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Search Results: 1 - 10 of 120753 matches for " Xiaofeng Wang "
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Exotic Collective Excitations at High Spin: Triaxial Rotation and Octupole Condensation
Xiaofeng Wang
Physics , 2008,
Abstract: In this thesis work, two topics, triaxiality and reflection asymmetry, have been discussed. Band structures in $^{163}$Tm were studied in a "thin" target experiment as well as in a DSAM lifetime measurement. Two new excited bands were shown to be characterized by a deformation larger than that of the yrast sequence. These structures have been interpreted as Triaxial Strongly Deformed bands associated with particle-hole excitations, rather than with wobbling. Moreover, the Tilted-Axis Cranking calculations provide a natural explanation for the presence of wobbling bands in the Lu isotopes and their absence in the neighboring Tm, Hf and Ta nuclei. A series of so-called "unsafe" Coulomb excitation experiments as well as one-neutron transfer measurements was carried out to investigate the role of octupole correlations in the $^{238,240,242}$Pu isotopes. Some striking differences exist between the level scheme and deexcitation patterns seen in $^{240}$Pu, and to a lesser extent in $^{238}$Pu, and those observed in $^{242}$Pu and in many other actinide nuclei such as $^{232}$Th and $^{238}$U, for example. The differences can be linked to the strength of octupole correlations, which are strongest in $^{240}$Pu. Further, all the data find a natural explanation within the recently proposed theoretical framework of octupole condensation.
Cognitive Cycle in Mind Model CAM  [PDF]
Zhongzhi Shi, Xiaofeng Wang, Jinpeng Yue
International Journal of Intelligence Science (IJIS) , 2011, DOI: 10.4236/ijis.2011.12004
Abstract: Cognitive cycle is a basic procedure of mental activities in cognitive level. Human cognition consists of cascading cycles of recurring brain events. This paper presents a cognitive cycle for the mind model CAM (Consciousness And Memory). Each cognitive cycle perceives the current situation, through motivation phase with reference to ongoing goals, and then composes internal or external action streams to reach the goals in response. We use dynamic description logic which is an extended description logic with action to formalize descriptions and algorithms of cognitive cycle. Two important algorithms, including hierarchical goal and action composition, is proposed in the paper.
Bandwidth Selection for Weighted Kernel Density Estimation
Bin Wang,Xiaofeng Wang
Statistics , 2007,
Abstract: In the this paper, the authors propose to estimate the density of a targeted population with a weighted kernel density estimator (wKDE) based on a weighted sample. Bandwidth selection for wKDE is discussed. Three mean integrated squared error based bandwidth estimators are introduced and their performance is illustrated via Monte Carlo simulation. The least-squares cross-validation method and the adaptive weight kernel density estimator are also studied. The authors also consider the boundary problem for interval bounded data and apply the new method to a real data set subject to informative censoring.
Experimental Research of Dual-Polarization Passive Radar Based on DTTB Signal  [PDF]
Yonghu Zeng, Xiaofeng Ai, Liandong Wang, Xiaoyang Wang, Guangyong Zheng
Journal of Computer and Communications (JCC) , 2016, DOI: 10.4236/jcc.2016.43016
Abstract:

The passive radar is a hot research topic. A multi-channel wideband passive radar experimental system is designed and the digital television terrestrial broadcasting (DTTB) signal is chosen to carry out the target detection experiment of civil aviation aircraft. The polarization and spatial filtering methods are used to solve the strong direct path interference suppression problems brought by the receiving system location; combined with the characteristics of DTTB signal, the block length selection interval in the block batch processing method for range-Doppler images calculation is given; the clutter suppression performance is compared through the experimental data receiving from different bistatic polarization channels, the conclusion is different from the monostatic radar and it can guide the passive radar experiment.

Advances of DNA Methylation in Lung Cancer
Haibing WANG,Xiaofeng CHEN
Chinese Journal of Lung Cancer , 2010,
Abstract:
What is User Experience Really: towards a UX Conceptual Framework
Stefan Hellweger,Xiaofeng Wang
Computer Science , 2015,
Abstract: For more then a decade the term User Experience (UX) has been highly debated and defined in many ways. However, often UX remains as a vague concept and it may be hard to understand the very nature of it. In this paper we aimed at providing a better understanding of this concept. We explored the multi-faceted UX literature, reviewing the current state-of- the-art knowledge and emphasizing the multi-dimensional nature of the concept. Based on the literature review we built a conceptual framework of UX using the elements that are linked to it and reported in different studies. To show the potential use of the framework, we examined the UX delivered by different phone applications on different mobile devices using the elements in the framework. Several interesting insights have been obtained in terms of how the phone applications deliver different UX. Our study opens up a promising line of investigating the contemporary meaning of UX.
