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Sample records for firm agent network

  1. Response of firm agent network to exogenous shock

    NASA Astrophysics Data System (ADS)

    Ikeda, Yuichi; Aoyama, Hideaki; Iyetomi, Hiroshi; Fujiwara, Yoshi; Souma, Wataru; Kaizoji, Taisei

    2007-08-01

    This paper describes an agent-based model of interacting firms, in which interacting firm agents rationally invest capital and labor in order to maximize payoff. Both transactions and production are taken into account in this model. First, the performance of individual firms on a real transaction network was simulated. The simulation quantitatively reproduced the cumulative probability distribution of revenue, material cost, capital, and labor. Then, the response of the firms to a given exogenous shock, defined as a sudden change of gross domestic product, is discussed. The longer tail in cumulative probability and skewed distribution of growth rate are observed for a high growth scenario.

  2. Bank-Firm Credit Network in Japan: An Analysis of a Bipartite Network

    PubMed Central

    Marotta, Luca; Miccichè, Salvatore; Fujiwara, Yoshi; Iyetomi, Hiroshi; Aoyama, Hideaki; Gallegati, Mauro; Mantegna, Rosario N.

    2015-01-01

    We investigate the networked nature of the Japanese credit market. Our investigation is performed with tools of network science. In our investigation we perform community detection with an algorithm which is identifying communities composed of both banks and firms. We show that the communities obtained by directly working on the bipartite network carry information about the networked nature of the Japanese credit market. Our analysis is performed for each calendar year during the time period from 1980 to 2011. To investigate the time evolution of the networked structure of the credit market we introduce a new statistical method to track the time evolution of detected communities. We then characterize the time evolution of communities by detecting for each time evolving set of communities the over-expression of attributes of firms and banks. Specifically, we consider as attributes the economic sector and the geographical location of firms and the type of banks. In our 32-year-long analysis we detect a persistence of the over-expression of attributes of communities of banks and firms together with a slow dynamic of changes from some specific attributes to new ones. Our empirical observations show that the credit market in Japan is a networked market where the type of banks, geographical location of firms and banks, and economic sector of the firm play a role in shaping the credit relationships between banks and firms. PMID:25933413

  3. Bank-firm credit network in Japan: an analysis of a bipartite network.

    PubMed

    Marotta, Luca; Miccichè, Salvatore; Fujiwara, Yoshi; Iyetomi, Hiroshi; Aoyama, Hideaki; Gallegati, Mauro; Mantegna, Rosario N

    2015-01-01

    We investigate the networked nature of the Japanese credit market. Our investigation is performed with tools of network science. In our investigation we perform community detection with an algorithm which is identifying communities composed of both banks and firms. We show that the communities obtained by directly working on the bipartite network carry information about the networked nature of the Japanese credit market. Our analysis is performed for each calendar year during the time period from 1980 to 2011. To investigate the time evolution of the networked structure of the credit market we introduce a new statistical method to track the time evolution of detected communities. We then characterize the time evolution of communities by detecting for each time evolving set of communities the over-expression of attributes of firms and banks. Specifically, we consider as attributes the economic sector and the geographical location of firms and the type of banks. In our 32-year-long analysis we detect a persistence of the over-expression of attributes of communities of banks and firms together with a slow dynamic of changes from some specific attributes to new ones. Our empirical observations show that the credit market in Japan is a networked market where the type of banks, geographical location of firms and banks, and economic sector of the firm play a role in shaping the credit relationships between banks and firms.

  4. Adaptive networks of trading agents.

    PubMed

    Burda, Z; Krzywicki, A; Martin, O C

    2008-10-01

    Multiagent models have been used in many contexts to study generic collective behavior. Similarly, complex networks have become very popular because of the diversity of growth rules giving rise to scale-free behavior. Here we study adaptive networks where the agents trade "wealth" when they are linked together while links can appear and disappear according to the wealth of the corresponding agents; thus the agents influence the network dynamics and vice versa. Our framework generalizes a multiagent model of Bouchaud and Mézard [Physica A 282, 536 (2000)], and leads to a steady state with fluctuating connectivities. The system spontaneously self-organizes into a critical state where the wealth distribution has a fat tail and the network is scale free; in addition, network heterogeneities lead to enhanced wealth condensation.

  5. Debt-credit Economic Networks of Banks and Firms: the Italian Case

    NASA Astrophysics Data System (ADS)

    De Masi, Giulia; Gallegati, Mauro

    A first analysis of the Italian system of banks and firms was carried out using an approach based on network theory. The emerging architecture of this economic network shows peculiar behaviors. Big banks are creditors of many firms; among these, big firms are financed by several banks. On the contrary, small firms are preferentially financed by small banks, covering very often the entire credit they need.

  6. Innovation Agents: Vocational Education and Training Skills and Innovation in Australian Industries and Firms. Volume 2

    ERIC Educational Resources Information Center

    Toner, Phillip; Marceau, Jane; Hall, Richard; Considine, Gillian

    2004-01-01

    This volume is a companion to "Innovation Agents: VET Skills and Innovation in Australian Industries and Firms. Volume 1". The detailed report of the project is contained in Volume 1 while Volume 2 contains the appendices: (1) Data tables for construction of the composite index of innovation; (2) Case study interview schedule; and (3)…

  7. Firm-stakeholder connectedness in the deregulating electric utility business: Exchange relationships in a network context

    NASA Astrophysics Data System (ADS)

    Heuer, Mark Alan

    2001-12-01

    This dissertation extends current research on firm-stakeholder relationships by proposing a stakeholder connectedness model in a network context involving the deregulating electric utility industry. Connectedness involves the degree to which firms and stakeholders form dependent-interdependent relationships in a network context. First, this dissertation suggests that firm-stakeholder relationships are multilateral and multidirectional. Evolving business practices increasingly involve models in which firms and stakeholders are connected through complex dependent-interdependent exchange relationships. Depending on the type of exchange involved, these relationships often are multilateral and multidirectional, particularly in a network context. Second, this dissertation presents a network-based model in which the degree of connectedness among firms and stakeholders are defined based on types of dependence-interdependence. Recognizing the social and economic nature of exchange among firms and stakeholders, this paper suggests that differing types of trust and control can effectively describe both dependence-interdependence and the degree of connectedness among firms and stakeholders. Third, this dissertation suggests that, from the perspective of exchange relationships in a network environment, power-based relationships provide only a partial explanation of firm-stakeholder interaction. This dissertation conceptualizes power as a subset of dependent-interdependent relationships and one of several factors that influence connectedness among firms and stakeholders in a network. The general proposition of this paper is that firms increasingly are interconnected through exchange relationships. Connectedness among firms and stakeholders in a network can be developed and maintained more effectively when based on long-term relationships. To support this proposition, models of differing types of firm-stakeholder connectedness are provided. Through case study research of firms

  8. Inter-firm Networks, Organizational Learning and Knowledge Updating: An Empirical Study

    NASA Astrophysics Data System (ADS)

    Zhang, Su-rong; Wang, Wen-ping

    In the era of knowledge-based economy which information technology develops rapidly, the rate of knowledge updating has become a critical factor for enterprises to gaining competitive advantage .We build an interactional theoretical model among inter-firm networks, organizational learning and knowledge updating thereby and demonstrate it with empirical study at last. The result shows that inter-firm networks and organizational learning is the source of knowledge updating.

  9. The origin of asymmetric behavior of money flow in the business firm network

    NASA Astrophysics Data System (ADS)

    Miura, W.; Takayasu, H.; Takayasu, M.

    2012-09-01

    In the business firm network, the number of in-degrees and out-degrees show the same scale-free property, however, the distribution of authorities and hubs show asymmetric behavior. Here we show the result of an analysis of the two-link structure of the network to find the origin of this asymmetric behavior. We find the tendency for big construction firms intermediating small subcontracting firms to have higher hub degrees. By measuring the strength of preferential attachment rate of new companies, we also find a abnormally strong preferential attachment for which the exponent is 1.4 with respect to out-degree when a new company forms a business partnership with a construction company. We propose a new model that reproduces the asymmetric behavior of the degrees of authorities and hubs by changing the preferential attachment rate between the in-degree and the out-degree in the business firm network.

  10. Mean field approximation for biased diffusion on Japanese inter-firm trading network.

    PubMed

    Watanabe, Hayafumi

    2014-01-01

    By analysing the financial data of firms across Japan, a nonlinear power law with an exponent of 1.3 was observed between the number of business partners (i.e. the degree of the inter-firm trading network) and sales. In a previous study using numerical simulations, we found that this scaling can be explained by both the money-transport model, where a firm (i.e. customer) distributes money to its out-edges (suppliers) in proportion to the in-degree of destinations, and by the correlations among the Japanese inter-firm trading network. However, in this previous study, we could not specifically identify what types of structure properties (or correlations) of the network determine the 1.3 exponent. In the present study, we more clearly elucidate the relationship between this nonlinear scaling and the network structure by applying mean-field approximation of the diffusion in a complex network to this money-transport model. Using theoretical analysis, we obtained the mean-field solution of the model and found that, in the case of the Japanese firms, the scaling exponent of 1.3 can be determined from the power law of the average degree of the nearest neighbours of the network with an exponent of -0.7.

  11. Moving beyond Stylized Economic Network Models: The Hybrid World of the Indian Firm Ownership Network1

    PubMed Central

    Mani, Dalhia; Moody, James

    2014-01-01

    A central theme of economic sociology has been to highlight the complexity and diversity of real world markets, but many network models of economic social structure ignore this feature and rely instead on stylized one-dimensional characterizations. Here, the authors return to the basic insight of structural diversity in economic sociology. Using the Indian interorganizational ownership network as their case, they discover a composite—or “hybrid”—model of economic networks that combines elements of prior stylized models. The network contains a disconnected periphery conforming closely to a “transactional” model; a semiperiphery characterized by small, dense clusters with sporadic links, as predicted in “small-world” models; and finally a nested core composed of clusters connected via multiple independent paths. The authors then show how a firm’s position within the mesolevel structure is associated with demographic features such as age and industry and differences in the extent to which firms engage in multiplex and high-value exchanges. PMID:25418990

  12. Credit risk enhancement in a network of interdependent firms

    NASA Astrophysics Data System (ADS)

    Neu, Peter; Kühn, Reimer

    2004-11-01

    We generalize existing structural models for credit risk to capture the impact of counterparty defaults on economic capital allocated to banks’ loan portfolios. Exploring the analogy to a lattice gas model from physics, correlations between sequential defaults are modeled as due to functionally defined, heterogeneous couplings between mutually dependent counterparties. We show that-already for moderate micro-economic dependencies-counterparty risk results in a fattening of the tails in the portfolio loss distribution. In particular, for stronger mutually supportive relationship between the firms, collective phenomena such as bursts and avalanches of defaults can be observed in the model. In this context, traditional credit risk models are inadequate because they underestimate the required capital buffer. Our model setting is particularly applicable for doing stress analyses of credit risk in loan portfolios.

  13. Community Structure of a Bank-Firm Credit Network in Japan

    NASA Astrophysics Data System (ADS)

    Iyetomi, Hiroshi; Matsuura, Yuki

    2014-03-01

    We study temporal change of community structure in a Japanese credit network formed by banks and listed firms through their financial relations over the last 30 years. The credit connectedness is regarded as a potenital source of systemic risk. Our network is a bipartite graph consisting of two species of nodes connected with bidirectional links. The direction of links is identified with that of risk flows and their weights are relative credit/loan with respect to the targets. In a partial credit network obtained only with the links pointing from firms toward banks, the city banks forms one major community in most of the time period to share risk when firms go wrong. On the other hand, a partial network only with the links from banks toward firms is decomposed into communities of similar size each of which has its own city bank, reflecting the main-bank system in Japan. Finally we take overlapping parts of the two community sets to find cores of the risk concentration in the credit network. This work was supported by JSPS KAKENHI Grant Number 22300080.

  14. Enhancing Inter-Firm Networks and Interorganizational Strategies. Research in Management Consulting Series.

    ERIC Educational Resources Information Center

    Buono, Anthony F., Ed.

    This book contain papers 13 papers on enhancing inter-firm networks, including by intervening in mergers and acquisitions and developing strategic alliances and partnerships. The following papers are included: "Introduction" (Anthony F. Buono); "Making Mergers and Acquisitions Work: A Guide to Consulting Interventions" (Mitchell Lee Marks);…

  15. Enhancing Inter-Firm Networks and Interorganizational Strategies. Research in Management Consulting Series.

    ERIC Educational Resources Information Center

    Buono, Anthony F., Ed.

    This book contain papers 13 papers on enhancing inter-firm networks, including by intervening in mergers and acquisitions and developing strategic alliances and partnerships. The following papers are included: "Introduction" (Anthony F. Buono); "Making Mergers and Acquisitions Work: A Guide to Consulting Interventions" (Mitchell Lee Marks);…

  16. Assessing the Liquidity of Firms: Robust Neural Network Regression as an Alternative to the Current Ratio

    NASA Astrophysics Data System (ADS)

    de Andrés, Javier; Landajo, Manuel; Lorca, Pedro; Labra, Jose; Ordóñez, Patricia

    Artificial neural networks have proven to be useful tools for solving financial analysis problems such as financial distress prediction and audit risk assessment. In this paper we focus on the performance of robust (least absolute deviation-based) neural networks on measuring liquidity of firms. The problem of learning the bivariate relationship between the components (namely, current liabilities and current assets) of the so-called current ratio is analyzed, and the predictive performance of several modelling paradigms (namely, linear and log-linear regressions, classical ratios and neural networks) is compared. An empirical analysis is conducted on a representative data base from the Spanish economy. Results indicate that classical ratio models are largely inadequate as a realistic description of the studied relationship, especially when used for predictive purposes. In a number of cases, especially when the analyzed firms are microenterprises, the linear specification is improved by considering the flexible non-linear structures provided by neural networks.

  17. Biased diffusion on the Japanese inter-firm trading network: estimation of sales from the network structure

    NASA Astrophysics Data System (ADS)

    Watanabe, Hayafumi; Takayasu, Hideki; Takayasu, Misako

    2012-04-01

    To investigate the actual phenomenon of transport on a complex network, we analysed empirical data for an inter-firm trading network, which consists of about one million Japanese firms, and the sales of these firms (a sale corresponds to the total in-flow into a node). First, we analysed the relationships between sales and sales of nearest neighbourhoods, from which we obtained a simple linear relationship between sales and the weighted sum of sales of nearest neighbourhoods (i.e. customers). In addition, we introduced a simple money transport model that is coherent with this empirical observation. In this model, a firm (i.e. customer) distributes money to its out-edges (suppliers) in proportion to the in-degree of destinations. From intensive numerical simulations, we found that the steady flows derived from these models can approximately reproduce the distribution of sales of actual firms. The sales of individual firms deduced from the money-transport model are shown to be proportional, on an average, to the real sales.

  18. Scale-free models for the structure of business firm networks.

    PubMed

    Kitsak, Maksim; Riccaboni, Massimo; Havlin, Shlomo; Pammolli, Fabio; Stanley, H Eugene

    2010-03-01

    We study firm collaborations in the life sciences and the information and communication technology sectors. We propose an approach to characterize industrial leadership using k -shell decomposition, with top-ranking firms in terms of market value in higher k -shell layers. We find that the life sciences industry network consists of three distinct components: a "nucleus," which is a small well-connected subgraph, "tendrils," which are small subgraphs consisting of small degree nodes connected exclusively to the nucleus, and a "bulk body," which consists of the majority of nodes. Industrial leaders, i.e., the largest companies in terms of market value, are in the highest k -shells of both networks. The nucleus of the life sciences sector is very stable: once a firm enters the nucleus, it is likely to stay there for a long time. At the same time we do not observe the above three components in the information and communication technology sector. We also conduct a systematic study of these three components in random scale-free networks. Our results suggest that the sizes of the nucleus and the tendrils in scale-free networks decrease as the exponent of the power-law degree distribution lambda increases, and disappear for lambda>or=3 . We compare the k -shell structure of random scale-free model networks with two real-world business firm networks in the life sciences and in the information and communication technology sectors. We argue that the observed behavior of the k -shell structure in the two industries is consistent with the coexistence of both preferential and random agreements in the evolution of industrial networks.

  19. Agent of Whirling Disease Meets Orphan Worm: Phylogenomic Analyses Firmly Place Myxozoa in Cnidaria

    PubMed Central

    Nesnidal, Maximilian P.; Helmkampf, Martin; Bruchhaus, Iris; El-Matbouli, Mansour; Hausdorf, Bernhard

    2013-01-01

    Myxozoa are microscopic obligate endoparasites with complex live cycles. Representatives are Myxobolus cerebralis, the causative agent of whirling disease in salmonids, and the enigmatic “orphan worm” Buddenbrockia plumatellae parasitizing in Bryozoa. Originally, Myxozoa were classified as protists, but later several metazoan characteristics were reported. However, their phylogenetic relationships remained doubtful. Some molecular phylogenetic analyses placed them as sister group to or even within Bilateria, whereas the possession of polar capsules that are similar to nematocysts of Cnidaria and of minicollagen genes suggest a close relationship between Myxozoa and Cnidaria. EST data of Buddenbrockia also indicated a cnidarian origin of Myxozoa, but were not sufficient to reject a closer relationship to bilaterians. Phylogenomic analyses of new genomic sequences of Myxobolus cerebralis firmly place Myxozoa as sister group to Medusozoa within Cnidaria. Based on the new dataset, the alternative hypothesis that Myxozoa form a clade with Bilateria can be rejected using topology tests. Sensitivity analyses indicate that this result is not affected by long branch attraction artifacts or compositional bias. PMID:23382916

  20. Agent of whirling disease meets orphan worm: phylogenomic analyses firmly place Myxozoa in Cnidaria.

    PubMed

    Nesnidal, Maximilian P; Helmkampf, Martin; Bruchhaus, Iris; El-Matbouli, Mansour; Hausdorf, Bernhard

    2013-01-01

    Myxozoa are microscopic obligate endoparasites with complex live cycles. Representatives are Myxobolus cerebralis, the causative agent of whirling disease in salmonids, and the enigmatic "orphan worm" Buddenbrockia plumatellae parasitizing in Bryozoa. Originally, Myxozoa were classified as protists, but later several metazoan characteristics were reported. However, their phylogenetic relationships remained doubtful. Some molecular phylogenetic analyses placed them as sister group to or even within Bilateria, whereas the possession of polar capsules that are similar to nematocysts of Cnidaria and of minicollagen genes suggest a close relationship between Myxozoa and Cnidaria. EST data of Buddenbrockia also indicated a cnidarian origin of Myxozoa, but were not sufficient to reject a closer relationship to bilaterians. Phylogenomic analyses of new genomic sequences of Myxobolus cerebralis firmly place Myxozoa as sister group to Medusozoa within Cnidaria. Based on the new dataset, the alternative hypothesis that Myxozoa form a clade with Bilateria can be rejected using topology tests. Sensitivity analyses indicate that this result is not affected by long branch attraction artifacts or compositional bias.

  1. Using Mobile Agents and Overlay Networks to Secure Electrical Networks

    SciTech Connect

    Dawes, Neal A.; Prosser, Bryan J.; Fulp, Errin W.; McKinnon, Archibald D.

    2013-02-11

    ABSTRACT The use of wandering, mobile agents can provide a robust approach for managing, monitoring, and securing electrical distribution networks. However, the topological structure of electrical networks can affect system performance. For example, if the multi-agent system relies on a regular inspection rate (on average, points of interest are inspected with equal frequency), then locations that are not well connected will on average be inspected less frequently. This paper discusses creation and use of overlay networks that create a virtual grid graph can provide faster coverage and a more uniform average agent sampling rate. Using overlays agents wander a virtual neighborhood consisting of only points of interest that are interconnected in a regular fashion (each point has the same number of neighbors). Experimental results will show that an overlay can often provide better network coverage and a more uniform inspection rate, which can improve cyber security by providing a faster detection of threats.

  2. Networks based on collisions among mobile agents

    NASA Astrophysics Data System (ADS)

    González, Marta C.; Lind, Pedro G.; Herrmann, Hans J.

    2006-12-01

    We investigate in detail a recent model of colliding mobile agents [M.C. González, P.G. Lind, H.J. Herrmann, Phys. Rev. Lett. 96 (2006) 088702. cond-mat/0602091], used as an alternative approach for constructing evolving networks of interactions formed by collisions governed by suitable dynamical rules. The system of mobile agents evolves towards a quasi-stationary state which is, apart from small fluctuations, well characterized by the density of the system and the residence time of the agents. The residence time defines a collision rate, and by varying this collision rate, the system percolates at a critical value, with the emergence of a giant cluster whose critical exponents are the ones of two-dimensional percolation. Further, the degree and clustering coefficient distributions, and the average path length, show that the network associated with such a system presents non-trivial features which, depending on the collision rules, enables one not only to recover the main properties of standard networks, such as exponential, random and scale-free networks, but also to obtain other topological structures. To illustrate, we show a specific example where the obtained structure has topological features which characterize the structure and evolution of social networks accurately in different contexts, ranging from networks of acquaintances to networks of sexual contacts.

  3. Estimation of Flux Between Interacting Nodes on Huge Inter-Firm Networks

    NASA Astrophysics Data System (ADS)

    Tamura, Koutarou; Miura, Wataru; Takayasu, Misako; Takayasu, Hideki; Kitajima, Satoshi; Goto, Hayato

    We analyze Japanese inter-firm network data showing scale-free properties as an example of a real complex network. The data contains information on money flow (annual transaction volume) between about 7000 pairs of firms. We focus on this money-flow data and investigate the correlation between various quantities such as sales or link numbers. We find that the flux from a buyer to a supplier is given by the product of the fractional powers of both sales with different exponents. This result indicates that the principle of detailed balance does not hold in the real transport of money; therefore, random walk type transport models such as PageRank are not suitable.

  4. Semantic agent technologies for tactical sensor networks

    NASA Astrophysics Data System (ADS)

    Jiang, Guofei; Chung, Wayne W.; Cybenko, George

    2003-09-01

    Recent advances in wireless communication and microelectronics have enabled the development of low-cost sensor devices leading to interest in large-scale sensor networks for military applications. Sensor networks consist of large numbers of networked sensors that can be dynamically deployed and used for tactical situational awareness. One critical challenge is how to dynamically integrate these sensor networks with information fusion processes to support real-time sensing, exploitation and decision-making in a rich tactical environment. In this paper, we describe our work on an extensible prototype to address the challenge. The prototype and its constituent technologies provide a proof-of-concept that demonstrates several fundamental new approaches for implementing next generation battlefield information systems. Many cutting-edge technologies are used to implement this system, including semantic web, web services, peer-to-peer network and content-based routing. This prototype system is able to dynamically integrate various distributed sensors and multi-level information fusion services into new applications and run them across a distributed network to support different mission goals. Agent technology plays a role in two fundamental ways: resources are described, located and tasked using semantic descriptions based on ontologies and semantic services; tracking, fusion and decision-making logic is implemented using agent objects and semantic descriptions as well.

  5. Motif formation and industry specific topologies in the Japanese business firm network

    NASA Astrophysics Data System (ADS)

    Maluck, Julian; Donner, Reik V.; Takayasu, Hideki; Takayasu, Misako

    2017-05-01

    Motifs and roles are basic quantities for the characterization of interactions among 3-node subsets in complex networks. In this work, we investigate how the distribution of 3-node motifs can be influenced by modifying the rules of an evolving network model while keeping the statistics of simpler network characteristics, such as the link density and the degree distribution, invariant. We exemplify this problem for the special case of the Japanese Business Firm Network, where a well-studied and relatively simple yet realistic evolving network model is available, and compare the resulting motif distribution in the real-world and simulated networks. To better approximate the motif distribution of the real-world network in the model, we introduce both subgraph dependent and global additional rules. We find that a specific rule that allows only for the merging process between nodes with similar link directionality patterns reduces the observed excess of densely connected motifs with bidirectional links. Our study improves the mechanistic understanding of motif formation in evolving network models to better describe the characteristic features of real-world networks with a scale-free topology.

  6. The network secrets of great change agents.

    PubMed

    Battilana, Julie; Casciaro, Tiziana

    2013-01-01

    Change is hard, especially in a large organization. Yet some leaders succeed--often spectacularly--at transforming their workplaces. what makes them able to exert this sort of influence when the vast majority can't? The authors tracked 68 change initiatives in the UK's National Health Service, an organization whose size, complexity, and tradition can make reform difficult. They discovered several predictors of change agents' success--all of which emphasize the importance of networks of personal relationships: Change agents who were central in the organization's informal network had a clear advantage, regardless of their position in the formal hierarchy. People who bridged disconnected groups or individuals were more effective at implementing dramatic reforms. The resisters in their networks did not necessarily know one another and so were unlikely to form a coalition. Change agents with cohesive networks, in which all individuals were connected, were better at instituting minor changes. Their contacts rallied around the initiative and helped convince others of its importance. Being close to people who were ambivalent about a change was always beneficial. In the end, fence-sitters were reluctant to disappoint a friend. But close relationships with resisters were a double-edged sword: Such ties helped push through minor initiatives but were a hindrance when attempting major change.

  7. Transportation dynamics on networks of mobile agents.

    PubMed

    Yang, Han-Xin; Wang, Wen-Xu; Xie, Yan-Bo; Lai, Ying-Cheng; Wang, Bing-Hong

    2011-01-01

    Most existing works on transportation dynamics focus on networks of a fixed structure, but networks whose nodes are mobile have become widespread, such as cell-phone networks. We introduce a model to explore the basic physics of transportation on mobile networks. Of particular interest is the dependence of the throughput on the speed of agent movement and the communication range. Our computations reveal a hierarchical dependence for the former, while an algebraic power law is found between the throughput and the communication range with the exponent determined by the speed. We develop a physical theory based on the Fokker-Planck equation to explain these phenomena. Our findings provide insights into complex transportation dynamics arising commonly in natural and engineering systems.

  8. Transportation dynamics on networks of mobile agents

    NASA Astrophysics Data System (ADS)

    Yang, Han-Xin; Wang, Wen-Xu; Xie, Yan-Bo; Lai, Ying-Cheng; Wang, Bing-Hong

    2011-01-01

    Most existing works on transportation dynamics focus on networks of a fixed structure, but networks whose nodes are mobile have become widespread, such as cell-phone networks. We introduce a model to explore the basic physics of transportation on mobile networks. Of particular interest is the dependence of the throughput on the speed of agent movement and the communication range. Our computations reveal a hierarchical dependence for the former, while an algebraic power law is found between the throughput and the communication range with the exponent determined by the speed. We develop a physical theory based on the Fokker-Planck equation to explain these phenomena. Our findings provide insights into complex transportation dynamics arising commonly in natural and engineering systems.

  9. Innovation Agents: Vocational Education and Training Skills and Innovation in Australian Industries and Firms. Volume I

    ERIC Educational Resources Information Center

    Toner, Phillip; Marceau, Jane; Hall, Richard; Considine, Gillian

    2004-01-01

    Australia's competitive success with innovation-based products and services is an influential factor to its long-term prosperity. This study examines the role of vocational education and training (VET) and occupations in innovative industries and firms. The authors find VET is vital to developing knowledge and practical skills across a broad range…

  10. Examining the articulation of innovativeness in co-creative firms: a neural network approach

    NASA Astrophysics Data System (ADS)

    di Tollo, Giacomo; Tanev, Stoyan

    2010-10-01

    Value co-creation is an emerging marketing and innovation paradigm describing a broader opening of the firm to its customers by providing them with the opportunity to become active participants in the design and development of personalized products, services and experiences. The aim of the present contribution is to provide preliminary results from a research project focusing on the relationship between value co-creation and the perception of innovation in technology-driven firms. The data was collected in a previous study using web search techniques and factor analysis to identify the key co-creation components and the frequency of firms' online comments about their new products, processes and services. The present work focuses on using an Artificial Neural Network (ANN) approach to understand if the extent of value co-creation activities can be thought of as an indicator of the perception of innovation. The preliminary simulation results indicate the existence of such relationship. The ANN approach does not suggest a specific model but the relationship that was found out between the forecasted values of the perception of innovation and its actual values clearly points in this direction.

  11. Examining the articulation of innovativeness in co-creative firms: a neural network approach

    NASA Astrophysics Data System (ADS)

    di Tollo, Giacomo; Tanev, Stoyan

    2011-03-01

    Value co-creation is an emerging marketing and innovation paradigm describing a broader opening of the firm to its customers by providing them with the opportunity to become active participants in the design and development of personalized products, services and experiences. The aim of the present contribution is to provide preliminary results from a research project focusing on the relationship between value co-creation and the perception of innovation in technology-driven firms. The data was collected in a previous study using web search techniques and factor analysis to identify the key co-creation components and the frequency of firms' online comments about their new products, processes and services. The present work focuses on using an Artificial Neural Network (ANN) approach to understand if the extent of value co-creation activities can be thought of as an indicator of the perception of innovation. The preliminary simulation results indicate the existence of such relationship. The ANN approach does not suggest a specific model but the relationship that was found out between the forecasted values of the perception of innovation and its actual values clearly points in this direction.

  12. Consensus in networks of mobile communicating agents

    NASA Astrophysics Data System (ADS)

    Baronchelli, Andrea; Díaz-Guilera, Albert

    2012-01-01

    Populations of mobile and communicating agents describe a vast array of technological and natural systems, ranging from sensor networks to animal groups. Here, we investigate how a group-level agreement may emerge in the continuously evolving network defined by the local interactions of the moving individuals. We adopt a general scheme of motion in two dimensions and we let the individuals interact through the minimal naming game, a prototypical scheme to investigate social consensus. We distinguish different regimes of convergence determined by the emission range of the agents and by their mobility, and we identify the corresponding scaling behaviors of the consensus time. In the same way, we rationalize also the behavior of the maximum memory used during the convergence process, which determines the minimum cognitive/storage capacity needed by the individuals. Overall, we believe that the simple and general model presented in this paper can represent a helpful reference for a better understanding of the behavior of populations of mobile agents.

  13. Consensus in evolving networks of mobile agents

    NASA Astrophysics Data System (ADS)

    Baronchelli, Andrea; Díaz-Guilera, Albert

    2012-02-01

    Populations of mobile and communicating agents describe a vast array of technological and natural systems, ranging from sensor networks to animal groups. Here, we investigate how a group-level agreement may emerge in the continuously evolving networks defined by the local interactions of the moving individuals. We adopt a general scheme of motion in two dimensions and we let the individuals interact through the minimal naming game, a prototypical scheme to investigate social consensus. We distinguish different regimes of convergence determined by the emission range of the agents and by their mobility, and we identify the corresponding scaling behaviors of the consensus time. In the same way, we rationalize also the behavior of the maximum memory used during the convergence process, which determines the minimum cognitive/storage capacity needed by the individuals. Overall, we believe that the simple and general model presented in this talk can represent a helpful reference for a better understanding of the behavior of populations of mobile agents.

  14. Consensus in networks of mobile communicating agents.

    PubMed

    Baronchelli, Andrea; Díaz-Guilera, Albert

    2012-01-01

    Populations of mobile and communicating agents describe a vast array of technological and natural systems, ranging from sensor networks to animal groups. Here, we investigate how a group-level agreement may emerge in the continuously evolving network defined by the local interactions of the moving individuals. We adopt a general scheme of motion in two dimensions and we let the individuals interact through the minimal naming game, a prototypical scheme to investigate social consensus. We distinguish different regimes of convergence determined by the emission range of the agents and by their mobility, and we identify the corresponding scaling behaviors of the consensus time. In the same way, we rationalize also the behavior of the maximum memory used during the convergence process, which determines the minimum cognitive/storage capacity needed by the individuals. Overall, we believe that the simple and general model presented in this paper can represent a helpful reference for a better understanding of the behavior of populations of mobile agents.

  15. Coevolutionary networks of reinforcement-learning agents.

    PubMed

    Kianercy, Ardeshir; Galstyan, Aram

    2013-07-01

    This paper presents a model of network formation in repeated games where the players adapt their strategies and network ties simultaneously using a simple reinforcement-learning scheme. It is demonstrated that the coevolutionary dynamics of such systems can be described via coupled replicator equations. We provide a comprehensive analysis for three-player two-action games, which is the minimum system size with nontrivial structural dynamics. In particular, we characterize the Nash equilibria (NE) in such games and examine the local stability of the rest points corresponding to those equilibria. We also study general n-player networks via both simulations and analytical methods and find that, in the absence of exploration, the stable equilibria consist of star motifs as the main building blocks of the network. Furthermore, in all stable equilibria the agents play pure strategies, even when the game allows mixed NE. Finally, we study the impact of exploration on learning outcomes and observe that there is a critical exploration rate above which the symmetric and uniformly connected network topology becomes stable.

  16. Coevolutionary networks of reinforcement-learning agents

    NASA Astrophysics Data System (ADS)

    Kianercy, Ardeshir; Galstyan, Aram

    2013-07-01

    This paper presents a model of network formation in repeated games where the players adapt their strategies and network ties simultaneously using a simple reinforcement-learning scheme. It is demonstrated that the coevolutionary dynamics of such systems can be described via coupled replicator equations. We provide a comprehensive analysis for three-player two-action games, which is the minimum system size with nontrivial structural dynamics. In particular, we characterize the Nash equilibria (NE) in such games and examine the local stability of the rest points corresponding to those equilibria. We also study general n-player networks via both simulations and analytical methods and find that, in the absence of exploration, the stable equilibria consist of star motifs as the main building blocks of the network. Furthermore, in all stable equilibria the agents play pure strategies, even when the game allows mixed NE. Finally, we study the impact of exploration on learning outcomes and observe that there is a critical exploration rate above which the symmetric and uniformly connected network topology becomes stable.

  17. The Evolution of ICT Markets: An Agent-Based Model on Complex Networks

    NASA Astrophysics Data System (ADS)

    Zhao, Liangjie; Wu, Bangtao; Chen, Zhong; Li, Li

    Information and communication technology (ICT) products exhibit positive network effects.The dynamic process of ICT markets evolution has two intrinsic characteristics: (1) customers are influenced by each others’ purchasing decision; (2) customers are intelligent agents with bounded rationality.Guided by complex systems theory, we construct an agent-based model and simulate on complex networks to examine how the evolution can arise from the interaction of customers, which occur when they make expectations about the future installed base of a product by the fraction of neighbors who are using the same product in his personal network.We demonstrate that network effects play an important role in the evolution of markets share, which make even an inferior product can dominate the whole market.We also find that the intensity of customers’ communication can influence whether the best initial strategy for firms is to improve product quality or expand their installed base.

  18. Cooperative Multi-Agent Systems in Mobile Ad Hoc Networks

    DTIC Science & Technology

    2006-01-01

    COOPERATIVE MULTI - AGENT SYSTEMS IN MOBILE AD HOC NETWORKS Joseph P. Macker William Chao Myriam Abramson Ian Downard Information Technology Division...are, mobile ad hoc networking (MANET) and Multi - Agent Systems (MAS). Despite their value in enabling more autonomous network system operation...2006 to 00-00-2006 4. TITLE AND SUBTITLE Cooperative Multi - Agent Systems in Mobile Ad Hoc Networks 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c

  19. Time-varying causal network of the Korean financial system based on firm-specific risk premiums

    NASA Astrophysics Data System (ADS)

    Song, Jae Wook; Ko, Bonggyun; Cho, Poongjin; Chang, Woojin

    2016-09-01

    The aim of this paper is to investigate the Korean financial system based on time-varying causal network. We discover many stylized facts by utilizing the firm-specific risk premiums for measuring the causality direction from a firm to firm. At first, we discover that the interconnectedness of causal network is affected by the outbreak of financial events; the co-movement of firm-specific risk premium is strengthened after each positive event, and vice versa. Secondly, we find that the major sector of the Korean financial system is the Depositories, and the financial reform in June-2011 achieves its purpose by weakening the power of risk-spillovers of Broker-Dealers. Thirdly, we identify that the causal network is a small-world network with scale-free topology where the power-law exponents of out-Degree and negative event are more significant than those of in-Degree and positive event. Lastly, we discuss that the current aspects of causal network are closely related to the long-term future scenario of the KOSPI Composite index where the direction and stability are significantly affected by the power of risk-spillovers and the power-law exponents of degree distributions, respectively.

  20. Multi-agent tasks scheduling system in software defined networks

    NASA Astrophysics Data System (ADS)

    Skobelev, P. O.; Granichin, O. N.; Budaev, D. S.; Laryukhin, V. B.; Mayorov, I. V.

    2014-05-01

    In this paper a multi-agent tasks scheduling system in software defined networks is considered. This system is designed for distribution simulation and tasks implementation on computational resources including network dynamic characteristics and topology.

  1. The Importance of Being an Insider: How Networks Influence the Small Firm's Engagement with Formal Training

    ERIC Educational Resources Information Center

    Bishop, Dan

    2011-01-01

    Purpose: The purpose of this paper is to examine the ways in which the small firm's external relationships influence its approach to formal training and training providers. Design/methodology/approach: A qualitative approach was adopted, involving semi-structured interviews with senior managers, in 25 small firms in South Wales. These interviews…

  2. The value of less connected agents in Boolean networks

    NASA Astrophysics Data System (ADS)

    Epstein, Daniel; Bazzan, Ana L. C.

    2013-11-01

    In multiagent systems, agents often face binary decisions where one seeks to take either the minority or the majority side. Examples are minority and congestion games in general, i.e., situations that require coordination among the agents in order to depict efficient decisions. In minority games such as the El Farol Bar Problem, previous works have shown that agents may reach appropriate levels of coordination, mostly by looking at the history of past decisions. Not many works consider any kind of structure of the social network, i.e., how agents are connected. Moreover, when structure is indeed considered, it assumes some kind of random network with a given, fixed connectivity degree. The present paper departs from the conventional approach in some ways. First, it considers more realistic network topologies, based on preferential attachments. This is especially useful in social networks. Second, the formalism of random Boolean networks is used to help agents to make decisions given their attachments (for example acquaintances). This is coupled with a reinforcement learning mechanism that allows agents to select strategies that are locally and globally efficient. Third, we use agent-based modeling and simulation, a microscopic approach, which allows us to draw conclusions about individuals and/or classes of individuals. Finally, for the sake of illustration we use two different scenarios, namely the El Farol Bar Problem and a binary route choice scenario. With this approach we target systems that adapt dynamically to changes in the environment, including other adaptive decision-makers. Our results using preferential attachments and random Boolean networks are threefold. First we show that an efficient equilibrium can be achieved, provided agents do experimentation. Second, microscopic analysis show that influential agents tend to consider few inputs in their Boolean functions. Third, we have also conducted measurements related to network clustering and centrality

  3. Using Mobile Agents and Overlay Networks to Secure Electrical Netoworks

    SciTech Connect

    Dawes, Neal A.; Prosser, Bryan J.; Fulp, Errin W.; McKinnon, Archibald D.

    2013-04-01

    ABSTRACT The use of wandering, mobile agents can provide a robust approach for managing, monitoring, and securing electrical distribution networks. However, the topological structure of electrical networks can affect system performance. For example, if the multi-agent system relies on a regular inspection rate (on average, points of interest are inspected with equal frequency), then locations that are not well connected will on average be inspected less frequently. This paper discusses creation and use of overlay networks that create a virtual grid graph can provide faster coverage and a more uniform average agent sampling rate. Using overlays agents wander a virtual neighborhood consisting of only points of interest that are interconnected in a regular fashion (each point has the same number of neighbors). Experimental results will show that an overlay can often provide better network coverage and a more uniform inspection rate, which can improve cyber security by providing a faster detection of threats

  4. Adaptivity in Agent-Based Routing for Data Networks

    NASA Technical Reports Server (NTRS)

    Wolpert, David H.; Kirshner, Sergey; Merz, Chris J.; Turner, Kagan

    2000-01-01

    Adaptivity, both of the individual agents and of the interaction structure among the agents, seems indispensable for scaling up multi-agent systems (MAS s) in noisy environments. One important consideration in designing adaptive agents is choosing their action spaces to be as amenable as possible to machine learning techniques, especially to reinforcement learning (RL) techniques. One important way to have the interaction structure connecting agents itself be adaptive is to have the intentions and/or actions of the agents be in the input spaces of the other agents, much as in Stackelberg games. We consider both kinds of adaptivity in the design of a MAS to control network packet routing. We demonstrate on the OPNET event-driven network simulator the perhaps surprising fact that simply changing the action space of the agents to be better suited to RL can result in very large improvements in their potential performance: at their best settings, our learning-amenable router agents achieve throughputs up to three and one half times better than that of the standard Bellman-Ford routing algorithm, even when the Bellman-Ford protocol traffic is maintained. We then demonstrate that much of that potential improvement can be realized by having the agents learn their settings when the agent interaction structure is itself adaptive.

  5. FIPA agent based network distributed control system

    SciTech Connect

    D. Abbott; V. Gyurjyan; G. Heyes; E. Jastrzembski; C. Timmer; E. Wolin

    2003-03-01

    A control system with the capabilities to combine heterogeneous control systems or processes into a uniform homogeneous environment is discussed. This dynamically extensible system is an example of the software system at the agent level of abstraction. This level of abstraction considers agents as atomic entities that communicate to implement the functionality of the control system. Agents' engineering aspects are addressed by adopting the domain independent software standard, formulated by FIPA. Jade core Java classes are used as a FIPA specification implementation. A special, lightweight, XML RDFS based, control oriented, ontology markup language is developed to standardize the description of the arbitrary control system data processor. Control processes, described in this language, are integrated into the global system at runtime, without actual programming. Fault tolerance and recovery issues are also addressed.

  6. Agent Collaborative Target Localization and Classification in Wireless Sensor Networks

    PubMed Central

    Wang, Xue; Bi, Dao-wei; Ding, Liang; Wang, Sheng

    2007-01-01

    Wireless sensor networks (WSNs) are autonomous networks that have been frequently deployed to collaboratively perform target localization and classification tasks. Their autonomous and collaborative features resemble the characteristics of agents. Such similarities inspire the development of heterogeneous agent architecture for WSN in this paper. The proposed agent architecture views WSN as multi-agent systems and mobile agents are employed to reduce in-network communication. According to the architecture, an energy based acoustic localization algorithm is proposed. In localization, estimate of target location is obtained by steepest descent search. The search algorithm adapts to measurement environments by dynamically adjusting its termination condition. With the agent architecture, target classification is accomplished by distributed support vector machine (SVM). Mobile agents are employed for feature extraction and distributed SVM learning to reduce communication load. Desirable learning performance is guaranteed by combining support vectors and convex hull vectors. Fusion algorithms are designed to merge SVM classification decisions made from various modalities. Real world experiments with MICAz sensor nodes are conducted for vehicle localization and classification. Experimental results show the proposed agent architecture remarkably facilitates WSN designs and algorithm implementation. The localization and classification algorithms also prove to be accurate and energy efficient.

  7. Exploring Entrepreneurial Networking: An Investigation into Patterns of Firm-Specific Behaviour

    ERIC Educational Resources Information Center

    Li, Jun; Mitra, Jay

    2006-01-01

    This paper focuses on firm behaviour within business clusters and cluster-type environments. Using survey data to distinguish cluster members by the perceived degree of participation, the authors categorize them as leading, proactive or reactive players. They then examine the clustering behaviour of each of these categories. They find that (a)…

  8. Reconfigurable networking for coordinated multi-agent sensing and communications.

    PubMed

    Sutton, Jeffrey P; Jamieson, Ian M D

    2002-12-01

    An implementation of a neurally-inspired system comprised of multiple mobile sensor-effector agents is described. Each agent has features of a complex neural network that is able to communicate and adjust its behavior depending upon a variety of parameters, including changes in the environment and the behavior of other agents. The system as a whole spatiotemporally reconfigures itself to perform coordinated behaviors not obtainable with single agents. Transient clustering of agents into functional subsystems to perform specific tasks generates a "system of systems" architecture. The interesting findings of this dynamic platform show that (a) the formation and dissolution of functional subsystems is a local phenomenon without the need for global control and (b) minimal intermittent communication among the agents can yield large-scale, coordinated, goal-driven behavior under a wide range of conditions.

  9. Traffic-driven epidemic spreading on networks of mobile agents

    NASA Astrophysics Data System (ADS)

    Yang, Han-Xin; Wang, Wen-Xu; Lai, Ying-Cheng; Wang, Bing-Hong

    2012-06-01

    The question as to how traffic or transportation processes on complex networks can shape the dynamics of epidemic spreading is of great interest for a number of areas. We study traffic-driven epidemic spreading on networks of mobile agents by incorporating two routing strategies: random and greedy. We find that for the case of infinite agent delivery capacity, increasing the moving velocity has opposite effects on the outbreak of epidemic spreading for the two routing strategies. However, expanding the communication range among agents can increase the transportation efficiency but counterintuitively suppress epidemic spreading. For finite delivery capacity, the emergence of traffic congestion can effectively inhibit epidemic spreading for both routing strategies. We provide a mean-field theory to explain the numerical findings. Our results can provide insights into devising effective strategies to suppress the spreading of harmful epidemics on time-varying networks.

  10. Multi-Agent Reinforcement Learning and Adaptive Neural Networks.

    DTIC Science & Technology

    2007-11-02

    learning method. The objective was to study the utility of reinforcement learning as an approach to complex decentralized control problems. The major...accomplishment was a detailed study of multi-agent reinforcement learning applied to a large-scale decentralized stochastic control problem. This study...included a very successful demonstration that a multi-agent reinforcement learning system using neural networks could learn high-performance

  11. An endogenous model of the credit network

    NASA Astrophysics Data System (ADS)

    He, Jianmin; Sui, Xin; Li, Shouwei

    2016-01-01

    In this paper, an endogenous credit network model of firm-bank agents is constructed. The model describes the endogenous formation of firm-firm, firm-bank and bank-bank credit relationships. By means of simulations, the model is capable of showing some obvious similarities with empirical evidence found by other scholars: the upper-tail of firm size distribution can be well fitted with a power-law; the bank size distribution can be lognormally distributed with a power-law tail; the bank in-degrees of the interbank credit network as well as the firm-bank credit network fall into two-power-law distributions.

  12. Distance Preferences Small-World Communication Topology for Agent Network

    NASA Astrophysics Data System (ADS)

    Wu, Zhengping; Wang, Renming

    In multi-agent system (MAS), the communication topology of agent network plays a very important role in its collaboration. Small-world networks are the networks with high local clustering and small average path length, and the communication networks of MAS can be analyzed within the frame of small-world topology. Yet the real multiagent communication networks are abundant and the classical WS small-world model is not suitable for all cases. In this paper, two new small-world network models are presented. One is based on random graph substrate and local nodes preference reconnection and the other is based on regular graph substrate and long-range nodes preference reconnection. The characteristic of the network parameter such as the clustering coefficients, average path length, and eigenvalue λ2 and λn of the Laplacian matrix for these two models and WS model is studied. The consensus problem that based on these three models is also studied. An example is given and the conclusions are made in the end.

  13. Router Agent Technology for Policy-Based Network Management

    NASA Technical Reports Server (NTRS)

    Chow, Edward T.; Sudhir, Gurusham; Chang, Hsin-Ping; James, Mark; Liu, Yih-Chiao J.; Chiang, Winston

    2011-01-01

    This innovation can be run as a standalone network application on any computer in a networked environment. This design can be configured to control one or more routers (one instance per router), and can also be configured to listen to a policy server over the network to receive new policies based on the policy- based network management technology. The Router Agent Technology transforms the received policies into suitable Access Control List syntax for the routers it is configured to control. It commits the newly generated access control lists to the routers and provides feedback regarding any errors that were faced. The innovation also automatically generates a time-stamped log file regarding all updates to the router it is configured to control. This technology, once installed on a local network computer and started, is autonomous because it has the capability to keep listening to new policies from the policy server, transforming those policies to router-compliant access lists, and committing those access lists to a specified interface on the specified router on the network with any error feedback regarding commitment process. The stand-alone application is named RouterAgent and is currently realized as a fully functional (version 1) implementation for the Windows operating system and for CISCO routers.

  14. Emergence of Hierarchy on a Network of Complementary Agents

    NASA Astrophysics Data System (ADS)

    Copelli, M.; Dos Santos, R. M. Zorzenon; Martins, J. S. Sá

    Complementarity is one of the main features underlying the interactions in biological and biochemical systems. Inspired by those systems we propose a model for the dynamical evolution of a system composed of agents that interact due to their complementary attributes rather than their similarities. Each agent is represented by a bit-string and has an activity associated to it; the coupling among complementary peers depends on their activity. The connectivity of the system changes in time respecting the constraint of complementarity. We observe the formation of a network of active agents whose stability depends on the rate at which activity of agents diffuses in the system. The model exhibits a nonequilibrium phase transition between the ordered phase, where a stable network is generated, and a disordered phase characterized by the absence of correlation among the agents. The ordered phase exhibits multi-modal distributions of connectivity and activity, indicating a hierarchy of interaction among different populations characterized by different degrees of activity. This model may be used to study the hierarchy observed in social organizations.

  15. Behavioral networks as a model for intelligent agents

    NASA Technical Reports Server (NTRS)

    Sliwa, Nancy E.

    1990-01-01

    On-going work at NASA Langley Research Center in the development and demonstration of a paradigm called behavioral networks as an architecture for intelligent agents is described. This work focuses on the need to identify a methodology for smoothly integrating the characteristics of low-level robotic behavior, including actuation and sensing, with intelligent activities such as planning, scheduling, and learning. This work assumes that all these needs can be met within a single methodology, and attempts to formalize this methodology in a connectionist architecture called behavioral networks. Behavioral networks are networks of task processes arranged in a task decomposition hierarchy. These processes are connected by both command/feedback data flow, and by the forward and reverse propagation of weights which measure the dynamic utility of actions and beliefs.

  16. Epidemic spreading on hierarchical geographical networks with mobile agents

    NASA Astrophysics Data System (ADS)

    Han, Xiao-Pu; Zhao, Zhi-Dan; Hadzibeganovic, Tarik; Wang, Bing-Hong

    2014-05-01

    Hierarchical geographical traffic networks are critical for our understanding of scaling laws in human trajectories. Here, we investigate the susceptible-infected epidemic process evolving on hierarchical networks in which agents randomly walk along the edges and establish contacts in network nodes. We employ a metapopulation modeling framework that allows us to explore the contagion spread patterns in relation to multi-scale mobility behaviors. A series of computer simulations revealed that a shifted power-law-like negative relationship between the peak timing of epidemics τ0 and population density, and a logarithmic positive relationship between τ0 and the network size, can both be explained by the gradual enlargement of fluctuations in the spreading process. We employ a semi-analytical method to better understand the nature of these relationships and the role of pertinent demographic factors. Additionally, we provide a quantitative discussion of the efficiency of a border screening procedure in delaying epidemic outbreaks on hierarchical networks, yielding a rather limited feasibility of this mitigation strategy but also its non-trivial dependence on population density, infector detectability, and the diversity of the susceptible region. Our results suggest that the interplay between the human spatial dynamics, network topology, and demographic factors can have important consequences for the global spreading and control of infectious diseases. These findings provide novel insights into the combined effects of human mobility and the organization of geographical networks on spreading processes, with important implications for both epidemiological research and health policy.

  17. A Multi-Agent System Architecture for Sensor Networks

    PubMed Central

    Fuentes-Fernández, Rubén; Guijarro, María; Pajares, Gonzalo

    2009-01-01

    The design of the control systems for sensor networks presents important challenges. Besides the traditional problems about how to process the sensor data to obtain the target information, engineers need to consider additional aspects such as the heterogeneity and high number of sensors, and the flexibility of these networks regarding topologies and the sensors in them. Although there are partial approaches for resolving these issues, their integration relies on ad hoc solutions requiring important development efforts. In order to provide an effective approach for this integration, this paper proposes an architecture based on the multi-agent system paradigm with a clear separation of concerns. The architecture considers sensors as devices used by an upper layer of manager agents. These agents are able to communicate and negotiate services to achieve the required functionality. Activities are organized according to roles related with the different aspects to integrate, mainly sensor management, data processing, communication and adaptation to changes in the available devices and their capabilities. This organization largely isolates and decouples the data management from the changing network, while encouraging reuse of solutions. The use of the architecture is facilitated by a specific modelling language developed through metamodelling. A case study concerning a generic distributed system for fire fighting illustrates the approach and the comparison with related work. PMID:22303172

  18. A multi-agent system architecture for sensor networks.

    PubMed

    Fuentes-Fernández, Rubén; Guijarro, María; Pajares, Gonzalo

    2009-01-01

    The design of the control systems for sensor networks presents important challenges. Besides the traditional problems about how to process the sensor data to obtain the target information, engineers need to consider additional aspects such as the heterogeneity and high number of sensors, and the flexibility of these networks regarding topologies and the sensors in them. Although there are partial approaches for resolving these issues, their integration relies on ad hoc solutions requiring important development efforts. In order to provide an effective approach for this integration, this paper proposes an architecture based on the multi-agent system paradigm with a clear separation of concerns. The architecture considers sensors as devices used by an upper layer of manager agents. These agents are able to communicate and negotiate services to achieve the required functionality. Activities are organized according to roles related with the different aspects to integrate, mainly sensor management, data processing, communication and adaptation to changes in the available devices and their capabilities. This organization largely isolates and decouples the data management from the changing network, while encouraging reuse of solutions. The use of the architecture is facilitated by a specific modelling language developed through metamodelling. A case study concerning a generic distributed system for fire fighting illustrates the approach and the comparison with related work.

  19. Knowledge as a Resource--Networks Do Matter: A Study of SME Firms in Rural Illinois.

    ERIC Educational Resources Information Center

    Solymossy, Emeric

    2000-01-01

    Networks among people and businesses facilitate the capture and diffusion of technical and organizational knowledge and can be classified by type of knowledge being exchanged. Types include buyer-supplier information, technical problem-solving information, and informal community information. A survey of 141 small and medium-sized enterprises…

  20. Control of Synchronization Regimes in Networks of Mobile Interacting Agents

    NASA Astrophysics Data System (ADS)

    Perez-Diaz, Fernando; Zillmer, Ruediger; Groß, Roderich

    2017-05-01

    We investigate synchronization in a population of mobile pulse-coupled agents with a view towards implementations in swarm-robotics systems and mobile sensor networks. Previous theoretical approaches dealt with range and nearest-neighbor interactions. In the latter case, a synchronization-hindering regime for intermediate agent mobility is found. We investigate the robustness of this intermediate regime under practical scenarios. We show that synchronization in the intermediate regime can be predicted by means of a suitable metric of the phase response curve. Furthermore, we study more-realistic K -nearest-neighbor and cone-of-vision interactions, showing that it is possible to control the extent of the synchronization-hindering region by appropriately tuning the size of the neighborhood. To assess the effect of noise, we analyze the propagation of perturbations over the network and draw an analogy between the response in the hindering regime and stable chaos. Our findings reveal the conditions for the control of clock or activity synchronization of agents with intermediate mobility. In addition, the emergence of the intermediate regime is validated experimentally using a swarm of physical robots interacting with cone-of-vision interactions.

