SL4AANDITS RELATED TECHNOLOGIES

SL4AANDITS RELATED TECHNOLOGIES

A. the Working Principle of SL4A The full name of SL4A is Scripting Layer for Android. It is a software running on Android to support the development of android applications using scripting languages, which makes android application development easier and faster. SL4A supports many scripting languages, including Python, Perl, JRuby, Lua, BeanShell, JavaScript, Tcl and shell, etc. SL4A imple ments the JSON-RPC interfaces to access the android native services. The JSON-RPC re mote call is the working principle of SL4A. The SL4A architecture is shown in Fig. 1. It shows that SL4A is composed of client and server. As long as compatible with the JSON-RPC commun ication interface provided by SL4A RPC Server, any programming languages as client can access the android native services provided by the SL4A RPC Server. A client is usually a SL4A Supported Client Script Engine and it is responsible for launching JSON-RPC re mote calls. The SL4A RPC Server to receive JSON-RPC call fro m a client will call java android API to provide the android native services for the client. The communication process of the client and the server is that the client parses android service call fro m the script application firstly, and the client uses SL4A JSON RPC interface to send android service request secondly, and the server invokes java android api to complete the request and retrace the call path to return executed results to the client lastly. About SL4A technology, Xing explored SL4A and developed demonstration applications, such as a map application[7] , based on JavaScipt and PHP[8]

B. TTS and ASR Technologies The full na me of TTS is Te xt To Speech. The task of TTS is to convert text information into audible speech information. The initial version of Android that supports TTS is 1.6. Pico and iFLYTEK are common TTS softwares. This type of TTS software provides a TTS engine, language packs, and TTS interfaces. TTS interfaces of Pico and iFLYTEK are compatible with the TTS interfaces of the Android system. The TTS engine is separated from language packs. SL4A apps use TTS functions of Pico and iFLYTEK by calling TTS interfaces of Android system. The advantages of iFLYTEK are good interface compatibility and easy expansion of multi language, but the lack of iFLYTEK can not dynamically ad just speech parameters, such as language and speaking speed, during the run time of programs. The full na me of ASR is Automated Speech Recognition. It is a technology to convert human voice into text. At present, the two companies of iFLYTEK and Ba idu are the fa mous developers on ASR technology in China. ASR interfaces of iFLYTEK a re compatible with the ASR interfaces of the Android system. SL4A apps can use iFLYTEK ASR functions by calling ASR interfaces of the Android system. iFLYTEK ASR software supports Android, iOS and Windows Phone and other mainstream system. And it supports Chinese and English and many other languages. And it has high recognition rate and recognition speed.