• 한국화재소방학회논문지
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• 제13권4호
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• pp.1-6
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• 1999

본 연구에서는 위험물 취급설비에 대하여 4가지 화재유형으로 나누어 사고 시나리오를 작성하였다. 그리고 작성된 시나리오를 바탕으로 SuperChems Pro., 3.1, SAFER Trace Ver., 8.2, PHAST Pro., Ver., 5.2 등 외국의 사고결과 영향평가 프로그램을 이용하여 사고결과 영향평가 프로그램의 적용 특성을 분석·평가하였으며 이들 프로그램의 분석, 적용 평가 결과 및 관련이론을 활용하여 이를 전산화 할 수 있는 화재모델 및 서브모델을 선정하여 제시하였다.

• Journal of Radiation Protection and Research
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• 제41권4호
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• pp.368-372
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• 2016

Background: Methodologies for a series of radiological consequence assessments show a distinctive difference according to the design principles of the original nuclear suppliers and their technical standards to be imposed. This is due to the uncertainties of the accidental source term, radionuclide behavior in the environment, and subsequent radiological dose. Both types of PWR and PHWR are operated in Korea. However, technical standards for evaluating atmospheric dispersion have been enacted based on the U.S. NRC's positions regardless of the reactor types. For this reason, it might cause a controversy between the licensor and licensee of a nuclear power plant. Materials and Methods: It was modelled under the framework of the NRC Regulatory Guide 1.145 for light-water reactors, reflecting the features of heavy-water reactors as specified in the Canadian National Standard and the modelling features in MACCS2, such as atmospheric diffusion coefficient, ground deposition, surface roughness, radioactive plume depletion, and exposure from ground deposition. Results and Discussion: An integrated accident consequence assessment code, ACCESS (Accident Consequence Assessment Code for Evaluating Site Suitability), was developed by taking into account the unique regulatory positions for reactor types under the framework of the current Korean technical standards. Field tracer experiments and hand calculations have been carried out for validation and verification of the models. Conclusion: The modelling approaches of ACCESS and its features are introduced, and its applicative results for a hypothetical accidental scenario are comprehensively discussed. In an applicative study, the predicted results by the light-water reactor assessment model were higher than those by other models in terms of total doses.

• 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.

• 제어로봇시스템학회논문지
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• 제11권2호
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• pp.127-136
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• 2005

In this paper, a new architecture and comprehensive design methodology of genetically optimized Rule-based Fuzzy Polynomial Neural Networks(gRFPNN) are introduced and a series of numeric experiments are carried out. The architecture of the resulting gRFPNN results from asynergistic usage of the hybrid system generated by combining rule-based Fuzzy Neural Networks(FNN) with polynomial neural networks (PNN). FNN contributes to the formation of the premise part of the overall rule-based structure of the gRFPNN. The consequence part of the gRFPNN is designed using PNNs. At the premise part of the gRFPNN, FNN exploits fuzzy set based approach designed by using space partitioning in terms of individual variables and comes in two fuzzy inference forms: simplified and linear. As the consequence part of the gRFPNN, the development of the genetically optimized PNN dwells on two general optimization mechanism: the structural optimization is realized via GAs whereas in case of the parametric optimization we proceed with a standard least square method-based learning. To evaluate the performance of the gRFPNN, the models are experimented with the use of several representative numerical examples. A comparative analysis shows that the proposed gRFPNN are models with higher accuracy as well as more superb predictive capability than other intelligent models presented previously.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2005년도 추계종합학술대회
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• pp.557-560
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• 2005

The color of objects varies with changes in illuminant color and viewing conditions. As a consequence, color boundaries are influenced by a large variety of imaging variables such as shadows, highlights, illumination, and material changes. Therefore, invariant color models are useful for a large number of applications such as object recognitions, detections, and segmentations. In this paper, we propose invariant color models. These color models are independent of the object geometry, object pose, and illumination. From these color models, color invariant edges are derived. To show the validity of the proposed invariant color models, some examples are given.

• 산업경영시스템학회지
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• 제17권32호
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• pp.209-220
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• 1994

In this paper, we study the timing and equipment of replacement. Those affect both available possibility and technological levels of new equipments in the future. These problems are classified according to technological levels and in consequence generated four circumstance. Models are formulated in this research. These are able to make us decision which we replace equipment at the first time. A method is suggested to find the optimal age for replacement at given each circumstance. A solution procedure and numerical example are given.

