• Proceedings of the Korean Society For Composite Materials Conference
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• 2003.04a
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• pp.87-90
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• 2003

In this paper, the electromechanical displacements of curved actuators such as THUNDER are calculated by finite element method to design the optimal configuration of curved actuators. To predict the pre-stress in the device due to the mismatch in coefficients of thermal expansion, the adhesive as well as metal and PZT ceramic is also numerically modeled by using hexahedral solid elements. Because the modeling of these thin layers causes the numbers of degree of freedom to increase, large-scale structural analyses are performed in a cluster system in this study. The curved shape and pre-stress in the actuator are obtained by the cured curvature analysis. The displacement under the piezoelectric force by an applied voltage is also calculated to compare the performance of curved actuator. The thickness of metal and adhesive, the number of metal layer are chosen as design factors.

• Journal of Community Nutrition
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• v.8 no.4
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• pp.165-170
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• 2006

This study was conducted to develop and apply a computer-based multimedia nutrition education program for preschoolers based on the Dick and Carey model of instructional design. The Dick and Carey model included 4 phases: analysis, design, development, and evaluation. The program's instructional goals, objectives, assessment instruments, content, examples, and practice questions with feedback were written in the design phase. To be familiar with the 5 food groups, 'Nutrition exploration' were programmed using Hyperstudio. 'Nutrition exploration' was designed as a five-session, interactive multimedia game, with each session taking about 5 minutes to complete. Nineteen preschoolers, aged 6, volunteered to participate formative evaluation. The effectiveness of the program was examined using a pre-post test design. Participants were recruited by personal contact at the individual preschool education center. The application was carried out during 4 weeks. The results showed that intervention participants significantly increased knowledge between pre-test and post-test. The results support using IMM (interactive multimedia) to disseminate nutrition education to the target population. This research provides the basis for continuing development of computer-based nutrition education materials.

• Journal of the Korea Furniture Society
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• v.17 no.4
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• pp.115-129
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• 2006

This study explored the literature review for intending to make contemporary furniture expressed as postmodern aesthetics accessible to the broadest possible public, particularly through an examination and realization of art and everyday life, using qualitative analysis about the related literature as the principal methodology. The postmodern furniture aesthetics of communication expressed through double-coding, which was seen by Charles Jencks as the defining element of Post-Modernism, is characterized by the use of ideas from the traditions of craft. Hence, I dealt with pre-Modern furniture and Modern-furniture aesthetics as the background of postmodern furniture called New design furniture. As a result, contemporary furniture called New design furniture represented the use of ornament, craftsmanship, or beauty from the traditions of craft, which was a main source for communication value in postmodern furniture aesthetics.

• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.2
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• pp.205-214
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• 2004

This paper presents design concepts, specifications and performances of a newly developed Black Box, the reconstruction analysis tool with the records, and results of validation tests. The Black Box can detect crash accidents automatically, and record the vehicle's motion and driver's maneuvers during a pre-defined time period before and after the accident. The items of the Black Box included the acceleration, yaw-rate, vehicle speed, engine RPM, braking application, steering and several digital inputs for recording driver's maneuvers. To detect the accident-related-crash, it is important to understand characteristics of the crash signal, which are much different from those of normal driving. Therefore, analytical considerations should be taken in designing pre-filtering circuits and selecting appropriate parameters for identifying crash accidents. And, it is necessary to select proper combination of motion sensors and design proper pre-filtering circuits in order to describe the vehicle's motion. The analysis algorithms were developed and implemented which can perform accurate detection of crash accidents, simulating pre-crash trajectories, and calculating parameters for reconstruction analysis of crash accidents. The developed Black Box was installed on passenger cars and several types of validation tests were conducted. Through the tests, the accuracy of the recorded data and usefulness of the analysis tool for reconstruction have been validated.

• Korean Institute of Interior Design Journal
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• v.14 no.1
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• pp.142-150
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• 2005

This study is arranged the principles of the preservation and restoration in pre-modern architecture, presented guideline of the Intoner restoration in there, and attempted relative-analysis by cases of Japan in curtain of Saporo Houheikan. The method of Original- restorations and Repairs must be preserved In materials and technologies in order to hand over the future generations. The process and method of restorations are the important Cultural Properties as Architecture's itself. And Restorations of industrial manufactures hold the the important position in restoration of pre-modern Architectures. Because industrial technologies are developed and forgotten in rapid. Specially, because industrial materials as curtains were apt to recognize as consumption goods, historicity in that are contained the history of fabric, industrial technologies, and relations of traditional technologies. Conclusionaly, restorations of interior materials in our country are required of \circled1the construction of workframe in search and restoration for original preservation, \circled2the conception of refaires and establishment of investigation, \circled3the stocking of restoration-technologies of pre-modern cultural properties of architectures, \circled4the recognitions of record-preservation, \circled5the improvement of organization, upbring of technicians, establishment of theorical systems.

