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Dissertations / Theses on the topic 'Critical network'
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Holifield, Gregory. "CHARACTERIZATION OF CRITICAL NETWORK COMPONENTS OF COUPLED OSCILLATORS." Doctoral diss., University of Central Florida, 2006. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2691.
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This dissertation analyzes the fundamental limits for the determination of the network structure of loosely coupled oscillators based on observing the behavior of the network, specifically, node synchronization. The determination of the requisite characteristics and underlying behaviors necessary for the application of a theoretical mechanism for determining the underlying network topology in a network of loosely coupled natural oscillators are the desired outcome. To that end, this effort defines an analytical framework where key components of networks of coupled oscillators are isolated in order to determine the relationships between the various components. The relationship between the number of nodes in a network, the number of connections in the network, the number of connections of a given node, the distribution of the phases of the network, and the resolution of measurement of the components of the network, and system noise is investigated.Ph.D.
School of Electrical Engineering and Computer Science
Engineering and Computer Science
Computer Engineering
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Shepherd, S. C. "Understanding networks : an examination of doctor engagement in a clinical network : the case of Mid Trent Critical Care Network." Thesis, Nottingham Trent University, 2015. http://irep.ntu.ac.uk/id/eprint/27718/.
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Within the field of health care, this study has addressed a lack of current research exploring social aspects of a clinical network. In presenting the final stage of this study, this document focusses on the engagement experience from a medical viewpoint. This is topical and of interest, as doctor engagement in the NHS is associated with enhanced organisational performance and improved patient care. There is little previous empirical research exploring the engagement experience from the perspective of doctors working in a clinical network. The final stage of this research study therefore presents a new theoretical understanding of this subject area. Throughout the study, the author has demonstrated that clinical engagement is at the heart of a successful clinical network. The study is qualitative in nature and takes an interpretive epistemological orientation. Data is gathered through a number of research methods and doctors’ perceptions of engagement are explored through emerging narrative accounts. Findings from this research study indicate that choice of engagement leads to both the engaged doctor, and the reluctant manager, and has highlighted that choice of engagement is influenced by a perceived internal and external conflict. Outcomes confirm that doctors will choose to engage when they have a personal interest and commitment, feel that they are listened to and have a voice, perceive that they are valued and respected, are involved and able to influence, have power and respect and where the environment that they work in fosters collaboration, facilitates the sharing of expertise and specialised knowledge and offers both personal and professional support leading to improved patient care. Exploring why doctors choose to engage in a clinical network has confirmed the requirement to create a culture for engagement and identified that successful engagement leads to improved patient care, a factor that has been constant throughout this research study.
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Qiang, Qiang. "Network efficiency/performance measurement with vulnerability and robustness analysis with application to critical infrastructure." Amherst, Mass. : University of Massachusetts Amherst, 2009. http://scholarworks.umass.edu/dissertations/AAI3372272/.
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Skjaevesland, Ola. "Optimizing network design in regards of critical streaming media." Thesis, Linnéuniversitetet, Institutionen för datavetenskap, fysik och matematik, DFM, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-17134.
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When designing networks intended to carry real-time media that is critical to arrive several aspects must be considered. For instance, the network must have redundant connectivity, should this traffic (and if so, how) be prioritized in networks where other traffic also travel, which technology is best in the given situation etc. This report will describe technologies that can solve these problems after which some of some of them will be tested in laborations to see how well they measure up in a given problem. The report establishes that in a self-governed LAN link aggregation in collaboration with Virtual Router Redundancy Protocol is a solid solution for providing redundancy with fast reconvergence. On WAN-connections and other shared networks Quality of Service rules should be implemented and in the case of Internet Service Providers a Service Level Agreement should be established.
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Andersson, Karl. "Mapping out dependencies in network components in critical infrastructure." Thesis, Linköpings universitet, Programvara och system, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-143981.
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Companies that operate with critical infrastructure face a growing threat from cyber-attacks while at the same time the development in the business is rapidly moving towards a higher level of digitalization. A common type of system in critical infrastructure is supervisory control and data acquisition systems, these systems have properties that can affect their security and will therefore serve as the basis for this thesis work. To stay protected despite systems changes, companies need to make risk assessments in order to analyze how changes will affect the overall system. One thing that is important to focus on is dependencies within the system, this means that not only interaction among computers and networks are concerned but instead a more holistic view of the system need to be considered. This thesis aims to aid the process of a future risk assessment by providing a methodology to be used as a preparatory step before a risk assessment by describing the current situation of the system. This is done by evaluating two system modeling approaches, and also by proposing a number of perspectives that each provides different kind of information about the system’s dependencies. These perspectives are then evaluated by creating system models and dependency graphs, and discussing the outcomes with experts in a utility company to find out their applicability. According to the experts, the proposed perspectives have promising properties that can be useful in future risk assessments as well as in other scenarios. Moreover, the evaluated modeling approaches got positive comments during evaluation and are considered to serve their purpose.
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Felemban, Emad. "Protocols for Mission-Critical Wireless Sensor Networks." The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1250184419.
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Asif, W. "Critical node identifcation for accessing network vulnerability : a necessary consideration." Thesis, City, University of London, 2016. http://openaccess.city.ac.uk/16398/.
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Timely identification of critical nodes is crucial for assessing network vulnerability and survivability. This thesis presents two new approaches for the identification of critical nodes in a network with the first being an intuition based approach and the second being build on a mathematical framework. The first approach which is referred to as the Combined Banzhaf & Diversity Index (CBDI) uses a newly devised diversity metric, that uses the variability of a node’s attributes relative to its neighbours and the Banzhaf power index which characterizes the degree of participation of a node in forming the shortest path route. The Banzhaf power index is inspired from the theory of voting games in game theory whereas, the diversity index is inspired from the analysis and understanding of the influence of the average path length of a network on its performance. This thesis also presents a new approach for evaluating this average path length metric of a network with reduced computational complexity and proposes a new mechanism for reducing the average path length of a network for relatively larger network structures. The proposed average path length reduction mechanism is tested for a wireless sensor network and the results compared for multiple existing approaches. It has been observed using simulations that, the proposed average path length reduction mechanism outperforms existing approaches by reducing the average path length to a greater extent and with a simpler hardware requirement. The second approach proposed in this thesis for the identification of critical nodes is build on a mathematical framework and it is based on suboptimal solutions of two optimization problems, namely the algebraic connectivity minimization problem and a min-max network utility problem. The former attempts to address the topological as- pect of node criticality whereas, the latter attempts to address its connection-oriented nature. The suboptimal solution of the algebraic connectivity minimization problem is obtained through spectral partitioning considerations. This approach leads to a distributed solution which is computationally less expensive than other approaches that exist in the literature and is near optimal, in the sense that it is shown through simulations to approximate a lower bound which is obtained analytically. Despite the generality of the proposed approaches, this thesis evaluates their performance on a wireless ad hoc network and demonstrates through extensive simulations that the proposed solutions are able to choose more critical nodes relative to other approaches, as it is observed that when these nodes are removed they lead to the highest degrada- tion in network performance in terms of the achieved network throughput, the average network delay, the average network jitter and the number of dropped packets.
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Kling, Joseph A. "Examining Critical Material Supply Chains Through a Bayesian Network Model." Thesis, The George Washington University, 2018. http://pqdtopen.proquest.com/#viewpdf?dispub=10928265.
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The United States economic and national security sectors remain vulnerable to shortages of critical materials due to the risks posed by disruptions in globally-dispersed supply networks. Numerous methods over the past 10 years have been proposed to identify, assess, and evaluate risks in critical material supply chains. This praxis provides a method to quantify the impact of supply disruptions and inform the application of risk mitigation measures for a critical material supply chain from mineral deposits to final platform. It proposes a Bayesian network modeling method not yet applied to the problem in publicly available studies and fits with an assessment methodology proposed by the National Science and Technology Center (NSTC). Results from this study provide indicative answers to how supply disruptions propagate through a selected critical material supply network, which nodes are vulnerable to supply disruptions, and whether mitigating actions can reduce the impact of supply disruptions. The approach here demonstrates that a Bayesian network model can be one of the tools in a criticality assessment methodology.
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Kock, Gustav, and Max Rådelius. "Payair – Reaching for critical mass." Thesis, Uppsala universitet, Företagsekonomiska institutionen, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-233780.
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The mobile payments industry has in recent years experienced large growth and rapid changes. Several different actors are trying to capture the market, to get enough users of their system to reach critical mass. This study investigates how a small Swedish mobile payments company have utilized its business network in their strive to reach critical mass, both in their domestic market and internationally. The study intends to describe how the company has developed its network and which stages of the network development that have been the most important. We utilize the ARA-model to analyze the business network and the Uppsala Model and born global theory to define how the company has internationalized. Our main results indicate that our case company has the mindset of a born global but the particulars of the industry have forced it to internationalize following the Uppsala Model. The development of the business network have to a large part been dependent of the initial activities since this builds the credibility needed to work with large actors. Moreover the business network is found to not only help the company, but to be essential for their plans on reaching critical mass.
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McCausland, Jamieson. "A Proactive Risk-Aware Robotic Sensor Network for Critical Infrastructure Protection." Thèse, Université d'Ottawa / University of Ottawa, 2013. http://hdl.handle.net/10393/30328.
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In this thesis a Proactive Risk-Aware Robotic Sensor Network (RSN) is proposed for the application of Critical Infrastructure Protection (CIP). Each robotic member of the RSN is granted a perception of risk by means of a Risk Management Framework (RMF). A fuzzy-risk model is used to extract distress-based risk features and potential intrusion-based risk features for CIP. Detected high-risk events invoke a fuzzy-auction Multi-Robot Task Allocation (MRTA) algorithm to create a response group for each detected risk. Through Evolutionary Multi-Objective (EMO) optimization, a Pareto set of optimal robot configurations for a response group will be generated using the Non-Dominating Sorting Genetic Algorithm II (NSGA-II). The optimization objectives are to maximize sensor coverage of essential spatial regions and minimize the amount of energy exerted by the response group. A set of non-dominated solutions are produced from EMO optimization for a decision maker to select a single response. The RSN response group will re-organize based on the specifications of the selected response.
