• Earthquakes and Structures
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• 제14권6호
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• pp.615-626
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• 2018

The seismic vulnerability of Turkey is relatively high due to its active fault systems with potential to create destructive earthquakes. Thus, reducing the loss of life and property, the number of the earthquake-prone buildings and their retrofit requirements are considerably significant key issues under the scenario earthquakes. The street survey based rapid assessment (SSRA) method can be considered as a powerful tool to determine the seismic vulnerability of building stock of an earthquake-prone city/state. In this study, the seismic vulnerability of the building stock of the Kirikkale province in Turkey is aimed to be estimated adopting the street survey based rapid assessment method (SSRA). For this purpose, central 2074 existing reinforced concrete (R/C) buildings were structurally surveyed with rapid visual site screening and disadvantages such as, the existence of short-column, soft-story, heavy overhangs, pounding effect and local soil conditions were determined for obtaining the structural performance score of each. The results obtained from the study demonstrate that 11-25% of the surveyed buildings in the study region needs to be investigated through more advanced assessment methods. Besides, higher correlation between increasing story number and unsafe/safe building ratio is obtained for the buildings with soft-story parameter than that for those with heavy overhangs and short-column parameters. The conformity of the results of the current study with the previous documented cases of rapid assessment efforts in the recent earthquakes in Turkey shows that the SSRA method for the Kirikkale province performed well, and thus this methodology can be reliably used for similar settlement areas.

• Nuclear Engineering and Technology
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• 제41권5호
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• pp.747-752
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• 2009

A vulnerability assessment is essential for the efficient operation of a physical protection system (PPS). Previous assessment codes have used a simple model called an adversary sequence diagram. In this study, the use of a two-dimensional (2D) map of a facility as a model for a PPS is suggested as an alternative approach. The analysis of a 2D model, however, consumes a lot of time. Accordingly, a generalized heuristic algorithm has been applied to address this issue. The proposed assessment method was implemented to a computer code; Systematic Analysis of physical Protection Effectiveness (SAPE). This code was applied to a variety of facilities and evaluated for feasibility by applying it to various facilities. To help upgrade a PPS, a sensitivity analysis of all protection elements along a chosen path is proposed. SAPE will help to accurately and intuitively assess a PPS.

• 한국수자원학회논문집
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• 제46권2호
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• pp.99-109
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• 2013

유역 환경에 대한 복잡성의 증가는 단일 의사결정자들이 의사결정문제의 모든 부분을 고려하는 것을 점점 더 불가능하게 만들기 때문에 불확실성은 더욱 증가하게 된다. 따라서 본 연구는 그룹의사결정기법을 사용하여 우리나라 공간적인 홍수 취약성을 정량화하는 접근법을 제시하였다. 개인의 선호도를 분석하기위해 Fuzzy TOPSIS를 사용하였고 개인선호도의 통합을 위해 Borda count, Condorcet 그리고 Copeland 방법을 사용하였다. 마지막으로 도출된 결과를 Fuzzy TOPSIS 및 TOPSIS의 결과와 비교하였고 스피어만 순위상관계수와 켄달의 순위상관계수, Emond와 Mason이 제시한 순위상관분석을 이용하여 순위의 일치성을 검토하였다. 그 결과 일부 지역의 취약성 순위가 큰 폭으로 역전되는 현상을 보였다. 그룹의사결정 개념을 반영하여 지역별 취약성을 산정할 경우 우선순위의 변동이 클 수 있으므로 홍수 취약성 산정시 본 연구에서 제시된 모델을 고려할 필요가 있다.

