BACKGROUND Human immunodeficiency virus(HIV)recency testing provides data that can be used to monitor the trend of new HIV infections.The effectiveness of using people identified with recent infection to identify part...BACKGROUND Human immunodeficiency virus(HIV)recency testing provides data that can be used to monitor the trend of new HIV infections.The effectiveness of using people identified with recent infection to identify partners with new HIV infection through partner notification services(PNS)is not well documented.AIM To determine the pooled prevalence of recency testing coverage,recent infection,reclassification(recent to longterm infection)and PNS cascade among newly diagnosed people living with HIV.METHODS PubMed,Cochrane Library and Embase were searched for articles published between January 2018 and November 2024.Studies were included if they reported recency coverage and/or PNS among people newly diagnosed with HIV and used recent infection testing algorithm(RITA).Recency coverage was defined as proportion of people tested using rapid testing for recent infection(RTRI)among those newly diagnosed with HIV.RITA further classifies RTRI results using viral load results(≥1000 copies/mL vs<1000 copies/mL)to confirm recency status.For studies with PNS,we evaluated the cascade:Number of partners elicited,successfully contacted,eligible for HIV testing,tested and HIV diagnosis.PNS effectiveness was measured by proportion of new HIV diagnoses from tested partners.Using random effects models,we computed the pooled estimate of recency outcomes and 95%confidence intervals(CIs).RESULTS Twenty-five studies from 17-low-and middle-income countries were included.Of 276315 newly diagnosed people living with HIV,79864 underwent RTRI with an overall pooled recency coverage of 87%(95%CI:67-96).The pooled prevalence of RTRI and RITA recency were 12%(95%CI:9-16)and 7%(95%CI:4-10),respectively.Pooled prevalence of RTRI reclassification was 34%(95%CI:22-49).Of the recent cases who agreed to PNS,253 partners were elicited with an estimated elicitation ratio of 1:1.6.Among partners elicited,99%were successfully contacted,75%were eligible for testing,68%tested for HIV,and 15%were diagnosed with HIV.CONCLUSION High recency testing coverage among newly diagnosed individuals demonstrates the feasibility of monitoring new HIV infections in LMIC.While PNS yielded moderate HIV diagnoses,its targeted approach remains a critical strategy for identifying undiagnosed cases.展开更多
We have established an elastoplastic analysis model to explore the effect of loading path in an incompressible thin-walled tube under the combined action of axial force and torque based on Mises yield condition and is...We have established an elastoplastic analysis model to explore the effect of loading path in an incompressible thin-walled tube under the combined action of axial force and torque based on Mises yield condition and isotropic linear hardening assumption.Further,four stress areas(σx,τx)are divided according to the characteristics of the final stress,and the plastic stress-strain relationship of twelve stress paths in different stress areas is derived.The"primary effect"of the stress path on plastic strain is demonstrated,namely,the plastic strain caused by the pre-loaded stress in path A(tensile stress is initially applied,followed by shear stress)is always greater than that caused by the post-loaded stress in path C(shear stress is initially applied,followed by tensile stress)irrespective of the value of final stress.The"recency effect"of the strain path on the stress is also established,which indicates that the stress caused by the post-loaded strain in path A is always greater than that caused by the pre-loaded strain in path C irrespective of the value of final strain.From the perspective of deformation,the"primary effect"of the stress path on the plastic strain and the"recency effect"of the strain path on the stress are unified.These effects are succinct and universal,and they provide useful insights on the plastic stress-strain relationship under different loading paths.Furthermore,they can serve as a useful reference for optimizing the processing technologies and construction procedures.展开更多
