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Density peaks clustering (DPC) is an efficient and effective algorithm due to its outstanding performance in discovering clusters with varying densities. However, the quality of this method is highly dependent on the cutoff distance. To improve the performance of DPC, the gravitation-based clustering (GDPC) algorithm is proposed. However, it cannot identify the clusters of varying densities. We developed a novel density peaks clustering algorithm based on the magnitude and direction of the resultant force acting on a data point (RFDPC). RFDPC is based on the idea that the resultant forces acting on the data points in the same cluster are more likely to point towards the cluster center. The cluster centers are selected based on the force directional factor and distance in the decision graph. Experimental results indicate superior performance of the proposed algorithm in detecting clusters of different densities, irregular shapes, and numbers of clusters.

Background We aimed to explore the association of serum level of the nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3 (NLRP3) and its related inflammatory biomarkers (hypoxia inducible factor-1α, cathepsin B, caspase-1 and matrix metalloproteinase-9) with malignant brain edema (MBE) in patients with acute ischemic stroke. Methods We prospectively enrolled patients with acute ischemic stroke admitted Results 200 patients (69.3 ± 14.3 years; male 55 %) were included for analysis, of whom 26 patients developed MBE (median time from stroke onset to MBE 32.5 h). Compared with patients without MBE, those with MBE had higher level of serum concentration of NLRP3 (median time from onset to blood collection 3 h, 1.85 ng/ml vs. 1.11 ng/ml, P = 0.026). NLRP3 level was positively correlated with NIHSS on admission (Spearman ρ = 0.18, P = 0.01) and the association between NLRP3 and MBE was attenuated (OR 1.47, 95 % CI 0.88–2.46, P = 0.138) after adjusting for age and NIHSS. There was no significant difference in other biomarkers between MBE and non-MBE groups. Conclusions There was a trend of association between a higher level of serum concentration of NLRP3 and an increased risk of MBE after ischemic stroke, possibly confounded by the severity of stroke, which is worth further validation in large cohort studies.

In recent decades, rock-filled concrete (RFC) has been widely adopted in the construction of massive concrete structures. RFC is similar to normal concrete materials and is commonly considered a composite material consisting of coarse rock aggregates, self-compacting concrete (SCC), and an interfacial layer in between. However, coarse aggregates larger than 300 mm in size normally occupy more than half the volume portion in RFC, forming a structural skeleton before the pouring of the SCC binder, and their interfaces with SCC may play a different role in the damage and fracture behavior as compared to that of the normal concrete. To investigate the mode-I fracture behavior of RFC along this type of interface, wedge splitting tensile (WST) tests were carried out in this study, and various influential factors were considered, including the SCC strength grade, rock surface roughness, and the purposeful covering of the interface by stone powder. Typical test results, including fracture loads, crack opening displacements, splitting failure characteristics, and their relationship with the considered factors were analyzed. Through comparison analyses, it was found that the surface fluctuation degree parameter shows the best positive correlation with the fracture properties from WST tests. Tension-softening curves (TSC) representing the interfacial cohesive behavior were determined, and a unified function was proposed for all test conditions. Following a comparative analysis of the strength and fracture properties from the interfaces of rock-SCC and those between rock and normal vibrated concrete, it was found that two ratio parameters (Rft and RGF) of the rock-SCC interface are approximately at the same level as those of the interface between rock and normal vibrated concrete.

Stereo matching is a challenging problem with respect to weak texture, discontinuities, illumination difference and occlusions. Therefore, a deep learning framework is presented in this paper, which focuses on the first and last stage of typical stereo methods: the matching cost computation and the disparity refinement. For matching cost computation, two patch-based network architectures are exploited to allow the trade-off between speed and accuracy, both of which leverage multi-size and multi-layer pooling unit with no strides to learn cross-scale feature representations. For disparity refinement, unlike traditional handcrafted refinement algorithms, we incorporate the initial optimal and sub-optimal disparity maps before outlier detection. Furthermore, diverse base learners are encouraged to focus on specific replacement tasks, corresponding to the smooth regions and details. Experiments on different datasets demonstrate the effectiveness of our approach, which is able to obtain sub-pixel accuracy and restore occlusions to a great extent. Specifically, our accurate framework attains near-peak accuracy both in non-occluded and occluded region and our fast framework achieves competitive performance against the fast algorithms on Middlebury benchmark.

At present, the concept of computational thinking is spreading in education circles around the world. From the point of view of current research and application in China, the research on the cultivation of computational thinking in K-12 education is still in the early stage. Based on the graphic programming design course of app inventor in primary and secondary schools, this study embeds computing thinking into teaching objectives and contents, constructs the teaching model of app inventor course with embedded computing thinking, and discusses how to cultivate students' computing thinking ability in teaching practice. The method provided in this paper is helpful to analyse the changes of students' computational thinking during the teaching process, and it can effectively identify teaching effects.

In the Open University the experiment teaching for computer specialty is an important link for the practice teaching. Constructing the laboratory the massive funds need be invested. Because there was limited experimental condition in many branch schools, they can provide all kinds of expensive computer experiment installation independently with difficulty. Under this kind of condition, use of simulation software was practice teaching important means. Constructing the distance laboratories made up tradition laboratory for branch school. According to Shanghai Open University existing computer specialized experiment teaching situation, we has carried on the reform and the exploration on the experiment teaching. The union among the traditional experiment in laboratory, the hypothesized experiment, and the distance experiment help us not only completing the experiment teaching plan but also solving open question of experiment teaching resources. Certainly it provided the help for the open learning and independent E-learning for the entire society.

Personalized recommendation is hot issue in information management system nowadays. With the technology, it can improve the QOS of information service. In this paper, we present a new user profile model based on semantic meta-model of digital resource, using implicit feedback, the users' profiles can be adjusted in time. Comparing the 'like' query in the standard SQL in relational databases, which can not decide the similarity according users' interests when keywords appear in several different fields, a novel similarity evaluation is given in algorithm of the personalized recommendation. Using the method, a personalized digital resources management system is developed, which can provide high quality information service, and it works well in practice.

There are many web-based curriculums in which the chapter navigation is designed as directory tree. In most cases, developing the directory tree requires a large quantity of code and the chapter navigation lacks flexibility as well as extensibility. In our method, we rationally integrated EXTJS with WEBWORK in the JAVA platform. The EXTJS code was directly introduced on the JSP page. The data required by EXTJS is generated by the programs and is transmitted into pages of JSP with the WEBWORK label of WW: PROPERTY. Afterwards, Jobs transforms JSP into SERVLET and sends HTML with static code and script file to client. Practical results show that the proposed method is more valid and feasible.