Research Articles (Industrial and Systems Engineering)

Permanent URI for this collectionhttp://hdl.handle.net/2263/2374

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Now showing 1 - 20 of 261

Modelling, analysis and sensory metrication towards a quantitative understanding of complexity in systems
(MDPI, 2024-11) Ball, Melissa Claire; Ayomoh, Michael Kweneojo; u18015914@tuks.co.za
Modelling and metrication of the complexity of systems have occupied a growing and largely underdeveloped problem space in the literature of complex systems. In this research, preliminary results depicting the complexity of a service system premised on a tertiary institution of learning is presented. The concept deployed focused on modelling the trio core entities viz: functional elements, physical elements and the intricacy of connectivity associated with the flow of signals in the normal systemic operations. The numerous activities depicting diversity and multiplicity were holistically enumerated prior to sensing and metrication. The outcome of this research underscores effectiveness in the proposed model.
Revisiting shift cipher technique for amplified data security
(Bon View Publishing, 2024-02) Verma, Raksha; Kumari, Anjali; Anand, Adarsh; Yadavalli, Venkata S. Sarma
Ever sincemanualwork is overtaken by technology, the rapid advancement in the technologies for performing all kinds ofwork online has created newpossibilities for the organizations and institutions of all types.But this has also created opportunities for attackers and opponents by reducing the powers of existing controls over data sharing. All private, public, and any other sectors are using the internet for sharing their data. Transmission of unencrypted data over the internet is not secure as it posesmany privacy concerns as they can be easily hacked andmisused by any unintended person. So, everyone is concerned about safe and secure ways of data transmission in order to avoid leak of private data, as hackers always try tochase the transmitted data and torecover it, and thereforevarious different techniques are developed inorder tomake data transmission more secure. Encryption is essential to protect and prevent such lapses in the transmission of sensitive information over the internet and any other networks. In this paper, the author has worked on a better version of Caesar cipher and invented a method in which modular arithmetic is used to convert plaintext into ciphertext in order to amplify and to bolster up the security of the sensitive data or information, and the author composed the decryption method in such a way that it is no way related to encryption by involving the divisibility tests and arithmetic modulo.
Optimisation strategies and technological advancements for sustainable direct reduction iron production—a systematic review
(MDPI, 2025-03) Nyakudya Ncube, Ratidzo Yvonne; Ayomoh, Michael Kweneojo; u21837440@tuks.co.za
This systematic review examines optimisation strategies and technological advancements to foster sustainable direct reduction iron (DRI) production. The evaluation encompassed a meticulous review of journal articles, industrial reports, and conference papers published between 2002 and 2025, ultimately identifying 65 pertinent studies. A qualitative thematic analysis of the optimisation strategies enabled the identification of three primary themes: life cycle assessment strategies, modelling tools, and technological innovation strategies. This review highlights innovative approaches to using alternative reductants such as biomass and hydrogen, incorporating renewable energy sources in the process, and the economic feasibility of adopting these optimisation strategies. The research findings indicated that there is an urgent need to enhance waste management strategies, especially for coal-based reduction processes, as they are linked to environmental issues. Hydrogen-based reduction has been identified as an innovative methodology for waste control with the potential to reduce carbon dioxide emissions by up to 90%, though it has its limitations. The Circular Economy approach has been proposed as a viable strategy to reduce waste generation and extend the lifespan of materials used in the DRI process. This review provides essential insights on resource optimisation and utilisation and promotes technological innovation to improve the sustainability of DRI.
A systematic review of asset integrity and process safety management sustainability for onshore petrochemical installations
(MDPI, 2025-01) Ayomoh, Michael Kweneojo; Ongwae, Benard; u25477618@tuks.co.za
This paper presents a systematic review of the contributions of asset integrity and process safety management for the safe operations and sustainability of onshore petrochemical installations. The review highlights how the two systems work as prerequisites for minimizing industrial accidents and preserving the environment. Their contributions to the management of safety-critical equipment and the integration of the emerging technologies of Industry 4.0 are provided. Based on a systematic review of more than one hundred academic papers and gray literature, the authors highlight considerable gaps associated with the operations of the two systems mostly functioning without integration. The authors propose a new conceptual framework, integrated asset integrity and process safety management (iAIPSM), to address the gaps. This review provides insights to strengthen operational safety, ensure regulatory compliance, and support the advancement of the United Nations Sustainable Development Goals (SDGs) within the sector.
