Scielo RSS <![CDATA[South African Journal of Industrial Engineering]]> http://www.scielo.org.za/rss.php?pid=2224-789020150002&lang=pt vol. 26 num. 2 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=S2224-78902015000200001&lng=pt&nrm=iso&tlng=pt <![CDATA[<b>The development of the industrial engineering profession in South Africa</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S2224-78902015000200002&lng=pt&nrm=iso&tlng=pt <![CDATA[<b>An evaluation of the effectiveness of observation camera placement within the MeerKAT radio telescope project</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S2224-78902015000200003&lng=pt&nrm=iso&tlng=pt A recent development within the MeerKAT sub-project of the Square Kilometre Array radio telescope network was the placement of a network of three observation cameras in pursuit of two specific visibility objectives. In this paper, we evaluate the effectiveness of the locations of the MeerKAT observation camera network according to a novel multi-objective geographic information systems-based facility location framework. We find that the configuration chosen and implemented by the MeerKAT decision-makers is of very high quality, although we are able to uncover slightly superior alternative placement configurations. A significant amount of time and effort could, however, have been saved in the process of choosing the appropriate camera sites, had our solutions been available to the decision-makers.<hr/>'n Onlangse ontwikkeling binne die MeerKAT deelprojek van die Vierkante Kilometer Skikking radio teleskoop netwerk was die plasing van 'n netwerk van drie waarnemingskameras volgens twee spesifieke sigbaarheidsdoelstellings. In hierdie artikel evalueer ons die doeltreffendheid van die liggings van hierdie kameranetwerk volgens 'n nuwe, veeldoelige geografiese inligtingstelsel-gebaseerde fasiliteitsplasing raamwerk. Ons vind dat die plasingskonfigurasie wat deur die MeerKAT besluitnemers gekies is, van baie hoë kwaliteit is, alhoewel ons daartoe in staat is om plasingskonfigurasies van effens hoër kwaliteit te bereken. 'n Beduidende hoeveelheid tyd en moeite kon egter gedurende die besluitnemingsproses gespaar gewees het indien ons oplossings aan die besluitnemers beskikbaar was. <![CDATA[<b>The effect of the emergency medical services vehicle location and response strategy on response times</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S2224-78902015000200004&lng=pt&nrm=iso&tlng=pt Response time is currently considered to be an important performance indicator in Emergency Medical Services (EMS) systems. A number of factors may affect response times, including the location of emergency vehicles and the type of response system design used. This study aimed to assess the effects of emergency vehicle location and response system design on response time performance in a model of a large South African urban EMS system, using discrete-event simulation. Results indicated that both the emergency vehicle location and response system design factors had a significant effect on response time performance, with more decentralised vehicle location having a greater effect.<hr/>Reaksietyd word tans beskou as 'n belangrike prestasie-indikator in mediese nooddienste sisteme. Verskeie faktore mag die reaksietyd beïnvloed. Die doel van die studie is om die effek van die ligging van noodvoertuie en die tipe reaksie-sisteemontwerp op die reaksietyd te ondersoek binne die konteks van 'n Suid Afrikaanse stedelike gebied deur gebruik te maak van diskrete-gebeurtenis simulasie. Resultate dui daarop dat beide die ligging van noodvoertuie en die reaksie-sisteemontwerp die reaksietyd beïnvloed. Hoe meer gedesentraliseer die voertuie se plasing was, hoe beter was die effek op die reaksietyd. <![CDATA[<b>Integrated model for supplier selection and performance evaluation</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S2224-78902015000200005&lng=pt&nrm=iso&tlng=pt This paper puts forward a model for selecting suppliers and evaluating the performance of those already working with a company. A simulation was conducted in a food industry. This sector has high significance in the economy of Brazil. The model enables the phases of selecting and evaluating suppliers to be integrated. This is important so that a company can have partnerships with suppliers who are able to meet their needs. Additionally, a group method is used to enable managers who will be affected by this decision to take part in the selection stage. Finally, the classes resulting from the performance evaluation are shown to support the contractor in choosing the most appropriate relationship with its suppliers.