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  • 1.
    Ardelius, John
    et al.
    SICS.
    Grönvall, Björn
    SICS.
    Westberg, Lars
    Ericsson AB.
    Arvidsson, Åke
    Ericsson AB.
    On the effects of caching in access aggregation networks2012Inngår i: ICN 2012, Helsinki, Finland / [ed] Dirk Kutscher, Giacomo Morabito, Börje Ohlman, George C. Polyzos, Ignacio Solis och Lixia Zhang, Association for Computing Machinery (ACM), 2012Konferansepaper (Fagfellevurdert)
    Abstract [en]

    All forecasts of Internet trac point at a substantial growth over the next few years. From a network operator perspective, efficient in-network caching of data is and will be a key component in trying to cope with and profit from this increasing demand. One problem, however, is to evaluate the performance of different caching policies as the number of available data items as well as the distribution networks grows very large.

    In this work, we develop an analytical model of an aggregation access network receiving a continuous flow of requests from external clients. We provide exact analytical solutions for cache hit rates, data availability and more. This enables us to provide guidelines and rules of thumb for operators and Information-Centric Network designers.

    Finally, we apply our analytical results to a real VoD trace from a network operator and show that substantial bandwidth savings can be expected when using in-network caching in a realistic setting.

  • 2.
    Arvidsson, Daniel
    et al.
    Högskolan Kristianstad, Sektionen för Hälsa och Samhälle.
    Bergqvist, Joakim
    Högskolan Kristianstad, Sektionen för Hälsa och Samhälle.
    Bünger, Robin
    Högskolan Kristianstad, Sektionen för Hälsa och Samhälle.
    IP-telefoni: en teknisk undersökning2011Independent thesis Basic level (university diploma), 5 poäng / 7,5 hpOppgave
    Abstract [sv]

    Projektet har till syfte att undersöka den revolutionerande tekniken bakom IP-telefoni. Eftersom tekniken är relativt ung så finns det fortfarande mycket att lära om hur det fungerar och hur den används. Projektet behandlar fördelar och nackdelar samt vilka hot som finns och hur man kan känna sig säker när man använder IP-telefoni till vardags. Det primära objektivet med projektet är att få en helhetsbild och förstå hur tekniken verkligen fungerar.

    Vidare behandlas telefonens historia då det är viktigt att se var tekniken har sina rötter och hur den utvecklats sedan dess. Som en röd tråd från telefonens teknologi och det publika telefonnätets rötter görs en jämförelse mellan de två teknologierna för att se skillanderna och förmodade fördelar och nackdelar med de båda systemen. Olika sorters protokoll som har ett nära förhållande till IP-telefoni så som SIP, RTP, UDP och IP behandlas. För att få en sanningsenlig bild över hur vardagliga användare upplever IP-telefoni så har en enkätundersökning angående vanor och möjliga problem gjorts hos de anställda på Region Skåne.

  • 3.
    Arvidsson, Åke
    et al.
    Ericsson AB.
    Du, Manxing
    Acreo.
    Aurelius, Andreas
    Acreo.
    Kihl, Maria
    Lunds universitet.
    Analysis of user demand patterns and locality for YouTube traffic2013Inngår i: 25th International Teletraffic Congress / [ed] Zhisheng Niu. Kurt Tutschku. Zhanhong Xin och Moshe Zukerman, IEEE Communications Society, 2013Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Video content, of which YouTube is a major part, constitutes a large share of residential Internet traffic. In this paper, we analyse the user demand patterns for YouTube in two metropolitan access networks with more than 1 million requestsover three consecutive weeks in the first network and more than 600,000 requests over four consecutive weeks in the second network.

    In particular we examine the existence of “local interest communities”, i.e. the extent to which users living closer to each other tend to request the same content to a higher degree, and it is found that this applies to (i) the two networks themselves; (ii) regions within these networks (iii) households with regions and (iv) terminals within households. We also find that different types of access devices (PCs and handhelds) tend to form similar interest communities.

    It is also found that repeats are (i) “self-generating” in the sense that the more times a clip has been played, the higher the probability of playing it again, (ii) “long-lasting” in the sense that repeats can occur even after several days and (iii) “semi regular”in the sense that replays have a noticeable tendency tooccur with relatively constant intervals.

    The implications of these findings are that the benefits from large groups of users in terms of caching gain may be exaggerated, since users are different depending on where they live and what equipment they use, and that high gains can be achieved in relatively small groups or even for individual users thanks totheir relatively predictable behaviour.

  • 4.
    Arvidsson, Åke
    et al.
    Högskolan Kristianstad, Sektionen för hälsa och samhälle, Avdelningen för Design och datavetenskap. Ericsson AB.
    Rydén, Tobias
    Uppsala University.
    Load transients in pooled cellular core network nodes2015Inngår i: Performance evaluation (Print), ISSN 0166-5316, E-ISSN 1872-745X, Vol. 90, 18-35 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The coverage areas of cellular networks are logically subdivided into service areas. Each service area has a local anchor node which “hides” the mobility inside the area and the entire network has a global anchor node which “hides” the mobility between areas.

    The concept of unique local anchor nodes per service area was invented to simplify routing but has been found to complicate expansion. The rapidly growing demand for cellular access has therefore prompted for alternative solutions with pools of local anchor nodes per service area. Such pools are now deployed by several operators all over the world.

