Paleocontinental reconstruction is of the nature of multidisciplinary analysis . This paper discusses the significance of some more important disciplines , including paleomagnetism , paleoclimatology and paleobiogeogr...Paleocontinental reconstruction is of the nature of multidisciplinary analysis . This paper discusses the significance of some more important disciplines , including paleomagnetism , paleoclimatology and paleobiogeography. Top attention should be paid to the synthetic analysis and geological explanation of geophysical data . Reassembling of the paleocontinents by geometric similarities is preliminary, geological considerations should receive more attention . Several rules constraining the reconstruction are proposed and Eider poles used to reassemble some separated Precambrian median massifs to their mother continents are given . A computer software for paleocontinental reconstruction , GUDALU , is introduced . The software is flexible in that it gives the user maximum freedom to demonstrate his or her geological opinions by providing means of organizing geographic data and rotational parameters ,many kinds of map projection of different features and dynamic editing of the reconstruction maps . Finally, an example of Mesoproterozoic reconstruction is demonstrated .展开更多
As a prominent branch of computer science,computer software focuses on technology development and practical application,and it is of great importance in modern social and economic life.Universities need to train postg...As a prominent branch of computer science,computer software focuses on technology development and practical application,and it is of great importance in modern social and economic life.Universities need to train postgraduate students that master software engineering to satisfy the needs of high-level talents,preparing for the rapid development of the software industry.Postgraduate is an important stage to cultivate talented students in software engineering.Mentors in relevant majors need to combine advantages of their team while establishing an innovative mode for training talents,mining most potentials of students,and cultivating their ability.We have explored the team-based training mode of computer software major and scientific evaluation methods of innovation ability,shared critical importance in fulfilling fruitions of research,and proposed solutions to real problems especially under the background of“Double First-Class”.This paper decomposes and quantifies the evaluation indicators of the innovation ability of computer software graduate students through literature research and questionnaire surveys.Consequently,we establish a talent evaluation indexing system and build a team-based evaluation system for the innovation ability of graduate student in computer software major.展开更多
Informationization plays an important role in modern life and production.And various software is one of the bases for it.Before it goes into service,software needs to go through many steps,including software developme...Informationization plays an important role in modern life and production.And various software is one of the bases for it.Before it goes into service,software needs to go through many steps,including software development,design,etc.In software development,test is the key to identify and control bugs and errors in the software.Therefore,software companies often test the software to ensure that it is qualified.In recent years,more attention has been paid to a multi-platform computer software testing method,which can make up for defects in traditional testing methods to improve test accuracy.Firstly,this paper illustrates the connotation and features of software testing.Secondly,common software testing platforms and their requirements are analyzed.Finally,this paper proposes software testing method based on multiple platforms.展开更多
Thermo' computer program is described. It is intended for computation of thermal cycle parameters during surface pulse heating. For example, during laser processing, surface heating owing to grinding, etc. It gi...Thermo' computer program is described. It is intended for computation of thermal cycle parameters during surface pulse heating. For example, during laser processing, surface heating owing to grinding, etc. It gives rates of heating, cooling, as well as temperature gradients and cumulative exposure time as function of the CURRENT TEMPERATURE, with the peak temperature at the surface as variable parameter. The indicated parameters are calculated at a surface, close to a surface (at 0.01μm)and for the points at a depth of the body. Demo ver. of the software: http://www. sstu.samara.ru/physics/fedosov/thermo_d. zip展开更多
The CORBA technique is an integration of the object-oriented conception and distributed computing technique. It can make the application within distributed heterogeneous environments reusable, portable and interoperab...The CORBA technique is an integration of the object-oriented conception and distributed computing technique. It can make the application within distributed heterogeneous environments reusable, portable and interoperable. The architecture of CORBA-based discrete event simulation systems is presented and the interface of distributed simulation objects (DSO) is defined in this paper after the DSO is identified and the synchronization mechanism among DSO is discussed.展开更多
