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Search Results: 1 - 10 of 120136 matches for " Lihui Wang "
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Clusters Merging Method for Short Texts Clustering  [PDF]
Yu Wang, Lihui Wu, Hongyu Shao
Open Journal of Social Sciences (JSS) , 2014, DOI: 10.4236/jss.2014.29032
Abstract:

Under push of Mobile Internet, new social media such as microblog, we chat, question answering systems are constantly emerging. They produce huge amounts of short texts which bring forward new challenges to text clustering. In response to the features of large amount and dynamic growth of short texts, a two-stage clustering method was putted forward. This method adopted a sliding window sliding on the flow of short texts. Inside the slide window, hierarchical clustering method was used, and between the slide windows, clusters merging method based on information gain was adopted. Experiment indicated that this method is fast and has a higher accuracy.

Stability of BTZ black strings
Lihui Liu,Bin Wang
Physics , 2008, DOI: 10.1103/PhysRevD.78.064001
Abstract: We study the dynamical stability of the BTZ black string against fermonic and gravitational perturbations. The BTZ black string is not always stable against these perturbations. There exist threshold values for $m^2$ related to the compactification of the extra dimension for fermonic perturbation, scalar part of the gravitational perturbation and the tensor perturbation, respectively. Above the threshold values, perturbations are stable; while below these thresholds, perturbations can be unstable. We find that this non-trivial stability behavior qualitatively agrees with that predicted by a thermodynamical argument, showing that the BTZ black string phase is not the privileged stable phase.
Numerical Calculation of Viscous-Elastic Fluid Flooding Residual Oil Film in the Complex Pore  [PDF]
Lili Liu, Chao Yu, Lihui Wang, Lu Liu
Open Journal of Fluid Dynamics (OJFD) , 2013, DOI: 10.4236/ojfd.2013.33019
Abstract:

In order to analyze the stress and deformation of different permeability of residual oil film in the complex pore, which are affected by the viscous-elasticity of the fluid, the hydrodynamic displacement mechanism is explored from the stand-point of hydrodynamics, that is, the residual oil film displaced by alternating injection of different concentrations of the polymer solution, viscous-elastic fluid flow equation is established in the complex pore by choosing continuity equation, motion equation and the upper convected Maxwell constitutive equation. The flow field is computed by using the method of numerical analysis. Not only the stress and deformation of residual oil film on the different permeability of micro pores, but also the analysis of the flooding mechanism of alternating injection of different concentrations of the polymer solution is got. The results show that the larger the viscous-elasticity of polymer solution is, the bigger the normal deviatoric stress acting on the residual oil film is; the distribution of normal deviatoric stress has the abrupt change. The stronger the viscous-elasticity of the polymer solution is, the bigger the horizontal stress difference acting on the residual oil film is and the more obvious the deformation is; the high-concentration polymer solution is suitable for high-permeability micro pores. Low-concentration polymer solution is suitable for medium and low-permeability micro pores. Alternating injection of polymer solution can improve

Mechanical Analysis of Viscous-Elastic Fluid Acting on Residual Oil in the Micro Pore  [PDF]
Lili Liu, Chao Yu, Lihui Wang, Chengchuyue Fu, Peixiang Li
Open Journal of Fluid Dynamics (OJFD) , 2013, DOI: 10.4236/ojfd.2013.34030
Abstract: In order to analyze the normal deviatoric stress that viscous-elastic fluid acting on the residual oil under the situation of different flooding conditions and different permeabilities, Viscous-elastic fluid flow equation is established in the micro pore by choosing the continuity equation, motion equation and the upper-convected Maxwell constitutive equation, the flow field is computed by using numerical analysis, the forces that driving fluid acting on the residual oil in micro pore are got, and the influence of flooding conditions, pore width and viscous-elasticity of driving fluid on force is compared and analyzed. The results show that: the more viscous-elasticity of driving fluid increases, the greater the normal deviatoric stress acting on the residual oil increases; using constant pressure gradient flooding, the lager the pore width is, the greater normal deviatoric stress acting on the residual oil will be.
Analysis of the Force Acting on the Sucker Rod by Polymer Solution  [PDF]
Lili Liu, Shuren Yang, Lihui Wang, Di Xu, Liang Zhao, Yue Cui
Open Journal of Fluid Dynamics (OJFD) , 2014, DOI: 10.4236/ojfd.2014.42009
Abstract:

With selecting lower-convected Maxwell constitutive equation, polymer solution flow equation in eccentric annulus is established. And the distribution rule of the force acting on the sucker rod by polymer solution has been gained. The result shows the eccentric ratio and the movement velocity of the sucker rod are major influence factors on the radial force. The greater the ratio is, the greater the force of sucker rod is. Then the eccentric wear is easier to appear.

