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.
Keyword: 

Judul: Optimasi Biaya Operasional Kereta Api dalam Sistem Loop Line Menggunakan Pemrograman Integer Taklinear
Abstrak: High demand for transportation that causes passenger’s congestion in some stations is one of the main problems faced by PT KAI commuter Jabodetabek (KCJ). This problem can be solved by determining optimal routes and frequencies of the trains. This paper presents a model to determine routes and travelling frequency for each route in order to minimize the total cost. The problem is modelled as a nonlinear integer programming. This model is implemented in Jabodetabek railway network that have been simplified. The parameters of the model include the demand of passengers, the capacity of trains, maximum travelling of train for each route, and operational costs. Developing model is started with identification of all the requirements of the system. All of the requirements then are formulated as linear equalities or inequalities. Ensuring the validity of model is done via solving several scenarios using the model. The solution of the model is obtained using LINGO 11.
Keyword: 

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