• Journal of the Korean Chemical Society
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• v.23 no.3
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• pp.125-131
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• 1979

A method for calculation of two center overlap integrals for a pair of Slater type orbitals was developed by Mulliken et al. In this method the spherical polar coordinates for a pair of Slater type orbitals located at two different points are required to be transformed into a spheroidal coordinate set for calculation of two center overlap integrals. A new method, the expansion method for spherical harmonics, in which Slater type orbitals, located at two different points, are expressed in a common coordinate system has been applied for computation of two center overlap integrals. The new method for computation of two center overlap integrals is required to translate Slater type orbitals centered at two different points into the reference point for computation of two center overlap integrals. This work has been expanded the expansion method for spherical harmonics for computation of two center overlap integrals to $|3s{\g}$, $|5s{\g}$ and $|5s{\g}$. Master formulas for two center overlap integrals are derived for these orbitals, using the general expansion formulas. The numerical values of the two center overlap integrals evaluated for a hypothetical NO molecule are in agreement with those of the previous works.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.32B no.10
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• pp.1280-1285
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• 1995

In this paper the optimized overlap driving scheme for improving the reduction problem of the operating voltage range occured by the overlap driving scheme proposed precedently and increasing the contrast ratio of screen image in the simple matrix LCDs is proposed. The characteristic estimation of the proposed method was performed in a condition that the number of scan electrodes was 120 and the threshold voltage of LC pixel was 2V and the overlap rate of scan signal was varied from 0% to 40% . As a result of estimation compared with the overlap driving scheme proposed precedently, this new method was certified as a method which it could increase the operating voltage range of the LC pixel by 16% in 20% overlap condition and it's operating voltage range was also increased very much with the increase of the overlap rate. Consequently this newly proposed method was certified as a method which it could maintain the improvement effect of the operating characteristics obtained by the overlap driving scheme proposed precedently with the big improvement in the contrast ratio of screen image.

• Journal of Power Electronics
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• v.18 no.2
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• pp.615-626
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• 2018

To ensure a DC current path and avoid large voltage overshoot of the DC-link inductor, alternating PWM pulses in the current-source rectifier should be supplemented by overlap time, which generates an overlap current and causes input current distortion. In this study, the influence of overlap time is illustrated by comparing the AC-side current before and after overlap time is added. The overlap current distribution caused by overlap time is discussed under different modulation carriers, including triangle carrier, positive-going carrier, and negative-going carrier. The quantitative relationship between the extra harmonics of the AC-side current and overlap time is based on the Fourier analysis. Based on the commutation analysis, a new carrier modulation scheme that can restrain overlap current is proposed. A 3 kW prototype is established to verify the effectiveness of the influence of overlap time and the proposed restraining modulation scheme.

• Journal of radiological science and technology
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• v.43 no.3
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• pp.161-167
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• 2020

This study aimed to found out the effect of patellofemoral overlap distance by changing femur thickness and center X-ray angles in Merchant method images. Based on the femur thickness, it suggested tube angle minimizes overlap. It was conducted by Merchant method, a knee tangential view, and the image was obtained by changing the thigh thickness from 14 to 20 cm and the center ray angle from 60°, 57°, 55°. The images were measured by five researchers using a method of measuring the overlap, which was designed by them. The results showed at 60°, 57°, 55° angle, the patellofemoral overlap distance resulted in 0.47±0.66 to 20.89±0.65 cm, 2.26±0.28 to 15.73±0.62 cm, 1.39 ± 0.83 to 12.49 ± 0.37 cm. However, for 57° and 55°, no overlap in thickness under 14.5 and 14 to 15.5 didn't appear. it showed high correlation between femur thickness and overlap. The difference in the mean value of overlap in each group showed a statistically significant difference (p<0.01), all were classified as independent groups in the post-hoc test. In all images, the patellofemoral overlap distance increased as the thickness increased, and at the average thickness of Korean men and women, overlap decreased when reducing center ray. When conducting Merchant tests on Koreans, it was suggested it would be useful to use 57° angle because it minimize the effects of overlap and intrusions of tibia.

