Judul: Struktur Komunitas Makrozoobentos di Perairan Sungai Banjaran dan Sungai Kranji Kabupaten Banyumas, Jawa Tengah
Abstrak: Sungai Banjaran dan Sungai Kranji merupakan sungai yang melintasi kota Purwokerto. Daerah ahan Sungai Banjaran dau Sungai Kranji yaitu melintasi daerah perladangan, sawah dan pemukiman penduduk. Setelah masuk Purwokerto, baik Sungai Banjaran maupun Sungai Kranji banyak dimanfaatkan untuk tempat pembuangan sampah dan limbah rumah tangga. Hal ini akan menyebabkan menurunnya kualitas perakan Suugai Banjaran dan Sungai Kranji. Penelitian ini bertujuan untuk mengetahui struktur komunitas makrozoobentos dan faktor-faktor lingkungn yaug mempengaruhi kehidupan organisme tersebut serta mengetahui organisme tertentu yang mungkin dapat dijadikan spesies indikator pada kondisi lingkungan (parameter) tertentu.
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Judul: Struktur Komunitas Makrozoobentos dan Keterkaitannya Dengan Karakteristik Sedimen di Perairan Muara Sungai Bantan Tengah, Bengkalis
Abstrak: Perairan muara sungai Bantan Tengah terletak di Pulau Bengkalis, Kabupaten Bengkalis, Propinsi Riau. Sungai Bantan Tengah merupakan salah satu sungai yang mengalir di Pulau Bengkalis. Di daerah muara sungai ini berkembang kegiatan pemeliharaan ikan dalam keramba jaring apung yang jumlahnya mencapai ratusan unit. Dengan bertambahnya jumlah ini dikuatirkan akan mem-berikan dampak terhadap kondisi lingkungan perairan ini di masa mendatang, yaitu berupa peningkatan pencemaran organik. Tujuan dari penelitian ini adalah untuk mengkaji struktur komunitas makrozoobentos sebagai indikator kondisi perairan dan menentukan keterkaitan antara struktur komunitas makrozoobentos dan karakteristik sedimen muara sungai Bantan Tengah. Hasil penelitian ini diharapkan dapat memperkaya informasi mengenai struktur makrozoobentos dan kondisi perairan serta tentang faktor-faktor yang mempengaruhi distribusi makrozoobentos. Penelitian ini dilakukan di perairan muara sungai Bantan Tengah yang mencakup 11 stasiun pengamatan. Penelitian dilaksanakan dari awal bulan Maret 1997 sampai akhir bulan Mei 1997. Karaktedstik fisika-kimia air yang diukur adalah kedalaman perairan, suhu, kecerahan, kecepatan arus, salinitas, oksigen terlarut, pH, nitrat dan ortofosfat. Sementara itu karakteristik sedimen dasar yang diukur adalah derajat keasaman (pl-I), redokspotensial (Eh), organik total, C- organik, fraksi sedimen (pasir, lumpur dan liat), nitrat dan ortofosfat. Parameter biologi yang diamati adalah struktur komunitas makrozoobentos. dst ...
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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