Radio frequency(RF)cavities for advanced storage rings,also known as diffraction-limited storage rings,are under development.To this end,a competitive and promising approach involves normal-conducting continuous wave ...Radio frequency(RF)cavities for advanced storage rings,also known as diffraction-limited storage rings,are under development.To this end,a competitive and promising approach involves normal-conducting continuous wave technology.The design and preliminary test of a 499.654 MHz RF cavity for the Wuhan Advanced Light Source(WALS)based on specific beam parameters were conducted at the SSRF.Multi-objective evolutionary algorithms have been utilized to optimize RF properties,such as the power loss and power density,resulting in better performance in the continuous wave mode.Further improvements were made to suppress multipacting effects in the working area.To operate stably with the beam,higher-order mode dampers were applied to better address the coupling bunch instability than in previous designs,along with thermal analysis to achieve the desired RF performance.Comprehensive simulation studies demonstrated the stable operation of the RF cavity at the defined beam parameters in the WALS design.A prototype RF cavity was then developed,and the RF performance results in a low-power test showed good agreement with the design and simulation,exhibiting readiness for high-power experiments and operation.展开更多
The early involvement of test and evaluation can significantly reduce the cost of modifying issues and errors found in the later stages of aircraft development and design process.This paper presents a methodology for ...The early involvement of test and evaluation can significantly reduce the cost of modifying issues and errors found in the later stages of aircraft development and design process.This paper presents a methodology for aircraft mission effectiveness evaluation and design space exploration based on Virtual Operational Test(VOT),incorporating Virtual Open Scenario(VOS)and User in Scenarios(UIS)concepts.By employing modeling and simulation technologies in the early stages of aircraft development and design,a virtual environment can be constructed,allowing aircraft users to participate more closely and conveniently in the design process.Virtual tests conducted by users within the mission context provide data on mission effectiveness and critical user feedback.This paper outlines the main components of the virtual operational test process and related conceptual methods,and discusses an open support system framework that supports VOT.The effectiveness and adaptability of the method are demonstrated through two case studies:a beyond-visual-range air combat scenario and a helicopter ground attack scenario.These case studies demonstrate the evaluation of aircraft mission effectiveness and the sensitivity analysis and optimization of design and operational parameters based on VOT.展开更多
[Objective] This study was to screen the economic or stable PCR system of rice and detect the generality of the selected system in different molecular markers based on PCR.[Method] With DNA extracted from rice leaves ...[Objective] This study was to screen the economic or stable PCR system of rice and detect the generality of the selected system in different molecular markers based on PCR.[Method] With DNA extracted from rice leaves by CTAB method as the template,PCR system was optimized by L16(45)orthogonal design.[Result] Clear bands were amplified from 16 different combinations,but the amplification effects and yields had difference.The most economic and applicable system was as follows:20 ng DNA template,150 μmol/L dNT...展开更多
Listening importance attracts researchers' attention.Based on testing responses,typical listening items are introduced and suggestions are proposed to improve listing teaching.
For optimal design of constant stress accelerated life test（CSALT） with two-stress, if the stresses could not reach the highest levels simultaneously, the test region becomes non-rectangular. For optimal CSALT desig...For optimal design of constant stress accelerated life test（CSALT） with two-stress, if the stresses could not reach the highest levels simultaneously, the test region becomes non-rectangular. For optimal CSALT design on non-rectangle test region, the present method is only focused on non-rectangle test region with simple boundary, and the optimization algorithm is based on experience which can not ensure to obtain the optimal plan. In this paper, considering the linear-extreme value model and the optimization goal to minimize the variance of lifetime estimate under normal stress, the optimal design method of two-stress type-I censored CSALT plan on general non-rectangular test region is proposed. First, two properties of optimal test plans are proved and the relationship of all the optimal test plans is determined analytically. Then, on the basis of the two properties, the optimal problem is simplified and the optimal design method of two-stress CSALT plan on general non-rectangular test region is proposed. Finally, a numerical example is used to illustrate the feasibility and effectiveness of the method, The result shows that the proposed method could obtain the optimal test plan on non-rectangular test regions with arbitrary boundaries. This research provides the theory and method for two-stress optimal CSALT planning on non-rectangular test regions.展开更多
