The Experts below are selected from a list of 138 Experts worldwide ranked by ideXlab platform
Han Zhong-xu - One of the best experts on this subject based on the ideXlab platform.
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Design of main steam temperature control system of sub-critical 600MW power unit and its application
2008 Chinese Control and Decision Conference, 2008Co-Authors: Feng Jian, Han Zhong-xu, Kao Zhi-qiang, Dang Zeng-kui, Liang Zhen-wu, Xue Jian-hongAbstract:This paper presents a control system design scheme which combined the State Feedback based on the Increment Function Observer with PID, this design scheme has been successfully applied to a 600 MW boiler super-heater steam temperature control system. The control system could be in automation mode continually while the unit quickly changed its load up to 375 MW in succession, and it was taking an excellent control result which the biggest errors of two side main steam temperatures were less than 8degC and 10degC respectively. This case shows the theory of Increment Function Observer can be applied successfully in the thermal control engineering field, it provides an example for solving the control issue of the great inertia and the larger time lag controlled object such as boiler super-heater steam temperature control.
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The Sufficient and Necessary Conditions of Increment Function Observer
2006Co-Authors: Han Zhong-xuAbstract:The clue and foundation of theory research are presented for the new concept of Increment Function observer (IFO-KΔx)with a series of engineenng application.By summing up and disposing the phenomena observed,the sufficient and necessary condition of IFO-KΔx coming into existence is educed in this paper,and relative discussing and interpreting are given,which are more profound and combining practice.Meanwhile it is also proved that the condition H=TB is not considered in its sufficient and necessary conditions. Some engineering practices show that the Increment Function observer application in thermal control field can enhance automatic level of the big capacity power unit to a bran-new highness.
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SOME DESIGN CONCEPTS OF NONLINEAR STATE FEEDBACK CONTROL SYSTEM BASED ON IFO-K△x
2004Co-Authors: Han Zhong-xuAbstract:The Increment Function observer (IFO-K△x) can be able to used to design state feedback control system which controlled object has nonlinear characteristics and can be described by model of Hammerstein. It was certified by mathematical analysis that all of Luenberger Function observer, full dimension state observer and Increment state observer is special case of Increment Function observer under the different premises conditions. In this paper, starting from the close loop system of nonlinear control system effected under the state feedback control law based on Increment Function observer, several important concepts have been developed. Thus it is circumstantiated that controller and observer can be designed independently when using Increment Function observer to design state feedback control system which is nonlinear system based on model of Hammerstein. That is separate principle be the same with nonlinear system described in this paper. The theoretic foundation is established for using IFO- K△x in actual engineering of thermal control field.
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Application of state feedback based on Increment Function observer in generator units of power plant in China
2004 International Conference on Power System Technology 2004. PowerCon 2004., 1Co-Authors: Han Zhong-xu, Wang Yu-xue, Qu Yun, Zhang Shang-gangAbstract:Controlled object of generator unit is a nonlinear system. Based on the mechanism mathematical model of the unit plant, a type of Incremental mode observer IFO-K/spl Delta//sub x/ was described by state space in this paper. Subsequently, it has been proposed a new control method that state feedback based on IFO-K/spl Delta//sub x/ combined with conventional PID control. It can overcome the great inertia and the time lag of the boiler controlled object and improve response ability of unit load. At the same time the index of the stabilization was assured by using PID control. The practice has showed that the IFO-K/spl Delta//sub x/ has no strict requirement to mathematical model of controlled object. The observer designed has strong steady robustness especially being used in object with characteristics of great inertia and time lag. The control scheme has been applied in some 300 MW and 600 MW generator units of power plants in China. The excellent control result was acquired in boiler-turbine coordinated control system and main steam temperature control system. This control algorithm is brief, practical and easy to be spread.
Wenhua Dou - One of the best experts on this subject based on the ideXlab platform.
