Scielo RSS <![CDATA[South African Journal of Industrial Engineering]]> http://www.scielo.org.za/rss.php?pid=2224-789020140003&lang=pt vol. 25 num. 3 lang. pt <![CDATA[SciELO Logo]]> http://www.scielo.org.za/img/en/fbpelogp.gif http://www.scielo.org.za <![CDATA[<b>Note from the editor</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S2224-78902014000300001&lng=pt&nrm=iso&tlng=pt <![CDATA[<b><i>Prof K</i></b> <b><i>Adendorff</i></b> <i>(21 April 1931 - 26 October 2014)</i>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S2224-78902014000300002&lng=pt&nrm=iso&tlng=pt <![CDATA[<b>Dynamic inventory models: An illustrative case study</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S2224-78902014000300003&lng=pt&nrm=iso&tlng=pt The study revisits the subject matter of inventory control, a continual part of the activities of wide-ranging organisations internationally. The mathematical model is presented of a particular situation that deals with the regular acquisition of a material required for a production process in a volatile environment of varying demand and fluctuating price. The usual process dynamics are demonstrated against a background of diverse choices of probability density function. The model makes use of Normal and Weibull distributions.<hr/>Die studie herbesoek die bakermat van voorraadbeheer om hernude klem te lê op die ontwikkeling van gepaste wiskundige modelle vir uiteenlopende voorraadsituasies wat tans internasionaal met welslae gebruik kan word. 'n Rudimentêre model word voorgehou wat desnieteenstaande eenvoud dog onmisbare gereedskap soos Dinamiese Programmering en keuse van kansdigtheidsfunksie voorhou vir stogastiese behandeling van die onbestendige gedrag met verloop van tyd van voorraadprys- en aanvraag. Die model gebruik Normaal- en Weibullverdelings. <![CDATA[<b>Evaluating the ability of decision-makers to estimate risks effectively in industrial applications</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S2224-78902014000300004&lng=pt&nrm=iso&tlng=pt There are many factors to be considered in risk management that influence the effective control of risk either beneficially or detrimentally. An improvement in the quality of risk analysis will enable risk managers and decision-makers to make more accurate decisions that would benefit all stakeholders. The aim of this research was to determine the effectiveness of the most commonly employed risk analysis methods. Two decision problems and two hypothetical risk analysis problems were presented to groups of respondents who were asked to choose a correct answer from the given options. The results showed no significant association between a person's age or experience and their choice or decision about risk management. The only association was found between a higher level of professional qualification and the correct choice, when a decision problem was given without providing a decision tree.<hr/>Verskeie faktore moet in ag geneem word in risikobestuur wat die effektiewe beheer van risikos voordelig of nadelig beïnvloed. 'n Verbetering in die kwaliteit van risiko analise kan risikobestuurders en besluitnemers help om meer akkurate besluite te neem tot voordeel van alle belanghebbers. Die doel van hierdie studie was om die effektiwiteit van die mees algemene risiko bepaling metodes te evalueer. Twee besluitnemingsprobleme en twee risiko-analise probleme is vir groepe respondente voorgehou, en respondente is versoek om 'n korrekte keuse te maak uit 'n lys moontlike oplossings. Die resultate toon dat ouderdom of ervaring nie 'n betekenisvolle invloed op 'n effektiewe besluit of keuse met betrekking tot risikobestuur het nie. 'n Betekenisvolle assosiasie is wel waargeneem tussen 'n hoër vlak van professionele kwalifikasie en die korrekte keuse, wanneer 'n besluitnemingsprobleem sonder dat 'n besluitboom verskaf is. <![CDATA[<b>Supply chain management: A framework of understanding</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S2224-78902014000300005&lng=pt&nrm=iso&tlng=pt The topic of supply chain management (SCM) is complex to understand because it encompasses many different flows of activities, components, functions, and role-players. The literature is scattered across multiple functions, varies in scope, and is often confined to certain elements within SCM. This article aims to provide a literature overview of SCM. It is explained with the aid of a newly-developed framework of understanding that offers a graphical representation of the term. It unifies and condenses different components within SCM and shows the relationship between them. The framework was developed by identifying the main themes in the definitions for SCM, examining existing categorisations and frameworks in SCM, and analysing frameworks in other disciplines. The outcome of this article can be used as a guide to explain and orientate researchers and practitioners in the field.