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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.
261

CPIM, an Improved Element Free method for Engineering Application

Liu, Chang-jung 13 January 2006 (has links)
Abstract To improve the application of Point Interpolation Method (PIM) in Element Free Galerkin Method (EFG) is the aim of this study. The trait of EFG is using overlap of influence domain between different nodes to construct discretization nodes¡¦ connection. EFG just uses nodal data, but not element. For constructing shape function, EFG has two types of methods, Fitting and Interpolation. Fitting uses Moving Least Square Method (MLS). MLS-EFG has stable effect on numerical analysis; however, users who use it need to choose more numerical parameters and do more computation. Besides, users can not apply boundary conditions directly when using MLS-EFG. Interpolation method applies nodal coordinates to proceed computation, and it called PIM. Boundary conditions could be used directly and less computation is needs while using PIM. However, the coefficient of interpolation function of sample is singular. This study tries to construct Coordination Point Interpolation Method. It owns advantages of both methods that mentioned above, and extra numerical parameters are not needed. It applies the notion of influence domain of MLS-EFG, then search correlative efficient nodes which are contained in near field of sample. The correlative efficient nodes make up matrix that con cause inverse matrix. In addition, via numerical simulations, it shows that CPIM has excellent convergence and accurate solution, and is better that MLS-EFG.
262

An Adjustable Expanded Index for Predictive Queries of Moving Objects

Chang, Fang-Ming 13 July 2007 (has links)
With the development of wireless communications and mobile computing technologies, the applications of moving objects have been developed in many topics, for example, traffic monitoring, mobile E-Commerce, Navigation System, and Geographic Information System. The feature of the moving objects is that objects change their locations continuously. Conventional spatial databases can not support to store the moving objects efficiently, because the databases must be updated frequently. Therefore, it is important to index moving objects for efficiently answering queries about moving objects. Among the spatial indexing methods for predicting current and future data, the approach of parametric spatial access methods has been applied largely, since it needs little memory space to preserve parametric rectangles, and it still provides good performance, so it is adopted generally. The methods of this approach include the TPR-tree, the TPR*-tree, the Bx-tree, and the Bxr-tree. Among those methods, the Bxr-tree improves CPU performance of TPR-tree by expanding query region first, and improves I/O performance of the Bxr-tree by expanding the data blocks additionally. However, the query process of the B$^x_r$-tree is too rough such that it costs too much CPU and I/O time to check the useless data. Therefore, in this thesis, we propose a new data structure and a new query processing method named Adjustable Expanded Index (AEI), to improve the disadvantages of the Bxr-tree. In our method, we let each block records the maximum and minimum speeds of each of eight directions, instead of only the maximum speed of each of four directions in the Bxr-tree method. Based on the data structure, the query region can be expanded in each of eight directions individually, instead of being expanded in each of four directions once in the Bxr-tree method. Moreover, in our AEI method, the data blocks can be expanded according to the direction toward the query region, instead of being expanded in four directions in the Bxr-tree method. In this way, the query process of AEI checks less number of data blocks because it considers the minimum speed of each of eight directions. Furthermore, the objects are divided into four groups in AEI according to their directions, while the Bxr-tree method does not. Only the objects moving to query region will be checked in the query process of AEI. Therefore, we can reduce more number of retrieved data blocks and the number of I/O operations in our method than the Bxr-tree. From our simulation, we show that the query process of the AEI method is more efficient than that of the Bxr-tree in term of the average numbers of retrieved data blocks and I/O operations.
263

Monitoring High Quality Processes: A Study Of Estimation Errors On The Time-between-events Exponentially Weighted Moving Average Schemes

Ozsan, Guney 01 September 2008 (has links) (PDF)
In some production environments the defect rates are considerably low such that measurement of fraction of nonconforming items reaches parts per million level. In such environments, monitoring the number of conforming items between consecutive nonconforming items, namely the time between events (TBE) is often suggested. However, in the design of control charts for TBE monitoring a common practice is the assumptions of known process parameters. Nevertheless, in many applications the true values of the process parameters are not known. Their estimates should be determined from a sample obtained from the process at a time when it is expected to operate in a state of statistical control. Additional variability introduced through sampling may significantly effect the performance of a control chart. In this study, the effect of parameter estimation on the performance of Time Between Events Exponentially Weighted Moving Average (TBE EWMA) schemes is examined. Conditional performance is evaluated to show the effect of estimation. Marginal performance is analyzed in order to make recommendations on sample size requirements. Markov chain approach is used for evaluating the results.
264

A Empirical Study on Stock Market Timing with Technical Trading rules

Chao, Yung-Yu 10 July 2002 (has links)
In the last few years, it has been proved that the movements of financial asset have the property of non-linearity and show some tendency within a given period. Increasing evidence that technical trading rules can detect non-linearity in financial time series has renewed interest in technical analysis. This study evaluates the market timing ability of the moving average trading rules in twelve equity markets in the developed markets and the emerging markets from January 1990 through Match 2002. We use traditional test, bootstrap p-value test, Cumby-Modest¡¦s market timing ability test and simulation stock trade to evaluate market timing ability. The overall results indicate that the moving average trading rules have predictive ability with respect to market indices in the Asia emerging stock markets. These findings may provide investors with important asset allocation information.
265

