During deep water oil well testing, the low temperature environment is easy to cause wax precipitation, which affects the normal operation of the test and increases operating costs and risks. Therefore, a numerical me...During deep water oil well testing, the low temperature environment is easy to cause wax precipitation, which affects the normal operation of the test and increases operating costs and risks. Therefore, a numerical method for predicting the wax precipitation region in oil strings was proposed based on the temperature and pressure fields of deep water test string and the wax precipitation calculation model. And the factors affecting the wax precipitation region were analyzed. The results show that: the wax precipitation region decreases with the increase of production rate, and increases with the decrease of geothermal gradient, increase of water depth and drop of water-cut of produced fluid, and increases slightly with the increase of formation pressure. Due to the effect of temperature and pressure fields, wax precipitation region is large in test strings at the beginning of well production. Wax precipitation region gradually increases with the increase of shut-in time. These conclusions can guide wax prevention during the testing of deep water oil well, to ensure the success of the test.展开更多
Software testing is a critical phase due to misconceptions about ambiguities in the requirements during specification,which affect the testing process.Therefore,it is difficult to identify all faults in software.As re...Software testing is a critical phase due to misconceptions about ambiguities in the requirements during specification,which affect the testing process.Therefore,it is difficult to identify all faults in software.As requirement changes continuously,it increases the irrelevancy and redundancy during testing.Due to these challenges;fault detection capability decreases and there arises a need to improve the testing process,which is based on changes in requirements specification.In this research,we have developed a model to resolve testing challenges through requirement prioritization and prediction in an agile-based environment.The research objective is to identify the most relevant and meaningful requirements through semantic analysis for correct change analysis.Then compute the similarity of requirements through case-based reasoning,which predicted the requirements for reuse and restricted to error-based requirements.Afterward,the apriori algorithm mapped out requirement frequency to select relevant test cases based on frequently reused or not reused test cases to increase the fault detection rate.Furthermore,the proposed model was evaluated by conducting experiments.The results showed that requirement redundancy and irrelevancy improved due to semantic analysis,which correctly predicted the requirements,increasing the fault detection rate and resulting in high user satisfaction.The predicted requirements are mapped into test cases,increasing the fault detection rate after changes to achieve higher user satisfaction.Therefore,the model improves the redundancy and irrelevancy of requirements by more than 90%compared to other clustering methods and the analytical hierarchical process,achieving an 80%fault detection rate at an earlier stage.Hence,it provides guidelines for practitioners and researchers in the modern era.In the future,we will provide the working prototype of this model for proof of concept.展开更多
IEEE 1012 [1] describes the SDLC phase activities for software independent verification and validation (IV & V) for nuclear power plant in truly general and conceptual manner, which requires the upward and/or down...IEEE 1012 [1] describes the SDLC phase activities for software independent verification and validation (IV & V) for nuclear power plant in truly general and conceptual manner, which requires the upward and/or downward tailoring on its interpretation for practical IV & V. It contains crucial and encompassing check points and guidelines to analyze the design integrity, without addressing the formalized and the specific criteria for IV & V activities confirming the technical integrity. It is necessary to list up the inspection viewpoint via interpretation of the standard that is practical review points checking design consistency. For fruitful IV & V of Control Element Driving Mechanism Control System (CEDMCS) software for Yonggwang Nuclear Power Plant unit 3 & 4, the specific viewpoints and approach are necessary based on the guidelines of IEEE 1012 to enhance the system quality by considering the level of implementation of the theoretical and the practical IV & V. Additionally IV & V guideline of IEEE 1012 does not specifically provide the concrete measure considering the system characteristics of CEDMCS. This paper provides the seven (7) characteristic criteria for CEDMCS IV & V, and by applying these viewpoints, the design analysis such as function, performance, interface and exception, backward and forward requirement traceability analysis has been conducted. The requirement, design, implementation, and test phase were only considered for IV & V in this project. This article also provides the translation of code to map theoretical verification and validation into practical verification and validation. This paper emphasizes the necessity of the intensive design inspection and walkthrough for requirement phase to resolve the design faults because the IV & V of early phase of SDLC obviously contributes to find out most of critical design inconsistency. Especially for test phase IV & V, it is strongly recommended to prepare the test plan document which is going to be the basis for the test coverage selection and test strategy. This test plan document should be based on the critical characteristics of function and performance of CEDMCS. Also to guarantee the independency of V & V organization participating in this project, and to acquire the full package of design details for IV & V, the systematic approach and efforts with an aspect of management is highlighted among the participants.