• The Journal of Korean Academy of Prosthodontics
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• v.38 no.5
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• pp.583-594
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• 2000

Dislodgement of a crown or extension bridge and the loosening of a retainer of a bridge is a serious clinical problem in fixed restoration. Generally these problems are considered to be associated with deformation of the restoration. During biting, the restoration is subjected to complex forces and deforms considerably within the limit of its elasticity. Deformation of the restoration under the occlusal force induces excessive stress in the cement film, which then leads to the cement fracture. Such a fracture may eventually cause loss of the restoration. Because most of the past retention tests for full veneer crown were done without fatigue loading, they were not exactly simulating intraoral environment. And the purpose of this study was to evaluate the effect of cyclic cantilever loading on the retentive strength of full veneer crowns depending on different type of cements and taper of prepared abutment. Steel dies with $8^{\circ}\;or\;16^{\circ}$ convergence angle were fabricated through milling and crowns with the same method. These dies and crowns were divided into 8 groups. Group 1 : $16^{\circ}$ taper die, cementation with zinc phosphate cement, without loading Group 2 : $16^{\circ}$ taper die, cementation with zinc phosphate cement, with loading Group 3 : $8^{\circ}$ taper die, cementation with zinc phosphate cement, without loading Group 4 : $8^{\circ}$ taper die, cementation with zinc phosphate cement, with loading Group 5 : $16^{\circ}$ taper die, cementation with Panavia 21, without loading Group 6 : $16^{\circ}$ taper die, cementation with Panavia 21, with loading Group 7 : $8^{\circ}$ taper die, cementation with Panavia 21 without loading Group 8 : $8^{\circ}$ taper die, cementation with Panavia 21, with loading After checking the fit of die and crown, the luting surface of dies and inner surface of crowns were air-abraded for 10 seconds. The crowns were cemented to the dies, with cements mixed according to the manufacturer's recommendations. A static load of 5kg was then applied for 10 minutes with static loading device. Twenty-four hours later, group 1, 3, 5, 7 were only thermocycled, group 2, 4, 6, 8 were subjected to cyclic loading after thermocycling. Retentive tests were performed on the Instron machine. From the finding of this study, the following conclusions were obtained 1. Panavia 21 showed significantly higher retentive strength than zinc phosphate cement for all groups (p<0.05). 2. There was a significant difference in the retentive strength between $8^{\circ}\;and\;16^{\circ}$ taper for zinc phosphate cement(p<0.05), but no significant difference for Panavia 21 (p>0.05). 3. Cyclic loading significantly decreased the retentive strength for all groups(p<0.05). 4. For zinc phosphate cement, there was 35% reduction of the retentive strength after loading in the $16^{\circ}$ taper die, 25% in the $8^{\circ}$ taper die, and for Panavia 21, 21% in the $16^{\circ}$ taper die, 18% in the $8^{\circ}$ taper die.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.15 no.4
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• pp.161-173
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• 2020

As ICT convergence technology has spread and applied to various industrial fields and society in general, interest in rural entrepreneurship using smart farm as a means for solving many pending problems in agriculture is increasing. In this context, this study is to look at the influential factors in terms of perceived usefulness associated with the rural entrepreneurial intention using smart farm and suggest a proposal for spreading smart farms. The subjects were 296 general adults over 20 years old who were selected by simple random sampling method. The research method was exploratory factor analysis and multiple regression analysis using IBM SPSS 22.0. The perceived usefulness of smart farm, which are availability, reliability and economic efficiency were selected as independent variables to analyze the influential factors on rural entrepreneurial intention using smart farm and the moderating effect of personal innovation was observed. As a result, reliability and economic efficiency have a positive(+) influence on rural entrepreneurial intention using smart farm. And personal innovation moderates the relationship between the availability, reliability of smart farm and rural entrepreneurial intention using smart farm. The results of this study have significance in that we devised and empirically revealed factors affecting rural entrepreneurship intentions from the perspective of perceived usefulness of smart farms, away from studies of general entrepreneurship intention factors such as internal personal characteristics and external environmental factors. The implications of the study are expected to be utilized at the seeking direction of policy for potential entrepreneur using smart farm, the training and consulting in actual field of smart farm.

