• Restorative Dentistry and Endodontics
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• 제45권4호
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• pp.48.1-48.11
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• 2020

Objectives: This systematic review aimed to identify mean oxygen saturation values (SpO₂) using pulse oximetry in permanent maxillary anterior teeth. Materials and Methods: The MEDLINE, Scientific Electronic Library Online, Cochrane Central Register of Controlled Trials, EMBASE, and Literatura Latino Americana em Ciências da Saúde electronic databases were searched. Combinations and variations of "oximetry" AND "dental pulp test" were used as search terms. Studies reporting means and standard deviations of SpO₂ values were included. Two reviewers independently extracted data following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses checklist. Heterogeneity was assessed using the I² statistic, and all analyses were performed using R software. Study quality was assessed using the Quality Assessment of Diagnostic Accuracy Studies-2 tool and the Newcastle-Ottawa scale. Results: Of the 251 studies identified, 19 met the eligibility criteria and were included (total sample, 4,541 teeth). In the meta-analysis, the mean SpO₂ values were 84.94% (95% confidence interval [CI], 84.85%-85.04%) for the central incisors, 89.29% (95% CI, 89.22%-89.35%) for the lateral incisors, and 89.20% (95% CI, 89.05%-89.34%) for the canines. The studies were predominantly low-quality due to the high risk of bias associated with the index test, unclear risk regarding patient selection, and concerns about outcome assessment. Conclusions: Although most studies were low-quality, the oxygen saturation levels in normal pulp could be established (minimum saturation, 77.52%). Despite the risk of bias of the included studies, the reference values reported herein are clinically relevant for assessments of changes in pulp status.

• 전기전자학회논문지
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• 제20권2호
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• pp.192-195
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• 2016

본 논문에서는 저항과 BJT를 사용하지 않고 sub-threshold 영역에서 동작하는 저전압, 저전력 기준전압 발생기를 설계하였다. CTAT 전압 발생기는 두 개의 NMOS 트랜지스터를 이용하여 구성하였고, 충분한 영역의 CTAT 전압을 발생시키기 위해 바디 바이어스 회로를 이용하였다. PTAT 전압 발생기는 PTAT 전압을 생성하기 위해 MOS 트랜지스터 입력 쌍의 서로 다른 사이즈 비를 이용하는 차동증폭기 형태로 구성하였다. 제안한 회로는 $0.18-{\mu}m$ 표준 CMOS 공정으로 설계되었다. 시뮬레이션 결과로 290mV의 출력 기준 전압을 가지며, -$20^{\circ}C$ 에서 $120^{\circ}C$의 온도 변화에서 92 ppm/$^{\circ}C$의 전압 변화 지수와 전원전압 0.63V에서 15.7nW의 소모 전력을 갖는 것을 확인하였다.

• Korean Journal of Radiology
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• 제24권2호
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• pp.155-165
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• 2023

Objective: Little is known about the effects of using different expert-determined reference standards when evaluating the performance of deep learning-based automatic detection (DLAD) models and their added value to radiologists. We assessed the concordance of expert-determined standards with a clinical gold standard (herein, pathological confirmation) and the effects of different expert-determined reference standards on the estimates of radiologists' diagnostic performance to detect malignant pulmonary nodules on chest radiographs with and without the assistance of a DLAD model. Materials and Methods: This study included chest radiographs from 50 patients with pathologically proven lung cancer and 50 controls. Five expert-determined standards were constructed using the interpretations of 10 experts: individual judgment by the most experienced expert, majority vote, consensus judgments of two and three experts, and a latent class analysis (LCA) model. In separate reader tests, additional 10 radiologists independently interpreted the radiographs and then assisted with the DLAD model. Their diagnostic performance was estimated using the clinical gold standard and various expert-determined standards as the reference standard, and the results were compared using the t test with Bonferroni correction. Results: The LCA model (sensitivity, 72.6%; specificity, 100%) was most similar to the clinical gold standard. When expert-determined standards were used, the sensitivities of radiologists and DLAD model alone were overestimated, and their specificities were underestimated (all p-values < 0.05). DLAD assistance diminished the overestimation of sensitivity but exaggerated the underestimation of specificity (all p-values < 0.001). The DLAD model improved sensitivity and specificity to a greater extent when using the clinical gold standard than when using the expert-determined standards (all p-values < 0.001), except for sensitivity with the LCA model (p = 0.094). Conclusion: The LCA model was most similar to the clinical gold standard for malignant pulmonary nodule detection on chest radiographs. Expert-determined standards caused bias in measuring the diagnostic performance of the artificial intelligence model.

• 한국정밀공학회지
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• 제31권7호
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• pp.605-613
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• 2014

Scanning white-light interferometry is an important measurement option for many surfaces. However, serious profile measurement errors can be present when measuring free-form surfaces being highly curved or tilted. When the object surface slope is not zero, the object and reference rays are no longer common path and optical aberrations impact the measurement. Aberrations mainly occur at the beam splitter in the interference objective and from misalignment in the optical system. Both effects distort the white-light interference signal when the surface slope is not zero. In this paper, we describe a modified version of white-light interferometry for eliminating these measurement errors and improving the accuracy of white-light interferometry. Moreover, we report systematic errors that are caused by optical aberrations when the object is not flat, and compare our proposed method with the conventional processing algorithm using the random ball test.