展开更多
"Social event driving" has become a way to promote urban development, create urban public spaces and create a city image. As one of the important big cities in northeastern China, Harbin enjoys the reputatio..."Social event driving" has become a way to promote urban development, create urban public spaces and create a city image. As one of the important big cities in northeastern China, Harbin enjoys the reputation of "The Music City", and its public space development is inextricably linked with the driving of music culture. This paper started with the analysis of the correlation between the development of urban public spaces and the development of music culture in Harbin, and studied the influence and driving role of music culture on the construction and development of urban public spaces.展开更多
In this study,we used the short-distance mobility vehicles(electric wheelchair)WHILL,which is sold as a mobility support device rather than a welfare care device,and conducted test rides on campus and on public roads....In this study,we used the short-distance mobility vehicles(electric wheelchair)WHILL,which is sold as a mobility support device rather than a welfare care device,and conducted test rides on campus and on public roads.The participants in the experiment were 10 healthy men and women in their 20s to 60s who did not use electric wheelchairs in their daily lives.The results showed that about half of the experiment participants did not feel anxious about operating WHILL.On the other hand,many participants felt uneasy about the operation of moving backward diagonally.The WHILL’s steering wheel was easy to operate,and it was also very comfortable during the test drive.Before and after the test drive,the impression evaluation of WHILL changed significantly from negative to positive.An improved model of WHILL was proposed based on the results of the questionnaire survey and interview survey after the test drive.展开更多
In underground engineering with complex conditions,the bolt(cable)anchorage support system is in an environment where static and dynamic stresses coexist,under the action of geological conditions such as high stresses...In underground engineering with complex conditions,the bolt(cable)anchorage support system is in an environment where static and dynamic stresses coexist,under the action of geological conditions such as high stresses and strong disturbances and construction conditions such as the application of high prestress.It is essential to study the support components performance under dynamic-static coupling conditions.Based on this,a multi-functional anchorage support dynamic-static coupling performance test system(MAC system)is developed,which can achieve 7 types of testing functions,including single component performance,anchored net performance,anchored rock performance and so on.The bolt and cable mechanical tests are conducted by MAC system under different prestress levels.The results showed that compared to the non-prestress condition,the impact resistance performance of prestressed bolts(cables)is significantly reduced.In the prestress range of 50–160 k N,the maximum reduction rate of impact energy resisted by different types of bolts is 53.9%–61.5%compared to non-prestress condition.In the prestress range of 150–300 k N,the impact energy resisted by high-strength cable is reduced by76.8%–84.6%compared to non-prestress condition.The MAC system achieves dynamic-static coupling performance test,which provide an effective means for the design of anchorage support system.展开更多
To improve the automation level of the vehicle drive axle test and better simulate a vehicle＇s actual operation, an advanced test machine has been developed. The load system of the machine consists of hand brakes and...To improve the automation level of the vehicle drive axle test and better simulate a vehicle＇s actual operation, an advanced test machine has been developed. The load system of the machine consists of hand brakes and electric cylinders. It is simple-structured and low-cost. The major motor of the machine is controlled by a transducer and its speed can be adjusted easily. In addition, the programmed machine can automatically test such parameters as the grinding condition, the differential speed, the noise level, etc. It can also adjust the test procedures according to different requirements. Detailed discussion of the structure and mechanism of the test machine is given in this paper.展开更多
