• Korean Chemical Engineering Research
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• v.47 no.6
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• pp.775-780
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• 2009

The efficacy of nitrifying sludge existed in biological nutrient removal process was examined for possible removal of endocrine disrupting chemical(EDC) in the effluent of wastewater treatment plant. Some of ammonia oxidizing bacteria causes ammonia oxidation mediated by ammonia monooxygenase(AMO) activity, which has low substrate specificity resulting in cometablic degradation of several chemicals. In this study, the removal of three model EDCs such as bisphenol A(BPA), nonylphenol(NP) and dibutyl phthalate(DBP) was studied in batch cultures using nitrifying sludge, BOD-oxidizing sludge with low nitrifying activity, and sterilized sludge. Nitrifying sludge showed higher initial removal rates in all batches of three EDCs when it was fed with ammonium as an energy source. The acclimation time was required for the removal of EDCs in batches using BOD-oxidizing sludge or nitritefed nitrifying sludge. That retardation seemed to attribute to the slow growth of cells using the EDCs while ammonium-fed nitrifying sludge could degrade EDCs through simultaneous cooxidation with ammonia oxidation. Sterilized sludge was also tested under the same conditions in order to find the contribution of physical adsorption to the removal of EDCs. About 10~20% of initial EDCs dose was removed when using sterilized sludge. Thus the biological activity is likely to play major role for the degradation of BPA, NP, and DBP rather than the physical adsorption from wastewater.

• Journal of Korea Port Economic Association
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• v.36 no.2
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• pp.109-124
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• 2020

Using panel data on freight rates and ship prices in the dry freighter market from January 2015 to December 2019, this study investigates the characteristics of shipping industry fluctuations. The analysis aims at two aspects of academic contribution. First, this study analyzes the relationship between shipping indicators and ship price based on separate dry-bulk ships, while the previous research considered the overall shipping index and weighted average ship prices. Second, the VAR model for the causality test is extended to a heterogeneous mixed panel model capable of limiting coefficients. There is a peak estimated by removing the cross-correlation problem, which is mainly raised in panel data analysis, using bootstrap estimation and solving the problem of information loss due to differences in non-stationary data. An empirical investigation of the causal relationship between economic fluctuations and ship price shows that the effect on the ship price from the freight is significant at the 1% level. This implies that there is a one-way relationship with demand in the shipping industry rather than a bilateral relationship.

• Journal of the Korean Data and Information Science Society
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• v.24 no.6
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• pp.1385-1400
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• 2013

This paper discusses income replacement ratios of national pension, retirement pension and individual annuities in Korea. These ratios are useful indicators for the assessment of retirement income security of workers. This paper projects income replacement ratios, using the pension entry rate, decrement rates, and life tables of the National Statistical Office. The result of the actuarial projection is that the income replacement ratio of national pension is approximately 21.0 to 22.7%, that the income replacement ratio of retirement pension is about 5.8 to 9.7%, and that the income replacement ratio of an individual annuity is about 13.5 to 21.0%, respectively. The income replacement ratio by income varies due to the effects of income redistribution in national pension and retirement pension, but the income replacement ratio of an individual annuity is constant, regardless of income.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.6
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• pp.27-36
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• 2018

A significant amount of studies were performed on evaporation heat transfer and pressure drop in microfin tubes. Most studies, however, focused on the refrigerants used in air-conditioners or heat pumps, and very limited information is available on R-404A, which is used in low temperature refrigeration. In this study, the evaporation heat transfer and pressure drop characteristics of R-404A in a 9.5 mm O.D. microfin tube were investigated for the mass flux range from $80kg/m^2s$ and $200kg/m^2s$. A smooth tube of the same outer dimeter was also tested for comparison. The results showed that the heat transfer enhancement ratio of the microfin tube increased with increasing mass flux and the heat flux decreased. The relative contribution of the convective heat transfer and the heat flux on total heat transfer was attributed to the observed trend. The pressure drops of the microfin tube were slightly (maximum 28%) larger than those of the smooth tube. Existing correlations do not adequately predict the measured heat transfer coefficients of pressure drops, probably due to the test range of the present study, which is outside of the existing correlations.

