Modelling of chromatic contrast for retrieval of wallpaper images

Colour remains one of the key factors in presenting an object and, consequently, has been widely applied in retrieval of images based on their visual contents. However, a colour appearance changes with the change of viewing surroundings, the phenomenon that has not been paid attention yet while performing colour‐based image retrieval. To comprehend this effect, in this article, a chromatic contrast model, CAMcc, is developed for the application of retrieval of colour intensive images, cementing the gap that most of existing colour models lack to fill by taking simultaneous colour contrast into account. Subsequently, the model is applied to the retrieval task on a collection of museum wallpapers of colour‐rich images. In comparison with current popular colour models including CIECAM02, HSI and RGB, with respect to both foreground and background colours, CAMcc appears to outperform the others with retrieved results being closer to query images. In addition, CAMcc focuses more on foreground colours, especially by maintaining the balance between both foreground and background colours, while the rest of existing models take on dominant colours that are perceived the most, usually background tones. Significantly, the contribution of the investigation lies in not only the improvement of the accuracy of colour‐based image retrieval but also the development of colour contrast model that warrants an important place in colour and computer vision theory, leading to deciphering the insight of this age‐old topic of chromatic contrast in colour science. © 2014 Wiley Periodicals, Inc. Col Res Appl, 40, 361–373, 2015     

道在山林，周弥六合——浙东天台山“洞天福地”的山岳景观流变及文化意象研究

道教洞天福地作为中国名山风景的经典类型之一，在宗教山岳景观中占据独特地位。浙东天台山水神秀，历代高道以入山隐修为主要目的，形成了道教在区域山林的景观文化基础。从天台山“神仙之乡”的文化背景出发，从“想象与实践”的视角切入，梳理了天台山洞天福地的景观流变：分析其“不死之福庭”地域性景观的形成经历了“赤城→桐柏”的信仰转移过程；以天台山为坐标，洞天福地格局打破了区域“层级”分布特征，而呈现大范围“州郡”空间格局。作为“联结点”的天台山，洞天世界沟通了宇宙、山、人3个基本场域，由此衍生出“洞宫”式和“周回”式山岳空间营建典范。旨在挖掘洞天福地中典型案例的价值，为中国洞天福地体系的构建提供理论依据。     

A Student's t-based density peaks clustering with superpixel segmentation (tDPCSS) method for image color clustering

Image color clustering is a basic technique in image processing and computer vision, which is often applied in image segmentation, color transfer, contrast enhancement, object detection, skin color capture, and so forth. Various clustering algorithms have been employed for image color clustering in recent years. However, most of the algorithms require a large amount of memory or a predetermined number of clusters. In addition, some of the existing algorithms are sensitive to the parameter configurations. In order to tackle the above problems, we propose an image color clustering method named Student's t-based density peaks clustering with superpixel segmentation (tDPCSS), which can automatically obtain clustering results, without requiring a large amount of memory, and is not dependent on the parameters of the algorithm or the number of clusters. In tDPCSS, superpixels are obtained based on automatic and constrained simple non-iterative clustering, to automatically decrease the image data volume. A Student's t kernel function and a cluster center selection method are adopted to eliminate the dependence of the density peak clustering on parameters and the number of clusters, respectively. The experiments undertaken in this study confirmed that the proposed approach outperforms k-means, fuzzy c-means, mean-shift clustering, and density peak clustering with superpixel segmentation in the accuracy of the cluster centers and the validity of the clustering results.     

