• 제어로봇시스템학회논문지
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• 제14권3호
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• pp.248-253
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• 2008

This paper presents a sensing system for smart home which can detect an location transition events such as entrance/exit of a member and identify the user in a group at the same time. The proposed system is compose of two sub-systems; a wireless sensor network system and a database server system. The wireless sensing system is designed as a star network where each of sensing modules with ultrasonic sensors and a Bluetooth RF module connect to a central receiver called Bluetooth access point. We propose a method to discriminate a user by measuring the height of the user. The differences in the height of users is a key feature for discrimination. At the same time, the each sensing module can recognize whether the user goes into or out a room by using two ultrasonic sensors. The server subsystem is a sort of data logging system which read the detected event from the access point and then write it into a database system. The database system could provide the location transition information to wide range of context-aware applications for smart home easily and conveniently. We evaluate the developed method with experiments for three subjects in a family with the installation of the developed system into a real house.

• Journal of Electrical Engineering and Technology
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• 제6권1호
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• pp.81-85
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• 2011

The end effect of a linear induction motor (LIM) has been known for several decades, especially in high speed operation. The exit part of the primary is not dealt as extensively as the entry part because of its minor effect. However, the exit part is one of the keys to weaken the dolphin effect, which occurs in high speed operation. In this paper, the concept of the virtual primary core is introduced, and chamfering of the primary outlet teeth is proposed to minimize the longitudinal end effect at the exit zone. For this, LIM for the high-speed train is designed and analyzed by using finite element method. Results confirm that chamfering can improve thrust performance effectively.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2007년도 동계학술발표대회 논문집
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• pp.322-327
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• 2007

Dedicated outdoor air-conditioning(DOA) system that utilizes pre-cooling and desiccant dehumidification can be superior to conventional cooling and reheating system with respect to energy consumption and indoor thermal comfort. In this work, simulation has been conducted to study various factors that affect the performance of DOA. Dynamic simulation shows the transient variation of temperature and humidity as the on/off control logic is imposed. Exit humidity of process air and flow rate are varied to study the effect on exit temperature of process air, dehumidification quantity, required regeneration temperature and exit humidity of regeneration air. For an outdoor air condition of $28.5^{\circ}C$ temperature, 16 g/kg humidity ratio and 2000 cmh flow rate, the dehumidification efficiency is increased by 4.6% as the flow rate is doubled.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2005년도 추계학술대회 논문집
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• pp.1063-1070
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• 2005

Number of subway train units that Seoul Metropolitan Subway Corporation as at September 2005 is 1.944 on 4 routes from 60 units at the time of commencement of operation, having grown exponentially. Along with increase in the number of passengers the role of subway as safer and expedient means of transportation is now being required. Furthermore, the Corporation has been researching on means of improving the safety and reliability of subway entry/exit doors which has become an essential task and directly effect the safety of the passengers. In this Study, has developed sensory control system for the entry/exit door of the subway train using non-contact proximity sensor as a part of review of and measures against various issues of entry/exit door of the subway trains currently under operation. In addition, this sensor system was verified through test production and tests. If this technology becomes commercialized and practically utilized in the future, it would be able to make definite contribution to the safer transportation of passengers.

• 한국자동차공학회논문집
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• 제16권4호
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• pp.88-96
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• 2008

Effects of the duct inlet guide vane on the flowrate distribution characteristics of the defroster nozzle exit in a defrost duct system were investigated experimentally to design the optimum heating, ventilation and air conditioning (HVAC) system applied in an automotive compartment. A 3-dimensional hot-wire anemometer system was used to measure the velocity field in the vicinity of the defroster nozzle jet flow and the velocity distributions near the windshield interior surface. At first, two cases of with- and without-duct inlet guide vanes were considered as the test condition, and then three cases of the duct inlet guide vane were tested to determine the optimum guide vane shape and their positions. The arrangement of the duct inlet guide vanes has an effect on the improved flowrate distribution at the defroster nozzle exit and near the windshield interior surface. However, the application of the lots of guide vane to control the flow direction leads to increase the flow resistance, resulting in the decreased flowrate issuing from the defroster nozzle. The shape of the duct inlet guide vane affects not only the flowrate distribution between the driver side and the assistant driver side but also the reduction of the flow resistance in the defrost duct system.

