• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.20 no.1
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• pp.49-59
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• 1984

Optimizing investigation of characteristics of underwater welding by a gravity type arc welding process was experimentally carried out by using six types of domestic coated welding electrodes for welding of domestic marine structural steel plates (KR Grade A-1, SWS41A, SWS41B,) in order to develop the underwater welding techniques in practical use. Main results obtained are summarized as follows: 1. The absorption speed of the coating of domestic coated lime titania type welding-electrode became constant at about 60 minutes in water and it was about 0.18%/min during initial 8 minutes of absorption time. 2. Thus, the immediate welding electrode could be used in underwater welding for such a short time in comparison with the joint strength of in-atmosphere-and on-water-welding by dry-, wet-or immediate-welding-electrode. 3. By bead appearance and X-ray inspection, ilmenite, limetitania and high titanium oxide types of electrodes were found better for underwater-welding of 10 mm KR Grade A-1 steel plates, while proper welding angle, current and electrode diameter were 6$0^{\circ}C$, above 160A and 4mm respectively under 28cm/min of welding speed. 4. The weld metal tensile strength or proof stress of underwater-welded-joints has a quadratic relationship with the heat input, and the optimal heat input zone is about 13 to 15KJ/cm for 10mm SWS41A steel plates, resulting from consideration upon both joint efficiency of above-100% and recovery of impact strength and strain. Meanwhile, the optimal heat input zone resulting from tension-tension fatigue limit above the base metal's of SWS41A plates is 16 to 19KJ/cm. Reliability of all the empirical equations reveals 95% confidence level. 6. The microstructure of the underwater welds of SES41A welded in such a zone has no weld defects such as hydrogen brittleness with supreme high hardness, since the HAZ-bond boundary area adjacent to both surface and base metal has only Hv400 max with the microstructure of fine martensite, bainite, pearlite and small amount of ferrite.

• Korean Journal of Ecology and Environment
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• v.43 no.2
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• pp.190-198
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• 2010

This study was conducted to examine the effects of dams on benthic macroinvertebrate communities in Korean streams and rivers. Four low-head dams and three large dams were studied throughout South Korea. Sampling was taken at immediately upper (impoundment), lower (riffle area), and control (riffle area) sites from the dams during 2004-2007. The upper sites, of which substrate heterogeneity and velocity were relatively low, showed a lower degree of species richness, density, and diversity indices, which is very different from the lower and control sites. Heavily polluted streams showed a lesser degree of community differences between the upper and lower sites. In the large dams, the upper and lower sites showed very low values of species diversity indices and very high values of dominance indices compared to the control sites. In the low-head dams, however, the difference of degree of the values was relatively smaller. Compositions of the functional feeding groups and the habitat orientation groups were relatively simpler at the upper sites than at the lower sites and the degree of difference was greater in the large dams. Species richness and community indices of benthic macroinvertebrates were more significantly affected by habitat characteristics than water quality at the upper sites; however, those were more significantly related with water quality at the lower sites. In conclusion, large and low-head dams could simplify stream habitats particularly at the upper sites (impoundment), and they negatively affected on the benthic macroinvertebrate communities inhabited the habitats. The impact was larger in the large dams than in the low-head dams.

• Journal of dental hygiene science
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• v.13 no.3
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• pp.304-313
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• 2013

The purpose of this study was to examine the influence of the communication competence and empathy abilities of dental hygiene students on their interpersonal relationship abilities. The subjects in this study were 578 students who majored in dental hygiene at five randomly selected colleges. Out of the colleges, three were located in North Chungcheong province, and one was located in the city of Daejeon. The other one was located in South Gyeongsang province. Data were gathered using structured questionnaires from April 1 to May 7, 2013. The major findings of the study were as follows: 1. The respondents got a mean of $3.23{\pm}0.49$, $85.80{\pm}10.12$ and $83.27{\pm}8.37$ in interpersonal relationship abilities, communication competence and empathy abilities respectively. 2. As for communication competence, empathy abilities and interpersonal relationship abilities by general characteristics, there were statistically significant differences according to age, academic year, clinical practice experience and satisfaction with major. 3. The relationship of communication competence and empathy abilities to interpersonal relationship abilities was analyzed, and interpersonal relationship abilities were found to have a strong significant positive correlation to communication competence, empathy abilities and the subfactors of the two. 4. As a result of analyzing which variables affected interpersonal relationship abilities, it's found that interpersonal relationship abilities were under the influence of age, clinical practice experience, communication competence, empathy abilities. These variables made a 57.2% prediction of interpersonal relationship abilities. The above-mentioned findings suggest that communication competence and empathy abilities exerted an influence on interpersonal relationship abilities. Therefore curriculums and educational programs should be developed in consideration of these variables to ensure the stable college lives and successful relationship building of dental hygiene students who are on the way to adulthood and will serve as health care personnels in the future.

