• 대한기계학회논문집B
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• 제26권2호
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• pp.362-373
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• 2002

A stereoscopic PIV (SPIV) measurement system based on the translation configuration was developed and applied to the flow behind a forward-swept axial-fan. Measurement of three orthogonal velocity components is essential for flow analysis of three-dimensional flows such as flow around a fan or propeller. In this study, the translation configuration was adopted to calculate the out-of-plane velocity component from 2-D PIV data obtained from two CCD cameras. The error caused by the out-of-plane motion was estimated by direct comparison of the 2-D PIV and 3-D SPIV results that measured from the particle images captured simultaneously. The comparison shows that the error ratio is relatively high in the region of higher out-of-plane motion near the axial fan blade. The turbulence intensity measured by the 2-D PIV method is bigger by about 5.8% in maximum compared with that of the 3-D SPIV method. The phase-averaged velocity field results show that the wake behind an axial fan has a periodic flow structure with respect to the blade phase and the characteristic flow structure is shifted downstream in the next phase.

• 복식문화연구
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• 제19권6호
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• pp.1359-1371
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• 2011

The purpose of this paper is to compare two avatars made using direct and manual methods and to evaluate the fit and appearance of two virtual garments on the direct and manual avatars. In this study, two subjects were measured by $[TC]^2$ body scanner and the avatars and virtual garments were created by OptiTex software. The direct avatar was made by the direct importation of 3D body scan data and the manual avatar was made by manual input from extracted body measurement. Two virtual garments in a tank-top were evaluated by distance, transparency, and stretch maps. In the results of comparing difference of the direct and manual avatars, the bust and back of the manual avatar are protruded slightly more than that of the direct avatar and the manual avatar is slightly larger dimensions at the bust, waist, abdomen, and hip area in the side view in case of subject 1 and 2. In the results of comparing difference of the fit and appearance of two virtual garments on the direct and manual avatars, in case of subject 1 and 2, the back of the virtual garment on the manual avatar are protruded more than that of the direct avatar. Also, the ease in the bust area of the virtual garment on the manual avatar with a projected bust area was smaller than that of the virtual garment on the direct avatar and the stretch of that of the manual avatar was also high in the bust area. The results of this study are expected to be used as basic information in the apparel industry using virtual try-on technology.

• 대한임상검사과학회지
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• 제44권3호
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• pp.103-111
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• 2012

Low-Density Lipoprotein cholesterol (LDLC) is the most important marker for the treatment of hyperlipidemia in NCEP-ATP III(National Cholesterol Education Program-Adult Treatment Panel III) guideline. Therefore, LDL cholesterol is pathologically meaningful, accurate measurement should be a top priority. Currently, LDLC is directly measured in most cases, but, the estimate is still used in mass health examination or screening test. This study is about the comparison of LDL-Cholesterol direct measurement with the estimate using various formula (Friedewald: [LDL-F=TC-HDL-TG/5], Nakajima: [LDL-N=TC-HDL-TG/4], Hattori: [LDL-H =0.94TC-0.94HDL-0.19TG], Puavilai: [LDL-P=TC-HDL-TG/6], Carvalho: [LDL-C=3(TC-HDL)/4]) for calculating more accurate value. We analyzed total cholesterol (TC), try-glyceride (TG), high-density lipoprotein cholesterol (HDLC), and LDLC levels of 210 subjects between June and November in 2011. Until now, the Friedewald formula is the most commonly used estimate for the LDLC. When Friedewald formula was applied, the correlation coefficient (r) was 0.940, showing high correlation. But, the result of the direct method was significantly different, compared with those of the Friedewald formula in triglyceride levels ${\geq}400mg/dL$(p<0.05). There was the highest correlation when we used LDL-P formula(r=0.947) in triglyceride levels <400 mg/dl. Also there was the lowest mean difference regardless of triglyceride level. Therefore, the study showed that TG/6 is more precise means of calculation than TG/5. On the other hand, the calculation of LDL-Cholesterol was underestimated, compared with direct measurement. It is necessary to have more data and modified Friedewald formula should be used for the accurate calculation.

• 한국자동차공학회논문집
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• 제7권7호
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• pp.66-75
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• 1999

Many researchers have developed the measurement technique of in-cylinder flow. Recently, there are lots of studies on steady flow with different SCV geometries. In this study the flow characteristics of four-valve cylinder head were examined in a steady test rig for different SCV open ratios. Each swirl ratio of several SCV angle was quantified by swirl impulse meter and 2D-LDV measurement. The results showed that the swirl ratio was controlled between 2.3 and 3.8 based on SCV angles. The velocity distributions of in-cylinder flow field were measured by 2-D LDV test and visualized swirl and tumble flow pattern at different positions. In this engine , we found out that the swirl was dominant flow.

