• 한국컴퓨터정보학회논문지
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• 제27권11호
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• pp.181-190
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• 2022

이 논문에서 우리는 기존의 영상식 또는 루프식 좌회전 감응 시스템과는 달리 라이다(LiDAR)센서 및 영상 카메라를 이용하여, 좌회전 대기 차량을 2중으로 검지하고 좌회전 차선의 대기 길이에 대응하는 좌회전 교통신호체계를 효율적으로 부여할 수 있는 시스템을 소개하였다. LiDAR 센서에 의해 송수신된 LiDAR 신호에 대해서는 실시간으로 좌회전 대기 차량을 검지하고, 영상 카메라에 의한 영상에 대해서는 실시간 또는 일정한 주기별로 분석하도록 구성함으로써 불필요한 연산 처리를 절감시켜 실시간 감응 처리가 가능하도록 하였다. 실제 신호처리기를 이용한 교차로 시뮬레이션으로 1주일 동안 매일 5시간 성능 테스트를 해 본 결과 기존 방식에 비해 3%~5% 향상된 99.9%의 검지율을 기록하였다. 장점으로는 LiDAR 센서로 99.9% 좌회전 대기 차량이 검지되었으며 의도적인 검지 누락을 발생시키더라도, 영상에 의한 자체 보정을 통해 즉각적인 대응이 가능하여 좌회전 대기 차량의 과도한 대기시간을 조절시켜 교차로 내 모든 차선의 교통흐름을 원활하게 유도할 수 있었다. 또한 좌회전 차량이 뜸한 외곽의 교차로에 적용 시 불필요한 신호 비용을 줄이는 등 서비스 신뢰도 및 효율성을 높일 수 있다.

• 한국건축시공학회지
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• 제17권6호
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• pp.483-492
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• 2017

최근 국내에서는 다양한 형태로 연안이 개발되고 있다. 이에 따라 안전사고를 예방하고 경관을 저해시키지 않는 새로운 소파블록의 개발이 요구되고 있다. 회파블록은 상부가 평탄하여 친수공간으로 활용이 가능하지만, 구조 내부에 존재하는 회파관으로 인해 중량손실이 발생한다. 따라서 이에 대응하기 위해 중량콘크리트를 사용하여 파랑 저항성을 상승시킬 필요성이 있다. 이러한 목적을 위하여 본 연구에서는 동슬래그 및 자철석을 골재로 사용한 중량 콘크리트를 개발하고 이의 염해저항성을 평가하였다. 연구 결과에 따르면, 일반 골재와 중량골재를 각각 혼입한 콘크리트의 28일 압축강도는 큰 차이가 발생하지 않았으나, ASTM C1202에 의한 염소이온침투저항성 시험 시 자철석을 혼입한 콘크리트는 과도한 전류의 흐름으로 평가가 불가능한 것으로 나타났다. 그러나 염소이온의 침투깊이를 이용하는 NT Build 492 시험에서는 ASTM C 1202 시험법에서 관찰된 문제점 없이 실험 진행이 가능하였고, 동슬래그, 자철석을 골재로 사용한 중량 콘크리트의 염소이온침투저항성이 가장 우수한 것으로 나타났다. 따라서 동슬래그 및 자철석을 골재로 사용한 중량콘크리트는 회파블록에 적용이 가능할 것으로 판단된다.

• 한국정밀공학회지
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• 제32권12호
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• pp.1031-1037
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• 2015

Laser assisted machining (LAM) is an effective method with which to effectively process difficult-to-cut materials. Simple machining processes, such as turning and linear tool paths, have been studied by many researchers. But, there are few research efforts on LAM workpieces using threedimensional shapes because of difficulties controlling the laser heat on workpieces with inclined angles or curved surfaces. Two methods for machining three-dimensional workpieces are proposed in this paper. The first is that the heat source shape and laser focal length are maintained using an index table. Second, a rotary type laser module is controlled using an algorithm to move the laser heat source in all directions. This algorithm was developed to control the rotary type laser module and the machine tool simultaneously. These methods are verified by a CATIA simulation.

• ETRI Journal
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• 제35권6호
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• pp.1029-1037
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• 2013

This paper introduces a novel and fast synthesizing method for 3D motions of quadrupedal animals that uses only a small set of motion capture data. Unlike human motions, animal motions are relatively difficult to capture. Also, it is a challenge to synthesize continuously changing animal motions in real time because animals have various gait types according to their speed. The algorithm proposed herein, however, is able to synthesize continuously varying motions with proper limb configuration by using only one single cyclic animal motion per gait type based on the biologically driven Froude number. During the synthesis process, each gait type is automatically determined by its speed parameter, and the transition motions, which have not been entered as input, are synthesized accordingly by the optimized asynchronous motion blending technique. At the start time, given the user's control input, the motion path and spinal joints for turning are adjusted first and then the motion is stitched at any speed with proper transition motions to synthesize a long stream of motions.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1998년도 연구회 합동 학술발표회 논문집
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• pp.44-48
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• 1998

