• 제어로봇시스템학회:학술대회논문집
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• 1999.10a
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• pp.198-201
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• 1999

An automated storage and retrieval machinery for high rack warehouse systems is developed in order to stack the various kinds of productions. However, according to increase in the rack height, the long lead time should be taken. In stacker crane systems, the variations of the lifting height and the load generate the vibration of lifting machine, and it makes a Position control to be difficult Therefore, the reduction of vibration will be important factor for saving the lead time and the damage of Productions. This paper deals with a position control of stacker crane in automated high rack warehouse system by using a gain-scheduled control algorithm via a LMI method, where the variations of elastic coefficient of the stacker crane's post are considered.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.05a
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• pp.465-468
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• 2001

An objection of this study is to develop a high stable analytic system of radioactive pulses. The proposed system consists of an amplifying circuit with 60dB gain, a programmable power supply unit which can generate DC voltage up to 1, 500V, and a digital signal processor. Pulse height distribution in accordance with pulse counts is important data in analyzing radioactive pulses. In this study, AD convertor (12bit, l00ns) and DSP (TMS 320C31-60) are used to analyze the pulse height, and the analytic system is designed to be operated in PC-networking.

• Steel and Composite Structures
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• v.37 no.2
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• pp.137-150
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• 2020

In this research work, the analytical rotating vibration for functionally graded shell with ring supports are restricted to some volume fraction laws based on Rayleigh-Ritz technique. The frequencies of functionally grade cylindrical shells have been investigated for the distribution of material composition of material with two kinds of material. Stability of a cylindrical shell depends highly on these aspects of material with ring supports. The frequency behavior is investigated with fraction laws versus circumferential wave number, length-to-radius and height-to-radius ratios. The frequencies are higher for higher values of circumferential wave number. The frequency first increases and gain maximum value with the increase of circumferential wave mode. Moreover, the effect of angular speed is also investigated. It is examined that the backward and forward frequencies increases and decreases on increasing the ratio of height- and length-to-radius ratios.

• Proceedings of the IEEK Conference
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• 2004.08c
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• pp.653-657
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• 2004

The average bit error rate (HER) performance of a Gray coded arbitrary rectangular quadrature amplitude modulation (AR-QAM) signal with maximal ratio combining (MRC) diversity in an arbitrarily correlated Nakagami-m fading channel is derived and analyzed. The derived two types of general solutions are a simple closed-form and an integral form, depending on the types of the values (integer and non-integer) of the fading parameter. Using the derived equations in this paper, we analyzed the HER performances numerically based on the practical base station antenna configuration. The results show that MRC reception is a very effective scheme so far even though the combined signals are not independent each other because of the correlation values. The antenna height and separation of the MRC system relate to the correlation coefficient value between antennas, and go a long way with the diversity advantage. In particular, it is needed to be determined the antenna height that is carefully do for the diversity advantage because the correlation coefficient and the antenna height gain are contrary to each other from the aspect of the system performance. The expressions presented here can offer a convenient way to evaluate the exact HER performance of an arbitrary rectangular QAM signal with MRC diversity reception for various cases of practical interest on a correlated Nakagami fading channel.

• International Journal of Highway Engineering
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• v.14 no.4
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• pp.125-131
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• 2012

PURPOSES : Road lighting facilities increase the visibility of road at night in order to improve traffic driver safety and comfort. Generally speaking, current pole lighting has a tendency to create problems of glare and flicker. The phenomenon of glare gives discomfort due to increase of scattered light, when high luminance is in driver's field of view. The phenomenon of flicker occurs due to the driver passing through discontinuous pockets of pole lighting areas. These phenomenon increase eye strain and decrease driver safety. METHODS : Low height line lighting that distributes light lower than driver's eye level has been developed and evaluated to reduce the problems linked to current pole lighting. A test was undertaken with 4 conditions(turn on the general pole lighting, turn off alternate pole lighting, turn on the line lighting and line lighting with 50% dimming). A driver written survey was conducted in order to gain driver feedback. RESULTS : Pupil size and brow frequency compared with degree in pole lighting are reduced. CONCLUSIONS : Low height line lighting environment makes drivers more comfortable than pole lighting environment and is positive lighting method in the energy saving and landscape aspect.

