网络、资源与竞争优势:一个企业社会学视角下的观点

资源一直是企业获取竞争优势的主要战略因素。本文以“传统资源”为研究起点，刻画了企业行为的社会嵌入性特征，并通过引入“网络资源”这一概念揭示出一个更加全面、以企业网络及其关系资本为背景的资源分析框架，完善地拓展了传统的资源基础论观点。     

基于冠层光谱和BP神经网络的水稻叶片氮素浓度估算模型

[目的]快速、准确地诊断水稻叶片氮素营养状况,为水稻氮肥精准管理提供依据。[方法]以江西省农科院8种不同施肥处理的晚稻为研究对象,于主要生育期同步测定了水稻冠层光谱反射率及叶片全氮浓度(Leaf Nitrogen Concentration,LNC),系统分析了原始光谱反射率、一阶微分光谱、"三边"参数以及由350～1 350nm两两波段组合的差值(SD (Rλ1,Rλ2))、比值(SR (Rλ1,Rλ2))及归一化(ND(Rλ1,Rλ2))光谱指数与水稻LNC的相关关系,筛选出敏感参数,并以之为自变量构建了水稻LNC的传统预测模型,另外构建不同指标个数的多元线性与BP神经网络模型,并对模型进行验证。[结果](1)水稻LNC与一阶微分光谱在751nm处的相关性最高(r=0. 822);(2)"三边"参数中的红边面积SDr与LNC的相关性较高(r=0. 687);(3) 750nm附近的红边波段与近红外波段差值组合、550nm附近的绿光波段与近红外波段的比值及归一化差值组合与水稻LNC的相关性较高,以SD (R752,R751)、SR (R534,R1 350)和ND (R534,R1 349)表现最好,相关系数分别为0. 827、-0. 790和0. 788;(4)传统回归模型中以SD(R752,R751)构建的一元线性模型最佳(RC2=0. 665、RV2=0. 750、RMSEV=0. 4%、RPD=2. 034);(5)利用5个指标((R'751、SDr、SD (R752,R751)、SR (R534,R1 350)、ND (R534,R1 349))经逐步回归筛选出的2个指标SD ((R752,R751)和SR (R534,R1 350))构建预测水稻氮素的BP神经网络模型,预测效果最佳,其验证参数值分别为R2=0. 859、RMSEV=0. 302%和RPD=2. 669。[结论]基于单指标构建的传统线性模型计算过程简单但精度略低,而基于2个指标(SD (R752,R751)、SR (R534,R1 350))构建的BP神经网络模型预测精度高于该2指标构建的多元线性模型,表明在指标适合的情况下,BP神经网络对氮素具有较好的预测能力,是一种快速准确估算水稻叶片全氮浓度的方法。     

基于 BP 神经网络的结构损伤识别研究

针对结构的损伤识别进行了研究,选取结构固有频率平方变化比作为特征参数,建立12×25×1 BP网络结构,采用均方误差函数目标误差函数,学习函数选取梯度下降动量学习函数和L-M优化算法,对四层钢框架结构的损伤进行了检测。     

用神经网络对开式冷挤压极限变形程度的预测

给出了基于 BP网络的极限变形程度预测的分析方法 ,得到了开式冷挤压εmax神经网络计算结果 ,与实验结果比较 ,其精度较高 ,证明了神经网络模型在开式冷挤压工艺中应用的可行性。     

Free‐riding in multi‐party alliances: The role of perceived alliance effectiveness and peers' collaboration in a research consortium

Research summary : Multi‐party alliances rely on partners' willingness to commit and pool their efforts in joint endeavors. However, partners face the dilemma of how much to commit to the alliance. We shed light on this issue by analyzing the relationship between partners' free‐riding—defined as their effort‐withholding—and their perceptions of alliance effectiveness and peers' collaboration. Specifically, we posit a U‐shaped relationship between partners' subjective evaluations of alliance effectiveness and their free‐riding. We also hypothesize a negative relation between partners' perceptions of the collaboration of peer organizations and their free‐riding. Results from a mixed‐method study—combining regression analysis of primary data on a major inter‐organizational research consortium and evidence from two experimental designs—support our hypotheses, bearing implications for the multi‐party alliances literature. Managerial summary : Free‐riding is a major concern in multi‐party alliances such as large research consortia, since the performance of these governance forms hinges on the joint contribution of multiple partners that often operate according to different logics (e.g., universities, firms, and government agencies). We show that, in such alliances, partners' perceptions have relevant implications for their willingness to contribute to the consortium's shared goals. Specifically, we find that partners free‐ride more—that is, contribute less—when they perceive the effectiveness of the overall alliance to be either very low or very high. Partners also gauge their commitment to the alliance on the perception of the effort of their peers—that is, other organizations similar to them. These findings provide managers of multi‐party alliances with additional levers to motivate partners to contribute fairly to such joint endeavor. Copyright © 2015 John Wiley & Sons, Ltd.     

