Issue 2, 2010 South African Journal of Industrial Engineering - Volume 21,
The quote above seems to accurately describe an industrial engineer - except that Prof NW Dougherty was a professor of Civil Engineering early in the 20th century. Nevertheless, the collection of articles included in the November 2010 edition of SAJIE clearly demonstrates the ability of industrial engineers to solve problems as described in the quote.
The visibility of engineering research in South Africa, 1975-2005 : feature article
South African Journal of Industrial Engineering 21, pp 1 –12 (2010)
Engineering as a branch of science has a crucial role in the growth of the economy. The growth and development of engineering is therefore highly relevant. One way to understand this is to examine the characteristics of the scientific knowledge produced in the field of engineering. Drawing on the publications in engineering from the ISI Web of Science over the last three decades, this paper looks at the visibility and importance of engineering research in South Africa. The visibility of research publications is studied in terms of the number of citations a publication receives. The analysis shows that the visibility of South African engineering research is determined by the number of authors involved in the production of a paper, the presence of international collaboration, the degree of collaboration, and the journals in which the papers are published. Engineering research in South Africa, compared with that of all subjects, is clearly growing. But the visibility of South African engineering publications, in comparison with all other subjects, has been diminishing in recent years.
Applying mixed integer programming for green supply chain management : general article
S. Sribenjachot and
South African Journal of Industrial Engineering 21, pp 13 –24 (2010)
This paper aims to guide those in supply chain management who make decisions on selecting factories, transportation modes, and the number of products to be manufactured. Solutions can be found through development of an optimisation model, using mixed-integer programming. Because green supply chain issues have become important, and new legislation has to be taken into account, carbon emissions costs must be included in the total costs of the supply chain, as in the optimisation model presented, which then has the ability to minimise total costs and to provide solutions that are both cost-effective and environmentally friendly.
Die doel van hierdie artikel is om leiding te verskaf aan diegene in voorsieningskettingbestuur wat besluite neem aangaande die keuse van fabrieke, vervoermetodes en die aantal produkte om te vervaardig. Oplossings kan gevind word by wyse van &apos;n optimiseringsmodel wat gemengde-heeltalprogrammering gebruik. Aangesien "groen" of te wel omgewingsvriendelike aspekte belangrik geword het en nuwe wetgewing in ag geneem moet word, moet die koste van koolstofemissies in die totale koste van die voorsieningsketting in berekening gebring word, soos wat in die optimiseringsmodel wat voorgehou word inderdaad gebeur. Sodoende kan &apos;n oplossing gevind word wat nie alleen koste-effektief is nie, maar ook omgewingsvriendelik.
Investigating of eco- and energy-efficient lubrication strategies for the drilling of light metal alloys : general article
G.A. Oosthuizen and
South African Journal of Industrial Engineering 21, pp 25 –38 (2010)
Energiebenutting maak een van die hoofdryfvere uit om eko-doeltreffendheid te behaal in boorprosesse in die motornywerheid. Nywerheidsbewustheid van die omgewingsimpak van gebruikte sny-vloeistowwe, en die negatiewe effek daarvan op werkergesondheid, het skerp toegeneem. Hierdie bewustheid het aanleiding gegee tot die ontwikkeling van smeringsmetodes soos deur-spil minimale hoeveelheid smering (Engels: Minimal Quantity Lubrication, MQL) vir die boor van aluminium-silikon legerings. In hierdie werk word die prestasie van MQL ondersoek teen verskillende snyspoed- en voertempo-kondisies deur middel van infra-rooi temperatuurmeting. Die resultate dui daarop dat MQL &apos;n lewensvatbare eko-vriendelike alternatief tot konvensionele vloedverkoeling is, wanneer aluminium-silikon legerings geboor word.
The scope of genetic algorithms in dealing with facility layout problems : general article
A. Kundu and
South African Journal of Industrial Engineering 21, pp 39 –49 (2010)
The paper presents a state-of-the-art review of the application of the Genetic Algorithm (GA), an important methodology in facility layout problems that can be used to gauge current and emerging trends in new design objectives and methodologies that address combinatorial optimisation aspects. The new developments in layout research analysed in this study provide a perspective on what the future of the field of study will be like. A tendency to use meta-heuristics like GA, which lean toward multi-objective approaches to layout and material handling system design, is observed.
