• 한국도로학회논문집
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• 제11권2호
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• pp.217-228
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• 2009

연속류도로 합류영향구간에서는 본선과 다른 교통특성을 가진 연결로교통류의 합류로 차로변경 및 가감속과 같은 차량간의 불규칙한 상호작용이 발생하여 교통류의 난류현상을 야기한다. 따라서, 난류현상은 운행상태를 고려하여 연속된 지점간의 불안정한 교통특성으로 판단하여야 한다. 본 연구에서는 합류영향구간에 차로-지점별 검지기를 설치하여 시공간적으로 연속된 교통자료를 구축하였으며, 지점간에 유의한 속도변화를 판단하는 기준으로 최소유의차(LSD) 통계값을 산정하여 난류현상을 분석하였다. 분석결과, 합류영향구간 난류현상은 운행상태에 따라 발생권역 및 심각도가 변화되는 것으로 나타났다. 이에 따라 난류현상에 의한 최대 합류영향권역은 교통량이 증가하는 혼잡전 운행상태에서 보여지며, 속도변화특성에 따라 상류 100m$\sim$하류 100m의 "감속구간"과 하류 100m$\sim$하류 400m의 "감속속도유지 및 가속구간"으로 구분할 수 있었다.

• 대한교통학회지
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• 제24권2호
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• pp.127-137
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• 2006

돌발상황이 발생하였을 경우 발생장소를 기준으로 상류부와 하류부에서는 교통류의 특성이 서로 다르게 나타난다 즉, 상류부에는 저속으로 운행하는 높은 밀도의 교통류가 그리고, 하류부에는 고속으로 운행하는 낮은 밀도의 교통류가 형성되는 것이다. 본 연구에서는 이러한 특성을 이용하여 돌발발생 장소의 상 하류부 검지기 간의 속도와 밀도의 차이를 시간적, 공간적으로 동시에 고려한 돌발감지기법을 제시하였다 따라서 본 연구에서는 기존에 운영되고 있는 비교기법에 속하는 돌발감지기법들이 점유율 단독 또는 점유율과 운행속도의 추세를 별개로 분석한 후 두 개 지표의 변화추세를 고려한 것에 비하여 검지기 간의 거리 및 속도와 밀도를 동시에 고려 할 수 있는 개념을 제시하는데 그 의의가 있다. 천안-논산고속도로의 사고 상황 자료를 바탕으로 off-line 상에서 본 기법을 적용한 결과 인접 검지기 간의 속도-밀도관계를 분석함으로서 사고위치와 검지기간의 관계 등을 포함한 돌발상황을 감지할 수 있었다. 향후 본 기법이 고속도로교통관리시스템(FTMS)의 돌발감지기법(AID)으로 적용되기 위해서는 광범위한 자료를 바탕으로 돌발을 판정할 수 있는 임계치, 사고의 파장정도 및 돌발발생장소와 검지기 간의 위치에 따른 변화추이 등에 대한 추후 연구가 필요할 것으로 판단된다.

• 자동차안전학회지
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• 제5권1호
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• pp.16-24
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• 2013

Some GM (General Motors) vehicles are using a GMLAN (General Motors Local Area Network) communication protocol for control and diagnostics. The airbag control module uses vehicle speed information from the GMLAN to record the vehicle speed as pre-crash information. In order to use the vehicle speed information for crash reconstruction purposes, it helps to be able to understand the accuracy of the data. The actual vehicle speed is not expected to be the same as the GMLAN indicated speed in some situations like a spin or if there is hard braking. This paper compares the actual vehicle speed and vehicle speed information during specific vehicle maneuvers. Actual vehicle speed is calculated from a GPS sensor, while GMLAN vehicle speed is calculated from transmission output sensor by the Engine control module (ECM). Vehicle maneuvers defined as Mode #1, Mode #2, Mode #3. The Mode #1 maneuver simulates wheel lock-up and skidding f by hard-braking at a specific speed. The Mode #2 maneuver simulates a 90degree turn using a J-turn maneuver at a specific speed. The Mode#3 maneuver simulates a 180 degree turn using a spin type of maneuver at a specific speed. The study then compares the GMLAN speed and GPS speed to see what speed difference exists between them. The results of this paper are applicable to GM vehicles only. This paper catalogs the performance and limitations of two vehicles as useful reference for crash reconstructions where there is a need to understand the speed indicated in the pre-crash section of the SDM data.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 춘계학술대회 논문집
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• pp.377-383
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• 2011

The paper is to perceive accurately speed of the train through redundant processor operation. When Slip/slide is occurred at the axle, the train is applied brake force using the Tachometer and the Doppler sensor which assistance equipment. One of the main features of railway signaling system is that rolling stock is made stop to avoid collision with the rolling stock ahead when the rolling stock exceeds its maximum operating speed in line. In addition, in the case of the rolling stock with automatic train operation, it carries out activities such as braking and propulsion using the difference between its actual speed and target speed at the point. To perform these functions, it is essential to calculate the exact speed of the rolling stock in signaling equipment on vehicles. Train speed detection unit are composed of the Tachometer and the Doppler sensor, and speed information is sent to the SDU unit. The processor of SDU unit calculates the speed of the train using compare logic the received speed information. Even if there are Slip/Slide, signaling system is available to apply exact braking, to improve stop on position and to guarantee the safety of trains.

