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Jurnal Optimasi Sistem Industri

JOSI
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Published by Universitas Andalas

ISSN : 20884842 EISSN : 24428795 DOI : -

Control & Systems Engineering Decision Sciences, Operations Research & Management Engineering Industrial & Manufacturing Engineering Mechanical Engineering

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.

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Articles 394 Documents

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Physiological Signals as Predictors of Mental Workload: Evaluating Single Classifier and Ensemble Learning Models Izzah, Nailul; Sutarto, Auditya Purwandini; Hendi, Ade; Ainiyah, Maslakhatul; bin Abdul Wahab, Muhammad Nubli
Jurnal Optimasi Sistem Industri Vol. 22 No. 2 (2023): Published in December 2023
Publisher : The Industrial Engineering Department of Engineering Faculty at Universitas Andalas

With a growing emphasis on cognitive processing in occupational tasks and the prevalence of wearable sensing devices, understanding and managing mental workload has broad implications for safety, efficiency, and well-being. This study aims to develop machine learning (ML) models for predicting mental workload using Heart Rate Variability (HRV) as a representation of the Autonomic Nervous System (ANS) physiological signals. A laboratory experiment, involving 34 participants, was conducted to collect datasets. All participants were measured during baseline, two cognitive tests, and recovery, which were further separated into binary classes (rest vs workload). A comprehensive evaluation was conducted on several ML algorithms, including both single (Support Vector Machine/SVM and Naïve Bayes) and ensemble learning (Gradient Boost and AdaBoost) classifiers and incorporating selected features and validation approaches. The findings indicate that most HRV features differ significantly during periods of mental workload compared to rest phases. The SVM classifier with knowledge domain selection and leave-one-out cross-validation technique is the best model (68.385). These findings highlight the potential to predict mental workload through interpretable features and individualized approaches even with a relatively simple model. The study contributes not only to the creation of a new dataset for specific populations (such as Indonesia) but also to the potential implications for maintaining human cognitive capabilities. It represents a further step toward the development of a mental workload recognition system, with the potential to improve decision-making where cognitive readiness is limited and human error is increased.

Perancangan Model Pengukuran Kinerja Green Supply Chain Pulp dan Kertas Hendra Saputra; Prima Fithri
Jurnal Optimasi Sistem Industri Vol. 11 No. 1 (2012): Published in 1st April 2012
Publisher : The Industrial Engineering Department of Engineering Faculty at Universitas Andalas

Green supply chain performance measurement system is required to manage environmental risk, increase competitive and obtain appropriate strategy for company. Performance measurement system in PT RAPP only focus on midstream and downstream operation related with manufacturing processes and supplier. The problem is how to redesign existing performance measurement system for pulp and paper in PT RAPP, so that downstream operation related with distributor can be integrated into green supply chain performance measurement system. Research objective designing conceptual and computer model for green supply chain measurement of pulp and wherein information entire supply chain can be managed well. Conceptual model is designed with involving activities such as stakeholder identification, stakeholder green requirement analysis, green objective identification, and KPI weighting. Supply chain operations reference (SCOR) metric is applied to identify key performance indicator (KPI). KPI weighting is determined by AHP method. Computer application is designed by combining database, mathematical formulation, and user interface. it is designed to implement conceptual model. Research result is consisting of two levels with fifteen objectives and twenty seven KPI’s. Proposed application has capability to support decision maker in calculating partial and total performance measure each period. It is designed specifically with quantitative measure to support operational decision making related with environmental aspect.Keywords: Green, supply chain, SCOR, performance measure

Desain dan Analisis Artificial Exoskeleton pada Prajurit TNI Salam, Rudi; Iqbal, Mohammad; Hasanuddin, Iskandar
Jurnal Optimasi Sistem Industri Vol. 17 No. 2 (2018): Published in October 2018
Publisher : The Industrial Engineering Department of Engineering Faculty at Universitas Andalas

