Thesis (Ph.D.)--University of Nebraska-Lincoln, 2009. / Title from title screen (site viewed January 5, 2010). PDF text: xii, 190 p. : col. ill. ; 1 Mb. UMI publication number: AAT 3365711. Includes bibliographical references. Also available in microfilm and microfiche formats.

Given the growth and outreach of new information, communication, computing and electronic technologies in various dimensions, the amount of data has explosively increased in the recent years. Centralised systems suffer some limitations to dealing with this issue due to all data is stored in central data centres. Thus, decentralised systems are getting more attention and increasing in popularity. Moreover, efficient service discovery mechanisms have naturally become an essential component in both large-scale and small-scale decentralised systems and. This research study is aimed at modelling a novel efficient indexing and searching model for service discovery in decentralised environments comprising numerous repositories with massive stored services. The main contributions of this research study can be summarised in three components: a novel distributed multilevel indexing model, an optimised searching algorithm and a new simulation environment. Indexing model has been widely used for efficient service discovery. For instance; the inverted index is one of the popular indexing models used for service retrieval in consistent repositories. However, redundancies are inevitable in the inverted index which is significantly time-consuming in the service discovery and retrieval process. This theeis proposes a novel distributed multilevel indexing model (DM-index), which offers an efficient solution for service discovery and retrieval in distributed service repositories comprising massive stored services. The architecture of the proposed indexing model encompasses four hierarchical levels to eliminate redundancy information in service repositories, to narrow the searching space and to reduce the number of traversed services whilst discovering services. Distributed Hash Tables have been widely used to provide data lookup services with logarithmic message costs which only require maintenance of limited amounts of routing states. This thesis develops an optimised searching algorithm, named Double-layer No-redundancy Enhanced Bi-direction Chord (DNEB-Chord), to handle retrieval requests in distributed destination repositories efficiently. This DNEB-Chord algorithm achieves faster routing performances with the double-layer routing mechanism and optimal routing index. The efficiency of the developed indexing and searching model is evaluated through theoretical analysis and experimental evaluation in a newly developed simulation environment, named Distributed Multilevel Bi-direction Simulator (DMBSim), which can be used as cost efficient tool for exploring various service configurations, user retrieval requirements and other parameter settings. Both the theoretical validation and experimental evaluations demonstrate that the service discovery efficiency of the DM-index outperforms the sequential index and inverted index configurations. Furthermore, the experimental evaluation results demostrate that the DNEB-Chord algorithm performs better than the Chord in terms of reducing the incurred hop counts. Finally, simulation results demonstrate that the proposed indexing and searching model can achieve better service discovery performances in large-scale decentralised environments comprising numerous repositories with massive stored services.

This study provides a measurable model of the concept of place vulnerability for HIV/AIDS that incorporates both community and structural level effects using data provided at the ZIP code level from the Texas Department of State Health Services. Sociological literature on the effects of place on health has been growing but falls short of providing an operational definition of the effects of place on health. This dissertation looks to the literature in medical/health geography to supplement sociology’s understanding of the effects of place on health, to the end of providing a measurable model. Prior research that has recognized the complexity of the effects of place still have forced data into one scale and emphasized individual-level outcomes. A multilevel model allows for keeping the associated spatial unit data, without aggregating or parsing it out for convenience of model fit. The place vulnerability model proposed examines how exposure, capacity and potentiality variables all influence an area’s HIV/AIDS count. To capture the effects of place vulnerability at multiple levels, this dissertation research uses a multilevel zero-inflated poisson (MLZIP) model to examine how factors measured at the ZIP code and county both affect HIV/AIDS counts per ZIP code as an outcome. Furthermore, empirical Bayes estimates are mapped to display how well the model fits across the state of Texas. Limitations of this research include the need to incorporate time, more specific predictors, and individual level factors. The methodology developed permits a more thorough understanding of place effects on the spatial variation of HIV/AIDS.

