Scielo RSS <![CDATA[South African Journal of Industrial Engineering]]> http://www.scielo.org.za/rss.php?pid=2224-789020160001&lang=pt vol. 27 num. 1 lang. pt <![CDATA[SciELO Logo]]> http://www.scielo.org.za/img/en/fbpelogp.gif http://www.scielo.org.za <![CDATA[<b>Guest Editorial</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S2224-78902016000100001&lng=pt&nrm=iso&tlng=pt <![CDATA[<b>The status and challenges of industrial engineering in South Africa</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S2224-78902016000100002&lng=pt&nrm=iso&tlng=pt The industrial engineering discipline in South Africa is examined by introducing the context of the discipline and by revisiting its history. The drivers influencing the context and future of industrial engineering in South Africa are also considered, and the discipline is analysed in terms of the following aspects: university qualifications, employment in industry sectors, race and gender profiles, use and competence in industry, and income profiles. The analysis is based on a recent survey sent to practising industrial engineers, on membership data from the Southern African Institute for Industrial Engineering (SAIIE), and on two internal SAIIE investigations. The study concludes that the success of transformation, particularly in terms of race, has been limited. The results also indicate that there are an almost equal number of black and white industrial engineers, yet the majority of black industrial engineers have technical qualifications, while the majority of white industrial engineers have academic qualifications. The results indicate that this limits the use of black industrial engineers in industry and, consequently, the success of their careers. This in turn means that there are fewer black role models to attract young black students to the discipline. Some preliminary opportunities to unlock the increased transformation of the profession are identified.<hr/>Die bedryfsingenieurswese dissipline in Suid-Afrika is ondersoek deur eerstens die konteks van die dissipline te stel, die geskiedenis op te som, die drywers te identifiseer wat die konteks en toekoms van bedryfsingenieurswese beïnvloed, en dan die dissipline te analiseer in terme van die volgende aspekte: universiteit kwalifikasies, indiensneming in industrie sektore, ras en geslag profiele, benutting en vaardigheid in industrie, en inkomste profiele. Die analise is gebaseer op 'n onlangse meningsopname wat aan praktiserende bedryfsingenieurs gestuur is, op die Suider Afrikaanse Instituut van Bedryfsingenieurswese (SAIIE) se lidmaatskap data, en op twee interne SAIIE ondersoeke wat gedoen is. Die studie bevind dat die sukses van transformasie, veral in terme van ras, nog beperk is. Die resultate toon dat daar omtrent ewe veel wit en swart bedryfsingenieurs is, maar dat die meerderheid swart bedryfsingenieurs tegniese kwalifikasies het, terwyl die meerderheid wit bedryfsingenieurs akademiese kwalifikasies het. Die resultate toon dat dit die benutting van swart bedryfsingenieurs in industrie beperk en dus ook die sukses wat hul in hul loopbane behaal in terme van inkomste. Dit veroorsaak dat daar minder swart rolmodelle is om jong swart student na die dissipline te lok. Voorlopige geleenthede om transformasie in die professie te ontsluit word geïdentifiseer. <![CDATA[<b>Exact run length distribution of the double sampling<i><img border=0 width=32 height=32 src="../../../../img/revistas/sajie/v27n1/03ii2.jpg"></i>chart with estimated process parameters</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S2224-78902016000100003&lng=pt&nrm=iso&tlng=pt Since the run length distribution is generally highly skewed, a significant concern about focusing too much on the average run length (ARL) criterion is that we may miss some crucial information about a control chart's performance. Thus it is important to investigate the entire run length distribution of a control chart for an in-depth understanding before implementing the chart in process monitoring. In this paper, the percentiles of the run length distribution for the double sampling (DS) <img border=0 width=32 height=32 src="../../../../img/revistas/sajie/v27n1/03ii2.jpg"> chart with estimated process parameters are computed. Knowledge of the percentiles of the run length distribution provides a more comprehensive understanding of the expected behaviour of the run length. This additional information includes the early false alarm, the skewness of the run length distribution, and the median run length (MRL). A comparison of the run length distribution between the optimal ARL-based and MRL-based DS <img border=0 width=32 height=32 src="../../../../img/revistas/sajie/v27n1/03ii2.jpg"> chart with estimated process parameters is presented in this paper. Examples of applications are given to aid practitioners to select the best design scheme of the DS <img border=0 width=32 height=32 src="../../../../img/revistas/sajie/v27n1/03ii2.jpg"> chart with estimated process parameters, based on their specific purpose.