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Interaction-free all-optical switching via the quantum Zeno effect

Physical Review A 2010年第6期82卷 063826-063826页

作者： Yu-Ping Huang Joseph B. Altepeter Prem Kumar Center for Photonic Communication and Computing Department of Electrical Engineering and Computer Science Northwestern University 2145 Sheridan Road Evanston Illinois 60208-3118 USA

We propose an interaction-free scheme for all-optical switching which does not rely on the physical coupling between signal and control waves. The interaction-free nature of the scheme allows it to overcome the fundamental photon-loss limit imposed by the signal-pump coupling. The same phenomenon protects photonic-signal states from decoherence, making devices based on this scheme suitable for quantum applications. Focusing on χ(2) waveguides, we provide device designs for traveling-wave and Fabry-Perot switches. In both designs, the performance is optimal when the signal switching is induced by coherent dynamical evolution. In contrast, when the switching is induced by a rapid dissipation channel, it is less efficient.

关键词： Switching

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Friendship Based Routing in Delay Tolerant Mobile Social Networks

Friendship Based Routing in Delay Tolerant Mobile Social Net...

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2010 IEEE Global Telecommunications Conference GLOBECOM 2010

作者： Eyuphan Bulut Boleslaw K. Szymanski Department of Computer Science and Center of Pervasive Computing and Networking Rensselaer Polytechnic Institute Troy NY USA

Routing in delay tolerant networks (DTN) have attracted a great interest recently. Increasingly popular type of DTNs are mobile social networks (MSN) also called pocket switched networks. Hence, analyzing accurately social network properties has become an important issue in designing efficient routing protocols for MSNs. In this paper, we first introduce a new metric for detecting the quality of friendships accurately. Using the introduced metric, each node defines its friendship community as the set of nodes having close friendship with itself either directly or indirectly. Then, we present Friendship Based Routing in which temporally differentiated friendships are used to make the forwarding decisions of messages. Real trace-driven simulation results show that the introduced algorithm achieves better delivery rate while forwarding fewer messages than the existing algorithms.

关键词： Peer to peer computing Routing Communities Social network services Delay Mobile computing

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Evaluation of extended error taxonomy for OWL2

Evaluation of extended error taxonomy for OWL2

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International Conference on Information and Emerging Technologies, ICIET

作者： Naseer Ahmed Sajid Muhammad Abdul Qadir Tariq Ali Center for Distributed and Semantic Computing Department of Computer Science Mohammad Ali Jinnah University Islamabad Pakistan

Ontology Evaluation is one of the most critical phases in ontology engineering. Applications depending upon ontology can have serious and appalling problems if ontology itself is infected with errors. Therefore, ontology should be consistent, complete and errors free. An error taxonomy using OWL constructs and axioms was developed to overcome the possibility of occurring errors in ontology. Recently, some new features have been proposed in OWL2 specification to overcome the limitation of expressive power of OWL. In this paper we evaluate the extended error taxonomy of OWL with the new features of OWL2. We also evaluate that while using OWL2 features, occurrence of possibility of new types of errors get reduced or not. On the basis of different examples for each error, we conclude that the error taxonomy is also valid for OWL2. This is because of the fact that every OWL ontology is a valid OWL2 ontology and every OWL2 ontology (excluding new features) is also a valid OWL ontology. The zero level circulatory errors can also be removed if we use the reflexive property and self restriction (local reflexive) property of OWL2. Otherwise, we have to generate a warning omission for zero level circulatory error.

关键词： Ontologies Taxonomy Redundancy OWL Semantics Animals Vocabulary

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PCFG Based Synthetic Mobility Trace Generation

PCFG Based Synthetic Mobility Trace Generation

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2010 IEEE Global Telecommunications Conference GLOBECOM 2010

作者： Sahin Cem Geyik Eyuphan Bulut Boleslaw K. Szymanski Department of Computer Science and Center of Pervasive Computing and Networking Rensselaer Polytechnic Institute Troy NY USA

