The H_∞ performance analysis and controller design for linear networked control systems(NCSs) are presented.The NCSs are considered a linear continuous system with time-varying interval input delay by assuming that t...The H_∞ performance analysis and controller design for linear networked control systems(NCSs) are presented.The NCSs are considered a linear continuous system with time-varying interval input delay by assuming that the sensor is time-driven and the logic Zero-order-holder(ZOH) and controller are event-driven.Based on this model,the delay interval is divided into two equal subintervals for H_∞ performance analysis.An improved H_∞ stabilization condition is obtained in linear matrix inequalities(LMIs) framework by adequately considering the information about the bounds of the input delay to construct novel Lyapunov–Krasovskii functionals(LKFs).For the purpose of reducing the conservatism of the proposed results,the bounds of the LKFs differential cross terms are properly estimated without introducing any slack matrix variables.Moreover,the H_∞ controller is reasonably designed to guarantee the robust asymptotic stability for the linear NCSs with an H_∞ performance level γ.Numerical simulation examples are included to validate the reduced conservatism and effectiveness of our proposed method.展开更多
The online-monitoring methods for insulation performance of current transformers of 330-750 kV substation are analyzed and compared.The effectiveness and availability of each method are discussed.Main features,advanta...The online-monitoring methods for insulation performance of current transformers of 330-750 kV substation are analyzed and compared.The effectiveness and availability of each method are discussed.Main features,advantages and disadvantages of each method and its corresponding standard are also described.展开更多
According to a lot of practical data in Liujialiang Mine and reliability theory and result of computer simulation, operation regularity of fully mechanized sublevel caving mining production system in the condition of ...According to a lot of practical data in Liujialiang Mine and reliability theory and result of computer simulation, operation regularity of fully mechanized sublevel caving mining production system in the condition of gently inclined complicated geological structure and production shortcomings are found out and reliability of system and output of the working face are predicted finally.展开更多
The problems like cracking of the girder in the mid-span and the ever-increasing vertical deflection appear during the long term usage of the long-span continuous rigid-flame bridge. Post-tension tendon with re- serve...The problems like cracking of the girder in the mid-span and the ever-increasing vertical deflection appear during the long term usage of the long-span continuous rigid-flame bridge. Post-tension tendon with re- served duct can increase the pre-stress of the main beam effectively, and decrease the long term span deflection in order to improve the performance of the girder. At the same time, the proper tension position is very crucial to optimise the stress distribution of the bridge and control the deflection increase. Combining with practical en- gineering, the authors analyze the influence of different positions of post-tension tendon （ including top-, web- and bottom plate tendons） on the stress and deflection of the main beam, and find out the optimal position of post tendon.展开更多
Parameters of the power source used to control PV-10 piezoelectric crystal valve are following DC output voltage： 0 - 120 V, continuously controllable, linear enlargement factor of input direct current voltage： appr...Parameters of the power source used to control PV-10 piezoelectric crystal valve are following DC output voltage： 0 - 120 V, continuously controllable, linear enlargement factor of input direct current voltage： approximate 25 times, the accuracy of DC output voltage： ±5%, manual control and automatic control.展开更多
During five-axis machining of impeller, the excessive local interference avoidance leads to inconsistency of cutter posture, low quality of machined surface and increase of processing time. Therefore, in order to impr...During five-axis machining of impeller, the excessive local interference avoidance leads to inconsistency of cutter posture, low quality of machined surface and increase of processing time. Therefore, in order to improve the efficiency of five-axis machining of impellers, it is necessary to minimize the cutter posture changes and create a continuous tool path while avoiding interference. By using an MC-space algorithm for interference avoidance, an MB-spline algorithm for continuous control was intended to create a five-axis machining tool path with excellent surface quality and economic feasibility. A five-axis cutting experiment was performed to verify the effectiveness of the continuity control. The result shows that the surface shape with continuous method is greatly improved, and the surface roughness is generally favorable. Consequently, the effectiveness of the suggested method is verified by identifying the improvement of efficiency of five-axis machining of an impeller in aspects of surface quality and machining time.展开更多
With the commencement of the 21st century, the information age, knowledge economy and integration of information and knowledge among production factors, organizations show increasing interest in knowledge management. ...With the commencement of the 21st century, the information age, knowledge economy and integration of information and knowledge among production factors, organizations show increasing interest in knowledge management. Managers are trying not only to preserve knowledge and transfer it efficiently within their organization, but also to ensure that it is not lost when a knowledge employee leaves the organization. Therefore, it is indispensable for organizations to monitor, record, transfer and preserve their knowledge. In order to ensure efficient preservation of knowledge by the organization, it is essential to integrate the area of the so-called knowledge continuity into the general management and ensure its maximum value. The goal of the article is to identify the role of control in the transformation process and its impact on ensuring knowledge continuity within the organization. A partial goal lies in identifying output quality control by means of productivity One of the conclusions of the article is that in today＇s economic situation, ignoring the existence of knowledge continuity could result in a crisis of management of knowledge and its loss.展开更多
