The dynamic characteristics of engineered-to-order (ETO) environments are in conflict with the basic assumptions of Manufacturing Resource Planning (MRP) systems, which makes MRP based manufacturing planning systems fail to meet the needs of ETO companies. ETO environments are complex and require sophisticated planning techniques. In fact, the shortcomings of planning and scheduling systems are exacerbating the ability of ETO companies to reduce manufacturing cycle times. This thesis presents an overview of ETO environments and related manufacturing planning and scheduling systems. The reasons for the failure of present MRP systems to address ETO environments are discussed along with an analysis of the planning systems of real companies. A new framework for manufacturing planning and scheduling in ETO environments is proposed. It addresses the importance of coordinating planning and scheduling among engineering, material procurement and the shop floor. It incorporates finite capacity scheduling into MRP systems to overcome load fluctuations. It also has scheduling mechanisms to address the dynamic nature of ETO environments.

In the extrusion blow moulding process, the strength and weight of a hollow article, such as a bottle, is controlled by an open loop control process called parison programming. The article thickness is increased and decreased by opening and closing the gap of the annular die from which the parison is extruded. The die gap is regulated according to a gap-time profile which an operator determines during start up by trial and error. / An optical sensor has been developed which can measure the thickness profile of the parison on-line just prior to its enclosure in the mould. The device will help operators to program the gap-time profile for optimum use of plastic by providing rapid feedback on the formation of the parison. It also represents an important step toward the development of closed loop control for container thickness distribution. / The device determines thickness by striking the parison at an angle with a laser beam and measuring the separation between the beams that reflect from the outer and inner surfaces of the parison wall. A prototype was built and tested. The prototype uses three lasers at different angles and can make up to 250 point measurements during a one second scan. A personal computer uses specially developed software to reconstruct the profile of the parison wall from the raw data with an accuracy of $ pm$5%.

The careers of academic staff in South Africa - as in the rest of the world - are under tremendous pressure for various reasons, and a decline in the image and status associated with an academic career can even be observed. However, no academic institution can be totally successful without qualified and loyal academics. Higher education institutions - more than any other type of organisation - are dependent on the intellectual and creative abilities of academic staff, as well as their commitment, since it is difficult to replace their knowledge, skills and experience. These qualities can only be acquired over a long period of time and with experience. It is evident that there will be an increasing shortage of academic staff within South African higher education institutions in the future, due to factors such as more attractive options in other business sectors. If the career dilemmas of academic staff are not identified and addressed, the quality and sustainability of higher education institutions may be jeopardised. In view of the above-mentioned, the purpose of this study was to investigate the typical career dilemmas of academic staff during the early, middle and late career phases within a changing South African higher education institution. Aspects related to job dissatisfaction were used as indicators in this study in order to identify and explain career dilemmas. Career dilemmas are associated with high levels of job dissatisfaction and work stress, and imply aspects such as reduced commitment to the organisation, declining psychological and physical health, problematic interpersonal work relations and lower work quality. Lifespan and career development tasks during the different adult lifespan phases were therefore used in this regard to explain the phenomenon of career dilemmas further. The different aspects that influence the job satisfaction of academic staff in a changing higher education work environment were subsequently identified and discussed. In view of the nature of this study and the type of problem that was investigated, a qualitative research design was used. Ninety-three academic staff members were selected on the basis of age, gender and race from a higher education institution, by means of an occasional random sample. The data was obtained by means of a Delphi-process in order to identify the career dilemmas of academics during the early, middle and late career phases. The results obtained in this study indicate that academics generally experience the same career dilemmas, irrespective of the career phase they are in. The prominent career dilemmas of academics centre mostly on the absence of a performance evaluation system that correctly and equitably reflects their performance, input and responsibilities. Limited opportunities for promotion, as well as the absence of a clear set of criteria or guidelines according to which promotion takes place, were identified as a further significant dilemma. The absence of promotion criteria contributed towards the incidence of discrimination and double standards. Role overload and/or role conflict, as well as an inadequate financial remuneration structure, were regarded as prominent career dilemmas throughout. Academics also identified aspects indicating job insecurity and ineffective management as dilemmas. Certain forms of discrimination were also identified as career dilemmas by some black and female academics. Academics in the early career phase in particular regarded inadequate support in the performance of core activities - with specific reference to teaching and research - as a further significant career dilemma. The dominant career dilemmas of academics identified in this investigation show numerous similarities with the career dilemmas of academics identified in other national and international studies. The dilemma the academic career and higher education is probably facing is illustrated further by the fact that several of the academics employed at this institution indicated their uncertainty about continuing their careers at the institution concerned, and that several of them even gave strong indications that they will probably be leaving the institution. In order to effectively address the career dilemmas experienced by academics, higher education institutions will have to devote particular attention to establishing an effective performance management system that is easy to understand and implement, as well as transparent, equitable and fair. Promotion criteria must be spelled out clearly and applied consistently. Alternative career paths that accommodate individual preferences and abilities and create additional promotion opportunities may also be considered as a solution. Furthermore, it is important that remuneration for academics should be market-related and competitive. It must be ensured that junior colleagues receive adequate support with regard to teaching, research and community service by means of training opportunities, regular feedback, mentorshipâs and counselling that addresses identified needs. Finally, it is important that academics functioning in management positions possess appropriate management qualifications and receive the necessary training and support to enable them to effectively perform their management role. The effective management of diversity and cultural sensitisation should also be addressed on a continuous basis.

