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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.
201

The Risk Evaluation of Credit Guarantee and Actuarial Guarantee Fee of Loans to SMEs

Chen, Chin-ming 08 October 2008 (has links)
One of the most important government policies to support and satisfy financing needs for marginal enterprises or special sectors in economic system is to provide credit guarantee. In Taiwan, while Small and Medium Enterprise Credit Guarantee Fund of Taiwan (SMEG) had been established to help small and medium enterprises (SMEs) acquiring bank loans successfully by providing credit guarantee, there is still a need to set up an appropriate credit rating systems for SMEs. This research proposes three kinds of assessment models to the credit risks of SMEG. While Model one employs a firm¡¦s financial performance, substituting debt level and estimated asset value and volatility into the model to derive probability of default (PD). Model two and three utilize a firm¡¦s risk premium observed from the loan rate to estimate credit level. The former belongs to the application of structure-form approach in the credit risk management model, on the other hand, the latter is the reduced-form approach. On the structure-form approach, due to the difficulties in accessing SMEs¡¦ public trade information in Taiwan, we adopt the Private Firm Model developed by Moody's KMV Company. We had also improved this PD evaluation model by taking some peculiar operating characteristics of Taiwan¡¦s SMEs into consideration. On the reduced-form approach, we apply risk-neutral model to estimate a firm¡¦s PD, which then been utilizing to evaluate the expected value of subrogation payment in the case of default. This can further go deeper to calculate the guarantee fee of a loan. The processes used in this model is same as that of actuarial methodology being used to determine the premium of a term insurance. The three credit risk management models proposed in this research are designed to reflect the market information of a SME, and to the applicability of operating in real world case. The empirical results indicate they could adequately reflect the risk levels of the SMEs to a certain extent. We hope to provide the SMEG with a method of evaluating credit risk of SMEs to establish a fairer and more reasonable guarantee fee, and contribute in enhancing and managing credit guarantee mechanism in Taiwan.
202

Examing the Antecedents of Online Disinhibition - the Roles of Internet Attributes and Psychological Factors

Yan, Pei-rong 01 July 2009 (has links)
It can be observed that the anti-normative behaviors occur more frequently in Computer-Mediated-Communication than in face-to-face communication. Internet often let people feel less restraint to use rude or threatening language, leashing harsh criticisms, venting anger or hatred. Thus, the issues surrounding ¡§Toxic Disinhibition¡¨ have attracted more and more concern from society and academia. Our empirical study tries to get the whole picture and proposed a more comprehensive model integrating diverse factors and involving the synthesis of different viewpoints. Accordingly, this paper proceeds to examine and integrate the two important aspects, (1) Internet attributes in which reduced social cue, social presence, controllability, and the fluidity of the identity and (2) psychological state, especially theories of deindividuation.Moreover, different from most prior researches, we consider deindividuation as an important mediating role, not just an antecedent of toxic disinhibition. An empirical survey methodology is applied to test the research model and six hypotheses are developed in this study, and then we use PLS to analyze it. Our empirical results showed that the essential mediating role of deindividuation, also confirming the highly significant with toxic disinhibition. Moreover, we identify major factors that may affect deindividuation. We find that except for reduced social cue, reduced social presence, controllability and fluidity of identity also has significant impact on deindividuation, and then cause toxic disinhibition. In sum, unlike much prior research that has focused on only a limited aspect of toxic disinhibition, we take integrated view and proposed a more comprehensive model therefore be useful to a better understanding of the nature of toxic disinhibition. And this study provides some suggestions for the online disinhibition research.
203

Metrical Properties of Convex Bodies in Minkowski Spaces

Averkov, Gennadiy 12 November 2004 (has links) (PDF)
The objective of this dissertation is the application of Minkowskian cross-section measures (i.e., section and projection measures in finite-dimensional linear normed spaces over the real field) to various topics of geometric convexity in Minkowski spaces, such as bodies of constant Minkowskian width, Minkowskian geometry of simplices, geometric inequalities and the corresponding optimization problems for convex bodies. First we examine one-dimensional Minkowskian cross-section measures deriving (in a unified manner) various properties of these measures. Some of these properties are extensions of the corresponding Euclidean properties, while others are purely Minkowskian. Further on, we discover some new results on the geometry of a simplex in Minkowski spaces, involving descriptions of the so-called tangent Minkowskian balls and of simplices with equal Minkowskian heights. We also give some (characteristic) properties of bodies of constant width in Minkowski planes and in higher dimensional Minkowski spaces. This part of investigation has relations to the well known \emph{Borsuk problem} from the combinatorial geometry and to the widely used monotonicity lemma from the theory of Minkowski spaces. Finally, we study bodies of given Minkowskian thickness ($=$ minimal width) having least possible volume. In the planar case a complete description of this class of bodies is given, while in case of arbitrary dimension sharp estimates for the coefficient in the corresponding geometric inequality are found. / Die Dissertation befasst sich mit Problemen fuer spezielle konvexe Koerper in Minkowski-Raeumen (d.h. in endlich-dimensionalen Banach-Raeumen). Es wurden Klassen der Koerper mit verschiedenen metrischen Eigenschaften betrachtet (z.B., Koerper konstante Breite, reduzierte Koerper, Simplexe mit Inhaltsgleichen Facetten usw.) und einige kennzeichnende und andere Eigenschaften fuer diese Klassen herleitet.
204

