A pure proactive scheduling algorithm for multiple earth observation satellites under uncertainties of clouds

Most earth observation satellites (EOSs) are equipped with optical sensors, which cannot see through clouds. Hence, observations are significantly affected and blocked by clouds. In this work, with the inspiration of the notion of a forbidden sequence, we propose a novel assignment formulation for EOS scheduling. Considering the uncertainties of clouds, we formulate the cloud coverage for observations as stochastic events, and extend the assignment formulation to a chance constraint programming (CCP) model. To solve the problem, we suggest a sample approximation (SA) method, which transforms the CCP model into an integer linear programming (ILP) model. Subsequently, a branch and cut (B&C) algorithm based on lazy constraint generation is developed to solve the ILP model. Finally, we conduct a lot of simulation experiments to verify the effectiveness and efficiency of our proposed formulation and algorithm.     

工程建筑物变形观测若干问题的探析

随着人们生活水平的提高，人们对当代建筑的要求也越来越高。工程建筑的稳定性、可靠性不仅关系到建筑行业的发展，更关系到广大人民群众的利益。本文就工程建筑变形观测若干问题进行了相关的分析。     

Classification of brain hemodynamic signals arising from visual action observation tasks for brain–computer interfaces: A functional near-infrared spectroscopy study

A brain–computer interface (BCI) is a way of translating an individuals’ thoughts to control a computer or an external mechanical device. Studying brain activities in a reproducible manner, this study explores the possibility of using real-time functional-near infrared spectroscopy (fNIRS) to detect brain hemodynamic features for BCI commands. Sixteen channel brain activities associated with two distinct mental tasks were measured from seven healthy subjects. The tasks represented neural activities arising from a visual observation of a motor action related to hand movements of the subjects. Sensitive signatures of task relevant neural activities were further extracted from hemodynamic signals in the prefrontal cortex of the brain, and subsequently were translated into pre-determined computer commands using a set of algorithms. The decoded commands allowed volunteer subjects to control an external device in real-time through their mental intentions. The obtained results demonstrate the potential of the current study as an alternative fNIRS-BCI paradigm.     

Influence of the SiC matrix introduction time on the microstructure and mechanical properties of Cf/Hf0.5Zr0.5C-SiC ultra-high temperature composites

C_f/Hf_0.5Zr_0.5C-SiC composites were prepared by introducing Hf_0.5Zr_0.5C matrix (11 cycles) and SiC matrix (9 cycles) into the carbon cloth preform through precursor impregnation and pyrolysis (PIP) process. The influence of the introduction time of SiC matrix on the microstructure and mechanical properties of C_f/Hf_0.5Zr_0.5C-SiC composites was studied, and the results show that with the increase of the PIP cycles of the SiC matrix introduced before Hf_0.5Zr_0.5C matrix, the composite open porosity decreased, and the flexural strength and modulus presented an obvious upward trend. CS45 sample, which has 4 cycles of PIP SiC introduced in advance, has the highest flexural strength, flexural modulus and interfacial shear strength of 402.73 ± 35.73 MPa, 56.92 ± 3.97 GPa and 100.88 ± 7.79 MPa, respectively. Hf_0.5Zr_0.5C matrix has a loose and porous structure, so when more SiC matrix was introduced in advance, its covering effect on the surface of fibers led to less intra-bundle pores and thusly denser composite structure, and due to the compactness of SiC matrix, better overall bonding of fiber, interface and matrix was achieved, as well as better load transfer effect, which led to obvious interfacial debonding and cracking based on the in-situ SEM observation during flexural tests. While in the sample without pre-introduced SiC, the cracking occurred mainly between the interface and porous matrix and the overall performance of the material was poor.     

谈建筑物沉降观测的方法和注意事项

阐述了沉降监测在点位布设、施工方法、数据整理过程中用到的典型方法,并对后期数据沉降量的计算所用时点差法和分析数据用的回归模型做了简单的阐述,以期指导实践。     

海洋观测预报及防灾减灾标准体系研究

海洋观测预报及防灾减灾标准体系研究是该领域标准化工作的基础,本文阐述了海洋观测预报及防灾减灾标准体系研究的意义及内容,并从标准体系结构和明细表两方面进行了详细讨论。     

基于天地基测控的空间目标联合定轨研究

天基空间目标监视系统是获取空间目标态势信息的重要手段和未来发展方向,然而仅仅利用星间测量信息进行空间目标轨道确定会产生亏秩现象.在对自主定轨亏秩问题的本质进行探讨的基础上,提出了基于天地基测控信息进行空间目标和监视平台的联合定轨策略,可以较好地解决轨道确定中亏秩问题.本文设计了由四颗高轨监视平台和两个地面测控站构成的天...     

近地边界层台风观测及湍流特征参数分析

通过近海岸测风塔获取了台风达维(0518)、珍珠(0601)、派比安(0606)登陆过程中10m高度三维脉动风速数据,对近地10m高度平均风特性和湍流特性进行了分析和研究。基于台风观测结果,分析了不同来流方向和地貌状况下,风剖面指数值、摩擦速度、湍流度和阵风因子等湍流参数及其相关性。分析结果表明: 摩擦速度与平均风速呈正相关,摩擦速度随平均风速增大而增大;风剖面指数值随平均风速增大而减小;各方向湍流度随平均风速增大而减小;阵风因子与湍流度呈线性关系。通过拟合实测湍流参数相关性,提出了10m标准高度台风湍流度、阵风因子的计算式,可为台风多发区域低矮房屋的抗风设计提供参考.     

低碳钢在高温共焦激光扫描显微镜下马氏体相变的原位观察研究

利用高温共焦激光扫描显微镜,对低碳钢进行了马氏体相变的原位动态观察。结果表明,实验用低碳钢在连续冷却过程中形成板条马氏体,Ms点约为373 ℃,Mf点约为300 ℃。板条马氏体主要在退火孪晶处以及奥氏体晶界及其角隅处形核,或者在先形成的板条处形核,再以60°或120°角向奥氏体晶内生长。板条束的形成也有两种类型,一类以先形成的板条为基准逐步形成彼此平行的板条束,另一类则由先形成的板条触发60°或120°方向的板条。最终构成正三角形、平行四边形等几何形状。     

Husbands' and wives' alcohol use disorders and marital interactions as longitudinal predictors of marital adjustment.

In this longitudinal study, the relationships among wives' and husbands' lifetime alcoholism status, marital behaviors, and marital adjustment were tested. Participants were 105 couples from the Michigan Longitudinal Study (MLS), an ongoing multimethod investigation of substance use in a community-based sample of alcoholics, nonalcoholics, and their families. At baseline (T1), husbands and wives completed a series of diagnostic measures, and lifetime diagnosis of alcohol use disorder (AUD, as defined in the Diagnostic and Statistical Manual of Mental Disorders, 4th ed.), was assessed. Couples completed a problem-solving marital interaction task 3 years later at T2, which was coded for the ratio of positive to negative behaviors. Couples also completed a measure of marital adjustment at T4 (9 years after T1 and 6 years after T2). Results showed that husbands' lifetime AUD predicted lower levels of their wife's positive marital behaviors 3 years later but was not related to their own or their wife's marital adjustment 9 years from baseline. By contrast, wives' lifetime AUD had direct negative associations with their own and their husband's marital satisfaction 9 years later, and wives' marital behaviors during the problem-solving task predicted their own and their husband's marital satisfaction 6 years later. Findings indicate that marital adjustment in alcoholic couples may be driven more by the wives' than the husbands' AUD and marital behavior. Implications for intervention with alcoholic couples were discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)