The design of networked distributed sliding mode controllers with non-ideal links

In this paper, a methodology is proposed for the design of Networked Distributed Sliding Mode Controllers (NDSMC) for large-scale systems consisting of interconnected discrete-time subsystems. The state of each of these subsystems has time varying delays and there is also delay and packet loss in their interconnection links. The Networked Distributed Control System (NDCS), which is subject to the non-idealities of these interconnection links, is modeled and a Linear Matrix Inequality (LMI) based sufficient condition for designing asymptotically stable sliding surfaces, as well as the stabilizing NDSMC, is proposed. Finally, the proposed NDSMC structure is employed for the formation control of Unmanned Aerial Vehicles (UAVs); in which five vehicles are flying in a leader–follower architecture, in two platoons, whilst attempting to maintain the desired speed with a constant desired Euclidean distance between successive vehicles despite the presence of external perturbations such as wind disturbances.     

Pole placement LMI constraints for stability and transient performance of LPV systems with incomplete state measurement

In this paper, new conditions for the stabilisation and transient performance improvement of linear parameter-varying (LPV) systems considering the gain-scheduling (GS) strategy are proposed. Our work is focused on dealing with LPV systems under the major practical constraint of incomplete state measurement. In that sense, we propose two new control design strategies based on linear matrix inequalities (LMI). First, for coping with the general case where only a subset of the state variables is measured, we propose a new static output feedback (SOF) strategy. Second, for dealing with the particular case where only accelerometers signals are available, we bring new synthesis conditions for the design of state derivative feedback (SDF) controllers. Further from stability, our proposed methods are able to induce better transient response by including pole placement LMI constraints in the control design. For illustrating our contribution efficacy, we present a couple of design examples.     

数据驱动的产业集群产品布局设计方法研究

为了有效避免产业集群企业之间盲目、无序的竞争以及产品同质化,完善产品布局设计格局,促进产业集群转型升级势在必行。为此,本文从产品结构性能、创新能力、价格以及空间创新密度四大维度构建一种数据驱动的产品布局设计方法。以产业集群数据资源为基础,运用聚类算法和文本挖掘技术构建产品设计决策模型,为产业集群产品的布局设计提供相应的辅助决策。以宁波注塑机产业集群为例,验证本文方法的有效性。     

Coalitional games for networked controllers with constraints on semivalues: A randomized design approach

In a networked control architecture, the semivalues of a coalitional game where the communication links are the players can be used to provide information regarding their relevance. The linear relationship between the characteristic function of the game and the semivalues can be exploited to impose constraints on the design of the corresponding networked controllers to promote or penalize the use of certain links considering their impact on the overall system performance. In previous works, this approach was restricted to small networks due to the combinatorial growth of the problem size with the number of links. This work proposes a method to mitigate this issue by performing a random sampling in the set of topologies, i.e., coalitions of links, and employing a mild bound to reflect the impact of nonsampled topologies in the calculations. The simulation results show that the proposed approach can lead to significant reductions in computation time with moderate loss of performance.     

关于工程设计的规范及广西冶金研究院工程设计的思考

广西冶金研究院做为广西唯一的省级冶金和有色金属综合性应用开发研究设计单位,要实现工程设计资质从专业乙级→行业乙级→行业甲级的发展,首先必须大力培养或招聘人才,尤其是各专业的国家注册工程师和有实际工作经验的工程师,只有建设好符合工程设计资质申报要求的科技队伍,才能提升资质平台;同时要走出去,深入工矿企业,开拓市场,承接更多业务,积累更多设计经验。把提升平台与开拓市场两手同时抓好,逐渐扩大影响力,树立品牌形象,力争三、五年内把广西冶金研究院建成较高水平的、有独具特色的行业科研设计单位。     

Lyapunov-based design of locally collocated controllers for semi-linear parabolic PDE systems

The design problem of collocated feedback controllers is addressed in this paper for a class of semi-linear distributed parameter systems described by parabolic partial differential equation (PDE), where a finite number of local actuators and sensors are intermittently distributed in space. A Lyapunov direct method for the exponential stability analysis of the resulting closed-loop system is first presented for the system, in which the first mean value theorem for integration and the Wirtinger's inequality are employed. The corresponding stabilization condition is then derived through the analysis result. Finally, the proposed design method is implemented on the feedback control of a fisher equation and its effectiveness is evaluated through simulation results.     

