• Structural Engineering and Mechanics
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• v.27 no.4
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• pp.393-408
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• 2007

This paper presents the findings of an experimental study to evaluate retrofit methods which address particular weaknesses that are often found in reinforced concrete structures, especially older structures, namely the lack of the required flexural and shear reinforcement within the columns and the lack of the required shear reinforcement within the joints. Thus, the use of a high-strength fiber jacket for cases of post-earthquake and pre-earthquake retrofitting of columns and beam-column joints was investigated experimentally. In this paper, the effectiveness of the two jacket styles was also compared.

• Journal of Korean Society of Steel Construction
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• v.26 no.5
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• pp.463-471
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• 2014

As building height and span is getting taller and longer, the researches to increase material's strength and serviceability are continuously performed. This study evaluated mechanical and chemical properties of newly developed high-strength steel (HSS) for building structures, namely HSA800 and verified cost-effectiveness and applicability of HSS for a tall building by comparing the analysis results of normal strength steel (SM490) model. HSA800 was manufactured by TMCP to have a good weldability in spite of HSS and satisfied Korean Industrial Standards (KS). The analysis results for evaluating cost-effectiveness show that total steel quantity could be saved approximately 30% when using HSS compared to SM490. It is expected that HSA800 will contribute to enhance constructability of building.

• Journal of the Earthquake Engineering Society of Korea
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• v.9 no.4 s.44
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• pp.43-54
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• 2005

This paper presents cost-effectiveness evaluation of semi-active control system for cable-stayed bridge under earthquake excitations with various magnitudes and frequency contents. Semi-active control system, which is operated by using Bi-stale control method on the basis of linear quadratic Gaussian (LQG) optimal controller, is designed for the benchmark control problem proposed by Dyke et at. The cost-effectiveness of the proposed control system is defined by the ratio of life-cycle costs between a bridge structure with shock transmission units and a bridge structure with the semi-active control devices. The simulated results show that the damper cost has little influence on the cost-effectiveness of the semi-active control system while the cost-effectiveness is quite sensitive to the damage cost induced by the bridge failure. It is also found that the semi-active control system guarantees relatively high cost-effectiveness for the cable-stayed bridge subject to the ground motions in the regions of moderate seismicity with soft soil condition and strong seismicity with stiff soil condition.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.8
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• pp.1647-1652
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• 2011

This paper presents the shielding effectiveness for the IEC 61000-2-9 standard when HEMP source penetrates through an aperture in a planar conducting plane of infinite extent. An integral equation is derived and solved by applying Galerkin's method of moments for calculating the electric shielding effectiveness. The electric shielding effectiveness is examined based on changing the aperture length and width. It is shown that the electric shielding effectiveness is suddenly decreases as the aperture width of 0.4 ~ 0.45${\lambda}$. It is also found that the penetrated electric field for the IEC 61000-2-9 incident field is different from the Bell Laboratory incident field, but the frequency characteristic of the electric shielding effectiveness becomes the same shape.

• Journal of Korean Library and Information Science Society
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• v.49 no.2
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• pp.79-104
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• 2018

This study was to present a model of cooperative reading practice and verify reading effectiveness on youth. For this purpose, 68 reading clubs were established in 61 districts and 8 high schools. The research groups were classified as the poor reading group, the good reading group, and the mixed-skill reading group. The cooperative reading groups were carried out for four months. We developed a questionnaire on Reading effectiveness conducted it pre- and post-test, and analyzed the results through the SPSS statistical program. We found that there was a positive change in the reading effectiveness of youth and overall-the highest effectiveness was found in the poor reading group. In addition, there was a positive change in the reading behavior of youth. The change of reading effectiveness was found to affect reading behavior.

