• The Journal of Korean Academy of Prosthodontics
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• v.46 no.5
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• pp.535-543
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• 2008

Purpose: The objective of this study was to compare the bonding characteristics of a new self-adhesive resin cement to dentin, which does not require bonding and conditioning procedure of the tooth surface, and conventional resin cement. The effect of phosphoric acid etching prior to application of self-adhesive resin cement on the shear bond strength was also evaluated. Material and methods: Fortyfive non-carious human adult molars extracted within 6 months were embedded in chemically cured acrylic resin. The teeth were ground with a series of SiC-papers ending with 800 grit until the flat dentin surfaces of the teeth were exposed. The teeth were randomly divided into 3 experimental groups. In group 1, self-adhesive resin cement, RelyX Unicem (3M ESPE, Seefeld, Germany) was bonded without any conditioning of teeth. In group 2, RelyX Unicem was bonded to teeth after phosphoric acid etching. For group 3, Syntac Primer (Ivoclar Vivadent AG, Schaan, Liechtenstein) was applied to the teeth before Syntac adhesive (Ivoclar Vivadent AG, Schaan, Liechtenstein) and Helibond (Ivoclar Vivadent AG, Schaan, Liechtenstein) followed by conventional resin cement, Variolink II (Ivoclar Vivadent AG, Schaan, Liechtenstein). To make a shear bond strength test model, a plastic tuble (3 mm diameter, 3 mm height) was applied to the dentin surfaces at a right angle and filled it with respective resin cement, and light-polymerized for 40 seconds. All the specimens were stored in distilled water at $37^{\circ}C$ for 24 hours before test. Universal Testing Machine (Z020, Zwick, Ulm, Germany) at a cross head speed of 1 mm/min was used to evaluate the shear bond strength. The failure sites were inspected under a magnifier and Scanning Electron Microscope. The data was analyzed with One way ANOVA and Scheffe test at ${\alpha}$= 0.05. Results: (1) The shear bond strengths to dentin of RelyX Unicem was not significantly different from those of Variolink II/Syntac. (2) Phosphoric acid etching lowered the shear bond strength of RelyX Unicem significantly. (3) Most of RelyX Unicem and Variolink II showed mixed fractures, while all the specimens of RelyX Unicem with phosphoric acid etching demonstrated adhesive failure between dentin and resin cement. Conclusion: Shear bond strength to dentin of self-adhesive resin cement is not significantly different from conventional resin cement, and phosphoric acid etching decrease the shear bond strength to dentin of self-adhesive resin cement.

• Journal of Aquaculture
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• v.10 no.3
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• pp.261-271
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• 1997

Ammonia removal capacities of five submerged filter media, 2~3mm sand, 30~50mm gravel, 20~40mm coral sand, polythylene net, and corrugated plastic plate in a seawater recirculating system were tested. A rotating biological contactor (RBC) was also tested for comparison. Oxygen consumption rates were measured along with the ammonia removal efficiencies. The ammonia concentrations in the system were maintained from 0.052 to 0.904 mg/l (mean 0.338$\pm$0.219 mg/l) and the water temperature was ranged from 19.2 to $21.4^{\circ}C\;(mean 20.2^{\circ}C\pm0.58^{\circ}C$). The 1/2-order kinetic model (Y:g/$m^3$/day) and the mean ammonia removal rates (g/$m^3$/day) of the filter media were : Sand : Y=135.5X0.5-25.1(r2=0.8110), 45.1 Coral sand : Y=125.1X0.5-33.0 (r2=0.7307), 31.8 Polyethylene net : Y=87.4X0.5-20.1 (r2=0.6780), 25.2 Corrugated plastic plate : Y=87.4X0.5-20.1(r2=0.5206), 19.2 Gravel : Y=4307X0.5-5.5 (r2=0.2596), 17.1 RBC : Y=127.6X0.5-33.4 (r2=0.7146), 32.8 where X is the concentration of ammonia. Oxygen consumption rates well corresponded to the ammonia removal capacities of each filter medium, thus the sands showing the highest value (442g/$m^3$/day) followed by coral sands (291.1g/$m^3$/day), polyethylene nets (236.9g/$m^3$/day), gravels (135.6g/$m^3$/day) and corrugated plastic plates (134.2g/$m^3$/day). Oxygen consumption rate of the RBC was unable to measure because of the characteristics of the structure.

