Logo: to the web site of Uppsala University

uu.sePublications from Uppsala University
Change search
Refine search result
1234567 1 - 50 of 440
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1.
    Abdulla, PA
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology, Computer Systems. DEPARTMENT OF COMPUTER SYSTEMS.
    Boasson, L
    Bouajjani, A
    Effective Lossy Queue Languages.2001In: ICALP'2001, 28th Int. Colloquium on Automata, Languages and Programmming., 2001Conference paper (Refereed)
  • 2.
    Abdulla, PA
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology. DEPARTMENT OF COMPUTER SYSTEMS.
    Jonsson, B
    Channel Abstractions in Protocol Verification2001In: CONCUR'2001, 12th Int. Conf. on Concurrency Theory, 2001Conference paper (Refereed)
  • 3.
    Abdulla, Parosh A.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Delzanno, Giorgio
    Univ Genoa, DIBRIS, Genoa, Italy..
    Parameterized verification2016In: International Journal on Software Tools for Technology Transfer, ISSN 1433-2779, E-ISSN 1433-2787, Vol. 18, no 5, p. 469-473Article in journal (Other academic)
    Abstract [en]

    The goal of parameterized verification is to prove the correctness of a system specification regardless of the number of its components. The problem is of interest in several different areas: verification of hardware design, multithreaded programs, distributed systems, and communication protocols. The problem is undecidable in general. Solutions for restricted classes of systems and properties have been studied in areas like theorem proving, model checking, automata and logic, process algebra, and constraint solving. In this introduction to the special issue, dedicated to a selection of works from the Parameterized Verification workshop PV '14 and PV '15, we survey some of the works developed in this research area.

  • 4.
    Abdulla, Parosh A.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Delzanno, Giorgio
    Univ Genoa, Genoa, Italy..
    Montali, Marco
    Free Univ Bolzano, Bolzano, Italy..
    Well Structured Transition Systems with History2015In: Electronic Proceedings in Theoretical Computer Science, E-ISSN 2075-2180, no 193, p. 115-128Article in journal (Refereed)
    Abstract [en]

    We propose a formal model of concurrent systems in which the history of a computation is explicitly represented as a collection of events that provide a view of a sequence of configurations. In our model events generated by transitions become part of the system configurations leading to operational semantics with historical data. This model allows us to formalize what is usually done in symbolic verification algorithms. Indeed, search algorithms often use meta-information, e.g., names of fired transitions, selected processes, etc., to reconstruct (error) traces from symbolic state exploration. The other interesting point of the proposed model is related to a possible new application of the theory of well-structured transition systems (wsts). In our setting wsts theory can be applied to formally extend the class of properties that can be verified using coverability to take into consideration (ordered and unordered) historical data. This can be done by using different types of representation of collections of events and by combining them with wsts by using closure properties of well-quasi orderings.

  • 5. Abdulla, Parosh Aziz
    Carrying Probabilities to the Infinite World2011In: CONCUR'2011, 22nd International Conference on Concurrency Theory., 2011Conference paper (Refereed)
  • 6.
    Abdulla, Parosh Aziz
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology. DEPARTMENT OF COMPUTER SYSTEMS.
    Using (Timed) Petri Nets for Verification of Parametrized (Timed) Systems2001In: VEPAS'2001, Verification of Parameterized Systems, 2001Conference paper (Refereed)
  • 7.
    Abdulla, Parosh Aziz
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Atig, Mohamed Faouzi
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Kaxiras, Stefanos
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Architecture and Computer Communication.
    Leonardsson, Carl
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Ros, Alberto
    Zhu, Yunyun
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Fencing programs with self-invalidation and self-downgrade2016In: Formal Techniques for Distributed Objects, Components, and Systems, Springer, 2016, p. 19-35Conference paper (Refereed)
  • 8.
    Abdulla, Parosh Aziz
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Chen, Yu-Fang
    Clemente, Lorenzo
    Holík, Lukás
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Hong, Chih-Duo
    Mayr, Richard
    Vojnar, Tomás
    Advanced Ramsey-based Büchi automata inclusion testing2011In: CONCUR 2011 — Concurrency Theory, Springer Berlin/Heidelberg, 2011, p. 187-202Conference paper (Refereed)
  • 9.
    Abdulla, Parosh Aziz
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Delzanno, Giorgio
    Univ Genoa, I-16126 Genoa, Italy..
    Rezine, Othmane
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems. Uppsala Univ, Uppsala, Sweden..
    Sangnier, Arnaud
    Univ Paris Diderot, CNRS, LIAFA, Paris, France..
    Traverso, Riccardo
    FBK, Trento, Italy..
    Parameterized verification of time-sensitive models of ad hoc network protocols2016In: Theoretical Computer Science, ISSN 0304-3975, E-ISSN 1879-2294, Vol. 612, p. 1-22Article in journal (Refereed)
    Abstract [en]

    We study decidability and undecidability results for parameterized verification of a formal model of timed Ad Hoc network protocols. The communication topology is defined by an undirected graph and the behaviour of each node is defined by a timed automaton communicating with its neighbours via broadcast messages. We consider parameterized verification problems formulated in terms of reachability. In particular we are interested in searching for an initial configuration from which an individual node can reach an error state. We study the problem for dense and discrete time and compare the results with those obtained for (fully connected) networks of timed automata.