<hr/>'n Model vir die seleksie van leweransiers en vir die beoordeling van dié wat alreeds aan die maatskappy verbonde is, word voorgestel. 'n Simulasie van die voedselindustrie in Brasilië is gedoen, omdat hierdie sektor 'n belangrike rol in die Brasiliaanse ekonomie speel. Die model integreer die leweransierseleksie- en beoordeelfases; dit is belangrik sodat 'n maatskappy vennootskappe met leweransiers, wat aan die maatskappy se vereistes voldoen, kan aangaan. Verder word 'n groepmetode gebruik om belanghebbende bestuurders toe te laat om insette tot die besluitneming tydens die leweransierseleksiefase te lewer. Laastens word terugvoer van die leweransierbeoordeelfase gebruik om die maatskappy te steun in die keuse van 'n gepaste verhouding met sy leweransiers. <![CDATA[<b>Discussing and evaluating green supply chain suppliers: A case study of the printed circuit board industry in China</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S2224-78902015000200006&lng=pt&nrm=iso&tlng=pt Green supply-chain management is a novel idea that incorporates the concept of environmental protection into traditional supply-chain management in order to reduce environmental risks and impact. This study developed criteria for evaluating green suppliers on the basis of the green supply chain. The Decision-Making Trial and Evaluation Laboratory (DEMATEL) method was adopted to investigate the criteria for evaluating green suppliers, to explore inter criterion causal relationships and levels of mutual influence, and finally to discuss the mechanism for evaluating green suppliers, as well as the methods for selecting them.<hr/>Groen voorsieningskettingbestuur is 'n nuwe idee wat die konsep van omgewingsbeskerming tot tradisionele voorsieningskettingbestuur byvoeg om sodoende die omgewingsrisiko's en -impak verminder. Dié studie het 'n kriteria vir die beoordeling van groen verskaffers op grond van die groen voorsieningsketting ontwikkel. Die "Decision-Making Trial and Evaluation Laboratory" (DEMATEL) metode is aangepas om die kriteria vir die beoordeling van groen verskaffers te ondersoek, om die onderlinge maatstaf oorsaaklike verhoudings en vlakke van wedersydse invloed te ondersoek en om die meganisme vir die beoordeling van groen verskaffers en die metodes om hulle te kies, word bespreek. <![CDATA[<b>A strategic framework for improbable circumstances</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S2224-78902015000200007&lng=pt&nrm=iso&tlng=pt Rare events, known as 'Black Swans', have determined the course of history. One of these was the global economic crisis of 2008. Such events highlight fields like strategic management and their shortcomings in helping to prepare organisations. The Strategic Framework for Improbable Circumstances was designed to add to the strategic management process by improving organisational preparation for these rare events. The framework was validated through interviews with experts who showed the need for such a framework, and who confirmed that it is a good first step for organisations to take towards addressing these Black Swan events.<hr/>Rare gebeurtenisse, ook bekend as 'Swart Swane', het die verloop van die verlede bepaal. Een van hierdie gebeurtenisse was die wêreldwye ekonomiese krisis van 2008. Hierdie Swart Swane het die fokus geplaas op strategiese bestuur, en op die tekortkominge van hierdie studieveld om besighede beter voor te berei om Swart Swane beter te hanteer. Die Strategiese Raamwerk vir Onwaarskynlike Omstandighede is ontwikkel as 'n byvoeging tot die strategiese bestuursproses deur die organisasie se voorbereiding vir hierdie tipe gebeurtenisse te verbeter. Die validasie van die raamwerk was gedoen deur onderhoude met deskundiges wat bewys het dat so raamwerk benodig word, en uitgewys het dat dit 'n goeie eerste stap was vir besighede om Swart Swane te trotseer. <![CDATA[<b>Implementing the South African additive manufacturing technology roadmap - the role of an additive manufacturing centre of competence</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S2224-78902015000200008&lng=pt&nrm=iso&tlng=pt The Rapid Product Development Association of South Africa (RAPDASA) expressed the need for a national Additive Manufacturing Roadmap. Consequentially, the South African Department of Science and Technology commissioned the development of a South African Additive Manufacturing Technology Roadmap. This