Judul: Penjadwalan Kegiatan Mengajar Bimbingan Belajar Menggunakan Integer Linear Programming: Studi Kasus Bintang Pelajar Cikarang
Abstrak: Penjadwalan menjadi salah satu permasalahan yang sering dihadapi dalam penugasan suatu organisasi termasuk lembaga pendidikan, salah satunya yaitu bimbingan belajar. Penjadwalan ini melibatkan kombinasi antara banyaknya tenaga pengajar, mata pelajaran, kelompok belajar, sesi belajar, dan ketersediaan ruangan. Tujuan dari penelitian ini adalah memodelkan masalah penjadwalan dengan meminimumkan bobot sesi belajar setiap kelompok lalu mengimplementasikan model tersebut pada masalah penjadwalan kegiatan mengajar di Lembaga Bimbingan Belajar Bintang Pelajar Cikarang. Masalah tersebut diselesaikan menggunakan integer linear programming. Dengan bantuan software Lingo 19.0 diperoleh solusi optimal berupa jadwal kegiatan mengajar untuk periode waktu satu bulan yang memenuhi seluruh kendala., Scheduling is one of the problems faced in the assignment of an organization including educational institutions, one of which is tutoring. This scheduling involves the number of teaching staff, subjects, study groups, study sessions, and room availability. The purpose of this study is to model the scheduling problem by minimizing the weight of each group's study sessions and then implement the model on the scheduling teaching activities at Tutoring Institutions Bintang Pelajar Cikarang. That problem was solved using the integer linear programming method. With the help of Lingo 19.0 software, an optimal solution is obtained in the form of a teaching activity schedule for one month that satisfies all constraints.
Keyword: Bintang Pelajar Cikarang, integer linear programming, learning session weight, scheduling, tutoring institutioins

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: Characterizations of low alloy steel sae 4422  plated with chromic acid (Cro3)
Abstrak: Characterizations of low alloy steel SAE 4422 plated with chromic acid (CrOrO3) was use Optical Microscopy (OM), Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD), RD),Energy Dispersive Analysis of X-Ray (EDAX), Hardness Test and Roughness Test. Microstructures analysis exhibits cracks and grain boundaries microcracks as a characteristics of chrome metal found at plating metal. Perlite and Ferrite as grains of steel found at base metal with grain boundaries around it. Phase analysis of plating metal appropriate to chrome metal with lattice constant (a) is 2.559 Å and phase analysis of base metal appropriate to iron ferrite with lattice constant (a) is 3.318 Å. Both plating and base metal have cubic system. Chemical analysis of plating metal at surface section exhibits that cracks area have highest value of carbon element compare with grains and grains boundaries area. While chemical analysis of base metal at cross section exhibits that perlite have highest value of carbon element compare with ferrite and grain boundaries. The hardness value of plating metal at surface section and cross section are 753 and 637 VHN. While, the hardness value of base metal and interface area at cross section are 205 and 373 VHN. The roughness value at measurement points of chrome surface for as received sample are 0.445 μm. Observation used Optical Microscopy and Scanning Electron Microscopy exhibits surface irregularities combine to form surface texture of plating metal at surface section.
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