Aim To present an ASIC design of DA based 2 D IDCT. Methods\ In the design of 1 D IDCT is utilized a Chen based fast IDCT algorithm, and multiplier accumulators based on distributed algorithm contributes in reduc...Aim To present an ASIC design of DA based 2 D IDCT. Methods\ In the design of 1 D IDCT is utilized a Chen based fast IDCT algorithm, and multiplier accumulators based on distributed algorithm contributes in reducing the hardware amount and in enhancing the speed performance. Results and Conclusion\ VHDL simulation, synthesis and layout design of system are implemented. This 2 D IDCT ASIC design owns best timing performance when compared with other better designs internationally. Results of design prove to be excellent.展开更多
In order to realize the computer aided design of AT shifting element schemes, a mathematical model of shifting element schemes which can be easily identified by computers was built. Taking the transmission ratio seque...In order to realize the computer aided design of AT shifting element schemes, a mathematical model of shifting element schemes which can be easily identified by computers was built. Taking the transmission ratio sequence as an optimization objective and simple shifting logic between adjacent gears through operating only one shifting element as a constraint condition, a fitness function of shifting element schemes was proposed. ZF-8AT shifting element schemes were optimized based on GA work-box of MATLAB, and the feasibility of the optimization algorithm was verified.展开更多
Rigorous modeling could improve the correctness and reduce cost in embedded real-time system development for models could be verified. Tools are needed for rigorous modeling of embedded real-time system. UML is an ind...Rigorous modeling could improve the correctness and reduce cost in embedded real-time system development for models could be verified. Tools are needed for rigorous modeling of embedded real-time system. UML is an industrial standard modeling language which provides a powerful expressi-veness, intuitive and easy to use interface to model. UML is widely accepted by software developer. However, for lack of precisely defined semantics, especially on the dynamic diagrams, UML model is hard to be verified. PVS is a general formal method which provides a high-order logic specification language and integrated with model checking and theorem proving tools. Combining the widely used UML with PVS, this paper provides a novel modeling and verification approach for embedded real-time system. In this approach, we provide 1) a timed extended UML statechart for modeling dynamic behavior of an embedded real-time system; 2) an approach to capture timed automata based semantics from timed statechart; and 3) an algorithm to generate a finite state model expressed in PVS specification for model checking. The benefits of our approach include flexible and friendly in modeling, extendable in forma-lization and verification content, and better performance. Time constraints are modeled and verified and it’s a highlight of this paper.展开更多
Aiming at the assembly accuracy of a large aircraft transport jig, the effect of component error and the error of work-piece surface on the work-piece position and orientation in the 3-2-1 fixturing scheme is studied ...Aiming at the assembly accuracy of a large aircraft transport jig, the effect of component error and the error of work-piece surface on the work-piece position and orientation in the 3-2-1 fixturing scheme is studied with the object pose space description method. The error mapping model between the connecting part of the front frame rack and its support base is modeled using the homogeneous transformation matrix(HTM) method. The probabilistic error is simulated using the Monte Carlo method. The measurement experiment was conducted by the laser tracker to verify the effectiveness of the approach, and the approach has been successfully applied to the production of transport jig.展开更多
The three-dimensional inverse transient thermoelastic problem for a thin rectangular object is considered within the context of the theory of generalized thermoelasticity. The upper surface of the rectangular object o...The three-dimensional inverse transient thermoelastic problem for a thin rectangular object is considered within the context of the theory of generalized thermoelasticity. The upper surface of the rectangular object occupying the space D： -a〈xSa; -b〈_y〈b; 0〈z〈h; with the known boundary conditions. Laplace and Finite Marchi-Fasulo transform techniques are used to determine the unknown temperature, temperature distribution, displacement and thermal stresses on upper plane surface of a thin rectangular object. The distributions of the considered physical variables are obtained and represented graphically.展开更多
An all-fiber LP_(01)-LP_(11) mode convertor based on side-polished small-core single-mode fibers(SMFs) is numerically demonstrated. The linearly polarized incident beam in one arm experiences π shift through a fiber ...An all-fiber LP_(01)-LP_(11) mode convertor based on side-polished small-core single-mode fibers(SMFs) is numerically demonstrated. The linearly polarized incident beam in one arm experiences π shift through a fiber half waveplate, and the side-polished parts merge into an equivalent twin-core fiber(TCF) which spatially shapes the incident LP_(01) modes to the LP_(11) mode supported by the step-index few-mode fiber(FMF). Optimum conditions for the highest conversion efficiency are investigated using the beam propagation method(BPM) with an approximate efficiency as high as 96.7%. The proposed scheme can operate within a wide wavelength range from 1.3 μm to1.7 μm with overall conversion efficiency greater than 95%. The effective mode area and coupling loss are also characterized in detail by finite element method(FEM).展开更多
文摘Aim To present an ASIC design of DA based 2 D IDCT. Methods\ In the design of 1 D IDCT is utilized a Chen based fast IDCT algorithm, and multiplier accumulators based on distributed algorithm contributes in reducing the hardware amount and in enhancing the speed performance. Results and Conclusion\ VHDL simulation, synthesis and layout design of system are implemented. This 2 D IDCT ASIC design owns best timing performance when compared with other better designs internationally. Results of design prove to be excellent.
