An elitist non-dominated sorting genetic algorithm enhanced with a neural network applied to the multi-objective optimization of a polysiloxane synthesis process

This paper presents an original software implementation of the elitist non-dominated sorting genetic algorithm (NSGA-II) applied and adapted to the multi-objective optimization of a polysiloxane synthesis process. An optimized feed-forward neural network, modeling the variation in time of the main parameters of the process, was used to calculate the vectorial objective function of NSGA-II, as an enhancement to the multi-objective optimization procedure. An original technique was utilized in order to find the most appropriate parameters for maximizing the performance of NSGA-II. The algorithm provided the optimum reaction conditions (reaction temperature, reaction time, amount of catalyst, and amount of co-catalyst), which maximize the reaction conversion and minimize the difference between the obtained viscometric molecular weight and the desired molecular weight. The algorithm has proven to be able to find the entire non-dominated Pareto front and to quickly evolve optimal solutions as an acceptable compromise between objectives competing with each other. The use of the neural network makes it also suitable to the multi-objective optimization of processes for which the amount of knowledge is limited.     

Effective spacetime from multidimensional gravity

We study the effective spacetimes in lower dimensions that can be extracted from a multidimensional generalization of the Schwarzschild-Tangherlini spacetimes derived by Fadeev, Ivashchuk, and Melnikov (Phys. Lett. A 161, 98 (1991)). The higher-dimensional spacetime has D = (4 + n + m) dimensions, where n and m are the number of “internal” and “external” extra dimensions, respectively. We analyze the effective (4 + n) spacetime obtained after dimensional reduction of the m external dimensions. We find that when the m extra dimensions are compact (i) the physics in lower dimensions is independent of m and the character of singularities in higher dimensions, and (ii) the total gravitational mass M of the effective matter distribution is less than the Schwarzschild mass. In contrast, when the m extra dimensions are large, this is not so; the physics in (4 + n) does explicitly depend on m as well as on the nature of singularities in high dimensions, and the mass of the effective matter distribution (with the exception of wormhole-like distributions) is larger than the Schwarzschild mass. These results may be relevant to observations for an experimental/observational test of the theory.     

Improving peer-to-peer search performance through intelligent social search

As a large amount of information is added onto the Internet on a daily basis, the efficiency of peer-to-peer (P2P) search has become increasingly important. However, how to quickly discover the right resource in a large-scale P2P network without generating too much network traffic remains highly challenging. In this paper, we propose a novel P2P search method, by applying the concept of social grouping and intelligent social search; we derive peers into social groups in a P2P network to improve search performance. Through a super-peer-based architecture, we establish and maintain virtual social groups on top of a P2P network. The interactions between the peers in the P2P network are used to incrementally build the social relationships between the peers in the associated social groups. In such a P2P network, a search query is propagated along the social groups in the overlay social network. Our preliminary experiments have demonstrated that our method can significantly shorten search routes and result in a higher peer search performance. In addition, our method also enhances the trustworthiness of search results because searches go through trusted peers.     

Motivation of Engineering Students to Participate in Teaching Evaluations

This study employs expectancy theory to evaluate some key factors that motivate students to participate in the teaching evaluation process. The results show that engineering students generally consider the improvement of teaching to be the most important outcome of teaching evaluations, followed by the improvement of course content and format. Making the results of evaluations available for students' decisions on course and instructor selection ranked third, while the least important use was influencing a professor's tenure, promotion, and salary raise. Students' motivation to participate in teaching evaluations is also impacted significantly by their expectation that they will be able to provide meaningful feedback.     

Exploratory play as an index of mastery motivation: Relationships to persistence, cognitive functioning, and environmental measures.

To measure exploratory play at 1 yr of age, 41 middle-class infants were observed in a free-play setting. In a separate session, 11 structured tasks assessed the infants' persistence in mastering tasks. In a 3rd session, the Bayley Scales of Infant Development were given. As part of another study, home observations were available for 40 of the infants at 1 yr of age and for 23 of the infants at 6 mo of age. Measures of quantitative aspects of exploratory play showed no relationship to persistence or cognitive development; however, measures indexing the quality of exploratory play did. In addition, environmental measures at both 6 and 12 mo were related to exploratory play at 1 yr, particularly to the production of perceptual effects; but some of these findings were opposite to those expected. Results suggest that the quality of exploratory play, rather than the quantity, is a better index of underlying mastery motivation. In addition, the widely accepted assumption of a link between the amount of general exploration and cognitive ability needs to be reexamined. (27 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A field comparison of neck and shoulder postures in symptomatic and asymptomatic office workers

Poor neck and shoulder postures have been suggested to be a cause of neck and shoulder pain in computer workers. The present study aimed to evaluate and compare the head, neck and shoulder postures of office workers with and without symptoms in these regions, in their actual work environments. The two all female subject groups reported significantly different discomfort scores across five trials repeated in a single working day. The results of repeated video capture and two-dimensional motion analysis showed that there were trends for increased head tilt and neck flexion postures in the symptomatic subjects (n = 8), compared to the asymptomatic subjects (n = 8). Symptomatic subjects also tended to have more protracted acromions compared with asymptomatic subjects and showed greater movement excursions in the head segment and the acromion. All subjects demonstrated an approximately 10% increase in forward head posture from their relaxed sitting postures when working with the computer display, but there were no significant changes in posture as a result of time-at-work.     

改进缺陷,套刻和聚焦性能的第五世代浸没式曝光系统

论述了第五世代双扫描平台浸液式扫描曝光机的性能和进展。表明了在高速扫描状态下有生产价值的套刻和聚焦性能的实现。浸液式设备更多的关键部分与缺陷有关,而且该机的改进是通过有生产价值的缺陷水平方面来体现的。为了保持这种缺陷水平的改进效果,需要在圆片应用中进行专门稳定的测量。特加是边缘空泡除去(EBR)设计和圆片斜面良流线性是很重要的。     

Optical properties of γ-irradiated synthetic sapphire and yttria-stabilized zirconia spectroscopic windows

Synthetic sapphire and yttria-stabilized zirconia single-crystals were irradiated by increasing doses of γ-radiation to study the changes of their optical properties. The optical transparency of -Al₂O₃ was nearly constant up to the γ-radiation dose of 150 kGy for the spectral range of 400–1000 nm, while yellowish-brown coloration of (Zr_0.89Y_0.11)O_1.94 appeared for irradiation above 1 kGy. However, after a short-term heating in the temperature of 210^oC stable discoloration of zirconia can be achieved.