Hierdie artikel bied &apos;n hedendaagse oorsig oor die aanwending van die Genetiese Algoritme (GA). DIt is &apos;n belangrike metodologie vir fasiliteitsuitlegprobleme wat gebruik kan word om die huidige en ontluikende tendense te bepaal in nuwe ontwerpdoelwitte- en metodologieë wat kombinatoriese optimisasie aspekte aanspreek. Die nuwe ontwikkelinge in uitlegnavorsing wat in hierdie artikel ondersoek word, verskaf &apos;n perspektief op die toekoms van die studieveld. &apos;n Tendens wat waargeneem word, is om meta-heuristiek soos GA aan te wend wat neig tot multi-doelwit-benaderings vir uitleg- en materiaalhanteringsontwerp.
A location-inventory model that includes delivery delay cost and capacity constraints in a stochastic distribution network : general article
South African Journal of Industrial Engineering 21, pp 51 –61 (2010)
In this paper, we present a distribution network design problem in a supply chain system that minimises the total cost of location, inventory, and delivery delay. Customers&apos; demands are random, and multiple capacity levels are available for the distribution centers. The problem is first formulated as a mixed integer convex programming model to optimally solve medium-sized instances, and then a heuristic is developed for solving large-sized instances.
In hierdie artikel word &apos;n distribusienetwerkprobleem in &apos;n voorsieningsketting voorgehou waar die totale koste van die ligging, voorraad en afleweringsvertragings geminimiseer word. Die vraag is lukraak en verskeie kapasiteitsvlakke is beskikbaar in die verspreidingsentra. Die problem word eers geformuleer as &apos;n gemengde-heeltal-konvekse model sodat mediumgrootte gevalle geoptimiseer kan word, waarna &apos;n heuristieke benadering ontwikkel word vir die oplos van grootskaalse aktiwiteite.
Managing risk for success in a South African engineering and construction project environment : general article
S. Chihuri and
South African Journal of Industrial Engineering 21, pp 63 –77 (2010)
The role that project risk management plays in ensuring the successful delivery of engineering and construction projects in South Africa is addressed in this paper. A survey questionnaire was developed to establish approaches used for risk management, and tools and techniques for risk identification. The findings revealed that project risk management had a significant role to play in the success of projects in South Africa. Respondents whose organisations practised structured risk management processes reported success in their projects. The main challenge was found to be in the implementation of risk management tools and techniques. Thus it became apparent that widespread adoption of project risk management in South Africa seemed to be impeded by a low knowledge and skills base, especially in terms of its application.
Die rol wat projekrisikobestuur in die suksesvolle aflewering van ingenieurs- en konstruksieprojekte in Suid-Afrika speel word hier aangespreek. &apos;n Vraelys is ontwikkel om benaderings tot risikobestuur asook toerusting en tegnieke vir risikoidentifisering te ondersoek. Die belangrikste bevinding is dat risikobestuur &apos;n belangrike rol speel in die sukses van projekte in Suid-Afrika. Die implementering van risikobestuurtoerusting en - tegnieke is aangedui as een van die grootste uitdagings wat oorkom moet word. Dit blyk dat die algemene aanvaarding van projekrisikobestuur in die Suid-Afrikaanse konteks bemoeilik word deur lae vlakke van kennis en vaardigheid.
The role of relationship management in the successful outsourcing of maintenance : general article
A.J. Van Niekerk and
South African Journal of Industrial Engineering 21, pp 79 –90 (2010)
Outsourcing some maintenance functions (or the entire maintenance of specific equipment) is one of the options available to maintenance managers in managing their department more effectively. Several factors should be considered in establishing an outsourced maintenance relationship with the potential for long-term success. This paper discusses the results of an investigation into the role of relationship management in the success of maintenance outsourcing by users of production facilities. The results of a survey in the process industry reveal a strong correlation between successful outsourced maintenance and proper on-going management of the outsourcing relationship, and indicate that shortcomings in the management of the relationship are a prime driver of failed maintenance outsourcing.
