• Bulletin of the Korean Chemical Society
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• v.25 no.7
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• pp.1085-1087
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• 2004

• The Mathematical Education
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• v.31 no.2
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• pp.93-107
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• 1992

The purpose of this study is to make out teaching-learning method for developing mathematical abilities of the 1st grade children in elementary school by investigating cognitive effects which mathematical pre-experiences given intentionally by teachers have on children's learning mathematics. The research questions for this purpose are as follows: In learning effects through mathematical pre-experiences given intentionally by teachers. 1) is there any differences between children with pre-experiences and children without them in Mathematics Achievement Test\ulcorner 2) is there any differences between children with pre-experiences and children without them in Transfer Test for learning effects\ulcorner For this study, a class with 41 children in H elementary school located in a Myon near Chong-ju was selected as an experimental group and a class with 43 children in G elementary school in the same Myon was selected as a control group. Nonequivalent Control Group Design of Quasi-Experimental Design was applied to this study. To give pre-experiences to the children in experimental group, their classroom was equipped with materials for pre-experiences, so children could always observe the materials and play with them. The materials were a round-clock on the wall, two pairs of scales, fifty dice, some small pebbles, two pairs of weight scales, two rulers on the wall, and various cards for playing games. Pre-experiences were given to the children repeatedly through games and observations during free time in the morning (00:20-09:00) and intervals between periods. There was a pretest for homogeneity of mathematics achievement between the two groups and were Mathematics Achievement Test (30 items) and Transfer Test (25 items) for learning effects as post-tests. The data were collected from the pretest on April 8 (control group), on April 11 (experimental group) and from the Mathematics Achievement Test and Transfer Test on July 15 (experimental group) and on July 16 (control group). T-test was used to analyze if there were any differences in the results of the test. The results of the analysis were as follows: (1) As the result of pretest, there was not a significance difference between the experimental group (M=17.10. SD=7.465) and the control group (M=16.31, SD=6.974) at p<.05 (p=0.632). (2) For the question 1. in the Mathematics Achievement Test, there was a significant difference between the experimental group (M=26.08, SD=4.827) and the control group (M=22.28. SD=5.913) at p<.01 (p=.003). (3) For the question 2. in the Transfer Test for learning effects. there was a significant difference between the experimental group (M=16.41, SD=5.800) and the control group (M=11.84, SD=4.815) at p<001, (p=.000). From the results of the analyses obtained in this study. the following conclusions can be drawn: First, mathematical pre-experiences given by teachers are effective in increasing mathematical achievement and transfer in learning mathematics. Second, games. observations, and experiments given intentionally by teachers can make children's mathematical experiences rich and various, and are effective in adjusting individual differences for the mathematical experiences obtained before they entered elementary schools. Third, it is necessary for teachers to give mathematical pre-experiences with close attention in order to stimulate children's mathematical interests and intellectual curiosity.

• Phonetics and Speech Sciences
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• v.9 no.4
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• pp.35-41
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• 2017

The existence and the extent of vowel length difference before voiced/voiceless consonants in English and Korean are examined in three groups: (1) Korean-speaking Americans (group A), (2) immigrants who moved to the U.S. in their early teens (group I), and (3) Koreans who have been in the U.S. for less than 3 years (group K). 14 subjects were recorded reading 10 English and 10 Korean sentences. The results show that the three groups exhibit different patterns of the vowel length difference: Group A shows a very strong tendency of vowel lengthening before voiced consonants in both English and Korean, while Group I shows less degree of vowel lengthening, and Group K shows almost no tendency of vowel length difference in both languages. This strongly suggests that, (1) unlike English, Korean does not have the vowel length difference depending on the following consonants, and (2) the vowel lengthening effect observed in Korean (L2) speech in group A may be the result of transfer of the phonetic trait acquired in English (L1). It also implies that, in teaching pronunciation, some facts such as the vowel length difference cannot be expected to be acquired automatically for the learners of English, but have to be taught explicitly.

