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Sample records for firm agent network

  1. Quantitative agent-based firm dynamics simulation with parameters estimated by financial and transaction data analysis

    NASA Astrophysics Data System (ADS)

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

    2007-03-01

    Firm dynamics on a transaction network is considered from the standpoint of econophysics, agent-based simulations, and game theory. In this model, interacting firms rationally invest in a production facility to maximize net present value. We estimate parameters used in the model through empirical analysis of financial and transaction data. We propose two different methods ( analytical method and regression method) to obtain an interaction matrix of firms. On a subset of a real transaction network, we simulate firm's revenue, cost, and fixed asset, which is the accumulated investment for the production facility. The simulation reproduces the quantitative behavior of past revenues and costs within a standard error when we use the interaction matrix estimated by the regression method, in which only transaction pairs are taken into account. Furthermore, the simulation qualitatively reproduces past data of fixed assets.

  2. Construction of a microscopic agent-based model for firms' dynamics

    NASA Astrophysics Data System (ADS)

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

    2005-07-01

    A workable microscopic model for firms' dynamics has been constructed. The model consists of firm agents and a bank agent dynamics of which are described by balance sheets. The size distribution of firms and the temporal evolution of the bank show critical dependence on whether or not firms use perfect information on their financial conditions to draw up next production plans.

  3. Networks of Firms and the Ridge in the Production Space

    NASA Astrophysics Data System (ADS)

    Souma, Wataru

    We develop complex networks that represent activities in the economy. The network in this study is constructed from firms and the relationships between firms, i.e., shareholding, interlocking directors, transactions, and joint applications for patents. Thus, the network is regarded as a multigraph, and it is also regarded as a weighted network. By calculating various network indices, we clarify the characteristics of the network. We also consider the dynamics of firms in the production space that are characterized by capital stock, employment, and profit. Each firm moves within this space to maximize their profit by using controlling of capital stock and employment. We show that the dynamics of rational firms can be described using a ridge equation. We analytically solve this equation by assuming the extensive Cobb-Douglas production function, and thereby obtain a solution. By comparing the distribution of firms and this solution, we find that almost all of the 1,100 firms listed on the first section of the Tokyo stock exchange and belonging to the manufacturing sector are managed efficiently.

  4. 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. PMID:25933413

  5. 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

  6. Toward Agent-Based Models of the Development And Evolution of Business Relations and Networks

    NASA Astrophysics Data System (ADS)

    Wilkinson, Ian F.; Marks, Robert E.; Young, Louise

    Firms achieve competitive advantage in part through the development of cooperative relations with other firms and organisations. We describe a program of research designed to map and model the development of cooperative inter-firm relations, including the processes and paths by which firms may evolve from adversarial to more cooperative relations. Narrative-event-history methods will be used to develop stylised histories of the emergence of business relations in various contexts and to identify relevant causal mechanisms to be included in the agent-based models of relationship and network evolution. The relationship histories will provide the means of assuring the agent-based models developed.

  7. 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.

  8. 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) Case study…

  9. Pinning synchronization of a mobile agent network

    NASA Astrophysics Data System (ADS)

    Wang, Lei; Sun, You-xian

    2009-11-01

    We investigate the problem of controlling a group of mobile agents in a plane in order to move them towards a desired orbit via pinning control, in which each agent is associated with a chaotic oscillator coupled with those of neighboring agents, and the pinning strategy is to have the common linear feedback acting on a small fraction of agents by random selection. We explore the effects of the pinning probability, feedback gains and agent density in the pinning synchronization of a mobile agent network under a fast-switching constraint, and perform numerical simulations for validation. In particular, we show that there exists a critical pinning density for network synchronization with an unbounded region: above the threshold, the dynamical network can be controlled by pinning; below it, anarchy prevails. And for the network with a single bounded synchronization region, pinning control has little effect as regards enhancing network synchronizability.

  10. An agent-based macroeconomic model with interacting firms, socio-economic opinion formation and optimistic/pessimistic sales expectations

    NASA Astrophysics Data System (ADS)

    Westerhoff, Frank

    2010-07-01

    We propose a simple agent-based macroeconomic model in which firms hold heterogeneous sales expectations. A firm may either optimistically expect an increase in its sales or pessimistically expect the opposite. Whether a given firm is optimistic or pessimistic depends on macroeconomic conditions and the average mood prevailing within its social/local neighborhood. For instance, the probability of a firm taking an optimistic view increases not only during a boom but also with the number of its optimistic neighbors. We show that such an economy may give rise to co-evolving dynamics between the business cycle and the firms' average sentiment.

  11. 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.

  12. Knowledge-Intensive University Spin-Off Firms in South Africa: Fragile Network Alignment?

    ERIC Educational Resources Information Center

    Kruss, Glenda

    2008-01-01

    This paper analyses the conditions for sustaining spin-off firms from university-based research in South Africa through follow-up case studies of three high-technology networks, using a "network alignment" approach. Commercialization failed in the first case because of a lack of interactive capability and an absence of networks between the…

  13. Transient fluctuation of the prosperity of firms in a network economy

    NASA Astrophysics Data System (ADS)

    Maeno, Yoshiharu

    2013-08-01

    The transient fluctuation of the prosperity of firms in a network economy is investigated with an abstract stochastic model. The model describes the profit which firms make when they sell materials to a firm which produces a product and the fixed cost expense to the firms to produce those materials and product. The formulas for this model are parallel to those for population dynamics. The swinging changes in the fluctuation in the transient state from the initial growth to the final steady state are the consequence of a topology-dependent time trial competition between the profitable interactions and expense. The firm in a sparse random network economy is more likely to go bankrupt than expected from the value of the limit of the fluctuation in the steady state, and there is a risk of failing to reach by far the less fluctuating steady state.

  14. 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.

  15. Agent routing algorithm in wireless sensor networks

    NASA Astrophysics Data System (ADS)

    Zhang, Yuqing; Yang, Shuqun

    2013-03-01

    Wireless sensor networks are a new technology of information acquisition and processing, so they are widely used in all kinds of fields. In the paper we introduce Agent technology into the wireless sensor network, conduct a in-depth research on the four routing schemes, and propose a new improved routing scheme, which considers the energy consumption of both nodes and path. Furthermore, The scheme we proposed has efficient routing function, can balance the energy consumption of nodes and extends the lifetime of the network in a more efficient way.

  16. Mean Field Approximation for Biased Diffusion on Japanese Inter-Firm Trading Network

    PubMed Central

    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. PMID:24626149

  17. 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. PMID:24626149

  18. Cultural Differences in an Interorganizational Network: Shared Public Relations Firms among Japanese and American Companies.

    ERIC Educational Resources Information Center

    Jang, Ha-Yong

    1997-01-01

    Investigates impact of national culture on interorganizational relationships among organizations. Matches 35 Japanese and American companies by their business types. Reveals that the network of shared public relations firms was loosely connected--American companies were more central. Indicates the network structure of shared public relations firms…

  19. 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. PMID:24730170

  20. 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

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. Economic Path Scheduling for Mobile Agent System on Computer Network

    NASA Astrophysics Data System (ADS)

    Olajubu, E. A.