Die uitkontraktering van sommige instandhoudingstake (of die totale instandhouding van spesifieke toerusting) is een van die opsies wat die instandhoudingsbestuurder kan oorweeg om &apos;n afdeling meer effektief te bestuur. Verskeie faktore moet in ag geneem word in die vasstelling van &apos;n uitkontrakteringsverhouding met die potensiaal vir langtermyn sukses. Hierdie artikel bespreek die resultate van &apos;n ondersoek na die rol van verhoudingsbestuur in die sukses van uitkontraktering van instandhouding deur gebruikers van produksiefasiliteite. Resultate van &apos;n steekproef in die prosesnywerheid toon &apos;n sterk korrelasie tussen suksesvolle uitkontraktering en kontinue bestuur van die uitkontrakteringsverhouding. Tekortkominge in die bestuur van die verhouding is dikwels die primêre oorsaak van mislukte uitkontraktering in instandhouding.
Pareto optimal solutions for multi-objective generalized assignment problem : general article
M.K. Sharma and
South African Journal of Industrial Engineering 21, pp 91 –100 (2010)
The Multi-Objective Generalized Assignment Problem (MGAP) with two objectives, where one objective is linear and the other one is non-linear, has been considered, with the constraints that a job is assigned to only one worker - though he may be assigned more than one job, depending upon the time available to him. An algorithm is proposed to find the set of Pareto optimal solutions of the problem, determining assignments of jobs to workers with two objectives without setting priorities for them. The two objectives are to minimise the total cost of the assignment and to reduce the time taken to complete all the jobs.
&apos;n Multi-doelwit veralgemeende toekenningsprobleem ("multi-objective generalised assignment problem - MGAP") met twee doelwitte, waar die een lineêr en die ander nie-lineêr is nie, word bestudeer, met die randvoorwaarde dat &apos;n taak slegs toegedeel word aan een werker - alhoewel meer as een taak aan hom toegedeel kan word sou die tyd beskikbaar wees. &apos;n Algoritme word voorgestel om die stel Pareto-optimale oplossings te vind wat die taaktoedelings aan werkers onderhewig aan die twee doelwitte doen sonder dat prioriteite toegeken word. Die twee doelwitte is om die totale koste van die opdrag te minimiseer en om die tyd te verminder om al die take te voltooi.
New heuristics for minimising total completion time and the number of tardy jobs criteria on a single machine with release time : general article
South African Journal of Industrial Engineering 21, pp 101 –113 (2010)
This paper considers the bi-criteria scheduling problem of simultaneously minimising the total completion time and the number of tardy jobs with release dates on a single machine. Since the problem had been classified as NP-Hard, two heuristics (HR9 and HR10) were proposed for solving this problem. Performance evaluations of the proposed heuristics and selected solution methods (HR7 and BB) from the literature were carried out on 1,100 randomly generated problems ranging from 3 to 500 jobs. Experiment results show that HR7 outperformed HR10 when the number of jobs (n) is less than 30, while HR10 outperformed HR7 for n≥ 30.
Demand categorisation, forecasting, and inventory control for intermittent demand items : general article
J.M. Albarracin and
South African Journal of Industrial Engineering 21, pp 115 –130 (2010)
It is commonly assumed that intermittent demand appears randomly, with many periods without demand; but that when it does appear, it tends to be higher than unit size. Basic and well-known forecasting techniques and stock policies perform very poorly with intermittent demand, making new approaches necessary. To select the appropriate inventory management policy, it is important to understand the demand pattern for the items, especially when demand is intermittent. The use of a forecasting method designed for an intermittent demand pattern, such as Croston&apos;s method, is required instead of a simpler and more common approach such as exponential smoothing. The starting point is to establish taxonomic rules to select efficiently the most appropriate forecasting and stock control policy to cope with thousands of items found in real environments. This paper contributes to the state of the art in: (i) categorisation of the demand pattern; (ii) methods to forecast intermittent demand; and (iii) stock control methods for items with intermittent demand patterns. The paper first presents a structured literature review to introduce managers to the theoretical research about how to deal with intermittent demand items in both forecasting and stock control methods, and then it points out some research gaps for future development for the three topics.