  • 10.
    Abdulla, Parosh Aziz
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology.
    Delzanno, Giorgio
    Van Begin, Laurent
    A classification of the expressive power of well-structured transition systems2011In: Information and Computation, ISSN 0890-5401, E-ISSN 1090-2651, Vol. 209, no 3, p. 248-279Article in journal (Refereed)
    Abstract [en]

    We compare the expressive power of a class of well-structured transition systems that includes relational automata (extensions of), Petri nets, lossy channel systems, constrained multiset rewriting systems, and data nets. For each one of these models we study the class of languages generated by labeled transition systems describing their semantics. We consider here two types of accepting conditions: coverability and reachability of a fixed a priori configuration. In both cases we obtain a strict hierarchy in which constrained multiset rewriting systems is the most expressive model.

  • 11.
    Abdulla, Parosh Aziz
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology, Computer Systems. Datorteknik.
    Jonsson, Bengt
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology, Computer Systems. Datorteknik.
    Model checking of systems with many identical timed processes2003In: Theoretical Computer Science, ISSN 0304-3975, Vol. 290, no 1, p. 241-264Article in journal (Refereed)
  • 12. Abdulla, Parosh Aziz
    et al.
    Leino, Rustan
    TACAS'2011, 17th International ConferenceTools and Algorithms for the Construction and Analysis of Systems.2011Conference proceedings (editor) (Refereed)
  • 13.
    Abdulla, Parosh Aziz
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Richard, Mayr
    Computing Optimal Coverability Costs in Priced Timed Petri Nets2011In: LICS'2011, Proceedings of the 26th Annual IEEE Symposium on Logic in Computer Science, 2011, p. 399-408Conference paper (Refereed)
    Abstract [en]

    We consider timed Petri nets, i.e., unbounded Petri nets where each token carries a real-valued clock. Transition arcs are labeled with time intervals, which specify constraints on the ages of tokens. Our cost model assigns token storage costs per time unit to places, and firing costs to transitions. We study the cost to reach a given control-state. In general, a cost-optimal run may not exist. However, we show that the infimum of the costs is computable.

  • 14.
    Abdulla, Parosh
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology, Computer Systems. DoCS.
    Ben Henda, Noomene
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology, Computer Systems. DoCS.
    Mayr, Richard
    Sandberg, Sven
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology, Computer Systems. Datalogi.
    Limiting Behavior of Markov Chains with Eager Attractors2006In: Third International Conference on the Quantitative Evaluation of Systems (QEST), 2006, p. 253-262Conference paper (Refereed)
  • 15.
    Ahlgren, Bengt
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Computer Systems. Swedish Institute of Computer Science.
    Improving Computer Communication Performance by Reducing Memory Bandwidth Consumption1997Doctoral thesis, comprehensive summary (Other academic)
  • 16.
    Alirezaie, Marjan
    et al.
    Örebro University.
    Renoux, Jennifer
    Örebro University.
    Köckemann, Uwe
    Örebro University.
    Kristoffersson, Annica
    Örebro University.
    Karlsson, Lars
    Örebro University.
    Blomqvist, Eva
    SICS East.
    Tsiftes, Nicolas
    SICS.
    Voigt, Thiemo
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Architecture and Computer Communication. SICS.
    Loutfi, Amy
    Örebro University.
    An Ontology-based Context-aware System for Smart Homes: E-care@ home2017In: Sensors, E-ISSN 1424-8220, Vol. 17, no 7Article in journal (Refereed)
  • 17. Alonso, Juan M.
    et al.
    Nordhamn, Amanda
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Architecture and Computer Communication.
    Olofsson, Simon
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Architecture and Computer Communication.
    Voigt, Thiemo
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Architecture and Computer Communication.
    Bounds on the lifetime of wireless sensor networks with lossy links and directional antennas2016In: Wireless Network Performance Enhancement via Directional Antennas: Models, Protocols, and Systems, Boca Raton, FL: CRC Press, 2016, p. 329-361Chapter in book (Refereed)
  • 18.
    Amnell, Tobias
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Division of Computer Systems. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Code synthesis for timed automata2003Licentiate thesis, monograph (Other scientific)
    Abstract [en]

    In this thesis, we study executable behaviours of timed models. The focus is on synthesis of executable code with predictable behaviours from high level abstract models. We assume that a timed system consists of two parts: the control software and the plant (i.e. the environment to be controlled). Both are modelled as timed automata extended with real time tasks. We consider the extended timed automata as design models.

    We present a compilation procedure to transform design models to executable code including a run-time scheduler (run time system) preserving the correctness and schedulability of the models. The compilation procedure has been implemented in a prototype C-code generator for the brickOS operating system included in the Times tool. We also present an animator, based on hybrid automata, to be used to describe a simulated environment (i.e. the plant) for timed systems. The tasks of the hybrid automata define differential equations and the animator uses a differential equations solver to calculate step-wise approximations of real valued variables. The animated objects, described as hybrid automata, are compiled by the Times tool into executable code using a similar procedure as for controller software.

    To demonstrate the applicability of timed automata with tasks as a design language we have developed the control software for a production cell. The production cell is built in LEGO and is controlled by a Hitachi H8 based LEGO-Mindstorms control brick. The control software has been analysed (using the Times tool) for schedulability and other safety properties. Using results from the analysis we were able to avoid generating code for parts of the design that could never be reached, and could also limit the amount of memory allocated for the task queue.