    Users in pooled service areas are mapped to specific pool members according to a load distribution policy, but the mapping can change as a result of node failures or operator interventions. Such changes take a certain time to implement and cause additional load on the anchor nodes. We study these processes in detail and derive closed form expressions which allow operators to control the trade-off between rapid changes and acceptable loads.

    Finally we show that the key assumptions of our model are in agreement with measured data and demonstrate how the model can be applied to investigate the effects of different network settings (timers) under different user behaviour (traffic and mobility).

    Contrary to current solutions to this problem, which typically are slow and/or inaccurate, our results enable fast and accurate analysis of different scenarios thereby enabling operators to maximise utilisation of the existing investments and at the same time avoid potentially dangerous situations of overload.

  • 5.
    Arvidsson, Åke
    et al.
    Ericsson AB.
    Zhang, Ying
    Ericsson AB.
    Detecting user dissatisfaction and understanding the underlying reasons2013Inngår i: ACM SIGMETRICS / International conference on measurement and modeling of computer systems, SIGMETRICS '13, Pittsburgh, PA, USA, June 17-21, 2013 / [ed] John Douceur och Jun Xu, Association for Computing Machinery (ACM), 2013Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Quantifying quality of experience for network applications is challenging as it is a subjective metric with multiple dimensions such as user expectation, satisfaction, and overall experience. Today, despite various techniques to support differentiated Quality of Service (QoS), the operators still lack of automated methods to translate QoS to QoE, especially for general web applications.

    In this work, we take the approach of identifying unsatisfactory performance by searching for user initiated early terminations of web transactions from passive monitoring. However, user early abortions can be caused by other factors such as loss of interests. Therefore, naively using them to represent user dissatisfaction will result in large false positives. In this paper, we propose a systematic method for inferring user dissatisfaction from the set of early abortion behaviors observed from identifying the traffic traces. We conduct a comprehensive analysis on the user acceptance of throughput and response time, and compare them with the traditional MOS metric. Then we present the characteristics of early cancelation from dimensions like the types of URLs and objects. We evaluate our approach on four data sets collected in both wireline network and a wireless cellular network.

  • 6.
    Arvidsson, Åke
    et al.
    Ericsson AB.
    Zhang, Ying
    Ericsson AB.
    Neda, Beheshti
    Ericsson AB.
    Detecting user dissatisfaction from passive monitoring2013Inngår i: Proceedings of Eurocon 2013, International Conference on computer as a tool, Zagreb, Croatia, July 1-4, 2013, IEEE Communications Society, 2013Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In an increasingly competitive environment it is more important than ever for operators to keep their end users satisfied. User satisfaction is often characterised in terms of Quality of Experience (QoE), a subjective metric with multiple dimensions such as expectations, content, terminal, environment, cost and performance. QoE is typically quantified as MOS, mean opinion score, which is obtained by averaging the ranks of a number of voluntary users for controlled combinations content/terminals/performance etc. While this approach has many advantages, there are also a number of difficulties such as representativeness (the number of users as well as the number of objects and devices all have to be kept small); validity (the results may be biased by the situation, the setting, the renumeration and so on); and applicability (it is not clear how different numbers map to notions such as “acceptable” or “unacceptable” and operators alone cannot do very much about factors such as content).

    We thus investigate the possibilities of detecting user opinions in the above, simplified, terms and from the network itself; with actual expectations, content, terminals, environments, costs and performance for virtually all users all the time. To this end we revisit the earlier suggestion that user opinions be reflected in their behaviour such that poor performance may result in interrupted requests. These works have, however, considered single flows hence we extend that idea to web pages which are groups of flows. In this paper we present our methods to group flows, interpret users, and characterise performance and we make a first assessment of the correlations between web page interruptions and network performance characteristics.

  • 7.
    Atxutegi, Eneko
    et al.
    Spanien.
    Grinnemo, Karl-Johan
    Karlstads universitet.
    Izurza, Andoni
    Spanien.
    Arvidsson, Åke
    Högskolan Kristianstad, Sektionen för hälsa och samhälle, Avdelningen för Design och datavetenskap.
    On the move with TCP in current and future mobile networks2017Inngår i: Proceedings of the 8th International Conference on the Network of the Future, London, United Kingdom, November 2017, 2017Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    Mobile wireless networks constitute an indispensable part of the global Internet, and with TCP the dominating transport protocol on the Internet, it is vital that TCP works equally well over these networks as over wired ones. This paper identifies the performance dependencies by analyzing the responsiveness of TCP NewReno and TCP CUBIC when subject to bandwidth variations related to movements in different directions. The presented evaluation complements previous studies on 4G mobile networks in two important ways: It primarily focuses on the behavior of the TCP congestion control in medium- to high-velocity mobility scenarios, and it not only considers the current 4G mobile networks, but also low latency configurations that move towards the overall potential delays in 5G networks. The paper suggests that while both CUBIC and NewReno give similar goodput in scenarios where the radio channel continuously degrades, CUBIC gives a significantly better goodput in scenarios where the radio channel quality continuously increases. This is due to CUBIC probing more aggressively for additional bandwidth. Important for the design of 5G networks, the obtained results also demonstrate that very low latencies are capable of equalizing the goodput performance of different congestion control algorithms. Only in low latency scenarios that combine both large fluctuations of available bandwidths and a mobility pattern in which the radio channel quality continuously increases can some performance differences be noticed.

