• Fire Science and Engineering
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• v.18 no.1
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• pp.54-66
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• 2004

In this article, we are to suggest the hazard-assessing method for the underground pipelines, and find out the pipeline-maintenance schemes of high efficiency in cost. Three kinds of methods are applied in order to refer to the approaching methods of listing the hazards for the underground pipelines: the first is RBI(Risk Based Inspection), which firstly assess the effect of the neighboring population, the dimension, thickness of pipe, and working time. It enables us to estimate quantitatively the risk exposure. The second is the scoring system which is based on the environmental factors of the buried pipelines. Last we quantify the frequency of the releases using the present THOMAS' theory. In this work, as a result of assessing the hazard of it using SPC scheme, the hazard score related to how the gas pipelines erodes indicate the numbers from 30 to 70, which means that the assessing criteria define well the relative hazards of actual pipelines. Therefore. even if one pipeline region is relatively low score, it can have the high frequency of leakage due to its longer length. The acceptable limit of the release frequency of pipeline shows 2.50E-2 to 1.00E-l/yr, from which we must take the appropriate actions to have the consequence to be less than the acceptable region. The prediction of total frequency using regression analysis shows the limit operating time of pipeline is the range of 11 to 13 years, which is well consistent with that of the actual pipeline. Concludingly, the hazard-listing scheme suggested in this research will be very effectively applied to maintaining the underground pipelines.

• Journal of Aerospace System Engineering
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• v.12 no.4
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• pp.1-8
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• 2018

The state of registry issues a type certificate validation (TCV) based on the satisfactory evidence that the product (aircraft, engine, and propeller) is in compliance with the appropriate airworthiness requirements. The Korean government performs an evaluation to determine whether the product complies with Korean airworthiness standards for issuing TCV according to the Korean aviation safety law. Recently, the Validation Principles Working Group (VPWG) has developed a risk-based model for validation of civil aeronautical products. Also, VPWG proposed to incorporate this validation model into the corresponding ICAO Standards and Recommended Practices and guidance material. In this paper, we have reviewed the validation model and discussed improvements in the validation process.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.25 no.2
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• pp.25-38
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• 2017

Current limitation of Aviation airworthiness manage system and text based Aviation safety report data, lack of Data Manage system for aviation parts failure and lack of continuing airworthiness related to task linking system for Inspection/Report/Improvement(AD ; Airworthiness Directive) have been apprehended to suggest direction of realizing improved operating system by applying aviation airworthiness manage system by using standardization and safety performance index based managing and safety performance index based data analyzing.

• Journal of the Korean Society of Mechanical Technology
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• v.13 no.2
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• pp.9-19
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• 2011

Most real world design evaluation and risk-based decision support combine quantitative and qualitative (linguistic) variables. Decision making based on conventional mathematics that combines qualitative and quantitative concepts always exhibit difficulty in modelling actual problems. The successful selection process for choosing a design/procurement proposal is based on a high degree of technical integrity, safety levels and low costs in construction, corrective measures, maintenance, operation, inspection and preventive measures. In this paper, a design decision support framework using a composite structure methodology grounded in approximate reasoning approach and evidential reasoning method is suggested for design evaluation of machinery space of a ship engine room at the initial stages. An illustrative example is used to demonstrate the application of the proposed framework.

• Journal of Energy Engineering
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• v.27 no.2
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• pp.1-13
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• 2018

The proportion of natural gas-fueled power generation is expanding due to the change of domestic energy policy pursuing reduction of dust and increasing clean energy consumption. Natural gas fuels used for the combined-cycle power plants and the district-heating power plants are operated at high temperature and high pressure in the fuel supply system. Accidents due to leakage of the gas such as fire and explosion should be prevented by applying risk management techniques. In this study, risk assessment was performed on the natural gas fuel supply system of a combined power plant based on the API RP 581 RBI code. For the application of the API RBI code, lines and segments of the evaluation target system were identified. Operational data and input information were analyzed for the calculations of probability of failure and consequence of failure. The results of the risk assessment were analyzed over time from the initial installation time. In the code-based evaluation, the gas fuel supply system was mainly affected by thinning, external damage, and mechanical fatigue damage mechanisms. As the operating time passes, the risk is expected to increase due to the external damage caused by the CUI(Corrosion Under Insulation).

• Proceedings of the Korean Society For Composite Materials Conference
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• 2000.11a
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• pp.245-248
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• 2000

Modern aircraft composite structures are designed using a damage tolerance philosophy. This design philosophy envisions sufficient strength and structural integrity of the aircraft to sustain major damage and to avoid catastrophic failure. The only reasonable way to treat on the same basis all the conditions and uncertainties participating in the design of damage tolerant composite aircraft structures is to use the probability-based approach. Therefore, the model has been developed to assess the probability of structural failure (POSF) and associated risk taking into account the random mechanical loads, random temperature-humidity conditions, conditions causing damages, as well as structural strength variations due to intrinsic strength scatter, manufacturing defects, operational damages, temperature-humidity conditions. The model enables engineers to establish the relationship between static/residual strength safety margins, production quality control requirements, in-service inspection resolution and criteria, and POSF. This make possible to estimate the cost associated with the mentioned factors and to use this cost as overall criterion. The methodology has been programmed into software.

