A more accurate analysis method on working modes is proposed by considering the winding terminal voltage and the eondueting power device as state parameters. For the three-phase hybrid excitation doubly salient machi...A more accurate analysis method on working modes is proposed by considering the winding terminal voltage and the eondueting power device as state parameters. For the three-phase hybrid excitation doubly salient machine （HEDSM） motor and its three-phase full-bridge inverter, in the proposed analytical method, all possible working modes are generally listed. Then, with the H_PWM-L_ON control strategy, the working modes are detailed with eorresponding equivalent circuits. Experimental results verify the robustness of the analysis.展开更多
From electric circuit theory view, a system model of series hybrid electric vehicle was built which uses engine-generator and battery pack as its on-board energy source in this paper. Based on the analysis for the con...From electric circuit theory view, a system model of series hybrid electric vehicle was built which uses engine-generator and battery pack as its on-board energy source in this paper. Based on the analysis for the constant power work mode and constant bus voltage work mode of engine-generator, a third work mode was put forward which combined the advantages of constant power and constant bus voltage work modes. The new work mode is reasonable to keep the battery in good working conditions and to extend its life. Also the working conditions of engine can be bettered to get low pollution and high efficiency.展开更多
Wireless Sensor Network(WSN)is a cornerstone of Internet of Things(IoT)and has rich application scenarios.In this work,we consider a heterogeneous WSN whose sensor nodes have a diversity in their Residual Energy(RE).I...Wireless Sensor Network(WSN)is a cornerstone of Internet of Things(IoT)and has rich application scenarios.In this work,we consider a heterogeneous WSN whose sensor nodes have a diversity in their Residual Energy(RE).In this work,to protect the sensor nodes with low RE,we investigate dynamic working modes for sensor nodes which are determined by their RE and an introduced energy threshold.Besides,we employ an Unmanned Aerial Vehicle(UAV)to collect the stored data from the heterogeneous WSN.We aim to jointly optimize the cluster head selection,energy threshold and sensor nodes’working mode to minimize the weighted sum of energy con-sumption from the WSN and UAV,subject to the data collection rate constraint.To this end,we propose an efficient search method to search for an optimal energy threshold,and develop a penalty-based successive convex approximation algorithm to select the cluster heads.Then we present a low-complexity iterative approach to solve the joint optimization problem and discuss the implementation procedure.Numerical results justify that our proposed approach is able to reduce the energy consumption of the sensor nodes with low RE significantly and also saves energy for the whole WSN.展开更多
The paper analyzes the practical use of management mode of small-scale farmland irrigation works in China,and studies various problems existing in the present management mode.It puts forward a mode named Water-consume...The paper analyzes the practical use of management mode of small-scale farmland irrigation works in China,and studies various problems existing in the present management mode.It puts forward a mode named Water-consumer Association which is the most practical one at present.It points out some rules which must be mastered in solving problems appearing in using this mode.展开更多
Project-based learning has been in widespread use in education. However, project managers are unaware of the students’ lack of experience and treat them as if they were professional staff. This paper proposes the app...Project-based learning has been in widespread use in education. However, project managers are unaware of the students’ lack of experience and treat them as if they were professional staff. This paper proposes the application of a fuzzy failure mode and effects analysis model for project-based software engineering education. This method integrates the fuzzy rule-based system with learning agents. The agents construct the membership function from historical data. Data are processed by a clustering process that facilitates the construction of the membership function. It helps students who lack experience in risk assessment to develop their expertise in that skill. The paper also suggests a classification technique for a fuzzy rule-based system that can be used to judge risk based on a fuzzy inference system. The student project will thus be further enhanced with respect to risk assessment. We then discuss the design of experiments to verify the proposed model.展开更多
As a power infrastructure directly facing power users, transmission line is the direct power source of end users. Therefore, the normal operation of transmission line is a key link to ensure high-quality power supply ...As a power infrastructure directly facing power users, transmission line is the direct power source of end users. Therefore, the normal operation of transmission line is a key link to ensure high-quality power supply service. Due to the wide range of transmission line erection, the erection site is mainly in urban areas with complex environment, and the insulation level is lower than the transmission network, resulting in high failure rate, heavy maintenance workload and more power outages caused by maintenance. In order to ensure the reliability demand of users, improve the satisfaction of users, and reduce the power failure caused by maintenance and fault, live working technology is proposed and applied to practical production. Live working is a kind of operation mode for inspection and maintenance under the condition of keeping all equipment of power grid without power failure. At present, most of the maintenance work and accident handling work in the transmission line can be completed under the condition of live operation. Therefore, the implementation of live operation can significantly reduce the power outage duration and power outage times of users and improve the reliability of power supply.展开更多
