Change search
Refine search result
1234567 1 - 50 of 3276
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • 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)
  • 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)
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.
    Abbas, Nadeem
    et al.
    EcoFES.
    Andersson, Jesper
    EcoFES.
    Architectural Reasoning Support for Product-Lines of Self-adaptive Software Systems - A Case Study2015In: Software Architecture: 9th European Conference, ECSA 2015, Dubrovnik/Cavtat, Croatia, September 7-11, 2015. Proceedings, Springer International Publishing , 2015, 17, 20-36 p.Chapter in book (Refereed)
    Abstract [en]

    Software architecture serves as a foundation for the design and development of software systems. Designing an architecture requires extensive analysis and reasoning. The study presented herein focuses on the architectural analysis and reasoning in support of engineering self-adaptive software systems with systematic reuse. Designing self-adaptive software systems with systematic reuse introduces variability along three dimensions; adding more complexity to the architectural analysis and reasoning process. To this end, the study presents an extended Architectural Reasoning Framework with dedicated reasoning support for self-adaptive systems and reuse. To evaluate the proposed framework, we conducted an initial feasibility case study, which concludes that the proposed framework assists the domain architects to increase reusability, reduce fault density, and eliminate differences in skills and experiences among architects, which were our research goals and are decisive factors for a system’s overall quality.

  • 2.
    Abbas, Nadeem
    et al.
    RISE, Swedish ICT, SICS, Software and Systems Engineering Laboratory. Linnaeus University.
    Andersson, Jesper
    RISE, Swedish ICT, SICS, Software and Systems Engineering Laboratory. Linnaeus University.
    Harnessing Variability in Product-lines of Self-adaptive Software Systems2015Conference paper (Refereed)
    Abstract [en]

    This work studies systematic reuse in the context of self-adaptive software systems. In our work, we realized that managing variability for such platforms is different compared to traditional platforms, primarily due to the run-time variability and system uncertainties. Motivated by the fact that recent trends show that self-adaptation will be used more often in future system generation and that software reuse state-of-practice or research do not provide sufficient support, we have investigated the problems and possibly resolutions in this context. We have analyzed variability for these systems, using a systematic reuse prism, and identified a research gap in variability management. The analysis divides variability handling into four activities: (1) identify variability, (2) constrain variability, (3) implement variability, and (4) manage variability. Based on the findings we envision a reuse framework for the specific domain and present an example framework that addresses some of the identified challenges. We argue that it provides basic support for engineering self-adaptive software systems with systematic reuse. We discuss some important avenues of research for achieving the vision.

  • 3. Abbaspour Assadollah, Sara
    et al.
    Saadatmand, Mehrdad
    RISE - Research Institutes of Sweden, ICT, SICS.
    Sundmark, Daniel
    Hansson, Hans
    A Model for Systematic Monitoring and Debugging of Starvation Bugs in Multicore Software2016Conference paper (Refereed)
    Abstract [en]

    With the development of multicore hardware, concurrent, parallel and multicore software are becoming increasingly popular. Software companies are spending a huge amount of time and resources to nd and debug the bugs. Among all types of software bugs, concurrency bugs are also important and troublesome. This type of bugs is increasingly becoming an issue particularly due to the growing prevalence of multicore hardware. In this position paper, we propose a model for monitoring and debugging Starvation bugs as a type of concurrency bugs in multicore software. The model is composed into three phases: monitoring, detecting and debugging. The monitoring phase can support detecting phase by storing collected data from the system execution. The detecting phase can support debugging phase by comparing the stored data with starvation bug's properties, and the debugging phase can help in reproducing and removing the Starvation bug from multicore software. Our intention is that our model is the basis for developing tool(s) to enable solving Starvation bugs in software for multicore platforms.

  • 4.
    Abdelraheem, Mohamed Ahmed
    et al.
    RISE, Swedish ICT, SICS.
    Alizadeh, Javad
    Alkhzaimi, Hoda A.
    Aref, Mohammad Reza
    Bagheri, Nasour
    Gauravaram, Praveen
    Improved Linear Cryptanalysis of reduced-round SIMON-32 and SIMON-482015Conference paper (Refereed)
    Abstract [en]

    In this paper we analyse two variants of SIMON family of light-weight block ciphers against linear cryptanalysis and present the best linear cryptanalytic results on these variants of reduced-round SIMON to date. We propose a time-memory trade-off method that finds differential/linear trails for any permutation allowing low Hamming weight differential/linear trails. Our method combines low Hamming weight trails found by the correlation matrix representing the target permutation with heavy Hamming weight trails found using a Mixed Integer Programming model representing the target differential/linear trail. Our method enables us to find a 17-round linear approximation for SIMON-48 which is the best current linear approximation for SIMON-48. Using only the correlation matrix method, we are able to find a 14-round linear approximation for SIMON-32 which is also the current best linear approximation for SIMON-32. The presented linear approximations allow us to mount a 23-round key recovery attack on SIMON-32 and a 24-round Key recovery attack on SIMON-48/96 which are the current best results on SIMON-32 and SIMON-48. In addition we have an attack on 24 rounds of SIMON-32 with marginal complexity.

