Adaptive Signal Processing for Power Line Communications

This thesis represents a significant part of the research activity conducted during the PhD program in Information Technologies, supported by Selta S.p.A, Cadeo, Italy, focused on the analysis and design of a Power Line Communications (PLC) system. In recent times the PLC technologies have been considered for integration in Smart Grids architectures, as they are used to exploit the existing power line infrastructure for information transmission purposes on low, medium and high voltage lines. The characterization of a reliable PLC system is a current object of research as well as it is the design of modems for communications over the power lines. In this thesis, the focus is on the analysis of a full-duplex PLC modem for communication over high-voltage lines, and, in particular, on the design of the echo canceller device and innovative channel coding schemes.

High-performance human resource practices, citizenship behaviour and organizational performance:A relational perspective

Taking a relational perspective on the employment relationship, we examined processes (mediation and moderation) linking high-performance human resource practices and productivity and turnover, two indicators of organizational performance. Multilevel analysis of data from hotels in the People's Republic of China revealed that service-oriented organizational citizenship behavior (OCB) partially mediated the relationships between high-performance human resource practices and both performance indicators. Unemployment rate moderated the service-oriented OCB-turnover relationship, and business strategy (service quality) moderated the service-oriented OCB-productivity relationship. Copyright of the Academy of Management, all rights reserved.

I don't see me like you see me, but is that a problem? Cultural influences on rating discrepancy in 360-degree feedback instruments

360-degree feedback from a variety of rater sources yields important information about leaders' styles, strengths and weaknesses for development. Results where observer ratings are discrepant (i.e., different) from self-ratings are often seen as indicators of problematic leadership relationships, skills, or lack of self-awareness. Yet research into the antecedents of such self-observer rating discrepancy suggests the presence of systematic influences, such as cultural values. The present study investigates the variation of rating discrepancies on three leadership skills (decision making, leading employees, and composure) in dependence of one exemplary culture dimension (power distance) on data from 31 countries using multilevel structural equation modelling. Results show that cultural values indeed predict self-observer rating discrepancies. Thus, systemic and contextual influences such as culture need to be taken into consideration when interpreting the importance and meaning of self-observer rating discrepancies in 360-degree instruments.

Job satisfaction and teamwork:The role of supervisor support

The link between teamwork and job satisfaction was investigated in a sample of 48 manufacturing companies comprising 4708 employees. Two separate research questions were addressed. First, it was proposed that supervisor support would be a weaker source of job satisfaction in companies with higher levels of teamworking. Multilevel analysis indicated that the extent of teamwork at the company level of analysis moderated the relationship between individual perceptions of supervisor support and job satisfaction. Second, it was proposed that the extent of teamwork would be positively related to perceptions of job autonomy but negatively related to perceptions of supervisor support. Further, it was proposed that the link between teamwork and job autonomy would be explained by job enrichment practices associated with teamwork. Analyses of aggregated company data supported these propositions and provided evidence for a complex mediational path between teamwork and job satisfaction. Implications for implementing teamwork in organizations are discussed. Copyright © 2001 John Wiley & Sons, Ltd.

Fast response static var generator for improving the power system performance of an electric arc furnace (EAF)

