Centralized Network Structure Research Articles

Improvement of Software-Defined Network Performance Using Queueing Theory: A Survey

Software-Defined Networking (SDN) is a growing network technology that has brought significant benefits to a wide range of disciplines, from science to technology to various fields. This structure can be used in network-based environments, data centers and various research sites. OpenFlow is one of the most widely used protocols for interaction between a controller and a switch in a Software-Defined Networking. Understanding the performance and limitations of the network defined by open source software, including bottlenecks and security vulnerabilities due to the centralized network structure, are important prerequisites for the efficient deployment of these systems. These points of view led researchers to examine various related mathematical models to address these issues. Queueing theory provides the most important and accurate model for evaluating the performance of the SDN networks affected by these restrictions, which has attracted the attention of researchers recently. Regarding to extensive mathematical modeling, this theory has also been used to improve network efficiency. Researchers have used this theory to investigate operational power and improve time consumption and control of data planes due to the nature of classification and storage of packets in SDN buffers. These methods overcome controller performance bottlenecks and increase SDN control capacity, especially for large distributed networks. In this paper, we examine the queueing models for different applications in different layers of SDN, in which researchers use these methods to monitor network loads, evaluate and predict performance changes due to diversity in network traffic. We introduce and review a collection of articles that explore, different applications of Queueing theory in SDN networks. In addition, in order to increase the efficiency of this research, detailed comparisons are performed in terms of structure, mathematical models and the final simulation results.

Cliques Role in Organizational Reputational Influence: A Social Network Analysis

Empirical support for the assumption that cliques are major determinants of reputational influence derives largely from the frequent finding that organizations which claimed that their cliques’ connections are influential had an increased likelihood of becoming influential themselves. It is suggested that the strong and consistent connection in cliques is at least partially responsible for the reputational influence factors. It is argued that social network analysis is an appropriate method for studying the use of influence development in the context of networked organizations. The results of the statistical network analysis reveal interesting findings in terms of prominent structural forms and the impact of involvement or embeddedness in the formal network. Consequently, this tells us that firms’ embeddedness in a centralized network structure which is based on formal ties harms the firms’ level of reputational influence.

The Impact of Network Centralization on Relational Capital

With an increasing degree of connections among firms forming network of economic activities, it is timely to assess the potential of these upon embedded firms. This article presents empirical evidence to that end. It distinguishes between decentralized and centralized network structure that illustrate the difficulties encountered in managing an inter-firm network structure. Although considerable studies has been performed in network issues affecting firms performance, very few research analyse the complicating attributes of a centralized network structure on its effects on firms performance. Thus this article described different attributes of the centralized network and its effects on firms’ relational capital outcomes. Using social network analysis methodology this study found that certain structural position occupied by firms in network impacts on its relational capital outcome. This study is significant as it’s contributed to prudent management of resources in managing complex network structure. Future research is also discussed.

Uplinks Analysis and Optimization of Hybrid Vehicular Networks

5G vehicular communication is one of key enablers in next generation intelligent transportation system (ITS), that require ultra-reliable and low latency communication (URLLC). To meet this requirement, a new hybrid vehicular network structure which supports both centralized network structure and distributed structure is proposed in this paper. Based on the proposed network structure, a new vehicular network utility model considering the latency and reliability in vehicular networks is developed based on Euclidean norm theory. Building on the Pareto improvement theory in economics, a vehicular network uplink optimization algorithm is proposed to optimize the uplink utility of vehicles on the roads. Simulation results show that the proposed scheme can significantly improve the uplink vehicular network utility in vehicular networks to meet the URLLC requirements.

On the features of Software Defined Networking for the QoS provision in data networks

Introduction: The traditional networks mostly implement devices where the control plane is distributed and mixed with the data plane; this fact does not allow a fast evolution towards a process that contributes to improving the transport of services. Otherwise, Software Defined Networking is a set of transport services that optimize the use of resources as these have a centralized network structure.
 Objective: To determine the aspects that enable software-defined networking to provide quality of service features in data networks.
 Methodology: This study is performed through network simulation over the same base network and under the same working conditions by carrying out measurements of the packet forwarding response time and management of the transported bandwidth. This study includes the demonstration of the multimedia content transport over a network architecture defining priorities to the links.
 Results: The outcomes show how the Software Defined Networking achieves better management of data transmission through the base network. In the same way, the previous outcomes are reinforced with those obtained in the quality of service test performed on the streaming of a multimedia flow.
 Conclusions: Due to the centralized control of Software Defined Networking, forwarding functions with the quality of service features are enabled in data networks based on layer-2 devices.

