连续时间系统的目标轨迹预见跟踪控制

针对连续系统的有限时间目标轨迹预见跟踪控制问题,给出了基于轨迹协调误差和切换规则的预见跟踪控制方法.该方法首先将轨迹协调误差和位置跟踪误差连同状态变量的微分组成新的系统状态变量,把跟踪问题转化为调节问题,设计了基于协调误差的带有目标值预见的跟踪控制系统.然后针对复杂目标轨迹跨过不同坐标轴的情况,采用切换系统方法,实现了目标轨迹的全程预见跟踪控制.本文同时是子系统为时变系统的切换系统的典型范例.数值仿真说明了该方法的有效性.     

Early identification of reading difficulties using heterogeneous developmental trajectories.

Serious conceptual and procedural problems associated with current diagnostic methods call for alternative approaches to assessing and diagnosing students with reading problems. This study presents a new analytic model to improve the classification and prediction of children's reading development. Growth mixture modeling was used to identify the presence of 10 different heterogeneous developmental patterns. In all, 411 children in kindergarten through Grade 2 from 3 elementary schools in Texas were administered measures of phonological awareness, word recognition, and rapid naming skills 4 times a year. The mean ages were 5.8 years (SD = 0.35) for the kindergartners, 6.9 years (SD = 0.39) for Grade 1, and 8.0 years (SD = 0.43) for Grade 2; the percentage of boys was 50%. The results indicate that precursor reading skills such as phonological awareness and rapid naming are highly predictive of word reading (word recognition) and that developmental profiles formed in kindergarten are directly associated with development in Grades 1 and 2. Students identified as having reading-related difficulties in kindergarten exhibited slower development of word recognition skills in subsequent years of the study. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Reduction of motion artifacts in cine MRI using variable-density spiral trajectories

This study proposed to demonstrate a classically conditioned blood sugar decrease in humans and to clarify its relevance for binge eating. Six conditioning trials were run in healthy females. The conditioned stimulus (CS) was a compound peppermint flavor/fragrance, whereas the unconditioned stimulus (UCS) consisted of 50 g of oral glucose. Control subjects received an aspartame drink as the UCS. Ad lib glucose intake, blood parameters, and subjective craving were monitored before and after conditioning. Results showed that the experimental group failed to show conditioned blood sugar and glucagon decreases or C-Peptide increases. Although an increased insulin response was found in the experimental group, the effect size did not exceed that of spontaneous fluctuations. No increases in craving for sweet substances were found. An impressive increase (mean: 78%) in glucose intake after conditioning was found in both conditions, as well as in a subsequently run third condition with plain water as the UCS. The increased glucose intake probably resulted from an initial neophobia to the laboratory setting that subsided as subjects had experienced more lab sessions. Importantly, because no conditioned hypoglycemia occurred in the present study, its relationship with subjectively experienced craving for sweet substance could not be determined.     

Guilt and effortful control: Two mechanisms that prevent disruptive developmental trajectories.

Children’s guilt associated with transgressions and their capacity for effortful control are both powerful forces that inhibit disruptive conduct. The authors examined how guilt and effortful control, repeatedly observed from toddlerhood to preschool age, jointly predicted children’s disruptive outcomes in 2 multimethod, multitrait longitudinal studies (Ns = 57 and 99). Disruptive outcomes were rated by mothers at 73 months (Study 1) and mothers, fathers, and teachers at 52 and 67 months (Study 2). In both studies, guilt moderated effects of effortful control: For highly guilt-prone children, variations in effortful control were unrelated to future disruptive outcomes, but for children who were less guilt prone, effortful control predicted such outcomes. Guilt may inhibit transgressions through an automatic response due to negative arousal triggered by memories of past wrongdoing, regardless of child capacity for deliberate inhibition. Effortful control that engages a deliberate restraint may offset risk for disruptive conduct conferred by low guilt. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Biodemographic trajectories of longevity

Old-age survival has increased substantially since 1950. Death rates decelerate with age for insects, worms, and yeast, as well as humans. This evidence of extended postreproductive survival is puzzling. Three biodemographic insights--concerning the correlation of death rates across age, individual differences in survival chances, and induced alterations in age patterns of fertility and mortality--offer clues and suggest research on the failure of complicated systems, on new demographic equations for evolutionary theory, and on fertility-longevity interactions. Nongenetic changes account for increases in human life-spans to date. Explication of these causes and the genetic license for extended survival, as well as discovery of genes and other survival attributes affecting longevity, will lead to even longer lives.     

稳定和改善焦炭质量的途径

从焦炭在高炉内的劣化原因着手,结合装炉煤灰分、粘结性、焦炭显微结构方面的影响因素,分析影响酒钢焦炭强度的因素,提出稳定和改善焦炭质量的途径.     

稳定配煤质量的途径

通过对来煤以及煤场现状的分析，指出济钢焦化厂在备煤工序上存在煤质难以判断、煤场容量小易导致混煤等问题，提出了利用煤岩分析仪判断来煤混煤情况和指导煤种堆放、建立煤场操作大票制度、利用20kg试验焦炉确定煤种结焦性等稳定配煤质量的措施．实施后，焦炭质量稳定，抗碎强度(M40)提高1．3％，耐磨强度(M10)改善0.47％，效果明显。     

Simultaneous multislice acquisition using rosette trajectories (SMART): a new imaging method for functional MRI

OBJECTIVES: Despite the recent introduction of new peroral drugs as well as neurosurgical methods for Parkinson's disease, treatment of late stage parkinsonian patients remains difficult and many patients become severely handicapped because of fluctuations in their motor status. Injections and infusions of apomorphine has been suggested as an alternative in the treatment of these patients, but the number of studies describing the effects of such a treatment over longer time periods is still limited. The objective was to investigate the therapeutic response and range of side effects during long term treatment with apomorphine in advanced Parkinson's disease. METHODS: Forty nine patients (30 men, 19 women; age range 42-80 years) with Parkinson's disease were treated for 3 to 66 months with intermittent subcutaneous injections or continuous infusions of apomorphine. RESULTS: Most of the patients experienced a long term symptomatic improvement. The time spent in "off" was significantly reduced from 50 to 29.5% with injections and from 50 to 25% with infusions of apomorphine. The quality of the remaining "off" periods was improved with infusion treatment, but was relatively unaffected by apomorphine injections. The overall frequency and intensity of dyskinesias did not change. The therapeutic effects of apomorphine were stable over time. The most common side effect was local inflammation at the subcutaneous infusion site, whereas the most severe were psychiatric side effects occurring in 44% of the infusion and 12% of the injection treated patients. CONCLUSION: Subcutaneous apomorphine is a highly effective treatment which can substantially improve the symptomatology in patients with advanced stage Parkinson's disease over a prolonged period of time.     

运用PLC实现硅整流自动控制

简要介绍了硅整流控制系统的组成、功能，实现控制功能的程序和人机界面的设计。     

运用PLC实现硅整流自动控制

简要介绍了硅整流控制系统的组成、功能,实现控制功能的程序和人机界面的设计。