<hr/>Aangesien die lopielengte verdeling in die algemeen baie skeef is, bestaan daar kommer oor die gebruik van die gemiddelde lopielengte (ARL) kriteria, omdat kritiese informasie op die beheerkaart gemis mag word. Dit is dus belangrik om die totale lopielengte verdeling van 'n beheerkaart te ondersoek, voordat die kaart geïmplementeer word. In hierdie artikel word die persentiele van die lopielengte verdeling van die dubbelmonster (DS) <img border=0 width=32 height=32 src="../../../../img/revistas/sajie/v27n1/03ii2.jpg"> kaart met geskatte prosesparameters bereken. Kennis van die persentiele van die lopielengte verdeling gee 'n meer omvattende verstaan van die verwagte lopielengte vertoning. Dié addisionele informasie sluit die vroeë vals alarm, die skeefheid van die verdeling en die mediaan van die lopielengte (MRL) in. 'n Vergelyking van die lopielengte verdeling tussen optimale ARL-gebaseerde en MRL-gebaseerde DS <img border=0 width=32 height=32 src="../../../../img/revistas/sajie/v27n1/03ii2.jpg"> kaart met geskatte proses parameters word voorgehou. Voorbeelde word ook voorgehou om beoefenaars te help om die beste weergawe van die DS <img border=0 width=32 height=32 src="../../../../img/revistas/sajie/v27n1/03ii2.jpg"> kaart met geskatte proses parameters vir hul toepassing te kies. <![CDATA[<b>The design and implementation of a garbage truck fleet management system</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S2224-78902016000100004&lng=pt&nrm=iso&tlng=pt In recent years, the improvement of cloud computing and mobile computing techniques has led to the availability of a variety of mobile applications ('apps') in the app store. For instance, a garbage truck app that can provide the immediate location of a garbage truck, the location of collection points, and forecasted arrival times of garbage trucks would be useful for mobile users. Since the power consumption of apps on mobile devices if of concern to mobile users, an optimised power-saving mechanism for updating messages, which is based on location information, for a proposed garbage truck fleet management system (GTFMS) is proposed and implemented in this paper. The GTFMS is a three-component system that includes the on-board units on garbage trucks, a fleet management system, and a garbage truck app. In this study, an arrival time forecasting method is designed and implemented in the fleet management system, so that the garbage truck app can retrieve the forecasted arrival time via web services. A message updating event is then triggered that reports the location of garbage truck and the forecasted arrival time. In experiments conducted on case studies, the results showed that the mean accuracy of predicted arrival time by the proposed method is about 81.45 per cent. As for power consumption, the cost of traditional mobile apps is 2,880 times that of the mechanism proposed in this study. Consequently, the GTFMS can provide the precise forecasted arrival time of garbage trucks to mobile users, while consuming less power.<hr/>Die verbetering van wolkverwerking en mobiele verwerkings-tegnieke het gelei tot die beskikbaarheid van 'n groot verskeidenheid mobiele toepassings. 'n Voorbeeld hiervan is 'n toepassing wat die onmiddellike ligging van 'n vullistrok, die ligging van vullis versamelpunte en die voorspelde aankomstye van die vullistrokke aan die gebruiker verskaf. Die energieverbruik van die toepassings is ook van belang en 'n geoptimeerde energie-besparingsmeganisme vir die opdateer van boodskappe (wat inligting rakende die vullistrok se ligging bevat) word in hierdie artikel ontwerp en geïmplementeer. 