  • 8.
    Atxutegi, Eneko
    et al.
    Spanien.
    Liberal, Fidel
    Spanien.
    Grinnemo, Karl-Johan
    Karlstad University.
    Brunström, Anna
    Karlstad University.
    Arvidsson, Åke
    Högskolan Kristianstad, Sektionen för hälsa och samhälle, Avdelningen för Design och datavetenskap. Ericsson AB.
    Robert, Rèmi
    Ericsson AB.
    TCP behaviour in LTE: impact of flow start-up and mobility2016Inngår i: Wireless and Mobile Networking Conference (WMNC), 2016 9th IFIP, IEEE Communications Society, 2016, 73-80 s.Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Mobile internet has been widely adopted and it is expected to rise to almost 4 billion users by 2020. Despite the research effort dedicated to the enhancement of its performance, there still exists a gap in the understanding of how TCP and its many variants work over LTE. To this end, this paper evaluates the extent to which five common TCP variants, CUBIC, NewReno,Westwood+, Illinois, and CAIA Delay Gradient (CDG), are able to utilise available radio resources under hard conditions, such as during start-up and in mobile scenarios at different speeds. The paper suggests that CUBIC, due to its Hybrid Slow-Start mechanism, enters congestion avoidance prematurely, and thus experiences a prolonged start-up phase. As a result, it is unable to efficiently utilise radio resources during shorter transmissionsessions. Besides, CUBIC, Illinois and NewReno, i.e., the loss-based TCP implementations, offer better throughput, and are able to better utilise available resources during mobility than Westwood+ and CDG - the delay-based variants do.

  • 9.
    Aurelius, Andreas
    et al.
    Acreo.
    Arvidsson, Åke
    Ericsson AB.
    Heegard, Poul
    Norge.
    Villa, Björn
    Norge.
    Kihl, Maria
    Lunds Universitet.
    Zhang, Yichi
    Kungliga Tekniska Högskolan.
    How much of the bandwidth do we actually use?: an investigation of residential access traffic load2012Inngår i: ICTON 2012 / [ed] Bozena Jaskorzynska och Richard De La Rue, IEEE Communications Society, 2012Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Internet traffic from a fibre based residential access network is investigated concerning traffic volumes and link load. Also the cost of the services is analyzed. We show that 1 Mbps accesses subscribers maintain high loads, and that the price they pay per GB used is five times higher than the one paid by 100 Mbps access subscribers.

  • 10.
    Du, Manxing
    et al.
    Acreo.
    Kihl, Maria
    Lund University.
    Arvidsson, Ake
    Högskolan Kristianstad, Sektionen för hälsa och samhälle, Avdelningen för Design och datavetenskap. Lund University.
    Zhang, Huimin
    Uppsala University.
    Lagerstedt, Christina
    Acreo.
    Gawler, Anders
    Acreo.
    Prefetching schemes and performance analysis for TV on demand services2015Inngår i: International Journal On Advances in Telecommunications, ISSN 1942-2601, E-ISSN 1942-2601, Vol. 8, nr 3&4, 162-172 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    TV-on-Demand services have become one of the most popular Internet applications that continuously attracts high user interest. With rapidly increasing user demands, the existing network conditions may not be able to ensure a low start-up delay of video playback. Prefetching has been broadly investigated to cope with the start-up latency problem, which is also known as user perceived latency. In this paper, two datasets from different IPTV providers are used to analyse the TV program request patterns. According to the results, we propose a prefetching scheme at the user end to preload videos before user requests. For both datasets, our prefetching scheme significantly improves the cache hit ratio compared to passive caching and we note that there is a potential to further improve prefetching performance by customizing prefetching schemes for different video categories. We further present a cost model to determine the optimal number of videos to prefetch. We also discuss if there is enough time for prefetching. Finally, more factors, which may have an impact onoptimizing prefetching performance, are further discussed, such as the jump patterns over different time in a day and the the distribution of each video’s viewing length.

  • 11.
    Du, Manxing
    et al.
    Acreo Swedish ICT.
    Kihl, Maria
    Lund University.
    Arvidsson, Åke
    Högskolan Kristianstad, Sektionen för hälsa och samhälle, Avdelningen för Design och datavetenskap. Ericsson AB.
    Lagerstedt, Christina
    Acreo Swedish ICT.
    Gawler, Anders
    Acreo Swedish ICT.
    Analysis of prefetching schemes for TV-on-Demand service2015Inngår i: ICDT 2015 : the Tenth International Conference on Digital Telecommunications / [ed] Tapio Saarelainen, International Academy, Research and Industry Association (IARIA), 2015Konferansepaper (Fagfellevurdert)
    Abstract [en]

    TV-on-Demand service has become one of the most popular Internet applications that continuously attracts higher user interests. With rapidly increasing user demand, the existing network conditions may not be able to ensure low start-up delay of video playback. Prefetching has been broadly investigated to cope with the start-up latency problem which is also known as user perceived latency. In this paper, we analyse request patterns for TV programs from a popular Swedish TV service provider over 11 weeks. According to the analysis, we propose a prefetching scheme at the user end to preload videos before user requests. Our prefetching scheme significantly improves the cache hit ratio compared to terminal caching and we note that there is a potential to further improve prefetching performance by customizing prefetching schemes for different video categories. We further present a cost model to determine the optimal number of videos to prefetch. Finally, we discuss available time for prefetching and suggest that when to make prefetching decisions depends on the user demand patterns of different video categories.

