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  • 21551.
    Wang, Kun
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Barkowsky, M.
    Image and Video-Communication (IVC) Research Group, LUNAM Université, Université de Nantes, Polytech Nantes, 44306 Nantes Cedex 3, France.
    Brunnström, Kjell
    Acreo AB, Department of NetLab, Electrum 236, Kista, 16440, Sweden.
    Sjöström, Mårten
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Cousseau, R.
    Image and Video-Communication (IVC) Research Group, LUNAM Université, Université de Nantes, Polytech Nantes, 44306 Nantes Cedex 3, France.
    Le Callet, P.
    Image and Video-Communication (IVC) Research Group, LUNAM Université, Université de Nantes, Polytech Nantes, 44306 Nantes Cedex 3, France.
    Perceived 3D TV transmission quality assessment: Multi-laboratory results using absolute category rating on quality of experience scale2012In: IEEE transactions on broadcasting, ISSN 0018-9316, E-ISSN 1557-9611, Vol. 58, no 4, p. 544-557Article in journal (Refereed)
    Abstract [en]

    Inspired by the rapidly increasing popularity of 3D movies, there is an industrial push for 3DTV services to the home. One important factor for the success and acceptance by the viewers is a positive quality of experience (QoE) of the new service when delivered. The questions of how to efficiently deliver 3DTV service to the home, and how to evaluate the visual quality perceived by end users are a recent research focus. We have investigated users' experience of stereoscopic 3D video quality by preparing two subjective assessment datasets. The first dataset aimed at the evaluation of efficient transmission in the transmission error free case, while the second focused on error concealment. A total of three subjective assessments, two for first dataset and one for the second, were performed using the Absolute Category Rating with Hidden unimpaired Reference video (ACR-HR) method. The experimental setup allows to show that the ACR-HR subjective method provides repeatable results across labs and across conditions for video quality. It was also verified that MVC is more efficient than H.264 simulcast coding. Furthermore it was discovered that based on the same level of quality of experience spatial down-sampling may lead to better bitrate efficiency while temporal down-sampling is not acceptable. When network impairments occur, traditional error 2D concealment methods need to be reinvestigated as they were outperformed by displaying the same view for both eyes (switching to 2D presentation). © 2012 IEEE.

  • 21552.
    Wang, Kun
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Barkowsky, Marcus
    Dept. of Image and Video Communication, IRCCyN, University of Nantes, France.
    Cousseau, Romain
    Dept. of Image and Video Communication, IRCCyN, University of Nantes, France.
    Brunnström, Kjell
    Dept. of NetLab: IPTV, Video and Display Quality, Acreo AB, Sweden.
    Olsson, Roger
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Le Callet, Patrick
    Dept. of Image and Video Communication, IRCCyN, University of Nantes, France.
    Sjöström, Mårten
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Subjective evaluation of HDTV stereoscopic videos in IPTV scenarios using absolute category rating2011In: Proceedings of SPIE - The International Society for Optical Engineering Volume 7863, 2011 / [ed] A. J. Woods, N. S. Holliman, and N. A. Dodgson, SPIE - International Society for Optical Engineering, 2011, p. Art. no. 78631T-Conference paper (Refereed)
    Abstract [en]

    Broadcasting of high definition (HD) stereobased 3D (S3D) TV are planned, or has already begun, in Europe, the US, and Japan. Specific data processing operations such as compression and temporal and spatial resampling are commonly used tools for saving network bandwidth when IPTV is the distribution form, as this results in more efficient recording and transmission of 3DTV signals, however at the same time it inevitably brings quality degradations to the processed video. This paper investigated observers quality judgments of state of the art video coding schemes (simulcast H.264/AVC or H.264/MVC), with or without added temporal and spatial resolution reduction of S3D videos, by subjective experiments using the Absolute Category Rating method (ACR) method. The results showed that a certain spatial resolution reduction working together with high quality video compressing was the most bandwidth efficient way of processing video data when the required video quality is to be judged as "good" quality. As the subjective experiment was performed in two different laboratories in two different countries in parallel, a detailed analysis of the interlab differences was performed

  • 21553.
    Wang, Kun
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information and Communication systems. Dept. of NetLab: Visual Media Quality, Swedish ICT-Acreo AB, Sweden .
    Brunnström, Kjell
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information and Communication systems. Dept. of NetLab: Visual Media Quality, Swedish ICT-Acreo AB, Sweden .
    Barkowsky, M.
    Dept. of Image and Video Communication, IRCCyN, University of Nantes, France .
    Urvoy, M.
    Dept. of Image and Video Communication, IRCCyN, University of Nantes, France .
    Sjöström, Mårten
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information and Communication systems.
    Le Callet, P.
    Dept. of Image and Video Communication, IRCCyN, University of Nantes, France .
    Tourancheau, Sylvain
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information and Communication systems.
    Andren, B.
    Dept. of NetLab: Visual Media Quality, Swedish ICT-Acreo AB, Sweden .
    Stereoscopic 3D video coding quality evaluation with 2D objective metrics2013In: Proceedings of SPIE - The International Society for Optical Engineering, 2013, p. Art. no. 86481L-Conference paper (Refereed)
    Abstract [en]

    The 3D video quality is of highest importance for the adoption of a new technology from a user's point of view. In this paper we evaluated the impact of coding artefacts on stereoscopic 3D video quality by making use of several existing full reference 2D objective metrics. We analyzed the performance of objective metrics by comparing to the results of subjective experiment. The results show that pixel based Visual Information Fidelity metrics fits subjective data the best. The 2D stereoscopic video quality seems to have dominant impact on the coding artefacts impaired stereoscopic videos.

  • 21554.
    Wang, L.
    et al.
    Department of Electronic Engineering and Information Science, University of Science and Technology of China, Hefei 230027, China.
    Wang, G.
    Department of Electronic Engineering and Information Science, University of Science and Technology of China, Hefei 230027, China.
    Sidén, Johan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Design of fragment-type isolation structures for MIMO antennas2014In: Progress In Electromagnetics Research C, ISSN 1937-8718, E-ISSN 1937-8718, Vol. 52, p. 71-82Article in journal (Refereed)
    Abstract [en]

    Fragment structure should find its application in acquiring high isolation between multiple-input multiple-output (MIMO) antennas. By gridding a design space into fragment cells, a fragment-type isolation structure can be constructed by metalizing some of the fragment cells. For MIMO isolation design, cells to be metalized can be selected by optimization searching scheme with objectives such as isolation, return losses, and even radiation patterns of MIMO antennas. Due to the exibility of fragment-type isolation structure, fragment-type structure has potentials to yield isolation higher than canonical isolation structures. In this paper, multi-objective evolutionary algorithm based on decomposition combined with genetic operators (MOEA/D-GO) is applied to design fragment-type isolation structures for MIMO patch antennas and MIMO PIFAs. It is demonstrated that isolation can be improved to different extents by using fragment-type isolation design. Some technique aspects related to the fragment-type isolation design, such as effects of fragment cell size, design space, density of metal cells, and efficiency consideration, are further discussed.

  • 21555.
    Wang, Linlin
    Mid Sweden University, Faculty of Human Sciences, Department of Education.
    Vägen genom den svenska skolan för ungdomar med utländsk härkomst2013Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
  • 21556.
    Wang, Lu
    et al.
    University of Science and Technology of China, Hefei, China.
    Liu, Ting
    University of Science and Technology of China, Hefei, China.
    Sidén, Johan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Wang, Gang
    University of Science and Technology of China, Hefei, China; Key Laboratory of Electromagnetic Space Information, Chinese Academy of Sciences, Hefei, China.
    Design of Chipless RFID Tag by Using Miniaturized Open-Loop Resonators2018In: IEEE Transactions on Antennas and Propagation, ISSN 0018-926X, E-ISSN 1558-2221, Vol. 66, no 2, p. 618-626, article id 8186235Article in journal (Refereed)
    Abstract [en]

    In this paper, an open-loop resonator with fragment-loading structure is used for the first time in the design of radar cross section-based chipless radio-frequency identification (RFID) tag. By optimizing the distribution of fragment patches in an open loop, a microstrip open-loop resonator can be miniaturized so that the data capacity of the chipless RFID tag designed using such a miniaturized loop resonator can be significantly increased. Moreover, the resonant frequency of the fragment-loaded resonator can be adjusted conveniently by removing or disconnecting some fragment patches, which provides great flexibility for data encoding of the chipless RFID tag. The proposed chipless RFID tag with miniaturized open-loop resonators is designed and tested and can acquire 3.56 bits per resonator and a coding density of approximately 745.1bits/λg 2. Several experimental results validate the proposed design as well as its implementation in a realistic environment.

