Judul: Analisis Neraca Air DAS Mentaya Kabupaten Kotawaringin Timur dan Pengaruh ENSO Terhadap Ketesediaan Air Wilayah
Abstrak: Mentaya watershed is a catchment area in Kotawaringin Timur regency, Central Kalimantan Province as a source of water supply and transport pathways. DuringEl Nino Southern Oscilliation (ENSO) years rainfall will changeand affect the availabilityof water in the watershed. The purpose of this study is to estimate the amount of water available in Mentaya watershed at normal and ENSO years through landwater balance model. Method to analyze water balance components isMockwater accountingmethod that was modified for soil moisture (SM) and actual evapotranspiration (ETa). The study area is upstream part of Mentaya watershed with total area 5459.2 km2that has red-yellow podzolic soil with a sandy loam texture and forest cover. Annual rainfalls of El Nino (1997), Normal (2006) and La Nina (2000) years were1664.5 mm, 2941.2 mm and 3494.4 mm, respectively. Evapotranspirated water (ETa) in El Nino, La Nina, and normal years were 67%, 53% and 54 % of the annual rainfalls, respectively. Total runoff ( RO ) in the year of El Nino, La Nina, and the normal rate of 35%, 50%, and 47% of the annual rainfall. Precipitation, RO water balance and measurement were lower in El Nino (1997) year and higher in La Nina (2000) year than in normal year (2006)
Keyword: Mock method, soil moisture, runoff, actual evapotranspiration, precipitation

Judul: Karakteristik Kekeringan Hidrologi di Wilayah Kalimantan Bagian Timur
Abstrak: This study aimed to identify the hydrological drought using groundwater recharge component and analyze the relation between hydrological drought and ENSO phenomena. Water balance model with monthly rainfall and ETp input was used to assess the monthly recharge value from 1901 to 2009. In this study we used a monthly varying threshold method. The threshold varied depending on the climate regime and soil condition. Drought in groundwater was considered when the monthly recharge is below the drought threshold. We found that the longer drought duration, the volume deficit would significantly increase. Additionally, the longer drought duration, the number of drought events would significantly reduce. This study indicates that Samarinda region under peat soil and forest cover is more prone to drought as indicated by the highest drought frequency (56). In other hand, Banjarmasin region under mineral and forest cover is less vulnerable to drought. Furthermore, this study shows that peat soils are more pronounced to severe drought than mineral soils. Our findings also confirmed that strong El-Niňo would trigger severe hydrological droughts.
Keyword: Bogor Agricultural University (IPB), ENSO, duration, threshold, volume deficit, recharge

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