In the big data era,data unavailability,either temporary or permanent,becomes a normal occurrence on a daily basis.Unlike the permanent data failure,which is fixed through a background job,temporarily unavailable data...In the big data era,data unavailability,either temporary or permanent,becomes a normal occurrence on a daily basis.Unlike the permanent data failure,which is fixed through a background job,temporarily unavailable data is recovered on-the-fly to serve the ongoing read request.However,those newly revived data is discarded after serving the request,due to the assumption that data experiencing temporary failures could come back alive later.Such disposal of failure data prevents the sharing of failure information among clients,and leads to many unnecessary data recovery processes,(e.g.caused by either recurring unavailability of a data or multiple data failures in one stripe),thereby straining system performance.To this end,this paper proposes GFCache to cache corrupted data for the dual purposes of failure information sharing and eliminating unnecessary data recovery processes.GFCache employs a greedy caching approach of opportunism to promote not only the failed data,but also sequential failure-likely data in the same stripe.Additionally,GFCache includes a FARC(Failure ARC)catch replacement algorithm,which features a balanced consideration of failure recency,frequency to accommodate data corruption with good hit ratio.The stored data in GFCache is able to support fast read of the normal data access.Furthermore,since GFCache is a generic failure cache,it can be used anywhere erasure coding is deployed with any specific coding schemes and parameters.Evaluations show that GFCache achieves good hit ratio with our sophisticated caching algorithm and manages to significantly boost system performance by reducing unnecessary data recoveries with vulnerable data in the cache.展开更多
为了解决传统K-means算法对初始聚类中心敏感和聚类数目事先难以确定的问题,提出了一种改进的K-means算法。改进算法利用最大距离等分策略来选取初始聚类中心,并利用一种评价函数来自动确定聚类数,减少了算法结果对参数的依赖。将改进...为了解决传统K-means算法对初始聚类中心敏感和聚类数目事先难以确定的问题,提出了一种改进的K-means算法。改进算法利用最大距离等分策略来选取初始聚类中心,并利用一种评价函数来自动确定聚类数,减少了算法结果对参数的依赖。将改进算法应用到某企业客户分类中时,为提高分类结果的表征性,提出了以客户最近购买时间(Recency)、购买频次(Frequency)、平均购买额(Average Monetary)和购买倾向(Trend)作为客户价值细分变量的RFAT(Recency,frequency,average monetary and trend)模型,对客户RFAT值进行了聚类分析,并提供了针对不同客户群的营销策略。实证研究表明,该文所提出的改进算法和模型可以有效地对企业客户进行分类,能充分反映客户的当前价值和增值潜能。展开更多
针对通过零售交易数据进行客户分群时传统方法未考虑商品的价值问题,提出用RFM(recency frequency monetary)表达交易数据的方法,该方法将客户购买的商品和商品类别组成一棵RFM购买树(recency frequency monetary purchase tree,RFMPT)...针对通过零售交易数据进行客户分群时传统方法未考虑商品的价值问题,提出用RFM(recency frequency monetary)表达交易数据的方法,该方法将客户购买的商品和商品类别组成一棵RFM购买树(recency frequency monetary purchase tree,RFMPT).提出基于RFM购买树的快速聚类算法(based recency frequency monetary purchase tree clustering,BRFMPTC),把购买树构建为Cover Tree(CT)索引结构,利用CT结构快速选择k个密度最大的购买树作为中心,将其他对象划分到距它最近的类中心.实验结果表明,在距离加权下,BRFMPTC算法较传统算法在整体上能产生质量更高的聚类结果,性能得到较大提升.展开更多
文摘BACKGROUND Human immunodeficiency virus(HIV)recency testing provides data that can be used to monitor the trend of new HIV infections.The effectiveness of using people identified with recent infection to identify partners with new HIV infection through partner notification services(PNS)is not well documented.AIM To determine the pooled prevalence of recency testing coverage,recent infection,reclassification(recent to longterm infection)and PNS cascade among newly diagnosed people living with HIV.METHODS PubMed,Cochrane Library and Embase were searched for articles published between January 2018 and November 2024.Studies were included if they reported recency coverage and/or PNS among people newly diagnosed with HIV and used recent infection testing algorithm(RITA).Recency coverage was defined as proportion of people tested using rapid testing for recent infection(RTRI)among those newly diagnosed with HIV.RITA further classifies RTRI results using viral load results(≥1000 copies/mL vs<1000 copies/mL)to confirm recency status.For studies with PNS,we evaluated the cascade:Number of partners elicited,successfully contacted,eligible for HIV testing,tested and HIV diagnosis.PNS effectiveness was measured by proportion of new HIV diagnoses from tested partners.Using random effects models,we computed the pooled estimate of recency outcomes and 95%confidence intervals(CIs).RESULTS Twenty-five studies from 17-low-and middle-income countries were included.Of 276315 newly diagnosed people living with HIV,79864 underwent RTRI with an overall pooled recency coverage of 87%(95%CI:67-96).The pooled prevalence of RTRI and RITA recency were 12%(95%CI:9-16)and 7%(95%CI:4-10),respectively.Pooled prevalence of RTRI reclassification was 34%(95%CI:22-49).Of the recent cases who agreed to PNS,253 partners were elicited with an estimated elicitation ratio of 1:1.6.Among partners elicited,99%were successfully contacted,75%were eligible for testing,68%tested for HIV,and 15%were diagnosed with HIV.CONCLUSION High recency testing coverage among newly diagnosed individuals demonstrates the feasibility of monitoring new HIV infections in LMIC.While PNS yielded moderate HIV diagnoses,its targeted approach remains a critical strategy for identifying undiagnosed cases.