• Journal of Digital Convergence
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• v.12 no.7
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• pp.411-418
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• 2014

This study, in order to establish the effect of three exercise groups on the static and dynamic balancing abilities and the muscular activity, targeting adult males aged 20-29, assigned 15 men to each aquatic exercise group, trunk stabilization exercise group, and balance exercise group. The study was conducted from June, 2013 to August, 2013, and measured and compared the balancing ability and the muscle activity(tibialis anterior and gastrocnemius muscle) of the participants after performing intervention for 30 minutes a day, 3 days a week, for 6 weeks. As a result, on the comparison between before and after the intervention, there were significant differences in changes of the surface area and the whole path length in all the three groups(p<.05)(p<.01), and also on the dynamic balance, there was a significant difference in change of limited of stability(p<.05)(p<.01). On change of the muscle activity of tibialis anterior, both left and right sides showed statistically significant differences in all the three groups(p<.05)(p<.01), and gastrocnemius muscle showed a statistically significant difference in all the three groups except for the left side of the trunk stabilization exercise group(p<.05)(p<.01). It could be established that aquatic exercise is effective for improvement of the balancing ability and increase of the muscular activity, and we intend to propose specific aquatic exercise program development by conducting a study to determine the objective effect of aquatic exercise on the elderly or patients who have a poor balancing ability.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.22 no.1
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• pp.5-10
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• 2012

In general, the fabrications of the LEDs with mesa structure are performed grown by MOCVD method. In order to etch and separate each chips, the LEDs are passed the RIE and scribing processes. The RIE process using plasma dry etching occur some problems such as defects, dislocations and the formation of dangling bond in surface result in decline of device characteristic. The SAG method has attracted considerable interest for the growth of high quality GaN epi layer on the sapphire substrate. In this paper, the SAG method was introduced for simplification and fabrication of the high quality epi layer. And we report that the size of selective area do not affect the characteristics of original LED. The diameter of SAG circle patterns were choose as 2500, 1000, 350, and 200 ${\mu}m$. The SAG-LEDs were measured to obtain the device characteristics using by SEM, EL and I-V. The main emission peaks of 2500, 1000, 350, and 200 ${\mu}m$ were 485, 480, 450, and 445 nm respectively. The chips of 350, 200 ${\mu}m$ diameter were observed non-uniform surface and resistance was higher than original LED, however, the chips of 2500, 1000 ${\mu}m$ diameter had uniform surface and current-voltage characteristics were better than small sizes. Therefore, we suggest that the suitable diameter which do not affect the characteristic of original LED is more than 1000 ${\mu}m$.

• Journal of Environmental Science International
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• v.23 no.12
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• pp.2045-2056
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• 2014

In this study, pressure drop was measured in the pulse jet bag filter without venturi on which 16 numbers of filter bags (Ø$140{\times}850{\ell}$) are installed according to operation condition(filtration velocity, inlet dust concentration, pulse pressure, and pulse interval) using coke dust from steel mill. The obtained 180 pressure drop test data were used to predict pressure drop with multiple regression model so that pressure drop data can be used for effective operation condition and as basic data for economical design. The prediction results showed that when filtration velocity was increased by 1%, pressure drop was increased by 2.2% which indicated that filtration velocity among operation condition was attributed on the pressure drop the most. Pressure was dropped by 1.53% when pulse pressure was increased by 1% which also confirmed that pulse pressure was the major factor affecting on the pressure drop next to filtration velocity. Meanwhile, pressure drops were found increased by 0.3% and 0.37%, respectively when inlet dust concentration and pulse interval were increased by 1% implying that the effects of inlet dust concentration and pulse interval were less as compared with those changes of filtration velocity and pulse pressure. Therefore, the larger effect on the pressure drop the pulse jet bag filter was found in the order of filtration velocity($V_f$), pulse pressure($P_p$), inlet dust concentration($C_i$), pulse interval($P_i$). Also, the prediction result of filtration velocity, inlet dust concentration, pulse pressure, and pulse interval which showed the largest effect on the pressure drop indicated that stable operation can be executed with filtration velocity less than 1.5 m/min and inlet dust concentration less than $4g/m^3$. However, it was regarded that pulse pressure and pulse interval need to be adjusted when inlet dust concentration is higher than $4g/m^3$. When filtration velocity and pulse pressure were examined, operation was possible regardless of changes in pulse pressure if filtration velocity was at 1.5 m/min. If filtration velocity was increased to 2 m/min. operation would be possible only when pulse pressure was set at higher than $5.8kgf/cm^2$. Also, the prediction result of pressure drop with filtration velocity and pulse interval showed that operation with pulse interval less than 50 sec. should be carried out under filtration velocity at 1.5 m/min. While, pulse interval should be set at lower than 11 sec. if filtration velocity was set at 2 m/min. Under the conditions of filtration velocity lower than 1 m/min and high pulse pressure higher than $7kgf/cm^2$, though pressure drop would be less, in this case, economic feasibility would be low due to increased in installation and operation cost since scale of dust collection equipment becomes larger and life of filtration bag becomes shortened due to high pulse pressure.