  • 5.
    Abdelraheem, Mohammed Ahmed
    et al.
    RISE, Swedish ICT, SICS, Security Lab.
    Gehrmann, Christian
    RISE, Swedish ICT, SICS, Security Lab.
    Lindström, Malin
    Nordahl, Christian
    Executing Boolean Queries on an EncryptedBitmap Index2016Conference paper (Refereed)
    Abstract [en]

    We propose a simple and efficient searchable symmetric

    encryption scheme based on a Bitmap index that evaluates

    Boolean queries. Our scheme provides a practical

    solution in settings where communications and computations

    are very constrained as it offers a suitable tradeoff

    between privacy and performance.

  • 6. 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.

  • 7.
    Abrahamsson, Henrik
    RISE, Swedish ICT, SICS. School of Innovation, Design and Engineering.
    Network overload avoidance by traffic engineering and content caching2012Doctoral thesis, monograph (Other academic)
    Abstract [en]

    The Internet traffic volume continues to grow at a great rate, now driven by video and TV distribution. For network operators it is important to avoid congestion in the network, and to meet service level agreements with their customers. This thesis presents work on two methods operators can use to reduce links loads in their networks: traffic engineering and content caching. This thesis studies access patterns for TV and video and the potential for caching. The investigation is done both using simulation and by analysis of logs from a large TV-on-Demand system over four months. The results show that there is a small set of programs that account for a large fraction of the requests and that a comparatively small local cache can be used to significantly reduce the peak link loads during prime time. The investigation also demonstrates how the popularity of programs changes over time and shows that the access pattern in a TV-on-Demand system very much depends on the content type. For traffic engineering the objective is to avoid congestion in the network and to make better use of available resources by adapting the routing to the current traffic situation. The main challenge for traffic engineering in IP networks is to cope with the dynamics of Internet traffic demands. This thesis proposes L-balanced routings that route the traffic on the shortest paths possible but make sure that no link is utilised to more than a given level L. L-balanced routing gives efficient routing of traffic and controlled spare capacity to handle unpredictable changes in traffic. We present an L-balanced routing algorithm and a heuristic search method for finding L-balanced weight settings for the legacy routing protocols OSPF and IS-IS. We show that the search and the resulting weight settings work well in real network scenarios.

  • 8.
    Abrahamsson, Henrik
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Traffic measurement and analysis1999Report (Other academic)
    Abstract [en]

    Measurement and analysis of real traffic is important to gain knowledge about the characteristics of the traffic. Without measurement, it is impossible to build realistic traffic models. It is recent that data traffic was found to have self-similar properties. In this thesis work traffic captured on the network at SICS and on the Supernet, is shown to have this fractal-like behaviour. The traffic is also examined with respect to which protocols and packet sizes are present and in what proportions. In the SICS trace most packets are small, TCP is shown to be the predominant transport protocol and NNTP the most common application. In contrast to this, large UDP packets sent between not well-known ports dominates the Supernet traffic. Finally, characteristics of the client side of the WWW traffic are examined more closely. In order to extract useful information from the packet trace, web browsers use of TCP and HTTP is investigated including new features in HTTP/1.1 such as persistent connections and pipelining. Empirical probability distributions are derived describing session lengths, time between user clicks and the amount of data transferred due to a single user click. These probability distributions make up a simple model of WWW-sessions.

  • 9.
    Abrahamsson, Henrik
    et al.
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Ahlgren, Bengt
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Temporal Characteristics of Large IP Traffic Flows2003Report (Other academic)
    Abstract [en]

    Several studies of Internet traffic have shown that it is a small percentage of the flows that dominate the traffic. This is often referred to as the mice and elephants phenomenon. It has been proposed that this might be one of very few invariants of Internet traffic and that this property could somehow be used for traffic engineering purposes. The idea being that one in a scalable way could control a major part of the traffic by only keeping track of a small number of flows. But for this the large flows must also be stable in the meaning that they should be among the largest flows during long periods of time. In this work we analyse packet traces of Internet traffic and study the temporal characteristics of large aggregated traffic flows defined by destination address prefixes.