Soldier’s activities resulted in too much workload received by the body, especially in the back and waist. These conditions produce a high risk of musculoskeletal disorders especially if conducted continuously. The soldiers must carry a backpack containing supplies during training weighing up to 40 kg on average. All activities are conducted manually until the training is finish. Thus, the purposes of this study are to reduce spinal injury by identifying factors resulting from lifting loads that exceed the limits of the body, calculate the maximum load limit that can be carried by a soldier, and produce artificial exoskeleton as a tool for the Indonesian Armed Forces. The study used anthropometry, biomechanics, and physiological approach in solving the problem. The results show that the safe load can be carried by the soldiers is 30.46 kg. The body parts that feel the complaint are the upper neck, back, shoulder, buttocks. In addition, this study can produce a design of an artificial exoskeleton with the following dimensions: chest thickness 23 cm, chest width 32 cm, back length 52 cm. The soldiers can increase the force load by 9% of the initial weight of the load using this design.

The Relationship between Work Experience, Qualifications, Performance, and Staff Perception of Digital Talent in the Workplace Irwan Noor; Nur Ambulani
Jurnal Optimasi Sistem Industri Vol. 22 No. 1 (2023): Published in May 2023
Publisher : The Industrial Engineering Department of Engineering Faculty at Universitas Andalas

The biggest challenge in developing digital talent in tertiary institutions is viewing digital reform as a massive entity. Therefore, it is rare to focus on the values of developing digital talent for existing education personnel. Using a growth theory mindset, the research focuses on Working Period, Performance, and Qualification, to see the relationship with Talented education staff. The research uses a sequential explanatory design. The sample consisted of 29 ASNs in one of the faculties of a state university in Indonesia, with random sampling using the online Sample Size Calculator. Questionnaire data were analyzed by SPSS, while interviews with NVivo-12 Pro. The results reveal that both the Working Period, Qualification, and Performance variables correlate with the Talented education of staff. The direction of the relationship also has a positive (+) value. However, qualitative analysis revealed that the activities carried out were more directed at fulfilling the main duties and functions. Behind that, the biggest challenge for them is when dealing with students, who generally come from the digital generation. Therefore, digital reform in higher education also pays attention to developing digital talent for education staff.

Peningkatan Mutu Proses Pembuatan Cat Solvent dengan Metode Taguchi di PT JI Azwir, Hery Hamdi; Mahfud
Jurnal Optimasi Sistem Industri Vol. 17 No. 1 (2018): Published in April 2018
Publisher : The Industrial Engineering Department of Engineering Faculty at Universitas Andalas

In a manufacturing process, quality is not only seen from the final product, but also manufacturing process. PT JI located in Cikarang is a company that produces paints and powder coating. Currently, the company has problems with 24.16% products that need rework or additional process. To increase productivity, PT JI applies the A3 project that is Right First Time (RFT). RFT is how to create a product with a one-time process and produce a product that has good quality on the first test. The average percentage of total RFT products in September 2016-January 2017 was 75.84%. This result is still below the company target of 80%. This study found the source of problems analyzed the manufacturing process using control chart, process capability, fishbone, and pareto. Taguchi method and ANOVA are applied to improve the design process. The application of the Taguchi Method shows that the factors which influence the value of viscosity quality are number of White Spirit, Number of Genekyd, Total Tio2 (kaolin), and mixing temperature, where each factor has an optimal level of 26.01%, 56.07%, 18.78% and 45oC. Then, it is found that all control factors have significant effect on viscosity value from ANOVA analysis. The application of this Taguchi method increases the process capability to Cp = 1.68 and Cpk = 1.43 from Cp = 0.29 and Cpk = 0.18, as well as an increase in RFT percentage of 5.78% or to 81.62% over the last two months.

