Most current machine vision systems for industrial inspection were developed with one specific task in mind. Due to the requirement for real-time operation, these systems are typically implemented in special purpose hardware that performs very specific operations. Hence, these systems inflexible in the sense that they cannot easily be adapted to other applications. However, current trends in computer technology suggests that low-cost general-purpose computers will be available in the very near future that are fast enough to meet the speed requirements of many industrial inspection problems. If this low-cost computing power is to be effectively utilized on industrial inspection problems, more general-purpose vision systems must be developed, vision systems that can be easily adapted to a variety of applications. Unfortunately, little research has gone into creating such general-purpose industrial inspection systems. In this dissertation, a general vision system framework has been developed that can be easily adapted to a variety of industrial web inspection problems. The objective of this system is to automatically locate and identify "defects" on the surface of the material being inspected. This framework is designed to be robust, to be flexible, and to be as computationally simple as possible. To assure robustness this framework employs a combined strategy of top-down and bottom-up control, hierarchical defect models, and uncertain reasoning methods. To make this framework flexible, a modular Blackboard framework is employed. To minimize computational complexity the system incorporates a simple multi-thresholding segmentation scheme, a fuzzy logic focus of attention mechanism for scene analysis operations, and a partitioning of knowledge that allows concurrent parallel processing during recognition. Based on the proposed vision system framework, a computer vision system for automated lumber grading has been developed. The purpose of this vision system is to locate and identify grading defects on rough hardwood lumber in a species independent manner. This problem seems to represent one of the more difficult and complex web inspection problems. The system has been tested on approximately 100 boards from several different species. Three different methods for performing label verification were tested and compared. These are a rule-based approach, a k-nearest neighbor approach, and a neural network approach. The results of these tests together with other considerations suggest that the neural network approach is the better choice and hence is the one selected for use in the vision system framework. Also, a new back-propagation learning algorithm using a steep activation function was developed that is much faster and more stable than the standard back-propagation learning algorithm. This algorithm was designed to speed the learning process involved in training a neural network to do label verification. However this algorithm seems to have general applicability. / Ph. D.

This thesis presents two applications of spread spectrum technology to very small aperture terminal (VSAT) satellite communication networks. It describes two spread spectrum multiple access systems which use a form of noncoherent M-ary FSK (MFSK) as the primary modulation and analyzes their throughput. The analysis considers such factors as satellite power constraints and adjacent satellite interference. It considers the effect of onâ board processing on the multiple access efficiency and investigates the feasibility of overlaying low data rate spread spectrum signals on existing satellite traffic as a form of frequency reuse. / Master of Science

Thesis (PhD (Pathology. Medical Microbiology))--University of Stellenbosch, 2009. / ENGLISH ABSTRACT: Due to modern high-throughput technologies, large numbers of compounds are produced by parallel synthesis and combinatorial chemistry. The pharmaceutical industry therefore requires rapid and accurate methods to screen new drugs leads for membrane permeability potential in the early stages of drug discovery. Around 50 % of all investigational new drugs fail in pre-clinical and clinical phases of development due to inadequate absorption/permeation, distribution, metabolism, excretion and/or unacceptable toxicity. This may be decreased by applying in vitro screening methods early in the discovery