Distortions that affect macroeconomic outcomes are an important avenue through which we can explain differences in cross country output and productivity. In this thesis I concentrate on two types of distortions, political economy and informational distortions. In Chapter one, I build a model of intermediated corruption where interactions between government bureaucrats and those who bribe them are mediated by a third party. I show that intermediation has significant effects on the incidence of corruption and the prices entrepreneurs pay for permits. When corruption is particularly acute, measures that increase the frequency with which government bureaucrats are audited often have the undesirable result of increasing the prevalence of corruption because of intermediation. In Chapter two I explore the link between corruption and inequality by building a model in which tax collectors are corrupt. I find that as inequality increases, the frequency of corrupt transactions increases as well. I also find that where corruption is more severe, because wealthier individuals tend to pay lower taxes, inequality is higher. I perform a few quantitative experiments to better understand this linkage. Chapter three explores distortions that are caused by adverse selection in markets with search frictions. I find that when participants are concerned about the information they reveal through their interactions in the market, the distortions to liquidity are deeper and that equilibrium selection is significantly affected. I also find that markets with reputational concerns are more sensitive to outside shocks.

Distortions that affect macroeconomic outcomes are an important avenue through which we can explain differences in cross country output and productivity. In this thesis I concentrate on two types of distortions, political economy and informational distortions. In Chapter one, I build a model of intermediated corruption where interactions between government bureaucrats and those who bribe them are mediated by a third party. I show that intermediation has significant effects on the incidence of corruption and the prices entrepreneurs pay for permits. When corruption is particularly acute, measures that increase the frequency with which government bureaucrats are audited often have the undesirable result of increasing the prevalence of corruption because of intermediation. In Chapter two I explore the link between corruption and inequality by building a model in which tax collectors are corrupt. I find that as inequality increases, the frequency of corrupt transactions increases as well. I also find that where corruption is more severe, because wealthier individuals tend to pay lower taxes, inequality is higher. I perform a few quantitative experiments to better understand this linkage. Chapter three explores distortions that are caused by adverse selection in markets with search frictions. I find that when participants are concerned about the information they reveal through their interactions in the market, the distortions to liquidity are deeper and that equilibrium selection is significantly affected. I also find that markets with reputational concerns are more sensitive to outside shocks.

This study examined the relationship between the sub-components of Holland's Self-Directed Search and independent, objective measures of ability using a comprehensive battery of well-validated tests of primary abilities corresponding to each of Holland's six vocational interest types. The sample consisted of 149 female undergraduate students, ages 18-25. Correlation of the ability measure test scores with the four Self-Directed Search subcomponents revealed that the subtests were not related to corresponding measures of ability in a consistent fashion. Implications for the use of the Self-Directed Search in assessing abilities are discussed along with suggestions for future research investigating the relationhip between interest in ventories and the measurement of primary abilities.

Note from the Library: The fulltext electronic version of this thesis has been removed due to restricted content. Please contact the Unisa Library for more details. / Industrial and Organisational Psychology / M.A. (Industrial Psychology)

