Research Institute of Applied Computing Technology, China Women’s University, Beijing, China

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Abstract—We find that there are serious problems in Cloud application development such as complex architecture and WS API, highly running cost, poor UI and interaction and so on, and that these problems stem from not fully utilized RIA’s (Rich Internet Application) advantages and inappropriate functionality segmentation between clientside and server-side. That is, Web services, application logic and transaction logic are overly concentrated on the server side; while on the client-side computing power has not been fully utilized. We propose a novel 2-Tier Cloud- ARchitecture (2TCAR), which contains RIA-based rich client tier and SimpleDB-based server-side Cloud tier. The rich client tier is maximized to implement most of functionalities of Cloud application and transaction logic; in contrast, the functionality in server-side Cloud tier is minimized to only implement data storage and query. The communication between these two tiers is also simplified via REST. In the article we researched corresponding technologies such as Cloud computing, Web services, REST, Flex in RIA and SimpleDB storage Cloud. In addition, we proposed how to use Flex to implement UI presentation & interaction, transaction logic, REST requests & responses in rich client tier; and we described how to design SimpleDB Cloud in server-side Cloud tier and communication between two tiers via REST. Last, a Cloud application system, which is called Cloud System of Electronic Health Records (EHR) for Orthodontics, is developed based on the research findings illustrated by the author in this paper. It has been shown that the 2TCAR is effective and valuable for Cloud application development.

Index Terms—2TCAR, Cloud Computing, EHR, Flex, EMR, RIA, SimpleDB

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Cite: Wenjun Zhang, "2-Tier Cloud Architecture and Application in Electronic Health Record," Journal of Software vol. 7, no. 4, pp. 765-772, 2012.