Mining IT Product Life Cycle from Massive Newsgroup Articles

Chou, Cheng-Chi 22 July 2003 (has links)
Product life cycle (PLC) may be used as a managerial tool. Marketing strategies must change as the product goes through its life cycle. If managers understand the cycle concept, they are in a better position to forecast the future sales activities and plan marketing strategies. However, people often make the wrong PLC because of the difficulty of data access and lacking decision-making information. Therefore, this thesis applies customer behavior model to analyze the relationship between the frequency and the duration time from the product discussion, and it calculates the PLC pattern to explore the product¡¦s current position in customers¡¦ mind. Finally, the PLC curve will be constructed by using the information that we got from previous analysis. Moreover, we also employ data mining and information retrieval technique to diagnose the variance of discussion frequency and the content of discussion article to extract the distinctive event that influenced PLC curve. The main contributions of this thesis are described as the following sentence:
266

由國營企業轉成民營企業:由中華電信經驗對ONATAL之參考價值

Mamadou Unknown Date (has links)
Around the world, countries are moving towards a market economy in order to integrate the global marketplace. Telecommunications are among the industries concerned the most in this trend, as governments are significantly reducing their involvement in this industry through liberalization and/or partial or complete privatization of their national telecommunications corporations. For Burkina Faso it is no different, as ONATEL, the national telecommunications company in Burkina Faso, has been caught in this trend. Since December 1998, the government of Burkina Faso initiated a reform of its telecommunications sector with the overall goal to achieve the liberalization of telecommunications services, and accomplish a mixed ownership of ONATEL. The objective of this study is to review the ongoing privatization of ONATEL based on an analysis of general practices regarding economic reforms applied elsewhere, and then make recommendations for both the government of Burkina Faso and ONATEL, for a successful implementation of the process and the national telecommunication policies. We accomplish this objective through four research questions. The first one correlates privatization and economic development with the aim to see how the divesture of ONATEL can foster the telecommunications development in Burkina Faso. The second one emphasizes the government chosen strategy to privatize ONATEL, allowing for a review of alternative privatization methods and the rationale behind the government’s option. The third research questions deals with ONATEL’s strategies to sustain its development amongst an environment of increased competition. This question facilitates an assessment of the firm’s preparation for competition and allows for the formulation of some recommendations in such regard. The last research question touches on the privatization process of Chunghwa Telecom, the once, state-owned Telecommunications Company in Taiwan. This final aspect of the research helps to extract effective lessons that can be applicable for the government of Burkina Faso and ONATEL, by analyzing and understanding the privatization experience in Chunghwa Telecom’s methods and formulations of business strategies, for their own privatization.
267

Moving-Average approximations of random epsilon-correlated processes

Kandler, Anne, Richter, Matthias, vom Scheidt, Jürgen, Starkloff, Hans-Jörg, Wunderlich, Ralf 31 August 2004 (has links) (PDF)
The paper considers approximations of time-continuous epsilon-correlated random processes by interpolation of time-discrete Moving-Average processes. These approximations are helpful for Monte-Carlo simulations of the response of systems containing random parameters described by epsilon-correlated processes. The paper focuses on the approximation of stationary epsilon-correlated processes with a prescribed correlation function. Numerical results are presented.
268

Lösung parabolischer Differentialgleichungen mit zufälligen Randbedingungen mittels FEM

Kandler, Anne, vom Scheidt, Jürgen, Unger, Roman 31 August 2004 (has links) (PDF)
In dieser Arbeit werden stochastische Charakteristiken der Lösung parabolischer Differentialgleichungen mit zufälligen Neumann-Randbedingungen mit Hilfe der Finite-Elemente-Methode angegeben. Dabei wird der Berechnung der Korrelations- bzw. Varianzfunktion besondere Bedeutung beigemessen. Das stochastische Randanfangswertproblem wird durch Anwendung von FEM-Techniken durch ein System gewöhnlicher Differentialgleichungen mit stochastischen inhomogenen Termen approximiert. Die Modellierung der stochastischen Eingangsparameter durch epsilon-korrelierte Felder gestattet Entwicklungen der Lösungscharakteristiken nach der Korrelationslänge. Numerische Beispiele enthalten den Vergleich zwischen analytischen Ergebnissen und Simulationsresultaten.
269

Higher eyes in the sky the feasibility of moving AWACS and JSTARS functions into space /

Corcoran, Kimberly M. January 1900 (has links)
Thesis--School of Advanced Airpower Studies, Maxwell Air Force Base, Ala., 1997-98. / Title from title screen (viewed Oct. 10, 2003). "October 1999." Includes bibliographical references.
270

Cinema park /

Kung, Sze-chung, Charles. January 1997 (has links)
Thesis (M. Arch.)--University of Hong Kong, 1997. / Includes special report study entitled :Integration of architecture and ground form. Includes bibliographical references.

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