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991.
针对无线传感器中的节点调度传输问题,提出了一种基于网络编码的协同点对点信息交换算法。由于该算法不仅能够充分利用无线信道的广播特性,而且使用了协同点对点信息交换,从而有效地弥补了PIE算法在数据包的个数大于节点数目的情况下,性能不理想的缺陷,实现了传输次数的减少。仿真结果表明,所提算法的传输有效性明显地优于PIE算法和最少优先算法。  相似文献   
992.
面对着经济、科技全球一体化和军民融合式发展趋势,国防科技重大工程迫切需要进行有效的技术总成。本文首先结合国防科技重大工程的特点,在技术整合概念的基础上进一步深化提炼出了技术总成的概念,然后基于协同理论和网络组织理论,介绍了基于任务分解的国防重大科技工程组织协同网络模型的类型,最后根据不同类型模型的特征,构建了面向技术总成的两种国防科技重大工程组织协同网络模型。  相似文献   
993.
在就跨境电商对华商网络贸易所具有的替代效应与互补效应进行理论分析的基础上,利用古诺模型分析市场均衡的结果及贸易效应,采用面板数据实证检验跨境电商对华商网络贸易的影响,结果表明跨境电商对华商网络贸易的互补效应大于替代效应:一方面,由于华商网络对出口贸易的影响尤为显著,而跨境电商平台又以出口贸易为主,从而跨境电商对华商网络出口贸易的影响较大;另一方面,跨境电商平台偏向于差异化产品贸易,因而跨境电商对差异化产品的华商网络贸易有着较大影响。也就是说,跨境电商对华商网络贸易的互补效应在出口贸易与差异化产品贸易上表现得尤为显著。  相似文献   
994.
以A股地方国有上市公司为研究对象,从投资效率的角度考察国有资本经营预算制度的实施效果,并进一步检验其对企业价值的影响。研究发现,国有资本经营预算能够显著抑制地方国有企业的非效率投资,尤其是抑制过度投资行为,并且这种影响对处于市场化程度较低地区的地方国有企业更加显著。进一步研究发现,国有资本经营预算能够通过抑制非效率投资来促进地方国有企业价值的提升。  相似文献   
995.
随着存款保险制度的推出以及金融机构退出机制的完善,国家声誉将逐渐退出银行无形资本。在激励相容的金融监管趋势下,特许权价值等市场约束力量会显著影响到商业银行的风险承担。在此逻辑基础上,以我国16家上市商业银行为研究对象,一方面探讨特许权价值影响下不同产权结构的商业银行的最优救助机制,另一方面通过最优救助临界指标,利用银行重组模型,推导合理的存款保险风险差别费率。  相似文献   
996.
Research Summary: This study addresses a theoretical dilemma regarding how alliance network constraint (reflected by network cohesion) affects a firm’s alliance formation with new partners. Using a network pluralism approach, we separate a firm’s ego alliance network into two activity‐based networks—an exploratory network and an exploitative network—based on the primary value chain activity involved in each alliance. We argue that the cohesion of exploratory or exploitative networks has an inverted U‐shaped effect on the addition of new partners in the same activity‐based network, and a positive effect on the addition of new partners in the other network. Results based on data from the biotechnology industry largely support our predictions with one exception. Our study contributes to both scholarly understanding of network embeddedness and alliance practice. Managerial Summary: The structure of firms’ ongoing alliance networks may have paradoxical implications for their efforts to search for and form alliance with new partners. That is, when a firm’s alliance partners are tightly connected with each other, the cohesive network tends to both encourage and impede the focal firm to add new partners. We resolve this dilemma by showing that when a firm is deeply entrenched in a cohesive alliance network conducting a certain type of activities (e.g., R&D activities), it may not easily add new R&D alliance partners. However, it may still be able to escape from the cohesive R&D alliance network by seeking new partners conducting other activities (e.g., manufacturing activities).  相似文献   
997.
Research Summary: Research exploring investor reactions to sustainability has substantial empirical limitations, which we address with a large‐scale longitudinal financial event study of the first global sustainability index, DJSI World. We examine investor reactions to firms from 27 countries over 17 years that are added, deleted, or continue on the index. We find that once relevant controls and comparisons to observationally equivalent firms beyond the index are included, DJSI events have only limited significance and/or materiality. Nonetheless, investors' valuation of sustainability around the world has evolved over time, involving diminishing reactions to U.S. firms and increasing benefits, particularly of continuation on the index, over time. The study highlights the importance of careful analysis and longitudinal global samples in making inferences about the financial effects of social performance. Managerial Summary: The debate about how investors perceive corporate social responsibility (CSR) predates Milton Friedman's famous statement that the only social responsibility of business is to increase profits. Although extensive research has studied whether sustainability contributes to financial performance, we have yet to understand whether investors believe it pays off. This financial event study of reactions to the addition, continuation, and deletion from DJSI World, the first global sustainability index, shows that investors care little about DJSI announcements. Nonetheless, there is some evidence that global assessments of sustainability are converging and that investors may increasingly be valuing continuation on the DJSI, suggesting that firms may gain at least limited benefits from reliable sustainability activities.  相似文献   
998.
999.
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.  相似文献   
1000.
This study examines how venture capital (VC) firms terminate investments in an emerging economy context. We contend that due to the weak institutional environment, it is appropriate to draw on insights from power and social relation perspectives for a better understanding of the phenomenon. Specifically, we argue that a termination decision hinges on not only the dependence relationship between a VC firm and its portfolio companies, but also the social relationships among VC firms. Event history analyses of approximately 12,000 VC deals made in China between 2001 and 2012 reveal that when a VC firm has a greater number of investments in an industry, it is more likely to terminate investments on a portfolio company in that industry. Moreover, such effect on termination is moderated by the focal VC's embeddedness with its syndicate partners and collaboration opportunities with other VC firms outside the immediate access of the syndicate partners. Our study sheds light on research on VC decision making in emerging markets by integrating insights from resource dependence relationships and interorganizational network characteristics.  相似文献   
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