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Reynolds, Alexandra. "Crowdsourcing, curating and network power : towards a critical crowdsourced cultural archive." Thesis, Kingston University, 2016. http://eprints.kingston.ac.uk/35849/.
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This thesis explores the use of the crowdsourced digital archive in contemporary museological and cultural projects and investigates ways co-creation can be used more critically and meaningfully by museums, galleries and wider cultural initiatives. A primary focus of the project is the inherent relationship between the archive, curator, power and politics, particularly in relation to the performative mechanisms through which hegemonic power produces, mediates and consolidates cultural norms and ideals. Specifically, this project seeks to explore the complex relationship between the crowdsourced cultural archive and contemporary capitalist power, defined variously as New Capitalism, Network Capitalism or Inclusive Neoliberalism. Referring to a range of contemporary crowdsourced projects, the thesis argues that many existing participatory digital archives performativelt replicate and consolidate hegemonic cultural norms, mirroring historical archival forms in this way. Further, I argue that particular structuration of contemporary capitalism requires that attempts at critically or political action tend to be reassimilated into hegemonic power. Nonetheless, responding to calls for critical digital networks by theorists such as Jodi Dean (2008) and Geert Lovink (2011), the thesis aims to identify new models for the design and structuration of future critical crowdsourced archives. The project looks to Tactical Media, Hacktivism and Critical Digital Art to explore effective online criticality within New Capitalism, while an investigation of alternative architecures for critical collaboraion is undertaken with reference to Free and Open Source Software (FLOSS) and Net Art. Through this research, tenets for future critical crowdsourced cultural projects are delineated, paying particular attention to the role of the curator within the co-created project and critical approaches to digital architecture and design. The thesis primarily employs interpretive research based in Cultural Studies, but also includes findings from nine interviews undertaken with prominent digital project leaders. It is hoped the research will contribute to knowledge within Digital Humanities, Art and Design History, Museum and Gallery Studies, Design Theory and Cultural Studies, as well as contemporary curatorial and archival practice in museums and galleries.
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Zhang, Pengfei, and Neng Fan. "Analysis of budget for interdiction on multicommodity network flows." Springer, 2016. http://hdl.handle.net/10150/623040.
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In this paper, we concentrate on computing several critical budgets for interdiction of the multicommodity network flows, and studying the interdiction effects of the changes on budget. More specifically, we first propose general interdiction models of the multicommodity flow problem, with consideration of both node and arc removals and decrease of their capacities. Then, to perform the vulnerability analysis of networks, we define the function F(R) as the minimum amount of unsatisfied demands in the resulted network after worst-case interdiction with budget R. Specifically, we study the properties of function F(R), and find the critical budget values, such as , the largest value under which all demands can still be satisfied in the resulted network even under the worst-case interdiction, and , the least value under which the worst-case interdiction can make none of the demands be satisfied. We prove that the critical budget for completely destroying the network is not related to arc or node capacities, and supply or demand amounts, but it is related to the network topology, the sets of source and destination nodes, and interdiction costs on each node and arc. We also observe that the critical budget is related to all of these parameters of the network. Additionally, we present formulations to estimate both and . For the effects of budget increasing, we present the conditions under which there would be extra capabilities to interdict more arcs or nodes with increased budget, and also under which the increased budget has no effects for the interdictor. To verify these results and conclusions, numerical experiments on 12 networks with different numbers of commodities are performed.
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Murić, Goran. "Resilience of the Critical Communication Networks Against Spreading Failures." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-228883.
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A backbone network is the central part of the communication network, which provides connectivity within the various systems across large distances. Disruptions in a backbone network would cause severe consequences which could manifest in the service outage on a large scale. Depending on the size and the importance of the network, its failure could leave a substantial impact on the area it is associated with. The failures of the network services could lead to a significant disturbance of human activities. Therefore, making backbone communication networks more resilient directly affects the resilience of the area. Contemporary urban and regional development overwhelmingly converges with the communication infrastructure expansion and their obvious mutual interconnections become more reciprocal.
Spreading failures are of particular interest. They usually originate in a single network segment and then spread to the rest of network often causing a global collapse. Two types of spreading failures are given focus, namely: epidemics and cascading failures. How to make backbone networks more resilient against spreading failures? How to tune the topology or additionally protect nodes or links in order to mitigate an effect of the potential failure? Those are the main questions addressed in this thesis.
First, the epidemic phenomena are discussed. The subjects of epidemic modeling and identification of the most influential spreaders are addressed using a proposed Linear Time-Invariant (LTI) system approach. Throughout the years, LTI system theory has been used mostly to describe electrical circuits and networks. LTI is suitable to characterize the behavior of the system consisting of numerous interconnected components. The results presented in this thesis show that the same mathematical toolbox could be used for the complex network analysis.
Then, cascading failures are discussed. Like any system which can be modeled using an interdependence graph with limited capacity of either nodes or edges, backbone networks are prone to cascades. Numerical simulations are used to model such failures. The resilience of European National Research and Education Networks (NREN) is assessed, weak points and critical areas of the network are identified and the suggestions for its modification are proposed.
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de, Wasseige Mathieu. "A critical analysis of ideological narratives in contemporary US network television series." Doctoral thesis, Universite Libre de Bruxelles, 2011. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209843.
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This critical study unveils the ideological underpinning of contemporary network series narratives through a thematic approach combined with the analysis of the strategies of representation that support the ideological inclination of the series/Cette analyse critique dévoile l'idéologie sous-jacente des séries télévisées contemporaines des networks américains par une approche thématique combinée à une analyse des stratégies de représentations qui appuient la tendance idéologique de ces sériesDoctorat en Langues et lettres
info:eu-repo/semantics/nonPublished
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Vinall, Sarah A. J. "A critical look at nutritional value of commercials on the Nickelodeon Network." Scholarly Commons, 2008. https://scholarlycommons.pacific.edu/uop_etds/689.
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Food advertising aimed at children in America has been proven to directly impact food preferences, eating behavior and brand loyalty of youth (Story & French, 2004). The purpose of this study was to evaluate the content of television commercials that occurred during children's programming on the popular children's network Nickelodeon. This study examined the frequency, nutritional content and overall advertising techniques associated with food, beverage and restaurant commercials. It also assessed the degree to which children are being exposed to the promotion of unhealthy food, beverage restaurant commercials.
This study examined commercials that aired on the Nickelodeon Network between Monday, August 11 through Friday, August 15, 2008 between 3 p.m. and 5 p.m. on the Comcast Cable System in Stockton, California. The programming was recorded on a VHS tape and then later reviewed and analyzed. Each commercial was examined in the following areas: nutritional content; slogan; branded characters; premium; link to a movie and healthy message.
This study demonstrated that 40.65% of the commercials airing between 3 p.m. and 5 p.m. on the Nickelodeon television network are for food, beverage and/or restaurants. Twenty-six percent of food, beverage and restaurant commercials met or exceeded the daily recommended levels of fat, added sugars, and sodium, and fell short of providing essential nutrients as outlined by the United States Department of Agriculture (USDA) (United States Department of Agriculture, 2008).
The results of this study indicate that a considerable amount of food commercials targeting children as consumers. Government regulation seems unlikely due to the First Amendment, rights to free speech. This study points to several suggestions for advertisers, advocates, Children's Advertising Review Unit (CARU) teachers and parents to address the issue of advertising to children. Some of the suggestions include stricter self-regulation, education and parental responsibility.
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Öberg, Oskar. "Critical Branching Regulation of the E-I Net Spiking Neural Network Model." Thesis, Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-76770.
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Spiking neural networks (SNN) are dynamic models of biological neurons, that communicates with event-based signals called spikes. SNN that reproduce observed properties of biological senses like vision are developed to better understand how such systems function, and to learn how more efficient sensor systems can be engineered. A branching parameter describes the average probability for spikes to propagate between two different neuron populations. The adaptation of branching parameters towards critical values is known to be important for maximizing the sensitivity and dynamic range of SNN. In this thesis, a recently proposed SNN model for visual feature learning and pattern recognition known as the E-I Net model is studied and extended with a critical branching mechanism. The resulting modified E-I Net model is studied with numerical experiments and two different types of sensory queues. The experiments show that the modified E-I Net model demonstrates critical branching and power-law scaling behavior, as expected from SNN near criticality, but the power-laws are broken and the stimuli reconstruction error is higher compared to the error of the original E-I Net model. Thus, on the basis of these experiments, it is not clear how to properly extend the E-I Net model properly with a critical branching mechanism. The E-I Net model has a particular structure where the inhibitory neurons (I) are tuned to decorrelate the excitatory neurons (E) so that the visual features learned matches the angular and frequency distributions of feature detectors in visual cortex V1 and different stimuli are represented by sparse subsets of the neurons. The broken power-laws correspond to different scaling behavior at low and high spike rates, which may be related to the efficacy of inhibition in the model.
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Felczak, Michael. "(Re)Designing the Internet: a critical constructivist analysis of the next generation Internet Protocol /." Burnaby B.C. : Simon Fraser University, 2005. http://ir.lib.sfu.ca/handle/1892/2132.
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Xiang, Qiao. "In-network processing for mission-critical wireless networked sensing and control| A real-time, efficiency, and resiliency perspective." Thesis, Wayne State University, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=3619123.
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As wireless cyber-physical systems (WCPS) are increasingly being deployed in mission-critical applications, it becomes imperative that we consider application QoS requirements in in-network processing (INP). In this dissertation, we explore the potentials of two INP methods, packet packing and network coding, on improving network performance while satisfying application QoS requirements. We find that not only can these two techniques increase the energy efficiency, reliability, and throughput of WCPS while satisfying QoS requirements of applications in a relatively static environment, but also they can provide low cost proactive protection against transient node failures in a more dynamic wireless environment.
