• Animal cells and systems
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• v.14 no.4
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• pp.291-296
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• 2010

Population ecological characteristics of growth and mortality play an important role in understanding the population dynamics of marine mammals. The instantaneous coefficients of natural and bycatch mortality were estimated for minke whales (Balaenoptera acutorostrata) in Korean waters using a population assessment model composed of bycatch and abundance data. The survivorship curve of this population was fitted to the data, and then the curve was revised using age-specific relative bycatchability coefficients ($q_t$). Instantaneous coefficients of natural and bycatch mortality of minke whales were estimated as 0.024/year and 0.076/year, respectively, and from this the survival rate was estimated as 0.905. This estimated survival rate was comparable to other cetaceans in other regions. The $q_t$ for this population ranged from 0.020 to 0.193. The revised survival rates were higher when the $q_t$ was taken into account. The mortality coefficient, survival rate, $q_t$ and survivorship curves had not previously been determined for minke whale in this area. This estimate could serve as fundamental information to assess the status of this population and for conservation and rational management.

• Structural Engineering and Mechanics
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• v.75 no.4
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• pp.445-454
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• 2020

Structural damage identification (SDI) is a crucial step in structural health monitoring. However, some of the existing SDI methods cannot provide enough identification accuracy and efficiency in practice. A novel whale optimization algorithm (WOA) based method is proposed for SDI by weighting modal data and flexibility assurance criterion in this study. At first, the SDI problem is mathematically converted into a constrained optimization problem. Unlike traditional objective function defined using frequencies and mode shapes, a new objective function on the SDI problem is formulated by weighting both modal data and flexibility assurance criterion. Then, the WOA method, due to its good performance of fast convergence and global searching ability, is adopted to provide an accurate solution to the SDI problem, different predator mechanisms are formulated and their probability thresholds are selected. Finally, the performance of the proposed method is assessed by numerical simulations on a simply-supported beam and a 31-bar truss structures. For the given multiple structural damage conditions under environmental noises, the WOA-based SDI method can effectively locate structural damages and accurately estimate severities of damages. Compared with other optimization methods, such as particle swarm optimization and dragonfly algorithm, the proposed WOA-based method outperforms in accuracy and efficiency, which can provide a more effective and potential tool for the SDI problem.

• The Korean Journal of Quaternary Research
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• v.18 no.2 s.23
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• pp.87-92
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• 2004

The rock engraving of the Korea are dated by a very few direct archaeological contexts by linking their images to objects of known prehistoric date-although many of the figures are 'abstract'. This paper focuses on the rock art of Bangu-dae, located in the south-east of Korea. I try to the date of engravings from their contexts and the ways in which they can be studied.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.799-802
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• 1995

Whale helical gears is used to transmit motion between parallel shafts, the shaft bearings are subjected to both radial and thrust loads. The reliability and life analysis are based on the two-parameter Weibull disribution lives of the component gears and bearings. Two methods of estimating the time between gear system overhauls and the number of replacement components needed were presented. The first method assumes replacement of all components during an overhaul of a failed gear system. the second method assumes replacement of failed comonents only. Renewal theory was presented to estimate the number of comonent replacements in a gear system for both methods.

• Nuclear Engineering and Technology
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• v.54 no.6
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• pp.2107-2119
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• 2022

Accurate remaining useful life (RUL) prediction for critical components of nuclear power equipment is an important way to realize aging management of nuclear power equipment. The electric gate valve is one of the most safety-critical and widely distributed mechanical equipment in nuclear power installations. However, the electric gate valve's extended service in nuclear installations causes aging and degradation induced by crack propagation and leakages. Hence, it is necessary to develop a robust RUL prediction method to evaluate its operating state. Although the particle filter(PF) algorithm and its variants can deal with this nonlinear problem effectively, they suffer from severe particle degeneracy and depletion, which leads to its sub-optimal performance. In this study, we combined the whale algorithm with regularized particle filtering(RPF) to rationalize the particle distribution before resampling, so as to solve the problem of particle degradation, and for valve RUL prediction. The valve's crack propagation is studied using the RPF approach, which takes the Paris Law as a condition function. The crack growth is observed and updated using the root-mean-square (RMS) signal collected from the acoustic emission sensor. At the same time, the proposed method is compared with other optimization algorithms, such as particle swarm optimization algorithm, and verified by the realistic valve aging experimental data. The conclusion shows that the proposed method can effectively predict and analyze the typical valve degradation patterns.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.50 no.6
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• pp.799-805
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• 2017

The whistle sounds of three Beluga whales Delphinapterus leucas were recorded four times, for an hour each time, in 2016 and analyzed to obtain the most stable and basic acoustic characteristics of the whales in captivity. This study investigated the whistle characteristics of beluga whales and the relationship between whistle sounds and behavior to understand the meaning of the whistle sounds. The whistles were classified into six types (flat, ascending, descending, hump, dip, and wavy type) by their frequency contour and shape. The most common type was the ascending type, accounting for>30% of total whistles. The fundamental frequency of whistles was 2.0-8.6 kHz. Four types of behavior were related with the sounds of beluga whales (aggressive, submissive, affiliative, sexual behavior). A flat whistle was the most recorded in the group and an aggressive act was observed in association with the flat whistle. A dip whistle were recorded more when submissive acts were observed.

