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Extended context-based semantic communication system for text transmission
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作者 Yueling Liu Shengteng Jiang +5 位作者 Yichi Zhang Kuo Cao Li Zhou Boon-Chong Seet Haitao Zhao Jibo Wei 《Digital Communications and Networks》 SCIE CSCD 2024年第3期568-576,共9页
Context information is significant for semantic extraction and recovery of messages in semantic communication.However,context information is not fully utilized in the existing semantic communication systems since re-l... Context information is significant for semantic extraction and recovery of messages in semantic communication.However,context information is not fully utilized in the existing semantic communication systems since re-lationships between sentences are often ignored.In this paper,we propose an Extended Context-based Semantic Communication(ECSC)system for text transmission,in which context information within and between sentences is explored for semantic representation and recovery.At the encoder,self-attention and segment-level relative attention are used to extract context information within and between sentences,respectively.In addition,a gate mechanism is adopted at the encoder to incorporate the context information from different ranges.At the decoder,Transformer-XL is introduced to obtain more semantic information from the historical communication processes for semantic recovery.Simulation results show the effectiveness of our proposed model in improving the semantic accuracy between transmitted and recovered messages under various channel conditions. 展开更多
关键词 semantic communication extended context Transformer-XL
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Extended Deep Learning Algorithm for Improved Brain Tumor Diagnosis System
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作者 M.Adimoolam K.Maithili +7 位作者 N.M.Balamurugan R.Rajkumar S.Leelavathy Raju Kannadasan Mohd Anul Haq Ilyas Khan ElSayed M.Tag El Din Arfat Ahmad Khan 《Intelligent Automation & Soft Computing》 2024年第1期33-55,共23页
At present,the prediction of brain tumors is performed using Machine Learning(ML)and Deep Learning(DL)algorithms.Although various ML and DL algorithms are adapted to predict brain tumors to some range,some concerns st... At present,the prediction of brain tumors is performed using Machine Learning(ML)and Deep Learning(DL)algorithms.Although various ML and DL algorithms are adapted to predict brain tumors to some range,some concerns still need enhancement,particularly accuracy,sensitivity,false positive and false negative,to improve the brain tumor prediction system symmetrically.Therefore,this work proposed an Extended Deep Learning Algorithm(EDLA)to measure performance parameters such as accuracy,sensitivity,and false positive and false negative rates.In addition,these iterated measures were analyzed by comparing the EDLA method with the Convolutional Neural Network(CNN)way further using the SPSS tool,and respective graphical illustrations were shown.The results were that the mean performance measures for the proposed EDLA algorithm were calculated,and those measured were accuracy(97.665%),sensitivity(97.939%),false positive(3.012%),and false negative(3.182%)for ten iterations.Whereas in the case of the CNN,the algorithm means accuracy gained was 94.287%,mean sensitivity 95.612%,mean false positive 5.328%,and mean false negative 4.756%.These results show that the proposed EDLA method has outperformed existing algorithms,including CNN,and ensures symmetrically improved parameters.Thus EDLA algorithm introduces novelty concerning its performance and particular activation function.This proposed method will be utilized effectively in brain tumor detection in a precise and accurate manner.This algorithm would apply to brain tumor diagnosis and be involved in various medical diagnoses aftermodification.If the quantity of dataset records is enormous,then themethod’s computation power has to be updated. 展开更多
关键词 Brain tumor extended deep learning algorithm convolution neural network tumor detection deep learning
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Design of Medical Rehabilitation Experience System Based on Extended Reality
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作者 Zhengjie Xu Qi Zhang +3 位作者 Kaidi Xue Hongjia Yang Luyao Wang Haolong Yang 《计算机科学与技术汇刊(中英文版)》 2024年第1期6-7,共2页
