Judul: Optimisasi Penjadwalan Pesawat Terbang Menggunakan Integer Linear Programming: Studi Kasus Maskapai PT Citilink
Abstrak: Salah satu aspek yang terpenting dalam manajemen suatu maskapai penerbangan adalah menentukan jadwal dan rute penerbangan bagi setiap pesawat guna memenuhi kebutuhan pesawat terbang bagi setiap segmen penerbangan dalam seluruh jadwal penerbangan yang sudah ditentukan maskapai penerbangan. Menurut Bazargan (2004) ada empat tahap proses dalam manajemen perencanaan penerbangan, yaitu i) penjadwalan penerbangan, ii) penugasan armada, iii) penentuan rute pesawat terbang, dan iv) penjadwalan kru. Dalam proses pembuatan jadwal dan rute penerbangan bagi setiap pesawat terbang dilakukan melalui tahap penugasan armada dan penentuan rute pesawat terbang. Tahap penugasan armada menentukan jumlah pesawat untuk masing-masing armada yang akan digunakan, serta menentukan base untuk setiap pesawat. Tahap penentuan rute pesawat terbang menentukan rute dan waktu penerbangan untuk setiap pesawat. Karya ilmiah ini menyajikan model optimisasi masing-masing untuk tahap penugasan armada dan penentuan rute pesawat terbang dalam bentuk model integer linear programming (ILP). Model ini diimplementasikan pada kasus maskapai PT Citilink yang memiliki 254 penerbangan pada 24 kota di Indonesia. Hasil implementasi model memberikan jumlah minimum pesawat sebanyak 48 unit yang terdiri dari 41 unit Air Bus 320, 6 unit Boeing 737-300, dan 1 unit Boeing 737-400, dengan total biaya operasional minimum sebesar Rp 14 214 981 000.
Keyword: citilink, integer linear programming, penerbangan, penjadwalan pesawat, penugasan armada, rute pesawat

Judul: Optimasi Penjadwalan Armada Pesawat Terbang
Abstrak: One of the common issues faced by airline companies relies on fulfilling passenger demands for Origin-Destination (O-D) routes using all fleet types. This paper presents an optimization model to determine fleet assignment for each flight route in order to minimize total costs. The total costs consist of the operating cost and passenger spill cost. The model is considered as an integer linear programming which is further implemented within the Citilink airlines schedule, and was solved using software Lingo 11.0. The model produced a fleet assignment in order to fulfill demand for all O-Ds with minimum cost.
Keyword: fleet assignment, integer linear programming, optimization

Judul: Bioecology of Earthworm Pheretima darnleiensis
Abstrak: Pheretima darnleiensis is a native earthworm in Southeast Asia, India, Japan, and Indonesia, however there is lack of study on P. darnleiensis. Determining the characteristics of P. darnleiensis and the ecology surrounding its habitat is needed in order to culture the earthworm. Hence, this study was aimed to study the structure of several organs and morphological characters that can be used to identify P. darnleiensis and its habitat condition. Earthworms were collected in a plot of 100 x 100 x 20 cm in 10 locations and were identified. The structure of P. darnleiensis organs was studied histologically using paraffin. Pheretima darnleiensis did not have diverticula and stalked gland on copulatory pouches, nephridia occurred on bithecate spermatheca, and the first spermathecal pores were at segment 4/5. Based on this study, the highest population of P. darnleiensis was found in an area containing abundance of other earthworm species at 15 individuals/m2, plant cover at 25.00%, soil arthropods at 16.32 individuals/kg fresh soil, abiotic component cover at 78.50%, soil temperature at 27.42 ± 1.01 oC, soil pH at 5.77 ± 0.53, soil moisture at 19.83 ± 9.92%, organic carbon at 3.39%, N at 0.29%, P at 286.80 ppm, K at 500.00 ppm, sand at 28.76%, silt at 38.74%, and clay at 32.50%. Silt fraction could be considered as one of factors influencing P. darnleiensis abundance.
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