process. Reliable in vitro models can be applied to determine permeation of the test compounds, which will help avoid the wasting of valuable resources for the development of drugs that are destined to fail in preclinical and clinical phases due to insufficient permeability properties. It is important to decide as early as possible on the most promising compound and physical formulation for the intended route of administration. With awareness of the increasing importance of in vitro models in the investigations of the permeability properties of drug compounds, this research project was specifically devoted to determine the suitability of our in vitro model to evaluate and predict drug permeability. A continuous flow-through diffusion system was employed to evaluate the permeability of nine different compounds/drugs with different chemical properties, across three biological membranes. The biological membranes chosen for the present study were human vaginal mucosa, human skin tissue and human small intestine mucosa. The continuous flow-through diffusion system was furthermore utilised to investigate the effects of de-epithelialisation of mucosal surfaces, chemical enhancers, temperature, permeant concentration and formulation on the permeability of the test compounds/drugs. The in vitro permeability information and data from the flow-through diffusion model were compared to in vitro and in vivo literature studies and drug profile. An in vitro model that is able to reliably predict in vivo data will shorten the drug development period, economise resources and may potentially lead to improved product quality. In this thesis research results are reported on the permeability of the mentioned biological membranes to the various chemical markers, including anti-HIV (human immunodeficiency virus) drugs. The permeability studies will be discussed in three sections: vaginal mucosa, skin tissue, small intestine mucosa. The results of the vaginal permeability studies showed that the three peptides (MEA- 5, MDY-19 and PCI) readily penetrated the vaginal mucosa. MDY-19 had a higher flux rate than MEA-5, commensurate with its smaller molecular size (weight). The surfactant enhanced the flux rate of MDY-19 approximately 1.3 times and decreased the lag time of the peptide. Removal of the vaginal epithelium increased the flux rates of the peptides across the mucosa and may have implications for a more rapid uptake of these and other microbicides in vivo. The permeability of 1 mM MDY-19 and PCI at 37 °C were significantly (p<0.05) higher than at 20 °C. At 37 °C the AUCs of the overall mean flux values of MDY-19 and PCI increased with concentration according to well-established diffusion theory. The experiments on the permeability of different terbinafine hydrochloride formulations through human skin demonstrated that the terbinafine hydrochloride formulations used in this study, readily diffused into the skin tissue. However, no flux values for any of the terbinafine hydrochloride formulations through the skin into the acceptor fluid were found. The mean terbinafine concentrations in the skin after 24 h exposure to the three commercial, terbinafine hydrochloride formulations were 3.589, 1.590 and 4.219 μg/ml respectively. The mean terbinafine concentration in the skin exposed to the 10 mg/ml PBS/Methanol solution was higher than those from the three commercial formulations. The results of the temperature study demonstrated that an increase of 5 ºC caused a significant increase in flux values of tritiated water across skin. The flux values for tritiated water across skin at 37 ºC were on average double those at a temperature of 32 ºC. The permeability of excised human small intestine mucosa to different oral dosage drugs was investigated over a 24 h period. The four drugs selected were zidovudine, propranolol hydrochloride, didanosine and enalapril maleate. They were selected as representative model compounds of drug classes 1 (high solubility, high permeability) and 3 (high solubility, low permeability) according to the Biopharmaceutics Classification System. The flux rates of the four chosen test drugs were influenced by the length of the experiment. Between the time periods 2-4 h and 4-6 h, zidovudine’s mean flux values across small intestine tissue were respectively 1.8 and 2.0 times higher than didanosine and 2.3 