• KSII Transactions on Internet and Information Systems (TIIS)
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• 제17권8호
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• pp.2278-2291
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• 2023

Imported ornamental fish should be quarantined because they can have dangerous diseases depending on their habitat. The quarantine requires a lot of time because quarantine officers collect various information on the imported ornamental fish. Inefficient quarantine processes reduce its work efficiency and accuracy. Also, long-time quarantine causes the death of environmentally sensitive ornamental fish and huge financial losses. To improve existing quarantine systems, information on ornamental fish was collected and structured, and a server was established to develop quarantine performance support software equipped with a text search engine. However, the long names of ornamental fish in general can cause many typos and time bottlenecks when we type search words for the target fish information. Therefore, we need a technique that can correct typos. Typical typo character calibration compares input text with all characters in a calibrated candidate text dictionary. However, this approach requires computational power proportional to the number of typos, resulting in slow processing time and low calibration accuracy performance. Therefore, to improve the calibration accuracy of characters, we propose a fusion system of simple Artificial Neural Network (ANN) models and character preprocessing methods that accelerate the process by minimizing the computation of the models. We also propose a typo character generation method used for training the ANN models. Simulation results show that the proposed typo character correction system is about 6 times faster than the conventional method and has 10% higher accuracy.

• 한국식품영양과학회지
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• 제27권3호
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• pp.386-392
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• 1998

Experiments were carried out to establish an effective artificial drying method of Pacific saury (Cololabis seira) to kwamaegi. Raw fish containing 67% moisture were dried up to containing less than 40% moisture by drying for 15 days. The fish lost moisture more rapidly during first 3 days of natural drying than artificial drying. Total lipid content increased from 16.1% to 30.3 and 29.8% by 15 days of natural and artificial drying, respectively. Neutral lipid occupying 91.63% of total lipid increased to 92~94% during 15 days of drying, while content of phospholipid and glycolipid decreased slightly. The values of peroxide and thiobarbituric acid increased up to 6 days of drying and then did not change. Peroxide levels were lower in artifically dried fish than in naturally dried ones.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.429-434
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• 2007

This paper presents an experimental and parametric study of a biomimetic fish robot actuated by the Lightweight Piezo-composite Actuator(LIPCA). The biomimetic aspects in this work are the oscillating tail beat motion and shape of caudal fin. Caudal fins that resemble fins of BCF(Body and Caudal fin) mode fish were made in order to perform parametric study concerning the effect of caudal fin characteristics on thrust production at an operating frequency range. The observed caudal fin characteristics are the shape, area, and aspect ratio. It was found that a high aspect ratio caudal fin contributes to high swimming speed. The fish robot was propelled by artificial caudal fins shaped after thunniform-fish and mackerel caudal fins, which have relatively high aspect ratio, produced swimming speed as high as 2.364 cm/s and 2.519 cm/s, respectively, for 300 Vpp input voltage excited at 0.9 Hz. Thrust performance of the biomimetic fish robot was examined by Strouhal number, Froude number, Reynolds number, and Net forward force.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권12호
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• pp.4866-4888
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• 2020

One major and time-consuming task in fish production is obtaining an accurate estimate of the number of fish produced. In most Nigerian farms, fish counting is performed manually. Digital image processing (DIP) is an inexpensive solution, but its accuracy is affected by noise, overlapping fish, and interfering objects. This study developed a catfish recognition and counting algorithm that introduces detection before counting and consists of six steps: image acquisition, pre-processing, segmentation, feature extraction, recognition, and counting. Images were acquired and pre-processed. The segmentation was performed by applying three methods: image binarization using Otsu thresholding, morphological operations using fill hole, dilation, and opening operations, and boundary segmentation using edge detection. The boundary features were extracted using a chain code algorithm and Fourier descriptors (CH-FD), which were used to train an artificial neural network (ANN) to perform the recognition. The new counting approach, based on the geometry of the fish, was applied to determine the number of fish and was found to be suitable for counting fish of any size and handling overlap. The accuracies of the segmentation algorithm, boundary pixel and Fourier descriptors (BD-FD), and the proposed CH-FD method were 90.34%, 96.6%, and 100% respectively. The proposed counting algorithm demonstrated 100% accuracy.

