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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.
161

Discovering Issue Networks Using Data Mining Techniques

Chuang, Tse-sheng 01 August 2002 (has links)
By means of data mining techniques development these days, the knowledge discovered by virtue of data mining has ranging from business application to fraud detection. However, too often, we see only the profit-making justification for investing in data mining while losing sight of the fact that they can help resolve issues of global or national importance. In this research, we propose the architecture for issue oriented information construction and knowledge discovery that related to political or public policy issues. In this architecture, we adopt issue networks as the description model and data mining as the core technique. This study is also performed and verified with prototype system constructing and case data analyzing. There are three main topics in our research. The issue networks information construction starts with text files information retrieving of specified issue from news reports. Keywords retrieved from news reports are converted into structuralized network nodes and presented in the form of issue networks. The second topic is the clustering of network actors. We adopt an issue-association clustering method to provide views of clustering of issue participators based on relations of issues. In third topic, we use specified link analysis method to compute the importance of actors and sub-issues. Our study concludes with performance evaluation via domain experts. We conduct recall, precision evaluation for first topic above and certainty, novelty, utility evaluation for others.
162

Development of IEEE 802.11b RF Transceiver Modules

Han, Fu-Yi 10 July 2003 (has links)
This thesis consisted of three parts. Part 1 introduced the design procedure of an RF transceiver modules for IEEE 802.11b WLAN system. It contained the selection of RF architectures, frequency planning, and the receiver link budget analysis flow. Part 2 focused on the implementation of each stage in the whole RF link. The design considerations of choosing passive elements and the parasitic effect of the evaluation board are discussed. Part 3 integrated the whole RF transceiver module and estimated the performance of this module through the link budget analysis method. Furthermore, a complete specification measurement was accomplished by using the standard test signals. The test results confirmed with the budget results, and also pass the specification of IEEE 802.11b WLAN system.
163

Connection of modular steel beam precast slab units with cast-in-place closure pour slabs

Brush, Natalie Camille 17 February 2005 (has links)
Jointless bridges are advantageous in removing mechanical joints which are a known cause of bridge deterioration. Elimination of joints provides a smoother riding surface and removes the possibility of de-icing salts penetrating the deck and corroding the deck reinforcing and underlying bridge superstructure. Jointless bridges are traditionally constructed by monolithically casting the entire bridge deck on beams after they have been erected. However, this process requires extensive in-field formwork and lengthy traffic closures. The Texas Department of Transportation proposes a new method of constructing jointless bridges using prefabricated girder-and-deck units connected on-site with cast-in-place closure pours. This new system will expedite construction and reduce disturbances to the traveling public. The objective of this experimental study was to investigate the behavior of the cast-in-place closure pour slab and to determine if it responds to wheel loads in the same way as a traditional monolithic continuous deck. The effects of the cold joints and discontinuous steel details are the focus of the research work.
164

Design, implementation, and measurements of a high speed serial link equalizer

Evans, Andrew John 23 April 2013 (has links)
The advancements of semiconductor processing technology have led to the ability for computing platforms to operate on large amounts of data at very high clock speeds. To fully utilize this processing power the components must have data continually available for operation upon and transport to other system components. To enable this data requirement, high speed serial links have replaced slower parallel communication protocols. Serial interfaces inherently require fewer signals for communication and thus reduce the device pin count, area and cost. A serial communication interface can also be run at a higher frequency because the clock skew between channels is no longer an issue since the data transmitted on various channels is independent. Serial data transmission also comes with a set of drawbacks when signal integrity is considered. The data must propagate through a channel that induces unwanted effects onto the signals such as intersymbol interference. These channel effects must be understood and mitigated to successfully transmit data without creating bit errors upon reception at the target component. Previously developed adaptive equalization techniques have been used to filter the effects of intersymbol interference from the transmitted data in the signal. This report explores the modeling and implementation of a system comprised of a transmitter, channel, and receiver to understand how intersymbol interference can be removed through a decision-feedback equalizer realized in hardware. The equalizer design, implementation, and measurements are the main focus of this report and are based on previous works in the areas of integrated circuit testing, channel modeling, and equalizer design. Simulation results from a system modeled in Simulink are compared against the results from a hardware model implemented with an FPGA, analog to digital converter and discrete circuit elements. In both the software and hardware models, bit errors were eliminated for certain amounts of intersymbol interference when a receiver with decision-feedback equalization was used instead of a receiver without equalization. / text
165

