• Structural Engineering and Mechanics
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• v.88 no.4
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• pp.389-403
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• 2023

In order to explore the influence of tooth root cracks on the dynamic characteristics of multi-stage planetary gear transmission systems, a concentrated parameter method was used to construct a nonlinear dynamic model of the system with 30-DOF in bending and torsion, taking into account factors such as crack depth, length, angle, error, time-varying meshing stiffness (TVMS), and damping. In the model, the energy method was used to establish a TVMS model with cracks, and the influence of cracks on the TVMS of the system was studied. By using the Runge- Kutta method to calculate the differential equations of system dynamics, a series of system vibration diagrams containing cracks were obtained, and the influence of different crack parameters on the vibration of the system was analyzed. And vibration testing experiments were conducted on the system with planetary gear cracks. The results show that when the gear contains cracks, the TVMS of the system will decrease, and as the cracks intensify, the TVMS will decrease. When cracks appear on the II-stage planetary gear, the system will experience impact effects with intervals of rotation cycles of the II-stage planetary gear. There will be obvious sidebands near the meshing frequency doubling, and the vibration trajectory of the gear will also become disordered. These situations will become more and more obvious as the degree of cracks intensifies. Through experiments, the theoretical results are in good agreement with experimental results, verifying the correctness of the theoretical model. This provides a theoretical basis for fault diagnosis and reliability research of the system.

• Asian Journal of Innovation and Policy
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• v.9 no.2
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• pp.133-144
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• 2020

Korean economy has experienced a very rapid growth largely due to the change of the innovation system since the last half century. The recent outbreak of COVID-19 impacts the global economy as well as Korea's innovation system. In order to understand the influence of the shock to the Korean technological system, we have forecast the future of the system combining qualitative and quantitative techniques such as expert panel, cross impact analysis, and scenario planning. According to the results, we have identified 39 driving forces influencing the change of Korea's technological innovation system. Four scenarios have been suggested based on the predetermined factors and core uncertainties. In other words, uncertainties of emergence of the regions and global value chains generate four scenarios: regional growth, unstable hope, returning to the past, and regional conflicts. The 'regional growth' scenario is regarded as the most preferable, whereas the 'regional conflicts' scenario is unavoidable. In conclusion, we put forward some policy implications to boost the regional innovation system by exploiting the weakened global value chains in order to move on to the most preferable scenario away from the return to the past regime.

• World Technopolis Review
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• v.1 no.1
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• pp.16-26
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• 2012

Many scientists today say that converged technologies, not specifically dedicated technologies, will be in the vanguard in the $21^{st}$ century. Technological Convergence is the merging of different areas of technology to perform similar tasks. Since we are living in the era of Technological Convergence, it is time for us to think about how to cope with the daily demands we are facing in science parks. Technological Convergence is a mega trend in commercial areas today but, so far, no science parks seem to have tried to reshape their management policies or programs in order to utilize this trend. For the development of science parks we suggest some tasks such as: identify potentials for Technological Convergence, establish a convergent ecosystem by building connections across stove-piped systems, effect a technological convergence platform, and conduct further research for strengthening plans for converging technologies.

• Proceedings of the Technology Innovation Conference
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• 2005.02a
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• pp.140-157
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• 2005

Industrial technological competitiveness is the major issue for many countries. therefore, many experts have concerned with how to measure competitiveness of industrial technologies. The purpose of this paper was to suggest the reasonable methodology of investigating competitiveness of industrial technologies. For such reasons, the technological competitiveness should analyzed on national, industrial an d firm level. In Korean case of the technological competitiveness has been assessed and analyzed industrial vision or target and looking for industrial demand survey for growing industries or requiring to investment of a large scale in dimension, such as 'Growing Engine Industries for Next Generation' However, it has not made a. thorough and systematic study on the assessment and analysis of the technological competitiveness, on this account developing of a systemic method and taking proper process of the technological competitiveness in industrial sector, and buildup the database system in adoptable real firms in sector. This paper will provide political counterproposal by surveying, assessing, and analyzing for technological competitiveness objectively through it can be leaded by technological innovations.

• Asian Journal of Innovation and Policy
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• v.10 no.1
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• pp.90-107
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• 2021

This paper analyses how technological capabilities and entrepreneurship of technology-based start-ups affect their performance. In this paper, a multiple regression analysis was conducted on 248 technology-based start-ups. The effects of indicators of technological capacity like R&D intensity, R&D organization, technology competitiveness, patents, and certification were analyzed. Factors affecting sales were R&D intensity and technological competitiveness. Technology competitiveness and patents were the significant factors influencing product competitiveness. The factor that positively influenced organizational performance, customer performance, and achievement of start-up goals was technological competitiveness. The results of such an analysis should be designed to discover and foster long-term innovation potential, rather than relying on short-term financial performance.