Examining the progress in additive manufacturing in supporting lean, green and sustainable manufacturing : a systematic review
(MDPI, 2024-07) Maware, Catherine; Muvunzi, Rumbidzai; Machingura, Tinotenda; Daniyan, Ilesanmi
The quest for waste reduction and the development of manufacturing processes that meet the economic, social and environmental requirements necessitate this study. Additive manufacturing is an emerging digital technology that can be used to seamlessly develop a product through material deposition in layers. The study aims to investigate the progress made in the development of additive manufacturing to support lean, green and sustainable manufacturing. The study employs a systematic literature review approach, specifically the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA). A total of 158 articles identified from different academic databases that detailed empirical, conceptual and theoretical findings were reviewed, having matched the selection criteria. The outcome of the study indicated that additive manufacturing can be used to achieve waste reduction, reduction in emission generation and carbon footprints with significant energy and material conservation. The findings also indicated that the additive manufacturing process also boasts time- and cost-effectiveness during manufacturing compared to the conventional manufacturing technique. Although the process is energy intensive, careful selection of the suitable additive manufacturing process to be employed based on the requirements coupled with a proper product design may result in considerable energy savings at the preprocessing, processing or post-processing stages. This work adds to the understanding of additive manufacturing and contributes to the existing literature on the relationship among additive, lean, and green manufacturing. The study may help manufacturing organizations in their quest to minimize waste generation and achieve material and energy efficiency throughout their product lifecycles.
Optimal pricing and production lot size for two rates of production with price-sensitive demand, price break-even point, and profit maximisation in higher order equation
(Southern African Institute for Industrial Engineering, 2024-05-31) Sivashankari, C.K.,; Nithya, T.; Yadavalli, Venkata S. Sarma
In the present study, optimal pricing and optimal lot size production policy models with price-sensitive demand of deteriorating products are considered, taking into account two distinct production rates. It is possible to begin production at one rate and then switch to a different rate after a period of time. Such a scenario is appealing, in that a big initial stock of produced goods can be avoided by starting production at a modest pace, thus reducing the initial investment and the holding cost. Further, the fifth-order equation is obtained when the equation for optimal pricing is derived. Maximising the profit is calculated based on a fifth-order equation. Both optimal pricing and production lot size are decision variables, and optimal cycle time is also one of the decision variables for determining price break-even points. As far as information is concerned, no researcher has examined optimal pricing and production lot size policies in two-rates-of-production models for their study. The objective of the present study is to examine the optimal production, optimal pricing, and optimal cycle time to reduce the total cost and to maximise the total profit. Both price break-even point and profit maximisation are considered. An appropriate mathematical model is developed. An illustrative example is provided and numerically validated using a sensitivity analysis. Microsoft Visual Basic 6.0 was used to code the model’s outcome validation.
Do socially responsible and risk-tailored portfolios win? A comparative analysis
(Southern African Institute for Industrial Engineering, 2024-05-31) Van Niekerk, Melissa; Trent, Nadia M.; u14048885@tuks.co.za
This study introduces three extensions of the Markowitz portfolio selection model: (1) matching portfolio risk to individual investors’ risk appetite; (2) excluding certain shares; and (3) environmental, social, and governance (ESG) integration. The models are compared to the traditional Markowitz model using empirical data from JSE Limited. The findings reveal that differentiating portfolios on the basis of risk appetites or exclusions had a limited impact on future returns. However, portfolios differentiated by ESG integration showed significantly higher future returns than the other models or industry investments. The study highlights the superiority of ESG integration and suggests that current portfolio selection models do not fully capture the art of investing.
Logistic facility identification from spatial time series data
(Elsevier, 2024-12) De Beer, Dirk Johannes; Joubert, Johan W.
Vehicle telemetry data is becoming more ubiquitous with increasingly sensorised vehicles, but making sense of the vehicles' purpose remains challenging without additional context. Clustering the vehicle activity data and identifying the underlying facilities where the activities occur reveals much insight, particularly for logistics planning. Unfortunately, current research typically only looks at a single point in time. This paper contributes by matching geospatial patterns, each representing a facility where trucks perform activities over multiple periods. The contribution is a necessary first step in studying how urban freight movement and its underlying inter-firm networks of connectivity change over time. We demonstrate how to overcome three challenges. Firstly, the complexity of identifying facilities from non-regular geometric polygons. Secondly, the challenge associated with the scale of comparing more than 200,000 facilities on a month-to-month basis over a multi-year period. Finally, overcoming the computational challenge of the workflow and getting the required performance on a consumer-grade laptop. The paper evaluates various machine learning algorithms, highlighting a SVM that outperforms more popular deep learning and neural network alternatives, with a mean average accuracy of 96.9 %.
