Jinpeng Huai

EnaCloud: An Energy-Saving Application Live Placement Approach for Cloud Computing Environments

With the increasing prevalence of large scale cloud computing environments, how to place requested applications into available computing servers regarding to energy consumption has become an essential research problem, but existing application placement approaches are still not effective for live applications with dynamic characters. In this paper, we proposed a novel approach named EnaCloud, which enables application live placement dynamically with consideration of energy efficiency in a cloud platform. In EnaCloud, we use a Virtual Machine to encapsulate the application, which supports applications scheduling and live migration to minimize the number of running machines, so as to save energy. Specially, the application placement is abstracted as a bin packing problem, and an energy-aware heuristic algorithm is proposed to get an appropriate solution. In addition, an over-provision approach is presented to deal with the varying resource demands of applications. Our approach has been successfully implemented as useful components and fundamental services in the iVIC platform. Finally, we evaluate our approach by comprehensive experiments based on virtual machine monitor Xen and the results show that it is feasible.

Pseudo Trust: Zero-Knowledge Authentication in Anonymous P2Ps

Most of the current trust models in peer-to-peer (P2P) systems are identity based, which means that in order for one peer to trust another, it needs to know the other peers identity. Hence, there exists an inherent tradeoff between trust and anonymity. To the best of our knowledge, there is currently no P2P protocol that provides complete mutual anonymity as well as authentication and trust management. We propose a zero-knowledge authentication scheme called pseudo trust (PT), where each peer, instead of using its real identity, generates an unforgeable and verifiable pseudonym using a one-way hash function. A novel authentication scheme based on zero-knowledge proof is designed so that peers can be authenticated without leaking any sensitive information. With the help of PT, most existing identity-based trust management schemes become applicable in mutual anonymous P2P systems. We analyze the security and the anonymity in PT, and evaluate its performance using trace-driven simulations and a prototype PT-enabled P2P network. The strengths of our design include (1) no need for a centralized trusted party or CA, (2) high scalability and security, (3) low traffic and cryptography processing overheads, and (4) man-in-middle attack resistance.

ANGEL: Optimal Configuration for High Available Service Composition

With the fast development of Internet and rapid acceptance of Web Service technology, more and more service resources have emerged. Service composition which integrates the functionalities of different services is a promising technique for developing applications across multiple organizations. However, in a distributed, dynamic and autonomous environment, such as a service composition-based system, the availability and reliability are big concerns in terms of nonfunctional properties. In this paper, we propose a novel service composition method, ANGEL, with the target of the improvement of system availability. We adopt redundant mechanism in ANGEL and propose a model to improve the property of the service availability. We model the multiple services selection problem based on redundant mechanism as a nonlinear mixed integer programming problem and therefore, we propose two heuristic algorithms to select multiple feasible services that have the same functions, but with better availability. In order to maintain the availability of composite services, we further introduce monitor and detection mechanisms. Through the comprehensive experiments, we find that our proposed techniques can indeed achieve better availability as expected.

Ad-UDDI: an active and distributed service registry

In SOA (Service Oriented Architecture), web service providers use service registries to publish services and requestors use registries to find them. The major current service registry specifications, UDDI (Universal Description, Discovery and Integration), has the following drawbacks. First, it replicates all public service publications in all UBR (Universal Business Registry) nodes, which is not scalable and efficient, and second, it collects service information in a passive manner, which means it waits for service publication, updating or discovery request passively and thus cannot guarantee the real-time validity of the services information. In this paper, we propose an active and distributed UDDI architecture called Ad-UDDI, which extends and organizes the private or semi-private UDDIs based on industry classifications. Further, Ad-UDDI adopts an active monitoring mechanism, so that service information can be updated automatically and the service requestors may find the latest service information conveniently. We evaluate Ad-UDDI by comprehensive simulations and experimental results show that it outperforms existing approaches significantly.

Enhancing reliability to boost the throughput over screen-camera links

With the rapid proliferation of camera-equipped smart devices (e.g., smartphones, pads, tablets), visible light communication (VLC) over screen-camera links emerges as a novel form of near-field communication. Such communication via smart devices is highly competitive for its user-friendliness, security, and infrastructure-less (i.e., no dependency on WiFi or cellular infrastructure). However, existing approaches mostly focus on improving the transmission speed and ignore the transmission reliability. Considering the interplay between the transmission speed and reliability towards effective end-to-end communication, in this paper, we aim to boost the throughput over screen-camera links by enhancing the transmission reliability. To this end, we propose RDCode, a robust dynamic barcode which enables a novel packet-frame-block structure. Based on the layered structure, we design different error correction schemes at three levels: intra-blocks, inter-blocks and inter-frames, in order to verify and recover the lost blocks and frames. Finally, we implement RDCode and experimentally show that RDCode reaches a high level of transmission reliability (e.g., reducing the error rate to 10%) and yields a at least doubled transmission rate, compared with the existing state-of-the-art approach COBRA.

