• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.46 no.12
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• pp.1012-1020
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• 2018

In order to improve the capability of mission flight of tiltrotor UAV that has been developed by Korea Aerospace Research Institute, a simulation study on the formation flight of autonomous control 5 level has been performed. The formation flight is based on the centralized method with leader and follower airplanes. The formation flight controller was verified through numerical simulation with 3 followers and hardware-in-the loop simulation with 1 follower. This paper describes controller design methods, hardware-in-the-looped simulation test, and performance verification using simulation.

• Journal of Digital Convergence
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• v.13 no.10
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• pp.107-120
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• 2015

In this paper, we study the conflict management plan of the organization in the age of convergence. More specifically, we reveal the impact of the conflict according to behavior of the leader. To this purpose, The behavior of the leader were classified as Supportive Leader and Controlled Leader, and forms of Resistance wert classified as Functional Resistance and Dysfunctional Resistance that results of the conflict. Also, Psychological Contract Violation and Breach was set up as a mediate variable. The results were as follows. First, When employee resistance comes up in the organization, Support behavior of Leaders leads to desirable changes in the organization through the functional and constructive resistance. In contrast, Controlled behavior of Leaders leads the destructive and dysfunctional resistance of employee. Second, Since the perception that the follower is receiving assistance to leaders, it reduces the perception of psychological contract violation, but Controlled leader is largely perceived as the Psychological Contract Violation to the followers. Third, Supportive Leader is not influence the affect of employee, and They resolve the Conflict in objective and positive way. Therefore, the results of this study have many theoretical and practical implications.

• Journal of Technology Innovation
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• v.13 no.1
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• pp.247-263
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• 2005

Prior research in R8ED innovation in Korea has been centered around the 'three-stage development model,' which hypothesizes that the Korean innovation process goes from the introduction (of foreign technology) stage, through assimilation stage to the final modification stage. As Korean economy shifts from traditional industry-led development to innovation-centric development, such an approach loses sight of the whole picture. The current study argues that a new framework is required for adequate analysis on newly arising innovative patterns in Korea, emphasizing source technology development and technology leader strategy. For this purpose, we propose the 'Jigsaw Puzzle Model' of technology development, which is then verified by an in-depth analysis on the innovation processes of 3 representative IT products of Korea, DRAM, TH LCD, and CDMA. The model suggests that Korean innovation model is a dynamic, efficient amalgamation of foreign-acquired and dependent technologies, based on internally accumulated technological resources. The model explains better how Korean firms are achieving a rapid catch-up of technological gaps with advanced nations and are able to transfer from the technology follower to the leader position.

• Journal of the Korean Society for Precision Engineering
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• v.31 no.11
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• pp.1023-1030
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• 2014

This paper presents a new method to control swarm robots so that they can keep the formation while following a curved path. The main idea is to utilize the information on the instant center of gyration. For a given path, location of the instant center of the formation center is calculated, and individual robots follow the circular path around the calculated instant center. Performance of curvature-radius based method is compared with leader-follower referenced method via MATLAB simulation.

• International Journal of Aeronautical and Space Sciences
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• v.14 no.2
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• pp.183-192
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• 2013

This paper presents formation reconfiguration using impulsive control input for spacecraft formation flying. Spacecraft in a formation should change the formation size and/or geometry according to the mission requirements and space environment. To modify the formation radius and geometry with respect to the leader spacecraft, the follower spacecraft generates additional control inputs; the two impulsive control inputs are general control type of the spacecraft system. For the impulsive control input, Lambert's problem is modified to construct the transfer orbit in relative motion, given two position vectors at the initial and final time. Moreover, the numerical simulation results show the transfer trajectories to resize the formation radius in the radial/along-track plane formation and in the along-track/cross-track plane formation. In addition, the maneuver characteristics are described by comparing the differential orbital elements between the reference orbit and transfer orbit in the radial/along-track plane formation and along-track/cross-track plane formation.

• Bulletin of the Korean Space Science Society
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• 2003.10a
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• pp.41-41
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• 2003

Satellite formation flying is currently an active area of research in the aerospace engineering. There are many categories for this research such as the determination of initial conditions, formation keeping, configuration and reconfiguration. In this study, a tracking controller using sliding mode techniques is designed to control a satellite for the satellite formation flying. In general, Hill's equations are used to describe the relative motion of the follower satellite with respect to the leader satellite. But, the modified Hill's equations considering J2 perturbation were used for the design of sliding mode controller. Sliding mode control law causes the chattering phenomenon because it is a discontinuous control. Dead-zone was used to avoid the chattering. The Extended Kalman filter was applied to estimate the state vector based on the measurements of relative distance and velocity between two satellites.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.165-166
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• 2008

Bistatic spotlight synthetic aperture radar(BSSAR) with single track configuration uses the transmitter and the receiver which travel along the single track such as the leader-follower. For the BSSAR imaging, we modify the range migration algorithm. In time domain, we make the monostatic SAR using shifting of path, Then, in frequency domain, we compensate the separated distance between the scene center and the flight path using the principle of the stationary phase (PSP).

• Journal of the Korean Society of Costume
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• v.37
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• pp.89-102
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• 1998

This paper has main purpose of identifying the difference of the characteristicss of male consumers who have different levels of fashion leadership. 538 male consumers living in Seoul area was surveyed using questionnaire. Sam-ples were surveyed using questionnaire. Sam-ples were segmented as 3 groups by fashion leadership and named fashion leader, fashion follower and fashion retards. Various character-isticss in terms of personality, attitudes, life-estyle activities, magazined readership, use of fashion information sources, shopping behavior, risk perception and demographics analysis among 3 segments. 3 groups showed significant differences in many characteristics such as venturesomeness, cosmopoliteness, ex-tensity of travel, art/culture activity for offtime, reading of male-oriented magazines, in-formation search through fashion magazine, fashion knowledged, shopping preferrence, clot-hing expense. Based on major characteristics of each segment, some tips for marketing strategies were suggested.

• Journal of Institute of Control, Robotics and Systems
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• v.9 no.12
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• pp.994-1000
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• 2003

A new relative motion control methodology for a following system to an independent leading system is proposed for controlling relative position, velocity, and tension etc. It is based on maintaining minimum relative error between two independent systems. The control command of the following system to a leading system is generated by adding the current command and the output of the relative error compensation. The proposed control method is implemented on the experimental equipment which is a wire winding-unwinding system to control the tension of the line. The results show the unwinding system(follower) following the independent motion of the winding system(leader) to control the constant tension of the line in order to keep the roller dancer in reference position. The relative motion control method proposed in this paper can be applied to high precision equipment for unwinding and winding fine wire, fine fiber, and tape etc.

• Journal of Fisheries and Marine Sciences Education
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• v.28 no.1
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• pp.127-136
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• 2016

The purpose of this research is to conduct a comparative study on the characteristics of daily volatility spillovers across the stock markets of Korea, China, and Japan. We employ generalized spillover definition and measurement developed by Diebold & Yilmaz (2009, 2012). The sample period is January 5, 1993 to September 25, 2015. From a static full-sample analysis, we find that 8.60% of forecast error variance comes from volatility spillovers. From a 250-day rolling-sample analysis, we discover that there exist significant volatility fluctuations in the stock markets of Korea, China and Japan, expecially during the Asian Financial Crisis (1998-1999) and the US Credit Crisis (2008-2009) after the collapse of Lehman Brothers. From the net directional spillovers across three countries, we come upon that there is neither a definite leader nor a significant follower during the sample period.