In this paper, we put forward a collaborative mode based on A/S mode to solve existing problems in the process of developing electromechanical instrument collaborative sharing system (EICSS). The mode architecture, wo...In this paper, we put forward a collaborative mode based on A/S mode to solve existing problems in the process of developing electromechanical instrument collaborative sharing system (EICSS). The mode architecture, working pattern and development flow of this system were described. The prototype system developed was applied to Lambda 900 Spectrometer in Chongqing University to realize electromechanical instrument networked sharing, and demonstrated desirable expansibility and felxibility to satisfy diverse demands of customers.展开更多
IEEE has set up in October 2004 the IEEE802.22 Working Group—Wireless Regional Area Network(WRAN)Task Force to work out air interface standard based on Cognitive Radio(CR)technologies.The standard includes Physical L...IEEE has set up in October 2004 the IEEE802.22 Working Group—Wireless Regional Area Network(WRAN)Task Force to work out air interface standard based on Cognitive Radio(CR)technologies.The standard includes Physical Layer(PHY)and Media Access Control(MAC),to use the already allocated fallow spectrums to broadcast TV in a non-interference way.The WRAN employs CR technologies to sense and estimate the television frequencies and use the technologies of dynamic spectrum management to find and then allocate idle spectrums.The CR technologies are representing one of the major trends for future wireless communications.This article on WRANs and CR technologies will be divided into two issues.In this issue,WRANs and IEEE 802.22,CR technologies are introduced.And the second part in the next issue will analyze the applications of CR technologies.展开更多
Smooth switchover of micro-grid from parallel operation mode to island operation mode is a signif icant method to guarantee the continuous power supply to important loads.This paper puts forward an online work mode on...Smooth switchover of micro-grid from parallel operation mode to island operation mode is a signif icant method to guarantee the continuous power supply to important loads.This paper puts forward an online work mode on the basis of analyzing the features of parallel operation mode and island operation mode.According to the features of online work mode,the paper gives a f ixed and unf ixed DC bus voltage control strategy and builds the simulation model of unf ixed DC bus voltage control strategy based on Matlab/Simulink.The simulation results show that online work mode based on the unf ixed DC bus voltage control strategy can avoid the unstable problem caused by handoff process between parallel mode and island mode,ensure uninterrupted power supply for important loads,and achieve maximum power tracking of photovoltaic power generation,in addition to reducing the complexity and cost of the system.展开更多
World Data Center-D for Seismology(WDCDS)is a member of the World Data Center System under ICSU and is one of the nine World Data Centers located in China(WDC-D).During the period from 1993 to 1996,an information netw...World Data Center-D for Seismology(WDCDS)is a member of the World Data Center System under ICSU and is one of the nine World Data Centers located in China(WDC-D).During the period from 1993 to 1996,an information network system,called CSDInet,was developed in National Center for Seismic Data and Information(NCSDI)and has become the basic technical supporting system for WDC-D for Seismology.CSDInet consists of four basic parts:computer network center,LAN(Local Area Network),link to Internet,and nationwide PSTN(with dialing-up telephone line)user network.In this paper a "multi-layer multi-mode" management of data flow for this system will be explained and the data and information services will be described.展开更多
Objective: to explore the effect of fine management mode on efficiency, error rate and satisfaction of dispensing in outpatient pharmacy. Methods: 200 outpatients in our hospital from January 2019 to December 2019 wer...Objective: to explore the effect of fine management mode on efficiency, error rate and satisfaction of dispensing in outpatient pharmacy. Methods: 200 outpatients in our hospital from January 2019 to December 2019 were retrospectively analyzed and divided into conventional group and refined management group according to the implementation time of refined management mode of dispensing work in outpatient pharmacy. Among them, the conventional group adopted the routine management mode, while the refined management group adopted the refined management mode. The incidence of prescription dispensing errors, the time spent on prescription dispensing and the waiting time for patients to take medicine were compared, and the satisfaction of patients in the two groups was compared. Results: the incidence of prescription dispensing error, the time spent on prescription dispensing and waiting time for patients in the refined management group were significantly lower than those in the conventional group, and the satisfaction of patients was higher than that in the conventional group, P < 0.05. Conclusions: the refined management mode can reduce the incidence of prescription dispensing errors and improve satisfaction of patients, shorten the time spent in prescription dispensing and the waiting time for patients to take medicine.展开更多
The FY-2C meteorological satellite had been working well for 8 years as of October 19, 2012. Though the satellite was originally designed to work for 3 years, it still operates steadily. As the nation's first oper...The FY-2C meteorological satellite had been working well for 8 years as of October 19, 2012. Though the satellite was originally designed to work for 3 years, it still operates steadily. As the nation's first operational first-generation geo- stationary meteorological satellite, FY-2C works together with the following satellites FY-2D, FY-2E and FY-2F, in a operational mode of two operational plus two backup ones. FY-2C, FY-2D and FY-2E were the second batch satellites of FY-2 series展开更多
文摘A more accurate analysis method on working modes is proposed by considering the winding terminal voltage and the eondueting power device as state parameters. For the three-phase hybrid excitation doubly salient machine （HEDSM） motor and its three-phase full-bridge inverter, in the proposed analytical method, all possible working modes are generally listed. Then, with the H_PWM-L_ON control strategy, the working modes are detailed with eorresponding equivalent circuits. Experimental results verify the robustness of the analysis.