Not available

Unethical behaviour is a general tendency in the current work situation where there appears to be a decrease in ethical behaviour on a national as well as international level within organisations. Unethical behaviour including bribery, nepotism, fraud and corruption are also found in South African organisations. Unethical behaviour can have financial consequences and market related risks for organisations, and can lead to negative media exposure. Apart from the negative consequences which unethical behaviour holds for organisations, unethical behaviour also leads to low morale under employees and a high employee turnover. The negative consequences which unethical behaviour holds for organisations, as well as the South African economy, necessitates a focus on factors which may have an influence on ethical behaviour, and specifically work ethics. Current research supports a person-situation-interaction approach to ethical decision-making where both individual and situational factors influence the decisions that the individual makes. Regarding individual factors, researchers indicate that the individualâs ethical decision-making philosophy influences the manner in which ethical problems are managed and behavioral decisions are made. It is apparent from the literature that different authors identified different philosophical approaches regarding ethical decision-making. There is however no model in existence which integrates these approaches. Furthermore, it also became apparent from the literature that there is a need within the South African context for the development of a reliable and valid work ethics questionnaire which determines individualsâ ethical decision-making approaches as well as their level of ethical behaviour. The purpose of this study was therefore twofold: Firstly a holistic philosophical model of ethical decision-making was developed. The model integrated the following six philosophical approaches regarding ethical decision-making, namely the rule-bound approach; the consequensialistic approach; the rule-bound consequensialistic approach; the virtue approach; the social justice approach and relativism. Secondly a work ethics questionnaire (Work Convictions Questionnaire) (WCQ), which was administered upon a sample of five hundred and twenty four respondents, was developed. Item analysis and selection of items for the final questionnaire was performed by use of exploratory and confirmatory factor analysis. The following conclusions regarding objective 1 and objective 2 of the WCQ were reached from the statistical analysis. Objective 1 (Scale A): The determination of the individualâs level of ethical behaviour Scale A possesses a satisfactory content reliability. Furthermore, it is apparent that with regards to the validity (construct validity), the construct, level of ethical behaviour is well defined. Objective 2 (Scale B): Identification of the philosophical approaches that are followed during ethical decision-making Regarding the six philosophical approaches regarding ethical decisionmaking identified from the literature, one dimensionality was primarily suggested for the approaches. It is apparent from the statistical analyses that the six approaches each exhibit a satisfactory content reliability. Furthermore, it is apparent that with regards to the validity (construct validity), the concept philosophical approaches regarding ethical decision-making (six-factor structure) is well defined and that the six factor structure exhibits a good fit and a stable measuring model. Hereafter all two hundred and fifteen items were subjected to exploratory factor analysis without suggestion of any previously identified factor structure. Thereafter confirmatory factor analysis was applied to the factor structure. Three factors emerged, namely the rule bound, consequensialistic and discretionary approaches. The three approaches each exhibited a satisfactory content reliability. Furthermore, it is apparent that with regards to the validity (construct validity), the concept philosophical approaches regarding ethical decision-making (three-factor structure) is well defined and that the three-factor structure exhibits a good fit and stable measurement model. Therefore the six-factor structure or the alternative three-factor structure can be utilised. The important value of the study stems from the fact that it addresses the need for a reliable and valid work ethics questionnaire for the South African context. This measuring instrument not only provides an indication of the individualâs level of ethical behaviour, but also the approach followed during ethical decision-making.

Research has shown that staff members of call centres are experiencing high levels of job stress due to the demands of their jobs. Employees frequently have no control over their work environment and external factors that affect their performance and job satisfaction. They could, however, develop and utilize internal resources, like specific personality factors that can enable them to manage their job stress more effectively. The aims of the study was to determine the levels of job stress and burnout of staff members of a call centre and to identify specific personality factors that could be valid predictors of the ability of employees of a call centre to manage job stress and burnout effectively. Several studies have focused on the relationship between personality, job stress and burnout, but the Big Five personality traits and resilience as predictors of job stress and burnout have not received adequate attention. Non-probability sampling and specifically accidental sampling was used in a call centre in Bloemfontein, South Africa. The call centre involved is an out-bound, debt collecting call centre, with clients in South Africa and neighbouring states. A total of 187 employees in the call centre were involved in the study. The respondents were mainly black, female, single, South Sotho, between 21 and 25 years of age, acquired a grade 12 qualification and have served for less than one year. The measuring instruments that were used, include the International Personality Item Pool, the Resilience Scale, the Maslach Burnout Inventory (Human Services Survey) and the Experience of Work and Life Circumstances Questionnaire. Multiple stepwise regression analysis was used as statistical technique to process the data. Respondents exhibited a high level of job stress, an average level of emotional exhaustion, a high level of depersonalization and a low level of personal accomplishment. A significant linear relationship was found between job stress and specific Big Five personality factors, namely emotional stability and openness to experience. A significant linear relationship was also identified between conscientiousness and specific dimensions of burnout, namely emotional exhaustion and depersonalization. Resilience and more specifically acceptance of self and life was also found to be a valid predictor of depersonalization, a dimension of burnout. Conscientiousness, agreeableness and resilience were found to be valid predictors of the personal accomplishment dimension of burnout. Future research in this regard should be done with a more representative sample of call centres in South Africa in order to generalize the results to call centres in general. The personality factors that have been identified in this study as valid predictors of the effective management of job stress and burnout could be used for purposes of selection and training in call centres.

