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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
351

Heavy Vehicle Classification Analysis Using Length-Based Vehicle Count and Speed Data

Yuksel, Eren 27 June 2018 (has links)
There is an increasing demand for application of Intelligent Transportation Systems (ITS) in order to make highways safer and sustainable. Collecting and analyzing traffic stream data are the most important parameters in transportation engineering in enhancing our understanding of traffic congestion and mobility. Classification of the vehicles using traffic data is one of the most essential parameters for traffic management. Of particular interest are heavy vehicles which impact traffic mobility due to their lack of maneuverability and slower speeds. The impact of heavy vehicles on the traffic stream results in congestion and reduction of road efficiency. In this paper, length-based vehicle count and speed data were analyzed and interpreted using one week's data from Interstate 5 (I-5) in the Portland, Oregon (OR) region of the United States (US). I-5 was chosen due to its prominent role in promoting North-South freight movement between Canada and Mexico and its vicinity to the Port of Portland. The objective of this analysis was to find better visualization techniques for the length-based traffic count and speed data. In total, 13,901,793 out of 56,146,138 20-second records were analyzed. The vehicles were classified into two categories. Those that were 20 feet or less were considered as passenger vehicles and those above 20 feet were considered as heavy vehicles. The data consisted of approximately 25% heavy vehicles. Results showed the merit of applying more disaggregate data (5-min polar, and radar plots) for better visualization as against hourly, and 15-min plots in order to capture sudden changes in average speed, heavy vehicle volume, and heavy vehicle percentage.
352

Caching dynamic data for web applications

Mahdavi, Mehregan, Computer Science & Engineering, Faculty of Engineering, UNSW January 2006 (has links)
Web portals are one of the rapidly growing applications, providing a single interface to access different sources (providers). The results from the providers are typically obtained by each provider querying a database and returning an HTML or XML document. Performance and in particular providing fast response time is one of the critical issues in such applications. Dissatisfaction of users dramatically increases with increasing response time, resulting in abandonment of Web sites, which in turn could result in loss of revenue by the providers and the portal. Caching is one of the key techniques that address the performance of such applications. In this work we focus on improving the performance of portal applications via caching. We discuss the limitations of existing caching solutions in such applications and introduce a caching strategy based on collaboration between the portal and its providers. Providers trace their logs, extract information to identify good candidates for caching and notify the portal. Caching at the portal is decided based on scores calculated by providers and associated with objects. We evaluate the performance of the collaborative caching strategy using simulation data. We show how providers can trace their logs and calculate cache-worthiness scores for their objects and notify the portal. We also address the issue of heterogeneous scoring policies by different providers and introduce mechanisms to regulate caching scores. We also show how portal and providers can synchronize their meta-data in order to minimize the overhead associated with collaboration for caching.
353

The Role of Information and Communication Technologies in Knowledge Management: From Enabler to Facilitator

Song, Hongli, hongli.song@rmit.edu.au January 2007 (has links)
This study focuses on the role of Information and communication technology (ICT) in support of effective knowledge management. Based on a comprehensive literature review, a knowledge management framework was developed for investigating the role of ICT in support of knowledge management. The framework not only centers on the dynamics of knowledge objects and processes, but also focuses on the impact of the internal knowledge management environment where organizational, managerial, structural, cultural and other related elements are intertwined and interplayed. Based on this research framework, two sets of hypotheses were proposed for testing: (a) whether ICT enables and facilitates conversions between knowledge objects and knowledge management processes, and (b) whether the internal knowledge management environment impacts the effective implementation of knowledge management projects. To test the hypotheses, a combination of qualitative and quantitative research methodologies including theoretical induction, continuous literature review, secondary data analysis, and the conduct of an online questionnaire survey and a case study was adopted in this study. The empirical findings were drawn from the secondary data analysis, case study and questionnaire survey. A questionnaire survey and a case study were conducted to obtain empirical data for testing and validating research hypotheses. To obtain a better understanding of current knowledge management best practices, secondary data were gathered and analyzed. In order to investigate the conversion processes of knowledge objects, an online survey was used to explore the experience, perceptions and opinions of respondents in the use of electronic resources at an individual level. To identify the factors that can determine success or failure in implementing knowledge management projects, a case study involving the pilot implementation of a knowledge portal was undertaken for collecting and analyzing empirical evidence from the field. The empirical findings confirm the ICT's enabling role in knowledge management. The results of this study further suggest that the conversion processes between data and information are fully supported by ICT, whereas the conversion processes between data and knowledge, and the conversion processes between information and knowledge are only partially supported by ICT. While knowledge codification and dissemination are increasingly supported by ICT, supportive technology for knowledge generation and application remains much less effective. The critical success factors impacting the implementation of knowledge management projects include organizational, structural, strategical, managerial, and cultural elements. These interlocking elements form the internal knowledge management environment in an organization. This study provides theoretical contributions by better understanding the nature of knowledge, the relationship between ICT and knowledge management, and the relationship between knowledge management and internal knowledge management environment. It also provides a contribution relevant to practitioners by developing a novel knowledge management framework, which can be used as a guideline of knowledge management efforts.
354

