• Korean Journal of Agricultural Science
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• v.32 no.1
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• pp.29-42
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• 2005

During a long journey of agricultural products from the production area to markets, the quality of agricultural products was always affected by some degree of vibration. The vibration input during the transportation may cause serious agricultural product injury, and this damage is particularly severe whenever the vegetable inside package is free to bounce, and is vibrated at its resonant frequency. The objectives of this study were to determine the resonant frequency of the oriental melon and to investigate the relationships between resonant frequency and physical properties of the oriental melon such as mass, volume and major and minor axes. In this study vibration testing device was constructed to determine the vibration response of the oriental melon in frequency ranges of 5 to 150 Hz. The computer program for controlling the vibration shaker and the function generator and measuring the vibration characteristics of the oriental melon was developed. The ranges of resonant frequency and peak acceleration at resonance of the oriental melon were 51 to 73 Hz and 1.24 to 1.92 G-rms, respectively. The resonant frequency and the peak acceleration decreased with the increase of the sample mass, volume, major and minor axes of the oriental melon. Multiple regression models for resonant frequency and peak acceleration of the oriental melon as a function of mass, major axis and minor axis of the sample were developed and analyzed.

• Management & Information Systems Review
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• v.35 no.1
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• pp.23-50
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• 2016

The purpose of this study is to investigate the determinants of employees' knowledge contribution to 'Easysam', the Defense Knowledge Sharing System(DKSS), and provide managers and system designers with implications for enhancing the usage of the DKSS. Although the system seems to be helpful for employees to conduct their tasks by sharing and applying knowledge from the system, use of the system is confined to restricted employees and little empirical, systematic research has been done for this area. Therefore, using the motivation opportunity ability theory of behavior, this study hypothesizes that motivation factors(enjoy helping, reward confirmation), opportunity factor(system accessibility), and ability factor(self-rated expertise, tenure in the field) increase the level of employees' knowledge contribution to the DKSS. This research also includes hypotheses which address the effect of system use voluntariness, a moderator, on the relationship between predictors described above and knowledge provision. Survey results show that the effect of enjoy helping, reward confirmation, self-rated expertise and system accessibility is significant on employees knowledge provision. However, tenure in the field has no influence on its contribution of knowledge to the system. Theoretical and practical implications are provided.

• Korean Journal of Social Welfare
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• v.59 no.1
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• pp.55-85
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• 2007

This study analyzed the effect of the inclusion program executed in a social welfare institution for handicapped children of community in order to support inclusive education of elementary school. The statistical analyses adapted in this study were the Frequency Analysis, T-test, One-Way ANOVA, Correlation Analysis, Two-Way ANOVA, and ANCOVA. As the results of the analyses, there was significant difference of the increase in the scores between pre-test attitude and attitude improvement of normal children (nonhandicapped children) by intervention of the inclusion program. Secondly three variables such as the sex, the experience of integrated class, and the school environment gave influence on attitude improvement of normal children, but two variables such as the school year and the religion didn't give influence on attitude improvement of normal children. However, as the results of the ANCOVA, it was appeared that both the school year variable and the religion variable didn't give influence on attitude improvement of normal children. Consequently, as the attitude improvement of normal children was irrelevant to the characteristic variables such as the school year and the religion, it is verified that the inclusion program gives still significant impact in the difference between pre-test attitude and attitude improvement of normal children. In conclusion, As the pure effectiveness of the inclusion program executed in social welfare institutions for handicapped children in order to support inclusive education of elementary school was confirmed, it was suggested in this study that the inclusion program in the field of social work practice based community can be an important tool of social integration through inclusive education between handicapped children and normal children.

• Journal of the Korean Society of Propulsion Engineers
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• v.4 no.3
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• pp.64-73
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• 2000

The joint parts was composed of inner AL(aluminum) ring, FRP wedge and motor case which was manufactured by filament wound method. Where the motor case consists of helical and hoop layer. The finite element analysis was performed for the design variable of joint parts to improve the performance of motor case. Where the adhesive layer was modeled to elasto-perfect plastic material and the contact condition of AL ring and wedge was modeled by using the contact surface element of ABAQUS. And the sliding distance of AL ring and the hoop strain of composite case were compared to hydro-static test results to verify the accuracy of analysis results. When wedge and AL ring was perfect bonding, though the hoop strain of joint part was reduced, the maximum shear stress was occurred at the adhesive layer. Thus the adhesive layer had failed due to the high shear stress before the failure was occurred at the case. And as another design method, when wedge and AL ring was contact condition, the shear stress on adhesive layer was decreased. But the hoop stress of joint part increased due to the sliding behavior of AL ring. Finally, the fail was occurred at the composite case of joint part. The improved joint method reinforced by hoop layer to the joint parts under contact condition for wedge and Al. ring reduced the joint part's hoop strain by constraint the sliding behavior of AL ring.

• Proceedings of the KSR Conference
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• 2006.11b
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• pp.802-810
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• 2006

For a thorough train control, the precise train position detection is necessarily required. The widely used current way for train position detection is the one of using track circuits. The track circuit has a simple structure, and has a high level of reliability. However trains can be detected only on track circuits, which have to be installed on all ground sections, and much amount of cost for its installation and maintenance is needed. In addition, for the track circuit, only discontinuous position detection is possible because of the features of the closed circuit loop configuration. As the recent advances in telecommunication technologies and high-tech vehicle-based control equipments, for the train position detection, the method to detect positions directly from on trains is being studied. Vehicle-based position detection method is to estimate train positions, speed, timing data continuously, and to use them as the control information. In this paper, the features of GPS navigation and DR navigation are analyzed, and the navigation filters are designed by constructing vehicle-based train position detection method by combining GPS navigation and DR navigation for their complementary cooperation, and by using kalman filter. The position estimation performance of the proposed method is also confirmed by simulations.

