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A two‐dimensional electromagnetic field model of a railway track and traction line is used to determine the equivalent track distributed transmission line parameters in the frequency range DC to 30kHz. The model is solved using the finite‐element method to find the minimum energy condition for two conditions: current excitation to obtain the resistance and inductance, and voltage excitation for the conductance and capacitance. The results have been confirmed using practical test data, and their application is illustrated in a time‐domain circuit simulation to model interference between power and signalling currents in a 750V DC electric railway.

Purpose – Criminal groups have long been central to explanations of crime and deviance. Yet, challenges in measuring their dynamic and transient nature meant that group-level explanations were often displaced in favor of individual-level ones. This chapter outlines how network methods provide a powerful tool for modeling the dynamic nature of criminal groups.

Approach – The chapter starts by providing a brief introduction to social network analysis, including key concepts and terminology. The chapter then focuses on the types of relational data available to study criminal groups, and how network methods can be used to delineate group boundaries. The chapter concludes by presenting a framework for understanding group dynamics from a network perspective, describing the contributions of network analysis to theories of group processes.

Findings – Network methods have provided meaningful advances to the study of group dynamics, leading scholars to revisit assumptions about the impact of group’ structure on delinquent behavior. Network studies of group dynamics have primarily focused on the cohesion–delinquency link (within-group structure) and the social contagion of conflict (between-group structure), highlighting important opportunities for the intersection of these two inquiries.

Value – Network methods provide a means to revisit and extend theories of crime and delinquency with a focus on social structure. The unique affinity between group dynamics and network methods highlights immense opportunities for expanding the knowledge of collective trajectories.

Controversy in the literature exists over whether self-employment is driven by worker’s deliberate entrepreneurial choices (pull factors) or an indeliberate subsistence employment option (push factors) in developing countries. It is therefore very important to investigate whether the self-employed are the dynamic entrepreneurial group or the subsistence-oriented group. In this chapter, the authors examine the driving forces behind the plausible growth of self-employment in urban and rural Nigeria by analyzing the self-employment choices as a function of employment’s differences in predicted earnings, human capital, demographic and family characteristics. Using the 2010/2011 and 2012/2013 waves of the General Household Survey Panel data for Nigeria, this chapter utilizes the Random Effects Regression Models (OLS and Probit Models). This chapter finds that the predicted individual earning differences between self- and paid-employment has a negative significant effect on self-employment choices – contrary to developed countries’ evidence. In other words, overwhelmingly the poor are “entrepreneurs.” This therefore means that self-employment choice is driven by the necessity of survival – the subsistence self-employed groups rather than the dynamic entrepreneurial hypothesis. The implication of these finding is unique and interesting for an African country such as Nigeria where the self-employees are vulnerable to poverty and perhaps an involuntary employment option conditioned by economic failures.

Looks at the evolution of the workforce within the retailing industry and considers the victims of pay discrimination which now exist. Discusses various theories for the pay discrimination among women and minorities. Suggests some remedies that may minimize these inequalities. Concludes that the application of affirmative actions and diversity programmes should continue to serve as fundamental sources of workforce diversity and that new legislation/regulation may be required to protect those disadvantaged.

The benchmark problem 4 (the FELIX brick) defined in the International Workshops for Eddy Current Code Comparison is solved by 11 different computer codes. This problem is time‐dependent and three dimensional eddy current problem with a hole. 13 sets of results in total are presented. The results are in fairly good agreement although the formulations and methods in the codes are different from each other. The problem of the hole (multi‐connectivity) is successfully solved in the results.

This study aims to investigate the effectiveness of a theory-driven realist evaluative research approach to better understand complex technology implementations in organizations.

An institution wide e-learning implementation of lecture capture (LC), within a UK University, was chosen, and a realist evaluation framework was used, tailored for educational technology. The research was conducted over four, increasingly focused, evaluation cycles combining engagement analytics, user interviews and theory to refine what works (or does not work), for whom, in which contexts and why.

