• 제목/요약/키워드: swimming velocity

검색결과 44건 처리시간 0.021초

해저설치형 음향도플러유향유속계를 이용한 음향산란층의 연직이동속도 측정 (Measurement of vertical migration speed of Sound Scattering Layer using an bottom mooring type Acoustic Doppler Current Profiler)

  • 조현정;이경훈
    • 수산해양기술연구
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    • 제46권4호
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    • pp.449-457
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    • 2010
  • This study shows that the vertical migration speed of sound scattering layers (SSLs), which is distributed in near Funka Bay, were measured by 3D velocity components acquired from a bottom moorng ADCP. While the bottom mooring type has a problem to measure the velocity vectors of sound scattering layer distributed near to surface, both the continuous vertical migration patterns and variability of backscatterers were routinely investigated as well. In addition, the velocity vectors were compared with the vertical migration velocity estimated from echograms of Mean Volume Backscattering Strength, and estimated to produce observational bias due to SSLs which is composed of backscatterers such as euphausiids, nekton, and fishes have swimming ability.

수영 출발동작의 지면반력 차이 비교 II (A Comparison of Ground Reaction Force of High School Swimmers in Accordance with Starting Motions)

  • 김규완
    • 한국운동역학회지
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    • 제17권3호
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    • pp.69-80
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    • 2007
  • The purpose of this study was to investigate the difference of ground reaction forces of swimming athletes during their starting motion and to find out the most effective starting motions which were used in swimming athletes. The subjects were 9 male and 8 female high school swimming athletes who were athletic career over 7 years and used three starting motions in competition. The ground reaction forces were measured from each athletes performing three starting motion each of the open grap starting motion, closed grap starting motion and track starting motion. For the measurement, the force platform of AMTI company was utilized, and the analysis on measured ground reaction forces were used of Biosoft(Ver. 1.0). The items measured were stance time, Fz max deceleration force and Fz max deceleration force time, Fz mid stance force and Fz mid stance force time, Fz max acceleration force and Fz max acceleration force time, Torque maximum and Torque maximum time, Torque average, Excursion along Y axis of center of pressure of foot, Excursion along X axis of center of pressure of foot, Length of center of pressure of foot, Average velocity of center of pressure of foot. The data measured by the closed grap starting motion, open grap starting motion and track starting motion were analyzed by one-way repeated ANOVA. The results were as follows ; 1. The Fz max deceleration force time, Fz mid stance force, Fz max acceleration force, Torque maximum and Torque maximum time, Excursion along Y axis of center of pressure of foot, Average velocity of center of pressure of foot were significantly fast and large in the closed grap starting motion then open grap starting motion and track starting motion. 2. The Excursion along Y axis of center of pressure of foot was significantly long in the closed grap starting motion then open grap starting motion and track starting motion.

Abnormal behaviour in rock bream (Oplegnathus fasciatus) detected using deep learning-based image analysis

  • Jang, Jun-Chul;Kim, Yeo-Reum;Bak, SuHo;Jang, Seon-Woong;Kim, Jong-Myoung
    • Fisheries and Aquatic Sciences
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    • 제25권3호
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    • pp.151-157
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    • 2022
  • Various approaches have been applied to transform aquaculture from a manual, labour-intensive industry to one dependent on automation technologies in the era of the fourth industrial revolution. Technologies associated with the monitoring of physical condition have successfully been applied in most aquafarm facilities; however, real-time biological monitoring systems that can observe fish condition and behaviour are still required. In this study, we used a video recorder placed on top of a fish tank to observe the swimming patterns of rock bream (Oplegnathus fasciatus), first one fish alone and then a group of five fish. Rock bream in the video samples were successfully identified using the you-only-look-once v3 algorithm, which is based on the Darknet-53 convolutional neural network. In addition to recordings of swimming behaviour under normal conditions, the swimming patterns of fish under abnormal conditions were recorded on adding an anaesthetic or lowering the salinity. The abnormal conditions led to changes in the velocity of movement (3.8 ± 0.6 cm/s) involving an initial rapid increase in speed (up to 16.5 ± 3.0 cm/s, upon 2-phenoxyethanol treatment) before the fish stopped moving, as well as changing from swimming upright to dying lying on their sides. Machine learning was applied to datasets consisting of normal or abnormal behaviour patterns, to evaluate the fish behaviour. The proposed algorithm showed a high accuracy (98.1%) in discriminating normal and abnormal rock bream behaviour. We conclude that artificial intelligence-based detection of abnormal behaviour can be applied to develop an automatic bio-management system for use in the aquaculture industry.

