• Journal of the Korean Society for Marine Environment & Energy
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• v.13 no.2
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• pp.121-125
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• 2010

Carbon Capture and Storage (CCS) technology mitigates the emission amount of carbon dioxide into the atmosphere and can reduce green house effect which causes the climate change. Deep saline aquifer or obsolete oil/gas storage etc. in the marine geological structure are considered as the candidates for the storage. The injection and storage relating technology have been interested in the global society, however the adverse effect caused by leakage from the system failure. Even the safety level of the CCS is very high and there is almost no possibility to leak but, still the risk to marine ecosystem of the high concentrated carbon dioxide exposure is not verified. The present study introduces the system and environmental risk assessment methods. The feature, event and process approach can be a good starting point and we found the some possibility from the fault tree analysis for evaluation. From the FEP analysis, we drove the possible scenario which we need to concentrate on the construction and operation stages.

• Nuclear Engineering and Technology
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• v.24 no.1
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• pp.14-29
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• 1992

COMCAF, a computer code for the common-cause failure analysis, is developed to treat the common-cause failures in nuclear power plants. In the treatment of common-cause failures, the minimal cut sets of the system are obtained first without changing the fault-tree structure. The occurrence probabilities of the minimal cut sets are then calculated accounting for the common-cause failures among components in the same minimal cut set or in different minimal cut sets. The basic parameter model is used to model the common-cause failures between similar or identical components. For dissimilar components, the assumption of symmetry used in the basic parameter model is applied to the basic events affecting two or more components. The top event probability is evaluated using the inclusion-exclusion method. In addition to the common-cause failures of components in the same minimal cut sets, failures of components in the different minimal cut sets are also easily accounted for by this method. This study applied this common-cause failure analysis to the PWR auxiliary feedwater system. The results in the top event probability for the system are compared with those of no common-cause failures.

• Animal cells and systems
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• v.13 no.1
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• pp.71-78
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• 2009

To clarify the reproductive function of vibration signals in Hynobius, which has externally fertilized eggs, we quantitatively analyzed the body and tail undulations of male Korean salamanders (Hynobius leechii) in sixteen mating events. One large and one small male, and one female were used in each mating event. We analyzed behaviors recorded over a total of 3 hrs for each mating event; 2 hrs before and 1 hr after female's oviposition. Males touched females using their snouts or body trunk throughout the entire mating periods, but females touched males increasingly more after approximately 1 hr before oviposition. Males conducted body undulations more than 50 times per 10 minutes at a mean frequency of 0.64 Hz. Large males conducted more body undulations than small males, particularly on the tree twig where females attached their egg sacs. Males responded to other males' body undulation throughout the mating period by orienting their head towards, approaching, and touching the undulating male. Females only responded for about 10-20 min before ovipositing, and most responses were directed to the large male's body undulation. Males conducted tail undulations 3.0 times per 10 min at a mean frequency of 1.7 Hz and most tail undulations occurred after one male bit the other male. These results suggest that body undulations function in both male-female and male-male interactions, while tail undulations mainly functions in male-male competition. Also, male H. leechii appear to actively attract females, while females respond to the males only at times close to oviposition.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.9
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• pp.135-140
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• 2015

Web-services employ XML that is the well-formed structure as a de-facto standard to represent data. SOAP or REST is one of the representative web-services using XML based massage passing systems. The XML parser can be divided into event driven and DOM tree. A streaming parser as an event driven is widely used for high-speed parsing. Since the streaming parser processes XML documents in sequence, they have any limitation to improve system performance. In order to improve speed of streaming XML parser, we present multibyte based streaming XML hardware parser using the element analyzer instead of the state machine. Compared to other parsers, the proposed MStreXHP can achieve about 2.72 times improvement in the number of clock cycles to be consumed in comparison of characters and sustain about 7.8Gbps throughput. Therefore, our MStreXHP is desirable for the streaming XML hardware parser on high-performance systems.

• Journal of KIISE:Databases
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• v.32 no.6
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• pp.603-615
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• 2005

As recent business environments are changed and become complex, a more efficient and effective business process management are needed. This paper proposes a new approach to the automatic execution of business processes using Event-Condition-Action (ECA) rules that can be automatically triggered by an active database. First of all, we propose the concept of blocks that can classify process flows into several patterns. A block is a minimal unit that can specify the behaviors represented in a process model. An algorithm is developed to detect blocks from a process definition network and transform it into a hierarchical tree model. The behaviors in each block type are modeled using ACTA formalism. This provides a theoretical basis from which ECA rules are identified. The proposed ECA rule-based approach shows that it is possible to execute the workflow using the active capability of database without users' intervention.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.401-401
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• 2015

