利用GPS布设水利隧洞工程控制网及精度分析

GPS定位技术以其高精度、全天候作业、操作简单、观测时间短等诸多优点而广泛应用于各种测量控制网的布设。文章从不同版本规范对GPS控制网有不同要求的角度探析GPS控制网的布设原则,并在实例工程中分析其精度。     

利用GPS布设水利隧洞工程控制网及精度分析

GPS定位技术以其高精度、全天候作业、操作简单、观测时间短等诸多优点而广泛应用于各种测量控制网的布设。文章从不同版本规范对GPS控制网有不同要求的角度探析GPS控制网的布设原则,并在实例工程中分析其精度。     

Propelling diverse leaders to the top: A developmental network approach

Scholars and practitioners are making a strong business case for greater representation of women and other underrepresented groups on senior management teams and boards. A model is developed that highlights how to create optimal developmental networks—groups of developers who help advance people's careers and personal growth—that can assist in propelling diverse leaders into the upper echelons of their organizations and board positions. Several literature streams are integrated in order to identify developmental networks that will help diverse leaders overcome barriers to breaking the glass ceiling in greater numbers. Numerous strategies intended to shape diverse leaders' network structure and content are discussed, as are contextual challenges that may inhibit optimal networks' development. Lastly, theoretical and practical implications for individuals and organizations are highlighted.     

The impact of implicit collective leadership theories on the emergence and effectiveness of leadership networks in teams

Leadership in today's high-performing teams is a relational process best understood from a multilevel emergent perspective. Implicit theories of leadership and followership play an important role in predicting leader emergence in more traditional hierarchical structures, but are inadequate for understanding and predicting leadership as networks in teams, as they do not consider the complex dynamics of leading and following activities inherent in such structures. To address this theoretical gap, we propose the concept of Implicit Leadership Network Theories (ILNTs) that integrates implicit leadership and followership theories with contemporary social network perspectives of leadership in teams to predict the shape and structure of leadership network emergence and subsequent team outcomes. More specifically, we propose that the combination of team member self-ILNTs (i.e., expectations regarding one's own role within a leadership network) and network-ILNTs (i.e., expectations regarding the prototypical team leadership structure) will shape the emergence and effectiveness of leadership in teams. We describe several prototypical team configurations of ILNTs and discuss implications for future research and human resource management.     

Multi-period location of flow intercepting portable facilities of an intelligent transportation system

Intelligent transportation systems are of great importance in urban traffic management. In this context variable message signs (VMS) play a major role in providing drivers with useful information during their trips.In this paper we consider the problem of finding the optimal location of a set of portable VMS on an urban network where flow patterns change during a time horizon.We propose two original solving approaches based on flow intercepting facility location ILP models.The paper presents an application of the proposed approaches to real-like test networks and discusses the results obtained providing some indications on their practical applications.     

Go ahead,leap: Triads and their practical and theoretical import: In response to “To leap or not to leap: Triads as arbitrary subsets of networks of connected dyads” by Anna Dubois

We agree with Dubois that, as supply chain management scholars, the object of our interest is, ultimately, supply networks. However, what is this supply network? Where does it end and where does it begin? It of course depends on research interest—one could study a dyad or a triad or a network of suppliers that exist upstream to an automaker or an industrial network that is stretched out so vast its outer edges overlap with other industries. Different units of analysis allow researchers to tackle different research questions.Then, why the focus on triads? A triad is the smallest network unit where we can observe how a link affects a link or a node affects a link either directly or indirectly connected—the quintessential network dynamics that a dyad by itself cannot capture. Therefore, there is nothing arbitrary about studying triads. If we say that we study networks, we have to begin by studying triads. In this rejoinder, we will present the practical and theoretical significance of triads. Also, we will make reference to supply networks as a “complex adaptive system” to frame triads in the larger supply network.     

Network flow-based strategies for identifying rail park-and-ride facility locations

Many cities are considering introducing or expanding rail service in an effort to diversify their modal splits. Park-and-rides are integral to this strategy because they represent private auto users’ access points to the system. Proper placement of such facilities is a strategic location decision, as it can conceivably decrease vehicular traffic on congested roadways while benefiting users. This paper models the decision to locate park-and-ride facilities in a network flow-based framework. From this perspective, optimal placement occurs at locations where vehicles will encounter facilities early during their journeys to a centralized area or major activity center. Locating park-and-rides in this fashion maximizes the chances of removing users from the network. These elements are demonstrated in three hypothetical placement scenarios that make use of synthetic network and traffic flow data. Results illustrate the functionality of our approach for identifying park-and-ride candidate locations. Lastly, implications of our work are discussed in light of broader planning concerns and practical demands on rail facility location.     