New Efficient Detector for Radiation Therapy Imaging using Gas Electron Multipliers

Östling, Janina January 2006 (has links)
<p>Currently film is being replaced by electronic detectors for portal imaging in radiation therapy. This development offers obvious advantages such as on-line quality assurance and digital images that can easily be accessed, processed and communicated. In spite of the improvements, the image quality has not been significantly enhanced, partly since the quantum efficiency compared to film is essentially the same, and the new electronic devices also suffer from sensitivity to the harsh radiation environment. In this thesis we propose a third generation electronic portal imaging device with increased quantum efficiency and potentially higher image quality.</p><p>Due to the parallel readout capability it is much faster than current devices, providing at least 200 frames per second (fps), and would even allow for a quality assurance and adaptive actions after each accelerator pulse. The new detector is also sensitive over a broader range of energies (10 keV - 50 MeV) and can be used to obtain diagnostic images immediately prior to the treatment without repositioning the patient. The imaging could be in the form of portal imaging or computed tomography. The new detector is based on a sandwich design containing several layers of Gas Electron Multipliers (GEMs) in combination with, or integrated with, perforated converter plates. The charge created by the ionizing radiation is drifted to the bottom of the assembly where a tailored readout system collects and digitizes the charge. The new readout system is further designed in such a way that no sensitive electronics is placed in the radiation beam and the detector is expected to be radiation resistant since it consists mainly of kapton, copper and gas.</p><p>A single GEM detector was responding linearly when tested with a 50 MV photon beam at a fluence rate of ~10<sup>10</sup> photons mm<sup>-2</sup> s<sup>-1</sup> during 3-5 μs long pulses, but also with x-ray energies of 10-50 keV at a fluence rate of up to ~10<sup>8</sup> photons mm<sup>-2</sup> s<sup>-1</sup>. The electron transmission of a 100 μm thick Cu plate with an optical transparency of ~46% was found to be ~15.4%, i.e. the effective hole transmission for the electrons was about one third of the hole area. A low effective GEM gain is enough to compensate for the losses in converters of this dimension. A prototype for the dedicated electronic readout system was designed with 50 x 100 pixels at a pitch of 1.27 mm x 1.27 mm. X-ray images were achieved with a single GEM layer and also in a double GEM setup with a converter plate interleaved. To verify the readout speed a Newton pendulum was imaged at a frame rate of 70 fps and alpha particles were imaged in 188 fps. The experimental studies indicates that the existing prototype can be developed as a competitive alternative for imaging in radiation therapy.</p>
355

Kunskapsnätverkande / Knowledge Networking

Larsson, Thomas, Lindskog, Mats January 2005 (has links)
<p>Competence Portals are software tools that are intended to make it easier for persons that have had no previous contact to find and contact each other. The portals can address areas ranging from finding an expert within an organisation to the marketing of the competence of a region or a research centre to other organisations. </p><p>The purpose of the thesis is to examine the necessity of Competence Portals in research-intensive organisations. Important characteristics of the information in such portals have been identified and used as a basis for recommendations regarding how Competence Portals could be designed. Furthermore, the thesis focuses on the task of finding a source of knowledge within an organisation. </p><p>The study is of a general nature and is supposed to be of interest to anyone who has an interest in knowledge management and tools to enable easy contacts within and between organisations. The study includes research organisations from Sweden, Germany and the United Kingdom and privately owned Swedish companies. The focus is on the German research organisations and Swedish companies. The empirical data was gathered using two surveys and multiple interviews with both persons featured in a Competence Portal as well as prospective users. </p><p>We have found that is uncommon to have access to tools such as Competence Portals in the studied groups. The tasks that a portal is meant to make easier is most often already solved in an efficient way or not performed frequently enough to merit a larger investment. Furthermore, the general opinion regarding Competence Systems in the studied group is very sceptical. We have therefore reached the conclusion that the demand for a software solution such as Competence Portals is low in the studied group. As a result of the little room for improvement in current work procedures and a general low demand we conclude that the necessity of Competence Portals is low in the studied group. However, Competence Portals are likely to be useful to very large or geographically scattered organisations. We have summarized our findings regarding the quality aspects of the information inCompetence Portals in a model that illustrates the important areas to consider when designing a Competence Portal. The model emphasise the importance of processes for updating and maintaining the information in the portal.</p>
356

Värdering av Internetportaler : en studie av värdebyggande faktorer vid värdering av portaler