Accelerated life test(ALT) is currently the main method of assessing product reliability rapidly, and the design of efficient test plans is a critical step to ensure that ALTs can assess the product reliability accura...Accelerated life test(ALT) is currently the main method of assessing product reliability rapidly, and the design of efficient test plans is a critical step to ensure that ALTs can assess the product reliability accurately, quickly, and economically. With the promotion of the national strategy of civil-military integration, ALT will be widely used in the research and development(R&D) of various types of products, and the ALT plan design theory will face further challenges. To aid engineers in selecting appropriate theories and to stimulate researchers to develop the theories required in engineering, with focus on the demands for theory research that arise from the implementation of ALT, this paper reviews and summarizes the development of ALT plan design theory. The development of the theory and method for planning optimal ALT for location-scale distribution, which is the most applied and mature theory of designing the optimal ALT plan, are described in detail. Taking this as the center of radiation, some problems that ALT now faces, such as the verification of the statistical model, limitation of sample size, solutions of resource limits, optimization of the test arrangement, and management of product complexity, are discussed, and the general ideas and methods of solving these problems are analyzed. Suggestions for selecting appropriate ALT plan design theories are proposed, and the urgent solved theory problems and opinions of their solutions are proposed. Based on the principle of convenience for engineers to select appropriate methods according to the problems found in practice, this paper reviews the development of optimal ALT plan design theory by taking the engineering problems arising from the ALT implementation as the main thread, provides guidelines on selecting appropriate theories for engineers, and proposes opinions about the urgent solved theory problems for researchers.展开更多
For planning optimum multiple stresses accelerated life test plans, a commonly followed guiding principle is that all parameters of the life-stress relationship should be estimated, and the number of the stress level ...For planning optimum multiple stresses accelerated life test plans, a commonly followed guiding principle is that all parameters of the life-stress relationship should be estimated, and the number of the stress level combinations must be no less than the number of parameters of the life-stress relationship. However, the general objective of an accelerated life test（ALT） is to assess thep-th quantile of the product life distribution under normal stress. For this objective,estimating all model parameters is not necessary, and this will increase the cost of test. Based on the theoretical conclusion that the stress level combinations of the optimum multiple stresses ALT plan locate on a straight line through the origin of coordinate, it is proposed that a design idea of planning the optimum multiple stresses ALT plan through transforming the problem of designing an optimum multiple stresses ALT plan to designing an optimum single stress ALT plan. Moreover, a method of planning the optimum multiple stresses ALT plan which can avoid estimating all model parameters is established. An example shows that, the proposed plan which only has two stress level combinations could achieve an accuracy no less than the traditional plan, and save the test time and cost on one stress level combination at least; when the actual product life is less than the design value, even the deviation of the model initial parameters value is up to 20%, the variance of the estimation of thep-th quantile of the proposed plan is still smaller than the traditional plans approximately 25%. A design method is provided for planning the optimum multiple stresses ALT which uses the statistical optimum degenerate test plan as the optimum multiple stresses accelerated life test plan.展开更多
An efficient design-for-testability （DFT） technique is proposed to achieve low overhead for scan-based delay fault testing. Existing techniques for delay test such as skewed-load or broadside make the test generatio...An efficient design-for-testability （DFT） technique is proposed to achieve low overhead for scan-based delay fault testing. Existing techniques for delay test such as skewed-load or broadside make the test generation process complex and produce lower coverage for scan-based designs as compared with non-scan designs, whereas techniques such as enhanced-scan test can make the test easy but need an extra holding latch to add substantial hardware overhead. A new tri-state holding logic is presented to replace the common holding latch in enhanced-scan test to get a substantial low hardware overhead. This scheme can achieve low delay overhead by avoiding the holding latch on the critical timing scan path. What＇s more, this method can also keep the state and signal activity in the combinational circuit from the scan during data scan-in operation to reduce the power dissipation. Experiment results on a set of ISCAS89 benchmarks show the efficiency of the proposed scheme.展开更多
The robust parameter design method is a traditional approach to robust experimental design that seeks to obtain the optimal combination of factors/levels. To overcome some of the defects of the inflatable wing paramet...The robust parameter design method is a traditional approach to robust experimental design that seeks to obtain the optimal combination of factors/levels. To overcome some of the defects of the inflatable wing parameter design method, this paper proposes an optimization design scheme based on orthogonal testing and support vector machines （SVMs）. Orthogonal testing design is used to estimate the appropriate initial value and variation domain of each variable to decrease the number of iterations and improve the identification accuracy and efficiency. Orthogonal tests consisting of three factors and three levels are designed to analyze the parameters of pressure, uniform applied load and the number of chambers that affect the bending response of inflatable wings. An SVM intelligent model is established and limited orthogonal test swatches are studied. Thus, the precise relationships between each parameter and product quality features, as well the signal-to-noise ratio （SNR）, can be obtained. This can guide general technological design optimization.展开更多