• Journal of Veterinary Clinics
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• v.32 no.2
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• pp.141-147
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• 2015

Based on the results of previous studies, endoscopic biopsy sample's quality has a major impact on its adequacy for histopathology, and that the nature of the biopsy forceps can influence the specimen quality. The present study compared the effects of three different types of endoscopic biopsy forceps and two different operators on sample quality and adequacy for histopathology in three healthy cats. Every biopsy was performed between the major papilla and caudal duodenal flexure, and each operator performed five biopsies with each type of forceps on each cat, for a total of 90 biopsies. One pathologist evaluated the quality and adequacy of the obtained samples. Biopsies performed with large-cup forceps provided heavier and longer samples than the standard round forceps. With the same size forceps, the presence of alligator teeth had no effect on sample quality or adequacy for histopathological examination and assessment. Based on the results of the present study, although the standard round forceps could be used to obtain adequate samples for histopathology, large-cup forceps such as the standard oval and alligator jaw type have the advantage of obtaining high quality endoscopic samples.

• Food Science and Preservation
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• v.24 no.2
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• pp.289-293
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• 2017

Ethanol extract of garlic peels (GPE) was investigated for its antiproliferative effects on human cancer cell lines. Human lung cancer cell line A549 treated with $500{\mu}g/mL$ GPE resulted in the growth inhibition of A549 by 90%. In stomach cancer cell AGS proliferation inhibition activity, GPE showed 45% and 71% inhibition of AGS growth at $1,000{\mu}g/mL$ and $2,000{\mu}g/mL$, respectively. GPE inhibited the growth of the breast cancer cells MCF-7 effectively at low concentration and showed 78% and 90% inhibitions of MCF-7 growth at $200{\mu}g/mL$ and $500{\mu}g/mL$, respectively. GPE showed very significant antiproliferation effect on liver cancer cell line Hep3B and inhibited Hep3B cell growth by 57% at $100{\mu}g/mL$, and the inhibition's rate increased up to 87% at $500{\mu}g/mL$. Antiproliferation effect of GPE on colorectal cancer cell HT-29 showed 15% reduction of HT-29 cell growth at $200{\mu}g/mL$ and the growth rate was reduced in a dose dependent manner up to $1,000{\mu}g/mL$. These results indicated that GPE had high antiproliferation effects on breast and liver cancer cell lines at low concentrations ($200{\mu}g/mL$), and by higher concentrations over $500{\mu}g/mL$, GPE inhibited the growth of A549 and HT-29. The results of our study suggested the potential use of garlic peels for use as an excellent antiproliferative substance for human cancer cells.

• Journal of Digital Convergence
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• v.9 no.6
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• pp.137-151
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• 2011

