Towed cable systems are frequently used in marine measurements where the length of the towed cable varies during launch and recovery. In this paper a novel method for modeling variable length cable systems is introduc...Towed cable systems are frequently used in marine measurements where the length of the towed cable varies during launch and recovery. In this paper a novel method for modeling variable length cable systems is introduced based on the finite segment formulation. The variable length of the towed cable is described by changing the length of the segment near the towing point and by increasing or decreasing the number of the discrete segments of the cable. In this way, the elastic effects of the cable can be easily handled since geometry and material properties of each segment are kept constant. Experimental results show that the dynamic behavior of the towed cable is consistent between the model and the physical cable. Results show that the model provides numerical efficiency and simulation accuracy for the variable length towed system.展开更多
This paper presents an algorithm for extracting lines from hand drawings.It starts from contour pixel tracing, fits them into contour segments, and thenextracts skeleton lines from the contour segments. The algorithm ...This paper presents an algorithm for extracting lines from hand drawings.It starts from contour pixel tracing, fits them into contour segments, and thenextracts skeleton lines from the contour segments. The algorithm finds all con-tours in one scan of the input matrix without detecting and marking multiplepixels. In line extraction, the method Elastic Contour Segment nacing is pro-posed which extracts lines by referring to the contour segments at both sides,overcoming noise and passing through blotted areas by fitting and extrapolation.Experiments on free hand mechanical drawings, sketches, letter/numerals,as well as Chinese characters are carried out and satisfactory results are achieved.展开更多
基金This work was financially supported by National Hi-Tech R&D Program of China (863 Program)( Grant No2006AA04Z127)New Century Excellent Talents (NCET) of Tianjin University,2005
文摘Towed cable systems are frequently used in marine measurements where the length of the towed cable varies during launch and recovery. In this paper a novel method for modeling variable length cable systems is introduced based on the finite segment formulation. The variable length of the towed cable is described by changing the length of the segment near the towing point and by increasing or decreasing the number of the discrete segments of the cable. In this way, the elastic effects of the cable can be easily handled since geometry and material properties of each segment are kept constant. Experimental results show that the dynamic behavior of the towed cable is consistent between the model and the physical cable. Results show that the model provides numerical efficiency and simulation accuracy for the variable length towed system.
文摘This paper presents an algorithm for extracting lines from hand drawings.It starts from contour pixel tracing, fits them into contour segments, and thenextracts skeleton lines from the contour segments. The algorithm finds all con-tours in one scan of the input matrix without detecting and marking multiplepixels. In line extraction, the method Elastic Contour Segment nacing is pro-posed which extracts lines by referring to the contour segments at both sides,overcoming noise and passing through blotted areas by fitting and extrapolation.Experiments on free hand mechanical drawings, sketches, letter/numerals,as well as Chinese characters are carried out and satisfactory results are achieved.
