• 제목/요약/키워드: Damage class

검색결과 289건 처리시간 0.024초

Effects of curvature radius on vulnerability of curved bridges subjected to near and far-field strong ground motions

  • Naseri, Ali;Roshan, Alireza MirzaGoltabar;Pahlavan, Hossein;Amiri, Gholamreza Ghodrati
    • Structural Monitoring and Maintenance
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    • 제7권4호
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    • pp.367-392
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    • 2020
  • The specific characteristics of near-field earthquake records can lead to different dynamic responses of bridges compared to far-field records. However, the effect of near-field strong ground motion has often been neglected in the seismic performance assessment of the bridges. Furthermore, damage to horizontally curved multi-frame RC box-girder bridges in the past earthquakes has intensified the potential of seismic vulnerability of these structures due to their distinctive dynamic behavior. Based on the nonlinear time history analyses in OpenSEES, this article, assesses the effects of near-field versus far-field earthquakes on the seismic performance of horizontally curved multi-frame RC box-girder bridges by accounting the vertical component of the earthquake records. Analytical seismic fragility curves have been derived thru considering uncertainties in the earthquake records, material and geometric properties of bridges. The findings indicate that near-field effects reasonably increase the seismic vulnerability in this bridge sub-class. The results pave the way for future regional risk assessments regarding the importance of either including or excluding near-field effects on the seismic performance of horizontally curved bridges.

A study on Natural Disaster Prediction Using Multi-Class Decision Forest

  • Eom, Tae-Hyuk;Kim, Kyung-A
    • 한국인공지능학회지
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    • 제10권1호
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    • pp.1-7
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    • 2022
  • In this paper, a study was conducted to predict natural disasters in Afghanistan based on machine learning. Natural disasters need to be prepared not only in Korea but also in other vulnerable countries. Every year in Afghanistan, natural disasters(snow, earthquake, drought, flood) cause property and casualties. We decided to conduct research on this phenomenon because we thought that the damage would be small if we were to prepare for it. The Azure Machine Learning Studio used in the study has the advantage of being more visible and easier to use than other Machine Learning tools. Decision Forest is a model for classifying into decision tree types. Decision forest enables intuitive analysis as a model that is easy to analyze results and presents key variables and separation criteria. Also, since it is a nonparametric model, it is free to assume (normality, independence, equal dispersion) required by the statistical model. Finally, linear/non-linear relationships can be searched considering interactions between variables. Therefore, the study used decision forest. The study found that overall accuracy was 89 percent and average accuracy was 97 percent. Although the results of the experiment showed a little high accuracy, items with low natural disaster frequency were less accurate due to lack of learning. By learning and complementing more data, overall accuracy can be improved, and damage can be reduced by predicting natural disasters.

Fragility-based rapid earthquake loss assessment of precast RC buildings in the Marmara region

  • Ali Yesilyurt;Oguzhan Cetindemir;Seyhan O. Akcan;Abdullah C. Zulfikar
    • Structural Engineering and Mechanics
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    • 제88권1호
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    • pp.13-23
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    • 2023
  • Seismic risk assessment studies are one of the most crucial instruments for mitigating casualties and economic losses. This work utilizes fragility curves to evaluate the seismic risk of single-story precast buildings, which are generally favored in Marmara's organized industrial zones. First, the precast building stock in the region has been categorized into nine sub-classes. Then, seven locations in the Marmara region with a high concentration of industrial activities are considered. Probabilistic seismic hazard assessments were conducted for both the soil-dependent and soil-independent scenarios. Subsequently, damage analysis was performed based on the structural capacity and mean fragility curves. Considering four different consequence models, 630 sub-class-specific loss curves for buildings were obtained. In the current study, it has been determined that the consequence model has a significant impact on the loss curves, hence, average loss curves were computed for each case investigated. In light of the acquired results, it was found that the loss ratio values obtained at different locations within the same region show significant variation. In addition, it was observed that the structural damage states change from serviceable to repairable or repairable to unrepairable. Within the scope of the study, 126 average loss functions were presented that could be easily used by non-experts in earthquake engineering, regardless of structural analysis. These functions, which offer loss ratios for varying hazard levels, are valuable outputs that allow preliminary risk assessment in the region and yield sensible outcomes for insurance activities.

