Judul: Ekostruktur dan sebaran spasial komunitas gastropoda di kawasan pasang surut Teluk Manado, Sulawesi Utara
Abstrak: Tujuan penelitian ini ialah mendeskripsikan ekostruktur komunitas dan sebaran spasial komunitas gastropoda secara umum di kawasan pasang surut serta keterkaitan antara gastropoda dengan karakteristik lingkungannya. Komunitas gastropoda di kawasan pasang surut Teluk Manado temyata bervariasi dalam komposisi, kepadatan dan keanekaragaman per stasiun. Spesies gastropoda yang ditemukan di kawasan pasang surut Teluk Manado terdiri dari 63 spesies (35 genera) masing-masing terdiri dari ordo Archaeogastropoda 10 spesies, ordo Mesogastropoda 18 spesies dan ordo Neogastropoda 35 spesies. Kepadatan total gatropoda masing-masing stasiun pengamatan 6 47 individu/m2 dengan keanekaragaman berkisar antara 2,067-2,809 diklasifikasikan sebagai perairan dengan pencemaran ringan.
Keyword: Ecostructure, sebaran spasial

Judul: Struktur komunitas penyebaran gastropoda di Perairan Pelabuhan Ratu, Sukabumi, Jawa Barat dan Pelabuhan Teluk Bayur, Padang, Sumatera Barat
Abstrak: Pelabuhan Ratu dan Pelabuhan Teluk Bayur merupakan daerah mempunyai kecenderungan adanya penurunan kualitas perairan sehubungan dengan kegiatan pelabuhan kapal laut, pelabuhan perikanan, industri kapal/perahu, lalulintas kapal/perahu, dan pariwisata. Akibat kegiatan tersebut diduga akan mempengaruhi kualitas perairan. Penurunan kulitas perairan pada akhirnya akan menimbulkan gangguan terhadap komunitas organisme dilingkungan perairan tersebut. Penelitian ini bertujan untuk mengetahui struktur komunitas gastropo- da dengan melihat kepadatan, komposisi jenis dan pola penyebaran sebagai dasar untuk mengetahui kondisi lingkungan di kedua lokasi tersebut. Selain itu mengetahui faktor-faktor lingkungan yang mempengaruhi keberadaannya. Stasiun pengambilan contoh ditentukan berdasarkan adanya kegiatan pelabuhan kapal, pelabuhan perikanan, industri kapal/perahu, lalulintas kapal/perahu, dan pariwisata yang diduga memberi sumbangan bahan pencemar pada perairan teluk. Parameter lingkungan yang fisika kimia yang meliputi pasang surut, suhu, salinitas, tipe subtrat, C-Organik, dan logam Cu dan Sn, sedangkan parameter biologi adalah gastropoda. Analisis parameter fisika kimia dilakukan secara deskriptif berdasarkan sebarannya, sedangkan analisis parameter biologis dilakukan dengan menghitung kepadatan, indeks keanekaragaman, indeks keseragaman, indeks dominansi, pola sebaran, indeks similaritas Sorensen dan analisis suksesi ekosistem Frontier. Sedangkan untuk melihat keterkaitan antara parameter lingkungan yang ada dengan kepadatan gastropoda digunakan analisa regresi linier berganda (Steel dan Torrie, 1989)....
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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