Focusing on the shortcomings such as long delay, high Bit Error Rate (BER), asymmetric channel in deep space communication, high redundancy and low decoding success rate of short LT codes, a new deep space data delivery strategy based on Optimized LT (OLT) codes was proposed. First, the OLT codes was given by adjusting the degree distribution function, and adopting new packet selection strategy and joint decoding algorithm. Then, a deep space data delivery strategy based on OLT codes was presented, in which the sender encoded the data file and sent it out, and the receiver got the data by decoding the encoded packets by use of joint decoding algorithm. The simulation results show that compared with LT codes, OLT codes can improve decoding success rate and reduce redundancy. Besides, compared with CFDP, the proposed strategy can effectively reduce the delay and improve the validity and reliability of data delivery, especially in the case of high packet loss rate.
To solve the high consumption problem of fast video Shot Boundary Detection (SBD), an improved Shot Boundary Detection (SBD) method was proposed based on video pre-processing. Adaptive threshold was taken to select the candidate segments which may contain shot boundaries, the beginning frame was detected by comparing the similarity value between the first frame and the rest frames in the candidate segments, and then cut was detected immediately. Gradual transition would be detected if no cut was detected. Candidate segments had to be adjusted to ensure the whole transition was located in the same segment. Ending frame was confirmed by comparing the similarity value between the beginning frame and the rest frames in segment. Experimental results demonstrate that the proposed algorithm achieves an accuracy above 90% and the time cost is reduced 15.6%-30.2% compared with inverted triangle pattern matching method. The proposed algorithm satisfies the need of accuracy and improves detection speed compared with the traditional methods which need detection for both cut and gradual transition.
Based on component technology, a method of OWL-based Web service was proposed. Combined with atom-component and ontology, the Web service component granularity became a single function component. The application of OWL and ontology improved Web service at information and knowledge.