Judul: Aspek ekologi perkembangbiakan beo Nias (Gracula religiosa robusta) di Kecamataaan Teluk Dalam, Nias Selatan
Abstrak: Beo Nias merupakan burung endemik di Pulau Nias dan salah satu fauna penjatidiri Sumatera Utara, yang akhir-akhir ini banyak mengalami gangguan baik pada populasi maupun habitatnya. Gangguan pada populasi berbentuk perburuan oleh manusia, sedangkan gangguan terhadap habitatnya berupa penebangan pohon yang dapat menyebabkan rusak atau hilangnya sarang tempat tinggal burung Beo dan semakin berkurangnya pohon penghasil pakan Beo. Tujuan dari penelitian ini adalah untuk mengetahui aspek ekologi perkembangbiakan Beo Nias khususnya sarang, telur dan perkembangan anakan pada pohon tempat bersarang Beo di Kecamatan Teluk Dalam, Nias Selatan. Penelitian dilaksanakan pada bulan Februari April 1994. Pengamatan dilakukan secara terkonsentrasi pada sarang alami dan buatan. Penyajian hasil dilakukan secara deskriptif. ...
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Judul: Kajian kondisi habitat beo Nias (Gracula religiosa robusta) di Pulau Simuk dengan pendekatan potensi pakan dan sarang
Abstrak: Beo nias (Gracula religiosa robusta) dewasa ini mengalami gangguan yang sangat tinggi baik terhadap populasi maupun habitat. Gangguan terhadap populasi berupa penangkapan dan perburuan sehingga populasi turun secara drastis. Berdasarkan PPA (1981) populasi beo nias di Pulau Nias sekitar 5000 ekor dan selanjutnya hasil survey Thohari, dkk. (1996) populasi beo nias di Pulau Nias bagian Selatan berkisar 50 80 ekor. Selain itu gangguan terhadap habitat berupa perambahan hutan yang mengakibatkan hilang atau rusaknya pohon pakan dan pohon sarang beo nias. Secara umum hutan merupakan habitat beo nias, untuk mengetahui keterkaitan kemampuan hutan dalam mendukung kehidupan beo nias, maka dilakukan pengkajian terhadap kondisi habitat beo nias. Penelitian dilakukan di Pulau Simuk Kecamatan Pulau- Pulau Batu Kabupaten Nias selama 2 bulan, mulai dari Bulan September sampai dengan November 1996. Tujuan penelitian adalah untuk mengetahui: kondisi habitat beo nias, karakteristik pohon sarang, karakteristik habitat untuk mencari makan beo nias serta potensi pakan dan sarang. ...
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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