    Download full text (pdf)
    fulltext
  • 19.
    Amouzgar, Kaveh
    et al.
    Högskolan i Jönköping, JTH, Produktutveckling.
    Cenanovic, Mirza
    Högskolan i Jönköping, JTH, Produktutveckling.
    Salomonsson, Kent
    Högskolan i Jönköping, JTH, Produktutveckling.
    Multi-objective optimization of material model parameters of an adhesive layer by using SPEA22015In: Advances in structural and multidisciplinary optimization: Proceedings of the 11th World Congress of Structural and Multidisciplinary Optimization (WCSMO-11) / [ed] Qing Li, Grant P Steven, Zhongpu (Leo) Zhang, The International Society for Structural and Multidisciplinary Optimization (ISSMO) , 2015, p. 249-254Conference paper (Refereed)
    Abstract [en]

    The usage of multi material structures in industry, especially in the automotive industry are increasing. To overcome the difficulties in joining these structures, adhesives have several benefits over traditional joining methods. Therefore, accurate simulations of the entire process of fracture including the adhesive layer is crucial. In this paper, material parameters of a previously developed meso mechanical finite element (FE) model of a thin adhesive layer are optimized using the Strength Pareto Evolutionary Algorithm (SPEA2). Objective functions are defined as the error between experimental data and simulation data. The experimental data is provided by previously performed experiments where an adhesive layer was loaded in monotonically increasing peel and shear. Two objective functions are dependent on 9 model parameters (decision variables) in total and are evaluated by running two FEsimulations, one is loading the adhesive layer in peel and the other in shear. The original study converted the two objective functions into one function that resulted in one optimal solution. In this study, however, a Pareto frontis obtained by employing the SPEA2 algorithm. Thus, more insight into the material model, objective functions, optimal solutions and decision space is acquired using the Pareto front. We compare the results and show good agreement with the experimental data.

  • 20.
    Aris, Ahmet
    et al.
    Istanbul Technical University.
    Oktuğ, Sema
    Istanbul Technical University.
    Voigt, Thiemo
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Architecture and Computer Communication.
    Security of Internet of Things for a Reliable Internet of Services2018In: Autonomous Control for a Reliable Internet of Services: Methods, Models, Approaches, Techniques, Algorithms, and Tools / [ed] Ivan Ganchev, R. D. van der Mei, Hans van den Berg, Cham , 2018Chapter in book (Refereed)
    Download full text (pdf)
    fulltext
  • 21.
    Asgharzadeh, Ashkan
    et al.
    Univ Murcia, Comp Engn Dept, Murcia 30100, Spain..
    Cebrian, Juan M.
    Univ Murcia, Comp Engn Dept, Murcia 30100, Spain..
    Perais, Arthur
    Univ Grenoble Alpes, CNRS, Grenoble INP, Inst Engn,TIMA, Grenoble, France..
    Kaxiras, Stefanos
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Architecture and Computer Communication. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Division of Computer Systems.
    Ros, Alberto
    Univ Murcia, Comp Engn Dept, Murcia 30100, Spain..
    Free Atomics: Hardware Atomic Operations without Fences2022In: PROCEEDINGS OF THE 2022 THE 49TH ANNUAL INTERNATIONAL SYMPOSIUM ON COMPUTER ARCHITECTURE (ISCA '22), ASSOC COMPUTING MACHINERY Association for Computing Machinery (ACM), 2022, p. 14-26Conference paper (Refereed)
    Abstract [en]

    Atomic Read-Modify-Write (RMW) instructions are primitive synchronization operations implemented in hardware that provide the building blocks for higher-abstraction synchronization mechanisms to programmers. According to publicly available documentation, current x86 implementations serialize atomic RMW operations, i.e., the store buffer is drained before issuing atomic RMWs and subsequent memory operations are stalled until the atomic RMW commits. This serialization, carried out by memory fences, incurs a performance cost which is expected to increase with deeper pipelines. This work proposes Free atomics, a lightweight, speculative, deadlock-free implementation of atomic operations that removes the need for memory fences, thus improving performance, while preserving atomicity and consistency. Free atomics is, to the best of our knowledge, the first proposal to enable store-to-load forwarding for atomic RMWs. Free atomics only requires simple modifications and incurs a small area overhead (15 bytes). Our evaluation using gem5-20 shows that, for a 32-core configuration, Free atomics improves performance by 12.5%, on average, for a large range of parallel workloads and 25.2%, on average, for atomic-intensive parallel workloads over a fenced atomic RMW implementation.

  • 22. Aslani, Mohammad
    et al.
    Mesgari, Mohammad Saadi
    Seipel, Stefan
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Division of Visual Information and Interaction. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computerized Image Analysis and Human-Computer Interaction.
    Wiering, Marco
    Developing adaptive traffic signal control by actor-critic and direct exploration methods2019In: Proceedings of the Institution of Civil Engineers: Transport, ISSN 0965-092X, E-ISSN 1751-7710, Vol. 172, no 5, p. 289-298Article in journal (Refereed)
  • 23.
    Atig, Mohamed Faouzi
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Bouajjani, Ahmed
    Burckhardt, Sebastian
    Musuvathi, Madanlal
    What's decidable about weak memory models?2012In: Programming Languages and Systems, Springer Berlin/Heidelberg, 2012, p. 26-46Conference paper (Refereed)
    Abstract [en]

    We investigate the decidability of the state reachability problem in finite-state programs running under weak memory models. In [3], we have shown that this problem is decidable for TSO and its extension with the write-to-write order relaxation, but beyond these models nothing is known to be decidable. Moreover, we have shown that relaxing the program order by allowing reads or writes to overtake reads leads to undecidability. In this paper, we refine these results by sharpening the (un)decidability frontiers on both sides. On the positive side, we introduce a new memory model NSW (for non-speculative writes) that extends TSO with the write-to-write relaxation, the read-to-read relaxation, and support for partial fences. We present a backtrack-free operational model for NSW, and prove that it does not allow causal cycles (thus barring pathological out-of-thin-air effects). On the negative side, we show that adding the read-to-write relaxation to TSO causes undecidability, and that adding non-atomic writes to NSW also causes undecidability. Our results establish that NSW is the first known hardware-centric memory model that is relaxed enough to permit both delayed execution of writes and early execution of reads for which the reachability problem is decidable.