This study presents a Bayesian methodology for de- signing step stress accelerated degradation testing （SSADT） and its application to batteries. First, the simulation-based Bayesian de- sign framework for SSADT is p...This study presents a Bayesian methodology for de- signing step stress accelerated degradation testing （SSADT） and its application to batteries. First, the simulation-based Bayesian de- sign framework for SSADT is presented. Then, by considering his- torical data, specific optimal objectives oriented Kullback-Leibler （KL） divergence is established. A numerical example is discussed to illustrate the design approach. It is assumed that the degrada- tion model （or process） follows a drift Brownian motion; the accele- ration model follows Arrhenius equation; and the corresponding parameters follow normal and Gamma prior distributions. Using the Markov Chain Monte Carlo （MCMC） method and WinBUGS software, the comparison shows that KL divergence is better than quadratic loss for optimal criteria. Further, the effect of simulation outiiers on the optimization plan is analyzed and the preferred sur- face fitting algorithm is chosen. At the end of the paper, a NASA lithium-ion battery dataset is used as historical information and the KL divergence oriented Bayesian design is compared with maxi- mum likelihood theory oriented locally optimal design. The results show that the proposed method can provide a much better testing plan for this engineering application.展开更多
This paper describes the application of orthogonal test design coupled with non-linear regression analysis to optimize abrasive suspension jet （AS J） cutting process and construct its cutting model. Orthogonal test ...This paper describes the application of orthogonal test design coupled with non-linear regression analysis to optimize abrasive suspension jet （AS J） cutting process and construct its cutting model. Orthogonal test design is applied to cutting stainless steel. Through range analysis on experiment results, the optimal process conditions for the cutting depth and the kerr ratio of the bottom width to the top width can be determined. In addition, the analysis of ranges and variances are all employed to identify various factors： traverse rate, working pressure, nozzle diameter, standoff distance which denote the importance order of the cutting parameters affecting cutting depth and the kerf ratio of the bottom width to the top width. ~rthermore, non-linear regression analysis is used to establish the mathematical models of the cutting parameters based on the cutting depth and the kerr ratio. Finally, the verification experiments of cutting parameters＇ effect on cutting performance, which show that optimized cutting parameters and cutting model can significantly improve the prediction of the cutting ability and quality of ASJ.展开更多
Well-designed airfoil is very important for high-performance rotor.This paper developed an efficient multi-objective and multi-constraint optimization design system for rotor airfoils based on RANS analysis,and verifi...Well-designed airfoil is very important for high-performance rotor.This paper developed an efficient multi-objective and multi-constraint optimization design system for rotor airfoils based on RANS analysis,and verified the performance of the optimized airfoil.Using CRA09-A as the baseline rotor airfoil,the CRA09-B optimized rotor airfoil was designed successfully.Combined with the foundation of high-precision rotor airfoil stationary test technology,the CRA09-B and CRA09-A rotor airfoils were tested in the S3 MA high-speed wind tunnel of ONERA.In order to correct the aerodynamic data,a single parameter linear wall pressure method is used to consider the tunnel effects.The results indicate that multi-objective and multi-constraint optimization design method developed in this study is reliable,and that CRA09-B optimized airfoil provides better stationary performance than CRA09-A airfoil in terms of maximum lift coefficient and lift-to-drag ratio.展开更多
A novel optical testing target(OTT) with three degrees of freedom(DOFs) is proposed for measuring the tracking performance of a photoelectric theodolite. The main components, such as the azimuth axis system, the pitch...A novel optical testing target(OTT) with three degrees of freedom(DOFs) is proposed for measuring the tracking performance of a photoelectric theodolite. The main components, such as the azimuth axis system, the pitching axis system, the linear motion system, and the simulated target generator, are designed. Furthermore, the linear module with the form of a large-span and low-stiffness cantilever beam is strengthened using an integrated optimization method. After the structure is strengthened, the 1 st-order natural frequency increases from 14 Hz to 32 Hz. Finally, a functional test is performed and the results show that compared with a traditional optical test target, the simulated target generated by the novel target is advantageous in practice.展开更多
For the purpose of obtaining satisfactory performance of the non-circular gear & crank-rocker & gear trains (NCCRG) weft insertion mechanism which was proposed in this paper, the ideal kinematic curve of this ...For the purpose of obtaining satisfactory performance of the non-circular gear & crank-rocker & gear trains (NCCRG) weft insertion mechanism which was proposed in this paper, the ideal kinematic curve of this weft insertion mechanism was given, and the reverse solution models of this mechanism were established. A reverse design and simulation software was compiled based on Visual Basic 6.0 to obtain the mechanism parameters, including the pitch curves and tooth profiles of the non-circular gears. A test-bed of this mechanism was developed according to these parameters. The kinematic performance of this weft insertion mechanism was tested by high-speed video tape recorder with its corresponding video analytical software Blaster's MAS. And the test results were identical with the theoretical calculation. Compared with the conjugate cam weft insertion mechanism which is applied on TT96 rapier loom, under the condition of same weft insertion rate, the variation of acceleration of this mechanism is smaller. This novel weft insertion mechanism can meet the requirements of weft insertion on rapier looms with smooth and steady motion.展开更多
