A model to optimize payloads at PFG Building Glass

Brits, R.; Conradie, P.J.

Abstract: While improving customer service by allowing user definable mixed load orders of their plate glass product, PFG Building Glass was confronted with a problem of calculating the feasibility and optimum load layout for transporting the glass, without transgressing the regulatory requirements. In this article the development of an integrated solution is discussed, including the definition of a mathematical model that calculates the axle weights, the optimization model based on linear programming, as well as the user interface for their current information system. The solution enables the company to proceed with e-commerce service to clients, since the system can evaluate the transport feasibility and give real time feedback to clients.

Die uitbreiding van kliëntediens by PFG Building Glass om bestellings van gemengde glasplaatprodukte per vrag te aanvaar, het die onderneming voor 'n uitdaging geplaas om te bereken of sulke bestellings binne die wetlike regulasie vervoer sal kan word. Hierdie artikel bespreek die ontwikkeling van 'n geïntegreerde oplossing wat bestaan uit 'n wiskundige model wat die gewig per as bereken, 'n optimiseringsmodel wat die vraguitleg bepaal en op liniêre programmeringsbeginsels gebaseer is, sowel as die gebruikersintervlak met die onderneming se bestaande inligtingstelsel. Hierdie ontwikkeling stel die onderneming instaat om 'n e-besigheidsdiens vir kliente daar te stel, aangesien terugvoer oor die uitvoerbaarheid van 'n bestelling uit 'n vervoeroogpunt intyds aan die kliënt gekommunikeer kan word.

 

 

A two-product inventory system with product interaction

Yadavalli, V.S.S; .Hargreaves, C.

Abstract: In this paper, we study a two-component continuous review inventory system. We assume that demand occurs according to a Poisson process and that a demand can be satisfied only if both the components are available in the inventory. Back-orders are not permitted. We assume that the lead-time distribution of one product is arbitrary and the other is exponential. Identifying the underlying process as a semi-regeneration process we find the stationary distribution of the inventory level, the performance measures such as mean stationary rate of number of lost demands, the demands and the reorders made. A numerical example illustrates the results.

Die artikel ondersoek 'n tweekomponent- deurlopende oorsigvoorraadstelsel. Daar word aanvaar dat aanvraag 'n Poissonproses is en dat aanvraag slegs bevredig kan word indien beide die komponente in die voorraad beskikbaar is. Agterstallige bestellings word nie toegelaat nie. Daar word aanvaar dat die lewertydverdeling van die een produk arbitrêr en die ander eksponensieël is. Indien die onderliggende proses as 'n semigenerasieproses geïdentifiseer word, kan die stasionêre verspreiding van die voorraadvlak bepaal word. Maatstawwe van vertoning soos mediaan-stasionêre koers van die hoeveelheid verlore aanvraag, die aanvraag en herbestellings wat gedoen is word bepaal. 'n Numeriese voorbeeld illustreer die resultate.

 

 

Control charts for stationary vector arma processes

Yadavalli, V.S.S.; Claasen, S.J.

Abstract: In practice, there are many quality control situations where a product under consideration may have two or more interrelated quality characteristics and observations of each characteristic are serially correlated. One of the objectives of management is to investigate whether or not all these characteristics of the product simultaneously satisfy the required specifications. To the author's best knowledge, no concrete attempts have been made so far to construct the control charts for such situations, particularly when the data arise from vector autoregressive-moving average (VARMA) processes. It is this problem that has been addressed in this paper. A few methods are suggested for constructing the control charts. When assumptions about independence and normality break down, a bootstrap method, perhaps for the first time, is suggested to attack the problem. Some illustrative examples are discussed.

In die praktyk is daar vele kwaliteitbeheersituasies waar 'n betrokke produk een of twee onderling verbonde kenmerke kan hê en waarnemings van elke kenmerk serie gekorreleer is. Een van die doelwitte van bestuur is om te ondersoek of hierdie kenmerke van die produk gelyktydig aan die vereiste spesifikasies voldoen al dan nie. Na die outeur se beste wete, is daar tot dusver geen daadwerklike pogings aangewend om die beheergrafieke vir sodanige situasies op te stel nie, veral waar die data ontstaan uit vektor outoregressief bewegende gemiddelde (VARMA) prosesse. Hierdie probleem geniet in hierdie artikel aandag. 'n Aantal metodes vir die opstel van die beheergrafieke word voorgestel. Wanneer aannames oor selfstandigheid en normaliteit faal, word 'n skoenlusmetode voorgestel om die probleem die hoof te bied. 'n Aantal voorbeelde ter toeligting word bespreek.

