An approach to technical risk assessment

This paper describes a framework for assessment of the risk that a proposed machine or system, such as an aircraft or computer, will not operate to its required performance specifications when it is developed. The method is based upon decomposition of the system under assessment into a hierarchy of functionally or structurally defined assessment areas. Within each area, technical risks, and methods of assessing these risks, are identified. The framework provides a systematic structure for selecting assessment methods and integrating results of the use of selected methods into a coherent overall assessment of the system.     

德国建造规划的技术框架

本文基于建造规划的课题研究,以建造规划中的重要符号——建造窗口为核心,系统总结了建造规划的技术框架,并进而详细剖析了其主要技术特点。     

冷弯薄壁型钢构件的直接强度设计法

受压或受弯的冷弯薄壁卷边槽钢有板件局部屈曲，截面畸变屈曲和整体弯曲屈曲或弯扭屈曲三种模式。本文着重介绍板件的相关屈曲和计算截面畸变屈曲应力的方法并阐述了三种屈曲模式之间的相关关系。指出用传统的有效截面设计法计算受压和受弯冷弯薄壁卷边槽钢承载力的弊端，较详细地说明了用构件全截面计算的直接强度设计法。     

LINGUISTIC FUZZY SYSTEMS AND THEIR APPLICATIONS IN ECONOMETRICS

This paper gives a brief summary of the linguistic fuzzy systems iheory and describes its possible application in econometric modelling. The essential feature of the used approach is a transformation of if-then rale bases into approximative deterministic behavior functions of considered economic systems.     

Iterative Fourier transform algorithm: comparison of various approaches

In this paper, a convergence of various approaches within the iterative Fourier transform algorithm (IFTA) is analysed for the case of phase-only diffractive optical elements with quantized phase levels (either binary or multilevel structures). Firstly, the general scheme of the IFTA iterative approach with partial quantization is briefly presented and discussed. Then, the special assortment of the general IFTA scheme is given with respect to quantization constraint strategies. Based on such a special classification, the three practically interesting approaches are chosen, further analysed and compared with each other. The performance of these algorithms is compared in detail in terms of the development of the signal-to-noise ratio characteristic with respect to the number of iterations, for various input diffusive-type objects chosen. Also, the performance of the complex spectra developments is documented for typical computer reconstruction results. The advantages and drawbacks of all approaches are discussed, and a brief guide on the choice of a particular approach for typical design tasks is given. Finally, two ways of amplitude elimination within the design procedure are considered, namely direct elimination and partial elimination of the amplitude of the complex hologram function.     

九顶山铜钼矿井下通风系统阻力测定结果分析与对策措施

以九顶山铜钼矿为例,系统介绍矿井通风阻力的测定方法、测点布置及测定路线选择,依据测定结果对矿井通风系统进行合理性分析,并提出降低矿井通风阻力的对策措施。为降低通风电耗、减少通风费用、减少风压损失和保证矿井安全生产提供科学的理论依据。     

Stimulated emission via quantum interference: Scattering of one-photon packets on an atom in a ground state

Abstract

Usually it is assumed that the stimulated emission appears as a consequence of the Bose—Einstein statistics of photons and that to observe this effect at least two excitations have to be initially present in the atom—field system. That is, both the atom and the electromagnetic field have to be excited. In this paper we show that stimulated emission can appear exclusively as a consequence of quantum interference in a system with just a single excitation. Specifically, we consider a single two-level atom which is initially in its lower energy state and it interacts with a single-photon multi-mode wave packet. We show that for a proper choice of the photon-wave packet the atom can exhibit stimulated emission.     

Selection of strategies in judgment-based effort estimation

We currently know little about the factors that motivate the selection and change of strategy in judgment-based effort estimation. A better understanding of these issues may lead to more accurate judgment-based effort estimates and motivates the four experiments reported in this paper. The experiments’ two main results are the identification of the importance of “estimation surprises” (large estimation errors) to motivate estimation strategy change and the large individual variation in the initial choice of estimation strategy. The individual variation seems not only to be a result of differences in previous experiences, but also a result of differences in the mental “accessibility” of the strategies. We found, for example, that the use of a type of strategy was increased when we instructed a developer to use the same type of strategy on unrelated tasks immediately before.