Eine mit Polyethylen abgeschirmte Americium-Beryllium-Quelle wurde bzgl. ihres schnellen und thermischen Neutronenfeldes sowie Photonenfeldes durch Messungen und Simulationen quantifiziert. Dafür wurden Strahlungsfeldgrößen wie spektrale Teilchenflussdichten, Teilchenflussdichten, UmgebungsÄquivalentdosisleistungen und Richtungs-Äquivalentdosisleistungen für die jeweiligen Felder in unterschiedlichen Abständen der Strahlungsquelle bestimmt. Die ermittelten Ergebnisse werden verwendet, um einen neuen Bestrahlungsstand als Referenzfeld für Neutronen und Photonen zu errichten.:Einleitung 1. Theoretische Grundlagen 1.1. Strahlungsfeldgrößen 1.1.1. Radiometrische Größen 1.1.2. Interaktionskoeffizienten 1.1.3. Dosimetrische Größen 1.1.4. Fluenz-zu-Dosis-Konversionskoeffizienten 1.2. Photonen 1.2.1. Wechselwirkung mit Materie 1.2.2. Nachweis durch Szintillationsdetektoren 1.3. Neutronen 1.3.1. Klassifizierung 1.3.2. Wechselwirkung mit Materie 1.3.3. Nachweis schneller Neutronen durch organische Szintillationsdetektoren 1.3.4. Nachweis thermischer Neutronen durch ³He-Zählrohre 1.4. Americium-Beryllium-Quellen 1.4.1. Neutronenerzeugung 1.4.2. Abschirmung 1.5. Detektoren 1.5.1. Szintillationsdetektoren 1.5.2. ³He-Zählrohre 1.6. Digitale Pulsverarbeitung 1.6.1. Pulsformdiskriminierung mit organischen Szintillationsdetektoren 1.7. Monte-Carlo-Strahlungstransportsimulationen 2. Geräte und Materialien 3. Methoden 3.1. Quantifizierung des schnellen Neutronenfeldes 3.1.1. PFD-unterstützte Flugzeitmethode 3.1.2. Einfache Entfaltungstechnik 3.2. Quantifizierung des thermischen Neutronenfeldes 3.3. Quantifizierung des Photonenfeldes 4. Messungen 4.1. Messung 1 4.2. Messung 2 4.3. Messung 3 4.4. Messung 4 4.5. Messung 5 4.6. Messung 6 4.7. Messung 7 4.8. Messung 8 4.9. Messung 9 4.10. Messung 10 5. Simulationen mit FLUKA 5.1. Nachmodellierung der Versuchsaufbauten 5.2. Nachbildung der Strahlungsfelder 5.2.1. Bestimmung der Korrekturfaktoren 5.3. Simulierte Größen 6. Ergebnisse 6.1. Quantifizierung des schnellen Neutronenfeldes 6.1.1. Strahlungsfeldgrößen mittels des Stilbendetektors 6.1.2. Strahlungsfeldgrößen mittels der Plausibilitätsmessungen 6.1.3. Strahlungsfeldgrößen mittels der FLUKA-Simulationen 6.2. Quantifizierung des thermischen Neutronenfeldes 6.2.1. Strahlungsfeldgrößen mittels des ³He-Zählrohrs 6.2.2. Strahlungsfeldgrößen mittels der FLUKA-Simulationen 6.3. Quantifizierung des Photonenfeldes 6.3.1. Strahlungsfeldgrößen mittels des CeBr₃-Detektors 6.3.2. Strahlungsfeldgrößen mittels der Plausibilitätsmessungen 6.3.3. Strahlungsfeldgrößen mittels der FLUKA-Simulationen 7. Diskussion 7.1. Quantifizierung des schnellen Neutronenfeldes 7.1.1. Spektrale Teilchenflussdichten 7.1.2. Umgebungs-Äquivalentdosisleistungen 7.2. Quantifizierung des thermischen Neutronenfeldes 7.2.1. Teilchenflussdichten 7.3. Quantifizierung des Photonenfeldes 7.3.1. Teilchenflussdichten der Photonen mit den Energien 511 keV, 2,2 MeV und 4,4 MeV 7.3.2. Umgebungs-Äquivalentdosisleistungen 7.3.3. Richtungs-Äquivalentdosisleistungen 8. Zusammenfassung A. Bestimmte Strahlungsfeldgrößen A.1. Schnelles Neutronenfeld A.1.1. Spektrale Teilchenflussdichten A.1.2. Umgebungs-Äquivalentdosisleistungen A.2. Thermisches Neutronenfeld A.2.1. Teilchenflussdichten A.3. Photonenfeld A.3.1. Teilchenflussdichten der Photonen mit den Energien 511 keV, 2,2 MeV und 4,4 MeV A.3.2. Umgebungs-Äquivalentdosisleistungen