• The Inventors News
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• no.4
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• pp.6-6
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• 2002

`2002 전국학생 발명상상화 및 캐릭터 그리기 대회` 수상자 결정 - MS, 익스플로러 특허 소송 위기 - 외국 제품 모방 출원 요령 - `컬러링` 특허 논란 일고 있다 - 주5일 근무제 확산에 따른 레저용품 출원 증가

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.1083-1084
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• 2011

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.87-88
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• 2011

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.8
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• pp.264-273
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• 2013

The importance of the robots has emerged as the means of minimizing the casualties in the future war, and, thus, the biomimetic robots mimicking the optimized organisms has been actively studied. The robot inspired lizard is suitable for reconnaissance and the surveillance in narrow areas. In this paper, we analyzed the locomotion of a lizard by motion capture system using the infrared markers. We attached 21 markers to the joints of the lizard. By considering the measured data, we analyzed the walking motion of the lizard which trots in a sprawled posture. Moreover, we proposed the 25 dof kinematic model which was able to reproduce the gait of the lizard faithfully. The model was verified by simulations.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.12
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• pp.1069-1078
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• 2013

In this paper, we propose a distributed time synchronization technique for OFDMA- based wireless mesh communication systems. The proposed technique employs the bio-inspired algorithm for self-time synchronization in the physical layer. To achieve the network synchronicity, the proposed technique updates the transmission time and the FFT window using the TDoA information of received signals from the neighbor nodes. The proposed technique can achieve fast self-synchronization among nodes with a simple algorithm, without the need of a centralized controller. The performance of the proposed time synchronization technique is evaluated by simulation in terms of convergence speed and convergence probability.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.12
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• pp.611-620
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• 2016

Firms grow in a competitive environment and competition can be a source of corporate growth. In an increasingly global market, companies face increased competition. As such, it is natural that all firms face some degree of risk due to competition. While firms compete for market share, they also imitate competitors in order to minimize risk that accompanies competition. This research attempts to demonstrate the effects of inter-firm competition on investment decisions. Using idiosyncratic equity returns as the instrument variable, this paper uses a two-stage least squares regression, as well as an ordinary least squares (OLS), to identify the influence of peer firms' investment decisions on a firm's own investment strategy. The results confirm that firms show stronger imitative behavior with more intense competition. Also, firms with higher debt ratios show higher peer group influence. This imitative factor provides clues to measure the risk-averseness in investment decisions.

• Informatization Policy
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• v.22 no.4
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• pp.91-104
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• 2015

This study tests the effects of differential association, definitions, differential reinforcement and imitation from social learning theory in the explanation of university students' crimes in social network services. In addition, this study tests the interaction effects between social learning factors and other factors such as low self-control, subcultural environment, and crime opportunity for the integrated approach. Using data from 486 university students in Seoul, results show that both definition and imitation have significant influences on crimes, even though differential association and differential reinforcement factors have no significant influences on crimes in social network services. Results also reveal that there are significant interaction effects between definition and subcultural environment, which meana that definition has a strong effect on crimes in high subcultural environment. In addition, it is found that reinforcement has also a strong effect on crimes in high crime opportunity and that interaction effect between imitation and low self-control is significant, which means that imitation has a strong effect on crimes in low self-control students.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2007.11a
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• pp.311-314
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• 2007

Aerodynamic characteristics of an insect-type flapping wings were carried out to obtain the design parameters of Micro Hovering Air Vehicle. A pair of wing model was scaled up about 200 times and applied two pairs of 4-bar linkage mechanism to mimic the wing motion of a fruit fly(Drosophila). To verify the Weis-Fogh mechanism, a pair of wings revolved on the 'Delayed Rotation'. Lift and drag were measured in conditions of the Reynolds number based on wing tip velocity of about 1,200 and the maximum angle of attack of 40$40^{\circ}$. Inertia forces of a wing model were also measured by using a 99.98% vacuum chamber and subtracted on measured data in air. In the present study, high lift effect of Weis-Fogh mechanism was appeared in the middle of upstroke motion.

• Journal of the Korea Society of Computer and Information
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• v.19 no.1
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• pp.181-189
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• 2014

The purpose of this study is to suggest some policy implications for the youth through empirical study about the effects of middle school students' brand perception on their sociability. For the purpose of this study, this study established a causal model about the relationships between brand perception and sociability through review of previous studies and surveyed for empirical research. The results of this study are presented as follows: Preference, imitation, and relevance as brand purchase elements of teenagers affected their self-esteem and empathy for others significantly. Self-esteem that is meditating variable in this study did not have a significant effect on sociability, while empathy for others had a great effect on it. This study suggested policy implications for teenagers to have good standards and a sense of value in a brand purchase.

• Journal of Advanced Navigation Technology
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• v.21 no.5
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• pp.450-458
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• 2017

This paper presents dynamic modelling and simulation study on attitude/altitude control of an insect-mimicking flapping micro aerial vehicle during hovering. Mathematical modelling consists of three parts: simplified flapping kinematics, flapping-wing aerodynamics, and six degree of freedom dynamics. Attitude stabilization is accomplished through linear quadratic regulator based on the linearized model of the time-varying nonlinear system, and altitude control is designed in the outer loop using PID control. The performance of the proposed controller is verified through numerical simulation where attitude stabilization and altitude control is done for hovering. In addition, it is confirmed that the attitude channel by periodic control is marginally stable against periodic pitching moment caused by flapping.