Judul: Kemampuan Tanah Menahan Air dan Kepekaan Erosi Tanah Pada Berbagai Umur Pembukaan Lahan Alang-Alang di Daerah Transmigrasi Barubara Martapura, Sumatera Selatan
Abstrak: Penelitian ini bertujuan untuh melihat pengaruh umur pembukaan lahan terhadap kemampuan tanah menahan air, menetapkan nilai kepekaan erosi tanah dengan menggunakan nomograf (Wischmeier, Johnson dan Cross, 1971) dan melihat hubungannya dengan umur pembukaan lahan, dan menduga besarnya erosi yang dan terjadi dengan sistim usahatani gang ada di daerah Baturaja Bartapura, Sumatera Selatan.
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Judul: Laju infiltrasi tanah pada berbagai umur pembukaan dan sistim pengelolaan lahan alang-alang dari podsolik merah kuning daerah transmigrasi Baturaja - Martapura Sumatera Selatan
Abstrak: Untuk menghindari terjadinya kerusakan tanah akibat pembukaan lahan yang terus-menerus dan penggunaannya secara maksimal, maka perlu menggunakan kaedah-kaedah konservasi tanah dan air dalam mengelola lahan tersebut sebagai lahan pertanian. Pada dasarnya konservasi tanah dan air adalah memperbesar laju infiltrasi dan memperkecil aliran permukaan. Tinggi rendahnya laju infiltrasi sangat berpengaruh terhadap simpanan air bawah tanah dan laju penyediaan air untuk tanaman. Oleh karena itu kemampuan tanah untuk menginfiltrasikan air perlu ditingkatkan dan dipertahan- kan. Metode pembukaan lahan dan sistim pengelolaan lahan selanjutnya yang dilakukan petani, dapat mempengaruhi tinggi rendahnya laju infiltrasi lahan tersebut. Tujuan penelitian ini adalah untuk mengetahui pengaruh umur pembukaan lahan alang-alang terhadap laju infiltrasi tanah, dan untuk membantu usaha mencari keserasi an dan keseimbangan antara metode pembukaan lahan dan pengelolaan lahan selanjutnya, sehingga produktivitas tanah dapat ditingkatkan dan dipertahankan. Pengukuran infiltrasi dilakukan pada tujuh tingkat umur pembukaan lahan alang- alang di Daerah Transmigrasi Baturaja-Martapura Sumatera Selatan, pada jenis tanah Podsolik Merah Kuning, kemiring- an lereng, dan vegetasi yang relatif sama. Berdasarkan penelitian ini, laju infiltrasi awal dari lokasi-lokasi pengamatan bervariasi dari 33.4 cm/jam sampai 169.1 cm/jam. Hal ini terjadi karena adanya perbedaan kadar air tanah sebelum dilakukan pengukuran, dan perbedaan sifat-sifat fisik tanah dari lokasi-lokasi pengamatan tersebut…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