 

 

The art of simulation modelling

Kruger, P.S.

Abstract: It is the contention of the author that practising the "art" of modelling has been, and always will be, of great importance to the ultimate success of any project employing a simulation approach. Yet very few publications address this aspect of simulation modelling exclusively. This paper is an attempt to focus attention on some of these "softer" issues of simulation modelling. By using the concept of a Simulation Syndrome the paper endeavours to highlight some of these issues and to serve as a reminder to simulation modellers of some aspects of the "art" of modelling that are often taken for granted.

"Advice is seldom welcome; and those who want it the most always like it the least" Lord Chesterfield

Die outeur is van mening dat die "kuns" van modellering van groot belang is vir die uiteindelike sukses van enige projek waar gebruik gemaak word van 'n simulasiebenadering. Nietemin bestaan daar weinig publikasies waar hierdie aspek van simulasiemodellering spesifiek aangespreek word. Hierdie artikel is 'n poging om die aandag te vestig op sommige van die "sagter" aspekte van simulasiemodellering en die doelwit word bereik deur gebruik te maak van die konsep van 'n Simulasie-Sindroom. Op hierdie wyse word die gebruikers van simulasiemodellering herinner aan somminge aspekte van die "kuns" van modellering wat dikwels as vanselfsprekend aanvaar word.

 

 

IS environmental alignment and business performance: a conceptual approach

Garg, K.; Joubert, R.J.O.; Pellissier, R.

Abstract: This paper proposes a conceptual model termed "IS environmental alignment" that focuses on the support provided by IS strategy to minimize the gap between perceived environmental uncertainty and realized / objective environmental conditions. The model uses the Chan et al alignment measurement method to measure IS strategic alignment as it provides a quantitative measure. In due course the proposed model would be tested in industry and would examine the affect of IS environmental alignment on business performance. The implication of the model lies in the effective use of deployed IS systems by organizations.

'n Konsepmodel word voorgelê wat handel oor "IS-omgewingsaanpassing". IS-strategie-ondersteuning by die minimisering van die gaping tussen waargenome omgewingsonsekerheid en gerealiseerde / objektiewe omgewingstoestande. Die model maak gebruik van die Chan et al aanpassingsmeetmetode om IS-strategie-aanpassing op 'n kwantitatiewe basis te bepaal. Met die verloop van tyd sal die konsepmodel in die praktyk getoets word om te toon hoe IS-strategie-aanpassing sakevertoning affekteer. Die effektiewe ontplooiing van IS-stelsels by ondernemings word voorgehou.

 

 

An environmental comparison of plastic and paper consumer carrier bags in South Africa: implications for the local manufacturing industry

Sevitz, J.; Brent, A.C.; Fourie, A.B.

Abstract: The conventional consumer carrier bags have recently received considerable attention in South Africa. The choice of material for these bags, based on environmental preferences in the South African context, could significantly influence the local manufacturing industry. Life Cycle Assessment (LCA), an environmental management tool, has been applied to objectively evaluate and compare the overall environmental impacts of the complete life cycles (from raw material extraction to final disposal) of consumer plastic and paper carrier bags in South Africa. Paper bags have a higher carrying capacity compared to plastic bags and different use ratios were subsequently evaluated. Plastic bags have a lower environmental impact for use ratios of up to 2.5 plastic bags to one paper bag. Above this ratio the conclusions are not reliable. Paper bags would need to increase its recycled content significantly to be competitive in terms of environmental impacts. The re-use of thicker plastic, as proposed by the new plastic bag legislation, has the potential to significantly lower the impact of plastic bags.

