Interval Type-2 Fuzzy Sets (IT2 FSs) has been used in wide range of applications, such as decision making, pattern recognitions. However, there is little investigation on the clustering techniques of IT2 FSs, since it...
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Interval Type-2 Fuzzy Sets (IT2 FSs) has been used in wide range of applications, such as decision making, pattern recognitions. However, there is little investigation on the clustering techniques of IT2 FSs, since it is very important for measuring the degree of similarity between interval type-2 fuzzy sets in clustering research. In this paper, we give a novel method to represent interval type-2 fuzzy sets by a series of linear functions. This method is named as triangular representation because the curves of the functions and the coordinates shape into triangles. A new kind of similarity between interval type-2 fuzzy sets based on triangle is given and the validity of this method is proven. Furthermore, several numerical examples are given to show that the proposed similarity measure is reasonable and better than any existing methods.
With the development of virtualization technology, file protection in virtual machine, especially in guest OS, becomes more and more important. Traditional host-based file protection system resides the critical module...
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With the development of virtualization technology, file protection in virtual machine, especially in guest OS, becomes more and more important. Traditional host-based file protection system resides the critical modules in monitored system, which is easily explored and destroyed by malwares. Moreover, in order to protect the multiple operation systems running on the same platform, it is necessary to install independent file protection system for each of them, which greatly wastes computing resources and brings serious performance overhead. In this paper, a novel VM-based real-time file protection system, named VRFPS, is proposed to solve these problems. First, virtual machine monitor introspects all file operations of guest OS. Then, semantic gap between disk block and logic files is narrowed by blktap. Finally, a virtual sandbox is implemented in privileged domain to prevent protected files in guest domain from modifying illegally. Our approach is highly isolated, transparent and without modification on virtual machine monitor and guest OS. The experimental results show that the presented system is validate and of low performance overhead.
Performance monitor for virtual machines can monitor the performance metrics of virtual machines and gain the resource consumption status, and thus provide reliable basis for system performance evaluation and further ...
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Performance monitor for virtual machines can monitor the performance metrics of virtual machines and gain the resource consumption status, and thus provide reliable basis for system performance evaluation and further management. However, at current stage, such performance monitor systems for the virtualized systems are inadequate and inefficient. In this paper, we propose a lightweight performance monitor system model for virtual machines, called PMonitor. Through prototype implementation and experiments, we find that PMonitor consumes very few processing power, which is much lower than other open source performance monitors running on the virtualized environments.
Range query in DHT based P2P network is a hot topic in recent researches. The hashing function in DHT protocols makes the data hard to keep their original order relationship. Hence range queries for such networks beco...
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Range query in DHT based P2P network is a hot topic in recent researches. The hashing function in DHT protocols makes the data hard to keep their original order relationship. Hence range queries for such networks become difficult. This paper presents the design of Yarqs-a new schema to achieve range queries in DHT based P2P networks. By using the inherent characteristics of DHT based networks, Yarqs catches the data pass the nodes and organizes them as a cache network. The range queries are deployed over the cache network. Yarqs does not change the design of the DHT overlay and builds the architecture for range queries by using the historical DHT queries data. Yarqs supports inherent load balancing. We also study the performance of Yarqs in evaluation section. The experiments to check the influences of different parameters of Yarqs are deployed and analyzed.
Live migration of virtual machines has been a powerful tool to facilitate system maintenance, load balancing, fault tolerance, and power-saving, especially in clusters or data centers. Although pre-copy is a predomina...
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Live migration of virtual machines has been a powerful tool to facilitate system maintenance, load balancing, fault tolerance, and power-saving, especially in clusters or data centers. Although pre-copy is a predominantly used approach in the state of the art, it is difficult to provide quick migration with low network overhead, due to a great amount of transferred data during migration, leading to large performance degradation of virtual machine services. This paper presents the design and implementation of a novel memory-compression-based VM migration approach (MECOM) that first uses memory compression to provide fast, stable virtual machine migration, while guaranteeing the virtual machine services to be slightly affected. Based on memory page characteristics, we design an adaptive zero-aware compression algorithm for balancing the performance and the cost of virtual machine migration. Pages are quickly compressed in batches on the source and exactly recovered on the target. Experiment demonstrates that compared with Xen, our system can significantly reduce 27.1% of downtime, 32% of total migration time and 68.8% of total transferred data on average.
