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A DDPG-based solution for optimal consensus of continuous-time linear multi-agent systems

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Science China(Technological Sciences) 2023年第8期66卷 2441-2453页

作者： LI Ye LIU ZhongXin LAN Ge sader malika CHEN ZengQiang College of Artificial Intelligence Nankai UniversityTianjin 300350China Tianjin Key Laboratory of Intelligent Robotics Nankai UniversityTianjin 300350China College of Software Nankai UniversityTianjin 300350China

Modeling a system in engineering applications is a time-consuming and labor-intensive task,as system parameters may change with temperature,component aging,*** this paper,a novel data-driven model-free optimal controller based on deep deterministic policy gradient(DDPG)is proposed to address the problem of continuous-time leader-following multi-agent *** deal with the problem of the dimensional explosion of state space and action space,two different types of neural nets are utilized to fit them instead of the time-consuming state iteration *** minimal energy consumption,the proposed controller achieves consensus only based on the consensus error and does not require any initial admissible ***,the controller is self-learning,which means it can achieve optimal control by learning in real time as the system parameters ***,the proofs of convergence and stability,as well as some simulation experiments,are provided to verify the algorithm’s effectiveness.

关键词： leader-following consensus optimal control reinforcement learning deep deterministic policy gradient(DDPG)

Exponential synchronization of neural networks with discontinuous activations

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Exponential synchronization of neural networks with disconti...

An Improvement of the Trajectory Segmented DDPC:Utilizing LQ Decomposition

第三十九届中国控制会议

作者： malika sader Fuyong Wang Zhongxin Liu Zengqiang Chen College of Artificial Intelligence Nankai University Tianjin Key Laboratory of Intelligent Robotics Nankai University

In this paper, we study the exponential synchronization of neural networks with discontinuous activations. Firstly, a useful discontinuous controller is constructed to ensure the exponential synchronization of considered neural networks. Secondly,some sufficient conditions are acquired according to the theory of differential inclusion and Lyapunov functional ***, one example is employed to show the flexibility of the results.

关键词： Discontinuous activations Discontinuous controller Neural networks Exponential synchronization

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An Improvement of the Trajectory Segmented DDPC:Utilizing LQ...

Leader-following attitude consensus control for multi-UUV systems with input constraints and error constraints

第43届中国控制会议

作者： Jingqian Yan malika sader Yucheng Li Zhongxin Liu College of Artificial Intelligence Nankai University Tianjin Key Laboratory of Interventional Brain-Computer Interface and Intelligent Rehabilitation Nankai University Department of Automation Tsinghua University

Behavioral systems theory has inspired the emergence of the data-driven predictive control methods(DDPC).These DDPC methods are influenced by non-causal terms,which are primarily responsible for the poor performance of systems in noisy *** the existing trajectory segmentation DDPC methods enforce causality,they increase the dimension of decision variables,resulting in computational *** address this problem,an improvement of trajectory segmentation DDPC utilizing LQ decomposition is proposed in this ***,the equivalence between the proposed DDPC and the existing DDPC is demonstrated in a noise-free *** proposed method decreases computational complexity and improves noise robustness by reducing decision variable dimensions and matching initial conditions *** in noisy conditions,the proposed DDPC method effectively solves problems without needing extra ***,the efficacy of the proposed method is shown through a numerical case study by varying parameters like noise level.

关键词： Data-driven predictive control trajectory segmentation LQ decomposition

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Leader-following attitude consensus control for multi-UUV sy...

Design of an Optical Water Pollution Sensor Using a Single-Layer Guided-Mode Resonance Filter

第40届中国控制会议

作者： Yunbiao Jiang Fuyong Wang sader malika Zengqiang Chen Feng Duan Zhongxin Liu College of Artificial Intelligence Nankai University Tianjin Key Laboratory of Intelligent Robotics Nankai University

In this paper, the problem of leader-following attitude consensus control for multi-UUV systems is investigated. From the perspective of application, practical issues such as input constraints and preset error constraints have been fully taken into consideration. Then, a novel distributed controller is designed, with the following three highlights:（i） the virtual velocity control strategy is proposed, and the dynamic surface control is applied to eliminate the complex derivation process of control variables and reduce the calculation load of controller;（ii） the hyperbolic tangent function is adopted into the design of dynamic control law to simulate the input constraint, and a Nussbaum function is introduced into the control law to avoid the risk of actuator damage caused by saturated control input;（iii） the controller designed based on barrier Lyapunov function and reverse recursive idea can not only guarantee the stability of the system, but also meet the performance requirements of preset error bound ***, simulation results fully illustrate the effectiveness of the designed controller.

