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Statistical detection with weak signals via regularizationLi, Jinzheng 01 July 2012 (has links)
There has been an increasing interest in uncovering smuggled nuclear materials associated with the War on Terror. Detection of special nuclear materials hidden in cargo containers is a major challenge in national and international security. We propose a new physics-based method to determine the presence of the spectral signature of one or more nuclides from a poorly resolved spectra with weak signatures. The method is different from traditional methods that rely primarily on peak finding algorithms. The new approach considers each of the signatures in the library to be a linear combination of subspectra. These subspectra are obtained by assuming a signature consisting of just one of the unique gamma rays emitted by the nuclei. We propose a Poisson regression model for deducing which nuclei are present in the observed spectrum. In recognition that a radiation source generally comprises few nuclear materials, the underlying Poisson model is sparse, i.e. most of the regression coefficients are zero (positive coefficients correspond to the presence of nuclear materials). We develop an iterative algorithm for a penalized likelihood estimation that prompts sparsity. We illustrate the efficacy of the proposed method by simulations using a variety of poorly resolved, low signal-to-noise ratio (SNR) situations, which show that the proposed approach enjoys excellent empirical performance even with SNR as low as to -15db. The proposed method is shown to be variable-selection consistent, in the framework of increasing detection time and under mild regularity conditions.
We study the problem of testing for shielding, i.e. the presence of intervening materials that attenuate the gamma ray signal. We show that, as detection time increases to infinity, the Lagrange multiplier test, the likelihood ratio test and Wald test are asymptotically equivalent, under the null hypothesis, and their asymptotic null distribution is Chi-square. We also derived the local power of these tests.
We also develop a nonparametric approach for detecting spectra indicative of the presence of SNM. This approach characterizes the shape change in a spectrum from background radiation. We do this by proposing a dissimilarity function that characterizes the complete shape change of a spectrum from the background, over all energy channels. We derive the null asymptotic test distributions in terms of functionals of the Brownian bridge. Simulation results show that the proposed approach is very powerful and promising for detecting weak signals. It is able to accurately detect weak signals with SNR as low as -37db.
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Zdroj modulačního signálu pro mikrovlnný maják / Modulation signal source for microwave beaconBelloň, Michal January 2013 (has links)
This project is focused on construction of source of modulation signal for microwave beacon. The output signal is the same as signal, which is generated by PC software WSJT (Weak Signal by Joe Taylor) on PC sound card output. Signal on device output is modulated using by WSJT modulation and its specific JT4 mode. The device output has I and Q components of signal.
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Dsenvolvimento da capacidade absortiva em processos de exploração de sinais fracos, sob a perspectiva da criação do conhecimento organizacionalBortoli, Luciana Nogueira January 2016 (has links)
Diversos estudos exploram temas relacionados ao monitoramento do ambiente com o intuito de auxiliar empresas a se protegerem contra ameaças e a aproveitarem oportunidades provenientes do ambiente externo. Outros pesquisadores se dedicaram aos tópicos relacionados à gestão do conhecimento, colocando o conhecimento como elemento central para o desenvolvimento e o sucesso empresarial. Contudo, identificaram-se poucos estudos que explorem as temáticas de monitoramento do ambiente e gestão do conhecimento em conjunto. Com o propósito de contribuir para o preenchimento desta lacuna, o presente estudo investiga o desenvolvimento da capacidade absortiva em processos de exploração de sinais fracos, sob a perspectiva da criação do conhecimento organizacional. Para tal investigação se utilizou método qualitativo e exploratório; tendo como técnicas de coleta de dados entrevistas semiestruturadas e análise de conteúdo para exploração dos mesmos. Constatou-se que o desempenho do processo de Inteligência pode contribuir para o desenvolvimento da capacidade absortiva, além de propiciar a criação, expansão e renovação de conhecimentos individuais e organizacionais. Observou-se, também, que a realização das atividades de Inteligência incentiva a ação e influencia na tomada de decisão de colaboradores e gestores. Os profissionais ao se sentirem melhor informados sobre oportunidades e ameaças provenientes do ambiente externo à organização passam a refletir e se responsabilizar mais por ações e decisões. / Many studies explore topics related to the environmental scanning process in order to assist companies with protecting themselves against threats and seizing opportunities that arise from external environments. Furthermore, a number of researchers have focused broadly and deeply on topics related to knowledge management, placing knowledge as a central resource to a business’s development and success. Nevertheless, there are few studies that combine the themes of environmental scanning and knowledge management. Aiming contribute to fill this gap, this study investigates the absorptive capacity developing in weak signals’ exploration process through the organization knowledge creation’ perspectives. The employed method to this qualitative and explorative research will be interviews by means of techniques for collecting data; and a content analysis for an exploitation of these data. It was found that the Intelligence process performance contributes to the development of absorptive capacity. Futhermore, the practice of Intelligence process facilitates the creation, expansion and renewal of individual and organizational knowledge. It was also observed that the realization of intelligence activities encourages action and influence in employees and managers decision making. Professionals who feel better informed about opportunities and threats from the external environment in regards to the organization start to further reflect and be more accountable for actions and decisions.
