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All Journal Jurnal Riset danAplikasi Teknik Industri (JRATI) Serambi Engineering
Herdiana, Mochamad Rafi
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Control & Systems Engineering Decision Sciences, Operations Research & Management Earth & Planetary Sciences Energy Engineering Environmental Science Industrial & Manufacturing Engineering

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Lever Assy Product Distribution Needs Planning with the Distribution Requirement Planning Method in the Automotive Industry Herdiana, Mochamad Rafi; Herwanto, Dene
Jurnal Serambi Engineering Vol. 10 No. 2 (2025): April 2025
Publisher : Faculty of Engineering, Universitas Serambi Mekkah

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Abstract

The market demand to get quality products is not enough to be answered only by the company's ability to provide the requested products, the company's ability to fulfill order stock, low prices, order time targets, and marketing capabilities. Planning for product availability and distribution processes is also needed to meet consumer needs. PT XYZ is a company engaged in the automotive sector as a supplier. The problem that occurs is that there is an over cost distribution so that the company has to increase costs for the distribution of Lever Assy products. One of the reasons that allegedly caused the problem was because the forecasting that became the basis for the company to take policies in the distribution process of the Lever Assy product was not done properly. The goal to be achieved in this study is to plan distribution needs by considering the demand aspect to avoid over cost distribution. The results of this study show that the total cost incurred based on the company method is Rp71,614,500, while using the distribution requirement planning method is Rp52,864,500, which means that there is a savings of Rp.18,750,000 with a percentage of 26%.
Marketing Strategy Determination Using Markov Chain and Game Theory: A Case Study of Ready-to-Drink Tea Products Herdiana, Mochamad Rafi; Dewi, Yulida Intani; Ikatrinasari, Zulfa Fitri; Amrina, Uly
Jurnal Serambi Engineering Vol. 10 No. 3 (2025): Juli 2025
Publisher : Faculty of Engineering, Universitas Serambi Mekkah

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Abstract

Decrease in the number of demand in the market and the transfer of consumers from the Nuu Green Tea brand to the Pucuk Harum Tea brand or vice versa is a result that can occur from market share competition. The calculation results obtained after doing manual calculations using the Markov chain method are the probability of transferring the subscription from each product a few times ago, at this time, and the time to come. For the time to come alone based on the steady state obtained is in the 10th year period. With the probability value of the movement from the shoot tea to Nuu Green Tea is 0.413 for a period some time ago and at this time, for other products transfer can be seen in Figure IV.6. For the value of the steady state in the 10th iteration with the mastery of the shoots of the market share of 0.4158 or 41.58% and Nuu Green Tea controlled the market share of 0.5841 or 58.41%.  The calculation results that have been done manually and the use of application assistance can be concluded that the use of the maximin-minimax method produces an optimum solution, namely on X1 for row players (The Pucuk), and Y1 for column players (Nuu Green Tea). With a game value of 32. then the best marketing strategy used by Teh pucuk and Nuu Green Tea is the attribute 'flavor variant' by utilizing the flavor variant of the two can compete in the flavor variant.
Peningkatan Kapasitas Mesin Rubber Sheet Calendar Menggunakan Discrete Event Simulation: Studi Kasus di Industri Pengolahan Karet Herdiana, Mochamad Rafi; Elfantoro, Indra; Dewi, Yulida Intani; Kurniawan, Indra
JURNAL RISET DAN APLIKASI TEKNIK INDUSTRI Vol. 3 No. 01 (2025): Volume 03 Issue 01, Agustus 2025
Publisher : Study Program of Industrial Engineering, Udayana University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24843/JRATI.2025.v03.i01.p11

