Judul: Studi Bioekologi Habitat Siput Gonggong (Strombus turturella) di Desa Bakit, Teluk Klabat, Kabupaten Bangka Barat, Provinsi Kepulauan Bangka Belitung.
Abstrak: Siput gonggong (Strombus turturella) merupakan salah satu gastropoda dalam famili Strombidae yang banyak ditemukan di perairan dangkal ataupun pasir berlumpur dan banyak dimanfaatkan untuk konsumsi dan dijual. Saat ini permintaan akan daging siput gonggong meningkat dan adanya aktivitas penambangan timah di sekitar wilayah tersebut berpotensi merusak habitat dan menurunkan populasi siput gonggong di alam. Penelitian ini bertujuan untuk mengetahui kondisi bioekologi siput gonggong di perairan Pantai Belembang, Teluk Klabat bagi pengelolaan populasi siput gonggong. Penelitian ini dilaksanakan pada bulan Februari hingga April 2011 di perairan Pantai Belembang, Teluk Klabat, Kabupaten Bangka Barat, Provinsi Kepulauan Bangka Belitung. Penentuan lokasi berdasarkan informasi nelayan yang biasa menangkap dan mengumpulkan siput gonggong. Pengambilan contoh siput gonggong dilakukan dengan transek 1x1 m2 yang peletakkannya berdasarkan penarikkan contoh secara acak sistematik. Analisis data yang digunakan meliputi tipologi substrat, kepadatan, pola sebaran jenis yang dilakukan dengan persamaan densitas dan Indeks Sebaran Morisita, distribusi frekuensi panjang, hubungan panjang cangkang dan bobot total, serta nisbah kelamin. Kualitas perairan Pantai Belembang, Teluk Klabat memiliki kondisi fisika dan kimia perairan relatif masih cukup baik dengan suhu perairan berkisar antara 28- 29,7 °C, salinitas berkisar antara 31,0-33,0 ‰, derajat keasaman (pH) berkisar antara 7-8, oksigen terlarut (DO) berkisar antara 5,26-6,67 mg/l, Total Padatan Tersuspensi (TSS) berkisar antara 7-33 mg/l, kekeruhan berkisar antara 2,5-10 NTU, kandungan logam Pb dalam air berkisar antara 0,000-0,012 mg/l, dan substrat berupa pasir hingga pasir berlempung. Pola sebaran siput gonggong adalah mengelompok dengan kepadatan siput gonggong berkisar antara 14-23 ind/20 m2. Ukuran siput gonggong secara keseluruhan berkisar antara 46,80-60,95 mm dengan modus frekuensi panjang pada ukuran 52,11-53,87 mm pada betina dan ukuran 50,34-52,10 mm pada jantan. Rasio kelamin siput antara jantan dan betina adalah ideal. Pola pertumbuhan total siput gonggong dilokasi penelitian menunjukkan pola pertumbuhan allometrik negatif, dimana individu siput gonggong yang ditemukan cenderung memanjang dengan persamaan pertumbuhan W=0,006 L2,076. Strategi pengelolaan siput gonggong di perairan Pantai Belembang, Teluk Klabat antara lain adalah peningkatan kualitas perairan dan substrat dengan mengatur frekuensi penambangan timah yang limbahnya berpotensi menutupi substrat tempat hidup siput gonggong. Selain itu membuat instalasi pengolahan limbah timah untuk mencegah beban pencemar yang masuk ke perairan. Pengadaaan penyuluhan kepada masyarakat untuk tidak menangkap siput gonggong yang berukuran lebih dari 53,87 mm, sehingga dapat memberikan kesempatan siput untuk memijah dan berkembangbiak. Mengadakan pergiliran pemungutan siput gonggong berdasarkan tempat pada waktu surut yang berlainan.
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Judul: Sebaran Spasial dan Potensi Reproduksi Populasi Siput Gonggong (Strombus turturela) di Teluk Klabat Bangka-Belitung
Abstrak: Dog conch (Strombus turturella) as a popular food source has undergone a rapid decreasing in population because of habitat destruction. A research has been done in Klabat bay, Bangka Belitung in 3 months to assess habitat characteristics and individual spatial distribution using PCA and CA. Based on environmental biophysical and chemical parameter, spatial distribution consists of cluster formed by temperatur, pH, DO, and sand; cluster formed by depth and turbidity; and cluster formed by salinity, TOM, and clay. Spatial distribution based on shell-size consists of small cluster (20,39 mm - 38,53 mm); medium cluster (38,54mm - 56,68 mm); and big cluster (56,69 mm - 78,34 mm). Length-weight analysis result shows a negative allometric growth pattern (b= 2,787). Furthermore, spatial distribution based on gonad maturity index consists of GMI 0 formed by DO, turbidity, depth, temperatur, pH, and sand; GMI I formed by temperatur, DO, pH, sand, salinity, TOM, clay and mud; and GMI III formed by salinity, TOM, clay and mud, depth and turbidity. Spawning pattern analysis shows that conch spawning season reach its peak during May and June annually.
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Judul: Algorithm construction of HLI hash function
Abstrak: Cryptography is a study of mathematical techniques related to aspects of information security regarding on confidentiality, data integrity, entity authentication, and data origin authentication. Data integrity is a service, which is associated with the conversion of data carried out by unauthorized parties. To maintain data integrity, one can use hash functions. An hash function is a computationally efficient function to map an arbitrary length bitstring to a fixed length bitstring called as hash value. The use of hash function in maintaining the information integrity and authentication is in digital signatures, virus protection, and software distribution. Illustration of the hash function in the integrity and authentication of information that is emailed as follow. The sender sends the information and hash value to the recipient. If the hash value of the information is equal to the hash value that is sent by the sender, then information has not been changed. Otherwise the information has been changed. An hash function has two properties, one way and collision resistance. An hash function is called one way if it is computationally infeasible to find any input such that when given any hash value . Meanwhile an hash function is called collision resistant if it is computationally infeasible to find any two inputs where such that . The purpose of this study is to construct a HLI hash function algorithm, to analyze the speed and security of the hash functions as a results of construction. Furthermore, it is to compare it with SWIFFT. Hash function is constructed based on the result of algebraic operations on modular polynomial ringwith . Modular polynomial ring noted as is a set of all polynomials of degree at most with coefficients in . can be represented as a set of integer vector of modulo in dimension . So, it is simple to implement in a computer. In vector operations, is lattice . Furthermore, alattice that is defined from certain polynomial ring is called ideal lattice. HLI hash function is consists of addition and multiplication algorithm in the ring. Addition algorithm consists of sumation operations of modulo and multiplication consists of multiplication operations of modulo . Generally, algorithm of HLI hash function consists of multiplication operations of modulo and addition operations of modulo . However, if the input is binary number then multiplication algorithm only consists of multiplication operation of modulo , so algorithm of HLI hash function consists of multiplication operations of modulo and addtion operations of modulo . An hash function is secured if it has two properties, i.e., one way and collision resistance. HLI hash function hash is one way, it is following the proof of Micciancio. It is has collision resistant because of polynomial is irreducible over and monic. Moreover, it is proved that for every unit vector , the vector is small vector. If the input of hash function is a binary number then HLI hash function only involves addition operations of modulo . So the time that used almost same with SWIFFT. The excellence of HLI hash function is the key size smaller than SWIFFT. This effect on
Keyword: hash function, modular polynomial ring, lattice