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Aiming at the disadvantage of the gain difference of the underwater satellite signal received by the towed antenna of the underwater vehicle, a new type of dual-radiator antenna, which can increase the gain of the receiving antenna in seawater by adding a parasitic radiator, is designed, which can effectively improve the gain of the receiving antenna underwater and reduce the reflection coefficient. The models of the half-wave dipole antenna and the new double-radiator antenna are established and the indexes such as reflection coefficient, gain, and direction graph are simulated. A real antenna and a test platform are built, and the gain simulation results are verified by using the reduced-scale model method and double antenna comparison method. Simulation and experimental results show that the new dual-radiator antenna is a towed antenna suitable for the underwater vehicle to receive satellite signals in the 344MHz~351MHz band.

Nowadays, Internet technology has flourished and become a hot, infiltrating into all aspects of our lives. The education industry has also progressed with the innovation of technology, and online learning has emerged. Developers of online learning always put their own learning resources on the platform for the students to use. Students can learn by searching for content that they are interested in. But looking up in massive content may waste too much time. Therefore, the system can recommend different learning resources for different students or not through some historical browsing and the learning behavior or other contents becomes a important problem to be solved. This paper is aimed at this issue mainly to study the personalized recommendation of learning platform based on the students' learning behaviors.

Audio segmentation and classification is the basis of broadcast audio processing in the broadcast domain. A number of methods have been developed over the years in order for the broadcast station to segment and classify the audio into 7 classes, which are: male speech, female speech, speech with noise, speech with music, noise, music, and silence. Some of the major methods include SVM, GMM and HMM among others, however the overall accuracy of these existing methods is not satisfactory. This paper, therefore proposes an adaptive CNN method which classifies clips directly based on audio sample points. To our knowledge, this is the first work to do segmentation and classification in broadcast domain by Adaptive CNN. Each convolutional layer is equivalent to the clip feature extraction. The study uses the method of Adaptive CNN by increasing the amount of computation to ensure that the most suitable features can be extracted. In other words, Adaptive CNN increases the process of feature selection compared to CNN. A large number of experiments were carried out and compared with other approaches and the results show that the Adaptive CNN technique achieved a significant error reduction.

Based on the characteristics of channel noise of Super Low Frequency (SLF) channel which is mainly formed with white Gaussian noise and impulse noise caused by thunders, and displays an obvious non-Gaussian feature, the thesis proceeds an analysis on multiple channels coding, designs a channel coding scheme for SLF communication and carries out a simulation analysis.

At present, the submarines employ towed antennas to receive super low frequency(SLF) signal, which not only limits the mobility and safety of submarine, but also exists receiving blind zone. On account of the advantages of magnetic antenna, such as small size, high sensitivity and strong anti-jam capacity, it is proposed to receive SLF signals. In accordance with the structure and working principle of the magnetic antenna, simplified equivalent circuit model is established. By means of analyzing parameters of the core and coils, magnetic antenna which works between 30Hz and 200Hz is designed. In order to reduce distributed capacitance, winding method is analyzed and optimized and group winding solution is proposed subsequently. By measuring the sensitivity in the circumstance of uniform magnetic field, the measurement value shows that the method has effectiveness on reducing distributed capacitance and raising resonant frequency.

According to the situation that the system of power line communication and very low frequency communication is interfered by severe impulse interference, the method of suppressing impulse interference by using spread-time technique is presented, and the ability to suppress impulse interference with spread-time technique is analyzed, and the selection of the spread-time code according to the characteristic of the extended time signal is researched. Finally, the availability of spread-time technique that it can suppress the pulse noise is verified, for emulation analyzing by MATLAB6.5 soft.