'n Opdateringsboodskap rapporteer die vullistrok se ligging en voorspelde aankomstyd. Gevallestudies toon dat die gemiddelde akkuraatheid van die voorspelde aankomstyd 81.45% is. Die energieverbruik van die toepassing is 2880 keer minder as dié van 'n tradisionele mobiele toepassing. Gevolglik kan die voorgestelde vullistrokvlootbestuur-stelsel 'n baie akkurate aankomstyd voorspelling aan gebruikers gee terwyl dit min energie verbuik. <![CDATA[<b>Improving forecasts for better decision-making</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S2224-78902016000100005&lng=pt&nrm=iso&tlng=pt Improving the forecasting process may enable managers to make better decisions. In this paper, the forecasting process includes three factors: [A] forecasting input factors, [B] competitive advantage factors, and [C] forecasting effectiveness factors. It is proposed that a deeper understanding of the links between [A], [B] and [C] will lead to improvements in forecasting and better decision-making. The objective of this paper is to develop a model that will allow managers to improve forecasting by better understanding the links in the model. Structural equation modelling (SEM) is used to test the model. Twenty-two hypotheses are tested, of which 18 are accepted.<hr/>Die verbetering van die voorspellingsproses mag bestuurders daartoe in staat stel om beter besluite te neem. Die voorspellingsproses wat in hierdie artikel bespreek word sluit drie faktore in, naamlik [A] voorspellingsinsetfaktore, [B] mededing-endevoordeelfaktore en [C] voorspellingseffektiwiteitsfaktore. Dit word voorgestel dat 'n dieper verstaan van die skakels tussen [A], [B] en [C] tot verbeteringe in voorspel en beter besluitneming sal lei. Die doel van dié artikel is om 'n model, wat bestuurders sal toelaat om voorspelling te verbeter deur die skakel in die model, te ontwikkel. Strukturele vergelykingmodellering word gebruik om die model te toets. Twee-en-twintig hipoteses word getoets, waarvan daar agtien aanvaar word. <![CDATA[<b>Alignment of internal and external business and innovation domains</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S2224-78902016000100006&lng=pt&nrm=iso&tlng=pt "Instead of being really good at doing some particular thing, companies must be really good at learning how to do new things" [1]. This ability to do new things involves both the identification and the mastery of the next 'new thing' as well as the ability to align the rest of the company with this new direction. This paper focuses on the alignment of innovation activities with the overall business strategy and infrastructure. An innovation strategic alignment model is presented that supports alignment in a company by identifying the driver of change and its impact on other areas of the business.<hr/>"Instead of being really good at doing some particular thing, companies must be really good at learning how to do new things" [1]. Die vermoë om iets nuut te doen berus op beide die identifisering en bemeestering van die nuutheid, sowel as die belyning van die bestaande maatskappy met hierdie nuwe wending. Hierdie artikel belig die belyning van innovasie aktiwiteite binne die onderneming met die algemene besigheidstrategie asook infrastruktuur. 'n Innovasiestrategie belyningsmodel word voorgestel. Hierdie model ondersteun belyning deur identifisering van die drywer van verandering en die impak daarvan op ander besigheidsareas. <![CDATA[<b>Resource-efficient process chains to manufacture patient-specific prosthetic fingers</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S2224-78902016000100007&lng=pt&nrm=iso&tlng=pt The high cost of quality prostheses, together with the lack of trained prosthetists, makes it challenging to obtain prosthetic devices in developing communities. Modern 3D digitising techniques and additive manufacturing (AM) technologies are gaining popularity in the bio-medical industry and, in the case of prosthesis production, reduce the need for a trained prosthetist. The objective of this research was to develop a new resource-efficient process chain for the manufacturing of prosthetic fingers using additive manufacturing technologies, and to compare it with the traditional (Sculptor) process chain. Fused deposition modelling (FDM), open-source FDM, 3-dimensional printing (3DP), and stereolithography (SLA) were evaluated in terms of their costs, time, material usage, and aesthetic quality. The surface qualities produced with the different additive manufacturing technologies were also compared. The results showed that 3DP was the preferred technology and was the best candidate for the production of prosthesis in terms of cost, quality, and time for developing communities. SLA produced the highest aesthetic quality prosthesis, but was the most expensive. It was concluded that using the additive manufacturing technology process chain to produce prosthetic fingers is faster and more cost effective than the traditional method.