文摘From electric circuit theory view, a system model of series hybrid electric vehicle was built which uses engine-generator and battery pack as its on-board energy source in this paper. Based on the analysis for the constant power work mode and constant bus voltage work mode of engine-generator, a third work mode was put forward which combined the advantages of constant power and constant bus voltage work modes. The new work mode is reasonable to keep the battery in good working conditions and to extend its life. Also the working conditions of engine can be bettered to get low pollution and high efficiency.
基金supported in part by the National Nature Science Foundation of China under Grant 62001168in part by the Foundation and Application Research Grant of Guangzhou under Grant 202102020515.
文摘Wireless Sensor Network(WSN)is a cornerstone of Internet of Things(IoT)and has rich application scenarios.In this work,we consider a heterogeneous WSN whose sensor nodes have a diversity in their Residual Energy(RE).In this work,to protect the sensor nodes with low RE,we investigate dynamic working modes for sensor nodes which are determined by their RE and an introduced energy threshold.Besides,we employ an Unmanned Aerial Vehicle(UAV)to collect the stored data from the heterogeneous WSN.We aim to jointly optimize the cluster head selection,energy threshold and sensor nodes’working mode to minimize the weighted sum of energy con-sumption from the WSN and UAV,subject to the data collection rate constraint.To this end,we propose an efficient search method to search for an optimal energy threshold,and develop a penalty-based successive convex approximation algorithm to select the cluster heads.Then we present a low-complexity iterative approach to solve the joint optimization problem and discuss the implementation procedure.Numerical results justify that our proposed approach is able to reduce the energy consumption of the sensor nodes with low RE significantly and also saves energy for the whole WSN.
基金Supported by Provincial Water Conservancy Research and Technology Promotion Project:Research on Key Technical Problems of Farmland Water Conservancy Projects in Shandong Province(SDSLKY201401)
文摘The paper analyzes the practical use of management mode of small-scale farmland irrigation works in China,and studies various problems existing in the present management mode.It puts forward a mode named Water-consumer Association which is the most practical one at present.It points out some rules which must be mastered in solving problems appearing in using this mode.
文摘Project-based learning has been in widespread use in education. However, project managers are unaware of the students’ lack of experience and treat them as if they were professional staff. This paper proposes the application of a fuzzy failure mode and effects analysis model for project-based software engineering education. This method integrates the fuzzy rule-based system with learning agents. The agents construct the membership function from historical data. Data are processed by a clustering process that facilitates the construction of the membership function. It helps students who lack experience in risk assessment to develop their expertise in that skill. The paper also suggests a classification technique for a fuzzy rule-based system that can be used to judge risk based on a fuzzy inference system. The student project will thus be further enhanced with respect to risk assessment. We then discuss the design of experiments to verify the proposed model.
文摘As a power infrastructure directly facing power users, transmission line is the direct power source of end users. Therefore, the normal operation of transmission line is a key link to ensure high-quality power supply service. Due to the wide range of transmission line erection, the erection site is mainly in urban areas with complex environment, and the insulation level is lower than the transmission network, resulting in high failure rate, heavy maintenance workload and more power outages caused by maintenance. In order to ensure the reliability demand of users, improve the satisfaction of users, and reduce the power failure caused by maintenance and fault, live working technology is proposed and applied to practical production. Live working is a kind of operation mode for inspection and maintenance under the condition of keeping all equipment of power grid without power failure. At present, most of the maintenance work and accident handling work in the transmission line can be completed under the condition of live operation. Therefore, the implementation of live operation can significantly reduce the power outage duration and power outage times of users and improve the reliability of power supply.