Despite explicit demand and corresponding investment, overall student engagement is lower than expected. Increased student use appears linked to particular staff attitudes and behaviours and not to specific disciplines or course content. The main benefits of LC are providing reassurance to the majority, aiding revision and understanding for the many and enabling catch-up for the few. Recommendations for future research are based on some unexpected outcomes uncovered, including evolving detrimental student behaviours, policy development based on technological determinism and future learner-centred system development for next-generation LC technologies.

The realist approach taken, and evaluation framework used, can be adopted (and adapted) for future evaluative research. Domain specific reference models, categorizing people and technology, supported analysis across multiple contexts.

This study responds to a call for more theory-based research in the field of educational technology. The authors demonstrate that a theory-driven approach provides real and practical recommendations for institutions and allows for greater insight into the political, economic and social complexity of technology implementation.

This paper aims to give a perspective about the variety of techniques which are available and are being further developed in the area of coupled field formulations, with selective bibliography and practical examples, to help postgraduate students, researchers and designers working in design or analysis of electrical machinery.

This paper reviews the recent trends in coupled field formulations. The use of these formulations for designing and non‐destructive testing of electrical machinery is described, followed by their classifications, solutions and applications. Their advantages and shortcomings are discussed.

The paper gives an overview of research, development and applications of coupled field formulations for electrical machinery based on more than 160 references. All landmark papers are classified. Practical engineering case studies are given which illustrate wide applicability of coupled field formulations.

Problems which continue to pose challenges to researchers are enumerated and the advantages of using the coupled‐field formulation are pointed out.

This paper gives a detailed description of the application of the coupled field formulation method to the analysis of problems that are present in different electrical machines. Examples of analysis of generators and transformers with this formulation are presented. The application examples give guidelines for its use in other analyses.

The coupled‐field formulation is used in the analysis of rotational machines and transformers where reference data are available and comparisons with other methods are performed and the advantages are justified. This paper serves as a guide for the ongoing research on coupled problems in electrical machinery.

Benchmark problem 5 of the TEAM workshops consists of four aluminium blocks placed in the space between the jaws of an electromagnet. Three dimensional eddy currents are induced by 50 Hz time‐varying flux. Eleven sets of results from nine groups of contributors are compared with experimental measurements. The results from most of the computer codes tend to converge to common limits. These limits are in some places slightly different from some of the measured results. The reason for this discrepancy is thought to be due to the idealised boundary conditions, ignoring any losses in laminated iron, which are assumed in all the computer models.

A new method for the numerical computation of the dynamic behaviour of electro‐dynamic loudspeakers is presented. The numerical scheme, based on the finite element method (FEM), allows the simulation of coupled magnetic, mechanical and acoustic fields. The obtained simulation results are in good agreement with measured data.

The main purpose of this paper is to investigate two key elements of localization and mapping of Autonomous Underwater Vehicle (AUV), i.e. to overview various sensors and algorithms used for underwater localization and mapping, and to make suggestions for future research.

The authors first review various sensors and algorithms used for AUVs in the terms of basic working principle, characters, their advantages and disadvantages. The statistical analysis is carried out by studying 35 AUV platforms according to the application circumstances of sensors and algorithms.

As real‐world applications have different requirements and specifications, it is necessary to select the most appropriate one by balancing various factors such as accuracy, cost, size, etc. Although highly accurate localization and mapping in an underwater environment is very difficult, more and more accurate and robust navigation solutions will be achieved with the development of both sensors and algorithms.

This paper provides an overview of the state of art underwater localisation and mapping algorithms and systems. No experiments are conducted for verification.

The paper will give readers a clear guideline to find suitable underwater localisation and mapping algorithms and systems for their practical applications in hand.

There is a wide range of audiences who will benefit from reading this comprehensive survey of autonomous localisation and mapping of UAVs.

The paper will provide useful information and suggestions to research students, engineers and scientists who work in the field of autonomous underwater vehicles.