This project integrates Extended Reality technology with medical rehabilitation,integrating cloud rendering.interactive experience systems,adaptation platforms,and digital scene resources.It is a innovative applicatio... This project integrates Extended Reality technology with medical rehabilitation,integrating cloud rendering.interactive experience systems,adaptation platforms,and digital scene resources.It is a innovative application research in the era of metaverset medical rehabilitation.The project uses the Maya engine for the creation of digital assets,with Unity as the main functional development platform and PICO4 as the core device,to achieve interactive and fun experience effects for various rehabilitation training devices.It solves the problems of patients being dull,low participation,lack of confidence in traditional rehabilitation training.as well as the inability of medical staff to monitor patient progress in real time and adjust rehabilitation plans better. 展开更多
关键词 Relabilitation extended Reality INTERACTION UNITY
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New Family of Exact Solutions and Chaotic Soltions of Generalized Breor-Kaup System in (2+1)-Dimensions via an Extended Mapping Approach 被引量:11
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作者 FANG Jian-Ping ZHENG Chun-Long +2 位作者 ZHU Hai-Ping REN Qing-Bao CHEN Li-Qun 《Communications in Theoretical Physics》 SCIE CAS CSCD 2005年第2X期203-208,共6页
Starting from an extended mapping approach, a new type of variable separation solution with arbitrary functions of generalized (2+1)-dimensional Broer-Kaup system (GBK) system is derived. Then based on the derived sol... Starting from an extended mapping approach, a new type of variable separation solution with arbitrary functions of generalized (2+1)-dimensional Broer-Kaup system (GBK) system is derived. Then based on the derived solitary wave solution, we obtain some specific chaotic solitons to the (2+1)-dimensional GBK system. 展开更多
关键词 extended mapping approach GBK system exact solution chaotic soliton
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Extended antimicrobial prophylaxis after gastric cancer surgery: A systematic review and meta-analysis 被引量:6
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作者 Chun-Dong Zhang Yong-Ji Zeng +4 位作者 Zhen Li Jing Chen Hong-Wu Li Jia-Kui Zhang Dong-Qiu Dai 《World Journal of Gastroenterology》 SCIE CAS 2013年第13期2104-2109,共6页
AIM: To investigate the efficacy of extended antimicrobial prophylaxis (EAP) after gastrectomy by systematic review of literature and meta-analysis. METHODS: Electronic databases of PubMed, Embase, CINAHL, the Cochran... AIM: To investigate the efficacy of extended antimicrobial prophylaxis (EAP) after gastrectomy by systematic review of literature and meta-analysis. METHODS: Electronic databases of PubMed, Embase, CINAHL, the Cochrane Database of Systematic Reviews, the Cochrane Controlled Trials Register and the China National Knowledge Infrastructure were searched systematically from January 1980 to October 2012. Strict literature retrieval and data extraction were carried out independently by two reviewers and meta-analyses were conducted using RevMan 5.0.2 with statistics tools risk ratios (RRs) and intention-to-treat analyses to evaluate the items of total complications, surgical site infection, incision infection, organ (or space) infection, remote site infection, anastomotic leakage (or dehiscence) and mortality. Fixed model or random model was selected accordingly and forest plot was conducted to display RR. Likewise, Cochrane Risk of Bias Tool was applied to evaluate the quality of randomized controlled trials (RCTs) included in this meta-analysis. RESULTS: A total of 1095 patients with gastric cancer were enrolled in four RCTs. No statistically significant differences were detected between EAP and intraoperative antimicrobial prophylaxis (IAP) in total complications (RR of 0.86, 95%CI: 0.63-1.16, P = 0.32), surgical site infection (RR of 1.97, 95%CI: 0.86-4.48, P = 0.11), incision infection (RR of 4.92, 95%CI: 0.58-41.66, P = 0.14), organ or space infection (RR of 1.55, 95%CI: 0.61-3.89, P = 0.36), anastomotic leakage or dehiscence (RR of 3.85, 95%CI: 0.64-23.17, P = 0.14) and mortality (RR of 1.14, 95%CI: 0.10-13.12; P = 0.92). Likewise, multiple-dose antimicrobial prophylaxis showed no difference compared with single-dose antimicrobial prophylaxis in surgical site infection (RR of 1.10, 95%CI: 0.62-1.93, P = 0.75). Nevertheless, EAP showed a decreased remote site infection rate compared with IAP alone (RR of 0.54, 95%CI: 0.34-0.86, P = 0.01), which is the only significant finding. Unfortunately, EAP did not decrease the incidence of surgical site infections after gastrectomy; likewise, multipledose antimicrobial prophylaxis failed to decrease the incidence of surgical site infection compared with single-dose antimicrobial prophylaxis. CONCLUSION: We recommend that EAP should not be used routinely after gastrectomy until more high-quality RCTs are available. 展开更多
