• Bulletin of the Korean Chemical Society
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• 제10권4호
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• pp.372-374
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• 1989

The new viscosity theory is applied to the abnormal behavior of the viscosity near the critical point. This theory suggests that the viscosity is equal to the product of the absolute pressure(kinetic pressure + internal pressure) and the collision time. We can find this abnormal behavior to be due to the large collision time near the critical point. The agreements between theoriticals and experimentals of the critical enhancement are satisfactory.

• 한국구조물진단유지관리공학회 논문집
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• 제19권2호
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• pp.92-98
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• 2015

최근의 건축물은 복합적인 기능과 형태를 보이고 있으며, 크기가 거대해짐에 따라 구조물 건전성 감시 (Structural Health Monitoring)기술의 수요 또한 증가하고 있다. 구조물마다 고유한 동특성을 가지고 있으며, 다양한 외력의 영향을 받기 때문에 구조물의 건전성을 평가하는 다양한 방법들이 연구되고 있다. 이상거동 시점이란 구조물이 비정상적 (Abnormal)으로 진동하는 시점으로 손상을 명확히 검출하기 위해서는 이상거동의 시점을 기준으로 전과 후를 비교하여야 한다. 즉, 이상거동은 구조물 손상의 이상 징후이며, 정확한 이상거동 시점의 추정은 구조물의 안전과 직결될 수 있다. 이상 거동은 손상을 유발하고 이는 곧 막대한 경제적 피해 및 심각한 인명 피해로 이어지므로 본 연구에서는 시간-주파수 신호분석 기법인 힐버트-황 변환을 이용한 이상거동 시점 추정 기법을 제안하고 진동대를 이용한 모형실험을 통해 제안한 알고리즘의 검증을 수행하였다.

• 한국통신학회논문지
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• 제30권1C호
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• pp.107-115
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• 2005

본 논문에서는 네트워크의 생존성을 보장하고 신뢰성 높은 인터넷 서비스를 제공하기 위한 차세대 보안기술로서 인터넷의 액세스점에 위치하는 이상 트래픽 제어기(ATC, Abnormal Traffic Controller)를 제안한다. ATC의 주요 개념은 이상 트래픽 감지와 트래픽 제어기술에 있는데, 네트워크에서 에러의 요인이 계속 존재하거나 반복되는 경우 이상 트래픽 제어를 통해 서비스 완료성을 가능한 보장하는 것을 그 목적으로 한다. 분석결과, 이상 트래픽 중 유효 트래픽의 비율이 $30{\%}$를 초과하는 경우에는 이상 트래픽에 대한 제어정책을 사용하는 ATC는 기존의 네트워크 노드 뿐만 아니라 차단정책을 사용하는 ATC보다 우수한 성능을 나타내었다. 과다 트래픽의 알려지지 않은 공격이 발생하는 경우, 높은 오탐지율로 인해 기존의 네트워크 IDS로는 한계가 있는데, 이러한 환경에서 ATC는 네트워크 노드를 도와서 이상 트래픽을 제어하는데 주요한 역할을 수행하게 된다.

• 한국통신학회논문지
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• 제30권4C호
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• pp.296-304
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• 2005

본 논문에서는 네트워크의 생존성을 보장하고 신뢰성 높은 인터넷 서비스를 제공하기 위해 인터넷의 액세스점에 위치하는 예측기반 이상 트래픽 제어기(ATCoP, Abnormal Traffic Controller based on Prediction)를 제안한다. ATCoP는 네트워크로 유입되는 트래픽 중 이상 트래픽을 제어하는 방법으로서, 알려지지 않은 공격에 의해 트래픽이 과다하게 발생하는 경우에, 정상 트래픽에 우선권을 주기 위해 서비스 성공률을 측정하고 그 결과를 기준으로 정상 트래픽용 예약 채널의 수를 결정하여 정상 트래픽의 서비스 수준을 보장함으로써 서비스 생존성을 높히는 방법이다. 만일 예약 채널의 수가 증가하면, 이상트래픽에 할당되는 채널의 수가 감소하게 되어 이상트래픽의 서비스 생존율은 감소하게 된다. 분석결과, 제안 방식은 입력트래픽의 특정 범위에서는 정상트래픽의 블록킹율을 일정 수준으로 유지시켜주는 효과가 있음을 알 수 있었다.

