We study preconditioning techniques used in conjunction with the conjugate gradient method for solving multi-length-scale symmetric positive definite linear systems originating from the quantum Monte Carlo simulation ...We study preconditioning techniques used in conjunction with the conjugate gradient method for solving multi-length-scale symmetric positive definite linear systems originating from the quantum Monte Carlo simulation of electron interaction of correlated materials. Existing preconditioning techniques are not designed to be adaptive to varying numerical properties of the multi-length-scale systems. In this paper, we propose a hybrid incomplete Cholesky （HIC） preconditioner and demonstrate its adaptivity to the multi-length-scale systems. In addition, we propose an extension of the compressed sparse column with row access （CSCR） sparse matrix storage format to efficiently accommodate the data access pattem to compute the HIC preconditioner. We show that for moderately correlated materials, the HIC preconditioner achieves the optimal linear scaling of the simulation. The development of a linear-scaling preconditioner for strongly correlated materials remains an open topic.展开更多
The modeling of a ship steering integrated simulator(SSIS)applied to the design,debugging and maintenance of an autopilot is discussed.A nonlinear responsive model is proposed and applied to the design of SSIS.The SSI...The modeling of a ship steering integrated simulator(SSIS)applied to the design,debugging and maintenance of an autopilot is discussed.A nonlinear responsive model is proposed and applied to the design of SSIS.The SSIS generates real signals of the ship heading,the rudder angle,the ship position and the output to the autopilot.A variety of factors,such as ship speed variety,shallow water effect,nonlinearity of yaw and actuator,and environmental disturbances like wind,wave and current are considered carefully.Detailed formulas for calculating relevant parameters are provided.Taken a naval ship as an example,the physical-digital simulations on SSIS and the digital simulation on a Marine System Simulator(MSS)were conducted separately in various sailing conditions.Simulation results show that the simple nonlinear responsive model can be applied to ship motion control and simulation with sufficient accuracy and effectiveness.展开更多
Weeds normally grow in patches and spatially distributed in field. Patch spraying to control weeds has advantages of chemical saving, reduced cost and environmental pollution. Advent of electro-optical sensing capabil...Weeds normally grow in patches and spatially distributed in field. Patch spraying to control weeds has advantages of chemical saving, reduced cost and environmental pollution. Advent of electro-optical sensing capabilities has paved the way of using machine vision technologies for patch spraying. Machine vision system has to acquire and process digital images to make control decisions. Proper identification and classification of objects present in image holds the key to make control decisions and use of any spraying operation performed. Recognition of objects in digital image may be affected by background, intensity, image resolution, orientation of the object and geometrical characteristics. A set of 16, including 11 shape and 5 texture-based parameters coupled with predictive discriminating analysis has been used to identify the weed leaves. Geometrical features were indexed successfully to eliminate the effect of object orientation. Linear discriminating analysis was found to be more effective in correct classification of weed leaves. The classification accuracy of 69% to 80% was observed. These features can be utilized for development of image based variable rate sprayer.展开更多
In order to improve the accuracy of spoken English translation evaluation and artificial intelligence, the design of wireless mobile terminal lest of spoken English translation accuracy evaluation system is researched...In order to improve the accuracy of spoken English translation evaluation and artificial intelligence, the design of wireless mobile terminal lest of spoken English translation accuracy evaluation system is researched. The system uses four layer construction design as wireless information collection layer, the mobile terminal information fusion layer, network data transmission layer, human computer interactive application layer. The original collection of computer-based spoken English translation information is taken based on host computer communication sensing information processing technology, Bus data transmission of English translation accuracy evaluation system is taken based on B/S structure, the test design process and remote scheduling information fusion are constructed based on LabWindows/CVl and B/S structure mining system, information data processing and cross compiler operation of the spoken English translation test evaluation system are completed in application layer, in the embedded kernel and on the wireless mobile terminal, the evaluation system is developed. The test results show that the integrated scheduling ability of spoken English translation test information system designed in this paper is better than traditional method, the cost time is less, and the control quality of the system is high.展开更多
基金supported in part by the US National Science Foundation grant 0611548in part by the US Department of Energy grant DE-FC02-06ER25793
文摘We study preconditioning techniques used in conjunction with the conjugate gradient method for solving multi-length-scale symmetric positive definite linear systems originating from the quantum Monte Carlo simulation of electron interaction of correlated materials. Existing preconditioning techniques are not designed to be adaptive to varying numerical properties of the multi-length-scale systems. In this paper, we propose a hybrid incomplete Cholesky （HIC） preconditioner and demonstrate its adaptivity to the multi-length-scale systems. In addition, we propose an extension of the compressed sparse column with row access （CSCR） sparse matrix storage format to efficiently accommodate the data access pattem to compute the HIC preconditioner. We show that for moderately correlated materials, the HIC preconditioner achieves the optimal linear scaling of the simulation. The development of a linear-scaling preconditioner for strongly correlated materials remains an open topic.
文摘The modeling of a ship steering integrated simulator(SSIS)applied to the design,debugging and maintenance of an autopilot is discussed.A nonlinear responsive model is proposed and applied to the design of SSIS.The SSIS generates real signals of the ship heading,the rudder angle,the ship position and the output to the autopilot.A variety of factors,such as ship speed variety,shallow water effect,nonlinearity of yaw and actuator,and environmental disturbances like wind,wave and current are considered carefully.Detailed formulas for calculating relevant parameters are provided.Taken a naval ship as an example,the physical-digital simulations on SSIS and the digital simulation on a Marine System Simulator(MSS)were conducted separately in various sailing conditions.Simulation results show that the simple nonlinear responsive model can be applied to ship motion control and simulation with sufficient accuracy and effectiveness.
文摘Weeds normally grow in patches and spatially distributed in field. Patch spraying to control weeds has advantages of chemical saving, reduced cost and environmental pollution. Advent of electro-optical sensing capabilities has paved the way of using machine vision technologies for patch spraying. Machine vision system has to acquire and process digital images to make control decisions. Proper identification and classification of objects present in image holds the key to make control decisions and use of any spraying operation performed. Recognition of objects in digital image may be affected by background, intensity, image resolution, orientation of the object and geometrical characteristics. A set of 16, including 11 shape and 5 texture-based parameters coupled with predictive discriminating analysis has been used to identify the weed leaves. Geometrical features were indexed successfully to eliminate the effect of object orientation. Linear discriminating analysis was found to be more effective in correct classification of weed leaves. The classification accuracy of 69% to 80% was observed. These features can be utilized for development of image based variable rate sprayer.
文摘In order to improve the accuracy of spoken English translation evaluation and artificial intelligence, the design of wireless mobile terminal lest of spoken English translation accuracy evaluation system is researched. The system uses four layer construction design as wireless information collection layer, the mobile terminal information fusion layer, network data transmission layer, human computer interactive application layer. The original collection of computer-based spoken English translation information is taken based on host computer communication sensing information processing technology, Bus data transmission of English translation accuracy evaluation system is taken based on B/S structure, the test design process and remote scheduling information fusion are constructed based on LabWindows/CVl and B/S structure mining system, information data processing and cross compiler operation of the spoken English translation test evaluation system are completed in application layer, in the embedded kernel and on the wireless mobile terminal, the evaluation system is developed. The test results show that the integrated scheduling ability of spoken English translation test information system designed in this paper is better than traditional method, the cost time is less, and the control quality of the system is high.
