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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.
1

Numerical Computation of Water Tranquility in a Harbor

Chen, San-xue 26 February 2004 (has links)
Harbor construction is the most important basic development in fishery. To sustain harbor tranquility and prevent entrance from siltation are essential for maintaining normal operations of a harbor. Although the number of fishing harbors in Taiwan is said to be as many as the car parks on the land, there are numerous reports of poor tranquility that required urgent public attention. Supported by recent development in science and technology, research advances in numerical modeling have produced accurate results from a range of numerical schemes. Comparing to the conventional hydraulic models that require long executive time and large budget, numerical modeling on computer is a most effective alternative. In this study, the wave analysis system¡ÐCATWAVES developed by Professor Shigeaki Tsutsui at University of the Ryukyu in Okinawa, Japan is adopted to simulate the wave motions around a fishing harbor, in order to evaluate the tranquility of a harbor basin. CATWAVES calculates the transformation of surface gravity waves in the ocean using a mild-sloped equation of elliptic type. A finite-element scheme is used effectively to handle arbitrary bottom bathymetry and irregular boundary. This report first provides an outlines of the CATWAVES system, followed by verification of wave height distribution for two classic cases, being waves passing a semi-infinite breakwater in constant depth and waves propagating over a submerged circular shoal on a sloping beach, respectively. The CATWAVES system is then applied to assess the harbor tranquility at two prototype fishing harbors in Taiwan. The first case is to verify the results of several improvement options tested in hydraulic models elsewhere to improve the tranquility at Badoutz, a class one fishing harbor in northeastern Taiwan. The second case is to provide a better alternative plan of breakwater extension at Mito, a class three harbor in the southwestern part of Taiwan, where excessive wave heights have been experienced by local fishermen. It is believed that Tsutsui¡¦s CATWAVES system has made a great breakthrough in handling irregular bottom bathymetry and arbitrary outline of harbor plan. From the two prototype cases examined in this study, this system is found to be highly adaptive for calculating wave motions around any fishing harbor in Taiwan.
2

Solid waste management implementation, an opportunity not to be wasted : Solid waste management in Babati, Tanzania

Jaensson, Stina January 2008 (has links)
<p>The amount of waste is increasing in the world due to changed consumption patterns and increasing populations. This is a problem especially in poor countries where the ability to handle the waste is limited due to financial and management problems. The non-profit organization WASTE has developed an Integrated Sustainable Waste Management- concept (ISWM), trying to help cities with waste management. The concept focuses on cooperation and participation among stakeholders, and also introduction of micro-and small enterprises and community based organizations. The aim of this thesis is to give recommendations to Babati, a small town in the north of Tanzania, how to develop their waste management based on the concept of ISWM. A case study has been carried out in the town, founding out that the streets of the town is free from litter today but is  facing big challenges in the future. The town has a growing population and is just about to change waste management system. The new system is not developed in cooperation with the stakeholders in the town, but rather an initiative from the authorities, which will make the system very fragile. However, it is not too late to take action for securing a successful implementation of the system. The authorities of Babati now have an opportunity to adjust the solid waste system before population and the mountain of waste gets out of control. The suggestions given to Babati are to have parallel systems of waste collecting; it will try to meet people’s different needs. Encourage people to make waste handling into a business is also essential, that will reduce the amount of waste and generate incomes at the same time. Finally and most important is to involve all stakeholders and listen to their needs.  If the stakeholders are parts of the process and involved in decision making, it is much more likely that the system becomes sustainable and a success.</p>
3

Solid waste management implementation, an opportunity not to be wasted : Solid waste management in Babati, Tanzania

Jaensson, Stina January 2008 (has links)
The amount of waste is increasing in the world due to changed consumption patterns and increasing populations. This is a problem especially in poor countries where the ability to handle the waste is limited due to financial and management problems. The non-profit organization WASTE has developed an Integrated Sustainable Waste Management- concept (ISWM), trying to help cities with waste management. The concept focuses on cooperation and participation among stakeholders, and also introduction of micro-and small enterprises and community based organizations. The aim of this thesis is to give recommendations to Babati, a small town in the north of Tanzania, how to develop their waste management based on the concept of ISWM. A case study has been carried out in the town, founding out that the streets of the town is free from litter today but is  facing big challenges in the future. The town has a growing population and is just about to change waste management system. The new system is not developed in cooperation with the stakeholders in the town, but rather an initiative from the authorities, which will make the system very fragile. However, it is not too late to take action for securing a successful implementation of the system. The authorities of Babati now have an opportunity to adjust the solid waste system before population and the mountain of waste gets out of control. The suggestions given to Babati are to have parallel systems of waste collecting; it will try to meet people’s different needs. Encourage people to make waste handling into a business is also essential, that will reduce the amount of waste and generate incomes at the same time. Finally and most important is to involve all stakeholders and listen to their needs.  If the stakeholders are parts of the process and involved in decision making, it is much more likely that the system becomes sustainable and a success.
4