• Transactions of the Korean Society of Automotive Engineers
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• v.9 no.4
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• pp.176-183
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• 2001

It is difficult to find out the kinematic characteristics of a vehicle suspension without the usage of CAE software. The application of CAE software into suspension kinematics and dynamics yields the more precise knowledge on the chassis design. In this study, the influence of the suspension geometry on the handling performances of a large-sized bus is investigated using the DADS software. The front and rear suspension of a large-sized bus are a rigid axle suspension with the four control links. The elastokinematic analysis is performed to evaluate the roll characteristics of the front and rear suspension. The elastokinematic responses are evaluated in terms of the roll center height and roll steer for various geometric parameters. The roll center height is mainly dependent on the vertical displacement of a panhard rod and the vertical displacements of lower control links affect the roll steer of a rear suspension. The parameter study with the change of rear suspension geometry is conducted to investigate the vehicle handling performances. This parameter study shows that the vertical displacement and orientation of a panhard rod influence the handling performances of a large-sized bus significantly.

• Journal of the Microelectronics and Packaging Society
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• v.26 no.2
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• pp.55-58
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• 2019

Surface plasmon effect was considered importantly because of the enhancement of optical signals. It is important to detect weak optical signal in neuroscience and bio technology due to detect weaker image or signal. The height of silver can change the optical characteristic of plasmonic nano structure including transmittance and reflectance. In this paper, the optical characteristic of plasmonic nano structure were confirmed by the FDTD analysis method depending on the silver height and it was confirmed that energy was concentrated at the center of nano structure, and high far-field gain and current density in particular wavelength coule be obtained.

• Advances in concrete construction
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• v.13 no.3
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• pp.223-231
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• 2022

The problem is formulated by applying the Kirchhoff's conception for shell theory. The longitudinal modal displacement functions are assessed by characteristic beam ones meet clamped-clamped end conditions applied at the shell edges. The fundamental natural frequency of rotating functionally graded cylindrical shells of different parameter versus ratios of length-to-diameter and height-to-diameter for a wide range has been reported and investigated through the study with fractions laws. The frequency first increases and gain maximum value with the increase of circumferential wave mode. By increasing different value of height-to-radius ratio, the resulting backward and forward frequencies increase and frequencies decrease on increasing height-to-radius ratio. Moreover, on increasing the rotating speed, the backward frequencies increases and forward frequencies decreases. The trigonometric frequencies are lower than that of exponential and polynomial frequencies. Stability of a cylindrical shell depends highly on these aspects of material. More the shell material sustains a load due to physical situations, the more the shell is stable. Any predicted fatigue due to burden of vibrations is evaded by estimating their dynamical aspects.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.231-232
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• 2008

The proposed cavity-backed slot antenna is comprised of baffles, reflectors and thick ground plane. The baffles and reflectors are used to increase an antenna gain, thus reducing the coupling among slots on a thick ground plane. The height of the baffle and reflector were altered and the characteristics of corresponding $2{\times}2$ cavity-backed slot array antennas were measured separately. Themeasured antenna gains were above 15dBi, at f=42GHz and a wide impedance bandwidth over 27% at a center frequency of 42GHz.

• Journal of Periodontal and Implant Science
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• v.43 no.2
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• pp.58-63
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• 2013

Purpose: The aim of this study was to measure the peri-implant bone length surrounding implants that penetrate the sinus membrane at the posterior maxilla and to evaluate the survival rate of these implants. Methods: Treatment records and orthopantomographs of 39 patients were reviewed and analyzed. The patients had partial edentulism at the posterior maxilla and limited vertical bone height below the maxillary sinus. Implants were inserted into the posterior maxilla, penetrating the sinus membrane. Four months after implant insertion, provisional resin restorations were temporarily cemented to the abutments and used for one month. Then, a final impression was taken at the abutment level, and final cement-retained restorations were delivered with mutually protected occlusion. The complications from the implant surgery were examined, the number of failed implants was counted, and the survival rate was calculated. The periimplant bone lengths were measured using radiographs. The changes in initial and final peri-implant bone lengths were statistically analyzed. Results: Nasal bleeding occurred after implant surgery in three patients. No other complications were found. There were no failures of the investigated implants, resulting in a survival rate of 100%. Significantly more bone gain around the implants (estimated difference=-0.6 mm, P=0.025) occurred when the initial residual bone height was less than 5 mm compared to the >5 mm groups. No significant change in peri-implant bone length was detected when the initial residual bone height was 5 mm or larger. Conclusions: This study suggests that implants penetrating the sinus membrane at the posterior maxilla in patients with limited vertical bone height may be safe and functional.