Editorial introduction: The power of words and networks

According to Freud “words were originally magic and to this day words have retained much of their ancient magical power”. By words, behaviors are transformed and problems are solved. The way we use words reveals our intentions, goals and values. Novel tools for text analysis help understand the magical power of words. This power is multiplied, if it is combined with the study of social networks, i.e. with the analysis of relationships among social units. This special issue of the International Journal of Information Management, entitled “Combining Social Network Analysis and Text Mining: from Theory to Practice”, includes heterogeneous and innovative research at the nexus of text mining and social network analysis. It aims to enrich work at the intersection of these fields, which still lags behind in theoretical, empirical, and methodological foundations. The nine articles accepted for inclusion in this special issue all present methods and tools that have business applications. They are summarized in this editorial introduction.     

Telecommunications and information networks: Growing international tensions and their underlying causes

Abstract

This article explores the growing international tensions over information networks and the conflict related to the underlying telecommunications networks that lies at the heart of the matter. Telecommunications policy and practice is changing significantly in many countries and at the international level. Tensions and conflict are identified as taking place on four levels: conflict over underlying values, conflict between and among different industry groups, political conflict among nations, and an emerging trade politics related to the application of services trade principles and rules to telecommunications and information services. These levels of tension/conflict should not be treated as distinct and mutually exclusive, but rather as overlapping and interactive, emphasizing the complex and increasingly serious nature of this important issue.     

A new mathematical analysis of series and shunt faults on three phase power networks

A mathematical analysis of sequential fault transients due to series and shunt faults is important in the study of circuit breaker pole openings and reclosings with arc resistances. The line loading itself becomes unbalanced momentarily due to load switching. Each double fault is developed in sequence, therefore the initial currents in the second and third fault must be treated properly under transient conditions. New sequence component variables λμ0 and ρσ0 are used with αβ0 components. This study is useful for small power systems as well for large power systems. A digital simulation of various series and shunt faults is presented in a generalized manner using αβ0, λμ0 and ρσ0 components.     

Integrated base station assignment,diversity and power control for cognitive radio networks

An integrated base station assignment, diversity and power control algorithm is proposed to realize the base station sharing, in which primary users (PUs) and secondary users (SUs) can connect to any base station by the variable base station assignment, so that the radio resource is efficiently utilized for cognitive radio networks. We show that this algorithm reduces SU's outage rate (for failing to meet the requirement of SINR per bit) while always meeting the requirement of SINR per bit for all PUs.     

复杂网络理论在组织网络研究中的应用

本文通过分析复杂网络的结构特征及其内在嵌入性机理,回顾了复杂网络的基本理论现状。然后,分析得到了组织网络的非线性、多模块特征,发现了组织网络与复杂网络共同的行为模式。据此,将复杂网络引入到组织网络的研究中来,分别从组织网络的表示方法与分析手段,组织网络的互动关系和程度对其鲁棒性和适应性的影响,组织网络内在的协调机理,以及其局部互动与全局演化动力学特征之间的关系等几个方面探讨了复杂网络理论在组织网络研究中的应用前景。     

Multi-layer self-organizing polynomial neural networks and their development with the use of genetic algorithms

In this paper, we introduce a new architecture of genetic algorithms (GA)-based self-organizing polynomial neural networks (SOPNN) and discuss a comprehensive design methodology. Let us recall that the design of the “conventional” PNNs uses an extended group method of data handling (GMDH) and exploits polynomials (such as linear, quadratic, and modified quadratic functions) as well as considers a fixed number of input nodes (as being selected in advance by a network designer) at polynomial neurons (or nodes) located in each layer. The proposed GA-based SOPNN gives rise to a structurally optimized structure and comes with a substantial level of flexibility in comparison to the one we encounter in conventional PNNs. The design procedure applied in the construction of each layer of a PNN deals with its structural optimization involving the selection of preferred nodes (or PNs) with specific local characteristics (such as the number of input variables, the order of the polynomial, and a collection of the specific subset of input variables) and addresses specific aspects of parametric optimization. An aggregate performance index with a weighting factor is proposed in order to achieve a sound balance between approximation and generalization (predictive) abilities of the network. To evaluate the performance of the GA-based SOPNN, the model is experimented with using chaotic time series data. A comparative analysis reveals that the proposed GA-based SOPNN exhibits higher accuracy and superb predictive capability in comparison to some previous models available in the literature.     

The regulation of telecommunications networks

Abstract

In the past several years, the number of sellers from whom customers of telecommunications network services can choose has increased dramatically. Whether it is the provision of domestic long‐distance service, or the offering of international telecommunications, or even the delivery of local communications, where previously service was provided by one firm or by a stable handful of firms that shared a market, users now have a wider range of choice and this increase in the scope of choice is likely to continue into the future. These changes, the result of a combination of developments in technology and regulatory policy, have created new problems for those charged with the regulation of telecommunications.

This paper begins by tracing the changes in regulatory policy that have led to the increase in the number of suppliers of domestic long‐distance telecommunications service. Then, it examines a number of principles for pricing telecommunications network services. Next, it identifies a number of explanations that have been offered for the proliferation in network services that has occurred. It then attempts to draw lessons from developments in the long distance market for the future of local network service. Finally, the paper explores the difficulties that policy‐makers will face in the new, more competitive environment.     

