• Journal of Wetlands Research
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• v.20 no.2
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• pp.173-180
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• 2018

The utilization of TOC(Total organic carbon), a new environmental standard, was evaluated for 30 lakes in the Nakdong River Basin, which is used for drinking and agricultural usage. The active use of water resources begins with securing satisfactory water quality. Since this allows people and nature to maintain stability of quality, water quality standards are being tightened to ensure good water quality. In order to improve the pollution level of organic matter in lakes in the living environment, it is important to use the appropriate organic substance index. The relationship between the newly introduced TOC and the existing COD(Chemical oxygen demand) in the targeted lake was positively correlated with the possibility of replacing the TOC with COD. However, the environmental grade standard using TOC is better than the environmental grade standard using COD, so it has the same effect as that of the grade of water quality using TOC as an organic substance factor. This indicates the limitation of TOC to directly replace existing COD when trying to determine or improve the quality level using organic indicators of lakes. Therefore, in order to secure the qualitative safety of the lake, it is required to strengthen environmental standards of TOC in terms of water quality grade. In addition, the correlation between TOC and COD shows a great difference depending on the utilization characteristics of the lake. This requires clear scientific identification, and it requires continuous monitoring of COD that has been used to accumulate indicators of lake organic matter.

• Journal of Environmental Impact Assessment
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• v.24 no.2
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• pp.175-189
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• 2015

The objective of this study was to analyze characteristics of distribution of amphibian species and the affecting ecological factors. For the study, habitat environment factors were determined and applied to a habitat suitability model for the data collected from the Seom River in Hoengseong County and Wonju City, Gangwon Province, Korea between March 2013 to October 2013. The analyzed amphibian species were Rana nigromaculata, Hyla japonica, Rana dybowski, and Rana rugosa Temminck and Schlegel, and a logistic regression model was used with the pseudo-absence data. The result of the model analysis suggests that the major factors for Rana nigromaculata are distance to vegetation and rock and that for Hyla japonica is waterway. Rana dybowski and Rana rugosa Temminck and Schlegel have similar habitat characteristics, but the latter is shown to be dominant due to its wider habitat preference. According to the species richness model, the analyzed amphibian species are shown to have tendency to move between valleys or streams. This study quantitatively analyzed habitat environment characteristics using species distribution model, however, there is a limitation in terms of analysis on food factor and connectivity with other species. Combined with additional density or habitat analysis on birds or fish, this study can lead to more comprehensive analysis on biological environment factors.

• Korean Journal of Agricultural and Forest Meteorology
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• v.1 no.2
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• pp.160-164
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• 1999

Subsurface environments, including the intermediate vadose zone and aquifers, may be contributing to increased atmospheric concentrations of $N_2$O. Denitrification appears to be the major source of $N_2$O in the subsurface environment. In the intermediate vadose zone, the level of denitrifying activity is dependent on the soil morphology, particularly stratified layers within the soil profile, which impede water and solute movement and create conditions favorable for denitrification. Movement of organic C from the soil surface appears to support denitrifying activity by providing an energy source and increasing the consumption of $O_2$. Denitrirication and $N_2$O production have been observed in aquifers but appear to be of greatest significance in shallow unconfined aquifers. The lack of organic C, N $O_2$, or anaerobiosis is often a limiting factor for activity but seems to be site specific. The presence of denitrifying bacteria does not appear to be a major limitation, based on published results, but the ubiquity of denitrifiers in subsurface environments needs to be confirmed. The fate of the $N_2$O produced in subsurface environments is unknown. Transport of $N_2$O by up ward diffusion, by outgassing at contacts with surface waters, and by ground water use need to be quantified to determine the contribution to atmospheric $N_2$O. Contamination of subsurface environment with N $O_3$$^{ }$ and organics has the potential for increasing the contribution to atmospheric $N_2$O by enhancing denitrification .

• The Journal of Korean Medicine
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• v.33 no.3
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• pp.1-9
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• 2012

