Judul: Analysis of Attack Rate of Yellow Rice  Stem Borer (Scirpophaga incertulas) Based on Climate in Majalengka Regency
Abstrak: Kabupaten Majalengka merupakan salah satu penghasil produksi padi terbesar di Jawa Barat dengan produksi 534.520,2 ton pada tahun 2021. Meningkatnya kebutuhan beras di Indonesia dapat diatasi dengan meningkatkan produksi padi. Hama S. incertulas yang menyebabkan penyakit pada tanaman padi bahkan dapat menyebabkan kematian pada tanaman muda. Peningkatan luas serangan hama tersebut dapat dipengaruhi oleh beberapa parameter iklim seperti suhu, kelembapan, curah hujan dan kecepatan angin. Penelitian ini bertujuan untuk mengetahui pengaruh kondisi iklim terhadap serangan OPT di daerah penelitian dan mengetahui nilai Ecoclimatic Indeks (EI) daerah penelitian dengan menggunakan model Climex 4.0. Analisis ini menggunakan hasil regresi dengan aplikasi Minitab dan nilai indeks ekoklimatologi yang diperoleh dengan menggunakan aplikasi Climex. Hasil analisis regresi menunjukkan nilai R² antara luas serangan hama dengan parameter iklim sebesar 24,49% berdasarkan parameter iklim selama sepuluh tahun. Hasil indeks ekoklimat (EI) memiliki nilai 51 yang termasuk dalam kategori sesuai dengan deskripsi hama penggerek batang padi kuning di wilayah tersebut. Oleh karena itu, dapat disimpulkan bahwa populasi hama dan tingkat serangan hama dapat dipengaruhi oleh kondisi iklim di Kabupaten Majalengka., Majalengka Regency is one of the largest producers of rice production in West Java with a production of 534,520.2 tons in 2021. The increasing need for rice in Indonesia can be overcome by increasing rice production. S. incertulas pests that cause disease in rice plants can even cause death in young plants. The increase in the area of pest attack can be influenced by several climatic parameters such as temperature, humidity, rainfall and wind speed. This study aims to determine the effect of climatic conditions on pest attacks in the study area and determine the value of the Ecoclimatology Index (EI) of the study area using the Climex 4.0 model. This analysis uses regression results with the Minitab application and the ecoclimatic index value obtained using the Climex application. The results of the regression analysis showed the R² value between the extent of pest attack and climatic parameters of 24.49% based on climatic parameters for ten years. The results of the ecoclimatic index (EI) have a value of 51 which is included in the category in accordance with the description of the yellow rice stem borer pest in the region. Therefore, we can conclude that the pest population and the level of pest attack can be influenced by the climatic conditions of Majalengka Regency.
Keyword: attack area, compare location, ecoclimatic index, regression analysis

Judul: Analysis Level of Yellow Rice Stem Borer (Scirpophaga incertulas) Attack Based on Climatic Conditions in Cilacap District
Abstrak: Penggerek batang padi kuning/PBPK (Scirpophaga incertulas) merupakan salah satu hama pada tanaman padi yang menyebabkan penurunan produksi padi. Salah satu faktor yang mempengaruhi keberadaan hama ini adalah faktor iklim, antara lain suhu, curah hujan, kelembaban relatif. Perkembangan PBPK dipengaruhi oleh kondisi iklim di suatu tempat tertentu. Tujuan penelitian ini adalah menganalisis potensi serangan hama penggerek batang padi kuning (Scirpophaga incertulas) berdasarkan nilai Ecoclimatic Index (EI) di Kabupaten Cilacap menggunakan model Climex 4.0. Keluaran compare location menunjukkan bahwa Kabupaten Cilacap memiliki nilai EI sebesar 78 (sangat sesuai). Keluaran compare years diperoleh nilai EI tertinggi 74 (sesuai) pada kondisi bulanan dan nilai EI tertinggi 92 (sangat sesuai) pada kondisi tahunan. Hasil penelitian menunjukkan bahwa curah hujan merupakan faktor iklim utama yang mempengaruhi perkembangan hama, hal ini didukung dengan nilai R2 sebesar 0.23. Analisis yang digunakan dalam penelitian ini menggunakan analisis kesesuaian wilayah dari software Climex dengan hanya mempertimbangkan faktor iklim tanpa melihat faktor lainnya. Kata Kunci : Climex, compare years, ecoclimatic index, penggerek batang padi kuning, Yellow rice stem borer/PBPK (Scirpophaga incertulas) is one of the pests on rice plants that causes a decrease in rice production. One of the factors that influence the presence of this pest is climatic factors, including temperature, rainfall, relative humidity. The development of PBPK is influenced by climatic conditions in a particular place. The purpose of this study was to analyze the potential attack of the yellow rice stem borer (Scirpophaga incertulas) based on the value of the Ecoclimatic Index (EI) in Cilacap Regency using the Climex 4.0 model. The compare location output shows that Cilacap Regency has an EI value of 78 (very suitable). The output of compare years has the highest EI value of 74 (suitable) in monthly conditions and the highest EI value of 92 (very suitable) in annual conditions. The results showed that rainfall is the main climatic factor that affects the development of pests, this is supported by the R2 value of 0.23. The analysis used in this study uses a regional suitability analysis from the Climex software by only considering climatic factors without looking at other factors. Keywords: Climex, compare years, ecoclimatic index, yellow rice stem borer
Keyword: Climex, compare years, ecoclimatic index, yellow rice stem borer

Judul: Hamiltonian formulation for linear waves motion in two layers fluid
Abstrak: The surface wave could be considered as a wave that separates two fluids, namely water and air. Based on this assumption, it is introduced the interfacial wave, a wave between two layers of fluid with different density. The formulation of interfacial waves motion begins with deriving the base equation of irrotational ideal fluid. Furthermore, according to irrotational fluid assumption, the base equation can be stated in velocity potential. In this derivation, the fluids domain is assumed to be restricted by rigid lid boundary conditions, both at the upper and lower limit. Therefore, the interfacial waves motion can be explained in a hamiltonian formulation. In the hamiltonian formulation, total energy is defined as the sum of kinetic and potential energy. The hamiltonian system is obtained from reduction of kinetic energy by using the Dirichlet Neumann Operator. The resulted kinetic energy equation is nonlinear. Therefore, this form is linearized by first part of the Taylor expansion. This linearization gives a dispersion relation of linear wave. Based on this dispersion relation, the phase speed of the linear wave depends on the density ratio of the two layers fluid.
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