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: Characteristics of the Hawksbill Turtle (Eretmochelys imbricata) Nesting Beach on Kepayang Island, Bangka Belitung.
Abstrak: Populasi penyu sisik di alam saat ini mengalami penurunan, terutama dikarenakan oleh faktor alami dan faktor antropogenik. Penelitian ini bertujuan mengetahui karakteristik habitat peneluran penyu sisik (Eretmochelys imbricata) di Pulau Kepayang pada tahun 2019. Parameter yang diukur kemudian dianalisis menggunakan metode Principal Components Analysis (PCA) dan Correspondence Analysis (CA). Jumlah telur terbanyak terdapat di lokasi 3 yaitu 507 butir, sementara jumlah terendah berada di lokasi 2 sejumlah 355 butir. Karakteristik habitat peneluran penyu sisik yaitu tipe pantai dengan kemiringan berkisar 2.16-3.81°, lebar pantai berkisar 8.4-10.52 m, panjang pantai berkisar 460-515 m. Fraksi sedimen didominasi oleh pasir sedang dan pasir sangat kasar. Kerapatan vegetasi termasuk dalam kategori baik. Sarang 4, 5 dan 6 dipengaruhi oleh lebar pantai dan pasir sangat halus sedangkan sarang 7,8,9 dan 10 dipengaruhi panjang pantai, kemiringan pantai dan pasir sangat kasar. Hasil analisis CA menunjukkan bahwa vegetasi Pcem, Pbut, Paka, Tbut dan Tsim memiliki hubungan yang erat dengan jumlah telur yang banyak 3(133-145). Sementara vegetasi lainnya memiliki korelasi yang erat dengan telur yang berjumlah sedang 2(121-132). Kata kunci: karakteristik lingkungan, penyu sisik, Pulau Kepayang, vegetasi, The hawksbill population in the wild is currently declining, mainly due to natural factors and anthropogenic factors. This study aims to determine the characteristics of the hawksbill nesting habitat (Eretmochelys imbricata) in Kepayang Island in 2019. The parameters measured then analyzed by Principal Components Analysis (PCA) and Correspondence Analysis (CA) methods. The highest number of turtle eggs was found in location 3 with a total of 507 eggs, while the lowest number was in location 2 with 355 eggs. The characteristics of the hawksbill nesting habitat include a sloping type of beach with 2.16-3.81°, a beach width ranging from 8.4-10.52 m, a beach length ranging from 460-515 m. The sediment fraction is dominated by medium and very coarse sand. The vegetation density is in the good category. Whereas nests 4, 5 and 6 are influenced by the characteristics of beach width, very fine sand and nests 7,8,9 and 10 are affected by beach length, beach slope and very coarse sand. The results of the CA analysis showed that the Pcem, Pbut, Paka, Tbut and Tsim vegetation had a close relationship with a large number of eggs 3(133-145). Meanwhile, the other vegetations had a close correlation with the medium number of eggs 2(121-132). Keywords: environmental characteristics, hawksbill turtle, Kepayang Island, vegetation
Keyword: environmental characteristics, hawksbill turtle, Kepayang Island, vegetation

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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