Reduced Density Matrix Approach to the Laser-Assisted Electron Transport in Molecular Wires

Welack, Sven 07 April 2006 (has links) (PDF)
The electron transport through a molecular wire under the influence of an external laser field is studied using a reduced density matrix formalism. The full system is partitioned into the relevant part, i.e. the wire, electron reservoirs and a phonon bath. An earlier second-order perturbation theory approach of Meier and Tannor for bosonic environments which employs a numerical decomposition of the spectral density is used to describe the coupling to the phonon bath and is extended to deal with the electron transfer between the reservoirs and the molecular wire. Furthermore, from the resulting time-nonlocal (TNL) scheme a time-local (TL) approach can be determined. Both are employed to propagate the reduced density operator in time for an arbitrary time-dependent system Hamiltonian which incorporates the laser field non-perturbatively. Within the TL formulation, one can extract a current operator for the open quantum system. This enables a more general formulation of the problem which is necessary to employ an optimal control algorithm for open quantum systems in order to compute optimal control fields for time-distributed target states, e.g. current patterns. Thus, we take a fundamental step towards optimal control in molecular electronics. Numerical examples of the population dynamics, laser controlled current, TNL vs. TL and optimal control fields are presented to demonstrate the diverse applicability of the derived formalism.
205

Total delay optimization for column reduction multipliers considering non-uniform arrival times to the final adder

Waters, Ronald S. 26 June 2014 (has links)
Column Reduction Multiplier techniques provide the fastest multiplier designs and involve three steps. First, a partial product array of terms is formed by logically ANDing each bit of the multiplier with each bit of the multiplicand. Second, adders or counters are used to reduce the number of terms in each bit column to a final two. This activity is commonly described as column reduction and occurs in multiple stages. Finally, some form of carry propagate adder (CPA) is applied to the final two terms in order to sum them to produce the final product of the multiplication. Since forming the partial products, in the first step, is simply forming an array of the logical AND's of two bits, there is little opportunity for delay improvement for the first step. There has been much work done in optimizing the reduction stages for column multipliers in the second reduction step. All of the reduction approaches of the second step result in non-uniform arrival times to the input of the final carry propagate adder in the final step. The designs for carry propagate adders have been done assuming that the input bits all have the same arrival time. It is not evident that the non-uniform arrival times from the columns impacts the performance of the multiplier. A thorough analysis of the several column reduction methods and the impact of carry propagate adder designs, along with the column reduction design step, to provide the fastest possible final results, for an array of multiplier widths has not been undertaken. This dissertation investigates the design impact of three carry propagate adders, with different performance attributes, on the final delay results for four column reduction multipliers and suggests general ways to optimize the total delay for the multipliers. / text
206

Condensation of pure hydrocarbons and zeotropic mixtures in smooth horizontal tubes

MacDonald, Malcolm 21 September 2015 (has links)
A study of the condensation of hydrocarbons and zeotropic hydrocarbon mixtures in smooth horizontal tubes was conducted. Measurements of condensation heat transfer coefficients and frictional pressure drop were taken over a range of mass fluxes (G = 150 – 450 kg m-2 s-1), a range of reduced pressures (Pr = 0.25 - 0.95), for two tube diameters (D = 7.75 and 14.45 mm), several working fluid-to-coolant temperature differences (ΔTLM = 3 – 14°C) and temperature glides (ΔTGlide) between 7 - 14°C. The wide range of conditions investigated in this study provides considerable insight on the transport phenomena influencing condensation in pure fluids and their mixtures. The trends in heat transfer coefficient and frictional pressure gradient are discussed and compared with the predictions of correlations from the literature. The results of the experiments, combined with previous flow visualization studies on hydrocarbons, were used to develop physically consistent heat transfer and frictional pressure gradient models that are applicable to pure fluids and zeotropic mixtures. A framework was developed for zeotropic mixture condensation that recommends a specific modeling approach based on the observed trends in the heat transfer coefficient and the points of deviations from pure fluid trends. The documentation of the condensation heat transfer and pressure drop behavior of environmentally friendly refrigerants, and the development of accurate correlations, will facilitate their widespread introduction as a working fluid for refrigeration cycles. Furthermore, the accurate pure fluid models, which serve as a baseline case for zeotropic mixture modeling, yield more effective predictions of zeotropic mixture condensation, which will lead to increased efficiencies of chemical processing plants.
207

