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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.
21

網際網路資料庫選擇模式之研究 / Internet Database Management and Systems Selection Study

謝麗芬, Hsieh, Li-Fen Unknown Date (has links)
最近幾年來,網際網路的出現及應用面的廣泛,改變了企業的資訊架構。從Client/Server擴展到以Web為應用程式的平台,企業面臨了資訊架構的重整,企業網路、電子商務都是現今最新的應用。由於全球資訊網採開放架構,並以HTML、HTTP為標準,使得資訊業者有所依循,開發出許多產品來滿足企業的需求。隨著Web的廣泛使用,應用程式架構、介面與行為特質都將與以往有著大大的不同,元件及交易導向的Web應用程式是勢在必行的路。 對此變革,企業最重要的課題之一是,如何建構完整的企業網路環境以增強競爭力。資料庫系統是企業各種資訊軟體的基礎,在以Web為應用程式的平台的架構下,它仍是其中重要的關鍵元件。選擇資料庫系統必須考慮許多因素,而且現有的資料庫系統的產品很多,各項產品的特性與優點均有不同,每一種產品甚至可再細分成許多元件,可依照需要選用,因此資料庫產品的選擇變成一種複雜的過程。若選擇錯誤則不僅是金錢耗費的損失,更深遠地影響整個企業的順利運作,甚至是企業競爭力的下降,更可能嚴重到影響企業的存續。故資料庫系統的選擇不可不慎。 本文提出一網際網路資料庫體系選擇模式,協助企業在全球資訊網的開放架構及多階層應用系統環境下,評選出符合企業本身狀況及需求的網際網路資料庫系統。此模式內容包含,需求分析與確認、第一至四級網際網路資料庫體系需求屬性之彙整、兩階段的廠商篩選及含加權機制之廠商評比。 最後並將此模式運用於,行政院衛生署藥物食品檢驗局之購置網際網路資料庫設備計劃。 / Internet technology has drastically changed the enterprise computing and platform. Database management and systems represent the core of the change and the key of the new revolution of the information technology and infrastructure. Business information and models have been stored and manipulated through the use of the database technology. Due to the fast growing speed and variety of the database products in the marketplace, managers are having difficult making the right decision in selecting and maintaining the Internet database management and systems. To tackle this issue, we propose a requirements-based software selection model from the user’s viewpoint. In this research, we develop a five-step choice model with an emphasis on the requirement analysis and rank analysis. We collect and compile the functional and non-functional characteristics and features of the Internet database management and systems. We classify and organize them into a four-layer hierarchy and work with the weight mechanism in the rank analysis. This choice model adopts another five-part rank policy in order to produce the final suggestion of software selection. In the end, we apply the new model in a field case study of the Web Database Systems Procurement Project with the National Laboratories of Foods and Drugs, Department of Health, Executive Yuan.
22

