• Journal of the Ergonomics Society of Korea
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• v.18 no.2
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• pp.121-132
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• 1999

This paper investigates the methodology to develop a layout of the simulator for measuring and evaluating human sensibility. Since the simulator layout is different from general building layouts in that it is organized in order to communicate systematically between facilities, laboratories to evaluate human sensibility and equipments to support experiments in simulator, two approaches based on eigenvector and cut tree are applied to develop a simulator layout. Qualitative input data (relationship chart. space requirements for each laboratory and equipment) are obtained and transformed into quantitative data. The information obtained by two approaches provides several meaningful clues to generate the simulator layout. The simulator layout is presented based on the obtained information by two approaches. Extracted quantitative data by using eigenvector and cut tree are meaningful of generating the simulator layout.

• Journal of the Korean Wood Science and Technology
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• v.10 no.3
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• pp.196-196
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• 1982

There is a heavy stocked wood volume in the forest of Kang-Won Province compared with the other forests of Korean Provinces. It mainly, however, consists of non-productive and inferior hardwoods and shrubs which grows naturally. -This naturally grown hardwood forest should be cut and reforested with more economical confierous and diciduous tree species by artificial and natural regeneration under the positive government support. This study was carried out to survey the reasonable and economical utilization measures on harvesting wood products when existing hardwood forest should be cut primarily. This is the rust report on the resources and the classification of tree species by the uses of wood growing in the hardwood forest of Kang-Won Province. According to the investigation, 321 hardwood species are growing in this forest, and 141 species of them are extremely not suitable for wood production. The usable species as fuel wood was 180, and these are able to classify into the 22 groups by the uses of wood.

• The Journal of Sustainable Design and Educational Environment Research
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• v.2 no.1
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• pp.69-79
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• 2002

This paper investigates the methodology to develop a layout of the simulator for measuring and evaluating human sensibility. Since the simulator layout is different from general building layouts in that it is organized in order to communicate systematically between facilities, laboratories to evaluate human sensibility and equipments to support experiments in simulator, two approaches based on eigenvector and cut tree are support to develop a simulator layout. Qualitative input data (relationship chart, space requirements for each laboratory and equipment) are obtained and transformed into quantitative data. The information obtained by two approaches provides several meaningful clues to generate the simulator layout. The simulator layout is presented based on the obtained information by two approaches. Extracted quantitative data by using eigenvector and cut tree are meaningful of generating the simulator layout.

• Nuclear Engineering and Technology
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• v.44 no.4
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• pp.405-414
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• 2012

In this paper, we propose a reliability estimation method for DI&C systems. At the system level, a fault tree model is suggested and Boolean algebra is used to obtain the minimal cut sets. At the component level, an exponential distribution is used to model hardware failures, and Bayesian estimation is suggested to estimate the failure rate. Additionally, a binomial distribution is used to model software failures, and a recently developed software reliability estimation method is suggested to estimate the software failure rate. The overall system reliability is then estimated based on minimal cut sets, hardware failure rates and software failure rates.

• Journal of Environmental Impact Assessment
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• v.18 no.6
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• pp.359-366
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• 2009

CCS (Carbon Capture and Storage) is considered as the most promising interim solution to deal with the greenhouse gas such as $CO_2$ responsible for global warming. Even though carefully chosen geologic formations are known to contain stored gas for a long time period, there are potential risks of leakage. Up to now, applicable risk assessment procedures for the leakage of $CO_2$ are not available. This study presents a basis for risk analysis applicable to a complex geologic storage system. It starts with the classification of potential leakage pathways. Receptors and the leakage effect on them are identified and quantified. Then, a fault tree is constructed, which yields the minimum cut set (i.e., the most vulnerable leakage pathway) and quantifies the probability of the leakage risk through the cut set. The methodology will provide a tool for risk assessment in a CCS project. The outcomes of the assessment will not only ensure the safety of the CCS system but also offer a reliable and efficient monitoring plan.