We first study the problem of jointly optimizing packet packing and the timeliness of data delivery. We identify the conditions under which the problem is strong NP-hard, and we find that the problem complexity heavily depends on aggregation constraints instead of network and traffic properties. For cases when the problem is NP-hard, we show that there is no polynomial-time approximation scheme (PTAS); for cases when the problem can be solved in polynomial time, we design polynomial time, offline algorithms for finding the optimal packet packing schemes. We design a distributed, online protocol tPack that schedules packet transmissions to maximize the local utility of packet packing at each node. We evaluate the properties of tPack in NetEye testbed. We find that jointly optimizing data delivery timeliness and packet packing and considering real-world aggregation constraints significantly improve network performance.
We then work on the problem of minimizing the transmission cost of network coding based routing in sensor networks. We propose the first mathematical framework so far as we know on how to theoretically compute the expected transmission cost of NC-based routing in terms of expected number of transmission. Based on this framework, we design a polynomial-time greedy algorithm for forwarder set selection and prove its optimality on transmission cost minimization. We designed EENCR, an energy-efficient NC-based routing protocol that implement our forwarder set selection algorithm to minimize the overall transmission cost. Through comparative study on EENCR and other state-of-the-art routing protocols, we show that EENCR significantly outperforms CTP, MORE and CodeOR in delivery reliability, delivery cost and network goodput.
Furthermore, we study the 1+1 proactive protection problem using network coding. We show that even under a simplified setting, finding two node-disjoint routing braids with minimal total cost is NP-hard. We then design a heuristic algorithm to construct two node-disjoint braids with a transmission cost upper bounded by two shortest node-disjoint paths. And we design ProNCP, a proactive NC-based protection protocol using similar design philosophy as in EENCR. We evaluate the performance of ProNCP under various transient network failure scenarios. Experiment results show that ProNCP is resilient to various network failure scenarios and provides a state performance in terms of reliability, delivery cost and goodput.
Our findings in this dissertation explore the challenges, benefits and solutions in designing real-time, efficient, resilient and QoS-guaranteed wireless cyber-physical systems, and our solutions shed lights for future research on related topics.
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Cotilla-Sanchez, J. Eduardo. "A Complex Network Approach to Analyzing the Structure and Dynamics of Power Grids." ScholarWorks @ UVM, 2010. http://scholarworks.uvm.edu/graddis/57.
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Electrical energy generation and distribution systems are good examples of complex systems. They include continuous, discrete, and social dynamics. They are operated by millions of human and non-human (or electro-mechanical) agents, and they show statistical properties found in other complex systems, such as power-law distributions in failure sizes. A number of recent large blackouts in Europe and North America have emphasized the societal importance of understanding these dynamics. Classical electromagnetic analysis alone frequently does not provide the insight required to characterize and mitigate risks in the electricity infrastructure. The objective of this thesis is to obtain insights into the dynamics of power grids using tools from the science of complex systems. In particular, this thesis will compare the topology, electrical structure, and attack/failure tolerance of power grids with those of theoretical graph structures such as regular, random, small-world, and scale-free networks. Simulation results in this thesis will describe the cost of the disturbances as a function of failure or attack sizes. The cost associated with network perturbations is often measured by changes on the diameter or average path length, whereas in the electricity industry, the loss of power demand (or blackout size) is the best indicator of the cost or impact of disturbances to electricity infrastructure.
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Schaberreiter, T. (Thomas). "A Bayesian network based on-line risk prediction framework for interdependent critical infrastructures." Doctoral thesis, Oulun yliopisto, 2013. http://urn.fi/urn:isbn:9789526202129.
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Abstract Critical Infrastructures (CIs) are an integral part of our society and economy. Services like electricity supply or telecommunication services are expected to be available at all times and a service failure may have catastrophic consequences for society or economy. Current CI protection strategies are from a time when CIs or CI sectors could be operated more or less self-sufficient and interconnections among CIs or CI sectors, which may lead to cascading service failures to other CIs or CI sectors, where not as omnipresent as today. In this PhD thesis, a cross-sector CI model for on-line risk monitoring of CI services, called CI security model, is presented. The model allows to monitor a CI service risk and to notify services that depend on it of possible risks in order to reduce and mitigate possible cascading failures. The model estimates CI service risk by observing the CI service state as measured by base measurements (e.g. sensor or software states) within the CI service components and by observing the experienced service risk of CI services it depends on (CI service dependencies). CI service risk is estimated in a probabilistic way using a Bayesian network based approach. Furthermore, the model allows CI service risk prediction in the short-term, mid-term and long-term future, given a current CI service risk and it allows to model interdependencies (a CI service risk that loops back to the originating service via dependencies), a special case that is difficult to model using Bayesian networks. The representation of a CI as a CI security model requires analysis. In this PhD thesis, a CI analysis method based on the PROTOS-MATINE dependency analysis methodology is presented in order to analyse CIs and represent them as CI services, CI service dependencies and base measurements. Additional research presented in this PhD thesis is related to a study of assurance indicators able to perform an on-line evaluation of the correctness of risk estimates within a CI service, as well as for risk estimates received from dependencies. A tool that supports all steps of establishing a CI security model was implemented during this PhD research. The research on the CI security model and the assurance indicators was validated based on a case study and the initial results suggest its applicability to CI environmentsTiivistelmä Tässä väitöskirjassa esitellään läpileikkausmalli kriittisten infrastruktuurien jatkuvaan käytön riskimallinnukseen. Tämän mallin avulla voidaan tiedottaa toisistaan riippuvaisia palveluita mahdollisista vaaroista, ja siten pysäyttää tai hidastaa toisiinsa vaikuttavat ja kumuloituvat vikaantumiset. Malli analysoi kriittisen infrastruktuurin palveluriskiä tutkimalla kriittisen infrastruktuuripalvelun tilan, joka on mitattu perusmittauksella (esimerkiksi anturi- tai ohjelmistotiloina) kriittisen infrastruktuurin palvelukomponenttien välillä ja tarkkailemalla koetun kriittisen infrastruktuurin palveluriskiä, joista palvelut riippuvat (kriittisen infrastruktuurin palveluriippuvuudet). Kriittisen infrastruktuurin palveluriski arvioidaan todennäköisyyden avulla käyttämällä Bayes-verkkoja. Lisäksi malli mahdollistaa tulevien riskien ennustamisen lyhyellä, keskipitkällä ja pitkällä aikavälillä, ja mahdollistaa niiden keskinäisten riippuvuuksien mallintamisen, joka on yleensä vaikea esittää Bayes-verkoissa. Kriittisen infrastruktuurin esittäminen kriittisen infrastruktuurin tietoturvamallina edellyttää analyysiä. Tässä väitöskirjassa esitellään kriittisen infrastruktuurin analyysimenetelmä, joka perustuu PROTOS-MATINE -riippuvuusanalyysimetodologiaan. Kriittiset infrastruktuurit esitetään kriittisen infrastruktuurin palveluina, palvelujen keskinäisinä riippuvuuksina ja perusmittauksina. Lisäksi tutkitaan varmuusindikaattoreita, joilla voidaan tutkia suoraan toiminnassa olevan kriittisen infrastruktuuripalvelun riskianalyysin oikeellisuutta, kuin myös riskiarvioita riippuvuuksista. Tutkimuksessa laadittiin työkalu, joka tukee kriittisen infrastruktuurin tietoturvamallin toteuttamisen kaikkia vaiheita. Kriittisen infrastruktuurin tietoturvamalli ja varmuusindikaattorien oikeellisuus vahvistettiin konseptitutkimuksella, ja alustavat tulokset osoittavat menetelmän toimivuuden
Kurzfassung In dieser Doktorarbeit wird ein Sektorübergreifendes Modell für die kontinuierliche Risikoabschätzung von kritische Infrastrukturen im laufenden Betrieb vorgestellt. Das Modell erlaubt es, Dienstleistungen, die in Abhängigkeit einer anderen Dienstleistung stehen, über mögliche Gefahren zu informieren und damit die Gefahr des Übergriffs von Risiken in andere Teile zu stoppen oder zu minimieren. Mit dem Modell können Gefahren in einer Dienstleistung anhand der Überwachung von kontinuierlichen Messungen (zum Beispiel Sensoren oder Softwarestatus) sowie der Überwachung von Gefahren in Dienstleistungen, die eine Abhängigkeit darstellen, analysiert werden. Die Abschätzung von Gefahren erfolgt probabilistisch mittels eines Bayessches Netzwerks. Zusätzlich erlaubt dieses Modell die Voraussage von zukünftigen Risiken in der kurzfristigen, mittelfristigen und langfristigen Zukunft und es erlaubt die Modellierung von gegenseitigen Abhängigkeiten, die im Allgemeinen schwer mit Bayesschen Netzwerken darzustellen sind. Um eine kritische Infrastruktur als ein solches Modell darzustellen, muss eine Analyse der kritischen Infrastruktur durchgeführt werden. In dieser Doktorarbeit wird diese Analyse durch die PROTOS-MATINE Methode zur Analyse von Abhängigkeiten unterstützt. Zusätzlich zu dem vorgestellten Modell wird in dieser Doktorarbeit eine Studie über Indikatoren, die das Vertrauen in die Genauigkeit einer Risikoabschätzung evaluieren können, vorgestellt. Die Studie beschäftigt sich sowohl mit der Evaluierung von Risikoabschätzungen innerhalb von Dienstleistungen als auch mit der Evaluierung von Risikoabschätzungen, die von Dienstleistungen erhalten wurden, die eine Abhängigkeiten darstellen. Eine Software, die alle Aspekte der Erstellung des vorgestellten Modells unterstützt, wurde entwickelt. Sowohl das präsentierte Modell zur Abschätzung von Risiken in kritischen Infrastrukturen als auch die Indikatoren zur Uberprüfung der Risikoabschätzungen wurden anhand einer Machbarkeitsstudie validiert. Erste Ergebnisse suggerieren die Anwendbarkeit dieser Konzepte auf kritische Infrastrukturen
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Appel, Matt Andrew. "Security Control Mechanism for Safety Critical Functions Operating on Automotive Controller Area Network." The Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1587645195243586.