  • 24.
    Bagci, Ibrahim Ethem
    et al.
    Univ Lancaster, Sch Comp & Commun, Lancaster, England.
    Raza, Shahid
    SICS Swedish ICT, Kista, Sweden.
    Roedig, Utz
    Univ Lancaster, Sch Comp & Commun, Lancaster, England.
    Voigt, Thiemo
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Architecture and Computer Communication. SICS Swedish ICT, Kista, Sweden.
    Fusion: Coalesced Confidential Storage and Communication Framework for the IoT2016In: 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 that provides coalesced confidential storage and communication. Fusion uses existing secure communication protocols for the IoT such as Internet protocol security (IPsec) and datagram transport layer security (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. This paper describes the Fusion architecture and its instantiation for IPsec-based and DTLS-based systems. We describe Fusion's implementation and evaluate its storage overheads, communication performance, and energy consumption.

  • 25.
    Behboodi, Arash
    et al.
    TU Berlin.
    Wirström, Niklas
    SICS.
    Lemic, Filip
    TU Berlin.
    Voigt, Thiemo
    SICS.
    Wolisz, Adam
    TU Berlin.
    Interference Effect on Localization Solutions: Signal Feature Perspective2015Conference paper (Refereed)
  • 26.
    Bengtsson, Johan
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Division of Computer Systems. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Efficient symbolic state exploration of timed systems: Theory and implementation2001Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Timing aspects are important for the correctness of safety-critical systems. It is crucial that these aspects are carefully analysed in designing such systems. UPPAAL is a tool designed to automate the analysis process. In UPPAAL, a system under construction is described as a network of timed automata and the desired properties of the system can be specified using a query language. Then UPPAAL can be used to explore the state space of the system description to search for states violating (or satisfying) the properties. If such states are found, the tool provides diagnostic information, in form of executions leading to the states, to help the desginers, for example, to locate bugs in the design.

    The major problem for UPPAAL and other tools for timed systems to deal with industrial-size applications is the state space explosion. This thesis studies the sources of the problem and develops techniques for real-time model checkers, such as UPPAAL, to attack the problem. As contributions, we have developed the notion of committed locations to model atomicity and local-time semantics for timed systems to allow partial order reductions, and a number of implementation techniques to reduce time and space consumption in state space exploration. The techniques are studied and compared by case studies. Our experiments demonstrate significant improvements on the performance of UPPAAL.

    Download full text (pdf)
    fulltext
  • 27.
    Berg, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Division of Computer Systems. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Methods for run time analysis of data locality2003Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    The growing gap between processor clock speed and DRAM access time puts new demands on software and development tools. Deep memory hierarchies and high cache miss penalties in present and emerging computer systems make execution time sensitive to data locality. Therefore, developers of performance-critical applications and optimizing compilers must be aware of data locality and maximize cache utilization to produce fast code. To aid the optimization process and help understanding data locality, we need methods to analyze programs and pinpoint poor cache utilization and possible optimization opportunities.

    Current methods for run-time analysis of data locality and cache behavior include functional cache simulation, often combined with set sampling or time sampling, other regularity metrics based on strides and data streams, and hardware monitoring. However, they all share the trade-off between run-time overhead, accuracy and explanatory power.

    This thesis presents methods to efficiently analyze data locality at run time based on cache modeling. It suggests source-interdependence profiling as a technique for examining the cache behavior of applications and locating source code statements and/or data structures that cause poor cache utilization. The thesis also introduces a novel statistical cache-modeling technique, StatCache. Rather than implementing a functional cache simulator, StatCache estimates the miss ratios of fully-associative caches using probability theory. A major advantage of the method is that the miss ratio estimates can be based on very sparse sampling. Further, a single run of an application is enough to estimate the miss ratio of caches of arbitrary sizes and line sizes and to study both spatial and temporal data locality.

    Download full text (ps)
    fulltext
  • 28.
    Berg, Therese
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology, Computer Systems. datorteknik.
    Jonsson, Bengt
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology, Computer Systems. datorteknik.
    Raffelt, Harald
    Regular Inference for State Machines with Parameters.2006In: Fundamental Approaches to Software Engineering, 9th International Conference, FASE 2006,, 2006, p. 107-121Conference paper (Refereed)
    Abstract [en]

    We present experiences from a case study where a model-based approach to black-box testing is applied to verify that a Wireless Application Protocol (WAP) gateway conforms to its specification.The WAP gateway is developed by Ericsson and used in mobile telephone networks to connect mobile phones with the Internet. We focus on testing the software implementing the session (WSP) and transaction (WTP) layers of the WAP protocol. These layers, and their surrounding environment, are described as a network of timed automata. To model the many sequence numbers (from a large domain) used in the protocol, we introduce an abstraction technique. We believe the suggested abstraction

    technique will prove useful to model and analyse other similar protocols with sequence numbers, in particular in the context of model-based testing.

    A complete test bed is presented, which includes generation and execution of test cases. It takes as input a model and a coverage criterion expressed as an observer, and returns a verdict for each test case. The test bed includes existing

    tools from Ericsson for test-case execution. To generate test suites, we use our own tool CoVer --- a new test-case generation tool based on the real-time model-checker Uppaal.