  • 10.
    Abrahamsson, Henrik
    et al.
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Ahlgren, Bengt
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Using empirical distributions to characterize web client traffic and to generate synthetic traffic2000Conference paper (Refereed)
  • 11.
    Abrahamsson, Henrik
    et al.
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Ahlgren, Bengt
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Alonso, Juan
    RISE - Research Institutes of Sweden, ICT, SICS.
    Andersson, Anders
    RISE - Research Institutes of Sweden, ICT, SICS.
    Kreuger, Per
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    A Multi Path Routing Algorithm for IP Networks Based on Flow Optimisation.2002Conference paper (Refereed)
  • 12.
    Abrahamsson, Henrik
    et al.
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Ahlgren, Bengt
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Alonso, Juan
    RISE - Research Institutes of Sweden, ICT, SICS.
    Andersson, Anders
    RISE - Research Institutes of Sweden, ICT, SICS.
    Kreuger, Per
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    From QoS provisioning to QoS charging2002In: Proceedings of the Second International Workshop on Internet Charging and QoS Technologies, ICQT 2002, 2002, 1, Vol. Lectures Notes in Computer Science (LNCS) no. 2511, 135-144 p.Conference paper (Refereed)
  • 13.
    Abrahamsson, Henrik
    et al.
    RISE - Research Institutes of Sweden, ICT, SICS.
    Ahlgren, Bengt
    RISE - Research Institutes of Sweden, ICT, SICS.
    Lindvall, Patrik
    TeliaSonera, Sweden.
    Nieminen, Johanna
    TeliaSonera, Sweden.
    Tholin, Per
    TeliaSonera, Sweden.
    Traffic Characteristics on 1Gbit/s Access Aggregation Links2017Conference paper (Refereed)
    Abstract [en]

    Large network operators have thousands or tens of thousands of access aggregation links that they need to manage and dimension properly. Measuring and understanding the traffic characteristics on these type of links are therefore essential. What do the traffic intensity characteristics look like on different timescales from days down to milliseconds? How do the characteristics differ if we compare links with the same capacity but with different type of clients and access technologies? How do the traffic characteristics differ from that on core network links? These are the type of questions we set out to investigate in this paper. We present the results of packet level measurements on three different 1Gbit/s aggregation links in an operational IP network. We see large differences in traffic characteristics between the three links. We observe highly skewed link load probability densities on timescales relevant for buffering (i.e. 10-milliseconds). We demonstrate the existence of large traffic spikes on short timescales (10-100ms) and show their impact on link delay. We also found that these traffic bursts often are caused by only one or a few IP flows.

  • 14.
    Abrahamsson, Henrik
    et al.
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Ahlgren, Bengt
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Tholin, Per
    Delay and Traffic Intensity Monitoring in an Operational IP Network2015Conference paper (Refereed)
  • 15.
    Abrahamsson, Henrik
    et al.
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Björkman, Mats
    Caching for IPTV distribution with time-shift2013Conference paper (Refereed)
  • 16.
    Abrahamsson, Henrik
    et al.
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Björkman, Mats
    Robust Traffic Engineering using L-balanced Weight-Settings in OSPF/IS-IS2009Conference paper (Refereed)
  • 17.
    Abrahamsson, Henrik
    et al.
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Björkman, Mats
    Simulation of IPTV caching strategies2010Conference paper (Refereed)
    Abstract [en]

    IPTV, where television is distributed over the Internet Protocol in a single operator network, has become popular and widespread. Many telecom and broadband companies have become TV providers and distribute TV channels using multicast over their backbone networks. IPTV also means an evolution to time-shifted television where viewers now often can choose to watch the programs at any time. However, distributing individual TV streams to each viewer requires a lot of bandwidth and is a big challenge for TV operators. In this paper we present an empirical IPTV workload model, simulate IPTV distribution with time-shift, and show that local caching can limit the bandwidth requirements significantly.

  • 18.
    Abrahamsson, Henrik
    et al.
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Gunnar, Anders
    RISE, Swedish ICT, SICS.
    Traffic engineering in ambient networks: challenges and approaches2004In: Swedish National Computer Networking Workshop, 2004, 1Conference paper (Refereed)
    Abstract [en]

    The focus of this paper is on traffic engineering in ambient networks. We describe and categorize different alternatives for making the routing more adaptive to the current traffic situation and discuss the challenges that ambient networks pose on traffic engineering methods. One of the main objectives of traffic engineering is to avoid congestion by controlling and optimising the routing function, or in short, to put the traffic where the capacity is. The main challenge for traffic engineering in ambient networks is to cope with the dynamics of both topology and traffic demands. Mechanisms are needed that can handle traffic load dynamics in scenarios with sudden changes in traffic demand and dynamically distribute traffic to benefit from available resources. Trade-offs between optimality, stability and signaling overhead that are important for traffic engineering methods in the fixed Internet becomes even more critical in a dynamic ambient environment.

