• Tunnel and Underground Space
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• v.20 no.5
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• pp.318-324
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• 2010

Dynamic properties of materials by shock loads such as rock blasting and earthquake are recently attracted in the design of aboveground and underground structures. The advance of measuring devices enables to obtain the whole histories of stress and strain in rock specimen of which the failure is completed in several hundred microseconds. The SHPB has been a popular and promising technique to study the dynamic behavior of rock. And the dynamic compressive, tensile and other test with this experiment system are planned to be Suggested Methods of ISRM. This technical paper is to introduced one study article which focuses the design of 3S (special shaped striker) to produce the half-sine wave to eliminate the problems of the rectangular wave. This article is also describing the advantage of half-sine incident wave and size effect of rock dynamic strength.

• The korean journal of orthodontics
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• v.24 no.4 s.47
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• pp.897-916
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• 1994

The biologic potential, which is different from the piezoelectric signals, relates tooth movement at least in part to changes in bone metaboliosm in bioelectric theory. The purpose of this experiment was to determine wheather the application of half sine-wave pulsed electromagnetic fields (HSPEMF) could increase both the rate and amount of orthodontic tooth movement. Forty-three male Hartley guinea pigs, weighting approximately 255g, were utilized in this study. The animals were 35 days old at the start of the study. Laterally directed orthodontic force was applied to the maxillary central incisors of 40 Hartley guinea pigs (20 experimental, 20 control). According to the amount of orthodontic force (6g, 12g), they were divided into two sub-groups (10 experimental I, 10 experimental II, 10 control I, 10 control II). During the experimental period, experimental animals were placed in plastic animal holders with their heads positioned in an area of uniform electromagnetic field. Control animals were placed in similar plastic holders that did not carry the electric apparatus. The results were as follows : 1. The application of a HSPEMF to the experimental groups significantly increase the final amount of orthodontic tooth movement observed over a 10-day experimental period. 2. The application of a HSPEMF to the experimental groups significantly increase the velocity of orthodontic tooth movement observed over a 10-day experimental period. 3. There was no significant difference in the final amount of orthodontic tooth movement at the fourth day to the eighth day, but there was significant difference in the final amount of orthodontic tooth movement at the nineth, tenth day during a 10-day experimental period. 4. After 10 days of HSPEMF exposure & orthodontic force, the experimental groups demonstrated more osteodasts in the pressure side than control groups.

• The korean journal of orthodontics
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• v.29 no.2 s.73
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• pp.157-163
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• 1999

The purpose of this study was to investigate the effect of electromagnetic field in orthodontic tooth movement, and the optimal application period of electromagnetic field to initiate tooth movement. Eighty male Hartley guinea pigs were utilized in this study. Laterally directed orthodontic force was applied to the maxillary central incisors. Half sine-wave pulsed electromagnetic field(HSPEMP) was applied to experimental group during 10 days. According to the period of application of HSPEMP(4 hours, 8 hours, 12 hours a day), they were divided into the three sub-groups The obtained results were as follows; 1. In case of application of HSPEMF during 4 hours a day, there was no significant difference in the final amount of orthodontic tooth movement between the experimental and the control group. 2. In case of application of HSPEMF during 8 and 12 hours a day, there was a significant increase in the final amount of orthodontic tooth movement since the eighth day, the sixth day respectively. 3. In comparison with the case of application of HSPEMF during 8 hours a day, there was a significant increase in the final amount of orthodontic tooth movement at the seventh day and the eighth day in case of application of HSPEMF during 12 hours a day.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.9 no.5
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• pp.51-56
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• 1995

The transistors of single phase 3 level PWM Inverter compose output power transistors and neutral point clamping transistors, which are NPN transistors. Waveforms of driving signals for this are PWM waves for power transistors and period operating waves for neutral point clamping transistors, which signals made W-type modulation from rectangular and sine wave. The output power transistors operate at ON-time complementary and neutral point clamping transistors operate at OFF-time complementary respectively. Therefore, each transistors operate in half period at parallel. Characteristics of this inverter circuit is parallel switching method about series switching method of general inverter. As modulation of 3 level drive signals made from full-wave rectifier of sine wave and rectangular wave, which are level wave about 3 level of complementary transistor inverter. So, this circuit composed complementary operation inverter of NPN transistors only compare with PNP-NPN complementary inverter, which have high power 3 level inverter of complementary operation.

