This paper advances a new algorithm oriented to geometry modeling (GM) by using frame model. The elemental data structure of frame model is the vertex. This afeoithm provides a general and rapid method. By this way,we...This paper advances a new algorithm oriented to geometry modeling (GM) by using frame model. The elemental data structure of frame model is the vertex. This afeoithm provides a general and rapid method. By this way,we can link the vertices to construct the elemental frame and need not consider the topological relation among vertices which consist of the concrete entity. Then, we can combine the elemental frames to complete frame modeling by using aided-line method referring to concrete entity. We will discuss two keystones in the paper. Then we give a 3D geometry modeling example based on wire-frame model using the new algorithm.展开更多
By means of analogy, this paper analyses the present functional hierarchyframe model for system maintainability, and presents an improved model. Practical applicationindicates that the improved model is visualized, mo...By means of analogy, this paper analyses the present functional hierarchyframe model for system maintainability, and presents an improved model. Practical applicationindicates that the improved model is visualized, more convenient and perfected over the perviousmodels.展开更多
This paper presents a method for unsupervised segmentation of images consisting of multiple textures. The images under study are modeled by a proposed hierarchical random field model, which has two layers. The first l...This paper presents a method for unsupervised segmentation of images consisting of multiple textures. The images under study are modeled by a proposed hierarchical random field model, which has two layers. The first layer is modeled as a Markov Random Field (MRF) representing an unobservable region image and the second layer uses 'Filters, Random and Maximum Entropy (Abb. FRAME)' model to represent multiple textures which cover each region. Compared with the traditional Hierarchical Markov Random Field (HMRF), the FRAME can use a bigger neighborhood system and model more complex patterns. The segmentation problem is formulated as Maximum a Posteriori (MAP) estimation according to the Bayesian rule. The iterated conditional modes (ICM) algorithm is carried out to find the solution of the MAP estimation. An algorithm based on the local entropy rate is proposed to simplify the estimation of the parameters of MRF. The parameters of FRAME are estimated by the ExpectationMaximum (EM) algorithm. Finally, an experiment with synthesized and real images is given, which shows that the method can segment images with complex textures efficiently and is robust to noise.展开更多
Isothermal flashless die forging process of Ti - alloy structural air - frame part with varying thickness rib has been modelled in this paper.The results of present study show that a upside - down trapezoid rib would...Isothermal flashless die forging process of Ti - alloy structural air - frame part with varying thickness rib has been modelled in this paper.The results of present study show that a upside - down trapezoid rib would be formed and buckling would occure as blank is reduced,if the thickness of billet is maller than or equal to the thickness of rib. During modelling process of structural air frame part with E type cross - section rib, the saddle or lap would be formed finally at the middle of transverse rib between ribs with increase in deformation.If metal is allowed to flow out at confluence of longitudinal and transverse rib, the lop defect would be eliminated,, but a pipe cavity is obvious on corresponding loca- tion of blank. of defect formation depends on distance of metal flow ,friction,temperature homoge- neity of the blank and complexity of the part.展开更多
A “LAG & RLC” visualization algorithm has been presented to display a clear three dimensional structure from stereo slice data which has the characteristics of multiple layer structure. This algorithm is based o...A “LAG & RLC” visualization algorithm has been presented to display a clear three dimensional structure from stereo slice data which has the characteristics of multiple layer structure. This algorithm is based on wire frame model which can do multiple logical operations and has multiple display effects. It has wide use in biomedical science and computer graphics. The practical system is based on PC with a TVGA adapter at least 512k byte display memory and 2M byte extended memory.展开更多