• Clinical and Experimental Reproductive Medicine
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• v.51 no.1
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• pp.63-68
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• 2024

Objective: This study was conducted to investigate the impact of previous delivery mode on pregnancy outcomes in patients with secondary infertility after frozen-thawed embryo transfer. Methods: This prospective observational study included 140 patients experiencing secondary infertility. Of these, 70 patients had a previous cesarean delivery (CD), while the remaining 70 patients had a previous normal vaginal delivery (NVD). The primary outcome was the implantation rate. The secondary outcomes included rates of clinical pregnancy, chemical pregnancy, miscarriage, and ectopic pregnancy. Results: The comparison of all fertility outcomes between the two groups revealed no statistically significant differences. The implantation rate was 40.4% in the CD group and 41.7% in the NVD group (p=0.842). The clinical pregnancy rate was 50% in the CD group and 49.3% in the NVD group (p=0.932), while the chemical pregnancy rate was 14.6% in the CD group and 19% in the NVD group (p=0.591). The miscarriage rates in the CD and NVD groups were 20% and 17.6%, respectively (p=0.803). One case of tubal ectopic pregnancy occurred in the NVD group (1.4%). Conclusion: The mode of prior delivery did not significantly impact pregnancy outcomes following frozen-thawed embryo transfer.

• Journal of Power Electronics
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• v.16 no.5
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• pp.1678-1688
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• 2016

This paper presents a capacitive power transfer (CPT) system using a Class-E resonant inverter. A Class-E resonant inverter is chosen because of its ability to perform DC-to-AC inversion efficiently while significantly reducing switching losses. The proposed CPT system consists of an efficient Class-E resonant inverter and capacitive coupling formed by two flat rectangular transmitter and receiver plates. To understand CPT behavior, we study the effects of various coupling distances on output power performance. The proposed design is verified through lab experiments with a nominal operating frequency of 1 MHz and 0.25 mm coupling gap. An efficiency of 96.3% is achieved. A simple frequency tracking unit is also proposed to tune the operating frequency in response to changes in the coupling gap. With this resonant frequency tracking unit, the efficiency of the proposed CPT system can be maintained within 96.3%-91% for the coupling gap range of 0.25-2 mm.

• Archives of Plastic Surgery
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• v.32 no.3
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• pp.319-326
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• 2005

This study was designed to investigate the optimal period of pedicles implantation in the prefabricated periosteofascial flap using a vascular tissue transfer. Flap prefabrication was prepared with a transposition of the central pedicles of right auricle on the calvarium of the New Zealand white rabbit. Thirty flaps were divided into five groups of six flaps, including control group (group I) of the conventional periosteofascial flap based on the right lateral border of parietal bone. The prefabricated flap was elevated as a $2{\times}2cm$ sized island flap and reposed in place in 1, 2, 3, and 4 weeks after the pedicles transfer in groups II, III, IV, and V, respectively. Five days after flap repositioning, the flap viability and vascularity were evaluated with microangiography and histological study quantitatively. The flap survival was increased in accordance with the implanted period of the pedicle. New vessels developed around the implanted pedicle in the 2nd week, and overall vascularization of the flap was accomplished in the 3rd week. The flap with 4 weeks of implantation period, however, showed the same survival rate as the control group. In conclusion, prefabricated periosteo- fascial flap can be created with a vascular tissue transfer, and the optimal duration of the pedicle implantation is more than 4 weeks to obtain adequate flap survival.

• Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
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• 2001.06a
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• pp.1127-1127
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• 2001

The transfer of predictive models using various chemometric techniques has been reported for FTNIR and scanning-grating based NIR instruments with respect relatively dry samples (<10% water). Some of the currently used transfer techniques include slope and bias correction (SBC), direct standardization (DS), piecewise direct standardization (PDS), orthogonal signal correction (OSC), finite impulse transform (FIR) and wavelet transform (WT) and application of neural networks. In a previous study (Greensill et at., 2001) on calibration transfer for wet samples (intact melons) across silicon diode array instrumentation, we reported on the performance of various techniques (SBC, DS, PDS, double window PDS (DWPDS), OSC, FIR, WT, a simple photometric response correction and wavelength interpolative method and a model updating method) in terms of RMSEP and Fearns criterion for comparison of RMSEP. In the current study, we compare these melon transfer results to a similar study employing pairs of spectrometers for non-invasive prediction of soluble solid content of peaches.

• Proceedings of the KSRS Conference
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• v.1
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• pp.336-339
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• 2006

In this paper, the preliminary transfer orbit analysis results for the COMS mission were presented. As the first step of transfer orbit analysis, the preliminary analyses of LAE burn strategy, geometrical visibility, and launch window were performed. For the analysis process, all launcher nominates were divided into three groups according to the declination of LAE thrust angle. So, the three launch cases were assigned as the representative launcher of each group, respectively. They are Ariane-5, Atlas summer and winter launch cases. And all analyses were performed at the representative launcher of each group. One nominal and three back-up plans were considered for the establishment of LAE burn strategy. And for geometrical visibility analysis, four TT&C ground stations were considered. Finally, the preliminary launch window analysis was performed about the duration of one year from the first day of September 2008. The analysis results show that the all launch cases comply with the transfer orbit operation requirements.

• Proceedings of the KIEE Conference
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• 2005.04a
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• pp.218-220
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• 2005

This paper shows the analysis of the inductive power transfer system in conjunction with series resonant converter operating variable high frequency. Of particular interest is the sensitivity of the complete system to variations in operational frequency and parameters. In inductive power transfer system, electrical power is transferred from a prima교 winding in the form of a coil or track, to one or more isolated pick-up coils that may relative to the primary. The ability to transmit power without contact enables high reliability and easy maintenance that allows inductive power transfer system to be implemented in hostile environments. This technology has found application in many fields such as electric vehicles, PRT(Personal Rapid Transit) etc. The coupling between the primary and secondary is then presented to include the effects of parameter and operational frequency variation.

• Clinical and Experimental Reproductive Medicine
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• v.43 no.2
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• pp.133-138
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• 2016

Objective: To determine the incidence of embryo retention (ER) in the transfer catheter following embryo transfer (ET) in blastocyst transfer and investigate whether retransferring retained embryos has an impact on reproductive outcomes in patients undergoing in vitro fertilization-ET. Methods: We retrospectively analyzed the records of 1,131 blastocyst transfers, which comprised 223 single blastocyst transfer (SBT) and 908 double blastocyst transfer (DBT) cycles. Each SBT and DBT group was classified depending on whether ET was performed without retained embryos in the catheter during the first attempt (without-ER group) or whether any retained embryos were found following ET (ER group) for the purpose of comparing reproductive outcomes in a homogenous population. Results: The overall incidence of finding retained embryos was 2.8% (32/1,131). There were no retained embryos in SBT cycles. In DBT cycles, implantation rates (30.0% vs. 26.6%), positive ${\beta}-hCG$ rates (57.2% vs. 56.2%), clinical pregnancy rates (45.3% vs. 46.9%), and live birth rates (38.9% vs. 43.8%) were not significantly different between the without-ER and ER groups. There were no significant differences in the mean birth weight (g) $2,928.4{\pm}631.8$ vs. $2,948.7{\pm}497.8$ and the mean gestational age at birth ($269.3{\pm}17.2days$ vs. $264.2{\pm}25.7days$). A total of nine cases of congenital birth defects were found in this study population. Eight were observed in the without-ER group and one in the ER group. Conclusion: Our results suggest that retransfer of retained embryos does not have any adverse impact on reproductive outcomes in blastocyst transfer cycles. Furthermore, our results support finding that SBT might be advantageous for decreasing the incidence of retained embryos in catheters.