    Mobile agent technology has a lot of gains to offer network-centric applications. The technology promises to be very suitable for narrow-bandwidth networks by reducing network latency and allowing transparent per-to-per computing. Multi-agent technology had been proposed for many network-centric applications with little or no path scheduling algorithms. This paper describes the need for path scheduling algorithms for agents in multi-agent systems. Traveling salesman problem (TSP) scheme is used to model ordered agents and the unordered agents schedule their path based on random distribution. The two types of agents were modeled and simulated based on bandwidth usage and response time as performance metrics. Our simulation results shows that ordered agents have superior performance against unordered agents. The ordered agents exhibit lower bandwidth usage and higher response time.

  6. 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.

  7. 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);…

  8. 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. PMID:23382916

  9. 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

  10. 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. PMID:20365825

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

    NASA Astrophysics Data System (ADS)

    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 λ increases, and disappear for λ≥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.

  12. 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.

  13. Model of mobile agents for sexual interactions networks

    NASA Astrophysics Data System (ADS)

    González, M. C.; Lind, P. G.; Herrmann, H. J.

    2006-02-01

    We present a novel model to simulate real social networks of complex interactions, based in a system of colliding particles (agents). The network is build by keeping track of the collisions and evolves in time with correlations which emerge due to the mobility of the agents. Therefore, statistical features are a consequence only of local collisions among its individual agents. Agent dynamics is realized by an event-driven algorithm of collisions where energy is gained as opposed to physical systems which have dissipation. The model reproduces empirical data from networks of sexual interactions, not previously obtained with other approaches.

  14. 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…

  15. Self-organized networks of competing boolean agents

    PubMed

    Paczuski; Bassler; Corral

    2000-04-01

    A model of Boolean agents competing in a market is presented where each agent bases his action on information obtained from a small group of other agents. The agents play a competitive game that rewards those in the minority. After a long time interval, the poorest player's strategy is changed randomly, and the process is repeated. Eventually the network evolves to a stationary but intermittent state where random mutation of the worst strategy can change the behavior of the entire network, often causing a switch in the dynamics between attractors of vastly different lengths. PMID:11019043

  16. 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

  17. 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.

  18. 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.

  19. 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

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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…

  7. 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.

  8. 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

  9. 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. PMID:22303172

  10. 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.

  11. Agents in Safety Related Systems Including Ubiquitous Networks

    NASA Astrophysics Data System (ADS)

    Strandén, Lars

    The ADM (Autonomous Decision Maker) concept concerns the possibility of including intelligent interfaces, agent like, for supporting the use of ubiquitous networks, such as the Internet, in safety related applications. The need for such interfaces is inevitable if remote surveillance and control shall be supported. The single most important aspect of ADM is its capability of handling limited resources when making intelligent decisions. Intelligence in ADM is manifested in reasoning and learning. This paper outlines the role of ADM and especially in relation to the standard IEC 61508 and presents the overall properties that result. These are exemplified by a presentation of ADM demonstrator.

  12. 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.

  13. Topology for Dominance for Network of Multi-Agent System

    NASA Astrophysics Data System (ADS)

    Szeto, K. Y.

    2007-05-01

    The resource allocation problem in evolving two-dimensional point patterns is investigated for the existence of good strategies for the construction of initial configuration that leads to fast dominance of the pattern by one single species, which can be interpreted as market dominance by a company in the context of multi-agent systems in econophysics. For hexagonal lattice, certain special topological arrangements of the resource in two-dimensions, such as rings, lines and clusters have higher probability of dominance, compared to random pattern. For more complex networks, a systematic way to search for a stable and dominant strategy of resource allocation in the changing environment is found by means of genetic algorithm. Five typical features can be summarized by means of the distribution function for the local neighborhood of friends and enemies as well as the local clustering coefficients: (1) The winner has more triangles than the loser has. (2) The winner likes to form clusters as the winner tends to connect with other winner rather than with losers; while the loser tends to connect with winners rather than losers. (3) The distribution function of friends as well as enemies for the winner is broader than the corresponding distribution function for the loser. (4) The connectivity at which the peak of the distribution of friends for the winner occurs is larger than that of the loser; while the peak values for friends for winners is lower. (5) The connectivity at which the peak of the distribution of enemies for the winner occurs is smaller than that of the loser; while the peak values for enemies for winners is lower. These five features appear to be general, at least in the context of two-dimensional hexagonal lattices of various sizes, hierarchical lattice, Voronoi diagrams, as well as high-dimensional random networks. These general local topological properties of networks are relevant to strategists aiming at dominance in evolving patterns when the

  14. Study and implementation of the network management agent of telecommunication application server in NGN

    NASA Astrophysics Data System (ADS)

    Liu, Kun; He, Hui; Ni, Yuhua

    2013-03-01

    The telecommunication application server (AS) is an important part of the value-added service network in the next generation network(NGN) as the support platform. Remote, unified and secure management to a variety of services is implemented after the remote network management of the telecommunications application server. The network management system based on Simple Network Management Protocol (SNMP) is decided to utilized to analyse and study the network managed objects in AS because of the integration of telecommunications networks and computer networks on the network management and convenient, economical and flexible features of SNMP protocol. The network management agent module of AS is designed and an example is illustrated the details of the model. Results indicate the good performance of the network management agent.

  15. 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.

  16. Design of AgentX in SNMP-based SDH management network

    NASA Astrophysics Data System (ADS)

    Liang, Xiaohong; Sun, Minghai; Feng, ChongXi

    2002-09-01

    Management network plays an important role in the SDH transport system. Adopting the management architecture of CMIP, traditional SDH management network is chiefly a subset of TMN. Although its management ability is powerful, it is complex to implement. Considering not only the SNMP's simplicity and low resource consumption but also the flexible extensibility brought by the application of the extensible agent (AgentX) architecture, a different strategy of the SDH management network based on the SNMP management structure with AgentX is proposed in this paper. The design scheme of AgentX in the system is discussed further.

  17. 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.

  18. Multi-Agent Framework in Visual Sensor Networks

    NASA Astrophysics Data System (ADS)

    Patricio, M. A.; Carbó, J.; Pérez, O.; García, J.; Molina, J. M.

    2006-12-01

    The recent interest in the surveillance of public, military, and commercial scenarios is increasing the need to develop and deploy intelligent and/or automated distributed visual surveillance systems. Many applications based on distributed resources use the so-called software agent technology. In this paper, a multi-agent framework is applied to coordinate videocamera-based surveillance. The ability to coordinate agents improves the global image and task distribution efficiency. In our proposal, a software agent is embedded in each camera and controls the capture parameters. Then coordination is based on the exchange of high-level messages among agents. Agents use an internal symbolic model to interpret the current situation from the messages from all other agents to improve global coordination.

  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. 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. PMID:23605144

  1. Consensus of networked multi-agent systems with communication delays based on the networked predictive control scheme

    NASA Astrophysics Data System (ADS)

    Tan, Chong; Liu, Guo-Ping; Duan, Guang-Ren

    2012-07-01

    The consensus problem of discrete-time networked multi-agent systems (NMASs) with a communication delay is investigated in this article, where the dynamics of agents described by discrete-time linear time-invariant systems can be either uniform or non-uniform. For the NMASs with a directed topology and constant delay, a novel protocol based on the networked predictive control scheme is proposed to compensate for communication delay actively. Using algebraic graph theories and matrix theories, necessary and/or sufficient conditions of achieving consensus are obtained, which indicates that, under the proposed protocol, the consensus is independent of the network delay and only dominated by agents' dynamics and communication topology. Meanwhile, the protocol design and consensus analysis are also presented in the case of no network delay. Simulation results are further presented to demonstrate the effectiveness of theoretical results.

