http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Beamforming Optimization for Multiuser Two-Tier Networks
정영민,Tony Q. S. Quek,신현동 한국통신학회 2011 Journal of communications and networks Vol.13 No.4
With the incitation to reduce power consumption and the aggressive reuse of spectral resources, there is an inevitable trend towards the deployment of small-cell networks by decomposing a traditional single-tier network into a multi-tier network with very high throughput per network area. However, this cell size reduction increases the complexity of network operation and the severity of cross-tier interference. In this paper, we consider a downlink two-tier network comprising of a multiple-antenna macrocell base station and a single femtocell access point, each serving multiples users with a single antenna. In this scenario, we treat the following beamforming optimization problems: i) Total transmit power minimization problem; ii) mean-square error balancing problem; and iii) interference power minimization problem. In the presence of perfect channel state information (CSI),we formulate the optimization algorithms in a centralized manner and determine the optimal beamformers using standard convex optimization techniques. In addition, we propose semi-decentralized algorithms to overcome the drawback of centralized design by introducing the signal-toleakage plus noise ratio criteria. Taking into account imperfect CSI for both centralized and semi-decentralized approaches, we also propose robust algorithms tailored by the worst-case design to mitigate the effect of channel uncertainty. Finally, numerical results are presented to validate our proposed algorithms.
급성신우신염 환자의 혈장 Neutrophil Gelatinase-Associated Lipocalin 측정의 유용성
정영민,하철민,노기철,표창해 대한응급의학회 2014 대한응급의학회지 Vol.25 No.2
Purpose: Plasma neutrophil gelatinase-associated lipocalin(NGAL) is a biomarker that shows correlation with theseverity of acute infection and acute kidney injury (AKI). This study was conducted in order to determine the predictivevalue of NGAL in the emergency department for predictingthe severity of acute pyelonephritis. Methods: A retrospective study was conducted betweenOctober 2012 and May 2013. A total of 46 patients diagnosedwith acute pyelonephritis were enrolled in this study. Plasma NGAL was measured upon admission to the hospitaland clinical and laboratory data, CT were collected. Based on these data, we classified our patients accordingto two groups (high NGAL group: NGAL ≥400 ng/mL vslow NGAL group: NGAL <400 ng/mL) and we evaluated thecorrelation between clinical data, laboratory data, and CT. Results: Among the 46 patients, there were 45 femalepatients and the mean age was 59.0±20.4 years. Statistically significant differences in CT grades, hospitalstay, SIRS, and shock were observed between the NGALgroups. The area under the ROC curve for CT severity byNGAL was 0.890(95% CI, 0.796-0.985), which was betterthan CRP and MDRD GFR. NGAL levels showed correlationwith CRP (r=0.508; p<0.001) and MDRD GFR (r=-0.766, p<0.001). Conclusion: NGAL is a useful specific biomarker predictingseverity of acute pyelonephritis.
정영민,백성호,박영태 대한화학회 2017 Bulletin of the Korean Chemical Society Vol.38 No.1
We oligomerized 2,5-dibromo-1,1-diisopropyl-3,4-diphenyl-2,5-silole with dichloroalkylphenylsilanes utilizing n-BuLi to yield conjugated oligo[(1,1-diisopropyl-3,4-diphenyl-2,5-silolene)-co-(alkylphenylsilylene)]s. Gel permeation chromatography measurements confirm that the synthesized materials are oligomeric. In addition, the prepared oligomers show characteristic diene stretching bands at 1579–1599 cm−1 in their FT-IR spectra. Furthermore, the oligomers are highly soluble in common organic solvents such as tetrahydrofuran and chloroform. In tetrahydrofuran, the oligomers show strong maximum electronic absorption bands at 253–292 nm with molar absorptivities of 1.61 × 102 to 2.57 × 104 /cm M in their UV–vis electronic absorption spectra, indicating that the maxima are red-shifted by 5–8 nm compared to the 2,5-dibromo-1,1-diisopropyl-3,4-diphenyl-2,5-silole monomer, strong maximum electronic excitation bands at 292–312 nm, and strong maxima electronic emission bands at 385–396 nm in the emission fluorescence spectra. The emission and absorption spectra strongly suggest that the prepared silole-containing oligomers may be conjugated through the oligomer backbone. In particular, cyclic voltammetry measurements of oligo[(1,1-diisopropyl-3,4-diphenyl-2,5-silolene)-co-(diphenylsilylene)] deposited on a glassy carbon electrode in 1.0 M aqueous hydrogen chloride show two oxidation potentials at 0.98 and 1.61 V vs. Ag/Ag+, and two reduction potentials at 0.00 and −1.93 V vs. Ag/Ag+. The oligomers were stable on heating to 200 °C under nitrogen, as determined by thermogravimetric analysis, losing between 4% and 23% of their starting weights.