Time filter

Source Type

Nanjing, China

Nanjing University of Finance & Economics , colloquially or is located in Nanjing, Jiangsu Province. The university specializes in financial and economic disciplines but also focuses on engineering, law, liberal arts, and science. Wikipedia.

Meng X.,Nanjing University of Finance and Economics
Journal of Manufacturing Systems | Year: 2010

To cope with the rapid change in manufacturing market requirements, reconfigurable manufacturing systems (RMSs) with the feature of reconfigurability, have to be developed. A model that describes the reconfiguring process of a manufacturing system is developed by applying colored timed object-oriented Petri nets. Based on the main difference between configurations of RMSs and flexible manufacturing systems (FMSs), a modular hierarchical structure of RMS is developed. By the object-oriented method, all the object classes in the RMS model are identified. A macro-place is used to model the aggregation of many processes and a macro-transition is used to link all the related macro-places. Macro-places and macro-transitions are connected with arcs to form a Petri net named a macro-level Petri net so that the control logic of RMS is represented. The macro-level Petri net is refined by hierarchical steps, each step describing these macro-places by more detailed sub macro-places until all the macro-places cannot be divided. Then the characteristics of material flow and time constraints in RMS are modeled by applying colored tokens and associated time-delay attributes. This model integrates object-oriented methods, stepwise refinement ideas and Petri nets together. The RMS activities can be encapsulated and modularized by the proposed method, so that RMS can be easily constructed and investigated by the system developers. © 2010 The Society of Manufacturing Engineers. Published by Elsevier Ltd. All rights reserved.

Hu S.,Huazhong University of Science and Technology | Yue D.,Huazhong University of Science and Technology | Liu J.,Nanjing University of Finance and Economics
Information Sciences | Year: 2012

This paper studies the H∞ filtering problem for a class of discrete-time networked systems with partly known distribution transmission delays. It is assumed that the random sensor-filter delay satisfies Markovian characteristics, but the transition probabilities of the delay transferring from one value to others are partly known. A novel measurement model is proposed to reflect the random delay of the transmission modes and the resulting filtering error system is modeled as a Markovian jump system (MJS) with multiple modes and state delay. Sufficient conditions are derived for the filtering error system to be stochastically stable and ensure a prescribed H∞ disturbance attenuation level bound by using mode-dependent Lyapunov functional approach. Based on the derived conditions, a design procedure for the H∞ filter is also presented. A numerical example is provided to show the design process of the filter and the effectiveness of the proposed method. © 2012 Elsevier Inc. All rights reserved.

Liu J.,Nanjing University of Finance and Economics | Yue D.,Nanjing University of Posts and Telecommunications
Journal of the Franklin Institute | Year: 2013

This paper is concerned with the event-based fault detection for the networked systems with communication delay and nonlinear perturbation. We propose an event-triggered scheme, which has some advantages over existing ones. The sensor data is transmitted only when the specified event condition involving the sampled measurements of the plant is violated. An event-based fault detection model is firstly constructed by taking the effect of event-triggered scheme and the network transmission delay into consideration. The main purpose of this paper is to design an event-based fault detection filter such that, for all unknown input, communication delay and nonlinear perturbation, the error between the residual signal and the fault signal is made as small as possible. Sufficient conditions for the existence of the desired fault detection filter are established in terms of linear matrix inequalities. Based on these conditions, the explicit expression is given for the designed fault detection filter parameters. A numerical example is employed to illustrate the advantage of the introduced event-triggered scheme and the effectiveness of the proposed method. © 2013 The Franklin Institute.

Liu J.,Nanjing University of Finance and Economics | Yue D.,Nanjing University of Posts and Telecommunications
Information Sciences | Year: 2013

This paper investigates the reliable control design for networked control system under event-triggered scheme. The key idea is that only the newly sampled sensor measurements that violate specified triggering condition will be transmitted to the controller, and the main attribute of our approach is that the proposed event-triggered scheme only needs a supervision of the system state in discrete instants and there is no need to retrofit the existing system. Considering the effect of the network transmission delay, event-triggered scheme and probabilistic sensor or actuator fault with different failure rates, a new fault model is proposed. Based on the newly built model, criteria for the exponential stability and criteria for co-designing both the feedback and the trigger parameters are derived by using Lyapunov functional. These criteria are obtained in the form of linear matrix inequalities. A simulation example is employed to show the effectiveness of the proposed method. © 2013 Elsevier Inc. All rights reserved.

Qiu Y.,Nanjing University of Finance and Economics
Journal of Non-Newtonian Fluid Mechanics | Year: 2013

Similar to the treatment of self-propelled particles, a generalized car following model with multiple look-ahead was utilized for the study of vehicular traffic. With the assumption of no skewness in velocity distribution and through iterative procedure, it is possible to construct a second order nonlocal hydrodynamic model. In contrast with two-phase fluid-dynamic models with a fundamental diagram, the model has the advantage of microscopically determined relaxation time parameters. Although the rigor is reduced a little compared with the Navier-Stokes like traffic flow model previously studied, the phase transition from free flow to synchronized flow, then from synchronized flow to wide moving jam is reproduced. The catch effect of synchronized flow is also revealed. The simulations suggest that the nonlocality in relaxation time and steady velocity, even though without nonlocality in viscocity, i.e., velocity variance, gives another explanation of synchronized flow. © 2013 Elsevier B.V.

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