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SACCO, ALESSIO. "Towards Autonomous Computer Networks in Support of Critical Systems." Doctoral thesis, Politecnico di Torino, 2022. http://hdl.handle.net/11583/2968454.
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Axelsson, Emma. "The Mature Micro Business and its Network : Advancing the qualitative case study on network tie content and strength." Thesis, Umeå universitet, Företagsekonomi, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-74936.
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The value creating mechanism of business networks has been acknowledged in research (Casson & Della Giusta, 2007, p. 221; Granovetter, 1973; Jones, Hesterly & Borgatti, 1997, p. 912). Within small business research, focus has been on network structure (Jack, Moult, Anderson & Dodd. 2010, p. 317; Shaw, 2006, p. 5; Curran et al., 1993, p. 13), disregarding dynamic factors such as network content, strength and processes. Network studies within start-up businesses have received attention (Witt, 2004, p 392); hence limited research exists concerning more well-established small businesses’ networks. These research gaps will here be addressed from the perspective of a smaller business, a micro business, at a stage of firm maturity. Small business research suffers from methodological fragmentation and underdevelopments, favoring positivistic and quantitative methods (Blackburn & Kovalainen, 2009, p. 128-129). To address this, this research seeks to explore qualitative alternatives, which can be increasingly fruitful for the small business field when studying networks (Jack et al., 2010, p. 317). Recognizing the social and contextual embeddedness of the micro business and its sensitivity to external changes (Curran & Blackburn, 2001, p. 7), this research opts for a qualitative in-depth case study to explore these contextual mechanisms. This research adopts a critical realist stance using ethnographic and process research methods of grounded theory, taking the sequence of events into account in the analysis. This present research combines strands of research of core disciplines (sociology) to newer disciplines (entrepreneurship) to produce a conceptual mapping. This deductive conceptual mapping is used as basis for the data collection and as a tool for analysis in this by nature inductive study. This study finds that network tie content and strength deepen the understanding of networks and their maintenance, beyond the static mapping of structure. Network tie content and strength does influence structure and is in turn influenced by context. This provides answer to why the network appears as it does. The appearance of the mature micro business’ network indicates that growth ambitions can be inhibited by contextual factors such as limited access to new opportunities. This present study finds and agrees with Van Maanen (2011a, p. 226-227) that the single case study and ethnographic observant-participant methods, often criticized for not producing substantial findings, are informative as they allow exploring the influence of contextual factors. The intended audience of research academics and local/regional/national entrepreneurship policy makers should recognize that research which enhances tools for apprehending contextual factors can provide interesting results. The research design disregards generalization capabilities in favor of accounting for the research process of the researcher and its subject. This is argued to give a fruitful version of truth of network appearance in terms of content and strength and why it appears as such.
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Xu, Xinfeng. "Modeling and Predicting Incidence: Critical Systems Failures and Flu Infection Cases." Thesis, Virginia Tech, 2019. http://hdl.handle.net/10919/89909.
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Given several related critical infrastructure (CI) networks, such as power grid, transportation, and water systems, one crucial question emerges: how to model the propagation of failed facilities and predict their spread over time to the whole system? Given digital surveillance data, can we predict the impact of Influenza-Like Illness (ILI), including the percentage of outpatient doctors visits, the season duration, and peak? These two questions are related to modeling and predicting the incidence of different types of contagions. In the case of CI, the contagions are the failures of facilities. In the case of flu spread, the contagions are the infective ILI.
In this thesis, in the case of CI, we give a novel model of failure cascades and use it to identify key facilities in an optimization-based approach, called HotSpots. In the case of flu spread, we develop a deep neural network, EpiDeep, to predict multiple key epidemiology metrics. In both of these applications, we use the dynamics of propagation to develop better approaches. By collaborating with Oak Ridge National Laboratory (ORNL) and working on the real CI networks provided by them, we find that HotSpots helps solve what-if scenarios. By using the digital surveillance data reported by the Centers for Disease Control and Prevention (CDC), we carry on experiments and find that EpiDeep is better than non-trivial baselines and outperforms them by up to 40%. We believe the generality of our approaches, and it can be applied to other propagation-based scenarios in infrastructure and epidemiology.M.S.
Critical Infrastructure Systems (CIS), including the power grid, transportation, and gas systems, are essential to national security, economy, and political stability. Moreover, they are interconnected and are vulnerable to potential failures. The previous event, like 2012 Hurricane Sandy, showed how these interdependencies can lead to catastrophic disasters among the whole systems. Therefore, one crucial question emerges: Given several related CIS networks: how to model the propagation of failed facilities and predict their spread over time to the whole system? Similarly, in the case of seasonal influenza, it always remains a significant health issue for many people in every country. The time-series of the weighted Influenza-like Illness (wILI) data are provided to researchers by the US Center for Disease Control and Prevention (CDC), and researchers use them to predict several key epidemiological metrics. The question, in this case, is: Given the wILI time-series, can we predict the impact of Influenza-Like Illness (ILI) accurately and efficiently? Both of these questions are related to modeling and predicting the incidence of different types of contagions. Contagions are any infective trend which can spread inside a network, including failures of facilities, illness of human, and popular news. In the case of CIS, the contagions are the failures of facilities. In the case of flu spread, the contagions are the infective ILI. In this thesis, in the case of CI, we present a novel model of failure cascades and use it to identify critical facilities in an optimization-based approach. In the case of flu spread, we develop a deep neural network to predict multiple key epidemiology metrics. In both of these applications, we use the dynamics of propagation to create better approaches. By collaborating with ORNL and working on the real CI networks provided by them, we find that F-CAS captures the dynamics of the interconnected CI networks. In the experiments using the wILI data from CDC, we find that EpiDeep is better than non-trivial baselines and outperforms them by up to 40%. We believe the generality of our approaches, and it can be applied to other propagation-based scenarios in infrastructure and epidemiology.
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Hinds, David. "Social Network Structure as a Critical Success Condition for Open Source Software Project Communities." FIU Digital Commons, 2008. http://digitalcommons.fiu.edu/etd/27.
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In recent years, a surprising new phenomenon has emerged in which globally-distributed online communities collaborate to create useful and sophisticated computer software. These open source software groups are comprised of generally unaffiliated individuals and organizations who work in a seemingly chaotic fashion and who participate on a voluntary basis without direct financial incentive. The purpose of this research is to investigate the relationship between the social network structure of these intriguing groups and their level of output and activity, where social network structure is defined as 1) closure or connectedness within the group, 2) bridging ties which extend outside of the group, and 3) leader centrality within the group. Based on well-tested theories of social capital and centrality in teams, propositions were formulated which suggest that social network structures associated with successful open source software project communities will exhibit high levels of bridging and moderate levels of closure and leader centrality. The research setting was the SourceForge hosting organization and a study population of 143 project communities was identified. Independent variables included measures of closure and leader centrality defined over conversational ties, along with measures of bridging defined over membership ties. Dependent variables included source code commits and software releases for community output, and software downloads and project site page views for community activity. A cross-sectional study design was used and archival data were extracted and aggregated for the two-year period following the first release of project software. The resulting compiled variables were analyzed using multiple linear and quadratic regressions, controlling for group size and conversational volume. Contrary to theory-based expectations, the surprising results showed that successful project groups exhibited low levels of closure and that the levels of bridging and leader centrality were not important factors of success. These findings suggest that the creation and use of open source software may represent a fundamentally new socio-technical development process which disrupts the team paradigm and which triggers the need for building new theories of collaborative development. These new theories could point towards the broader application of open source methods for the creation of knowledge-based products other than software.
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Wei, Zheng S. M. Massachusetts Institute of Technology. "Critical enhancements of a dynamic traffic assignment model for highly congested, complex urban network." Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/58283.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2010.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 109-115).
To accurately replicate the highly congested traffic situation of a complex urban network, significant challenges are posed to current simulation-based dynamic traffic assignment (DTA) models. This thesis discusses these challenges and corresponding solutions with consideration of model accuracy and computational efficiency. DynaMITP, an off-line mesoscopic DTA model is enhanced. Model success is achieved by several critical enhancements aimed to better capture the traffic characteristics in urban networks. A Path-Size Logit route choice model is implemented to address the overlapping routes problem. The explicit representation of lane-groups accounts for traffic delays and queues at intersections. A modified treatment of acceptance capacity is required to deal with the large number of short links in the urban network. The network coding is revised to maintain enough loader access capacity in order to avoid artificial bottlenecks. In addition, the impacts of bicycles and pedestrians on automobile traffic is modeled by calibrating dynamic road segment capacities. The enhanced model is calibrated and applied to a case study network extracted from the city of Beijing, China. Data used in the calibration include sensor counts and floating car travel time. The improvements of the model performance are indicated by promising results from validation tests.
by Zheng Wei.
S.M.
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Kejuo, Kingsley. "TOPIC: Critical Success Factors: Telecommunication Network equipment Procurement projects. A case study of MTN Nigeria." Thesis, KTH, Tillämpad maskinteknik (KTH Södertälje), 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-118753.
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De, Vos Marieta. "Critical factors in NACOSA’s success as a network organisation in the HIV and AIDS sector." Thesis, Stellenbosch : Stellenbosch University, 2015. http://hdl.handle.net/10019.1/96802.
