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Fault Accommodation for a Class of Nonlinear Uncertain Systems With Event-Triggered Input

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IEEE/CAA Journal of Automatica Sinica 2022年第2期9卷 235-245页

作者： Dong Zhao marios m.polycarpou IEEE KIOS Research and Innovation Center of Excellence and the Department of Electrical and Computer EngineeringUniversity of CyprusNicosia 1678Cyprus

The event-triggered fault accommodation problem for a class of nonlinear uncertain systems is considered in this *** control signal transmission from the controller to the system is determined by an event-triggering scheme with relative and constant triggering *** the event-induced control input error and system fault threat,a novel eventtriggered active fault accommodation scheme is designed,which consists of an event-triggered nominal controller for the time period before detecting the occurrence of faults and an adaptive approximation based event-triggered fault accommodation scheme for handling the unknown faults after detecting the occurrence of *** closed-loop stability and inter-event time of the proposed fault accommodation scheme are rigorously *** cases for the fault accommodation design under constant triggering threshold are also *** example is employed to illustrate the effectiveness of the proposed fault accommodation scheme.

关键词： Adaptive control event-triggered control fault accommodation neural networks nonlinear systems

Passive Attack Detection for a Class of Stealthy Intermittent Integrity Attacks

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IEEE/CAA Journal of Automatica Sinica 2023年第4期10卷 898-915页

作者： Kangkang Zhang Christodoulos Keliris Thomas Parisini Bin Jiang marios m.polycarpou Department of Electrical and Electronic Engineering Imperial College LondonLondon SW72AZUKand also with the KIOS Research and Innovation Center of ExcellenceUniversity of CyprusNicosia 1678Cyprus KIOS Research and Innovation Center of Excellence and the Department of Electrical and Computer Engineering University of CyprusNicosia 1678Cyprus Department of Electrical and Electronic Engineering Imperial College LondonLondon SW72AZUK Department of Engineering and Architecture University of TriesteTrieste 34127Italy KIOS Research and Innovation Center of Excellence University of CyprusNicosia 1678Cyprus College of Automation Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China

This paper proposes a passive methodology for detecting a class of stealthy intermittent integrity attacks in cyberphysical systems subject to process disturbances and measurement noise.A stealthy intermittent integrity attack strategy is first proposed by modifying a zero-dynamics attack *** stealthiness of the generated attacks is rigorously investigated under the condition that the adversary does not know precisely the system state *** order to help detect such attacks,a backward-in-time detection residual is proposed based on an equivalent quantity of the system state change,due to the attack,at a time prior to the attack occurrence time.A key characteristic of this residual is that its magnitude increases every time a new attack *** estimate this unknown residual,an optimal fixed-point smoother is proposed by minimizing a piece-wise linear quadratic cost function with a set of specifically designed weighting *** smoother design guarantees robustness with respect to process disturbances and measurement noise,and is also able to maintain sensitivity as time progresses to intermittent integrity attack by resetting the covariance matrix based on the weighting *** adaptive threshold is designed based on the estimated backward-in-time residual,and the attack detectability analysis is rigorously investigated to characterize quantitatively the class of attacks that can be detected by the proposed ***,a simulation example is used to demonstrate the effectiveness of the developed methodology.

关键词： Backward-in-time equivalent quantity fixed-point smoother intermittent integrity attacks

matrix pencil based robust control for feedforward systems with event-triggered communications and sensor/actuator faults

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Journal of Automation and Intelligence 2023年第3期2卷 139-145页

作者： Hefu Ye marios m.polycarpou Changyun Wen School of Electrical and Electronic Engineering Nanyang Technological UniversityNanyang Avenue639798Singapore Department of Electrical and Computer Engineering KIOS Center of ExcellenceUniversity of CyprusNicosia1678Cyprus

In this paper we address the issue of output-feedback robust control for a class of feedforward nonlinear *** different from the related literature,the feedback/input signals are corrupted by additive noises and can only be transmitted intermittently due to the consideration of event-triggered communications,which bring new challenges to the control *** the aid of matrix pencil based design procedures,regulating the output to near zero is globally solved by a non-conservative dynamic low-gain controller which requires only an a priori information on the upper-bound of the growth rate of *** analysis shows that the closed-loop system is input-to-state stable with respect to the sampled errors and additive *** particular,the observer and controller designs have a dual architecture with a single dynamic scaling parameter whose update law can be obtained by calculating the generalized eigenvalues of matrix pencils offline,which has an advantage in the sense of improving the system convergence rate.