基金Project(51979280)supported by the National Natural Science Foundation of ChinaProjects(2016M602972,2018M643852)supported by the Postdoctoral Science Foundation of China。
文摘We have established an elastoplastic analysis model to explore the effect of loading path in an incompressible thin-walled tube under the combined action of axial force and torque based on Mises yield condition and isotropic linear hardening assumption.Further,four stress areas(σx,τx)are divided according to the characteristics of the final stress,and the plastic stress-strain relationship of twelve stress paths in different stress areas is derived.The"primary effect"of the stress path on plastic strain is demonstrated,namely,the plastic strain caused by the pre-loaded stress in path A(tensile stress is initially applied,followed by shear stress)is always greater than that caused by the post-loaded stress in path C(shear stress is initially applied,followed by tensile stress)irrespective of the value of final stress.The"recency effect"of the strain path on the stress is also established,which indicates that the stress caused by the post-loaded strain in path A is always greater than that caused by the pre-loaded strain in path C irrespective of the value of final strain.From the perspective of deformation,the"primary effect"of the stress path on the plastic strain and the"recency effect"of the strain path on the stress are unified.These effects are succinct and universal,and they provide useful insights on the plastic stress-strain relationship under different loading paths.Furthermore,they can serve as a useful reference for optimizing the processing technologies and construction procedures.
基金We would like to greatly appreciate the anonymous reviewers for their insightful comments.This work is supported by The National Key Research and Development Program of China(2016YFB1000302)The National Natural Science Foundation of China(61433019,U1435217).
文摘In the big data era,data unavailability,either temporary or permanent,becomes a normal occurrence on a daily basis.Unlike the permanent data failure,which is fixed through a background job,temporarily unavailable data is recovered on-the-fly to serve the ongoing read request.However,those newly revived data is discarded after serving the request,due to the assumption that data experiencing temporary failures could come back alive later.Such disposal of failure data prevents the sharing of failure information among clients,and leads to many unnecessary data recovery processes,(e.g.caused by either recurring unavailability of a data or multiple data failures in one stripe),thereby straining system performance.To this end,this paper proposes GFCache to cache corrupted data for the dual purposes of failure information sharing and eliminating unnecessary data recovery processes.GFCache employs a greedy caching approach of opportunism to promote not only the failed data,but also sequential failure-likely data in the same stripe.Additionally,GFCache includes a FARC(Failure ARC)catch replacement algorithm,which features a balanced consideration of failure recency,frequency to accommodate data corruption with good hit ratio.The stored data in GFCache is able to support fast read of the normal data access.Furthermore,since GFCache is a generic failure cache,it can be used anywhere erasure coding is deployed with any specific coding schemes and parameters.Evaluations show that GFCache achieves good hit ratio with our sophisticated caching algorithm and manages to significantly boost system performance by reducing unnecessary data recoveries with vulnerable data in the cache.
文摘为了解决传统K-means算法对初始聚类中心敏感和聚类数目事先难以确定的问题,提出了一种改进的K-means算法。改进算法利用最大距离等分策略来选取初始聚类中心,并利用一种评价函数来自动确定聚类数,减少了算法结果对参数的依赖。将改进算法应用到某企业客户分类中时,为提高分类结果的表征性,提出了以客户最近购买时间(Recency)、购买频次(Frequency)、平均购买额(Average Monetary)和购买倾向(Trend)作为客户价值细分变量的RFAT(Recency,frequency,average monetary and trend)模型,对客户RFAT值进行了聚类分析,并提供了针对不同客户群的营销策略。实证研究表明,该文所提出的改进算法和模型可以有效地对企业客户进行分类,能充分反映客户的当前价值和增值潜能。
文摘针对通过零售交易数据进行客户分群时传统方法未考虑商品的价值问题,提出用RFM(recency frequency monetary)表达交易数据的方法,该方法将客户购买的商品和商品类别组成一棵RFM购买树(recency frequency monetary purchase tree,RFMPT).提出基于RFM购买树的快速聚类算法(based recency frequency monetary purchase tree clustering,BRFMPTC),把购买树构建为Cover Tree(CT)索引结构,利用CT结构快速选择k个密度最大的购买树作为中心,将其他对象划分到距它最近的类中心.实验结果表明,在距离加权下,BRFMPTC算法较传统算法在整体上能产生质量更高的聚类结果,性能得到较大提升.
