• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.6
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• pp.1145-1154
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• 2018

In order to prevent interference and interference of the frequency, it is required to convert the regulatory standard into the center of the radiation power radiated to the actual public. Since the radiation power regulation is related to general radio management such as technical standards, permits, and inspections, it is gradually introduced in consideration of applicability and urgency, and the radiation power related laws of major countries And a method of controlling the output of the radio equipment such as measurement, inspection, and authentication. In Korea, the proportion of antenna power supply is high, and in Europe, radiation power is high. Since the number of radio stations will increase and diversify in the future, institutional improvement should be made so that it can be measured in parallel with the radiocommunication infrastructure of the space manager. In order to convert to the radiative power management system, the system for the related radio system needs(Technical standards, certification, inspection of radio stations, post-management, etc.) to be improved.

• Journal of the Earthquake Engineering Society of Korea
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• v.11 no.4
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• pp.25-31
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• 2007

For areas such as the Korean Peninsula, which have moderate seismic activity but no available records of strong ground motion, synthetic seismograms can be used to evaluate ground motion without waiting for a strong earthquake. Such seismograms represent the estimated ground motions expected from a set of possible earthquake scenarios. Local site effects are especially important in assessing the seismic hazard and possible ground motion scenarios for a specific fault. The earthquake source and rupture dynamics can be described as a two-step process of rupture initiation and front propagation controlled by a frictional sliding mechanism. The seismic wavefield propagates through heterogeneous geological media and finally undergoes near-surface modulations such as amplification or deamplification. This is a complex system in which various scales of physical phenomena are integrated. A unified approach incorporates multi-scale problems of dynamic rupture, radiated wave propagation, and site effects into an all-in-one model using a three-dimensional, fourth-order, staggered-grid, finite-difference method. The method explains strong ground motions as products of complex systems that can be modified according to a variety of fine-scale rupture scenarios and friction models. A series of such deterministic earthquake scenarios can shed light on the kind of damage that would result and where it would be located.

• Journal of the Society of Naval Architects of Korea
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• v.55 no.4
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• pp.281-288
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• 2018

Acoustic radiation efficiency is a crucial factor to estimate Underwater Radiated Noise (URN) of ships accurately. This paper describes a numerical method to analyse acoustic radiation efficiency of one side-wetted rectangular Mindlin plate with simply supported boundaries excited by a harmonic point force. Transverse displacements of plate and acoustic radiation pressures are evaluated by the mode superposition method. The acoustic radiation efficiencies analyzed by both Mindlin and thin plate theories show little differences at monopole and corner modes of low frequency regions but relatively large differences at edge and critical modes of high frequency regions. Especially, the critical frequency with the highest acoustic radiation efficiency evaluated by the Mindlin plate theory is higher than that of thin plate theory. In addition, the acoustic loading effect of fluid also increases bending wave-number of plate and its critical frequency. Finally, the acoustic radiation characteristics of plates with different aspect ratios and thicknesses through numerical analyses are investigated and discussed.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.6
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• pp.1289-1295
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• 2015

Electromagnetic wave signals radiated from an antenna are reflected by targets and received through the same antenna. These received signals show different characteristics according to various target materials having different dielectric constants. Therefore, target characteristics can be recognized if we can utilize these return signals efficiently. this method can be applied for discrimination and classification of hazardous materials. In this paper, utilizing these experimentally obtained signals, correlation characteristics are obtained and analyzed for classification and discrimination purposes. Although the correlation method requires the storage of reference signals, it shows very promising results. this correlation method can be applied for classification and discrimination of hazardous materials.

• Steel and Composite Structures
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• v.28 no.5
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• pp.629-639
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• 2018

In this paper, the vibroacoustic responses of baffled laminated composite sandwich flat panel structure under the influence of harmonic excitation are studied numerically using a novel higher-order coupled finite-boundary element model. A numerical scheme for the vibrating plate has been developed in the frame work of the higher-order mid-plane kinematics and the eigen frequencies are obtained by employing suitable finite element steps. The acoustic responses are then computed by solving the Helmholtz wave equation using boundary element method coupled with the structural finite elements. The proposed scheme has been implemented via an own MATLAB base code to compute the desired responses. The validity of the present model is established from the conformance of the current natural frequencies and the radiated sound power with the available benchmark solutions. The model is further utilized to scrutinize the influence of core-to-face thickness ratio, modular ratio, lamination scheme and the support condition on the sound radiation characteristics of the vibrating sandwich flats panel. It can be concluded that the present scheme is not only accurate but also efficient and simple in providing solutions of the coupled vibroacoustic response of laminated composite sandwich plates.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.5 no.2
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• pp.20-28
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• 1994