• Journal of Life Science
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• v.19 no.11
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• pp.1637-1643
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• 2009

Shikonin, a component of Lithospermum erythrorhizon Sieb. et Zucc, exerts various characteristics such as anti-inflammatory, anti-cancer and anti-obesity functions. To elucidate the molecular mechanism of shikonin-induced inhibition of adipogenesis, we analyzed the mRNA expression level of various adipogenesis-related factors including C/EBPs (CCAAT/enhancerbinding proteins) and $PPAR{\gamma}$ (peroxisome proliferator-activated receptor $\gamma$). The data showed that mRNA expressions of C/$EBP{\beta}$ and C/$EPB{\delta}$ were only slightly changed by shikonin treatment, but mRNA expressions of $PPAR{\gamma}$ and C/$EPB{\alpha}$ were significantly down-regulated. Then, we tested whether upstream regulators of C/$EBP{\beta}$ and $PPAR{\gamma}$ were involved in anti-adipogenesis of shikonin. C/$EBP{\gamma}$ and CHOP (C/EBP homologous protein), which are upstream regulators of C/$EBP{\beta}$, were not affected by shikonin treatment. On the contrary, the mRNA level of KROX20 was markedly down-regulated by shikonin treatment. These results suggest that KROX20 might regulate downstream factors of adipogenesis through C/$EBP{\beta}$-independent pathway. The expression of KLF15 (Kruppel-like factor15), which is a member of KLF family and is a upstream regulator of $PPAR{\gamma}$, was dramatically decreased by shikonin treatment, but KLF2 was not changed. Shikonin had no impact on the expression of KLF5 in the early stage of adipogenesis, but shikonin increased expression of KLF5 in the late stage of adipogenesis. Even though mRNA expression of KLF5 was moderately changed by shikonin treatment, its effect may be small compared with the effect of KLF15, which was markedly inhibited. Taken together, these results suggest that shikonin inhibits adipogenesis through the down-regulation of $PPAR{\gamma}$ and C/$EPB{\alpha}$, which is mediated by the down-regulation of two pro-adipogenic factors, KROX20 and KLF15.

• Journal of Korea Foresty Energy
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• v.21 no.1
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• pp.65-75
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• 2002

The study was carried out to determine the growth and biomass production of major deciduous trees including Betula platyphylla var. japonica, Betula schmidtii, Zelkova serrata, Acer mono, Prunes sargentii, and Ligustrum obtusifolium subjected to artificial shade treatment in nursery field. The six deciduous trees seedlings grow for 2 years under different light intensity of 100%, 38-62%, 22-28%, 7-20%, and 2-6% of the full sun light intensity. The results were as follows; In the seedling heights and root collar diameters of shade intolerant species like Betula platyphylla var. japonica and Betula schmidtii, the relative growth rates of seedlings grown in full sun showed 2 times as compared with those subjected to the shade treatment of 2-6% light intensities of full sun. In the shade tolerant species like Acer mono ant Ligustrum obtusifolium, the growth performances were better in the seedlings grown in 38-62% light intensities of full sun. Total dry mass including the dry mass of leaves, shoot and root were as a whole decreased with shade treatment. The ratio of the dry mass of leaves and stem increased the dry mass of root. T/R ratio of the seedlings increased by decreasing the relative light intensity. And the T/R ratio of 2-6% light intensities of full sun was ranged from 1.1~5.0 were greater in the full sun light was ranged from 0.6~3.2. Light intensity by artificial shade treatment decreased in deciduous trees when compared on the whole, it showed tendency that SLA increases, increased that seeing resemblant tendency in LAR and LWR and changed of light intensity is strong, it increased that showed difference as statistical. But, LWR of Betula platyphylla var. japonica increased gradually and showed tendency that decreases rapidly in the shade treatment of 2-6% light intensities of full sun. This result is thought that biomass production decreased by shading treatment influenced in physiological characteristics such as leaf area and decrease of the leaf amount.

• Korean Journal of Environment and Ecology
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• v.32 no.4
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• pp.425-439
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• 2018

