• Transactions of the Korean Society of Mechanical Engineers
• /
• v.16 no.10
• /
• pp.1900-1907
• /
• 1992

This paper presents the vibration mode, natural frequencies and amplitudes of the circular plate due to the changes of the boundary conditions by varying free arc angles. The vibration mode, amplitudes and natural frequencies of the circular plate are obtained by time-average holographic interferometry and laser doppler vibrometer. The vibration modes of the circular plate with the mixed boundary conditions are found from the 1st mode to the 4th mode. The curve shapes of the natural frequency ratios obtained from this study are in a good agreement with other results obtained by numerical analysis. The displacement curves obtained from time average holographic interferometry and laser doppler vibrometer agree well in case of large amplitude, but show a little difference in case of small amplitude.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.15 no.8
• /
• pp.1720-1726
• /
• 2011

The DDoS attacks which are increasing recently must have many zombie PCs before attacking targeted systems by attacker. A zombie PC is infected by attacker's malignant code and may be operated by the his/her special malicious purposes. But most users generally don't know that their PCs are infected and used as zombies by illegal activities covertly. In this paper, we propose a new scheme that decreases vulnerable PCs and isolates them from Internet before being zombie PCs. The proposed scheme point the reputations of connected PCs and decide whether their Internet connections are keeping continuously or not. Also We show the figures how to infect susceptable PCs to zombie PCs, and analyze the decrease effects of DDoS attacks adapted by the proposed scheme with various experiments.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.34 no.3
• /
• pp.14-21
• /
• 2006

The unsteady vortex lattice method is used to model twisting and flapping motions of a rectangular flat plate wing. The results for plunging and pitching motions were compared with the limited experimental results available and other numerical methods. They show that the method is capable of simulating many of the features of complex flapping flight. The lift, thrust and propulsive efficiency of a rectangular flat plate wing have been calculated for various twisting angles and reduced frequency with an amplitude of flapping angle($20^{\circ}$). And the effects of the twisting on the aerodynamic characteristics of the flapping wing are discussed by examination of their trends.

• Journal of the Korean Society for Railway
• /
• v.11 no.5
• /
• pp.465-470
• /
• 2008

Sound transmission characteristics are investigated on the honeycomb panels used for railway vehicles. Equivalent orthotropic plate model and equivalent mass law are applied to predict the sound transmission loss (STL) of the honeycomb panels. The predicted values of the STL are compared with the measured values. The reliability and the limitation of the prediction models are investigated. Coincidence effect and local resonance effect on STL are considered. The result of the study shows that the equivalent orthotropic plate model can be used as a good prediction model, if the local resonance frequency is properly applied. finally, ways to improve the severe STL drop by local resonance are proposed and the effect on the sound insulation performance is analysed.

• Management & Information Systems Review
• /
• v.37 no.2
• /
• pp.63-85
• /
• 2018

Electronic displays have developed as instruments that function as windows of information to satisfy the bidirectional needs of electronic device manufacturers and users. The cathode-ray tube (CRT) display once dominated the display industry. Now, the liquid crystal display (LCD) is dominant, and promising displays are competing to become the next-generation display. Displays reflect the characteristics of the information and communication technology (ICT) industries, such as technological changes, innovative features, and competitive dynamics, and have technologically evolved to dominate the industry and market through various ICT devices. This research utilizes a dominant design concept and examines the case of the flat-panel display industry to propose a comprehensive framework, which considers technological, organizational, and environmental characteristics, of the determinants influencing dominance in the technology-intensive ICT industry. The results show that a dominant design in the flat-panel display industry emerges from technological competition among several designs, based on technological characteristics and market acceptance, and dominates the industry and market by various environmental factors. Our results emphasize the difference between generic technologies and the speed of technological innovation and expand the understanding of the emergence of a dominant design. Furthermore, this paper suggests practical implications for establishing a competition strategy and strategic guidance for other ICT industries as well as the display industry.