<hr/>Die hoë kostes van gehalte prosteses, en die toegang tot opgeleide prostese vervaardigers, maak dit 'n uitdaging om prostetiese toestelle in ontwikkelende gemeenskappe te bekom. Moderne 3D digitaliserings tegnieke en toevoeging vervaardiging (AM) tegnologie is besig om in die bio-mediese bedryf gewild te raak en, in die geval van prostese produksie, kan dit die behoefte aan 'n opgeleide prostese vervaardigers beperk. Die doel van hierdie navorsing was om 'n nuwe hulpbron doeltreffende proses ketting vir die vervaardiging van prostetiese vingers met behulp toevoeging vervaardiging tegnologie te ontwikkel en om dit te vergelyk met die tradisionele proses ketting. Saamgesmelte afsetting modellering (FDM), 3-dimensionele druk (3DP) en stereolithography (SLA) is geëvalueer in terme van hul kostes, tyd, materiaal verbruik en estetiese gehalte. Die geproduseerde oppervlak eienskappe van die verskillende toevoeging vervaardiging tegnologieë is ook vergelyk. Die resultate het getoon dat 3DP die voorkeur-tegnologie en die beste kandidaat vir die produksie van prostese in terme van koste, kwaliteit en tyd vir die ontwikkeling van gemeenskappe was. SLA het die hoogste estetiese gehalte prostese vervaardig, maar was die duurste. Die gebruik van AM tegnologie binne die waardeketting om prostetiese vingers te produseer, is vinniger en meer koste-effektiewe as die tradisionele metode. <![CDATA[<b>Linking culture, organizational learning orientation and product innovation performnace: The case of Ethiopian manufacturing firms</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S2224-78902016000100008&lng=pt&nrm=iso&tlng=pt Using formal survey data from textile and leather product manufacturing firms in Ethiopia, we investigate how the current national cultural setup (power distance, collectivism, masculinity and uncertainty avoidance) is affecting organizational learning, orientation and product innovation performance. Further, we assess the moderating role of sector and ownership structure on the interrelationship. The result demonstrates that the current national culture setup is negatively affecting the learning and innovation activities of the firms in the country. It also shows that while sector type is neutral, ownership type significantly affects the interrelationship among culture, learning orientation and product innovation performance.<hr/>Deur die gebruik van peilingdata van tekstiel- en leerproduk vervaardigers in Etiopië word die invloed van die huidige nasionale kulturele milieu (dit sluit die afstand tot krag, kollektivisme, manlikheid en onsekerheidsvermyding) op die organisatoriese leer, oriëntasie en produkinnovasie bestudeer. Verder word die matigende rol van sektortipe en eienaarskapstruktuur op die onderlinge verhoudinge beoordeel. Die resultaat toon dat die huidige nasionale kulturele milieu die leer- en innovasieaktiwiteite negatief beïnvloed. Dit toon ook dat, terwyl die sektortipe nie 'n noemenswaardige invloed het nie, die eienaarskapstruktuur die onderlinge verhouding tussen kultuur, leeroriëntasie en produkinnovasie daadwerklik beïnvloed. <![CDATA[<b>Deriving a research agenda for a financial service industry's methodology for carrying out business process re-engineering</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S2224-78902016000100009&lng=pt&nrm=iso&tlng=pt Why do projects fail? This is a question that has been researched across various project disciplines, including that of Business Process Re-engineering (BPR). This paper introduces a different angle on why BPR projects fail. An analysis of a case study conducted within a financial institution revealed new factors that could influence BPR project outcomes, but that have not been identified in the literature. The Organisation Ring of Influence model was developed to indicate the impact that organisation behaviours and structures had on the outcome of an executed BPR project. This model also helps to highlight which factors were more influential than others.<hr/>Waarom misluk projekte? Dit is 'n vraag wat oor verskeie projek-dissiplines nagevors is, insluitende dié van besigheidsproses-herontwerp. Hierdie artikel stel 'n nuwe hoek bekend om die oorsaak vir projekmislukking te bepaal. 