Abstract

Increasing production capacity is one of the key strategies to maintain the competitiveness of tire companies in an increasingly dynamic and competitive market. One of the critical machines in the tire production process is the Rubber Sheet Calender, which currently has a capacity of only 2700 Tires Per Day (TPD). However, based on the sales forecast for 2025, the required production capacity is expected to reach 3000 TPD. This study aims to analyze and enhance the capacity of the Rubber Sheet Calender machine using the Discrete Event Simulation (DES) approach. Data were collected through direct observation, time studies, and interviews with machine operators and production supervisors. A simulation model was developed to represent the actual condition (as-is), and improvement scenarios were tested, including adding labor, increasing buffer capacity, and reducing setup time. The simulation results show that a combination of improvements can significantly increase throughput by increasing machine speed from 4.65 to 6.31 (a 36% increase) and raising production capacity from 3360 to 4962 (a 59% increase). Thus, the improvement recommendations using DES have proven to be an effective decision-support tool for enhancing production capacity.
Optimasi Peramalan Penjualan Perishable Product dengan Metode Time Series Menggunakan Software POM-QM Dewi, Yulida Intani; Herdiana, Mochamad Rafi; Hernadewita
JURNAL RISET DAN APLIKASI TEKNIK INDUSTRI Vol. 3 No. 01 (2025): Volume 03 Issue 01, Agustus 2025
Publisher : Study Program of Industrial Engineering, Udayana University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24843/JRATI.2025.v03.i01.p10

Abstract

Perishable products are items with short shelf life. In this study, perishable product being analyzed has only one day shelf life. Therefore, an accurate forecast method is needed to avoid shortage and waste. Shortage occurs whend demand exceeds the company’s stock, resulting potential loss sales. Waste occurs when demand is lower than available stock, leading to overstock. Excexx inventory causing losses and reduces profit. This study is conducted using 2 scenarios, as shown in Table 1. Scenario 1 uses 60 days od data, while scenario 2 separates data between weekend and weekdays. Data abalysis was performed using time series method with POM-QM software. The best method is determined based on lower MAD, MSE, MAPE. The result of this study sho that separating the historical data between weekends and weekdays (scenario 2) leads to better forecasting accuracy, indicated by a lower MAPE compared to scenario 1. For weekend forecasting, the best method is exponential smoothing (Scenario 2A.2) with MAPE 10,05%. For weekday forecasting, the best method is moving average (Scenario 2B.1) with MAPE 15,40%. The research is expected to serve as a reference for company in selecting appropriate forecasting method. The goal is to help company anticipate shortage and waste in perishable products. The recommendation for company is automate the separation of weekend and weekday data to accelerate the forecasting prosess. Future research recommendation is use other forecast method and software, then consider factor consists of shelf life, promotion, national holidays, or national event.
Inventory Management Optimization of Snack to Minimize Days Sales Inventory (DSI) and Total Cost Dewi, Yulida Intani; Elfantoro, Indra; Herdiana, Mochamad Rafi; Ikatrinasari, Zulfa Fitri
Jurnal Serambi Engineering Vol. 11 No. 1 (2026): Januari 2026
Publisher : Faculty of Engineering, Universitas Serambi Mekkah

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Abstract

This study aims to optimize inventory control for snack products in the retail industry, characterized by highly fluctuating demand and elevated Days Sales Inventory (DSI) levels. Focusing on Class A products with high DSI offers the greatest potential impact on inventory management efficiency. The approach integrates Holt-Winters forecasting, ARIMA (1,1,1), and Random Forest Regression with quantitative models such as Economic Order Quantity (EOQ) and Periodic Order Quantity (POQ), as well as stock control techniques including Safety Stock and Reorder Point, to determine the optimal order quantity and ordering time. Sales data for 21 weeks were processed to generate sales forecasts for the subsequent 31 weeks, covering weeks 22 through 52, using all three forecasting methods. The evaluation metrics indicate that Random Forest Regression achieved the best performance, with a Mean Absolute Error (MAE) of 42.4, Mean Absolute Percentage Error (MAPE) of 13.9%, and a Root Mean Squared Error (RMSE) of 46.7, The results show a significant reduction in DSI and total costs, contributing positively to strengthening the company’s cash flow. Further analysis over the 31-week period using the POQ method resulted in a decrease in DSI from the actual level of 111 days to 71 days, and also reduction in total cost from IDR 14.933.114 to IDR 10.104.863, representing a difference of IDR 4.828.250. In addition to the integrated forecasting and EOQ–POQ methods, it is recommended to enhance the adaptation of dynamic forecasting models that are more responsive to changes in demand patterns and to develop real-time monitoring systems using ERP or IoT technology to minimize the risks of stockouts and product spoilage. This research provides both practical and academic contributions toward achieving more efficient and sustainable inventory management for snack products. 
Co-Authors Dene Herwanto Dewi, Yulida Intani Elfantoro, Indra Hernadewita Indra Kurniawan Uly Amrina Zulfa Fitri Ikatrinasari