• 한국지하수토양환경학회지:지하수토양환경
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• 제18권3호
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• pp.119-133
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• 2013

In the present study, several groundwater vulnerability assessment methods were applied to an agricultural area of Gumma in Korea. For the groundwater intrinsic vulnerability assessment, the performance of DRASTIC, SINTACS and GOD models was compared and an ensemble approach was suggested. M-DRASTIC and multi-linear regression (MLR) models were applied for the groundwater specific vulnerability assessment to nitrate of the study site. The correlation coefficient between the nitrate concentration and M-DRASTIC index was as low as 0.24. The result of the MLR model showed that the correlation coefficient is 0.62 and the areal extents of livestock farming and upland field are most influential factors for the nitrate contamination of groundwater in the study site.

• 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.

• Earthquakes and Structures
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• 제21권6호
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• pp.627-639
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• 2021

Fragility curves are being more significant as a useful tool for evaluating the relationship between the earthquake intensity measure and the effects of the engineering demand parameter on the buildings. In this paper, the effect of different site conditions on the vulnerability of the structures was examined through the fragility curves taking into account different strength capacities of the precast columns. Thus, typical existing single-story precast RC industrial buildings which were built in Turkey after the year 2000 were examined. The fragility curves for the three typical existing industrial structures were derived from an analytical approach by performing non-linear dynamic analyses considering three different soil conditions. The Park and Ang damage index was used in order to determine the damage level of the members. The spectral acceleration (Sa) was used as the ground motion parameter in the fragility curves. The results indicate that the fragility curves were derived for the structures vary depending on the site conditions. The damage probability of exceedance values increased from stiff site to soft site for any Sa value. This difference increases in long period in examined buildings. In addition, earthquake demand values were calculated by considering the buildings and site conditions, and the effect of the site class on the building damage was evaluated by considering the Mean Damage Ratio parameter (MDR). Achieving fragility curves and MDR curves as a function of spectral acceleration enables a quick and practical risk assessment in existing buildings.

• Structural Engineering and Mechanics
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• 제26권6호
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• pp.617-634
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• 2007

Algeria is a country with a high seismic activity. During the last decade, many destructive earthquakes occurred, particularly in the northern part, causing enormous losses in human lives, buildings and equipments. In order to reduce this risk in the capital and avoid serious damages to the strategic existing buildings, the government decided to invest into seismic upgrade, strengthening and retrofitting of these buildings. In doing so, seismic vulnerability study of this category of buildings has been considered. Structural analysis is performed on the basis of site investigation (inspection of the building, collecting data, materials, general conditions of the building, etc), and existing drawings (architectural plans, structural design, etc). The aim of these seismic vulnerability studies is to develop guidelines and a methodology for rehabilitation of existing buildings. This paper will provide insight to the vulnerability assessment and strengthening of the telecommunication centre, according to the new code RPA 99/version 2003. Both, static equivalent method and non linear dynamic analysis are performed in this study.

• 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.

• 전기학회논문지
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• 제67권10호
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• pp.1271-1277
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• 2018

This paper deals with a voltage sag assessment based on a voltage monitoring program. The voltage sag performance at a specific site can be evaluated by analyzing voltage monitoring data recorded for a long time period. Although an assessment based on voltage monitoring is an effective way to understand voltage sag performance at a measurement site, the statistical confidence of voltage sag frequency estimation heavily depends on the length of monitoring period and the number of recorded events. Short monitoring period and insufficient recorded data can not provide a reliable assessment result. This paper proposes a compensation assessment method by combining a computer simulation approach for in case that monitoring period and data are not enough for a valid assessment.

• 한국소프트웨어감정평가학회 논문지
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• 제17권2호
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• pp.125-142
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• 2021

Reports of rampant cross-site scripting (XSS) vulnerabilities raise growing concerns on the effectiveness of current Static Analysis Security Testing (SAST) tools as an internet security device. Attentive to these concerns, this study aims to examine seven open-source SAST tools in order to account for their capabilities in detecting XSS vulnerabilities in PHP applications and to determine their performance in terms of effectiveness and analysis runtime. The representative tools - categorized as either text-based or graph-based analysis tools - were all test-run using real-world PHP applications with known XSS vulnerabilities. The collected vulnerability detection reports of each tool were analyzed with the aid of PhpStorm's data flow analyzer. It is observed that the detection rates of the tools calculated from the total vulnerabilities in the applications can be as high as 0.968 and as low as 0.006. Furthermore, the tools took an average of less than a minute to complete an analysis. Notably, their runtime is independent of their analysis type.