Virtual machine (VM) level checkpoints bring several advantages which process-level checkpoint implementation can hardly provide: compatibility, transparence, flexibility, and simplicity. However, the size of VM-level...
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Virtual machine (VM) level checkpoints bring several advantages which process-level checkpoint implementation can hardly provide: compatibility, transparence, flexibility, and simplicity. However, the size of VM-level checkpoint may be very large and even in the order of gigabytes. This disadvantage causes the VM checkpointing and restart time become very long. To reduce the size of VM checkpoint, this paper proposes a memory exclusion scheme using ballooning mechanism, which omits saving unnecessary free pages in the VM. We implement our prototype in Xen environment. Experimental measurements show our approach can significantly reduce the size of VM checkpoint with minimal runtime overhead, thereby greatly improve the checkpoint performance.
Virtual desktop environment (VDE) provides a real virtual working environment in which users could personally customize and update the application list from application template libraries. The heterogeneous applicatio...
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Virtual desktop environment (VDE) provides a real virtual working environment in which users could personally customize and update the application list from application template libraries. The heterogeneous applications actually running in the remote application servers could cooperatively communicate with each other. It is a thin client approach to mobility in which the perfect combination of VM technology and DFS technology are the keys to the rapid seamless resuming of the usage scenarios. Usage scenarios are incrementally suspended including the user's documents and the running applications. The usage data stored in data center provides a unified view for the users through historical scenario manager and ensures the data's security and reliability at the same time. This paper explores the building policy of a real virtual working environment and the suspending/resuming policy of usage scenarios. Experiments demonstrate and evaluate VDE's efficiency and effectiveness.
Interval type-2 fuzzy set is the most popular kind of type-2 fuzzy set, its characteristic is that all the secondary membership functions equal to 1. Though interval type-2 fuzzy sets can reduce the calculation comple...
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Interval type-2 fuzzy set is the most popular kind of type-2 fuzzy set, its characteristic is that all the secondary membership functions equal to 1. Though interval type-2 fuzzy sets can reduce the calculation complexity than other type-2 fuzzy sets, it loses much fuzzy information simultaneously. In order to solve this problem we propose a novel theory of triangle type-2 fuzzy sets, the formulas for union, intersection and complement of triangle type-2 fuzzy sets are derived and proven in detail. In addition, the relationship and the conversion between triangle type-2 fuzzy sets and interval type-2 fuzzy sets are discussed.
With the resurgence of virtual machine technology, vendors build virtualization technology support in the processors. Virtual machines relying on such support are called Hardware-assisted Virtual Machines (HVM guests ...
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With the resurgence of virtual machine technology, vendors build virtualization technology support in the processors. Virtual machines relying on such support are called Hardware-assisted Virtual Machines (HVM guests for short). Although HVM guests have the advantage that they do not need to revise the source code of operating systems running inside, the processing of I/O operations in HVM is much complicated and the performance of such operations are rather low. In this paper, we conduct a performance study on the Web server running inside the HVM guests by using queuing network modeling technique, and analyze the performance bottlenecks of the systems.
Agent-based grid data loading method aims at integrating heterogeneous hospitalspsila information systems into a medical information exchange platform based on grid middleware. It collects distributed data sets for de...
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Agent-based grid data loading method aims at integrating heterogeneous hospitalspsila information systems into a medical information exchange platform based on grid middleware. It collects distributed data sets for decision support system, which makes data sources expanded from independent database modes to medical information systems in wide area. Virtual data access with grid service improves data security and makes data modification in local system more flexible. HL7 protocol and middleware are utilized to transform HL7 data into various local data structures for keeping the independence of each hospital information system and providing more convenience and expansibility for various medical applications.
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