• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.30 no.6
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• pp.467-478
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• 2019

This paper describes the development and measurement results of a wide-band planar active phase array antenna system for an electronic warfare jamming transmitter. The system is designed as an $8{\times}8$ triangular lattice array using a $45^{\circ}$ slant wide-band antenna. The 64-element transmission channel is composed of a wide-band gallium nitride(GaN) solid state power amplifier and a gallium arsenide(GaAs) multi-function core chip(MFC). Each GaAs MFC includes a true-time delay circuit to avoid a wide-band beam squint, a digital attenuator, and a GaAs drive amplifier to electronically steer the transmitted beam over a ${\pm}45^{\circ}$ azimuth angle and ${\pm}25^{\circ}$ elevation angle scan. Measurement of the transmitted beam pattern is conducted using a near-field measurement facility. The EIRP of the designed system, which is 9.8 dB more than the target EIRP performance(P), and the ${\pm}45^{\circ}$ azimuth and ${\pm}25^{\circ}$ elevation beam steering fulfill the desired specifications.

• Journal of the Korean Society of Clothing and Textiles
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• v.28 no.910
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• pp.1300-1311
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• 2004

The aim of this study was to provide the 2 and 3 dimensional statistics requisite in the sizing system and design of gloves. The 64 2-dimensional static measurements were selected to provide information about hands. Participants in the study were 824 adults, aged between 18 and 64. To summarize the information from the measurement values, a Factor Analysis and a Cluster Analysis among multivariate analyses were performed. 3-D scanner was used for visual results of hand shape of each cluster. The results were as follows. Twenty-two items were used for the factor and cluster analysis in order to classify the adult hand shape. The variable quantities that are explained by a total of 3 factors amounted to under 79.37% of the variable quantities. The definition results of the factors related to the hands are as follows: Factor 1 is the horizontal dimension, the thickness of hand factor; Factor 2 is the height of the crotch; and Factor 3 is the vertical dimension of the hand. The adults' group hand was divided into 2 clusters according to a cluster analysis using factor scores. The characteristics according to hand type were as follows: Cluster 1 referred to high horizontal dimensions and thickness, rather small vertical dimensions and crotch height; and Cluster 2 represented the rather smaller horizontal dimensions and thickness but longer hand length than Type 1. To provide specific shape data of each cluster, 3-D scanner measurement was performed. 3-dimensional data base was developed for each cluster type and visual information was provided.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2015.11a
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• pp.8-10
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• 2015

최근 2D 와 3D 콘텐츠의 급격한 수요 증가로 인하여 2D 와 3D 공간에서 사람이 인지하는 물체의 시각적 정보량을 정량화할 필요성이 대두되었다. 본 논문에서는 정보이론에 기초하여 엔트로피 관점에서 2D 와 3D 영상의 시각적 정보량을 측정하는 방법을 제시한다. 시각적 정보량을 측정할 때, 기존의 연구에서는 고려되지 않았던 집중영역(saliency), 시각세포의 불균형으로 인한 주변영역 흐림현상인 포비에이션(foveation), 양안합성(binocular fusion)등 인간의 시각적 특성을 반영하였다는 점에서 기존의 연구들과 차이를 둔다. 2D 콘텐츠의 시각적 엔트로피는 단안시에 근거한 질감(texture) 엔트로피와 깊이 엔트로피로 구성되어 있다. 그리고 3D 콘텐츠의 시각적 엔트로피는 2D 에서의 시각적 엔트로피와 양안시에 의한 깊이 엔트로피를 포함한다. 본 논문의 시각적 엔트로피는 2D 와 3D 영상의 시각적 피로도를 측정할 때 사용될 수 있다.

• Applied Microscopy
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• v.52
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• pp.1.1-1.8
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• 2022

As semiconductor device architecture develops, from planar field-effect transistors (FET) to FinFET and gate-all-around (GAA), there is an increased need to measure 3D structure sidewalls precisely. Here, we present a 3-Dimensional Atomic Force Microscope (3D-AFM), a powerful 3D metrology tool to measure the sidewall roughness (SWR) of vertical and undercut structures. First, we measured three different dies repeatedly to calculate reproducibility in die level. Reproducible results were derived with a relative standard deviation under 2%. Second, we measured 13 different dies, including the center and edge of the wafer, to analyze SWR distribution in wafer level and reliable results were measured. All analysis was performed using a novel algorithm, including auto fattening, sidewall detection, and SWR calculation. In addition, SWR automatic analysis software was implemented to reduce analysis time and to provide standard analysis. The results suggest that our 3D-AFM, based on the tilted Z scanner, will enable an advanced methodology for automated 3D measurement and analysis.

• Transactions of Materials Processing
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• v.33 no.4
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• pp.285-290
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• 2024

Electropulsing treatment (EPT) has been developed as an alternative to furnace heat treatment (FHT) to exploit its engineering advantages in rapidly annealing metallic materials. Conventionally, the separation of thermal and athermal effects of EPT has been attempted by comparing EPT and FHT specimens processed under identical temperature and duration. However, this method inherently introduces experimental and measurement errors. This study proposes a novel approach to distinguish the thermal and athermal effects of EPT-processed metals using T-shaped specimen with two observation points, namely 'C' and 'D'. For verification, the thermal gradient of T-shaped Mg alloys was examined under various EPT conditions. The points C exhibited higher temperatures compared to those at points D at a given electric current density, because only the former received both thermal and athermal effects. It was confirmed from twelve specimens that the point C at an electric current density of 65 A·mm^-2 and point D at 70 A·mm^-2 exhibited similar temperatures. This developed method is expected to reduce measurement errors in distinguishing thermal and athermal effects, thus providing a deeper understanding of their quantitative contributions in future studies.

