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Search Results: 1 - 10 of 91365 matches for " Luo LIU "
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QoS in Node-Disjoint Routing for Ad Hoc Networks  [PDF]
Luo LIU, Laurie CUTHBERT
Int'l J. of Communications, Network and System Sciences (IJCNS) , 2008, DOI: 10.4236/ijcns.2008.11011
Abstract: Ad hoc network (MANET) is a collection of mobile nodes that can communicate with each other without using any fixed infrastructure. To support multimedia applications such as video and voice MANETs require an efficient routing protocol and quality of service (QoS) mechanism. Node-Disjoint Multipath Routing Protocol (NDMR) is a practical protocol in MANETs: it reduces routing overhead dramatically and achieves multiple node-disjoint routing paths. QoS support in MANETs is an important issue as best-effort routing is not efficient for supporting multimedia applications. This paper presents a novel adaptation of NDMR, QoS enabled NDMR, which introduces agent-based SLA management. This enhancement allows for the intelligent selection of node-disjoint routes based on network conditions, thus fulfilling the QoS requirements of Service Level Agreements (SLAs).
Comparison between Peer Feedback and Automated Feedback in College English Writing: A Case Study  [PDF]
Yang Luo, Yan Liu
Open Journal of Modern Linguistics (OJML) , 2017, DOI: 10.4236/ojml.2017.74015
Abstract: As written feedback is an indispensable component of instructing and learning process, the implementation of effective feedback plays a key role in improving non-English majors’ writing skill. Peers and automated writing evaluation systems are new, main sources of feedback providers in college English writing. This paper compares three feedback conditions: individual and group modes in peer feedback and automated feedback. Analysis is made on distribution features from feedback types, dimensions of assessment rubric, aspects of organization and linguistic performance, and reflected attitudes. The findings indicate automated mode and group mode take turns dominating in non-corrective feedback and corrective feedback; group mode takes the lead in both direct and indirect feedback; individual, group and automated modes underemphasize global feedback. Dimensions are found to centre on linguistic performance, followed by organization, content and format, differences and similarities of specific aspects and attitudes are also found in all three modes. Further investigations are undertaken into students’ perceptions towards peer feedback and automated feedback, with their respective merits and demerits summed up. On the basis of all the findings, key elements of sociocultural theory are explored to provide multi-dimensional feedback scaffolding for students of lower-intermediate level in facilitating college English writing.
Uncertain IMM Estimator for Multi-Sensor Target Tracking  [PDF]
Ming CEN, Xingfa LIU, Daisheng LUO
Communications and Network (CN) , 2009, DOI: 10.4236/cn.2009.12011
Abstract: Interacting Multiple Model (IMM) estimator can provide better performance of target tracking than mono model Kalman filter. In multi-sensor system ordinarily, availability of measurement from different sensors is stochastic, and it is difficult to construct uniform global observation vector and observation matrix appropri-ately in existing method. An IMM estimator for uncertain measurement is presented. By the method invalid measurement is regarded as outlier, and approximation is reconstructed by feedback of system state estima-tion of fusion center. Then nominally generalized certain measurement can be obtained by substituting re-constructed one for invalid one. The generalized certain measurement can be centralized to construct global measurement and provided to IMM estimator, and existing multi-sensor IMM estimation method is general-ized to uncertain environment. Theoretical analysis and simulation results show the effectiveness of the method.
Clustering Analysis of Stocks of CSI 300 Index Based on Manifold Learning  [PDF]
Ruiling Liu, Hengjin Cai, Cheng Luo
Journal of Intelligent Learning Systems and Applications (JILSA) , 2012, DOI: 10.4236/jilsa.2012.42011
Abstract: As an effective way in finding the underlying parameters of a high-dimension space, manifold learning is popular in nonlinear dimensionality reduction which makes high-dimensional data easily to be observed and analyzed. In this paper, Isomap, one of the most famous manifold learning algorithms, is applied to process closing prices of stocks of CSI 300 index from September 2009 to October 2011. Results indicate that Isomap algorithm not only reduces dimensionality of stock data successfully, but also classifies most stocks according to their trends efficiently.
General Concave Integral Control  [PDF]
Baishun Liu, Xiangqian Luo, Jianhui Li
Intelligent Control and Automation (ICA) , 2013, DOI: 10.4236/ica.2013.44042
Abstract:

In this paper, a class of fire-new general integral control, named general concave integral control, is proposed. It is derived by normalizing the bounded integral control action and concave function gain integrator, introducing the partial derivative of Lyapunov function into the integrator and originating a class of new strategy to transform ordinary control into general integral control. By using Lyapunov method along with LaSalle’s invariance principle, the theorem to ensure regionally as well as semi-globally asymptotic stability is established only by some bounded information. Moreover, the highlight point of this integral control strategy is that the integrator output could tend to infinity but the integral control action is finite. Therefore, a simple and ingenious method to design general integral control is founded. Simulation results showed that under the normal and perturbed cases, the optimum response in the whole domain of interest can all be achieved by a set of the same control gains, even under the case that the payload is changed abruptly.