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Thesis (MPhil)--Stellenbosch University, 2015.ENGLISH ABSTRACT: NACOSA had an eventful history spanning 22 years. The first phase between 1992 and 2001 is labeled Great Expectations as the composite multi-sectoral structure started a groundbreaking initiative on HIV and AIDS in South Africa and believed that the first AIDS plan drafted by them would be implemented as planned. Expectations came to nothing as government struggled to find its feet through a decade of blunders leading to the demise of the structure by end 2001. The next phase between 2001 and 2010 is labeled Starting Over as the Western Cape branch of NACOSA reinvented itself as a community mobilisation network for the province. Within a period of ten years Western Cape NACOSA developed into a successful national network with a large membership fully involved through its networking, capacity building and promoting dialogue functions. The third phase between 2010 and 2015 is labeled Rapid Growth as NACOSA developed into a large training and grant management agency with strong systems providing funding to its members through sub-granting. Networking continued at a slower pace but is still highly important for the organisation. The network contributes to localised social capital through shared learning and collaboration. NACOSA‟s sustainability has been developed through the ability to raise long-term funds for network activities, capacity building of members and coordinated service delivery on the ground. NACOSA also has a culture of identifying and acting fast on opportunities and adapting to change when it is needed. Strategic factors attributing to the success of NACOSA are a sector based approach promoting diversity in its membership; a consistently focused and shared purpose throughout the years; a community agent approach believing in and advocating for community systems strengthening; obtaining a mandate from network members for main strategy changes; strategic partnerships; a strong capacity building approach focussing on organisational and programmatic competencies; not competing with network members but acting as main weaver; creating specialist networks for specific HIV-related causes; a committed representative executive committee and skilled staff; bringing groups together on a regular basis for discussions and strategising; a variety of social media; and a network mindset intent on a culture of learning and building trust between member organisations.
AFRIKAANSE OPSOMMING: NACOSA het 'n gebeurtenisvolle geskiedenis wat strek oor 'n periode van 22 jaar. Die eerste fase tussen 1992 en 2001 word genoem Groot Verwagtinge, verwysende na die saamgevoegde multi-sektorale struktuur wat ontstaan het as die eerste groot MIV en VIGS inisiatief in Suid-Afrika. Hulle het verwag dat hul eerste VIGS-plan geïmplementeer sou word soos wat hulle dit beplan het. Hul verwagtinge het egter skipbreuk gely as gevolg van die regering wat oor die dekade heen hul voete gesleep en foute gemaak het wat uiteindelik gelei het tot die struktuur se ondergang in 2001. Die volgende fase tussen 2001 en 2010 word genoem Oorbegin verwysende na die Wes-Kaap tak van NACOSA wat hulself herskep het as „n gemeenskapsmobiliseringsnetwerk. Wes-Kaap NACOSA het binne tien jaar weer ontwikkel in 'n suksesvolle nasionale netwerk met 'n groot ledetal wat volledig ingeskakel is by die organisasie se netwerk, kapasiteitsbou en bevordering van dialoogaktiwiteite. Die derde fase tussen 2010 en 2015 word genoem Snelle Groei verwysende na NACOSA se ontwikkeling in 'n groot opleidings- en fondsbestuursagentskap met sterk stelsels wat befondsing aan hul lede verskaf. Netwerkskakeling het voortgeduur teen 'n stadiger pas maar is steeds baie belangrik vir die organisasie. Die netwerk dra by tot die bou van plaaslike sosiale kapitaal deur middel van samewerking en saam leer. NACOSA se volhoubaarheid het ontwikkel deur hul vaardigheid om langtermynfondse in te samel vir netwerkaktiwiteite, kapasiteitsbou en gekoördineerde dienslewering op grondvlak. NACOSA het ook 'n kultuur om geleenthede vinnig te identifiseer en daarop te reageer, asook om aan te pas by veranderinge wanneer nodig. Strategiese faktore wat bygedra het tot NACOSA se sukses sluit in 'n wye sektorbenadering met diverse lidmaatskap; 'n konsekwente gedeelde doelwit oor die jare; die bevordering van sterk gemeenskapstelsels; die verkryging van 'n mandaat by netwerklede vir strategie-veranderinge; strategiese vennootskappe; 'n sterk kapasiteitsboubenadering wat fokus op organisatoriese en programmatiese vaardighede; geen kompetisie met lede-organisasies maar eerder die rol van “hoofwewer”; skep van spesialisnetwerke vir spesifieke MIV-verwante kwessies; 'n toegewyde raad en vaardige personeel; gereelde bymekaarbring van groepe vir dialoog en strategie bou; 'n verskeidenheid van sosiale media; en 'n netwerk denkpatroon gefokus op 'n leerkultuur en die bou van vertroue tussen lede.
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Teo, Peng (Troy). "Autonomous lung tumor and critical structure tracking using optical flow computation and neural network prediction." IOP Publishing Ltd, 2012. http://hdl.handle.net/1993/31874.
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Objectives. The goal in radiotherapy is to deliver adequate radiation to the tumor volume while limiting damage to the surrounding healthy tissue. However, this goal is challenged by respiratory-induced motion. The objective of this work was to identify whether motion in electronic portal images can be tracked with an optical flow algorithm and whether a neural network can predict tumor motion.
Methods. A multi-resolution optical flow algorithm that incorporates weighting based on the differences between image frames was used to automatically sample the vectors corresponding to the motion. The global motion was obtained by computing the average weighted mean from the set of vectors. The algorithm was evaluated using tumor trajectories taken from seven lung cancer patients, a 3D printed patient tumor and a virtual dynamic multi-leaf collimator (DMLC) system. The feasibility of detecting and tracking motion at the field edge was examined with a proof-of-concept implementation that included (1) an algorithm that detected local motion, and (2) a control algorithm that adapted the virtual MLC. To compensate for system latency, a generalized neural network, using both offline (treatment planning data) and online (during treatment delivery) learning, was implemented for tumor motion prediction.
Results and Conclusions. The algorithm tracked the global motion of the target with an accuracy of around 0.5 mm. While the accuracy is similar to other methods, this approach does not require manual delineation of the target and can, therefore, provide real-time autonomous motion estimation during treatment. Motion at the treatment field edge was tracked with an accuracy of -0.4 ± 0.3 mm. This proof-of-concept simulation demonstrated that it is possible to adapt MLC leaves based on the motion detected at the field edges. Unplanned intrusions of external organs-at-risk could be shielded. A generalized network with a prediction error of 0.59 mm, and a shorter initial learning period (compared to previous studies) was achieved. This network may be used as a plug-and-play predictor in which tumor position could be predicted at the start of treatment and the need for pretreatment data and optimization for individual patients may be avoided.February 2017
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BANERJEE, SUMON. "Spatial and Temporal Correlation and Extracting Critical Attribute in a Three dimensional Wireless Sensor Network." University of Cincinnati / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1214590299.
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Elkin-Frankston, Seth. "Anatomical and functional impact of critical brain areas to network activity and basic visual function." Thesis, Boston University, 2013. https://hdl.handle.net/2144/12752.
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Thesis (Ph.D.)--Boston University
PLEASE NOTE: Boston University Libraries did not receive an Authorization To Manage form for this thesis or dissertation. It is therefore not openly accessible, though it may be available by request. If you are the author or principal advisor of this work and would like to request open access for it, please contact us at open-help@bu.edu. Thank you.A set of widely distributed brain areas, collectively known as the fronto-parietal network, serve to modulate aspects of visual perception. However, the unique influence exerted by these regions on low-level visual processing remains unclear. The goals of this thesis were (1) to examine how right frontal, parietal and occipital brain areas interact to process and modulate visual function and (2) to investigate the ability to improve foveal visual performance by means of noninvasive neurostimulation. In a first set of experiments, visual percepts known as 'phosphenes' were measured following low-frequency neurostimulation of the right occipital pole, Intraparietal Sulcus (IPS) or Frontal Eye Fields (FEF). Stimulation of the occipital pole and IPS were capable of evoking phosphenes with similar appearances. Furthermore, occipital or IPS stimulation decreased the excitability of the locally stimulated region but had no effect on the non-stimulated brain area. These results indicate a lack of sufficient inter-regional interactions capable of supporting long-range changes in brain activity. In a second set of experiments, contrast sensitivity and reaction times were assessed as the capacity to detect centrally located, high or low spatial frequency stimuli. Low-frequency rTMS to the FEF, but not the occipital pole or IPS improved contrast sensitivity for high spatial frequency stimuli. Stimulation of the occipital pole decreased reaction times for low spatial frequency stimuli and was shown to depend on transcollicular projections. Finally, stimulation of the IPS decreased reaction times for both types of stimuli. These effects however did not appear to depend on transcollicular pathways, indicating that performance was enhanced through cortico-cortical connections. In a final set of experiments, we investigated whether patterns of individual white matter connectivity linking stimulated brain regions could predict the effects of neurostimulation on visual processing and performance. None of the probability measures however correlated with changes in visual performance. Overall, these data suggest that occipital, parietal, frontal and tectal areas uniquely contribute to the modulation of visual perception. Moreover, results show that targeted stimulation to these brain regions serves to generate lasting improvements in visual performance, which could be used to enhance aspects of vision in healthy and clinical populations.
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Lee, Debra A. "The Role of Relationships During Chronic Critical Illness." Case Western Reserve University School of Graduate Studies / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=case1307657748.
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KASSEM, ALEXANDER, and HAKIM LIAM JAFAR. "Assessing critical success factors (CSFs) for a supplier in a relationship-driven B2B-market." Thesis, KTH, Industriell Management, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-199221.
