• Journal of the Institute of Electronics and Information Engineers
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• v.49 no.10
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• pp.47-53
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• 2012

Time-reversal (TR) precoding focuses the energy of the effective channel in time and improves receive performance of a single tap receiver. Frequency-domain equal-gain-combining (FD-EGC) TR scheme, which works in linear block precoding fashion, has better temporal focusing performance than the traditional TR. Also, the FD-EGC improves receive performance of minimum mean square error receiver with distributed antenna systems (DAS). The detailed receive performance of the FD-EGC was analyzed in our previous work. In this paper, we focused on capacity analysis of the FD-EGC in DAS. We derived a scaling law which shows how the use of multiple antenna can increase the capacity of the FD-EGC precoding compared with that of no precoding. In addition, we analyze the secrecy rate of the FD-EGC which shows how high-rate messages can be transmitted towards an intended user without being decoded by the other users from the view point of information theoretic security.

• Journal of Applied Biological Chemistry
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• v.60 no.3
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• pp.199-205
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• 2017

To investigate the anti-inflammatory activity of natural products, we determined the anti-inflammatory activity of purified epigallocatechin (EGC) from Camellia sinensis leaves. In the present study, we found that EGC inhibited the production of proinflammatory mediators (IL-6, TNF-${\alpha}$, NO, and $PGE_2$) in lipopolysaccharide (LPS)-stimulated Raw 264.7 cells. Suppression of IL-6 seems to be at least partly attributable to the inhibitory effect of EGC. TNF-${\alpha}$ is a major cytokine produced by LPS-induced macrophages, and they have a wide variety of biological functions including regulation of inflammation. The inhibition of IL-6 and TNF-${\alpha}$ production by EGC may downregulate the acute-phase response to LPS, thereby reducing LPS-induced inflammation. In addition to IL-6 and TNF-${\alpha}$, EGC effectively reduced the production of other key inflammatory mediators, including NO and $PGE_2$. The inhibitory effect of EGC on NO and $PGE_2$ production was supported by the suppression of inducible nitric oxide synthase and COX-2 at protein levels. These results support the traditional use of EGC in the alleviation of various inflammation-associated diseases and suggest that EGC might be useful in the development of new functional foods for inflammatory diseases.

• The Journal of the Korea Contents Association
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• v.12 no.11
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• pp.278-285
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• 2012

In an experiment in which fermentation was done by adding fungal species that have antibiosis but do not have cellulase, the extraction amount of EGC, EC, EGCG, and ECG increased in all samples that fermented by adding sun-dried salt compared to those that fermented only with green tea after fermenting green tea by mixing it with sun-dried salt. In the analysis conducted according to the days of fermentation, the high extraction amounts of EGC(epigallocatechin), ECG(epicatechin gallate), EC(epicatechin), and EGCG(epigallocatechin gallate) were detected on the second and third day. Furthermore, when fermentation was done by adding ferment bacillus, all types of catechin(EGC, EC, EGCG, ECG) extraction increased in Paenibacillus spp but in Bacillus amyloliquefaciens, EGC and EC decreased while EGCG and ECG increased; whereas in Bacillus pumilus and Bacillus subtilis all types of catechin(EGC, EC, EGCG, ECG) decreased. The results of the above experiment reveal that the largest amount of catechin was extracted from the result which conducted fermentation for three days together with sun-dried salt and Paenibacillus spp in the green tea.