关键词 Gastric cancer GASTRECTOMY extended ANTIMICROBIAL PROPHYLAXIS INTRAOPERATIVE ANTIMICROBIAL PROPHYLAXIS META-ANALYSIS
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ARCHITECTURE OF MANUFACTURING EXECUTION SYSTEM IN THE EXTENDED ENTERPRISE 被引量:6
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作者 Song Haisheng College of Electronic and Mechanical Engineering, Hebei University of Science and Technology,Shijiazhuang 050054,China Wang Jiahai Zhang Shu Tongji University 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2002年第1期90-93,共4页
The extended enterprise is formed according to the philosophy of dispersednetworked manufacturing. Manufacturing execution system (MES) can close the information gap whichexists between device control system and produ... The extended enterprise is formed according to the philosophy of dispersednetworked manufacturing. Manufacturing execution system (MES) can close the information gap whichexists between device control system and production information management system. The functions andthe web-based architecture of the MES in the extended enterprise are introduced. Using thecooperating system models of object-oriented and distributed agents and CORBA, all objects keep touniform interface standards and are easily inserted to object request broker. The utilization ofdistributed MES in extended enterprise can adapt fast change of manufacturing environment andresource. It also can improve the independent management capability of manufacturing cell and theenterprise response capability to global economic competition. 展开更多
关键词 extended enterprise Manufacturing execution system Dispersed networkedmanufacturing AGENT
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Noether's theorem for non-conservative Hamilton system based on El-Nabulsi dynamical model extended by periodic laws 被引量:5
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作者 龙梓轩 张毅 《Chinese Physics B》 SCIE EI CAS CSCD 2014年第11期359-367,共9页
This paper focuses on the Noether symmetries and the conserved quantities for both holonomic and nonholonomic systems based on a new non-conservative dynamical model introduced by E1-Nabulsi. First, the E1-Nabulsi dyn... This paper focuses on the Noether symmetries and the conserved quantities for both holonomic and nonholonomic systems based on a new non-conservative dynamical model introduced by E1-Nabulsi. First, the E1-Nabulsi dynamical model which is based on a fractional integral extended by periodic laws is introduced, and E1-Nabulsi-Hamilton's canoni- cal equations for non-conservative Hamilton system with holonomic or nonholonomic constraints are established. Second, the definitions and criteria of E1-Nabulsi-Noether symmetrical transformations and quasi-symmetrical transformations are presented in terms of the invariance of E1-Nabulsi-Hamilton action under the infinitesimal transformations of the group. Fi- nally, Noether's theorems for the non-conservative Hamilton system under the E1-Nabulsi dynamical system are established, which reveal the relationship between the Noether symmetry and the conserved quantity of the system. 展开更多
关键词 Noether's theorem non-conservative Hamilton system E1-Nabulsi dynamical model fractionalintegral extended by periodic laws
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Extended Kalman filtering-based channel estimation for space-time coded MIMO-OFDM systems 被引量:5
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作者 梁永明 罗汉文 黄建国 《Journal of Shanghai University(English Edition)》 CAS 2007年第5期469-473,共5页
A space-time coded multiple-input multiple-output orthogonal frequency-division multiplexing (MIMO-OFDM) system is considered as a solution to the future wideband wireless communication system. This paper proposes a... A space-time coded multiple-input multiple-output orthogonal frequency-division multiplexing (MIMO-OFDM) system is considered as a solution to the future wideband wireless communication system. This paper proposes an extended Kalman filtering-based (EKF-based) channel estimation method for space-time coded MIMO-OFDM systems. The proposed method can exploit pilot symbols and an extended Kalman filter to estimate channel without any prior knowledge of channel statistics. In comparison with the least square (LS) and the least mean square (LMS) methods, the EKF-based approach has a better performance in theory. Computer simulations demonstrate the proposed method outperforms the LS and LMS methods. Therefore it can offer draznatic system performance improvement at a modest cost of computational complexity. 展开更多
关键词 multiple-input multiple-output orthogonal frequency-division multiplexing (MIMO-OFDM) channel estimation extended Kalman filtering (EKF) least mean square (LMS).
