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Träfflista för sökning "WFRF:(Isaksson Lennart) ;pers:(Karlsson Johan)"

Sökning: WFRF:(Isaksson Lennart) > Karlsson Johan

  • Resultat 1-6 av 6
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1.
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2.
  • Chevul, Stefan, et al. (författare)
  • Measurements of Application-Perceived Throughput in DAB, GPRS, UMTS and WLAN Environments
  • 2005
  • Konferensbidrag (refereegranskat)abstract
    • Communication services are expected to deliver the desired information in a timely manner without challenging the user’s patience. The corresponding offers by networks are reflected in user- or applications-perceived throughput, which is measured end-to-end for different mobile and wireless networks, namely Digital Audio Broadcast (DAB), General Packet Radio Service (GPRS), Universal Mobile Telecommunication Systems (UMTS), and Wireless Local Area Networks (WLAN). The measurements are based on passive monitoring of throughput statistics for active test traffic and reveal amongst others different kinds of changes of traffic burstiness induced by mobile up- and downlinks and by buffering, respectively. The results will be used for seamless communication, i.e. automatic network selection within the project PIITSA (Personal Information for Intelligent Transport Systems through Seamless communications and Autonomous decisions) aiming at maintaining user-perceived performance and security at the desired levels while keeping communication cost as small as possible.
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3.
  • Fiedler, Markus, et al. (författare)
  • Communication requirements of generic services for Intelligent Transport Systems
  • 2004
  • Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
    • In order to meet their users’ expectations and to be of efficient help for people using or maintaining Intelligent Transport Systems (ITS), related services need efficient support from the underlying communication systems, which in turn requires profound knowledge of those needs. This paper presents an approach to gather services into generic groups and a framework to classify their needs in terms of availability, performance, security and cost in a generic manner. These needs are consequently seen from the user’s perspective, but formulated in a way such that the matching towards technical parameters as e.g. throughput offered by a communication network can be performed. Upon comparing needs with offers, the feasibility of a certain communication technology for a certain type of service can be determined, which in turn helps to choose the right kind of connectivity in order to yield the desired degree of availability, performance, security and cost. This work is carried out within the VINNOVA-sponsored project PIITSA (Personal Information for Intelligent Transport Systems through Seamless communications and Autonomous decisions) conducted by Aerotech Telub, Blekinge Tekniska Högskola, Statens Provningsanstalt Borås and Vägverket, respectively.
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4.
  • Fiedler, Markus, et al. (författare)
  • Generic communication requirements of its-related mobile services as basis for seamless communications.
  • 2005
  • Konferensbidrag (refereegranskat)abstract
    • In order to meet user expectations and to be of efficient help for people using or implementing Intelligent Transport Systems and Services (ITS), mobile ITS-related services need efficient support from the underlying communication systems, which in turn requires profound knowledge of those needs. As a first step towards an optimal automatic choice of communication technologies in order to provide for seamless communications, this paper groups services into generic groups and presents a framework to classify their needs in terms of availability, performance, security and cost in a generic manner. These needs are consequently seen from the user’s perspective, but formulated in a way such that they can be matched towards known network parameters. Upon comparing needs with offers, the feasibility of a certain communication technology for a certain type of service can be determined both proactively and reactively, which helps to automatically select the right kind of connectivity in order to yield the desired degree of availability, performance, security and cost. We motivate for instance the need for determining and monitoring applicationperceived speeds, a multi-level security models and the one-stop service concept. We also provide an example on how these needs can be matched to offers by different networks.
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5.
  • Fiedler, Markus, et al. (författare)
  • Measurements and analysis of application-perceived throughput via mobile links
  • 2005
  • Konferensbidrag (refereegranskat)abstract
    • Application-perceived throughput plays a major role for the performance of networked applications and thus for user experience. Especially in mobile environments, throughput is limited, which is a challenge for applications and users. On this background, this tutorial paper investigates the process of user-perceived throughput in GPRS and UMTS systems seen over rather small averaging intervals. It discusses the corresponding active measurements mimicking the needs of streaming applications and analyzes results with aid of summary statistics, histograms and autocorrelation coefficients. These results reveal a clear influence of the network, seen from variations and autocorrelation of application-perceived throughput mostly on the one-second time scale. Such an influence has to be considered when choosing the right kind of network for a specific task. To that aim, the investigated metrics will serve as input to a multi-criteria decision process to determine the proper network for a specific service. The results indicate that, applications have to cope with considerably large jitter when trying to use the nominal throughputs. In GPRS, the promised average throughputs are not even reached in downlink direction; instead, a quite large amount of packet loss occurs. With aid of causality arguments for an equivalent bottleneck, bounds for the extra delay of the first packet sent via mobile links can in fact be derived from throughput measurements.
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6.
  • Isaksson, Lennart, et al. (författare)
  • Application-Perceived Throughput Process in Wireless Systems
  • 2005
  • Konferensbidrag (refereegranskat)abstract
    • Motivated by the central role and the importance of network throughput for the performance of networked applications and thus for user experience, this paper investigates the process of user-perceived throughput. This throughput is measured on rather small time scales and interpreted with aid of summary statistics, histograms and autocorrelation coefficients. The results including GPRS, UMTS and WLAN measurements reveal a clear influence of the network, seen from variations of application-perceived throughput on the one-second time scale, which has to be considered when choosing the right kind of network for a specific task. The different statistical metrics considered will later be used in our research to maintain the QoS of the service decided by the user. While theoretical throughputs are yielded as expected in UMTS, both GPRS and WLAN do not reach the promised throughput values.
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  • Resultat 1-6 av 6
Typ av publikation
konferensbidrag (5)
annan publikation (1)
Typ av innehåll
refereegranskat (5)
övrigt vetenskapligt/konstnärligt (1)
Författare/redaktör
Isaksson, Lennart (6)
Lindberg, Peter (6)
Fiedler, Markus (6)
Chevul, Stefan (6)
Strandén, Lars (1)
Lärosäte
Blekinge Tekniska Högskola (6)
Språk
Engelska (6)
Forskningsämne (UKÄ/SCB)
Teknik (6)

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