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Probabilistic Programming with Piecewise Objective Function for Solving Supplier Selection Problem with Price Discount and Probabilistic Demand Sutrisno, Sutrisno; Sunarsih, Sunarsih; Widowati, Widowati
Proceeding of the Electrical Engineering Computer Science and Informatics Vol 7, No 2: EECSI 2020
Publisher : IAES Indonesia Section

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/eecsi.v7.2038

Abstract

In this article, a supplier selection problem with price discount and probabilistic demand was solved by formulating a new probabilistic programming model with a piecewise objective function. The proposed model was able to be used by the decision-maker to calculate the optimal decision involving the appropriate raw material quantity to be ordered from each supplier to have minimal total procurement cost. A numerical experiment was conducted with some randomly generated data and the results showed the supplier selection problem was solved by the proposed model and the optimal decision value is achieved.
Probabilistic Programming with Piecewise Objective Function for Solving Supplier Selection Problem with Price Discount and Probabilistic Demand Sutrisno Sutrisno; Sunarsih Sunarsih; Widowati Widowati
Proceeding of the Electrical Engineering Computer Science and Informatics Vol 7, No 2: EECSI 2020
Publisher : IAES Indonesia Section

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/eecsi.v7.2038

Abstract

In this article, a supplier selection problem with price discount and probabilistic demand was solved by formulating a new probabilistic programming model with a piecewise objective function. The proposed model was able to be used by the decision-maker to calculate the optimal decision involving the appropriate raw material quantity to be ordered from each supplier to have minimal total procurement cost. A numerical experiment was conducted with some randomly generated data and the results showed the supplier selection problem was solved by the proposed model and the optimal decision value is achieved.
Joint Decision on Integrated Supplier Selection and Stock Control of Inventory System Considering Purchase Discount Widowati Widowati; Sutrisno Sutrisno; R. Heru Tjahjana
International Journal of Supply Chain Management Vol 6, No 4 (2017): International Journal of Supply Chain Management (IJSCM)
Publisher : International Journal of Supply Chain Management

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (13.161 KB)

Abstract

Stock control and supplier selection are two vital parts on supply chain and management. Integrating these parts by solving them simultaneously is a good idea for cost reducing. Furthermore, if some suppliers give a purchase discount for their product, how to determine the optimal strategy is interesting. In this paper, we propose a mathematical model in a mixed integer quadratic programming with piecewise objective function to determine the optimal strategy for integrated supplier selection and stock control of multiproduct inventory system considering purchase discount. This stock control refers to bring the stock level of each product to a reference level given by decision maker. We formulate the model in two environments which are deterministic where all parameters are known and stochastic where the demand is random. Two numerical experiments are performed to evaluate the model. From the results, the optimal strategy was generated i.e. the optimal product volume purchased from each supplier and the stock level of each product follows the reference level.
Control of inventory system with random demand and product damage during delivery using the linear quadratic gaussian method Sutrisno Sutrisno; Widowati Widowati; R. Heru Tjahjana
Indonesian Journal of Electrical Engineering and Computer Science Vol 22, No 3: June 2021
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijeecs.v22.i3.pp1748-1753

Abstract

This study formulates a dynamical system for the control of a single product inventory system in accordance with the random value of demand and the percentage of damaged product during the delivery process. The formulated model has the form of a linear state-space system comprising of two disturbances, which represents the random value of demand and the percentage of the damaged product during delivery. The optimal value of the product amount ordered to the supplier is properly calculated by using the linear quadratic gaussian (LQG) method. The controller is used by the manager to make inventory level decisions under the uncertainty of demand and damaged items during the product delivery process. The result showed that the optimal product order for each review time was achieved, and the inventory level was used to obtain the right set point properly. Moreover, based on comparison with other research results, the proposed model was well performed.
HASIL PERBANDINGAN METODE IMPROVED NEWTON-RAPHSON BERBASIS DEKOMPOSISI ADOMIAN DAN BEBERAPA METODE KLASIK PADA MASALAH PERSAMAAN NON-LINIER Indah Jumawanti; Sutrisno Sutrisno; Bayu Surarso
Journal of Fundamental Mathematics and Applications (JFMA) Vol 1, No 1 (2018)
Publisher : Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (202.819 KB) | DOI: 10.14710/jfma.v1i1.8