To improve the transmission accuracy and stiffness of the ball cycloid reducer, the authors developed a novel cycloid ball reducer, which uses a full complement ball as its gear teeth. Ceramic balls are used to get be...To improve the transmission accuracy and stiffness of the ball cycloid reducer, the authors developed a novel cycloid ball reducer, which uses a full complement ball as its gear teeth. Ceramic balls are used to get better performance in severe working conditions. A simple synthesis method was also found to determine the raceway forms and compute the contact forces among the balls and raceways. The Contact Stress Analysis (CSA) computer program was used to optimize the design of the reducer. In this paper, the following topics are covered: (1) Study of the geometry of the raceways. (2) Analyses of the principal curvature of the raceways are also accomplished. In addition, the modification of the raceway is put forward. (3) The contact forces and the reducer efficiency are evaluated. (4) Study of the performance of ceramic balls used in the CBR. A reducer using the above design technique was tested and the performances show that the reducer has high precision and rigidity. An increase of more than 50 percent transmission power was realized in the new gearing.展开更多
Improved traditional ant colony algorithms,a data routing model used to the data remote exchange on WAN was presented.In the model,random heuristic factors were introduced to realize multi-path search.The updating mod...Improved traditional ant colony algorithms,a data routing model used to the data remote exchange on WAN was presented.In the model,random heuristic factors were introduced to realize multi-path search.The updating model of pheromone could adjust the pheromone concentration on the optimal path according to path load dynamically to make the system keep load balance.The simulation results show that the improved model has a higher performance on convergence and load balance.展开更多
In this paper, the composition of the hardware-in-the-loop simulation system of missile guidance system and the characteristic and function of every equipment in this simulation system are discussed. Then the principl...In this paper, the composition of the hardware-in-the-loop simulation system of missile guidance system and the characteristic and function of every equipment in this simulation system are discussed. Then the principle of this system is discussed in terms of theory, and the resemblance of prototype system with simulation system is analyzed. Also, many key problems such as equipment interface, equipment installation, modelling and software design are dealt with. At the end, the error source of simulation system is analyzed, and a strong base is built for the study of simulation system precision.展开更多
Fuzzy technology is a newly developed discipline based on fuzzy mathematics. In the recent years, it has been successfully applied into many areas, such as process control, diagnosis, evaluation, decision making and s...Fuzzy technology is a newly developed discipline based on fuzzy mathematics. In the recent years, it has been successfully applied into many areas, such as process control, diagnosis, evaluation, decision making and scheduling, especially in simulation where accurate mathematical models can not or very hard be established. In this paper, to meet the demands of fuzzy simulation, two fuzzy nets will first be presented, which are quite suitable for modeling the parallel or concurrent systems with fuzzy behavior. Then, a concept of active simulation will be introduced, in which the simulation model not only can show its fuzzy behavior, but also has a certain ability which can actively perform many very useful actions, such as automatic warning, realtime monitoring, simulation result checking, simulation model self-adapting, error recovery, simulating path tracing, system states inspecting and exception handling, by a unified approach while some specified events occur. The simulation model described by this powerful simulation modeling tool is concurrently driven by a network interpreter and an event monitor that all can be implemented by software or hardware. Besides, some interesting applications are given in the paper.展开更多
We present a method for using type theory to solve decision making problem. Our method is based on the view that decision making is a special kind of theorem proving activity. An isomorphism between problems and types...We present a method for using type theory to solve decision making problem. Our method is based on the view that decision making is a special kind of theorem proving activity. An isomorphism between problems and types, and solutions and programs has been established to support this view which is much similar to the Curry-Howard isomorphism between propositions and types, and proofs and programs. To support our method, a proof development system called PowerEpsilon has been developed, and the synthesis of a decision procedure for validity of first-order propositional logic is discussed to show the power of the system.展开更多
A suitable model is developed through the revision of the maximum entropy method (MEM) for the orientation distribution function (ODF) determination from one complete pole figure in the case of cubic materials. Its re...A suitable model is developed through the revision of the maximum entropy method (MEM) for the orientation distribution function (ODF) determination from one complete pole figure in the case of cubic materials. Its relevant software is demonstrated by a group of coefficients of the ODF and an experimental test of an Al-Li alloy. The results confirm that the model proposed in this study is accurate and reliable展开更多
Aspects of techniques for understanding and developing a system which is useful in the context of Disaster Management are outlined in the paper. The emphasis is on techniques for the development of requirements and so...Aspects of techniques for understanding and developing a system which is useful in the context of Disaster Management are outlined in the paper. The emphasis is on techniques for the development of requirements and software - specifically here for the basic, underlying computing system whose application packages (amongst others: Decision Support Sub-Systems) shall support Disaster Prediction, Relief (Damage Assessment & Mitigation) and Recovery. Throughout the body of the paper we shall be making frequent references to Decision Support Sub-Systems. As acronym for the subject domain the author has chosen: DiMaCS: Disaster Management Computing Systems.展开更多