Dietary advanced glycation end‐products: Perspectives linking food processing with health implications

Dietary advanced glycation end products (dAGEs) are complex and heterogeneous compounds derived from nonenzymatic glycation reactions during industrial processing and home cooking. There is mounting evidence showing that dAGEs are closely associated with various chronic diseases, where the absorbed dAGEs fuel the biological AGEs pool to exhibit noxious effects on human health. Currently, due to the uncertain bioavailability and rapid renal clearance of dAGEs, the relationship between dAGEs and biological AGEs remains debatable. In this review, we provide the most updated information on dAGEs including their generation in processed foods, analytical and characterization techniques, metabolic fates, interaction with AGE receptors, implications on human health and reducing strategies. Available evidence demonstrating a relevance between dAGEs and food allergy is also included. AGEs are ubiquitous in foods and their contents largely depend on the reactivity of carbonyl and amino groups, along with surrounding condition mainly pH and heating procedures. Once being digested and absorbed into the circulation, two separate pathways can be involved in the deleterious effects of dAGEs: an AGE receptor‐dependent way to stimulate cell signals, and an AGE receptor‐independent way to dysregulate proteins via forming complexes. Inhibition of AGEs formation during food processing and reduction in the diet are two potent approaches to restrict health‐hazardous dAGEs. To elucidate the biological role of dAGEs toward human health, the following significant perspectives are raised: molecular size and complexity of dAGEs; interactions between unabsorbed dAGEs and gut microbiota; and roles played by concomitant compounds in the heat‐processed foods.     

Hetero-assembly of colloidal particles in concentrated non-aqueous suspensions by polymer dispersant design

Although many colloidal assembling systems have been reported, most systems suffer from severe aggregation under high solid concentrations, which can often be observed in typical hetero-aggregation system. In this study, we created a hetero-assembly system using concentrated (~50 vol%) suspensions by mixing large SiO₂ particles modified with polyacrylic acid partially complexed with oleylamine (PAA-OAm) and small SiO₂ particles modified with polyethyleneimine partially complexed with oleic acid (PEI-OA) in a non-aqueous solvent. We demonstrated that hetero-assembly is driven by the interactions between the uncomplexed carboxyl/amine groups of the PAA/PEI present on the particles, while severe aggregation is simultaneously prevented by the steric repulsions of the aliphatic oleyl chains. Comparison of the cross sections of the in-situ solidified hetero-assembled suspensions with those of ideally assembled structures which were reproduced by a simulation considering the statistical distribution of particles strongly supported successful particle assembling via the proposed approach. The results revealed that the OA content in the PEI-OA complex was the dominant factor that controlled the dispersion and assembling state of the binary particles. The significance of this study is that our findings will provide a class of colloidal dispersion state which binary particles were assembled in a high solid content suspension without forming strong aggregates.     

靶面激光光斑尺寸原位测量的研究

提供了一种简便易行的靶面激光光斑尺寸原位测量的方法。从高斯光束的横向光强分布特性出发,建立了激光烧蚀斑半径与辐照激光能量、光斑尺寸、烧蚀阈值间的关系式,模拟分析发现辐照激光光斑尺寸对烧蚀斑半径随辐照能量变化曲线有较大影响。对于脉宽为2 ms,波长为1064 nm的激光,实验测量了不同能量激光辐照下相纸烧蚀斑半径,并用推导出的关系式拟合测量数据,获得了靶面处光斑尺寸和样品烧蚀阈值。同时,也测量了不同位置处的光斑尺寸和样品烧蚀阈值,对高斯光束束腰位置和样品烧蚀阈值的光斑尺寸效应进行了验证。研究结果表明该技术结果可靠,简单高效。该技术可以为高能激光与固体物质相互作用的基础研究和激光加工等应用领域中实现简单方便地测量靶面光斑尺寸提供帮助。     

中子平衡节块离散纵标法及CMFD加速技术研究

本文基于横向积分离散纵标方程,解析得到横向积分通量中出射通量与入射通量的关系,并根据类似于扩散方程节块展开法的输运节块中子平衡方程形式,得到了一种高效的节块离散纵标法数值迭代策略。数值结果表明,本文提出的方法可行且数值结果正确。此外,粗网有限差分(CMFD)加速技术在节块离散纵标法中也取得了非常好的应用效果。