• Journal of Electrical Engineering and Technology
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• 제9권1호
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• pp.27-36
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• 2014

This paper presents an adaptive wide-area damping controller (WADC) based on generalized predictive control (GPC) and model identification for damping the inter-area low frequency oscillations in large-scale inter-connected power system. A recursive least-squares algorithm (RLSA) with a varying forgetting factor is applied to identify online the reduced-order linearlized model which contains dominant inter-area low frequency oscillations. Based on this linearlized model, the generalized predictive control scheme considering control output constraints is employed to obtain the optimal control signal in each sampling interval. Case studies are undertaken on a two-area four-machine power system and the New England 10-machine 39-bus power system, respectively. Simulation results show that the proposed adaptive WADC not only can damp the inter-area oscillations effectively under a wide range of operation conditions and different disturbances, but also has better robustness against to the time delay existing in the remote signals. The comparison studies with the conventional lead-lag WADC are also provided.

• JSTS:Journal of Semiconductor Technology and Science
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• 제14권5호
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• pp.572-578
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• 2014

In order to overcome small current drivability of a tunneling field-effect transistor (TFET), a TFET using Schottky barrier (SBTFET) is proposed. The proposed device has a metal source region unlike the conventional TFET. In addition, dopant segregation technology between the source and channel region is applied to reduce tunneling resistance. For TFET fabrication, spacer technique is adopted to enable self-aligned process because the SBTFET consists of source and drain with different types. Also the control device which has a doped source region is made to compare the electrical characteristics with those of the SBTFET. From the measured results, the SBTFET shows better on/off switching property than the control device. The observed drive current is larger than those of the previously reported TFET. Also, short-channel effects (SCEs) are investigated through the comparison of electrical characteristics between the long- and short-channel SBTFET.

• Investigative Magnetic Resonance Imaging
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• 제24권2호
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• pp.76-84
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• 2020

Background: Determination of inter-method differences between clinically available volumetry methods are essential for the clinical application of brain volumetry in a wider context. Purpose: The purpose of this study was to examine the inter-method reliability and differences between the Siemens morphometry (SM) software and the NeuroQuant (NQ) software. Materials and Methods: MR images of 86 subjects with subjective or objective cognitive impairment were included in this retrospective study. For this study, 3D T1 volume images were obtained in all subjects using a 3T MR scanner (Skyra 3T, Siemens). Volumetric analysis of the 3D T1 volume images was performed using SM and NQ. To analyze the inter-method difference, correlation, and reliability, we used the paired t-test, Bland-Altman plot, Pearson's correlation coefficient, intraclass correlation coefficient (ICC), and effect size (ES) using the MedCalc and SPSS software. Results: SM and NQ showed excellent reliability for cortical gray matter, cerebral white matter, and cerebrospinal fluid; and good reliability for intracranial volume, whole brain volume, both thalami, and both hippocampi. In contrast, poor reliability was observed for both basal ganglia including the caudate nucleus, putamen, and pallidum. Paired comparison revealed that while the mean volume of the right hippocampus was not different between the two software, the mean difference in the left hippocampus volume between the two methods was 0.17 ml (P < 0.001). The other brain regions showed significant differences in terms of measured volumes between the two software. Conclusion: SM and NQ provided good-to-excellent reliability in evaluating most brain structures, except for the basal ganglia in patients with cognitive impairment. Researchers and clinicians should be aware of the potential differences in the measured volumes when using these two different software interchangeably.

• 한국대기환경학회지
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• 제34권1호
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• pp.87-100
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• 2018

Fast economic growth and urbanization of China have been causing air pollution not only over its domestic but transboundary atmosphere. Recent high fine particle pollution episodes in China made the government move toward more stringent air pollution control policies - which are mostly fuel switching and emissions control. In this research, we tried to understand characteristics of Chinese emissions and their change by analyzing its emissions inventory by year, sector, and region. From the inter-comparison of existing bottom-up emission inventories, we found relatively good agreements (<20% difference) for $SO_2$ and $NO_x$, but 30% or more discrepancies for some pollutants. Inter-comparison with top-down $NO_x$ emissions estimates also showed 20~50% differences by year. The regional distribution and inter-annual changes of emissions revealed different stages of energy/fuel mix and policy penetration. Early increase of pollutants emissions in the eastern part of China might give strong influences to the Korean peninsular in early 2000s but, more stringent control in that region would help improving air pollution in Korea in near future.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2023년도 학술발표회
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• pp.161-161
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• 2023

Bias correction of values is a necessary step in downscaling coarse and systematically biased global climate models for use in local climate change impact studies. In addition to univariate bias correction methods, many multivariate methods which correct multiple variables jointly - each with their own mathematical designs - have been developed recently. While some literature have focused on the inter-comparison of these multivariate bias correction methods, none have focused extensively on the effect of diverse configurations (i.e., different combinations of input variables to be corrected) of climate variables, particularly high-dimensional ones, on the ability of the different methods to remove biases in uni- and multivariate statistics. This study evaluates the impact of three configurations (inter-variable, inter-spatial, and full dimensional dependence configurations) on four state-of-the-art multivariate bias correction methods in a national-scale domain over South Korea using a gridded approach. An inter-comparison framework evaluating the performance of the different combinations of configurations and bias correction methods in adjusting various climate variable statistics was created. Precipitation, maximum, and minimum temperatures were corrected across 306 high-resolution (0.2°) grid cells and were evaluated. Results show improvements in most methods in correcting various statistics when implementing high-dimensional configurations. However, some instabilities were observed, likely tied to the mathematical designs of the methods, informing that some multivariate bias correction methods are incompatible with high-dimensional configurations highlighting the potential for further improvements in the field, as well as the importance of proper selection of the correction method specific to the needs of the user.

