917 resultados para NETWORK ANALYSIS
Resumo:
Healthy brain functioning depends on efficient communication of information between brain regions, forming complex networks. By quantifying synchronisation between brain regions, a functionally connected brain network can be articulated. In neurodevelopmental disorders, where diagnosis is based on measures of behaviour and tasks, a measure of the underlying biological mechanisms holds promise as a potential clinical tool. Graph theory provides a tool for investigating the neural correlates of neuropsychiatric disorders, where there is disruption of efficient communication within and between brain networks. This research aimed to use recent conceptualisation of graph theory, along with measures of behaviour and cognitive functioning, to increase understanding of the neurobiological risk factors of atypical development. Using magnetoencephalography to investigate frequency-specific temporal dynamics at rest, the research aimed to identify potential biological markers derived from sensor-level whole-brain functional connectivity. Whilst graph theory has proved valuable for insight into network efficiency, its application is hampered by two limitations. First, its measures have hardly been validated in MEG studies, and second, graph measures have been shown to depend on methodological assumptions that restrict direct network comparisons. The first experimental study (Chapter 3) addressed the first limitation by examining the reproducibility of graph-based functional connectivity and network parameters in healthy adult volunteers. Subsequent chapters addressed the second limitation through adapted minimum spanning tree (a network analysis approach that allows for unbiased group comparisons) along with graph network tools that had been shown in Chapter 3 to be highly reproducible. Network topologies were modelled in healthy development (Chapter 4), and atypical neurodevelopment (Chapters 5 and 6). The results provided support to the proposition that measures of network organisation, derived from sensor-space MEG data, offer insights helping to unravel the biological basis of typical brain maturation and neurodevelopmental conditions, with the possibility of future clinical utility.
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A tanulmány Magyarország egyik legnagyobb foglalkoztatójának megrendelésére készült abból a célból, hogy milyen megoldásokkal lehetne a vállalati működést hatékonyabbá tenni. Ennek keretében a szerzők megvizsgálták, hol tart ma a HR adatbányászati kutatás a világban. Milyen eszközök állnak rendelkezésre ahhoz, hogy a munkavállalói elmenetelt előre jelezzék, illetve figyeljék, valamint milyen lehetőség van a hálózati kutatások felhasználására a biztonság területén. Szerencsés, hogy a vállalkozói kérdések és erőforrások találkozhattak a kutatói szféra aktuális kutatási területeivel. A tanulmány szerzői úgy gondolják, hogy a cikkben megfogalmazott állítások, következtetések, eredmények a jövőben hasznosíthatók lesznek a vállalat és más cégek számára is. _____ The authors were pleased to take part in this research project initiated by one of Hungary’s largest employer. The goal of the project was to work out BI solutions to improve upon their business process. In the framework of the project first the authors made a survey on the current trends in the world of HR datamining. They reviewed the available tools for the prediction of employee promotion and investigated the question on how to utilize results achieved in social network analysis in the field of enterprise security. When real business problems and resources meet the mainstream research of the scientific community it is always a fortunate and it is rather fruitful. The authors are certain that the results published in this document will be beneficial for Foxconn in the near future. Of course, they are not done. There are continually new research perspectives opening up and huge amount of information is accumulating in the enterprises just waiting for getting discovered and analysed. Also the environment in which an enterprise operates is dynamically changing and thus the company faces new challenges and new type of business problems arise. The authors are in the hope that their research experience will help decision makers also in the future to solve real world business problems.
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Network analysis has emerged as a key technique in communication studies, economics, geography, history and sociology, among others. A fundamental issue is how to identify key nodes in a network, for which purpose a number of centrality measures have been developed. This paper proposes a new parametric family of centrality measures called generalized degree. It is based on the idea that a relationship to a more interconnected node contributes to centrality in a greater extent than a connection to a less central one. Generalized degree improves on degree by redistributing its sum over the network with the consideration of the global structure. Application of the measure is supported by a set of basic properties. A sufficient condition is given for generalized degree to be rank monotonic, excluding counter-intuitive changes in the centrality ranking after certain modifications of the network. The measure has a graph interpretation and can be calculated iteratively. Generalized degree is recommended to apply besides degree since it preserves most favorable attributes of degree, but better reflects the role of the nodes in the network and has an increased ability to distinguish between their importance.