  • 12.
    Huang, Qian
    et al.
    Högskolan Kristianstad, Sektionen för hälsa och samhälle.
    Yin, Qin
    Högskolan Kristianstad, Sektionen för hälsa och samhälle.
    Study on Electronic Health Record and its Implementation2012Independent thesis Advanced level (degree of Master (One Year)), 10 poäng / 15 hpOppgave
    Abstract [en]

    This degree project deals with electronic health record (EHR). The report is divided into two main sections; literature study on electronic health record and an EHR system implementation. In the literature study section, EHR background, development history and service condition are introduced. The paper focuses on the sharing of medical information in different users, data safety and privacy. The adjunctions of computer science, technologies are used to solve the medical informatics’ problems. In the implementation section, based on the study of the current EHR systems, the design and implement of a shared EHR system are presented, which can be accessed by different doctors and patients. Access control function and cryptography protections are included in this system. The system test and evaluation are also given.

  • 13.
    Huang, Xin
    et al.
    Department of Computer Science, Institute for the Future of Computing/Oxford Martin School, University of Oxford.
    Chen, Bangdao
    Department of Computer Science, University of Oxford.
    Markham, Andrew
    Department of Computer Science, Institute for the Future of Computing/Oxford Martin School, University of Oxford.
    Wang, Qinghua
    Högskolan Kristianstad, Sektionen för hälsa och samhälle, Avdelningen för Design och datavetenskap. Department of Communications and Networking, Aalto University, Espoo.
    Zheng, Yan
    Department of Communications and Networking, Aalto University, Espoo.
    Roscoe, Andrew William
    Department of Computer Science, Institute for the Future of Computing/Oxford Martin School, University of Oxford.
    Human interactive secure key and ID exchange protocols in body sensor networks2013Inngår i: IET Information Security, ISSN 1751-8709, E-ISSN 1751-8717, Vol. 7, nr 1, 30-38 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A body sensor network (BSN) is typically a wearable wireless sensor network. Security protection is critical to BSNs, since they collect sensitive personal information. Generally speaking, security protection of BSN relies on identity (ID) and key distribution protocols. Most existing protocols are designed to run in general wireless sensor networks, and are not suitable for BSNs. After carefully examining the characteristics of BSNs, the authors propose human interactive empirical channel-based security protocols, which include an elliptic curve Diffie–Hellman version of symmetric hash commitment before knowledge protocol and an elliptic curve Diffie–Hellman version of hash commitment before knowledge protocol. Using these protocols, dynamically distributing keys and IDs become possible. As opposite to present solutions, these protocols do not need any pre-deployment of keys or secrets. Therefore compromised and expired keys or IDs can be easily changed. These protocols exploit human users as temporary trusted third parties. The authors, thus, show that the human interactive channels can help them to design secure BSNs.

  • 14.
    Huang, Xin
    et al.
    Kina.
    Craig, Paul
    Kina.
    Wang, Qinghua
    Högskolan Kristianstad, Sektionen för hälsa och samhälle, Avdelningen för Design och datavetenskap.
    Identity-based association protocols for wireless personal area networks2015Inngår i: Proceedings of The 13th IEEE International Conference on Dependable, Autonomic, and Secure Computing, IEEE conference proceedings, 2015Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Identity based infrastructure allows the public keyof a user to be derived easily from a predefined aspect of theirknown identity such as a phone number, passport number orother universally unique identifier. Recently, H¨olbl and Welzerhave proposed an identity-based key establishment protocol.However, this protocol is found to be vulnerable to man-inthe-middle attacks and impersonation attacks. In this paper,we propose multi-channel identity based protocols for wirelesspersonal area networks which can eliminate these attacks.These protocols alleviate the certificate overhead by using apublic key infrastructure which is suitable for wireless personalarea networks.

  • 15.
    Islam, Toriqul
    et al.
    Högskolan Kristianstad, Sektionen för hälsa och samhälle.
    Khan, Monir Ahmed
    Högskolan Kristianstad, Sektionen för hälsa och samhälle.
    iDream2013Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    This degree project deals with a website that can help people to save, share and utilize their dreams and wishes. Communication is the most important part of our social life and iDream is

    programmed to take dreams and wishes to a social level by creating better understanding

    between people through dreams and wishes.

    It allows people to create dream/wish blogs, read others blogs through a gallery, subscribing to other people’s blogs and getting automatic feed from subscribed blogs. Popular blogs become a community which can maximize the effect of the dream or wish and finally an option to add family members and see their activities.

    Joomla CMS is the core of the website. The project also includes research on efficient Joomla component creation and 3D website design according to Human-computer interaction principles.

  • 16.
    Jin, Shasha
    et al.
    Högskolan Kristianstad, Sektionen för hälsa och samhälle.
    Gaoding, Ningcheng
    Högskolan Kristianstad, Sektionen för hälsa och samhälle.
    Signal processing using the wavelet transform and the Karhunen-Loeve transform2012Independent thesis Advanced level (degree of Master (One Year)), 10 poäng / 15 hpOppgave
    Abstract [en]

    This degree project deals with Wavelet transform and Karhunen-Loeve transform. Through the mathematic description to understand and simulation to investigate the denoise ability of WT and the de-correlation ability of KLT. Mainly prove that the new algorithm which is the joint of these two algorithms is feasible.

  • 17.
    Jun, Lu
    et al.
    Högskolan Kristianstad, Sektionen för hälsa och samhälle.
    Song, Zhang
    Högskolan Kristianstad, Sektionen för hälsa och samhälle.
    E-health web application framework and platform based on the cloud technology2013Independent thesis Advanced level (degree of Master (One Year)), 10 poäng / 15 hpOppgave
    Abstract [en]

    This project deals with E-health web application framework, cloud platform and responsive web design which aim to adjust the presentation on mobile devices. This work presents the whole development process of the self-care management web-app framework which provides instructive supports for future other E-health field application. The report consists of the following main parts: analysis, design and implementation, and evaluation. Literature review and internet search are main methods for making an investigation on existing systems and related works. A prototype is developed by using .Net, CSS3, Java script and HTML5 technologies. The system test and evaluation is made to show the system’s usability.