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Simulation on model predictive control for PMSM drive system based on double extended state observer 被引量:4
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作者 CUI Hong-wei TENG Qing-fang +1 位作者 ZHU Jian-guo GUO You-guang 《Journal of Measurement Science and Instrumentation》 CAS CSCD 2018年第4期380-387,共8页
A novel double extended state observer(DESO)based on model predictive torque control(MPTC)strategy is developed for three-phase permanent magnet synchronous motor(PMSM)drive system without current sensor.In general,to... A novel double extended state observer(DESO)based on model predictive torque control(MPTC)strategy is developed for three-phase permanent magnet synchronous motor(PMSM)drive system without current sensor.In general,to achieve high-precision control,two-phase current sensors are necessary for successful implementation of MPTC.For this purpose,two ESOs are used to estimate q-axis current and stator resistance respectively,and then based on this,d-axis current is estimated.Moreover,to reduce torque and flux ripple and to improve the performance of the torque and speed,MPTC strategy is designed.The simulation results validate the feasibility and effectiveness of the proposed scheme. 展开更多
关键词 double extended state observer(DESO) model predictive torque control(MPTC) permanent magnet synchronous motor(PMSM)drive system without current sensor
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Galerkin-based extended Kalman filter with application to CO2 removal system 被引量:2
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作者 LV Ming-bo LI Yun-hua GUO Rui 《Journal of Central South University》 SCIE EI CAS CSCD 2020年第6期1780-1789,共10页
The carbon dioxide removal system is the most critical system for controlling CO2 mass concentration in long-term manned spacecraft.In order to ensure the controlling CO2 mass concentration in the cabin within the all... The carbon dioxide removal system is the most critical system for controlling CO2 mass concentration in long-term manned spacecraft.In order to ensure the controlling CO2 mass concentration in the cabin within the allowable range,the state of CO2 removal system needs to be estimated in real time.In this paper,the mathematical model is firstly established that describes the actual system conditions and then the Galerkin-based extended Kalman filter algorithm is proposed for the estimation of the state of CO2.This method transforms partial differential equation to ordinary differential equation by using Galerkin approaching method,and then carries out the state estimation by using extended Kalman filter.Simulation experiments were performed with the qualification of the actual manned space mission.The simulation results show that the proposed method can effectively estimate the system state while avoiding the problem of dimensional explosion,and has strong robustness regarding measurement noise.Thus,this method can establish a basis for system fault diagnosis and fault positioning. 展开更多
关键词 carbon dioxide removal system GALERKIN infinite nonlinear filter extend Kalman filter
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Extended sine-Gordon Equation Method and Its Application to Maccari's System 被引量:2
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作者 SONG Li-Na ZHANG Hong-Qing 《Communications in Theoretical Physics》 SCIE CAS CSCD 2005年第5X期783-788,共6页
An extended sine-Gordon equation method is proposed to construct exact travelling wave solutions to Maccari's equation based upon a generalized sine-Gordon equation. It is shown that more new travelling wave solut... An extended sine-Gordon equation method is proposed to construct exact travelling wave solutions to Maccari's equation based upon a generalized sine-Gordon equation. It is shown that more new travelling wave solutions can be found by this new method, which include bell-shaped soliton solutions, kink-shaped soliton solutions, periodic wave solution, and new travelling waves. 展开更多
关键词 Maccari's system exact travelling wave solution extended sine-Gordon equation method