基金Funded by the Foundation for 211 Projects of the Ministry of Education During the 10th Five-year Plan Period of China (No. shi wu 211CERS-13).
文摘In this paper, we put forward a collaborative mode based on A/S mode to solve existing problems in the process of developing electromechanical instrument collaborative sharing system (EICSS). The mode architecture, working pattern and development flow of this system were described. The prototype system developed was applied to Lambda 900 Spectrometer in Chongqing University to realize electromechanical instrument networked sharing, and demonstrated desirable expansibility and felxibility to satisfy diverse demands of customers.
文摘IEEE has set up in October 2004 the IEEE802.22 Working Group—Wireless Regional Area Network(WRAN)Task Force to work out air interface standard based on Cognitive Radio(CR)technologies.The standard includes Physical Layer(PHY)and Media Access Control(MAC),to use the already allocated fallow spectrums to broadcast TV in a non-interference way.The WRAN employs CR technologies to sense and estimate the television frequencies and use the technologies of dynamic spectrum management to find and then allocate idle spectrums.The CR technologies are representing one of the major trends for future wireless communications.This article on WRANs and CR technologies will be divided into two issues.In this issue,WRANs and IEEE 802.22,CR technologies are introduced.And the second part in the next issue will analyze the applications of CR technologies.
基金Project Supported by the National High Technology Research and Development of China 863 Program(2012AA050214)the National Natural Science Foundation of China(51207047)the Science and Technology Project in Changzhou(CM20123009)
文摘Smooth switchover of micro-grid from parallel operation mode to island operation mode is a signif icant method to guarantee the continuous power supply to important loads.This paper puts forward an online work mode on the basis of analyzing the features of parallel operation mode and island operation mode.According to the features of online work mode,the paper gives a f ixed and unf ixed DC bus voltage control strategy and builds the simulation model of unf ixed DC bus voltage control strategy based on Matlab/Simulink.The simulation results show that online work mode based on the unf ixed DC bus voltage control strategy can avoid the unstable problem caused by handoff process between parallel mode and island mode,ensure uninterrupted power supply for important loads,and achieve maximum power tracking of photovoltaic power generation,in addition to reducing the complexity and cost of the system.
文摘World Data Center-D for Seismology(WDCDS)is a member of the World Data Center System under ICSU and is one of the nine World Data Centers located in China(WDC-D).During the period from 1993 to 1996,an information network system,called CSDInet,was developed in National Center for Seismic Data and Information(NCSDI)and has become the basic technical supporting system for WDC-D for Seismology.CSDInet consists of four basic parts:computer network center,LAN(Local Area Network),link to Internet,and nationwide PSTN(with dialing-up telephone line)user network.In this paper a "multi-layer multi-mode" management of data flow for this system will be explained and the data and information services will be described.
文摘Objective: to explore the effect of fine management mode on efficiency, error rate and satisfaction of dispensing in outpatient pharmacy. Methods: 200 outpatients in our hospital from January 2019 to December 2019 were retrospectively analyzed and divided into conventional group and refined management group according to the implementation time of refined management mode of dispensing work in outpatient pharmacy. Among them, the conventional group adopted the routine management mode, while the refined management group adopted the refined management mode. The incidence of prescription dispensing errors, the time spent on prescription dispensing and the waiting time for patients to take medicine were compared, and the satisfaction of patients in the two groups was compared. Results: the incidence of prescription dispensing error, the time spent on prescription dispensing and waiting time for patients in the refined management group were significantly lower than those in the conventional group, and the satisfaction of patients was higher than that in the conventional group, P < 0.05. Conclusions: the refined management mode can reduce the incidence of prescription dispensing errors and improve satisfaction of patients, shorten the time spent in prescription dispensing and the waiting time for patients to take medicine.
文摘The FY-2C meteorological satellite had been working well for 8 years as of October 19, 2012. Though the satellite was originally designed to work for 3 years, it still operates steadily. As the nation's first operational first-generation geo- stationary meteorological satellite, FY-2C works together with the following satellites FY-2D, FY-2E and FY-2F, in a operational mode of two operational plus two backup ones. FY-2C, FY-2D and FY-2E were the second batch satellites of FY-2 series