W investigated the environmental factors and inhabiting biota such as macrophytes and zooplankton in 43 sites located on Jeju Island from May and June 2017 to evaluate the spread and ecosystem risk of dotted duckweed (landoltia punctata) which was recently found for the first time in Jeju Island. Dotted duckweeds were found in a total of 18 sites which tended to show low biomass of aquatic macrophyte species other than the dotted duckweed. We conducted a pattern analysis using SOM (Self-Organizing Map), which extracts information through competitive and adaptive properties, to analyze the effect of inhabiting biota on aquatic macrophytes such as the dotted duckweed and environmental factors. The SOM analysis showed that the inhabiting biota such as the zooplankton affected the biomass of aquatic macrophytes than they did the environmental factors. In particular, the biomass of dotted duckweed was positively related to plant-attached species (Alona, Chydorus, and Pleuroxus). Considering that low density of aquatic macrophytes covers the streams and wetlands on Jeju Island because of irregular water source and sharp change of water depth, the dotted duckweeds are likely to play an essential role as the vital habitat for micro-biota including zooplankton in wetlands and streams on Jeju Island. Furthermore, considering that organic matters are utilized as the primary food source in the areas occupied by dotted duckweed, dotted duckweeds have the role of being both habitat and food source. Although the dense growth of dotted duckweed adversely affects growth and development of some aquatic plants due to the shadow effect, it is due to the dominance of floating plants on the water surface should not be regarded as the risk of the dotted duckweed. In conclusion, the dotted duckweeds have spread and settled in most of the water systems on Jeju Island, their impact on inhabiting biota and the aquatic environment was minor. It is necessary to monitor the distribution and spread of dotted duckweeds in the inland areas outside of Jeju Island in the future.

• The Journal of Korean society of community based occupational therapy
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• v.3 no.1
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• pp.1-10
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• 2013

Objective : This study investigates the impact of the musculoskeletal disorder prevention exercise program designed on the basis of agricultural work posture on the balance ability, Oswestry Disability level, and Psychosocial stress of participants from one rural village in Chungnam area. Method : The exercise program was provided to 21 farmers with musculoskeletal symptoms living in one village in Chungnam area. Such program was performed once a week, 90 minutes per session, for a total of twelve weeks from July 10 to October 11, 2008, and was constructed in a way to increase flexibility and muscular strength, taking agricultural work posture into account. The balance ability, Oswestry Disability Index, and Psychosocial Well-being Index scores were analyzed based on the data of 13 of the farmers who participated in the program for more than eight times and in all of the pre- and post-assessments. Result : Thirteen participants were all women who were 70.55(${\pm}6.78$) years old on average. Most of them were engaged in general dry-filed farming. The parts where they mainly felt the pain were low back(69.2%) and knees(61.5%), and 46.2% responded 'not healthy' to the question on the overall health status. The static balance ability when standing on the right foot significantly increased from the average 9.27(${\pm}5.53$) seconds before intervention to 14.22(${\pm}5.47$) seconds after intervention(p<.05). The Oswestry Disability Index showed a significant change, decreasing from the average 19.84(${\pm}6.89$) seconds to 14.38(${\pm}7.58$) seconds(p<.05). However, there was no change in the Psychosocial Well-being Index. Conclusion : This exercise program that has been conducted for the female farmers who are mainly engaged in the dry-filed farming has contributed to the improvement of their static ability and reduction of their Oswestry Disability Index scores. It is expected that the studies on the effects of the differentiated exercise programs depending on work characteristics will make progress in the future.

• Journal of the Korean GEO-environmental Society
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• v.18 no.7
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• pp.37-47
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• 2017

In this study, a series of full-scale field tests on prebored and precast steel pipe piles and the corresponding numerical analysis have been conducted in order to study the characteristics of pile load-settlement relations and shear stress transfer at the pile-soil interface. Dynamic pile load tests (EOID and restrike) have been performed on the piles and the estimated design pile loads from EOID and restrike tests were analysed. Class-A type numerical analyses conducted prior to the pile loading tests were 56~105%, 65~121% and 38~142% respectively of those obtained from static load tests. In addition, design loads estimated from the restrike tests indicate increases of 12~60% compared to those estimated in the EOID tests. The EOID tests show large end bearing capacity while the restrike tests demonstrate increased skin friction. When impact energy is insufficient during the restrike tests, the end bearing capacity may be underestimated. It has been found that total pile capacity would be reasonably estimated if skin friction from the restrike tests and end bearing capacity from the EOID are combined. The load-settlement relation measured from the static pile load tests and estimated from the numerical modelling is in general agreement until yielding occurs, after which results from the numerical analyses substantially deviated away from those obtained from the static load tests. The measured pile behaviour from the static load tests shows somewhat similar behaviour of perfectly-elastic plastic materials after yielding with a small increase in the pile load, while the numerical analyses demonstrates a gradual increase in the pile load associated with strain hardening approaching ultimate pile load. It has been discussed that the load-settlement relation mainly depends upon the stiffness of the ground, whilst the shear transfer mechanism depends on shear strength parameters.