• Journal of Bio-Environment Control
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• v.18 no.1
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• pp.15-22
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• 2009

Adequate environment conditions with growth stage of potato were decided in a photoautotrophic micropropagation system using models. Total 20 day-period of growth were divided into three growth periods such as 6 (stage 1), 7(stage 2), and 7(stage 3) days. At the 1st stage, no significant differences were observed in the growth of potato plantlets at various photosynthetic photon flux density (PPFD) and $CO_2$ conditions. Considering damaged leaves, $80\;mmol{\cdot}m^{-2}{\cdot}s^{-1}$ PPFD and ambient $CO_2$ level were adequate in this stage. At the 2nd stage, significant differences were partly observed in several growth characteristics including dry weight. Based on the dry matter model, over $240\;mol{\cdot}m^{-2}{\cdot}s^{-1}$ PPFD was too high to cultivate potato plantlets at this stage due to the occurrence of damaged leaves. Considering both plant growth and energy efficiency, $160\;mol{\cdot}m^{-2}{\cdot}s^{-1}$ PPFD and $700\;mol{\cdot}mol^{-1}\;CO_2$ were selected for the adequate combination. At the 3rd stage, the biomass accumulation was significantly induced in potato plantlets under higher levels of PPFD and $CO_2$ concentration as suggested by increased fresh and dry weights. However, we could not find the saturated point with regard to dry matter due to continuous increase of dry mater even under maximum PPFD ($320\;mmol{\cdot}m^{-2}{\cdot}s^{-1})$. Thus, $320\;mol{\cdot}m^{-2}{\cdot}s^{-1}$ PPFD and $1800\;mol{\cdot}mol^{-1}\;CO_2$ were considered as the best choice at final stage in this study. In conclusion, even though the growth period of micropropagated potato plantlets was quite a short, favorable environmental conditions required at each growth stage were different. This technique could improve the growth of micropropagated plantlets compared to the conventional micropropagation and apply to other agriculturally important crops as well as potato in the future.

• Journal of Bio-Environment Control
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• v.26 no.3
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• pp.151-157
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• 2017

The objectives of this study were to determine the impact of soil water content on the growth, stomatal conductance, and photosynthesis of Kimchi cabbage and to evaluate proper parameters for development of growth models. There were five levels of irrigation amount treatments (0, 200, 300, 400, and 500 mL/d/plant) and those were commenced at one day after transplanting (DAT). We measured soil water content, stomatal conductance, photosynthesis characteristics, and the A-Ci curve. The growth of Kimchi cabbage as affected by irrigation amount was evaluated at 38 days after transplanting, however, the growth with 0 and 200 mL/d/plant irrigation amount treatments measured at 29 DAT. The relationship between soil water content and stomatal conductance was highly correlated ($r^2=0.999$) and the function represented by y = 6097.4x - 4.2984. The stomatal conductance of Kimchi cabbage leaves showed $300mmol{\cdot}m^{-2}{\cdot}s^{-1}$ when the soil water content was below $0.05m^3/m^3$. The stomatal conductance was rapidly decreased by scarcity of soil moisture. A-Ci curve indicated normal curve in fully irrigation treatment (500 mL/d/plant), however, $CO_2$ couldn't diffuse through the intercellular Kimchi cabbage leaves treated with 0 mL/d/plant. The dry weight of full irrigation treatment was greater approximately 6.8 times than that of deficit irrigation (0 mL/d/plant). In addition, leaf area index showed a logarithmic function (y = 16.573 + 3.398 ln x) with soil water content and that of R-squared represents 0.913. Results indicated that the soil water content was highly correlated with stomatal conductance and leaf area index. Indeed, the scarcity soil moisture reduced photosynthesis and retarded growth.

