• Journal of Korea Foresty Energy
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• v.22 no.3
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• pp.29-36
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• 2003

This paper concerned the application of improvement in Vivo of Traditional Method for determination of nitrate reductase (NR) activity of leaves to dominant tree species in five forest communities of northern aspect of Changbai Mountain. The results indicated that the NR activity of tree species was related to shade tolerance, and the intolerant tree species had higher NR activity. The NR of a species was also related to the vertical structure and ecological site condition. The tree species, which have higher NR activities should be selected for fast growing and high yield tree species.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.10
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• pp.4908-4928
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• 2017

Recent research into wireless sensor network (WSN)-related technology that senses various data has recognized the need for spatio-temporal queries for searching necessary data from wireless sensor nodes. Answers to the queries are transmitted from sensor nodes, and for the efficient transmission of the sensed data to the application server, research on index processing methods that increase accuracy while reducing the energy consumption in the node and minimizing query delays has been conducted extensively. Previous research has emphasized the importance of accuracy and energy efficiency of the sensor node's routing process. In this study, we propose an itinerary-based R-tree (IR-tree) to solve the existing problems of spatial query processing methods such as efficient processing and expansion of the query to the spatio-temporal domain.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.8 no.6
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• pp.534-543
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• 2015

This paper proposes an Energy Theft Traceback Protocol(ETTP) based on Logging and Marking that can trace Energy Theft back in Smart Grid Environment. The ETTP consists of the following three phases. First, it classifies Energy Theft Type into Measurement Rejection and Data Fabrication by generating an Energy Theft Tree. Second, it detects an Energy Theft by using the Energy Theft Tree. Finally, it trace an Energy Theft back by using the Logging Table of a Router and the Marking Information of a Packet. The result of its simulation shows that the Detection Ratio of Energy Theft is estimated at 92% and the Success Ratio of Energy Theft Traceback at 93%. Therefore, the ETTP not only reduces such risk factors as Forgery and Tampering about Billing information but also provides safe and reliable Smart Grid environment.

• Journal of the Korean Society of Safety
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• v.15 no.2
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• pp.126-135
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• 2000

Probabilistic Safety Assessment (PSA) is an engineering analysis method to identify possible contributors to the risk from a nuclear power plant and now it has become a standard tool in safety evaluation of nuclear power plants. PSA consists of three phases named as Level 1, 2 and 3. Level 2 PSA, mainly focused in this paper, uses a step-wise approach. At first, plant damage states (PDSs) are defined from the Level 1 PSA results and they are quantified. Containment event tree (CET) is then constructed considering the physico-chemical phenomena in the containment. The quantification of CET can be assisted by a decomposition event tree (DET). Finally, source terms are quantitatively characterized by the containment failure mode. As the main benefit of PSA is to provide insights into plant design, performance and environmental impacts, including the identification of the dominant risk contributors and the comparison of options for reducing risk, this technique is expected to be applied to the industrial safety area.

• Journal of the Korean Society of Safety
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• v.32 no.3
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• pp.160-171
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• 2017

US national research laboratories developed the first Vital Area Identification (VAI) method for the physical protection of nuclear power plants that is based on Event Tree Analysis (ETA) and Fault Tree Analysis (FTA) techniques in 1970s. Then, Korea Atomic Energy Research Institute proposed advanced VAI method that takes advantage of fire and flooding Probabilistic Safety Assessment (PSA) results. In this study, in order to minimize the burden and difficulty of VAI, (1) a set of streamlined VAI rules were developed, and (2) this set of rules was applied to PSA fault tree and event tree at the initial stage of VAI process. This new rule-based VAI method is explained, and its efficiency and correctness are demonstrated throughout this paper. This new rule-based VAI method drastically reduces problem size by (1) performing PSA event tree simplification by applying VAI rules to the PSA event tree, (2) calculating preliminary prevention sets with event tree headings, (3) converting the shortest preliminary prevention set into a sabotage fault tree, and (4) performing usual VAI procedure. Since this new rule-based VAI method drastically reduces VAI problem size, it provides very quick and economical VAI procedure. In spite of an extremely reduced sabotage fault tree, this method generates identical vital areas to those by traditional VAI method. It is strongly recommended that this new rule-based VAI method be applied to the physical protection of nuclear power plants and other complex safety-critical systems such as chemical and military systems.

• Journal of the Korean Institute of Landscape Architecture
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• v.38 no.3
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• pp.23-32
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• 2010

The purpose of this study is to quantify human energy budgets for different structures of outdoor spatial surfaces affecting thermal comfort, to analyze the impacts of tree shading on building energy savings, and to suggest desirable strategies of urban greenspace planning concerned. Concrete paving and grass spaces without tree shading and compacted-sand spaces with tree shading were selected to reflect archetypal compositional types for outdoor spatial materials. The study then estimated human energy budgets in static activity for the 3 space types. Major determinants of energy budgets were the presence of shading and also the albedo and temperature of base surfaces. The energy budgets for concrete paving and grass spaces without tree shading were $284\;W/m^2$ and $226\;W/m^2$, respectively, and these space types were considerably poor in thermal comfort. Therefore, it is desirable to construct outdoor resting spaces with evapotranspirational shade trees and natural materials for the base plane. Building energy savings from tree shading for the case of Daegu in the southern region were quantified using computer modeling programs and compared with a previous study for Chuncheon in the middle region. Shade trees planted to the west of a building were most effective for annual savings of heating and cooling energy. Plantings of shade trees in the south should be avoided, because they increased heating energy use with cooling energy savings low in both climate regions. A large shade tree in the west and east saved cooling energy by 1~2% across building types and regions. Based on previous studies and these results, some strategies including indicators for urban greenspace planning were suggested to improve thermal comfort of outdoor spaces and to save energy use in indoor spaces. These included thermal comfort in construction materials for outdoor spaces, building energy savings through shading, evapotranspiration and windspeed mitigation by greenspaces, and greenspace areas and volume for air-temperature reductions. In addition, this study explored the application of the strategies to greenspace-related regulations to ensure their effectiveness.

• Proceedings of the Korean Nuclear Society Conference
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• 2004.05a
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• pp.229.2-229.2
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• 2004

• Proceedings of the Korean Nuclear Society Conference
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• 2005.05a
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• pp.789-790
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• 2005

• Proceedings of the Korean Nuclear Society Conference
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• 2005.05a
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• pp.1327-1328
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• 2005

• Proceedings of the Korean Nuclear Society Conference
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• 2005.10a
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• pp.1051-1052
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• 2005