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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.

Zur Wirksamkeit der "Förderung beruflicher Weiterbildung" (FbW)

Jansen, Marcus. January 2005 (has links)
Konstanz, Univ., Diplomarb., 2005.

Discrete Optimization Problems in Popular Matchings and Scheduling

Powers, Vladlena January 2020 (has links)
This thesis focuses on two central classes of problems in discrete optimization: matching and scheduling. Matching problems lie at the intersection of different areas of mathematics, computer science, and economics. In two-sided markets, Gale and Shapley's model has been widely used and generalized to assign, e.g., students to schools and interns to hospitals. The goal is to find a matching that respects a certain concept of fairness called stability. This model has been generalized in many ways. Relaxing the stability condition to popularity allows to overcome one of the main drawbacks of stable matchings: the fact that two individuals (a blocking pair) can prevent the matching from being much larger. The first part of this thesis is devoted to understanding the complexity of various problems around popular matchings. We first investigate maximum weighted popular matching problems. In particular, we show various NP-hardness results, while on the other hand prove that a popular matching of maximum weight (if any) can be found in polynomial time if the input graph has bounded treewidth. We also investigate algorithmic questions on the relationship between popular, stable, and Pareto optimal matchings. The last part of the thesis deals with a combinatorial scheduling problem arising in cyber-security. Moving target defense strategies allow to mitigate cyber attacks. We analyze a strategic game, PLADD, which is an abstract model for these strategies.

Multi-Object Shape Retrieval Using Curvature Trees

Alajlan, Naif January 2006 (has links)
This work presents a geometry-based image retrieval approach for multi-object images. We commence with developing an effective shape matching method for closed boundaries. Then, a structured representation, called curvature tree (CT), is introduced to extend the shape matching approach to handle images containing multiple objects with possible holes. We also propose an algorithm, based on Gestalt principles, to detect and extract high-level boundaries (or envelopes), which may evolve as a result of the spatial arrangement of a group of image objects. At first, a shape retrieval method using triangle-area representation (TAR) is presented for non-rigid shapes with closed boundaries. This representation is effective in capturing both local and global characteristics of a shape, invariant to translation, rotation, scaling and shear, and robust against noise and moderate amounts of occlusion. For matching, two algorithms are introduced. The first algorithm matches concavity maxima points extracted from TAR image obtained by thresholding the TAR. In the second matching algorithm, dynamic space warping (DSW) is employed to search efficiently for the optimal (least cost) correspondence between the points of two shapes. Experimental results using the MPEG-7 CE-1 database of 1400 shapes show the superiority of our method over other recent methods. Then, a geometry-based image retrieval system is developed for multi-object images. We model both shape and topology of image objects including holes using a structured representation called curvature tree (CT). To facilitate shape-based matching, the TAR of each object and hole is stored at the corresponding node in the CT. The similarity between two CTs is measured based on the maximum similarity subtree isomorphism (MSSI) where a one-to-one correspondence is established between the nodes of the two trees. Our matching scheme agrees with many recent findings in psychology about the human perception of multi-object images. Two algorithms are introduced to solve the MSSI problem: an approximate and an exact. Both algorithms have polynomial-time computational complexity and use the DSW as the similarity measure between the attributed nodes. Experiments on a database of 13500 medical images and a database of 1580 logo images have shown the effectiveness of the proposed method. The purpose of the last part is to allow for high-level shape retrieval in multi-object images by detecting and extracting the envelope of high-level object groupings in the image. Motivated by studies in Gestalt theory, a new algorithm for the envelope extraction is proposed that works in two stages. The first stage detects the envelope (if exists) and groups its objects using hierarchical clustering. In the second stage, each grouping is merged using morphological operations and then further refined using concavity tree reconstruction to eliminate odd concavities in the extracted envelope. Experiment on a set of 110 logo images demonstrates the feasibility of our approach.

Predictors of Primary Care Career Choice: A Review of AMCAS Applications of Four Graduating Classes at a New Medical School

Korenstein, Alyssa 10 May 2017 (has links)
A Thesis submitted to The University of Arizona College of Medicine - Phoenix in partial fulfillment of the requirements for the Degree of Doctor of Medicine. / The United States (U.S.) is currently facing a shortage of primary care physicians, an issue particularly salient in Arizona. The purpose of this project is to investigate predictors of students entering primary care specialties that may be apparent from their American Medical College Application Service (AMCAS) applications, in order to best serve the needs of the physician workforce. We hypothesized that factors such as female gender, older age at application (“non‐traditional” students), and being raised in a rural/underserved community background may be predictors of students who choose primary care fields. AMCAS applications are completed by aspiring medical students and contain demographic information including gender, age, race, languages spoken, and family/community characteristics. Data provided also include academic factors such as college major, grade point average (GPA), and Medical College Admissions Test (MCAT) scores. Other subjective data reported by applicants include descriptions of extracurricular activities and a personal statement. The National Resident Matching Program (NRMP) is the system used by graduating students during the last semester of medical school to match students with their choice of specialty and the residency program wherein they will spend an additional three years, minimum, in training. Based on the Association of American Medical Colleges (AAMC) designations, we are considering primary care to be Family Medicine, Pediatrics, Internal Medicine, and Medicine‐Pediatrics. We examined data from AMCAS applications of all 149 students who graduated from the University of Arizona College of Medicine‐Phoenix between 2011‐2014, and compared to their NRMP match outcomes. Comparisons were made between non‐primary care versus primary care‐overall, as well as Family Medicine alone versus all other matches given the increasing rate of specialization within Internal Medicine and Pediatrics. Multiple logistic regression revealed two predictors of primary care career choice compared to non‐primary care: having more siblings (P=.003) and non‐physician parents (P=.017). Specific to Family Medicine, several predictors were identified compared to the non‐Family Medicine cohort: a slightly greater percentage of earned community college credits (P=.03), lower MCAT physical science (P=.009), higher MCAT verbal scores (P=.02), and lower paternal education (P=.003). Our analyses suggest having a greater number of siblings and non‐physician parents may predict primary care career choice. Specific to Family Medicine, academic factors including community college enrollment and MCAT scores may be of predictive value. Though the exact implications behind these findings are unclear, it is important to continually examine such data as medical schools can shape admissions selection criteria targeted at increasing the number of graduates seeking careers in primary care.

