Dynamic flood disaster simulation is an emerging and promising technology significantly useful in urban planning,risk assessment,and integrated decision support systems.It is still an important issue to integrate the ...Dynamic flood disaster simulation is an emerging and promising technology significantly useful in urban planning,risk assessment,and integrated decision support systems.It is still an important issue to integrate the large assets such as dynamic observational data,numerical flood simulation models,geographic information technologies,and computing resources into a unified framework.For the intended end user,it is also a holistic solution to create computer interpretable representations and gain insightful understanding of the dynamic disaster processes,the complex impacts,and interactions of disaster factors.In particular,it is still difficult to access and join harmonized data,processing algorithms,and models that are provided by different environmental information infrastructures.In this paper,we demonstrate a virtual geographic environments-based integrated environmental simulation framework for flood disaster management based on the notion of interlinked resources,which is capable of automated accumulating and manipulating of sensor data,creating dynamic geo-analysis and three-dimensional visualizations of ongoing geo-process,and updating the contents of simulation models representing the real environment.The prototype system is evaluated by applying it as a proof of concept to integrate in situ weather observations,numerical weather and flood disaster simulation models,visualization,and analysis of the real time flood event.Case applications indicate that the developed framework can be adopted for use by decision-makers for short-term planning and control since the resulting simulation and visualization are completely based on the latest status of environment.展开更多
Parametric study is carried out in the present article to investigate the unsteady performance of solar energy gain and heat retention of two different integrated-collector-storage systems. The systems are the convent...Parametric study is carried out in the present article to investigate the unsteady performance of solar energy gain and heat retention of two different integrated-collector-storage systems. The systems are the conventional rectangular-shaped storage tank and the modified tank shaped as rectangular cuboid with one semi -circular top. The two systems have the same absorber surface area and volume for water. The heat and fluid flow is assumed to be unsteady, two-dimensional, laminar and incompressible. The performances of the two systems are evaluated based on the maximum temperature in the system during daytime heating period and nighttime cooling period. For comprehensive study, 24 hours simulations for 3 cases with different wall boundary condition impose on the absorber plate are investigated. The simulation results show that the modified system has better heat retain than the conventional system. Periodic variations of both systems are investigated, and it is found that both systems show consistent results on different days. The modified system is able to store most of the thermal energy in the semi-circular top region with higher temperature than that of the conventional system.展开更多
For operation and manipulation with nanometric positioning precision,an integrated micro nano-positioning xy-stage is developed,which is mainly composed of a silicon-based xy-stage,comb-driven actuator and displacemen...For operation and manipulation with nanometric positioning precision,an integrated micro nano-positioning xy-stage is developed,which is mainly composed of a silicon-based xy-stage,comb-driven actuator and displacement sensor.The high-aspect-ratio comb-driven xy-stage is achieved by deep reactive ion etching (DRIE) in both sides of wafer.The displacement sensor is mainly composed of four vertical sidewall surface piezoresistor connected to form a full Wheatstone bridge.A simple vertical sidewall surface piezoresistor process which improves on the basis of the conventional surface piezoresistor technique is proposed.The experimental results verify the integrated micro nano-positioning xy-stage including the vertical sidewall surface piezoresistor technique.The sensitivity of the fabricated piezoresistive sensors is better than 1.17 mV/μm without amplification and the linearity is better than 0.814%.Under 30 V driving voltage,a ±10 μm single-axis displacement is measured without crosstalk.The displacement resolution of the micro xy-stage is better than 10.8 nm.展开更多
Single-photon sources are building blocks for photonic quantum information processes. Of the many single-photon generation schemes, electrically driven single-photon sources have the advantages of realizing monolithic...Single-photon sources are building blocks for photonic quantum information processes. Of the many single-photon generation schemes, electrically driven single-photon sources have the advantages of realizing monolithic integration of quantum light sources and detectors without optical filtering, thus greatly simplify the integrated quantum photonic circuits. Here, we review recent advances on electrically driven single-photon sources based on solid-state quantum emitters, such as semiconductor epitaxial quantum dots, colloidal quantum dots, carbon nanotubes, molecules, and defect states in diamond, SiC and layered semiconductors. In particular, the merits and drawbacks of each system are discussed. Finally, the article is concluded by discussing the challenges that remain for electrically driven single-photon sources.展开更多
