Judul: Pengembangan Algoritma dan Analisis Sifat Fisis Model Mangsa-Pemangsa Berdasarkan Pendekatan Agent-based Model
Abstrak: Agent-based Model adalah sebuah pemodelan berbasis agen yang mengamati perilaku agen. Model mangsa-pemangsa dengan menggunakan model berbasis agen meninjau perilaku mangsa pemangsa di alam dan hubungan agen terhadap dinamika lingkungannya. Penelitian ini bertujuan untuk mempelajari aturan-aturan yang realistis dan membangun algoritma komputasi dari model mangsa-pemangsa serta menganalisis kejadian yang muncul dari model mangsa pemangsa menggunakan pendekatan Agent-based Model. Dalam penelitian ini didefinisikan beberapa aturan, yaitu agen dapat berkembangbiak, mekanisme pemangsaan yang dilakukan pemangsa, faktor kematian agen akibat usia, faktor kematian pemangsa akibat terlingkupi oleh mangsa, dan faktor kematian pemangsa jantan akibat kelaparan. Adanya emergent properties berupa pengorganisasian diri agen mangsa sehingga membentuk pertahanan diri yang membuat pemangsa jantan terdesak dan mati kelaparan. Keadaan tersebut menimbulkan bifurkasi yang terjadi pada sistem.
Keyword: Agent-based Model, model mangsa-pemangsa

Judul: Analisis Model Mangsa-Pemangsa Wang dengan Strategi Pemanenan Pemangsa yang Tidak Linear
Abstrak: Karya Ilmiah ini merekonstruksi salah satu model matematis dalam memodelkan peristiwa mangsa-pemangsa yang dikembangkan oleh Wang (2016) yaitu model mangsa-pemangsa dasar tanpa pemanenan dan model mangsapemangsa dengan pemanenan pada populasi pemangsa. Model mangsa-pemangsa dasar tanpa pemanenan dipengaruhi secara signifikan oleh parameter tingkat interaksi mangsa-pemangsa. Parameter tersebut jika nilainya diturunkan terus menerus berakibat terjadinya kepunahan pada populasi pemangsa. Model mangsapemangsa dengan pemanenan pada populasi pemangsa juga dapat terjadi kepunahan pada populasi pemangsa jika nilai parameter laju pemanenan pemangsa diturunkan atau nilai parameter usaha luar untuk pemanenan pemangsa dinaikkan. Perubahan nilai parameter mengakibatkan perubahan kestabilan titik tetap pada model mangsa-pemangsa. Strategi pemanenan diterapkan untuk mencegah kepunahan pada populasi mangsa maupun pemangsa dengan pemilihan nilai parameter tertentu. Pemilihan nilai parameter pada model pemanenan populasi pemangsa menyebabkan adanya bifurkasi Hopf yang ditandai oleh munculnya limit cycle.
Keyword: mangsa-pemangsa, titik kritis, limit cycle, bifurkasi Hopf

Judul: Enhancement of photon absorbtion on BaxSr1-xTiO3 thin films semiconductor using photonic crystals.
Abstrak: In this research, has been conducted BaxSr1-xTiO3 (BST) thin films manufacturing for mole fraction x = 0.25, 0.35, 0.45, and 0.55; and concentration of 1 molar using chemical solution depositon (CSD) method. The materials, which are used in this research, are barium acetate [Ba(CH3COO)2, 99%], strontium acetate [Sr(CH3COO)2, 99%], titanium isopropoxide [Ti(C12O4H28), 97.999%], gallium trioxide [Ga2O3], 2-methoxyethanol [H3COOCH2CH2OH, 99%] and 1 x 1 cm of transparent conductive oxide (TCO) glass as substrate. Two BST thin films are made that for BST thin films which are doped by 10% galium (BGST) as p-type layer and pure BST solution as n-type. BST solution is made by reacting barium acetate [Ba(CH3COO)2, 99%], strontium acetate [Sr(CH3COO)2, 99%] and titanium isopropoxide [Ti(C12O4H28)] into 2-methoxyethanol solvent [H3COOCH2CH2OH, 99%] in accordance with mass gram for each x value. While, BGST solution is made in the same way as BST solution, plus adding gallium at 10% of the mass of BST. Once all materials are reacted, then vibrated using ultrasonic for 90 minutes, and followed by coating BGST / BST on the TCO substrate. Once the layer is formed, then annealed for 15 hours at temperature of 500 °C with increasing rate of 1.67 oC/minute. Characterizations of BST thin films with or without photonic crystals include the absorbance and transmittance in the visible light spectrum, as well as the electrical photoconductivity characterizations. From BST thin films without photonic crystals indicate that our thin films have light absorption area on almost the entire range of the visible light spectrum even to the infrared range with absorption value over than 67.6%, in addition, it can be seen that the maximum absorbance of BST thin films for all mole fractions lie in blue to green light spectrum region, 457 nm ≤ λ ≤ 570 nm and the minimum in yellow to red light spectrum region, 570 nm ≤ λ ≤ 678 nm. The largest absorbance is found at x = 0.25 with average absorbance value of 92.04% and maximum and minimum absorbance peaks at wavelength of 500.89 and 657.72 nm, respectively. At x = 0.35, average absorbance value decreased to 83.55% with maximum and minimum peaks at 505.73 and 613.68 nm, respectively. Then increased to 91.16% at x = 0.45 with maximum and minimum peaks at 506.04 and 618.56 nm, respectively. At x = 0.55, average absorbance value decreased to 80.12% with maximum and minimum peaks at 507.85 and 608.79 nm, respectively. Moreover, it can be seen that the addition of barium mole fraction leads to wider maximum absorbance or minimum transmittance peaks and narrower minimum absorbance or maximum transmittance peaks in the same range of the green and blue & red light spectrums, respectively. BST thin films with photonic crystals show increasing in absorption for all x values in the range of 3.04 into 13.33%. At x = 0.25, average absorbance percentage increased 3.96% from 92.4 into 95.68%, for x = 0.35 average percentage increased 7.07% into 89.45 from 83.55%. Furthermore, average absorbance of BST thin films at x = 0.45 increased 3.04% from 91.16 into 93.93% and x = 0.55 has
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