A.3.3. Richtungs-Äquivalentdosisleistungen B. Zwischenergebnisse B.1. Quantifizierung des schnellen Neutronenfeldes B.1.1. Pulsladungshistogramme des Stilbendetektors für n₁-Neutronen B.1.2. Anzahlen der Rückstoßprotonen B.2. Quantifizierung des Photonenfeldes B.2.1. Simulierte und gemessene Größen zur Bestimmung der Teilchenflussdichten der Photonen mit den Energien 511 keV, 2,2 MeV und 4,4 MeV / An americium-beryllium source shielded with polyethylene was quantified in regards to its fast and thermal neutron field, as well as its photon field via measurements and simulations. Therefore, radiation field quantities like spectral fluence rates, fluence rates, ambient dose rate equivalents and directional dose rate equivalents of the respective fields were determined in different distances from the radiation source. The produced results will be used for establishing a new irradiation workbench as reference field for neutrons and photons.:Einleitung 1. Theoretische Grundlagen 1.1. Strahlungsfeldgrößen 1.1.1. Radiometrische Größen 1.1.2. Interaktionskoeffizienten 1.1.3. Dosimetrische Größen 1.1.4. Fluenz-zu-Dosis-Konversionskoeffizienten 1.2. Photonen 1.2.1. Wechselwirkung mit Materie 1.2.2. Nachweis durch Szintillationsdetektoren 1.3. Neutronen 1.3.1. Klassifizierung 1.3.2. Wechselwirkung mit Materie 1.3.3. Nachweis schneller Neutronen durch organische Szintillationsdetektoren 1.3.4. Nachweis thermischer Neutronen durch ³He-Zählrohre 1.4. Americium-Beryllium-Quellen 1.4.1. Neutronenerzeugung 1.4.2. Abschirmung 1.5. Detektoren 1.5.1. Szintillationsdetektoren 1.5.2. ³He-Zählrohre 1.6. Digitale Pulsverarbeitung 1.6.1. Pulsformdiskriminierung mit organischen Szintillationsdetektoren 1.7. Monte-Carlo-Strahlungstransportsimulationen 2. Geräte und Materialien 3. Methoden 3.1. Quantifizierung des schnellen Neutronenfeldes 3.1.1. PFD-unterstützte Flugzeitmethode 3.1.2. Einfache Entfaltungstechnik 3.2. Quantifizierung des thermischen Neutronenfeldes 3.3. Quantifizierung des Photonenfeldes 4. Messungen 4.1. Messung 1 4.2. Messung 2 4.3. Messung 3 4.4. Messung 4 4.5. Messung 5 4.6. Messung 6 4.7. Messung 7 4.8. Messung 8 4.9. Messung 9 4.10. Messung 10 5. Simulationen mit FLUKA 5.1. Nachmodellierung der Versuchsaufbauten 5.2. Nachbildung der Strahlungsfelder 5.2.1. Bestimmung der Korrekturfaktoren 5.3. Simulierte Größen 6. Ergebnisse 6.1. Quantifizierung des schnellen Neutronenfeldes 6.1.1. Strahlungsfeldgrößen mittels des Stilbendetektors 6.1.2. Strahlungsfeldgrößen mittels der Plausibilitätsmessungen 6.1.3. Strahlungsfeldgrößen mittels der FLUKA-Simulationen 6.2. Quantifizierung des thermischen Neutronenfeldes 6.2.1. Strahlungsfeldgrößen mittels des ³He-Zählrohrs 6.2.2. Strahlungsfeldgrößen mittels der FLUKA-Simulationen 6.3. Quantifizierung des Photonenfeldes 6.3.1. Strahlungsfeldgrößen mittels des CeBr₃-Detektors 6.3.2. Strahlungsfeldgrößen mittels der Plausibilitätsmessungen 6.3.3. Strahlungsfeldgrößen mittels der FLUKA-Simulationen 7. Diskussion 7.1. Quantifizierung des schnellen Neutronenfeldes 7.1.1. Spektrale Teilchenflussdichten 7.1.2. Umgebungs-Äquivalentdosisleistungen 7.2. Quantifizierung des thermischen Neutronenfeldes 7.2.1. Teilchenflussdichten 7.3. Quantifizierung des Photonenfeldes 7.3.1. Teilchenflussdichten der Photonen mit den Energien 511 keV, 2,2 MeV und 4,4 MeV 7.3.2. Umgebungs-Äquivalentdosisleistungen 7.3.3. Richtungs-Äquivalentdosisleistungen 