  • 21557.
    Wang, Lu
    et al.
    University of Science and Technology of China, Hefei, China.
    Wang, Gang
    University of Science and Technology of China, Hefei, China.
    Sidén, Johan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    High-performance tight coupling microstrip directional coupler with fragment-type compensated structure2017In: IET Microwaves, Antennas & Propagation, ISSN 1751-8725, E-ISSN 1751-8733, Vol. 11, no 7, p. 1057-1063Article in journal (Refereed)
    Abstract [en]

    In this study, a design scheme for high-performance tight coupling microstrip coupler is proposed by adding a fragment-type compensated structure between two loosely coupled lines. Owing to its flexibility and adaptability, the fragment-type compensated structure can not only provide a quarter-wavelength phase shift for coupling enhancement, but also compensate the difference in the phase velocities of the even- and odd-modes for high directivity. Design of the fragment-type compensated structure can be implemented by multi-objective optimisation searching with several design objectives characterising tight coupling couplers. A high-efficiency optimisation searching strategy by using two-dimensional median filtering operator is employed to improve the efficiency of multi-objective optimisation. For demonstration, a high-performance 3-dB tight coupling directional coupler operating at 2 GHz is designed. The measurement data demonstrates a maximum directivity of 47 dB, above 25 dB directivity in a 21.5% bandwidth, a maximum variation of 0.3 dB in the coupling level and a maximum power division ratio of 0.6 dB, which indicate the overall performance better than the previously reported 3-dB couplers. In addition, a simplified theoretical analysis of the proposed coupler and full-wave simulated results are provided for better understanding of the fragment-type compensated structure.

  • 21558.
    Wang, Q.
    et al.
    Department of Electronics, Telecommunications Norwegian University of Science and Technology, Trondheim N-7491, Norway.
    Zhang, Tingting
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Balasingham, I.
    Department of Electronics, Telecommunications Norwegian University of Science and Technology, Trondheim N-7491, Norway.
    Characterizing the traffic load distribution in dense wireless sensor networks2011In: Journal of Networks, ISSN 1796-2056, E-ISSN 1796-2056, Vol. 6, no 2, p. 173-180Article in journal (Refereed)
    Abstract [en]

    Traffic load is typically not evenly distributed over the sensor nodes in a wireless sensor network (WSN). Understanding the traffic load distribution can guide the network-wide energy allocation, the design of routing algorithms, and the optimization of the node deployment in WSNs. This article considers a dense WSN with nodes uniformly distributed in a disk sensing area, where the expected traffic load distribution over the sensor nodes as a function of their distance from the sink has been derived. Further, the effects of the network scale and routing strategy on traffic load distribution are also investigated. The expected traffic loads beared by individual sensor nodes are found to be in direct proportion to the radius of the network and inversively proportional to the routing hop length but it is independent of the network density. In addition, a heuristic multipath routing algorithm is found to be capable of reducing the traffic load variance experienced by neighboring or symmetrically deployed sensor nodes. The results presented in this article are verified through extensive simulation experiments. © 2011 ACADEMY PUBLISHER.

  • 21559.
    Wang, Qinghua
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Malicious code detection in LRD networks2005In: Proceedings of the 3rd Regional Inter-University Postgraduate Electrical and Electronic Engineering Conference (RIUPEEEC'05), July 2005, Hongkong, China, 2005Conference paper (Other academic)
    Abstract [en]

    Following the development of Internet and the improvement of network services, network malicious code, delegated by worms, has become a major threat to peoples normal life. The research work related to worm detection is urgent but difficult. In this paper, we present a worm trend early detection method based on the long-range dependence (LRD) analysis of scan traffic entering the monitored network. Simulating experiments combined with real scan traffic show that our method can detect uniform scan worms at early stage. In addition, because our method is based on the idea of trend detection, not traditionally burst detection, generic hacker attacks and scans cannot cause false alarms for their stochastic essence.

  • 21560.
    Wang, Qinghua
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Traffic Analysis, Modeling and Their Applications in Energy-Constrained Wireless Sensor Networks: On Network Optimization and Anomaly Detection2010Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Wireless sensor network (WSN) has emerged as a promising technology thanks to the recent advances in electronics, networking, and information processing. A wide range of WSN applications have been proposed such as habitat monitoring, environmental observations and forecasting systems, health monitoring, etc. In these applications, many low power and inexpensive sensor nodes are deployed in a vast space to cooperate as a network.

    Although WSN is a promising technology, there is still a great deal of additional research required before it finally becomes a mature technology. This dissertation concentrates on three factors which are holding back the development of WSNs. Firstly, there is a lack of traffic analysis & modeling for WSNs. Secondly, network optimization for WSNs needs more investigation. Thirdly, the development of anomaly detection techniques for WSNs remains a seldomly touched area.

    In the field of traffic analysis & modeling for WSNs, this dissertation presents several ways of modeling different aspects relating to WSN traffic, including the modeling of sequence relations among arriving packets, the modeling of a data traffic arrival process for an event-driven WSN, and the modeling of a traffic load distribution for a symmetric dense WSN. These research results enrich the current understanding regarding the traffic dynamics within WSNs, and provide a basis for further work on network optimization and anomaly detection for WSNs.

    In the field of network optimization for WSNs, this dissertation presents network optimization models from which network performance bounds can be derived. This dissertation also investigates network performances constrained by the energy resources available in an indentified bottleneck zone. For a symmetric dense WSN, an optimal energy allocation scheme is proposed to minimize the energy waste due to the uneven energy drain among sensor nodes. By modeling the interrelationships among communication traffic, energy consumption and WSN performances, these presented results have efficiently integrated the knowledge on WSN traffic dynamics into the field of network optimization for WSNs.

    Finally, in the field of anomaly detection for WSNs, this dissertation uses two examples to demonstrate the feasibility and the ease of detecting sensor network anomalies through the analysis of network traffic. The presented results will serve as an inspiration for the research community to develop more secure and more fault-tolerant WSNs.

  • 21561.
    Wang, Qinghua
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Zhang, Tingting
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    A Multi-homing Extension of Wireless Node Implementation in Ns-22009In: 2009 4th International Conference on Communications and Networking in China, CHINACOM 2009: ChinaCom'09, IEEE conference proceedings, 2009, p. 751-756Conference paper (Refereed)
    Abstract [en]

    Due to the rapid growth of wireless communication, it is now believed that wireless devices with multiple interface support will highly increase in the near future. In the research community of Network Simulator, there has recently been quite a large interest in extending the current wireless node implementation so as to be able to include more than one radio interface to work simultaneously.

    We focus our efforts on the extension of multi-homing ability of ns-2, which has been the most used network simulator in wireless network research. Multi-homing here is defined as the ability of a single end-point to support multiple IP addresses by the use of multiple interfaces. The ns-2 simulation environment is a flexible tool for network engineers to investigate how various protocols perform with different configurations and topologies. However, the support for wireless and mobile networking in ns-2 is monolithic and not entirely consistent with basic design principles so that it makes it quite difficult, if not impossible, to extend a multi-homing support based on current mobilenode design. This paper describes how we extend the ns-2 framework to include support for an imititated wireless multi-homed node.