일개 실내수영장의 공기 중 염소 및 트리할로메탄의 노출평가 및 환기 효율 평가 (Assessment for Inhalation Exposure to Trihalomethanes (THMs) and Chroline and Efficiency of Ventilation for an Indoor Swimming Pool)

  • 박해동;박현희;신정아;김태호
    • 한국환경보건학회지
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    • 제36권5호
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    • pp.402-410
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    • 2010
  • The objectives of this study were to evaluate the air quality surrounding an indoor swimming pool, to estimate the cancer risk based on the airborne exposure to trihalomethanes (THMs), and to examine the ventilation efficiency by Computational Fluid Dynamics (CFD). Chlorine and THMs were measured poolside, and in the staff room and reception area. The indoor swimming pool was modeled using the Airpak program, with ventilation drawings and actual survey data. Temperature, flow and mean age of the air were analyzed. Levels of chlorine poolside, and in the staff room, and reception area were $203\;{\mu}g/m^3$, $5\;{\mu}g/m^3$, and $10\;{\mu}g/m^3$, respectively. Chloroform was the dominant THM in all sampling sites and mean concentrations were $16.30\;{\mu}g/m^3$, $0.51\;{\mu}g/m^3$, and $0.06\;{\mu}g/m^3$ poolside, in the staff room and reception area, respectively. Bromodichloromethane and Dibromochloromethane levels were respectively estimated as $10.3\;{\mu}g/m^3$ and $1.7\;{\mu}g/m^3$ poolside, $1.3\;{\mu}g/m^3$ and $0.1\;{\mu}g/m^3$ in the staff room, and were not detected in the reception area. The cancer risks from inhalation exposure to THMs were estimated between $3.37{\times}10^{-7}$ and $1.84{\times}10^{-5}$. A short circulation phenomenon was observed from the supply air vents to the exhaust air vents located in the ceiling. A high temperature layer was formed within one meter of the ceiling, and a low temperature layer was formed under this layer due to the low velocity and high temperature of the supply air, and the improper locations of the supply air vents and exhaust air vents. The stagnation was evident at the above adult pool and the mean age of the air was 22 minutes. Disinfection by-products in the indoor swimming pool were present in higher concentrations than in the outdoor air. In order to increase the removal of pollutants, adjustment was required of the supply air volume and the supply/exhaust position.

꼬리 지느러미의 유연성을 이용한 로봇 돌고래의 성능 향상 (Improving the Performance of a Robotic Dolphin with a Compliant Caudal Fin)

  • 박용재;조규진
    • 로봇학회논문지
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    • 제9권4호
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    • pp.225-231
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    • 2014
  • Fish generates thrust with a compliant fin which is known to increase the efficiency. In this paper, the performance of a robotic dolphin, the velocity and the stability, was improved using an optimal compliant caudal fin under certain oscillating frequency. Optimal compliance of the caudal fin exists that maximizes the thrust at a certain oscillating frequency. Four different compliant fins were used to find the optimal compliance of the caudal fin at a certain frequency using the half-pi phase delay condition. The swimming results show that the optimal compliant fin increases the velocity of the robotic fish. The compliance of the caudal fin was also shown to improve the stability of the robotic fish. A reactive motion at the head of the robotic dolphin causes fluctuation of the caudal fin. This phenomenon increases with the oscillating frequency. However, compliant fin reduced this fluctuation and increased the stability.