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Dsenvolvimento da capacidade absortiva em processos de exploração de sinais fracos, sob a perspectiva da criação do conhecimento organizacionalBortoli, Luciana Nogueira January 2016 (has links)
Diversos estudos exploram temas relacionados ao monitoramento do ambiente com o intuito de auxiliar empresas a se protegerem contra ameaças e a aproveitarem oportunidades provenientes do ambiente externo. Outros pesquisadores se dedicaram aos tópicos relacionados à gestão do conhecimento, colocando o conhecimento como elemento central para o desenvolvimento e o sucesso empresarial. Contudo, identificaram-se poucos estudos que explorem as temáticas de monitoramento do ambiente e gestão do conhecimento em conjunto. Com o propósito de contribuir para o preenchimento desta lacuna, o presente estudo investiga o desenvolvimento da capacidade absortiva em processos de exploração de sinais fracos, sob a perspectiva da criação do conhecimento organizacional. Para tal investigação se utilizou método qualitativo e exploratório; tendo como técnicas de coleta de dados entrevistas semiestruturadas e análise de conteúdo para exploração dos mesmos. Constatou-se que o desempenho do processo de Inteligência pode contribuir para o desenvolvimento da capacidade absortiva, além de propiciar a criação, expansão e renovação de conhecimentos individuais e organizacionais. Observou-se, também, que a realização das atividades de Inteligência incentiva a ação e influencia na tomada de decisão de colaboradores e gestores. Os profissionais ao se sentirem melhor informados sobre oportunidades e ameaças provenientes do ambiente externo à organização passam a refletir e se responsabilizar mais por ações e decisões. / Many studies explore topics related to the environmental scanning process in order to assist companies with protecting themselves against threats and seizing opportunities that arise from external environments. Furthermore, a number of researchers have focused broadly and deeply on topics related to knowledge management, placing knowledge as a central resource to a business’s development and success. Nevertheless, there are few studies that combine the themes of environmental scanning and knowledge management. Aiming contribute to fill this gap, this study investigates the absorptive capacity developing in weak signals’ exploration process through the organization knowledge creation’ perspectives. The employed method to this qualitative and explorative research will be interviews by means of techniques for collecting data; and a content analysis for an exploitation of these data. It was found that the Intelligence process performance contributes to the development of absorptive capacity. Futhermore, the practice of Intelligence process facilitates the creation, expansion and renewal of individual and organizational knowledge. It was also observed that the realization of intelligence activities encourages action and influence in employees and managers decision making. Professionals who feel better informed about opportunities and threats from the external environment in regards to the organization start to further reflect and be more accountable for actions and decisions.
