基于用户访问模式的WWW浏览路径优化

分析了WWW用户的浏览活动规律,提出了有关WWW浏览路径优化的一些基本概念,设计了一个基于用户访问模式的浏览路径优化算法,并与相关的工作进行了比较.     

Ranked linear models and sequential patterns recognition

Ranked models in the form of linear transformations of multivariate feature vectors on a line can be found on the basis of a priori given order within particular pairs of objects or events. Such ranked transformations are designed to preserve given sequential order. In this way, the sequential patterns inside sets of the feature vectors can be discovered and modelled. Attention is paid here to combining problems of sequential patterns modelling and recognition with feature selection. The feature selection problem is aimed at the best representation of the sequential patterns. The convex and piecewise linear (CPL) criterion functions are used here both for designing ranked linear models and for feature selection.

Evolving Object-Oriented Designs with Refactorings

Refactorings are behavior-preserving program transformations that automate design evolution in object-oriented applications. Three kinds of design evolution are: schema transformations, design pattern microarchitectures, and the hot-spot-driven-approach. This research shows that all three are automatable with refactorings. A comprehensive list of refactorings for design evolution is provided and an analysis of supported schema transformations, design patterns, and hot-spot meta patterns is presented. Further, we evaluate whether refactoring technology can be transferred to the mainstream by restructuring non-trivial C++ applications. The applications that we examine were evolved manually by software engineers. We show that an equivalent evolution could be reproduced significantly faster and cheaper by applying a handful of general-purpose refactorings. In one application, over 14K lines of code were transformed automatically that otherwise would have been coded by hand. Our experiments identify benefits, limitations, and topics of further research related to the transfer of refactoring technology to a production environment.     

Stress Induced Color and Pattern for Information Coding

On the process of deforming polymer, its morphologies can be vividly observed and reflected via the internal stress distribution under the polarized light due to its special stretched birefringence, which gives a new way to store and read information. Inspired by this vivid character, a novel crosslinked polyurethane (PU) is designed and used as matrix for coding information, in which aluminum acetylacetonate works as the crosslinker to form dynamical crosslinked structure with coordinated bonds. By tailoring these two bonds via a region-selective regulation, the information can be written in the crosslinked PU. Only under the polarized light, the coded information can be read as stress induced color on the deformed state. After its recovery, 2D pattern can be simultaneously formed on the surface of the film. Therefore, the information is expressed in multiple channels. Thanks to the dynamic character, the information can be also erased and rewritten. Therefore, it is a new method for information coding with a high security, which has a wide range of potential applications in data storage, anticounterfeiting labeling, information conversion, and other areas.     

Laser Structuring of Thin Metal Films of Compliant Electrodes on Dielectric Elastomers

Dielectric elastomer (DE) transducers are polymer-based devices consisting of an insulating elastomeric membrane with compliant electrodes on both sides, forming a flexible capacitor that can work as an actuator or sensor. In this report, a new direct and maskless method is presented to pattern-compliant metallic electrodes specially developed for DE applications. Highly conductive and stretchable nickel-based electrodes are first sputter deposited onto pre-stretched membranes, resulting in a wrinkled surface after relaxation. An arbitrary electrode design is directly patterned onto the double-sided coated DE membrane by means of an ultra-short pulse laser system with a wavelength of 355 nm. In this way, it is possible to achieve simultaneous ablation of both electrodes on the top and the bottom side of the silicone membrane, as well as a selective ablation of only the electrode facing the laser. With a minimal optical resolution of 20 µm, the laser structuring method opens the path toward the manufacturing of miniaturized DE transducers, such as micro-scale DE arrays with integrated conductive paths, as well as the integration of optical features like diffraction gratings into the DE electrodes.     

Patterns of students' collaborations by variations in their learning orientations in blended course designs: How is it associated with academic achievement?

Background

While a number of learner factors have been identified to impact students' collaborative learning, there has been little systematic research into how patterns of students' collaborative learning may differ by their learning orientations.

Objectives

This study aimed to investigate: (1) variations in students' learning orientations by their conceptions, approaches, and perceptions; (2) the patterns of students' collaborations by variations in their learning orientations and (3) the contribution of patterns of collaborations to academic achievement.

Methods

A cohort of 174 Chinese undergraduates in a blended engineering course were surveyed for their conceptions of learning, approaches to learning and to using online learning technologies, and perceptions of e-learning, to identify variations in their learning orientations. Students' collaborations and mode of collaborations were collected through an open-ended social network analysis (SNA) questionnaire.

Results and Conclusions

A hierarchical cluster analysis identified an ‘understanding’ and ‘reproducing’ learning orientations. Based on students' learning orientations and their choices to collaborate, students were categorized into three mutually exclusive collaborative group, namely Understanding Collaborative group, Reproducing Collaborative group and Mixed Collaborative group. SNA centrality measures demonstrated that students in the Understanding Collaborative group had more collaborations and stayed in a better position in terms of capacity to gather information. Both students' approaches to learning and students' average collaborations significantly contributed to their academic achievement, explaining 3% and 4% of variance in their academic achievement respectively. The results suggest that fostering a desirable learning orientation may help improve students' collaborative learning.     

Proposals for producing novel periodic structures by ion bombardment sputtering

It is proposed, and confirmed analytically that if multiple ion fluxes are incident simultaneously, all at the same oblique polar angle but at different azimuthal angles, on to a target then the individual ripple patterns generated by sputtering are superimposed to produce novel surface structures. It is also shown that single focused ion fluxes incident on to rotating targets can produce circular ripple patterns.     

Social Identity, Group Processes, and Performance in Synchronous Computer-Mediated Communication.

This study examined group processes in a synchronous context and their effects on performance, assuming that these processes would be strongly dependent on the salience of social identity. It was predicted that the mere categorization of students into an online group and comparison with other groups, 2 basic conditions related to social identity, would enhance group identification, interaction patterns, and group performance in a relatively complex academic task. As predicted, the categorization manipulation enhanced group identification and increased task- and morale-building communication. It was not related to performance. These findings invite a more thorough examination of the impact of social identity on the building of a sense of online community at the early stage of a learning process. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Detection of Grouped and Ungrouped Parts in Visual Patterns by Tufted Capuchin Monkeys (Cebus apella) and Humans (Homo sapiens).

The authors investigated perceptual grouping in capuchin monkeys (Cebus apella) and humans (Homo sapiens). In Experiment 1, 6 monkeys received a visual pattern as the sample and had to identify the comparison stimulus featuring some of its parts. Performance was better for ungrouped parts than for grouped parts. In Experiment 2, the sample featured the parts, and the comparison stimuli, the complex figures: The advantage for ungrouped elements disappeared. In Experiment 3, in which new stimuli were introduced, the results of the previous experiments were replicated. In Experiment 4, 128 humans were presented with the same tasks and stimuli used with monkeys. Their accuracy was higher for grouped parts. Results suggest that human and nonhuman primates use different modes of analyzing multicomponent patterns. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

清代家具工艺特点浅析

清代家具具有自己鲜明的特点,尤其是在其制作工艺方面,除了继承明代的淳朴特征之外,还表现出稳重华丽的一面。本文分析了清代家具的总体的特征,并从雕饰图案的提炼分析和用材的美学特性这两个细节作了更进一步的阐述。在对清代家具的这些工艺特点分析中,我们可以窥视到清代文化的另外组成部分,对研究中华文化的发展和演变提供了另一方面的资料。