Abstract

In this paper, we work with ten nonlinear equations to compare a new method in nonlinear equation solving, Improved Newton-Raphson based on Adomian Decomposition method (INR-ADM) that consisting of two types called INR-ADM 1 and INR-ADM 2. The difference between INR-ADM 1 and INR-ADM 2 is on the iteration formula form. From our results, it was showed that INR-ADM 1 and INR-ADM 2 are not always better than classic Newton-Raphson method in term of the iteration number. However, if INR-ADM 1 and INR-ADM 2 are compared to Regula False method and Secant method, they are always better i.e. they had fewer number of iteration. The INR-ADM 1 and INR-ADM 2 had shorter computational time than Regula False method. Furthermore, the computational time of INR-ADM 1 and INR-ADM 2 cannot be claimed that they had shorter or longer if they are compared to Newton-Raphson method and Secant method.
IMPLEMENTASI LOGIKA FUZZY MAMDANI UNTUK MENENTUKAN KOMPOSISI OPTIMAL PUPUK ORGANIK DAN ANORGANIK NPK PADA TANAMAN MENTIMUN Fajar Ridwan Analistyawan; Sutrisno Sutrisno; Solichin Zaki
Journal of Fundamental Mathematics and Applications (JFMA) Vol 1, No 2 (2018)
Publisher : Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (2794.798 KB) | DOI: 10.14710/jfma.v1i2.20

Abstract

In this article, we have determined the optimal composition of organic fertilizer and NPK inorganic fertilizer for cucumber plants. We have formulated two fuzzy systems which are fuzzy system 1 and fuzzy system 2. The inputs for fuzzy system 1 are plants’ height and the number of leaves where the output is the growth rate. Fuzzy system 2 had input of growth rate and NPK concentration and output of organic fertilizer concentration. By processing the data using fuzzy system, we have compared the cucumber plant with organic fertilizer and NPK to cucumber plant that was used only NPK fertilizer. The result had shown that the cucumber plant with organic fertilizer and NPK was produced the better outcome than the cucumber plants with NPK only.
MODELING PREDICTIVE TRACKING CONTROL FOR MAX-PLUS LINEAR SYSTEMS IN MANUFACTURING Lathifatul Aulia; Widowati Widowati; R. Heru Tjahjana; Sutrisno Sutrisno
Journal of Fundamental Mathematics and Applications (JFMA) Vol 3, No 2 (2020)
Publisher : Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (491.691 KB) | DOI: 10.14710/jfma.v3i2.8605

Abstract

Discrete event systems, also known as DES, are class of system that can be applied to systems having an event that occurred instantaneously and may change the state. It can also be said that a discrete event system occurs under certain conditions for a certain period because of the network that describes the process flow or sequence of events. Discrete event systems belong to class of nonlinear systems in classical algebra. Based on this situation, it is necessary to do some treatments, one of which is linearization process. In the other hand, a Max-Plus Linear system is known as a system that produces linear models. This system is a development of a discrete event system that contains synchronization when it is modeled in Max-Plus Algebra. This paper discusses the production system model in manufacturing industries where the model pays the attention into the process flow or sequence of events at each time step. In particular, Model Predictive Control (MPC) is a popular control design method used in many fields including manufacturing systems. MPC for Max-Plus-Linear Systems is used here as the approach that can be used to model the optimal input and output sequences of discrete event systems. The main advantage of MPC is its ability to provide certain constraints on the input and output control signals. While deciding the optimal control value, a cost criterion is minimized by determining the optimal time in the production system that modeled as a Max-Plus Linear (MPL) system. A numerical experiment is performed in the end of this paper for tracking control purposes of a production system. The results were good that is the controlled system showed a good performance.
PENGEMBANGAN MODEL EPIDEMIK SIRA UNTUK PENYEBARAN VIRUS PADA JARINGAN KOMPUTER Panca Putra Pemungkas; Sutrisno Sutrisno; Sunarsih Sunarsih
Journal of Fundamental Mathematics and Applications (JFMA) Vol 2, No 1 (2019)
Publisher : Diponegoro University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (299.114 KB) | DOI: 10.14710/jfma.v2i1.26

