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Rika Ampuh Hadiguna
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hadiguna@ft.unand.ac.id
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Kota padang,
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INDONESIA
Jurnal Optimasi Sistem Industri
Published by Universitas Andalas
ISSN : 20884842     EISSN : 24428795     DOI : -
Jurnal Optimasi Sistem Industri (JOSI) is a peer-reviewed journal that is published periodically (April and October) by the Department of Industrial Engineering, Faculty of Engineering, Universitas Andalas, Padang.
Arjuna Subject : -
Articles 394 Documents
Optimizing the Supply Chain for Recycling Electric Vehicle NMC Batteries Fransisca Indraningsih Kasy; Muhammad Hisjam; Wakhid Ahmad Jauhari; Syed Ahmad Helmi Syed Hassan
Jurnal Optimasi Sistem Industri Vol. 23 No. 2 (2024): Published in January 2025 (published late, please read our note)
Publisher : The Industrial Engineering Department of Engineering Faculty at Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (548.594 KB) | DOI: 10.25077/josi.v23.n2.p207-226.2024

Abstract

The rapid growth of electric vehicle production has led to increased waste batteries that can no longer be used. This increase causes environmental and economic challenges. Lithium-ion battery waste harms the environment as it contains toxic and flammable chemicals. New raw materials need to be procured economically due to the need for more infrastructure and a circular economy. Therefore, the solution to overcome the impact of the accumulation of lithium battery waste is to recycle the battery. Recycling end-of-life batteries is necessary to mitigate material supply risks, reduce demand for new materials, and mitigate harmful environmental and health impacts. This study aims to provide a conceptual model for the supply chain network design of electric vehicles' Nickel Manganese Cobalt (NMC) battery recycling process. We developed a mathematical model to determine the allocation of multi-product recycling products from multi-suppliers and other related entities such as manufacturers and landfills over multiple periods. The analysis method utilizes techno-economic investment feasibility analysis and load distance method. The problem in the recycling process supply chain network is formulated in a Mixed Integer Linear Programming (MILP) model. The MILP optimization results show that the proposed model produces a globally optimal solution for allocating NMC batteries. The application of this study is to provide a solution to the treatment of waste batteries from electric vehicle end-users in Java Island, Indonesia. In addition, it can develop economic opportunities in the waste battery recycling business in the electric vehicle industry. It is building a contribution to a sustainable electric vehicle battery management system by reducing the dependence on demand for new materials from mining and analyzing the sustainability of the NMC electric vehicle battery recycling process.
The Effect of Sex Differences and Experience of Using Virtual Reality on Presence Dian Putrawangsa; Clara Theresia; Thedy Yogasara; Yansen Theopilus
Jurnal Optimasi Sistem Industri Vol. 22 No. 1 (2023): Published in May 2023
Publisher : The Industrial Engineering Department of Engineering Faculty at Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (893.526 KB) | DOI: 10.25077/josi.v22.n1.p61-68.2023

Abstract

Presence greatly affects user experience and comfort when using virtual reality (VR). Presence is often associated with personal factors such as sex differences and experience using the instrument. There is a research gap related to presence judging by several studies, so it is an interesting topic for further study. This research aims to identify the effect of sex differences and experience using VR on presence. This study used two approaches namely subjective indicators by employing an Igroup Presence Questionnaire (IPQ) and objective indicators in the form of heart rate (HR) and task scores. The study made use of Kruskal-Wallis and MANOVA to determine whether there is an effect of sex differences and experience in using VR on presence. This study found that the sex variable affects a person's presence when playing VR, especially spatial score on the IPQ test, where women have a higher marginal means value than men. Another finding is that the experience of playing VR affects the delta heart rate, with the result that someone with no experience using VR is higher than those who have used VR before.
Pendekatan Simulasi untuk Analisis Antrian pada Bengkel Servis PT. X Prima Denny Sentia; Ilyas Ilyas; Riyan Haikal
Jurnal Optimasi Sistem Industri Vol. 15 No. 2 (2016): Published in November 2016
Publisher : The Industrial Engineering Department of Engineering Faculty at Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (600.57 KB) | DOI: 10.25077/josi.v15.n2.p105-113.2016

