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991.
Sangsan Leelhapantu Thanarat H. Chalidabhongse 《Signal, Image and Video Processing》2018,12(7):1255-1263
Random field formulation has proven to be a powerful framework for solving stereo correspondence problems because of its ability to intuitively incorporate global smoothness constraint with local matching costs. However, solving such problems for cases where large number of pixel variables and possible disparity labels are common can be impractical as the computational complexity grows fast with the number of labels. We proposed a speedup scheme using local label hierarchy in which we exploit characteristics of stereo vision problem to obtain a hierarchical energy minimization technique. In doing so, we give definitions and notations for local label hierarchy as well as approaches for label-wise grouping. We also generalize the definition of energy function to include sets of labels and present heuristics for assigning group potentials. Our approach builds different “local” hierarchy for each variable using information from the energy function which enables us to achieve better performance when compared to using the same hierarchy for every variable. The added processing steps have significantly less theoretical computational complexity than the overall process. Our method was tested with different combinations of cost functions, and our experiment has shown that our heuristics can assist in speeding up the computation time while providing comparable energy and error. 相似文献
992.
提出了一种特殊米波雷达体制下的多目标检测方法。该方法借助数字波束形成(DBF)、脉冲多普勒(PD)和单脉冲技术在空域、时域、频域内完成目标测量。文中给出了系统框图、检测算法和仿真结果 相似文献
993.
Xin Zhang Xu-yi Ma Qing-mei Lu Fei-peng Zhang Yan-qin Liu Jiu-xing Zhang Lei Wang 《Journal of Electronic Materials》2011,40(5):773-777
n-Type thermoelectric powders of (Bi2−x
Ag
x
Te3)0.96−(Bi2Se3)0.04 (0 ≤ x ≤ 0.05) have been synthesized by mechanical alloying and then consolidated by spark plasma sintering. The analysis results
show that the grain size of pure Bi, Te, Ag, and Se powders is decreased to about 1 μm to 0.5 μm after they are mechanically alloyed for 2 h. The power factor of bulk material increases with increasing Ag-doping content,
while the trend for the lattice thermal conductivity is the opposite. Bulk (Bi0.99Ag0.04)2(Te0.96Se0.04)3 after milling for 12 h exhibits a higher power factor, lower thermal conductivity, and thus a higher ZT of 0.74 at 373 K. 相似文献
994.
Previous studies of call admission control (CAC) in mobile communication networks focused on call blocking and call dropping mechanisms. However, achieving global optimization of the system benefit is a complicated process. In this paper, we propose a benefit optimization model that accommodates as many users as possible, while simultaneously maintaining system-wide quality of service (QoS) in terms of admission control. To clarify the CAC concept, we construct a framework of CAC policies, derive associated interference models based on the framework, and then investigate the effects of the policies on the system benefit. In addition, to solve the complicated integer programming problem, we adopt the Lagrangean relaxation approach, and employ Lagrangean multipliers to perform sensitivity analysis of several parameters. The contribution of this study is twofold: the novel problem formulation and the improvement in the system benefit. The computational results demonstrate that the system accrues more benefit as new traffic is loaded and the number of users increases. Meanwhile, the sensitivity analysis shows that proper assignment of the strength of power-controlled signals is a key factor in the global optimization of the system benefit. 相似文献
995.
Yeonsik Jeong Sriram Lakshmanan Sandeep Kakumanu Raghupathy Sivakumar 《Wireless Networks》2011,17(3):567-582
In this paper we present a new approach called cue-based networking that uses hints or cues about the physical environment to optimize networked application behavior. We define the notion of
cues and describe how cues can be obtained using wireless sensor networks as the underlying platform. We identify both the
research and system challenges that need to be addressed to realize benefits of the approach under a target application of
video delivery over IP networks. In the process, we identify key challenges of wireless sensor networks, namely timeliness
and robustness. We design an adaptive algorithm that balances the tradeoff between them satisfying both timeliness and robustness
requirements. Through an implementation of the video delivery application using the proposed algorithm in a real home environment,
we highlight the practical benefits of the proposed approach. 相似文献
996.
Overview of the MPEG Reconfigurable Video Coding Framework 总被引:2,自引:0,他引:2
Shuvra S. Bhattacharyya Johan Eker Jörn W. Janneck Christophe Lucarz Marco Mattavelli Mickaël Raulet 《Journal of Signal Processing Systems》2011,63(2):251-263
Video coding technology in the last 20 years has evolved producing a variety of different and complex algorithms and coding standards. So far the specification of such standards, and of the algorithms that build them, has been done case by case providing monolithic textual and reference software specifications in different forms and programming languages. However, very little attention has been given to provide a specification formalism that explicitly presents common components between standards, and the incremental modifications of such monolithic standards. The MPEG Reconfigurable Video Coding (RVC) framework is a new ISO standard currently under its final stage of standardization, aiming at providing video codec specifications at the level of library components instead of monolithic algorithms. The new concept is to be able to specify a decoder of an existing standard or a completely new configuration that may better satisfy application-specific constraints by selecting standard components from a library of standard coding algorithms. The possibility of dynamic configuration and reconfiguration of codecs also requires new methodologies and new tools for describing the new bitstream syntaxes and the parsers of such new codecs. The RVC framework is based on the usage of a new actor/ dataflow oriented language called CAL for the specification of the standard library and instantiation of the RVC decoder model. This language has been specifically designed for modeling complex signal processing systems. CAL dataflow models expose the intrinsic concurrency of the algorithms by employing the notions of actor programming and dataflow. The paper gives an overview of the concepts and technologies building the standard RVC framework and the non standard tools supporting the RVC model from the instantiation and simulation of the CAL model to software and/or hardware code synthesis. 相似文献
997.