"상한전생집(傷寒全生集).변상한발열례(辨傷寒發熱例)" 등에 대한 연구(硏究) (A Research on The Pulse & Disease-patterns and Diagnostic Theory of Exogenous Febrile Disease in the "Sanghanjeonsaengjip(傷寒全生集)")

  • 최동수;신영일
    • 대한한의학원전학회지
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    • 제23권4호
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    • pp.103-153
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    • 2010
  • "Sanghanjeonsaengjip(傷寒全生集)" is a classic medical work, written by the outstanding physician Dohwa(陶華) in the Ming Dynasty. The characteristic of "SangHanJeonSaengJip" is that this book succeeded to the spirit of pattern identification and treatment of Treatise on Cold Damage Diseases, newly changed a table of contents by symptoms, and together with this indicated the prescriptions in accordance with diswase-pattern at "YujeunghwalInseo(類證活人書)", "Hwajegookbang(和劑局方)" etc. Also because this kept the existing ephedra decoction, cinnamom twig decoction, minor decoction of bupleurum, decoction for reinforcing middle-energizer and replenishing qi etc.'s name on and unlikely indicated the medicine composition, it caused confusion, but at the later ages "Euhakipmun(醫學入門)" the so-called 'Doci(陶氏)' was added to the prescription name, so we are able to distinguish. Together with this, this book dose not indicate the dosage of medicine and indicates the first, the second, and the third classes[上中下] below medicine. As this dose not mean the three grades of quality"good, fair, and poor[上中下] of "Shennong's Classic of Materia Medica" but expresses the sovereign medicinal as the first class[上], minister medicinal as the second class[中] and assistant and courier medicinal as the third class[下], doctors can voluntarily decide the dosage of medicine in accordance with the degree of disease. At this thesis, I single out ten chapters in contents of 2nd volume named Hyeong(亨) corresponding to the details, among "Sanghanjeonsaengjip(傷寒全生集)". I discussed superficial fever types of exogenous febrile disease in chapter 1, aversion to cold types of exogenous febrile disease in chapter 2, syndrome caused un-sufficient sweating in chapter 3, organic fever types of exogenous febrile disease in chapter 4, aversion to wind types of exogenous febrile disease in chapter 5, Tidal fever types of exogenous febrile disease in chapter 6, Alternative attacts of chills and fever in chapter 7, Dysphoria with smothery sensation in chapter 8, Fidgetiness of exogenous febrile disease in chapter 9, and Headache of exogenous febrile disease in chapter 10, and together with this I discussed, in detail, which influence the prescriptions which are listed on each chapter have caused on future generations In accordance with this, I think that the above-mentioned symptoms and prescriptions are important when I research cold damage and warm disease study. So I orderly research revision, annotation, rendering and an investigation.

초등학생의 성격특성과 학교안전사고 (The Relationship between the Personality of Elementary School Students and the Safety Accidents in the School)

  • 김창희;박영수
    • 한국학교ㆍ지역보건교육학회지
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    • 제4권
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    • pp.1-20
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    • 2003
  • This study was not intended to analyze out the realities of the safety accidents in school. The purpose of this study was to find out the personality of elementary school students in 6th grade and analyze the relationship between the personality of elementary school students and the safety accidents in the school. We made a visit 12 elementary school personally in the B city of Gyeonggi Province and gave out 552 questionaries in order to accomplish the purpose of this study. And we analyzed the 501 answer data except the unfittable data 51 sheets-in case of no answer or untruthfulness. The inspection of the personality used the Eysenck Personality Questionnaire(EPQ) and the questionnaires of the safety accidents in the school were reorganized of the questionnaires which were used in Chun-Ok, Joen(1997) and One-Yong, Kim(1999)'s study to correspond with our purpose of study. Answer sheets were gone through the t and x2 test by using the program of SPPS. First, elementary school students are in the formative period in the life of a man. So many students's personality was in the middle group rather than in high and low group. In regard of the distintion between the boy students and the girl students, the boy students had higher score in Psychoticism(P) but the girl students had higher score in Neutroticism(N). And Lie(L) was showing a little more score in the girl students. Second, there was significant difference in the investigation of safety accidents in school according to sex distinction. 1) Comparing the boy students and the girl students, the rate of accidents was higher in boy rather than girl. And there was significant difference. 2) Comparing the grade of the school, the rate of accidents was higher in upper grade than lower grade both girls and boys. 3) In the kind of accidents, the traumatic Injuries were very popular and the next were contusions. There was significant difference in the traumatic injury and nosebleed. 4) The results of injured parts showed that the injuries of foot, leg, hand, arm hold a large majority. And there was a significant difference in head, face, foot, leg and etc. 5) Most accidents broke out during the break time and then accidents happened after school were the next. The flowings were lunch time and class time. There was a significant difference in accidents happened during the class, break time and lunch time. 6) Comparing the subjects, the most accidents broke out in the class of physics. 7) Among the cause of accidents, one's own carelessness was showing the highest rate. There was a significant distintion in the fight and game. 8) The safety accidents took place most in playground, and there was a significant difference. 9) Being slight wound was showing almost in the degrees of damage. And there was a significant difference. Third, the boy students were not showing the significant difference in relation to the personality, the frequency of accidents and the degrees of damage. But the girl students were showing the significant difference in relation to the Extraversion-Introversion(E) and the frequency of accidents. And there were a significant difference between E and N. Also they were showing the intense damages.

