Judul: Pola Respon Spektral Tanaman Pangan dan Kenampakannya pada Citra Drone Multispektral
Abstrak: Salah satu cara untuk memantau kondisi lahan adalah dengan melakukan identifikasi perkembangan tanaman melalui respon spektral menggunakan spektroradiometer, yaitu alat ukur cahaya yang mampu mengukur radiasi spektral pada rentang panjang gelombang yang dipancarkan dari suatu objek. Penelitian ini bertujuan untuk melakukan analisis pola respon spektral tiga varietas padi, ubi jalar dan bengkuang berbasis dari data spektroradiometer dan membandingkan karakteristik pola spektral hasil pengukuran spektroradiometer dan citra drone multispektral. Penelitian ini dilakukan di Desa Situ Gede, Kecamatan Bogor Barat, Kota Bogor. Respon spektral tanaman padi, ubi, dan bengkuang berbeda dan respon spektral setiap jenis tanaman juga berbeda pada panjang gelombang yang berbeda. Semakin bertambah umur tanaman maka nilai reflektan pada rentang inframerah akan meningkat. Nilai reflektan varietas Nawacita pada rentang inframerah memiliki nilai reflektan yang lebih tinggi dibanding dengan varietas Siliwangi dan Palmerah karena dipengaruhi oleh struktur internal daun, lebar kanopi, dan konsentrasi air. Hubungan antara nilai reflektan citra drone dengan nilai reflektan spektroradiometer untuk tanaman menunjukan rata-rata R² diatas 0,6, One of the ways to monitor land condition is identify plant growth through a spectral response using a spectroradiometer, a light measuring instrument capable of measuring spectral radiation in the wavelength range emitted from an object. This study aims to analyze the spectral response patterns of three varieties of rice, sweet potato and jicama based on spectroradiometer data and to compare the characteristics of the spectral pattern measured by the spectroradiometer and multispectral drone photos. This research was conducted in Situ Gede Village, West Bogor District, Bogor City. The spectral response on rice, sweet potato and jicama plants was different and the spectral response of each plant type was also different at different wavelengths. The older plants age, the reflectance value in the infrared range will increase. The reflectance value of the Nawacita variety in the infrared range has a higher reflectance value than the Siliwangi and Palmerah varieties because it is influenced by the internal structure of the leaves, the width of thecanopy, and the water concentration. The relationship of the reflectance value of the drone image with the spectroradiometer reflectance value for plants shows an average of R² above 0,6.
Keyword: multispectral drone, spectral pattern response, spectroradiometer

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: Truncated Stop Loss as a Optimal Solution of Reinsurance Agreement in One-Period Model
Abstrak: Reinsurance is one of risk management efforts of an insurance company, which is called the cedent. Similar with insurance, reinsurance constitutes the cedent to pay the premium. We consider one-period reinsurance model and derive a rule which minimizes the ruin probability of the cedent for a fixed reinsurance premium. Therefore, it is needed to construct an optimal reinsurance agreement for the cedent. The premium is calculated according to four different principles, i.e. economic, generalized zero-utility, Esscher, and mean-variance principles. Stop loss is a reinsurance contract which protect the insurance company for losses that exceed a certain amount. The result of this research shows that a truncated stop loss is an optimal agreement in the class of all reinsurance contracts with various premiums calculated using above mentioned principles.
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