8. Zusammenfassung A. Bestimmte Strahlungsfeldgrößen A.1. Schnelles Neutronenfeld A.1.1. Spektrale Teilchenflussdichten A.1.2. Umgebungs-Äquivalentdosisleistungen A.2. Thermisches Neutronenfeld A.2.1. Teilchenflussdichten A.3. Photonenfeld A.3.1. Teilchenflussdichten der Photonen mit den Energien 511 keV, 2,2 MeV und 4,4 MeV A.3.2. Umgebungs-Äquivalentdosisleistungen A.3.3. Richtungs-Äquivalentdosisleistungen B. Zwischenergebnisse B.1. Quantifizierung des schnellen Neutronenfeldes B.1.1. Pulsladungshistogramme des Stilbendetektors für n₁-Neutronen B.1.2. Anzahlen der Rückstoßprotonen B.2. Quantifizierung des Photonenfeldes B.2.1. Simulierte und gemessene Größen zur Bestimmung der Teilchenflussdichten der Photonen mit den Energien 511 keV, 2,2 MeV und 4,4 MeV

The aim of this thesis was to investigate the use of effect sizes to report the results of statistical credit rating models in a more practical way. Rating systems in the form of statistical probability models like logistic regression models are used to forecast the behaviour of clients and guide business in rating clients as “high” or “low” risk borrowers. Therefore, model results were reported in terms of statistical significance as well as business language (practical significance), which business experts can understand and interpret. In this thesis, statistical results were expressed as effect sizes like Cohen‟s d that puts the results into standardised and measurable units, which can be reported practically. These effect sizes indicated strength of correlations between variables, contribution of variables to the odds of defaulting, the overall goodness-of-fit of the models and the models‟ discriminating ability between high and low risk customers. / Statistics / M. Sc. (Statistics)

This thesis focuses on the emergence of the teenaged consumer as a market segment in Canada during the 1930s, 1940s, and 1950s. It challenges the notion that teenagers were of little interest to retailers until economics and demographics shaped the more numerous and prosperous post-war teenagers of the Baby Boom generation. Using evidence from corporate records and analysis of mail order catalogues, the study examines how department store retailer, the T. Eaton Company, Limited, began to cultivate a distinct and lucrative teenaged consumer in the 1930s, and thereby began shaping the teenaged consumer. The thesis contextualizes the case study of Eaton’s by exploring the varied expectations that adults had of young people at the time, using census records and magazines (Chatelaine, Canadian Home Journal and Mayfair) to explore concerns about young people’s transition to adulthood. It then focuses on how Eaton’s made a concerted and sustained effort to attract teenager customers to its catalogue and stores. Analysis of its semi-annual catalogue highlights the emergence of specialized clothing size ranges and styles, revealing that Eaton’s increasingly viewed the teenaged years as an important in-between life stage. Eaton’s also instituted teenage advisory councils to both glean market trends and provide a venue for what it considered education for novice consumers. Eaton’s presented consumption as a way to prepare young people for adult roles, legitimizing teenaged participation in the consumer marketplace and contributing to wider debates about when and how teenaged Canadians should reach maturity.

