• Journal of Life Science
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• v.31 no.10
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• pp.960-968
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• 2021

Since microalgae research started on late 18 century, they have been recognized as one of the most important bioresources used in bioindustry. Owing to the large efforts paid to industrial application of this microorganisms, their importance on food/feed and bioactive compounds has been further extending into the environmental research areas including alternative energy resources, mitigation of the carbon emission, and waste-water treatment. However, despite the importance on their industrial application, the fundamental research field related to the long-term preservation of microalgae culture has not received much attention. However, a less labor intensive and cost-efficient preservation technology enabling biologically active and stable microalgae-culture provides a key success factor in the biotechnological application. Therefore, this study investigated various cutting-edge microalgae cryopreservation technologies currently developed so far, mainly targeting Chlorophyta, which occupies the largest taxon in the classification system of microalgae. In addition, for the development of successful cryopreservation technique, the key factors such as temperature control effect and preservative effect during cryopreservation of microalgae culture were investigated. In addition, the problems with current preservation technology that is being used in Korean domestic biological resource banks and the international microalgal resource banks are described. According to our investigation, currently no standard method for long-term preservation of microalgae is available due to their various morphological and physiological characteristics. To overcome such issues, much more efforts on fundamental research area on the identification of specific biomarker used for microalgae taxonomical classification and further systemic approaches based on strain-specific cryopreservation methods needed.

• Korean Journal of Ecology and Environment
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• v.55 no.4
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• pp.398-405
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• 2022

The research was based on long-term studies on the major physico-chemical and hydrological factors and zooplankton community dynamics in the Hwang River. We had 341 times survey and collected zooplankton samples in the Hwang River of mid-Nakdong River from 1995 to 2013. We identified 97 zooplankton species, including 77 rotifers, 16 cladocerans, and 4 copepods. The total zooplankton abundance and species diversity were shown distinctive temporal variation (ANOVA, p<0.001). Annual average of zooplankton population density was 58.4±3.2 ind L^-1 (n=341) and the lowest was 17.0±3.8 ind L^-1 (1996, n=20), while the highest was 151.5±32.3 ind L^-1 (2010, n=22). For zooplankton, small rotifer groups(e.g., Keratella sp., Brachionus sp., Trichotria sp.) dominated the study site for 19 years survey. Statistical analysis revealed that there were positive relationships with SiO₂ (p=0.002) and water level (p<0.001) for the high abundance of rotifer community. There were considerable variations both the total cladocerans population and the number of cladocerans' species concerning annual precipitation. Despite the appearance of various zooplankton in the Hwang River, the mean population density remained low. Due to the lateral structures in the Nakdong River, the downstream basin of the Hwang River is inevitably affected. The zooplankton community in our study site is considered to be mainly influenced by external factors that can stably increase and maintain the volume of the water body and internal factors that induce an increase in food sources through the inflow of nutrients into the water body.

• Journal of Korea Entertainment Industry Association
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• v.13 no.7
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• pp.375-384
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• 2019

The purpose of this study was to investigate the effects of long-term aerobic dancing exercise on body composition, physical fitness and mental function in older women over 70 years old. All subjects were limited to older women aged 70 to under 85. The experimental group performed aerobic exercise of 2-3 times a week for 9.2 ± 4.6 yrs, and the control group did not perform any regular exercise and spent 3-4 times a week mainly in the relaxing facility for older. As a results in this study, the weight, muscle mass and body fat percentage of the aerobic group were not significantly different from those of the control group, but there were significantly positive effects of aerobic group in visceral fat mass, abdominal obesity rate(%), body water content and systolic blood pressure(p < .05). In terms of physical fitness, Sit & reach, one-legged stand (right) and TUG of the aerobic group were significantly higher than those of the control group(p < .05), but there were no significant differences between two groups in the shoulder flexibilities and grip strength. MMSE as a cognitive function was not significantly different between the two groups, but GDS was significantly lower in the aerobic group than in the control group(p < .05). According to the correlation analysis between all variables and MMSE and GDS, MMSE was significantly inversely correlated with height (r = -0.425)(p < .05), and no correlation was detected with other variables. However, GDS have signitively negative correlations with resting heart rate(r = -0.464), sit & reach(r = -0.525) left(r = -0.491) and right grip strengths(r = -0.635) as well as positive correlation systolic blood pressure(r = 0.482) and TUG (r = 0.479), respectively(p < .05). In conclusion, long-term aerobic exercise of elderly women over 70 older had positive effects on variables related to metabolic disease (visceral fat and resting heart rate), silver fitness variables related to falls, and depression level in the elderly.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.6 no.4
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• pp.153-171
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• 2011