<hr/>Die onderwerp van voorsieningskettingbestuur (VKB) is kompleks om te verstaan omdat dit baie verskillende komponente, vloei van aktiwiteite, funksies, en rolspelers insluit. Die literatuur oor VKB is versprei oor verskeie funksies, wissel in omvang, en word dikwels beperk tot sekere elemente binne VKB. Die doel van hierdie artikel is om 'n literatuur oorsig oor die onderwerp van VKB te voorsien. VKB word verduidelik met behulp van 'n nuut-ontwikkelde raamwerk van verstaan: 'n grafiese voorstelling van die term. Dit verenig die verskillende komponente binne VKB, en toon die verwantskap tussen hulle. Die raamwerk is ontwikkel deur die belangrikste temas in die definisies van VKB te bestudeer, en bestaande kategorisering en verwysingsmodelle te ontleed. Die uitkomste van die artikel kan gebruik word as 'n gids om navorsers en praktisyne te oriënteer in die veld. <![CDATA[<b>A multi-criteria decision-making approach that combines fuzzy topsis and DEA methodologies</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S2224-78902014000300006&lng=pt&nrm=iso&tlng=pt Employee selection is a multi-criteria decision-making (MCDM) problem for selecting suitable applicants from a ready pool. The selection aims to make use of their knowledge, relevant skills, and other characteristics to perform a specific job. The aim of this study is to develop a systematic approach for selecting the best candidates among the air traffic controllers (ATCs) for aviation in Saudi Arabia. Three integrated methods were employed for decision-making in this study. First, a fuzzy decision tree was applied to determine the criteria weights, then the fuzzy Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) was employed to rank the attributes. In the last step, the Data Envelopment Analysis (DEA) was used to transform the qualitative variables into quantitative equivalences. A survey was conducted by national and international decision-makers to elicit the necessary information on the criteria and sub-criteria of the air traffic control system. The decision problem was formulated by employing five criteria and ten applicants. The relationship between the fuzzy TOPSIS and fuzzy-weighted average was very positive for decision-making. The outcomes of the fuzzy TOPSIS and DEA encouraged the development of a decision support system for the selection of ATCs.<hr/>Die kies van werknemers vanuit 'n lys van gepaste aansoeke is 'n multi-kriteria besluitnemingsprobleem. Die seleksie se doel is om gebruik te maak van die potensiële werknemers se relevante vaardighede en ander eienskappe om 'n spesifieke taak te verrig. Die doel van hierdie navorsing is om 'n sistematiese benadering, om die beste kandidate vir lugruimbeheerderposisies in Saoedi Arabië te identifiseer, te ontwikkel. Drie geïntegreerde metodes is ingespan vir die besluitneming in hierdie studie. Eerstens is 'n wasige besluitnemingsboom toegepas om die kriteria gewigte te bepaal. Daarna is die wasige tegniek van Orde Voorkeur deur Ooreenkoms tot die Ideale Oplossing toegepas om die kenmerke te rangskik. Laastens is die Data Omvangs Analise gebruik om die kwalitatiewe veranderlikes tot kwantitatiewe gelykhede om te skakel. 'n Peiling is onder nasionale en internasionale besluitnemers geneem om die noodsaaklike inligting rakende die kriteria en sub-kriteria van die lugruimbeheerstelsel te bepaal. Die besluitnemingsvraagstuk is geformuleer deur vyf kriteria en tien aansoekers in te span. Die verhouding tussen die wasige Orde Voorkeur deur Ooreenkoms tot die Ideale Oplossing en wasig-geweegde gemiddeld was besonder positief vir besluitneming. Die resultate van die wasige Orde Voorkeur deur Ooreenkoms tot die Ideale Oplossing en die Data Omvangs Analise moedig die ontwikkeling van 'n besluitneming ondersteuningstelsel vir lugruimbeheerders aan. <![CDATA[<b>Investigating the financial close of projects within the South African Renewable Energy Independent Power Producer Procurement Programme</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S2224-78902014000300007&lng=pt&nrm=iso&tlng=pt South Africa may have a generation capacity shortage in the near future. The Renewable Energy Independent Power Producer Procurement Programme (REIPPPP) is playing an important role in creating generation capacity to fulfil future demand requirements. This investigation focused primarily on identifying the problems that have been experienced with projects in the programme (e.g., to reach financial close). The research showed that there is good alignment between the requirements in the request for proposals and those from financiers. Several issues caused delays in projects reaching financial close. However, respondents to this study indicated that the REIPPPP is well thought out and that several problems are being addressed successfully.