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Communication Scheme (communication + scheme)

Distribution by Scientific Domains
Engineering42%

Selected Abstracts

A digital secure image communication scheme based on the chaotic Chebyshev map

INTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 5 2004
Xiaofeng Liao
Abstract In this paper, a simple image secure communication scheme based on the chaotic Chebyshev map and chaos synchronization is proposed. The scheme relies on the excellent correlation property of chaotic sequences, which is very desirable for secure image communication. The results obtained by computer simulation indicate that the transmitted source image can be correctly and reliably recovered using the proposed scheme, even through a noisy channel. Notably, the scheme possesses relatively high security and can be easily implemented. Moreover, the quality of the recovered image is satisfactory, quantified by such common criteria as the bit-error rate performance. Copyright © 2004 John Wiley & Sons, Ltd. [source]

A scheme for solving Anycast scalability in IPv6

INTERNATIONAL JOURNAL OF NETWORK MANAGEMENT, Issue 4 2008
Wang Xiaonan
The existing designs for providing Anycast services are either to confine Anycast groups to a preconfigured topological region or to distribute Anycast groups globally across the whole Internet. The latter causes routing tables to grow proportionally to the number of global Anycast groups in the entire Internet and both of the above designs restrict and hinder the application and development of Anycast services. A new kind of Anycast communication scheme is proposed in this paper. This scheme adopts a novel Anycast address structure which can achieve a dynamic Anycast group while allowing Anycast members to freely leave and join the Anycast group without geographical restriction and it effectively solves the expanding explosion of the Anycast routing table. In addition, this scheme can evenly disperse Anycast request messages from clients across the Anycast servers of one Anycast group, thus achieving load balance. This paper analyzes the communication scheme in depth and discusses its feasibility and validity. The experimental data in IPv6 simulation demonstrate that the TRT (Total Response Time) of one Anycast service (e.g., file downloading) acquired through this communication scheme is shorter by 15% than that through the existing Anycast communication scheme. Copyright © 2007 John Wiley & Sons, Ltd. [source]

Self-heterodyne diode mixer with GCPW using thin film process at 60 GHz

MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 1 2009
Seung-Woon Choi
Abstract A self-heterodyne diode mixer is proposed using thin film process based on alumina substrate at 60 GHz in conjunction with grounded coplanar waveguide transition. To down-convert both very low RF and LO signals received simultaneously from transmitter for self-heterodyne communication scheme, the proposed mixer adapted with the knee voltage bias condition of 0.65 [V] improves its mixing efficiency significantly. The designed SHM shows the conversion loss of ,15.13 dB at RF and LO frequencies of 60.565 and 59.01 GHz, respectively, with both input powers of ,15 dBm and it also can defines IMD free input dynamic range as ,30 dBm. The measured return losses satisfies with more than 20 dB and 9 dB for RF/LO input and IF output port, respectively. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 13,15, 2009; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23959 [source]

Vertex disjoint routings of cycles over tori

NETWORKS: AN INTERNATIONAL JOURNAL, Issue 3 2007
Jean-Claude Bermond
Abstract We study the problem of designing a survivable WDM network based on covering the communication requests with subnetworks that are protected independently from each other. We consider here the case when the physical network is T(n), a torus of size n by n, the subnetworks are cycles and the communication scheme is all-to-all or total exchange (where all pairs of vertices communicate). We will represent the communication requests by a logical graph: a complete graph for the scheme of all-to-all. This problem can be modeled as follows: find a cycle partition or covering of the request edges of K, such that for each cycle in the partition, its request edges can be routed in the physical network T(n) by a set of vertex disjoint paths (equivalently, the routings with the request cycle form an elementary cycle in T(n)). Let the load of an edge of the WDM network be the number of paths associated with the requests using the edge. The cost of the network depends on the total load (the cost of transmission) and the maximum load (the cost of equipment). To minimize these costs, we will search for an optimal (or quasi optimal) routing satisfying the following two conditions: (a) each request edge is routed by a shortest path over T(n), and (b) the load of each physical edge resulting from the routing of all cycles of S is uniform or quasi uniform. In this article, we find a covering or partition of the request edges of K into cycles with an associated optimal or quasi optimal routing such that either (1) the number of cycles of the covering is minimum, or (2) the cycles have size 3 or 4. © 2007 Wiley Periodicals, Inc. NETWORKS, Vol. 49(3), 217,225 2007 [source]

Multiphoton entanglement and interferometry

FORTSCHRITTE DER PHYSIK/PROGRESS OF PHYSICS, Issue 4-5 2003
M. Bourennane
Multiphoton entanglement is the basis of many quantum communication schemes, quantum cryptographic protocols, and fundamental tests of quantum theory. Spontaneous parametric down-conversion is the most effective source for polarization entangled photon pairs. Here we show, that a class of entangled 4-photon states can be directly created by parametric down-conversion. These states exhibit perfect quantum correlations and a high robustness of entanglement against photon loss. Therefore these states are well suited for new types of quantum communication. [source]