Judul: Preferensi Habitat Spons di Pesisir Pulau Pramuka, Kepulauan Seribu, DKI Jakarta
Abstrak: Marine sponges live at several habitats, such as sand, dead coral, rock and any media which has hard structure. The purposes of this study were to study sponges community structure and determine the habitat preferences of sponges’ at Pramuka Island coast, Kepulauan Seribu. This study was conducted in August to November 2014 at three sites representing each habitats; in The east of Pramuka Island for seagrass (SL1) and mangrove (SM1), Southeast (SL2 and SM2), and South (SL3 and SM3). Sponge observation and sample collection were done by 30 m belt transect method placed along the coastline with the radius of 1 m, while to calculate the density and type of seagrass and mangrove closure using quadratic transect size of 0.5 x 0.5 m2 and 5 x 5 m2. The result of this study showed that sponges had a variety of 16 species of 9 orders, 14 families, and 16 genera. Seven species of sponge was observed at seagrass habitat, while four species at mangrove and five at both habitats. Plakinastrella onkodes was the most common species observed in seagrass, Callyspongia pallida was the most common species observed in mangrove.
Keyword: Bogor Agricultural University (IPB), Pramuka Island, mangrove, seagrass, sponges, community structure

Judul: Hubungan Nudibranch dan Substrat di Perairan Pulau Pramuka, Kepulauan Seribu, DKI Jakarta
Abstrak: Substrat dasar perairan Pulau Pramuka berperan penting dalam kehidupan nudibranch sebagai hewan gastropoda, yaitu sebagai media tempat menempel dan berjalan, sekaligus tempat mencari makan. Penelitian ini bertujuan untuk mengetahui hubungan nudibranch dan substrat dasar perairan di Pulau Pramuka, Kepulauan Seribu. Pengambilan data nudibranch dilakukan pada lima stasiun dengan penyelaman menggunakan metode Belt Transect, sedangkan data substrat menggunakan metode transek kuadrat. Analisis data substrat mencakup tiga tipe yaitu tutupan substrat per stasiun, tutupan substrat di area sekitar nudibranch, dan substrat tempat menempel nudibranch. Analisis data nudibranch mencakup komposisi spesies, kepadatan, dan keanekaragaman. Nudibranch yang ditemukan pada penelitian ini berjumlah 73 individu yang termasuk ke dalam tiga famili yaitu Phyllidiidae, Facelinidae dan Flabellinidae. Stasiun dengan tutupan karang hidup lebih tinggi memiliki nilai kepadatan dan keanekaragaman nudibranch yang lebih tinggi. Substrat sebagai habitat nudibranch didominasi oleh pasir dan rubble sedangkan substrat tempat menempel nudibranch didominasi oleh substrat karang mati yang tertutup alga.
Keyword: coral reef, dead coral, nudibranch, sponge, substrate

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