  2. 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.

  3. Multi-agent systems and neural networks for automatic target recognition on air images

    NASA Astrophysics Data System (ADS)

    Cozien, Roger F.; Rosenberger, Christophe; Eyherabide, Partrick; Rossettini, Joaquim; Ceyrolle, Arnaud

    2000-08-01

    Our purpose is, in medium term, to detect in air images, characteristic shapes and objects such as airports, industrial plants, planes, tanks, trucks, ... with great accuracy and low rate of mistakes. However, we also want to value whether the link between neural networks and multi-agents systems is relevant and effective. If it appears to be really effective, we hope to use this kind of technology in other fields. That would be an easy and convenient way to depict and to use the agents' knowledge which is distributed and fragmented. After a first phase of preliminary tests to know if agents are able to give relevant information to a neural network, we verify that only a few agents running on an image are enough to inform the network and let it generalize the agents' distributed and fragmented knowledge. In a second phase, we developed a distributed architecture allowing several multi- agents systems running at the same time on different computers with different images. All those agents send information to a 'multi neural networks system' whose job is to identify the shapes detected by the agents. The name we gave to our project is Jarod.

  4. 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.

  5. 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…

  6. Knowledge acquisition by networks of interacting agents in the presence of observation errors

    NASA Astrophysics Data System (ADS)

    Batista, J. B.; Costa, L. Da F.

    2010-07-01

    In this work we investigate knowledge acquisition as performed by multiple agents interacting as they infer, under the presence of observation errors, respective models of a complex system. We focus the specific case in which, at each time step, each agent takes into account its current observation as well as the average of the models of its neighbors. The agents are connected by a network of interaction of Erdős-Rényi or Barabási-Albert type. First, we investigate situations in which one of the agents has a different probability of observation error (higher or lower). It is shown that the influence of this special agent over the quality of the models inferred by the rest of the network can be substantial, varying linearly with the respective degree of the agent with different estimation error. In case the degree of this agent is taken as a respective fitness parameter, the effect of the different estimation error is even more pronounced, becoming superlinear. To complement our analysis, we provide the analytical solution of the overall performance of the system. We also investigate the knowledge acquisition dynamic when the agents are grouped into communities. We verify that the inclusion of edges between agents (within a community) having higher probability of observation error promotes the loss of quality in the estimation of the agents in the other communities.

  7. Impulsive consensus seeking in directed networks of multi-agent systems with communication time delays

    NASA Astrophysics Data System (ADS)

    Wu, Quanjun; Zhou, Jin; Xiang, Lan

    2012-08-01

    In this article, we consider average consensus problem in directed delayed networked multi-agent systems having impulsive effects with fixed topology and stochastic switching topology. A simple impulsive consensus protocol for such networks is proposed, and some generic criteria for solving the average consensus problem are analytically derived. It is shown that a directed delayed networked multi-agent system can achieve average consensus globally exponentially with suitable impulsive gain and impulsive interval. Subsequently, two typical illustrative examples, along with computer simulation results, are provided to visualise the effectiveness and feasibility of our theoretical results.

  8. 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. PMID:25683347

  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. Rigidity based formation tracking for multi-agent networks

    NASA Astrophysics Data System (ADS)

    Bai, Lu; Chen, Fei; Lan, Wei-Yao

    2015-09-01

    This paper considers the formation tracking problem under a rigidity framework, where the target formation is specified as a minimally and infinitesimally rigid formation and the desired velocity of the group is available to only a subset of the agents. The following two cases are considered: the desired velocity is constant, and the desired velocity is time-varying. In the first case, a distributed linear estimator is constructed for each agent to estimate the desired velocity. The velocity estimation and a formation acquisition term are employed to design the control inputs for the agents, where the rigidity matrix plays a central role. In the second case, a distributed non-smooth estimator is constructed to estimate the time-varying velocity, which is shown to converge in a finite time. Theoretical analysis shows that the formation tracking problem can be solved under the proposed control algorithms and estimators. Simulation results are also provided to show the validity of the derived results. Project supported by the National Natural Science Foundation of China (Grant No. 61473240).

  11. The multi-agent Parrondo’s model based on the network evolution

    NASA Astrophysics Data System (ADS)

    Ye, Ye; Xie, Neng-gang; Wang, Lu; Cen, Yu-wan

    2013-11-01

    A multi-agent Parrondo’s model is proposed in the paper. The model includes link A based on the rewiring mechanism (the network evolution) + game B (dependent on the spatial neighbors). Moreover, to produce the paradoxical effect and analyze the “agitating” effect of the network evolution, the dynamic processes of the network evolution + game B are studied. The simulation results and the theoretical analysis both show that the network evolution can make game B which is losing produce the winning paradoxical effect. Furthermore, we obtain the parameter space where the strong or weak Parrondo’s paradox occurs. Each size of the region of the parameter space is larger than the one in the available multi-agent Parrondo’s model of game A + game B. This result shows that the “agitating” effect of rewiring based on the network evolution is better than that of the zero-sum game between individuals.

  12. 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.

  13. 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

  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. A new protocol for finite-time consensus of detail-balanced multi-agent networks.

    PubMed

    Yang, Shaofu; Cao, Jinde; Lu, Jianquan

    2012-12-01

    In this paper, a finite-time consensus protocol for multi-agent networks is discussed from a new perspective. The order β of the nonlinear function in the protocol is shown to be a crucial parameter in analyzing the finite-time consensus property of multi-agent networks with a detail-balanced communication topology. When β>0, the corresponding protocol can guarantee the consensus of the multi-agent networks. In particular, if β∈(0,1), the consensus can be realized within finite time. A leader-follow model is also investigated in this paper. Finally, several concrete protocols are proposed based on our theoretical analysis, and numerical examples are given to make a comparison among different protocols from the aspect of convergence speed. PMID:23278069

  17. 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.

  18. 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.

  19. 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.

  20. Joining consensus of networked multi-agent systems with nonlinear couplings and weighting constraints

    NASA Astrophysics Data System (ADS)

    Wang, Bohui; Wang, Jingcheng; Zhang, Langwen; Ge, Yang

    2016-04-01

    This paper studies the joining consensus of networked multi-agent systems subject to nonlinear couplings and weighted directed graphs via pinning control. A weighted-average consensus protocol is proposed to achieve the collective decision by interacting with the local information of some pinned agents. By proposing a novel joining consensus protocol, average consensus and general consensus strategies are joined to achieve an agreement for the weighting networked system. Furthermore, by calculating a proper consensus gain and using finite control Lyapunov controllers, an efficient joining consensus protocol is presented to improve the consensus speed. Sufficient conditions for achieving the consensuses asymptotically are proved. Finally, theoretical results are validated via simulations.

  1. 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.

  2. 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.

  3. 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

  4. 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

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. Amphiphilic Interpenetrating Networks for the Delivery of Hydrophobic, Low Molecular Weight Therapeutic Agents

    PubMed Central

    Schoener, Cody A.; Hutson, Heather N.; Fletcher, Grace K.; Peppas, Nicholas A.

