• Title/Summary/Keyword: hazard levels

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A Study on the Safety Requirements Establishment through System Safety Processes (시스템 안전성평가를 통한 효율적 요건 도출방안 연구)

  • Yoo, Seung-woo;Jung, Jinpyong;Yi, Baeck-Jun
    • Journal of Aerospace System Engineering
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    • v.7 no.2
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    • pp.29-34
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    • 2013
  • Safety requirements for aircraft and system functions include minimum performance constraints for both availability and integrity of the function. These safety requirements should be determined by conducting a safety assessment. The depths and contents of aircraft system safety assessment vary depending on factors such as the complexity of the system, how critical the system is to flight safety, what volume of experience is available on the type of system and the novelty and complexity of the technologies being used. Requirements that are defined to prevent failure conditions or to provide safety related functions should be uniquely identified and traceable through the levels of development. This will ensure visibility of the safety requirements at the software and electronic hardware design level. This paper has prepared to study on promoting the efficiency of establishing hierarchical safety requirements from aircraft level function to item level through system safety processes.

Safety Levels Apportionment in Railway System

  • Rafrafi, Meriem;El Koursi, El Miloudi;Bourdeaud'Huy, Thomas
    • International Journal of Railway
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    • v.1 no.4
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    • pp.157-168
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    • 2008
  • The creation of a single European rail transport market it is important to increase confidence between the actors on the market and between member states who shall ensure that railway safety is generally maintained and, where reasonably practicable, continuously improved. For this purpose the European railway safety directive introduces a mechanism to adopt a Common Safety Targets (CST) expressed in risk acceptance criteria for individuals and for society. This paper focuses on the apportionment of safety targets for European railway system. We develop a generic approach based on the Functional Hazard Analysis (FHA), to analyse the safety of railway systems for a unified European network and to comply with the CSTs required by the European railway Safety Directive. We suggest to combine the FHA technique with the functional railway architecture to allocate the safety targets to the railway functions.

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Estimation of structural dynamic characteristics of the Egyptian Obelisk of Theodosius

  • Saygili, Ozden
    • Earthquakes and Structures
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    • v.16 no.3
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    • pp.311-320
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    • 2019
  • Obelisks are historical monuments. There are several obelisks dating from ancient Egyptian period, located around various parts of the world. The city of Istanbul is a home to the Obelisk of Theodosius at the Hippodrome. Due to the expectation of a large event in the near future, the evaluation of seismic response of the Obelisk gets importance. Therefore, in this study structural dynamic behavior of the Obelisk was investigated using discrete element approach. Nonlinear dynamic analyses were performed using real and synthetic time series. Real and synthetic ground motions analyzed from this study seems consistent with the earthquake hazard levels that would be expected at the site of the Obelisk in the occurrence of an event of moment magnitude above 7.0 near Istanbul. Results are evaluated in terms of variation of displacement, relative displacement of adjacent blocks, normal stress and shear stress in time.

Risk Assessment for Heavy Metals in Soil, Ground Water, Rice Grain nearby Abandoned Mine Areas (국내 폐금속 광산지역에서의 토양, 지하수, 쌀의 중금속 노출에 따른 인체 위해성평가)

  • Na, Eun-Shik;Lee, Yong-Jae;Ko, Kwang-Yong;Chung, Doug-Young;Lee, Kyu-Seung
    • Korean Journal of Environmental Agriculture
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    • v.32 no.4
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    • pp.245-251
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    • 2013
  • BACKGROUND: The objectives of this study are to investigate the contamination levels of heavy metals in soil, ground water, and agricultural product near the abandoned Boeun and Sanggok mine areas in Korea and to assess the health risk for these local residents exposed to the toxic heavy metals based on analytical data. METHODS AND RESULTS: By the results of human health risk assessment for local residents around Boeun and Sanggok, human exposure to cadmium, copper, arsenic from soil and to lead, cadmium, and arsenic from rice grain were higher in Sanggok, but human exposure to zinc and arsenic from ground water was higher in Boeun. By the results of hazard index (HI) evaluation for arsenic, cadmium, copper, lead, and zinc, HI values in both areas were higher than 1.0. This result indicated that the toxicity hazard through the continuous exposure to lead, cadmium, arsenic from rice, ground water, and soil would be likely to occur to the residents in the areas. Cancer risk assessment for arsenic, risks from the rice were exposed to one to two out of 10,000 people in Boeun and one of 1,000 people in Sanggok. These results showed that the cancer risks of arsenic in both areas were 10~100 times greater than the acceptable cancer risk range of US EPA ($1{\times}10^{-6}{\sim}1{\times}10^{-5}$). CONCLUSION(S): Therefore, if these two local residents consume continuously with arsenic contaminated soil, ground water, and rice, the adverse health effects (carcinogenic potential) would be more increased.