• 한국분무공학회지
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• 제4권4호
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• pp.38-45
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• 1999

The near field structure of round turbulent jets with initially asymmetric velocity distribution is investigated experimentally. Experiments were carried out using a constant temperature hot-wire anemometry system to measure streamwise velocity in the jets. The measurements were undertaken across the jet at various streamwise stations in a range starting from the jet exit plane and up to a downstream location of twelve diameters. The experimental results include the distribution of mean and instantaneous velocities, vorticity field, turbulence intensity, and the Reynolds shear stress. The asymmetry of the jet exit plane was obtained by using circular cross-section pipes with a bend at the upstream of the exit. Three pipes were used for this study: A straight pipe, 90 and 160 degree-bended pipes. Therefore, at the upstream of the pipe exit, the secondary flow through the bend and the mean streamwise velocity distribution could be controlled by changing the curvature of pipes.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 추계학술대회논문집B
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• pp.634-639
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• 2001

The current study addresses experimental and computational work of impulse wave discharged from the exit of two kinds of right-angle pipe bends, which are attached to the open end of a simple shock tube. The weak normal shock wave with its magnitude of Mach number from 1.02 to 1.20 is employed to obtain the impulse wave propagating outside the exit of the pipe bends. A Schlieren optical system visualizes the impulse wave discharged from the exit of the pipe bends at an instant. The experimental data of the magnitude of the impulse wave and its propagating directivity are analyzed to characterize the impulse waves discharged from the exit of the pipe bends and compared with those discharged from a straight pipe. Computational results well predict the experimented dynamic behaviors of the impulse wave. The results obtained show that a right-angle miter bend considerably reduces the magnitude of the impulse wave and its directivity toward to the pipe axis, compared with the straight pipe and right-angle smooth bend. It is believed that the right-angle miter bend pipe can playa role of a passive control against the impulse wave.

• 한국소음진동공학회논문집
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• 제12권12호
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• pp.943-949
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• 2002

The propagation of the impulse wave discharged from the Inclined exit of a pipe is investigated through shock tube experiment and numerical computations. The pressure histories and directivities of the impulse wave propagating outside from the exit of pipe with several different configurations are analyzed for the range of the incident shock wave Mach number between 1.1 and 1.4. In the shock tube experiments, the impulse waves are visualized by a Schlieren optical system for the purpose of validation of computational work. Computations using the two-dimensional. unsteady, compressible, Euler equations are carried out to represent the experimented impulse waves. Computed Schlieren images predict the experimented impulse waves with a good accuracy. The results obtained show that for the radial direction the peak pressure of the impulse wave discharged depends upon the Inclined angle of the exit of the pipe. but for the axial direction it is almost constant regardless of the inclined angle of the pipe exit.

• 자원ㆍ환경경제연구
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• 제18권1호
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• pp.1-22
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• 2009

ITQ 제도의 목적은 어업에 투자된 과도한 자본을 줄여 어자원의 남획을 막는데 있다. 그 동안 ITQ 제도는 가장 비용 효율적이지 못한 어선들부터 자신들의 쿼터를 처분함으로써 스스로 시장에서 퇴출하도록 하는 효과를 가져올 것으로 믿어져 왔다. 그러나 본 논문은 실물옵션 기법을 도입, 퇴출 비용에 비가역성이 존재할 경우 덜 비용 비효율적인 어선들이 먼저 퇴출 결정을 내릴 수도 있다는 것을 보여준다. 즉, 퇴출에 따르는 비용이 비용 비효율적인 정도에 비례하고 비가역적인 성격을 갖는다고 할 때, 퇴출에 지연 동기가 발생한다는 점을 반영하여, 오히려 자본이 과도하게 투자된 어선 보다 그렇지 않은 어선이 먼저 퇴출하게 될 수도 있다는 것을 보여준다. 마지막으로 본 논문이 현실적으로 제공하는 정책적인 함의 또한 기술하였다.

• 한국컴퓨터정보학회논문지
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• 제27권8호
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• pp.9-21
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• 2022

이 논문에서 우리는 제4차 산업혁명의 핵심기술의 하나인 LiDAR 센서를 기반으로 기존 검지 카메라의 검지율을 개선하여 입출차 차량에 대해 100% 검지가능한 시스템을 개발하였다. 현재 운영 중인 주차장은 98% 정도의 차량번호 인식율에만 의존하고 있으므로 입출차 카운트의 불일치, 부정확한 정보 제공 등으로 사전 예약불가, 실시간 주차정보 불일치 등 여러 가지 문제를 안고 있다. 주차현황정보는 정확도 100% 수준으로 관리되어야 하며 이를 위해 우리는 LIDAR를 이용하여 주차장의 입출차 검지 체계를 구축하였다. 주로 자율주행 자동차의 차량 및 사물검지를 위해 필수적으로 사용되고 있는 LIDAR 센서를 응용하여 주차시스템을 개발하는 경우, 검지된 센싱 정보로 차량 입출차 정보의 정확성과 입출차 카운트의 신뢰도를 개선할 수 있다. LIDAR의 분해능은 100%로 보장이 되었고 주차장의 입차(+), 출차(-) 차량의 합계가 0이 되도록 구현할 수 있었다. 우리는 3,000대의 실제 주차장 출입 차량으로 테스트해 본 결과 주차 차량 입출차 정확도를 100%로 결과를 도출하였다.