In the design process of globoidal CAM mechanism,there are some shortcomings such as long structure design cycle,low efficiency,and no modification flexibility of parameters of similar parts.NX Open classic applicatio...In the design process of globoidal CAM mechanism,there are some shortcomings such as long structure design cycle,low efficiency,and no modification flexibility of parameters of similar parts.NX Open classic application programming interfaces(APIS)can be connected with Microsoft Visual Studio(VS).Based on NX Open application,users can develop menus,toolbars,dialog boxes and other tools to realize interactive design.Users can also call input parameters through the dialog box callback function,then activate the corresponding control application(callback function)by C++programming language and NX Open API complete code.Based on the secondary development function of UG software and VS,a digital design system suitable for high efficiency modeling of globoidal indexing CAM mechanism was developed to complete the human-machine interface interaction design.The results show that comparing the digital design system with the traditional design,the system after parametric design can not only greatly shorten the design time,but also reduce the tedious repetitive work,which proves the superiority and feasibility of the digital design.展开更多
The robustness of the software-synchronized all-optical sampling for optical performance monitoring is estimated for 10-Gb/s fiber communication systems. It reveals that the software-synchronized algorithm is sensitiv...The robustness of the software-synchronized all-optical sampling for optical performance monitoring is estimated for 10-Gb/s fiber communication systems. It reveals that the software-synchronized algorithm is sensitive to the signal degradation caused by chromatic dispersion and nonlinearity in optical fibers. The influence of timing jitter and amplitude fluctuation of the sampling pulses is also investigated. It is found that stringent requirements are imposed on the quality of the sampling pulse and the tolerance of 1-dB Q penalty is measured. Considering the practically available optical sampling pulse sources, the results indicate that the amplitude fluctuation of the sampling pulses has the dominant impacts on the software-synchronized method.展开更多
A program called TAUS, a Tool for Analyzing and Understanding Software, was developed. It is de- signed to help the programmer analyze and understand the software interactively. Its aim is to reduce the depen- dence o...A program called TAUS, a Tool for Analyzing and Understanding Software, was developed. It is de- signed to help the programmer analyze and understand the software interactively. Its aim is to reduce the depen- dence on human intelligence in software understanding and improve the programmer's understanding productivity. The design and implementation of TAUS and its application are described.展开更多
The effect of quantum well number on the quantum efficiency and temperature characteristics of In- GaN/GaN laser diodes (LDs) is determined and investigated. The 3-nm-thick In0.13Ca0.87N wells and two 6-am-thick GaN...The effect of quantum well number on the quantum efficiency and temperature characteristics of In- GaN/GaN laser diodes (LDs) is determined and investigated. The 3-nm-thick In0.13Ca0.87N wells and two 6-am-thick GaN barriers are selected as an active region for Fabry-Perot (FP) cavity waveguide edge emitting LD. The internal quantum efficiency and internal optical loss coefficient are extracted through the simulation software for single, double, and triple InGaN/GaN quantum wells. The effects of device temperature on the laser threshold current, external differential quantum efficiency (DQE), and output wavelength are also investigated. The external quantum efficiency and characteristic temperature are improved significantly when the quantum well number is two. It is indicated that the laser structures with many quantum wells will suffer from the inhomogeneity of the carrier density within the quantum well itself which affects the LD performance.展开更多
Secure XML query answering to protect data privacy and semantic cache to speed up XML query answering are two hot spots in current research areas of XML database systems. While both issues are explored respectively in...Secure XML query answering to protect data privacy and semantic cache to speed up XML query answering are two hot spots in current research areas of XML database systems. While both issues are explored respectively in depth, they have not been studied together, that is, the problem of semantic cache for secure XML query answering has not been addressed yet. In this paper, we present an interesting joint of these two aspects and propose an efficient framework of semantic cache for secure XML query answering, which can improve the performance of XML database systems under secure circumstances. Our framework combines access control, user privilege management over XML data and the state-of-the-art semantic XML query cache techniques, to ensure that data are presented only to authorized users in an efficient way. To the best of our knowledge, the approach we propose here is among the first beneficial efforts in a novel perspective of combining caching and security for XML database to improve system performance. The efficiency of our framework is verified by comprehensive experiments.展开更多
