• International Journal of Internet, Broadcasting and Communication
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• v.9 no.1
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• pp.64-70
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• 2017

In the commercial building such as huge enterprise building, more accurate operation of the center-controlled roller blind. We design, in this work, the target disc that its shape is nonlinearly changing and the sensor coils that are differentially arranged. The performance shows less than 1% accuracy when it is implemented in the roller blind.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.101-102
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• 2006

Similar to Orthogonal Frequency Division Multiplexing (OFDM), a Single Carrier with Frequency Domain Equalization (SC-FDE) system is computationally efficient since equalization is performed on a block of data in the frequency domain. In coherent QAM schemes, the mean phase rotation error caused by the residual carrier frequency offset may lead to serious degradation. When the frequency equalizer is combined with the mean phase error tracking algorithm, its performance can be enhanced noticeably.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.4
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• pp.795-802
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• 1992

A numerical analysis is performed on the turbulent flow in the plain seal with injection. The parameters used in this study are as follows : Reynolds number, rotation speed, injection speed, clearance ratio, injection angle, and axial injection location. Flow pattern and leakage performance due to the variation of parameters are investigated. SIMPLER algorithm is used to solve the Navier-Stokes equation governing steady, incompressible turbulent flow and standard K- .epsilon. turbulent model is used to consider the turbulence effects. The leakage performance is significantly enhanced with injection. The increases of the injection flow rate and be rotation speed of the shaft cause the leakage performance to the increased. With the increase of the Reynolds number the leakage performance is diminished. At the injection angle of 90deg, the leakage coefficient has a minimum value. The pressure drop has a maximum value at axial center location but the injection location has little effect on the pressure drop. Clearance ratio has a significant effect on the pressure drop.

• Journal of Power Electronics
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• v.9 no.1
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• pp.74-84
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• 2009

The design and implementation of a high performance PID (Proportional Integral & Differential) style controller with zero-phase error tracking property is considered in this article. Unlike a ball screw driven system, the controller in a direct drive system should provide a high level of tracking performance while avoiding the problems due to the absence of the gear system. The stiff mechanical element in a direct drive system allows high precise positioning capability, but relatively high tracking ability with minimal position error is required. In this work, a feasible position controller named 'Unified PID controller' is presented. It will be shown that the function of the closed position loop can be designed into unity gain system in continuous time domain to provide minimal position error. The focus of this work is in two areas. First, easy gain tunable PID position controller without speed control loop is designed in order to construct feasible high performance drive system. Second, a simple but powerful zero phase error tracking strategy using the pre-designed function of the main control loop is presented for minimal tracking error in all operating conditions. Experimental results with a s-curve based position pattern commonly used in industrial field demonstrate the feasibility and effective performance of the approach.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.6 s.183
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• pp.96-103
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• 2006

To establish of standard technique of nano-length measurement in 2D plane, new AFM system has been designed. In the long range (about several tens of ${\mu}m$), measurement uncertainty is dominantly affected by the Abbe error of XY scanning stage. No linear stage is perfectly straight; in other words, every scanning stage is subject to tilting, pitch and yaw motion. In this paper, an AFM system with minimum offset of XY sensing is designed. And XY scanning stage is designed to minimize rotation angle because Abbe errors occur through the multiply of offset and rotation angle. To minimize the rotation angle optimal design has performed by maximizing the stiffness ratio of motion direction to the parasitic motion direction of each stage. This paper describes the design scheme of full AFM system, especially about XY stage. Full range of fabricated XY scanner is $100{\mu}m\times100{\mu}m$. And tilting, pitch and yaw motion are measured by autocollimator to evaluate the performance of XY stage. As a result, XY scanner can have good performance. Using this AFM system, 3um pitch specimen was measured. The uncertainty of total system has been evaluated. X and Y direction performance is different. X-direction measuring performance is better. So to evaluate only ID pitch length, X-direction scanning is preferable. Its expanded uncertainty(k=2) is $\sqrt{(3.96)^2+(4.10\times10^{-5}{\times}p)^2}$ measured length in nm.

• Journal of the Korean Society of Hazard Mitigation
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• v.7 no.1 s.24
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• pp.11-20
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• 2007

The study proposes the method to cancel the scallop to avoid fracture of the circumstance of the scallop at H shape column-to-beam connection and reinforce at beam flange two faces with the cover plates and rib. A total of four specimens were tested to enhance seismic performance of building structure by reducing the frequency of stress concentration and preventing the brittle fracture of scallop. For this purpose, four full-scale test specimens were made and loaded with quasi-static reversed cyclic loading. The main analytical parameters are panel-zone-strength ratio, yield strengths, initial stiffness, total plastic rotation, contribution of each element to total plastic rotation and energy dissipation capability. For the specimens tested under repeated loading, the experimental result was satisfied with seismic performance requirement as the Special Moment Frames (SMF). The analysis results show that all of the test specimens were found to have good performance to 4% story drift and satisfied the criteria for the plastic roation capacity of SMFs that is 0.03 rad. according to the 1997 AISC seismic provision.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.11a
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• pp.385-386
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• 2008

Dynamic stability of the vehicle rearview mirror is an important factor for the driver's visual perception (image blur) when driving down the road and regarded as one of the vehicle level N&V performance of visible component vibration. Several projects within GM identified a set of objective metrics and validation methods that can replace current existing subjective evaluation of mirror stability. This paper presents objective evaluation results for assessing dynamic stability (angle of rotation) of the vehicle rearview mirrors using both in-lab FRF measurements and on-road testing.

• Proceedings of the Korea Multimedia Society Conference
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• 2000.04a
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• pp.449-452
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• 2000

This paper proposes a new, adaptive Dead Reckoning model, called Dynamic Dead Reckoning , for Distributed Interactive Simulation and humanoid avatar systems. The proposed model can overcome the weak points of traditional Dead Reckoning caused by a fixed threshold and strong dependency on rotation event. This paper introduces new criteria for update message filtering , named as Update lifetime. The Dynamic Dead Reckoning keeps the balance between extrapolation fidelity and filtering performance by two component models, Variable Threshold Mechanism and Rotation Event model. The experimental results show that the proposed model can lower the increment rate of update traffic to the increase of rotation frequency without any significant loss of accuracy.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.05a
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• pp.688-691
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• 2004

This study summarizes results of a research project aimed at investigating the inelastic rotation capacity of beam-column joints of reinforced concrete moment frames. A total of 28 specimens were classified as special moment frame connections based on the design and detailing requirements in the ACI 318-99 provisions. Then, the acceptance criteria, originally defined for steel moment frame connections in the AISC-97 Seismic Provisions, were used to evaluate the joint connections of concrete moment frames. Twenty seven out of 28 test specimens that satisfy the design requirements for special moment frame structures provided sufficient strength and are ductile up to a plastic rotation of $3\%$ without any major degradation in strength.

• The Journal of Korea Robotics Society
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• v.5 no.4
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• pp.326-331
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• 2010

Marionette controlling robot has a problem that generates interference in rotation and intersection, therefore, the research on the independent shifter to move freely on the stage is required. Connecting omni-directional mobile robot with marionette controlling robot can solve this problem. Omni-directional mobile robot makes itself rotate and translate in 2D plane freely. Magnetic device is used to connect the moving part with the control part of the robot to minimize the intereference generated by the movement of robot. When robot moves, it can move to all directions with the suitalbe setting of banlance power. The moment of inertia is minimized by dividing the robot to the upper and lower parts in the marionette performance stage. Rotation and interference problem of independent omni-wheel Robot can be solved by using the permanent magnet. The efficiency and safety of the marionette controlling robot is proved by the experiment.