• Proceedings of the Korean Society for Cognitive Science Conference
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• 2000.05a
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• pp.267-272
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• 2000

본 연구에서는 한국어의 사·피동문을 실어증 환자가 처리하는 양상에 대하여 살펴보았다. 한국어의 사·피동문은 용언에 파생접사가 붙어 이루어지는 경우와 '-게 하다'나 '-어 지다'와 같이 구문 변형으로 하여, 실어증 환자에게 실험을 하였다. 실험에 참여한 환자는 명칭성 실어증 환자, 이해성 실어증 환자, 표현성 실어증 환자, 전반성 실어증 환자로 구성되어 있다. 본 실험에서는 단어 채워 넣기 과제(word completion task)를 사용하였다. 명칭성 실어증 환자의 경우 피동에서는 처리 오류를 보이는 반면, 사동에는 아무런 문제도 보이지 않았다. 표현성 실어증 환자의 경우, <피동-비변형>에서 오류를 많이 보였다. 이를 통해 한국어의 사·피동은 영어와 달리 통사상의 문제가 아니라는 결론을 내릴 수 있다. 즉 이미 사·피동 접사에 의해 파생된 단어가 어휘부에 저장되어 있고, 각 단어의 논항 정보에 따라 문장이 생성되는 것이다. 표현성 실어증 환자가 피동의 비변형에서 지배적인 오류를 보이는 것은 피동의 비변형이 타동사로서 변형인 피동형에 비해 하나의 논항을 더 취하기 때문이다. 이해성 실어증 환자의 경우 사·피동 생성에 별 어려움을 보이지 않았다. 이는 이해성 실어증 환자가 개별 어휘의 논항 정보에 손실을 적게 입고 있음을 시사하는 결과이다. 본 연구에서는 서로 다른 유형을 보이는 환자들을 대상으로 한국어의 사·피동의 처리양상을 대조한 결과, 첫재 사·피동은 서로 다른 통사, 의미상의 처리 양상을 보이고 있고, 둘째 파생접사가 결합된 형태로 어휘부에 저장되어 있는 개별 사·피동사에 의해 형성되는 것임을 확인하였다.d CO2 quantity causes flame temperature to fall since at high strain retes diluent effect is prevailing and at low strain rates the products inhibits chain branching. It is also found that the contribution of NO production by N2O and NO2 mechanisms are negligible and that thermal mechanism is concentrate on only the reaction zone. As strain rate and CO2 quantity increase, NO production is remarkably augmented.our 10%를 대용한 것이 무첨가한 것보다 많이 단단해졌음을 알 수 있었다. 혼합중의 반죽의 조사형 전자현미경 관찰로 amarans flour로 대체한 gluten이 단단해졌음을 알수 있었다. 유화제 stearly 칼슘, 혹은 hemicellulase를 amarans 10% 대체한 밀가루에 첨가하면 확연히 비용적을 증대시킬 수 있다는 사실을 알 수 있었다. quinoa는 명아주과 Chenopodium에 속하고 페루, 볼리비아 등의 고산지에서 재배 되어지는 것을 시료로 사용하였다. quinoa 분말은 중량의 5-20%을 quinoa를 대체하고 더욱이 분말중량에 대하여 0-200ppm의 lipase를 lipid(밀가루의 2-3배)에 대하여 품질개량제로서 이용했다.

• Journal of Korean Society of Forest Science
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• v.77 no.2
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• pp.193-198
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• 1988

This study was carried out to investigate the influence of shading pretreatment and planting density on the periodic needle leaves growth in fresh and dry weight. 1. The fresh and dry weight growth of needle leaves per seedlings increased with light intensity and decreased with increase of density. The best growth of needle leaves in fresh weight and dry weight appeared during the period from May to June. 2. The contribution rates to the growth of fresh and dry weight of needle leaves were 1.9% and 5.1% in light intensity, 3.6% and 3.2% in density and 83.7% and 75.6% in growth period, respectively. 3. For the three factors, shading, density and growth period, all the interactions between any two factors, and among the three factors in the fresh and dry weight growth of leaves per plant were significant.

• Korean Journal of Microbiology
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• v.45 no.1
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• pp.32-40
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• 2009

To understand contribution of thermophilic microorganisms in decomposition of litter deposits on shore of lakes, we surveyed a lakeshore litter deposit for bacteria growing at $60^{\circ}C$. Ten thermophilic isolates were selected for in-depth characterization, based on their high capacity to degrade high molecular weight organic compounds. Based on phylogenetic analysis on their 16S rRNA gene sequences, all isolates were identified as Geobacillus. The optimal growth temperature and pH of the strains ranged $55{\sim}60^{\circ}C$ and 6.0${\sim}$8.0, respectively. Salinity was inhibitory to the growth of the isolates, showing marked decrease of growth rates at 3% salinity. Based on activities of hydrolytic enzymes and profiles of carbohydrate utilization (determined by API 50 CHB kit), three G. stearothermophilus strains showed patterns clearly distinctive from other isolates. Two G. kaustophilus strains also demonstrated distinctiveness in their metabolic pattern and ecological parameters. However, ecological and metabolic profiles of the other five isolates were more variable and showed some degree of digression from their phylogenetic classification. Therefore, it could be concluded that endospore-forming thermophilic bacteria in lakeshore litter deposits contribute to degradation of organic materials with diverse ecological niches while having successions similar to microbial flora in compost. We propose that the thermophilic isolates and/or their thermo-tolerant enzymes can be applied to industrial processes as appropriate mixtures.