This paper introduces a novel method of generating mobility traces based on Probabilistic Context Free Grammars (PCFGs). A PCFG is a generalization of a context free grammar in which each production rule is augmented with a probability with which this production is applied during sentence generation. A concise PCFG can be inferred from the given real world trace collected from the actual mobile node behaviors. The resulting grammar can be used to generate sequences of arbitrary length mimicking the mobile node behavior. This is important when new protocol designs for mobile networks are tested by simulation. In the paper, we describe the methods developed to construct such grammars from training data (mobility history). We also discuss how to generate the synthetic data with an already constructed grammar. We present the experimental results on two real data sets, measuring similarity of the actual traces with the synthetic ones. We compare our grammar based method to a 2-level Markov Model based trace generation method. The results demonstrate that the grammar based approach works as an excellent compression method for the actual data. On many metrics, the synthetic data generated from the PCFG match the training data much better than the one generated by the Markov Model.

关键词： Markov processes Mobile communication Grammar Solid modeling Computational modeling Mobile computing Peer to peer computing

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Conditional shortest path routing in delay tolerant networks

Conditional shortest path routing in delay tolerant networks

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IEEE International Symposium on World of Wireless Mobile and Multimedia Networks (WoWMoM)

作者： Eyuphan Bulut Sahin Cem Geyik Boleslaw K. Szymanski Department of Computer Science and Center of Pervasive Computing and Networking Rensselaer Polytechnic Institute Troy NY USA

Delay tolerant networks are characterized by the sporadic connectivity between their nodes and therefore the lack of stable end-to-end paths from source to destination. Since the future node connections are mostly unknown in these networks, opportunistic forwarding is used to deliver messages. However, making effective forwarding decisions using only the network characteristics (i.e. average intermeeting time between nodes) extracted from contact history is a challenging problem. Based on the observations about human mobility traces and the findings of previous work, we introduce a new metric called conditional intermeeting time, which computes the average intermeeting time between two nodes relative to a meeting with a third node using only the local knowledge of the past contacts. We then look at the effects of the proposed metric on the shortest path based routing designed for delay tolerant networks. We propose Conditional Shortest Path Routing (CSPR) protocol that routes the messages over conditional shortest paths in which the cost of links between nodes is defined by conditional intermeeting times rather than the conventional intermeeting times. Through trace-driven simulations, we demonstrate that CSPR achieves higher delivery rate and lower end-to-end delay compared to the shortest path based routing protocols that use the conventional intermeeting time as the link metric.

关键词： Routing Delay History Routing protocols Government

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Translation of relational queries into Description Logic for semantic cache query processing

Translation of relational queries into Description Logic for...

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International Conference on Information and Emerging Technologies, ICIET

作者： Tariq Ali Muhammad Abdul Qadir Munir Ahmad Center for Distribute and semantic computing Department of Computer Science Mohammad Ali Jinnah University Islamabad Pakistan

Formulation of efficient algorithms to check implication and satisfibality for relational queries is an important research issue. Implication and satisfibality checking can be used to find query containment in semantic cache query processing and other similar applications. Description logic (DL) is a formalism used to model knowledge of a domain in the form of concepts and a rich set of associations between these concepts in the T-Boxes. Reasoning on these knowledge bases can be performed in order to find explicit relation as well as discover implicit relations. Sound and Complete subsumption algorithms exist for reasoning facts represented in Description Logic. The most common reasoning (which can be used for other sort of reasoning, too) is the determination of a subsumption relation between the logical expressions of T-boxes. In this paper, we propose an algorithm to translate relational queries in to description logic ALC(D), so that DL subsumption algorithms can be applied on these translated queries to find query containment. Working of the algorithm is demonstrated with the help of a case study. Conversion of relational query into DL will also help in optimization of cache size for the storage of semantics by eliminating redundant semantics in the cache. Hence, the sound and complete reasoning services of DL can be used for relational query containment.

关键词： Semantics Cognition Query processing Inference algorithms Servers Concrete Algorithm design and analysis

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Bit-Interleaved Coded Multiple Beamforming with Constellation Precoding

Bit-Interleaved Coded Multiple Beamforming with Constellatio...

