• Proceedings of the IEEK Conference
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• 2002.06d
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• pp.183-186
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• 2002

In this paper, we present an area-efficient programmable FIR digital filter using canonic signed-digit(CSD) coefficients, in which the number of effective nonzero bits of each filter coefficient is reduced by sharing the shift and add logics for common nonzero bits between adjacent coefficients. Also, unused shift and add logics for a low- magnitude coefficient are reassigned to an appropriate high - amplitude coefficient. In consequence, the proposed architecture reduces the hardware area of a programmable FIR filter by about 24% and improves performance about 6-7dB compared to other multiplierless FIR filters with powers-of-two coefficients.

• The Journal of the Acoustical Society of Korea
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• v.13 no.2E
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• pp.5-13
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• 1994

Simulation of the target-scattered echo requires the understanding of scattering mechanism at the highlight points. In this paper, the basic assumption of Highlight Model is reviewed through the analyzed data obtained in the acoustic water tank experiment. The analysis shows that the scattering mechanism involves pulse elongation and frequency shift as elements of target-scattered echo, and that the internal structures affect the temporal response of the target-scattered echo significantly. The band-limited impulse response or Green's function due to the diffraction from highlight points of internal structures is not mere delta function, but acts like a filter, which causes frequency shift and is elongated in time.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.2
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• pp.121-126
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• 2014

The problem of finding the fastest algorithm for multiplication of two large n-digit decimal numbers remains unsolved in the field of mathematics and computer science. To this problem so far two algorithms - Karatsuba and Toom-kook - have been proposed to shorten the number of multiplication. In the complete opposite of shorten the number of multiplication method, this paper therefore proposes an efficient multiplication algorithm using additions completely. The proposed algorithm totally applies shift-and-add algorithm of binary system to large digits of decimal number multiplication for example of RSA-100 this problem can't perform using computer. This algorithm performs multiplication purely with additions of complexity of $O(n^2)$.

• Proceedings of the IEEK Conference
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• 2001.06a
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• pp.209-212
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• 2001

We Propose a novel structure add/drop multiplexer based on an all-fiber Mach-Zehnder interferometer and fiber Bragg grating. In this structure, wavelength separation is achieved by adjusting the amount of the phase shift in the Mach-Zehnder interferometer. The proposed add/drop multiplexer drops a part of signal at a specific wavelength and transmit the remnant of the signal to the different node separated wavelength in WDM network.

• Journal of Preventive Medicine and Public Health
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• v.25 no.4 s.40
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• pp.374-385
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• 1992

Some circadian rhythms can become disorgnized due to rotating shift work. This lack of organization, termed desynchronization, can produce a group of symptoms such as insomnia, GI disturbance and fatigue among many rotating shift workers. The magnitude of these symptoms are influenced by personal and environmental factors and the patterns of shift work. This study was carried out to investigate the subjective symptoms related to rotational schedules of shift work after personal and environmental factors adjusted. 182 male workers in rapidly rotating shift system and 86 male workers in weekly rotating shift system were conducted the questionnaire on personal factors and subjective sleep, GI and fatigue symptoms. Major findings obtained from this study are as follows: 1. The symptoms of 'feeling tired at work' and 'being irritable' were more frequent in weekly rotating shift workers (P<0.05), and the mean of symptom score was significantly higher in weekly rotating shift workers(P<0.01). 2. According to 6 hours of sleeping which is a definite elevation point of fatigue, there was not a significant difference between two groups in sleeping hours. Among workers in rapidly rotating shift system, the mean of symptom score was significatly higher in workers of less than 6 hours of sleeping(P<0.05), but it was not different among weekly rotating shift workers. 3. The symptoms of GI disturbance were more frequent in weekly rotating shift workers but statistically not significant. 4. The positive rate of mental and physical fatigue symptoms were significantly higher in weekly rotating shift workers(P<0.01) and mental and physical fatigue symptoms were more frequent in them (P<0.01). 5. After the effect of the factors that were significantly different between two groups by $X^2-test$ were controlled, the mean score of sleep disturbance was significantly higher in weekly rotating shift workers (P<0.01) and mental physical fatigue symptoms were more frequent in them (P<0.01). Based on these study results, subjective symptoms were more common in the weekly rotating shift workers. In future, medical examination and laboratory test will be also administered to evaluate a more accurate health outcomes and the review of current shift schedules will be required.