Cascaded multilevel inverters-based Static Var Generators (SVGs) are FACTS equipment introduced for active and reactive power flow control. They eliminate the need for zigzag transformers and give a fast response. However, with regard to their application for flicker reduction in using Electric Arc Furnace (EAF), the existing multilevel inverter-based SVGs suffer from the following disadvantages. (1) To control the reactive power, an off-line calculation of Modulation Index (MI) is required to adjust the SVG output voltage. This slows down the transient response to the changes of reactive power; and (2) Random active power exchange may cause unbalance to the voltage of the d.c. link (HBI) capacitor when the reactive power control is done by adjusting the power angle d alone. To resolve these problems, a mathematical model of 11-level cascaded SVG, was developed. A new control strategy involving both MI (modulation index) and power angle (d) is proposed. A selected harmonics elimination method (SHEM) is taken for switching pattern calculations. To shorten the response time and simplify the controls system, feed forward neural networks are used for on-line computation of the switching patterns instead of using look-up tables. The proposed controller updates the MI and switching patterns once each line-cycle according to the sampled reactive power Qs. Meanwhile, the remainder reactive power (compensated by the MI) and the reactive power variations during the line-cycle will be continuously compensated by adjusting the power angles, d. The scheme senses both variables MI and d, and takes action through the inverter switching angle, qi. As a result, the proposed SVG is expected to give a faster and more accurate response than present designs allow. In support of the proposal there is a mathematical model for reactive powered distribution and a sensitivity matrix for voltage regulation assessment, MATLAB simulation results are provided to validate the proposed schemes. The performance with non-linear time varying loads is analysed and refers to a general review of flicker, of methods for measuring flickers due to arc furnace and means for mitigation.

Work stressors, strains and hospital unit performance

Hospital employees who work in an environment with zero tolerance to error, face several stressors that may result in psychological, physiological, and behavioural strains, and subsequently, in suboptimal performance. This thesis includes two studies which investigate the stressor-to-strain-to-performance relationships in hospitals. The first study is a cross-sectional, multi-group investigation based on secondary data from 65,142 respondents in 172 acute/specialist UK NHS trusts. This model proposes that senior management leadership predicts social support and job design which, in turn, moderate stressors-to-strains across team structure. The results confirm the model's robustness. Regression analysis provides support for main effects and minimal support for moderation hypotheses. Therefore, based on its conclusions and inherent limitations, study one lays the framework for study two. The second study is a cross-sectional, multilevel investigation of the strain-reducing effects of social environment on externally-rated unit-level performance based on primary data from 1,137 employees in 136 units, in a hospital in Malta. The term "social environment" refers to the prediction of the moderator variables, which is to say, social support and decision latitude/control, by transformational leadership and team climate across hospital units. This study demonstrates that transformational leadership is positively associated with social support, whereas team climate is positively associated with both moderators. At the same time, it identifies a number of moderating effects which social support and decision latitude/control, both separately and together, had on specific stressor-to-strain relationships. The results show significant mediated stressor-to-strain-to-performance relationships. Furthermore, at the higher level, unit-level performance is positively associated with shared unit-level team climate and with unit-level vision, the latter being one of the five sub-dimension of transformational leadership. At the same time, performance is also positively related to both transformational leadership and team climate when the two constructs are tested together. Few studies have linked the buffering effects of the social environment in occupational stress with performance. Therefore, this research strives to make a significant contribution to the occupational stress and performance literature with a focus on hospital practice. Indeed, the study highlights the wide-ranging and far-reaching implications that these findings provide for theory, management, and practice.

The European Union and global governance:a handbook

The role of the European Union in global politics has been of growing interest over the past decade. The EU is a key player in global institutions such as the World Trade Organization (WTO) and NATO. It continues to construct an emerging identity and project its values and interests throughout contemporary international relations. The capacity of the EU to both formulate and realise its goals, however, remains contested. Some scholars claim the EU’s `soft power’ attitude rivals that of the USA’s `hard power’ approach to international relations. Others view the EU as insufficiently able to produce a co-ordinated position to project upon global politics. Regardless of the position taken within this debate, the EU’s relationship with its external partners has an increasingly important impact upon economic, political and security concerns on an international level. Trade negotiations, military interventions, democracy promotion, international development and responses to the global economic crisis have all witnessed the EU playing a central role. This has seen the EU become both a major force in contemporary institutions of global governance and a template for supranational governance that might influence other attempts to construct regional and global institutions. This volume brings together a collection of leading EU scholars to provide a state-of-the-art overview covering these and other debates relating to the EU’s role in contemporary global governance. The Handbook is divided into four main sections: Part I: European studies and global governance – provides an overview and critical assessment of the leading theoretical approaches through which the EU’s role in global governance has been addressed within the literature. Part II: Institutions – examines the role played by the key EU institutions in pursuing a role for the EU in contemporary international relations. Part III: Policy and issue areas – explores developments within particular policy sectors, assessing the different impact that the EU has had in different issue areas, including foreign and security policy, environmental policy, common commercial policy, the Common Agricultural Policy, development policy, accession policy, the Neighbourhood Policy and conflict transformation. Part IV: The global multilevel governance complex and the EU – focuses on the relationship between the EU and the institutions, regions and countries with which it forms a global multilevel governance complex, including chapters on the EU’s relationship with the WTO, United Nations, East Asia, Africa and the USA.