Abstract

PT. X is an authorized dealer and service provider of a reputable car product that provides sales and maintenance services. Total number of counters and stalls owned by PT. X cannot be considered optimal based on the number of cars that will be serviced. Long queues cause customers postponinge the maintenance service and reschedule them to another day. The purpose of this study is to analyze the queue characteristic of the simulation results in the service counters and to design improvement of the scenarios. The study was conducted to implement a simulation model on a service system in order to determine an optimal number of service stations which is appropriate with the waiting time that has been targeted by the company. The analysis of the scenario carried out refers to the target that needs to be achieved by the company that is 15 minutes waiting time to call by counter and 120 minutes waiting time to service. Based on the possibilities occurred, there are 11 proposed improvement scenarios that can be applied in the company. The results from the analysis stated that scenario No. 8 that add two counters and two maintanance stalls in the service station has average waiting time which closed with targeted time set by the company. Therefore, scenario No. 8 is chosen as a proposed improvement actiion. By implementing this scenario it is expected that average waiting time to call by a counter is only on 16,845 minutes on Thursday and the average waiting time to service is only 124,63 minutes on Wednesday.   
Analisis Perhitungan Biaya Penambangan Batu Silika Pada Departemen Tambang PT Semen Padang prasticia chandra dewi
Jurnal Optimasi Sistem Industri Vol. 10 No. 1 (2011): Published in 1st April 2011
Publisher : The Industrial Engineering Department of Engineering Faculty at Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (222.64 KB) | DOI: 10.25077/josi.v10.n1.p93-104.2011

Abstract

Cement manufacturing is consisting of four components that are limestone with the percent composition of 70%, iron sand 10%, silica 10%, and clay 10%. Source of major raw materials for cement production in PT Semen Padang are limestone and silica. The mining process is involving various costs such as direct costs, indirect costs, overhead costs, etc. Therefore, cost calculations needed to determine the selling price of produced silica. In calculating the cost of production considered various aspects, such as operating costs, material costs, labor costs. So that, it can determine cost of goods production. The research objective is calculating cost of goods manufacturing the silica. Benefit of the research for PT Semen Padang is describing cost of goods production in determining cost of goods sold. Cost of goods production that resulted for silica mining is IDR 58.000 per ton, while internal price of silica is IDR 53.851 per ton. Research result is show that there is difference between results based on Full costing method with current price. This shows that several other factors is necessary considered in calculating the cost of goods production. Keywords: Mining, silica, cost of goods production
Model EPQ Multi Item yang Dimodifikasi untuk Dua Permintaan secara Simultan Taufiq Rahman; Jonrinaldi Jonrinaldi; Henmaidi
Jurnal Optimasi Sistem Industri Vol. 16 No. 1 (2017): Published in May 2017
Publisher : The Industrial Engineering Department of Engineering Faculty at Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1482.268 KB) | DOI: 10.25077/josi.v16.n1.p1-9.2017

Abstract

Inventory is one of many factors of the business operation that need to be controlled by industries in order to improve efficiency, enhance productivity, and decrease the holding cost. The holding cost of inventories in supply chain contribute to 20% - 40% of the product value. It can be controlled by applying appropriate inventory model, such as EPQ/Economic Production Quantity and EOQ/Economic Order Quantity. EPQ is an inventory model that used to determine the optimum production lot size with balanced the production setup cost and holding cost. Even the classic EPQ has applied widely in industries, the assumption used by this model differed between the researchers whether it is continuous or discrete demand, because the multi delivery or discrete demand is mostly used by industries. Even so, there are industries that used both continuous and discrete demand simultaneously. Based on previous research, there was an advanced EPQ model that synchronizing both assumptions simultaneously, but it still addressed single item problem. Since almost the industries produced multi item, this model has lack of applicability. Therefore, this research proposed a multi item EPQ Model that synchronizing continuous and discrete demand simultaneously. The solution procedure that used in this proposed model are classical calculus method/differential calculus and simultaneous approach. A numerical example is given to show the effectiveness of the proposed approach based on the data from the literature.
Lean Analysis Framework for Waste Management: A Case of Indonesian Textile Company Widyatmoko Reza Prambudi; Ida Giyanti
Jurnal Optimasi Sistem Industri Vol. 20 No. 1 (2021): Published in April 2021
Publisher : The Industrial Engineering Department of Engineering Faculty at Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/josi.v20.n1.p11-21.2021