L’implémentation d’une étude d’événement est confrontée à des choix méthodologiques plus ou moins arbitraires concernant la période de l’étude et l’échantillon sélectionné. Or, ces choix méthodologiques conditionnent les résultats obtenus, aboutissant à des divergences notoires en matière de conclusions. Une démarche par simulations, effectuées sur des données réelles de la Bourse de Tunis, nous a permis de juger de la validité des différentes méthodes à utiliser et des différents tests à mettre en œuvre, puis de déterminer celles et ceux qui sont recommandés en fonction des caractéristiques de l’événement à étudier. Nos résultats sont spécifiquement adaptés aux marchés émergents, souffrant d’un manque de liquidité, d’un manque de transparence…En application des résultats de la méthodologie recommandée, nous avons cherché à analyser l’impact sur le marché boursier tunisien, de changements d’abord microstructurels et ensuite environnementaux de nature institutionnelle. Au plan de la microstructure, les choix organisationnels ont été répartis en trois catégories distinctes : la structure du marché, la transparence et le contrôle de la variation des prix. Au plan institutionnel, nous avons axé notre analyse sur l’infrastructure légale en considérant quatre composantes : la protection des investisseurs externes à l’entreprise, les lois sur les valeurs mobilières, les transactions des initiés et le cadre comptable. / Event studies implementation faces many arbitrary methodological choices concerning the period of the study and the selected sample. Unfortunately, these methodological choices condition the results of the study, leading to important differences in the outcomes. An approach by simulations, carried out on actual data of the Tunis stock exchange, has allowed us to judge the validity of the different methods used and the different tests to be implemented, in order to determine those recommended according to the characteristics of the event being studied. Our results are specifically adapted to the emerging markets, known for their lack of liquidity, lack of transparency…Pursuant to the results of the recommended methodology, we next analyze the impact on the Tunisian stock market, of some micro-structural and institutional changes that have occurred in the last years. In terms of microstructure, we precisely examine the structure of the market, its degree of transparency and the mechanisms of price variations control. In terms of institutional environment, we focus our analysis on the legal infrastructure through the aspects of company’s outsiders’ protection, securities law, insiders’ transactions and accounting framework.

The effects of metastable tetragonal zirconia on the properties of Ordinary Portland Cement were observed during which the effect of crystallite size pH on the preparation solution, precursor salt, and the presence of co-precipitates, Fe(OH)3, SnO2 and SiO2 on the crystallization temperature, enthalpy and crystal structure, immediately following the crystallization exothermic burst phenomenon in ZrO2 were measured. Thermal analysis and x-ray methods were used to determine crystallite sizes and structures immediately following the exothermic burst. Comparisons were made for zirconias prepared from oxychloride, chloride and nitrate solutions. The existence of tetrameric hydroxidecontaining ions in oxychloride precursor is used to rationalise low values of crystallization enthalpy. The position of the crystallization temperature, Tmax was not dependent on crystallite size alone but also on the pH at which the gel was made, the surface pH after washing, and the presence of diluent oxides. Enthalpy v r1/2 and Tmax v (diluent vol)1/3 relationships indicate that surface coverage effects dominate a surface nucleated phenomenon. The data established for ZrO2 systems was used to develop tetragonal-ZrO2-SnO2 powders capable of improving the mechanical properties of Ordinary Portland Cement discs. The ZrO2-OPC discs were prepared by powder mixing, water hydration and uniaxial pressing. Vicat needle tests showed that tetragonal-ZrO2 increases the initial setting rate. Microscopy indicated that porosity distribution changes near to ZrO2 particles. Zirconia has also been introduced into OPC discs by vacuum infiltration methods developed for solutions and colloidal suspensions. Comparisons between OPC discs and the OPCtetragonal ZrO2 composites have been made on the basis of diametral compression strength, Young’s modulus, hardness and toughness (K1c), as estimated by the cracked indentation method. Bell-shaped curves are found for the way the mechanical properties are changed as a function of Zirconia content.