General Integral Control Design via Feedback Linearization  [PDF]
Baishun Liu, Jianhui Li, Xiangqian Luo
Intelligent Control and Automation (ICA) , 2014, DOI: 10.4236/ica.2014.51003
Abstract:

Based on the feedback linearization technique, we present a systematic design method for the General Integral Control and a new integral control strategy along with a class of fire-new integrator. By using the linear system theory and Lyapunov method along with LaSalle’s invariance principle, the conditions on the control gains to ensure regionally as well as semi-globally asymptotic stability are provided. Theoretical analysis and simulation results demonstrated that: by using this design method, General Integral Control can deal with nonlinearity and uncertainties of dynamics more effectively; the optimum response can be achieved in the whole control domain, even under uncertain payload and varying-time disturbances. This means that General Integral Control has strong robustness, fast convergence, good flexibility, and then makes the engineers design a high performance controller more easily.

The Metro Project Construction Safety Risk Managing System of GMC  [PDF]
Guangwu Liu, Fengxia Luo, Gang Zeng
Open Journal of Safety Science and Technology (OJSST) , 2014, DOI: 10.4236/ojsst.2014.41005
Abstract: Based on the international vulgate safety risk managing theory, the Guangzhou Metro Corporation (GMC) summarizes the standard system of safety risk management in metro rail transit project, integrating with criterion files about project on safety risk management promulgated by the Ministry of Housing and Urban-Rural Development of the People’s Republic of China (MOHURD), according to the project practice. The result of application indicated that this system, which has been popularized in several other Chinese cities, effectively guaranteed personnel and project safety, and promoted the safety risk managing level of project participators in the same time.
General Integral Control Design via Singular Perturbation Technique  [PDF]
Baishun Liu, Xiangqian Luo, Jianhui Li
International Journal of Modern Nonlinear Theory and Application (IJMNTA) , 2014, DOI: 10.4236/ijmnta.2014.34019
Abstract: This paper proposes a systematic method to design general integral control with the generic integrator and integral control action. No longer resorting to an ordinary control along with a known Lyapunov function, but synthesizing singular perturbation technique, mean value theorem, stability theorem of interval matrix and Lyapunov method, a universal theorem to ensure regionally as well as semi-globally asymptotic stability is established in terms of some bounded information. Its highlight point is that the error of integrator output can be used to stabilize the system, just like the system state, such that it does not need to take an extra and special effort to deal with the integral dynamic. Theoretical analysis and simulation results demonstrated that: general integral controller, which is tuned by this design method, has super strong robustness and can deal with nonlinearity and uncertainties of dynamics more forcefully.
Conventional and Added-Order Proportional Nonlinear Integral Observers  [PDF]
Baishun Liu, Xiangqian Luo, Jianhui Li
International Journal of Modern Nonlinear Theory and Application (IJMNTA) , 2014, DOI: 10.4236/ijmnta.2014.35023
Abstract: In this paper, a kind of fire new nonlinear integrator and integral action is proposed. Consequently, a conventional Proportional Nonlinear Integral (P_NI) observer and two kinds of added-order P_NI observers are developed to deal with the uncertain nonlinear system. The conditions on the observer gains to ensure the estimated error to be ultimate boundness, which shrinks to zero as the states and control inputs converge to the equilibrium point, are provided. This means that if the observed system is asymptotically stable, the estimated error dynamics is asymptotically stable, too. Moreover, the highlight point of this paper is that the design of nonlinear integral observer is achieved by linear system theory. Simulation results showed that under the normal and perturbed cases, the pure added-order P_NI observer can effectively deal with the uncertain nonlinearities on both the system dynamics and measured outputs.
Study on Phosphorus Characteristics in Sediments of Xiangxi Bay, China Three-Gorge Reservoir  [PDF]
Huajun Luo, Defu Liu, Yingping Huang
Journal of Environmental Protection (JEP) , 2015, DOI: 10.4236/jep.2015.64028
Abstract: To explore the environment influence of the sediments in Xiangxi Bay (China Three-Gorge Reservoir), spatial and temporal distribution characteristics of total phosphorus (TP), phosphorus fractions, dissolved total phosphorus (DTP) of pore water and overlying water in the sediments were investigated. In surveys, the sampling was undertaken from six sites of Xiangxi Bay on 29 March 2009 and 28 March 2010. TP contents ranged from 1111.29 mg/kg to 1941.29 mg/kg with the mean value of 1533.09 mg/kg in 2009 spring and 1600.48 mg/kg in 2010 spring. Five fractions of sedimentary phosphorus, including loosely sorbed phosphorus (NH4Cl-P), redox-sensitive phosphorus (BD-P), metal oxide bound phosphorus (NaOH-P), calcium bound phosphorus (HCl-P), and residual phosphorus (Res-P), were separately quantified. DTP of pore water and overlying water all have positive correlations with NH4Cl-P and BD-P, which indicated that NH4Cl-P and BD-P were the main fractions that can easily release phosphorus in the sediments of Xiangxi Bay.
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