oalib

Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99

Submit

Any time

2019 ( 53 )

2018 ( 1474 )

2017 ( 1305 )

2016 ( 1354 )

Custom range...

Search Results: 1 - 10 of 92168 matches for " X. Liu "
All listed articles are free for downloading (OA Articles)
Page 1 /92168
Display every page Item
ACTA MATHEMATICA UNIVERSITATIS COMENIANAE
X. Liu
ACTA MATHEMATICA UNIVERSITATIS COMENIANAE , 2001,
Abstract: . In this paper, we characterize the complete space-like submanifolds with parallel mean curvature vector satisfying $H^2=\frac{4(n-1)c}{n^2}$ in the de Sitter space completely.
VLBI observation of giant radio galaxy J1313+696 at 2.3/8.4 GHz
X. Liu,J. Liu
Physics , 2010, DOI: 10.1007/s10509-008-9964-7
Abstract: We report the result of VLBI observation of the giant radio galaxy J1313+696 (4C +69.15) at 2.3/8.4 GHz, only the core component of the giant radio galaxy was detected in the VLBI observation at the dual frequencies. The result shows a steep spectrum core with $\alpha=-0.82$ ($S \propto \nu^{\alpha}$) between 2.3 GHz and 8.4 GHz. The steep spectrum core may be a sign of renewed activity. Considering also the upper limit flux density of 2.0 mJy at 0.6 GHz from Konar et al. 2004 the core has a GHz-peaked spectrum, implying that the core is compact and absorbed. Further high resolution VLBI observations are needed to identify if the steep spectrum core is consisting of a core and steep spectrum jet.
Real-Time Timing Channel Detection in a Software-Defined Networking Virtual Environment  [PDF]
Anyi Liu, Jim X. Chen, Harry Wechsler
Intelligent Information Management (IIM) , 2015, DOI: 10.4236/iim.2015.76023
Abstract: Despite extensive research, timing channels (TCs) are still known as a principal category of threats that aim to leak and transmit information by perturbing the timing or ordering of events. Existing TC detection approaches use either signature-based approaches to detect known TCs or anomaly-based approach by modeling the legitimate network traffic in order to detect unknown TCs. Un-fortunately, in a software-defined networking (SDN) environment, most existing TC detection approaches would fail due to factors such as volatile network traffic, imprecise timekeeping mechanisms, and dynamic network topology. Furthermore, stealthy TCs can be designed to mimic the legitimate traffic pattern and thus evade anomalous TC detection. In this paper, we overcome the above challenges by presenting a novel framework that harnesses the advantages of elastic re-sources in the cloud. In particular, our framework dynamically configures SDN to enable/disable differential analysis against outbound network flows of different virtual machines (VMs). Our framework is tightly coupled with a new metric that first decomposes the timing data of network flows into a number of using the discrete wavelet-based multi-resolution transform (DWMT). It then applies the Kullback-Leibler divergence (KLD) to measure the variance among flow pairs. The appealing feature of our approach is that, compared with the existing anomaly detection approaches, it can detect most existing and some new stealthy TCs without legitimate traffic for modeling, even with the presence of noise and imprecise timekeeping mechanism in an SDN virtual environment. We implement our framework as a prototype system, OBSERVER, which can be dynamically deployed in an SDN environment. Empirical evaluation shows that our approach can efficiently detect TCs with a higher detection rate, lower latency, and negligible performance overhead compared to existing approaches.
N* Masses from QCD Sum Rules
X. Liu,F. X. Lee
Physics , 2001,
Abstract: We report N* masses in the spin-1/2 and spin-3/2 sectors using the method of QCD Sum Rules. They are based on three independent sets derived from generalized interpolating fields. The predictive ability of each sum rule is examined by a Monte-Carlo based analysis procedure in which all three phenomenological parameters (mass, coupling, threshold) are extracted simultaneously. A parity projection technique is also studied.
Very deep spectroscopy of the bright Saturn Nebula NGC 7009 -- I. Observations and plasma diagnostics
X. Fang,X. -W. Liu
Physics , 2011, DOI: 10.1111/j.1365-2966.2011.18681.x