원격어군탐지기의 시작 및 그 응용에 관한 연구 -II -낭장망 입망어군의 원격관측- (Studies on the Trial Manufacture of Telesounder and its Application (2) - Remote Observations of Fishes Entering in the Gape Nets With Wings -)

  • 이원우
    • 수산해양기술연구
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    • 제31권1호
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    • pp.54-62
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    • 1995
  • 해상에서 어군의 행동과 분포상태를 탐지하여 그 정보를 원격으로 전송하기 위한 원격어군탐지기를 시험제작하고, 이들을 이용하여 서해의 고군산군도 연안에서 1994년 8월 8일, 18일~19일 및 9월 8~9일에 낭장망에 입망하는 어군의 유영층과 그 어획변동 등을 조사하고, 원격어군탐지기의 실용성을 평가하여 분석, 고찰한 결과는 다음과 같다. 1. 어획어종은 12종이었으며, 멸치(Engraulis japonica), 꼴뚜기(Loligo beka), 밴댕이(Harengula zunasi) 등이 전 어획량의 95%이상을 차지하였다. 2. 해상이 동국에서 탐지한 어군탐지기의 기록과 그것을 원격으로 전송한 선상고정국의 어군기록은 매우 잘 일치하였다. 3. 멸치는 유속이 0.6kt 이하로서 유속변화가 적은 경우에 어획이 많았으며, 유속이 0.6kt이상인 때에는 적어지는 경향을 나타내었다. 4. 어군의 유영층은 유속이 1kt이하에서 얕아지는 경향이 있었으며, 유속이 1kt이상이고 유속변화가 커지면 유영층에 큰 변동이 없으며, 이때 평균깊이는 약 4m였다. 5. 1회 조업당 어획량은 10~30 kg이었으며, 유향과 어구의 부설방향이 일치하지 않거나 유속이 너무 강해지면 어획이 적음을 알 수 있었다. 이상의 결과와 같이 본 연구에서 시험제작한 원격어군탐지기는 낭장망어업에서 어군의 행동과 분포에 관한 어업정보를 파악하는데 유효하게 사용할 수 있음이 확인되었다.

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유체역학적 집속 효과를 이용한 단일 박테리아 주화성의 정량적 분석 (Quantitative Analysis of Single Bacterial Chemotaxis Using a Hydrodynamic Focusing Channel)

  • 전호정;이용구;진송완;구상모;이창수;유정열
    • 대한기계학회논문집B
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    • 제31권3호
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    • pp.209-216
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    • 2007
  • Bacterial chemotaxis is essential to the study of structure and function of bacteria. Although many studies have accumulated the knowledge about chemotaxis in the past, the motion of a single bacterium has not been studied much yet. In this study, we have developed a device microfabricated by soft lithography and consisting of microfluidic channels. The microfluidic assay generates a concentration gradient of chemoattractant linearly in the main channel by only diffusion of the chemicals. Bacteria are injected into the main channel in a single row by hydrodynamic focusing technique. We measured the velocity of bacteria in response to a given concentration gradient of chemoattractant using the microfludic assay, optical systems with CCD camera and simple PTV (Particle Tracking Velocimetry) algorithm. The advantage of this assay and experiment is to measure the velocity of a single bacterium and to quantify the degree of chemotaxis by statistically analyzing the velocity at the same time. Specifically, we measured and analyzed the motility of Escherichia coli strain RP437 in response to various concentration gradients of L-aspartate statistically and quantitatively by using this microfluidic assay. We obtained the probability density of the velocity while RP437 cells are swimming and tumbling in the presence of the linear concentration gradient of L-aspartate, and quantified the degree of chemotaxis by analyzing the probability density.