Multi-loop PID controllers design with reduced loop interactions based on a frequency-domain direct synthesis method

A novel direct synthesis (DS) method for simultaneous and non-iterative design of multi-loop PID controllers for stable multivariable processes is presented in this article. We deal with the specifications of the desired closed-loop dynamics, which is a critical design decision in the DS method, for designing multi-loop controllers. Control loop interactions in multi-loop control systems are usually undesirable but unavoidable due to inter-channel interactions of multivariable processes. The main feature of the method is that the multi-loop control design aims at reducing the interactions among loops. The proposed DS method specifies the design target in terms of the frequency response of the desired closed-loop transfer function (CLTF) and synthesizes the controllers in the frequency domain. We develop an approach to effectively specify the desired closed-loop frequency response to achieve improved control performance by minimizing the sum of the magnitude of the interactive parts in the desired CLTF matrix. With the desired closed-loop frequency response and a process model, the frequency response of an ideal multi-loop controller is synthesized and then approximated to a PID controller. We provide simulation studies of three industrial benchmark processes and a nonlinear quadruple tank system to illustrate the design result and performance of the proposed method and make comparisons with several existing methods. Our results prove the effectiveness of the frequency-domain DS method. The proposed multi-loop PID controllers achieve reduced loop interactions and provide satisfactory overall performance.     

Evaluation of the clinical chemistry tests analytical performance with Sigma Metric by using different quality specifications - Comparison of analyser actual performance with manufacturer data

IntroductionThe interest in quality management tools/methodologies is gradually increasing to ensure quality and accurate results in line with international standards in clinical laboratories. Six Sigma stands apart from other methodologies with its total quality management system approach. However, the lack of standardization in tolerance limits restricts the advantages for the process. Our study aimed both to evaluate the applicability of analytical quality goals with Roche Cobas c 702 analyser and to determine achievable goals specific to the analyser used.Materials and methodsThe study examined under two main headings as Sigma_laboratory and Sigma_analyser. Sigma_laboratory was calculated using internal and external quality control data by using Roche Cobas c 702 analyser for 21 routine biochemistry parameters and, Sigma_analyser calculation was based on the manufacturer data presented in the package inserts of the reagents used in our laboratory during the study. Sigma values were calculated with the six sigma formula.ResultsConsidering the total number of targets achieved, Sigma_analyser performed best by meeting all CLIA goals, while Sigma_laboratory showed the lowest performance relative to biological variation (BV) desirable goals.ConclusionsThe balance between the applicability and analytical assurance of “goal-setting models” should be well established. Even if the package insert data provided by the manufacturer were used in our study, it was observed that almost a quarter of the evaluated analytes failed to achieve even “acceptable” level performance according to BV-based goals. Therefore, “state-of-the-art” goals for the Six Sigma methodology are considered to be more reasonable, achievable, and compatible with today’s technologies.     

A new data-driven process monitoring scheme for key performance indictors with application to hot strip mill process

Hot strip mill process (HSMP) plays a pivotal role in steel manufacturing industry, but involves significant complexity. Several faults could cause the decreasing evaluation of the key performance indicators (KPIs). Partial least squares (PLS) model has been popularly accepted for KPI-monitoring tasks, whereas some drawbacks have been reported such as high false alarm rate and strict limitation of Gaussian distribution. In this paper, a new scheme is designed without any distributional priority. The process information is extracted by the independent component analysis (ICA) and principal component analysis (PCA) one after another to obtain the Non-Gaussianity and Gaussianity rooted in process variables. Then the correlation canonical analysis (CCA), a classic tool of analyzing the correlation of two data sets, will be utilized to incorporate the process information and KPIs. Finally, two KPI-related indices are formed respectively, which are both bounded by key density estimation based approach. In the end, application of the new approach in a real steel plant will be demonstrated, where the comparison with PLS based results is covered.     

Direct synthesis-based controller design for integrating processes with time delay

Using the direct synthesis method, a PID controller in series with a lead/lag compensator is designed for control of open loop integrating processes with time delay. Set-point weighting is considered for reducing the undesirable overshoot. Guidelines are provided for selection of the desired closed loop tuning parameter in the direct synthesis method and set point weighting parameter. The method gives significant load disturbance rejection performances. Illustrative examples are considered to show the performances of the proposed method. Significant improvement is obtained when compared to recently reported methods.     

中国特色的政府绩效审计模式设计

随着我国服务型政府的确立,开展政府绩效审计,强化政府受托责任具有重要的现实意义.在剖析了我国推行绩效审计的制约因素基础上,提出从改革审计体制入手,建立问责和风险预警机制,从而构建具有中国特色的绩效审计模式.     

