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• 301.
Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap.
The GATM Computer Assisted Reasoning Framework in a Security Policy Reasoning Context2014Inngår i: Proceedings of COGNITIVE 2014, The Sixth International Conference on Advanced Cognitive Technologies and Applications, International Academy, Research and Industry Association (IARIA), 2014, s. 215-219Konferansepaper (Fagfellevurdert)

Humans are often faced with the need to make decisions regarding complex issues where multiple interests need to be balanced, and where there are a number of complex arguments weighing in opposite directions. The ability of humans to understand and internalize the underlying argumentation structure resulting from reasoning about complex issues is limited by the human cognitive ability. The cognitive limit can manifest itself both in relation to an inappropriate level and amount of detail in the presentation of information, as well as in the structuring of the information and the representation of the interrelationships between constituting arguments. The GATM model provides a structured way to represent reasoning, and can be useful both in the decision-making process as well as when communicating a decision. In this work a component-based overview of the GATM model is provided in the context of security policy reasoning, where previous work has shown that decision-making transparency and improved understanding of the reasoning behind a security policy may lead to a beneficial impact on policy compliance.

• 302.
Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013). Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
Delay metrics and delay characteristics: A study of four Swedish HSDPA+ and LTE networks2015Inngår i: 2015 European Conference on Networks and Communications (EuCNC), IEEE, 2015, s. 234-238Konferansepaper (Fagfellevurdert)

Network delays and user perceived latencies are of major importance in many applications in cellular networks. Delays can be measured with multiple approaches and at different protocol layers. This work involves a detailed examination of several delay metrics from a network, transport, and application perspective. The study explores base delay as well as latency under load, capturing also the effect of buffering. The examination is based on a comprehensive active measurement campaign performed in the networks of four Swedish operators. The results show that the delay captured by different metrics can vary significantly, with delay captured from the TCP three-way-handshake and adaptive ping measurements giving the most consistent results for base network delay in our measurements. As expected, when background traffic is introduced measured delay increases by an order of magnitude due to buffering in the network, highlighting the importance of also capturing latency under load when describing network performance. Finally, using an analytic model of flow completion time, we show that well-selected network measurements can provide a good prediction of higher layer delay performance.

• 303.
Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013). Karlstads universitet, Fakulteten för ekonomi, kommunikation och IT, Avdelningen för datavetenskap. Karlstads universitet, Fakulteten för ekonomi, kommunikation och IT, Centrum för HumanIT.
A Measurement Based Study of TCP Protocol Efficiency in Cellular Networks2014Inngår i: Modeling and Optimization in Mobile, Ad Hoc, and Wireless Networks (WiOpt), 2014 12th International Symposium on, IEEE, 2014, s. 131-136Konferansepaper (Fagfellevurdert)

This paper examines the efficiency of resource utilization with respect to short-lived TCP flows in various cellular networks. The examination is done from the vantage point of an end-user who would like to use as much as possible of the cellular transmission resources that are available at any given time, thus minimizing the delays associated with communication. Based on a comprehensive measurement campaign we first derive network characteristics with regards to base RTT, RTT under load, and average throughput. A protocol efficiency metric is introduced to capture how efficiently short TCP flows are in fact able to use the instantaneously available transmission resources in a cellular network. The measurements show that short TCP connections have low efficiency in 3. SG (HSPA+) and 4G (LTE) mobile broadband networks, and that the improved latency and throughput characteristics of 4G in relation to 3. SG nevertheless results in lower short-flow efficiency for 4G.

• 304.
Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013). Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
Estimating data transfer capacity for intermittent connectivity: A transport aware model2016Inngår i: 2016 IEEE 27th Annual International Symposium On Personal, Indoor, And Mobile Radio Communications (PIMRC), New York: IEEE, 2016, s. 1-6Konferansepaper (Fagfellevurdert)

Communication performed with mobile devices will experience varying levels of connectivity as the communication device moves in and out of coverage. A subset of mobile communication devices operate under conditions where the connectivity is characterized by relatively short contact periods occurring intermittently. In this paper we propose a model to predict the amount of data that can be transferred during such short contact periods. The model includes aspects of the transport layer slow-start behavior and is validated using data from a long-running measurement campaign in the networks of four Swedish cellular networks. Further validation of the modeling assumptions is performed by employing a numerical optimization technique based on non-linear least squares regression using the iterative Levenberg-Marquardt approach. The model is then used to explore the relevant parameter space.

• 305.
Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013). Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
Examining cellular access systems on trains: Measurements and change detection2017Inngår i: Proceedings of the 1st Network Traffic Measurement and Analysis Conference, New York: IEEE, 2017, s. 1-6Konferansepaper (Fagfellevurdert)

Abstract:Access to reliable high-quality communication services on trains is important for today's mobile users. Train-mounted aggregation routers that provide WiFi access to train passengers and bundle external communication over multiple cellular modems/links is an efficient way of providing such services. Still, the characteristics of such systems have received limited attention in the literature. In this paper we examine the communication characteristics of such systems based on a large data set gathered over six months from an operational Swedish railway system. We characterize the conditions in terms of usage load, train velocity profiles, and observed throughput and delay as well as the relation between these parameters. Furthermore, we examine the data from an anomaly detection perspective. Based on a changepoint detection method, we examine how the collected metrics varies over the six months. Being able to detect shifts in the metrics over time can help detect anomalous changes in the hardware or environment, and also further helps explain the factors affecting the observed behaviors.

• 306.
Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013). Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
Examining TCP Short Flow Performance in Cellular Networks Through Active and Passive Measurements2015Inngår i: AllThingsCellular '15 Proceedings of the 5th Workshop on All Things Cellular: Operations, Applications and Challenges / [ed] David Choffnes and Kobus Van der Merwe, Association for Computing Machinery (ACM), 2015, s. 7-12Konferansepaper (Fagfellevurdert)

In this study we examine the conditions in a current cellular network by examining data passively collected in the core of a cellular operator during a 24-hour period. More than 2 billion traffic measurement data points from over 500,000 cellular users are analyzed. The analysis characterizes the Time-of-Day (ToD) variations for traffic intensity and session length and serves as a complement to the active measurements also performed. A comprehensive active measurement campaign was completed in the HSDPA+ and LTE networks of the four major Swedish operators. We collect around 50,000 data points from stationary cellular modems and analyze the ToD variation pattern for underlying network layer metrics such as delay and throughput. In conjunction with the time-varying session size distribution obtained from the passive measurements, we then analyze the ToD impact on TCP flows of varying sizes. The ToD effects are examined using time series analysis with Lomb-Scargle periodograms and differential Bayesian Information Criterion to allow comparison of the relative impact of the network ToD effects. The results show that ToD effects are predominantly impacting longer-running flows, and although short flows are also impacted they are mostly constrained by other issues such as protocol efficiency.