Abstract: We present very deep CCD spectrum of the bright, medium-excitation planetary nebula NGC 7009, with a wavelength coverage from 3040 to 11000 A. Traditional emission line identification is carried out to identify all the emission features in the spectra, based on the available laboratory atomic transition data. Since the spectra are of medium resolution, we use multi-Gaussian line profile fitting to deblend faint blended lines, most of which are optical recombination lines (ORLs) emitted by singly ionized ions of abundant second-row elements such as C, N, O and Ne. Computer-aided emission-line identification, using the code EMILI developed by Sharpee et al., is then employed to further identify all the emission lines thus obtained. In total about 1200 emission features are identified, with the faintest ones down to fluxes 10^{-4} of H_beta. The flux errors for all emission lines, estimated from multi-Gaussian fitting, are presented. Plots of the whole optical spectrum, identified emission lines labeled, are presented along with the results of multi-Gaussian fits. Plasma diagnostics using optical forbidden line ratios are carried out. Also derived are electron temperatures and densities from the H I, He I and He II recombination spectrum.
Internal Josephson-Like Tunneling in Two-Component Bose-Einstein Condensates Affected by Sign of the Atomic Interaction and External Trapping Potential
Bo Xiong,X. X. Liu
Physics , 2007, DOI: 10.1088/1009-1963/16/9/013
Abstract: We study the Josephson-like tunneling in two-component Bose-Einstein condensates coupled with microwave field in respond to various attractive and repulsive atomic interaction under the various aspect ratio of trapping potential and the gravitational field. It is very interesting to find that the dynamic of Josephson-like tunneling can be controlled from fast damped oscillations and asymmetric occupation to nondamped oscillation and symmetric occupation.
Getting Started in Tiling Microarray Analysis
X. Shirley Liu
PLOS Computational Biology , 2007, DOI: 10.1371/journal.pcbi.0030183
Abstract:
The Two-layer Surface Energy Balance Parameterization Scheme (TSEBPS) for estimation of land surface heat fluxes
X. Xin ,Q. Liu
Hydrology and Earth System Sciences (HESS) & Discussions (HESSD) , 2010,
Abstract: A Two-layer Surface Energy Balance Parameterization Scheme (TSEBPS) is proposed for the estimation of surface heat fluxes using Thermal Infrared (TIR) data over sparsely vegetated surfaces. TSEBPS is based on the theory of the classical two-layer energy balance model, as well as a set of new formulations derived from assumption of the energy balance at limiting cases. Two experimental data sets are used to assess the reliabilities of TSEBPS. Based on these case studies, TSEBPS has proven to be capable of estimating heat fluxes at vegetation surfaces with acceptable accuracy. The uncertainties in the estimated heat fluxes are comparable to in-situ measurement uncertainties.
The two-layer surface energy balance parameterization scheme (TSEBPS) for estimation of land surface heat fluxes
X. Xin,Q. Liu
Hydrology and Earth System Sciences Discussions , 2009,
Abstract: A Two-layer Surface Energy Balance Parameterization Scheme (TSEBPS) is proposed for the estimation of surface heat fluxes using thermal infrared (TIR) data over sparsely vegetated surfaces. TSEBPS is based on the theory of the classical two-layer energy balance model, as well as a set of new formulations derived from assumption of the energy balance at limiting cases. Two experimental data sets are used to assess the reliabilities of TSEBPS. Based on these case studies, TSEBPS has proven to be capable of estimating heat fluxes at vegetation surfaces with acceptable accuracy. The uncertainties in the estimated heat fluxes are comparable to in-situ measurement uncertainties.
Optical recombination lines and temperature fluctuations
X. W. Liu
Revista mexicana de astronomía y astrofísica , 2002,
Abstract: Hace tres d ecadas que Peimbert encontr o que las temperaturas del salto de Balmer en regiones H II y planetarias (PNe) son sistem aticamente menores a las obtenidas con las l neas del [O III]. Sugiri o que debido a la existencia de uctuaciones de la temperatura, las abundancias de elementos pesados derivadas de l neas de excitaci on colisional (CELs) eran sistem aticamente subestimadas. En este trabajo hago una revisi on de las determinaciones recientes de elementos pesados en PNe con l neas d ebiles de elementos pesados (ORLs). En todas las especies i onicas estudiadas, las ORLs dan abundancias mayores que las CELs. El cociente de abundancias ORL a CEL var a de objeto a objeto y est a correlacionado con la diferencia de temperaturas del [O III] y del salto de Balmer. Las uctuaciones de temperatura y densidad solas no pueden explicar las grandes discrepancias en abundancias obtenidas con ORL y CEL en un n umero peque~no de nebulosas. Se sugiere que estos casos extremos pueden contener regiones ricas en metales similares a las observadas en PN rejuvenecidas, como Abell 30.
Page 1 /92168
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.