This paper proposed a new scheme for smooth handoff over F-HMIPv6 networks based on Location Based Services(LBS). It uses the available information about mobile node(MN) such as user mobility patterns and MN's vel...This paper proposed a new scheme for smooth handoff over F-HMIPv6 networks based on Location Based Services(LBS). It uses the available information about mobile node(MN) such as user mobility patterns and MN's velocity to reduce handoff latency. In the proposed scheme, the movement pattern of users plays an important role in the performance analysis. The proposed scheme develops LBS that records a number of mobility patterns based on user daily behavior, and exploits these information to reduce the handoff latency. The proposed scheme is analyzed and compared with F-HMIPv6 protocol. The results show that it improves the performance in terms of handoff latency, packet delivery cost, and location update cost. Specifically, the proposed scheme achieves the tradeoff between realizing a smooth handoff and minimizing the cost that is the demand for all customers of mobile services.展开更多
On the basis of analysing traditional motor ignitor,a new motor ignitor design with precise ignition angle control,consistency and low cost is proposed. Techniques of low pertinence to process and power supply are int...On the basis of analysing traditional motor ignitor,a new motor ignitor design with precise ignition angle control,consistency and low cost is proposed. Techniques of low pertinence to process and power supply are introduced to promote its stability,reliability and unity. This circuit is implemented with a standard CMOS technology with perfect electric static discharge(ESD) design and can work under a broad range of power supply from 3 V^5 V with a quiescent current less than 2 mA and can be widely used in motor with a displacement of 125 ml and below.展开更多
To meet the increasing research demand for deep space exploration,especially for the second libration point (L2) conditional periodic orbit (Halo orbit) in the Sun-Earth system,the methods to get analytical Halo orbit...To meet the increasing research demand for deep space exploration,especially for the second libration point (L2) conditional periodic orbit (Halo orbit) in the Sun-Earth system,the methods to get analytical Halo orbit and differential-correction Halo orbit were described firstly,and the corresponding orbits accuracy was analyzed.Then,based on the results of third-order and differential-correction Halo orbits,the formation form was studied.Analysis was carried out to discuss the influence of system amplitude,initial phase,and phase difference on the formation form,as well as that of initial orbit values on form accuracy.Finally,some simulation results demonstrate the validity of the proposed methods.展开更多
Human resources are the core of business development, the competition of modem enterprises, in the final analysis is the talent competition, which is the human development level of competition. Scenic spot enterprise ...Human resources are the core of business development, the competition of modem enterprises, in the final analysis is the talent competition, which is the human development level of competition. Scenic spot enterprise view service quality as their development lifeline, rely entirely on high-quality staff to achieve, tourist attractions enterprise has its particularity industry: labor-intensive enterprises, but different from other manufacturing and other labor-intensive enterprises, They have high quality requirements for comprehensive employee quality, and therefore human resource development, compared with other enterprises, is more important and more challenging.展开更多
This paper deals with the application of two different injection strategies in a natural gas direct injection spark ignition single-cylinder engine model. The analysis includes the air flow characterization during com...This paper deals with the application of two different injection strategies in a natural gas direct injection spark ignition single-cylinder engine model. The analysis includes the air flow characterization during compression stroke and also the charge stratification. Two different swirl ratios are applied and piston bowl effects are analyzed during the gas jet deflection towards the spark plug. Achieving wall-guided effect, consequently, the charge stratification in spark plug region is obtained. The goal is to study the mixture formation differences for a single and a bi pulsed CNG (compressed natural gas) injection profiles and check the evolution of the methane concentration at the spark plug at the start of combustion.展开更多
The paper presents the results of the experimental research which was carried out on the spark ignition engine, experimental model, fuelled with hydrogen by direct injection method, using qualitative load adjustment m...The paper presents the results of the experimental research which was carried out on the spark ignition engine, experimental model, fuelled with hydrogen by direct injection method, using qualitative load adjustment method for engine running control. Also, the hydrogen injection solution at the beginning of the compression stroke, after the inlet valve closing, assures the cylinder cooling by inlet air avoiding in that way uncontrolled ignition phenomena and inlet back fire. Using this fueling method avoided the abnormally hydrogen combustion phenomena's for stoichiometric dosage operating conditions, achieving -30 % engine power increase. Hydrogen engine runs with very lean mixtures, due to engine load qualitative adjustment, a dosage value that leads to a reduction of the engine power with -25% from maximum power value. This provides a higher engine efficiency at low loads, the best results was obtained for λ=2- 4 air-fuel ratio values. The influence of the mixture quality on burning process, on polluting and energetically engine performances at the fuelling with hydrogen using direct injection method are presented. Because of the higher combustion temperature, the NOx emission level is higher for λ=1 - 2 comparative to gasoline fuelled engine, but decreases a lot for leaner mixture values, λ〉2.5.展开更多
A method for spacecraft formation flying (SFF) design and control near libration point orbits was developed by making use of the Floquet theory for periodic orbits. Firstly, the Floquet theory used in libration point ...A method for spacecraft formation flying (SFF) design and control near libration point orbits was developed by making use of the Floquet theory for periodic orbits. Firstly, the Floquet theory used in libration point orbits was introduced and the coefficients of four Floquet periodic modes were proved to be nearly constant when the amplitude in z direction of earth-moon L1 halo orbits is less than 20000 km. On this basis, a configuration design approach to SFF in L1 halo orbits was proposed, and several types of special configurations were obtained with periodic mode 3 and mode 5 or mode 4 and mode 6. Then, in order to control the SFF configuration concisely, those coefficients of the 5 modes (except the stable one) must be kept constant. A stationkeeping method for SFF was developed, which controls 5 Floquet modes simultaneously. Finally, simulations showed that the Floquet-based approach of configuration design and control for SFF is effective, simple and convenient. The research may be of value for deep space explorations.展开更多
文摘This paper proposed a new scheme for smooth handoff over F-HMIPv6 networks based on Location Based Services(LBS). It uses the available information about mobile node(MN) such as user mobility patterns and MN's velocity to reduce handoff latency. In the proposed scheme, the movement pattern of users plays an important role in the performance analysis. The proposed scheme develops LBS that records a number of mobility patterns based on user daily behavior, and exploits these information to reduce the handoff latency. The proposed scheme is analyzed and compared with F-HMIPv6 protocol. The results show that it improves the performance in terms of handoff latency, packet delivery cost, and location update cost. Specifically, the proposed scheme achieves the tradeoff between realizing a smooth handoff and minimizing the cost that is the demand for all customers of mobile services.