Hidden Sequence Repeats: Additional Evidence for the Origin of TIM-Barrel Family  [PDF]
Xiaofeng Ji, Yuan Zheng, Zhipeng Wang, Jun Sheng
Journal of Biomedical Science and Engineering (JBiSE) , 2016, DOI: 10.4236/jbise.2016.96025
Abstract: Most proteins adopt an approximate structural symmetry. However, they have no symmetry detectable in their sequences and it is unclear for most of these proteins whether their structural symmetry originates from duplication. As one of the six popular folds (super-folds) possessing an approximate structural symmetry, the triosephosphate isomerase barrel (TIM-barrel) domain has been widely studied. Using modified recurrent quantification analysis of primary sequences, we identified the same 2-, 3-, and 4-fold symmetry pattern as their tertiary structures. This result indicates that the symmetry in tertiary structure is coded by symmetry in the primary sequence and that the TIM-barrel adopts a 2-, 3-, or 4-fold repeat pattern during evolution. This discovery will be useful for understanding the evolutionary mechanisms of this protein family and the symmetry pattern that may be a clue into the ancient origin of duplication of half-barrels or the β a unit.
Addition of External Organic Carbon and Native Soil Organic Carbon Decomposition: A Meta-Analysis
Weidong Zhang, Xiaofeng Wang, Silong Wang
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0054779
Abstract: Background Extensive studies have been conducted to evaluate the effect of external organic Carbon on native soil organic carbon (SOC) decomposition. However, the direction and extent of this effect reported by different authors is inconsistent. Objective The objective was to provide a synthesis of existing data that comprehensively and quantitatively evaluates how the soil chemical properties and incubation conditions interact with additional external organic C to affect the native SOC decomposition. Data Source A meta-analysis was conducted on previously published empirical studies that examined the effect of the addition of external organic carbon on the native SOC decomposition through isotopic techniques. Results and Conclusions The addition of external organic C, when averaged across all studies, enhanced the native SOC decomposition by 26.5%. The soil with higher SOC content and fine texture showed significantly higher priming effects, whereas the soil with higher total nitrogen content showed an opposite trend. The soils with higher C:N ratios had significantly stronger priming effects than those with low C:N ratios. The decomposition of native SOC was significantly enhanced more at early stage of incubation (<15d) than at the later stages (>15d). In addition, the incubation temperature and the addition rate of organic matter significantly influenced the native SOC decomposition in response to the addition of external organic C.
Cluster Consensus on Discrete-Time Multi-Agent Networks
Li Xiao,Xiaofeng Liao,Huiwei Wang
Abstract and Applied Analysis , 2012, DOI: 10.1155/2012/274735
Abstract: Nowadays, multi-agent networks are ubiquitous in the real world. Over the last decade, consensus has received an increasing attention from various disciplines. This paper investigates cluster consensus for discrete-time multi-agent networks. By utilizing a special coupling matrix and the Kronecker product, a criterion based on linear matrix inequality (LMI) is obtained. It is shown that the addressed discrete-time multi-agent networks achieve cluster consensus if a certain LMI is feasible. Finally, an example is given to demonstrate the effectiveness of the proposed criterion.
Ship Detection in SAR Image Based on the Alpha-stable Distribution
Changcheng Wang,Mingsheng Liao,Xiaofeng Li
Sensors , 2008, DOI: 10.3390/s8084948
Abstract: This paper describes an improved Constant False Alarm Rate (CFAR) ship detection algorithm in spaceborne synthetic aperture radar (SAR) image based on Alphastable distribution model. Typically, the CFAR algorithm uses the Gaussian distribution model to describe statistical characteristics of a SAR image background clutter. However, the Gaussian distribution is only valid for multilook SAR images when several radar looks are averaged. As sea clutter in SAR images shows spiky or heavy-tailed characteristics, the Gaussian distribution often fails to describe background sea clutter. In this study, we replace the Gaussian distribution with the Alpha-stable distribution, which is widely used in impulsive or spiky signal processing, to describe the background sea clutter in SAR images. In our proposed algorithm, an initial step for detecting possible ship targets is employed. Then, similar to the typical two-parameter CFAR algorithm, a local process is applied to the pixel identified as possible target. A RADARSAT-1 image is used to validate this Alpha-stable distribution based algorithm. Meanwhile, known ship location data during the time of RADARSAT-1 SAR image acquisition is used to validate ship detection results. Validation results show improvements of the new CFAR algorithm based on the Alpha-stable distribution over the CFAR algorithm based on the Gaussian distribution.
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