Analysis and compare of location technologies supporting LBS

Location technology is the key part of location based service. Different technologies have different accuracy, modifying to network and cost of operating. Also these technologies have limitation to network. This paper compares existing popular location technologies and gives some suggestions about choosing of location technologies in GSM and CDMA systems.     

Hybrid location determination technology within urban and indoor environment based on Cell-ID and path loss

The location determination technology based on simple delay evaluations or GPS is not accurate enough or even impossible in urban and indoor environments due to the multi-path propagation. To enhance the location accuracy and reduce the operation cost within these environments, this paper proposes a novel hybrid location determination technology which combines CELL-ID with the database correlation method. The proposed method generate the prediction database of path loss according to CELL-ID, and after the computation the smallest squared error of measured path loss and the prediction path loss,the location of the mobile terminal is decided by the coordinates of the best matching matrix entry.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents. A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

基于多种知识的盲文翻译的研究

盲文到汉字的转换研究 ,分为盲文到拼音和拼音到汉字的转换研究。论文通过引入音码表 ,很好地解决了盲文到拼音转换中的歧义问题。对于拼音到汉字的转换 ,采用Markov模型 ,使用平滑算法解决此模型中的数据稀疏问题 ,并且对通常使用的字级别二元模型的平滑算法进行了改进以适应词级别二元模型。为每一个拼音句子建立一个拼音到汉字转换多部图 ,并在此转换多部图中使用 Viterbi算法搜索一条具有最大似然度的汉语句子 ,或使用 N - Best算法搜索具有头 N大似然度的 N个汉语句子。同时研究了从 1选到 N选的转换判据 ,以进行自动的 N - Best转换。实验表明 ,盲文到汉字转换系统的转换正确率为 94.38% ,若剔除专有名词 ,转换正确率还可上升 2个百分点。对 N - Best搜索算法的测试表明 5选正确率比 1选正确率提高了 3个百分点