Judul: Komunitas ikan Karang Pada Ekosistem Temmbu Karang Ponton Bodong dan Toyapakeh di Perairan Nusa Penida, Bali
Abstrak: Penelitian ini bertujuan untuk memperoleh gambaran terhadap kondisi ikan karang di sekitar Ponton Bodong dan Ponton Toyapakeh, Nusa Penida, Bali. Parameter yang eliukur untuk mendukung peuelitian ini adalah persentase penutupan karang, kelimpahan ikan karang, komposisi jenis-jenis ikan karang, struktur komunitas ikan karang, pengelompokkan dan hubungan bentuk-bentuk pertumbuhan karang dengan kelimpahan elan jenis ikan karang.
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Judul: Analisa struktur dan kondisi komunitas ikan karang pada ekosistem terumbu karang di Perairan Pesisir Utara Pulau Nusa Penida, Bali
Abstrak: Ikan karang merupakan organisme yang memiliki jumlah terbanyak dan merupakan penyokong hubungan yang ada dalam ekosistem terumbu karang (Nybakken, 1988). Dengan demikian antara terumbu karang dan ikan karang memiliki hubungan erat dimana keberadaan dan kondisi lerumbu karang sangat mempengaruhi kekayaan dan keanekaragaman ikan karang didalamnya Pulau Nusa Penida merupakan salah satu daerah tujuan wisata dan saat ini sedang dikembangkan menjadi kawasan wisata bahan sehingga dikhawatirkan kegiatan panwisata tersebut dapat menimbulkan perubahan kondisi ekosistem terumbu karang dan komunitas ikan karang di kawasan Nusa Penida. Penelitian ini bertujuan untuk melihat profil terumbu kerang berdasarkan persen penutupan lifeform karang dan asosiasinya dengan ikan karang, menghitung struktur komunitas ikan karang yang terdapat pada terumbu karang tersebut dan mengkaji kondisi komunitas ikan karang. Penelitian dilakukan di Pulau Nusa Penida pada bulan Mei 2000 dengan 4 stasiun pengamatan yang terdapat di sepanjang pesisir Utara Pulau Nusa Penlda yaitu stasiun Bodong (stasiun 1), Tanah Bias (stasiun 2), Prapat (stasiun 3) dan Tanjung Daiam (stasiun 4). Terumbu karang di semua stasiun pengamatan terrnasuk terumbu karang tepi (fringing ree~ dan terrnasuk daerah terlindung angin (leewarcf). Kondisi perairan Utara Pulau Nusa Penida berdasarkan hasil pengamatan di keempat stasiun menunjukkan bahwa perairan tersebut masih tergolong baik dan sesuai untuk pertumbuhan terumbu karang dimana suhu berkisar antara 29,0-30,OoC, salinitas antara 32,033,00/ 00, kecerahan 100% dan mempunyai kecepatan arus perrnllkaan yang berkisar antara 0,54-1,10 m/dtk. Pencatatan data karang berdasarkan bentuk pertumbuhan (lifeform) karang menggllnakan metode transek gans (Line Transect Methocf) dengan menggunakan rollmeter iii sepanjang 50 meter dan diletakkan sejajar garis pantai pada dua kedalaman yaitu 3 meter dan 10 meter. Pencatatan data ikan karang dilakukan dengan menggunakan metode sensus visual.
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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