Physical model test is an effective way to unveil the dynamic response of a slope under seismic condition.The similarity design is the key of physical model test.An isolated similarity design method for shaking table ...Physical model test is an effective way to unveil the dynamic response of a slope under seismic condition.The similarity design is the key of physical model test.An isolated similarity design method for shaking table tests was proposed and verified in this work.In this method,the relevant physical quantities were divided into several subsystems and subcharacteristic equations for each subsystem were then established based on the Buckingham similarity theory.Large-scale shaking table tests on a reinforced slope were adopted herein to illustrate the application of the proposed isolated similarity design method.The similarity system for the studied slope was divided into four parts in the process of similarity design.The geometrical dimension L,densityρand gravity g were selected as fundamental quantities for the similarity design,and four subcharacteristic equations were established for each subsystem.The dynamic responses of the recorded acceleration and axis force show that the seismic waves propagate well in the model slope.The proposed isolated similarity design method solves the conflict between the similarity requirement for all relevant physical quantities and the difficulty of test model fabrication to satisfy all similarity relations.展开更多
We present an example of applying'need-driven'product design principle to the development of a rapid test kit to detect SARS-COV-2(COVID-19).The tests are intended for use in the field and,longer term,for home...We present an example of applying'need-driven'product design principle to the development of a rapid test kit to detect SARS-COV-2(COVID-19).The tests are intended for use in the field and,longer term,for home use.They detect whether a subject is currently infected with the virus and is infectious.The urgent need for large numbers of tests in field setting imposes constraints such as short test time and lack of access to specialist equipment,laboratories and skilled technicians to perform the test and interpret results.To meet these needs,an antigen test based on RT-LAMP with colorimetric readout was chosen.Direct use of swab sample with no RNA extraction was explored.After extensive experimental study(reported elsewhere),a rapid test kit has been fabricated to satisfy all design criteria.展开更多
There are many various kinds of English language tests in the world,ranging from IELTS(International English Lan⁃guage Testing System)to TOEFL(Test of English as a Foreign Language).All these tests are designed for di...There are many various kinds of English language tests in the world,ranging from IELTS(International English Lan⁃guage Testing System)to TOEFL(Test of English as a Foreign Language).All these tests are designed for different purposes relat⁃ing to various groups of testees.Usually the English language test covers the testing of the four language skills of reading,writing,listening and speaking.The essay will discuss the relationship between the nature of four skills and the test design respectively.展开更多
Anti-ram bollard systems, which are installed around buildings and infrastructure, can prevent unauthorized vehicles from entering, maintain distance from vehicle-borne improvised explosive devices （VBIED） and reduc...Anti-ram bollard systems, which are installed around buildings and infrastructure, can prevent unauthorized vehicles from entering, maintain distance from vehicle-borne improvised explosive devices （VBIED） and reduce the corresponding damage. Compared with a fixed bollard system, a removable bollard system provides more flexibility as it can be removed when needed. This paper first proposes a new type of K4-rated removable anti-ram bollard system. To simulate the collision of a vehicle hitting the bollard system, a finite element model was then built and verified through comparison of numerical simulation results and existing experimental results. Based on the orthogonal design method, the factors influencing the safety and economy of this proposed system were examined and sorted according to their importance. An optimal design scheme was then produced. Finally, to validate the effectiveness of the proposed design scheme, four dynamic impact tests, including two front impact tests and two side impact tests, have been conducted according to BSI Specifications. The residual rotation angles of the specimen are smaller than 30~ and satisfy the requirements of the BSI Specification.展开更多
This paper discusses the modeling design and accuracy analysis of a single stage steam centrifugal compressor for China′S first seawater desalinization plant, and gives a brief presentation on the closed loop vapou...This paper discusses the modeling design and accuracy analysis of a single stage steam centrifugal compressor for China′S first seawater desalinization plant, and gives a brief presentation on the closed loop vapour test platform designed and constructed for qualification of the compress or for performance and operational reliability, and results of tests run with the compressor. Both tests and actual operation show the modeling design is successful, and the compressor achieved and exceeded what was expected in performance. The seawater desalinization plant has run with excellent performance and reliability for several years for the national seawater desalinization demonstration program. This proves it is practical and practicable to develop and design China′s steam centrifugal compressors in series from air centrifugal compressors by maintaining equal specific volume ratio at both inlet and outlet of the compressor.展开更多
