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: The Rescheduling Principle to Minimize Total Delay on Train with Mixed Integer Linear Programming Method
Abstrak: Salah satu transportasi massa yang cukup diminati masyarakat karena efektivitasnya adalah kereta rel listrik atau biasa dikenal sebagai KRL. KRL tentunya memiliki jadwal tetap yang mengatur perjalanannya. Namun, dalam pelaksanaannya, bukan tidak mungkin akan ada gangguan yang menunda perjalanan kereta. Oleh karena itu, dibutuhkan sebuah sistem untuk menjadwalkan ulang perjalanan kereta. Pada karya ilmiah ini, disediakan sebuah model untuk membentuk jadwal perjalanan baru bagi kereta dengan meminimumkan total waktu keterlambatan. Model tersebut diformulasikan sebagai model Mixed Integer Linear Programming dan diaplikasikan pada jadwal KRL Commuter Line milk PT. KAI menggunakan rute KRL Bogor-Jakarta Kota. Dalam penerapannya, model ini menghasilkan tiga jadwal baru dengan keterlambatan minimum untuk tiga contoh kasus yang telah dibuat., Commuter rail, also known as KRL, has become one of the most preferably mass transportation for its effectiveness. KRL itself surely has a routine schedule to organize its trek every day. But on its implementation, any disruption would blackout the train schedule. Therefore, a system to re-scheduling the train schedule is very needed. On this paper, a model to make a new schedule for the train and minimizing the total delay time is presented. This model is considered as a Mixed Integer Linear Programming model and applicated on KRL Commuter Line’s schedule, using the route of Bogor-Jakarta Kota KRL. On its application, this model generates three new schedules with minimum total delay for three cases provided.
Keyword: mixed integer linear programming, rescheduling, train

Judul: Durability of Specific Immunoglobulin (Ig) Y Againts Influenza and Covid-19 in Sunscreen
Abstrak: The benefit of specific immunoglobulin Y (Ig Y) as an active ingredient in personal care products such as sunscreen has not been properly studied. Our study aims to evaluate the reliability of specific IgY against influenza and the COVID-19 virus in a sample sunscreen product. Specific IgY influenza and COVID-19 viruses were inserted in the sample sunscreen at two concentrations of 0.1% and 0.25%. Three treatments were observed: control (C) sunscreen without IgY, treatment 1 (T1) sunscreen with 0.1% IgY, and treatment 2 (T2) sunscreen with 0.25% IgY. Organoleptic observations were carried out to monitor changes in aroma, color, and texture, and sunscreen sampling was done every week for 6 weeks. The durability of IgY was evaluated using an enzyme-linked immunosorbent assay (ELISA) and a neutralization assay. Organoleptic observation from weeks 1 to 6 showed consistency in its aroma, color, and texture. Enzyme-linked immunosorbent assay and neutralization assay (NA) results of the T1 and T2 groups showed negative results except for sample T1 at week 5, which showed a positive result in the Influenza A ELISA. Based on the results, it seems that IgY concentrations of 0.1% or 0.25% were not optimal. However, this negative result might be due to low concentration of the IgY and the presence of beeswax, which inhibits IgY and causes it to dissolve in distilled water, thus preventing it from being detected in the assay.
Keyword: Immunoglobulin Y, Sunscreen, Influenza, COVID-19, Biological Activity