The role of the sales employee in securing customer satisfaction

Purpose: Previous research has emphasized the pivotal role that salespeople play in customer satisfaction. In this regard, the relationship between salespeople's attitudes, skills, and characteristics, and customer satisfaction remains an area of interest. The paper aims to make three contributions: first, it seeks to examine the impact of salespeople's satisfaction, adaptive selling, and dominance on customer satisfaction. Second, this research aims to use dyadic data, which is a better test of the relationships between constructs since it avoids common method variance. Finally, in contrast to previous research, it aims to test all of the customers of salespeople rather than customers selected by salespeople. Design/methodology/approach: The study employs multilevel analysis to examine the relationship between salespeople's satisfaction with the firm on customer satisfaction, using a dyadic, matched business-to-business sample of a large European financial service provider that comprises 188 customers and 18 employees. Findings: The paper finds that customers' evaluation of service quality, product quality, and value influence customer satisfaction. The analysis at the selling firm's employee level shows that adaptive selling and employee satisfaction positively impact customer satisfaction, while dominance is negatively related to customer satisfaction. Practical implications: Research shows that customer-focus is a key driver in the success of service companies. Customer satisfaction is regarded as a prerequisite for establishing long-term, profitable relations between company and customer, and customer contact employees are key to nurturing this relationship. The role of salespeople's attitudes, skills, and characteristics in the customer satisfaction process are highlighted in this paper. Originality/value: The use of dyadic, multilevel studies to assess the nature of the relationship between employees and customers is, to date, surprisingly limited. The paper examines the link between employee attitudes, skills, and characteristics, and customer satisfaction in a business-to-business setting in the financial service sector, differentiating between customer- and employee-level drivers of business customer satisfaction.

Which institutions encourage entrepreneurs to create larger firms

We develop entrepreneurship and institutional theory to explain variation in different types of entrepreneurship across individuals and institutional contexts. Our framework generates hypotheses about the negative impact of higher levels of corruption, weaker property rights and especially intellectual property rights, and a larger state on entrepreneurs who plan to grow faster. We test these hypotheses using the Global Entrepreneurship Monitor surveys in 55 countries for 2001-2006, applying a multilevel estimation framework. We confirm our main hypotheses but we find no significant impact from intellectual property rights.

Which institutions encourage entrepreneurial growth aspirations?

We develop entrepreneurship and institutional theory to explain entrepreneurial growth aspirations across individuals and institutional contexts. Our framework generates hypotheses at the national level about the negative impact of higher levels of corruption, weaker property rights and greater government activity on entrepreneurs' aspirations to increase employment. We further explore whether individual's social networks compensate for weaknesses in national institutions. We use the Global Entrepreneurship Monitor surveys in 42 countries for 2001-2006, applying a multilevel estimation framework to test our ideas. We find that the relationship between growth aspiring entrepreneurs and institutions is complex; they benefit simultaneously from strong government (in the sense of property rights enforcement), and smaller government, but are constrained by corruption. Social networks mediate some but not all institutional deficiencies. © 2012 Elsevier Inc.