System dynamics applied in enterprise engineering - a systematic literature review
(Emerald, 2025-01) Hussain, Huda; De Vries, Marne
PURPOSE : This study aims to investigate the combined use of System Dynamics (SD) applications in Enterprise Engineering (EE) research and practice. SD application in EE is becoming widely accepted as a tool to support decision-making processes and for capturing relationships within enterprises. DESIGN/METHODOLOGY/APPROACH : A systematic literature review (SLR) is conducted using a standard SLR method to provide a comprehensive review of existing literature. The search was conducted on ten platforms identifying 30 publications which were analysed through the use and development of a codebook. FINDINGS : The SLR showed that 90% of the result set consisted of peer-reviewed academic conferences and journal papers. The SLR identified a highly dispersed author set of 83 authors. Amongst these authors, Vinay Kulkarni was an active author who has co-authored up to four publications in this research area. The analysis further revealed that the combined use of SD applications and EE is an emerging research area that still needs to develop in maturity. While all phases of EE have received attention, the current research work is more focused on the design phase. The important gap between model development and implementation is identified. ORIGINALITY/VALUE : The study elucidates the existing status of interdisciplinary research combining techniques from the SD and EE disciplines, suggesting future research topics that combine the strengths of these existing disciplines.
A lot sizing model for a deteriorating product with shifting production rates, freshness, price, and stock-dependent demand with price discounting
(Ram Arti Publishers, 2024-06) Tshinangi, Kapya; Adetunji, Olufemi; Yadavalli, Sarma; sarma.yadavalli@up.ac.za
Many production systems need to be able to change the rate at which they manufacture products for various reasons, hence, the need to find the optimal lot size under these multiple levels of production. This research addresses the need for optimizing inventory in a system with a shifting production rate and other challenging product characteristics such as product deterioration with limited life span, and product demand that is dependent on the stock level, the state of freshness of the product, and the selling price. The product also needs to be discounted as it gets close to the expiry date in order to boost demand and prevent wastage beyond its life span. Our objective is to maximize profit by determining the optimal selling price and inventory cycle time by deriving the relevant equations for these decision variables. The Newton-Raphson method was used to numerically solve for the optimal values of these variables. Sensitivity analyses were performed to derive useful insights for managerial decision-making.
Can human lean practices affect business performance? Evidence from Zimbabwe service industries
(Emerald, 2024-09) Machingura, Tinotenda; Adetunji, Olufemi; Muyavu, Ashleigh Tatenda; Maware, Catherine
PURPOSE : This research seeks to explore the interrelationships between human lean practices (HLP) and their impact on the business performance of service industries. DESIGN/METHODOLOGY/APPROACH : A questionnaire was used to collect data from the service industries in Zimbabwe, and 260 valid responses were obtained. The questionnaire was analyzed using structural equation modeling (SEM) in SmartPLS. FINDINGS : Both the managerial human lean practices (MHLP) and employee human lean practices (EHLP) were found to positively impact business performance. Also, the MHLP had a positive relationship with EHLP. RESEARCH LIMITATIONS/IMPLICATIONS : The research focused on Zimbabwe’s service industry; hence, the results may not be readily adopted by other industries and countries without further investigations. PRACTICAL IMPLICATIONS : The improvement in business performance is centered on the activities of humans, both the employees and managers. Therefore, organizations should invest more in human resources to enhance their performance. ORIGINALITY/VALUE : Lean manufacturing (LM) is well known for its adoption in the manufacturing industry; thus, extending it to other sectors requires further research. Although a few studies have investigated the effect of adopting Lean in the service sector, they did not explore the relationship between MHLP and EHLP and the importance of such a relationship toward improved business performance.
The impact of soft lean practices on business performance : mediating role of customer satisfaction
(Emerald, 2024-11) Machingura, Tinotenda; Muyavu, Ashleigh Tatenda; Adetunji, Olufemi
PURPOSE : Many firms have adopted different methodologies such as lean management to increase customer satisfaction. This is because they need to respond to customer demands for improved products and responsive service. This study aims to evaluate the influence of soft lean practices (SLP) on business performance in the service sector. DESIGN/METHODOLOGY/APPROACH : Out of 702 questionnaires distributed to various service companies in Zimbabwe, 260 valid responses were received. Structural equation modeling was used to assess the relationship among the factors of the proposed model. FINDINGS : The implementation of SLP leads to improvement in the business performance of the service companies. However, the impact of SLP on business performance is mainly indirect, mediated by customer satisfaction. RESEARCH LIMITATIONS/IMPLICATIONS : The research focused on the implementation of SLP in the service industry of a developing country; hence, the results obtained may require further investigations before generalization to other countries with different sociocultural contexts is made. ORIGINALITY/VALUE : Most previous studies focused mainly on the implementation of the technical lean practices in the manufacturing industry without properly acknowledging the importance of SLP. This research investigates the importance of SLP in the service sector and further explores the mediatory role of customer satisfaction on business performance. The findings also validate the service-profit-chain theory.