• Journal of Korean Society for Atmospheric Environment
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• v.25 no.5
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• pp.450-458
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• 2009

The range-dependent overlap factor of a lidar system can be determined experimentally if a Raman backscatter signal by molecule is measured in addition to the usually observed elastic backscatter signal, which consists of a molecular component and a particle component. The direct determination of the overlap profile is presented and applied to a lidar measurement according to variation of telescope field-of-view and distance between telescope and transmitting laser. The retrieval of extinction coefficient by Raman method can generate high errors for heights below planetary boundary layer if the overlap effect is ignored. The overlap correction method presented here has been successfully applied to experimental data obtained in Gwangju, Korea.

• The Journal of the Acoustical Society of Korea
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• v.19 no.8
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• pp.35-46
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• 2000

In this paper, we propose a subband acoustic echo canceller using the weighted Overlap-add adaptive filter bank to prevent the decrease of convergence speed in full-band US processing, and make it possible to realize the adaptive filter in block-parallel processing, this paper introduces the weighted overlap-add technique for subband echo canceller. Moreover, we propose a new double-talk detector which employs dedicated filter in addition to the energy comparison method simultaneously. The computer simulation results show that the performance of the proposed subband adaptive echo canceller double-talk detection

• Journal of the Korean Chemical Society
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• v.22 no.3
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• pp.117-127
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• 1978

Slater type orbitals, located at two different points A and B, are expressed in a common coordinate system by expanding the spherical harmonics and the radial part of these orbitals in terms of the reference point A. Master formulas for two center overlap integrals are derived, using the general expansion formulas of slater type atomic orbitals. Two center overlap integrals for $CH_4,\;H_2O,\;NH_3,\;C_2H_6\;and\;PH_3$molecules are evaluated, using master formulas for two center overlap integrals. The results are in agreement with those of two center overlap integrals of Mulliken.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.26 no.2
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• pp.205-213
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• 2017

In order to improve occupant protection in frontal crash, the IIHS introduced a small overlap frontal crash test in 2012. When the front corner of a car collides with another car or object, such as utility pole the test replicated the sequence of events. Because occupants move simultaneously forward and toward the side of the vehicle this test is challenging for some airbag and safety belt designs. In the small overlap frontal test, a car travels at 64 km/h toward a rigid barrier. A hybrid III dummy is positioned in the driver seat. 25% of the total width of the car strikes the barrier on the driver side. After review of small overlap frontal test protocol and overall rating, six run-throughs were performed according to the original test method.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.31A no.7
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• pp.110-116
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• 1994

In this paper a Duty Effective Overlap Scanning method (DEOS) for the improvement of driving efficiency of LC displays which have the RMS voltage responding characteristics is proposed and new processing method of data signals for optimum application of this method is also proposed. Proposed method has a few advantages such as the increment of duty ratio the increment of driving power loaded on LC cell and the decrement of RMS voltage error rate caused by signal attenuation on electrodes composing of display when compared with the conventional method which is called as optimum voltage amplitude selection method. And also by adopting new data signal processing method which has 3 kinds of voltage levels additional advantage much improving crosstalk phenomenon which is the most serious problems of simple matrix structured display is obtained. For the characteristic estimation new mathematical representation for new overlap scanning method and data signal processing method are induced and defined. And by the defined formula and simulation the characteristics of the proposed method and the conventional method are compared and analyzed. As a result of estimation this new method being able to optimize the overlap rate of scan signal and using 3 levels of data signals has the characteristic which can improve the driving efficiency of LC displays.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.35 no.8
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• pp.661-669
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• 2007

Study on the feasibility assessment for applying the overlap grid method to numerical calculations on the ground effect has been performed. The objective of the present study is to settle the problem in the grid generation process. A low Mach number preconditioned turbulent flow solver using the overlap grid and the multi-block grid methods has been developed and applied to the ground effect simulation around the RAE 101 airfoil. It has been verified that the overlap grid method not only can provide sufficiently accurate solutions but also work out the grid generation problem in the ground effect simulations.