The fishbone model is a simplified numerical model for moment-resisting frames that is capable of modelling the effects of column-beam strength and stiffness ratios. The applicability of the fishbone model in simulati...The fishbone model is a simplified numerical model for moment-resisting frames that is capable of modelling the effects of column-beam strength and stiffness ratios. The applicability of the fishbone model in simulating the seismic responses of reinforced concrete moment-resisting frames of different sets of column-beam strength and stiffness ratios are evaluated through nonlinear static, dynamic and incremental dynamic analysis on six prototype buildings of 4-, 8-and 12-stories. The results show that the fishbone model is practically accurate enough for reinforced concrete frames, although the assumption of equal joint rotation does not hold in all cases. In addition to the ground motion characteristics and the number of stories in the structures, the accuracy of the model also varies with the column-beam stiffness and strength ratios. The model performs better for strong column-weak beam frames, in which the lateral drift patterns are better controlled by the continuous stiffness provided by the strong columns. When the inelastic deformation is large, the accuracy of the model may be subjected to large record-to-record variability. This is especially the case for frames of weak columns.展开更多
This paper presents an option for modern dynamic terrestrial reference system realization in Uzbekistan for user needs. An additive model is explored to predict patterns of time series and investigate means of constru...This paper presents an option for modern dynamic terrestrial reference system realization in Uzbekistan for user needs. An additive model is explored to predict patterns of time series and investigate means of constructing forecast time series models in the future. The main components(trend, periodical, and irregular) of the KIUB(DORIS) and KIT3, TASH, MADK, and MTAL(GNSS) international stations coordinate time series were investigated. It was shown that seasonal nonlinear trends occurred both in the height(U) component of all stations and the east(E) component of high mountainous stations such as MTAL and MADK. The seasonal periodical portion of the time series determined from the additive model has a complicated pattern for all sites and can be explained as both hydrological signals in the region and improvement of observational quality. Amplitudes of the best-fitting sinusoids in the North component ranged between 1.73 and 8.76 mm; the East component ranged between 0.82 and 11.92 mm; and the Up component ranged between 3.11 and 40.81 mm. Regression analysis of the irregular portion of the height component of the two techniques at the Kitab station using tropospheric parameters(pressure and temperature) was confirmed as only 57% of the stochastic portion of the time series.展开更多
We investigate the role of extended intrinsic mean spin tensor introduced in this work for turbulence modelling in a non-inertial frame of reference. It is described by the Euclidean group of transformations and, in p...We investigate the role of extended intrinsic mean spin tensor introduced in this work for turbulence modelling in a non-inertial frame of reference. It is described by the Euclidean group of transformations and, in particular, its significance and importance in the approach of the algebraic Reynolds stress modelling, such as in a nonlinear K-ε model. To this end and for illustration of the effect of extended intrinsic spin tensor on turbulence modelling, we examine several recently developed nonlinear K-ε models and compare their performance in predicting the homogeneous turbulent shear flow in a rotating frame of reference with LES data. Our results and analysis indicate that, only if the deficiencies of these models and the like be well understood and properly corrected, may in the near future, more sophisticated nonlinear K-ε models be developed to better predict complex turbulent flows in a non-inertial frame of reference.展开更多
传统的基于形状信息目标定位算法,对目标发生形变及其阻挡的情况下的检测存在较大的困难。为此,本文提出一种基于非齐次FRAME(Inhomogeneous Filters,Random filed,And Maximum Entropy,缩写IFRAME)模型的感兴趣目标检测算法,该模型由...传统的基于形状信息目标定位算法,对目标发生形变及其阻挡的情况下的检测存在较大的困难。为此,本文提出一种基于非齐次FRAME(Inhomogeneous Filters,Random filed,And Maximum Entropy,缩写IFRAME)模型的感兴趣目标检测算法,该模型由能在位置和方向进行局部扰动的基函数组成,是一种可变形模板,因此一定程度上提高定位算法在物体发生形变情况下的鲁棒性。经过多组实验结果表明,本文所提出的算法能较好地解决目标在发生形变、存在遮挡以及复杂背景下的定位问题。展开更多
Models for the design of assembly processes are considered. Various models for the voice control of an industrial robot are considered: a logical model, semantic networks, a frame model and Petri nets. It is shown tha...Models for the design of assembly processes are considered. Various models for the voice control of an industrial robot are considered: a logical model, semantic networks, a frame model and Petri nets. It is shown that this set of models allows describing the process of designing the technological process for an industrial robot. The logical model of the technological process allows you to define logical relationships. A model based on semantic networks describes the relationship between assembly units in a detail. This allows you to determine the order and method of registration, as well as the mutual orientation of assembly units in the product. The frame model provides the ability to streamline the execution of the build process. A model based on Petri nets allows one to describe the type and sequence of technological transitions. Based on the proposed models, a method of voice control for an industrial robot is developed. The basic principles of voice control for an industrial robot are considered.展开更多
This paper describes a method of the computer aided garment design,and discusses 3-D humanbody,wire frame modelling,approaches of expressing and a shading model of the 3-D garment.