  • 18.
    Kihl, Maria
    et al.
    Lunds Universitet.
    Larsson, Robin
    Lunds Universitet.
    Unnervik, Niclas
    Lunds Universitet.
    Haberkamm, Jolina
    Lunds Universitet.
    Arvidsson, Åke
    Högskolan Kristianstad, Sektionen för hälsa och samhälle, Avdelningen för Design och datavetenskap. Ericsson AB.
    Aurelius, Andreas
    Acreo.
    Analysis of Facebook content demand patterns2014Inngår i: SaCoNet 2014 / [ed] Said Hoceini, Guang-Jie Ren och Eva Marín-Tordera, IEEE Communications Society, 2014Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Data volumes in communication networks increase rapidly. Further, usage of social network applications is very wide spread among users, and among these applications, Facebook is the most popular. In this paper, we analyse user demands patterns and content popularity of Facebook generated traffic. The data comes from residential users in two metropolitan access networks in Sweden, and we analyse more than 17 million images downloaded by almost 16,000 Facebook users. We show that the distributions of image popularity and user activity may be described by Zipf distributions which is favourable for many types of caching. We also show that Facebook activity is more evenly spread over the day, compared to more defined peak hours of general Internet usage. Looking at content life time, we show that profile pictures have a relatively constant popularity while for other images there is an initial, short peak of demand, followed by a longer period of significantly lower and quite stable demand. These findings are useful for designing network andQoE optimisation solutions, such as predictive pre-fetching, proxy caching and delay tolerant networking.

  • 19.
    Kreuger, Per
    et al.
    SICS.
    Gillblad, Daniel
    SICS.
    Arvidsson, Åke
    Högskolan Kristianstad, Sektionen för hälsa och samhälle, Avdelningen för Design och datavetenskap. Ericsson AB.
    zCap: a zero configuration adaptive paging and mobility management mechanism2013Inngår i: International Journal of Network Management, ISSN 1055-7148, E-ISSN 1099-1190, Vol. 23, nr 4, 235-258 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Today, cellular networks rely on fixed collections of cells (tracking areas) for user equipment localisation. Locating users within these areas involves broadcast search (paging), which consumes radio bandwidth but reduces the user equipment signalling required for mobility management. Tracking areas are today manually configured, hard to adapt to local mobility and influence the load on several key resources in the network. We propose a decentralised and self-adaptive approach to mobility management based on a probabilistic model of local mobility. By estimating the parameters of this model from observations of user mobility collected online, we obtain a dynamic model from which we construct local neighbourhoods of cells where we are most likely to locate user equipment. We propose to replace the static tracking areas of current systems with neighbourhoods local to each cell. The model is also used to derive a multi-phase paging scheme, where the division of neighbourhood cells into consecutive phases balances response times and paging cost. The complete mechanism requires no manual tracking area configuration and performs localisation efficiently in terms of signalling and response times. Detailed simulations show that significant potential gains in localisation efficiency are possible while eliminating manual configuration of mobility management parameters. Variants of the proposal can be implemented within current (LTE) standards.

  • 20.
    Kreuger, Per
    et al.
    SICS.
    Gillblad, Daniel
    SICS.
    Arvidsson, Åke
    Ericsson AB.
    Zero configuration adaptive paging (zCap)2012Inngår i: VTC Fall 2012 / [ed] Jean-Yves Chouinard, Fabrice Labeau och Alex Stephenne, IEEE Communications Society, 2012Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Today, cellular networks rely on fixed collections of cells (tracking areas) for handset localisation. This management parameter is manually configured and maintained and is not regularly adapted to changes in use patterns. We present a decentralised approach to localisation, based on a self-adaptive probabilistic mobility model. Estimates of model parameters are built from observations of mobility patterns collected online using a distributed algorithm. Based on these estimates, dynamic local neighbourhoods of cells are formed and maintained by the mobility management entities of the network. These neighbourhoods replace the static tracking areas used in current implementations by using the tracking area list facility of LTE. The model is also used to derive a multi phase paging scheme, where the division of cells into consecutive phases is optimal with respect to a set balance between response times and paging cost. The approach requires no manual tracking area configuration, and performs localisation efficiently in terms of number of location updates, page

  • 21.
    Krznaric, Anton
    Högskolan Kristianstad, Sektionen för hälsa och samhälle.
    License Management for EBITool2013Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    This degree project deals with license management for EBITool. It´s about providing protection and monitoring for a Java Application via a license server, and the construction of it. An analysis that discusses the approach and other possible courses of action is also included. Additionally, it covers a discussion of a prototype implementation of the model solution from the analysis.

    The prototype is a Java EE application that deploys to JBoss AS7. It´s developed using the JBoss Developer Studio 5.0.0, an Eclipse IDE with JBoss Tools preinstalled. It exposes web services to Java Applications through SOAP via JAX-WS. Using Hibernate, the web service Enterprise Java Beans get access to a PostgreSQL 9.1 database via entity classes mapped to the database through the Java Persistence API.

