| 1. |
- Granlund, Daniel, et al.
(författare)
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Project: BASICNET
- 2008
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Annan publikation (populärvet., debatt m.m.)abstract
- Broadband Access Services In Converging NETworks
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| 2. |
- Idowu, Samuel, et al.
(författare)
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Machine Learning in Pervasive Computing
- 2013
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Increase in data quantities and number of pervasive systems has resulted in many decision-making systems. Most of these systems employ Machine Learning (ML) in various practical scenarios and applications. Enormous amount of data generated by sensors can be useful in decision-making systems. The rising number of sensor driven pervasive systems presents interesting research areas on how to adapt and apply existing ML techniques effectively to the domain of pervasive computing. In the face of data deluge, ML has proved viable in many application areas such as data mining and self-customizing programs and could bring about great impact in the field of pervasive computing.The objective of this study is to give the underlying concepts of ML techniques that can be applied to problems in the domain of pervasive and mobile computing. The scope of this study covers the three primary types of ML, supervised, unsupervised and reinforcement learning methods. In the process of providing the fundamental knowledge of ML, we present some conceptual terms of ML and the steps required in developing ML system with a great impact on domains outside ML scope.Our findings show that previous works in the area of ubiquitous computing have successfully applied supervised learning and reinforcement learning methods. Hence, this study focuses more on supervised learning and reinforcement learning. In conclusion, we discuss some basic performance evaluation metrics and methods for obtaining reliable classifiers estimates, such as cross-validation and leave-one-out validation.
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| 3. |
- Schelén, Olov, et al.
(författare)
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A sensor-data acquisition grid architecture
- 2013
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Ingår i: 2013 IEEE International Conference on Networking, Sensing and Control. - Piscataway, NJ : IEEE Communications Society. - 9781467351997 - 9781467351997 ; , s. 361-366
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Konferensbidrag (refereegranskat)abstract
- This paper presents SAGA, a functional software architecture for distributing sensor data. The recursive architecture is dynamically instantiated for collecting, composing and storing data at multiple locations. Objectives are to support devices that are intermittently connected over different access-technologies, to save energy by avoiding repetitive transmission from sensors, and to scale out data compositions for different application services. When the architecture is instantiated the entities form a directed graph across organizational boundaries between sensors and applications. Data may be retrieved from sensors on-demand or be disseminated in real-time, for composition and delivery to the applications. The architecture is based on current sensor network principles such as client-server, representational state transfer and web services. The architecture is presented together with identified key requirements and design choices, and it has been instantiated in a prototype implementation for a smart city application. Some key issues for further research are presented.
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| 4. |
- Schmidt, Mischa
(författare)
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EVOX-CPS : A Methodology For Data-Driven Optimization Of Building Operation
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Existing building stock’s energy efficiency must improve due to its significant proportion of the global energy consumption mix. Predictive building control promises to increase the efficiency of buildings during their operational phase and thus lead to a reduction of the lion’s share of buildings’ lifetime energy consumption. Predictive control complements other means to increase performance, such as refurbishments as well as modernization of systems.This thesis contributes EVOX-CPS, a holistic methodology to develop data-driven predictive control for (existing) buildings and deploy the control in day-to-day use. EVOX-CPS evolves buildings into Cyber-Physical Systems and addresses the development of data-driven predictive control using computational methods. The thesis’ focus rests on accounting for the situation of existing buildings - which vary greatly regarding their physical characteristics, usage patterns, system installation, and instrumentation levels. The methodology addresses the aspect of building stock variety with its capability to flexibly adapt to different buildings’ characteristics, e.g., by supporting the integration of varying levels of pre-existing building instrumentation. Furthermore, EVOX-CPS supports using different data mining, regression, or control techniques (i) to strengthen the support for a variety of buildings, and (ii) to cater to researchers’ and practitioners’ differing skills, experiences, or preferences concerning different data analysis techniques. Through its flexibility, the methodology addresses a vast potential installation base and lowers the barriers for adoption in day-to-day use, e.g., by being able to leverage prior investments in building instrumentation and supporting different data-analysis techniques. At the same time, EVOX-CPS provides researchers and practitioners with comprehensive guidance relevant to their daily work. Besides, EVOX-CPS supports addressing a building’s known limitations in the daily operation, e.g., uncomfortable indoor conditions.The experimentation in two real buildings validates the effectiveness of EVOX-CPS’ data-driven control with high reliability due to prolonged experimentation periods combined with applying energy normalization and inferential statistics. The experiments during routine heating system operation establish high confidence in the recorded effect sizes: the improvements in operational efficiency are profound and statistically significant. More specifically, the experiments of controlling the grass heating system of the soccer stadium Commerzbank Arena, Frankfurt, Germany, in two winters saved up to 66% (2014/2015) and 85% (2015/2016) of energy consumption. Extrapolation to an average heating season leads to expected savings of 775 MWh (148 t of CO2 emissions) and 1 GWh (197 t CO2), respectively. The experiments also show that EVOX-CPS allowed alleviating the known operational limitation of heating supply shortages which required nightly preheating in the stadium’s standard operating procedures. In another set of experiments, we applied the methodology to control the heating system of the Sierra Elvira School in Granada, Spain. The experimentation occurred during the regular class hours of 43 school days in winter 2015/2016. A first experiment demonstrated the possibility to lower consumption by one-third while maintaining indoor comfort. Another experiment raised average indoor temperatures by 2K with 5% additional energy consumption. Again, that illustrates EVOX-CPS’ capability to address a building’s known operational issues.