• Fire Science and Engineering
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• v.27 no.4
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• pp.27-34
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• 2013

The high prediction performance of fire detector models is essentially needed to assure the reliability of fire and evacuation modeling in the process of PBD (Performance Based fire safety Design). The main objective of the present study is to measure input information in order to predict the accurate activation time of smoke detector into a Large Eddy Simulation (LES) fire model such as FDS (Fire Dynamics Simulator). To end this, FDE (Fire Detector Evaluator) which can measure the device properties of detector was developed, and the input information of Heskestad and Cleary's models was measured for a ionization smoke detector. In addition, the activation times of smoke detectors predicted using default values into FDS and measured values in the present study were systematically compared. As a result, the device properties of smoke detector examined in the present study showed a significant difference compared to the default values used into FDS, which resulted in the considerable difference of up to 15 minutes or more in terms of the activation time of smoke detector. The database (DB) on device properties of various smoke and heat detectors will be built to improve the reliability of PBD in future studies.

• Journal of the Korean Geotechnical Society
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• v.18 no.5
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• pp.251-260
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• 2002

Geotextile tribes are made of sewn geotextile sheet and hydraulically or mechanically filled with dredged materials. They have been applied in hydraulic and coastal engineering in recent years(shore protection structure, detached breakwater, groins, and jetty). Therefore, it is composed of geotextile and confined fill material. Recently, new preliminary design criteria supported by model and prototype tests, and some stability analysis calculations have been studied. The stability analysis of geotextile tube is composed of geotechnical and hydrodynamic analysis. The stability check points are sliding failure, overturning, bearing capacity failure against the wave attack. In this paper are presented the stability analysis method by empirical equation and 2-D equilibrium analysis for geotextile tube. Also, the hydraulic model tests were performed to verify the theoretical stability analysis with geotextile tube shape, filling ratio, significant wave height, and so on. The results of this study show that the stability of geotextile tube depends on the tube shape, contact area, projection area. The theoretical analysis and hydraulic model test show almost the same results.

• Journal of the Korean Geotechnical Society
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• v.34 no.5
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• pp.19-35
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• 2018

The necessity of predicting the spatial information of the site-specific seismic response, which is essential information for the comprehensive earthquake disaster countermeasures, is increasing for the mid-west urban areas where the earthquake-induced damages can be increased due to frequent occurrence of mid-scale earthquake such as 2016 Gyeongju Earthquake and 2017 Pohang Earthquake. Especially, researches on strategic securing of site survey datasets and understanding the site-specific site response characteristics were conducted for Gyeonggi-do, South Korea. In this study, a GIS-based framework for site-specific assessment of site response and induced vulnerable area in Gyeonggi-do, South Korea was proposed. Geo-Data based on GIS platform was constructed for regional estimation of geotechnical characteristics by collecting borehole and land coverage datasets. And the geo-spatial grid information was developed for deriving spatial distribution of geotechnical layer and site response parameters based on the optimization of the geostatistical interpolation method. Accordingly, base information for Improving earthquake preparedness measures was derived as seismic zonation map with administrative sub-units considering the quantitative site effect of Gyeonggi-do.

• Journal of the Korean BIBLIA Society for library and Information Science
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• v.31 no.1
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• pp.285-310
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• 2020

A significant number of studies have been conducted on user perceptions of archive and record contents for the National Archives of Korea (NAK) and local record centers in the field of archives and records management in Korea. Yet, there has not been such a research on the use of digital archive contents designed for contents creation. Accordingly, this study investigated user perceptions of the use of the contents on the Korea Creative Content Agency (KOCCA)'s Culturing archive designed for creation purposes. A survey was conducted, examining the user's degree of interests, the expected user preference of the use and the expected extent of help by the contents of the archive. For the analyses of the survey data, this study performed one-way ANOVA for the comparative analyses of the means related to the subjects' general characteristics and the perceptions, along with cross-tabulation analyses for the association among the same items and nominal variables related to perceptions. On the basis of these analyses, this study suggests the following: ① to supplement the contents of the archive; ② to design customized interfaces and to enhance the readability; ③ to reinforce site PRs for large portal sites and creators' groups.

• Journal of the Korea Concrete Institute
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• v.13 no.2
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• pp.99-106
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• 2001

The main objective of this study is to develop a continuity of double tee slab with two modified dap-ends to solve the problems of excessive moment, slab depth, deflection, and joint cracking in the original simply supported double tee slab systems. The modified joint is produced in a combination with two slabs with modified dap and one rectangular beam. The modified joint can be justified as following different merits. The span capacity for a design load is increased, while the deflection of the slab is decreased due to the decrease of positive moment at the center span of the slab. The joint cracking between slab and beam, which occur frequently in the original slab systems of double tee will be reduced. No more additional form work is needed to cast topping concrete for continuity. Three point loading tests are performed on the specimens with a variable of an amount of main longitudinal reinforcement to evaluate flexural and shear behavior. Following conclusions are obtained from the experimental investigation. The continuity of double tee slab effectively is provided by placing longitudinal steel reinforcement in the topping concrete over the connection, and generally leads to an increase in span capacity of double tee slabs with reduced deflection. It is more effective to control the initial cracking at the connection than that of some simply supported double tee slab systems.