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가습기살균제 피해신청자들의 노출등급 분류 및 폐질환 발생 영향요인 분석 (Affecting Factors of Lung Disease and Classification of Exposure Rating of Applicants for Injuries from Humidifier Disinfectants)

  • 민기홍;신정현;조은경;정다영;류지윤;김동준;우재민;배성호;신지훈;이슬아;최윤형;양원호
    • 한국환경보건학회지
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    • 제48권6호
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    • pp.324-330
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    • 2022
  • Background: Lung injuries due to exposure to humidifier disinfectants (HDs) were reported in 2011 in South Korea. As a result of the government's epidemiological investigation and toxicity test study, it was found that HDs caused health damage such as lung disease. Objectives: The purpose of this study was to classify HD exposure ratings and analyze the affecting factors that could identify the relationship with lung disease. Methods: Exposure assessment for HDs was conducted using a questionnaire during face-to-face interviews with the applicants. Ratings of high exposure (Class 1) and low exposure (Class 2) were cross-tabulated with clinical ratings (acceptable and unacceptable). Logistic regression analysis was carried out by setting the clinical rating of lung disease as a dependent variable and the socio-demographic and exposure characteristics obtained through the questionnaire as independent variables. Results: The concentration in air of polyhexamethylene guanidine (PHMG) was 71.96±107.47 ㎍/m3, and the exposure concentration was 15.21±23.28 ㎍/m3 . The exposure rating was overestimated with 97.1% of affected subjects having high exposure using margin of exposure (MOE), but only 9.9% matching the clinical class. In the overestimated group, it could be explained by the fact that the exposure time was long and the subjects had already recovered from damage symptoms. As a result of logistic regression analysis, ten variables were found to be significant influencing factors. Conclusions: A new exposure rating could be calculated based on the MOE, and factors affecting lung disease could be estimated through comparative evaluation with the clinical rating.

초안산근린공원 숲길 훼손 실태 및 복원방안 연구 (Status of Damage and Restoration Planning of Forest Trail in Choansan(Mt.) Neighborhood Park, Seoul, South Korea)

  • 한봉호;기경석;노태환
    • 한국환경생태학회지
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    • 제26권6호
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    • pp.923-933
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    • 2012
  • 본 연구는 최근 이용압력이 높은 서울시 초안산근린공원을 대상으로 숲길의 분포와 훼손 실태를 파악하여 향후 도심 내 숲길 정비 방향을 설정하기 위한 목적으로 수행하였다. 초안산근린공원 숲길(25,964m)의 훼손 현황 중 노폭 2m 이상 20.3%, 침식 깊이 30cm 이상 36.3%, 훼손이 심한 형태인 나지침식이나 근계노출, 암석노출 구간 47.0%이었고, 환경피해도 등급 IV 이상이 70.6%로 숲길 훼손이 심각한 상태이었다. 훼손이 심한 숲길 노선은 대부분 주능선을 따라 형성된 주요 숲길과 저지대 급경사 숲길, 주요 숲길과 연결된 샛길이었다. 연구결과에 기초하여 초안산근린공원 숲길의 복원유형을 숲길 확산방지, 숲길 지반안정, 숲길 노면정비, 숲길 폐쇄 후 식생복원, 유지 등 5가지로 구분하였고, 유형별 복원방안을 제안하였다. 숲길 확산방지는 나지가 노출되어 있는 숲길 폭원 확대를 방지하고, 숲길 지반안정은 숲길 내 침식 및 뿌리노출을 방지하며, 숲길 노면정비는 훼손이 심각한 숲길의 노면을 목재데크, 목재계단, 노면 포장 실시 등을 통하여 보호하기 위한 계획을 수립하였다.

