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Performance analysis of reconfigurable intelligent surface assisted systems under channel aging

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Intelligent and Converged Networks 2022年第1期3卷 74-85页

作者： Yan Zhang Jiayi Zhang derrick wing kwan ng Huahua Xiao Bo Ai School of Electronic and Information Engineering Beijing Jiaotong UniversityBeijing 100044China School of Electrical Engineering and Telecommunications University of New South WalesSydney 2052Australia. ZTE Corporation and State Key Laboratory of Mobile Network and Mobile Multimedia TechnologyShenzhen 518057China State Key Laboratory of Rail Traffic Control and Safety Beijing Jiaotong UniversityBeijing 100044China

Reconfigurable intelligent surfaces(RISs)have attracted significant attention due to their capability in customizing wireless communication environments to improve system *** this study,we investigate the performance of an RIS-assisted multi-user multiple-input single-output wireless communication system,considering the impact of channel aging caused by users’relative *** particular,first,we propose a model incorporating the joint effects of channel aging and channel estimation errors to investigate the performance of the RIS-assisted ***,we derive novel closed-form expressions for characterizing the sum spectral efficiency with zero-forcing *** our analysis,we unveil that an increase in the temporal channel correlation coefficient,the number of base station antennas,and the received power at the users could help improve system ***,increasing the number of reflecting elements M of the RIS generally yields a good system performance,but with a diminishing return when M is sufficiently ***,simulation results are presented to validate the accuracy of the analytical results.

关键词： reconfigurable intelligent surface(RIS) channel aging spectral efficiency

A Survey of Downlink Non-Orthogonal Multiple Access for 5G Wireless Communication Networks

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ZTE Communications 2016年第4期14卷 17-25页

作者： WEI Zhiqiang YUAN Jinhong derrick wing kwan ng Maged Elkashlan DIng Zhiguo The University of New South Wales SydneyNSW 2052Australia Queen Mary University of London London E1 4NSUK Lancaster University Lancaster LA14YWUK

Non-orthogonal multiple access （NOMA） has been recognized as a promising multiple access technique for the next generation cel-lular communication networks. In this paper, we first discuss a simple NOMA model with two users served by a single-carrier si-multaneously to illustrate its basic principles. Then, a more general model with multicarrier serving an arbitrary number of users on each subcarrier is also discussed. An overview of existing works on performance analysis, resource allocation, and multiple-in-put multiple-output NOMA are summarized and discussed. Furthermore, we discuss the key features of NOMA and its potential re-search challenges.

关键词： non-orthogonal multiple access (NOMA) successive interference cancellation (SIC) resource allocation multiple-input multiple-output (MIMO)

Association of time to prostate-specific antigen nadir and logarithm of prostate-specific antigen velocity after progression in metastatic prostate cancer with prior primary androgen deprivation therapy

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Asian Journal of Andrology 2017年第1期19卷 98-102页

作者： Jeremy YC Teoh James HL Tsu Steffi KK Yuen Peter KF Chiu Samson YS Chan Ka-wing Wong kwan-Lun Ho Simon SM Hou Chi-Fai ng Ming-Kwong Yiu Division of Urology Department of Surgery The Chinese University of Hong Kong Prince of Wales Hospital Shatin Hong Kong China Division of Urology Department of Surgery Queen Mary Hospital University of Hong Kong Hong Kong China.

We investigated the association of time to prostate-specific antigen nadir （TTPN） and logarithm of prostate-specific antigen velocity after progression Log（PSAVAP） in metastatic prostate cancer with prior primary androgen deprivation therapy （ADT）. All metastatic prostate cancer patients treated with primary ADT from 2000 to 2009 were reviewed. Patients who developed disease progression were included in the subsequent analyses. Patients were categorized into three groups according to their TTPN： TTPN of 〈3 months, 3-17 months, and 〉17 months. We compared the Log（PSAVAP） between the different TTPN groups using Mann-Whitney U-test and Kruskal-Wallis test. Further multiple linear regression analyses on Log（PSAVAP） were performed to adjust for other potential confounding factors. Among 419 patients who were treated with primary ADT, 306 patients developed disease progression with a median follow-up of 28 months, Longer TTPN was associated with lower Log（PSAVAP）（P = 0.008） within all subgroup analyses （TTPN of 〈3 vs 3-17 months, P = 0.020; TTPN of 3-17 vs 〉17 months, P = 0.009; and TTPN of 〈3 vs 〉17 months, P = 0.001）. Upon multiple linear regression analyses, baseline PSA （regression coefficient 0.001, P = 0.045）, PSA nadir （regression coefficient 0.002, P = 0.040）, and TTPN （regression coefficient -0.030, P = 0.001） were the three factors that were significantly associated with Log（PSAVAP）. In conclusion, a longer TTPN was associated with lower Log（PSAVAP） in metastatic prostate cancer patients following primary ADT. TTPN cut-offs at 3 months and 17 months appeared to have prognostic significance in predicting Log（PSAVAP）. TTPN may serve as a good prognostic indicator in deciding the treatment strategy in patients with disease progression.

关键词： androgen deprivation therapy prostate cancer prostate-specific antigen velocity after progression ti me to prostate-specific antigen nadir

MELAS, MIDD and Beyond: m.3243A>G MT-TL1 Mutation in Adult Patients

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International Journal of Clinical Medicine 2016年第7期7卷 487-495页

作者： Bun Sheng Man Kei Fong wing kwan ng Sammy Pak Lam Chen Chloe Miu Mak Department of Medicine & Geriatrics Princess Margaret Hospital Hong Kong China Department of Pathology Princess Margaret Hospital Hong Kong China

m.3243A>G MT-TL1 mutation is the most common mitochondrial DNA mutation that results in a wide spectrum of disorders in a maternally inherited pedigree. In adult patients, many present with symptoms and signs indistinguishable from acquired diseases and the correct diagnosis is often delayed after many years. Nevertheless, clues suggesting m.3243A>G usually exist early in the disease course but are only realized late. These hints, from the evolution of symptoms and signs, family background, investigation results, or a combination of these, enable the physician to make the correct diagnosis early, which is important for appropriate treatment and better patient care. As with other inheritable diseases, genetic counselling should be offered regarding the disease management, inheritance mode, recurrence risk, usefulness and limitations of genetic testing and reproductive options.

