• 융합보안논문지
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• 제21권1호
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• pp.93-100
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• 2021

지능형 사이버 공격으로 인한 피해는 시스템 운영 중단과 정보 유출뿐만 아니라 엄청난 규모의 경제적 손실을 동반한다. 최근 사이버 공격은 공격 목표가 뚜렷하며, 고도화된 공격 도구와 기법을 활용하여 정확하게 공격 대상으로 침투한다. 이러한 지능적인 사이버 공격으로 인한 피해를 최소화하기 위해서는 사이버 공격이 공격 대상의 핵심 시스템까지 침입하지 못하도록 공격 초기 또는 과정에서 차단해야 한다. 최근에는 빅데이터나 인공지능 기술을 활용하여 사이버 공격 경로를 예측하고 위험 수준을 분석하는 보안 기술들이 연구되고 있다. 본 논문에서는 자동화 사이버 공격 경로 예측 시스템 개발을 위한 기초 메커니즘으로 공격 트리와 RFI 기법을 활용한 사이버 공격 경로 분석 방법을 제안한다. 공격 트리를 활용하여 공격 경로를 가시화하고 각 공격 단계에서 RFI 기법을 이용하여 다음 단계로 이동할 수 있는 경로를 판단한다. 향후에 제안한 방법을 기반으로 빅데이터와 딥러닝 기술을 활용한 자동화된 사이버 공격 경로 예측 시스템의 메커니즘으로 활용할 수 있다.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2005년도 학술발표회 논문집
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• pp.331-342
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• 2005

This paper presents a non-destructive evaluation (NDE) technique for detecting damages on a jointed steel plate on the basis of the time of flight and wavelet coefficient, obtained from wavelet transforms of Lamb wave signals. Support vector machines (SVMs), which is a tool for pattern classification problems, was applied to the damage estimation. Two kinds of damages were artificially introduced by loosening bolts located in the path of the Lamb waves and those out of the path. The damage cases were used for the establishment of the optimal decision boundaries which divide each damage class's region from the intact class. In this study, the applicability of the SVMs was investigated for the damages in and out of the Lamb wave path. It has been found that the present methods are very efficient in detecting the damages simulated by loose bolts on the jointed steel plate.

• Earthquakes and Structures
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• 제26권2호
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• pp.87-96
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• 2024

This paper proposes a logistic multinomial regression approach to model the spatial cross-correlation of damage probabilities among different damage states in an expanded transportation network. Utilizing Bayesian theory and the multinomial logistic model, we analyze the damage states and probabilities of bridges while incorporating damage correlation. This correlation is considered both between bridges in a network and within each bridge's damage states. The correlation model of damage probabilities is applied to the seismic assessment of a portion of Tehran's transportation network, encompassing 26 bridges. Additionally, we introduce extra daily traffic time (EDTT) as an operational parameter of the transportation network and employ the shortest path algorithm to determine the path between two nodes. Our results demonstrate that incorporating the correlation of damage probabilities reduces the travel time of the selected network. The average decrease in travel time for the correlated case compared to the uncorrelated case, using two selected EDTT models, is 53% and 71%, respectively.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2003년도 가을 학술발표회 논문집
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• pp.501-504
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• 2003

The purpose of this work is to introduce some fundamental stereological concepts to quantify damage parameters using X-ray CT(Computed Tomography) in the scope of CDM(Continuum Damage Mechanics). X-ray CT is a completely nondestructive technique for visualizing features in the interior of opaque solid objects, and for obtaining digital information on their 3D geometries and properties. Many researchers have introduced lots of damage parameters to model the mechanical behavior of deteriorated materials. Those damage parameters can be represented in many forms such as specific void or crack surfaces, the spacing between cracks, the specific damaged surface area, the specific damaged surface area tensor, the mean solid path among the damaged surfaces and the mean solid path tensor. Despite of many accomplishments in CDM since there is no the systematic experiment, it have limitations in application. In this situation, X-ray computed tomography is highlited by many researchers and applied in a wide range of materials including rock, bone, ceramic, metal, soft tissue and concrete.

• 전기학회논문지
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• 제65권10호
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• pp.1786-1791
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• 2016

The damage has occurred inside the semiconductor pattern When using conventional wet station for semiconductor. It was used for electrolytic ion water generator in order to prevent damage to the semiconductor pattern. It was designed and developed a flow path electrode and the mesh electrode to check the efficiency of the electrode. And It confirmed the expected results through the simulation of the flow path. and ORP were measured in accordance with the current and voltage of mesh electrode and flow paht electrodes. Flow path electrode 22A is 3V, up to pH 9.8, the value of ORP-558mV was measured and the mesh electrode was measured up to pH 9.8, ORP -350mV.

• Earthquakes and Structures
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• 제15권5호
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• pp.529-540
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• 2018

The influences of initial damage paths and aftershock (AS) spectral shape on the assessment of AS collapse fragility are investigated. To do this, a four-story ductile reinforced concrete (RC) frame structure is employed as the study case. The far-field earthquake records recommended by FEMA P695 are used as AS ground motions. The AS incremental dynamic analyses are performed for the damaged structure. To examine the effect of initial damage paths, a total of six kinds of initial damage paths are adopted to simulate different initial damage states of the structure by pushover analysis and dynamic analysis. For the pushover-based initial damage paths, the structure is "pushed" using either uniform or triangle lateral load pattern to a specified damage state quantified by the maximum inter-story drift ratio. Among the dynamic initial damage paths, one single mainshock ground motion or a suite of mainshock ground motions are used in the incremental dynamic analyses to generate a specified initial damage state to the structure. The results show that the structure collapse capacity is reduced as the increase of initial damage, and the initial damage paths show a significant effect on the calculated collapse capacities of the damaged structure (especially at severe damage states). To account for the effect of AS spectral shape, the AS collapse fragility can be adjusted at different target values of ${\varepsilon}$ by using the linear correlation model between the collapse capacity (in term of spectral intensity) and the AS ${\varepsilon}$ values, and coefficients of this linear model is found to be associated with the initial damage states.