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The Internet has become an integral part of our nation’s critical socio-economic infrastructure. With its heightened use and growing complexity however, organizations are at greater risk of cyber crimes. To aid in the investigation of crimes committed on or via the Internet, a network forensics analysis tool pulls together needed digital evidence. It provides a platform for performing deep network analysis by capturing, recording and analyzing network events to find out the source of a security attack or other information security incidents. Existing network forensics work has been mostly focused on the Internet and fixed networks. But the exponential growth and use of wireless technologies, coupled with their unprecedented characteristics, necessitates the development of new network forensic analysis tools. This dissertation fostered the emergence of a new research field in cellular and ad-hoc network forensics. It was one of the first works to identify this problem and offer fundamental techniques and tools that laid the groundwork for future research. In particular, it introduced novel methods to record network incidents and report logged incidents. For recording incidents, location is considered essential to documenting network incidents. However, in network topology spaces, location cannot be measured due to absence of a ‘distance metric’. Therefore, a novel solution was proposed to label locations of nodes within network topology spaces, and then to authenticate the identity of nodes in ad hoc environments. For reporting logged incidents, a novel technique based on Distributed Hash Tables (DHT) was adopted. Although the direct use of DHTs for reporting logged incidents would result in an uncontrollably recursive traffic, a new mechanism was introduced that overcome this recursive process. These logging and reporting techniques aided forensics over cellular and ad-hoc networks, which in turn increased their ability to track and trace attacks to their source. These techniques were a starting point for further research and development that would result in equipping future ad hoc networks with forensic components to complement existing security mechanisms.
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The etiology of central nervous system tumors (CNSTs) is mainly unknown. Aside from extremely rare genetic conditions, such as neurofibromatosis and tuberous sclerosis, the only unequivocally identified risk factor is exposure to ionizing radiation, and this explains only a very small fraction of cases. Using meta-analysis, gene networking and bioinformatics methods, this dissertation explored the hypothesis that environmental exposures produce genetic and epigenetic alterations that may be involved in the etiology of CNSTs. A meta-analysis of epidemiological studies of pesticides and pediatric brain tumors revealed a significantly increased risk of brain tumors among children whose mothers had farm-related exposures during pregnancy. A dose response was recognized when this risk estimate was compared to those for risk of brain tumors from maternal exposure to non-agricultural pesticides during pregnancy, and risk of brain tumors among children exposed to agricultural activities. Through meta-analysis of several microarray studies which compared normal tissue to astrocytomas, we were able to identify a list of 554 genes which were differentially expressed in the majority of astrocytomas. Many of these genes have in fact been implicated in development of astrocytoma, including EGFR, HIF-1α, c-Myc, WNT5A, and IDH3A. Reverse engineering of these 554 genes using Bayesian network analysis produced a gene network for each grade of astrocytoma (Grade I-IV), and ‘key genes’ within each grade were identified. Genes found to be most influential to development of the highest grade of astrocytoma, Glioblastoma multiforme (GBM) were: COL4A1, EGFR, BTF3, MPP2, RAB31, CDK4, CD99, ANXA2, TOP2A, and SERBP1. Lastly, bioinformatics analysis of environmental databases and curated published results on GBM was able to identify numerous potential pathways and geneenvironment interactions that may play key roles in astrocytoma development. Findings from this research have strong potential to advance our understanding of the etiology and susceptibility to CNSTs. Validation of our ‘key genes’ and pathways could potentially lead to useful tools for early detection and novel therapeutic options for these tumors.
Resumo:
The Internet has become an integral part of our nation's critical socio-economic infrastructure. With its heightened use and growing complexity however, organizations are at greater risk of cyber crimes. To aid in the investigation of crimes committed on or via the Internet, a network forensics analysis tool pulls together needed digital evidence. It provides a platform for performing deep network analysis by capturing, recording and analyzing network events to find out the source of a security attack or other information security incidents. Existing network forensics work has been mostly focused on the Internet and fixed networks. But the exponential growth and use of wireless technologies, coupled with their unprecedented characteristics, necessitates the development of new network forensic analysis tools. This dissertation fostered the emergence of a new research field in cellular and ad-hoc network forensics. It was one of the first works to identify this problem and offer fundamental techniques and tools that laid the groundwork for future research. In particular, it introduced novel methods to record network incidents and report logged incidents. For recording incidents, location is considered essential to documenting network incidents. However, in network topology spaces, location cannot be measured due to absence of a 'distance metric'. Therefore, a novel solution was proposed to label locations of nodes within network topology spaces, and then to authenticate the identity of nodes in ad hoc environments. For reporting logged incidents, a novel technique based on Distributed Hash Tables (DHT) was adopted. Although the direct use of DHTs for reporting logged incidents would result in an uncontrollably recursive traffic, a new mechanism was introduced that overcome this recursive process. These logging and reporting techniques aided forensics over cellular and ad-hoc networks, which in turn increased their ability to track and trace attacks to their source. These techniques were a starting point for further research and development that would result in equipping future ad hoc networks with forensic components to complement existing security mechanisms.