The Ronchi grating is applied to measure the large-aperture aspheric surfaces in a quantitative way on the basis of self-made software which includes Ronchi null grating design, collection of Ronchi graph, and data pr...The Ronchi grating is applied to measure the large-aperture aspheric surfaces in a quantitative way on the basis of self-made software which includes Ronchi null grating design, collection of Ronchi graph, and data processing. The measured concave parabolic mirror has a diameter of 630 mm and an F number of 1.34. The measurement result is approximately the same as that of the ZYGO interferometer. This analysis software and test method establish a good foundation for the quantitative measurement of the big error about the large-aperture aspheric surfaces of the next generation telescope.展开更多
A modified asymmetrical Czerny-Turner arrangement with a fixed plane grating is proposed to correct aberrations over a broadband spectral range by analyzing the dependence of aberrations for different wavelengths. The...A modified asymmetrical Czerny-Turner arrangement with a fixed plane grating is proposed to correct aberrations over a broadband spectral range by analyzing the dependence of aberrations for different wavelengths. The principle of design is deduced in detail. We compare the performance of this modified Czerny-Turner imaging spectrometer with that of the existing Czerny-Turner arrangement by using a practical Czerny-Turner imaging spectrometer example. The excellent performance of the modified imaging spectrometer is confirmed by simulation with ZEMAX software.展开更多
基金study is supported by the National Nature Science Foundation of China No 49070139
文摘Paleocontinental reconstruction is of the nature of multidisciplinary analysis . This paper discusses the significance of some more important disciplines , including paleomagnetism , paleoclimatology and paleobiogeography. Top attention should be paid to the synthetic analysis and geological explanation of geophysical data . Reassembling of the paleocontinents by geometric similarities is preliminary, geological considerations should receive more attention . Several rules constraining the reconstruction are proposed and Eider poles used to reassemble some separated Precambrian median massifs to their mother continents are given . A computer software for paleocontinental reconstruction , GUDALU , is introduced . The software is flexible in that it gives the user maximum freedom to demonstrate his or her geological opinions by providing means of organizing geographic data and rotational parameters ,many kinds of map projection of different features and dynamic editing of the reconstruction maps . Finally, an example of Mesoproterozoic reconstruction is demonstrated .
基金supported in part by the Postgraduate Education Reform Research Project of Beijing University of Posts and Telecommunications(2021Y022).
文摘As a prominent branch of computer science,computer software focuses on technology development and practical application,and it is of great importance in modern social and economic life.Universities need to train postgraduate students that master software engineering to satisfy the needs of high-level talents,preparing for the rapid development of the software industry.Postgraduate is an important stage to cultivate talented students in software engineering.Mentors in relevant majors need to combine advantages of their team while establishing an innovative mode for training talents,mining most potentials of students,and cultivating their ability.We have explored the team-based training mode of computer software major and scientific evaluation methods of innovation ability,shared critical importance in fulfilling fruitions of research,and proposed solutions to real problems especially under the background of“Double First-Class”.This paper decomposes and quantifies the evaluation indicators of the innovation ability of computer software graduate students through literature research and questionnaire surveys.Consequently,we establish a talent evaluation indexing system and build a team-based evaluation system for the innovation ability of graduate student in computer software major.
文摘Informationization plays an important role in modern life and production.And various software is one of the bases for it.Before it goes into service,software needs to go through many steps,including software development,design,etc.In software development,test is the key to identify and control bugs and errors in the software.Therefore,software companies often test the software to ensure that it is qualified.In recent years,more attention has been paid to a multi-platform computer software testing method,which can make up for defects in traditional testing methods to improve test accuracy.Firstly,this paper illustrates the connotation and features of software testing.Secondly,common software testing platforms and their requirements are analyzed.Finally,this paper proposes software testing method based on multiple platforms.
文摘Thermo' computer program is described. It is intended for computation of thermal cycle parameters during surface pulse heating. For example, during laser processing, surface heating owing to grinding, etc. It gives rates of heating, cooling, as well as temperature gradients and cumulative exposure time as function of the CURRENT TEMPERATURE, with the peak temperature at the surface as variable parameter. The indicated parameters are calculated at a surface, close to a surface (at 0.01μm)and for the points at a depth of the body. Demo ver. of the software: http://www. sstu.samara.ru/physics/fedosov/thermo_d. zip
基金This project was supported by "Ninth Five" National Defense Sustentation Foundation.
文摘The CORBA technique is an integration of the object-oriented conception and distributed computing technique. It can make the application within distributed heterogeneous environments reusable, portable and interoperable. The architecture of CORBA-based discrete event simulation systems is presented and the interface of distributed simulation objects (DSO) is defined in this paper after the DSO is identified and the synchronization mechanism among DSO is discussed.