Implementing Real-time Provisioning for Space Link Extension (SLE) Service Instances

Lokshin, Kirill, Puri, Amit, Irvin, Dana, Ross, Frank, Rush, Rebecca 10 1900 (has links)
ITC/USA 2012 Conference Proceedings / The Forty-Eighth Annual International Telemetering Conference and Technical Exhibition / October 22-25, 2012 / Town and Country Resort & Convention Center, San Diego, California / Space Link Extension (SLE) is a set of recommended standards for mission cross support developed by the Consultative Committee for Space Data Systems (CCSDS). The SLE recommendations define protocols for extending the space link from ground terminals to other facilities deeper within a ground network, allowing distributed access to space link telecommand and telemetry services. The SLE protocols are widely used to provide cross support between sites, programs, and agencies. In traditional SLE deployments, individual service instances have been manually provisioned well in advance of the commencement of cross support for a particular mission, and hardware and software resources have been allocated to those service instances at the time of provisioning. While valid, this approach requires that dedicated resources be provided for each mission and service instance, and limits an SLE provider's ability to reallocate resources in real time based on system availability or other factors. This paper discusses an alternative approach to SLE service provisioning, in which individual service instances are assigned resources from a common resource pool at the time that each service instance is initialized. The paper addresses the key design elements and technical tradeoffs involved in this approach, and discusses the potential benefits with regard to load balancing, equipment reuse, and resiliency against system failure.
166

Implementing Space Link Extension (SLE) for Very High Rate Space Links

Lokshin, Kirill, Puri, Amit, Irvin, Dana, Ross, Frank, Rush, Rebecca 10 1900 (has links)
ITC/USA 2012 Conference Proceedings / The Forty-Eighth Annual International Telemetering Conference and Technical Exhibition / October 22-25, 2012 / Town and Country Resort & Convention Center, San Diego, California / Space Link Extension (SLE) is a set of recommended standards for mission cross support developed by the Consultative Committee for Space Data Systems (CCSDS). The SLE recommendations define protocols for extending the space link from ground terminals to other facilities deeper within a ground network, allowing distributed access to space link telecommand and telemetry services. The SLE protocols are widely used to provide cross support between sites, programs, and agencies. Traditional SLE protocol implementations have been limited in their ability to support high data rates and large numbers of concurrent service instances. Such limited solutions were sufficient to support the needs of spacecraft health and status or older, low-rate science data. More recent missions, however, have required significantly increased data rates on both uplink and downlink paths, necessitating a new approach to SLE implementation. This paper discusses the design principles involved in implementing the SLE protocols in support of high channel and aggregate mission data rates, with particular focus on the tradeoffs necessary to provide SLE link capability at sustained single-channel rates above 1 Gigabit per second. The paper addresses significant performance bottlenecks in the conventional SLE protocol stack and proposes potential mitigation strategies for them.
167

How to Assess Risks in Weak Links in Cold Chain Distribution Process?

Lu, Shuchang, Gu, Yufan, Predko, Radzion January 2015 (has links)
Abstract Title: How to assess risks in weak links in cold chain distribution process? Authors: Shuchang Lu, Yufan Gu & Radzion Predko Tutor: Åsa Gustafsson Examiner: Dr. Lars-Olof Rask Course: 4FE06E - Master Thesis Research Questions: • Why do cold chain products have quality risk? -  What kind of weak links exist in distribution process of cold chain? -  What kind of risks exist in weak links of distribution process of cold chain? -  How to assess risks in weak links of distribution process of cold chain? Background: The increasing food wastes and starving people have made food preserved by cold chain as a significant and profitable issue. An effective and efficiency cold chain can make a big difference in the whole food supply chain around the world. With the improvements of modern technologies, cold chain distribution is experiencing changes. Purpose: To identify weak links in distribution channel of cold chain products. What kind of risks exist in these weak inks and how to assess them. Method: Positivistic is used throughout the paper. Multiple exploratory case study is our way of research our problems. Data were gathered from interview, documents and company’s website. Conclusions: Human handling in delivery process, the way retailers deal with frozen products, how do different participants manage their resources and safety of product and its quality are main reasons for quality risk. Risks in weak links can cause product quality problem in cold chain distribution channel. Therefore, assess these risks can help managers to deal with them. Keywords: Cold chain distribution, quality problem, weak link, risk
168

