一种高效的合作实时事务并行检验点算法

许多数据和活动上都有很强时间性的应用在地理上同时具有分布性,这种应用需求使得分布式实时数据库的研完成为数据库研究领域的热点。在实时事务执行时,事务故障或数据竞争会导致事务重启,为了减少因重启而损失的工作量,可以采用检验点技术以利于事务时间正确性的满足。在一些分布式实时数据库应用中,不同结点的事务通过消息交换形成合作关系,当某一事务记检验点时,为保证合作事务间的全局一致性,相关事务也要相应地记检验点。传统的协同检验点方法没有考虑应用的定时约束,不能很好地支持分布式实时事务处理。本文提出了一种高效的并行协同检验点方法,该算法既具有最小协同检验点特性又使全局检验点过程延时最小。实验表明该算法减少了全局检验点阻塞时间,有利于分布式实时事务截止期的满足。     

分布式系统中断点释放算法

本文讨论了在分布式系统中，以进程通讯关系设置断点和回卷原则，提出了一种断点释放算法－断点最小集合算法，以定时地对断点拷贝整理，并给出了该算法的复杂度。由该算法所得到的断点最小集合能够保证系统中无论哪个节点机发生故障，都能使它们回到一致性状态。     

面向OpenMP的混合检查点机制

检查点/续算是软件容错的重要途径之一。论文描述了一个系统级和应用级混合的OpenMP检查点机制,系统级支持不仅使检查点系统具有了好的透明性,并且使共享数据的保存不再由主线程单独完成,具有良好的数据局部性。应用级OpenMP协议将与OpenMP相关的协议处理独立出来,提高了系统的可移植性。NPB3.2-OMP测试结果表明,检查点和续算所需要的时间开销小,能够满足大规模程序的实际需求。     

并行可视化调试工具中检查点使能的研究与实现

与串行程序相比,并行程序调试会遇到新的问题。首先并行程序往往需要长时间运行,从而导致并行程序调试是一个尤其费时的过程;其次并行程序调试过程中,某一次调试出现的错误在下次调试的时候不一定出现,给错误跟踪带来了很大困难。本文针对这两个问题,设计和实现了一个中间件系统,在并行调试工具XMPI中使能BLCR检查点系统的。通过该中间件,在使用XMPI调试大型MPI并行程序的时候,减少调试阶段并行程序运行时间,并且可以更好跟踪并行程序错误,提高并行程序开发效率。     

基于作业进展描述的计算网格作业检查点

分析了计算网格环境中实现检查点机制的特殊性,提出了一种新的应用级检查点方法：基于作业进展描述的检查点方法。介绍了这种检查点方法的基本思想,定义了构成作业进展描述的作业进展状态对象和作业进展描述对象,这些对象的方法构成了检查点API;讨论了检查点作业的构建。     

向后滚动检查点技术在虚存中的应用

本文介绍了容错重复恢复技术中的向后滚动检查点算法，并针对减少系统开销的问题，提出了在虚拟存贮器中的一种实现方案。     

On-the-fly, incremental, consistent reading of entire databases

We describe an algorithm to read entire databases with locking concurrency control allowing multiple readersor an exclusive writer. The algorithm runs concurrently with the normal transaction processing (on-the-fly), and locks the entities in the database one by one (incremental). We prove that the algorithm produces consistent pictures of the database. We also show that conflicts between the algorithm and some updates, although necessary, can be resolved.Reading entire databases consistently, on-the-fly, incremental algorithms can avoid the database downtime trade-off between frequent checkpoints and crash recovery delay, thus improving system availability and reliability. Our algorithm reads the database once and writes only to sequential output, lowering its implementation and execution costs. A simple extension runs in parallel on several processors and produces consistent pictures of entire distributed databases.This work was partially supported by the National Science Foundation under Grant No. MCS-8004111.     

构件化软件内建自测试技术研究

目前,构件技术已经在软件工程中广泛使用,同时给软件测试带来了一系列问题.借用硬件自测试的思路,提出了在构件中设置测试点、插装构件接口探针等方法,实现了构件化软件内建自测试.     

New Frontiers about the Role of Human Microbiota in Immunotherapy: The Immune Checkpoint Inhibitors and CAR T-Cell Therapy Era

Microbiota is considered an independent organ with the capability to modulate tumor growth and response to therapies. In the chemo-free era, the use of new immunotherapies, more selective and effective and less toxic, led to the extension of overall survival of patients, subject to their ability to not stop treatment. This has focused scientists’ attention to optimize responses by understanding and changing microbiota composition. While we have obtained abundant data from studies in oncologic and hematologic patients receiving conventional chemotherapy, we have less data about alterations in intestinal flora in those undergoing immunotherapy, especially based on Chimeric Antigen Receptor (CAR) T-cells. Actually, we know that the efficacy of Programmed Cell Death 1 (PD-1), PD-1 ligand, and Cytotoxic T lymphocyte-associated protein 4 (CTLA-4) is improved by probiotics rich in Bifidobacterium spp., while compounds of Bacteroidales and Burkholderiales protect from the development of the anti-CTLA-4-induced colitis in mouse models. CAR T-cell therapy seems to not be interfering with microbiota; however, the numerous previous therapies may have caused permanent damage, thus obscuring the data we might have obtained. Therefore, this review opens a new chapter to transfer known acquisitions to a typology of patients destined to grow.