'n Analise van 'n gevallestudie, wat by 'n finansiële instansie geloods is, het nuwe faktore wat die besigheidsprosesherontwerp beïnvloed, onthul. Hierdie faktore is nie in bestaande navorsing geïdentifiseer nie. Die Organisasie-Ring-van-Invloed model is ontwikkel om die impak wat die organisatoriesegedrag en -strukture op die eindresultaat van 'n voltooide besigheidsprosesherontwerp projek gehad het, aan te dui. Die model help ook om die faktore wat meer invloed uitoefen uit te lig. <![CDATA[<b>Artificial intelligence applied to assigned merchandise location in retail sales systems</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S2224-78902016000100010&lng=pt&nrm=iso&tlng=pt This paper presents an option for improving the process of assigning storage locations for merchandise in a warehouse. A disadvantage of policies in the literature is that the merchandise is assigned allocation only according to the volume of sales and the rotation it presents. However, in some cases it is necessary to deal with other aspects such as family group membership, the physical characteristics of the products, and their sales pattern to design an integral policy. This paper presents an alternative to the aforementioned process using Flexsim®, artificial neural networks, and genetic algorithms.<hr/>'n Metode om die toekenningsproses van stoorplekke vir goedere in 'n pakhuis te verbeter, word voorgehou. 'n Nadeel van die bestaande beleide in die literatuur is dat die goedere slegs toegeken word op grond van die verkoopvolume en die omset wat dit verteenwoordig. In sommige gevalle is dit egter nodig om ander aspekte, soos familie groeplidmaatskap, die fisiese eienskappe van die produkte en hulle verkoopspatroon, te oorweeg om 'n integrale beleid te formuleer. Hierdie artikel beskryf 'n alternatief vir die voorafgenoemde proses deur van Flexsim®, kunstmatige neurale netwerke en genetiese algoritmes gerbuik te maak. <![CDATA[<b>The impact of innovation strategy on organizational learning and innovation performance: Do firm size and ownership type make a difference?</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S2224-78902016000100011&lng=pt&nrm=iso&tlng=pt Though innovation strategy and organizational learning have been credited to impact on product innovation performance, they have been rarely considered in a single model simultaneously. Thus, the main aim of the paper is to investigate the extent of impact of innovation strategy on organizational learning and product innovation performance. A structural equation modelling analysis was performed on the survey data collected from Ethiopian textile and leather product manufacturing firms. The result reveals that innovation strategy is positively related to product innovation performance. Further, firm size and ownership type moderate the effect of innovation strategy on product innovation performance.<hr/>Alhoewel daar erken word dat innovasiestrategie en organisatoriese-leer produkinnovasievertoning beïnvloed, word dit selde gelyktydig in 'n enkele model oorweeg. Die doel van die artikel is dus om die invloedsbereik van innovasiestrategie op organisatoriese-leer en produkinnovasievertoning te ondersoek. 'n Strukturelevergelykingsmodellering analise is op opname data van 'n Etiopiese tekstiel- en leerproduk vervaardigers gedoen. Die resultaat toon dat innovasiestrategie positief verwant is aan produkinnovasiesvertoning. Verder is daar gevind dat maatskappy grootte en eienaarskaptipe die invloed van innovasiestrategie op produkinnovasievertoning matig. <![CDATA[<b>The absence of a creative focus in the conventional engineering design process: Identifying research opportunities to address this</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S2224-78902016000100012&lng=pt&nrm=iso&tlng=pt This paper synthesises an overview of various models of the engineering design process with an overview of the most relevant theories within the field of creativity studies to conclude that (i) creativity plays a role throughout the engineering design process, and it is possible to incorporate creativity into the engineering design process in a systematic manner; (ii) doing so, at the very least, holds significant potential for economic benefit; and (iii) due to the complex interplay between creativity and the wide range of factors that influence it, organisational climates and management practices cannot simply be assumed to support creativity effectively. It is proposed that organisations be managed proactively to support creativity in engineering design. For this study, a structured literature search protocol was implemented to determine whether there is any evidence in the literature that engineering organisations are being managed proactively with this in mind; none was found. Two opportunities for future research are suggested based on these findings: (i) the development of a framework to guide the proactive management of engineering organisations to support creativity; and (ii) the development of mechanisms for measuring creativity in engineering organisations and engineering design.