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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.
61

Psychometric evaluation of a leadership empowerment questionnaire in selected organisations in South Africa / Desiree Zikalala

Zikalala, Senzekile Nompumelelo Desiree January 2015 (has links)
The world of work has become extremely volatile, with the scarcity of skills and the management of human capital at the top of the agenda. Human capital is the most valuable asset in any organisation. It is evident that leadership is vital in organisations in ensuring their success; thus making leadership empowerment behaviour crucial. It is essential that our leaders become people developers who focus on growing and up skilling subordinates as a way of attracting and retaining talent. It is important that leaders create an enabling environment for their subordinates; one of independence, innovation and, more importantly, growth and development. The purpose of this study was to explore the psychometric properties of the leadership empowerment questionnaire by investigating internal consistency; furthermore investigating the differences between genders regarding male and female perceptions of leadership empowerment behaviour. A quantitative cross-sectional survey was used. The measuring battery comprised the Leadership Empowerment Behaviour Questionnaire (LEBQ), which is originally a six-factor structure. The analysis was carried out using the IBM-SPSS and Mplus statistical modelling programs. Reliability was explored by utilising the Confirmatory Factor Analysis (CFA) index (rho). Construct validity was assessed by examining the factor structure, utilising the Exploratory Factor Analysis (EFA) and the CFA. Satisfactory reliability indices were attained. A three-factor model of the LEBQ was confirmed. The three-factor model consists of autonomy, development and accountability. Measurement invariance was tested by the use of configural, scalar and metric invariance. The configural model concluded that the three-factor structure obtained for the total sample also holds for the two groups (Males & Females) of respondents separately. The metric model indicates that the latent variables are measured in the same way with the same metric in the two target groups. The Scalar model indicates that on these three items, males and females differ regarding their starting points in their response to these questions. Although there were differences in the starting points of certain items, there were no real differences evident in the overall model regarding males and females. Recommendations for further research were made. / MA (Industrial Psychology)--North-West University, Vaal Triangle Campus, 2015
62

Psychometric evaluation of a leadership empowerment questionnaire in selected organisations in South Africa / Desiree Zikalala

Zikalala, Senzekile Nompumelelo Desiree January 2015 (has links)
The world of work has become extremely volatile, with the scarcity of skills and the management of human capital at the top of the agenda. Human capital is the most valuable asset in any organisation. It is evident that leadership is vital in organisations in ensuring their success; thus making leadership empowerment behaviour crucial. It is essential that our leaders become people developers who focus on growing and up skilling subordinates as a way of attracting and retaining talent. It is important that leaders create an enabling environment for their subordinates; one of independence, innovation and, more importantly, growth and development. The purpose of this study was to explore the psychometric properties of the leadership empowerment questionnaire by investigating internal consistency; furthermore investigating the differences between genders regarding male and female perceptions of leadership empowerment behaviour. A quantitative cross-sectional survey was used. The measuring battery comprised the Leadership Empowerment Behaviour Questionnaire (LEBQ), which is originally a six-factor structure. The analysis was carried out using the IBM-SPSS and Mplus statistical modelling programs. Reliability was explored by utilising the Confirmatory Factor Analysis (CFA) index (rho). Construct validity was assessed by examining the factor structure, utilising the Exploratory Factor Analysis (EFA) and the CFA. Satisfactory reliability indices were attained. A three-factor model of the LEBQ was confirmed. The three-factor model consists of autonomy, development and accountability. Measurement invariance was tested by the use of configural, scalar and metric invariance. The configural model concluded that the three-factor structure obtained for the total sample also holds for the two groups (Males & Females) of respondents separately. The metric model indicates that the latent variables are measured in the same way with the same metric in the two target groups. The Scalar model indicates that on these three items, males and females differ regarding their starting points in their response to these questions. Although there were differences in the starting points of certain items, there were no real differences evident in the overall model regarding males and females. Recommendations for further research were made. / MA (Industrial Psychology)--North-West University, Vaal Triangle Campus, 2015
63

Topics in portfolio choice : qualitative properties, time consistency and investment under model uncertainty

