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Load frequency control in deregulated power system with wind integrated system using fuzzy controller

Yajvender Pal VERMA, Ashwani KUMAR

《能源前沿（英文）》 2013年 第7卷 第2期   页码 245-254 doi: 10.1007/s11708-012-0218-6

摘要： This paper presents the analysis of load frequency control (LFC) of a deregulated two-area hydro-thermal power system using fuzzy logic controller, with doubly fed induction generators (DFIGs) integrated into both the control areas. The deregulation of power sector has led to the formation of new companies for generation, transmission and distribution of power. The conventional two-area power system is modified to study the effects of the bilateral contracts of companies on the system dynamics. Deregulation creates highly competitive and distributed control environment, and the LFC becomes even more challenging when wind generators are also integrated into the system. The overall inertia of the system reduces, as the wind unit does not provide inertia and isolates from the grid during disturbances. The DFIGs integrated provide inertial support to the system through modified inertial control scheme, and arrests the initial fall in frequency after disturbance. The inertial control responds to frequency deviations, which takes out the kinetic energy of the wind turbine for improving the frequency response of the system. To enhance the participation of the doubly fed induction generator (DFIG) in the frequency control, optimal values of the speed control parameters of the DFIG-based wind turbine have been obtained using integral square error (ISE) technique. The dynamics of the system have been obtained for a small load perturbation, and for contract violation using fuzzy controller.

关键词： frequency regulation     fuzzy controller     de-regulated power system     doubly fed induction generator (DFIG)     bilateral contract    

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Demand response based congestion management in a mix of pool and bilateral electricity market model

Ashwani KUMAR, Charan SEKHAR

《能源前沿（英文）》 2012年 第6卷 第2期   页码 164-178 doi: 10.1007/s11708-012-0187-9

摘要： The independent system operator (ISO) is a key element in the deregulated structure with one of the responsibilities of transmission congestion management (CM). The ISO opts market based solutions to manage congestion receiving bids from generation companies (GENCOs) as well as distribution companies (DISCOMs) to reschedule their generation and relocate demand. The nodal prices increases during the congestion hours and the demand response to nodal prices will be an effective tool for the control of congestion. In this paper, demand response-based CM has been proposed for a mix of pool and bilateral electricity market model. The linear bid curves have been considered for demand bids to respond to the congestion in the network. The bilateral demand has been obtained with minimum deviations in their preferred schedule. The impact of flexible alternating current transmission system (FACTS) devices viz static var compensator (SVC) and thyristor controlled series compensator (TCSC) has also been considered for demand management during congestion. Multi-line congestion cases have been considered to study the impact on demand response without and with FACTS devices. The proposed approach has been tested on the IEEE 24 bus test system.

关键词： bid function     congestion management (CM)     demand response     pool+bilateral electricity market     static var compensator (SVC)     thyristor controlled series compensator (TCSC)    

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Dynamic simulation of urban water metabolism under water environmental carrying capacity restrictions

Weihua ZENG,Bo WU,Ying CHAI

《环境科学与工程前沿（英文）》 2016年 第10卷 第1期   页码 114-128 doi: 10.1007/s11783-014-0669-6

摘要： A revised concept for urban water metabolism (UWM) is presented in this study to address the inadequacies in current research on UWM and the problems associated with the traditional urban water metabolic process. Feedback loops can be analyzed to increase the water environmental carrying capacity (WECC) of the new urban water metabolism system (UWMS) over that of a traditional UWMS. An analysis of the feedback loops of an UWMS was used to construct a system dynamics (SD) model for the system under a WECC restriction. Water metabolic processes were simulated for different scenarios using the Tongzhou District in Beijing as an example. The results for the newly developed UWM case showed that a water environment of Tongzhou District could support a population of 1.1926 × 10 , an irrigation area of 375.521 km , a livestock of 0.7732 × 10 , and an industrial value added of ¥193.14 × 10 (i.e. about US$28.285× 10 ) in 2020. A sensitivity analysis showed that the WECC could be improved to some extent by constructing new sewage treatment facilities or by expanding the current sewage treatment facilities, using reclaimed water and improving the water circulation system.