关键词： Feedforward nonlinear systems Output-feedback Asynchronous event-triggered control Dynamic gain

Scalable Distributed Sensor Fault Diagnosis for Smart Buildings

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IEEE/CAA Journal of Automatica Sinica 2020年第3期7卷 638-655页

作者： Panayiotis m.Papadopoulos Vasso Reppa marios m.polycarpou Christos G.Panayiotou IEEE KIOS Research and Innovation Center of Excellence Department of Electrical and Computer EngineeringUniversity of CyprusNicosia 1678Cyprus Department of maritime and Transport Technology Delft University of TechnologyDelft2628 CDThe Netherlands

The enormous energy use of the building sector and the requirements for indoor living quality that aim to improve occupants' productivity and health, prioritize Smart Buildings as an emerging technology. The Heating, Ventilation and Air-Conditioning(HVAC) system is considered one of the most critical and essential parts in buildings since it consumes the largest amount of energy and is responsible for humans comfort. Due to the intermittent operation of HVAC systems, faults are more likely to occur, possibly increasing eventually building's energy consumption and/or downgrading indoor living quality. The complexity and large scale nature of HVAC systems complicate the diagnosis of faults in a centralized framework. This paper presents a distributed intelligent fault diagnosis algorithm for detecting and isolating multiple sensor faults in large-scale HVAC *** the HVAC system as a network of interconnected subsystems allows the design of a set of distributed sensor fault diagnosis agents capable of isolating multiple sensor faults by applying a combinatorial decision logic and diagnostic reasoning. The performance of the proposed method is investigated with respect to robustness, fault detectability and scalability. Simulations are used to illustrate the effectiveness of the proposed method in the presence of multiple sensor faults applied to a 83-zone HVAC system and to evaluate the sensitivity of the method with respect to sensor noise variance.

关键词： Building automation fault diagnosis fault location smart homes

Neoadjuvant treatment of pancreatic ductal adenocarcinoma:present and future

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Journal of Cancer metastasis and Treatment 2022年第1期8卷 174-196页

作者： Ioannis m.Koukourakis Dimitra Desse marios Papadimitriou manousos Konstadoulakis Anna Zygogianni Christos Papadimitriou Oncology Unit Aretaieio University HospitalNational and Kapodistrian University of AthensAthens 11528Greece Radiation Oncology Unit Aretaieio University HospitalNational and Kapodistrian University of AthensAthens 11528Greece Second Department of Surgery Aretaieio University HospitalNational and Kapodistrian University of AthensAthens 11528Greece

Pancreatic ductal adenocarcinoma is a highly aggressive malignancy with a poor *** treatment with acceptable outcomes is yet to be found,with chemo-and radioresistance comprising major impediments towards this *** upfront surgery is the established therapeutic approach for resectable and borderline resectable disease,neoadjuvant treatment has recently monopolized the interest in clinical *** also applies to locally advanced pancreatic adenocarcinomas that could potentially be rendered *** and chemoradiotherapy are the most utilized therapeutic modalities in the neoadjuvant setting,while immunotherapy and targeting agents have been gaining significant *** critical review focuses on the clinical experience gained from retrospective and phase II/III randomized trials,reporting on the outcomes of neoadjuvant chemotherapy and chemoradiotherapy for pancreatic ***,the ongoing trials,including those that involve immunotherapy and targeting agents,are summarized.

