Applied Mechanics and Materials Vols. 519-520

Abstract: Partially blind signature is an important technique in secure electronic cash system. Recently, Zhang et al. presented the first certificateless partially blind signature scheme and constructed an electronic cash system based on this scheme. They claimed that their certificateless partially blind signature scheme is secure in the random oracle model. However, in this paper, we demonstrate the scheme is not secure. Our attack indicates that a malicious KGC in the electronic cash system based on Zhang et al.'s certificateless partially blind signature can forge valid electronic coins without being detected by the bank. It will result in loss of the bank.

Abstract: With the popularization of three dimensional (3D) video on TV, some related aspects, such as broadcast television network transmission, technology application, and content products and so on, will face the challenges of the new technology. Rapid progress has been achieved in the China Mobile Multimedia Broadcasting (CMMB) technology, 3D TV technology applied in the mobile TV will become the bright spot in the future. This paper firstly introduces the transmission modes of 3D TV, and then gives the technology solution of 3D TV and the upgrade solution of electronic service guide Electronic Service Guide (ESG) based on CMMB. Test result shows that the new system with 3D video can work correctly when the 3D video was encoded with H.264 standard and the image resolution was conformed to the standard definition (320x240).

Abstract: Traditional Chinese headdress is an important part of the traditional Chinese culture, which provides rich material for computer animation. The creation process of traditional Chinese headdress model in computer animation is complex working and time-consuming. This study establishes the traditional Chinese headdresses database, which covers from Tang Dynasty to Qing Dynasty. According to the characteristics of the traditional Chinese headdress, this study develops an intelligent Traditional Chinese Headdress system by MEL, which can import models into the scene and change attributes related with models efficiently. The system is the combination among computer technology, animation art and traditional Chinese culture. It will improve the efficiency and quality in the computer animation creation.

Abstract: A 3D human facial model was made based on the MPEG-4 standard. A method of synthesis of mouth animation based on a entire Chinese sentence was put forward, according to the influence of Chinese pronunciation rules such as co-articulation sufficiently. The method computes the extent of influence between current phoneme and the one next to it, and constructs the continuous mouth-shape sequence. Then filter the phoneme which has little effect on the last and the next one when pronouncing continuously. The 3D facial model was driven to synthesize smooth and realistic animation. After the experiments, it is proved that the method has a good versatility and reliability, which can be used on different kinds of 3D models. At the same time, the method can effectively improve the problem of co-articulation in continuous Chinese pronunciation, which makes the synthesis of mouth animation more smooth, more fluent, and more close to real pronunciation of people.

Abstract: There are not any kind of e-textbooks could offer customized content, although e-textbooks in the teaching field has already spread. The purpose of this study is making e-textbooks to meet the individual needs of the audience. The study is bases on EPUB, XML and XHTML. It will explore how to realize personalized and customized e-textbook client. The study is bases on the frame of server and client.

Abstract: The mobile TV technology of CMMB has been widely used in China. Currently, the transmission technology of mobile TV is downward broadcasting. With the development of Three Networks Convergence, bidirectional interactive broadcasting will become one of the important directions of CMMB. This paper introduces CMMB data broadcasting agreements and two major service models. A detailed scheme on interactive broadcasting from both national operations and local operators is designed based on the above models. Test results on the terminal show that the rich media of music and arts can work on the terminal by CMMB technology.

Abstract: MAC protocol analysis and comparison to the multimedia communication theory as the framework, firstly discusses the requirement of communication network in computer networks and multimedia applications. MAC protocols oriented to wireless sensor networks are compared and analyzed. Summary of CSMA/CA, CSMA/CD, S-MAC and basic principles and applicable occasions, main parameters is made. Properties of the three MAC protocols is compared. The results of this study provides reference for MAC protocol oriented to multimedia communications.

Abstract: OFDM modulation signal based on different Pseudo-random Noise sequences cant be discriminated in time domain in OFDM system. In order to resolve this problem, the time-domain sliding correlation technique based on ZC sequences is proposed, and the relations between the time-domain correlation properties and the length of the sequence are analyzed. On the basis of the analysis of the technique, the optimum scheme of time-domain sliding correlation is done by the aid of the comparison of the auto-correlation gain on the condition of limited symbol length and band-width. Simulation results in AWGN channel show that OFDM demodulation signal based on ZC sequences designed newly in this work has good auto-correlation and cross-correlation properties in time domain.

Abstract: With the rapid development of mobile internet, the projector becomes the terminal of mobile internet because of the network module embedded in smart projectors, which can provide a more convenient viewing experience. For traditional mini projector just as simple display equipment, the integration of Android operating system makes mini projector smarter, it is equivalent to a simple PC with projection function. This paper discusses the projection screen keystone distortion phenomenon of mini projector equipped with Android operating system under limiting projection environment because of different placement angle and how to eliminate the above-mentioned distortion, after elaborating the software and hardware architecture of smart mini projector, it focuses upon an analysis on how to achieve automatic correction of the projection screen using the digital acceleration sensor in hardware driver of the Android operating system.

Abstract: As the development of the mobile communication and the computational capability of the mobile terminals, more users use their mobile devices to play music. In this work, an online music recommendation system is designed for mobile services, which consists of two modules: offline processing and online recommendation. The offline module labels all the music into different categories, by which the music items libraries corresponding to the tags are constructed and the rating matrixs are consequently built. The online module integrates the context information, by which the matched rating matrix is retrieved. By using the collaborative filtering model with matrix completion algorithm, the music recommendations that suit the user and the situation are offered. The proposed recommendation system improves the precision of the recommendation by integration the context information of the users, and augments the online computational capability because the matrix scale is reduced by constructing the rating matrices for the music in the different tag libraries. A large number of experiments demonstrate that the proposed system is designed to be robust and effective to the music recommendation and efficient to the online recommendation for the mobile services.