Leveraging the employee voice: a multi-level social learning perspective of ethical leadership

Extending social learning theory to a multi-level perspective, this study proposes a theoretical model that investigates both individual and team-level mechanisms that mediate the effect of ethical leadership on employee voice. Specifically, in terms of an individual-level social learning perspective, we suggest that an ethical leader acts as a prototype of a moral person (i.e. an ethical role model). From a team-level social learning perspective, we propose that, as a moral manager, team ethical leadership will foster an ethical climate within the team which will create a moral context that impacts employees’ behaviors. In both instances, employee voice behaviors will be enhanced through these mechanisms. Evidencing the importance of the interaction between leader behaviors and context for leader effectiveness, we also show that employees are more likely to regard their ethical leaders as ethical role models in a team that highly values ethical conduct (i.e. high in ethical climate). Results obtained from 47 managers and 211 subordinates in China support our theoretical model. The theoretical and practical implications of our findings are also discussed.     

创业团队成员信任对社会网络与企业创新能力关系的影响

本文通过对吉林省112家有效样本企业进行调查,将社会网络细分为内部社会网络和外部社会网络,在创业团队的定义下检验了社会网络与信任对新创企业创新能力的影响。研究结果表明,内外部社会网络都会对企业创新能力产生积极影响,而团队成员之间的信任则作为调节变量影响两者之间的关系。创业团队成员之间的信任越高,越有利于知识、信息的传播与交流,内部社会网络对企业创新能力的积极影响越大;但却易产生"非我发明症"现象,导致外部社会网络对企业创新能力的积极影响越小。     

物流基础设施网络节点的动态选址研究

物流基础设施网络节点的选址决策是一个长期决策,而随着时间的推移,需求和成本模式会随之变化,那么原来的选址决策就可能不是最优的,这时就需要确定一个随时间变化的选址方案,这个过程就是物流基础设施网络节点的动态选址.本文采用时间序列平滑预测法对需求进行预测,并据此用静态选址模型（重心法）得出结论,再运用动态规划技术,找出一个物流基础设施网络节点动态最优选址-再选址方案,使得计划期内的累积总利润现值最大化,并引入预测准确性因子来提高预测的准确性.     

Pre-averaging estimators of the ex-post covariance matrix in noisy diffusion models with non-synchronous data

We show how pre-averaging can be applied to the problem of measuring the ex-post covariance of financial asset returns under microstructure noise and non-synchronous trading. A pre-averaged realised covariance is proposed, and we present an asymptotic theory for this new estimator, which can be configured to possess an optimal convergence rate or to ensure positive semi-definite covariance matrix estimates. We also derive a noise-robust Hayashi–Yoshida estimator that can be implemented on the original data without prior alignment of prices. We uncover the finite sample properties of our estimators with simulations and illustrate their practical use on high-frequency equity data.     

The spatial effects of a tax on housing and land

This paper analytically investigates the spatial consequences of a tax on housing and land. In general, a property tax is not spatially neutral; instead it disproportionately affects certain parts of the city. The property tax can therefore create distributional inequities and can distort the pattern of residential and industrial location. We derive conditions on locational preferences and housing production that determine which parts of a city will be disproportionately affected by a property tax. Empirical estimates suggest that central locations will be disproportionately affected by property taxes.     

异因同果关联神经网络的研究

提出了一种异因同果关联神经网络模型,可以从不同角度分别建立不同的模型,并由其得到互不相同的模型预测值。异因同果关联神经网络模型将不同角度建立的模型有机结合起来,进而能够将多个神经网络模型进行综合考虑,得到一个综合的统一的模型预测结果。研究了新型模型的机理,结合实例进行仿真并与传统的神经网络模型的预测仿真结果比较,结果表明新型模型具有更高的预测精度。     

Discrete choice models and the housing price and travel to work elasticities of location demand

Multinomial logit and nested logit models of mode choice in travel to work and housing location choice are estimated from 1970 U.S. census data aggregated to small zones of the Chicago SMSA. The estimated models are then used to derive the “housing rent,” “travel time,” and “travel cost” elasticities of location demand. The effects of sampling variation, sample size, attribute inclusion, model specification, and estimation method on the estimated elasticities are evaluated and found to be important. The elasticities are also compared and found to agree with those obtained from other discrete choice models and, in the case of “housing rent,” with estimates obtained from models based on other theoretical structure.     