Model Optimasi Perancangan Jaringan Rantai Pasok Biomassa dari Tandan Kosong Kelapa Sawit di Sumatera Barat Imansuri, Febriza; Hadiguna, Rika Ampuh; Afrinaldi, Feri
Jurnal Optimasi Sistem Industri Vol. 18 No. 1 (2019): Published April 2019
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.v18.n1.p1-13.2019

West Sumatra has great potential in developing biomass based on palm oil waste. This is because the largest plantation production in West Sumatra comes from the oil palm commodity of 1,082,820 tons in 2014. Therefore, it is necessary to design a model of supply chain biomass network for the distribution of Empty Fruit Bunches (EFB) from CPO factory suppliers located in West Sumatra and distributed to Depot Pertamina Teluk Kabung. Stages performed in the implementation of this study began with a preliminary study to determine the potential of biomass in West Sumatra. Furthermore, the design of chain supply chain optimization model by identifying supply chain activity, knowing the characteristics of supply chain system and make the formulation of mathematical model. The design of supply chain biomass from Empty Fruit Bunches (EFB) in West Sumatera, starting from raw material Tandan Kosong Kelapa Sawit (TKKS) sourced from Crude Palm Oil (CPO) factory in West Pasaman Regency and surrounding. This is because Pasaman Barat Regency is the central agroindustry of oil palm plantation which has 17 most palm oil factories in West Sumatra. The potential of bioethanol derived from CPO waste can be done by establishing bioethanol plant located with the same CPO factory so that it is adjacent to the source of the raw material. The result of the mathematical model mixed integer linear programming is placement of bioethanol plant location at PT Pasaman Marama Sejahtera with medium scale and total cost of IDR 251,563,700,000.00.

Optimal PLA+ 3D Printing Parameters through Charpy Impact Testing: A Response Surface Methodology Engelbert Harsandi Erik Suryadarma; Pringgo Widyo Laksono; Ilham Priadythama
Jurnal Optimasi Sistem Industri Vol. 23 No. 1 (2024): Published in July 2024
Publisher : The Industrial Engineering Department of Engineering Faculty at Universitas Andalas

Additive manufacturing (AM) has revolutionized the manufacturing sector, particularly with the advent of 3D printing technology, which allows for the creation of customized, cost-effective, and waste-free products. However, concerns about the strength and reliability of 3D-printed products persist. This study focuses on the impact of three crucial variables—infill density, printing speed, and infill pattern—on the strength of PLA+ 3D-printed products. Our goal is to optimize these parameters to enhance product strength without compromising efficiency. We employed Charpy impact testing and Response Surface Methodology (RSM) to analyze the effects of these variables in combination. Charpy impact testing provides a measure of material toughness, while RSM allows for the optimization of multiple interacting factors. Our experimental design included varying the infill density from low to high values, adjusting printing speeds from 70mm/s to 100mm/s, and using different infill patterns such as cubic and others. Our results show that increasing infill density significantly boosts product strength but also requires more material and longer processing times. Notably, we found that when the infill density exceeds 50%, the printing speed can be increased to 100mm/s without a notable reduction in strength, offering a balance between durability and production efficiency. Additionally, specific infill patterns like cubic provided better strength outcomes compared to others. These findings provide valuable insights for developing stronger and more efficient 3D-printed products using PLA+ materials. By optimizing these parameters, manufacturers can produce high-strength items more efficiently, thereby advancing the capabilities and applications of 3D printing technology in various industries.

Innovative Multi-Criteria Decision-Making Approach for Supplier Evaluation: Combining TLF, Fuzzy BWM, and VIKOR Ikhwan Arief; Dicky Fatrias; Ferry Jie; Armijal
Jurnal Optimasi Sistem Industri Vol. 22 No. 2 (2023): Published in December 2023
Publisher : The Industrial Engineering Department of Engineering Faculty at Universitas Andalas

