• Journal of Sensor Science and Technology
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• v.14 no.5
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• pp.350-356
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• 2005

We have developed a dual-channel type automatic measurement system to evaluate AC-DC current transfer difference of the thermal current converter(TCC) which is primary standard of AC current. The output drift effect of the TCC is minimized by measuring simultaneously the output voltages of two TCCs using voltmeter. Furthermore, the offset voltage of the voltmeter is cancelled nearly out by taking the average values of two outputs of TCCs measured with the forward-reverse directions using dual channel scanner. The uncertainties of the automatic system were 7 to $86{\mu}A/A$ for 3 mA to 10 A at 40 Hz to 20 kHz, which were evaluated by the comparisons between adjacent range of TCCs and inter-comparison with national measurement institute of Germany(PTB). The capability for ac-dc transfer difference measurement was improved by one order compared with that for the manual ac-dc measurement system.

• Structural Engineering and Mechanics
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• v.51 no.2
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• pp.267-276
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• 2014

Wharfs are essential to shipping and support very large gravity loads on both a short-term and long-term basis which cause quite large seismic internal forces. Therefore, these structures are vulnerable to seismic activities. As they are supported on vertical and/or batter piles, soil-pile interaction effects under earthquake events have a great importance in seismic resistance which is not yet fully understood. Seismic design codes have become more stringent and suggest the use of new design methods, such as Performance Based Design principles. According to Turkish Code for Coastal and Port Structures (TCCS 2008), the interaction between soil and pile should somehow be considered in the nonlinear analysis in an accurate manner. This study aims to explore the lateral load carrying capacity of recently designed wharf structures considering soil-pile interaction effects for different soil conditions. For this purpose, nonlinear structure analysis according to TCCS (2008) has been performed comparing simplified and detailed modeling results.

• Coupled systems mechanics
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• v.4 no.3
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• pp.237-249
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• 2015

In the gear meshing process, gear temperature field concerns the meshing surface friction, the friction heat depends on the contact pressure, the contact pressure is affected by the elastic deformation of gears and the temperature field caused by the thermal deformation, so the temperature field, stress field and displacement field should be mutual coupling. It is necessary to consider in meshing gear pair in the operation process of thermodynamic coupling contact stress (TCCS) and thermodynamic coupling deformation (TCD), and based on thermodynamic coupling analysis (TCA) of gear teeth deformation.

• Journal of Yeungnam Medical Science
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• v.37 no.3
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• pp.186-193
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• 2020

Background: Non-tunneled catheters (NTCs) are used for hemodialysis (HD) in many centers in which fluoroscopy is not easily accessed despite high complication rates and conditions requiring long-term HD. Therefore, here we aimed to evaluate the superiority of catheter-related outcomes after the application of tunneled cuffed catheter (TCC) without fluoroscopy versus unconditioned NTC insertion. Methods: We divided the participants into two phases: those receiving NTCs between March 2010 and February 2011 (phase I), and those receiving TCCs or NTCs between March 2011 and February 2012 (phase II). Catheter survival, nurse satisfaction, and reasons for catheter removal were analyzed. Results: Two hundred and sixty patients in phase I and 300 patients in phase II were enrolled in this study. The success rate of TCC insertion was 99.2%. The catheter survival rate in phase I was 65.5% at 1 month, while that in phase II was 74.9% at 1 month (p=0.023). We compared catheter survival between TCCs and NTCs for all periods regardless of phase. The TCC survival rate was higher than the NTC survival rate (p<0.001). Catheter-associated problems led to catheter removal in 97 patients (26.6%) in phase I and 68 patients (18.5%) in phase II (p=0.009). Among 14 HD nurses, all reported being satisfied with manipulation during pre-/post-HD, manupulation during HD, and overall. Eleven HD nurses (78.6%) reported being satisfied with the workload. Conclusion: Compared with unconditional NTC insertion for HD, TCC insertion without fluoroscopy improved the overall catheter survival and nurse satisfaction rates.

• Current Optics and Photonics
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• v.7 no.5
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• pp.537-544
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• 2023

Differential phase contrast (DPC) microscopy, a central quantitative phase imaging (QPI) technique in cell biology, facilitates label-free, real-time monitoring of intrinsic optical phase variations in biological samples. The existing DPC imaging theory, while important for QPI, is grounded in paraxial diffraction theory. However, this theory lacks accuracy when applied to high numerical aperture (NA) systems that are vital for high-resolution cellular studies. To tackle this limitation, we have, for the first time, formulated a nonparaxial DPC imaging equation with a transmission cross-coefficient (TCC) for high NA DPC microscopy. Our theoretical framework incorporates the apodization of the high NA objective lens, nonparaxial light propagation, and the angular distribution of source intensity or detector sensitivity. Thus, our TCC model deviates significantly from traditional paraxial TCCs, influenced by both NA and the angular variation of illumination or detection. Our nonparaxial imaging theory could enhance phase retrieval accuracy in QPI based on high NA DPC imaging.