The welfare system and the direction of the welfare policy have been unable to escape greatly from the frame of the past against the facts that the external environments of the national economy of the world including Korea have been changing in quick and rapid speed. Such results have caused the issues related with the welfare, economy and society ended in the ideological collision in connection with the goals of the policy, the right agreement between the policies lacked, and the intervention and conflict between the interest group concerning the policy continued. Social policy of Korea in the past had the level of complementing the parts which could not be solved through the growth. Employment creation had been achieved continuously backed up by the high rate of growth. And the low aging level, the young population structure, and the high rate of childbirth had been the structures that made such achievement possible. New economic, social and welfare environment at home and abroad has been requesting new change in welfare policy. Goal of the economic and social policy is to construct the safe economic and social system. And what has been requested has been the formation of the economic and social policy orienting the welfare nation in form of social investment and welfare expansion. Also the direction in strengthening the welfare system of Korea shall have the balance between the protection and activation strength with the necessity of converting to the prevention welfare from the post welfare. Also the public part, market, the 3rd sector and the share of the role of an individual shall be achieved. And what is needed is the achievement of the transfer from the paradigm of residual welfare to the universal welfare. And such improvements of the welfare system will be able to elevate the possible continuity of the system in long term basis through the improvement of the welfare system.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.43 no.3
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• pp.337-352
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• 2023

In general, Rainfall-Runoff model parameter set is optimized using the entire data to calculate unique parameter set. However, Korea has a large precipitation deviation according to the season, and it is expected to even worsen due to climate change. Therefore, the need for hydrological data considering seasonal characteristics. In this study, we conducted regional sensitivity analysis(RSA) using the conceptual Rainfall-Runoff model, GR4J aimed at the Soyanggang dam basin, and clustered combining the RSA results with hydrometeorological data using Self-Organizing map(SOM). In order to consider the climate characteristics in parameter estimation, the data was divided based on clustering, and a calibration approach of the Rainfall-Runoff model was developed by comparing the objective functions of the Global Optimization method. The performance of calibration was evaluated by statistical techniques. As a result, it was confirmed that the model performance during the Cold period(November~April) with a relatively low flow rate was improved. This is expected to improve the performance and predictability of the hydrological model for areas that have a large precipitation deviation such as Monsoon climate.

• 한국신재생에너지학회:학술대회논문집
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• 2006.11a
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• pp.352-355
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• 2006

As the stainless steel has good corrosion resistance, mechanical property and ease of manufacture, it has been studied as the candidate material of metallic bipolar plate for automotive PIMFC. But, metal is dissolved under fuel cell operating conditions Dissolved ions contaminate a membrane electrode assembly (MEA) and, decrease the fuel cell performance. In addition, metal oxide formation on the surface of stainless steel increases the contact resistance in the fuel cell. These problems have been acted as an obstacle in the application of stainless steel to bipolar plate. Therefore, many kinds of coating technologies have been examined in order to solve these problems. In this study, stainless steel was coated in order to achieve high conductivity and corrosion resistance by several methods. Contact resistance was measured by using a tensile tester and impedance analyzer Corrosion characteristics of coated stainless steel were examined by Tafel-extrapolation method from the polarization curves in a solution simulating the anodic and cathodic environment of PEMFC. Fuel cell performance was also evaluated by single cell test. We tested various coated metal bipolar plate and conventional and graphite were also tested as comparative samples. In the result, coated stainless steel bipolar plate exhibited better cell performance than graphite to bipolar plate.

• Journal of Conservation Science
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• v.17 s.17
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• pp.5-18
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• 2005

Rock materials of the Stone Lantern in the Gwanchoksa temple was composed of dark grey granodiorite. This Stone Lantern is partly structural distortion as S-shape, especially, rocks of the upper supports and under the roof materials were highly deterioration due to the surface exfoliation, and strong secondary contaminations owing to the discoloration by oxidation of inserted iron plates between the rock properties, and white grey to dark black contaminants along the rain path way. Rock surface of the Stone Lantern occurred as partly green patches because of coated by algae, lichen and moss. This biological problems are need for cleaning and treatments. The Stone Lantern have to be considered to conservation method that can reduce weathering factors with long-term monitoring about environmental change for structural stability, surface degradation and mechanical weathering. Materials of the Stone Lantern and basement rocks of the area are consisted of same petrogenetic granodiotite based on occurrences, petrological and geochemical characteristics.