Extracting the hydrodynamic resistance of droplets from their behavior in microchannel networks

The overall traffic of droplets in a network of microfluidic channels is strongly influenced by the liquid properties of the moving droplets. In particular, the effective hydrodynamic resistance of individual droplets plays a key role in their global behavior. Here we propose two simple and low-cost experimental methods for measuring this parameter by analyzing the dynamics of a regular sequence of droplets injected into an “asymmetric loop” network. The choice of a droplet taking either route through the loop is influenced by the presence of previous droplets that modulate the hydrodynamic resistance of the branches they are sitting in. We propose to extract the effective resistance of a droplet from easily observable time series, namely, from the choices the droplets make at junctions and from the interdroplet distances. This becomes possible when utilizing a recently proposed theoretical model based on a number of simplifying assumptions. Here we present several sets of measurements of the hydrodynamic resistance of droplets, expressed in terms of a “resistance length.” The aim is twofold: (1) to reveal its dependence on a number of parameters, such as the viscosity, the volume of droplets, their velocity as well as the spacing between them. At the same time (2), by using a standard measurement technique, we compare the limitations of the proposed methods. As an important result of this comparison, we obtain the range of validity of the simplifying assumptions made in the theoretical model.     

A cognitive TV white space-broadband power line MIMO system for indoor communication networks

Broadband power line communication (BPLC) is a promising solution to satisfy the growing data rate demands for broadband indoor communication networks. However, the BPLC transmission power spectral density (PSD) is restricted in the very high frequency (VHF) band to avoid harmful interference to the existing wireless services. In this paper, a new hybrid system is proposed utilizing BPLC and cognitive radio over TV white space (TVWS) to enhance the system capacity over BPLC in VHF, forming a VHF TVWS BPLC multiple-input multiple-output (MIMO) system. An iterative precoding algorithm is proposed to satisfy the interference limit at the TV primary user (PU) receiver (Rx) and enhance the ergodic capacity. Moreover, a power allocation algorithm is developed for the MIMO system to achieve the maximum ergodic capacity subject to the average total power constraint and limit of interference to TV PU. Simulation results demonstrate the significant enhancement in the achieved capacity by our proposed system in the VHF band compared to both previous cognitive and hybrid BPLC systems.     

A fuzzy control framework for interconnected nonlinear power networks under TDS attack: Estimation and compensation

This article focuses on time delay switch (TDS) attacks on power networks subject to highly nonlinear and interconnection. T–S model is utilized to represent each nonlinear power subsystem in the network. In order to attenuate adverse impacts from TDS attacks, a novel control technique of estimation and compensation is proposed. Combined with the method of finite time boundedness (FTB), transient stability of power systems could be achieved. First, an augmented fuzzy observer is constructed to capacitate a synchronous estimation for system states and TDS attacks, which ensures that the estimation error is limited via the intersection operation of ellipsoids within a specified finite time interval. Then, a compensation technique is employed to attenuate the influence from TDS attacks. Finally, simulation results of a distributed power network show the efficacy of the proposed method against TDS attacks.     

The social networks of collaborative process

We present a study exploring the connection between social networks and collaborative process. We focus on exploring academics' network position and its effect on their collaborative networks. In this paper, we discuss two types of networks of collaboration—(i) citation; and, (ii) co authorship. We explore the effects of social networks on these two types of collaborative process. By defining network position in this way, we develop a social network that uses the academics as nodes within the network instead of each published paper. We obtained the collaboration data through archival records (i.e. Web of Science) and examined the interactions among different actors from the archival records for determining the existence and strength of relations between actors.     

自来水厂供电稳定性浅析

供电稳定可靠是自来水厂正常生产的关键。提升水厂供电可靠性可从以下几方面考虑:供电回路设计,母线设计,用电设备的技术水平与质量水平,管理制度与操作规程等。文章从这几方面论述如何提升水厂的供电可靠性。     

Adaptive synchronization of complex dynamic networks with switching parameters subject to state constraints in power system

This paper deals with the synchronization control of power complex networks with switching parameters. In the meantime, the node state constraints are considered during the synchronization process. Admittedly, synchronization problem encountered in power complex networks is becoming progressively important due to the increasing connection and disconnection operations resulting from sustainable energy and controllable load. Hereon, the network model considering switching parameters of each node is established to describe the topology variation of power systems that may be confronted in practical terms. Then, by utilizing the adaptive backstepping technique with a barrier Lyapunov function (BLF), a novel synchronization controller is constructed recursively which accomplishes the nodes full states tracking within the predefined transient behavior. Owing to the characteristic of BLF, the designed controller as well as its adaptive law could guarantee both the constrained state of each node restricted by a prescribed range and the synchronization performance. Meanwhile, the bounded output of the system could track the desired trajectory. Finally, scenario simulations are performed to demonstrate the effectiveness and superiority of the proposed method.     

“学术权力”和“行政权力”融合对学术资源配置的影响效应分析——基于国家社科基金立项项目的实证研究

基于高校学术行政化趋势的加深,选取2008年和2014年共5 128项国家社科基金立项项目数据及主持人信息为样本,从"行政化教师"角度出发,利用多元有序Probit模型和倾向得分匹配方法(PSM)实证研究了"双权融合"对学术资源配置的影响。结果显示,probit估计发现在控制自身禀赋后,"双权"会对资源配置产生正向显著影响,倾向得分匹配法发现"双权"会达到约11%的影响效应。研究还发现,行政权力获得优质学术资源概率相较学术权力要高出约3%,但呈现疲软态势;随着行政级别的提升,"双权"对资源的影响程度会趋于加强,且越高级别资源这种趋势会越显著。