Judul: Stabilitas Agregat dan Permeabilitas pada Podsolik dan Regosol Akibat Aplikasi Bahan Organik Bambu Cacah
Abstrak: Penurunan produktivitas pertanian di Indonesia umumnya disebabkan oleh terjadinya penurunan kualitas tanah akibat penggunaan tanah secara terus-menerus. Penurunan ini diakibatkan oleh penggunaan lahan secara terus menerus dan penanganan yang belum efektif dalam jangka panjang, khususnya terkait dengan sifat fisik tanah. Sifat fisik seperti permeabilitas, bobot isi, ruang pori, dan stabilitas agregat mengalami penurunan kualitas akibat pengolahan lahan secara intensif. Hal tersebut dipicu oleh terjadinya penurunan kadar bahan organik tanah. Penelitian bertujuan mengkaji pengaruh aplikasi bahan organik berupa bambu cacah terhadap sifat fisik tanah (stabilitas agregat dan permeabilitas) pada Podsolik dan Regosol. Penelitian dilakukan pada skala rumah kaca menggunakan rancangan acak lengkap dengan dua faktor perlakuan, yaitu jenis tanah (Podsolik Lampung dan Regosol Dramaga) dan dosis bahan organik bambu cacah (0, 20, 40, 60 dan 80 ton ha-1 ). Parameter yang diamati yaitu bobot isi, porositas, permeabilitas dan stabilitas agregat. Hasil percobaan menunjukkan bahwa bahan organik bambu cacah menunjukkan indikasi tahan terhadap dekomposisi dan peningkatan dosis yang diberikan berpengaruh positif terhadap stabilitas agregat dan permeabilitas tanah. Permeabilitas Podsolik mengalami peningkatan dengan semakin meningkatnya dosis aplikasi bambu cacah. Stabilitas agregat Podsolik dan Regosol juga mengalami peningkatan dengan semakin meningkatnya dosis aplikasi bambu cacah. Stabilitas agregat memiliki hubungan yang erat dengan permeabilitas tanah.
Keyword: lahan perkebunan, penurunan kualitas lahan, resistensi, sifat fisik

Judul: Ketahanan Penetrasi dan Kekuatan Geser Regosol dan Latosol di Bawah Tegakan Bambu
Abstrak: Bambu berperan penting dalam menekan erosi dan meningkatkan stabilitas tanah. Penelitian bertujuan mengkaji nilai ketahanan penetrasi dan kekuatan geser Regosol dan Latosol di bawah tegakan bambu pada jarak yang berbeda dari rumpun bambu. Lahan bambu yang diteliti berlokasi di Kebun Pendidikan Cikabayan, Institut Pertanian Bogor. Hasil penelitian menunjukkan bahwa nilai ketahanan penetrasi dan kekuatan geser pada Latosol lebih tinggi dibanding Regosol. Nilai ketahanan penetrasi dan kekuatan geser pada Regosol cenderung semakin besar seiring dengan semakin jauh dari rumpun bambu, sedangkan pada Latosol cenderung semakin besar seiring dengan jarak yang semakin dekat. Perakaran bambu membuat tanah menjadi porous sehingga memudahkan akar untuk menembus tanah. Selain itu, akar bambu dapat menyebabkan adanya penguatan tanah karena kuat tariknya yang tinggi sehingga meningkatkan nilai kekuatan geser tanah.
Keyword: bamboo roots, penetration resistance, shear strength, water content

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