A research report submitted to the faculty of commerce of the University of the Witwatersrand in part completion of the degree of Master of commerce, by coursework / No abstract

The thesis is oriented to an alternative approach of allocation of overhead costs which arose in the second half of the nineties of the twentieth century. Activity Based Costing (ABC) is a way of cost control based on looking at costs through activities that are performed in the organization. The following determining of their costs is done based on dividing them into various cost pools with differentiated cost drivers that do not have to be volume based. The thesis is apart from the theoretical study of the topic supplemented by a survey of prevalence of ABC in the Czech Republic and primarily by an analysis of an already created strategic ABC model which is used for studying a degree of compliance of theoretical foundations of the principle with actual methods used in creating the ABC model.

[pt] Tradicionalmente, os equipamentos de elevação e transporte assumem uma posição de destaque na indústria, sendo as pontes rolantes os equipamentos mais utilizados. No caso da ThyssenKrupp Fundições Ltda., as pontes rolantes são responsáveis pelas principais paralisações dos negócios, trazendo prejuízos financeiros e operacionais. O emprego da IBR - Inspeção Baseada em Risco é bastante indicado para este tipo de equipamento, pois permite identificar as pontes rolantes que são críticas e deste modo estabelecer uma metodologia de inspeção eficiente, visando concentrar esforços nestes equipamentos de modo a reduzir seu risco de falha e garantir a manutenção dos negócios. Neste trabalho analisou-se um conjunto de pontes rolantes e componentes críticos da empresa ThyssenKrupp Fundições Ltda.. Para se cumprir este objetivo, foi aplicada a metodologia de IBR qualitativa para a análise do banco de dados de manutenção e inspeção. A teoria de IBR qualitativa usou uma matriz de risco COF x FOF (Conseqüência de Ocorrência de Falhas X Freqüência de Ocorrência de Falhas) onde cada uma das 20 pontes teve sua classe de risco estabelecida. Também foi feita a análise da freqüência de falhas dos componentes de todas as 20 pontes através dos registros de inspeção e manutenção localizados dentro do período de janeiro de 1995 a junho de 2002. Após a determinação das pontes rolantes críticas (risco alto e muito alto) e componentes críticos, foi elaborado um programa de inspeção para o gerenciamento dos mesmos, através de tabelas e fichas de inspeção onde a nova freqüência de inspeção foi calculada através da distribuição de probabilidade semi-empírica de Weibull. Além do programa de inspeção, foi proposta uma metodologia para análise dos resultados futuros obtidos com a aplicação do programa de inspeção e para proporcionar, através da realimentação do banco de dados, o contínuo aumento de sua eficiência. / [en] Traditionally, the transportation and elevation equipments assume a highlight position in the industry, being the overhead crane one of the mostly used equipments. As to the ThyssenKrupp Fundições Ltda, the overhead cranes are responsible for main causes for stopping of business, leading financial and operational lost. The use of RBI - Risk Based Inspection is very well indicated for this type of equipment since it allows the identification of which overhead cranes are critical and in this way the establish a mean of efficient inspection methodology, aiming to concentrate efforts on these equipments so as to reduce their failure risk and to guarantee the maintenance of the business. In this dissertation, a sub-set of overhead cranes and critical components of ThyssenKrupp Fundições Ltda was analyzed. In order to reach this objective, the RBI qualitative methodology was applied to the analysis of the maintenance and inspection database. The theory of the qualitative RBI used a risk matrix FOF x COF (Probability of Failure X Consequence of Failure) where each one of the 20 overhead crane had its class of risk established. Also, the components failure analysis frequency of all the 20 overhead cranes was made through the inspection registries situated in the period between January 1995 and June 2002. After determining the critical overhead crane (high and very high risk) and the critical components, an inspection program for their management was elaborated through means of table and inspection cards where the new inspection frequencies were determined through the Weibull distribution semi-empiric probability. Besides the inspection program, a methodology to analyze the future results obtained by the application of the inspection program was propose to offer suggestions for this continuous efficience raise.