• Journal of the Korean Institute of Gas
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• v.23 no.1
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• pp.62-69
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• 2019

The high pressure underground pipelines of industrial states such as Ulsan, Yeosu consist with not only the pipelines for the utility support such as Raw material of petrochemical industry and steam, but also high pressure pipelines of toxic, flammable gas intricately like a web. Therefore, in this study, based on in-depth comparison analysis of industrial estate pipelines, and underground city gas pipelines' safety management status, excavation frequency, excavation depth, patrol period which are pipe damage impact factor by the other construction are analyzed. And, as a result, risk changes and correlations due to risk reduction strategy of the other construction are compared to be presented the safety inspection operation model for the high pressure underground pipelines of industrial estates.

• Journal of The Korean Society of Agricultural Engineers
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• v.61 no.3
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• pp.101-112
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• 2019

This study developed selection criteria of small-scales reservoirs, having under $300,000m^3$ storage capacity, for the Emergency Action Plan(EAP) establishment in order to reduce the disaster risks of the reservoir's failures. Those reservoirs are out of ranges of Korean EAP establishment standard, but have potential risk of disasters as they have often failed by the recent extreme rainfall events and earthquakes, causing economical and life losses. The problem of reservoir aging is also one of the reasons of them. In this study, the developed selection criteria of small reservoirs for EAP establishment are storage capacity, embankment height, reservoir age, heavy rain factor and earthquake factor. These criteria were selected based on the review of the existing EAP establishment guidelines, analysis of the past dam failure cases, and the previous related studies. The quantification of these criteria were conducted for the practical applications in the fields, and applied to 67 previous failures in order to investigate the relation of each criteria with these failures. The earthquake factor found to be the highest relations followed by heavy rain factors, combination of earthquake and heavy rain factors, and reservoir age. The classification was made as observation and review groups for EAP establishments based on overlapping numbers of each criteria. This classifications applied to 354 reservoirs designated as having the potential disaster risk by MOIS, and showed 38.4% of observation and 11.9% of review groups. Anticipatory monitoring and regular inspection should be made by professional facility managers for the observation group, and necessity of EAP establishment should be assessed for the review group based on the downstream status and financial budget.

• Journal of the Korean Dietetic Association
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• v.22 no.4
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• pp.320-339
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• 2016

This study was conducted to identify risk factors to ensure food safety by evaluating cook supervisors' perceived performance of vegetable safety management at Korean food restaurants in Daegu. Recognition of the potential foodborne illness caused by vegetables was 2.60/5 on average. Inspection items with low scores by respondents during food safety inspection by government agencies were "Wash and sanitize vegetables" and "Keep washed and cut vegetables in the refrigerator". As for storage, perceived performance of "Store vegetable in the refrigerator less than 70% of the refrigerator capacity" scored less than 4 out of 5. About 86% of respondents answered "Water-only washing" for vegetable washing. For perceived performance of vegetable cooking, service, and leftover handling, 11 and three items out of 13 were significantly different depending on the size of restaurants and possession of culinary arts certificates, respectively. Based on results, it is necessary to provide food safety training programs for handling vegetables in order to increase knowledge of cook supervisors. In addition, intensive on-site guidance for safety management of vegetables is needed.

• Journal of Species Research
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• v.12 no.2
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• pp.189-196
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• 2023

We monitored the hitchhiker insect pests from the international vessels entering into Korea in 2021. As a result, total of 581 individuals were detected by the survey based on visual inspection with naked eye. Among them, 500 individuals were identified as 244 species of 65 families under 11 orders through the integrative taxonomic method with DNA barcoding and morphological reexamination, but the remaining 81 individuals were classified as only to the family level. Of the 244 species identified, 26 species were determined to be not-distributed species in Korea (two Orthoptera, two Hemiptera, one Megaloptera, five Coleoptera, three Hymenoptera, and 13 Lepidoptera). Among them, two species, Sagra femorata (Chrysomelidae, Coleoptera) and Dendrolimus punctatus (Lasiocampidae, Lepidoptera), were discovered as 'Regulated species' listed by Animal and Plant Quarantine Agency, South Korea. Therefore, we reported on the 26 not-distributed species in Korea and provided inanimate pathway information such as navigation routes on the vessels hitchhiking the species, state of the samples at the time of detection, identification results and original distribution for the detailed monitoring and the risk analysis on the species.