전문경호비서의 직업윤리에 관한 연구 (A Study on the Vocational Ethics of Security and Secretary Service)

  • 박옥철
    • 한국재난정보학회 논문집
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    • 제3권2호
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    • pp.55-78
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    • 2007
  • Currently, the departments related to security and secretary service exist in 18 universities and 30 colleges in Korea in order to raise professional security and secretary personnel. Among the 18 four-year colleges in Korea, only two of them have the ethics course include in their curriculum. Also, among the 31 two-year colleges, only three of them have the ethics course included in their curriculum. Besides, as some private security and guardian companies were recently utilized in illegal actions of the rich and ruling class, contradicting their original purpose of existence, many people point out their downfall as a ?forced private army.? As a professional job, if security secretaries take advantage of the knowledge and top-secret technologies and use them for non-ethical purposes, the effect of the damage is far more serious than other fields of jobs. Therefore, taking this event as a turning point, the contract contents and the task area between the client and the security and secretary company must become more transparent in order to prevent illegal actions, and also for the people working in the security and secretary service area, it is necessary to establish a firm ethical consciousness in order to behave appropriately in their working environment. Therefore, this study examines the proper direction of work ethics of the people working in the security and secretary service according to the professionalization of their field, and also aims to propose an appropriate work ethic system such that they will not become an unfortunate victim of various scandals anymore. To do so, the concept of work ethics in professional jobs was examined; and after the code of ethics that reflect the ethical value system of each professional job was reviewed, the study suggested a specific solution for establishing the codes of ethics for security and secretary service.

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22.9[kV]이하 XLPE 전력케이블의 열 충격 시험 및 절연파괴 특성 (The Properties of Dielectric Breakdown and Thermal Stresses below 22.9[kV] Class XLPE Power Cable)

  • 김영석;송길목;김선구
    • 조명전기설비학회논문지
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    • 제22권4호
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    • pp.54-60
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    • 2008
  • 2002년부터 시행되어오고 있는 제조물 책임법에 의해 사고케이블의 원인분석과 사고패턴에 대한 데이터베이스화가 중요하다. 더욱이 가속열화상태에서 전력케이블 사고의 패턴 및 모의실험은 데이터베이스 시스템 구축에 필요하다. 본 논문에서는 열 열화 따른 22.9[kV]이하 케이블의 열 충격시험을 수행하였다. 이 시험은 IEC60811-3-1에 따른다. 시험결과로부터, 22.9[kV]급 A사 전력케이블은 표면이 변색되었고 길이방향으로 급격하게 감소되었다. 특히, A사 전력케이블의 열 중량 특성이 심하게 변함에 따라, 케이블 제조상의 문제일 것이라 추측된다. 만약 전력케이블의 제조상의 결함에 의한 것이라면, 피해자들은 PL환경 하에 손해배상을 받을 수 있을 것이다.

설문에 의한 6급 기관사 면허 면접시험 응시자의 성향 분석 (Propensity Analysis for Oral Exam Candidates of Sixth Class Engineer Officer's License using Questionnaire)

  • 박태건;이유원;김용복
    • 수산해양교육연구
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    • 제26권5호
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    • pp.1151-1157
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    • 2014
  • The propensity analysis for oral exam candidates of sixth class engineer officer's license was conducted to serve as a basic data for improving the ability of seamanship and a stable workforce supply using a questionnaire. A general information of them was identified as 62.1% of offshore fishing, 59.3% of over 50, 59.4% of less middle school education, 52.4% of under 100 gross tonnage, 75.2% of under 1,500kW engine output, 72.5% of over 10 years experience, 72.4% of engine department, which means they are from mainly less than 100 gross tonnage of offshore fishing vessel, less educated, and long term experienced in the engine job. The reason why they took the test was mainly due to their will (51.7%). And 45.5% of them took the test for the first time, 45.5% of answers responded they are lack of knowledge about a written exam and text of KIMFT in preparation data for an oral exam 35.9%. Given the fact that 74.5% of respondents experienced marine accidents with engine damage on board, the need for marine casualty reduction education was verified. Even after obtaining a license, they showed a higher preference of boarding that they embarked before the examination. Also, 61.4% of them have a plan for long-term boarding at least three years, thus leading to supply of workforce in coastal and offshore areas.