ORiON https://orion.journals.ac.za/pub <p><strong>Aims &amp; scope</strong><br>ORiON is the official journal of the Operations Research Society of South Africa (ORSSA) and is published biannually. Papers in the following categories are typically published in ORiON:<br><em>&nbsp;- Development of New Theory</em>, which may be useful to operations research practitioners, or which may lead to the introduction of new methodologies or techniques.<br><em>&nbsp;- OR Success Stories</em>, which describe demonstrably successful applications of operations research within the Southern African context (at the developing/developed economy interface) or similar environments elsewhere.<br><em>&nbsp;- OR Case Studies</em>, which might not be "success stories", but which emphasize novel approaches or describe pitfalls in the application of operations research.<br><em>&nbsp;- OR Methodological Reviews</em>, which survey new and potentially useful methodological developments, aimed at operations research practitioners especially in Southern Africa.</p> <p>The above list is by no means exhaustive.</p> en-US <p>The following license applies:</p><p><strong> Attribution CC BY</strong></p><p>This <a href="https://creativecommons.org/licenses/by/4.0/" target="_blank">license</a> lets others distribute, remix, tweak, and build upon your work, even commercially, as long as they credit you for the original creation.</p> jaco.visagie@nwu.ac.za (Jaco Visagie) orionmanager@orssa.org.za (Elzanie Bothma) Tue, 21 Dec 2021 14:32:52 +0000 OJS 3.1.2.4 http://blogs.law.harvard.edu/tech/rss 60 Editorial to Volume 37(2) https://orion.journals.ac.za/pub/article/view/709 Jaco Visagie Copyright (c) 2021 ORiON https://orion.journals.ac.za/pub/article/view/709 Tue, 21 Dec 2021 00:00:00 +0000 Content and Access Provision in a Discrete Competition Model https://orion.journals.ac.za/pub/article/view/704 <p>The non-rival, non-excludable and infinitely expansible characteristics of digital goods with marginal cost of zero strongly favours the use of bundling strategies. Theoretical tractability requires most models in the current literature to make highly stylized assumptions, rarely observed or anticipated in the real-life situations, motivating inquiry. This paper considers a competition model in which:</p> <p>* the firms, consumers and differentiated products are finite in number;</p> <p>* prices are discrete and not continuous;</p> <p>* consumers may purchase multiple items in a single product category where the degree of complementarity or substitutability of the product categories can also vary across consumers; and</p> <p>* where consumer-specific cost savings are obtained when purchasing multiple items from the same firm.</p> <p>Approximate solutions are obtained through numerical simulation. Firms act in concert to maximise the total firm revenue. Our main finding is that the interplay between maximal firm revenue, consumer surplus and prices is very complex and that high firm revenue and high consumer surplus are not antithetic. It suggests also that consumer surplus and market concentration are not necessarily related. Many market outcomes that are observed may be due to chance rather than design as diverse outcomes can accompany situations that are, to the firms, difficult to distinguish.</p> Petrus Potgieter, Bronwyn Howell Copyright (c) 2021 ORiON https://orion.journals.ac.za/pub/article/view/704 Tue, 21 Dec 2021 00:00:00 +0000 Energy Analysis via Value Stream Mapping https://orion.journals.ac.za/pub/article/view/688 <p>Over the past few decades, Lean Manufacturing (LM) has been the pinnacle of strategies applied for cost and waste reduction. However as the search for competitive advantage and production growth continues, there is a growing consciousness towards environmental preservation. With this consideration in mind this research investigates and applies Value Stream Mapping (VSM) techniques to aid in reducing environmental impacts of manufacturing companies. The research is based on empirical observation within the Chassis weld plant of Company X. The observation focuses on the weld operations and utilizes the cross member line of Auxiliary Cross as a point of study. Using various measuring instruments to capture the emissions emitted by the weld and service equipment, data is collected. The data is thereafter visualised via an Environmental Value Stream Map (EVSM) using a 7-step method. It was found that the total lead-time to build an Auxiliary Cross equates to 16.70 minutes and during this process &nbsp;is emitted. It was additionally found that the UPR x LWR stage of the process indicated both the highest cycle time and carbon emissions emitted and provides a starting point for investigation on emission reduction activity. The EVSM aids in the development of a method that allows quick and comprehensive analysis of energy and material flows. The results of this research are important to practitioners and academics as it provides an extension and further capability of Lean Manufacturing tools. Additionally, the EVSM provides a gateway into realising environmental benefits and sustainable manufacturing through Lean Manufacturing.</p> Keshav Ramsunder, Oludolapo Olanrewaju Copyright (c) 2021 ORiON https://orion.journals.ac.za/pub/article/view/688 Tue, 21 Dec 2021 00:00:00 +0000