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Exact Traveling Wave Solutions for the System of Shallow Water Wave Equations and Modified Liouville Equation Using Extended Jacobian Elliptic Function Expansion Method 被引量:6
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作者 Emad H. M. Zahran Mostafa M. A. Khater 《American Journal of Computational Mathematics》 2014年第5期455-463,共9页
In this work, an extended Jacobian elliptic function expansion method is proposed for constructing the exact solutions of nonlinear evolution equations. The validity and reliability of the method are tested by its app... In this work, an extended Jacobian elliptic function expansion method is proposed for constructing the exact solutions of nonlinear evolution equations. The validity and reliability of the method are tested by its applications to the system of shallow water wave equations and modified Liouville equation which play an important role in mathematical physics. 展开更多
关键词 extended JACOBIAN Elliptic Function Expansion Method The system of Shallow Water WAVE Equations MODIFIED LIOUVILLE Equation Traveling WAVE SOLUTIONS SOLITARY WAVE SOLUTIONS
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New repairable system model with two types repair based on extended geometric process 被引量:1
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作者 WANG Junyuan YE Jimin XIE Pengfei 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2019年第3期613-623,共11页
A simple repairable system with one repairman is considered. As the system working age is up to a specified time T, the repairman will repair the component preventively, and it will go back to work as soon as the repa... A simple repairable system with one repairman is considered. As the system working age is up to a specified time T, the repairman will repair the component preventively, and it will go back to work as soon as the repair finished. When the system failure, the repairman repair it immediately. The time interval of the preventive repair and the failure correction is described with the extended geometric process. Different from the available replacement policy which is usually based on the failure number or the working age of the system, the bivariate policy (T,N) is considered. The explicit expression of the long-run average cost rate function C(T,N) of the system is derived. Through alternatively minimize the cost rate function C(T,N), the optimal replacement policy (T?,N?) is obtained, and it proves that the optimal policy is unique. Numerical cases illustrate the conclusion, and the sensitivity analysis of the parameters is carried out. 展开更多
关键词 extended geometric process average cost rate REPLACEMENT policy RENEWAL REWARD THEOREM
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The ‘Two oceans and one sea' extended range numerical prediction system with an ultra-high resolution atmosphere-ocean-land regional coupled model 被引量:2
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作者 Zhang Shao-Qing Yang LIU +4 位作者 Ma Xiao-Hui Wang Hong-Na Zhang Xue-Feng Yu Xiao-Lin Lu Lv 《Atmospheric and Oceanic Science Letters》 CSCD 2018年第4期364-371,共8页
The‘Two Oceans and One Sea’area(West Pacific,Indian Ocean,and South China Sea;15°S–60°N,39°–178°E)is a core strategic area for the‘21st Century Maritime Silk Road’project,as well as national ... The‘Two Oceans and One Sea’area(West Pacific,Indian Ocean,and South China Sea;15°S–60°N,39°–178°E)is a core strategic area for the‘21st Century Maritime Silk Road’project,as well as national defense.With the increasing demand for disaster prevention and mitigation,the importance of 10–30-day extended range prediction,between the conventional short-term(around seven days)and the climate scale(longer than one month),is apparent.However,marine extended range prediction is still a‘blank point’in China,making the early warning of marine disasters almost impossible.Here,the authors introduce a recently launched Chinese national project on a numerical forecasting system for extended range prediction in the‘Two Oceans and One Sea’area based on a regional ultra-high resolution multi-layer coupled model,including the scientific aims,technical scheme,innovation,and expected achievements.The completion of this prediction system is of considerable significance for the economic development and national security of China. 展开更多