  • 29.
    Berg, Therese
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology, Computer Systems. Department of Computer Systems.
    Raffelt, Harald
    Model-based Testing of Reactive Systems: 19 Model Checking2005Chapter in book (Refereed)
  • 30.
    Berglund, Anders
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    A Framework to study learning in an internationally distributed course.2003In: Communities of Practise.: Research Proceedings of the 10th Association for Learning Technology Conference (ALT-C 2003), 2003, p. 27-39Conference paper (Refereed)
  • 31.
    Berglund, Anders
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Learning computer systems in a distributed course: Problematizing content and context.2002In: Proceedings of the European Association for Research on Learning and Instruction, SIG 10, Current Issues in Phenomenography, 2002Conference paper (Refereed)
    Abstract [en]

    In this paper, a research study of learning computer systems in a complex, internationally distributed course environment is described. The relation between a learner and the object of his/her studies being in focus in phenomenographic research is enhance

  • 32.
    Berglund, Anders
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology. Datorteknik. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    What is good teaching of computer networks?.2003In: Proceedings of 33rd Annual Frontiers in Education, 2003, p. 2SD13-2SD19Conference paper (Refereed)
  • 33.
    Berglund, Anders
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology. Datorteknik. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Booth, Shirley
    Are you guys really concerned about the grades?2002In: Proceedings of ISCRAT2002, 2002Conference paper (Refereed)
  • 34.
    Berglund, Anders
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Pears, Arnold
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Students' Understanding of Networks in an Internationally Distributed Course.2003In: Proceedings of 3rd IEEE International Conference of Advanced Learning Technologies (ICALT 2003)., 2003, p. 380-381Conference paper (Refereed)
  • 35.
    Bergquist, Jonatan
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Division of Computing Science.
    Blockchain Technology and Smart Contracts: Privacy-preserving Tools2017Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The purpose of this Master's thesis is to explore blockchain technology and smart contracts as a way of building privacy-sensitive applications. The main focus is on a medication plan containing prescriptions, built on a blockchain system of smart contracts. This is an example use case, but the results can be transferred to other ones where sensitive data is being shared and a proof of validity or authentication is needed. First the problem is presented, why medication plans are in need of digitalisation and why blockchain technology is a fitting technology for implementing such an application. Then blockchain technology is explained, since it is a very new and relatively unfamiliar IT construct. Thereafter, a design is proposed for solving the problem. A system of smart contracts was built to prove how such an application can be built, and suggested guidelines for how a blockchain system should be designed to fulfil the requirements that were defined. Finally, a discussion is held regarding the applicability of different blockchain designs to the problem of privacy-handling applications.

    Download full text (pdf)
    fulltext
  • 36. Bernáld, Helena
    et al.
    Cajander, Åsa
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computerized Image Analysis and Human-Computer Interaction.
    Daniels, Mats
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Kultur, Can
    Löfström, Anette
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computerized Image Analysis and Human-Computer Interaction.
    McDermott, Roger
    Russell Dag, Lori
    Intercultural competence in global collaboration courses in computer engineering2012In: Advances in Design for Cross-Cultural Activities: Part I, Boca Raton, FL: CRC Press, 2012, p. 351-361Conference paper (Refereed)
  • 37.
    Björnfot, Lars
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Computer Systems.
    Specification and Implementation of Distributed Real-Time Systems for Embedded Applications1996Doctoral thesis, comprehensive summary (Other academic)
  • 38.
    Bleichner, Andreas
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Division Vi3.
    Hermansson, Nils
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Division Vi3.
    Investigating the usefulness of a generative AI when designing user interfaces2023Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Generative AI is a hot topic as of 2023, with huge financial investments in the industry. The areas of use for it are rapidly expanding. One potential benefit of generative AI could be in the field of UX design.For this master's thesis, a Stable Diffusion model has been fine-tuned to create pictures of login screens based on text prompts written by a user. A set of these pictures have been used in a prototype and the concept has been evaluated through user tests. The prototype and the concept of using generative AI in UX design received a positive reception from testers. It was established that further work on the fine-tuned model and how to use it as a tool is required for it to be effectively integrated into the design process of user interfaces.

    Download full text (pdf)
    fulltext
  • 39.
    Bohlin, Therese
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Division of Computer Systems. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Regular Inference for Communication Protocol Entities2009Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    A way to create well-functioning computer systems is to automate error detection in the systems. Automated techniques for finding errors, such as testing and formal verification, requires a model of the system. The technique for constructing deterministic finite automata (DFA) models, without access to the source code, is called regular inference. The technique provides sequences of input, so called membership queries, to a system, observes the responses, and infers a model from the input and responses.

    This thesis presents work to adapt regular inference to a certain kind of systems: communication protocol entities. Such entities interact by sending and receiving messages consisting of a message type and a number of parameters, each of which potentially can take on a large number of values. This may cause a model of a communication protocol entity inferred by regular inference, to be very large and take a long time to infer. Since regular inference creates a model from the observed behavior of a communication protocol entity, the model may be very different from a designer's model of the system's source code.

    This thesis presents adaptations of regular inference to infer more compact models and use less membership queries. The first contribution is a survey over three algorithms for regular inference. We present their similarities and their differences in terms of the required number of membership queries. The second contribution is an investigation on how many membership queries a common regular inference algorithm, the L* algorithm by Angluin, requires for randomly generated DFAs and randomly generated DFAs with a structure common for communication protocol entities. In comparison, the DFAs with a structure common for communication protocol entities require more membership queries. The third contribution is an adaptation of regular inference to communication protocol entities which behavior foremost are affected by the message types. The adapted algorithm avoids asking membership queries containing messages with parameter values that results in already observed responses. The fourth contribution is an approach for regular inference of communication protocol entities which communicate with messages containing parameter values from very large ranges. The approach infers compact models, and uses parameter values taken from a small portion of their ranges in membership queries. The fifth contribution is an approach to infer compact models of communication protocol entities which have a similar partitioning of an entity's behavior into control states as in a designer's model of the protocol.