  1. A Network Analysis of Countries’ Export Flows: Firm Grounds for the Building Blocks of the Economy

    PubMed Central

    Caldarelli, Guido; Cristelli, Matthieu; Gabrielli, Andrea; Pietronero, Luciano; Scala, Antonio; Tacchella, Andrea

    2012-01-01

    In this paper we analyze the bipartite network of countries and products from UN data on country production. We define the country-country and product-product projected networks and introduce a novel method of filtering information based on elements’ similarity. As a result we find that country clustering reveals unexpected socio-geographic links among the most competing countries. On the same footings the products clustering can be efficiently used for a bottom-up classification of produced goods. Furthermore we mathematically reformulate the “reflections method” introduced by Hidalgo and Hausmann as a fixpoint problem; such formulation highlights some conceptual weaknesses of the approach. To overcome such an issue, we introduce an alternative methodology (based on biased Markov chains) that allows to rank countries in a conceptually consistent way. Our analysis uncovers a strong non-linear interaction between the diversification of a country and the ubiquity of its products, thus suggesting the possible need of moving towards more efficient and direct non-linear fixpoint algorithms to rank countries and products in the global market. PMID:23094044

  2. Cooperation in networked populations of selfish adaptive agents: Sensitivity to network structure

    NASA Astrophysics Data System (ADS)

    Gulyás, László

    2007-05-01

    This paper investigates the adaptation of cooperating strategies in an iterated prisoner's dilemma (IPD) game with individually learning agents, subject to the structure of the interaction network. In particular, we study how cooperation or defection comes to dominate the population on Watts-Strogatz networks, under varying average path lengths. Our results are in good agreement with previous works on discrete choice dynamics on networks, but are in stark contrast with results from the evolution of cooperation literature. We argue that the latter is because the different adaptation method used (i.e., adaptive learning instead of ‘evolutionary’ strategy switching).

  3. Using Swarming Agents for Scalable Security in Large Network Environments

    SciTech Connect

    Crouse, Michael; White, Jacob L.; Fulp, Errin W.; Berenhaut, Kenneth S.; Fink, Glenn A.; Haack, Jereme N.

    2011-09-23

    The difficulty of securing computer infrastructures increases as they grow in size and complexity. Network-based security solutions such as IDS and firewalls cannot scale because of exponentially increasing computational costs inherent in detecting the rapidly growing number of threat signatures. Hostbased solutions like virus scanners and IDS suffer similar issues, and these are compounded when enterprises try to monitor these in a centralized manner. Swarm-based autonomous agent systems like digital ants and artificial immune systems can provide a scalable security solution for large network environments. The digital ants approach offers a biologically inspired design where each ant in the virtual colony can detect atoms of evidence that may help identify a possible threat. By assembling the atomic evidences from different ant types the colony may detect the threat. This decentralized approach can require, on average, fewer computational resources than traditional centralized solutions; however there are limits to its scalability. This paper describes how dividing a large infrastructure into smaller managed enclaves allows the digital ant framework to effectively operate in larger environments. Experimental results will show that using smaller enclaves allows for more consistent distribution of agents and results in faster response times.

  4. A Novel Network Attack Audit System based on Multi-Agent Technology

    NASA Astrophysics Data System (ADS)

    Jianping, Wang; Min, Chen; Xianwen, Wu

    A network attack audit system which includes network attack audit Agent, host audit Agent and management control center audit Agent is proposed. And the improved multi-agent technology is carried out in the network attack audit Agent which has achieved satisfactory audit results. The audit system in terms of network attack is just in-depth, and with the function improvement of network attack audit Agent, different attack will be better analyzed and audit. In addition, the management control center Agent should manage and analyze audit results from AA (or HA) and audit data on time. And the history files of network packets and host log data should also be audit to find deeper violations that cannot be found in real time.

  5. Network Interventions on Physical Activity in an Afterschool Program: An Agent-Based Social Network Study

    PubMed Central

    Zhang, Jun; Shoham, David A.; Tesdahl, Eric

    2015-01-01

    Objectives. We studied simulated interventions that leveraged social networks to increase physical activity in children. Methods. We studied a real-world social network of 81 children (average age = 7.96 years) who lived in low socioeconomic status neighborhoods, and attended public schools and 1 of 2 structured afterschool programs. The sample was ethnically diverse, and 44% were overweight or obese. We used social network analysis and agent-based modeling simulations to test whether implementing a network intervention would increase children’s physical activity. We tested 3 intervention strategies. Results. The intervention that targeted opinion leaders was effective in increasing the average level of physical activity across the entire network. However, the intervention that targeted the most sedentary children was the best at increasing their physical activity levels. Conclusions. Which network intervention to implement depends on whether the goal is to shift the entire distribution of physical activity or to influence those most adversely affected by low physical activity. Agent-based modeling could be an important complement to traditional project planning tools, analogous to sample size and power analyses, to help researchers design more effective interventions for increasing children’s physical activity. PMID:25689202

  6. Network interventions on physical activity in an afterschool program: an agent-based social network study.

    PubMed

    Zhang, Jun; Shoham, David A; Tesdahl, Eric; Gesell, Sabina B

    2015-04-01

    We studied simulated interventions that leveraged social networks to increase physical activity in children. We studied a real-world social network of 81 children (average age = 7.96 years) who lived in low socioeconomic status neighborhoods, and attended public schools and 1 of 2 structured afterschool programs. The sample was ethnically diverse, and 44% were overweight or obese. We used social network analysis and agent-based modeling simulations to test whether implementing a network intervention would increase children's physical activity. We tested 3 intervention strategies. The intervention that targeted opinion leaders was effective in increasing the average level of physical activity across the entire network. However, the intervention that targeted the most sedentary children was the best at increasing their physical activity levels. Which network intervention to implement depends on whether the goal is to shift the entire distribution of physical activity or to influence those most adversely affected by low physical activity. Agent-based modeling could be an important complement to traditional project planning tools, analogous to sample size and power analyses, to help researchers design more effective interventions for increasing children's physical activity.

  7. Epidemic spreading on dual-structure networks with mobile agents

    NASA Astrophysics Data System (ADS)

    Yao, Yiyang; Zhou, Yinzuo

    2017-02-01

    The rapid development of modern society continually transforms the social structure which leads to an increasingly distinct dual structure of higher population density in urban areas and lower density in rural areas. Such structure may induce distinctive spreading behavior of epidemics which does not happen in a single type structure. In this paper, we study the epidemic spreading of mobile agents on dual structure networks based on SIRS model. First, beyond the well known epidemic threshold for generic epidemic model that when the infection rate is below the threshold a pertinent infectious disease will die out, we find the other epidemic threshold which appears when the infection rate of a disease is relatively high. This feature of two thresholds for the SIRS model may lead to the elimination of infectious disease when social network has either high population density or low population density. Interestingly, however, we find that when a high density area is connected to a low density may cause persistent spreading of the infectious disease, even though the same disease will die out when it spreads in each single area. This phenomenon indicates the critical role of the connection between the two areas which could radically change the behavior of spreading dynamics. Our findings, therefore, provide new understanding of epidemiology pertinent to the characteristic modern social structure and have potential to develop controlling strategies accordingly.

  8. Identification chemical agent simulants by remote infrared spectra with improved artificial neural network

    NASA Astrophysics Data System (ADS)

    Dong, Xiao-qiang; Guo, Teng-xiao; Yan, Yu-Ting; Wang, Ji; Zhang, Xu; Li, Jun-ming

    2016-03-01

    Remote infrared sensing is a good approach to detect Chemical agents which can prevent operator being poisoned. The pattern recognition algorithms such as artificial neural network are the core of the chemical agent spectra identification subsystem. This paper presents a modified artificial neural network that can effectively train and identify chemical agent remote sensing spectra. The C++ language was used to program the identification software. Then many remote sensing spectra DMMP as chemical agent simulants were used to train the artificial neural network. The results show that the adaptive momentum and adaptive learning rate accelerate the artificial neural network convergence, cross-examination avoids neural network over-fitting, and the modified artificial neural network can be used to identify chemical agents remote sensing spectra perfectly.

  9. Research of negotiation in network trade system based on multi-agent

    NASA Astrophysics Data System (ADS)

    Cai, Jun; Wang, Guozheng; Wu, Haiyan

    2009-07-01

    A construction and implementation technology of network trade based on multi-agent is described in this paper. First, we researched the technology of multi-agent, then we discussed the consumer's behaviors and the negotiation between purchaser and bargainer which emerges in the traditional business mode and analysed the key technology to implement the network trade system. Finally, we implement the system.

  10. Active defense scheme against DDoS based on mobile agent and network control in network confrontation

    NASA Astrophysics Data System (ADS)

    Luo, Rong; Li, Junshan; Ye, Xia; Wang, Rui

    2013-03-01

    In order to effective defend DDoS attacks in network confrontation, an active defense scheme against DDoS is built based on Mobile Agent and network control. A distributed collaborative active defense model is constructed by using mobile agent technology and encapsulating a variety of DDoS defense techniques. Meanwhile the network control theory is applied to establish a network confrontation's control model for DDoS to control the active defense process. It provides a new idea to solve the DDoS problem.

  11. Resilient distributed control in the presence of misbehaving agents in networked control systems.

    PubMed

    Zeng, Wente; Chow, Mo-Yuen

    2014-11-01

    In this paper, we study the problem of reaching a consensus among all the agents in the networked control systems (NCS) in the presence of misbehaving agents. A reputation-based resilient distributed control algorithm is first proposed for the leader-follower consensus network. The proposed algorithm embeds a resilience mechanism that includes four phases (detection, mitigation, identification, and update), into the control process in a distributed manner. At each phase, every agent only uses local and one-hop neighbors' information to identify and isolate the misbehaving agents, and even compensate their effect on the system. We then extend the proposed algorithm to the leaderless consensus network by introducing and adding two recovery schemes (rollback and excitation recovery) into the current framework to guarantee the accurate convergence of the well-behaving agents in NCS. The effectiveness of the proposed method is demonstrated through case studies in multirobot formation control and wireless sensor networks.

  12. Research of Network Security Situational Assessment Quantization Based on Mobile Agent

    NASA Astrophysics Data System (ADS)

    Xiaorong, Cheng; Su, Lang; Mingxuan, Li

    As the security situational assessment widely applying to the computer network field, scholars have designed and implemented a large number of network security situational assessment methods. However, most works are based on local area network and single host, which is hardly to meet the demand of large-scale network security assessment. In this paper, we based on quantitative hierarchical network security situational assessment model, introduced the mobile agent technology, designed the distributed computing for large-scale network and evaluated the whole network security situation for future prediction.

  13. Reducing Communication Detection and Eavesdropping using Mobile Agent Relay Networks

    DTIC Science & Technology

    2010-12-01

    to maintain a wireless network to support the users. This type of solution is often used in Mobile Ad Hoc Networking (MANET) ( Corson 1999). MANET...USA: IEEE Computer Society. Corson , S. 1999. Mobile Ad hoc Networking (MANET): Routing Protocol Performance Issues and Evaluation Considerations. RFC

  14. Secure mobile agent for telemedicine based on P2P networks.

    PubMed

    Hsu, Wen-Shin; Pan, Jiann-I

    2013-06-01

    Exploring intelligent mobile agent (MA) technology for assisting medical services or transmitting personal patient-health information in telemedicine applications has been widely investigated. Conversely, peer-to-peer (P2P) networking has become one of the most popular applications used in the Internet because of its benefits for easy-to-manage resources and because it balances workloads. Therefore, constructing an agent-based telemedicine platform based on P2P networking architecture is necessary. The main purpose of this paper is to construct a safe agent-based telemedicine that based on P2P networking architecture. Two themes are addressed in this paper: (a) the P2P network architecture for an agent-based telemedicine service, and (b) the security mechanisms for the proposed telemedicine networking architecture. When an MA contains patient information and migrates from one host to another through the Internet, it can be attacked by other software agents or agent platforms that can illegally access patient information. The proposed P2P network architecture is based on the JXTA protocol and provides two types of telemedicine service models: the predictable service model and unpredictable service model. This architecture employs a two-layer safety mechanism for MAs (i.e., time-limited black boxes and RSA undetachable signature technologies), to provide a secure solution for agent-based telemedicine services.

  15. Cooperative Resource Pricing in Service Overlay Networks for Mobile Agents

    NASA Astrophysics Data System (ADS)

    Nakano, Tadashi; Okaie, Yutaka

    The success of peer-to-peer overlay networks depends on cooperation among participating peers. In this paper, we investigate the degree of cooperation among individual peers required to induce globally favorable properties in an overlay network. Specifically, we consider a resource pricing problem in a market-oriented overlay network where participating peers sell own resources (e.g., CPU cycles) to earn energy which represents some money or rewards in the network. In the resource pricing model presented in this paper, each peer sets the price for own resource based on the degree of cooperation; non-cooperative peers attempt to maximize their own energy gains, while cooperative peers maximize the sum of own and neighbors' energy gains. Simulation results are presented to demonstrate that the network topology is an important factor influencing the minimum degree of cooperation required to increase the network-wide global energy gain.

  16. Game Theoretic, Multi-agent Approach to Network Traffic Monitoring

    DTIC Science & Technology

    2012-01-16

    models are based on observations of effects of real attackers on our university network and their influence on the network characteristics. Using these...performed on CAMNEP, an intrusion detection system based on analysis of NetFlow data, and were performed on the university network over one month. Index...dynamics,” Center for Rationality and Interactive Decision Theory, Hebrew University , Jerusalem, Discussion Paper Series dp490, Sep. 2008. [16] J. Shamma

  17. Self Organized Multi Agent Swarms (SOMAS) for Network Security Control

    DTIC Science & Technology

    2009-03-01

    no longer adequate. Intrusion detection must look both at network traffic and host activity. Any kind of defensive system must be able to handle an...over neural networks for his prob- lem domain [89]. Given the similarity between the his work and this thesis it is 146 possible differential evolution...Table 22: Enemy Avoidance scenario network destruction experiments Metric Statistical Test EV NE NS Fisher sign 1 2 1 2 Better W or se 1 2 1 2 Better

  18. The maintenance of cooperation in multiplex networks with limited and partible resources of agents

    NASA Astrophysics Data System (ADS)

    Li, Zhaofeng; Shen, Bi; Jiang, Yichuan

    2017-02-01

    In this paper, we try to explain the maintenance of cooperation in multiplex networks with limited and partible resources of agents: defection brings larger short-term benefit and cooperative agents may become defective because of the unaffordable costs of cooperative behaviors that are performed in multiple layers simultaneously. Recent studies have identified the positive effects of multiple layers on evolutionary cooperation but generally overlook the maximum costs of agents in these synchronous games. By utilizing network effects and designing evolutionary mechanisms, cooperative behaviors become prevailing in public goods games, and agents can allocate personal resources across multiple layers. First, we generalize degree diversity into multiplex networks to improve the prospect for cooperation. Second, to prevent agents allocating all the resources into one layer, a greedy-first mechanism is proposed, in which agents prefer to add additional investments in the higher-payoff layer. It is found that greedy-first agents can perform cooperative behaviors in multiplex networks when one layer is scale-free network and degree differences between conjoint nodes increase. Our work may help to explain the emergence of cooperation in the absence of individual reputation and punishment mechanisms.

  19. Dynamic Routing and Coordination in Multi-Agent Networks

    DTIC Science & Technology

    2016-06-10

    multiple domains (robotics, autonomy, combinatorics, and network science). Our work aimed to bridge multiple scientific disciplines, including...Paper Award, American Automatic Control Council, 2011 Invited Survey, Automatica, 50th anniversary volume, 2014 Article in Inaugural Issue, IEEE...Transactions on Control of Network Systems, 2014 (acceptance rate: 11 articles out of 120 submissions) Distinguished Lecture Series in

  20. Context-Driven Decision Making in Network-Centric Operations: Agent-Based Intelligent Support

    DTIC Science & Technology

    2006-01-01

    SPIIRAS CKM Workshop (MIT, Cambridge, MA; January 24, 2006 Context-Driven Decision Making in Network-Centric Operations: Agent- Based Intelligent...Operations: Agent- Based Intelligent Support 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER 5e. TASK...Enterprise and Multi-Agent Systems (Engineering and Physical Sciences Research Council, UK, 2003-2005) Ontology- Based New Order Code Generation for

  1. The Architecture of Information Fusion System Ingreenhouse Wireless Sensor Network Based on Multi-Agent

    NASA Astrophysics Data System (ADS)

    Zhu, Wenting; Chen, Ming

    In view of current unprogressive situation of factory breeding in aquaculture, this article designed a standardized, informationized and intelligentized aquaculture system, proposed a information fusion architecture based on multi-agent in greenhouse wireless sensor network (GWSN), and researched mainly the structural characteristic of the four-classed information fusion based on distributed multi-agent and the method to construct the structure inside of every agent.

  2. Explaining Inference on a Population of Independent Agents Using Bayesian Networks

    ERIC Educational Resources Information Center

    Sutovsky, Peter

    2013-01-01

    The main goal of this research is to design, implement, and evaluate a novel explanation method, the hierarchical explanation method (HEM), for explaining Bayesian network (BN) inference when the network is modeling a population of conditionally independent agents, each of which is modeled as a subnetwork. For example, consider disease-outbreak…

  3. Explaining Inference on a Population of Independent Agents Using Bayesian Networks

    ERIC Educational Resources Information Center

    Sutovsky, Peter

    2013-01-01

    The main goal of this research is to design, implement, and evaluate a novel explanation method, the hierarchical explanation method (HEM), for explaining Bayesian network (BN) inference when the network is modeling a population of conditionally independent agents, each of which is modeled as a subnetwork. For example, consider disease-outbreak…

  4. The Nature and Implications of a Resource Network as a Support System for Linking Agents.

    ERIC Educational Resources Information Center

    Reisinger, Carol

    A resource network can serve as a strategy for personnel-multiplying by performing many activities and functions that the linking agent would otherwise have to perform; e.g., such a network can provide an organized method for identifying and collecting resources, as well surveying the kinds of resources available. The Illinois Resource and…

  5. Efficient Allocation of Resources for Defense of Spatially Distributed Networks Using Agent-Based Simulation.

    PubMed

    Kroshl, William M; Sarkani, Shahram; Mazzuchi, Thomas A

    2015-09-01

    This article presents ongoing research that focuses on efficient allocation of defense resources to minimize the damage inflicted on a spatially distributed physical network such as a pipeline, water system, or power distribution system from an attack by an active adversary, recognizing the fundamental difference between preparing for natural disasters such as hurricanes, earthquakes, or even accidental systems failures and the problem of allocating resources to defend against an opponent who is aware of, and anticipating, the defender's efforts to mitigate the threat. Our approach is to utilize a combination of integer programming and agent-based modeling to allocate the defensive resources. We conceptualize the problem as a Stackelberg "leader follower" game where the defender first places his assets to defend key areas of the network, and the attacker then seeks to inflict the maximum damage possible within the constraints of resources and network structure. The criticality of arcs in the network is estimated by a deterministic network interdiction formulation, which then informs an evolutionary agent-based simulation. The evolutionary agent-based simulation is used to determine the allocation of resources for attackers and defenders that results in evolutionary stable strategies, where actions by either side alone cannot increase its share of victories. We demonstrate these techniques on an example network, comparing the evolutionary agent-based results to a more traditional, probabilistic risk analysis (PRA) approach. Our results show that the agent-based approach results in a greater percentage of defender victories than does the PRA-based approach.

  6. Business fluctuations in a credit-network economy

    NASA Astrophysics Data System (ADS)

    Delli Gatti, Domenico; Gallegati, Mauro; Greenwald, Bruce; Russo, Alberto; Stiglitz, Joseph E.

    2006-10-01

    We model a network economy with three sectors: downstream firms, upstream firms, and banks. Agents are linked by productive and credit relationships so that the behavior of one agent influences the behavior of the others through network connections. Credit interlinkages among agents are a source of bankruptcy diffusion: in fact, failure of fulfilling debt commitments would lead to bankruptcy chains. All in all, the bankruptcy in one sector can diffuse to other sectors through linkages creating a vicious cycle and bankruptcy avalanches in the network economy. Our analysis show how the choices of credit supply by both banks and firms are interrelated. While the initial impact of monetary policy is on bank behaviour, we show the interactive play between the choices made by banks, the choices made by firms in their role as providers of credit, and the choices made by firms in their role as producers.

  7. Using an agent-based model to analyze the dynamic communication network of the immune response

    PubMed Central

    2011-01-01

    Background The immune system behaves like a complex, dynamic network with interacting elements including leukocytes, cytokines, and chemokines. While the immune system is broadly distributed, leukocytes must communicate effectively to respond to a pathological challenge. The Basic Immune Simulator 2010 contains agents representing leukocytes and tissue cells, signals representing cytokines, chemokines, and pathogens, and virtual spaces representing organ tissue, lymphoid tissue, and blood. Agents interact dynamically in the compartments in response to infection of the virtual tissue. Agent behavior is imposed by logical rules derived from the scientific literature. The model captured the agent-to-agent contact history, and from this the network topology and the interactions resulting in successful versus failed viral clearance were identified. This model served to integrate existing knowledge and allowed us to examine the immune response from a novel perspective directed at exploiting complex dynamics, ultimately for the design of therapeutic interventions. Results Analyzing the evolution of agent-agent interactions at incremental time points from identical initial conditions revealed novel features of immune communication associated with successful and failed outcomes. There were fewer contacts between agents for simulations ending in viral elimination (win) versus persistent infection (loss), due to the removal of infected agents. However, early cellular interactions preceded successful clearance of infection. Specifically, more Dendritic Agent interactions with TCell and BCell Agents, and more BCell Agent interactions with TCell Agents early in the simulation were associated with the immune win outcome. The Dendritic Agents greatly influenced the outcome, confirming them as hub agents of the immune network. In addition, unexpectedly high frequencies of Dendritic Agent-self interactions occurred in the lymphoid compartment late in the loss outcomes. Conclusions

  8. Agent-Based Framework for Personalized Service Provisioning in Converged IP Networks

    NASA Astrophysics Data System (ADS)

    Podobnik, Vedran; Matijasevic, Maja; Lovrek, Ignac; Skorin-Kapov, Lea; Desic, Sasa

    In a global multi-service and multi-provider market, the Internet Service Providers will increasingly need to differentiate in the service quality they offer and base their operation on new, consumer-centric business models. In this paper, we propose an agent-based framework for the Business-to-Consumer (B2C) electronic market, comprising the Consumer Agents, Broker Agents and Content Agents, which enable Internet consumers to select a content provider in an automated manner. We also discuss how to dynamically allocate network resources to provide end-to-end Quality of Service (QoS) for a given consumer and content provider.

  9. A multi-agent genetic algorithm for community detection in complex networks

    NASA Astrophysics Data System (ADS)

    Li, Zhangtao; Liu, Jing

    2016-05-01

    Complex networks are popularly used to represent a lot of practical systems in the domains of biology and sociology, and the structure of community is one of the most important network attributes which has received an enormous amount of attention. Community detection is the process of discovering the community structure hidden in complex networks, and modularity Q is one of the best known quality functions measuring the quality of communities of networks. In this paper, a multi-agent genetic algorithm, named as MAGA-Net, is proposed to optimize modularity value for the community detection. An agent, coded by a division of a network, represents a candidate solution. All agents live in a lattice-like environment, with each agent fixed on a lattice point. A series of operators are designed, namely split and merging based neighborhood competition operator, hybrid neighborhood crossover, adaptive mutation and self-learning operator, to increase modularity value. In the experiments, the performance of MAGA-Net is validated on both well-known real-world benchmark networks and large-scale synthetic LFR networks with 5000 nodes. The systematic comparisons with GA-Net and Meme-Net show that MAGA-Net outperforms these two algorithms, and can detect communities with high speed, accuracy and stability.

  10. The Amygdala: An Agent of Change in Adolescent Neural Networks

    PubMed Central

    Scherf, K. Suzanne; Smyth, Joshua M.; Delgado, Mauricio R.

    2013-01-01

    A unique component of adolescent development is the need to master new developmental tasks in which peer interactions become primary (for the purposes of becoming autonomous from parents, forming intimate friendships, and romantic/sexual partnerships). Previously, it has been suggested that the ability to master these tasks requires an important re-organization in the relation between perceptual, motivational, affective, and cognitive systems in a very general and broad way that is fundamentally influenced by the infusion of sex hormones during pubertal development (Scherf et al., 2012). Herein, we extend this argument to suggest that the amygdala, which is vastly connected with cortical and subcortical regions and contains sex hormone receptors, may lie at the heart of this re-organization. We propose that during adolescent development there is a shift in the attribution of relevance to existing stimuli and contexts that is mediated by the amygdala (e.g., heightened relevance of peer faces, reduced relevance of physical distance from parents). As a result, amygdala inputs to existing stable neural networks are re-weighted (increased or decreased), which destabilizes the functional interactions among regions within these networks and allows for a critical restructuring of the network functional organization. This process of network re-organization enables processing of qualitatively new kinds of social information and the emergence of novel behaviors that support mastery of adolescent-specific developmental tasks. PMID:23756154

  11. An Embedded Multi-Agent Systems Based Industrial Wireless Sensor Network.

    PubMed

    Taboun, Mohammed S; Brennan, Robert W

    2017-09-14

    With the emergence of cyber-physical systems, there has been a growing interest in network-connected devices. One of the key requirements of a cyber-physical device is the ability to sense its environment. Wireless sensor networks are a widely-accepted solution for this requirement. In this study, an embedded multi-agent systems-managed wireless sensor network is presented. A novel architecture is proposed, along with a novel wireless sensor network architecture. Active and passive wireless sensor node types are defined, along with their communication protocols, and two application-specific examples are presented. A series of three experiments is conducted to evaluate the performance of the agent-embedded wireless sensor network.

  12. An Embedded Multi-Agent Systems Based Industrial Wireless Sensor Network

    PubMed Central

    Brennan, Robert W.

    2017-01-01

    With the emergence of cyber-physical systems, there has been a growing interest in network-connected devices. One of the key requirements of a cyber-physical device is the ability to sense its environment. Wireless sensor networks are a widely-accepted solution for this requirement. In this study, an embedded multi-agent systems-managed wireless sensor network is presented. A novel architecture is proposed, along with a novel wireless sensor network architecture. Active and passive wireless sensor node types are defined, along with their communication protocols, and two application-specific examples are presented. A series of three experiments is conducted to evaluate the performance of the agent-embedded wireless sensor network. PMID:28906452

  13. Multi-agent Negotiation Mechanisms for Statistical Target Classification in Wireless Multimedia Sensor Networks

    PubMed Central

    Wang, Xue; Bi, Dao-wei; Ding, Liang; Wang, Sheng

    2007-01-01

    The recent availability of low cost and miniaturized hardware has allowed wireless sensor networks (WSNs) to retrieve audio and video data in real world applications, which has fostered the development of wireless multimedia sensor networks (WMSNs). Resource constraints and challenging multimedia data volume make development of efficient algorithms to perform in-network processing of multimedia contents imperative. This paper proposes solving problems in the domain of WMSNs from the perspective of multi-agent systems. The multi-agent framework enables flexible network configuration and efficient collaborative in-network processing. The focus is placed on target classification in WMSNs where audio information is retrieved by microphones. To deal with the uncertainties related to audio information retrieval, the statistical approaches of power spectral density estimates, principal component analysis and Gaussian process classification are employed. A multi-agent negotiation mechanism is specially developed to efficiently utilize limited resources and simultaneously enhance classification accuracy and reliability. The negotiation is composed of two phases, where an auction based approach is first exploited to allocate the classification task among the agents and then individual agent decisions are combined by the committee decision mechanism. Simulation experiments with real world data are conducted and the results show that the proposed statistical approaches and negotiation mechanism not only reduce memory and computation requirements in WMSNs but also significantly enhance classification accuracy and reliability. PMID:28903223

  14. Social network analysis and agent-based modeling in social epidemiology

    PubMed Central

    2012-01-01

    The past five years have seen a growth in the interest in systems approaches in epidemiologic research. These approaches may be particularly appropriate for social epidemiology. Social network analysis and agent-based models (ABMs) are two approaches that have been used in the epidemiologic literature. Social network analysis involves the characterization of social networks to yield inference about how network structures may influence risk exposures among those in the network. ABMs can promote population-level inference from explicitly programmed, micro-level rules in simulated populations over time and space. In this paper, we discuss the implementation of these models in social epidemiologic research, highlighting the strengths and weaknesses of each approach. Network analysis may be ideal for understanding social contagion, as well as the influences of social interaction on population health. However, network analysis requires network data, which may sacrifice generalizability, and causal inference from current network analytic methods is limited. ABMs are uniquely suited for the assessment of health determinants at multiple levels of influence that may couple with social interaction to produce population health. ABMs allow for the exploration of feedback and reciprocity between exposures and outcomes in the etiology of complex diseases. They may also provide the opportunity for counterfactual simulation. However, appropriate implementation of ABMs requires a balance between mechanistic rigor and model parsimony, and the precision of output from complex models is limited. Social network and agent-based approaches are promising in social epidemiology, but continued development of each approach is needed. PMID:22296660

  15. Research on e-commerce transaction networks using multi-agent modelling and open application programming interface

    NASA Astrophysics Data System (ADS)

    Piao, Chunhui; Han, Xufang; Wu, Harris

    2010-08-01

    We provide a formal definition of an e-commerce transaction network. Agent-based modelling is used to simulate e-commerce transaction networks. For real-world analysis, we studied the open application programming interfaces (APIs) from eBay and Taobao e-commerce websites and captured real transaction data. Pajek is used to visualise the agent relationships in the transaction network. We derived one-mode networks from the transaction network and analysed them using degree and betweenness centrality. Integrating multi-agent modelling, open APIs and social network analysis, we propose a new way to study large-scale e-commerce systems.

  16. Interaction in agent-based economics: A survey on the network approach

    NASA Astrophysics Data System (ADS)

    Bargigli, Leonardo; Tedeschi, Gabriele

    2014-04-01

    In this paper we aim to introduce the reader to some basic concepts and instruments used in a wide range of economic networks models. In particular, we adopt the theory of random networks as the main tool to describe the relationship between the organization of interaction among individuals within different components of the economy and overall aggregate behavior. The focus is on the ways in which economic agents interact and the possible consequences of their interaction on the system. We show that network models are able to introduce complex phenomena in economic systems by allowing for the endogenous evolution of networks.

  17. Emergence and scaling of synchronization in moving-agent networks with restrictive interactions

    NASA Astrophysics Data System (ADS)

    Kim, Beomseok; Do, Younghae; Lai, Ying-Cheng

    2013-10-01

    In fields such as robotics and sensor networks, synchronization among mobile and dynamic agents is a basic task. We articulate an effective strategy to achieve synchronization in dynamic networks of moving chaotic agents. Our counterintuitive idea is to restrict agents’ ability to interact with each other, which can be implemented by designating a finite number of fixed zones in the space, in which agents are allowed to interact with each other but agents outside the zones are deprived of the ability of mutual interaction. Our setting is thus different from the one used in existing works on synchronization of mobile agents where each agent is associated with an interacting zone that moves with the agent. We find, through a mathematical analysis, that an optimal interval exists in the interaction probability, where stable synchronization emerges. An inverse square-root scaling law is uncovered which relates the interval with the system size, i.e., the total number of moving agents. Extensive numerical support for physical spaces of one, two, and three dimensions is provided.

  18. A mobile-agent based wireless sensing network for structural monitoring applications

    SciTech Connect

    Taylor, Stuart G; Farinholt, Kevin M; Figueiredo, Eloi; Park, Gyuhae; Farrar, Charles R; Flynn, Eric B; Mascarenas, David L; Todd, Michael D

    2008-01-01

    A new wireless sensing network paradigm is presented for structural monitoring applications. In this approach, both power and data interrogation commands are conveyed via a mobile agent that is sent to sensor nodes to perform intended interrogations, which can alleviate several limitations of the traditional sensing networks. Furthermore, the mobile agent provides computational power to make near real-time assessments on the structural conditions. This paper will discuss such prototype systems, which are used to interrogate impedance-based sensors for structural health monitoring applications. Our wireless sensor node is specifically designed to accept various energy sources, including wireless energy transmission, and to be wirelessly triggered on an as-needed basis by the mobile agent or other sensor nodes. The capabilities of this proposed sensing network paradigm are demonstrated in the laboratory and the field.

  19. An Intelligent Control for the Distributed Flexible Network Photovoltaic System using Autonomous Control and Agent

    NASA Astrophysics Data System (ADS)

    Park, Sangsoo; Miura, Yushi; Ise, Toshifumi

    This paper proposes an intelligent control for the distributed flexible network photovoltaic system using autonomous control and agent. The distributed flexible network photovoltaic system is composed of a secondary battery bank and a number of subsystems which have a solar array, a dc/dc converter and a load. The control mode of dc/dc converter can be selected based on local information by autonomous control. However, if only autonomous control using local information is applied, there are some problems associated with several cases such as voltage drop on long power lines. To overcome these problems, the authors propose introducing agents to improve control characteristics. The autonomous control with agents is called as intelligent control in this paper. The intelligent control scheme that employs the communication between agents is applied for the model system and proved with simulation using PSCAD/EMTDC.

  20. Patterns of cooperation: fairness and coordination in networks of interacting agents

    NASA Astrophysics Data System (ADS)

    Do, Anne-Ly; Rudolf, Lars; Gross, Thilo

    2010-06-01

    We study the self-assembly of a complex network of collaborations among self-interested agents. The agents can maintain different levels of cooperation with different partners. Further, they continuously, selectively and independently adapt the amount of resources allocated to each of their collaborations in order to maximize the obtained payoff. We show analytically that the system approaches a state in which the agents make identical investments, and links produce identical benefits. Despite this high degree of social coordination, some agents manage to secure privileged topological positions in the network, enabling them to extract high payoffs. Our analytical investigations provide a rationale for the emergence of unidirectional non-reciprocal collaborations and different responses to the withdrawal of a partner from an interaction that have been reported in the psychological literature.

  1. Social adaptation in multi-agent model of linguistic categorization is affected by network information flow.

    PubMed

    Zubek, Julian; Denkiewicz, Michał; Barański, Juliusz; Wróblewski, Przemysław; Rączaszek-Leonardi, Joanna; Plewczynski, Dariusz

    2017-01-01

    This paper explores how information flow properties of a network affect the formation of categories shared between individuals, who are communicating through that network. Our work is based on the established multi-agent model of the emergence of linguistic categories grounded in external environment. We study how network information propagation efficiency and the direction of information flow affect categorization by performing simulations with idealized network topologies optimizing certain network centrality measures. We measure dynamic social adaptation when either network topology or environment is subject to change during the experiment, and the system has to adapt to new conditions. We find that both decentralized network topology efficient in information propagation and the presence of central authority (information flow from the center to peripheries) are beneficial for the formation of global agreement between agents. Systems with central authority cope well with network topology change, but are less robust in the case of environment change. These findings help to understand which network properties affect processes of social adaptation. They are important to inform the debate on the advantages and disadvantages of centralized systems.

  2. Social adaptation in multi-agent model of linguistic categorization is affected by network information flow

    PubMed Central

    Denkiewicz, Michał; Barański, Juliusz; Wróblewski, Przemysław; Rączaszek-Leonardi, Joanna; Plewczynski, Dariusz

    2017-01-01

    This paper explores how information flow properties of a network affect the formation of categories shared between individuals, who are communicating through that network. Our work is based on the established multi-agent model of the emergence of linguistic categories grounded in external environment. We study how network information propagation efficiency and the direction of information flow affect categorization by performing simulations with idealized network topologies optimizing certain network centrality measures. We measure dynamic social adaptation when either network topology or environment is subject to change during the experiment, and the system has to adapt to new conditions. We find that both decentralized network topology efficient in information propagation and the presence of central authority (information flow from the center to peripheries) are beneficial for the formation of global agreement between agents. Systems with central authority cope well with network topology change, but are less robust in the case of environment change. These findings help to understand which network properties affect processes of social adaptation. They are important to inform the debate on the advantages and disadvantages of centralized systems. PMID:28809957

  3. Finite-time consensus for leader-following multi-agent systems over switching network topologies

    NASA Astrophysics Data System (ADS)

    Sun, Feng-Lan; Zhu, Wei

    2013-11-01

    Finite-time consensus problem of the leader-following multi-agent system under switching network topologies is studied in this paper. Based on the graph theory, matrix theory, homogeneity with dilation, and LaSalle's invariance principle, the control protocol of each agent using local information is designed, and the detailed analysis of the leader-following finite-time consensus is provided. Some examples and simulation results are given to illustrate the effectiveness of the obtained theoretical results.

  4. Using Agent Base Models to Optimize Large Scale Network for Large System Inventories

    NASA Technical Reports Server (NTRS)

    Shameldin, Ramez Ahmed; Bowling, Shannon R.

    2010-01-01

    The aim of this paper is to use Agent Base Models (ABM) to optimize large scale network handling capabilities for large system inventories and to implement strategies for the purpose of reducing capital expenses. The models used in this paper either use computational algorithms or procedure implementations developed by Matlab to simulate agent based models in a principal programming language and mathematical theory using clusters, these clusters work as a high performance computational performance to run the program in parallel computational. In both cases, a model is defined as compilation of a set of structures and processes assumed to underlie the behavior of a network system.

  5. Agent-based analysis of trustworthiness in wireless sensor networks

    NASA Astrophysics Data System (ADS)

    Fernandes, Ronald; Li, Biyan; Vadakkeveedu, Kalyan; Verma, Ajay; Gustafson, Paul; Hwang, Jong

    2012-06-01

    Information assurance is a critical component of any organization's data network. Trustworthiness of the sensor data, especially in the case of wireless sensor networks (WSNs), is an important metric for any application that requires situational awareness. In a WSN, information packets are typically not encrypted and the nodes themselves could be located in the open, leaving them susceptible to tampering and physical degradation. In order to develop a method to assess trustworthiness in WSNs, we have utilized statistical trustworthiness metrics and have implemented an agentbased simulation platform that can perform various trustworthiness measurement experiments for various WSN operating scenarios. Different trust metrics are used against multiple vulnerabilities to detect anomalous behavior and node failure as well as malicious attacks. The simulation platform simulates WSNs with various topologies, routing algorithms, battery and power consumption models, and various types of attacks and defense mechanisms. Additionally, we adopt information entropy based techniques to detect anomalous behavior. Finally, detection techniques are fused to provide various metrics, and various trustworthiness metrics are fused to provide aggregate trustworthiness for the purpose of situational awareness.

  6. Impact of mobility structure on optimization of small-world networks of mobile agents

    NASA Astrophysics Data System (ADS)

    Lee, Eun; Holme, Petter

    2016-06-01

    In ad hoc wireless networking, units are connected to each other rather than to a central, fixed, infrastructure. Constructing and maintaining such networks create several trade-off problems between robustness, communication speed, power consumption, etc., that bridges engineering, computer science and the physics of complex systems. In this work, we address the role of mobility patterns of the agents on the optimal tuning of a small-world type network construction method. By this method, the network is updated periodically and held static between the updates. We investigate the optimal updating times for different scenarios of the movement of agents (modeling, for example, the fat-tailed trip distances, and periodicities, of human travel). We find that these mobility patterns affect the power consumption in non-trivial ways and discuss how these effects can best be handled.

  7. Hierarchical Supervisor and Agent Routing Algorithm in LEO/MEO Double-layered Optical Satellite Network

    NASA Astrophysics Data System (ADS)

    Li, Yongjun; Zhao, Shanghong

    2016-09-01

    A novel routing algorithm (Hierarchical Supervisor and Agent Routing Algorithm, HSARA) for LEO/MEO (low earth orbit/medium earth orbit) double-layered optical satellite network is brought forward. The so-called supervisor (MEO satellite) is designed for failure recovery and network management. LEO satellites are grouped according to the virtual managed field of MEO which is different from coverage area of MEO satellite in RF satellite network. In each LEO group, one LEO satellite which has maximal persistent link with its supervisor is called the agent. A LEO group is updated when this optical inter-orbit links between agent LEO satellite and the corresponding MEO satellite supervisor cuts off. In this way, computations of topology changes and LEO group updating can be decreased. Expense of routing is integration of delay and wavelength utilization. HSARA algorithm simulations are implemented and the results are as follows: average network delay of HSARA can reduce 21 ms and 31.2 ms compared with traditional multilayered satellite routing and single-layer LEO satellite respectively; LEO/MEO double-layered optical satellite network can cover polar region which cannot be covered by single-layered LEO satellite and throughput is 1% more than that of single-layered LEO satellite averagely. Therefore, exact global coverage can be achieved with this double-layered optical satellite network.

  8. Intelligent microchip networks: an agent-on-chip synthesis framework for the design of smart and robust sensor networks

    NASA Astrophysics Data System (ADS)

    Bosse, Stefan

    2013-05-01

    Sensorial materials consisting of high-density, miniaturized, and embedded sensor networks require new robust and reliable data processing and communication approaches. Structural health monitoring is one major field of application for sensorial materials. Each sensor node provides some kind of sensor, electronics, data processing, and communication with a strong focus on microchip-level implementation to meet the goals of miniaturization and low-power energy environments, a prerequisite for autonomous behaviour and operation. Reliability requires robustness of the entire system in the presence of node, link, data processing, and communication failures. Interaction between nodes is required to manage and distribute information. One common interaction model is the mobile agent. An agent approach provides stronger autonomy than a traditional object or remote-procedure-call based approach. Agents can decide for themselves, which actions are performed, and they are capable of flexible behaviour, reacting on the environment and other agents, providing some degree of robustness. Traditionally multi-agent systems are abstract programming models which are implemented in software and executed on program controlled computer architectures. This approach does not well scale to micro-chip level and requires full equipped computers and communication structures, and the hardware architecture does not consider and reflect the requirements for agent processing and interaction. We propose and demonstrate a novel design paradigm for reliable distributed data processing systems and a synthesis methodology and framework for multi-agent systems implementable entirely on microchip-level with resource and power constrained digital logic supporting Agent-On-Chip architectures (AoC). The agent behaviour and mobility is fully integrated on the micro-chip using pipelined communicating processes implemented with finite-state machines and register-transfer logic. The agent behaviour

  9. An Agent-Based Model of Centralized Institutions, Social Network Technology, and Revolution

    PubMed Central

    Makowsky, Michael D.; Rubin, Jared

    2013-01-01

    This paper sheds light on the general mechanisms underlying large-scale social and institutional change. We employ an agent-based model to test the impact of authority centralization and social network technology on preference falsification and institutional change. We find that preference falsification is increasing with centralization and decreasing with social network range. This leads to greater cascades of preference revelation and thus more institutional change in highly centralized societies and this effect is exacerbated at greater social network ranges. An empirical analysis confirms the connections that we find between institutional centralization, social radius, preference falsification, and institutional change. PMID:24278280

  10. Self-Learning Intelligent Agents for Dynamic Traffic Routing on Transportation Networks

    NASA Astrophysics Data System (ADS)

    Sadek, Add; Basha, Nagi

    Intelligent Transportation Systems (ITS) are designed to take advantage of recent advances in communications, electronics, and Information Technology in improving the efficiency and safety of transportation systems. Among the several ITS applications is the notion of Dynamic Traffic Routing (DTR), which involves generating "optimal" routing recommendations to drivers with the aim of maximizing network utilizing. In this paper, we demonstrate the feasibility of using a self-learning intelligent agent to solve the DTR problem to achieve traffic user equilibrium in a transportation network. The core idea is to deploy an agent to a simulation model of a highway. The agent then learns by itself by interacting with the simulation model. Once the agent reaches a satisfactory level of performance, it can then be deployed to the real-world, where it would continue to learn how to refine its control policies over time. To test this concept in this paper, the Cell Transmission Model (CTM) developed by Carlos Daganzo of the University of California at Berkeley is used to simulate a simple highway with two main alternative routes. With the model developed, a Reinforcement Learning Agent (RLA) is developed to learn how to best dynamically route traffic, so as to maximize the utilization of existing capacity. Preliminary results obtained from our experiments are promising. RL, being an adaptive online learning technique, appears to have a great potential for controlling a stochastic dynamic systems such as a transportation system. Furthermore, the approach is highly scalable and applicable to a variety of networks and roadways.

  11. Studies of Opinion Stability for Small Dynamic Networks with Opportunistic Agents

    NASA Astrophysics Data System (ADS)

    Sobkowicz, Pawel

    There are numerous examples of societies with extremely stable mix of contrasting opinions. We argue that this stability is a result of an interplay between society network topology adjustment and opinion changing processes. To support this position we present a computer model of opinion formation based on some novel assumptions, designed to bring the model closer to social reality. In our model, the agents, in addition to changing their opinions due to influence of the rest of society and external propaganda, have the ability to modify their social network, forming links with agents sharing the same opinions and cutting the links with those they disagree with. To improve the model further we divide the agents into "fanatics" and "opportunists," depending on how easy it is to change their opinions. The simulations show significant differences compared to traditional models, where network links are static. In particular, for the dynamical model where inter-agent links are adjustable, the final network structure and opinion distribution is shown to resemble real world observations, such as social structures and persistence of minority groups even when most of the society is against them and the propaganda is strong.

  12. Cooperative Interface Agents for Networked Command, Control, and Communications: Phase II

    DTIC Science & Technology

    2006-04-01

    information to the edge of the force network. To the warfighter, this means the empowerment that more information provides, but also the burden of making...Interaction [ HCI -97], Atlanta, GA. Maes, P. (1994). Agents that Reduce Work and Information Overload. Communication of the ACM, 37(7), 30-40. Maes, P

  13. Interaction and Communication of Agents in Networks and Language Complexity Estimates

    NASA Technical Reports Server (NTRS)

    Smid, Jan; Obitko, Marek; Fisher, David; Truszkowski, Walt

    2004-01-01

    Knowledge acquisition and sharing are arguably the most critical activities of communicating agents. We report about our on-going project featuring knowledge acquisition and sharing among communicating agents embedded in a network. The applications we target range from hardware robots to virtual entities such as internet agents. Agent experiments can be simulated using a convenient simulation language. We analyzed the complexity of communicating agent simulations using Java and Easel. Scenarios we have studied are listed below. The communication among agents can range from declarative queries to sub-natural language queries. 1) A set of agents monitoring an object are asked to build activity profiles based on exchanging elementary observations; 2) A set of car drivers form a line, where every car is following its predecessor. An unsafe distance cm create a strong wave in the line. Individual agents are asked to incorporate and apply directions how to avoid the wave. 3) A set of micro-vehicles form a grid and are asked to propagate information and concepts to a central server.

  14. Establishment and Maintenance of a Knowledge Network by Means of Agents and Implicit Data

    NASA Astrophysics Data System (ADS)

    Moreno–Llorena, Jaime; Alamán, Xavier; Cobos, Ruth

    Semantic KnowCat (SKC) is a groupware system prototype for Knowledge Management on the Web by means of semantic information without supervision. The main aim of SKC is to select the knowledge contained in the system by paying attention to its use. This paper presents the SKC Network Module (NM), which is in charge of discovering other instances of the system on the Internet and establishing contact with them to create a knowledge network on the Web. In order to do this, each instance of the system is represented by a software agent, which is in charge of interacting with Web search engines and collaborating with the agents that represent other system instances, thereby using data mining techniques. As a result, SKC manages to build and maintain a network node to share knowledge.

  15. Effects of competition and cooperation interaction between agents on networks in the presence of a market capacity

    NASA Astrophysics Data System (ADS)

    Sonubi, A.; Arcagni, A.; Stefani, S.; Ausloos, M.

    2016-08-01

    A network effect is introduced taking into account competition, cooperation, and mixed-type interaction among agents along a generalized Verhulst-Lotka-Volterra model. It is also argued that the presence of a market capacity undoubtedly enforces a definite limit on the agent's size growth. The state stability of triadic agents, i.e., the most basic network plaquette, is investigated analytically for possible scenarios, through a fixed-point analysis. It is discovered that: (i) market demand is only satisfied for full competition when one agent monopolizes the market; (ii) growth of agent size is encouraged in full cooperation; (iii) collaboration among agents to compete against one single agent may result in the disappearance of this single agent out of the market; and (iv) cooperating with two rivals may become a growth strategy for an intelligent agent.

  16. Effects of competition and cooperation interaction between agents on networks in the presence of a market capacity.

    PubMed

    Sonubi, A; Arcagni, A; Stefani, S; Ausloos, M

    2016-08-01

    A network effect is introduced taking into account competition, cooperation, and mixed-type interaction among agents along a generalized Verhulst-Lotka-Volterra model. It is also argued that the presence of a market capacity undoubtedly enforces a definite limit on the agent's size growth. The state stability of triadic agents, i.e., the most basic network plaquette, is investigated analytically for possible scenarios, through a fixed-point analysis. It is discovered that: (i) market demand is only satisfied for full competition when one agent monopolizes the market; (ii) growth of agent size is encouraged in full cooperation; (iii) collaboration among agents to compete against one single agent may result in the disappearance of this single agent out of the market; and (iv) cooperating with two rivals may become a growth strategy for an intelligent agent.

  17. Nerve agent detection using networks of single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Novak, J. P.; Snow, E. S.; Houser, E. J.; Park, D.; Stepnowski, J. L.; McGill, R. A.

    2003-11-01

    We report the use of carbon nanotubes as a sensor for chemical nerve agents. Thin-film transistors constructed from random networks of single-walled carbon nanotubes were used to detect dimethyl methylphosphonate (DMMP), a simulant for the nerve agent sarin. These sensors are reversible and capable of detecting DMMP at sub-ppb concentration levels, and they are intrinsically selective against interferent signals from hydrocarbon vapors and humidity. We provide additional chemical specificity by the use of filters coated with chemoselective polymer films. These results indicate that the electronic detection of sub-ppb concentrations of nerve agents and potentially other chemical warfare agents is possible with simple-to-fabricate carbon nanotube devices.

  18. Neural network analysis of terahertz spectra of explosives and bio-agents

    NASA Astrophysics Data System (ADS)

    Oliveira, Felipe; Barat, Robert; Shulkin, Brian; Federici, John F.; Gary, Dale; Zimdars, David A.

    2003-08-01

    A proposed, non-invasive, means to detect and characterize concealed biological and explosive agents in near real-time with a wide field-of-view uses spatial imaging of their characteristic transmission or reflectivity wavelength spectrum in the Terahertz (THz) electro-magnetic range (0.1-3 THz). Neural network analyses of the THz spectra and images will provide the specificity of agent detection and reduce the frequency of false alarms. Artificial neural networks are mathematical devices for modeling complex, non-linear functionalities. The key to a successful neural network is adequate training with known input-output data. Important challenges in the research include identification of the preferred network structure (e.g. multi-layer perceptron), number of hidden nodes, training algorithm (e.g. back propagation), and determination of what type of THz spectral image pre-processing is needed prior to application of the network. Detector array images containing both spectral and spatial information are analyzed with the aid of the Neurosolutions(TM) commercial neural network software package.

  19. Shared vision promotes family firm performance

    PubMed Central

    Neff, John E.

    2015-01-01

    A clear picture of the influential drivers of private family firm performance has proven to be an elusive target. The unique characteristics of private family owned firms necessitate a broader, non-financial approach to reveal firm performance drivers. This research study sought to specify and evaluate the themes that distinguish successful family firms from less successful family firms. In addition, this study explored the possibility that these themes collectively form an effective organizational culture that improves longer-term firm performance. At an organizational level of analysis, research findings identified four significant variables: Shared Vision (PNS), Role Clarity (RCL), Confidence in Management (CON), and Professional Networking (OLN) that positively impacted family firm financial performance. Shared Vision exhibited the strongest positive influence among the significant factors. In addition, Family Functionality (APGAR), the functional integrity of the family itself, exhibited a significant supporting role. Taken together, the variables collectively represent an effective family business culture (EFBC) that positively impacted the long-term financial sustainability of family owned firms. The index of effective family business culture also exhibited potential as a predictive non-financial model of family firm performance. PMID:26042075

  20. Shared vision promotes family firm performance.

    PubMed

    Neff, John E

    2015-01-01

    A clear picture of the influential drivers of private family firm performance has proven to be an elusive target. The unique characteristics of private family owned firms necessitate a broader, non-financial approach to reveal firm performance drivers. This research study sought to specify and evaluate the themes that distinguish successful family firms from less successful family firms. In addition, this study explored the possibility that these themes collectively form an effective organizational culture that improves longer-term firm performance. At an organizational level of analysis, research findings identified four significant variables: Shared Vision (PNS), Role Clarity (RCL), Confidence in Management (CON), and Professional Networking (OLN) that positively impacted family firm financial performance. Shared Vision exhibited the strongest positive influence among the significant factors. In addition, Family Functionality (APGAR), the functional integrity of the family itself, exhibited a significant supporting role. Taken together, the variables collectively represent an effective family business culture (EFBC) that positively impacted the long-term financial sustainability of family owned firms. The index of effective family business culture also exhibited potential as a predictive non-financial model of family firm performance.

  1. Automation of multi-agent control for complex dynamic systems in heterogeneous computational network

    NASA Astrophysics Data System (ADS)

    Oparin, Gennady; Feoktistov, Alexander; Bogdanova, Vera; Sidorov, Ivan

    2017-01-01

    The rapid progress of high-performance computing entails new challenges related to solving large scientific problems for various subject domains in a heterogeneous distributed computing environment (e.g., a network, Grid system, or Cloud infrastructure). The specialists in the field of parallel and distributed computing give the special attention to a scalability of applications for problem solving. An effective management of the scalable application in the heterogeneous distributed computing environment is still a non-trivial issue. Control systems that operate in networks, especially relate to this issue. We propose a new approach to the multi-agent management for the scalable applications in the heterogeneous computational network. The fundamentals of our approach are the integrated use of conceptual programming, simulation modeling, network monitoring, multi-agent management, and service-oriented programming. We developed a special framework for an automation of the problem solving. Advantages of the proposed approach are demonstrated on the parametric synthesis example of the static linear regulator for complex dynamic systems. Benefits of the scalable application for solving this problem include automation of the multi-agent control for the systems in a parallel mode with various degrees of its detailed elaboration.

  2. A New HIV Prevention Network Approach: Sociometric Peer Change Agent Selection

    PubMed Central

    Schneider, John A.; Zhou, A. Ning; Laumann, Edward O.