• The Journal of Society for e-Business Studies
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• v.19 no.4
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• pp.101-117
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• 2014

A purpose of this study is to learn about the impact on organizational effectiveness by analyzing the relationship between entrepreneurship and dynamic capabilities. Investigation was based on the theory of dynamic capabilities of Teece (2002), and established a research model to study the details accordingly. The research hypothesis is as follows. First, entrepreneurship will have a significant impact on dynamic capability. Second, dynamic capabilities will have a significant impact on organizational effectiveness. Survey was conducted for employees in IT ventures, which was used to analyze 412 additional. The results are as follows. Has had a significant impact on organizational effectiveness is the relationship between entrepreneurship and dynamic capabilities. In particular, this shows that a high impact on the organizational effectiveness of the organization's dynamic capabilities are assimilation exploitation capabilities, not the absorptive transformation capability of dynamic capabilities. CEO should actively consider whether the employees of the organization are developing the assimilation exploitation capabilities to make an impact on their organization's effectiveness.

• Proceedings of the KIEE Conference
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• 1989.11a
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• pp.155-158
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• 1989

This study aims to present grounding design techniques of high resistivity sites, develop a program for grounding mesh design and prove the effectiveness of the program by comparison between simulation results and field measurements.

• International Commerce and Information Review
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• v.11 no.4
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• pp.153-182
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• 2009

This paper intends to increase the performance of export support programs for small-to-medium sized firms promoted by Korea government. A research construct is suggested for effective government support program targeted on the global marketing capability. The data is collected from the firms received the support more than once by Korean governments. The results are shown as follows. First, it is found that those firms who have high propensity to be involved in export business have shown high performance. Second, the firms with high global marketing capability have shown good performance. To be more specific, organizational commitment, strategic initiative, business differentiation, and market knowledge for target markets are found to be critical factors in successful export support program. The business differentiation strategy in target market is very critical. Finally, the degree of program management effectiveness is found to be important in high performance firms. It means that for those firms, much more advanced programs need to be developed. The government should develop diversified programs by considering the degree of global marketing capability.

• The Mathematical Education
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• v.41 no.3
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• pp.341-360
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• 2002

The purpose of the study was to investigate the effectiveness of dynamic software in solving high school analytic geometry problems compared with traditional algebraic approach. Three high school students who have revealed high performance in mathematics were involved in this study. It was considered that they mastered the basic concepts of equations of plane figure and curves of secondary degree. The research questions for the study were the followings: 1) In what degree students understand relationship between geometric approach and algebraic approach in solving geometry problems? 2) What are the difficulties students encounter in the process of using the dynamic software? 3) In what degree the constructions of geometric figures help students to understand the mathematical concepts? 4) What are the effects of dynamic software in constructing analytic geometry concepts? 5) In what degree students have developed the images of algebraic concepts? According to the results of the study, it was revealed that mathematical connections between geometric approach and algebraic approach was complementary. And the students revealed more rely on the algebraic expression over geometric figures in the process of solving geometry problems. The conceptual images of algebraic expression were not developed fully, and they blamed it upon the current college entrance examination system.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.13 no.3
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• pp.194-199
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• 2001

The turbulent flow resistance of water solution with polymer is reduced as compared with that of pure water. This effects is named th drag reduction and offers the significant reduction of the pumping power and the energy consumption. But the intense shear forces and the high temperature experienced by the polymer solution when passing through the pipes cause the degradation a loss of drag reduction effectiveness. Especially, the degradation behavior is found to be strongly dependent on temperature. This mechanical and thermal degradation can be avoided by adding materials such as surfactant to the polymer solution, which enhance the bonding force between molecules. In the present study, Copolymer and SDS were utilized and they were mixed in 10 different mixture ratios, while total concentration was fixed as 100wppm. Degradation of Copolymer-SDS mixture solutions was investigated experimentally in closed loop at the temperature of $10^{\circ}C\; and\; 80^{\circ}C$ with various flow average velocities of 1.5 m/sec, 3.0m/sec, and 4.5m/sec. Degradation characteristics of polymer solution without surfactant show a radical loss of drag reduction effectiveness at high temperature. Degradation alleviation ability of surfactant is especially effective at high temperature. Consequently, this results show that the addition of surfactant to the polymer solution can control unfavorable degradation phenomena for high temperature systems.