Linearly many faults in Cayley graphs generated by transposition trees

We prove that when linearly many vertices are deleted in a Cayley graph generated by a transposition tree, the resulting graph has a large connected component containing almost all remaining vertices.     

人造参考星系统设计

简述了人造参考星系统，并用该系统作为大型望远镜主动光学和自适应光学的Ｓｈａｃｋ－Ｈａｒｔｍａｎ波面探测系统的光源。     

便携式多功能找星仪

找星仪是卫星地面站安装、调试、维修所必不可少的设备。旧的找星仪笨重、由于必须两人操作,很不方便。针对这些问题开发了便携式多功能找星仪。本文主要介绍了该设备的构成及其电路原理。     

控制连铸板坯星状裂纹的对策

回顾重钢七厂连铸板坯星状裂纹导致轧制钢板表面产生龟裂缺陷、以及对钢坯产生星裂的机理的认识过程,借助国外在这方面的研究成果进行对比分析,认为控制板坯星裂的最重要技术措施是采用"结晶器软冷却”工艺、以及控制钢的铁素体势和铜当量。     

Controlled radical polymerization of p-(iodomethyl)styrene—a route to branched and star-like structures

p-(Iodomethyl)styrene was polymerized under the action of a radical initiator (AIBN). The polymerization proceeds with degenerative chain transfer and leads to well defined branched polymers with functional primary and secondary iodomethyl groups as revealed by NMR studies. The obtained polymer can be further used as macroinitiator for radical polymerization of styrene. This polymerization proceeds in controlled way to polystyrene star polymers with reactive groups at the end of their arms. The characterization of branched and star structures was performed by NMR and GPC with absolute molar mass detection (MALLS).     

An Investigation of Information Systems Interoperability in UK Universities: Findings and Recommendations

This article reports on the key findings and implications of the Joint Information Systems Committee (JISC)-funded Online Catalogue and Repository Interoperability Study (OCRIS), a 3-month project which investigated the interoperability of Online Public Access Catalogues (OPACs) and Institutional Repositories (IRs) within UK universities. A series of detailed recommendations enumerate some of the ways in which they might begin to develop and support an interoperable systems landscape to the benefit of all key stakeholders.

The project combined quantitative and qualitative research methods including an online questionnaire distributed to staff within 85 universities, desk research, and two case studies conducted at the Universities of Cambridge and Glasgow.     

Disc cutters plane layout design of the full-face rock tunnel boring machine (TBM) based on different layout patterns

The quality of plane layout design of the disc cutters for the full-face rock tunnel boring machine (TBM) directly affects the balance of force distribution on the cutter head during the excavating. Various layout patterns have been adopted in practice during the layout design of the disc cutters. Considering the engineering technical requirements and the corresponding structure design requirements of the cutter head, this study formulates a nonlinear multi-objective mathematical model with multiple constraints for the disc cutters plane layout design, and analyses the characteristics of a multi-spiral layout pattern, a dynamic star layout pattern and a stochastic layout pattern. And then a genetic algorithm is employed to solve a disc cutters’ multi-spiral layout problem, and a cooperative co-evolutionary genetic algorithm (CCGA) is utilized to solve a disc cutters’ star or stochastic layout problems. The emphasis was put on the study of superiority of three different layout patterns. Finally, an instance of the disc cutters’ plane layout design was solved by the proposed methods using three different kinds of layout patterns. Experimental results showed the effectiveness of the method of combining the mathematical model with the algorithms, and the pros and cons of the three layout patterns.     

基于星体标定的光电跟踪系统测角精度评定

测角精度是光电跟踪系统中一项最重要的技术指标，通常是以校准塔和方位标为基准进行单项误差标定再综合，其过程繁锁、周期长。介绍一种基于星体标定的精度评价方法，建立了系统误差模型，分析了该方法的标定精度。以光电经纬仪为评价目标，研究了精度评定系统组成结构、试验条件、试验和数据处理方法。试验结果表明该方法具有标定过程简单、快速，标定精度高等优点，其标定误差小于3”。     

一种新的全天自主几何结构星图识别算法

提出了一种新的星图识别算法,该算法根据星敏感器的观测精度,在识别前去除星三角形的观测误差,对无误差的星三角形进行编码,构造特征量。导航三角形的识别只需基于单一特征量的匹配就可完成。多三角形的组合,有效地提高了正确识别率。仿真实验表明,该算法与传统的三角形算法相比,具有更好的实时性和鲁棒性。     

Modeling dynamic relationship types for subsets of entity type instances and across entity types

In a traditional ER model, once we specify a subclass or superclass relationship, any changes to that relationship are treated as schema evolution. Further, ER models are rigid in the sense that once a relationship type is specified across a set of entity types, an instance of relationship type occur when one instance of all participating entity types are specified. Therefore, it is difficult to introduce in a simplified manner all relationship types across subsets of given set of entity types. In this paper, we provide mechanisms to model in our extended ER model: (i) specification of dynamic relationship types across subsets of instances of entity types, (ii) a simplified specification of relationships across subsets of given set of entity types, and (iii) mapping our extended ER model to relational database schema. We also show through an e-contract example the utility of our extended ER model.