A flexible two degrees of freedom (2-DOF) steering model of multi-axlevehicle (MAV) is presented with considering the effect of frame flexibility based on the classic2-DOF model. A method to calculate the frame flexib...A flexible two degrees of freedom (2-DOF) steering model of multi-axlevehicle (MAV) is presented with considering the effect of frame flexibility based on the classic2-DOF model. A method to calculate the frame flexibility is derived by using three moments equation.The steering stability of MAV is analyzed. The steering performance of MAV is also researched infrequency domain. Simulation results show that the dynamic effects of flexible model are more severethan rigid model and the flexible effect of frame will weaken the steering stability of MAV.Different disposals of steering axles lead to different steering characteristics of MAV. Thein-phase steering mode improves the steering characteristics and stability at high speed. Theanti-phase steering mode increases the steering mobility at low vehicle speed.展开更多
This paper presents an adaptive path following control law to steer underactuated ships along a predefined path at a constant forward speed with uncertain parameters due to changes of added mass matrices.The proposed ...This paper presents an adaptive path following control law to steer underactuated ships along a predefined path at a constant forward speed with uncertain parameters due to changes of added mass matrices.The proposed controller is based on analytic model predictive control and model reference adaptive control.The SerretFrenet frame is used to describe the ship dynamics.The analytic model predictive control provides a systematic method rather than try-and-error method to get appropriate control parameters to guarantee the stability of the closed-loop system,and the well-defined relative degree is guaranteed by introducing output-redefinition.An identification algorithm based on model reference adaptive control is used to identify the uncertain parameters.Numerical simulations are provided to demonstrate the validity of the proposed control law.展开更多
This paper reports two new tests conducted to augment available data highlighting the structural performance of multistory steel frames under progressive collapse. The investigated steel frames had different geometrie...This paper reports two new tests conducted to augment available data highlighting the structural performance of multistory steel frames under progressive collapse. The investigated steel frames had different geometries, different boundary conditions, different collapse mechanisms, different damping ratios and different connections. Overall, the paper addresses how multistory frames would behave when subjected to local damage or loss of a main structural carrying element. The obtained results can form a data base for nonlinear finite element models. The deformations of the investigated steel frames and failure modes under progressive collapse were predicted from the finite element analysis, with detailed discussions presented.展开更多
Aiming at the problems that the classical Gaussian mixture model is unable to detect the complete moving object, and is sensitive to the light mutation scenes and so on, an improved algorithm is proposed for moving ob...Aiming at the problems that the classical Gaussian mixture model is unable to detect the complete moving object, and is sensitive to the light mutation scenes and so on, an improved algorithm is proposed for moving object detection based on Gaussian mixture model and three-frame difference method. In the process of extracting the moving region, the improved three-frame difference method uses the dynamic segmentation threshold and edge detection technology, and it is first used to solve the problems such as the illumination mutation and the discontinuity of the target edge. Then, a new adaptive selection strategy of the number of Gaussian distributions is introduced to reduce the processing time and improve accuracy of detection. Finally, HSV color space is used to remove shadow regions, and the whole moving object is detected. Experimental results show that the proposed algorithm can detect moving objects in various situations effectively.展开更多
文摘This paper advances a new algorithm oriented to geometry modeling (GM) by using frame model. The elemental data structure of frame model is the vertex. This afeoithm provides a general and rapid method. By this way,we can link the vertices to construct the elemental frame and need not consider the topological relation among vertices which consist of the concrete entity. Then, we can combine the elemental frames to complete frame modeling by using aided-line method referring to concrete entity. We will discuss two keystones in the paper. Then we give a 3D geometry modeling example based on wire-frame model using the new algorithm.
文摘By means of analogy, this paper analyses the present functional hierarchyframe model for system maintainability, and presents an improved model. Practical applicationindicates that the improved model is visualized, more convenient and perfected over the perviousmodels.