• Journal of the Korea Institute of Military Science and Technology
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• v.16 no.2
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• pp.199-206
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• 2013

In general, radial velocity of a target can be obtained by acquiring doppler frequency shift in case of a doppler radar, or can be obtained by acquiring range rate in case of a pulse radar. Then radial velocity can be converted to tangential velocity using aspect angle or position variation per unit time. These two ways have the same meaning in physically, but result in different uncertainty finally. In this paper, it is described not only the two transformation procedures to calculate tangential velocity from radar measurement data, but also the result of combined uncertainty comparison between these two procedures.

• Journal of the Korea Institute of Military Science and Technology
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• v.12 no.5
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• pp.644-651
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• 2009

In this paper, the design results of a $22.5^{\circ}$ diode phase shifter for the RADANT lens and two $11.25^{\circ}$, $22.5^{\circ}$ dielectric phase shift layers for the diode phase shifter are presented. The amount of phase shift introduced by each dielectric layer depends on the thickness and the shape of the metal strip and the electrical property of the diode. The equivalent circuit model is employed to represent the dielectric phase shift layer, and the simulated result of the equival circuit model is compared with the result of the field simulation. The measured data of the fabricated $11.25^{\circ}$, $22.5^{\circ}$ dielectric phase shift layer shows about $2^{\circ}$ phase shift error.

• Journal of the Korean Society for Nondestructive Testing
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• v.27 no.1
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• pp.8-14
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• 2007

X-ray digital tomosynthesis is widely used in the nondestructive testing and evaluation, especially for the printed circuit boards (PCBs). In this study, we propose a simple method to reduce the blur artefact, frequently claimed in the conventional digital tomosynthesis based on SAA (shift-and-add) algorithm, and thus restore the image sharpness. The proposed method is basically based on the SAA, but has a correction procedure by finding blur artefacts from the forward-and back-projection for the firstly obtained, manipulated backprojection data. The manipulation is the replacement of the original data at the POI (plane-of-interest) by zeros. This method has been compared with the conventional SAA algorithm using the experimental measurements and Monte Carlo simulation for the designed PCB phantom. The comparison showed a much enhancement of sharpness in the images obtained from the proposed method.

• Journal of the Optical Society of Korea
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• v.12 no.3
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• pp.157-161
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• 2008

A wavelength-selective reflector, composed of a double-ring-resonator add/drop filter and a loop-back mirror at the drop port to be used for a hybrid-integrated tunable laser is designed and fabricated. High-index-contrast polymer waveguide is used to realize a compact device as small as $2mm{\times}0.4mm$. The radii of the rings are slightly different from each other to obtain a wide wavelength tuning via a vernier effect. Peak reflectivity is measured to be 52% for TE mode and polarization-dependent wavelength shift is 0.95 nm. The tuning range is measured to be about 42 nm for applied current as small as 46 mA.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.10
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• pp.59-68
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• 2013

This paper proposes the boost type bidirectional DC/DC converter with high efficiency for electric vehicle using an interleave method. This interleave method can reduce the system size because it reduces the ripple of output voltage and input current with no add to extra filter. Proposed system is consist of two converters and applies to interleaved method through phase shift to each converter. And it implements the high boost through voltage double and series construction of output port. Also, it reduces the price and increases the efficiency as operating the ZCS by leakage inductance of transformer and capacitor of voltage double with not add special reactor. Proposed DC/DC converter using interleave method is proved the validity through the result of PSIM simulation and experiment of 5kW DC/DC converter.