• 신재생에너지
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• 제17권4호
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• pp.1-8
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• 2021

To determine the wind turbine class in the offshore of the Korean Peninsula, the reference wind speed for a 50-y return period at the hub height of a wind turbine was estimated using the reanalysis data sets. The most recent reanalysis data, ERA5, showed the highest correlation coefficient (R) of 0.82 with the wind speed measured by the Southwest offshore meteorological tower. However, most of the reanaysis data sets except CFSR underestimated the annual maximum wind speed. The gust factor of converting the 1 h-average into the 10 min-average wind speed was 1.03, which is the same as the WMO reference, using several meteorological towers and lidar measurements. Because the period, frequency, and path of typhoons invading the Korean Peninsula has been changing owing to the climate effect, significant differences occurred in the estimation of the extreme wind speed. Depending on the past data period and length, the extreme wind speed differed by more than 30% and the extreme wind speed decreased as the data period became longer. Finally, a reference wind speed map around the Korean Peninsula was drawn using the data of the last 10 years at the general hub-height of 100 m above the sea level.

• Smart Structures and Systems
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• 제20권2호
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• pp.197-205
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• 2017

The dynamic performance of railway bridges under high-speed trains draws the attention of bridge engineers. The vibration issue for long-span bridges under high-speed trains is still not well understood due to lack of validations through structural health monitoring (SHM) data. This paper investigates the correlation between bridge acceleration and train speed based on structural dynamics theory and SHM system from three foci. Firstly, the calculated formula of acceleration response under a series of moving load is deduced for the situation that train length is near the length of the bridge span, the correlation between train speed and acceleration amplitude is analyzed. Secondly, the correlation scatterplots of the speed-acceleration is presented and discussed based on the transverse and vertical acceleration response data of Dashengguan Yangtze River Bridge SHM system. Thirdly, the warning indexes of the bridge performance for correlation scatterplots of speed-acceleration are established. The main conclusions are: (1) The resonance between trains and the bridge is unlikely to happen for long-span bridge, but a multimodal correlation curve between train speed and acceleration amplitude exists after the resonance speed; (2) Based on SHM data, multimodal correlation scatterplots of speed-acceleration exist and they have similar trends with the calculated formula; (3) An envelope line of polylines can be used as early warning indicators of the changes of bridge performance due to the changes of slope of envelope line and peak speed of amplitude. This work also gives several suggestions which lay a foundation for the better design, maintenance and long-term monitoring of a long-span high-speed bridge.

• 한국정밀공학회지
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• 제20권3호
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• pp.58-65
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• 2003

Vehicle acceleration data from an accelerometer and wheel speed data from standard, 50-tooth antilock braking system wheel speed sensors are used to estimate the absolute longitudinal speed of a vehicle. We develop the four velocity estimation algorithms. And we compare experimental results with the Butterworth filtered speed from the fifth wheel and find that it is possible to estimate absolute longitudinal vehicle speed during a hard braking maneuver lasting three seconds.

• 한국콘텐츠학회논문지
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• 제20권4호
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• pp.25-37
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• 2020

교통 혼잡으로 인한 사회적 비용이 증가하면서 도로 속도를 예측하기 위한 다양한 연구들이 진행되고 있다. 도로 속도 예측의 정확도를 향상시키기 위해서는 교통 돌발 상황을 고려할 필요가 있다. 본 논문에서는 교통 돌발 상황을 고려한 도로 속도 예측 기법을 제안한다. 제안하는 기법은 연결된 도로들이 미치는 영향을 반영하기 위해서 예측 도로의 속도 데이터 뿐만 아니라 연결된 도로들의 속도 데이터도 이용한다. 또한, 돌발 상황으로 인한 혼잡을 예측하기 위해 속도의 변화량을 분석한다. 연결된 도로와 타겟 도로의 속도 데이터를 LSTM의 입력 데이터로 이용하여 1차적으로 도로 속도를 예측한다. 교통 돌발 상황으로 도로의 규칙적인 흐름이 깨지며 발생하는 예측 오차를 줄이기 위해 이벤트 가중치를 적용하여 최종적으로 도로 속도를 예측한다. 다양한 성능 평가를 통해 제안된 방법의 우수성을 입증한다.

• 한국우주과학회:학술대회논문집(한국우주과학회보)
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• 한국우주과학회 2008년도 한국우주과학회보 제17권2호
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• pp.37.2-37.2
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• 2008

Korea-Japan Joint VLBI Correlator (KJJVC), to be used for Korean VLBI Network (KVN) in Korea Astronomy & Space Science Institute (KASI), is a high-speed calculator that outputs the correlation results in the maximum speed of 1.4GB/sec.To receive and record this data keeping up with this speed and with no loss, the design of the software running on the data archive system for receving and recording the output data from the correlator is very important. But, the simple kind of programming using just single thread that receives data from network and records it by turns, can cause a bottleneck effect while processing high speed data and a probable data loss, and cannot utilize the merit of hardwares supporting multi core or hyper threading, or operating systems supporting these hardwares. In this talk we summarize the design of the data transfer software for KJJVC and high speed, large capacity data archive system using general socket programming and multi threading techniques, and the pre-BMT(Bench Marking Test) results from the tests of the storage product providers' proposals using this software.

