Judul: Mapping of Changes in Seagrass Areas Using Sentinel-2A Imagery on Harapan and Kelapa Islands Waters, Kepulauan Seribu National Park
Abstrak: Lamun merupakan tumbuhan berbunga (Angiospermae) yang dapat ditemukan di pesisir pantai hingga perairan dangkal dan dapat beradaptasi terhadap perairan bersalinitas. Padang lamun memiliki fungsi penting antara lain sebagai habitat biota laut alami dan dapat memperlambat pergerakan arus serta gelombang ke darat. Aktivitas manusia seperti kegiatan perikanan, budidaya, pariwisata dan alih fungsi lahan untuk pembangunan dapat mengakibatkan kerusakan pada lamun yang berakibat pada penurunan luas padang lamun. Penelitian ini bertujuan untuk memetakan sebaran dan perubahan luas lamun di perairan Pulau Harapan dan Pulau Kelapa. Penelitian ini diawali dengan pengambilan data lapang dan pengolahan citra satelit Sentinel-2A berupa preprocessing citra dan koreksi kolom air. Selanjutnya dilakukan klasifikasi maximum likelihood pada citra sentinel-2A akuisisi 22 November 2015 dan 24 April 2021. Hasil klasifikasi citra diperoleh tiga kelas yaitu kelas non lamun, lamun padat, dan lamun sedang. Pada tahun 2015 luas area padang lamun seluas 0,92 km2 dan non lamun 1.58 km2, di tahun 2021 luas lamun seluas 0,70 km2 dan non lamun 1.79 km2. Terjadi perubahan luas area lamun menjadi non lamun seluas 0.52 km2 dan area non lamun yang menjadi lamun seluas 0.30 km2. Nilai overall accuracy yang diperoleh sebesar 74.17% sudah memenuhi standar minimal 60% dari Badan Informasi Geospasial., Seagrass is a flowering plant (Angiospermae) found on the coast in shallow waters and could adapt to salinity waters. Seagrass beds have important functions as a natural habitat for marine organisms and reduce the movement of currents and sea waves into the land. Human activities such as fishing, aquaculture, tourism, and land conversion for development can cause damage to seagrass, resulting in a decrease in the area of seagrass beds. This study was to map the seagrass distribution and detect changes in the seagrass area in the waters of Harapan and Kelapa Islands. This research begins with field data collection and processing of Sentinel-2A satellite imagery, image preprocessing, and water column correction. The next step is the maximum likelihood classification is carried out on the Sentinel-2A image with the acquisition on 22 November 2015 and 24 April 2021. The image classification results obtained are three classes: non-seagrass, dense seagrass, and medium seagrass. In 2015 the area of seagrass beds was 0.92 km2, and non-seagrass areas were 1.58 km2, while in 2021, the area of seagrass beds was 0.70 km2 and non-seagrass fields area was 1.79 km2. There was a changing area of seagrass becoming non-seagrass at about 0.52 km2, and the location of non-seagrass, which became seagrass, is 0.30 km2. The overall accuracy value obtained of around 74.17% already meets the minimum standard of 60% from the Geospatial Information Agency.
Keyword: Supervised classification, Seagrass, Area changes, Sentinel-2A imagery

Judul: Pemetaan Perubahan Luas Sebaran Lamun Menggunakan Citra Sentinel-2A di Pulau Pramuka, Kepulauan Seribu.
Abstrak: Lamun merupakan tumbuhan berbunga (Angiospermae) yang hidup di kolom air dan tumbuh subur di laut dangkal dan muara. Kerusakan ekosistem lamun salah satu penyebabnya, karena reklamasi dan pembangunan di garis pantai contohnya yaitu pembangunan dermaga. Tujuan penelitian ini adalah memetakan dan membandingkan perubahan luas sebaran lamun sebelum dan sesudah pembangunan dermaga baru di Pulau Pramuka, Kepulauan Seribu dengan menggunakan citra Sentinel-2A. Metode klasifikasi terbimbing yang digunakan dalam penelitian ini adalah algoritma maximum likelihood, dan uji akurasi menggunakan confusion matrix. Uji akurasi menghasilkan nilai overall accuracy sebesar 70.69 %. Luas sebaran lamun pada tahun 2016 sebesar 52.64 Ha dan tahun 2020 sebesar 47.61 Ha. Berdasarkan persentase tutupannya, tahun 2016 luas area tutupan lamun sedang sebesar 22.66 Ha, lamun padat sebesar 20.37 Ha, dan lamun sangat padat sebesar 9.61 Ha. Pada tahun 2020 luas area tutupan lamun sedang sebesar 19.72 Ha, lamun padat sebesar 13.3 Ha, dan lamun sangat padat sebesar 14.59 Ha., Seagrass is a flowering plant (Angiosperms) that lives in the water column and thrives in shallow seas and estuaries. Reclamation and development on the coastline, such as dock construction, is one of the causes of seagrass ecosystem damage. This study aims to map and compare changes in the distribution area of seagrass before and after the construction of a new dock on Pramuka Island, Kepulauan Seribu, using Sentinel-2A imagery. The supervised classification method used in this study is the maximum likelihood algorithm, and accuracy assessment is using the confusion matrix. The accuracy assessment resulting in an overall accuracy value of 70.69%. The distribution area of seagrass in 2016 is 52.64 Ha and in 2020 is 47.61 Ha. Based on the coverage percentage, in 2016, the area with medium seagrass cover is 22.66 Ha, the dense seagrass cover is 20.37 Ha, and the area with the highest density of seagrass cover is 9.61 Ha. In 2020, the area with medium seagrass cover is 19.72 Ha, dense seagrass cover is 13.3 Ha, and the highest density of seagrass cover is 14.59 Ha.
Keyword: Area changes, Dock, Mapping, Pramuka Island, Seagrass

Judul: Penentuan Nilai Eigen dan Vektor Eigen dari Matriks Tridiagonal 2-Toeplitz dengan Pendekatan Polinomial Chebyshev
Abstrak: The eigenvalues and eigenvectors of a matrix can be determined by finding its characteristic polynomials. The characteristic polynomials of a tridiagonal 2-Toeplitz matrix is shown to be closely connected to polynomials which satisfy the Chebyshev recurrence relationship. If the order of the matrix is odd, then the eigenvalues are found explicitly in terms of the Chebyshev zeros and the eigenvectors are found in terms of the polynomials satisfying the recurrence relationship. For even ordered matrices, the situation is more complicated. The problem in these cases is that although the Chebyshev recurrence formula is still applied, its initial values are not generating Chebyshev polynomials
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