Judul: Seed Characterization of Foxtail Millet  (Setaria italica L. Beauv.) ICERI and Botok Genotypes Using Digital Imaging  Technology
Abstrak: Karakterisasi biji berukuran kecil secara manual, seperti biji hotong, membutuhkan ketelitian yang tinggi, cenderung subjektif, dan membutuhkan waktu yang relatif lama. Oleh karena itu, perlu dikembangkan suatu metode yang efisien dan akurat untuk mengkarakterisasi biji hotong, salah satunya dengan memanfaatkan teknologi citra digital (digital imaging). Analisis citra digital dengan ImageJ dapat memperoleh data kuantitatif untuk morfologi bentuk biji seperti jumlah, ukuran, perimeter, width, height, circularity, aspect ratio, round, dan solidity. Penelitian ini bertujuan untuk mengembangkan model pendugaan bobot 100 biji genotipe hotong yang berasal dari Indonesia menggunakan perangkat lunak pencitraan digital ImageJ v1.53. Penelitian ini dilaksanakan pada bulan November 2021 hingga Februari 2022 di Laboratorium Biologi dan Biofisika Benih, Departemen Agronomi dan Hortikultura, Institut Pertanian Bogor, Dramaga, Bogor. Penelitian ini terdiri atas dua tahap percobaan. Percobaan pertama menggunakan 14 genotipe hotong Indonesia dari ICERI dan Botok untuk mengembangkan model pendugaan karakter jumlah biji dan bobot 100 biji. Model y = 329,17x2 - 2,3606x + 0,0774 (R²= 0,948) menunjukkan korelasi positif dan sangat nyata (r=0,974, p<0.01) antara prediksi bobot 100 butir menggunakan ImageJ dengan bobot 100 butir aktual. Model tersebut kemudian divalidasi pada percobaan kedua yang menggunakan biji dari 30 galur F3 hasil persilangan Botok-4xICERI-6. Hasil validasi menunjukkan korelasi positif dan sangat nyata (r=0,606, p<0.01) antara nilai prediksi bobot 100 butir dan nilai aktualnya, Manual characterization of small size seeds, such as seed of foxtail millet, requires high accuracy, tends to be subjective, and requires a relatively long time. Therefore, it is necessary to develop an efficient and accurate method to characterize foxtail millet seeds, one of which is by utilizing digital image technology (digital imaging). Digital image analysis with ImageJ can obtain quantitative data for seed morphology such as number, size, perimeter, width, height, circularity, aspect ratio, round, and solidity. The objective of this study was to develop a model for estimating 100 seed weight of Indonesian foxtail millet genotypes utilizing digital imaging software ImageJ v1.53. This research was conducted from November 2021 to February 2022 at Seed Biology and Biophysics Laboratory, Department of Agronomy and Horticulture, IPB University, Dramaga, Bogor. This research consisted of two steps of experiments. The first experiment utilized 14 Indonesian foxtail millet from genotypes of ICERI and Botok to develop a model for estimating 100 seed weight. A model of y = 329.17x2 – 2.3606x + 0.0774 (R²= 0.948) showed a positive and highly significant correlation (r=0.974, p<0.01) between predicted 100 seed weight using ImageJ with the actual 100 seed weight. The model was then validated in the second experiment that utilized seeds from 30 F2 plants from Botok-4xICERI-6 crossing. The validation results showed a positive and highly significant correlation (r=0.606, p<0.01) between the predicted and actual values of 100 seed weight.
Keyword: bobot 100 biji, jumlah biji, ImageJ, korelasi, model estimasi

Judul: Digital Imaging for Seed Characterization of Indonesian  Foxtail Millet (Setaria italica (L.) Beauv) Local Genotypes
Abstrak: Karakterisasi biji termasuk ukuran, jumlah, dan bobot biji merupakan karakter penting dalam proses seleksi genotipe. Karakterisasi biji secara manual pada tanaman berbiji kecil seperti hotong (Setaria italica (L.) Beauv) tidak mudah untuk dilakukan. Karakterisasi biji secara manual rentan terhadap kesalahan dan memerlukan waktu cukup lama. Penggunaan teknologi citra digital diharapkkan dapat mempercepat, memudahkan, dan meningkatkan akurasi karakterisasi biji hotong. Tujuan penelitian ini adalah pemanfaatan perangkat lunak citra digital ImageJ v1.53 untuk melakukan karakterisasi biji hotong dan mengembangkan model estimasi bobot 100 butir biji menggunakan biji hotong genotipe lokal Indonesia. Penelitian ini dilaksanakan pada bulan November 2021 hingga Febuari 2022 di Laboratorium Biologi dan Biofisik Benih, Departemen Agronomi dan Hortikultura, IPB, Dramaga, Bogor. Penelitian terdiri atas dua tahap percobaan. Percobaan pertama menggunakan 14 genotipe hotong lokal Indonesia untuk melakukan karakterisasi morfologi biji hotong dan membuat model pendugaan untuk bobot 100 butir biji. Model tersebut lalu divalidasi pada percobaan kedua yang menggunakan biji dari 30 famili F3 hasil persilangan ICERI-6xBotok-4. Model pendugaan yang didapatkan yaitu 11,748x - 0,0772 (R2=0,811) menunjukan korelasi positif dan sangat nyata (r=0,901, p<0,01) pada saat bobot prediksi 100 butir biji menggunakan ImageJ dan bobot 100 butir biji aktual dibandingkan. Model pendugaan kemudian divalidasi pada percobaan kedua dan juga menghasilkan korelasi positif dan sangat nyata (r=0,825, p<0,01). Selain mengestimasi jumlah biji, perangkat lunak ImageJ dapat mengestimasi beberapa karakter biji lainnya yaitu perimeter, width, height, circularity, aspect ratio, round, dan solidity., Seed characters, including seed size, seed number and seed weight, are important characters in genotypes selection. Manual characterization of seeds in plants with small seed size, such as in foxtail millet (Setaria italica (L.) Beauv) is challenging, prone to errors, and needs plenty of time. Utilization of digital imaging technology is expected to provide faster, easier and more accurate seed characterization in foxtail millet. The objective of this study was to obtain morphological seed characters and utilize ImageJ v1.53. digital imaging software to develop model in estimating 100 seed weight using Indonesian foxtail millet local genotypes. This research was conducted from November 2021 to February 2022 at Seed Biology and Biophysics Laboratory, Agronomy and Horticulture Department, IPB University, Dramaga, Bogor. This research consisted of two steps of experiments. The first experiments utilized 14 Indonesian foxtail millet local genotypes to obtain morphological seed characters and develop the model in estimating 100 seed weight character. The model was then validated in the second experiment that utilized seeds from 30 F3 lines from ICERI-6xBotok-4 crossing. A model of 11.748x – 0.0772 (R2=0.811) showed high a positive and highly significant correlation (r=0.901, p<0.01) between predicted 100 grain weight using ImageJ with the actual 100 grain weight. The model was then validated in second experiment and shown high a positive and highly significant correlation (r=0.825, p<0.01). The ImageJ software could also identify other seed characters including perimeter, width, height, circularity, aspect ratio, round, and solidity.
Keyword: 100 grains weight, Estimation model, ImageJ, Seed area, Seed shape

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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