Tedjo Sukmono
Program Studi Teknik Industri, Fakultas Sains dan Teknologi, Universitas Muhammadiyah Sidoarjo

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Forecasting Needs Of Mountain Types Of DDD Bike Using The Seasonal Autoregressive Integrated Moving Average Model Approach Didin Muhjidin; Tedjo Sukmono
Procedia of Engineering and Life Science Vol 1 No 2 (2021): Proceedings of the 2nd Seminar Nasional Sains 2021
Publisher : Universitas Muhammadiyah Sidoarjo

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (819.265 KB) | DOI: 10.21070/pels.v1i2.1002

Abstract

One of the bicycle manufacturers in Indonesia, namely PT. DDD is a manufacture engaged in the production of various types of bicycles with a make to stock production system. Market demand that fluctuates every year results in a lack of readiness to meet market needs. So a re-planning is needed in order to meet all market demands. The Box Jenkins statistical method, the Seasonal Autoregressive Integrated Moving Average model, is one of the appropriate approaches to solve problems at PT. DDD. The advantages of the SARIMA model can be used to forecast seasonal or non-seasonal time series simultaneously. The best SARIMA model approach to forecasting demand for mountain bikes at PT. DDD is SARIMA (0,0,0)(0,1,1)12 with the equation Zt=Zt-12+ΘQat-12+at with the smallest MAPE value of 32.35%. So that the model is said to be feasible to predict mountain bikes and the model can predict up to 12 periods in 2021.
OPTIMALISASI PENENTUAN BIAYA MINIMUM PADA PENGENDALIAN PERSEDIAAN BAHAN BAKU DENGAN MENGGUNAKAN METODE DYNAMIC PROGRAMMING (STUDI KASUS DI PT. XYZ) Vivin Nur Oktavianty; Tedjo Sukmono
Spektrum Industri Vol. 18 No. 1: April 2020
Publisher : Universitas Ahmad Dahlan Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12928/si.v18i1.10972

Abstract

PT. XYZ is a manufacturing company that produces semi-finished goods, that is imitation leather (PVC). This company has inventory problem in their production process, that is raw material shortages.  The purpose of this study was to determine the amount of calcium carbonate raw materials purchased by PT. XYZ with optimal costs. Before using this Dynamic Programming, the cost of buying raw materials is Rp. 7,345,000,000. From the results of planning the purchase of raw materials for the next 12 periods (January-December 2018) are 1184, 1185.5, 1187.1, 1188.6, 1190.1, 1191.6, 1193.2, 1194.7, 1196.2, 1197.7, 1199.3 and 1200.8 Tons. To compile a production plan by minimizing total production costs, the dynamic programming method is used with the objective function Min Fn(In) = . As a result, the total purchase cost of calcium carbonate raw material is a minimum of Rp. 7,154,355,000. After calculating the cost, it can be seen that after using the dynamic programming method the profits obtained by the company Rp. 114,472,000 compared to before using the dynamic programming method Rp. 111,040,000.