基于统计可信度的压缩感知协作频谱检测算法

压缩感知为认知无线电的宽频谱感知提供了一种新的方法和思路。基于压缩感知的原理,提出了一种多认知用户协作场景下基于用户统计可信度的协作频谱检测算法。该算法使用正交匹配协作追踪算法获得认知区域内的频谱占用情况,根据不同认知用户频谱检测的历史准确度综合判定用户感知结果的统计可信度。仿真结果表明,该算法在不同用户数、不同采样值、不同信噪比变化范围下其检测性能均优于传统算术平均方法,有效改善了检测性能。     

基于多约束NSGA2算法的空管监视台站优化选址

为了实现空管监视台站的科学规划、合理布局,探讨了一种高效通用的优化选址算法。通过深入分析监视台站优化选址的问题,建立了多变量组合寻优的组网模型,提出了选址的简要约束条件和3个覆盖性能评估的目标函数,并在此基础上设计了空管监视台站优化选址的多约束NSGA2算法,该算法考虑了监视台站选址的各类影响因素加入多约束条件判定模块和种群修正模块。真实场景的仿真实例表明,优化输出的最优部署方案具有良好的覆盖性能,航路二重覆盖能达到98%以上,终端区域三重覆盖能达到95%以上。     

Socially responsible investing and stock performance: New empirical evidence for the US and European stock markets

This paper empirically examines the theoretically ambivalent relationship between socially responsible investing (SRI) and stock performance. It contributes to the existing literature by considering both the US and the entire European stock markets and by using consistent world-wide corporate sustainability performance data. Our portfolio analysis from 1998 to 2009 is based on the common four-factor model according to Carhart (1997), which comprises market return, size, value, and momentum factors. We show for the US and the European stock markets that SRI is associated with large-sized firms. The insignificant abnormal stock returns for SRI in both regions are the main result of our paper. Therefore, our study supports the view that SRI stocks are correctly priced by market participants, although we cannot rule out that a corresponding mispricing has existed before the beginning of our observation period in 1998.     

Perverse Audit Culture and Accountability of the Modern Public University

The audit culture which has developed in public universities has led to counter‐productive outcomes. Managerial oversight of academic work has reached a critical tipping point. Extensive auditing of research output by means of performance management assessment regimes motivated by a New Public Management mentality has damaged individual scholarship and threatened academic freedom. Such assessment regimes are perverse and conducive to the development of psychotic tendencies by universities. It is important to understand the effects of a perverse audit culture when re‐thinking and reforming approaches to university performance management. We suggest ways for public universities to acknowledge the need for accountability while remaining true to core academic purposes.     

The exit decision in the European venture capital market

This article analyses the exit decision in the European venture capital market, studying when to exit and how it interacts with the exit form. Using a competing risks model we study the impact on the exit decision of the characteristics of venture capital investors, of their investments and of contracting variables. Our results reveals that the hazard functions are non-monotonic for all exit forms and suggest that, in Europe, Initial Public Offering candidates take longer to be selected than trade sales. Moreover our results show that, in Europe, venture capitalists associated with financial institutions have quicker exits (stronger for trade sales), and highlight the importance of contracting variables on the exit decision. An unexpected result is that the presence on the board of directors leads to longer investment durations.     

Linear predictability vs. bull and bear market models in strategic asset allocation decisions: evidence from UK data

Most papers in the portfolio choice literature have examined linear predictability frameworks based on the idea that simple but flexible Vector Autoregressive (VAR) models can be expanded to produce portfolio allocations that hedge against the bull and bear dynamics typical of financial markets through careful selection of predictor variables that capture business cycles and market sentiment. Yet, a distinct literature exists that shows that non-linear econometric frameworks, such as Markov switching, are also natural tools to compute optimal portfolios arising from the existence of good and bad market states. This paper examines whether and how simple VARs can produce portfolio rules similar to those obtained under a simple Markov switching, by studying the effects of expanding both the order of the VAR and the number/selection of predictor variables included. In a typical stock-bond strategic asset allocation problem for UK data, we compute the out-of-sample certainty equivalent returns for a wide range of VARs and compare these measures of performance with those of non-linear models. We conclude that most VARs cannot produce portfolio rules, hedging demands or (net of transaction costs) out-of-sample performances that approximate those obtained from simple non-linear frameworks.     

Loosely Coupled Results Control in Dutch Municipalities

This paper analyses the implementation of the ‘dual system’ in Dutch municipalities which was part of a package of New Public Management‐reforms. This system was stimulated by Dutch central government and called for more accountability for performance of municipal managers and the board of mayor and aldermen, as well as for the use of more output and outcome information. Interviews of participants on four different hierarchical levels in 12 municipalities show that the practices of output management at different hierarchical levels are only loosely coupled to each other (‘vertical loose coupling’). We also found some degree of ‘horizontal loose coupling’ at each hierarchical level between result orientation, the development of output indicators and the use of output information for performance evaluation. The paper analyses the reasons why municipalities encounter difficulties in designing a comprehensive and coherent performance management system.     

创客资本对创新绩效的影响机制研究

伴随着时代的发展,创客将成为未来社会创新的主体,而创客资本则是创客实现创新绩效的最根本的驱动力。研究基于社会认知理论探究了创客资本对创新绩效的影响机制,通过实证研究检验了创客资本对创新绩效的直接效应、创新效能感的中介作用,以及知识分享的调节作用,系统的阐述了创客资本对创新绩效的影响机制和路径,这将有助于我国人才驱动创新、创新驱动发展战略的推进和实施。     

Leveraging green HRM for firm performance: The joint effects of CEO environmental belief and external pollution severity and the mediating role of employee environmental commitment

The topic of green human resource management (HRM) has drawn increasing attention of HRM scholars in the past decade. Recent research has called for more studies to identify the antecedents of green HRM used in organizations and explore the mediating mechanisms through which green HRM is related to performance outcomes. This study represents an effort to address these research needs by examining the joint effects of chief executive officer (CEO) environmental belief and external pollution severity on the use of green HRM and testing the mediating role of employee environmental commitment in the relationship between green HRM and firm performance. Drawing upon data collected from multiple sources (i.e., survey data from chief executive officer (CEOs), chief financial officers (CFOs), HR managers and employees, and archival data from government statistics), we found that CEO's environmental belief is significantly related to the use of green HRM, especially for companies operating in locations with severer pollution. Green HRM in turn has a positive relationship with the firm's environmental and financial performances via employee commitment to the environment. The findings highlight the often-overlooked role of in the strategic HRM literature pertinent to environmental management and clarify the antecedents and influential mechanisms of green HRM at the firm level of analysis. We also discuss theoretical and practical implications in this study.     

不同地板结构对建筑物节能防水性能提升研究

以具体工程的地板结构为案例,对比架空地板、普通实木地板以及普通钢筋混凝土地板在施工过程中产生的环境效益,系统研究建筑物的节能防水性、尺寸匹配,进而评价不同地板结构对建筑物的节能防水性能的影响。结果表明: 普通实木地板以及普通钢筋混凝土地板夏季易吸湿膨胀,冬季易干缩,节能防水性能较差;架空地板节能防水性、尺寸匹配等性能均优于普通实木地板以及普通钢筋混凝土地板,具有施工方便、耐久性好、易维修等特点,具有广阔的应用前景。