    2014-01-01

    Internationally, the Peer Change Agent (PCA) model is the most frequently used conceptual framework for HIV prevention. Change agents themselves can be more important than the messages they convey. PCA selection is operationalized via heterogeneous methods based upon individual-level attributes. A sociometric position selection strategy, however, could increase peer influence potency and halt transmission at key network locations. In this study, we selected candidate PCAs based upon relative sociometric bridging and centrality scores and assessed their attributes in comparison to one another and to existing peer educators. We focused upon an emerging HIV epidemic among men who have sex with men in Southern India in 2011. PCAs selected based on their bridging score were more likely to be innovators when compared to other centrally-located PCAs, to PCAs located on the periphery, and to existing peer educators. We also found that sociodemographic attributes and risk behaviors were similar across all candidate PCAs, but risk behaviors of existing peer educators differed. Existing peer educators were more likely to engage in higher risk behavior such as receiving money for sex when compared to sociometrically selected peer changes agents. These existing peer educators were also more likely to exhibit leadership qualities within the overall network; they were, however, just as likely as other non-trained candidate peer change agents to report important HIV intravention behavior (encouraging condoms within their network). The importance of identifying bridges who may be able to diffuse innovation more effectively within high risk HIV networks is especially critical given recent efficacy data from novel HIV prevention interventions such as pre-exposure prophylaxis. Moreover, while existing peer educators were more likely to be leaders in our analysis, using peer educators with high risk behavior may have limited utility in enacting behavior change among sex worker peers or

  3. Multi-agent-based bio-network for systems biology: protein-protein interaction network as an example.

    PubMed

    Ren, Li-Hong; Ding, Yong-Sheng; Shen, Yi-Zhen; Zhang, Xiang-Feng

    2008-10-01

    Recently, a collective effort from multiple research areas has been made to understand biological systems at the system level. This research requires the ability to simulate particular biological systems as cells, organs, organisms, and communities. In this paper, a novel bio-network simulation platform is proposed for system biology studies by combining agent approaches. We consider a biological system as a set of active computational components interacting with each other and with an external environment. Then, we propose a bio-network platform for simulating the behaviors of biological systems and modelling them in terms of bio-entities and society-entities. As a demonstration, we discuss how a protein-protein interaction (PPI) network can be seen as a society of autonomous interactive components. From interactions among small PPI networks, a large PPI network can emerge that has a remarkable ability to accomplish a complex function or task. We also simulate the evolution of the PPI networks by using the bio-operators of the bio-entities. Based on the proposed approach, various simulators with different functions can be embedded in the simulation platform, and further research can be done from design to development, including complexity validation of the biological system.

  4. Agent-based approach for generation of a money-centered star network

    NASA Astrophysics Data System (ADS)

    Yang, Jae-Suk; Kwon, Okyu; Jung, Woo-Sung; Kim, In-mook

    2008-09-01

    The history of trade is a progression from a pure barter system. A medium of exchange emerges autonomously in the market, a position currently occupied by money. We investigate an agent-based computational economics model consisting of interacting agents considering distinguishable properties of commodities which represent salability. We also analyze the properties of the commodity network using a spanning tree. We find that the “storage fee” is more crucial than “demand” in determining which commodity is used as a medium of exchange.

  5. Group consensus of multi-agent systems in directed networks with noises and time delays

    NASA Astrophysics Data System (ADS)

    Shang, Yilun

    2015-10-01

    In this paper, group consensus problems in fixed directed networks of dynamic agents are investigated. Group consensus means that the agents in each group share a consistent value while there is no agreement between any two groups. Based on algebraic graph theory, sufficient conditions guaranteeing group consensus under the proposed control protocol in the presence of random noises and communication delays are derived. The analysis uses a stability result of Mao for stochastic differential delay equations, which ensures the consensus can be achieved almost surely and exponentially fast. Numerical examples are provided to demonstrate the availability of the obtained results as well as the effect of time delay/noise intensity.

  6. Process and data fragmentation-oriented enterprise network integration with collaboration modelling and collaboration agents

    NASA Astrophysics Data System (ADS)

    Li, Qing; Wang, Ze-yuan; Cao, Zhi-chao; Du, Rui-yang; Luo, Hao

    2015-08-01

    With the process of globalisation and the development of management models and information technology, enterprise cooperation and collaboration has developed from intra-enterprise integration, outsourcing and inter-enterprise integration, and supply chain management, to virtual enterprises and enterprise networks. Some midfielder enterprises begin to serve for different supply chains. Therefore, they combine related supply chains into a complex enterprise network. The main challenges for enterprise network's integration and collaboration are business process and data fragmentation beyond organisational boundaries. This paper reviews the requirements of enterprise network's integration and collaboration, as well as the development of new information technologies. Based on service-oriented architecture (SOA), collaboration modelling and collaboration agents are introduced to solve problems of collaborative management for service convergence under the condition of process and data fragmentation. A model-driven methodology is developed to design and deploy the integrating framework. An industrial experiment is designed and implemented to illustrate the usage of developed technologies in this paper.

  7. Understanding animate agents: distinct roles for the social network and mirror system.

    PubMed

    Wheatley, Thalia; Milleville, Shawn C; Martin, Alex

    2007-06-01

    How people understand the actions of animate agents has been vigorously debated. This debate has centered on two hypotheses focused on anatomically distinct neural substrates: The mirror-system hypothesis proposes that the understanding of others is achieved via action simulation, and the social-network hypothesis proposes that such understanding is achieved via the integration of critical biological properties (e.g., faces, affect). In this study, we assessed the areas of the brain that were engaged when people interpreted and imagined moving shapes as animate or inanimate. Although observing and imagining the moving shapes engaged the mirror system, only activation of the social network was modulated by animacy.

  8. ModelforAnalyzing Human Communication Network Based onAgent-Based Simulation

    NASA Astrophysics Data System (ADS)

    Matsuyama, Shinako; Terano, Takao

    This paper discusses dynamic properties of human communications networks, which appears as a result of informationexchanges among people. We propose agent-based simulation (ABS) to examine implicit mechanisms behind the dynamics. The ABS enables us to reveal the characteristics and the differences of the networks regarding the specific communicationgroups. We perform experiments on the ABS with activity data from questionnaires survey and with virtual data which isdifferent from the activity data. We compare the difference between them and show the effectiveness of the ABS through theexperiments.

  9. Social networks of PLHA in Uganda: implications for mobilizing PLHA as agents for prevention.

    PubMed

    Green, Harold D; Atuyambe, Lynn; Ssali, Sarah; Ryan, Gery W; Wagner, Glenn J

    2011-07-01

    The objective of this study was to describe the social networks of people living with HIV/AIDS (PLHA) and explore the implications social network characteristics might have for mobilizing PLHA as prevention agents. Thirty-nine PLHA attending an HIV clinic in Kampala, Uganda provided information on themselves and on 20 network members. Based on these data, descriptive statistics for social network composition and structure were calculated. Research questions relating these network characteristics to treatment-related variables such as time since diagnosis, ART status, and time on ART were investigated. Analyses reveal that, in general, network members know the PLHA's status, are trusted, provide advice and support, and are well-connected to each other. Network features (e.g., proportion of individuals who know the PLHA's status) are related to the previously mentioned treatment variables. Findings suggest that PLHA surround themselves with a social context that enables PLHA to feel fairly protected and supported if they choose to discuss HIV and prevention. With respect to treatment, those on ART may be better prepared to act as prevention advocates.

  10. Employment Growth through Labor Flow Networks

    PubMed Central

    Guerrero, Omar A.; Axtell, Robert L.

    2013-01-01

    It is conventional in labor economics to treat all workers who are seeking new jobs as belonging to a labor pool, and all firms that have job vacancies as an employer pool, and then match workers to jobs. Here we develop a new approach to study labor and firm dynamics. By combining the emerging science of networks with newly available employment micro-data, comprehensive at the level of whole countries, we are able to broadly characterize the process through which workers move between firms. Specifically, for each firm in an economy as a node in a graph, we draw edges between firms if a worker has migrated between them, possibly with a spell of unemployment in between. An economy's overall graph of firm-worker interactions is an object we call the labor flow network (LFN). This is the first study that characterizes a LFN for an entire economy. We explore the properties of this network, including its topology, its community structure, and its relationship to economic variables. It is shown that LFNs can be useful in identifying firms with high growth potential. We relate LFNs to other notions of high performance firms. Specifically, it is shown that fewer than 10% of firms account for nearly 90% of all employment growth. We conclude with a model in which empirically-salient LFNs emerge from the interaction of heterogeneous adaptive agents in a decentralized labor market. PMID:23658682

  11. Metabolic network analysis-based identification of antimicrobial drug targets in category A bioterrorism agents.

    PubMed

    Ahn, Yong-Yeol; Lee, Deok-Sun; Burd, Henry; Blank, William; Kapatral, Vinayak

    2014-01-01

    The 2001 anthrax mail attacks in the United States demonstrated the potential threat of bioterrorism, hence driving the need to develop sophisticated treatment and diagnostic protocols to counter biological warfare. Here, by performing flux balance analyses on the fully-annotated metabolic networks of multiple, whole genome-sequenced bacterial strains, we have identified a large number of metabolic enzymes as potential drug targets for each of the three Category A-designated bioterrorism agents including Bacillus anthracis, Francisella tularensis and Yersinia pestis. Nine metabolic enzymes- belonging to the coenzyme A, folate, phosphatidyl-ethanolamine and nucleic acid pathways common to all strains across the three distinct genera were identified as targets. Antimicrobial agents against some of these enzymes are available. Thus, a combination of cross species-specific antibiotics and common antimicrobials against shared targets may represent a useful combinatorial therapeutic approach against all Category A bioterrorism agents.

  12. Metabolic Network Analysis-Based Identification of Antimicrobial Drug Targets in Category A Bioterrorism Agents

    PubMed Central

    Ahn, Yong-Yeol; Lee, Deok-Sun; Burd, Henry; Blank, William; Kapatral, Vinayak

    2014-01-01

    The 2001 anthrax mail attacks in the United States demonstrated the potential threat of bioterrorism, hence driving the need to develop sophisticated treatment and diagnostic protocols to counter biological warfare. Here, by performing flux balance analyses on the fully-annotated metabolic networks of multiple, whole genome-sequenced bacterial strains, we have identified a large number of metabolic enzymes as potential drug targets for each of the three Category A-designated bioterrorism agents including Bacillus anthracis, Francisella tularensis and Yersinia pestis. Nine metabolic enzymes- belonging to the coenzyme A, folate, phosphatidyl-ethanolamine and nucleic acid pathways common to all strains across the three distinct genera were identified as targets. Antimicrobial agents against some of these enzymes are available. Thus, a combination of cross species-specific antibiotics and common antimicrobials against shared targets may represent a useful combinatorial therapeutic approach against all Category A bioterrorism agents. PMID:24454817

  13. Agents.

    PubMed

    Chambers, David W

    2002-01-01

    Although health care is inherently an economic activity, it is inadequately described as a market process. An alternative, grounded in organizational economic theory, is to view professionals and many others as agents, contracted to advance the best interests of their principals (patients). This view untangles some of the ethical conflicts in dentistry. It also helps identify major controllable costs in dentistry and suggests that dentists can act as a group to increase or decrease agency costs, primarily by controlling the bad actors who damage the value of all dentists.

  14. Multi-Agent Inference in Social Networks: A Finite Population Learning Approach

    PubMed Central

    Tong, Xin; Zeng, Yao

    2016-01-01

    When people in a society want to make inference about some parameter, each person may want to use data collected by other people. Information (data) exchange in social networks is usually costly, so to make reliable statistical decisions, people need to trade off the benefits and costs of information acquisition. Conflicts of interests and coordination problems will arise in the process. Classical statistics does not consider people’s incentives and interactions in the data collection process. To address this imperfection, this work explores multi-agent Bayesian inference problems with a game theoretic social network model. Motivated by our interest in aggregate inference at the societal level, we propose a new concept, finite population learning, to address whether with high probability, a large fraction of people in a given finite population network can make “good” inference. Serving as a foundation, this concept enables us to study the long run trend of aggregate inference quality as population grows. PMID:27076691

  15. Multi-Agent Inference in Social Networks: A Finite Population Learning Approach.

    PubMed

    Fan, Jianqing; Tong, Xin; Zeng, Yao

    When people in a society want to make inference about some parameter, each person may want to use data collected by other people. Information (data) exchange in social networks is usually costly, so to make reliable statistical decisions, people need to trade off the benefits and costs of information acquisition. Conflicts of interests and coordination problems will arise in the process. Classical statistics does not consider people's incentives and interactions in the data collection process. To address this imperfection, this work explores multi-agent Bayesian inference problems with a game theoretic social network model. Motivated by our interest in aggregate inference at the societal level, we propose a new concept, finite population learning, to address whether with high probability, a large fraction of people in a given finite population network can make "good" inference. Serving as a foundation, this concept enables us to study the long run trend of aggregate inference quality as population grows.

  16. Health care supply networks in tightly and loosely coupled structures: exploration using agent-based modelling

    NASA Astrophysics Data System (ADS)

    Kanagarajah, A.; Parker, D.; Xu, H.

    2010-03-01

    Health care supply networks are multi-faceted complex structures. This article discusses architecture of complex systems and an agent-based modelling framework to study health care supply networks and their impact on patient safety, economics, and workloads. Here we demonstrate the application of a safety dynamics model proposed by Cook and Rasmussen (2005, '"Going Solid": A Model of System Dynamics and Consequences for Patient Safety', Quality & Safety in Health Care, 14, 67-84.) to study a health care system, using a hypothetical simulation of an emergency department as a representative unit and its dynamic behaviour. By means of simulation, this article demonstrates the non-linear behaviours of a health service unit and its complexities; and how the safety dynamic model may be used to evaluate the various policy and design aspects of health care supply networks.

  17. Friendship Network and Dental Brushing Behavior among Middle School Students: An Agent Based Modeling Approach.

    PubMed

    Sadeghipour, Maryam; Khoshnevisan, Mohammad Hossein; Jafari, Afshin; Shariatpanahi, Seyed Peyman

    2017-01-01

    By using a standard questionnaire, the level of dental brushing frequency was assessed among 201 adolescent female middle school students in Tehran. The initial assessment was repeated after 5 months, in order to observe the dynamics in dental health behavior level. Logistic Regression model was used to evaluate the correlation among individuals' dental health behavior in their social network. A significant correlation on dental brushing habits was detected among groups of friends. This correlation was further spread over the network within the 5 months period. Moreover, it was identified that the average brushing level was improved within the 5 months period. Given that there was a significant correlation between social network's nodes' in-degree value, and brushing level, it was suggested that the observed improvement was partially due to more popularity of individuals with better tooth brushing habit. Agent Based Modeling (ABM) was used to demonstrate the dynamics of dental brushing frequency within a sample of friendship network. Two models with static and dynamic assumptions for the network structure were proposed. The model with dynamic network structure successfully described the dynamics of dental health behavior. Based on this model, on average, every 43 weeks a student changes her brushing habit due to learning from her friends. Finally, three training scenarios were tested by these models in order to evaluate their effectiveness. When training more popular students, considerable improvement in total students' brushing frequency was demonstrated by simulation results.

  18. Networked Guidance and Control for Mobile Multi-Agent Systems: A Multi-Terminal (Network) Information Theoretic Approach

    DTIC Science & Technology

    2014-11-04

    AFRL-OSR-VA-TR-2014-0311 Networked Guidance and Control for Mobile Multi-Agent Nuno Martins MARYLAND UNIV COLLEGE PARK Final Report 11/04/2014...sponsored  work  on  fundamental  aspects  of  the  following  research   themes :       • Analysis  and  design  of...Systems, Ph.D. Thesis, University of Maryland at College Park , 2013 [4] Aditya Mahajan, Nuno C. Martins, Michael C. Rotkowitz and Serdar Yuksel

  19. Self-organized criticality in a network of economic agents with finite consumption

    NASA Astrophysics Data System (ADS)

    da Cruz, João P.; Lind, Pedro G.

    2012-02-01

    We introduce a minimal agent model to explain the emergence of heavy-tailed return distributions as a result of self-organized criticality. The model assumes that agents trade their economic outputs with each other composing a complex network of agents and connections. Further, the incoming degree of an agent is proportional to the demand on its goods, while its outgoing degree is proportional to the supply. The model considers a collection of economic agents which are attracted to establish connections among them to make an exchange at a price formed by supply and demand. With our model we are able to reproduce the evolution of the return of macroscopic quantities (indices) and to correctly retrieve the non-trivial exponent value characterizing the amplitude of drops in several indices in financial markets, relating it to the underlying topology of connections. The distribution of drops in empirical data is obtained by counting the number of successive time-steps for which a decrease in the index value is observed. All eight financial indexes show an exponent m∼5/2. Finally, we present mean-field calculations of the critical exponents, and of the scaling relation m=3/2 γ-1 between the exponent m for the distribution of drops and the topological exponent γ for the degree distribution.

  20. Thermodynamics of firms' growth

    PubMed Central

    Zambrano, Eduardo; Hernando, Alberto; Hernando, Ricardo; Plastino, Angelo

    2015-01-01

    The distribution of firms' growth and firms' sizes is a topic under intense scrutiny. In this paper, we show that a thermodynamic model based on the maximum entropy principle, with dynamical prior information, can be constructed that adequately describes the dynamics and distribution of firms' growth. Our theoretical framework is tested against a comprehensive database of Spanish firms, which covers, to a very large extent, Spain's economic activity, with a total of 1 155 142 firms evolving along a full decade. We show that the empirical exponent of Pareto's law, a rule often observed in the rank distribution of large-size firms, is explained by the capacity of economic system for creating/destroying firms, and that can be used to measure the health of a capitalist-based economy. Indeed, our model predicts that when the exponent is larger than 1, creation of firms is favoured; when it is smaller than 1, destruction of firms is favoured instead; and when it equals 1 (matching Zipf's law), the system is in a full macroeconomic equilibrium, entailing ‘free’ creation and/or destruction of firms. For medium and smaller firm sizes, the dynamical regime changes, the whole distribution can no longer be fitted to a single simple analytical form and numerical prediction is required. Our model constitutes the basis for a full predictive framework regarding the economic evolution of an ensemble of firms. Such a structure can be potentially used to develop simulations and test hypothetical scenarios, such as economic crisis or the response to specific policy measures. PMID:26510828

  1. Hydrogel-polyurethane interpenetrating network material as an advanced draw agent for forward osmosis process.

    PubMed

    Wei, Jing; Low, Ze-Xian; Ou, Ranwen; Simon, George P; Wang, Huanting

    2016-06-01

    Water desalination and purification are critical to address the global issue of the shortage of clean water. Forward osmosis (FO) desalination is an emerging low-cost technology for clean water production from saline water. The lack of a suitable draw agent is one of hurdle for the commercialization of FO desalination technology. Recently, the thermoresponsive hydrogel has been demonstrated to be a potential draw agent for the FO process. However, the commonly used hydrogel powder shows a much lower flux than other kind of draw agent such as inorganic salts. In this work, a hydrogel-polyurethane interpenetrating network (HPIPN) with monolith form was prepared by controlling the radical polymerization of the monomers (N-isopropylacrylamide and sodium acrylate) in the macropores (∼400 μm) of commercial polyurethane foam (PUF). These HPIPN composites show a flux as high as 17.9 LMH, which is nearly 8 times than that of hydrogel powders (2.2 LMH). The high flux is attributed to the 3-D continuous hydrogel-polyurethane interpenetrating network, which can effectively enhance the water transport inside the monolith. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Product Design Network Self-contextualization: Enterprise Knowledge-Based Approach and Agent-Based Technological Framework

    NASA Astrophysics Data System (ADS)

    Levashova, Tatiana; Sandkuhl, Kurt; Shilov, Nikolay; Smirnov, Alexander; Tarasov, Vladimir

    The paper introduces self-contextualization in a service infrastructure for product design networks as novel application field for multi-agent technology. The main contributions of this paper are (1) identification of requirements from product design networks to the supporting service infrastructure, (2) the use of enterprise knowledge modelling techniques for the representation of computable context models, (3) a technological framework based on agent technology for self-contextualization based on enterprise knowledge models.

  3. Friendship Network and Dental Brushing Behavior among Middle School Students: An Agent Based Modeling Approach

    PubMed Central

    Sadeghipour, Maryam; Khoshnevisan, Mohammad Hossein; Jafari, Afshin; Shariatpanahi, Seyed Peyman

    2017-01-01

    By using a standard questionnaire, the level of dental brushing frequency was assessed among 201 adolescent female middle school students in Tehran. The initial assessment was repeated after 5 months, in order to observe the dynamics in dental health behavior level. Logistic Regression model was used to evaluate the correlation among individuals’ dental health behavior in their social network. A significant correlation on dental brushing habits was detected among groups of friends. This correlation was further spread over the network within the 5 months period. Moreover, it was identified that the average brushing level was improved within the 5 months period. Given that there was a significant correlation between social network’s nodes’ in-degree value, and brushing level, it was suggested that the observed improvement was partially due to more popularity of individuals with better tooth brushing habit. Agent Based Modeling (ABM) was used to demonstrate the dynamics of dental brushing frequency within a sample of friendship network. Two models with static and dynamic assumptions for the network structure were proposed. The model with dynamic network structure successfully described the dynamics of dental health behavior. Based on this model, on average, every 43 weeks a student changes her brushing habit due to learning from her friends. Finally, three training scenarios were tested by these models in order to evaluate their effectiveness. When training more popular students, considerable improvement in total students’ brushing frequency was demonstrated by simulation results. PMID:28103260

  4. Distributed Synchronization in Networks of Agent Systems With Nonlinearities and Random Switchings.

    PubMed

    Tang, Yang; Gao, Huijun; Zou, Wei; Kurths, Jürgen

    2013-02-01

    In this paper, the distributed synchronization problem of networks of agent systems with controllers and nonlinearities subject to Bernoulli switchings is investigated. Controllers and adaptive updating laws injected in each vertex of networks depend on the state information of its neighborhood. Three sets of Bernoulli stochastic variables are introduced to describe the occurrence probabilities of distributed adaptive controllers, updating laws and nonlinearities, respectively. By the Lyapunov functions method, we show that the distributed synchronization of networks composed of agent systems with multiple randomly occurring nonlinearities, multiple randomly occurring controllers, and multiple randomly occurring updating laws can be achieved in mean square under certain criteria. The conditions derived in this paper can be solved by semi-definite programming. Moreover, by mathematical analysis, we find that the coupling strength, the probabilities of the Bernoulli stochastic variables, and the form of nonlinearities have great impacts on the convergence speed and the terminal control strength. The synchronization criteria and the observed phenomena are demonstrated by several numerical simulation examples. In addition, the advantage of distributed adaptive controllers over conventional adaptive controllers is illustrated.

  5. Insurance within the Firm

    ERIC Educational Resources Information Center

    Guiso, Luigi; Pistaferri, Luigi; Schivardi, Fabiano

    2005-01-01

    We evaluate the allocation of risk between firms and their workers using matched employer-employee panel data. Unlike previous contributions, this paper focuses on idiosyncratic shocks to the firm, which are the correct empirical counterpart of the theoretical notion of diversifiable risk. We allow for both temporary and permanent shocks to output…

  6. Insurance within the Firm

    ERIC Educational Resources Information Center

    Guiso, Luigi; Pistaferri, Luigi; Schivardi, Fabiano

    2005-01-01

    We evaluate the allocation of risk between firms and their workers using matched employer-employee panel data. Unlike previous contributions, this paper focuses on idiosyncratic shocks to the firm, which are the correct empirical counterpart of the theoretical notion of diversifiable risk. We allow for both temporary and permanent shocks to output…

  7. Consensus problem of networked multi-agent systems with constant communication delay: stochastic switching topology case

    NASA Astrophysics Data System (ADS)

    Chen, Jinhuan; Xie, Dongmei; Yu, Mei

    2012-09-01

    This article proposes an observer-based control strategy for networked multi-agent systems with constant communication delay and stochastic switching topology. First, using the system transformation method, the mean-square consensus problem of multi-agent systems can be converted into the mean-square stability problem of an equivalent system, and some equivalent conditions concerning the mean-square consensus are presented. Then, an example is given to illustrate that the connection weights should be regarded as the parameters to be designed, since they have a great effect on the mean-square consensus of multi-agent systems. By choosing appropriate connection weights, the mean-square consensus problem can be converted into the mean-square stabilisation problem of N-1 delay systems with stochastic switching signal, whose related observer-based stabilisability criteria can be established in the form of linear matrix inequalities (LMIs). Furthermore, if the LMIs are feasible, the multi-agent systems achieve mean-square consensus if and only if the union of graphs in the switching topology set has a directed spanning tree. Finally, numerical simulations are given to illustrate our results.

  8. Nature as a network of morphological infocomputational processes for cognitive agents

    NASA Astrophysics Data System (ADS)

    Dodig-Crnkovic, Gordana

    2017-01-01

    This paper presents a view of nature as a network of infocomputational agents organized in a dynamical hierarchy of levels. It provides a framework for unification of currently disparate understandings of natural, formal, technical, behavioral and social phenomena based on information as a structure, differences in one system that cause the differences in another system, and computation as its dynamics, i.e. physical process of morphological change in the informational structure. We address some of the frequent misunderstandings regarding the natural/morphological computational models and their relationships to physical systems, especially cognitive systems such as living beings. Natural morphological infocomputation as a conceptual framework necessitates generalization of models of computation beyond the traditional Turing machine model presenting symbol manipulation, and requires agent-based concurrent resource-sensitive models of computation in order to be able to cover the whole range of phenomena from physics to cognition. The central role of agency, particularly material vs. cognitive agency is highlighted.

  9. Consensus in averager-copier-voter networks of moving dynamical agents

    NASA Astrophysics Data System (ADS)

    Shang, Yilun

    2017-02-01

    This paper deals with a hybrid opinion dynamics comprising averager, copier, and voter agents, which ramble as random walkers on a spatial network. Agents exchange information following some deterministic and stochastic protocols if they reside at the same site in the same time. Based on stochastic stability of Markov chains, sufficient conditions guaranteeing consensus in the sense of almost sure convergence have been obtained. The ultimate consensus state is identified in the form of an ergodicity result. Simulation studies are performed to validate the effectiveness and availability of our theoretical results. The existence/non-existence of voters and the proportion of them are unveiled to play key roles during the consensus-reaching process.

  10. Neural network-based adaptive consensus tracking control for multi-agent systems under actuator faults

    NASA Astrophysics Data System (ADS)

    Zhao, Lin; Jia, Yingmin

    2016-06-01

    In this paper, a distributed output feedback consensus tracking control scheme is proposed for second-order multi-agent systems in the presence of uncertain nonlinear dynamics, external disturbances, input constraints, and partial loss of control effectiveness. The proposed controllers incorporate reduced-order filters to account for the unmeasured states, and the neural networks technique is implemented to approximate the uncertain nonlinear dynamics in the synthesis of control algorithms. In order to compensate the partial loss of actuator effectiveness faults, fault-tolerant parts are included in controllers. Using the Lyapunov approach and graph theory, it is proved that the controllers guarantee a group of agents that simultaneously track a common time-varying state of leader, even when the state of leader is available only to a subset of the members of a group. Simulation results are provided to demonstrate the effectiveness of the proposed consensus tracking method.

  11. Advancing complementary and alternative medicine through social network analysis and agent-based modeling.

    PubMed

    Frantz, Terrill L

    2012-01-01

    This paper introduces the contemporary perspectives and techniques of social network analysis (SNA) and agent-based modeling (ABM) and advocates applying them to advance various aspects of complementary and alternative medicine (CAM). SNA and ABM are invaluable methods for representing, analyzing and projecting complex, relational, social phenomena; they provide both an insightful vantage point and a set of analytic tools that can be useful in a wide range of contexts. Applying these methods in the CAM context can aid the ongoing advances in the CAM field, in both its scientific aspects and in developing broader acceptance in associated stakeholder communities.

  12. Finding shared decisions in stakeholder networks: An agent-based approach

    NASA Astrophysics Data System (ADS)

    Le Pira, Michela; Inturri, Giuseppe; Ignaccolo, Matteo; Pluchino, Alessandro; Rapisarda, Andrea

    2017-01-01

    We address the problem of a participatory decision-making process where a shared priority list of alternatives has to be obtained while avoiding inconsistent decisions. An agent-based model (ABM) is proposed to mimic this process in different social networks of stakeholders who interact according to an opinion dynamics model. Simulations' results show the efficacy of interaction in finding a transitive and, above all, shared decision. These findings are in agreement with real participation experiences regarding transport planning decisions and can give useful suggestions on how to plan an effective participation process for sustainable policy-making based on opinion consensus.

  13. Adaptive fuzzy wavelet network control of second order multi-agent systems with unknown nonlinear dynamics.

    PubMed

    Taheri, Mehdi; Sheikholeslam, Farid; Najafi, Majddedin; Zekri, Maryam

    2017-07-01

    In this paper, consensus problem is considered for second order multi-agent systems with unknown nonlinear dynamics under undirected graphs. A novel distributed control strategy is suggested for leaderless systems based on adaptive fuzzy wavelet networks. Adaptive fuzzy wavelet networks are employed to compensate for the effect of unknown nonlinear dynamics. Moreover, the proposed method is developed for leader following systems and leader following systems with state time delays. Lyapunov functions are applied to prove uniformly ultimately bounded stability of closed loop systems and to obtain adaptive laws. Three simulation examples are presented to illustrate the effectiveness of the proposed control algorithms. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

  14. Chimera states in a network-organized public goods game with destructive agents.

    PubMed

    Kouvaris, Nikos E; Requejo, Rubén J; Hizanidis, Johanne; Díaz-Guilera, Albert

    2016-12-01

    We found that a network-organized metapopulation of cooperators, defectors, and destructive agents playing the public goods game with mutations can collectively reach global synchronization or chimera states. Global synchronization is accompanied by a collective periodic burst of cooperation, whereas chimera states reflect the tendency of the networked metapopulation to be fragmented in clusters of synchronous and incoherent bursts of cooperation. Numerical simulations have shown that the system's dynamics switches between these two steady states through a first order transition. Depending on the parameters determining the dynamical and topological properties, chimera states with different numbers of coherent and incoherent clusters are observed. Our results present the first systematic study of chimera states and their characterization in the context of evolutionary game theory. This provides a valuable insight into the details of their occurrence, extending the relevance of such states to natural and social systems.

  15. Chimera states in a network-organized public goods game with destructive agents

    NASA Astrophysics Data System (ADS)

    Kouvaris, Nikos E.; Requejo, Rubén J.; Hizanidis, Johanne; Díaz-Guilera, Albert

    2016-12-01

    We found that a network-organized metapopulation of cooperators, defectors, and destructive agents playing the public goods game with mutations can collectively reach global synchronization or chimera states. Global synchronization is accompanied by a collective periodic burst of cooperation, whereas chimera states reflect the tendency of the networked metapopulation to be fragmented in clusters of synchronous and incoherent bursts of cooperation. Numerical simulations have shown that the system's dynamics switches between these two steady states through a first order transition. Depending on the parameters determining the dynamical and topological properties, chimera states with different numbers of coherent and incoherent clusters are observed. Our results present the first systematic study of chimera states and their characterization in the context of evolutionary game theory. This provides a valuable insight into the details of their occurrence, extending the relevance of such states to natural and social systems.

  16. AN AGENT-BASED SIMULATION STUDY OF A COMPLEX ADAPTIVE COLLABORATION NETWORK

    SciTech Connect

    Ozmen, Ozgur; Smith, Jeffrey; Yilmaz, Levent

    2013-01-01

    One of the most significant problems in organizational scholarship is to discern how social collectives govern, organize, and coordinate the actions of individuals to achieve collective outcomes. The collectives are usually interpreted as complex adaptive systems (CAS). The understanding of CAS is more likely to arise with the help of computer-based simulations. In this tutorial, using agent-based modeling approach, a complex adaptive social communication network model is introduced. The objective is to present the underlying dynamics of the system in a form of computer simulation that enables analyzing the impacts of various mechanisms on network topologies and emergent behaviors. The ultimate goal is to further our understanding of the dynamics in the system and facilitate developing informed policies for decision-makers.

  17. A Multi Agent-Based Framework for Simulating Household PHEV Distribution and Electric Distribution Network Impact

    SciTech Connect

    Cui, Xiaohui; Liu, Cheng; Kim, Hoe Kyoung; Kao, Shih-Chieh; Tuttle, Mark A; Bhaduri, Budhendra L

    2011-01-01

    The variation of household attributes such as income, travel distance, age, household member, and education for different residential areas may generate different market penetration rates for plug-in hybrid electric vehicle (PHEV). Residential areas with higher PHEV ownership could increase peak electric demand locally and require utilities to upgrade the electric distribution infrastructure even though the capacity of the regional power grid is under-utilized. Estimating the future PHEV ownership distribution at the residential household level can help us understand the impact of PHEV fleet on power line congestion, transformer overload and other unforeseen problems at the local residential distribution network level. It can also help utilities manage the timing of recharging demand to maximize load factors and utilization of existing distribution resources. This paper presents a multi agent-based simulation framework for 1) modeling spatial distribution of PHEV ownership at local residential household level, 2) discovering PHEV hot zones where PHEV ownership may quickly increase in the near future, and 3) estimating the impacts of the increasing PHEV ownership on the local electric distribution network with different charging strategies. In this paper, we use Knox County, TN as a case study to show the simulation results of the agent-based model (ABM) framework. However, the framework can be easily applied to other local areas in the US.

  18. Efficient method for comprehensive computation of agent-level epidemic dissemination in networks.

    PubMed

    Nakamura, Gilberto M; Monteiro, Ana Carolina P; Cardoso, George C; Martinez, Alexandre S

    2017-01-20

    Susceptible-infected (SI) and susceptible-infected-susceptible (SIS) are simple agent-based models often employed in epidemic studies. Both models describe the time evolution of infectious diseases in networks whose vertices are either susceptible (S) or infected (I) agents. Precise estimation for disease spreading is one of the major goals in epidemic studies but often restricted to heavy numerical simulations. Analytic methods using operatorial content are subject to the asymmetric eigenvalue problem, limiting the use of perturbative methods. Numerical methods are limited to small populations, since the vector space increases exponentially with population size N. Here, we propose the use of the squared norm of the probability vector to obtain an algebraic equation, which permits the evaluation of stationary states in Markov processes. The equation requires the eigenvalues of symmetrized time generators and takes full advantage of symmetries, reducing the time evolution to an O(N) sparse problem. The calculation of eigenvalues employs quantum many-body techniques, while the standard perturbation theory accounts for small modifications to the network topology.

  19. Efficient method for comprehensive computation of agent-level epidemic dissemination in networks

    PubMed Central

    Nakamura, Gilberto M.; Monteiro, Ana Carolina P.; Cardoso, George C.; Martinez, Alexandre S.

    2017-01-01

    Susceptible-infected (SI) and susceptible-infected-susceptible (SIS) are simple agent-based models often employed in epidemic studies. Both models describe the time evolution of infectious diseases in networks whose vertices are either susceptible (S) or infected (I) agents. Precise estimation for disease spreading is one of the major goals in epidemic studies but often restricted to heavy numerical simulations. Analytic methods using operatorial content are subject to the asymmetric eigenvalue problem, limiting the use of perturbative methods. Numerical methods are limited to small populations, since the vector space increases exponentially with population size N. Here, we propose the use of the squared norm of the probability vector to obtain an algebraic equation, which permits the evaluation of stationary states in Markov processes. The equation requires the eigenvalues of symmetrized time generators and takes full advantage of symmetries, reducing the time evolution to an O(N) sparse problem. The calculation of eigenvalues employs quantum many-body techniques, while the standard perturbation theory accounts for small modifications to the network topology. PMID:28106086

  20. Efficient method for comprehensive computation of agent-level epidemic dissemination in networks

    NASA Astrophysics Data System (ADS)

    Nakamura, Gilberto M.; Monteiro, Ana Carolina P.; Cardoso, George C.; Martinez, Alexandre S.

    2017-01-01

    Susceptible-infected (SI) and susceptible-infected-susceptible (SIS) are simple agent-based models often employed in epidemic studies. Both models describe the time evolution of infectious diseases in networks whose vertices are either susceptible (S) or infected (I) agents. Precise estimation for disease spreading is one of the major goals in epidemic studies but often restricted to heavy numerical simulations. Analytic methods using operatorial content are subject to the asymmetric eigenvalue problem, limiting the use of perturbative methods. Numerical methods are limited to small populations, since the vector space increases exponentially with population size N. Here, we propose the use of the squared norm of the probability vector to obtain an algebraic equation, which permits the evaluation of stationary states in Markov processes. The equation requires the eigenvalues of symmetrized time generators and takes full advantage of symmetries, reducing the time evolution to an O(N) sparse problem. The calculation of eigenvalues employs quantum many-body techniques, while the standard perturbation theory accounts for small modifications to the network topology.

  1. Evaluating network analysis and agent based modeling for investigating the stability of commercial air carrier schedules

    NASA Astrophysics Data System (ADS)

    Conway, Sheila Ruth

    For a number of years, the United States Federal Government has been formulating the Next Generation Air Transportation System plans for National Airspace System improvement. These improvements attempt to address air transportation holistically, but often address individual improvements in one arena such as ground or in-flight equipment. In fact, air transportation system designers have had only limited success using traditional Operations Research and parametric modeling approaches in their analyses of innovative operations. They need a systemic methodology for modeling of safety-critical infrastructure that is comprehensive, objective, and sufficiently concrete, yet simple enough to be deployed with reasonable investment. The methodology must also be amenable to quantitative analysis so issues of system safety and stability can be rigorously addressed. The literature suggests that both agent-based models and network analysis techniques may be useful for complex system development and analysis. The purpose of this research is to evaluate these two techniques as applied to analysis of commercial air carrier schedule (route) stability in daily operations, an important component of air transportation. Airline-like routing strategies are used to educe essential elements of applying the method. Two main models are developed, one investigating the network properties of the route structure, the other an Agent-based approach. The two methods are used to predict system properties at a macro-level. These findings are compared to observed route network performance measured by adherence to a schedule to provide validation of the results. Those interested in complex system modeling are provided some indication as to when either or both of the techniques would be applicable. For aviation policy makers, the results point to a toolset capable of providing insight into the system behavior during the formative phases of development and transformation with relatively low investment

  2. Firms, crowds, and innovation.

    PubMed

    Felin, Teppo; Lakhani, Karim R; Tushman, Michael L

    2017-05-01

    The purpose of this article is to suggest a (preliminary) taxonomy and research agenda for the topic of "firms, crowds, and innovation" and to provide an introduction to the associated special issue. We specifically discuss how various crowd-related phenomena and practices-for example, crowdsourcing, crowdfunding, user innovation, and peer production-relate to theories of the firm, with particular attention on "sociality" in firms and markets. We first briefly review extant theories of the firm and then discuss three theoretical aspects of sociality related to crowds in the context of strategy, organizations, and innovation: (1) the functions of sociality (sociality as extension of rationality, sociality as sensing and signaling, sociality as matching and identity), (2) the forms of sociality (independent/aggregate and interacting/emergent forms of sociality), and (3) the failures of sociality (misattribution and misapplication). We conclude with an outline of future research directions and introduce the special issue papers and essays.

  3. MAE-FMD: multi-agent evolutionary method for functional module detection in protein-protein interaction networks.

    PubMed

    Ji, Jun Zhong; Jiao, Lang; Yang, Cui Cui; Lv, Jia Wei; Zhang, Ai Dong

    2014-09-30

    Studies of functional modules in a Protein-Protein Interaction (PPI) network contribute greatly to the understanding of biological mechanisms. With the development of computing science, computational approaches have played an important role in detecting functional modules. We present a new approach using multi-agent evolution for detection of functional modules in PPI networks. The proposed approach consists of two stages: the solution construction for agents in a population and the evolutionary process of computational agents in a lattice environment, where each agent corresponds to a candidate solution to the detection problem of functional modules in a PPI network. First, the approach utilizes a connection-based encoding scheme to model an agent, and employs a random-walk behavior merged topological characteristics with functional information to construct a solution. Next, it applies several evolutionary operators, i.e., competition, crossover, and mutation, to realize information exchange among agents as well as solution evolution. Systematic experiments have been conducted on three benchmark testing sets of yeast networks. Experimental results show that the approach is more effective compared to several other existing algorithms. The algorithm has the characteristics of outstanding recall, F-measure, sensitivity and accuracy while keeping other competitive performances, so it can be applied to the biological study which requires high accuracy.

  4. Use of Caries Prevention Agents in Children: Findings from the Dental Practice-based Research Network

    PubMed Central

    Riley, Joseph L.; Richman, Joshua S.; Rindal, D. Brad; Fellows, Jeffrey L.; Qvist, Vibeke; Gilbert, Gregg H.; Gordan, Valeria V.

    2010-01-01

    Purpose Scientific evidence supports the application of caries preventive agents in children and this knowledge must transfer into the practice of dentistry. There is little multi-region data that allow for comparisons of practice patterns between types of dental practices and geographic regions. The aim of this study was to characterize the use of caries preventive agents in pediatric patients in a large multi-region sample of dental practices. Methods This study surveyed Dental Practice-based Research Network dentists who perform restorative dentistry in their practices. The survey asked a range of questions about caries risk assessment and use of prevention techniques in children ages 6-18. Results Dental sealants (69%) or in-office fluoride (82%) were the most commonly used of the caries preventive regimens. The recommendation of at-home caries preventive agents ranged from 36%-7%, with non-prescription fluoride rinse the most common. Dentists who practiced in a large group practice model and dentists from the Scandinavian region more frequently use caries risk assessment than regions that were predominately dentists in private practice. Whether or not dentists used caries risk assessment with their pediatric patients was poorly correlated with the likelihood of actually using caries preventive treatments on patients. Conclusion Although dentists reported the use of some form of in-office caries prevention, there was considerable variability across practices. These differences could represent a lack of consensus across practicing dentists about the benefits of caries preventive agents or a function of differing financial incentives or patient pools with differing levels of overall caries risk. PMID:21180672

  5. Innovating Firms and Aggregate Innovation.

    ERIC Educational Resources Information Center

    Klette, Tor Jakob; Kortum, Samuel

    2004-01-01

    We develop a parsimonious model of innovation to confront firm-level evidence. It captures the dynamics of individual heterogeneous firms, describes the behavior of an industry with firm entry and exit, and delivers a general equilibrium model of technological change. While unifying the theoretical analysis of firms, industries, and the aggregate…

  6. Innovating Firms and Aggregate Innovation.

    ERIC Educational Resources Information Center

    Klette, Tor Jakob; Kortum, Samuel

    2004-01-01

    We develop a parsimonious model of innovation to confront firm-level evidence. It captures the dynamics of individual heterogeneous firms, describes the behavior of an industry with firm entry and exit, and delivers a general equilibrium model of technological change. While unifying the theoretical analysis of firms, industries, and the aggregate…

  7. [Methodological novelties applied to the anthropology of food: agent-based models and social networks analysis].

    PubMed

    Díaz Córdova, Diego

    2016-01-01

    The aim of this article is to introduce two methodological strategies that have not often been utilized in the anthropology of food: agent-based models and social networks analysis. In order to illustrate these methods in action, two cases based in materials typical of the anthropology of food are presented. For the first strategy, fieldwork carried out in Quebrada de Humahuaca (province of Jujuy, Argentina) regarding meal recall was used, and for the second, elements of the concept of "domestic consumption strategies" applied by Aguirre were employed. The underlying idea is that, given that eating is recognized as a "total social fact" and, therefore, as a complex phenomenon, the methodological approach must also be characterized by complexity. The greater the number of methods utilized (with the appropriate rigor), the better able we will be to understand the dynamics of feeding in the social environment.

  8. Pervasive community care platform: Ambient Intelligence leveraging sensor networks and mobile agents

    NASA Astrophysics Data System (ADS)

    Su, Chuan-Jun; Chiang, Chang-Yu

    2014-04-01

    Several powerful trends are contributing to an aging of much of the world's population, especially in economically developed countries. To mitigate the negative effects of rapidly ageing populations, societies must act early to plan for the welfare, medical care and residential arrangements of their senior citizens, and for the manpower and associated training needed to execute these plans. This paper describes the development of an Ambient Intelligent Community Care Platform (AICCP), which creates an environment of Ambient Intelligence through the use of sensor network and mobile agent (MA) technologies. The AICCP allows caregivers to quickly and accurately locate their charges; access, update and share critical treatment and wellness data; and automatically archive all records. The AICCP presented in this paper is expected to enable caregivers and communities to offer pervasive, accurate and context-aware care services.

  9. The biocontrol agent Pseudomonas chlororaphis PA23 primes Brassica napus defenses through distinct gene networks.

    PubMed

    Duke, Kelly A; Becker, Michael G; Girard, Ian J; Millar, Jenna L; Dilantha Fernando, W G; Belmonte, Mark F; de Kievit, Teresa R

    2017-06-19

    The biological control agent Pseudomonas chlororaphis PA23 is capable of protecting Brassica napus (canola) from the necrotrophic fungus Sclerotinia sclerotiorum via direct antagonism. While we have elucidated bacterial genes and gene products responsible biocontrol, little is known about how the host plant responds to bacterial priming on the leaf surface, including global changes in gene activity in the presence and absence of S. sclerotiorum. Application of PA23 to the aerial surfaces of canola plants reduced the number of S. sclerotiorum lesion-forming petals by 91.1%. RNA sequencing of the host pathogen interface showed that pretreatment with PA23 reduced the number of genes upregulated in response to S. sclerotiorum by 16-fold. By itself, PA23 activated unique defense networks indicative of defense priming. Genes encoding MAMP-triggered immunity receptors detecting flagellin and peptidoglycan were downregulated in PA23 only-treated plants, consistent with post-stimulus desensitization. Downstream, we observed reactive oxygen species (ROS) production involving low levels of H2O2 and overexpression of genes associated with glycerol-3-phosphate (G3P)-mediated systemic acquired resistance (SAR). Leaf chloroplasts exhibited increased thylakoid membrane structures and chlorophyll content, while lipid metabolic processes were upregulated. In addition to directly antagonizing S. sclerotiorum, PA23 primes the plant defense response through induction of unique local and systemic defense networks. This study provides novel insight into the effects of biocontrol agents applied to the plant phyllosphere. Understanding these interactions will aid in the development of biocontrol systems as an alternative to chemical pesticides for protection of important crop systems.

  10. Combining Bayesian Networks and Agent Based Modeling to develop a decision-support model in Vietnam

    NASA Astrophysics Data System (ADS)

    Nong, Bao Anh; Ertsen, Maurits; Schoups, Gerrit

    2016-04-01

    Complexity and uncertainty in natural resources management have been focus themes in recent years. Within these debates, with the aim to define an approach feasible for water management practice, we are developing an integrated conceptual modeling framework for simulating decision-making processes of citizens, in our case in the Day river area, Vietnam. The model combines Bayesian Networks (BNs) and Agent-Based Modeling (ABM). BNs are able to combine both qualitative data from consultants / experts / stakeholders, and quantitative data from observations on different phenomena or outcomes from other models. Further strengths of BNs are that the relationship between variables in the system is presented in a graphical interface, and that components of uncertainty are explicitly related to their probabilistic dependencies. A disadvantage is that BNs cannot easily identify the feedback of agents in the system once changes appear. Hence, ABM was adopted to represent the reaction among stakeholders under changes. The modeling framework is developed as an attempt to gain better understanding about citizen's behavior and factors influencing their decisions in order to reduce uncertainty in the implementation of water management policy.

  11. Modeling the Information Age Combat Model: An Agent-Based Simulation of Network Centric Operations

    NASA Technical Reports Server (NTRS)

    Deller, Sean; Rabadi, Ghaith A.; Bell, Michael I.; Bowling, Shannon R.; Tolk, Andreas

    2010-01-01

    The Information Age Combat Model (IACM) was introduced by Cares in 2005 to contribute to the development of an understanding of the influence of connectivity on force effectiveness that can eventually lead to quantitative prediction and guidelines for design and employment. The structure of the IACM makes it clear that the Perron-Frobenius Eigenvalue is a quantifiable metric with which to measure the organization of a networked force. The results of recent experiments presented in Deller, et aI., (2009) indicate that the value of the Perron-Frobenius Eigenvalue is a significant measurement of the performance of an Information Age combat force. This was accomplished through the innovative use of an agent-based simulation to model the IACM and represents an initial contribution towards a new generation of combat models that are net-centric instead of using the current platform-centric approach. This paper describes the intent, challenges, design, and initial results of this agent-based simulation model.

  12. Agent-based model of angiogenesis simulates capillary sprout initiation in multicellular networks.

    PubMed

    Walpole, J; Chappell, J C; Cluceru, J G; Mac Gabhann, F; Bautch, V L; Peirce, S M

    2015-09-01

    Many biological processes are controlled by both deterministic and stochastic influences. However, efforts to model these systems often rely on either purely stochastic or purely rule-based methods. To better understand the balance between stochasticity and determinism in biological processes a computational approach that incorporates both influences may afford additional insight into underlying biological mechanisms that give rise to emergent system properties. We apply a combined approach to the simulation and study of angiogenesis, the growth of new blood vessels from existing networks. This complex multicellular process begins with selection of an initiating endothelial cell, or tip cell, which sprouts from the parent vessels in response to stimulation by exogenous cues. We have constructed an agent-based model of sprouting angiogenesis to evaluate endothelial cell sprout initiation frequency and location, and we have experimentally validated it using high-resolution time-lapse confocal microscopy. ABM simulations were then compared to a Monte Carlo model, revealing that purely stochastic simulations could not generate sprout locations as accurately as the rule-informed agent-based model. These findings support the use of rule-based approaches for modeling the complex mechanisms underlying sprouting angiogenesis over purely stochastic methods.

  13. Optimal and event-based networked control of physically interconnected systems and multi-agent systems

    NASA Astrophysics Data System (ADS)

    Demir, Ozan; Lunze, Jan

    2014-01-01

    Many interconnected systems like vehicle platoons or energy networks consist of similar or identical subsystems. The subsystem interconnections are either caused by the physical relations among the subsystems or have to be introduced by the controller to cope with cooperative control goals. This paper proposes strategies to reduce the complexity of the controller design problem (offline information reduction) and to reduce the amount of the system information, which is necessary for the implementation of the designed controller (online information reduction). It consists of two parts. The first part deals with the linear quadratic regulator (LQR) design problem for interconnected systems. A decomposition based on a state transformation is introduced, which allows to design the optimal controller for the interconnected system by considering modified subsystems separately. The proposed decomposition approach can be uniformly applied to multi-agent systems and physically interconnected systems. The second part of the paper introduces an event-based control strategy for multi-agent systems. The event-based control is a means to reduce the communication effort by invoking an information exchange among the subsystems only when the deviation between the estimated and current subsystem state exceeds an event threshold. An event-based controller is proposed, which mimics the continuous state-feedback controller with a desired precision. The relation between the event threshold and the approximation error is analysed.

  14. A mathematical framework for agent based models of complex biological networks.

    PubMed

    Hinkelmann, Franziska; Murrugarra, David; Jarrah, Abdul Salam; Laubenbacher, Reinhard

    2011-07-01

    Agent-based modeling and simulation is a useful method to study biological phenomena in a wide range of fields, from molecular biology to ecology. Since there is currently no agreed-upon standard way to specify such models, it is not always easy to use published models. Also, since model descriptions are not usually given in mathematical terms, it is difficult to bring mathematical analysis tools to bear, so that models are typically studied through simulation. In order to address this issue, Grimm et al. proposed a protocol for model specification, the so-called ODD protocol, which provides a standard way to describe models. This paper proposes an addition to the ODD protocol which allows the description of an agent-based model as a dynamical system, which provides access to computational and theoretical tools for its analysis. The mathematical framework is that of algebraic models, that is, time-discrete dynamical systems with algebraic structure. It is shown by way of several examples how this mathematical specification can help with model analysis. This mathematical framework can also accommodate other model types such as Boolean networks and the more general logical models, as well as Petri nets.

  15. Parallel computation with molecular-motor-propelled agents in nanofabricated networks

    PubMed Central

    Nicolau, Dan V.; Lard, Mercy; Korten, Till; van Delft, Falco C. M. J. M.; Persson, Malin; Bengtsson, Elina; Månsson, Alf; Diez, Stefan; Linke, Heiner; Nicolau, Dan V.

    2016-01-01

    The combinatorial nature of many important mathematical problems, including nondeterministic-polynomial-time (NP)-complete problems, places a severe limitation on the problem size that can be solved with conventional, sequentially operating electronic computers. There have been significant efforts in conceiving parallel-computation approaches in the past, for example: DNA computation, quantum computation, and microfluidics-based computation. However, these approaches have not proven, so far, to be scalable and practical from a fabrication and operational perspective. Here, we report the foundations of an alternative parallel-computation system in which a given combinatorial problem is encoded into a graphical, modular network that is embedded in a nanofabricated planar device. Exploring the network in a parallel fashion using a large number of independent, molecular-motor-propelled agents then solves the mathematical problem. This approach uses orders of magnitude less energy than conventional computers, thus addressing issues related to power consumption and heat dissipation. We provide a proof-of-concept demonstration of such a device by solving, in a parallel fashion, the small instance {2, 5, 9} of the subset sum problem, which is a benchmark NP-complete problem. Finally, we discuss the technical advances necessary to make our system scalable with presently available technology. PMID:26903637

  16. Can longitudinal generalized estimating equation models distinguish network influence and homophily? An agent-based modeling approach to measurement characteristics.

    PubMed

    Sauser Zachrison, Kori; Iwashyna, Theodore J; Gebremariam, Achamyeleh; Hutchins, Meghan; Lee, Joyce M

    2016-12-28

    Connected individuals (or nodes) in a network are more likely to be similar than two randomly selected nodes due to homophily and/or network influence. Distinguishing between these two influences is an important goal in network analysis, and generalized estimating equation (GEE) analyses of longitudinal dyadic network data are an attractive approach. It is not known to what extent such regressions can accurately extract underlying data generating processes. Therefore our primary objective is to determine to what extent, and under what conditions, does the GEE-approach recreate the actual dynamics in an agent-based model. We generated simulated cohorts with pre-specified network characteristics and attachments in both static and dynamic networks, and we varied the presence of homophily and network influence. We then used statistical regression and examined the GEE model performance in each cohort to determine whether the model was able to detect the presence of homophily and network influence. In cohorts with both static and dynamic networks, we find that the GEE models have excellent sensitivity and reasonable specificity for determining the presence or absence of network influence, but little ability to distinguish whether or not homophily is present. The GEE models are a valuable tool to examine for the presence of network influence in longitudinal data, but are quite limited with respect to homophily.

