Jurnal Optimasi Sistem Industri
ISSN / EISSN : 2088-4842 / 2442-8795
Published by: Universitas Andalas (10.25077)
Total articles ≅ 194
Latest articles in this journal
Jurnal Optimasi Sistem Industri, Volume 20, pp 11-21; https://doi.org/10.25077/josi.v20.n1.p11-21.2021
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.
Jurnal Optimasi Sistem Industri, Volume 20, pp 33-41; https://doi.org/10.25077/josi.v20.n1.p33-41.2021
The waste bank is one of the methods used by the Government of Sleman Regency, DIY, to solve the waste problem. However, citizen participation to be active as customers in the waste bank is still lacking. For this reason, a study was conducted to find out what factors affect the level of activity of citizens in depositing waste into the waste bank. The research uses The Theory of Planned Behavior, coupled with factors: knowledge of how and what and knowledge of consequences. Data was collected through interviews with several bank administrators and customers and filling out the questionnaire. Respondents were selected by purposive sampling from 11 waste banks. The analysis method uses multiple linear regression by testing the significance of the regression model, the coefficient of determination, and the partial effect test of each variable. The results showed that attitudes, subjective norms, contr, knowledge of how and what, and knowledge of consequences simultaneously affected 73% of the intention. Among the five independent variables, only the perceived behavioral control has no partial effect. The study also showed that the intention had a significant effect on the waste bank's active behavior with a coefficient of determination of 63%.
Jurnal Optimasi Sistem Industri, Volume 20, pp 42-51; https://doi.org/10.25077/josi.v20.n1.p42-51.2021
COVID-19 pandemic has become an international concern. Policies to prevent the spread of disease, such as learning from home, are applied to university students. The present study examines the risk assessment in relation to physical, mental, and psychosocial condition of Indonesian students toward COVID-19 and learning from home. This study involves 838 Indonesian students. A questionnaire consisting of demographic data and constructs from a comprehensive literature study regarding COVID-19 related issues and learning from home issues was developed. Most Indonesian student respondents have a good knowledge of COVID-19 and have received accurate information from the government. The anxiety level during COVID-19 is mild. In relation to physical condition, most students reported musculoskeletal symptoms in the neck, shoulder, and back areas. The respondents conduct preventive behavior against COVID-19 spread, with lack of physical exercise. In relation to mental and psychosocial condition. In relation to mental and psychosocial condition, respondents report moderate mental workload and proper social support from lecturers and friends. In conclusion, most Indonesian university students have a good knowledge and proper attitudes toward COVID-19 and learning from home, which are important in combating and passing through the pandemic.
Jurnal Optimasi Sistem Industri, Volume 20, pp 52-60; https://doi.org/10.25077/josi.v20.n1.p52-60.2021
This research aims to evaluate the egg-laying chicken feeder that was designed at egg-laying chicken farm small and medium enterprise (SME). The main reason of this tool design was due to the worker’s complain of feeling pain during the feeding process. Evaluation was performed based on Nordic Body Map questionnaire result, physiological workload, and NIOSH lifting equation calculation. The observed work ranged from the feed filling in the basket until all feeds were distributed. The results showed that the %CVL was in the range of 18%-30% and the energy consumption of workers was in the range of 1.24-3.00 Kcal/minute. Thus, physiologically, the work activities carried out by the feed workers were categorized as very light workload. Meanwhile, evaluation using Lifting Index (LI) methods in the process of feeding showed the LI value ranged from 0.9-1, therefore this activity is safe to perform manually. Based on the prototype evaluation on the feeding aid, the process of feeding activities was more effective 1.5 times faster than the old tools. In addition, with the use of this new tool, the feeding process was easier to adjust the dose each time.
Jurnal Optimasi Sistem Industri, Volume 20, pp 1-10; https://doi.org/10.25077/josi.v20.n1.p1-10.2021
The Conventional Vehicle Routing Problem (VRP) has the objective function of minimizing the total vehicles’ traveling distance. Since the fuel cost is a relatively high component of transportation costs, in this study, the objective function of VRP has been extended by considering fuel consumption minimization in the situation wherein the loading weight and traveling time are restricted. Based on these assumptions, we proposed to extend the route division procedure proposed by Kuo and Wang  such that when one of the restrictions can not be met the routing division continues to create a new sub-route to find an acceptable solution. To solve the formulated problem, the Particle Swarm Optimization (PSO) algorithm is proposed to optimize the vehicle routing plan. The proposed methodology is validated by solving the problem by taking a particular day data from a bottled drinking water distribution company. It was revealed that the saving of at best 13% can be obtained from the actual routes applied by the company.
Jurnal Optimasi Sistem Industri, Volume 20, pp 22-32; https://doi.org/10.25077/josi.v20.n1.p22-32.2021
The poor air quality of Jakarta, caused among others by fossil fuel combustion for transportation, harmfully affects the health of its people. Carbon emissions resulting from transportation activities can be reduced by getting people to use public transportation more frequently. This research aims at designing a persuasive application to encourage people to use public transportation more often. The steps of interaction design were employed. Firstly, user needs were identified using interviews, resulting in 48 interpreted needs which were then grouped into nine primary needs. Secondly, a design workshop involving users and designers was conducted to produce three concept alternatives. In the next stage, the best concept was selected using the concept scoring method and was subsequently refined through the SCAMPER method. A high-fidelity prototype was developed based on the final concept. Lastly, the evaluation process of the application prototype named ecoGlide consisted of two major parts, i.e. the evaluation of performance and persuasive qualities. The performance evaluation was conducted through Usability Testing using five criteria. The effectiveness and efficiency criteria consecutively score 91% and 71.43%, exceeding the minimum acceptable value of 70%. Furthermore, the satisfaction, usefulness, and learnability criteria respectively score 3.83, 3.88, and 3.88, which surpass the threshold value of 3.4. The persuasive quality was evaluated using the qualitative method through a coding scheme. The result shows that the Emotion and Persuasion categories were most closely related to the application use. The most influential sub-category of the persuasion aspect is Reward Driven, which ranks 4th out of 14 sub-categories. Overall, the ecoGlide application was considered to have good usability and persuasive ability.
