35,632 research outputs found
Deprojection technique for galaxy cluster considering point spread function
We present a new method for the analysis of Abell 1835 observed by
XMM-Newton. The method is a combination of the Direct Demodulation technique
and deprojection. We eliminate the effects of the point spread function (PSF)
with the Direct Demodulation technique. We then use a traditional depro-jection
technique to study the properties of Abell 1835. Compared to that of
deprojection method only, the central electron density derived from this method
increases by 30%, while the temperature profile is similar.Comment: accepted for publication in Sciences in China -- G, the Black Hole
special issu
Transport through the intertube link between two parallel carbon nanotubes
Quantum transport through the junction between two metallic carbon nanotubes
connected by intertube links has been studied within the TB method and Landauer
formula. It is found that the conductance oscillates with both of the coupling
strength and length. The corresponding local density of states (LDOS) is
clearly shown and can be used to explain the reason why there are such kinds of
oscillations of the conductances, which should be noted in the design of
nanotube-based devices.Comment: 6 pages, 4 figure
A general software defect-proneness prediction framework
This is the author's accepted manuscript. The final published article is available from the link below. Copyright @ 2011 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works.BACKGROUND - Predicting defect-prone software components is an economically important activity and so has received a good deal of attention. However, making sense of the many, and sometimes seemingly inconsistent, results is difficult. OBJECTIVE - We propose and evaluate a general framework for software defect prediction that supports 1) unbiased and 2) comprehensive comparison between competing prediction systems. METHOD - The framework is comprised of 1) scheme evaluation and 2) defect prediction components. The scheme evaluation analyzes the prediction performance of competing learning schemes for given historical data sets. The defect predictor builds models according to the evaluated learning scheme and predicts software defects with new data according to the constructed model. In order to demonstrate the performance of the proposed framework, we use both simulation and publicly available software defect data sets. RESULTS - The results show that we should choose different learning schemes for different data sets (i.e., no scheme dominates), that small details in conducting how evaluations are conducted can completely reverse findings, and last, that our proposed framework is more effective and less prone to bias than previous approaches. CONCLUSIONS - Failure to properly or fully evaluate a learning scheme can be misleading; however, these problems may be overcome by our proposed framework.National Natural Science Foundation of
Chin
SPSA-Based Tracking Method for Single-Channel-Receiver Array
A novel tracking method in the phased antenna array with a single-channel receiver for the moving signal source is presented in this paper. And the problems of the direction-of-arrival track and beamforming in the array system are converted to the power maximization of received signal in the free-interference conditions, which is different from the existing algorithms that maximize the signal to interference and noise ratio. The proposed tracking method reaches the global optimum rather than local by injecting the extra noise terms into the gradient estimation. The antenna beam can be steered to coincide with the direction of the moving source fast and accurately by perturbing the output of the phase shifters during motion, due to the high efficiency and easy implementation of the proposed beamforming algorithm based on the simultaneous perturbation stochastic approximation (SPSA). Computer simulations verify that the proposed tracking scheme is robust and effective
Quantum dynamics of an Ising spin-chain in a random transverse field
We consider an Ising spin-chain in a random transverse magnetic field and
compute the zero temperature wave vector and frequency dependent dynamic
structure factor numerically by using Jordan-Wigner transformation. Two types
of distributions of magnetic fields are introduced. For a rectangular
distribution, a dispersing branch is observed, and disorder tends to broaden
the dispersion peak and close the excitation gap. For a binary distribution, a
non-dispersing branch at almost zero energy is recovered. We discuss the
relationship of our work to the neutron scattering measurement in
.Comment: 4 pages and 6 eps figures; minor clarifications were made; the text
was shortened to add an additional figur
Kinase suppressor of Ras 2 is involved in regulation of cell proliferation and is up-regulated in human invasive ductal carcinomas of breast
Aim: To study the expression of Kinase Suppressor of Ras 2 (KSR2) in human breast tumors and its effect on proliferation of breast epithelial cells. We reported previously that KSR2 was up-regulated in immortalized human breast epithelial cells. Methods: Proteomics technologies, systems biology tool for a KSR2 network analysis, immunoblotting, siRNA technology, overexpression of KSR2, cell proliferation assays and immunohistochemistry of tissue microarray of human breast tumors and normal breast tissue were used. Results: In conditionally immortalized primary epithelial cells KSR2 expression was shown to be up-regulated. The involvement of KSR2 in regulation of cell proliferation was predicted by a KSR2-centered network analysis. We observed that KSR2 down-regulation with specific siRNA inhibited cell proliferation. By immunohistochemistry of tissue microarray it was demon strated that KSR2 expression was enhanced in human invasive breast carcinomas. Conclusion: Our findings propose KSR2 as a new marker of immortalization, which has an impact on cell proliferation
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