    List of papers
    1. Model Checking
    Open this publication in new window or tab >>Model Checking
    2005 (English)In: Model-Based Testing of Reactive Systems: Advanced Lectures, Berlin / Heidelberg: Springer , 2005, p. 557-603Chapter in book (Other academic)
    Place, publisher, year, edition, pages
    Berlin / Heidelberg: Springer, 2005
    Series
    Lecture Notes in Computer Sciences: Programming and Software Engineering, ISSN 0302-9743 ; 3472
    National Category
    Computer and Information Sciences
    Identifiers
    urn:nbn:se:uu:diva-98082 (URN)978-3-540-26278-7 (ISBN)
    Available from: 2009-02-06 Created: 2009-02-06 Last updated: 2018-01-13Bibliographically approved
    2. Insights to Angluin's Learning
    Open this publication in new window or tab >>Insights to Angluin's Learning
    2005 (English)In: Electronical Notes in Theoretical Computer Science, ISSN 1571-0661, E-ISSN 1571-0661, Vol. 118, p. 3-18Article in journal (Refereed) Published
    Abstract [en]

    Among other domains, learning finite-state machines is important for obtaining a model of a system under development, so that powerful formal methods such as model checking can be applied.

    A prominent algorithm for learning such devices was developed by Angluin. We have implemented this algorithm in a straightforward way to gain further insights to practical applicability. Furthermore, we have analyzed its performance on randomly generated as well as real-world examples. Our experiments focus on the impact of the alphabet size and the number of states on the needed number of membership queries. Additionally, we have implemented and analyzed an optimized version for learning prefix-closed regular languages. Memory consumption is one major obstacle when we attempted to learn large examples.

    We see that prefix-closed languages are relatively hard to learn compared to arbitrary regular languages. The optimization, however, shows positive results.

    Keywords
    deterministic finite-state automata, learning algorithm, regular languages, prefix-closed regular languages
    National Category
    Computer and Information Sciences
    Identifiers
    urn:nbn:se:uu:diva-98083 (URN)10.1016/j.entcs.2004.12.015 (DOI)
    Available from: 2009-02-06 Created: 2009-02-06 Last updated: 2018-01-13Bibliographically approved
    3. Regular Inference for State Machines with Parameters
    Open this publication in new window or tab >>Regular Inference for State Machines with Parameters
    2006 (English)In: Fundamental approaches to software engineering: ( 9th international conference, FASE 2006, held as part of the Joint European Conferences on Theory and Practice of Software, ETAPS 2006, Vienna, Austria, March 27-28, 2006 ), Berlin: Springer , 2006, p. 107-121Chapter in book (Other academic)
    Abstract [en]

    Techniques for inferring a regular language, in the form of a finite automaton, from a sufficiently large sample of accepted and nonaccepted input words, have been employed to construct models of software and hardware systems, for use, e.g., in test case generation. We intend to adapt these techniques to construct state machine models of entities of communication protocols. The alphabet of such state machines can be very large, since a symbol typically consists of a protocol data unit type with a number of parameters, each of which can assume many values. In typical algorithms for regular inference, the number of needed input words grows with the size of the alphabet and the size of the minimal DFA accepting the language. We therefore modify such an algorithm (Angluin's algorithm) so that its complexity grows not with the size of the alphabet, but only with the size of a certain symbolic representation of the DFA. The main new idea is to infer, for each state, a partitioning of input symbols into equivalence classes, under the hypothesis that all input symbols in an equivalence class have the same effect on the state machine. Whenever such a hypothesis is disproved, equivalence classes are refined. We show that our modification retains the good properties of Angluin's original algorithm, but that its complexity grows with the size of our symbolic DFA representation rather than with the size of the alphabet. We have implemented the algorithm; experiments on synthesized examples are consistent with these complexity results.

    Place, publisher, year, edition, pages
    Berlin: Springer, 2006
    Series
    Lecture notes in computer science, ISSN 0302-9743
    Keywords
    Test generation, Algorithm complexity, Modeling, Equivalence classes, Deterministic automaton, Data type, Transmission protocol, Finite automaton, Regular language, Inference, Software development
    National Category
    Computer and Information Sciences
    Identifiers
    urn:nbn:se:uu:diva-98084 (URN)3-540-33093-3 (ISBN)
    Available from: 2009-02-06 Created: 2009-02-06 Last updated: 2018-01-13Bibliographically approved
    4. Regular Inference for State Machines Using Domains with Equality Tests
    Open this publication in new window or tab >>Regular Inference for State Machines Using Domains with Equality Tests
    2008 (English)In: Fundamental Approaches to Software Engineering / [ed] Fiadeiro JL; Inverardi P, Berlin: Springer-Verlag , 2008, p. 317-331Conference paper, Published paper (Refereed)
    Abstract [en]

    Existing algorithms for regular inference (aka automata learning) allows to infer a finite state machine by observing the output that the machine produces in response to a selected sequence of input strings. We generalize regular inference techniques to infer a class of state machines with an infinite state space. We consider Mealy machines extended with state variables that can assume values from a potentially unbounded domain. These values can be passed as parameters in input and output symbols, and can be used in tests for equality between state variables and/or message parameters. This is to our knowledge the first extension of regular inference to infinite-state systems. We intend to use these techniques to generate models of communication protocols from observations of their input-output behavior. Such protocols often have parameters that represent node adresses, connection identifiers, etc. that have a large domain, and on which test for equality is the only meaningful operation. Our extension consists of two phases. In the first phase we apply an existing inference technique for finite-state Mealy machines to generate a model for the case that the values are taken from a small data domain. In the second phase we transform this finite-state Mealy machine into an infinite-state Mealy machine by folding it into a compact symbolic form.