and 2.2 times higher than enalapril. Propranolol’s mean flux values were respectively 1.2 and 1.4 times higher than didanosine and 1.6 higher than enalapril during both the 2-4 and 4-6 h time periods. Between both the time periods 2-4 and 4-6 h AZT’s mean flux values were 1.4 times higher than propranolol and didanosine’s mean flux values were respectively 1.3 and 1.1 times higher than enalapril during the mentioned time periods. Class 1 drugs showed a significantly higher flux rate across the jejunal mucosa compared to the class 3 drugs and these results are in line with their Biopharmaceutics Classification System classification. The in vitro model has proved to be reliable to predict permeability of class 1 and 3 drugs and also showed correlation with human in vivo data. It seems that the in vitro flow-through diffusion model used in the present study have the potential to overcome some of the problems and limitations demonstrated by other in vitro techniques and may potentially serve as a future tool for pharmaceutical companies to predict the diffusion characteristics of new drugs and different formulations, across different biological membranes. Furthermore, it may serve as a prospective method for assessing the bioequivalence of alternative (generic) vehicles or formulations containing the same drug/compound. / AFRIKAANSE OPSOMMING: As gevolg van moderne hoë spoed tegnologie kan groot hoeveelhede middels vervaardig word deur ooreenkomende sintese en kombinasieleer chemie. Die farmaseutiese industrie benodig dus vinnige en akkurate metodes om nuwe geneesmiddels te evalueer t.o.v. membraan deurlaatbaarheid. Hierdie evaluasie moet verkieslik so vroeg moontlik in die geneesmiddel se ontwikkelingsproses geskied. Ongeveer 50 % van alle potensiële geneesmiddels misluk in pre-kliniese en kliniese fases van geneesmiddelontwikkeling. Die mislukte pogings kan toegskryf word aan onvoldoende absorbsie/deurlaatbaarheid, distribusie, metabolisme, ekskresie en/of onaanvaarbare middel toksisiteit. Dit is daarom belangrik om so vroeg moontlik in die geneesmiddelontwikkelingsproses te besluit op die mees belowende middel, asook die geskikte formulasie vir die spesifieke roete van toediening van die middel. Die farmaseutiese industrie benodig tans in vitro modelle met die potensiaal om die deurlaatbaarheid van geneesmiddels te bepaal en te voorspel. Betroubare in vitro modelle kan aangewend word om die deurlaatbaarheid van potensiële geneesmiddels te toets. Sodoende sal die onnodige uitgawes op die ontwikkkeling van geneesmiddels wat in elk geval later gaan faal in pre-kliniese en kliniese fases van geneesmiddelproewe a.g.v. deurlaatbaarheidseienskappe, vermy word. Hierdie navorsingsprojek was dus spesifiek onderneem om die waarde en toepaslikheid van ‘n in vitro deurlopende-vloei perfusie model te ondersoek. Die model se potensiaal om geneesmiddels se deurlaatbaarheid en absorpsie te voorspel was geëvalueer. Die deurlopende-vloei perfusie apparaat was gebruik om die deurlaatbaarheidsvloede van drie verskillende biologiese membrane t.o.v. nege chemiese stowwe (MEA-5, MDY-19, PCI, terbinafien hidrochloried, getritieerde water, zidovudien, propranolol, hidrochloried, didanosien, enalapril maleaat) te bepaal. Die drie biologiese membrane wat gebruik was, was vaginale weefsel, vel en klein intestinale weefsel. Al drie weefsel tipes was van menslike oorsprong. Die deurlopende-vloei perfusie apparaat was ook gebruik om die effek wat verwydering van die mukosa se epiteellaag op deurlaatbaarheidsvloede het, te ondersoek. Verder was navorsing gedoen op die effek van temperatuur en die konsentrasie en formulasie van die toetsmiddels op hulle diffusie vloedwaardes. Daar was ook gekyk na die invloed van ander chemiese stowwe op die toetsmiddels se diffusie vloedwaardes. Die in vitro deurlaatbaarheidsinformasie en -gegewens was vergelyk met ander in vitro en in vivo literatuurstudies en geneesmiddel databasisse. ‘n In vitro model wat in staat is om in vivo resultate betroubaar te voorspel, het die potensiaal om die tyd wat dit neem om geneesmiddels te ontwikkel, te verkort, finansiële uitgawes te besnoei en om geneesmiddelkwaliteit te verseker. In die tesis word dan die resultate gerapporteer van die deurlaatbaarheidsvloede van die verskillende tipes weefsel ten op sigte van verskeie chemiese stowwe, insluitende anti-MIV (menslike immuniteitsgebreksvirus) middels. Die deurlaatbaarheidstudies word bespreek in drie afdelings: vaginale mukosa, vel en klein intestinale mukosa. Die resultate van die deurlaatbaarheidstudies op die vaginale weefsel dui daarop dat die drie peptiede (MEA-5, MDY-19 and PCI) die vaginale mukosa goed penetreer. Soos verwag, het MDY-19 hoër diffusie vloedwaardes as MEA-5 gehad. Dit kan toegeskryf word aan MDY-19 se kleiner molekulere grootte (gewig). Surfaktant het die diffusie vloedwaardes van MDY-19 1.3 keer vergroot en het ook die tyd na vaste vlak verminder. Die verwydering van die vaginale epiteel het die diffusie vloedwaardes van die peptiede verhoog en mag dus dui op die vinniger opname van peptiede en moontlike ander mikrobisiede in vivo, wanneer die belyning van die epiteel onderbreek. Die deurlaatbaarheid van 1 mM MDY-19 en PCI by 37 °C was satisties beduidend (p<0.05) hoer as teem 20 °C. Die area onder die kurwe (AOK) van die gemiddelde vloedwaardes van MDY-19 en PCI by 37 °C, het toegeneem met ‘n toename in die konsentrasie van hierdie peptiede. Die toename vloedwaardes ondersteun dus die alombekende diffusie teorie. Die transdermale diffusie eksperimente van verskillende terbinafien formulasies het getoon dat terbinafien geredelik vrygestel word vanuit hierdie formulasies na die vel. Geen terbinafien vloedwaardes, van enige van die formulasies, was egter gevind in die ontvangselle van die deurlopende-vloei perfusie apparaat nie. Die gemiddelde terbinafien konsentrasies in die vel na 24 h se blootstelling aan drie kommersiële terbinafien hidrochloried formulasies was onderskeidelik 3.589, 1.590 en 4.219 μg/ml. Die gemiddelde terbinafien konsentrasie in die vel wat aan 10 mg/ml PBS/metanol blootgestel was, was hoër as die konsentrasies in die vel wat aan die drie kommersiële formulasies blootgestel was. Die resultate van die temperatuurstudie op vel het aangetoon dat ‘n temperatuur toename van 5 ºC ‘n statisties beduidende toename in vloedwaardes van getritieerde water oor vel veroorsaak. Die vloedwaardes van die getritieerde water oor vel teen ‘n temperatuur van 37 ºC was gemiddeld dubbeld so veel as teen 32 ºC. Die deurlaatbaarheidsvloede van klein intestinale mukosa ten opsigte van verskillende geneesmiddels (wat oraal toegedien word) was ondersoek gedurende ‘n 24 h eksperiment. Die vier geneesmiddels wat gebruik was, was zidovudine, propranolol hidrochloried, didanosien en enalapril maleaat. Hierdie geneesmiddels is verteenwoordigers van die Biofarmaseutiese Klassifikasie Sisteem se klas 1 (hoë oplosbaarheid, hoë deurlaatbaarheid) en klas 3 (hoë oplosbaarheid, lae deurlaatbaarheid) geneesmiddels. Die vloedwaardes van die vier geneesmiddels het gewissel na aanleiding van die tydsverloop in die eksperiment. Zidovudien se gemiddelde vloedwaardes tussen 2-4 en 4-6 h was onderskeidelik 1.8 en 2.0 keer hoër as didanosien se gemiddelde vloedwaardes vir hierdie tyd periodes en onderskeidelik 2.3 en 2.2 keer hoër as enalapril se gemiddelde vloedwaardes. Tydens hierdie selfde periodes was propranolol se gemiddelde vloedwaardes 1.2 en 1.4 keer hoër as didanosien en vir beide periods 1.6 keer hoër as enalapril se gemiddelde vloedwaardes. Gedurende beide genoemde tyd periodes was zidovudien se gemiddelde vloedwaardes 1.4 keer hoer as propranolol en didanosien se gemiddelde vloedwaardes was onderskeidelik 1.3 en 1.1 keer hoër as enalapril tydens 2-4 en 4-6 h. Die klas 1 geneesmiddels het statisties beduidende hoër vloedwaardes gehad as die klas 3 geneesmiddels. Hierdie resultate stem ooreen met die geneesmiddels se Biofarmaseutiese Klassifikasie Sisteem klassifikasie. Dit wil dus voorkom asof die in vitro model wat gebruik was in die studie, gebruik kan word om die deurlaatbaarheidsvloede van klas 1 en 3 te voorspel. Die resultate van hierdie studie stem ooreen met ander in vivo studies. Dit wil voorkom asof die in vitro deurlopende-vloei perfusie apparaat die potensiaal het om sommige van die probleme en tekortkominge van ander in vitro modelle te oorkom en dat dit moontlik die potensiaal het om die diffusie-eienskappe van nuwe geneesmiddels en verskillende formulasies oor verskillende biologiese membrane te voorspel. Die model kan verder moontlik dien as ‘n potensiële toestel om biogelykbaarheid van alternatiewe (generiese) formulasies, wat dieselfde geneesmiddel/chemiese stof bevat, te bepaal.