Die konvensionele gebruikersdrasakke het onlangs aansienlike aandag in Suid-Afrika ontvang. Die keuse van materiaal vir hierdie sakke, wat gebaseer is op omgewingsvoorkeure in die Suid-Afrikaanse konteks, kan 'n wesenlike invloed uitoefen op die plaaslike vervaardigingsindustrie. Lewenssiklusanalise (LCA), 'n omgewingsbestuurgereedskap, is aangewend vir 'n objektiewe evaluasie en vergelyking van die algehele omgewingsimpakte van die totale lewenssiklus (vanaf grondstofekstraksie tot finale wegdoening) van gebruikersplastiek- en papierdrasakke in Suid-Afrika. Aangesien papiersakke 'n hoër drakapasiteit het in vergelyking met plastieksakke, is verskillende gebruiksverhoudings evalueer. Plastieksakke het 'n laer omgewingsimpak vir gebruiksverhoudings tot en met 2.5 plastieksakke vir elke papiersak. Die gevolgtrekkings van die studie is nie betroubaar vir hoër verhoudings nie. Die persentasie hergesirkuleerde materiaal in papiersakke moet verhoog word om mededingend te wees in terme van omgewingsimpak. Die hergebruik van dikker plastiek, soos voorgestel deur die nuwe plastieksakwetgewing, het die potensiaal om die algehele impak van plastieksakke wesenlik te verlaag.-

 

 

The development of a performance measurement system for maintenance

Visser, J.K.; Pretorius, M.W.

Abstract: Business enterprises are under increasing pressure to become internationally competitive due to globalisation. World-class companies from abroad can now easily compete with local companies, introducing high quality products and services to the local community and industry. The pace of technological change is also forcing companies to increase productivity and to become more cost effective. Performance management is part of the strategic management process in the business enterprise and the maintenance department therefore has to address this as part of the strategy formulation for the maintenance function. This paper outlines the strategic management process that is required in the maintenance department and defines a systematic process to develop a performance measurement system for maintenance.

Besigheidsondernemings is onder toenemende druk om internasionaal kompeterend te word weens globalisering. Wêreldklas maatskappye kan nou maklik met plaaslike maatskappye meeding deur hoë kwaliteit produkte en dienste aan die plaaslike gemeenskap en nywerheid te lewer. Die tempo van tegnologiese verandering dwing maatskappye ook om produktiwiteit te verhoog en meer koste-effektief te word. Prestasiebestuur is deel van strategiese bestuur in 'n onderneming en die instandhoudingsafdeling moet derhalwe prestasiebestuur aanspreek as deel van die ontwikkeling van strategie vir die instandhoudingsfunksie. Hierdie artikel bespreek die strategiese bestuursproses soos benodig in die instandhoudingsafdeling en stel 'n sistematiese proses voor vir die ontwikkeling van 'n prestasiemetingstelsel vir instandhouding.

 

 

Investigation of an appropriate technology forecasting process for Sasol for the new energy era

Ma, L.; Buys, A. J.

Abstract: Sasol is predominantly an energy-based company. The energy industry is undergoing a fundamental transformation that may have a profound impact on Sasol's overall business. This study has been carried out to investigate the need to establish an appropriate technology forecasting process for the new energy era. Although there exist some evidence of technology forecasting within Sasol, they are scattered and unsophisticated. Technology forecasting as a tool enables managers to make better decisions and encourages networking and knowledge sharing within the organization, an important trait of a 'Learning Organization'. A theoretical framework of technology forecasting for Sasol is thereby formulated.

Sasol is hoofsaaklik 'n energie-gebaseerde maatskappy. Die energie-industrie ondergaan tans 'n diepgaande transformasie wat 'n wesenlike impak kan hê op Sasol se totale besigheid. Hierdie studie is uitgevoer om die behoefte vir 'n toepaslike tegnologie-vooruitskattingsproses vir die nuwe energie-era te bepaal. Alhoewel daar bewyse bestaan vir tegnologie-vooruitskatting binne Sasol, is dit verspreid en ongesofistikeerd. Tegnologie-vooruitskatting is 'n gereedskapstuk wat bestuurders in staat stel om beter besluite te neem en bevorder die gebruik van netwerke en kennis-uitruiling binne die organisasie, 'n belangrike eienskap van 'n 'Lerende Organisasie'. 'n Teoretiese raamwerk vir tegnologie-vooruitskatting vir Sasol word sodoende geformuleer.

 

 

The development and evaluation of an improved Cloverleaf model for the assessment of technology readiness for commercialisation

Oosthuizen, R.; Buys, A.J.

