In order to ensure that users accurately and quickly obtain what they are interested in from a great amount of knowledge information, an information retrieval algorithm based on the iterative extraction of key phrases is presented by synthetically considering the head information (title, abstract and keywords) and key body content of a document. By this algorithm, the precision rate of topic extraction reaches 83% with the efficiency being unaffected, and the performance of topic information retrieval is also increased.

Experimental results indicate that, by reasonably adjusting the relativity weights of candidate keyphrases on the basis of Term Frequency-Inverse Document Frequency and employing the proposed iterative extraction algorithm, the retrieval of topic information can achieve remarkable precision.

In computer aided design and some correlative fields,it is needed to fit curves accurately. For this reason,a new algorithm to fit curves based on key points which were extract iteratively is presented in this paper.

Compared with the center position gotten by centrobaric method and self-adaptive threshold method,it is found that the proposed method enables to extract the light stripe center position exactly and steadily to outperform with a precision of 10 μm and higher anti-interference capacity.

The atmosphere correction of multi angle remote sensing should consider the atmosphere surface coupled system and iterative inversion to calculate the coupled factor.This paper makes use of Rahman BRDF model and the iterative BRDF atmospheric correction method for NOAA satellite data to obtain multi angle atmosphere corrected images. The experiment has proved the feasibility of applying the MODIS atmosphere correction method to existing multi angle NOAA satellite data. Spectral curves after BRDF atmosphere...

The atmosphere correction of multi angle remote sensing should consider the atmosphere surface coupled system and iterative inversion to calculate the coupled factor.This paper makes use of Rahman BRDF model and the iterative BRDF atmospheric correction method for NOAA satellite data to obtain multi angle atmosphere corrected images. The experiment has proved the feasibility of applying the MODIS atmosphere correction method to existing multi angle NOAA satellite data. Spectral curves after BRDF atmosphere correction match the surface curves mostly and the iteration converges fast. Under find weather condition, the error is very small after only one iteration. By comparison, the difference of image reflectance between the original image and the image after BRDF atmosphere correction can reach 30%. The variation trend of original images reflectance is different greatly from the measuring value of ground along with the angle changing. This result shows that BRDF atmosphere correction is indispensable,and even that the NOAA satellite data should not be used to quantitative remote sensing research,if it have not been corrected for atmosphere. Now, obtaining multi angle satellite remote sensing data exists a lot of difficulty, and the atmosphere correction is an indispensable step in multi angle remote sesing application for present obtainable abundance NOAA data.All these are only preliminary experimental results, and there still are some problems needed to do further study.For example, under bad weather condition,what will be the atmosphere correction result? It other BRDF modes such as Ambrals are adopted, will the atmosphere correction result be the same with the Rahmans? These also need the researchs on multi angle remote sensing theory to do futher study.

In computer aided design and some correlative fields,it is needed to fit curves accurately.For this reason,a new algorithm to fit curves based on key points which were extract iteratively is presented in this paper.It searchs the key points between tow end points using iterative moethod.It tow new sequent key points are added,the former key point between them will be deleted to reduce the number of the key points.This approach could control the precision by some threshold.Because the threshold is alterable,designers...

In computer aided design and some correlative fields,it is needed to fit curves accurately.For this reason,a new algorithm to fit curves based on key points which were extract iteratively is presented in this paper.It searchs the key points between tow end points using iterative moethod.It tow new sequent key points are added,the former key point between them will be deleted to reduce the number of the key points.This approach could control the precision by some threshold.Because the threshold is alterable,designers could set it according to their need until a certain precisionis gotten.The principle of this algorithm,along with its realizing process and the results is introduced in this paper.According to the experiments,this algorithm is easy to compute and it can make a nice fitting using least but precise keypoints

In order to ensure that users accurately and quickly obtain what they are interested in from a great amount of knowledge information, an information retrieval algorithm based on the iterative extraction of key phrases is presented by synthetically considering the head information (title, abstract and keywords) and key body content of a document. By this algorithm, the precision rate of topic extraction reaches 83% with the efficiency being unaffected, and the performance of topic information retrieval is also...

In order to ensure that users accurately and quickly obtain what they are interested in from a great amount of knowledge information, an information retrieval algorithm based on the iterative extraction of key phrases is presented by synthetically considering the head information (title, abstract and keywords) and key body content of a document. By this algorithm, the precision rate of topic extraction reaches 83% with the efficiency being unaffected, and the performance of topic information retrieval is also increased. Experimental results indicate that, by reasonably adjusting the relativity weights of candidate keyphrases on the basis of Term Frequency-Inverse Document Frequency and employing the proposed iterative extraction algorithm, the retrieval of topic information can achieve remarkable precision.