Objectives: This research was aimed 1) to find out various subjective symptoms cancer patients had, 2) to find out the quantitative difference of symptoms occurring according to the area of cancer, current treatment methods, and relapse of the cancer and 3) to analyze the relationship between the occurrence of symptoms. Methods: This study was a survey about the various subjective symptoms cancer patients had. The subjects were 48 cancer patients in a double-blinded randomized controlled trial about the effectiveness of Korean Red Ginseng (KRG) treatments. Surveys were examined before Korean Red Ginseng (KRG) treatments. The questionnaire consisted of demographic research, patient history and accompanying symptoms. The symptoms part consisted of 4 questions on general symptoms (vertigo, hot flush, rash, insomnia), 2 questions on digestion symptoms (anorexia, dyspepsia), 2 questions on excretions (diarrhea, constipation), and 5 questions on symptoms in different body parts (headache, dryness of lips, chest pain, aphthous ulcer, nose bleeding). The questionnaire was used to research presence of symptoms and relationships between the occurrence of symptoms. Results: A total of 48 patients took part in this survey. Dizziness was the most frequent subjective symptom patients had (64.58%), followed by dry mouth (43.75%), headache (43.75%), insomnia (41.67%), anorexia (37.5%) and chest discomfort (37.5%). The presence of these subjective symptoms was partially related to the patient's history details - type of cancer, method of cancer treatment (chemotherapy, radiotherapy), termination of treatment, presence of pain, fatigue and recurrence, etc. Factor analysis was conducted to analyze the relationship between the occurrence of symptoms. It suggested 5 factors as a result, but there was a limitation that only a low level of correlation was shown among them. Conclusions: We were able to analyze the occurrences and the relationships among them for accompanying subjective symptoms in cancer patients. However the results of the study are limited in that only 48 patients participated. The symptoms in cancer patients showed a tendency for clustering, occurring simultaneously or continuously rather than occurring alone. The study of these symptom clusters is worth further study, for it is similar to the Symptom Differentiation System in Traditional Korean Medicine. For effective approach to the treatment of cancer in Traditional Korean Medicine, further research on the Korean traditional view of cancer patients should be done based on this research, regarding various symptoms and those relationships on a larger scale.

• Journal of Korea Society of Industrial Information Systems
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• v.23 no.5
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• pp.77-87
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• 2018

The Purpose of This study is amid competition, High-quality human resources in food service industry make a lot of efforts. Especially, Work and Life Balance(WLB) is a considerable factor when modern workers decide and maintain the workplace and also it could be supposed as one strategic method that corporations could attract and maintain talented people. This study built a exploratory model that there is causal relationship of WLB(work and life balance) to employee's organizational commitment. Additionally this study examine the Moderating Effect of perceived value of work between WLB(work and life balance) and organizational commitment. This study utilized total 217 responses from workers of food service industrial employees and as analysis methods, it used descriptive statistic analysis, correlation analysis, multiple regression analysis, and hierarchical analysis. Results of analysis are as follows. First this study found that the work-life balance could give significant effects to the organizational commitment. work-growth balance and work-leisure balance has positive significance effect with the organizational commitment but work-family balance was not statistically significant. Second, The significance of this study indicates that perceived value of work plays a role as moderating variable influencing the relationship between work and growth balance and employee organizational commitment. Lastly, this study suggested the implication of the result, the limitation and the direction of future study. The results of this study provide suggestion to the company.

• Proceedings of the Materials Research Society of Korea Conference
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• 2012.05a
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• pp.65-65
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• 2012

Copper zinc tin sulfide ($Cu_2ZnSnS_4$, CZTS) is a very promising material as a low cost absorber alternative to other chalcopyrite-type semiconductors based on Ga or In because of the abundant and economical elements. In addition, CZTS has a band-gap energy of 1.4~1.5eV and large absorption coefficient over ${\sim}10^4cm^{-1}$, which is similar to those of $Cu(In,Ga)Se_2$(CIGS) regarded as one of the most successful absorber materials for high efficient solar cell. Most previous works on the fabrication of CZTS thin films were based on the vacuum deposition such as thermal evaporation and RF magnetron sputtering. Although the vacuum deposition has been widely adopted, it is quite expensive and complicated. In this regard, the solution processes such as sol-gel method, nanocrystal dispersion and hybrid slurry method have been developed for easy and cost-effective fabrication of CZTS film. Among these methods, the hybrid slurry method is favorable to make high crystalline and dense absorber layer. However, this method has the demerit using the toxic and explosive hydrazine solvent, which has severe limitation for common use. With these considerations, it is highly desirable to develop a robust, easily scalable and relatively safe solution-based process for the fabrication of a high quality CZTS absorber layer. Here, we demonstrate the fabrication of a high quality CZTS absorber layer with a thickness of 1.5~2.0 ${\mu}m$ and micrometer-scaled grains using two different non-vacuum approaches. The first solution-processing approach includes air-stable non-toxic solvent-based inks in which the commercially available precursor nanoparticles are dispersed in ethanol. Our readily achievable air-stable precursor ink, without the involvement of complex particle synthesis, high toxic solvents, or organic additives, facilitates a convenient method to fabricate a high quality CZTS absorber layer with uniform surface composition and across the film depth when annealed at $530^{\circ}C$. The conversion efficiency and fill factor for the non-toxic ink based solar cells are 5.14% and 52.8%, respectively. The other method is based on the nanocrystal dispersions that are a key ingredient in the deposition of thermally annealed absorber layers. We report a facile synthetic method to produce phase-pure CZTS nanocrystals capped with less toxic and more easily removable ligands. The resulting CZTS nanoparticle dispersion enables us to fabricate uniform, crack-free absorber layer onto Mo-coated soda-lime glass at $500^{\circ}C$, which exhibits a robust and reproducible photovoltaic response. Our simple and less-toxic approach for the fabrication of CZTS layer, reported here, will be the first step in realizing the low-cost solution-processed CZTS solar cell with high efficiency.

