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: The Application of Genetic Algorithm in Vehicle Routing Problem and Its Implementation on Rastra Distribution
Abstrak: Rute pendistribusian kendaraan terkait proses distribusi produk merupakan masalah yang dihadapi produsen dalam memenuhi kebutuhan konsumen. Penentuan rute distribusi kendaraan atau vehicle routing problem (VRP) bertujuan menentukan rute dan penggunaan kendaraan agar biaya yang dikeluarkan minimal. Pada penelitian ini akan dibahas rute pendistribusian kendaraan untuk mengantarkan beras sejahtera dari beberapa gudang penyimpanan ke desa/kelurahan tertentu yang dimiliki Perum Bulog kabupaten Ponorogo untuk satu dari dua belas periode. Salah satu desa/kelurahan memiliki permintaan yang melebihi kapasitas kendaraan, sehingga lokasi tersebut dapat dikunjungi kendaraan dengan pendistribusian terpisah. VRP dapat diselesaikan menggunakan metode eksak dan metode heuristik. Metode heuristik genetic algorithm dengan pencarian solusi awal melalui nearest neighbour diterapkan untuk masalah pendistribusian beras pada periode di Perum Bulog. Solusi yang dihasilkan oleh metode heuristik memiliki waktu yang lebih cepat dibandingkan solusi metode eksak., The vehicle distribution route related to the product distribution process is a problem faced by manufacturers in meeting consumer needs. Determination of vehicle distribution routes or vehicle routing problem (VRP) aims to determine the route and use of vehicles so that the costs incurred are minimal. In this study the route of distribution of vehicles to deliver prosperous rice from several storage warehouses to certain villages will be discussed, which is owned by Perum Bulog in Ponorogo Regency for one of the twelve periods. One of the village has a demand that exceeds the vehicle capacity, so that the location can be visited by vehicles with split delivery. VRP can be solved using exact methods and heuristic methods. The heuristic genetic algorithm method by searching for an initial solution through the nearest neighbour is applied to the problem of distributing rice during the period at Perum Bulog. The solution produced by the heuristic methods has a faster time than the solution of the exact methods.
Keyword: distribution, heuristic method, multidepot, split delivery, vehicle routing problem

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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