  17. An Agent-Based Discrete Collagen Fiber Network Model of Dynamic Traction Force-Induced Remodeling.

    PubMed

    Reinhardt, James W; Gooch, Keith

    2017-09-21

    We developed an agent-based model that incorporates repetitively applied traction force within a discrete fiber network to understand how microstructural properties of the network influence mechanical properties and traction force-induced remodeling. An important difference between our model and similar finite-element models is that by implementing more biologically-realistic dynamic traction, we can explore a greater range of matrix remodeling. Here, we validated our model by reproducing qualitative trends observed in three sets of experimental data reported by others: tensile and shear testing of cell-free collagen gels, collagen remodeling around a single isolated cell, and collagen remodeling between pairs of cells. In response to tensile and shear strain, simulated acellular networks exhibited biphasic stress-strain curves indicative of strain-stiffening. Our data support the notion that strain-stiffening might occur as individual fibrils successively align along the axis of strain and become engaged in tension. In simulations with a single, contractile cell, peak collagen displacement occurred closest to the cell and decreased with increasing distance. In simulations with two cells, compaction of collagen between cells appeared inversely related to the initial distance between cells. Further analysis revealed strain energy was relatively uniform around the outer surface of cells separated by 250 microns, but became increasingly non-uniform as the distance between cells decreased. This pattern was partly attributable to the pattern of collagen compaction. These findings are of interest because fibril alignment, density, and strain energy may each contribute to contact guidance during tissue morphogenesis.

  18. Construct - A Multi-Agent Network Model for the Co-Evolution of Agents and Socio-Cultural Environments

    DTIC Science & Technology

    2004-05-01

    expertise measures. The illustrative task assumes a knowledge base of size 50. • Baysian T-test (BaysianT.csv) This file contains values...Sufficient effort for an illustrative task size of 10 Column 18: Average number of agents • Baysian T-test (BaysianT.csv) This file contains

  19. Why Firms Change Hands.

    ERIC Educational Resources Information Center

    Felder, Joseph

    1985-01-01

    Described is the subjective process by which the minimum asking price and the maximum offer prices are determined for a firm changing hands. Insight is gained into the meaning of fixed cost, opportunity cost, profit, present value, capital gain, and comparative advantages. (Author/RM)

  20. Firms, crowds, and innovation

    PubMed Central

    Felin, Teppo; Lakhani, Karim R; Tushman, Michael L

    2017-01-01

    The purpose of this article is to suggest a (preliminary) taxonomy and research agenda for the topic of “firms, crowds, and innovation” and to provide an introduction to the associated special issue. We specifically discuss how various crowd-related phenomena and practices—for example, crowdsourcing, crowdfunding, user innovation, and peer production—relate to theories of the firm, with particular attention on “sociality” in firms and markets. We first briefly review extant theories of the firm and then discuss three theoretical aspects of sociality related to crowds in the context of strategy, organizations, and innovation: (1) the functions of sociality (sociality as extension of rationality, sociality as sensing and signaling, sociality as matching and identity), (2) the forms of sociality (independent/aggregate and interacting/emergent forms of sociality), and (3) the failures of sociality (misattribution and misapplication). We conclude with an outline of future research directions and introduce the special issue papers and essays. PMID:28690428

  1. Cumulative sum and neural network approach to the detection and identification of hazardous chemical agents from ion mobility spectra

    NASA Astrophysics Data System (ADS)

    Ruotsalainen, Marja; Vihonen, Juho; Jylhä, Juha; Kauppila, Jarmo; Anttalainen, Osmo; Visa, Ari

    2008-10-01

    The detection and identification of hazardous chemical agents are important problems in the fields of security and defense. Although the diverse environmental conditions and varying concentrations of the chemical agents make the problem challenging, the identification system should be able to give early warnings, identify the gas reliably, and operate with low false alarm rate. We have researched detection and identification of chemical agents with a swept-field aspiration condenser type ion mobility spectrometry prototype. This paper introduces an identification system, which consists of a cumulative sum algorithm (CUSUM) -based change detector and a neural network classifier. As a novelty, the use of CUSUM algorithm allows the gas identification task to be accomplished using carefully selected measurements. For the identification of hazardous agents we, as a further novelty, utilize the principal component analysis to transform the swept-field ion mobility spectra into a more compact and appropriate form. Neural networks have been found to be a reliable method for spectra categorization in the context of swept-field technology. However, the proposed spectra reduction raises the accuracy of the neural network classifier and decreases the number of neurons. Finally, we present comparison to the earlier neural network solution and demonstrate that the percentage of correctly classified sweeps can be considerably raised by using the CUSUM-based change detector.

  2. Determinants of Firm Internal Labor Markets in Large Law Firms.

    ERIC Educational Resources Information Center

    Wholey, Douglas R.

    1985-01-01

    Determinants of individual mobility within firms (promotion) and between firms (lateral entry) are developed and listed. Using data from 80 large law firms over a 3-year period, 8 hypotheses were tested by regressing number of promotions and number of lateral entries on 11 independent variables. Appended are 57 citations. (MLF)

  3. CRP for Pesticides - Testing Firms

    EPA Pesticide Factsheets

    This list includes firms that have conducted tests or have indicated an interest in conducting tests on child-resistant packaging. This list is not intended to indicate EPA approval, certification, or endorsement of these firms, nor is it comprehensive..

  4. Multi-agent modelling framework for water, energy and other resource networks

    NASA Astrophysics Data System (ADS)

    Knox, S.; Selby, P. D.; Meier, P.; Harou, J. J.; Yoon, J.; Lachaut, T.; Klassert, C. J. A.; Avisse, N.; Mohamed, K.; Tomlinson, J.; Khadem, M.; Tilmant, A.; Gorelick, S.

    2015-12-01

    Bespoke modelling tools are often needed when planning future engineered interventions in the context of various climate, socio-economic and geopolitical futures. Such tools can help improve system operating policies or assess infrastructure upgrades and their risks. A frequently used approach is to simulate and/or optimise the impact of interventions in engineered systems. Modelling complex infrastructure systems can involve incorporating multiple aspects into a single model, for example physical, economic and political. This presents the challenge of combining research from diverse areas into a single system effectively. We present the Pynsim 'Python Network Simulator' framework, a library for building simulation models capable of representing, the physical, institutional and economic aspects of an engineered resources system. Pynsim is an open source, object oriented code aiming to promote integration of different modelling processes through a single code library. We present two case studies that demonstrate important features of Pynsim's design. The first is a large interdisciplinary project of a national water system in the Middle East with modellers from fields including water resources, economics, hydrology and geography each considering different facets of a multi agent system. It includes: modelling water supply and demand for households and farms; a water tanker market with transfer of water between farms and households, and policy decisions made by government institutions at district, national and international level. This study demonstrates that a well-structured library of code can provide a hub for development and act as a catalyst for integrating models. The second focuses on optimising the location of new run-of-river hydropower plants. Using a multi-objective evolutionary algorithm, this study analyses different network configurations to identify the optimal placement of new power plants within a river network. This demonstrates that Pynsim can be

  5. A Multi-Agent Framework for Packet Routing in Wireless Sensor Networks

    PubMed Central

    Ye, Dayon; Zhang, Minji; Yang, Yu

    2015-01-01

    Wireless sensor networks (WSNs) have been widely investigated in recent years. One of the fundamental issues in WSNs is packet routing, because in many application domains, packets have to be routed from source nodes to destination nodes as soon and as energy efficiently as possible. To address this issue, a large number of routing approaches have been proposed. Although every existing routing approach has advantages, they also have some disadvantages. In this paper, a multi-agent framework is proposed that can assist existing routing approaches to improve their routing performance. This framework enables each sensor node to build a cooperative neighbour set based on past routing experience. Such cooperative neighbours, in turn, can help the sensor to effectively relay packets in the future. This framework is independent of existing routing approaches and can be used to assist many existing routing approaches. Simulation results demonstrate the good performance of this framework in terms of four metrics: average delivery latency, successful delivery ratio, number of live nodes and total sensing coverage. PMID:25928063

  6. Autonomous construction agents: An investigative framework for large sensor network self-management

    SciTech Connect

    Koch, Joshua Bruce

    2008-01-01

    Recent technological advances have made it cost effective to utilize massive, heterogeneous sensor networks. To gain appreciable value from these informational systems, there must be a control scheme that coordinates information flow to produce meaningful results. This paper will focus on tools developed to manage the coordination of autonomous construction agents using stigmergy, in which a set of basic low-level rules are implemented through various environmental cues. Using VE-Suite, an open-source virtual engineering software package, an interactive environment is created to explore various informational configurations for the construction problem. A simple test case is developed within the framework, and construction times are analyzed for possible functional relationships pertaining to performance of a particular set of parameters and a given control process. Initial experiments for the test case show sensor saturation occurs relatively quickly with 5-7 sensors, and construction time is generally independent of sensor range except for small numbers of sensors. Further experiments using this framework are needed to define other aspects of sensor performance. These trends can then be used to help decide what kinds of sensing capabilities are required to simultaneously achieve the most cost-effective solution and provide the required value of information when applied to the development of real world sensor applications.

  7. Preferences for caries prevention agents in adult patients: findings from The Dental Practice-Based Research Network

    PubMed Central

    Riley, Joseph L.; Gordan, Valeria V.; Rindal, D. Brad; Fellows, Jeffrey L.; Ajmo, Craig T.; Amundson, Craig; Anderson, Gerald A.; Gilbert, Gregg H.

    2010-01-01

    Objectives To identify factors that are significantly associated with dentists’ use of specific caries preventive agents in adult patients, and whether dentists who use one preventive agent are also more likely to use certain others. Methods Data were collected from 564 practitioners in The Dental Practice-Based Research Network, a multi-region consortium of participating practices and dental organizations. Results In-office topical fluoride was the method most frequently used. Regarding at-home preventive agents, there was little difference in preference between non-prescription fluoride, prescription fluoride, or chlorhexidine rinse. Dentists who most frequently used caries prevention were also those who regularly perform caries risk assessment and individualize caries prevention at the patient level. Higher percentages of patients with dental insurance were significantly associated with more use of in-office prevention modalities. Female dentists and dentists with more-recent training were more likely to recommend preventive agents that are applied by the patient. Dentists who reported more-conservative decisions in clinical treatment scenarios were also more likely to use caries preventive agents. Groups of dentist who shared a common preference for certain preventive agents were identified. One group used preventive agents selectively, whereas the other groups predominately used either in-office or at-home fluorides. Conclusions Caries prevention is commonly used with adult patients. However, these results suggest that only a subset of dentists base preventive treatments on caries risk at the individual patient level. PMID:20560997

  8. Preferences for caries prevention agents in adult patients: findings from the dental practice-based research network.

    PubMed

    Riley, Joseph L; Gordan, Valeria V; Rindal, D Brad; Fellows, Jeffrey L; Ajmo, Craig T; Amundson, Craig; Anderson, Gerald A; Gilbert, Gregg H

    2010-08-01

    To identify factors that are significantly associated with dentists' use of specific caries preventive agents in adult patients, and whether dentists who use one preventive agent are also more likely to use certain others. Data were collected from 564 practitioners in The Dental Practice-Based Research Network, a multi-region consortium of participating practices and dental organizations. In-office topical fluoride was the method most frequently used. Regarding at-home preventive agents, there was little difference in preference between nonprescription fluoride, prescription fluoride, or chlorhexidine rinse. Dentists who most frequently used caries prevention were also those who regularly perform caries risk assessment and individualize caries prevention at the patient level. Higher percentages of patients with dental insurance were significantly associated with more use of in-office prevention modalities. Female dentists and dentists with more-recent training were more likely to recommend preventive agents that are applied by the patient. Dentists who reported more-conservative decisions in clinical treatment scenarios were also more likely to use caries preventive agents. Groups of dentist who shared a common preference for certain preventive agents were identified. One group used preventive agents selectively, whereas the other groups predominately used either in-office or at-home fluorides. Caries prevention is commonly used with adult patients. However, these results suggest that only a subset of dentists base preventive treatments on caries risk at the individual patient level.

  9. One-step synthesis and characterization of polyaniline nanofiber/silver nanoparticle composite networks as antibacterial agents.

    PubMed

    Poyraz, Selcuk; Cerkez, Idris; Huang, Tung Shi; Liu, Zhen; Kang, Litao; Luo, Jujie; Zhang, Xinyu

    2014-11-26

    Through a facile and effective seeding polymerization reaction via a one-step redox/complexation process, which took place in aqueous medium at ambient temperature, silver nanoparticles (Ag NPs) embedded polyaniline nanofiber (PANI NF) networks were synthesized as antibacterial agents. During the reaction, not only NF morphology formation of the resulting conducting polymers (CPs) but also amplification of the aqueous silver nitrate (AgNO3) solutions' oxidative potentials were managed by vanadium pentoxide (V2O5) sol-gel nanofibers, which acted as well-known nanofibrous seeding agents and the auxiliary oxidative agent at the same time. The PANI/Ag nanocomposites were proven to exhibit excellent antibacterial property against both Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus. Antibacterial property performance and average life span of the nanocomposite network were optimized through the homogeneous distribution/embedment of Ag NPs within one-dimensional (1-D) PANI NF matrix. The antibacterial efficacy tests and nanocomposite material characterization results further indicated that the sole components of PANI/Ag have a synergistic effect to each other in terms of antibacterial property. Thus, this well-known catalytic seeding approach via a one-step oxidative polymerization reaction can be considered as a general methodology and a substantial fabrication tool to synthesize Ag NP decorated nanofibrillar PANI networks as advanced antibacterial agents.

  10. Leveraging social influence to address overweight and obesity using agent-based models: the role of adolescent social networks.

    PubMed

    Zhang, J; Tong, L; Lamberson, P J; Durazo-Arvizu, R A; Luke, A; Shoham, D A

    2015-01-01

    The prevalence of adolescent overweight and obesity (hereafter, simply "overweight") in the US has increased over the past several decades. Individually-targeted prevention and treatment strategies targeting individuals have been disappointing, leading some to propose leveraging social networks to improve interventions. We hypothesized that social network dynamics (social marginalization; homophily on body mass index, BMI) and the strength of peer influence would increase or decrease the proportion of network member (agents) becoming overweight over a simulated year, and that peer influence would operate differently in social networks with greater overweight. We built an agent-based model (ABM) using results from R-SIENA. ABMs allow for the exploration of potential interventions using simulated agents. Initial model specifications were drawn from Wave 1 of the National Longitudinal Study of Adolescent Health (Add Health). We focused on a single saturation school with complete network and BMI data over two waves (n = 624). The model was validated against empirical observations at Wave 2. We focused on overall overweight prevalence after a simulated year. Five experiments were conducted: (1) changing attractiveness of high-BMI agents; (2) changing homophily on BMI; (3) changing the strength of peer influence; (4) shifting the overall BMI distribution; and (5) targeting dietary interventions to highly connected individuals. Increasing peer influence showed a dramatic decrease in the prevalence of overweight; making peer influence negative (i.e., doing the opposite of friends) increased overweight. However, the effect of peer influence varied based on the underlying distribution of BMI; when BMI was increased overall, stronger peer influence increased proportion of overweight. Other interventions, including targeted dieting, had little impact. Peer influence may be a viable target in overweight interventions, but the distribution of body size in the population needs to

  11. Polarization and Belief Dynamics in the Black and White Communities: An Agent-Based Network Model from the Data

    PubMed Central

    Grim, Patrick; Thomas, Stephen B.; Fisher, Steven; Reade, Christopher; Singer, Daniel J.; Garza, Mary A.; Fryer, Craig S.; Chatman, Jamie

    2013-01-01

    Public health care interventions—regarding vaccination, obesity, and HIV, for example—standardly take the form of information dissemination across a community. But information networks can vary importantly between different ethnic communities, as can levels of trust in information from different sources. We use data from the Greater Pittsburgh Random Household Health Survey to construct models of information networks for White and Black communities--models which reflect the degree of information contact between individuals, with degrees of trust in information from various sources correlated with positions in that social network. With simple assumptions regarding belief change and social reinforcement, we use those modeled networks to build dynamic agent-based models of how information can be expected to flow and how beliefs can be expected to change across each community. With contrasting information from governmental and religious sources, the results show importantly different dynamic patterns of belief polarization within the two communities. PMID:25298731

  12. An Agent-based Model Simulation of Multiple Collaborating Mobile Ad Hoc Networks (MANET)

    DTIC Science & Technology

    2011-06-01

    RESULTS: Agent Learning Profiles Discounted Positive Reinforcement Learning Learning and Forgetting Forgetting is triggered by task conditions that...disable rational and deliberate mental models –forcing the agent to ignore (or forget) routine processes. Positive reinforcement is earned by an...deliberate behavior of agents as rational entities (model-based functions). 6.Experiment with positive reinforcement learning (with incremental gain over

  13. Impact of Mucolytic Agents on COPD Exacerbations: A Pair-wise and Network Meta-analysis.

    PubMed

    Cazzola, Mario; Rogliani, Paola; Calzetta, Luigino; Hanania, Nicola A; Matera, Maria Gabriella

    2017-10-01

    Mucolytics are potentially useful for the management of chronic obstructive pulmonary disease (COPD), although there is conflicting advice on their use in different guideline documents. Furthermore, there is paucity of data comparing the efficacy of the different mucolytic agents in reducing the odds of COPD exacerbations. We performed pair-wise and network meta-analyses to evaluate the impact of mucoly-tics in COPD. Randomized clinical trials lasting at least 3 months and investigating the effects of mucolytics on COPD exacerbations were identified from published studies and repository databases. Mucolytics significantly reduced the odds of exacerbation vs. placebo (11 studies analyzed: odds ratio (OR) 0.51, 95% confidence interval (CI) 0.39-0.67; p < 0.001). The most effective drugs were carbocysteine, erdosteine, and N-acetylcysteine 1,200 mg/day (SUCRA 68.0-79.0%), whereas the OR was similar to placebo for ambroxol and N-acetylcysteine 600 mg/day. Only N-acetylcysteine 1,200 mg/day significantly protected against exacerbations vs. placebo (2 studies analyzed: OR 0.56, 95% CI 0.35-0.92; p < 0.05; high quality of evidence). A signal of effectiveness was detected for carbocysteine (2 studies analyzed: OR 0.45, 95% CI 0.20-1.01; p ≥ 0.05; moderate quality of evidence). Specific differences in study designs and patient-related characteristics, such as history of exacerbations and ethnicity, were potential effect modifiers for our statistical models, whereas neither respiratory function nor the use of corticosteroids influenced the analysis. This meta-analysis demonstrates that mucolytics are useful in preventing COPD exacerbations as maintenance add-on therapy to patients with frequent exacerbations. The effectiveness of mucolytics is independent of the severity of airway obstruction and the use of inhaled corticosteroids.

  14. The Implementation, Promotion and Evaluation of the International Health Communication Hotline as a Tool for Interdisciplinary Networking and Disciplinary Advocacy.

    ERIC Educational Resources Information Center

    Assante, Leonard E.; Schrader, Stuart M.

    The International Health Communication Hotline (InHealth) represents an attempt to firmly establish, develop and promote a new Communication Studies subdiscipline in the academic and health care arenas via computer networking. If successful, the project will demonstrate the power of computer networking as an agent of change. Health communication…

  15. INTERDISCIPLINARY PHYSICS AND RELATED AREAS OF SCIENCE AND TECHNOLOGY: Consensus of Multi-Agent Systems with Prestissimo Scale-Free Networks

    NASA Astrophysics Data System (ADS)

    Yang, Hong-Yong; Lu, Lan; Cao, Ke-Cai; Zhang, Si-Ying

    2010-04-01

    In this paper, the relations of the network topology and the moving consensus of multi-agent systems are studied. A consensus-prestissimo scale-free network model with the static preferential-consensus attachment is presented on the rewired link of the regular network. The effects of the static preferential-consensus BA network on the algebraic connectivity of the topology graph are compared with the regular network. The robustness gain to delay is analyzed for variable network topology with the same scale. The time to reach the consensus is studied for the dynamic network with and without communication delays. By applying the computer simulations, it is validated that the speed of the convergence of multi-agent systems can be greatly improved in the preferential-consensus BA network model with different configuration.

  16. Enhanced Deployment Strategy for Role-based Hierarchical Application Agents in Wireless Sensor Networks with Established Clusterheads

    NASA Astrophysics Data System (ADS)

    Gendreau, Audrey

    Efficient self-organizing virtual clusterheads that supervise data collection based on their wireless connectivity, risk, and overhead costs, are an important element of Wireless Sensor Networks (WSNs). This function is especially critical during deployment when system resources are allocated to a subsequent application. In the presented research, a model used to deploy intrusion detection capability on a Local Area Network (LAN), in the literature, was extended to develop a role-based hierarchical agent deployment algorithm for a WSN. The resulting model took into consideration the monitoring capability, risk, deployment distribution cost, and monitoring cost associated with each node. Changing the original LAN methodology approach to model a cluster-based sensor network depended on the ability to duplicate a specific parameter that represented the monitoring capability. Furthermore, other parameters derived from a LAN can elevate costs and risk of deployment, as well as jeopardize the success of an application on a WSN. A key component of the approach presented in this research was to reduce the costs when established clusterheads in the network were found to be capable of hosting additional detection agents. In addition, another cost savings component of the study addressed the reduction of vulnerabilities associated with deployment of agents to high volume nodes. The effectiveness of the presented method was validated by comparing it against a type of a power-based scheme that used each node's remaining energy as the deployment value. While available energy is directly related to the model used in the presented method, the study deliberately sought out nodes that were identified with having superior monitoring capability, cost less to create and sustain, and are at low-risk of an attack. This work investigated improving the efficiency of an intrusion detection system (IDS) by using the proposed model to deploy monitoring agents after a temperature sensing

  17. Apple hypanthium firmness: new insights from comparative proteomics.

    PubMed

    Marondedze, Claudius; Thomas, Ludivine A

    2012-09-01

    Fruit firmness constitutes an important textural property and is one of the key parameters for estimating ripening and shelf life, which has a major impact on commercialization. In order to decipher the mechanisms related to firmness of apples (Malus × domestica Borkh.), two-dimensional gel electrophoresis (2-DE) was used to compare the total proteome of high and low firmness phenotypes from apple hypanthia of a 'Golden Delicious' × 'Dietrich' population. A total of 36 differentially regulated protein spots were positively identified by matrix assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrometry (MS) and then validated against the Malus expressed sequence tags (EST) database. The findings of this study indicated a lower expression of ethylene biosynthesis related proteins in the high firmness phenotype, which could be linked to the slowing down of the ripening and softening processes. The reduced accumulation of proteins involved in ethylene biosynthesis juxtaposed to the upregulation of a transposase and a GTP-binding protein in the high firmness phenotype. The results also showed higher expression of cytoskeleton proteins in the high firmness phenotype compared to the low firmness phenotype, which play a role in maintaining cell structure and possibly fruit integrity. Finally, a number of proteins involved in detoxification and defense were expressed in fruit hypanthium. This proteomic study provides a contribution towards a better understanding of regulatory networks involved in fruit hypanthium firmness and/or softening, which could be instrumental in the development of improved fruit quality.

  18. Distributed H∞ control of multi-agent systems with directed networks

    NASA Astrophysics Data System (ADS)

    Liu, Wei; Liu, Ai-Li; Zhou, Shao-Lei

    2015-09-01

    This paper studies the distributed H∞ control problem of identical linear time invariant multi-agent systems subject to external disturbances. A directed graph containing a spanning tree is used to model the communication topology. Based on the relative states of the neighbor agents and a subset of absolute states of the agents, distributed static H∞ controllers are proposed. The concept of an H∞ performance region is extended to the directed graph situation. Then the results are used to solve the leader-follower H∞ consensus problem. Sufficient conditions are proposed based on bounded real lemma and algebraic graph theory. The effectiveness of the theoretical results is illustrated via numerical simulations.

  19. Bayesian networks and agent-based modeling approach for urban land-use and population density change: a BNAS model

    NASA Astrophysics Data System (ADS)

    Kocabas, Verda; Dragicevic, Suzana

    2013-10-01

    Land-use change models grounded in complexity theory such as agent-based models (ABMs) are increasingly being used to examine evolving urban systems. The objective of this study is to develop a spatial model that simulates land-use change under the influence of human land-use choice behavior. This is achieved by integrating the key physical and social drivers of land-use change using Bayesian networks (BNs) coupled with agent-based modeling. The BNAS model, integrated Bayesian network-based agent system, presented in this study uses geographic information systems, ABMs, BNs, and influence diagram principles to model population change on an irregular spatial structure. The model is parameterized with historical data and then used to simulate 20 years of future population and land-use change for the City of Surrey, British Columbia, Canada. The simulation results identify feasible new urban areas for development around the main transportation corridors. The obtained new development areas and the projected population trajectories with the“what-if” scenario capabilities can provide insights into urban planners for better and more informed land-use policy or decision-making processes.

  20. Agent-based spin model for financial markets on complex networks: Emergence of two-phase phenomena

    NASA Astrophysics Data System (ADS)

    Kim, Yup; Kim, Hong-Joo; Yook, Soon-Hyung

    2008-09-01

    We study a microscopic model for financial markets on complex networks, motivated by the dynamics of agents and their structure of interaction. The model consists of interacting agents (spins) with local ferromagnetic coupling and global antiferromagnetic coupling. In order to incorporate more realistic situations, we also introduce an external field which changes in time. From numerical simulations, we find that the model shows two-phase phenomena. When the local ferromagnetic interaction is balanced with the global antiferromagnetic interaction, the resulting return distribution satisfies a power law having a single peak at zero values of return, which corresponds to the market equilibrium phase. On the other hand, if local ferromagnetic interaction is dominant, then the return distribution becomes double peaked at nonzero values of return, which characterizes the out-of-equilibrium phase. On random networks, the crossover between two phases comes from the competition between two different interactions. However, on scale-free networks, not only the competition between the different interactions but also the heterogeneity of underlying topology causes the two-phase phenomena. Possible relationships between the critical phenomena of spin system and the two-phase phenomena are discussed.

  1. An Intelligent Agent Approach for Teaching Neural Networks Using LEGO[R] Handy Board Robots

    ERIC Educational Resources Information Center

    Imberman, Susan P.

    2004-01-01

    In this article we describe a project for an undergraduate artificial intelligence class. The project teaches neural networks using LEGO[R] handy board robots. Students construct robots with two motors and two photosensors. Photosensors provide readings that act as inputs for the neural network. Output values power the motors and maintain the…

  2. An Intelligent Agent Approach for Teaching Neural Networks Using LEGO[R] Handy Board Robots

    ERIC Educational Resources Information Center

    Imberman, Susan P.

    2004-01-01

    In this article we describe a project for an undergraduate artificial intelligence class. The project teaches neural networks using LEGO[R] handy board robots. Students construct robots with two motors and two photosensors. Photosensors provide readings that act as inputs for the neural network. Output values power the motors and maintain the…

  3. Skills Gaps in Australian Firms

    ERIC Educational Resources Information Center

    Lindorff, Margaret

    2011-01-01

    This paper reports the results of a survey of more than 2000 managers examining perceptions of skills gaps in a range of Australian firms. It finds that three quarters report a skills gap, and almost one third report skills gaps across the whole organisation. Firm size and industry differences exist in perceptions of the effect of the skills gap…

  4. Skills Gaps in Australian Firms

    ERIC Educational Resources Information Center

    Lindorff, Margaret

    2011-01-01

    This paper reports the results of a survey of more than 2000 managers examining perceptions of skills gaps in a range of Australian firms. It finds that three quarters report a skills gap, and almost one third report skills gaps across the whole organisation. Firm size and industry differences exist in perceptions of the effect of the skills gap…

  5. Semantic network mapping of religious material: testing multi-agent computer models of social theories against real-world data.

    PubMed

    Lane, Justin E

    2015-11-01

    Agent-based modeling allows researchers to investigate theories of complex social phenomena and subsequently use the model to generate new hypotheses that can then be compared to real-world data. However, computer modeling has been underutilized in regard to the understanding of religious systems, which often require very complex theories with multiple interacting variables (Braxton et al. in Method Theory Study Relig 24(3):267-290, 2012. doi: 10.1163/157006812X635709 ; Lane in J Cogn Sci Relig 1(2):161-180, 2013). This paper presents an example of how computer modeling can be used to explore, test, and further understand religious systems, specifically looking at one prominent theory of religious ritual. The process is continuous: theory building, hypothesis generation, testing against real-world data, and improving the model. In this example, the output of an agent-based model of religious behavior is compared against real-world religious sermons and texts using semantic network analysis. It finds that most religious materials exhibit unique scale-free small-world properties and that a concept's centrality in a religious schema best predicts its frequency of presentation. These results reveal that there adjustments need to be made to existing models of religious ritual systems and provide parameters for future models. The paper ends with a discussion of implications for a new multi-agent model of doctrinal ritual behaviors as well as propositions for further interdisciplinary research concerning the multi-agent modeling of religious ritual behaviors.

  6. Production, depreciation and the size distribution of firms

    NASA Astrophysics Data System (ADS)

    Ma, Qi; Chen, Yongwang; Tong, Hui; Di, Zengru

    2008-05-01

    Many empirical researches indicate that firm size distributions in different industries or countries exhibit some similar characters. Among them the fact that many firm size distributions obey power-law especially for the upper end has been mostly discussed. Here we present an agent-based model to describe the evolution of manufacturing firms. Some basic economic behaviors are taken into account, which are production with decreasing marginal returns, preferential allocation of investments, and stochastic depreciation. The model gives a steady size distribution of firms which obey power-law. The effect of parameters on the power exponent is analyzed. The theoretical results are given based on both the Fokker-Planck equation and the Kesten process. They are well consistent with the numerical results.

  7. Networks as Agents of Innovation: Teacher Networking in the Context of Vocational and Professional Higher Education Reforms

    ERIC Educational Resources Information Center

    Tafel-Viia, Külliki; Loogma, Krista; Lassur, Silja; Roosipõld, Anne

    2012-01-01

    The effective implementation of educational reform is an issue that confronts both those that plan and sponsor those reforms and those that are affected by them. This article discusses networking processes in the context of reform in vocational and professional higher education. When exploring failures in educational change processes, issues…

  8. Charting epilepsy by searching for intelligence in network space with the help of evolving autonomous agents.

    PubMed

    Ohayon, Elan L; Kalitzin, Stiliyan; Suffczynski, Piotr; Jin, Frank Y; Tsang, Paul W; Borrett, Donald S; Burnham, W McIntyre; Kwan, Hon C

    2004-01-01

    The problem of demarcating neural network space is formidable. A simple fully connected recurrent network of five units (binary activations, synaptic weight resolution of 10) has 3.2 *10(26) possible initial states. The problem increases drastically with scaling. Here we consider three complementary approaches to help direct the exploration to distinguish epileptic from healthy networks. [1] First, we perform a gross mapping of the space of five-unit continuous recurrent networks using randomized weights and initial activations. The majority of weight patterns (>70%) were found to result in neural assemblies exhibiting periodic limit-cycle oscillatory behavior. [2] Next we examine the activation space of non-periodic networks demonstrating that the emergence of paroxysmal activity does not require changes in connectivity. [3] The next challenge is to focus the search of network space to identify networks with more complex dynamics. Here we rely on a major available indicator critical to clinical assessment but largely ignored by epilepsy modelers, namely: behavioral states. To this end, we connected the above network layout to an external robot in which interactive states were evolved. The first random generation showed a distribution in line with approach [1]. That is, the predominate phenotypes were fixed-point or oscillatory with seizure-like motor output. As evolution progressed the profile changed markedly. Within 20 generations the entire population was able to navigate a simple environment with all individuals exhibiting multiply-stable behaviors with no cases of default locked limit-cycle oscillatory motor behavior. The resultant population may thus afford us a view of the architectural principles demarcating healthy biological networks from the pathological. The approach has an advantage over other epilepsy modeling techniques in providing a way to clarify whether observed dynamics or suggested therapies are pointing to computational viability or dead

  9. Self-Organized Link State Aware Routing for Multiple Mobile Agents in Wireless Network

    NASA Astrophysics Data System (ADS)

    Oda, Akihiro; Nishi, Hiroaki

    Recently, the importance of data sharing structures in autonomous distributed networks has been increasing. A wireless sensor network is used for managing distributed data. This type of distributed network requires effective information exchanging methods for data sharing. To reduce the traffic of broadcasted messages, reduction of the amount of redundant information is indispensable. In order to reduce packet loss in mobile ad-hoc networks, QoS-sensitive routing algorithm have been frequently discussed. The topology of a wireless network is likely to change frequently according to the movement of mobile nodes, radio disturbance, or fading due to the continuous changes in the environment. Therefore, a packet routing algorithm should guarantee QoS by using some quality indicators of the wireless network. In this paper, a novel information exchanging algorithm developed using a hash function and a Boolean operation is proposed. This algorithm achieves efficient information exchanges by reducing the overhead of broadcasting messages, and it can guarantee QoS in a wireless network environment. It can be applied to a routing algorithm in a mobile ad-hoc network. In the proposed routing algorithm, a routing table is constructed by using the received signal strength indicator (RSSI), and the neighborhood information is periodically broadcasted depending on this table. The proposed hash-based routing entry management by using an extended MAC address can eliminate the overhead of message flooding. An analysis of the collision of hash values contributes to the determination of the length of the hash values, which is minimally required. Based on the verification of a mathematical theory, an optimum hash function for determining the length of hash values can be given. Simulations are carried out to evaluate the effectiveness of the proposed algorithm and to validate the theory in a general wireless network routing algorithm.

  10. A junction-tree based learning algorithm to optimize network wide traffic control: A coordinated multi-agent framework

    SciTech Connect

    Zhu, Feng; Aziz, H. M. Abdul; Qian, Xinwu; Ukkusuri, Satish V.

    2015-01-31

    Our study develops a novel reinforcement learning algorithm for the challenging coordinated signal control problem. Traffic signals are modeled as intelligent agents interacting with the stochastic traffic environment. The model is built on the framework of coordinated reinforcement learning. The Junction Tree Algorithm (JTA) based reinforcement learning is proposed to obtain an exact inference of the best joint actions for all the coordinated intersections. Moreover, the algorithm is implemented and tested with a network containing 18 signalized intersections in VISSIM. Finally, our results show that the JTA based algorithm outperforms independent learning (Q-learning), real-time adaptive learning, and fixed timing plans in terms of average delay, number of stops, and vehicular emissions at the network level.

  11. A junction-tree based learning algorithm to optimize network wide traffic control: A coordinated multi-agent framework

    DOE PAGES

    Zhu, Feng; Aziz, H. M. Abdul; Qian, Xinwu; ...

    2015-01-31

    Our study develops a novel reinforcement learning algorithm for the challenging coordinated signal control problem. Traffic signals are modeled as intelligent agents interacting with the stochastic traffic environment. The model is built on the framework of coordinated reinforcement learning. The Junction Tree Algorithm (JTA) based reinforcement learning is proposed to obtain an exact inference of the best joint actions for all the coordinated intersections. Moreover, the algorithm is implemented and tested with a network containing 18 signalized intersections in VISSIM. Finally, our results show that the JTA based algorithm outperforms independent learning (Q-learning), real-time adaptive learning, and fixed timing plansmore » in terms of average delay, number of stops, and vehicular emissions at the network level.« less

  12. Understanding Group/Party Affiliation Using Social Networks and Agent-Based Modeling

    NASA Technical Reports Server (NTRS)

    Campbell, Kenyth

    2012-01-01

    The dynamics of group affiliation and group dispersion is a concept that is most often studied in order for political candidates to better understand the most efficient way to conduct their campaigns. While political campaigning in the United States is a very hot topic that most politicians analyze and study, the concept of group/party affiliation presents its own area of study that producers very interesting results. One tool for examining party affiliation on a large scale is agent-based modeling (ABM), a paradigm in the modeling and simulation (M&S) field perfectly suited for aggregating individual behaviors to observe large swaths of a population. For this study agent based modeling was used in order to look at a community of agents and determine what factors can affect the group/party affiliation patterns that are present. In the agent-based model that was used for this experiment many factors were present but two main factors were used to determine the results. The results of this study show that it is possible to use agent-based modeling to explore group/party affiliation and construct a model that can mimic real world events. More importantly, the model in the study allows for the results found in a smaller community to be translated into larger experiments to determine if the results will remain present on a much larger scale.

  13. A Spawn Mobile Agent Itinerary Planning Approach for Energy-Efficient Data Gathering in Wireless Sensor Networks

    PubMed Central

    Qadori, Huthiafa Q.; Zulkarnain, Zuriati A.; Hanapi, Zurina Mohd; Subramaniam, Shamala

    2017-01-01

    Mobile agent (MA), a part of the mobile computing paradigm, was recently proposed for data gathering in Wireless Sensor Networks (WSNs). The MA-based approach employs two algorithms: Single-agent Itinerary Planning (SIP) and Multi-mobile agent Itinerary Planning (MIP) for energy-efficient data gathering. The MIP was proposed to outperform the weakness of SIP by introducing distributed multi MAs to perform the data gathering task. Despite the advantages of MIP, finding the optimal number of distributed MAs and their itineraries are still regarded as critical issues. The existing MIP algorithms assume that the itinerary of the MA has to start and return back to the sink node. Moreover, each distributed MA has to carry the processing code (data aggregation code) to collect the sensory data and return back to the sink with the accumulated data. However, these assumptions have resulted in an increase in the number of MA’s migration hops, which subsequently leads to an increase in energy and time consumption. In this paper, a spawn multi-mobile agent itinerary planning (SMIP) approach is proposed to mitigate the substantial increase in cost of energy and time used in the data gathering processes. The proposed approach is based on the agent spawning such that the main MA is able to spawn other MAs with different tasks assigned from the main MA. Extensive simulation experiments have been conducted to test the performance of the proposed approach against some selected MIP algorithms. The results show that the proposed SMIP outperforms the counterpart algorithms in terms of energy consumption and task delay (time), and improves the integrated energy-delay performance. PMID:28587187

  14. A Spawn Mobile Agent Itinerary Planning Approach for Energy-Efficient Data Gathering in Wireless Sensor Networks.

    PubMed

    Qadori, Huthiafa Q; Zulkarnain, Zuriati A; Hanapi, Zurina Mohd; Subramaniam, Shamala

    2017-06-03

    Mobile agent (MA), a part of the mobile computing paradigm, was recently proposed for data gathering in Wireless Sensor Networks (WSNs). The MA-based approach employs two algorithms: Single-agent Itinerary Planning (SIP) and Multi-mobile agent Itinerary Planning (MIP) for energy-efficient data gathering. The MIP was proposed to outperform the weakness of SIP by introducing distributed multi MAs to perform the data gathering task. Despite the advantages of MIP, finding the optimal number of distributed MAs and their itineraries are still regarded as critical issues. The existing MIP algorithms assume that the itinerary of the MA has to start and return back to the sink node. Moreover, each distributed MA has to carry the processing code (data aggregation code) to collect the sensory data and return back to the sink with the accumulated data. However, these assumptions have resulted in an increase in the number of MA's migration hops, which subsequently leads to an increase in energy and time consumption. In this paper, a spawn multi-mobile agent itinerary planning (SMIP) approach is proposed to mitigate the substantial increase in cost of energy and time used in the data gathering processes. The proposed approach is based on the agent spawning such that the main MA is able to spawn other MAs with different tasks assigned from the main MA. Extensive simulation experiments have been conducted to test the performance of the proposed approach against some selected MIP algorithms. The results show that the proposed SMIP outperforms the counterpart algorithms in terms of energy consumption and task delay (time), and improves the integrated energy-delay performance.

  15. Modeling the Internet of Things, Self-Organizing and Other Complex Adaptive Communication Networks: A Cognitive Agent-Based Computing Approach

    PubMed Central

    2016-01-01

    Background Computer Networks have a tendency to grow at an unprecedented scale. Modern networks involve not only computers but also a wide variety of other interconnected devices ranging from mobile phones to other household items fitted with sensors. This vision of the "Internet of Things" (IoT) implies an inherent difficulty in modeling problems. Purpose It is practically impossible to implement and test all scenarios for large-scale and complex adaptive communication networks as part of Complex Adaptive Communication Networks and Environments (CACOONS). The goal of this study is to explore the use of Agent-based Modeling as part of the Cognitive Agent-based Computing (CABC) framework to model a Complex communication network problem. Method We use Exploratory Agent-based Modeling (EABM), as part of the CABC framework, to develop an autonomous multi-agent architecture for managing carbon footprint in a corporate network. To evaluate the application of complexity in practical scenarios, we have also introduced a company-defined computer usage policy. Results The conducted experiments demonstrated two important results: Primarily CABC-based modeling approach such as using Agent-based Modeling can be an effective approach to modeling complex problems in the domain of IoT. Secondly, the specific problem of managing the Carbon footprint can be solved using a multiagent system approach. PMID:26812235

  16. Modeling the Internet of Things, Self-Organizing and Other Complex Adaptive Communication Networks: A Cognitive Agent-Based Computing Approach.

    PubMed

    Laghari, Samreen; Niazi, Muaz A

    2016-01-01

    Computer Networks have a tendency to grow at an unprecedented scale. Modern networks involve not only computers but also a wide variety of other interconnected devices ranging from mobile phones to other household items fitted with sensors. This vision of the "Internet of Things" (IoT) implies an inherent difficulty in modeling problems. It is practically impossible to implement and test all scenarios for large-scale and complex adaptive communication networks as part of Complex Adaptive Communication Networks and Environments (CACOONS). The goal of this study is to explore the use of Agent-based Modeling as part of the Cognitive Agent-based Computing (CABC) framework to model a Complex communication network problem. We use Exploratory Agent-based Modeling (EABM), as part of the CABC framework, to develop an autonomous multi-agent architecture for managing carbon footprint in a corporate network. To evaluate the application of complexity in practical scenarios, we have also introduced a company-defined computer usage policy. The conducted experiments demonstrated two important results: Primarily CABC-based modeling approach such as using Agent-based Modeling can be an effective approach to modeling complex problems in the domain of IoT. Secondly, the specific problem of managing the Carbon footprint can be solved using a multiagent system approach.

  17. Social Facilitation Effects by Pedagogical Conversational Agent: Lexical Network Analysis in an Online Explanation Task

    ERIC Educational Resources Information Center

    Hayashi, Yugo

    2015-01-01

    The present study investigates web-based learning activities of undergraduate students who generate explanations about a key concept taught in a large-scale classroom. The present study used an online system with Pedagogical Conversational Agent (PCA), asked to explain about the key concept from different points and provided suggestions and…

  18. Specialization and herding behavior of trading firms in a financial market

    NASA Astrophysics Data System (ADS)

    Lillo, Fabrizio; Moro, Esteban; Vaglica, Gabriella; Mantegna, Rosario N.

    2008-04-01

    Agent-based models of financial markets usually make assumptions about agent's preferred stylized strategies. Empirical validations of these assumptions have not been performed so far on a full-market scale. Here we present a comprehensive study of the resulting strategies followed by the firms which are members of the Spanish Stock Exchange. We are able to show that they can be characterized by a resulting strategy and classified in three well-defined groups of firms. Firms of the first group have a change of inventory of the traded stock which is positively correlated with the synchronous stock return whereas firms of the second group show a negative correlation. Firms of the third group have an inventory variation uncorrelated with stock return. Firms tend to stay in the same group over the years indicating a long term specialization in the strategies controlling their inventory variation. We detect a clear asymmetry in the Granger causality between inventory variation of firms and stock return. We also detect herding in the buying and selling activity of firms. The herding properties of the two groups are markedly different and consistently observed over a four-year period of trading. Firms of the second group herd much more frequently than the ones of the first group. Our results can be used as an empirical basis for agent-based models of financial markets.

  19. Control of sevoflurane anesthetic agent via neural network using electroencephalogram signals during anesthesia.

    PubMed

    Tosun, Mustafa; Ferikoğlu, Abdullah; Güntürkün, Rüştü; Unal, Cevat

    2012-04-01

    In this study, power spectrum of the EEG data and the heartbeat data obtained from 250 patients has been applied to the designed Neural network system. A backpropagation artificial neural network has been developed which contains 53 nodes in the input layer, 27 nodes in the hidden and 1 node in the output layer. In the artificial neural network inputs, the power spectral density values corresponding 1-50 Hz frequency interval of the EEG slices which has 10 seconds of time interval, the ratio of the total of the PSD values of current EEG slice to the total PSD values of EEG slice of pre-anesthesia, the ratio of the total PSD values of the EEG data to the total PSD values of the previous EEG data, and the previous anaesthetic gas ratio values have been applied and the network has been educated. The designed neural network system has been tested by using 10 data set obtained from 4 different patients. In the anesthetic gas prediction according to the anesthesia level, successful results have been obtained with the designed system. The system has been able to correctly purposeful responses in average accuracy of 94% of the cases. This method is also computationally fast and acceptable real-time clinical performance has been obtained.

  20. Successful strategies for competing networks

    NASA Astrophysics Data System (ADS)

    Aguirre, J.; Papo, D.; Buldú, J. M.

    2013-04-01

    Competitive interactions represent one of the driving forces behind evolution and natural selection in biological and sociological systems. For example, animals in an ecosystem may vie for food or mates; in a market economy, firms may compete over the same group of customers; sensory stimuli may compete for limited neural resources to enter the focus of attention. Here, we derive rules based on the spectral properties of the network governing the competitive interactions between groups of agents organized in networks. In the scenario studied here the winner of the competition, and the time needed to prevail, essentially depend on the way a given network connects to its competitors and on its internal structure. Our results allow assessment of the extent to which real networks optimize the outcome of their interaction, but also provide strategies through which competing networks can improve on their situation. The proposed approach is applicable to a wide range of systems that can be modelled as networks.

  1. Efficient Delivery of Investigational Antibacterial Agents via Sustainable Clinical Trial Networks

    PubMed Central

    McDonnell, Anthony; Rex, John H.; Goossens, Herman; Bonten, Marc; Fowler, Vance G.; Dane, Aaron

    2016-01-01

    The economics of antibiotics can be improved by infectious diseases–specific clinical trial networks. While developers would still need to implement an independent phase 1 program as well as studies focused on highly resistant pathogens, standardized procedures in a network focused on usual drug resistance phenotype isolates would permit sharing of controls and would predictably generate high-quality pivotal data for product registration while creating cost and time savings in the range of 30%–40%. This would reduce economic barriers to antibiotic development and contribute to public health. PMID:27481955

  2. Consensus seeking in a network of discrete-time linear agents with communication noises

    NASA Astrophysics Data System (ADS)

    Wang, Yunpeng; Cheng, Long; Hou, Zeng-Guang; Tan, Min; Zhou, Chao; Wang, Ming

    2015-07-01

    This paper studies the mean square consensus of discrete-time linear time-invariant multi-agent systems with communication noises. A distributed consensus protocol, which is composed of the agent's own state feedback and the relative states between the agent and its neighbours, is proposed. A time-varying consensus gain a[k] is applied to attenuate the effect of noises which inherits in the inaccurate measurement of relative states with neighbours. A polynomial, namely 'parameter polynomial', is constructed. And its coefficients are the parameters in the feedback gain vector of the proposed protocol. It turns out that the parameter polynomial plays an important role in guaranteeing the consensus of linear multi-agent systems. By the proposed protocol, necessary and sufficient conditions for mean square consensus are presented under different topology conditions: (1) if the communication topology graph has a spanning tree and every node in the graph has at least one parent node, then the mean square consensus can be achieved if and only if ∑∞k = 0a[k] = ∞, ∑∞k = 0a2[k] < ∞ and all roots of the parameter polynomial are in the unit circle; (2) if the communication topology graph has a spanning tree and there exits one node without any parent node (the leader-follower case), then the mean square consensus can be achieved if and only if ∑∞k = 0a[k] = ∞, limk → ∞a[k] = 0 and all roots of the parameter polynomial are in the unit circle; (3) if the communication topology graph does not have a spanning tree, then the mean square consensus can never be achieved. Finally, one simulation example on the multiple aircrafts system is provided to validate the theoretical analysis.

  3. HURON (HUman and Robotic Optimization Network) Multi-Agent Temporal Activity Planner/Scheduler

    NASA Technical Reports Server (NTRS)

    Hua, Hook; Mrozinski, Joseph J.; Elfes, Alberto; Adumitroaie, Virgil; Shelton, Kacie E.; Smith, Jeffrey H.; Lincoln, William P.; Weisbin, Charles R.

    2012-01-01

    HURON solves the problem of how to optimize a plan and schedule for assigning multiple agents to a temporal sequence of actions (e.g., science tasks). Developed as a generic planning and scheduling tool, HURON has been used to optimize space mission surface operations. The tool has also been used to analyze lunar architectures for a variety of surface operational scenarios in order to maximize return on investment and productivity. These scenarios include numerous science activities performed by a diverse set of agents: humans, teleoperated rovers, and autonomous rovers. Once given a set of agents, activities, resources, resource constraints, temporal constraints, and de pendencies, HURON computes an optimal schedule that meets a specified goal (e.g., maximum productivity or minimum time), subject to the constraints. HURON performs planning and scheduling optimization as a graph search in state-space with forward progression. Each node in the graph contains a state instance. Starting with the initial node, a graph is automatically constructed with new successive nodes of each new state to explore. The optimization uses a set of pre-conditions and post-conditions to create the children states. The Python language was adopted to not only enable more agile development, but to also allow the domain experts to easily define their optimization models. A graphical user interface was also developed to facilitate real-time search information feedback and interaction by the operator in the search optimization process. The HURON package has many potential uses in the fields of Operations Research and Management Science where this technology applies to many commercial domains requiring optimization to reduce costs. For example, optimizing a fleet of transportation truck routes, aircraft flight scheduling, and other route-planning scenarios involving multiple agent task optimization would all benefit by using HURON.

  4. Parents As Change Agents: Overview of the Arizona Department of Education, Parent Information Network.

    ERIC Educational Resources Information Center

    Raabe, Becky

    The Parent Information Network (PIN) is an initiative of the Arizona Department of Education to involve families of special education students. Led by parents of children with special needs, PIN provides information and technical assistance to families and educators throughout the state. The primary role is to facilitate the volunteer steering…

  5. Distributed Agent-Based Networks in Support of Advanced Marine Corps Command and Control Concept

    DTIC Science & Technology

    2012-09-01

    RSSI/Signal Correlation/SNR, etc.) Conditions of Interest such as these are representative of a semantic model that both human and computer operators...47  2.  Semantic Information Models and Valued Information at the Right Time (VIRT...concept (From Hayes-Roth 2006) ... 50  Figure 23.  An 8th Layer network management semantic object model (From Oros 2007

  6. Virtual Learning Environments as Sociomaterial Agents in the Network of Teaching Practice

    ERIC Educational Resources Information Center

    Johannesen, Monica; Erstad, Ola; Habib, Laurence

    2012-01-01

    This article presents findings related to the sociomaterial agency of educators and their practice in Norwegian education. Using actor-network theory, we ask how Virtual Learning Environments (VLEs) negotiate the agency of educators and how they shape their teaching practice. Since the same kinds of VLE tools have been widely implemented…

  7. Effect of Ductile Agents on the Dynamic Behavior of SiC3D Network Composites

    NASA Astrophysics Data System (ADS)

    Zhu, Jingbo; Wang, Yangwei; Wang, Fuchi; Fan, Qunbo

    2016-10-01

    Co-continuous SiC ceramic composites using pure aluminum, epoxy, and polyurethane (PU) as ductile agents were developed. The dynamic mechanical behavior and failure mechanisms were investigated experimentally using the split Hopkinson pressure bar (SHPB) method and computationally by finite element (FE) simulations. The results show that the SiC3D/Al composite has the best overall performance in comparison with SiC3D/epoxy and SiC3D/PU composites. FE simulations are generally consistent with experimental data. These simulations provide valuable help in predicting mechanical strength and in interpreting the experimental results and failure mechanisms. They may be combined with micrographs for fracture characterizations of the composites. We found that interactions between the SiC phase and ductile agents under dynamic compression in the SHPB method are complex, and that interfacial condition is an important parameter that determines the mechanical response of SiC3D composites with a characteristic interlocking structure during dynamic compression. However, the effect of the mechanical properties of ductile agents on dynamic behavior of the composites is a second consideration in the production of the composites.

  8. PROFITABILITY AND SIZE OF FIRM.

    DTIC Science & Technology

    Contents: The profit ratio as a measure of the relative ability of firms to expand; the profit dratio as a measure of efficiency; other uses of the... profit ratio; earlier studies using the profit ratio; valid conclusions of earlier studies; assets vs. net worth; methodology of this study...distribution of post-tax profit ratex; effect of taxes on the relative ability to expand; relative profitability of income firms; variability of profit rates

  9. POLARIS: Agent-Based Modeling Framework Development and Implementation for Integrated Travel Demand and Network and Operations Simulations

    SciTech Connect

    Auld, Joshua; Hope, Michael; Ley, Hubert; Sokolov, Vadim; Xu, Bo; Zhang, Kuilin

    2016-03-01

    This paper discusses the development of an agent-based modelling software development kit, and the implementation and validation of a model using it that integrates dynamic simulation of travel demand, network supply and network operations. A description is given of the core utilities in the kit: a parallel discrete event engine, interprocess exchange engine, and memory allocator, as well as a number of ancillary utilities: visualization library, database IO library, and scenario manager. The overall framework emphasizes the design goals of: generality, code agility, and high performance. This framework allows the modeling of several aspects of transportation system that are typically done with separate stand-alone software applications, in a high-performance and extensible manner. The issue of integrating such models as dynamic traffic assignment and disaggregate demand models has been a long standing issue for transportation modelers. The integrated approach shows a possible way to resolve this difficulty. The simulation model built from the POLARIS framework is a single, shared-memory process for handling all aspects of the integrated urban simulation. The resulting gains in computational efficiency and performance allow planning models to be extended to include previously separate aspects of the urban system, enhancing the utility of such models from the planning perspective. Initial tests with case studies involving traffic management center impacts on various network events such as accidents, congestion and weather events, show the potential of the system.

  10. Fast revelation of the motif mode for a yeast protein interaction network through intelligent agent-based distributed computing.

    PubMed

    Lee, Wei-Po; Tzou, Wen-Shyong

    2010-09-01

    In the yeast protein-protein interaction network, motif mode, a collection of motifs of special combinations of protein nodes annotated by the molecular function terms of the Gene Ontology, has revealed differences in the conservation constraints within the same topology. In this study, by employing an intelligent agent-based distributed computing method, we are able to discover motif modes in a fast and adaptive manner. Moreover, by focusing on the highly evolutionarily conserved motif modes belonging to the same biological function, we find a large downshift in the distance between nodes belonging to the same motif mode compared with the whole, suggesting that nodes with the same motif mode tend to congregate in a network. Several motif modes with a high conservation of the motif constituents were revealed, but from a new perspective, including that with a three-node motif mode engaged in the protein fate and that with three four-node motif modes involved in the genome maintenance, cellular organization, and transcription. The network motif modes discovered from this method can be linked to the wealth of biological data which require further elucidation with regard to biological functions.

  11. GRAIL: A multi-agent neural network system for gene identification

    SciTech Connect

    Xu, Y.; Mural, R.J.; Einstein, J.R.; Shah, M.B.; Uberbacher, E.C.

    1996-10-01

    Identifying genes within large regions of uncharacterized DNA is a difficult undertaking and is currently the focus of many research efforts. The authors describe a gene localization and modeling system, called GRAIL. GRAIL is a multiple sensor-neural network-based system. It localizes genes in anonymous DNA sequence by recognizing features related to protein-coding regions and the boundaries of coding regions, and then combines the recognized features using a neural network system. Localized coding regions are then optimally parsed into a gene model. Through years of extensive testing, GRAIL consistently localizes about 90% of coding portions of test genes with a false positive rate of about 10%. A number of genes for major genetic diseases have been located through the use of GRAIL, and over 1,000 research laboratories worldwide use GRAIL on regular bases for localization of genes on their newly sequenced DNA.

