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The continuing trend towards increasingly compact circuitry places rigorous demands on the thermal management of electronic assemblies. The problem is particularly severe in power circuitry with integrated control. A number of advanced cooling mechanisms and packaging methods are available, but for consumer products the cost of these solutions is prohibitive. Traditionally, thermal management has been achieved by the attachment of large metal heatsinks, but this introduces further manufacturing processes during assembly. It is demonstrated that efficient heatsinking can conveniently be achieved through the substrate, due to both improvements in, and shortening of, the conduction paths. When used as the final level of packaging in a hybrid assembly, coated steel substrates offer an improvement in thermal performance, in comparison with alumina. The optimum thermal performance is, however, provided by polymer coated aluminium substrate materials.

The World Health Organization′s project “Health for All in 2000” sets levels for future health care and provision for member states. In the UK a Healthy Cities Network has been established and many towns and cities are actively considering ways of working towards attaining these levels. This involves a number of different organizations and agencies working together to build models showing all the factors and relationships which affect the health of a community. The study aims to assess the potential of cognitive mapping techniques in providing not only a consensus view, but also a better understanding of those factors and relationships.

This paper presents reliability and availability analyses of a robot‐safety system having one robot and n‐redundant safety units with common‐cause failures. The system failure rates and the partially failed system repair rates are assumed constant, and the failed system repair time is assumed arbitrarily distributed. Markov and the supplementary variable methods were used to perform mathematical analysis of this model. Generalized expressions for state probabilities, system availabilities, reliability, mean time to failure, and variance of time to failure are developed. Some plots of these expressions are shown.

Modern mathematicians and scientists of math-related disciplines often use Document Preparation Systems (DPS) to write and Computer Algebra Systems (CAS) to calculate mathematical expressions. Usually, they translate the expressions manually between DPS and CAS. This process is time-consuming and error-prone. The purpose of this paper is to automate this translation. This paper uses Maple and Mathematica as the CAS, and LaTeX as the DPS.

Bruce Miller at the National Institute of Standards and Technology (NIST) developed a collection of special LaTeX macros that create links from mathematical symbols to their definitions in the NIST Digital Library of Mathematical Functions (DLMF). The authors are using these macros to perform rule-based translations between the formulae in the DLMF and CAS. Moreover, the authors develop software to ease the creation of new rules and to discover inconsistencies.

The authors created 396 mappings and translated 58.8 percent of DLMF formulae (2,405 expressions) successfully between Maple and DLMF. For a significant percentage, the special function definitions in Maple and the DLMF were different. An atomic symbol in one system maps to a composite expression in the other system. The translator was also successfully used for automatic verification of mathematical online compendia and CAS. The evaluation techniques discovered two errors in the DLMF and one defect in Maple.

This paper introduces the first translation tool for special functions between LaTeX and CAS. The approach improves error-prone manual translations and can be used to verify mathematical online compendia and CAS.

This survey studies the factors influencing the turnover intention of accountants in Singapore with a view to develop a turnover prediction model. Twenty variables were studied. Results show that 18 of these variables are significantly different between accountants who intend to turnover and those who do not. Through the use of stepwise logit analysis, a turnover prediction model with only six variables was developed. In‐sample and holdout overall accuracy rates of the turnover model are 88.2% and 87.4%, respectively.

Presents five newly developed models for a Triple Modular Redundancy system having zero, one, two, three, and N voters. Expressions for reliabilities and mean time to failure with and without repair are developed. The plots for state probabilities, reliabilities and mean time to failure are shown.

The linear analysis presented for the charge pump phase locked loops (CPPLLs) becomes inaccurate or incorrect where cycle slipping occurs. In this paper, an analytical approach is proposed, which explains the conditions in which cycle slipping happens. Using the analytical results, one can simply design or redesign a CPPLL to prevent or decrease cycle slipping and hence decreasing the locking time. The paper aims to discuss these issues.

To obtain cycle slipping conditions, CPPLL's signals in the time domain are tracked and cycle slipping condition is investigated. Based on the proposed analysis, by comparing a simple function of system's parameters with a threshold, cycle slipping is predicted.