This paper presents a Butterfly Optimization Algorithm(BOA)with a wind-driven mechanism for avoiding natural enemies known as WDBOA.To further balance the basic BOA algorithm's exploration and exploitation capabil...This paper presents a Butterfly Optimization Algorithm(BOA)with a wind-driven mechanism for avoiding natural enemies known as WDBOA.To further balance the basic BOA algorithm's exploration and exploitation capabilities,the butterfly actions were divided into downwind and upwind states.The algorithm of exploration ability was improved with the wind,while the algorithm of exploitation ability was improved against the wind.Also,a mechanism of avoiding natural enemies based on Lévy flight was introduced for the purpose of enhancing its global searching ability.Aiming at improving the explorative performance at the initial stages and later stages,the fragrance generation method was modified.To evaluate the effectiveness of the suggested algorithm,a comparative study was done with six classical metaheuristic algorithms and three BOA variant optimization techniques on 18 benchmark functions.Further,the performance of the suggested technique in addressing some complicated problems in various dimensions was evaluated using CEC 2017 and CEC 2020.Finally,the WDBOA algorithm is used proportional-integral-derivative(PID)controller parameter optimization.Experimental results demonstrate that the WDBOA based PID controller has better control performance in comparison with other PID controllers tuned by the Genetic Algorithm(GA),Flower Pollination Algorithm(FPA),Cuckoo Search(CS)and BOA.展开更多
This study is concerned with the numerical approximation of the extended Fisher-Kolmogorov equation with a modified boundary integral method. A key aspect of this formulation is that it relaxes the domain-driven appro...This study is concerned with the numerical approximation of the extended Fisher-Kolmogorov equation with a modified boundary integral method. A key aspect of this formulation is that it relaxes the domain-driven approach of a typical boundary element (BEM) technique. While its discretization keeps faith with the second order accurate BEM formulation, its implementation is element-based. This leads to a local solution of all integral equation and their final assembly into a slender and banded coefficient matrix which is far easier to manipulate numerically. This outcome is much better than working with BEM’s fully populated coefficient matrices resulting from a numerical encounter with the problem domain especially for nonlinear, transient, and heterogeneous problems. Faithful results of high accuracy are achieved when the results obtained herein are compared with those available in literature.展开更多
The relationships and the features of integration between Enterprise ProcessMonitoring and Controlling System(EPMCS)and Enterprise Process Related Applications(EPRA)wereanalyzed.An integration architecture centered on...The relationships and the features of integration between Enterprise ProcessMonitoring and Controlling System(EPMCS)and Enterprise Process Related Applications(EPRA)wereanalyzed.An integration architecture centered on EPMCS was presented,in which there were fourlayers to connect from EPMCS to EPRA:EPMCS,application integration layer,transport layer andEPRA,and there were four layers used to etstablish integration:presentation layer,function layer,data layer and system layer.The frameworks to connect EPMCS and EPRA were designed,thatEnterprise-Independent Model(EIM),Enterprise-Specific Model(ESM)and meta-model to describe thesetwo models were defined.The method to integrate data based on XML was designed to exchange datafrom EPMCS to EPRA according to the mapping between EIM and ESM.The approches are suitable forintegrating EPMCS and systems in Product Data Management(PDM),project management and enterprisebusiness management.展开更多
Nowadays, Model Driven Development (MDD) is a powerful technique for modelling complex systems and also for aligning business and information technology (IT), giving designers the ability to execute business models as...Nowadays, Model Driven Development (MDD) is a powerful technique for modelling complex systems and also for aligning business and information technology (IT), giving designers the ability to execute business models as they are intended to be run and behaved in the business environment. The Object Management Group (OMG) adopted many business standards into the Model Driven Architecture (MDA) environment e.g. Semantics of Business Vocabulary and Business Rules (SBVR), the Business Motivation Model (BMM), Business Process Modelling and Notation (BPMN) and Organisational Structure Model (OSM). These can work together to model different aspects of the enterprise at the business level. However, these models lack reasoning and dynamic simulation: there is no significant way to simulate discrete and continuous time system behaviour or to build arguments for reasoning about the design options within the OMG specifications. In this paper we propose an approach to overcoming this problem, by integrating a set of modelling tools into one single platform, taking advantage of meta-modelling techniques to integrate new tools with the OMG specifications in a model driven environment. The prospective framework should be able to tackle advanced analysis and design problems by intertwining design, reasoning and simulation to achieve a higher level of design maturity through implementing the desired scenario.展开更多
The time delay integration charge coupled device(TDI CCD)is the key component in remote sensing systems.The paper analyzes the structure and the working principles of the device according to a customized TDI CCD chip....The time delay integration charge coupled device(TDI CCD)is the key component in remote sensing systems.The paper analyzes the structure and the working principles of the device according to a customized TDI CCD chip.Employing the special clock resources and large-scale phase locked logic(PLL)in field-programmable gate arrays(FPGA),a timing-driven approach is proposed,using which all timing signals including reset gate,horizontal and vertical timing signals,are implemented in one chip.This not only reduces printed circuit board(PCB)space,but also enhances the portability of the system.By studying and calculating CCD parameters thoroughly,load capacity and power consumption,package,etc,are compared between various candidates chips,and detailed comparison results are also listed in table.Experimental results show that clock generator and driving circuit satisfy the requirements of high speed TDI CCD.展开更多
基金This study is supported by the National High Technology Research and Development Program of China(863 Program)(Nos.2012AA121305 and 2013AA120701)the National Natural Science Foundation of China(Nos.41471320 and 41201440).