Jurnal Optimasi Sistem Industri, Volume 20, pp 61-71; https://doi.org/10.25077/josi.v20.n1.p61-71.2021
The ever-increasing volume of municipal waste in Yogyakarta brings overload capacity problems to the Piyungan Landfill. This circumstance results in environmental pollution which harms the local residents. Therefore, this study was conducted to determine the impact of pollution in the Piyungan Landfill from an economic, environmental, and social perspective. Furthermore, this study aims to formulate a waste management strategy in the landfill using the fishbone analysis to find out the root causes of existing problems, the stakeholder analysis method to determine the role of each stakeholder involved, and the SWOT analysis method to determine potential strategies for waste management. From those analysis methods, it is concluded that there are six root causes in the landfill, namely the waste management process, the amount of waste, landfill facilities, the technology used, the implementation process, and government policies. This study recommends several waste management improvements from the combination of strengths and opportunities factors (SO Strategy). The combination of these strategies includes: (1) establishing cooperation policies with foreign parties. (S1, O1); (2) optimizing budget and waste management technology. (S2, O2); (3) providing transportation facilities and technology to optimize the recycled waste business. (S3, O2, O3); and (4) maximizing resources to optimize the recycled waste business. (S4, O3). These strategies are expected to be able to increase the capacity and capability of the Piyungan Landfill in managing waste and overcoming environmental pollution.
Jurnal Optimasi Sistem Industri, Volume 19, pp 111-121; https://doi.org/10.25077/josi.v19.n2.p111-121.2020
Waste minimization is a key success factor to achieve sustainability, including in the edible oil industry. One type of solid waste produced substantially in this industry is spent bleaching earth (SBE), which comes from a mixture of bleaching earth (BE) and activated carbon (CA) used in the edible oil refining process. SBE that is recycled through a heating process is known as heat regenerated SBE (HRSBE). The process is influenced by two factors as stated in previous studies: temperature and time. In the current study, we report the results of experiments to find the optimal combination of temperature and time in restoring the absorbent quality of SBE by observing four quality parameters: colors (red and yellow), Free Fatty Acid (FFA), and Peroxide Value (PV). The current study uses Response Surface Methodology (RSM) to design the experiments and to find the equations of the relationship between the factors for each response; as well as Goal Programming (GP) to find the most optimal combination of factors in order to achieve aggregated quality targets. The findings show that 3.414 hours of heating at a temperature of 151.64oC allow HRSBE to produce coconut oil in accordance with the expected quality targets.
Jurnal Optimasi Sistem Industri, Volume 19, pp 101-110; https://doi.org/10.25077/josi.v19.n2.p101-110.2020
Productivity is a challenge in the construction industry, commonly initiated by fragmentation. In addition, some work levels have been identified, including the micro, meso, and macro. However, the construction supply chain is one of the possible solutions adopted to increase productivity. The purpose of this study, therefore, is to develop a framework for measuring supply chain construction performance at the micro, meso, and macro levels. These respective stages are tiered from the bottom to the top level as a supply chain management concept. Furthermore, a design for the supply chain performance measurement framework is created, followed by formulation with KPI, and the consequent application in the project. Therefore, performance is evaluated based on the construction materials, as a large resource. The results identified the supply chain performance at the micro-level as the basis for possible measures between contractor and supplier, using the SCOR. However, the emphasis was made on the strength of construction companies with large suppliers at the meso level. Meanwhile, the macro-level includes the accumulation of related measurements from micro as well as meso, and are consequently used to define the relationship between construction actors at the national level.
Jurnal Optimasi Sistem Industri, Volume 19, pp 144-156; https://doi.org/10.25077/josi.v19.n2.p144-156.2020
Soybean self-sufficiency in Central Java Province is a problem that is difficult to realize at this time. As an important commodity, self-sufficiency becomes a serious concern for the government. Supply chain management of soybean is related to the integration of supply, demand, and distribution of soybean. The characteristics of entities involved in the soybean supply chain are complex, dynamic, and probabilistic that make the problem cannot be solved using an analytical model and it becomes too risky for trial and error. A suitable tool is using a simulation model. This paper deals with developing a Decision Support System (DSS) using a simulation model that will assist the government in adopting policies in order to achieve self-sufficiency of soybean and the improvement of farmer's welfare. DSS will help decision-makers to try various scenarios of policy in an easy way. The method was started with developing model components, then decision components, and next creating user interfaces. The simulation and system modeling is created by using Powersim software with the intent to obtain the simulation and single document interface (SDI) of the supply chain model. The result shows that land expansion policy is a top priority for realizing food self-sufficiency while increasing productivity and reducing costs of agricultural activities are the main priorities for improving the welfare of farmers.