Abstract: Technology commercialisation is the process that converts technology that was developed for the government, e.g., defence technology, to commercial use, thereby benefiting the wider community. As technology commercialisation is a high risk and expensive process, care must be taken to commercialise only those technologies with the best chances for success. Heslop, McGregor & Grifith developed the Cloverleaf Model to assess technology readiness for commercialisation. This model is evaluated and improved for use in the South African environment.

Die kommersialisering van tegnologie is die proses waardeur tegnologie wat ontwikkel is vir die Staat, byvoorbeeld verdedigingstegnologie, omgeskakel word vir kommersiële gebruik tot voordeel van die breër gemeenskap. Aangesien tegnologie-kommersialisering 'n hoë-risiko en duur proses is, moet net daardie tegnologieë gekommersialiseer word wat die beste kanse vir sukses het. Heslop, McGregor & Grifith het die Cloverleaf Model vir die assessering van tegnologie-gereedheid vir kommersialisering ontwikkel. Hierdie model is ge-evalueer en verbeter vir gebruik in die Suid-Afrikaanse omgewing.

 

 

The development of a computer driven jigsaw

Lubbe, A.J.; Raath, H.

Abstract: With a jigsaw, sharp inside corners can only be sawn out if the blade of the jigsaw is lifted out of the material and the corner is approached from two different sides. For the blade to be able to re-enter the material no material must be present at the entry point. The most important feature of an automated jigsaw is that it should be able to round off inside corners on a contour and automatically return to these corners to remove material left between the round off and the contour. With this development project an automated jigsaw machine was designed, built and tested. Emphasis fell on the development of software that enables one to draw contours that need to be sawn out, change these contours into cutter paths for the jigsaw and transform the cutter paths into digital format necessary to control the jigsaw machine via the parallel port of a personal computer.

 

'n Figuursaag kan slegs skerp binnehoeke saag as die lem uit die materiaal uitgelig word en die hoek van twee kante af gesaag word. Waar die lem weer in die materiaal ingaan, mag geen materiaal aanwesig wees nie. Die belangrikste eienskap van 'n ge-outomatiseerde figuursaag is dat kontoere so gesaag moet word dat binnehoeke afgerond kan word en die materiaal tussen die afronding en die gewensde kontoer outomaties verwyder moet word. Met hierdie ontwikkelingsprojek, is 'n ge-outomatiseerde figuursaag ontwerp, gebou en getoets. Die klem van die projek val op die ontwikkeling van sagteware waarmee kontoere wat uitgesaag moet word, geteken kan word, omgeskakel kan word in 'n snyerpad vir die saaglem en gebruik kan word vir digitale beheer van die saagmasjien deur gebruik te maak van die parallelpoort van 'n persoonlike rekenaar.

 

 

Learning management systems: engineering the education industry to educate the industrial engineer

Van Dyk, L.

Abstract: A learning management system (LMS) is any infrastructure on which e-learning can be built and delivered. In this article two sides of the LMS coin are investigated: On the one side, it is argued that industrial and systems engineering skills are equally relevant for learning systems as for as for any other system. To support this argument, an analogy is drawn between the management of learning systems and the management of manufacturing systems. On the other side of the coin, the educational issues and concerns related to implementing an LMS at the University of Pretoria are investigated by means of a case study in the Industrial Engineering department. It is concluded that the industrial engineering educator is in the unique position of understanding and contributing towards the engineering of the education industry whilst educating the industrial engineer.

'n Leerbestuurstelsel (LMS) is enige infrastruktuur waarop e-leer gebou en afgelewer kan word. In hierdie artikel word beide kante van die LMS muntstuk ondersoek: Aan die een kant word getoon dat bedryfsingenieursvaardighede en -beginsels ewe toepaslik is op leerstelsels as op vervaardigingstelsels. Om hierdie argument te steun word 'n analogie getrek tussen die bestuur van leerstelsels en die bestuur van vervaardigingstelsels. Aan die ander kant van die muntstuk word die opvoedkundige aspekte verbonde aan die implementering van 'n leerbestuurstelsel (LMS) aan die Universiteit van Pretoria ondersoek aan die hand van 'n gevallestudie in die Bedryfsingenieursdepartment. Die gevolgtrekking word gemaak dat die bedryfsingenieurs-opleier in 'n unieke posisie is om die opleidingsindustrie te begryp en by dra tot the ontwikkeling daarvan terwyl die bedryfsingenieur opgelei word.