• Journal of Korea Society of Industrial Information Systems
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• v.18 no.6
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• pp.9-16
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• 2013

Bio-impedance measurement system(BMS) is non-invasive and easy to implement a measurement method that allows determining the water content of a patient. The measurement conditions, the hardware specifications and the configurations of BMS devices must be well chosen in order to get correct and reproducible results. BMS was then conducted for the limbs and the thoracic using a lock-in amplifier and LabView control system with a frequency range of 1kHz-100kHz. From both the measurement data and the simulation results, we verified that the parameters in the proposed equivalent model and the trend of impedance variation according to the multi-frequency of applied current source are similar to those of human body. We believe that the real-time BMS developed in this study is highly reliable and applicable to the research on the clinical characteristics of the human being's impedance.

• Journal of the Institute of Convergence Signal Processing
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• v.11 no.2
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• pp.157-162
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• 2010

In this paper we propose a fractal analysis based on the discrete wavelet transform. It is well known that Fourier Transform is widely used for frequency analysis of random signal. However, the frequency domain is not used for expressing the sudden signal change and non-stationary signal at the time-axis by this method. Maximum value in the wavelet modules can be expressed by the Lipschitz exponent, which is useful to represent the characteristics of signal or the edge of an image. It is possible to reconstruct the original image only by using the few maximum points. The v possible image It iusing oil was acquired to interpret the maximum value. ufter that, it was applied to the v possible image of a ship model. In addition, the fractal dimens by by the conlapse process of the sediment particle was examined. In this paper, the fractal dimens by has been obtained by the maximum value and the experiment obtained from the visualized image also acquired the same result as existing methods.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.2
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• pp.385-394
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• 2021

In this paper, a new equation of electromagnetic wave transmission matrix was proposed to calculate the reflected power and transmitted power for the multi-layered planar lossy structure. The applied human leg was modeled as a four-layer planar structure of skin, fat, muscle and bone. The complex dielectric constant to consider the loss of each of these layers was calculated using the 4-pole cole-cole model parameter. When electromagnetic waves were incident on the skin surface, total reflected and transmitted power, and human body loss were calculated for a frequency band of 0.1 to 20.0 GHz. And for various muscle thicknesses, the power reflected only from the outermost bone and re-radiated from the skin was calculated. It was confirmed that at the muscle thickness of 3.0 mm and the frequency of 4.6 GHz the return loss was -6.13 dB, which was 3.42 dB lower than the average value.

• Korean Institute of Interior Design Journal
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• no.16
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• pp.3-9
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• 1998

The purpose of this research is to empirically validate the IIPS (Interior Image Preference Scale) which is a newly developed visual instrument for evaluating the environmental disposition inherent to individuals especially one's interior image preferences. The questionnaire survey was used. The data were collected from Oct. 10th 1997 to Nov. 14th 1997. The subjects were 399 undergraduate students and 30 professor of Dep. of Interior Design. With respect to content validity and construct validity of IIPS discrimination and similarity structure of scales and characteristics of 12 prototype interior images were examined in comparison with the originals. 429 questionnaires were analyzed using frequency percentage mean and Multi-Dimensional Scales. The major results were as follows (1) All 80 items of IIPS were discriminated by 3 criteria such as Traditionalism·Modernity(TM) Masculinity·Femininty (MF) and Simplicity·Complexity (SC) as expected at the time of the instrument development stage.(2) 12 prototype interior images of the IIPS showed tendency to be accord with descriptors to express them in comparison with the originals (3) All 90 items of IIPS showed a cluster distribution according to the similarity structure of scales. Three subscales of IIPS(e . g. TM MF and SC) were structured pretty well by those 3 dimensions. This research revealed the IIPS to have content validity and construct validity for evaluating of preference of three properties of interior image in empirical research. The IIPS was found to be potential objective tool to measure the interior image preferences.

• Journal of the Korean Graphic Arts Communication Society
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• v.30 no.1
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• pp.21-33
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• 2012

This research attempts to analyze the effect of printed-saving coupons distributed by major discount store on consumer purchasing intention. Those consumers having used printed-saving coupon in major discount store in Daejeon were selected as respondents. 121 copies were retreated from 150 questionnaires. For data analysis, frequency analysis for respondents' characteristics, Cronbach's alpha for reliability of analysis, and $X^2$ test of multi-regression analysis for testing hypothesis were utilized. The result of analysis shows 1) the way of using coupon is respectively different according to sex, age group, marital status, term of coupon, and the number of using coupon; 2) Attributes of coupon partially influence on purchasing intention of consumers. Only shopping cost cutting is insignificant, while keeping convenience, impulse buying, scheduled purchasing are significant. The most effective variable is scheduled purchasing, keeping convenience, and impulse buying influence on purchasing intension of consumers. Therefore, offering printed-coupon by major discount store is useful tool to induce consumers to planned purchasing.