A study on the deployment of high-speed broadband networks in NUTS3 regions within the framework of digital agenda for Europe

This paper investigates the high-speed broadband situation in the EU and its prospects. It uses a deployment model to estimate the investment required to meet the Digital Agenda for Europe (DAE) broadband targets set by the European Commission in its Europe 2020 strategy at different stages: as of 2016, after expected operators’ deployment, after public subsidies and leveraged investment, and as expected in 2020. The model uses data at the NUTS3 level, which is the most granular level that has data available on the status of broadband deployment, to arrive at a coherent and comparable framework. From the different perspectives on the investment to meet DAE targets, the paper concludes on the need for an appropriate combination of incumbent and alternative operators investments, public subsidies and leveraged investments, and new investments, both public and private and non-existing as of 2016, examining their feasibility and the impact of different regulatory, technical, and policy strategies.     

40 years on: An account of innovation in the regulation of UK telecommunications,in 3½ chapters

The past nearly 40 years have seen major developments in telecommunications networks and services, and in how they are regulated. This paper describes innovations in UK telecommunications regulation which have taken place over the period, broken down into stages, beginning with the regulation of the former monopolist by an independent regulator under a price cap, continuing the regulation first of mobile and then, under European Directives, of copper-based broadband, and ending with the diffusion of fibre networks. It is argued that a variety of changes have reduced the scope of innovation over the period, including domestic institutional reform, the limits placed on later decisions by earlier ones (path dependency), and the constraining impact of European Union law and regulation. The paper concludes with some consideration of the effects on future innovation of the UK’s withdrawal from the EU.     

Why can collective action fail in Local Agri-food Systems? A social network analysis of cheese producers in Aculco,Mexico

Collective trademark and regional product qualification in food-processing industries have become a growing challenge for farmers in developing countries. This challenge is the target of collective action-based programs aiming at framing the cooperation context that would enable a local community to turn inherited resources and know-how into new market opportunities. Literature acknowledges that social capital is a crucial local resource for successful collective actions since it is a source of trust and collective commitment within a community. This paper deals with testing the role of this resource in the collective action case of the cheese producers in Aculco (Mexico). Focusing on the connectedness dimension of social capital, we propose an original methodology that relies on the multiplex and structural properties of social networks. This allows us to disentangle the opposite and ambivalent effects of social capital on the ability of a community to reach the goals assigned by the collective action program. Our empirical study shows that these critical properties can work in favor of adherence to collective action but can also create elite capture, clannish behaviors and entry barriers, thus showing a failure of collective action.     

矿井通风三维可视化系统及优化

系统建立了三维仿真框架,建立了三维空间属性模型和非空间属性模型,分别对空间数据和非空间数据进行储存和管理。并建立了Hardy-Cross迭代模型和离散反馈型神经网络模型优化通风网络模型。并以C#语言来实现系统的功能。     

Macro-Networks: An application to euro area financial accounts

This paper develops a financial network, designated the “Macro-Network”, that depicts the connections between the main financial and non-financial sectors of the economy in the various financial instruments of the euro area. The Macro-Network comprises of linkages across financial and non-financial sectors in each country. These country-level sector networks are then connected by the cross-border links between the individual banking sectors. Using the Macro-Network to simulate financial shocks, we find that the propagation effects depend on the underlying network structure, which evolves over time. After the financial crisis, bilateral linkages contracted sharply, reflecting the surge in counterparty risk and the de-leveraging processes. Nonetheless, our analysis suggests that even after this process, vulnerabilities remained in the euro area financial system, while a more diversified portfolio of cross-border exposures might mitigate the shock effects. We identify sectors which are most relevant for the propagation of financial shocks in the Macro-Network.