TCP uses packet loss as a feedback from the network to adapt its sending rate. TCP keeps increasing its sending rate as long as no packet loss occurs (unless constrained by buffer size). Alternative congestion avoidan...
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ISBN:
(纸本)9781581137736
TCP uses packet loss as a feedback from the network to adapt its sending rate. TCP keeps increasing its sending rate as long as no packet loss occurs (unless constrained by buffer size). Alternative congestion avoidance techniques (CATs) have been proposed to avoid such "aggressive" behavior. These CATs use simple statistics on observed round-trip times and/or throughput of a TCP connection in response to variations in congestion window size. These CATs have a supposed ability to detect queue build-up. The objective of this paper is to question the ability of these CATs to reliably detect queue build-up under real network conditions. For this purpose, the sample coefficient of correlation between round-trip time and the number of packets in flight is analyzed for 14,218 connections over 737 Internet paths. These coefficients of correlation were extracted from a set of tcpdump traces collected by Vern Paxson. The coefficients of correlation measured confirm that the correlation between RTT and window size is often weak. Copyright 2003 ACM.
For a multi-agent system to work according to its specifications, the individual agents that compose it must abide by the interaction protocol that binds their actions. This interaction protocol delimits what the agen...
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Distributed resource allocation is a fundamental problem in construction of distributed systems. Though a lot of distributed algorithms have been developed for the problem, many of them are only designed to satisfy th...
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ISBN:
(纸本)0769519067
Distributed resource allocation is a fundamental problem in construction of distributed systems. Though a lot of distributed algorithms have been developed for the problem, many of them are only designed to satisfy the desired quality of the requested resources, without considering acceptable range of the quality of the requested resources. In this paper we propose a new distributed algorithm employing a concession method, by which a process can transfer a reserved resource to another process, so that more processes can use the resources in the same time, to increase the efficiency and still keep the satisfaction for the quality of the resources in an acceptable range. We redefine the problem, and give the design and implementation of the algorithm in the paper.
Some recent developments in the μCRL tool set are presented. New analysis techniques are a symbolic model checker, and a visualizer for huge state spaces. Also various transformations are presented. At symbolic level...
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Some recent developments in the μCRL tool set are presented. New analysis techniques are a symbolic model checker, and a visualizer for huge state spaces. Also various transformations are presented. At symbolic level, theorem proving, data flow analysis, and confluence checking are used to obtain considerable state space reductions. At the concrete level, distributed implementations of state space generation and minimization are recent. We mention the successful application of the tools to the verification of large data-intensive distributed systems.
A new algorithm is proposed to solve constrained multiobjective problems. The constraints of the MOPs are taken account of in determining Pareto dominance. As a result, the feasibility of solutions is not an issue. At...
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software components realising the graphical user interface (GUI) of a highly interactive system or the user interface of a Web application form an essential part of the entire implementation and significantly affect t...
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Configuration testing is an important step in software testing, which is a procedure to test the software with all kinds of hardware to ensure it can run on them. This paper proposes to design configuration testing pl...
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ISBN:
(纸本)193241519X
Configuration testing is an important step in software testing, which is a procedure to test the software with all kinds of hardware to ensure it can run on them. This paper proposes to design configuration testing plan with several common method used in the other fields and analysis their merits, to improve the orthogonal design method with pairwise testing, to decrease the testing risk with multiple factors covering., and presents simple factor cover method which can cover all the factors and pairwise combinations to the greatest degree. All these methods have good merits. At last we make some comparison at the aspects of test suit scale, coverage, usability and etc.
In a practical sense, rigorous procedures for generating use cases are not well defined. In addition, the relationship between functional requirements and use cases is not clearly understood or easy to quantify. In th...
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It is general process of client authentication for a user to gain authority by the user’s ID and password. But using client’s password is not always secure because of various security attacks of many opponents. In t...
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The traditional thrust of software quality assurance has been to use "brute force" testing at the end of development. However quality assurance in the early phases of development is an order of magnitude mor...
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ISBN:
(纸本)1581136722
The traditional thrust of software quality assurance has been to use "brute force" testing at the end of development. However quality assurance in the early phases of development is an order of magnitude more cost effective than testing done at the end of development. This paper describes the introduction of quality reviews as a learning activity into an undergraduate requirements analysis course, and evaluates the effectiveness of this in improving learning. In the absence of any standard instrument for evaluating learning effectiveness, we developed a survey instrument called the Learning Effectiveness Survey. Using this instrument, learning effectiveness is evaluated in the context of the learning goals of the course (short term learning), and in the context of the broader educational programme and future working life (long term learning). It also provides feedback on the learning intervention and how it can be improved. While the intervention was moderately successful in its first application, a great deal was learned about how it could be improved next time.
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