• The Journal of the Korea Contents Association
• /
• v.14 no.9
• /
• pp.120-130
• /
• 2014

The purpose of this study was to evaluate the effects of line dance activity on the balance factors during static standing to reveal the exercise intervention for fall prevention. A 15-week line dance programme was applied to 16 elderly females who aged more than 65 years in the community. Balance ability during static standing was evaluated by the range of center of pressure(cop), the velocity of cop, and sway area that calculated on the basis of ground reaction force data, forces, and moments. The range and velocity of cop in the anterio-posterior were significantly reduced after line dance(p<.01, p<.05, respectively), but change in those of cop in the medio-lateral was not found. It was demonstrated that 16-week line dance activities allow more effective in anterio-posterior stability and sway area of static standing. It was suggested that the effect of fall prevention exercise should be studied more associate with fall from vestibular and sensory system as future study.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.9 no.2
• /
• pp.301-306
• /
• 2005

In this paper, a gain-boosting charge pump(CP) and a latch type voltage controlled oscillato.(VCO) with voltage controlled resistor(VCR) were proposed. The gain-boosting CP achieves good .current matching of less than 11$mu$V voltage difference between 43$mu$V and 32$mu$V in its output range from 0.8V to 2.3V. The VCO with VCR shows good linear characteristics over the range from 1V to 3V. The fabricated VCO exhibits -108dBc/Hz phase noise at a 100kHz and is comparable to that of the integrated LC-tank oscillator. The phase locked loop(PLL) with new circuits was simulated in a 0.35$mu$m CMOS process and showed 150$mu$s locking time.

• Journal of Korea Society of Industrial Information Systems
• /
• v.19 no.2
• /
• pp.59-66
• /
• 2014

AGV is most often used for the automation of freight transportation in the manufacturing industry or the distribution warehouses. AGV is fairly costly and used in goods transport between the determined location. The main control device dedicated to AGV is often autonomously developed for simplification using PLC in industry field. However, AGV developed for simplification makes many errors in traffic because it is developed for the limited simple function. Control device dedicated to AGV has been developed to solve the problem but it is almost impossible to revise the device according to the character and structure of every manufacturing industry. The purpose of this study is to propose the design method of the control system interlocked with PLC and dedicated to AGV. The control system should be to improve the problem of traffic rolling and possible to be revised according to the character of factory. It is apparent the proposed AGV system is efficient in operation in the result of several traffic performance analysis through the tests.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 1994.10a
• /
• pp.9-16
• /
• 1994

In the discrete optimum design, occasionally, the solutions oscillate between the feasible and the infeasible resions during the series of redesigns of members with discrete sections. This phenomenon may be caused inherently by the discontinuity of variables of commercially available sections in the database. In this paper, in-depth investigation into the oscillation in the discrete optimization and its control has been conducted. When the structure is optimized through element optimization, the oscillation can be divided into two categories, local and global oscillations. An algorithm which controls these phenomena is suggested and numerical examples demonstrate the oscillation in optimum solutions and the effectiveness of the control strategy suggested here.

• Korean Journal of Optics and Photonics
• /
• v.8 no.5
• /
• pp.362-365
• /
• 1997

This paper presents a new optical phase stabilization technique for interferometric such as Mach-Zehnder interferometers or Homodyne detectors. The proposed technique can lock such interferometric systems in their maximum/minimum optical outputs without using a dither signal. The phase control scheme is a modified steepest decent algorithm, and is analyzed in terms of a delta modulation approach. It is also applicable to low-repetition rate pulsed interferometric systems in which conventionally used dithering method is difficult to be applied.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.14 no.3
• /
• pp.164-169
• /
• 2006

A systematic methodology has been proposed to establish a reliable design of water pump system. A simplified steady-state dynamic model of water pump system has been developed to study the response of water pump system to the dynamic load mainly due to the run-out and unbalance. Design modifications are needed to strengthen the structural integrity of existing designs. Increasing the natural frequency of system is pursued to prevent a resonance from occurring in the engine excitation range. A computational reliability methodology combined with finite element analysis is used to identify the most significant factor affecting the system performance. This method considered influence of design control parameters for the performance of design. By including control factors to the system model in a systematic way, more reliable design is expected.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.62 no.3
• /
• pp.407-413
• /
• 2013

This paper proposes anti-swing control of overhead crane system using sum of squares method. The dynamic equations of overhead crane include nonlinear terms, which are transformed into polynomials by using Taylor series expansion. Therefore the dynamic equation of overhead crane can be changed to the system of polynomial equation. On the basis of polynomial dynamics of crane system, we propose the Sum of Squares (SOS) conditions considering the input constraints. In addition, control gains are obtained by numerical tool which is called by SOSTOOL. The effectiveness of the proposed method is demonstrated by numerical simulation.

• Proceedings of the KIEE Conference
• /
• 1996.07b
• /
• pp.977-979
• /
• 1996

This paper presents an algorithm to control the undesirable sway of a suspended load in the crane system that has a trade-off between positioning the load and suppressing the sway of the load. The aim is to transport the load to a specified place with small sway angle as quickly as possible. Dynamic model is based on a simple pendulum driven by a velocity drive that is mostly used for actuating a trolley in industry. Proposed algorithm is composed of two parts : one is a off-line optimal trajectory generator, the other on-line tracking control. The former produces optimal trajectories minimizing energy under the speed constraint of velocity drive. The latter controls outputs to track the generated trajectories. Digital simulations and experiments are performed on a pilot crane to demonstrate the performance of the proposed control algorithm.

• Proceedings of the KIEE Conference
• /
• 2005.07b
• /
• pp.1465-1467
• /
• 2005

In this paper, the harbor container crane which transports containers between a container ship and trucks in the harbor is modeled. The equation of motion is simplified for control purpose. The pole placement technique is used to control the crane to minimize load swing angle The objective of the control is to transfer the load as quickly as possible, while minimizing the amplitude of swing at the end of transfer. Computer simulations are provided.

• Journal of Drive and Control
• /
• v.16 no.3
• /
• pp.1-7
• /
• 2019

The reach truck, which is mainly used in warehouses, is required to have high-mast to improve its working efficiency and space utilization. The high-mast takes advantage of more vertical space but severe vibrations are easily generated at the end of the high-mast. These vibrations may cause a collision or misplacement of loading location at work. In this study, the vibration characteristics of a three-stage high-mast of a reach truck are analyzed, and an active vibration controller verified through a similar experiment is designed to reduce this vibration. A similar experiment for reach truck mast verifies the performance of the active vibration controller. By applying an active vibration controller designed for a real reach truck, the operations of the reach truck are made more efficient through the reduction of the vibration amplitude.