The effects of transformational leadership behaviours on follower outcomes:an identity-based analysis

The aim of this study was to explore two of the mechanisms by which transformational leaders have a positive influence on followers. It examined the mediating role of follower's leader and group identification on the associations among different transformational leader behaviours and follower job satisfaction and supervisor-rated job performance. One hundred and seventy-nine healthcare employees and 44 supervisors participated in the study. The results from multilevel structural equation modelling provided results that partially supported the predicted model. Identification with the leader significantly mediated the positive associations between supportive leadership, intellectual stimulation, personal recognition, in the prediction of job satisfaction and job performance. Leader identification also mediated the relationship between supportive leadership, intellectual stimulation, personal recognition, and group identification. However, group identification did not mediate the associations between vision leadership and inspirational communication, in the prediction of job satisfaction and job performance. The results highlight the role of individualized forms of leadership and leader identification in enhancing follower outcomes.

The association between presenteeism and engagement of National Health Service staff

Objective: Although several studies have demonstrated a relationship between staff engagement and health and wellbeing, none has analysed the association with presenteeism in the National Health Service (NHS) context. Our aim is to determine whether there is a relationship between presenteeism and staff engagement. Methods: A hierarchical logistic multilevel modelling of cross-sectional data from the NHS staff survey (2009) was conducted. We controlled for a range of demographic and socioeconomic background variables, including ethnic group, gender, age and occupational group. The sample was 156,951 respondents across all 390 English NHS trusts, each providing a random sample of employees. Engagement was measured using three facets: motivation, advocacy and involvement, which were also used in a composite score. Results: Therewas a low-to-moderate negative correlation between presenteeismand staff engagement: odds ratio 0.42 (95% confidence interval [CI] 0.42-0.43) for overall staff engagement and 0.53 (95% CI 0.52-0.54) for staff advocacy of the trust; 0.53 (95% CI 0.52-0.54) for motivation and 0.50 (95% CI 0.49-0.51) for involvement. Conclusions: Putting pressure on health-care staff to come to work when unwell is associated with poorer staff engagement with their jobs. © The Royal Society of Medicine Press Ltd 2011.

Managing diversity in organizations:an integrative model and agenda for future research

The literature on policies, procedures, and practices of diversity management in organizations is currently fragmented and often contradictory in highlighting what is effective diversity management, and which organizational and societal factors facilitate or hinder its implementation. In order to provide a comprehensive and cohesive view of diversity management in organizations, we develop a multilevel model informed by the social identity approach that explains, on the basis of a work motivation logic, the processes by, and the conditions under which employee dissimilarity within diverse work groups is related to innovation, effectiveness, and well-being. Building on this new model, we then identify those work group factors (e.g., climate for inclusion and supervisory leadership), organizational factors (e.g., diversity management policies and procedures, and top management's diversity beliefs), and societal factors (e.g., legislation, socioeconomic situation, and culture) that are likely to contribute to the effective management of diversity in organizations. In our discussion of the theoretical implications of the proposed model, we offer a set of propositions to serve as a guide for future research. We conclude with a discussion of possible limitations of the model and practical implications for managing diversity in organizations. © 2014 Taylor & Francis.

Nothing succeeds like moderation:a social self-regulation perspective on cultural dissimilarity and individual performance.

Addressing inconsistencies in relational demography research, we examine the relationship between cultural dissimilarity and individual performance through the lens of social self-regulation theory, which extends the social identity perspective in relational demography with the analysis of social self-regulation. We propose that social self-regulation in culturally diverse teams manifests itself as performance monitoring (i.e., individuals' actions to meet team performance standards and peer expectations). Contingent on the status associated with individuals' cultural background, performance monitoring is proposed to have a curvilinear relationship with individual performance and to mediate between cultural dissimilarity and performance. Multilevel moderated mediation analyses of time-lagged data from 316 members of 69 teams confirmed these hypotheses. Cultural dissimilarity had a negative relationship with performance monitoring for high cultural-status members, and a positive relationship for low cultural-status members. Performance monitoring had a curvilinear relationship with individual performance that became decreasingly positive. Cultural dissimilarity thus was increasingly negatively associated with performance for high culturalstatus members, and decreasingly positively for low cultural-status members. These findings suggest that cultural dissimilarity to the team is not unconditionally negative for the individual but, in moderation, may in fact have positive motivational effects.