• 307.
Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013). Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013). Center for Wireless Systems, KTH.
Train Velocity and Data Throughput: A Large Scale LTE Cellular Measurements Study2017Inngår i: Proceedings of the 2017 IEEE 86th Vehicular Technology Conference (VTC Fall), New York: IEEE, 2017, s. 1-6Konferansepaper (Fagfellevurdert)

Train-mounted aggregation routers that provide WiFi access to train passengers and bundle external communication over multiple cellular modems/links is an efficient way of providing communication services on trains. However, the characteristics of such systems have received limited attention in the literature. In this paper we address this gap by examining the communication characteristics of such systems based on a large data set gathered over six months from an operational Swedish railway system. We focus our examination on the relationship between per link throughput and train velocity. Using Levenberg- Marquardt non-linear regression a noticeable critical point is observed for an RS-SINR of around 12 dB. At this point the impact of increased train velocity on per link throughput changes from being negative to becoming positive. Using a machine learning approach we also explore the relative importance of several observed metrics in relation to per link throughput.

• 308.
Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
Clustering-based separation of media transfers in DPI-classified cellular video and VoIP traffic2018Inngår i: 2018 IEEE Wireless Communications and Networking Conference (WCNC), IEEE, 2018Konferansepaper (Fagfellevurdert)

Identifying VoIP and video traffic is often useful in the context of managing a cellular network, and to perform such traffic classification deep packet inspection (DPI) approaches are often used. Commercial DPI classifiers do not necessarily differentiate between, for example, YouTube traffic that arises from browsing inside the YouTube app, and traffic arising from the actual viewing of a YouTube video. Here we apply unsupervised clustering methods on such cellular DPI-labeled VoIP and video traffic to identify the characteristic behavior of the two sub-groups of media-transfer and non media-transfer flows. The analysis is based on a measurement campaign performed inside the core network of a commercial cellular operator, collecting data for more than two billion packets in 40+ million flows. A specially instrumented commercial DPI appliance allows the simultaneous collection of per packet information in addition to the DPI classification output. We show that the majority of flows falls into clusters that are easily identifiable as belonging to one of the traffic sub-groups, and that a surprising majority of DPIlabeled VoIP and video traffic is non-media related.

• 309.
Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap.
Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap.
Deterministic network emulation using KauNetEm2016Konferansepaper (Annet vitenskapelig)

This paper presents KauNetEm, an extension to the Linux-based NetEm emulator that provides deterministic network emulation. KauNetEm enables precise and repeatable placement of NetEm emulation effects, a functionality that canconsiderably simplify several aspects of protocol evaluation. KauNetEm can be instructed to drop specific packets, apply a configurable delay or other emulation effects at predefinedpoints in time. The motivation for deterministic emulation, the overall design of KauNetEm, and usage examples are provided

• 310.
Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
Getting What You Want When You Want It: Deterministic Network Emulation2016Konferansepaper (Fagfellevurdert)

This paper presents KauNetEm, an extension to the Linux-based NetEm emulator that provides deterministic network emulation. KauNetEm enables precise and repeatable placement of NetEm emulation effects, a functionality that can considerably simplify several aspects of protocol evaluation. KauNetEm can be instructed to drop specific packets, apply a configurable delay or other emulation effects at predefined points in time. The motivation for deterministic emulation, the overall design of KauNetEm, and usage examples are provided.

• 311.
Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
Efficient Distribution-Derived Features for High-Speed Encrypted Flow Classification2018Inngår i: NetAI'18 Proceedings of the 2018 Workshop on Network Meets AI & ML, New York: Association for Computing Machinery (ACM), 2018, s. 21-27Konferansepaper (Fagfellevurdert)

Flow classification is an important tool to enable efficient network resource usage, support traffic engineering, and aid QoS mechanisms. As traffic is increasingly becoming encrypted by default, flow classification is turning towards the use of machine learning methods employing features that are also available for encrypted traffic. In this work we evaluate flow features that capture the distributional properties of in-flow per-packet metrics such as packet size and inter-arrival time. The characteristics of such distributions are often captured with general statistical measures such as standard deviation, variance, etc. We instead propose a Kolmogorov-Smirnov discretization (KSD) algorithm to perform histogram bin construction based on the distributional properties observed in the data. This allows for a richer, histogram based, representation which also requires less resources for feature computation than higher order statistical moments. A comprehensive evaluation using synthetic data from Gaussian and Beta mixtures show that the KSD approach provides Jensen-Shannon distance results surpassing those of uniform binning and probabilistic binning. An empirical evaluation using live traffic traces from a cellular network further shows that when coupled with a random forest classifier the KSD-constructed features improve classification performance compared to general statistical features based on higher order moments, or alternative bin placement approaches.

• 312.
Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
On Runtime and Classification Performance of the Discretize-Optimize (DISCO) Classification Approach2018Inngår i: Performance Evaluation Review, ISSN 0163-5999, E-ISSN 1557-9484, Vol. 46, nr 3, s. 167-170Artikkel i tidsskrift (Fagfellevurdert)

Using machine learning in high-speed networks for tasks such as flow classification typically requires either very resource efficient classification approaches, large amounts of computational resources, or specialized hardware. Here we provide a sketch of the discretize-optimize (DISCO) approach which can construct an extremely efficient classifier for low dimensional problems by combining feature selection, efficient discretization, novel bin placement, and lookup. As feature selection and discretization parameters are crucial, appropriate combinatorial optimization is an important aspect of the approach. A performance evaluation is performed for a YouTube classification task using a cellular traffic data set. The initial evaluation results show that the DISCO approach can move the Pareto boundary in the classification performance versus runtime trade-off by up to an order of magnitude compared to runtime optimized random forest and decision tree classifiers.

• 313.
Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013). Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013). Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
Towards Video Flow Classification at a Million Encrypted Flows Per Second2018Inngår i: Proceedings of 32nd International Conference on Advanced Information Networking and Applications (AINA) / [ed] Leonard Barolli, Makoto Takizawa, Tomoya Enokido, Marek R. Ogiela, Lidia Ogiela & Nadeem Javaid, Krakow: IEEE, 2018Konferansepaper (Fagfellevurdert)

As end-to-end encryption on the Internet is becoming more prevalent, techniques such as deep packet inspection (DPI) can no longer be expected to be able to classify traffic. In many cellular networks a large fraction of all traffic is video traffic, and being able to divide flows in the network into video and non-video can provide considerable traffic engineering benefits. In this study we examine machine learning based flow classification using features that are available also for encrypted flows. Using a data set of several several billion packets from a live cellular network we examine the obtainable classification performance for two different ensemble-based classifiers. Further, we contrast the classification performance of a statistical-based feature set with a less computationally demanding alternate feature set. To also examine the runtime aspects of the problem, we export the trained models and use a tailor-made C implementation to evaluate the runtime performance. The results quantify the trade-off between classification and runtime performance, and show that up to 1 million classifications per second can be achieved for a single core. Considering that only the subset of flows reaching some minimum flow length will need to be classified, the results are promising with regards to deployment also in scenarios with very high flow arrival rates.

