A general distributed scalable grid scheduler for independent tasks

We consider non-preemptively scheduling a bag of independent mixed tasks (hard, firm and soft) in computational grids. Based upon task type, we construct a novel generalized distributed scheduler (GDS) for scheduling tasks with different priorities and deadlines. GDS is scalable and does not require knowledge of the global state of the system. It is composed of several phases: a multiple attribute ranking phase, a shuffling phase, and a task-resource matched peer to peer dispatching phase. Results of exhaustive simulation demonstrate that with respect to the number of high-priority tasks meeting deadlines, GDS outperforms existing approaches by 10%–25% without degrading schedulability of other tasks. Indeed, with respect to the total number of schedulable tasks meeting deadlines, GDS is slightly better. Thus, GDS not only maximizes the number of mission-critical tasks meeting deadlines, but it does so without degrading the overall performance. The results have been further confirmed by examining each component phase of GDS. Given that fully known global information is time intensive to obtain, the performance of GDS is significant. GDS is highly scalable both in terms of processors and number of tasks—indeed it provides superior performance over existing algorithms as the number of tasks increase. Also, GDS incorporates a shuffle phase that moves hard tasks ahead improving their temporal fault tolerance. Furthermore, since GDS can handle mixed task types, it paves the way to open the grid to make it amenable for commercialization. The complexity of GDS is O(n²m)$O\left(n^{2}m\right)$ where n$n$ is the number of tasks and m$m$ the number of machines.     

面向异构DHT存储的数据与位置解耦算法

分布式哈希表(distributed hash table, DHT)由于其高效的数据寻址方式而被广泛应用于分布式存储.传统DHT必须将数据存放在指定节点中才能实现高效的数据分布式寻址,极大地限制了DHT技术的应用范围.例如,在异构存储网络中,节点的存储空间、带宽、稳定性等均有较大差异,结合数据特征和节点性能差异选择合适的数据存放节点可以很大程度上提高数据的访问效率,而传统DHT数据和存储位置紧耦合的特征导致其难以应用于异构的存储网络中.针对此问题,提出了vRoute算法以实现DHT中数据标识与其存储位置的解耦.通过构建基于Bloom Filter的分布式数据索引, vRoute算法可以在不降低数据寻址效率的基础上允许数据存储在网络中的任意节点.通过扩展Kademlia算法实现了vRoute,并从理论上证明了vRoute算法的有有效性.最后,模拟实验表明vRoute以较低的存储、网络开销实现了和传统的DHT算法接近的数据寻址效率.     

面向连接的P2P即时通信中继策略研究

P2P即时通信模型要求所有对等节点都能进行双向通信,但网络安全技术方案的实施,使得整个P2P通信域有了内网和外网的区分,并且外网节点不能向内网主动发起连接,故P2P双向心通信受到限制。本文分析并设计了一种高效的通信机制-小服务器节点(Small Service Peer)避免由第三方的通信中继服务所导致的延时。提出了内网中继判定算法,以优化处于同一内网节点之间通信的性能。试验表明,采用本文提出小服务器对等节点的通信机制和内网中继判定算法,在不改变下层网络结构和配置的条件下,可以显著降低P2P应用系统对中继服务器的依赖,并提高即时通信系统实时性。     

连锁业务中远程数据传输的实现

为了展示连锁业务中远程数据传输的实现，以GSP管理软件中的总店和连锁分店之间的数据传输为例，讨论了连锁销售模式的企业如何选择合适的组网方式，在速度、成本、容错这3个方面都能够达到最佳。重点论述了在．NET实现远程数据传输的关键技术和具体实现方法，实践证明文中提出的方法是有效的。     

The reliability of ethical reviews: Is it desirable?

Comments on the article, "Reliability in ethics reviews: Some initial empirical findings," by W. O. Eaton (see record 1983-33453-001). The present author explores the possibility that acceptance of low reliability in ethical reviews may not reflect complacency, but rather might reflect an assessment of the situation which is to be desired rather than avoided. The point that is worth considering is that very high levels of agreement in ethical judgements may not be desirable; indeed, he suggests that high levels of agreement in such reviews might reflect an inadequate sampling of views. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

基于Windows95的实时监控软件通讯任务的设计

越来越多的实时监控软件采用Ｗｉｎｄｏｗｓ９５ 这其平台。基于对等通讯的思想,本文讨论Ｗｉｎｄｏｗ ｓ９５ 下的两种比较特殊的通讯方式：直接操作网卡硬件的网络能讯方式和基于ＮｅｔＢＩＯＳ的网络通讯方式     

短消息平台的原理与设计

结合作者的实际工作经验，介绍了移动短消息的收发原理和短消息平台的体系结构、设计方法，并以本文作者负责组建的青岛短消息平台为例，介绍了其中的系统分析、系统设计、体系结构和功能构成等关键技术问题．     

Virtual peers as partners in storytelling and literacy learning

Abstract   Literacy learning — learning how to read and write — begins long before children enter school. One of the key skills to reading and writing is the ability to represent thoughts symbolically and share them in language with an audience who may not necessarily share the same temporal and spatial context. Children learn and practice these important language skills everyday, telling stories with the peers and adults around them. In particular, storytelling in the context of peer collaboration provides a key environment for children to learn language skills important for literacy. In light of this, an embodied conversational agent, Sam , who tells stories collaboratively with children was designed. Sam looks like a peer for pre-school children, but tells stories in a developmentally advanced way, modelling narrative skills important for literacy. Results demonstrated that children who played with the virtual peer told stories that more closely resembled the virtual peer's linguistically advanced stories: using more quoted speech and temporal and spatial expressions. In addition, children listened to Sam's stories carefully, assisting her and suggesting improvements. The potential benefits of having technology play a social role in young children's literacy learning is discussed.