Face recognition in smartphone has become an important utility in a smart city for ensuring security by law enforcement. It has various applications such as capturing real life events, tracking movement of a celebrity, detecting wanted criminals, searching for missing child, surveillance, etc. Involving smartphones to do this job is challenging. Low computation power and limited battery life are the major barriers behind completing this task in real time. Various methods have already been proposed to offload computation to cloudlet or cloud to increase efficiency. However, offloading doesn't always result in performance gain. Besides, challenges still lie in different cases such as sudden disconnection from cloudlets, involvement of multiple cloudlets, load balancing between cloudlets, prefetching data to cloudlets, etc. In this paper, we have proposed a dynamic architecture named SMARTLET that distributes tasks to cloudlets based on the runtime characteristics of the communication latencies and handles aforementioned challenges efficiently. We validated our architecture by running experiments on our testbed with several smartphones, cloudlets and AWS cloud. Results show that our proposed architecture gets around 3.1× performance gain over state-of-the-art face recognition in smartphone and 21% reduction in response time with respect to the best recent architecture for offloading face recognition to the cloud.

智能手机中的面部识别已成为智能城市中重要的工具，可通过执法来确保安全性。它具有各种应用程序，例如捕获现实生活中的事件，跟踪名人的动向，检测通缉的罪犯，寻找失踪的孩子，监视等等。使智能手机参与这项工作具有挑战性。低计算能力和有限的电池寿命是实时完成此任务的主要障碍。已经提出了各种方法来将计算卸载到小云或云上以提高效率。但是，卸载并不总是可以提高性能。此外，挑战仍然存在于不同的情况下，例如从小云突然断开连接，涉及多个小云，在小云之间进行负载平衡，将数据预取到小云等。在本文中，我们提出了一种名为SMARTLET的动态架构，该架构可根据通信等待时间的运行时特征将任务分配给cloudlet并有效地应对上述挑战。我们通过在带有多个智能手机，cloudlet和AWS云的测试平台上运行实验来验证我们的架构。结果表明，相对于将人脸识别卸载到云端的最新最佳架构，我们提出的架构比智能手机中最新的人脸识别性能提高了约3.1倍，响应时间减少了21％。我们通过在测试平台上使用多个智能手机，cloudlet和AWS云运行实验来验证我们的架构。结果表明，相对于将人脸识别卸载到云端的最新最佳架构，我们提出的架构比智能手机中最新的人脸识别性能提高了约3.1倍，响应时间减少了21％。我们通过在带有多个智能手机，cloudlet和AWS云的测试平台上运行实验来验证我们的架构。结果表明，相对于将人脸识别卸载到云端的最新最佳架构，我们提出的架构比智能手机中最新的人脸识别性能提高了约3.1倍，响应时间减少了21％。