• Transactions on Electrical and Electronic Materials
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• 제15권6호
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• pp.309-314
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• 2014

This work proposes an integrated high frequency divider with an inductive peaking technique implemented in a current mode logic (CML) frequency divider. The proposed divider is composed with a master-slave flip-flop, and the master-slave flip-flop acts as a latch and read circuits which have the differential pair and cross-coupled n-MOSFETs. The cascode bias is applied in an inductive peaking circuit as a current source and the cascode bias is used for its high current driving capability and stable frequency response. The proposed divider is designed with $0.18-{\mu}m$ CMOS process, and the simulation used to evaluate the divider is performed with phase-locked loop (PLL) circuit as a feedback circuit. A divide-by-two operation is properly performed at a high frequency of 20 GHz. In the output frequency spectrum of the PLL, a peak frequency of 2 GHz is obtained witha divide-by-eight circuit at an input frequency of 250 MHz. The reference spur is obtained at -64 dBc and the power consumption is 13 mW.

• 한국도서관정보학회지
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• 제36권1호
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• pp.173-193
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• 2005

현대사회는 지식$\cdot$정보사회이며, 도서관은 지식과 정보가 전달되는 중요한 경로 중의 하나이다. 그렇지만 여러 가지 요인에 의해 도서관의 장서는 그 생산과 수집, 그리고 축적의 과정에서부터 편견과 왜곡으로 인한 굴절과 편향을 멀 수밖에 없었으며. 그것은 결과적으로 도서관이 현대사회의 지식$\cdot$정보의 유통기관으로서의 본질을 흐리게 만드는 주된 요인이 되어왔다. 이 연구는 장서연구의 필요성과 주요 해결 과제, 그리고 그 방법론에 대한 고찰이다. 장서 연구는 도서관장서의 축적 과정에 초점을 맞추어 그 장서가 편향성을 띠어 가는 과정을 추적하고 그 편향성의 현단계를 밝히는 작업이 그 출발점이 되어야 할 것이다.

• 성인간호학회지
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• 제29권2호
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• pp.177-189
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• 2017

Purpose: A meta-analysis was conducted to identify the effect of cognitive improvement programs for the elderly with mild cognitive impairment (MCI) in Korea. Methods: Five databases, as well as relevant reference lists, of studies published from 2000 to 2016, were searched. Fourteen studies were identified. Quality assessments of included studies were conducted using the Scottish Intercollegiate Guidelines Network checklist. An R program was used to analyze effect sizes and to identify possible sources of heterogeneity among studies. The potential for publication bias was investigated using a funnel plot, Egger's regression test and sensitivity analysis. Results: The total effect size was large (Standardized Mean Difference [SMD]=1.44, 95% CI: 1.11~1.77), with cognition based intervention (SMD= 1.77, 95% CI: 1.26~2.29) and exercise intervention (SMD=1.13, 95% CI: 0.82~1.44). Statistically significant moderators were identified intervention type by meta-ANOVA analyses. Finally, no significant evidence of publication bias was found. Conclusion: There is clear evidence that cognitive improvement programs can greatly enhance cognition in elderly with MCI. Future research should examine the effects of non-pharmacological interventions targeting elderly populations with mild-to-severe cognitive impairment in order to develop and enhance the effectiveness of cognitive improvement programs in Korea.

• JSTS:Journal of Semiconductor Technology and Science
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• 제3권2호
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• pp.83-88
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• 2003

The reset operation of a CCD image sensor was improved using charge trapping of a MOS structure to realize a loe voltage driving. A DC bias generating circuit was added to the reset structure which sets reference voltage and holds the signal charge to be detected. The generated DC bias is added to the reset pulse to give an optimized voltage margin to the reset operation, and is controlled by adjustment of the threshold voltage of a MOS transistor in the circuit. By the pulse-type stress voltage applied to the gate, the electrons and holes were injected to the gate dielectrics, and the threshold voltage could be adjusted ranging from 0.2V to 5.5V, which is suitable for controlling the incomplete reset operation due to the process variation. The charges trapped in the silicon nitride lead to the positive and negative shift of the threshold voltage, and this phenomenon is explained by Poole-Frenkel conduction and Fowler-Nordheim conduction. A CCD image sensor with $492(H){\;}{\times}{\;}510(V)$ pixels adopting this structure showed complete reset operation with the driving voltage of 3.0V. The resolution chart taken with the image sensor shows no image flow to the illumination of 30 lux, even in the driving voltage of 3.0V.

• Nuclear Engineering and Technology
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• 제51권7호
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• pp.1853-1859
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• 2019

The two-thermocouple method was investigated experimentally to evaluate its accuracy for the measurement of local wall temperature and heat flux on a heat transfer tube with an electric heater rod installed in an annulus channel. This work revealed that a thermocouple flush-mounted in a surface groove serves as a good reference method for the accurate measurement of the wall temperature, whereas two thermocouples installed at different depths in the tube wall yield large bias errors in the calculation of local heat flux and wall temperature. These errors result from conductive and convective changes due to the fin effect of the thermocouple sheath. To eliminate the bias errors, we proposed a calibration method based on both the local heat flux and Reynolds number of the cooling water. The calibration method was validated with the measurement of local heat flux and wall temperature against experimental data obtained for single-phase convection and two-phase condensation flows inside the tube. In the manuscript, Section 1 introduces the importance of local heat flux and wall temperature measurement, Section 2 explains the experimental setup, and Section 3 provides the measured data, causes of measurement errors, and the developed calibration method.

• 한국항공우주학회지
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• 제50권9호
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• pp.617-625
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• 2022

본 논문은 사격 차선 정렬을 위하여 움직일 수 있는 교정 대상을 이용해 각속도계와 가속도계의 편차를 보상하는 방법을 다룬다. 교정 대상에 대한 정보는 영상 센서를 통해 획득하며 이를 이용해 발사장치에 부착된 관성측정 장치의 오차를 보정한다. 시뮬레이션을 통해 제안한 알고리즘의 성능을 검증하였으며, 특히 관성 좌표계에서 교정 대상에 대한 위치 정보를 정확하게 획득함으로써 발사장치의 관성 센서 편차를 효과적으로 보상할 수 있음을 보인다.