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It is necessary for firms to consider and understand sales and buying processes to improve relationship initiation and accommodate the buyers and end-customers. Relationships within the supply chain enable firms to access beneficial abilities to overcome challenges and complexities of new products, shrinking time to market, capital intensities and thus meeting competitive challenges. Developing strategic partnerships with key supply chain actors is an emerging trend in supply chain management. Firms are seen as complex nodes in interdependent supply chain networks where competitive advantages are met by collaboration and co-creation in the business environment. The aim of this study is to investigate the problem areas and assess the critical success factors for a supplier within a relation driven B2B three-tier supply chain network by adopting an abductive, theory-building methodology using qualitative case studies, using the case company as a focal firm. Two different three-tier supply chains are investigated within the focal company with an endcustomer, a buyer and a supplier in each supply chain structure. The study offered us four dominant themes common to all findings. These are structural power within the supply chain network, relationship stability with the end-customer, market knowledge and structural network position. In our discussion, we looked for common denominators to frame our propositions. We organized the propositions in each of the four key themes that emerged from the findings. We then incorporated literature at this stage to compare and contrast our findings, essentially using the literature study as an additional source of validation. The main theoretical contributions of this research involve targeting a new area of importance in the crossroads of supply chain management, customer relationship management and knowledge management, and identifying four critical success factors in a market entry on a relationship-driven industrial B2B market.
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Zaki, Hindi Ayat. "Transport of critical services over unlicensed spectrum in 5G networks." Electronic Thesis or Diss., Institut polytechnique de Paris, 2020. http://www.theses.fr/2020IPPAS022.
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Cette thèse étudie le transport de services critiques dans les réseaux 5G, où le spectre non-licencié est préconisé pour minimiser le coût et faire face à la forte demande de ressources en fréquences. Nous évaluons d'abord les performances des services critiques type URLLC (Ultra-Reliable Low-Latency Communication) qui a des exigences strictes en matière de fiabilité et de latence, de l'ordre de 99,999% et 1 ms, respectivement, transporté dans le spectre non-licencié. Nous proposons un modèle basé sur une chaîne de Markov pour quantifier la fiabilité sous contrainte de délai, sous procédure d'accès au support Listen-Before-Talk (LBT), puis nous en déduisons le nombre maximum de stations pouvant être servies en même temps, tout en respectant l'URLLC contraintes. Cette analyse est ensuite utilisée pour étudier de nouvelles méthodes pour la transmission conjointe d'URLLC sur les spectres non-licencié et licencié. Nous proposons trois méthodes pour l'accès conjoint aux ressources disponibles et démontrons que la méthode optimale pour accéder aux ressources consiste à utiliser des ressources licenciées, uniquement lorsque la transmission dans le système non-licencié échoue dans un budget de temps donné. Cette méthode est ensuite étudiée dans le cas de plusieurs tenants à proximité en concurrence sur le même canal non-licencié. Si tous les tenants essaient de maximiser leur utilisation des ressources non-licenciées, tout le monde se retrouvera dans une situation type « tragédie des biens communs ». Nous montrons qu'au moins un point d'équilibre existe pour ce système qui minimise le coût pour tous les tenants. Nous étudions ensuite la coexistence d'URLLC avec d'autres services 5G, tels que le haut débit mobile amélioré eMBB (enhanced Mobile Broadband), dans le spectre non-licencié. eMBB a de grandes paquets et son multiplexage avec URLLC peut entraîner une forte dégradation des performances d'URLLC. Pour cela, nous proposons une nouvelle technique pour prioriser les paquets URLLC en les transmettant avec une puissance plus élevée. Cependant, la transmission à haute puissance n'est pas systématiquement effectuée afin de réduire les interférences sur les autres utilisateurs et aussi pour réduire la consommation d'énergie, ce qui est très important pour les appareils alimentés par batterie. Dans ce cas, deux méthodes ont été proposées pour transmettre avec une puissance élevée, en ne le laissant qu'en dernier recours. L'un est indépendant du LBT et transmet une fois le délai de paquet approche de l'expiration, tandis que l'autre respecte le LBT et n'utilise une puissance élevée que lorsque les opportunités de transmission se produisent au-delà d'un seuil de temps. Nous proposons ensuite une mise en œuvre décentralisée de l'approche par seuil de temps décrit ci-dessus. Nous formulons le problème dans le cadre d'optimisation où les émetteurs doivent choisir la politique optimale (seuil de temps) qui minimise la consommation d'énergie tout en préservant les exigences d'URLLC. Nous résolvons ensuite le problème d'optimisation en utilisant une approche d'apprentissage et montrons une lente convergence vers la politique optimale du fait que les pertes sont des événements rares. Pour y remédier, nous utilisons le cadre d'optimisation et la connaissance préalable du système pour accélérer cet apprentissage. Nous étudions enfin l'approche décentralisée pour un type différent de services critiques qui met l'accent sur la fraîcheur de l'information, connue sous le nom d'Age de l'Information (AoI). Dans ce contexte, au lieu de garantir une cible de fiabilité dans un délai, le paquet doit être livré dès sa génération, sinon sa valeur se dégrade. Nous démontrons que les politiques optimales dans le contexte AoI ont tendance à démarrer de manière agressive et à réduire la puissance de transmission lorsque l'âge du paquet augmenteThis thesis studies the transport of critical services in 5G networks, where unlicensed spectrum is advocated to minimize the cost and to cope with the high demand for frequency resources. We first evaluate the performance of Ultra-Reliable Low-Latency Communication (URLLC) which has stringent requirements on reliability and delay, on the order of 99.999% and 1 ms, respectively, transported in unlicensed spectrum. We propose a model based on a Markov chain to quantify the reliability within a delay constraint under Listen-Before-Talk (LBT) medium access procedure, then we deduce the maximum number of stations that can be handled at the same time, while respecting URLLC constraints. This analysis is then used to investigate novel methods for the joint transmission of URLLC over unlicensed and licensed spectrum. We propose three methods for the joint access to available resources, and demonstrate that the optimal method to access the resources is by using licensed ones only when unlicensed transmission fails within a given time budget. This method is then studied in the case of multiple tenants in proximity competing over the same unlicensed channel. If all tenants try to maximize their usage of unlicensed resources then everyone will end up in a tragedy of the commons type of situation. We show that at least one equilibrium point exists for this system which minimizes the cost for all tenants. We study later the coexistence of URLLC with other 5G services, such as enhanced Mobile Broadband (eMBB), in unlicensed spectrum. eMBB has large packets and its multiplexing with URLLC may entail a large degradation in URLLC performance. For that, we propose a new technique to prioritize URLLC packets by transmitting them with higher power. However, high power transmission is not systematically performed to reduce the interference on other users and also to reduce the energy consumption, which is very important for battery-powered devices. In this case, two methods were proposed to transmit with high power, leaving it as a last resort. One is LBT-agnostic and transmits whenever the packet delay approaches time-out, while the other respects LBT and uses high power only when transmission opportunities occur beyond a time threshold. We then propose a decentralized implementation of the time-threshold approach. We formulate the problem as an optimization problem where transmitters are to choose the optimal policy (time threshold) which minimizes the energy consumption while preserving URLLC requirements. We then solve the optimization problem using a learning approach and show a slow convergence to the optimal policy due to the fact that losses are rare events. To remedy to this, we employ the optimization framework and the prior knowledge of the system to accelerate this learning. We finally study the decentralized approach for a different type of critical services which focuses on the freshness of the information, known as the Age of Information (AoI). In this context, instead of guaranteeing a reliability target within a delay, the packet must be delivered as soon as it is generated, or else it loses its value. We demonstrate that optimal policies in the AoI context tend to start aggressively, and reduce the transmission power when the age of the packet increases
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Cook, Peta S. "Constructing and fracturing alliances : actant stories and the Australian xenotransplantation network." Thesis, Queensland University of Technology, 2008. https://eprints.qut.edu.au/18359/1/Peta_Cook_Thesis.pdf.
Full textAbstract:
Xenotransplantation (XTP; animal-to-human transplantation) is a controversial technology of contemporary scientific, medical, ethical and social debate in Australia and internationally. The complexities of XTP encompass immunology, immunosuppression, physiology, technology (genetic engineering and cloning), microbiology, and animal/human relations. As a result of these controversies, the National Health and Medical Research Council (NHMRC), Australia, formed the Xenotransplantation Working Party (XWP) in 2001. The XWP was designed to advise the NHMRC on XTP, if and how it should proceed in Australia, and to provide draft regulatory guidelines. During the period 2001-2004, the XWP produced three publicly available documents one of which, ‘Animal-to-Human Transplantation Research: A Guide for the Community’ (2003), was specifically designed to introduce the general public to the major issues and background of XTP. This thesis examines XTP in Australia as guided and influenced by this community document. Explicitly, drawing upon actor (actant)- network theory, I will reveal the Australian XTP network and explore, describe and explain XTP problematisations and network negotiations by the enrolled actants on two key concepts and obligatory passage points - animals and risk. These actants include those providing regulatory advice (members of the XWP and the associated Animal Issues Subcommittee), those developing and/or critiquing XTP (official science and scientists), and those targeted by the technology (people on dialysis, with Type-1 diabetes, Huntington’s disease, Parkinson’s disease, pre-or post-human-tohuman transplantation, and their partner/spouse). The stories are gathered through focus groups, semi-structured interviews and document analysis. They reveal ambiguous and sometimes contradictory stories about animals and risk, which influence and impact the problematisations of XTP and its networks. Therefore, XTP mobilises tension; facilitating both support and apprehension of the XTP network and its construction by both the sciences and the publics.
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Cook, Peta S. "Constructing and fracturing alliances : actant stories and the Australian xenotransplantation network." Queensland University of Technology, 2008. http://eprints.qut.edu.au/18359/.