• Journal of Advanced Marine Engineering and Technology
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• 제30권2호
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• pp.247-252
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• 2006

Almost ship monitoring systems are event driven alarm system which warn only when the measurement value is over or under set point. These kinds of system cannot warn until signal is growing to abnormal state that the signal is over or under the set point. therefore cannot play a role for preventive maintenance system. This paper proposes fault diagnosis method which is able to diagnose and forecast the fault from present operating condition by analyzing monitored signals with present ship monitoring system without any additional sensors. By analyzing the data with high correlation coefficient(CC), correlation level of interactive data can be defined. Knowledge base of abnormal detection can be built by referring level of CC(Fault Detection CC. FDCC) to detect abnormal data among monitored data from monitoring system and knowledge base of diagnosis built by referring CC among interactive data for related machine each other to diagnose fault part.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2005년도 전기학술대회논문집
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• pp.281-286
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• 2005

Almost ship monitoring systems are event driven alarm system which warn only when the measurement value is over or under set point. These kinds of system cannot warn while signal is growing to abnormal state until the signal is over or under the set point and cannot play a role for preventive maintenance system. This paper proposes fault diagnosis method which is able to diagnose and forecast the fault from present operating condition by analyzing monitored signals with present ship monitoring system without additional sensors. By analyzing this data having high correlation coefficient(CC), correlation level of interactive data can be understood. Knowledge base of abnormal detection can be built by referring level of CC(Fault Detection CC, FDCC) to detect abnormal data among monitored data from monitoring system and knowledge base of diagnosis built by referring CC among interactive data for related machine each other to diagnose fault part.

• 한국기계가공학회지
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• 제14권1호
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• pp.51-56
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• 2015

This paper presents an investigation of abnormal wear of a contact jig between a nail and a nail fixture in electric resistance welding. To perform an analysis on the abnormal wear phenomenon, several methods are provided. Based on the theory of electric resistance welding, are analyzed. Using microscopic analysis, surface craters are observed. In the measurement of the electric current flow in the nail fixture, the current flow distribution is measured. From several analyses, the cause of abnormal wear in the contact jig is measured using the electric discharge of high current density at the inflow point of the electric supply to the nail fixture. An alternative shape for normal wear is proposed.

• 대한원격탐사학회지
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• 제38권4호
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• pp.355-364
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• 2022

In this study a tendency of abnormal sea surface temperature (SST) occurrence in the seas around South Korea is analyzed from daily SST data from satellite and 14 buoys from August 2020 to July 2021. As thresholds 28℃ and 4℃ are used to determine marine heatwaves(MHWs) and abnormal low water temperature (ALWT), respectively, because those values are adopted by the National Institute of Fisheries Science for the breaking news of abnormal temperature. In order to calculate frequency of abnormal SST occurrence spatially by using satellite SST, research area was divided into six areas of coast and three open seas. ALWT dominantly appeared over a wide area (7,745 km²) in Gyeonggi Bay for total 94 days and it was also confirmed from buoy temperature showing an occurrence number of 47 days. MHWs tended to be high in frequency in the coastal areas of Chungcheongdo and Jeollabukdo and the south coastal areas while in case of buoy temperature Jupo was the place of high frequency (32 days). This difference was supposed to be due to the low accuracy of satellite SST at the coasts. MHWs are also dominant in offshore waters around Korean Peninsula. Although detecting abnormal SST by using satellite SST has advantage of understanding occurrence from a spatial point of view, we also need to perform detection using buoys to increase detection accuracy along the coast.

• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2003년도 Proceedings of the international symposium on the fusion technology
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• pp.437-440
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• 2003

As we know, roof is composed of heterogeneous rock. When roof fractures, a large amount of energy would be released in the form of seismic wave. How to identify the abnormal signal of seismic wave is a much difficult problem, there are many methods used usually, such as Fourier Transformation, filter technique etc., but abnormal signal can't be recognized accurately. In this paper, multi-resolution wavelet technique is used to identify the first and second variation point, based on the Lipschitz $\alpha$. A living example analysis shows, multi-resolution wavelet technique can identify the abnormal signal of seismic wave effectively in different scale, and the omen of roof fall can be grasped in order to forecast the roof fall accurately. It provides a new idea for the predication of catastrophe on rock mechanics and engineering.

• 대한한의진단학회지
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• 제17권3호
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• pp.233-240
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• 2013

Objectives The objective and universal grading system for the facial nerve palsy is needed to the objectification of treatment in Oriental medicine. In this study, the facial nerve palsy grading was developed with combination of image processing technique and Nottingham scale. Methods The developed system is composed of measurement part, image processing part, facial nerve palsy evaluation part, and display part. With the video data recorded by webcam at measurement part, the positions of marker were measured at image processing part. In evaluation part, Nottingham scales were calculated in four different facial expressions with measured marker position. The video of facial movement, time history of marker position, and Nottingham scale were displayed in display part. Results & Conclusion The developed system was applied to a normal subject and a abnormal subject with facial nerve palsy. The left-right difference of Nottingham scores was large in the abnormal compared with the normal. In normal case, the change of the length between supraorbital point and infraorbital point was larger than that of the length between lateral canthus and angle of mouth. The abnormal case showed an opposite result. The developed system showed the possibilities of the objective and universal grading system for the facial nerve palsy.