文摘To improve the transmission accuracy and stiffness of the ball cycloid reducer, the authors developed a novel cycloid ball reducer, which uses a full complement ball as its gear teeth. Ceramic balls are used to get better performance in severe working conditions. A simple synthesis method was also found to determine the raceway forms and compute the contact forces among the balls and raceways. The Contact Stress Analysis (CSA) computer program was used to optimize the design of the reducer. In this paper, the following topics are covered: (1) Study of the geometry of the raceways. (2) Analyses of the principal curvature of the raceways are also accomplished. In addition, the modification of the raceway is put forward. (3) The contact forces and the reducer efficiency are evaluated. (4) Study of the performance of ceramic balls used in the CBR. A reducer using the above design technique was tested and the performances show that the reducer has high precision and rigidity. An increase of more than 50 percent transmission power was realized in the new gearing.
基金Sponsored by the National High Technology Research and Development Program of China(2006AA701306)the National Innovation Foundation of Enterprises(05C26212200378)
文摘Improved traditional ant colony algorithms,a data routing model used to the data remote exchange on WAN was presented.In the model,random heuristic factors were introduced to realize multi-path search.The updating model of pheromone could adjust the pheromone concentration on the optimal path according to path load dynamically to make the system keep load balance.The simulation results show that the improved model has a higher performance on convergence and load balance.
文摘In this paper, the composition of the hardware-in-the-loop simulation system of missile guidance system and the characteristic and function of every equipment in this simulation system are discussed. Then the principle of this system is discussed in terms of theory, and the resemblance of prototype system with simulation system is analyzed. Also, many key problems such as equipment interface, equipment installation, modelling and software design are dealt with. At the end, the error source of simulation system is analyzed, and a strong base is built for the study of simulation system precision.
文摘Fuzzy technology is a newly developed discipline based on fuzzy mathematics. In the recent years, it has been successfully applied into many areas, such as process control, diagnosis, evaluation, decision making and scheduling, especially in simulation where accurate mathematical models can not or very hard be established. In this paper, to meet the demands of fuzzy simulation, two fuzzy nets will first be presented, which are quite suitable for modeling the parallel or concurrent systems with fuzzy behavior. Then, a concept of active simulation will be introduced, in which the simulation model not only can show its fuzzy behavior, but also has a certain ability which can actively perform many very useful actions, such as automatic warning, realtime monitoring, simulation result checking, simulation model self-adapting, error recovery, simulating path tracing, system states inspecting and exception handling, by a unified approach while some specified events occur. The simulation model described by this powerful simulation modeling tool is concurrently driven by a network interpreter and an event monitor that all can be implemented by software or hardware. Besides, some interesting applications are given in the paper.
文摘We present a method for using type theory to solve decision making problem. Our method is based on the view that decision making is a special kind of theorem proving activity. An isomorphism between problems and types, and solutions and programs has been established to support this view which is much similar to the Curry-Howard isomorphism between propositions and types, and proofs and programs. To support our method, a proof development system called PowerEpsilon has been developed, and the synthesis of a decision procedure for validity of first-order propositional logic is discussed to show the power of the system.
文摘A suitable model is developed through the revision of the maximum entropy method (MEM) for the orientation distribution function (ODF) determination from one complete pole figure in the case of cubic materials. Its relevant software is demonstrated by a group of coefficients of the ODF and an experimental test of an Al-Li alloy. The results confirm that the model proposed in this study is accurate and reliable
文摘Aspects of techniques for understanding and developing a system which is useful in the context of Disaster Management are outlined in the paper. The emphasis is on techniques for the development of requirements and software - specifically here for the basic, underlying computing system whose application packages (amongst others: Decision Support Sub-Systems) shall support Disaster Prediction, Relief (Damage Assessment & Mitigation) and Recovery. Throughout the body of the paper we shall be making frequent references to Decision Support Sub-Systems. As acronym for the subject domain the author has chosen: DiMaCS: Disaster Management Computing Systems.
基金National Natural Science Foundation of China(51275210,51975251)Provi-ncial Industry-University-Research Joint Venture Project(1078081606192480)+1 种基金Jiangsu Key Laboratory of Advanced Food Manufacturing Equipment Technology(FMZ2018Y2)Six Talent Peaks(1076010241131350)。
文摘In the design process of globoidal CAM mechanism,there are some shortcomings such as long structure design cycle,low efficiency,and no modification flexibility of parameters of similar parts.NX Open classic application programming interfaces(APIS)can be connected with Microsoft Visual Studio(VS).Based on NX Open application,users can develop menus,toolbars,dialog boxes and other tools to realize interactive design.Users can also call input parameters through the dialog box callback function,then activate the corresponding control application(callback function)by C++programming language and NX Open API complete code.Based on the secondary development function of UG software and VS,a digital design system suitable for high efficiency modeling of globoidal indexing CAM mechanism was developed to complete the human-machine interface interaction design.The results show that comparing the digital design system with the traditional design,the system after parametric design can not only greatly shorten the design time,but also reduce the tedious repetitive work,which proves the superiority and feasibility of the digital design.