• 산업공학
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• 제12권4호
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• pp.532-539
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• 1999

The first step to design a cellular manufacturing system is to make part-families and machine-cells. This process is called the machine-part grouping. This paper considers a machine-cell size when grouping machine-cells. By considering a machine-cell size, an unrealistically big size of machine-cell which may be caused by the chaining effect can be avoid. A heuristic algorithm which minimizes the number of inter-cell movement of parts considering a machine-cell size is presented. The effectiveness and performance of the proposed heuristic algorithm are compared with those of several heuristic algorithms previously reported. The comparison shows that the proposed heuristic algorithm is efficient and reliable in minimizing the number of inter-cell movement of parts and also prevents the chaining effect.

• 한국영어학회지:영어학
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• 제4권1호
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• pp.83-102
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• 2004

The purpose of this paper is to find out some major characteristics of intermediate-advanced Korean learners' English by corpus- linguistically analyzing their essays in comparison with native speakers'. We construct a corpus of CBT TOEFL essays by Korean learners, NNS1 (94076 words in 402 texts), and its sub-corpus, NNS2 (14291 words in 45 texts), and then a corpus of model essays written or meticulously edited by native speakers, NS (14833 words in 35 texts). We compare NNS1 and NNS2 with NS, and with some other corpora, in terms of high-frequency words, and show that Korean learners' writings have more features of informal writing than those of formal writing, which is in accord with the reports in Granger (1998) that EFL writings by European advanced learners are characterized by informality.

• Journal of Information Display
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• 제2권3호
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• pp.66-71
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• 2001

MCFEDs (MOSFET-Contoolled Field Emission Displays) were fabricated to evaluate the validity of MCFEA for display application. The electrical properties of FEAs (Field Emitter Arrays), HVMOSFETs (High-Voltage MOSFETs), and MCFEAs (MOSFET-Controlled Field Emitter Arrays) were measured. The extraction gate voltage of the FEAs to obtain the anode current of 10 nA/tip was around 71 V. The breakdown voltages of the HVMOSFETs were above 81 V for all the samples. The I-V characteristics of the MCFEAs showed that the emission currents of the FEAs were well controlled depending on the control gate voltages of the HVMOSFETs. To avoid the harmful effects during the packaging process, the performance of the MCFEDs was evaluated in a high vacuum chamber. The emission images of the MCFEDs were controlled through very-through operation. From the comparison with a conventional FED, it was proven that the poor uniformity of FED could be improved through the integration with HVMOSFET.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권2호
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• pp.1201-1216
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• 2017

In this study, we described the development of a methodology to measure tip-pinch strength on the paretic hand rehabilitation device and aimed to investigate reliability of the device. FSR sensors were embedded on the device, and tip pinch strength was estimated with data collected from the sensors using a developed equation while participants were demonstrating tip pinch. Reliability tests included inter-rater, test-retest, and inter-instrument reliability. B&L Engineering pinch gauge was utilized for the comparison. Thirty-seven healthy students participated in the experiment. Both inter-rater and test-retest reliability were excellent as Intraclass Correlation Coefficients (ICCs) were greater than 0.9 (p<0.01). There were no statistically significant differences in tip-pinch strengths. Inter-instrument reliability analysis confirmed good correlation between the two instruments (r = 0.88, p < 0.01). The findings of this study suggest that the two instruments are not interchangeable. However, the tip-pinch mechanism used in the paretic hand rehabilitation device is reliable that can be used to evaluate tip pinch strength in clinical environment and can provides a parameter that monitors changes in the hand functions.

• Clinical and Experimental Reproductive Medicine
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• 제29권4호
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• pp.323-335
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• 2002

Object: The present study was accomplished to obtain a gene expression profile of the luminal epithelium during embryo apposition in comparison of implantation (1M) and interimplantation (INTER) sites. Material and Method: The mouse uterine luminal epithelium from IM and INTER sites were sampled on day 4.5 (Day of vaginal plug = day 0.5) by Laser Captured Microdissection (LCM). RNA was extracted from LCM captured epithelium, amplified, labeled and hybridized to microarrays. Results from microarray hybridization were analyzed by Significance Analysis of Microarrays (SAM) method. Differential expression of some genes was confirmed by LCM followed by RT-PCR. Results: Comparison of IM and INTER sites by SAM identified 73 genes most highly ranked at IM, while 13 genes at the INTER sites, within the estimated false discovery rate (FDR) of 0.163. Among 73 genes at IM, 20 were EST/unknown function, and the remain 53 were categorized to the structural, cell cycle, gene/protein expression, immune reaction, invasion, metabolism, oxidative stress, and signal transduction. Of the 24 structural genes, 14 were related especially to extracellular matrix and tissue remodeling. Meanwhile, among 13 genes up-regulated at INTER, 8 genes were EST/unknown function, and the rest 5 were related to metabolism, signal transduction, and gene/protein expression. Among these 58 (53+5) genes with known functions, 13 genes (22.4%) were related with $Ca^{2+}$ for their function. Conclusions: Results of the present study suggest that 1) active tissue remodeling is occurring at the IM sites during embryo apposition, 2) the INTER sites are relatively quiescent than IM sites, and 3) the $Ca^{2+}$ may be a crucial for apposition. Search for human homologue of those genes expressed in the mouse luminal epithelium during apposition will help to understand the implantation process and/or implantation failure in humans.