Judul: Aplikasi Teknologi Near Infrared untuk Pendugaan Viabilitas Benih Padi (Oryza sativa) Varietas Ciherang
Abstrak: Near infrared (NIR) spectroscopy in the range of 1000-2500 nm was studied for its ability to predict the seed viability such as germability, vigor index, maximum growth potential and the biochemistry composition such as water content, soluble protein, and free faty acid of the ciherang paddy seed following 0, 2, 4, 6 and 8 days acclerated aging (45oC, RH >90%). A total of 60 sample groups consist of 40 g paddy seed per sample ware used. Fourty samples were used for calibration and 20 samples were used for validation. Artificial neural network (ANN) and partial least squares (PLS) regression methods were used to build the prediction model. The good model should have a low standard error of calibration (SEC), a low standard error of performance (SEP), a high correlation coefficient, a small difference between SEC and SEP and have ratio performance deviation (RPD) higher than 2.5. The result showed that kind of original and pre processing spectra influenced the value of evaluation ANN and PLS model. The structure of ANN also influence the value of evaluation model. The best model to predict germability was 10-5-3 ANN using standard normal variate of reflectan spectra with RPD = 2.2359 and r validation = 0.8947, to predict vigor index was 10-5-1 ANN using 2nd derivative of reflectan spectra with RPD=3.6842 and r validation 0.9645, to predict maximum growth potential was 10-5-1 ANN using 2nd derivative of reflectan spectra with RPD=2.5572 and r validation 0.9204, to predict water content was PLS using absorbant spectra with RPD=9.6028 and r validation 0.9946, to predict soluble protein was 5-5-1 ANN using 2nd derivative of reflectan spectra with RPD=3.9615 and r validation 0.9686, and to predict free faty acid was 10-20-1 ANN model using 2nd derivative of absorbant spectra with RPD=4.0290 and r validation 0.9688.
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Judul: Spectral Pattern Analysis of Rice Varieties with Proximal Sensing Method and Sentinel-2 Imagery
Abstrak: Pemantauan pertumbuhan padi melalui berbagai wahana penginderaan jauh seperti satelit Sentinel-2 sudah banyak dilakukan, namun variasi ketinggian dan bauran reflektansi menyebabkan tingkat akurasi berbeda. Proximal sensing memungkinkan pemantauan dekat (ground-level) melalui sensor beresolusi tinggi. Spectroradiometer merupakan perangkat penginderaan proksimal yang mampu merekam pola spektral secara kontinu suatu objek, sehingga informasi yang diperoleh lebih rinci. Penelitian ini bertujuan menganalisis karakteristik pola spektral tanaman padi varietas Ciherang dan Ketan Grendel berdasarkan metode proximal sensing dan menganalisis keterkaitan pola spektral kedua varietas hasil pengukuran spectroradiometer dengan citra Sentinel-2. Berdasarkan analisis spektral, varietas Ciherang mencapai nilai reflektansi maksimum untuk panjang gelombang red-edge dan NIR pada 56 HST kemudian menurun pada 81 HST, sedangkan varietas Grendel baru mencapai nilai reflektansi maksimum pada 81 HST dan menurun pada 86 HST. Berdasarkan regresi linier, hubungan antara nilai reflektan hasil pengukuran spectroradiometer dan citra Sentinel-2 pada 23 HST memiliki nilai R² yang lebih rendah yaitu 0.5869 dan 0.5178. Hal ini dikarenakan tanaman belum berkembang dan permukaan sawah belum tertutup seluruhnya oleh kanopi tanaman. Hubungan nilai spektral pada 56, 81, 86, dan 90 HST menunjukkan nilai reflektansi pengukuran spectroradiometer setara atau ekuivalen dengan nilai reflektansi hasil ekstraksi citra Sentinel-2 dengan rata-rata R² di atas 86%., Rice growth monitoring through remote sensing such as Sentinel-2 imagery has been widely used, yet the accuracy level is different due to variations in altitude and object reflectance. Proximal sensing provides site (ground-level) monitoring via high-resolution sensors. Spectroradiometer is a proximal sensing device that can continuously record the spectral pattern of an object. This research aims to analyze spectral pattern characteristics of Grendel sticky and Ciherang rice varieties based on proximal sensing and to analyze relationship between reflectance value of spectroradiometer and Sentinel-2. Based on spectral analysis, Ciherang variety reached the maximum reflectance value for red-edge and NIR wavelength at 56 DAP and then decreased at 81 DAP, while Grendel variety just reached the maximum value at 81 DAP and decreased at 86 DAP. The relationship between the reflectance value of spectroradiometer and Sentinel-2 at 23 DAP had a lower R² value, 0.5869 and 0.5178. These are because plants have not yet developed and the rice fields surface has not been completely covered by plant canopy. Relationships at 56, 81, 86, and 90 DAP indicated reflectance values of spectroradiometer measurement are equivalent to value of Sentinel-2 image extraction with an average of R² above 86%.
Keyword: Ciherang rice, Grendel sticky rice, reflectance value, spectroradiometer

Judul: Formulasi Hamiltonian untuk Menggambarkan Gerak Gelombang Soliter Dimensi Tiga di Permukaan Laut
Abstrak: Gelombang permukaan adalah gelombang yang terjadi perbedaan rapat massa antara air dan udara. Salah satu gelombang permukaan yang ditinjau adalah gelombang soliter. Formulasi gelombang soliter dilakukan dengan menggunakan formulasi Hamiltonian.
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