In dynamic problems the electric and magnetic fields are inseparable. At the same time, a multitude of electrostatic and magnetostatic effects permit mutually independent description. This separation appears to be pos...In dynamic problems the electric and magnetic fields are inseparable. At the same time, a multitude of electrostatic and magnetostatic effects permit mutually independent description. This separation appears to be possible and thermodynamically consistent when the bulk energy density depends only on the polarization density or, alternatively, on the magnetization density. However, when the bulk energy density depends simultaneously on the both densities, then, the electrostatic and magnetostatic effects should be studied together. There appear interesting cross-effects;among those are the change of the internal electrostatic field inside a specimen under the influence of the external magnetic fields, and vice versa. Below, in the framework of thermodynamic approach the boundary value problem for magnetoelectric plate is formulated and analyzed. The exact solution is established for the isotropic pyroelectric plate.展开更多
Multi-agent technology has been used in many complex distributed and concurrent systems. A railway system is such a safety critical system and careful inves- tigation of the functional components is very important. St...Multi-agent technology has been used in many complex distributed and concurrent systems. A railway system is such a safety critical system and careful inves- tigation of the functional components is very important. Study of the various functional components in communi- cation-based train control （CBTC） system necessitates a good structural design followed by its validation and ver- ification through a formal modelling technique. The work presented here is the follow up of our multi-agent-based CBTC system for Indian railway designed using the methodology for engineering system of software agents. Behavioural analysis of the designed system involves several operating scenarios that arise during train run, and helps in understanding the reaction of the system to such situations. This validation and verification are very important as it allows the system designer to critically evaluate the desired function of the system and to correct the design errors, if any, before its actual implementation. Modelling, validation and verification of the structural design through Coloured petri net （CPN） are central to this paper. Analysis of simulation results validates the efficacy of the design.展开更多
The methodological quality of subject-specific finite element analysis papers depends on the rigor of the study design and detailed description of key elements,while assessment instruments are often confined to clinic...The methodological quality of subject-specific finite element analysis papers depends on the rigor of the study design and detailed description of key elements,while assessment instruments are often confined to clinical trials or quasi-experiments.This study aims to present an instrument for methodological quality assessment of singlesubject finite element analysis used in computational orthopaedics(MQSSFE).Based upon existing instruments and relevant review papers,a pilot version was developed consisting of 37 items with 6 domains,including study design and presentation of findings,subject recruitment,model reconstruction and configuration,boundary and loading conditions(simulation),model verification and validation,and model assumption and validity.We interviewed four experts in the field to assess the face validity and refined the instrument.The instrument was tested for interrater reliability among two assessors on nine finite element study papers.Also,the criterion validity was evaluated by comparing the similarity of the MQSSFE and the modified Down and Black instrument.The intraclass correlation coefficient was 0.965,while the MQSSFE was significantly moderately correlated with the modified Down and Black instruments(r=0.61).We believed that MQSSFE was adequately appropriate,reliable,and valid for assessing the methodological quality for finite element studies used in computational orthopaedics.The instrument could facilitate quality assessment in the systematic reviews of finite element models and checklists for fidelity.展开更多
Injecting air under hulls of marine vessels can lead to reduction of their hydrodynamic resistance.Since experimental development of air-assisted hulls usually requires a large number of tests,numerical simulations of...Injecting air under hulls of marine vessels can lead to reduction of their hydrodynamic resistance.Since experimental development of air-assisted hulls usually requires a large number of tests,numerical simulations of air-ventilated water flows can potentially accelerate the design process.In this study,computational modeling has been carried out for the previously tested simplified hull form with an air cavity formed behind a step.To achieve proper agreement with experimental results,it is established that a sufficiently fine numerical mesh needs to be generated at the cavity re-attachment to the hull and the sharpening treatment of the air-water interface must be included.It is also shown how the cavity length can be manipulated by changing inclination of the cavity-originating step.展开更多
文摘In dynamic problems the electric and magnetic fields are inseparable. At the same time, a multitude of electrostatic and magnetostatic effects permit mutually independent description. This separation appears to be possible and thermodynamically consistent when the bulk energy density depends only on the polarization density or, alternatively, on the magnetization density. However, when the bulk energy density depends simultaneously on the both densities, then, the electrostatic and magnetostatic effects should be studied together. There appear interesting cross-effects;among those are the change of the internal electrostatic field inside a specimen under the influence of the external magnetic fields, and vice versa. Below, in the framework of thermodynamic approach the boundary value problem for magnetoelectric plate is formulated and analyzed. The exact solution is established for the isotropic pyroelectric plate.