Full textAbstract:
Xenotransplantation (XTP; animal-to-human transplantation) is a controversial technology of contemporary scientific, medical, ethical and social debate in Australia and internationally. The complexities of XTP encompass immunology, immunosuppression, physiology, technology (genetic engineering and cloning), microbiology, and animal/human relations. As a result of these controversies, the National Health and Medical Research Council (NHMRC), Australia, formed the Xenotransplantation Working Party (XWP) in 2001. The XWP was designed to advise the NHMRC on XTP, if and how it should proceed in Australia, and to provide draft regulatory guidelines. During the period 2001-2004, the XWP produced three publicly available documents one of which, ‘Animal-to-Human Transplantation Research: A Guide for the Community’ (2003), was specifically designed to introduce the general public to the major issues and background of XTP. This thesis examines XTP in Australia as guided and influenced by this community document. Explicitly, drawing upon actor (actant)- network theory, I will reveal the Australian XTP network and explore, describe and explain XTP problematisations and network negotiations by the enrolled actants on two key concepts and obligatory passage points - animals and risk. These actants include those providing regulatory advice (members of the XWP and the associated Animal Issues Subcommittee), those developing and/or critiquing XTP (official science and scientists), and those targeted by the technology (people on dialysis, with Type-1 diabetes, Huntington’s disease, Parkinson’s disease, pre-or post-human-tohuman transplantation, and their partner/spouse). The stories are gathered through focus groups, semi-structured interviews and document analysis. They reveal ambiguous and sometimes contradictory stories about animals and risk, which influence and impact the problematisations of XTP and its networks. Therefore, XTP mobilises tension; facilitating both support and apprehension of the XTP network and its construction by both the sciences and the publics.
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Kim, Hyun. "Reliable p-hub location problems and protection models for hub network design." The Ohio State University, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=osu1218159290.
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Brantley, Susan L., William H. McDowell, William E. Dietrich, Timothy S. White, Praveen Kumar, Suzanne P. Anderson, Jon Chorover, et al. "Designing a network of critical zone observatories to explore the living skin of the terrestrial Earth." COPERNICUS GESELLSCHAFT MBH, 2017. http://hdl.handle.net/10150/626604.
Full textAbstract:
The critical zone (CZ), the dynamic living skin of the Earth, extends from the top of the vegetative canopy through the soil and down to fresh bedrock and the bottom of the groundwater. All humans live in and depend on the CZ. This zone has three co-evolving surfaces: the top of the vegetative canopy, the ground surface, and a deep subsurface below which Earth's materials are unweathered. The network of nine CZ observatories supported by the US National Science Foundation has made advances in three broad areas of CZ research relating to the co-evolving surfaces. First, monitoring has revealed how natural and anthropogenic inputs at the vegetation canopy and ground surface cause subsurface responses in water, regolith structure, minerals, and biotic activity to considerable depths. This response, in turn, impacts aboveground biota and climate. Second, drilling and geophysical imaging now reveal how the deep subsurface of the CZ varies across landscapes, which in turn influences aboveground ecosystems. Third, several new mechanistic models now provide quantitative predictions of the spatial structure of the subsurface of the CZ.Many countries fund critical zone observatories (CZOs) to measure the fluxes of solutes, water, energy, gases, and sediments in the CZ and some relate these observations to the histories of those fluxes recorded in landforms, biota, soils, sediments, and rocks. Each US observatory has succeeded in (i) synthesizing research across disciplines into convergent approaches; (ii) providing long-term measurements to compare across sites; (iii) testing and developing models; (iv) collecting and measuring baseline data for comparison to catastrophic events; (v) stimulating new process-based hypotheses; (vi) catalyzing development of new techniques and instrumentation; (vii) informing the public about the CZ; (viii) mentoring students and teaching about emerging multidisciplinary CZ science; and (ix) discovering new insights about the CZ. Many of these activities can only be accomplished with observatories. Here we review the CZO enterprise in the United States and identify how such observatories could operate in the future as a network designed to generate critical scientific insights. Specifically, we recognize the need for the network to study network-level questions, expand the environments under investigation, accommodate both hypothesis testing and monitoring, and involve more stakeholders. We propose a driving question for future CZ science and a
hubs-and-campaignsmodel to address that question and target the CZ as one unit. Only with such integrative efforts will we learn to steward the life-sustaining critical zone now and into the future.
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Philippi, Carissa Louise. "The dynamic self: exploring the critical role of the default mode network in self-referential processing." Diss., University of Iowa, 2011. https://ir.uiowa.edu/etd/1254.
Full textAbstract:
Investigation of the neural correlates of the self has implicated a network of brain regions including the medial prefrontal cortex (MPFC), posterior cingulate (PCC), precuneus (pC), and inferior parietal lobule (IPL). At the same time, recent neuroimaging work has identified the Default Mode Network (DMN), a network of brain regions that are highly active at `rest' (without an active cognitive task). While the functional significance of the DMN remains unknown, converging evidence suggests that the DMN might be critical for self-referential processing (e.g., introspection). In this dissertation, I tested this hypothesis using a lesion approach. In the first experiment, I examined the critical role of the DMN hubs (MPFC, IPL) in autobiographical memory (AM) retrieval. I predicted that if the DMN hubs were critical for AM, then lesions to either the MPFC or IPL should result in AM retrieval impairments. I tested this prediction using the Iowa Autobiographical Memory Questionnaire (IAMQ), a questionnaire that assessed retrograde AM retrieval. In support of the prediction, lesions to the MPFC and IPL were associated with significant AM retrieval impairments. While not predicted, AM retrieval deficits were also associated with lesions in medial and lateral temporal cortices, regions also considered part of the DMN. In the second experiment, I tested the critical role of the DMN hubs in the self-reference effect (SRE), a well-known memory advantage conferred by self-related processing. I predicted that if the DMN hubs were critical for the SRE, then damage to the MPFC or IPL should diminish the effect. I used a standard personality trait judgment paradigm to test this prediction. In partial support of the prediction, I found that damage to the MPFC abolished the SRE with a "self" specific deficit. While IPL damage was associated with a diminished SRE, the effects were not significant. In the third experiment, I tested the hypothesis that the DMN is critical for accurate knowledge of one's personality. I predicted that if the DMN hubs are critical for accurate self-knowledge, then damage to either the MPFC or IPL should be associated with less accurate personality reports. In partial support of the prediction, MPFC and IPL groups demonstrated less accurate personality ratings. However, performance for all lesion groups was comparable and not significantly different from healthy subjects. In the fourth experiment, I sought to test the hypothesis that the DMN is critical for mind wandering (MW). I predicted that if the DMN hubs are critical for MW, then damage to the MPFC and IPL should result in decreased MW. To test this prediction, I used two approaches: 1) an experience sampling method (Sustained Attention to Response Task), and 2) a self-report measure (Imaginal Processes Inventory scale of MW). Contrary to my prediction, IPL lesions were associated with increased MW on the SART. By contrast, in support of the prediction, both MPFC and IPL lesions were associated with significant self-reported decreases in MW. Together, these experiments provide some evidence to support the hypothesis that the DMN is critical for self-referential processing. Future work might investigate the impact of DMN lesions on other self-processes (e.g., self-agency).
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Abed, Wathiq. "Robust fault analysis for permanent magnet DC motor in safety critical applications." Thesis, University of Plymouth, 2015. http://hdl.handle.net/10026.1/3550.
Full textAbstract:
Robust fault analysis (FA) including the diagnosis of faults and predicting their level of severity is necessary to optimise maintenance and improve reliability of Aircraft. Early diagnosis of faults that might occur in the supervised process renders it possible to perform important preventative actions. The proposed diagnostic models were validated in two experimental tests. The first test concerned a single localised and generalised roller element bearing fault in a permanent magnet brushless DC (PMBLDC) motor. Rolling element bearing defect is one of the main reasons for breakdown in electrical machines. Vibration and current are analysed under stationary and non-stationary load and speed conditions, for a variety of bearing fault severities, and for both local and global bearing faults. The second test examined the case of an unbalance rotor due to blade faults in a thruster, motor based on a permanent magnet brushed DC (PMBDC) motor. A variety of blade fault conditions were investigated, over a wide range of rotation speeds. The test used both discrete wavelet transform (DWT) to extract the useful features, and then feature reduction techniques to avoid redundant features. This reduces computation requirements and the time taken for classification by the application of an orthogonal fuzzy neighbourhood discriminant analysis (OFNDA) approach. The real time monitoring of motor operating conditions is an advanced technique that presents the real performance of the motor, so that the dynamic recurrent neural network (DRNN) proposed predicts the conditions of components and classifies the different faults under different operating conditions. The results obtained from real time simulation demonstrate the effectiveness and reliability of the proposed methodology in accurately classifying faults and predicting levels of fault severity.
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Zhang, Ran. "Decision Support Models for A Few Critical Problems in Transportation System Design and Operations." Scholar Commons, 2017. http://scholarcommons.usf.edu/etd/6669.
Full textAbstract:
Transportation system is one of the key functioning components of the modern society and plays an important role in the circulation of commodity and growth of economy. Transportation system is not only the major influencing factor of the efficiency of large-scale complex industrial logistics, but also closely related to everyone’s daily life. The goals of an ideal transportation system are focused on improving mobility, accessibility, safety, enhancing the coordination of different transportation modals and reducing the impact on the environment, all these activities require sophisticated design and plan that consider different factors, balance tradeoffs and maintaining efficiency. Hence, the design and planning of transportation system are strongly considered to be the most critical problems in transportation research.
Transportation system planning and design is a sequential procedure which generally contains two levels: strategic and operational. This dissertation conducts extensive research covering both levels, on the strategic planning level, two network design problems are studied and on the operational level, routing and scheduling problems are analyzed. The main objective of this study is utilizing operations research techniques to generate and provide managerial decision supports in designing reliable and efficient transportation system. Specifically, three practical problems in transportation system design and operations are explored. First, we collaborate with a public transit company to study the bus scheduling problem for a bus fleet with multiples types of vehicles. By considering different cost characteristics, we develop integer program and exact algorithm to efficiently solve the problem. Next, we examine the network design problem in emergency medical service and develop a novel two stage robust optimization framework to deal with uncertainty, then propose an approximate algorithm which is fast and efficient in solving practical instance. Finally, we investigate the major drawback of vehicle sharing program network design problem in previous research and provide a counterintuitive finding that could result in unrealistic solution. A new pessimistic model as well as a customized computational scheme are then introduced. We benchmark the performance of new model with existing model on several prototypical network structures. The results show that our proposed models and solution methods offer powerful decision support tools for decision makers to design, build and maintain efficient and reliable transportation systems.