  12. The loss of efficiency caused by agents' uncoordinated routing in transport networks.

    PubMed

    Xu, Zhongzhi; Sun, Li; Wang, Junjie; Wang, Pu

    2014-01-01

    Large-scale daily commuting data were combined with detailed geographical information system (GIS) data to analyze the loss of transport efficiency caused by drivers' uncoordinated routing in urban road networks. We used Price of Anarchy (POA) to quantify the loss of transport efficiency and found that both volume and distribution of human mobility demand determine the POA. In order to reduce POA, a small number of highways require considerable decreases in traffic, and their neighboring arterial roads need to attract more traffic. The magnitude of the adjustment in traffic flow can be estimated using the fundamental measure traffic flow only, which is widely available and easy to collect. Surprisingly, the most congested roads or the roads with largest traffic flow were not those requiring the most reduction of traffic. This study can offer guidance for the optimal control of urban traffic and facilitate improvements in the efficiency of transport networks.

  13. A stochastic agent-based model of pathogen propagation in dynamic multi-relational social networks

    PubMed Central

    Khan, Bilal; Dombrowski, Kirk; Saad, Mohamed

    2015-01-01

    We describe a general framework for modeling and stochastic simulation of epidemics in realistic dynamic social networks, which incorporates heterogeneity in the types of individuals, types of interconnecting risk-bearing relationships, and types of pathogens transmitted across them. Dynamism is supported through arrival and departure processes, continuous restructuring of risk relationships, and changes to pathogen infectiousness, as mandated by natural history; dynamism is regulated through constraints on the local agency of individual nodes and their risk behaviors, while simulation trajectories are validated using system-wide metrics. To illustrate its utility, we present a case study that applies the proposed framework towards a simulation of HIV in artificial networks of intravenous drug users (IDUs) modeled using data collected in the Social Factors for HIV Risk survey. PMID:25859056

  14. TANDEM: A Trust-Based Agent Framework for Networked Decision Making

    DTIC Science & Technology

    2015-09-10

    In the C2 research community, Alberts et al. (2010) propose C2 Maturity Model in order to understand how organizations perform in complex networked...USA 2 Computational & Information Sciences Directorate (CISD), U.S. Army Research Laboratory (USARL), Powder Mill Rd, 20783, Adelphi, MD 2800, USA 123...Introduction Understanding what makes a team successful is a topic of ongoing research in social sciences. Individual characteristics of the team members have

  15. Total-order multi-agent task-network planning for contract bridge

    SciTech Connect

    Smith, S.J.J.; Nau, D.S.; Throop, T.A.

    1996-12-31

    This paper describes the results of applying a modified version of hierarchical task-network (HTN) planning to the problem of declarer play in contract bridge. We represent information about bridge in a task network that is extended to represent multi-agency and uncertainty. Our game-playing procedure uses this task network to generate game trees in which the set of alternative choices is determined not by the set of possible actions, but by the set of available tactical and strategic schemes. This approach avoids the difficulties that traditional game-tree search techniques have with imperfect-information games such as bridge--but it also differs in several significant ways from the planning techniques used in typical HTN planners. We describe why these modifications were needed in order to build a successful planner for bridge. This same modified HTN planning strategy appears to be useful in a variety of application domains, for example, we have used the same planning techniques in a process-planning system for the manufacture of complex electromechanical devices. We discuss why the same technique has been successful in two such diverse domains.

  16. Adaptive task-space synchronisation of networked robotic agents without task-space velocity measurements

    NASA Astrophysics Data System (ADS)

    Wang, Lijiao; Meng, Bin; Wang, Hanlei

    2014-02-01

    In this paper, we investigate the problem of task-space synchronisation of multiple robotic agents in the presence of uncertain kinematics and dynamics. Our control objective is to realise synchronisation without the measurements of task-space velocity. The communication topology is assumed to be directed graphs containing a spanning tree. A decentralised task-space observer with kinematic parameter updating is proposed to avoid the reliance of task-space velocity. Based on the observer, we propose the distributed adaptive synchronisation controller for two cases: (1) the leaderless consensus case and (2) the leader-follower case, where all the followers track the convex hull spanned by the virtual leaders and for each follower, it is required that there exists at least one leader that has a directed path to the follower. The asymptotic synchronisation is proved with Lyapunov analysis and input-output stability analysis tools. Simulations with multiple robotic agents are performed to show the effectiveness of the proposed schemes.

  17. A new contrast agent for radiological and dissection studies of the arterial network of anatomic specimens.

    PubMed

    Bulla, A; Casoli, C; Farace, F; Mazzarello, V; De Luca, L; Rubino, C; Montella, A

    2014-01-01

    The aim of the present study is to propose a new contrast agent that can be easily applied both to CT and dissection studies to replace lead oxide based formulas for comparative anatomical analyses of the vascularisation of cadaveric specimens. The infusion material was an epoxy resin, especially modified by the addition of barium sulphate to enhance its radiopacity. The final copolymer was toxicologically safe. To test the properties of the new material, several cadaveric limb injections were performed. The injected specimens were both CT scanned to perform 3D vascular reconstructions and dissected by anatomical planes. There was a perfect correspondence between the image studies and the dissections: even the smallest arteries on CT scan can be identified on the specimen and vice versa. The properties of the epoxy allowed an easy dissection of the vessels. The new imaging techniques available today, such as CT scan, can evaluate the vascular anatomy in high detail and 3D. This new contrast agent may help realising detailed vascular studies comparing CT scan results with anatomical dissections. Moreover, it may be useful for teaching surgical skills in the field of plastic surgery.

  18. Reinforcement of an electrically conductive network with ethanol as a dispersing agent in the slurry preparation step

    NASA Astrophysics Data System (ADS)

    Jung, Jiwon; Jang, Jihyun; Chae, O. B.; Yoon, Taeho; Ryu, Ji Heon; Oh, Seung M.

    2015-08-01

    Ethanol is added as a dispersing agent in the slurry preparation step for lithium-ion batteries, in which lithium titanium oxide (Li4Ti5O12, LTO) and conductive carbon (Super P) are dispersed into an aqueous solution of polymer binder (polyacrylic acid). The addition of ethanol suppresses the agglomeration of conductive carbon particles enabling homogeneous mixing of the electrode ingredients in the slurry, which eventually yields a uniform distribution of the LTO and Super P particles in the composite electrodes. Because of the reinforced electrically conductive network formed between the LTO and Super P, the electrode resistance becomes smaller, and thus, a high rate capability is achieved; the capacity of the LTO at 30 C is 73% of that observed at 0.5 C.

  19. On the Peter Principle: An agent based investigation into the consequential effects of social networks and behavioural factors

    NASA Astrophysics Data System (ADS)

    Fetta, A. G.; Harper, P. R.; Knight, V. A.; Vieira, I. T.; Williams, J. E.

    2012-05-01

    The Peter Principle is a theory that provides a paradoxical explanation for job incompetence in a hierarchical organisation. It argues that should staff be competent at a given level, their competence may not be implicit at higher levels due to the differences in the skill set required. Furthering the work of a recent investigation into the Peter Principle utilising agent based simulation, this paper explores external factors upon varying promotion strategies to assess efficiency. Through additional elements of social networks and organisational thought, a more representative view of workplace interaction is presented. Results of the simulation found that although the Peter Principle affects efficiency, it may not be to the levels previously suggested. Furthermore promotion on merit provided the most favourable maximum and minimum efficiency margins, given the absence of clear evidence pertaining to the existence of the Peter Principle.

  20. 10 CFR 603.1230 - Commercial firm.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 10 Energy 4 2011-01-01 2011-01-01 false Commercial firm. 603.1230 Section 603.1230 Energy... Used in this Part § 603.1230 Commercial firm. A for-profit firm or segment of a for-profit firm (e.g., a division or other business unit) that does a substantial portion of its business in the...

  1. 10 CFR 603.1230 - Commercial firm.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 4 2014-01-01 2014-01-01 false Commercial firm. 603.1230 Section 603.1230 Energy DEPARTMENT OF ENERGY (CONTINUED) ASSISTANCE REGULATIONS TECHNOLOGY INVESTMENT AGREEMENTS Definitions of Terms Used in this Part § 603.1230 Commercial firm. A for-profit firm or segment of a for-profit firm (e.g...

  2. 10 CFR 603.1230 - Commercial firm.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 4 2012-01-01 2012-01-01 false Commercial firm. 603.1230 Section 603.1230 Energy DEPARTMENT OF ENERGY (CONTINUED) ASSISTANCE REGULATIONS TECHNOLOGY INVESTMENT AGREEMENTS Definitions of Terms Used in this Part § 603.1230 Commercial firm. A for-profit firm or segment of a for-profit firm (e.g...

  3. 10 CFR 603.1230 - Commercial firm.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 4 2013-01-01 2013-01-01 false Commercial firm. 603.1230 Section 603.1230 Energy DEPARTMENT OF ENERGY (CONTINUED) ASSISTANCE REGULATIONS TECHNOLOGY INVESTMENT AGREEMENTS Definitions of Terms Used in this Part § 603.1230 Commercial firm. A for-profit firm or segment of a for-profit firm (e.g...

  4. 32 CFR 37.1250 - Commercial firm.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... REGULATIONS TECHNOLOGY INVESTMENT AGREEMENTS Definitions of Terms Used in This Part § 37.1250 Commercial firm. A for-profit firm or segment of a for-profit firm (e.g., a division or other business unit) that... 32 National Defense 1 2010-07-01 2010-07-01 false Commercial firm. 37.1250 Section 37.1250...

  5. Modulation of attention network activation under antidepressant agents in healthy subjects.

    PubMed

    Graf, Heiko; Abler, Birgit; Hartmann, Antonie; Metzger, Coraline D; Walter, Martin

    2013-07-01

    While antidepressants are supposed to exert similar effects on mood and drive via various mechanisms of action, diverging effects are observed regarding side-effects and accordingly on neural correlates of motivation, emotion, reward and salient stimuli processing as a function of the drugs impact on neurotransmission. In the context of erotic stimulation, a unidirectional modulation of attentional functioning despite opposite effects on sexual arousal has been suggested for the selective serotonin reuptake-inhibitor (SSRI) paroxetine and the selective dopamine and noradrenaline reuptake-inhibitor (SDNRI) bupropion. To further elucidate the effects of antidepressant-related alterations of neural attention networks, we investigated 18 healthy males under subchronic administration (7 d) of paroxetine (20 mg), bupropion (150 mg) and placebo within a randomized placebo-controlled cross-over double-blind functional magnetic resonance imaging (fMRI) design during an established preceding attention task. Neuropsychological effects beyond the fMRI-paradigm were assessed by measuring alertness and divided attention. Comparing preceding attention periods of salient vs. neutral pictures, we revealed congruent effects of both drugs vs. placebo within the anterior midcingulate cortex, dorsolateral prefrontal cortex, anterior prefrontal cortex, superior temporal gyrus, anterior insula and the thalamus. Relatively decreased activation in this network was paralleled by slower reaction times in the divided attention task in both verum conditions compared to placebo. Our results suggest similar effects of antidepressant treatments on behavioural and neural attentional functioning by diverging neurochemical pathways. Concurrent alterations of brain regions within a fronto-parietal and cingulo-opercular attention network for top-down control could point to basic neural mechanisms of antidepressant action irrespective of receptor profiles.

  6. Antiplatelet Agents for the Secondary Prevention of Ischemic Stroke or Transient Ischemic Attack: A Network Meta-Analysis.

    PubMed

    Wang, Wen; Zhang, Lu; Liu, Weiming; Zhu, Qin; Lan, Qing; Zhao, Jizong

    2016-05-01

    Stroke can cause high morbidity and mortality, and ischemic stroke (IS) and transient ischemic attack (TIA) patients have a high stroke recurrence rate. Antiplatelet agents are the standard therapy for these patients, but it is often difficult for clinicians to select the best therapy from among the multiple treatment options. We therefore performed a network meta-analysis to estimate the efficacy of antiplatelet agents for secondary prevention of recurrent stroke. We systematically searched 3 databases (PubMed, Embase, and Cochrane) for relevant studies published through August 2015. The primary end points of this meta-analysis were overall stroke, hemorrhagic stroke, and fatal stroke. A total of 30 trials were included in our network meta-analysis and abstracted data. Among the therapies evaluated in the included trials, the estimates for overall stroke and hemorrhagic stroke for cilostazol (Cilo) were significantly better than those for aspirin (odds ratio [OR] = .64, 95% credibility interval [CrI], .45-.91; OR = .23, 95% CrI, .08-.58). The estimate for fatal stroke was highest for Cilo plus aspirin combination therapy, followed by Cilo therapy. The results of our meta-analysis indicate that Cilo significantly improves overall stroke and hemorrhagic stroke in IS or TIA patients and reduces fatal stroke, but with low statistical significance. Our results also show that Cilo was significantly more efficient than other therapies in Asian patients; therefore, future trials should focus on Cilo treatment for secondary prevention of recurrent stroke in non-Asian patients. Copyright © 2016 National Stroke Association. Published by Elsevier Inc. All rights reserved.

  7. Specificity improvement for network distributed physiologic alarms based on a simple deterministic reactive intelligent agent in the critical care environment.

    PubMed

    Blum, James M; Kruger, Grant H; Sanders, Kathryn L; Gutierrez, Jorge; Rosenberg, Andrew L

    2009-02-01

    Automated physiologic alarms are available in most commercial physiologic monitors. However, due to the variability of data coming from the physiologic sensors describing the state of patients, false positive alarms frequently occur. Each alarm requires review and documentation, which consumes clinicians' time, may reduce patient safety through 'alert fatigue' and makes automated physician paging infeasible. To address these issues a computerized architecture based on simple reactive intelligent agent technology has been developed and implemented in a live critical care unit to facilitate the investigation of deterministic algorithms for the improvement of the sensitivity and specificity of physiologic alarms. The initial proposed algorithm uses a combination of median filters and production rules to make decisions about what alarms to generate. The alarms are used to classify the state of patients and alerts can be easily viewed and distributed using standard network, SQL database and Internet technologies. To evaluate the proposed algorithm, a 28 day study was conducted in the University of Michigan Medical Center's 14 bed Cardiothoracic Intensive Care Unit. Alarms generated by patient monitors, the intelligent agent and alerts documented on patient flow sheets were compared. Significant improvements in the specificity of the physiologic alarms based on systolic and mean blood pressure was found on average to be 99% and 88% respectively. Even through significant improvements were noted based on this algorithm much work still needs to be done to ensure the sensitivity of alarms and methods to handle spurious sensor data due to patient or sensor movement and other influences.

  8. Knowledge Management in Small Firms

    NASA Astrophysics Data System (ADS)

    Panyasorn, Jessada; Panteli, Niki; Powell, Philip

    This paper explores knowledge management in small and medium-sized firms (SMEs). It investigates the use of Lotus Notes in SMEs of a developing country as a counterpoint to the large firm, developed country emphasis of existing research. It develops taxonomy of Lotus Notes use within the context of different knowledge management processes; notably communicating, co-ordinating and collaborating. The study employs an interpretive approach using three case studies. The key findings suggest that publishing, searching, sharing and retrieving are the user modes for enabling sharing and storing information. Evidence of knowledge creation is found at the departmental level but not at the organizational level. Further, small firms may explore more groupware potential than large organizations and this reflects their different context. Finally, implications for further research are identified.

  9. Phase Transitions in Systems of Self-Propelled Agents and Related Network Models

    NASA Astrophysics Data System (ADS)

    Aldana, M.; Dossetti, V.; Huepe, C.; Kenkre, V. M.; Larralde, H.

    2007-03-01

    An important characteristic of flocks of birds, schools of fish, and many similar assemblies of self-propelled particles is the emergence of states of collective order in which the particles move in the same direction. When noise is added into the system, the onset of such collective order occurs through a dynamical phase transition controlled by the noise intensity. While originally thought to be continuous, the phase transition has been claimed to be discontinuous on the basis of recently reported numerical evidence. We address this issue by analyzing two representative network models closely related to systems of self-propelled particles. We present analytical as well as numerical results showing that the nature of the phase transition depends crucially on the way in which noise is introduced into the system.

  10. A Neural Network Approach to Intention Modeling for User-Adapted Conversational Agents.

    PubMed

    Griol, David; Callejas, Zoraida

    2016-01-01

    Spoken dialogue systems have been proposed to enable a more natural and intuitive interaction with the environment and human-computer interfaces. In this contribution, we present a framework based on neural networks that allows modeling of the user's intention during the dialogue and uses this prediction to dynamically adapt the dialogue model of the system taking into consideration the user's needs and preferences. We have evaluated our proposal to develop a user-adapted spoken dialogue system that facilitates tourist information and services and provide a detailed discussion of the positive influence of our proposal in the success of the interaction, the information and services provided, and the quality perceived by the users.

  11. A Neural Network Approach to Intention Modeling for User-Adapted Conversational Agents

    PubMed Central

    Griol, David

    2016-01-01

    Spoken dialogue systems have been proposed to enable a more natural and intuitive interaction with the environment and human-computer interfaces. In this contribution, we present a framework based on neural networks that allows modeling of the user's intention during the dialogue and uses this prediction to dynamically adapt the dialogue model of the system taking into consideration the user's needs and preferences. We have evaluated our proposal to develop a user-adapted spoken dialogue system that facilitates tourist information and services and provide a detailed discussion of the positive influence of our proposal in the success of the interaction, the information and services provided, and the quality perceived by the users. PMID:26819592

  12. Phase transitions in systems of self-propelled agents and related network models.

    PubMed

    Aldana, M; Dossetti, V; Huepe, C; Kenkre, V M; Larralde, H

    2007-03-02

    An important characteristic of flocks of birds, schools of fish, and many similar assemblies of self-propelled particles is the emergence of states of collective order in which the particles move in the same direction. When noise is added into the system, the onset of such collective order occurs through a dynamical phase transition controlled by the noise intensity. While originally thought to be continuous, the phase transition has been claimed to be discontinuous on the basis of recently reported numerical evidence. We address this issue by analyzing two representative network models closely related to systems of self-propelled particles. We present analytical as well as numerical results showing that the nature of the phase transition depends crucially on the way in which noise is introduced into the system.

  13. Combining Multi-Agent Systems and Wireless Sensor Networks for Monitoring Crop Irrigation.

    PubMed

    Villarrubia, Gabriel; Paz, Juan F De; Iglesia, Daniel H De La; Bajo, Javier

    2017-08-02

    Monitoring mechanisms that ensure efficient crop growth are essential on many farms, especially in certain areas of the planet where water is scarce. Most farmers must assume the high cost of the required equipment in order to be able to streamline natural resources on their farms. Considering that many farmers cannot afford to install this equipment, it is necessary to look for more effective solutions that would be cheaper to implement. The objective of this study is to build virtual organizations of agents that can communicate between each other while monitoring crops. A low cost sensor architecture allows farmers to monitor and optimize the growth of their crops by streamlining the amount of resources the crops need at every moment. Since the hardware has limited processing and communication capabilities, our approach uses the PANGEA architecture to overcome this limitation. Specifically, we will design a system that is capable of collecting heterogeneous information from its environment, using sensors for temperature, solar radiation, humidity, pH, moisture and wind. A major outcome of our approach is that our solution is able to merge heterogeneous data from sensors and produce a response adapted to the context. In order to validate the proposed system, we present a case study in which farmers are provided with a tool that allows us to monitor the condition of crops on a TV screen using a low cost device.

  14. Combining Multi-Agent Systems and Wireless Sensor Networks for Monitoring Crop Irrigation

    PubMed Central

    Villarrubia, Gabriel; De Paz, Juan F.; De La Iglesia, Daniel H.; Bajo, Javier

    2017-01-01

    Monitoring mechanisms that ensure efficient crop growth are essential on many farms, especially in certain areas of the planet where water is scarce. Most farmers must assume the high cost of the required equipment in order to be able to streamline natural resources on their farms. Considering that many farmers cannot afford to install this equipment, it is necessary to look for more effective solutions that would be cheaper to implement. The objective of this study is to build virtual organizations of agents that can communicate between each other while monitoring crops. A low cost sensor architecture allows farmers to monitor and optimize the growth of their crops by streamlining the amount of resources the crops need at every moment. Since the hardware has limited processing and communication capabilities, our approach uses the PANGEA architecture to overcome this limitation. Specifically, we will design a system that is capable of collecting heterogeneous information from its environment, using sensors for temperature, solar radiation, humidity, pH, moisture and wind. A major outcome of our approach is that our solution is able to merge heterogeneous data from sensors and produce a response adapted to the context. In order to validate the proposed system, we present a case study in which farmers are provided with a tool that allows us to monitor the condition of crops on a TV screen using a low cost device. PMID:28767089

  15. Comparative studies on some quality attributes of firm tofu sterilized with traditional and autoclaving methods.

    PubMed

    Huang, Tzou-Chi; Fu, Hui-Yin; Ho, Chi-Tang

    2003-01-01

    An innovative retort cooking method was developed for firm tofu sterilization to replace the traditional hydrogen peroxide treatment. The caramelized firm tofu was sterilized by autoclaving at 105 degrees C for 20 min, which led to a 3 log cycle reduction of total plate count. Shelf life of the processed firm tofu was extended at least 3 months. As compared with chemical treatment, thermal treatment degraded total and individual isoflavones to a lesser extent, and only minor changes were observed. The percent DPPH free radical scavenging capacity of autoclaved firm tofu was significantly higher than that of the hydrogen peroxide treated samples. Even after prolonged heat treatment, the three-dimensional network structure of the autoclaved firm tofu did not change significantly. Texture profile analysis and sensory evaluation confirmed autoclaved firm tofu to be acceptable.

  16. Adaptive Control Parameters for Dispersal of Multi-Agent Mobile Ad Hoc Network (MANET) Swarms

    SciTech Connect

    Kurt Derr; Milos Manic

    2013-11-01

    A mobile ad hoc network is a collection of independent nodes that communicate wirelessly with one another. This paper investigates nodes that are swarm robots with communications and sensing capabilities. Each robot in the swarm may operate in a distributed and decentralized manner to achieve some goal. This paper presents a novel approach to dynamically adapting control parameters to achieve mesh configuration stability. The presented approach to robot interaction is based on spring force laws (attraction and repulsion laws) to create near-optimal mesh like configurations. In prior work, we presented the extended virtual spring mesh (EVSM) algorithm for the dispersion of robot swarms. This paper extends the EVSM framework by providing the first known study on the effects of adaptive versus static control parameters on robot swarm stability. The EVSM algorithm provides the following novelties: 1) improved performance with adaptive control parameters and 2) accelerated convergence with high formation effectiveness. Simulation results show that 120 robots reach convergence using adaptive control parameters more than twice as fast as with static control parameters in a multiple obstacle environment.

  17. Recycling and reuse of waste from electricity distribution networks as reinforcement agents in polymeric composites.

    PubMed

    Zimmermann, Matheus V G; Zattera, Ademir J

    2013-07-01

    Of the waste generated from electricity distribution networks, wooden posts treated with chromated copper arsenate (CCA) and ceramic insulators make up the majority of the materials for which no effective recycling scheme has been developed. This study aims to recycle and reuse this waste as reinforcement elements in polymer composites and hybrid composites, promoting an ecologically and economically viable alternative for the disposal of this waste. The CCA wooden posts were cut, crushed and recycled via acid leaching using 0.2 and 0.4N H2SO4 in triplicate at 70°C and then washed and dried. The ceramic insulators were fragmented in a hydraulic press and separated by particle size using a vibrating sieve. The composites were mixed in a twin-screw extruder and injected into the test specimens, which were subjected to physical, mechanical, thermal and morphological characterization. The results indicate that the acid treatment most effective for removing heavy metals in the wood utilizes 0.4NH2SO4. However, the composites made from wood treated with 0.2NH2SO4 exhibited the highest mechanical properties of the composites, whereas the use of a ceramic insulator produces composites with better thermal stability and impact strength. This study is part of the research and development project of ANEEL (Agência Nacional de Energia Elétrica) and funded by CPFL (Companhia Paulista de Força e Luz). Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. Essays in economics: 1. Pre-committed government spending and partisan politics. 2. Investment in energy efficiency: Do the characteristics of firms matter? 3. Information processing and organizational structure

    NASA Astrophysics Data System (ADS)

    Watkins, William Edward, Jr.

    1. Spending commitments requiring future outlays are important for understanding partisan politics because they prevent a conservative government from scaling back spending programs. In a one-government-good model, a "stubborn liberal" policy maker can use precommitted spending to prevent a later conservative government from imposing spending cuts. In a model where parties differ about spending priorities, re-election uncertainty creates a bias towards higher government spending and higher taxes. 2. The literature on energy efficiency provides examples of profitable technologies that are not universally adopted. Theory indicates that firms should undertake all investments with a positive net present value, and that the discount rate for computing the present value of a project should be the return available on other projects in the same risk class, not on characteristics of the firm. This model is tested by examining whether firms' characteristics influence their decision to join the Environmental Protection Agency's Green Lights program. A discrete choice regression is estimated over a sample of participating and non-participating firms. Missing values in the data matrix are replaced with multiple imputations using the EM algorithm. The results show that: (1) substantial improvements in the power of hypothesis tests can be achieved through imputation of missing data, and (2) characteristics of firms do affect their decision to join Green Lights. 3. Standard theories of the firm stress profit maximization as the foundation for derivation of predictable behavior. Yet evidence continues to accumulate that firms do not act as required by the neoclassical framework. Instead of being represented by ever more elaborate maximization models, the firm can be modeled simply as a network of information-processing agents. The actions of the firm are then a function only of the network structure and the information-processing capabilities of the agents. This approach can be

  19. Changing the Firm through Training.

    ERIC Educational Resources Information Center

    Verdier, Eric

    1992-01-01

    A survey of French research by CEREQ ("A French research centre for analysis of occupations and of vocational education and training") shows that firms have undertaken a number of experiments, most of them large scale, to retrain their work force. These initiatives are situated within a general context of change. Training programs based…

  20. Path scanning for the detection of anomalous subgraphs and use of DNS requests and host agents for anomaly/change detection and network situational awareness

    DOEpatents

    Neil, Joshua Charles; Fisk, Michael Edward; Brugh, Alexander William; Hash, Jr., Curtis Lee; Storlie, Curtis Byron; Uphoff, Benjamin; Kent, Alexander

    2017-01-31

    A system, apparatus, computer-readable medium, and computer-implemented method are provided for detecting anomalous behavior in a network. Historical parameters of the network are determined in order to determine normal activity levels. A plurality of paths in the network are enumerated as part of a graph representing the network, where each computing system in the network may be a node in the graph and the sequence of connections between two computing systems may be a directed edge in the graph. A statistical model is applied to the plurality of paths in the graph on a sliding window basis to detect anomalous behavior. Data collected by a Unified Host Collection Agent ("UHCA") may also be used to detect anomalous behavior.

  1. Persistent Patterns in Trading Firms' Actions

    NASA Astrophysics Data System (ADS)

    Zamani, Neda; Doyne Farmer, J.

    2007-03-01

    To understand the dynamics of price formation in financial markets, we take the approach of investigating the actions of market participants. We examine the impact of the participating firms on the price and find that different firms have different patterns of impact. Each firm can be representative of many traders with different trading habits and strategies but nevertheless we observe statistically significant differences in the firms' market impacts. We also investigate a method of clustering the firms based on a simplified conception of strategies. We find consistent clusters and patterns in firm strategies and show that these relations are statistically significant.

  2. Comparison of Pathogen Eradication Rate and Safety of Anti-Bacterial Agents for Bronchitis: A Network Meta-Analysis.

    PubMed

    Wang, Jinghua; Xu, Haiyang; Wang, Dunwei; Li, Mingxian

    2017-10-01

    A large number of population in both developing and developed countries are affected by bronchitis, among all the factors, bacterial infection was considered as a critical cause of acute exacerbations of chronic bronchitis. Although several anti-bacterial agents were proved to have the effect of alleviating bronchitis, their relative efficacies and potential side effects remained not clear. We are keen to compare the pathogen eradication rate and safety of anti-bacterial agents for bronchitis. Relevant studies were searched in multiple sources and data were extracted from eligible studies. Then conventional meta-analysis and network meta-analysis (NMA) were conducted to determine the relative efficacy and safety of bronchitis medications. The efficacy of bronchitis medications was determined by using the outcome of pathogen eradication, including total pathogen eradication, pathogen eradication of Haemophilus influenzae, pathogen eradication of Moraxella catarrhalis, and pathogen eradication of Streptococcus pneumoniae. In addition, safety was assessed by using the outcome of adverse effects and diarrhoea. A 27 RCTs with 9,414 participants were included in the study. Among the medications, gatifloxacin and moxifloxacin exhibited better performance than clarithromycin with respect to pathogen eradication of H. influenzae (OR = 21.37, CI: 1.22-541.28; OR = 7.43, CI: 1.79-30.50). Clarithromycin, gemifloxacin, levofloxacin, moxifloxacin, and telithromycin appeared to be more preferable than amoxicillin + clavulanate and azithromycin with respect to diarrhoea (all OR <1). The surface under the cumulative ranking curve (SUCRA) results suggested that gemifloxacin and levofloxacin had a relatively high ranking in total pathogen eradication, whereas amoxicillin + clavulanate and azithromycin exhibited relatively lower ranking with respect to adverse effects and diarrhoea. Gemifloxacin and levofloxacin are more preferable than others for lowering respiratory

  3. Comparative Efficacy and Safety of Antihypertensive Agents for Adult Diabetic Patients with Microalbuminuric Kidney Disease: A Network Meta-Analysis.

    PubMed

    Huang, Rongzhong; Feng, Yuxing; Wang, Ying; Qin, Xiaoxia; Melgiri, Narayan Dhruvaraj; Sun, Yang; Li, Xingsheng

    2017-01-01

    Antihypertensive treatment mitigates the progression of chronic kidney disease. Here, we comparatively assessed the effects of antihypertensive agents in normotensive and hypertensive diabetic patients with microalbuminuric kidney disease. MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials were systematically searched for randomized controlled trials (RCTs) comparing oral antihypertensive agents in adult diabetic patients with microalbuminuria. The primary efficacy outcome was reduction in albuminuria, and the primary safety outcomes were dry cough, presyncope, and edema. Random-effects pairwise and Bayesian network meta-analyses were performed to produce outcome estimates for all RCTs, only hypertensive RCTs, or only normotensive RCTs. Surface under the cumulative ranking (SUCRA) probability rankings were calculated for all outcomes. Sensitivity analyses on type 2 diabetes status, age, or follow-up duration were also performed. A total of 38 RCTs were included in the meta-analyses. The angiotensin-converting enzyme inhibitor-calcium channel blocker (ACEI-CCB) combination therapy of captopril+diltiazem was most efficacious in reducing albuminuria irrespective of blood pressure status. However, the ACEI-angiotensin receptor blocker (ACEI-ARB) combination therapy of trandolapril+candesartan was the most efficacious in reducing albuminuria for normotensive patients, while the ACEI-CCB combination therapy of fosinopril+amlodipine was the most efficacious in reducing albuminuria for hypertensive patients. The foregoing combination therapies displayed inferior safety profiles relative to ACEI monotherapy with respect to dry cough, presyncope, and edema. With respect to type 2 diabetic patients with microalbuminuria, the Chinese herbal medicine Tangshen formula followed by the ACEI ramipril were the most efficacious in reducing albuminuria. Trandolapril+candesartan appears to be the most efficacious intervention for reducing albuminuria for

  4. Comparative Efficacy and Safety of Antihypertensive Agents for Adult Diabetic Patients with Microalbuminuric Kidney Disease: A Network Meta-Analysis

    PubMed Central

    Huang, Rongzhong; Feng, Yuxing; Wang, Ying; Qin, Xiaoxia; Melgiri, Narayan Dhruvaraj; Sun, Yang; Li, Xingsheng

    2017-01-01

    Background Antihypertensive treatment mitigates the progression of chronic kidney disease. Here, we comparatively assessed the effects of antihypertensive agents in normotensive and hypertensive diabetic patients with microalbuminuric kidney disease. Methods MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials were systematically searched for randomized controlled trials (RCTs) comparing oral antihypertensive agents in adult diabetic patients with microalbuminuria. The primary efficacy outcome was reduction in albuminuria, and the primary safety outcomes were dry cough, presyncope, and edema. Random-effects pairwise and Bayesian network meta-analyses were performed to produce outcome estimates for all RCTs, only hypertensive RCTs, or only normotensive RCTs. Surface under the cumulative ranking (SUCRA) probability rankings were calculated for all outcomes. Sensitivity analyses on type 2 diabetes status, age, or follow-up duration were also performed. Results A total of 38 RCTs were included in the meta-analyses. The angiotensin-converting enzyme inhibitor-calcium channel blocker (ACEI-CCB) combination therapy of captopril+diltiazem was most efficacious in reducing albuminuria irrespective of blood pressure status. However, the ACEI-angiotensin receptor blocker (ACEI-ARB) combination therapy of trandolapril+candesartan was the most efficacious in reducing albuminuria for normotensive patients, while the ACEI-CCB combination therapy of fosinopril+amlodipine was the most efficacious in reducing albuminuria for hypertensive patients. The foregoing combination therapies displayed inferior safety profiles relative to ACEI monotherapy with respect to dry cough, presyncope, and edema. With respect to type 2 diabetic patients with microalbuminuria, the Chinese herbal medicine Tangshen formula followed by the ACEI ramipril were the most efficacious in reducing albuminuria. Conclusions Trandolapril+candesartan appears to be the most efficacious intervention

  5. Phosphate-Binding Agents in Adults With CKD: A Network Meta-analysis of Randomized Trials.

    PubMed

    Palmer, Suetonia C; Gardner, Sharon; Tonelli, Marcello; Mavridis, Dimitris; Johnson, David W; Craig, Jonathan C; French, Richard; Ruospo, Marinella; Strippoli, Giovanni F M

    2016-11-01

    Guidelines preferentially recommend noncalcium phosphate binders in adults with chronic kidney disease (CKD). We compare and rank phosphate-binder strategies for CKD. Network meta-analysis. Adults with CKD. Randomized trials with allocation to phosphate binders. Sevelamer, lanthanum, iron, calcium, colestilan, bixalomer, nicotinic acid, and magnesium. The primary outcome was all-cause mortality. Additional outcomes were cardiovascular mortality, myocardial infarction, stroke, adverse events, serum phosphorus and calcium levels, and coronary artery calcification. 77 trials (12,562 participants) were included. Most (62 trials in 11,009 patients) studies were performed in a dialysis population. Trials were generally of short duration (median, 6 months) and had high risks of bias. All-cause mortality was ascertained in 20 studies during 86,744 patient-months of follow-up. There was no evidence that any drug class lowered mortality or cardiovascular events when compared to placebo. Compared to calcium, sevelamer reduced all-cause mortality (OR, 0.39; 95% CI, 0.21-0.74), whereas treatment effects of lanthanum, iron, and colestilan were not significant (ORs of 0.78 [95% CI, 0.16-3.72], 0.37 [95% CI, 0.09-1.60], and 0.55 [95% CI, 0.07-4.43], respectively). Lanthanum caused nausea, whereas sevelamer posed the highest risk for constipation and iron caused diarrhea. All phosphate binders lowered serum phosphorus levels to a greater extent than placebo, with iron ranked as the best treatment. Sevelamer and lanthanum posed substantially lower risks for hypercalcemia than calcium. Limited testing of consistency; short follow-up. There is currently no evidence that phosphate-binder treatment reduces mortality compared to placebo in adults with CKD. It is not clear whether the higher mortality with calcium versus sevelamer reflects whether there is net harm associated with calcium, net benefit with sevelamer, both, or neither. Iron-based binders show evidence of greater phosphate

  6. An Agent-Based Modeling Approach to Integrate Tsunami Science, Human Behavior, and Unplanned Network Disruptions for Nearfield Tsunami Evacuation

    NASA Astrophysics Data System (ADS)

    Cox, D. T.; Wang, H.; Cramer, L.; Mostafizi, A.; Park, H.

    2016-12-01

    For the Cascadia Subduction Zone (CSZ) and other extreme near-field tsunami hazards, coastal residents and tourist must evacuate within 15 to 30 minutes immediately following intense ground-shaking and will be confronted with an array of choices: Should I evacuate on foot or by car? Alone, or find friends and family first? Head for high ground far away, or seek shelter a nearby building? How will the roads and bridges be affected by the preceding earthquake? In this project, we integrate the disciplines of tsunami inundation science, sociology, and civil engineering to investigate how decision-making by individual evacuees with respect to milling time, mode choice, and destination affects their life safety. We use an Agent-Based Model (ABM) to create credible scenarios for near-field tsunami evacuation. The ABM integrates (1) the time-dependent tsunami inundation computed separately using NOAA's ComMIT/MOST model, (2) population layers to account for variations in population density of residents and tourist, (3) evacuation route network including roads, bridges and foot paths for multi-modal transportation, and (4) evacuation destinations for horizontal and vertical evacuation. For this project, we apply the ABM at two locations: the city Seaside, OR, and South Beach State Park in Newport, OR. In the Seaside scenario, we show how unplanned network disruption - e.g. the partial or total failure of bridges due to the preceding earthquake - will affect life safety and show how the ABM can be used to provide retrofit strategies. For South Beach, we show how alternative routing can have a substantial impact on life safety. The ABM shows results that are initially counterintuitive. For the Seaside example, resource allocation for bridge retrofit favors investments in nodes and links not necessarily in close proximity to population centers. For the South Beach example, the routes which provide for the lowest risk (maximum life safety) are not always those with the

  7. Tailoring the network properties of Ca2+ crosslinked Aloe vera polysaccharide hydrogels for in situ release of therapeutic agents.

    PubMed

    McConaughy, Shawn D; Kirkland, Stacey E; Treat, Nicolas J; Stroud, Paul A; McCormick, Charles L

    2008-11-01

    Properties of Aloe vera galacturonate hydrogels formed via Ca(2+) crosslinking have been studied in regard to key parameters influencing gel formation including molecular weight, ionic strength, and molar ratio of Ca(2+) to COO(-) functionality. Dynamic oscillatory rheology and pulsed field gradient NMR (PFG-NMR) studies have been conducted on hydrogels formed at specified Ca(2+) concentrations in the presence and absence of Na(+) and K(+) ions in order to assess the feasibility of in situ gelation for controlled delivery of therapeutics. Aqueous Ca(2+) concentrations similar to those present in nasal and subcutaneous fluids induce the formation of elastic Aloe vera polysaccharide (AvP) hydrogel networks. By altering the ratio of Ca(2+) to COO (-) functionality, networks may be tailored to provide elastic modulus (G') values between 20 and 20000 Pa. The Aloe vera polysaccharide exhibits time-dependent phase separation in the presence of monovalent electrolytes. Thus the relative rates of calcium induced gelation and phase separation become major considerations when designing a system for in situ delivery applications where both monovalent (Na(+), K(+)) and divalent (Ca(2+)) ions are present. PFG-NMR and fluorescence microscopy confirm that distinctly different morphologies are present in gels formed in the presence and absence of 0.15 M NaCl. Curve fitting of theoretical models to experimental release profiles of fluorescein labeled dextrans indicate diffusion rates are related to hydrogel morphology. These studies suggest that for efficient in situ release of therapeutic agents, polymer concentrations should be maintained above the critical entanglement concentration ( Ce, 0.60 wt %) when [Ca(2+)]/[COO(-)] ratios are less than 1. Additionally, the monovalent electrolyte concentration in AvP solutions should not exceed 0.10 M prior to Ca(2+) crosslinking.

  8. 7 CFR 51.2843 - Fairly firm.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... FRESH FRUITS, VEGETABLES AND OTHER PRODUCTS 1,2 (INSPECTION, CERTIFICATION, AND STANDARDS) United States... Fairly firm. Fairly firm means that the onion may yield slightly to moderate pressure but is not...

  9. 7 CFR 51.2843 - Fairly firm.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... FRESH FRUITS, VEGETABLES AND OTHER PRODUCTS 1,2 (INSPECTION, CERTIFICATION, AND STANDARDS) United States... Fairly firm. Fairly firm means that the onion may yield slightly to moderate pressure but is not...

  10. 7 CFR 51.1156 - Firm.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Standards for Grades of Florida Oranges and Tangelos Definitions § 51.1156 Firm. Firm as applied to common oranges and tangelos means that the fruit is not soft, or noticeably wilted or flabby; as applied...

  11. 7 CFR 51.1167 - Fairly firm.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Standards for Grades of Florida Oranges and Tangelos Definitions § 51.1167 Fairly firm. Fairly firm as applied to common oranges and tangelos, means that the fruit may be slightly soft, but not bruised;...

  12. 7 CFR 51.1167 - Fairly firm.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Standards for Grades of Florida Oranges and Tangelos Definitions § 51.1167 Fairly firm. Fairly firm as applied to common oranges and tangelos, means that the fruit may be slightly soft, but not bruised;...

  13. 7 CFR 51.1156 - Firm.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Standards for Grades of Florida Oranges and Tangelos Definitions § 51.1156 Firm. Firm as applied to common oranges and tangelos means that the fruit is not soft, or noticeably wilted or flabby; as applied...

  14. A network-patch methodology for adapting agent-based models for directly transmitted disease to mosquito-borne disease.

    PubMed

    Manore, Carrie A; Hickmann, Kyle S; Hyman, James M; Foppa, Ivo M; Davis, Justin K; Wesson, Dawn M; Mores, Christopher N

    2015-01-01

    Mosquito-borne diseases cause significant public health burden and are widely re-emerging or emerging. Understanding, predicting, and mitigating the spread of mosquito-borne disease in diverse populations and geographies are ongoing modelling challenges. We propose a hybrid network-patch model for the spread of mosquito-borne pathogens that accounts for individual movement through mosquito habitats, extending the capabilities of existing agent-based models (ABMs) to include vector-borne diseases. The ABM are coupled with differential equations representing 'clouds' of mosquitoes in patches accounting for mosquito ecology. We adapted an ABM for humans using this method and investigated the importance of heterogeneity in pathogen spread, motivating the utility of models of individual behaviour. We observed that the final epidemic size is greater in patch models with a high risk patch frequently visited than in a homogeneous model. Our hybrid model quantifies the importance of the heterogeneity in the spread of mosquito-borne pathogens, guiding mitigation strategies.

  15. Optimal Routing and Control of Multiple Agents Moving in a Transportation Network and Subject to an Arrival Schedule and Separation Constraints

    NASA Technical Reports Server (NTRS)

    Sadovsky, A. V.; Davis, D.; Isaacson, D. R.

    2012-01-01

    We address the problem of navigating a set of moving agents, e.g. automated guided vehicles, through a transportation network so as to bring each agent to its destination at a specified time. Each pair of agents is required to be separated by a minimal distance, generally agent-dependent, at all times. The speed range, initial position, required destination, and required time of arrival at destination for each agent are assumed provided. The movement of each agent is governed by a controlled differential equation (state equation). The problem consists in choosing for each agent a path and a control strategy so as to meet the constraints and reach the destination at the required time. This problem arises in various fields of transportation, including Air Traffic Management and train coordination, and in robotics. The main contribution of the paper is a model that allows to recast this problem as a decoupled collection of problems in classical optimal control and is easily generalized to the case when inertia cannot be neglected. Some qualitative insight into solution behavior is obtained using the Pontryagin Maximum Principle. Sample numerical solutions are computed using a numerical optimal control solver.

  16. 10 CFR 603.1230 - Commercial firm.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Used in this Part § 603.1230 Commercial firm. A for-profit firm or segment of a for-profit firm (e.g., a division or other business unit) that does a substantial portion of its business in the commercial... 10 Energy 4 2010-01-01 2010-01-01 false Commercial firm. 603.1230 Section 603.1230 Energy...

  17. Using social network analysis and agent-based modelling to explore information flow using common operational pictures for maritime search and rescue operations.

    PubMed

    Baber, C; Stanton, N A; Atkinson, J; McMaster, R; Houghton, R J

    2013-01-01

    The concept of common operational pictures (COPs) is explored through the application of social network analysis (SNA) and agent-based modelling to a generic search and rescue (SAR) scenario. Comparing the command structure that might arise from standard operating procedures with the sort of structure that might arise from examining information-in-common, using SNA, shows how one structure could be more amenable to 'command' with the other being more amenable to 'control' - which is potentially more suited to complex multi-agency operations. An agent-based model is developed to examine the impact of information sharing with different forms of COPs. It is shown that networks using common relevant operational pictures (which provide subsets of relevant information to groups of agents based on shared function) could result in better sharing of information and a more resilient structure than networks that use a COP. SNA and agent-based modelling are used to compare different forms of COPs for maritime SAR operations. Different forms of COP change the communications structures in the socio-technical systems in which they operate, which has implications for future design and development of a COP.

  18. 40 CFR 745.89 - Firm certification.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... reimburse the firm for the excess amount. (2) After EPA receives a firm's application, EPA will take one of... of the firm, its principals, or its key employees does not show an unwillingness or inability to... perform renovations covered by this section in any State or Indian Tribal area that does not have a...

  19. Finding the "Right Staff" in Small Firms

    ERIC Educational Resources Information Center

    Barrett, Rowena; Neeson, Robyn; Billington, Leo

    2007-01-01

    Purpose: The purpose of this paper is to explore what owners of small firms are looking for from new employees. The aim is to pursue this in light of the debate around formality and informality of small firm HRM, exploring the extent to which the small firms studied had formalized HRM practices. Design/methodology/approach: The data reported here…

  20. Finding the "Right Staff" in Small Firms

    ERIC Educational Resources Information Center

    Barrett, Rowena; Neeson, Robyn; Billington, Leo

    2007-01-01

    Purpose: The purpose of this paper is to explore what owners of small firms are looking for from new employees. The aim is to pursue this in light of the debate around formality and informality of small firm HRM, exploring the extent to which the small firms studied had formalized HRM practices. Design/methodology/approach: The data reported here…

  1. Cooperative Education Programs in CPA Firms.

    ERIC Educational Resources Information Center

    Thibadoux, Gregory M.; Greenberg, Ira S.

    1986-01-01

    A study was conducted to determine the background of employed students in a sampling of accounting cooperative education programs, the nature of the final selection process made by the firms, the value of the students to the firm, and the value of the program to the students as perceived by members of the firm. (CT)

  2. Preparer une firme-reseau dans le transport routier des hydrocarbures le cas de TOTAL Madagascar

    NASA Astrophysics Data System (ADS)

    Razakamanifidiny, Patrick Dany

    2009-12-01

    In a dynamic context, a network firm is more and more suggested in scientific writings as a prevalent strategy to develop several firms in subcontracting link in order to satisfy the needs of their customers asking for products which are complex to manufacture. However, due to lack of sufficient preparation, most of network organizations fail. That's why it seems legitimate to explore an avenue of research on the preparation step of a network firm. How a third intermediary can develop and try out a change process in order to stimulate the commitment of films to organize themselves in network? This study is developed inside the framework of an intervention-research applied to the case of the oil distribution company TOTAL Madagascar. 71 weeks of intervention actions carried out with 27 subcontracting firms of hydrocarbon road transport located to Antananarivo are recorded within this framework. One of the critical elements in the oil distribution in Madagascar is the scarcity of the subcontracting firms of hydrocarbon road transport which are able to meet the required quality criterions. A lack of management standards observed in several small and medium enterprises of hydrocarbon road transport, a growth of the number of tankers accidents, and an insufficiency of individual resources to develop competences constitute the main reasons which explain this scarcity. By this way, a preparation step of a network firm was developed in order to increase the management competences of the subcontracting firms of hydrocarbon road transport, and to develop their capacity of collective learning. This step comes from the evolutionary perspective which consists in elaborating and implementing uprooting, movement and rooting activities related to a change implementation model taking reactions of the participating enterprises into consideration, through a change understanding process from objection to exploration until engagement. The realization of theses activities had been

  3. Essays on Firm Behavior in Developing Economies

    NASA Astrophysics Data System (ADS)

    Abeberese, Ama Baafra

    The performance of firms is central to growth in developing economies. A burgeoning literature within development economics seeks to understand the behavior of firms in developing countries and the constraints to their performance. This dissertation explores two types of constraints---infrastructure-related constraints and trade-related constraints---faced by manufacturing firms in developing countries. Despite the widely acknowledged importance of infrastructure for economic growth, there has been relatively little research on how infrastructure affects the decisions of firms. Electricity, in particular, is commonly cited by firms in developing countries as a major obstacle to their performance. In the first two chapters, I analyze the responses of firms to two types of electricity constraints, namely electricity prices and electricity shortages. Chapter 1 provides evidence on how electricity prices affect a firm's industry choice and productivity growth using data on Indian manufacturing firms. I construct an instrument for electricity price as the interaction between the price of coal paid by power utilities, which is arguably exogenous to firm characteristics, and the initial share of thermal generation in a state's total electricity generation capacity. I find that, in response to an exogenous increase in electricity price, firms reduce their electricity consumption and switch to industries with less electricity-intensive production processes. I also find that firm output, machine intensity and labor productivity decline with an increase in electricity price. In addition to these level effects, I show that firm output and productivity growth rates are negatively affected by high electricity prices. These results suggest that electricity constraints faced by firms may limit a country's growth by leading firms to operate in industries with fewer productivity-enhancing opportunities. Chapter 2 examines the impact of electricity shortages on firm investment. I

  4. Agent-Based Model Approach to Complex Phenomena in Real Economy

    NASA Astrophysics Data System (ADS)

    Iyetomi, H.; Aoyama, H.; Fujiwara, Y.; Ikeda, Y.; Souma, W.

    An agent-based model for firms' dynamics is developed. The model consists of firm agents with identical characteristic parameters and a bank agent. Dynamics of those agents are described by their balance sheets. Each firm tries to maximize its expected profit with possible risks in market. Infinite growth of a firm directed by the ``profit maximization" principle is suppressed by a concept of ``going concern". Possibility of bankruptcy of firms is also introduced by incorporating a retardation effect of information on firms' decision. The firms, mutually interacting through the monopolistic bank, become heterogeneous in the course of temporal evolution. Statistical properties of firms' dynamics obtained by simulations based on the model are discussed in light of observations in the real economy.

  5. Preparing culture change agents for academic medicine in a multi-institutional consortium: the C - change learning action network.

    PubMed

    Pololi, Linda H; Krupat, Edward; Schnell, Eugene R; Kern, David E

    2013-01-01

    Research suggests an ongoing need for change in the culture of academic medicine. This article describes the structure, activities and evaluation of a culture change project: the C - Change Learning Action Network (LAN) and its impact on participants. The LAN was developed to create the experience of a culture that would prepare participants to facilitate a culture in academic medicine that would be more collaborative, inclusive, relational, and that supports the humanity and vitality of faculty. Purposefully diverse faculty, leaders, and deans from 5 US medical schools convened in 2 1/2-day meetings biannually over 4 years. LAN meetings employed experiential, cognitive, and affective learning modes; innovative dialogue strategies; and reflective practice aimed at facilitating deep dialogue, relationship formation, collaboration, authenticity, and transformative learning to help members experience the desired culture. Robust aggregated qualitative and quantitative data collected from the 5 schools were used to inform and stimulate culture-change plans. Quantitative and qualitative evaluation methods were used. Participants indicated that a safe, supportive, inclusive, collaborative culture was established in LAN and highly valued. LAN members reported a deepened understanding of organizational change, new and valued interpersonal connections, increased motivation and resilience, new skills and approaches, increased self-awareness and personal growth, emotional connection to the issues of diversity and inclusion, and application of new learnings in their work. A carefully designed multi-institutional learning community can transform the way participants experience and view institutional culture. It can motivate and prepare them to be change agents in their own institutions. Copyright © 2013 The Alliance for Continuing Education in the Health Professions, the Society for Academic Continuing Medical Education, and the Council on CME, Association for Hospital Medical

  6. General practitioners' use of caries-preventive agents in adult patients versus pediatric patients: findings from the dental practice-based research network.

    PubMed

    Riley, Joseph L; Gordan, Valeria V; Rindal, D Brad; Fellows, Jeffrey L; Williams, O Dale; Ritchie, Lloyd K; Gilbert, Gregg H

    2010-06-01

    In this study, the authors tested the frequency of dentists' recommendations for and use of caries-preventive agents for children as compared with adults. The authors surveyed 467 general dentists in the Dental Practice-Based Research Network who practice within the United States and treat both pediatric and adult patients. They asked dentists to identify the percentage of their patients for whom they had administered or recommended dental sealants, in-office and at-home fluoride, chlorhexidine rinse and xylitol gum. Dentists were less likely to provide adult patients than pediatric patients with in-office caries-preventive agents. However, the rate at which they recommended at-home preventive regimens for the two groups of patients was similar. Dentists with a conservative approach to caries treatment were the most likely to use and recommend the use of caries-preventive agents at similar rates in adults as in children. In addition, dentists in practices with a greater number of patients who had dental insurance were significantly more likely to provide in-office fluoride or sealants to adult patients than to pediatric patients. General dentists use in-office caries-preventive agents more commonly with their pediatric patients than with their adult patients. General dentists should consider providing additional in-office caries-preventive agents for their adult patients who are at increased risk of experiencing dental caries.

  7. Small firm subsistence and market dimensionality

    NASA Astrophysics Data System (ADS)

    Bruggeman, Jeroen; Péli, Gábor

    2014-04-01

    In many markets, large and small firms coexist. As large firms can in principle out-compete small ones, the actual presence of the latter asks for an explanation. In ours, we focus on the dimensionality of markets, which can change as a consequence of product innovations, preference elaboration or institutions. We show that increasing market dimensionality substantially enlarges the market periphery relative to the market center, which creates new potential niches for small firms. We thereby provide a parsimonious explanation for small firm subsistence.

  8. An Agent-Based Model of Private Woodland Owner Management Behavior Using Social Interactions, Information Flow, and Peer-To-Peer Networks

    PubMed Central

    Huff, Emily Silver; Leahy, Jessica E.; Hiebeler, David; Weiskittel, Aaron R.; Noblet, Caroline L.