was intended to guide role-players in identifying business opportunities, addressing technology gaps, focusing development programmes, and informing investment decisions that would enable local companies and industry sectors to become global leaders in selected areas of additive manufacturing. The challenge remains now for South Africa to decide on an implementation approach that will maximize the impact in the shortest possible time. This article introduces the concept of a national Additive Manufacturing Centre of Competence (AMCoC) as a primary implementation vehicle for the roadmap. The support of the current leading players in additive manufacturing in South Africa for such a centre of competence is shared and their key roles are indicated. A summary of the investments that the leading players have already made in the focus areas of the AMCoC over the past two decades is given as confirmation of their commitment towards the advancement of the additive manufacturing technology. An exposition is given of how the AMCoC could indeed become the primary initiative for achieving the agreed national goals on additive manufacturing. The conclusion is that investment by public and private institutions in an AMCoC would be the next step towards ensuring South Africa's continued progress in the field.<hr/>Die "Rapid Product Development Association of South Africa" (RAPDASA) het die behoefte aan 'n nasionale toevoegingsvervaardigingpadkaart uitgelig. Gevolglik het die Departement van Wetenskap en Tegnologie opdrag vir die ontwikkel van so 'n padkaart gegee. Hierdie was veronderstel om rolspelers te lei in die identifisering van besigheidsgeleenthede, die aanspreek van tegnologie tekortkominge, die fokus op ontwikkelingsprogramme en om beleggingsbesluite te beïnvloed wat plaaslike maatskappye en industrieë in staat sal stel om wêreldleiers op uitgekose areas van toevoegingsvervaardiging te word. Die uitdaging vir Suid-Afrika is nou op 'n toepassingsbenadering wat die maksimum impak in die kortste moontlike tyd sal verseker. Hierdie artikel stel die konsep van 'n nasionale Toevoegingsvervaardiging Sentrum van Bevoegdheid as 'n primêre toepassing van die padkaart voor. Die ondersteuning deur die hoof rolspelers in Suid-Afrika vir so 'n sentrum word gedeel en hulle onderskeie rolle is aangedui. Die rolspelers se toewyding word gestaaf aan die hand van hul beleggings in die fokus areas van die Sentrum oor die laaste twee dekades. 'n Uiteensetting word verskaf van hoe die Sentrum inderdaad die hoof inisiatief vir die behaal van die ooreengekome nasionale doelstellings kan word. Die gevolgtrekking is dat belegging deur die publieke en privaat instansies in so 'n sentrum die volgende stap tot die versekering van Suid-Afrika se voortgesette vordering in veld is. <![CDATA[<b>Heat treatment of Ti-6Al-4V produced by lasercusing</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S2224-78902015000200009&lng=pt&nrm=iso&tlng=pt LaserCUSING® is a selective laser melting (SLM) process that is capable of manufacturing parts by melting powder with heat input from a laser beam. LaserCUSING demonstrates potential for producing the intricate geometries specifically required for biomedical implants and aerospace applications. One main limitation to this form of rapid prototyping is the lack of published studies on the material performance of the resulting material. Studies of the material's performance are often complicated by dependence on several factors, including starting powder properties, laser parameters, and post-processing heat treatments. This study aims to investigate the mechanical properties of LaserCUSING-produced Ti-6Al-4V and its performance relative to the conventional wrought counterpart. A combination of conventional and LaserCUSING-tailored heat treatments is performed. The resulting microstructures are studied and linked to the properties obtained from hardness tests. The findings highlight that LaserCused Ti-6Al-4V is competitive with traditional materials, provided that optimal parameters are chosen and parts are subject to tailored post-processing. In the as-built condition, LaserCused Ti-6Al-4V displays superior strength and hardness as a result of a martensitic microstructure, and a poorer performance in ductility. However, the material performance can be improved using tailored heat treatments. Careful consideration must be given to suitable post-processing before application in critical components in the aerospace or biomedical industry can occur.