关键词： Pancreatic cancer neoadjuvant treatment chemotherapy radiotherapy surgery immunotherapy

Anharmonic electron-phonon coupling in ultrasoft and locally disordered perovskites

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npj Computational materials 2023年第1期9卷 744-756页

作者： marios Zacharias George Volonakis Feliciano Giustino Jacky Even Univ Rennes INSA RennesCNRSInstitut FOTON-UMR 6082F-35000 RennesFrance Univ Rennes ENSCRINSA RennesCNRSISCR-UMR 6226F-35000 RennesFrance Oden Institute for Computational Engineering and Sciences The University of Texas at AustinAustinTX 78712USA Department of Physics The University of Texas at AustinAustinTX 78712USA

Anharmonicity and local disorder(polymorphism)are ubiquitous in perovskite physics,inducing various phenomena observed in scattering and spectroscopy *** of these phenomena still lack interpretation from first principles since,hitherto,no approach is available to account for anharmonicity and disorder in electron–phonon ***,relying on the special displacement method,we develop a unified treatment of both and demonstrate that electron–phonon coupling is strongly influenced when we employ polymorphous perovskite *** uncover that polymorphism in halide perovskites leads to vibrational dynamics far from the ideal noninteracting phonon picture and drives the gradual change in their band gap around phase transition *** also clarify that combined band gap corrections arising from disorder,spin-orbit coupling,exchange–correlation functionals of high accuracy,and electron–phonon coupling are all *** findings agree with experiments,suggesting that polymorphism is the key to address pending questions on perovskites’technological applications.

关键词： perovskite phonon harmonic

Effects of an active lifestyle on the physical frailty of liver transplant candidates

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World Journal of Transplantation 2022年第11期12卷 365-377页

作者： Ilias marios Oikonomou Emmanouil Sinakos Nikolaos Antoniadis Ioannis Goulis Olga Giouleme maria Anifanti Georgios Katsanos Konstantina-Eleni Karakasi Georgios Tsoulfas Evangelia Kouidi Department of Transplant Surgery Aristotle University of ThessalonikiThessaloniki 54642Greece The Fourth Department of Internal medicine Aristotle University of ThessalonikiThessaloniki 54642Greece The Second Propaedeutic Department of Internal medicine Aristotle University of ThessalonikiThessaloniki 54642Greece Laboratory of Sports medicine Aristotle University of ThessalonikiThessaloniki 57001Greece

BACKGROUND Liver transplantation is the most important therapeutic intervention for end-stage liver disease(ELD).The prioritization of these patients is based on the model for end-stage liver disease(mELD),which can successfully predict short-term ***,despite its great validity and value,it cannot fully incorporate several comorbidities of liver disease,such as sarcopenia and physical frailty,variables that can sufficiently influence the survival of such ***,there is growing interest in the importance of physical frailty in regard to mortality in liver transplant candidates and recipients,as well as its role in improving their survival *** To evaluate the effects of an active lifestyle on physical frailty on liver transplant *** An observational study was performed within the facilities of the Department of Transplant Surgery of Aristotle University of *** liver transplant candidate patients from the waiting list of the department were included in the *** that were bedridden,had recent cardiovascular incidents,or had required inpatient treatment for more than 5 d in the last 6 mo were excluded from the *** following variables were evaluated:Activity level via the International Physical Activity Questionnaire(IPAQ);functional capacity via the 6-min walking test(6mWT)and cardiopulmonary exercise testing;and physical frailty via the Liver Frailty Index(LFI).RESULTS According to their responses in the IPAQ,patients were divided into the following two groups based on their activity level:Active group(A,10 patients);and sedentary group(S,10 patients).Comparing mean values of the recorded variables showed the following results:mELD(A:12.05±5.63 vs S:13.99±3.60;P>0.05);peak oxygen uptake(A:29.78±6.07 mL/kg/min vs S:18.11±3.39 mL/kg/min;PmL/kg/min vs S:13.96±1.45 mL/kg/min;PmWT(A:458.2±57.5 m vs S:324.7±55.8 m;P<0.001);and LFI(A:3.75±0.31 vs

关键词： Liver transplantation Frailty Six-minute walk test Cardiopulmonary exercise testing Exercise therapy Observational study

