Bio-Inspired Small Target Motion Detection With Spatio-Temporal Feedback in Natural Scenes.

Small moving objects at far distance always occupy only one or a few pixels in image and exhibit extremely limited visual features, which bring great challenges to motion detection. Highly evolved visual systems endow flying insects with remarkable ability to pursue tiny mates and prey, providing a good template to develop image processing method for small target motion detection. The insects' excellent sensitivity to small moving objects is believed to come from a class of specific neurons called small target motion detectors (STMDs). However, existing STMD-based methods often experience performance degradation when coping with complex natural scenes. In this paper, we propose a bio-inspired visual system with spatio-temporal feedback mechanism (called Spatio-Temporal Feedback STMD) to suppress false positive background movement while enhancing system responses to small targets. Specifically, the proposed visual system is composed of two complementary subnetworks and a feedback loop. The first subnetwork is designed to extract spatial and temporal movement patterns of cluttered background by neuronal ensemble coding. The second subnetwork is developed to capture small target motion information where its output and signal from the first subnetwork are integrated together via the feedback loop to filter out background false positives in a recurrent manner. Experimental results demonstrate that the proposed spatio-temporal feedback visual system is more competitive than existing methods in discriminating small moving targets from complex natural environments.

Model-free kinematic control of redundant manipulators with simultaneous joint-physical-limit and joint-angular-drift handling.

Model-free tracking control methods have been developed for redundant robotic manipulators with unknown kinematic or dynamic models. However, most existing works have not considered the problems of joint physical limits and joint angular drift. Joint angular drift refers to the phenomenon that the joint angles of a redundant manipulator are different from their initial state when the end-effector of the manipulator returns to its initial position. Therefore, this article proposes a model-free scheme for the tracking control of redundant manipulators as well as the avoidance of joint physical limits and joint angular drift. The proposed method aims to overcome these challenges by formulating the inverse kinematics problem as a constrained optimization problem, which incorporates the avoidance of joint angular drift into the optimization objective and takes the joint physical limits as a constraint. At the same time, an online Jacobian estimator is designed to observe the state of the manipulator. Specifically, it can estimate the Jacobian matrix of a redundant manipulator in real-time during the operation by fully exploiting the sensory data, without knowing the analytic robot model. Then, the optimization problem is integrated with the Jacobian estimator and solved by a discrete-time algorithm. Theoretical analysis is conducted to prove the stability and convergence of the proposed method. Moreover, the efficacy, practicability and superiority of the proposed method are supported by simulations and experiments based on different redundant manipulators.

Electroacupuncture for the treatment of perimenopausal syndrome: a systematic review and meta-analysis of randomized controlled trials.

OBJECTIVE: To assess the efficacy, comparative effectiveness and safety of electroacupuncture (EA) in the treatment of perimenopausal syndrome (PMS). METHODS: Nine databases were searched until June 2019. Only relevant randomized controlled trials (RCTs) of EA for PMS were included. RESULTS: Twelve trials involving 746 women were included. EA and hormone therapy (HT) did not significantly differ in terms of effective rate (risk ratio (RR) = 0.98, 95% confidence interval (CI) = 0.93 to 1.04), Kupperman index (KI) (mean difference (MD) = -0.25, 95% CI = -0.76 to 0.26) and serum levels of follicle-stimulating hormone (FSH) (MD = -3.80, 95% CI = -11.59 to 3.98) or luteinizing hormone (LH) (MD = -2.51, 95% CI = -10.72 to 5.70). Serum estradiol (E2) levels were significantly lower in EA versus HT groups (MD = -60.58, 95% CI = -71.93 to -49.23). Compared with sham EA, EA had a significantly greater effect on reductions in KI (MD = -4.71, 95% CI = -6.57 to -2.86) and hot flushes score/24 h (MD = -2.43, 95% CI = -2.93 to -1.93). There were no significant differences between EA and manual acupuncture (MA) in terms of effective rate (RR = 1.14, 95% CI = 0.98 to 1.33) or serum FSH (MD = -2.87, 95% CI = -29.65 to 23.91), LH (MD = 2.73, 95% CI = -9.65 to 15.11) or E2 (MD = 26.80, 95% CI = -12.06 to 65.65). However, it seemed that EA had a better effect than MA on KI (MD = -2.44, 95% CI = -4.80 to -0.08). Subgroup analyses indicated that EA may have more of a benefit in the pre-menopausal state (hot flushes score/24 h: MD = -1.66, 95% CI = -3.49 to 0.17) compared to post-menopause (p > 0.05). CONCLUSION: The effect of EA appeared broadly similar to HT and MA in the treatment of PMS, although EA-associated reductions in KI were superior to MA and sham EA, suggesting effects beyond placebo. The evidence base is limited by a small number of eligible studies, risk of bias and clinical/statistical heterogeneity, limiting our ability to draw firm conclusions. As such, additional larger scale, high-quality RCTs are needed.

Weighted Matrix Decomposition for Small Surface Defect Detection.

Detecting small defects against a complex surface is highly challenging but crucial to ensure product quality in industry sectors. However, in the detection performance of existing methods, there remains a huge gap in the localization and segmentation of small defects with limited sizes and extremely weak feature representation. To address the above issue, this paper presents a weighted matrix decomposition model (WMD) for small defect detection against a complex surface. Firstly, a weighted matrix is constructed based on texture characteristics of RGB channels in the defect image, which aims to improve contrast between defects and the background. Based on the sparse and low-rank characteristics of small defects, the weighted matrix is then decomposed into low-rank and sparse matrices corresponding to the redundant background and defect areas, respectively. Finally, an automatic threshold segmentation method is used to obtain the optimal threshold and accurately segment the defect areas and their edges in the sparse matrix. The experimental results show that the proposed model outperforms state-of-the-art methods under various quantitative evaluation metrics and has broad industrial application prospects.

Electroacupuncture facilitates implantation by enhancing endometrial angiogenesis in a rat model of ovarian hyperstimulation.

Controlled ovarian hyperstimulation (COH) impairs the synchronized development of endometrium and embryo, resulting in the failure of embryo implantation. Here, we investigated what effects electroacupuncture had on embryo implantation in COH rats. Female rats were randomly assigned to four groups: normal (N), model (M), electroacupuncture (EA), and electroacupuncture pretreatment (PEA). Rats in groups M, EA, PEA were injected with pregnant mare serum gonadotropin (PMSG) and human chorionic gonadotropin to establish the COH model. Rats in group EA received electroacupuncture treatment from the PMSG injection day to the 3rd day of pregnancy (D3), while those in group PEA received electroacupuncture treatment for 3 days before the PMSG day and continuing to D3. Furthermore, another 30 female rats who received the same treatment as the rats in group PEA were injected with siVEGFR2 into uterine lumen. The endometrial microvascular density (MVD) and the expression levels of vascular endothelial growth factor-A, angiopoietin-1, and fibroblast growth factor-2 were significantly lower in groups M than in groups N and PEA. The percentage of dolichos biflorus agglutinin positive uterine natural killer cells in groups N, EA and PEA was higher than that in group M. After the siVEGFR2 injection, the protein expression levels of vascular endothelial growth factor receptor 2 (VEGFR2), PI3K, p-AKT and p-ERK, the embryo number and the MVD were significantly reduced. In conclusion, electroacupuncture can facilitate embryo implantation in COH rats by activating the VEGFR2/PI3K/AKT and VEGFR2/ERK signaling pathways which have a positive relationship with endometrial angiogenesis.

Effect of Acupuncture on Endometrial Angiogenesis and Uterus Dendritic Cells in COH Rats during Peri-Implantation Period.

This study was to explore the mechanism of acupuncture on regulating the endometrial angiogenesis and uterus dendritic cells (uDCs) during the peri-implantation period. Rats, in early pregnancy, were randomized into five groups: normal (N), model (M), acupuncture (A), progesterone (P), and A + P groups. The COH model was established using pregnant mare serum, combined with human chorionic gonadotrophin. Endometrium was collected on days 4, 6, and 8 (D4, D6, and D8) of gestation. Compared with group M, both VEGF and FGF-2 protein and mRNA levels were significantly lower on D4 and higher on D6 and D8 (P < 0.05), except for VEGF of group P on D8; the proportion of uterus dendritic cells (uDCs) in the endometrium was significantly lower on D4 and D6 and higher on D8 (P < 0.05). In vitro, except for the proliferation of group P on D8, proliferation, tube formation, and migration of uDCs were significantly decreased on D4 and increased on D8 (P < 0.05). In addition, acupuncture or progesterone regulated the secretion levels of VEGF, IL-15, and IL-18 secreted by uDCs instead of soluble sFLT-1. In conclusion, acupuncture may regulate angiogenesis of the endometrium and the number and roles of uDCs after COH, and the specific mechanism may be different with progesterone.