Please see the English Abstract / In the 21st century, the globalization movement to multinational corporations is an inevitable process to maintain the continuous business growth. Asia, in particular, has drawn all the attention of multinational corporations worldwide and is considered as the region of the century. This research is designed to study the Asian regional operations of a multinational corporate in semiconductor equipment industry. In response to the regional customers demand, the regional competition, and the regional operations cost reduction, the case company has strategically established regional operations centers in Asia, covering the aspects of technical support, technical training, parts logistics, parts sourcing and repairing, as well as service outsourcing. This study found that the outstanding regional operations strategy plays a key role in the industrial competition and the overall operational excellence. The service enhancement through the technical support and spares sourcing can directly benefit the IC manufacturing customers and reword to the cost reduction of the regional operations. The studied case company clearly can be a benchmark of the regional operations practices for semiconductor equipment industry as well as for other related industries. Furthermore, the objective of this research is to provide useful suggestions that may help the firms in the industry on their future regional operations strategies setting as well as offer the academic researchers with a good case study of the development of regional operations in Asia.

Major changes that emphasise the importance of a balanced work and family life have occurred within organisations. Inability to manage this integration between the work and home domains can affect the performance of organisations and the wellbeing of their employees. In order to measure work-home interaction and wellbeing, it is important to use valid, equivalent and reliable instruments. However, there is a lack of empirical research when investigating work-home interaction, burnout and work engagement in the earthmoving equipment industry in South Africa. Furthermore, the earthmoving equipment industry is a multicultural environment and construct equivalence across subgroups therefore becomes important when measuring work-home interaction, burnout and work engagement across different cultural or language groups. It also seems relevant to consider differences in the work-home interaction and work wellness levels between important demographic groups in the earthmoving equipment industry. It appears as if burnout and engagement can be seen as part of the total wellness continuum; and that job characteristics may be related to burnout and engagement through negative and positive work-home interaction. However, little information was found that included these factors in a structural model for the earthmoving equipment industry. The objectives of this research were to test the psychometric properties of the Survey Work- Home Interaction - Nijmegen (SWING), the Maslach Burnout Inventory - General Survey (MBI-GS) and the Utrecht Work Engagement Scale (UWES); to determine if various demographic groups differ with regard to work-home interaction and wellbeing; and to test a structural model that includes job characteristics, work-home interaction and wellbeing for employees in the earthmoving industry. A cross-sectional survey design was used. Random samples (n = 528) were taken from employees in the earthmoving equipment industry in Gauteng, the Limpopo Province, Mpumalanga, the Northern Cape, the Western Cape, the Eastern Cape, Kwa-Zulu Natal and the North West Province. Structural equation modelling confirmed a four-factor model of work-home interaction which measures negative work-home interference, positive work-home interference, negative homework interference and positive home-work interference. This factor structure was equivalent across language, ethnicity, gender, education, marital status and parental status. All four factors were reliable. The participants reported more negative WHI than negative HWI, and more positive HWI than positive WHI. It was found that statistically significant differences that are based on age, gender, language, ethnicity, a partner's contribution to household income and the different business units exist between the demographic groups. The results confirmed a four-factor structure of burnout (exhaustion, cognitive weariness, cynicism and professional efficacy) and a two-factor structure of work engagement (including vigour and dedication). These structures were equivalent across language and education groups, and all scales were reliable. SEM analyses supported a two-factor structure for the wellness construct, consisting of burnout (exhaustion, cognitive weariness and cynicism) and engagement (vigour, dedication and professional efficacy), which was equivalent for the language and education groups. Statistically significant differences that are based on age, gender, language and the different business units were found between the demographic groups. Structural equation modelling showed that job demands are associated with negative WHI and consequently with burnout, providing support for a full-mediation effect of negative WHI. Job resources were associated with negative WHI and consequently with burnout, providing support for partial mediation of negative WHI between job resources and burnout. Job resources were also associated with positive WHI and consequently with engagement, providing support for partial mediation of positive WHI between job resources and engagement. Recommendations for the organisation and future research were made. / Thesis (Ph.D. (Industrial Psychology))--North-West University, Potchefstroom Campus, 2007.

