This study aims to analyse students' conceptual understanding of chemical equilibrium matter using Physics Education Technology (PhET) Interactive Simulations. Students' misconceptions can be caused by the difficulty in connecting the sub-microscopic, macroscopic, and symbolic levels of understanding in chemistry. The study was conducted at a secondary school with a total sample of 108 students using a quantitative research method. The results showed that multiple-choice questions of the two-tier Chemical Equilibrium Diagnostic Instrument (CEDI) used in this study meet with the Rasch measurement model. The students who answered correctly on content knowledge ranged from 11.1—90.7%. However, the percentage decreased to 11.1—84.3% once the content knowledge and reasons were combined. The option probability curve responses identified the students' misconceptions that were further investigated by interviews. PhET Interactive Simulations require improvements or additional features to help students better understand conceptual understanding through analogies of product and reactant molecules' movement in the equilibrium system.

Abstrak -Penelitian ini bertujuan untuk mengetahui penentuan nilai parameter pada model Exponential Smoothing. Penentuan nilai ini dilakukan dengan menggunakan algoritma genetik. Nilai konstanta parameter sangat menentukan keakurasian forecasting. Nilai parameter yang diperoleh dengan menggunakan algoritma genetik selanjutnya akan dibandingkan dengan nilai parameter yang sering digunakan dalam penelitian yakni: 0.1, 0.5, dan 0.9. Keakurasian forecasting dengan masing-masing dapat dilihat dari error yang digunakan. Berdasarkan hasil yang diperoleh, nilai yang diperoleh dengan menggunakan algoritma genetik menghasilkan nilai error yang paling kecil. Sehingga dapat disimpulkan bahwa penentuan nilai parameter dengan menggunakan algoritma genetik dapat meningkatkan akurasi forecasting.Kata kunciforecasting, parameter, exponential smoothing, algoritma genetik.

Perencanaan produksi yang optimal bertujuan untuk memaksimalkan keuntungan yang diperoleh, dengan mempertimbangkan keterbatasan sumber daya yang dimiliki. UKM Puguh Jaya merupakan usaha yang bergerak di bidang konveksi kain kasur. Terdapat beberapa jenis produk yang diproduksi di antaranya: Kain tipe 120, kain tipe 140, kain tipe 160. Perencanaan produksi di UKM ini dapat dipandang sebagai model program integer yang bertujuan memaksimalkan keuntungan, dengan menentukan jumlah produksi untuk masing-masing tipe serta mempertimbangkan semua keterbatasan sumber daya yang ada. Pencarian solusi untuk model ini dilakukan dengan algoritma Branch and Bound. Berdasarkan hasil perhitungan menggunakan software QM for Windows, diketahui bahwa penentuan jumlah produksi dengan menggunakan algoritma branch and bound memberikan peningkatan keuntungan sebesar 18.7% dibandingkan dengan keuntungan UKM Puguh Jaya sebelumnya. Kata Kunci : Optimasi, program integer, algoritma Branch and Bound

This study aims to develop a score equating application for computer-based school exams using parallel test kits that have 25% anchor items, the items are arranged according to the HOTS (High Order Thinking Skill) category and use a scientific approach according to the characteristics of physics lessons. So that the questions are made using stimulus, options, logical and systematic. The research method used is Research and Development (R&D), which begins with an analysis of the current needs of schools and takes advantage of technological developments so that it makes it easier for schools to organize, and then continued in the literature study to design a school exam model with its devices. Items as instruments for school exams were analyzed using the RASCH model. The principle of equating used in application development is the linear equating method.

This study aims to determine the item response theory model which is more accurate in estimating students' mathematical abilities. The models compared in this study are Multiple Choice Model and Three-Parameter Logistic Model. Data used in this study are the responses of a mathematical test of 1704 eighth-grade junior high school students from six schools in the Depok City, West Java. The Sampling is done by using a purposive random sampling technique. The mathematics test used for research data collection consisted of 30 multiple choice format items. After the data is obtained, Research hypotheses were tested using the variance test method (F-test) to find out which model is more accurate in estimating ability parameters. The results showed that Fvalue is obtained 1.089, and  Ftable is 1.087, the value of Fvalue > Ftable, so it concluded that Ho rejected. That means Multiple Choice Model is more accurate than Three-Parameter Logistic Model in estimating the parameters of students' mathematical abilities. This makes the Multiple-Choice Model a recommended model for estimating mathematical ability in MC item format tests, especially in the field of mathematics and other fields that have similar characteristics.