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IEEE International Conference on Communications (ICC)

作者： H. J. Park E. Ayanoglu Center of Pervasive Communications and Computing Department of Electrical Engineering and Computer Science University of California Irvine USA

In this paper, we present the diversity order analysis of bit-interleaved coded multiple beamforming (BICMB) combined with the constellation precoding scheme. Multiple beamforming is realized by singular value decomposition of the channel matrix which is assumed to be perfectly known to the transmitter as well as the receiver. Previously, BICMB is known to have a diversity order bound related with the product of the code rate and the number of parallel subchannels, losing the full diversity order in some cases. In this paper, we show that BICMB combined with the constellation precoder and maximum likelihood detection achieves the full diversity order. We also provide simulation results that match the analysis.

关键词： Interleaved codes Array signal processing Analytical models Singular value decomposition Transmitters Bit error rate Communications Society Peer to peer computing Pervasive computing Cultural differences

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Cost Efficient Erasure Coding based Routing in Delay Tolerant Networks

Cost Efficient Erasure Coding based Routing in Delay Toleran...

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IEEE International Conference on Communications

作者： Eyuphan Bulut Zijian Wang Boleslaw K. Szymanski Department of Computer Science and Center of Pervasive Computing and Networking Rensselaer Polytechnic Institute Troy NY USA

Routing in delay tolerant networks (DTNs) in which most of the nodes are mobile and intermittently connected is a challenging problem because of unpredictable node movements and lack of knowledge of future node connections. To ensure reliability against failures and increase the success rate of delivery, erasure coding technique is used to route messages in DTNs. In this paper, we study how the cost of erasure coding based routing protocols can be reduced. Specifically, we analyze the effects of different spraying algorithms, right parameter selection and splitting spraying phase on the cost of message delivery. We also perform simulations to evaluate the proposed approaches and demonstrate that the cost of erasure coding based routing can be reduced considerably with the proposed strategies while maintaining the delivery rate and delay objectives.

关键词： Costs Routing Disruption tolerant networking Peer to peer computing Tornadoes Spraying Delay US Government Communications Society computer science

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Behavior modeling with probabilistic context free grammars

Behavior modeling with probabilistic context free grammars

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International Conference on Information Fusion

作者： Sahin Cem Geyik Jierui Xie Boleslaw K. Szymanski Department of Computer Science and Center of Pervasive Computing and Networking Rensselaer Polytechnic Institute Troy NY USA

Identifying the behavioral patterns in a social network setting is beneficial to understand how people behave in certain application domains. Such patterns can also be utilized to characterize social signals such as social roles from interactions. In this work, we examine how probabilistic context free grammars (PCFGs) can be utilized to model interactions and role taking in a social network. We describe how to automatically build a PCFG given a set of interactions as the training data. Our experiments on the Mission Survival Corpus 1 (MSC-1) dataset show that PCFGs are a concise way of modeling social entity behaviors and are useful in understanding the probability distribution of interactions as well as the behavior types that are observed.

关键词： Grammar Context Measurement Production Probabilistic logic Training data Social network services

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An Upper Bound to the Marginal PDF of the Ordered Eigenvalues of Wishart Matrices and Its Application to MIMO Diversity Analysis

An Upper Bound to the Marginal PDF of the Ordered Eigenvalue...

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IEEE International Conference on Communications (ICC)

作者： H. J. Park E. Ayanoglu Center of Pervasive Communications and Computing Department of Electrical Engineering and Computer Science University of California Irvine USA

Diversity analysis of a number of multiple-input multiple-output (MIMO) applications requires the calculation of the expectation of a function whose variables are the ordered multiple eigenvalues of the Wishart matrices. To solve this, we need the marginal pdf of an arbitrary subset of the ordered eigenvalues. The marginal pdf shown in the literature is useful in numerical analysis, but not beneficial to diversity analysis. In this paper, we derive an upper bound to the marginal pdf of the eigenvalues. The derivation is based on the multiple integration of the well-known joint pdf, which is very complicated due to the exponential factors of the joint pdf. We suggest an alternative function that provides simpler calculation of the multiple integration. As a result, the marginal pdf is shown to consist of a multivariate polynomial with a given degree. By applying the marginal pdf to the calculation of the expectation, the diversity order for a number of MIMO systems can be calculated. Simulation results that support the analysis are presented.

关键词： Upper bound Eigenvalues and eigenfunctions MIMO Matrix decomposition Array signal processing Application software Numerical analysis Polynomials Analytical models Performance analysis

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