Abstract: With the development of technology and increase of application requirements,a lot of sensors and network interfaces have been embedded in smartphones,which are a key contributor in acquiring context information and building smart mobile applications.Although the context retrieval cost on smartphone is significant,it is usually ignored by mobile application developers.This paper proposed a context retrieval cost model to analyze the cost of context information retrieval.We designed and implemented a context-retrieval-cost measuring tool,CRCTest,and measured the context retrieval cost model on an Android smartphone.Based on the measured cost model,we implemented an example application,and conducted some experiments to compare the cost of two approaches to acquiring location context.The result shows that it is feasible to optimize the context retrieval cost with the proposed context retrieval cost model.

Key words: Smartphone,Sensor,Context retrieval,Cost model