关键词： urban water metabolism system (UWMS)     system dynamic simulation     water environmental carrying capacity (WECC)     feedback loops     bilateral control    

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Numerical investigation on the dryout point of annular flow in the upward narrow annuli with bilateral

SU Guanghui, QIU Suizheng, DUAN Feng, XIAO Zejun, HUANG Yanping

《能源前沿（英文）》 2007年 第1卷 第3期   页码 264-272 doi: 10.1007/s11708-007-0037-3

摘要： Based on the fundamental conservation principles—the mass, momentum, and energy conservation equtions of liquid films and the momentum conservation equation of vapor core, a theoretical three-fluid model has been developed to predict the dryout point of upward annular flow in vertical narrow annuli with bilateral heating. The range of the parameters are: pressure from 0.5 to 5.0 MPa; mass flow rate from 30 to 150 kg/(m · s); gap size from 1.2 to 2.0 mm. Through numerically solving the model, the relationships among the parameters of the critical quality (), critical heat flux (), mass flow rate, system pressure, and the ratio of heat flux on the inner wall of the outer tube to that on the outer wall of the inner tube (/) are obtained and analyzed. The predicted results accurately match with the experimental data. For a fixed , will increase with the decreases in the gap size and the tube curvature when the dryout point occurs on the outer wall of the inner tube. However, for a fixed , when the dryout point occurs on the inner wall of the outer tube, the parametric trend is reverse. When the dryout point on the inner and outer walls occurs simultaneously, reaches a peak value, and the ratio of / at this position changes with the gap size and the tube curvature.
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Prevention of laryngeal webs through endoscopic keel placement for bilateral vocal cord lesions

null

《医学前沿（英文）》 2018年 第12卷 第3期   页码 301-306 doi: 10.1007/s11684-017-0549-0

摘要：

Transoral microresection for treatment of vocal cord lesions involving the anterior commissure may result in anterior glottic webs. In this study, we retrospectively reviewed 54 patients who underwent microsurgery for bilateral lesions involving the anterior commissure and categorized them into two groups. The keel placement and control groups received endoscopic keel placement and mitomycin C, respectively. During the follow-up of at least 1 year, the laryngeal web formation rate significantly decreased in the keel placement group compared with that in the control group (18.6% versus 54.5%, <0.05). Furthermore, the voice handicap index-10 scores for patients without web formation decreased in both the keel placement and control groups ( <0.0001 and <0.001, respectively). A pseudomembrane covering the vocal cords was detected in 16.3% (7 of 43) cases after keel removal. A total of 100% (7 of 7) of these cases and 2.8% (1 of 36) of the other cases formed laryngeal webs ( <0.0001). Endoscopic keel placement could be an effective method for preventing anterior glottic webs after surgery for bilateral vocal cord diseases involving the anterior commissure. The pseudomembrane observed at the time of keel removal may imply a high risk of web formation.

关键词： glottic stenosis     glottic web     laryngeal keel     silastic sheets     anterior commissure    

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Crack propagation with different radius local random damage based on peridynamic theory

《结构与土木工程前沿（英文）》 2021年 第15卷 第5期   页码 1238-1248 doi: 10.1007/s11709-021-0695-y

摘要： Drawing from the advantages of Classical Mechanics, the peridynamic theory can clarify the crack propagation mechanism by an integral solution without initially setting the factitious crack and crack path. This study implements the peridynamic theory by subjecting bilateral notch cracked specimens to the conditions of no local damage, small radius local damage, and large radius local damage. Moreover, to study the effects of local stochastic damage with different radii on the crack propagation path and Y-direction displacement, a comparison and contact methodology was adopted, in which the crack propagation paths under uniaxial tension and displacement in the Y-direction were compared and analyzed. This method can be applied to steel structures under similar local random damage conditions.

关键词： peridynamics     stochastic damage     bilateral notch crack    

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Comparison of surgical indications for hysterectomy by age and approach in 4653 Chinese women