• Journal of the Korean Institute of Telematics and Electronics T
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• v.36T no.1
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• pp.79-85
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• 1999

The propagation properties of the high speed pulse signal in time domain using the equivalent circuits for the analysis by SPICE on the coupled microstrip lines are investigated. In this paper, the SPICE program is used for the crosstalk analysis on the coupled microstrip lines. The results of crosstalk of coupled microstrip lines compared to one by Branin and FDTD method. And the near-end and far-end crosstalk on coupled lines are analyzed for the square pulse and trapezoidal pulse. The results of this paper are apply To the determination for the geometric structure and the frequency of signal pulse in design of MIC and MMIC by the CAD program.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.1331-1334
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• 2004

The research on electromagnetic shielding has been advanced for military applications as well as for commercial products. Utilizing the reflective properties and absorptive properties of shielding material, the replied signal measured at the rear surface or at the signal source can be minimized. The shielding effect was obtained from materials having special absorptive properties or from structural characteristics such as stacking sequence. Recently researchers studied the electromagnetic properties of nano size particles. In this research {glass fiber}/{epoxy}/{nano particle} composites(GFR-Nano composites), was fabricated using various nano particles, and their properties in electromagnetic shielding were compared. For the visual observation of the nano composite materials, SEM(Scanning Electron Microscope) and TEM(Transmission Electron Microscope) were used. For the measurement of electromagnetic shielding, HP8719ES S-parameter Vector Network Analyser System was used on the frequency range of 8 GHz～12GHz. Among the nano particles, carbon black and Multi-Walled Carbon Nano-Tube (MWCNT) revealed outstanding electromagnetic shielding. Although silver nano particles (flake and powder) were expected to have effective electromagnetic shielding due to their excellent electric conductivities, test showed little shielding effect.

• 한국정보통신설비학회:학술대회논문집
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• 2007.08a
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• pp.390-393
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• 2007

The reliability as well as the power capability of the UPS system can be increased by replacing a single UPS unit with multiple small UPS units in parallel, resulting in a so-called module UPS. This module UPS system allows that a new module can be added or replaced while maintaining power to loads, which is a hot-swappable operation. In addition, it has desirable features such as ease of output power expandability, convenience of maintenance and repair, and high reliability. To realize the module UPS, load sharing without interconnection among parallel connecting modules as well as a small scale and lightweight topology is necessary. The frequency and voltage droop method is applied to parallel operation control to achieve load sharing. 5kVA modules are designed and implemented to confirm the effectiveness of the proposed approaches. Experimental results show that the module UPS system has a high power factor, a low distortion of output voltage and input current, hot-swappable operations and good load sharing characteristics.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.4
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• pp.667-672
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• 2003

Smart antennas will be used mon widely for the higher data rate and the larger number of users as the demand of wireless multimedia service is increased. Therefore, the BER performance is analyzed in this paper for DS-CDMA and MC-CDMA systems using smart antennas. A reverse link channel is simulated assuming the frequency selective Rayleigh fading. The simulation results are presented based on the characteristics of DS-CDMA and MC-CDMA systems according to the signal spectrum bandwidth and the method of adaptive beamforming. The BER performances of both systems are improved as the beam width of smart antennas is decreased. Also, it is shown that the performance of MC-CDMA system is much better than that of DS-CDMA system as the number of users is increased.

• Atmosphere
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• v.29 no.4
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• pp.463-480
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• 2019

This study classified heavy rain types from K-means clustering for the hourly relationship between rainfall intensity and cloud top height over the Korean peninsula, and then examined their statistical characteristics for the period of June~August 2013~2018. Total rainfall amount of warm-type events was 2.65 times larger than that of the cold-type, whereas the lightning frequency divided by total rainfall for the warm-type was only 46% of the cold-type. Typical cold-type cases exhibited high cloud top height around 16 km, large reflectivity in the upper layer, and frequent lightning flashes under convectively unstable condition. Phenomenally, the cold-type cases corresponded to cloud cluster or multi-cell thunderstorms. However, two warm-type cases related to Changma and typhoon were characterized by heavy rainfall due to long duration, relatively low cloud top height and upper-level reflectivity, and the absence of lightning under the convectively neutral and extremely humid conditions. This study further confirmed that the forecast skill of rainfall could be improved by applying correction factor with the overestimation for cold-type and underestimation for warm-type cases in the Local Data Assimilation and Prediction System (LDAPS) operational model (e.g., BIAS score was improved by 5%).