• The Journal of the Convergence on Culture Technology
• /
• v.9 no.6
• /
• pp.715-720
• /
• 2023

This study aims to select ESG items from a consumer perspective and examine the influence of these factors on corporate image and corporate reputation. ESG-related research tends to be conducted from a corporate or investment perspective. However, based on their evaluation of ESG activities, consumers form corporate image and corporate reputation. Accordingly, the E, S, and G evaluation items were applied from the consumer's perspective to analyze the impact of each item. As a result of the study, the impact on corporate image was found to be in the order of transparent management, support for small and medium-sized businesses, and response to climate change. The results of corporate reputation analysis showed transparent management, response to climate change, and support for small businesses. From the consumer's perspective, activities related to a company's response to climate change are considered a corporate obligation, and demands for coexistence and transparent corporate management of small and medium-sized businesses are growing. The significance of this study is that ESG requires environmental management, symbiotic management, and transparent management from a consumer point of view, suggesting that transparent corporate management is the most important factor. In addition, it suggests that communication with consumers of companies requires communication not only in the environmental area, but also in the social and governance areas.

• Journal of Energy Engineering
• /
• v.14 no.4 s.44
• /
• pp.213-218
• /
• 2005

In order to understand the heat and mass transfer characteristics of humid airflow in frosting conditions, a flat plate of aluminum with cooling modules located in the central part of the plate was used. A microscope system (resolution of 0.05 mm) was used for the measurement of local thickness of frost at seven points along the plate in the flow direction. For the total mass of frost at each test operation, an electronic balance (resolution of 1 mg) was used. The local frost thickness distributions far various test conditions were presented along with the frost mass data measured at the given operating times. The effect of humidity and velocity of humid air on frosting were analyzed.

• Geotechnical Engineering
• /
• v.13 no.3
• /
• pp.87-100
• /
• 1997

This paper presents the results of plate loading test and discontinuum analysis, carried out to study the deformation behaviour and determine the deformation modulus of !rletamorphic andesitic tuff found at the site of a underground oil storage facility in Korea. In the plate loading test, the maximum pressure of 14MPa was applied to the bedrock by using a flat jack(1m in diameter) and the rock anchor system for the reaction against the applied pressure. The values of deformation modulus obtained from this test were compared with those of laboratory test, biaxial test and pressuremeter test. The deformation modulus from plate loading test was generally about half of the intact rock modulus, and the mass modulus of the bedrock at the test site may be affected by discontinuities and ranges between 25 and 350pa. Discontinuum analysis was also performed to simulate plate loading test and study the influence of discontinuities on the deformability of rock mass by simulating the presence of joints at the test area.

• Journal of Navigation and Port Research
• /
• v.26 no.1
• /
• pp.43-49
• /
• 2002

In this Paper, the mechanical behavior of two reかangular plates spot-welded under free vibration is investigated in detail. The focus of the analysis is to evaluate the effect of thickness of reinforced plates with equivalent thickness. The results of this the investigation are compared with detailed finite element analysis end experiments of the plates spot-welded for various parameters, such as aspect ratio, arm ratio, and distance ratio of spot-welding Points. The conclusion obtained are as followed. 1. The effect thickness due to spot-weld is very large, such as 55% in comparison with area ratio of spot-welding joint is just 4.52%. 2 The effect of thickness with respect to the distance ratio is maximized when the distance ratio is 0.4.

• Journal of the Korean GEO-environmental Society
• /
• v.13 no.6
• /
• pp.5-17
• /
• 2012

The study of surface ground reinforcing method is supposed to be considered preferentially is not satisfied and also doesn't contemplate plastic flow because of repetitive drive of construction equipment. Also, Terzaghi's bearing-capacity equation and Yamanouchi's suggestion have been used to design the surface reinforcement, but most engineers depend on their experience and cases constructed before because of dispersed variables and inappropriate bearing-capacity factors. Hence, plate load test and repetitive plate load test were performed in the field which is reinforced with geotextile, Geogrid whose tensile strength are 200kN/m, 100kN/m and bamboo($0.4m{\times}0.4m$). The object of this study is to evaluate bearing capacity and behaviour of surface ground and to compare each reinforcement form test results. From the results bearing capacity ratio increased by a maximum of 1.5 times with bamboo reinforcement method comparing to others.