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general window based congestion control buffer occupancy network efficiency and packet loss
Conference on Communication Networks and Services Research, 2006Co-Authors: Lisong Shao, Heying Zhang, Wenhua DouAbstract:High speed networks with long distance present a unique environment where TCP have a problem under-utilizing the bandwidth of bottleneck link. To remedy this problem, many proposals, such as window-based mechanisms (HSTCP and STCP), rate-based ones (Fast TCP) and router-assistant ones (XCP), have been suggested. The recent researches show that the buffer size in routers heavily affects the performances of HSTCP, especially network efficiency. This paper studies the performances of general window-based mechanisms, such as buffer occupancy, network efficiency and packet loss. The study of buffer occupancy shows that large Increment Function and small buffer size will result in pseudo-congestion, from which HSTCP and slow start of TCP suffer, under-utilizing the capacity of bottleneck link. We propose asymptotic square increase (ASI) mechanism, whose Increment Function is an increase additive Function. Not to cause pseudo-congestion, a design principle of the buffer size of routers is given for the Increment Function of additive increase (AI), Multiplicative Increase (MI) and ASI. In this paper, the study of network efficiency shows that the concave increase mechanisms can obtain more network efficiency at smaller cost of packet loss than additive and convex ones.
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CNSR - General window-based congestion control: buffer occupancy, network efficiency and packet loss
4th Annual Communication Networks and Services Research Conference (CNSR'06), 1Co-Authors: Lisong Shao, Heying Zhang, Wenhua DouAbstract:High speed networks with long distance present a unique environment where TCP have a problem under-utilizing the bandwidth of bottleneck link. To remedy this problem, many proposals, such as window-based mechanisms (HSTCP and STCP), rate-based ones (Fast TCP) and router-assistant ones (XCP), have been suggested. The recent researches show that the buffer size in routers heavily affects the performances of HSTCP, especially network efficiency. This paper studies the performances of general window-based mechanisms, such as buffer occupancy, network efficiency and packet loss. The study of buffer occupancy shows that large Increment Function and small buffer size will result in pseudo-congestion, from which HSTCP and slow start of TCP suffer, under-utilizing the capacity of bottleneck link. We propose asymptotic square increase (ASI) mechanism, whose Increment Function is an increase additive Function. Not to cause pseudo-congestion, a design principle of the buffer size of routers is given for the Increment Function of additive increase (AI), Multiplicative Increase (MI) and ASI. In this paper, the study of network efficiency shows that the concave increase mechanisms can obtain more network efficiency at smaller cost of packet loss than additive and convex ones.
Edward A. Essock - One of the best experts on this subject based on the ideXlab platform.
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anisotropic local contrast normalization the role of stimulus orientation and spatial frequency bandwidths in the oblique and horizontal effect perceptual anisotropies
Vision Research, 2006Co-Authors: Bruce C. Hansen, Edward A. EssockAbstract:Abstract Visual ability for sine waves and other narrowband stimuli shows an oblique effect—worst performance at obliques, best at horizontal and vertical orientations. Recently, we have shown that with broadband stimuli (either 1/fα visual noise or natural scenes), performance for detecting oriented content is worst at horizontal, best at the obliques, and intermediate at vertical orientations (a “horizontal effect”). This horizontal effect has been explained by a cortical contrast normalization model that is both local (over orientation and spatial frequency) and anisotropic (due to a numerical bias of neurons with different preferred orientations). Here, the bandwidth of content at which an oblique effect or horizontal effect occurs was assessed in two suprathreshold matching experiments conducted with 1/fα noise stimuli filtered with a triangle Increment Function of varied bandwidth (16 levels of orientation and spatial frequency bandwidth). The results provided further support for the local anisotropic normalization model in that an oblique effect was observed when a fairly small range of orientations and high spatial frequencies were tested and the horizontal effect was observed for broadband Increments ⩾20° orientation bandwidth and ⩾1-octave in frequency. At intermediate spatial frequency and orientation Increment bandwidths, a blend of the two anisotropies was observed.
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Anisotropic local contrast normalization: the role of stimulus orientation and spatial frequency bandwidths in the oblique and horizontal effect perceptual anisotropies.