• Computers and Concrete
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• v.17 no.2
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• pp.201-214
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• 2016

The outer tank of a liquefied natural gas (LNG) storage tank is a longitudinally and meridianally pre-stressed concrete (PSC) wall structure. Because of the current trend of constructing larger LNG storage tanks, the pre-stressing forces required to increase wall strength must be significantly increased. Because of the increase in tank sizes and pre-stressing forces, an extreme loading scenario such as a bomb blast or an airplane crash needs to be investigated. Therefore, in this study, the blast resistance performance of LNG storage tanks was analyzed by conducting a blast simulation to investigate the safety of larger LNG storage tanks. Test data validation for a blast simulation of reinforced concrete panels was performed using a specific FEM code, LS-DYNA, prior to a full-scale blast simulation of the outer tank of a 270,000-kL LNG storage tank. Another objective of this study was to evaluate the safety and serviceability of an LNG storage tank with respect to varying amounts of explosive charge. The results of this study can be used as basic data for the design and safety evaluation of PSC LNG storage tanks.

• Journal of the Korean Society of Hazard Mitigation
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• v.10 no.1
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• pp.1-7
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• 2010

Rural facilities need to be changed to be industrialized and long span structures due to accelerating aging of the rural population. In this study, the optimized structure was developed by applying Pre-Engineered Building System using the tapered member to make that the Korea standard green house has a long span. When considering design load, reasonable values were adapted by reviewing existing design codes. As a result, applying pre-engineered building system was efficient in structural system that has span longer than 16 m. And it was concluded that the increase with the longitudinal span from 4 m to 12 m was more efficient in aspect of steel amount.

• IEIE Transactions on Smart Processing and Computing
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• v.4 no.4
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• pp.291-296
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• 2015

This paper describes the design of a high-speed comparator for high-speed automatic test equipment (ATE). The normal comparator block, which compares the detected signal from the device under test (DUT) to the reference signal from an internal digital-to-analog converter (DAC), is composed of a rail-to-rail first pre-amplifier, a hysteresis amplifier, and a third pre-amplifier and latch for high-speed operation. The proposed continuous comparator handles high-frequency signals up to 800MHz and a wide range of input signals (0~5V). Also, to compare the differences of both common signals and differential signals between two DUTs, the proposed differential mode comparator exploits one differential difference amplifier (DDA) as a pre-amplifier in the comparator, while a conventional differential comparator uses three op-amps as a pre-amplifier. The chip was implemented with $0.18{\mu}m$ Bipolar CMOS DEMOS (BCDMOS) technology, can compare signal differences of 5mV, and operates in a frequency range up to 800MHz. The chip area is $0.514mm^2$.

• Tribology and Lubricants
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• v.38 no.2
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• pp.63-69
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• 2022

In this research, the rotordynamic characteristics of the labyrinth seal with and without swirl brake were predicted using the computational fluid dynamic (CFD) model. Based on previous studies, a simple swirl brake consisting of square vanes without stagger angle is designed and placed in front of the seal inlet. The rotating frame of reference is utilized to consider the whirling motion of the rotor in the steady-state analysis since the whirling motion is transient behavior in nature. CFD analysis was performed in the range of -1 to 1 pre-swirl ratio for a given seal and swirl brake design and operating conditions. The CFD analysis result shows that the swirl brake effectively reduces the pre-swirl since the circumferential fluid velocity of labyrinth seal with swirl brake was lower than that without swirl brake. The cross-coupled stiffness coefficient, which is greatly affected by the circumferential fluid velocity, increased with an increasing pre-swirl ratio in a seal without a swirl brake but showed a low value in a seal with a swirl brake. The change in the damping coefficient was relatively small. The effective damping coefficient of the labyrinth seal with swirl brake was generally constant and showed a higher value than the labyrinth seal without swirl brake.

• Educational Technology International
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• v.24 no.2
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• pp.169-202
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• 2023

This study aims to develop instructional design strategies included in educational programs that can effectively improve the educational data literacy of pre-service teachers. We used the design and development model proposed by Richey and Klein and investigated its internal and external validity. Internal validity assessment involved the input of five experts who evaluated the initial instructional strategies. We conducted an educational data literacy education program with 29 pre-service teachers from Korean colleges and graduate schools for external validity. The effectiveness of the program was verified by the Wilcoxon Rank Sum Test, which revealed a meaningful statistical difference between Wilcoxon Rank Sum Test post-scores after the four weeks of online classes. Therefore, this study developed instructional strategies followed by the steps of data-based decision-making: the final instructional strategies encompass 21 strategies, categorized for implementation before, during, and after classes, accompanied by 38 detailed guidelines. This approach bears notable significance as it encapsulates actionable and effective instructional strategies thoughtfully tailored to the unique circumstances and educational setting of the field, as well as the specific characteristics and requirements of the learners.