• 314.
Karlstads universitet, Fakulteten för ekonomi, kommunikation och IT, Avdelningen för datavetenskap. Karlstads universitet, Fakulteten för ekonomi, kommunikation och IT, Centrum för HumanIT. Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
Karlstads universitet, Fakulteten för ekonomi, kommunikation och IT, Avdelningen för datavetenskap. Karlstads universitet, Fakulteten för ekonomi, kommunikation och IT, Centrum för HumanIT. Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
LTE for Trains - Performance Interactions Examined with DL, ML and Resampling2019Inngår i: 2019 IEEE Symposium on Computers and Communications (ISCC), IEEE, 2019Konferansepaper (Fagfellevurdert)

Current LTE networks provide a large fraction of the mobile communication needs. One recent application area that have attained additional interest is the provision of mobile communication services to train passengers. To allow more efficient use of network resources and better onboard communication experience, onboard traffic aggregation can be performed. In this work we examine a large-scale operational data set from a routerbased LTE traffic aggregation system mounted onboard more than 100 trains belonging to a major Swedish train operator. We use both deep learning (DL) with Deep Neural Networks and traditional machine learning (ML) with Random Forests to examine an observed association between train velocity and achieved throughput, which curiously varies over different radio conditions. More than 37000 train journeys are analyzed to explore for structure and learn potential explanatory features. The results indicate that the association has a limited presence on a per cell basis, and that there is only a limited amount of learnable structure per cell. A resampling evaluation shows that the association becomes apparent when cell measurements are aggregated at an order of tens to a hundred cells.

• 315.
Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013). Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013). Icomera AB, Gothenburg, Sweden.
Interactions Between Train Velocity andCellular Link Throughput - An Extensive Study2019Inngår i: 2019 IEEE 30th Annual International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC), 2019Konferansepaper (Fagfellevurdert)

Providing reliable internet connectivity to train passengers can be handled with onboard aggregation routers that use multiple external antennas to simultaneously convey user traffic over multiple links. This work studies the operational characteristics of a large-scale deployment of such a system. The examination focuses on how train velocity is associated with achieved link throughput, and how various interaction effects influence the relationship. A large data set collected over three years is analyzed, indicating that there is a systematic association between train velocity and link throughput that varies over the radio conditions and which is also linked to differences between operators.

• 316.
Moscow State University, Russia.
Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
Fast Algorithm of Square Rooting in Some Finite Fields of Odd Characteristic2018Inngår i: Moscow University Mathematics Bulletin, ISSN 0027-1322, Vol. 73, nr 5, s. 176-181Artikkel i tidsskrift (Fagfellevurdert)

It was proved that the complexity of square root computation in the Galois field GF(3 (s) ), s = 2 (k) r, is equal to O(M(2 (k) )M(r)k + M(r) log(2) r) + 2 (k) kr (1+o(1)), where M (n) is the complexity of multiplication of polynomials of degree n over fields of characteristics 3. The complexity of multiplication and division in the field GF(3 (s) ) is equal to O(M(2 (k) )M(r)) and O(M(2 (k) )M(r)) + r (1+o(1)), respectively. If the basis in the field GF(3 (r) ) is determined by an irreducible binomial over GF(3) or is an optimal normal basis, then the summands 2 (k) kr (1+o(1)) and r (1+o(1)) can be omitted. For M(n) one may take n log(2) n psi(n) where psi(n) grows slower than any iteration of the logarithm. If k grow and r is fixed, than all the estimates presented here have the form O (r) (M (s) log (2) s) = s (log (2) s)(2) psi(s).

• 317.
Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap.
Technical Options for the Implementation of the Principle of ”Right to be Forgotten”2013Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave

The Right-to-be-Forgotten is a part of the new proposal of the Data Protection Directive of the European Union. It was created to react to the challenges in protecting a person’s right of privacy which were caused by the ongoing evolution of technology in our digital age. In the course of the evaluation of the new proposal we created a list of requirements to find technical implementations which could accomplish them. Based on these requirements we established the current state of the art. The EnCoRe project as well as the Vanish project turned out to be the most promising two candidates. EnCoRe on the one hand describes a whole framework which has to be implemented to function. Vanish on the other hand uses existing infrastructures and cryptography to meet its goals. We compared the systems to the requirements of the Right-to-be-Forgotten with the result that both fulfil those to a big extend. Nevertheless there is still much development needed to be able to implement a full-fledged Right-to-be-Forgotten. Therefore future focus should be put on the combination of the different approaches, their further enhancement, securing the environment and improving remote enforcement.

• 318.
University of Bamberg.
University of Bamberg. Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013). University of Bamberg.
BPMN2.0: The state of support and implementation2018Inngår i: Future generations computer systems, ISSN 0167-739X, E-ISSN 1872-7115, Vol. 80, s. 250-262Artikkel i tidsskrift (Fagfellevurdert)
• 319.
Faculty of Human Sciences, Technische Universität Darmstadt, Germany.
Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013). College of Science and Engineering, School of Computing Science, Human-Centred Security and Privacy Lead, University of Glasgow, United Kingdom.
The simpler, the better? Presenting the COPING Android permission-granting interface for better privacy-related decisions2017Inngår i: Journal of Information Security and Applications, ISSN 2214-2134, E-ISSN 2214-2126, Vol. 34, nr 1, s. 8-26Artikkel i tidsskrift (Fagfellevurdert)

One of the great innovations of the modern world is the Smartphone app. The sheer multitude of available apps attests to their popularity and general ability to satisfy our wants and needs. The flip side of the functionality these apps offer is their potential for privacy invasion. Apps can, if granted permission, gather a vast amount of very personal and sensitive information. App developers might exploit the combination of human propensities and the design of the Android permission-granting interface to gain permission to access more information than they really need. This compromises personal privacy. The fact that the Android is the globally dominant phone means widespread privacy invasion is a real concern.

We, and other researchers, have proposed alternatives to the Android permission-granting interface. The aim of these alternatives is to highlight privacy considerations more effectively during app installation: to ensure that privacy becomes part of the decision-making process. We report here on a study with 344 participants that compared the impact of a number of permission-granting interface proposals, including our own (called the COPING interface — COmprehensive PermIssioN Granting) and two Android interfaces. To conduct the comparison we carried out an online study with a mixed-model design.

Our main finding is that the focus in these interfaces ought to be on improving the quality of the provided information rather than merely simplifying the interface. The intuitive approach is to reduce and simplify information, but we discovered that this actually impairs the quality of the decision. Our recommendation is that further investigation is required in order to find the “sweet spot” where understandability and comprehensiveness are maximised

• 320.
Stevens Institute of Technology, Hoboken, NJ, USA.
The University of British Columbia, Okanagan Campus, Kelowna, BC, Canada. Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013). The University of British Columbia, Okanagan Campus, Kelowna, BC, Canada.
Trajectory Optimization for Cooperative Dual-Band UAV Swarms2018Inngår i: 2018 IEEE Global Communications Conference (GLOBECOM 2018), IEEE, 2018Konferansepaper (Fagfellevurdert)

Unmanned aerial vehicles (UAVs) have gained a lot of popularity in diverse wireless communication fields. They can act as high- altitude flying relays to support communications between ground nodes due to their ability to provide line-of- sight links. With the flourishing Internet of Things, several types of new applications are emerging. In this paper, we focus on bandwidth hungry and delay-tolerant applications where multiple pairs of transceivers require the support of UAVs to complete their transmissions. To do so, the UAVs have the possibility to employ two different bands namely the typical microwave and the high-rate millimeter wave bands. In this paper, we develop a generic framework to assign UAVs to supported transceivers and optimize their trajectories such that a weighted function of the total service time is minimized. Taking into account both the communication time needed to relay the message and the flying time of the UAVs, a mixed non-linear programming problem aiming at finding the stops at which the UAVs hover to forward the data to the receivers is formulated. An iterative approach is then developed to solve the problem. First, a mixed linear programming problem is optimally solved to determine the path of each available UAV. Then, a hierarchical iterative search is executed to enhance the UAV stops' locations and reduce the service time. The behavior of the UAVs and the benefits of the proposed framework are showcased for selected scenarios.