This white paper explores three popular development methodologies for network softwarization: DevOps, NetOps, and Verification. The paper compares and contrasts the strengths and weaknesses of each approach and provid...This white paper explores three popular development methodologies for network softwarization: DevOps, NetOps, and Verification. The paper compares and contrasts the strengths and weaknesses of each approach and provides recommendations for organizations looking to adopt network softwarization.展开更多
Aim:To elucidate the distribution and regulation of Neuropeptide Y(NPY)gene expression in testes under physiologi- cal and pathophysiological conditions,such as testicular development,fasting and experimental cryptorc...Aim:To elucidate the distribution and regulation of Neuropeptide Y(NPY)gene expression in testes under physiologi- cal and pathophysiological conditions,such as testicular development,fasting and experimental cryptorchidism. Methods:In the first experiment,C57BL/6J male mice at the ages of 3 days as well as 2,3,5 and 8 weeks were used. In the second and third experiments,adult C57BL/6J male mice were subjected to fasting for 48 h and experimental cryptorchidism for 72 h.The NPY transcripts were detected by isotopic in situ hybridization histochemistry.Results: The NPY transcripts were exclusively expressed in the interstitial cells regardless of the age groups and experimental conditions.The NPY mRNA levels were found to increase significantly with age(from the neonatal to prepubertal period [P<0.01] and from the prepubetal to postpubertal period [P<0.01]).Food deprivation for 48 h resulted in a significant increase in the NPY mRNA levels in the arcuate nucleus of the hypothalamus(P<0.01),but not in the testes.Experimental cryptorchidism for 72 h failed to regulate the NPY gene expression in the testes.Conclusion: NPY gene expression is distributed in Leydig cells and increases in line with testicular development.The regulation of testicular NPY is different from that of hypothalamic NPY.(Asian J Androl 2006 Jul;8:443-449)展开更多
A method for a vehicle durability emission test using a robot driver insteadof human drivers on the chassis dynamometer is presented. The system architecture of vehicledurability emission test cell, the road load simu...A method for a vehicle durability emission test using a robot driver insteadof human drivers on the chassis dynamometer is presented. The system architecture of vehicledurability emission test cell, the road load simulation strategy and the tele-monitoring systembased on Browser/Client structure are described. Furthermore, the construction of the robot driver,vehicle performance self-learning algorithm, multi-mode vehicle control model and vehicle speedtracking strategy based on fuzzy logic arealso discussed. Besides, the capability of controlparameters self-compensation on-line makes it possible to compensate the wear of vehicle componentsand the variety of clutch true bite point during the long term test. Experimental results show thattherobot driver can be applicable to a wide variety of vehicles and the obtained results stay withina tolerance band of ± 2 km/h. Moreover the robot driver is able to control tested vehicles withgood repeatability and consistency; therefore, this methodpresents a solution to eliminate theuncertainty of emission test results by human drivers and to ensure the accuracy and reliability ofemission test results.展开更多
The outbreak of the SARS-CoV-2 virus in early 2020,known as COVID-19,spread to more than 200 countries and negatively affected the global economic output.Financial activities were primarily depressed,and investors wer...The outbreak of the SARS-CoV-2 virus in early 2020,known as COVID-19,spread to more than 200 countries and negatively affected the global economic output.Financial activities were primarily depressed,and investors were reluctant to start new financial investments while ongoing projects further declined due to the global lockdown to curb the disease.This study analyzes the money supply reaction to the COVID-19 pandemic using a cross-sectional panel of 115 countries.The study used robust least square regression and innovation accounting techniques to get sound parameter estimates.The results show that COVID-19 infected cases are the main contributing factor that obstructs financial activities and decrease money supply.In contrast,an increasing number of recovered cases and COVID-19 testing capabilities gave investors confidence to increase stock trade across countries.The overall forecast trend shows that COVID-19 infected cases and recovered cases followed the U-shaped trend,while COVID-19 critical cases and reported deaths showed a decreasing trend.Finally,the money supply and testing capacity show a positive trend over a period.The study concludes that financial development can be expanded by increasing the testing capacity and functional labs to identify suspected coronavirus cases globally.展开更多