Hazards Caused by UV Rays of Xenon Light Based High Performance Solar Simulators

  • Dibowski, Gerd;Esser, Kai
    • Safety and Health at Work
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    • v.8 no.3
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    • pp.237-245
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    • 2017
  • Background: Solar furnaces are used worldwide to conduct experiments to demonstrate the feasibility of solar-chemical processes with the aid of concentrated sunlight, or to qualify high temperature-resistant components. In recent years, high-flux solar simulators (HFSSs) based on short-arc xenon lamps are more frequently used. The emitted spectrum is very similar to natural sunlight but with dangerous portions of ultraviolet light as well. Due to special benefits of solar simulators the increase of construction activity for HFSS can be observed worldwide. Hence, it is quite important to protect employees against serious injuries caused by ultraviolet radiation (UVR) in a range of 100 nm to 400 nm. Methods: The UV measurements were made at the German Aerospace Center (DLR), Cologne and Paul-Scherrer-Institute (PSI), Switzerland, during normal operations of the HFSS, with a high-precision UV-A/B radiometer using different experiment setups at different power levels. Thus, the measurement results represent UV emissions which are typical when operating a HFSS. Therefore, the biological effects on people exposed to UVR was investigated systematically to identify the existing hazard potential. Results: It should be noted that the permissible workplace exposure limits for UV emissions significantly exceeded after a few seconds. One critical value was strongly exceeded by a factor of 770. Conclusion: The prevention of emissions must first and foremost be carried out by structural measures. Furthermore, unambiguous protocols have to be defined and compliance must be monitored. For short-term activities in the hazard area, measures for the protection of eyes and skin must be taken.

Biological Hazard of Electromagnetic Field Exposure: A Review (전자기파의 생체 위해성에 관한 소고)

  • Jung, Kyung-Ah;Gye, Myung-Chan
    • Korean Journal of Environmental Biology
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    • v.29 no.4
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    • pp.241-250
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    • 2011
  • The safety of human exposure to an ever-increasing number and diversity of electromagnetic field (EMF) sources both at work and at home has clearly become a public health issue. To date many $in$ $vivo$ and $in$ $vitro$ studies revealed that EMF exposure can alter cellular metabolism, endocrine function, immune activity, reproductive function, and fetal development in animal system. The major parameters found to be altered in cells or individuals following EMF exposure include an increase of free radicals, DNA damage, cancer risk, developmental defect, and reproductive dysfunctions. Epidemiological studies reported EMF can increase life-threatening illnesses such as leukemia, brain cancer, amyotrophic lateral sclerosis, clinical depression, suicide, and Alzheimer's disease has been identified. These effects of EMF exposure differ according to duration of exposure, frequency of waves, and strength (energy) of EMF. In the present review, we briefly introduced the physical properties of EMF and summarized the effect of EMF on human and wildlife animals according to types of EMF, duration of exposure at cellular and organism levels.

Life Risk Assessment of Landslide Disaster Using Spatial Prediction Model (공간 예측 모델을 이용한 산사태 재해의 인명 위험평가)

  • Jang, Dong-Ho;Chung, C.F.
    • Journal of Environmental Impact Assessment
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    • v.15 no.6
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    • pp.373-383
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    • 2006
  • The spatial mapping of risk is very useful data in planning for disaster preparedness. This research presents a methodology for making the landslide life risk map in the Boeun area which had considerable landslide damage following heavy rain in August, 1998. We have developed a three-stage procedure in spatial data analysis not only to estimate the probability of the occurrence of the natural hazardous events but also to evaluate the uncertainty of the estimators of that probability. The three-stage procedure consists of: (i)construction of a hazard prediction map of "future" hazardous events; (ii) validation of prediction results and estimation of the probability of occurrence for each predicted hazard level; and (iii) generation of risk maps with the introduction of human life factors representing assumed or established vulnerability levels by combining the prediction map in the first stage and the estimated probabilities in the second stage with human life data. The significance of the landslide susceptibility map was evaluated by computing a prediction rate curve. It is used that the Bayesian prediction model and the case study results (the landslide susceptibility map and prediction rate curve) can be prepared for prevention of future landslide life risk map. Data from the Bayesian model-based landslide susceptibility map and prediction ratio curves were used together with human rife data to draft future landslide life risk maps. Results reveal that individual pixels had low risks, but the total risk death toll was estimated at 3.14 people. In particular, the dangerous areas involving an estimated 1/100 people were shown to have the highest risk among all research-target areas. Three people were killed in this area when landslides occurred in 1998. Thus, this risk map can deliver factual damage situation prediction to policy decision-makers, and subsequently can be used as useful data in preventing disasters. In particular, drafting of maps on landslide risk in various steps will enable one to forecast the occurrence of disasters.