• 321. Ghiglieri, Marco
Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013). TU Darmstadt.
Exploring Consumers' Attitudes of Smart TV Related Privacy Risks2017Inngår i: Human Aspects of Information Security, Privacy and Trust: 5th International Conference, HAS 2017, Held as Part of HCI International 2017, Vancouver, BC, Canada, July 9-14, 2017, Proceedings, Cham: Springer, 2017, Vol. 10292, s. 656-674Konferansepaper (Fagfellevurdert)
• 322.
Czech Acad Sci, Inst Math, Prague, Czech Republic.
Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013). Univ Freiburg, Inst Math. Charles Univ Prague, Czech republic. Czech Tech Univ; Univ South Bohemia, Czech republic.
Embeddings of Lorentz-type spaces involving weighted integral means2017Inngår i: Journal of Functional Analysis, ISSN 0022-1236, E-ISSN 1096-0783, Vol. 273, nr 9, s. 2939-2980Artikkel i tidsskrift (Fagfellevurdert)

We solve the problem of characterizing weights on (0, infinity) for which the inequality involving two possibly different general inner weighted means (integral(infinity)(0)(integral(t)(0)f*(s)(m2)u(2)(s)ds)(p2/m2) w(2)(t)dt)(1/p2) <= C(integral(infinity)(0)(integral(t)(0)f*(s)(m2)u(1)(s)ds)(p1/m1) w(1)(t)dt)(1/p1) holds, where p(1), p(2), m(1), m(2) is an element of (0, infinity) and p(2) > m(2). The proof is based on a new approach combining duality techniques with sharp weighted estimates for iterated integral and supremum operators. (C) 2017 Elsevier Inc. All rights reserved.

• 323.
Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013). Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013). Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013). Zhejiang Univ, China.
NFV-Inspector: A Systematic Approach to Profile and Analyze Virtual Network Functions2018Inngår i: 2018 IEEE 7th International Conference on Cloud Networking (CloudNet), IEEE, 2018, s. 1-7Konferansepaper (Fagfellevurdert)

Network Function Virtualization (NFV) focuses on decoupling network functions from proprietary hardware (i.e., middleboxes) by leveraging virtualization technology. Combining it with Software Defined Networking (SDN) enables us to chain network services much easier and faster. The main idea of using these technologies is to consolidate several Virtual Network Functions (VNFs) into a fewer number of commodity servers to reduce costs, increase VNFs fluidity and improve resource efficiency. However, the resource allocation and placement of VNFs in the network is a multifaceted decision problem that depends on many factors, including VNFs resource demand characteristics, arrival rate, configuration of underlying infrastructure, available resources and agreed Quality of Services (QoS) in Service Level Agreements (SLAs). This paper presents a bottom-up open-source NFV analysis platform (NFV-Inspector) to (1) systematically profile and classify VNFs based on resource capacities, traffic demand rate, underlying system properties, placement of VNFs in the network, etc. and (2) extract/calculate the correlation among the QoS metrics and resource utilization of VNFs. We evaluated our approach using an emulated virtual Evolved Packet Core platform (Open5GCore) to showcase how complex relation among various NFV service chains can be systematically profiled and analyzed.

• 324.
Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013). Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013). R&D Technology and Industry, Ericsson, Sweden.
Automated Analysis and Profiling of VirtualNetwork Functions: the NFV-Inspector Approach2018Inngår i: 2018 IEEE Conference on Network Function Virtualization and Software Defined Networks (NFV-SDN), IEEE, 2018Konferansepaper (Fagfellevurdert)

Discovering insights about Virtual Network Function (VNFs) resource demand characteristics will enable cloud vendors to optimize their underlying Network Function Virtualization (NFV) system orchestration and dramatically mitigate CapEx and OpEx spendings. However, analyzing large-scale NFV systems, especially in mobile network environments, is a challenging task and requires tailor-made approaches for each particular application. In this demo, we showcase NFV-Inspector, an open source and extensible VNF analysis platform that is capable of systematically benchmark and profile NFV deployments. Based on its pluggable framework, NFV-Inspector classifies VNFs resource demand characteristics and correlate their Key Performance Indicators (KPIs) with system-level Quality of Service (QoS) measurements.

• 325.
Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
The discriminant 10 Shimura curve and its associated Heun functions2016Inngår i: Bulletin of the London Mathematical Society, ISSN 0024-6093, E-ISSN 1469-2120, Vol. 48, s. 957-967Artikkel i tidsskrift (Fagfellevurdert)

The Shimura curve of discriminant 10 is uniformized by a subgroup of an arithmetic $(2,2,2,3)$ quadrilateral group. We derive the differential structure of the ring of modular forms for the Shimura curve and relate the ring generators to explicit Heun functions for the quadrilateral group. We also show that the Picard–Fuchs equation of the associated family of abelian surfaces has solutions that are modular forms. These results are used to completely describe the exceptional sets of the Heun functions, and we show how to find examples like $Hl\left(\frac{27}{2},\frac{7}{36}; \frac{1}{12},\frac{7}{12},\frac{2}{3},\frac{1}{2}; -\frac{96}{25}\right)=\frac{2^{1/2}5^{2/3}}{3^{4/3}}.$

• 326.
Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
Differential equations and expansions for quaternionic modular forms in the discriminant 6 case2012Inngår i: LMS Journal of Computation and Mathematics, ISSN 1461-1570, E-ISSN 1461-1570, Vol. 15, s. 385-399Artikkel i tidsskrift (Fagfellevurdert)

We study the differential structure of the ring of modular forms for the unit group of the quaternion algebra over Q of discriminant 6. Using these results we give an explicit formula for Taylor expansions of the modular forms at the elliptic points. Using appropriate normalizations we show that the Taylor coefficients at the elliptic points of the generators of the ring of modular forms are all rational and 6-integral. This gives a rational structure on the ring of modular forms. We give a recursive formula for computing the Taylor coefficients of modular forms at elliptic points and, as an application, give an algorithm for computing modular polynomials.

• 327.
Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
Symmetry methods and some nonlinear differential equations: Background and illustrative examples2017Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave

Differential equations, in particular the nonlinear ones, are commonly used in formulating most of the fundamental laws of nature as well as many technological problems, among others. This makes the need for methods in finding closed form solutions to such equations all-important. In this thesis we study Lie symmetry methods for some nonlinear ordinary differential equations (ODE). The study focuses on identifying and using the underlying symmetries of the given first order nonlinear ordinary differential equation. An extension of the method to higher order ODE is also discussed. Several illustrative examples are presented.