• Tuberculosis and Respiratory Diseases
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• v.49 no.2
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• pp.198-206
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• 2000

Background : Pulmonary complications following bonemarrow transplantation (BMT) are common and associated with a high mortality rate. We investigated the yield, safety, and impact of fiberoptic bronchoscopy (FOB) for diagnosis of postBMT pneumoniae. Methods : From May 1997 to April 2000, 56 FOBs were performed in 52 post BMT patients for clinical pneumoniae. BMT patients with respiratory symptoms and/or pulmonary infiltrates had a thoracic HRCT(high resolution computed tomography) and bronchoscopic examination including BAL (bronchoalveolar lavage), TBLB (transbronchial lung biopsy), PSB (protected specimen brush). Results : The characteristics of the subjects were as follows : 37 males, 15 females, mean age of 31.3 years(l7-45), 35 sibling donor allogenic BMTs, 15 nonrelated donor allogenic BMTs, and 2 autologous BMTs. Fiftynine percent of FOBs (33 FOBs, 31 patients) were diagnostic. Isolated pathogens included the following : 12 cytomegalovirus (CMV) (21.4 %), 7 pneumocystis carinii (PC) (12.5 %), 11 CMV with PC (19.6 %), 2 Mycobacaterium tuberculosis (3.6%), and 1 streptococcus (1.8%). Most of the radiographic findings were diffuse interstitial lesions. CMV pneumoniae had mainly diffuse interstitial nodular lesion, and PC pneumoniae had diffuse, interstitial ground glass opacity(GGO). When CMV was accompanied by PC, a combined pattern of nodular and GGO was present. Of the 56 cases (23.2%), 13 died of CMV pneumoniae (n=2), PCP (n=2),mixed infection with CMV and PC (n=3), underlying GVHD (n=1), underlying leukemia progression (n=1), or respiratory failure of unknown origin (n=4). There was no major complication by bronchoscopy. Only 3 cases developed minor bleeding and 1 episode temporary hypoxemia. Conclusion : Based on our findings, CMV and PC are the major causes of postBMT pneumoniae. In addition, BAL can be considered a safe and accurate procedure for the evaluation of pulmonary complications after BMT.

• Journal of Intelligence and Information Systems
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• v.19 no.4
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• pp.97-121
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• 2013

With the growing importance of knowledge for sustainable competitive advantages and innovation in a volatile environment, many researches on knowledge sharing have been conducted. However, previous researches have mostly relied on the questionnaire survey which has inherent perceptive errors of respondents. The current research has drawn the relationship among primary participant behaviors towards the participation level in knowledge sharing, basically from online user behaviors on Wikipedia, a representative community for online knowledge collaboration. Without users' participation in knowledge sharing, knowledge collaboration for creating knowledge cannot be successful. By the way, the editing patterns of Wikipedia users are diverse, resulting in different revisiting periods for the same number of edits, and thus varying results of shared knowledge. Therefore, we illuminated the participation level of knowledge sharing from two different angles of number of edits and revisiting period. The behavioral dimensions affecting the level of participation in knowledge sharing includes the article talk for public discussion and user talk for private messaging, and community registration, which are observable on Wiki platform. Public discussion is being progressed on article talk pages arranged for exchanging ideas about each article topic. An article talk page is often divided into several sections which mainly address specific type of issues raised during the article development procedure. From the diverse opinions about the relatively trivial things such as what text, link, or images should be added or removed and how they should be restructured to the profound professional insights are shared, negotiated, and improved over the course of discussion. Wikipedia also provides personal user talk pages as a private messaging tool. On these pages, diverse personal messages such as casual greetings, stories about activities on Wikipedia, and ordinary affairs of life are exchanged. If anyone wants to communicate with another person, he or she visits the person's user talk page and leaves a message. Wikipedia articles are assessed according to seven quality grades, of which the featured article level is the highest. The dataset includes participants' behavioral data related with 2,978 articles, which have reached the featured article level, with editing histories of articles, their article talk histories, and user talk histories extracted from user talk pages for each article. The time period for analysis is from the initiation of articles until their promotion to the featured article level. The number of edits represents the total number of participation in the editing of an article, and the revisiting period is the time difference between the first and last edits. At first, the participation levels of each user category classified according to behavioral dimensions have been analyzed and compared. And then, robust regressions have been conducted on the relationships among independent variables reflecting the degree of behavioral characteristics and the dependent variable representing the participation level. Especially, through adopting a motivational theory adequate for online environment in setting up research hypotheses, this work suggests a theoretical framework for the participation level of online knowledge sharing. Consequently, this work reached the following practical behavioral results besides some theoretical implications. First, both public discussion and private messaging positively affect the participation level in knowledge sharing. Second, public discussion exerts greater influence than private messaging on the participation level. Third, a synergy effect of public discussion and private messaging on the number of edits was found, whereas a pretty weak negative interaction effect of them on the revisiting period was observed. Fourth, community registration has a significant impact on the revisiting period, whereas being insignificant on the number of edits. Fifth, when it comes to the relation generated from private messaging, the frequency or depth of relation is shown to be more critical than the scope of relation for the participation level.