Load-Aware Traffic Control in Software-Defined Enterprise Wireless Local Area Networks

With the growing popularity of Bring Your Own Device (BYOD), modern enterprise Wireless Local Area Networks (WLANs) deployments always consist of multiple Access Points (APs) to meet the fast-increasing demand for wireless access. In order to avoid network congestion which leads to issues such as suboptimal Quality of Service (QoS) and degraded user Quality of Experience (QoE), intelligent network traffic control is needed. Software Defined Networking (SDN) is an emerging architecture and intensively discussed as one of the most promising technologies to simplify network management and service development. In the SDN architecture, network management is directly programmable because it is decoupled from forwarding layer. Leveraging SDN to the existing enterprise WLANs framework, network services can be flexibly implemented to support intelligent network traffic control. This thesis studies the architecture of software-defined enterprise WLANs and how to improve network traffic control from a client-side and an AP-side perspective. By extending an existing software-defined enterprise WLANs framework, two adaptive algorithms are proposed to provide client-based mobility management and load balancing. Custom protocol messages and AP load metric are introduced to enable the proposed adaptive algorithms. Moreover, a software-defined enterprise WLAN system is designed and implemented on a testbed. A load-aware automatic channel switching algorithm and a QoS-aware bandwidth control algorithm are proposed to achieve AP-based network traffic control. Experimental results from the testbed show that the designed system and algorithms significantly improve the performance of traffic control in enterprise WLANs in terms of network throughput, packet loss rate, transmission delay and jitter

Fast Distributed Approximation for Max-Cut

Finding a maximum cut is a fundamental task in many computational settings. Surprisingly, it has been insufficiently studied in the classic distributed settings, where vertices communicate by synchronously sending messages to their neighbors according to the underlying graph, known as the $\mathcal{LOCAL}$ or $\mathcal{CONGEST}$ models. We amend this by obtaining almost optimal algorithms for Max-Cut on a wide class of graphs in these models. In particular, for any $\epsilon > 0$, we develop randomized approximation algorithms achieving a ratio of $(1-\epsilon)$ to the optimum for Max-Cut on bipartite graphs in the $\mathcal{CONGEST}$ model, and on general graphs in the $\mathcal{LOCAL}$ model. We further present efficient deterministic algorithms, including a $1/3$-approximation for Max-Dicut in our models, thus improving the best known (randomized) ratio of $1/4$. Our algorithms make non-trivial use of the greedy approach of Buchbinder et al. (SIAM Journal on Computing, 2015) for maximizing an unconstrained (non-monotone) submodular function, which may be of independent interest

Brave New Wireless World: Mapping the Rise of Ubiquitous Connectivity from Myth to Market

This dissertation offers a critical and historical analysis of the myth of ubiquitous connectivity—a myth widely associated with the technological capabilities offered by “always on” Internet-enabled mobile devices like smartphones and tablets. This myth proclaims that work and social life are optimized, made more flexible, manageable, and productive, through the use of these devices and their related services. The prevalence of this myth—whether articulated as commercial strategy, organizational goal, or mode of social mediation—offers repeated claims that the experience and organization of daily life has passed a technological threshold. Its proponents champion the virtues of the invisible “last mile” tethering individuals (through their devices) primarily to commercial networks. The purpose of this dissertation is to uncover the interaction between the proliferation of media artifacts and the political economic forces and relations occluded by this myth. To do this, herein the development of the BlackBerry, as a specific brand of devices and services, is shown to be intimately interrelated with the myth of ubiquitous connectivity. It demonstrates that the BlackBerry is a technical artifact whose history sheds light on key characteristics of our media environment and the political economic dynamics shaping the development of other technologies, workforce composition and management, and more general consumption proclivities. By pointing to the analytic significance of the BlackBerry, this work does not intend to simply praise its creators for their technical and commercial achievements. Instead, it aims to show how these achievements express a synthesis that represents the motivations of economic actors and prevailing modes of thought most particularly as they are drawn together in and through the myth of ubiquitous connectivity. The narrative arc of this dissertation is anchored by moments of harmonization among political economic interests as these shape (and are shaped by) prevailing modes of producing and relating through ubiquitous connectivity

Edge Computing for Extreme Reliability and Scalability

The massive number of Internet of Things (IoT) devices and their continuous data collection will lead to a rapid increase in the scale of collected data. Processing all these collected data at the central cloud server is inefficient, and even is unfeasible or unnecessary. Hence, the task of processing the data is pushed to the network edges introducing the concept of Edge Computing. Processing the information closer to the source of data (e.g., on gateways and on edge micro-servers) not only reduces the huge workload of central cloud, also decreases the latency for real-time applications by avoiding the unreliable and unpredictable network latency to communicate with the central cloud

Testing The Impact Of Training With Simulated Scenarios For Information Security Awareness On Virtual Community Of Practice Members

