Wearable health monitoring systems have gained considerable interest in recent years owing to their tremendous promise for personal portable health watching and remote medical practices. The sensors with excellent flexibility and stretchability are crucial components that can provide health monitoring systems with the capability of continuously tracking physiological signals of human body without conspicuous uncomfortableness and invasiveness. The signals acquired by these sensors, such as body motion, heart rate, breath, skin temperature and metabolism parameter, are closely associated with personal health conditions. This review attempts to summarize the recent progress in flexible and stretchable sensors, concerning the detected health indicators, sensing mechanisms, functional materials, fabrication strategies, basic and desired features. The potential challenges and future perspectives of wearable health monitoring system are also briefly discussed.

This paper proposes a novel composite kernel for relation extraction. The composite kernel consists of two individual kernels: an entity kernel that allows for entity-related features and a convolution parse tree kernel that models syntactic information of relation examples. The motivation of our method is to fully utilize the nice properties of kernel methods to explore diverse knowledge for relation extraction. Our study illustrates that the composite kernel can effectively capture both flat and structured features without the need for extensive feature engineering, and can also easily scale to include more features. Evaluation on the ACE corpus shows that our method outperforms the previous best-reported methods and significantly outperforms previous two dependency tree kernels for relation extraction.

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We studied the background field for 60 two-ribbon flares of M-and-above classes during 2011-2015. These flares are categorized into two groups, i.e., eruptive and confined flares, based on whether a flare is associated with a coronal mass ejection or not. The background field of source active regions is approximated by a potential field extrapolated from the B z component of vector magnetograms provided by the Helioseismic and Magnetic Imager. We calculated the decay index n of the background field above the flaring polarity inversion line, and defined a critical height h crit corresponding to the theoretical threshold (n crit = 1.5) of the torus instability. We found that h crit is approximately half of the distance between the centroids of opposite polarities in active regions and that the distribution of h crit is bimodal: it is significantly higher for confined flares than for eruptive ones. The decay index increases monotonously with increasing height for 86% (84%) of the eruptive (confined) flares but displays a saddle-like profile for the rest, 14% (16%), which are found exclusively in active regions of multipolar field configuration. Moreover, n at the saddle bottom is significantly smaller in confined flares than that in eruptive ones. These results highlight the critical role of background field in regulating the eruptive behavior of two-ribbon flares.

Abstract-How to evaluate the image perceptual quality is a fundamental problem in image and video processing, and various methods have been proposed for image quality assessment (IQA). This letter presents a novel IQA metric, which is based on the image primitive features produced in the earliest processing stage of human visual system. The procedures involved in the proposed method include computing the response of classical receptive fields, zero-crossing detection, and non-shift edge based ratio (NSER) calculation. The proposed IQA metric is very simple but very effective. The experimental results on benchmark databases show that the NSER index has very high consistency with the psychological evaluation, performing much better than most state-of-the-art IQA metrics.Index Terms-Image quality assessment (IQA), non-shift edge (NSE), non-shift edge based ratio (NSER), zero-crossing.