    2011-01-01

    To investigate the delivery of hydrophobic therapeutic agents, a novel class of interpenetrating networks (IPNs) were synthesized and composed of two networks: methacrylic acid grafted with poly(ethylene glycol) tethers, P(MAA-g-EG), and poly(n-butyl acrylate) (PBA). The hydrophilic P(MAA-g-EG) networks are pH-responsive hydrogels capable of triggered release of an encapsulated therapeutic agent, such as a low molecular weight drug or a protein, when it passes from the stomach (low pH) to upper small intestine (neutral pH). PBA is a hydrophobic homopolymer that can affect the IPN swelling behavior, the therapeutic agent loading efficiencies in IPNs, and solute release profiles from IPNs. In dynamic swelling conditions, IPNs had greater swelling ratios than P(MAA-g-EG), but in equilibrium swelling conditions the IPN swelling ratio decreased with increasing PBA content. Loading efficiencies of the model therapeutic agent fluorescein ranged from 21 – 44%. Release studies from neat P(MAA-g-EG) and the ensuing IPNs indicated that the transition from low pH (2.0) to neutral pH (7.0) triggered fluorescein release. Maximum fluorescein release depended on the structure and hydrophilicity of the carriers used in these studies. PMID:22247592

  12. 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

  13. A new HIV prevention network approach: sociometric peer change agent selection.

    PubMed

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

    2015-01-01

    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

  14. 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.

  15. 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.

  16. Collective Motion in a Network of Self-Propelled Agent Systems.

    PubMed

    Peng, Hao; Zhao, Dandan; Liu, Xueming; Gao, Jianxi

    2015-01-01

    Collective motions of animals that move towards the same direction is a conspicuous feature in nature. Such groups of animals are called a self-propelled agent (SPA) systems. Many studies have been focused on the synchronization of isolated SPA systems. In real scenarios, different SPA systems are coupled with each other forming a network of SPA systems. For example, a flock of birds and a school of fish show predator-prey relationships and different groups of birds may compete for food. In this work, we propose a general framework to study the collective motion of coupled self-propelled agent systems. Especially, we study how three different connections between SPA systems: symbiosis, predator-prey, and competition influence the synchronization of the network of SPA systems. We find that a network of SPA systems coupled with symbiosis relationship arrive at a complete synchronization as all its subsystems showing a complete synchronization; a network of SPA systems coupled by predator-prey relationship can not reach a complete synchronization and its subsystems converges to different synchronized directions; and the competitive relationship between SPA systems could increase the synchronization of each SPA systems, while the network of SPA systems coupled by competitive relationships shows an optimal synchronization for small coupling strength, indicating that small competition promotes the synchronization of the entire system. PMID:26640954

  17. Collective Motion in a Network of Self-Propelled Agent Systems

    PubMed Central

    Peng, Hao; Zhao, Dandan; Liu, Xueming; Gao, Jianxi

    2015-01-01

    Collective motions of animals that move towards the same direction is a conspicuous feature in nature. Such groups of animals are called a self-propelled agent (SPA) systems. Many studies have been focused on the synchronization of isolated SPA systems. In real scenarios, different SPA systems are coupled with each other forming a network of SPA systems. For example, a flock of birds and a school of fish show predator-prey relationships and different groups of birds may compete for food. In this work, we propose a general framework to study the collective motion of coupled self-propelled agent systems. Especially, we study how three different connections between SPA systems: symbiosis, predator-prey, and competition influence the synchronization of the network of SPA systems. We find that a network of SPA systems coupled with symbiosis relationship arrive at a complete synchronization as all its subsystems showing a complete synchronization; a network of SPA systems coupled by predator-prey relationship can not reach a complete synchronization and its subsystems converges to different synchronized directions; and the competitive relationship between SPA systems could increase the synchronization of each SPA systems, while the network of SPA systems coupled by competitive relationships shows an optimal synchronization for small coupling strength, indicating that small competition promotes the synchronization of the entire system. PMID:26640954

  18. Dynamics of bloggers’ communities: Bipartite networks from empirical data and agent-based modeling

    NASA Astrophysics Data System (ADS)

    Mitrović, Marija; Tadić, Bosiljka

    2012-11-01

    We present an analysis of the empirical data and the agent-based modeling of the emotional behavior of users on the Web portals where the user interaction is mediated by posted comments, like Blogs and Diggs. We consider the dataset of discussion-driven popular Diggs, in which all comments are screened by machine-learning emotion detection in the text, to determine positive and negative valence (attractiveness and aversiveness) of each comment. By mapping the data onto a suitable bipartite network, we perform an analysis of the network topology and the related time-series of the emotional comments. The agent-based model is then introduced to simulate the dynamics and to capture the emergence of the emotional behaviors and communities. The agents are linked to posts on a bipartite network, whose structure evolves through their actions on the posts. The emotional states (arousal and valence) of each agent fluctuate in time, subject to the current contents of the posts to which the agent is exposed. By an agent’s action on a post its current emotions are transferred to the post. The model rules and the key parameters are inferred from the considered empirical data to ensure their realistic values and mutual consistency. The model assumes that the emotional arousal over posts drives the agent’s action. The simulations are preformed for the case of constant flux of agents and the results are analyzed in full analogy with the empirical data. The main conclusions are that the emotion-driven dynamics leads to long-range temporal correlations and emergent networks with community structure, that are comparable with the ones in the empirical system of popular posts. In view of pure emotion-driven agents actions, this type of comparisons provide a quantitative measure for the role of emotions in the dynamics on real blogs. Furthermore, the model reveals the underlying mechanisms which relate the post popularity with the emotion dynamics and the prevalence of negative

  19. 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

  20. Memory Transmission in Small Groups and Large Networks: An Agent-Based Model.

    PubMed

    Luhmann, Christian C; Rajaram, Suparna

    2015-12-01

    The spread of social influence in large social networks has long been an interest of social scientists. In the domain of memory, collaborative memory experiments have illuminated cognitive mechanisms that allow information to be transmitted between interacting individuals, but these experiments have focused on small-scale social contexts. In the current study, we took a computational approach, circumventing the practical constraints of laboratory paradigms and providing novel results at scales unreachable by laboratory methodologies. Our model embodied theoretical knowledge derived from small-group experiments and replicated foundational results regarding collaborative inhibition and memory convergence in small groups. Ultimately, we investigated large-scale, realistic social networks and found that agents are influenced by the agents with which they interact, but we also found that agents are influenced by nonneighbors (i.e., the neighbors of their neighbors). The similarity between these results and the reports of behavioral transmission in large networks offers a major theoretical insight by linking behavioral transmission to the spread of information. PMID:26553014

  1. Pervasive surveillance-agent system based on wireless sensor networks: design and deployment

    NASA Astrophysics Data System (ADS)

    Martínez, José F.; Bravo, Sury; García, Ana B.; Corredor, Iván; Familiar, Miguel S.; López, Lourdes; Hernández, Vicente; Da Silva, Antonio

    2010-12-01

    Nowadays, proliferation of embedded systems is enhancing the possibilities of gathering information by using wireless sensor networks (WSNs). Flexibility and ease of installation make these kinds of pervasive networks suitable for security and surveillance environments. Moreover, the risk for humans to be exposed to these functions is minimized when using these networks. In this paper, a virtual perimeter surveillance agent, which has been designed to detect any person crossing an invisible barrier around a marked perimeter and send an alarm notification to the security staff, is presented. This agent works in a state of 'low power consumption' until there is a crossing on the perimeter. In our approach, the 'intelligence' of the agent has been distributed by using mobile nodes in order to discern the cause of the event of presence. This feature contributes to saving both processing resources and power consumption since the required code that detects presence is the only system installed. The research work described in this paper illustrates our experience in the development of a surveillance system using WNSs for a practical application as well as its evaluation in real-world deployments. This mechanism plays an important role in providing confidence in ensuring safety to our environment.