Framework and basic parameters of a test bench for motor drive system of electric vehicle (EV) are illuminated. Two kinds of electric drive models, one was for the electric vehicle drived on real road, the other was f...Framework and basic parameters of a test bench for motor drive system of electric vehicle (EV) are illuminated. Two kinds of electric drive models, one was for the electric vehicle drived on real road, the other was for that on test bench, are put forward. Then, dynamic analysis of these models is made in detail. Inertia matching method of the test bench is researched and some useful formulas and graphs are brought forward. The experiment of an electric bus is introduced in order to explain the usage of this inertia matching method.展开更多
This paper investigates the development of a spoken English test.The nature of speaking test and its design principles are first reviewed.Then the procedure of the test development is elaborated in detail,namely,desig...This paper investigates the development of a spoken English test.The nature of speaking test and its design principles are first reviewed.Then the procedure of the test development is elaborated in detail,namely,design stage,construction stage and try out stage.The challenges facing the development of spoken test are finally discussed.展开更多
This paper presents a holistic methodology for the design of medical device software, which encompasses of a new way of eliciting requirements, system design process, security design guideline, cloud architecture desi...This paper presents a holistic methodology for the design of medical device software, which encompasses of a new way of eliciting requirements, system design process, security design guideline, cloud architecture design, combinatorial testing process and agile project management. The paper uses point of care diagnostics as a case study where the software and hardware must be robust, reliable to provide accurate diagnosis of diseases. As software and software intensive systems are becoming increasingly complex, the impact of failures can lead to significant property damage, or damage to the environment. Within the medical diagnostic device software domain such failures can result in misdiagnosis leading to clinical complications and in some cases death. Software faults can arise due to the interaction among the software, the hardware, third party software and the operating environment. Unanticipated environmental changes and latent coding errors lead to operation faults despite of the fact that usually a significant effort has been expended in the design, verification and validation of the software system. It is becoming increasingly more apparent that one needs to adopt different approaches, which will guarantee that a complex software system meets all safety, security, and reliability requirements, in addition to complying with standards such as IEC 62304. There are many initiatives taken to develop safety and security critical systems, at different development phases and in different contexts, ranging from infrastructure design to device design. Different approaches are implemented to design error free software for safety critical systems. By adopting the strategies and processes presented in this paper one can overcome the challenges in developing error free software for medical devices (or safety critical systems).展开更多
In this paper,a novel component based framework of test system is presented for the new requirements of dynamic changes of test functions and reconfiguration of test resources.The complexity of dynamic reconfiguration...In this paper,a novel component based framework of test system is presented for the new requirements of dynamic changes of test functions and reconfiguration of test resources.The complexity of dynamic reconfiguration arises from the scale, redirection,extensibility and interconnection of components in test system.The paper is started by discussing the component assem- bly based framework which provide the open platform to the deploy of companents and then the script interpreter model is introduced to dynamically create the components and build the test system by analyzing XML based information of test system.A pipeline mod- el is presented to provide the data channels and behavior reflection among the components.Finally,a dynamic reconfigurable test system is implemented on the basis of COM and applied in the remote test and control system of CNC machine.展开更多
基金Supported by the National Key Basic Research and Development Program(973 Program),China(2015CB251205)
文摘During deep water oil well testing, the low temperature environment is easy to cause wax precipitation, which affects the normal operation of the test and increases operating costs and risks. Therefore, a numerical method for predicting the wax precipitation region in oil strings was proposed based on the temperature and pressure fields of deep water test string and the wax precipitation calculation model. And the factors affecting the wax precipitation region were analyzed. The results show that: the wax precipitation region decreases with the increase of production rate, and increases with the decrease of geothermal gradient, increase of water depth and drop of water-cut of produced fluid, and increases slightly with the increase of formation pressure. Due to the effect of temperature and pressure fields, wax precipitation region is large in test strings at the beginning of well production. Wax precipitation region gradually increases with the increase of shut-in time. These conclusions can guide wax prevention during the testing of deep water oil well, to ensure the success of the test.