by Kam Suet-Shan, Yu Sik-Ching. / Thesis (M.B.A.)--Chinese University of Hong Kong, 1996. / Includes bibliographical references (leaves 70-72). / ABSTRACT --- p.i / TABLE OF CONTENTS --- p.ii / LIST OF FIGURES --- p.v / LIST OF TABLES --- p.vi / CHAPTER / Chapter I. --- "INTRODUCTION, RELEVANCE AND OVERVIEW" --- p.1 / The Information Technology Industry --- p.1 / How This Paper Structured --- p.3 / Chapter II. --- MULTI-LEVEL MARKETING --- p.5 / Definition of Multi-level Marketing (MLM) --- p.5 / Evolution of Multi-level Marketing in the US --- p.6 / Operation of Multi-level Marketing --- p.8 / Introduction and Sponsoring --- p.8 / Signing with the Company --- p.8 / Retailing the Products --- p.9 / Distributing the Products --- p.9 / Establishing a Network --- p.10 / Realization of Profits and Earnings --- p.10 / Chapter III. --- COMPARISON OF MULTI-LEVEL MARKETING AND TRADITIONAL DISTRIBUTION --- p.12 / Traditional Distribution Channel --- p.12 / The Difference between MLM and Traditional Distribution --- p.13 / Distribution Structure --- p.14 / Relationship with the Company --- p.16 / Selling Target --- p.17 / Relationship with the Customers --- p.17 / Chapter IV. --- MULTI-LEVEL MARKETING IN HONG KONG --- p.18 / Development of Multi-level Marketing in Hong Kong --- p.18 / Multi-level Marketing in Skin-care and Cosmetic Products Retailing --- p.21 / Multi-level Marketing in Health Food Products Retailing --- p.23 / Chapter V. --- EVALUATION OF THE MULTI-LEVEL MARKETING --- p.26 / Characteristics of Products Using MLM --- p.26 / Marketability --- p.26 / Good Quality --- p.27 / Consumable --- p.27 / Mass Market Demand --- p.27 / High Profit Margin --- p.28 / Characteristics of Companies in Hong Kong Using MLM --- p.28 / Restriction of Retail Outlet --- p.29 / Informal Structure --- p.29 / Motivation and Supporting System --- p.29 / Warehousing --- p.30 / Computerized Database Networking --- p.30 / Problems of Multi-level Marketing when Applied in Information Technology Industry --- p.30 / Chapter VI. --- OVERVIEW OF REFERRAL (SINGLE-LEVEL MARKETING) CONCEPT --- p.32 / Application of Referral in Other Industries --- p.33 / Chapter VII. --- RESEARCH METHOD --- p.35 / Research Objectives --- p.35 / Research Design --- p.35 / Cognitive Component --- p.35 / Affective Component --- p.38 / Conative Component --- p.38 / Data Collection --- p.38 / Sampling --- p.39 / Questionnaire Dissection --- p.40 / Q1 - Q2 --- p.40 / Q3-Q4 --- p.40 / Q5- Q7B --- p.41 / Q7C - Q7E --- p.41 / Chapter VIII. --- RESULTS --- p.42 / Demographics --- p.42 / Age --- p.42 / Marital Status --- p.43 / Education Level --- p.43 / Occupation --- p.44 / Monthly Income --- p.44 / Analysis --- p.45 / One-Sample t Tests --- p.45 / Chapter IX. --- LIMITATIONS --- p.51 / Chapter X. --- MARKETING PLAN --- p.53 / Target Customers --- p.54 / Product --- p.54 / Price --- p.57 / Place --- p.57 / Promotion --- p.58 / Get an Initial Set of Customers --- p.59 / Attract Existing Customers to Participate in the Network Marketing (Referral) Program --- p.60 / Encourage Existing Marketers to Refer Others --- p.61 / Chapter XI. --- CONCLUSION --- p.64 / APPENDIX / Chapter I. --- LIST OF MULTI-LEVEL MARKETING COMPANIES REGISTERED IN THE DIRECT SELLING ASSOCIATION OF HONG KONG LTD --- p.66 / Chapter II. --- SAMPLE QUESTIONS --- p.67 / REFERENCES --- p.70 / Books --- p.70 / Periodicals --- p.71

abstract: Measurement invariance exists when a scale functions equivalently across people and is therefore essential for making meaningful group comparisons. Often, measurement invariance is examined with independent and identically distributed data; however, there are times when the participants are clustered within units, creating dependency in the data. Researchers have taken different approaches to address this dependency when studying measurement invariance (e.g., Kim, Kwok, & Yoon, 2012; Ryu, 2014; Kim, Yoon, Wen, Luo, & Kwok, 2015), but there are no comparisons of the various approaches. The purpose of this master's thesis was to investigate measurement invariance in multilevel data when the grouping variable was a level-1 variable using five different approaches. Publicly available data from the Early Childhood Longitudinal Study-Kindergarten Cohort (ECLS-K) was used as an illustrative example. The construct of early behavior, which was made up of four teacher-rated behavior scales, was evaluated for measurement invariance in relation to gender. In the specific case of this illustrative example, the statistical conclusions of the five approaches were in agreement (i.e., the loading of the externalizing item and the intercept of the approaches to learning item were not invariant). Simulation work should be done to investigate in which situations the conclusions of these approaches diverge. / Dissertation/Thesis / Masters Thesis Psychology 2016

Thesis submitted in fulfilment of the requirements for the degree Doctor of Technology: Electrical Engineering in the Faculty of Engineering at the Cape Peninsula University of Technology / This research focuses on the predictive current control of multilevel converters with the aim of providing an optimized system for three-phase, multilevel inverters (MLIs) so that the load current and the voltage of the capacitors can be controlled. A model predictive current control algorithm is proposed, specifically directed at the utilisation of power obtained from renewable energy systems (RESs). The model was developed for three-phase, multilevel voltage source inverters (MLVSIs), three-phase, three-level diode-clamped converters (DCCs) and flying capacitor converters (FCCs). In this study the renewable energy systems model is used to investigate system performance when power is supplied to a resistiveinductive load (RL-load). The proposed control method was split into two different control algorithms. Firstly, a finite set-model predictive current control (FS-MPCC) method was developed to control the output current of three-phase, MLIs. This control method was selected to reduce the calculation effort for model predictive control (MPC) and to increase the possible prediction horizon. Secondly, to solve the flying capacitor voltage balance problem in an FCC, as well as to solve the DC-link capacitor voltage balance problem in a DCC, a hysteresis-voltage alancing algorithm based on predictive control, was designed—this algorithm was used to keep the flying capacitor voltages and DC-link capacitor voltages within their hysteresis bands. Finally, for some classes of power converters, a performance evaluation of the FS-MPCC method for three-phase, three-level MLIs was investigated in terms of power quality and dynamic response. The improvement was assessed in terms of total harmonic distortion (THD) of the output voltage for the RL-load. The modelling and co-simulation were carried out using MATLAB/Simulink with PSIM software. The co-simulation results indicated that the proposed control algorithms achieved both high performance and a high degree of robustness in RESs applications.