• Advances in Computational Design
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• v.1 no.4
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• pp.357-370
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• 2016

This paper aims to examine the dynamic response of a newly designed ultrasonic motor under half-sine shock impulses. Impact shock was applied to the motor along x, y or z axis respectively with different pulse widths to check the sensitivity of the motor to the shocks in different directions. Finite Element Analysis (FEA) with the ANSYS software was conducted to obtain the relative displacement of a key point of the motor. Numerical results show that the maximum relative displacement is of micro meter level and the maximum stress is five orders smaller than the Young's modulus of the piezo material, which proves the robustness of the motor.

• Proceedings of the KIEE Conference
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• 2000.07b
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• pp.1327-1329
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• 2000

The thyristor among the power-semi-conductor elements, which has large current capacity and high voltage, is used widely nowadays. When the thyristor was being used to the long time, this element may be able to arise the system trip caused by changing the characteristic and dropping the performance. Therefore, it would be necessary to analyze the characteristic of element to maintain the stable operation of the system. In oder to analyze this characteristic, it would be need to test forward direction, reverse direction and leakage current by supplying the half-sine wave voltage. Among these testing, transient current condition is generated from the testing of leakage current. This transient current may be the main factor of the error in the precise measurement of leakage current. Therefore, this paper analyzes the relationship between supply voltage and transient current in measuring leakage current of the SCR, and then suggests the condition and cause of transient current as appearing the leakage current in the testing the leakage current.

• ETRI Journal
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• v.35 no.5
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• pp.739-747
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• 2013

This paper investigates the multifarious nature of the long-term evolution (LTE) scheme and that of the modified LTE scheme for symbol timing synchronization (STS). This investigation allows us to propose a new replica correlation-based STS scheme to overcome the inherent weaknesses of the other two schemes. The proposed STS signal combines a gold sequence and a half sine wave in the time domain, whereas conventional STS signals specify either binary sequences or complex sequences in the time domain or in the frequency domain. In the proposed scheme, a sufficient correlation property is realized by the gold sequence, and robustness against the frequency offset (FO) is achieved through the sine wave. Compared to the existing LTE-related schemes, the proposed scheme can better achieve immunity to FO and reduction in detector complexity, as well as a low peak-to-average power ratio and a low detection error rate. Performance evaluations through analysis and simulation are provided in the paper to demonstrate these attributes.

• Proceedings of the KIEE Conference
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• 2001.11c
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• pp.334-337
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• 2001

In this paper we implemented DDFS and gam-phase dectector which use output of DDFS or any sinusoidal signal input to broaden the usability of DDFS. DDFS is composed of a 32 bits phase accumulator, phase increment registers, ROM and several registers for controlling the operations. It generates the digital data for sine wave up to the half of the clock frequency. To reduce the ROM size and increase the speed, we adopt the algorithms based on Taylor's series expansion method. Data at sparse phase intervals are stored in ROM and sine data between intervals are calculated in hardware. Function of Gain-Phase Extraction consists of sine lookup of DDFS and the optimized multipliers.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.39 no.2
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• pp.157-163
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• 1990

The PWM inverter investigated in this paper utilizes a bridge type current sharing reactor circuit with tow pairs of complementary transistor at each phase. The driving signals for this inverter are 3 level PWM waves of W type an M type modulation, which are obtained from a microprocessor based on the switching time data obtained by switching position calculation of triangular and sine modulation wave. The output voltage waveforms of this inverter have 5 level phase voltage and 9 level line voltage of PWM. The harmonics of the output voltage are reduced to half when it is compared with single CTI, and the occurrence of harmonics is also reduced.

• Journal of Multimedia Information System
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• v.9 no.3
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• pp.233-244
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• 2022

A MATLAB program was developed to calculate the half-wavelength of a sine-curve baseband signal with white noise by using an autocorrelation function, a SG filter, and zero-crossing detection. The frequency of the input signal can be estimated from 1) the first zero-crossing (corresponding to ¼λ) and 2) the R value (the Y axis of the correlogram) at the center of the segment. Thereby, the frequency information of the preceding segment can be obtained. If the segment size were optimized, and a portion with a large zero-crossing dynamic range were obtained, the frequency discrimination ability would improve. Furthermore, if the values of the correlogram for each frequency prepared on the CPU side were prepared in a table, the volume of calculations can be reduced by 98%. As background, period detection by autocorrelation coefficients requires an integer multiple of 1/2λ (when using a sine wave as the object of the autocorrelation function), otherwise the correlogram drawn by R value will not exhibit orthogonality. Therefore, it has not been used in bio-telemetry where the frequencies move around.