Abstract

This study aims to propose a lean analysis framework for waste management and to test it into the field case. The proposed framework was applied in a weaving process of a textile company in Indonesia. The seven classical Lean wastes were identified using value stream mapping (VSM). The result was then analyzed using the waste assessment model within which waste relationship matrix (WRM) and waste assessment questionnaire (WAQ) according to the answers of the head of weaving division studied. The major source of wastes was then determined utilizing the value stream analysis tool (VALSAT). In order to thoroughly examine the root cause of such dominant wastes and to propose corrective plans to minimize the waste, a fishbone diagram was used. As the main result, this study provides a lean waste analysis framework with examples to orientate managers about wastes. Particularly in our specific case, the results demonstrate that the waiting and defect become the most significant wastes that need to be treated. These findings allow a company to organize its activities and select tools or practices to optimize its efforts to create proper corrective plans in eliminating waste. In our study, the plans include periodic maintenance of weaving machines, clear division of tasks on the distribution of weft yarns, and eliminating unnecessary activities. In addition, it is mandatory to ensure the quality of warp yarns delivered to the weaving process as well as to perform a periodic calibration of equipment on weaving machines. This study advances in the theoretical and practical field by showing a structured way to incorporate lean analysis that can be adopted for any organization.
Hubungan Phantom Vibration Syndrome Terhadap Sleep Disorder dan Kondisi Stress Ajeng Yeni Setianingrum
Jurnal Optimasi Sistem Industri Vol. 16 No. 2 (2017): Published in October 2017
Publisher : The Industrial Engineering Department of Engineering Faculty at Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (803.32 KB) | DOI: 10.25077/josi.v16.n2.p158-166.2017

Abstract

Phantom vibration syndrome is a condition where a person would feel the sensation of vibration of a cell phone as if there were incoming notification but the fact is not. This research investigated the relationship between phantom vibration syndromes, sleep disorder and stress condition. Questionnaires were distributed to 120 participants with age range 18 to 23 years old. Data of participants showed that all of participants using a smart mobile phone and 24% of them have more than one cell phone. Time usage of cell phone is at least 1 hour. 23% of participants using a cell phone for social media activity, followed by 21% related to entertainment (music, video and games). The results showed a positive relationship between phantom vibration syndrome, sleep disorder and stress condition. Insomnia contributed a greater influence on stress condition. However, the phantom vibration syndrome is more directly affecting the sleep apnea compared to insomnia and stress condition. Therefore, the phantom vibration syndrome more affects stress condition indirectly, through sleep disorder (sleep apnea and insomnia). Consequently, phantom vibration syndrome has a strong relationship with stress condition at the time of the phantom vibration syndrome can cause sleep disorder.
Identification of Internal Academic Factors Affecting Academic Entrepreneurship: A Case Study Prima Fithri; Rida Rahim; Donard Games; Alizar Hasan; Ikhwan Arief
Jurnal Optimasi Sistem Industri Vol. 20 No. 2 (2021): Published in October 2021
Publisher : The Industrial Engineering Department of Engineering Faculty at Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (142.464 KB) | DOI: 10.25077/josi.v20.n2.p72-82.2021

