Dosimetrie van Heelliggaamsbestraling met Elektrone vir die Behandeling van Mycosis Fungoides

A six-field method for whole-body radiation with 3,4 MeV electrons obtained from a Mevatron 8 linear accelerator, is described. The physical properties of the electrons are given, and a method is described whereby the wholebody isodose distributions can be predicted during wholebody irradiation

What determines product ramp-up performance? : a review of characteristics based on a case study at Nokia Mobile Phones

We present a conceptual model to explore the essential characteristics that affect product ramp-up performance in the consumer electronics industry, specifically in the mobile phones sector. Our findings are based on data analysis within Nokia’s mobile phones business group. Fast product ramp-ups are particularly critical for companies in which short product lifecycles prevail and in which development teams are required to work on new development projects than spending time with ramp-up support. Our model analyzes, extends and structures the results from other studies into five main characteristics: the product architecture, the product development process, the logistics system, the manufacturing capability and the external environment. We discuss the factors that describe and represent these five main characteristics on a quantitative basis and assess the impact of these characteristics on ramp-up performance with different measures in the model

Lead time anticipation in supply chain operations planning

Linear programming (LP) models for Supply Chain Operations Planning are widely used in Advanced Planning Systems. The solution to the LP model is a proposal for order releases to the various production units (PU) in the supply network. There is a non-linear relationship between the work-in-process in the PU and the lead time that is difficult to capture in the LP model formulation. We propose a two-step lead time anticipation (LTA) procedure where the LP model is first solved irrespective of the available production capacity and is subsequently updated with aggregate order release targets. The order release targets are generated by a local smoothing algorithm that accounts for the evolution of the stochastic workload in the PU. A solution that is both feasible with respect to the planned lead time and meets the material requirements may not exist. By means of discrete event simulation, we compare a conservative strategy where the production quantities are reduced to an optimistic strategy where the planned lead time constraint is allowed to be violated

Die wese van godsdienssin - ’n empiriese studie

In this article the following issues concerning the essence of religiosity are considered: faith, trust, decision making, knowledge of principles, commitment, direction, hope, peace, meaning and security. The respondents used in this study were politicians, businessmen and teacher educators from all sectors and regions of South Africa. Higher order factor analysis and item analysis were used to evaluate the validity and reliability of the questionnaire. Subsequently differential differences were investigated by applying Hotelling's T-square test followed by the Student t-test as well as Multivariate Analysis of Variance (ANOVA) and Scheffe. Significant differences in the degree of religiosity were found between language and religious groups, as well as between respondents with different educational qualifications and between those living in urban and rural areas. Ministers of religion should note that it is essential to guide believers to a greater commitment and to the religious seeking of meaning and peace. The correct knowledge of and insight into the essence of religiosity will lead to attaining this goal

The PASS model for the assessment of cognitive functioning in South African schools: a first probe

Diversity is an acknowledged characteristic of the South African society. Traditional standardised methods of assessment for cognitive functioning have been discouraged or abandoned, as they have been found to be discriminatory. Arguing for a systematic assessment process, a previous researcher has stated that standardised methods are the best ways of achieving understanding of the reasons for the breakdown in learning and ensuring effective intervention. An alternative mod el of intelligence and cognitive functioning developed in previous work is explored for possible application within the South African context. This model, referred to as the PASS model, refers to the cognitive processes of Planning, Attention, Simultaneous and Successive processing. The exploration of the PASS model is extended to the assessment tool used to quantify these four cognitive processes. The assessment tool is called the Cognitive Assessment System (CAS). The question posed in the study was whether results obtained with this PASS model of intelligence could provide insight into the cognitive functioning of South African children. To establish the validity of the CAS (the assessment tool), the scores were correlated with related achievement scores obtained. The sources for achievement were obtained from the normed standardised Woodcock Diagnostic Reading Battery (WDRB) as well as the pupil's school year marks for the previous year. The data obtained from the CAS, Woodcock Diagnostic Reading Battery (WDRB), and the scholastic marks obtained from school subjects for December 2000 were therefore examined for correlations. The findings of this first probe indicated that the PASS model of intelligence correlates with reading and scholastic achievement in the South African context. The consequence of these findings impacts on the strategies employed for assessment of and intervention with reference to children having difficulties in learning within the South African context. The need for additional research to exp lore the diagnostic value of the CAS in the wider community is on e of the challenges emanating from this probe. (South African Journal of Education: 2003 22(3): 246-252

The impact of product complexity on ramp-up performance

Fast product ramp-ups are crucial in consumer electronics because short product lifecycles prevail and profit margins diminish rapidly over time. Yet many companies fail to meet their volume, cost and quality targets and the ramp-up phase remains largely unexplored in new product and supply chain management research. This study identifies the key product characteristics that affect ramp-up performance using operational data from the cell phone industry. We investigate three research questions: (1) How to measure software and hardware complexity characteristics of consumer electronics products – and specifically cell phones? (2) To what extent drive product complexity characteristics manufacturing performance? and (3), in turn, to what extent drive manufacturing performance and complexity characteristics ramp up performance? The findings contribute to operations management literature in three ways: First, our model reflects the growing importance of software characteristics in driving hardware complexity, an aspect that prior empirical ramp-up studies have not yet addressed. Second, specific hardware and software complexity characteristics (i.e., component count, parts coupling and SW code size) primarily drive the performance of the manufacturing system in terms of final yield and effective capacity. And finally, effective capacity together with the novelty aspects of both software and hardware complexity (i.e., SW novelty and product novelty) are the key determinants of ramp-up performance

How does development lead time affect performance over the ramp-up lifecycle? : evidence from the consumer electronics industry

In the fast-paced world of consumer electronics, short development lead times and efficient product ramp-ups are invaluable. The sooner and faster a firm can ramp-up production of a new product, the faster it can start to earn revenues, profit from early market opportunities, establish technology standards and release scarce development resources to support new product development projects. Yet, many companies fail to meet their time-to-market and time-to-volume targets and the complex interrelationships between product characteristics, development lead time and ramp-up performance are largely unexplored. In response to these limitations our study focuses on three research questions: (1) To what extent is ramp-up performance determined by development lead time and product complexity? (2) How do these relationships change in the course of the ramp-up lifecycle? and (3) How can the results be explained? Our results contribute to the field of operations management in three ways. First, we offer a more comprehensive and enriched analysis of the drivers for development lead time and ramp-up performance in the cell phone industry. Second, we demonstrate that late schedule slips – although disastrous for customer relations in which due dates are crucial – provide the opportunity to build up (semi-finished) product buffers which in turn increase the initial ramp-up performance. Third, we show that it is important to take these effects into account in a jointly and lifecycle-dependent manner. Thus, our insights support management efforts to anticipate the consequences of product design decisions, predict development schedule risk levels, and make informed decisions about production volume commitments