Suprayogi Suprayogi
Institut Teknologi Bandung, Bandung

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Teknik Relaksasi Lagrange untuk Penjadwalan Pekerjaan Majemuk dengan Penggunaan Sumberdaya Simultan Suprayogi Suprayogi; Valentine Valentine
Jurnal Teknik Industri Vol. 17 No. 2 (2015): DECEMBER 2015
Publisher : Institute of Research and Community Outreach - Petra Christian University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (425.416 KB) | DOI: 10.9744/jti.17.2.71-80

Abstract

This paper discusses the multiple jobs scheduling problem with simultaneous resources. The problem involves one or more jobs with each job consist of a set of operations. Each operation is performed by more than one resource simultaneously. Number of units of each resource used for performing an operation is one or more units. The problem deals with determining a schedule of operations minimizing total weighted tardiness. In this paper, solution techniques based on Lagrangian relaxation are proposed. In general, the Lagrangian relaxation technique consists of three parts run iteratively, i.e., (1) solving individual job problems, (2) obtaining a feasible solution, and (3) solving a Lagrangian dual problem. For solving the individual job problems, two approaches are applied, i.e., enumeration and dynamic program¬ming. In this paper, the Lagrangian relaxation technique using the enumeration and dynamic programming approaches are called RL1 and RL2, respectively. The solution techniques proposed are examined using a set of hypothetical instances. Numerical experiments are carried out to compare the performance of RL1, RL2, and two others solution techniques (optimal and genetic algorithm techniques). Numerical experiments show that RL2 is more efficient than RL1. In terms of the solution quality, it is shown that RL2 gives same results compared to the optimal technique and genetic algorithm. However, both RL2 and genetic algorithm can handle larger problems efficiently.
Model Optimisasi untuk Penjadwalan Ulang Perjalanan Kereta Api Suprayogi Suprayogi; Hery Ramdhani
Jurnal Teknik Industri Vol. 17 No. 2 (2015): DECEMBER 2015
Publisher : Institute of Research and Community Outreach - Petra Christian University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (725.327 KB) | DOI: 10.9744/jti.17.2.97-104

Abstract

This paper discusses the train rescheduling problem due to disturbances. The train rescheduling problem discussed in this paper is taken from a real train network of DAOP II Bandung in Jawa, Indonesia. The train network consists of block sections including unidirectional double-tracks and bidirectional single-tracks. There are some connections among trains because they use same rolling stocks. A mixed integer linear programming model is formulated to represent the problem. Main decision variables of the model are new departure and arrival times due to the disturbance. The objective function to be minimized is the total weighted delay. The model is examined using a hypothetical instance for four disturbance cases. Numerical experiments show that the model can represent the problem under study
Genetic Algorithm for Solving Location Problem in a Supply Chain Network with Inbound and Outbound Product Flows Suprayogi Suprayogi; Senator Nur Bahagia; Yudi Thaddeus
Jurnal Teknik Industri Vol. 18 No. 2 (2016): DECEMBER 2016
Publisher : Institute of Research and Community Outreach - Petra Christian University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (583.942 KB) | DOI: 10.9744/jti.18.2.129-136

Abstract

This paper considers a location problem in a supply chain network. The problem addressed in this paper is motivated by an initiative to develop an efficient supply chain network for supporting the agricultural activities. The supply chain network consists of regions, warehouses, distribution centers, plants, and markets. The products include a set of inbound products and a set of outbound products. In this paper, definitions of the inbound and outbound products are seen from the region’s point of view.  The inbound product is the product demanded by regions and produced by plants which flows on a sequence of the following entities: plants, distribution centers, warehouses, and regions. The outbound product is the product demanded by markets and produced by regions and it flows on a sequence of the following entities: regions, warehouses, and markets. The problem deals with determining locations of the warehouses and the distribution centers to be opened and shipment quantities associated with all links on the network that minimizes the total cost. The problem can be considered as a strategic supply chain network problem. A solution approach based on genetic algorithm (GA) is proposed. The proposed GA is examined using hypothetical instances and its results are compared to the solution obtained by solving the mixed integer linear programming (MILP) model. The comparison shows that there is a small gap (0.23%, on average) between the proposed GA and MILP model in terms of the total cost. The proposed GA consistently provides solutions with least total cost. In terms of total cost, based on the experiment, it is demonstrated that coefficients of variation are closed to 0.
Algoritma Genetika untuk Pemecahan Masalah Rute Kendaraan dengan Ukuran dan Campuran Armada, Trip Majemuk, Pengiriman Terbagi, Produk Majemuk, dan Kendaraan dengan Kompartemen Majemuk Suprayogi Suprayogi; Daniel Bunga Paillin
Jurnal Teknik Industri Vol. 19 No. 2 (2017): Desember 2017
Publisher : Institute of Research and Community Outreach - Petra Christian University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (649.385 KB) | DOI: 10.9744/jti.19.2.115-124

Abstract

This paper discusses a variant of the basic vehicle routing problem (VRP) by including the following characteristics: fleet size and mix, multiple trips, split delivery, and multiple compartments. One of real cases of this problem is related to determining tanker’s routes in delivering fuel products from a supply port to a number of destination ports. Each tanker has several compartments where each compartment is dedicated to a certain fuel product. In this paper, a solution approach based on genetic algorithm (GA) is proposed and tested using nine hypothetical instances. Experiment results show that the proposed GA gives consistent results measured by coefficient variations
Tabu Search for the Vehicle Routing Problem with Multiple Trips, Time Windows, and Simultaneous Delivery-Pickup Suprayogi Suprayogi; Yusuf Priyandari
Jurnal Teknik Industri Vol. 19 No. 2 (2017): Desember 2017
Publisher : Institute of Research and Community Outreach - Petra Christian University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (330.633 KB) | DOI: 10.9744/jti.19.2.75-82

Abstract

This paper discusses a vehicle routing problem with multiple trips, time windows, and simultaneous delivery-pickup (VRPMTTWSDP). This problem is a variant of the basic vehicle routing problem (VRP) including the following characteristics: multiple trips, time windows, and simultaneous delivery-pickup.  In this paper, a solution approach based on tabu search (TS) is proposed. In the proposed TS, the sequential insertion (SI) algorithm is used to construct an initial solution. A neighbor structure is generated by applying an operator order consisting of eleven operators of relocation, exchange, and crossover operators. A tabu solution code (TSC) method is applied as a tabu restriction mechanism. Computational experiments are carried out to examine the performance of the proposed TS using hypothetical instances. The performance of the proposed TS is compared to the local search (LS) and the genetic algorithm (GA). The comparison shows that the proposed TS is better in terms of the objective function value.