• The Journal of the Korea institute of electronic communication sciences
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• v.10 no.5
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• pp.549-556
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• 2015

In this paper, design and fabrication for inset fed microstrip patch antennas applied to the $3{\times}3$ array CSLR and eight CSLR, respectively, to the ground plane are studied. The theoretical results are compared to the experimental results for the return loss and radiation pattern. For 'CSLR 09' antenna, the theoretical result for the resonant frequency and the return loss are 2.82 GHz and - 25.35 dB, respectively. The experimental results are obtained for a 2.885 GHz, -30.72 dB. Theoretical results for the resonant frequency and the return loss of the 'CSLR 08' antenna are 2.82 GHz, -16.77 dB, respectively, and the experimental results are obtained for a 2.885 GHz, -14.90 dB. In addition, E-plane and H-plane radiation patterns in comparison with designed and fabricated antennas are in good agreement.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.23 no.2
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• pp.163-173
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• 2020

Purpose: This study aimed to investigate the clinical and metabolic determinants of circulating soluble leptin receptor (CSLR) and free leptin index (FLI) in pre-pubertal obese male children. Methods: We conducted a preliminary cross-sectional study at three tertiary hospitals and one public primary school. Eighty obese male children without growth and developmental abnormalities aged 5-9 years were recruited. In these children, obesity was solely caused by excessive food intake, and not by acute illness, medications, endocrine abnormalities, or any syndrome. Body mass index (BMI), body fat mass, carbohydrate intake, fat intake, high density lipoprotein cholesterol level, low density lipoprotein cholesterol level, triglyceride level, and Homeostatic Model Assessment for Insulin Resistance are the potential determinants for leptin regulation, which is represented by CSLR level and FLI. Results: Carbohydrate was the main source of energy. BMI and body fat mass had negative weak correlation with CSLR and positive weak correlation with FLI. Furthermore, carbohydrate intake was found to be independently associated with CSLR based on the results of the multiple linear regression analysis. Following an increase in carbohydrate intake, CSLR level decreased progressively without any negative peak. Conclusion: Leptin regulation in prepubertal obese male children is associated with body composition and dietary intake. Carbohydrate intake is useful for predicting CSLR. Lipid profiles and insulin resistance are not related to both CSLR and FLI. Treatment and prevention of leptin resistance in obese children should focus on reducing BMI, fat mass, and carbohydrate intake.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.8
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• pp.921-926
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• 2014

In this paper, the characteristics of inset fed microstrip antenna loaded with CSLR(complementary single loop resonator) are studied. Effective permeability parameters of the SLR unit cell is retrieved from simulated scattering parameters, and structure parameters of the SLR unit cell are selected so that effective permeability is negative value at the operating frequency. The optimized inset fed microstrip antenna loaded with SLR for a $3{\times}3$ array in the ground plane of a conventional patch antenna is designed and simulation results of return loss and radiation pattern are shown. At resonant frequency 2.82 GHz, the overall dimension of the proposed antenna is reduced by approximately 56.8% compared to the conventional inset fed antenna. Simulation results are obtained by 3D FEM solver(Ansoft's HFSS).

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.11
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• pp.1047-1052
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• 2016

In this paper, we propose the CSLR(: Complementary Single Loop Resonators)-loaded inset fed patch antenna with a conducting reflector to improve the radiation patterns. Reflector of the proposed antenna is located below about ${\lambda}_0/4$ from the ground plane of the patch, the size is about two times of the patch. The proposed antenna is designed and fabricated on the substrate which has a dielectric constant and thickness with 2.5 and 0.787 mm, respectively. Simulation results are obtained by using the HFSS, 3D EM Solver based Finite Element Method(: FEM). The resonant frequency and matching characteristics of the antenna with reflector are substantially the same as when there is no change in the antenna without reflector, it is confirmed that radiation patterns are significantly improved by the reflector.