• 한국건축시공학회지
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• 제16권5호
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• pp.437-445
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• 2016

태풍은 인류에 큰 피해를 주는 재난재해로 몇몇 선진국에서는 태풍으로 인한 건축물 피해액 사전예측 모델에 관한 연구가 진행되고 있다. 국내에서도 해외 연구를 토대로 국내에 적용시키는 연구가 진행되었지만, 태풍의 특성이나 크기 등이 차이가 나므로 국내에 적합한 모델이 필요한 실정이다. 또한, 국내의 연구는 태풍의 특성, 지역적 특성만을 고려하여 진행 하였으나, 태풍은 복합재해로서 태풍의 특성, 지리적 특성만이 아닌 태풍의 진로, 건설환경, 등 다양한 요인을 고려하여야한다. 이에 본 연구에서는 국내에 영향을 미친 태풍을 7가지 타입으로 분류하여 건물피해액 영향인자를 도출하고, 회귀분석을 실시하여 태풍 타입별 건물피해율 예측모델을 개발 목적으로 한다. 이는 선진국의 자연재해 예측모델들과 같이 국내의 상황에 맞는 태풍에 따른 피해를 예측하기 위한 모델 개발을 위한 자료로 활용 될 것이다.

• Structural Engineering and Mechanics
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• 제81권6호
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• pp.665-675
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• 2022

The safety problems of giant hydraulic structures such as dams caused by terrorist attacks, earthquakes, and wars often have an important impact on a country's economy and people's livelihood. For the national defense department, timely and effective assessment of damage to or impending damage to dams and other structures is an important issue related to the safety of people's lives and property. In the field of damage assessment and vulnerability analysis, it is usually necessary to give the damage assessment results within a few minutes to determine the physical damage (crack length, crater size, etc.) and functional damage (decreased power generation capacity, dam stability descent, etc.), so that other defense and security departments can take corresponding measures to control potential other hazards. Although traditional numerical calculation methods can accurately calculate the crack length and crater size under certain combat conditions, it usually takes a long time and is not suitable for rapid damage assessment. In order to solve similar problems, this article combines simulation calculation methods with machine learning technology interdisciplinary. First, the common concrete gravity dam shape was selected as the simulation calculation object, and XFEM (Extended Finite Element Method) was used to simulate and calculate 19 cracks with different initial positions. Then, an LSTM (Long-Short Term Memory) machine learning model was established. 15 crack paths were selected as the training set and others were set for test. At last, the LSTM model was trained by the training set, and the prediction results on the crack path were compared with the test set. The results show that this method can be used to predict the crack propagation path rapidly and accurately. In general, this article explores the application of machine learning related technologies in the field of mechanics. It has broad application prospects in the fields of damage assessment and vulnerability analysis.

• 한국디지털건축인테리어학회논문집
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• 제8권2호
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• pp.13-20
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• 2008

As buildings have been constructed higher and more complicated recently, the activities of the residents occurred in those multiplex buildings have also become more various. As a result, possibility and the size of the damage from the disaster like a fire are getting larger. So, many studies for preventing the damage in refuge situation are being conducted. In this study, a new process for finding the optimum refuge path is presented, which is different from existing methods. This new method operates by using the human movement detection system in the building for real time. And the process also shows the new way which can shorten the number of calculation for deciding the optimum refuge path. That new way is to make variables such as the velocity of smoke and person movement into a constant. Finally it will be applied to a multiplex building.

• The Journal of Advanced Prosthodontics
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• 제7권1호
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• pp.76-84
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• 2015

This article reviews the topic of how to identify and develop a removable partial denture (RPD) path of placement, and provides a literature review of the concept of the RPD path of placement, also known as the path of insertion. An optimal RPD path of placement, guided by mutually parallel guide planes, ensures that the RPD flanges fit intimately over edentulous ridge structures and that the framework fits intimately with guide plane surfaces, which prevents food collecting empty spaces between the intaglio surface of the framework and intraoral surfaces, and ensures that RPD clasps engage adequate numbers of tooth undercuts to ensure RPD retention. The article covers topics such as the causes of obstructions to RPD intra-oral seating, the causes of food collecting empty spaces that may exist around an RPD, and how to identify if a guide plane is parallel with the projected RPD path of placement. The article presents a method of using a surgical operating microscope, or high magnification (6-8x or greater) binocular surgical loupes telescopes, combined with co-axial illumination, to identify a preliminary path of placement for an arch. This preliminary path of placement concept may help to guide a dentist or a dental laboratory technician when surveying a master cast of the arch to develop an RPD path of placement, or in verifying that intra-oral contouring has aligned teeth surfaces optimally with the RPD path of placement. In dentistry, a well-fitting RPD reduces long-term periodontal or structural damage to abutment teeth.