Vision research, 2006Co-Authors: Bruce C. Hansen, Edward A. EssockAbstract:Visual ability for sine waves and other narrowband stimuli shows an oblique effect--worst performance at obliques, best at horizontal and vertical orientations. Recently, we have shown that with broadband stimuli (either 1/f(alpha) visual noise or natural scenes), performance for detecting oriented content is worst at horizontal, best at the obliques, and intermediate at vertical orientations (a "horizontal effect"). This horizontal effect has been explained by a cortical contrast normalization model that is both local (over orientation and spatial frequency) and anisotropic (due to a numerical bias of neurons with different preferred orientations). Here, the bandwidth of content at which an oblique effect or horizontal effect occurs was assessed in two suprathreshold matching experiments conducted with 1/f(alpha) noise stimuli filtered with a triangle Increment Function of varied bandwidth (16 levels of orientation and spatial frequency bandwidth). The results provided further support for the local anisotropic normalization model in that an oblique effect was observed when a fairly small range of orientations and high spatial frequencies were tested and the horizontal effect was observed for broadband Increments > or = 20 degrees orientation bandwidth and > or = 1-octave in frequency. At intermediate spatial frequency and orientation Increment bandwidths, a blend of the two anisotropies was observed.
Lisong Shao - One of the best experts on this subject based on the ideXlab platform.
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general window based congestion control buffer occupancy network efficiency and packet loss
Conference on Communication Networks and Services Research, 2006Co-Authors: Lisong Shao, Heying Zhang, Wenhua DouAbstract:High speed networks with long distance present a unique environment where TCP have a problem under-utilizing the bandwidth of bottleneck link. To remedy this problem, many proposals, such as window-based mechanisms (HSTCP and STCP), rate-based ones (Fast TCP) and router-assistant ones (XCP), have been suggested. The recent researches show that the buffer size in routers heavily affects the performances of HSTCP, especially network efficiency. This paper studies the performances of general window-based mechanisms, such as buffer occupancy, network efficiency and packet loss. The study of buffer occupancy shows that large Increment Function and small buffer size will result in pseudo-congestion, from which HSTCP and slow start of TCP suffer, under-utilizing the capacity of bottleneck link. We propose asymptotic square increase (ASI) mechanism, whose Increment Function is an increase additive Function. Not to cause pseudo-congestion, a design principle of the buffer size of routers is given for the Increment Function of additive increase (AI), Multiplicative Increase (MI) and ASI. In this paper, the study of network efficiency shows that the concave increase mechanisms can obtain more network efficiency at smaller cost of packet loss than additive and convex ones.
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CNSR - General window-based congestion control: buffer occupancy, network efficiency and packet loss
4th Annual Communication Networks and Services Research Conference (CNSR'06), 1Co-Authors: Lisong Shao, Heying Zhang, Wenhua DouAbstract:High speed networks with long distance present a unique environment where TCP have a problem under-utilizing the bandwidth of bottleneck link. To remedy this problem, many proposals, such as window-based mechanisms (HSTCP and STCP), rate-based ones (Fast TCP) and router-assistant ones (XCP), have been suggested. The recent researches show that the buffer size in routers heavily affects the performances of HSTCP, especially network efficiency. This paper studies the performances of general window-based mechanisms, such as buffer occupancy, network efficiency and packet loss. The study of buffer occupancy shows that large Increment Function and small buffer size will result in pseudo-congestion, from which HSTCP and slow start of TCP suffer, under-utilizing the capacity of bottleneck link. We propose asymptotic square increase (ASI) mechanism, whose Increment Function is an increase additive Function. Not to cause pseudo-congestion, a design principle of the buffer size of routers is given for the Increment Function of additive increase (AI), Multiplicative Increase (MI) and ASI. In this paper, the study of network efficiency shows that the concave increase mechanisms can obtain more network efficiency at smaller cost of packet loss than additive and convex ones.
Zhu Neng-fei - One of the best experts on this subject based on the ideXlab platform.
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Application of Increment Function observer in steam temperature control of Wshape flame once-through boiler
2012Co-Authors: Zhu Neng-feiAbstract:The control of the W-shape flame supercritical once-through boiler has some features,which include that the overheated steam temperature control and the coal-water ratio control are strong coupled,the furnace temperature is too high and leads severe coking,the control object of the overheated steam temperature has larger lag and longer inertia time and others.Aiming at above features,the Increment Function observer and state feedback control were added into the overheated steam temperature cascade PID control system of the 2×600 MW unit in GongXian power plant.The practical commissioning and application show that the dynamic characteristics of the overheated steam temperature were significantly improved;and in the process of condition changing,the deviation of overheated steam temperature was controlled within the allowed range.The design scheme has better practical applicability and provides certain reference for supercritical units in steam temperature control.