  • 21562.
    Wang, Qinghua
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Zhang, Tingting
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    A Survey on Security in Wireless Sensor Networks2009In: Security in RFID and Sensor Networks, Boca Raton: CRC Press, 2009, p. 293-320Chapter in book (Other academic)
    Abstract [en]

    Recent advances in electronics and wireless network technologies have offered us access to a new era where wireless sensor networks formed by inter-connected small intelligent sensing devices provide us the possibility to form smart environments. Considering the specialty of wireless sensor network, the security threats and possible countermeasures are quite different from those in Internet and Mobile Ad Hoc Networks (MANETs). On the one hand, the wireless communication, large scale and possibly human unattended deployment make attacks in wireless sensor networks relatively easier to perform. Furthermore, all features that make sensor nodes cheap and thus sensor network application affordable, such as limited energy resource, limited bandwidth and limited memory, also make many well-developed security mechanisms inappropriate in sensor networks. On the other hand, the user unfriendly interface makes the physical compromise of a sensor node difficult, the relatively simple communication profile makes the intrusion detection easy to perform, and also the redundant deployment makes the new type of network more fault-tolerant. Thus, we need a complete redesign of sensor network security mechanisms from technique to management.

  • 21563.
    Wang, Qinghua
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Zhang, Tingting
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Bottleneck Zone Analysis in Energy-Constrained Wireless Sensor Networks2009In: IEEE Communications Letters, ISSN 1089-7798, E-ISSN 1558-2558, Vol. 13, no 6, p. 423-425Article in journal (Refereed)
    Abstract [en]

    In a typical sensor network, nodes around the sink bear more energy consumption than those further away. It is not unusual that limited energy resources available at the nodes around the sink become the bottleneck which confines the whole network's performance. In this article, we firstly formally define the so-called bottleneck zone inside sensor networks. Then, the effect of the bottleneck zone on network performance is investigated by deducting performance bounds limited by the energy resources available inside the bottleneck zone. In this article, both the performance bound in terms of network lifetime and the performance bound in terms of information collection are explored. Finally, the ways by which network deployment parameters may affect the performance bounds are analyzed.

  • 21564.
    Wang, Qinghua
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Zhang, Tingting
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Characterizing the traffic load distribution in dense sensor networks2009In: 3rd International Conference on New Technologies, Mobility and Security, NTMS 2009, IEEE conference proceedings, 2009, p. 5384829-Conference paper (Refereed)
    Abstract [en]

    Traffic load is not evenly distributed over the nodes in a wireless sensor network (WSN). Understanding the traffic load distribution can guide the network-wide energy allocation, direct the design of routing algorithms, and optimize the node deployment in WSNs. In this paper, we consider a dense WSN with nodes uniformly distributed in a disk sensing area, and find the traffic load distribution over the nodes as a function of their distance from the sink. Further, the effects of network scale and routing strategy on traffic load are also investigated. The traffic loads on individual nodes are found to be in direct proportion to the radius of the network and in inverse proportion to the routing hop distance, while independent of network density. The results presented in this paper are verified through extensive simulation experiments.

  • 21565.
    Wang, Qinghua
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Zhang, Tingting
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Detecting anomaly node behavior in wireless sensor networks2007In: Proceedings - 21st International Conference on Advanced Information Networking and Applications Workshops/Symposia, AINAW'07, USA: IEEE conference proceedings, 2007, Vol. 2, p. 6p. 451-456, article id 4221100Conference paper (Refereed)
    Abstract [en]

    Wireless sensor networks are usually deployed in a way "once deployed, never changed". The actions of sensor nodes are either pre-scheduled inside chips or triggered to respond outside events in the predefined way. This relatively predictable working flow make it easy to build accurate node profiles and detect any violation of normal profiles. In this paper, traffic patterns observed are used to model node behavior in wireless sensor networks. Firstly, selected traffic related features are used to translate observed packets into different events. Following this, unique patterns based on the arriving order of different packet events are extracted to form the normal profile for each sensor node during the profile learning stage. Finally, real time anomaly detection can be achieved based on the profile matching.

  • 21566.
    Wang, Qinghua
    et al.
    Department of Electronics and Telecommunications, Norwegian University of Science and Technology (NTNU), NO-7491 Trondheim, Norway.
    Zhang, Tingting
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Fair energy allocation in large-scale and dense sensor networks2010In: GLOBECOM - IEEE Global Telecommunications Conference, IEEE conference proceedings, 2010, article id 5683414Conference paper (Refereed)
    Abstract [en]

    This paper deals with the energy allocation in multi-hop wireless sensor networks. Because the traffic loads are not evenly distributed in a multi-hop wireless sensor network, different sensor nodes usually experience different energy consumption rates. We present Routing Independent Fair Energy-Allocation Scheme (RIFES), which allocates the available energy resource to a sensor node according to its pre-estimated traffic load. Because traffic load is the dominating source of energy consumption, RIFES optimizes the network's lifetime by equalizing all individual nodes' expected energy exhaustion times. Due to the fact that a node's real experienced traffic load may differ to its pre-estimated traffic load in practice, it is hard for RIFES to achieve its theoretical optimal performance. To bridge this gap between theory and practice, this paper also presents several distributed routing algorithms, the use of which prolongs the network's lifetime by balancing the real-experienced traffic loads among neighboring nodes

  • 21567.
    Wang, Qinghua
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Zhang, Tingting
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Sec-SNMP: Policy-Based Security Management for Sensor Networks2008In: SECRYPT 2008: PROCEEDINGS OF THE INTERNATIONAL CONFERENCE ON SECURITY AND CRYPTOGRAPHY, Portugal: INSTICC Press, 2008, p. 222-226Conference paper (Refereed)
    Abstract [en]

    In this paper, we present a sensor network security management framework called Sec-SNMP, which organizes and manages security related behaviors in sensor networks based on security policies. There are three main components in Sec-SNMP: Sec-SNMP manager, Sec-SNMP agent and a policy control and deployment protocol. Sec-SNMP manager provides the interface between human administrator and the managed mesh network. Sec-SNMP agent represents Sec-SNMP manager to enforce security policies within the managed mesh network. The policy control and deployment protocol allows the communication between Sec-SNMP manager and Sec-SNMP agents. The security management for sensor networks is still in its germinal stage, and this paper provides a good guideline for future research.

  • 21568.
    Wang, Qinghua
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Zhang, Tingting
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Simulated Wireless Multihomed Node in NS-22009In: The Sixth Swedish National Computer Networking Workshop and Ninth Scandinavian Workshop on Wireless Adhoc Networks, 2009Conference paper (Refereed)
    Abstract [en]

    Due to the rapid growth of wireless communication, it is now believed that wireless devices with multiple interface support will highly increase in the near future. In the research community of Network Simulator, there has recently been quite a large interest in extending the current wireless node implementation so as to be able to include more than one radio interface to work simultaneously. We focus our efforts on the extension of multihoming ability of ns-2, which has been the most used network simulator in wireless network research. Multihoming here is defined as the ability of a single end-point to support multiple IP addresses by the use of multiple interfaces. The ns-2 simulation environment is a flexible tool for network engineers to investigate how various protocols perform with different configurations and topologies. However, the support for wireless and mobile networking in ns-2 is monolithic and not entirely consistent with basic design principles so that it makes it quite difficult, if not impossible, to extend a multihoming support based on current mobilenode design. This paper describes how we extend the ns-2 framework to include support for an imititated wireless multihomed node.

  • 21569.
    Wang, Qinghua
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Zhang, Tingting
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Source Traffic Modeling in Wireless Sensor Networks for Target Tracking2008In: The 5th ACM International Symposium on Performance Evaluation of Wireless Ad-Hoc, Sensor, and Ubiquitous Networks (PE-WASUN'08), USA: Association for Computing Machinery (ACM), 2008, p. 96-100Conference paper (Refereed)
    Abstract [en]

    Researches around wireless sensor network (WSN) were very prolific recently. However, traffic modeling related WSN research was poorly less. In this paper, source traffic dynamics in a simulated target tracking WSN scenario are explored. We find the source traffic arrival process doesn't follow the usually considered Poisson model. Instead, an ON/OFF model is found to be capable of capturing the burst nature of source traffic arrival. Further, we find the measured ON/OFF periods follow the generalized Pareto distribution perfectly. Mathematical analysis also shows a surprising fact: all ON/OFF period distributions in the experiment exhibit short-tail property, which is a nice property that could be exploited by applications such as anomaly detection and node failure detection.