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Dsenvolvimento da capacidade absortiva em processos de exploração de sinais fracos, sob a perspectiva da criação do conhecimento organizacionalBortoli, Luciana Nogueira January 2016 (has links)
Diversos estudos exploram temas relacionados ao monitoramento do ambiente com o intuito de auxiliar empresas a se protegerem contra ameaças e a aproveitarem oportunidades provenientes do ambiente externo. Outros pesquisadores se dedicaram aos tópicos relacionados à gestão do conhecimento, colocando o conhecimento como elemento central para o desenvolvimento e o sucesso empresarial. Contudo, identificaram-se poucos estudos que explorem as temáticas de monitoramento do ambiente e gestão do conhecimento em conjunto. Com o propósito de contribuir para o preenchimento desta lacuna, o presente estudo investiga o desenvolvimento da capacidade absortiva em processos de exploração de sinais fracos, sob a perspectiva da criação do conhecimento organizacional. Para tal investigação se utilizou método qualitativo e exploratório; tendo como técnicas de coleta de dados entrevistas semiestruturadas e análise de conteúdo para exploração dos mesmos. Constatou-se que o desempenho do processo de Inteligência pode contribuir para o desenvolvimento da capacidade absortiva, além de propiciar a criação, expansão e renovação de conhecimentos individuais e organizacionais. Observou-se, também, que a realização das atividades de Inteligência incentiva a ação e influencia na tomada de decisão de colaboradores e gestores. Os profissionais ao se sentirem melhor informados sobre oportunidades e ameaças provenientes do ambiente externo à organização passam a refletir e se responsabilizar mais por ações e decisões. / Many studies explore topics related to the environmental scanning process in order to assist companies with protecting themselves against threats and seizing opportunities that arise from external environments. Furthermore, a number of researchers have focused broadly and deeply on topics related to knowledge management, placing knowledge as a central resource to a business’s development and success. Nevertheless, there are few studies that combine the themes of environmental scanning and knowledge management. Aiming contribute to fill this gap, this study investigates the absorptive capacity developing in weak signals’ exploration process through the organization knowledge creation’ perspectives. The employed method to this qualitative and explorative research will be interviews by means of techniques for collecting data; and a content analysis for an exploitation of these data. It was found that the Intelligence process performance contributes to the development of absorptive capacity. Futhermore, the practice of Intelligence process facilitates the creation, expansion and renewal of individual and organizational knowledge. It was also observed that the realization of intelligence activities encourages action and influence in employees and managers decision making. Professionals who feel better informed about opportunities and threats from the external environment in regards to the organization start to further reflect and be more accountable for actions and decisions.
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Aide à la prise de décision stratégique : détection de données pertinentes de sources numériques sur Internet / Support strategic decision making : detection of relevant data from digital sources on the InternetBuitrago Hurtado, Alex Fernando 22 October 2014 (has links)
Le domaine de notre recherche est la décision stratégique au sein des organisations. Plus précisément il s'agit de l'aide à la prise de décision stratégique et de la problématique de l'acquisition des informations utiles pour de telles décisions. D'un côté les ‘informations de terrain' issus des contacts entre personnes, des réunions professionnelles, etc. demeurent essentielles pour les dirigeants. D'un autre côté les journaux quotidiens nationaux et internationaux fournissent un volume considérable de données que l'on peut qualifier de données brutes (Raw data). Mais, outre ces sources classiques, le recueil des informations a évolué de façon considérable avec l'avènement des technologies de l'information et notamment de l'Internet pour ce qui concerne dans notre recherche. Nous avons choisi le domaine concernant l'acquisition des informations de terrain fournies par les journaux nationaux quotidiens : les journaux quotidiens colombiens pour ce qui concernera notre étude empirique. Pour acquérir cette information nous avons proposé sur la base d'une recherche du type « Action Design Research », de concevoir, de construire et d'expérimenter un artéfact permettant de détecter des signaux faibles potentiels issus des données extraites d'Internet et qui aideraient les dirigeants de l'entreprise à découvrir et comprendre leur environnement. L'artéfact a été conçu et construit en deux phases utilisant des concepts théoriques liés à la surcharge de données, à la veille stratégique notamment la VAS-IC® (Veille Anticipative Stratégique – Intelligence Collective) et sur les caractéristiques souhaitables des systèmes informatisés d'aide à la décision stratégique. Après sa construction, l'artéfact a été expérimenté sur un terrain permettant d'évaluer son effectivité. Cette expérimentation a permis d'améliorer nos connaissances sur la pertinence des données numériques dans le processus de la prise de la décision. Les décideurs impliqués ont également pu d'intégrer des nouvelles pratiques adaptées à leurs besoins d'information. / Our research area is around the strategic decision within organizations. More precisely, it is applicable as an aid for strategic decision-making and detecting useful information for such decisions. On the one hand, the ‘information from the field' from the contacts between individuals, business meetings, etc. is always essential for managers. On the other hand, national and international newspapers can provide a considerable volume of data that can be defined as the raw data. However, besides these classical sources, gathering information has changed dramatically with the advent of information technology and particularly internet that is related to our research. We chose the area for the acquisition of ‘information from the field' provided by the national daily newspapers: the Colombian newspaper which concerns to our empirical study. In order to detect weak signals of potential internet base issues which help managers to discover and understand their environment, we proposed a research based on “Action Design Research” type and then applied for designing, building and testing an artifact to gain the required information. The artifact has been designed and built in two phases that is included of using theoretical concepts about the data overload, environmental scanning particularly the “anticipatory and collective environmental scanning model” (VAS-IC®) and the desirable characteristics of strategic decision making support systems. After its construction, the artifact applied to real experimentation that has allowed us to evaluate its effectiveness. Afterwards, we improved our knowledge about the relevance of digital data in the decision making process. The results of all the involved decision makers have been able to integrate these new practices into their information needs.