This dissertation aims to empirically analyze the effect of cultivation of software industry on the local economy through Inter-regional Software Input-Output Analysis. The temporal range of analysis of effect of software industry on the local economy shall be for the year 2005 since analysis is made on the basis of the Regional Industrial Input-Output Table published by the Bank of Korea in 2005, and spatial domain shall be limited to the 16 metropolitan cities and provinces, which are the standards for each administrative zone. Results of analysis of this dissertation are as follows. Firstly, average inverse matrix coefficient of software industry for each region was computed to be 1.6248, which is lower than the average inverse matrix coefficient of 1.7979 for the entire industries. Secondly, among these, inverse matrix coefficient of software industry for each region on other industry within the same region was 0.1794, which is higher than that of entire industries at 0.1382. However, average inverse matrix coefficients of software industry for each region on self-industry within the same region and entire industries in other regions were found to be 1.0119 and 0.4335, respectively, which is lower than those of entire industries at 1.0982 and 0.5616, respectively. Thirdly, domestic produces induced by final demand items of software industry for each region was the highest for Seoul with 17.3309 trillion Korean won, accounting for 81.0% of the total, followed by Gyeonggi with 2.3370 trillion Korean won, 10.9% of the total. Fourthly, distribution ratios of domestic produces induced by final demand items of software industry for each region were found to be 19.1%, 72.1% and 8.8% with respect to the weight of consumption, investment and export, respectively, thereby illustrating very high level of distribution ratios of domestic produces being induced by investment in comparison to the distribution ratios of domestic produces being induced for the entire industries at 47.3%, 19.8% and 32.9%, respectively.

• Management & Information Systems Review
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• v.36 no.2
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• pp.157-185
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• 2017

This study was carried out with the attention that the concept of entrepreneurial orientation has been applied at various levels of CEO, employee, management, and organization as a whole. The differences between these concepts were examined by discriminant validity and convergence validity, and the causal relationship between these concepts and performance was analyzed. A total of 96 questionnaires were collected and analyzed. The results show that CEO's entrepreneurial orientation, employee's entrepreneurial orientation, manager's entrepreneurial orientation and organizational entrepreneurial orientation have convergent validity and discriminant validity, and that these variables have different effects on the firm 's innovation performance and financial performance. In the analysis of the mediating effect, when the variables of all levels were put into a single variable, the innovation performance mediates between the entrepreneurial orientation and the financial performance in all variables. However, when all variables are applied simultaneously, innovation performance has mediating effect only on the relationship between organizational entrepreneurship orientation and financial performance. This shows that there is a conceptual difference according to applied level. As a result of the analysis of the causal relationship by the application level of entrepreneurial orientation, it is found that causality is formed among the entrepreneurial orientation variables. In particular, CEO's entrepreneurial orientation influences employee's entrepreneurial orientation, manager's entrepreneurial orientation, and organization's entrepreneurial orientation, and again, employee's entrepreneurial orientation and managerial entrepreneurial orientation form a causal relationship that influences organization's entrepreneurial orientation. In the relationship between innovation performance and financial performance, CEO's entrepreneurial orientation, organization's entrepreneurial orientation, and manager's entrepreneurial orientation are influencing innovation performance, and the only variables influencing financial performance are organization's entrepreneurial orientation. In conclusion, the limitations of the study and its future direction are presented.

• Cartoon and Animation Studies
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• s.36
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• pp.469-491
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• 2014

Webtoon has developed the method that makes it possible to express sound visually. Also we can also hear sound in webtoon through the development of web technology. It is natural that we analyze the sound that we can hear, but we can also analyze the sound that we can not hear. This study is based on 'dual code' in cognitive psychology. Cartoonists can make visual expression on the basis of auditive impression and memory, and readers can recall the sound through the process of memory and memory-retrieval. This study analyzes both audible sound and inaudable sound. Concise analysis owes the method to film sound theory. Three main factor, Volume, pitch, and tone are recognized by frequency in acoustics. On the other hand they are expressed by the thickness and site of line and image of sound source. The visual expression of in screen sound and off screen sound is related to the frame of comics. Generally the outside of frame means off sound, but some off sound is in the frame. In addition, horror comics use much sound for the effect of genre like horror film. When analyzing comics sound using this kinds of the method film sound analysis, we can find that webtoon has developed creative expression method comparing with simple ones of early comics. Especially arranging frames and expressing sound following and vertical moving are new ones in webtoon. Also types and arrangement of frame has been varied. BGM is the first in using audible sound and recently BGM composed mixing sound effect is being used. In addition, the program which makes it possible for readers to hear sound according to scroll moving. Especially horror genre raise the genre effects using this technology. Various methods of visualizing sound are being created, and the change shows that webtoon could be the model of convergence in contents.