Το πρόβλημα εύρεσης συντομότερων διαδρομών είναι ένα από τα πιο θεμελιώδη προβλήματα μονοκριτηριακής βελτιστοποίησης σε δίκτυα. Σε αυτό το πρόβλημα αναζητείται η συντομότερη διαδρομή μεταξύ δύο δεδομένων σημείων ελαχιστοποιώντας ένα κριτήριο κόστους. Σε πολλές εφαρμογές ωστόσο, μας ενδιαφέρουν περισσότερα από ένα κριτήρια προς βελτιστοποίηση. Για παράδειγμα, στην εύρεση διαδρομών σε ένα οδικό δίκτυο με διόδια, μας ενδιαφέρει εκτός από την διανυμένη απόσταση και η ελαχιστοποίηση του χρόνου και του κόστους. Παρόμοια παραδείγματα βρίσκουμε και στον χώρο των δικτύων τηλεπικοινωνιών, όπου εξετάζονται κριτήρια όπως η καθυστέρηση, η πιθανότητα λάθους, ο αριθμός συνδέσμων και άλλα. Σε αυτές τις περιπτώσεις η καλύτερη λύση δεν μπορεί να οριστεί με μονοσήμαντο τρόπο, και συνεπώς καταφεύγουμε σε αντισταθμίσεις μεταξύ των παραγόντων, που είναι γνωστές ως σύνολο λύσεων κατά Pareto. Παρόλο που για το πρόβλημα μονοκριτηριακής εύρεσης συντομότερων διαδρομών υπάρχουν πολλοί αποδοτικοί αλγόριθμοι για την επίλυση του προβλήματος, το αντίστοιχο πολυκριτηριακό πρόβλημα είναι πολύ πιο σύνθετο. Μέχρι τώρα, αυτό το πρόβλημα έχει αποδειχθεί ότι είναι NP-πλήρες. Επιπλέον, έχει αποδειχθεί ότι το πλήθος των λύσεων σε αυτό το πρόβλημα αυξάνεται εκθετικά σε σχέση με το μέγεθος της εισόδου. Υπάρχουν δύο βασικές προσεγγίσεις επίλυσης τέτοιων προβλημάτων, όπου εξετάζονται πολλαπλά κριτήρια. α) Η πρώτη μέθοδος βρίσκει προσεγγιστικές λύσης κατά έναν ορισμένο παράγοντα. Οι προσεγγιστικές μέθοδοι δεν βρίσκουν απαραίτητα ακριβείς λύσεις, αλλά είναι σχετικά γρήγορες και προσφέρουν εγγύηση για το ποσοστό απόκλισης από την βέλτιστη λύση. β) Η δεύτερη μέθοδος χρησιμοποιεί ευρετικές βελτιώσεις για να επιταχύνει τους ήδη υπάρχοντες αλγορίθμους. Τέτοιες τεχνικές βρίσκουν ακριβείς λύσεις, και το ζητούμενο είναι να επιτευχθεί μια πολύ καλή χρονική απόδοση. Στην παρούσα διπλωματική εργασία επικεντρωνόμαστε στην δεύτερη μέθοδο, υποκινούμενοι από την μεγάλη ζήτηση πρακτικών εφαρμογών για εύρεση αποτελεσματικής και ακριβούς λύσης του προβλήματος συντομότερων διαδρομών υπό πολλαπλά κριτήρια. Πιο συγκεκριμένα, στην εργασία αυτή παρουσιάζουμε ένα ενοποιημένο πλαίσιο για την αποδοτική επίλυση αυτών των προβλημάτων. Προτείνουμε νέες μεθόδους ή βελτιώσεις των υπαρχόντων. Υλοποιήσαμε τις μεθόδους που παρουσιάζουμε συνοδεύοντάς τις με μια εκτενή πειραματική μελέτη πάνω σε δίκτυα ευρείας κλίμακας. / We present new implementations of heuristic algorithms for the solution of the multiobjective shortest path problem, using a new graph structure specifically suited for large scale road networks. We enhance the heuristics with further optimizations and experimentally evaluate the performance of our enhanced implementation on real world road networks achieving 10 times better performance with respect to the best previous study.

Note from the Library: The fulltext electronic version of this thesis has been removed due to restricted content. Please contact the Unisa Library for more details. / Industrial and Organisational Psychology / M.A. (Industrial Psychology)

Submitted by Paula Onuchic (p.onuchic@gmail.com) on 2015-04-14T20:27:08Z No. of bitstreams: 1 ABNT-Paula Onuchic.pdf: 497909 bytes, checksum: d5bb3b15c7946403b58a3c866e03c2e6 (MD5) / Approved for entry into archive by Vera Lúcia Mourão (vera.mourao@fgv.br) on 2015-04-14T20:28:30Z (GMT) No. of bitstreams: 1 ABNT-Paula Onuchic.pdf: 497909 bytes, checksum: d5bb3b15c7946403b58a3c866e03c2e6 (MD5) / Made available in DSpace on 2015-04-15T12:36:57Z (GMT). No. of bitstreams: 1 ABNT-Paula Onuchic.pdf: 497909 bytes, checksum: d5bb3b15c7946403b58a3c866e03c2e6 (MD5) Previous issue date: 2015-03-19 / I use the competitive search framework to model a job market with heterogeneous workers in which there is a moral hazard problem in the employer-worker relation. In this setting, I can predict how contracts react to changes in underlying parameters of the market (in particular, the production risk), as well as how the probability of each type of worker being hired responds. My main finding is that while at the individual level there is a negative risk- incentive trade-off, general equilibrium effects imply that the effect can be positive at the aggregate level depending on the market search frictions and the distribution of types. My re- sults help shed some light on some puzzling empirical findings on the risk-incentives trade-off. / Usando a abordagem de competitive search, modelo um mercado de trabalho com trabalhadores heterogêneos no qual há um problema de risco moral na relação entre firmas e trabalhadores. Nesse contexto, consigo prever como contratos reagem a mudanças nos parâmetros do mercado (em particular, o risco de produção), assim como a variação da probabilidade dos trabalhadores serem contratados. Minha contribuição principal é ver que, no nível individual, existe uma relação negativa entre risco e incentivos, mas efeitos de equilíbrio geral implicam que essa relação pode ser positiva no nível agregado. Esse resultado ajuda a esclarecer resultados empíricos contraditórios sobre a relação entre risco e incentivos.

