Computational results for the microwave heating patterns in singlefed multimode empty and loaded cavities are presented in this paper. Combined Finite Difference Time Domain (FDTD) and Finite Volume (FV) methods are u...
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ISBN:
(纸本)9781581138122
Computational results for the microwave heating patterns in singlefed multimode empty and loaded cavities are presented in this paper. Combined Finite Difference Time Domain (FDTD) and Finite Volume (FV) methods are used to solve the equations that describe the electromagnetic field and heat transfer in the processed samples, The coupling between the two schemes is through a change in dielectric properties which are assumed to be temperature dependent. The model takes into account the changing effect of the load's properties on the electric field and modal patterns. A study of the modes and their corresponding field pattern inside a resonant cavity is presented computationally using the FDTD solver. The coupled algorithm is then used to investigate heat distribution by observing the occurrence of resonant conditions which are responsible for achieving high heating levels.
This paper presents a simulation framework for UML models based upon a mapping schema of UML metamodel elements into Abstract State Machines (ASMs). Structural model elements are translated into an ASM vocabulary as c...
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This paper presents a simulation framework for UML models based upon a mapping schema of UML metamodel elements into Abstract State Machines (ASMs). Structural model elements are translated into an ASM vocabulary as collections of domains and functions, whereas the dynamic view is captured by multi-agent ASMs reflecting the behavior modeled by UML state machines. In the toolkit presented, input UML models can be drawn using any UML CASE Tool able to produce the XMI format for diagrams. This textual representation is exploited to initialize the ASM model for UML state machines which can be symbolically executed by AsmGofer, an advanced Abstract State Machine programming system. Tool features are described through the simulation of a simple stack-printer UML model showing the interactions among state machines by signals exchange and operation calls.
A data warehouse (DW) provides an information for analytical processing, decision making, and data mining tools. On the one hand, the structure and content of a data warehouse reflects a real world, i.e. data stored i...
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A data warehouse (DW) provides an information for analytical processing, decision making, and data mining tools. On the one hand, the structure and content of a data warehouse reflects a real world, i.e. data stored in a DW come from real production systems. On the other hand, a DW and its tools may be used for predicting trends and simulating a virtual business scenarios. This activity is often called the what-if analysis. Traditional DW systems have static structure of their schemas and relationships between data, and therefore they are not able to support any dynamics in their structure and content. For these purposes, multiversion data warehouses seem to be very promising. In this paper we present a concept and an ongoing implementation of a multiversion data warehouse that is capable of handling changes in the structure of its schema as well as simulating alternative business scenarios.
This work presents the idea and a prototype of workflow systems whose definition is based on constraints. The flexibility is reached through the less rigid definition of workflow definitions - the workflow is defined ...
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This work presents the idea and a prototype of workflow systems whose definition is based on constraints. The flexibility is reached through the less rigid definition of workflow definitions - the workflow is defined as a set of pre and post conditions of activities, which are selected dynamically as the process instance unfolds. The workflow system besides dispatching activities that have all their preconditions fulfilled to be executed, also helps users to decide which activity to chose through what if scenarios. The system also includes an access control model which not only represents which users have the authority to chose and execute the activities but also the authority to override the constraints. In particular, overriding constraints is itself an activity and thus may have pre and post conditions defined in other constraints. The paper present Tucupi, a prototype of such constraint based WFMS.
We present an efficient and practical lock-free implementation of a concurrent dictionary that is suitable for both fully concurrent (large multi-processor) systems as well as pre-emptive (multi-process) systems. Many...
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ISBN:
(纸本)9781581138122
We present an efficient and practical lock-free implementation of a concurrent dictionary that is suitable for both fully concurrent (large multi-processor) systems as well as pre-emptive (multi-process) systems. Many algorithms for concurrent dictionaries are based on mutual exclusion. However, mutual exclusion causes blocking which has several drawbacks and degrades the system's overall performance. Non-blocking algorithms avoid blocking, and are either lock-free or wait-free. Our algorithm is based on the randomized sequential list structure called Skiplist, and implements the full set of operations on a dictionary that is suitable for practical settings. In our performance evaluation we compare our algorithm with the most efficient non-blocking implementation of dictionaries known. The experimental results clearly show that our algorithm outperforms the other lock-free algorithm for dictionaries with realistic sizes, both on fully concurrent as well as pre-emptive systems.
Protein threading programs align a probe amino acid sequence onto a library of representative folds of known protein structure to identify a structural homology. A scoring function is usually formulated in terms of th...