    2015-01-01

    Privately owned woodlands are an important source of timber and ecosystem services in North America and worldwide. Impacts of management on these ecosystems and timber supply from these woodlands are difficult to estimate because complex behavioral theory informs the owner’s management decisions. The decision-making environment consists of exogenous market factors, internal cognitive processes, and social interactions with fellow landowners, foresters, and other rural community members. This study seeks to understand how social interactions, information flow, and peer-to-peer networks influence timber harvesting behavior using an agent-based model. This theoretical model includes forested polygons in various states of ‘harvest readiness’ and three types of agents: forest landowners, foresters, and peer leaders (individuals trained in conservation who use peer-to-peer networking). Agent rules, interactions, and characteristics were parameterized with values from existing literature and an empirical survey of forest landowner attitudes, intentions, and demographics. The model demonstrates that as trust in foresters and peer leaders increases, the percentage of the forest that is harvested sustainably increases. Furthermore, peer leaders can serve to increase landowner trust in foresters. Model output and equations will inform forest policy and extension/outreach efforts. The model also serves as an important testing ground for new theories of landowner decision making and behavior. PMID:26562429

  9. An Agent-Based Model of Private Woodland Owner Management Behavior Using Social Interactions, Information Flow, and Peer-To-Peer Networks.

    PubMed

    Huff, Emily Silver; Leahy, Jessica E; Hiebeler, David; Weiskittel, Aaron R; Noblet, Caroline L

    2015-01-01

    Privately owned woodlands are an important source of timber and ecosystem services in North America and worldwide. Impacts of management on these ecosystems and timber supply from these woodlands are difficult to estimate because complex behavioral theory informs the owner's management decisions. The decision-making environment consists of exogenous market factors, internal cognitive processes, and social interactions with fellow landowners, foresters, and other rural community members. This study seeks to understand how social interactions, information flow, and peer-to-peer networks influence timber harvesting behavior using an agent-based model. This theoretical model includes forested polygons in various states of 'harvest readiness' and three types of agents: forest landowners, foresters, and peer leaders (individuals trained in conservation who use peer-to-peer networking). Agent rules, interactions, and characteristics were parameterized with values from existing literature and an empirical survey of forest landowner attitudes, intentions, and demographics. The model demonstrates that as trust in foresters and peer leaders increases, the percentage of the forest that is harvested sustainably increases. Furthermore, peer leaders can serve to increase landowner trust in foresters. Model output and equations will inform forest policy and extension/outreach efforts. The model also serves as an important testing ground for new theories of landowner decision making and behavior.

  10. Enhancing technological innovation in small firms: Role of collaboration

    NASA Astrophysics Data System (ADS)

    Singh, D.; Khamba, J. S.; Nanda, T.

    2014-07-01

    Contribution of Micro-Small and Medium Enterprises (MSMEs) is highly remarkable in the overall industrial economy of the country. In recent years, the MSME sector has consistently registered higher growth rate compared to the overall industrial sector. With its agility and dynamism, the sector has shown admirable innovativeness and adaptability to survive the recent economic downturn and recession. However, MSMEs growth rate is still at low level. Therefore, it becomes essential for organizations to adopt new technologies or upgrade existing setup to meet continuously changing global market and fulfill customer needs. This paper explores the relationships between different collaboration networks and technological innovation of small firms through an extensive review of literature. The study finds that collaboration with larger enterprises, R&D institutions, universities and government agencies play a significant role in enhancing technological innovation in small firms.

  11. e-SpaceCam : Development of a Remote Cooperative Observation System for Telescopes with P2P(Peer-to-Peer) Agent Network Using Location Information

    NASA Astrophysics Data System (ADS)

    Okamoto, T.; Kato, S.

    2006-08-01

    Introduction. It is very important for astronomical study and observation to operate a telescope by oneself. However, there are various problems such as the cost and location to use the telescope. The most promising technology that solves those problems is a remote telescope system. However, an old and usual remote telescope system was Server & Client type system. Therefore, the remote telescope owners and the remote telescope users have to manage their telescope by themselves. Especially, enough knowledge of the network, the time and cost to control the telescopes are necessary for the remote telescope owners. So it is difficult for general telescope owners to offer their telescopes as remote telescopes. We are developing a new environment that manages the remote telescopes. The environment connects users who want to use telescopes with the telescopes connected with PC (RS232c, USB, etc) all over the world. Our goal is to develop an environment by which users are able to cooperate and to share a lot of telescopes and the observational data for the education and the observation. Methods. Our remote telescope system is established on the P2P agent network. Various agents execute tasks allocated instead of users. (to retrieve, to connect, to control, etc) So users needn't do irksome tasks. Our system mounts LL-Net (Location-based Logical Network). LL-Net can manage user nodes on the P2P network by a key made based on location information. Our system key is allocated by the longitude and latitude. Results and Discussion. Users can retrieve remote telescopes that suit them and connect with them. Telescope owners can make their telescopes remote telescopes without troublesome jobs. Logical network constructed with LL-Net enables telescopes which the user hoped to be retrieved efficiently. We investigate more suitable use of LL-Net for a remote telescope. We plan to realize to share the observational data and to make remote telescopes cooperate.

  12. Incorporating GIS data into an agent-based model to support planning policy making for the development of creative industries

    NASA Astrophysics Data System (ADS)

    Liu, Helin; Silva, Elisabete A.; Wang, Qian

    2016-07-01

    This paper presents an extension to the agent-based model "Creative Industries Development-Urban Spatial Structure Transformation" by incorporating GIS data. Three agent classes, creative firms, creative workers and urban government, are considered in the model, and the spatial environment represents a set of GIS data layers (i.e. road network, key housing areas, land use). With the goal to facilitate urban policy makers to draw up policies locally and optimise the land use assignment in order to support the development of creative industries, the improved model exhibited its capacity to assist the policy makers conducting experiments and simulating different policy scenarios to see the corresponding dynamics of the spatial distributions of creative firms and creative workers across time within a city/district. The spatiotemporal graphs and maps record the simulation results and can be used as a reference by the policy makers to adjust land use plans adaptively at different stages of the creative industries' development process.

  13. Use of caries preventive agents on adult patients compared to pediatric patients by general practitioners: findings from The Dental Practice-Based Research Network

    PubMed Central

    Riley, Joseph L.; Gordan, Valeria V.; Rindal, D. Brad; Fellows, Jeffrey L.; Williams, O. Dale; Ritchie, Lloyd K.; Gilbert, Gregg H.

    2010-01-01

    Background Evidence suggests that caries prevention reduces caries in adults. This study tested the frequency of recommended caries prevention agents for children compared to adult patients. Methods This study surveyed 467 Dental Practice-Based Research Network general dentists who practice within the United States and treat both pediatric and adult patients. Dentists were asked the percentage of their patients who are administered or recommended dental sealants, in-office and at-home fluoride, chlorhexidine rinse, and xylitol gum. Results Adults were less likely to receive in-office caries preventive agents compared to pediatric patients. However, the rate of recommendation for at-home preventive regimens was very similar. Dentists with a conservative approach to caries treatment were the most likely to use caries prevention at similar rates in adults as in children. In addition, practices with a greater number of patients with dental insurance were significantly less likely to provide in-office fluoride or sealants to adult patients than to their pediatric patients. Conclusion In-office caries prevention agents are more commonly used by general dentists for their pediatric patients compared to their adult patients. Practice Implications Some general dentists should consider providing additional in-office prevention agents for their adult patients who are at increased risk for dental caries. PMID:20516100

  14. Bipartite output consensus in networked multi-agent systems of high-order power integrators with signed digraph and input noises

    NASA Astrophysics Data System (ADS)

    Ma, Hongwen; Liu, Derong; Wang, Ding; Luo, Biao

    2016-10-01

    In this paper, we concentrate on investigating bipartite output consensus in networked multi-agent systems of high-order power integrators. Systems with power integrator are ubiquitous among weakly coupled, unstable and underactuated mechanical systems. In the presence of input noises, an adaptive disturbance compensator and a technique of adding power integrator are introduced to the complex nonlinear multi-agent systems to reduce the deterioration of system performance. Additionally, due to the existence of negative communication weights among agents, whether bipartite output consensus of high-order power integrators can be achieved remains unknown. Therefore, it is of great importance to study this issue. The underlying idea of designing the distributed controller is to combine the output information of each agent itself and its neighbours, the state feedback within its internal system and input adaptive noise compensator all together. When the signed digraph is structurally balanced, bipartite output consensus can be reached. Finally, numerical simulations are provided to verify the validity of the developed criteria.

  15. Electronic Commerce, Digital Information, and the Firm.

    ERIC Educational Resources Information Center

    Rosenbaum, Howard

    2000-01-01

    Discussion of the social context of electronic commerce (ecommerce) focuses on information imperatives, or rules that are critical for ecommerce firms. Concludes with a discussion of the organizational changes that can be expected to accompany the incorporation of these imperatives into the mission and core business processes of ecommerce firms.…

  16. Theoretical Perspectives on the Internationalization of Firms

    ERIC Educational Resources Information Center

    Rask, Morten; Strandskov, Jesper; Hakonsson, Dorthe Dojbak

    2008-01-01

    The purpose of this article is to build a coherent framework of the four main theories relating to the internationalization of firms, in order to facilitate better business teaching and research. Yet, theories of the internationalization of firms are broad and rest on different underlying assumptions. With the purpose of clarifying the potential…

  17. 7 CFR 51.1012 - Fairly firm.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE REGULATIONS AND STANDARDS UNDER THE AGRICULTURAL MARKETING ACT OF 1946... Standards for Persian (Tahiti) Limes Definitions § 51.1012 Fairly firm. Fairly firm means that the fruit...

  18. 7 CFR 51.1551 - Firm.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE REGULATIONS AND STANDARDS UNDER THE AGRICULTURAL MARKETING ACT OF 1946... Standards for Grades of Potatoes 1 Definitions § 51.1551 Firm. Firm means that the potato is not...

  19. 7 CFR 51.1006 - Firm.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE REGULATIONS AND STANDARDS UNDER THE AGRICULTURAL MARKETING ACT OF 1946... Standards for Persian (Tahiti) Limes Definitions § 51.1006 Firm. Firm means that the fruit is not soft...

  20. Electronic Commerce, Digital Information, and the Firm.

    ERIC Educational Resources Information Center

    Rosenbaum, Howard

    2000-01-01

    Discussion of the social context of electronic commerce (ecommerce) focuses on information imperatives, or rules that are critical for ecommerce firms. Concludes with a discussion of the organizational changes that can be expected to accompany the incorporation of these imperatives into the mission and core business processes of ecommerce firms.…

  1. 7 CFR 51.3204 - Fairly firm.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE REGULATIONS AND STANDARDS UNDER THE AGRICULTURAL MARKETING ACT OF 1946... § 51.3204 Fairly firm. Fairly firm means that the onion may yield slightly to moderate pressure but...

  2. 7 CFR 51.893 - Firm.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE REGULATIONS AND STANDARDS UNDER THE AGRICULTURAL MARKETING ACT OF 1946... Definitions § 51.893 Firm. Firm means that the berry does not yield more than slightly to moderate...

  3. 7 CFR 51.3204 - Fairly firm.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE REGULATIONS AND STANDARDS UNDER THE AGRICULTURAL MARKETING ACT OF 1946... § 51.3204 Fairly firm. Fairly firm means that the onion may yield slightly to moderate pressure but...

  4. 7 CFR 51.893 - Firm.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE REGULATIONS AND STANDARDS UNDER THE AGRICULTURAL MARKETING ACT OF 1946... Definitions § 51.893 Firm. Firm means that the berry does not yield more than slightly to moderate...

  5. 7 CFR 51.2843 - Fairly firm.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE REGULATIONS AND STANDARDS UNDER THE AGRICULTURAL MARKETING ACT OF 1946... Creole Types) Definitions § 51.2843 Fairly firm. Fairly firm means that the onion may yield slightly...

  6. 7 CFR 51.2843 - Fairly firm.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE REGULATIONS AND STANDARDS UNDER THE AGRICULTURAL MARKETING ACT OF 1946... Fairly firm. Fairly firm means that the onion may yield slightly to moderate pressure but is...

  7. 7 CFR 51.2843 - Fairly firm.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE REGULATIONS AND STANDARDS UNDER THE AGRICULTURAL MARKETING ACT OF 1946... Creole Types) Definitions § 51.2843 Fairly firm. Fairly firm means that the onion may yield slightly...

  8. 32 CFR 37.1250 - Commercial firm.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 32 National Defense 1 2011-07-01 2011-07-01 false Commercial firm. 37.1250 Section 37.1250... REGULATIONS TECHNOLOGY INVESTMENT AGREEMENTS Definitions of Terms Used in This Part § 37.1250 Commercial firm... does a substantial portion of its business in the commercial marketplace....

  9. 24 CFR 200.47 - Firm commitments.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... DEVELOPMENT GENERAL INTRODUCTION TO FHA PROGRAMS Requirements for Application, Commitment, and Endorsement... Eligibility Requirements for Existing Projects Commitment Applications § 200.47 Firm commitments. A valid firm... completion of construction or substantial rehabilitation of the project; or (2) Upon completion of...

  10. A Firm Venture for a Public College.

    ERIC Educational Resources Information Center

    Hershfield, Allan F.

    1998-01-01

    The Fashion Institute of Technology (New York) is developing a Center for Design Innovation to nurture start-up of design firms and facilitate contacts between firms and clothing manufacturers, but its primary purpose is to generate revenue for the college. The evolution of the center and the lessons learned that may be useful to other public…

  11. Objectives of the Airline Firm: Theory

    NASA Technical Reports Server (NTRS)

    Kneafsey, J. T.

    1972-01-01

    Theoretical models are formulated for airline firm operations that revolve around alternative formulations of managerial goals which these firms are persuing in practice. Consideration is given to the different objective functions which the companies are following in lieu of profit maximization.

  12. On the topological structure of multinationals network

    NASA Astrophysics Data System (ADS)

    Joyez, Charlie

    2017-05-01

    This paper uses a weighted network analysis to examine the structure of multinationals' implantation countries network. Based on French firm-level dataset of multinational enterprises (MNEs) the network analysis provides information on each country position in the network and in internationalization strategies of French MNEs through connectivity preferences among the nodes. The paper also details network-wide features and their recent evolution toward a more decentralized structure. While much has been said on international trade network, this paper shows that multinational firms' studies would also benefit from network analysis, notably by investigating the sensitivity of the network construction to firm heterogeneity.

  13. Reference pricing and firms' pricing strategies.

    PubMed

    Miraldo, Marisa

    2009-01-01

    Within a horizontal differentiation model and allowing for heterogeneous qualities, we analyze the effects of reference pricing reimbursement on firms' pricing strategies. With this analysis we find inherent incentives for firms' pricing behavior, and consequently we shed some light on the time consistency of such policy. The analysis encompasses different reference price rules: (i) reference price as the minimum of the observed prices in the market, (ii) reference price as a linear combination of firms' prices. Results show that under the "minimum policy" firms are not able to coordinate on higher prices while the "linear policy", implicitly, provides a coordination device. We have also found that, relatively to the "linear policy", when the reference price is the minimum of observed prices, after policy implementation, total and private expenditures are higher and consumer surplus and firms' profits are lower. With quality differentiation both the minimum and linear policies unambiguously lead to higher prices.

  14. Competitive allocation of resources on a network: an agent-based model of air companies competing for the best routes

    NASA Astrophysics Data System (ADS)

    Gurtner, Gérald; Valori, Luca; Lillo, Fabrizio

    2015-05-01

    We present a stylized model of the allocation of resources on a network. By considering as a concrete example the network of sectors of the airspace, where each node is a sector characterized by a maximal number of simultaneously present aircraft, we consider the problem of air companies competing for the allocation of the airspace. Each company is characterized by a cost function, weighting differently punctuality and length of the flight. We consider the model in the presence of pure and mixed populations of types of airline companies and we study how the equilibria depends on the characteristics of the network.

  15. Driver-centred vehicle automation: using network analysis for agent-based modelling of the driver in highly automated driving systems.

    PubMed

    Banks, Victoria A; Stanton, Neville A

    2016-11-01

    To the average driver, the concept of automation in driving infers that they can become completely 'hands and feet free'. This is a common misconception, however, one that has been shown through the application of Network Analysis to new Cruise Assist technologies that may feature on our roads by 2020. Through the adoption of a Systems Theoretic approach, this paper introduces the concept of driver-initiated automation which reflects the role of the driver in highly automated driving systems. Using a combination of traditional task analysis and the application of quantitative network metrics, this agent-based modelling paper shows how the role of the driver remains an integral part of the driving system implicating the need for designers to ensure they are provided with the tools necessary to remain actively in-the-loop despite giving increasing opportunities to delegate their control to the automated subsystems. Practitioner Summary: This paper describes and analyses a driver-initiated command and control system of automation using representations afforded by task and social networks to understand how drivers remain actively involved in the task. A network analysis of different driver commands suggests that such a strategy does maintain the driver in the control loop.

  16. Detection of a nerve agent simulant using single-walled carbon nanotube networks: dimethyl-methyl-phosphonate.

    PubMed

    Kim, Yeonju; Lee, Seunghyun; Choi, Hyang Hee; Noh, Jin-Seo; Lee, Wooyoung

    2010-12-10

    Single-walled carbon nanotube (SWNT) networks were used to detect hazardous dimethyl-methyl-phosphonate (DMMP) gas in real time, employing two different metals as electrodes. Random networks of SWNTs were simply obtained by drop-casting a SWNT-containing solution onto a surface-oxidized Si substrate. Although the electrical responses to DMMP at room temperature were reversible for both metals, the Pd-contacting SWNT network sensors exhibited a higher response and a shorter response time than those of the Au-contacting SWNT network sensors at the same DMMP concentration, due to the stronger interactions between the SWNTs and Pd surface atoms. In Pd-contacting SWNT network sensors, the response increased linearly with increasing DMMP concentration and reproducible response curves were obtained for DMMP levels as low as 1 ppm. These results indicate that SWNT networks in contact with Pd electrodes can function as good DMMP sensors at room temperature with scalable and fast response and excellent recovery.

  17. Detection of a nerve agent simulant using single-walled carbon nanotube networks: dimethyl-methyl-phosphonate

    NASA Astrophysics Data System (ADS)

    Kim, Yeonju; Lee, Seunghyun; Choi, Hyang Hee; Noh, Jin-Seo; Lee, Wooyoung

    2010-12-01

    Single-walled carbon nanotube (SWNT) networks were used to detect hazardous dimethyl-methyl-phosphonate (DMMP) gas in real time, employing two different metals as electrodes. Random networks of SWNTs were simply obtained by drop-casting a SWNT-containing solution onto a surface-oxidized Si substrate. Although the electrical responses to DMMP at room temperature were reversible for both metals, the Pd-contacting SWNT network sensors exhibited a higher response and a shorter response time than those of the Au-contacting SWNT network sensors at the same DMMP concentration, due to the stronger interactions between the SWNTs and Pd surface atoms. In Pd-contacting SWNT network sensors, the response increased linearly with increasing DMMP concentration and reproducible response curves were obtained for DMMP levels as low as 1 ppm. These results indicate that SWNT networks in contact with Pd electrodes can function as good DMMP sensors at room temperature with scalable and fast response and excellent recovery.

  18. An Extended N-Player Network Game and Simulation of Four Investment Strategies on a Complex Innovation Network.

    PubMed

    Zhou, Wen; Koptyug, Nikita; Ye, Shutao; Jia, Yifan; Lu, Xiaolong

    2016-01-01

    As computer science and complex network theory develop, non-cooperative games and their formation and application on complex networks have been important research topics. In the inter-firm innovation network, it is a typical game behavior for firms to invest in their alliance partners. Accounting for the possibility that firms can be resource constrained, this paper analyzes a coordination game using the Nash bargaining solution as allocation rules between firms in an inter-firm innovation network. We build an extended inter-firm n-player game based on nonidealized conditions, describe four investment strategies and simulate the strategies on an inter-firm innovation network in order to compare their performance. By analyzing the results of our experiments, we find that our proposed greedy strategy is the best-performing in most situations. We hope this study provides a theoretical insight into how firms make investment decisions.

  19. An Extended N-Player Network Game and Simulation of Four Investment Strategies on a Complex Innovation Network

    PubMed Central

    Zhou, Wen; Koptyug, Nikita; Ye, Shutao; Jia, Yifan; Lu, Xiaolong

    2016-01-01

    As computer science and complex network theory develop, non-cooperative games and their formation and application on complex networks have been important research topics. In the inter-firm innovation network, it is a typical game behavior for firms to invest in their alliance partners. Accounting for the possibility that firms can be resource constrained, this paper analyzes a coordination game using the Nash bargaining solution as allocation rules between firms in an inter-firm innovation network. We build an extended inter-firm n-player game based on nonidealized conditions, describe four investment strategies and simulate the strategies on an inter-firm innovation network in order to compare their performance. By analyzing the results of our experiments, we find that our proposed greedy strategy is the best-performing in most situations. We hope this study provides a theoretical insight into how firms make investment decisions. PMID:26745375

  20. Single-agent maintenance therapy for advanced non-small cell lung cancer (NSCLC): a systematic review and Bayesian network meta-analysis of 26 randomized controlled trials

    PubMed Central

    Zeng, Xiaoning; Ma, Yuan

    2016-01-01

    Background The benefit of maintenance therapy has been confirmed in patients with non-progressing non-small cell lung cancer (NSCLC) after first-line therapy by many trials and meta-analyses. However, since few head-to-head trials between different regimens have been reported, clinicians still have little guidance on how to select the most efficacious single-agent regimen. Hence, we present a network meta-analysis to assess the comparative treatment efficacy of several single-agent maintenance therapy regimens for stage III/IV NSCLC. Methods A comprehensive literature search of public databases and conference proceedings was performed. Randomized clinical trials (RCTs) meeting the eligible criteria were integrated into a Bayesian network meta-analysis. The primary outcome was overall survival (OS) and the secondary outcome was progression free survival (PFS). Results A total of 26 trials covering 7,839 patients were identified, of which 24 trials were included in the OS analysis, while 23 trials were included in the PFS analysis. Switch-racotumomab-alum vaccine and switch-pemetrexed were identified as the most efficacious regimens based on OS (HR, 0.64; 95% CrI, 0.45–0.92) and PFS (HR, 0.54; 95% CrI, 0.26–1.04) separately. According to the rank order based on OS, switch-racotumomab-alum vaccine had the highest probability as the most effective regimen (52%), while switch-pemetrexed ranked first (34%) based on PFS. Conclusions Several single-agent maintenance therapy regimens can prolong OS and PFS for stage III/IV NSCLC. Switch-racotumomab-alum vaccine maintenance therapy may be the most optimal regimen, but should be confirmed by additional evidence. PMID:27781159

  1. Firms navigating through innovation spaces: a conceptualization of how firms search and perceive technological, market and productive opportunities globally.

    PubMed

    McKelvey, Maureen

    2016-01-01

    The main contribution of this paper is a theory-based conceptual framework of innovation spaces, and how firms must navigate through them to innovate. The concept of innovation systems - at the regional, sectoral and national levels - have been highly influential. Previous literature developing the concept of innovation systems has stressed the importance of institutions, networks and knowledge bases at the regional, sectoral and national levels. This paper primarily draws upon an evolutionary and Schumpeterian economics perspective, in the following three senses. The conceptualization of 'innnovation spaces' focuses upon how and why firm search for innovations is influenced the opportunities within certain geographical contexts. This means that the firm create opportunities and can span different context, but they are influence by the context in term of the access, flow and co-evolution of ideas, resources, technology, people and knowledge, which help stimulate business innovation in terms of products, process and services. The paper concludes with an agenda for future research and especially the need to focus on globalization as a process of intensifying linkages across the globe.

  2. Privatization and Entry of a Foreign Firm with Demand Uncertainty

    NASA Astrophysics Data System (ADS)

    Ferreira, Fernanda A.

    2009-09-01

    We investigate the effects of trade with a foreign firm and privatization of the domestic public firm on an incentive for the domestic firm to reduce costs by undertaking R&D investment, under demand uncertainty. We suppose that the domestic firm is less efficient than the foreign firm. However, the domestic firm can lower its marginal costs by conducting cost-reducing R&D investment. We examine the impacts of entry of a foreign firm, and the effects of demand uncertainty, on decisions upon cost-reducing R&D investment by the domestic firm and how these affect the domestic welfare.

  3. Enhanced Deployment Strategy for Role-Based Hierarchical Application Agents in Wireless Sensor Networks with Established Clusterheads

    ERIC Educational Resources Information Center

    Gendreau, Audrey

    2014-01-01

    Efficient self-organizing virtual clusterheads that supervise data collection based on their wireless connectivity, risk, and overhead costs, are an important element of Wireless Sensor Networks (WSNs). This function is especially critical during deployment when system resources are allocated to a subsequent application. In the presented research,…

  4. Enhanced Deployment Strategy for Role-Based Hierarchical Application Agents in Wireless Sensor Networks with Established Clusterheads

    ERIC Educational Resources Information Center

    Gendreau, Audrey

    2014-01-01

    Efficient self-organizing virtual clusterheads that supervise data collection based on their wireless connectivity, risk, and overhead costs, are an important element of Wireless Sensor Networks (WSNs). This function is especially critical during deployment when system resources are allocated to a subsequent application. In the presented research,…

  5. ECONOMIC DEVELOPMENT THEORIES AND BUSINESS FIRM STRATEGIES,

    DTIC Science & Technology

    characteristic economic patterns also provide a basis for business firms to plan their policies for investment and other international business activities in relation to opportunities in different kinds of environments. (Author)

  6. Design firms shaken by utility deregulation

    SciTech Connect

    Korman, R.

    1994-04-11

    Deregulation of the US utility industry has wrought massive change in the engineering community. Power-plant design firms not only play with a livelier ball this spring, they`re playing an entirely new game.

  7. A-E Firm Bridges Color Barrier

    ERIC Educational Resources Information Center

    Edmunds, Jane

    1974-01-01

    An architectural-engineering firm has sponsored a seminar on professional careers for black students, started a speakers bureau and a work study program, and participated in curriculum critiques at colleges. (Author/MLF)

  8. 78 FR 70987 - Proxy Advisory Firm Roundtable

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-27

    ... From the Federal Register Online via the Government Publishing Office ] SECURITIES AND EXCHANGE COMMISSION Proxy Advisory Firm Roundtable AGENCY: Securities and Exchange Commission. ACTION: Notice of roundtable discussion; request for comment. SUMMARY: The Securities and Exchange Commission will host...

  9. External Causes of Small Construction Firm Failures

    DTIC Science & Technology

    1989-08-01

    reasons for non-management contractor failures. These interviews led to letters and some phone interviews with national surety associations as we! l as...Table C-4 * 14 * CONSTRUCTION FIRM LIABILITIES FOI LOWI NG FA I L UPF 2500 ..... 200 1500* 0 00 00 1954 190 1966 197 1978 1984 1957 1963 1969 1975 1981...payroll according to Mr. Randell Tanner of Huffines, Tanner, and Russell Incorporated a Georgia commercial insurance firm. --As if to negate contractor

  10. Networks.

    ERIC Educational Resources Information Center

    Maughan, George R.; Petitto, Karen R.; McLaughlin, Don

    2001-01-01

    Describes the connectivity features and options of modern campus communication and information system networks, including signal transmission (wire-based and wireless), signal switching, convergence of networks, and network assessment variables, to enable campus leaders to make sound future-oriented decisions. (EV)

  11. Comparative safety and effectiveness of long-acting inhaled agents for treating chronic obstructive pulmonary disease: a systematic review and network meta-analysis

    PubMed Central

    Tricco, Andrea C; Strifler, Lisa; Veroniki, Areti-Angeliki; Yazdi, Fatemeh; Khan, Paul A; Scott, Alistair; Ng, Carmen; Antony, Jesmin; Mrklas, Kelly; D'Souza, Jennifer; Cardoso, Roberta; Straus, Sharon E

    2015-01-01

    Objective To compare the safety and effectiveness of long-acting β-antagonists (LABA), long-acting antimuscarinic agents (LAMA) and inhaled corticosteroids (ICS) for managing chronic obstructive pulmonary disease (COPD). Setting Systematic review and network meta-analysis (NMA). Participants 208 randomised clinical trials (RCTs) including 134 692 adults with COPD. Interventions LABA, LAMA and/or ICS, alone or in combination, versus each other or placebo. Primary and secondary outcomes The proportion of patients with moderate-to-severe exacerbations. The number of patients experiencing mortality, pneumonia, serious arrhythmia and cardiovascular-related mortality (CVM) were secondary outcomes. Results NMA was conducted including 20 RCTs for moderate-to-severe exacerbations for 26 141 patients with an exacerbation in the past year. 32 treatments were effective versus placebo including: tiotropium, budesonide/formoterol, salmeterol, indacaterol, fluticasone/salmeterol, indacaterol/glycopyrronium, tiotropium/fluticasone/salmeterol and tiotropium/budesonide/formoterol. Tiotropium/budesonide/formoterol was most effective (99.2% probability of being the most effective according to the Surface Under the Cumulative RAnking (SUCRA) curve). NMA was conducted on mortality (88 RCTs, 97 526 patients); fluticasone/salmeterol was more effective in reducing mortality than placebo, formoterol and fluticasone alone, and was the most effective (SUCRA=71%). NMA was conducted on CVM (37 RCTs, 55 156 patients) and the following were safest: salmeterol versus each OF placebo, tiotropium and tiotropium (Soft Mist Inhaler (SMR)); fluticasone versus tiotropium (SMR); and salmeterol/fluticasone versus tiotropium and tiotropium (SMR). Triamcinolone acetonide was the most harmful (SUCRA=81%). NMA was conducted on pneumonia occurrence (54 RCTs, 61 551 patients). 24 treatments were more harmful, including 2 that increased risk of pneumonia versus placebo; fluticasone and fluticasone

  12. Inferring host specificity and network formation through agent-based models: tick-mammal interactions in Borneo.

    PubMed

    Wells, Konstans; O'Hara, Robert B; Pfeiffer, Martin; Lakim, Maklarin B; Petney, Trevor N; Durden, Lance A

    2013-06-01

    Patterns of host-parasite association are poorly understood in tropical forests. While we typically observe only snapshots of the diverse assemblages and interactions under variable conditions, there is a desire to make inferences about prevalence and host-specificity patterns. We studied the interaction of ticks with non-volant small mammals in forests of Borneo. We inferred the probability of species interactions from individual-level data in a multi-level Bayesian model that incorporated environmental covariates and advanced estimates for rarely observed species through model averaging. We estimated the likelihood of observing particular interaction frequencies under field conditions and a scenario of exhaustive sampling and examined the consequences for inferring host specificity. We recorded a total of 13 different tick species belonging to the five genera Amblyomma, Dermacentor, Haemaphysalis, Ixodes, and Rhipicephalus from a total of 37 different host species (Rodentia, Scandentia, Carnivora, Soricidae) on 237 out of 1,444 host individuals. Infestation probabilities revealed most variation across host species but less variation across tick species with three common rat and two tree shrew species being most heavily infested. Host species identity explained ca. 75 % of the variation in infestation probability and another 8-10 % was explained by local host abundance. Host traits and site-specific attributes had little explanatory power. Host specificity was estimated to be similarly low for all tick species, which were all likely to infest 34-37 host species if exhaustively sampled. By taking into consideration the hierarchical organization of individual interactions that may take place under variable conditions and that shape host-parasite networks, we can discern uncertainty and sampling bias from true interaction frequencies, whereas network attributes derived from observed values may lead to highly misleading results. Multi-level approaches may help to move

  13. Agent-Based Modelling with Wavelets and an Evolutionary Artificial Neural Network: Applications to CAC 40 Forecasting

    NASA Astrophysics Data System (ADS)

    Hayward, Serge

    Analysis of separate scales of a complex signal provides a valuable source of information, considering that different financial decisions occur at different scales. Wavelet transform decomposition of a complex time series into separate scales and their economic representation is a focus of this study. An evolutionary / artificial neural network (E/ANN) is used to learn the information at separate scales and combine it into meaningfully weighted structures. Potential applications of the proposed approach are in financial forecasting and trading strategies development based on individual preferences and trading styles.

  14. Comparative efficacy, acceptability, and tolerability of augmentation agents in treatment-resistant depression: systematic review and network meta-analysis.

    PubMed

    Zhou, Xinyu; Ravindran, Arun V; Qin, Bin; Del Giovane, Cinzia; Li, Qi; Bauer, Michael; Liu, Yiyun; Fang, Yiru; da Silva, Tricia; Zhang, Yuqing; Fang, Liang; Wang, Xiao; Xie, Peng

    2015-04-01

    To comparatively analyze the efficacy, acceptability, and tolerability of various augmentation agents in adult patients with treatment-resistant depression. An electronic literature search of PubMed, EMBASE, the Cochrane Library, Web of Science, EBSCO, PsycINFO, EAGLE, and NTIS for trials published up to December 2013 was conducted. Several clinical trial registry agencies and US Food and Drug Administration reports were also reviewed. No language, publication date, or publication status restrictions were imposed. Randomized controlled trials comparing 11 augmentation agents (aripiprazole, bupropion, buspirone, lamotrigine, lithium, methylphenidate, olanzapine, pindolol, quetiapine, risperidone, and thyroid hormone) with each other and with placebo for adult treatment-resistant depression were included. The proportion of patients who responded to treatment was defined as primary efficacy, and the proportion of all-cause discontinuation and side-effects discontinuation were respectively defined as acceptability and tolerability, which were assessed with odds ratios (ORs) and a Bayesian random-effects model with 95% credible intervals (CrIs). A total of 48 trials consisting of 6,654 participants were eligible. In terms of the primary efficacy, quetiapine (OR = 1.92; 95% CrI, 1.39-3.13), aripiprazole (OR = 1.85; 95% CrI, 1.27-2.27), thyroid hormone (OR = 1.84; 95% CrI, 1.06-3.56), and lithium (OR = 1.56; 95% CrI, 1.05-2.55) were significantly more effective than placebo. Sensitivity analyses indicated that efficacy estimates for aripiprazole and quetiapine were more robust than those for thyroid hormone and lithium. In terms of acceptability, no significant difference was found between active agents and placebo. In terms of tolerability, compared to placebo, quetiapine (OR = 3.85; 95% CrI, 1.92-8.33), olanzapine (OR = 3.36; 95% CrI, 1.60-8.61), aripiprazole (OR = 2.51; 95% CrI, 1.11-7.69), and lithium (OR = 2.30; 95% CrI, 1.04-6.03) were significantly less well

  15. Classification of the micro and nanoparticles and biological agents by neural network analysis of the parameters of optical resonance of whispering gallery mode in dielectric microspheres

    NASA Astrophysics Data System (ADS)

    Saetchnikov, Vladimir A.; Tcherniavskaia, Elina A.; Schweiger, Gustav; Ostendorf, Andreas

    2011-07-01

    A novel technique for the label-free analysis of micro and nanoparticles including biomolecules using optical micro cavity resonance of whispering-gallery-type modes is being developed. Various schemes of the method using both standard and specially produced microspheres have been investigated to make further development for microbial application. It was demonstrated that optical resonance under optimal geometry could be detected under the laser power of less 1 microwatt. The sensitivity of developed schemes has been tested by monitoring the spectral shift of the whispering gallery modes. Water solutions of ethanol, ascorbic acid, blood phantoms including albumin and HCl, glucose, biotin, biomarker like C reactive protein so as bacteria and virus phantoms (gels of silica micro and nanoparticles) have been used. Structure of resonance spectra of the solutions was a specific subject of investigation. Probabilistic neural network classifier for biological agents and micro/nano particles classification has been developed. Several parameters of resonance spectra as spectral shift, broadening, diffuseness and others have been used as input parameters to develop a network classifier for micro and nanoparticles and biological agents in solution. Classification probability of approximately 98% for probes under investigation have been achieved. Developed approach have been demonstrated to be a promising technology platform for sensitive, lab-on-chip type sensor which can be used for development of diagnostic tools for different biological molecules, e.g. proteins, oligonucleotides, oligosaccharides, lipids, small molecules, viral particles, cells as well as in different experimental contexts e.g. proteomics, genomics, drug discovery, and membrane studies.

  16. 48 CFR 1852.216-78 - Firm fixed price.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 6 2014-10-01 2014-10-01 false Firm fixed price. 1852.216... 1852.216-78 Firm fixed price. As prescribed in 1816.202-70, insert the following clause: Firm Fixed Price (DEC 1988) The total firm fixed price of this contract is $ . (End of clause) ...

  17. 48 CFR 1852.216-78 - Firm fixed price.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 6 2011-10-01 2011-10-01 false Firm fixed price. 1852.216... 1852.216-78 Firm fixed price. As prescribed in 1816.202-70, insert the following clause: Firm Fixed Price (DEC 1988) The total firm fixed price of this contract is $ . (End of clause) ...

  18. 48 CFR 1852.216-78 - Firm fixed price.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 6 2012-10-01 2012-10-01 false Firm fixed price. 1852.216... 1852.216-78 Firm fixed price. As prescribed in 1816.202-70, insert the following clause: Firm Fixed Price (DEC 1988) The total firm fixed price of this contract is $ . (End of clause) ...

  19. 48 CFR 1852.216-78 - Firm fixed price.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 6 2013-10-01 2013-10-01 false Firm fixed price. 1852.216... 1852.216-78 Firm fixed price. As prescribed in 1816.202-70, insert the following clause: Firm Fixed Price (DEC 1988) The total firm fixed price of this contract is $ . (End of clause) ...

  20. 48 CFR 1852.216-78 - Firm fixed price.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 6 2010-10-01 2010-10-01 true Firm fixed price. 1852.216... 1852.216-78 Firm fixed price. As prescribed in 1816.202-70, insert the following clause: Firm Fixed Price (DEC 1988) The total firm fixed price of this contract is $ . (End of clause) ...

  1. 46 CFR 201.22 - Firms and corporations.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 8 2010-10-01 2010-10-01 false Firms and corporations. 201.22 Section 201.22 Shipping... PROCEDURE Appearance and Practice Before the Administration (Rule 2) § 201.22 Firms and corporations. Except as regards law firms, practice before the Administration by firms or corporations on behalf of...

  2. Firm competition in a probabilistic framework of consumer choice

    NASA Astrophysics Data System (ADS)

    Liao, Hao; Xiao, Rui; Chen, Duanbing; Medo, Matúš; Zhang, Yi-Cheng

    2014-04-01

    We develop a probabilistic consumer choice framework based on information asymmetry between consumers and firms. This framework makes it possible to study market competition of several firms by both quality and price of their products. We find Nash market equilibria and other optimal strategies in various situations ranging from competition of two identical firms to firms of different sizes and firms which improve their efficiency.

  3. How small firms contrast with large firms regarding perceptions, practices, and needs in the U.S

    Treesearch

    Urs Buehlmann; Matthew Bumgardner; Michael. Sperber

    2013-01-01

    As many larger secondary woodworking firms have moved production offshore and been adversely impacted by the recent housing downturn, smaller firms have become important to driving U.S. hardwood demand. This study compared and contrasted small and large firms on a number of factors to help determine the unique characteristics of small firms and to provide insights into...

  4. The role of endogenous and exogenous mechanisms in the formation of R&D networks

    PubMed Central

    Tomasello, Mario V.; Perra, Nicola; Tessone, Claudio J.; Karsai, Márton; Schweitzer, Frank

    2014-01-01

    We develop an agent-based model of strategic link formation in Research and Development (R&D) networks. Empirical evidence has shown that the growth of these networks is driven by mechanisms which are both endogenous to the system (that is, depending on existing alliances patterns) and exogenous (that is, driven by an exploratory search for newcomer firms). Extant research to date has not investigated both mechanisms simultaneously in a comparative manner. To overcome this limitation, we develop a general modeling framework to shed light on the relative importance of these two mechanisms. We test our model against a comprehensive dataset, listing cross-country and cross-sectoral R&D alliances from 1984 to 2009. Our results show that by fitting only three macroscopic properties of the network topology, this framework is able to reproduce a number of micro-level measures, including the distributions of degree, local clustering, path length and component size, and the emergence of network clusters. Furthermore, by estimating the link probabilities towards newcomers and established firms from the data, we find that endogenous mechanisms are predominant over the exogenous ones in the network formation, thus quantifying the importance of existing structures in selecting partner firms. PMID:25022561

  5. The role of endogenous and exogenous mechanisms in the formation of R&D networks

    NASA Astrophysics Data System (ADS)

    Tomasello, Mario V.; Perra, Nicola; Tessone, Claudio J.; Karsai, Márton; Schweitzer, Frank

    2014-07-01

    We develop an agent-based model of strategic link formation in Research and Development (R&D) networks. Empirical evidence has shown that the growth of these networks is driven by mechanisms which are both endogenous to the system (that is, depending on existing alliances patterns) and exogenous (that is, driven by an exploratory search for newcomer firms). Extant research to date has not investigated both mechanisms simultaneously in a comparative manner. To overcome this limitation, we develop a general modeling framework to shed light on the relative importance of these two mechanisms. We test our model against a comprehensive dataset, listing cross-country and cross-sectoral R&D alliances from 1984 to 2009. Our results show that by fitting only three macroscopic properties of the network topology, this framework is able to reproduce a number of micro-level measures, including the distributions of degree, local clustering, path length and component size, and the emergence of network clusters. Furthermore, by estimating the link probabilities towards newcomers and established firms from the data, we find that endogenous mechanisms are predominant over the exogenous ones in the network formation, thus quantifying the importance of existing structures in selecting partner firms.

  6. The firm as a bundle of barcodes

    NASA Astrophysics Data System (ADS)

    Sakai, K.; Watanabe, T.

    2010-08-01

    We empirically investigate the firm growth model proposed by Buldyrev et al. by using a unique dataset that contains the daily sales of more than 200 thousand products, which are collected from about 200 supermarkets in Japan over the last 20 years. We find that the empirical firm growth distribution is characterized by a Laplace distribution at the center and power-law at the tails, as predicted by the model. However, some of these characteristics disappear once we randomly reshuffle products across firms, implying that the shape of the empirical distribution is not produced as described by the model. Our simulation results suggest that the shape of the empirical distribution stems mainly from the presence of relationship between the size of a product and its growth rate.

  7. Comparative efficacy and safety of blood pressure-lowering agents in adults with diabetes and kidney disease: a network meta-analysis.

    PubMed

    Palmer, Suetonia C; Mavridis, Dimitris; Navarese, Eliano; Craig, Jonathan C; Tonelli, Marcello; Salanti, Georgia; Wiebe, Natasha; Ruospo, Marinella; Wheeler, David C; Strippoli, Giovanni F M

    2015-05-23

    The comparative efficacy and safety of pharmacological agents to lower blood pressure in adults with diabetes and kidney disease remains controversial. We aimed to investigate the benefits and harms of blood pressure-lowering drugs in this population of patients. We did a network meta-analysis of randomised trials from around the world comparing blood pressure-lowering agents in adults with diabetic kidney disease. Electronic databases (the Cochrane Collaboration, Medline, and Embase) were searched systematically up to January, 2014, for trials in adults with diabetes and kidney disease comparing orally administered blood pressure-lowering drugs. Primary outcomes were all-cause mortality and end-stage kidney disease. We also assessed secondary safety and cardiovascular outcomes. We did random-effects network meta-analysis to obtain estimates for primary and secondary outcomes and we presented these estimates as odds ratios or standardised mean differences with 95% CIs. We ranked the comparative effects of all drugs against placebo with surface under the cumulative ranking (SUCRA) probabilities. 157 studies comprising 43,256 participants, mostly with type 2 diabetes and chronic kidney disease, were included in the network meta-analysis. No drug regimen was more effective than placebo for reducing all-cause mortality. However, compared with placebo, end-stage renal disease was significantly less likely after dual treatment with an angiotensin-receptor blocker (ARB) and an angiotensin-converting-enzyme (ACE) inhibitor (odds ratio 0·62, 95% CI 0·43-0·90) and after ARB monotherapy (0·77, 0·65-0·92). No regimen significantly increased hyperkalaemia or acute kidney injury, although combined ACE inhibitor and ARB treatment had the lowest rank among all interventions because of borderline increases in estimated risks of these harms (odds ratio 2·69, 95% CI 0·97-7·47 for hyperkalaemia; 2·69, 0·98-7·38 for acute kidney injury). No blood pressure-lowering strategy

  8. Beefing up operations in service firms.

    PubMed

    Chase, R B; Hayes, R H

    1991-01-01

    Many articles exhort service firm managers to empower workers and first-line supervisors, exploit technology, focus on the customer, and, above all, provide outstanding service. This article proposes a framework to help you evaluate your company's competitive standing in each of these areas. It discusses four types of companies on a continuum, from the company that is simply "available for service" to the firm that delivers world class service. The authors focus on operations, the function that controls the service encounter, and apply the manufacturing strategy paradigm to services as a means of implementing change.

  9. Firm size diversity, functional richness, and resilience

    USGS Publications Warehouse

    Garmestani, A.S.; Allen, C.R.; Mittelstaedt, J.D.; Stow, C.A.; Ward, W.A.

    2006-01-01

    This paper applies recent advances in ecology to our understanding of firm development, sustainability, and economic development. The ecological literature indicates that the greater the functional richness of species in a system, the greater its resilience - that is, its ability to persist in the face of substantial changes in the environment. This paper focuses on the effects of functional richness across firm size on the ability of industries to survive in the face of economic change. Our results indicate that industries with a richness of industrial functions are more resilient to employment volatility. ?? 2006 Cambridge University Press.

  10. Ontology-Based Model Of Firm Competitiveness

    NASA Astrophysics Data System (ADS)

    Deliyska, Boryana; Stoenchev, Nikolay

    2010-10-01

    Competitiveness is important characteristics of each business organization (firm, company, corporation etc). It is of great significance for the organization existence and defines evaluation criteria of business success at microeconomical level. Each criterium comprises set of indicators with specific weight coefficients. In the work an ontology-based model of firm competitiveness is presented as a set of several mutually connected ontologies. It would be useful for knowledge structuring, standardization and sharing among experts and software engineers who develop application in the domain. Then the assessment of the competitiveness of various business organizations could be generated more effectively.

  11. Networking.

    ERIC Educational Resources Information Center

    Duvall, Betty

    Networking is an information giving and receiving system, a support system, and a means whereby women can get ahead in careers--either in new jobs or in current positions. Networking information can create many opportunities: women can talk about how other women handle situations and tasks, and previously established contacts can be used in…

  12. Colleagues as Change Agents: How Department Networks and Opinion Leaders Influence Teaching at a Single Research University

    PubMed Central

    Andrews, T. C.; Conaway, E. P.; Zhao, J.; Dolan, E. L.

    2016-01-01

    Relationships with colleagues have the potential to be a source of support for faculty to make meaningful change in how they teach, but the impact of these relationships is poorly understood. We used a mixed-methods approach to investigate the characteristics of faculty who provide colleagues with teaching resources and facilitate change in teaching, how faculty influence one another. Our exploratory investigation was informed by social network theory and research on the impact of opinion leaders within organizations. We used surveys and interviews to examine collegial interactions about undergraduate teaching in life sciences departments at one research university. Each department included discipline-based education researchers (DBERs). Quantitative and qualitative analyses indicate that DBERs promote changes in teaching to a greater degree than other departmental colleagues. The influence of DBERs derives, at least partly, from a perception that they have unique professional expertise in education. DBERs facilitated change through coteaching, offering ready and approachable access to education research, and providing teaching training and mentoring. Faculty who had participated in a team based–teaching professional development program were also credited with providing more support for teaching than nonparticipants. Further research will be necessary to determine whether these results generalize beyond the studied institution. PMID:27174582

  13. 40 CFR 745.89 - Firm certification.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Firm certification. 745.89 Section 745.89 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT LEAD-BASED PAINT POISONING PREVENTION IN CERTAIN RESIDENTIAL STRUCTURES Residential Property...

  14. 40 CFR 745.89 - Firm certification.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Firm certification. 745.89 Section 745.89 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT LEAD-BASED PAINT POISONING PREVENTION IN CERTAIN RESIDENTIAL STRUCTURES Residential Property...

  15. 40 CFR 745.89 - Firm certification.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Firm certification. 745.89 Section 745.89 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT LEAD-BASED PAINT POISONING PREVENTION IN CERTAIN RESIDENTIAL STRUCTURES Residential Property...

  16. 40 CFR 745.89 - Firm certification.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Firm certification. 745.89 Section 745.89 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT LEAD-BASED PAINT POISONING PREVENTION IN CERTAIN RESIDENTIAL STRUCTURES Residential Property...

  17. 24 CFR 200.47 - Firm commitments.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... DEVELOPMENT GENERAL INTRODUCTION TO FHA PROGRAMS Requirements for Application, Commitment, and Endorsement... 24 Housing and Urban Development 2 2010-04-01 2010-04-01 false Firm commitments. 200.47 Section 200.47 Housing and Urban Development Regulations Relating to Housing and Urban Development (Continued...

  18. High Performance Work Practices and Firm Performance.

    ERIC Educational Resources Information Center

    Department of Labor, Washington, DC. Office of the American Workplace.

    A literature survey established that a substantial amount of research has been conducted on the relationship between productivity and the following specific high performance work practices: employee involvement in decision making, compensation linked to firm or worker performance, and training. According to these studies, high performance work…

  19. On size and growth of business firms

    NASA Astrophysics Data System (ADS)

    De Fabritiis, G.; Pammolli, F.; Riccaboni, M.

    2003-06-01

    We study size and growth distributions of products and business firms in the context of a given industry. Firm size growth is analyzed in terms of two basic mechanisms, i.e., the increase of the number of new elementary business units and their size growth. We find a power-law relationship between size and the variance of growth rates for both firms and products, with an exponent between -0.17 and -0.15, with a remarkable stability upon aggregation. We then introduce a simple and general model of proportional growth for both the number of firm independent constituent units and their size, which conveys a good representation of the empirical evidences. This general and plausible generative process can account for the observed scaling in a wide variety of economic and industrial systems. Our findings contribute to shed light on the mechanisms that sustain economic growth in terms of the relationships between the size of economic entities and the number and size distribution of their elementary components.

  20. Textile firm converts to wood fuel

    SciTech Connect

    Not Available

    1980-06-01

    The successful conversion in a textile firm from using oil and gas fired boilers to wood is described. The use of wood waste saved $2.50 per million Btu over what it would cost to burn it and the $2.7 million investment has almost paid for itself after four years of operation.

  1. Colleagues as Change Agents: How Department Networks and Opinion Leaders Influence Teaching at a Single Research University.

    PubMed

    Andrews, T C; Conaway, E P; Zhao, J; Dolan, E L

    2016-01-01

    Relationships with colleagues have the potential to be a source of support for faculty to make meaningful change in how they teach, but the impact of these relationships is poorly understood. We used a mixed-methods approach to investigate the characteristics of faculty who provide colleagues with teaching resources and facilitate change in teaching, how faculty influence one another. Our exploratory investigation was informed by social network theory and research on the impact of opinion leaders within organizations. We used surveys and interviews to examine collegial interactions about undergraduate teaching in life sciences departments at one research university. Each department included discipline-based education researchers (DBERs). Quantitative and qualitative analyses indicate that DBERs promote changes in teaching to a greater degree than other departmental colleagues. The influence of DBERs derives, at least partly, from a perception that they have unique professional expertise in education. DBERs facilitated change through coteaching, offering ready and approachable access to education research, and providing teaching training and mentoring. Faculty who had participated in a team based-teaching professional development program were also credited with providing more support for teaching than nonparticipants. Further research will be necessary to determine whether these results generalize beyond the studied institution. © 2016 T. C. Andrews et al. CBE—Life Sciences Education © 2016 The American Society for Cell Biology. This article is distributed by The American Society for Cell Biology under license from the author(s). It is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).

  2. A Systematic Review and Network Meta-Analysis of Biologic Agents in the First Line Setting for Advanced Colorectal Cancer

    PubMed Central

    Kumachev, Alexander; Yan, Marie; Berry, Scott; Ko, Yoo-Joung; Martinez, Maria C. R.; Shah, Keya; Chan, Kelvin K. W.

    2015-01-01

    Background Epithelial growth factor receptor inhibitors (EGFRis) and bevacizumab (BEV) are used in combination with chemotherapy for the treatment of metastatic colorectal cancer (mCRC). However, few randomized controlled trials (RCTs) have directly compared their relative efficacy on progression-free survival (PFS) and overall survival (OS). Methods We conducted a systematic review of first-line RCTs comparing (1) EGFRis vs. BEV, with chemotherapy in both arms (2) EGFRis + chemotherapy vs. chemotherapy alone, or (3) BEV + chemotherapy vs. chemotherapy alone, using Cochrane methodology. Data on and PFS and OS were extracted using the Parmar method. Pairwise meta-analyses and Bayesian network meta-analyses (NMA) were conducted to estimate the direct, indirect and combined PFS and OS hazard ratios (HRs) comparing EGFRis to BEV. Results Seventeen RCTs contained extractable data for quantitative analysis. Combining direct and indirect data using an NMA did not show a statistical difference between EGFRis versus BEV (PFS HR = 1.11 (95% CR: 0.92–1.36) and OS HR = 0.91 (95% CR: 0.75–1.09)). Direct meta-analysis (3 RCTs), indirect (14 RCTs) and combined (17 RCTs) NMA of PFS HRs were concordant and did not show a difference between EGFRis and BEV. Meta-analysis of OS using direct evidence, largely influenced by one trial, showed an improvement with EGFRis therapy (HR = 0.79 (95% CR: 0.65–0.98)), while indirect and combined NMA of OS did not show a difference between EGFRis and BEV Successive inclusions of trials over time in the combined NMA did not show superiority of EGFRis over BEV. Conclusions Our findings did not support OS or PFS benefits of EGFRis over BEV in first-line mCRC. PMID:26474403

  3. Systematic review and network meta-analysis comparing antithrombotic agents for the prevention of stroke and major bleeding in patients with atrial fibrillation

    PubMed Central

    Cameron, Chris; Coyle, Doug; Richter, Trevor; Kelly, Shannon; Gauthier, Kasandra; Steiner, Sabine; Carrier, Marc; Coyle, Kathryn; Bai, Annie; Moulton, Kristen; Clifford, Tammy; Wells, George

    2014-01-01

    Objective To examine the comparative efficacy and safety of antithrombotic treatments (apixaban, dabigatran, edoxaban, rivaroxaban and vitamin K antagonists (VKA) at a standard adjusted dose (target international normalised ratio 2.0–3.0), acetylsalicylic acid (ASA), ASA and clopidogrel) for non-valvular atrial fibrillation and among subpopulations. Design Systematic review and network meta-analysis. Data sources A systematic literature search strategy was designed and carried out using MEDLINE, EMBASE, the Cochrane Register of Controlled Trials and the grey literature including the websites of regulatory agencies and health technology assessment organisations for trials published in English from 1988 to January 2014. Eligibility criteria for selecting studies Randomised controlled trials were selected for inclusion if they were published in English, included at least one antithrombotic treatment and involved patients with non-valvular atrial fibrillation eligible to receive anticoagulant therapy. Results For stroke or systemic embolism, dabigatran 150 mg and apixaban twice daily were associated with reductions relative to standard adjusted dose VKA, whereas low-dose ASA and the combination of clopidogrel plus low-dose ASA were associated with increases. Absolute risk reductions ranged from 6 fewer events per 1000 patients treated for dabigatran 150 mg twice daily to 15 more events for clopidogrel plus ASA. For major bleeding, edoxaban 30 mg daily, apixaban, edoxaban 60 mg daily and dabigatran 110 mg twice daily were associated with reductions compared to standard adjusted dose VKA. Absolute risk reductions with these agents ranged from 18 fewer per 1000 patients treated each year for edoxaban 30 mg daily to 24 more for medium dose ASA. Conclusions Compared with standard adjusted dose VKA, new oral anticoagulants were associated with modest reductions in the absolute risk of stroke and major bleeding. People on antiplatelet drugs experienced more

  4. Microcap pharmaceutical firms: linking drug pipelines to market value.

    PubMed

    Beach, Robert

    2012-01-01

    This article examines predictors of the future market value of microcap pharmaceutical companies. This is problematic since the large majority of these firms seldom report positive net income. Their value comes from the potential of a liquidity event such as occurs when a key drug is approved by the FDA. The typical scenario is one in which the company is either acquired by a larger pharmaceutical firm or enters into a joint venture with another pharmaceutical firm. Binary logistic regression is used to determine the impact of the firm's drug treatment pipeline and its investment in research and development on the firm's market cap. Using annual financial data from 2007 through 2010, this study finds that the status of the firm's drug treatment pipeline and its research and development expenses are significant predictors of the firm's future stock value relative to other microcap pharmaceutical firms.