• Journal of the Korean Institute of Landscape Architecture
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• v.45 no.1
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• pp.35-51
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• 2017

Street gardens, a series of streetscape improvement projects led by Seoul City Government, are initiated for the purpose of providing aesthetic satisfaction and mental refreshment to pedestrians. In order to investigate whether street gardens indeed promote the psychological health of the users, questionnaire surveys were conducted on three selected street gardens - at Gangnam-daero, Digital-ro, and Teheranro - and their comparison sites located on the same streets, which have a similar physical environment but without a street garden. The survey questionnaires, based on Attention Restoration Theory, were composed of Perceived Restorativeness Scale-11 with the eleven individual questions grouped into four categories: 'Fascination', 'Being away', 'Coherence', and 'Scope'. The survey questionnaires also ask about physical components that promote psychological improvement in the aforementioned categories. The collected data was analyzed with factor analysis, reliability analysis, and independent t-test. The results suggested that street gardens had a relatively positive effect on the psychological restorativeness of the users. In particular, they gave fascination and interest to the users. However, they did not offer a feeling of being away to the users, which revealed the limitation in the psychological improvement effect of street gardens. The physical components of the street garden that have led the psychological restorativeness effect were wooden bench, tree, and flower. This result corresponds to an extant theory that natural factors have a positive effect on the psychological restorativeness within a hardscape. This research will shed light on the planning and design guidelines for the street garden project.

• Journal of Wetlands Research
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• v.16 no.2
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• pp.251-259
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• 2014

Recently, wetland and paddy wetland are being highlighted as the international environmental issues. However, research system which can assess paddy wetland is lacking. Thus, the purpose of this study is to assess the value of paddy wetland by applying RAM to paddy wetland. In addition, we would like to use this study as the data to establish assessment method for paddy wetland. 16 sites were selected as research targets based on altitude and soil. As the results of wetland assessment, 16 research target sites had total score of 212~227 and the average of 2.17~2.50. It was similar to those of Lacustrine Wetlands, Palustrine Wetland and Riverine Wetland which were sites in previous studies. The value could be recognized as the wetland. However, there was no difference in assessment results based on altitude and soil. It was found that all conservation values were the same. The factor the most closely affecting conservation value was the area. However, there was limitation to apply existing wetland assessment system to paddy wetland. In order to assess paddy wetland, factors such as rice farming methods, topography, vegetation, growth environment and biodiversity should be added. It was thought to supplement wetland assessment system through various further studies.

• Journal of the Korean Data and Information Science Society
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• v.27 no.5
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• pp.1349-1360
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• 2016

The purpose of this study was to identify the degree of quality of life (QoL) and its related factors in patients with Korean Chronic Obstructive Pulmonary Disease (COPD). With data collected by Korea National Health and Nutrition Survey in 2013, general and disease-related variables, pulmonary function test, and EuroQol-5Dimension (EQ-5D) were analyzed. The mean of EQ-5D index was 0.916 in patients with COPD and 0.941 in non-COPD. The EQ-5D index and its sub dimensions (mobility, self-care, usual activity, pain/discomfort, anxiety/depression) of COPD patients were significantly lower than that of non-COPD. However, difference in COPD patients' airway limitation was significant only for self-care of EQ-5D (${\chi}^2=9.50$, p=.013). The related factors of QoL in COPD patients were age, gender, level of education, quartile of household income, smoking status, and number of comorbid diseases. Based on the results, it is important to pay close attention to COPD patients' QoL as well as comprehensive interventions which possibly improve their QoL.

• Journal of the Korean GEO-environmental Society
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• v.17 no.6
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• pp.23-31
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• 2016

Nowadays abnormal coldness happens frequently in Korea and frost heaving causes unexpected ground deformation which results in severe problems for structures such as roadway, railroad and cutoff slope. 'Frost heave' as one of the primary phenomenon is considered to be an important factor together with 'adfreeze bond-strength' and 'creep deformation' for structural design process in permafrost area. Therefore, the fundamental study for frost heave has to be preceded for design of geo-structures in cold region. While various experimental apparatuses have been developed, there still exist a certain level of limitation to evaluate the frost-heave characteristics as design parameters. There are no standard testing method and criteria for analyzing frost heaving in Korea because temperature controlled testing apparatuses including a freezing chamber are expensive. In this paper, a new standard freezing and thawing testing apparatus is introduced, which simulates various freezing and thawing conditions in a soil specimen by using a temperature controlled triaxial cell. Frost heaving tests were performed to assess the new testing apparatus and experimental procedure to evaluate frost heaving for soils is proposed.