Factor, structured factor and vine copula models for multivariate social science data

The development of multivariate models with parsimonious dependence is of great interest in a wide range of applications. Two broad frameworks have been considered for parsimonious dependence modelling, namely the latent variable (factor) and copula frameworks. Within these two broad frameworks, we propose several factor models based on copulas for modelling parsimonious dependence structures in multivariate social science data. We develop factor copula models for mixed continuous and discrete responses where the dependence among the observed variables is explained via a few factors. These are conditional independence models; the observed variables are conditionally independent given the factors. We also propose the bi-factor and second-order copula models for item response data that can be split into non-overlapping groups, where each group of items has homogeneous dependence. These proposed models fall under the structured factor copula class. Our general models subsume the Gaussian bi-factor and second-order models as special cases and are suitable for capturing different dependencies between and within different groups of observed variables. Using the vine copula framework, we extend the factor copula models in order to capture any residual dependence. We propose combined factor/truncated vine copula models for item response data. These are conditional dependence models given very few factors. The proposed models can be viewed as a truncated regular vine copula models that involve both observed and latent variables. They allow for flexible construction based on a sequence of bivariate copulas that can provide different tail, asymmetric and non-linear dependence properties. All the proposed copula models are applied to real datasets and are compared with other relevant benchmark models showing substantial improvement and performance both conceptually and in fit to data

Factor tree copula models for item response data

Factor copula models for item response data are more interpretable and fit better than (truncated) vine copula models when dependence can be explained through latent variables, but are not robust to violations of conditional independence. To circumvent these issues, truncated vines and factor copula models for item response data are joined to define a combined model, the so called factor tree copula model, with individual benefits from each of the two approaches. Rather than adding factors and causing computational problems and difficulties in interpretation and identification, a truncated vine structure is assumed on the residuals conditional on one or two latent variables. This structure can be better explained as a conditional dependence given a few interpretable latent variables. On the one hand the parsimonious feature of factor models remains intact and any residual dependencies are being taken into account on the other. We discuss estimation along with model selection. In particular we propose model selection algorithms to choose a plausible factor tree copula model to capture the (residual) dependencies among the item responses. Our general methodology is demonstrated with an extensive simulation study and illustrated by analysing Post Traumatic Stress Disorder

Factor copula models for mixed data

We develop factor copula models to analyse the dependence among mixed continuous and discrete responses. Factor copula models are canonical vine copulas that involve both observed and latent variables, hence they allow tail, asymmetric and nonlinear dependence. They can be explained as conditional independence models with latent variables that do not necessarily have an additive latent structure. We focus on important issues of interest to the social data analyst, such as model selection and goodness of fit. Our general methodology is demonstrated with an extensive simulation study and illustrated by reanalysing three mixed response data sets. Our studies suggest that there can be a substantial improvement over the standard factor model for mixed data and make the argument for moving to factor copula models

TOFHIR2 ASIC Data Transmission VHDL Simulation

This project report describes the work done during an 8-week summer student internship at CERN to create a TOFHIR2 simulator. The project was part of the larger upgrade of the LHC for the high luminosity era and aimed to simulate the data transmission process of the TOFHIR2 ASIC, which is an integral part of the minimum ionizing particle timing detector. The report provides an overview of the TOFHIR2 and its location in the barrel timing layer, as well as the five stages of the TOFHIR2 data transmission process. The project focused on simulating this data transmission process using VHDL. The report shows the VHDL simulation code structure, purpose of each part of the code, and simulation results. Although the simulation code has some limitations, it provides a starting point to create a more comprehensive simulator that could be used to test the actual TOFHIR2 ASIC before making changes. Overall, this project contributes to the ongoing efforts to upgrade the LHC for the high luminosity era

Developing Motivational and Coaching Skills in Telecom Companies. A comparative study between Batelco and Zain, Bahrain

