A novel approach to realistic collision-free animation of the upper limb was proposed.According to the obstacle-avoidance strategy of human hand,the movement trajectory was computed by manipulability model and minimum...A novel approach to realistic collision-free animation of the upper limb was proposed.According to the obstacle-avoidance strategy of human hand,the movement trajectory was computed by manipulability model and minimum-jerk based interpolation.In each key frame,an improved in～verse kinematics method was adopted to obtain a believable posture of the upper limb.By comparing with the real movement data obtained from the motion capture device,the resultant animation was testified to be natural.This method can be performed in interactive time,and therefore is applicable in animation edit and control of virtual humans.展开更多
Ports operating in the same geographical range face significant competition among them. In such setting, less competitive ports may continually lose patronage of shippers （indigenous to them） to adjacent ones with b...Ports operating in the same geographical range face significant competition among them. In such setting, less competitive ports may continually lose patronage of shippers （indigenous to them） to adjacent ones with better attributes. The extent of and determinants of inter-port competition in the West Africa＇s coast are of interest to port administrators/operators who risk losing significant portion of their domestic generated cargo traffic to competing neighbouring ports. In this paper, we explore the question of what port specific attributes serve as competitive basis for West Africa＇s coastal ports operating in proximity to the other. Through a survey, users of these ports were asked to identify port specific attributes which they consider when deciding which port to use for shipments making. To enrich our empirical model, data collected from the survey were augmented with secondary data （on the identified attributes） obtained from the respective ports. Statistical evidence from data analysis suggests that ports operating in proximity in the West Africa＇s coast compete on the basis of attributes that minimise costs for port users, viz： ships＇ pre-berthiig time, ship turnround time, crane efficiency and availability of cargo spaces （proxied by frequency of ship calls）. Policy implications of the findings were discussed.展开更多
In order to deal with the problems of laying and assembly planning of slender flexible parts in electromechanical products,a novel approach to operate the physically-based slender flexible parts in an augmented realit...In order to deal with the problems of laying and assembly planning of slender flexible parts in electromechanical products,a novel approach to operate the physically-based slender flexible parts in an augmented reality environment is presented in this paper.A discrete dynamic method is used to efficiently build the physical model of slender flexible parts,which is very well suited for interactive operation in the augmented reality environment.In this model,bending penalty force can be calculated by the bending energy function to improve dynamic bending behavior,and a penalty method is used to simplify the calculation of geometric torsion.With a reasonable construction of augmented reality environment,a real-time interactive algorithm based on the operating panel is proposed to enable users to interact with the virtual slender flexible parts in the mixed reality-based scene.A case study in the augmented reality environment shows that the proposed approach is efficient and feasible.展开更多
基金Supported by Science and Technology Project of Tianjin(No.06YFGZGX06200).
文摘A novel approach to realistic collision-free animation of the upper limb was proposed.According to the obstacle-avoidance strategy of human hand,the movement trajectory was computed by manipulability model and minimum-jerk based interpolation.In each key frame,an improved in～verse kinematics method was adopted to obtain a believable posture of the upper limb.By comparing with the real movement data obtained from the motion capture device,the resultant animation was testified to be natural.This method can be performed in interactive time,and therefore is applicable in animation edit and control of virtual humans.
文摘Ports operating in the same geographical range face significant competition among them. In such setting, less competitive ports may continually lose patronage of shippers （indigenous to them） to adjacent ones with better attributes. The extent of and determinants of inter-port competition in the West Africa＇s coast are of interest to port administrators/operators who risk losing significant portion of their domestic generated cargo traffic to competing neighbouring ports. In this paper, we explore the question of what port specific attributes serve as competitive basis for West Africa＇s coastal ports operating in proximity to the other. Through a survey, users of these ports were asked to identify port specific attributes which they consider when deciding which port to use for shipments making. To enrich our empirical model, data collected from the survey were augmented with secondary data （on the identified attributes） obtained from the respective ports. Statistical evidence from data analysis suggests that ports operating in proximity in the West Africa＇s coast compete on the basis of attributes that minimise costs for port users, viz： ships＇ pre-berthiig time, ship turnround time, crane efficiency and availability of cargo spaces （proxied by frequency of ship calls）. Policy implications of the findings were discussed.
基金supported by the Basic Research Project of China National 12th Five-year Plan
文摘In order to deal with the problems of laying and assembly planning of slender flexible parts in electromechanical products,a novel approach to operate the physically-based slender flexible parts in an augmented reality environment is presented in this paper.A discrete dynamic method is used to efficiently build the physical model of slender flexible parts,which is very well suited for interactive operation in the augmented reality environment.In this model,bending penalty force can be calculated by the bending energy function to improve dynamic bending behavior,and a penalty method is used to simplify the calculation of geometric torsion.With a reasonable construction of augmented reality environment,a real-time interactive algorithm based on the operating panel is proposed to enable users to interact with the virtual slender flexible parts in the mixed reality-based scene.A case study in the augmented reality environment shows that the proposed approach is efficient and feasible.