Abstract

Academic Entrepreneurship is an entrepreneurial activity conducted by scientists/academics who market their research results commercially to achieve specific economic benefits or rewards. This research focuses on academic entrepreneurship that occurs at Andalas University. There is still a lack of academics whose research products for commercialization are about 22.73%. It is because there are factors that influence academic entrepreneurship activities at Andalas University. One of them is the internal academic factor. The internal factors are Control System, Organizational Culture, Human Resource Management System, Organizational Structure, and Academic Leadership Behavior. The purpose of this study is to analyze the university's internal factors on academic entrepreneurship. This research uses a quantitative approach derived from 106 Andalas University academics with Structural Equation Modelling (SEM) methods with SmartPLS Software. The result obtained in this study is that the control system exerts a positive and negative influence on academic entrepreneurship. In contrast, other factors have a significant positive influence on academic entrepreneurship. The research results show that the university's control system, organizational structure, and human resources had no significant positive effect on academics at Andalas University. Meanwhile, entrepreneurial behavior and organizational culture have a significant positive effect on academic entrepreneurship at Andalas University. Further research should be analyzed for all universities with innovative products and are ready for commercialization throughout Indonesia. This research is still a case study and needs to be developed.
Enhanced Sustainability Assessment Framework for Plywood Manufacturing: A Multi-Method Approach Using Delphi Technique, BWM, and S-VSM Annisa Kesy Garside; Tyas Yuli Rosiani; Adelya Amanda; Thomy Eko Saputro; Eduardo e Oliveira
Jurnal Optimasi Sistem Industri Vol. 23 No. 2 (2024): Published in January 2025 (published late, please read our note)
Publisher : The Industrial Engineering Department of Engineering Faculty at Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (604.955 KB) | DOI: 10.25077/josi.v23.n2.p188-206.2024

Abstract

Sustainable manufacturing has emerged as a critical priority in addressing the complex environmental, social, and economic challenges of modern industry. This study focuses on the plywood sector, a significant contributor to manufacturing, which faces distinct sustainability issues such as high energy consumption, material inefficiencies, and hazardous working conditions. To address these challenges, the research introduces workload and noise level as critical indicators for assessing sustainability, broadening the scope of traditional evaluation methods. A multi-method framework was employed, integrating the Delphi technique to identify key sustainability indicators, the Best Worst Method (BWM) to assign weights to these indicators, and Sustainable Value Stream Mapping (S-VSM) paired with a Traffic Light System (TLS) to evaluate and visualize the Manufacturing Sustainability Score (MSS). Applied to a plywood manufacturing case study, the framework highlighted areas requiring improvement, particularly in worker well-being and operational safety, while demonstrating the industry's moderate overall efficiency. By offering actionable insights for improving resource use, operational processes, and employee conditions, this framework provides a practical tool for industry managers aiming to enhance sustainability. Furthermore, its adaptability makes it a valuable reference for other manufacturing sectors seeking to implement resource-efficient and sustainable practices. This research not only fills critical gaps in sustainability assessment but also contributes to advancing industry practices by emphasizing holistic and innovative approaches to manufacturing efficiency.
Aplikasi Algoritma Hybrid dalam Penentuan Rute Pendistribusian Produk (Studi Kasus: PT. Enseval Putera Megatrading) Eri Wirdianto; Dhina Regenie; Wisnel Wisnel
Jurnal Optimasi Sistem Industri Vol. 15 No. 2 (2016): Published in November 2016
Publisher : The Industrial Engineering Department of Engineering Faculty at Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (440.442 KB) | DOI: 10.25077/josi.v15.n2.p171-180.2016

Abstract

PT. Enseval Putera Megatrading is a company which operates in general business and distribution of pharmacy products, general needs, cosmetics, foods and hospital equipment. In their current practice, routing in products deliveries, which is limited by time windows, has not considered the utilization of vehicles' maximum loading capacities. Distribution route from a hybrid algorithm using heuristic clustering and Mixed-Integer Linear Programming approach can accommodate such problem with time windows and vehicles' capacities utilization. Based on the comparison between company’s current route and the route from the hybrid algorithm, it can be seen that the hybrid algorithm is able to decrease total distance and total cost of transportation. This new route concerns on vehicles allocation and time windows limit. This new route can minimize the total cost of transportation that company has to pay.

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