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This work examines atiku-euiash (caribou meat) sharing practices in Sheshatshiu, Newfoundland and Labrador, and aims to elucidate an overarching question: how do sharing practices participate in the co-constitution of the Innu ‘social’? The ‘social’ is understood in this work as a descriptor that refers to the emergent properties of the Innu collective. The thesis is that sharing practices participate in the co-constitution of the Innu social and enact its boundaries. Inside these boundaries, atiku-euiash is more than simply a food resource: by realizing Innu values of generosity, respect and autonomy, sharing implicates the associations of human, animal, and animal masters that constitute the Innu world. Sharing is connected with the enskilment of the younger generations by their el-ders, and thus with the reproduction of Innu values through time. The ways of sharing are relevant because changes in such practices affect the constitution of the Innu social. Giv-en Euro-Canadian colonization, the Innu are in a fraught social space in which sharing is interrupted by colonization practices and values. Understanding sharing is necessary to develop policies that do not interrupt the reproduction of the Innu world This work uses several research methods: participant observation, sharing surveys, and interviews. It also uses network analysis as sharing practices leave traces of giving and receiving actions and these traces can be represented as a network of givers, receivers and circulating caribou meat. There are two main ways in which caribou is hunted and shared: household-based hunts and community-based hunts. The household-based hunts are organized by the hunters themselves, who are able and willing to hunt. Community-based hunts are completely organized and funded by the SIFN or the Innu Nation. In or-der to understand the differences in the distribution of the two hunt types, the categories of centrality and clustering are used to show how the flow of atiku-eiuash and its associ-ated realization of values and enskilment correlate with different degrees of centralization inside the sharing clusters.
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Acknowledgements MW and RVD have been supported by the German Federal Ministry for Education and Research via the BMBF Young Investigators Group CoSy-CC2 (grant 18 Marc Wiedermann et al. no. 01LN1306A). JFD thanks the Stordalen Foundation and BMBF (project GLUES) for financial support. JK acknowledges the IRTG 1740 funded by DFG and FAPESP. Coupled climate network analysis has been performed using the Python package pyunicorn (Donges et al, 2015a) that is available at https://github.com/pik-copan/pyunicorn.
Resumo:
Acknowledgements MW and RVD have been supported by the German Federal Ministry for Education and Research via the BMBF Young Investigators Group CoSy-CC2 (grant 18 Marc Wiedermann et al. no. 01LN1306A). JFD thanks the Stordalen Foundation and BMBF (project GLUES) for financial support. JK acknowledges the IRTG 1740 funded by DFG and FAPESP. Coupled climate network analysis has been performed using the Python package pyunicorn (Donges et al, 2015a) that is available at https://github.com/pik-copan/pyunicorn.
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Purpose: This paper aims to explore the role of internal and external knowledgebased linkages across the supply chain in achieving better operational performance. It investigates how knowledge is accumulated, shared, and applied to create organization-specific knowledge resources that increase and sustain the organization's competitive advantage. Design/methodology/approach: This paper uses a single case study with multiple, embedded units of analysis, and the social network analysis (SNA) to demonstrate the impact of internal and external knowledge-based linkages across multiple tiers in the supply chain on the organizational operational performance. The focal company of the case study is an Italian manufacturer supplying rubber components to European automotive enterprises. Findings: With the aid of the SNA, the internal knowledge-based linkages can be mapped and visualized. We found that the most central nodes having the most connections with other nodes in the linkages are the most crucial members in terms of knowledge exploration and exploitation within the organization. We also revealed that the effective management of external knowledge-based linkages, such as buyer company, competitors, university, suppliers, and subcontractors, can help improve the operational performance. Research limitations/implications: First, our hypothesis was tested on a single case. The analysis of multiple case studies using SNA would provide a deeper understanding of the relationship between the knowledge-based linkages at all levels of the supply chain and the integration of knowledge. Second, the static nature of knowledge flows was studied in this research. Future research could also consider ongoing monitoring of dynamic linkages and the dynamic characteristic of knowledge flows. Originality/value: To the best of our knowledge, the phrase 'knowledge-based linkages' has not been used in the literature and there is lack of investigation on the relationship between the management of internal and external knowledge-based linkages and the operational performance. To bridge the knowledge gap, this paper will show the importance of understanding the composition and characteristics of knowledge-based linkages and their knowledge nodes. In addition, this paper will show that effective management of knowledge-based linkages leads to the creation of new knowledge and improves organizations' operational performance.