Abstract not available

As organisations try to emerge from the recent economic downturn, they attempt to enter different markets to decrease their dependency on their core market. Due to high costs in R&amp;D and the risk of failure, organisations try to sell the core components of their products to business partners who can incorporate these components into their own offering. Using a qualitative research method, we studied the case of TACHI as a player in the construction equipment industry. The purpose of the research was to find factors for maintaining successful business partnerships within this industry and also the role of co- branding in these business partnerships. After analysing the results of our study and reflecting on the theoretical framework, we concluded that operational compatibility, and commitment and trust were considered as the key factors that were most important in making business partnerships work successfully. Interestingly, players in the construction equipment industry do not consider co-branding as a strategy for entering new markets. However, we discovered a new phenomenon, which is informal branding, and we recommend this as a topic for future research.

In an ever-changing world, people are constantly faced with the challenge of simultaneously managing multiple roles in their work as well as their home-sphere. It therefore becomes increasingly important to maintain a balance in these two life spheres. Unfortunately, a gap exists between the positive and negative side of work-home balance as most research focuses on the negative side. Recently, a much needed instrument was develop in the Netherlands, namely the Survey Work-Home Interaction - Nijmegen (SWING), which measures both the direction of influence (work→home and vice versa) and the quality of influence (negative vs. positive). The objectives of this study were to validate the Survey Work-Home Interaction - Nijmegen (SWING) for workers of the earthmoving equipment industry in a South African context, to determine its construct equivalence and bias for different language groups, and to determine differences regarding work-home interaction between different demographic groups. A cross-sectional survey design was used. Random samples (n = 330) were taken of workers in the earthmoving equipment industry across South Africa. The SWING and a biographical questionnaire were administered. Item bias analyses, exploratory factor analysis, Cronbach alpha coefficients, MANOVAs, ANOVAs and T-tests were used to analyse the data. Exploratory factor analysis showed that the SWING consists of four factors, namely Negative Work-Home Interference, Negative Home-Work Interference, Positive Work-Home Interference and Positive Home-Work Interference. All four factors showed acceptable internal consistencies. No evidence was found for uniform or non-uniform bias of the items of the SWING for different language groups. Exploratory factor analysis with target rotations confirmed the construct equivalence of the work-home interface construct. There were also no differences regarding work-home interaction between different demographic groups, except for a practically significant difference (medium effect) between males and females with respect to negative Work-Home Interaction levels. Recommendations were made for further research. / Thesis (M.Com. (Industrial Psychology))--North-West University, Potchefstroom Campus, 2005.