<hr/>LaserCUSING® is 'n selektiewe lasersmeltproses met die vermoë om onderdele te vervaardig deur die smelt van poeier met hitte inset van 'n laserstraal. LaserCUSING toon die potensiaal om ingewikkelde geometrieë benodig vir biomediese implantate en lugvaart toepassings, te produseer. Een van die hoof beperkings tot hierdie vorm van blits prototipering is die tekort aan gepubliseerde studies oor die materiaaleienskappe van die gevolglike materiaal. Studies van die materiaaleienskappe is dikwels verder gekompliseer as gevolg van die invloed van verskeie faktore, soos die aanvanklike poeier eienskappe, die laser parameters en hittebehandelings na die lasersmeltproses. Hierdie studie beoog om die meganiese eienskappe van Ti-6Al-4V wat met LaserCUSING geproduseer is, en die vertoning daarvan relatief tot 'n konvensionele bewerkte eweknie, te ondersoek. 'n Kombinasie van konvensionele en aangepaste hittebehandelings is toegepas. Die resulterende mikro-strukture is ondersoek en verwantskappe tot die resultate van hardheidstoetse is gevind. Die resultate toon dat die Ti-6Al-4V met tradisionele materiale kan kompeteer mits optimale parameters vooraf gekies word en dat onderdele aangepaste hittebehandelings ondergaan. Die Ti-6Al-4V toon beter sterkte en hardheid, maar het swakker smeebaarheid. Noukeurige oorweging vir verwerking na die lasersmelt is nodig voor die toepassing daarvan op kritiese komponente. <![CDATA[<b>The need for powder characterisation in the additive manufacturing industry and the establishment of a national facility</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S2224-78902015000200010&lng=pt&nrm=iso&tlng=pt The characteristics of powders used in additive manufacturing can have significant effects on process efficiencies and the quality of the final products. Powder sizes and morphologies need to be optimised for a particular process, and this requires the facilities to perform these measurements as well as provide a quality check on powder batches that are purchased. The establishment of a national powder characterisation facility has been identified by the Titanium Centre of Competence (a DST-funded initiative) as a critical form of support for the development of a South African titanium metal industry. This paper discusses what effect the different powder characteristics can have on the selective laser sintering processes, as well as the state of development of this national facility.<hr/>Die eienskappe van die poeiers wat gebruik word vir toevoegingsvervaardiging kan 'n noemenswaardige invloed op die prosesdoeltreffendheid en die gehalte van die finale produkte hê. Poeiergroottes en morfologieë moet geoptimeer word vir 'n spesifieke proses en dit vereis dat fasiliteite hierdie metings moet doen. Die gehalte van die poeier lotte moet ook verseker word. Die daarstelling van 'n nasionale poeier karakteriseringsfasiliteit is deur die Titaan Bevoegdheidsentrum identifiseer as 'n kritiese ondersteuningsmiddel vir die ontwikkeling van 'n Suid-Afrikaanse titaanmetaalindustrie. Hierdie artikel bespreek die effek van verskillende poeiereienskappe op die selektiewe lasersinterprosesse asook die ontwikkeling status van hierdie nasionale fasiliteit. <![CDATA[<b>Application of a system dynamics model to improve the performance of make-to-order production</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S2224-78902015000200011&lng=pt&nrm=iso&tlng=pt This study provides a system dynamics (SD) model of make-to-order (MTO) production and discusses the key factors of production improvement. The proposed system can be divided into three subsystems: income/cost, order/production, and human resources (HR). The time delay between customer demand, production demand, order quantity, material demand, and inventory is considered in a practical application. In addition, this paper considers how the cycle time is affected by the total input of HR; how unit transportation cost is influenced by the delivery quantity; and how unit penalty (shortage) cost is affected by the amount of shortage. The production capacity, yield, and holding cost needed to satisfy practical demands are all considered. A simulation approach to MTO production for meeting contract requests is presented in this study. Simulation results reveal that the amount of shortage will be the most important factor affecting the policy for the replenishment of material. Although the rise in production capacity leads to a reduced amount of shortage, it does not play a significant role. A sensitivity analysis of the replenishment of material policy is conducted to find out the best suggested policy. The SD model is also shown to quickly simulate changes in system behaviour, which allows an organisation enough time to respond to and conquer any unpredictable situation that might occur.