Judul: Hubungan karakteristik lahan dan lingkungan dengan produksi teh di Jawa Barat
Abstrak: Penelitian ini bertujuan untuk mengetahui hubungan antara karekteristik lahan dan lingkungan dengan produksi teh. Untuk keperluan ini dilakukan pengamatan profil tanah, pengumpulan data iklim dan produksi teh di enam lokasi perkebunan yaitu Gunung Mas, Gedeh, Panyairan, Goalpara, Rancabali dan Panglejar pada PT. Perkebunan XII, Jawa Barat sejak Juni hingga Desember 1991. Metode pendekatan dalam melakukan penelitian adalah metode survei yang bersifat eksplorasi, yaitu variasi satuan lahan yang didasarkan pada blok-blok pertanaman teh yang dipilih. Dasar pemilihan dan penetapan lokasi adalah bahan tanaman teh yang sama. Dari hasil pengamatan di lapangan dan analisis laboratorium faktor-faktor yang sangat mempengaruhi dan saling berkaitan dalam pembentukan tanah adalah topografi, bahan induk dan iklim. Pada semua kebun terdapat topografi yang sangat bervariasi dari datar sampai berbukit dengan bahan induk tufa andesit, breksi andesit dan endapan kolavium. Menurut klasifikasi tanah, pada lokasi penelitian terdapat dua ordo tanah yaitu Inceptisol dan Ultisol.
Keyword: Beverage plants, Tea, Inceptisol, Ultisol

Judul: Sifat fisik, kimia dan biologi tanah serta produksi teh (Camellia sinensis (L) Kuntze) pada andisol di perkebunan teh gunung mas PTPN VIII, Cisarua, Bogor
Abstrak: Penelitian ini bertujuan untuk mengetahui sifat fisik, kimia dan biologi tanah pada posisi lereng bagian atas, tengah dan bawah serta untuk mengetahui hubungan antara sifat fisik, kimia dan biologi tanah dengan produksi teh Penelitian ini dilakukan di Perkebunan Teh Gunung Mas PTPN VIII, Cisarua, Bogor. Analisis sifat tanah meliputi: tekstur tanah, bobot isi, porositas, pH, Al-dd. P-tersedia, C-organik, N-total, nitrat, basa-basa dapat dipertukarkan, KTK, total mikroorganisme tanah, fungi tanah dan respirasi tanah. Hasil analisis sifat fisik tanah yang diperoleh menunjukkan bahwa bobot isi tanah tergolong rendah, porositas tergolong tinggi dan memiliki tekstur tanah yang didominasi oleh fraksi pasir. Data sifat fisik tanah keempat kebun menunjukkan bahwa tidak ada perbedaan antara nilai bobot isi dan porositas pada posisi lereng bagian atas, tengah dan bawah. Musim hujan umumnya memiliki nilai pH, P-tersedia, C-organik, C/N dan KTK lebih rendah dibandingkan musim kemarau, sedangkan nilai Al-dd, N-total dan basa- basa dapat dipertukarkan umumnya lebih tinggi pada musim kemarau dibandingkan musim hujan.
Keyword: Camellia sinensis (L) Kuntze, Tea plant, Andisols

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