본 연구에서는 기타재배지(벚나무재배지)에서 발생하는 비점오염물질 유출 및 수질특성을 살펴보고자 2014년 5월부터 9월까지의 총 12회의 강우사상에 대해 유출특성을 분석하고 오염물질별 유량가중평균농도(Event Mean Concentration, EMC) 및 오염부하를 산정하였다. 모니터링 기간동안 2.6~95.8 mm의 강우가 발생하였으며, 조사된 총 12회의 event 중 단 2회 유출이 발생하였다. 강우강도는 0.33~5.28 mm/hr의 범위로 나타났으며, 선행무강우일수는 0.6~21.2일, 총 유출량은 $0.92{\sim}20.75m^3$, 유출율은 0.03~0.18의 범위로 나타났다. 강우모니터링 결과, EMC는 TOC 3.4~10.3 mg/L(평균 6.9 mg/L), BOD 6.3~6.9 mg/L(평균 6.6 mg/L), COD 22.0~28.8 mg/L(평균 25.4 mg/L), SS 101.8~962.8 mg/L(평균 532.3 mg/L), T-N 4.295~11.864 mg/L(평균 8.080 mg/L) 그리고 T-P 1.109~1.582 mg/L(평균 1.346 mg/L)의 범위로 나타났으며, 각 강우사상에 대한 단위면적당 오염부하는 TOC 0.08~0.58 kg/ha, BOD5 0.05~1.07kg/ha, CODMn 0.22~3.76 kg/ha, SS 0.77~164.4 kg/ha, T-N 0.090~0.734 kg/ha, T-P 0.008~0.270 kg/ha의 범위로 산정되었다. 벚나무재배지의 수질 항목간 Pearson 상관계수를 분석한 결과, 항목 중 $COD_{Mn}$가 다른 수질항목과 유의성을 갖고 높은 상관관계가 나타나 초기유출효과 분석을 위한 대표 수질항목으로 선정하였다. 벚나무재배지의 경우 초기유출 발생에 의한 오염부하의 급격한 증가는 나타나지 않았으며, 누적오염부하량비의 그래프에서는 대부분의 강우사상에서 기울기가 직선에 가깝게 나타났다. 기타재배지의 경우 대부분 투수지역으로 초기세척효과가 비교적 작은 것으로 나타났으며, 지속적으로 오염물질을 배출하는 특성을 보이는 것으로 분석되었다.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.34 no.5
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• pp.319-325
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• 2021

The 2011 East Japan Earthquake caused accidents at a number of nuclear power plants in Fukushima, highlighting the need for a study on the seismic safety of multiple NPP (Nuclear Power Plant) units. In the case of nuclear power plants built on a site that shows a similar seismic response, there is at least a correlation between the seismic damage of structures, systems, and components (SSCs) of nuclear power plants. In this study, a probabilistic seismic safety assessment was performed for the loss of essential power events of twin units. To derive an appropriate seismic damage correlation coefficient, a probabilistic seismic response analysis was performed. Using the external event mensuration system program, we analyzed the seismic fragility and seismic risk by composing a failure tree of multiple loss of essential power events. Additionally, a comparative analysis was performed considering the seismic damage correlation between SSCs as completely independent and completely dependent.

• Journal of the Korean Society of Safety
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• v.36 no.4
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• pp.12-19
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• 2021

This paper presents a safety assessment method for FTA-based induction heating systems; the failures and causes of electrical fire are first analyzed for each part and module qualitatively, and methods to manage high probabilities of failure and electrical fire are considered, thereby improving the reliability of the induction heating system. The cumulative importance value (ACC) of the minimal cut set is drawn by setting failure as the top event, and STACK and SMPS are observed to account for about 70% of the induction heating system failures. Thus, intensively managing the basic events contained in the minimal cut set of failures for STACK and SMPS is expected to provide effective and stable operation of the induction heating system. When electrical fire is set as the top event, the STACK percentage is 90%. Accordingly, the current IGBT is changed to a FET to increase the applied voltage and prevent induction heating system failure, and a heat sink plane is installed to prevent FET heating caused by switching, thereby preventing an electrical fire. By classifying the parts and modules of the induction heating system in detail and by applying FTA based on actual failure rates and relevant data, more practical and reasonable results may be expected. Hence, continuous research must be conducted to ensure safety when using induction heating systems.

• Korean Chemical Engineering Research
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• v.52 no.6
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• pp.750-754
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• 2014

Quantitative risk analysis has been performed for a pervaporation process for production of high test peroxide. Potential main accidents are explosion and fire caused by a decomposition reaction. As the target process has a laboratory scale, the consequence is considered to belong to Category 3. An event tree has been developed as a model for occurrence of a decomposition reaction in the target process. The probability functions of the accident causes have been established based on the frequency data of similar events. Using the constructed model, the failure rate has been calculated. The result indicates that additional safety devices are required in order to achieve an acceptable risk level, i.e. an accident frequency less than $10^{-4}/yr$. Therefore, a layer of protection analysis has been applied. As a result, it is suggested to introduce inherently safer design to avoid catalytic reaction, a safety instrumented function to prevent overheating, and a relief system that prevents explosion even if a decomposition reaction occurs. The proposed method is expected to contribute to developing safety management systems for various chemical processes including concentration of hydrogen peroxide.

• The Journal of the Korea Contents Association
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• v.7 no.9
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• pp.176-182
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• 2007

The natural treasure is not only a product of nature and but also a heritage we need to protect. Among natural treasures, because an animal and a plant have lives, one of them are sure to be disappeared. The natural treasure, Sok-ri mountain's Jungyeepoomsong is unique. It is the only alive tree which secure a government position. Currently the Jungyeepoomsong gets into difficulty because of natural disasters and insect attacks. In addition, it is in a critical condition of dying old since the age of the tree is over 600 years. The purpose of this paper is to investigate plans for tourism resources of the Jungyeepoomsong. Because the Jungyeepoomsong is a rare variety, it can be commercialized as a plant resource. Also, it can be used as the method of creating income for local residents. To achieve research objective, this paper proposes the plans of a lineage certification using a genetic analysis technology, a genealogical table control system utilizing purebred preservation and storytelling, a database construction between producers, sellers, and owners, a tourism event, a method of building Jungyeepoomsong's brand and preserving its value.