• 정보보호학회논문지
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• 제25권1호
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• pp.225-235
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• 2015

최근 정보보호인증 및 보안감사의 감독과 절차가 강화되고 있지만 내부자에 의한 정보유출 및 보안사고는 지속적으로 늘어나고 있다. 2011 Cyber Security Watch Survey에 의하면 2010년 한 해 동안 발생한 보안사고 중 21%가 내부자에 의해 발생한 것으로 조사되었다. 기업들은 대외서비스와 달리 내부시스템 보안사고의 경우 즉각적으로 인지하지 못하거나 발생 시 비용증가, 신용도하락 등의 이유로 외부에 공시하지 않고 일시적 미봉책으로 해결하는 경우가 많았다. 본 논문은 시스템 접근관리에 대한 문제점을 실증적으로 연구하였으며, 타 시스템 또는 사업장에서 활용이 가능한 표준 프로세스를 제시하였다. 이를 통해 기업들이 쉽고 체계적으로 시스템 접근관리에 대한 문제점을 조사하고 분석하며 개선하는데 도움을 줄 것이다.

• 동력기계공학회지
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• 제15권4호
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• pp.37-41
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• 2011

This paper introduces the special eddy current sensor and its characteristic for bolt hole defect evaluation in gas turbine rotor. In the past, Fluorescent penetration inspection method was used for qualitative defect evaluation in gas turbine rotor bolt hole. This method can defect the bolt hole defect but can not evaluate the defect size. Nowadays, eddy current method is used quantitative defect evaluation due to advanced sensor design technology. And eddy current method is more time and cost saving than the old method. We developed bolt shape eddy current sensor for the rotor bolt hole defect detection and evaluation. The eddy current sensor moves to the bolt hole guided by screw nut and detects the defect on the bolt hole. The bolt hole mock-up and artificial defects were made and used for the signal detection & resolution analysis of eddy current sensor. The results show that signal detection capability is enough to detect 0.2 mm depth defect. And the resolution capability is enough to differentiate 02, 0.5, 1.0 and 2.0 mm depth defect.

• 한국정밀공학회지
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• 제20권11호
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• pp.134-141
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• 2003

An industrial product is designed and fabricated, followed by the inspection process in order to check whether it is dimensionally tolerable or not. The machining process produces a part such as a mold or die, in which the three-dimensional coordinate might be measured by a CMM (Coordinate Measuring Machine) for assessment of its dimension. It is not ignorable, however, that a CMM measurement requires a lot of operating time and cost, which has led to many studies on the OMM system. The OMM system can be categorized into contact and non-contact types, and each of which has its own strengths and weaknesses. Non-contacting types generally utilize structured lights, sounds or magnetic fields. Though they show rather poor performance in positional accuracy, the measuring speed is faster than the contacting probes. This paper presents the development of an OMM system based on a non-contacting laser displacement sensing apparatus and CAD model. The system is composed of software modules of center-aligning and measuring, which has been operated and verified on a NC machining center on a shop floor.

• 산업공학
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• 제10권1호
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• pp.209-222
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• 1997

The paper provides a methodology to obtain the automaticity indicator of a factory and the sequence of enabling technologies of factory automation. The automaticity indicator is the measure of the current automation status of a factory and can be used as a crucial criteria for the future automation schedule and investment. Although most industries have their own computation methods which usually consider the number of workers in the shop floor, this research covers five evaluation items of automation, such as, production facility, material transfer system, inspection and test system, information system, and flexibility. The detailed evaluation models are developed for each item. Automation sequencing prioritizes the enabling technologies of factory automation on the basis of several criteria which consist of two phases. The first phase includes the automation indicator and the second phase includes six sub-criteria such as production rate, quality, number of workers, capital investment, development duration, development difficulty. For this evaluation, AHP(Analytical Hierarchy Process) is introduced to prevent the decision maker's subject intention. As results of the automaticity indicator and automation sequence, the manager can save time and cost in building constructive and transparent automation plans.

• 한국콘텐츠학회논문지
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• 제9권7호
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• pp.121-129
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• 2009

전력검침은 전력 사용요금을 부과하기 위하여 전력사용량을 측정하는 행위를 말하며, 이를 자동화한 시스템을 전력원격검침(AMR: Automatic Meter Reading)이라 한다. 전력원격검침은 검침 인력을 시스템으로 대체해 원가를 줄이고 고객 서비스를 강화할 수 있는 시스템으로 부각되고 있다. 본 논문에서는 기존의 전력원격검침 모델의 대안으로 스마트카드 기반의 전력원격검침 프레임워크 SCEMS를 제안하고 구현하였다. 제안된 SCEMS 프레임워크는 자바카드 기반의 다기능 스마트카드를 사용하며, 스마트카드에 수집된 자료와 가구의 전력사용 패턴을 활용하여 다양한 요금제를 지원하는 등의 고객서비스를 제공한다. 제안된 원격검침 모델 연구는 전력산업의 환경변화에서 초래할 다원화, 이질화, 복합화에 대한 해결방안이 될 수 있을 것으로 보인다.