Mobility measurement and degradation mechanisms of MOSFETs made with ultrathin high-k dielectrics 总被引:1,自引:0,他引:1
Accurate measurements and degradation mechanisms of the channel mobility for MOSFETs with HfO/sub 2/ as the gate dielectric have been systematically studied in this paper. The error in mobility extraction caused by a high density of interface traps for a MOSFET with high-k gate dielectric has been analyzed, and a new method to correct this error has been proposed. Other sources of error in mobility extraction, including channel resistance, gate leakage current, and contact resistance for a MOSFET with ultrathin high-k dielectric have also been investigated and reported in this paper. Based on the accurately measured channel mobility, we have analyzed the degradation mechanisms of channel mobility for a MOSFET with HfO/sub 2/ as the gate dielectric. The mobility degradation due to Coulomb scattering arising from interface trapped charges, and that due to remote soft optical phonon scattering are discussed. 相似文献
998.
999.
Optical add/drop multiplexers (OADMs) can significantly reduce the cost of metro optical wavelength-division multiplexing
(WDM) ring networks by allowing traffic to bypass intermediate nodes without expensive opto-electro-opto (O-E-O) conversion.
Some traditional OADMs, called fixed OADMs (FOADMs), can only add/drop traffic on a specific wavelength. Reconfigurable Optical
Add/Drop Multiplexers (ROADMs) are emerging, which can add/drop traffic onto/from different wavelengths at different time.
ROADMs provide desirable flexibility, enable fast provisioning of dynamic traffic, and save capital expenditure (CapEx) and
operational expenditure (OpEx). In order to be cost-effective, some ROADMs employ architectures that tune the ROADM continuously
from one wavelength to another, crossing through all the wavelengths in-between, which may cause interference to the connections,
if any, on those wavelengths being crossed. In order to prevent existing connections from being interrupted, a constraint
needs to be imposed that ROADMs cannot cross working wavelengths when tuning. In this study, the design and the benefits of
metro optical WDM network architectures using ROADMs and the impact of this tuning constraint on the performance of the network
are investigated. Mathematical formulation of the problem of provisioning of connections with advance reservation, in which
the arrival time and departure time of all the connections are known in advance, is presented, and results for a small network
are shown. 相似文献
1000.
The paper presents a routing algorithm that maximizes the lifetime of a sensor network in which all data packets are destined
for a single collection node. Lifetime is maximized by adjusting the number of packets traversing each node. The adjustment
is carried out by transmitting over alternative routes. The first part of the paper assumes that the worst case delay resulting
from energy efficient routing is less than the maximum tolerable value. Ignoring the delay constraint of the network, the
routes are selected as the solution to a linear programming (LP) problem in which the objective is to maximize the minimum
lifetime of each node. The solution is implemented in a centralized algorithm, and then approximated by an iterative algorithm
based on least cost path routing, in which each step is implemented efficiently in a distributed manner. The second part of
the paper incorporates delay guarantee into energy efficient routing by constraining the length of the routing paths from
each sensor node to the collection node. Simulations reveal that the lifetime of the network increases significantly by optimal
routing, and including delay constraint in energy efficient routing improves the network performance since the delay of the
network keeps increasing as the delay constraint is relaxed beyond the value at which the optimal lifetime is achieved.
Research supported by National Science Foundation under Grant CMS-0408627 and California Department of Transportation.
Sinem Coleri Ergen received the BS degree in electrical and electronics engineering from Bilkent University, Ankara, Turkey, in 2000, and the
M.S. and Ph.D. degrees in electrical engineering and computer sciences from University of California Berkeley (UCB), in 2002
and 2005. Since January 2006, she has been a postdoctoral researcher in electrical engineering at UCB. Her research interests
are in wireless communications and networking with a current focus on energy efficient system design for sensor networks.
She is a member of the Sensor Networks for Traffic Monitoring project at UCB. She received Regents Fellowship from University
of California Berkeley in 2000.
Pravin Varaiya is Nortel Networks Distinguished Professor in the Department of Electrical Engineering and Computer Sciences at the University
of California, Berkeley. From 1975 to 1992 he was also Professor of Economics at Berkeley. From 1994 to 1997 he was Director
of the California PATH program, a multi-university research program dedicated to the solution of Californias transportation
problems. His current research is concerned with communication networks, transportation, and hybrid systems. He has taught
at MIT and the Federal University of Rio de Janeiro. Varaiya has held a Guggenheim Fellowship and a Miller Research Professorship.
He received an Honorary Doctorate from LInstitut National Polytechnique de Toulouse, and the Field Medal of the IEEE Control
Systems Society. He is a Fellow of IEEE and a member of the National Academy of Engineering. He is on the editorial board
of several journals, including “Discrete Event Dynamical Systems” and “Transportation Research—C”. He has co-authored three
books and more than 250 technical papers. The second edition of “High-Performance Communication Networks” (with Jean Walrand)
was published by Morgan-Kaufmann in 2000. “Structure and interpretation of signals and systems" (with Edward Lee) was published
by Addison-Wesley in 2003. Varaiya is a member of the Board of Directors of Sensys Networks. 相似文献