• Journal of the Korean Society of Propulsion Engineers
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• v.11 no.6
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• pp.26-34
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• 2007

The efforts to develop high performance aircraft engines are successively progressed with development of recent technology. The reliability of individual parts and the safety of engine systems are reduced if high efficiency components, high strength materials, and precise controls are applied to the engine with complexity to increase engine performance. In this paper, the regulation requirements and assessment technique for aircraft engine safety are considered, and the result of safety assessment on a turbine case cooling system of high efficiency turbofan engine is presented.

• 한국전산유체공학회:학술대회논문집
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• 2005.10a
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• pp.269-273
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• 2005

The on-board system for the air supply to the payload fairing(PLF) of a launch vehicle using both high and low pressure air was designed. The design concept was obtained from the CFD analysis of a Russian interstage air supply system, and a collector was adopted to expand the high pressure air. To verify that the on-board system would work as designed, a simplified axisymmetric computational model was made and a CFD analysis was also performed. It was found that the flow ejected from the hole of the collector expands to the Mach number of 4 and is soon retarded due to the action of viscosity. It was also found that a small gap between the low pressure duct and equipment bay wall can cause large velocity in PLF over the velocity requirement and no gap should be allowed in the design.

• Journal of Sensor Science and Technology
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• v.1 no.1
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• pp.77-83
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• 1992

A primary standard of ac current at low frequency is derived from the standard of dc current by ac-dc transfer instrument. A set of 15 thermal current converters(TCCs) have been constructed as the primary current standards from 5 mA to 20 A at the frequency range of 10 Hz to 100 kHz. It is evaluated that the uncertainties for the maintenance and dissemination of ac current standard are less than 52 ppm up to 20 mA and 20 kHz, 60 ppm up to 100 mA and 20 kHz, and rising to 200 ppm at higher currents and frequencies.

• Atmosphere
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• v.22 no.4
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• pp.455-464
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• 2012

This study investigates a 12 month-lead predictability of PNU Coupled General Circulation Model (CGCM) V1.1 hindcast, for which an oceanic data assimilated initialization is used to generate ocean initial condition. The CGCM, a participant model of APEC Climate Center (APCC) long-lead multi-model ensemble system, has been initialized at each and every month and performed 12-month-lead hindcast for each month during 1980 to 2011. The 12-month-lead hindcast consisted of 2-5 ensembles and this study verified the ensemble averaged hindcast. As for the sea-surface temperature concerns, it remained high level of confidence especially over the tropical Pacific and the mid-latitude central Pacific with slight declining of temporal correlation coefficients (TCC) as lead month increased. The CGCM revealed trustworthy ENSO prediction skills in most of hindcasts, in particular. For atmospheric variables, like air temperature, precipitation, and geopotential height at 500hPa, reliable prediction results have been shown during entire lead time in most of domain, particularly over the equatorial region. Though the TCCs of hindcasted precipitation are lower than other variables, a skillful precipitation forecasts is also shown over highly variable regions such as ITCZ. This study also revealed that there are seasonal and regional dependencies on predictability for each variable and lead.

• Korean Journal of Construction Engineering and Management
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• v.10 no.3
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• pp.139-147
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• 2009

Accurate construction cost estimation in the initial stage of building project plays a key role for project success and for mitigation of disputes. Total construction cost(TCC) estimation of apartment projects in Vietnam has become more important because those projects increasingly rise in quantity with the urbanization and population growth. This paper presents the application of artificial neural networks(ANNs) in estimating TCC of apartment projects. Ninety-one questionnaires were collected to identify input variables. Fourteen data sets of completed apartment projects were obtained and processed for training and generalizing the neural network(NN). MATLAB software was used to train the NN. A program was constructed using Visual C++ in order to apply the neural network to realistic projects. The results suggest that this model is reasonable in predicting TCCs for apartment projects and reinforce the reliability of using neural networks to cost models. Although the proposed model is not validated in a rigorous way, the ANN-based model may be useful for both practitioners and researchers. It facilitates systematic predictions in early phases of construction projects. Practitioners are more proactive in estimating construction costs and making consistent decisions in initial phases of apartment projects. Researchers should benefit from exploring insights into its implementation in the real world. The findings are useful not only to researchers and practitioners in the Vietnam Construction Industry(VCI) but also to participants in other developing countries in South East Asia. Since Korea has emerged as the first largest foreign investor in Vietnam, the results of this study may be also useful to participants in Korea.