Symmetric Spaces and Knot Invariants from Gauge Theory

Daemi, Aliakbar January 2014 (has links)
In this thesis, we set up a framework to define knot invariants for each choice of a symmetric space. In order to address this task, we start by defining appropriate notions of singular bundles and singular connections for a given symmetric space. We can associate a moduli space to any singular bundle defined over a compact 4-manifold with possibly non-empty boundary. We study these moduli spaces and show that they enjoy nice properties. For example, in the case of the symmetric space SU(n)/SO(n) the moduli space can be perturbed to an orientable manifold. Although this manifold is not necessarily compact, we introduce a comapctification of it. We then use this moduli space for singular bundles defined over 4-manifolds of the form YxR to define knot invariants. In another direction we mimic the construction of Donaldson invariants to define polynomial invariants for closed 4-manifolds equipped with smooth action of Z/2Z. / Mathematics
169

Impact of Macrobend Loss on the Bandwidth of Standard and Bend-Optimized Multimode Fibers

Li, Ying January 2009 (has links)
10 Gigabit Ethernet (GbE) demands faster optical sources to support high modulation rates. At the same time, the allowable margin in the 10 GbE link power budget is decreasing. This means that a 10 GbE system is unable to support as many tight bends, and it is more difficult to avoid the costly downtime that results when the allowable margin is exceeded. The recent introduction of bend-optimized (BO) multimode fiber (MMF) provides a clear solution. 850 nm vertical cavity surface emitting lasers (VCSELs) and MMFs have long been the most cost effective choice for short reach premise applications. As will be shown, the combination of BO-MMF with VCSELs is even more attractive.Historically, MMF systems operating at low bit rates of 10-100 Mbps used light-emitting diodes (LED) sources, which launch nearly equal power into every fibermode. This launch is approximated by the overfilled launch (OFL), which is still used to characterize the core diameter and numerical aperture of MMF. Unlike LEDs, VCSELs typically underfill the fiber core and are better represented by an encircled flux launch (EFL). Using OFL to evaluate a VCSEL-based MMF system could therefore produce inaccurate and misleading results. A recent study [1] characterized the macrobend loss of MMF with overfilled and restricted mode offset launch conditions. In this study, the MMFs performance with an EFL is evaluated, which is a more relevant launch condition for laser transmission. The impact of both launch conditions, OFL and EFL, on MMF performance is studied and compared.We characterize macrobend losses at small bend radii and their impact on thebandwidth for both standard 50/125 um MMF and a newly introduced BO-MMF.In addition, the 10 GbE link performance is also evaluated using the IEEE link model P802.3ae3.The simulation results illustrate that both macrobend loss and bandwidth are vital to the overall optical link performance. The 10 GbE link performance of the standard fiber deteriorates with macrobends, while the bend-optimized fiber is insensitive to the deployment conditions.
170

The dramatic growth of open access : implications and opportunities for resource sharing

Morrison, Heather 08 1900 (has links)
The Open Access movement seeks to make scholarly, peer-reviewed journal articles freely available to anyone, anywhere over the World Wide Web. There were some very significant developments in the area of Open Access (OA) in 2004, including statements by major funders in support of Open Access. There are now so many Open Access scholarly journal articles freely available, that, in the author’s opinion, being aware of, and using, the resources and related tools is now essential for libraries. Libraries can provide more resources faster for users by supplementing paid resources with ones that are Open Access. Library resources, such as link resolvers, are beginning to incorporate Open Access materials and web searches for Open Access materials. For example, the reSearcher software suite includes Open Access collections along with subscription-based resources in the CUFTS journals knowledgebase, and a web search for an Open Access copy of an article in the GODOT link resolver. SFX also incorporates Open Access journals. After exhausting more traditional resources, interlibrary loans staff are beginning to include Google searching in their workflow. This article will discuss what Open Access is, the dramatic growth of Open Access, and major collections, resources and tools. Implications, issues, and leadership opportunities for resource sharing specialists will be explored.

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