<hr/>'n Stelseldinamika model van 'n vervaardig-op-bestelling proses word gestel en die sleutelfaktore vir proses verbetering word bespreek. Die voorgestelde sisteem kan in drie subsisteme verdeel word, naamlik inkomste/koste, bestelling/produksie en menslike hulpbronne. Die tydsverloop tussen die kliëntevereiste, produksievereiste, bestelling hoeveelheid, materiaalvereiste en voorraad word in 'n praktiese toepassing oorweeg. Verder word daar gekyk na hoe die siklustyd affekteer word deur die menslike hulpbron insette, hoe eenheidsvervoerkoste deur afleweringshoeveelheid beïnvloed word en hoe eenheidstekortkoste deur die hoeveelheid stoorspasie beïnvloed word. Die produksiekapasiteit, -opbrengs en bergkoste benodig om praktiese vereistes te bevredig word oorweeg. A simulasie gebaseerde benadering tot vervaardig-op-bestelling produksie word voorgehou. Die simulasie resultate toon dat die tekort die belangrikste faktor is wat die materiaalvervangingsbeleid beïnvloed. Alhoewel verhoogde produksiekapasiteit tot 'n verminderde tekort lei, speel dit nie 'n beduidende rol nie. 'n Sensitiwiteitsanalise van die materiaalvervangingsbeleid is gedoen om die beste beleid voor te stel. Die stelseldinamika model word ook gebruik om vinnig veranderinge in die stelselgedrag te simuleer - dit gee 'n organisasie genoeg tyd om op onvoorspelde situasies wat hulself voor doen te reageer en te oorkom. <![CDATA[<b>Quantifying system reliability in rail transportation in an ageing fleet environment</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S2224-78902015000200012&lng=pt&nrm=iso&tlng=pt In recent years the management of physical assets has become increasingly important, especially in asset-intensive organisations. This article presents an approach to quantifying the reliability of rolling stock assets in the rail environment, making use of failure statistics. Failure distributions and the interdependency of different systems are used to determine the impact of component failures on overall system reliability, and to determine the reliability of individual train sets. Recommendations about the future planning of maintenance are included in the article.<hr/>Die bestuur van fisiese bates het in die afgelope tyd al meer belangrik geword, veral in bate intensiewe organisasies. Hierdie artikel stel 'n metode voor wat die betroubaarheid van rollende materiaal bates in die spoor bedryf kwantifiseer deur gebruik te maak van falingstatistiek. Falingverspreidings en interafhanklikheid van stelsels word gebruik om te bepaal wat die invloed is van komponent falings op die betroubaarheid van die totale stelsel. Hierdie benadering word dan gebruik om die betroubaarheid van individuele treinstelle te bepaal. Aanbevelings word ook gemaak hoe om betroubaarheid te gebruik om die beplanning van instandhouding te doen. <![CDATA[<b>Comparing the performance of different meta-heuristics for unweighted parallel machine scheduling</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S2224-78902015000200013&lng=pt&nrm=iso&tlng=pt This article considers the due window scheduling problem to minimise the number of early and tardy jobs on identical parallel machines. This problem is known to be NP complete and thus finding an optimal solution is unlikely. Three meta-heuristics and their hybrids are proposed and extensive computational experiments are conducted. The purpose of this paper is to compare the performance of these meta-heuristics and their hybrids and to determine the best among them. Detailed comparative tests have also been conducted to analyse the different heuristics with the simulated annealing hybrid giving the best result.