QWL is a major issue for employees, and how organizations deal with this issue is of both academic and practical significance. QWL and its relationships with employeesâ mental health and performance became an explicit objective for many of the human resource policies in modern organizations. Although there is no formal definition of QWL, industrial psychologists and management scholars agree in general that QWL is a construct that deals with the well-being of employees and that QWL differs from job satisfaction. QWL variables are excellent indicators of whether or not employees are coping well with the stressors they are confronted with. Employees in the workplace should experience and exhibit high levels of mental health in order to ensure they cope effectively with the stressors they are being exposed to. According to the literature, QWL can produce a favourable work environment which is beneficial for developing and maintaining a good mental health. If this is the case, it could be assumed that QWL could be an important determinant and predictor of mental health. It would be of value to investigate which QWL variables play a significant role in determining mental health especially in service organizations where demands are high. The aim of the research was to determine whether QWL variables are predictors of employeesâ mental health in a service organization in the Free State. For the purpose of this study, one-hundred and forty two (142) employees working in a service organization in the Free State were selected. QWL was measured by the Leiden Quality of Work Life Questionnaire while mental health was measured by Warrâs Mental Health Measures, the General Health Questionnaire-28 (GHQ-28), the Satisfaction with Life Questionnaire and the Affectometer 2, which is a measure of general happiness. The multiple stepwise regression was used to predict which QWL variables affect employeesâ mental health in a service organization in the Free State. Due to the fact that non-probability sampling and more specifically accidental sampling was used, the results of this study could not be generalized. The sample of respondents consisted of more white respondents of which 58% were male respondents, which were married and having at least a matriculation qualification. The respondents exhibited a very high level of QWL except for work and time pressure, physical exertion, job insecurity and lack of meaningfulness. A high level of mental health was also exhibited by the respondents. The level of general health in terms of all the dimensions varied from low to very low. Furthermore, the respondents displayed a low level of satisfaction with life especially with material wealth. The respondentsâ level of general happiness (all the respective dimensions) was very low. Lack of meaningfulness, role ambiguity, social support (supervisor), work and time pressure, social support (colleague), skill discretion, hazardous exposure, job insecurity, physical exertion and decision latitude were identified as valid predictors of employeesâ mental health in the service organization. Further research regarding QWL as a predictor of mental health should be conducted since there were very few studies done in this regard. Based on the study a clear idea can be obtained as to which QWL variables are predictors of employeesâ mental health. The importance of acknowledging these factors aimed at improving employeesâ QWL and mental health in service organizations becomes apparent.

No description available.

No description available.

One of the most common industrial cold forging processes is cold heading of steel wire or rod to produce screws, bolts, nuts and rivets. The process is limited by a complicated interplay of many factors. The cold work (pre-drawing) is one of them. Although several investigations into the effects of pre-drawing on the formability of metals during cold heading processes have been conducted, so far no attention has been given to the numerical simulations of this phenomenon. The current work aims at examining effects of pre-drawing on formability during cold heading through numerical simulations. / Physical tests in the literature investigating the effects of pre-drawing on the formability of three metals are simulated using ABAQUS 6.4, with three successive FE models: the drawing model, the cutting model and the upsetting model. A new combined linear kinematic/nonlinear isotropic hardening constitutive model is proposed and derived to account for the Bauschinger effect existing in reverse plastic deformation. The new model is implemented into ABAQUS/Explicit v6.4 by a user subroutine VUMAT, which is verified by one-element numerical tests under tension, compression and reverse loading conditions. In addition, for the purpose of comparison, the Johnson-Cook isotropic hardening model is also applied for the materials. The Cockroft and Latham criterion is employed to predict surface fracture. / Although considerable discrepancies between the experimental and simulation results are observed, the proposed combined hardening model is more accurate in predicting material behavior in the reverse loading than the Johnson-Cook isotropic hardening model. In addition, the simulation results show that the proposed combined hardening material model has the potential to correctly predict the material behavior in the reverse loading process.