• 328.
University of Modena and Reggio Emilia, Italy.
Centre Tecnológic de Telecomunicacions de Catalunya, Spain. Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013). University of Modena and Reggio Emilia, Italy. University of Modena and Reggio Emilia, Italy. Centre Tecnológic de Telecomunicacions de Catalunya, Spain.
Adapting TCP Small Queues for IEEE 802.11 Networks2018Inngår i: 2018 IEEE 29Th Annual International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC), IEEE, 2018Konferansepaper (Fagfellevurdert)

In recent years, the Linux kernel has adopted an algorithm calledTCP Small Queues (TSQ) for reducing queueing latency by controlling buffering in the networking stack.This solution consists of a back-pressure mechanism that limitsthe number of TCP segments within the sender TCP/IP stack, waitingfor packets to actually be transmitted onto the wire beforeenqueueing further segments.Unfortunately, TSQ prevents the frameaggregation mechanism in the IEEE 802.11n/ac standards from achieving itsmaximum aggregation, because not enough packets are available in the queue to buildaggregates from, which severely limits achievable throughput over wirelesslinks.This paper demonstrates this limitation of TSQ in wireless networks and proposesControlled TSQ (CoTSQ), a solution that improves TSQ so that it controls the amountof data buffered while allowing the IEEE 802.11n/ac aggregation logic to fullyexploit the available channel and achieve high throughput. Results on a real testbed show that CoTSQ leadsto a doubling of throughput on 802.11n and up to an order of magnitudeimprovement in 802.11ac networks, with a negligible latency increase.

• 329.
Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap.
Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap.
Struktur på den digitala arbetsplatsen2017Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave

Begreppet den digitala arbetsplatsen kan ses som ett samlingsnamn för alla de verktyg och IT-system som används i det digitala arbetet. På den digitala arbetsplatsen behövs en intern kommunikationsstrategi för hur information ska hanteras för att effektivisera arbetet samt för att få en struktur i de digitala verktygen. Fabriken anser att intranätet är det verktyg som kopplar samman alla verktyg i den digitala arbetsplatsen.

Kommunikationsstrategierna beskriver var anställda kan hitta eller dela information inom verksamheten. Saknas en kommunikationsstrategi kan nackdelar som redundans, duplicerad information och svårigheter att hitta rätt information förekomma.

Målet med studien är att ta fram en intern kommunikationsstrategi samt se om intranätet kan bli navet i Fabrikens digitala arbetsplats. Kommunikationsstrategin har tagits fram genom informationsinsamling med hjälp av intervjuer och workshop. För att realisera kommunikationsstrategin var tanken att utveckla en Proof of Concept (PoC) för att visa Fabriken vilka möjligheter strategin innebär om intresse för vidareutveckling finns. Denna PoC utvecklades dock aldrig på grund av tidsbrist.

Studien resulterade i en kommunikationsstrategi samt förslag på förändringar på intranätet. Förändringarna omfattar bland annat intranätets tillgänglighet samt en lösning i form av en kunskapsbank.

• 330.
KTH Royal Institute of Tech. .
Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013). Princeton University. Princeton University. Princeton University.
The Effect of DNS on Tor´s Anonymity2017Inngår i: NDSS Symposium 2017, Internet society , 2017Konferansepaper (Fagfellevurdert)

• 331.
Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
Dell EMC. Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013). Mozilla. Celerway. University of Aberdeen, UK.. Celerway. University of Oslo, Norway. Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013). University of Oslo, Norway. Dell EMC. University of Aberdeen, UK.. Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013). Simula. FH Münster, Germany. Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013). University of Aberdeen, UK.. FH Münster, Germany. FH Münster, Germany. University of Oslo, Norway.
Deliverable D3.1 - Initial Report on the Extended Transport System2017Rapport (Fagfellevurdert)

The NEAT System offers an enhanced API for applications that disentangles them from the actual transport protocol being used. The system also enables applications to communicate their service requirements to the transport system in a generic, transport-protocol independent way. Moreover, the architecture of the NEAT System promotes the evolution of new transport services. Work Package 3 (WP3) enhances and extends the core parts of the NEAT Transport. Efforts have been devoted to developing transport-protocol mechanisms that enable a wider spectrum of NEAT Transport Services, and that assist the NEAT System in facilitating several of the commercial use cases. Work has also started on the development of optimal transport-selection mechanisms; mechanisms that enable for the NEAT System to make optimal transport selections on the basis of application requirements and network measurements. Lastly, another research activity has been initiated on how to use SDN to signal application requirements to routers, switches, and similar network elements. This document provides an initial report on all these WP3 activities—both on completed and on near-termplanned work.

• 332.
Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
Dell EMC. Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013). Simula. Celerway. University of Aberdeen, UK.. Celerway. University of Oslo, Norway. Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013). Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013). University of Aberdeen, UK.. Simula. Celerway. FH Münster, Germany. CISCO.
Deliverable D3.3 - Extended Transport System and Transparent Support of Non-NEAT Applications2017Rapport (Fagfellevurdert)

This deliverable summarises and concludes our work in Work Package 3 (WP3) to extend the transport services provided by the NEAT System developed in Work Package 2, and to enable non-NEAT applications to harness the transport services offered by NEAT. We have demonstrated how a policy- and information-based selection of transport protocol by NEAT could provide a more efficient transport service for web applications. The information on which NEAT makes its transport selection decisions resides in the Characteristics Information Base (CIB). The CIB is populated by various CIB sources, and in WP3 we have designed, implemented, and evaluated various CIB sources, including meta data from mobile broadband networks, passive measurements, IPv6 Provisioning Domain protocols and the Happy Eyeballs mechanism, which caches the outcome of its connection attempts. A key property of NEAT is that it not only “vertically” decouples applications from transport protocols, but also “horizontally”. Particularly, it enables applications to harness information about resource availability and policies from Software Defined Networking (SDN) controllers in managed networks, without these applications actually being SDN-aware. To extend the use of NEAT to non-NEAT applications, we have implemented a BSDcompatible sockets API on top of NEAT and a NEAT proxy that intercepts and replaces standard TCP connections with NEAT flows, i.e., with the transport solutions deemed most appropriate by NEAT.We have also proposed a way for non-NEAT applications to make use of NEAT through the deployment of NEAT-enabled virtual appliances in SDN-controlled networks: connections from these applications are routed via an SDN-controlled proxy that terminates the original connection and replaces it with a NEAT-selected connection.