Mobile Velocity Estimation Using a Time-Frequency Approach

Azemi, Ghasem January 2003 (has links)
This thesis deals with the problem of estimating the velocity of a mobile station (MS)in a mobile communication system using the instantaneous frequency (IF) of the received signal at the MS antenna. This estimate is essential for satisfactory handover performance, effective dynamic channel assignment, and optimisation of adaptive multiple access wireless receivers. Conventional methods for estimating the MS velocity are based either on the statistics of the envelope or quadrature components of the received signal. In chapter 4 of the thesis, we show that their performance deteriorates in the presence of shadowing. Other velocity estimators have also been proposed which require prior estimation of the channel or the average received power. These are generally difficult to obtain due to the non-stationary nature of the received signal. An appropriate window which depends on the unknown MS velocity must first be applied in order to accurately estimate the required quantities. Using the statistics of the IF of the received signal at the MS antenna given in chapter 3, new velocity estimators are proposed in chapter 4 of this thesis. The proposed estimators are based on the moments, zero-crossing rate, and covariance of the received IF. Since the IF of the received signal is not affected by any amplitude distortion, the proposed IF-based estimators are robust to shadowing and propagation path-loss. The estimators for the MS velocity in a macro- and micro-cellular system are presented separately. A macro-cell system can be considered as a special case of a micro-cell in which there is no line-of-sight component at the receiver antenna. It follows that those estimators which are derived for micro-cells can be used in a macro-cell as well. In chapter 4, we analyse the performance of the proposed velocity estimators in the presence of additive noise, non-isotropic scattering, and shadowing. We also prove analytically that the proposed velocity estimators outperform the existing methods in the presence of shadowing and additive noise. The proposed IF-based estimators need prior estimation of both the IF of the received signal and Ricean K-factor. The IF estimation in a typical wireless environment, can be considered as a special case of a general problem of IF estimation in the presence of multiplicative and additive noise. In chapter 5, we show that current time-frequency approaches to this problem which are based on the peak of a time-frequency distribution (TFD) of the signal, fail because of the special shape of the power spectral density of the multiplicative noise in a wireless environment. To overcome this drawback, the use of the first-order moment of a TFD is studied in chapter 5. Theoretical analysis and simulations show that the IF estimator based on the first-order moment of a TFD exhibits negligible bias when the signal-to-additive noise ratio is more than 10 dB. The Ricean K-factor is not only necessary for velocity estimation in micro-cells, but also is a measure of the severity of fading and a good indicator of the channel quality. Two new methods for estimating the Ricean K-factor based on the first two moments of the envelope of the received signal, are proposed in chapter 6. Performance analysis presented in chapter 6, prove that the proposed K estimators are robust to non-isotropic scattering. Theoretical analysis and simulations which are presented in chapters 4 and 7 of this thesis, prove that the proposed velocity and K estimators outperform existing estimators in the presence of shadowing and additive noise.
23

High-Performance Persistent Identification for Research Data Management

Berber, Fatih 07 September 2018 (has links)
No description available.
24

Multi-Tier Systems of Support and Their Impact on a Title I School

Parsons, Valerie L. 08 1900 (has links)
The purpose of this study was to examine a novel campus-based multi-tier systems of support (MTSS) framework. The framework included a standard-response protocol approach to response to intervention (RTI), integrated with a reversed process to professional learning communities, to support learning for students who were struggling to learn. Using a causal-comparative research design, a secondary analysis of quantitative data from one Title I school of approximately 500 students during the 2016-2018 school years was conducted to determine the level of impact MTSS had on reading achievement. Independent and paired samples t-tests were used to analyze iStation indicators of progress reading scores, resulting in statistically significant results. Kindergarten through 5th grade students' reading scores were significantly higher after one year of MTSS intervention than students who did not receive MTSS. One year of MTSS intervention had a statistically significant impact on both early and intermediate readers. Early readers, who began below grade level, performed significantly higher in reading achievement after just one year of MTSS as well. Intermediate readers, who began on or above grade level did not perform significantly higher in reading achievement after one year of MTSS, however. Possible long-term implications for MTSS were analyzed by comparing one year to two years of MTSS intervention. A consistently significant increase in reading scores occurred, suggesting growth that took place from one year of MTSS was enhanced by an additional year of MTSS. This novel MTSS framework could be used by campus leaders as an intervention to provide equitable learning for all students and yield statistically significant results in reading achievement in one school year. Additional research examining the impact of MTSS on Tier 1 intermediate readers receiving enrichment is recommended.
25

Rozšiřitelný informační systém sdružení SDC s vícevrstvou architekturou / Extendable Information System of SDC with a Multi-Tier Architecture

Vrážel, Dušan Unknown Date (has links)
This master's thesis deals with analysis, design and implementation of an information system that allows easy extensibility with three-tier architecture.   System is developed using object oriented approach by programming language PHP, relational database server MySQL and web services and protocol SOAP. The View tier is implemented by web technologies XHTML and CSS. Analysis and design of this system is done with using the modeling language UML.     In this thesis is described the problem of multi-tier software architecture, theory of development information's systems and described design and implementation of an information system with a three-tier architecture and it's application in the society SDC.

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