Judul: Assessment of Shoreline Changes in Muara Gembong Mangrove Area 2003-2023
Abstrak: Konversi mangrove menyebabkan abrasi dan akresi di Kecamatan Muara Gembong. Penelitian ini bertujuan mendeskripsikan kondisi mangrove dan menganalisis perubahan garis pantai kawasan mangrove Muara Gembong. Penelitian dilaksanakan di Desa Pantai Bahagia, Desa Pantai Bakti, dan Desa Pantai Sederhana. Penelitian ini menggunakan metode pengolahan citra satelit, analisis vegetasi, dan studi pustaka. Analisis data menggunakan metode DSAS, indeks dominasi jenis, indeks keanekaragaman mangrove, struktur dan komposisi jenis, analisis NDVI, analisis hidrologi, analisis WRPlot, serta analisis admiralty. Spesies mangrove yang mendominasi sempadan Muara Gembong yaitu jenis Avicennia marina dan Rhizophora mucronata. Berdasarkan NDVI, kerapatan mangrove berubah tiap tahunnya dengan didominasi kerapatan jarang. Garis pantai mengalami perubahan tiap tahunnya dengan Desa Pantai Bakti mengalami perubahan garis pantai paling signifikan selama tahun 2003-2023. Perubahan garis pantai rata-rata mengalami abrasi di ketiga desa dengan abrasi tertinggi 13,45 m dan luasan 49,37 ha di Desa Pantai Bahagia. Abrasi yang terjadi disebabkan karena faktor alam berupa banjir rob dan alih fungsi mangrove menjadi tambak oleh masyarakat sedangkan akresi yang terjadi disebabkan karena sedimentasi di sekitar muara Sungai Citarum.
Keyword: abrasion, accretion, mangrove, Muara Gembong, shoreline change

Judul: Study of Mangrove Land Cover Changes and Sea Level Rise on Coastal Vulnerability of Bekasi Regency
Abstrak: Perubahan tataguna lahan, khususnya tutupan mangrove sangat mempengaruhi kerentanan kawasan pesisir. Kecamatan Muara Gembong, Kabupaten Bekasi ditetapkan sebagai salah satu kawasan hutan lindung mangrove. Konversi lahan mangrove serta bencana erosi pantai mengancam kerentanan kawasan pesisir Kabupaten Bekasi. Penelitian ini mengkaji perubahan tutupan lahan mangrove serta menganalisis kerentanan pesisir wilayah Kabupaten Bekasi tahun 2000 dan 2020. Pengkajian perubahan tutupan lahan mangrove dilakukan dengan menggunakan supervised classification untuk membaginya menjadi 5 kelas tutupan lahan, yaitu mangrove, vegetasi, lahan terbangun, lahan terbuka, dan badan air, kemudian memvalidasinya menggunakan Normalized Difference Vegetation Index (NDVI). Metode coastal vulnerability index (CVI) digunakan untuk menilai kerentanan pesisir Kabupaten Bekasi. Klasifikasi kerentanan yang dilakukan di wilayah kajian yang dibagi menjadi 72 grid menunjukkan bahwa separuh diantaranya (36 grid) tergolong memiliki kerentanan tinggi. Penurunan tutupan mangrove dari tahun 2000 sampai 2020 sebesar 23,55% menyebabkan kerentanan Muara Gembong bertambah luas, yang ditunjukkan oleh tambahan 26 grid yang memiliki kerentanan tinggi. Melindungi mangrove yang ada dan merestorasi garis pantai yang terdegradasi pelu diprioritaskan untuk mengurangi risiko bencana di Kawasan pesisir Kabupaten Bekasi., Coastal areas are particularly vulnerable to the impacts of human induced climate change and land-use change, especially mangrove cover. Muara Gembong District, Bekasi Regency is designated as one of the mangrove protected forest. However, rampant conversion has been causing coastal erosion in Bekasi Regency. This study examines changes in mangrove land cover and analyzes the coastal vulnerability of the Bekasi Regency area in 2000 and 2020. The assessment of mangrove land cover change was carried out using supervised classification five classes of land cover, including mangroves, vegetation, built-up area, open land, and water bodies, then validate it using the Normalized Difference Vegetation Index (NDVI). The coastal vulnerability index (CVI) method was adopted to assessthe coastal vulnerability of Bekasi Regency. The vulnerability classification carriedout in the study area divided into 72 grids showed that half of them (36 grids) were classified as highly vulnerable. The decrease mangrove cover during 2000-2020 of 23.55% caused the vulnerability of Muara Gembong to increase, as shown by additional 26 grids that are highly vulnerability. Protecting the existing mangroves and restoring the degraded area should be prioritized to reduce risks of disaster in the coastal zone of Bekasi Regency
Keyword: climate change, CVI, land-use, Muara Gembong, shoreline

Judul: Construction of Strongly Optimal Binary Linear Code with Minimum Distance 9 and 11
Abstrak: A binary linear code of length n over q F is a subspace of n q F . A code has three parameters that attached to it, namely length, dimension, and minimum distance. A code with length n, dimension k and minimum distance d is often called [n, k, d ]-code. Usually, when two parameters are given, then we want to find a code that has the best value for the last parameter. Based on Gilbert- Varshamov bound, if a [n, k, d ]-code exists and can not be expanded, we call it a strongly optimal code. In this paper, we construct strongly optimal code with minimum distance 9 and 11. In constructing the code, we created a theorem and algorithm based on Gilbert-Varshamov bound before we implement the algorithm to MAPLE programming language. Because of computational limitations, the program can only construct up to k = 10 for d = 9 and k = 12 for d = 11.
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