文摘Dynamic flood disaster simulation is an emerging and promising technology significantly useful in urban planning,risk assessment,and integrated decision support systems.It is still an important issue to integrate the large assets such as dynamic observational data,numerical flood simulation models,geographic information technologies,and computing resources into a unified framework.For the intended end user,it is also a holistic solution to create computer interpretable representations and gain insightful understanding of the dynamic disaster processes,the complex impacts,and interactions of disaster factors.In particular,it is still difficult to access and join harmonized data,processing algorithms,and models that are provided by different environmental information infrastructures.In this paper,we demonstrate a virtual geographic environments-based integrated environmental simulation framework for flood disaster management based on the notion of interlinked resources,which is capable of automated accumulating and manipulating of sensor data,creating dynamic geo-analysis and three-dimensional visualizations of ongoing geo-process,and updating the contents of simulation models representing the real environment.The prototype system is evaluated by applying it as a proof of concept to integrate in situ weather observations,numerical weather and flood disaster simulation models,visualization,and analysis of the real time flood event.Case applications indicate that the developed framework can be adopted for use by decision-makers for short-term planning and control since the resulting simulation and visualization are completely based on the latest status of environment.
文摘Parametric study is carried out in the present article to investigate the unsteady performance of solar energy gain and heat retention of two different integrated-collector-storage systems. The systems are the conventional rectangular-shaped storage tank and the modified tank shaped as rectangular cuboid with one semi -circular top. The two systems have the same absorber surface area and volume for water. The heat and fluid flow is assumed to be unsteady, two-dimensional, laminar and incompressible. The performances of the two systems are evaluated based on the maximum temperature in the system during daytime heating period and nighttime cooling period. For comprehensive study, 24 hours simulations for 3 cases with different wall boundary condition impose on the absorber plate are investigated. The simulation results show that the modified system has better heat retain than the conventional system. Periodic variations of both systems are investigated, and it is found that both systems show consistent results on different days. The modified system is able to store most of the thermal energy in the semi-circular top region with higher temperature than that of the conventional system.
基金Funded by the High Technology Research and Development Programme of China (2007AA04Z315)
文摘For operation and manipulation with nanometric positioning precision,an integrated micro nano-positioning xy-stage is developed,which is mainly composed of a silicon-based xy-stage,comb-driven actuator and displacement sensor.The high-aspect-ratio comb-driven xy-stage is achieved by deep reactive ion etching (DRIE) in both sides of wafer.The displacement sensor is mainly composed of four vertical sidewall surface piezoresistor connected to form a full Wheatstone bridge.A simple vertical sidewall surface piezoresistor process which improves on the basis of the conventional surface piezoresistor technique is proposed.The experimental results verify the integrated micro nano-positioning xy-stage including the vertical sidewall surface piezoresistor technique.The sensitivity of the fabricated piezoresistive sensors is better than 1.17 mV/μm without amplification and the linearity is better than 0.814%.Under 30 V driving voltage,a ±10 μm single-axis displacement is measured without crosstalk.The displacement resolution of the micro xy-stage is better than 10.8 nm.
基金financial support from the National Key R&D Program of China(No.2016YFB0401600)the National Natural Science Foundation of China(No.61635009)the Fundamental Research Funds for the Central Universities(No.2018FZA5004)
文摘Single-photon sources are building blocks for photonic quantum information processes. Of the many single-photon generation schemes, electrically driven single-photon sources have the advantages of realizing monolithic integration of quantum light sources and detectors without optical filtering, thus greatly simplify the integrated quantum photonic circuits. Here, we review recent advances on electrically driven single-photon sources based on solid-state quantum emitters, such as semiconductor epitaxial quantum dots, colloidal quantum dots, carbon nanotubes, molecules, and defect states in diamond, SiC and layered semiconductors. In particular, the merits and drawbacks of each system are discussed. Finally, the article is concluded by discussing the challenges that remain for electrically driven single-photon sources.
基金This work was supported by National Natural Science Foundation of China under Grant U21A20464,62066005Project of the Guangxi Science and Technology under Grant No.ZL23014016.