• Asia pacific journal of information systems
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• v.21 no.1
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• pp.1-27
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• 2011

In an attempt to cope with widespread, dynamic, and accelerating changes in both internal and external business environments, companies often utilize information technologies such as SCM(Supply Chain Management). To date, SCM research has mainly focused on the effects of dynamic factors on SCM success and emphasized adoption strategies and critical success factors. Consequently, the effects of more static factors such as interdependency between SCM partners have been largely ignored. The purpose of this study, therefore, is to examine the effects of both dynamic and static factors on SCM performance by controlling for information quality and partnership quality. The five factors examined in this study include innovative ness, mutual dependency, quality of information, partnership quality, and SCM performance. All factors were examined from the perspective of part suppliers, except the mutual dependency which was examined from two aspects: supplier's dependency on customer and customer's dependency on supplier. Data was collected through five hundred survey questionnaires distributed to the part supplier companies that have implemented SCM systems for at least one year. As a result, a total of 170 valid responses were obtained. A structural equation research model was fitted using SAS 9.1.3 and SMART-PLS 2.0. The results of this study can be summarized as follows. First, innovativeness positively affected SCM information quality. SCM partnership quality, and ultimately SCM performance. The path coefficient between innovativeness and information quality was 0.387, with a t-value of 3.528. Innovativeness also had a positively direct effect on partnership quality. The path coefficient was 0.351 with a t-value of 3.366. The total effect of innovativeness on partnership quality was significant, although its indirect effect on partnership quality by altering information quality was negligible. The total indirect effect of innovativeness on SCM performance by affecting information quality and partnership quality was significant with a p-value of 0.014. Innovativeness played an important role in determining SCM performance. Second, mutual dependency showed no significant effect on SCM information quality. This result contradicts the earlier assertion that the more dependent two companies are, the more accurate and timely the information they exchange ought to be. This study showed that this may not be the case; a partner may provide information of poor quality even when it is strongly dependent on the other. Mutual dependency showed significant effect on partnership quality. However, when the mutual dependency perceived by suppliers was divided into two parts, one being a supplier's dependency on its customer company and the other being a customer's dependency on the supplier, the latter showed a significant impact on the perceived SCM partnership quality. This result indicates that a customer company can hardly improve the partnership quality perceived by suppliers by making them more dependent. It improves only when the suppliers perceive that their partners, typically having more bargaining power, are more dependent on them. The overall effect of mutual dependency of any kind on SCM performance, however, was not significant. Although mutual dependency has been mentioned as an important static factor influencing almost every aspect of cooperation on a supply chain, its influences may not be as significant as it was initially perceived to be. Third, the correlation between information quality and partnership quality was 0.448 with a p-value of less than 0.001. Information quality had a path coefficient of 0.256 to partnership quality with a t-value of 2.940. The quality of information exchanged between partners may have an impact on their partnership quality. Fourth, information quality also had a significant impact on SCM performance with a path coefficient of 0.325 with a t-value of 3.611. In this study, SCM performance was divided into four categories: product quality, cost saving, service quality, and order fulfillment. Information quality has Significant impacts on product quality, cost saving and service quality, but not on order fulfillment. Fifth, partnership quality, as expected, had a significant impact on SCM performance. The path coefficient was 0.403 with a t-value of 3.539. Partnership quality, like information quality, had positive impacts on product quality, cost saving and service quality, but showed no impact on order fulfillment. It seemed that order fulfillment is the hardest category of performance that SCM can satisfy. One major limitation of this study is that it surveyed only the suppliers. To better understand the dual aspects of SCM, it is important to survey both suppliers and the assemblers, especially in pairs. This research, to our best knowledge, was the first attempt to study the level of dependency between the two groups by measuring the dual aspects of SCM and studying mutual dependency from the categories of suppliers and assemblers each.. In the future, a more comprehensive and precise measurement of SCM characteristics needs to be achieved by examining from both the supplier's and assembler's perspectives.