文摘Software testing is a critical phase due to misconceptions about ambiguities in the requirements during specification,which affect the testing process.Therefore,it is difficult to identify all faults in software.As requirement changes continuously,it increases the irrelevancy and redundancy during testing.Due to these challenges;fault detection capability decreases and there arises a need to improve the testing process,which is based on changes in requirements specification.In this research,we have developed a model to resolve testing challenges through requirement prioritization and prediction in an agile-based environment.The research objective is to identify the most relevant and meaningful requirements through semantic analysis for correct change analysis.Then compute the similarity of requirements through case-based reasoning,which predicted the requirements for reuse and restricted to error-based requirements.Afterward,the apriori algorithm mapped out requirement frequency to select relevant test cases based on frequently reused or not reused test cases to increase the fault detection rate.Furthermore,the proposed model was evaluated by conducting experiments.The results showed that requirement redundancy and irrelevancy improved due to semantic analysis,which correctly predicted the requirements,increasing the fault detection rate and resulting in high user satisfaction.The predicted requirements are mapped into test cases,increasing the fault detection rate after changes to achieve higher user satisfaction.Therefore,the model improves the redundancy and irrelevancy of requirements by more than 90%compared to other clustering methods and the analytical hierarchical process,achieving an 80%fault detection rate at an earlier stage.Hence,it provides guidelines for practitioners and researchers in the modern era.In the future,we will provide the working prototype of this model for proof of concept.
文摘IEEE 1012 [1] describes the SDLC phase activities for software independent verification and validation (IV & V) for nuclear power plant in truly general and conceptual manner, which requires the upward and/or downward tailoring on its interpretation for practical IV & V. It contains crucial and encompassing check points and guidelines to analyze the design integrity, without addressing the formalized and the specific criteria for IV & V activities confirming the technical integrity. It is necessary to list up the inspection viewpoint via interpretation of the standard that is practical review points checking design consistency. For fruitful IV & V of Control Element Driving Mechanism Control System (CEDMCS) software for Yonggwang Nuclear Power Plant unit 3 & 4, the specific viewpoints and approach are necessary based on the guidelines of IEEE 1012 to enhance the system quality by considering the level of implementation of the theoretical and the practical IV & V. Additionally IV & V guideline of IEEE 1012 does not specifically provide the concrete measure considering the system characteristics of CEDMCS. This paper provides the seven (7) characteristic criteria for CEDMCS IV & V, and by applying these viewpoints, the design analysis such as function, performance, interface and exception, backward and forward requirement traceability analysis has been conducted. The requirement, design, implementation, and test phase were only considered for IV & V in this project. This article also provides the translation of code to map theoretical verification and validation into practical verification and validation. This paper emphasizes the necessity of the intensive design inspection and walkthrough for requirement phase to resolve the design faults because the IV & V of early phase of SDLC obviously contributes to find out most of critical design inconsistency. Especially for test phase IV & V, it is strongly recommended to prepare the test plan document which is going to be the basis for the test coverage selection and test strategy. This test plan document should be based on the critical characteristics of function and performance of CEDMCS. Also to guarantee the independency of V & V organization participating in this project, and to acquire the full package of design details for IV & V, the systematic approach and efforts with an aspect of management is highlighted among the participants.
基金Sponsored by Science and Technology Plans of Ministry of Housing and Urban-Rural Development of the People’s Republic of China,and Opening Projects of Beijing Advanced Innovation Center for Future Urban Design,Beijing University of Civil Engineering and Architecture(UDC2017030712)2018 Beijing Municipal University Academic Human Resources Development-Youth Talent Support Program(PXM2018_014212_000043)North China University of Technology "YuYou" Talent Training Program
文摘"Social event driving" has become a way to promote urban development, create urban public spaces and create a city image. As one of the important big cities in northeastern China, Harbin enjoys the reputation of "The Music City", and its public space development is inextricably linked with the driving of music culture. This paper started with the analysis of the correlation between the development of urban public spaces and the development of music culture in Harbin, and studied the influence and driving role of music culture on the construction and development of urban public spaces.
文摘In this study,we used the short-distance mobility vehicles(electric wheelchair)WHILL,which is sold as a mobility support device rather than a welfare care device,and conducted test rides on campus and on public roads.The participants in the experiment were 10 healthy men and women in their 20s to 60s who did not use electric wheelchairs in their daily lives.The results showed that about half of the experiment participants did not feel anxious about operating WHILL.On the other hand,many participants felt uneasy about the operation of moving backward diagonally.The WHILL’s steering wheel was easy to operate,and it was also very comfortable during the test drive.Before and after the test drive,the impression evaluation of WHILL changed significantly from negative to positive.An improved model of WHILL was proposed based on the results of the questionnaire survey and interview survey after the test drive.