Planning and implementation as well as increased control over the Business Continuity Management （BCM） is a complex task in the company requiring adequate resources. BCM aims to reduce risks and develops plans for r...Planning and implementation as well as increased control over the Business Continuity Management （BCM） is a complex task in the company requiring adequate resources. BCM aims to reduce risks and develops plans for restoring business activities if they are interrupted by a disaster. The purpose of the paper is to analyze and describe two standards, Information Technology Infrastructure Library （ITIL） and Control Objectives for Information and Related Technology （COBIT）, especially their mapping for the improved planning and implementation of the BCM as well as the increased control over the BCM activities. COBIT is used more as a management framework, providing management tools, such as control objectives, metrics and maturity models in order to complement the control framework. ITIL includes process steps and tasks because it is more oriented towards IT processes （process framework）, defining the best practice for IT service management. Within this mapping, ITIL processes may be used to achieve and demonstrate compliance with COBIT control objectives for BCM process.展开更多
The conditions for G1 continuity between two adjacent bicubic B-spline surfaces with double interior knots along their common boundary curve are obtained in this paper, which are directly represented by the control po...The conditions for G1 continuity between two adjacent bicubic B-spline surfaces with double interior knots along their common boundary curve are obtained in this paper, which are directly represented by the control points of the two B-spline surfaces. As stated by Shi Xi-quan and Zhao Yan, a local scheme of constructing G1 continuous B-spline surface models with single interior knots does not exist; we may achieve a local scheme of (true) G1 continuity over an arbitrary B-spline surface network using these conditions.展开更多
The authors concern robust model predictive control for linear continuous systems with polytopic uncertainties and input constraints. At each sampling time, a piecewise constant control sequence is obtained by solving...The authors concern robust model predictive control for linear continuous systems with polytopic uncertainties and input constraints. At each sampling time, a piecewise constant control sequence is obtained by solving a set of linear matrix inequalities. The sufficient conditions on the existence of the model predictive control are given, and the robust stability of the closed-loop systems is guaranteed. A simulation example illustrates the efficiency of the proposed method.展开更多
This work presents the nonlinear dynamical system of continuous fermentation from glycerol to 1,3-propanediol. The impulsive control scheme of continuous culture is intro- duced. By employing impulsive control, Lyapu...This work presents the nonlinear dynamical system of continuous fermentation from glycerol to 1,3-propanediol. The impulsive control scheme of continuous culture is intro- duced. By employing impulsive control, Lyapunov＇s method and comparison technique, sufficient conditions are established for the asymptotical stability and synchronization of the dynamical system of continuous fermentation. The upper bound of the impulse interval is also estimated. An example will illustrate the effectiveness of the results in Sec. 4.展开更多
基金Project (61304046) supported by the National Natural Science Funds for Young Scholar of ChinaProject (F201242) supported by Natural Science Foundation of Heilongjiang Province,China
文摘The H_∞ performance analysis and controller design for linear networked control systems(NCSs) are presented.The NCSs are considered a linear continuous system with time-varying interval input delay by assuming that the sensor is time-driven and the logic Zero-order-holder(ZOH) and controller are event-driven.Based on this model,the delay interval is divided into two equal subintervals for H_∞ performance analysis.An improved H_∞ stabilization condition is obtained in linear matrix inequalities(LMIs) framework by adequately considering the information about the bounds of the input delay to construct novel Lyapunov–Krasovskii functionals(LKFs).For the purpose of reducing the conservatism of the proposed results,the bounds of the LKFs differential cross terms are properly estimated without introducing any slack matrix variables.Moreover,the H_∞ controller is reasonably designed to guarantee the robust asymptotic stability for the linear NCSs with an H_∞ performance level γ.Numerical simulation examples are included to validate the reduced conservatism and effectiveness of our proposed method.
基金Science and Technology Projects of Gansu Electric Power Company(No.52274514005W)
文摘The online-monitoring methods for insulation performance of current transformers of 330-750 kV substation are analyzed and compared.The effectiveness and availability of each method are discussed.Main features,advantages and disadvantages of each method and its corresponding standard are also described.
文摘According to a lot of practical data in Liujialiang Mine and reliability theory and result of computer simulation, operation regularity of fully mechanized sublevel caving mining production system in the condition of gently inclined complicated geological structure and production shortcomings are found out and reliability of system and output of the working face are predicted finally.
