Judul: Masalah Penjadwalan Kereta Secara Periodik dengan Biaya Minimum pada Jalur Ganda
Abstrak: Train scheduling problem is an interesting topic to be discussed, since train has become such an important mass transportation in Indonesia. For that reason, this paper discusses how to solve a minimum cost scheduling problem (MCSP). The train scheduling problem that minimizes operation cost is formulated by MCSP in the form of integer programming. MCSP can be divided into two sections, i.e. minimum cost train problem (MCTP) and scheduling problem. In the first step, the right train is chosen with MCTP for a route, which satisfies a minimum cost. Furthermore, the next step solves the scheduling problem for the chosen train. The schedule is formulated only for one time period, which is assumed periodic. This solution is carried out by LINGO 11.0. The result gives the train scheduling for the specific route, which has minimum operation cost.
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Judul: Masalah Penjadwalan Kereta Api Jalur Ganda Menggunakan Model Job-Shop
Abstrak: Train scheduling problem can be modeled as a special case of job-shop scheduling problems. Based on the job-shop scheduling concept, the train trip can be considered as a job, which will be scheduled on tracks as resources. In this paper, train scheduling model is formulated under common rules in railroad system, e.g. crossing, overtaking and headway rules. The crossing rule is not implemented for double track, because there are two tracks that can be used by two trains with different directions. The train scheduling model is expressed in the form of integer linear programming and solved by branch and bound algorithm to minimize the total makespan. The model is then implemented for double track case of Mass Rapid Transit (MRT) Lebak Bulus- Sisingamangaraja route, which involves 11 MRT Economy and 7 MRT Express trains using hypothetical data. The train time-space diagrams show that there is no conflicts occurred and the total makespan is 1502 minutes. The result, in particular, indicates that there is an 11 minutes delay for MRT Express. The length of the delay can be reduced by employing an additional delay constraint. But, of course, this will deteriorate the makespan.
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Judul: Pemanfaatan Ekstrak Bunga Rosela (Hibiscus sabdariffa L) Kaya Antioksidan Dalam Pembuatan Mayonnaise Berbahan Dasar Minyak Kelapa, Minyak Sawit, dan Minyak Kedelai
Abstrak: The addition of Rosella flower extract and utilization various oli such as coconut, palm and soy were being involved in production of mayonnaise. Mayonnaise is a kind of ketchup which use canola or olive oil, egg, salt, and pepper and had been developed in France. The addition of Rosella extract (5%, 10% and 15%) base on amount of oil that used in production. Mayonnaise formulation are 75-78% oil, 6-9% egg yolk and flavors. Hedonic and hedonic quality sensory evaluations tested base on kind of oil. Base on evaluation the addition of Rosella extract statistically influenced color and thickness of coconut oil mayonnaise, color of palm oil mayonnaise, color and taste of soy oil. Fat analyze showed that there were statistically no difference between selected mayonnaise as well as protein and carbohydrate. Antioxidant activity and anthocyanine analyze showed that there were statistically difference between mayonnaise. Highest antioxidant activity and anthocyannin reached by palm oil mayonnaise with 15% Rosella extract.
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