• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2018.10a
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• pp.467-469
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• 2018

Tactical wireless communications often suffer from communication problems such as channel interference and communication disconnection due to the variability of the network topology and poor communication environment. Therefore, it is very important to overcome the problem of communication failure of the wireless communication network caused by the poor tactical environment and to improve the survivability. This paper describes the automatic control methodology of wireless communication equipment to identify and distinguish the situation of communication failure without user intervention and to implement more effective solution.

• Journal of the Ergonomics Society of Korea
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• v.30 no.1
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• pp.203-211
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• 2011

Objective: The aim of this study is to introduce a methodology to assess driver's emotion stability by using bio-signals. Background: Psychophysiological analysis of driver's behavior has been conducted to improve the driving safety and comfort. However, the variability of bio-signal and individual difference made it difficult to assess the psychophysiological status of drivers that can be expressed as emotional stability of drivers. Method: Two experimental studies were reviewed and summarized. New techniques assessing emotional stability of drivers were explained. Statistical concept and multidimensional space were used to identify the emotionally stable conditions. Conclusion: Psychophysiological approach can provide information of driver's emotional status. The experimental methodology and algorithm used in this study showed the possibility of parameterization of psychophysiological response. Application: Currently measured statistical and geometrical data can be further applied to develop an interactive device monitoring and reacting driver's emotion when driver experiences emotionally unstable or uncomfortable situation.

• Journal of the Korea Furniture Society
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• v.18 no.3
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• pp.166-176
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• 2007

Thanks to the recent apartment housing sales in new cities and metropolitan area, the public-use furniture market is greatly animated with the development of customized furniture. Nevertheless, the situation becomes difficult because of the fierce competition among the furniture suppliers with quoting at the lower price to get the order. In order to produce unique and stylish living cabinets, it is required for the furniture designer to create the design under the systematic design process collaborated with the construction company and make the design proposal thereby to the construction company. The present paper is focused on the re-usability of TV set currently possessed by the tenant, variability, uniqueness, pricing level suitable for the cost of real estate sales, modern design and so on. in the development of apartment living room cabinet. Thus, it is important for the furniture supplier to realize the importance of the design field in order to enhance the competitiveness of the customized furniture in the apartment housing. Accordingly the present researcher has developed the modem variable living room cabinet in accordance with the systemic design process by realizing the leads of tenant of the apartment housing and then establishing the concept focused on the design required by both the tenant and construction company.

• Korean Journal of Agricultural and Forest Meteorology
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• v.1 no.1
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• pp.1-11
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• 1999

Rice yield and primary productivity (NPP) are dependent upon the variability of climate and soil. The variability and regionality of the rice yield and net primary productivity were evaluated with the meteorological data collected from Korea Meteorology Administration and the actual rice yield data from the Ministration of Agriculture and Forestry, Korea. The estimated NPP using the three models, dependent upon temperature(NPP-T), precipitation(NPP-P) and net radiation(NPP-R), ranged from 10.87 to 17.52 Mg ha$^{-1}$ with average of 14.69 Mg ha$^{-1}$ in the South Korea and was ranged 6.47 to 15.58 Mg ha$^{-1}$ with average of 12.59 Mg ha$^{-1}$ in the North Korea. The primary limiting factor of NPP in Korea was net radiation, and the secondary limiting factor was temperature. Spectral analysis on the long term change in air temperature in July and August showed periodicity. The short periodicity was 3 to 7 years and the long periodicity was 15 to 43 years. The coefficient of variances, CV, of the rice yield from 1989 to 1998 ranged 3.23 percents to 12.37 percents which were lower than past decades. The CV's in Kangwon and Kyeongbuk were high while that in Chonbuk was the lowest. The prediction model based on th e yield index and yield response to temperature obtain ed from the field crop situation showed reasonable results and thus the spatial distributions of rice yield and predicted yield could be expressed in the maps. The predicted yields was well fitted with the actual yield except Kyungbuk. For better prediction, modification should be made considering radiation factor in further development.

