A grid-based node split algorithm for managing current location data of moving objects

There is rapidly increasing interest in Location Based Service (LBS) which utilizes location data of moving objects. To efficiently manage the huge amounts of location data in LBS, the GALIS (Gracefully Aging Location Information System) architecture, a cluster-based distributed computing architecture, is proposed. The GALIS using the non-uniform 2-level grid algorithm performs load balancing and indexing for nodes. However, the non-uniform 2-level grid algorithm has a problem creating unnecessary nodes when moving objects are crowded in a certain region. Therefore, a new node split algorithm, which is more efficient for various distribution of moving objects, is proposed in this paper. Because the algorithm proposed in this paper considers spatial distribution for the current location of moving objects, it can perform efficient load balancing without creating unnecessary nodes even when moving objects are congested in a certain region. Besides, the various data distribution configuration for moving objects has been experimented by implementing node split simulators and it’s been verified that the proposed algorithm can split nodes more efficiently than the existing algorithm.

Web集群服务器可用性的提高

以Web集群服务器的后端节点作为研究对象,通过减少后端节点的MTTR（Mean Timeto Repair）,来提高它们的可用性,从而提高整个集群服务器的可用性。首先,通过分析现有的故障恢复方案的不足,提出了新的改进方案,在新的方案中,采用了动态地检测和发送状态信息的策略。并引入了故障猜测状态,弥补了现有方案的不足。最后设计了一个试验环境,与现有的方案测试相比,使用改进的方案,MTTR（平均敞障修复时间）减少了63％,很好地提高了后端节点的可用性。     

An efficient prototype merging strategy for the condensed 1-NN rule through class-conditional hierarchical clustering

A generalized prototype-based classification scheme founded on hierarchical clustering is proposed. The basic idea is to obtain a condensed 1-NN classification rule by merging the two same-class nearest clusters, provided that the set of cluster representatives correctly classifies all the original points. Apart from the quality of the obtained sets and its flexibility which comes from the fact that different intercluster measures and criteria can be used, the proposed scheme includes a very efficient four-stage procedure which conveniently exploits geometric cluster properties to decide about each possible merge. Empirical results demonstrate the merits of the proposed algorithm taking into account the size of the condensed sets of prototypes, the accuracy of the corresponding condensed 1-NN classification rule and the computing time.     

Secure communications for cluster-based ad hoc networks using node identities

Ad hoc networks are self-configurable networks with dynamic topologies. All involved nodes in the network share the responsibility for routing, access, and communications. The mobile ad hoc network can be considered as a short-lived collection of mobile nodes communicating with each other. Such networks are more vulnerable to security threats than traditional wireless networks because of the absence of the fixed infrastructure. For providing secure communications in such networks, lots of mechanisms have been proposed since the early 1990s, which also have to deal with the limitations of the mobile ad hoc networks, including high power saving and low bandwidth. Besides, public key infrastructure (PKI) is a well-known method for providing confidential communications in mobile ad hoc networks. In 2004, Varadharajan et al. proposed a secure communication scheme for cluster-based ad hoc networks based on PKI. Since the computation overheads of the PKI cryptosystem are heavy for each involved communicating node in the cluster, we propose an ID-based version for providing secure communications in ad hoc networks. Without adopting PKI cryptosystems, computation overheads of involved nodes in our scheme can be reduced by 25% at least.     

Reliability analysis of cluster-based ad-hoc networks

The mobile ad-hoc wireless network (MAWN) is a new and emerging network scheme that is being employed in a variety of applications. The MAWN varies from traditional networks because it is a self-forming and dynamic network. The MAWN is free of infrastructure and, as such, only the mobile nodes comprise the network. Pairs of nodes communicate either directly or through other nodes. To do so, each node acts, in turn, as a source, destination, and relay of messages. The virtue of a MAWN is the flexibility this provides; however, the challenge for reliability analyses is also brought about by this unique feature. The variability and volatility of the MAWN configuration makes typical reliability methods (e.g. reliability block diagram) inappropriate because no single structure or configuration represents all manifestations of a MAWN. For this reason, new methods are being developed to analyze the reliability of this new networking technology. New published methods adapt to this feature by treating the configuration probabilistically or by inclusion of embedded mobility models. This paper joins both methods together and expands upon these works by modifying the problem formulation to address the reliability analysis of a cluster-based MAWN. The cluster-based MAWN is deployed in applications with constraints on networking resources such as bandwidth and energy. This paper presents the problem's formulation, a discussion of applicable reliability metrics for the MAWN, and illustration of a Monte Carlo simulation method through the analysis of several example networks.     

基于co-occurrence相似度的聚类集成方法

首先提出了一种基于属性值的co-occurrence相似度概念,通过对其进一步的研究,提出了3个等价性表述;然后对属性值之间的co-occurrence相似度进行引申,给出了数据对象之间co-occurrence相似度的定义,并将其成功应用到聚类集成方法中。利用co-occurrence相似度在计算某个初始聚类结果中数据对象之间的相似度时,充分考虑了其他初始聚类结果和该初始聚类结果之间的相互影响和联系。实验表明, 基于co-occurrence相似度的聚类集成（CSCE）方法能有效识别数据之间的细微结构,有助于提高聚类集成的效果。     

An integrated,programming model-driven framework for NoC–QoS support in cluster-based embedded many-cores

Embedded SoC designs are embracing the many-core paradigm to deliver the required performance to run an ever-increasing number of applications in parallel. Networks-on-Chip (NoC) are considered as a convenient technology to implement many-core embedded platforms. The complex and non-uniform nature of the traffic flows generated when multiple parallel applications are running simultaneously calls for Quality-of-Service (QoS) extensions in the NoC, but to efficiently exploit similar services it is necessary to expose them to the software in a easy-to-use yet efficient manner. In this paper we present an integrated hardware/software approach for delivering QoS on top of an hybrid OpenMP-MPI parallel programming model. Our experimental results show the effectiveness of our proposal over a broad range of benchmarks and application mappings, demonstrating the ability to manage parallelism under QoS requirements effortlessly from the programming model.     

基于Cluster的数据网格请求代理服务器设计*

数据网格为数据密集型的应用提供了强有力的支持,数据服务是数据网格的核心,因而数据请求代理(DRB)服务器的设计是实现数据服务的关键。一个结构、性能较好的服务器能屏蔽数据的广域分布性和异构性,实现一体化数据访问、存储、传输与管理。基于Cluster实现了一种数据请求代理服务器,这种服务器实现了上述目标,并具有许多优点,特别在具有多Cluster的高性能计算中,可以同时建立多个连接进行数据分块传输,能够获得Cluster-to-Cluster 的聚集吞吐率。介绍了基于Cluster的DRB详细设计方案,描述了     

基于侧信道与量化推理缺陷的模型逆向攻击

模型逆向攻击旨在恢复部署在推理终端的神经网络模型的结构和权重值,是AI安全中的基础问题,为对抗样本等高阶攻击提供数据支撑.提出了一种名为Cluster-based SCA的新型模型权重逆向方法,该方法不要求攻击者构造泄露模型.Cluster-based SCA方法以量化推理中存在的安全隐患为出发点,深入分析了量化推理过...