  2. 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.

  3. Transcriptional response networks for elucidating mechanisms of action of multitargeted agents.

    PubMed

    Kibble, Milla; Khan, Suleiman A; Saarinen, Niina; Iorio, Francesco; Saez-Rodriguez, Julio; Mäkelä, Sari; Aittokallio, Tero

    2016-07-01

    Drug discovery is moving away from the single target-based approach towards harnessing the potential of polypharmacological agents that modulate the activity of multiple nodes in the complex networks of deregulations underlying disease phenotypes. Computational network pharmacology methods that use systems-level drug-response phenotypes, such as those originating from genome-wide transcriptomic profiles, have proved particularly effective for elucidating the mechanisms of action of multitargeted compounds. Here, we show, via the case study of the natural product pinosylvin, how the combination of two complementary network-based methods can provide novel, unexpected mechanistic insights. This case study also illustrates that elucidating the mechanism of action of multitargeted natural products through transcriptional response-based approaches is a challenging endeavor, often requiring multiple computational-experimental iterations. PMID:26979547

  4. 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

  5. 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.

  6. Coevolutionary, coexisting learning and teaching agents model for prisoner’s dilemma games enhancing cooperation with assortative heterogeneous networks

    NASA Astrophysics Data System (ADS)

    Tanimoto, Jun

    2013-07-01

    Unlike other natural network systems, assortativity can be observed in most human social networks, although it has been reported that a social dilemma situation represented by the prisoner’s dilemma favors dissortativity to enhance cooperation. We established a new coevolutionary model for both agents’ strategy and network topology, where teaching and learning agents coexist. Remarkably, this model enables agents’ enhancing cooperation more than a learners-only model on a time-frozen scale-free network and produces an underlying assortative network with a fair degree of power-law distribution. The model may imply how and why assortative networks are adaptive in human society.

  7. On The Wealth Distribution Of A Simulated Kinetic Economy With An Arbitrary Fraction of Agents Networking Trading Opportunities

    NASA Astrophysics Data System (ADS)

    Khidzir, Sidiq Mohamad; Abdullah, Wan Ahmad Tajuddin Wan

    2008-05-01

    We study a trading model where agents trade money based on an arbitrary random fractions similar to works done by Chakraborti and Chatterjee, arXiv:0710.0917, but embed a networking capability to an arbitrary percentage of agents. We do this to see the effects on the power law in the wealth distribution. Our studies show that the percentage of networking affects the value of the Pareto Exponent.

  8. 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. PMID:27061152

  9. Consensus tracking of linear multi-agent systems under networked observability conditions

    NASA Astrophysics Data System (ADS)

    Diao, Miao; Duan, Zhisheng; Wen, Guanghui

    2014-08-01

    This paper addresses the consensus tracking problem for both continuous- and discrete-time linear multi-agent systems with a dynamic leader under networked observability conditions. Among followers, the communication topology is assumed to be undirected and connected. Two networked observability conditions are introduced and discussed. The first one extends the traditional detectability condition for a single system, while the second one is a full rank condition, which is stronger than the first one. In the continuous-time case, two distributed observer-based protocols are designed under corresponding networked observability conditions, respectively. Specifically, the second protocol is an adaptive one, which has a better robustness performance than the first one. In the discrete-time case, a distributed observer-based protocol is presented under the full rank networked observability condition. It is found that under the networked observability conditions, consensus tracking can still be achieved even if there exists no follower being able to track the leader independently. Based on algebraic graph theory and Lyapunov stability theory, some sufficient conditions are derived for reaching consensus tracking. Finally, simulation examples are presented to verify the effectiveness of theoretical results.

  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. PMID:22327550

  12. 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.

  13. 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.

  14. 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

  15. 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

  16. Employment growth through labor flow networks.

    PubMed

    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

  17. 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

  18. The co-evolutionary dynamics of directed network of spin market agents

    NASA Astrophysics Data System (ADS)

    Horváth, Denis; Kuscsik, Zoltán; Gmitra, Martin

    2006-09-01

    The spin market model [S. Bornholdt, Int. J. Mod. Phys. C 12 (2001) 667] is generalized by employing co-evolutionary principles, where strategies of the interacting and competitive traders are represented by local and global couplings between the nodes of dynamic directed stochastic network. The co-evolutionary principles are applied in the frame of Bak-Sneppen self-organized dynamics [P. Bak, K. Sneppen, Phys. Rev. Lett. 71 (1993) 4083] that includes the processes of selection and extinction actuated by the local (node) fitness. The local fitness is related to orientation of spin agent with respect to the instant magnetization. The stationary regime is formed due to the interplay of self-organization and adaptivity effects. The fat tailed distributions of log-price returns are identified numerically. The non-trivial model consequence is the evidence of the long time market memory indicated by the power-law range of the autocorrelation function of volatility with exponent smaller than one. The simulations yield network topology with broad-scale node degree distribution characterized by the range of exponents 1.3<γin<3 coinciding with social networks.

  19. A Unified Multiscale Field/Network/Agent Based Modeling Framework for Human and Ecological Health Risk Analysis

    PubMed Central

    Georgopoulos, Panos G.; Isukapalli, Sastry S.

    2011-01-01

    A conceptual framework is presented for multiscale field/network/agent-based modeling to support human and ecological health risk assessments. This framework is based on the representation of environmental dynamics in terms of interacting networks, agents that move across different networks, fields representing spatiotemporal distributions of physical properties, rules governing constraints and interactions, and actors that make decisions affecting the state of the system. Different deterministic and stochastic modeling case studies focusing on environmental exposures and associated risks are provided as examples, utilizing the bidirectional mapping between discrete, agent based approaches and continuous, equation based approaches. These examples include problems describing human health risk assessment, ecological risk assessment, and environmentally caused disease. PMID:19964423

  20. 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.

  1. 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. PMID:26158406

  2. 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.

  3. 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.

  4. 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

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

    PubMed

    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

    2016-03-01

    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

  6. Distributed coordination of heterogeneous agents using a semantic overlay network and a goal-directed graphplan planner.

    PubMed

    Lopes, António Luís; Botelho, Luís Miguel

    2013-01-01

    In this paper, we describe a distributed coordination system that allows agents to seamlessly cooperate in problem solving by partially contributing to a problem solution and delegating the subproblems for which they do not have the required skills or knowledge to appropriate agents. The coordination mechanism relies on a dynamically built semantic overlay network that allows the agents to efficiently locate, even in very large unstructured networks, the necessary skills for a specific problem. Each agent performs partial contributions to the problem solution using a new distributed goal-directed version of the Graphplan algorithm. This new goal-directed version of the original Graphplan algorithm provides an efficient solution to the problem of "distraction", which most forward-chaining algorithms suffer from. We also discuss a set of heuristics to be used in the backward-search process of the planning algorithm in order to distribute this process amongst idle agents in an attempt to find a solution in less time. The evaluation results show that our approach is effective in building a scalable and efficient agent society capable of solving complex distributable problems. PMID:23704885