    Place, publisher, year, edition, pages
    Berlin: Springer-Verlag, 2008
    Series
    Lecture Notes in Computer Science ; 4961
    National Category
    Computer Sciences
    Identifiers
    urn:nbn:se:uu:diva-98085 (URN)10.1007/978-3-540-78743-3_24 (DOI)000254603000024 ()978-3-540-78742-6 (ISBN)
    Conference
    11th International Conference on Fundamental Approaches to Software Engineering Budapest, HUNGARY, MAR 29-APR 06, 2008
    Available from: 2009-02-06 Created: 2009-02-06 Last updated: 2018-01-13Bibliographically approved
    5. Regular Inference for Communication Protocol Entities
    Open this publication in new window or tab >>Regular Inference for Communication Protocol Entities
    2008 (English)Report (Other academic)
    Series
    Technical report / Department of Information Technology, Uppsala University, ISSN 1404-3203 ; 2008-024
    Identifiers
    urn:nbn:se:uu:diva-98086 (URN)
    Available from: 2009-02-06 Created: 2009-02-06 Last updated: 2009-06-09Bibliographically approved
    Download full text (pdf)
    FULLTEXT02
  • 40. Bollig, Benedikt
    et al.
    Leucker, Martin
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology, Computer Systems. Datorteknik.
    Deciding LTL over Mazurkiewicz traces2003In: Data & Knowledge Engineering, ISSN 0169-023X, Vol. 44, no 2, p. 221-240Article in journal (Refereed)
  • 41. Bollig, Benedikt
    et al.
    Leucker, Martin
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology. Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Mathematics and Computer Science, Department of Information Technology, Computer Systems. Datorteknik.
    Model checking probabilistic distributed systems2003In: ASIAN 2003: Proceedings of the 8th Asian Computing Science Conference, 2003, p. 291-304Conference paper (Refereed)
  • 42.
    Bor, Martin
    et al.
    Lancaster University.
    Roedig, Utz
    Lancaster University.
    Voigt, Thiemo
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Architecture and Computer Communication.
    Alonso, Juan
    Univ. Nac. de Cuyo, Argentina.
    Do LoRa Low-Power Wide-Area Networks Scale?2016Conference paper (Refereed)
    Abstract [en]

    New Internet of Things (IoT) technologies such as LongRange (LoRa) are emerging which enable power ecientwireless communication over very long distances. Devicestypically communicate directly to a sink node which removesthe need of constructing and maintaining a complex multi-hop network. Given the fact that a wide area is coveredand that all devices communicate directly to a few sinknodes a large number of nodes have to share the commu-nication medium. LoRa provides for this reason a rangeof communication options (centre frequency, spreading fac-tor, bandwidth, coding rates) from which a transmitter canchoose. Many combination settings are orthogonal and pro-vide simultaneous collision free communications. Neverthe-less, there is a limit regarding the number of transmitters aLoRa system can support. In this paper we investigate thecapacity limits of LoRa networks. Using experiments wedevelop models describing LoRa communication behaviour.We use these models to parameterise a LoRa simulation tostudy scalability. Our experiments show that a typical smartcity deployment can support 120 nodes per 3.8 ha, which isnot sucient for future IoT deployments. LoRa networkscan scale quite well, however, if they use dynamic commu-nication parameter selection and/or multiple sinks.

    Download full text (pdf)
    fulltext
  • 43.
    Borgström, Gustaf
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Architecture and Computer Communication. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Rohner, Christian
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Architecture and Computer Communication. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Division of Computer Systems.
    Black-Schaffer, David
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Division of Computer Systems. Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Architecture and Computer Communication.
    Faster FunctionalWarming with Cache Merging2023In: PROCEEDINGS OF SYSTEM ENGINEERING FOR CONSTRAINED EMBEDDED SYSTEMS, DRONESE AND RAPIDO 2023, Association for Computing Machinery (ACM), 2023, p. 39-47Conference paper (Refereed)
    Abstract [en]

    Smarts-like sampled hardware simulation techniques achieve good accuracy by simulating many small portions of an application in detail. However, while this reduces the simulation time, it results in extensive cache warming times, as each of the many simulation points requires warming the whole memory hierarchy. Adaptive Cache Warming reduces this time by iteratively increasing warming to achieve sufficient accuracy. Unfortunately, each increases requires that the previous warming be redone, nearly doubling the total warming. We address re-warming by developing a technique to merge the cache states from the previous and additional warming iterations. We demonstrate our merging approach on multi-level LRU cache hierarchy and evaluate and address the introduced errors. Our experiments show that Cache Merging delivers an average speedup of 1.44x, 1.84x, and 1.87x for 128kB, 2MB, and 8MB L2 caches, respectively, (vs. a 2x theoretical maximum speedup) with 95-percentile absolute IPC errors of only 0.029, 0.015, and 0.006, respectively. These results demonstrate that Cache Merging yields significantly higher simulation speed with minimal losses.

  • 44.
    Borgström, Gustaf
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Architecture and Computer Communication.
    Sembrant, Andreas
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Architecture and Computer Communication.
    Black-Schaffer, David
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Architecture and Computer Communication.
    Adaptive cache warming for faster simulations2017In: Proc. 9th Workshop on Rapid Simulation and Performance Evaluation: Methods and Tools, New York: ACM Press, 2017, article id 1Conference paper (Refereed)
    Download full text (pdf)
    acw-rapido17-revision1
  • 45.
    Brundin, Michelle
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences.
    Morris, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences.
    Åhlman, Gustav
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences.
    Rosén, Emil
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences.
    Implementation av webbsida för rekommendationssystem med användaruppbyggd databas2012Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The goal of this project was to create a web-based, crowd-sourced, correlational database, that easily allowed users to submit objects and receive correlated objects as results. The webservice was created in the web development languages of HTML, CSS, PHP and Javscript, with MySQL to handle the database. Simultaneous development was kept in check with the aid of the source code management system GIT. Upon completion, the service contained several HTML-views, the ability to add and rate objects, a per-object dedicated page with information parsed from Wikipedia.org, and a view with objects ranked in accordance to the preferences specific to the current user. Roughly a month after the beginning of development, the website was publicly launched and promoted in order to collect data, and improvements were added to the website as needed. Two weeks after the public launch, the collected data was measured and analyzed. The algorithm proved effective and scalable, especially with the introduction of tags and simultaneous computation of object features.