  • 21570.
    Wang, Qinghua
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Zhang, Tingting
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Traffic load analysis in large-scale and dense wireless sensor networks2009In: The Sixth Swedish National Computer Networking Workshop and Ninth Scandinavian Workshop on Wireless Adhoc Networks, 2009Conference paper (Refereed)
    Abstract [en]

    Traffic load is not evenly distributed over the nodes in a multi-hop wireless sensor network (WSN). Understanding the traffic load distribution can guide the network-wide energy allocation, direct the design of routing algorithms, and optimize the node deployment in WSNs. In this paper, we find the traffic load distribution over the nodes as a function of their respective distance from the sink. Further, the ratio of the traffic loads experienced by two nodes at different locations is found to be independent of the underlying routing algorithm. The assumptions in this paper are that the network is large-scale and dense, and it is deployed in a disc area. However, the results achieved could also be used as approximations in more practical networks.

  • 21571.
    Wang, Qinghua
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Zhang, Tingting
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Traffic load distribution in large-scale and dense wireless sensor networks2010In: 2010 The 5th Annual ICST Wireless Internet Conference, WICON 2010, 2010, p. No 5452655-Conference paper (Refereed)
    Abstract [en]

    Because of the dominating many-to-one communication pattern, traffic load is not evenly distributed over the nodes in a wireless sensor network (WSN). In a large-scale WSN, the multi-hop routing even deteriorates this traffic load imbalance by accumulating traffic flows along their paths to the sink. Understanding the traffic load distribution can guide the network-wide energy allocation, direct the design of routing algorithms, and optimize the node deployment in WSNs. In this paper, we consider a large-scale and dense WSN with nodes evenly deployed in a disk area, and find the traffic load distribution over the nodes as a function of their distances from the sink. Further, the effects of network scale and routing hop length on traffic load distribution are also investigated. The traffic loads of individual nodes are found to be in direct proportion to the radius of the network and in inverse proportion to the mean routing hop length, while independent of network density. The results presented in this paper are verified through extensive simulation experiments.

     

     

  • 21572.
    Wang, Qinghua
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Zhang, Tingting
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Pettersson, Stefan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    An effort to understand the optimal routing performance in wireless sensor network2008In: Proceedings of the 22nd International Conference on Advanced Information Networking and Applications: AINA2008, Ginowan City , Okinawa, Japan. 25-28 March 2008, IEEE conference proceedings, 2008, p. 279-286Conference paper (Refereed)
    Abstract [en]

    Wireless sensor network is remarkable for its promising use on human-unattended information collection, such as forest fire monitoring. In order to support efficient communication, many routing algorithms specially designed for such networks have been proposed. However, there is no idea about whether these proposed routing algorithms are already good enough or still have a long way to become “perfect”, since there is currently a lack of understanding about the optimal routing performance. This paper makes a progress in the understanding of the optimal routing performance. Metrics here used to measure the routing performance are the network lifetime finally acquired and the total information finally collected. The condition used to judge the network’s death is defined by the user’s requirement on the guaranteed network information collecting ability. Optimization models based on the metrics and death condition mentioned above are proposed. Experiments show some existing routing proposals already work well when the user’s requirement is strict, but few of them satisfy when the user’s requirement is loose.

  • 21573.
    Wang, Qinghua
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Zhang, Tingting
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Pettersson, Stefan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Bounding the Information Collection performance of Wireless Sensor Network Routing2007In: CNSR 2007: Proceedings of the Fifth Annual Conference on Communication Networks and Services Research, Washing, DC. USA: IEEE conference proceedings, 2007, p. 55-62Conference paper (Refereed)
    Abstract [en]

    Wireless sensor networks have maily been designed for information-collecting purposes, such as habitat monitoring, product process tracing, battlefield surveillance, etc. In order to support efficient communications for such networks, many routing protocols have been proposed. However, protocol designs are out-pacing formal analysis. We propose an optimization model in this paper to bound the routing performance in terms of network information collection. We first argue that a network can only be given a death sentence when it fails to satisfy the application's requirement and propose a more reasonable network lifetime definition. Then, the optimization model concerning maximizing information collection routing is presented based on this new network lifetime definition. Existing typical routing algorithms: MH, MTE, FA and MREP are simulated as references to validate the model proposed. Results show our model can provide a tight upper bound and thus can be used to evaluate existing and up-coming routing algorithms.

  • 21574.
    Wang, Simiao
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Research on new approach for NAT traversal: ID-Traversal2012Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
  • 21575.
    Wang, Xiasong
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Rödjegård, H
    Oelmann, Bengt
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Martin, H
    Larsson, B
    High performance CO2 measurement based on pressure modulation2010In: Proceedings of 24th Eurosensors Conference, Elsevier, 2010, p. 1208-1211Conference paper (Refereed)
    Abstract [en]

    Herein pressure modulation is proposed as a method to increase the resolution as well as to eliminate long term drift of NDIR gas sensors. Measurements are presented that verifies the theoretical predictions of possibility to drift compensation and resolution improvement. The resolution is increased 8.6 times when the pressure is changed from atmospheric to 900 kPa. The method can be applied to existing sensors for both resolution improvement and drift compensation.

  • 21576.
    Wang, Xu
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Investigation of methods for determination of Wireless Node's Cluster Connectivity2015Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Recent advancement in wireless communications and electronics has enabled the development of sensor networks. With development in technology, wireless sensor network is used more and more in our daily life, because the technology is more flexible and cheaper than the wired sensor network. The objective of this study has been to solve the problem that how closely a group of mobile wireless nodes are clustered. Matlab is used to simulate the various situations of nodes. There are two major parts in this software design. One is the function of detecting the movement of the mouse. Another is the function of estimating the connectivity of the nodes. Some methods will be proposed and evaluated through some realistic scenarios.

  • 21577.
    Wang, Xu
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Object Classification with Thermal-Visual Images2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Image classification is an image processing technique used to separate different categories in a dataset according to unique image information. It has many fields of application, such as medicine, security monitoring, component defect detection, people counting, license plate recognition and robot positioning. There are many challenges in the field of image classification. For example, poor image quality leads to poor results. Moreover, there is need to study how to improve the recognition rate, reduce the amount of calculation and strengthen the robustness [1].

    Classification algorithms are tested for visual images in outdoor environments. However, vision sensors are sensitive to light. When there is no light, the signal to noise ratio in the visual images will be poor. This in turn could lead to false classification. To circumvent this problem, a sensor of another spectral band can be used, making sensing independent of lighting conditions. An example of this is thermal images which can be created by sensing the infrared radiation from objects. To evaluate the classification accuracy of different algorithms based on different image types, we developed five datasets: thermal raw images, visual raw images, thermal binary images, visual binary images and fused images. In this study, each dataset includes two different objects, a human and a bicycle. The classification algorithms used for investigations include HOG, SIFT and SURF. The first high level analysis is performed on a personal computer (PC). After analysis, SIFT and SURF algorithms were implemented on an embedded platform, NVIDIA TEGRA TK1.

    The results show that thermal raw images is better for object classification compared to visual raw, thermal binary, visual binary and fused thermal-visual images. Regarding classification algorithms, the SIFT algorithm performs better with 93.3% accuracy compared to HOG and SURF which have 86.4% and 91.7% respectively.

  • 21578.
    Wang, Y.
    et al.
    School of Electronics and Information Engineering, Beijing Jiaotong University, Beijing, China .
    Barac, Filip
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information and Communication systems.
    Implementation of the WirelessHART MAC layer in the OPNET simulator2013In: Proceedings of 2013 3rd International Conference on Computer Science and Network Technology, ICCSNT 2013, IEEE conference proceedings, 2013, p. 663-668Conference paper (Refereed)
    Abstract [en]

    WirelessHART standard is the first international standard for Industrial Wireless Sensor Networks (IWSN) approved by International Electrotechnical Commission (IEC), and, as such, it is worthwhile to implement on simulator platforms. Based on the study of WirelessHART standard, this paper is a primary implementation of the Medium Access Control layer of WirelessHART standard. To our best knowledge, this is the first comprehensive implementation of WirelessHART using the OPNET simulator. This paper also proposes the improvement of shared slot access method by using slotted Carrier Sense Multiple Access/Collision Avoidance (CSMA/CA), which outperforms the existing slotted ALOHA by increasing the throughput for 2% and reducing the packet loss. Flexible dedicated slot assignment has also been proposed to reduce the packet loss rate caused by influences of the physical channel.