• 한국지능시스템학회논문지
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• 제24권4호
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• pp.366-371
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• 2014

본 논문에서는 정격풍속 이상에서 발전량을 일정하게 유지하기 위하여 회전속도의 변화율을 이용한 신경망 피치제어기가 제안되었다. 제안된 신경망 피치제어기는 발전기의 정격 회전속도와 현재 회전속도의 차이를 기본정보로 사용하고 추가적으로 발전기 회전속도의 변화율을 사용하였다. 시뮬레이션은 Matlab/simulink에서 수행되었으며, 시뮬레이션을 통해 제안된 피치제어기를 사용한 풍력발전기는 발전기의 정격 회전속도인 122.9[rad/s]로 잘 유지 되는 것을 확인하였다.

• 한국소음진동공학회논문집
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• 제27권1호
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• pp.57-64
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• 2017

This study was reviewed the noise reduction effects with installation of 'point to point speed camera' for controlling the speed of the car. The multiple regression analysis was performed to know how the relationship between the noise level and these parameters, such as measured traffic volume and rate of heavy vehicle and weighted average speed was changed with and without the 'point to point speed camera'. In the analysis results shows that the less traffic volume, the more noise reduction effect has been increased and the more traffic volume, the more noise reduction effect has been reduced. And noise reduction effects by the 'point to point speed camera' was different from each measured point. The cause of the difference was determined that inadequate 'point to point speed camera' position to see the effect of noise reduction. It is determined to require a more study to improve the noise reduction effects of the 'point to point speed camera' such as the camera position adjustment.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.694-699
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• 2005

This paper deals with a control technique of eliminating the transient vibration of a geared mechanical system. This technique is based on a model-based control with a rotational speed sensor in order to establish the damping effect at the driven machine part. A rotational speed sensor is installed in a driven gear, namely a bull gear. A control model is composed of a reduced-order mechanical part expressed as a transfer function between the rotational speed of the motor and that of the bull gear. This control model estimates a load speed after the rotational speed of the bull gear is acted on the transfer function. The difference between the estimated load speed and the motor speed is calculated dynamically and it is added to the velocity command to suppress the transient vibration generated at the load. This control technique is applied to a dies driving spindle of a form rolling machine. In this paper, the performance of this control method is examined by simulations. The settling time of the residual vibration generated at the loading inertia can be shortened down to about 1/2 of the uncompensated vibration level.

• 한국정밀공학회지
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• 제28권6호
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• pp.687-693
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• 2011

Spring-mass models have been widely accepted to explain the basic dynamics of human gait. Researchers found that the leg stiffness increased with gait speed to increase energy efficiency. However, the difference of leg stiffness change with gait speed between the young and the elderly has not been verified yet. In this study, we calculated the lower limb stiffness of the elderly using walking model with an axial spring. Vertical stiffness was defined as the ratio of the vertical force change to the vertical displacement change. Seven young and eight elderly subjects participated to the test. The subjects walked on a 12 meter long, 1 meter wide walkway at four different gait speeds, ranging from their self-selected speed to maximum speed randomly. Kinetic and kinematic data were collected using three force plates and motion capture cameras, respectively. The vertical stiffness of the two groups increased as a function of walking speed. Maximum walking speed of the elderly was slower than that of the young, yet the walking speed correlated well with the optimal stiffness that maximizes propulsion energy in both groups. The results may imply that human may use apparent limb stiffness to optimize energy based on spring-like leg mechanics.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 추계학술대회 논문집
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• pp.304-307
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• 2002

High speed machining was accomplished. through the technological advances which covers the whole field of mechanical industry. But tapping have many troubles because of its complicate cutting mechanism, for example. tool damage, chip elimination and synchronization between spindle rotation and feed motion. But High speed tapping is so important that it marches in step with the flow of the times and make improvement in the productivity. In this paper we analyze mechanism of high speed synchronized tapping with the signal of tapping torque and spindle speed obtained through the newly developed high speed tapping machine(NTT-30B). We made an experiment with this machine on condition of various speed from 1000rpm to 10000rpm. As one complete thread is performed through the whole chamfer cutting, cutting torque increases highly in chamfer cutting, but smoothly in full thread cutting functioning of the threads guide. And the size of cutting torque according to spindle speed(rpm) was not enough of a difference to be conspicuous.

• 한국식품과학회지
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• 제54권2호
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• pp.247-250
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• 2022

노화 등으로 인한 식빵의 굳기(toughness) 정도를 측정하고자 Miller/Hoseney Toughness 장치를 이용하여 여러 측정조건(이동속도 및 침투율 변화)에서 절단력 최대값을 측정하여 분석하였다. 식빵 겉껍질에서는 이동속도가 증가함에 따라 절단력 최대값이 유의적으로 증가하였으며, 시료들 사이에서의 유의차는 일부 측정조건에서 다르게 나타났다. 식빵 내부에서의 측정값은 동일 침투율에서는 이동속도가 증가함에 따라 대부분의 시료에서 절단력 최대값이 유의적으로 증가하였으며, 시료들 사이에서의 유의차는 침투율에 상관없이 이동속도가 달라져도 변화하지 않았다. 결론적으로 본 실험 방법으로 식빵 내부의 굳기를 측정할 경우 측정조건변화에 의해 절단력 최대값은 달라지나, 시료간 유의차는 변화하지 않아, 시료간 유의차를 판단하는 경우 본 실험 범위내에서 매우 편리하고 신뢰도가 높은 실험으로 사료된다.