• 대한원격탐사학회지
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• 제37권3호
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• pp.649-655
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• 2021

본 연구는 경주시를 대상으로 수행한 선행연구를 바탕으로 도출된 최적의 지진 취약성 평가 모델을 타 지역에 적용하여 그 성능을 교차 검증(cross-validation)하고자 한다. 테스트 지역은 2017 포항지진(Pohang Earthquake)이 발생한 포항시이며, 선행연구와 동일한 영향인자 및 피해현황 관련 데이터셋을 구축하였다. 검증 데이터 셋은 무작위로 추출해 구축하였으며, 경주시의 랜덤 포레스트(random forest, RF) 기반의 모델에 적용하여 예측 정확도를 도출하였다. 경주시의 모델(success) 및 예측(prediction) 정확도는 100%, 94.9%이며, 포항시 검증 데이터 셋을 적용해 예측 정확도를 확인한 결과 70.4%로 나타났다.

• 한국안전학회지
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• 제33권5호
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• pp.150-156
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• 2018

As the types and usage of chemical increase, modern countries should protect their health and environment from the risk of hazardous chemical. Chemical accidents not only affect humans but also cause huge losses to the environment. Moreover, since its effects do not end in a short period of time, it is necessary to identify the extent of the damage and establish a prevention and response system in advance. In 2015, the Chemical Substances Management Act provided a system for assessing the impact on the people and the environment around the workplace. However, it is difficult to quantitatively evaluate the impact on environmental factors such as vegetation and aquatic, with the current hazard assessment methods. The purpose of this study is to analyze the quantitative risk of environmental receptors. This study improved the existing risk assessment formula by using the environmental vulnerability index and established the end point concentration criterion which can estimate the damage range to environmental media. To verify the results of the study, a virtual accident scenario was selected and a case study was conducted. As a result, the extent of impact on the environmental medium can be calculated, and the degree of environmental risk of the zone can be quantified through the risk analysis considering the environmental vulnerability. This study is expected to increase the reliability of the reliability of the existing risk anaylsis method beacause it is a risk analysis method that can be applied when the environmental factors are absolutely necessary and when the residents and environment are complex.

• Earthquakes and Structures
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• 제11권2호
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• pp.371-386
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• 2016

During the last decades, many destructive earthquakes occurred in Algeria, particularly in the northern part of the country (Chlef (1980), Constantine (1985), Tipaza (1989), Mascara (1994), Ain-Benian (1996), Ain Temouchent (1999), Beni Ourtilane (2000), and recently $Boumerd{\acute{e}}s$ (2003), causing enormous losses in human lives, buildings and equipments. In order to reduce this risk and avoid serious damages to the strategic existing buildings, the authorities of the country, aware of this risk and in order to have the necessary elements that let them to know and estimate the potential losses in advance, with an acceptable error, and to take the necessary countermeasures, decided to invest into seismic upgrade, strengthening and retrofitting of those buildings. To do so, seismic vulnerability study of this category of buildings has been considered. Structural analysis is performed based on the site investigation (inspection of the building, collecting data, materials characteristics, general conditions of the building, etc.), and existing drawings (architectural plans, structural design, etc.). The aim of these seismic vulnerability studies is to develop guidelines and a methodology for rehabilitation of existing buildings. This paper presents the methodology, based on non linear and seismic analysis of existing buildings, followed in this study and summarizes the vulnerability assessment and strengthening of one of the strategic buildings according to the new Algerian code RPA 99/version 2003. As a direct application of this methodology, both, static equivalent method and non linear dynamic analysis, of composite concrete masonry existing building in the city of "CONSTANTINE", located in the east side of ALGERIA, are presented in this paper.