• Journal of Acupuncture Research
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• v.21 no.4
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• pp.135-147
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• 2004

Objective: Moxibustion is one of major healing technique in oriental medicine. It has been widely used in many disease. There is an text which suggest moxibustion is more efficient to the situation of han(寒) and heo(虛) than yeal(熱) and sil(實) in Huangdineijing <黃帝內經>. The aim of this study is to research the effect of moxibustion at Shinmun(H7) is different according to cold or heat tendendy man by analyzing the electroencephalogram(EEG). Methods: We classified objects by their cold or heat tendency using questionnare for cold - heat patternization. (12 cold tendency man, 19 heat tendency man) Before and after moxibustion at Shinmun(H7), EEG raw data were measured during 5 minutes. The correlation dimension(D2), the correlation dimension variability rate(${\Delta}D2$), largest lyapunov exponent(L1) and largest lyapunov exponent variability rate(${\Delta}L1$) were calculated. We analyzed D2, ${\Delta}D2$, L1, ${\Delta}L1$ to see the effect of moxibustion at Shinmun(H7) was statistically different according to Cold or Heat tendendy man. Results : Paired t-test showed significant differences between before and after moxibustion at Shinmun(H7) on the Fp2 in D2(p<0.05), on the Fp2, F3 and F4 in ${\Delta}L1$(p<0.05). Student Hest showed significant differences between cold and heat tendendy man on the F3 in ${\Delta}L1$(p<0.05). Conclusion: These results suggest that moxibustion at Shinmun has an effect on stabilizing mind and it is more efficient to the cold tendendy man than the heat tendendy man.

• Journal of Wetlands Research
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• v.13 no.1
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• pp.1-11
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• 2011

A chronic drought stress has been imposed during non-rainy season(from winter to spring) since 1990s. We faced the most significant water crisis in 2001, and the drought was characterized by sultry weather and severe drought on a national scale. It has been widely acknowledged that the drought related damage is 2-3 times serious than floods. In the list of the world's largest natural disaster compiled by NOAA, 4 of the top 5 disasters are droughts. And according to the analysis from the NDMC report, the drought has the highest annual average damage among all the disasters. There was a very serious impact on the economic such as rising consumer price during the 2001 spring drought in Korea. There has been flood prevention measures implemented at national-level but for mitigation of droughts, there are only plans aimed at emergency (short-term) restoration rather than the comprehensive preventive measures. In addition, there is a lack of a clear set of indicators to express drought situation objectively, and therefore it is important and urgent to begin a systematic study. In this study, a nonstationary downscaling model using RCM based climate change scenario was first applied to simulate precipitation, and the simulated precipitation data was used to derive Standardized Precipitation Index (SPI). The SPI under climate change was used to evaluate the spatio-temporal variability of drought through principal component analysis at three different time scales which are 2015, 2045 and 2075. It was found that spatio-temporal variability is likely to modulate with climate change.

• Korean Journal of Ecology and Environment
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• v.51 no.3
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• pp.205-211
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• 2018

In this study, we estimated the applicability of length-weight relationship-based biomass calculations by comparison of body length of genus Polyarthra collected from different habitats. Through the comparison, we also tested availability of representative species-specific biomass value of Polyarthra which is often used without length measurement. Polyarthra samples were collected from rivers (Han River and Nakdong River) and reservoir (Paldang Reservoir), and the body length was measured for statistical comparison among habitats and biomass calculations using different equations suggested previously. According to the results, the body length of Polyarthra spp. was significantly different among sampling sites, and the necessity of body length measurement for rotifer species in each situation has been suggested rather than using the representative biomass values which is fixed without considering time and space. Comparison of suggested biomass calculations based on our measured Polyarthra body length, the equation suggested by McCauley showed more reasonable range of biomass values than that suggested by EPA. In addition, in order to calculate more accurate biomass, it is necessary to measure the body length of rotifers, at least more than 44 individuals to reduce error probability to less than 5% with 99% probability. However, since direct measurement of rotifers biomass is limited, it is considered that further analyses are required for more precise application of rotifer biomass of which has high variability due to complex morphologies and species-specific cyclomorphosis often induced by biotic and abiotic factors in the habitats.

• Environmental and Resource Economics Review
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• v.33 no.2
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• pp.113-133
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• 2024