• 333.
Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013). Ericsson AB, Stockholm, Sweden.
Using Concurrent Multipath Transfer to Improve the SCTP Startup Behavior for PSTN Signaling Traffic2014Inngår i: 2014 28TH INTERNATIONAL CONFERENCE ON ADVANCED INFORMATION NETWORKING AND APPLICATIONS WORKSHOPS (WAINA) / [ed] Barolli, L; Li, KF; Enokido, T; Xhafa, F; Takizawa, M, IEEE, 2014, s. 772-778Konferansepaper (Fagfellevurdert)

Although latency in the Internet has gained much attention in the research community, the latency issues of mobile control signaling have received less attention, and this all the while many telecom operators are experiencing a several-hundred percent increase in signaling traffic over only a couple of years. We believe one way to address both the latency and increased signaling load of mobile networks, is to exploit concurrent transfer of signaling traffic over several paths a.k.a. concurrent multipath transfer. This paper studies whether or not SCTP extended with concurrent multipath transfer (CMT-SCTP) could provide a faster startup behavior than standard SCTP. The paper complements previous work on CMT-SCTP, and extends it to PSTN signaling traffic. The paper suggests that CMT-SCTP could give a faster startup behavior over paths with similar bandwidths and round-trip times, but that its behavior is sensitive to differences in round-trip time between the paths. Moreover, the paper suggests that provided CMT-SCTP is configured with large enough send and receive buffers, it could provide a faster startup behavior than standard SCTP over a multipath association, in spite of some of the paths having a packet-loss rate of several percent.

• 334.
Karlstads universitet, Fakulteten för ekonomi, kommunikation och IT, Avdelningen för datavetenskap. Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap.
Karlstads universitet, Fakulteten för ekonomi, kommunikation och IT, Avdelningen för datavetenskap. Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap.
A First Study on Using MPTCP to Reduce Latency for Cloud Based Mobile Applications2015Inngår i: 2015 IEEE SYMPOSIUM ON COMPUTERS AND COMMUNICATION (ISCC), IEEE, 2015, s. 64-69Konferansepaper (Fagfellevurdert)

Currently, Multipath TCP (MPTCP) – a modifica- tion to standard TCP that enables the concurrent use of several network paths in a single TCP connection – is being standardized by IETF. This paper provides a comprehensive evaluation of the use of MPTCP to reduce latency and thus improve the quality of experience or QoE for cloud-based applications. In particular, the paper considers the possible reductions in latency that could be obtained by using MPTCP and multiple network paths between a cloud service and a mobile end user. To obtain an appreciation of the expected latency performance for different types of cloud traffic, three applications are studied, Netflix, Google Maps, and Google Docs, representing typical applications generating high-, mid-, and low-intensity traffic. The results suggest that MPTCP could provide significant latency reductions for cloud applications, especially for applications such as Netflix and Google Maps. Moreover, the results suggest that MPTCP offers a reduced latency despite a few percent packet loss, and in spite of limited differences in the round-trip times of the network paths in an MPTCP connection. Still, larger differences in the round-trip times seem to significantly increase the application latency, especially for Netflix, Google Maps, and similar applications. Thus, to become an even better alternative to these applications, this paper suggests that the MPTCP packet scheduling policy should be changed: Apart from the round-trip times of the network paths in a connection, it should also consider the difference in round-trip time between the network paths.

• 335.
Karlstads universitet, Fakulteten för ekonomi, kommunikation och IT.
Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap.
A Survey of TCP-Friendly Congestion Control Mechanisms for Multimedia Traffic2003Rapport (Annet vitenskapelig)

The stability and performance of the Internet to date have in a large part been due tothe congestion control mechanism employed by TCP. However, while the TCP congestioncontrol is appropriate for traditional applications such as bulk data transfer, it hasbeen found less than ideal for multimedia applications. In particular, audio and videostreaming applications have difficulties managing the rate halving performed by TCP inresponse to congestion. To this end, the majority of multimedia applications use eithera congestion control scheme which reacts less drastic to congestion and therefore oftenis more aggressive than TCP, or, worse yet, no congestion control whatsoever. Sincethe Internet community strongly fears that a rapid deployment of multimedia applicationswhich do not behave in a fair and TCP-friendly manner could endanger the currentstability and performance of the Internet, a broad spectrum of TCP-friendly congestioncontrol schemes have been proposed. In this report, a survey over contemporary proposalsof TCP-friendly congestion control mechanisms for multimedia traffic in the Internetis presented. A classification scheme is outlined which shows how the majority of theproposed congestion control schemes emanate from a relatively small number of designprinciples. Furthermore, we illustrate how these design principles have been applied ina selection of congestion control scheme proposals and actual transport protocols.

• 336.
Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013). University of Aberdeen, UK.. University of Oslo, Norway. Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013). University of Oslo, Norway. Simula. FH Münster, Germany. FH Münster, Germany. FH Münster, Germany. University of Oslo, Norway.
Deliverable D3.2 - Final Report on Transport Protocol Enhancements2017Rapport (Fagfellevurdert)

This deliverable provides a final report on the work on transport protocol enhancements done inWork Package 3. First, we report on the extensions made to the SCTP protocol that turn it into a viable alternative to TCP and allow to deliver a lower-latency transport service. Next, we describe our work to develop a framework for providing a deadline-aware, less-than-best-effort transport service, targeting background traffic and thus addressing requirements on NEAT from the EMC use case. We also present our efforts to design and implement a latency-aware scheduler for MPTCP, which enables NEAT to offer a transport service that meets the needs of latency-sensitive applications, and that efficiently utilises available network resources. Lastly, this document informs on our work on coupled congestion control for TCP, a mechanism that treats a bundle of parallel TCP flows between the same pair of hosts as a single unit. By efficiently multiplexing concurrent TCP flows, our coupled congestion control alleviates the effects of queueing, and tends to result in a more efficient usage of available bandwidth, where the flows’ aggregate capacity share can be apportioned based on application preferences.

• 337.
Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
Karlstads universitet, Fakulteten för ekonomi, kommunikation och IT, Centrum för HumanIT. Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013). University of Aberdeen. University of Aberdeen. Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013). Simula Research Lab.
NEAT - A New, Evolutive API and Transport-Layer Architecture for the Internet2016Inngår i: 12th Swedish National Computer Networking Workshop (SNCNW 2016), Sundsvall, Sweden., 2016Konferansepaper (Annet vitenskapelig)

There is a growing concern that the Internet trans- port layer has become ossified in the face of emerging novel applications, and that further evolution has become very difficult. This paper identifies requirements for a new transport layer and then proposes a conceptual architecture, the NEAT system, that we believe is both flexible and evolvable. Applications interface the NEAT system through an enhanced user API that decouples them from the operation of the transport protocols and the network features being used. In particular, applications provide the NEAT system with information about their traffic requirements, pre- specified policies, and measured network conditions. On the basis of this information, the NEAT system establishes and configures appropriate connections.