基金Project(2011BAG09B00)supported by the National Science and Technology Support Program,China
文摘In order to realize the computer aided design of AT shifting element schemes, a mathematical model of shifting element schemes which can be easily identified by computers was built. Taking the transmission ratio sequence as an optimization objective and simple shifting logic between adjacent gears through operating only one shifting element as a constraint condition, a fitness function of shifting element schemes was proposed. ZF-8AT shifting element schemes were optimized based on GA work-box of MATLAB, and the feasibility of the optimization algorithm was verified.
文摘Rigorous modeling could improve the correctness and reduce cost in embedded real-time system development for models could be verified. Tools are needed for rigorous modeling of embedded real-time system. UML is an industrial standard modeling language which provides a powerful expressi-veness, intuitive and easy to use interface to model. UML is widely accepted by software developer. However, for lack of precisely defined semantics, especially on the dynamic diagrams, UML model is hard to be verified. PVS is a general formal method which provides a high-order logic specification language and integrated with model checking and theorem proving tools. Combining the widely used UML with PVS, this paper provides a novel modeling and verification approach for embedded real-time system. In this approach, we provide 1) a timed extended UML statechart for modeling dynamic behavior of an embedded real-time system; 2) an approach to capture timed automata based semantics from timed statechart; and 3) an algorithm to generate a finite state model expressed in PVS specification for model checking. The benefits of our approach include flexible and friendly in modeling, extendable in forma-lization and verification content, and better performance. Time constraints are modeled and verified and it’s a highlight of this paper.
基金Supported by National Key Technology Research and Development Program of China(No.2012BAF01B07)
文摘Aiming at the assembly accuracy of a large aircraft transport jig, the effect of component error and the error of work-piece surface on the work-piece position and orientation in the 3-2-1 fixturing scheme is studied with the object pose space description method. The error mapping model between the connecting part of the front frame rack and its support base is modeled using the homogeneous transformation matrix(HTM) method. The probabilistic error is simulated using the Monte Carlo method. The measurement experiment was conducted by the laser tracker to verify the effectiveness of the approach, and the approach has been successfully applied to the production of transport jig.
基金University Grant Commission,New Delhi for providing the partial financial assistance under major research project scheme
文摘The three-dimensional inverse transient thermoelastic problem for a thin rectangular object is considered within the context of the theory of generalized thermoelasticity. The upper surface of the rectangular object occupying the space D： -a〈xSa; -b〈_y〈b; 0〈z〈h; with the known boundary conditions. Laplace and Finite Marchi-Fasulo transform techniques are used to determine the unknown temperature, temperature distribution, displacement and thermal stresses on upper plane surface of a thin rectangular object. The distributions of the considered physical variables are obtained and represented graphically.
基金supported by the Fundamental Research Funds for the Central Universities(No.2016JBM002)
文摘An all-fiber LP_(01)-LP_(11) mode convertor based on side-polished small-core single-mode fibers(SMFs) is numerically demonstrated. The linearly polarized incident beam in one arm experiences π shift through a fiber half waveplate, and the side-polished parts merge into an equivalent twin-core fiber(TCF) which spatially shapes the incident LP_(01) modes to the LP_(11) mode supported by the step-index few-mode fiber(FMF). Optimum conditions for the highest conversion efficiency are investigated using the beam propagation method(BPM) with an approximate efficiency as high as 96.7%. The proposed scheme can operate within a wide wavelength range from 1.3 μm to1.7 μm with overall conversion efficiency greater than 95%. The effective mode area and coupling loss are also characterized in detail by finite element method(FEM).
