Yuanzhuo Wang

Significance and Challenges of Big Data Research

In recent years, the rapid development of Internet, Internet of Things, and Cloud Computing have led to the explosive growth of data in almost every industry and business area. Big data has rapidly developed into a hot topic that attracts extensive attention from academia, industry, and governments around the world. In this position paper, we first briefly introduce the concept of big data, including its definition, features, and value. We then identify from different perspectives the significance and opportunities that big data brings to us. Next, we present representative big data initiatives all over the world. We describe the grand challenges (namely, data complexity, computational complexity, and system complexity), as well as possible solutions to address these challenges. Finally, we conclude the paper by presenting several suggestions on carrying out big data projects.

Stochastic game net and applications in security analysis for enterprise network

Stochastic game theoretic framework has been used in many fields of networks with interactive behaviors. However, further use of this framework is limited due to the following reasons. Firstly, it is difficult to build comprehensive and rigorous models for complex network structures by the state-based game model. Secondly, solving and extending the dynamic behaviors of participators of the network are nearly impossible, because of the complexity of state transitions. Last but not least, general game model is not able to describe and analyze specific events and behaviors in some kinds of networks, like enterprise networks. In this paper, we propose a new modeling paradigm (stochastic game net, or SGN) for stochastic games representation with Petri nets. Based on our graphical tool, stochastic game problems can be described clearly, and the model can be solved and extended easily. Moreover, this paper puts forth a series of methods for modeling and analyzing the competitive game by SGN, which is the main contribution of this work. Our achievements are applied to the security analysis for enterprise networks. The analysis results prove the powerful ability of our achievements in solving the complicated and dynamic game problems. Furthermore, our approaches can be used to calculate the existence and the value of an equilibrium point.

QoS-aware Composite Service Selection in Grids

Grid computing powered by Web service technology is creating abundant service-oriented applications which are promoting the sharing and collaboration of global resources. Complex tasks can be fulfilled quickly and efficiently by combining (physically distributed) individual services into a competent composite service. Since a lot of available individual services have the same functional properties while different non-functional properties (e.g. quality of service), decisions have to be made to select superior individual services from candidates for service composition. In this paper, the authors present a quality of service (QoS) model of service composition, as well as a composite service selection approach which can optimally choose the competent services, in the sense of satisfying users QoS requirement, for the demanded composite services with specified composite structures

Modeling and security analysis of enterprise network using attack–defense stochastic game Petri nets

In this paper, we propose a novel modeling method attack–defense stochastic game Petri nets (or ADSGN) to model and analyze the security issues in enterprise network. We firstly give the definition and modeling method algorithm of ADSGN and then propose the algorithm of the strategy. The proposed ADSGN method is successfully applied to describe the attack and defense courses in the enterprise network. Finally, we analyze the mean time to first security breach and the mean time to security breach in the enterprise network quantifiably, and proved that our method can also be applied to other areas with respect to game issues. Copyright

Security Analysis of Enterprise Network Based on Stochastic Game Nets Model

In this paper, we propose a novel modeling method, Stochastic Game Nets (SGN), and use it to model and analyze the security issues in enterprise networks. Firstly, the definition and modeling algorithm of Stochastic Game Nets are given. And then we apply the Stochastic Game Nets method to describe the attack and defense course in the enterprise networks successfully, and find a Nash equilibrium. Finally we analyze the confidentiality and integrity of the enterprise network quantificationally based on the model. The method can also be applied to other areas with respect to a game.

Modeling and survivability analysis of service composition using Stochastic Petri Nets

In this paper, we propose a service composition model method that supports quantitative computation based on Stochastic Petri Nets (SPN). It can capture the semantics of complex service combinations and their respective specifications. In this method, services are divided into interior services and exterior services. The exterior services will be published to the users, while the interior ones do not need to be published. Six equivalent simplified theorems which can be used to simplify the complex models of interior services to simple models of exterior services are presented. They enable the minimization of the state space of the model and make quantitative computation feasible. In addition, since Grid services are always affected by all kinds of churns in actual applications, we also research survivability and its main attributes for Grid service composition. The definition and computational methods based on the model are put forward. In the end, we use the method presented above to describe and analyze an example of travel Grid services successfully.

Prevent DNS Cache Poisoning Using Security Proxy

DNS has been suffering from cache poisoning attack for a long time. The attacker sends camouflaged DNS response to trick the domain name server, and inserts malicious resource record into the cached database. Because the original DNS protocol only depends on 16-bit transaction ID to verify the response packet, it is prone to be guessed by the attacker. Although many strategies such as transaction randomizing, source port randomizing and the 0x20 technique have been applied to improve the resistance of DNS, the attacker still has chance to poison DNS server in an acceptable time. Other more complicated strategy such as DNSSEC which provides stricter prevention mechanism is not easy to deploy and is not widely adopted yet. To address the problem, we present a novel strategy called Security Proxy. The architecture can be easily implemented and deployed on existing DNS server without modification of DNS server itself. The embedded two schemes Selective Re-Query and Security Label Communication can cooperate and effectively prevent the cache poisoning attack. We analyze our strategy from both the capability and efficiency. Then we find that our Security Proxy has obvious advantage over the original transaction ID, the source port randomizing and 0x20 techniques.

Security Analysis for Online Banking System Using Hierarchical Stochastic Game Nets Model

In this paper, we propose hierarchical Stochastic Game Nets, and use it to model and analyze the security issues in online banking system. Firstly, the definition and modeling algorithm of hierarchical Stochastic Game Nets are given. In which, some theorems are proved. Then we apply hierarchical Stochastic Game Nets to describe the attack and defense course in the online banking. Finally we analyze the attack time and attack probability in the online banking quantitatively based on the model successfully.

Improving the Convergence and Stability of Congestion Control Algorithm

The traditional TCP congestion control is inefficient for high speed networks and it is a challenge to design a high speed replacement for TCP. By simulating some existing high speed protocols, we find that these high speed protocols have limitations in convergence and stability. To address these problems, we apply a population ecology model to design a novel congestion control algorithm-Coupling Logistic TCP(CLTCP). It is based on bandwidth pre-assignment that is similar to XCP and MaxNet. The pre-assignment rate factor is computed in the routers based on the information of the router capacity, the aggregate incoming traffic and the queue length. Then the senders adjust the sending rate according to the pre-assignment rate factor which carries by the packet to strengthen the convergence and stability of transport protocol. The theoretical analysis and simulation results show that CLTCP provides not only fast convergence and strong stability, but also high utilization and fair bandwidth allocation regardless of round trip time.

Extended HMM and Ranking Models for Chinese Spelling Correction

Spelling correction has been studied for many decades, which can be classified into two categories: (1) regular text spelling correction, (2) query spelling correction. Although the two tasks share many common techniques, they have different concerns. This paper presents our work on the CLP-2014 bake-off. The task focuses on spelling checking on foreigner Chinese essays. Compared to online search query spelling checking task, more complicated techniques can be applied for better performance. Therefore, we proposed a unified framework for Chinese essays spelling correction based on extended HMM and ranker-based models, together with a rule-based model for further polishing. Our system showed better performance on the test dataset.