Browsing by Author "Hung, CC"

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A low-voltage low-distortion MOS sampling switch
(2005)
Yang, CY
;
Hung, CC
;
電信工程研究所
;
Institute of Communications Engineering
In order to reduce distortion due to variation of the gate overdrive and the threshold voltage, a novel low-voltage constant-resistance sampling switch is proposed in this paper. The technique to reduce nonlinearity can be used in a high resolution sample and hold circuit. TSMC 0.18um standard CMOS technology is utilized in this research. Results indicate that much lower Total Harmonic Distortion (THD) is achieved by the proposed circuit. The low THD meets the requirements in the application of the low-voltage low-distortion switched-capacitor circuits.
A reliable low-voltage low-distortion MOS analog switch
(2006-02-01)
Yang, CY
;
Hung, CC
;
電信工程研究所
;
Institute of Communications Engineering
A novel low-voltage low-distortion analog sampling switch is proposed in this letter. A "source tracker" techniuqe is used to distinguish the real source terminal of the sampling switch. The turn-on resistance of the sampling switch is kept exactly constant. The modified switch makes the rail-to-rail input signal swing possible for low voltage. TSMC 0.18 mu m standard CMOS technology is utilized in this research. Results indicate that much lower Total Harmonic Distortion (THD) is achieved by the proposed circuit. The low THD meets the requirements in the application of the low-voltage low-distortion switched-capacitor circuits.
Colonization of human immunodeficiency virus-infected outpatients in Taiwan with Candida species
(2005-04-01)
Hung, CC
;
Yang, YL
;
Lauderdale, TL
;
McDonald, LC
;
Hsiao, CF
To understand the Candida colonization of human immunodeficiency virus (HIV)-infected outpatients in Taiwan, we have conducted a prospective cohort study of Candida colonization and its risk factors at the National Taiwan University Hospital from 1999 to 2002. More than 50% of the patients were colonized with Candida species, and 12% developed symptomatic candidiasis. Patients colonized with fluconazole-resistant strains of Candida species had a higher prevalence of candidiasis than those colonized with susceptible strains. Our analysis found that antibiotic treatment and lower CD4(+) counts (< 200 cells/mm(3)) increased the rate of oropharyngeal candidiasis in HIV-infected patients, while antiretroviral therapy protected patients from the development of candidiasis.
Effect of prolonged HAART on oral colonization with Candida and candidiasis
(2006-01-20)
Yang, YL
;
Lo, HJ
;
Hung, CC
;
Li, YC
;
生物科技學系
Background: Progressive cell-mediated immunodeficiency with decrease of CD4+ lymphocyte count to less than or equal to 200 cells/mm(3) is a major risk factor for colonization with Candida species and development of candidiasis. Oropharyngeal candidiasis may occur in up to 90% of human immunodeficiency virus (HIV)-infected patients during the course of the disease. This study is to determine the effect of prolonged highly active antiretroviral therapy (HAART) on oropharyngeal colonization with Candida species and oral candidiasis. Methods: A prospective, longitudinal follow-up study in HIV-infected patients receiving HAART. Results: The mean CD4+ count increased from 232.5 to 316 cells/mm(3) and the proportion of patients whose CD4+ count less than 200 cells/mm(3) decreased from 50.0% to 28.9% (p = 0.0003) in patients receiving HAART for at least 2 years. The prevalence of oral candidiasis decreased from 10.6% to 2.1% (p = 0.004). The decrease in Candida colonization was less impressive, falling from 57.8% to 46.5% (p = 0.06). Of the 142 patients enrolled in at least two surveys, 48 (33.8%) remained colonized with Candida and 42 (29.6%) remained negative. In the remaining 52 patients, 34 switched from culture positive to negative, and an increase in CD4+ lymphocytes was noted in 91.2% of them. Among the 18 patients who switched from culture negative to positive, 61.1% also demonstrated an increase in CD4+ lymphocyte count (p = 0.01). Conclusion: These findings indicate that HAART is highly effective in decreasing oral candidiasis in association with a rise in CD4+ lymphocyte counts, but only marginally effective in eliminating Candida from the oropharynx.
Exploring regression for mining user moving patterns in a mobile computing system
(2005)
Hung, CC
;
Peng, WC
;
Huang, JL
;
資訊工程學系
;
Department of Computer Science
In this paper, by exploiting the log of call detail records, we present a solution procedure of mining user moving patterns in a mobile computing system. Specifically, we propose algorithm LS to accurately determine similar moving sequences from the log of call detail records so as to obtain moving behaviors of users. By exploring the feature of spatial-temporal locality, we develop algorithm TC to group call detail records into clusters. In light of the concept of regression, we devise algorithm MF to derive moving functions of moving behaviors. Performance of the proposed solution procedure is analyzed and sensitivity analysis on several design parameters is conducted. It is shown by our simulation results that user moving patterns obtained by our solution procedure are of very high quality and in fact very close to real user moving behaviors.
Molecular epidemiology of long-term colonization of Candida albicans strains from HIV-infected patients
(2006-04-01)
Li, SY
;
Yang, YL
;
Chen, KW
;
Cheng, HH
;
Chiou, CS
Twenty-one Candida albicans isolates from three HIV-infected patients were collected over a period of 3 years and characterized for fluconazole susceptibility, infectivity and genetic relatedness. Fluconazole resistance was found in five isolates, four exhibited dose-dependent susceptibility and the remainder were fully susceptible to this agent. Pulsed-field gel clectrophoresis of SfiI restriction digests of the genomic DNA from the isolates revealed that isolates from the same swab specimen were identical despite differences in Susceptibility to fluconazole and isolates recovered over time from the three patients retained clonally related DNA fingerprints within each patient. This small-scale study confirms the persistence of oral colonization of C. albicans strains in HIV-infected patients. Clinical data also suggests that the primary infecting strain may become a persistent colonist in the oral cavity once the immune function of the patient has been restored.
Simultaneous etching of polysilicon materials with different doping types by low-damage transformer-coupled plasma technique
(2002-09-01)
Hung, CC
;
Lin, HC
;
Wang, MF
;
Huang, TY
;
Shih, HC
The feasibility of simultaneously etching n(+), p(+), and undoped polysilicon (poly-Si) materials by a commercial transformer coupled plasma (TCP) reactor has been investigated in this study. Response surface methodology (RSM) was used to optimize process parameters including pressure, TCP source power, bias power, and Cl-2/HBr flow on the main etch step. Quantitative relationships between etching performance and process parameters were established. Our results indicate that there exists a process parameter window that meets the requirements of etching polysilicon with different doping types simultaneously. High etch rate, superior uniformity, good end point detection (EPD) characteristics and profile control can be simultaneously obtained with the optimized recipe, irrespective of the doping types. Furthermore, only minor plasma-induced damage is detected as monitored from antenna transistors' charge-to-breakdown (Q(bd)), threshold voltage and charge pumping current. (C) 2002 Elsevier Science B.V. All rights reserved.