Daar word algemeen aanvaar dat intermitterende vraag op toevalswyse voorkom, met verskeie periodes waar daar geen vraag is nie. Wanneer die vraag dan wel materialiseer, oorskry dit dikwels die eenheidsgrootte. Die bekende vooruitskattingstegnieke en voorraadbeleidstellings het min sukses waar intermitterende vraag voorkom, sodat nuwe benaderings nodig is om die problem aan te spreek. Om &apos;n geskikte voorraadbestuur-beleid te selekteer, is dit noodsaaklik om die vraagpatroon van die items te verstaan, juis in gevalle van intermitterende patrone. Die gebruik van &apos;n vooruitskattingstegniek soos dié van Croston, eerder as die makliker en meer algemene benadering van eksponensiële effening, word aanbeveel. Die vertrekpunt is om taksonomiese reëls vas te stel om die mees gepaste vooruitskattingstegniek en voorraadbeheerbeleid te selekteer sodat die duisende items wat in werklike omgewings aangetref word, hanteer kan word. Hierdie artikel dra by in soverre as dat 1) vraagpatrone gekategoriseer word; ii) metodes vir vooruitskatting van intermitterende vraagpatrone voorgehou word; en iii) voorraadbeheermetodes voorgestel word vir items met wisselende vraag.
A hybrid genetic algorithm-neural network approach for pricing cores and remanufactured cores : general article
M. Seidi and
South African Journal of Industrial Engineering 21, pp 131 –148 (2010)
Sustainability has become a major issue in most economies, causing many leading companies to focus on product recovery and reverse logistics. Remanufacturing is an industrial process that makes used products reusable. One of the important aspects in both reverse logistics and remanufacturing is the pricing of returned and remanufactured products (called cores). In this paper, we focus on pricing the cores and remanufactured cores. First we present a mathematical model for this purpose. Since this model does not satisfy our requirements, we propose a simulation optimisation approach. This approach consists of a hybrid genetic algorithm based on a neural network employed as the fitness function. We use automata learning theory to obtain the learning rate required for training the neural network. Numerical results demonstrate that the optimal value of the acquisition price of cores and price of remanufactured cores is obtained by this approach.
Volhoubaarheid het &apos;n belangrike saak geword in die meeste ekonomieë, wat verskeie maatskappye genoop het om produkherwinning en omgekeerde logistiek te onder oë te neem. Hervervaardiging is &apos;n industriële proses wat gebruikte produkte weer bruikbaar maak. Een van die belangrike aspekte in beide omgekeerde logistiek en hervervaardiging is die prysbepaling van herwinne en hervervaardigde produkte. Hierdie artikel fokus op die prysbepalingsaspekte by wyse van &apos;n wiskundige model.
Quantifying suppliers&apos; product quality : an exploratory product audit method : general article
S. Avakh Darestani,
N. Ismail and
South African Journal of Industrial Engineering 21, pp 149 –159 (2010)
The quality of the raw material and supplied product from suppliers plays a critical role in the quality of the final product. It has become the norm that vehicle manufacturers require their suppliers to measure product quality and service with a product audit method. Measuring quality of product is emphasised by QS9000 VDA6.5 and ISO / TS16949. From a competitive standpoint, and also to see continuous improvement in business, companies need to monitor their suppliers&apos; performance. Quality and delivery are two very important indicators of supplier performance. This paper presents a statistical method for measuring the quality of supplied product. This method allocates different weights to variables and attributes characteristics. Moreover, following normal distribution, the tolerance zone is divided to three regions with different scores. Therefore, the quality of suppliers&apos; products can be monitored based on the Product Quality Audit Score (PQAS). However, this method may be employed for organisations to monitor their raw material, work-in-process parts, and final product. It can be an indicator to monitor supplier quality behaviour.