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ISBN:
(纸本)9781581138122
Protein threading programs align a probe amino acid sequence onto a library of representative folds of known protein structure to identify a structural homology. A scoring function is usually formulated in terms of the threading energy to evaluate protein sequence-structure fitness. The structure that yields the lowest total energy is considered the leading template of the probe protein. An alternative approach is to predict the probabilities of observing amino acid side-chains in structural environment without considering the energy of contacts. In this paper, a model named TES is proposed on building a new environment-specific protein sequence-structure mapping with artificial neural network. The decoy sets obtained from the web are used to test the proposed TES method on discrimination of native and decoy protein three-dimensional structure. The verified approach shows that the performance of the proposed method is comparable to those of knowledge-based potential energy function.
We present a programming notation aiming at protecting the secrecy of both host and agent data in global computing applications. The approach exploits annotations with sets of node addresses, called regions. A datum c...
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ISBN:
(纸本)9781581138122
We present a programming notation aiming at protecting the secrecy of both host and agent data in global computing applications. The approach exploits annotations with sets of node addresses, called regions. A datum can be annotated with a region that specifies the network nodes that are allowed to interact with it. Network nodes come equipped with two region annotations specifying the nodes that can send data and spawn processes over them. The language semantics guarantees that computation proceeds according to these region constraints. To minimize the overhead of runtime checks, a static compilation phase is exploited. The proposed approach is largely independent of a specific programming language;however, to put it in concrete form, here we focus on its integration within the process language μKLAIM. We prove that in compiled μKLAIM nets, data can be manipulated only by authorized users. We also give a more local formulation of this property, where only a subnet is compiled. Finally, we use our theory to model the secure behaviour of a UNIX-like multiuser system.
Despite the widespread use and adoption of cookies as the basis for web applications to keep state information, cookies present some design issues that are yet to be fully addressed. The fact that cookies are stored o...
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Despite the widespread use and adoption of cookies as the basis for web applications to keep state information, cookies present some design issues that are yet to be fully addressed. The fact that cookies are stored on client-side's memory means that they are tightly coupled to the machine that is interacting with the web server. Yet often, these cookies are initiated by web applications to identify user's preferences and identifications. As the user moves across different machines to access the same site, the information previously recorded is lost and the web application has no way of restoring the state, unless the user revisits the same client machine, where the original cookies were set. This paper presents a novel solution to address the need for cookies to be "mobile" by leveraging on smart card to manage cookies, with the benefit of mobility in a pocket. We describe the design and implementation of the CookiesCard framework that uses smart card as a secure and mobile storage media to manage personalized cookies, The article presents the development of the CookiesCard proxy that directly interacts with the smart card to provide cookies management, while acting as an intermediatary between the client browser and a web server.
Web applications are vulnerable to failures and low performance due to the large population of users and the widespread distribution of Internet. Transaction technology provides Web applications with high reliability ...
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ISBN:
(纸本)9781581138122
Web applications are vulnerable to failures and low performance due to the large population of users and the widespread distribution of Internet. Transaction technology provides Web applications with high reliability and improved performance. This paper presents a novel approach for the efficient commit processing of Web transactions. The proposed approach is based on the implementation of priority active network scheduling mechanism at each network node. It involves rigorous analysis of a network node with finite capacity to accommodate messages, bursty arrival process to represent incoming multi-class messages, and the employment of a priority scheduling mechanism to give preferential treatment to high priority messages. This analytical solution provides closed form expressions for calculating the queuing delay per class involved in the commit processing of Web transactions at each network node. The proposed approach significantly reduces the queuing delay for high priority messages such as commit, abort, and compensation of Web transactions. Consequently, performance of the commit processing of Web transactions is improved as response time of the nodes responsible for making decision is reduced.
A number of asymmetrical payment methods have been developed to enable mobile users to buy goods online by charging them to their mobile phone bills by their network operators. It has been recognized that these method...
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A number of asymmetrical payment methods have been developed to enable mobile users to buy goods online by charging them to their mobile phone bills by their network operators. It has been recognized that these methods must be used in conjunction with the security services of authentication and non-repudiation of the origin of the request(s) sent from a mobile user so as to prevent fraudulent actions by the network operator or any other entities. This paper presents a novel joint-signature scheme that can be used as one of the security primitives to address the above security services. The scheme enables a mobile user to securely and efficiently instruct his/er network operator for m-payment related actions. It is based on the use of the one-way hash function and traditional digital signature method, but in a collaborative manner with the network operator. The joint-signature scheme achieves the same security services as those by a traditional digital signature scheme, i.e. message origin authentication, message integrity and non-repudiation of origin, but offers lower computational cost for the mobile user. In addition, it imposes lower communication cost in comparison with proxy/server-aided signature schemes.
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