• 338.
Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
University of Aberdeen, Aberdeen, U.K. University of Aberdeen, Aberdeen, U.K. Simula Research Laboratory, Oslo, Norway. Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013). Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
Towards a Flexible Internet Transport Layer Architecture2016Inngår i: The 22nd IEEE International Symposium on Local and Metropolitan Area Networks (LANMAN), Rome, Italy, June 2015 / [ed] IEEE, IEEE, 2016Konferansepaper (Fagfellevurdert)

There is a growing concern that the Internet trans- port layer has stagnated and become less adaptive to the requirements imposed by new applications, and that further evolution has become very difficult. This is because a fundamental assumption no longer holds: it can no longer be assumed that the transport layer is only in the scope of end-hosts. The success of TCP and UDP and the ubiquity of middleboxes have led to ossification of both the network infrastructure and the API presented to applications. This has led to the development of workarounds, and a range of point solutions that fail to cover many facets of the problem. To address this issue, this paper identifies requirements for a new transport layer and then proposes a conceptual architecture that we argue is both flexible and evolvable. This new architecture requires that applications interface to the transport at a higher abstraction level, where an application can express communication preferences via a new richer API. Protocol machinery can use this information to decide which of the available transport protocols is used. By placing the protocol machinery in the transport layer, the new architecture can allow for new protocols to be deployed and enable evolution of the transport layer.

• 339.
University of Bremen, Germany.
Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
Brief Introduction to Damage Mechanics and its Relation to Deformations2018Inngår i: Mathematical Analysis of Continuum Mechanics and Industrial Applications II / [ed] P. VanMeurs, M Kimura, H Notsu, Springer, 2018, Vol. 30, s. 115-124Konferansepaper (Fagfellevurdert)

We discuss some principle concepts of damage mechanics and outline a possibility to address the open question of the damage-to-deformation relation by suggesting a parameter identification setting. To this end, we introduce a variable motivated by the physical damage phenomenon and comment on its accessibility through measurements. We give an extensive survey on analytic results and present an isotropic irreversible partial damage model in a dynamic mechanical setting in form of a second order hyperbolic equation coupled with an ordinary differential equation for the damage evolution. We end with a note on a possible parameter identification setting.

• 340.
Washington Univ, Dept Comp Sci & Engn, St Louis, MO 63110 USA..
Washington Univ, Dept Comp Sci & Engn, St Louis, MO 63110 USA.. Qatar Univ, Dept Comp Sci & Engn, Doha, Qatar.. Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
The P-ART framework for placement of virtual network services in a multi-cloud environment2019Inngår i: Computer Communications, ISSN 0140-3664, E-ISSN 1873-703X, Vol. 139, s. 103-122Artikkel i tidsskrift (Fagfellevurdert)

Carriers' network services are distributed, dynamic, and investment intensive. Deploying them as virtual network services (VNS) brings the promise of low-cost agile deployments, which reduce time to market new services. If these virtual services are hosted dynamically over multiple clouds, greater flexibility in optimizing performance and cost can be achieved. On the flip side, when orchestrated over multiple clouds, the stringent performance norms for carrier services become difficult to meet, necessitating novel and innovative placement strategies. In selecting the appropriate combination of clouds for placement, it is important to look ahead and visualize the environment that will exist at the time a virtual network service is actually activated. This serves multiple purposes - clouds can be selected to optimize the cost, the chosen performance parameters can be kept within the defined limits, and the speed of placement can be increased. In this paper, we propose the P-ART (Predictive-Adaptive Real Time) framework that relies on predictive-deductive features to achieve these objectives. With so much riding on predictions, we include in our framework a novel concept-drift compensation technique to make the predictions closer to reality by taking care of long-term traffic variations. At the same time, near real-time update of the prediction models takes care of sudden short-term variations. These predictions are then used by a new randomized placement heuristic that carries out a fast cloud selection using a least-cost latency-constrained policy. An empirical analysis carried out using datasets from a queuing-theoretic model and also through implementation on CloudLab, proves the effectiveness of the PART framework. The placement system works fast, placing thousands of functions in a sub-minute time frame with a high acceptance ratio, making it suitable for dynamic placement. We expect the framework to be an important step in making the deployment of carrier-grade VNS on multi-cloud systems, using network function virtualization (NFV), a reality.

• 341.
Glasgow University, Scotland. Glasgow University, Scotland. Tech Univ Darmstadt, Darmstadt, Germany. Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap. Tech Univ Darmstadt, Darmstadt, Germany. University Tokyo, Japan. Karlsruhe Inst Technol, Germany.
ZeTA - Zero-Trust Authentication: Relying on Innate Human Ability, not Technology2016Inngår i: 2016 IEEE European Symposium on Security and Privacy (EuroS&P), IEEE, 2016, s. 357-371Konferansepaper (Fagfellevurdert)

Reliable authentication requires the devices and channels involved in theprocess to be trustworthy; otherwise authentication secrets can easily becompromised. Given the unceasing efforts of attackers worldwide suchtrustworthiness is increasingly not a given. A variety of technicalsolutions, such as utilising multiple devices/channels and verificationprotocols, has the potential to mitigate the threat of untrustedcommunications to a certain extent. Yet such technical solutions make twoassumptions: (1) users have access to multiple devices and (2) attackerswill not resort to hacking the human, using social engineering techniques.In this paper, we propose and explore the potential of using human-basedcomputation instead of solely technical solutions to mitigate the threat ofuntrusted devices and channels. ZeTA (Zero  Trust Authentication on untrusted channels) has the potentialto allow people to authenticate despite compromised channels orcommunications and easily observed usage. Our contributions are threefold:(1) We propose the ZeTA protocol with a formal definition and securityanalysis that utilises semantics and human-based computation to amelioratethe problem of untrusted devices and channels.(2) We  outline a security analysis to assess the envisaged performance ofthe proposed authentication protocol.(3) We report on  a  usability study that explores the viability of relyingon human computation in this context.

• 342. Gutmann, Andreas
Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
Nudging Bank Account Holders Towards More Secure PIN Management2015Inngår i: Journal of Internet Technology and Secured Transactions, ISSN 1748-569X, Vol. 4, s. 380-386Artikkel i tidsskrift (Fagfellevurdert)

The memorability of PINs is an enduring security issue. This is especially pertinent in the context of banking, where technical systems evolve more slowly than in other contexts (e.g. many mobile phone operating systems have adopted alternative authentication mechanisms). Banking customers who struggle to memorise all their PINs often record them, sometimes insecurely, flying in the face of advice from their banks. Banks respond to memorisation difficulties by permitting customers to change their PINs. The reality is that both recording and changing unwittingly weakens the mechanism by increasing predictability. Yet trying to forbid these coping strategies is futile. It is far better to acknowledge the prevalence of such behaviours and to try to nudge people towards more secure PIN management. In this paper, we suggest a way of achieving this.

• 343.
Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
Lärares kompetensutveckling och digitalisering av matematikundervisning: En enkätstudie om hur lågstadielärare kompetensutvecklar sig för att bemöta digitalisering av matematikundervisning2018Independent thesis Advanced level (degree of Master (One Year)), 20 poäng / 30 hpOppgave

Syftet med denna studie var att undersöka hur lågstadielärare fortbildade sig för att kunna möta de krav som ställs på dem vad det gäller digitalisering av matematikundervisning samt hur detta hänger samman med deras upplevda kompetens samt användning av IKT i matematikundervisningen.För att uppfylla syftet samlades studiens empiriska data in via en webbaserad enkätundersökning, som besvarades av 76 lågstadielärare.

