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The ideal squirrel cage motor should have a varying rotor resistance; large at standstill, and decreasing as the speed rises. Overseas - designed high impedance rotors try to fulfil these conditions - mostly used are double cage rotors and die cast aluminium rotors. However, in the South African coal-mining industry these rotors recorded high rate failures with heavy financial losses. As a result, the need for an alternative rotor type that was able to comply with basic conditions ignored before appeared on the market: • Higher reliability with extended life expectancy • Lower total ownership costs • Easy re-manufacturing with components available on the market • Specific performance stability at competitive price. Over the years, only two principles were tacitly accepted in designing squirrel cage rotors: 1. For a single cage rotor, in a circumferential direction around the rotor the squirrel cage bars are placed in the same cylindrical shell, with the same shape and same conductivity. 2. For a double cage rotor, the same rule as above applies; however, in the radial direction, the bars have different shapes and typically different conductivities. The Invention is based on a new principle, i.e. "in a circumferential direction around the squirrel cage rotor, squirrel cage bars may have different conductivities and same shapes, or different conductivities and different shapes”. Mixed Conductivity Fabricated Rotors (MCFR) are designed and manufactured based on this new principle, and are able to withstand the harsh South African mining conditions. Since patented, the invention has been materialised in a set of special rotors powering continuous miners of a reputable coal-mining house, which was spending about R5 million annually on replacing specific imported die cast aluminium rotors only. Fully complying with the above-mentioned basic conditions, the patent offers a large variety of technical and economical advantages, increasing mining processes efficiency beyond expectations. The thesis describes the MCFR's design adaptability by altering the rotor design to meet the demands of a specific engineering application as a base line of drives design. The patent is part of the new South African trend of increasing processes efficiency. It offers large possibilities of designing dedicated motors with a positive impact on the South African economy. Some socio-economical advantages are worthy of considerable study: • Being locally manufactured, the MCFR may reduce the country's economical dependence. • Requiring no special expertise, the MCFR can be produced in any quantity and size without excessive investment. • The MCFR offers an alternative option (product interchangeability) on the market as well as sound competition (with export potential). • The patent ensures business sustainability conditions which diffuse financial constraints on motor manufacturers and end-users during the re-capitalisation process (very loaded in South African economic and industrial environment). / Thesis (Ph.D. (Electrical Engineering))--North-West University, Potchefstroom Campus, 2007.

Thesis (Ph.D. (Electrical Engineering))--North-West University, Potchefstroom Campus, 2007.

The ideal squirrel cage motor should have a varying rotor resistance; large at standstill, and decreasing as the speed rises. Overseas - designed high impedance rotors try to fulfil these conditions - mostly used are double cage rotors and die cast aluminium rotors. However, in the South African coal-mining industry these rotors recorded high rate failures with heavy financial losses. As a result, the need for an alternative rotor type that was able to comply with basic conditions ignored before appeared on the market: • Higher reliability with extended life expectancy • Lower total ownership costs • Easy re-manufacturing with components available on the market • Specific performance stability at competitive price. Over the years, only two principles were tacitly accepted in designing squirrel cage rotors: 1. For a single cage rotor, in a circumferential direction around the rotor the squirrel cage bars are placed in the same cylindrical shell, with the same shape and same conductivity. 2. For a double cage rotor, the same rule as above applies; however, in the radial direction, the bars have different shapes and typically different conductivities. The Invention is based on a new principle, i.e. "in a circumferential direction around the squirrel cage rotor, squirrel cage bars may have different conductivities and same shapes, or different conductivities and different shapes”. Mixed Conductivity Fabricated Rotors (MCFR) are designed and manufactured based on this new principle, and are able to withstand the harsh South African mining conditions. Since patented, the invention has been materialised in a set of special rotors powering continuous miners of a reputable coal-mining house, which was spending about R5 million annually on replacing specific imported die cast aluminium rotors only. Fully complying with the above-mentioned basic conditions, the patent offers a large variety of technical and economical advantages, increasing mining processes efficiency beyond expectations. The thesis describes the MCFR's design adaptability by altering the rotor design to meet the demands of a specific engineering application as a base line of drives design. The patent is part of the new South African trend of increasing processes efficiency. It offers large possibilities of designing dedicated motors with a positive impact on the South African economy. Some socio-economical advantages are worthy of considerable study: • Being locally manufactured, the MCFR may reduce the country's economical dependence. • Requiring no special expertise, the MCFR can be produced in any quantity and size without excessive investment. • The MCFR offers an alternative option (product interchangeability) on the market as well as sound competition (with export potential). • The patent ensures business sustainability conditions which diffuse financial constraints on motor manufacturers and end-users during the re-capitalisation process (very loaded in South African economic and industrial environment). / Thesis (Ph.D. (Electrical Engineering))--North-West University, Potchefstroom Campus, 2007.