Mobile Ad hoc Networks (MANETs) are wireless networks, which consist of a collection of mobile nodes with no fixed infrastructure, where each node acts as a router that participates in forwarding data packets. They are a new paradigm of wireless communications for mobile hosts that are resource-constrained with only limited energy, computing power and memory. Previous studies on MANETs concentrated more on energy conservation in an idealistic environment without taking into consideration, the effects of realistic mobility, interference and fading. The definition of realistic mobility models is one of the most critical and, at the same time, difficult aspects of the simulations of networks designed for real mobile ad hoc environments. The reason for this is that most scenarios for which ad hoc networks are used have features such as dynamicity and extreme uncertainties. Thus use of real life measurements is currently almost impossible and most certainly expensive. Hence the commonly used alternative is to simulate the movement patterns and hence the reproduction of movement traces quite similar to human mobility behavior is extremely important. The synthetic models used for movement pattern generation should reflect the movement of the real mobile devices, which are usually carried by humans, so the movement of such devices is necessarily based on human decisions. Regularity is an important characteristic of human movement patterns. All simulated movement models are suspect because there is no means of accessing to what extent they map reality. However it is not difficult to see that random mobility models such as Random Walk, Random Waypoint (default model used in almost all network simulations), etc., generate movements that are most non-humanlike. Hence we need to focus on more realistic mobility models such as Gauss Markov, Manhattan Grid, Reference Point Group Mobility Model (RPGM), Column, Pursue and other Hybrid mobility models. These models capture certain mobility characteristics that emulate the realistic MANETs movement, such as temporal dependency, spatial dependency and geographic restriction. Also a Rayleigh/Ricean fading channel is introduced to obtain a realistic fading environment. The energy consumed by the data, MAC, ARP and RTR packets using IEEE 802.11 MAC protocol with the various mobility models in fading and non-fading channel conditions are obtained using ns-2 simulations and AWK programs. The realistic movement patterns are generated using three different mobility generators BonnMotion Mobility Generator, Toilers Code and Scengen Mobility Generator. This thesis work performs an in-depth study on th eeffects of realistic mobility and fading on energy consumption, packet delivery ratio and control overhead of MANETs.

In this work we consider the overhead power transmission lines (OHL). Their specifics are related to the presence of cables (conductors) whose length between supporting towers may extend to dozens of thousand meters. The OHL components are exposed to a combination of natural actions wind, rain, ice / snow / frost deposits. Compared to other structural parts, conductors have the highest flexibility and very low structural self-damping (of the order of 0.1 % of critical damping or lower, depending on frequencies). They are among structural elements the most sensitive to these actions. Since early fifties the increased energy demand gave a rise to large construction of high-voltage and extra-high-voltage overhead lines equipped with bundled electrical conductors. For such arrangements there was noticed a kind of wind-induced oscillations originated by a zone of disturbed and retarded air flow (wake), that the cables located upwind(windward) cast onto the downwind (leeward) ones. The effect of this phenomenon called Wake-Induced Oscillations (WIO) resulted in fatigue damages of conductors, failures of insulator strings and cable suspension hardware and fatigue failures of spacers. There have been identified analogues to transmission lines WIO in other regular structures subjectto the cross-flow of viscous fluids (air, gas, water etc.): heat exchanger tubes, clusters of fuel rods of nnuclear reactors, groups of chimneys, buildings. Early works in this field relate to the aerodynamics of tandem and staggered twin struts to support the wings of biplanes and published by Pannell, Griffits and Coales in 1915. Other cable structures like suspenders in suspension bridges or stays in cable-stayed bridges may be also subject to wake-induced oscillations. In each of these cases, conditions of oscillations occurrence and structural response depend on cables specific mass and stiffness, kind of fixation, dimension scale versus fluid viscosity and velocity (Reynolds number) etc. The cables separation plays important role, as there are different kinds of wake interference especially when the cables are closely spaced. A number of research projects were entertained to study the wake-induced oscillations of different structures, which brought to development of analytical and experimental models and methods of protection against this phenomenon. A particular solution to overhead lines was found by unevenly distributing the spacers along the line span. To achieve that, no unique approach exists; virtually each grid company, or manufacturer of spacers proceeds with its own method. It may rely on different basis, either field experience or analytical study or a mixture of them. And, despite advances in numerical modelling of latest decades, few publications uncover phenomenological side of WIO. The issues of modelling WIO in a view of helping to develop methods for protection of line against WIO are a main subject of this work. Original advances studied in this thesis include: - Current state-of-the art for analytical calculation of WIO, including the loads in the wake - Overview of classic theory of wake-induced flutter and its evaluation from the standpoint of modern numerical tools for analytical applications (e.g., Matlab) - Nonlinear Finite-Element Modelling of WIO using classic theory of wake-induced flutter, study of its domains of application, advantages and limitations, including validation upon field experiments - Foundation of basic methodology for optimal placement of spacers over the bundle conductor span

Thesis--Ph. D., University of Hong Kong. / Mimeographed.