The cycle slipping conditions are expressed in terms of system's parameters and the size of the input frequency step. The method is also generalized for a fast CPPLL with an aid-lock BBFC circuit. The good accuracy of the analytical predictions is verified using simulations in Matlab/Simulink.

A new analytical method for cycle slipping prediction in CPPLLs is presented. A closed form equation in terms of system's parameters and input frequency step has been presented, which can predict the cycle slipping possibility in the system without a need to perform the full time-consuming simulations. This analytical method that uses the LambertW function's properties proposes a threshold to predict cycle slipping in the system. This method not only can be used by designers to predict cycle slipping but can also be used to design the CPPLL in order to remove or decrease cycle slipping. The method is also generalized for fast locking charge pump PLLs and as a case study, cycle slipping prediction in the BBFC-CPPLL is performed.

The purpose of this paper is to develop a fast and accurate analytic model function for the single-valued H-B curve of ferromagnetic materials, where hysteresis can be disregarded (normal magnetization curve). Nonlinear magnetoquasistatic simulations demand smooth monotone material models to ensure physical correctness and good convergence in Newton's method.

The Brauer model has these beneficial properties, but is not sufficiently accurate for low and high fields in the normal magnetization curve. The paper extends the Brauer model to better fit material behavior in the Rayleigh region (low fields) and in full saturation. Procedures for obtaining optimal parameters from given measurement points are proposed and tested for two technical materials. The approach is compared with cubic spline and monotonicity preserving spline interpolation with respect to error and computational effort.

The extended Brauer model is more accurate and even maintains the computational advantages of the classical Brauer model. The methods for obtaining optimal parameters yield good results if the measurement points have a distinctive Rayleigh region.

The model function for ferromagnetic materials enhances the precision of the classical Brauer model without notable additional simulation cost.

The Colebrook equation for determination of hydraulic resistances is implicit in fluid flow friction factor and hence it has to be approximately solved using iterative procedure or using some of the approximate explicit formulas developed by many authors. The purpose of this paper is to compare different Lambert W based solutions of the Colebrook equation and to make comparisons among them and identify some constraints in applicability of certain solutions.

Alternate mathematically equivalents to the implicit Colebrook equation in explicit form with no approximation involved actually exist.

These alternate equations were developed using Lambert W‐function. The paper compares various implementations of the Lambert W methodology and shows that some of these are less able than others to yield solutions using modern computer hardware. This is because the functions require the evaluation of terms with numerical values outside the ranges that can be expressed on most computers.

Some of existed transformations cannot be applied for high values of relative roughness of inner pipe surface and the Reynolds number. This limitation applied only for computer computations. Other presented transformations do not sufferer of this limitation.

Presented procedures can be easily implemented in a computer code. Recommended solution can be used in all cases that can occur in engineering practice.

The paper shows some possible practical procedures for solution of the transformed Colebrook equation. Accuracy analysis and comparisons of presented formulas are also performed and recommendation for use is shown.

This study surveys the level of job satisfaction among government auditors in Singapore and investigates the factors affecting their job satisfaction. A questionnaire is administered in mid July 1990 to all the 150 government auditors in the Auditor‐General's Office in Singapore, resulting in a usable response rate of 76%. Descriptive statistics, t‐tests, wilcoxon Z tests, and Chi‐square tests of independence are used to analyse the data. Results of the survey show that government auditors in Singapore are very satisfied with their supervisors and co‐workers but very dissatisfied with the opportunities for promotion. Overall, however, they are satisfied with their jobs. Further, it is found that demographic factors such as sex, number of years in the present position, previous job, and income affect job satisfaction. Finally, the results show that the following factors are important determinants of Job satisfaction among government auditors in Singapore: (1) control over work, (2) frequency of sudden demands, (3) perceived necessity of overtime, (4) effect of sudden demands, (5) administrative supports, (6) interaction with supervisor, (7) physical work environment, (8) preparation for future career goals, and (9) extra‐organizational job opportunities.