Judul: Parameter Oseanografi Kaitannya dengan Produksi Hasil Tangkapan Ikan Pelagis Besar di Perairan Teluk Palabuhanratu
Abstrak: The availability of big pelagic species in waters of Palabuhanratu Bay always changes all the time. It causes the number of fish catches by payang vessel to fluctuate significantly. One of suspected causes was correlation to oceanographic influences such as Sea Surface Temperature (SST) and chlorophyll-a. The purposes of this research were to estimate the productivity and peak season of big pelagic species; identify the SST and chlorophyll-a variability on waters of Palabuhanratu’s Bay, and analyze correlation between oceanographic parameter with the number of fish catches. This research used comparative analysis and case study. The result showed that the productivity of cakalang and tongkol decrease every year; peak season of tongkol occured on June, September, Oktober, November and December whereas cakalang occured on January, April, May, June and July; the value and coeficient of SST variability were 2,39 and 5,37; the value and coeficient of chlorophyl-a variability were 0,68 and 49,53; the correlation between oceanographic parameter and tongkol catch was very low while the correlation between oceanographic parameter and skipjack tuna cacth was low.
Keyword: chlorophyll-a., SST, skipjack tuna, tongkol, payang

Judul: Catching productivity and biotechnical economic analysis of Danish Seine Net Fishing Units at Palabuhanratu Fishing Port
Abstrak: Volume produksi ikan tongkol di PPN Palabuhanratu tahun 2017 sampai 2021 menunjukkan trend menurun. Salah satu alat tangkap yang menangkap tongkol adalah payang. Penelitian ini bertujuan menganalisis produktivitas penangkapan dan bioteknik ekonomi unit penangkapan payang di PPN Palabuhanratu. Analisis yang dilakukan yaitu CPUE, komposisi hasil tangkapan, korelasi Pearson, dan analisis ekonomi. Penelitian dilakukan di PPN Palabuhanratu, pada bulan April sampai Mei 2022, menggunakan metode observasi dan wawancara. Produktivitas unit penangkapan payang mengalami fluktuasi dan pada tahun 2021 terjadi penurunan sebesar 50% tetapi trend yang dihasilkan masih stabil. komposisi hasil tangkapan payang di antaranya cakalang, eteman, peperek, tongkol lisong, tongkol banjar, dan tongkol abu-abu. Terdapat beberapa jenis ikan dengan volume produksi yang rendah tetapi bernilai ekonomis di antaranya ikan selar bentong, kuwe, dan gulamah. Faktor teknis yang mempengaruhi produksi kegiatan penangkapan adalah lama setting dan hauling, jumlah ABK mempengaruhi waktu yang dibutuhkan untuk melakukan setting dan hauling. Analisis ekonomi dari kelayakan usaha diperoleh keuntungan sebesar Rp79.928.095,00, PP selama tiga tahun delapan bulan, dan ROI sebesar 20,88%, kelayakan investasi menunjukkan nilai NPV sebesar Rp230.766.053,00, nilai IRR sebesar 24,1%, dan nilai Net B/C 1,786 sehingga usaha menguntungkan dan investasi layak dilakukan., The volume of mackerel tuna production at Palabuhanratu Fishing Port in 2017 to 2021 shows declining trend. One fishing gear that catches mackerel tuna is danish seine net. This study aims to analyze catching productivity and biotechnical economic of danish seine net fishing unit at Palabuhanratu. Analysis carried out is CPUE, catch composition, Pearson correlation, and economic analysis. The research was conducted at Palabuhanratu Fishing Port, in April to May 2022, using observation and interview methods. The productivity of danish seine net fluctuates, in 2021 there will be a 50% decrease in productivity, but resulting trend is still stable. The composition of danish seine net catch included skipjack tuna, moonfish, ponyfish, bullet tuna, black skipjack, and longtail tuna. Fish with low production but high economic value include bigeye scad, giant trevally, and leaftail croaker. Technical factors that affect the production of fishing activities are the length of setting and hauling, number of crews affects time needed to setting and hauling. Economic analysis of business feasibility obtained profit Rp79.928.095.00, PP for three years and eight months, and ROI 20,88%, investment feasibility shows NPV value Rp230.766053.00, IRR value 24,1%, and Net B/C value is 1,786, so that business is profitable and investment is feasible.
Keyword: biotechnical economic analysis, catching productivity, danish seine net, mackerel tuna

Judul: Grup dan Homomorfisma Grup pada Rubik Revenge
Abstrak: Rubik cube is a kind of puzzle game. A player must arrange rubik sides, which have been disordered, back to the position where every side has the same colour. This paper does not focus on the settlement solution, but instead on proving the existence of a group homomorphism between rubik movement group and S96 symmetric permutation group in rubik revenge. Firstly, it has been proved that rubik movement set is a group. Then, it also has been proved that the M set, which contains numeric labels of 1 until 96 in cubinos sides, is S96 symmetric permutation group.
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