Judul: Rekrutmen Karang pada Terumbu Buatan di Perairan Pulau Karya, Kepulauan Seribu
Abstrak: Artificial reefs have been submerged in the Karya Island’s reef area which are important for coral recovery. The coral recovery could be identify from coral recruits attached to the surface of artificial reefs. Each coral colony was photographed and identified to the highest taxa based on its coralite. The coral colony’s length and area was measured. Two different substrate materials of artificial reef were observed: nets and PVC. A total of 383 coral colony was recorded attach to the artifial reefs. The highest number of coral recruits was observed on the PVC substrat (347 colonies). Coral recruit on PVC substrate had average length of colonies is 18.5 cm, with montipora as the longest, simmiliar to the nets substrate has highest average of colony its 111,1 ± 124,6 cm2, with Pocillopora as the longest. The PVC substrate was observed as the highest area is 154,5 cm2, with Montipora as the largest area. The study found that suitable substrate for coral recruitment media is PVC with horizontal bottom position.
Keyword: artificial reef, coral reef, nets Substrate, PVC Substrate, Coral Colonies, Coral Recruitment

Judul: Struktur dan Pertumbuhan Karang Rekrutmen Pada Terumbu Buatan Modul Beton di Pulau Harapan, Kepulauan Seribu, DKI Jakarta
Abstrak: Coral reefs are a renewable resource that has the important function of Ecology, socio-economic, and culture. In Indonesia, the damage to the coral reef ecosystem is largely due to human activities. To speed up the recovery of coral reefs, several methods of rehabilisationare used such as transplantation and artificial reefs. The purpose of this study was (1) to know the growth rate of coral attached (recruitment) on concrete artificial reef modules, and (2) to determine the structure of coral communities on artificial reefs over a period of 1 year. In this study measured the growth of coral recruitment covering the length and width, survival rates, and recruitment of coral community structure. Types of coral recruitment was dominated by Pocillopora, Millepora and Acropora with a total of 59 species of 65 species of coral recruitment found. Growth in average length was highest in the range of months from January-May 2011 were 0.76±1.98 cm, and the width of the growth of the highest average in the range of months from May-July 2011 were 1.18±0.92 cm.
Keyword: reef community structure, coral recruitment, coral growth, artificial reefs

Judul: The Exploration of Discrete Logarithm over Finite Field GF(3m)
Abstrak: The security of many public~key algorithms is based on the problem of finding discrete logarithms. The generalized discrete logarithm problem is the following: given a finite cyclic group G of order n, a generator a of G, and an element fl E G, find the integer x, 0 ~ x ~ n - 1, such that 0: = fl. Algorithm for discrete logarithm problem focused on Menezes et al. (1997) that consist of exhaustive search algorithm, the baby-step giant-step algorithm, Pollard's rho algorithm, Pohlig-Hellman algorithm, and index-calculus algorithm. These algorithms are explorated to be used in discrete logarithm problem over finite field GF(3m ). The exploration also produces some algorithms, i.e. naif negative algorithm, baby-step mother-step algorithm, baby-step mother free-step algorithm, and baby-step free-step algorithm. All algorithms implemented using Maple 11. The Pohlig-Hellman and baby-step giant-step algorithms are efficient enough to be used in discrete logarithm problem over finite field GF(3m ) for m < 20.
Keyword: