Judul: Pemetaan Karakteristik Biofisik Perairan Laut Dangkal Pulau Pramuka dan Pulau Karya
Abstrak: Biofisik perairan adalah suatu komponen yang terdiri dari komponen biotik dan abiotic di perairan dangkal maupun perairan dalam. Tujuan dari penelitian ini adalah untuk memetakan karakteristik biofisik perairan Laut Dangkal Pulau Pramuka dan Pulau Karya, Kepulauan Seribu. Penelitian ini dilakukan dengan survei lapangan dan pengolahan citra Sentinel 2-A. Survei lapangan dilakukan dengan metode Manta Tow. Tahapan koreksi citra yang dilakukan adalah koreksi radiometrik dan geometrik. Metode klasifikasi citra yang digunakan adalah klasifikasi unsupervised. Hasil dari penelitian menunjukkan bahwa karakteristik biofisik di Pulau Karya dan Pulau Pramuka dapat dipetakan. Kedalaman perairan dangkal di Pulau Pramuka berkisar antara 2 m – 7.5 m, kecepatan arus berkisar antara 6.8 cm/s – 10 cm/s, kecerahan perairan 100%, jumlah jenis lifeform berkisar antara 2 – 5 jenis, dan kekayaan jenis ikan berkisar antara 1 – 11 jenis.
Keyword: biofisik, pemetaan, Pulau Karya, Pulau Pramuka

Judul: Keanekaragaman Meiofauna Berdasarkan Karakteristik Substrat Padang Lamun di Perairan Pulau Pramuka, Kepulauan Seribu
Abstrak: Meiofauna merupakan biota asosiatif ekosistem padang lamun yang berukuran 0.063–1 mm dan hidup secara interstisial dalam substrat dasar. Penelitian ini bertujuan mengetahui keanekaragaman meiofauna dan keterkaitanya dengan karakteristik substrat padang lamun di Pulau Pramuka, Kepulauan Seribu. Penelitian dilakukan pada tiga stasiun, di mana pada masing-masing stasiun ditetapkan 9 plot pengambilan sampel meiofauna dan di dalam setiap plot terdapat 5 subplot. Pengambilan sampel meiofauna dilakukan menggunakan tabung paralon (ø: 5 cm; tinggi: 30 cm) yang dibenamkan dalam substrat. Meiofauna yang ditemukan pada lokasi penelitian terdiri dari 6 filum, 8 kelas, 17 ordo, 31 famili, dan 35 genera. Filum yang memiliki kelimpahan tertinggi adalah Nematoda. Pada lokasi penelitian, meiofauna lebih banyak ditemukan pada substrat pasir yang memiliki ukuran butiran halus dan mengandung bahan organik. Meiofauna umumnya ditemukan pada ekosistem lamun dengan jenis dominan Thalassia hemprichii, Cymodocea serrulata, dan Enhalus acoroides.
Keyword: keanekaragaman, lamun, meiofauna, Pulau Pramuka, substrat

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