Browsing by Author "Dewa, Mendon"

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An adaptive neuro-fuzzy inference scheme for defect detection and classification of solar Pv cells
(Academy Publishing Center, 2024-09-12) Moyo, Ranganai Tawanda; Dewa, Mendon; Romero, Héctor Felipe Mateo; Gómez, Victor Alonso; Aragonés, Jose Ignacio Morales; Hernández-Callejo, Luis
This research paper presents an innovative approach for defect detection and classification of solar photovoltaic (PV) cells using the adaptive neuro-fuzzy inference system (ANFIS) technique. As solar energy continues to be a vital component of the global renewable energy mix, ensuring the reliability and efficiency of PV systems is paramount. Detecting and classifying defects in PV cells are crucial steps toward ensuring optimal performance and longevity of solar panels. Traditional defect detection and classification methods often face challenges in providing precise and adaptable solutions to this complex problem. In this study the researchers pose an ANFIS-based scheme that combines the strengths of neural networks and fuzzy logic to accurately identify and classify various types of defects in solar PV cells. The adaptive learning mechanism of ANFIS enables the model to continuously adapt to changes in operating conditions ensuring robust and reliable defect detection capabilities. The ANFIS model was developed and implemented using MATLAB and a high predicting accuracy was achieved.
Comparative analysis of specific energy consumption and energy consumption benchmarking in galvanising plants
(IEOM Society International, 2022-08-04) Dewa, Mendon
The inadequacy of sustainable energy is endlessly posing major challenges globally. The issue of energy optimisation is indispensable for manufacturing sector, particularly for a hot-dip galvanising process where galvanising furnaces are the significant energy users. This study is aimed at comparative analysis of specific energy consumption and energy consumption benchmarking in four galvanising plants with the view to necessitate the identification of best practices. Energy baselines were used as quantitative reference points to compare energy performance indicators and quantify fluctuations in energy performance during the baseline and reporting periods. A quantitative analysis was also conducted to benchmark four galvanising facilities on factors that included the electricity/zinc ratio, electricity /dips ratio and product tonnage/zinc used ratio. The results revealed improved performance for plant 4 over time relative to the baseline consumption when compared to plants 1, 2 and 3. Plant 4 also outperformed other facilities after the energy efficiency interventions in terms of electricity/zinc ratio and electricity/ product tonnage ratio. Given the disparity between the results of specific energy consumption (SEC) for the four plants, it was concluded that SEC alone should not be used as an energy performance indicator.
Cultural difference and IT project success : a fallacy or reality on the South African ICT sector
(Southern African Institute for Industrial Engineering, 2022-10-03) Javani, Blessing; Thabe, Mogolodi; Dewa, Mendon; Hattingh, Teresa
With high incidences of IT project failure in South Africa and globally. The paper aims to raise awareness of the impacts that cultural differences can have on IT project success, if not appropriately incorporated in project risk planning for practitioners and academics. Data was collected through semi-structured interviews on 15 IT project managers. The research demonstrates that most IT project managers do not regard cultural differences as a risk to project success, and do not regard the impacts that cultural differences of project stakeholders could have on a project as necessary for inclusion in project risk planning. The paper suggests that IT project managers and project team members should be culturally aware and sensitive and that one of the ways to address the impacts of cultural differences in IT projects is to promote trust, collectivism with a team identity in multicultural project settings thereby enhancing project success.
Deploying built-in quality to reduce scrap in an automotive component manufacturer
(SAIIE, 2024-05-31) Dewa, Mendon; Makua, Edward
Automotive component manufacturers face global competitive challenges, and the paradigm has shifted from product price as the determining factor of competitiveness to the quality of the product. An automotive component manufacturer was struggling to manage the outflow of defects, and adding inspectors as quality gates to the rear-step bumper production line had severe cost implications. This study aimed to reduce the number of defects by deploying a strategic path of implementing built-in quality. Quality tools were used, and the study’s results included significant manpower reduction, improved quality capability, and reduced scrap rates and reworks.