Kallblad, Sigrid Linnea January 2014 (has links)
The study of expected utility maximization in continuous-time stochastic market models dates back to the seminal work of Merton 1969 and has since been central to the area of Mathematical Finance. The associated stochastic optimization problems have been extensively studied. The problem formulation relies on two strong underlying assumptions: the ability to specify the underpinning market model and the knowledge of the investor's risk preferences. However, neither of these inputs is easily available, if at all. Resulting issues have attracted continuous attention and prompted very active and diverse lines of research. This thesis seeks to contribute towards this literature and questions related to both of the above issues are studied. Specifically, we study the implications of certain qualitative properties of the utility function; we introduce, and study various aspects of, the notion of robust forward investment criteria; and we study the investment problem associated with risk- and ambiguity-averse preference criteria defined in terms of quasiconcave utility functionals.
64

Improving data quality : data consistency, deduplication, currency and accuracy

Yu, Wenyuan January 2013 (has links)
Data quality is one of the key problems in data management. An unprecedented amount of data has been accumulated and has become a valuable asset of an organization. The value of the data relies greatly on its quality. However, data is often dirty in real life. It may be inconsistent, duplicated, stale, inaccurate or incomplete, which can reduce its usability and increase the cost of businesses. Consequently the need for improving data quality arises, which comprises of five central issues of improving data quality, namely, data consistency, data deduplication, data currency, data accuracy and information completeness. This thesis presents the results of our work on the first four issues with regards to data consistency, deduplication, currency and accuracy. The first part of the thesis investigates incremental verifications of data consistencies in distributed data. Given a distributed database D, a set S of conditional functional dependencies (CFDs), the set V of violations of the CFDs in D, and updates ΔD to D, it is to find, with minimum data shipment, changes ΔV to V in response to ΔD. Although the problems are intractable, we show that they are bounded: there exist algorithms to detect errors such that their computational cost and data shipment are both linear in the size of ΔD and ΔV, independent of the size of the database D. Such incremental algorithms are provided for both vertically and horizontally partitioned data, and we show that the algorithms are optimal. The second part of the thesis studies the interaction between record matching and data repairing. Record matching, the main technique underlying data deduplication, aims to identify tuples that refer to the same real-world object, and repairing is to make a database consistent by fixing errors in the data using constraints. These are treated as separate processes in most data cleaning systems, based on heuristic solutions. However, our studies show that repairing can effectively help us identify matches, and vice versa. To capture the interaction, a uniform framework that seamlessly unifies repairing and matching operations is proposed to clean a database based on integrity constraints, matching rules and master data. The third part of the thesis presents our study of finding certain fixes that are absolutely correct for data repairing. Data repairing methods based on integrity constraints are normally heuristic, and they may not find certain fixes. Worse still, they may even introduce new errors when attempting to repair the data, which may not work well when repairing critical data such as medical records, in which a seemingly minor error often has disastrous consequences. We propose a framework and an algorithm to find certain fixes, based on master data, a class of editing rules and user interactions. A prototype system is also developed. The fourth part of the thesis introduces inferring data currency and consistency for conflict resolution, where data currency aims to identify the current values of entities, and conflict resolution is to combine tuples that pertain to the same real-world entity into a single tuple and resolve conflicts, which is also an important issue for data deduplication. We show that data currency and consistency help each other in resolving conflicts. We study a number of associated fundamental problems, and develop an approach for conflict resolution by inferring data currency and consistency. The last part of the thesis reports our study of data accuracy on the longstanding relative accuracy problem which is to determine, given tuples t1 and t2 that refer to the same entity e, whether t1[A] is more accurate than t2[A], i.e., t1[A] is closer to the true value of the A attribute of e than t2[A]. We introduce a class of accuracy rules and an inference system with a chase procedure to deduce relative accuracy, and the related fundamental problems are studied. We also propose a framework and algorithms for inferring accurate values with users’ interaction.
65

Reliable Writeback for Client-side Flash Caches

Qin, Dai 04 July 2014 (has links)
Modern data centers are increasingly using shared storage solutions for ease of management. Data is cached on the client side on inexpensive and high-capacity flash devices, helping improve performance and reduce contention on the storage side. Currently, write-through caching is used because it ensures consistency and durability under client failures, but it offers poor performance for write-heavy workloads. In this work, we propose two write-back based caching policies, called write-back flush and write-back persist, that provide strong reliability guarantees, under two different client failure models. These policies rely on storage applications such as file systems and databases issuing write barriers to persist their data, because these barriers are the only reliable method for storing data durably on storage media. Our evaluation shows that these policies achieve performance close to write-back caching, while providing stronger guarantees than vanilla write-though caching.
66