Theoretical radiation patterns for the corrugated horn antenna are analyzed by vector integral method and quasi-optics. The formular of the radiated fields for the corrugated horn antenna can be obtained by the potentials derived the equivalent current sources from hybrid fields at horn aperture and also calculated by the expanded mode set of Gaussian - Laguerre based on the quasi - optics. From comparison of the radiation patterns between two methods for a corrugated horn antenna designed on 85-115 GHz frequency range, the results are coincided well at center frequency but have some errors at each side frequencies 85 and 115 GHz.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.5
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• pp.1573-1581
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• 1996

This paper present as experimental demonstratio of DSP and a sensory actuator that is used to actively control sound transmission/radiation through a vibrating plate. A plane acoustic wave incident on a clamped, thin circular plate was used as a noise source, and a sensory actuator bounded to the plate was used to control and sense vibration of the plate. The sound transmission reduction problem was tranformed as a structural vibration control problem that actively control the structural vibration modes coupled to acoustic modes. The results show that the first structural vibration mode is controlled with a reduction of 78 percent in the displacement and velocity of the plate. This corresponds to a 13dB reduction in the acoustic response. These experimental results indicate that a sensory actuator bounded to the plate can be employed to attenuate the sound transmitted to radiated from the plate.

• The Journal of Korean Physical Therapy
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• v.13 no.3
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• pp.561-567
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• 2001

IR classified by wavelength three parts NIR, MIR. FIR. There is FIR which is radiated from healthy human body the wave length is 8-14m. The Sun's ray is composed of Infared(49%), Visible light(40%) and Ultra violet(11%), however the ray getting to the earth is FIR(60%), IR(20%), and UV(20%). Human beings has utilized FIR already from time immemorial. Hershel found out Infrared for the first time, in the Industrial Revolution the Infrared and FIR had been begun to use making products. FIR with low temperature can deeply penetrate on the human body composed things without troublesome, since FIR has effectively operated on the human body at low temperature (35-40 $^{\circ}$C). In this study, we experimented in the specific temperature FlR radiation intensity. water consumption rate, feed consumption rate. survival rate and mean of weight balance with FlR radiation instrument. According to the results, the FlR radiation to the mice assisted to increase the survival rate.

• The Journal of Korean Physical Therapy
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• v.13 no.1
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• pp.189-195
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• 2001

The Sun's ray is composed of Infared(49%), Visible light(40%) and Ultra violet(11%), however the ray getting to the earth is FIR(60%). IR(20%), and UV(20%). Human beings has utilized FIR already from time immemorial. Hershel found out Infrared for the first time, in the Industrial Revolution the Infrared and FI R had been begun to use making products. In asia. also, asian already has made use of FIR to treat the body, product things and make warm the house in the winter, as it had been called Wull therapy, fermentation. and On-Dol system. In these days, with contemporary science FIR would be begun to clear up the implication in the human body and organic compounds. IR classified by wavelength three parts NIR, MIR, FIR. There is FIR which is radiated from healthy human body the wave length is 8-14 m. It is difficult to standardized the wavelength of IR, since each related associations have a different opinion, so we suggested ideal IR wavelength and biological, phsiotherapical, medical FIR wavelength.

• Journal of the Korean Society for Nondestructive Testing
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• v.16 no.4
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• pp.241-250
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• 1997

The velocity dispersion of surface acoustical wave(SAW) of Si layer/mesh Au/Si substrate was measured by the frequency analysis technique of backward radiation at liquid/solid interface. The difference of backward radiation patterns depending on used transducers (2, 5, 10MHz) confirmed that the backward radiation phenomenon was caused by the energy radiation from SAW generated in surface region. An ultrasonic goniometer was constructed to measure continuously the angular dependence of backscattered intensity. The angular dependences of backward radiation(5MHz) were measured for Ni layer/Al substrate specimens that were bonded by epoxy involving different content of Cu powder. It was known that the width and pattern of backward radiation had informations such as the velocity dispersion, bonding quality and structure of surface region.