  5. Firm behavior, environmental externalities and public policy

    NASA Astrophysics Data System (ADS)

    Curtis, Earnest Markell, IV

    This dissertation consists of three essays which examine environmental policy, employer mandates and energy consumption. The essays explore how firms respond to government policies such as environmental regulation and employer mandates. Understanding how firms adjust to government policies is crucial to law makers attempting to design optimal policies that maximize net benefits to society. The first essay, titled Who Loses under Power Plant Cap-and-Trade Programs tests how a major cap-and-trade program, known as the NOx Budget Trading Program (NBP), affected labor markets in the region where it was implemented. The cap-and-trade program dramatically decreased levels of NOx emissions and added substantial costs to energy producers. Using a triple-differences approach that takes advantage of the geographic and time variation of the program as well as variation in industry energy-intensity levels, I examine how employment dynamics changed in manufacturing industries whose production process requires high levels of energy. After accounting for a variety of flexible state, county and industry trends, I find that employment in the manufacturing sector dropped by 1.7% as a result of the NBP. Young workers experienced the largest employment declines and earnings of newly hired workers fell after the regulation began. Employment declines are shown to have occurred primarily through decreased hiring rates rather than increased separation rates, thus mitigating the impact on incumbent workers. The second essay, titled Evaluating Workplace Mandates with Flows versus Stocks: An Application to California Paid Family Leave uses an underexploited data set to examine the impact of the California Paid Family Leave program on employment outcomes for young women. Most papers on mandated benefits examine labor outcomes by looking at earnings and employment levels of all workers. Examining these levels will be imprecise if the impacts of the program develop over time and firms are wary

  6. NASA cash boost for space firms

    NASA Astrophysics Data System (ADS)

    Gwynne, Peter

    2012-09-01

    NASA has awarded 1.1bn to three US firms to design and develop the "next generation of human spaceflight capabilities". Boeing, Sierra Nevada and Space Exploration Technologies (SpaceX), who will receive 460m, 212.5m and 440m respectively, will use the money to improve and test their systems intended to fly astronauts to the International Space Station (ISS) within the next five years.

  7. US firms leave business lobby group

    NASA Astrophysics Data System (ADS)

    Gwynne, Peter

    2009-11-01

    Three US energy and hi-tech firms have left the US Chamber of Commerce - a powerful group that lobbies on behalf of business - because it has openly questioned the science behind climate change. The departing organizations protest that the chamber and another business lobbying group, the National Association of Manufacturers (NAM), could cripple advances in renewable energy by becoming representatives of fossil-fuel interests.

  8. 77 FR 47820 - Invention Promoters/Promotion Firms Complaints

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-10

    ... United States Patent and Trademark Office Invention Promoters/Promotion Firms Complaints ACTION: Proposed... participate in any legal proceedings against invention promoters or promotion firms. Complaints submitted to... promotion firm, explain the basis for the complaint, and include the signature of the complainant....

  9. 18 CFR 284.7 - Firm transportation service.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 18 Conservation of Power and Water Resources 1 2014-04-01 2014-04-01 false Firm transportation... AUTHORITIES CERTAIN SALES AND TRANSPORTATION OF NATURAL GAS UNDER THE NATURAL GAS POLICY ACT OF 1978 AND RELATED AUTHORITIES General Provisions and Conditions § 284.7 Firm transportation service. (a) Firm...

  10. MBA for Small Firms and Microenterprises? Development Issues

    ERIC Educational Resources Information Center

    Lynch, Paul; Baty, Richard; Abdullah, Farouk; Seaman, Claire

    2005-01-01

    Purpose: To report on an investigation amongst small firm owner-managers in the service sector into potential demand for an MBA. Design/methodology/approach: Relevant recent literature is critiqued concerning small firms and learning, and MBAs and small firms. A description is given of the research methods employed involving a mail questionnaire…

  11. MBA for Small Firms and Microenterprises? Development Issues

    ERIC Educational Resources Information Center

    Lynch, Paul; Baty, Richard; Abdullah, Farouk; Seaman, Claire

    2005-01-01

    Purpose: To report on an investigation amongst small firm owner-managers in the service sector into potential demand for an MBA. Design/methodology/approach: Relevant recent literature is critiqued concerning small firms and learning, and MBAs and small firms. A description is given of the research methods employed involving a mail questionnaire…

  12. The Effects of Parental Firm Control: A Reinterpretation of Findings.

    ERIC Educational Resources Information Center

    Lewis, Catherine C.

    1981-01-01

    Evidence that parental firm control promotes effective socialization of children (i.e., promotes self-control, social responsibility) is examined, and a reinterpretation of existing measures of firm control that is consistent with attribution theory is offered. It is concluded that the notion that parental firm control promotes effective…

  13. 18 CFR 284.7 - Firm transportation service.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 18 Conservation of Power and Water Resources 1 2011-04-01 2011-04-01 false Firm transportation... AUTHORITIES CERTAIN SALES AND TRANSPORTATION OF NATURAL GAS UNDER THE NATURAL GAS POLICY ACT OF 1978 AND RELATED AUTHORITIES General Provisions and Conditions § 284.7 Firm transportation service. (a) Firm...

  14. Unbundled infrastructure firms: Competition and continuing regulation

    NASA Astrophysics Data System (ADS)

    Hogendorn, Christiaan Paul

    Unbundled infrastructure firms provide conduits for electricity transmission, residential communications, etc. but are vertically disintegrated from "content" functions such as electricity generation or world-wide-web pages. These conduits are being deregulated, and this dissertation examines whether the deregulated conduits will behave in an efficient and competitive manner. The dissertation presents three essays, each of which develops a theoretical model of the behavior of conduit firms in a market environment. The first essay considers the prospects for competition between multiple conduits in the emerging market for broadband (high-speed) residential Internet access. It finds that such competition is likely to emerge as demand for these services increase. The second essay shows how a monopoly electricity or natural gas transmission conduit can facilitate collusion between suppliers of the good. It shows that this is an inefficient effect of standard price-cap regulation. The third essay considers the supply chain of residential Internet access and evaluates proposed "open access" regulation that would allow more than one firm to serve customers over the same physical infrastructure. It shows that the amount of content available to consumers does not necessarily increase under open access.

  15. The New Agent: A Qualitative Study to Strategically Adapt New Agent Professional Development

    ERIC Educational Resources Information Center

    Baker, Lauri M.; Hadley, Gregg

    2014-01-01

    The qualitative study reported here assessed the needs of agents related to new agent professional development to improve the current model. Agents who participated in new agent professional development within the last 5 years were selected to participate in focus groups to determine concerns and continued needs. Agents enjoyed networking and…

  16. The New Agent: A Qualitative Study to Strategically Adapt New Agent Professional Development

    ERIC Educational Resources Information Center

    Baker, Lauri M.; Hadley, Gregg

    2014-01-01

    The qualitative study reported here assessed the needs of agents related to new agent professional development to improve the current model. Agents who participated in new agent professional development within the last 5 years were selected to participate in focus groups to determine concerns and continued needs. Agents enjoyed networking and…

  17. Statistical physics approaches to understanding the firm growth problem

    NASA Astrophysics Data System (ADS)

    Fu, Dongfeng

    This thesis applies statistical physics approaches to investigate quantitatively the size and growth of the complex system of business firms. We study the logarithm of the one-year growth rate of firms g ≡ log(S(t + 1)/S( t)) where S(t) and S( t + 1) are the sizes of firms in the year t and t + 1 measured in monetary values. Part I in this thesis reviews some main empirical results of firm size and firm growth based on different databases. They are (i) the size distribution of firms P(S) are found to be skewed (either log-normal or power-law depending on the different databases), (ii) the growth-rate distributions of firms P(g) are of Laplace form with power-law tails, (iii) the standard deviation of firm growth rates is related by a negative power-law to the firm size. The distribution of firm growth rates conditioned on firm size collapses onto a single curve, which implies that a universal functional form may exist to describe the distribution of firm growth rate. Part II models the Entry & Exit effect and firm proportional growth using a generalized preferential attachment model. The model assumes that a new firm enters the system with a constant rate; a new unit enters/exits one of existing firms preferentially, that it, the larger firms have bigger probability to obtain the new unit, and the larger firms have bigger probability to lose a unit. The model successfully explains the observations: (i) the distribution of unit number P( K) in a firm is power law with exponential tails, (ii) P (g) is of Laplace form with power-law tails with exponent 3. Part III studies the Merging & Splitting effect in the framework of Coase theory using a dynamic percolation model in a 2-dimensional lattice where each row represents a product and each column can represent a consumer; a cell is a potential transaction. The size of the firm would be represented by the number of the cells it covers in the lattice. The model explains the facts that P(S) is power-law, P(g) is tent

  18. Impacts of Transitioning from Firm Fixed Price to Fixed Price Incentive Firm Target Contracts in PEO Missiles and Space

    DTIC Science & Technology

    2016-09-01

    PRICE INCENTIVE FIRM TARGET CONTRACTS IN PEO MISSILES AND SPACE September 2016 By: Suzanne E. Makowski Brandi M. Ricketts Shannon M...SUBTITLE IMPACTS OF TRANSITIONING FROM FIRM FIXED PRICE TO FIXED PRICE INCENTIVE FIRM TARGET CONTRACTS IN PEO MISSILES AND SPACE 5. FUNDING NUMBERS 6...analyze the impacts to major weapon systems programs in Program Executive Office (PEO) Missiles and Space as a result of transitioning from firm fixed

  19. Effects of chemopreventive agents on the incidence of recurrent colorectal adenomas: a systematic review with network meta-analysis of randomized controlled trials

    PubMed Central

    Veettil, Sajesh K; Teerawattanapong, Nattawat; Ching, Siew Mooi; Lim, Kean Ghee; Saokaew, Surasak; Phisalprapa, Pochamana; Chaiyakunapruk, Nathorn

    2017-01-01

    Background Protective effects of several chemopreventive agents (CPAs) against colorectal adenomas have been well documented in randomized controlled trials (RCTs); however, there is uncertainty regarding which agents are the most effective. Methods We searched for RCTs published up until September 2016. Retrieved trials were evaluated using risk of bias. We performed both pairwise analysis and network meta-analysis (NMA) of RCTs to compare the effects of CPAs on the recurrence of colorectal adenomas (primary outcome). Using NMA, we ranked CPAs based on efficacy. Results We identified 20 eligible RCTs enrolling 12,625 participants with a history of colorectal cancer or adenomas who were randomly assigned to receive either a placebo or one of 12 interventions. NMA using all trials demonstrated that celecoxib 800 mg/day (relative risk [RR] 0.61, 95% confidence interval [CI] 0.45–0.83), celecoxib 400 mg/day (RR 0.70, 95% CI 0.55–0.87), low-dose aspirin (RR 0.75, 95% CI 0.59–0.96) and calcium (RR 0.81, 95% CI 0.69–0.96) were significantly associated with a reduction in the recurrence of any adenomas. NMA results were consistent with those from pairwise meta-analysis. The evidence indicated a high (celecoxib), moderate (low-dose aspirin) and low (calcium) Grading of Recommendations, Assessment, Development and Evaluation (GRADE) quality. NMA ranking showed that celecoxib 800 mg/day and celecoxib 400 mg/day were the best CPAs, followed by low-dose aspirin and calcium. Considering advanced adenoma recurrence, only celecoxib 800 mg/day and celecoxib 400 mg/day were demonstrated to have a protective effect (RR 0.37, 95% CI 0.27–0.52 vs RR 0.48, 95% CI 0.38–0.60, respectively). Conclusion The available evidence from NMA suggests that celecoxib is more effective in reducing the risk of recurrence of colorectal adenomas, followed by low-dose aspirin and calcium. Since cyclooxygenase-2 (COX-2) inhibitors (eg, celecoxib) are associated with important cardiovascular

  20. Core Knowledge Employee Creativity and Firm Performance: The Moderating Role of Riskiness Orientation, Firm Size, and Realized Absorptive Capacity

    ERIC Educational Resources Information Center

    Gong, Yaping; Zhou, Jing; Chang, Song

    2013-01-01

    In this study, we examine when creativity is positively or negatively related to firm performance. Building on the creation-implementation tension theorized in the literature and the attention capacity perspective, we argue that the relationship between creativity and firm performance is contingent on riskiness orientation, firm size, and realized…

  1. Core Knowledge Employee Creativity and Firm Performance: The Moderating Role of Riskiness Orientation, Firm Size, and Realized Absorptive Capacity

    ERIC Educational Resources Information Center

    Gong, Yaping; Zhou, Jing; Chang, Song

    2013-01-01

    In this study, we examine when creativity is positively or negatively related to firm performance. Building on the creation-implementation tension theorized in the literature and the attention capacity perspective, we argue that the relationship between creativity and firm performance is contingent on riskiness orientation, firm size, and realized…

  2. Collective firm bankruptcies and phase transition in rating dynamics

    NASA Astrophysics Data System (ADS)

    Sieczka, P.; Hołyst, J. A.

    2009-10-01

    We present a simple model of firm rating evolution. We consider two sources of defaults: individual dynamics of economic development and Potts-like interactions between firms. We show that such a defined model leads to phase transition, which results in collective defaults. The existence of the collective phase depends on the mean interaction strength. For small interaction strength parameters, there are many independent bankruptcies of individual companies. For large parameters, there are giant collective defaults of firm clusters. In the case when the individual firm dynamics favors dumping of rating changes, there is an optimal strength of the firm's interactions from the systemic risk point of view. in here

  3. Where Gibrat meets Zipf: Scale and scope of French firms

    NASA Astrophysics Data System (ADS)

    Bee, Marco; Riccaboni, Massimo; Schiavo, Stefano

    2017-09-01

    The proper characterization of the size distribution and growth of firms represents an important issue in economics and business. We use the Maximum Entropy approach to assess the plausibility of the assumption that firm size follows Lognormal or Pareto distributions, which underlies most recent works on the subject. A comprehensive dataset covering the universe of French firms allows us to draw two major conclusions. First, the Pareto hypothesis for the whole distribution should be rejected. Second, by discriminating across firms based on the number of products sold and markets served, we find that, within the class of multi-product companies active in multiple markets, the distribution converges to a Zipf's law. Conversely, Lognormal distribution is a good benchmark for small single-product firms. The size distribution of firms largely depends on firms' diversification patterns.

  4. Changes of firm size distribution: The case of Korea

    NASA Astrophysics Data System (ADS)

    Kang, Sang Hoon; Jiang, Zhuhua; Cheong, Chongcheul; Yoon, Seong-Min

    2011-01-01

    In this paper, the distribution and inequality of firm sizes is evaluated for the Korean firms listed on the stock markets. Using the amount of sales, total assets, capital, and the number of employees, respectively, as a proxy for firm sizes, we find that the upper tail of the Korean firm size distribution can be described by power-law distributions rather than lognormal distributions. Then, we estimate the Zipf parameters of the firm sizes and assess the changes in the magnitude of the exponents. The results show that the calculated Zipf exponents over time increased prior to the financial crisis, but decreased after the crisis. This pattern implies that the degree of inequality in Korean firm sizes had severely deepened prior to the crisis, but lessened after the crisis. Overall, the distribution of Korean firm sizes changes over time, and Zipf’s law is not universal but does hold as a special case.

  5. Effectiveness and reaction networks of H2O2 vapor with NH3 gas for decontamination of the toxic warfare nerve agent, VX on a solid surface.

    PubMed

    Gon Ryu, Sam; Wan Lee, Hae

    2015-01-01

    The nerve agent, O-ethyl S-[2-(diisopropylamino)ethyl] methylphosphonothioate (VX) must be promptly eliminated following its release into the environment because it is extremely toxic, can cause death within a few minutes after exposure, acts through direct skin contact as well as inhalation, and persists in the environment for several weeks after release. A mixture of hydrogen peroxide vapor and ammonia gas was examined as a decontaminant for the removal of VX on solid surfaces at ambient temperature, and the reaction products were analyzed by gas chromatography-mass spectrometry (GC-MS) and nuclear magnetic resonance spectrometry (NMR). All the VX on glass wool filter disks was found to be eliminated after 2 h of exposure to the decontaminant mixtures, and the primary decomposition product was determined to be non-toxic ethyl methylphosphonic acid (EMPA); no toxic S-[2-(diisopropylamino)ethyl] methylphosphonothioic acid (EA-2192), which is usually produced in traditional basic hydrolysis systems, was found to be formed. However, other by-products, such as toxic O-ethyl S-vinyl methylphosphonothioate and (2-diisopropylaminoethyl) vinyl disulfide, were detected up to 150 min of exposure to the decontaminant mixture; these by-products disappeared after 3 h. The two detected vinyl byproducts were identified first in this study with the decontamination system of liquid VX on solid surfaces using a mixture of hydrogen peroxide vapor and ammonia gas. The detailed decontamination reaction networks of VX on solid surfaces produced by the mixture of hydrogen peroxide vapor and ammonia gas were suggested based on the reaction products. These findings suggest that the mixture of hydrogen peroxide vapor and ammonia gas investigated in this study is an efficient decontaminant mixture for the removal of VX on solid surfaces at ambient temperature despite the formation of a toxic by-product in the reaction process.

  6. Folic acid and creatine improve the firmness of human skin in vivo.

    PubMed

    Fischer, Frank; Achterberg, Volker; März, Annette; Puschmann, Stefan; Rahn, Christian-Dennis; Lutz, Vivien; Krüger, Andrea; Schwengler, Helge; Jaspers, Sören; Koop, Urte; Blatt, Thomas; Wenck, Horst; Gallinat, Stefan

    2011-03-01

    The decrease in firmness is a hallmark of skin aging. Accelerated by chronic sun exposure, fundamental changes occur within the dermal extracellular matrix over the years, mainly impairing the collagenous network. Based on the qualitative and quantitative assessment of skin firmness, in vitro and in vivo studies were carried out to elucidate the effects of topical folic acid and creatine to counteract this age-dependent reduction in the amount of collagen. Topical application of a commercially available formulation containing folic acid and creatine was performed to study effects on skin firmness in vivo using cutometric analysis. Imaging and quantification of collagen density were carried out using multiphoton laser scanning microscopy (MPLSM). To investigate the effects of these compounds on collagen gene expression, procollagen synthesis, and collagen fibril organization, complementary in vitro studies on cultured fibroblast-populated collagen gels were carried out. The underlying structural changes in the collagen network of young and aged sun-exposed facial skin in vivo were visualized by MPLSM. Topical application of a folic acid- and creatine-containing formulation significantly improved firmness of mature skin in vivo. Treatment of fibroblast-populated dermal equivalents with folic acid and creatine increased collagen gene expression and procollagen levels and improved collagen fiber density, suggesting that the in vivo effects are based on the overall improvement of the collagen metabolism. Employing MPLSM, dermal changes occurring in photo-aged human skin were visualized in an unprecedented manner and correlated to a loss of firmness. Treatment of aged skin with a topical formulation containing folic acid and creatine counteracted this age-dependent decline by exerting sustained effects on collagen metabolism. Our results support previous findings on the efficacy of these actives. © 2011 Wiley Periodicals, Inc.

  7. Agent Orange

    MedlinePlus

    ... Index Agent Orange Agent Orange Home Facts about Herbicides Veterans' Diseases Birth Defects Benefits Exposure Locations Provider ... Orange Parkinson’s Awareness Month Were you exposed to herbicides during service and have Parkinson’s disease? You may ...

  8. Exporting licensing regulations affecting US geothermal firms

    SciTech Connect

    Not Available

    1988-08-01

    This document presents a brief introduction and overview of the Department of Commerce's Export Administration Regulations which might affect potential US geothermal goods exporters. It is intended to make US geothermal firms officials aware of the existence of such regulations and to provide them with references, contacts and phone numbers where they can obtain specific and detailed information and assistance. It must be stressed however, that the ultimate responsibility for complying with the above mentioned regulations lies with the exporter who must consult the complete version of the regulations.

  9. Family as Economic Socialization Agent.

    ERIC Educational Resources Information Center

    Rettig, Kathryn Dalbey

    1983-01-01

    The family operates as an economic socialization agent through the provision of (1) economic information networks, (2) grants and exchanges of resources, (3) economic role models, and (4) an environment for the development of individual human resource attributes. (SK)

  10. Maintaining Limited-Range Connectivity Among Second-Order Agents

    DTIC Science & Technology

    2016-07-07

    we consider ad-hoc networks of robotic agents with double integrator dynamics. For such networks, the connectivity maintenance problems are: (i) do...hoc networks of mobile autonomous agents. This loose ter- minology refers to groups of robotic agents with limited mobility and communica- tion...connectivity can be preserved. 3.1. Networks of robotic agents with second-order dynamics and the connectivity maintenance problem. We begin by

  11. A network of networks.

    PubMed

    Iedema, Rick; Verma, Raj; Wutzke, Sonia; Lyons, Nigel; McCaughan, Brian

    2017-04-10

    Purpose To further our insight into the role of networks in health system reform, the purpose of this paper is to investigate how one agency, the NSW Agency for Clinical Innovation (ACI), and the multiple networks and enabling resources that it encompasses, govern, manage and extend the potential of networks for healthcare practice improvement. Design/methodology/approach This is a case study investigation which took place over ten months through the first author's participation in network activities and discussions with the agency's staff about their main objectives, challenges and achievements, and with selected services around the state of New South Wales to understand the agency's implementation and large system transformation activities. Findings The paper demonstrates that ACI accommodates multiple networks whose oversight structures, self-organisation and systems change approaches combined in dynamic ways, effectively yield a diversity of network governances. Further, ACI bears out a paradox of "centralised decentralisation", co-locating agents of innovation with networks of implementation and evaluation expertise. This arrangement strengthens and legitimates the role of the strategic hybrid - the healthcare professional in pursuit of change and improvement, and enhances their influence and impact on the wider system. Research limitations/implications While focussing the case study on one agency only, this study is unique as it highlights inter-network connections. Contributing to the literature on network governance, this paper identifies ACI as a "network of networks" through which resources, expectations and stakeholder dynamics are dynamically and flexibly mediated and enhanced. Practical implications The co-location of and dynamic interaction among clinical networks may create synergies among networks, nurture "strategic hybrids", and enhance the impact of network activities on health system reform. Social implications Network governance requires more

  12. Strategic Orientation in the Globalization of Software Firms

    NASA Astrophysics Data System (ADS)

    Dedrick, Jason; Kraemer, Kenneth L.; Carmel, Erran; Dunkle, Debora

    In the search for profits, software firms are globalizing their development activities. Some firms achieve greater profits by becoming more efficient, whereas others do so by reaching new markets; some do both. This paper creates an a priori typology of strategies based on the extent to which firms are focused on operational improvement or market access, have a dual focus or are unfocused. We find that firms with these strategies differ in degree of internationalization, organization of offshoring and performance outcomes related to offshoring. Market-oriented firms receive a greater proportion of their total revenue from sales outside the U.S., showing a greater international orientation. They keep more of their offshore development in-house via captive operations. They also are most likely to report increased non-U.S. sales as a result of offshoring. On the other hand, operations-oriented firms have lower levels of international sales, are more likely to go offshore via outsourced software development, and achieve greater costs savings and labor force flexibility as a result of offshoring. Operations-oriented firms also face more obstacles in offshoring, perhaps because of their reliance on outsourcing. Dual focus firms generally achieve some of the best of both strategies, whereas unfocused firms achieve lower cost benefits.

  13. Financial Constrains for Innovative Firms: The Role of Size, Industry and ICT Uses as Determinants of Firms' Financial Structure

    NASA Astrophysics Data System (ADS)

    Castillo-Merino, David; Vilaseca-Requena, Jordi; Plana-Erta, Dolors

    This paper uses a large and original data set of Catalan firms in all the economic branches to analyse the effects of size, industry and degree of ICT uses on financial constraints for innovative firms. We have conducted a micro econometric analysis following Henry et al. (1999) investment model to empirically contrast the relationship between firms' investment spread over time and their financial structure, and we have used von Kalckreuth (2004) methodology, based on an original survey with data on financial issues. Our results show that it exits a positive and significant relationship between investment shift and financial structure, emerging financial constraints for more innovative firms. Furthermore, these constraints are higher for micro companies and firms within the knowledge-advanced services' industry. Finally, we have also found that advanced ICT uses by more innovative firms allow them to reduce constraints of access to sources of finance.

  14. 49 CFR 551.58 - Who may sign the Acceptance by Agent?

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 6 2010-10-01 2010-10-01 false Who may sign the Acceptance by Agent? 551.58... Manufacturers and Importers Form and Contents of Designation § 551.58 Who may sign the Acceptance by Agent? Only... corporation serving as the agent with authority to sign for that firm of corporation, may sign the Acceptance...

  15. 49 CFR 551.58 - Who may sign the Acceptance by Agent?

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 6 2014-10-01 2014-10-01 false Who may sign the Acceptance by Agent? 551.58... Manufacturers and Importers Form and Contents of Designation § 551.58 Who may sign the Acceptance by Agent? Only... corporation serving as the agent with authority to sign for that firm of corporation, may sign the Acceptance...

  16. Does it pay to have a network contact? Social network ties, workplace racial context, and pay outcomes.

    PubMed

    Kmec, Julie A; Trimble, Lindsey B

    2009-06-01

    This article investigates how social network use to find work affects pay. Analyses using the Multi-City Study of Urban Inequality consider the extent to which a network contact's influence level affects a job applicant's pay, whether this effect differs for white, black, and Latino contacts, and how workplace racial context moderates this relationship. Three main findings emerge. First, having an influential contact--one with hiring authority--compared to having no contact yields higher pay. Second, white and minority contact influence on pay differs: among minority contacts, being an outsider (i.e., someone not employed by the firm to which the applicant applies) is associated with higher pay, but being an employee of the firm--an insider--is not. Third, regardless of workplace racial context, black and Latino contacts' influence is most beneficial when their race/ethnicity is not known to the hiring agent. We offer a new interpretation of the mixed findings with regard to the relationship between social network use and pay.

  17. Agent-based forward analysis

    SciTech Connect

    Kerekes, Ryan A.; Jiao, Yu; Shankar, Mallikarjun; Potok, Thomas E.; Lusk, Rick M.

    2008-01-01

    We propose software agent-based "forward analysis" for efficient information retrieval in a network of sensing devices. In our approach, processing is pushed to the data at the edge of the network via intelligent software agents rather than pulling data to a central facility for processing. The agents are deployed with a specific query and perform varying levels of analysis of the data, communicating with each other and sending only relevant information back across the network. We demonstrate our concept in the context of face recognition using a wireless test bed comprised of PDA cell phones and laptops. We show that agent-based forward analysis can provide a significant increase in retrieval speed while decreasing bandwidth usage and information overload at the central facility. n

  18. Learning in innovation networks: Some simulation experiments

    NASA Astrophysics Data System (ADS)

    Gilbert, Nigel; Ahrweiler, Petra; Pyka, Andreas

    2007-05-01

    According to the organizational learning literature, the greatest competitive advantage a firm has is its ability to learn. In this paper, a framework for modeling learning competence in firms is presented to improve the understanding of managing innovation. Firms with different knowledge stocks attempt to improve their economic performance by engaging in radical or incremental innovation activities and through partnerships and networking with other firms. In trying to vary and/or to stabilize their knowledge stocks by organizational learning, they attempt to adapt to environmental requirements while the market strongly selects on the results. The simulation experiments show the impact of different learning activities, underlining the importance of innovation and learning.

  19. Efficacy and Safety Profile of Anti-tumor Necrosis Factor-α Versus Anti-integrin Agents for the Treatment of Crohn's Disease: A Network Meta-analysis of Indirect Comparisons.

    PubMed

    Miligkos, Michael; Papamichael, Konstantinos; Vande Casteele, Niels; Mantzaris, Gerassimos J; Gils, Ann; Levesque, Barrett G; Zintzaras, Elias

    2016-06-01

    To compare the benefits and harms of anti-tumor necrosis factor (TNF)-α and anti-integrin agents as induction and maintenance therapy in adult patients with Crohn's disease. We searched MEDLINE and the Cochrane Central Register of Controlled Trials from inception through July 2015 for randomized clinical trials in patients with Crohn's disease who reported response or remission with anti-TNF-α or anti-integrin agents administered as induction and/or maintenance therapy. Data on the study population, interventions, outcome measures, adverse events, and study methods were extracted independently by 2 authors. Among 2503 citations identified, 23 met the eligibility criteria. Random-effects model meta-analyses and network meta-analyses were performed. No statistically significant difference was observed between anti-TNF-α and anti-integrin agents with respect to induction and maintenance of response (odds ratio [OR] = 1.20 [95% CI, 0.73-1.96] from 14 trials and OR = 1.23 [95% CI, 0.50-3.03] from 8 trials, respectively) or remission (OR = 1.13 [95% CI, 0.72-1.76] from 17 trials and OR = 1.18 [95% CI, 0.55-2.50] from 9 trials, respectively). No difference was observed in the indirect comparison of trials that reported results on the subgroup of anti-TNF-α naive patients. The proportions of patients with adverse events, infections, and treatment discontinuations were similar between the agents. Our indirect treatment comparisons did not find a statistically significant difference between anti-TNF-α and anti-integrin agents for induction or maintenance therapy. In the absence of head-to-head comparisons, it remains unclear which patient is more likely to respond better to any of these agents. Copyright © 2016 Elsevier HS Journals, Inc. All rights reserved.

  20. Architecture of firm dynamic capabilities across inter-organizational activities: Explaining innovativeness in the context of nanotechnology

    NASA Astrophysics Data System (ADS)

    Petricevic, Olga

    In this dissertation I first develop a theoretical framework that explores different components of dynamic capabilities related to firm's boundary-spanning linkages across two different types of inter-organizational activities---alliances and networks. I argue that there are four different subsets of dynamic capabilities simultaneously at work: alliance opportunity-sensing, alliance opportunity-seizing, network opportunity-sensing and network opportunity-seizing. Furthermore, I argue that there are significant interaction effects between these distinctive subsets driving the firm's overall effectiveness in sensing and seizing of novel and innovative external opportunities. In order to explore potential interdependencies and draw distinctions among different dynamic capability subsets I integrate concepts from the two theoretical perspectives that often neglect the emphasis of the other---the dynamic capability view and the social network perspective. I then test the hypothesized relationships in the context of firms actively patenting in nanotechnology. Nanotechnology innovations are multidisciplinary in nature and require search and discovery across multiple inter-organizational, scientific, geographic, industry, or technological domains by a particular firm. The findings offer support for the conceptualizations of dynamic capabilities as consisting of distinct subsets of capabilities for the sensing and the seizing of external new-knowledge opportunities. The findings suggest that firm's innovativeness in an interdisciplinary scientific field such as nanotechnology is the function of the vector of multi-dimensional dynamic capabilities that are context-specific. Furthermore, the findings also suggest that there are inherent trade-offs embedded in different dimensions of dynamic capabilities when deployed across a wide range of inter-organizational relationships.

  1. The Need for Writing Skill in Accounting Firms.

    ERIC Educational Resources Information Center

    Northey, Margot

    1990-01-01

    Assesses the need for good writing skills in large accounting firms that operate in an increasingly competitive environment with new imperatives of client service and business development. Analyzes specific kinds of writing by professional accountants, and examines how firms encourage good writing through training, hiring, and evaluation…

  2. ICT, complementary investment, and firm performance in China

    NASA Astrophysics Data System (ADS)

    Sun, Linlin; Ding, Juan; Fan, Maoqing

    2011-12-01

    Using China firm data about ICT, we provide some insight into the link between ICT, productivity and complementary investment. The results show that the contribution of ICT capital deepening is raised when firms combine ICT use and some complementary investment (human capital, innovation and organization change).

  3. How Knowledge Organisations Work: The Case of Software Firms

    ERIC Educational Resources Information Center

    Gottschalk, Petter

    2007-01-01

    Knowledge workers in software firms solve client problems in sequential and cyclical work processes. Sequential and cyclical work takes place in the value configuration of a value shop. While typical examples of value chains are manufacturing industries such as paper and car production, typical examples of value shops are law firms and medical…

  4. 37 CFR 10.35 - Firm names and letterheads.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 37 Patents, Trademarks, and Copyrights 1 2012-07-01 2012-07-01 false Firm names and letterheads. 10.35 Section 10.35 Patents, Trademarks, and Copyrights UNITED STATES PATENT AND TRADEMARK OFFICE... Office Code of Professional Responsibility § 10.35 Firm names and letterheads. (a) A practitioner shall...

  5. Firm Size, Ownership, Training Duration and Training Evaluation Practices

    ERIC Educational Resources Information Center

    Asadullah, Muhammad Ali; Peretti, Jean Marie; Ali, Arain Ghulam; Bourgain, Marina

    2015-01-01

    Purpose: The purpose of this paper was to test the mediating role of training duration in relationship between firm characteristics and training evaluation practices. In this paper, the authors also investigated if this mediating effect differs with respect to the size of the firm. Design/methodology/approach: The authors collected data from 260…

  6. A "Firm" System for Graduate Training in General Internal Medicine.

    ERIC Educational Resources Information Center

    And Others; Waggoner, David M.

    1979-01-01

    The Department of Medicine at Cleveland Metropolitan General Hospital fosters general internal medicine in a graduate training program with a "medical firm" system of medical care. The firm system consists of four medical teams that care for distinct patient populations, closely integrating outpatient and inpatient care. (Author/JMD)

  7. Training's Practices: Education and Training within the American Firm.

    ERIC Educational Resources Information Center

    Zemsky, Robert; Meyerson, Martin

    A study examined the training provided to workers by 20 firms across the Nation. In the 12 years between 1969 and 1981, American firms increased their expenditures on employee training from $2.4 to $3.5 million according to an analysis of data gathered by Current Population Surveys. In the same period, members of the American Society for Training…

  8. Firm Size, Ownership, Training Duration and Training Evaluation Practices

    ERIC Educational Resources Information Center

    Asadullah, Muhammad Ali; Peretti, Jean Marie; Ali, Arain Ghulam; Bourgain, Marina

    2015-01-01

    Purpose: The purpose of this paper was to test the mediating role of training duration in relationship between firm characteristics and training evaluation practices. In this paper, the authors also investigated if this mediating effect differs with respect to the size of the firm. Design/methodology/approach: The authors collected data from 260…

  9. Determinants of Successful Training Practices in Large Australian Firms.

    ERIC Educational Resources Information Center

    Dawe, Susan

    The determinants of successful training practices in large Australian firms were examined. The study's three phases were as follows: (1) a review of existing literature; (2) a meta-analysis of previously conducted case studies of 49 large Australian firms in 14 industrial sectors; and (3) a comparative analysis of the findings of the past studies…

  10. Determinants of Successful Training Practices in Large Australian Firms.

    ERIC Educational Resources Information Center

    Dawe, Susan

    The determinants of successful training practices in large Australian firms were examined. The study's three phases were as follows: (1) a review of existing literature; (2) a meta-analysis of previously conducted case studies of 49 large Australian firms in 14 industrial sectors; and (3) a comparative analysis of the findings of the past studies…

  11. 39 CFR 281.1 - Notification of firm mailers.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... customer services at the office of mailing to give known mailers timely notification of the incident and... 39 Postal Service 1 2010-07-01 2010-07-01 false Notification of firm mailers. 281.1 Section 281.1 Postal Service UNITED STATES POSTAL SERVICE ORGANIZATION AND ADMINISTRATION FIRM MAILINGS DAMAGED OR...

  12. 39 CFR 281.1 - Notification of firm mailers.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... customer services at the office of mailing to give known mailers timely notification of the incident and... 39 Postal Service 1 2011-07-01 2011-07-01 false Notification of firm mailers. 281.1 Section 281.1 Postal Service UNITED STATES POSTAL SERVICE ORGANIZATION AND ADMINISTRATION FIRM MAILINGS DAMAGED OR...

  13. 48 CFR 1816.202 - Firm-fixed-price contracts.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 6 2010-10-01 2010-10-01 true Firm-fixed-price contracts... ADMINISTRATION CONTRACTING METHODS AND CONTRACT TYPES TYPES OF CONTRACTS Fixed-Price Contracts 1816.202 Firm-fixed-price contracts. ...

  14. 48 CFR 16.202 - Firm-fixed-price contracts.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 1 2014-10-01 2014-10-01 false Firm-fixed-price contracts. 16.202 Section 16.202 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION CONTRACTING METHODS AND CONTRACT TYPES TYPES OF CONTRACTS Fixed-Price Contracts 16.202 Firm-fixed-price...

  15. 48 CFR 16.202 - Firm-fixed-price contracts.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 1 2011-10-01 2011-10-01 false Firm-fixed-price contracts. 16.202 Section 16.202 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION CONTRACTING METHODS AND CONTRACT TYPES TYPES OF CONTRACTS Fixed-Price Contracts 16.202 Firm-fixed-price...

  16. 48 CFR 16.202 - Firm-fixed-price contracts.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false Firm-fixed-price contracts. 16.202 Section 16.202 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION CONTRACTING METHODS AND CONTRACT TYPES TYPES OF CONTRACTS Fixed-Price Contracts 16.202 Firm-fixed-price...

  17. 48 CFR 16.202 - Firm-fixed-price contracts.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 1 2013-10-01 2013-10-01 false Firm-fixed-price contracts. 16.202 Section 16.202 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION CONTRACTING METHODS AND CONTRACT TYPES TYPES OF CONTRACTS Fixed-Price Contracts 16.202 Firm-fixed-price...

  18. 48 CFR 1816.202 - Firm-fixed-price contracts.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 6 2012-10-01 2012-10-01 false Firm-fixed-price contracts... ADMINISTRATION CONTRACTING METHODS AND CONTRACT TYPES TYPES OF CONTRACTS Fixed-Price Contracts 1816.202 Firm-fixed-price contracts. ...

  19. 48 CFR 1816.202 - Firm-fixed-price contracts.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 6 2013-10-01 2013-10-01 false Firm-fixed-price contracts... ADMINISTRATION CONTRACTING METHODS AND CONTRACT TYPES TYPES OF CONTRACTS Fixed-Price Contracts 1816.202 Firm-fixed-price contracts. ...

  20. 48 CFR 1816.202 - Firm-fixed-price contracts.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 6 2011-10-01 2011-10-01 false Firm-fixed-price contracts... ADMINISTRATION CONTRACTING METHODS AND CONTRACT TYPES TYPES OF CONTRACTS Fixed-Price Contracts 1816.202 Firm-fixed-price contracts. ...

  1. 48 CFR 1816.202 - Firm-fixed-price contracts.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 6 2014-10-01 2014-10-01 false Firm-fixed-price contracts... ADMINISTRATION CONTRACTING METHODS AND CONTRACT TYPES TYPES OF CONTRACTS Fixed-Price Contracts 1816.202 Firm-fixed-price contracts. ...

  2. 48 CFR 16.202 - Firm-fixed-price contracts.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 1 2012-10-01 2012-10-01 false Firm-fixed-price contracts. 16.202 Section 16.202 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION CONTRACTING METHODS AND CONTRACT TYPES TYPES OF CONTRACTS Fixed-Price Contracts 16.202 Firm-fixed-price...

  3. Is Transfer of Training Related to Firm Performance?

    ERIC Educational Resources Information Center

    Saks, Alan M.; Burke-Smalley, Lisa A.

    2014-01-01

    The purpose of this study was to bridge the gap between micro-training research on the transfer of training and macro-training research on training and firm performance by testing the relationship between transfer of training and firm performance. Training and development professionals completed a survey about the training methods used in their…

  4. Is Transfer of Training Related to Firm Performance?

    ERIC Educational Resources Information Center

    Saks, Alan M.; Burke-Smalley, Lisa A.

    2014-01-01

    The purpose of this study was to bridge the gap between micro-training research on the transfer of training and macro-training research on training and firm performance by testing the relationship between transfer of training and firm performance. Training and development professionals completed a survey about the training methods used in their…

  5. 39 CFR 281.1 - Notification of firm mailers.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... customer services at the office of mailing to give known mailers timely notification of the incident and... 39 Postal Service 1 2014-07-01 2014-07-01 false Notification of firm mailers. 281.1 Section 281.1 Postal Service UNITED STATES POSTAL SERVICE ORGANIZATION AND ADMINISTRATION FIRM MAILINGS DAMAGED...

  6. 39 CFR 281.1 - Notification of firm mailers.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... customer services at the office of mailing to give known mailers timely notification of the incident and... 39 Postal Service 1 2012-07-01 2012-07-01 false Notification of firm mailers. 281.1 Section 281.1 Postal Service UNITED STATES POSTAL SERVICE ORGANIZATION AND ADMINISTRATION FIRM MAILINGS DAMAGED...

  7. 39 CFR 281.1 - Notification of firm mailers.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... customer services at the office of mailing to give known mailers timely notification of the incident and... 39 Postal Service 1 2013-07-01 2013-07-01 false Notification of firm mailers. 281.1 Section 281.1 Postal Service UNITED STATES POSTAL SERVICE ORGANIZATION AND ADMINISTRATION FIRM MAILINGS DAMAGED...

  8. Hospitals look to hospitality service firms to meet TQM goals.

    PubMed

    Hard, R

    1992-05-20

    Hospitals that hire contract service firms to manage one or all aspects of their hospitality service departments increasingly expect those firms to help meet total quality management goals as well as offer the more traditional cost reduction, quality improvement and specialized expertise, finds the 1992 Hospital Contract Services Survey conducted by Hospitals.

  9. How to Examine Legal Bills: Assessing Law Firms' Invoices.

    ERIC Educational Resources Information Center

    Feigenbaum, Bennett

    1994-01-01

    Because law firms' legal bills frequently are complex, clients often have a difficult time examining them. Management accountants should read the retention letter between the law firm and the school district and assess the reasonableness of professional fees. Costs that require particular attention include travel time, photocopying, secretarial…

  10. How Knowledge Organisations Work: The Case of Software Firms

    ERIC Educational Resources Information Center

    Gottschalk, Petter

    2007-01-01

    Knowledge workers in software firms solve client problems in sequential and cyclical work processes. Sequential and cyclical work takes place in the value configuration of a value shop. While typical examples of value chains are manufacturing industries such as paper and car production, typical examples of value shops are law firms and medical…

  11. 49 CFR 1522.103 - Requirements for validation firms.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ..., resources, and personnel to conduct the assessments. (b) Security Coordinator. The validation firm must... obtain TSA approval of a security program and must implement the security program. (d) Personnel. The validation firm must ensure that its personnel carry out the requirements of this chapter and the validation...

  12. Swimming microorganisms acting as nanorobots versus artificial nanorobotic agents: A perspective view from an historical retrospective on the future of medical nanorobotics in the largest known three-dimensional biomicrofluidic networks

    PubMed Central

    Martel, Sylvain

    2016-01-01

    The vascular system in each human can be described as a 3D biomicrofluidic network providing a pathway close to approximately 100 000 km in length. Such network can be exploited to target any parts inside the human body with further accessibility through physiological spaces such as the interstitial microenvironments. This fact has triggered research initiatives towards the development of new medical tools in the form of microscopic robotic agents designed for surgical, therapeutic, imaging, or diagnostic applications. To push the technology further towards medical applications, nanotechnology including nanomedicine has been integrated with principles of robotics. This new field of research is known as medical nanorobotics. It has been particularly creative in recent years to make what was and often still considered science-fiction to offer concrete implementations with the potential to enhance significantly many actual medical practices. In such a global effort, two main strategic trends have emerged where artificial and synthetic implementations presently compete with swimming microorganisms being harnessed to act as medical nanorobotic agents. Recognizing the potentials of each approach, efforts to combine both towards the implementation of hybrid nanorobotic agents where functionalities are implemented using both artificial/synthetic and microorganism-based entities have also been initiated. Here, through the main eras of progressive developments in this field, the evolutionary path being described from some of the main historical achievements to recent technological innovations is extrapolated in an attempt to provide a perspective view on the future of medical nanorobotics capable of targeting any parts of the human body accessible through the vascular network. PMID:27158285

  13. Swimming microorganisms acting as nanorobots versus artificial nanorobotic agents: A perspective view from an historical retrospective on the future of medical nanorobotics in the largest known three-dimensional biomicrofluidic networks.

    PubMed

    Martel, Sylvain

    2016-03-01

    The vascular system in each human can be described as a 3D biomicrofluidic network providing a pathway close to approximately 100 000 km in length. Such network can be exploited to target any parts inside the human body with further accessibility through physiological spaces such as the interstitial microenvironments. This fact has triggered research initiatives towards the development of new medical tools in the form of microscopic robotic agents designed for surgical, therapeutic, imaging, or diagnostic applications. To push the technology further towards medical applications, nanotechnology including nanomedicine has been integrated with principles of robotics. This new field of research is known as medical nanorobotics. It has been particularly creative in recent years to make what was and often still considered science-fiction to offer concrete implementations with the potential to enhance significantly many actual medical practices. In such a global effort, two main strategic trends have emerged where artificial and synthetic implementations presently compete with swimming microorganisms being harnessed to act as medical nanorobotic agents. Recognizing the potentials of each approach, efforts to combine both towards the implementation of hybrid nanorobotic agents where functionalities are implemented using both artificial/synthetic and microorganism-based entities have also been initiated. Here, through the main eras of progressive developments in this field, the evolutionary path being described from some of the main historical achievements to recent technological innovations is extrapolated in an attempt to provide a perspective view on the future of medical nanorobotics capable of targeting any parts of the human body accessible through the vascular network.

  14. Knowledge spillover processes as complex networks

    NASA Astrophysics Data System (ADS)

    Konno, Tomohiko

    2016-11-01

    We introduce the model of knowledge spillover on networks. Knowledge spillover is a major source of economic growth; and is a representative externality in economic phenomena. We show that the model has the following four characteristics: (1) the long-run growth rate is not relevant to the mean degree, but is determined by the mean degree of the nearest neighbors; (2) the productivity level of a firm is proportional to the degree of the firm; (3) the long-run growth rate increases with the increasing heterogeneity of the network; and (4) of three representative networks, the largest growth rate is in scale-free networks and the least in regular networks.

  15. Environmental performance indicators: an empirical study of Canadian manufacturing firms.

    PubMed

    Henri, Jean-François; Journeault, Marc

    2008-04-01

    The aim of this exploratory study is to examine the importance of measurement and use of environmental performance indicators (EPIs) within manufacturing firms. Two research questions are investigated: (i) To what extent are firm characteristics associated with the importance of measurement of various categories of EPIs? (ii) To what extent are firm characteristics associated with global and specific uses of EPIs? More specifically, this paper examines four uses of EPIs (i.e. to monitor compliance, to motivate continuous improvement, to support decision making, and to provide data for external reporting) as well as four characteristics of firms, namely environmental strategy, International Organization for Standardization (ISO) 14001 compliance, size, and ownership. This study contributes to the environmental management accounting literature by collecting and analyzing empirical evidence that provides a better understanding of the associations among firm characteristics and EPIs.

  16. Evaluation of udder firmness by palpation and a dynamometer.

    PubMed

    Rees, A; Fischer-Tenhagen, C; Heuwieser, W

    2014-01-01

    Swelling of the mammary gland is an important health status sign for clinical exploration and palpation is a routine diagnostic tool for mastitis detection in dairy cows. Data on repeatability or validity of specific methods of udder palpation are rare. The overall objective was to study the validity of estimates of udder firmness generated by palpation and by using a validated dynamometer. Specifically, we set out to determine within-observer repeatability and between-observer repeatability in 2 specific experiments. Additionally, we compared a 4-point palpation scoring system with estimates obtained with a dynamometer in this study. In a pilot trial, we determined the range of udder firmness of 25 cows and developed an in vitro model for udder firmness. This model enabled training of the observers and allowed investigating a 4-point palpation scoring system. In vivo, udder firmness was determined before and after milking by palpation and by using a dynamometer. Within-observer repeatability based on estimates of udder firmness of 25 cows obtained by 3 observers on a single day by palpation was 0.968. Within-observer repeatability of estimates of udder firmness of 25 cows obtained with the dynamometer by a single observer was 0.997. The coefficient of variation of the same measures was 9.1%. To determine between-observer repeatability (palpation: 0.932; dynamometer: 0.898), udder firmness of 100 cows was measured on 4 different days by 9 observers in experiment 2. Udder firmness in dairy cows could be measured repeatably with the dynamometer and by palpation, especially when performed by a single observer. Estimates of udder firmness generated by palpation and with the dynamometer were moderately related (correlation coefficient = 0.54). Training of observers through the pilot trial or practical experience in the 4 d of the study in experiment 2 did not improve the correlation. Further research is warranted to understand how udder firmness develops in infected

  17. When the firm prevents the crash: Avoiding market collapse with partial control.

    PubMed

    Levi, Asaf; Sabuco, Juan; A F Sanjuán, Miguel

    2017-01-01

    Market collapse is one of the most dramatic events in economics. Such a catastrophic event can emerge from the nonlinear interactions between the economic agents at the micro level of the economy. Transient chaos might be a good description of how a collapsing market behaves. In this work, we apply a new control method, the partial control method, with the goal of avoiding this disastrous event. Contrary to common control methods that try to influence the system from the outside, here the market is controlled from the bottom up by one of the most basic components of the market-the firm. This is the first time that the partial control method is applied on a strictly economical system in which we also introduce external disturbances. We show how the firm is capable of controlling the system avoiding the collapse by only adjusting the selling price of the product or the quantity of production in accordance to the market circumstances. Additionally, we demonstrate how a firm with a large market share is capable of influencing the demand achieving price stability across the retail and wholesale markets. Furthermore, we prove that the control applied in both cases is much smaller than the external disturbances.

  18. When the firm prevents the crash: Avoiding market collapse with partial control

    PubMed Central

    2017-01-01

    Market collapse is one of the most dramatic events in economics. Such a catastrophic event can emerge from the nonlinear interactions between the economic agents at the micro level of the economy. Transient chaos might be a good description of how a collapsing market behaves. In this work, we apply a new control method, the partial control method, with the goal of avoiding this disastrous event. Contrary to common control methods that try to influence the system from the outside, here the market is controlled from the bottom up by one of the most basic components of the market—the firm. This is the first time that the partial control method is applied on a strictly economical system in which we also introduce external disturbances. We show how the firm is capable of controlling the system avoiding the collapse by only adjusting the selling price of the product or the quantity of production in accordance to the market circumstances. Additionally, we demonstrate how a firm with a large market share is capable of influencing the demand achieving price stability across the retail and wholesale markets. Furthermore, we prove that the control applied in both cases is much smaller than the external disturbances. PMID:28832608

  19. Educational Competencies That Mid-Sized CPA Firms Value in Their Professional Accounting Staff

    ERIC Educational Resources Information Center

    Margheim, Loren; Hora, Judith A.; Pattison, Diane

    2010-01-01

    This study examined the educational competencies mid-sized accounting firm partners value in their professional staff when making promotion decisions to senior, manager, and partner. Mid-sized firms were defined in this study to include all of the non-Big 4 national firms, the large regional CPA firms, and several large local firms. Over 1,380…

  20. 75 FR 66796 - Pricewaterhousecoopers LLP (“PwC”), Internal Firm Services Client Account Administrators Group...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-29

    ... Assistance on May 20, 2010, applicable to workers of PricewaterhouseCoopers LLP, Division of Internal Firm... subject firm should read PricewaterhouseCoopers LLP (``PwC''), Internal Firm Services Client Account... subject firm to read PricewaterhouseCoopers LLP (``PwC''), Internal Firm Services Client Account...

  1. Biological Agents

    MedlinePlus

    ... is required. Biological Agents Menu Overview In Focus: Ebola Frederick A. Murphy/CDC OSHA's Ebola webpage provides ... OSHA offers, visit OSHA's Workers' page. In Focus: Ebola Frederick A. Murphy/CDC OSHA's Ebola webpage provides ...

  2. IPPF firm reconciles money with mission.

    PubMed

    1991-01-01

    Despite its seemingly conflicting goals, the Family Health Management Service (FHMS) has become an important middleman agency for contraceptives. A for-profit subsidiary of the International Planned Parenthood Federation (IPPF), FHMS has established itself by helping fill the funding gap left by large international donor agencies. FHMS acts as consulting and procurement firm of contraceptives for smaller family planning programs around the world. These organizations, whether government or private, are generally too small to qualify extensive assistance from major donor groups. Although FHMS is a for-profit organization, its leadership stresses that its main goal is to make family planning knowledge and skills available to everyone. FHMS makes a determination whether the organization seeking contraceptives is a charitable or commercial enterprise. If the organization is charitable, FHMS charges only a handling fee. If the organization is commercial, FHMS adds a percentage to make the cost of the contraceptive reflect the market value. Since it begun operating in 1988, FHMS has assisted hundreds of customers. When Action Aid needed 6000 contraceptive products (a figure too small to attract funding from large donor organizations but too large to buy in the open market) for its rural development program in sierra Leone, FHMS procured them at an affordable cost. Last year, the organization spent about $1 million in procuring, shipping, and managing contraceptive sales, and netted a profit of about $45,000. All profits are channeled back to IPPF's altruistic programs.

  3. Chemical, power firms team up in cogeneration

    SciTech Connect

    Ainsworth, S.

    1994-02-21

    US chemical producers are more eager than ever to free up any available capital by shedding operation that are not central to their businesses. As part of this soul searching, chemical companies are questioning whether they should continue to invest the time and tie up capital necessary to operate on-site power generation facilities. Many chemical firms have long produced their own power through the process of cogeneration--which allows for the simultaneous production of electricity and steam from the same energy source--because it provides reliable power at low cost. But in this back-to-basics environment, petrochemical producers want the benefits of self-generation without the headaches. Recognizing this, electric utilities are spinning off independent power subsidiaries. These companies can venture out of the utility's traditional service area to aggressively seek to own or operate cogeneration facilities and then supply other companies with an economical source of power. Providing such services is an attractive way for power companies to diversify their business and buoy return on investment enough to satisfy restless shareholders. Companies in the chemical and related industries pose a prime opportunity because their plants have relatively large requirements for both electricity and steam. As these two trends converge, industry consultants predict an increasing number of chemical and power companies will form mutually beneficial partnerships.