  7. Efficacy of a root conditioning agent on fibrin network formation in periodontal regeneration: A SEM evaluation

    PubMed Central

    Amireddy, Rajender; Rangarao, Suresh; lavu, Vamsi; Madapusi, Balaji Todur

    2011-01-01

    Background: Even though numerous biomaterials have been devised and employed for periodontal regeneration, it should be well understood that the root surface receptiveness to clot formation and maintenance during initial periodontal wound healing, decides the nature of the connective tissue attachment. So this study was carried out with the prime objective of assessing the initial wound healing events occurring in vivo after the application of citric acid on to the root surfaces during periodontal regenerative therapy. Materials and Methods: Thirty-two human teeth were used for this in vitro study. Two dentin blocks each measuring 4 × 2 × 1 mm were made from each tooth. These dentin blocks were planed and treated differently with Phosphate Buffered Saline (PBS), citric acid, PBS and fresh human blood, citric acid and fresh human blood and were segregated into eight groups. Finally all the dentin blocks were processed and subjected to a scanning electron microscope study. Results: In PBS-treated samples, the dentin surface was irregular corresponding to smear layer and the dentinal tubule openings were obscured. Whereas, in those treated with citric acid revealed a smooth dentin surface devoid of smear layer and the dentinal tubular openings were clear. Further samples that were treated with PBS plus blood showed little or no fibrin network formation whereas with those citric acid plus blood showed a fine thick fibrin network formation adhered to dentinal surface. Conclusion: The results of this present in vitro study suggests that use of citric acid as a root conditioning agent has a beneficial effect on initial wound healing events, which are critical for periodontal regenerative therapies. PMID:22028509

  8. 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

  9. 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

  10. 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

  11. 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

  12. 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. PMID:25365660

  13. 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

  14. Reducing interferences in wireless communication systems by mobile agents with recurrent neural networks-based adaptive channel equalization

    NASA Astrophysics Data System (ADS)

    Beritelli, Francesco; Capizzi, Giacomo; Lo Sciuto, Grazia; Napoli, Christian; Tramontana, Emiliano; Woźniak, Marcin

    2015-09-01

    Solving channel equalization problem in communication systems is based on adaptive filtering algorithms. Today, Mobile Agents (MAs) with Recurrent Neural Networks (RNNs) can be also adopted for effective interference reduction in modern wireless communication systems (WCSs). In this paper MAs with RNNs are proposed as novel computing algorithms for reducing interferences in WCSs performing an adaptive channel equalization. The method to provide it is so called MAs-RNNs. We perform the implementation of this new paradigm for interferences reduction. Simulations results and evaluations demonstrates the effectiveness of this approach and as better transmission performance in wireless communication network can be achieved by using the MAs-RNNs based adaptive filtering algorithm.

  15. Reaching a consensus in networks of high-order integral agents under switching directed topologies

    NASA Astrophysics Data System (ADS)

    Cheng, Long; Wang, Hanlei; Hou, Zeng-Guang; Tan, Min

    2016-06-01

    Consensus problem of high-order integral multi-agent systems under switching directed topology is considered in this study. Depending on whether the agent's full state is available or not, two distributed protocols are proposed to ensure that states of all agents can be convergent to a same stationary value. In the proposed protocols, the gain vector associated with the agent's (estimated) state and the gain vector associated with the relative (estimated) states between agents are designed in a sophisticated way. By this particular design, the high-order integral multi-agent system can be transformed into a first-order integral multi-agent system. Also, the convergence of the transformed first-order integral agent's state indicates the convergence of the original high-order integral agent's state, if and only if all roots of the polynomial, whose coefficients are the entries of the gain vector associated with the relative (estimated) states between agents, are in the open left-half complex plane. Therefore, many analysis techniques in the first-order integral multi-agent system can be directly borrowed to solve the problems in the high-order integral multi-agent system. Due to this property, it is proved that to reach a consensus, the switching directed topology of multi-agent system is only required to be 'uniformly jointly quasi-strongly connected', which seems the mildest connectivity condition in the literature. In addition, the consensus problem of discrete-time high-order integral multi-agent systems is studied. The corresponding consensus protocol and performance analysis are presented. Finally, three simulation examples are provided to show the effectiveness of the proposed approach.

  16. 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.

  17. 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

  18. 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

  19. Thermodynamics of firms' growth.

    PubMed

    Zambrano, Eduardo; Hernando, Alberto; Fernández Bariviera, Aurelio; Hernando, Ricardo; Plastino, Angelo

    2015-11-01

    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

  20. 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.

  1. 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.

  2. 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.

  3. 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…

  4. 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. PMID:25851082

  5. 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…

  6. 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…

  7. 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.

  8. 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.

  9. 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.

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

    DOE PAGESBeta

    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 plansmore » in terms of average delay, number of stops, and vehicular emissions at the network level.« less

  11. Unified web-based network management based on distributed object orientated software agents

    NASA Astrophysics Data System (ADS)

    Djalalian, Amir; Mukhtar, Rami; Zukerman, Moshe

    2002-09-01

    This paper presents an architecture that provides a unified web interface to managed network devices that support CORBA, OSI or Internet-based network management protocols. A client gains access to managed devices through a web browser, which is used to issue management operations and receive event notifications. The proposed architecture is compatible with both the OSI Management reference Model and CORBA. The steps required for designing the building blocks of such architecture are identified.

  12. 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

  13. 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…

  14. A spiking neural network model of an actor-critic learning agent.

    PubMed

    Potjans, Wiebke; Morrison, Abigail; Diesmann, Markus

    2009-02-01

    The ability to adapt behavior to maximize reward as a result of interactions with the environment is crucial for the survival of any higher organism. In the framework of reinforcement learning, temporal-difference learning algorithms provide an effective strategy for such goal-directed adaptation, but it is unclear to what extent these algorithms are compatible with neural computation. In this article, we present a spiking neural network model that implements actor-critic temporal-difference learning by combining local plasticity rules with a global reward signal. The network is capable of solving a nontrivial gridworld task with sparse rewards. We derive a quantitative mapping of plasticity parameters and synaptic weights to the corresponding variables in the standard algorithmic formulation and demonstrate that the network learns with a similar speed to its discrete time counterpart and attains the same equilibrium performance. PMID:19196231

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

    PubMed

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

    2016-08-15

    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

  16. 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

  17. 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.

  18. 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.

  19. 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

    2016-07-01

    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.

  20. 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…

  1. 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…

  2. 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. PMID:25349995

  3. 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

  4. Dynamic Agent Classification and Tracking Using an Ad Hoc Mobile Acoustic Sensor Network

    NASA Astrophysics Data System (ADS)

    Friedlander, David; Griffin, Christopher; Jacobson, Noah; Phoha, Shashi; Brooks, Richard R.

    2003-12-01

    Autonomous networks of sensor platforms can be designed to interact in dynamic and noisy environments to determine the occurrence of specified transient events that define the dynamic process of interest. For example, a sensor network may be used for battlefield surveillance with the purpose of detecting, identifying, and tracking enemy activity. When the number of nodes is large, human oversight and control of low-level operations is not feasible. Coordination and self-organization of multiple autonomous nodes is necessary to maintain connectivity and sensor coverage and to combine information for better understanding the dynamics of the environment. Resource conservation requires adaptive clustering in the vicinity of the event. This paper presents methods for dynamic distributed signal processing using an ad hoc mobile network of microsensors to detect, identify, and track targets in noisy environments. They seamlessly integrate data from fixed and mobile platforms and dynamically organize platforms into clusters to process local data along the trajectory of the targets. Local analysis of sensor data is used to determine a set of target attribute values and classify the target. Sensor data from a field test in the Marine base at Twentynine Palms, Calif, was analyzed using the techniques described in this paper. The results were compared to "ground truth" data obtained from GPS receivers on the vehicles.

