• 한국통신학회논문지
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• 제33권8A호
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• pp.787-793
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• 2008

3GPP의 Evolved Packet System (EPS)는 LTE, HSPA/HSPA+는 물론 non-3GPP 네트워크까지 포함한 다양한 액세스 네트워크를 지원하는 all-IP 기반 시스템이다. 최근, 패킷수준 QoS를 지원하는 IP flow에 대한 요구사항이 EPS에 추가되었다. 본 논문에서는 이러한 패킷수준 QoS 요구사항을 3G LTE에서 효과적으로 지원하기 위한 adaptive modulation coding (AMC) 선택 기법을 제안한다. 제안방법에서는 전송오류께 따른 재전송을 패킷 QoS 만족에 가장 큰 영향을 끼치는 요소로 보고, 패킷별로 다른 최대 패킷전송 오류 확률 $P_{max}$를 적용하여 AMC 전송 모드를 선정하는 기준으로 삼는다. 이러한 $P_{max}$를 결정할 때는 채널 상황은 물론 패킷별 QoS 요구상황, 그리고 NACK-to-ACK 에러 확률을 고려하여 결정한다. 이러한 방식의 목적은 QoS를 만족시키면서 동시에 spectral efficiency를 최대로 하는 것이다. 시뮬레이션을 통해 제안한 방법과 기존 방법을 비교한 결과, 지연허용 시간 위반과 재전송과 관련깊은 status report 발생은 10% 감소하고, throughput이 12% 증가했음을 확인할 수 있었다.

• 정보와 통신
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• 제25권9호
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• pp.3-8
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• 2008

본고에서는 1998년 말부터 시작된 3GPP의 표준인 WCDMA, HSPA 및 LTE로의 진화 로드맵을 알아보고, 특히 최근의 중점 이슈인 LTE에 대한 추진 배경, 일반적 요구사항 및 기술적 요구사항의 개요에 대해 알아본다. LTE는 2004년 말에 필요성이 제기되어 2005년부터 본격 추진되었고 2008년 말이면 무선접속 분야는 표준이 거의 완료될 전망이다. 과거 WCDMA 에서 HSPA로 진화 시 호환성을 고려해서 조심스럽게 접근했던 것과는 달리 LTE에서는 호환성의 제약을 받지 않는 완전히 새로운 표준을 지향하여, 단순하면서도 효율적이고 유연한 기술표준을 목표로 작업이 수행되어 왔다. 무선통신 분야의 주류 기술이 되고 있는 OFDM, MIMO기술을 바탕으로 LTE기술은 Vodafone, Verizon, NTT DoCoMo등 많은 대형사업자로부터 차세대 기술로 선택되고 있으며 2010년경부터 상용화가 예상되고 있다.

• Journal of Communications and Networks
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• 제14권3호
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• pp.273-279
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• 2012

In this paper, we propose an iterative interstream interference cancellation technique for system with frequency selective multiple-input multiple-output (MIMO) channel. Our method is inspired by the fact that the cancellation of the interstream interference can be regarded as a reduction in the magnitude of the interfering channel. We show that, as iteration goes on, the channel experienced by the equalizer gets close to the single input multiple output (SIMO) channel and, therefore, the proposed SIMO-like equalizer achieves improved equalization performance in terms of normalized mean square error. From simulations on downlink communications of $2{\times}2$ MIMO systems in high speed packet access universal mobile telecommunications system standard, we show that the proposed method provides substantial performance gain over the conventional receiver algorithms.

• 한국전자통신학회논문지
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• 제9권4호
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• pp.491-498
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• 2014

무선 접속을 통한 인터넷 서비스가 보편화된 최근 사람이 서비스를 이용하는 과정에서 실제로 느끼는 품질인 사용자 체감 품질(QoE; Quality of Experience)의 중요성이 더욱 강조되고 있는데 사용자 체감 품질은 서비스 품질 (QoS; Quality of Service)와 같이 객관적인 수치화가 불가능하다는 특징이 있다. 유선과는 달리 무선 접속을 통해서 제공되는 IP 서비스는 매우 많은 요인에 의해서 사용자 체감 품질이 영향을 받을 수 있다. 따라서 본 논문에서는 대표적인 무선 접속 서비스인 HSPA (High Speed Packet Access)를 통해서 음성 서비스가 제공될 때 측정 가능한 품질지표를 선정하고 이들에 대한 실측값을 통계적으로 분석하여 서비스 품질과 사용자 체감 품질 지표와의 상관관계를 밝히고자 한다. 분석 결과 RSSI (Received Signal Strength Indicator)와 전송 지연의 상관관계가 매우 높고 그에 이어 전송 지연과 MOS (Mean Opinion Score)와 매우 높은 상관관계를 가짐을 알 수 있었다.

