Judul: Habitat Bertelur dan Upaya Konservasi Penyu Sisik (Eretmochelys imbricata, Linnaeus 1766) di Pulau Lengkuas, Kabupaten Belitung
Abstrak: Penyu sisik merupakan salah satu satwa liar yang dilindungi menurut Peraturan Pemerintah Republik Indonesia Nomor 7 Tahun 1999. Pemanfaatan terhadap karapas, daging, dan telur penyu sisik di Indonesia sangat tinggi sehingga upaya konservasi penyu sisik perlu dilakukan. Habitat penyu sisik di Kabupaten Belitung dapat ditemukan di Pulau Lengkuas. Penelitian ini penting dilakukan untuk mengidentifikasi kondisi habitat, keberhasilan penetasan, dan upaya konservasi penyu sisik di Belitung. Pengambilan data dilakukan secara observasi langsung dan wawancara, pada bulan Maret hingga Mei 2020. Analisis data dilakukan secara deskriptif. Pulau Lengkuas memiliki kondisi habitat dengan kelerengan pantai antara 12°-30°, panjang garis pantai antara 11 m – 159,3 m saat surut dan 20 m – 108,7 m saat pasang, lebar garis pantai antara 20 m – 67,2 m saat surut dan 2 m – 37,5 m saat pasang, keasaman tanah normal, substrat berupa pasir. Penangkaran penyu sisik di Pulau Lengkuas memiliki tingkat keberhasilan tetas telur sebesar 61%. Pemanfaatan penyu sisik oleh masyarakat Belitung umumnya berupa pengambilan telur penyu untuk dijual. Sedangkan upaya konservasi yang dilakukan berupa sosialisasi dan peringatan kepada penjual dan pembeli., Hawksbill turtle is one of the protected wild animals according to Government Regulation of the Republic of Indonesia Number 7 of 1999. Utilization of the carapace, meat, and eggs of hawksbill turtles in Indonesia is very high so that hawksbill turtle conservation efforts need to be carried out. Hawksbill turtle habitat in Belitung can be found on Lengkuas Island. This research is important to do to identify habitat conditions, hatching success, and conservation efforts of hawksbill turtles in Belitung. Data collection was carried out by direct observation and interviews, from March to May 2020. Data analysis was carried out descriptively. Lengkuas Island has habitat conditions with coastal slopes between 12°-30°, coastline lengths between 11 m – 159,3 m at low tide and 20 m – 108,7 m at high tide, coastline width between 20 m – 67,2 m at low tide and 2 m – 37,5 m at high tide, normal soil acidity, substrate in the form of sand. Hawksbill turtle breeding on Lengkuas Island has a success rate of hatching eggs of 61%. The use of hawksbill turtles by the Belitung people is generally in the form of taking turtle eggs for sale. Meanwhile, conservation efforts are carried out in the form of socialization and warnings to sellers and buyers.
Keyword: conservation, hawksbill turtle, lengkuas island, nesting habitat

Judul: Sebaran Lokasi Peneluran Penyu Sisik (Eretmochelys imbricata) di Taman Nasional Kepulauan Seribu
Abstrak: Populasi penyu sisik berpotensi mengalami penurunan 80% sejak dua dekade lalu dan masuk dalam kategori ‘Critically Endangered (CR)’ pada daftar IUCN. Penelitian ini bertujuan menginventarisasi sebaran lokasi peneluran penyu sisik, mengeksplorasi karakteristik habitat dan faktor yang mempengaruhi kegiatan peneluran penyu sisik di Taman Nasional Kepulauan Seribu. Penelitian dilakukan pada bulan Maret 2023 hingga Juni 2023 dengan survei lapangan pada ketiga seksi pengelolaan di Taman Nasional Kepulauan Seribu. Pengambilan titik lokasi menggunakan metode survei deskriptif analitik. Berdasarkan hasil penelitian ditemukan bahwa vegetasi yang mendominasi adalah jenis rumput Ischaemum muticum dan cemara Casuarina equisetifolia. Kemiringan pantai di setiap pulau yang dikunjungi berkisar 4,1º-5,4º. Fraksi pasir didominansi kategori sedang dan halus dengan ukuran 0,2 mm – 1 mm. Terjadi perubahan pola titik sebaran peneluran penyu sisik di Taman Nasional Kepulauan Seribu setiap tahunnya. Ditemukan lima pulau peneluran yakni Yu Barat, Yu Timur, Peteloran Timur, Pramuka, dan Kayu Angin Bira. Sebanyak 7 dari 10 sarang yang ditemukan terletak pada wilayah zona inti yang memiliki karakteristik cukup sesuai bagi penyu sisik untuk melakukan peneluran. Kegiatan pariwisata di sekitar Taman Nasional kepulauan Seribu memiliki pengaruh yang nyata terhadap kegiatan peneluran penyu sisik yang ada di kawasan ini., The population of hawksbill turtles potentially declined by 80% two decades ago, categorizing them as 'Critically Endangered (CR)' on the IUCN list. This research aims to inventory the distribution of hawksbill turtle nesting locations, explore changes in habitat characteristics and determine influencing factors hawksbill turtle nesting activities in Thousand Islands National Park. Research period takes place from March 2023 to June 2023, involving field surveys in three management sections in Thousand Islands National Park. The location points retrieval using analytical descriptive survey method. Results of the study, the dominating vegetation was Ischaemum muticum and Casuarina equisetifolia. The slope of the beach on each visited island ranges from 4,1º-5,4º. The sand fraction is dominated by medium and fine categories with a size of 0,2 mm – 1 mm. Each year the pattern of distribution points of turtles nesting has not been changed dramatically in Thousand Islands National Park. Ten nests in five nesting islands were founded: West Yu, East Yu, East Peteloran, Pramuka, and Kayu Angin Bira. Seven out of ten nests were in the core zone, where the habitat was more decent. Tourism activities were suspected to have a negative impact on turtle nesting activities in this region.
Keyword: nesting distribution, hawksbill turtle, thousand island national park

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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