Dagens samhälle präglas av ständiga förändringar i omvärlden. Internationalisering, globalisering och teknikutveckling är faktorer som leder till en ökad global konkurrens för företagen, vilket gjort att företag måste förbättra sina processer för att vara fortsatt konkurrenskraftiga och lönsamma. Det ständigt förändrade samhället kräver en väl genomförd ekonomistyrning för att företag ska kunna följa med i utvecklingen. Tillverkande företag är en stor del av det svenska näringslivet och måste därmed anpassa sig i den takt som globaliseringen sker. Många forskare har identifierat en kunskapslucka mellan ekonomistyrning i teori och praktik, då mycket forskning och utveckling av metoder inom ekonomistyrningen äger rum utan att man ser till hur detta uppfattas i praktiken.   Syftet med denna studie är att se vilka orsaker som kan förklara varför eventuella kalkylavvikelser uppstår i ett tillverkande företag inom fordonsindustrin i Sverige, samt hur dessa avvikelser kan påverkas och reduceras genom aktiv påverkan i det dagliga arbetet. Med intern benchmarking och Kaizen som verktyg vill vi öka kunskapen om dessa avvikelser och hur de kan påverkas, för att sedan reduceras och ge en bättre precision i förkalkylerna. Studien har genomförts med intervjuer, möten och observationer på två fallavdelningar i ett större tillverkande företag, för att skapa en djupare förståelse. Vidare har studien genomförts med ett kvalitativt tillvägagångssätt.   Resultaten vi funnit genom studien visar att möjligheten till att påverka de kalkylavvikelser som uppstår är stor. Möjligheten till aktiv påverkan skiljer sig beroende på vilken position i företaget respondenterna har. Studien visar att de flesta respondenter anser att tidsbrist är den största anledningen till att de inte använder sig mer av verktyg för påverkan såsom Kaizen och intern benchmarking. Vidare har vi funnit att medarbetare motiveras av mer än enbart monetär ersättning, såsom att få gehör och muntlig uppmuntran. Av studien kan konstateras att olika verktyg för effektiviseringar i teorin ofta framställs som oproblematiska och enkla att implementera, men i verkligheten och praktiken är det mer komplicerat. / Today´s society is characterized by constant changes in the business environment. Internationalization, globalization and development in technology are factors that lead to increased global competition between companies, why companies must improve their processes to remain competitive and profitable. The constantly changing society requires a well-implemented management control to keep up with the development, Manufacturing companies represents a big part of the Swedish industry. The companies must therefore adapt to the pace of globalization. Researchers have identified a gap in knowledge between management control in theory and practice. Research and development of methods for management control take place without ensuring how it is perceived in practice.   The purpose of this study is to define the reasons that explain why calculated deviations occur in the automobile industry in Sweden and how these deviations can be affected and reduced by active impact in the daily work. Our hope is to increase the knowledge about the deviations; how they can be affected, reduced and give a better precision in the calculations, with internal benchmarking and Kaizen as tools. The study was accomplished by interviews, meetings and observations of two departments in a large manufacturing company in order to create a deeper understanding. The study carried out with a qualitative approach.   The results we have found show that there is a great ability to affect the deviations. The opportunity for active impact differs depending on the respondent´s position in the company. The study shows that most respondents consider the lack of time as the main reason why they don´t use instruments for active impact, such as Kaizen and internal benchmarking. Furthermore we have found that employees are motivated by more than just monetary compensations, such as verbal encouragement and being noticed. The study concludes that different instruments for increasing efficiency in theory often is presented as unproblematic and easy to implement, but in reality and practice it is more complicated.

(Uncorrected OCR) Abstract of thesis entitled liField analysis in power supply lines by integraJ. equation methodll subm1 tted by FOe, PIK YlJE for the degree of Ph.D at the University of Hong Kong in December, 1974. Abstract In this thesis, the integral equation (I.E.) method has been employed successfully to solve field problems in power supply lines. Though the I.E. method is mathematically quite involved, it is shown that it is possible to treat the integral equation as a system of linear equations. Hence the transformed simultaneous linear equations can be considered as the starting point for solving problems either in overhead lines or \Ulderground power cables. In overhead lines, especially in Extra-High-Voltage and Ultra- High-Voltage systems, an evaluation of the electric field near each conductor, especially the maximum electric field, is essential as corona and radio interference become important considerations in the design of such lines. The I.E. method has many advantages over the other existing methods in calculating the potential gradient at the surface of the overhead lines in that it yieldS reasonably accurate results with comparatively simple numerical computations. The difference between the present method and the existing methods is the basic assumption. In the I.E. method, subconductor surfaces are treated as equipotential lines whereas in other existing methods, the subconductor surfaces usually do not coincide with the simulated equipotential lines. The method can also be applied equally well to symmetrical or asymmetrical bundle conductors with or without ground wires. Other parameters such as capacitances, potential gradients at the earth surface etc. are also included in the computer program. In underground cable systems, the I. E. method proves to be very effective in tackling the thermal field problem, especially when the cables are buried shallow and thus the earth i s surface can no longer be treated as isothermal. .It has been found that the thermal resistance (external) obtained wi::;h a non-isothermal earth surface is considerably higher than that obtained under the assuumption of an isothermal earth surface. With non.-isothermal earth surface, the temperature difference on the earth surface between the spot vertically above the cable and the spot at a distance eClual to twice the depth of burial of the cable away could be as high as lOoe. The finite-difference or fini te-搪lement method could likewise be used to solve the problem of a non-isothermal ea>:>th surface, but the computer storage re'luired and the execution time would be much more than that using the I.E. method. / abstract / toc / Electrical and Electronic Engineering / Doctoral / Doctor of Philosophy

No description available.

Signaling Overhead has always been a concern for network operators. LTE offers many improvements aimed at improved network performance and management. This thesis exploit Tracking Area List (TAL) concept in LTE networks. An algorithm to design TAL using UE traces is developed. The performance of TAL design is compared to conventional TA design. Performance is also compared with rule of thumb TAL design which is another approach to designing TAL