• Asia-Pacific Journal of Business
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• v.6 no.2
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• pp.81-95
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• 2015

This study is an investigative study into the effects that the 'travel motivations' of participants on walking tourism has on their 'degree of satisfaction' by identifying tourist motivations for selecting walking tour among many types of tourism and their effects on hikers' degree of satisfaction. This study was conducted with hikers affiliated with 'walking on beautiful roads '-one of Busan's preliminary social enterprises- with a total of 176 copies used for a final effective sample. Data collected was analyzed using SPSS WIN 18.0 to conduct a frequency analysis of the sample. Along with exploratory factor analysis, Cronbach's ${\alpha}$ coefficient was used as an estimate of the validity and reliability of each factor. Multiple regression analysis was done for an analysis of travel motivations and their effects on satisfaction. The scale rates items in the questionnaire in the following categories: 'Motivations' for walking tours consist of 5 factors- vacation, soul-searching, social get-togethers, nature tour, community experience-with a total of 20 items. 'The degree of satisfaction' is made up of a factor with a total of 4 items. The results of the study are as follows: with respect to the hypothesis that motivations for walking tour would have a positive effect on the degree of satisfaction, test results show that 'motivations' have significant partial effects on the 'degree of satisfaction'. Motivations affect the degree of satisfaction in the order of nature tour and soul-searching except for experience and social get-togethers- an indication that participants on walking tours tend to travel for the attractiveness of nature, wanting time for reflection and meditation. As the first investigative study into participants in walking tours products offered by travel agencies, the study has the following implications for marketers: First, travel agencies selling walking tour products and government institutions concerned about the development of hiking trails need to discuss ways to make the most of natural resources as they are- rather than using development-oriented approaches. The study has its own limitation: it is that with the lack of domestic and international studies on walking tours, the study has not gained access to precedent studies on the subject so it has not established a systemic approach to the emerging type of tourism. Hopefully, this study will make a small contribution to its development.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.8
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• pp.673-683
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• 2016

The purpose of the NCS-based curriculum is to prepare students for practical competencies to perform tasks demanded by industries by applying nationally and industrially developed and certified NCS to the currently held curriculum. In order to achieve this academic goal, education institutions must dedicate their utmost efforts to train trainees to attain flexibility in rapidly changing industry environments and competitiveness to perform the various tasks demanded by industries. The 47th article of the Higher Education Law explains that the purpose of the College corresponds with that of the NCS-based curriculum because the contribution of national and social development is related to the development of an industry. The college purpose and the NCS-based curriculum require close collaboration and cooperation between industries and colleges. This thesis analyzes cases of industry and college cooperation, researches adequate cases that suit the purpose of the NCS-based curriculum and proposes an appropriate industrial-education cooperation model that suits college and NCS-based curriculum by analyzing the cooperation model held by highly acknowledged universities oversea. In addition, this paper proposes a process and guideline to establish the industrial-education cooperation model. The industrial-education cooperation model proposed herein not only practically aligns the NCS-based curriculum to fit the industry environments, but also supports each party in pursuing and achieving its goals through an effective cooperative structure. The NCS-based industrial education model is anticipated to improve colleges' employment rates, allow industries' procurement of brilliant human resources, and contribute to the development of domestic industries through effective college education and training competent professionals for society.

• Journal of Korean Society of Forest Science
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• v.65 no.1
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• pp.24-30
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• 1984

The average number of empty seeds per cone on the mature tree was $10.03{\pm}0.61$. The ratios of empty seeds to total seeds and to full seeds were $7.38{\pm}0.35%$ and $8.42{\pm}0.49%$, respectively in average. The number of empty seeds per cone and the ratios were varied with the site condition; fruited year, and individual tree. The contribution rates of these sources of variance to the number of empty seeds per cone were respectively 3.50%, 8.06%, and 55.41%. No correlationships were found between the amount of empty seeds in number or ratio and the cone production, and the D.B.H. of mother tree. However, both the number of empty seeds and the ratio of empty seeds to total seeds showed significant positive correlations with the number of 1-year-old cones per tree.