By analyzing the shortage of reliability test design and thinking over the producer's risk and consumer's risk, the information fusion technology is used to set up a reliability test design model( RTDM). By an...By analyzing the shortage of reliability test design and thinking over the producer's risk and consumer's risk, the information fusion technology is used to set up a reliability test design model( RTDM). By analyzing the demands and constraint conditions of the RTDM and with applications of Bayesian approach and Monte Carlo method( MCM),this paper puts forward the exponential distributed subsystems and the information fusion technology among them. According to the posteriori risk criteria,formulas of producer's risk and consumer's risk were also inferred,and with the help of Matlab software,selection of the optimum test plan was solved. Finally,validity of the model had been proved by a test of series parallel system.展开更多
基金supported by National Natural Science Foundation of China(Nos.12222513,12105345,12175292,and No.12405178)。
文摘Radio frequency(RF)cavities for advanced storage rings,also known as diffraction-limited storage rings,are under development.To this end,a competitive and promising approach involves normal-conducting continuous wave technology.The design and preliminary test of a 499.654 MHz RF cavity for the Wuhan Advanced Light Source(WALS)based on specific beam parameters were conducted at the SSRF.Multi-objective evolutionary algorithms have been utilized to optimize RF properties,such as the power loss and power density,resulting in better performance in the continuous wave mode.Further improvements were made to suppress multipacting effects in the working area.To operate stably with the beam,higher-order mode dampers were applied to better address the coupling bunch instability than in previous designs,along with thermal analysis to achieve the desired RF performance.Comprehensive simulation studies demonstrated the stable operation of the RF cavity at the defined beam parameters in the WALS design.A prototype RF cavity was then developed,and the RF performance results in a low-power test showed good agreement with the design and simulation,exhibiting readiness for high-power experiments and operation.
文摘The early involvement of test and evaluation can significantly reduce the cost of modifying issues and errors found in the later stages of aircraft development and design process.This paper presents a methodology for aircraft mission effectiveness evaluation and design space exploration based on Virtual Operational Test(VOT),incorporating Virtual Open Scenario(VOS)and User in Scenarios(UIS)concepts.By employing modeling and simulation technologies in the early stages of aircraft development and design,a virtual environment can be constructed,allowing aircraft users to participate more closely and conveniently in the design process.Virtual tests conducted by users within the mission context provide data on mission effectiveness and critical user feedback.This paper outlines the main components of the virtual operational test process and related conceptual methods,and discusses an open support system framework that supports VOT.The effectiveness and adaptability of the method are demonstrated through two case studies:a beyond-visual-range air combat scenario and a helicopter ground attack scenario.These case studies demonstrate the evaluation of aircraft mission effectiveness and the sensitivity analysis and optimization of design and operational parameters based on VOT.
基金Supported by the Key Project from Department of Science and Technology of Heilongjiang Province(GA06B102-3-4)the Key Project from Heilongjiang Provincial Reclamation General Administration(HNKXIV-01-01-02)~~
文摘[Objective] This study was to screen the economic or stable PCR system of rice and detect the generality of the selected system in different molecular markers based on PCR.[Method] With DNA extracted from rice leaves by CTAB method as the template,PCR system was optimized by L16(45)orthogonal design.[Result] Clear bands were amplified from 16 different combinations,but the amplification effects and yields had difference.The most economic and applicable system was as follows:20 ng DNA template,150 μmol/L dNT...
文摘Listening importance attracts researchers' attention.Based on testing responses,typical listening items are introduced and suggestions are proposed to improve listing teaching.
基金supported by National Natural Science Foundation of China(Grant Nos. 50935002, 51075370, 51105341)National Hi-tech Research and Development Program of China(863 Program, Grant No. 2007AA04Z409)+1 种基金the Technology Foundation of National Defense ProgramZhejiang Provincial Natural Science Foundation of China (Grant Nos. Y1100777, Y1080762)
文摘For optimal design of constant stress accelerated life test（CSALT） with two-stress, if the stresses could not reach the highest levels simultaneously, the test region becomes non-rectangular. For optimal CSALT design on non-rectangle test region, the present method is only focused on non-rectangle test region with simple boundary, and the optimization algorithm is based on experience which can not ensure to obtain the optimal plan. In this paper, considering the linear-extreme value model and the optimization goal to minimize the variance of lifetime estimate under normal stress, the optimal design method of two-stress type-I censored CSALT plan on general non-rectangular test region is proposed. First, two properties of optimal test plans are proved and the relationship of all the optimal test plans is determined analytically. Then, on the basis of the two properties, the optimal problem is simplified and the optimal design method of two-stress CSALT plan on general non-rectangular test region is proposed. Finally, a numerical example is used to illustrate the feasibility and effectiveness of the method, The result shows that the proposed method could obtain the optimal test plan on non-rectangular test regions with arbitrary boundaries. This research provides the theory and method for two-stress optimal CSALT planning on non-rectangular test regions.