<hr/>Hierdie navorsing kombineer 'n oorsig van die verskillende modelle van die ingenieursontwerp-proses met 'n oorsig van die mees relevante teorieë binne die veld van kreatiwiteitstudies en kom tot die gevolgtrekking dat (i) kreatiwiteit deur die volledige gang van die ingenieursontwerp-proses 'n rol speel, en dit moontlik is om kreatiwiteit op 'n sistematiese wyse in die ingenieursontwerp-proses in te lyf; (ii) so 'n benadering minstens die potensiaal vir beduidende ekonomiese voordeel inhou; en (iii) weens die komplekse interaksie tussen kreatiwiteit en die breë stel faktore wat dit beïnvloed, dit onakkuraat is om aan te neem dat organisasies se klimate en bestuurspraktyke noodwendig kreatiwiteit ondersteun. Daar word voorgestel dat organisasies proaktief bestuur behoort te word om kreatiwiteit in ingenieursontwerp te ondersteun. 'n Gestruktureerde protokol word gevolg om vas te stel of daar in die literatuur bewyse is dat ingenieursorganisasies tans so proaktief bestuur word. Geen bewyse word gevind nie. Twee geleenthede vir verdere navorsing word na gelang van hierdie bevindinge voorgestel: (i) die ontwerp van 'n raamwerk om riglyne te bied vir die proaktiewe bestuur van ingenieursorganisasies om kre'atiwiteit te ondersteun; en (ii) die ontwikkeling van meganismes om kreatiwiteit in ingenieursorganisasies en in ingenieursontwerp te meet. <![CDATA[<b>The effect of a Project Management Office on project and organisational performance: A case study</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S2224-78902016000100013&lng=pt&nrm=iso&tlng=pt Depending on the specific needs of the host companies, Project Management Offices (PMOs) are created and mandated for different reasons. As a result of varying mandates and functions of PMOs, there is no agreed method to determine the value of a PMO. By studying the case of an organisation that recently implemented a PMO, this paper provides some insight into ways to determine the value of a PMO. Three new methods for determining the value of a PMO are proposed.<hr/>Projekbestuurkantore (PKe) word geskep en ontvang mandate vir verskillende redes wat bepaal word deur die spesifieke behoeftes van die gasheer maatskappy. As gevolg van die verskille in mandate en funksies van PKe, bestaan daar tans geen algemeen aanvaarde metode om die waarde van 'n PM te bepaal nie. Deur die studie van 'n geval van 'n- organisasie wat onlangs 'n PK geïmplementeer het, bied hierdie artikel insig oor maniere waarop die waarde van 'n PK bepaal kan word. Drie nuwe metodes vir bepaling van die waarde van 'n PK word voorgestel. <![CDATA[<b>A fuzzy approach to selecting roof supports in longwall mining</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S2224-78902016000100014&lng=pt&nrm=iso&tlng=pt As a decision-making problem, selecting proper machines and equipment plays a key role for mining sites and companies. Many factors affect this decision, and values belonging to these factors can be expressed numerically and/or non-numerically. In order to make the most appropriate decision, engineers must carry out an evaluation process that comprises all criteria that might affect decision-making. To achieve this, multi-criteria decision-making tools are used. As a result of technological developments, coal outputs in longwall mining have risen tremendously over the last decades, and longwall mechanisation has become unavoidable. The significance of powered roof supports in particular increases day-by-day, since the rate of roof support has to be in accordance with the rate of face advance in longwalls. In this study, an integrated fuzzy analytic hierarchy process and fuzzy goal programming model is used to select the most suitable powered roof supports. The procedure is applied to a real-life underground coal mine that is operated using the longwall method. Seven alternative powered roof supports are compared with each other, taking a total of 24 decision criteria under four main topics into account. In conclusion, the most suitable roof supports for the mine under study are determined and recommended to the decision-makers of the system.<hr/>'n Die selekteer van die regte masjinerie en toerusting speel 'n sleutelrol vir myn werwe en mynmaatskappye. Daar is baie faktore wat dié besluit beïnvloed en numeriese of nie-numeriese waardes kan aan hierdie faktore toegeken word. Om die regte besluit te neem, moet ingenieurs al die kriteria wat die besluit mag beïnvloed oorweeg. Hiervoor word multi-kriteria besluitneming-strategieë gebruik. As gevolg van tegnologiese ontwikkelinge, het die steenkoolontginning van ondergrondse myne drasties toege-neem en is meganisering van dié myne onvermeidelik. Die belang van aangedrewe plafonstutte het veral toegeneem as gevolg van die vinnige tempo van skag verlenging. 