Corporate Strategies During an Economic Crisis : Cases of Micro and Small Italian Ceramic Enterprises

Campagnaro, Gabriele January 2015 (has links)
Extensive research has previously been conducted in the field of corporate strategies during economic crisis, analyzing different contexts and countries. Nevertheless, the main focus has always been on small and medium enterprises without considering the importance that micro enterprises have in the European business tradition. The research gap for this study has been identified concerning Italian micro and small enterprises which, despite the importance of these kinds of companies in the national scenario, have not been considered yet. A literature review on this area highlighted the status of the research within the field, identifying the research gap and the purpose of this dissertation. The purpose is to contribute the research by understanding which is the relationship between strategies and performance with special attention on micro and small enterprises, aiming to formulate a guideline that may be followed by other enterprises dealing with such situation. The study was performed through a qualitative investigation based on semi-structured interviews with twenty companies which are part of a ceramic district in the north-east of Italy. More in detail, fourteen of the respondents are owners or CEOs of companies that survived the crisis while six interviews have been held with former owners of enterprises that did not survive. The research strategy used is a multiple case study with inductive approach. The data shows how firms adopted different strategies to survive the crisis, highlighting a considerable difference between the enterprises that survived and the ones that did not. Moreover, a further difference can be identified between the companies that survived but have been able to grow during the economic crisis and the ones that experienced a stable performance or a fall. The findings of the study shows how a combination between product innovation, marketing, internationalization and an open flexible approach is what is needed in order to reach superior performance during a crisis, transforming a threat into opportunity. The role of the leader seems to be the boost of every enterprise defining the success of the business. However, it is still not clear how the personality of the entrepreneur is related to company’s performance, thus this area needs to be developed through further research.
5

A class of generalized shrunken least squares estimators in linear model

Liu, Xiaoming 13 September 2010 (has links)
Modern data analysis often involves a large number of variables, which gives rise to the problem of multicollinearity in regression models. It is well-known that in a linear model, when the design matrix X is nearly singular, then the ordinary least squares (OLS) estimator may perform poorly because of its numerical instability and large variance. To overcome this problem, many linear or nonlinear biased estimators are studied. In this work we consider a class of generalized shrunken least squares (GSLS) estimators that include many well-known linear biased estimators proposed in the literature. We compare these estimators under the mean square error and matrix mean square error criteria. Moreover, a simulation study and two numerical examples are used to illustrate some of the theoretical results.
6

A class of generalized shrunken least squares estimators in linear model

Liu, Xiaoming 13 September 2010 (has links)
Modern data analysis often involves a large number of variables, which gives rise to the problem of multicollinearity in regression models. It is well-known that in a linear model, when the design matrix X is nearly singular, then the ordinary least squares (OLS) estimator may perform poorly because of its numerical instability and large variance. To overcome this problem, many linear or nonlinear biased estimators are studied. In this work we consider a class of generalized shrunken least squares (GSLS) estimators that include many well-known linear biased estimators proposed in the literature. We compare these estimators under the mean square error and matrix mean square error criteria. Moreover, a simulation study and two numerical examples are used to illustrate some of the theoretical results.
7

Large Scale Triaxial Testing of Mechanically Stabilized Earth Retaining Wall Backfill

Garton, Mackenzie 02 October 2013 (has links)
The use of mechanically stabilized earth (MSE) retaining walls has become quite prevalent in highway embankment applications. A design criterion for these walls was originally established by the Federal Highway Administration (FHWA) and has been modified on a state by state basis. Recently, the Texas Department of Transportation (TxDOT) has recorded several wall failures mostly due to excessive settlement and lateral wall deformation and wanted to evaluate the current state design guidelines for regionally available backfill materials. Prior to numerical modeling simulations, material parameters of regionally available backfill needed to be evaluated. As the state guidelines require 85-percent of the wall backfill material to be above the No. 4 sieve, large scale triaxial testing was an option to evaluate strength and volume change parameters. This research used cylindrical specimen 6-inches in diameter and 12- inches in height in a large scale triaxial apparatus. Three types of backfill material were tested and specimens were mixed and compacted in 4 different gradations for each material type. Each gradation was tested at confining stresses corresponding to wall heights of 10, 15, and 20 feet for a total of 36 tests. Basic material parameters such as unit weight and friction angle were evaluated directly from testing, while more complex material parameters were selected from the data for use in the Duncan-Chang elastic constitutive model. This method utilizes hyperbolic curve fitting of both strength and volumetric test data to define soil behavior parameters which include the following: modulus number (K), modulus exponent (n), initial tangent modulus (Ei), failure ratio (Rf ), initial Poisson’s Ratio (νi), and Poisson’s Ratio Parameters G, F, and d. Friction angles from triaxial testing ranged from 32 to 53 degrees having some uncertainty due to inconsistent compaction. The variation in sand and fine size particles in the backfill tended to reduce friction angles, except in the case of Type-B material where density increased due to the high percentage of sand and fines. Duncan-Chang parameters fit reasonably well with experimental data for strength barring some experimental errors. Volumetric parameters were inconclusive due to inconsistent compaction and membrane leakage. Additional testing is needed to provide more sound volumetric data.
8