• 한국수산과학회지
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• 제47권3호
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• pp.283-291
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• 2014

This study assessed dominant fish species, and the characteristics and spatio-temporal distribution of fish schools using acoustic and catch data in the marine ranching area (MRA) of Yeosu in July and August 2013. Acoustic data were collected using a 200-kHz dual beam transducer, and catch data were analyzed through auction data generated by a set net installed in the MRA. More fish schools were detected by acoustic methods in July than in August. The temporal distribution of fish schools differed between July and August, but, many schools demonstrated a high mean volume scattering strength (SV) around artificial reefs. Additionally, the characteristics of fish schools detected by echograms and the species caught by set nets differed between July and August. The dominant fish species were Engraulis japonicus, Pampus argenteus, Scomberomorus niphonius, and Pampus echinogaster in July, and approximately 85% of the catch in August consisted of Scomberomorus niphonius. Therefore, hydro-acoustic tools are useful for estimating fish school characteristics in large areas over a short period. To determine species, it is important to conduct net sampling surveys during the acoustic surveys. However, if a database of fish school characteristics organized by species is constructed through continuous study, it could be possible to identify fish species through acoustic methods alone.

• 한국수산과학회지
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• 제53권4호
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• pp.628-636
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• 2020

Streptococcosis in the olive flounder Paralichthys olivaceus can be caused by Streptococcus parauberis. We compared three routes of administration for experimental injections of the S. parauberis 19FBSPa0003 strain in the olive flounder. Pathological changes were observed during the experimental infection. Inflammation of the serous membrane in the liver, intestine, spleen and heart was the major pathological change found in the infected olive flounder. No mortality was observed in fish that received intraperitoneal (IP) injection at less than 1×10⁴ colony-forming unit (CFU)/fish. The lethal dose 50 for olive flounder, given an intravenous (IV) injection, was 7.94×10⁴ CFU/fish. Fish with a higher concentration of IV injected S. parauberis (1×10⁸ CFU/fish) died within a maximum of two days. However, serious necrosis and bacterial proliferation in ellipsoidal cells of the spleen and heart tissues were found in moribund or dead fish, 1-2 days after IV injection. Similar histopathological signs were observed in olive flounder inoculated by subcutaneous (SC) infected and naturally infected. In addition, SC was also strongly associated with bacteria concentration and cumulative mortality rate. Based on these results, SC is the recommended method for artificial infection by S. parauberis in the olive flounder.

• 센서학회지
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• 제30권1호
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• pp.30-35
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• 2021

To operate an underwater robot in an environment with fluid flow, it is necessary to recognize the speed and direction of the fluid and implement motion control based on these characteristics. Fish have a lateral line that performs this function. In this study, to develop an artificial lateral line sensor that mimics a fish, we developed a method to measure the flow speed and the incident angle of the fluid using a pressure sensor. Several experiments were conducted, and based on the results, the tendency according to the change in the flow speed and the incident angle of the fluid was confirmed. It is believed that additional research can aid in the development of an artificial lateral line sensor.

• 해양환경안전학회지
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• 제19권4호
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• pp.309-314
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• 2013