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Granfeldt, Axel, and Max Nyqvist. "Fostering Network Effects : How to achieve user retention on multisided platforms." Thesis, Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-74361.
Full textAbstract:
Purpose – The purpose of this study is to increase the understanding of how multisided platforms (MSP) could retain different user groups on their platform. To fulfill the purpose, the following research questions (RQ) were derived: RQ 1: How could MSPs design their activities to retain users on the producer side(s)? and RQ 2: How could MSPs design their activities to retain users on the consumer side(s)? Method – This study was conducted as an abductive single case study based on a multisided platform developed within the health sector. In addition, complimentary interviews were conducted to validate and expand the result from the case study. In total, 15 interviews were conducted and analyzed through thematic analysis. Findings – The findings are presented in a framework showing what activities to conduct in certain stages of platform development and is divided between two distinct platform sides, producers and consumers. The different stages are relative to critical mass i.e. how many users the MSP has and shows which activities that is necessary in these stages. Theoretical implication and Practical implication – The study suggests activities necessary for retaining users on MSPs seen to certain stages of development. Additional contributions are (1) in the beginning, MSPs should initially focus on the platform side who provides the most viable product, (2) mass in users is a prerequisite for finding the right matches, and (3) “super-platforms” with many value offerings will be key for retaining users and long-term success. The practical implications are (1) which activities that are necessary on a certain side of the MSP, (2) guiding managers with which activities that are suitable in a certain stage of platform development, and (3) provide managers with the ability to plan future activities. Limitations and Future Research – This study is conducted in South-east Asia which implies that a similar study should be conducted in a western context. Furthermore, it is limited to a single-case study of an MSP, although there were exploratory and confirmative interviews with other companies. Future research should therefore include a multiple-case study to compare how different MSPs work with retention. Lastly, further studies into what critical mass is and how to estimate that, should be considered.
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Liu, Qingyun. "Statistical Process Control for the Fairness of Network Resource Distribution." FIU Digital Commons, 2011. http://digitalcommons.fiu.edu/etd/518.
Full textAbstract:
The purpose of this research is to develop a statistical method to monitor the fairness of network resource distribution. The newly developed fairness score function allows users to have the same or different priority levels. Especially, this function possesses all the necessary properties required as a quality characteristic for the purpose of statistical process control.
The main objective is to find the critical values for the statistical test. Monte Carlo simulation is used to find the critical values. When the users have the same priority level, a table of the critical values is given for different sample sizes and different significance levels. When the users have different priority levels, it is difficult to generate a similar table since the users’ priority levels vary. Therefore, the critical values are computed for given priority levels. In both cases, an example is given to demonstrate the approach developed in this study.
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Briglauer, Wolfgang, and Klaus Gugler. "A critical appraisal of the European Commission´s policy towards regulating next generation communications networks." Forschungsinstitut für Regulierungsökonomie, WU Vienna University of Economics and Business, 2012. http://epub.wu.ac.at/3642/1/briglauer_gugler_a_critical_appraisal.pdf.
Full textAbstract:
Fiber-deployment of telecommunications networks is currently a great challenge for sector-specific
regulators, national governments, as well as for investing operators. One of the most controversial
regulatory issues in Europe (and elsewhere) is whether the emerging next generation access (NGA)
infrastructure should be subjected to cost-based access regulation or whether at least a temporary
removal of ex ante obligations ("regulatory holidays") should be granted.
In answering this question we examine the current and foreseeable EU regulatory framework and
show that it does not provide positive incentives for NGA deployment and increasing penetration
rates. On the basis of an international comparison with the most recent data on NGA deployment and
penetration, it appears, in turn, that deregulatory and/or state aid driven approaches targeted at the
demand (subscribers) and supply side (coverage) are more promising. (author's abstract)Series: Working Papers / Research Institute for Regulatory Economics
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Magnini, Matteo. "An information theory analysis of critical Boolean networks as control software for robots." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021. http://amslaurea.unibo.it/23062/.
Full textAbstract:
This work is an analysis of critical random Boolean networks used as control software for robots. The main goal is to find if there are relations between information theory measures on robot's sensors and actuators and the capability of the robot to achieve a particular task. Secondary goals are to verify if just the number of nodes of the networks is significant to obtain better populations of controllers for a given task and if a Boolean network can perform well in more than one single task. Results show that for certain tasks there is a strongly positively correlation between some information theory measures and the objective function of the task. Moreover Boolean networks with an higher number of nodes tend to perform better. These results can be useful in the automatic design process of control software for robots. Finally some Boolean networks from a random generated population exhibit phenotypic plasticity, which is the ability to manifest more phenotypes from the same genotype in different environments. In this scenario it is the capability of the same Boolean network (same functions and connections) to successfully achieve different tasks.
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Garside, Victoria C. "Analysis of transcriptional targets of SOX9 during embryonic heart valve development reveals a critical network of transcription factors." Thesis, University of British Columbia, 2015. http://hdl.handle.net/2429/55600.
Full textAbstract:
Cardiac malformations affect approximately 1% of human newborns and a large number of these are due to defects in the heart valves and septum. It has been suggested that cardiac valve diseases, which make up about one third of all cardiovascular defects, arise from underlying developmental malformations that occur during embryogenesis. Interestingly, the development of the heart valves (cardiac cushions) and tissues that form cartilage templates (such as the limb) share a number of key TFs, such as TWIST1, SOX9, and NFATC1 suggesting that they have similar transcriptional programs. It has been proposed that regulatory networks involved in cartilage formation, are also active during valve development and disease. The transcription factor SOX9 has an essential role in heart valve and cartilage formation and its loss leads to major congenital abnormalities in the embryo. Regardless of this critical role, little is known about how SOX9 regulates heart valve development or its transcriptional targets. Therefore, to identify transcriptional targets of SOX9 and elucidate the role of SOX9 in the developing valves, we have used ChIP-Seq on the E12.5 atrioventricular canal (heart valves) and limb buds. Comparisons of SOX9DNA-binding regions among tissues revealed both context-dependent and context–independent SOX9 interacting regions. Context-independent SOX9 binding suggests that SOX9 may play a role in regulating proliferation-associated genes across many tissues. Generation of two endothelial specific Sox9 mutants uncovers two potential roles for SOX9 in heart valve formation: first in the initial formation of valve mesenchyme and later in the survival and differentiation of valve mesenchyme. Analysis of tissue-specific SOX9-DNA binding regions with gene expression profiles from Sox9 mutant heart valves indicates that SOX9 directly regulates a collection of transcription factors known to be important for heart development. Taken together, this study identified that SOX9 controls transcriptional hierarchies involved in proliferation across tissues and heart valve differentiation. SOX9 transcriptional targets identified in this data could be used as predictive factors of heart valve disease, or as targets for new therapeutic strategies for disease and congenital defects.Medicine, Faculty of
Graduate
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Schorn, Christoph Alexander [Verfasser], Gerd [Akademischer Betreuer] Ascheid, and Hans-Joachim [Akademischer Betreuer] Wunderlich. "Low-overhead fault tolerance for safety-critical neural network applications / Christoph Alexander Schorn ; Gerd Ascheid, Hans-Joachim Wunderlich." Aachen : Universitätsbibliothek der RWTH Aachen, 2020. http://d-nb.info/1220360171/34.
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Schorn, Christoph Alexander Verfasser], Gerd [Akademischer Betreuer] [Ascheid, and Hans-Joachim [Akademischer Betreuer] Wunderlich. "Low-overhead fault tolerance for safety-critical neural network applications / Christoph Alexander Schorn ; Gerd Ascheid, Hans-Joachim Wunderlich." Aachen : Universitätsbibliothek der RWTH Aachen, 2020. http://d-nb.info/1220360171/34.
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Hunter, Allison M. "News Is Beginning To Look A Lot Like Christmas: A Critical History of the Holiday Shopping Season and ABC Network's Nightly News." Ohio University / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1417782736.
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McDonald, James Franklin Jr. "Critical Technologies: The United States Department of Defense Efforts to Shape Technology Development After the Cold War - A Discourse and Network Analysis." Diss., Virginia Tech, 2014. http://hdl.handle.net/10919/56625.
Full textAbstract:
Each year the Department of Defense spends over $10 billion on its science and technology development efforts. While deemed an investment by proponents (and beneficiaries) technology development programs are particularly vulnerable in times of budget cuts. As the government moves forward with efforts to reduce spending the Department of Defense will be pressed to sustain current levels of spending on technology efforts. This situation is similar to the post-Cold War phase in defense planning when savings in spending were sought as a peace dividend. This dissertation examines the Department of Defense efforts during 1989-1992 to define certain technologies as critical to national security. Inherent in the effort to identify critical technologies was the desire to articulate technology ideology; to establish asymmetries of power and resources; and to patrol the boundaries of policy and responsibility. The questions are: What are the ideologies associated with technology development planning? What are the discursive mechanisms used to secure and reinforce power? And, what evidence of boundary work and network construction emerges from the examination? First, I distill from four years of defense technology planning documentation the explicit ideologies, the ideologies masked in metaphor, and the discourse strategies used to secure and sustain power. Following the deconstruction of the discursive elements I use Science and Technology Studies tools including boundary work, boundary objects, the Social Construction of Technology, and network theory, to further understand the heterogeneous process of defense technology development planning. The tools help explain the mechanisms by which elements of Department of Defense technology development form a connected structure. Finally, the examination yields a spherical network model for innovation that addresses the weaknesses of prior innovation network models. I conclude that in the face of uncertain budgets, technology planning relies upon ideology, power strategies, and boundary-work to build a network that protects funding and influence. In the current budget climate it will be interesting to see if the strategies are resurrected. The examination should be of interest to both the Science and Technology Studies scholar and the policy practitioner. And hopefully, the review will stimulate further examination and debate.Ph. D.