In an ever-changing world, people are constantly faced with the challenge of simultaneously managing multiple roles in their work as well as their home-sphere. It therefore becomes increasingly important to maintain a balance in these two life spheres. Unfortunately, a gap exists between the positive and negative side of work-home balance as most research focuses on the negative side. Recently, a much needed instrument was develop in the Netherlands, namely the Survey Work-Home Interaction - Nijmegen (SWING), which measures both the direction of influence (work→home and vice versa) and the quality of influence (negative vs. positive). The objectives of this study were to validate the Survey Work-Home Interaction - Nijmegen (SWING) for workers of the earthmoving equipment industry in a South African context, to determine its construct equivalence and bias for different language groups, and to determine differences regarding work-home interaction between different demographic groups. A cross-sectional survey design was used. Random samples (n = 330) were taken of workers in the earthmoving equipment industry across South Africa. The SWING and a biographical questionnaire were administered. Item bias analyses, exploratory factor analysis, Cronbach alpha coefficients, MANOVAs, ANOVAs and T-tests were used to analyse the data. Exploratory factor analysis showed that the SWING consists of four factors, namely Negative Work-Home Interference, Negative Home-Work Interference, Positive Work-Home Interference and Positive Home-Work Interference. All four factors showed acceptable internal consistencies. No evidence was found for uniform or non-uniform bias of the items of the SWING for different language groups. Exploratory factor analysis with target rotations confirmed the construct equivalence of the work-home interface construct. There were also no differences regarding work-home interaction between different demographic groups, except for a practically significant difference (medium effect) between males and females with respect to negative Work-Home Interaction levels. Recommendations were made for further research. / Thesis (M.Com. (Industrial Psychology))--North-West University, Potchefstroom Campus, 2005.

Major changes that emphasise the importance of a balanced work and family life have occurred within organisations. Inability to manage this integration between the work and home domains can affect the performance of organisations and the wellbeing of their employees. In order to measure work-home interaction and wellbeing, it is important to use valid, equivalent and reliable instruments. However, there is a lack of empirical research when investigating work-home interaction, burnout and work engagement in the earthmoving equipment industry in South Africa. Furthermore, the earthmoving equipment industry is a multicultural environment and construct equivalence across subgroups therefore becomes important when measuring work-home interaction, burnout and work engagement across different cultural or language groups. It also seems relevant to consider differences in the work-home interaction and work wellness levels between important demographic groups in the earthmoving equipment industry. It appears as if burnout and engagement can be seen as part of the total wellness continuum; and that job characteristics may be related to burnout and engagement through negative and positive work-home interaction. However, little information was found that included these factors in a structural model for the earthmoving equipment industry. The objectives of this research were to test the psychometric properties of the Survey Work- Home Interaction - Nijmegen (SWING), the Maslach Burnout Inventory - General Survey (MBI-GS) and the Utrecht Work Engagement Scale (UWES); to determine if various demographic groups differ with regard to work-home interaction and wellbeing; and to test a structural model that includes job characteristics, work-home interaction and wellbeing for employees in the earthmoving industry. A cross-sectional survey design was used. Random samples (n = 528) were taken from employees in the earthmoving equipment industry in Gauteng, the Limpopo Province, Mpumalanga, the Northern Cape, the Western Cape, the Eastern Cape, Kwa-Zulu Natal and the North West Province. Structural equation modelling confirmed a four-factor model of work-home interaction which measures negative work-home interference, positive work-home interference, negative homework interference and positive home-work interference. This factor structure was equivalent across language, ethnicity, gender, education, marital status and parental status. All four factors were reliable. The participants reported more negative WHI than negative HWI, and more positive HWI than positive WHI. It was found that statistically significant differences that are based on age, gender, language, ethnicity, a partner's contribution to household income and the different business units exist between the demographic groups. The results confirmed a four-factor structure of burnout (exhaustion, cognitive weariness, cynicism and professional efficacy) and a two-factor structure of work engagement (including vigour and dedication). These structures were equivalent across language and education groups, and all scales were reliable. SEM analyses supported a two-factor structure for the wellness construct, consisting of burnout (exhaustion, cognitive weariness and cynicism) and engagement (vigour, dedication and professional efficacy), which was equivalent for the language and education groups. Statistically significant differences that are based on age, gender, language and the different business units were found between the demographic groups. Structural equation modelling showed that job demands are associated with negative WHI and consequently with burnout, providing support for a full-mediation effect of negative WHI. Job resources were associated with negative WHI and consequently with burnout, providing support for partial mediation of negative WHI between job resources and burnout. Job resources were also associated with positive WHI and consequently with engagement, providing support for partial mediation of positive WHI between job resources and engagement. Recommendations for the organisation and future research were made. / Thesis (Ph.D. (Industrial Psychology))--North-West University, Potchefstroom Campus, 2007.