Judul: Genetic Algorithm on Solving Travelling Salesman Problems for Distribution of Organic Porridge Products
Abstrak: Pada penelitian ini, dibahas pencarian rute terpendek untuk mendistribusikan produk bubur organik yang diproduksi oleh PT. Rofindiya Ekamulia Sukses ke sejumlah outlet, yang mana setiap outlet hanya dapat dikunjungi satu kali saja dan proses distribusi dimulai dan diakhiri dari suatu outlet yang sama. Terdapat 44 outlet yang pada awalnya terbagi ke dalam 9 jalur distribusi, yang kemudian penulis usulkan dikelompokkan menjadi 3 jalur distribusi saja untuk efisiensi perusahaan. Permasalahan pendistribusian produk tersebut pada masing-masing jalur distribusi dapat dikategorikan sebagai travelling salesman problems (TSP). Pencarian rute terpendek pada masing-masing jalur distribusi dilakukan dengan menggunakan algoritme genetika (GA). Dalam implementasi GA, barisan outlet pada suatu jalur distribusi direpresentasikan sebagai barisan gen pada suatu kromosom. Nilai fitness pada GA dalam hal ini diasosiasikan sebagai total jarak tempuh suatu rute, sehingga implementasi GA dalam penelitian ini diarahkan untuk memperoleh nilai fitness yang terkecil. Hasil implementasi GA menunjukkan adanya perbaikan total jarak tempuh bila jumlah iterasi dan ukuran populasi ditingkatkan. Implementasi GA dilakukan dengan menggunakan bahasa pemrograman Octave., This study discussed finding a shortest route to distribute the organic porridge products produced by PT. Rofindiya Ekamulia Sukses to some outlets, in which each outlet is visited exactly once and the distribution process is started and ended from the same outlet. There are 44 outlets involved in this study. The outlets are initially grouped into 9 distribution tracks. The authors proposed to regroup them into 3 distribution tracks to increase distribution efficiency. The distribution problem on each track can be categorized as a travelling salesman problems (TSP). Each of those 3 distribution problems is solved using genetic algorithm (GA). In the implementation of GA, the outlet sequence on a distribution route is represented as a gene sequence on a chromosome. Since the fitness value of a chromosome is associated with total travelling distance of that route, the implementation of GA in this study is directed to obtain a smallest fitness value. The GA implementation shows that the total travelling distance can be reduced, up to a certain level, by increasing the number of iterations and the population size. The GA implementation is done using the programming language Octave.
Keyword: GA, route, total distance, TSP

Judul: Penyelesaian Vehicle Routing Problem pada Pendistribusian Sayuran Dataran Tinggi Menggunakan Algoritme Genetika (Studi Kasus PT Saung Mirwan)
Abstrak: Vehicle routing problem (VRP) is an important issue on a transportation system that aims at minimizing the total vehicle mileage to reduce vehicle operating cost to a minimum. Vehicle routing problem belongs to the class of non-polynomial hard (NP-hard), which generally uses a heuristic approach to find a solution. In this time, Vehicle routing problem resolution will be applied to the distribution of highland vegetables from PT. Saung Mirwan as the vegetable distribution center. The problems that often arise in the distribution of highland plain vegetables is to how minimize the total of transportation costs without sacrificing the goal completion time to reduce the risk of the decline in the quality of vegetables during the trip. Issues will become increasingly complex if the vehicle routing problem is flexible to changes that occur in the limit or the value of decision variables. The problems encountered in this case include heterogeneous multi fleet VRP, single source, single trip, and multi-product. Therefore, this research used genetic algorithm optimization method (GA) to solve the problem. Genetic algorithm is one of the heuristic methods, which is analogous to the process of evolution by natural selection phase, crossover and mutation. In this paper a simulation is performed by searching the optimum solution to the location of the distribution as the destination points. Optimum solutions are obtained in the form of division of highland vegetable distribution channels that meet the existing constraints. As a solution, there was reduction of the distribution time of about 1 hour 58 minutes or an increase in time efficiency by approximately 32.22% and a reduction of the fleet utilization by 1 fleet or an increase of fleet efficiency by 14.28%.
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Judul: Hydroxyapatite-Chitosan Composite Coating on Stainless Steel 316 to Improve Corrosion Resistance
Abstrak: Metals that were used in bone implantation should have good corrosion resistance that were not easily corroded when implanted into the body. Metal corrosion resistance of stainless steel 316 can be enhanced through the metal coating by hydroxyapatite-chitosan composite with composition ratio of hydroxyapatite (gram) and chitosan 3% (mL) 0.2:0, 0.2:0.1, 0.2:0.5, 0.2:1.0, and 0.2:1.5. Besides improving the corrosion resistance of metal, the presence of chitosan also maintain the position of hydroxyapatite on metal surfaces. Corrosion resistance increases with increasing amount of chitosan added and the best composition of hydroxyapatite-chitosan composite was 0.2:1.0.
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