<hr/>Suid-Afrika kan in die nabye toekoms 'n tekort aan elektrisiteit opwekkingsvermoë ervaar. Die regering se onafhanklike kragopwekkers groenkrag-aankoopprogram - of te wel die REIPPPP - speel 'n belangrike rol in die skep van opwekkingsvermoë om aan toekomstige aanvraag vereistes te voldoen. Hierdie navorsing het primer gefokus op die identifisering van die probleme wat ondervind is deur projekte in die program - spesifiek met finansiële sluiting. Dié navorsing toon dat daar 'n goeie korrelasie tussen die vereistes van die regering - in die navrae na voorstelle - en dié van finansierders is. Verskeie probleme het vertragings in finansiële sluiting van projekte veroorsaak. Tog dui respondente van hierdie studie aan dat die program goed deurdag is en dat verskeie probleme suksesvol aangespreek word. <![CDATA[<b>An automatic fixture design system for creating prismatic parts</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S2224-78902014000300008&lng=pt&nrm=iso&tlng=pt A modular fixture system is a flexible alternative to a dedicated fixture. In this paper, an automatic modular fixture design system is suggested for creating prismatic parts. The system contains fixture planning, fixture modelling, and fixture assembly. The part geometrical database and process plans are considered as inputs to the system. A rule-based method is applied to assign the feasible locating scheme and the locating and clamping datum. The search strategy is designed to determine the most suitable locating and clamping points. The final fixture assembly is made with the standard fixture components using the CATVBA Editor inside CATIAV5. The proposed methodology is successfully validated with a case study.<hr/>'n Aanpasbare hegtingsisteem is 'n buigsame alternatief vir 'n toegewyde hegstuk. 'n Outomatiese aanpasbare hegstuk ontwerpsisteem vir die skep van prismatiese onderdele word voorgestel. Die sisteem bevat hegstuk beplanning, hegstuk modellering en hegstuk samestelling. Die onderdeel geometriese databasis en proses planne word as insette gebruik. A reëlgebaseerde metode is toegepas om die opsporings en vasklem verwysingspunte toe te ken. Die soekstrategie is ontwerp om die mees geskikte verwysings-en klempunte te bepaal. Die finale hegstuk samestelling is gemaak van die standaard hegstuk komponente van die CATVBA Editor van CATIAV5. Die voorgestelde benadering is suksesvol gevalideer deur middel van 'n gevallestudie. <![CDATA[<b>A fuzzy-based particle swarm optimisation approach for task assignment in home healthcare</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S2224-78902014000300009&lng=pt&nrm=iso&tlng=pt Home healthcare (HHC) organisations provide coordinated healthcare services to patients at their homes. Motivated by the ever-increasing need for home-based care, the assignment of tasks to available healthcare staff is a common and complex problem in homecare organisations. Designing high quality task schedules is critical for improving worker morale, job satisfaction, service efficiency, service quality, and competitiveness over the long term. The desire is to provide high quality task assignment schedules that satisfy the patient, the care worker, and the management. This translates to maximising schedule fairness in terms of workload assignments, avoiding task time window violation, and meeting management goals as much as possible. However, in practice, these desires are often subjective as they involve imprecise human perceptions. This paper develops a fuzzy multi-criteria particle swarm optimisation (FPSO) approach for task assignment in a home healthcare setting in a fuzzy environment. The proposed approach uses a fuzzy evaluation method from a multi-criteria point of view. Results from illustrative computational experiments show that the approach is promising.<hr/>Tuisversorgingsorganisasies verskaf gekoördineerde gesondheidsorg dienste aan pasiënte by hul wonings. Gegee die toenemende behoefte aan tuisversorging, is die uitdeel van take tot die beskikbare gesondheidsorg personeel 'n algemene en komplekse probleem in tuisversorgingsorganisasies. Die ontwerp van hoë gehalte taak skedules is van kritieke belang vir die verbetering van werker moraal, werktevredenheid, diens doeltreffendheid, gehalte van diens en mededingendheid oor die lang termyn. Die doel is om hoë gehalte taakaanwysingskedules aan die pasiënt, die versorger en die bestuur te voorsien. Dit kom neer op die maksimering van skedule regverdigheid ten opsigte van werklading, vermyding van taak tyd venster oortreding asook die bereiking van meeste bestuursdoelwitte. In die praktyk is hierdie doelstellings dikwels subjektief as dit vae persepsies behels. Hierdie studie ontwikkel 'n wasige multi-kriteria partikel swerm optimisering benadering vir taakaanwysing in 'n tuisversorgingsorganisasie in 'n