带缓冲器的多入口、多出口串行生产线的无阻塞最优控制

本文讨论了带缓冲器的串行生产线的无阻塞最优控制问题,给出了多入口、多出口情况下串行生产线的加工状态方程及其最化控制。     

一类串行生产线的最优调度问题的注记

讨论了串行生产线的最优调度问题,给出了生产线生产周期的显示公式,给出两个变量时最优调度的解的特性．     

在公共与分离配置方式下具有缓冲区的生产线系统性能的比较

本文以极大代数理论为工具,针对生产率,比较了具有公共缓冲区的生产线系统及其对应的串行生产线系统,得到了前者的生产率比后者的生产率要高的结论．     

在公共与分离配置方式下具有缓冲区的生产线系统性能的比较

本文以极大代数理论为工具，针对生产率，比较了具有公共缓冲区的生产线系统及其对应的串行生产线系统，得到了前者的 生产率比后者的生产率要高的结论.     

多入口串行生产线的最优节奏控制

本文用极大代数讨论了在多入口情况下带存储器有阻塞串行生产线的最优节奏控制问题,给出了生产线的状态方程,批量生产的周期公式及其函数形式,最后用文〔1〕的算法对生产线进行节奏控制。     

对串行生产线极大代数方法建模的一点注记

本给出了多台机器串行生产线极大代数方法建模的一般方程的矩阵表示公式。     

多出口串行生产线系统矩阵的行列单调性

研究了极大代数意义下矩阵的行列单调性质，给出了带缓冲器的多出口串行生产线系统矩阵的行列单调性．     

保险公司的一般最优控制问题研究

在股票价格波动服从几何布朗运动规律的条件下,研究了保险公司的一般最优控制问题,得到了一般最优控制问题价值函数的HJB方程,利用鞅方法证明了HJB方程的识别定理,得到了一般最优控制问题中的最优策略。     

活性污泥法多变量最优控制的遗传算法实现

针对最优控制传统算法存在的一些问题,着重研究了采用遗传算法在限制有机物排放总量时,使污水处理运行费用最低的最优控制问题,提出了一种新的污水处理最优控制问题的计算方法,提高了计算效率.     

变动区域的稳定Navier-Stokes方程的形状最优控制

本文考虑了一族凸集上的稳定Navier-Stokes方程的最优控制问题,得到了稳定Navier-Stokes方程的最优控制的存在性.     

Materialism does not pay: Materialistic students have lower motivation,engagement, and achievement

The aim of this study was to examine how materialism, or the focus on acquiring money and material possessions, is associated with students’ academic engagement and achievement via their motivational regulation (amotivation, controlled motivation, and autonomous motivation). Study 1 (n = 606 secondary students) was a cross-sectional study which found that materialism was negatively associated with engagement. This association was partially mediated by amotivation. Study 2 (n = 404 secondary students) was a longitudinal study which found that Time 1 materialism was negatively associated with Time 2 engagement and Time 3 academic achievement via amotivation. Results of the two studies provide converging lines of evidence that materialism is negatively associated with key indicators of learning. Students with high levels of materialism have lower levels of engagement and achievement, and these associations are partially mediated by amotivation. Theoretical and practical implications are discussed.     

氢氘原子光谱实验最优参数的确定

为了获得了清晰的氢氘原子光谱谱线,首先确定了对光谱谱线有影响的负高压及狭缝宽度2个实验参量。先选定氢原子的一条谱线,在一定的负高压下,通过改变狭缝宽度来获取不同组光谱谱线,经分析得到理想的狭缝宽度范围。在该范围内选取几条狭缝宽度,分别通过改变负高压来得到理想的最优参数组。实验发现,对于不同的波长最优参数组参数不同,因此又用同样的方法对其他的谱线进行了探究,找到不同谱线的公共最优参数区间,最终获得了清晰的氢原子光谱谱线。     

Attributional retraining and elaborative learning: Improving academic development through writing-based interventions

Attributional retraining (AR) is a motivational intervention that consistently produces improved performance by encouraging controllable failure attributions. Research suggests that cognitively engaging AR methods are ideal for high-elaborating students, whereas affect-oriented techniques are better for low-elaborating students. College students' (N = 749) elaborative learning was assessed in the first semester, after which students were assigned to one of three writing-based AR conditions (No AR, Cognitive AR, Affective AR). Academic performance (course grades, GPA), motivation, attributions, and emotions were assessed in the second semester. AR by elaboration (low/high) 3 × 2 ANCOVAs showed optimal results for high elaborators following cognitive AR, and for low elaborators following affective AR. Performance improvements for the former were mediated by improved cognitions (expectations), and for the latter were mediated by increased positive affect.     