• Journal of Gastric Cancer
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• v.23 no.1
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• pp.146-158
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• 2023

Endoscopic resection (ER) is widely performed for early gastric cancer (EGC) with a negligible risk of lymph node metastasis (LNM) in Eastern Asian countries. In particular, endoscopic submucosal dissection (ESD) leads to a high en bloc resection rate, enabling accurate pathological evaluation. As undifferentiated EGC (UD-EGC) is known to result in a higher incidence of LNM and infiltrative growth than differentiated EGC (D-EGC), the indications for ER are limited compared with those for D-EGC. Previously, clinical staging as intramucosal UD-EGC ≤2 cm, without ulceration, was presented as 'weakly recommended' or 'expanded indications' for ER in the guidelines of the United States, Europe, Korea, and Japan. Based on promising long-term outcomes from a prospective multicenter study by the Japan Clinical Oncology Group (JCOG) 1009/1010, the status of this indication has expanded and is now considered 'absolute indications' in the latest Japanese guidelines published in 2021. In this study, which comprised 275 patients with UD-EGC (cT1a, ≤2 cm, without ulceration) treated with ESD, the 5-year overall survival (OS) was 99.3% (95% confidence interval, 97.1%-99.8%), which was higher than the threshold 5-year OS (89.9%). Currently, the levels of evidence grades and recommendations for ER of UD-EGC differ among Japan, Korea, and Western countries. Therefore, a further discussion is warranted to generalize the indications for ER of UD-EGC in countries besides Japan.

• Journal of Gastric Cancer
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• v.17 no.4
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• pp.331-341
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• 2017

Purpose: This study aimed to evaluate the clinical significance of microscopic invasion to determine the adequate resection margin in early gastric cancer (EGC). Materials and Methods: A retrospective review was performed that included patients who underwent gastrectomy for clinical early gastric cancer (cEGC) at Seoul National University Hospital between January 2007 and December 2010. After subtracting the microscopic resection margin from the gross resection margin for each proximal or distal resection margin, microscopic invasion was represented by the larger value. Microscopic invasion and its risk factors were analyzed according to the clinicopathologic characteristics. Results: In total, 861 patients were enrolled in the study. Microscopic invasion of cEGC was $6.0{\pm}12.8mm$, and the proportion of patients with microscopic invasion ${\geq}0mm$ was 78.4%. In the risk group, tumor location, pT stage, and differentiation did not significantly discriminate the presence of microscopic invasion. The microscopic invasion of EGC-IIb was $13.9{\pm}16.8mm$, which was significantly greater than that of EGC-I. No linear correlation was observed between the overall tumor size and microscopic invasion (R=0.030). The independent risk factors for microscopic invasion ${\geq}20mm$ were EGC-IIb vs. EGC-I/IIa/IIc/III (odds ratio [OR], 3.103; 95% confidence interval [CI], 1.533-6.282; P=0.002) and male vs. female sex (OR, 1.655; 95% CI, 1.012-2.705; P=0.045). Conclusions: Male sex and EGC-IIb were independent risk factors for microscopic invasion ${\geq}20mm$. Examination of intraoperative frozen sections is highly recommended to avoid resection margin involvement, especially in cases of EGC-IIb.

• Journal of Gastric Cancer
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• v.11 no.3
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• pp.146-154
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• 2011

Endoscopic resection has been accepted as a curative modality for early gastric cancer (EGC). Since conventional endoscopic mucosal resection (EMR) has been introduced, many improvements in endoscopic accessories and techniques have been achieved. Recently, endoscopic submucosal dissection (ESD) using various electrosurgical knives has been performed for complete resection of EGC and enables complete resection of EGC, which is difficult to completely resect in the era of conventional EMR. Currently, ESD is accepted as the standard method for endoscopic resection of EGC in indicated cases. In this review, the history of endoscopic treatment for EGC, overall ESD procedures, and indications and clinical results of endoscopic treatment will be presented.

• Journal of Satellite, Information and Communications
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• v.12 no.2
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• pp.38-41
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• 2017

Reception performance in land mobile satellite is decreased by obstacle. It is compensated with Diversity technique. In this paper, performances are analyzed with two type of method Equal Gain Combining(EGC) and Selcetive Combining(SC). To analyze, measured data using On-The-Move(OTM) terminal are used. In conclusion, SC method can increase performance. However, EGC method can improve perforamance only in rural region, but performance are decreased in urban region.

