Binxing Fang

Multisite resource selection and scheduling algorithm on computational grid

Summary form only given. Multisite resource selection and task scheduling is paid more and more attention under the grid environment nowadays with the emergence of high speed WAN. Especially in a distributed computational grid, multisite resource selection and scheduling can significantly reduce the average execution time of grand applications with a limited demand in communication. Therefore we present a CGRS resource selection algorithm based on a new density-based grid resource-clustering algorithm, and implement it in our scalable environment. The analysis and experimental results show the correctness and effectiveness of our resource selection algorithm.

Ontology emergence from folksonomies

The folksonomies built from the large-scale social annotations made by collaborating users are perfect data sources for bootstrapping Semantic Web applications. In this paper, we develop an ontology induction approach to harvest the emergent semantics from the folksonomies. We propose a latent subsumption hierarchy model to uncover the implicit structure of tag space and develop our ontology induction approach on basis of this model. We identify tag subsumptions with a set-theoretical approach and model the tag space as a tag subsumption graph. While turning this graph into a concept hierarchy, we address the problem of inconsistent subsumptions and propose a random walk based tag generality ranking procedure to settle it. We propose an agglomerative hierarchical clustering algorithm utilizing the result of tag generality ranking to generate the concept hierarchy. We conduct experiments on the Delicious dataset. The results of both qualitative and quantitative evaluation demonstrate the effectiveness of the proposed approach.

An efficient anonymous communication protocol for wireless sensor networks

Anonymous communication is very important for many wireless sensor networks, because it can be used to hide the identity of important nodes, such as the base station and a source node. In sensor networks, anonymous communication includes several important aspects, such as source anonymity, communication relationship anonymity, and base station anonymity. Existing sensor network anonymous schemes either cannot achieve all the anonymities or have large computation, storage, and communication overheads. In this paper, we propose an efficient anonymous communication protocol for sensor networks that can achieve all the anonymities while having small overheads on computation, storage, and communication. We compare our anonymous communication protocol with several existing schemes, and the results show that our protocol provides strong anonymity protection and has low overheads. Copyright

Speak the same language with your friends: augmenting tag recommenders with social relations

Many existing tag recommendation approaches ignore the social relations between users. In this paper, we investigate the role of such additional information for the task of personalized tag recommendation. We inject the social relations between users and the content similarities between resources, along with the social annotations made by collaborative users, into a graph representation. To fully explore the structure of this graph, we exploit the methodology of random-walk computation of similarities between all the objects. We develop a personalized collaborative filtering algorithm that combines both the collaborative information and the personalized tag preferences. Experiments on Delicious data demonstrate the effectiveness of the proposed methods.

Towards Efficient Anonymous Communications in Sensor Networks

Anonymous communication is a challenging task in resource constrained wireless sensor networks (WSN). However, anonymity is important for many sensor networks, in which we want to conceal the location and identify of important nodes (such as source nodes and base stations) from attackers. Existing WSN anonymous protocols either cannot achieve complete anonymity, or have large computation and/or storage overheads. In this paper, we present an efficient anonymous communication protocol for sensor networks. Our protocol can achieve sender/source anonymity, communication -relationship anonymity, and the base station anonymity simultaneously, while having small overheads on computation, storage and communication.

Designing robust routing protocols to protect base stations in wireless sensor networks

A base station is the controller and the data-receiving center of a wireless sensor network. Hence, a reliable and secure base station is critical to the network. Once an attacker locates the base station, he or she can do many damages to the network. In this paper, we examine the base station location privacy problem from both the attack and defense sides. First, we present a new attack on base station: parent-based attack scheme PAS. PAS can locate a base station within one radio wireless transmission range of sensors in high-density sensor networks. Different from existing methods, PAS determines the base station location on the basis of parent-child relationship of sensor nodes. Existing base station protection schemes cannot defend against PAS. Second, on the basis of PAS, we propose a two-phase parent-based attack scheme TP-PAS. Our simulation results demonstrate that TP-PAS is able to determine the base station successfully in both low-density and high-density sensor networks. Then, to defend against PAS and TP-PAS, we design a child-based routing protocol and a parent-free routing protocol for sensor networks. Our theory analysis and experiment results show that the parent-free routing protocol has more communication cost and less end-to-end latency compared with the child-based routing protocol. Copyright

