• 수산해양기술연구
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• 제44권1호
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• pp.1-9
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• 2008

This study aims to reduce the bycatch of young fishes and other species in the octopus(Octopus vulagris, Octopus dolfleini) trap fishery on the East Sea, Korea. We carried out field experiments and tank experiments to verify the fishing efficiency and bycatch with the different 8 types of trap. 4 of them had mesh size 20, 35, 55 respectively and 75mm, 2 of them with escape ring of diameter 30mm and 50mm and 2 of them with escape device. The gap was 20 and 40mm respectively. The mesh sizes of the traps with ring and frame were 20mm. The traps with mesh size 20 and 35mm were not reasonable because it could fish under 300g octopus as bycatch which is not permitted by the Korean fisheries regulations. The catch number of octopus over 300g by traps with escape ring of diameter 30mm was 53. The catch of trap with mesh size 20mm was 54. The catch of trap with mesh size 35mm was 53. There is no significant difference among them. The catch number of octopus over 500g that is fishermen's favorite one was 46 in the trap with escap ring. The diameter of was 30 mm and the catch of trap with mesh size 20mm was more 3 catch and the catch of trap with mesh size 35mm had 6 more catch. Fishermen wanted to catch over 500g octopus because the octopuses had commercial value. The traps with escape ring can be replaceable with he traps with mesh size 20 or 35mm because the trap is suitable to conserve the octopus resources and keep the fishermen's fishing substantiality.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.120.5-120
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• 2001

This paper introduces an Adapative Goal Pertubation Method(AGPM) for mobile robots which can move safely without being locked in a trap situation. AGPM is a modified method of VFH(Vector Field Histrogram) that Borenstein has proposed. AGPM consists of Avoid-Trap-Mode, Escape-Trap-Mode and Check-Trap-Mode. Some results of the mobile robot that have 8 ultrasonic sensors are shown through simulations.

• 한국화재소방학회:학술대회논문집
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• 한국화재소방학회 2010년도 춘계학술논문발표회 논문집
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• pp.322-330
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• 2010

초고층 건축물의 급속한 증가는 건축물 화재 시 고층에서 보다 빨리 피난할 수 있는 구조적 피난설비를 요구한다. 기존의 구조용 완강기나 구조대는 고층에서는 피난자의 공포감을 충분히 해소하기에 역 부족이었다. 이러한 문제점을 보완한 성능을 갖추어 동시에 다수의 피난자를 대피시킬 수 있는 새로운 피난기구가 요구되고 있다. 이에 고층에서도 동시에 여러 사람이 안전하고, 신속하게 피난층까지 무사히 대피가 가능한 유압식 피난기구를 고안하고, 개략 설계하게 되었다. 이 연구를 기초로 향후 상세설계를 마친 후 고층 건축물에 적용되어 안전한 피난기구가 되었으면 한다.

• 환경생물
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• 제40권3호
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• pp.335-340
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• 2022

2017년 9월 부산 감만부두에서 국내 최초로 붉은불개미(Solenopsis invicta)가 검출된 이후, 농림축산검역본부에서는 외래개미류의 유입가능성이 높은 지역에 대해 주기적 예찰을 수행하고 있다. 그러나 현재 사용 중인 개미류 예찰용 트랩들은 개미가 들어갔다가 다시 쉽게 빠져나오거나, 토양이 없는 단단한 바닥 환경에서는 설치하기가 어려운 단점이 있다. 이를 해결하기 위해 다단협관을 이용하여 탈출이 어렵고, 콘크리트 같은 곳에서도 쉽게 설치가 가능한 신형 트랩을 개발하게 되었다. 신형 트랩은 함정트랩에 비해 4배 이상의 개미류 포획효과를 가지고 있으며, 포획된 개미들의 재탈출을 효과적으로 차단하는 것을 확인하였다. 새로 개발된 트랩을 통해 외래개미류의 국내 침입을 효과적으로 차단하기를 기대한다.

• Tribology and Lubricants
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• 제36권6호
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• pp.359-364
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• 2020

Numerical investigation of the groove trap effect with variation in the groove-edge radius of curvature is presented here. The trap effect is evaluated in a two-dimensional sliding bearing using computational fluid dynamics (CFD). This simulation is based on the discrete phase model (DPM) and standard k - ε turbulence model using commercial CFD software, FLUENT. The numerical results are evaluated by comparisons with streamlines and particle trajectories in the grooves. Grooves are applied to various lubrication systems to improve their lubrication characteristics, such as load carrying capacity increment, leakage reduction, frictional loss reduction, and preventing three-body abrasive wear due to trapping effect. This study investigates the grove trapping effect for various groove-edge radius of curvature values and Reynolds numbers. The particle is assumed to be made of steel, with a circular shape, and is injected as a single particle in various positions. One-way coupling is used in the DPM model because the single particle injection condition is applied. Further, the "reflect" condition is applied to the wall boundary and "escape" condition is used for the "pressure inlet" and "pressure outlet" boundaries. From the numerical results, the groove edge radius is found to influence the groove trap effect. Moreover, the groove trap effect is more effective when applying the groove edge radius.