    Download full text (pdf)
    Implementation av webbsida för rekommendationssystem med användaruppbyggd databas
  • 46.
    Bull, Victoria
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Systems.
    Intrusion Detection in the Internet of Things: From Sniffing to a Border Router’s Point of View2023Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The Internet of Things is expanding, and with the increasing numbers of connected devices,exploitation of those devices also becomes more common. Since IoT devices and IoT networksare used in many crucial areas in modern societies, ranging from everything between securityand militrary applications to healthcare monitoring and production efficiency, the need to securethese devices is of great importance for researchers and businesses. This project explores howan intrusion detection system called DETONAR can be used on border router logs, instead of itsoriginal use of sniffer devices. Using DETONAR in this way allows us to detect many differentattacks, without contributing to the additional cost of deploying sniffer devices and the additionalrisk of the sniffer devices themselves becoming the target of attack

    Download full text (pdf)
    fulltext
  • 47.
    Bytyqi, Meriton
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology.
    Creating a graphical user interface for cross-platform devices with a user-centered agile process2022Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    PC-Dart is a software that the Swedish Armed Forces use to communicate when active on the field. They are limited to using the program only on Windows operating system, and their devices are not suitable for challenging contexts. It is not convenient for the army to bring impractical devices to the field, and it requires the soldiers to bring sleds of batteries and charging equipment with them. This thesis explores the possibilities of recreating the graphical user interface onto other platforms such as Android and Linux. It helps to increase the mobility on the field for the troops of the Swedish Armed Forces, which also means that there is not any restrictions by using their program on one platform. The development of the program required a pilot study on what available cross-platform frameworks to use in terms of developing an application that works on multiple platforms. Together with a relevant framework and a custom user-centered agile work process, this thesis strives to create an application that is cross-platform and with a graphical user interface that old users of the previous program can relate to. The project results show that a graphical user interface can be developed with a cross-platform framework while working in a user-centered agile process. However, it also shows that it can be a lot of work for one person, negatively affecting the process.

    Download full text (pdf)
    fulltext
  • 48. Cao, B.
    et al.
    Fu, Y.
    Sun, Z.
    Liu, X.
    He, H.
    Lv, Zhihan
    Uppsala University, Disciplinary Domain of Humanities and Social Sciences, Faculty of Arts, Department of Game Design.
    A Resource Allocation Strategy in Fog-Cloud Computing Towards the Internet of Things in the 5G Era2021Conference paper (Refereed)
    Abstract [en]

    The rapid development of Internet of Things (IoTs) will result in massive amounts of data to be processed. The 5G technology and fog computing can reduce the service delay. A challenging problem in fog computing is how to efficiently allocate resources to guarantee the quality of service (QoS). Therefore, studying the cooperation between fog computing resources and cloud computing resources is of great significance. For resource allocation, four optimization objectives are considered: Minimizing the time delay and cost and maximizing the load balancing and stability of task execution, and an improved Two_Archive2 algorithm using a novel fitness evaluation method and a shift-based density estimation strategy (SDE) is proposed. For the case of resource allocation in fog-cloud computing, the proposed algorithm shows the better performance than the state-of-the-art algorithms and could serve as an effective resource allocation scheme. © 2021 IEEE.

  • 49.
    Carbone, Marco
    et al.
    IT Univ Copenhagen, Rued Langgaards Vej 7, DK-2300 Copenhagen, Denmark..
    Hildebrandt, Thomas
    IT Univ Copenhagen, Rued Langgaards Vej 7, DK-2300 Copenhagen, Denmark..
    Parrow, Joachim
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computing Science.
    Weidlich, Matthias
    Humboldt Univ, Unter Linden 6, D-10099 Berlin, Germany..
    Extended versions of papers presented at WS-FM 2014 and Beat 20142016In: Formal Aspects of Computing, ISSN 0934-5043, E-ISSN 1433-299X, Vol. 28, no 4, p. 529-530Article in journal (Other academic)
  • 50.
    Carlos, Pérez-Penichet
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Architecture and Computer Communication.
    Noda, Claro
    Mid-Sweden University, Sweden.
    Varshney, Ambuj
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Architecture and Computer Communication.
    Voigt, Thiemo
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computer Architecture and Computer Communication.
    Battery-free 802.15. 4 Receiver2018In: 17th ACM/IEEE International Conference on Information Processing in Sensor Networks (IPSN), IEEE, 2018Conference paper (Refereed)
    Abstract [en]

    We present the architecture of an 802.15.4 receiver that, for the first time, operates at a few hundred microwatts, enabling new battery-free applications. To reach the required micro-power consumption, the architecture diverges from that of commodity receivers in two important ways. First, it offloads the power-hungry local oscillator to an external device, much like backscatter transmitters do. Second, we avoid the energy cost of demodulating a phase-modulated signal by treating 802.15.4 as a frequency-modulated one, which allows us to receive with a simple passive detector and an energy-efficient thresholding circuit. We describe a prototype that can receive 802.15.4 frames with a power consumption of 361 μW. Our receiver prototype achieves sufficient communication range to integrate with deployed wireless sensor networks (WSNs). We illustrate this integration by pairing the prototype with an 802.15.4 backscatter transmitter and integrating it with unmodified 802.15.4 sensor nodes running the TSCH and Glossy protocols.

1234567 1 - 50 of 440
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf