Judul: Pemodelan Penjadwalan Kegiatan Belajar Mengajar Menggunakan Integer Linear Programming: Studi Kasus Di Lembaga Bimbingan Belajar Ganesha Operation Bogor
Abstrak: Bimbingan belajar Ganesha Operation Bogor menghadapi masalah setiap semester dalam membuat penjadwalan kegiatan belajar mengajar. Permasalahan ini dapat dimodelkan sebagai masalah Integer Linear Programming (ILP) yaitu masalah optimasi dengan fungsi objektif dan kendala yang linear serta variabel integer. Penelitian ini bertujuan untuk membangun model matematika masalah penjadwalan kegiatan belajar mengajar di Ganesha Operation Bogor ke dalam bentuk ILP dan menentukan penjadwalan terbaik dalam satu semester. Fungsi objektif dari permasalahan ini ialah memaksimumkan banyak pertemuan setiap mata pelajaran dalam satu semester. Kendala dari pemodelan meliputi kapasitas ruang belajar, waktu luang siswa, pengajar dan kendala gedung yang digunakan. Setiap minggu kelompok belajar memunyai jadwal mata pelajaran yang berbeda, serta pengajar yang tidak selalu sama dalam setiap pertemuan untuk mata pelajaran yang sama. Dari proses software LINGO 11.0, nilai total fungsi objektif sebesar 1088 yang menunjukkan bahwa banyaknya penjadwalan maksimum ada 1088 jadwal, sesuai dengan yang diinginkan.
Keyword: Integer, Optimization, Objective function, Constraints, Optimasi, Fungsi objektif, Kendala, Pemrograman linear, Integer programming

Judul: Penjadwalan Kegiatan Belajar Mengajar di Lembaga Bimbingan Belajar dengan Menggunakan Integer Linear Programming dan Weighted Sum Method
Abstrak: This manuscript provides integer linear programming model to schedule teachers in a tutoring agency. The objective function of this model is to maximize students achievement with regard to teacher performance and to minimize the total cost for teachers which includes daily wage costs and transportation costs. These two objective functions are combined into one objective function using a weighted sum method. The model assuming that: (1) the study group has been formed and each group had time and place of teaching and learning activities, (2) it considers time availability of the teachers, (3) a teacher can teach at different locations within a day, (4) there is no time lag between the two time periods of teaching in a day, except the pause for switching locations.
Keyword: weighted sum method., scheduling, integer linear programming, tutoring agency,

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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