Sexual selection and personality in zebra finches, Taeniopygia guttata

Schuett, Wiebke January 2008 (has links)
Despite recent increasing interest in the existence of animal personality, i.e. intra-individual consistency and inter-individual variation in the level of a behavioural trait, the evolutionary (and ecological) consequences of these consistent behavioural differences remain poorly understood. Some recent studies have revealed that variation in animal personalities might be linked to competitive interactions, resulting from natural selection. However, since personalities might similarly affect mate acquisition and reproductive success, it seems crucial to also explore their evolution under the framework of sexual selection theory. In this thesis I investigate the influence of personality on mate choice, reproductive success, female-male and male-male interactions, using zebra finches, Taeniopygia guttata, as a model species. After (I) I review the few existing studies assessing the link between sexual selection and personality, I propose a framework on the relationship between sexual selection and personality. Subsequently, (II) I show with different experimental approaches for the first time that (a) females choose males on the basis of their behaviour per se (male behaviour was experimentally disentangled from any appearance effects) whilst considering their own personality in their choice: less exploratory females did not distinguish between exploratory and non-exploratory appearing males, whereas moderately and highly exploratory females preferred similar males. (b) These preferences have an adaptive value to the exploratory females: exploratory females which had a behaviourally similar partner raised chicks in best condition but chicks in worst condition if they had a dissimilar partner. Low exploration females always raised chicks in intermediate condition, which may explain why they did not choose males on the basis of their exploratory behaviour. (c) I provide evidence that the combination of personalities in a pair, not only in terms of the level of the behaviour but also in terms of the behavioural consistency, influence reproductive success. However, this was only true for foster but not genetic parents, suggesting that behavioural rather than genetic compatibility (for the measured personality traits) is important for reproduction. (d) Moreover, some male behavioural characteristics appear to be a signal of male quality: highly exploratory foster males raised chicks (both males and females) in best condition, which themselves raised foster chicks of increased conditions. (e) Furthermore, a number of sex differences in personality traits (both level and consistency) are identified, including different responses to social interactions. (f) Additionally, I show how females with different exploratory tendencies differ in their movement patterns during mate choice. (g) Finally, I demonstrate that in competitive male-male situations, a measurement of condition, the fat score, and aggressive behaviour are positively correlated. These findings are set into sexual selection context (but other evolutionary processes are also considered) and both their ecological and evolutionary consequences are discussed. I outline how these results make a valuable contribution to the research field and discuss their potential to indicate new directions for future studies.
67

The Effects of Interresponse Intervals on Behavioral Variability in Humans

Reilly, Mark P. (Mark Peter) 12 1900 (has links)
The present experiment studied the relationship between interresponse intervals and behavioral variability. Subjects emitted sequences of 4 keypresses on two keys on a variability schedule that delivered points when the current 4-response sequence differed from the previous 5 sequences. Three experimental conditions were studied; no interresponse interval, 4-s interresponse interval and 8-s interresponse interval. Interresponse intervals followed each of the first three responses in each sequence. Two groups were used to study initial training histories. Group 1 was first exposed to the no-interresponse interval condition. Group 2 was first exposed to the 4-s interresponse interval condition. Subjects were then exposed to the different interresponse interval conditions. There was little change in variability across conditions. However, the variability observed in the subjects first exposed to the 4-s interresponse interval was greater than the variability observed in subjects first exposed to no-interresponse interval. There was higher-order response patterning in both groups, but it was more pronounced in the no-interresponse interval group.
68

Model checking in Tobit regression model via nonparametric smoothing

Liu, Shan January 1900 (has links)
Master of Science / Department of Statistics / Weixing Song / A nonparametric lack-of-fit test is proposed to check the adequacy of the presumed parametric form for the regression function in Tobit regression models by applying Zheng's device with weighted residuals. It is shown that testing the null hypothesis for the standard Tobit regression models is equivalent to test a new null hypothesis of the classic regression models. An optimal weight function is identified to maximize the local power of the test. The test statistic proposed is shown to be asymptotically normal under null hypothesis, consistent against some fixed alternatives, and has nontrivial power for some local nonparametric power for some local nonparametric alternatives. The finite sample performance of the proposed test is assessed by Monte-Carlo simulations. An empirical study is conducted based on the data of University of Michigan Panel Study of Income Dynamics for the year 1975.
69