Simplified calculation of rHCT basis functions for an arbitrary splitting

Weise, Michael 06 February 2015 (has links) (PDF)
Reduced Hsieh-Clough-Tocher elements are triangular C1-elements with only nine degrees of freedom. Simple formulas for the basis functions of reduced Hsieh-Clough-Tocher elements based on the edge vectors of the triangle have been given recently for a barycentric splitting. We generalise these formulas to the case of an arbitrary splitting point.
208

Advanced computational techniques for unsteady aerodynamic-dynamic interactions of bluff bodies

Prosser, Daniel T. 21 September 2015 (has links)
Interactions between the aerodynamics and dynamics of bluff bodies are important in many engineering applications, including suspension bridges, tall buildings, oil platforms, wind turbine towers, air drops, and construction with cranes. In the rotorcraft field, bluff bodies are commonly suspended underneath the vehicle by tethers. This approach is often the only practical way to deliver a payload in a reasonable amount of time in disaster relief efforts, search-and-rescue operations, and military operations. However, currently a fundamental understanding of the aerodynamics of these bluff bodies is lacking, and accurate dynamic simulation models for predicting the safe flying speed are not available. In order to address these shortcomings, two main advancements are presented in this thesis. The aerodynamics of several three-dimensional canonical bluff bodies are examined over a range of Reynolds numbers representative of wind-tunnel-scale to full-scale models. Numerical experiments are utilized, with a focus on uncertainty analysis and validation of the computations. Mean and unsteady forces and moments for these bluff bodies have been evaluated, and empirical models of the shear layer characteristics have been extracted to quantify the behaviors and provide predictive capability. In addition, a physics-based reduced-order simulation model has been developed for bluff bodies. The physics-based approach is necessary to ensure that the predicted behavior of new configurations is accurate, and it is made possible by the breakthroughs in three-dimensional bluff body aerodynamics presented in this thesis. The integrated aerodynamic forces and moments and dynamic behavior predicted by model are extensively validated with data from wind tunnels, flight tests, and high-fidelity computations. Furthermore, successful stability predictions for tethered loads are demonstrated. The model is applicable to the simulation of any generic bluff body configuration, is readily extensible, and has low computational cost.
209

Factorization in unitary loop groups and reduced words in affine Weyl groups.

Pittman-Polletta, Benjamin Rafael January 2010 (has links)
The purpose of this dissertation is to elaborate, with specific examples and calculations, on a new refinement of triangular factorization for the loop group of a simple, compact Lie group K, first appearing in Pickrell & Pittman-Polletta 2010. This new factorization allows us to write a smooth map from the unit circle into K (having a triangular factorization) as a triply infinite product of loops, each of which depends on a single complex parameter. These parameters give a set of coordinates on the loop group of K.The order of the factors in this refinement is determined by an infinite sequence of simple generators in the affine Weyl group associated to K, having certain properties. The major results of this dissertation are examples of such sequences for all the classical Weyl groups.We also produce a variation of this refinement which allows us to write smooth maps from the unit circle into the special unitary group of n by n matrices as products of 2n+1 infinite products. By analogy with the semisimple analog of our factorization, we suggest that this variation of the refinement has simpler combinatorics than that appearing in Pickrell & Pittman-Polletta 2010.
210

Methods for reduced platen compression (RPC) test specimen cutting locations using micro-CT and planar radiographs

Lemmon, Heber 30 September 2004 (has links)
This study looks at improving reduced platen compression (RPC) specimen preparation procedures by developing a better method for locating the ideal RPC specimen on each bone. These improvements are aimed at decreasing the amount of time required to complete an RPC analysis and improving the quality of the obtained results. High-resolution micro-CT scans are used to gain a better understanding of rat long bone anatomy by quantifying the location, shape, and orientation of the growth plate, primary spongiosa, and secondary spongiosa. Micro-CT analysis shows that there are easily identifiable external landmarks on the anterior side of both tibias and femurs that identify the end of the growth plate and the point at which the top of an ideal RPC specimen should be located. The landmarks are the most proximal tip of the patellar surface for the femur and the base of the tibial tuberosity for the tibia. This study also analyzes the effect of variations in the actual RPC specimen location from the ideal location and the effect of different platen sizes on test results using BMD as a surrogate for mechanical properties. The analysis shows that the BMD increases as the target RPC specimen location approaches the growth plate and decreases on moving away from the growth plate. The study also indicates that consistency is necessary when obtaining RPC specimens to avoid error due to variation from the specified landmark. Additionally, the BMD decreased as the diameter of the platen is reduced. Choosing platen size then becomes a trade off between testing the greatest amount of cancellous bone possible and potentially higher load sharing by the cortical shell with larger platen sizes as well as the risk of compressing cortical bone during the test.

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