文摘This paper presents a method for unsupervised segmentation of images consisting of multiple textures. The images under study are modeled by a proposed hierarchical random field model, which has two layers. The first layer is modeled as a Markov Random Field (MRF) representing an unobservable region image and the second layer uses 'Filters, Random and Maximum Entropy (Abb. FRAME)' model to represent multiple textures which cover each region. Compared with the traditional Hierarchical Markov Random Field (HMRF), the FRAME can use a bigger neighborhood system and model more complex patterns. The segmentation problem is formulated as Maximum a Posteriori (MAP) estimation according to the Bayesian rule. The iterated conditional modes (ICM) algorithm is carried out to find the solution of the MAP estimation. An algorithm based on the local entropy rate is proposed to simplify the estimation of the parameters of MRF. The parameters of FRAME are estimated by the ExpectationMaximum (EM) algorithm. Finally, an experiment with synthesized and real images is given, which shows that the method can segment images with complex textures efficiently and is robust to noise.
文摘Isothermal flashless die forging process of Ti - alloy structural air - frame part with varying thickness rib has been modelled in this paper.The results of present study show that a upside - down trapezoid rib would be formed and buckling would occure as blank is reduced,if the thickness of billet is maller than or equal to the thickness of rib. During modelling process of structural air frame part with E type cross - section rib, the saddle or lap would be formed finally at the middle of transverse rib between ribs with increase in deformation.If metal is allowed to flow out at confluence of longitudinal and transverse rib, the lop defect would be eliminated,, but a pipe cavity is obvious on corresponding loca- tion of blank. of defect formation depends on distance of metal flow ,friction,temperature homoge- neity of the blank and complexity of the part.
文摘A “LAG & RLC” visualization algorithm has been presented to display a clear three dimensional structure from stereo slice data which has the characteristics of multiple layer structure. This algorithm is based on wire frame model which can do multiple logical operations and has multiple display effects. It has wide use in biomedical science and computer graphics. The practical system is based on PC with a TVGA adapter at least 512k byte display memory and 2M byte extended memory.
基金Scientific Research Fund of Institute of Engineering Mechanics,China Earthquake Administration under Grant Nos.2016A05 and 2016A06National Natural Science Foundation of China under Grant No.51478441
文摘The fishbone model is a simplified numerical model for moment-resisting frames that is capable of modelling the effects of column-beam strength and stiffness ratios. The applicability of the fishbone model in simulating the seismic responses of reinforced concrete moment-resisting frames of different sets of column-beam strength and stiffness ratios are evaluated through nonlinear static, dynamic and incremental dynamic analysis on six prototype buildings of 4-, 8-and 12-stories. The results show that the fishbone model is practically accurate enough for reinforced concrete frames, although the assumption of equal joint rotation does not hold in all cases. In addition to the ground motion characteristics and the number of stories in the structures, the accuracy of the model also varies with the column-beam stiffness and strength ratios. The model performs better for strong column-weak beam frames, in which the lateral drift patterns are better controlled by the continuous stiffness provided by the strong columns. When the inelastic deformation is large, the accuracy of the model may be subjected to large record-to-record variability. This is especially the case for frames of weak columns.
基金funded by the research-applied project of the Astronomical Institute of Uzbekistan (FA-A5-F014)
文摘This paper presents an option for modern dynamic terrestrial reference system realization in Uzbekistan for user needs. An additive model is explored to predict patterns of time series and investigate means of constructing forecast time series models in the future. The main components(trend, periodical, and irregular) of the KIUB(DORIS) and KIT3, TASH, MADK, and MTAL(GNSS) international stations coordinate time series were investigated. It was shown that seasonal nonlinear trends occurred both in the height(U) component of all stations and the east(E) component of high mountainous stations such as MTAL and MADK. The seasonal periodical portion of the time series determined from the additive model has a complicated pattern for all sites and can be explained as both hydrological signals in the region and improvement of observational quality. Amplitudes of the best-fitting sinusoids in the North component ranged between 1.73 and 8.76 mm; the East component ranged between 0.82 and 11.92 mm; and the Up component ranged between 3.11 and 40.81 mm. Regression analysis of the irregular portion of the height component of the two techniques at the Kitab station using tropospheric parameters(pressure and temperature) was confirmed as only 57% of the stochastic portion of the time series.
文摘We investigate the role of extended intrinsic mean spin tensor introduced in this work for turbulence modelling in a non-inertial frame of reference. It is described by the Euclidean group of transformations and, in particular, its significance and importance in the approach of the algebraic Reynolds stress modelling, such as in a nonlinear K-ε model. To this end and for illustration of the effect of extended intrinsic spin tensor on turbulence modelling, we examine several recently developed nonlinear K-ε models and compare their performance in predicting the homogeneous turbulent shear flow in a rotating frame of reference with LES data. Our results and analysis indicate that, only if the deficiencies of these models and the like be well understood and properly corrected, may in the near future, more sophisticated nonlinear K-ε models be developed to better predict complex turbulent flows in a non-inertial frame of reference.