Numerical Calculation of the Horizontal Stress Difference of Viscous-Elastic Fluid Acting on the Residual Oil in Micro Pore  [PDF]
Lili Liu, Shuren Yang, Lihui Wang, Di Xu, Liang Zhao, Yue Cui
Open Journal of Fluid Dynamics (OJFD) , 2014, DOI: 10.4236/ojfd.2014.42010
Abstract: In order to analyze the microscopic theory of viscous-elastic fluid flooding residual oil, the flow equation of polymer solution in the micro pore can be derived by selecting upper-convected Maxwell constitutive equation, continuity equation and motion equation. Then, the flow velocity field and stress field can be calculated under the boundary condition, and with the theory of stress tensor, the horizontal stress difference of polymer solution acting on the residual oil can be calculated. The results show that the greater the elasticity of viscous-elastic fluid is, the wider the flow channel is, the greater the horizontal stress difference is. The force acting on residual oil by viscous-elastic fluid can be increased by increasing the concentration of the polymer solution.
Design Navigation Computer System Based on Double Digital Signal Process and FPGA
Jie Yan,Xiaosu Xu,Lihui Wang
International Journal of Online Engineering (iJOE) , 2013, DOI: 10.3991/ijoe.v9is2.2579
Abstract: The article describes the design and implementation of integrated navigation embedded computer system based on double DSP and FPGA. In the system, TMS320C6727 (C6727) and TMS320C6713 (C6713) digital signal processor (DSP), which produced by TI are used as the core processing chip. C6727 is responsibility to de-noising the inertial measurement unit (IMU) original signal, and send the IMU data to C6713. C6713 is responsibility to collect the IMU and GNSS data, run navigation algorithm and send the navigation information to other implements. The I/0 interface, timing control, data buffering and address bus decoding modes are implemented in FPGA. This design can improve the system real-time performance and reliability.
Drosophila as a model to study the role of blood cells in inflammation, innate immunity and cancer
Lihui Wang,Ilias Kounatidis,Petros Ligoxygakis
Frontiers in Cellular and Infection Microbiology , 2014, DOI: 10.3389/fcimb.2013.00113
Abstract: Drosophila has a primitive yet effective blood system with three types of haemocytes which function throughout different developmental stages and environmental stimuli. Haemocytes play essential roles in tissue modeling during embryogenesis and morphogenesis, and also in innate immunity. The open circulatory system of Drosophila makes haemocytes ideal signal mediators to cells and tissues in response to events such as infection and wounding. The application of recently developed and sophisticated genetic tools to the relatively simple genome of Drosophila has made the fly a popular system for modeling human tumorigensis and metastasis. Drosophila is now used for screening and investigation of genes implicated in human leukemia and also in modeling development of solid tumors. This second line of research offers promising opportunities to determine the seemingly conflicting roles of blood cells in tumor progression and invasion. This review provides an overview of the signaling pathways conserved in Drosophila during haematopoiesis, haemostasis, innate immunity, wound healing and inflammation. We also review the most recent progress in the use of Drosophila as a cancer research model with an emphasis on the roles haemocytes can play in various cancer models and in the links between inflammation and cancer.
Study on the Drift of Modulated Phase in Interference Fiber Optic Gyroscope
Feng Sun,Lihui Wang,Gang Wang,Gang Liu
Journal of Computers , 2010, DOI: 10.4304/jcp.5.3.394-400
Abstract: Integrated optical chip (IOC) is an essential component in the closed-loop interference fiber optic gyroscope(IFOG) system. One of the main functions of IOC in IFOG is to modulate the phase, which includes the π/2 phase biased by square waves and Sagnac phase biased by ladder waves. In fact, both square waves and ladder waves have high frequency, including multiple harmonic waves and being disturbed easily, which induce the drift of modulated phase in IOC, and has great effect on IFOG performance, such as zero bias and drift. This paper analyzes theoretically the relationship between two kinds of modulated phases and the performance of IFOG drift, and searches for the error information in two kinds of modulated phases. Focusing on different error factors in IOC, the system is optimized in aspects of power source, clock, electromagnetic compatibility (EMC), signal processing and so on, to restrain phase drift error of 2π, then to improve the bias stability of IFOG. Signals of the power source, clock, EMC, and signal processing and so on are tested, the test results show that all these methods are effective to restrain the drift of modulated phase in IOC, the system is stable and reliable. The static testing data of FOG is obtained in Three-axis Turntable, and the static testing data is analyzed quantitatively by using the method of Allan variance to identify random errors related to the drift of modulated phase from all kinds of error sources in the FOG system. The result is shown that the bias stability of the FOG system is better than 0.03°/hr. We also obtained the dynamic testing data of FOG in Three-axis Turntable, the result is shown that scale factor stability of the FOG system is better than 25ppm. To sum up, the whole performance of the IFOG system can meet the requirements of inertial navigation system (INS) with high precision.
Aurora-A Interacts with AP-2α and Down Regulates Its Transcription Activity
Lihui Zou, Yimin Sun, Mingrong Wang, Qimin Zhan
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0023110
Abstract: Aurora-A is a serine/threonine protein kinase and plays an important role in the control of mitotic progression. Dysregulated expression of Aurora-A impairs centrosome separation and maturation, which lead to disrupted cell cycle progression and tumorigenesis. However, the molecular mechanism by which Aurora-A causes cell malignant transformation remains to be further defined. In this report, using transcription factors array and mRNA expression profiling array, we found that overexpression of Aurora-A suppressed transcription activity of AP-2α, a tumor suppressor that is often downregulated in variety of tumors, and inhibited expression of AP-2α-regulated downstream genes. These array-based observations were further confirmed by microwell colorimetric TF assay and luciferase reporter assay. Downregulated transcription activity of AP-2α by Aurora-A was found to be associated with reduced AP-2α protein stability, which appeared to be mediated by Aurora-A enhanced ubiquitin-dependent proteasomal degradation of AP-2α protein. Interestingly, Aurora-A-mediated AP-2α degradation was likely dependent Aurora-A kinase activity since inhibition of Aurora-A kinase activity was able to rescue Aurora-A-induced degradation of AP-2α. Moreover, we defined a physical interaction between Aurora-A and AP-2α, and such interaction might bridge the suppressive effect of Aurora-A on AP-2α protein stability. These findings provide new insights into molecular mechanism by which Aurora-A acts as an oncogenic molecule in tumor occurrence and malignant development.
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