인공용승류 해역에서 난자치어의 종조성 및 시공간 변동을 파악하기 위하여 2012년 6월 13일, 9월 21일 및 25일에 난자치어 네트를 이용하여 조사하였다. 조사기간 동안 출현한 어란은 4,849 ind./$1,000m^3$, 자치어는 641 ind./$1,000m^3$이였다. 출현한 어란 중 가장 우점한 종은 멸치(Engraulis japonicus)로써 총 출현량의 약 57.5 %를 차지하였다. 그 외 미동정(Unidentified) 어란 I, II, III, IV이 출현하였다. 자치어는 청베도라치(Pictiblennius yatabei)가 가장 우점하였으며, 그 다음으로 돛양태류(Repomucenus sp.A, sp.B), 고등어(Scomber japonicus), 멸치(Engraulis japonicus), 전어(Konosirus punctatus) 등의 순으로 나타났다. 그리고 미동정(Unidentified) 자치어 I, II가 출현하였다. 대조구 해역에서는 어란은 멸치, 자치어는 돛양태류가 출현하였다. 시기별 변동에서는 어란 및 자치어 모두 7월에 가장 많았으며, 8월에 가장 낮았다. 정점별 변동에서는 인공용승이 일어나는 인근 정점인 2, 3번에서 어란 및 자치어의 출현량이 가장 많았다. 대조구 해역과의 비교하여 정점당 약 4배 이상 많은 어란 및 자치어가 출현하였다. 인공용승에 의한 영양염류 및 먹이생물의 증가로 인하여 어란 및 자치어의 출현량이 증가한 것으로 판단된다.

• 수산해양기술연구
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• 제51권1호
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• pp.16-25
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• 2015

Visual census and hydro-acoustic survey was carried out at Ulju small scale marine ranching area (MRA) to estimate demersal fish aggregations on September and November 2013. In this hydro-acoustic survey, the authors combined an image sonar with a scientific echo sounder to monitor an underwater situation and compare two acoustic data. Consequently, visual census survey was useful to estimate fish species composition for hydro-acoustic survey, because it is easy to identify aggregated fish species and overcome limits on a fishing depth and ability of an conventional fishing gear like a bottom gill-net or a fish trap at marine ranching area. Mean fish density was estimated as $0.757g/m^2$ on September and $0.219g/m^2$ on November and Fish abundance was finally calculated as 1.51ton (coefficient of variation, CV=13.1%) on September and 0.44ton (CV=47.7%) on November, respectively. Hydro-acoustic survey combined with the image sonar was useful to monitor fish aggregations and estimate fish stocks around artificial reefs at shallow coastal MRA. We were able to easily identify the underwater structures like an artificial reef and a fishing rope as well as fish aggregations from image sonar data. Therefore, the method was effective to separate unwanted echo signals in acoustic data of scientific echo sounder.

• 생태와환경
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• 제40권1호
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• pp.103-109
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• 2007

2005년 6월부터 11월까지 팔당호의 경안천 수역에 설치한 인공수초섬을 대상으로 인공수초섬(AVI)영향권역과 자연수초군락지 (NVA) 그리고 비수초대 (VFA)에서 어류의 분포를 조사하여 인공수초섬이 어류 분포에 미치는 영향을 조사하였다. 조사기간 중 인공수초섬 영향권에서는 11과 23속 24종의 어류가 채집되었고 자연수초군락지에서도 같은 수준인 24종의 어류가 채집되었으나 비수초대에서는 6과 11속 12종의 어류만이 채집되었다. 세조사지점 모두 잉어과 어종이 절대 우점하였으며 인공수초섬 영향권역과 자연수초군락지에서는 소형 어종인 S. japonicus coreanus가 극우점하는 현상을 보였다. 반면 비수초대에서는 중대형 회유성 어종인 H. labeo와 E. erythropterus가 개체수를 기준으로 할 때 58%를 차지하고 있었으며 소형어종은 전혀 채집되지 않았다. 우점도지수는 인공수초섬 영향권역과 자연수초대에서 높게 나타났으며 다양도지수와 균등도는 비수초대에서 높게 나타났고 종풍부도는 인공수초섬 영향권역에서 높게 나타났다. 한국고유종으로는 A. gracilis, S. variegatus wakiyae, S. japonicus coreanus 및 O. interrupta 등이 채집되었으며 외래어종은 C. cuvieri를 포함하여 생태계교란외래생물종으로 지정된 L. macrochirus와 M. salmoides등이 출현하였다. 본 조사의 결과 인공수초섬이 자연수초군락지와 비슷한 수준으로 어류 산란처 및 서식처로써 역할을 할 수 있음을 확인하였다.