wasige omgewing. Die voorgestelde benadering gebruik 'n wasige metode van evaluering vanuit 'n multi-kriteria oogpunt. Resultate van illustratiewe simulasie eksperimente toon dat die benadering belowend is. <![CDATA[<b>Developing a tool for project contingency estimation in a large portfolio of construction projects</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S2224-78902014000300010&lng=pt&nrm=iso&tlng=pt To enable the management of project-related risk on a portfolio level in an owner organisation, project contingency estimation should be performed consistently and objectively. This article discusses the development of a contingency estimation tool for a large portfolio that contains similar construction projects. The purpose of developing this tool is to decrease the influence of subjectivity on contingency estimation methods throughout the project life cycle, thereby enabling consistent reflection on project risk at the portfolio level. Our research contribution is the delivery of a hybrid tool that incorporates both neural network modelling of systemic risks and expected value analysis of project-specific risks. The neural network is trained using historical project data, supported by data obtained from interviews with project managers. Expected value analysis is achieved in a risk register format employing a binomial distribution to estimate the number of risks expected. By following this approach, the contingency estimation tool can be used without expert knowledge of project risk management. In addition, this approach can provide contingency cost and duration output on a project level, and it contains both systemic and project-specific risks in a single tool.<hr/>Projek-gebeurlikheidsreserwes moet konsekwent en objektief beraam word ten einde die bestuur van projek-verwante risiko op portefeuljevlak in eienaar-organisasies moontlik te maak. Hierdie artikel bespreek die ontwikkeling van 'n gebeurlikheidsreserwe-beramer vir 'n portefeulje met baie konstruksieprojekte wat almal 'n soortgelyke aard het. Die doel met die ontwikkeling van hierdie funksie is om die invloed van subjektiwiteit op gebeurlikheidsreserwe-beramingmetodes deur die volledige projeklewensiklus te verminder en daardeur projekrisiko konsekwent op portefeuljevlak te weerspieël. Die navorsingsbydrae is die lewering van 'n hibriede funksie wat beide neurale netwerk modellering van sistemiese risiko en die verwagte waarde-ontleding van projek-spesifieke risikos insluit. Die neurale netwerk word geleer deur historiese projekdata te gebruik, tesame met ondersteunende data wat deur onderhoude met projekbestuurders verkry is. Die verwagte waarde-ontleding word deur 'n risiko-register formaat bewerkstellig, wat die aantal verwagte risikos met 'n binomiaalverdeling beraam. Deur hierdie benadering te volg kan die gebeurlikheidsreserwe-beramingfunksie gebruik word sonder diepte-kennis van risikobestuur in projekte. Dit verskaf gebeurlikheidkoste en -tydsduur beramings op projekvlak, en bevat beide sistemiese risiko en projek-spesifieke risiko in 'n enkele funksie. <![CDATA[<b>The development of co-curricular interventions to strengthen female engineering students' sense of self-efficacy and to improve the retention of women in traditionally male-dominated disciplines and careers</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S2224-78902014000300011&lng=pt&nrm=iso&tlng=pt Self-efficacy relates to positive outcomes for women studying and working in traditionally male-dominated fields such as engineering, science, and technology. Many women engineering students (WES) experience fear and insecurity about how they will be treated and perceived in this traditionally male-dominated field, either as a WES or as a working engineer. This study provides support for the development of co-curricular interventions to improve the self-efficacy of WES at a South African tertiary institution. The research design for this study is based on a phenomenological approach that uses a process of critical analysis of evaluation and feedback documents relating to the various co-curricular interventions and their perceived influence on selected WES's self-efficacy. Finally, as there has been no other South African research on WES and the sources of self-efficacy, this research is unique in the South African context.