Many parallel scientific applications have dynamic and irregular computational structure. However, most such applications exhibit persistence of computational load and communication structure. This allows us to embed ...
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We describe a class of attacks that can compromise the privacy of users' Web-browsing histories. The attacks allow a malicious Web site to determine whether or not the user has recently visited some other, unrelat...
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ISBN:
(纸本)9781581132038
We describe a class of attacks that can compromise the privacy of users' Web-browsing histories. The attacks allow a malicious Web site to determine whether or not the user has recently visited some other, unrelated Web page. The malicious page can determine this information by measuring the time the user's browser requires to perform certain operations. Since browsers perform various forms of caching, the time required for operations depends on the user's browsing history;this paper shows that the resulting time variations convey enough information to compromise users' privacy. This attack method also allows other types of information gathering by Web sites, such as a more invasive form of Web "cookies". The attacks we describe can be carried out without the victim's knowledge, and most "anonymous browsing" tools fail to prevent them. Other simple countermeasures also fail to prevent these attacks. We describe a way of reengineering browsers to prevent most of them.
We introduce a generalization of the spreadsheet paradigm, called Knowledgesheet, for solving a class of constraint satisfaction problems. The traditional spreadsheet paradigm is based on attaching arithmetic expressi...
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Presents a new commerce protocol that allows customers and merchants to conduct face-to-face credit-card authorizations with a credit card company securely, with the option of anonymity for the customer, the merchant,...
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Presents a new commerce protocol that allows customers and merchants to conduct face-to-face credit-card authorizations with a credit card company securely, with the option of anonymity for the customer, the merchant, or both. Our protocol guarantees that both parties agree to and know the outcome of each transaction. Our protocol has three advantages over others. First, we need only two message authentication code (MAC) operations per party per transaction, fewer than most popular protocols. Second, our own MAC function, OTPMAC (One-Time Pad MAC), does not rely on the existence of one-way functions or on any other unproven hypothesis. Third, our protocol generates a new one-time identifier per party per transaction, preventing the linkage of multiple transactions to a single party. Additionally, the protocol can operate in modes using alternatives to the one-time pad, including cryptographic pseudo-random number generators and conventional cryptographic MAC functions.
作者：
Chris McDonaldKamran KazemiProgramming
Languages and Systems Group Department of Computer Science The University of Western Australia Nedlands Western Australia 6907
Parallel algorithms are often introduced to students by describing the geometric topologies formed by communicating processes and often the geographic relationships between them. However, the two most common message p...
ISBN:
(纸本)9781581132137
Parallel algorithms are often introduced to students by describing the geometric topologies formed by communicating processes and often the geographic relationships between them. However, the two most common message passing environments used in teaching, PVM and MPI, each provide only rudimentary support for the specification and execution of process topologies. There is a strong need for better syntactic and semantic support for process topologies in these environments, so that students may concentrate on the algorithms being studied, and not have to wrestle with the environments' infrastructure. This paper first motivates, and then describes the use of additional support within PVM and MPI which addresses this need.
Separation of concerns is at the heart of software development, and although its benefits have been well established, the core problem remains how to achieve it. For complex software systems the solution is still deba...
Separation of concerns is at the heart of software development, and although its benefits have been well established, the core problem remains how to achieve it. For complex software systems the solution is still debatable and it is a major research area. Object Oriented programming (OOP) works well only if the problem at hand can be described with relatively simple interface among objects. Unfortunately, this is not the case when we move from sequential programming to concurrent and distributed programming. The September 1993 CACM issue was devoted to the problematic marriage between OOP and Concurrency [Cohen 93]. Since then, numerous workshops, articles and books have attempt to tackle the problem. The core complexity is that concurrent and distributed systems manifest over more than one dimension. Features such as scheduling, synchronization, fault tolerance, security, testing and verifications are all expressed in such a way that they tend to cut across different objects. Hence, simple object interfaces are violated and the traditional OOP benefits no longer hold. One of the current attempts to resolve this issue is the Aspect Oriented Software Architecture. To address this multi-dimensional structure of concurrent systems we distinguish between components and aspects. Aspects are defined as properties of a system that do not necessarily align with the system’s functional components but tend to cut across functional components, increasing their interdependencies, and thus affecting the quality of the software. Although not bound to OOP, Aspect-Oriented programming (AOP) is a paradigm proposal that retains the advantages of OOP and aims at achieving a better separation of concerns. In this paper we provide an assessment of AOP and we discuss the architecture of an aspect-oriented framework. The goals of our proposal is to achieve an improved separation of concerns in both design, and implementation, to provide adaptability, and to support the complex interaction
In this paper, the performance of turbo coded signals are investigated over a new channel model, denoted as 1/spl plusmn/D/sup n//Partial Response Fading Channels (PRFC) with imperfect phase reference. The combined ef...
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In this paper, the performance of turbo coded signals are investigated over a new channel model, denoted as 1/spl plusmn/D/sup n//Partial Response Fading Channels (PRFC) with imperfect phase reference. The combined effects of the 1/spl plusmn/D/sup n//PRFC and nonideal coherent receiver on the phase of the received amplitude and of a noisy carrier reference are considered. The numerical results demonstrate the error performance degradation due to both amplitude fading and phase noise process.
Let G be a connected graph of n vertices. The problem of finding a depth-first spanning tree of G is to find a connected subgraph of G with the n vertices and n - 1 edges by depth-first-search. In this paper, we propo...
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Nested datatypes generalise regular datatypes in much the same way that context-free languages generalise regular ones. Although the categorical semantics of nested types turns out to be similar to the regular case, t...
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Nested datatypes generalise regular datatypes in much the same way that context-free languages generalise regular ones. Although the categorical semantics of nested types turns out to be similar to the regular case, the fold functions are more limited because they can only describe natural transformations. Practical considerations therefore dictate the introduction of a generalised fold function in which this limitation can be overcome. In the paper we show how to construct generalised folds systematically for each nested datatype, and show that they possess a uniqueness property analogous to that of ordinary folds. As a consequence, generalised folds satisfy fusion properties similar to those developed for regular datatypes. Such properties form the core of an effective calculational theory of inductive datatypes.
A lack of adequate and flexible topology support in the popular message passing systems such as Parallel Virtual Machine was a major factor in the development of our Virtual Process Topology Environment. This parallel...
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