• International Journal of Computer Science & Network Security
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• 제21권6호
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• pp.1-6
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• 2021

Recently, pre-trained convolutional neural network CNNs have been widely used and applied for medical image classification. These models can utilised in three different ways, for feature extraction, to use the architecture of the pre-trained model and to train some layers while freezing others. In this study, the ResNet18 pre-trained CNNs model is used for feature extraction, followed by the support vector machine for multiple classes to classify medical images from multi-classes, which is used as the main classifier. Our proposed classification method was implemented on Kvasir and PH2 medical image datasets. The overall accuracy was 93.38% and 91.67% for Kvasir and PH2 datasets, respectively. The classification results and performance of our proposed method outperformed some of the related similar methods in this area of study.

• 한국방재학회 논문집
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• 제6권4호통권23호
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• pp.7-14
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• 2006

기존선에 투입되는 틸팅차량은 기존 차량과는 다른 운행 메커니즘을 가지고 있으므로 안정성을 확보하기 위해서는 궤도부담력 및 주행안정성 검토와 노반의 안정성 검토가 필요하다. 본 연구에서는 레일 이음매 궤도에 대하여 틸팅차량이 궤도부담력과 주행안정성 검토에서 산정된 허용속도로 운행될 경우 발생하는 노반의 침하량을 수치해석을 통해 검토하였다. 틸팅차량 하중에 의해 발생되는 노반의 침하량과 허용침하량을 비교하여 노반의 안정성을 검토하였으며, 허용침하량과 틸팅차량 하중에 의해 발생하는 침하량의 비를 안전율이라 정의하여 안전율을 검토하였다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.1874-1880
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• 2011

In this paper, sensitivity analysis of the pantograph for the high-speed Train was conducted using finite element analysis method. Dynamic interaction of catenary-pantograph model was simulated by using a commercial finite element analysis software, SAMCEF. Pantograph was assumed to be three degree of freedom mass-spring-damper model and the pre-sag of the contact and messenger wire was implemented due to gravity. The span data of the actual high-speed line and specification of pantograph for high-speed train was applied in the analysis model, respectively. The reliability of the simulation model is verified by comparing the contact force results of simulation and test. Through the simulation, mean contact force and its deviation was evaluated and then sensitivity of the pantograph was analyzed.

• 한국자동차공학회논문집
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• 제4권2호
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• pp.90-105
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• 1996

A real tine simulator of running power train for a construction vehicle was developed. The simulator mainly consists of following two parts; (1) running power train part and (2) running load generation part. An optimal servo control algorithm was adopted for designing the multi-variable digital control system of the simulator. By experiments investigating response characteristics under step-wise variation or pre-determined scenario of target vehicle velocity and target load torque, it was verified that the simulator could reproduce physical situations at and actual vehicle with excellent similarity.

• 대한전기학회논문지:시스템및제어부문D
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• 제53권10호
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• pp.720-726
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• 2004

The data transmission over MVB(Multifunction Vehicle Bus) of TCN(Train Communication Network) is divided into the periodic transmission phase and the sporadic transmission phase. TCN standard recommends the event-polling method as the message transfer in the sporadic phase. However, since the event-polling method does not use pre-scheduling to the priority of the messages, it is inefficient for the real-time systems. To schedule message transmission, a master node should know the priority of message to be transmitted by a slave node prior to the sporadic phase, but the existing TCN standard does not support any protocol for this. This paper proposes the slave frame bit-stuffing algorithm, with which a master node gets the necessary information for scheduling and includes the simulation results of the event-polling method and the proposed algorithm.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2009년도 춘계학술대회 논문집
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• pp.291-295
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• 2009

We did the blooth module test as a pre-test of wireless sensor monitoring system, which for the improving of on-condition maintenance reliability, on the train. In this test, we examined the communication environment of wireless sensor monitoring system by the acceleration date and frequency date in the real train structure during the operation. Also based on this results, we did the experimental verification of the sensor power system which use piezoelectric energy conversion technology by the theoretical modeling for the applying on the train on-condition maintenance.