  • 19.
    Abrahamsson, Henrik
    et al.
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Hagsand, Olof
    Marsh, Ian
    RISE - Research Institutes of Sweden, ICT, SICS.
    TCP over High Speed Variable Capacity Links: A Simulation Study for Bandwidth Allocation2002Conference paper (Refereed)
  • 20.
    Abrahamsson, Henrik
    et al.
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Kreuger, Per
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    A case for resource management in IPTV distribution2008Conference paper (Refereed)
  • 21.
    Abrahamsson, Henrik
    et al.
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Kreuger, Per
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Resource Management for IPTV distribution2009In: ERCIM News, Vol. 77Article in journal (Other academic)
  • 22.
    Abrahamsson, Henrik
    et al.
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Marsh, Ian
    RISE - Research Institutes of Sweden, ICT, SICS.
    DTMsim - DTM channel simulation in ns2001Report (Other academic)
    Abstract [en]

    Dynamic Transfer Mode (DTM) is a ring based MAN technology that provides a channel abstraction with a dynamically adjustable capacity. TCP is a reliable end to end transport protocol capable of adjusting its rate. The primary goal of this work is investigate the coupling of dynamically allocating bandwidth to TCP flows with the affect this has on the congestion control mechanism of TCP. In particular we wanted to find scenerios where this scheme does not work, where either all the link capacity is allocated to TCP or congestion collapse occurs and no capacity is allocated to TCP. We have created a simulation environment using ns-2 to investigate TCP over networks which have a variable capacity link. We begin with a single TCP Tahoe flow over a fixed bandwidth link and progressively add more complexity to understand the behaviour of dynamically adjusting link capacity to TCP and vice versa.

  • 23.
    Abrahamsson, Henrik
    et al.
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Nordmark, Mattias
    Program Popularity and Viewer Behaviour in a Large TV-on-Demand System2012Conference paper (Refereed)
  • 24. Adawi, T.
    et al.
    Burden, Håkan
    RISE, Swedish ICT, Viktoria.
    Olsson, D.
    Mattiasson, R.
    zCharacterizing Software Engineering Students' Discussions during Peer Instruction: Opportunities for Learning and Implications for Teaching2016In: International Journal of Engineering ,Science and Innovative Technology, ISSN 0949-149X, E-ISSN 2277-3754, Vol. 32, no 2B, 927-936 p.Article in journal (Refereed)
    Abstract [en]

    Peer instruction is a method for activating students during lectures, which has gained a considerable amount of attention in higher education due to claims of dramatic improvement in learning gains. The purpose of this qualitative research study is to investigate what types of discussions engineering students engage in during a peer instruction session and what learning possibilities that are enabled by these different types of discussions. We observed twelve students during six separate and simulated peer instruction sessions and the students were interviewed individually after the sessions.Ananalysis of the data revealed that the students engaged in three qualitatively different types of discussions: affirmative discussions, motivating discussions, and argumentative discussions. We characterize these different types of discussions in terms of the number of alternative answers the students discuss, the extent to which they draw on prior knowledge and experiences, as well as the fundamental difference between an explanation and an argument. A good opportunity for learning is opened up when students are aspiring to find the truth, not simply being satisfied with what they believe to be true. We conclude that students do not always engage in discussions that support their learning in the best way, and we discuss implications for using peer instruction as a teaching method. © 2016 TEMPUS Publications.

  • 25. Adler, Daniel
    Virtual Audio - Three-Dimensional Audio in Virtual Environments1996Report (Refereed)
    Abstract [en]

    Three-dimensional interactive audio has a variety ofpotential uses in human-machine interfaces. After lagging seriously behind the visual components, the importance of sound is now becoming increas-ingly accepted. This paper mainly discusses background and techniques to implement three-dimensional audio in computer interfaces. A case study of a system for three-dimensional audio, implemented by the author, is described in great detail. The audio system was moreover integrated with a virtual reality system and conclusions on user tests and use of the audio system is presented along with proposals for future work at the end of the paper. The thesis begins with a definition of three-dimensional audio and a survey on the human auditory system to give the reader the needed knowledge of what three-dimensional audio is and how human auditory perception works.