文摘传统的基于形状信息目标定位算法,对目标发生形变及其阻挡的情况下的检测存在较大的困难。为此,本文提出一种基于非齐次FRAME(Inhomogeneous Filters,Random filed,And Maximum Entropy,缩写IFRAME)模型的感兴趣目标检测算法,该模型由能在位置和方向进行局部扰动的基函数组成,是一种可变形模板,因此一定程度上提高定位算法在物体发生形变情况下的鲁棒性。经过多组实验结果表明,本文所提出的算法能较好地解决目标在发生形变、存在遮挡以及复杂背景下的定位问题。
文摘Models for the design of assembly processes are considered. Various models for the voice control of an industrial robot are considered: a logical model, semantic networks, a frame model and Petri nets. It is shown that this set of models allows describing the process of designing the technological process for an industrial robot. The logical model of the technological process allows you to define logical relationships. A model based on semantic networks describes the relationship between assembly units in a detail. This allows you to determine the order and method of registration, as well as the mutual orientation of assembly units in the product. The frame model provides the ability to streamline the execution of the build process. A model based on Petri nets allows one to describe the type and sequence of technological transitions. Based on the proposed models, a method of voice control for an industrial robot is developed. The basic principles of voice control for an industrial robot are considered.
文摘This paper describes a method of the computer aided garment design,and discusses 3-D humanbody,wire frame modelling,approaches of expressing and a shading model of the 3-D garment.
文摘A flexible two degrees of freedom (2-DOF) steering model of multi-axlevehicle (MAV) is presented with considering the effect of frame flexibility based on the classic2-DOF model. A method to calculate the frame flexibility is derived by using three moments equation.The steering stability of MAV is analyzed. The steering performance of MAV is also researched infrequency domain. Simulation results show that the dynamic effects of flexible model are more severethan rigid model and the flexible effect of frame will weaken the steering stability of MAV.Different disposals of steering axles lead to different steering characteristics of MAV. Thein-phase steering mode improves the steering characteristics and stability at high speed. Theanti-phase steering mode increases the steering mobility at low vehicle speed.
基金the National Natural Science Foundation of China (No. 50779033)the National High Technology Research and Development Program (863) of China (No. 2007AA11Z250)
文摘This paper presents an adaptive path following control law to steer underactuated ships along a predefined path at a constant forward speed with uncertain parameters due to changes of added mass matrices.The proposed controller is based on analytic model predictive control and model reference adaptive control.The SerretFrenet frame is used to describe the ship dynamics.The analytic model predictive control provides a systematic method rather than try-and-error method to get appropriate control parameters to guarantee the stability of the closed-loop system,and the well-defined relative degree is guaranteed by introducing output-redefinition.An identification algorithm based on model reference adaptive control is used to identify the uncertain parameters.Numerical simulations are provided to demonstrate the validity of the proposed control law.
文摘This paper reports two new tests conducted to augment available data highlighting the structural performance of multistory steel frames under progressive collapse. The investigated steel frames had different geometries, different boundary conditions, different collapse mechanisms, different damping ratios and different connections. Overall, the paper addresses how multistory frames would behave when subjected to local damage or loss of a main structural carrying element. The obtained results can form a data base for nonlinear finite element models. The deformations of the investigated steel frames and failure modes under progressive collapse were predicted from the finite element analysis, with detailed discussions presented.
文摘Aiming at the problems that the classical Gaussian mixture model is unable to detect the complete moving object, and is sensitive to the light mutation scenes and so on, an improved algorithm is proposed for moving object detection based on Gaussian mixture model and three-frame difference method. In the process of extracting the moving region, the improved three-frame difference method uses the dynamic segmentation threshold and edge detection technology, and it is first used to solve the problems such as the illumination mutation and the discontinuity of the target edge. Then, a new adaptive selection strategy of the number of Gaussian distributions is introduced to reduce the processing time and improve accuracy of detection. Finally, HSV color space is used to remove shadow regions, and the whole moving object is detected. Experimental results show that the proposed algorithm can detect moving objects in various situations effectively.