A Measurement Study on the Topologies of BitTorrent Networks

BitTorrent (BT) is a widely-used peer-to-peer (P2P) application. Most of BTs characteristics (except the topology) have been studied extensively by measurement approaches. In this paper, we deploy a measurement system to examine some performance-related topology properties of BT. Our goal is to provide a measurement view of the real-world BT topologies and to verify the previous estimations via simulations and real-world experiments. We observe that at the steady stage, a BT topology has short distances and low clustering coefficients, and its degree-frequency exhibits a Gaussian-like distribution. These indicate that a BT network is very close to a random network rather than a scale-free network or a small world. The proportion of peers with large download percentages is very high at the steady stage, showing that the swarm is robust from the resource perspective. We also find out that most high-degree peers have a very fast download speed. However, the low Spearmans rank correlation coefficient indicates that there is no strong correlation between the peer connection degree and the download speed. Different from previous results, we find that the diameter of a BT network at the initial stage is small even when 95% of peers use the peer exchange extension.

A large scale code resolution service network in the Internet of Things.

In the Internet of Things a code resolution service provides a discovery mechanism for a requester to obtain the information resources associated with a particular product code immediately. In large scale application scenarios a code resolution service faces some serious issues involving heterogeneity, big data and data ownership. A code resolution service network is required to address these issues. Firstly, a list of requirements for the network architecture and code resolution services is proposed. Secondly, in order to eliminate code resolution conflicts and code resolution overloads, a code structure is presented to create a uniform namespace for code resolution records. Thirdly, we propose a loosely coupled distributed network consisting of heterogeneous, independent; collaborating code resolution services and a SkipNet based code resolution service named SkipNet-OCRS, which not only inherits DHTs advantages, but also supports administrative control and autonomy. For the external behaviors of SkipNet-OCRS, a novel external behavior mode named QRRA mode is proposed to enhance security and reduce requester complexity. For the internal behaviors of SkipNet-OCRS, an improved query algorithm is proposed to increase query efficiency. It is analyzed that integrating SkipNet-OCRS into our resolution service network can meet our proposed requirements. Finally, simulation experiments verify the excellent performance of SkipNet-OCRS.

Unsupervised Tag Sense Disambiguation in Folksonomies

Disambiguating tag senses can benefit many applications leveraging folksonomies as knowledge sources. In this paper, we propose an unsupervised tag sense disambiguation approach. For a target tag, we model all the annotations involving it with a 3-order tensor to fully explore the multi-type interrelated data. We perform spectral clustering over the hypergraph induced from the 3-order tensor to discover the clusters representing the senses of the target tag. We conduct experiments on a dataset collected from a real-world system. Both the supervised and unsupervised evaluation results demonstrate the effectiveness of the proposed approach.

Checking virtual machine kernel control-flow integrity using a page-level dynamic tracing approach

Kernel control-flow integrity (CFI) of virtual machines is very important to cloud security. VMI-based dynamic tracing and analyzing methods are promising options for checking kernel CFI in cloud. However, the CFI monitors based on tracing always work at instruction or branch level and result in serious virtual machine performance degradation. To meet the performance requirements in the cloud, we present a page-level dynamic VMI-based kernel CFI checking solution. We trace VM kernel execution at page level, which means that the in-page instruction execution cannot trigger our monitor. As a result, the tracing overhead can be greatly reduced. Based on page-level execution information, we propose two policies to describe the kernel control-flow so as to build the secure kernel control-flow database in the learning stage. In the monitoring stage, we compare runtime execution information with the secure database to check kernel CFI. To further reduce the monitoring overhead, we propose two performance optimization strategies. We implement the prototype on Xen and leverage hardware events to trace VM memory page execution. Then, we evaluate the effectiveness and performance of the prototype. The experimental results prove that our system has enough detection capability and the overhead is acceptable.