This research study provides a historical orientation of the development of polygraphy in the United States of America and then focuses on the development of the local South African polygraph industry and its utilisation by the private sector and various government institutions. The historical orientation and contextualisation of polygraphy is based on information accessed through the electronic medium, acknowledged polygraph publications and first-hand information collected from individuals in the local polygraph fraternity. The phases of the polygraph testing process, types of polygraph examinations and the various testing formats are defined, as well as the role of polygraphy to screen personnel and investigate crime. Aspects such as the polygraph training, the local polygraph associations and the legal status of polygraphy in terms of South African law are examined. The study explores the South African polygraph fraternity in general, but focussed in detail on the activities of polygraphists and polygraph companies operating in the Limpopo Province, South Africa. The utilisation and development of polygraphy in the Limpopo Province, as well as various operational issues are explored as a case study. The role of polygraph testing to screen staff and to prevent crime in the workplace, as well as its role as an invaluable tool to investigate crime and resolve disputes by clients in the Limpopo Province, are examined. One thousand polygraph examinations were analysed for this purpose, to gain a unique and novel insight into the circumstances, challenges and operational obstacles faced by polygraphists in the Limpopo Province. While this analysis did not provide groundbreaking scientific findings, it did provide new insight into the types of crimes committed, the industries targeted by criminals, the profile of examinees tested, and the nature and scope of the polygraph-testing requirements in the province. The potential for expanding the polygraph industry in the Limpopo Province is also considered. In conclusion, recommendations are made for the statutory regulation of the polygraph industry in South Africa, to ensure that ethical, operational and training standards are upheld. The importance of consolidating the local polygraph fraternity under one umbrella, in order to challenge and dispel uninformed opinions and myths concerning the use of polygraph testing, is also stresses. A proposal is also made concerning the indigenisation of current polygraph practises and polygraph training, to meet the unique conditions of Southern African. / Criminology and Security Science / (M.Tech) (Security management)

published_or_final_version / Medical Sciences / Master / Master of Medical Sciences

Malingering refers to the voluntary production of false or greatly exaggerated symptoms in pursuit of an obviously recognizable goal. Numerous studies have shown the psychological tests can detect persons faking various mental disorders; however, the majority of these are plagued by methodological flaws that seriously limit their validity and generalizability. The present study employed a contrasted-groups design that allowed for a rigorous test of the hypothesis that a battery of psychological tests can detect persons given a financial incentive to fake insanity or mental retardation. In addition to using two tests previously employed in simulation research (MMPI and Bender Gestalt), an instrument whose sole purpose is to differentiate malingerers from genuinely impaired adults was developed for validation in this study. This pen-and-paper test (the Malingering Scale) consists of 90 arithmetic, vocabulary, information and abstraction items, and requires 20 minutes to complete. One hundred male adults were divided into five groups of 20 subjects. Two groups consisted of genuinely impaired subjects (either mentally retarded or psychotic inpatients). The other three groups were drawn from a population of prison inmates. Two of the latter groups were offered a financial incentive for successful simulation of a mental disorder (either mental retardation or "insanity") while the fifth group consisted of inmates controls (answering honestly). The test battery was administered to all subjects and scored by examiners who were naive to the purpose of the study. A series of item analyses established the internal consistency of the Malingering Scale and identified those items which best differentiate malingerers from the genuinely impaired. These items were assembled into scoring keys for subjects faking each condition. All test scores were then entered into a series of discriminant function analyses which confirmed the hypothesis that the battery provided more powerful discrimination of subject groups than any single test. Overall, 84% of the subjects were accurately classified into their respective group, and 96% of subjects were correctly identified as either malingering or not malingering. The most powerful single instrument proved to be the Malingering Scale. Direction for future research, including the necessity for cross validation of the Malingering Scale, were discussed.

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This research study provides a historical orientation of the development of polygraphy in the United States of America and then focuses on the development of the local South African polygraph industry and its utilisation by the private sector and various government institutions. The historical orientation and contextualisation of polygraphy is based on information accessed through the electronic medium, acknowledged polygraph publications and first-hand information collected from individuals in the local polygraph fraternity. The phases of the polygraph testing process, types of polygraph examinations and the various testing formats are defined, as well as the role of polygraphy to screen personnel and investigate crime. Aspects such as the polygraph training, the local polygraph associations and the legal status of polygraphy in terms of South African law are examined. The study explores the South African polygraph fraternity in general, but focussed in detail on the activities of polygraphists and polygraph companies operating in the Limpopo Province, South Africa. The utilisation and development of polygraphy in the Limpopo Province, as well as various operational issues are explored as a case study. The role of polygraph testing to screen staff and to prevent crime in the workplace, as well as its role as an invaluable tool to investigate crime and resolve disputes by clients in the Limpopo Province, are examined. One thousand polygraph examinations were analysed for this purpose, to gain a unique and novel insight into the circumstances, challenges and operational obstacles faced by polygraphists in the Limpopo Province. While this analysis did not provide groundbreaking scientific findings, it did provide new insight into the types of crimes committed, the industries targeted by criminals, the profile of examinees tested, and the nature and scope of the polygraph-testing requirements in the province. The potential for expanding the polygraph industry in the Limpopo Province is also considered. In conclusion, recommendations are made for the statutory regulation of the polygraph industry in South Africa, to ensure that ethical, operational and training standards are upheld. The importance of consolidating the local polygraph fraternity under one umbrella, in order to challenge and dispel uninformed opinions and myths concerning the use of polygraph testing, is also stresses. A proposal is also made concerning the indigenisation of current polygraph practises and polygraph training, to meet the unique conditions of Southern African. / Criminology and Security Science / (M.Tech) (Security management)

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Metallized polypropylene film capacitors are prone to failure under high pulsed voltage and current waveforms. A set of specifications are given by the International Electrotechnical Commission (IEC) that defines the required performance characteristics of these capacitors. The proposed test setup is very involved and requires a skilled operator who is responsible for ensuring that the prescribed test conditions are accurately applied to the capacitor. Automated test and measurement equipment was developed to conduct these tests according to the IEC specifications. The test equipment generates large crest factor current discharge waveforms in the capacitor with peaks reaching 1000 A. A new method was also developed for measuring the rms value of these current waveforms using a low-end microcontroller, together with an inexpensive current transformer. The recommended IEC discharge circuit is powered by a switching power supply, utilizing feedback control, which also enables the rms current through the capacitor to be regulated. By automating the system, important responsibilities are isolated from the operator, allowing a less skilled person to effectively conduct the capacitor tests. / Prof. W.A. Cronje Prof. I.W. Hofsajer