| 61. |
- Bilstrup, Katrin, et al.
(författare)
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Medium access control in vehicular networks based on the upcoming IEEE 802.11p standard
- 2008
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Ingår i: 15th World Congress on Intelligent Transport Systems and ITS America Annual Meeting 2008. - : World Congress on ITS. - 9781615677566 ; , s. 4155-4167, s. 12-
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Konferensbidrag (refereegranskat)abstract
- In this paper, initial simulations are presented showing that the upcoming IEEE 802.11p standard is not suitable for traffic safety applications requiring reliable, low delay communication between vehicles. The medium access control procedure is one of the most important parts in the design of delay-constrained communication systems, and emerging vehicle safety applications put new stringent demands on timely and reliable delivery of data packets. The medium access procedure used in 802.11p is carrier sense multiple access, which is inherently unsuitable for time-critical data traffic since it is contention-based and cannot provide a finite upper bound on the time to channel access. The simulation results indicate that with IEEE 802.11p, channel access cannot be granted in a manner that is sufficiently predictable to support reliable, low-delay communications between vehicles on a highway.
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| 62. |
- Bilstrup, Urban, 1971-
(författare)
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Bluetooth and Wireless Multihop Networks in Industrial Communication Systems
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The objective of this thesis is to investigate the use of short-range wireless communication technology in industrial communication systems where there is a need for guaranteed timely delivery of correct information. Methods for achieving such capability are developed in the context of the physical layer, the data link layer and the application layer. Based on the insight that it is impossible to achieve strict determinism in a wireless communication system, a probabilistic definition of hard real-time systems is suggested, and thus a guarantee is given in the form of the probability of fulfilling a certain goal. Since a wireless channel is time variant, it is also necessary to continuously keep track of available resources. Allocation and link management methods for wireless communication systems therefore need to be dynamic and of an online character. An exhaustive resource allocation method with redundancy is first proposed for single message delivery and then extended for the operation of a single Bluetooth piconet. However, many devices in an industrial automation system have limited computational resources, especially if wireless sensors/actuators powered by battery or wireless power are considered. This implies that methods used for resource allocation must be of low computational complexity. The complexity issue becomes evident when large systems are implemented, even if each individual sensor generates small amounts of data. The upstream and downstream flows of data grow rapidly in a hierarchical system with many sub-systems, sensors and actuators. It is empirically shown that the aggregated data flow in a monitoring system requires powerful communication nodes already at low levels in the industrial communication hierarchy. A predictable system requires that representative entities for the available resources are defined. In a communication system with a single broadcast domain, such as a single Bluetooth piconet, the resource space is often limited to the time domain. When a multihop wireless network with multiple broadcast domains is considered, the spatial domain is added as an available resource and, if a multi-channel radio transceiver is used, the frequency is also added as an available resource domain. These three domains represent the physical resource space that is available for a wireless multihop network. These are subject to trade-off in all of the three lowest protocol layers, and one of the most challenging problems in the design of a wireless multihop network is how to achieve efficient sharing of these resources. This problem is addressed by proposing a clustered architecture based on a dual-radio node that enables dynamic use of these resource domains.
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| 63. |
- Binotto, Alécio P. D., et al.
(författare)
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Dynamic Self-Rescheduling of Tasks over a Heterogeneous Platform
- 2008
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Ingår i: Proceedings of the 2008 International Conference on Reconfigurable Computing and FPGAs. - Los Alamitos, Calif. : IEEE Computer Society. - 9780769534749 ; , s. 253-258
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Konferensbidrag (refereegranskat)abstract
- Modern applications require powerful high-performance platforms to deal with many different algorithms that make use of massive calculations. At the same time, low-cost and high-performance specific hardware (e.g., GPU, PPU) are rising and the CPUs turned to multiple cores, characterizing together an interesting and powerful heterogeneous execution platform. Therefore, self-adaptive computing is a potential paradigm for those scenarios as it can provide flexibility to explore the computational resources on heterogeneous cluster attached to a high-performance computer system platform. As the first step towards a run-time reschedule load-balancing framework targeting that kind of platform, application time requirements and its crosscutting behavior play an important role for task allocation decisions. This paper presents a strategy for self-reallocation of specific tasks, including dynamic created ones, using aspect-oriented paradigms to address non-functional application timing constraints in the design phase. Additionally, as a case study, a special attention on Radar Image Processing will be given in the context of a surveillance system based on Unmanned Aerial Vehicles (UAV).