Arbitrated matching: formulation, protocol and strategies.

January 1992 (has links)
by Choi Ka Wai. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1992. / Includes bibliographical references (leaves 54-55). / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- The Matching Process --- p.1 / Chapter 1.2 --- Centralization --- p.2 / Chapter 1.3 --- One-off Approach --- p.3 / Chapter 1.4 --- Our Approach --- p.4 / Chapter 1.5 --- Organization --- p.5 / Chapter 2 --- Decision Theory --- p.6 / Chapter 2.1 --- Ordinal Preference --- p.6 / Chapter 2.1.1 --- Strict Preference and Indifference --- p.6 / Chapter 2.1.2 --- Weak Preference --- p.8 / Chapter 2.2 --- Utility Theory --- p.8 / Chapter 2.3 --- Group Decision Making --- p.9 / Chapter 2.3.1 --- Social Choice Theory --- p.9 / Chapter 2.3.2 --- Bargaining --- p.11 / Chapter 3 --- The Matching Rule --- p.14 / Chapter 3.1 --- The Marriage Model --- p.15 / Chapter 3.2 --- Stability --- p.16

Essays in Microeconomics

Zanardo, Enrico January 2017 (has links)
This dissertation analyzes problems related to the the economics of incomplete information and to the theory of matching markets. Chapter 1 defines a family of functions that measure the distance between opinions; Chapter 2 investigates how to measure the cost of an experiment; and Chapter 3 studies a model of two-sided matching with countably many agents. Chapter 1 introduces six axioms that a measure of disagreement should satisfy, and characterizes all the functions that satisfy them. The disagreement measures characterized generalize the Renyi divergences, and include the Kullback-Leibler divergence and the Bhattacharyya distance. Two applications are then studied. The first application provides a necessary and sufficient condition under which public information reduces expected disagreement between Bayesian agents. The second application shows that the measures of disagreement here defined are useful to understand trading under heterogeneous beliefs. Trade volume and gains from trade are increasing in some of the measures of disagreement. Chapter 2 introduces seven postulates for a cost of information function. The main result of this chapter is the proof that there exists a unique function that satisfies these postulates. Differently from the cost functions commonly used, the function found in Chapter 2 is independent of the experimenter’s beliefs, and it is additive in independent experiments. Similarly to other cost functions, it is increasing in the informativeness of the experiment, and it is separable in the signal realizations. Chapter 3 analyzes two-sided one-to-one matching with countably infinite agents. It shows that the set of stable matching is non-empty if and only if agents’ preferences admit a maximum on all subsets. This requires generalizing the Deferred Acceptance algorithm, which also allows to find the man-optimal and woman-optimal stable matchings. It is then shown that, like in the finite model, the set of stable matchings is a complete lattice under the preferences induced by men (or women). Unlike in finite models, the set of matched agents may vary across stable matchings and some implications for dynamic matching markets are discussed.

Fractal based speech recognition and synthesis

Fekkai, Souhila January 2002 (has links)
No description available.

Comparison of Salient Feature Descriptors

Farzaneh, Sara January 2008 (has links)
<p>In robot navigation, and image content searches reliable salient features are of pivotal importance. Also in biometric human recognition, salient features are increasingly used. </p><p>Regardless the application, image matching is one of the many problems in computer </p><p>vision, including object recognition. </p><p> </p><p>This report investigates some salient features to match sub-images of different images. </p><p>An underlying assumption is that sub-images, also called image objects, or objects, are </p><p>possible to recognize by the salient features that can be recognized independently. </p><p> </p><p>Since image objects are images of 3D objects, the salient features in 2D images must be </p><p>invariant to reasonably large viewing direction and distance (scale) changes. These </p><p>changes are typically due to 3D rotations and translations of the 3D object with respect to </p><p>the camera. Other changes that influence the matching of two 2D image objects is </p><p>illumination changes, and image acquisition noise. </p><p> </p><p>This thesis will discuss how to find the salient features and will compare them with </p><p>respect to their matching performance. Also it will explore how these features are </p><p>invariant to rotation and scaling.</p>

Wide baseline matching with applications to visual servoing

Tell, Dennis January 2002 (has links)
No description available.

On interaction and efficiency : prematch investments with hidden characteristics

Bidner, Christopher 05 1900 (has links)
I develop three models that are designed to aid in the analysis of environments in which agents i) benefit from interacting with others, and ii) optimally choose their characteristics mindful of the fact that such choices will influence the quality of interaction that they can expect. Of central interest is the ways in which a concern for interaction affects the efficiency with which agents choose their characteristics. The first two models contrast with previous work in that each agents' relevant characteristics are both unobserved and endogenously determined. The first model provides an explanation for credentialism in the labour market, and demonstrates how a concern for interaction can lead to over-investment in the relevant characteristic. The second model is motivated by human capital development in the presence of peer effects, and demonstrates how a concern for interaction can exacerbate an inherent under-investment problem. The third model retains the feature of unobserved characteristics, and contrasts with previous work by embedding frictions in the process by which agents compete for partners. The model is set in a labour market and demonstrates that outcomes of interest (equilibrium matching patterns, income, inequality and welfare) are generally not monotonic in the level of frictions.

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