Judul: Vertical Distribution Of Temperature And Dissolved Oxygen Related To Floating Cage Activitiy In Cirata Reservoir, West Java
Abstrak: Cirata Reservoir was built for hydropower to supply electricity for Java and Bali Islands. It is also used for fish culture in floating cage. However, aquaculture in Cirata Reservoir has been far exceeded carriying capacity. This research aims to analyze the vertical dissolved oxygen (DO) profile, determining the factors causing the hypoxia, and qualitatively explaining the response of hypoxia related to floating cage activity. Investigation and water sampling were conducted at four sites with and without floating cage activity. Data on DO, temperature, pH and chemical oxygen demand (COD) were collected weekly for six weeks from April to May 2015. The DO concentration in intensive cage area was lower than in no cage area. DO concentration in areas with intensive cage fell to hypoxia (< 3 mg/l) at 7 m of depth in the first week and moved upward to 4 m of depth in sixth week observation. COD and pH in intensive cage areas were significantly different (P<0.05) from the area with no cage activitiy. The hypoxic and anoxic layers could be dangerous if it continues to be supported by the long rainy days because it may be followed by the upwelling events and the massive fish kills. Nitrate, nitrite and ammonium in intensive cage area have no significantly diffenrent concentration from no cage area. But generally, these parameters have higher concentration in intensive cage area. The highest nitrite concentration found in water column at 20 m (0.003 mg/l). Orthophosphate and chlorophyll-a concentration in intensive cage area is significantly higher than no cage area. Vertically, orthophosphate and chlorophyll-a also have significantly different concentration. From dendrogram graph it is showed that floating cage activities affect to the different characteristic of N, P and chlorophyll-a in Cirata Reservoir.
Keyword: chlorophyll-a, Cirata Reservoir, floating cage, hypoxia, oxygen stratification

Judul: Keterkaitan Kegiatan Keramba Jaring Apung (KJA) Dengan Tingkat Kesuburan di Waduk Cirata, Jawa Barat
Abstrak: Trophic states monitoring in Cirata Reservoir is an important thing in sustainable management for hydropower plan and floating net cage. The purpose of this research is to analyze trophic states of Cirata Reservoir based on physical, chemical, and biological parameters using some index related to existence of floating net cage in Cirata Reservoir. Trophic states were calculated by some index which is index Nygaard (In), Trophic State Index (TSI), Trophic Index (TRIX), Trophic Level Index (TLI), and Delphi Method (R[DM]). Cluster analysis and principal component analysis indicated that the station group consist of Station KJA that influenced by dissolved oxygen, temperature, Secchi disk depth, and chlorophyll-a, and Station inlet of Citarum River that influenced by total dissolved solid and total phosphate. The results show that the values of In, TSI, TRIX, TLI and R[DM] of Station KJA and inlet of Citarum River are indicated as hypereutrofic. All of the indexs are still relevant to describe the trophic states of Cirata Reservoir.
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Judul: Konstruksi aritmetika kurva eliptik F(2m) supersingular dan non-supersingular untuk skema kunci publik ElGamal
Abstrak: Algoritme ElGamal adalah salah satu algoritme kunci publik dengan aritmetik modular p yang mempunyai struktur grip siklik Z(p). Tingkat keanaman algoritme ini terletak pada pemecahan masalah logaritme diskret dari Z(p). Akan tetapi, tingkat keamanan tadi tahun ke tahun semakin menurun yang disebabkan kemampuan pemecahan algoritme diskret semakin meningkat. Untuk memenuhi tingkat keamanan yang memadai dibutuhkan p yang cukup besar yang menyebabkan proses enkripsi dan dekripsi menjadi lambat.
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