An effective ergonomic programme to improve performance in the packaging industry
(PONTE, 2022-06-23) Dewa, Mendon; Ramdass, Kemlall; Roopnarain, Riashna
The packaging industry in South Africa is devoid of effective ergonomic programmes due to poor implementation thereby leading to failure to yield realisable benefits for the implementing firms. The study aims to develop an effective SEP that focuses on improving the firm's overall performance through synchronisation of the ergonomic programmes with the firm's business strategy. A quantitative research methodology with a questionnaire as the research instrument was adopted for this study. A quantitative research methodology was adopted to elicit information from the employees at a liquid packaging company in South Africa. A sample of 70 employees from engineering and production departments was used. The research findings demonstrated that several factors hindered the effective implementation of ergonomics in the packaging industry, and these include awareness in the subject of ergonomics, job task design, human-computer interaction, disconnection between organisational strategies and employees, as well as poor implementation of physiological and anthropometric factors. An effective ergonomic programme that incorporated systems engineering risk assessment methodology, was developed, embracing a probability of occurrence matrix, ratings of criticality and rating of consequences. It was recommended that the organisation should train the employees on ergonomics best practices to create an effective programme that will eliminate operational gaps and lead to enhanced organisational performance.
Effective risk management practice and project success : the case of a water utility’s construction projects
(Southern African Institute for Industrial Engineering, 2022-10-03) Javani, Blessing; Mamena, H.G.; Dewa, Mendon
Failure to complete projects can significantly put an organisation’s competitive advantage, its strategic position, and competitive survival in jeopardy. The study sought to establish the effectiveness of applying project risk management tools and techniques at Rand Water, a state-owned entity. A quantitative approach with a survey research strategy was used in this study and 63 of the total population of 69 responded to the questionnaire that was issued. The Rand Water case study findings suggest that, in order to reduce project failure, one of the tools being utilized in managing projects is effective project risk management. In addition, the findings indicate that executive management must continue to apply project risk management tools and techniques coupled with regular project team training.
Energy assessment and scheduling for energy optimisation of a hot dip galvanising process
(2021-12-01) Dewa, Mendon; Nleya, Bakhe; Dzwairo, Bloodless
The dearth of energy sustainability is posing major challenges both locally and glob- ally. Galvanising furnaces are categorised as dominant consumers of electricity in the overall galvanising industry. Relatively little research has been carried out concerning energy optimisation through sequencing or scheduling algorithms by way of enhancing the performance of galvanising lines. In this regard, the research centres on evaluating overall energy performance in this industry. The research sought to introduce an opti- mal energy optimisation-scheduling algorithm for a hot dip galvanising process. A DMAIC based methodology was presented for the provisioning of a structured prob- lem-solving process for improving energy efficiency in a galvanising process. Its framework embraces an energy sustainability assessment of four batch hot-dip galva- nising plants. Four energy minimisation opportunities were identified and quantifiable energy and cost savings, as well as avoided carbon dioxide emissions were derived from the analysis of one of the plants. Production or zinc used was identified as the main driver for electricity consumption for Plant 1, while the number of dips per month, amount of zinc used, and ambient temperature conditions were identified as the rele- vant variables for developing a regression model for Plant 2. The amount of zinc used and ambient temperature conditions were found to be the relevant variables for Plant 3. The derived regression model for Plant 4 was based on the amount of zinc used and ambient temperature conditions. The energy performance indicators for a galvanising plant were established through a comparison of actual and expected consumption, energy intensity index, cumulative sum, and specific energy consumption. A bi-objective GECOS algorithm was further introduced to reduce the total energy consumption as well as makespan. The simula- tion results revealed that the GECOS algorithm outperforms McNaughton’s algorithm, Shortest Processing Time Algorithm, and Integer Linear Programming algorithms on minimising makespan on parallel processing machines. The key contributions to the body of knowledge from the study include a unique eval- uation of electrical energy consumption by a hot-dip galvanising plant, development of an energy consumption baseline and performance indices, and the developed novel bi-objective GECOS algorithm that considers reducing total energy consumption by the process tanks as well as makespan. Future research work may focus on hybrid genetic algorithm-artificial immune system scheduling tools that would derive synergy from the advantages of both algorithms to improve energy performance.