In the buck-boost DC-DC converter which is used at a certain situation such as in factories where loads often change a lot, the switches in the device make big energy loss in operating at Buck-Boost Mode due to hard switching and are affected by lots of stresses which decrease the efficiency rate of the converter. In order to improve this problem, to decrease the loss of snubber and switching, it has been investigated that zero voltage switching mode and zero current switching mode which make the operation of switches with soft switching. For the more sophisticated and advanced device, this paper is presented the Partial Resonant Soft Switching Mode Power Converter which is adapted the power converter having the partial resonant soft switching mode, that makes switches operate when the resonant current or voltage becomes zero by making the resonant circuit partially at turning on and off of the switches with suitable layout of the resonant elements and switch elements in the converter. Also, this paper includes the analysis and simulation of the Partial Resonant type Buck-Boost Chopper.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.581-584
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• 2003

The austenitic STS 304 stainless steel was turned to clarify the effects of tool geometry on the tool wear. The wear of TiN-TiCN-TiC-TiAlN coated tungsten carbide tool was the smallest, exhibiting larger wear in the order of Si-Al-O-N ceramic, TiN coated tungsten carbide, TiN-TiCN-TiN coated tungsten carbide, TiC-TiN cermet and M20 tungsten carbide tools at the same cutting conditions. The S-type tool of M20 with large approach angle showed the longest tool life of all tools used in this tests due to preventing the groove wear of the side cutting edge. The wear of the S-type tool with the rake angle of 15$^{\circ}$became smaller than with that of -5$^{\circ}$, but the tool with the nose radius of 0.8mm did not perform much better with increasing the rake angle.

• 대한산업공학회지
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• 제26권2호
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• pp.165-170
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• 2000

In order to perform a successful material cutting process, the operators are to select the suitable machining tools and cutting conditions for the cutting environment. Up to now, this has been a complicated procedure done by the data in the tool manufacturers' paper catalog and the operator's experiencial knowledge, so called heuristics. This research is motivated by the fact that using computer techniques in processing vast amount of data and information, the operator can determine the tool and cutting condition easily. In the developed program, the selection of milling cutter, insert, and components are combined to provide optimal cutting speed, depth of cut, feed rate, rpm, and power. This program also provides the selection routine for end mill, drilling, turning, and grinding where the suitable tools are selected by workpiece, holder type, cut type, and insert shape.

• Journal of Biosystems Engineering
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• 제22권4호
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• pp.497-502
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• 1997

Automation facilities of greenhouses have been continuously developed. However, the conventional two-stage worm gear reducer reveals some problems, including low transmission efficiency. The worm gear reducer also have some difficulties in manufacturing and short life. Therefore, this study was performed to develop a planetary gear reducer, having a high Sear reduction ratio and high torque transmission efficiency. The planetary gear system consisted of a fixed ring gear and a 2-teeth differential ring gear turning slow, as the planetary pinion orbits fast around the fixed ring gear. The developed gear system can achieve a high speed reduction rate at one stage. The reducing system was employed to the greenhouse ventilation system. The reducer has the transmission efficiency of 70.5%, 2∼3 times longer life time, and twofold roll-up torque at an affordable price, comparing with conventional reducers. This reducer can be also applied to many industrial equipments, such as industrial crane, hoist, elevator and gondola etc.

• Journal of Biosystems Engineering
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• 제17권1호
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• pp.45-54
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• 1992

A wireless control system was designed and constructed to control the rice transplanter of walking type with remote control. VHF(very high freqency) was sent from wireless transmitter to wireless reciever by usig 6 channels to control main clutch, steering clutch, plant lever and throttle lever within 200 meter distance between remote control and rice transplanter. The rice transplanter with wireless control system showed good performance for accuracy of travel speed, traveling mobility and turning diameter in the concrete, paddy and dry field. It is concluded that the developed wireless control system could be adapted to control not only conventional rice transplanters but also most of the agricultural machine by changing some parts of the control system.

• Journal of Ship and Ocean Technology
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• 제3권3호
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• pp.25-44
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• 1999

Estimation efficiencies according to different sea trial are investigated in connection with sensitivity analysis, and new trial method is proposed which can improve the estimation efficiency of hydrodynamic derivatives. MMG Equation with Kijima's formula is used for simulation. Extended Kalman Filter is chosen for estimation technique and hydrodynamic derivatives of interest is limited to 12 of those in sway and yaw equations. Esso Osaka is selected for the test ship. Sensitivity analysis and estimation results based on conventional trials show that a more sensitive derivative gives more efficient estimation result. Sensitivities of nonlinear derivatives become pronounced in the trial where steady condition lasts longer such as turning test, while sensitivities of linear derivatives gas a larger values in the trial where unsteady condition lasts longer such as 10deg-10deg zigzag test. Consequently, in new method , named S-type trial, steady and unsteady condition are combined appropriately to increase sensitivities. Linear derivatives are estimated better in S-type trial and the estimation of nonlinear derivatives is improved to extent.