The Effect of Circuit Training on Resting Heart Rate Variability, Cardiovascular Disease Risk Factors and Physical Fitness in Healthy Untrained Adults

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Health 2016年第2期8卷 144-155页

作者： Adamos Vrachimis marios Hadjicharalambous Chris Tyler School of Human & Life Sciences Roehampton University London UK Department of Life & Health Sciences University of Nicosia Nicosia Cyprus

The purpose of the present study was to examine the effect of circuit training (CT) on resting heart rate variability (HRV) and other cardiovascular disease (CVD) risk factors such as blood lipids and blood glucose and on fitness components. Twenty-four healthy untrained adults (age 26.5 ± 5.1 years;height 1.67 ± 8.4 m;weight 66.8 ± 15.1 kg;26.3% ± 5.2%;maximum oxygen uptake (VO2max) 48.5 ± 10.0 ***-1.min-1) were assigned to either CT (n = 12) involving bodyweight exercises, or control (CON, n = 12) groups. Prior to the start and following the end of the six-week training period, time-, frequency-domain and nonlinear measures of resting HRV, arterial blood pressure, body composition, fasting blood lipids, lipoproteins and glucose, VO2max, upper body muscular endurance (UBmE) and abdominal and hip flexor (AHFmE), back strength (BS) and handgrip were assessed. None of the resting HRV measures (P > 0.05) were affected by the CT intervention. However, diastolic blood pressure decreased (P = 0.03), lean body weight (P = 0.03) increased, VO2max (P = 0.03), UBmE (P = 0.001), AHFmE (P = 0.04), and BS (P = 0.03) were significantly higher following CT, whereas the other variables were not influenced by the CT. Six-week of CT involving bodyweight exercises has no significant impact on resting HRV. However, this type of training might decrease the risk for development of CVD by reducing arterial blood pressure and by improving body composition, aerobic capacity, muscular endurance and strength.

关键词： Heart Rate Variability Circuit Training Healthy Untrained Adults

秸秆生物质炭DOm光谱特征及其与Cu^(2+)的相互作用

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中国环境科学 2021年第8期41卷 3714-3722页

作者：李婉秋施暖暖 marios Drosos 李恋卿潘根兴南京农业大学农业资源与生态环境研究所江苏南京210095

通过荧光猝灭滴定法探究玉米秸秆炭(mSB)、水稻秸秆炭(RSB)和花生秸秆炭(PSB)中DOm的光谱特征及其与Cu^(2+)的络合机理.结果表明:三种生物质炭的DOm均具有较高的亲水性和较低的芳香性,其中RSB-DOm的芳香性相对较强、分子量较大,但DOm含... 详细信息

通过荧光猝灭滴定法探究玉米秸秆炭(mSB)、水稻秸秆炭(RSB)和花生秸秆炭(PSB)中DOm的光谱特征及其与Cu^(2+)的络合机理.结果表明:三种生物质炭的DOm均具有较高的亲水性和较低的芳香性,其中RSB-DOm的芳香性相对较强、分子量较大,但DOm含量低,PSB-DOm含量最高,芳香结构中含氧官能团较多.mSB和RSB-DOm中均含类富里酸组分C1和类腐殖酸组分C3、C4,RSB-DOm中还有类色氨酸组分C5,PSB-DOm则由两种类富里酸组分C1、C2和较长波长类腐殖酸组分C4组成,3种DOm均以类富里酸组分为主,占比达54.93%~86.29%.Cu^(2+)与类腐殖酸组分的稳定常数(logK_m)高于类富里酸组分,且类腐殖酸组分C4的络合能力(f)最强,类腐殖酸组分的logK_m和f值总体上表现为:PSB-DOm>mSB-DOm>RSB-DOm.二维相关光谱分析发现,类富里酸组分对Cu^(2+)最敏感,而Cu^(2+)优先与类腐殖酸组分结合.研究结果有助于进一步揭示生物质炭的DOm对Cu^(2+)环境行为的影响机制.

关键词：生物质炭溶解性有机质二维相关光谱平行因子分析铜