• 대한전자공학회논문지SD
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• 제46권7호
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• pp.1-6
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• 2009

본 논문은 DRAM에서 DBI (Data Bus Inversion)를 이용한 새로운 방식의 High Speed 아키텍쳐를 설명하고자한다. DBI는 SSO와 LSI와 같은 잘 알려진 문제를 감소시키기 위한 방식중의 하나이다. 본 논문에서는 Analog Majority Voter(AMV), DBI Flag에 의한 GIO 제어회로, 새로운 SSO Algorithm과 같은 많은 아키텍쳐들이 Data Bus의 천이(Toggle) 개수를 줄이기 위해서 제안되었다. DBI Flag에 의해 GIO데이터 반전 여부를 결정되기 때문에 파워 소모가 감소될 수 있고, 데이터 Eye diagram도 40ps이상 증가될 수 있게 되었다. 제안된 DBI Scheme을 이용하였을 때 High speed 동작에서 거의 안정한 SI특성을 얻을 수 있게 됐다. 90nm CMOS Technology를 이용하여 제조되었다.

• 제어로봇시스템학회논문지
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• 제7권1호
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• pp.1205-1210
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• 2001

This paper describes a methodology using neural network to compensate the nonlinear error of deriving speed for electric differential system included in electric vehicle. An electric differential system which drives each of the left and right wheels of the electric vehicle independently. The electric vehicle driven by induction motor has the nonlinear speed error which depends on a steering angle and speed command. When a vehicle drives along a curved road lane, the speed unblance of inner and outer wheels makes vehicles vibration and speed reduction. To compensate for the speed error, we collected the speed data of the inner wheel and outer wheel in various speed and the steering angle data by using an manufactured electric vehicle and the real system. According to the analysis of the acquisited data, we designed the differential speed control system based on a speed error compensator using neural network.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 춘계학술대회 논문집
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• pp.132-139
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• 2011

ATP(Automatic Train Protection) system in railroad signalling system is on-board signalling system which is controlled by train control information such as location and speed of trains. Safety is ensured by transmitting the train control information between on-board and wayside device in the ATP system. When an engineer disregards the speed limit on a tachometer, the train is automatically stopped by the on-board device. Recently, the studies of increasing speed of the train have been developed. Eurobalise in ERTMS/ETCS system is used in case that speed of trains is up to 500[km/h]. A study of safety braking distance is needed by increasing the speed of train in the ATP system. Train data and track data are required to calculate the safety braking distance. The train data includes formations of trains, length of trains, service brake and emergency brake etc. Also, the track data includes slope of track, curve of track, length of track, speed limit etc. In this paper, the speed profile is computed by analyzing the train and track data in the ATP system. It is demonstrated by applying to subway line 2 in Seoulmetro through the on-site test.

• 한국방재학회:학술대회논문집
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• 한국방재학회 2008년도 정기총회 및 학술발표대회
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• pp.85-88
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• 2008

Damage from typhoon disaster can be mitigated by grasping and dealing with the damage promptly for the regions in typhoon track. What is this work, a technique to analyzed dangerousness of typhoon should be presupposed. This study estimated 10m level wind speed using 700hPa wind by typhoon, referring to GPS dropwindsonde study of Franklin(2003). For 700hPa wind, 30km resolution data of Regional Data Assimilation Prediction System(RDAPS) were used. For roughness length in estimating wind of 10m level, landuse data of USGS are employed. For 10m level wind speed of Typhoon Rusa in 2002, we sampled AWS point of $7.4\sim30km$ distant from typhoon center and compare them with observational data. The results show that the 10m level wind speed is the estimation of maximum wind speed which can appear in surface by typhoon and it cannot be compared with general hourly observational data. Wind load on domestic buildings relies on probability distributions of extreme wind speed. Hence, calculated 10m level wind speed is useful for estimating the damage structure from typhoon.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 심포지엄 논문집 정보 및 제어부문
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• pp.148-151
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• 2005

This paper proposes a high speed interface using redundant multi-valued logic for high speed communication ICs. This circuit is composed of encoding circuit that serial binary data are received and converted into parallel redundant multi-valued data, and decoding circuit that convert redundant multi-valued data to parallel binary data. Because of the multi-valued data conversion, this circuit makes it possible to achieve higher operating speeds than that of a conventional binary logic. Using this logic, a 1:4 demultiplexer (DEMUX, serial-parallel converter) IC was designed using a 0.35${\mu}m$ standard CMOS Process. Proposed demultiplexer is achieved an operating speed of 3Gb/s with a supply voltage of 3.3V and with power consumption of 48mW. Designed circuit is limited by maximum operating frequency of process. Therefore, this circuit is to achieve CMOS communication ICs with an operating speed greater than 3Gb/s in submicron process of high of operating frequency.