14354537
Server scheduling scheme for asynchronous cluster video server
In this paper, we propose an asynchronous cluster video server architecture, which is quite different from the synchronous video server architecture in various aspects such as striping policy, placement policy, and server scheduling algorithm. This architecture has the benefits that the system scales unlimitedly with the number of disks and videos. We discuss the main design issues and compute the buffer requirement at both client side and server side, scheduling delay, and prefill delay. The result is exciting compared with the synchronous server scheduling algorithm. It requires fewer client buffers and server buffers, consumes less system response time and can be scalable. To improve system performance, group sweeping scheduling (GSS) is applied.
21826244
Fault-tolerant grid architecture and practice
Grid computing emerges as effective technologies to couple geographically distributed resources and solve large-scale computational problems in wide area networks. The fault tolerance is a significant and complex issue in grid computing systems. Various techniques have been investigated to detect and correct faults in distributed computing systems. Unreliable fault detection is one of the most effective techniques. Globus as a grid middleware manages resources in a wide area network. The Globus fault detection service uses the well-known techniques based on unreliable fault detectors to detect and report component failures. However, more powerful techniques are required to detect and correct both system-level and application-level faults in a grid system, and a convenient toolkit is also needed to maintain the consistency in the grid. A fault-tolerant grid platform (FTGP) based on an unreliable fault detector and the Globus fault detection service is presented in this paper. The platform offers effective strategies in such three aspects as grid key components, user tasks, and high-level applications.
2985442
Analysis of large-scale topological properties for peer-to-peer networks
In This work we present a thorough study of the topological properties of the Gnutella network, which provides insight into the nature of the underlying system, helps us design high performance algorithms and generates more realistic topologies for simulation experiments. We compare two theoretical models of growing networks with the present real data of the Gnutella network.
8142897
Efficient Immunization Algorithm for Peer-to-Peer Networks
In this paper, we present a detail study about the immunization of viruses in Peer-to-Peer networks exhibiting power-law degree distributions By comparing two different immunization strategies (randomized and degree-based), we conclude that it is efficient to immunize the highly connected nodes in order to eradicate viruses from the network Furthermore, we propose an efficient updating algorithm for global virus database according to the degree-based immunization strategy.
20093601
Efficient Immunization Algorithm for Peer-to-Peer Networks
In this paper, we present a detail study about the immunization of viruses in Peer-to-Peer networks with power-law degree distributions. By comparing two different immunization strategies, we conclude that it is efficient to immunize the highly connected nodes in order to eradicate viruses from the network. Furthermore, we propose an efficient updating algorithm of global virus database according to the degree-based immunization strategy.
32567771
A Risk-Sensitive Intrusion Detection Model
Intrusion detection systems (IDSs) must meet the security goals while minimizing risks of wrong detections. In this paper, we study the issue of building a risk-sensitive intrusion detection model. To determinate whether a system calls sequence is normal or not, we consider not only the probability of this sequence belonging to normal sequences set or intrusion sequences set, but also the risk of a false detection. We define the risk model to formulate the expected risk of an intrusion detection decision, and present risk-sensitive machine learning techniques that can produce detection model to minimize the risks of false negatives and false positives. Meanwhile, this model is a hybrid model that combines misuse intrusion detection and anomaly intrusion detection. To achieve a satisfying performance, some techniques are applied to extend this model.
16524528
Thread detection in dynamic text message streams
Text message stream is a newly emerging type of Web data which is produced in enormous quantities with the popularity of Instant Messaging and Internet Relay Chat. It is beneficial for detecting the threads contained in the text stream for various applications, including information retrieval, expert recognition and even crime prevention. Despite its importance, not much research has been conducted so far on this problem due to the characteristics of the data in which the messages are usually very short and incomplete. In this paper, we present a stringent definition of the thread detection task and our preliminary solution to it. We propose three variations of a single-pass clustering algorithm for exploiting the temporal information in the streams. An algorithm based on linguistic features is also put forward to exploit the discourse structure information. We conducted several experiments to compare our approaches with some existing algorithms on a real dataset. The results show that all three variations of the single-pass algorithm outperform the basic single-pass algorithm. Our proposed algorithm based on linguistic features improves the performance relatively by 69.5% and 9.7% when compared with the basic single-pass algorithm and the best variation algorithm in terms of F1 respectively.
19624044
Hybrid Control of Automotive Powertrain Systems: A Case Study
In this paper, a hybrid control design approach is used to develop control strategies for coordination of automotive engine and transmission systems. The main goal is to improve system performance, fuel economy, robustness and other performance specifications. The method employs performance indices in guiding both analog and discrete control actions such that robust stability and performance of closed-loop hybrid systems are maintained, in the presence of modeling errors, disturbances and structural uncertainties.
84527
A comparison of implicit and explicit links for web page classification
It is well known that Web-page classification can be enhanced by using hyperlinks that provide linkages between Web pages. However, in the Web space, hyperlinks are usually sparse, noisy and thus in many situations can only provide limited help in classification. In this paper, we extend the concept of linkages from explicit hyperlinks to implicit links built between Web pages. By observing that people who search the Web with the same queries often click on different, but related documents together, we draw implicit links between Web pages that are clicked after the same queries. Those pages are implicitly linked. We provide an approach for automatically building the implicit links between Web pages using Web query logs, together with a thorough comparison between the uses of implicit and explicit links in Web page classification. Our experimental results on a large dataset confirm that the use of the implicit links is better than using explicit links in classification performance, with an increase of more than 10.5% in terms of the Macro-F1 measurement.
9435124
Z Approach to Semantic Web
The Semantic Web (SW) service is a web application using Semantic Web techniques which usually involve cooperation between several intelligent agents. The design of SW systems requires precise modelling techniques to capture ontology domain properties and application functionalities. We believe that Z as a specification technique can contribute to the Semantic Web-based system development in many ways. In this paper, we firstly conduct a case study of applying Z to the design of a SW service system (online talk discovery), and then present translation techniques and tools which can extract the SW ontology from the Z model automatically. Furthermore, we discuss how existing Z tools, i.e. Z/EVES, can be used to improve the quality of SW ontology design.
16117277
Hiding in the Crowd: Privacy Preservation on Evolving Streams through Correlation Tracking
We address the problem of preserving privacy in streams, which has received surprisingly limited attention. For static data, a well-studied and widely used approach is based on random perturbation of the data values. However, streams pose additional challenges. First, analysis of the data has to be performed incrementally, using limited processing time and buffer space, making batch approaches unsuitable. Second, the characteristics of streams evolve over time. Consequently, approaches based on global analysis of the data are not adequate. We show that it is possible to efficiently and effectively track the correlation and autocorrelation structure of multivariate streams and leverage it to add noise which maximally preserves privacy, in the sense that it is very hard to remove. Our techniques achieve much better results than previous static, global approaches, while requiring limited processing time and memory. We provide both a mathematical analysis and experimental evaluation on real data to validate the correctness, efficiency, and effectiveness of our algorithms.