'n Wasige analitiese hiërargieproses en wasige doelbeplannings-model word gebruik om die gepaste aangedrewe plafonstutte te kies. Die prosedure word toegepas op 'n ondergrondse steenkool-myn. Sewe aangedrewe plafonstutte word met mekaar vergelyk; die vergelyking neem 24 besluitnemingskriteria, wat onder vier hoofafdelings verdeel is, in ag. Gevolglik word die mees geskikte plafonstut gekies en aanbeveel. <![CDATA[<b>Reduction of production cycle time by optimising production and non-production components of time in the metalworking industry: A case study</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S2224-78902016000100015&lng=pt&nrm=iso&tlng=pt The production cycle (PC) time, as a very important economic indicator of freezing current assets, involves the time needed to manufacture a unit or a series of units, from putting them into production until they are put into storage; and yet it is rarely discussed in the literature, even though it should be also analysed and be made as short as possible. The goal of this article is to survey and control the methodology of reducing the PC time of components in the metalworking industry, grouped by factor analysis into the factors of production and non-production components, observed by a modified method of current observations, and viewed as a process whose effectiveness was monitored using control charts. The survey is based on data collected through 1,576 observations in a Serbian company that manufactures electrical and electronic equipment for motor vehicles. The 2012 results, when compared with those of 2011, indicate that the PC time is significantly reduced by 93 minutes, or by 28.53 per cent, and the manufacturing time by 46 minutes, or by 19.17 per cent. The results furnish empirical findings that provide insights into a number of managerial issues concerning investment decisions in product-specific cycle time improvements and reductions, together with process redesigns.<hr/>Die produksiesiklustyd, 'n baie belangrike ekonomiese aanwyser vir die vries van bestaande bates, behels die tyd benodig om 'n eenheid (of 'n reeks eenhede) te vervaardig, van die begin van produksie tot die stoor van die eenheid. Tog word die produksie-siklustyd selde in die literatuur bespreek. Hierdie artikel ondersoek die opname- en beheermetode van die produksiesiklustyd van komponente in die metaalwerkindustrie, met die doel om dit te verkort. Komponente word gegroepeer deur middel van faktor-ontleding in produksie en nie-produksie komponente, dit word waargeneem deur 'n aangepaste huidige waarnemingsmetode, en hanteer as 'n proses waarvan die effektiwiteit met beheerkaarte gemonitor is. Die opname is gebaseer op 1576 waarnemings by 'n Serwiese vervaardiger van elektriese en elektroniese voertuig-onderdele. Die 2012 resultate, wanneer dit met dié van 2011 vergelyk word, dui aan dat die produksiesiklustyd met 93 minute, of te wel 28.53 persent, verminder het. Die vervaardigingstyd is met 46 minute, dit is 19.17 persent, verkort. Die resultate toon empiriese bevindings wat insig in etlike bestuurskwessies, rakende beleggingsbesluite in produkspesifieke siklustyd verbeteringe en prosesherontwerpe, gee. <![CDATA[<b>The use of Earned Value Management for initiating directive project control decisions: A case study</b>]]> http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S2224-78902016000100016&lng=pt&nrm=iso&tlng=pt With large infrastructure backlogs in Africa, well-controlled projects will play a significant role in African infrastructure development. In this paper, the monitoring and/or directive use of Earned Value Management (EVM) is investigated and linked to project management maturity. This case study also investigates the use of EVM based on the financial and schedule risk distribution among project role players, and the effect of EVM on project performance. The results show minimal use of EVM in the directive control of projects; at best, the directive use of EVM is found to be implied rather than deliberate and methodical.<hr/>Met groot agterstande in infrastruktuur in Afrika kan goed-beheerde projekte 'n beduidende rol in die ontwikkeling van infrastruktuur speel. In hierdie artikel word die monitering en direktiewe gebruik van verdiende-waarde bestuur (VWB) ondersoek en gekoppel aan projekbestuur volwassenheid. Die gebruik van VWB op projek prestasie is ook ondersoek aan die hand van 'n geval. Die resultate toon minimale gebruik van VWB in die direktiewe beheer van projekte; die direktiewe gebruik van VWB is hoogstens implisiet eerder as feitelik.