<hr/>Die minimering van vroeë en trae take op identiese parallelle masjien met behulp van die gepaste gleufskeduleringsprobleem word oorweeg. Die probleem is nie-deterministies polinomiese tyd volledig en die vind van 'n optimale oplossing is dus onwaarskynlik. Drie meta-heuristieke en hul hibriede word voorgestel en uitgebreide berekeningseksperimente word uitgevoer. Die doel van hierdie artikel is om die vertoning van hierdie meta-heuristieke en hul hibriede met mekaar te vergelyk om sodoende die beste te identifiseer. Gedetaileerde vergelykende toetse is ook uitgevoer om die verskillende heuristieke te ondersoek; daar is gevind dat die gesimuleerde uitgloei hibried die beste resultaat lewer. <![CDATA[<b>Multi-criteria decision-making methods for supplier selection: A literature review</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S2224-78902015000200014&lng=pt&nrm=iso&tlng=pt A firm's multi-criteria decision-making (MCDM) process is important because of its need to select and work with various suppliers. The process identifies the problems associated with selecting the supplier, , determining convenient criteria, expressing interactions clearly, and usage. These are all suitable methods for finding a solution to these MCDM problems. Considering more than one criterion (and even the sub-criteria of these criteria) during supplier selection makes the selection uncertain. Conventional methods cannot generate a realistic solution to the problem. Using MCDM methods considerably simplifies solving the problem, and enables decision-makers to make better decisions. In this study, a literature review was performed on MCDM methods used between 2001 and 2014 for the supplier selection problem. MCDM methods used in supplier selection are categorised into three main methods, and a summary table of the reviewed studies is presented.<hr/>'n Firma se multi-maatstaf besluitnemingsproses is belangrik as gevolg van die behoefte om verskeie verskaffers te kies en dan mee saam te werk. Die proses identifiseer die probleme geassosieer met die kies van die verskaffer, die bepaling van gerieflike kriteria, en wat die duidelike uitdruk van interaksies en die gebruik daarvan, insluit. Hierdie is almal gepaste metodes vir die vind van 'n oplossing tot hierdie multi-maatstaf besluitnemingsproses probleme. Die oorweging van meer as een maatstaf (en selfs die sub-maatstawwe van hierdie maatstaf) tydens verskaffer seleksie maak die seleksie onseker. Tradisionele metodes kan nie 'n realistiese oplossing tot die probleem genereer nie. Deur van multi-maatstaf besluit-nemingsprosesmetodes gerbuik te maak word die oplos van die probleem aansienlik vereenvoudig en dit stel besluitnemers in staat om die beter besluite te neem. 'n Literatuurstudie is gedoen op multi-maatstaf besluitnemingsprosesmetodes gebruik vir die verskaffer seleksie probleem van 2001 tot 2014. Die metodes word in drie afdelings verdeel en 'n opsommende tabel van die studies word voorgehou. <![CDATA[<b>A comparison of Phase I control charts</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S2224-78902015000200015&lng=pt&nrm=iso&tlng=pt A carefully done Phase I analysis is a vital part of an overall statistical process control and monitoring regime. Distribution-free control charts can play a useful role in this analysis, as a parametric model assumption often cannot be adequately verified. The performance of two distribution-free charts for the location - the mean-rank and the median chart - are compared in this paper. For benchmarking reasons, the parametric X-chart is included in the comparisons. It is seen that the distribution-free charts are in-control robust, whereas the X-chart is not, and they both perform similarly to the X-chart for normally distributed data. However, for non-normal data, they both outperform the X-chart. The results provide evidence in favour of using distribution-free Phase I charts in practice. Concluding remarks and suggestions for future research are given.<hr/>'n Versigtige analise van Fase I is 'n belangrike deel van 'n algehele statistiese proseskontrole en monitering skema. Verdelingsvrye kontrolekaarte kan 'n nuttige rol in hierdie fase speel, aangesien die model aannames nie voldoende geverifieer kan word nie. Die prestasie van twee verdelingsvrye kontrolekaarte - die gemiddelde-rank en die mediaan kontrolekaarte - word vergelyk in hierdie artikel. Vir vergelykingsredes, is die parametriese X-kontrolekaart ingeluit in die vergelykings. Dit is gevind dat die verdelingsvrye kontrolekaarte robuuste eienskappe het, terwyl die X-kontrolekaart dit nie het nie, en beide presteer op soortgelyke wyse as die X-kontrolekaart vir normaalverdeelde data. Egter, vir nie-normale data vaar albei beter as die X-kontrolekaart. Hierdie resultate bied bewyse ten gunste van die gebruik van verdelingsvrye Fase I kontrolekaarte in die praktyk. Slotopmerkings en voorstelle vir toekomstige navorsing word gegee. <![CDATA[<b>Evaluating the operational and environmental benefits of a smart roundabout</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S2224-78902015000200016&lng=pt&nrm=iso&tlng=pt Vehicle fuel consumption and emission