Lundevall, Jenny, Åström, Maria January 2000 (has links)
<p>Många Internetrelaterade företag har den senaste tiden på börser runt om i världen värderats till flera miljarder kronor. Internetföretag utan vinst eller historia är svåra att värdera med traditionella värderingsmetoder och därför krävs andra tillvägagångssätt för värdering. Syftet är att beskriva vilka faktorer som påverkar värderingen av Internetportaler samt att med hjälp av dessa faktorer försöka värdera en portal. Undersökningen är dels teoretisk och behandlar avsaknaden av fungerande modeller för portal-värdering, dels rör problemet vårt fallföretag, på vilket vi försöker applicera de tillvägagångssätt vi funnit. De faktorer som åsyftas är snarare antal besökare, portalens intäkter och kostnader än makroekonomiska faktorer som ränteläget. Antalet besökare på en portal, portalens utbud av tjänster och målgruppens utseende är de faktorer som mest påverkar hur höga intäkter en portal kan få och som sin tur påverkar portalens värde. Fallföretaget skulle, med utgångspunkt i dessa faktorer, kunna värdras till mellan antingen -1,9 miljoner eller till 35 miljoner beroende på vilket tillvägagångssätt och vilket tidsperspektiv man använder.</p>
357

Informationshantering i webbportalsystem

Apelqvist, Helén, Ekberg, Linda, Gustafson, Yvonne January 2003 (has links)
No description available.
358

Värdering av Internetportaler : en studie av värdebyggande faktorer vid värdering av portaler

Lundevall, Jenny, Åström, Maria January 2000 (has links)
Många Internetrelaterade företag har den senaste tiden på börser runt om i världen värderats till flera miljarder kronor. Internetföretag utan vinst eller historia är svåra att värdera med traditionella värderingsmetoder och därför krävs andra tillvägagångssätt för värdering. Syftet är att beskriva vilka faktorer som påverkar värderingen av Internetportaler samt att med hjälp av dessa faktorer försöka värdera en portal. Undersökningen är dels teoretisk och behandlar avsaknaden av fungerande modeller för portal-värdering, dels rör problemet vårt fallföretag, på vilket vi försöker applicera de tillvägagångssätt vi funnit. De faktorer som åsyftas är snarare antal besökare, portalens intäkter och kostnader än makroekonomiska faktorer som ränteläget. Antalet besökare på en portal, portalens utbud av tjänster och målgruppens utseende är de faktorer som mest påverkar hur höga intäkter en portal kan få och som sin tur påverkar portalens värde. Fallföretaget skulle, med utgångspunkt i dessa faktorer, kunna värdras till mellan antingen -1,9 miljoner eller till 35 miljoner beroende på vilket tillvägagångssätt och vilket tidsperspektiv man använder.
359

New Efficient Detector for Radiation Therapy Imaging using Gas Electron Multipliers

Östling, Janina January 2006 (has links)
Currently film is being replaced by electronic detectors for portal imaging in radiation therapy. This development offers obvious advantages such as on-line quality assurance and digital images that can easily be accessed, processed and communicated. In spite of the improvements, the image quality has not been significantly enhanced, partly since the quantum efficiency compared to film is essentially the same, and the new electronic devices also suffer from sensitivity to the harsh radiation environment. In this thesis we propose a third generation electronic portal imaging device with increased quantum efficiency and potentially higher image quality. Due to the parallel readout capability it is much faster than current devices, providing at least 200 frames per second (fps), and would even allow for a quality assurance and adaptive actions after each accelerator pulse. The new detector is also sensitive over a broader range of energies (10 keV - 50 MeV) and can be used to obtain diagnostic images immediately prior to the treatment without repositioning the patient. The imaging could be in the form of portal imaging or computed tomography. The new detector is based on a sandwich design containing several layers of Gas Electron Multipliers (GEMs) in combination with, or integrated with, perforated converter plates. The charge created by the ionizing radiation is drifted to the bottom of the assembly where a tailored readout system collects and digitizes the charge. The new readout system is further designed in such a way that no sensitive electronics is placed in the radiation beam and the detector is expected to be radiation resistant since it consists mainly of kapton, copper and gas. A single GEM detector was responding linearly when tested with a 50 MV photon beam at a fluence rate of ~1010 photons mm-2 s-1 during 3-5 μs long pulses, but also with x-ray energies of 10-50 keV at a fluence rate of up to ~108 photons mm-2 s-1. The electron transmission of a 100 μm thick Cu plate with an optical transparency of ~46% was found to be ~15.4%, i.e. the effective hole transmission for the electrons was about one third of the hole area. A low effective GEM gain is enough to compensate for the losses in converters of this dimension. A prototype for the dedicated electronic readout system was designed with 50 x 100 pixels at a pitch of 1.27 mm x 1.27 mm. X-ray images were achieved with a single GEM layer and also in a double GEM setup with a converter plate interleaved. To verify the readout speed a Newton pendulum was imaged at a frame rate of 70 fps and alpha particles were imaged in 188 fps. The experimental studies indicates that the existing prototype can be developed as a competitive alternative for imaging in radiation therapy.
360

The Influence of Portal Vein Occlusion on Liver Mitochondria in Rats after Releasing Biliary Obstruction

IWASE, MASANORI 03 1900 (has links)
No description available.

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