基于MYK-NTRUSign签名的用户认证方案

基于修复了延展性缺陷的NTRUSign算法，给出了一个使用智能卡的远程用户认证方案。该方案的安全性是基于单向Hash函数和在有限时间在大维数格计算最短向量的困难性。该方案包括4个阶段：注册阶段，登陆阶段，认证阶段和更改口令阶段。允许用户自主选择并更改口令，实现了双向认证；能够抵御中间人攻击，抗DoS攻击，具备前向安全性、强安全修复性和“黑名单”拒绝服务机制。是一个低开销、强安全性的方案。     

The malleability of age-related positive gaze preferences: Training to change gaze and mood.

Older adults show positive gaze preferences, but to what extent are these preferences malleable? Examining the plasticity of age-related gaze preferences may provide a window into their origins. We therefore designed an attentional training procedure to assess the degree to which we could shift gaze and gaze-related mood in both younger and older adults. Participants completed either a positive or negative dot-probe training. Before and after the attentional training, we obtained measures of fixations to negatively valenced images along with concurrent mood ratings. We found differential malleability of gaze and mood by age: for young adults, negative training resulted in fewer posttraining fixations to the most negative areas of the images, whereas positive training appeared more successful in changing older adults' fixation patterns. Young adults did not differ in their moods as a function of training, whereas older adults in the train negative group had the worst moods after training. Implications for the etiology of age-related positive gaze preferences are considered. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

橡胶细集料水泥砂浆基本性能研究

本文研究了橡胶细集料水泥砂浆的基本性能。试验表明橡胶细集料水泥砂浆的抗压强度及抗折强度明显受橡胶细集料掺量的影响。在橡胶细集料的掺量水平大于150kg/m3时,其28天立方抗压强度较普通砂浆降低30%或更多,抗折强度降低则超过20%。但同时发现该掺量水平下砂浆的应力应变特性与普通水泥砂浆相比存在显著不同,其抗折状态下极限拉应变可高达4600×10-6,极限轴压应变超过6000×10-6,凸现了其优越的变形能力,也预示着橡胶细集料水泥砂浆在能量吸收方面的潜力。试验中还发现橡胶细集料水泥砂浆的破坏模式与普通砂浆的脆性破坏模式相比较截然不同,表现出一定的延性破坏特征,由于橡胶细集料的掺入可以明显阻碍裂缝的开展,因此,橡胶细集料水泥砂浆试件能够经历反复加荷破坏过程而仍具有一定承载能力,表现出很高的延性。     

Stereotypes: Static Abstractions or Dynamic Knowledge Structures?

Stereotypes have been assumed to be long-lasting knowledge structures that persist even in the face of contrary evidence. However, there is almost no within-participant research relevant to this assumption. The authors describe 4 studies (N=267), the first 3 of which assessed within-participant stereotype stability over a few weeks with measures of stereotypic trait verification, typicality ratings of exemplar sets, and exemplar retrieval. In the 4th study, the authors manipulated context stability. Overall, results showed only low-to-moderate stereotype stability. The stability obtained was a function of the perceived centrality of traits or exemplars and of context constancy. The authors discuss the implications of these results for abstractionist, exemplar, mixed, and connectionist models and identify possible mechanisms that underlie within-participant stereotype instability. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Exploiting the malleability of gold for placer concentrate extraction and recovery

A novel, chemical-free method for extracting gold from gravity middlings is described. This method exploits the differences in relative malleability, rather than density, of gold and waste products by submitting concentrates to grinding in a rod mill. The grind products are separated through a sieve, where flattened gold particles are captured on the oversize while brittle waste reports to the fines. This paper presents the results of a field tour of this method throughout the Yukon placer gold fields, where gold was extracted from difficult to process stockpiled middlings. Recoveries were often well over 90%, with nearly pure raw gold effectively separated after only minutes of grinding in a batch mill. Gold remaining in the fine and evenly classified loss material is now more amenable to gravity processing than similarly sized unground concentrate. Further lab testing indicated that gold recoveries were most sensitive to the mill charge amount and total grind time. While these results are based on placer properties, the method has potential in any mill involving a gravity recovery circuit.     

Easier done than undone: Asymmetry in the malleability of implicit preferences.

Dual-process models imply that automatic attitudes should be less flexible than their self-reported counterparts; the relevant empirical record, however, is mixed. To advance the debate, the authors conducted 4 experiments investigating how readily automatic preferences for one imagined social group over another could be induced or reversed. Experiments 1 and 2 revealed that automatic preferences, like self-reported ones, could be readily induced by both abstract supposition and concrete learning. In contrast, Experiments 3 and 4 revealed that newly formed automatic preferences, unlike self-reported ones, could not be readily reversed by either abstract supposition or concrete learning. Thus, the relative inflexibility of implicit attitudes appears to entail, not immunity to sophisticated cognition, nor resistance to swift formation, but insensitivity to modification once formed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Great Expectations: "I'm Losing 25% of My Weight No Matter What You Say".

This study investigated whether informing obese individuals that they would lose only modest amounts of weight would lead them to adopt more realistic weight loss expectations. At a screening interview, 53 obese women reported that they expected to lose the equivalent of 28% of their initial weight during 1 year of treatment with the medication sibutramine. Prior to beginning treatment, participants were informed, both verbally and in writing, that they could expect to lose 5% to 15% of initial weight, the loss typically induced by current behavioral and pharmacologic approaches. This information, however, had little impact on their weight loss expectations when assessed on subsequent occasions. Results are discussed in terms of the origins, clinical significance, and potential malleability of obese individuals' weight loss expectations. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Controlling Malleability of Metamaterials through Programmable Memory

Malleability, the ability to adapt materials to specific shapes, is necessary in applications where a form closure is requested. The material should be easily deformable between desired stable shapes. Such stability can be obtained through bistable elements that act as memory in metamaterials. Herein, a material with memory behavior programmed by the local temperature is presented. The behavior can be switched between a permanent shape change and a complete elastic recovery after removing an applied mechanical load. Additionally, a deformed material can be forced to recover its shape by heating. Through an adaption of the mesostructure and the used polymers, the characteristic behavior (switching time and temperature) can be adjusted. Furthermore, heating can be applied locally that only certain parts are able to change. A unit cell design based on analytical and numerical analyses is demonstrated that considers not only the mesostructure but also the combination of polymeric materials with specific thermoresponsive mechanical behavior. Unit cells and structures of several cells are additively manufactured to validate the programmable behavior. The concept is extended to indirect heating with an alternating magnetic field, using a compound made from a polymeric material and magnetic particles.