• The Korean Journal of Applied Statistics
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• v.23 no.3
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• pp.457-469
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• 2010

The government real estate policy has repeatedly relaxed and reinforced controls under the mutually contradictory targets. Switching over the supporting policy after the IMF crisis to the regulating policy from 2003, the government housing policy began to generate ill effects due to various regulations. This stud carefully investigates and statistically tests the transmissions of variations in the housing prices between the metropolitan areas in the early stage of the preceding administration, under the effect of the supporting scheme, and those in the late stage, under the effect of the restricting scheme. The distinctive feature between the two periods is found to be much simplified interrelationships of the price variations in the latter period. Consolidated leading role of capital sphere, by concentrated economic strength, suggest the obvious imbalance between variations in the metropolis housing prices.

• KDI Journal of Economic Policy
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• v.13 no.3
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• pp.113-133
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• 1991

본고(本稿)는 국민생활수준(國民生活水準)에 영향을 주는 주요 거시(巨視) 및 미시지표(微視指標)의 국제비교를 통하여 우리나라가 추구해 온 개발전략(開發戰略)을 재조명(再照明)하고 우리의 현재좌표(現在座標)를 검토코자 집필되었다. 자료(資料)의 제한(制限), 국제비교(國際比較)에서 흔히 제기되는 평가(評價)의 문제 등에도 불구하고 국제비교분석(國際比較分析)은 유용한 수단(手段)이었으며 다음과 같은 정책적(政策的) 함의(含意)를 얻을 수 있었다. 지금까지 한국(韓國)이 추구한 개발정책(開發政策)의 역점(力點)은 대체적으로 경제성장(經濟成長)에 두어져 왔었다고 분석되고 있다. 이는 높은 경제성장률(經濟成長率)이나 1인당(人當) 소득(所得)의 지속적인 증가를 통하여 소비수준(消費水準)의 제고와 소비구조(消費構造)의 개선 등 국민생활수준(國民生活水準)의 향상으로 연결되고 있다. 더불어 소득분배(消費分配)를 위시하여 보건(保健), 영양지표(營養指標) 등 사회지표(社會指標) 측면에서도 개선되는 추이를 보이고 있는 것으로 평가된다. 이와 같은 개발정책(開發政策)의 성공적(成功的) 결실(結實)은 국민복지증진(國民福祉增進)에 크게 이바지한 것임에 틀림없으나 사회복지향상(社會福祉向上)을 위한 적극적인 노력은 미흡하였다. 지속적인 고도성장(高度成長)의 결과 국민생활향상(國民生活向上)을 위한 기본요건(基本要件)인 1인당(人當) 소득(所得)이 크게 증가되어 빈곤인구(貧困人口)가 꾸준히 줄어들고 있으나 생활(生活)을 둘러싸고 있는 경제(經濟) 사회적(社會的) 환경은 상대적으로 열악(劣惡)해지게 되었다. 앞으로도 산업화(産業化)와 도시화(都市化)가 계속될 전망임에 비추어 국민생활(國民生活)과 직접적으로 관련되는 생활여건(生活與件)의 개선(改善)에 대한 각별한 정책적(政策的) 배려(配慮)가 요청된다고 판단된다. 따라서 경제(經濟)의 안정적인 운영과 함께 국민생활수준(國民生活水準)의 내실(內實) 있는 향상을 기해 나가자면 고도성장(高度成長)이 준 부작용(副作用)을 극소화해 나가야 할 것이다. 삶의 질(質)에 대한 수용할 만한 국민적(國民的) 욕구(慾求)를 과감히 받아들여 사회개발(社會開發)에 돌려지는 공적지출(公的支出)을 꾸준히 늘려나가되 일본(日本)의 경험이 시사하는 것처럼 비용효과적(費用效果的)인 지출이 되도록 제도적 장치가 강구될 필요가 있을 것이다. 국민생활수준(國民生活水準)의 개선은 장기적(長期的)인 시각(視角)에서 비전과 일관성을 지니고 추진되어야 할 성질을 지니고 있기 때문이다.

• Journal of the Korean Society of Marine Environment & Safety
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• v.22 no.5
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• pp.444-453
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• 2016

In this study, I suggested 'Mission command' as the on-scene commander's leadership intended to save people's lives quickly and safely when occured marine accident. First, I considered the concepts and limitations, efforts to introduce and settle the mission command, discussed why the introduction of mission command for Korea Coast Guard, the scope and specific way when applied. Korea Coast Guard must apply the Mission command as the on-scene commander's leadership to achieve efficient rescue work at the scene of an accident, even for incidents that can-not be foreseen. However, mission command cannot be established overnight: long-term, systematic efforts to stably develop mission command at the organizational level are required. We will strive to apply mission command across all aspects of the system, including education, training, personnel, and procedures, equipping each component with the basic requirements for mission command.