关键词 Numerical prediction system ultra-high resolution multi-layer coupled model extended range prediction
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An Extended Closed-loop Subspace Identification Method for Error-in-variables Systems 被引量:1
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作者 刘涛 邵诚 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2012年第6期1136-1141,共6页
A closed-loop subspace identification method is proposed for industrial systems subject to noisy input-output observations, known as the error-in-variables (EIV) problem. Using the orthogonal projection approach to el... A closed-loop subspace identification method is proposed for industrial systems subject to noisy input-output observations, known as the error-in-variables (EIV) problem. Using the orthogonal projection approach to eliminate the noise influence, consistent estimation is guaranteed for the deterministic part of such a system. A strict proof is given for analyzing the rank condition for such orthogonal projection, in order to use the principal component analysis (PCA) based singular value decomposition (SVD) to derive the extended observability matrix and lower triangular Toeliptz matrix of the plant state-space model. In the result, the plant state matrices can be retrieved in a transparent manner from the above matrices. An illustrative example is shown to demonstrate the effectiveness and merits of the proposed subspace identification method. 展开更多
关键词 closed-loop error-in-variables system subspace identification extended observability matrix orthogonal projection
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Application of Extended Projective Riccati Equation Method to(2+1)-Dimensional Broer-Kaup-Kupershmidt System 被引量:1
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作者 LU Bin ZHANG Hong-Qing 《Communications in Theoretical Physics》 SCIE CAS CSCD 2008年第10期814-820,共7页
In this paper, extended projective Riccati equation method is presented for constructing more new exact solutions of nonlinear differential equations in mathematical physics, which is direct and more powerful than pro... In this paper, extended projective Riccati equation method is presented for constructing more new exact solutions of nonlinear differential equations in mathematical physics, which is direct and more powerful than projective Riccati equation method. In order to illustrate the effect of the method, Broer Kaup Kupershmidt system is employed and Jacobi doubly periodic solutions are obtained. This algorithm can also be applied to other nonlinear differential equations. 展开更多
关键词 nonlinear- partial differential equations extended projective Riccati equation method exact solutions Broer- Kaup Kupershmidt system
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Functionality evaluation of system of systems architecture based on extended influence diagrams 被引量:1
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作者 ZHANG Mengmeng CHEN Honghui +2 位作者 ZHANG Xiaoxue LUO Aimin LIU Junxian 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2018年第3期510-518,共9页
System of systems architecture(SoSA) has received increasing emphasis by scholars since Zachman ignited its flame in 1987. Given its complexity and abstractness, it is critical to validate and evaluate SoSA to ensur... System of systems architecture(SoSA) has received increasing emphasis by scholars since Zachman ignited its flame in 1987. Given its complexity and abstractness, it is critical to validate and evaluate SoSA to ensure requirements have been met.Multiple qualities are discussed in the literature of SoSA evaluation, while research on functionality is scarce. In order to assess SoSA functionality, an extended influence diagram(EID) is developed in this paper. Meanwhile, a simulation method is proposed to elicit the conditional probabilities in EID through designing and executing SoSA. An illustrative anti-missile architecture case is introduced for EID development, architecture design, and simulation. 展开更多
关键词 system of systems architecture(SoSA) functionality evaluation extended influence diagram(EID) anti-missile architecture SIMULATION