• Journal of Advanced Marine Engineering and Technology
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• v.38 no.4
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• pp.396-402
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• 2014

The measurement of air-borne noise in a naval ship is a crucial element. Because the noise in a naval ship interferes with a communication between crews and finally it causes to reduce the combat power. Thus, most of newly built ships have to satisfy the criteria of air-borne noise in the stage of delivery of a naval ship. In order to evaluate success or failure of criteria, uncertainty of the measurement should be considered. This study introduces the test method for the measurement of the air-borne noise in a naval ship and is concerned with the evaluation of uncertainty. The uncertainty results which was from the measurement of air-borne noise in 7 naval ships newly built satisfy the error tolerance(2dB). Therefore, it is need to reduce the error tolerance for the reliable measurement result.

• Journal of Biomedical Engineering Research
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• v.23 no.5
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• pp.397-403
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• 2002

Urine glucose monitoring system is a self-monitoring system that display the glucose level by non-invasive measurement method. In this paper, We developed a noninvasive urine glucose monitoring system that improved defects of urine glucose measurement with a colorimeter method and invasive blood glucose measurement method. This system consist of bio-chemical sensor for urine glucose measurements, signal detecting part, digital and signal analysis part, display part and power supplying part. The developed bio-chemical sensor for the measurement of urine glucose has good reproducibility, convenience of handing and can be mass-produced with cheap price. To evaluate the performance of the developed system, We performed the evaluation of confidence about the detection of glucose level by a comparison between a standard instrument in measuring glucose level and the developed system using standard glucose solutions mixed with urine. Standard error was 2.85282 from the evaluation of confidence based on regression analysis. Also, In analysis of S.D(standard deviation) and C.V(coefficient of validation) that are important parameters to evaluate system using bio-chemical sensor, S.D was 10% which falls under clinically valid value, 15%, and C.V was under 5%. Consequently from the above results, compared to blood glucose measurement, the system performance is satisfactory.

• Journal of the Korean Institute of Intelligent Systems
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• v.15 no.2
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• pp.230-235
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• 2005

In this paper, we propose an algorithm that improves a tone quality of a noisy audio signal in order to enhance a performance of perceptual filter using intelligent estimation of noise pattern from a band degraded by additive noise. The proposed method doesn't use the estimated noise which is obtained from silent range. Instead new estimated noise according to the power of signal and effect of noise variation is considered for each frame. So the noisy audio signal is enhanced by the method which controls a estimation of noise Pattern effectively in a noise corruption band. To show the performance of the proposed algorithm, various input signals which had a different signal-to-noise ratio(SNR) such as $5\cal{dB},\;10\cal{dB},\;15\cal{dB}\;and\;20\cal{dB}$ were used to test the proposed algorithm. we carry out SSNR and NMR of objective measurement and MOS test of subjective measurement. An approximate improvement of $7.4\cal{dB},\;6.8\cal{dB},\;5.7\cal{dB},\;5.1\cal{dB}$ in SSNR and $15.7\cal{dB},\;15.5\cal{dB},\;15.2\cal{dB},\;14.8\cal{dB}$ in NMR is achieved with the input signals, respectively. And we confirm the enhancement of tone quality in terms of mean opinion score(MOS) test which is result of subjective measurement.

• The Journal of the Korea institute of electronic communication sciences
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• v.17 no.5
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• pp.759-766
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• 2022

In this paper, we propose a multi-band small antenna with CPW(Coplanar Waveguide) feeding structure WLAN(Wireless Local Area Network) and WiMAX (Worldwide Interoperability for Microwave Access) bands. The proposed antenna is designed two slit in the modified monopole type radiator and FR-4 substrate, which is thickness 1.0 mm, and the dielectric constant is 4.4. The size of proposed antenna is 15.1 mm⨯16.41 mm, and total size of proposed antenna is 17.5 mm⨯16.4 mm. From the fabrication and measurement results, From the fabrication and measurement results, bandwidths of 439 MHz (2.06 to 2.499 GHz), 840 MHz (3.31 to 4.25) and 1,315 MHz (5.23 to 6.545 GHz) were obtained on the basis of -10 dB impedance bandwidth. Also, 3D radiation pattern characteristics of the proposed antenna are displayed and measured gains 2.24 dBi, 2.83 dBi, and 2.0 dBi shown in the three frequency band, respectively.

• Journal of Electrical Engineering and Technology
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• v.2 no.3
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• pp.306-311
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• 2007

The transient fields generated during switching operations in a Gas Insulated Substation (GIS) are associated with high frequency components in the order of few tens of MHz. These transient fields leak into the external environment of the gas-insulated equipment and can interfere with the nearby electronics. Measurements of the transient fields are thus required to characterise the interference caused by switching phenomena in such substations. In view of the above, E-field emission measurement during a switching operation has been carried out for a 245 kV GIS model, using a resonant dipole antenna and D-dot sensor. The characteristics of the E-fields i.e., frequency spectra and their levels have been analysed and are reported in the paper. Suitability of the measurements has been confirmed by comparing frequency spectra of the measured and computed transient fields.