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GFCache: A Greedy Failure Cache Considering Failure Recency and Failure Frequency for an Erasure-Coded Storage System
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作者 Mingzhu Deng Fang Liu +2 位作者 Ming Zhao zhiguang chen Nong Xiao 《Computers, Materials & Continua》 SCIE EI 2019年第1期153-167,共15页
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
关键词 FAILURE CACHE GREEDY recovery ERASURE coding FAILURE RECENCY FAILURE frequency
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政策执行研究50年:理论形成与体系构建 被引量:1
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作者 刘征 陈志光 李兵 《中国公共政策评论》 2024年第1期1-16,共16页
政策执行是公共政策周期中必不可少的环节,从根本上决定着政策能否成功,以及政策解决问题或实现目标的程度和范围。自1973年政策执行正式成为政策研究者的关注焦点以来,到2023年已整整50年。半个世纪里,政策执行理论逐渐丰富完善,研究... 政策执行是公共政策周期中必不可少的环节,从根本上决定着政策能否成功,以及政策解决问题或实现目标的程度和范围。自1973年政策执行正式成为政策研究者的关注焦点以来,到2023年已整整50年。半个世纪里,政策执行理论逐渐丰富完善,研究范式不断发展演进,研究者们从各个维度不断探寻影响政策执行的关键变量和重要条件。本文通过对政策执行研究范式的梳理,以及对当前,即第四代执行理论重点内容的分析,归纳出影响政策执行的六类关键变量,并提出未来开展政策执行研究需要关注的一些重要方面。本文认为,应推动执行学成为一门独立学科,为考察、预判和解决政策执行中的各种问题提供更加科学全面的视角与方法。 展开更多
关键词 政策执行 范式演进 关键变量 体系构建
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A meta-analysis of randomized trials of maintenance bacillus Calmette-Guerin instillation efficacy against recurrence of T1G3 bladder tumor
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作者 Jiangang PAN Xing ZHOU +1 位作者 Ruifa HAN zhiguang chen 《Frontiers of Medicine》 SCIE CSCD 2008年第3期259-263,共5页
Meta-analysis was used to determine whether maintenance intravesical bacillus Calmette-Guerin(BCG)could reduce recurrence after transurethral resection of tumor 1 grade 3(T1G3)superficial bladder cancer.All available ... Meta-analysis was used to determine whether maintenance intravesical bacillus Calmette-Guerin(BCG)could reduce recurrence after transurethral resection of tumor 1 grade 3(T1G3)superficial bladder cancer.All available published data of randomized clinical trials comparing transurethral resection plus intravesical BCG to either resection alone or resection plus another treat-ment on the treatment results in patients with superficial bladder cancer of T1G3 were selected for analysis.Both the fixed effects model and random effects model were applied,and the odds ratio(OR)with its 95%confidence interval(CI)was used as the effect size estimate.Sensitivity analysis and publication bias determination were performed by funnel plots and comparing ORs of different models.Within the follow-up period,375 of 915(41.0%)BCG-treated patients and 332 of 733(45.3%)non-BCG-treated patients developed tumor recurrence.In the combined results,a statistically signifi-cant difference in the ORs for tumor recurrence between the two treatment groups was found(randomized model combined effect OR 0.58,95%CI 0.41 to 0.83,P 50.003).The stratified meta-analysis did not show any statistically significant confounding effects on the results when strati-fied by BCG strains.The randomized model combined effect OR of Pasteur F and other strains were 0.50(95%CI 0.26 to 0.95,P 50.04)and 0.63(95%CI 0.40 to 0.99,P 50.04),respectively.Therefore,we came to the conclu-sion that adjuvant maintenance instillation BCG com-bined with transurethral resection of bladder tumor(TURBT)is an effective conservative treatment for pre-venting recurrence of T1G3 bladder cancer. 展开更多
关键词 urinary bladder neoplasms tumor 1 grade 3 RECURRENCE odds ratio META-ANALYSIS
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