• ETRI Journal
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• 제37권5호
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• pp.877-887
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• 2015

This paper is a first-hand summary on our comprehensive live trial of cellular-assisted device-to-device (D2D) communications currently being ratified by the standards community for next-generation mobile broadband networks. In our test implementation, we employ a full-featured 3GPP LTE network deployment and augment it with all necessary support to provide realtime D2D connectivity over emerging Wi-Fi-Direct (WFD) technology. As a result, our LTE-assisted WFD D2D system enjoys the required flexibility while meeting the existing standards in every feasible detail. Further, this paper provides an account on the extensive measurement campaign conducted with our implementation. The resulting real-world measurements from this campaign quantify the numerical effects of D2D functionality on the resultant system performance. Consequently, they shed light on the general applicability of LTE-assisted WFD solutions and associated operational ranges.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 춘계학술대회 논문집
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• pp.396-399
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• 1995

In this study, Acquisition system is proposed to acquire 3 dimensional data of the free surface model using direct pulse control to machining center. Todo this, I/F to connect between manual operating handle and computer is made, and 3 dimensional shape measuring algorithm using Z-map is applied. The 3 dimensional shape data of the free surface model measured by laser displacement sensor and electric touch probe are achieved directly. Performance of the proposed system is evaluated through measurement of various shape model.

• 센서학회지
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• 제5권4호
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• pp.9-15
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• 1996

자기저항 센서로부터 얻은 자기 신호를 표시하기 위하여 직류 자력계를 설계하고, 그 회로를 구현하였다. 제작한 자력계 및 상용 MAG-01 자력계로 측정한 자장은 서로 잘 일치하였고, 제작한 자력계의 자동 범위선택기능, 애널로그 출력기능 및 벡터 감지기능이 양호하였다. 자력계의 측정범위는 $1\;{\mu}T{\sim}1.999\;mT$였고, 분해능은 1 Hz의 밴드폭에서 -132 dB였으며, 측정한 자장은 $3{\cdot}1/2$-digit LED로 표시되었다.

• 대한두개안면성형외과학회지
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• 제14권1호
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• pp.11-15
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• 2013

Background: In cleft lip patients, the necessity of a thorough preoperative analysis of facial deformities before reconstruction is unquestioned. The surgical plan of cleft lip patient is based on the information gained from our preoperative anthropometric evaluation. A variety of commercially available three-dimensional (3D) surface imaging systems are currently introduced to us in plastic surgery for these use. However, few studies have been published on the soft tissue morphology of unrepaired cleft infants described by these 3D surface imaging systems. Methods: The purpose of this study is to determine the accuracy of facial anthropometric measurements obtained through digital 3D photogrammetry and to compare with direct anthropometry for measurement in unilateral cleft lip patients. We compared our patients with three measurements of dimension made on both sides: heminasal width, labial height, and transverse lip length. Results: The preoperative measurements were not significantly different in both side of labial height and left side of heminasal width. Statistically significant differences were found on both side of transverse lip length and right side of heminasal width. Although the half of preoperative measurements were significantly different, trends of results showed average results were comparable. Conclusion: This is the first study in Korea to simultaneously compare digital 3D photogrammetry with traditional direct anthropometry in unilateral cleft lip patients. We desire this study could contribute the methodological choice of the many researchers for proper surgical planning in cleft lip reconstruction field.

• 한국전자파학회논문지
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• 제16권7호
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• pp.681-689
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• 2005

본 논문에서는 IEEE 802.15.3a의 초광대역(Ultra Wideband: UWB) 시스템용 직접 변환 혼합기를 설계 및 제작하였다. 직접 변환 방식을 사용하는 UWB 혼합기는 dc offset, 2차 고조파 왜곡 등을 발생시키는데, 이 문제를 해결하기 위해 역병렬 다이오드 쌍을 이용하였다. 본 논문에서는 $3.1\~4.8$ GHz 동위상 전력분배기와 $1.5\~2.4$ GHz 광대역 $45^{\circ}$ 위상 분배기 설계를 위하여 결합선로를 이용한 새로운 월킨슨 분배기를 제안하였다. 역병렬 다이오드 구조와 광대역 소자를 이용한 혼합기의 제작 결과는 주파수 변환 손실이 약 18 dB, input third order intercept point($IIP_3$)는 약 15 dBm, 그리고 1-dB gain compression point($P_{1dB}$)는 2 dBm으로 측정되었다. I/Q 출력 양단 간의 전력오차는 0.5 dB, 그리고 위상오차는 ${\times}3^{\circ}$를 지닌 초광대역 쿼드러쳐 혼합기로 동작하였다.

• 설비공학논문집
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• 제2권3호
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• pp.243-255
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• 1990

The objective of this study is to present an efficient measurement method of the effective thermal diffusivity for the fibrous insulation material. The non-linear parameter estimation (NPE) method is adapted for this analysis because of its accuracy and its results are compared with those by other direct methods such as CTP, CHP and STD method. A experimental system is constructed with bell-jar vaccum chamber, diffusion pump, tube type furnace, control unit and data acquisition system included with A/D converter and IBM XT/AT personal computer. The typical results obtained from this study are as follows; 1) NPE method can be recommended as an useful and accurate method to measure the effective thermal diffusivity of insuation material because it is shown that the measurement error compared with those by other direct methods is reduced for standard material, NBS-1450b. 2) NPE method can minimize the effects of ill-measured temperature due to external disturbance, because the final value is found by point to point estimating. 3) NPE method dose not depend on the kinds of heat flux, since the surfac temperature are used to estimate the thermal diffusivity. 4) With NPE method, compared with the steady state method, a measuring time and a sample size could be reduced.