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Search Results: 1 - 10 of 268988 matches for " Li B "
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Wireless Hybrid QoS Architecture with an Enhancement of Fair Intelligent Congestion Control  [PDF]
Li Zheng, Doan B. Hoang, Ming Li
Wireless Engineering and Technology (WET) , 2012, DOI: 10.4236/wet.2012.33018
Abstract: More subtle and explicit QoS control mechanisms are required at the radio access level, even though the simple and scalable Differentiated Services (DiffServ) QoS control model is acceptable for the core of the network. At the radio access level, available resources are severely limited and the degree of traffic aggregation is not significant, thus rendering the DiffServ principles less effective. In this paper we present a suitable hybrid QoS architecture framework to address the problem. At the wireless access end, the local QoS mechanism is designed in the context of IEEE 802.11 WLAN with 802.11e QoS extensions; so streams of those session-based applications are admitted, established according to the traffic profile they require, and guaranteed. As the core in the Admission Control of the hybrid QoS architecture, the Fair Intelligent Congestion Control (FICC) algorithm is applied to provide fairness among traffic aggregates and control congestion at the bottleneck interface between the wireless link and the network core via mechanisms of packet scheduling, buffer management, feedback and adjustments. It manages effectively the overloading scenario by preventing traffic violation from uncontrolled traffic, and providing guarantee to the priority traffic in terms of guaranteed bandwidth allocation and specified delay.
Probabilistic Analysis of a Robot System with Redundant Safety Units and Common-Cause Failures  [PDF]
B. S. DHILLON, Zhijian LI
Intelligent Information Management (IIM) , 2009, DOI: 10.4236/iim.2009.13022
Abstract: This paper presents reliability and availability analyses of a model representing a system having one robot and n-redundant safety units with common-cause failures. At least k safety units must function successfully for the robot system success. The robot and other failure rates and the partially failed system repair rates are assumed constant and the failed robot-safety system repair time is assumed arbitrarily distributed. Markov and supplementary variable methods were used to perform mathematical analysis of this model. Generalized expressions for state probabilities, system availabilities, reliability, mean time to failure, and variance of time to failure are developed. Plots of some resulting expressions are shown.
Local Fatigue Evaluation in PZT Thin Films with Nanoparticles by Piezoresponse Force Microscopy
B. S. Li
Smart Materials Research , 2012, DOI: 10.1155/2012/391026
Abstract: Lead zirconate titanate (PZT) thin films with the morphotropic phase boundary composition (Zr/Ti?=?52/48) have been prepared using a modified diol-based sol-gel route by introducing 1–5?mol% barium titanate (BT) nanoseeds into the precursor solution on platinized silicon substrates (Pt/Ti/SiO2/Si). Macroscopic electric properties of PZT film with nanoparticle showed a significant improvement of ferroelectric properties. This work aims at the systematic study of the local switching polarization behavior during fatigue in PZT films with and without nanoparticles by using very recent developed scanning piezoelectric microscopy (SPM). We show that the local fatigue performance, which is characterized by variations of local piezoloop with electric cycles, is significantly improved by adding some nanoseeds. It has been verified by scanning electron microscope (SEM) that the film grain morphology changes from columnar to granular structure with the addition of the nanoseeds. On the other hand, the existence of Pb transition phase, which existed in interface at early crystallization stage of pure PZT thin film, deteriorates the property of the interface. These microstructures and the interfaces of these films significantly affect the electrons injection occurred on the interfaces. The domain wall pinning induced by injected electrons and the succeeding penetration into the films is discussed to explain the fatigue performance. 1. Introduction Lead zirconate titanate (PZT) thin film has been a good candidate for application in ferroelectric materials in nonvolatile ferroelectric random access memory (FERAM) due to its excellent ferroelectric properties [1, 2]. One prerequisite property of PZT thin films for ferroelectric devices is the microscopic perfection of the polarization switching, defined as the symmetric switching between two opposite polarization states. The occurrence of polarization fatigue, which is the decrease of polarization during repeated electrical pulses, has been an obstacle for full commercialization of the PZT thin films, especially for applications of PZT thin films on Pt electrode coated substrates. As such, extensive studies have been carried out to disclose the microscopic fatigue nature in PZT thin films [3–10]. Oxygen vacancies, which are very easy to form during crystallization process and the most mobile point defects in perovskite material like PZT, are deemed to be a major factor in fatigue. Scott et al. argued that the transition of oxygen vacancies into two-dimensional planar arrays is a fatigue mechanism in perovskite