Social network evolution in creative process of CNPD teams: a case study of Chinese companies

The existing theories about how social networks affect creativity mostly focus on a certain stage in the organizational life of an idea, for instance, ideas generation, commercialization of ideas, and a previous assumption refers that multiple attributes of social networks of creative team are static. It is not possible to resolve such a realistic and important issue that how dynamic evolution of social networks affects the creative process at the fuzzy front-end of complex new product development (CNPD) of research and development (RD homogeneity of task knowledge, strong-tie network relationship, and centralized network structure are good for idea screening; homogeneity of task knowledge in the network is maintained while new knowledge is obtained actively from the outside; internal network relationship is dominated by strong tie while weak tie is connected with the outside; both diffused and balanced network structures are beneficial to idea development.

A Systems Theory Approach to the District Central Office's Role in School-Level Improvement

This qualitative case study used General Systems Theory and social network analysis to explore the relationships between the members of a district central office and principals of elementary schools within an urban school district in the Midwest. Findings revealed sparse relationships between members of the district central office and principals, more opportunities for higher performing schools to participate in decision making, and few opportunities for all schools to provide feedback to the district, resulting in a centralized network structure that may inhibit the transfer of knowledge and communication, and ultimately, hinder school-level improvement efforts. Keywords: systems theory, social network analysis, district central office, reform

The Ebb and Flow of Social Network Ties Between District Leaders Under High-Stakes Accountability

Recent scholarship suggests the importance of school district offices in supporting reform. These studies provide strategies for building relations between central offices and sites in order to improve change efforts. However, what is frequently overlooked is that organizational reform efforts are socially constructed. Therefore, examining the underlying reform-related social networks may provide insight into how relational structures support or constrain efforts at reform. This longitudinal case study draws upon social network analysis and interviews to examine the reform-related knowledge, advice, and innovation network structures of central office and site leaders in a district facing sanction for underperformance and engaging a districtwide reform. Findings indicate that over time, the networks increased the number of superficial interactions, and more frequent exchanges remained unchanged, resulting in a centralized network structure.

A bridge between worlds: understanding network structure to understand change strategy

A number of scholars are exploring district and site relations in organizational change efforts in the larger policy context of No Child Left Behind. These studies suggest the importance of the central office as a support to the work of reform and offer strategies for building relations between district offices and sites in order to implement and sustain change efforts. What is frequently overlooked in these studies is that organizational change efforts are often socially constructed. Therefore, examining the underlying social networks may provide insight into structures that support or constrain efforts at change. This exploratory case study uses social network analysis and interviews to examine the communication and knowledge network structures of central office and site leaders in an ‘in need of improvement’ district facing sanctions under No Child Left Behind. Findings indicate sparse ties among and between school site and central office administrators, as well as a centralized network structure that may constrain the exchange of complex information and ultimately inhibit efforts at change.

A bi-objective reverse logistics network analysis for post-sale service

Reverse logistics, induced by various forms of return, has received growing attention throughout this decade. Reverse logistics network design is a major strategic issue. This paper addresses the analysis of reverse logistic networks that deal with the returns requiring repair service. A problem involving a manufacturer outsourcing to a third-party logistics (3PLs) provider for its post-sale services is proposed. First, a bi-objective optimization model is developed. Two objectives, minimization of the overall costs and minimization of the total tardiness of cycle time, are addressed. The facility capacity option at each potential location is treated as a discrete parameter. The purpose is to find a set of non-dominated solutions to the facility capacity arrangement among the potential facility locations, as well as the associated transportation flows between customer areas and service facilities. Then, a solution approach is designed for solving this bi-objective optimization model. The solution approach consists of a combination of three algorithms: scatter search, the dual simplex method and the constraint method. Finally, computational analyses are performed on trial examples. Numerical results present the trade-off relationship between the two objectives. The numerical results also show that the optimization for the first objective function leads to a centralized network structure; the optimization for the second objective function results in a decentralized network structure.

Electronic Word-of-Mouth in Online Environments

ABSTRACTThis article presents a network analysis of electronic word-of-mouth referral communication in a real life online environment. The goal of the paper was to clarify the existing terminology of electronic word-of-mouth behavior, to examine the kind of network structure that will emerge in the electronic environment, and finally to explore the impact of the network structure on the acceptance of an innovation in such a communication environment. Results indicated that the structure of an electronic communication network is different from the traditional interpersonal communication network structure. This study also showed that the network structure affects innovation adoption timing in the electronic communication environment, as a centralized network structure leads towards early adoption and as tie strength and adoption timing are related.

Knowledge sharing community in P2P network: a study of motivational perspective

How to effectively share knowledge within organizations has been given a great deal of attention in practice as well as in research. However, most of current approaches are based on the centralized network structure, e.g. a central knowledge repository, which has been considered inappropriate and ineffective to facilitate the process of knowledge sharing. On the contrary, in this study, we propose the idea of a virtual knowledge sharing community that is based on decentralized P2P technology. In the community, each member plays an equal role of knowledge producing, receiving and coordinating. We believe that decentralized P2P has many distinct advantages in knowledge sharing. Moreover, referring to relevant psychological studies on human motivation, four application features for the virtual knowledge sharing community are further proposed. After being applied, each of the features is believed to have capability of motivating the members of community to share knowledge with each other.