• Phonetics and Speech Sciences
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• v.6 no.4
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• pp.17-26
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• 2014

The present study examined epenthetic vowels produced by Korean learners of English in read sentences, in terms of acoustic measures and extra-phonological factors. The results demonstrated three main findings. First, epenthetic vowels had relatively high F1 values and a wide range of F2 values. Most of the epenthetic vowels were inserted near Korean high central vowels, but some vowels were inserted near front vowels due to co-articulation with surrounding vowels. Second, vowel epenthesis was affected by the context. The results showed that the epenthesis was frequently seen with word junctions between obstruents (e.g., stops-fricatives). Third, Korean learners were not affected by English background and were very weakly affected by orthography. English experience, which is one of the extra-phonological factors, was not related to epenthesis production. However, orthography, the other extra-phonological factor, very weakly affected the amount of epenthesis production. Nine percent of all epenthesis production was affected by the English past-tense suffix '-ed'; approximately 70% of the participants were affected by this suffix. The findings of the present study contributed to understanding vowel epenthesis. First, the study revealed that the epenthetic vowels produced by Korean learners of English were close to the high central vowel, supporting previous studies that the epenthetic vowel is quite close to the shortest vowel. Second, the study examined the various phonetic environments of epenthetic vowels, revealing that vowel epenthesis occurred more frequently in a certain phonetic circumstance.

• Phonetics and Speech Sciences
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• v.8 no.1
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• pp.37-44
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• 2016

The goal of the current study is to investigate how the sound change is reflected in production or in perception, and what the effect of lexical frequency is on the loss of sound contrasts. Specifically, the current study examined whether the vowel length contrasts are retained in Korean speakers' productions, and whether Korean listeners can distinguish vowel length minimal pairs in their perception. Two production experiments and two perception experiments investigated this. For production tests, twelve Korean native speakers in their 20s and 40s completed a read-aloud task as well as a map-task. The results showed that, regardless of their age group, all Korean speakers produced vowel length contrasts with a small but significant differences in the read-aloud test. Interestingly, the difference between long and short vowels has disappeared in the map task, indicating that the speech mode affects producing vowel length contrasts. For perception tests, thirty-three Korean listeners completed a discrimination and a forced-choice identification test. The results showed that Korean listeners still have a perceptual sensitivity to distinguish lexical meaning of the vowel length minimal pair. We also found that the identification accuracy was affected by the word frequency, showing a higher identification accuracy in high- and mid- frequency words than low frequency words. Taken together, the current study demonstrated that the speech mode (read-aloud vs. spontaneous) affects the production of the sound undergoing a language change; and word frequency affects the sound change in speech perception.

• Phonetics and Speech Sciences
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• v.9 no.2
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• pp.69-76
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• 2017

The current study investigated whether Korean learners' English-learning environments, especially target English accent (General American English (GAE) vs. Southern British English (SBE)) and English-language experience affected their production of English vowels. Thirty six EFL learners, 27 ESL-US learners, and 33 ESL-UK learners produced 8 English vowels with a bVt frame (beat, bit, bet, bat, bought, bot, boat, boot). The learners' productions were acoustically analyzed in terms of F1 and F2 frequencies. The overall results revealed that the learners' target accent had an effect on their production of some English vowels. The EFL and ESL-US learners' (especially, female learners') production of bought, bot, boat, and boot, which show characteristic differences between the GAE and SBE accents, was closer to that of the native American English (AE) speakers than the native British English (BE) speakers. In contrast, the ESL-UK learners' production of bought and bot demonstrated the opposite pattern. Thus, the impact of target accent was not demonstrated across the board. The effect of the learners' different English-language experience was also rather limited. This was because the EFL learners' production was not much different from the ESL-US learners' production, in spite of the ESL-US learners' residence in the US for more than 9 years. Furthermore, the Korean learners, irrespective of their different English-language experience, tended to produce bit and bat with lower F1 than the native AE and BE speakers, thus resulting in bit and bat to be produced similarly to beat and bet, respectively. This demonstrates the learners' persistent L1 effects on their English vowel production despite the learners' residence in the English speaking countries or their high English proficiency.