In this paper an automatic visual method of seam recognizing and seam tracking based on textural feature matching was proposed, in order to recognize the weld of multi-layer or multi-pass welding in which the weld is ...In this paper an automatic visual method of seam recognizing and seam tracking based on textural feature matching was proposed, in order to recognize the weld of multi-layer or multi-pass welding in which the weld is difficult to be recognized by conventional visual methods. This method focuses on the obvious difference of image textural feature between the weld region and the base metal region, as well as the similarity of the textural features along the welding direction. The method consists of the following steps : setting image template and choosing the edge region as ROI ( region of interest ), extracting the image textural feature of the template and the edge region, feature matching, and recognition of weld region. Experiment showed that the method proposed was effective for weld seam recognition in multi-layer welding.展开更多
Sequence alignment is a common method for finding protein structurally conserved/similar regions. However, sequence alignment is often not accurate if sequence identities between to-be-aligned se- quences are less tha...Sequence alignment is a common method for finding protein structurally conserved/similar regions. However, sequence alignment is often not accurate if sequence identities between to-be-aligned se- quences are less than 30%. This is because that for these sequences, different residues may play similar structural roles and they are incorrectly aligned during the sequence alignment using substitu- tion matrix consisting of 20 types of residues. Based on the similarity of physicochemical features, residues can be clustered into a few groups. Using such simplified alphabets, the complexity of protein sequences is reduced and at the same time the key information encoded in the sequences remains. As a result, the accuracy of sequence alignment might be improved if the residues are properly clustered. Here, by using a database of aligned protein structures (DAPS), a new clustering method based on the substitution scores is proposed for the grouping of residues, and substitution matrices of residues at different levels of simplification are constructed. The validity of the reduced alphabets is confirmed by relative entropy analysis. The reduced alphabets are applied to recognition of protein structurally conserved/similar regions by sequence alignment. The results indicate that the accuracy or efficiency of sequence alignment can be improved with the optimal reduced alphabet with N around 9.展开更多
French overseas departments and territories are known for their rich and diverse tropical floras,associated with traditional health knowledge,skills,and practices.Many people find necessary to further highlight this s...French overseas departments and territories are known for their rich and diverse tropical floras,associated with traditional health knowledge,skills,and practices.Many people find necessary to further highlight this still very much alive cultural heritage,because transmission to future generations is not assured.Official recognition of展开更多
基金This research is supported by the National Natural Science Foundation of China (No. 50875145) and the National High Technology Research and Development Program ("863" Program) of China (Contract No. 2007AAO4Z258).
文摘In this paper an automatic visual method of seam recognizing and seam tracking based on textural feature matching was proposed, in order to recognize the weld of multi-layer or multi-pass welding in which the weld is difficult to be recognized by conventional visual methods. This method focuses on the obvious difference of image textural feature between the weld region and the base metal region, as well as the similarity of the textural features along the welding direction. The method consists of the following steps : setting image template and choosing the edge region as ROI ( region of interest ), extracting the image textural feature of the template and the edge region, feature matching, and recognition of weld region. Experiment showed that the method proposed was effective for weld seam recognition in multi-layer welding.
基金the National Natural Science Foundation of China (Grant Nos. 90403120, 10474041 and 10021001)the Nonlinear Project (973) of the NSM
文摘Sequence alignment is a common method for finding protein structurally conserved/similar regions. However, sequence alignment is often not accurate if sequence identities between to-be-aligned se- quences are less than 30%. This is because that for these sequences, different residues may play similar structural roles and they are incorrectly aligned during the sequence alignment using substitu- tion matrix consisting of 20 types of residues. Based on the similarity of physicochemical features, residues can be clustered into a few groups. Using such simplified alphabets, the complexity of protein sequences is reduced and at the same time the key information encoded in the sequences remains. As a result, the accuracy of sequence alignment might be improved if the residues are properly clustered. Here, by using a database of aligned protein structures (DAPS), a new clustering method based on the substitution scores is proposed for the grouping of residues, and substitution matrices of residues at different levels of simplification are constructed. The validity of the reduced alphabets is confirmed by relative entropy analysis. The reduced alphabets are applied to recognition of protein structurally conserved/similar regions by sequence alignment. The results indicate that the accuracy or efficiency of sequence alignment can be improved with the optimal reduced alphabet with N around 9.
文摘French overseas departments and territories are known for their rich and diverse tropical floras,associated with traditional health knowledge,skills,and practices.Many people find necessary to further highlight this still very much alive cultural heritage,because transmission to future generations is not assured.Official recognition of