Judul: Perubahan karbon organik dan nitrogen total tanah akibat perlakuan pupuk organik pada budi daya sayuran organik
Abstrak: Pertanian organik merupakan sistem pertanian yang menekankan penggunaan bahan organik seperti kotoran ternak dan sisa tanaman sebagai pengganti pupuk kimia serta upaya meminimalkan pemakaian pestisida sintesik yang memberikan dampak kerusakan terhadap lingkungan. Keberadaan nitrogen dan karbon dalam tanah berperan penting dalam menjaga mutu kesuburan tanah maupun tanaman, sehingga perlu dilakukan pengukuran terhadap kandungan nitrogen dan karbon dalam tanah. Kandungan karbon dan nitrogen pada tanah diukur menggunakan spektofotometer sinar tampak. Kadar C organik diukur berdasarkan metode analisis Kurmies pada panjang gelombang 561 nm, sedangkan untuk pengukuran kadar nitrogen digunakan metode Kjeldahl pada panjang gelombang 636 nm. Rancangan yang digunakan adalah rancangan acak kelompok dengan enam perlakuan dan tiga ulangan. Hasil uji statistik, menunjukkan bahwa pemberian pupuk organik, tidak memberikan pengaruh yang nyata terhadap jumlah karbon organik dan nitrogen total tanah, antara sebelum penanaman dan sesudah masa panen.
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Judul: Perubahan sifat kimia tanah andisol Cisarua akibat pemberian berbagai jenis pupuk organik yang diperkaya bahan mineral
Abstrak: Pertanian organik adalah suatu sistem pertanian yang meminimumkan input luar dan menghindarkan penggunaan pupuk sintetik, sehingga dihasilkan produk pertanian yang sehat. Sebagai sumber utama input hara dalam sistem ini adalah pupuk organik. Telah dilakukan penelitian tentang pengaruh berbagai pupuk organik yang diperkaya bahan mineral terhadap perubahan sifat kimia tanah. Parameter yang dianalisis adalah C organik, N total, P dan K cadangan, kation dapat ditukar (K-dd, Ca-dd, Mg-dd), kapasitas tukar kation (KTK), dan kejenuhan basa (KB). Rancangan yang digunakan adalah rancangan acak lengkap dengan tiga kali ulangan dan sembilan perlakuan pupuk organik yang diperkaya bahan mineral berbagai kombinasi. Kandungan C organik, N total, P cadangan, dan KTK diukur menggunakan spektrofotometer UV-vis, sedangkan kandungan K cadangan, K-dd, Ca-dd, dan Mg-dd diukur menggunakan spektrofotometer serapan atom. Hasil penelitian menunjukkan pemberian berbagai pupuk organik berpengaruh secara nyata terhadap kadar N-total, P dan K cadangan, Ca-dd, Mg-dd, dan KB pada contoh tanah sebelum tanam. Pada pengamatan tanah setelah panen, parameter yang berbeda nyata adalah P cadangan dan Ca-dd. Kadar K cadangan, N total, K-dd, Cadd, KTK, dan KB pada tanah setelah panen meningkat dibanding pada tanah sebelum tanam; sedangkan C organik , nisbah C/N, dan P cadangan kadarnya pada tanah setelah panen menurun dibanding pada tanah sebelum tanam. Perlakuan 8 (pukan kambing + kompos Thitonia + fosfat alam + dolomit) menghasilkan buah tomat paling banyak, yaitu 175.6 g/pot.
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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