Resultatet visade att de flesta lågstadielärarna kompetensutvecklade sig på en mängd varierande sätt såväl på den formella arenan som på den informella arenan. Dessutom framkom det i resultatet att de lågstadielärare som fortbildade sig via webbaserade kompetensutvecklingssätt på den formella arenan i kombination med alla sätt på den informella arenan, högst uppskattade sina kunskaper inom delområdena TCK, TPK och TPACK samt använde IKT på flest sätt inom flest matematikområden. Vidare framkom det också att majoriteten av lågstadielärare fortbildade sig på alla sätt på båda arenor.Dessa lågstadielärare upplevde ha höga kunskaper i alla tre delområden, men deras IKT-användning låg på genomsnittsnivån för studiens samtliga kompetensutvecklingsformer.

• 344.
Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap.
Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap.
Documentation and implementation of interfaces for an embedded platform2013Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave

Using a new platform can be challenging, especially with relatively newly released platform and developer equipment. Difficulties and problems can arise during development from both hardware and software, some problems can be solved but sometimes help must be requested from the developers of the products.

The consulting firm Altran in Karlstad has been dealing with this and has developed embedded software used in industrial welders for cars. There have been some uncertainty during their work, which has given birth to this project. The purpose of this project was to reconstruct and document Altran's initial development process, to make the process faster and easier for new developers. Besides the reconstruction, a discovery of unused features and components also became an important part of this project.

The project has resulted in a documentation of various interfaces, an clock in system application called "Personnel Interactive Display and Educator", and a safe update application for the system.

• 345.
Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013). Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
Rate Measurement Over Short Time Scales inStationary Cellular Receivers2019Inngår i: Proceedings of the 3rd Workshop on Mobile Network Measurement (MNM 2019), Paris, France, June 2019, 2019Konferansepaper (Fagfellevurdert)

An increasing number of cellular congestion controlalgorithms (CCAs) are relying on measurements of the deliveryrate observed at the receiver. Accordingly, early detection ofchanges in the receiver’s rate would improve the performanceof such algorithms. Rate measurements over short time intervalscould allow fast detection of change in the rate observed bythe upper layers of a cellular receiver. However, for cellularreceivers, upper-layer rate measurements over short time scalesproduce unreliable results due to the effect of underlying lowerlayer mechanisms such as scheduling and retransmissions. In thispaper, we introduce a rate estimation approach that reduces thevariability observed in short time scale receiver rate measurementsand allows faster rate change detection. We also integratean adaptive mechanism to improve online measurements overdifferent time scales.

• 346.
Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013). Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013). Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
Rate Change Detection in Stationary Cellular Nodes2019Inngår i: Proceedings of the Fifteenth Swedish National Computer NetworkingWorkshop (SNCNW), Luleå, Sweden. 4-5 June, 2019Konferansepaper (Fagfellevurdert)

An increasing number of cellular congestion controlalgorithms (CCAs) are relying on measurements of the deliveryrate observed at the receiver. Accordingly, early detection ofchanges in the receiver’s rate would improve the performanceof such algorithms. Rate measurements over short time intervalscould allow fast detection of change in the rate observed bythe upper layers of a cellular receiver. However, upper layerrate measurements for cellular receivers over a short time scaleproduce unreliable results due to the effect of underlying lowerlayer mechanisms. In this paper, we introduce a rate estimationapproach that reduces the variability observed in short timescale receiver rate measurements and allows faster rate changedetection.

• 347.
Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013). Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013). Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013). University of the Basque Country. University of the Basque Country. Kristianstad University.
Evaluation of the Impact of TCP BBR Startup on CUBIC Traffic2018Inngår i: The Fourteenth Swedish National Computer Networking Workshop (SNCNW) 2018, 2018Konferansepaper (Annet vitenskapelig)
• 348.
Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap.
Identifiering av särbegåvade elever: Identifiering av generellt särbegåvade elever och särbegåvade elever inom ämnet matematik.2016Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave

Studiens syfte är att få ta del av pedagogernas syn på hur de ser på sin förmåga att identifiera särbegåvade elever och matematiskt särbegåvade elever. Om de tycker att de har goda förutsättningar för att kunna identifiera dessa elever eller om de upplever något hinder i sin förmåga att identifiera dem. Jag har valt att använda mig utav en enkätstudie för att få svar på mina frågor. Webbenkäten är skickad till 3 små kommuner och jag valde enkäter istället för intervjuer för att jag ville få en större spridning och fler olika sorters pedagoger som svarade.

Studien visar att många av pedagogerna vet vad begreppet särbegåvad innebär men att de själva känner att de har för lite kunskap inom ämnet.

• 349.
Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap.
mAPPematik: Matematiskt innehåll i surfplattors appar för barn i yngre åldrar2014Independent thesis Advanced level (professional degree), 10 poäng / 15 hpOppgave

Denna undersökning är gjord för att studera de appar som kan laddas ned och användas på surfplattor, då surfplattor blir ett mer vanligt förekommande pedagogiskt verktyg. Denna studie fokuserar på att granska appar som kan användas i matematikundervisningen för de yngre eleverna. Surfplattor köps in mer och mer till skolorna, då de är billiga och enkla verktyg att använda. Applikationerna som köps eller laddas ner till surfplattorna är billiga, lättillgängliga och utbudet är omfattande. Dock är utbildningsvetenskaplig forskning om surfplattor och dess applikationer inte så omfattande.

I studien diskuteras vidare hur de matematikappar som granskats kan användas i matematikundervisningen kopplat till ett tydligt mål och syfte med användandet. De förmågor och centralt innehåll som studien fokuserar på är elevernas möjlighet att utveckla taluppfattning, likhetstecknets betydelse, räkne reglerna och tallinjen. Studien visar att alla de 13 appar som ingår i undersökningen kan användas i matematikundervisningen för färdighetsträning, men att bara 3 av apparna beskriver uppgifterna så pass utförligt att de kan användas redan från början i inlärningen.

• 350.
Unabhängiges Landeszentrum für Datenschutz (ULD), Kiel, Germany.
Kosta, EleniTilburg Institute for Law, Technology and Society (TILT), Tilburg University, Tilburg, The Netherlands.Nai-Fovino, IgorEuropean Commission - Joint Research Centre, Ispra, Italy.Fischer-Hübner, SimoneKarlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), Institutionen för matematik och datavetenskap (from 2013).
Privacy and Identity Management: The Smart Revolution2018Konferanseproceedings (Fagfellevurdert)

This book contains selected papers presented at the 12th IFIP WG 9.2, 9.5, 9.6/11.7, 11.6/SIG 9.2.2 International Summer School on Privacy and Identity Management, held in Ispra, Italy, in September 2017.The 12 revised full papers, 5 invited papers and 4 workshop papers included in this volume were carefully selected from a total of 48 submissions and were subject to a three-phase review process. The papers combine interdisciplinary approaches to bring together a host of perspectives: technical, legal, regulatory, socio-economic, social, societal, political, ethical, anthropological, philosophical, and psychological. They are organized in the following topical sections: privacy engineering; privacy in the era of the smart revolution; improving privacy and security in the era of smart environments; safeguarding personal data and mitigating risks; assistive robots; and mobility and privacy.

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