The effect of vehicle load on urban freight emissions
(Elsevier, 2024) Joubert, Johan W.
Several city logistics initiatives focus on lowering last-mile deliveries’ environmental impacts. And here, the impact is often the total (absolute) pollutants emitted by urban goods vehicles and the population's exposure to those pollutants. Some of these interventions include the conversion of traditional fleets to clean(er) fuels or imposing vehicle access restrictions, based on emission standards, in the form of (ultra) low emission zones. Many of these interventions rely on models to predict and evaluate, a priori, what the impact will be. But, like all models, assumptions must be made, resulting in predicted results underestimating actual emissions. For urban logistics, more than for private cars, the literature shows a substantial difference between the predicted and tail-pipe emissions for most pollutants. This paper builds on prior research and shows the cargo load's nonlinear effect on emissions in an urban environment.
Electrifying an urban delivery fleet : a case study
(Elsevier, 2024) Janse van Rensburg, Cayla; Joubert, Johan W.
When carriers consider electrifying their delivery fleets, it is not only a societal and moral obligation, given road traffic's impact on emissions. It has also become an economic consideration as sustainability metrics can result in investment, and the life-cycle cost of electric vehicles is becoming more attractive. In this paper, we report on an actual case of a South African pharmaceutical company considering replacing and electrifying its current delivery fleet. The paper uses an agent-based simulation approach that models each delivery vehicle on an existing road network. Each vehicle's emissions characteristics are known, and its spatiotemporal movement results from solving a variant of the well-known routing problem. Vehicle movements are coupled with a detailed database of emissions factors to estimate the total emissions per vehicle per link, which can then be aggregated to any required level. The results show that electrifying an entire fleet may not be viable initially, suggesting a hybrid fleet as a more practical intervention in the foreseeable future.
BRT network design for transit cost reduction in Cape Town, South Africa
(Elsevier, 2023) Nnene, Obiora A.; Zuidgeest, Mark H.P.; Joubert, Johan W.
Car dependency in Cape Town, South Africa, like in many modern cities is high but comes at a high cost. One of these is significant network congestion, especially during peak commuting periods. A strategy adopted by the City’s transport development authority to alleviate this situation is the phased development of an integrated public transport network. A bus rapid transit service known as the MyCiTi BRT is proposed to be the backbone of the integrated network. However, an investigation of the existing service reveals a pattern of low ridership and high operating costs which is not economically sustainability. The main objective of this work is therefore to propose solutions to improve the existing service particularly in terms of increasing ridership and reducing operational cost. To achieve this, a network design approach known as simulation-based optimisation that combines simulation with optimisation algorithms is proposed. The results are compared with the baseline MyCiTi network. The outcome shows that the proposed methods are capable of improving the MyCiTi network and thereby its service.
Prioritizing factors influencing the performance of a supply chain system using hybrid structural interaction matrix
(Journal Management System, 2023-02) Makinde, O.A.; Mowandi, T.; Ayomoh, Michael Kweneojo; Munyai, T.T.; Nesamvuni, A.E.
Ascertaining and prioritizing the various factors that can influence the performance of a supply chain system is vital towards creating measures that are tailored towards controlling these factors, in order to ensure a sustainable supply chain. This research subject matter has been solved in the literature using multi-criteria decision making techniques, whose prioritization solutions are generated using experts opinions, which are subjective, thereby decision obtained could be prone to biases. In light of this, this study present an Hierarchical Structural Interaction Matrix (HSIM) approach, whose prioritization computation is premised on the theory of subordination derived via systems thinking, to prioritize various factors influencing the performance of a supply chain system. In order to achieve this, firstly, all the factors that could influence the performance of a supply chain system were identified from the literature. Thereafter, a Binary Interaction Matrix, which unveil the arrays of subordinations that exist amidst a number of the identified factors was developed. The result of this exercise was thereafter numerically analyzed using appropriate mathematical equations to determine the intensity rating score of each supply chain performance factor. Furthermore, Pareto analysis was conducted using the latter results, to unveil the vital few factors that could influence the performance of a supply chain system used in an organization. The result of the study unveiled that supply chain performance of an organization can be exponentially improved, if supply chain managers can focus and concentrate their management efforts more on 11 critical factors obtained from the prioritization analyses. With this approach, supply chain manager would obviously reduce errors in the ratings of the supply chain performance-driven factors.
Robust facility location of container clinics : a South African application
(Ram Arti Publishers, 2023) Karsten, C.; Bean, Willemiena Lodewika; Van Heerden, Q.; wilna.bean@up.ac.za
There is a lack of dynamic facility location models for developing countries that consider the changes in the problem environment over time, such as patient population and population migration. Therefore, this paper focuses on using optimization and goal p rogramming to locate health care facilities in an uncertain environment using multiple possible future urban development senarios To achieve this, a robust multi objective facility location model is developed and used to determine locations for container clinic deployment over multiple years in selected communities in South Africa. A synthetic population and urban growth simulation model are used to estimate population density and distribution from 2018 to 2030 for three development senarios The results from the urban growth simulation model are then used as input into the facility location model to locate facilities whilst consider ing the three future development scenarios. Results of the model indicate that the robust model can be used to find locations that provide a relatively good solution to all considered development scenarios, providing key role players with quantitative deci sion support during network design under uncertainty. An accessibility analysis investigates the impact of the prescribed accessibility percentage on model results and a budget analysis evaluates the impact of a case that includes a budget constraint. From these two analyses it is illustrated that the model is sensitive to changes in parameters and that the model can be used by key stakeholders to combine network design and urban development planning for improved decision making.
Reliability analysis of the functional capabilities of an autonomous vehicle
(Ram Arti Publishers, 2023) Ndlovu, Brain Ndumiso; Ayomoh, Michael Kweneojo; bn.ndlovu@up.ac.za
The reliability of autonomous vehicles (AVs) is a research domain of high interest, covering a diverse pool of researchers, captains of smart auto industries, government agencies, and technology enthusiasts. The reliability of AVs is not extensively explored in the literature, despite the apprehension due to fatal accidents recorded in the past. Despite being in existence for over a decade, AVs have yet to reach a certified commercial-level deployment. Due to the complexity that comes with the self-operation of an AV, the issue of trustworthiness, which signifies reliability, becomes inevitable. The identification, analysis, and categorization of functional elements using systems engineering conceptual design principles and the linkage of these to the road traffic rules were conducted to address this. Also, the evaluation of the reliability of AVs using various developed vehicles from selected industries was addressed by integrating the traffic rules. The analysis of reliability was carried out using life-to-failure data premised on the probability plotting approach. It was found that there is a 99.94% chance that an autonomous vehicle will fail at least one of the traffic rules within 20 minutes of driving. Furthermore, the hazard rate of AVs was found to be on the rise, meaning a high indication of accidents.
Impact of road grade on the risk profile of driver behavior
(Sage, 2023-02) Gerber, Jeanne-Marie; Joubert, Johan W.; johan.joubert@up.ac.za
Data generated from telemetry devices, such as acceleration and speed, are used in a variety of industries to determine the risk profile of a driver. This paper considers the addition of road gradient as a contextual variable to a driving behavior model to determine specifically if the risk of a driver is influenced by different road grades. This behavioral risk is demonstrated by comparing the performance of heavy vehicle drivers with and without the addition of road grade as a variable. This is done by using accelerometer data of 48 heavy goods vehicles over an entire month, and appending elevation data from digital elevation model (DEM) data, specifically that of the Shuttle Radar Topography Mission (SRTM), to the vehicles’ GPS traces. The elevation values are used to calculate road grade values which are then categorized in five grade levels. The results show that there is a clear influence of gradient on the behavior of the drivers studied. There is also evidence that steeper sections on a road can cause a change in an individual’s performance when compared with the group.
A comprehensive case study on integrated redundant reliability model using k-out-of-n configuration
(Gnedenko Forum, 2023-03) Velampudi, Srinivasa R.; Akiri, Sridhar; Subbara, Pavan K.; Yadavalli, Venkata S. Sarma; sarma.yadavalli@up.ac.za
Designers may introduce a system with multiple technologies in series to improve system efficiency. The configuration can be applied to k out of n systems if each technology contains k out of n factors. The k out of n configuration method is successful until every component of the system is successful. The efficiency of the entire system is more in amount than that of a single system factor in a k out of n shape. An Integrated Reliability Model (IRM) for the k out of n, here, an additional system is suggested to account for both the efficiencies of the factors and the number of factors in every phase and the different constraints to optimize the efficiency of the system. To enhance system efficiency, the authors employed the numerous methods of Lagrangean approach to determine the numbers and efficiency of the factors as well as the reliabilities of the phase under different parameters namely load, size, and cost. The dynamic programming approach and simulation method have been adapted to attain an integer result as well as to see the values real.

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