<p>The problem under consideration is an unconstrained mini-mization problem in noisy environment. The common approach for solving the problem is Stochastic Approximation (SA) algorithm. We propose a class of adaptive step size schemes for the SA algorithm. The step size selection in the proposed schemes is based on the objective functionvalues. At each iterate, interval estimates of the optimal function&nbsp; value are constructed using the xed number of previously observed function values.&nbsp;If the observed function value in the current iterate is larger than the upper bound of the interval, we reject the current iterate. If the observed function value in the current iterate is smaller than the lower bound of the interval, we suggest a larger step size in the next iterate. Otherwise, if the function value lies in the interval, we propose a small safe step size in the next iterate. In this manner, a faster progress of the algorithm is ensured&nbsp;when it is expected that larger steps will improve the performance of the algorithm. We propose two main schemes which dier in the intervals that we construct at each iterate. In the rst scheme, we construct a symmetrical interval that can be viewed as a condence-like interval for the optimal function value. The bounds of the interval are shifted means of the xed number of previously observed function values. The generalization&nbsp;of this scheme using a convex combination instead of the mean is also presented. In the second scheme, we use the minimum and the maximum of previous noisy function values as the lower and upper bounds of the interval, respectively. The step size sequences generated by the proposed schemes satisfy the step size convergence conditions for the SA algorithm almost surely. Performance of SA algorithms with the new step size schemes is tested on a set of standard test problems. Numerical results&nbsp;support theoretical expectations and verify eciency of the algorithms in comparison to other relevant modications of SA algorithms. Application of the algorithms in LASSO regression models is also considered. The algorithms are applied for estimation of the regression parameters where the objective function contains L₁ penalty.</p> / <p>Predmet istraživanja doktorske disertacije su numerički postupci za re&scaron;avanje problema stohastičke optimizacije. Najpoznatiji numerički postupak za re&scaron;avanje pomenutog problema je algoritam stohastičke aproksimacije (SA). U disertaciji se&nbsp;&nbsp; predlaže nova klasa &scaron;ema za prilagođavanje dužina koraka u svakoj iteraciji. Odabir dužina koraka u predloženim &scaron;emama se zasniva na vrednostima funkcije cilja. U svakoj iteraciji formira se intervalna ocena optimalne vrednosti funkcije cilja koristeći samo registrovane vrednosti funkcije cilja iz ksnog broja prethodnih iteracija. Ukoliko je vrednost funkcije cilja u trenutnoj iteraciji veća od gornje granice intervala, iteracija se odbacuje. Korak dužine 0 se koristi u narednoj iteraciji. Ako je trenutna vrednost funkcije cilja manja od donje granice intervala, predlaže se duži korak u narednoj iteraciji. Ukoliko vrednost funkcije leži u intervalu, u narednoj iteraciji se koristi korak dobijen harmonijskim pravilom. Na ovaj način se obezbeđuje brzi progres algoritma i&nbsp; izbegavaju mali koraci posebno kada se povećava broj iteracija.&nbsp; &Scaron;eme izbegavaju korake proporcionalne sa 1/k kada se očekuje da ce duži koraci pobolj&scaron;ati proces optimizacije. Predložene &scaron;eme se razlikuju u intervalima koji se formiraju u svakoj iteraciji. U prvoj predloženoj &scaron;emi se formira ve&scaron;tački interval poverenja za ocenu optimalne vrednosti funkcije cilja u svakoj iteraciji. Granice tog intervala se uzimaju za&nbsp; kriterijume dovoljnog smanjenja ili rasta funkcije cilja. Predlaže se i uop&scaron;tenje ove &scaron;eme tako &scaron;to se umesto srednje vrednosti koristi konveksna kombinacija prethodnih vrednosti funkcije cilja. U drugoj &scaron;emi, kriterijum po kom se prilagođavaju dužine koraka su minimum i maksimum prethodnih registrovanih vrednosti funkcije cilja. Nizovi koji se formiranju predloženim &scaron;emama zadovoljavaju uslove potrebne za konvergenciju SA algoritma skoro sigurno. SA algoritmi sa novim &scaron;emama za prilagođavanje dužina koraka su testirani na standardnim test&nbsp; problemima i upoređ eni sa SA algoritmom i njegovim postojećim modikacijama. Rezultati pokazuju napredak u odnosu na klasičan algoritam stohastičke aproksimacije sa determinističkim nizom dužine koraka kao i postojećim adaptivnim algoritmima. Takođe se razmatra primena novih algoritama na LASSO regresijske modele. Algoritmi su primenjeni za ocenjivanje parametara modela.</p>

