• 한국산학기술학회논문지
• /
• 제16권8호
• /
• pp.5534-5540
• /
• 2015

철도 신호제어시스템에서 열차의 위치 및 점유 유무를 검지하기 위하여 궤도회로 이외에 axle counter적용 사례가 증가하고 있는 추세이다. 이에 본 연구에서는 열차검지 및 차축계수의 신뢰성을 높이기 위해 axle counter의 센서 방식을 지자기 센서 방식과 근접센서 방식을 비교하였으며, 그에 따른 차이점과 결과를 제시하였다. 또한, 정확한 차축검지를 위한 센서부의 취부조건 등을 고려한 설치에 대해 현장 경험을 기반으로 적용된 결과를 제시한다. 본 연구에서는 차축검지의 신뢰성 향상을 위해 센서의 위상차를 판단할 수 있도록 설계 변경한 결과 차축검지 기능뿐만 아니라 다양한 기능까지(열차의 방향검지, 열차속도검지 등) 수행할 수 있는 확장성을 확보하였다. 또한 열차의 종별, 무게 등의 특성에 종속되지 않았으며, 자체적으로 제작한 차축검지를 위한 모의차축 이송장치와 Test Bed를 구축하여 Lab. 테스트를 수행한 결과 350km/h의 속도에서도 차축 검지의 누락이 발생하지 않았음을 확인하였다. 이를 통해 열차의 검지뿐만 아니라 통과하는 열차의 속도와 편성 수, 선로전환기 통과 시 철사쇄정 조건 그리고 건널목 장치에도 적용할 수 있는 기반을 마련하였으며, 향후 철도 신호제어 시스템 전반에 확대 적용하게 되면 열차안전운행에 많은 기여를 할 것으로 판단된다.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제15권10호
• /
• pp.3608-3626
• /
• 2021

The detection of bolts is an important task in high-speed train inspection systems, and it is frequently performed to ensure the safety of trains. The difficulty of the vision-based bolt inspection system lies in small sample defect detection, which makes the end-to-end network ineffective. In this paper, the problem is resolved in two stages, which includes the detection network and cascaded classification networks. For small bolt detection, all bolts including defective bolts and normal bolts are put together for conducting annotation training, a new loss function and a new boundingbox selection based on the smallest axis-aligned convex set are proposed. These allow YOLOv3 network to obtain the accurate position and bounding box of the various bolts. The average precision has been greatly improved on PASCAL VOC, MS COCO and actual data set. After that, the Siamese network is employed for estimating the status of the bolts. Using the convolutional Siamese network, we are able to get strong results on few-shot classification. Extensive experiments and comparisons on actual data set show that the system outperforms state-of-the-art algorithms in bolt inspection.

• International Journal of Railway
• /
• 제3권3호
• /
• pp.106-112
• /
• 2010

Accidents at level crossing have large portion on train accidents, and causes economical loss by train delay and operational interruption. Various safety equipments are employed to reduce the accident at level crossing, but existing warning device, and crossing barrier are simple train-oriented protection equipments. In this paper, intelligent railway level crossing system is proposed to prevent and reduce accidents. For train driver's prompt action, image of level crossing and obstacle warning message are continuously provided to train driver through wireless communication in level crossing control zone. Obstacle warning messages, which are extracted by computer vision processing of captured image at level crossing, are recognized by train driver through message color, flickering and warning sound. It helps train driver to decide how to take an action. Meanwhile, for vehicle driver's attention, location and speed of approaching train are given to roadside equipments. We identified the effect of proposed system through test installation at Sea train and Airport level crossing of Yeong-dong line.

• 전기학회논문지
• /
• 제66권5호
• /
• pp.870-876
• /
• 2017

In this paper, we proposed the automatic vision inspection system using multi-layer perceptron to detect the defects occurred on rail surface. The proposed system consists of image acquisition part and analysis part. Rail surface image is acquired as equal interval using line scan camera and lighting. Mean filter and dynamic threshold is used to reduce noise and segment defect area. Various features to characterize the defects are extracted. And they are used to train and distinguish defects by MLP-classifier. The system is installed on HEMU-430X and applied to analyze the rail surface images acquired from Honam-line at high speed up to 300 km/h. Recognition rate is calculated through comparison with manual inspection results.

• Smart Structures and Systems
• /
• 제29권3호
• /
• pp.421-431
• /
• 2022

Concrete slab cracks monitoring of modern high-speed railway is important for safety and reliability of train operation, to prevent catastrophic failure, and to reduce maintenance costs. This paper proposes a curvature filtering improved crack detection method in concrete slabs of high-speed railway via graph-based anomalies calculation. Firstly, large curvature information contained in the images is extracted for the crack identification based on an improved curvature filtering method. Secondly, a graph-based model is developed for the image sub-blocks anomalies calculation where the baseline of the sub-blocks is acquired by crack-free samples. Once the anomaly is large than the acquired baseline, the sub-block is considered as crack-contained block. The experimental results indicate that the proposed method performs better than convolutional neural network method even under different curvature structures and illumination conditions. This work therefore provides a useful tool for concrete slabs crack detection and is broadly applicable to variety of infrastructure systems.