rates in Kuwait have increased considerably over recent decades, and are now causing health and economic problems. A three-lane smart roundabout is a new and innovative design idea that can help to mitigate these issues. The smart roundabout was designed with a dedicated exit lane on the right side of each entryway, and a U-turn path connecting each adjacent entry and exit road. Both features permit vehicles to turn in specific directions without needing to enter the roundabout itself. Underground tunnels were designed for pedestrian and cyclist use. The objective of this study was to measure the impact of a smart roundabout on vehicle fuel consumption and on emissions of carbon dioxide, carbon monoxide, nitrogen oxides, and hydrocarbons. These results were then compared with those of a traditional roundabout and of a light-signalised intersection. Two light-signalised intersections with different traffic volumes were chosen for this study and simulated in their present state, as replaced by traditional roundabouts; and as replaced by smart roundabouts using the SIDRA 6.0 software. The smart roundabout allowed traffic to proceed with minimal delay and idling time, significantly reducing vehicle fuel consumption and emissions in comparison with a traditional roundabout or light-signalised intersection. Furthermore, the smart roundabout allowed pedestrians and cyclists to move safely through the intersection without interacting with vehicular traffic.<hr/>Voertuig brandstofverbruik en emissietempo's in Koeweit het aansienlik verhoog oor die laaste paar dekades en veroorsaak gesondheid- en ekonomiese probleme. A drie-laan slim verkeersirkel is 'n nuwe en innoverende ontwerp wat kan bydrae tot die verligting van hierdie kwessies. Die slim verkeersirkel is ontwerp met 'n toegewyde uitgangslaan aan die regterkant van elke ingang en 'n U-draai baan wat naburige ingang- en uitgangslane verbind. Beide kenmerke laat voertuie toe om in spesifieke rigtings te draai sonder om die verkeersirkel te betree. Ondergrondse tonnels is gebruik vir voetgangers en fietsryers. Die doel van die studie is om die impak van so 'n slim verkeersirkel op die brandstofverbruik en uitlaat van koolstofdioksied, koolstofmonoksied, stikstofoksiede en hidrokoolstowwe te meet. Die resultate is dan met dié van 'n tradisionele verkeersirkel en 'n verkeersligkruising vergelyk. Twee verkeersligkruisings met verskillende verkeervolumes is gekies vir hierdie studie en in hul huidige toestand, met tradisionele verkeersirkels en met die voorgestelde slim verkeersirkel, met behulp van die SIDRA 6.0 sagteware gesimuleer. Die slim verkeersirkel het die verkeer met minimale vertraging en luier tyd laat vloei wat die brandstofverbruik en uitlaatgasse noemenswaardig laat verminder het. Verder het die slim verkeersirkel voetgangers en fietsryers met veilige deurgang deur die kruising verskaf sonder om met die padverkeer te meng. <![CDATA[<b>Fuzzification of the 'TOWS' strategic concept: A case study of the Magneti Marelli branch in the Serbian automotive industry</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S2224-78902015000200017&lng=pt&nrm=iso&tlng=pt The purpose of this paper is to introduce a fuzzy approach to the quantification of the TOWS (Threats, Opportunities, Weaknesses, and Strengths) strategic concept (also known as 'SWOT'). Fuzzy logic and triangular fuzzy numbers are used to provide an alternate assessment of the internal strengths and weaknesses and external opportunities and threats in the process of developing strategic alternatives and making strategic choices. The developed fuzzy model is applied to a real-world case, conducted with the management team of the Magneti Marelli branch in Serbia, which operates as the largest supplier in the Serbian automotive industry. The results are discussed, and suggestions for further research are provided.<hr/>'n Wasige benadering tot die kwantifisering van die TOWS (bedregings, geleenthede, swakpunte en sterkpunte) strategiese konsep word bekendgestel. Wasigheidsleer en driehoekige wasige nommers is gebruik om 'n alternatiewe beoordeling van die interne sterk- en swakpunte en eksterne geleenthede en bedreigings in die strategiese alterna-tieweontwikkelingsproses en strategiesebesluitneming te verskaf. Die ontwikkelde wasige model is toegepas op 'n gevallestudie van die bestuurspan van die Magneti Marelli tak in Serwië. Dit is die grootste verskaffer in die Serwiese voertuigindustrie. Die resultate is bespreek en voorstelle vir verdere navorsing is verskaf.