Judul: Scheduling Problem of Teaching and Learning Activities: Case Study at BTA College Bogor.
Abstrak: At every beginning of semester, some colleges may face the same problem in setting up schedules of teaching and learning activities with constraints of time and availability of rooms. Generally, in every semester, the number of registered students in the college are not always the same. Thus, it will generate problem which related to the classroom capacities. In this work, the teaching and learning activities scheduling problem can be modeled as an integer linear programming problem (ILP). ILP is the problem of optimization with linear objective function and constraints, which involves some integer variables. The model of scheduling problem is formulated under the following constraints: (i) the availability of rooms, (ii) the time period of Monday-Wednesday-Friday or Tuesday-Thursday- Saturday, (iii) the number of courses and (iv) the availability of the toturs. In this work, we discuss how to formulate the scheduling problem o f teaching and learning activities into ILP by taking a case study at BTA college. To solve this model we use Lingo 8.0 software with branch and bound method.
Keyword: 

Judul: Courses Scheduling Problem at Junior High School with Integer Linear Programming.
Abstrak: The course scheduling at junior high school is an important task. The purpose of course scheduling is to allocate courses according to their classification and to satisfy teachers preferences on teaching and other constraints. In this paper, the preferences and constraints are accommodated by means of coefficients as weights attached into courses as well as teachers. The problem is formulated as a minimization problem. The preferences and constraints with smaller weights framework indicate more preffered time periods, and vice versa. The scheduling problem in this paper is modeled in term of integer linear programming (ILP) and Lingo 8.0 is used to solve the problem. The result of the research is a fully defined schedule for “Masa Depan” junior high school.
Keyword: 

Judul: Natural Pearlescent Pigment Dari Kristal Guanin Sisik Ikan Bandeng (Chanos Chanos)
Abstrak: Pearlescent pigment yang dikenal dengan nama pearl essence atau fish silver merupakan pigmen berwarna keperakan yang memiliki kenampakan seperti mutiara. Natural pearlescent pigment diperoleh dari sisik ikan dengan kandungan guanin 75-97%, dan kini mulai banyak digunakan pada industri personal care dan produk kosmetika. Penelitian ini bertujuan untuk menentukan teknologi ekstraksi natural pearlescent pigment dan karakteristik kualitatif kristal guanin pada sisik ikan bandeng (Chanos chanos). Perlakuan dalam penelitian ini meliputi ekstraksi menggunakan air deionisasi dengan sisik yang dibekukan terlebih dahulu, air deionisasi 10 οC, dimetil sulfoksida 15%, dan 25% (v/v). Hasil spektrum absorbansi UV-Vis menunjukkan kristal guanin merupakan pigmen berwarna putih berdasarkan serapan pada panjang gelombang 200-800 nm. Hasil terbaik diperoleh pada ekstraksi menggunakan air deionisasi dengan sisik beku nilai kristalinitas 68,4%, serapan gugus amina pada 3410 cm-1 dan gugus amida pada1681 cm-1, puncak intensitas 2θ pada sudut 27,7° yang menunjukan identitas dari kristal guanin anhidrat. Tingkat kandungan guanin sebesar 0,0455 ± 0,0033 g (0,46%).
Keyword: Dimetil sulfoksida, guanin, kosmetik, kristalinitas, pearlescent pigment