基金supported by the National Natural Science Foundation of China(Nos.51927807,52074164,42277174,42077267 and 42177130)the Natural Science Foundation of Shandong Province,China(No.ZR2020JQ23)China University of Mining and Technology(Beijing)Top Innovative Talent Cultivation Fund for Doctoral Students(No.BBJ2023048)。
文摘In underground engineering with complex conditions,the bolt(cable)anchorage support system is in an environment where static and dynamic stresses coexist,under the action of geological conditions such as high stresses and strong disturbances and construction conditions such as the application of high prestress.It is essential to study the support components performance under dynamic-static coupling conditions.Based on this,a multi-functional anchorage support dynamic-static coupling performance test system(MAC system)is developed,which can achieve 7 types of testing functions,including single component performance,anchored net performance,anchored rock performance and so on.The bolt and cable mechanical tests are conducted by MAC system under different prestress levels.The results showed that compared to the non-prestress condition,the impact resistance performance of prestressed bolts(cables)is significantly reduced.In the prestress range of 50–160 k N,the maximum reduction rate of impact energy resisted by different types of bolts is 53.9%–61.5%compared to non-prestress condition.In the prestress range of 150–300 k N,the impact energy resisted by high-strength cable is reduced by76.8%–84.6%compared to non-prestress condition.The MAC system achieves dynamic-static coupling performance test,which provide an effective means for the design of anchorage support system.
文摘To improve the automation level of the vehicle drive axle test and better simulate a vehicle＇s actual operation, an advanced test machine has been developed. The load system of the machine consists of hand brakes and electric cylinders. It is simple-structured and low-cost. The major motor of the machine is controlled by a transducer and its speed can be adjusted easily. In addition, the programmed machine can automatically test such parameters as the grinding condition, the differential speed, the noise level, etc. It can also adjust the test procedures according to different requirements. Detailed discussion of the structure and mechanism of the test machine is given in this paper.
文摘This white paper explores three popular development methodologies for network softwarization: DevOps, NetOps, and Verification. The paper compares and contrasts the strengths and weaknesses of each approach and provides recommendations for organizations looking to adopt network softwarization.
文摘Aim:To elucidate the distribution and regulation of Neuropeptide Y(NPY)gene expression in testes under physiologi- cal and pathophysiological conditions,such as testicular development,fasting and experimental cryptorchidism. Methods:In the first experiment,C57BL/6J male mice at the ages of 3 days as well as 2,3,5 and 8 weeks were used. In the second and third experiments,adult C57BL/6J male mice were subjected to fasting for 48 h and experimental cryptorchidism for 72 h.The NPY transcripts were detected by isotopic in situ hybridization histochemistry.Results: The NPY transcripts were exclusively expressed in the interstitial cells regardless of the age groups and experimental conditions.The NPY mRNA levels were found to increase significantly with age(from the neonatal to prepubertal period [P<0.01] and from the prepubetal to postpubertal period [P<0.01]).Food deprivation for 48 h resulted in a significant increase in the NPY mRNA levels in the arcuate nucleus of the hypothalamus(P<0.01),but not in the testes.Experimental cryptorchidism for 72 h failed to regulate the NPY gene expression in the testes.Conclusion: NPY gene expression is distributed in Leydig cells and increases in line with testicular development.The regulation of testicular NPY is different from that of hypothalamic NPY.(Asian J Androl 2006 Jul;8:443-449)
文摘A method for a vehicle durability emission test using a robot driver insteadof human drivers on the chassis dynamometer is presented. The system architecture of vehicledurability emission test cell, the road load simulation strategy and the tele-monitoring systembased on Browser/Client structure are described. Furthermore, the construction of the robot driver,vehicle performance self-learning algorithm, multi-mode vehicle control model and vehicle speedtracking strategy based on fuzzy logic arealso discussed. Besides, the capability of controlparameters self-compensation on-line makes it possible to compensate the wear of vehicle componentsand the variety of clutch true bite point during the long term test. Experimental results show thattherobot driver can be applicable to a wide variety of vehicles and the obtained results stay withina tolerance band of ± 2 km/h. Moreover the robot driver is able to control tested vehicles withgood repeatability and consistency; therefore, this methodpresents a solution to eliminate theuncertainty of emission test results by human drivers and to ensure the accuracy and reliability ofemission test results.