基金Supported by National Natural Science Foundation of China(Grant No.51275480,51305402,51405447)International Science & Technology Cooperation Program of China(Grant No.2015DFA71400)
文摘Accelerated life test(ALT) is currently the main method of assessing product reliability rapidly, and the design of efficient test plans is a critical step to ensure that ALTs can assess the product reliability accurately, quickly, and economically. With the promotion of the national strategy of civil-military integration, ALT will be widely used in the research and development(R&D) of various types of products, and the ALT plan design theory will face further challenges. To aid engineers in selecting appropriate theories and to stimulate researchers to develop the theories required in engineering, with focus on the demands for theory research that arise from the implementation of ALT, this paper reviews and summarizes the development of ALT plan design theory. The development of the theory and method for planning optimal ALT for location-scale distribution, which is the most applied and mature theory of designing the optimal ALT plan, are described in detail. Taking this as the center of radiation, some problems that ALT now faces, such as the verification of the statistical model, limitation of sample size, solutions of resource limits, optimization of the test arrangement, and management of product complexity, are discussed, and the general ideas and methods of solving these problems are analyzed. Suggestions for selecting appropriate ALT plan design theories are proposed, and the urgent solved theory problems and opinions of their solutions are proposed. Based on the principle of convenience for engineers to select appropriate methods according to the problems found in practice, this paper reviews the development of optimal ALT plan design theory by taking the engineering problems arising from the ALT implementation as the main thread, provides guidelines on selecting appropriate theories for engineers, and proposes opinions about the urgent solved theory problems for researchers.
基金Supported by National Natural Science Foundation of China (Grant Nos.50935002,51075370,51105341,51275480,51305402)Zhejiang Provincial Natural Science Foundation of China (Grant No.Y1100777)+1 种基金Zhejiang Provincial Key Science and Technology Innovation Team (Grant No.2010R50005)Key Program of Science and Technology of Sichuan Provincial Education Department,China (Grant No.14ZA0005)
文摘For planning optimum multiple stresses accelerated life test plans, a commonly followed guiding principle is that all parameters of the life-stress relationship should be estimated, and the number of the stress level combinations must be no less than the number of parameters of the life-stress relationship. However, the general objective of an accelerated life test（ALT） is to assess thep-th quantile of the product life distribution under normal stress. For this objective,estimating all model parameters is not necessary, and this will increase the cost of test. Based on the theoretical conclusion that the stress level combinations of the optimum multiple stresses ALT plan locate on a straight line through the origin of coordinate, it is proposed that a design idea of planning the optimum multiple stresses ALT plan through transforming the problem of designing an optimum multiple stresses ALT plan to designing an optimum single stress ALT plan. Moreover, a method of planning the optimum multiple stresses ALT plan which can avoid estimating all model parameters is established. An example shows that, the proposed plan which only has two stress level combinations could achieve an accuracy no less than the traditional plan, and save the test time and cost on one stress level combination at least; when the actual product life is less than the design value, even the deviation of the model initial parameters value is up to 20%, the variance of the estimation of thep-th quantile of the proposed plan is still smaller than the traditional plans approximately 25%. A design method is provided for planning the optimum multiple stresses ALT which uses the statistical optimum degenerate test plan as the optimum multiple stresses accelerated life test plan.
基金This project was supported by the National Natural Science Foundation of China (90407007).
文摘An efficient design-for-testability （DFT） technique is proposed to achieve low overhead for scan-based delay fault testing. Existing techniques for delay test such as skewed-load or broadside make the test generation process complex and produce lower coverage for scan-based designs as compared with non-scan designs, whereas techniques such as enhanced-scan test can make the test easy but need an extra holding latch to add substantial hardware overhead. A new tri-state holding logic is presented to replace the common holding latch in enhanced-scan test to get a substantial low hardware overhead. This scheme can achieve low delay overhead by avoiding the holding latch on the critical timing scan path. What＇s more, this method can also keep the state and signal activity in the combinational circuit from the scan during data scan-in operation to reduce the power dissipation. Experiment results on a set of ISCAS89 benchmarks show the efficiency of the proposed scheme.
文摘The robust parameter design method is a traditional approach to robust experimental design that seeks to obtain the optimal combination of factors/levels. To overcome some of the defects of the inflatable wing parameter design method, this paper proposes an optimization design scheme based on orthogonal testing and support vector machines （SVMs）. Orthogonal testing design is used to estimate the appropriate initial value and variation domain of each variable to decrease the number of iterations and improve the identification accuracy and efficiency. Orthogonal tests consisting of three factors and three levels are designed to analyze the parameters of pressure, uniform applied load and the number of chambers that affect the bending response of inflatable wings. An SVM intelligent model is established and limited orthogonal test swatches are studied. Thus, the precise relationships between each parameter and product quality features, as well the signal-to-noise ratio （SNR）, can be obtained. This can guide general technological design optimization.