  • 21579.
    Wang, Ying
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Engineering and Sustainable Development.
    Potential Nano-Ecotoxicity of Zinc Oxide Nanoparticles Through Its Influence to Fungi2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Nanotechnology is a fast growing scientific area, and the related industries have rising in the air. Nanomaterials that involved in the nanotechnology are rather small and with unique properties that we have not yet fully understood. In this point of view, we need to gain more knowledge about the influence of nanomaterials to the natural ecology, since we will soon face a lot of “Nano wastes”. The objective of this study is to understanding the influence of ZnO nanoparticles to different fungi, and how it changes their growing competence. Through the results, we can analyze the potential eco-toxicity of the ZnO nanoparticles, which is considered as safe materials when it in the size scale of micrometers or bigger. We selected four fungi and observed their growth under six different ZnO nanoparticle concentrations, and found that the nanoparticles have different effect on the growth of different fungi. Also, we found ZnO nanoparticles can change the balance of two fungi that were growing at the same culture. Based on the results, we discussed three models about how the nanoparticles could be toxic to the forest eco-system, and conclude that there are potential risks if the nanoparticles are explored to the nature. 

  • 21580.
    Wang, Yun
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Jiang, Wenxuan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Statistical Processing of IEEE 802.15.4 Data Collected in Industrial Environment2013Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Wireless sensor network, which is constitute of autonomous sensors, is used for monitoring physical or environmental conditions like temperature, sound, pressure, and so on. The dispersed sensors or nodes will respectively pass their data through the network to the main location. Currently, several standards are ratified or in developing for wireless sensor network, like Wireless Hart, ISA, 100.11a, WIA-PAA, IEEE 802.15.4, etc. Among the standards, Zigbee is often used in industrial applications that require short-range and low-rate wireless transfer. In the research, all the data is collected under industrial environment using IEEE 802.15.4 compliant physical layer, some packets are interfered only by multi-path fading while others are also interfered by Wi-Fi interference. The goal of the thesis is to find out the dependence between the received power (RSS), correlation value (CORR) and bit error rate (BER) of the received message, and their distribution in situations both when the packet is lost or not. Besides, the performance of bit error rate such as the distribution and the features of burst error length under Wi-Fi interference or not will also be tested. All of them are based on a precise statistical processing. 

  • 21581. Wangler, A
    et al.
    Ekenberg, Love
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Johannesson, P
    Bridging High-Level Enterprise Models to Implementation-Oriented Models: Proceedings of SoMet2003Conference paper (Other scientific)
  • 21582.
    Wanqvist, Andrea
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Science Education and Mathematics.
    Begrep(p) du det där?: En studie om matematiska begreppssvårigheter i årskurs 52016Independent thesis Advanced level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    ”Det är med språket som instrument man synliggör matematiken ” Löwing (2011: 33).

    Denna studie redogör genom en undersökning, hur det matematiska språket och de matematiska begreppen är utvecklade och förankrade i elevernas diskurs i klassrummet under lektionstid samt om och hur läraren planerar för att underlätta begreppsinlärningen för eleverna mellan lektionspassen. Genom en komparativ och kvalitativ fältstudie där observationer och inspelat material som analyserats med hjälp av CA-metoden, utgör det empiriska materialet, besvaras följande frågor:

     Vilka matematiska begreppssvårigheter stöter eleverna på och vad beror det på?

     Hamnar eleverna i en diskurs utanför problemet och vad kan det bero på?

     Hur arbetar läraren förebyggande för att inte svårigheter i text och diskurs ska uppkomma?

     Hur korrigerar och underlättar läraren sin undervisning för att undvika matematiska svårigheter för eleverna?

     

    Resultatet visar att eleverna ej har en tillräcklig utvecklad och eller förankrad begreppskunskap. Detta beror till viss del på lärarens otillräckliga genomgång av de matematiska begreppens innebörd. Eleverna hamnar ofta i diskurser utanför ämnet, vilket kan härledas till bland annat för avancerade uppgifter. Läraren arbetar inte i enlighet med sin egen utsaga om hur denna skulle förebygga svårigheter för eleverna eller korrigera sina lektioner för att undvika de matematiska svårigheter som uppkommer.

  • 21583.
    Wanqvist, Andrea
    Mid Sweden University, Faculty of Human Sciences, Department of Humanities.
    Får jag svära?: En undersökning om svordomsanvändning i en grundskoleklass2016Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
  • 21584.
    Wantke, K-D
    et al.
    Max-Planck-Institute.
    Fruhner, H.
    Max-Planck-Institute.
    Örtegren, Jonas
    Max-Planck-Institute.
    Surface dilational properties of mixed sodium dodecyl sulfate/dodecanol solutions2003In: Colloids and Surfaces A: Physicochemical and Engineering Aspects, ISSN 0927-7757, E-ISSN 1873-4359, Vol. 221, no 1-3, p. 185-195Article in journal (Refereed)
    Abstract [en]

    The surface dilatational properties of aqueous solutions of sodium dodecyl sulfate (SDS) and n-dodecanol areinvestigated in the frequency range 15/f5/500 Hz using the oscillating bubble method. The results demonstrate that apure dodecanol solution has an elastic surface without viscous effect whereas the surface of a SDS solution withoutadded dodecanol exhibits a strong viscoelastic behavior. Mixtures show graduated properties. The time behavior oftheir surface dilatational moduli demonstrates that dodecanol molecules drive the SDS molecules slowly out of thesurface. Therefore, the known one-component model describing the surface dilatational modulus can be used also forthese mixtures. A simple theoretical consideration explains this effect.

  • 21585.
    Warne, Brita
    Mid Sweden University, Faculty of Human Sciences, Department of Psychology.
    Drag av autism och annorlunda sensoriska upplevelser – finns samband medsjälvupplevd stress?2013Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
  • 21586.
    Warne, Maria
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Där eleverna är: Ett arenaperspektiv på skolan som en stödjande miljö för hälsa2013Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Health is not created in a vacuum but in the relationship between individuals and their surroundings. School is therefore an important arena for children and youth since they spend the majority of their waking hours there. Earlier research has been particularly focused on risk factors related to mental illness in children and youth, rather than what promotes and strengthens their possibilities for positive health. Through a salutogenic approach, one can obtain knowledge about factors that contribute to a supportive environment for health. In order to gain understanding of the needs and values of new generations, students need to be made a part of their studies and the development of their own everyday environment.

    The aim of the dissertation was to study school as a supportive environment for health by involving students and finding methods of studying the positive aspects of health. The aim of the articles included challenges and possibilities for using a method to increase participation, deepen the understanding about aspects that promote health and learning, with a special focus on participation and support and how positive health can be measured.

    Students in a high school were chosen to be the participants in two qualitative studies. The method of photovoice was studied through sound recordings of the students’ dialogue during their work with photovoice and their points of view as well as the teachers’ during the focus group interviews. Data was analyzed by using content analysis (Paper I). Grounded theory was used to study the students’ view of what is important to health and learning (Paper II). A survey was used to create a positive health scale and to study factors associated with health among students in grades 6-9. The survey was taken by 1527 students (52,3% girls, 47,7% boys) in grades 6-9 in schools in the municipality of Östersund. The response rate was 80%. A principal component analysis was used to adjust and validate a positive health scale for the age group 12-16 (Paper III). In order to study the association between factors that might be associated with positive health, a multiple logistic regression was chosen (Paper IV).

    The results showed that photovoice worked as a method in high school to increase participation in matters related to health and learning. However the method needed to be adjusted to the student group. Photovoice was perceived as stimulating but also challenging by both teachers and students. Critical aspects were tied to the teacher role and the democratic organization (Paper I). The students’ view of what promoted health and learning were related to treatment, personal and pedagogical support and the potential for recovery. The results also showed that students regarded school as something that creates distinction between those who perceived themselves as under or over achievers (Paper II). The positive health scale (PHS) proved to be valid for students 12-16 years old and the scale should be useful for work with systematic health promotion where the starting point is a salutogenic perspective (Paper III). Factors associated with positive health among girls and boys age 12-16 were: a perceived participation in the classroom, support from teachers and friends and support from both parents. Socioeconomic status, measured as having as much money as pupils, was shown to be independently associated with positive health (Paper IV).