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Backstepping Sliding Mode Control Based on Extended State Observer for Hydraulic Servo System 被引量:1
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作者 Zhenshuai Wan Yu Fu +1 位作者 Chong Liu Longwang Yue 《Intelligent Automation & Soft Computing》 SCIE 2023年第6期3565-3581,共17页
Hydraulic servo system plays an important role in industrial fields due to the advantages of high response,small size-to-power ratio and large driving force.However,inherent nonlinear behaviors and modeling uncertaint... Hydraulic servo system plays an important role in industrial fields due to the advantages of high response,small size-to-power ratio and large driving force.However,inherent nonlinear behaviors and modeling uncertainties are the main obstacles for hydraulic servo system to achieve high tracking perfor-mance.To deal with these difficulties,this paper presents a backstepping sliding mode controller to improve the dynamic tracking performance and anti-interfer-ence ability.For this purpose,the nonlinear dynamic model is firstly established,where the nonlinear behaviors and modeling uncertainties are lumped as one term.Then,the extended state observer is introduced to estimate the lumped distur-bance.The system stability is proved by using the Lyapunov stability theorem.Finally,comparative simulation and experimental are conducted on a hydraulic servo system platform to verify the efficiency of the proposed control scheme. 展开更多
关键词 Hydraulic servo system nonlinear behaviors modeling uncertainties backstepping control sliding mode control extended state observer
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Dynamic Stability Analysis of Linear Time-varying Systems via an Extended Modal Identification Approach 被引量:2
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作者 Zhisai MA Li LIU +3 位作者 Sida ZHOU Frank NAETS Ward HEYLEN Wim DESMET 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2017年第2期459-471,共13页
The problem of linear time-varying(LTV) system modal analysis is considered based on time-dependent state space representations, as classical modal analysis of linear time-invariant systems and current LTV system mo... The problem of linear time-varying(LTV) system modal analysis is considered based on time-dependent state space representations, as classical modal analysis of linear time-invariant systems and current LTV system modal analysis under the "frozen-time" assumption are not able to determine the dynamic stability of LTV systems. Time-dependent state space representations of LTV systems are first introduced, and the corresponding modal analysis theories are subsequently presented via a stabilitypreserving state transformation. The time-varying modes of LTV systems are extended in terms of uniqueness, and are further interpreted to determine the system's stability. An extended modal identification is proposed to estimate the time-varying modes, consisting of the estimation of the state transition matrix via a subspace-based method and the extraction of the time-varying modes by the QR decomposition. The proposed approach is numerically validated by three numerical cases, and is experimentally validated by a coupled moving-mass simply supported beam exper- imental case. The proposed approach is capable of accurately estimating the time-varying modes, and provides anew way to determine the dynamic stability of LTV systems by using the estimated time-varying modes. 展开更多
关键词 Linear time·varying systems · extended modal identification · Dynamic stability analysis · Time·varying modes
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Carreau-Extended非牛顿流体圆管层流流动的摄动解
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作者 叶俊华 雷卫明 +5 位作者 王昭华 马文军 赵磊 马建荣 史高均 孙杰 《管道技术与设备》 CAS 2024年第3期1-5,25,共6页
非牛顿流体在工业生产中应用广泛。文中基于同时包含屈服应力、时间常数和幂律指数的Carreau-Extended(简称Carreau-E)复杂流变方程及剪切应力与压降平衡关系,建立了圆管内充分发展的稳定Carreau-E流体层流管流的运动方程,并采用摄动方... 非牛顿流体在工业生产中应用广泛。文中基于同时包含屈服应力、时间常数和幂律指数的Carreau-Extended(简称Carreau-E)复杂流变方程及剪切应力与压降平衡关系,建立了圆管内充分发展的稳定Carreau-E流体层流管流的运动方程,并采用摄动方法推导出相应运动方程的一阶渐近解,获得了不同类型流体管流的速度分布以及压力梯度、流核宽度、屈服应力和时间常数对Carreau-E流体管流流场分布的影响规律,该研究对Carreau-E流体及其他复杂非牛顿流体管流特性研究具有参考价值。 展开更多
关键词 Carreau-extended流体 层流管流 流场 摄动解
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