• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 A
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• pp.470-473
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• 2000

Because of the continuous growth of energy consumption, and also the tendency to site power lines and pipelines along the same routes, the close proximity of high voltage structures and metallic pipelines has become more and more frequent. Moreover, normal steady state and fault currents become higher as electric networks increase in size and power. Therefore, there has been and still is a growing concern (safety of people marking contact with pipeline, risk of damage to the pipeline coating, the metal and equipment connected to pipeline. especially cathodic protection system) about possible hazards resulting from the influence of high voltage power system on metallic structures(gas pipeline, oil pipeline and water pipeline etc.). Therefore, we analyze the interference problems when the gas pipeline is buried with power cable in the same submarine tunnel. This paper present the results of the study about interference mechanism, AC corrosion, limitation of safety voltage and analysis of indiction voltage.

• International Journal of Railway
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• 제9권2호
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• pp.36-40
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• 2016

TETRA communication system is very versatile system which can transmit voice + data and packet data optimized. Direct mode operation permits to connect between mobiles when mobile stain is out of coverage of networks. It can be more secure communication channel for railway signaling systems. Railway signaling systems use many of wayside signal equipment, which require many maintenance efforts and budget. Many railway authorities want to reduce and replace the wayside equipment. Radio based signaling systems are one of candidate for replacing the conventional signaling systems. The radio based signaling systems can replace track circuit and wayside signal. The radio systems permit to connect between control centers and trains. The radio systems have to ensure high quality of the connectivity more or equal to the existed track circuits. We studied the application of TETRA systems for railway radio systems for bridging between train control centers and trains. We provide an operation scenario for radio based train control system to ensure the safety require to the existed trains control system and satisfied the existed operational availability. We showed the data transmission speed, maximum bit error rate, and data coding for the radio-based signal system using TETRA systems.

• Nuclear Engineering and Technology
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• 제46권3호
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• pp.373-380
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• 2014

Safety-related parameters are very important for confirming the status of a nuclear power plant. In particular, the reactor vessel water level has a direct impact on the safety fortress by confirming reactor core cooling. In this study, the reactor vessel water level under the condition of a severe accident, where the water level could not be measured, was predicted using a fuzzy neural network (FNN). The prediction model was developed using training data, and validated using independent test data. The data was generated from simulations of the optimized power reactor 1000 (OPR1000) using MAAP4 code. The informative data for training the FNN model was selected using the subtractive clustering method. The prediction performance of the reactor vessel water level was quite satisfactory, but a few large errors were occasionally observed. To check the effect of instrument errors, the prediction model was verified using data containing artificially added errors. The developed FNN model was sufficiently accurate to be used to predict the reactor vessel water level in severe accident situations where the integrity of the reactor vessel water level sensor is compromised. Furthermore, if the developed FNN model can be optimized using a variety of data, it should be possible to predict the reactor vessel water level precisely.

• 한국통신학회논문지
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• 제30권11B호
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• pp.744-749
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• 2005

본 논문에서는 기존의 QoS 라우팅 알고리즘이 가지고 있는 문제점인 네트워크 상태 정보 오버헤드를 최소화하면서 네트워크 상태의 정확성을 유지하기 위한 예측 기반 QoS 라우팅 기법인 PSS (Prediction Safety-Shortest) 라우팅 알고리즘 모델을 제안하였다. QoS 라우팅의 상태 정보 갱신 주기에 따른 가용 대역폭의 부정확한 정보를 극복하기 위하여 네트워크 상태를 적용할 수 있는 시계열 예측 알고리즘을 적용하였고, 알고리즘의 성능 평가를 위하여 실제 네트워크와 유사한 MCI 네트워크상에서 시뮬레이션 수행하였으며 라우팅 실패율, 라우팅 대역폭 실패율, 그리고 라우팅 부정확율의 비교를 통하여 본 알고리즘의 우수성을 확인하였다.

• 비파괴검사학회지
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• 제35권6호
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• pp.421-428
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• 2015

An important trend in the sustainment of military aircraft is the transition from preventative maintenance to condition based maintenance (CBM). For CBM, it is essential that the actual system condition can be measured and the measured condition can be reliably extrapolated to a convenient moment in the future in order to facilitate the planning process while maintaining flight safety. Much research effort is currently being made for the development of technologies that enable CBM, including structural health monitoring (SHM) systems. Great progress has already been made in sensors, sensor networks, data acquisition, models and algorithms, data fusion/mining techniques, etc. However, the transition of these technologies into service is very slow. This is because business cases are difficult to define and the certification of the SHM systems is very challenging. This paper describes a possibility for fielding a SHM system on legacy military aircraft with a minimum amount of certification issues and with a good prospect of a positive return on investment. For appropriate areas in the airframe the application of SHM will reconcile the fail-safety and slow crack growth damage tolerance approaches that can be used for safeguarding the continuing airworthiness of these areas, combining the benefits of both approaches and eliminating the drawbacks.