• 한국CDE학회논문집
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• 제22권2호
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• pp.141-149
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• 2017

Vulnerability assesses the loss of major performance functions of GCV (Ground Combat Vehicles) when it is hit by enemy's shell. To decide the loss of major functions, it is determined what effects are on the performance of GCV when some components of GCV are failed. M&S (Modeling and Simulation) technology is used to vulnerability assessment. The hydro-pneumatic suspension is used as a sample part. The procedures of vulnerability assessment of the hydro-pneumatic suspension are shown as follows: 1) The components of the suspension are defined, and shot lines are generated evenly around the part. 2) The penetrated components are checked by using the penetration equation. 3) The function model of the suspension is designed by using IDEF0. 4) When the failure of the critical components of the suspension happens, its effect on the function of the suspension can be estimated using DMEA (Damage Mode and Effects Analysis). 5) The diagram of FTA (Fault Tree Analysis) is designed by exploiting DMEA. 6) The damage probability of the suspension is calculated by using FTA and vulnerable area method. In this paper, SLAP (Shot Line Analysis Program) which was developed based on COVART methodology. SLAP calculates the damage probability and visualizes the vulnerable areas of the suspension.

• Earthquakes and Structures
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• 제9권4호
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• pp.719-733
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• 2015

Seismic risk management of the built environment is integrated by two main stages, the assessment and the remedial measures to attain its reduction, representing both stages a complex task. The seismic risk of a certain structure located in a seismic zone is determined by the conjunct of the seismic hazard and its structural vulnerability. The hazard level mainly depends on the proximity of the site to a seismic source. On the other hand, the ground shaking depends on the seismic source, geology and topography of the site, but definitely on the inherent earthquake characteristics. Seismic hazard characterization of a site under study is suggested to be estimated by a combination of studies with the history of earthquakes. In this Paper, the most important methods of seismic vulnerability evaluation of buildings and their application are described. The selection of the most suitable method depends on different factors such as number of buildings, importance, available data and aim of the study. These approaches are classified in empirical, analytical, experimental and hybrid. For obtaining more reliable results, it is recommends applying a hybrid approach, which consists of a combination between methods depending on the case. Finally, a recommended approach depending on the building importance and aim of the study is described.

• Journal of Multimedia Information System
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• 제4권2호
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• pp.57-64
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• 2017

Numerous software vulnerabilities have been found in the popular operating systems. And recently, robust linear behaviors in software vulnerability discovery process have been noticeably observed among the many popular systems having multi-versions released. Software users need to estimate how much their software systems are risk enough so that they need to take an action before it is too late. Security vulnerabilities are discovered throughout the life of a software system by both the developers, and normal end-users. So far there have been several vulnerability discovery models are proposed to describe the vulnerability discovery pattern for determining readiness for patch release, optimal resource allocations or evaluating the risk of vulnerability exploitation. Here, we apply a linear vulnerability discovery model into Windows operating systems to see the linear discovery trends currently observed often. The applicability of the observation form the paper show that linear discovery model fits very well with aggregate version rather than each version.

• 한국물환경학회지
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• 제28권3호
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• pp.444-452
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• 2012

This study aims at assessing vulnerability of water quality and aquatic ecosystem to climate change by using proxy variables. Vulnerability to climate change is defined as a function of exposure to climate, sensitivity, and adaptive capacity. Detailed proxy variables were selected considering availability and then standardized by re-scaling concept. After adequate weights were assigned to standardized proxy variables by Delphi technique, vulnerability index was calculated. As results, vulnerability of adjacent regions to coastal areas include water quality and aquatic ecosystem is relatively higher than that of inland areas, and especially adjacent region to the western and southeast seas, and Jeju show high vulnerabilities. Vulnerability in the future was performed based on A1B scenario (IPCC, 2000). Temporally, the increase of vulnerability from 2050s to 2100s may be larger than the increase from 2000s to 2050s. Because vulnerability index was estimated through the relationship among various proxy variables, it is important to consider characteristics of local region with measurements and policies for reduction of sensitivity and enhancement of adaptive capacity on climate change. This study is expected to be useful in planning adaptation measures and selecting priority to the policy on climate change.