• Nuclear Engineering and Technology
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• v.56 no.6
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• pp.2092-2098
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• 2024

Probabilistic safety assessment (PSA) plays a critical role in ensuring the safe operation of nuclear power plants. In PSA, event trees are developed to identify accident sequences that could lead to core damage. These event trees are then transformed into a core-damage fault tree, wherein the accident sequences are represented by usual and complemented logic gates representing failed and successful operations of safety systems, respectively. The core damage frequency (CDF) is estimated by calculating the minimal cut sets (MCSs) of the core-damage fault tree. Delete-term approximation (DTA) is commonly employed to approximately solve MCSs representing accident sequence logics from noncoherent core-damage fault trees. However, DTA can lead to an overestimation of CDF, particularly when fault trees contain many nonrare events. To address this issue, the present study introduces a new zero-suppressed ternary decision diagram (ZTDD) algorithm that averts the CDF overestimation caused by DTA. This ZTDD algorithm can optionally calculate MCSs with DTA or prime implicants (PIs) without any approximation from the core-damage fault tree. By calculating PIs, accurate CDF can be calculated. The present study provides a comprehensive explanation of the ZTDD structure, formula of the ZTDD algorithm, ZTDD minimization, probability calculation from ZTDD, strength of the ZTDD algorithm, and ZTDD application results. Results reveal that the ZTDD algorithm is a powerful tool that can quickly and accurately calculate CDF and drastically improve the safety of nuclear power plants.

• Applied Biological Chemistry
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• v.50 no.4
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• pp.245-252
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• 2007

FTA (fault tree analysis), an analytical method for system failure management, was employed in the management of faults in running PCR analysis. PCR is executed through several processes, in which the process of PCR machine operation was selected for the analysis by FTA. The reason for choosing the simplest process in the PCR analysis was to adopt it as a first trial to test a feasibility of the FTA approach. First, fault events-top event, intermediate event, basic events-were identified by survey on expert knowledge of PCR. Then those events were correlated deductively to build a fault tree in hierarchical structure. The fault tree was evaluated qualitatively and quantitatively, yielding minimal cut sets, structural importance, common cause vulnerability, simulation of probability of occurrence of top event, cut set importance, item importance and sensitivity. The top event was 'errors in the step of PCR machine operation in running PCR analysis'. The major intermediate events were 'failures in instrument' and 'errors in actions in experiment'. The basic events were four events, one event and one event based on human errors, instrument failure and energy source failure, respectively. Those events were combined with Boolean logic gates-AND or OR, constructing a fault tree. In the qualitative evaluation of the tree, the basic events-'errors in preparing the reaction mixture', 'errors in setting temperature and time of PCR machine', 'failure of electrical power during running PCR machine', 'errors in selecting adequate PCR machine'-proved the most critical in the occurrence of the fault of the top event. In the quantitative evaluation, the list of the critical events were not the same as that from the qualitative evaluation. It was because the probability value of PCR machine failure, not on the list above though, increased with used time, and the probability of the events of electricity failure and defective of PCR machine were given zero due to rare likelihood of the events in general. It was concluded that this feasibility study is worth being a means to introduce the novel technique, FTA, to the management of faults in running PCR analysis.

• Proceedings of the Korean Nuclear Society Conference
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• 2005.10a
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• pp.544-545
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• 2005

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.11a
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• pp.409-412
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• 1997

The phenomenon of water tree degradation of underground distribution power cables is taking place in polymeric insulation materials under the existence of water and application of electric stress, but water tree is not easy to observe, o water tree features in power cables are shown after cutting and dying with methyleneblue. In previous method, it is impossible to acquire continuous treeing data, and when the insulation material has been cut, the micro crack(water tree) has been damaged. In this paper, to overcome these deflects, the etching method is made use of making needle electrode about 170[${\mu}{\textrm}{m}$] diameter, and AgNO$_3$(silver nitrate) solution is used as liquid electrode to accelerate the growth of water trees. As a result of this study, water tree is observed in real-time with microscope. Electrical tree owing to water treeing is initiated at low electric field and grown with discontinuous. Namely, water tree is shown up a different characteristics of tree growth.

• Korean Journal of Plant Resources
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• v.14 no.3
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• pp.241-246
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• 2001

Effects of cutting media on shooting and seedling characteristics were investigated to determine productivity of seedling by root cuttings of lacquer tree. Shoots developed at 3 weeks after cut planting on PV (peat moss : Vermiculite : 1 : 1), PVS (peat moss : Vermiculite : Sand : 1 : 1 : 2) and PVSC (peat moss : Vermiculite : Sand : Clay loam : 1 : 1 : 2 : 2) media, and shooting rate was the highest in PVSC medium at 10 weeks after cut planting among the treatments. Shooting numbers per scion on PH and PVC media were 2.2 but those on HSC medium was 1.3, which was not significantly different among media. PVSC medium was suitable to use the root cuttings of lacquer tree as it meets the qualifications requirements. Seedlings on PVSC medium were excellent to transplant in field as tree height, branch number, leaf number, stem diameter and leaf area were good.