<hr/>Daar is 'n verband tussen selfdoeltreffendheid en positiewe resultate vir vroue wat studeer en werk in tradisionele mansgedomineerde dissiplines, soos ingenieurswese. Daar is egter baie vroulike ingenieurswese studente wat vrese en onsekerhede ervaar oor hoe hulle behandel en waargeneem sal word in 'n tradisionele, mansgedomineerde dissipline, hetsy as student of as werkende ingenieur. Hierdie navorsingstudie bied ondersteuning vir die ontwikkeling van mede-kurrikulêre ingrypings om die selfdoeltreffendheid van vroue studente in ingenieurswese aan 'n Suid-Afrikaanse tersiêre instelling te verbeter. Die navorsing in hierdie studie is gebaseer op 'n fenomenologiese benadering, en gebruik 'n proses van kritiese ontleding van evaluering en terugvoer dokumente van verskillende mede-kurrikulêre ingrypings, en die invloed daarvan op geselekteerde vroue ingenieurstudente se selfdoeltreffendheid. Ten slotte, aangesien geen ander Suid-Afrikaanse navorsing oor selfdoeltreffendheid en vroulike ingenieurswese studente gevind kon word nie, is hierdie studie uniek in die Suid-Afrikaanse konteks. <![CDATA[<b>A farm site development method: Creating a roadmap towards site saturation</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S2224-78902014000300012&lng=pt&nrm=iso&tlng=pt Agricultural engineering applies existing knowledge to provide for humanity's greatest need: food for survival. This article presents an opportunity to augment existing agricultural engineering practices with industrial engineering techniques, with the aim of encouraging financial control during the expansion of assets on farms. Facility planning techniques are combined with a well-known enterprise engineering technique, the transformation roadmap, to develop a Farm Site Development Method (FSDM). The purpose of the FSDM is to provide method guidance in developing a facilities master plan to evolve farm facilities in a phased approach towards a future/saturation state. The article also presents an evaluation of the FSDM, via a practical demonstration at Waterfall Farm.<hr/>Landbou-ingenieurswese gebruik bestaande kennis om aan een van die mensdom se grootste behoeftes te voldoen: voedsel vir oorlewing. Die geleentheid om bestaande landbou-ingenieurswese praktyke aan te vul met bedryfsingenieurswese tegnieke wat finansiële beheer aanmoedig tydens bate-uitbreidings op plase, word hier aangebied. Fasiliteitsbeplannings-tegnieke word gekombineer met 'n welbekende ondernemingsingenieurswese tegniek, die transformasie padkaart, met die ontwikkeling van 'n plaasterrein ontwikkelingsmetode (PTOM). Die doel van die PTOM is om metodiese leiding te bied aan die ontwikkeling van 'n meester-fasiliteitsplan ten einde die plaas se fasiliteite in fases te ontwikkel tot 'n toekomstige-/versadigingstatus. Die studie bied ook 'n evaluasie van die PTOM aan, in die vorm van 'n praktiese demonstrasie by Waterfall Farm. <![CDATA[<b>A new multivariate nonlinear model to handle the volatility transmission</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S2224-78902014000300013&lng=pt&nrm=iso&tlng=pt Price volatility of stocks is an important issue in stock markets. It should also be taken into account that the stochastic nature of volatility affects decision-makers' minds to a great extent. Therefore, predicting price volatility could help them make proper decisions. In this paper, a new multivariate fractionally integrated generalised autoregressive conditional heteroscedasticity (MFIGARCH) model is proposed to handle the price volatility in stocks. In this model, a long-term parameter is considered and estimated along with other parameters. In estimating the parameters of this nonlinear model, the maximum likelihood estimation method, which could be solved by standard econometric packages, is applied. However, these packages are no longer efficient when the size of the model increases. Thus meta-heuristic approaches, which stochastically seek optimal or near-optimal solutions, were used. In this paper, the well-known Particle Swarm Optimisation (PSO) meta-heuristic method is used for solving the suggested multivariate FIGARCH model. Hence the main objective of this paper is to introduce a new model for addressing the stock price volatility (i.e., the development of FIGARCH to create the MFIGARCH model) and to apply an efficient estimation method (i.e. PSO) for finding the parameters of the problem.<hr/>Die wisselvalligheid van die aandeelprys is 'n belangrike kwessie vir aandelemarkte. Die stogastiese aard van dié wisselvalligheid beïnvloed besluitnemers op 'n groot skaal en die voorspelling van die wisselvalligheid kan die besluitneming verbeter. 