• 한국인구학
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• 제11권1호
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• pp.32-49
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• 1988

The social conditions in Koreas until 1950s were similar to the model phenomena of low level eqilibrium trap which was named by Prof. Nelson, with the continuation of high population growth rate and low economic growth rate. To escape from the trap, Korean government adopted two different policies, one is economic development plans and the other is family planning programs. Theses policies were successful in both increasing the national products and decreasing the population growth rate. In 1985 per capita GNP increased to over two thousand dollars, fertility rate reduced to replacement level(2.1) and unemployment rate was stabilized at 4 percent level. From various prospects, we were successfully escaped from the Malthusian trap and many economists, who studied developed countries, belive that population growth has positive effects on technological progress, economies of scale, specialization, individual attitude on work, and economic growth. Therefore we need to reexamine the anti-natalistic population policy of Korea in this situation.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.2461-2466
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• 2003

This paper presents a simple sensor fusion algorithm using neural network for navigation of mobile robots with obstacle avoidance and trap recovery. The multiple sensors input sensor data to the input layer of neural network activating the input nodes. The multiple sensors used include optical encoders, ultrasonic sensors, infrared sensors, a magnetic compass sensor, and GPS sensors. The proposed sensor fusion algorithm is combined with the VFH(Vector Field Histogram) algorithm for obstacle avoidance and AGPM(Adaptive Goal Perturbation Method) which sets adaptive virtual goals to escape trap situations. The experiment results show that the proposed low-level fusion algorithm is effective for real-time navigation of mobile robot.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 D
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• pp.1989-1990
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• 2006

This paper presents an escaping route method in a trap situation (a case that the robot is trapped in a local minimum by the potential of obstacles). In this scheme, the APFs for path planning have a multiplicative and auditive configuration between APFs for goal destination and APFs for obstacle avoidance unlike conventional configuration where APFs for obstacle avoidance is added to APFs for goal destination. The virtual escaping route method is proposed to allow a robot to escape from a local minimum in trap situation where the total forces composed of repulsive forces by obstacles and attractive force by a goal are zero.

• 노동경제논집
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• 제23권2호
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• pp.81-106
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• 2000

1990년대 중반 이후 비정규직의 급증은 우리 나라 노동시장의 변화를 보여주는 중요한 특정이다. 본고는 우리 나라의 비정규직이 근로자들에게 막다른 일자리인지 아니면 정규직으로 옮겨가는 과정에서 일시적으로 경험하게 되는 곳인지를 분석하고 있다. 이에 대한 이해는 노동시장을 분석하고 정책을 수립하는 데에 중요한 시사점을 제공할 것이다. 본 연구는 정태적인 측면과 동태척인 측면에서 이 문제에 접근하고 있다. 정태적인 측면만 보더라도 비정규직 종사자들은 주로 취약계층에 속하는 사람들로서 낮은 직무능력과 기능을 요구하는 분야에 종사하고 있어서 우리 나라의 비정규직은 함정일 가능성이 크다. 본고는 동태분석을 통해 이러한 가능성을 확인함과 동시에 보다 분명하고 구체척인 증거들을 제시하고 있다. 결국 우리나라의 비정규직은 주로 함정으로 역할을 하며 가교로서의 역할은 미미하다.

• Tribology and Lubricants
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• 제32권3호
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• pp.101-105
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• 2016

Trap effect of groove is evaluated in a lubricating system using computational fluid dynamics (CFD) analysis. The simulation is based on the standard k-ε turbulence model and the discrete phase model (DPM) using a commercial CFD code FLUENT. The simulation results are also capable of showing the particle trajectories in flow field. Computational domain is meshed using the GAMBIT pre-processor. The various grooves are applied in order to improve lubrication characteristics such as reduction of friction loss, increase in load carrying capacity, and trapping of the wear particles. Trap effect of groove is investigated with variations in cross-sectional shape and Reynolds number in this research. Various cross-sectional shapes of groove (rectangular, triangle, U shaped, trapezoid, elliptical shapes) are considered to evaluate the trap effect in simplified two-dimensional sliding bearing. The particles are assumed to steel, and defined a single particle injection condition in various positions. The “reflect” boundary condition for discrete phase is applied to the wall boundary, and the “escape” boundary condition to “pressure inlet” and “pressure outlet” conditions. The streamlines are compared with particles trajectories in the groove. From the results of numerical analysis in the study, it is found that the cross-sectional shapes favorable to the creation of vortex and small eddy current are effective in terms of particle trapping effect. Moreover, it is found that the Reynolds number has a strong influence on the pattern of vortex or small eddy current in the groove, and that the pattern of the vortex or small eddy current affects the trap effect of the groove.