• Steel and Composite Structures
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• 제12권5호
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• pp.379-393
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• 2012

Many steel bridge infrastructures in the world are getting older, and a large number of these structures are in need of maintenance, rehabilitation or replacement. Most of them are subjected to corrosion due to exposure to aggressive environmental conditions and inadequate maintenance, causing reduction of their carrying capacities. In order to have an adequate bridge management, it is of paramount importance to develop an efficient, accurate and rapid condition assessment method which can be used to make reliable decisions affecting the cost and safety. Therefore, a simple and accurate method of calculating remaining yield and tensile strength by using a concept of representative effective thickness with correlation of initial thickness and maximum corroded depth is proposed in this study, based on the results of many tensile coupon tests of corroded plates obtained from a steel plate girder with severe corrosion, used for about 100 years. Furthermore, a strength reduction diagram which will be very useful for bridge inspection engineers to make rational decisions about the maintenance management of aged steel bridge infrastructures is presented.

• Structural Engineering and Mechanics
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• 제28권5호
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• pp.525-548
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• 2008

This article deals the theory for solving an inverse problem of plate structures using the frequency-domain information instead of classical time-domain delays or free vibration eigenmodes or eigenvalues. A reduced set of output parameters characterizing the defect is used as a regularization technique to drastically overcome noise problems that appear in imaging techniques. A deconvolution scheme from an undamaged specimen overrides uncertainties about the input signal and other coherent noises. This approach provides the advantage that it is not necessary to visually identify the portion of the signal that contains the information about the defect. The theoretical model for Quantitative nondestructive evaluation, the relationship between the real and ideal models, the finite element method (FEM) for the forward problem, and inverse procedure for detecting the defects are developed. The theoretical formulation is experimentally verified using dynamic responses of a steel plate under impact loading at several points. The signal synthesized by FEM, the residual, and its components are analyzed for different choices of time window. The noise effects are taken into account in the inversion strategy by designing a filter for the cost functional to be minimized. The technique is focused toward a exible and rapid inspection of large areas, by recovering the position of the defect by means of a single accelerometer, overriding experimental calibration, and using a reduced number of impact events.

• 한국압력기기공학회 논문집
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• 제16권1호
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• pp.117-124
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• 2020

3D printing is a technology that has significantly grown in recent years, particularly in the aerospace, defense, and medical sectors where it offers significant potential cost savings and reduction of the supply chain by allowing parts to be manufactured on-site rather than at a distance supplier. In nuclear industry, 3D printing technology should be applied according to the manufacturing trend change. For the application of 3D printing technology to the nuclear power plant, several problems, including the absence of code & standards of materials, processes and testing & inspection methods etc, should be solved. Preemptively, the improvement of reliability of 3D printing technology, including mechanical properties, structural performance, service performance and aging degradation of 3D printed parts should be supported. These results can be achieved by collaboration of many organizations such as institute, 3D printer manufacturer, metal powder supplier, nuclear part manufacturer, standard developing organization, and nuclear utility.

• 한국멀티미디어학회논문지
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• 제11권10호
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• pp.1366-1375
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• 2008

계측기 장비들을 검증하기 위해서는 원기를 보유하고 있는 인증기관에 의뢰하여 장비의 이상유무를 검증 받게 된다. 디지털 계측기 같은 고가의 장비를 보유하고 있는 기업에게 이런 검증과정은 시간과 비용을 가져온다. 본 연구에서 제안한 '계측기-스마트 네트워크 카드 모델'은 디지털 계측기에 스마트 네트워크 모듈을 탑재하는데, 이 카드는 기존의 웹 어댑터에 원격지에서 프로그램을 적재, 삭제, 실행이 가능하도록 스마트 기능을 추가하여 원격검증 및 제어가 가능하다. 제안한 모델은 다수의 프로그램이 적재 가능하여 응용가치 또한 높으며, 국내외로 판매한 고가의 디지털 계측기 하나하나를 인터넷을 이용하여 원격제어가 가능하게 하고, 원격으로 검증 조건을 교체할 수 있도록 함으로써, 장비의 질과 경쟁력을 높일 수 있다.

• 한국통신학회논문지
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• 제35권5B호
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• pp.824-832
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• 2010

구조물의 관리에서 전문 관리 인력이 직접 조사하는 방식은 예산이나 검사 방법 및 주기에 따라 그 효과가 달라진다. 따라서 효과적이며 자동화된 구조물의 유지관리 방안이 필요하다. 교량 관리에서 자동화된 관리 방안으로는 몇몇 교량에 유선통신 방식을 이용한 상시 감시 시스템을 구축, 운영하고 있으나 교량 통합관리 시스템으로서의 성능은 초보적인 수준에 머물고 있다. 본 논문에서는 센서 네트워크를 적용한 교량의 통합관제 시스템을 구현한다. 교량에 설치된 센서를 무선망으로 구성하고 수집된 정보의 상시 모니터링을 위해 교량 관리자를 위한 기능과 관리시스템 관리용 기능, 그리고 비전문가용 웹 기반 모니터링 시스템을 구축하였다. 본 연구의 결과는 실험대상 교량에 적용하여 그 효과를 분석하고 있다.