• Journal of Mushroom
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• v.16 no.3
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• pp.155-161
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• 2018

In this study, we analyze the growth environment using smart farm technology in order to develop the optimal growth model for the precision cultivation of the bottle-grown oyster mushroom 'Suhan'. Experimental farmers used $88m^2$ of bed area, 2 rows and 5 columns of shelf shape, 5 hp refrigerator, 100T of sandwich panel for insulation, 2 ultrasonic humidifiers, 12 kW of heating, and 5,000 bottles for cultivation. Data on parameters such as temperature, humidity, carbon dioxide concentration, and illumination, which directly affect mushroom growth, were collected from the environmental sensor part installed at the oyster mushroom cultivator and analyzed. It was found that the initial temperature at the time of granulation was $22^{\circ}C$ after the scraping, and the mushroom was produced and maintained at about $25^{\circ}C$ until the bottle was flipped. On fruiting body formation, mushrooms were harvested while maintaining the temperature between $13^{\circ}C$ and $15^{\circ}C$. Humidity was approximately 100% throughout the growth stage. Carbon dioxide concentration gradually increased until 3 days after the beginning of cultivation, and then increased rapidly to approximately 2,600 ppm. From the 6th day, $CO_2$ concentration was gradually decreased through ventilation and maintained at 1,000 ppm during the harvest. Light was not provided at the initial stage of oyster mushroom cultivation. On the $3^{rd}$ and $4^{th}$ day, mushrooms were irradiated by 17 lux light. Subsequently, the light intensity was increased to 115-120 lux as the growth progressed. Fruiting body characteristics of 'Suhan' cultivated in a farmhouse were as follows: Pileus diameter was 30.9 mm and thickness was 4.5 mm; stipe thickness was 11.0 mm and length was 76.0 mm; stipe and pileus hardness was 0.8 g/mm and 2.8 g/mm, respectively; L values of the stipe and pileus were 79.9 and 52.3, respectively. The fruiting body yield was 160.2 g/850 ml, and the individual weight was 12.8 g/10 unit.

• Journal of Nutrition and Health
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• v.42 no.2
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• pp.119-127
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• 2009

Malnutrition of hospitalized patients can adversely affect clinical outcomes and cost. Several nutritional screening tools have been developed to identify patients with malnutrition risk. However, many of those possess practical pitfalls of requiring much time and labor to administer and may not be highly applicable to a Korean population. This study sought to develop and evaluate a Nutrition Risk Screening Tool (NRST) which is simple and quick to administer and widely applicable to Korean hospitalized patients with various diseases. The study was also designed to generate a screening tool predictable of various clinical outcomes and to validate it against the Nutritional Risk Screening 2002 (NRS 2002). Electronic medical records of 424 patients hospitalized at a general hospital in Seoul during a 14-month period were abstracted for anthropometric, medical, biochemical, and clinical outcome variables. The study employed a 4-step process consisting of selecting NRST components, searching a scoring scheme, validating against a reference tool, and confirming clinical outcome predictability. NRST components were selected by stepwise multiple regression analysis of each clinical outcome (i.e., hospitalization period, complication, disease progress, and death) on several readily available patient characteristics. Age and serum levels of albumin, hematocrit (Hct), and total lymphocyte count (TLC) remained in the last model for any of 4 dependent variables were decided as NRST components. Odds ratios of malnutrition risk based on NRS 2002 according to levels of the selected components were utilized to frame a scoring scheme of NRST. A NRST score higher than 3.5 was set as a cut-off score for malnutrition risk based on sensitivity and specificity levels against NRS 2002. Lastly differences in clinical outcomes by patients' NRST results were examined. The results showed that the NRST can significantly predict the in-hospital clinical outcomes. It is concluded that the NRST can be useful to simply and quickly screen patients at high-nutritional risk in relation to prospective clinical outcomes.

• Journal of The Korean Association of Information Education
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• v.12 no.1
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• pp.9-22
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• 2008

The purpose of this research is to develop a prototype of the support system in order for team building associated with web-based project learning having applied Kolb's learning style. To accomplish this purpose, the following research tasks were performed. First, core idea in order to embody the system's value, key activities, tools that will support pertinent activities and the strategy so as to develop guidelines, etc. were devised and prepared. Second, a system was designed on the basis of structural model of teaching design, then after, interface was developed. The core factors in this system are inspection of learning style, organizing a team and team building. Above all, it is required to make learners know about learning environments, of which they are in favor, and also its distinctive features through inspection of learning style, and then focusing on learning style, a team should be organized insomuch as to accommodate a variety of learning styles as much as possible. For the purpose of team building, after learning style of each constituent member of the team has been made known, then the roles will be divided among the constituent members of the team so as to suit their individual characteristics referring to each of their learning styles that have been exposed. To verify the value of this system developed and efficiency thereof, a focus group interview was conducted. The focus group consisted of professionals, all from related fields. After the interview, the points required to make further improvements were elicited and taken care of by follow-up actions as needed. And having reflected such improvements made, the final system was developed. With this newly developed system, learners can get the results of inspection of learning style so quickly by performing inspection any time any where, and based on the results from such inspection, a team comprising dissimilar constituents who exhibit a variety of different propensities will be automatically organized. Thus, this system may be used not only for web-based project learning having unspecified persons elected as constituents, but in the offline space also.