When confronted with underperforming suppliers, the need to evaluate and improve supplier performance becomes apparent. However, the inherent inaccuracies in information introduce complexity, especially when subjective human judgment is involved in the supplier evaluation process. Associated with such problem, this study presents a novel methodology for supplier performance evaluation in the crumb rubber industry, integrating the Taguchi Loss Function (TLF), fuzzy Best-Worst Method (BWM), and VIKOR technique in group decision-making environment. Aimed at addressing the challenges in industries with variable supplier quality and performance, such as the crumb rubber industry in Indonesia, the methodology was empirically tested to demonstrate its practical utility. The process involved identifying evaluation criteria through literature review tailored to the needs of decision makers (DMs), applying TLF to quantify losses from supplier performance deviations, using fuzzy BWM to determine criteria weights based on the DMs judgment, and employing the VIKOR technique for comprehensive supplier ranking. The findings underscore the methodology's effectiveness in enhancing decision-making, offering a unified metric that accommodates diverse criteria and balances precise data with subjective assessments. This approach simplifies the evaluation process, particularly in situations with conflicting interests among decision-makers. Demonstrating its practical application in the crumb rubber industry, the study highlights the methodology's potential for broader industrial applicability. Future research could explore comparative analyses with other analytical methods, further establishing the methodology's robustness and adaptability in different management contexts.

Modeling Consumer Willingness to Consider Electric Motorcycles in Indonesia: A System Dynamics Approach Ahmad Rafi Adnanta; Roni Zakaria Raung; Wahyudi Sutopo; Ihwan Susila
Jurnal Optimasi Sistem Industri Vol. 24 No. 1 (2025): Published in June 2025
Publisher : The Industrial Engineering Department of Engineering Faculty at Universitas Andalas

Sustainable transport plays a key role in the fight against climate change, particularly in developing countries where reliance on conventional vehicles is high. Motorcycles account for the majority of the fleet of motor vehicles in Indonesia and contribute significantly to emissions. In order to achieve its Paris target of a 29 percent reduction of carbon emissions, the government is encouraging electric cars with various incentives. This study develops a willingness to consider (WTC) model for electric motorcycles in Indonesia based on the powertrain technology transition market agent model (PTTMAM) and utilizes Vensim software to simulate outcomes. The WTC model is built on the assumption that consumers' willingness to consider electric motorcycles is influenced by factors such as costs, marketing, and exposures. The system dynamics model consists of four modules: the conventional motorcycle, the electric motorcycle, the marketing module, and the willingness to consider module. The simulation results show an increasing trend in consumers’ willingness to consider electric motorcycles from 2017-2035, with the WTC value reaching 0.3209 in 2035. While this indicates a positive shift toward greater consumer interest in electric motorcycles, the growth remains modest and slow, reflecting the challenges of widespread adoption. Additionally, this study evaluates three government incentive and subsidy policy scenarios. The scenario results indicate that government subsidies and incentives can increase the consumers’ willingness to consider electric motorcycles in Indonesia, thereby increasing their market share. Among the scenarios, the purchase price subsidy is the most effective, as it directly reduces the financial barrier, encouraging more consumers to make the switch to electric motorcycles.

Pengembangan Model Kualitas Pelayanan Jasa Pendidikan Sekolah Karakter di Jakarta Kirana Rukmayuninda Ririh; Firda Meira Pratiwi
Jurnal Optimasi Sistem Industri Vol. 17 No. 2 (2018): Published in October 2018
Publisher : The Industrial Engineering Department of Engineering Faculty at Universitas Andalas

This study aims to investigate the correlation of service quality to customer satisfaction, loyalty, and deployment of communication using Word of Mouth (WOM). The research was conducted at Character-based School in Jakarta, involving 84 parents as respondents. A purposive sampling method was applied. The data were collected through a survey questionnaire. The measurement was using a four-scale Likert. The analysis was supported by SEM (Structural Equation Modeling) which the tool was SmartPLS version 3.0. As results show that there were three significant relationships which between customer loyalty and Word of Mouth (0.691), service quality and customer satisfaction (0.298), also service quality and customer loyalty (0.340). It depicted that loyal customer was more significant than satisfying one. The conclusion of this study pointed out that loyalty played role in improving and maintaining a robust marketing strategy for Character-Based School. The more customer loyalty created the stronger word of mouth throughout customer.

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Rika Ampuh Hadiguna

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hadiguna@ft.unand.ac.id

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Journal Mail Official
hadiguna@ft.unand.ac.id

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Location
Kota padang,

Sumatera barat

INDONESIA