  • 22.
    Laulajainen, Jukka-Pekka
    et al.
    VTT.
    Arvidsson, Åke
    Högskolan Kristianstad, Sektionen för hälsa och samhälle, Avdelningen för Design och datavetenskap. Ericsson AB.
    Ojala, Timo
    Finland.
    Seppänen, Janne
    VTT.
    Du, Manxing
    Acreo.
    Study of YouTube demand patterns in mixed public and campus WiFi network2014Inngår i: TRAC 2014 / [ed] Pedro Casas och Brian Trammell, IEEE Communications Society, 2014Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this paper we study traffic patterns in a large municipal WiFi network and in particular those of the most bandwidth hungry application, viz. YouTube, for which we provide a detailed analysis of demand in different geographical areas and over time. We consider the possibilities to reduce network traffic and increase Quality of Experience (QoE) by serving repeated requests for YouTube videos from caches placed either at the network head end, at the wireless access points, or in the user devices. Our data confirms that a significant part of the YouTube traffic can be served by such devices and that there exists a potential to optimize caching performance by exploiting the content demand locality. We also discover a previously unknown pattern of periodicity in content demand and present a simple example of how to exploit this in cache design.

  • 23.
    Li, Jie
    et al.
    Acreo.
    Aurelius, Andreas
    Acreo.
    Du, Manxing
    Acreo.
    Wang, Hantao
    Ericsson AB.
    Arvidsson, Åke
    Ericsson AB.
    Kihl, Maria
    Lunds universitet.
    YouTube traffic content analysis in the perspective of clip category and duration2013Inngår i: 2013 Fourth International Conference on the Network of the Future (NOF 2013): proceedings of a meeting held 23-25 October 2013, Pohang, South Korea / [ed] Noura Limam och Young-Joo Su, IEEE Communications Society, 2013Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this work, we study YouTube traffic characteristics in a medium-sized Swedish residential municipal network that has ~ 2600 mainly FTTH broadband-connected households. YouTube traffic analyses were carried out in the perspective of video clip category and duration, in order to understand their impact on the potential local network caching gains. To the best of our knowledge, this is the first time systematic analysis of YouTube traffic content in the perspective of video clip category and duration in a residential broadband network. Our results show that the requested YouTube videoclips from the end users in the studied network were imbalanced in regarding the video categories and durations. The dominating video category was Music, both in terms of the total traffic share as well as the contribution to the overall potential local network caching gain. In addition, most of the requested video clips were between 2-5 min in duration, despite video clips with durations over 15 min were also popular among certain video categories, e.g. film videos.

  • 24.
    Li, Jie
    et al.
    Acreo.
    Aurelius, Andreas
    Acreo.
    Nordell, Viktor
    Acreo.
    Du, Manxing
    Acreo.
    Arvidsson, Åke
    Ericsson AB.
    Kihl, Maria
    Lunds universitet.
    A five year perspective of traffic pattern evolution in a residential broadband access network2012Inngår i: Future Network & MobileSummit 2012 / [ed] Paul Cunningham och Miriam Cunningham, 2012Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this paper we describe a systematic study on long-term evolution of residential broadband Internet traffic covering 5 calendar years from June 2007 to May 2011. The traffic evolution is characterized both in the term of the total traffic volume, as well as the traffic volumes and shares for different application categories (file sharing, video streaming etc.), with the focus on comparing the traffic on the per IP user basis and among different broadband subscription groups. The results show that the average daily total traffic generated by each private end user increased only by about 33 % during the past 5 years. Further, the results show that the P2P filesharing has been dominating the network total traffic, but the daily file-sharing traffic volume per end user largely remains the same. Also, the daily streaming-media traffic volume per end user has increased dramatically by over 500% during the studied period of time. In the meantime, the daily web-browsing traffic volume per end user has increased by about 300%. Finally, a further investigation among 4 different FTTH broadband subscription groups with 1, 10 , 30, and 100 Mbit/s symmetric access speeds shows that the lower the access speed, the more diversified the end user traffic tend to be.

  • 25.
    Li, Jie
    et al.
    Acreo.
    Wu, Jinlong
    Kungliga Tekniska Högskolan.
    Dán, György
    Kungliga Tekniska Högskolan.
    Arvidsson, Åke
    Ericsson AB.
    Kihl, Maria
    Lund University.
    Performance analysis of local caching replacement policies for internet video streaming services2014Inngår i: SoftCOM 2014 / [ed] Dinko Begusi och Nikola Rozic, IEEE Communications Society, 2014Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this work, the performance of 5 representative caching replacement policies was investigated and compared for caching Internet video-on-demand (VoD) in local access networks. Two measured traces of end-user requests were used in the analyses for two typical VoD services: TV-on-demand and user generated content represented by YouTube. The studied policies range from simple least recently used (LRU) and least frequently used (LFU) algorithms to more advanced ones denoted as LFU-dynamic lifespan (LFU-DL), Adaptive replacement cache (ARC) and Greedy-dual size frequency (GDSF). Our results show that the ARC policy always outperforms the other policies due to its adaptive nature and its ability to track changes in the traffic patterns. On the other hand, the simple LRU policy can also achieve a caching performance which is comparable to that of the more advanced ARC policy especially for the TV-on-demand service when the potential caching gain is high. On the contrary, the simple LFU policy always shows the poorest performance.However, by applying a proper lifespan supplement under the LFU-DL policy, the caching performance can be effectively enhanced to the level achievable using ARC and LRU policies. Moreover, the GDSF policy does not outperform simple LRU or LFU-DL, especially for YouTube video clips when the potential caching gain is relatively low. The advantage of GDSF manifested in our analysis is, however, its outstanding cache space usage efficiency among the five studied caching algorithms.