Processos gráficos e a NBR 15936-1: avaliação da consistência colorimétrica / Graphics and processes NBR 15936-1: evaluation colorimetric consistency

Mortara, Bruno Arruda 09 June 2015 (has links)
Este estudo abrange as bases teóricas, com ênfase maior nos temas afins à colorimetria, dos requisitos da NBR 15936-1, de 2011, criada pela ABNT/ONS-027 Tecnologia Gráfica. A norma tem como objetivo \"...especifica[r] os requisitos para um provedor que seja capaz de produzir impressos a partir de arquivos digitais padronizados, simulando uma condição de impressão pública e aceita em todo o mundo, dentro das tolerâncias especificadas nesta Norma...e aplica-se aos processos de recepção de arquivos digitais, execução de provas digitais e processos de impressão / Thisstudycovered the theoreticalconcepts, withemphasisonthoserelatedto colorimetry, involving the requirements of NBR 15936-1, from 2011, with tile \"Graphictechnology - Quality in reproductionprocessPart 1: Requirements\", published by ABNT/ONS-027 - Graphic Technology. The standard aimsto \"specify ... the requirements for a providerthat is capable of producingstandardizedprintedfrom digital files, simulating a publicprintingcondition, accepted world wide, within the tolerancesspecified in this standard and...appliesto the processes of receiving digital files, implementation of digital proofsandprintingwithor web offset processes.\"
70

Influence des facteurs non syntaxiques sur l'accord en nombre : approche développementale / Influence of non syntactic factors in number agreement : developmental approach

Lusson, Charlotte 14 October 2013 (has links)
Cette thèse examine l'influence qu'exercent certaines caractéristiques de l'élément à accorder sur les performances de rédacteurs francophones, novices et experts, dans différentes tâches de traitement de l'accord en nombre. Une première série d'expériences teste l'impact de la présence d'informations morpho-phonologiques et conceptuelles portées par le verbe. Les résultats montrent qu'à partir du CM2, une terminaison verbale phonologiquement distincte entre le singulier et le pluriel améliore le traitement de l'accord La présence d'une information conceptuelle au niveau du verbe conduit en revanche les participants, dès le CMl, à commettre davantage d'erreurs d'accord. Le traitement d'un verbe dont l'action est nécessairement accomplie par plusieurs agents semble engendrer des perturbations au moment de l'accord. Les informations morpho-phonologiques et conceptuelles influencent également les durées de la production de phrases dictées et le nombre d'erreurs d'accord correctement détectées dans une tâche de révision. Une seconde série d'expériences analyse I'impact du coût attentionnel engendré par la complexité de la gestion de l'orthographe lexicale sur le traitement de l'accord, en manipulant la fréquence lexicale et la consistance orthographique. L'effet de ces variables sur les eneurs commises par les enfants suggère que la probabilité d'accorder en nombre varie en fonction de la fréquence (facteur lexical) et de la consistance (facteur ous-lexical) des mots et ce, du CEI au CM2. Dans l'ensemble, les résultats de cette thèse suggèrent que I'accord n'est pas traité indépendamment de certaines caractéristiques propres à l'élément à accorder. / This thesis examines the influence of some characteristics of the agreement target on the performances of novice and expert writers in number agreement via different tasks. A first series of experiments studies the impact of the presence of morpho-phonological and conceptual information carried by the verb. Results show that from the 5th grade, aphonologically distinct verbal ending between singular and plural improves agreement processing. The presence of a conceptual information on the verb leads however participants from the 4th grade to commit more agreement errors. The processing of a verb whose action is necessarily accomplished by several agents seems to create disturbances during theagreement. Morpho- phonological and conceptual information also influence the duration of production of dictated sentences and the number of agreement errors correctly detected in revision tasks. A second series of experiments analyzes the impact of cognitive cost incurred by the complexity of the management of lexical spelling on the treatment of agreement, by manipulating lexical frequency and orthographic consistency. The effect of these variables on the errors committed by children suggests that the probability of agreement in number varies with frequency (lexical factor) and consistency (sub- lexical factor) and this, from 2nd to 5th grade. Overall, the results of this thesis suggest that agreement is not processed independently from some specific characteristics of the agreement's target

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