CertainC*-algebras with real rank zero and their corona and multiplier algebras: II

We first determine the homotopy classes of nontrivial projections in a purely infinite simpleC*-algebraA, in the associated multiplier algebraM(A) and the corona algebraM A/A in terms ofK _*(A). Then we describe the generalized Fredholm indices as the group of homotopy classes of non-trivial projections ofA; consequently, we determine theK _*-groups of all hereditaryC*-subalgebras of certain corona algebras. Secondly, we consider a group structure of *-isomorphism classes of hereditaryC*-subalgebras of purely infinite simpleC*-algebras. In addition, we prove that ifA is aC*-algebra of real rank zero, then each unitary ofA, in caseA it unital, each unitary ofM(A) and ofM(A)/A, in caseA is nonunital but -unital, can be factored into a product of a unitary homotopic to the identity and a unitary matrix whose entries are all partial isometries (with respect to a decomposition of the identity).Partially supported by a grant from the National Science Foundation.     

矩阵特征值的几个不等式

研究矩阵特征值的上、下界以及特征值的实部、虚部的不等式 ,给出了特征值一些新的上界和下界     

一个不定方程以及它的实数解

研究了一类不定方程 ,并获得了它的所有实数解     

管理人因素对风险项目期权估值的影响

本基于对风险项目及其“孪生证券”风险和收益特性的分析，认为真正的“孪生证券”实际中很难存在，进而提出利用“近似孪生证券”与无风险证券构造资产组合来复制实物期权收益特征，利用无风险套利分析确定项目实物期权价值的方法。但考虑到管理人因素造成的实物期权内部风险特征的不可复制性，本进一步提出利用“确定性等值”将内部风险价值V1具体化，从而实现对“近似孪生证券”方法进行修正。     

技术创新与增长期权定价

本采用了净现值(NPV)和实物期权定价方法对一个实际的MMDS的发射放大器项目进行了定价，并对两种方法定价的结果进行了分析和对比。由于实物期权方法定价的结果包含项目中的增长期权和放弃期权的价值，因而实物期权方法定价的结果比NPV方法定价的结果更合理和更高。     

On perturbations of matrix pencils with real spectra, a revisit

This paper continues earlier studies by Bhatia and Li on eigenvalue perturbation theory for diagonalizable matrix pencils having real spectra. A unifying framework for creating crucial perturbation equations is developed. With the help of a recent result on generalized commutators involving unitary matrices, new and much sharper bounds are obtained.

     

Reliability of commercial triple junction concentrator solar cells under real climatic conditions and its influence on electricity cost

This paper proposes a methodology for assessing the concentrator solar cell reliability in a real application for a given location provided the results from accelerated life tests. We have applied this methodology for the evaluation of warranty times of commercial triple junction solar cells operating inside real concentrator modules in Golden (Colorado, USA), Madrid (Spain) and Tucson (Arizona, USA) for the period 2012–2015. Warranty times in Golden and Madrid, namely, 68 and 31 years, respectively, for the analysed period, indicate the robustness of commercial triple junction solar cells. Nevertheless, the warranty time of 15 years for Tucson suggests the need of improvement in the heat extraction of the solar cell within the concentrator module. Therefore, the influence of the location on the reliability of concentrator solar cells is huge, and it has no sense to supply general reliability values for a given concentrator product. The influence of these warranty times for the three locations on the levelised cost of electricity has been analysed. Cost of €c10–12/kWh can be achieved nowadays, while after 1 GW_p cumulative installed power, a dramatic reduction to levels of €c2–3/kWh is achievable. Copyright © 2017 John Wiley & Sons, Ltd.     

国外激光切割实时监测技术的最新进展

近年来,国外对激光切割实时监测技术进行了大量的研究,多数采用在切割前沿的正上方采集其近红外辐射信号的监测方法.详细介绍了几种较为典型的实时监测方法及其研究成果,并按工业化应用的要求分析了各自的利弊.     

第十讲数字信号处理与数字信号处理器(DSP)

文章简要介绍了“数字信号处理”与“数字信号处理器（DSP）”的发展历史．在数字信号处理的应用中，实时实现是非常重要的，而DSP在实时处理中，扮演了一个重要的角色．文章中还介绍了DSP在实际应用中的一些关键技术，例如DSP的种类和选型，DSP的开发工具，实时软件的开发过程等．最后，还介绍了一些DSP的应用实例，如语音编码器，视频电话和视频会议系统，用于雷达和声纳的DSP并行处理系统     

Improving Memory Efficiency of Dynamic Memory Allocators for Real‐Time Embedded Systems

Dynamic memory allocators for real‐time embedded systems need to fulfill three fundamental requirements: bounded worst‐case execution time, fast average execution time, and minimal fragmentation. Since embedded systems generally run continuously during their whole lifetime, fragmentation is one of the most important factors in designing the memory allocator. This paper focuses on minimizing fragmentation while other requirements are still satisfied. To minimize fragmentation, a part of a memory region is segregated by the proposed budgeting method that exploits the memory profile of the given application. The budgeting method can be applied for any existing memory allocators. Experimental results show that the memory efficiency of allocators can be improved by up to 18.85% by using the budgeting method. Its worst‐case execution time is analyzed to be bounded.