基金Researchers Supporting Project number(RSP-2020/87),King Saud University,Riyadh,Saudi Arabia.
文摘The outbreak of the SARS-CoV-2 virus in early 2020,known as COVID-19,spread to more than 200 countries and negatively affected the global economic output.Financial activities were primarily depressed,and investors were reluctant to start new financial investments while ongoing projects further declined due to the global lockdown to curb the disease.This study analyzes the money supply reaction to the COVID-19 pandemic using a cross-sectional panel of 115 countries.The study used robust least square regression and innovation accounting techniques to get sound parameter estimates.The results show that COVID-19 infected cases are the main contributing factor that obstructs financial activities and decrease money supply.In contrast,an increasing number of recovered cases and COVID-19 testing capabilities gave investors confidence to increase stock trade across countries.The overall forecast trend shows that COVID-19 infected cases and recovered cases followed the U-shaped trend,while COVID-19 critical cases and reported deaths showed a decreasing trend.Finally,the money supply and testing capacity show a positive trend over a period.The study concludes that financial development can be expanded by increasing the testing capacity and functional labs to identify suspected coronavirus cases globally.
文摘Framework and basic parameters of a test bench for motor drive system of electric vehicle (EV) are illuminated. Two kinds of electric drive models, one was for the electric vehicle drived on real road, the other was for that on test bench, are put forward. Then, dynamic analysis of these models is made in detail. Inertia matching method of the test bench is researched and some useful formulas and graphs are brought forward. The experiment of an electric bus is introduced in order to explain the usage of this inertia matching method.
文摘This paper investigates the development of a spoken English test.The nature of speaking test and its design principles are first reviewed.Then the procedure of the test development is elaborated in detail,namely,design stage,construction stage and try out stage.The challenges facing the development of spoken test are finally discussed.
文摘This paper presents a holistic methodology for the design of medical device software, which encompasses of a new way of eliciting requirements, system design process, security design guideline, cloud architecture design, combinatorial testing process and agile project management. The paper uses point of care diagnostics as a case study where the software and hardware must be robust, reliable to provide accurate diagnosis of diseases. As software and software intensive systems are becoming increasingly complex, the impact of failures can lead to significant property damage, or damage to the environment. Within the medical diagnostic device software domain such failures can result in misdiagnosis leading to clinical complications and in some cases death. Software faults can arise due to the interaction among the software, the hardware, third party software and the operating environment. Unanticipated environmental changes and latent coding errors lead to operation faults despite of the fact that usually a significant effort has been expended in the design, verification and validation of the software system. It is becoming increasingly more apparent that one needs to adopt different approaches, which will guarantee that a complex software system meets all safety, security, and reliability requirements, in addition to complying with standards such as IEC 62304. There are many initiatives taken to develop safety and security critical systems, at different development phases and in different contexts, ranging from infrastructure design to device design. Different approaches are implemented to design error free software for safety critical systems. By adopting the strategies and processes presented in this paper one can overcome the challenges in developing error free software for medical devices (or safety critical systems).
基金Supported by the National Science Foundation of China(Grant No.50275061)the National High Technology Research and Development Program(Grant No.2001AA423230).
文摘In this paper,a novel component based framework of test system is presented for the new requirements of dynamic changes of test functions and reconfiguration of test resources.The complexity of dynamic reconfiguration arises from the scale, redirection,extensibility and interconnection of components in test system.The paper is started by discussing the component assem- bly based framework which provide the open platform to the deploy of companents and then the script interpreter model is introduced to dynamically create the components and build the test system by analyzing XML based information of test system.A pipeline mod- el is presented to provide the data channels and behavior reflection among the components.Finally,a dynamic reconfigurable test system is implemented on the basis of COM and applied in the remote test and control system of CNC machine.