• Journal of Gastric Cancer
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• v.21 no.3
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• pp.246-257
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• 2021

Purpose: It is unclear whether high-definition (HD) imaging improves visibility and diagnostic ability in early gastric cancer (EGC) compared with standard-definition (SD) imaging. We aimed to compare the diagnostic performance and visibility scores of HD and SD ultraslim endoscopes in EGC. Materials and Methods: We used HD and SD ultraslim endoscopes to obtain 60 images with similar compositions of gastric environments. Of the 60 images, 30 showed EGC (15 images for each modality) and 30 showed no EGC (15 images for each modality). Seventeen endoscopists evaluated the presence and location of the lesions in each image. Diagnostic ability was compared between modalities. The color difference between a lesion and the surrounding mucosa (ΔE) was measured and compared between the modalities. Results: The ability of HD to detect EGC was significantly higher than that of SD (accuracy: 80.8% vs. 71.6%, P=0.017; sensitivity: 94.9% vs. 76.5%, P<0.001; positive predictive value, 76.2% vs. 55.3%, P<0.001; and negative predictive value (NPV), 94.1% vs. 73.5%, P<0.001). The ability of HD to determine the horizontal extent of EGC was significantly higher than that of SD (accuracy: 71.0% vs. 57.8%, P=0.004; sensitivity: 75.3% vs. 49.0%, P<0.001; NPV, 72.9% vs. 55.9%, P<0.001; and area under the curve: 0.891 vs. 0.631, P=0.038). The mean ΔE was significantly higher for HD than for SD (10.3 vs. 5.9, P=0.011). Conclusions: The HD ultraslim endoscope showed a higher diagnostic performance in EGC than the SD endoscope because it provided good color contrast.

• Journal of Gastric Cancer
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• v.18 no.2
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• pp.152-160
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• 2018

Purpose: Totally laparoscopic gastrectomy (TLG) for advanced gastric cancer (AGC) is a technically and oncologically challenging procedure for surgeons. This study aimed to compare the oncologic feasibility and technical safety of TLG for AGC versus early gastric cancer (EGC). Materials and Methods: Between 2011 and 2016, 535 patients (EGC, 375; AGC, 160) underwent curative TLG for gastric cancer. Clinicopathologic characteristics and surgical outcomes of both patient groups were analyzed and compared. Results: Patients with AGC required a longer operation time and experienced more intraoperative blood loss than those with EGC did. However, patients from both the AGC and EGC groups demonstrated similar short-term surgical outcomes such as postoperative morbidity (14.4% vs. 13.3%, P=0.626), mortality (0% vs. 0.5%, P=0.879), time-to-first oral intake (2.7 days for both groups, P=0.830), and postoperative hospital stay (10.2 days vs. 10.1 days, P=0.886). D2 lymph node dissection could be achieved in the AGC group (95%), with an adequate number of lymph nodes being dissected ($36.0{\pm}14.9$). In the AGC group, the 3-year overall and disease-free survival rates were 80.5% and 73.7%, respectively. Conclusions: TLG is as safe and effective for AGC as it is for EGC.

• Journal of the Korea Society of Computer and Information
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• v.11 no.5 s.43
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• pp.195-201
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• 2006

In multicarrier code division multiple access(MC-CDMA), the total system bandwidth is divided into a number of sub-bands, where each subband may use direct-sequence(DS) spreading and each subband signal is transmitted using a subcarrier frequency. In this paper, the system performance analysis of MC-CDMA using to gain combining(EGC) and maximal ratio combining(MRC) method over frequency selective Nakagami-m fading channel is analyzed. In the proposed system, a data sequence is serial-to-parallel converted, and MC-CDMA is used on each of the parallel data streams. The data streams are spread at both the symbol fraction level and at the chip level by the transmitter. In this paper, the compare to analysis,two standard diversity combining techniques, EGC and MRC, The good performance of system using to MRC more than EGC