基于拓扑网络的江淮城市群通达性分析

江淮城市群是安徽省域经济发展重点区域,通达性是衡量城市群内在联系的重要指标。文章基于江淮城市群境内高等级公路拓扑网络图,对该区域的通达性特征进行分析。结果表明：江淮城市群整体通达性水平良好,各城市间通达程度存在明显差异,天然地理障碍对城市通达性的影响较为明显。     

星间链路技术的研究现状与发展趋势

星间链路技术是提高全球卫星导航系统的精度和自主导航能力的一项关键技术。介绍了全球主要卫星导航系统星间链路的建设情况,综述了国内外关于星间链路的重要研究,包括星座的特性分析、星间链路的构建准则、星间链路的拓扑分析、星间链路传播信号的设计以及星间链路信号的发射和接收等,指出了目前研究的侧重点,展望了星间链路的发展趋势和未来的研究方向。相关内容可为星间链路的进一步研究提供参考。     

Beyond Circular Thinking: Geographies of Transit‐Oriented Development

Transit‐oriented development (TOD) plays a significant role within contemporary planning policies for ‘smart growth’ and sustainable development, particularly in Europe and North America. As a well‐rehearsed practice, this planning model is due for critical assessment and improvement in terms of its ability to incorporate dynamic and heterogeneous socio‐spatial processes as matters of concern. Analyses of the conditions for ‘making TOD work’ in the scholarly and professional literatures tend to focus on the ‘node’ and ‘place’ qualities. While elaborations on node analysis (primarily based on accessibility measurements) abound within empirical research, discussions of place‐specific assets are limited in scope and often spatially bounded by the circle defined by a 10‐minute walk. This essay examines the use of this generic ‘circle’ model, and how it normatively frames how place is understood in TOD studies. We argue that the circle enhances a Euclidean understanding of the site, which favours a static and homogeneous spatial analysis of accessibility and density rather than (other) place qualities relating to dynamic socio‐spatial processes. Finally, we argue that relational geography can facilitate an analysis of place qualities beyond the circle—one in which both the continuities and shifting settings of the wider context are meaningfully taken into consideration.     

Bourdieu Comes to Town: Pertinence,Principles, Applications

This article frames the themes of the two‐part Interventions section ‘Bourdieu Comes to Town’. I first establish the pertinence of Bourdieu's sociology for students of the city by revisiting his youthful work on power, space, and the diffusion of urban forms in provincial Béarn and colonial Algeria. In both cases, urbanization is the key vector of transformation, and the city, town, or camp the site anchoring the forces dissolving the social fabric of the French countryside and overturning French imperialism in North Africa. These early studies establish that all social and mental structures have spatial correlates and conditions of possibility; that social distance and power relations are both expressed in and reinforced by spatial distance; and that propinquity to the center of accumulation of capital (economic, military, or cultural) is a key determinant of the force and velocity of social change. Next, I discuss four principles that undergird Bourdieu's investigations and can profitably drive urban inquiry: the Bachelardian moment of epistemological rupture, the Weberian invitation to historicize the agent (habitus), the world (social space) and the categories of the analyst (epistemic reflexivity); the Leibnizian‐Durkheimian imperative to deploy the topological mode of reasoning; and Cassirer's command to heed the constitutive efficacy of symbolic structures. The plasticity and productivity of his concepts suggest that Bourdieu can not only energize urban inquiry but also merge it into a broader analytic of the trialectic of symbolic division, social space, and the built environment. This paves a pathway for reconceptualizing the urban as the domain of accumulation, differentiation and contestation of manifold forms of capital, which makes the city a central ground, product, and prize of historical struggles.     

一种新颖的无人机编队拓扑形成与信道接入机制

针对全球导航卫星系统（Global Navigation Satellite System,GNSS）高精度相对定位的无人机编队飞行应用中的信息交互与通信时延问题，首先优化设计了编队飞行网络拓扑，实现所有成员的信息交互且通信代价最小；其次，基于优化设计的网络，提出一种新的通信信道接入机制；最后对16机编队飞行场景进行了仿真分析，评估通信网络及相对定位性能。结果表明，编队成员端到端通信时延小于20 ms，且当通信与载波相位差分处理的总时延小于相对位置感知时间间隔时，相对位置感知精度可达到亚分米级，且感知误差与时延和载体运动状态相关。     

Study on the evolutionary optimisation of the topology of network control systems

Computer networks have been very popular in enterprise applications. However, optimisation of network designs that allows networks to be used more efficiently in industrial environment and enterprise applications remains an interesting research topic. This article mainly discusses the topology optimisation theory and methods of the network control system based on switched Ethernet in an industrial context. Factors that affect the real-time performance of the industrial control network are presented in detail, and optimisation criteria with their internal relations are analysed. After the definition of performance parameters, the normalised indices for the evaluation of the topology optimisation are proposed. The topology optimisation problem is formulated as a multi-objective optimisation problem and the evolutionary algorithm is applied to solve it. Special communication characteristics of the industrial control network are considered in the optimisation process. In respect to the evolutionary algorithm design, an improved arena algorithm is proposed for the construction of the non-dominated set of the population. In addition, for the evaluation of individuals, the integrated use of the dominative relation method and the objective function combination method, for reducing the computational cost of the algorithm, are given. Simulation tests show that the performance of the proposed algorithm is preferable and superior compared to other algorithms. The final solution greatly improves the following indices: traffic localisation, traffic balance and utilisation rate balance of switches. In addition, a new performance index with its estimation process is proposed.     

The Only Way Is Up? Ordinary Topologies of Ramallah

This article seeks to conceptualize and value some of the quotidian geographies responsible for contemporary forms of urban change. The starting point for the argument is an attempt to account for recent urban change in the Palestinian city of Ramallah, particularly the proliferation of apartment buildings, using emerging work on verticality. It is argued that work on verticality focuses empirically on prominent cities and spaces of violent conflict, invokes the vertical as politically suspect and offers a theorization of space that is topographical in nature. Consequently, accounts of verticality have produced narratives that obscure topological spatial relations. This article seeks to make space for such topologies, which it is argued are crucial to producing urban and political life itself in many contexts. The concept of ordinary topologies is proposed as a means of attending to the complex and undervalued practices that are thought to be normal (but not static) and common within and across intensive or qualitative spatio‐temporal relations. This approach is fleshed out through a discussion of changing topographic–topological landscapes in Ramallah. In particular, it is argued that the increasingly verticalized landscape of the city, embodied in rapidly proliferating apartment buildings, must be understood in relation to frequent journeys to other places and changing family relations.     

价值流拓扑：一个全新的营销策略建模路径

研究以价值流概念阐明营销管理的实质并在此新的视角下统合微观营销与宏观营销.以价值流拓扑形成营销策略空间,也为营销建模与创新提供了一个新的分析框架和营销战略建模、优化的路径.本规范研究对框架的构建主要依赖演绎推理的方法,研究结果可以广泛应用于已存在的各类营销组织(营利及非营利)中,为提升营销效率、应对当今复杂多变的市场环境提供可行的理论指导.     

MAC子层帧格式与网络拓扑结构研究

网络拓扑结构是网络中各个站点相互连接的方式,本文在研究网络拓扑结构的基础上,进一步对总线型网络、令牌总线网、令牌环形网中的MAC子层帧格式进行了研究,并列举了MAC子层帧在网络传输中的应用实例。