'n Nuwe, meerveranderlike gedeeltelik geïntegreerde veralgemeende outoregressiewe voorwaardelike heteroskedastisiteit (MFIGARCH) model word voorgestel om die wisselvalligheid in aandeelpryse te hanteer. In hierdie model word, onder andere, 'n langtermyn parameter oorweeg en beraam. Vir die beraming van parameters in hierdie nie-lineêre model word die maksimum waarskynlikheidsmetode (wat opgelos kan word deur middel van standaard ekonometriese pakkette) toegepas. Hierdie pakkette is egter oneffektief wanneer die model vergroot. Dus word meta-heuristiese, wat optimale of bynaoptimale oplossings stogasties soek, ingespan. Die welbekende partikel swerm optimering metode word gebruik vir die oplos van die voorgestelde meerveranderlike model. Die hoof doel van hierdie studie is om die nuwe meerveranderlike model om die wisselvalligheid in aandeelprys aan te spreek, bekend te stel en om effektiewe parameter beraming deur middel van partikel swerm optimering toe te pas. <![CDATA[<b>Prioritising maintenance improvement opportunities in Physical Asset Management</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S2224-78902014000300014&lng=pt&nrm=iso&tlng=pt Physical Asset Management (PAM) initiatives suffer many barriers in implementation that can hinder their influence and sustainability. One of these barriers is the lack of buy-in from all levels in the organisation, due to a lack of understanding of the perceived benefits of PAM. Organisational alignment in a PAM project is achieved by aligning employees' views on the deficient areas in the organisation, and managing their expectations of the perceived benefits of a good application of PAM. Barriers in implementation are created, however, by the lack of a transparent method for conveying the significance of critical areas in the system and by an unclear way of communicating these problems. Typically these initiatives are constrained by available resources. In order for PAM initiatives to be successful, there first needs to be an alignment in the execution through a clear understanding of which assets are critical, so that resources can be allocated effectively. In this study, this problem is thoroughly examined, and a method is sought that seeks to isolate the effects of the maintenance function in an operation and to uncover critical areas. A study is performed on the methods that are typically used to create such understanding. This study highlights the shortcomings of these methods, which limit their applicability. A new methodology is therefore created in order to overcome these problems. The methodology is validated through a case study, where it shown to be highly beneficial in uncovering critical areas and achieving organisational alignment through the communication of results.<hr/>Fisiese batebestuursinisiatiewe het verskeie implementeringstekortkominge wat hulle invloed en volhoubaarheid verhinder. Een van hierdie hindernisse is die gebrek aan ondersteuning van alle vlakke in die organisasie. Dit is as gevolg van 'n gebrekkige begrip van die voordele van batebestuur. Organisatoriese belyning by 'n batebestuursprojek word bereik deur almal te belyn oor wat die gebrekkige areas is, en om hulle verwagtinge oor die voordele te bestuur. Metodes om op 'n deursigtige wyse die kritieke areas aan te dui en te kommunikeer, ontbreek. Dit belemmer die uitvoer van projekte en die afwesigheid van empiriese bewyse van probleme, skep 'n afhanklikheid van argumentatiewe menings wat dikwels verskil. Inisiatiewe word dikwels beperk deur die beskikbaarheid van hulpbronne, en 'n effektiewe toedeling van beskikbare hulpbronne is dus noodsaaklik. Om 'n suksesvolle batebestuursprojek dus uit te voer, moet daar eers 'n duidelike begrip en ooreenstemming wees oor wat die verskeie kritieke areas is wat die meeste aandag verlang, sodat hulpbronne doeltreffend toegeken kan word. In dié studie word hierdie probleem ondersoek deur oplossings na te vors. 'n Metode is gesoek wat daarop gemik is om die gevolge van batebestuur te isoleer in 'n produksiestelsel en kritiese areas te ontbloot. 'n Studie is uitgevoer op metodes wat gebruik word om sodanige analises uit te voer. Dit word gewys dat huidige metodes tekortkominge het wat die toepaslikheid beperk. 'n Nuwe metode is geskep wat gebruik maak van simulasie om hierdie probleme te oorkom. Die metode is gevalideer deur 'n gevallestudie, waar dit bevestig is dat die metode voordelig is om kritiese areas te ontbloot en om organisatoriese belyning te bewerkstellig deur effektiewe kommunikasie van die resultate. <![CDATA[<b>The number of pickers and stock-keeping unit arrangement on a unidirectional picking line</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S2224-78902014000300015&lng=pt&nrm=iso&tlng=pt The order picking process is often the single largest expense in a distribution centre (DC). The DC considered in this paper uses a picking line configuration to perform order picking. The number of pickers in a picking line, and the initial arrangement of stock-keeping units (SKUs), are two important factors that affect the total completion time of the picking lines. In this paper, the picking line configuration is simulated with an agent-based approach to describe the behaviour of an individual picker. The simulation is then used to analyse the effect of the number of pickers and the SKU arrangement. Verification and validation of this model shows that the model represents the real-world picking line to a satisfactory degree. Marginal analysis (MA) was chosen to determine a 'good' number of