<p>This thesis presents the development of a prototype of the Baseline Oriented Modeling</p><p>(BOM) approach, called protoBOM.</p><p>BOM is a framework that semi-automatically generates Decision Support Systems in a</p><p>specific domain, based on Software Product Lines.</p><p>protoBOM semi-automatically generates applications as PRISMA architectural models by using Model-Driven Architecture and Software Product Line techniques. These models are automatically compiled and the object code (C#, in .NET) is generated obtaining an executable application.</p><p>In protoBOM, the user constructs Decision Support Systems in a simpler way by using the</p><p>ontologies of the diagnosis and the application domains by means of Domain Specific Languages. The interfaces will be closer to the problem domain, which will facilitate user interaction in a manner simple and intuitive.</p>

This thesis presents the development of a prototype of the Baseline Oriented Modeling (BOM) approach, called protoBOM. BOM is a framework that semi-automatically generates Decision Support Systems in a specific domain, based on Software Product Lines. protoBOM semi-automatically generates applications as PRISMA architectural models by using Model-Driven Architecture and Software Product Line techniques. These models are automatically compiled and the object code (C#, in .NET) is generated obtaining an executable application. In protoBOM, the user constructs Decision Support Systems in a simpler way by using the ontologies of the diagnosis and the application domains by means of Domain Specific Languages. The interfaces will be closer to the problem domain, which will facilitate user interaction in a manner simple and intuitive.

In order to use components that are developed for a domain, domain knowledge is required. If the default relations in a domain are offered by a framework, this can be a starting point for the application engineer as an important kind of domain knowledge. A generic design for creating and saving a domain is implemented in this thesis. This approach starts with creating a domain from components and relations among these components. The relations and components are saved once and used several times. In addition, this generic design helps for code generation by using components. A framework for this design is implemented and applied for GIS domain. A basic code generation approach is also implemented in this framework for demonstration purposes. This framework can be used by domain engineers in order to create a domain and by application engineers to develop custom applications. It has the ability to offer default relations and helps creating new relations between components. Parameters and sequence of function calls can be defined by using a GUI. All the relations including default and userdefined ones can be used for code generation. COSECASE, which offers a tool for component-oriented design is extended with domain operations such as creating domain, saving domain, loading domain, and generating domain code. As the starting point, domain analysis for GIS domain is completed to define the domain. Then the components that have been implemented for GIS domain and relations between these components are saved within the framework. Moreover, some basic applications are generated by using this framework in the GIS domain. Also a sample domain is created to prove that our approach can be applied to any domain. The relations in this sample domain are saved in the framework and same basic applications are generated.

<p>software product line is a set of software-intensive systems that share a common, managed set of features satisfying the specificneeds of a particular market segment or mission. The main attractive part of SPL is developing a set of common assets which includes requirements, design, test plans, test cases, reusable software components and other artifacts. Tools for the development of softwareproduct line are very few in number. The purpose of these tools is to support the creation, maintenance and using different versions ofproduct line artifacts. This requires a development environment that supports the management of assets and product development,processes and sharing of assets among different products.</p><p>The objective of this master thesis is to investigate the available tools which support Software Product Line process and itsdevelopment phases. The work is carried out in two steps, in the first step available Software Product Line tools are explored and a list of tools is prepared, managed and a brief introduction of each tool is presented. The tools are classified into different categoriesaccording to their usage, relation between the tools is established for better organization and understanding. In the second step, two tools Pure::variant and MetaEdit+ are selected and the quality factors such as Usability, Performance, Reliability, MemoryConsumption and Capacity are evaluated.</p>

A software product line is a set of software-intensive systems that share a common, managed set of features satisfying the specificneeds of a particular market segment or mission. The main attractive part of SPL is developing a set of common assets which includes requirements, design, test plans, test cases, reusable software components and other artifacts. Tools for the development of softwareproduct line are very few in number. The purpose of these tools is to support the creation, maintenance and using different versions ofproduct line artifacts. This requires a development environment that supports the management of assets and product development,processes and sharing of assets among different products. The objective of this master thesis is to investigate the available tools which support Software Product Line process and itsdevelopment phases. The work is carried out in two steps, in the first step available Software Product Line tools are explored and a list of tools is prepared, managed and a brief introduction of each tool is presented. The tools are classified into different categoriesaccording to their usage, relation between the tools is established for better organization and understanding. In the second step, two tools Pure::variant and MetaEdit+ are selected and the quality factors such as Usability, Performance, Reliability, MemoryConsumption and Capacity are evaluated.

A Component Oriented Software Engineering (COSE) modeling environment is enhanced with the capability to import executable components and deliver applications through their composition. For this purpose, an interface layer that utilizes JAR libraries as components has been developed. Also, Domain Engineering process has been applied to Geographical Information Systems (GIS) domain and utilized towards converting the environment to a development framework. The interface layer imports JAR libraries into the COSECASE tool, which is a graphical tool supporting COSE approach and COSE Modeling Language (COSEML). As a result, systems can be designed using abstractions and then implemented by corresponding deployed components. Imported code is made available to the COSECASE environment through this interface layer. Also, Domain Analysis, Domain Design, and Domain Implementation phases of Domain Engineering process have been applied to the GIS domain. Components developed in this Domain Implementation phase have been imported into COSECASE. A simple GIS application has been designed and generated through the interface layer of COSECASE for demonstration purposes.