| The development level of Short Message Service (SMS) is improved with an amazing speed after its promotion by China Mobile and China Unicom in the year of 2000. The mobile phone network marked with short message will likely become "the Fifth Medium"and affect everyone's daily life. When people enjoy the convenience supplied by "Thumb Culture", some negative effects have appeared. A lot of spam short messages, including pornography, reactionary speech, swindles, threat and harassment, are spread around, and mobile phone users are flooded with them. All above will lead to the unsteadiness of society. This phenomenon draws NPC & CPPCC conferences' morn attention in 2008. So it has become a great problem to be solved immediately. According to the problems existed in SMS, the design and implementation of mobile phone spam short message real-time filtering system, which is applied on Microsoft Windows CE and based on .NET Compact Framework, are proposed.Microsoft Windows CE is an embedded OS which has more function. It supplies a lot of services based on network, e.g. Internet,remote control protocol and VoIP. It is also one of the Operating Systems which are chosen by current smart phone. But Windows CE does not have any security schemes, so doing research on mobile terminal short message filtering technology based on Windows CE is very useful.The current filtering system on the Internet can realize the function of E-mail filtering perfectly, but with the fast development of Internet, it's necessary to solve the problem that users mainly face by researching short message supervising technology under the environment of mobile terminal. The security supervision to short message is a new subject. Meanwhile the process of SMS is complex; the access mode is flexible and changeable; the knowledge scope referred to is also very broad. So in order to let people have an entire and detailed cognition, the function requirement and implementation technology to the spam short message filtering system are studied deeply. The main works are as follows:1. The appearance and development of SMS are analyzed. Differences among General Message, Enhanced Message Service and Multimedia Message Service are compared. The present situation and development platform of spam short message are also studied. In this dissertation, we put more emphasis on the basic process of the short messages' sending and receiving, and indicate that the security risk in SMS is mainly existed in the part of accessing, the center of SMS and the gateway of SMS.2. Three supervision mechanisms used broadly on the Internet, such as real-time filtering mechanism, phone bill analyzing mechanism and protocol supervision mechanism are analyzed and compared. According to WinCE mobile phone, Pocket Outlook service is studied based on the introduction of the data storage of mobile device. By using this service, the reception and filtering of short messages could be realized. Meanwhile a new method to spam short message filtering is proposed.3. The basic theory and supervising method to SMS are analyzed. While the characteristic of Windows CE platform and .NET Compact Framework are introduced too.4. According to the theorem of short message filtering technology, considering the limitation of resources on mobile terminal and the characteristic of users, the system requirement is analyzed deeply. Finally, data structure, function requirement, performance requirement, user interface requirement, development environment and tools are determined.5. The description to the process of realizing short message filtering system. C# is programming language with strong type. Because of its simple grammar and strong power of expression, C# is selected to develop the spam short message filtering system.6. After the development of spam short message filtering system, its testing scheme is drawn up and executed. The result of functional test and performance test has also been presented. It proved that the system has achived design objectives. |
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