  5. 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. PMID:26856461

  6. 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. PMID:23200084

  7. 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.

  8. Case study on the use of agent technology for the management of networked multimedia systems

    NASA Astrophysics Data System (ADS)

    Viana, Paula; Alves, Artu P.

    2000-10-01

    The evolution of Television towards the digital domain is opening new opportunities but also new challenges both to users and system managers. Audiovisual television archives will be an essential component of the whole digital television operators systems, as archived information needs to be available to a wide range of users. This paper presents the work developed at INESC Porto within the VIDION project and the experiments on merging television, computer and telecommunications concepts and technologies by the use of software agents and CORBA to assist in solving problems of information and system configuration and management in a TV archive. Aspects such as definition of the problem, architecture proposed and current state of the work will be the focus of the paper.

  9. 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. PMID:19169835

  10. Symmetry breaking as a model for emergent structure of heterogeneous networked robotic agents

    NASA Astrophysics Data System (ADS)

    McKee, Gerard T.; Schenker, Paul S.

    1997-09-01

    This paper explores the design of robot systems to take advantage of non-linear dynamic systems models, specifically symmetry breaking phenomena, to self-organize in response to task and environment demands. Recent research in the design of robotics systems has stressed modular, adaptable systems operating under decentralized and distributed control architectures. Cooperative and emergent behavioral structures can be built on these modules by exploiting various forms of communication and negotiation strategies. We focus on the design of individual modules and their cooperative interaction. We draw on nonlinear dynamic system models of human and animal behavior to motivate issues in the design of robot modules and systems. Sonar sensing systems comprising a ring of sonar sensors are used to illustrate the ideas within a networked robotics context, where distributed sensing modules located on multiple robots can interact cooperatively to scan an environment.

  11. 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. PMID:26819592

  12. 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

  13. 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). PMID:23663959

  14. 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.

  15. Efficacy and Safety of HER2-Targeted Agents for Breast Cancer with HER2-Overexpression: A Network Meta-Analysis

    PubMed Central

    Yu, Qiuyan; Zhu, Zhenli; Liu, Yan; Zhang, Jun; Li, Ke

    2015-01-01

    Background Clinical trials of human epidermal growth factor receptor 2 (HER2)-targeted agents added to standard treatment have been efficacious for HER2-positive (HER2+) advanced breast cancer. To our knowledge, no meta-analysis has evaluated HER2-targeted therapy including trastuzumab emtansine (T-DM1) and pertuzumab for HER2-positive breast caner and ranked the targeted treatments. We performed a network meta-analysis of both direct and indirect comparisons to evaluate the effect of adding HER2-targeted agents to standard treatment and examined side effects. Methods We performed a Bayesian-framework network meta-analysis of randomized controlled trials to compare 6 HER2-targeted treatment regimens and 1 naïve standard treatment (NST, without any-targeted drugs) in targeted treatment of HER2+ breast cancer in adults. These treatment regimens were T-DM1, LC (lapatinib), HC (trastuzumab), PEC (pertuzumab), LHC (lapatinib and trastuzumab), and PEHC (pertuzumab and trastuzumab). The main outcomes were overall survival and response rates. We also examined side effects of rash, LVEF (left ventricular ejection fraction), fatigue, and gastrointestinal disorders, and performed subgroup analysis for the different treatment regimens in metastatic or advanced breast cancer. Results We identified 25 articles of 21 trials, with data for 11,276 participants. T-DM1 and PEHC were more efficient drug regimens with regard to overall survival as compared with LHC, LC, HC and PEC. The incidence of treatment-related rash occurs more frequently in the patients who received LC treatment regimen than PEHC and T-DM1 and HC. In subgroup analysis, T-DM1 was associated with increased overall survival as compared with LC and HC. PEHC was associated with increased overall response as compared with LC, HC, and NST. Conclusions Overall, the regimen of T-DM1 as well as pertuzumab in combination with trastuzumab and docetaxel is efficacious with fewer side effects as compared with other regimens

  16. 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.

  17. Power law in firms bankruptcy

    NASA Astrophysics Data System (ADS)

    Hong, Byoung Hee; Lee, Kyoung Eun; Lee, Jae Woo

    2007-01-01

    We consider the scaling behaviors for fluctuations of the number of Korean firms bankrupted in the period from 1 August 2002 to 28 October 2003. We observe a power law for the distribution of the number of the bankrupted firms. The Pareto exponent is close to unity. We also consider the daily increments of the number of firms bankrupted. The probability distribution of the daily increments for the firms bankrupted follows the Gaussian distribution in central part and has a fat tail. The tail parts of the probability distribution of the daily increments for the firms bankrupted follow a power law.

  18. 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.

  19. Scaling Behavior of Firm Growth

    NASA Astrophysics Data System (ADS)

    Stanley, Michael H. R.; Nunes Amaral, Luis A.; Buldyrev, Sergey V.; Havlin, Shlomo; Leschhorn, Heiko; Maass, Philipp; Salinger, Michael A.; Stanley, H. Eugene

    1996-03-01

    The theory of the firm is of considerable interest in economics. The standard microeconomic theory of the firm is largely a static model and has thus proved unsatisfactory for addressing inherently dynamic issues such as the growth of economies. In recent years, many have attempted to develop richer models that provide a more accurate representation of firm dynamics due to learning, innovative effort, and the development of organizational infrastructure. The validity of these new, inherently dynamic theories depends on their consistency with the statistical properties of firm growth, e.g. the relationship between growth rates and firm size. Using the Compustat database over the time period 1975-1991, we find: (i) the distribution of annual growth rates for firms with approximately the same sales displays an exponential form with the logarithm of growth rate, and (ii) the fluctuations in the growth rates --- measured by the width of this distribution --- scale as a power law with the firm sales. We place these findings of scaling behavior in the context of conventional economics by considering firm growth dynamics with temporal correlations and also, by considering a hierarchical organization of the departments of a firm.

  20. Zipf law in firms bankruptcy

    NASA Astrophysics Data System (ADS)

    Fujiwara, Yoshi

    2004-06-01

    Using an exhaustive list of Japanese bankruptcy in 1997, we discover a Zipf law for the distribution of total liabilities of bankrupted firms in high debt range. The life-time of these bankrupted firms has exponential distribution in correlation with entry rate of new firms. We also show that the debt and size are highly correlated, so the Zipf law holds consistently with that for size distribution. In an attempt to understand “physics” of bankruptcy, we show that a model of debtor-creditor dynamics of firms and a bank, recently proposed by economists, can reproduce these phenomenological findings.

  1. 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…

  2. 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. PMID:26562429

  3. 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

  4. 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

  5. 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.

  6. 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

  7. 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.

  8. 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. PMID:21079292

  9. 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.

  10. 10 CFR 603.1230 - Commercial firm.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 10 Energy 4 2010-01-01 2010-01-01 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...

  11. 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...

  12. 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...

  13. 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 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...

  14. 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...

  15. 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,…

  16. 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

    2016-06-01

    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.

  17. 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.

  18. 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.