Application of a Two-dimensional Flood Inundation Model based on Quadtree Grid (사면구조 격자 기법에 의한 2차원 홍수범람모형의 적용)

  • Kim, Jong-Ho;Lee, Seung-Oh;Yoon, Kwang-Seok;Cho, Yong-Sik
    • Journal of the Korean Society of Hazard Mitigation
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    • v.8 no.3
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    • pp.129-136
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    • 2008
  • All measures to cope with flooding rely on flood predictions to some extent. To investigate these predictions such as maximum water level or inundation area, a numerical model has been developed. The governing equations of the model are the two-dimensional Saint-Venant equations. The governing equations are discretized explicitly by using the leap-frog scheme and upwind scheme based on quadtree grids. The predicted numerical results have been verified by comparing to those of a Thacker problem. As a result of verifications, the present model is not only nearly four times as efficient as uniform grids but also in close agreement with the previous models. Next, the developed model is applied to several flood events in the Uiryeong basin. A general tendency is found that as a frequency is increasing, overall water levels including peak water level are increasing. At only a 500 year frequency, maximum water level is higher than 18.5 m. Therefore, it can be predictable that inundation will be generated in a 500 year frequency.

Effect of Comprehensive Breast Care on Breast Cancer Outcomes: A Community Hospital Based Study from Mumbai, India

  • Gadgil, Anita;Roy, Nobhojit;Sankaranarayanan, Rengaswamy;Muwonge, Richard;Sauvaget, Catherine
    • Asian Pacific Journal of Cancer Prevention
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    • v.13 no.4
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    • pp.1105-1109
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    • 2012
  • Breast cancer is the second most common cancer in women in India and the disease burden is increasing annually. The lack of awareness initiatives, structured screening, and affordable treatment facilities continue to result in poor survival. We present a breast cancer survival scenario, in urban population in India, where standardised care is distributed equitably and free of charge through an employees' healthcare scheme. We studied 99 patients who were treated at our hospital during the period 2005 to 2010 and our follow-up rates were 95.95%. Patients received evidence-based standardised care in line with the tertiary cancer centre in Mumbai. One-, three- and five-year survival rates were calculated using Kaplan-Meier method. Socio-demographic, reproductive and tumor factors, relevant to survival, were analysed. Mortality hazard ratios (HR) were calculated using Cox proportional hazard method. Survival in this series was compared to that in registries across India and discrepancies were discussed. Patients mean age was 56 years, mean tumor size was 3.2 cms, 85% of the tumors belonged to T1 and T2 stages, and 45% of the patients belonged to the composite stages I and IIA. Overall 5-year survival was 74.9%. Patients who presented with large-sized tumors (HR 3.06; 95% CI 0.4-9.0), higher composite stage (HR 1.91; 0.55-6.58) and undergone mastectomy (HR 2.94; 0.63-13.62) had a higher risk of mortality than women who had higher levels of education (HR 0.25; 0.05-1.16), although none of these results reached the significant statistical level. We observed 25% better survival compared to other Indian populations. Our results are comparable to those from the European Union and North America, owing to early presentation, equitable access to standardised free healthcare and complete follow-up ensured under the scheme. This emphasises that equitable and affordable delivery of standardised healthcare can translate into early presentation and better survival in India.

Prognostic Role of PTEN Gene Expression in Breast Cancer Patients from North-East Iran

  • Golmohammadi, Rahim;Rakhshani, Mohammad Hassan;Moslem, Ali Reza;Pejhan, Akbar
    • Asian Pacific Journal of Cancer Prevention
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    • v.17 no.9
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    • pp.4527-4531
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    • 2016
  • Background: PTEN protein is one of the most important tumour suppressor factors which is detectable by immunohistochemistry. The goal of the present study was to investigate the prognostic role of PTEN gene expression in breast cancer patients. Materials and Methods: This descriptive-analytical study was conducted on 100 breast cancer patients referred to Sabzevar hospitals in the north-east of Iran between 2010 and 2011, who were followed up to 2015. PTEN gene expression in tissue samples was determined using specific monoclonal antibodies and data were analyzed using Chi-square test and Fisher's exact test. Patient survival was analyzed after 4 years of follow-up using the Cox regression model. Results: PTEN gene expression was evident in 70 of 100 cnacer samples but was found at high levels in all non-cancer samples. There was an inverse significant relationship between PTEN gene expression and tumour stage or tumour grade (p<0.001). The expression of PTEN in invasive ductal tumours was lower than in non-invasive tumours. There was also an inverse significant relationship between the hazard of death and PTEN gene expression (p<0.001). In addition, there was an inverse significant relationship between tumour stage and hazard of death (p<0.001). Conclusion: These findings indicate that lack of PTEN gene expression can be a sign of a worse prognosis and poor survival in breast cancer cases.