Distributed graph pattern matching

Graph simulation has been adopted for pattern matching to reduce the complexity and capture the need of novel applications. With the rapid development of the Web and social networks, data is typically distributed over multiple machines. Hence a natural question raised is how to evaluate graph simulation on distributed data. To our knowledge, no such distributed algorithms are in place yet. This paper settles this question by providing evaluation algorithms and optimizations for graph simulation in a distributed setting. (1) We study the impacts of components and data locality on the evaluation of graph simulation. (2) We give an analysis of a large class of distributed algorithms, captured by a message-passing model, for graph simulation. We also identify three complexity measures: visit times, makespan and data shipment, for analyzing the distributed algorithms, and show that these measures are essentially controversial with each other. (3) We propose distributed algorithms and optimization techniques that exploit the properties of graph simulation and the analyses of distributed algorithms. (4) We experimentally verify the effectiveness and efficiency of these algorithms, using both real-life and synthetic data.

HyperMIP: Hypervisor Controlled Mobile IP for Virtual Machine Live Migration across Networks

Live migration provides transparent load-balancing and fault-tolerant mechanism for applications. When a Virtual Machine migrates among hosts residing in two networks, the network attachment point of the Virtual Machine is also changed, thus the Virtual Machine will suffer from IP mobility problem after migration. This paper proposes an approach called Hypervisor controlled Mobile IP to support live migration of Virtual Machine across networks, which enables virtual machine live migration over distributed computing resources. Since Hypervisor is capable of predicting exact time and destination host of Virtual Machine migration, our approach not only can improve migration performance but also reduce the network restoration latency. Some comprehensive experiments have been conducted and the results show that the HyperMIP brings negligible overhead to network performance of Virtual Machines. The network restoration time of HyperMIP supported migration is about only 3 second. HyperMIP is a promising essential component to provide reliability and fault tolerant for network application running in Virtual Machine.

Strong simulation: Capturing topology in graph pattern matching

Graph pattern matching is finding all matches in a data graph for a given pattern graph and is often defined in terms of subgraph isomorphism, an NP-complete problem. To lower its complexity, various extensions of graph simulation have been considered instead. These extensions allow graph pattern matching to be conducted in cubic time. However, they fall short of capturing the topology of data graphs, that is, graphs may have a structure drastically different from pattern graphs they match, and the matches found are often too large to understand and analyze. To rectify these problems, this article proposes a notion of strong simulation, a revision of graph simulation for graph pattern matching. (1) We identify a set of criteria for preserving the topology of graphs matched. We show that strong simulation preserves the topology of data graphs and finds a bounded number of matches. (2) We show that strong simulation retains the same complexity as earlier extensions of graph simulation by providing a cubic-time algorithm for computing strong simulation. (3) We present the locality property of strong simulation which allows us to develop an effective distributed algorithm to conduct graph pattern matching on distributed graphs. (4) We experimentally verify the effectiveness and efficiency of these algorithms using both real-life and synthetic data.

An Adaptive Web Services Selection Method Based on the QoS Prediction Mechanism

In recent years, many QoS-based web service selection methods have been proposed. However, as QoS changes dynamically, the atomic services of a composite web service could be replaced with other ones that have better quality. The performance of a composite web service will be decreased if this replacement happens frequently in runtime. Predicting the change of QoS accurately in select phase can effectively reduce this web services “thrash”. In this paper, we propose a web service selection algorithm GFS (Goodness-Fit Selection algorithm) based on QoS prediction mechanism in dynamic environments. We use structural equation to model the QoS measurement of web services. By taking the advantage of the prediction mechanism of structural equation model, we can quantitatively predict the change of quality of service dynamically. Optimal web service is selected based on the predicted results. Simulation results show that in dynamic environments, GFS provides higher selection accuracy than previous selection methods.

A Probabilistic Approach for Web Service Discovery

Web service discovery is a vital problem in service computing with the increasing number of services. Existing service discovery approaches merely focus on WSDL-based keyword search, semantic matching based on domain knowledge or ontologies, or QoS-based recommendations. The keyword search omits the underlying correlations and semantic knowledge or QoS information is not always available. In this paper, we propose a probabilistic service discovery approach to help web service users to retrieve related services and to improve the search performance. Specifically, we apply a probabilistic model to characterize the latten topics between services and queries, and then propose a matching method based on the topic relevance. Experiments on services from a real service repository confirm the feasibility and efficiency of this proposed method.