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| 5. |
- Jingili, Nuru, et al.
(författare)
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A Two-Stage co-Design Process of Battleship-AST Persuasive Game for Active School Transportation in Northern Sweden
- 2024
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Ingår i: International Journal of Human-Computer Interaction. - : Taylor & Francis. - 1044-7318 .- 1532-7590.
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Tidskriftsartikel (refereegranskat)abstract
- This research delves into the dynamics of active school transport (AST) by utilizing a two-stage co-design process and leveraging persuasive technology within a game for promoting AST called Battleship-AST. The primary aim of this research is to thoroughly investigate the two-stage game co-design process employed in creating a Battleship-AST game. Moreover, our research aims to evaluate participants’ perceptions regarding the motivating and engaging potential of the persuasive technology and gamification features embedded within the final iteration of the game. This evaluation aims to understand how these features influence participants’ motivation to increase their usage of AST through gameplay. In pursuit of these objectives, the research builds upon the existing Battleship-AST prototype and actively engages school children in a collaborative two-stage co-design process. Their valuable insights and preferences were harnessed in refining the game, which was subsequently tested during a tech event in Skellefteå, Sweden. The findings shed light on various aspects of the game’s impact, from its reception to the gamification features integrated within. Notably, the research highlights the positive impact of the co-design process, with increased motivation and engagement observed among the participants. Their involvement in shaping the game’s design resulted in a more engaging and enjoyable experience. The persuasive technology features, encompassing competition, collaboration, auditory cues, a virtual reward system, and an emphasis on similarity, played a pivotal role in sustaining engagement and motivating players. Elements such as rewards, leaderboard progression, and badges proved highly effective in encouraging continued participation and fostering a positive feedback loop. However, the study also identifies areas for potential improvement, including the need to measure real-life progress and refine the game’s levelling system. The research indicates that refining feedback mechanisms and tailoring game content to individual preferences could create an even more engaging experience. Additionally, long-term playtesting is proposed to assess the game’s extended impact. The findings offer promising avenues for enhancing motivation and engagement in AST, which can contribute to the promotion of healthier and more sustainable transportation choices among school children.
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| 6. |
- Brännström, Robert, et al.
(författare)
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Implementing global connectivity and mobility support in a wireless multi-hop ad hoc network
- 2006
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Ingår i: Proceedings of the 4th Asian International Mobile Computing Conference.
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Konferensbidrag (refereegranskat)abstract
- Pervasive access to the Internet is driven by users who want wireless connectivity to ad hoc as well as infrastructure networks. Multi-hop wireless connectivity widens the coverage areas of access networks and enables two-way wireless traffic into previously dead-spot areas. This paper addresses network mobility issues, which are essential for roaming users who connect to the Internet through wireless access networks. We propose to support connectivity to wired infrastructure through multiple gateways with possibly different capabilities and utilization. Increased network performance can be achieved by adapting to variations in performance and coverage and by switching between gateways when beneficial. We present an efficient solution to enable ad hoc access to the Internet as well as interoperation of reactive routing protocols with Mobile IP. Our solution combines the benefits of proactive agent advertisement and reactive route discovery into a flexible multi-hop access network. We also discuss wireless network metrics that can be used for more intelligent decision making on gateway selection. The feasibility of our approach is validated by simulation and implementation.
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| 7. |
- Brännström, Robert, et al.
(författare)
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Maintaining gateway connectivity in multi-hop ad hoc networks
- 2005
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Ingår i: Proceedings. - Los Alamitos, Calif : IEEE Computer Society Press. - 0769524214 ; , s. 682-689
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Konferensbidrag (refereegranskat)abstract
- The need for maintaining gateway connectivity in an ad hoc access network is vital considering the 80/20 ratio of Internet traffic. There are several proposals of how to integrate gateway forwarding strategies but they all rely on the route discovery procedure of reactive routing protocols. We propose a proactive approach to avoid the delay of the route discovery process. Mobile IP is often suggested to handle macro mobility and we use the advertisements periodically sent by the gateway to update routing tables in the ad hoc network. Since advertisements may arrive to a mobile host through multiple paths, it is important to keep track of the best path to each gateway. We demonstrate the use of a proposed dynamic metric and how to handle location of correspondent hosts. A simulation study demonstrates the usefulness and efficiency of our approach.