文摘The problems like cracking of the girder in the mid-span and the ever-increasing vertical deflection appear during the long term usage of the long-span continuous rigid-flame bridge. Post-tension tendon with re- served duct can increase the pre-stress of the main beam effectively, and decrease the long term span deflection in order to improve the performance of the girder. At the same time, the proper tension position is very crucial to optimise the stress distribution of the bridge and control the deflection increase. Combining with practical en- gineering, the authors analyze the influence of different positions of post-tension tendon （ including top-, web- and bottom plate tendons） on the stress and deflection of the main beam, and find out the optimal position of post tendon.
文摘Parameters of the power source used to control PV-10 piezoelectric crystal valve are following DC output voltage： 0 - 120 V, continuously controllable, linear enlargement factor of input direct current voltage： approximate 25 times, the accuracy of DC output voltage： ±5%, manual control and automatic control.
基金Work supported by the Second Stage of Brain Korea 21 ProjectsProject(RTI04-01-03) supported by the Regional Technology Innovation Program of the Ministry of Knowledge Economy (MKE) of Korea
文摘During five-axis machining of impeller, the excessive local interference avoidance leads to inconsistency of cutter posture, low quality of machined surface and increase of processing time. Therefore, in order to improve the efficiency of five-axis machining of impellers, it is necessary to minimize the cutter posture changes and create a continuous tool path while avoiding interference. By using an MC-space algorithm for interference avoidance, an MB-spline algorithm for continuous control was intended to create a five-axis machining tool path with excellent surface quality and economic feasibility. A five-axis cutting experiment was performed to verify the effectiveness of the continuity control. The result shows that the surface shape with continuous method is greatly improved, and the surface roughness is generally favorable. Consequently, the effectiveness of the suggested method is verified by identifying the improvement of efficiency of five-axis machining of an impeller in aspects of surface quality and machining time.
文摘With the commencement of the 21st century, the information age, knowledge economy and integration of information and knowledge among production factors, organizations show increasing interest in knowledge management. Managers are trying not only to preserve knowledge and transfer it efficiently within their organization, but also to ensure that it is not lost when a knowledge employee leaves the organization. Therefore, it is indispensable for organizations to monitor, record, transfer and preserve their knowledge. In order to ensure efficient preservation of knowledge by the organization, it is essential to integrate the area of the so-called knowledge continuity into the general management and ensure its maximum value. The goal of the article is to identify the role of control in the transformation process and its impact on ensuring knowledge continuity within the organization. A partial goal lies in identifying output quality control by means of productivity One of the conclusions of the article is that in today＇s economic situation, ignoring the existence of knowledge continuity could result in a crisis of management of knowledge and its loss.
文摘Planning and implementation as well as increased control over the Business Continuity Management （BCM） is a complex task in the company requiring adequate resources. BCM aims to reduce risks and develops plans for restoring business activities if they are interrupted by a disaster. The purpose of the paper is to analyze and describe two standards, Information Technology Infrastructure Library （ITIL） and Control Objectives for Information and Related Technology （COBIT）, especially their mapping for the improved planning and implementation of the BCM as well as the increased control over the BCM activities. COBIT is used more as a management framework, providing management tools, such as control objectives, metrics and maturity models in order to complement the control framework. ITIL includes process steps and tasks because it is more oriented towards IT processes （process framework）, defining the best practice for IT service management. Within this mapping, ITIL processes may be used to achieve and demonstrate compliance with COBIT control objectives for BCM process.
基金973 Foundation of China (G19980306007) National Natural Science Foundation of China (G1999014115, 60473108) Outstanding Young Teacher Foundation of Educational Department of China (60073038) Doctoral Program Foundation of Educational Department of China.
文摘The conditions for G1 continuity between two adjacent bicubic B-spline surfaces with double interior knots along their common boundary curve are obtained in this paper, which are directly represented by the control points of the two B-spline surfaces. As stated by Shi Xi-quan and Zhao Yan, a local scheme of constructing G1 continuous B-spline surface models with single interior knots does not exist; we may achieve a local scheme of (true) G1 continuity over an arbitrary B-spline surface network using these conditions.
基金This research is supported by the National Natural Science Foundation of China under Grant No.60774016.
文摘The authors concern robust model predictive control for linear continuous systems with polytopic uncertainties and input constraints. At each sampling time, a piecewise constant control sequence is obtained by solving a set of linear matrix inequalities. The sufficient conditions on the existence of the model predictive control are given, and the robust stability of the closed-loop systems is guaranteed. A simulation example illustrates the efficiency of the proposed method.
文摘This work presents the nonlinear dynamical system of continuous fermentation from glycerol to 1,3-propanediol. The impulsive control scheme of continuous culture is intro- duced. By employing impulsive control, Lyapunov＇s method and comparison technique, sufficient conditions are established for the asymptotical stability and synchronization of the dynamical system of continuous fermentation. The upper bound of the impulse interval is also estimated. An example will illustrate the effectiveness of the results in Sec. 4.