• 한국지하수토양환경학회지:지하수토양환경
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• 제18권5호
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• pp.26-38
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• 2013

In this study, priority for groundwater contamination management was assessed based on regional vulnerability in Goyang-si area, Gyonggi-do, Korea using analytic hierarchy process (AHP) and geographic information system (GIS). We proposed a concept for regional vulnerability to groundwater contamination with using socio-environmental vulnerability factors, which can be classified into three properties including regional hydrogeological property, contamination property, and groundwater use property. This concept is applied to Goyang-si area. For AHP analysis, an expertise-targeted survey was conducted. Based on the survey, a total of 10 factors (criteria) and corresponding weights for regional vulnerability assessment were determined. The result shows that regional contamination property is the most weighted factor among the three property groups (hydrogeological property: contamination property: groundwater use property = 0.3: 0.4: 0.3). Then, database layers for those factors were constructed, and regional vulnerability to groundwater contamination was assessed by weighted superposition using GIS. Results show that estimated regional vulnerability score is ranged from 22.7 to 94.5. Central and western areas of Goyang-si which have groundwater tables at shallow depths and are mainly occupied by industrial and residential areas are estimated to be relatively highly vulnerable to groundwater contamination. Based on assessed regional vulnerability, we classified areas into 4 categories. Category 1 areas, which are ranked at the top 25% of vulnerability score, take about 2.8% area in Goyang-si and give a high priority for groundwater contamination management. The results can provide useful information when the groundwater management authority decide which areas should be inspected with a high priority for efficient contamination management.

• 정보보호학회논문지
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• 제31권4호
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• pp.779-791
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• 2021

보통의 웹 서비스는 불특정 다수에게 허용을 해야하는 접근 통제 정책으로 인하여, 지속적으로 해커들의 공격 대상이 되어 왔다. 이러한 상황에 대응하고자 기업들은 주기적으로 웹 취약점 점검을 실시하고, 발견된 취약점의 위험도에 따라 조치를 취하고 있다. 이러한 웹 취약점 위험도는 국내외 유관기관의 사전 통계 및 자체적인 평가를 통해 산정되어 있다. 하지만 웹 취약점 점검은 보안설정 및 소스코드 등의 정적 진단과는 달리 동적 진단으로 이루어진다. 동일한 취약점 항목일지라도 다양한 공격 결과를 도출할 수 있으며, 진단 대상 및 환경에 따라 위험도가 달라질 수 있다. 이러한 점에서 사전 정의된 위험도는 실제 존재하는 취약점의 위험도와는 상이할 수 있다. 본 논문에서는 이러한 점을 개선하고자 사이버 킬체인 중심으로 공격 결과 기반의 웹 취약점 위험도 평가 모델을 제시한다.

• Structural Engineering and Mechanics
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• 제77권4호
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• pp.441-461
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• 2021

Reinforced concrete (RC) columns are crucial in building structures and they are of higher vulnerability to terrorist threat than any other structural elements. Thus it is of great interest and necessity to achieve a comprehensive understanding of the possible responses of RC columns when exposed to high intensive blast loads. The primary objective of this study is to derive analytical formulas to assess vulnerability of RC columns using an advanced numerical modelling approach. This investigation is necessary as the effect of blast loads would be minimal to the RC structure if the explosive charge is located at the safe standoff distance from the main columns in the building and therefore minimizes the chance of disastrous collapse of the RC columns. In the current research, finite element model is developed for RC columns using LS-DYNA program that includes a comprehensive discussion of the material models, element formulation, boundary condition and loading methods. Numerical model is validated to aid in the study of RC column testing against the explosion field test results. Residual capacity of RC column is selected as damage criteria. Intensive investigations using Arbitrary Lagrangian Eulerian (ALE) methodology are then implemented to evaluate the influence of scaled distance, column dimension, concrete and steel reinforcement properties and axial load index on the vulnerability of RC columns. The generated empirical formulae can be used by the designers to predict a damage degree of new column design when consider explosive loads. With an extensive knowledge on the vulnerability assessment of RC structures under blast explosion, advancement to the convention design of structural elements can be achieved to improve the column survivability, while reducing the lethality of explosive attack and in turn providing a safer environment for the public.