• Journal of Microbiology and Biotechnology
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• 제29권7호
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• pp.1155-1164
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• 2019

Lichens contain diverse bioactive secondary metabolites with various chemical and biological properties, which have been widely studied. However, details of the inhibitory mechanisms of their secondary metabolites against influenza A virus (IAV) have not been documented. Here, we investigated the antiviral effect of lichen extracts, obtained from South Korea, against IAV in MDCK cells. Of the lichens tested, Nipponoparmelia laevior (LC24) exhibited the most potent inhibitory effect against IAV infection. LC24 extract significantly increased cell viability, and reduced apoptosis in IAV-infected cells. The LC24 extract also markedly reduced (~ 3.2 log-fold) IAV mRNA expression after 48 h of infection. To understand the antiviral mechanism of LC24 against IAV, proteomic (UPLC-$HDMS^E$) analysis was performed to compare proteome modulation in IAV-infected (V) vs. mock (M) and LC24+IAV (LCV) vs. V cells. Based on Ingenuity Pathway Analysis (IPA), LC24 inhibited IAV infection by modulating several antiviral-related genes and proteins (HSPA4, HSPA5, HSPA8, ANXA1, ANXA2, $HIF-1{\alpha}$, AKT1, MX1, HNRNPH1, HNRNPDL, PDIA3, and VCP) via different signaling pathways, including $HIF-1{\alpha}$ signaling, unfolded protein response, and interferon signaling. These molecules were identified as the specific biomarkers for controlling IAV in vitro and further confirmation of their potential against IAV in vivo is required. Our findings provide a platform for further studies on the application of lichen extracts against IAV.

• Asian Pacific Journal of Cancer Prevention
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• 제15권16호
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• pp.6855-6861
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• 2014

Background: Previous epidemiological studies have suggested a potential role of the $HSPA1B{\pm}1267A/G$ polymorphism in risk of developing cancer. However, the results were inconsistent. Therefore, we performed this meta-analysis to summarize the possible association with cancer risk. Materials and Methods: We retrieved relevant articles from PubMed, EMBASE, ISI Web of Science, Chinese Biomedical Literature and Chinese National Knowledge Infrastructure. Studies were selected using specific criteria. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to assess those associations. All analyses were performed using STATA software. Results: Fourteen case-control studies, including 1, 834 cancer cases and 2, 028 controls were included in this meta-analysis. Overall, the results indicated that the G allele of HSPA1B gene ${\pm}1267A/G$ was significantly associated with an increased cancer risk in all genetic models (G vs A: OR=1.51, 95%CI 1.17-1.95, p=0.001; GG vs AA: OR=2.93, 95%CI 1.50-5.74, p=0.002; AG vs AA: OR=1.48, 95%CI 1.10-1.98, p=0.009; GG/AG vs AA: OR=1.69, 95%CI 1.22-2.33, p=0.001; GG vs AG/AA: OR=2.31, 95%CI 1.24-4.32, p=0.009). In the subgroup analysis stratified by ethnicity, a significant association was identified in Caucasians (G vs A: OR=1.35, 95%CI 1.08-1.69, p=0.008; GG/AG vs AA: OR=1.36, 95%CI 1.09-1.70, p=0.007), but not in Asians. In the stratified analysis by cancer types, individuals with the G allele showed an increased risk of hepatocellular carcinoma compared with carriers of the A allele (OR=2.40, 95%CI 1.47-3.91, p<0.001). Inversely, individuals with the GG genotype showed a decreased risk of gastric cancer compared with carriers of the AG/GG genotypes (GG vs AG/AA: OR=0.39, 95%CI 0.20-0.70, p=0.007). Conclusions: This meta-analysis suggests associations between the HSPA1B ${\pm}1267A/G$ polymorphism and risk of cancer. However, this association might be Caucasian-specific and the G allele of this polymorphism probably increases risk of hepatocellular carcinoma while decreasing risk of gastric cancer. Further well-designed studies based on larger sample sizes are needed to validate these findings.

