A powerful graphical pulse sequence programming tool for magnetic resonance imaging

A powerful graphical pulse sequence programming tool has been designed for creating magnetic resonance imaging (MRI) applications. It allows rapid development of pulse sequences in graphical mode (allowing for the visualization of sequences), and consists of three modules which include a graphical sequence editor, a parameter management module and a sequence compiler. Its key features are ease to use, flexibility and hardware independence. When graphic elements are combined with a certain text expressions, the graphical pulse sequence programming is as flexible as text-based programming tool. In addition, a hardware-independent design is implemented by using the strategy of two step compilations. To demonstrate the flexibility and the capability of this graphical sequence programming tool, a multi-slice fast spin echo experiment is performed on our home-made 0.3 T permanent magnet MRI system     

Exploring regression structure with graphics

Summary We investigate the extent to which it may be possible to carry out a regression analysis using graphics alone, an idea that we refer to asgraphical regression. The limitations of this idea are explored. It is shown that graphical regression is theoretically possible with essentially no constraints on the conditional distribution of the response given the predictors, but with some conditions on marginal distribution of the predictors. Dimension reduction subspaces and added variable plots play a central role in the development. The possibility of useful methodology is explored through two examples. Read before the Spanish Statistical Society at a meeting organized by the Carlos III University of Madrid on Wednesday, April 21, 1993     

罗特曼透镜独立设计参数探讨

介绍了罗特曼透镜的理论设计公式,探讨了独立设计参数的选取范围及各独立设计参数的变化对透镜性能的影响。实际制作的宽频带罗特曼透镜实测结果印证了独立设计参数选取范围的合理性。     

管网独立后我国储气库公司的经营策略探讨

随着我国油气管理体制改革的不断推进，原来捆绑经营的地下储气库（以下简称储气库）将与管道逐步实现业务分离、财务独立乃至产权独立，如何做好储气服务的经营，便成为储气库运营企业亟待思考并解决的问题。为此，以美国储气库运营企业为例，系统分析了其在天然气市场化改革前后管理体制、服务类型和经营策略的变化，进而结合我国储气库业务经营中的关键因素和现存问题，对我国储气库企业的经营提出了建议。结论认为：①美国天然气市场化改革之后，传统的储气服务商通过设立子公司的形式实现了管输与储气的财务分离和经营统一，新建储气库通过开放季的形式进行预售从而锁定客户，将注采能力作为经营重点加强管理，向老客户提供优先续约权从而兼顾公平与效益；②我国的储气库经营还面临着现行储转费测算方法难以反映储气库实际运行成本、对注采能力重要性的认识有待加强等储多问题；③我国储气库经营企业应建立新的储气服务费定价机制，加强对注采能力的管理和经营，将城市燃气企业作为重点用户加强管理并与之深入合作，在合同设计中对气质、注采能力分配等关键参数进行明确规定，进一步细化服务细则。     

基于保护独立和信息共享的变电站通信结构

该文从继电保护设备的独立性和网络信息共享两方面出发,分析了变电站通信的整体结构和原则。在合并单元和智能终端集成的基础上,提出将继电保护及相关设备的通信接口分为站域信息接口、保护功能接口和过程信息接口,阐述了三种接口的具体功能,进一步采用了信息映射技术和过程信息服务器技术来实现设备间的信息交互;给出了典型的220kV和110kV间隔的通信结构示意图,并阐述了实现过程。最后对该通信结构在工程应用中的技术难点进行了分析。文中提出的通信结构,简化了现有的点对点通信系统,实现了保护设备物理连接和保护功能的完全独立性,同时兼顾了保护功能信息的共享和监视。     

《啊,拓荒者!》所蕴含的女性主义追求目标

20世纪美国最杰出的女性小说家薇拉.凯瑟创作的《啊,拓荒者!》塑造出两位截然不同的女性形象——独立女性的代表亚历山德拉·柏格森以及传统女性的典型麦丽·托维斯基。从女性主义视觉,通过解析两位女主人公不同的生活轨迹,探究女性主义者的追求目标。     

基于独立稀疏SAE的多风电场超短期功率预测

为应对多风电场超短期预测模型中输入和输出变量众多、变量间的时空关系复杂等问题,提出一种基于独立稀疏堆叠自编码器的多风电场超短期功率预测方法.该方法基于降维编码、特征预测和重构解码相结合的预测框架,首先设计了一种独立稀疏双层堆叠自编码器提取多维风电功率的空间独立特征,并将其作为预测对象分别预测,最后将特征预测的结果重构解...     

Using retrospective sampling to estimate models of relationship status in large longitudinal social networks

Estimation of longitudinal models of relationship status between all pairs of individuals (dyads) in social networks is challenging due to the complex inter-dependencies among observations and lengthy computation times. To reduce the computational burden of model estimation, a method is developed that subsamples the “always-null” dyads in which no relationships develop throughout the period of observation. The informative sampling process is accounted for by weighting the likelihood contributions of the observations by the inverses of the sampling probabilities. This weighted-likelihood estimation method is implemented using Bayesian computation and evaluated in terms of its bias, efficiency, and speed of computation under various settings. Comparisons are also made to a full information likelihood-based procedure that is only feasible to compute when limited follow-up observations are available. Calculations are performed on two real social networks of very different sizes. The easily computed weighted-likelihood procedure closely approximates the corresponding estimates for the full network, even when using low sub-sampling fractions. The fast computation times make the weighted-likelihood approach practical and able to be applied to networks of any size.     

基于社会团体能力和独立性视角团体标准质量提升研究

新《标准化法》赋予了团体标准相应的法律地位,开展团体标准化工作成为社会团体彰显其社会服务价值的一种有效方式。社会团体的能力和独立性建设对其开展团体标准化工作的效果有重要影响,本文分析了社会团体要做好团体标准化工作,提高团体标准质量应从基础保障能力、标准化管理能力、社会协调能力和独立性方面加强社会团体建设,并提出了相关建议。