CHOICES, the career planning computer program, was evaluated by interviewing 35 grade 11 and 12 students. Using the critical incident technique, reports were elicited of what facilitated or hindered their career planning. These collected incidents were categorized by similarity to provide counsellors and others with a map of exactly what the program does to help or hinder career planning. This map potentially enables counsellors to capitalize on benefits and to minimize possible detriments. Secondly, this map was qualitatively compared to a similar evaluation of the Self-Directed Search. Overall, it was found that the two interventions have differing advantages and disadvantages. CHOICES stresses reality constraints, specificity and extrinsic work features. The SDS underlines self-awareness and an understanding of the matching process. It seems that CHOICES is more appropriate for planning and specific decisions regarding options while the SDS tends to focus on general exploration and decisions regarding fields. The writer wishes to express his appreciation to the following persons: To Dr. Larry Cochran, research supervisor, whose patience, availability and countless hours over six years made this study possible. To Dr. Marv Westwood, whose continual support especially for the clinical comprehensive, was greatly appreciated. To Dr. Bill Borgen, whose encouragement at the appropriate time enabled me to perservere. To Dr. Norm Amundson, whose inspired synthesis made the oral presentation smoother. To Dr. Ron MacGregor, whose suggestions were appreciated. To the students, to the staff of Matthew McNair Senior Secondary and to the counsellor Mike Casselman, whose co-operation and support made this study possible. To Mrs. Irma Eichler, for her devoted time and effort in typing this dissertation. And finally, to my parents Rene and Lucille, to my sisters Louise and Anita, and to my brother Jean, for their continual support and encouragement. / Education, Faculty of / Educational and Counselling Psychology, and Special Education (ECPS), Department of / Graduate

Optimisation is one of the most important and challenging part of any engineering design. In real world design problems one faces multiobjective optimisation under constraints. The optimal solution in these cases is not unique because the objectives can contradict each other. In such cases, a set of optimal solutions which forms a Pareto frontier in the objective space is considered. There are many algorithms to generate the Pareto frontier. However, only a few of them are potentially capable of providing an evenly distributed set of the solutions. Such a property is especially important in real-life design because a decision maker is usually able to analyse only a very limited quantity of solutions. This thesis consists of two main parts. At first, it develops and gives the detailed description of two different algorithms that are able to generate an evenly distributed Pareto set in a general formulation. One is a classical approach and called Directed Search Domain (DSD) and the other, the cylindrical constraint evolutionary algorithm (CCEA), is a hybrid population based method. The efficiency of the algorithms are demonstrated by a number of challenging test cases and the comparisons with the results of the other existing methods. It is shown that the proposed methods are successful in generating the Pareto solutions even when some existing methods fail. In real world design problems, deterministic approaches cannot provide a reliable solution as in the event of uncertainty, deterministic optimal solution would be infeasible in many instances. Therefore a solution less sensitive to problem perturbation is desirable. This leads to the robust solution which is the focus of the second part of the thesis. In the literature, there are some techniques tailored for robust optimisation. However, most of them are either computationally expensive or do not systematically articulate the designer preferences into a robust solution. In this thesis, by introducing a measure for robustness in multiobjective context, a tunable robust function (TRF) is presented. Including the TRF in the problem formulation, it is demonstrated that the desirable robust solution based on designer preferences can be obtained. This not only provides the robust solution but also gives a control over the robustness level. The method is efficient as it only increases the dimension of the problem by one irrespective of the dimension of the original problem.

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