    The conclusion was that important factors for a supportive environment for health were; students’ perception of and possibility to participate in the classroom and in the school’s work environment, personal support from teachers and support in their education, support from friends and conditions that permit recovery during and after school. At the same time the results showed that there are distinctions between different groups of students in relation to health and support.

    In order to develop a supportive environment for health in schools, photovoice can be used to engage students and discover unique aspects of the individual school. With the help of the positive health scale (PHS), promoting factors can be examined, which increases the possibilities for systematic health promoting work with a salutogenic perspective.

  • 21587.
    Warne, Maria
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Med våra ögon: en metodbok om photovoice2012Book (Other academic)
  • 21588.
    Warne, Maria
    et al.
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Danielsson, Erna
    Mid Sweden University, Faculty of Human Sciences, Department of Social Sciences.
    Högberg, Lovisa
    Mid Sweden University, Faculty of Human Sciences, Department of Business, Economics and Law.
    Torget: en plats för hållbarhet ur ett socialt, ekologiskt, kulturellt och ekonomiskt perspektiv2017In: Hållbarhetens många ansikten: samtal, forskning och fantasier / [ed] Edith Andresen, Gustav Lidén, Sara Nyhlén, Sundsvall: Mid Sweden University , 2017, p. 64-71Chapter in book (Other academic)
  • 21589.
    Warne, Maria
    et al.
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Gillander Gådin, Katja
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Snyder, Kristen
    Mid Sweden University, Faculty of Human Sciences, Department of Education.
    Photovoice: An opportunity and challenge for students' genuine participation2013In: Health Promotion International, ISSN 0957-4824, E-ISSN 1460-2245, Vol. 28, no 3, p. 299-310Article in journal (Refereed)
    Abstract [en]

    It has been highlighted that youth empowerment and participationare important principles for school health promotion.Despite this fact, children and youth are rarelygiven instruments to participate or to influence their situationsand the environments in their schools. Photovoice isa method to increased empowerment and participation.Originally it was created as a community action researchmethod based on Freire’s critical pedagogy and feministtheory. The purpose of this study was to explore challengesand opportunities for applying photovoice in aschool setting to support genuine participation. Togetherwith teachers and students in an upper secondary schoolin O ¨ stersund’s municipality in the north of Sweden, thephotovoice method was field tested and modified to aclassroom situation. The teachers and the students wereinterviewed about their experiences with the method. Theresults were interpreted by content analysis and showedthat the teachers’ capability to be facilitators and the students’possibility to make a difference for the school orthe municipality were the most important factors tosucceed with photovoice. The conclusions were thatphotovoice challenges schools and society to have a betterstructure for genuine participation if youth participation isseen as valuable.

  • 21590.
    Warne, Maria
    et al.
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Siandinovic, Kristina
    Karolinska Institutet.
    Berman, Anne H
    Karolinska Institutet.
    Källmén, Håkan
    STAD, Centre for Psychiatry Research, Stockholm.
    Vinberg, Stig
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Risky consumption of alcohol and drugs among employees at ski resorts2017In: Nordic Studies on Alcohol and Drugs, ISSN 1455-0725, E-ISSN 1458-6126, Vol. 34, no 3, p. 201-216Article in journal (Refereed)
    Abstract [en]

    Aim: To evaluate risky consumption of alcohol and drugs among Swedish men and women who are employed at ski resorts. Methods: A cross-sectional sample of 611 employees in 48 small and medium-sized enterprises responded to a questionnaire covering alcohol and drug use, social aspects around work and working conditions. Consumption of alcohol and drugs in the study sample was compared to population data. Data were analysed using Mann–Whitney U-tests and logistic regression analyses. Results: Compared to the general population, the study group of ski resort employees had higher scores on the Alcohol Use Disorders Identification Test (AUDIT) in all age groups except 35+ for men. Regarding the Drug Use Disorders Identification Test (DUDIT) scores, only men in the 18–24 age group had higher scores compared to the general population. The prevalence of risky alcohol and drug use was higher among seasonally employed individuals; 82.9%, compared to 58.0% among other employees for alcohol; 8.3% compared to 2.8% for drugs. The regression analysis indicated that social aspects such as living together with colleagues and having co-workers/friends who are frequently inebriated were the most significant explanatory variables for explaining risk consumption of alcohol (OR 16.82 and OR 4.33). Risky use of drugs was associated with being younger (OR 0.15) and male (OR 0.86), as well as with having co-workers/friends who are frequently inebriated (OR 4.25). Conclusions: The study showed a high prevalence of risky alcohol consumption among ski resort employees compared to the general population, with higher risky drug consumption found only among younger men. Social aspects such as living with colleagues and having co-workers or friends who are often inebriated, were identified as important explanatory factors. Preventive measures should be introduced, targeting norms and work culture surrounding alcohol and drug use among ski resort employees. 

  • 21591.
    Warne, Maria
    et al.
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Snyder, Kristen
    Mid Sweden University, Faculty of Human Sciences, Department of Education.
    Gillander Gådin, Katja
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Adaptation and validation of a positive health scale for adolescents2014In: Social Indicators Research, ISSN 0303-8300, E-ISSN 1573-0921, Vol. 119, no 2, p. 1079-1093Article in journal (Refereed)
    Abstract [en]

    There is a demonstrated need to develop alternative approaches to measuring health from a positive health perspective in order to support systematic planning and evaluation of health promotion in schools. The Salutogenic Health Indicator Scale (SHIS) aims to measure health from a positive perspective, However, it has not been developed, or previously been tested, for use with adolescents between the ages of 12 and 16, at which age youth often exhibit a need for extra support in order to be successful in school and life. Inspired by the SHIS, we generated a Positive Health Scale (PHS) appropriate for 12-16-year-olds and determined its validity and reliability using principal component analysis (PCA). In the study, the scale was tested in a sample of 1,527 Grade 6-9 students, using PCA. The findings indicated the need to reduce the scale to nine items, which was then shown to be valid and reliable for use with both adolescent boys and adolescent girls. We conclude that the PHS can be used in systematic health promotion planning and evaluation. Communities and schools can use this scale to examine and improve health determinants in different adolescent settings.

  • 21592.
    Warne, Maria
    et al.
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Snyder, Kristen
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Gillander Gådin, Katja
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Participation and support – associations with Swedish pupils’ positive health2017In: International Journal of Circumpolar Health, ISSN 1239-9736, E-ISSN 2242-3982, Vol. 76, no 1, article id 1373579Article in journal (Refereed)
    Abstract [en]

    From the perspective of salutogenesis, schools have opportunities to create supportive environments for health and well-being, but there is a need for more knowledge about positive health determinants in the school setting. The aim of this study was to analyse adolescents’ self-reported positive health and its association with supportive factors in the school environment. Data was derived from a cross-sectional study in which pupils were aged 12–16 (n=1527). A positive health scale was used to examine the association of positive health with the following determinants: classroom participation; teacher support; peer support; parental support; and personal relative affluence. Data was analysed with multiple logistic regression. The results showed that positive health was associated with classroom participation and support from teachers and parents more commonly among boys than girls. All determinants were significantly associated with pupils’ positive health. The conclusion is that students’ positive health is strongly associated with support from the school. Classroom participation and support are major concerns for the health of pupils, and it is essential to develop these aspects of the school environment.

  • 21593.
    Warne, Maria
    et al.
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Snyder, Kristen
    Mid Sweden University, Faculty of Human Sciences, Department of Education.
    Gillander Gådin, Katja
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Promoting an Equal and Healthy Environment: Swedish Students' View of the Daily Life at School2013In: Qualitative Health Research, ISSN 1049-7323, E-ISSN 1552-7557, Vol. 23, no 10, p. 1354-1368Article in journal (Refereed)
    Abstract [en]

    Education is an important factor in health equity, but many students still do not complete high school. A focus on the school context rather than on individual problems might help to create a supportive environment for health and learning. In this study we explored factors that promote health and learning from the perspective of vocational and low-achieving high school students in Sweden. We used grounded theory with a constructivist orientation, informed and sensitized by the concept of salutogenesis. Students from a school in a mid-sized municipality in Sweden participated, and we collected data using the photovoice method and interviews. Students identified general factors as significant to their well-being and success in school. The main theme, "promoting driving forces for health and learning," emerged from the categories "longing to be seen by teachers," "longing for support," and "longing for recuperation."