Spatial variability and its scale dependency of observed and modeled soil moisture over different climate regions
B. Li,M. Rodell
Hydrology and Earth System Sciences (HESS) & Discussions (HESSD) , 2013,
Abstract: Past studies on soil moisture spatial variability have been mainly conducted at catchment scales where soil moisture is often sampled over a short time period; as a result, the observed soil moisture often exhibited smaller dynamic ranges, which prevented the complete revelation of soil moisture spatial variability as a function of mean soil moisture. In this study, spatial statistics (mean, spatial variability and skewness) of in situ soil moisture, modeled and satellite-retrieved soil moisture obtained in a warm season (198 days) were examined over three large climate regions in the US. The study found that spatial moments of in situ measurements strongly depend on climates, with distinct mean, spatial variability and skewness observed in each climate zone. In addition, an upward convex shape, which was revealed in several smaller scale studies, was observed for the relationship between spatial variability of in situ soil moisture and its spatial mean when statistics from dry, intermediate, and wet climates were combined. This upward convex shape was vaguely or partially observable in modeled and satellite-retrieved soil moisture estimates due to their smaller dynamic ranges. Despite different environmental controls on large-scale soil moisture spatial variability, the correlation between spatial variability and mean soil moisture remained similar to that observed at small scales, which is attributed to the boundedness of soil moisture. From the smaller support (effective area or volume represented by a measurement or estimate) to larger ones, soil moisture spatial variability decreased in each climate region. The scale dependency of spatial variability all followed the power law, but data with large supports showed stronger scale dependency than those with smaller supports. The scale dependency of soil moisture variability also varied with climates, which may be linked to the scale dependency of precipitation spatial variability. Influences of environmental controls on soil moisture spatial variability at large scales are discussed. The results of this study should be useful for diagnosing large scale soil moisture estimates and for improving the estimation of land surface processes.
Nanomedicine as an emerging approach against intracellular pathogens
Armstead AL, Li B
International Journal of Nanomedicine , 2011, DOI: http://dx.doi.org/10.2147/IJN.S27285
Abstract: nomedicine as an emerging approach against intracellular pathogens Review (5317) Total Article Views Authors: Armstead AL, Li B Published Date December 2011 Volume 2011:6 Pages 3281 - 3293 DOI: http://dx.doi.org/10.2147/IJN.S27285 Andrea L Armstead1–3, Bingyun Li1–3 1Biomaterials, Bioengineering and Nanotechnology Laboratory, Department of Orthopedics, School of Medicine, West Virginia University, Morgantown, WV; 2Pharmaceutical and Pharmacological Sciences, Health Sciences Center, West Virginia University, Morgantown, WV; 3WVNano Initiative, Morgantown, WV, USA Abstract: Diseases such as tuberculosis, hepatitis, and HIV/AIDS are caused by intracellular pathogens and are a major burden to the global medical community. Conventional treatments for these diseases typically consist of long-term therapy with a combination of drugs, which may lead to side effects and contribute to low patient compliance. The pathogens reside within intracellular compartments of the cell, which provide additional barriers to effective treatment. Therefore, there is a need for improved and more effective therapies for such intracellular diseases. This review will summarize, for the first time, the intracellular compartments in which pathogens can reside and discuss how nanomedicine has the potential to improve intracellular disease therapy by offering properties such as targeting, sustained drug release, and drug delivery to the pathogen's intracellular location. The characteristics of nanomedicine may prove advantageous in developing improved or alternative therapies for intracellular diseases.