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Technology-Scanning Capability and Market-Scanning Capability as Drivers of Product Innovation PerformanceAlam, Md Shahedul 09 August 2011 (has links)
Changing trends in customer preference, competitors’ offerings, new technologies and development techniques may disrupt a firm from its current leading market position and may favor other firms that prioritize innovation. Once a market opportunity is identified (i.e., find an answer to the ‘what to do’ question), firms need to engage in a series of activities and information processing to determine an appropriate way to monetize that opportunity – that is, firms need to find an answer to the ‘how to do’ question. Alternately, a firm may first identify a technological opportunity (i.e. find an answer to the ‘how to do’) and then find a market opportunity (i.e. find an answer to the ‘what to do’ question) to make use of the technological opportunity. Two scales that measure the capabilities of firms to address the following two questions – ‘what to do’ and ‘how to do’ - were reported; these were labelled as market-scanning capability (MktScan) and technology-scanning capability (TechScan); and these two scales were also tested in a broader research model.
In turbulent environments, marketing and R&D become more challenging, since they face an uncertain future. Firms need to learn systemic scanning and decoding of apparently random changes in their business environment and imagine a pattern that makes sense. One cannot plan for uncertainty. A better strategy is to be prepared for it. One way to prepare is to develop the capabilities that would help the firm to become more adaptive. Drucker (1992) also argued that instead of planning for the long term that is uncertain, firms needed to become adaptive to tackle uncertainty. The ability of a firm to adapt to the changes depends on its ability to sense the nature of the changes in its business environment and respond to those. Sense-and-respond framework (Haeckel 1999; Haeckel 2000; Day and Schoemaker 2006) was proposed to emphasize the identification of weak signals (Ansoff 1975) to tackle increased uncertainty in business environment. In current days, effectiveness of firm’s activities often depends on the richness of its sources of information and its capability to process the collected information to identify the patterns of change happening in its business environments. Information processing may happen in two dimensions: in market dimension and in technology dimension. Firms’ capabilities for information collecting and processing in these two dimensions were measured using two firm-level constructs. These are market-scanning capability and technology-scanning capability.
Resource-based theory helped to understand how firms use their tangible and intangible resources to compete in the market. Specific problem-solving aspects of the processes, activities, and cultural norms enable firms to make decisions about engaging the available resources and capabilities in ways that maximize customer value, by realizing the identified opportunities into product and service offerings. This research identified the characteristic strength of this problem-solving approach of firms – collecting information both internally and externally about possible market opportunities and technological options, organization-wide processing of that information, and taking actions to respond using insights gained – as two latent constructs called ‘market-scanning capability’ and ‘technology-scanning capability’.
The concepts of ‘market-scanning capability’ and ‘technology-scanning capability’ were first defined and then, scales were developed to enable researchers and managers to measure these firm-level constructs. Next, the predictive roles of these capabilities on firm performance were examined. Empirical analysis for scale development and validation of the research model were performed with data collected through a web-based survey of Canadian manufacturing firms.
Firm performance was captured in two stages – first, by product innovation performance, and second, by overall firm performance. Product innovation performance was used as an intermediate performance measure to examine the direct influence on it of market-scanning capability and technology-scanning capability, and then, to relate product innovation performance to final business outcome measured using ‘overall firm performance’ scale. The study validated the notion of resource-based theory by supporting the belief that higher levels of market-scanning capability and technology-scanning capability would lead to improved product innovation performance. The role of environmental turbulence was also examined for its possible moderating effect. Two measures of environmental turbulence, namely, technology and market turbulence were used to test the moderation effect. The technology turbulence construct was found to have a moderating effect on the relationship between technology-scanning capability and product innovation performance, indicating that firms needed to focus more attention on the changes in the technology landscape when turbulence in the technological field was perceived to be higher, in order to keep the same level of product innovation performance.
Insight gained from the study contributed to a knowledge-base that might be useful to both practitioners and researchers. The combination of TechScan and MktScan scales could be used as a benchmark tool by managers to assess firms’ readiness to take advantage of the opportunities that existed. On the theoretical side, the study contributed to the understanding by showing that both market-scanning capability and technology-scanning capability had direct and indirect influences on firm performance. Also, it was found that the indirect influence of a certain scanning capability became important when firms were pre-disposed to emphasize the other scanning capability.