The purpose of the study was threefold: (1) to determine the factor structure of mathematical thinking at the within-classroom and at the between-classroom level / (2) to investigate the extent of variation in the relationships among different mathematical thinking constructs at the within- and between-classroom levels / and (3) to examine the cross-level interactions among different types of mathematical thinking. Previous research was extended by investigating the factor structure of mathematical thinking in derivative at the within- and between-classroom levels, and further examining the direct, indirect, and cross-level relations among different types of mathematical thinking. Multilevel analyses of a cross-sectional dataset containing two independent samples of undergraduate students nested within classrooms showed that the within-structure of mathematical thinking includes enactive, iconic, algorithmic, algebraic, formal, and axiomatic thinking, whereas the between-structure contains formal-axiomatic, proceptual-symbolic, and conceptual-embodied thinking. Major findings from the two-level mathematical thinking model revealed that: (1) enactive, iconic, algebraic, and axiomatic thinking varied primarily as a function of formal and algorithmic thinking / (2) the strongest direct effect of formal-axiomatic thinking was on proceptual-symbolic thinking / (3) the nature of the relationships was cyclic at the between-classroom level / (4) the within-classroom mathematical thinking constructs significantly moderate the relationships among conceptual-embodied, proceptual-symbolic, and formal-axiomatic thinking / and (5) the between-classroom mathematical thinking constructs moderate the relationships among enactive, iconic, algorithmic, algebraic, formal, and axiomatic thinking. The challenges when using multilevel exploratory factor analysis, multilevel confirmatory factor analysis, and multilevel structural equation modeling with categorical variables are emphasized. Methodological and educational implications of findings are discussed.

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Much current research on victimisation focuses primarily on demographic risk factors associated with those who have experienced crime and how these factors affect the likelihood of a person breaching the so called ‘first hurdle’. That is, the probability of moving from a state of non-victim to one of victim. In contrast, this thesis will argue that in order to achieve a more comprehensive understanding of victimisation, it is not only desirable but necessary to move beyond the study of the causes of criminal victimisation and examine the consequences for victims as well as the criminal justice system as a whole. Thus, it seeks to explain the experience of victimisation not just as an isolated incident, but as a process consisting of a number of steps or stages of progression through the criminal justice system, each one building on the last. As such, in addition to considering risk factors, this thesis also examines the decision to report a crime to the police, the use of victim services, as well as the perceived satisfaction with services received. In so doing it explores not only the causes and consequences of crime, but the longer term impact of criminal victimisation. The results presented here are based on the secondary analysis of data from the 2008/9 Scottish Crime and Justice Survey complimented by a data set acquired through in-depth interviews with victims of crime from the Edinburgh Local Authority. Interview data is used to provide a greater depth of meaning to the patterns which emerged from the survey data; lending insight into the psychological processes driving victim decision making and behaviour. This thesis thus provides an example of how a combination of techniques including multi-level modelling and interview analysis, provide a clearer understanding of how victims experience crime. Findings suggest that factors associated with each step of the process are related and may represent a more general underlying pattern of victimisation. It is also argued that by employing multi-level analysis, the thesis provides a more accurate explanation of how respondent’s experiences may differ according to the context in which they live. Finally, the analysis highlights the ongoing importance of emotion in victim decision making and the severity of long term impact. The analysis presented offers new insights into how we understand victimisation as an ongoing experience, as well as demonstrating the necessity of the analytic techniques employed. It is however somewhat confined by the coverage of survey questions and the limited generalizability of the data collected in interviews due to the small sample size. These concerns will be discussed, along with recommendations for victim policy and future research.

Thesis advisor: Sara M. Moorman / I examine how preloss relationship quality with a deceased parent and pre- to post-loss change in relationship quality with a surviving parent influence adult children's marital satisfaction over time. I also test gender interactions. Analyses are based on married or cohabiting adults who experienced the death of a parent (N = 316), drawn from the Longitudinal Study of Generations (LSOG), a longitudinal study of three-plus-generation families from Southern California. Three-level multilevel modeling (MLM) techniques reveal that improved relationship quality with a surviving parent is related to improved marital satisfaction. High preloss relationship quality with a deceased mother is related to improved post-loss marital satisfaction only for sons. These results support theories of linked lives and role context, and suggest that sons who lose mothers are particularly vulnerable relationally and may be especially sensitive to perceived support from their wives. / Thesis (MA) — Boston College, 2013. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Sociology.