Spatial variability and its scale dependency of observed and modeled soil moisture under different climate conditions
B. Li,M. Rodell
Hydrology and Earth System Sciences Discussions , 2012, DOI: 10.5194/hessd-9-10245-2012
Abstract: Past studies on soil moisture spatial variability have been mainly conducted in catchment scales where soil moisture is often sampled over a short time period. Because of limited climate and weather conditions, the observed soil moisture often exhibited smaller dynamic ranges which prevented the complete revelation of soil moisture spatial variability as a function of mean soil moisture. In this study, spatial statistics (mean, spatial variability and skewness) of in situ soil moisture measurements (from a continuously monitored network across the US), modeled and satellite retrieved soil moisture obtained in a warm season (198 days) were examined at large extent scales (>100 km) over three different climate regions. The investigation on in situ measurements revealed that their spatial moments strongly depend on climates, with distinct mean, spatial variability and skewness observed in each climate zone. In addition, an upward convex shape, which was revealed in several smaller scale studies, was observed for the relationship between spatial variability of in situ soil moisture and its spatial mean across dry, intermediate, and wet climates. These climate specific features were vaguely or partially observable in modeled and satellite retrieved soil moisture estimates, which is attributed to the fact that these two data sets do not have climate specific and seasonal sensitive mean soil moisture values, in addition to lack of dynamic ranges. From the point measurements to satellite retrievals, soil moisture spatial variability decreased in each climate region. The three data sources all followed the power law in the scale dependency of spatial variability, with coarser resolution data showing stronger scale dependency than finer ones. The main findings from this study are: (1) the statistical distribution of soil moisture depends on spatial mean soil moisture values and thus need to be derived locally within any given area; (2) the boundedness of soil moisture plays a pivoting role in the dependency of soil moisture spatial variability/skewness on its mean (and thus climate conditions); (3) the scale dependency of soil moisture spatial variability changes with climate conditions.
Nanomedicine as an emerging approach against intracellular pathogens
Armstead AL,Li B
International Journal of Nanomedicine , 2011,
Abstract: Andrea L Armstead1–3, Bingyun Li1–31Biomaterials, Bioengineering and Nanotechnology Laboratory, Department of Orthopedics, School of Medicine, West Virginia University, Morgantown, WV; 2Pharmaceutical and Pharmacological Sciences, Health Sciences Center, West Virginia University, Morgantown, WV; 3WVNano Initiative, Morgantown, WV, USAAbstract: Diseases such as tuberculosis, hepatitis, and HIV/AIDS are caused by intracellular pathogens and are a major burden to the global medical community. Conventional treatments for these diseases typically consist of long-term therapy with a combination of drugs, which may lead to side effects and contribute to low patient compliance. The pathogens reside within intracellular compartments of the cell, which provide additional barriers to effective treatment. Therefore, there is a need for improved and more effective therapies for such intracellular diseases. This review will summarize, for the first time, the intracellular compartments in which pathogens can reside and discuss how nanomedicine has the potential to improve intracellular disease therapy by offering properties such as targeting, sustained drug release, and drug delivery to the pathogen's intracellular location. The characteristics of nanomedicine may prove advantageous in developing improved or alternative therapies for intracellular diseases.Keywords: intracellular pathogen, infection, nanomedicine, nanoparticle, drug delivery
Indexing of Motion Capture Data for Efficient and Fast Similarity Search
Chuanjun Li,B. Prabhakaran
Journal of Computers , 2006, DOI: 10.4304/jcp.1.3.35-42
Abstract: As motion capture systems are increasingly used for motion tracking and capture, and more and more surveillance cameras are installed for security protection, more and more motion data, including 3D motion data becomes available, making it important to index motion data for quick retrieval of similar motions. This paper proposes a simple and efficient tree structure for indexing motion data with dozens of attributes. Feature vectors are extracted for indexing by using singular value decomposition (SVD) properties of motion data matrices. By having similar motions with large variations indexed together, searching for similar motions of a query needs only one node traversal at each tree level, and only one feature needs to be considered at one tree level. Experiments with real hand gestures, arm motions and full body motions show that the majority of irrelevant motions can be pruned while retrieving all similar motions, and the traversal of an indexing tree for a querytakes only a few microseconds.
Coefficients of chiral perturbation theory
B. A. Li
Physics , 1997,
Abstract: Based on an effective chiral theory the 10 coefficients of ChPT are predicted. There is no new parameter. The current quark masses, m_{\eta}, f_{K}, and f_{\eta} are determined too.
Beyond the known baryon resonances
B. Saghai,Z. Li
Physics , 2003,
Abstract: eta photoproduction data on the proton up to E=2 GeV are interpreted within a chiral constituent quark formalism, which embodies all known three and four star resonances. This study confirms the need for a new S11 resonance, with M=1.780 GeV and Gamma=280 MeV, already introduced in investigating lower energy data.
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