基金supported by the National Natural Sci-ence Foundation of China (No. 60777024)the Open Fund of Key Laboratory of Optical Communication and Lightwave Technologies,Beijing University of Posts and Telecommunications, Ministry of Education, China
文摘The robustness of the software-synchronized all-optical sampling for optical performance monitoring is estimated for 10-Gb/s fiber communication systems. It reveals that the software-synchronized algorithm is sensitive to the signal degradation caused by chromatic dispersion and nonlinearity in optical fibers. The influence of timing jitter and amplitude fluctuation of the sampling pulses is also investigated. It is found that stringent requirements are imposed on the quality of the sampling pulse and the tolerance of 1-dB Q penalty is measured. Considering the practically available optical sampling pulse sources, the results indicate that the amplitude fluctuation of the sampling pulses has the dominant impacts on the software-synchronized method.
文摘A program called TAUS, a Tool for Analyzing and Understanding Software, was developed. It is de- signed to help the programmer analyze and understand the software interactively. Its aim is to reduce the depen- dence on human intelligence in software understanding and improve the programmer's understanding productivity. The design and implementation of TAUS and its application are described.
基金supports from Universiti Sains Malaysia,Ministry of Science Technology and Innovation (MOSTI),Ministry of Higher Education are gratefully acknowl-edged
文摘The effect of quantum well number on the quantum efficiency and temperature characteristics of In- GaN/GaN laser diodes (LDs) is determined and investigated. The 3-nm-thick In0.13Ca0.87N wells and two 6-am-thick GaN barriers are selected as an active region for Fabry-Perot (FP) cavity waveguide edge emitting LD. The internal quantum efficiency and internal optical loss coefficient are extracted through the simulation software for single, double, and triple InGaN/GaN quantum wells. The effects of device temperature on the laser threshold current, external differential quantum efficiency (DQE), and output wavelength are also investigated. The external quantum efficiency and characteristic temperature are improved significantly when the quantum well number is two. It is indicated that the laser structures with many quantum wells will suffer from the inhomogeneity of the carrier density within the quantum well itself which affects the LD performance.
基金partly supported by the National Natural Science Foundation of China under Grant No. 60573094the National High Technology Research and Development 863 Program of China under Grant No. 2007AA01Z152the National Basic Research 973 Program of China under Grant No. 2006CB303103.
文摘Secure XML query answering to protect data privacy and semantic cache to speed up XML query answering are two hot spots in current research areas of XML database systems. While both issues are explored respectively in depth, they have not been studied together, that is, the problem of semantic cache for secure XML query answering has not been addressed yet. In this paper, we present an interesting joint of these two aspects and propose an efficient framework of semantic cache for secure XML query answering, which can improve the performance of XML database systems under secure circumstances. Our framework combines access control, user privilege management over XML data and the state-of-the-art semantic XML query cache techniques, to ensure that data are presented only to authorized users in an efficient way. To the best of our knowledge, the approach we propose here is among the first beneficial efforts in a novel perspective of combining caching and security for XML database to improve system performance. The efficiency of our framework is verified by comprehensive experiments.
文摘The Ronchi grating is applied to measure the large-aperture aspheric surfaces in a quantitative way on the basis of self-made software which includes Ronchi null grating design, collection of Ronchi graph, and data processing. The measured concave parabolic mirror has a diameter of 630 mm and an F number of 1.34. The measurement result is approximately the same as that of the ZYGO interferometer. This analysis software and test method establish a good foundation for the quantitative measurement of the big error about the large-aperture aspheric surfaces of the next generation telescope.
基金supported by the National Natural Science Foundation of China under Grant No.40675083.
文摘A modified asymmetrical Czerny-Turner arrangement with a fixed plane grating is proposed to correct aberrations over a broadband spectral range by analyzing the dependence of aberrations for different wavelengths. The principle of design is deduced in detail. We compare the performance of this modified Czerny-Turner imaging spectrometer with that of the existing Czerny-Turner arrangement by using a practical Czerny-Turner imaging spectrometer example. The excellent performance of the modified imaging spectrometer is confirmed by simulation with ZEMAX software.