• Journal of Korea Society of Digital Industry and Information Management
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• v.12 no.3
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• pp.33-54
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• 2016

In the modern society based on information and communication, which is exposed to the risks of a lot of information security breaches, corporate information assets may be an economical scale in a country. Most of damages derived from corporate technological information leak often occur in small and medium corporations. Although many information security managers in corporations have focused on certification systems such as information security management system, small and medium corporations are poorly aware of the information security, and their environments surrounding it should be also improved. In addition, it is difficult to expect spontaneous participations in it, since the sustainable information security management systems are often not forced to be certified. Thus, the purpose of this study is to examine plans to improve small and medium corporations' technological protections by using some component of the information security management system. On the basis of this examination, it also attempts to discuss some methods for effective and efficient information security in the small and medium corporations' technological protections.

• Journal of the Optical Society of Korea
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• v.17 no.5
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• pp.357-361
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• 2013

A regenerative Er-doped fiber amplifier system for a high-repetition-rate optical pulse train is investigated for the first time. A signal pulse train with a wavelength tuning range of 18 nm is produced by a passive mode-locked fiber laser based on a nonlinear polarization rotation technique. In order to realize the amplification, an optical delay-line is used to achieve time match between the pulses' interval and the period of pulse running through the regenerative amplifier. The 16 dB gain is obtained for an input pulse train with a launching power of -30.4 dBm, a center wavelength of 1563.4 nm and a repetition rate of 15.3 MHz. The output properties of signal pulses with different center wavelengths are also discussed. The pulse amplification is found to be different from the regenerative amplification system for CW signals.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.34 no.4
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• pp.106-113
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• 2011

Human resource theories of becoming entrepreneurs or self-employed rather than finding employment are compared as applied to fit the occupational data of technological entrepreneurs and technology jobs. The human capital theory posits that technological entrepreneurs are prepared to become a jack-of-all-trades with a variety of fields of education. Hobo theory of entrepreneurship assumes that entrepreneurs have strong taste against concentrating on a few activities, which tend to drive entrepreneurs away from employed jobs depressing their expected income. Another theory assumes that entrepreneurs have some unobserved productive qualities and abilities over employed people. Immigrant entrepreneurs could presumably be pressured out of employment under racial discrimination. Since technology jobs are mostly filled by those educated in the science and technology fields, and they presumably offer great reward to professional concentration, technological entrepreneurs may not benefit from becoming jacks-of-all-trades compared to finding employment in technological jobs income-wise. Asian immigrants in the 2000 US Census data are compared to white immigrants in technological jobs to test alternative human resource theories of entrepreneurship. Using English language ability as a proxy for the variety of education, I find in the white immigrant technological entrepreneurs support for the jack-of-all-trades theory, while in the Asian immigrant technological entrepreneurs hobo theory is supported. In the Asian technological workers only there appears the significant self-selection or comparative advantage component, while at the same time discriminatory components are significant.

• Journal of Ocean Engineering and Technology
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• v.15 no.4
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• pp.80-85
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• 2001

The early construction of the internet based ship basic planning supporting system based on the concurrent engineering and the internet technology is essential as a means for the improvement of technology and design productivity our ship building industry is facing currently. Further more, technological base construction for the construction for the construction of the cooperation system on the level of ship building industry is necessary for the technological base security to maintain and develop ship building industry continuosly in the 21st century of the information industry environment and for the technological improvement of the middle and small shipyard falling behind relatively and finally for the breaking through our ship building industry environment in which inter-enterprise competition is deeping. In this study, we designed the frame-system of the ship design supporting system and presented the development scenario based on core element technology.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2009.01a
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• pp.429-434
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• 2009

We introduce an instant and intuitive shadowing technique for CACAni System. In traditional 2D Anime, since all frames are drawn by hand it takes long time to create an entire animation sequence. CACAni System reduces such a production cost by automatic inbetweening and coloring. In this paper, we develop a shadowing technique that enables CACAni users to easily create shadow for character or object in the image. The only inputs required are sequences of character or object layers drawn in CACAni System with alpha value. Shadows are automatically rendered on a virtual plane based on these inputs. They can then be edited by CACAni users. Achieving this, CACAni System is able to handle instant shadowing and intuitive editing in a short time.