关键词： Multi-UUV Systems Attitude Consensus Distributed Control Input Constraints Error Constraints

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Photonic Sensors 2013年第3期3卷 224-230页

作者： Edward sader Abdallah SAYYED-AHMAD Department of Physics Birzeit University Birzeit Palestine

The optical characteristics of a simple, planar, single layer, dielectric Mg-based guided mode resonance filter （GMRF） were investigated by means of rigorous-coupled wave analysis （RCWA）. This filter has great potential for real-life applications, especially as bio- and environmental sensors. The structure of the proposed sensor is compact, and all of its layers can be grown in a single process. In this paper, we present results on the design of a water pollution sensor in the violet region of the visible spectrum. The spectral and angular sensitivities of the sensor for both the transverse electric （TE） and transverse magnetic （TM） polarization modes were estimated and compared for various regions in the violet spectrum. A spectral response characterized with a narrow bandwidth and low reflection side bands was realized by carrying out extensive parameter search and optimization. Optimal spectral and angular sensitivities were found for the sensor with a grating thickness of 100nm in the TM polarized mode where we found them to be 100nm and 40 degrees, per index refraction unit, respectively.

关键词： Diffractive optics guided waves filters sensors spectral sensitivity angular sensitivity

Neoliberalism,Anti-Neoliberalism and Socialism

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学术界 2019年第2期 193-196页

作者： Emir sader State Universty of Rio de Janiero

Neoliberalism,Anti-Neoliberalism and

关键词： neoliberalism anti-neoliberalism alternative socialism Latin America

Analysis of the in vitro degradation and the in vivo tissue response to bi-layered 3D-printed scaffolds combining PLA and biphasic PLA/bioglass components--Guidance of the inflammatory response as basis for osteochondral regeneration

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Bioactive Materials 2017年第4期2卷 208-223页

作者： Mike Barbeck Tiziano Serra Patrick Booms Sanja Stojanovic Stevo Najman Elisabeth Engel Robert sader Charles James Kirkpatrick Melba Navarro Shahram Ghanaati Private Office BerlinGermany Institute for Bioengineering of Catalonia(IBEC) Biomaterials for Regenerative MedicineBarcelonaSpain Clinic of Oro-Maxillofacial and Plastic Surgery FORM-LabGoethe University FrankfurtFrankfurtGermany University of Ni's Faculty of MedicineDepartment for Cell and Tissue EngineeringInstitute of Biology and Human GeneticsNi'sSerbia Technical University of Catalonia(UPC) Dpt.Materials Science and MetallurgySpain CIBER en Bioingenieria Biomateriales y Nanomedicina(CIBER-BBN)Spain

The aim of the present study was the in vitro and in vivo analysis of a bi-layered 3D-printed scaffold combining a PLA layer and a biphasic PLA/bioglass G5 layer for regeneration of osteochondral defects in vivo Focus of the in vitro analysis was on the(molecular)weight loss and the morphological and mechanical variations after immersion in *** in vivo study focused on analysis of the tissue reactions and differences in the implant bed vascularization using an established subcutaneous implantation model in CD-1 mice and established histological and histomorphometrical *** scaffold parts kept their structural integrity,while changes in morphology were observed,especially for the PLA/G5 *** properties decreased with progressive degradation,while the PLA/G5 scaffolds presented higher compressive modulus than PLA *** tissue reaction to PLA included low numbers of BMGCs and minimal vascularization of its implant beds,while the addition of G5 lead to higher numbers of BMGCs and a higher implant bed *** revealed that the use of a bi-layered scaffold shows the ability to observe distinct in vivo response despite the physical proximity of PLA and PLA/G5 ***,the results showed that the addition of G5 enables to reduce scaffold weight loss and to increase mechanical ***,the addition of G5 lead to a higher vascularization of the implant bed required as basis for bone tissue regeneration mediated by higher numbers of BMGCs,while within the PLA parts a significantly lower vascularization was found optimally for chondral ***,this data show that the analyzed bi-layered scaffold may serve as an ideal basis for the regeneration of osteochondral tissue ***,the results show that it might be able to reduce the number of experimental animals required as it may be possible to analyze the tissue response to more than one implant in one experimental animal.

