Judul: Size spectra of plankton biomass and its potential utilization for fish community at limnetic zone of the Ir. H. Djuanda Reservoir, West Java
Abstrak: The total area of Djuanda reservoir (8,300 ha) in West Java compose of 56-86% of limnetic zone and the rest of littoral zone. The limnetic zone of the reservoir mostly rich in plankton but rare in fish inhabiting this area. Eutrophication process of the reservoir is very intensiv e due to intensive activity of fish cage culture. Objectives of the research are to analyze and describe (1) plankton community structure and biomass; (2) fish community structure and biomass; (3) trophic efficiency of the food web in relation to the niche ecology; and (4) to analyze the research results of point 1, 2 and 3 in optimizing the utilization and management of the resources. The data were analyzed descriptively and statistically including of analyzing: (1) impact of N and P loading on the growth of phytoplankton; (2) the zooplankton grazing and filtration on the growth of the phytoplankton; (3) the flow efficiency of energy on the food web, and (4) the implication of ecosystem dynamics of the limnetic zone in relation to management option for fisheries development.
Keyword: Ekosistem pelagis, Pebgelolaan perikanan Waduk Djuanda, Grazing Zooplankton, Fitoplankton, Perikanan tangkap

Judul: Estimation of Natural Fishery Production Based on  Phytoplankton Carbon Content in Jatigede Reservoir, Sumedang, West Java.
Abstrak: Fitoplankton merupakan organisme autotrof yang dapat memanfaatkan energi karbon dari CO2 dengan bantuan sinar matahari melalui proses fotosintesis. Tujuan penelitian ini untuk menduga potensi perikanan alami melalui kandungan karbon biovolume sel fitoplankton dan kandungan klorofil-a di Waduk Jatigede. Pengambilan contoh dilakukan pada bulan Februari, Maret, dan April 2021 pada enam titik Stasiun. Pengukuran biovolume sel dilakukan menggunakan metode geometrik. Hasil penelitian menunjukkan kandungan karbon fitoplankton tertinggi terdapat di zona riverine. Uji statistik dilakukan untuk mengetahui perbedaan kandungan karbon fitoplankton di setiap zona. Hasil uji menunjukkan kandungan karbon fitoplankton di setiap zona relatif sama. Analisis potensi perikanan alami dilakukan berdasarkan nilai karbon biovolume sel fitoplankton dan kandungan klorofil-a. Potensi perikanan alami berdasarkan pendekatan karbon biovolume sel fitoplankton sebesar 6,66 ton/tahun, dengan nilai produktivitas primer sebesar 92,57 gC/m2 /tahun. Potensi perikanan alami berdasarkan kandungan klorofil-a sebesar 10,77 ton/tahun, dengan nilai produktivitas primer sebesar 413,35 gC/m2 /tahun., Phytoplankton is an autotrophic organism that can utilize carbon energy from CO2 with the help of sunlight through the process of photosynthesis. This study aimed to estimate the potential of natural fisheries through phytoplankton cell biovolume carbon content and chlorophyll-a content in Jatigede Reservoir. Sampling was conducted in February, March, and April 2021 at six stations. Cell biovolume measurements were made using the geometric method. The results showed that the highest phytoplankton carbon content was found in the riverine zone. Statistical tests were conducted to determine differences in phytoplankton carbon content in each zone. The test results showed that the carbon content of phytoplankton in each zone was relatively similar. Natural fisheries potential was analyzed based on phytoplankton cell biovolume carbon value and chlorophyll-a content. The potential of natural fisheries based on the phytoplankton cell biovolume carbon approach was 6.66 tons/year, with a primary productivity value of 92.57 gC/m2 /year. Natural fisheries potential based on chlorophyll-a content is 10.77 tons/year, with a primary productivity value of 413.35 gC/m2 /year.
Keyword: biovolume, carbon, natural fisheries, phytoplankton

Judul: Analisis dan Implementasi Certificate Authorities (CA) pada Public Switched Telephone Network (PSTN)
Abstrak: Secure Telephone Protocol has ability to authenticate involved party and keep the secrecy of the message sent over the protocol. The secrecy of the message archieved by using symmetric key cryptographic scheme, and authentication archieved using public key cryptographic scheme. One of several party involved in the protocol and hold an important function called Certificate Authorities or CA. CA responsible for generating public key pair for other party involved in the protocol. When CA generates public key pair, several primitive cryptographic scheme used for guarantee the security of the key. Two of them are hash function SHA-1 and El-Gamal public key scheme embedded in Digital Signature Algorithm scheme. The prototype implementing the scheme above developed using Java programming language with JCE addition from Bauncy Castle. The analysis towards implemented prototype indicates that the prototype still has some flaws to be implemented in real world.
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