Object detection on drone images with low-latency is an important but challenging task on the resource-constrained unmanned aerial vehicle (UAV) platform. This paper investigates optimizing the detection head based on the sparse convolution, which proves effective in balancing the accuracy and efficiency. Nevertheless, it suffers from inadequate integration of contextual information of tiny objects as well as clumsy control of the mask ratio in the presence of foreground with varying scales. To address the issues above, we propose a novel global context-enhanced adaptive sparse convolutional network (CEASC). It first develops a context-enhanced group normalization (CE-GN) layer, by replacing the statistics based on sparsely sampled features with the global contextual ones, and then designs an adaptive multi-layer masking strategy to generate optimal mask ratios at distinct scales for compact foreground coverage, promoting both the accuracy and efficiency. Extensive experimental results on two major benchmarks, i.e. VisDrone and UAVDT, demonstrate that CEASC remarkably reduces the GFLOPs and accelerates the inference procedure when plugging into the typical state-of-the-art detection frameworks (e.g. RetinaNet and GFL V1) with competitive performance. Code is available at https://github.com/Cuogeihong/CEASC.

Mobile web usage has significantly increased in last few years. There has been a lot of emphasis on providing good web page performance for mobile devices. Client-side caching can play a significant role in providing good web page performance, but unfortunately, traditional browser caches lack in various aspects leading to sub-optimal performance. More specifically, web applications do not have control on caching, e.g., which resources to cache, how to cache, etc., leading to ineffective cache utilization. Recently, HTML5 has introduced number of persistent storage APIs, that can provide required control for web applications. We evaluate these HTML5 storage options on various devices, and find that they can also meet the performance criteria of caching; in fact, some of the HTML5 storage APIs, e.g., localStorage, can provide even better performance than browser cache. Based on these insights, we make a case for application-managed hierarchical client-side cache, called HCache, that leverages these storage options as backends. We propose a novel API that allows web application developers to intelligently control the caching behavior and the usage of these storage options transparently. Our experiments with a prototype show that HCache can improve web page performance by up to 60%.

Wikis have proven to be a valuable tool for collaboration and content generation on the web. Simple semantics and ease-of-use make wiki systems well suited for meeting many emerging region needs in the areas of education, collaboration and local content generation. Despite their usefulness, current wiki software does not work well in the network environments found in emerging regions. For example, it is common to have long-lasting network partitions due to cost, power and poor connectivity. Network partitions make a traditional centralized wiki architecture unusable due to the unavailability of the central server. Existing solutions towards addressing connectivity problems include web-caching proxies and snapshot distribution. While proxies and snapshots allow wiki data to be read while disconnected, they prevent users from contributing updates back to the wiki.

In this paper we present an analysis of HTTP traffic captured from Internet cafés and kiosks from two different developing countries -- Cambodia and Ghana. This paper has two main contributions. The first contribution is a analysis of the characteristics of the web trace, including the distribution and classification of the web objects requested by the users. We outline notable features of the data set which effect the performance of the web for users in developing regions. Using the trace data, we also perform several simulation analyses of cache performance, including both traditional caching and more novel off-line caching proposals. The second contribution is a set of suggestions on mechanisms to improve the user experience of the web in these regions. These mechanisms include both applications of well-known research techniques as well as offering some less well-studied suggestions based on intermittent connectivity.