关键词： Mitochondrial Disease MELAS m.3243A>G

Quantitative hepatitis B surface antigen in predicting recurrence of hepatitis B-related hepatocellular carcinoma after liver transplantation

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Hepatoma Research 2018年第9期4卷 159-170页

作者： James Fung Danny Ka-Ho Wong Yasuhito Tanaka Regina Lo Tiffany Wong Kenneth Siu-Ho Chok AIbert Chi-Yan Chan Tan-To Cheung wing-Chiu Dai KeIvin ng Kevin ng Man kwan Irene ng Wai-Kay Seto Ching-Lung Lai Man-Fung Yuen Chung-Mau Lo The Liver Transplant Center Queen Mary HospitalHong KongChina Department of Medicine the University of Hong KongHong KongChina State Key Laboratory for Liver Research the University of Hong KongHong KongChina Department of Virology and Liver Unit Graduate School of Medical sciencesNagoya City UniversityNagoya 467-8601Japan Department of Pathology the University of Hong KongHong KongChina Department of Surgery the University of Hong KongHong KongChina

Aim:Recurrence of hepatocellular carcinoma (HCC) after liver transplantation (LT) for chronic hepatitis B (CHB) can be associated with reappearance of hepatitis B surface antigen (HBsAg). The current study determined the significance of HBsAg qualitatively and quantitatively using a highly sensitive assay in recurrent HCC after transplantation. Methods:Consecutive patients with HBV-related HCC with LT were included. Oral nucleos(t)ide analogues without hepatitis B immune globulin were used as hepatitis B virus (HBV) prophylaxis. Quantitative HBsAg levels were performed at time of transplant, at 1 month, 3 and 6 months post transplant using a highly sensitive (hs)-HBsAg assay. Results:One hundred and fourteen patients were included, with a median follow-up of 80 months, with 24 cases of HCC recurrence, and a cumulative rate of 20.7% at 5 years. There was significant correlation between time of tumor recurrence and time of HBsAg reappearance (r = 0.551,P = 0.027). Early HCC recurrence was associated with higher median level of hs-HBsAg at the time of transplant (72.85vs. 69.70 IU/mL,P = 0.018). Using a hs-HBsAg cut-off level of 0.0005 IU/mL, patients with levels above this threshold at 3 and 6 months were associated with higher rate of early HCC recurrence (28.6%vs. 3.0% and 26.9%vs. 2.9% respectively, bothP =0.0006). There was no significant difference in HCC recurrence between positive and negative HBsAg using the conventional qualitative HBsAg assay. Conclusion:Serum hs-HBsAg levels of≥ 0.0005 IU/mL at 3 to 6 months after LT is associated with higher rates of early HCC recurrence, and may be useful as an early tumor marker.

关键词： Hepatitis B hepatocellular carcinoma transplantation hepatitis B surface antigen recurrence

自来水中的药物:中国人类健康风险评估及监测建议框架

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环境与职业医学 2013年第10期30卷 773-773页

作者： Ho wing Leung Ling Jin Si Wei Mirabelle Mei Po Tsui Bingsheng Zhou Liping Jiao Pak Chuen Cheung Yiu Kan Chun Margaret Burkhardt Murphy Paul kwan Sing Lam

[背景]在世界范围内,已知药品会污染自来水,但是在中国尚无相关的人类健康风险评估。[目的]监测中国自来水中的32种药品,并评估暴露的终身人类健康风险,以便为未来的优先级管理和风险管理提供信息。[方法]作者分析来自13个城市的样本(n=... 详细信息

[背景]在世界范围内,已知药品会污染自来水,但是在中国尚无相关的人类健康风险评估。[目的]监测中国自来水中的32种药品,并评估暴露的终身人类健康风险,以便为未来的优先级管理和风险管理提供信息。[方法]作者分析来自13个城市的样本(n=113),并将检测到的浓度与现有或新得出的安全水平进行比较,以评估除产前期以外不同生命阶段的风险商数(RQs)。[结果]在89%的样本中检测到17种药品,大多数(92%)检出浓度ng/L。在≥20%的样本中检测到咖啡因(中等～最大浓度,24.4～564ng/L)、甲硝唑(1.8～19.3ng/L)、水杨酸(16.6～41.2ng/L)、氯贝酸(1.2～3.3ng/L)、卡马咪嗪(1.3～6.7ng/L)、二甲硝咪唑(6.9～14.7ng/L)。由于自来水中检测到药品水平及阳性频率均高,长江中下游地区城市和广州被视为受药品污染的重点区域。在检测到的17种药品中,13种为极低风险水平,但4种药品(二甲硝咪唑、甲砜霉素、磺胺二甲基嘧啶和克拉霉素)至少在一个生命阶段的RQ≥0.01,尤其是婴幼儿和儿童阶段,应被视为管理的高度优先级。本文提出了一个基于指标的监测框架,为中国的药品来源识别、水处理效果及水安全管理提供信息。[结论]中国的自来水是人体药品暴露另外的一个路径,特别是二甲硝咪唑,尽管基于当前的毒性数据,它对人体健康是低风险的。药品检测和监测建议框架可用于在中国和其他地方的水源保护和风险管理。

关键词：中国指标生命阶段药品风险管理自来水