  4. Deciding on Open Innovation: An Exploration of How Firms Create and Capture Value with Open Source Software

    NASA Astrophysics Data System (ADS)

    Morgan, Lorraine; Finnegan, Patrick

    Open innovation is a paradigm that proposes that firms can and should use external as well as internal innovations/ideas. A popular example of open innovation has been open source software (OSS). The key issues facing organizational decision makers considering OSS strategies is, how does the firm create value for the customer while simultaneously extracting value for itself? However, the adoption of OSS as part of an open innovation strategy is a recent phenomenon and many unanswered questions remain. Taking the viewpoint of seven IS/IT decision makers in European firms, this paper reveals how decision makers considered aspects of value creation, capture, and networking in making decisions on adopting open source software. The findings reveal that while decision makers look to open innovation for value creation and capture, there is still a desire to remain self reliant, resulting in collaborative design (of external innovations) rather than collaborative decision making with value network partners in relation to how such innovations would help create and capture value within firms.

  5. Optoelectronics-related competence building in Japanese and Western firms

    NASA Astrophysics Data System (ADS)

    Miyazaki, Kumiko

    1992-05-01

    In this paper, an analysis is made of how different firms in Japan and the West have developed competence related to optoelectronics on the basis of their previous experience and corporate strategies. The sample consists of a set of seven Japanese and four Western firms in the industrial, consumer electronics and materials sectors. Optoelectronics is divided into subfields including optical communications systems, optical fibers, optoelectronic key components, liquid crystal displays, optical disks, and others. The relative strengths and weaknesses of companies in the various subfields are determined using the INSPEC database, from 1976 to 1989. Parallel data are analyzed using OTAF U.S. patent statistics and the two sets of data are compared. The statistical analysis from the database is summarized for firms in each subfield in the form of an intra-firm technology index (IFTI), a new technique introduced to assess the revealed technology advantage of firms. The quantitative evaluation is complemented by results from intensive interviews with the management and scientists of the firms involved. The findings show that there is a marked variation in the way firms' technological trajectories have evolved giving rise to strength in some and weakness in other subfields for the different companies, which are related to their accumulated core competencies, previous core business activities, organizational, marketing, and competitive factors.

  6. Global Greening Is Firm, Drivers Are Mixed

    NASA Astrophysics Data System (ADS)

    Kauppi, P.; Meyfroidt, P.; Ausubel, J. H.; Graven, H. D.; Birdsey, R.; Posch, M.; Wernick, I.; Myneni, R. B.; Stenberg, P.

    2015-12-01

    Evidence for global greening is converging, asserting an increase in CO2 uptake and biomass of the terrestrial biosphere. Global greening refers to global net increases in the area of green canopy, stocks of carbon, and the duration of the growing season. The growing seasons in general have prolonged while the stock of biomass carbon has increased and the rate of deforestation has decelerated, although these trends are mixed in the Tropics. Evidence for these trends comes from firm empirical data obtained through atmospheric CO2 observations, remote sensing, forest inventories and land use statistics. The drivers of global greening cannot be assessed based only on unambiguous empirical measurements. They include spatially and temporally heterogeneous combinations of changing land use and management - including green revolution and increasing yields, afforestation, forest protection and management, and abandonment of agricultural land -, changes in the global environment (increased CO2, warmer temperatures and longer growing seasons in the northern latitudes, acceleration of the global nitrogen cycle), and shifts in demand for forest and farm products. The global trade of biomass-derived commodities affects the link between consumption patterns and the land cover impact. Global greening confirms the immediacy of global change and may be associated with more or less biodiversity and diverse environmental and human consequences depending on local circumstances. Understanding causes, mechanisms, and implications of global greening requires integrated analyses spanning land use and management, demand for products of the terrestrial biosphere, and the atmosphere and climate. Understanding the pace and drivers of global greening matters crucially for assessing the future of the terrestrial C sink; ecological, economic, social, and cultural assessments of the bio-economy; and the preservation of ecosystems.

  7. Firm but Slippery Attachment of Deinococcus geothermalis

    PubMed Central

    Kolari, M.; Schmidt, U.; Kuismanen, E.; Salkinoja-Salonen, M. S.

    2002-01-01

    Bacterial biofilms impair the operation of many industrial processes. Deinococcus geothermalis is efficient primary biofilm former in paper machine water, functioning as an adhesion platform for secondary biofilm bacteria. It produces thick biofilms on various abiotic surfaces, but the mechanism of attachment is not known. High-resolution field-emission scanning electron microscopy and atomic force microscopy (AFM) showed peritrichous adhesion threads mediating the attachment of D. geothermalis E50051 to stainless steel and glass surfaces and cell-to-cell attachment, irrespective of the growth medium. Extensive slime matrix was absent from the D. geothermalis E50051 biofilms. AFM of the attached cells revealed regions on the cell surface with different topography, viscoelasticity, and adhesiveness, possibly representing different surface layers that were patchily exposed. We used oscillating probe techniques to keep the tip-biofilm interactions as small as possible. In spite of this, AFM imaging of living D. geothermalis E50051 biofilms in water resulted in repositioning but not in detachment of the surface-attached cells. The irreversibly attached cells did not detach when pushed with a glass capillary but escaped the mechanical force by sliding along the surface. Air drying eliminated the flexibility of attachment, but it resumed after reimmersion in water. Biofilms were evaluated for their strength of attachment. D. geothermalis E50051 persisted 1 h of washing with 0.2% NaOH or 0.5% sodium dodecyl sulfate, in contrast to biofilms of Burkholderia cepacia F28L1 or the well-characterized biofilm former Staphylococcus epidermidis O-47. Deinococcus radiodurans strain DSM 20539T also formed tenacious biofilms. This paper shows that D. geothermalis has firm but laterally slippery attachment not reported before for a nonmotile species. PMID:11948162

  8. Sunscreening Agents

    PubMed Central

    Martis, Jacintha; Shobha, V; Sham Shinde, Rutuja; Bangera, Sudhakar; Krishnankutty, Binny; Bellary, Shantala; Varughese, Sunoj; Rao, Prabhakar; Naveen Kumar, B.R.

    2013-01-01

    The increasing incidence of skin cancers and photodamaging effects caused by ultraviolet radiation has increased the use of sunscreening agents, which have shown beneficial effects in reducing the symptoms and reoccurrence of these problems. Many sunscreen compounds are in use, but their safety and efficacy are still in question. Efficacy is measured through indices, such as sun protection factor, persistent pigment darkening protection factor, and COLIPA guidelines. The United States Food and Drug Administration and European Union have incorporated changes in their guidelines to help consumers select products based on their sun protection factor and protection against ultraviolet radiation, whereas the Indian regulatory agency has not yet issued any special guidance on sunscreening agents, as they are classified under cosmetics. In this article, the authors discuss the pharmacological actions of sunscreening agents as well as the available formulations, their benefits, possible health hazards, safety, challenges, and proper application technique. New technologies and scope for the development of sunscreening agents are also discussed as well as the role of the physician in patient education about the use of these agents. PMID:23320122

  9. Firms growth dynamics, competition and power-law scaling

    NASA Astrophysics Data System (ADS)

    Gupta, Hari M.; Campanha, José R.

    2003-05-01

    We study the growth dynamics of the size of manufacturing firms considering competition and normal distribution of competency. We start with the fact that all components of the system struggle with each other for growth as happened in real competitive business world. The detailed quantitative agreement of the theory with empirical results of firms growth based on a large economic database spanning over 20 years is good with a single set of the parameters for all the curves. Further, the empirical data of the variation of the standard deviation of the growth rate with the size of the firm are in accordance with the present theory rather than a simple power law.

  10. Does microblogging convey firm-specific information? Evidence from China

    NASA Astrophysics Data System (ADS)

    Shen, Dehua; Li, Xiao; Xue, Mei; Zhang, Wei

    2017-09-01

    This paper investigates the impact of opening microblogging account in Sina Weibo on the diffusion of firm-specific information in Chinese stock market. With the unique sample of firms opening their official accounts, the empirical results show that this newly emerged information diffusion channel, i.e., Sina Weibo, plays an important role in conveying firm-specific information to the market. Generally speaking, these empirical findings have practical implications to securities regulators who have interest in monitoring the diffused information via social media.

  11. The historical impact of ISO 9000 on Lebanese firms.

    PubMed

    Mezher, Toufic; Ajam, Maher; Shehab, Mohamad

    2004-01-01

    The objective of this paper is to assess the impact of the new ISO 9001:2000 standard on the Quality Management Systems (QMS) of Lebanese firms that were already certified under ISO 9000:1994. To get an accurate feedback of stakeholders in a firm, three different questionnaires were developed and distributed to management, employees, and customers respectively. Empirical results indicate that ISO 9001:2000 has improved the QMS performance of Lebanese firms over that of the 1994 edition. Nevertheless, results showed that the new standard still has some weaknesses when it comes to improving suppliers' relationships and empowering employees.

  12. Antibiotic Agents

    MedlinePlus

    ... Work Contact Us ABOUT THE ISSUE What is Antibiotic Resistance? General Background Science of Resistance Glossary References POLICY ... for Adaptation Genetics and Drug Resistance Reservoirs of Antibiotic Resistance Project (ROAR) INTERNATIONAL CHAPTERS APUA Chapter Network Africa ...

  13. Bringing the Firms into Globalization Research: The Effects of Foreign Investment and Exports on Wages in Mexican Manufacturing Firms.

    PubMed

    Villarreal, Andrés; Sakamoto, Arthur

    2011-05-01

    Researchers specializing in organizations and labor markets have paid insufficient attention to the effects that foreign ownership of a firm and its orientation towards export production may have on the wages it pays to its workers. Using information from a nationally-representative sample of manufacturing firms in Mexico, a paradigmatic case of a developing country that is highly integrated into world markets, we find that foreign-owned and export-oriented firms pay considerably more than nationally-owned firms engaged in the production of goods for sale in the domestic market. Second, beyond paying higher wages to their workers, foreign-owned firms also raise the wages paid by domestic firms operating in the same regional labor markets. The wage premium in foreign and export-oriented firms cannot be explained by their size, industry, geographical location, productivity, use of advanced technology, or the sociodemographic composition of their workforce. We find evidence that wages in foreign-owned companies in Mexico are dependent on the country of origin of the capital investment. A greater difference between the industry-specific wages paid in the country of ownership and Mexico is associated with a higher wage premium in Mexican affiliates. Future work should strive to link information from foreign-owned affiliates with their parent companies abroad.

  14. What results when firms implement practices: the differential relationship between specific practices, firm financial performance, customer service, and quality.

    PubMed

    Gibson, Cristina B; Porath, Christine L; Benson, George S; Lawler, Edward E

    2007-11-01

    Previous research on organizational practices is replete with contradictory evidence regarding their effects. Here, the authors argue that these contradictory findings may have occurred because researchers have often examined complex practice combinations and have failed to investigate a broad variety of firm-level outcomes. Thus, past research may obscure important differential effects of specific practices on specific firm-level outcomes. Extending this research, the authors develop hypotheses about the effects of practices that (a) enable information sharing, (b) set boundaries, and (c) enable teams on 3 different firm-level outcomes: financial performance, customer service, and quality. Relationships are tested in a sample of observations from over 200 Fortune 1000 firms. Results indicate that information-sharing practices were positively related to financial performance 1 year following implementation of the practices, boundary-setting practices were positively related to firm-level customer service, and team-enabling practices were related to firm-level quality. No single set of practices predicted all 3 firm-level outcomes, indicating practice-specific effects. These findings help resolve the theoretical tension in the literature regarding the effects of organizational practices and offer guidance as to how to best target practices to increase specific work-related outcomes. Implications for theory, research, and practice are discussed.

  15. Bringing the Firms into Globalization Research: The Effects of Foreign Investment and Exports on Wages in Mexican Manufacturing Firms

    PubMed Central

    Villarreal, Andrés; Sakamoto, Arthur

    2011-01-01

    Researchers specializing in organizations and labor markets have paid insufficient attention to the effects that foreign ownership of a firm and its orientation towards export production may have on the wages it pays to its workers. Using information from a nationally-representative sample of manufacturing firms in Mexico, a paradigmatic case of a developing country that is highly integrated into world markets, we find that foreign-owned and export-oriented firms pay considerably more than nationally-owned firms engaged in the production of goods for sale in the domestic market. Second, beyond paying higher wages to their workers, foreign-owned firms also raise the wages paid by domestic firms operating in the same regional labor markets. The wage premium in foreign and export-oriented firms cannot be explained by their size, industry, geographical location, productivity, use of advanced technology, or the sociodemographic composition of their workforce. We find evidence that wages in foreign-owned companies in Mexico are dependent on the country of origin of the capital investment. A greater difference between the industry-specific wages paid in the country of ownership and Mexico is associated with a higher wage premium in Mexican affiliates. Future work should strive to link information from foreign-owned affiliates with their parent companies abroad. PMID:21566699

  16. Ecology Based Decentralized Agent Management System

    NASA Technical Reports Server (NTRS)

    Peysakhov, Maxim D.; Cicirello, Vincent A.; Regli, William C.

    2004-01-01

    The problem of maintaining a desired number of mobile agents on a network is not trivial, especially if we want a completely decentralized solution. Decentralized control makes a system more r e bust and less susceptible to partial failures. The problem is exacerbated on wireless ad hoc networks where host mobility can result in significant changes in the network size and topology. In this paper we propose an ecology-inspired approach to the management of the number of agents. The approach associates agents with living organisms and tasks with food. Agents procreate or die based on the abundance of uncompleted tasks (food). We performed a series of experiments investigating properties of such systems and analyzed their stability under various conditions. We concluded that the ecology based metaphor can be successfully applied to the management of agent populations on wireless ad hoc networks.

  17. An empirical examination of the influence of industry and firm drivers on the rate of internationalization by firms

    NASA Astrophysics Data System (ADS)

    Elango, B.

    A gradual shift in U.S. firms' 'center of gravity' toward international markets is taking place. This study seeks to explain which drivers are related to this push toward international markets by U.S. firms. In addressing internationalization, previous research has not focused on various drivers that influence the rate of internationalization. Drivers refer to forces, both within and outside the firm, that impact (both positively and negatively) a firm's extent of internationalization. The role of these drivers on the rate of internationalization, though acknowledged in the literature, is yet to be validated through empirical research. This research seeks to narrow the gap in the literature by testing the various relationships among industry drivers, firm drivers, and the rate of internationalization. The objectives of this study are: (A) To develop a conceptual framework that takes into account various forces that influence the internationalization strategy of a firm; (B) To examine empirically (a) the influence of industry drivers on the rate of internationalization pursued by firms; and, (b) the influence of firm drivers on the rate of internationalization by firms. The sample for this study consists of 158 large U.S.- based multinational firms drawn from seven different industries. Data for the study is gathered from a variety of sources including the U.S. Department of Commerce, Bureau of Economic Analysis; COMPUSTAT; and WORLDSCOPE databases. Set-wise regression models were used for data analysis. This study found that global market growth rate, domestic market growth rate, relative size of domestic market to international market, employee productivity, administrative investments, as well as new plant and equipment influences the international strategy of firms. This study explains about 24 percent of the variance of the rate of internationalization. This research finding is contributory to our existing understanding of internationalization in many ways

  18. Intel takes a stake in ultraviolet-lithography firm

    NASA Astrophysics Data System (ADS)

    Stafford, Ned

    2012-08-01

    The world's biggest computer-chip maker, Intel Corporation, has signed a major agreement with Dutch lithography firm ASML Holding to collaborate on developing the next generation of technology for manufacturing semiconductor chips.

  19. Globetrotting firms: Canada's health biotechnology collaborations with developing countries.

    PubMed

    Ray, Monali; Daar, Abdallah S; Singer, Peter A; Thorsteinsdóttir, Halla

    2009-09-01

    A survey of Canadian biotech firms reveals that their biotech collaborations with developing countries are not only significant but also increasingly reciprocal in terms of the exchange of financial resources and technological know-how.

  20. Autonomous sensor manager agents (ASMA)

    NASA Astrophysics Data System (ADS)

    Osadciw, Lisa A.

    2004-04-01

    Autonomous sensor manager agents are presented as an algorithm to perform sensor management within a multisensor fusion network. The design of the hybrid ant system/particle swarm agents is described in detail with some insight into their performance. Although the algorithm is designed for the general sensor management problem, a simulation example involving 2 radar systems is presented. Algorithmic parameters are determined by the size of the region covered by the sensor network, the number of sensors, and the number of parameters to be selected. With straight forward modifications, this algorithm can be adapted for most sensor management problems.

  1. Antidiabetic Agents.

    ERIC Educational Resources Information Center

    Plummer, Nancy; Michael, Nancy, Ed.

    This module on antidiabetic agents is intended for use in inservice or continuing education programs for persons who administer medications in long-term care facilities. Instructor information, including teaching suggestions, and a listing of recommended audiovisual materials and their sources appear first. The module goal and objectives are then…

  2. Antidiabetic Agents.

    ERIC Educational Resources Information Center

    Plummer, Nancy; Michael, Nancy, Ed.

    This module on antidiabetic agents is intended for use in inservice or continuing education programs for persons who administer medications in long-term care facilities. Instructor information, including teaching suggestions, and a listing of recommended audiovisual materials and their sources appear first. The module goal and objectives are then…

  3. Global evidence on the distribution of firm growth rates

    NASA Astrophysics Data System (ADS)

    Williams, Michael A.; Pinto, Brijesh P.; Park, David

    2015-08-01

    The consensus finding in the literature is that the distribution of firm growth rates is best approximated by the Laplace distribution, a particular case of the Subbotin, or exponential power, family of probability distributions. Using a richer database than prior studies and testing for more theoretical distributions, we find that the distribution of firm growth rates is best approximated by the heavier-tailed Cauchy distribution.

  4. [Unconventional antidiabetic agents].

    PubMed

    Rustenbeck, Ingo

    2007-04-01

    The current pharmacological therapy of type 2 diabetes reduces the risk of diabetic complications, but is not able to achieve a long-lasting normalization of the metabolic disorder. Thus diabetic patients in increasing numbers are taking dietary supplements and herbs from which they expect additional health benefits. These unconventional antidiabetic agents consist mainly in trace metals like chromium, vanadium and zinc and a heterogeneous group of traditionally used antidiabetic herbs (e. g. Momordica charantia, Gymnema sylvestre, Trigonella foenum-graecum) often derived from the ayurvedic medicine. In this overview the current evidence for the antidiabetic effect is presented. The trace elements chromium and vanadium have a number of potentially antidiabetic actions in vitro, however, the results obtained with diabetic patients are not convincing so far. Similarly, the available data on the therapeutic use of herbs suggest that in principle a number of them possess a blood glucose-lowering effect, but at present no firm conclusions as to their efficacy and safety can be made. To set up reliable dose-effect relationships requires the identification of the relevant antidiabetic molecules as was apparently achieved by isolating 4-hydroxyisoleucine from the seeds of T. foenum-graecum. This requirement is also valid in the case of the antidiabetic action of cinnamon. Coffee and a moderate alcohol consumption were found to be surprisingly effective in lowering the risk of type 2 diabetes manifestation, their effect being roughly equal to that of conventional drugs used in diabetes prevention trials. Diabetic patients should inform their physician about the use of unconventional agents and should be warned against uncontrolled starting or stopping their use.

  5. Evolutionary model of the growth and size of firms

    NASA Astrophysics Data System (ADS)

    Kaldasch, Joachim

    2012-07-01

    The key idea of this model is that firms are the result of an evolutionary process. Based on demand and supply considerations the evolutionary model presented here derives explicitly Gibrat's law of proportionate effects as the result of the competition between products. Applying a preferential attachment mechanism for firms, the theory allows to establish the size distribution of products and firms. Also established are the growth rate and price distribution of consumer goods. Taking into account the characteristic property of human activities to occur in bursts, the model allows also an explanation of the size-variance relationship of the growth rate distribution of products and firms. Further the product life cycle, the learning (experience) curve and the market size in terms of the mean number of firms that can survive in a market are derived. The model also suggests the existence of an invariant of a market as the ratio of total profit to total revenue. The relationship between a neo-classic and an evolutionary view of a market is discussed. The comparison with empirical investigations suggests that the theory is able to describe the main stylized facts concerning the size and growth of firms.

  6. Network analysis to detect common strategies in Italian foreign direct investment

    NASA Astrophysics Data System (ADS)

    De Masi, G.; Giovannetti, G.; Ricchiuti, G.

    2013-03-01

    In this paper we reconstruct and discuss the network of Italian firms investing abroad, exploiting information from complex network analysis. This method, detecting the key nodes of the system (both in terms of firms and countries of destination), allows us to single out the linkages among firms without ex-ante priors. Moreover, through the examination of affiliates’ economic activity, it allows us to highlight different internationalization strategies of “leaders” in different manufacturing sectors.

  7. 48-Week Efficacy and Safety of Dolutegravir Relative to Commonly Used Third Agents in Treatment-Naive HIV-1–Infected Patients: A Systematic Review and Network Meta-Analysis

    PubMed Central

    Patel, Dipen A.; Snedecor, Sonya J.; Tang, Wing Yu; Sudharshan, Lavanya; Lim, Jessica W.; Cuffe, Robert; Pulgar, Sonia; Gilchrist, Kim A.; Camejo, Rodrigo Refoios; Stephens, Jennifer; Nichols, Garrett

    2014-01-01

    Background A network meta-analysis can provide estimates of relative efficacy for treatments not directly studied in head-to-head randomized controlled trials. We estimated the relative efficacy and safety of dolutegravir (DTG) versus third agents currently recommended by guidelines, including ritonavir-boosted atazanavir (ATV/r), ritonavir-boosted darunavir (DRV/r), efavirenz (EFV), cobicistat-boosted elvitegravir (EVG/c), ritonavir-boosted lopinavir (LPV/r), raltegravir (RAL), and rilpivirine (RPV), in treatment-naive HIV-1–infected patients. Methods A systematic review of published literature was conducted to identify phase 3/4 randomized controlled clinical trials (up to August 2013) including at least one third agent of interest in combination with a backbone nucleoside reverse transcriptase inhibitor (NRTI) regimen. Bayesian fixed-effect network meta-analysis models adjusting for the type of nucleoside reverse transcriptase inhibitor backbone (tenofovir disoproxil fumarate/emtricitabine [TDF/FTC] or abacavir/lamivudine [ABC/3TC]) were used to evaluate week 48 efficacy (HIV-RNA suppression to <50 copies/mL and change in CD4+ cells/µL) and safety (lipid changes, adverse events, and discontinuations due to adverse events) of DTG relative to all other treatments. Sensitivity analyses assessing the impact of NRTI treatment adjustment and random-effects models were performed. Results Thirty-one studies including 17,000 patients were combined in the analysis. Adjusting for the effect of NRTI backbone, treatment with DTG resulted in significantly higher odds of virologic suppression (HIV RNA<50 copies/mL) and increase in CD4+ cells/µL versus ATV/r, DRV/r, EFV, LPV/r, and RPV. Dolutegravir had better or equivalent changes in total cholesterol, LDL, triglycerides, and lower odds of adverse events and discontinuation due to adverse events compared to all treatments. Random-effects and unadjusted models resulted in similar conclusions. Conclusion Three clinical

  8. A Conceptual Framework for Representing Human Behavior Characteristics in a System of Systems Agent-based Survivability Simulation-Intelligent Networks

    DTIC Science & Technology

    2014-10-17

    current practice of using arbitrary interleaving models such as labeled transition systems. 1.4. Project Objectives The following tasks are performed...based upon the practical scenario and node based inputs at a particular time interval. Actor-network theory (ANT) from Bruno Latour (1992) provides...and recommendation derived from direct or indirect interactions for “ sociable ” purposes (Theodorakopoulous & Baras, 2012). In MANETs, some metrics

  9. Discriminating Micropathogen Lineages and Their Reticulate Evolution through Graph Theory-Based Network Analysis: The Case of Trypanosoma cruzi, the Agent of Chagas Disease

    PubMed Central

    Arnaud-Haond, Sophie; Moalic, Yann; Barnabé, Christian; Ayala, Francisco José; Tibayrenc, Michel

    2014-01-01

    Micropathogens (viruses, bacteria, fungi, parasitic protozoa) share a common trait, which is partial clonality, with wide variance in the respective influence of clonality and sexual recombination on the dynamics and evolution of taxa. The discrimination of distinct lineages and the reconstruction of their phylogenetic history are key information to infer their biomedical properties. However, the phylogenetic picture is often clouded by occasional events of recombination across divergent lineages, limiting the relevance of classical phylogenetic analysis and dichotomic trees. We have applied a network analysis based on graph theory to illustrate the relationships among genotypes of Trypanosoma cruzi, the parasitic protozoan responsible for Chagas disease, to identify major lineages and to unravel their past history of divergence and possible recombination events. At the scale of T. cruzi subspecific diversity, graph theory-based networks applied to 22 isoenzyme loci (262 distinct Multi-Locus-Enzyme-Electrophoresis -MLEE) and 19 microsatellite loci (66 Multi-Locus-Genotypes -MLG) fully confirms the high clustering of genotypes into major lineages or “near-clades”. The release of the dichotomic constraint associated with phylogenetic reconstruction usually applied to Multilocus data allows identifying putative hybrids and their parental lineages. Reticulate topology suggests a slightly different history for some of the main “near-clades”, and a possibly more complex origin for the putative hybrids than hitherto proposed. Finally the sub-network of the near-clade T. cruzi I (28 MLG) shows a clustering subdivision into three differentiated lesser near-clades (“Russian doll pattern”), which confirms the hypothesis recently proposed by other investigators. The present study broadens and clarifies the hypotheses previously obtained from classical markers on the same sets of data, which demonstrates the added value of this approach. This underlines the

  10. Discriminating micropathogen lineages and their reticulate evolution through graph theory-based network analysis: the case of Trypanosoma cruzi, the agent of Chagas disease.

    PubMed

    Arnaud-Haond, Sophie; Moalic, Yann; Barnabé, Christian; Ayala, Francisco José; Tibayrenc, Michel

    2014-01-01

    Micropathogens (viruses, bacteria, fungi, parasitic protozoa) share a common trait, which is partial clonality, with wide variance in the respective influence of clonality and sexual recombination on the dynamics and evolution of taxa. The discrimination of distinct lineages and the reconstruction of their phylogenetic history are key information to infer their biomedical properties. However, the phylogenetic picture is often clouded by occasional events of recombination across divergent lineages, limiting the relevance of classical phylogenetic analysis and dichotomic trees. We have applied a network analysis based on graph theory to illustrate the relationships among genotypes of Trypanosoma cruzi, the parasitic protozoan responsible for Chagas disease, to identify major lineages and to unravel their past history of divergence and possible recombination events. At the scale of T. cruzi subspecific diversity, graph theory-based networks applied to 22 isoenzyme loci (262 distinct Multi-Locus-Enzyme-Electrophoresis -MLEE) and 19 microsatellite loci (66 Multi-Locus-Genotypes -MLG) fully confirms the high clustering of genotypes into major lineages or "near-clades". The release of the dichotomic constraint associated with phylogenetic reconstruction usually applied to Multilocus data allows identifying putative hybrids and their parental lineages. Reticulate topology suggests a slightly different history for some of the main "near-clades", and a possibly more complex origin for the putative hybrids than hitherto proposed. Finally the sub-network of the near-clade T. cruzi I (28 MLG) shows a clustering subdivision into three differentiated lesser near-clades ("Russian doll pattern"), which confirms the hypothesis recently proposed by other investigators. The present study broadens and clarifies the hypotheses previously obtained from classical markers on the same sets of data, which demonstrates the added value of this approach. This underlines the potential of graph

  11. A multilevel investigation of motivational cultural intelligence, organizational diversity climate, and cultural sales: evidence from U.S. real estate firms.

    PubMed

    Chen, Xiao-Ping; Liu, Dong; Portnoy, Rebecca

    2012-01-01

    Adopting a multilevel theoretical framework, the authors examined how motivational cultural intelligence influences individual cultural sales--the number of housing transactions occurring between people of different cultural origins. Data from 305 real estate agents employed at 26 real estate firms in the United States demonstrated that an individual's motivational cultural intelligence is positively related to his or her cultural sales. This positive relationship is enhanced by the firm's motivational cultural intelligence and diversity climate. The authors discuss the theoretical and practical implications of their findings in a workplace context that involves cross-cultural interpersonal interactions.

  12. A study of knowledge supernetworks and network robustness in different business incubators

    NASA Astrophysics Data System (ADS)

    Zhang, Haihong; Wu, Wenqing; Zhao, Liming

    2016-04-01

    As the most important intangible resource of the new generation of business incubators, knowledge has been studied extensively, particularly with respect to how it spreads among incubating firms through knowledge networks. However, these homogeneous networks do not adequately describe the heterogeneity of incubating firms in different types of business incubators. To solve the problem of heterogeneity, the notion of a knowledge supernetwork has been used both to construct a knowledge interaction model among incubating firms and to distinguish social network relationships from knowledge network relationships. The process of knowledge interaction and network evolution can then be simulated with a few rules for incubating firms regarding knowledge innovation/absorption, social network connection, and entry and exit, among other aspects. Knowledge and networks have been used as performance indicators to evaluate the evolution of knowledge supernetworks. Moreover, we study the robustness of incubating firms' social networks by employing four types of attack strategies. Based on our simulation results, we conclude that there have been significant knowledge interaction and network evolution among incubating firms on a periodic basis and that both specialized and diversified business incubators have every advantage necessary in terms of both knowledge and networks to cultivate start-up companies. As far as network robustness is concerned, there is no obvious difference between the two types of business incubators with respect to the stability of their network structures, but specialized business incubators have stronger network communication abilities than diversified business incubators.

  13. Internal labor markets and firm-specific determination of earnings in the presence of immigrant workers.

    PubMed

    Zweimuller, J; Winter-ebmer, R

    1995-01-01

    "In this paper we study earnings determination at the firm level in Austria. We distinguish firms who employ immigrant workers and those who do not. By using a switching regressions model we find that native workers in firms with immigrant employees face rising earnings-tenure profiles whereas natives in other firms do not."

  14. A Novel Anti-Hepatitis C Virus and Antiproliferative Agent Alters Metabolic Networks in HepG2 and Hep3B Cells

    PubMed Central

    Keogh, Adrian; Şenkardeş, Sevil; Idle, Jeffrey R.; Küçükgüzel, Ş. Güniz; Beyoğlu, Diren

    2017-01-01

    A series of novel diflunisal hydrazide-hydrazones has been reported together with their anti-hepatitis C virus and antiproliferative activities in a number of human hepatoma cell lines. However, the mechanisms underlying the efficacy of these agents remain unclear. It was chosen to investigate the lead diflunisal hydrazide-hydrazone, 2′,4′-difluoro-4-hydroxy-N′- [(pyridin-2-yl)methylidene]biphenyl-3-carbohydrazide (compound 3b), in two cultured human hepatoma cell lines—HepG2 and Hep3B—using a metabolomic protocol aimed at uncovering any effects of this agent on cellular metabolism. One sub-therapeutic concentration (2.5 μM) and one close to the IC50 for antimitotic effect (10 μM), after 72 h in cell culture, were chosen for both compound 3b and its inactive parent compound diflusinal as a control. A GCMS-based metabolomic investigation was performed on cell lysates after culture for 24 h. The intracellular levels of a total of 42 metabolites were found to be statistically significantly altered in either HepG2 or Hep3B cells, only eight of which were affected in both cell lines. It was concluded that compound 3b affected the following pathways—purine and pyrimidine catabolism, the glutathione cycle, and energy metabolism through glycolysis and the pentose phosphate pathway. Although the metabolomic findings occurred after 24 h in culture, significant cytotoxicity of compound 3b to both HepG2 and Hep3B cells at 10 μM were reported not to occur until 72 h in culture. These observations show that metabolomics can provide mechanistic insights into the efficacy of novel drug candidates prior to the appearance of their pharmacological effect. PMID:28574427

  15. Analyzing Thiol-Dependent Redox Networks in the Presence of Methylene Blue and Other Antimalarial Agents with RT-PCR-Supported in silico Modeling

    PubMed Central

    Zirkel, J.; Cecil, A.; Schäfer, F.; Rahlfs, S.; Ouedraogo, A.; Xiao, K.; Sawadogo, S.; Coulibaly, B.; Becker, K.; Dandekar, T.

    2012-01-01

    Background In the face of growing resistance in malaria parasites to drugs, pharmacological combination therapies are important. There is accumulating evidence that methylene blue (MB) is an effective drug against malaria. Here we explore the biological effects of both MB alone and in combination therapy using modeling and experimental data. Results We built a model of the central metabolic pathways in P. falciparum. Metabolic flux modes and their changes under MB were calculated by integrating experimental data (RT-PCR data on mRNAs for redox enzymes) as constraints and results from the YANA software package for metabolic pathway calculations. Several different lines of MB attack on Plasmodium redox defense were identified by analysis of the network effects. Next, chloroquine resistance based on pfmdr/and pfcrt transporters, as well as pyrimethamine/sulfadoxine resistance (by mutations in DHF/DHPS), were modeled in silico. Further modeling shows that MB has a favorable synergism on antimalarial network effects with these commonly used antimalarial drugs. Conclusions Theoretical and experimental results support that methylene blue should, because of its resistance-breaking potential, be further tested as a key component in drug combination therapy efforts in holoendemic areas. PMID:23236254

  16. 1985 Firm Displacement Power Rate Proposal : Administrator's Record of Decision.

    SciTech Connect

    United States. Bonneville Power Administration.

    1986-06-01

    Bonneville Power Administration (BPA) first proposed a Firm Displacement Power (FD) rate in September 1984 as part of the initial 1985 wholesale rate proposal. The proposed FD rate was part of a package of rates designed to provide BPA flexibility in marketing its surplus firm power in a competitive and uncertain market. Believing that the rate needed further study, on December 11, 1984, BPA withdrew the proposed FD rate from consideration in the 1985 rate proceeding. BPA continued to pursue discussions with Pacific Northwest (PNW) and Pacific Southwest (PSW) utilities regarding potential sales of PNW surplus firm power to California markets. When several utilities expressed interest in the FD concept (in which BPA would sell its surplus firm power on a long-term basis to PNW utilities, who would use the FD power to serve their regional load and make a long-term firm sale of their own generating resources to the PSW), BPA held a series of weekly informal public meetings. The series of meetings, which began in June 1985, included discussion of contract issues. After assessing the discussions held at the first four meetings, BPA announced at the July 12, 1985, meeting that the FD rate would be developed in a hearing process pursuant to section 7(i) of the Pacific Northwest Electric Power Planning and Conservation Act (Pacific Northwest Power Act).

  17. Social firms: sustainable employment for people with mental illness.

    PubMed

    Williams, Anne; Fossey, Ellie; Harvey, Carol

    2012-01-01

    Social firms or enterprises aim to offer sustainable employment in supportive workplaces for people who are disadvantaged in the labour market. Therefore, this study sought to explore employees' views in one social firm about the features of their workplace that they found supportive. Seven employees were recruited, all of whom experienced persistent mental illness, and had worked in this social firm for between eleven months and six years. A semi-structured interview, the Work Environment Impact Scale (version 2.0), was used to explore participants' views of their workplace and to rate how its physical and social characteristics impacted them. Participants also rated their job satisfaction with a modified Indiana Job Satisfaction Scale. Features of the social firm workplace identified by these employees as contributing to their sustained employment and satisfaction were the rewards, task demands, work schedule, and workplace interactions with supervisors and other co-workers. From their views, guiding principles for the development of supportive workplaces and evaluation of their capacity to afford sustainable employment were derived. This study adds to current knowledge about workplace supports from an employee perspective, and is of relevance for informing future social firm development, workplace design and evaluation.

  18. Intelligent Agent Feasibility Study. Volume 1: Agent-based System Technology

    DTIC Science & Technology

    1998-02-01

    ambitious in its scope. In OAA (Moran, Cheyer, Julia , Martin, 10 & Park, 1997), agents can operate on multiple platforms across a network, new agents can be...find the source and best price for a given item. This area of electronic commerce has been an active area for research in agent-based systems ( Chavez ...D. (1993). Towards a taxonomy of multi-agent systems. International Journal of Man-Machine Studies 36, 689-704. Chavez , A., Dreilinger, D., Guttman, R

  19. KGB agents

    NASA Astrophysics Data System (ADS)

    Gaina, Alex

    A short story is reported in which the activity of Communist Party of the USSR and secret KGB agents, which were payed by the State, in view of controlling of the conscience of population. The story reffers to the Physics Department of the Moscow University, Planing Institute of the Gosplan of Moldavian S.S.R. and Chishinau Technical University (actually: Technical University of Moldova), where the author has worked during Soviet times. Almost every 6-th citizen in the USSR was engaged in this activity, while actually the former communists rule in the Republic of Moldova.

  20. Multi-Agent System for Resource Reliability

    DTIC Science & Technology

    2007-11-02

    1 research and development of a prototype for network resource reliability has laid the groundwork for the Phase 2 implementation of MASRR, a Multi - Agent System for Resource Reliability, and its eventual commercialization.

  1. The trans-species core SELF: the emergence of active cultural and neuro-ecological agents through self-related processing within subcortical-cortical midline networks.

    PubMed

    Panksepp, Jaak; Northoff, Georg

    2009-03-01

    The nature of "the self" has been one of the central problems in philosophy and more recently in neuroscience. This raises various questions: (i) Can we attribute a self to animals? (ii) Do animals and humans share certain aspects of their core selves, yielding a trans-species concept of self? (iii) What are the neural processes that underlie a possible trans-species concept of self? (iv) What are the developmental aspects and do they result in various levels of self-representation? Drawing on recent literature from both human and animal research, we suggest a trans-species concept of self that is based upon what has been called a "core-self" which can be described by self-related processing (SRP) as a specific mode of interaction between organism and environment. When we refer to specific neural networks, we will here refer to the underlying system as the "core-SELF." The core-SELF provides primordial neural coordinates that represent organisms as living creatures-at the lowest level this elaborates interoceptive states along with raw emotional feelings (i.e., the intentions in action of a primordial core-SELF) while higher medial cortical levels facilitate affective-cognitive integration (yielding a fully-developed nomothetic core-self). Developmentally, SRP allows stimuli from the environment to be related and linked to organismic needs, signaled and processed within core-self structures within subcorical-cortical midline structures (SCMS) that provide the foundation for epigenetic emergence of ecologically framed, higher idiographic forms of selfhood across different individuals within a species. These functions ultimately operate as a coordinated network. We postulate that core SRP operates automatically, is deeply affective, and is developmentally and epigenetically connected to sensory-motor and higher cognitive abilities. This core-self is mediated by SCMS, embedded in visceral and instinctual representations of the body that are well integrated with basic

  2. Productivity and safety in worker cooperatives and conventional firms.

    PubMed

    Grunberg, L; Everard, J; O'Toole, M

    1984-01-01

    This paper examines the relationship between productivity and workers' safety in firms characterized by very different types of relations in production. Arguments are developed to explain why worker cooperatives are expected to have higher productivity and lower accident rates than conventional capitalist firms. Workers who own and control their firms are expected to have a greater incentive to be efficient and a greater ability to safeguard their health than workers employed under hierarchical and alienating conditions. The hypotheses are tested by comparing carefully matched conventional and cooperative plywood companies. Preliminary results suggest that while cooperatives may be more productive they are not safer, indicating the limits of the isolated cooperative form in capitalist market economies.

  3. Kinetics of moisturizing and firming effects of cosmetic formulations.

    PubMed

    Xhauflaire-Uhoda, E; Fontaine, K; Piérard, G E

    2008-04-01

    The assessment of cosmetic efficacy is rarely performed in studies comparing different concentrations of active compounds. The aim of the present study was to determine the skin hydrating and the skin firming dose-response effects of cosmetic formulations enriched in compounds derived from algae and fish collagen. A series of factors were studied including the type of formulation (cream or serum), the concentration in active ingredients, the effect of repetitive applications, as well as any residual effect of the formulations after stopping their applications. The serum enriched in marine compounds showed a better moisturizing effect in short term. The cream appeared more active later, particularly following repeat applications. A sustained tensor (firming) effect was observed during treatment with both the lotion and the cream. However, no remnant firming effect was perceived after stopping treatment.

  4. Size distribution of Portuguese firms between 2006 and 2012

    NASA Astrophysics Data System (ADS)

    Pascoal, Rui; Augusto, Mário; Monteiro, A. M.

    2016-09-01

    This study aims to describe the size distribution of Portuguese firms, as measured by annual sales and total assets, between 2006 and 2012, giving an economic interpretation for the evolution of the distribution along the time. Three distributions are fitted to data: the lognormal, the Pareto (and as a particular case Zipf) and the Simplified Canonical Law (SCL). We present the main arguments found in literature to justify the use of distributions and emphasize the interpretation of SCL coefficients. Methods of estimation include Maximum Likelihood, modified Ordinary Least Squares in log-log scale and Nonlinear Least Squares considering the Levenberg-Marquardt algorithm. When applying these approaches to Portuguese's firms data, we analyze if the evolution of estimated parameters in both lognormal power and SCL is in accordance with the known existence of a recession period after 2008. This is confirmed for sales but not for assets, leading to the conclusion that the first variable is a best proxy for firm size.

  5. Security Measures to Protect Mobile Agents

    NASA Astrophysics Data System (ADS)

    Dadhich, Piyanka; Govil, M. C.; Dutta, Kamlesh

    2010-11-01

    The security issues of mobile agent systems have embarrassed its widespread implementation. Mobile agents that move around the network are not safe because the remote hosts that accommodate the agents initiates all kinds of attacks. These hosts try to analyze the agent's decision logic and their accumulated data. So, mobile agent security is the most challenging unsolved problems. The paper analyzes various security measures deeply. Security especially the attacks performed by hosts to the visiting mobile agent (the malicious hosts problem) is a major obstacle that prevents mobile agent technology from being widely adopted. Being the running environment for mobile agent, the host has full control over them and could easily perform many kinds of attacks against them.

  6. Firm size distribution and mobility of the top 500 firms in China, the United States and the world

    NASA Astrophysics Data System (ADS)

    Guo, Jinzhong; Xu, Qi; Chen, Qinghua; Wang, Yougui

    2013-07-01

    This paper considers the macroscopic and microscopic statistical features of the top 500 firms in China, the United States and the world, denoted as China 500 (CH500), Fortune 500 (US500) and Fortune Global 500 (FG500). From a macroscopic perspective, the firm size distribution of each category, when measured by revenue, is steadily distributed over the observed period, even during periods of financial crises. As is evidenced by the Gini coefficient, divergences between firm scales are most significant for the CH500. From a microscopic perspective, the underlying micro-dynamics are volatile and often turbulent due to the exit and entry of firms as well as shifts in their revenues and ranks. Such fluctuations, or mobility, are visualized in rank/revenue/share clocks. We also propose a revenue/rank/share mobility index that is a quantitative measurement of mobility. Among these, we find that the share mobility acts as an effective indicator of economic status; where there is a share mobility spike, there is an ailing economy. The share mobility indexes indicate that the 2008 Financial Crisis had little impact on the Chinese economy, while it triggered violent changes in the top 500 firms in the United States and the world.

  7. NISAC Agent Based Laboratory for Economics

    SciTech Connect

    Downes, Paula; Davis, Chris; Eidson, Eric; Ehlen, Mark; Gieseler, Charles; Harris, Richard

    2006-10-11

    The software provides large-scale microeconomic simulation of complex economic and social systems (such as supply chain and market dynamics of businesses in the US economy) and their dependence on physical infrastructure systems. The system is based on Agent simulation, where each entity of inteest in the system to be modeled (for example, a Bank, individual firms, Consumer households, etc.) is specified in a data-driven sense to be individually repreented by an Agent. The Agents interact using rules of interaction appropriate to their roles, and through those interactions complex economic and social dynamics emerge. The software is implemented in three tiers, a Java-based visualization client, a C++ control mid-tier, and a C++ computational tier.

  8. The Structure and Evolution of Buyer-Supplier Networks

    PubMed Central

    Mizuno, Takayuki; Souma, Wataru; Watanabe, Tsutomu

    2014-01-01

    In this paper, we investigate the structure and evolution of customer-supplier networks in Japan using a unique dataset that contains information on customer and supplier linkages for more than 500,000 incorporated non-financial firms for the five years from 2008 to 2012. We find, first, that the number of customer links is unequal across firms; the customer link distribution has a power-law tail with an exponent of unity (i.e., it follows Zipf's law). We interpret this as implying that competition among firms to acquire new customers yields winners with a large number of customers, as well as losers with fewer customers. We also show that the shortest path length for any pair of firms is, on average, 4.3 links. Second, we find that link switching is relatively rare. Our estimates indicate that the survival rate per year for customer links is 92 percent and for supplier links 93 percent. Third and finally, we find that firm growth rates tend to be more highly correlated the closer two firms are to each other in a customer-supplier network (i.e., the smaller is the shortest path length for the two firms). This suggests that a non-negligible portion of fluctuations in firm growth stems from the propagation of microeconomic shocks – shocks affecting only a particular firm – through customer-supplier chains. PMID:25000368

  9. The structure and evolution of buyer-supplier networks.

    PubMed

    Mizuno, Takayuki; Souma, Wataru; Watanabe, Tsutomu

    2014-01-01

    In this paper, we investigate the structure and evolution of customer-supplier networks in Japan using a unique dataset that contains information on customer and supplier linkages for more than 500,000 incorporated non-financial firms for the five years from 2008 to 2012. We find, first, that the number of customer links is unequal across firms; the customer link distribution has a power-law tail with an exponent of unity (i.e., it follows Zipf's law). We interpret this as implying that competition among firms to acquire new customers yields winners with a large number of customers, as well as losers with fewer customers. We also show that the shortest path length for any pair of firms is, on average, 4.3 links. Second, we find that link switching is relatively rare. Our estimates indicate that the survival rate per year for customer links is 92 percent and for supplier links 93 percent. Third and finally, we find that firm growth rates tend to be more highly correlated the closer two firms are to each other in a customer-supplier network (i.e., the smaller is the shortest path length for the two firms). This suggests that a non-negligible portion of fluctuations in firm growth stems from the propagation of microeconomic shocks - shocks affecting only a particular firm - through customer-supplier chains.

  10. Exploration decisions and firms in the mineral industries

    USGS Publications Warehouse

    Attanasi, E.D.

    1981-01-01

    The purpose of this paper is to demonstrate how physical characteristics of deposits and results of past exploration enter future exploration decisions. A proposed decision model is presented that is consistent with a set of primitive probabilistic assumptions associated with deposit size distributions and discoverability. Analysis of optimal field exploration strategy showed the likely firm responses to alternative exploration taxes and effects on the distribution of future discoveries. Examination of the probabilistic elements of the decision model indicates that changes in firm expectations associated with the distribution of deposits cannot be totally offset by changes in economic variables. ?? 1981.

  11. Row erupts over US firm's plan to import nuclear waste

    NASA Astrophysics Data System (ADS)

    Gwynne, Peter

    2008-06-01

    A controversy is brewing in the US over a plan by a firm in Utah to import, process and dispose of 20 000 tonnes of low-level radioactive waste from decommissioned nuclear reactors built in Italy by American companies. EnergySolutions intends to recycle some of this waste at a site near Oak Ridge, Tennessee, so that it can be re-used as shielding blocks in nuclear plants. The firm then wants to dispose of the remaining radioactive material at a site in Clive, Utah, where over 90% of low-level radioactive waste generated in the US is currently buried.

  12. Metallic nanowire networks

    DOEpatents

    Song, Yujiang; Shelnutt, John A.

    2012-11-06

    A metallic nanowire network synthesized using chemical reduction of a metal ion source by a reducing agent in the presence of a soft template comprising a tubular inverse micellar network. The network of interconnected polycrystalline nanowires has a very high surface-area/volume ratio, which makes it highly suitable for use in catalytic applications.

  13. Applying temporal network analysis to the venture capital market

    NASA Astrophysics Data System (ADS)

    Zhang, Xin; Feng, Ling; Zhu, Rongqian; Stanley, H. Eugene

    2015-10-01

    Using complex network theory to study the investment relationships of venture capital firms has produced a number of significant results. However, previous studies have often neglected the temporal properties of those relationships, which in real-world scenarios play a pivotal role. Here we examine the time-evolving dynamics of venture capital investment in China by constructing temporal networks to represent (i) investment relationships between venture capital firms and portfolio companies and (ii) the syndication ties between venture capital investors. The evolution of the networks exhibits rich variations in centrality, connectivity and local topology. We demonstrate that a temporal network approach provides a dynamic and comprehensive analysis of real-world networks.

  14. Profound Morphological Changes in the Erythrocytes and Fibrin Networks of Patients with Hemochromatosis or with Hyperferritinemia, and Their Normalization by Iron Chelators and Other Agents

    PubMed Central

    Pretorius, Etheresia; Bester, Janette; Vermeulen, Natasha; Lipinski, Boguslaw; Gericke, George S.; Kell, Douglas B.

    2014-01-01

    It is well-known that individuals with increased iron levels are more prone to thrombotic diseases, mainly due to the presence of unliganded iron, and thereby the increased production of hydroxyl radicals. It is also known that erythrocytes (RBCs) may play an important role during thrombotic events. Therefore the purpose of the current study was to assess whether RBCs had an altered morphology in individuals with hereditary hemochromatosis (HH), as well as some who displayed hyperferritinemia (HF). Using scanning electron microscopy, we also assessed means by which the RBC and fibrin morphology might be normalized. An important objective was to test the hypothesis that the altered RBC morphology was due to the presence of excess unliganded iron by removing it through chelation. Very striking differences were observed, in that the erythrocytes from HH and HF individuals were distorted and had a much greater axial ratio compared to that accompanying the discoid appearance seen in the normal samples. The response to thrombin, and the appearance of a platelet-rich plasma smear, were also markedly different. These differences could largely be reversed by the iron chelator desferal and to some degree by the iron chelator clioquinol, or by the free radical trapping agents salicylate or selenite (that may themselves also be iron chelators). These findings are consistent with the view that the aberrant morphology of the HH and HF erythrocytes is caused, at least in part, by unliganded (‘free’) iron, whether derived directly via raised ferritin levels or otherwise, and that lowering it or affecting the consequences of its action may be of therapeutic benefit. The findings also bear on the question of the extent to which accepting blood donations from HH individuals may be desirable or otherwise. PMID:24416376

  15. Markets on Networks

    NASA Astrophysics Data System (ADS)

    Toroczkai, Zoltan; Anghel, Marian; Bassler, Kevin; Korniss, Gyorgy

    2003-03-01

    The dynamics of human, and most biological populations is characterized by competition for resources. By its own nature, this dynamics creates the group of "elites", formed by those agents who have strategies that are the most successful in the given situation, and therefore the rest of the agents will tend to follow, imitate, or interact with them, creating a social structure of leadership in the agent society. These inter-agent communications generate a complex social network with small-world character which itself forms the substrate for a second network, the action network. The latter is a highly dynamic, adaptive, directed network, defined by those inter-agent communication links on the substrate along which the passed information /prediction is acted upon by the other agents. By using the minority game for competition dynamics, here we show that when the substrate network is highly connected, the action network spontaneously develops hubs with a broad distribution of out-degrees, defining a robust leadership structure that is scale-free. Furthermore, in certain, realistic parameter ranges, facilitated by information passing on the action network, agents can spontaneously generate a high degree of cooperation making the collective almost maximally efficient.

  16. P30 Cancer Center Support Grant Administrative Supplements to support NCI Approved Clinical Trial Proposals from NCI-designated Cancer Centers not affiliated with the NCI Experimental Therapeutics Clinical Trials Network (ETCTN) for Investigator-Initiated Trials Utilizing CTEP IND agents in the ETCTN

    Cancer.gov

    P30 Cancer Center Support Grant Administrative Supplements to support NCI Approved Clinical Trial Proposals from NCI-designated Cancer Centers not affiliated with the NCI Experimental Therapeutics Clinical Trials Network (ETCTN) for Investigator-Initiated Trials Utilizing CTEP IND agents in the ETCTN

  17. Organization of complex networks

    NASA Astrophysics Data System (ADS)

    Kitsak, Maksim

    Many large complex systems can be successfully analyzed using the language of graphs and networks. Interactions between the objects in a network are treated as links connecting nodes. This approach to understanding the structure of networks is an important step toward understanding the way corresponding complex systems function. Using the tools of statistical physics, we analyze the structure of networks as they are found in complex systems such as the Internet, the World Wide Web, and numerous industrial and social networks. In the first chapter we apply the concept of self-similarity to the study of transport properties in complex networks. Self-similar or fractal networks, unlike non-fractal networks, exhibit similarity on a range of scales. We find that these fractal networks have transport properties that differ from those of non-fractal networks. In non-fractal networks, transport flows primarily through the hubs. In fractal networks, the self-similar structure requires any transport to also flow through nodes that have only a few connections. We also study, in models and in real networks, the crossover from fractal to non-fractal networks that occurs when a small number of random interactions are added by means of scaling techniques. In the second chapter we use k-core techniques to study dynamic processes in networks. The k-core of a network is the network's largest component that, within itself, exhibits all nodes with at least k connections. We use this k-core analysis to estimate the relative leadership positions of firms in the Life Science (LS) and Information and Communication Technology (ICT) sectors of industry. We study the differences in the k-core structure between the LS and the ICT sectors. We find that the lead segment (highest k-core) of the LS sector, unlike that of the ICT sector, is remarkably stable over time: once a particular firm enters the lead segment, it is likely to remain there for many years. In the third chapter we study how

  18. Health care agents

    MedlinePlus

    Durable power of attorney for health care; Health care proxy; End-of-life - health care agent; Life support treatment - ... Respirator - health care agent; Ventilator - health care agent; Power of attorney - health care agent; POA - health care ...

  19. 21 CFR 7.46 - Firm-initiated recall.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Firm-initiated recall. 7.46 Section 7.46 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL ENFORCEMENT POLICY Recalls (Including Product Corrections)-Guidance on Policy, Procedures, and Industry Responsibilities §...

  20. Knowledge Management and the Competitive Strategy of the Firm

    ERIC Educational Resources Information Center

    Halawi, Leila A.; McCarthy, Richard V.; Aronson, Jay E.

    2006-01-01

    Purpose: Knowledge management (KM) has emerged as a strategy to improve organizational competitiveness. Our purpose is to identify the relationship between KM and the firm's competitive advantage. Design/methodology/approach: We review the existing literature on KM and strategy formulation. We utilize the resource-based view approach as a lens for…