Over the last 20 years, the telecommunication industry has grown rapidly and has become one of the major business markets in the Kingdom of Bahrain. Today it can be considered as the fastest growing segment of trade and business development in the country. Since 2000, monopoly of the telecom market has been demolished as the government has modified the policy of licensing mobile enterprises. This, along with the advanced technology in telecom sector, has led to the launching of numerous competitors to the only telecom company, Batelco, including the fast growing company, Zain, with its comparative facilities and prices. The two major telecom companies; Batelco and Zain, are run and headed by Bahraini and non-Bahraini CEOs. This study is to examine selected issues, which are fundamentally related to management in general and to leadership in particular. The main objective of the study is to explore the domain of motivational and coaching skills within telecom business sector by using empirical analysis. It will explore, first, how leaders make effective use of motivational and coaching skills to improve employees’ performance in both Batelco and Zain; the two major leading companies in telecommunication, mobile services and internet market in Bahrain. Second, it will investigate the impact of leaders’ motivation and coaching techniques on employees. The hypotheses of the study are the following: 1. The motivational and coaching techniques implemented by the two companies in order to enhance performance of customer service representatives are extremely distinctive. 2. From employees’ perception, leaders are motivating to a specific extant in one company and demotivating in another. 3. The motivational techniques in both companies are matching the organisation’s objectives and employees' needs. 4. Managers are found to understand the concepts of a coach or a motivational leader in one company rather than the other. 5. The findings in the empirical part correspond to the theory in the field. The analysis has verified that a statistically significant relationship exists between existing motivational and coaching techniques and skills taken for granted by leaders, and employees’ satisfaction, and subsequently specific degree of performance within the two telecom organisations. The study showed that lower or inappropriate motivation practices at work place were reflected in employees’ satisfaction and hence lower level of motivation. This fact led to lower performance and lower productivity. Unexpectedly, it was found that both companies suffered from low level of motivation among employees due to: poor incentive system, absent of encouragement, unfairness or obvious discrimination in key positions, inadequate training policy, limited benefits, and unfair distribution of promotions specifically in key managerial chairs at Batelco basically and in Zain to less extent. It was not known if this was created by policy makers and higher management; or, instead, by line managers who were suffering from inappropriate skills of motivation and poor knowledge of coaching. Upon the above findings, the study suggested the following measures for remedy: - Top management should create a clear plan of motivation based cooperation and goal achieving between employees and leaders. - Successful incentive system should be guaranteed. - Diffusion of team culture instead should be considered. - Fairly treatment among employees should be emphasised. - Efficient and clear appraisal system is considered. - Training and career development should be reinforced to all employees. - Exposing leaders to intensive coaching and leadership practices training sessions.This study is to examine selected issues, which are fundamentally related to management in general and to leadership in particular. The main objective of the study is to explore the domain of motivational and coaching skills within telecom business sector by using empirical analysis. It will explore, first, how leaders make effective use of motivational and coaching skills to improve employees’ performance in both Batelco and Zain; the two major leading companies in telecommunication, mobile services and internet market in Bahrain. Second, it will investigate the impact of leaders’ motivation and coaching techniques on [email protected] +973 3679665

Developing Motivational and Coaching Skills in Telecom Companies. A comparative study between Batelco and Zain, Bahrain

Over the last 20 years, the telecommunication industry has grown rapidly and has become one of the major business markets in the Kingdom of Bahrain. Today it can be considered as the fastest growing segment of trade and business development in the country. Since 2000, monopoly of the telecom market has been demolished as the government has modified the policy of licensing mobile enterprises. This, along with the advanced technology in telecom sector, has led to the launching of numerous competitors to the only telecom company, Batelco, including the fast growing company, Zain, with its comparative facilities and prices. The two major telecom companies; Batelco and Zain, are run and headed by Bahraini and non-Bahraini CEOs. This study is to examine selected issues, which are fundamentally related to management in general and to leadership in particular. The main objective of the study is to explore the domain of motivational and coaching skills within telecom business sector by using empirical analysis. It will explore, first, how leaders make effective use of motivational and coaching skills to improve employees’ performance in both Batelco and Zain; the two major leading companies in telecommunication, mobile services and internet market in Bahrain. Second, it will investigate the impact of leaders’ motivation and coaching techniques on employees. The hypotheses of the study are the following: 1. The motivational and coaching techniques implemented by the two companies in order to enhance performance of customer service representatives are extremely distinctive. 2. From employees’ perception, leaders are motivating to a specific extant in one company and demotivating in another. 3. The motivational techniques in both companies are matching the organisation’s objectives and employees' needs. 4. Managers are found to understand the concepts of a coach or a motivational leader in one company rather than the other. 5. The findings in the empirical part correspond to the theory in the field. The analysis has verified that a statistically significant relationship exists between existing motivational and coaching techniques and skills taken for granted by leaders, and employees’ satisfaction, and subsequently specific degree of performance within the two telecom organisations. The study showed that lower or inappropriate motivation practices at work place were reflected in employees’ satisfaction and hence lower level of motivation. This fact led to lower performance and lower productivity. Unexpectedly, it was found that both companies suffered from low level of motivation among employees due to: poor incentive system, absent of encouragement, unfairness or obvious discrimination in key positions, inadequate training policy, limited benefits, and unfair distribution of promotions specifically in key managerial chairs at Batelco basically and in Zain to less extent. It was not known if this was created by policy makers and higher management; or, instead, by line managers who were suffering from inappropriate skills of motivation and poor knowledge of coaching. Upon the above findings, the study suggested the following measures for remedy: - Top management should create a clear plan of motivation based cooperation and goal achieving between employees and leaders. - Successful incentive system should be guaranteed. - Diffusion of team culture instead should be considered. - Fairly treatment among employees should be emphasised. - Efficient and clear appraisal system is considered. - Training and career development should be reinforced to all employees. - Exposing leaders to intensive coaching and leadership practices training sessions.This study is to examine selected issues, which are fundamentally related to management in general and to leadership in particular. The main objective of the study is to explore the domain of motivational and coaching skills within telecom business sector by using empirical analysis. It will explore, first, how leaders make effective use of motivational and coaching skills to improve employees’ performance in both Batelco and Zain; the two major leading companies in telecommunication, mobile services and internet market in Bahrain. Second, it will investigate the impact of leaders’ motivation and coaching techniques on [email protected] +973 3679665