Convexity and duality properties of a quadratic intraregional location model

This paper has two main purposes. The first one is to analyse the convexity and duality properties of a quadratic intraregional location model that has been developed for long-term indicative planning in the Stockholm region. The second one is to review the results of Koopmans and Beckmann (1957) about the inadequacy of a linear price system in sustaining an optimal assignment of plants to locations when the costs of transporting intermediary commodities are taken into consideration. At the outset a model is formulated which is a transposition of a continuous Koopmans-Beckmann model into the urban scene. It is shown that this quadratic programming model is non-convex in all practical cases of interest, due to the simple fact that transportation costs increase with distance. A modification of the model is proposed in which the centralising transportation cost criterion is traded of against a decentralising so called congestion cost which penalizes over-exploitation of urban space. It is shown that the modified model tends to be convex. In the light of these results Kuhn- Tucker theory is used to derive a set of conditions that will ensure that the optimal solution is stable relative to all potential moves by individual decision-makers. This result forms the basis for the conclusion that the failure of the price system in the Koopmans-Beckmann model is rather due to properties of the quadratic criterion function than the integral restrictions on the variables.     

Orchestrating distributed data governance in open social innovation

Open Social Innovation (OSI) involves the collaboration of multiple stakeholders to generate ideas, and develop and scale solutions to make progress on societal challenges. In an OSI project, stakeholders share data and information, utilize it to better understand a problem, and combine data with digital technologies to create digitally-enabled solutions. Consequently, data governance is essential for orchestrating an OSI project to facilitate the coordination of innovation. Because OSI brings multiple stakeholders together, and each stakeholder participates voluntarily, data governance in OSI has a distributed nature. In this essay we put forward a framework consisting of three dimensions allowing an inquiry into the effectiveness of such distributed data governance: (1) openness (i.e., freely sharing data and information), (2) accountability (i.e., willingness to be held responsible and provide justifications for one's conduct) and (3) power (i.e., resourceful actors' ability to impact other stakeholder's actions). We apply this framework to reflect on the OSI project #WirVsVirus (“We versus virus” in English), to illustrate the challenges in organizing effective distributed data governance, and derive implications for research and practice.     

Evolutionary optimization of a technological knowledge network

Knowledge networks have two contradicting demands, increasing flow and decreasing cost. Maximizing the sum of these demands will result in an optimized network. On the basis of the evolutionary optimization algorithm, we suggest a quantitative way to produce an optimized technological knowledge network where optimality is defined as the maximization of overall benefit. Applied to Korea’s ICT network, such a network results in a total knowledge flow increase of up to 75% in absolute measures and 150% with due regard to cost. Our result supports the notion that self-organizing networks can be far from optimal, and thus active intervention by policymakers or managers is necessary to take full advantage of the potential benefits. Finally, with clear-cut suggestions about where to add new links and remove old ones according to potential benefits, this study sheds light on future policies with regard to evolutionary technology networks.     

Knowledge networks and universities: Locational and organisational aspects of knowledge transfer interactions

The aim of this paper is to explore the inter-organisational knowledge networks that universities in the UK engage in through their knowledge transfer activities. In particular, it analyses the extent to which organisational and locational factors are associated with the nature of these networks. Based on a UK-wide survey of universities, it is shown that the nature and formation of inter-organisational knowledge networks is related principally to the organisational characteristics of network actors, and secondarily to their spatial location. The characteristics of a network actor, in this case a university, are likely to influence the type, diversity and location of other actors with which it networks. Nevertheless, spatial location is an important secondary factor influencing network formation, especially the geographic reach of a university's network. It is further found that the value generated by universities from their knowledge networks is associated with the type of organisations within which they interact as well as their spatial location. It is concluded that such networks impact both regional innovation capability and regional competitiveness. The results have implications for policymakers, especially in terms of the spatial scale at which the demand and supply for university knowledge can be best mediated.     

Location Decisions of Competing Networks

Early entrants in markets with network effects usually occupy a “central location” and serve agents with “intermediate tastes,” whereas later entrants are niche players. Why would the first entrant choose to become a “general” network, given that later entrants will not have enough room for differentiation, resulting in a more intense competition for market share? In a Hotelling model with two rival networks, we show that for intermediate values of the network externality parameter the location equilibrium is indeed asymmetric: the first entrant locates at the center whereas the second entrant chooses an extreme (niche) location.     

How Do Social Networks Influence the Employment Prospects of People with Disabilities?

We explore the role of social networks used by people with disabilities for finding employment. In addition, we outline obstacles to network building for those with a disability. We contend that this group is often constrained and they underutilize their networks during job searches. Both factors are likely to result in negative employment outcomes and contribute to the employment gap between those with and without a disability. We outline how key network characteristics such as homophily, tie strength, and centrality influence job search outcomes for those with a disability differently than for those without a disability. Furthermore, we propose that although individuals with disabilities develop and rely upon networks that are comprised of close bonds with similar individuals that are either unemployed or underemployed in lower status positions, optimal networks for employment purposes should consist of diverse acquaintances that occupy central positions and higher status jobs within organizations. Finally, we outline propositions to guide future research on this neglected topic and also suggest practical implications.