Judul: Penyelesaian Vehicle Routing Problem  with Simultaneous Delivery and Pickup: Studi Kasus Pendistribusian LPG 3 kg
Abstrak: Permasalahan rute pendistribusian termasuk dalam vehicle routing problem (VRP). VRP memiliki beberapa variasi, salah satunya adalah vehicle routing problem with simultaneous delivery and pickup (VRPSDP). Pengaplikasian VRPSDP dapat dilihat dari pendistribusian tabung LPG 3 kg, di mana agen mengirim tabung terisi ke pangkalan dan mengambil tabung kosong dalam satu kali perjalanan. VRPSDP dapat diselesaikan menggunakan metode eksak dan heuristik. Pada penelitian ini, dijelaskan bagaimana algoritme genetika mampu menyelesaikan masalah perutean kendaraan untuk mendistribusikan tabung LPG 3 kg pada PT Anten Surya Saputra. Algoritme genetika merupakan salah satu metode heuristik yang mendekati solusi optimal melalui beberapa proses, di antaranya seleksi, kawin silang, dan mutasi. Hasilnya, algoritme genetika mampu memberikan solusi yang mendekati optimal dalam waktu yang relatif lebih singkat dibanding metode eksak, dengan rata-rata persentase selisih solusinya adalah 6.32%., Distribution route problems are included in the vehicle routing problem (VRP). VRP has several variations, one of them is the vehicle routing problem with simultaneous delivery and pickup (VRPSDP). The application of VRPSDP can be seen from the distribution of 3 kg LPG, where the agent sends filled tubes to the base and pick up empty tubes in one trip. VRPSDP can be solved using exact and heuristic methods. In this study, it is explained how the genetic algorithm is able to solve the problem of vehicle routing to distribute 3 kg LPG at PT Anten Surya Saputra. Genetic algorithm is a heuristic method that approaches the optimal solution through several processes, including selection, crossover, and mutation. As a result, genetic algorithms are able to provide sub-optimal solutions in a relatively shorter time than the exact method, with an average percentage of the difference in solutions is 6.32%.
Keyword: 3 kg LPG, distribution, genetic algorithm, vehicle routing problem, VRPSDP

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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