8,122 research outputs found
Magnetic and axial-vector transitions of the baryon antidecuplet
We report the recent results of the magnetic transitions and axial-vector
transitions of the baryon antidecuplet within the framework of the chiral
quark-soliton model. The dynamical model parameters are fixed by experimental
data for the magnetic moments of the baryon octet, for the hyperon semileptonic
decay constants, and for the singlet axial-vector constant. The transition
magnetic moments and are well reproduced
and other octet-decuplet and octet-antidecuplet transitions are predicted. In
particular, the present calculation of is found to be
below the upper bound that the SELEX collaboration measured very
recently. The results explains consistently the recent findings of a new
resonance from the GRAAL and Tohoku LNS group. We also obtain the transition
axial-vector constants for the from which the decay width of
the pentaquark baryon is determined as a function of the
pion-nucleon sigma term . We investigate the dependence of the
decay width of the on the , with the
varied within the range of the experimental uncertainty. We show that a small
decay width of the , i.e. MeV, is
compatible with the values of all known semileptonic decays with the generally
accepted value of for the proton.Comment: 8 pages, 5 figures, Talk given at the Yukawa International Seminar
(YKIS) 2006, "New frontiers in QCD", Kyoto, Japan, 20 Nov. - 8 Dec. 200
Energy management system and pervasive service-oriented networks
In this work, we study the energy management system (EMS) in the customer domain of the Smart Grid. We discuss the desired features and design issues, highlight the characteristics and identify the challenges. To address the challenges, we propose the innovative framework of Pervasive Service-Oriented Networks (PERSON). The core idea is to utilize a heterogeneous network as the information infrastructure, abstract the functionalities into services, and deploy context-aware intelligence to address the system dynamics. Furthermore, based on the framework of PERSON, we implement a powerful yet cost-effective EMS. The effectiveness of the EMS is demonstrated by a demand response application. ©2010 IEEE.published_or_final_versionThe 1st IEEE International Conference on Smart Grid Communications (SmartGridComm 2010), Gaithersburg, MD., 4-6 October 2010. In Proceedings of the 1st SmartGridComm, 2010, p. 1-
Magnetic moments of exotic pentaquark baryons
In this talk, we present our recent investigation on the magnetic moments of
the exotic pentaquark states, based on the chiral quark-soliton model, all
relevant intrinsic parameters being fixed by using empirical data.Comment: 5 pages, 1 figure, a talk presented at the 10th International
Conference on Baryons (Baryons04), Palaiseau, October 25-29, 200
Hybrid cargo-level tracking system for logistics
In this paper, we propose a hybrid cargo-level tracking system for logistics. We highlight the special system requirements, discuss the design issues and identify the design principles. Then we propose an innovative hybrid system. As far as we know, this is the first system that exploits both infrastructure-based and infrastructure-less positioning schemes for practical cargo-level tracking. Compared with existing systems, the proposed system provides a ubiquitous cargo-level tracking solution with enhanced availability, reliability, and lower total costs. © 2010 IEEE.published_or_final_versionThe 71st IEEE Vehicular Technology Conference (VTC2010-Spring), Taipei, Taiwan, 16-19 May 2010. In Proceedings of 71st IEEE-VTC (Spring), 2010, p. 1-
Adaptive video transmission for OFDMA systems
An adaptive framework is proposed for multi-user video transmission over orthogonal frequency division multiple access (OFDMA) systems. Utilizing the channel knowledge, a two-step heuristic sub-carrier assignment algorithm is proposed to achieve unequal error protection for the video data. The approach also solves the fairness issue among different users that may be caused by varying channel quality on different sub-carriers. Meanwhile, multi-user channel gain is also achieved. The proposed framework significantly improves the video transmission quality with little extra computational complexity and system overhead. ©2007 IEEE.published_or_final_versio
Adaptive sub-channel allocation based UEP for video transmission in space-time coded OFDM systems
In this work, we introduce the idea of adaptive sub-channel allocation based unequal error protection (ASCA-UEP) to a space-time block coded orthogonal frequency division multiplexing (STBC-OFDM) system. In such a system, UEP is realized by adaptively allocating and transmitting high-priority and low-priority video data over high-quality and low-quality sub-channels, respectively. Further, we propose two ASCA-UEP schemes in a time division duplex (TDD) system: a receiver-based scheme and a transmitter-based scheme. Analysis and simulation results demonstrate that ASCA-UEP greatly enhances the quality of video reception, and the transmitter-based scheme is more robust to uplink channel noise than the receiver-based scheme, and is thus preferred when the receiver is power-constrained and the transmitter has sufficient power.published_or_final_versio
Unequal error protection for MIMO systems with a hybrid structure
We propose a hybrid multiple-input-multiple-output (MIMO) architecture to implement unequal error protection (UEP) for video delivery in MIMO systems. On the transmitter side, some of the transmit antennas are used to implement transmit diversity for delivering video data with high priority, while others are employed for spatial multiplexing to transmit video data with low priority. On the receiver side, a hybrid signal detection mechanism is adopted to separate and decode the mixed data. The goal is to exploit the diversity gain to provide better protection to the high priority data, while transmitting the low priority data with spatial multiplexing to achieve high data rate. Analysis and simulation results demonstrate that the proposed UEP mechanism significantly enhances the quality of video reception with a high spectrum efficiency. © 2006 IEEE.published_or_final_versio
Reliable H ∞ control for affine nonlinear systems
This paper addresses the reliable H ∞-control problems for affine nonlinear systems. Based on the Hamilton-Jacobi inequality approach developed in the H ∞-control problems for affine nonlinear systems, a method for the design of reliable nonlinear control systems is presented. The resulting nonlinear control systems are reliable in that they provide guaranteed local asymptotic stability and H ∞ performance not only when all control components are operational, but also in the case of some component outages within a prespecified subset of control components. A numerical example is also given.published_or_final_versio
Blind symbol synchronization based on cyclic prefix for OFDM systems
In this paper, a blind symbol synchronization algorithm is presented for orthogonal frequency-division multiplexing (OFDM) systems, and a new timing function based on the redundancy of the cyclic prefix (CP) is introduced. It proves that the maximum of this function necessarily points to the correct timing offset, irrespective of channel conditions when the signal-to-noise ratio is high. Using the timing function, the timing offset is estimated through a searching algorithm. Channel power profile and channel length information are unnecessary. Simulation results show that the proposed algorithm is robust and outperforms the existing CP-based algorithms, particularly in frequency-selective fading channels. © 2008 IEEE.published_or_final_versio
Detecting dynamic communities in opportunistic networks
In opportunistic networks, communities of mobile entities may be utilized to improve the efficiency of message forwarding. However, identifying communities that are dynamically changing in mobile environment is non-trivial. Based on random walk on graphs, in this paper we present a community detection algorithm that takes into account the aging and weight of contacts between mobile entities. Our idea originates from message-forwarding operations in opportunistic networks. We evaluate the algorithm on both computer-generated networks and real-world human mobility traces. The result shows that our proposed algorithm can find the communities and detect the changes in their structures over time. © 2009 IEEE.published_or_final_versionThe 1st International Conference on Ubiquitous and Future Networks (ICUFN 2009), Hong Kong, China, 7-9 June 2009. In Proceedings of the 1st ICUFN, 2009, p. 159-16
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