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| 64. |
- Binotto, A.P.D., et al.
(författare)
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Real-time task reconfiguration support applied to an UAV-based surveillance system
- 2008
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Ingår i: 2008 International Multiconference on Computer Science and Information Technology (Imcsit). - Piscataway, N.J. : IEEE Press. - 9788360810149 ; , s. 581-588
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Konferensbidrag (refereegranskat)abstract
- Modern surveillance systems, such as those based on the use of Unmanned Aerial Vehicles, require powerful high- performance platforms to deal with many different algorithms that make use of massive calculations. At the same time, low- cost and high-performance specific hardware (e.g., GPU, PPU) are rising and the CPUs turned to multiple cores, characteriz- ing together an interesting and powerful heterogeneous execu- tion platform. Therefore, reconfigurable computing is a poten- tial paradigm for those scenarios as it can provide flexibility to explore the computational resources on heterogeneous cluster attached to a high-performance computer system platform. As the first step towards a run-time reconfigurable workload bal- ancing framework targeting that kind of platform, application time requirements and its crosscutting behavior play an impor- tant role for task allocation decisions. This paper presents a strategy to reallocate specific tasks in a surveillance system composed by a fleet of Unmanned Aerial Vehicles using aspect- oriented paradigms in order to address non-functional applica- tion timing constraints in the design phase. An aspect support from a framework called DERAF is used to support reconfigu- ration requirements and provide the resource information needed by the reconfigurable load-balancing strategy. Finally, for the case study, a special attention on Radar Image Process- ing will be given.
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| 65. |
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| 66. |
- Björk, Peter, 1981-
(författare)
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Konstruktiv eller moralisk kritik? : Reflektioner om villkor för kommunikation och lärande kring krisberedskap och krishantering
- 2008
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Ingår i: Säkerhet och sårbarhet. - Halmstad : Högskolan i Halmstad. - 9197481947 ; , s. 139-148
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Texten innehåller några reflektioner på Säkerhets- och sårbarhetskonferensen vid Högskolan i Halmstad den 17 april 2008. Syftet är att lyfta fram och diskutera en aspekt av problematiken i forsknings- och utvecklingsarbetet kring krisberedskap och krishantering; nämligen de diffusa och komplexa gränserna mellan å ena sidan en moralisk och å andra sidan en konstruktiv form av kritik.
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| 67. |
- Björkén-Nyberg, Cecilia, 1962-
(författare)
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Dear?, Am I Truly Yours? : Private Correspondence as a Field of Public Meanings
- 2008
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Writing a life necessarily means that the dichotomy public/private is actualised. Even the most private matters are made public as soon as they are put into the public medium of writing. As is a well-known fact, for a woman writing in the 19th century this transition from private to public was particularly problematic. In order to handle it, many female writers adopted a male pseudonym in order to gain acceptance in the public arena. What was more unusual for a woman was to keep up a male persona in private correspondence.In 1910 the Australian novelist Henry Handel Richardson (pseudonym for Ethel Lindsay Richardson) was contacted by the French man of letters Paul Solanges whose aim was to translate her first novel Maurice Guest (1908). In the ensuing correspondence spanning almost four years she never dropped the male mask. In the proposed paper I want to demonstrate the complex web of gendered position-taking in the letters they exchanged, which in the end proved that both their lives were entrapped in writing.