• 한국대기환경학회지
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• 제15권5호
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• pp.687-696
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• 1999

Characteristics of four publicly-available accidental release models, ALOHA, SLAB, HGSYSTEM, and DEGADIS, are compared. These models are world-widely used and recently recommended by the Chemical Dispersion and Consequence Assessment(CDCA) Working Group of the United States as models applicable to generally broad safety-basis documentation applicatons. Four release scenarios are assumed by referring to the usage and storage conditions of toxic substances in the field as well as the USEPA model guideline(1993). Sensitivity of impact radius by varying meteorological conditions is tested in typical and worst-case meteorological conditions. The results show that ALOHA generally gives conservative estimates and the results from HGSYSTEM are sensitive to variations in meteorological conditions.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1991년도 한국자동제어학술회의논문집(국제학술편); KOEX, Seoul; 22-24 Oct. 1991
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• pp.1705-1711
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• 1991

On-line fault detection and diagnosis has an increasing interest in a chemical process industry, especially for a process control and automation. The chemical process needs an intelligent operation-aided workstation which can do such tasks as process monitoring, fault detection, fault diagnosis and action guidance in semiautomatic mode. These tasks can increase the performance of a process operation and give merits in economics, safety and reliability. Aiming these tasks, series of researches have been done in our lab. Main results from these researches are building appropriate knowledge representation models and a diagnosis mechanism for fault detection and diagnosis in a chemical process. The knowledge representation schemes developed in our previous research, the symptom tree model and the fault-consequence digraph, showed the effectiveness and the usefulness in a real-time application, of the process diagnosis, especially in large and complex plants. However in our previous approach, the diagnosis speed is its demerit in spite of its merits of high resolution, mainly due to using two knowledge models complementarily. In our current study, new knowledge representation scheme is developed which integrates the previous two knowledge models, the symptom tree and the fault-consequence digraph, into one. This new model is constructed using a material balance, energy balance, momentum balance and equipment constraints. Controller related constraints are included in this new model, which possesses merits of the two previous models. This new integrated model will be tested and verified by the real-time application in a BTX process or a crude unit process. The reliability and flexibility will be greatly enhanced compared to the previous model in spite of the low diagnosis speed. Nexpert Object for the expert system shell and SUN4 workstation for the hardware platform are used. TCP/IP for a communication protocol and interfacing to a dynamic simulator, SPEEDUP, for a dynamic data generation are being studied.

• 논리연구
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• 제17권1호
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• pp.71-109
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• 2014

셔어는 타르스키의 논리적 귀결 정의가 개념적으로나 외연적으로 적합한 설명이라고 믿는다. 셔어는 모스토프스키의 동형 구조 내의 불변적인 것으로서 일반화된 양화사 개념, 그리고 자신의 모형 이론에 근거해서 그 믿음을 정당화하려 하였다. 이 글에서 나는 타르스키의 정의를 정당화하려는 셔어의 시도는 반만 성공한 것임을 보이려 한다. 나는 논리적인 것이 동형 구조 내의 불변적인 것이라는 셔어의 생각은 논리적 귀결의 형식적 특징을 보이기에 충분하다는 점을 인정한다. 반면 나는 용어의 의미에 대한 셔어의 생각은 외연이 빈 술어의 문제를 제대로 다루기에는 아주 부적합해서, 결국 셔어는 논리적으로 필연적인 진리들과 그 밖의 진리들을 구별하는 데 실패하였다고 생각한다.

• Nuclear Engineering and Technology
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• 제50권8호
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• pp.1246-1254
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• 2018

The importance of performing Level 3 probabilistic safety assessments (PSA) along with a general interest in assessing multi-unit risk has been sharply increasing after the Fukushima Daiichi nuclear power plant (NPP) accident. However, relatively few studies on multi-unit Level 3 PSA have been performed to date, reflecting limited scenarios of multi-unit accidents with higher priority. The major difficulty to carry out a multi-unit Level 3 PSA lies in the exponentially increasing number of multi-unit accident combinations, as different source terms can be released from each NPP unit; indeed, building consequence models for the astronomical number of accident scenarios is simply impractical. In this study, a new approach has been developed that employs the look-up table method to cover every multi-unit accident scenario. Consequence results for each scenario can be found on the table, established with a practical amount of effort, and can be matched to the frequency of the scenario. Preliminary application to a six-unit NPP site was carried out, where it was found that the difference between full-coverage and cut-off cases could be considerably high and therefore influence the total risk. Additional studies should be performed to fine tune the details and overcome the limitations of the approach.