Association and aggregation are two relationship types in the object-oriented conceptual model (OOCM) that frequently involve collection of elements/attributes. However, very often when the relationships are stored in...
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Association and aggregation are two relationship types in the object-oriented conceptual model (OOCM) that frequently involve collection of elements/attributes. However, very often when the relationships are stored in object relational database (ORDB) the collection is flattened like it is implemented by pure relational model. In this paper we propose the mapping methods to preserve the collection semantics in ORDB using collection data type. In aggregation we propose methods for different constraints types, while in association we propose methods for "many" cardinality (I:N, N:N) relationships. In addition, we also show how queries can be performed in the relationships using collection type.
This paper studies complete stability robustness and feedback stabilization problem for uncertain singular systems. New perturbation upper bound that ensures the perturbed singular system remains completely stable (im...
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ISBN:
(纸本)0780388739
This paper studies complete stability robustness and feedback stabilization problem for uncertain singular systems. New perturbation upper bound that ensures the perturbed singular system remains completely stable (impulse-free and asymptotically stable) is derived. Analysis and examples show that the present result is less conservative than the previous ones. Based on an algorithm for eigenstructure assignment, a procedure to construct a state feedback matrix that maximizes the complete stability robustness bound of the closed-loop system is presented.
InfiniBand Architecture (IBA) is a newly established general-purpose interconnect standard applicable to local area, system area and storage area networking and I/O. Networks based on this standard should be capable o...
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InfiniBand Architecture (IBA) is a newly established general-purpose interconnect standard applicable to local area, system area and storage area networking and I/O. Networks based on this standard should be capable of tolerating topological changes due to resource failures, link/switch activations, and/or hot swapping of components. In order to maintain connectivity, the network's routing function may need to be reconfigured on each topological change. Although the architecture has various mechanisms useful for configuring the network, no strategy or procedure is specified for ensuring deadlock freedom during dynamic network reconfiguration. In this paper, a method for applying the Double Scheme over InfiniBand networks is proposed. The Double Scheme provides a systematic way of reconfiguring a network dynamically while ensuring freedom from deadlocks. We show how features and mechanisms available in IBA for other purposes can also be used to implement dynamic network reconfiguration based on the Double Scheme. We also propose new mechanisms that may be considered in future versions of the IBA specification for making dynamic reconfiguration and other subnet management operations more efficient.
The theoretical basis of ray tracing as part of the construction of an approximate solution of Maxwell's equations is discussed. The rays can then be seen as arising as characteristic curves of a partial different...
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The theoretical basis of ray tracing as part of the construction of an approximate solution of Maxwell's equations is discussed. The rays can then be seen as arising as characteristic curves of a partial differential equation for the phase of the wave. If carried through in detail, this approach leads to an additional phase shift that has been discussed previously. Methods of efficiently calculating field strength, Doppler shift, and absorption of the waves are discussed, based on a variational formulation. Some history of the evolution of ionospheric radio ray tracing is given. Numerical and analytic or closed-form ray tracing are contrasted, and guidance is given on the choice of appropriate technique in a particular application. Finally, some suggestions are given for possible useful extensions of the ray-tracing approach.
A framework on web information representation, extraction and derivation utilising the object-oriented approach is proposed in this paper. We define a structure which is similar to a class in object-oriented design an...
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ISBN:
(纸本)0769520731
A framework on web information representation, extraction and derivation utilising the object-oriented approach is proposed in this paper. We define a structure which is similar to a class in object-oriented design and programming, and name it as an extended class (eclass). An eclass contains data attributes, member functions/methods, inference rules and presentations, and therefore, facilities information derivation and web presentation. As an object-oriented approach, the framework also supports encapsulation, polymorphism, composition and inheritance. It can be implemented as an extension of an existing object-oriented programming language. An eclass can be extremely effective in content-dependent entity description. It describes a value under its context, consequently, the search engine not only searches the value, but also understands the meaning of the value in the context. We argue that information in any form or complexity can always be represented by instances of eclasses.
Spamming is a serious issue for the Internet community. As well as incurring financial losses to many organisations, spamming causes mental frustration, and the spam content (much of which includes indecent material) ...
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Spamming is a serious issue for the Internet community. As well as incurring financial losses to many organisations, spamming causes mental frustration, and the spam content (much of which includes indecent material) causes embarrassment and presents moral issues. Many techniques and solutions have been presented over the past few years, but most of them cannot effectively deter the spamming issue totally. The major reason for the failure of these solutions is that spammers use the very protocols used for email transmission and forwarding to flood the network. One reason for the failure of new solutions is the high drop rate of legitimate emails by the receiver entity. Various solutions have been tried to deter spamming, but in vain. Although in theoretical tests these techniques provide an effective defence against the email message flood, the practical implementation of 100% spam protection is still far from reality. We describe a technical solution to prevent end users from receiving spam messages. Although our approach is simple and intuitive, it provides significant resistance against spam attack generation. Rather than countering the spamming at the receiver side,our solution counters the spamming attack at the point of origination, making it a more deterrent solution against spam based attacks.
In this paper we propose an extension to the probabilistic packet marking scheme, for detecting denial-of-service and distributed denial-of-service attacks, using the concept of hidden Markov models. Our approach has ...
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In this paper we propose an extension to the probabilistic packet marking scheme, for detecting denial-of-service and distributed denial-of-service attacks, using the concept of hidden Markov models. Our approach has the potential of probabilistically reconstructing the attacking path from the available packets without the intervention of Internet service providers and without increasing the overhead on the packets.
We present a novel approach to identifying anomalous network events Specifically, a method for characterizing and displaying the flow of conversations across a distributed system with a high number of interacting enti...
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Web services coordination has become a central topic for further development of Internet-based distributed computing. One approach to this coordination task is supported by generative communication, and more specifica...
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