null

《医学前沿（英文）》 2014年 第8卷 第4期   页码 464-470 doi: 10.1007/s11684-014-0338-y

摘要：

Approximately one million hysterectomies are performed each year in China. However, national data regarding the indications and the surgical approaches for hysterectomy are lacking. The aim of this study was to examine the surgical indications for hysterectomy in different age groups and the relative merits of different surgical approaches for hysterectomy in Chinese women. Clinical data from 4653 cases of hysterectomy performed in Tongji Hospital from 2004 to 2009 were analysed. Hysterectomy was most commonly performed among women aged 40--49 years (2299; 49.4%). Overall, colporrhagia and abdominal pain were the two most common indications for hysterectomy. The most common indications by age groups were as follows: malignant ovarian tumour,<20 years; malignant uterine tumour, 20--29 and 30--39 years; uterine myoma, 40--49 and 50--59 years; and uterine prolapse, 60--69 and>70 years. The proportion of malignant aetiology also varied by age, being the highest in women aged<20 years (75.0%) and the lowest in those aged 40--49 years (19.9%). Approximately 35% women who had hysterectomies also had concomitant bilateral oophorectomy. The lowest rate of oophorectomy occurred in women aged 30--39 years (15.8%), whereas the highest rate was in those aged 50--59 years (75.9%). The abdominal surgical approach was used in 84% of all hysterectomies. Surgeries using the vaginal approach required a significantly shorter operating time (118 min average) than all other approaches (P<0.05). Both the amount of bleeding and the blood transfusion volume required were smaller in vaginal approaches, with no significant differences between the others. The surgical approaches used were also related to the scope of surgery. Both the surgical indications and the rates of bilateral oophorectomy varied by age. In terms of both operating time and the amount of bleeding and blood transfusion volume required, the vaginal approach was superior to all other surgical approaches.

关键词： hysterectomy     surgical indications     surgical approach     bilateral oophorectomy    

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Peridynamics versus XFEM: a comparative study for quasi-static crack problems

Jinhai ZHAO, Hesheng TANG, Songtao XUE

《结构与土木工程前沿（英文）》 2018年 第12卷 第4期   页码 548-557 doi: 10.1007/s11709-017-0434-6

摘要： Peridynamics (PD) is a nonlocal continuum theory based on integro-differential equations without spatial derivatives. The fracture criterion is implicitly incorporated in the PD theory and fracture is a natural outcome of the simulation. However, capturing of complex mixed-mode crack patterns has been proven to be difficult with PD. On the other hand, the extended finite element method (XFEM) is one of the most popular methods for fracture which allows crack propagation with minimal remeshing. It requires a fracture criterion which is independent of the underlying discretization though a certain refinement is needed in order to obtain suitable results. This article presents a comparative study between XFEM and PD. Therefore, two examples are studied. The first example is crack propagation in a double notched specimen under uniaxial tension with different crack spacings in loading direction. The second example is the specimens with two center cracks. The results show that PD as well as XFEM are well suited to capture this type of behaviour.

关键词： XFEM     peridynamic     bilateral crack     parallel double cracks     nonlocal theory    

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基于暗通道先验的单幅图像快速去雾算法 Research Articles

Bo-xuan YUE, Kang-ling LIU, Zi-yang WANG, Jun LIANG

《信息与电子工程前沿（英文）》 2019年 第20卷 第8期   页码 1109-1118 doi: 10.1631/FITEE.1700148

摘要： 在雾气中，可见光的散射降低了图像可见度。目前，去雾仍是图像处理应用的一个挑战。为实现去雾，提出一种基于单个像素的去雾加速算法。不同于基于区块的方法，所提方法分别估计每个区域的变换矩阵和大气光参数，其中加速的关键在于所有参数能在一次遍历中获得。然后，对传输映射进行双边过滤，恢复像素之间的关系。通过线性模糊模型恢复后，对恢复的图像进行调整，以提高对比度、光照强度和饱和度，尤其是补偿由相应波长引起的不同通道的光强误差。实验结果表明，该方法在处理速率方面优于已有的最先进去雾算法。与其他去雾方法比较和引入定量准则（峰信噪比、可检测边际速率、信息熵差）验证该方法有效。

关键词： 去雾；暗通道先验；雾图像模型；双边滤波    

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WHEAT STRIPE RUST AND INTEGRATION OF SUSTAINABLE CONTROL STRATEGIES IN CHINA

《农业科学与工程前沿（英文）》 2022年 第9卷 第1期   页码 37-51 doi: 10.15302/J-FASE-2021405

摘要：

Stripe (yellow) rust caused by Puccinia striiformis f. sp. tritici occurs in almost all wheat-producing regions of the world. Severe countrywide epidemics in China have caused substantial yield losses. Growing resistant cultivars is the best strategy to control this disease but the pathogen can overcome resistance in wheat cultivars. The high variation in the virulence of the pathogen combined with the large areas of susceptible wheat cultivars enables the pathogen population to increase rapidly and disperse over long distances under favorable environmental conditions, resulting in severe pandemics within cropping seasons. Current stripe rust control measures are based on many years of research including the underlying epidemiology regarding year-to-year survival of the pathogen, pathways of pathogen dispersal within seasons and years, the role of P. striiformis sexual hybridization, the use of resistance sources in breeding programs, and year-round surveillance of national wheat crops that are present in different parts of the country throughout the year. All these strategies depend on accurate prediction of epidemics, more precise use of fungicides to meet national requirements and better deployment of resistance genes. New ideas with potential application in sustainable protection of stripe rust include negative regulatory gene editing, resistance gene overexpression and biological control based on microbiomes.