基金supported by the National Natural Science Foundation of China(61104182)
文摘This study presents a Bayesian methodology for de- signing step stress accelerated degradation testing （SSADT） and its application to batteries. First, the simulation-based Bayesian de- sign framework for SSADT is presented. Then, by considering his- torical data, specific optimal objectives oriented Kullback-Leibler （KL） divergence is established. A numerical example is discussed to illustrate the design approach. It is assumed that the degrada- tion model （or process） follows a drift Brownian motion; the accele- ration model follows Arrhenius equation; and the corresponding parameters follow normal and Gamma prior distributions. Using the Markov Chain Monte Carlo （MCMC） method and WinBUGS software, the comparison shows that KL divergence is better than quadratic loss for optimal criteria. Further, the effect of simulation outiiers on the optimization plan is analyzed and the preferred sur- face fitting algorithm is chosen. At the end of the paper, a NASA lithium-ion battery dataset is used as historical information and the KL divergence oriented Bayesian design is compared with maxi- mum likelihood theory oriented locally optimal design. The results show that the proposed method can provide a much better testing plan for this engineering application.
基金supported by the Science and Technology Development Foundation of Shanghai Municipal Science and Technology Commission (Grant No.037252022)
文摘This paper describes the application of orthogonal test design coupled with non-linear regression analysis to optimize abrasive suspension jet （AS J） cutting process and construct its cutting model. Orthogonal test design is applied to cutting stainless steel. Through range analysis on experiment results, the optimal process conditions for the cutting depth and the kerr ratio of the bottom width to the top width can be determined. In addition, the analysis of ranges and variances are all employed to identify various factors： traverse rate, working pressure, nozzle diameter, standoff distance which denote the importance order of the cutting parameters affecting cutting depth and the kerf ratio of the bottom width to the top width. ~rthermore, non-linear regression analysis is used to establish the mathematical models of the cutting parameters based on the cutting depth and the kerr ratio. Finally, the verification experiments of cutting parameters＇ effect on cutting performance, which show that optimized cutting parameters and cutting model can significantly improve the prediction of the cutting ability and quality of ASJ.
基金supported by the National Natural Science Foundation of China(No.11902335)。
文摘Well-designed airfoil is very important for high-performance rotor.This paper developed an efficient multi-objective and multi-constraint optimization design system for rotor airfoils based on RANS analysis,and verified the performance of the optimized airfoil.Using CRA09-A as the baseline rotor airfoil,the CRA09-B optimized rotor airfoil was designed successfully.Combined with the foundation of high-precision rotor airfoil stationary test technology,the CRA09-B and CRA09-A rotor airfoils were tested in the S3 MA high-speed wind tunnel of ONERA.In order to correct the aerodynamic data,a single parameter linear wall pressure method is used to consider the tunnel effects.The results indicate that multi-objective and multi-constraint optimization design method developed in this study is reliable,and that CRA09-B optimized airfoil provides better stationary performance than CRA09-A airfoil in terms of maximum lift coefficient and lift-to-drag ratio.
基金supported by the Third Phase of the Innovation Project Funding of Changchun Institute of Optics,Fine Mechanics and Physics,Chinese Academy of Science(No.061X20C060)
文摘A novel optical testing target(OTT) with three degrees of freedom(DOFs) is proposed for measuring the tracking performance of a photoelectric theodolite. The main components, such as the azimuth axis system, the pitching axis system, the linear motion system, and the simulated target generator, are designed. Furthermore, the linear module with the form of a large-span and low-stiffness cantilever beam is strengthened using an integrated optimization method. After the structure is strengthened, the 1 st-order natural frequency increases from 14 Hz to 32 Hz. Finally, a functional test is performed and the results show that compared with a traditional optical test target, the simulated target generated by the novel target is advantageous in practice.
基金National Natural Science Foundation of China(No.50875243)
文摘For the purpose of obtaining satisfactory performance of the non-circular gear & crank-rocker & gear trains (NCCRG) weft insertion mechanism which was proposed in this paper, the ideal kinematic curve of this weft insertion mechanism was given, and the reverse solution models of this mechanism were established. A reverse design and simulation software was compiled based on Visual Basic 6.0 to obtain the mechanism parameters, including the pitch curves and tooth profiles of the non-circular gears. A test-bed of this mechanism was developed according to these parameters. The kinematic performance of this weft insertion mechanism was tested by high-speed video tape recorder with its corresponding video analytical software Blaster's MAS. And the test results were identical with the theoretical calculation. Compared with the conjugate cam weft insertion mechanism which is applied on TT96 rapier loom, under the condition of same weft insertion rate, the variation of acceleration of this mechanism is smaller. This novel weft insertion mechanism can meet the requirements of weft insertion on rapier looms with smooth and steady motion.