Energy-aware lightpath routing algorithm for optical transport networks
(TELKOM, 2019-09-01) Gomba, Ndadzibaya Masimba; Nleya, Bakhe; Dewa, Mendon; Mutsvangwa, Andrew; Khumalo, Zephaniah Philani
Current as well as future applications and services are characterized by bandwidth intensiveness and as such are directly driving the need for the deployment as well as operation of backbone networks that optimize on bandwidth provisioning. Since infrastructural hardware equipment requirements are trebling every two years because of continued surging bandwidth demands, the telecommunication industry is also a growing direct contributor to worldwide greenhouse gases (GHG) emissions as well as energy consumption. This is driving necessities to research on more energy efficient networking approaches. A novel optimized energy-aware lightpath routing (OEA-LR) algorithm is herein proposed. It primarily takes into account the effects of physical layer impairments (PLI) since their effects in high capacity translucent optical networks may not be ignored when formulating routing and wavelength assignment (RWA) algorithms. We assume an all-optical network hence connection requests from source to destination are entirely provisioned in the optical domain, thus optical-electrical-optical (OEO) conversions are not utilised. Both analytical and simulation results indicate that the proposed algorithm improves both energy efficiency operation as well as resource utilization of the network. We further conclude on a general observation of reciprocations between energy savings and blocking performance.
Exploring the challenges and resilience of child and youth care workers employed in a child and youth care centre in KwaZulu-Natal, South Africa
(Durban University of Technology, 2023) Dewa, Sindisiwe; Dewa, Mendon
Child and youth care work is a stressful profession that results in workforce concerns about poor levels of staff retention and high levels of inexperience. The aim of this study is to gain insight into child and youth care workers’ resilience by examining the challenges faced by these workers and establish the methods used to overcome these challenges. This study employed a qualitative research method and data was collected from a child and youth care centre in Durban, KwaZulu-Natal, employing a purposive sampling technique using 9 workers. Seven themes emerged from this study and it was evident that the respondents shared a common understanding of resilience. It was also found that an individual’s grassroots had an impact on developing a passion to work with young people as well as coping with work challenges. Positive protective factors that emerged were support systems in the organisation as motivators as well as maintaining a balance between work and personal life, while negative factors were low salaries and poor working conditions. The study concluded by recommending organisational interventions to support resilience in child and youth care workers and maintain expertise in child and youth care work.
The implementation of an andon production management system to improve the efficiency of tracking of output scores
(Southern African Institute for Industrial Engineering, 2023-10-31) Dewa, Mendon; Govender, Prenisha
With the rapid ever changing technological advances, simple processes are easily changed from manual to automated. An automotive company struggled to keep track of their hourly target as well as the shift production scores. This was crucial to the production line management as this posed as a difficulty to determine the line overall efficiency as well as the possible factors of downtime. This paper is aimed to improve the tracking of hourly scores on a moving conveyor using an automated production management Andon system. Using the PDSA cycle, this automated system was implemented which made capturing of scores easier and more efficient. Once implemented, the daily downtime analysis report could be analyzed and factors affecting the production score were further investigated by the production line management. These contributors were then addressed with implemented countermeasures resulting in a high efficiency line as well as correctly tracked hourly scores.
Implementation of fuzzy logic in scheduling a flexible manufacturing system
(Southern African Institute for Industrial Engineering, 2023-10-31) Dewa, Mendon
A flexible manufacturing system (FMS) has the advantage that it can easily adapt to equipment malfunctions and changes in the quantity or type of the product being processed. Proper scheduling is critical for production planning in order to meet customer demand. The case study organisation has been facing challenges in meeting due dates while concurrently minimising lead time and maximising machine utilisation. This paper presents the deployment of fuzzy logic in scheduling a flexible manufacturing system. The proposed approach identifies scheduling parameters for routing parts through system and membership functions and fuzzy rules are constructed to develop the best schedule using a toolbox on a MATLAB fuzzy logic platform. After comparison of several priority rules for job sequencing, the results demonstrated the applicability of fuzzy logic as a decision tool in the scheduling of flexible manufacturing systems.
