Judul: Kondisi Terumbu Karang di Perairan Distrik Seget, Kabupaten Sorong, Provinsi Papua Barat Daya
Abstrak: Terumbu karang merupakan ekosistem yang sangat penting dan banyak ditemukan di wilayah tropis seperti Indonesia, termasuk di Perairan Distrik Seget, Kabupaten Sorong, Papua Barat Daya. Belum pernah ada penelitian mengenai terumbu karang di perairan tersebut. Ekosistem terumbu karang mempunyai arti yang sangat penting bagi kehidupan manusia, baik dari segi ekonomi, ekologi maupun sebagai penunjang kegiatan rekreasi laut karena keindahannya. Ekosistem terumbu karang sangat rentan terhadap perubahan lingkungan yang terjadi seperti tingkat kejernihan air, salinitas, sedimentasi, dan suhu permukaan laut. Penelitian ini bertujuan untuk mengetahui kondisi terumbu karang yang ada di Perairan Distrik Seget, Kabupaten Sorong, Provinsi Papua Barat Daya. Metode yyang digunakan adalah Underwater Photo Transect dengan ukuran 58 cm x 44 cm. Berdasarkan pengamatan yang dilakukan di lokasi penelitian, diketahui bahwa kondisi tutupan karang keras pada lokasi penelitian masuk ke dalam kategori buruk hingga baik dengan nilai tutupan kategori berkisar antara 5,25%–61,81%. Genus Porites (235 koloni) merupakan genus karang keras yang paling umum, sedangkan Genus Pocillopora (satu koloni) memiliki sebaran yang paling rendah
Keyword: category, coral reefs, cover, seget district, underwater photo transek

Judul: Studi Kondisi Terumbu Karang di Perairan Bagian Utara dan Selatan Kepulauan Seribu, DKI Jakarta
Abstrak: Ekosistem Terumbu Karang merupakan ekosistem dinamis yang tidak tahan terhadap gangguan antropogenik. Ekosistem ini terus menerus berubah seiring dengan adanya adaptasi terhadap stress. Aktivitas manusia dan kondisi alam merupakan faktor yang mempengaruhi perubahan kondisi terumbu karang dalam suatu wilayah. Tujuan penelitian ini adalah mengetahui kondisi terkini terumbu karang di daerah perairan wilayah Kabupaten Administrasi Kepulauan Seribu bagian Utara dan bagian Selatan, DKI Jakarta. Penelitian ini dilaksanakan pada tanggal 29-31 Mei 2014 dengan menggunakan metode Line Intercept Transect (LIT) sepanjang 50 m dengan satu kali ulangan. Hasil penelitian yang dilakukan menunjukkan bahwa tutupan karang keras pada site Kepulauan Seribu bagian utara memiliki presentase tertinggi sebanyak 63.86% (kategori baik) yang terdapat pada site Karang Congkak Alami, dan nilai presentase terendah sebanyak 35.49% (kategori rendah) terdapat pada site Belanda. Sedangkan tutupan karang keras pada site Kepulauan Seribu bagian selatan memiliki nilai presentase tertinggi sebanyak 75% (kategori sangat baik) yang terdapat pada site Utara Tengah, dan presentase terendah dengan kategori buruk terdapat pada site Pulau Tidung Besar (7.46%) dan Pulau Tidung Kecil (9,4%).
Keyword: Ecosystem, Coral reefs, Coral coverage of the Seribu Island, Dynamic ecosystem, Marine science technology, Tutupan karang keras, Antropogenik, Hard coral

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