Robust estimator design with an emphasis balance between performance and robustness

From a number of ML estimators (typically unbiased) of practical interest which include the variance for a Gaussian distribution, the standard deviation for a Laplace distribution, the variance for a Rayleigh distribution and a “spread parameter” for a Cauchy distribution, we design robust estimators according to an emphasis balance between normalized performance and normalized robustness. We measure performance with inverted MSE and robustness with a differential geometric approach.     

Optimal tracking performance and design of networked control systems with packet dropouts

The optimal tracking problem for single-input–single-output (SISO) networked control system over a communication channel with packet dropouts is studied in this paper. The tracking performance is measured by the energy of the error signal between the output of the plant and the reference signal. It is shown that the optimal tracking performance is constrained by nonminimum phase zeros, unstable poles, the characteristics of the reference signal and packet dropout probability, and the optimal controller is obtained. It is also shown that when the communication constraint does not exist, the optimal tracking performance reduces to the existing normal tracking performance of the control system without a communication channel. The result shows how the packet dropouts probability of a communication channel may fundamentally constrain a control system's tracking ability. Some typical examples and simulations are given to illustrate the theoretical results.     

基于OLAP的高校学生综合成绩管理系统的设计与实现

文章结合学生综合成绩管理系统的特点,提出了基于OLAP技术的系统设计与实现。通过对学生综合成绩数据模型的建立和数据ETL过程,最后实现了对学生综合成绩的OLAP分析和展示,这对学校的学生管理能起到一定的决策支持。     

Co-design of an event-triggered dynamic output feedback controller for discrete-time LPV systems with constraints

This paper investigates an event-triggered control design approach for discrete-time linear parameter-varying (LPV) systems under control constraints. The proposed conditions can simultaneously design a parameter-dependent dynamic output feedback controller and an event generator, ensuring the closed-loop system’s regional asymptotic stability. Based on the Lyapunov stability theory, these conditions are given in terms of linear matrix inequalities (LMIs). Moreover, using some proposed optimization procedures, it is possible to minimize the number of sensor transmissions, maximize the estimation of the region of attraction of the origin, and incorporate optimal control criteria into the formulation. Through numerical examples, some comparisons with other approaches in the literature evidence the proposed technique’s efficacy.     

Direct design of recursive digital filters based on a new stability test

In this paper we present an alternative approach to the direct design of 1-D recursive digital filters satisfying prescribed magnitude specifications with or without constant group delay characteristic. This method uses an iterative method to calculate the coefficients of the filter's transfer function and guarantees the stability of the designed filter using a new stability test reported by Ramachandran and Gargour. To illustrate the usefulness of the technique, examples are given.     

Design of memory controllers for finite-time stabilization of delayed neural networks with uncertainty

In this paper, we investigate the problem of finite-time stabilization of time-varying delayed neural networks with uncertainty. By employing the Lyapunov approach and linear matrix inequalities (LMIs), two different memory controllers are derived to achieve the finite-time stabilization of the addressed neural networks. Moreover, the upper bound of the setting-time for stabilization can be estimated via different Lyapunov functions. Our results improve and extend some recent works. Finally, the effectiveness and feasibility of the proposed controllers are demonstrated by numerical simulations.     

Quality assessment of answers with user-identified criteria and data-driven features in social Q&A

The purpose of the current study is to identify the user criteria and data-driven features, both textual and non-textual, for assessing the quality of answers posted on social questioning and answering sites (social Q&A) across four different knowledge domains—Science, Technology, Art and Recreation. A comprehensive review of literature on quality assessment of information produced in social contexts was carried out to develop the theoretical framework for the current study. A total of 23 user criteria and 24 data features were proposed and tested with high-quality answers obtained from four social Q&A sites in Stack Exchange. Findings indicate that content-related criteria and user and review features were the most frequently used in quality assessments, while the importance of user criteria and data features was variable across the knowledge domains. In the Technology Q&A site containing mostly self-help questions, the utility class was the most frequently used group of criteria. The popularity of the socio-emotional class was more apparent in discussion-oriented topic categories such as Art and Recreation, where people seek others’ opinions or advice. Users of Art and Recreation Q&A sites in Stack Exchange appear to place more value on answerers’ efforts and time, good attitudes or manners, personal experience, and the same taste. The importance of user features and the emphasis on answerer's expertise on the Science Q&A site was observed. Examining the connection or gap between user quality criteria and data features across the knowledge domains could help to better understand users’ evaluation behaviors for their preferred answers, and identify the potential of social Q&A for user education/intervention in answer quality evaluation. This examination also offers practical guidance for designing more effective social Q&A platforms, considering how to customize community support systems, motivate contributions, and control content quality.