Improvement of a beer packaging line through Pareto analysis, root cause analysis and statistical tracking
(Southern African Institute for Industrial Engineering, 2021-10-04) Dewa, Mendon; Hatting, Teresa
It is imperative for players in the beer industry to increase efficiency continuously to stay ahead of the competition. The prevailing performance of a beer packaging line in terms of engineering stops at the case study plant was below the target set by management, and therefore improvements were vital. This paper outlines the improvement of a beer packaging line through Pareto analysis, root cause analysis, and statistical tracking at a beer producer. The procedure commenced with gathering the data for the line and conducting a Pareto analysis on beer loss. It was found that bottle conveyors' downtime was caused by bottle breakages which was also resulting in beer loss. A root-cause analysis was conducted for high filler fallen bottle stoppages and possible solutions for process improvement were then formulated and the best solution was implemented. T-Tests were finally deployed as a means of statistical tracking and the results demonstrated a significant process improvement.
Improvement of material handling system for coil transportation in the manufacture of aluminium rolled products
(Southern African Institute for Industrial Engineering, 2021-10-04) Dewa, Mendon; Hattingh, Teresa
The manufacture of aluminium rolled products is characterised by coil transportation, which is a process of moving the metal and lot tickets from one point to another for further processing at other sub-plants. The case study organisation is facing challenges on coil transportation and hence failed to deliver material on time and could not achieve manufacturing targets. The paper aims to identify the factors leading to the failure of achieving targeted schedule and introduce the system to standardize the process. As methodology, a flow diagram was used represent the current process and a failure mode and effect analysis was conducted to document and analyze the failures and implement mitigating factors. Breaking up of batches and delayed material arrivals to processing stations were found to be the key reasons that led to process inefficiency. An improved process flow was proposed and the recommended actions led to a streamlined flow characterised by reduced delayed material arrivals and processing.
Maintenance management and impact on organisational performance : a power utility perspective
(Southern African Institute for Industrial Engineering, 2022-10-03) Javani, Blessing; Jafta, N.; Dewa, Mendon
Increased plant availability, equipment reliability and safety and health of the personnel have become the significant aspect of the maintenance function within power generation. This paper positions maintenance functions and their impact on organizational performance from a power utility perspective. Research data was collected based on semi-structured interviews on thirteen maintenance engineering management personnel. The findings indicate that the challenges facing maintenance teams in executing maintenance activities include, ageing plant, staff shortage, lack of skills and knowledge and low employee morale. The paper recommended adoption of world class maintenance framework, for maintenance to achieve greater operational performance.
Mixed model line balancing for manual assembly system
(Southern African Institute for Industrial Engineering, 2023-10-31) Dewa, Mendon
It is imperative for organisations in the automotive industry to adopt a culture of continuous improvement due to a highly competitive market environment. An automotive manufacturer had adopted a takt time of 60 minutes but has been facing challenges in meeting the daily target of vehicles produced per day. The challenges were attributed to the imbalance of the assembly line and waste generated from non-value adding activities. The focus of this work is to improve a manual automotive assembly system. Time studies were conducted, a list of tools and shovel-ware components was compiled, and work stations were allocated to all the operations. After line balancing, the bus trailer was moved from the sub-assembly bay to the production line leading to more productivity. Additionally, the centralisation of bus trailer allowed for the optimal use of the tools, and the savings that were derived amounted to R350 000 per year.
Optimisation of a flexible manufacturing system through the application of greedy knapsack heuristic
(Southern African Institute for Industrial Engineering, 2022-10-03) Dewa, Mendon
The global manufacturing industry is currently facing intense competitive pressure that requires better efficiency, effectiveness and continuous improvement of the manufacturing systems. Production planning in flexible manufacturing systems is crucial for the efficient organisation of production resources to ensure economic effectiveness and meet schedule requirements without violating capacity constraints. The objective of this paper is to develop a cost-effective assignment of parts to a flexible manufacturing system (FMS) through the application of Greedy Knapsack heuristic. A production-planning problem was formulated, the objective function and associated constraints were stated and an Excel based tool was developed to generate solutions Greedy Knapsack heuristic. The tool would assign the best selected parts to the semi-automated FMS in an optimal manner to the production plan. The sample computational results were presented for Greedy Knapsack heuristic, and conclusions were drawn for the flexible manufacturing system.