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Ostensibly, BITs are the ideal international treaty. First, until just recently, they almost uniformly came with explicit dispute resolution mechanisms through which countries could face real costs for violation (Montt 2009). Second, the signing, ratification, and violation of them are easily accessible public knowledge. Thus countries presumably would face reputational costs for violating these agreements. Yet, these compliance devices have not dissuaded states from violating these agreements. Even more interestingly, in recent years, both developed and developing countries have moved towards modifying the investor-friendly provisions of these agreements. These deviations from the expectations of the credible commitment argument raise important questions about the field's assumptions regarding the ability of international treaties with commitment devices to effectively constrain state behavior.
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This thesis reports on an exploratory study of the relationship between the Internet and women’s empowerment in China. The theoretical framework of the study combines feminist theorisations of power – the core concept of empowerment – with insights from sociological perspectives on power and gender, as well as collective action theory. This allows for the conceptualisation of women’s empowerment as a dynamic process that is shaped by a set of communicative practices. Focusing on female Chinese bloggers and women’s groups of different organisational types, this study aims to explore the respective ways in which these two types of women actors use the Internet with a view to examining whether, and the extent to which it enables them to generate a sense of empowerment. The empirical data mainly derives from interviews with female bloggers and with staff members from different women’s groups, as well as from a features analysis and social network analysis of the sampled blogs and official websites of studied groups. Overall, the findings suggest that the opportunities offered by the Internet for women’s empowerment through awareness-raising, social interactions, and the organising of collective action, are limited. For female bloggers, their activities do not translate the new communicative practices afforded by the Internet into concrete action to bring about changes in their everyday life. On the contrary, blogs become an alternative platform to discipline their behaviours and to reinforce patriarchal gendered norms. Moreover, the research finds that the promise of empowerment is further undermined by the pervasive commercialisation of the Internet and state control. For women’s groups, contextual factors prevent them from fully realising the potential of the Internet for increasing their organisational visibility, promoting public awareness about gender issues, building a sense of the collective, campaigning, or networking. The major barriers in these processes are state control, a lack of resources, online censorship, and at times, competition from commercial sites. In this respect, the Internet does not play a significant role in forming a collective to challenge existing unjust power relations.
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This article presents a methodological proposition to map the diversity of the audiovisual industry in the digital scenario by portraying the most important interactions between those who create, produce, distribute and disseminate audiovisual productions on line, paying special attention to powerful intermediaries and to small and medium independent agents. Taking as a point of departure a flexible understanding of social network analysis, the aim is to understand the structure of the audiovisual industry on the internet so that, taking into consideration a given sector, agents, their relations and the networks they give place to – as well as the structural conditions under which they operate – are studied. The aim is to answer questions such as: what is mapping, what is of interesting to map, how can it be done and what advantages and disadvantages the results will present.
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Las relaciones públicas se configuran como una actividad esencial en la gestión de la comunicación con los públicos de los clubes de fútbol ya que son muy activos y su grado de reactividad es alto. Con este texto se analiza el papel que desempeñan las redes sociales en los clubes de fútbol que poseen mayor número de ingresos. Para ello, se desarrolla una metodología que estudia qué presencia tienen en las redes sociales, el número de seguidores, qué grado de interacción se produce entre clubes y públicos y los contenidos y las temáticas de los textos de las redes sociales. Los resultados muestran un público activo pero con intervenciones relacionadas con los resultados futbolísticos y una gestión comunicativa unidireccional por parte de los clubes.
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Este artículo presenta una investigación en la que se analizan las dificultades del profesorado para planificar, coordinar y evaluar competencias claves en una muestra de 23 centros educativos. El tema tiene hondas repercusiones ya que una mala praxis educativa de las competencias claves puede conculcar uno de los derechos fundamentales del alumnado a ser evaluado de forma objetiva (LODE: Art.6b y RD 732/1995: Art. 13.1) y poder superar las pruebas de evaluación consideradas necesarias para la obtención del título académico mínimo que otorga el estado español. La investigación se ha desarrollado desde una doble perspectiva metodológica; en primer lugar, es una investigación descriptiva en la que presentamos las características fundamentales de las competencias claves y la normativa básica para su desarrollo y evaluación. En segundo lugar, aplicamos un procedimiento de análisis con una doble vertiente cualitativa mediante el empleo del programa Atlas-Ti y del enfoque reticular-categorial del análisis de redes sociales con la aplicación de UCINET y el visor yED Graph Editor para abordar el análisis de las principales dificultades y obstáculos detectados. Los resultados muestran que existen serias dificultades en las tres dimensiones analizadas: "planificación", "coordinación" y "evaluación" de competencias clave; especialmente en la necesidad de formación del profesorado, en la evaluación de las competencias, en la metodología para su desarrollo y en los procesos de coordinación interna para su consecución en los centros educativos.