  • 21594.
    Warne, Maria
    et al.
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Snyder, Kristen
    Mid Sweden University, Faculty of Human Sciences, Department of Education.
    Gillander Gådin, Katja
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    The role of participation, teachers and peers in grades 6–9: A cross-sectional questionnaire study of factors associated with pupils’ positive health in Swedish schoolsManuscript (preprint) (Other academic)
    Abstract [en]

    The influence of the school environment on pupils’ health has more often been described in terms of health problems than health. From a perspective of health promotion and salutogenesis, schools have opportunities to create supportive environments for health. From this point of departure there is a need for more knowledge about positive health determinants in the school setting. The aim of this study was to analyze adolescents’ self-reported positive health and its association with supportive factors in the school environment. Data were derived from a cross-sectional study in which pupils aged 12–16 completed a questionnaire during school hours (n= 1527). The response rate was 80%). A new positive health scale was used to examine the association with the following determinants: classroom participation, school-related support, peer support, parent support and socioeconomic status. Data were analyzed with chi-squared tests and multiple logistic regression. The results showed that positive health, participation and support from teachers and parents were more common among boys than girls. All determinants except support with homework from the school were significantly associated with pupils’ positive health. The conclusion is that schools have a great potential to enable pupils’ health. The association between support from teachers and peers and participation is a major concern for pupils’ health and it is essential develop these aspects in the school environment.

  • 21595.
    Warne, Maria
    et al.
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Vinberg, Stig
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Alkohol och droger bland säsongsanställda på turistorter.: Medarbetares svar på frågor om alkohol, droger, anställningsvillkor, förebyggande arbete och hälsa2015Report (Other academic)
    Abstract [sv]

    En enkätstudie om riskkonsumtionen av alkohol och droger bland anställda i olika företag i Åre genomfördes våren 2014 av Avdelningen för Hälsovetenskap, Mittuniversitetet. Denna delrapport är framtagen till styrgruppen för projektet ”Trygg i Åre - arbetsgivare mot droger”. Projektet finansieras av Folkhälsomyndigheten och beräknas pågå under 2014-2016.

     

    Enkäten besvarades av 611 personer vilket motsvarar en svarsfrekvens på cirka 47 procent. Riskkonsumtion av alkohol mättes genom frågeformuläret AUDIT (Alcohol Use Disorders Identification Test). Gränsvärde för riskkonsumtion är 8 eller däröver för män och 6 eller däröver för kvinnor på en skala mellan 0-40. Drogbruk mättes genom DUDIT (Drog Use Disorders Identification Test). Gränsvärde för drogbruk för båda könen är 1 eller däröver.

     

    Resultatet visade att i gruppen 18-24 år fanns den högsta riskkonsumtionen av både alkohol och droger. I åldersgruppen 18-24 år fanns inga skillnader mellan könen när det gällde riskbruk av alkohol medan fler män än kvinnor visade sig ha ett drogbruk. När det gäller alkoholkonsumtionen i åldersgrupperna över 34 år är mönstret att männen i nästan dubbelt så hög grad har en riskkonsumtion i jämförelse med kvinnorna. Droganvändning förekom i stort sett inte bland dem som besvarat enkäten och var över 34 år.  

     

    Riskkonsumtionen av alkohol bland män och kvinnor visade sig vara associerat till:

     

    • Bo med kollegor/vänner
    • Ej vara fast boende i Åre
    • Ha vänner som dricker sig berusade ofta
    • Arbeta i högt tempo (endast män)
    • Om företaget inte använder slumpvisa utandningstester (endast män)

    Analysen av data visade ingen association mellan de undersökta faktorerna (boende, vänner som ofta dricker sig berusade, anställningsvillkor, riskkonsumtion av alkohol) och kvinnors bruk av droger. För männens del var bruk av droger associerat till:

     

    • Ha vänner som ofta dricker sig berusade
    • Bo med kollegor/vänner
    • Vara tillfälligt anställd
    • Ha en riskkonsumtion av alkohol

    Deltagarna i studien hade möjlighet att lämna förslag på vad de ansåg att arbetsgivaren skulle kunna göra ytterligare när det gällde det alkohol- och drogförebyggande arbetet. Fem områden identifierades:

     

    • Mer kontroller
    • Mer utbildning till anställda
    • Ett förändrat förhållningssätt till alkohol
    • Bättre hjälpinsatser om problem uppdagas
    • Det är bra som det är

    Enkäten innehöll även frågor om hälsa. Resultatet visade att en stor andel av de som svarat mår bra, mätt genom en positiv hälsoskala. Cirka 60 procent rör sig ordentligt en gång i veckan eller oftare. Merparten anser sig ha en meningsfull fritid.

     

    Den insamlade enkäten innehöll fler frågor och ytterligare analyser kommer att genomföras under projekttiden.

  • 21596.
    Warne, Maria
    et al.
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Vinberg, Stig
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Elefanten i rummet – ett interventionsprojekt med utmaningar2017Conference paper (Refereed)
    Abstract [sv]

    Baggrund (kontekst, problembeskrivelse, problemstilling og formål)Alkohol och droger bland säsongsanställda på skidturistorter är ett problem som beskrivits i ringa omfattning. Studier visar att förekomsten av alkohol och droger är högre i denna grupp än i befolkningen generellt. Många säsongsanställda är unga och i dessa år är risken stor att en riskfylld konsumtion av alkohol och droger leder till hälsoproblem i framtiden. Arbetsgivare och företrädare för kommun och landsting uppmärksammade problemet och erhöll finansiering av Folkhälsomyndigheten 2014-2016 för att genomföra en intervention i syfte att minska alkohol och droger bland säsongsanställda. Till projektet knöts forskare på ett universitet som genom följeforskning skulle följa och utvärdera projektet. 

    Teoretisk ramme og metodeMed utgångspunkt i systemteoretiskt perspektiv, observationer och samtal under en intervention om alkohol och droger bland anställda, diskuteras aspekter av problemägande, makt, kommunikation och samarbete mellan forskare och projektägare. Vilka hinder och möjligheter finns för sammabete mellan forskning och praktik när en intervention genomförs inom ett område som också är en del av projektägarnas näringsverksamhet? 

    Hovedresultater og konklusionerProjektets olika aktörer har olika bakomliggande syften vilka ställs på sin spets när projektresultat kommuniceras externt. Forskningens akademiska frihet, att vara oberoende gentemot marknaden, kan skapa konflikt med andra aktörer som har ett ekonomiskt intresse vilket kan äventyras av att resultat publiceras. Tät kontakt mellan universitet och praktik kan till viss del minska konflikten men metoder behöver utvecklas för att i ett tidigt skede tydliggöra roller, ansvarsområden samt forskarnas akademiska frihet. 

    Betydning for videre forskning, policy eller praksisI allt större utsträckning sker en samverkan mellan forskning och praktik och universiteten får uppdrag från det omgivande samhället. Fördelen är att forskningen når ut snabbare i samhället och kan komma till användning men det behövs fler studier som visar de problem som detta samarbete också kan leda till.

  • 21597.
    Warne, Maria
    et al.
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Vinberg, Stig
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Sun, snow, skiing, work and a lot of party – HR leaders and seasonal workers’ views on alcohol and alcohol prevention at a ski resort in Northern Sweden.2016In: Inkluderande och hållbart arbetsliv: Book of abstracts – FALF 2016, Östersund: Mittuniversitetet , 2016, p. 13-14Conference paper (Refereed)
    Abstract [en]

    Winter tourism hires thousands of young seasonal workers every year. Work, but mostly skiing and party attracts them to stay at the ski resort for four or five months.  Previous research shows that seasonal employment is associated with hazardous drinking and risk taking behaviors. Seasonal workers’ health and healthy working environment are important issues for the tourism sector. Between 2014 and 2016 the project “Safe in Åre – employer against drugs” is running with the purpose to reduce alcohol and drugs among seasonal employees.  