 

关键词： sustainable disease control / integrated control Puccinia striiformis / Triticum aestivum    

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A systematic review of current and emergent manipulator control approaches

Syed Ali AJWAD,Jamshed IQBAL,Muhammad Imran ULLAH,Adeel MEHMOOD

《机械工程前沿（英文）》 2015年 第10卷 第2期   页码 198-210 doi: 10.1007/s11465-015-0335-0

摘要：

Pressing demands of productivity and accuracy in today’s robotic applications have highlighted an urge to replace classical control strategies with their modern control counterparts. This recent trend is further justified by the fact that the robotic manipulators have complex nonlinear dynamic structure with uncertain parameters. Highlighting the authors’ research achievements in the domain of manipulator design and control, this paper presents a systematic and comprehensive review of the state-of-the-art control techniques that find enormous potential in controlling manipulators to execute cutting-edge applications. In particular, three kinds of strategies, i.e., intelligent proportional-integral-derivative (PID) scheme, robust control and adaptation based approaches, are reviewed. Future trend in the subject area is commented. Open-source simulators to facilitate controller design are also tabulated. With a comprehensive list of references, it is anticipated that the review will act as a first-hand reference for researchers, engineers and industrial-interns to realize the control laws for multi-degree of freedom (DOF) manipulators.

关键词： robot control     robust and nonlinear control     adaptive control     intelligent control     industrial manipulators     robotic arm    

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Emerging contaminant control: From science to action

《环境科学与工程前沿（英文）》 2022年 第16卷 第6期 doi: 10.1007/s11783-022-1559-y

摘要： Since the concept of emerging contaminants (ECs) was first proposed in 2001, the global scientific research of ECs has developed rapidly. In the past decades, great progress has been achieved in the scientific research of ECs in China, including the establishment of EC analysis method system, the evaluation of the pollution status, pollution characteristics and environmental risk of ECs in typical regions of China, and establishment of EC control technology system. Continuous progress in scientific research of ECs promoted China’s action on EC control. It is planned that the environmental risk of ECs will be generally controlled by 2035 in China. Priority ECs should be screened for environmental management. Although great efforts have been made, the EC control in China still faces tremendous challenges. It is necessary to bridge the gap between scientific research and decision-making management. Based on the science and technology study, various measures such as engineering, policy management and public participation should be combinedly adopted for EC control.

关键词： Emerging contaminants     Priority pollutants     PPCPs     POPs     Control policy    

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An integrated approach for machine-learning-based system identification of dynamical systems under control: application towards the model predictive control of a highly nonlinear reactor system

《化学科学与工程前沿（英文）》 2022年 第16卷 第2期   页码 237-250 doi: 10.1007/s11705-021-2058-6

摘要： Advanced model-based control strategies, e.g., model predictive control, can offer superior control of key process variables for multiple-input multiple-output systems. The quality of the system model is critical to controller performance and should adequately describe the process dynamics across its operating range while remaining amenable to fast optimization. This work articulates an integrated system identification procedure for deriving black-box nonlinear continuous-time multiple-input multiple-output system models for nonlinear model predictive control. To showcase this approach, five candidate models for polynomial and interaction features of both output and manipulated variables were trained on simulated data and integrated into a nonlinear model predictive controller for a highly nonlinear continuous stirred tank reactor system. This procedure successfully identified system models that enabled effective control in both servo and regulator problems across wider operating ranges. These controllers also had reasonable per-iteration times of ca. 0.1 s. This demonstration of how such system models could be identified for nonlinear model predictive control without prior knowledge of system dynamics opens further possibilities for direct data-driven methodologies for model-based control which, in the face of process uncertainties or modelling limitations, allow rapid and stable control over wider operating ranges.