  • 26. Afrasiabi, R.
    et al.
    Soderberg, L. M.
    Joensson, H. N.
    Björk, Per
    RISE, Swedish ICT, Acreo.
    Svahn, H. A.
    Linnros, J.
    Integration of a droplet-based microfluidic system and silicon nanoribbon FET sensor2016In: Micromachines, ISSN 2072-666X, E-ISSN 2072-666X, Vol. 7, no 8, 134Article in journal (Refereed)
    Abstract [en]

    We present a novel microfluidic system that integrates droplet microfluidics with a silicon nanoribbon field-effect transistor (SiNR FET), and utilize this integrated system to sense differences in pH. The device allows for selective droplet transfer to a continuous water phase, actuated by dielectrophoresis, and subsequent detection of the pH level in the retrieved droplets by SiNR FETs on an electrical sensor chip. The integrated microfluidic system demonstrates a label-free detection method for droplet microfluidics, presenting an alternative to optical fluorescence detection. In this work, we were able to differentiate between droplet trains of one pH-unit difference. The pH-based detection method in our integrated system has the potential to be utilized in the detection of biochemical reactions that induce a pH-shift in the droplets.

  • 27. Africano, Diana
    et al.
    Clark, Brendon
    RISE, Swedish ICT, Interactive Institute. Design Research Unit.
    Design för kulturell mångfald2006In: Västerbotten (Umeå. 1920), Västerbotten (Umeå. 1920) , 2006, 10, 36-39 p.Chapter in book (Other academic)
  • 28. Aggoun, Abderrahmane
    et al.
    Beldiceanu, Nicolas
    Carlsson, Mats
    RISE, Swedish ICT, SICS. Computer Systems Laboratory.
    Fages, François
    Integrating rule-based modelling and constraint programming for solving industrial packing problems2010In: ERCIM News, ISSN 0926-4981, E-ISSN 1564-0094, 34-35 p.Article in journal (Refereed)
    Abstract [en]

    Packing items in bins is an old but nevertheless challenging combinatorial problem with numerous applications in industry. We report on an original approach based on constraint programming and rule-based modelling, which has been investigated in the framework of the FP6 ‘specific targeted research project’ Net-WMS (Towards integrating virtual reality and optimization techniques in a new generation of Networked businesses in Warehouse Management Systems under constraints). It has applications in the automotive industry.

  • 29.
    Ahlgren, Bengt
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    A host interface to the DTM high speed network1992Conference paper (Refereed)
  • 30.
    Ahlgren, Bengt
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    A performance model for integrated layer processing1997Conference paper (Refereed)
    Abstract [en]

    Integrated Layer Processing is an implementation technique for data manipulation functions in communication protocols. The purpose of this technique is to increase communication performance. It reduces the number of memory accesses and thus relieves the memory bandwidth bottleneck. Integrated Layer Processing can however, in some situations, substantially increase the number of memory accesses, and therefore instead reduce performance. The main reason is contention for processor registers. We present a performance model that captures the memory behavior of data manipulation functions for both integrated and sequential implementations. By comparing the model to measurements of real and synthetic data manipulation functions, we show that the model accurately predicts the performance. The model can be used to assess whether an integrated implementation will perform better or worse than a sequential implementation. The situations where integration would reduce performance can then be avoided without spending a lot of effort on a more complex integrated implementation.

  • 31.
    Ahlgren, Bengt
    RISE - Research Institutes of Sweden, ICT, SICS.
    Improving computer communication performance by reducing memory bandwidth consumption1997Doctoral thesis, monograph (Other academic)
  • 32.
    Ahlgren, Bengt
    RISE, Swedish ICT, SICS. Decisions, Networks and Analytics lab.
    NetInf Routing Using Hints2013Conference paper (Refereed)
    Abstract [en]

    We define a global routing mechanism for the NetInf protocol, part of the NetInf information-centric networking architecture. The mechanism makes use of two levels of aggregation in order to provide the scalability needed for a global network. An anticipated $10^{15}$ number of individual named data objects are aggregated to in the order of 500K routing hints which are very feasible to handle with existing routing technology. The hints are then used to forward requests for named data towards the publisher.

  • 33.
    Ahlgren, Bengt
    et al.
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Andersson, Anders
    Hagsand, Olof
    Marsh, Ian
    RISE - Research Institutes of Sweden, ICT, SICS.
    Dimensioning Links for IP Telephony2000Report (Refereed)
    Abstract [en]

    Transmitting telephone calls over the Internet causes problems not present in current telephone technology such as packet loss and delay due to queueing in routers. In this undergraduate thesis we study how a Markov modulated Poisson process is applied as an arrival process to a multiplexer and we study the performance in terms of loss probability. The input consists of the superposition of independent voice sources. The predictions of the model is compared with results obtained with simulations of the multiplexer made with a network simulator. The buffer occupancy distribution is also studied and we see how this distribution changes as the load increases.