• 전기학회논문지
• /
• 제60권6호
• /
• pp.1146-1151
• /
• 2011

There are two methods for train control in information transmission by using track circuit system and installing wayside transmitter. Information signal is transmitted to the on-board antenna by using rails. Continuous information about train intervals, speed and route is received by on-board antenna in AF track circuit system. The information signal is included with carrier wave and received by magnetic coupling in the on-board antenna. Therefore, it is important to define standard current level in the AF track circuit system. When current flowed to rails is low, magnetic sensors are not operated by decreasing magnetic field intensity. Hence, SNR is decreased because electric field intensity is decreased. When the SNR is decreased, there is the serious influence of noise upon demodulation. So, the frequency of information signal is not extracted in frequency response. Thus, it is possible to happen to train accident and delay as the information signal is not analyzed in the on-board antenna. In this paper, standard energy density is calculated by using Parseval's theory in UM71c track circuit. Hence, detection time of information signal is presented.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
• /
• 제53권9호
• /
• pp.545-551
• /
• 2004

CBTC(Communication Based Train Control) System can improve train operation efficiency by realizing moving block system which makes a continuous train interval control in accordance with the position and speed of train. Adopting radio transmission to make a continuous detection of train position and transmit the control data from the ground to a train, CBTC needs dedicated train operation and control algorithm which should be quite different from the conventional track-circuit-based train control system. This paper provides a train operation display and control algorithm for CBTC system in making train interval control, train route control and train supervision. Signalling pattern diagram is devised to analyze the train interval control mechanism of moving block system, and interlocking logic is devised to represent the train route control mechanism of moving block system. For train supervision, train occupation status on railway are displayed by using the segment which virtually divide the whole railway. The proposed method has been successfully applied to the development of CBTC system for the standardized AGT(automatic guided transit) which is under construction now in Korea, and also can be applied to any other CBTC system.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
• /
• 제52권6호
• /
• pp.278-285
• /
• 2003

This paper proposes a new position detection method for train speed control using the Phase Difference of Arriving. This method aims to apply to Automated Guide-way Transit systems, to be operated without driver. So it is absolutely required to range, calculate and decide a train position precisely. This system consists of Vehicle Radio Set(VRS) and Wayside Radio Set(WRS). The VRS transmits a wireless signal to the WRS and the controller calculate a straight line and curve line with Phase Difference of Arriving(PDOA) and an exact position using track date-base is calculated at next step.

• 한국통신학회논문지
• /
• 제42권5호
• /
• pp.1110-1116
• /
• 2017

동작 특성에 따라 궤도회로 장치는 신호기 장치, 선로전환기 및 기타 안전과 관련된 장치의 직접 또는 간접 제어를 위해 설치되며, 주로 열차의 검지, 지상에서 차상으로 제어정보 전송, 궤도 깨짐 검지 및 귀선 전류 전송에 사용된다. 특히 귀선 전류는 신호시스템, 전력시스템 및 전차선 및 궤도회로장치와 관련이 있다. 신호시스템에서 가장 중요한 구성 요소 중 하나인 귀선 전류는 선로변 유지보수자의 안전 및 전철화에 따른 철도 관련 전기시스템의 보호를 위해 적합하게 처리되어야 한다. 따라서, 과전류 상태로 인한 귀선 전류 불평형과 시스템 유도 장애 및 고장을 방지하기 위해서는 귀선 전류의 정확한 분석이 필요하다. 또한, 귀선전류 고조파에 의해 오동작이 발생하면 열차 운행 중단 등의 문제가 발생될 수 있다. 본 논문에서는 이러한 귀선 전류 측정 및 분석 방법을 제시하고 고속열차 운행에 따른 호남고속철도 노선에서의 귀선전류 고조파 시험 결과를 제시하고 있다.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2011년도 춘계학술대회 논문집
• /
• pp.343-349
• /
• 2011

Now, for the continuous location detection of train, the method that the moving distance of a vehicle is detected using an wheel sensor(odometer) mounted within a train, is generally used. It has a problem that the positioning errors of a train can be accumulated as the moving distance increases. To solve this problem, it is required to apply a variety of positioning sensors and to integrate with sensor data. In this paper, we develop the train-borne positioning system applicable to the conventional railway and high-speed railway, and verify the performance of the train-borne positioning system through a vehicle test.