  • 26.
    Nordell, Viktor
    et al.
    Acreo.
    Aurelius, Andreas
    Acreo.
    Gawler, Anders
    Acreo.
    Arvidsson, Åke
    Högskolan Kristianstad, Sektionen för hälsa och samhälle, Avdelningen för Design och datavetenskap. Ericsson AB.
    Kihl, Maria
    Lunds universitet.
    Concurrency and locality of content demand2013Inngår i: 2013 International Conference on Smart Communications in Network Technologies (SaCoNeT 2013): proceedings of a meeting held 17-19 June 2013, Paris, France / [ed] Jorge López de Vergara och Brice Agustin, 2013Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Distribution of media data over the Internet is increasing in popularity and volume. This poses challenges not only for network operators but also for service providers when it comes to serving the demand in a cost-efficient way. In this paper, we approach this problem by investigating the potential of co-operative approaches where locality in space (users in the same network) and locality in time (concurrent downloads) are exploited such that as many requests as possible may behandled inside the access and metro networks. This approach may contribute not only to reducing transport costs (less traffic in core networks and at peering points) by but also improve the end user experience (by reduced round trip times and exclusion of some possible bottlenecks). To this end we develop a method to measure the possible gains from, firstly, optimal handling of concurrent downloads and, secondly, optimal utilization localavailability. We apply the method to BitTorrent data from two metropolitan access networks and find that the bandwidth savings amount to between 10% and 20% when optimizing concurrent downloads and between 56% and 66% when exploiting local availability with a simulated network cache.

  • 27.
    Nordström, Johan
    et al.
    Högskolan Kristianstad, Sektionen för hälsa och samhälle.
    Jönsson, Thommie
    Högskolan Kristianstad, Sektionen för hälsa och samhälle.
    Orderhantering via Android2012Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    This degree project deals with creating an Android application for managing representation orders placed in stores as well as evaluating Androids usage as a platform for that line of work. The evaluation will be based on tests of the application on an Android phone together with a survey consisting of written questions and a practical test of the application.

  • 28.
    Rihm, Sivert
    et al.
    Högskolan Kristianstad, Sektionen för hälsa och samhälle.
    Olsson, Mikael
    Högskolan Kristianstad, Sektionen för hälsa och samhälle.
    Bring Your Own Device: what is it good for2013Independent thesis Basic level (university diploma), 5 poäng / 7,5 hpOppgave
    Abstract [sv]

    Vad är BYOD (Bring Your Own Device)? BYOD är en relativt ny trend som går ut på att anställda på ett företag får möjlighet att ta med sina egna elektroniska produkter såsom smarta telefoner, surfplattor och bärbara datorer. Det dyker upp rubriker om fenomenet BYOD (Bring Your Own Device) i diverse tekniska nättidningar och under utbildningens gång har det funnits lärare som berört ämnet lite löst. Detta väckte en nyfikenhet för att gräva djupare i ämnet, eftersom det verkade vara en trend på uppgång. Detta är en så pass ny företeelse att många företag inte vet hur de ska hantera detta i sitt nätverk. Företagen har också fått omvärdera sina säkerhetspolicys.

  • 29.
    Robert, Rèmi
    et al.
    Ericsson AB.
    Atxutegi, Eneko
    Spanien.
    Arvidsson, Åke
    Högskolan Kristianstad, Sektionen för hälsa och samhälle, Avdelningen för Design och datavetenskap. Ericsson AB.
    Liberal, Fidel
    Spanien.
    Brunström, Anna
    Karlstads Universitet.
    Grinnemo, Karl-Johan
    Karlstads Universitet.
    Behaviour of Common TCP Variants over LTE2016Inngår i: IEEE Globecom 2016: Mobile and Wireless Networks Symposium, 2016Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper presents our work regarding the comparison of the behaviour of some of the major TCP variants in a LTE network. Using the LENA LTE simulator and the DCE framework, the behaviour of the Linux implementations of seven TCP variants are compared. The evolution of the throughput, congestion window and queuing delay are studied for four scenarios with different network loads and flow types. Our measurements show that, in the situations we consider, most variants are able to quickly reach full link utilisation. However, to reach the same throughput, they create different amounts of queuing delay. On the one hand, loss based algorithms tend to totally fill the queue, creating huge queuing delays and inducing packet losses. On the other hand, delay based variants manage to limit the queue size and decrease the amount of packet dropped by the eNodeB but struggle to reach the maximum throughput in some circumstances.

  • 30.
    Shala, Ubejd
    et al.
    Högskolan Kristianstad, Sektionen för hälsa och samhälle.
    Rodriguez, Angel
    Högskolan Kristianstad, Sektionen för hälsa och samhälle.
    Indoor Positioning using Sensor-fusion in Android Devices2011Independent thesis Advanced level (degree of Master (One Year)), 10 poäng / 15 hpOppgave
    Abstract [en]

    This project examines the level of accuracy that can be achieved in precision positioning by using built-in sensors in an Android smartphone. The project is focused in estimating the position of the phone inside a building where the GPS signal is bad or unavailable. The approach is sensor-fusion: by using data from the device’s different sensors, such as accelerometer, gyroscope and wireless adapter, the position is determined. The results show that the technique is promising for future handheld indoor navigation systems that can be used in malls, museums, large office buildings, hospitals, etc.