• 한국정보통신학회논문지
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• 제9권4호
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• pp.733-738
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• 2005

1992년 새로 도입된 GMDSS(Global Maritime Distress and Safety System: 세계 해상 조난 및 안전 제도)는 기존의 조난통신 제도를 새로운 정보통신기술을 사용하여 획기적으로 개선하였으며 쉽고 자동화된 조난신호발신 체제 및 효율적이고 범세계적인 수색구조 통신망을 구축하였음에도 불구하고 여러 가지 문제점을 나타내고 있다. 협약선과 비협약선의 조난통신 이원화 문제, 다량의 허위 조난신호 발생에 따른 수색구조의 어려움, 운용능력의 저하로 인한 조난통신 대응체제의 부재 둥은 GMDSS 제도의 도입에 따른 조난통신의 대표적인 문제점들이다 본 논문에서는 우리나라의 관점에서 본 GMDSS 조난통신 제도의 문제점 들을 분석하고 이에 대한 개선방안을 제시하고자 한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권9호
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• pp.4183-4204
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• 2018

The existing en-route filtering schemes only consider some simple false data injection attacks, which results in lower safety performance. In this paper, we propose an efficient geographical information-based en-route filtering scheme (EGEFS), in which each forwarding node verifies not only the message authentication codes (MACs), but also the report identifier and the legitimacy and authenticity of locations carried in a data report. Thus, EGEFS can defend against not only the simple false data injection attacks and the replay attack, but also the collusion attack with forged locations proposed in this paper. In addition, we propose a new method for electing the center-of-stimulus (CoS) node, which can ensure that only one detecting node will be elected as the CoS node to generate one data report for an event. The simulation results show that, compared to the existing en-route filtering schemes, EGEFS has higher safety performance, because it can resist more types of false data injection attacks, and it also has higher filtering efficiency and lower energy expenditure.

• 대한안전경영과학회지
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• 제14권3호
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• pp.269-276
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• 2012

플라스틱 사출 제품은 다양한 가전제품과 하이테크 제품에 널리 사용되고 있다. 그러나 현재의 치열한 경쟁적 비즈니스 환경에서 플라스틱 사출 제품 제조업자들은 고객을 만족시키면서 경쟁력을 얻기 위하여 다른 경쟁자들보다 먼저 새로운 제품을 시장에 출시하고 신제품의 개발기간을 줄이기 위한 노력을 할 여유가 부족하다. 따라서 무한경쟁의 시장에서 살아남기 위해서는 제조업자들은 시장 마켓 점유를 빠르게 올리는 것과 동시에 제품의 가격 경쟁력을 가져야 한다. 특징기반 모델의 구조는 현재 연구에서 3D 제작 도구로서 일반적으로 적용되고 있으며 신제품 개발 엔지니어들이 새로운 제품의 개념을 개발하는 데에도 널리 사용되고 있다. 본 연구에서는 특징기반 플라스틱 사출제품을 위한 유전자 알고리즘과 Support Vector Regression (SVR) 기반의 새로운 하이브리드 비용 평가 모델을 제안한다. 제안하는 하이브리드 모델은 기존의 플라스틱 사출제품의 비용평가절차와 계산을 위해 필요로 하는 변수들을 극적으로 간단하게 하고 줄일 수 있다. 사례연구에서는 제안하는 하이브리드 모델과 기존의 multilayer perceptron networks (MLP) 및 pure SVR과의 비교분석을 통하여 제안모델이 플라스틱 사출 제품의 개발단계에서의 비용평가문제를 해결하는데 효율성과 효과성이 있음을 입증한다.

• Journal of Electrical Engineering and Technology
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• 제13권5호
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• pp.2099-2106
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• 2018

This study presents a novel approach of discriminative feature vectors based on manifold learning using nonlinear dimension reduction (DR) technique to improve loss function, and combine with the Adversarial examples to regularize the object function for image classification. The traditional convolutional neural networks (CNN) with many new regularization approach has been successfully used for image classification tasks, and it achieved good results, hence it costs a lot of Calculated spacing and timing. Significantly, distrinct from traditional CNN, we discriminate the feature vectors for objects without empirically-tuned parameter, these Discriminative features intend to remain the lower-dimensional relationship corresponding high-dimension manifold after projecting the image feature vectors from high-dimension to lower-dimension, and we optimize the constrains of the preserving local features based on manifold, which narrow the mapped feature information from the same class and push different class away. Using Adversarial examples, improved loss function with additional regularization term intends to boost the Robustness and generalization of neural network. experimental results indicate that the approach based on discriminative feature of manifold learning is not only valid, but also more efficient in image classification tasks. Furthermore, the proposed approach achieves competitive classification performances for three benchmark datasets : MNIST, CIFAR-10, SVHN.

• 한국안전학회지
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• 제17권4호
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• pp.196-201
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• 2002

웹기반 예지보전 (Predictive Maintenance)은 가상 디바이스 네트워크를 필요로 한다. 가상 디바이스 네트워크는 반드시 분산형 감시 및 제어 네트워크를 통해서만 구현될 수 있다. 일반적으로 분산형 감시 및 제어 네트워크를 인터넷 상에서 구현하려면 TCP/IP와 필드버스 프로토콜의 통합이 필요하다. 이 경우, 예지보전의 성능을 극대화하기 위해서는 기기간의 통신 호환성이 절대적으로 필요하다. 본 논문에서는 가상 디바이스 네트워크의 통신 특성을 분석하고 이를 토대로 분산형 감시 및 제어 네트워크를 활용한 웹기반 예지보전의 기본 틀을 제시한다.