Recently, the impact of design patterns on software quality has attracted a gradual attention since design patterns encapsulate valuable knowledge to resolve design problems and improve design quality. As an attempt t...
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ISBN:
(纸本)9078677015
Recently, the impact of design patterns on software quality has attracted a gradual attention since design patterns encapsulate valuable knowledge to resolve design problems and improve design quality. As an attempt towards the investigation of applying goals and design patterns to realize the model transformation, we proposed, in this paper, a goal-driven model transformation by applying design patterns to transform an analysis model into its corresponding design model with an emphasis on the non-functional requirements. The use of goals makes it easier to transform the functional and non-functional requirements into the software models, and derives the candidate design patterns to help satisfy nonfunctional requirements for resolving the design problems and improving software quality.
The detection of failures is a fundamental issue for fault tolerance in distributed systems. Recently, many people have come to realize that failure detection ought to be provided as some form of generic service, simi...
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ISBN:
(纸本)0769524664
The detection of failures is a fundamental issue for fault tolerance in distributed systems. Recently, many people have come to realize that failure detection ought to be provided as some form of generic service, similar to IP address lookup. However, this has not been successful so far;one of the reasons being the fact that classical failure detectors were not designed to satisfy several application requirements simultaneously. More specifically, traditional implementations of failure detectors are often tuned for running over local networks and fail to address some important problems found in wide-area distributed systems with a large number of monitored components. In this paper, we study the quality of service (QoS) of failure detectors. We first present a novel failure detector scheme combined with control theory that can help in solving or optimizing some problems. Furthermore, this paper discusses the design and analysis of implementing a scalable failure detection service for such large wide-area distributed systems considering dynamically adjusting the heartbeat streams, so that it satisfies the bottleneck router requirements. We further show how the online failure detector control algorithm can be used to design a controller, analyze the theoretical aspects of the proposed algorithm and verify its agreement. Simulation results show the efficiency of our scheme in terms of high utilization of the bottleneck link fast response and good stability of the bottleneck router buffer occupancy as well as of the controlled sending rates. In conclusion, the new failure detector algorithm provides a better QoS than an algorithm that is proposed by Stelling et al [1, 2].
We present a Secure E-commerce Protection Profile (SEPP) that captures security requirements for securing sessions in the e-commerce operational environment. The SEPP is prepared in accordance with the Common Criteria...
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ISBN:
(纸本)1601320019
We present a Secure E-commerce Protection Profile (SEPP) that captures security requirements for securing sessions in the e-commerce operational environment. The SEPP is prepared in accordance with the Common Criteria (CC), Version 2.1, as specified by the ISO 15408 standard. The SEPP states the requirements that sessions must satisfy in order to respond to the needs of e-commerce. The Target of Evaluation (TOE) security environment, which is composed of threat agents, vulnerabilities, attacks and threats, is described in detail. It is followed by describing the administrative security policies that are necessary to safeguard the TOE or its operating environment. The risks to the TOE are identified. The security objectives for the TOE are stated.
With the ever-increasing data transmission applications recently, considerable efforts have been focused on the design of congestion control scheme for data transmission service to guarantee the quality of service (Qo...
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ISBN:
(纸本)142440133X
With the ever-increasing data transmission applications recently, considerable efforts have been focused on the design of congestion control scheme for data transmission service to guarantee the quality of service (QoS). The main difficulty in designing an efficient congestion controller for data transmission service stems from the heterogeneous receivers, especially those with large propagation delays in data transfer, which also mean the feedbacks arriving at the source are somewhat outdated and can be harmful to the control actions. This usually leads to a mismatch between the network resources and the amount of admitted traffic. To attack this problem, the present paper describes a novel congestion control scheme that is based on a Back Propagation (BP) neural network technique. We consider a general computer communication model with multiple sources and one destination node. This network-assisted property is different from the existed control scheme in that the data source can predict the dynamic of buffer occupancy of the bottleneck node for which the back control packets experience very long propagation delay and probably cause irresponsiveness of a. data flow. This active scheme makes the control more responsive to the network status. Thus the rate adaptation can be in a timely manner for the sender to react to network congestion quickly. We analyze the theoretical aspects of the proposed algorithm, show how the control mechanism can be used to design a controller to support the data transmission based on feedback of explicit rates' (ER's), and verify this agreement by the simulations. Simulation results show the efficiency of our scheme in terms of quickly response and excellent predictive accuracy.
In the automotive field, software development methods and tools are used to cope with the high complexity of automotive software development. However, problems occur with the tracing of information, the assessment and...
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This paper presents an improved C-means clustering algorithm based on ACO. The proposed method use pheromone to evaluate individual colony's iterative result. In contrast with the existing C-means clustering algor...
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This paper presents technical foundation, roadmap and initial results of the IDIOM project (information Diffusion across Interactive Online Media). information spreads rapidly across Web sites, Web logs and online for...
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Active Queue Management (AQM) is an effective method used in Internet routers for congestion control, and to achieve a tradeoff between link utilization and delay. The de facto standard, the Random Early Detection (RE...
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ISBN:
(纸本)1424402212
Active Queue Management (AQM) is an effective method used in Internet routers for congestion control, and to achieve a tradeoff between link utilization and delay. The de facto standard, the Random Early Detection (RED) AQM scheme, and most of its variants use average queue length as a congestion indicator to trigger packet dropping. This paper proposes a novel AQM algorithm, called Self-tuning Proportional and Integral RED (SPI-RED), as an extension of RED. SPI-RED is based on a Self-tuning Proportional and Integral controller, which not only considers the average queue length at the current time point, but also takes into consideration the past average queue lengths during a round-trip time. Furthermore, we give theoretical analysis of the system stability and give guidelines for the selection of feedback gains for the TCP/RED system to stabilize the average queue length at a desirable level. Extensive simulations have been conducted with ns2. The simulation results have demonstrated that the proposed SPI-RED algorithm outperforms the existing AQM schemes in terms of drop probability and stability.
This paper describes a data replication service for large-scale, data intensive applications whose results can be shared among geographically distributed scientists. We introduce two kinds of data replication techniqu...
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Active Queue Management (AQM) is an effective method used in Internet routers to enhance congestion control, and to achieve a trade off between link utilization and delay. The de facto standard, the Random Early Detec...
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