Robust Portfolio Selection Based on the Shrinkage Estimation / 穩健資產組合選擇: 收縮估計式的應用

莊珮玲, Chuang,Pei-ling Unknown Date (has links)
When portfolio selection is implemented by using the past sample values, parameter uncertainty may lead to suboptimal portfolios. Previous studies of portfolio selection demonstrate that classical approach based on the simple mean estimator is less reliable cause of inherent estimation error. In this paper, we investigate a shrinkage estimator based on Stein’s idea in measuring the expected returns. We apply the research of Jorion (1985) to Taiwan Stock market, present the effects of estimation error on the portfolio selection and demonstrate that the shrinkage estimator is robust and dominates the classical estimator on the MSE criterion. In addition, we also examine the effect of different shrinkage target on the performance of the Bayes-Stein estimator and find that this estimator still has lower risk than the classical sample mean.
9

The influence of mobile payments on the choices and functionings of Micro and Small Enterprise (MSE) entrepreneurs in Lesotho

Hlabeli, Batloung 26 January 2021 (has links)
Background: This study explores the significance of ICT on the capabilities of unbanked MSE entrepreneurs in Lesotho. MSE entrepreneurs are the primary source of income for their families, especially in the context of developing countries. Accordingly, MSEs are fundamental instruments for economic growth, poverty alleviation and source of employment in developing countries. Hence, the country that invests in this business sector is a step closer to accomplishing its MDGs. Purpose: The study explored and empirically assessed the influence of mobile payments among MSE entrepreneurs through a capabilities lens. Given that MSEs are crucial for developing countries, the targeted participants were MSE entrepreneurs from diverse trading industries in Lesotho. Research methodology: The methodology for this study was qualitative. Exploratory and descriptive research methods were used to evaluate the influence of mobile payments on the capabilities of MSE entrepreneurs. This study adopted Kleine's Choice Framework to explore and empirically assess the benefits of mobile payments among MSE entrepreneurs. Data was collected using semi-structured interviews and field notes and analysed using thematic analysis. Key Findings: The findings revealed the use of M-Pesa within the MSE sector enabled microentrepreneurs to accomplish their goals. The findings show that M-Pesa leads to the growth of MSEs. Therefore, entrepreneurs in the MSE business sector are capable of providing food, shelter and clothes for their families through income generated from their enterprises. Additionally, MSE entrepreneurs bank, transfer and receive money through accessible and available mobile payment platforms. However, these entrepreneurs face issues such as network failure, withdrawal amount limits and security risks while using mobile payments. Value of the study: The study contributes to the existing ICT4D and mobile payments literature in Lesotho by discussing the influence of mobile payment through the Choice Framework.
10

Development of an automated system for the measurement of focal ratio degradation of high numerical aperture fibres

Lee, Jooyoung 07 August 2019 (has links)
The thesis presents the development and testing of an automated fibre optic test system for the measurement of focal ratio degradation (FRD) in high numerical aperture fibres. In particular, the fibres under examination are being proposed for use in the Maunakea Spectroscopic Explorer (MSE), a new telescope currently being designed for wide-field surveys of the night sky. A critical subsystem of the MSE is the Fiber Transmission System (FiTS) that connects the focal plane to the telescope’s spectrographs. In preparation for MSE-FiTS, a method of characterizing the focal ratio degradation (FRD), between the input and output of every fibre, of candidate multi-mode fibres is highly important. The ultimate goal is the testing of all 4,332 fibres after assembly and prior to installation on MSE. An optical bench has been constructed to test the performance of an automated characterization system; a variation on the collimated beam test. Herein we present the underlying analysis FRD measurement method, the optical design of the test bench, the motion control system and the software for measuring FRD, and controlling the automated test system. The open-source automation software is also introduced; the Big FiTS Fibre Wrapper (Big FFW). The results of tests performed using the Big FFW on samples of candidate fibres are presented and compared with the results in the literature using manual methods. The results suggest that the candidate MSE fibre meets the science requirement of less than 5% focal ratio degradation for an f/2 input beam measured at the fibre output. There is less than 1% disagreement between the automated measurement method and manual methods reported in the literature. The fully automated system can measure the FRD of up to 10 fibres in a typical MSE fibre bundle configuration. / Graduate

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