关键词： nonlinear model predictive control     black-box modeling     continuous-time system identification     machine learning     industrial applications of process control    

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Precision control system of two-DOF stage with linear ultrasonic motor

ZHANG Hanlei, SHI Yunlai, ZHAO Chunsheng

《机械工程前沿（英文）》 2008年 第3卷 第4期   页码 421-425 doi: 10.1007/s11465-008-0063-9

摘要： Using an appropriate control method, linear ultrasonic motors can be used in applications requiring high position accuracy. In this paper, a closed loop PI control system is designed to achieve high position accuracy during the control of a two-DOF stage driven by linear ultrasonic motors. Two ultrasonic motors are mounted on the stage to generate motion in two orthogonal directions. The PI control algorithm is used to increase the stability and accuracy of position control. The -axis mover covers 30 mm forward and backward in less than 0.3 s settling time and the -axis mover in less than 0.4 s. Experimental results denote that the control strategy proposed in this paper appears to have high efficiency, quick response, and high accuracy.

关键词： settling     position accuracy     PI control     control algorithm     orthogonal    

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A hybrid LQR-PID control design for seismic control of buildings equipped with ATMD

Amir Hossein HEIDARI, Sadegh ETEDALI, Mohamad Reza JAVAHERI-TAFTI

《结构与土木工程前沿（英文）》 2018年 第12卷 第1期   页码 44-57 doi: 10.1007/s11709-016-0382-6

摘要： This paper presents an efficient hybrid control approach through combining the idea of proportional-integral-derivative (PID) controller and linear quadratic regulator (LQR) control algorithm. The proposed LQR-PID controller, while having the advantage of the classical PID controller, is easy to implement in seismic-excited structures. Using an optimization procedure based on a cuckoo search (CS) algorithm, the LQR-PID controller is designed for a seismic- excited structure equipped with an active tuned mass damper (ATMD). Considering four earthquakes, the performance of the proposed LQR-PID controller is evaluated. Then, the results are compared with those given by a LQR controller. The simulation results indicate that the LQR-PID performs better than the LQR controller in reduction of seismic responses of the structure in the terms of displacement and acceleration of stories of the structure.

关键词： seismic control     tuned mass dampers     cuckoo search     PID controller     LQR controller    

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标题 作者 时间 类型 操作

Load frequency control in deregulated power system with wind integrated system using fuzzy controller

Yajvender Pal VERMA, Ashwani KUMAR

期刊论文

Demand response based congestion management in a mix of pool and bilateral electricity market model

Ashwani KUMAR, Charan SEKHAR

期刊论文

Dynamic simulation of urban water metabolism under water environmental carrying capacity restrictions

Weihua ZENG,Bo WU,Ying CHAI

期刊论文

Numerical investigation on the dryout point of annular flow in the upward narrow annuli with bilateral

SU Guanghui, QIU Suizheng, DUAN Feng, XIAO Zejun, HUANG Yanping

期刊论文

Prevention of laryngeal webs through endoscopic keel placement for bilateral vocal cord lesions

null

期刊论文

Crack propagation with different radius local random damage based on peridynamic theory

期刊论文

Comparison of surgical indications for hysterectomy by age and approach in 4653 Chinese women

null

期刊论文

Peridynamics versus XFEM: a comparative study for quasi-static crack problems

Jinhai ZHAO, Hesheng TANG, Songtao XUE

期刊论文

基于暗通道先验的单幅图像快速去雾算法

Bo-xuan YUE, Kang-ling LIU, Zi-yang WANG, Jun LIANG

期刊论文

WHEAT STRIPE RUST AND INTEGRATION OF SUSTAINABLE CONTROL STRATEGIES IN CHINA

期刊论文

A systematic review of current and emergent manipulator control approaches

Syed Ali AJWAD,Jamshed IQBAL,Muhammad Imran ULLAH,Adeel MEHMOOD

期刊论文

Emerging contaminant control: From science to action

期刊论文

An integrated approach for machine-learning-based system identification of dynamical systems under control: application towards the model predictive control of a highly nonlinear reactor system

期刊论文

Precision control system of two-DOF stage with linear ultrasonic motor

ZHANG Hanlei, SHI Yunlai, ZHAO Chunsheng

期刊论文

A hybrid LQR-PID control design for seismic control of buildings equipped with ATMD

Amir Hossein HEIDARI, Sadegh ETEDALI, Mohamad Reza JAVAHERI-TAFTI

期刊论文