Die gehalte van grondstowwe en produkte / komponente wat deur leweransiers verskaf word, speel &apos;n kritiese rol in die gehalte van die finale produk. Dit het die norm geword in die motorvervaardigingsbedryf dat daar van leweransiers verwag word om hulle produkkwaliteit en -diens te meet by wyse van &apos;n produkouditmetode. Die meting van produkkwaliteit word benadruk deur QS9000 VDA6.5 en ISO/TS16949. Uit &apos;n mededingingshoek en ook om kontinue verbetering te monitor, is dit noodsaaklik dat leweransiers se verrigting gemeet word. Gehalte en aflewering is twee van die belangrikste indikatore van leweransiersverrigting. In hierdie artikel word &apos;n statistiese model voorgehou vir die meting van die kwaliteit van die gelewerde produk. Die metode ken verskillende gewigte toe aan die veranderlikes en attribute. Daarbenewens, volgens die normaalverdeling, word die toleransiesone verdeel in drie areas met verskillende tellings. Gevolglik kan die kwaliteit van die leweransiers se produkte gemonitor word aan die hand van die produkgehalte-oudittelling ("product quality audit score - PQAS").
Activity-based costing for vehicle routing problems : general article
K. Koen and
J. v.d. Westhuizen
South African Journal of Industrial Engineering 21, pp 161 –171 (2010)
Activity-based costing (ABC) is a costing model that identifies activity costs in an organisation. It assigns the cost of activity resources to generate the actual cost of products in order to eliminate unprofitable products and to lower the prices of overpriced ones. The vehicle routing problem (VRP) is a combinatorial optimisation and nonlinear programming problem that seeks to service a number of customers with a fleet of vehicles in a cost-effective manner. In this article we propose a new approach to determine costing for vehicle routing type problems. The methodology incorporates the predictive sharing of a resource by clustering producers.
&apos;Activity-based costing&apos; (ABC) is &apos;n kostemodel wat die aktiwiteitskoste in &apos;n organisasie identifiseer. Dit allokeer die koste van die bronne sodat die ware koste van die vervaardiging en dienste van die produk bereken kan word om winsgewendheid te bepaal. Die &apos;vehicle routing problem&apos; (VRP) is &apos;n kombinatoriese optimisering en nie-lineêre programmeringsprobleem wat verskeie kliënte met &apos;n vloot voertuie in die mees koste- effektiewe manier bedien. Die artikel bespreek &apos;n nuwe metode om die kombinasie van probleme op te los. Die metode maak gebruik van groeperingsalgoritmes om meer akkurate voertuig deling te voorspel.
Reconfigurable product routing and control for mass customisation manufacturing : general article
A.J. Walker and
South African Journal of Industrial Engineering 21, pp 173 –189 (2010)
Reconfigurable control of flexible manufacturing systems can allow for the efficient and responsive production of customised product instances. This can aid in providing make-to-order business models for various small- to medium-sized enterprises in South Africa, and provide competitive advantage in a dynamic global marketplace. Reconfigurable control application requires an understanding of the modes of production variability in mass customisation manufacturing. Temporally uncorrelated workflow routings are considered as one of these production variability modes. In this light, this paper addresses the flexible material payload routing problem, and presents a mobile robot platform that has been developed to research and design reconfigurable routing systems.
Verstelbare beheer van aanpasbare vervaardigingstelsels kan die doeltreffende en reaktiewe produksie van doelgemaakte produkeksemplare toelaat. Hierdie beheer kan assisteer in die voorsiening van vervaardig-na-bestellingbesigheidsmodelle aan &apos;n aantal klein- tot medium-grootte ondernemings in Suid-Afrika, en aan hulle &apos;n kompeterende voorsprong bied in &apos;n dinamiese globale mark. Die instelling van verstelbare beheer vereis dat die modi van produkveranderlikheid in massa verbruikersaanpassingsvervaardiging verstaan word. Hierdie artikel spreek die probleem van aanpasbare roetebepaling van materiaalvragte in massa verbruikersaanpassingsvervaardiging aan. &apos;n Mobiele robotplatform, ontwikkel vir navorsing in verstelbare roetebepalingstelsels, word ook voorgelê.
