The Gridbus workflow management system (GWMS) is designed to execute scientific applications, expressed in the form of workflows, onto Grid and Cloud resources. With the help of this system, we demonstrate a computati...
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The Gridbus workflow management system (GWMS) is designed to execute scientific applications, expressed in the form of workflows, onto Grid and Cloud resources. With the help of this system, we demonstrate a computational and data-intensive Image Registration (IR) workflow for functional Magnetic Resonance Imaging (fMRI) applications on Clouds and global Grids. We also present a demonstration of the Aneka System. Aneka is a .NET based Cloud software platform that provides: (i) a configurable service container hosting pluggable services for discovering, scheduling various types of workloads and (ii) a flexible and extensible framework supporting various programming models. We use distributed Grid and Cloud resources from Australia, Austria, France, Japan, and USA for the executions of image registration workflow, and resources from Melbourne University for executing map-reduce applications in Aneka cloud environment.
The MapReduce programming model allows users to easily develop distributed applications in data centers. However, many applications cannot be exactly expressed with MapReduce due to their specific characteristics. For...
The MapReduce programming model allows users to easily develop distributed applications in data centers. However, many applications cannot be exactly expressed with MapReduce due to their specific characteristics. For instance, genetic algorithms (GAs) naturally fit into an iterative style. That does not follow the two phase pattern of MapReduce. This paper presents an extension to the MapReduce model featuring a hierarchical reduction phase. This model is called MRPGA (MapReduce for parallel GAs), which can automatically parallelize GAs. We describe the design and implementation of the extended MapReduce model on a .NET-based enterprise grid system in detail. The evaluation of this model with its runtime system is presented using example applications.
We model the Sum and Product Riddle inpublic announcement logic, which is interpreted on an epistemic Kripke model. The model is symbolically represented as a finite state program with n agents. A model checking metho...
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In this paper, we proposed an efficient algorithm, TOPK_CLOSED, for mining top-k closed itemsets. This algorithm mines top-k closed itemsets using best-first search. The closed itemsets with the highest supports are f...
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In this paper, we proposed an efficient algorithm, TOPK_CLOSED, for mining top-k closed itemsets. This algorithm mines top-k closed itemsets using best-first search. The closed itemsets with the highest supports are firstly found from this algorithm. Consequently, the method quickly finds top-k closed itemsets, which leads to an efficient pruning unnecessary itemsets and stop mining rapidly. In addition, this algorithm can generate closed itemsets without keeping candidates in main memory.
It is becoming increasingly important to be able to adapt an application's behavior at run time in response to changing requirements and environmental conditions. Adaptive programs are typically difficult to speci...
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It is becoming increasingly important to be able to adapt an application's behavior at run time in response to changing requirements and environmental conditions. Adaptive programs are typically difficult to specify, design, and verify. A variety of conditions may trigger an adaptation, each of which may involve different types of adaptation mechanisms. In many cases, adaptive systems are concurrent, thus further exacerbating the complexity. Furthermore, it is important that adaptations do not put the system into an inconsistent state during or after adaptation. This paper presents an iterative approach to modeling and analyzing UML behavioral design models of adaptive systems, where the UML state diagrams are automatically translated into Promela code for analysis with the Spin model checker. The adaptive models are analyzed for adherence to both system invariants and properties that should hold during adaptation. We demonstrate this approach on applications for the mobile computing domain where we verify the design models against formally-specified properties.
A content delivery network (CDN) is expected to provide high performance content delivery, which requires scalable infrastructure to achieve global coverage. The provision of such infrastructure may form a substantial...
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A content delivery network (CDN) is expected to provide high performance content delivery, which requires scalable infrastructure to achieve global coverage. The provision of such infrastructure may form a substantial entry barrier for new CDN providers, as well as affecting commercial viability of the existing ones. Peering of CDNs can be a way to allow dynamic infrastructural cooperation between CDNs in a scalable manner, in order to mitigate the impact of flash crowds and to achieve better overall service times. In this paper, we present a quality of service (QoS)-driven model to evaluate the user perceived performance of CDN peering relationships. In this model, an overloaded CDN redirects a fraction of its incoming requests to peered CDNs and thereby can avoid the impact of flash crowds. The model-based approach also assists in making concrete QoS guarantee for a given CDN. Our approach endeavors to achieve scalability for a CDN in a user transparent manner.
This paper examines transformational learning experiences of computing students as a way to better understand threshold concepts in computing. From empirical evidence we found that students often describe transformati...
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ISBN:
(纸本)9781605582160
This paper examines transformational learning experiences of computing students as a way to better understand threshold concepts in computing. From empirical evidence we found that students often describe transformative experiences as learning situations in which they were led to use various kinds of abstraction, for example modularity, data abstraction, inheritance, polymorphism, reuse, design patterns, and complexity. Some students describe an abstract concept as coming first, and then needing to be made concrete though application;others describe transformations in which they learn the advantages of these abstract concepts from their experience of not using them. Abstraction is certainly of central importance in computerscience. It appears, however, from our students' descriptions of transformative experiences, that abstraction per se is not a threshold, but that particular concepts in which abstraction is paramount exhibit the characteristics of threshold concepts. Copyright 2008 ACM.
Search engines on the Web have popularized the keyword-based search paradigm, while searching in databases users need to know a database schema and a query language. Keyword search techniques on the Web cannot directl...
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Search engines on the Web have popularized the keyword-based search paradigm, while searching in databases users need to know a database schema and a query language. Keyword search techniques on the Web cannot directly be applied to databases because the data on the Internet and database are in different forms. Moreover, existing systems for keyword searching limit type of keywords to database value terms. Thus, this research aims to propose a new method for keyword searching in databases which allows users to search either with database value terms, metadata terms or user terms. The metadata model accommodates these terms as well as underlying database semantics.
In this paper, a class of hybrid impulsive systems with time delays and stochastic effects are considered. We obtain some criteria on the global exponential stability in mean square for the impulsive stochastic delaye...
In this paper, a class of hybrid impulsive systems with time delays and stochastic effects are considered. We obtain some criteria on the global exponential stability in mean square for the impulsive stochastic delayed systems. To do this, differential inequalities and ℒ-operator inequalities are developed. An example is given to illustrate the effectiveness of our results.
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