Allometry of the box crab Calappa convexa De Saussure, 1853 (Brachyura, Calappidae) in the southeastern Gulf of California

The relative growth of Calappa convexa can be used to identify dimorphism or morphological change related to sexual maturation. The carapace width (CW) against width and length of the propodus of the right and left cheliped were tested to obtain a coefficient of allometry. CW against total wet weight WT values were analysed for length-weight relationships (LWR). Relative growth was analysed by a multi-model approach. Five models were tested and the best was selected due to the greater weight of the Akaike criterion (). Significant differences between sexes were found in CW (, ) and WT (, ). The negative or positive allometry varied according to the morphometric relationship and sex. No real winner model () was observed in the LWR analysis under a multi-model approach. The average model estimated a breakpoint at 118 mm CW in males and 132 mm CW in females.

DINAMIKA MUSIM PENANGKAPAN IKAN CAKALANG DAN TONGKOL DI PERAIRAN PALABUHANRATU

The monthly fluctuation of fish catch is closely related to the presence of fish or the fishing season. Information about the fishing season is important to improve the efficiency and effectiveness of fishing carried out by fishermen. Skipjack and tuna are important catches landed by fishermen in Palabuhanratu fishing port, with fishing grounds in the waters around Palabuhanratu Bay. This study aims to describe the dynamics of the catch and the effort to catch skipjack and tuna that land their fish in the Palabuhanratu fishing port and determine the fishing season. The data used is the Palabuhanratu fishing port fisheries statistical data for the 2015-2019 period. Data analysis used catch per unit effort (CPUE) analysis and moving average model. The results showed that the CPUE value of skipjack tuna fluctuates tends to increase by 0,009 tons per trip and reaches the highest in 2017 which is around 3,068 tons per trip. The CPUE value of tuna tends to increase from 0,021 tons per trip in 2015 to 0,266 tons per trip in 2019. The skipjack tuna fishing season occurs in March, July to November, while the tuna fishing season occurs from July to November. Keywords: skipjack tuna, fishing season index, moving average model, tongkol, Palabuhanratu

An Average Model of DC–DC Step-Up Converter Considering Switching Losses and Parasitic Elements

Power electronic converters represent a pillar of modern power systems, especially since generation from renewable energy sources, such as photovoltaics, have been introduced. One of their main characteristics consists of the high flexibility in converting different voltage levels and waveforms. As for all the conversion devices, they are subjected to unavoidable losses introduced by non-ideal components. For this reason, in the last few decades numerous research activities have been devoted to model their behavior and predicting the global efficiency. In spite of the number of scientific publications on the topic, the non-idealities have been rarely studied in terms of their impact on the input-output characteristics of the converter. In this paper, the conventional equivalent circuit of a step-up DC/DC converter has been upgraded in order to introduce the effects of both conduction and switching losses. The obtained formulation, applicable to all DC/DC converters, allows a more accurate average model that is particularly suitable for the study of multi-converter architectures, as for the most recent renewable energy sources applications. Finally, thanks to a dedicated test setup, the results of an experimental campaign demonstrate how the new formulation faithfully predicts its electrical behavior.

Research on Synchronization Mechanism of Artificial Intelli-gence Model Based on Belief Measure and Its Application in Pumped Storage Power Station

For the security monitoring of pumped storage power station, a model synchroniza-tion mechanism for cloud edge cooperation framework is proposed. The method uses the belief function to describe the threshold and uses the ping-pong operation strategy to update the model alternately, which solves the problem of artificial intelligence model synchronization and update of edge equipment. The cloud is based on Baidu BML platform, the edge uses customized servers, and the average model update cycle is about three months.