文摘On the basis of analysing traditional motor ignitor,a new motor ignitor design with precise ignition angle control,consistency and low cost is proposed. Techniques of low pertinence to process and power supply are introduced to promote its stability,reliability and unity. This circuit is implemented with a standard CMOS technology with perfect electric static discharge(ESD) design and can work under a broad range of power supply from 3 V^5 V with a quiescent current less than 2 mA and can be widely used in motor with a displacement of 125 ml and below.
文摘To meet the increasing research demand for deep space exploration,especially for the second libration point (L2) conditional periodic orbit (Halo orbit) in the Sun-Earth system,the methods to get analytical Halo orbit and differential-correction Halo orbit were described firstly,and the corresponding orbits accuracy was analyzed.Then,based on the results of third-order and differential-correction Halo orbits,the formation form was studied.Analysis was carried out to discuss the influence of system amplitude,initial phase,and phase difference on the formation form,as well as that of initial orbit values on form accuracy.Finally,some simulation results demonstrate the validity of the proposed methods.
文摘Human resources are the core of business development, the competition of modem enterprises, in the final analysis is the talent competition, which is the human development level of competition. Scenic spot enterprise view service quality as their development lifeline, rely entirely on high-quality staff to achieve, tourist attractions enterprise has its particularity industry: labor-intensive enterprises, but different from other manufacturing and other labor-intensive enterprises, They have high quality requirements for comprehensive employee quality, and therefore human resource development, compared with other enterprises, is more important and more challenging.
文摘This paper deals with the application of two different injection strategies in a natural gas direct injection spark ignition single-cylinder engine model. The analysis includes the air flow characterization during compression stroke and also the charge stratification. Two different swirl ratios are applied and piston bowl effects are analyzed during the gas jet deflection towards the spark plug. Achieving wall-guided effect, consequently, the charge stratification in spark plug region is obtained. The goal is to study the mixture formation differences for a single and a bi pulsed CNG (compressed natural gas) injection profiles and check the evolution of the methane concentration at the spark plug at the start of combustion.
文摘The paper presents the results of the experimental research which was carried out on the spark ignition engine, experimental model, fuelled with hydrogen by direct injection method, using qualitative load adjustment method for engine running control. Also, the hydrogen injection solution at the beginning of the compression stroke, after the inlet valve closing, assures the cylinder cooling by inlet air avoiding in that way uncontrolled ignition phenomena and inlet back fire. Using this fueling method avoided the abnormally hydrogen combustion phenomena's for stoichiometric dosage operating conditions, achieving -30 % engine power increase. Hydrogen engine runs with very lean mixtures, due to engine load qualitative adjustment, a dosage value that leads to a reduction of the engine power with -25% from maximum power value. This provides a higher engine efficiency at low loads, the best results was obtained for λ=2- 4 air-fuel ratio values. The influence of the mixture quality on burning process, on polluting and energetically engine performances at the fuelling with hydrogen using direct injection method are presented. Because of the higher combustion temperature, the NOx emission level is higher for λ=1 - 2 comparative to gasoline fuelled engine, but decreases a lot for leaner mixture values, λ〉2.5.
基金supported by the National Natural Science Foundation of China (Grant No. 10702078)the National University of Defense Technology Research Program (Grant No. JC08-01-05)
文摘A method for spacecraft formation flying (SFF) design and control near libration point orbits was developed by making use of the Floquet theory for periodic orbits. Firstly, the Floquet theory used in libration point orbits was introduced and the coefficients of four Floquet periodic modes were proved to be nearly constant when the amplitude in z direction of earth-moon L1 halo orbits is less than 20000 km. On this basis, a configuration design approach to SFF in L1 halo orbits was proposed, and several types of special configurations were obtained with periodic mode 3 and mode 5 or mode 4 and mode 6. Then, in order to control the SFF configuration concisely, those coefficients of the 5 modes (except the stable one) must be kept constant. A stationkeeping method for SFF was developed, which controls 5 Floquet modes simultaneously. Finally, simulations showed that the Floquet-based approach of configuration design and control for SFF is effective, simple and convenient. The research may be of value for deep space explorations.