pickers by means of the simulation model. A look-up table is presented to provide decision support for the choice of a 'good' number of pickers to improve completion times of the picking line, for the properties of a specific picking line. The initial SKU arrangement on a picking line is shown to be a factor that can affect the level of picker congestion and the total completion time. The greedy ranking and partitioning (GRP) and organ pipe arrangement (OPA) techniques from the literature, as well as the historical SKU arrangements used by the retailer under consideration, were compared with the proposed classroom discipline heuristic (CDH) for SKU arrangement. It was found that the CDH provides an more even spread of SKUs that are picked most frequently, thus decreasing congestion and total completion time.<hr/>Die opmaak van bestellings is meestal die enkele grootste uitgawe in n distribusiesentrum (DS). Die DS wat hier beskou word gebruik n opstelling in die vorm van 'n uitsoeklyn om bestellings vir die winkels op te maak. Die aantal werkers en die rangskikking van voorraadeenhede in die uitsoeklyn is twee belangrike faktore wat die totale afhandelingstyd beïnvloed. In hierdie artikel word 'n uitsoeklyn met behulp van agent-gebaseerde simulasie gemodelleer om die gedrag van n individuele werker te simuleer. Hierdie simulasie word dan gebruik om die effek van die aantal werkers en die voorraad se rangskikking te analiseer. Verifiëring en validering van die model wys dat die model wel die werklike uitsoeklyn bevredigend naboots. Grensontleding word gebruik om 'n goeie aantal werkers vir n uitsoeklyn te bepaal. n Tabel word verskaf om die regte aantal werkers vir n nuwe lyn na te slaan. Die aanvanklike rangskikking van die voorraadeenhede in die uitsoeklyn beïnlvoed die kongestie en die totale afhandelingstyd. Die gulsige rangskikkingen-verdeling en die orrelpyp rankskikkings uit die literatuur, sowel as die historiese rankskikking deur die kleinhandelaar, word vergelyk met die voorgestelde klaskamer-dissipline-heuristiek (KDH) vir voorraad rangskikking. Die bevinding word gemaak dat die KDH n beter verspreiding van voorraadeenhede oor die lyn bewerkstellig, wat lei tot die verlaging van die totale kongestie en afhandelingstyd van n uitsoeklyn. <![CDATA[<b>A multi-dimensional method for evaluating a product's conceptual schemes</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S2224-78902014000300016&lng=pt&nrm=iso&tlng=pt The use of conceptual scheme evaluation is a key step in the development of new products. In this paper, a multi-dimensional evaluation method that involves subjective evaluation, eye-tracking, and product image evaluation is established. In this study, subjective evaluation is used to test customers' initial reactions to conceptual schemes, and eye-tracking is used to highlight the features of conceptual schemes that are most attractive to customers. With the help of Kansei engineering, the most attractive features of a particular product are described and clarified from the product image evaluation. This multidimensional method can be applied not only in screening conceptual schemes, but also in exploring the reasons and suggestions for product improvement. The method was assessed in this study through a case study evaluation of conceptual design schemes for a mobile phone.<hr/>Die gebruik van konseptuele skema beoordeling is ‘n sleutel stap in die ontwikkel van nuwe produkte. ‘n Multidimensionele beoordelingsmetode, wat subjektiewe beoordeling, die volg van oog beweging en produk beeld beoordeling behels, is ontwikkel. Subjektiewe beoordeling word gebruik om kliënte se aanvanklike reaksies op konseptuele skemas te toets. Die volg van oog beweging word gebruik om die mees aantreklike eienskappe van konseptuele skemas uit te lig. Met die hulp van Kansei ingenieurswese word die mees aantreklike eienskappe van ‘n spesifieke produk beskryf en duidelik gemaak vanuit die produk beeld beoordeling. Hierdie multidimensionele metode kan ook toegepas word in die motiverings en aanbevelings vir produk verbetering. Dié metode is beoordeel deur ‘n gevallestudie van konseptuele ontwerpskemas van ‘n selfoon. <![CDATA[<b>Towards the implementation of e-manufacturing: Design of an automatic tea drying control system</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S2224-78902014000300017&lng=pt&nrm=iso&tlng=pt Many of the production costs for producing tea are attributable to the process of drying the tea. E-manufacturing can assist companies to reduce these production costs by making crucial information available to decision-makers so that they can make informed decisions. This paper presents an application of e-manufacturing to the design of an automatic tea drying control system. This control system will ensure that the multiple drying parameters such as temperature, dryer-exit tea moisture content, and fuel consumption are maintained at optimal states during the course of the drying of tea. The additional aim of this system is to balance the cost of production and the quality of the final product. Using the Guggenheim-Anderson-De Boer (GAB) model, the optimum drying temperature was found to be 100-110°C, while maintaining a dryer-exit tea moisture content of 3 to 3.12 per cent, at a drying rate of 3 per cent per minute. A Barix control application to control the system's activities, using the web user interface (WUI), was also developed.