• Journal of the Korean Institute of Landscape Architecture
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• v.42 no.5
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• pp.1-12
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• 2014

Recently, the reenaction of place's memories that were considered sense of place based on its historical and structural characteristic were assumed important topics for recovering and making the park from industrial sites, such as factory, industrial complex, industrial city, labor residential development, landfill, etc., to the public all over the world. This research aimed to conduct some preliminary data for making the park's sense of place highly. So, after conducting the structural forms of sense of place for Seoul Forest and Seonyudo Park that were designed and built by considering its place memories actively, park planning and design implications that were considered its sense of place were suggested. The research results those were derived from the structural forms of sense of place for Seoul Forest and Seonyudo Park's are the following. First, the Structural Equation Modeling(SEM) on Seoul Forest and Seonyudo Park were determined that the natural-physical, artificial-physical, and experiential environmental factors' satisfaction of Seoul Forest and Seonyudo Park have an effect on forming the Sense of Place. In addition, the sense of place was affected by the willingness to visit. Second, according to its physical environment, the experiential factors, such as plays, exercises and etc., were more important relatively. Therefore, experiential factors should be considered significantly with physical factors to make the sense of place highly. Third, even the places were under similar category, the factors' and valuables' relative importance were changed. As the results of structural equation modeling said, specific valuables' related with each factors would be differentiated due to the places' characteristics. For example, the results were showed that natural-physical factor was more important than artificial-physical factor in Seoul Forest. On the other hand, artificial-physical factor was more important than the natural- physical factor. This research carries some significance for applying a quantitative research method(structural equation modeling) to various place to conduct the sense of place's structural model, for suggesting relative specific methods to make the sense of place, and for being a step forward to substance of sense of place. If further studies conduct focusing on various places to draw the forming models of sense of place that were based this research's analysis methods and results, those researches would contribute to make the urban place meaningful, characteristically and affectionately. Furthermore, those researches would contribute in making a humane and competitiveness city.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.15 no.3
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• pp.191-206
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• 2020

Although several studies have been conducted on unification and the life of North Korean refugees, there have been few studies comparing the characteristics of North Korean refugees with South Korean workers, in terms of human resources in business administration. By considering the limitations of these prior studies, this study analyzed whether there are differences in factors affecting organizational commitment and turnover intention through a group comparative analysis between North Korean refugees and South Korean workers. For a comparative analysis between the two groups, we recruited 145 workers from North Korea and 213 South Korea-born workers. We found the following results with a multi-group structural equation model. We confirmed the measurement homogeneity by ensuring that both groups were equally aware of the measurement tools affecting organizational commitment and turnover intentions. As a result of testing the homogeneity of measurement, we also confirmed that there was a significant difference in optimism between the two groups; optimism affects organizational commitment and among social supports, affectionate support and interaction support affect organizational commitment. Analyzing the path between the two groups, we first were able to find that optimism influenced organizational commitment for both groups, in relation to positive psychological capital. However, in terms of degree, South Korean workers were found to be strongly affected. Second, with regard to social support, we were not able to find that affectionate support and interaction support have a significant impact on organizational commitment for South Korean workers, while for North Korean refugees, we confirmed that both supports have a significant impact. Third, we were unable to find any differences between the two group, in terms of other sub-components of positive psychological capital (self-efficacy, hope, and resiliency) or the sub-components of social support (informational support, tangible support). These results suggest that companies or managers employing North Korean refugee workers need to create an organizational environment that allows them to perceive social support, especially affectionate support and interaction support.