基于混合蚁群算法的“多日游”路线优化问题

针对＂多日游＂路线优化问题,提出了一种新的混合蚁群算法,并建立了＂多日游＂旅游交通路线的数学模型。通过多次实验和计算,证明将混合蚁群算法运用于＂多日游＂旅游交通线路,可以有效求得问题的最优解或近似最优解,并以秦皇岛地区各旅游景点为例进行了分析。     

A tunable dual-broad-band branch-line coupler utilizing composite right／left-handed transmission lines

INTRODUCTION Veselago (1968) theoretically analyzed the wave propagation in a left-handed (LH) material which has simultaneously a negative magnetic permeability and a negative electric permittivity. The electric field, the magnetic field, and the wave vector of an electro-magnetic wave propagating in such a material obey the left-hand rule (instead of the right-hand rule for usual materials). Such an LH material was first real-ized in 2001 in microwave region with an array of metallic …     

双-α-前不变凸函数的一些性质及应用

引入并研究双-α-前不变凸函数,双拟-α-前不变凸函数,双对数-α-前不变凸函数等新的广义凸函数,给出这些广义凸函数之间的关系,同时刻画双-α-前不变凸函数的一些性质。作为应用,证明双-α-前不变凸函数驻点与偏最优值点等价以及最大化问题的一个最优性条件。所得结果改进和推广了一些已有的成果。     

Morningness/eveningness and school performance among Spanish adolescents: Further evidence

Adolescents shift their time of day preferences from morning to evening during puberty when school schedule becomes earlier. Given that a better performance is obtained when individuals are tested at times that are in synchrony with their chronotype, and optimal sleep duration is positively associated with academic performance, evening-types may obtain worse school performance because of both morning school schedule and a decrease of total sleep time. A group of 1133 adolescents (aged 12–16) participated in this study. School performance was evaluated using subjective level of achievement and self-reported grades measures. Controlling for total sleep time, more evening oriented young adolescents (12–14 years) performed significantly worse in school achievement. Girls among 15–16 years performed significantly better than boys. These results have important implications for intervention and prevention programs during school years.     

Emotion regulation as a mediator of the relation between sexual abuse and behavior problems in preschoolers

Maltreated children show poor emotion regulation competencies compared to non-maltreated children. Emotion regulation has been found to mediate the association between maltreatment and behavior problems in children. The aim of the present study was to examine the relationships among child sexual abuse (CSA), emotion regulation (ER), and internalized and externalized behavior problems in preschoolers using conditional process analyses. ER competencies were assessed in 127 children aged 41–79 months (62 abused, 65 non-abused) by their parents (N = 124) and early childhood educators (N = 88) using the Emotion Regulation Checklist (Shields and Cicchetti, 1995, Shields and Cicchetti, 1997). Behavior problems were evaluated by parents using the Child Behavior Checklist (Achenbach and Rescorla, 2000, Achenbach and Rescorla, 2001). ER was found to completely mediate the relation between CSA and internalized behavior problems and partially mediate the relation between CSA and externalized behavior problems. Parents’ and educators’ evaluations of ER were also found to differ as a function of child gender. The discussion focuses on the relationships among CSA, ER, behavior problems, and child gender. The clinical implications of these findings are also examined. Promoting the optimal development of ER could prevent the emergence and exacerbation of behavior problems in these at-risk children and, in turn, foster resilience.     

Child sexual abuse research knowledge among child abuse professionals and laypersons

The purposes of this study were to: (1) Assess child abuse professionals’ and nonprofessionals’ knowledge of scientific research findings that are relevant to forensic child sexual abuse (CSA) evaluations and (2) describe associations between child abuse professionals’ levels of research knowledge and their education and experience. An 18-item multiple-choice test was administered to 188 child abuse professionals and 457 nonprofessionals (undergraduate college students) in Brazil and the United States. The nonprofessionals’ average percent correct, M = 44%, was not significantly different than what would be expected for random guessing (45%). The professionals’ average percent correct, M = 55%, was higher than that of nonprofessionals and random guessing (both ps < .001). The average percent correct score for the US-sample psychologists, M = 76%, was higher than the average score of the other professionals, M = 51%, p < .001. Professionals’ educational level, as measured by the highest academic degree obtained, was positively associated with percent correct scores, Spearman's ρ = .46, p < .001. Controlling for educational attainment, professional experience, as measured by the total number of CSA evaluations performed, was weakly associated with percent correct scores, partial r = .15, p = .04. Percent correct scores were low for both nonprofessionals and professionals. Most of the participants in this study were uninformed or misinformed about scientific research findings that are important for conducting optimal forensic CSA evaluations and for making accurate judgments about the validity of sexual abuse allegations.     

素描教学中的几点反思——对物体形和色关系的理解

立足于美术教学实践,着重讨论素描教学中出现的问题和不足,以物体的形和色之间的相互关系为话题,再来重新认识素描的基本观察、理解和表现的方法,从而加强对素描绘画中的整体意识、普遍联系的意识和变化发展的意识.牢固树立素描绝不单纯是打轮廓,绝不是仅由线条所组成的正确认识.素描它还具有独特的表现力,有内在的形式美.