<hr/>'n Groot gedeelte van die koste in die produksie van tee is as gevolg van die tee-droogproses. E-vervaardiging kan die produksiekoste verminder deur kritiese inligting vir die besluitnemers beskikbaar te stel. Hierdie studie beskryf 'n toepassing van e-vervaardiging op die ontwerp van 'n outomatiese tee-droog beheerstelsel. Die beheerstelsel verseker dat al die droogparameters, soos temperatuur, voggehalte en brandstofverbruik, by optimum toestande beheer word deur die loop van die droogproses. Verder word daar deur die beheerstelsel 'n balans tussen die produksiekoste en die gehalte van die finale produk gehandhaaf. Deur van die Guggenheim-Anderson-De Boer (GAB) model gebruik te maak, is die optimale droogtemperatuur gevind om tussen 100 tot 110°C te lê, terwyl die droëruitlaatvoggehalte tussen 3 en 3.12% met 'n droogtempo van 3% per minuut te lê. 'n Barix beheer program is ontwikkel om die beheerstelsel se werksaamhede te monitor. <![CDATA[<b>Moving from job-shop to production cells without losing flexibility: A case study from the wooden frames industry</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S2224-78902014000300018&lng=pt&nrm=iso&tlng=pt Cellular production is usually seen as a hybrid approach between job-shop and flow-line paradigms, reducing the major disadvantages of these two paradigms: the low productivity of job-shops and the low flexibility (in terms of products' variety) of the flow-lines. This paper describes the implementation of a production cell in a production unit of wood-framed pictures and mirrors, which was originally configured as a traditional job-shop, without losing the necessary flexibility to face market demand and simultaneously increasing the production unit's performance. By implementing a highly flexible cell, very significant improvements were expected for the system's overall performance and the quality of the products. These expectations were met, and the implementation was successful, as demonstrated by the results presented.<hr/>Sellulêre produksie word gewoonlik gesien as 'n kombinasie van werkswinkel en vloeilyn benaderings en in die proses word die groot nadele van beide die benaderings, naamlik die lae produktiwiteit van werkswinkels en die lae aanpasbaarheid (in terme van produk variëteit) van vloeilyne, verminder. Die implementering van 'n produksie sel in 'n houtraamvervaardigingsaanleg, wat aanvanklik as 'n tradisionele werkswinkel uitgelê is, word beskryf. Hierdie implementering vind plaas sonder om die aanleg se aanpasbaarheid te beïnvloed terwyl die produktiwiteit verhoog word. Deur 'n hoogs aanpasbare produksie sel te implementeer word noemenswaardige verbeteringe in die sisteem se algehele verrigting en gehalte verwag. Hierdie verwagtinge is inderdaad bereik en die implementering is dus as suksesvol beskou. <![CDATA[<b>Great gap between customers' taste and market variety in the car market in Iran</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S2224-78902014000300019&lng=pt&nrm=iso&tlng=pt Hierdie studie beskryf voertuie met verskillende faktore wat uit meerdere vlakke bestaan. Die kliënt tevredenheid word bepaal deur die vlakke van die faktore en die voertuig se prys. Twee kliëntgroepe met verskillende voorkeure is in die voertuigmark in Iran geïdentifiseer. Die twee groepe beslaan 82.4 persent van die kliënte. Gegrond op die waardes van die faktore word die waarde van elke voertuig vir elke groep bepaal. Die doel van hierdie navorsing is om beter kliënt voorkeure te verstaan om sodoende die markaandeel van die voertuie te bepaal en dus aan die kliëntebasis se vereistes beter te voldoen. Met hierdie inligting kan vervaardigers beter strategieë en produksie planne beraam en sodoende hul markaandeel vergroot. Elke groep is bepaal gegrond op hul eienskappe soos geslag, ouderdom en opvoeding. Tirole en Gabszewicz en Thisse se teorieë is gebruik om die markaandeel volgens die kliënte se vereistes te bepaal. Hierdie navorsing se bydrae is 'n veralgemening van Tirole se produk differensiasie vir die geval waar die paargewyse rangskikking van produkte 'n asikliese netwerk vorm. The beraamde vraag is vergelyk met verkoopsdata van die laaste vyf jaar. 'n Groot gaping tussen die voertuigverkope en die kliënte vereistes in Iran is waargeneem.