Most algorithms developed for scheduling applications on global Grids focus on a single Quality of Service (QoS) parameter such as execution time, cost or total data transmission time. However, if we consider more tha...
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ISBN:
(纸本)9781595939449
Most algorithms developed for scheduling applications on global Grids focus on a single Quality of Service (QoS) parameter such as execution time, cost or total data transmission time. However, if we consider more than one QoS parameter (eg. execution cost and time may be in conflict) then the problem becomes more challenging. To handle such scenarios, it is convenient to use heuristics rather than a deterministic algorithm. In this paper we have proposed a workflow execution planning approach using Multiobjective Differential Evolution (MODE). Our goal was to generate a set of trade-off schedules according to two user specified QoS requirements (time and cost). The alternative tradeoff solutions offer more flexibility to users when estimating their QoS requirements of workflow executions. We have compared our results with two baseline multiobjective evolutionary algorithms. Simulation results show that our modified MODE is able to find a comparatively better spread of compromise solutions. Copyright 2007 ACM.
Tool support for the Java Modeling Language (JML) is a very pressing problem. A main issue with current tools is their architecture: the cost of keeping up with the evolution of Java is prohibitively high: e.g., almos...
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ISBN:
(纸本)9781595937216
Tool support for the Java Modeling Language (JML) is a very pressing problem. A main issue with current tools is their architecture: the cost of keeping up with the evolution of Java is prohibitively high: e.g., almost three years following its release, Java 5 has yet to be fully supported. This paper presents the architecture of JML4, an Integrated Verification Environment (IVE) for JML that builds upon Eclipse's support for Java, enhancing it with Extended Static Checking (ESC), an early form of Runtime Assertion Checking (RAC) and JML's non-null type system. Early results indicate that the synergy of complementary verification techniques (being made available within a single tool) can help developers be more effective;we demonstrate new bugs uncovered in JML annotated Java source - -like ESC/Java2 - -which is routinely verified using first generation JML tools. Copyright 2007 ACM.
The Bowl Championship Series (BCS) is the system used to select the top two college football teams to play in a championship game at the end of a season. During the nine seasons played under the BCS, few have not caus...
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The use of property classifications and patterns, i.e., high-level abstractions that describe common behavior have been shown to assist practitioners in generating formal specifications that can be used informal verif...
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ISBN:
(纸本)9780769530437
The use of property classifications and patterns, i.e., high-level abstractions that describe common behavior have been shown to assist practitioners in generating formal specifications that can be used informal verification techniques. The Specification Pattern System (SPS) provides descriptions of a collection of patterns. The extent of program execution over which a pattern must hold is described by the notion of scope. SPS provides a manual technique for obtaining formal specifications from a pattern and a scope. The Property Specification Tool (Prospec) extends SPS by introducing Composite Propositions (CPs), a classification for defining sequential and concurrent behavior to represent pattern and scope parameters, and provides a tool to support users. This work provides general templates for generating formal specifications in Linear Temporal Logic (LTL) for all pattern, scope, and CP combinations. In addition, the work explains the methodology for the verification of the correctness of these templates.
software patch generation is a critical phase in the life-cycle of a software vulnerability. The longer it takes to generate a patch, the higher the risk a vulnerable system needs to take to avoid from being compromis...
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ISBN:
(纸本)1595935746
software patch generation is a critical phase in the life-cycle of a software vulnerability. The longer it takes to generate a patch, the higher the risk a vulnerable system needs to take to avoid from being compromised. However, in practice, it is a rather lengthy process to generate and release software patches. For example, the analysis on 10 recent Microsoft patches (MS06-045 to MS06-054) shows that, for an identified vulnerability, it took 75 days on average to generate and release the patch. In this paper, we present the design, implementation, and evaluation of AutoPaG, a system that aims at reducing the time needed for software patch generation. In our current work, we mainly focus on a common and serious type of software vulnerability: the out-of-bound vulnerability which includes buffer overflows and general boundary condition errors. Given a working out-of-bound exploit which may be previously unknown, AutoPaG is able to catch on the fly the out-of-bound violation, and then, based on data flow analysis, automatically analyzes the program source code and identifies the root cause - vulnerable source-level program statements. Furthermore, within seconds, AutoPaG generates a fine-grained source code patch to temporarily fix it without any human intervention. We have built a proof-of-concept system in Linux and the preliminary results are promising: AutoPaG is able to successfully identify the root cause and generate a source code patch within seconds for every vulnerability test in the Wilander's buffer overflow benchmark test-suite. In addition, the evaluation with a number of real-world out-of-bound exploits also demonstrates its effectiveness and practicality in automatically identifying (vulnerable) source code root causes and generating corresponding patches. Copyright 2007 ACM.
Java has recently joined C and C++ as a relatively high-level language suitable for developing real-time applications. Java's garbage collection, while generally a useful feature, can be problematic for real-time ...
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This paper presents a cross-modal approach of image retrieval from a medical image collection which integrates visual information based on purely low-level image contents and case related textual information from the ...
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Block motion estimation with full search is computationally complex. To reduce this complexity, different methods have been proposed, including partial distortion, which can reduce the computational complexity with no...
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ISBN:
(纸本)9781424410163
Block motion estimation with full search is computationally complex. To reduce this complexity, different methods have been proposed, including partial distortion, which can reduce the computational complexity with no loss of image quality. We propose a distortion-based partial distortion search (DPDS) based on the magnitude of distortion and adaptive update of the matching order. We calculate absolute differences for all pixels in the predicted block point. Pixels are then sorted by the amount of distortion in a descending order for the matching process, which produces a scanning map. The sum of the absolute differences (SAD) of other candidate positions is then computed from this matching order. We also use an update of the scanning map by checking the increase in the number of absolute differences for the SAD value. The proposed DPDS algorithm improves the computational efficiency, compared with the original PDS scheme, because the accumulated value of the absolute pixel differences can rapidly reach the current minimum SAD value. The proposed algorithm is 4-13 times faster than the full search method with the same visual quality.
Publish/Subscribe model has become a prevalent paradigm for building distributed event delivering systems. Content-based publish/subscribe allows high expresses in subscriptions and thus is more appropriate for conten...
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The availability of multiple rates in IEEE8O2. 11 WLANs and instability of wireless channel conditions call for data rate adaption algorithms to optimize network performance. Rate adaption is the process of assessing ...
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The availability of multiple rates in IEEE8O2. 11 WLANs and instability of wireless channel conditions call for data rate adaption algorithms to optimize network performance. Rate adaption is the process of assessing instantaneous channel conditions and determining the most appropriate data rate. This paper presents a relaxed probing rate adaptation scheme to determine the most appropriate instantaneous data rate for both downlink and uplink channels, especially in the case where control frames such as RTSICTS are not available. For this goal, the proposed scheme exploits the mandatory management beacon frame, thus without requiring probing frames like RTS/CTS necessary for other so far proposed schemes. Ns-2 simulations with IEEE8O2. 1 lb of the proposed scheme yield more than 100% throughput improvement in high density networks. Also, simulations show that the proposed scheme is insensitive to beacon interval.
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