  • 34.
    Ahlgren, Bengt
    et al.
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Andersson, Anders
    Hagsand, Olof
    RISE - Research Institutes of Sweden, ICT, SICS.
    Marsh, Ian
    RISE - Research Institutes of Sweden, ICT, SICS.
    Dimensioning links for IP telephony2001In: Proceedings of the 2nd IP-Telephony Workshop (IPtel 2001), 2-3 April 2001, New York City, New York, USA, 2001, 1Conference paper (Refereed)
    Abstract [en]

    Packet loss is an important parameter for dimensioning network links or traffic classes carrying IP telephony traffic. We present a model based on the Markov modulated Poisson process (MMPP) which calculates packet loss probabilities for a set of super positioned voice input sources and the specified link properties. We do not introduce another new model to the community, rather try and verify one of the existing models via extensive simulation and a real world implementation. A plethora of excellent research on queuing theory is still in the domain of ATM researchers and we attempt to highlight its validity to the IP Telephony community. Packet level simulations show very good correspondence with the predictions of the model. Our main contribution is the verification of the MMPP model with measurements in a laboratory environment. The loss rates predicted by the model are in general close to the measured loss rates and the loss rates obtained with simulation. The general conclusion is that the MMPP-based model is a tool well suited for dimensioning links carrying packetized voice in a system with limited buffer space.

  • 35.
    Ahlgren, Bengt
    et al.
    RISE, Swedish ICT, SICS. NETS.
    Aranda, Pedro A.
    SAIL.
    Chemouil, Prosper
    SAIL.
    Correia, Luis M.
    SAIL.
    Holger, Karl
    SAIL.
    Oueslati, Sara
    SAIL.
    Söllner, Michael
    SAIL.
    Welin, Annikki
    SAIL.
    Content, Connectivity and Cloud: Ingredients for the Network of the Future2011In: IEEE Communications Magazine, ISSN 0163-6804, E-ISSN 1558-1896, Vol. 49, 62-70 p.Article in journal (Refereed)
    Abstract [en]

    A new network architecture for the Internet needs ingredients from three approaches: information-centric networking, cloud computing integrated with networking, and open connectivity. Information-centric networking considers pieces of information as first-class entities of a networking architecture, rather than only indirectly identifying and manipulating them via a node hosting that information; this way, information becomes independent from the devices they are stored in, enabling efficient and application-independent information caching in the network. Cloud networking offers a combination and integration of cloud computing and virtual networking. It is a solution that distributes the benefits of cloud computing more deeply into the network, and provides a tighter integration of virtualisation features at computing and networking levels. To support these concepts, open connectivity services need to provide advanced transport and networking mechanisms, making use of network and path diversity (even leveraging direct optical paths) and encoding techniques, and dealing with ubiquitous mobility of user, content and information objects in a unified way.

  • 36. Ahlgren, Bengt
    et al.
    Björkman, Mats
    Multimedia transport service and protocol issues1992Report (Refereed)
    Abstract [en]

    This paper considers the issues of a real time transport service needed by multimedia applications for transferring digital video and audio. Three classes of transport service are defined with different levels of real time constraints. Methods for error control are considered for the classes, and the classes are discussed with respect to the application requirements.

  • 37.
    Ahlgren, Bengt
    et al.
    RISE - Research Institutes of Sweden, ICT, SICS.
    Björkman, Mats
    Gunningberg, Per
    Integrated layer processing can be hazardous to your performance1997Conference paper (Refereed)
    Abstract [en]

    Integrated Layer Processing (ILP) has been presented as an implementation technique to improve communication protocol performance by reducing the number of memory references. Previous research has however not pointed out that in some circumstances ILP can significantly increase the number of memory references, resulting in lower communication throughput. We explore the performance effects of applying ILP to data manipulation functions with varying characteristics. The functions are generated from a set of parameters including input and output block size, state size and number of instructions. We present experimental data for varying function state sizes, number of integrated functions and instruction counts. The results clearly show that the aggregated state of the functions must fit in registers for ILP to be competitive.

  • 38.
    Ahlgren, Bengt
    et al.
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Björkman, Mats
    Gunningberg, Per
    RISE - Research Institutes of Sweden, ICT, SICS.
    The applicability of integrated layer processing1998In: IEEE Journal on Selected Areas in Communications, Vol. 16, no 3, 317-331 p.Article in journal (Refereed)
    Abstract [en]

    In this paper we review previous work on the applicability and performance of Integrated Layer Processing (ILP). ILP has been shown to clearly improve computer communication performance when integrating simple data manipulation functions, but the situation has been less clear for more complex functions and complete systems. We discuss complications when applying ILP to protocol stacks, the requirements of ILP on the communication subsystem, caching aspects, the importance of the processor registers, and a model for predicting the performance of data manipulation functions. We conclude that the main drawback of ILP is its limited aplicability to complex data manipulation functions. The performance to expect from an ILP implementation also depends heavily on the protocol architecture and the host system architecture.