Abstract

This paper is addressed to discuss the development of epidemic model of SIRA (Susceptible-Infected-Removed-Antidotal) for virus spread analysis purposes on a computer network. We have developed the existing model by adding a possibility of antidotal computer returned to susceptible computer. Based on the results, there are two virus-free equilibrium points and one endemic equilibrium point. These equilibrium points were analyzed for stability issues using basic reproduction number and Routh-Hurwitz Method.
PENINGKATAN PRODUKTIVITAS INDUSTRI GULA SEMUT MELALUI PENGEMBANGAN PROSES PEMASAKAN NIRA AREN DAN PENGERINGAN GULA SEMUT Didik Ariwibowo; Sutrisno Sutrisno; Mohammad Endy Yulianto
Jurnal Pengabdian Vokasi Vol 1, No 2 (2019): Nopember 2019
Publisher : Sekolah Vokasi Universitas Diponegoro

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (310.778 KB)

Abstract

Paper ini mengulas kegiatan menerap-kembangkan teknologi tepat guna pemasak nira aren dan oven pengering gula semut untuk meningkatkan produktivitas IKM berbasis nira aren. Tahapan kegiatan meliputi: (i) desain dan pabrikasi prototipe evaporator-uv tipe agitated film kapasitas 25 kg/batch dan oven pengering gula semut, dan (ii) analisis tekno-ekonomi. Prototipe telah memenuhi uji fungsional dan uji penerapan. Hasil uji tersebut memperlihatkan bahwa alat dapat difungsikan sesuai spesifikasi desainnya. Sedangkan hasil analisis tekno-ekonomi menyatakan bahwa dengan investasi oven pengering gula semut dan pemasak nira akan menguntungkan pada harga gula semut Rp. 50.000,-/kg dan harga gula cetak Rp. 18.000,-/kg dengan jumlah penjualan minimum gula semut 900 kg/tahun dan gula cetak 1.800 kg/tahun. Jumlah penjualan tersebut dapat ditingkatkan karena kapasitas terpasang alat adalah 3 kali dari analisis produksi. Dengan kapasitas tersebut, jumlah tenaga kerja produksi minimum (pemasakan nira, pencetakan, dan produksi gula semut) adalah 5 orang
INTRODUKSI TEKNOLOGI ROASTING UNTUK MENINGKATKAN PRODUKTIVITAS INDUSTRI KOPI ROBUSTA GUNUNG KELIR Didik Ariwibowo; Sutrisno Sutrisno; Seno Darmanto; Juli Mrihardjono; Mohammad Endy Yulianto; Riana Sitawati
Jurnal Pengabdian Vokasi Vol 1, No 4 (2020): Nopember 2020
Publisher : Sekolah Vokasi Universitas Diponegoro

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (342.801 KB) | DOI: 10.14710/jpv.2020.9239

Abstract

Program for regional superior product (PPUD-DIKTI) year 2020 aims to increase income of coffee farmers who incorporated in Rahayu IV Gunung Kelir by introduction of roaster. This introduction was done by considering that the farmers was potentially developed from coffee bean to coffee powder producers. PPUD was conducted by Teams from LPPM UNDIP. The program was excecuted in steps: i) designing of roaster machine, ii) roaster machine fabrication, iii) implementation, and iv) evaluation. Program evaluation was performed by analyzing to income added from farmers. Roaster was designed dan fabricated with capacity of 3 kg/batch and processing time of 15-20 minutes. After program implementation, the farmers roasted coffee bean by themselves. Therefore, there was a different value between outsider service-roasting, that done before, and self-roasting of Rp. 10.000,-. Besides self-roasting, the farmers commercialize the roaster as roasting services with rates Rp. 15.000,; per kilograms. Result of this PPUD program shows that during 1 month, the farmers earned Rp. 4.250.000,-. This predicted that the earning would increase 4 times because of the roaster operated in 0,25 off capacity by now. This prediction based on a calculation of roaster operating in 20 days and 7 hours effective time per day.