A Hierarchical Model of Supply-Chain Integration: Information Sharing and Operational Interdependence in the US Grocery Channel

This paper examines costs of and motivations for interconnectivity within the grocery supply chain, employing evidence from multiple case studies and survey data to develop a seven-level model of technology-enabled supply-chain connectivity and channel interdependence. This theoretical model, built around a modified transactions-costs framework, is illustrated using examples of processes that span multiple levels of interconnectivity and interdependence within the grocery channel between different groups of customers and suppliers. Our analysis suggests that while a discernible hierarchy of levels of IT-enabled interorganizational connectivity exists, not all relationships necessarily evolve to the highest level of virtual integration. Indeed, limits on executive attention preclude this level from being achieved by more than a small fraction of trading partners. The model generates eight testable hypotheses for further study.     

三维表面形貌的连通性表征

从集合的角度,运用图像描述方法,提出了三维表面形貌连通性表征的方法,建立了连通数、连通指数的概念以及相应的算法,并结合实际,模拟出一些特征明显的三维表面形貌,确定了评定表面连通性能的基准面,定量分析了表面形貌的连通性随表面高度的变化情况,比较出在传统的表面形貌参数相似的情况下表面连通性能的差异,为表面形貌表征研究开辟了一个新的途径.     

基于灰度级连通性的FLIR图像的目标检测方法

通过对灰度级连通性及其算法的分析,文中给出目标k级成分区域提取算法,并针对前视红外(FLIR)图像序列提出一种目标检测的新方法。这种方法分为帧内和帧间处理:帧内处理利用目标k级成分区域提取算法实现单帧目标检测,帧间处理利用目标时间连通性实现序列图像间的目标关联和目标检测。仿真结果表明:在噪声和杂波干扰下,所提出的方法对红外图像序列弱小目标检测是有效和稳健的。     

一种基于位置的WSN密钥管理方案

针对当前无线传感器网络（WSN）随机密钥预分布方案中网络只能概率连通且密钥不能作为认证的问题，文中提出了一种基于节点位置的密钥管理方案LBK-KMS，文中详细介绍LBK-KMS方案的建立过程；并从安全抵抗性，网络连通性，扩展性以及通信计算性能等方面与E-G以及q-Composite方案进行了比较分析；最后探讨了下一步可研究的工作．     

HYDROLOGIC CONNECTIVITY OF FLOODPLAINS,NORTHERN MISSOURI—IMPLICATIONS FOR MANAGEMENT AND RESTORATION OF FLOODPLAIN FOREST COMMUNITIES IN DISTURBED LANDSCAPES

Hydrologic connectivity between the channel and floodplain is thought to be a dominant factor determining floodplain processes and characteristics of floodplain forests. We explored the role of hydrologic connectivity in explaining floodplain forest community composition along streams in northern Missouri, USA. Hydrologic analyses at 20 streamgages (207–5827 km² area) document that magnitudes of 2‐year return floods increase systematically with increasing drainage area whereas the average annual number and durations of floodplain‐connecting events decrease. Flow durations above the active‐channel shelf vary little with increasing drainage area, indicating that the active‐channel shelf is in quasi‐equilibrium with prevailing conditions. The downstream decrease in connectivity is associated with downstream increase in channel incision. These relations at streamflow gaging stations are consistent with regional channel disturbance patterns: channel incision increases downstream, whereas upstream reaches have either not incised or adjusted to incision by forming new equilibrium floodplains. These results provide a framework to explain landscape‐scale variations in composition of floodplain forest communities in northern Missouri. Faust ( 2006 ) had tentatively explained increases of flood‐dependent tree species, and decreases of species diversity, with a downstream increase in flood magnitude and duration. Because frequency and duration of floodplain‐connecting events do not increase downstream, we hypothesize instead that increases in relative abundance of flood‐dependent trees at larger drainage area result from increasing size of disturbance patches. Bank‐overtopping floods at larger drainage area create large, open, depositional landforms that promoted the regeneration of shade‐intolerant species. Higher tree species diversity in floodplains with small drainage areas is associated with non‐incised floodplains that are frequently connected to their channels and therefore subject to greater effective hydrologic variability compared with downstream floodplains. Understanding the landscape‐scale geomorphic and hydrologic controls on floodplain connectivity provides a basis for more effective management and restoration of floodplain forest communities. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.     

A connectivity-preserving flocking algorithm for multi-agent systems based only on position measurements

Most existing flocking algorithms rely on information about both relative position and relative velocity among neighbouring agents. In this article, we investigate the flocking problem with only position measurements. We propose a provably-stable flocking algorithm, in which an output vector is produced by distributed filters based on position information alone but not velocity information. Under the assumption that the initial interactive network is connected, the flocking algorithm not only can steer a group of agents to a stable flocking motion, but also can preserve the connectivity of the interactive network during the dynamical evolution. Moreover, we investigate the flocking algorithm with a virtual leader and show that all agents can asymptotically attain a desired velocity even if only one agent in the team has access to the information of the virtual leader. We finally show some numerical simulations to illustrate the theoretical results.     

基于多维模式分析对说谎的脑网络特征识别

为了研究说谎时的脑网络特征,采集了32个被试在说真话和说谎条件下的功能磁共振数据,预处理后利用AAL模板构建不同条件下的功能连接网络,再利用基于机器学习的多维模式分类器对说谎和说真话进行分类。该分类器取得了良好的分类正确率82.03%(说谎84.38%,说真话79.69%),并提取了辨别说谎和说真话的有效的功能连接模式。结果表明了使用大尺度的功能连接对说谎和说真话进行分类的良好性能,并且从脑网络角度揭示了说谎的特征。     

物流运输网络连通可靠性分析的高效分解算法

可靠性分析是衡量物流运输网络运行服务水平的主要手段之一。给出了一种评估物流运输网络连通可靠性的高效分解算法,算法充分利用分解过程中获得的相关信息,通过引入保持网络可靠性不变的串联边化简、并联边化简以及节点合并等规则,并结合向量集分解方法,能够快速实现对网络状态向量空间的分解,达到提高网络可靠性评估效率的目的。实例分析以及和现有方法的比较验证了算法的性能和分解效率。     

Dynamic Connectivity for Axis-Parallel Rectangles

In this paper we give a fully dynamic data structure to maintain the connectivity of the intersection graph of n axis-parallel rectangles. The amortized update time (insertion and deletion of rectangles) is and the query time (deciding whether two given rectangles are connected) is O(1). It slightly improves the update time (O(n ^0.94)) of the previous method while drastically reducing the query time (near O(n ^1/3)). In addition, our method does not use fast matrix multiplication results and supports a wider range of queries. This work has been supported by an NSERC grant.     

Metabolism and Morphology

Architecture is on the cusp of systemic change, driven by the dynamics of climate and economy, of new technologies and new means of production. There is a growing interest in the dynamics of fluidity, in networks and in the new topologies of surfaces and soft boundaries. This is part of a general cultural response to the contemporary reconfiguration of the concept of ‘nature’ within the discourse of architecture; a change from metaphor to model, from ‘nature’ as a source of formal inspiration to ‘nature’ as a mine of interrelated dynamic processes that are available for analysis and digital simulation. Michael Weinstock presents an account of the dynamics of natural metabolisms, and suggests an agenda for the development of metabolic morphologies of buildings and cities. Copyright © 2008 John Wiley & Sons, Ltd.