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| 2. |
- Abbaspour, Sara, et al.
(författare)
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Web Service Response Time Monitoring : Architecture and Validation
- 2011
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Ingår i: Communications in Computer and Information Science Volume 164 CCIS, 2011. - Berlin, Heidelberg : Springer Berlin Heidelberg. - 9783642249983 ; , s. 276-282
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Konferensbidrag (refereegranskat)abstract
- Web services are used in many Web applications in order to save time and cost during software development process. To peruse Web service response time, a suitable tool is needed to automate the measurement of the response time. However, not many suitable tools are available for automatic measurement of response time. This research is carried out in the context of quality of Web services in order to measure and visualize Web service response time. The method proposed in this research for accomplishing this goal is based on creating a proxy for connecting to the required Web service, and then calculating the Web services response time via the proxy. A software tool is designed based on the proposed method in order to guide the implementation that is still in progress. The tool can be validated through empirical validation using three test cases for three different Web service access situations.
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| 4. |
- Abdullah, Syed Md Jakaria, et al.
(författare)
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Towards Implementation of Virtual-Clustered Multiprocessor Scheduling in Linux
- 2013
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Ingår i: Proceedings of the 8th IEEE International Symposium on Industrial Embedded Systems, SIES 2013. - 9781479906581 ; , s. 97-100
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Konferensbidrag (refereegranskat)abstract
- Cluster based multiprocessor scheduling can be seen as a hybrid approach combining benefits of both partitioned and global scheduling. Virtual clustering further enhances it by providing dynamic cluster resource allocation and applying hierarchical scheduling techniques. Over the years, the study of virtual cluster scheduling has been limited to theoretical analysis. In this paper, we present our initial ideas about implementing virtual cluster scheduling in Linux. The purpose of this implementation is twofold: (i) we would like to demonstrate the feasibility of its implementation in an operating system, without modifying the kernel source code, (ii) we present practical insights on the overhead of implementing this framework.
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| 5. |
- Abecassis-Moedas, Celine, et al.
(författare)
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Key resources and internationalization modes of creative knowledge-intensive business services : The case of design consultancies
- 2012
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Ingår i: Creativity and Innovation Management. - : Wiley. - 0963-1690 .- 1467-8691. ; 21:3, s. 315-331
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Tidskriftsartikel (refereegranskat)abstract
- In the knowledge economy, knowledge-intensive business services (KIBS) are a key driver for innovation and competitiveness. The internationalization of these businesses raises challenges given their specificities such as knowledge intensity, the importance of customer interaction and intimacy in service delivery. This paper focuses on design consultancies as a specific type of creative KIBS for which these characteristics are emphasized. The objective of this research is to analyse the resources leveraged by the firms to compete internationally. It is based on 11 case studies of design consultancies located in five different countries (France, Italy, Portugal, Spain and the UK) that were selected for their capacity to perform at the international level for several years. The paper advances three internationalization modes depending on contingent variables and focusing on specific resources that enable international competitiveness: star-based, process-based and glocality-based. In star-based creative KIBS, the individual designer has developed a reputation that attracts customers internationally, operating as a brand. In process-based creative KIBS, the reputation of a collective creative process attracts clients from other countries. In glocality-based creative KIBS, the geographical proximity obtained by opening international offices helps to develop a close understanding of the client through frequent interactions, and also to know the client's market well and to better understand local codes and signs. These modes complement those presented in the existing internationalization literature which takes the peculiarities of creative KIBS into consideration.
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| 6. |
- Abrahamsson, Gun, 1977-, et al.
(författare)
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Ekonomiska ansvarsenheter
- 2013. - 1
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Ingår i: Perspektiv på ekonomistyrning. - Stockholm : Liber. - 9789147096947 ; , s. 14-35
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 7. |
- Abrahamsson, Henrik, et al.
(författare)
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Caching for IPTV distribution with time-shift
- 2013. - 7
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Ingår i: 2013 International Conference on Computing, Networking and Communications, ICNC 2013. - : IEEE. - 9781467352888 ; , s. 916-921
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Konferensbidrag (refereegranskat)abstract
- Today video and TV distribution dominate Internet traffic and the increasing demand for high-bandwidth multimedia services puts pressure on Internet service providers. In this paper we simulate TV distribution with time-shift and investigate the effect of introducing a local cache close to the viewers. We study what impact TV program popularity, program set size, cache replacement policy and other factors have on the caching efficiency. The simulation results show that introducing a local cache close to the viewers significantly reduces the network load from TV-on-Demand services. By caching 4% of the program volume we can decrease the peak load during prime time by almost 50%. We also show that the TV program type and how program popularity changes over time can have a big influence on cache hit ratios and the resulting link loads.
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| 8. |
- Abrahamsson, Henrik
(författare)
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Network overload avoidance by traffic engineering and content caching
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- 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.
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| 9. |
- Abrahamsson, Henrik, et al.
(författare)
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Program Popularity and Viewer Behaviour in a Large TV-on-Demand System
- 2012. - 7
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Ingår i: IMC '12 Proceedings of the 2012 ACM conference on Internet measurement conference. - New York, NY, USA : ACM. - 9781450317054 ; , s. 199-210
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Konferensbidrag (refereegranskat)abstract
- Today increasingly large volumes of TV and video are distributed over IP-networks and over the Internet. It is therefore essential for traffic and cache management to understand TV program popularity and access patterns in real networks. In this paper we study access patterns in a large TV-on-Demand system over four months. We study user behaviour and program popularity and its impact on caching. The demand varies a lot in daily and weekly cycles. There are large peaks in demand, especially on Friday and Saturday evenings, that need to be handled. We see that the cacheability, the share of requests that are not first-time requests, is very high. Furthermore, there is a small set of programs that account for a large fraction of the requests. We also find that the share of requests for the top most popular programs grows during prime time, and the change rate among them decreases. This is important for caching. The cache hit ratio increases during prime time when the demand is the highest, and aching makes the biggest difference when it matters most. We also study the popularity (in terms of number of requests and rank) of individual programs and how that changes over time. Also, we see that the type of programs offered determines what the access pattern will look like.
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| 10. |
- Abrahamsson, Henrik, et al.
(författare)
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Simulation of IPTV caching strategies
- 2010. - 6
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Ingår i: Proceedings of the 2010 International Symposium on Performance Evaluation of Computer and Telecommunication Systems. ; , s. 187-193
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Konferensbidrag (refereegranskat)abstract
- 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.
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