두 종류 공기주입식 카약 보트의 성능 비교 및 선수 수행력 비교 분석 (A Comparative Analysis of Two Inflatable Kayak's Effect on Players and Kayak Performances)

  • 이종훈;박용현;남기정
    • 한국체육학회지인문사회과학편
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    • 제53권2호
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    • pp.531-540
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    • 2014
  • 본 연구는 두 종류의 공기주입식 카약 보트의 성능 비교와 함께 선수들의 카약 전방 스트로크 동작의 차이점을 비교 분석하여 보다 효율적이고 안전한 카약 보트를 찾는 데 목적이 있다. 이를 위해 대한 체육회 소속 K 고등학교 엘리트 남자 선수 5명이 연구에 참여하였으며, K고 실내 수영장에서 실험을 실시하였다. 보트의 성능 평가를 위해 보트 속도, 보트 좌우 흔들림 각도 차이, 보트의 회전 평균 각속도를 산출하였으며 선수의 수행력 차이를 분석하기 위해 몸통의 회전 가동범위, 무릎 관절의 굴곡-신전 가동범위, 몸통의 최대 회전 각속도, 무릎관절의 최대 신전 각속도, 상하지 근육의 활성도를 산출하였다. 연구 결과 선수들의 수행력 평가 변인에서는 통계적으로 유의한 수치를 보이지 않았다. 보트의 성능 평가 변인에서는 보트의 속도에서 B보트가 통계적으로 유의하게 빨랐으며 다른 변인들은 통계적으로 유의한 차이를 보이지 않았다. 결국 길이가 상대적으로 길고 폭이 상대적으로 좁은 B보트는 A보트와 비교했을 때 비슷한 안전성을 갖고 있으면서 보다 효율성을 나타내었다.

Modeling the Selectivity of the Cod-end of a Trawl Using Chaotic Fish Behavior and Neural Networks

  • Kim, Yong-Hae;Wardle, Clement S.
    • Fisheries and Aquatic Sciences
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    • 제11권1호
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    • pp.61-69
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    • 2008
  • Using empirical data of fish performance and physiological limits as well as physical stimuli and environmental data, a cod-end selectivity model based on a chaotic behavior model using the psycho-hydraulic wheel and neural-network approach was established to predict fish escape or herding responses in trawl and cod-end designs. Fish responses in the cod-end were categorized as escape or herding reactions based on their relative positions and reactions to the net wall. Fish movements were regulated by three factors: escape time, a visual looming effect, and an index of body girth-mesh size. The model was applied to haddock in a North Sea bottom trawl including frequencies of movement components, swimming speed, angular velocity, distance to net wall, and the caught-fish ratio; simulation results were similar to field observations. The ratio of retained fish in the cod-end was limited to 37-95% by optomotor coefficient values of 0.3-1.0 and to 13-67% by looming coefficient values of 0.1-1.0. The selectivity curves generated by this model were sensitive to changes in mesh size, towing speed, mesh type, and mesh shape.

Rh2-enriched Korean Ginseng Ameliorates Chronic Fatigue in a Forced Exercise mouse model

  • Kim, Won-Yong;Lee, Jin-Seok;Yoo, Hwa-Seung;Son, Chang-Gue
    • 대한한의학회지
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    • 제37권2호
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    • pp.76-84
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    • 2016
  • Objectives: We evaluated the anti-fatigue effects of Rh2-enriched Korean ginseng (Ginseng Rh2+) using a forced exercise-induced chronic fatigue mouse model. Methods: ICR male mice were subjected to running wheel for 1 h, 5 days/week during 4 weeks, and running velocity was gradually increased. Each running session was followed by oral administration of distilled water, Ginseng Rh2+ (150 or 300 mg/kg), or N-acetyl-L-cysteine (NAC, 100 mg/kg) 1 h later. The exercise tolerance and forced swimming test were performed to evaluate the fatigue condition. Results: Chronic forced exercise reduced the physical activity, as evidenced by the behavioral tests, which were notably ameliorated by Ginseng Rh2+ treatment. Ginseng Rh2+ treatment also attenuated the alterations of energy metabolism and oxidative stress in skeletal muscle tissues and/or sera, including malondialdehyde (MDA), lactate concentration and its related factors (lactate dehydrogenase, blood urea nitrogen, and glucose levels). Conclusion: These findings strongly suggest that Ginseng Rh2+ exerts a potent anti-fatigue effect through modulation of energy metabolism and oxidative response.