Judul: Mempelajari Neraca Air Tanah Harian untuk Estimasi Besarnya ETc dan Kc Tanaman Teh di PTPN VII Perkebunan Gunung Mas Puncak, Jawa Barat
Abstrak: Didalam proses pertanian, air merupakan salah satu faktor terpenting. Kebutuhan air bagi tanaman sebagian besar dari air tanah yang diserap akar tanaman dan ditranspirasikan melalui daun (Suseno, 1974). Banyaknya air yang diperlukan tanaman tergantung antara lain pada jenis tanaman, fase pertumbuhan dan evapotranspirasi yang ada hubungannya dengan faktor lingkungan seperti iklim, kesuburan tanah dan kelembaban tanah (Richards dan Wedleich, 1952). Hubungan antara kandungan air tanah dan pertumbuhan tanaman antara lain dapat dikemukakan bahwa pertumbuhan tanaman dapat dipengaruhi oleh bertambahnya kekeringan setelah kapasitas lapang. Pada lapisan tanah atas kandungan air tanah akan berkurang karena evaporasi dan transpirasi yang sangat dipengaruhi oleh unsur-unsur klimatologi, jenis tanah dan kedalaman tanah.
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Judul: Mempelajari kantong air (reservoir) untuk tujuan irigasi di Perkebunan Gedeh
Abstrak: Air merupakan salah satu unsur hara yang penting bagi tanaman. Kebutuhan air berbeda-beda untuk setiap tanaman, waktu dan tempat. Tanaman teh memerlukan syarat tumbuh dan air yang relatif tinggi dibandingkan tanaman keras lainnya sehingga biasanya tanaman teh ditanam pada daerah pegunungan. Pada beberapa perkebunan teh, ketersediaan air pada setiap waktu berfluktuasi banyaknya, sehingga hal ini menjadi salah satu faktor yang menjadikan rendah dan berfluktuasinya produksi teh. Penelitian ini bertujuan untuk mempelajari sistem irigasi, dan kelayakan pembuatan kantong air (reservoir), yang meliputi penentuan alat, jadwal, dan jumlah air irigasi, serta volume & tempat yang ideal dari kantong air (reservoir) di perkebunan teh. Kantong air (reservoir) diharapkan dapat menyuplai air untuk kebutuhan tanaman dan pemeliharaan tanaman serta menyimpan kelebihan air. Penelitian ini juga bertujuan untuk menyarankan beberapa alternatif irigasi yang sesuai dengan perkebunan teh, berdasarkan ketersediaan air yang sesungguhnya. Penelitian dilakukan di Perkebunan Gedeh, Cugenang, Cianjur, Jawa Barat. Penelitian dimulai dengan pengukuran topografi, pengukuran sifat fisik tanah, seperti infiltasi, dan tekstur tanah. Pengambilan data sifat-sifat tanaman teh dan data analisis kelayakan dilakukan dengan studi pustaka dan survey lapangan untuk mendapatkan hasil yang aktual. ...
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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