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| 8. |
- Brännström, Robert, et al.
(författare)
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Mobility management for multiple diverse applications in heterogeneous wireless networks
- 2006
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Ingår i: New technologies for consumer networking and communications: eliminating boundaries. - Piscataway, NJ : IEEE Communications Society. - 1424400856 ; , s. 818-822
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Konferensbidrag (refereegranskat)abstract
- This paper presents a mobility management solution to support both applications who are mobility-aware and those who are not. Mobility management in heterogeneous network environments needs to address the double meaning of the IP address as an endpoint identifier and a location identifier. Application-layer mobility use a non-IP endpoint identifier (e.g. user @ realm) while network-layer mobility uses a fixed home IPaddress as endpoint identifier. The resolving of the endpoint identifier to a temporary unicast IP address as location identifier needs support from a mobility management system. This paper proposes a mobility support system that integrates the benefits of application-layer SIP mobility with network-layer MIP mobility. A cross-layer information system provides context for mobility adaptation. Context awareness enhances handover decisions, transport performance and media adoption. The network-layer mobility supports the application to locate the destination ondemand for the initial setup of the sessions. The paper includes an initial evaluation of the network-layer mobility part of the solution.
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| 9. |
- Brännström, Robert
(författare)
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Mobility management in heterogeneous access networks
- 2007
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis proposes, describes and validates solutions to enhance mobility in heterogeneous access networks. Wireless access networks have become available almost everywhere and current research strives to make them pervasive. Users having wireless access to the Internet are driving the demand for mobile and heterogeneous solutions where services could be accessed from anywhere, any time and from any device. Future wireless connectivity will be provided through a mix of coexisting heterogeneous access network technologies. To enhance mobility in heterogeneous networks this thesis focuses on mobility management systems and connectivity of wireless multi-hop ad hoc networks to the Internet. In a wireless environment with overlapping service areas, mobile nodes need to select which gateway(s) to use to access the wireless infrastructure. The metrics used to select the point of attachment within an access technology are insufficient to compare the capacity of different technologies or multi-hop routes. This thesis proposes, describes and validates solutions to calculating network layer metrics and using them in gateway selection and handover decisions. To enable connectivity of a mobile ad hoc network (MANET) to the Internet, a gateway must bridge the wired single-hop and wireless multi-hop approaches. A MANET enables connectivity to more than one gateway at a time and combined with multihoming it provides seamless handover between subnets. The gateway selection and handover decisions are complicated by the multihoming capabilities. Connectivity to Internet services makes it important to maintain the efficient route to the gateway. It is also important to identify the location of a destination to separate the management of Internet and intra MANET destinations. This thesis proposes,describes and validates solutions to deploying multihomed mobility into MANETs and thereby handling multi-hop gateway discovery, registration of multiple gateways and tunneling to selected gateway(s). The solution maintains gateway connectivity in MANETs by installing routes to gateways using advertisements and manages route discovery based on the destination locality. Both applications with mobility awareness (e.g. SIP phones) and those without it must be supported by a mobility management system. The existence of network layer mobility management can enhance an application layer system. This thesis proposes, describes and validates deployment of a mobility management system with support of both application and network layer mobility. With wireless access networks some technologies might not support some types of applications and a single technology might not cope with all the application demands from a mobile node. Thus the control of individual traffic flows could be used to share the load on multiple access technologies and to direct flows over specified technologies. This thesis proposes, describes and validates solutions to identification and mobility management of individual traffic flows in a heterogeneous network environment. Finally this thesis proposes, describes and validates a deployment proposal of route evaluation and flow control to enable load balancing in wireless multi-hop networks.
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| 10. |
- Brännström, Robert, et al.
(författare)
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Multimedia flow mobility in heterogeneous networks using multihomed mobile IP
- 2007
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Ingår i: Journal of Mobile Multimedia. - 1550-4646 .- 1550-4654. ; 3:3, s. 218-234
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Tidskriftsartikel (refereegranskat)abstract
- Communication in next generation networks will use multiple access technologies, creating a heterogeneous network environment. To enable end-user terminals to move between access networks with minimal disruption, the terminals should be able to maintain multiple active network connections. Such a multihomed mobile host will experience differences in capabilities and coverage area depending on the access technologies. This paper proposes and evaluates an extension to Mobile IP enabling multihoming, regardless of the access technology. Mobility of multimedia communication in this environment should adapt to changing conditions and be based on dynamic measurements and user preferences. The proposed architecture gives opportunities for mobile multimedia applications to use multiple access networks simultaneously and the possibility to move individual flows between access networks and between user devices. Media flows are identified by destination IP address, protocol and port number. Evaluation results are presented both from a simulation study and from a real world prototype implementation using three different wireless access technologies: 802.11, UMTS and 802.16-2004.
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