关键词： Bioactive glass Polylactic acid(PLA) Bi-layer scaffold Multinucleated giant cells Bone substitute Vascularization Calcium phosphate glass

Multimorbidity and clinical reasoning through the eyes of GPs:a qualitative study

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Family Medicine and Community Health 2021年第4期9卷 78-86,I0024-I0027页

作者： Claire Ritz Julia sader Sarah Cairo Notari Cedric Lanier Nathalie Caire Fon Mathieu Nendaz Marie-Claude Audétat Faculty of Medicine(IuMFE) University of GenevaGenevaSwitzerland Faculty of Medicine (UDREM)University of GenevaGenevaSwitzerland Faculty of Medicine Universitéde MontrealMontrealQuebecCanada

Objectives Despite the high prevalence of patients suffering from multimorbidity,the clinical reasoning processes involved during the longitudinal management are still *** study aimed to investigate what are the different characteristics of the clinical reasoning process clinicians use with patients suffering from multimorbidity,and to what extent this clinical reasoning differs from diagnostic *** Given the exploratory nature of this study and the difficulty general practitioners(GPs)have in expressing their reasoning,a qualitative methodology was therefore,*** Clinical reasoning Model described by Charlin et al was used as a framework to describe the multifaceted processes of the clinical *** Semistructured interviews were conducted with nine GPs working in an ambulatory setting in June to September 2018,in Geneva,*** Participants were GPs who came from public hospital or private *** interviews were transcribed verbatim and a thematic analysis was *** The results highlighted how some cognitive processes seem to be more specific to the management ***,the main goal is not to reach a diagnosis,but rather to consider several possibilities in order to maintain a balance between the evidence-based care options,patient’s priorities and maintaining quality of *** initial representation of the current problem seems to be more related to the importance of establishing links between the different pre-existing diseases,identifying opportunities for actions and trying to integrate the new elements from the patient’s context,rather than identifying the signs and symptoms that can lead to generating new clinical *** multiplicity of options to resolve problems is often perceived as difficult by ***,longitudinal management does not allow them to achieve a final resolution of problems and that requires continuous review and an ongoing prioritisation process.C

关键词： morbidity reasoning qualitative

Intraoperative Nerve Monitoring in Otolaryngology: A Survey of Clinical Practice Patterns

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International Journal of Otolaryngology and Head & Neck Surgery 2013年第1期2卷 21-26页

作者： Stephanie Flukes Shane S. Ling Travis Leahy Chady sader Fremantle Hospital Department of Ear Nose and Throat Surgery Perth Australia

Introduction: Intraoperative nerve monitoring is used in otolaryngology to assist in identification of nerves at risk. It is hoped that this will lead to lower rates of nerve injury. The objective of this study was to quantify the use of monitoring technology in current clinical practice. Method: An electronic survey was distributed to 376 registered fellows of the Australian Society of Head and Neck Surgery. Results: One-hundred and twenty-five responses were obtained. The majority of respondents report using monitoring at least some of the time during thyroid, parotid, and mastoid surgery (80%, 87%, and 73% respectively). Predictors of use include experience with intraoperative monitoring during training, and high caseloads in parotid surgery. Practice setting did not predict use. Conclusion: Despite equivocal evidence that intraoperative nerve monitoring is associated with a reduction in nerve injuries, this study demonstrates that the technology is widely used amongst otolaryngologists.

关键词： Monitoring Intraoperative Mastoid/Surgery Parotid Gland/Surgery Thyroid Gland/Surgery Physician’s Practice Patterns