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Technology-Scanning Capability and Market-Scanning Capability as Drivers of Product Innovation PerformanceAlam, Md Shahedul 09 August 2011 (has links)
Changing trends in customer preference, competitors’ offerings, new technologies and development techniques may disrupt a firm from its current leading market position and may favor other firms that prioritize innovation. Once a market opportunity is identified (i.e., find an answer to the ‘what to do’ question), firms need to engage in a series of activities and information processing to determine an appropriate way to monetize that opportunity – that is, firms need to find an answer to the ‘how to do’ question. Alternately, a firm may first identify a technological opportunity (i.e. find an answer to the ‘how to do’) and then find a market opportunity (i.e. find an answer to the ‘what to do’ question) to make use of the technological opportunity. Two scales that measure the capabilities of firms to address the following two questions – ‘what to do’ and ‘how to do’ - were reported; these were labelled as market-scanning capability (MktScan) and technology-scanning capability (TechScan); and these two scales were also tested in a broader research model.
In turbulent environments, marketing and R&D become more challenging, since they face an uncertain future. Firms need to learn systemic scanning and decoding of apparently random changes in their business environment and imagine a pattern that makes sense. One cannot plan for uncertainty. A better strategy is to be prepared for it. One way to prepare is to develop the capabilities that would help the firm to become more adaptive. Drucker (1992) also argued that instead of planning for the long term that is uncertain, firms needed to become adaptive to tackle uncertainty. The ability of a firm to adapt to the changes depends on its ability to sense the nature of the changes in its business environment and respond to those. Sense-and-respond framework (Haeckel 1999; Haeckel 2000; Day and Schoemaker 2006) was proposed to emphasize the identification of weak signals (Ansoff 1975) to tackle increased uncertainty in business environment. In current days, effectiveness of firm’s activities often depends on the richness of its sources of information and its capability to process the collected information to identify the patterns of change happening in its business environments. Information processing may happen in two dimensions: in market dimension and in technology dimension. Firms’ capabilities for information collecting and processing in these two dimensions were measured using two firm-level constructs. These are market-scanning capability and technology-scanning capability.
Resource-based theory helped to understand how firms use their tangible and intangible resources to compete in the market. Specific problem-solving aspects of the processes, activities, and cultural norms enable firms to make decisions about engaging the available resources and capabilities in ways that maximize customer value, by realizing the identified opportunities into product and service offerings. This research identified the characteristic strength of this problem-solving approach of firms – collecting information both internally and externally about possible market opportunities and technological options, organization-wide processing of that information, and taking actions to respond using insights gained – as two latent constructs called ‘market-scanning capability’ and ‘technology-scanning capability’.
The concepts of ‘market-scanning capability’ and ‘technology-scanning capability’ were first defined and then, scales were developed to enable researchers and managers to measure these firm-level constructs. Next, the predictive roles of these capabilities on firm performance were examined. Empirical analysis for scale development and validation of the research model were performed with data collected through a web-based survey of Canadian manufacturing firms.
Firm performance was captured in two stages – first, by product innovation performance, and second, by overall firm performance. Product innovation performance was used as an intermediate performance measure to examine the direct influence on it of market-scanning capability and technology-scanning capability, and then, to relate product innovation performance to final business outcome measured using ‘overall firm performance’ scale. The study validated the notion of resource-based theory by supporting the belief that higher levels of market-scanning capability and technology-scanning capability would lead to improved product innovation performance. The role of environmental turbulence was also examined for its possible moderating effect. Two measures of environmental turbulence, namely, technology and market turbulence were used to test the moderation effect. The technology turbulence construct was found to have a moderating effect on the relationship between technology-scanning capability and product innovation performance, indicating that firms needed to focus more attention on the changes in the technology landscape when turbulence in the technological field was perceived to be higher, in order to keep the same level of product innovation performance.
Insight gained from the study contributed to a knowledge-base that might be useful to both practitioners and researchers. The combination of TechScan and MktScan scales could be used as a benchmark tool by managers to assess firms’ readiness to take advantage of the opportunities that existed. On the theoretical side, the study contributed to the understanding by showing that both market-scanning capability and technology-scanning capability had direct and indirect influences on firm performance. Also, it was found that the indirect influence of a certain scanning capability became important when firms were pre-disposed to emphasize the other scanning capability.
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