• International Journal of Railway
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• 제3권3호
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• pp.90-94
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• 2010

In this paper, driving functions of the Korea High-speed Trains were decomposed based on systems engineering architecture. In order to analyze the driving function, various systems engineering tools and methods were used. Moreover, interfaces of decomposed driving functions were analyzed to figure out purposes of the driving functions. Through activity modeling of driving function of the Korea High-Speed Trains, main functions were derived when starting, speeding and stopping. When the high speed train is speeding, pre-departure checks and wheel slide prevention are essential driving activities for the safety and when the high speed train runs high speed, maintaining driving stability by monitoring bogie hunting and monitoring drivers' safe operation by vigilance systems is important. Furthermore, when the train is braking, the driver should checks brake and suspensions as safety actions.

• 한국산학기술학회논문지
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• 제16권9호
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• pp.6274-6281
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• 2015

무선통신기반 열차제어시스템은 차상과 지상과의 양방향 무선통신을 기반으로 실시간 열차간격제어가 가능하므로 운전시격 단축 효과가 있으며 궤도회로를 사용하지 않기 때문에 설비투자를 절감 할 수 있다. 무선통신기반 열차제어시스템에서 가장 중요한 부분인 자동열차방호(ATP: Automatic Train Protection)는 실시간 열차위치 추적을 기반으로 선행열차와 후행열차간의 안전한 간격제어를 수행한다. 본 논문은 도시철도용 무선통신기반 열차제어시스템의 열차간격제어를 위한 전체적인 ATP 열차간격제어 알고리즘과 ATP의 처리속도 향상을 위해 전처리 기반 속도프로파일 계산 알고리즘을 제안한다. 제안된 속도프로파일 계산 알고리즘은 사전에 선로와 열차의 영구속도제한에 해당하는 프로파일을 미리 계산하여 가장제한적인 속도프로파일로 활용한다. 만약 운행 중 특정 노선 구간에 임시속도제한이 발생하는 경우 미리 계산된 영구속도프로파일에 임시속도제한을 반영하여 해당 구간의 속도프로파일을 업데이트함으로써 계산효율을 높일 수 있다. 제안된 속도프로파일 계산 알고리즘의 성능을 평가하기 위해 시간복잡도 O-notation으로 분석하였으며 그 결과 기존에 비해 시간 복잡도를 개선할 수 있음을 확인하였다. 또한 ATP 열차간격제어 검증을 위해 열차간격제어 시뮬레이터를 제작하였으며 실험결과를 통해 다양한 운영상황에서 안전한 열차간격제어가 이루어지고 있음을 확인하였다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2009년도 춘계학술대회 논문집
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• pp.972-977
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• 2009

For the improvement of a train speed in the conventional line from overhead system point of view, it is necessary to approach not only in the aspect of the increasement of tension for catenary but the application of a pre-sag. A certain tension acting on a dropper is removed when it is slack by the pantograph passing. Right after the pantograph passes, the dynamic force caused by the mass of contact wire acts on the dropper. If the pre-sag is applied to the catenary, the static force on the dropper is increased. For the assurance of the safety for the dropper, it is necessary to predict the dynamic force. The purpose of this study is to predict and analyze the force on the dropper according to the applied pre-sag.

• 한국지반공학회논문집
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• 제23권6호
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• pp.115-126
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• 2007

틸팅차량은 기존의 하부구조를 최대한 활용하여 효과적으로 고속서비스를 제공할 수 있다는 점에서 세계 여러 철도 운영자들의 높은 호응을 받고 있지만 기존에 운행 중인 차량과는 차량의 성능뿐 아니라 곡선부의 주행속도와 통과 메커니즘 등이 다르기 때문에 운행 및 노반의 안정성 평가가 이루어져야 한다. 본 연구에서는 틸팅차량이 궤도부 담력과 주행안정성 검토에서 산정된 허용속도로 운행할 경우 수치해석을 통하여 침하량과 지지력 측면에서 노반의 거동을 분석하였고 기후변화 및 열차의 반복하중으로 인해 연약해진 노반의 안정성 검토를 수행하였다. 수치해석 결과, 상부노반 및 원지반의 탄성계수가 장대레일의 경우 $2,300t/m^2$ 및 $3,300t/m^2$ 이상, 레일이음매의 경우 $3,800t/m^2$ 및 $4,600t/m^2$ 이상일 때 노반의 침하량은 허용침하량 값을 만족한다.