基金financially supported by National Natural Science Foundation of China(51708163 and 41907247)Hainan Provincial Natural Science Foundation of China(520MS018)the foundation from the State Key Laboratory of Geohazard Prevention and Geoenvironment Protection(SKLGP2021K008)。
文摘Physical model test is an effective way to unveil the dynamic response of a slope under seismic condition.The similarity design is the key of physical model test.An isolated similarity design method for shaking table tests was proposed and verified in this work.In this method,the relevant physical quantities were divided into several subsystems and subcharacteristic equations for each subsystem were then established based on the Buckingham similarity theory.Large-scale shaking table tests on a reinforced slope were adopted herein to illustrate the application of the proposed isolated similarity design method.The similarity system for the studied slope was divided into four parts in the process of similarity design.The geometrical dimension L,densityρand gravity g were selected as fundamental quantities for the similarity design,and four subcharacteristic equations were established for each subsystem.The dynamic responses of the recorded acceleration and axis force show that the seismic waves propagate well in the model slope.The proposed isolated similarity design method solves the conflict between the similarity requirement for all relevant physical quantities and the difficulty of test model fabrication to satisfy all similarity relations.
文摘We present an example of applying'need-driven'product design principle to the development of a rapid test kit to detect SARS-COV-2(COVID-19).The tests are intended for use in the field and,longer term,for home use.They detect whether a subject is currently infected with the virus and is infectious.The urgent need for large numbers of tests in field setting imposes constraints such as short test time and lack of access to specialist equipment,laboratories and skilled technicians to perform the test and interpret results.To meet these needs,an antigen test based on RT-LAMP with colorimetric readout was chosen.Direct use of swab sample with no RNA extraction was explored.After extensive experimental study(reported elsewhere),a rapid test kit has been fabricated to satisfy all design criteria.
文摘There are many various kinds of English language tests in the world,ranging from IELTS(International English Lan⁃guage Testing System)to TOEFL(Test of English as a Foreign Language).All these tests are designed for different purposes relat⁃ing to various groups of testees.Usually the English language test covers the testing of the four language skills of reading,writing,listening and speaking.The essay will discuss the relationship between the nature of four skills and the test design respectively.
文摘Anti-ram bollard systems, which are installed around buildings and infrastructure, can prevent unauthorized vehicles from entering, maintain distance from vehicle-borne improvised explosive devices （VBIED） and reduce the corresponding damage. Compared with a fixed bollard system, a removable bollard system provides more flexibility as it can be removed when needed. This paper first proposes a new type of K4-rated removable anti-ram bollard system. To simulate the collision of a vehicle hitting the bollard system, a finite element model was then built and verified through comparison of numerical simulation results and existing experimental results. Based on the orthogonal design method, the factors influencing the safety and economy of this proposed system were examined and sorted according to their importance. An optimal design scheme was then produced. Finally, to validate the effectiveness of the proposed design scheme, four dynamic impact tests, including two front impact tests and two side impact tests, have been conducted according to BSI Specifications. The residual rotation angles of the specimen are smaller than 30~ and satisfy the requirements of the BSI Specification.
文摘This paper discusses the modeling design and accuracy analysis of a single stage steam centrifugal compressor for China′S first seawater desalinization plant, and gives a brief presentation on the closed loop vapour test platform designed and constructed for qualification of the compress or for performance and operational reliability, and results of tests run with the compressor. Both tests and actual operation show the modeling design is successful, and the compressor achieved and exceeded what was expected in performance. The seawater desalinization plant has run with excellent performance and reliability for several years for the national seawater desalinization demonstration program. This proves it is practical and practicable to develop and design China′s steam centrifugal compressors in series from air centrifugal compressors by maintaining equal specific volume ratio at both inlet and outlet of the compressor.
基金National Natural Science Foundation of China(No.70971133)
文摘By analyzing the shortage of reliability test design and thinking over the producer's risk and consumer's risk, the information fusion technology is used to set up a reliability test design model( RTDM). By analyzing the demands and constraint conditions of the RTDM and with applications of Bayesian approach and Monte Carlo method( MCM),this paper puts forward the exponential distributed subsystems and the information fusion technology among them. According to the posteriori risk criteria,formulas of producer's risk and consumer's risk were also inferred,and with the help of Matlab software,selection of the optimum test plan was solved. Finally,validity of the model had been proved by a test of series parallel system.