Parallel processors scheduling algorithms to minimise makespan in a galvanising plant
(Ponte Academic Journal, 2020-03) Dewa, Mendon; Nleya, Bakhe
Galvanising lines consist of load/loading stations and a series of processing tanks that are generally energy-intensive. Each raw workpart needs to go through a number of processing stages sequentially. Job sizes and processing time vary from part to part, hence the need to derive an optimal schedule to minimise total processing time in a batch. The problem of minimizing the makespan on parallel processing machines using different scheduling algorithms is studied in this paper. A set of 50 independent tasks were scheduled on parallel processors in order to minimize schedule length using Integer Linear Programming, Shortest Processing Time, Longest Processing Time, and Greedy Genetic algorithms. The experimental results demonstrated that our Greedy Genetic algorithm outperformed other algorithms on minimizing makespan on parallel processing machines.
Process improvement for the manufacture of excavator bucket for a construction equipment manufacturer
(Southern African Institute for Industrial Engineering, 2022-10-03) Mdletshe, Mfundo; Dewa, Mendon; Hattingh, Teresa
A construction equipment manufacturer procured the SK220 excavator machine from Japan without the bucket. Given the poor quality of outsourced buckets, the company considered manufacturing its own strong and reliable excavator buckets. However, due to Covid 19 pandemic, the company failed to deliver the buckets on time, which affected committed customer orders. The aim of the paper is to pinpoint the bottlenecks within the supply chain and institute some corrective and preventive actions to improve the manufacture of excavator bucket for the construction equipment manufacturer. Capacity planning was conducted to establish the weekly production capacity for the excavator bucket, considering the number of workers and equipment. Root cause analysis was conducted to pinpoint all the waste that characterised the supply chain and significant counter-measures were implemented. The results demonstrated significant productivity improvement, waste reduction and average in monthly sales amounting to R6 250 000.
Process improvement for traditional mould making process through group technology and rank-order clustering algorithm
(PONTE, 2022-06-23) Dewa, Mendon; Pancha, Uttam Bhana
The current environment of changing market trends that include mass customization, sustainability, environmental impact and localized production drives the manufacturing industry to strive for additive manufacturing because of the versatility of the technology. Injection Moulding Company (IMC) is using traditional manufacturing approaches which compromise its competitiveness resulting in decreased production rate and high operational costs due to lengthy changeover times. The aim of the study was to investigate the usage of group technology and rank-order clustering algorithm as mechanisms to aid the reduction of manufacturing lead time for the traditional mould making process. ABC mould demand classification analysis conducted for the top 16 moulds revealed that the moulds for the switch cover ranked highest in terms of the demand of moulds that were fabricated by IMC. The value stream map revealed that there was room for improvement in terms of push to pull and frequent lot transfer, standardising work, reducing cutting time and process scrap, as well as introducing poka yokes and cellular manufacturing, and it was proposed to reduce material movements and setup times. Through the deployment of group technology and rank clustering algorithm, three mould families and three machine cells were derived. As a result, the mould fabrication process was improved by reducing material movements and reducing setup times.
Reduction of excessive claim costs associated with damaged cardboard cartons in distribution
(Southern African Institute for Industrial Engineering, 2022-10-03) Dewa, Mendon; Biyela, Khayelihle
Courier services suffer a severe problem of experiencing parcel damages that lead to customer complaints and carton claims. Cardboard cartons are easily prone to being damaged during transition and courier companies are not always accountable for parcel damages but still endure consequences as claim costs continue to rise every financial year. The Plan-Do-Check-Action system was used to collect and analyze data intending to prioritize problems, and a parcel inspection was conducted for 22 suppliers to measure variables. Correlation analysis was conducted, and results showed a strong correlation between weight, size, internal carton utilization, and flute corrugated size used on a cardboard. A fish-bone diagram was used to represent the potential root-causes, as a result the relationship between these variables has proven to have the most impact on parcels being damaged. The correlation between the flute corrugated size and internal carton utilization along with mishandling of stock impacted damages the most. During the movement, the durability of the carton is highly depended on these variables. An implementation of training and awareness on how to handle stock with care was conducted to reduce damages during distribution while optimising operations.