合成孔径系统光束的大气传输

利用光束的合成孔径系统,通过控制子孔径系统发射光束的相位,可以实现光束的快速瞄准、跟踪及合成.本文在已开展的真空中合成孔径系统光束控制研究工作的基础上,进一步揭示了光束合成孔径系统可以有效地消除大气湍流对光束传输的影响,给出了数值模拟计算结果和三维图形演示.     

聚焦口径轴向电磁能的研究

对均匀振幅，凹冰面相位分布的圆口径天线和矩形口径天线的轴向辐射场进行研究、绘出了不同口径尺寸和焦距下的电磁能分布曲线。研究表明：电磁能可以聚焦在菲涅耳区或近区，口径增大时聚焦强度迅速提高，长距离的电磁能聚焦必须进行大口径天线的研究和应用。     

金属目标在聚焦天线焦平面上的散射

研究了目标在聚焦口径天线焦点的散射问题。以一个金属目标和一个理想口径组成的系统为例，阐明了这类散射问题的电磁过程。研究结果表明，选择适当的口径分布，可以大大提高目标回波强度。文中给出大量计算结果，并对不同的口径分布做了比较，得到了若干具有工程意义的重要结论。     

就近半城市化与去城市两级分化

农民以家庭为单位普遍选择的就近半城市化路径中,人口迁徙具有可逆性：一是从城市回流到农村的可逆性,二是从大城市回流到中小城市的可逆性。这两种可逆性勾勒着我国城市化进程中的“去城市两极分化”机制：类贫民窟作为物理载体仍然会在城市化的过程中存在,但在可逆过程中,它并不会形成一个刚性的城市社会贫民阶层,进而这种可逆性成为城市社会两极分化结构中的弹性要素;特大城市也会产生,但在可逆的过程中,作为纯资源接受者的中小城市将获得人口集聚和经济发展的契机,从而这种可逆性也构成了城市体系两极分化结构中的弹性要素。     

Measuring Social Tension from Income Class Segregation

We develop an index that effectively measures the level of social tension generated by income class segregation. We adopt the basic concepts of between-group difference (or alienation) and within-group similarity (or identification) from the income [bi]polarization literature; but we allow for asymmetric degrees of between-group antagonism in the alienation function, and construct a more effective identification function using both the relative degree of within-group clustering and the group size. To facilitate statistical inference, we derive the asymptotic distribution of the proposed measure using results from U-statistics. As the new measure is general enough to include existing income polarization indices as well as the Gini index as special cases, the asymptotic result can be readily applied to these popular indices. Evidence from the Panel Study of Income Dynamics data suggests that, while the level of social tension shows an upward trend over the sample period of 1981 to 2005, government’s taxes and transfers have been effective in reducing the level of social tension significantly.     

An Experiment on the Social Facilitation of Gambling Behavior

Research and theory regarding the social facilitation effect generates the expectation that the presence of other gamblers (or co-actors) in a gaming venue is likely to intensify individual gambling behavior and magnify losses. Fifty male and 66 female participants (116 total) played a computer-simulated electronic gaming machine with a fixed winning sequence, followed by an indefinite losing sequence. Measures of the intensity of gambling behavior included the final payout (a direct measure of losses), average bet-size, number of trials played, and the speed of play. Some participants received false feedback from the computer designed to suggest that other gamers in adjacent rooms were playing and sometimes winning at the same game. Persons who received both sight and sound information, including winning bells and instant messages regarding the wins of other (fake) players, placed more bets and lost more money compared to the other conditions with less information.     

社会工作两极化趋势及专业定位的反思

社会工作专业从产生之初就产生了两极化的趋势,即萌生于慈善组织会社的注重提供个人服务的取向和产生于睦邻组织的注重环境的改造及建立共同利益的取向。Spetch和Courtney在《背叛的天使》一书中批判了社会工作者心理治疗化的现象,认为社会工作者是背叛的天使,远离了自己的服务对象,背叛了社会工作的使命。本文通过回顾社会工作两极化产生的历史,分析社会工作心理治疗化的原因及限制,同时通过回顾中国大陆社会工作产生的背景,反思社会工作专业化的定位。     

热点公共事件群体极化：表征、影响及其应对

作为舆情异化的热点公共事件群体极化,具有蔓延负面情绪、筑设思维壁垒、滋生集体暴力等系列表征,呈现模糊核心议题、消解协商机制、扭曲良性意识、诱发公共危机等负面效应。究其因由,可溯源至信息泛滥作祟、公众心理失衡、社会撕裂激发、政民关系滑坡等不同维度。防范和化解热点公共事件群体极化,须从国家、社会、公民三重视域着手,多管齐下、规制导引,以净化舆论生态、凝聚社会共识。     

Child protection decision-making

The effects of interagency collaboration on risk assessment in child protection practice were analysed in respect of the decision-making processes in child death inquiries. Universal features in the assessment of risk as identified in psychological literature were applied; in particular, the concepts of ‘groupthink’, the ‘certainty effect’ and ‘group polarization’. It is suggested that case conference decisions are inherently more risky than those taken by professionals with individual responsibility because of the way in which cases are framed in terms of losses.     

Two-dimensional generalisations of dynamic programming for image analysis

Dynamic programming (DP) is a fast, elegant method for solving many one-dimensional optimisation problems but, unfortunately, most problems in image analysis, such as restoration and warping, are two-dimensional. We consider three generalisations of DP. The first is iterated dynamic programming (IDP), where DP is used to recursively solve each of a sequence of one-dimensional problems in turn, to find a local optimum. A second algorithm is an empirical, stochastic optimiser, which is implemented by adding progressively less noise to IDP. The final approach replaces DP by a more computationally intensive Forward-Backward Gibbs Sampler, and uses a simulated annealing cooling schedule. Results are compared with existing pixel-by-pixel methods of iterated conditional modes (ICM) and simulated annealing in two applications: to restore a synthetic aperture radar (SAR) image, and to warp a pulsed-field electrophoresis gel into alignment with a reference image. We find that IDP and its stochastic variant outperform the remaining algorithms.