• Asian Pacific Journal of Cancer Prevention
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• 제16권18호
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• pp.8227-8233
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• 2016

Background: To investigate polymorphisms in heat shock proteins A1B and A1L (HOM) and associated risk of oesophageal carcinoma in Northeast India. Materials and Methods: The study includes oesophageal cancer (ECA) patients attending general outpatient department (OPD) and endoscopic unit of Gauhati Medical College. Patients were diagnosed based on endoscopic and histopathological findings. Genomic DNA was typed for HSPA1B1267 and HSPA1L2437 SNPs using the polymerase chain reaction with restriction fragment length polymorphisms. Results: A total of 78 cases and 100 age-sex matched healthy controls were included in the study with a male: female ratio of 5:3 and a mean age of $61.4{\pm}8.5years$. Clinico-pathological evaluation showed 84% had squamous cell carcinoma and 16% were adenocarcinoma. Dysphagia grades 4 (43.5%) and 5 (37.1%) were observed by endoscopic and hispathological evaluation. The frequency of genomic variation of A1B from wild type A/A to heterozygous A/G and mutant G/G showed a positive association [chi sq=19.9, p=<0.05] and the allelic frequency also showed a significant correlation [chi sq=10.3, with cases vs. controls, OR=0.32, $p{\leq}0.05$]. The genomic variation of A1L from wild T/T to heterozygous T/C and mutant C/C were found positively associated [chi sq=7.02, p<0.05] with development of ECA. While analyzing the allelic frequency, there was no significant association [chi sq=3.19, OR=0.49, p=0.07]. Among all the risk factors, betel quid [OR=9.79, Chi square=35.0, p<0.05], tobacco [OR=2.95, chi square=10.6, p<0.05], smoking [OR=3.23, chi square=10.1, p<0.05] demonstrated significant differences between consumers vs. non consumers regarding EC development. Alcohol did not show any significant association [OR=1.34, chi square=0.69, p=0.4] independently. Conclusions: It can be concluded that the present study provides marked evidence that polymorphisms of HSP70 A1B and HSP70 A1L genes are associated with the development of ECA in a population in Northeast India, A1B having a stronger influence. Betel quid consumption was found to be a highly significant risk factor, followed by smoking and tobacco chewing. Although alcohol was not a potent risk factor independently, alcohol consumption along with tobacco, smoking and betel nut was found to contribute to development of ECA.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.2137-2142
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• 2003

One of the important performance metrics of the World Wide Web is how fast and precise a request from users will be serviced successfully. Shared Web Caching (SWC) is one of the techniques to improve the performance of the network system. In Shared Web Caching Systems, the key issue is on deciding when and where an item is cached, and also how to transfer the correct and reliable information to the users quickly. Such SWC distributes the items to the proxies which have sufficient capacity such as the processing time and the cache sizes. In this study, the Hot Spot Prediction Algorithm (HSPA) has been suggested to improve the consistent hashing algorithm in the point of the load balancing, hit rate with a shorter response time. This method predicts the popular hot spots using a prediction model. The hot spots have been patched to the proper proxies according to the load-balancing algorithm. Also a simulator is developed to utilize the suggested algorithm using PERL language. The computer simulation result proves the performance of the suggested algorithm. The suggested algorithm is tested using the consistent hashing in the point of the load balancing and the hit rate.

• 한국ITS학회 논문지
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• 제10권1호
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• pp.60-66
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• 2011

정보통신과 네트워크 기술의 발달로 교통의 효율성과 교통이용자의 안전성을 높이는 지능형교통시스템(ITS) 서비스가 다양하게 제공되고 있다. 이동하는 자동차에 ITS 서비스를 제공하기 위하여 DSRC, Wibro, HSPA, WAVE 등 다양한 통신 방식이 이용되고 있지만, 각 통신방식의 규격과 성능의 차이로 모든 서비스를 하나의 통신방식으로 이용하기에는 어려움이 많다. 본 논문은 끊임없는 ITS 서비스 제공을 위하여 다양한 통신방식을 번갈아 이용하는 시스템을 제안하였으며, 임베디드플랫폼 기반의 단말기에서 성능을 구현하였다.

• Genomics & Informatics
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• 제8권1호
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• pp.34-40
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• 2010

Radiofrequency (RF) radiation might induce the transcription of a certain set of genes as other physical stresses like ionizing radiation and UV. To observe transcriptional changes upon RF radiation, we exposed WI-38, human lung fibroblast cell to 1763 MHz of mobile phone RF radiation at 60 W/kg of specific absorption rate (SAR) for 24h with or without heat control. There were no significant changes in cell numbers and morphology after exposure to RF radiation. Using quantitative RT-PCR, we checked the expression of three heat shock protein (HSP) (HSPA1A, HSPA6 and HSP105) and seven stress-related genes (TNFRSF11B, FGF2, TGFB2, ITGA2, BRIP1, EXO1, and MCM10) in RF only and RF/HS groups of RF-exposed cells. The expressions of three heat shock proteins and seven stress-related genes were selectively changed only in RF/HS groups. Based on the expression of ten genes, we could classify thermal and non-thermal effect of RF-exposure, which genes can be used as biomarkers for RF radiation exposure.