The aim of this thesis was to investigate the use of effect sizes to report the results of statistical credit rating models in a more practical way. Rating systems in the form of statistical probability models like logistic regression models are used to forecast the behaviour of clients and guide business in rating clients as “high” or “low” risk borrowers. Therefore, model results were reported in terms of statistical significance as well as business language (practical significance), which business experts can understand and interpret. In this thesis, statistical results were expressed as effect sizes like Cohen‟s d that puts the results into standardised and measurable units, which can be reported practically. These effect sizes indicated strength of correlations between variables, contribution of variables to the odds of defaulting, the overall goodness-of-fit of the models and the models‟ discriminating ability between high and low risk customers. / Statistics / M. Sc. (Statistics)

This thesis focuses on the emergence of the teenaged consumer as a market segment in Canada during the 1930s, 1940s, and 1950s. It challenges the notion that teenagers were of little interest to retailers until economics and demographics shaped the more numerous and prosperous post-war teenagers of the Baby Boom generation. Using evidence from corporate records and analysis of mail order catalogues, the study examines how department store retailer, the T. Eaton Company, Limited, began to cultivate a distinct and lucrative teenaged consumer in the 1930s, and thereby began shaping the teenaged consumer. The thesis contextualizes the case study of Eaton’s by exploring the varied expectations that adults had of young people at the time, using census records and magazines (Chatelaine, Canadian Home Journal and Mayfair) to explore concerns about young people’s transition to adulthood. It then focuses on how Eaton’s made a concerted and sustained effort to attract teenager customers to its catalogue and stores. Analysis of its semi-annual catalogue highlights the emergence of specialized clothing size ranges and styles, revealing that Eaton’s increasingly viewed the teenaged years as an important in-between life stage. Eaton’s also instituted teenage advisory councils to both glean market trends and provide a venue for what it considered education for novice consumers. Eaton’s presented consumption as a way to prepare young people for adult roles, legitimizing teenaged participation in the consumer marketplace and contributing to wider debates about when and how teenaged Canadians should reach maturity.

No description available.

The making and breaking power of leadership has never been disputable. It is believed to be the single most important factor by which organizations used to exploit opportunities and survive hardships. Despite the fact that all functional areas are not immune to the consequences of good and bad leadership, marketing is uniquely sensitive. Unarguably, all leadership styles are not expected to equally impact marketing performance. A leader of character who inspires followers, helps employees to use their potentials, allows employees to make and fix errors, and pave ways for employee advancement is a one typically needed by organizations. This kind of leader is even more critical for those organizations operating in a brutally competitive market; like the brewing one in Ethiopia. This study is designed to investigate the direct and indirect impact of Transformational Leadership on marketing performance. Moreover, the moderating effect of leaders’ experience and the impact of group difference in leaders’ gender, leaders position and brewery sizes are studied. The unit of analysis are managers and decision makers (committee members) from the four sample breweries (St. George Brewery, Meta Abo Brewery, Raya Brewery, and Habesha Brewery). The data are collected from 211 respondents. In the study, in addition to the data cleaning procedures, all the multivariate data analysis assumptions are ensured. A model is developed and tested using a survey methodology. Four properly validated instruments, one selfdesigned (for marketing performance construct) and three adopted (for transformational leadership, organizational learning, and customer orientation constructs) are used. The validation work is ensured through factor analysis (exploratory and confirmatory). Exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) are worked out using SPSS 21 and AMOS 21 packages respectively. Data is analysed through the structural equation modelling technique. Results show that, Transformational Leadership style is positively and significantly associated with marketing performance, organizational learning and customer orientation. Moreover, it is found that Transformational Leadership indirectly and positively impacts marketing performance. Nevertheless, the hypothesized moderation effect of experience for the impacts of Transformational Leadership on customer orientation is failed to be significant. The study contributes a lot by narrowing the wide literature gap existed in the topic area in the context of the developing world. Secondary evidences are strongly discussed on the antecedents and outcomes of Transformational Leadership and marketing performance. Thus, it is the researcher’s belief that now because of this study; value is added to the body of knowledge and the study can benefit practitioners and academicians alike. / Business Management / D.B.L.