Information security has become a major challenge for all private and public organizations. The protection of proprietary and secret data and the proper awareness of what is entailed in protecting this data are necessary in all organizations. This treatise examines how simulation and training would influence information security awareness over time in virtual communities of practice under a variety of security threats. The hypothesis of the study was that security-trained members of a virtual community of practice would respond significantly better to routine security processes and attempts to breach security or to violate the security policy of their organization or of their virtual community of practice. Deterrence theory was used as the grounded theory and integrated in the information security awareness training with simulated scenarios. The study provided training with simulated scenarios and then tested the users of a virtual community of practice over an approximately twelve-week period to see if the planned security awareness training with simulated security problem scenarios would be effective in improving their responses to the follow-up tests. The research subjects were divided into four groups, the experimental group and three control groups. The experimental group received all of the training and testing events throughout the twelve-week period. The three control groups received various portions of the training and testing. The data from all of the tests were analyzed using the Kruskal-Wallis iv ranked order test, and it was determined that there was no significant difference between the groups at the end of the data collection. Even though the null hypothesis, which stated that there would be no difference between the groups scores on the information security awareness tests, was not rejected, the groups that received the initial training with the simulated scenarios did perform slightly better from the pre-training test to the post-training test when compared with the control group that did not receive the initial training. More research is suggested to determine how information security awareness training with simulated scenarios and follow-up testing can be used to improve and sustain the security practices of members of virtual communities of practice. Specifically, additional research could include: comparing the effect of training with the simulated scenarios and with training that would not use the simulated security scenarios; the potential benefits of using adaptive and intelligent training to focus on the individual subjects’ weaknesses and strengths; the length of the training with simulated scenarios events, the time between each training event, and the overall length of the training; the demographics of the groups used in the training, and how different user characteristics impact the efficacy of the training with simulated scenarios and testing; and lastly examining how increasing the fidelity of the simulated scenarios might impact the results of the follow-up tests

Organisations as complex adaptive systems : implications for the design of information systems

Today a paradigm shift in the field of organisation and management theories is no longer disputed and the need to switch from the Command-and-Control to the Leaming Organisation Paradigm (LOP) in the area of organisational theory is well understood. However, it is less well appreciated that learning organisations cannot operate effectively if supported by centralised databases and tailor-made application programs. LOP emphasises adaptability, flexibility, participation and learning. It is important to understand that the changes in organisational and management strategies will not on their own be able to produce the desired effects unless they are supported by appropriate changes in organisational culture, and by effective information systems. This research demonstrates that conventional information system strategies and development methods are no longer adequate. Information system strategies must respond to these needs of the LOP and incorporate new information systems that are capable of evolving, adapting and responding to the constantly changing business environment. The desired adaptability, flexibility and agility in information systems for LOP can be achieved by exploiting the technologies of the Internet, World Wide Web, intelligent agents and intranets. This research establishes that there is a need for synergy between organisational structures and organisational information systems. To obtain this desired synergy it is essential that new information systems be designed as an integral part of the learning organisational structure itself. Complexity theory provides a new set of metaphors and a host of concepts for the understanding of organisations as complex adaptive systems. This research introduces the principles of Complex Adaptive Systems and draws on their significance for designing the information systems needed to support the new generation of learning organisations. The search for new models of information system strategies for today's dynamic world of business points to the 'swarm models' observed in Nature

Dynamics in Logistics

This open access book highlights the interdisciplinary aspects of logistics research. Featuring empirical, methodological, and practice-oriented articles, it addresses the modelling, planning, optimization and control of processes. Chiefly focusing on supply chains, logistics networks, production systems, and systems and facilities for material flows, the respective contributions combine research on classical supply chain management, digitalized business processes, production engineering, electrical engineering, computer science and mathematical optimization. To celebrate 25 years of interdisciplinary and collaborative research conducted at the Bremen Research Cluster for Dynamics in Logistics (LogDynamics), in this book hand-picked experts currently or formerly affiliated with the Cluster provide retrospectives, present cutting-edge research, and outline future research directions

Conceptualizing the Electronic Word-of-Mouth Process: What We Know and Need to Know About eWOM Creation, Exposure, and Evaluation

Electronic word of mouth (eWOM) is a prevalent consumer practice that has undeniable effects on the company bottom line, yet it remains an over-labeled and under-theorized concept. Thus, marketers could benefit from a practical, science-based roadmap to maximize its business value. Building on the consumer motivation–opportunity–ability framework, this study conceptualizes three distinct stages in the eWOM process: eWOM creation, eWOM exposure, and eWOM evaluation. For each stage, we adopt a dual lens—from the perspective of the consumer (who sends and receives eWOM) and that of the marketer (who amplifies and manages eWOM for business results)—to synthesize key research insights and propose a research agenda based on a multidisciplinary systematic review of 1050 academic publications on eWOM published between 1996 and 2019. We conclude with a discussion of the future of eWOM research and practice