, Mats
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Demassey, Sophie
    Petit, Thierry
    Graph Properties Based Filtering2006Report (Other academic)
    Abstract [en]

    This report presents a generic filtering scheme, based on the graph description of global constraints. This description is defined by a network of binary constraints and a list of elementary graph properties: each solution of the global constraint corresponds to a subgraph of the initial network, retaining only the satisfied binary constraints, and which fulfills all the graph properties. The graph-based filtering identifies the arcs of the network that belong or not to the solution subgraphs. The objective is to build, besides a catalog of global constraints, also a list of systematic filtering rules based on a limited set of graph properties. We illustrate this principle on some common graph properties and provide computational experiments of the effective filtering on the "group" constraint.

  • 48. Beldiceanu, Nicolas
    et al.
    Carlsson, Mats
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Demassey, Sophie
    Poder, Emmanuel
    New Filtering for the Cumulative Constraint in the Context of Non-Overlapping Rectangles2011In: Annals of Operations Research, ISSN 0254-5330, E-ISSN 1572-9338, Vol. 1, p. 27-50Article in journal (Refereed)
    Abstract [en]

    This article describes new filtering methods for the Cumulative constraint. The first method introduces bounds for the so called longest cumulative hole problem and shows how to use these bounds in the context of the Non-Overlapping constraint. The second method introduces balancing knapsack constraints which relate the total height of the tasks that end at a specific time-point with the total height of the tasks that start at the same time-point. Experiments on tight rectangle packing problems show that these methods drastically reduce both the time and the number of backtracks for finding all solutions as well as for finding the first solution. For example, we found without backtracking all solutions to 65 perfect square instances of order 22-25 and sizes ranging from 192x192 to 661x661.

  • 49. Beldiceanu, Nicolas
    et al.
    Carlsson, Mats
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Derrien, A.
    Schutt, A.
    Stuckey, P.
    Range-consistent forbidden regions of Allen's relations2016Report (Other academic)
    Abstract [en]

    For all 8192 combinations of Allen's 13 relations between one task with origin oi and fixed length li and another task with origin oj and fixed length lj, we give a formula F(min(oj), max(oj), li, lj), where min(oj) and max(oj) respectively denote the earliest and the latest origin of task j, evaluating to a set of integers which are infeasible for oi for the given combination. Such forbidden regions are useful e.g. in a range-consistency maintaining propagator for an Allen constraint in finite domain constraint programming.

  • 50. Beldiceanu, Nicolas
    et al.
    Carlsson, Mats
    RISE, Swedish ICT, SICS, Computer Systems Laboratory.
    Douence, Rémi
    Simonis, Helmut
    Using finite transducers for describing and synthesising structural time-series constraints2015In: Constraints, ISSN 1383-7133, E-ISSN 1572-9354, Vol. 21, p. 22-40Article in journal (Refereed)
    Abstract [en]

    We describe a large family of constraints for structural time series by means of function composition. These constraints are on aggregations of features of patterns that occur in a time series, such as the number of its peaks, or the range of its steepest ascent. The patterns and features are usually linked to physical properties of the time series generator, which are important to capture in a constraint model of the system, i.e. a conjunction of constraints that produces similar time series. We formalise the patterns using finite transducers, whose output alphabet corresponds to semantic values that precisely describe the steps for identifying the occurrences of a pattern. Based on that description, we automatically synthesise automata with accumulators, as well as constraint checkers. The description scheme not only unifies the structure of the existing 30 time-series constraints in the Global Constraint Catalogue, but also leads to over 600 new constraints, with more than 100,000 lines of synthesised code.

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