Checkpointing is widely used in robust fault-tolerant applications. We present an efficient incremental checkpointing mechanism. It requires to record only the state changes and not the complete state. After the creat...
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ISBN:
(纸本)9781424405015
Checkpointing is widely used in robust fault-tolerant applications. We present an efficient incremental checkpointing mechanism. It requires to record only the state changes and not the complete state. After the creation of a checkpoint, state changes are logged incrementally as records in memory, with which an application can spontaneously roll back later. This incrementalism allows us to implement checkpointing with high performance. Only small constant time is required for checkpoint creation and state recording. Rollback requires linear time in the number of recorded state changes, which is bounded by the number of state variables times the number of checkpoints. We implement a Java source transformer that automatically converts an existing application into a behavior-preserving one with checkpointing functionality. This transformation is application-independent and application-transparent. A wide range of applications can benefit from this technique. Currently, it has been used for distributed discrete event simulation using the time warp technique
Over the last few years, grid technologies have progressed towards a service-oriented paradigm that enables a new way of service provisioning based on utility computing models. Users consume these services based on th...
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Over the last few years, grid technologies have progressed towards a service-oriented paradigm that enables a new way of service provisioning based on utility computing models. Users consume these services based on their QoS (quality of service) requirements. In such “pay-per-use” grids, workflow execution cost must be considered during scheduling based on users' QoS constraints. In this paper, we propose a budget constraint based scheduling, which minimizes execution time while meeting a specified budget for delivering results. A new type of genetic algorithm is developed to solve the scheduling optimization problem and we test the scheduling algorithm in a simulated grid testbed.
This paper describes Threshold Concepts, a theory of learning that distinguishes core concepts whose characteristics can make them troublesome in learning. With an eye to applying this theory in computer science, we c...
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ISBN:
(纸本)1595936033
This paper describes Threshold Concepts, a theory of learning that distinguishes core concepts whose characteristics can make them troublesome in learning. With an eye to applying this theory in computer science, we consider this notion in the context of related topics in computer science education.
Services such as audio/video streaming, advertising, and software distribution can be delivered much more efficiently by network service providers if multicast data distribution is used. However, accounting for the re...
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Services such as audio/video streaming, advertising, and software distribution can be delivered much more efficiently by network service providers if multicast data distribution is used. However, accounting for the resources consumed by subscribers becomes essential. Using an e-commerce (payment recovery) operational environment, in turn, requires support for security properties such as authentication, authorization, data confidentiality, and non-repudiation. However, multicast data distribution is inherently more susceptible to attack than unicast distribution, given its greater susceptibility to interception of the network traffic. Securing multicast sessions in B2C commerce requires authentication of the end-host, authorization of the subscriber and his e-payments, and accounting for a subscriber's consumed resources. In this paper, we present a comprehensive survey of the literature on e-payment platforms and protocols that provide some form of security to e-commerce transactions, followed by a comparative study of these e-payment platforms and protocols. We show the security problems that are currently unaddressed by the existing multicast protocols and e-payment platforms and protocols, in securing the operating environment of B2C commerce for multicast networks
Autonomic computersystems adapt themselves to cope with changes in the operating conditions and to meet the service-level agreements with a minimum of resources. Changes in operating conditions include hardware and s...
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Autonomic computersystems adapt themselves to cope with changes in the operating conditions and to meet the service-level agreements with a minimum of resources. Changes in operating conditions include hardware and software failures, load variation and variations in user interaction with the system. The self adaptation can be achieved by tuning the software, balancing the load or through hardware provisioning. This paper investigates a feed-forward adaptation scheme in which tuning and provisioning decisions are based on a dynamic predictive performance model of the system and the software. The model consists of a layered queuing network whose parameters are tuned by tracking the system with an Extended Kalman Filter. An optimization algorithm searches the system configuration space by using the predictive performance model to evaluate every configuration.
We propose a new method, called closed multidimensional sequential pattern mining, for mining multidimensional sequential patterns. The new method is an integration of closed sequential pattern mining and closed items...
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We propose a new method, called closed multidimensional sequential pattern mining, for mining multidimensional sequential patterns. The new method is an integration of closed sequential pattern mining and closed itemset pattern mining. Based on this method, we show that (1) the number of complete closed multidimensional sequential patterns is not larger than the number of complete multidimensional sequential patterns (2) the set of complete closed multidimensional sequential patterns covers the complete resulting set of multidimensional sequential patterns. In addition, mining using closed itemset pattern mining on multidimensional information would mine only multidimensional information associated with mined closed sequential patterns, and mining using closed sequential pattern mining on sequences would mine only sequences associated with mined closed itemset patterns
The change in the softwaresystems is inevitable if the system is to remain useful. The change in business requirements sometimes is such that the old and new requirements have to be met simultaneously, i.e. old and n...
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The change in the softwaresystems is inevitable if the system is to remain useful. The change in business requirements sometimes is such that the old and new requirements have to be met simultaneously, i.e. old and new business rules are needed to exist concurrently. Accommodating more than one rule in the existing entities, leads to the change in the operational system, which involves risk. The evolution in the system impacts the business rules as well as the data model of the system. The evolution step incorporating the change in business rule requires changes to be carried out in the application architecture in terms of addition or modification of process as well as data components and also the alterations in the relationships among the components. The evolution problem of coexistence of business rules can be considered as incremental change to the existing architectural design of the system to nullify the risk of change to the software. In this paper we propose the framework, where temporal aspects of process as well as data components and concurrent validity of multiple business rules, with multiple versions of the components can be effectively implemented. The framework supports evolution without disturbing existing architecture and functionality. This framework is consistent in application to systems irrespective of the design methodology followed for the same.
An algorithm for time division multiple access (TDMA) is found to be applicable in converting existing distributed algorithms into a model that is consistent with sensor networks. Such a TDMA service needs to be self-...
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This paper assesses and analyzes a harmonic vector modeling method for reducing disturbance torque and motion state estimation error using quantized input measurements of position. There is a finite resolution availab...
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This paper assesses and analyzes a harmonic vector modeling method for reducing disturbance torque and motion state estimation error using quantized input measurements of position. There is a finite resolution available for any digital interface and quantization will always be present in some form. Although not possible to completely reconstruct a quantized measured state, it is possible to attenuate deterministic quantization characteristics. The discussed method models quantized position feedback as a spatially rotating vector consisting of fundamental and harmonic components. The error mitigation strategy involves decoupling these spatial quantization harmonics from the actual fundamental position, using heterodyning tracking observer topologies
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