Determining tactical operational planning policies for an auto carrier - a case study : general article
South African Journal of Industrial Engineering 21, pp 191 –205 (2010)
This study was done to assist a local auto carrier company with tactical operational planning. The objective of the planning process is to maximise the number of vehicles delivered while being on time and adhering to staff and maintenance schedule constraints. We investigated the feasibility of allowing part of the fleet to roam the closed spatial network, as opposed to the traditional assignment of the complete fleet to fixed routes. We developed decision-making rules for roaming and fixed-to-route auto carriers, and evaluated the quality of these proposed rules, in combination with different fleet compositions, using discrete event simulation and four performance measures.
We found that the auto carrier company should adopt a tactical operations policy where at least 50% of the fleet is allowed to roam, while roaming auto carriers pick vehicles to transport according to specific rules.
Hierdie studie is gedoen om &apos;n plaaslike motorvervoer-onderneming te help met taktiese bedryfsbeplanning. Die doelwit van die beplanningsproses is om die aantal voertuie wat betyds afgelewer word te maksimeer met inagneming van personeel- en instandhoudingbeperkings. Ons het die moontlikheid dat &apos;n deel van die vragmotorvloot swerwend in die geslote ruimtelike roete-network moet opereer, ondersoek. Dit is in teenstelling met die tradisionele vaste toedeling van vragmotors aan roetes. Besluitnemingreëls vir swerwende en vaste-roete vragmotors is ontwikkel, en die gehalte van die reëls is met diskrete simulasie en vier prestasiemaatstawwe evalueer. Ons het bevind dat die vervoeronderneming &apos;n bedryfsbeleid behoort te aanvaar wat toelaat dat ten minste 50% van die vloot swerf, terwyl hierdie swerwende vragmotors voertuie volgens spesifieke reëls by oplaaipunte moet kies.
How to control process variability more effectively : the case of a B-complex vitamin production process : general article
M.A. Djauhari and
South African Journal of Industrial Engineering 21, pp 207 –215 (2010)
This paper presents a new procedure for controlling process variability where (i) the quality of the process is determined by more than one quality characteristic, and (ii) the correlations among those quality characteristics must be taken into consideration. The ability of this procedure to detect an abrupt shift of covariance structure is an improvement on the standard practice based on generalised variance. An experience of the production process of the B-complex vitamin is reported to illustrate the merit of the proposed procedure.
Die metodes van &apos;n nuttige gehaltebeheerprosedure vir die bepaling van gehaltebeheerverlies wat &apos;n chemiese produk met meervoudige gehalte-eienskappe besit, word beskryf teen die agtergrond van kovariasie. Die prosedure word getoets in die praktyk by die vervaardiging van &apos;n gegewe chemiese produktipe. Aspekte van voordele en nadele van die metode word ook gewetensgetrou behandel.
Effect of cereal binder, moisture, and clay contents on the functional properties of clay-bonded core and moulding sands : general article
S.G. Aiyeru and
South African Journal of Industrial Engineering 21, pp 217 –230 (2010)
The effects of alikama cereal and clay binder additions and moisture contents on the functional properties of clay-bonded core and moulding sands are explored. The outcomes suggest that improved functional properties resulting from the effective bonding properties of the cereal and clay binders were obtained when a certain optimum level of each of the additives was used with the optimum percentage of cereal binder and tempering water. This work establishes the viability of the cereal binder addition in a clay bonded core and moulding sand mixes for industrial and laboratory applications.
Die uitwerking van byvoegings van graan- en kleibinders en voginhoud by gietvormklei vir gebruik by gietprosesse word ondersoek. Die resultate dui op verbeterde funksionele eienskappe wat voortspruit uit optimum benutting van bestanddele.