• Journal of Advanced Navigation Technology
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• v.24 no.4
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• pp.291-298
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• 2020

This study proposed a model that can track MPP faster than the existing MPPT algorithm using the particle swarm optimization algorithm (PSO). The proposed model highly sets the acceleration constants of gbest and pbest in the PSO algorithm to quickly track the MPP point and eliminates the power instability problem. In addition, this algorithm was re-executed by detecting the change in power of the solar panel according to the rapid change in solar radiation. As a result of the experiment, MPP time was 0.03 seconds and power was 131.65 for 691.5 W/m2, and MPP was tracked at higher power and speed than the existing P&O and INC algorithms. The proposed model can be applied when a change in the amount of power is detected by partial shading in a Photovoltaic power plant with Photovoltaic connected in parallel. In order to improve the MPPT algorithm, this study needs a comparative study on optimization algorithms such as moth flame optimization (MFO) and whale optimization algorithm (WOA).

• Journal of the Korean Society of Food Culture
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• v.21 no.5
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• pp.446-455
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• 2006

This study was performed by questionnaire to investigate the dietary attitude and preference of native local foods for Ulsan citizens. The subjects were consisted of 500 citizens living in Ulsan area. The results of the survey are summarized as follows: On frequency of eating of local foods, 'one time per year' scored high as 40.8%. 'Labor-intensive' scored high as 35.6% in cooking methods. 'Rarely' scored high as 43.2% in frequency of cooking at home. A criteria of selection of Ulsan local foods was 57.2% in taste. The recognition score of native local foods was 'healthful food' (3.96 points), 'should be handed down to next generation' (3.94 points), and 'a lot of natural food ingredients' (3.88 points) and 'nutritious food' (3.87 points) in the order. The preferred native local foods of Ulsan area was 'Ulsa pear' (3.97 points), 'Eonyang, Bonggye Hanoobulgogi' (3.86 pionts), 'Raw Fish', 'Haemuljeongol', ‘Gangodeungojjim', 'Suknamsa SanchaeBibimbab' 'Gangdon Natural Brown Seaweed' in that other. On the other hand, the preference for 'Myeoljang', 'Whale Meat', 'Oksamju', 'Meonggejeon', 'Jepyipjangajji' and 'Kimchigam' was very low. Males liked 'Whale Meat', 'Raw Fish', Oksamju' and 'Dombaegi(Shark Meat)', while females liked 'Gandong Naural Brown Seaweed'. The most effectual food for developing tourism merchandising of Ulsan local foods was 'Eonyang, Bonggye hanoobulgogi' and the next is 'Eonyang Dropwort', 'Gangdong Natural Brown Seaweed', 'Myeoljang', 'Ulsan Pear', and 'Oksamju' in the order.

• Ocean and Polar Research
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• v.33 no.1
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• pp.35-43
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• 2011

Blubber plays different biological roles in cetaceans, including structural support, physiological demands (thermoregulation, streamlining, buoyancy, etc.), and energy storage. As such, biochemical composition, especially lipid, in the blubber may be vertically stratified in order to effectively assist with these functions. We analysed lipid content, class and fatty acid composition in the blubber of by-catch minke whale (Balaenoptera acutorostrata; n = 11), long-beaked common dolphin (Delphinus capensis; n = 3) and Pacific white-sided dolphin (Lagenorhynchus obiquidens; n = 2) from Korean waters. Lipid content for all three species ranged from 55 to 96% of wet weight, with a dominance of triacylglycerols. Vertical stratification of blubber lipid content was different between species. For minke whale and longbeaked common dolphin, it increased from inner (near the muscle) to outer (near the skin) layer, whereas it decreased for Pacific white-sided dolphin. Thirty-one fatty acids were found in all blubber samples and vertical stratification of fatty acid composition was similar among all three species. Among grouped fatty acids, monounsaturates were the most abundant, gradually increasing from inner to outer blubber layer, whereas polyunsaturates and saturates decreased. Such vertical stratification of lipid content and composition suggests that the modification and accumulation of lipid occur in the blubber itself in order to help cetaceans with their specific physiological needs.

• Journal of Fisheries and Marine Sciences Education
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• v.5 no.1
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• pp.15-22
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• 1993

The Maritime Traffic Safety Law of P. R. China has not the legal nature of navigation rule which regulates the vessel traffic directly but has the legal nature of management to ensure the safety and good order of the whale marine traffic. For that reason, the legal status of this Law is a general basic norm for the marine safety regulations rather than a definite enforcement regulation. This Law does not have any clear statements on adaptation of the steering and sailing rules of the International Regulations for Preventing Collisions at Sea, but it can be presumed the Convention would be applied on the viewpoint of the international practice. The subject matter of this Law is easily understandable, because the IMO and shipping countries have already made similar legislation. Since the maritime traffic condition of the P. R. China also has a direct effect upon the Korean coastal waters, it is essential to observe closely the process of enforcement and development of the P. R. China's Maritime Traffic Safety Law.