  • 31.
    Song, Qunying
    et al.
    Högskolan Kristianstad, Sektionen för hälsa och samhälle.
    Shen, Hui
    Högskolan Kristianstad, Sektionen för hälsa och samhälle.
    Intelligent Voice Assistant2012Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    This project includes an implementation of an intelligent voice recognition assistant for Android where functionality on current existing applications on other platforms is compared. Until this day, there has not been any good alternative for Android, so this project aims to implement a voice assistant for the Android platform while describing the difficulties and challenges that lies in this task.

  • 32.
    Song, Qunying
    et al.
    Högskolan Kristianstad, Sektionen för hälsa och samhälle.
    Xu, Jingjing
    Högskolan Kristianstad, Sektionen för hälsa och samhälle.
    Study and Implementation of Patient Data Collection and Presentation for an eHealth Application2013Independent thesis Advanced level (degree of Master (One Year)), 10 poäng / 15 hpOppgave
    Abstract [en]

    This degree project is a part of information and communication technology supported self-care system for the diabetes, mainly in diabetes data collection and visualization. The report is organized in four main sections: investigation and internet search, literature review, application design and implementation, system test and evaluation. Existed applications and research studies has been compared and, a responsive web application is developed aiming at providing relevant functionalities and services regarding diabetes self-management.

  • 33.
    Wang, Qinghua
    et al.
    Högskolan Kristianstad, Sektionen för hälsa och samhälle, Avdelningen för Design och datavetenskap.
    Yigitler, Huseyin
    Finland.
    Huang, Xin
    Kina.
    Jäntti, Riku
    Finland.
    Localizing multiple objects using radio tomographic imaging technology2016Inngår i: IEEE Transactions on Vehicular Technology, ISSN 0018-9545, E-ISSN 1939-9359, Vol. 65, nr 5, 3641-3656 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Low data rate wireless networks can be deployed for physical intrusion detection and localization purposes. The intrusion of a physical object (or human) will disrupt the radio frequency magnetic field, and can be detected by observing the change of radio attenuation. This gives the basis for the radio tomographic imaging technology which has been recently developed for passively monitoring and tracking objects. Due to noise and the lack of knowledge about the number and the sizes of intruding objects, multi-object intrusion detection and localization is a challenging issue. This article proposes an extended VB-GMM (i.e. variational Bayesian Gaussian mixture model) algorithm in treating this problem. The extended VBGMM algorithm applies a Gaussian mixture model to model the changed radio attenuation in a monitored field due to the intrusion of an unknown number of objects, and uses a modified version of the variational Bayesian approach for model estimation. Real world data from both outdoor and indoor experiments (using the radio tomographic imaging technology) have been used to verify the high accuracy and the robustness of the proposed multi-object localization algorithm.

  • 34.
    Wang, Qinghua
    et al.
    Högskolan Kristianstad, Sektionen för hälsa och samhälle, Avdelningen för Design och datavetenskap. Aalto University, Finland.
    Yigitler, Huseyin
    Aalto University, Finland.
    Jäntti, Riku
    Aalto University, Finland.
    System monitoring and fault diagnosis in wireless sensor systems2012Inngår i: Aalto University Workshop on Wireless Sensor Systems, WoWSS 2012, 2012Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this paper, we discuss fault diagnosis for wireless sensor systems. Fault diagnosis is only possible if comprehensive system monitoring is in place. We thus also present architecture for in-depth system monitoring.

  • 35.
    Zhang, Ying
    et al.
    Ericsson AB.
    Arvidsson, Åke
    Ericsson AB.
    Understanding the characteristics of cellular data traffic2012Inngår i: CellNet 2012 / [ed] Li Erran Li och Morley Mao Zhuoqing, Association for Computing Machinery (ACM), 2012Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Because of rapidly growing subscriber populations, advances in cellular communication technology, increasingly capable user terminals, and the expanding range of mobile applications, cellular networks have experienced a significant increase in data traffic, the dominant part of which is carried by the http protocol. Understanding the characteristics of this traffic is important for network design, traffic modeling, resource planning and network control. In this study we present a comprehensive characterization study of mobile http-based traffic using packet level traces collected in a large cellular network. We analyze the traffic using metrics at packet level, flow level and session level. For each metric, we conduct a comparison between traffic from different applications, as well as comparison to traffic in a wired network. Finally, we discuss the implications of our findings for better resource utilization in cellular infrastructures.

  • 36.
    Zhang, Ying
    et al.
    USA.
    Arvidsson, Åke
    Ericsson AB.
    Siekkinen, Matti
    Finland.
    Urvoy-Keller, Guillaume
    Frankrike.
    Understanding HTTP flow rates in cellular networks2014Inngår i: Networking 2014 / [ed] Bjarne Helvik, Deep Medhi och Bin Liu, IFIP , 2014Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Data traffic in cellular networks increased tremendously over the past few years and this growth is predicted to continue over the next few years. Due to differences in access technology and user behavior, the characteristics of cellular traffic can differ from existing results for wireline traffic. In this study we focus on understanding the flow rates and on the relationship between the rates and other flow properties by analyzing packet level traces collected in a large cellular network. To understand the limiting factors of the flow rates, we further analyze the underlying causes behind the observed rates, e.g.,network congestion, access link or end host configuration. Our study extends other related work by conducting the analysis from a unique dimension, the comparison with traffic in wired networks, to reveal the unique properties of cellular traffic. We find that they differ in variability and in the dominant rate limiting factors.

1 - 36 of 36
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