Variable renewable energy (VRE) such as solar and wind power is the main sources of achieving carbon net zero, but it undermines the stability of power supply due to high variability and uncertainty. Energy storage system (ESS) can not only reduce the curtailment of VRE by load shifting but also contribute to stable power system operation by providing ancillary services. This study analyzes how the allocation of ESS resources between load shifting and ancillary service can contribute to maximizing the efficiency of power supply in a situation where the problems caused by VRE are becoming more and more serious. A stochastic power system optimization model that can realistically simulate the variability and uncertainty of VRE was applied. The analysis time point was set to 2023 and 2036, and the optimal resource allocation strategy and benefits of ESS by varying VRE penetration levels were analyzed. The analysis results can be largely summarized into the following three. First, ESS provides excellent functions for both load shifting and ancillary service, and it was confirmed that the higher the reserve price, the more limited the load shifting and focused on providing reserve. Second, the curtailment of VRE can be a effective substitute for the required reserve, and the higher the reserve price level, the higher the curtailment of VRE and the lower the required amount of reserve. Third, if a reasonable reserve offer price reflecting the opportunity cost is applied, ESS can secure economic feasibility in the near future, and the higher the proportion of VRE, the greater the economic feasibility of ESS. This study suggests that cost-effective low-carbon transition in the power system is possible when the price signal is correctly designed so that power supply resources can be efficiently utilized.

• World Technopolis Review
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• v.8 no.1
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• pp.59-70
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• 2019

Where is a better place to live? In the coming era, this should be more than simply a livable place. It should be an adaptable place that has a flexible system adaptable to any new situation in terms of diversity. Customization and real-time operation are needed in order to realize this technologically. We expect a smart city to have a flexible system that applies technologies of self-monitoring and self-response, thereby being a promising city model towards being a better place to live. Energy demand and supply is a crucial issue concerning our expectations for the flexible system of a smart city because it is indispensable to comfortable living, especially city living. Although it may seem that energy diversification, such as the energy mix of a country, is a matter of overriding concern, the central point is the scale of place to build grids for realizing sustainable urban energy systems. A traditional hard energy path supported by huge centralized energy systems based on fossil and nuclear fuels on a national scale has already faced difficult problems, particularly in terms of energy flexibility/resilience. On the other hand, an alternative soft energy path consisting of small diversified energy systems based on renewable energy sources on a local scale has limitations regarding stability, variability, and supply potential despite the relatively light economic/technological burden that must be assumed to realize it. As another alternative, we can adopt a holonic path incorporating an alternative soft energy path with a traditional hard energy path complimentarily based on load management. This has a high affinity with the flexible system of a smart city. At a system level, the purpose of all of the paths mentioned above is not energy itself but the service it provides. If the expected energy service is fixed, the conclusive factor in choosing a more appropriate system is accessibility to the energy service. Accessibility refers to reliability and affordability; the former encompasses the level of energy self-sufficiency, and the latter encompasses the extent of energy saving. From this point of view, it seems that the small diversified energy systems of a soft energy path have a clear advantage over the huge centralized energy systems of a hard energy path. However, some insuperable limitations still remain, so it is reasonable to consider both energy systems continuing to coexist in a multiplexing energy system employing a holonic path to create and maintain reliable and affordable access to energy services that cover households'/enterprises' basic energy needs. If this is embodied in a smart city concept, this is nothing else but smart energy inclusion. In Japan, following the Fukushima nuclear accident in 2011, a trend towards small diversified energy systems of a soft energy path intensified in order to realize a nuclear-free society. As a result, the Government of Japan proclaimed in its Fifth Strategic Energy Plan that renewable energy must be the main source of power in Japan by 2050. Accordingly, Sony vowed that all the energy it uses would come from renewable sources by 2040. In this situation, it is expected that smart energy inclusion will be achieved by the Japanese version of a smart grid based on the concept of a minimum cost scheme and demand response.

• Journal of Korean Neurosurgical Society
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• v.30 no.1
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• pp.73-77
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• 2001

Object : To determine whether to use surgical or medical therapy in treatment of infectious intracranial aneurysms, we reviewed two recent cases of infectious intracranial aneurysms and others known previous reports of aforementioned cases. Hence, we attempted to compare the validity and effectiveness of surgical and medical treatment. Method : Recently, we treated two cases of ruptured infectious intracranial aneurysms. In former case, the aneurysm was located distal to the middle cerebral artery in a patient with mild mitral regurgitation of the heart. In latter case, the aneurysm was multiple with varying hemorrhage. The hemorrhage was located bilaterally and a moderate mitral regurgitation and infective endocarditis were accompanied in this patient. Result : Due to the large size of the intracranial hematoma, stable medical condition, and easy resectability, we treated the former patient surgically. And, because of successive hemorrhage by multiple aneurysmal rupture, and the risk of heart failure, we treated the latter patient medically with serial follow-up angiography. Both patients are at present in good health. Conclusion : Because of the variability in associated factors, such as the patient's health, the number of lesions, location, anatomy of the aneurysms and the causative organism, each patient's care must be individualized and tailored to the patient's particular clinical situation.