Judul: Efisiensi air pada budidaya tanaman tebu Saccharum officinarum : Analisis kebutuhan air irigasi dan masa tanam optimal di areal PG Rejosari PTP XI Magetan Jawa Timu
Abstrak: Tanaman Tebu (Saccharum officinarum) memiliki karakteristik yang khas, pada umur 1-9 bulan dibutuhkan jumlah air yang banyak sedangkan pada umur 10-12 bulan menghendaki keadaan yang kering atau sedikit air. Areal PG Rejosari memiliki sumber daya air yang sangat terbatas, hal ini diperburuk lagi dengan adanya persaingan pemanfaatan air irigasi dengan tanaman lain khususnya tanaman padi sehingga diperlukan adanya pengelolaan air pengairan yang tepat dan penyesuaian masa tanam guna mengefisienkan sumber daya air yang ada dan meningkatkan produktifitas tanaman tebu. Tujuan penelitian ini untuk mengetahui jumlah kebutuhan air irigasi pada masa tanam optimal dan mengetahui pengaruh karakteristik lahan dalam menahan dan menyimpan air irigasi di Areal PG Rejosari. Penelitian ini dilakukan di PG Rejosari. Analisis sifat fisik tanah dilakukan di Laboratorium Fisika dan Konservasi Tanah; Laboratorium Genesis, Klasifikasi dam Mineralogi Tanah. Penelitian berlangsung mulai bulan Mei hingga bulan Juli 2004. ...
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Judul: Analisis Neraca Air Menggunakan Model Simulasi pada Tanaman Tebu (Studi Kasus: Kabupaten Kediri, Jawa Timur).
Abstrak: Produktivitas tebu diantaranya dipengaruhi faktor iklim dan dibatasi oleh ketersediaan air. Penelitian ini menyimulasikan model neraca air tanaman tebu untuk menduga nilai kebutuhan air dan waktu tanam terbaik berdasarkan produktivitas optimumnya di Kabupaten Kediri. Pendugaan kebutuhan air tanaman didasarkan pada kehilangan air akibat evapotranspirasi dan pengaruh fase pertumbuhan, sedangkan nilai produktivitas tebu dihitung berdasarkan pertumbuhan dan perkembangan tanaman tebu tipe masakan tengah. Estimasi kebutuhan air tanaman tebu berkisar antara 26-128 mm/bulan dengan 77% air digunakan saat fase vegetatif untuk pertunasan dan pemanjangan batang (3-9 bulan setelah tanam). Keragaman produktivitas tebu paling tinggi diperoleh pada bulan tanam Juli-September berdasarkan hasil simulasi. Kekurangan air ditemukan terjadi lebih besar pada penanaman bulan November-April dibandingkan penanaman pada bulan Juli-September, terutama di lahan kering. Selain itu, pemberian air irigasi harian pada kondisi kekurangan air dapat meningkatkan hasil tebu hingga 30 kg/ha/mm. Defisit air pada masa pertengahan pertumbuhan tebu dapat menurunkan produktivitas tebu dalam jumlah yang cukup besar dibandingkan dengan produktivitas tebu yang tidak terkena defisit air. Hasil kajian dalam penelitian ini dapat digunakan untuk membantu pengambil keputusan dalam manajemen irigasi dan penentuan waktu tanam terbaik.
Keyword: neraca air, pemodelan tanaman, produktivitas tebu

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