    A qualitative method was used to understand critical factors for alcohol prevention among seasonal workers. Twelve HR managers in tourism companies were interviewed about alcohol prevention and the role of alcohol in seasonal workers’ daily lives. The interviews were analyzed with content analysis together with one open ended questions about seasonal workers view of the companies’ alcohol- and drug prevention. The question was answered by 611 of 1313 employees.  

    The results shows that HR managers view on alcohol prevention was two-edged. They contribute to the preservation of existing alcohol norm but have policies to control soberness at work. Emerging themes were: Retention of existing alcohol norms and Alcohol-controlled working environment. But it was also a tendency of a preventive approach among some HR managers. 

    The results are in progress but the preliminary conclusion is that the double message from the manager to the seasonal workers with restrictions and control of alcohol use at work but invitations to drink in the evening is problematic and contribute to the norm of “party culture”.

  • 21598.
    Warne, Maria
    et al.
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Wall, Erika
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Svensson, Åsa
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Närvarande elever och positiv skolmiljö för ökat välbefinnande och måluppfyllelse i skolan: Slutrapport från forskarna i projekt Hälsofrämjande skolutveckling inom ramen för Skolverkets anslag för 2016-20172017Report (Other (popular science, discussion, etc.))
    Abstract [sv]

    Elevers närvaro i skolan är viktig både för deras kunskapsutveckling men även för deras hälsa och välmående idag och som vuxna. En betydelsefull faktor för närvaro är de sociala interaktioner som är en del av skolans vardag. Runt 20 000 elever hade 2015 olika formera av upprepad frånvaro och forskning visar att ströfrånvaro kan leda till långa perioder av frånvaro från skolan. Syftet med denna studie var att med utgångspunkt i ett pilotprojekt undersöka hur rutinerna kring rapportering och uppföljning av elevers frånvaro fungerade på två skolor i Östersunds kommun, en kommunal F–5-skola och en kommunal 6–9-skola, samt att identifiera hinder och framgångsfaktorer för elevers närvaro i skolmiljön. Erfarenheterna från projektet förväntades ge ökade kunskaper om orsaker till frånvaro och närvaro samt ge uppslag till interventioner som främjar närvaro och positiva sociala relationer i skolan. De metoder som användes var en analys av närvarorapporteringen och fokusgruppsintervjuer med elever i årskurs 9, vårdnadshavare, elevhälsopersonal på 6–9-skolan samt lärare på de två skolorna.Resultatet visar att det program som används för att rapportera närvaro på skolorna upplevs fungera bra men att det samtidigt skapar avstånd mellan vårdnadshavare och lärare. Sen ankomst och även när elever avviker från en lektion hanteras olika av olika lärare men även olika av samma lärare från gång till gång. Det finns en samstämmighet om ansvaret för elevers skolnärvaro, men eleverna upplever inte att skolan kan bidra med något om en elev inte vill gå till skolan. Det bedrivs enligt skolorna ett strukturerat arbete för likabehandling med elevhälsoplanen, och även andra strategier som syftar till ett närvarofrämjande arbete. Eleverna verkar dock inte så medvetna om det arbete som pågår utan behöver göras mer delaktiga. Relationerna mellan eleverna lyfts fram som viktiga för att främja närvaro i skolan av alla. Eleverna saknar dock en bättre relation mellan elever och lärare och ansvaret för dessa relationer kan inte ges till en annan yrkesgrupp, som till exempel fritidsledarna. Relationen mellan vårdnadshavare och skolpersonal upplevs ha brister och vårdnadshavare och skola verkar kommunicera mer digitalt än via personliga kontakter. Detta riskerar att fördjupa en frånvaroproblematik eller att tidiga signaler inte fångas upp. Också den fysiska miljön har betydelse för hur eleverna trivs på skolan. Slitna skolmiljöer och smutsiga toaletter sänder ut negativa signaler till eleverna och riskerar i sin tur att bidra till fortsatt förstörelse. Tillgång till en avkopplande miljö och återhämtning är viktiga faktorer för att främja närvaro. För ett fortsatta närvarofrämjande arbete behöver de sociala relationerna mellan framförallt elever och lärare förbättras liksom mellan vårdnadshavare och skola. Arbetet med strategier och bemötande kring sen ankomst och närvaro i klassrummet behöver utvecklas.

    The full text will be freely available from 2018-12-01 08:45
  • 21599.
    Warne, Maria
    et al.
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Wall, Erika
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Vinberg, Stig
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences.
    Managers’ and employees’ views of critical aspects for alcohol abuse prevention at small and medium enterprises: the case of ski resorts in NorthernSweden2017In: Society, health and vulnerability, E-ISSN 2002-1518, Vol. 8, no sup1, p. 67-79, article id UNSP 1355719Article in journal (Refereed)
    Abstract [en]

    Seasonal workers at tourism resorts, particularly young employees, represent a high-riskpopulation for alcohol abuse and other negative lifestyles. This study explores how managers and employees at ski resorts in Northern Sweden experience critical aspects for hazardous alcohol use at small- and medium-sized enterprises. This analysis is based on one open-ended question about hazardous alcohol use prevention at the workplace answered by 153 employees,and semi-structured interviews about being a manager at a ski resort conducted with 13managers. The analysis showed that managers’ views regarding hazardous alcohol use prevention were double-edged, which was confirmed by the employees’ answers. The managers contribute to the preservation of existing alcohol norms but simultaneously enforce policies and administer tests to control employees’ sobriety at work. Three themes emerged: reproducing existing alcohol norms, an alcohol-controlled working environment and care-taking managers. The results identified a need for early prevention initiatives focusing on the norms and work cultures of small- and medium-sized ski resorts. In relation to the theory of planned behaviour, the analysis illuminates how evaluations of behaviours related to alcohol consumption are communicated in policies and through leadership. In addition, the importance of social pressure regarding alcohol use is clarified in the material.

  • 21600.
    Warner, Grace
    et al.
    Dalhousie Univ, Sch Occupat Therapy, POB 15000, Halifax, NS B3H 4R2, Canada.
    Packer, Tanya
    Dalhousie Univ, Sch Occupat Therapy, POB 15000, Halifax, NS B3H 4R2, Canada.
    Villeneuve, Michelle
    Univ Sydney, Fac Hlth Sci, Sydney, NSW 2006, Australia.
    Audulv, Åsa
    Mid Sweden University, Faculty of Human Sciences, Department of Health Sciences. Dalhousie Univ, Sch Occupat Therapy, POB 15000, Halifax, NS B3H 4R2, Canada.
    Versnel, Joan
    Dalhousie Univ, Sch Occupat Therapy, POB 15000, Halifax, NS B3H 4R2, Canada.
    A systematic review of the effectiveness of stroke self-management programs for improving function and participation outcomes: self-management programs for stroke survivors2015In: Disability and Rehabilitation, ISSN 0963-8288, E-ISSN 1464-5165, Vol. 37, no 23, p. 2141-2163Article in journal (Refereed)
    Abstract [en]

    Purpose: A systematic review of stroke self-management programs was conducted to: (i) identify how many and what self-management support strategies were included in stroke selfmanagement interventions and (ii) describe whether self-management programs effectively improved outcomes, focusing specifically on function and participation outcomes. Methods: Twelve databases were searched for the years 1986–2012 to identify self-management programs for stroke survivors. Pre-post, quasi-experimental and randomized controlled trial study designs were included. Descriptive information about the intervention was scrutinized to identify what self-management support strategies were present in the intervention and comparisons were made between programs using a group versus a one-to-one format. All outcomes were included and categorized. Results: The most prominent strategies identified in our review were goal setting and follow-up, and an individualized approach using structured information and professional support. There are indications that self-management programs can significantly increase participation and functional ability. However, the high level of clinical heterogeneity in program delivery, outcomes and level of stroke severity made it impossible to conduct a meta-analysis. Further examination of individual self-management support strategies, such as linking rehabilitation goal setting to post-acute self-management programs, the inclusion of family members and the contribution of peer-support is warranted.

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