文摘This paper presents a Butterfly Optimization Algorithm(BOA)with a wind-driven mechanism for avoiding natural enemies known as WDBOA.To further balance the basic BOA algorithm's exploration and exploitation capabilities,the butterfly actions were divided into downwind and upwind states.The algorithm of exploration ability was improved with the wind,while the algorithm of exploitation ability was improved against the wind.Also,a mechanism of avoiding natural enemies based on Lévy flight was introduced for the purpose of enhancing its global searching ability.Aiming at improving the explorative performance at the initial stages and later stages,the fragrance generation method was modified.To evaluate the effectiveness of the suggested algorithm,a comparative study was done with six classical metaheuristic algorithms and three BOA variant optimization techniques on 18 benchmark functions.Further,the performance of the suggested technique in addressing some complicated problems in various dimensions was evaluated using CEC 2017 and CEC 2020.Finally,the WDBOA algorithm is used proportional-integral-derivative(PID)controller parameter optimization.Experimental results demonstrate that the WDBOA based PID controller has better control performance in comparison with other PID controllers tuned by the Genetic Algorithm(GA),Flower Pollination Algorithm(FPA),Cuckoo Search(CS)and BOA.
文摘This study is concerned with the numerical approximation of the extended Fisher-Kolmogorov equation with a modified boundary integral method. A key aspect of this formulation is that it relaxes the domain-driven approach of a typical boundary element (BEM) technique. While its discretization keeps faith with the second order accurate BEM formulation, its implementation is element-based. This leads to a local solution of all integral equation and their final assembly into a slender and banded coefficient matrix which is far easier to manipulate numerically. This outcome is much better than working with BEM’s fully populated coefficient matrices resulting from a numerical encounter with the problem domain especially for nonlinear, transient, and heterogeneous problems. Faithful results of high accuracy are achieved when the results obtained herein are compared with those available in literature.
基金the National Aviation Science Foundation of China(02E51007,03F51063)
文摘The relationships and the features of integration between Enterprise ProcessMonitoring and Controlling System(EPMCS)and Enterprise Process Related Applications(EPRA)wereanalyzed.An integration architecture centered on EPMCS was presented,in which there were fourlayers to connect from EPMCS to EPRA:EPMCS,application integration layer,transport layer andEPRA,and there were four layers used to etstablish integration:presentation layer,function layer,data layer and system layer.The frameworks to connect EPMCS and EPRA were designed,thatEnterprise-Independent Model(EIM),Enterprise-Specific Model(ESM)and meta-model to describe thesetwo models were defined.The method to integrate data based on XML was designed to exchange datafrom EPMCS to EPRA according to the mapping between EIM and ESM.The approches are suitable forintegrating EPMCS and systems in Product Data Management(PDM),project management and enterprisebusiness management.
文摘Nowadays, Model Driven Development (MDD) is a powerful technique for modelling complex systems and also for aligning business and information technology (IT), giving designers the ability to execute business models as they are intended to be run and behaved in the business environment. The Object Management Group (OMG) adopted many business standards into the Model Driven Architecture (MDA) environment e.g. Semantics of Business Vocabulary and Business Rules (SBVR), the Business Motivation Model (BMM), Business Process Modelling and Notation (BPMN) and Organisational Structure Model (OSM). These can work together to model different aspects of the enterprise at the business level. However, these models lack reasoning and dynamic simulation: there is no significant way to simulate discrete and continuous time system behaviour or to build arguments for reasoning about the design options within the OMG specifications. In this paper we propose an approach to overcoming this problem, by integrating a set of modelling tools into one single platform, taking advantage of meta-modelling techniques to integrate new tools with the OMG specifications in a model driven environment. The prospective framework should be able to tackle advanced analysis and design problems by intertwining design, reasoning and simulation to achieve a higher level of design maturity through implementing the desired scenario.
基金National High Technology Research and Development Program of China(863 Program)(No.2009AA7010102)
文摘The time delay integration charge coupled device(TDI CCD)is the key component in remote sensing systems.The paper analyzes the structure and the working principles of the device according to a customized TDI CCD chip.Employing the special clock resources and large-scale phase locked logic(PLL)in field-programmable gate arrays(FPGA),a timing-driven approach is proposed,using which all timing signals including reset gate,horizontal and vertical timing signals,are implemented in one chip.This not only reduces printed circuit board(PCB)space,but also enhances the portability of the system.By studying and calculating CCD parameters thoroughly,load capacity and power consumption,package,etc,are compared between various candidates chips,and detailed comparison results are also listed in table.Experimental results show that clock generator and driving circuit satisfy the requirements of high speed TDI CCD.
