Judul: Karakteristik biota karang dan ikan karang penyusun ekosistem terumbu karang di Gosong Pabelokan Kepulauan Seribu Jakarta
Abstrak: Penelitian ini dilakukan di Gosong Pabelokan, Teluk Jakarta. pada bulan April- Juni 1997. Penelitian ini be1iujuan untuk mengetahui kondisi ekosistern terumbu karang dan ikan karang serta parameter fisika-kimia yang mendukung terumbu karang. Metode yang digunakan untuk pengamatan terumbu karang adalah metode transek garis sepanjang 100 meter, pada kedalaman 3 dan 10 meter. Komponen dasar yang diamati digolongkan berdasarkan Structural Analysis of Life Form (English et al., 1994). Nilai penutupan yang di peroleh di dasarkan pada persentase penutupan yang dicakup oleh transek garis. Pengamatan ikan karang dilakukan dengan metode pencacahan langsung (Visual census). Data yang diperoleh dari hasil penelitian dianalisis berdasarkan persentase penutupan biota karang, kelimpahan jenis ikan karang, indeks keanekaragaman (H'), indeks keseragarnan (E), dan indeks dominansi (C).
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Judul: Studi Komunitas Ikan Karang Di Gugusan Pulau Pari Kepulauan Seribu Jakarta Utara
Abstrak: Penelitian ini bertujuan untuk mendapatkan gambaran struktur komunitas ikan terutama mengenai komposisi jenis, kemelimpahan relatif, dominansi, keanekaragaman, keseragaman, asosiasi dan kemiripan komunitas ikan yang hidup di terumbu karang di gugusan Pulau Pari, Kepulauan Seribu, Jakarta Utara. Penelitian ini dilaksanakan pada tanggal 28 Juli sampai 11 September 1986. Pengambilan contoh ikan dengan menggunakan alat tangkap bubu untuk habitat karang dengan lama pengoperasian +48 jam, alat tangkap jaring insang untuk habitat goha dan jaring cekek untuk habitat padang lamun, kedua jaring ini dioperasikan + 12 jam dari jam 18.00 06.00. Masing-masing enam stasiun untuk tiap habitat. Dari hasil pengamatan pada 18 stasiun, jumlah ikan yang tetangkap sebanyak 439 ekor dari 30 famili. Dari jumlah tersebut famili ikan Siganidae merupakan ikan yang terbanyak (80 ekor), kemudian diikuti oleh famili Scaridae, Pomacentridae, Labridae, dan Lethrinidae. Sedangkan kemelimpahan relatif tertinggi adalah ikan kea-kea (Siganus virgatus) dengan nilai 13,7 persen. ...
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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