基金The work is a part of project named ＂＇Multi- Agent based Train Operation in Moving Block Setup＂ funded by Department of Information Technology （DIT）, Ministry of Commu- nications and Information Technology, Government of India, vide Grant Number 2（6）/2010-EC dated 21/03/2011.
文摘Multi-agent technology has been used in many complex distributed and concurrent systems. A railway system is such a safety critical system and careful inves- tigation of the functional components is very important. Study of the various functional components in communi- cation-based train control （CBTC） system necessitates a good structural design followed by its validation and ver- ification through a formal modelling technique. The work presented here is the follow up of our multi-agent-based CBTC system for Indian railway designed using the methodology for engineering system of software agents. Behavioural analysis of the designed system involves several operating scenarios that arise during train run, and helps in understanding the reaction of the system to such situations. This validation and verification are very important as it allows the system designer to critically evaluate the desired function of the system and to correct the design errors, if any, before its actual implementation. Modelling, validation and verification of the structural design through Coloured petri net （CPN） are central to this paper. Analysis of simulation results validates the efficacy of the design.
基金This work was supported by the Key R&D Program granted by the Ministry of Science and Technology of China(reference number:2018YFB1107000)the National Natural Science Foundation of China(reference numbers:11732015,11972315)+1 种基金the Project of Academic Leader of Health System(reference number:PWRd2019-05)the Project of Novel Interdisciplinary of Health System(reference number:PWXx2020-08)in Pudong New Area,Shanghai,China.
文摘The methodological quality of subject-specific finite element analysis papers depends on the rigor of the study design and detailed description of key elements,while assessment instruments are often confined to clinical trials or quasi-experiments.This study aims to present an instrument for methodological quality assessment of singlesubject finite element analysis used in computational orthopaedics(MQSSFE).Based upon existing instruments and relevant review papers,a pilot version was developed consisting of 37 items with 6 domains,including study design and presentation of findings,subject recruitment,model reconstruction and configuration,boundary and loading conditions(simulation),model verification and validation,and model assumption and validity.We interviewed four experts in the field to assess the face validity and refined the instrument.The instrument was tested for interrater reliability among two assessors on nine finite element study papers.Also,the criterion validity was evaluated by comparing the similarity of the MQSSFE and the modified Down and Black instrument.The intraclass correlation coefficient was 0.965,while the MQSSFE was significantly moderately correlated with the modified Down and Black instruments(r=0.61).We believed that MQSSFE was adequately appropriate,reliable,and valid for assessing the methodological quality for finite element studies used in computational orthopaedics.The instrument could facilitate quality assessment in the systematic reviews of finite element models and checklists for fidelity.
基金the U.S.National Science Foundation under Grant no.1800135.
文摘Injecting air under hulls of marine vessels can lead to reduction of their hydrodynamic resistance.Since experimental development of air-assisted hulls usually requires a large number of tests,numerical simulations of air-ventilated water flows can potentially accelerate the design process.In this study,computational modeling has been carried out for the previously tested simplified hull form with an air cavity formed behind a step.To achieve proper agreement with experimental results,it is established that a sufficiently fine numerical mesh needs to be generated at the cavity re-attachment to the hull and the sharpening treatment of the air-water interface must be included.It is also shown how the cavity length can be manipulated by changing inclination of the cavity-originating step.
