“信号与系统”课程教学方法初探

针对"信号与系统"课程理论性强、数学公式多,学生理解和掌握困难以及实验条件有限等现状,提出了运用主线教学法、比较法等多种教学方法,将MATLAB仿真软件引入课程教学的各个环节,加强习题课教学等措施以期达到提高教学效果的目的。最后通过一个实例说明了该教学方法的具体运用。     

Flow Signals: Evidence from Patent and Alliance Portfolios in the US Biopharmaceutical Industry

Integrating signalling theory and the portfolio diversity literature, we theorize that diversity in a firm's patent and alliance portfolios sends contrasting flow signals impacting its market value in a nuanced way. Diversity in an alliance portfolio mediates the patent portfolio diversity – market value relationship by suppressing the negative effect of patent portfolio diversity creating an overall positive effect. We test our mediation model on a longitudinal set of 225 US biopharmaceutical firms that were awarded 17,078 patents and participated in 37,744 alliances between 1990 and 2006. Our theory and findings contribute three novel insights. First, we demonstrate the value of a temporal lens in explaining why diversity in a firm's patent and alliance portfolios send flow signals that establish expectations among market observers and have performance implications. Second, establishing that patent and alliance portfolio diversity are temporally sequenced provides compelling evidence for the value of studying multiple types of portfolios, their temporal relationships and effects on firm outcomes. Third, since diversity in a firm's portfolios can send contrasting flow signals conditioned on the cognitive demands and proximity involved in interpreting the signals, firms that do not maintain a ‘signalling fit’ with market observers increase the probability of unintentional negative signalling effects.     

The implications,challenges and benefits of a complexity-orientated Futures Studies

Complexity science is increasingly cited as an essential component of a Futures Studies (FS) capable of assisting with the wide-ranging and complex societal problems of the 21st century. Yet, the exact implications of complexity science for FS remain somewhat opaque. This paper explicitly sets out the challenges for FS that arise from six complexity science concepts: (1) irreversibility of time (2) path dependence 3) sensitivity to initial conditions (4) emergence and systemness (5) attractor states (6) complex causation. The discussion highlights the implications of these challenges for FS tools such as horizon scanning and weak signals, and sets out the benefits of overcoming the challenges to create an explicitly complexity-orientated FS. The discussion concludes with a set of questions summarising the challenge for FS from complexity science with the aim of stimulating a discussion as to how they can be met. The concluding remarks make some initial suggestions in this regard.     

Small seeds for grand challenges—Exploring disregarded seeds of change in a foresight process for RTI policy

The recent turn in research, technology and innovation (RTI) policy towards challenge-led strategies is posing new demands to Foresight methodology. RTI Foresight practitioners need to complement their well developed set of technology oriented methods with equally sophisticated approaches tackling societal aspects of innovation. In this paper we aim to make a contribution to this requirement. Building on user innovation theory we argue that demand oriented RTI Foresight needs to systematically integrate voices and hypotheses from the fringes of the innovation system. In order to develop a sound approach for this we set out from well established Foresight theory on “weak signals” and “cognitive biases”. Adopting a constructivist stance towards such signals leads us to the need to set up a socially robust, diverse discourse on “seeds of change hypotheses”. We then outline a practical implementation of such a discourse in the context of the recent Foresight process of the Federal Ministry of Education and Research (BMBF) in Germany. We describe and discuss the experience of this Foresight process and suggest avenues for further development of the approach.     

Context dependent beliefs

This paper examines a model where the set of available outcomes from which a decision maker must choose alters his perception of uncertainty. Specifically, this paper proposes a set of axioms such that each menu induces a subjective belief over an objective state space. The decision maker’s preferences are dependent on the realization of the state. The resulting representation is analogous to state-dependent expected utility within each menu; the beliefs are menu dependent and the utility index is not. Under the interpretation that a menu acts as an informative signal regarding the true state, the paper examines the behavioral restrictions that coincide with different signal structures: elemental (where each element of a menu is a conditionally independent signal) and partitional (where the induced beliefs form a partition of the state space).     

基于宏程序的椭圆轮廓的数控车加工

宏程序在数控编程中有着广泛的应用。文章结合两种椭圆曲线宏程序编程实例,介绍了宏程序在非圆曲线中的编制方法和技巧,分析表明:宏程序数控编程具有编程快捷和程序短小精悍的显著特点,尤其适用于一些含非圆曲线零件的数控编程加工。     

基于最大似然估计的分集信号中频合成方法

为了降低分集信号合成时输入信号的信噪比要求,提出了一种分集信号的中频合成方法 。该方法利用最大似然估计和迭代算法,通过计算输出合成信号和输入分集信号的相关值获 得合成权值,在中频实现信号合成。仿真和实验结果表明,该方法放宽了输入信号信噪比要 高于解调捕获门限这一要求,能自动实现最大合成增益。     

舰载通信信号侦察接收系统

在分析沿海地区复杂电磁环境构成因素的基础上,阐述了舰载通信信号侦察接收系 统的技术体制、侦收方法及特点,探讨了舰载通信信号侦察接收系统为适应复杂电磁环境的 解决措施,并在实际工程应用中证明改进措施能够很好地解决舰载通信信号侦察接收机的实 际使用问题,保证其具有大侦收带宽、高灵敏度、大动态范围、强抗干扰能力。     

Polite feedback signals in same-gender conversation-An investigation into the theory of politeness impact on the male speakers and female speakers use feedback signals in the same-gender conversation

交流是每天日常生活中分享知识和经验所必不可少的一部分。对话作为交流手段的一种主要形式,是一种即时即地发生的社会活动。反馈语是交互子系统中的(即对话过程中的)一种特定用语,主要表现为使用特定或固定的语言学词汇来引出上下文或是帮助理解或是暗示说话人态度等等。男性和女性参与者在会话过程中使用不同的策略或是选择合适的反馈语表达他们的意见,想法,目的,态度等等进而展现他们的礼貌。     

The value contribution of strategic foresight: Insights from an empirical study of large European companies

This paper focuses on exploring the potential and empirically observable value creation of strategic foresight activities in firms. We first review the literature on strategic foresight, innovation management and strategic management in order to identify the potential value contributions. We use survey data from 77 large multinational firms to assess how much value is generated from formalized strategic foresight practices in these firms. We show that it is possible to capture value through (1) an enhanced capacity to perceive change, (2) an enhanced capacity to interpret and respond to change, (3) influencing other actors, (4) and through an enhanced capacity for organizational learning.