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: Kelulusan hidup rekrutmen karang (Scleractinia) di perairan gugus Pulau Pari, Kepulauan Seribu, Jakarta
Abstrak: One of all important phase is the development of coral recruitment and survival after settlement of the allegedly affected by the internal condition of coral recruit and external from environment. Research survival of coral recruits have been conducted in Pari Islands, Kepulauan Seribu, Jakarta, from March to November 2010 with the purpose to know the level of survival of coral recruits on the life form and size of different colonies. In this study selected two life forms Massive and Branching colonies at number 15 colonies in the area belt transect 2 meters x 70 meters at 5-7 meters depth. Furthermore, on each life form, coral recruit again grouped into 3 classes, Small (<3 cm), Medium (3-6 cm), and Large (> 6 cm and 10 cm ≤). Observations were made at two stations namely ST1-pari and ST2-tikus with observe one month interval (March-August) and three months interval (September-November). At the same time measurement of water quality and biological factor such as competitor, predator and desease. Coral recruits in the study site is multiple diverse with species richness reach to 15 genera from 10 families consist of 9 genera at ST1-pari and 8 genera at ST2-tikus which genera of Faviidae most dominated, in fact recruits Faviidae rare and even absent in the stages of larva settlement. Density of coral recruits is high diversity index and tended to stabilize. The observation result shows that the difference between Massive survival rate higher than Branching. Survival of Medium size was lowest compared two other size indicated that this class is vulnerable period for survival of coral recruits. Water conditions Northern of Pari Island or the Station ST2-tikus are more supportive to the development and survival of coral recruitment compared Southern or ST1-pari. The quality of waters within the normal range, while the sedimentation and nutrient content of waters predictable impact on the survival of coral recruits.
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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.
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