  • 39.
    Ahlgren, Bengt
    et al.
    RISE - Research Institutes of Sweden, ICT, SICS.
    Björkman, Mats
    Gunningberg, Per
    RISE - Research Institutes of Sweden, ICT, SICS.
    Towards predictable ILP performance-controlling communication buffer cache effects1995Conference paper (Refereed)
  • 40.
    Ahlgren, Bengt
    et al.
    RISE, Swedish ICT, SICS. CNA.
    Björkman, Mats
    Gunningberg, Per
    Towards predictable ILP performance-controlling communication buffer cache effects1996In: The Australian Computer Journal, Vol. 28, 66-71 p.Article in journal (Refereed)
    Abstract [en]

    Cache memory behavior is becoming more and more important as the speed of CPUs is increasing faster than the speed of memories. The operation of caches are statistical which means that the system level performance becomes unpredictable. In this paper we investigate the worst case behavior of cache line conflicts in the context of communication protocols implemented using Integrated Layer Processing. The goal of our work is to control the cache by placing communication buffers and code in non-conflicting positions in the cache. The result would be higher and more predictable performance. Our first results indicate that the worst case behavior can be up to almost four times slower than the best case.

  • 41.
    Ahlgren, Bengt
    et al.
    RISE - Research Institutes of Sweden, ICT, SICS.
    Björkman, Mats
    Moldeklev, Kjersti
    The performance of a no-copy API for communication1995Conference paper (Refereed)
    Abstract [en]

    We present a so-called no-copy Application Programming Interface (API) for communication. The interface avoids copying when data is transferred between the application and operating system kernel address spaces. The API is an extension to the socket interface for SunOS, and has been implemented on Sun SPARCstations equipped with Fore Systems ATM adapters. Throughput for the no-copy API is 85 Mbit/s for 8K UDP messages, to be compared to 57 Mbit/s for the regular API on the SPARCstation 2. Processing times through the TCP and UDP stacks are reduced by up to 30% for the SPARCstation 2 and by more than 50% for the SPARCstation 10.

  • 42.
    Ahlgren, Bengt
    et al.
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Brunner, Marcus
    Eggert, Lars
    Hancock, Robert
    Schmid, Stefan
    Invariants: A New Design Methodology for Network Architectures2004Conference paper (Refereed)
    Abstract [en]

    The first age of Internet architectural thinking concentrated on defining the correct principles for designing a packet-switched network and its application protocol suites. Although these same principles remain valid today, they do not address the question of how to reason about the evolution of the Internet or its interworking with other networks of very different heritages. This paper proposes a complementary methodology, motivated by the view that evolution and interworking flexibility are determined not so much by the principles applied during initial design, but by the choice of fundamental components or "design invariants" in terms of which the design is expressed. The paper discusses the characteristics of such invariants, including examples from the Internet and other networks, and considers what attributes of invariants best support architectural flexibility.

  • 43.
    Ahlgren, Bengt
    et al.
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    D’Ambrosio, Matteo
    4WARD.
    Dannewitz, Christian
    4WARD.
    Marchisio, Marco
    4WARD.
    Marsh, Ian
    RISE - Research Institutes of Sweden, ICT, SICS.
    Ohlman, Börje
    4WARD.
    Pentikousis, Kostas
    4WARD.
    Rembarz, René
    4WARD.
    Strandberg, Ove
    4WARD.
    Vercellone, Vinicio
    4WARD.
    Design considerations for a network of information2008Conference paper (Refereed)
    Abstract [en]

    The existing Internet ecosystem is a result of decades of evolution. It has managed to scale well beyond the original aspirations. Evolution, though, highlighted a certain degree of inadequacies that is well documented. In this position paper we present the design considerations for a re-architected global networking architecture which delivers dissemination and non-dissemination objects only to consenting recipients, reducing unwanted traffic, linking information producers with consumers independently of the hosts involved, and connects the digital with the physical world. We consider issues ranging from the proposed object identifier/locator split to security and trust as we transition towards a Network of Information and relate our work with the emerging paradigm of publish/subscribe architectures. We introduce the fundamental components of a Network of Information, i.e., name resolution, routing, storage, and search, and close this paper with a discussion about future work.

  • 44.
    Ahlgren, Bengt
    et al.
    RISE, Swedish ICT, SICS. NETS.
    Dannewitz, Christian
    SAIL.
    Imbrenda, Claudio
    SAIL.
    Kutscher, Dirk
    SAIL.
    Ohlman, Börje
    SAIL.
    A Survey of Information-Centric Networking2012In: IEEE Communications Magazine, ISSN 0163-6804, E-ISSN 1558-1896, Vol. 50, 26-36 p.Article in journal (Refereed)
    Abstract [en]

    The information-centric networking (ICN) concept is a significant common approach of several Future Internet research activities. The approach leverages in-network caching, multi-party communication through replication, and interaction models decoupling senders and receivers. The goal is to provide a network infrastructure service that is better suited to today's use, in particular content distribution and mobility, and that is more resilient to disruptions and failures. The ICN approach is being explored by a number of research projects. We compare and discuss design choices and features of proposed ICN architectures, focussing on the following main components: named data objects, naming and security, API, routing and transport, and caching. We also discuss the advantages of the ICN approach in general.

  • 45.
    Ahlgren, Bengt
    et al.
    RISE, Swedish ICT, SICS. NETS.
    Dannewitz, Christian
    SAIL.
    Imbrenda, Claudio
    SAIL.
    Kutscher, Dirk
    SAIL.
    Ohlman, Börje
    SAIL.
    A Survey of Information-Centric Networking (Draft)2011Conference paper (Refereed)
  • 46.
    Ahlgren, Bengt
    et al.
    RISE, Swedish ICT, SICS. CNA.
    Eggert, Lars
    Ohlman, Börje
    Rajahalme, Jarno
    Schieder, Andreas
    Names, addresses and identities in ambient networks2005Conference paper (Refereed)
    Abstract [en]

    Ambient Networks interconnect independent realms that may use different local network technologies and may belong to different administrative or legal entities. At the core of these advanced internetworking concepts is a flexible naming architecture based on dynamic indirections between names, addresses and identities. This paper gives an overview of the connectivity abstractions of Ambient Networks and then describes its naming architecture in detail, comparing and contrasting them to other related next-generation network architectures.

  • 47.
    Ahlgren, Bengt
    et al.
    RISE, Swedish ICT, SICS. CNA.
    Eggert, Lars
    Ohlman, Börje
    Schieder, Andreas
    Ambient networks: Bridging heterogeneous network domains2005Conference paper (Refereed)
    Abstract [en]

    Providing end-to-end communication in heterogeneous internetworking environments is a challenge. Two fundamental problems are bridging between different internetworking technologies and hiding of network complexity and differences from both applications and application developers. This paper presents abstraction and naming mechanisms that address these challenges in the Ambient Networks project. Connectivity abstractions hide the differences of heterogeneous internetworking technologies and enable applications to operate across them. A common naming framework enables end-to-end communication across otherwise independent internetworks and supports advanced networking capabilities, such as indirection or delegation, through dynamic bindings between named entities.

  • 48.
    Ahlgren, Bengt
    et al.
    RISE, Swedish ICT, SICS. CNA.
    Gunningberg, Per
    A minimal-copy network interface architecture supporting ILP and ALF1994Conference paper (Refereed)
  • 49.
    Ahlgren, Bengt
    et al.
    RISE - Research Institutes of Sweden, ICT, SICS.
    Gunningberg, Per
    RISE - Research Institutes of Sweden, ICT, SICS.
    Moldeklev, Kjersti
    Increasing communication performance with a minimal-copy data path supporting ILP and ALF1996In: Journal of High Speed Networks, Vol. 5, no 2, 203-214 p.Article in journal (Refereed)
    Abstract [en]

    Many current implementations of communication subsystems on workstation class computers transfer communication data to and from primary memory several times. This is due to software copying between user and operating system address spaces, presentation layer data conversion and other data manipulation functions. The consequence is that memory bandwidth is one of the major performance bottlenecks limiting high speed communication on these systems. We propose a communication subsystem architecture with a minimal-copy data path to widen this bottleneck. The architecture is tailored for protocol implementations using Integrated Layer Processing (ILP) and Application Layer Framing (ALF). We choose to implement these protocols in the address space of the application program. We present a new application program interface (API) between the protocols and the communication service in the operating system kernel. The API does not copy data, but instead passes pointers to page size data buffers. We analyze and discuss ILP loop and cache memory requirements on these buffers. Initial experiments show that the API can increase the communication performance with 50% compared to a standard BSD Unix socket interface.

  • 50.
    Ahlgren, Bengt
    et al.
    RISE, Swedish ICT, SICS, Decisions, Networks and Analytics lab.
    Hidell, Markus
    Ngai, Edith
    Internet of Things for Smart Cities: Interoperability and Open Data2016In: IEEE Internet Computing, ISSN 1089-7801, E-ISSN 1941-0131, 52-56 p.Article in journal (Refereed)
    Abstract [en]

    The Internet of Things (IoT) for smart cities needs accessible open data and open systems, so that industries and citizens can develop new services and applications. As an example, the authors provide a case study of the GreenIoT platform in Uppsala, Sweden.

1234567 1 - 50 of 3276
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • 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
v. 2.29.1