In this paper, we studied ant colony optimization for solving integrated scheduling of production and distribution problems. We improved the ant colony optimization by adding double selections, there are roulette wheel and elitism selections. Roulette wheel selection is used to determine the path where ants pass through before knowing pheromone information in that path. Meanwhile, elitism selection is used to keep the best solution before the more optimum solution obtained. Then, ant colony optimization and improved ant colony optimization are implemented in solving integrated scheduling of production and distribution problem in PT. BFPI. The aim of this paper is to achieve optimum production and distribution schedule in order to minimize the total cost of production and distribution. We also compare the performance of both applied methods and draw a conclusion. The results show that the method we proposed has more advantage.

This study focuses on the forms of errors made by students in solving math problems, especially on the material of a two-variable system of linear equations. The purpose of this research is  describing detail the form of errors made by students based on error indicators according to the Newman Stages. The data collection technique used is observation. By collecting data in the form of written test results from students, the forms of errors made by students were obtained, including: at stage (1) the form of the error was wrong in writing down known information, incomplete in writing down the information contained in the question, and wrong in determining the information in question, at stage (2) it is not appropriate to write a mathematical model from known information, and does not use variable symbols to simplify calculations, at stage (3) does not operate similar variables, substitutes wrong values, does not apply rules of operation, miscalculations, and did not get the final result of the calculation process, at stage (4) did not change the variable symbol into the form that the question asked, did not provide information on the final answer, and wrote conclusions but did not match what the questions asked.

Tujuan penelitian ini adalah mengetahui media pembelajaran berbasis android yang efektif untuk meningkatakan hasil belajar peserta didik pada pembahasan trigonometri menggunakan metode jigsaw. Metode penelitian menggunakan metode komparasi dan eksperimen. Subjek penelitian ini yaitu peserta didik kelasiXIa sebagaiikelas kontrolidan kelasiXId sebagaiikelasieksperimen, dimanaimasing-masing kelas terdiri dari 25 peserta didik. Pertemuan yang dilaksanakan yaitu 6 kali pertemuan. Penelitian ini menggunakan metode pembelajaran jigsaw menggunakan mediaiberbasis android untukikelas Eksperimenidan metode konvensional untuk kelas kontrol. Hasil penelitian ini menunjukan bahwa  yaitu  maka semua kelas di nyatakan homogen dan dengan nilai 12.28  1.978. Berdasarkan hasil penelitian terdapat peningkatan hasil belajar kognitif peserta didik pada kelas eksperimen dengan menggunakan jigsaw. Hal ini dikarenakan penggunaan media android pada metode jigsaw lebih menarik minat dibandingan dengan menggunakan metodeikonvensional. Sehingga penggunakan metode jigsaw berbantu android akan lebih efektif dalam proses pembelajaran matematika.

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