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| 68. |
- Blomkvist, Marita, 1959-
(författare)
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Entreprenörer som redovisare : bokslutsprocessen i Gasellföretag
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Entrepreneurs seem to be highly valuable for the firms in which they are involved. However, the knowledge of the role of accounting in a context of entrepreneurship is limited. In fact, some literature on entrepreneurship indicates that the role of accounting is only about the past and therefore not of interest for entrepreneurs in the entrepreneurial process.This dissertation reports the results of two empirical studies. The first study is a qualitative pilot study of five entrepreneurs in fast growing firms and their participation in the year-end procedure. The respondents were presented the adjustments in the final step of the recording process and the annual report in order to assess their participation and to focus on how the entrepreneurs as producers of accounting reflect and act in relation to other actors and to the process of reporting. The pilot study found that the entrepreneurs were certainly involved in use and produce of certain accounting in the year-end procedures. The second study is based on the result from the pilot study and on agency theory the study aimed to describe and explain how and why entrepreneurs in successful fast growing firms, i.e. Gazelle firms, compared with a control group of managers in not growing firms, are participating in the year-end procedures. Also, the study aimed to analyse differences between entrepreneurs´ participation and other managers´ participation in this process. The study focused on the activities in the year-end procedures concerned with the values of R&D, stock and work-in-progress and accounts receivables. In order to find entrepreneurs the survey was sent to a sample of 257 managers of Gazelle firms and to a sample of 227 managers in not growing firms. Also, the annual report from the firms where the respondents where involved were collected. This data was also included in the study. The responding rate was 50% from both groups. The most notable finding is, in contradiction to literature on entrepreneurship, that entrepreneurs in Gazelle firms use and produce formal financial accounting information. Entrepreneurs in Gazelle firms spend more time and they are also involved in discussions with more actors compared with managers in not growing firms. Further, the results indicate that entrepreneurs in Gazelle firms will participate to a larger extent when the profitability in the firm decreases compared to managers in not growing firms. Finally, the dissertation gives insight in the role of formal financial accounting in the context of entrepreneurship, a research area we know little about.
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| 69. |
- Bollou, Felix, et al.
(författare)
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Are ICT investments paying off in Africa? : An Analysis of total factor productivity in six West African Countries from 1995 to 2002
- 2008
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Ingår i: Information Technology for Development. - Abingdon, Oxon, UK : Routledge. - 0268-1102 .- 1554-0170. ; 14:4, s. 294-307
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Tidskriftsartikel (refereegranskat)abstract
- In the past two decades, we have seen increasing debate about information and communication technology (ICT) as an engine of growth that could lift developing nations out of poverty. Many African nations have implemented market liberalization and invested huge sums of money into their ICT sectors. But few studies have been conducted to assess the effectiveness of these investments. Demonstrating ICT sector performance is especially important because of challenges of the development of ICT policy and the United Nations agencies inability to state firmly if there are benefits to these investments. In this article, we investigated the total factor productivity (TFP) of the ICT sectors in six West African countries from 1995 to 2002. While the findings demonstrate positive growth in TFP, there is cause for concern. TFP growth in the ICT sector has been declining, and these countries are not yet able to take advantage of scale efficiencies. Careful attention must be given to future ICT investment strategies and performance management of existing ICT infrastructure if continued growth is to be achieved. © 2008 Wiley Periodicals, Inc.
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| 70. |
- Bolmsjö, Gunnar, et al.
(författare)
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Robot assisted framing : A concept for securing geometry in flexible production
- 2008
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Rapport (refereegranskat)abstract
- The paper describes a concept for securing the geometry in flexible production based on robot assisted framing. This uses the robot(s) as an active device during change-over between product variants and it is assumed that product variants can be produced in any mixed order. The case under study is cabs for trucks which in traditional production require large and heavy equipment which is above the payload of any robot. The idea within this study is to use carbon fibre composites in the fixtures in order to reduce the weight and through this make it possible to use the robots in assisting the framing process. The current work involves a generalization of the principle both considering the design of the fixtures with respect to issues such as materials properties and design principles, and design of the production system.
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