  19. An evolutionary inspection game with labour unions on small-world networks

    NASA Astrophysics Data System (ADS)

    Kamal, Salahuddin M.; Al-Hadeethi, Yas; Abolaban, Fouad A.; Al-Marzouki, Fahd M.; Perc, Matjaž

    2015-03-01

    We study an evolutionary inspection game where agents can chose between working and shirking. The evolutionary process is staged on a small-world network, through which agents compare their incomes and, based on the outcome, decide which strategy to adopt. Moreover, we introduce union members that have certain privileges, of which the extent depends on the bargaining power of the union. We determine how the union affects the overall performance of the firm that employs the agents, and what are its influences on the employees. We find that, depending on its bargaining power, the union has significant leverage to deteriorate the productivity of a firm, and consequently also to lower the long-run benefits of the employees.

  20. 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)

  1. 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

  2. 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.

  3. Disability Management in Small Firms.

    ERIC Educational Resources Information Center

    Drury, David

    1991-01-01

    Notes that American research has paid relatively little attention to prospects for adapting disability management practices to financial and management environment of smaller employers. Compares large and small firms in terms of employer disability practices and characteristics of disabled workers; discusses barriers to rehabilitation and…

  4. 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 on…

  5. 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

  6. Correlation in business networks

    NASA Astrophysics Data System (ADS)

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

    2006-10-01

    This paper considers business networks. Through empirical study, we show that business networks display characteristics of small-world networks and scale-free networks. In this paper, we characterize firms as sales and bankruptcy probabilities. A correlation between sales and a correlation between bankruptcy probabilities in business networks are also considered. The results reveal that the correlation between sales depends strongly on the type of network, whereas the correlation between bankruptcy probabilities does so only weakly.

  7. 7 CFR 51.1824 - Firm.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Standards for Grades of Florida Tangerines Definitions § 51.1824 Firm. Firm means that the flesh is not soft and the fruit is not badly puffy and that the skin has not become materially separated from the...

  8. 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…

  9. Simple models of firms emergence

    NASA Astrophysics Data System (ADS)

    Weisbuch, Gérard; Mangalagiu, Diana; Ben-Av, Radel; Solomon, Sorin

    2008-09-01

    We present a dynamical model of the emergence of firms as opposed to a flat labour market where entrepreneurs would recruit workers for each business opportunity. The model uses a preferential choice of partners based on previous collaborations experience. A sharp transition in the parameter space separates an ordered regime, where preferential links establish, from a disordered regime corresponding to a fast turnover of employees.

  10. 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. PMID:26745375

  11. 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

  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. 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. PMID:27174582

  14. 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…

  15. Agent Orange

    MedlinePlus

    ... Index Agent Orange Agent Orange Home Facts about Herbicides Veterans' Diseases Birth Defects Benefits Exposure Locations Provider ... millions of gallons of Agent Orange and other herbicides on trees and vegetation during the Vietnam War. ...

  16. 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

  17. 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

  18. 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…

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

    PubMed

    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

  20. 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.

  1. Effects of the turnover rate on the size distribution of firms: An application of the kinetic exchange models

    NASA Astrophysics Data System (ADS)

    Chakrabarti, Anindya S.

    2012-12-01

    We address the issue of the distribution of firm size. To this end we propose a model of firms in a closed, conserved economy populated with zero-intelligence agents who continuously move from one firm to another. We then analyze the size distribution and related statistics obtained from the model. There are three well known statistical features obtained from the panel study of the firms i.e., the power law in size (in terms of income and/or employment), the Laplace distribution in the growth rates and the slowly declining standard deviation of the growth rates conditional on the firm size. First, we show that the model generalizes the usual kinetic exchange models with binary interaction to interactions between an arbitrary number of agents. When the number of interacting agents is in the order of the system itself, it is possible to decouple the model. We provide exact results on the distributions which are not known yet for binary interactions. Our model easily reproduces the power law for the size distribution of firms (Zipf’s law). The fluctuations in the growth rate falls with increasing size following a power law (though the exponent does not match with the data). However, the distribution of the difference of the firm size in this model has Laplace distribution whereas the real data suggests that the difference of the log of sizes has the same distribution.

  2. 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.

  3. 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.

  4. Biological Agents

    MedlinePlus

    ... to Z Index Contact Us FAQs What's New Biological Agents This page requires that javascript be enabled ... and Health Topics A-Z Index What's New Biological agents include bacteria, viruses, fungi, other microorganisms and ...

  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. PMID:26327407

  6. Infinitesimal Firms and Increasing Cost Industries.

    ERIC Educational Resources Information Center

    Peck, Richard M.

    2001-01-01

    Presents a rigorous version of the model of an increasing-cost competitive industry. Explains that in this model firms are infinitesimal, which justifies price-taking behavior and a continuous industry supply curve. Shows that the industry supply curve slopes upward because of dispersion in the efficiency of firms. Emphasizes role of marginal…

  7. 32 CFR 37.1250 - Commercial firm.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 1 2010-07-01 2010-07-01 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....

  8. 40 CFR 745.89 - Firm certification.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 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 Renovation § 745.89 Firm certification. (a)...

  9. 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.

  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. 78 FR 70987 - Proxy Advisory Firm Roundtable

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-27

    ...The Securities and Exchange Commission will host a roundtable about proxy advisory firms. The panel will be asked to discuss topics including the current state of proxy advisory firm use by investment advisers and institutional investors and potential changes that have been suggested by market participants. Panelists will also be invited to discuss any new ideas. The roundtable discussion will......

  12. 48 CFR 519.7006 - Mentor firms.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 4 2010-10-01 2010-10-01 false Mentor firms. 519.7006... PROGRAMS SMALL BUSINESS PROGRAMS GSA Mentor-Protégé Program 519.7006 Mentor firms. (a) Mentors must be... plan as required by FAR 19.7 - Small business mentors are exempted; or (2) A small business...

  13. 48 CFR 519.7006 - Mentor firms.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 4 2013-10-01 2013-10-01 false Mentor firms. 519.7006... PROGRAMS SMALL BUSINESS PROGRAMS GSA Mentor-Protégé Program 519.7006 Mentor firms. (a) Mentors must be... plan as required by FAR 19.7 - Small business mentors are exempted; or (2) A small business...

  14. 48 CFR 519.7006 - Mentor firms.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 4 2012-10-01 2012-10-01 false Mentor firms. 519.7006... PROGRAMS SMALL BUSINESS PROGRAMS GSA Mentor-Protégé Program 519.7006 Mentor firms. (a) Mentors must be... plan as required by FAR 19.7 - Small business mentors are exempted; or (2) A small business...

  15. 48 CFR 519.7006 - Mentor firms.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 4 2014-10-01 2014-10-01 false Mentor firms. 519.7006... PROGRAMS SMALL BUSINESS PROGRAMS GSA Mentor-Protégé Program 519.7006 Mentor firms. (a) Mentors must be... plan as required by FAR 19.7 - Small business mentors are exempted; or (2) A small business...

  16. 48 CFR 519.7006 - Mentor firms.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 4 2011-10-01 2011-10-01 false Mentor firms. 519.7006... PROGRAMS SMALL BUSINESS PROGRAMS GSA Mentor-Protégé Program 519.7006 Mentor firms. (a) Mentors must be... plan as required by FAR 19.7 - Small business mentors are exempted; or (2) A small business...

  17. 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.…

  18. 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…

  19. AGENT-BASED MODELING OF INDUSTRIAL ECOSYSTEMS

    EPA Science Inventory

    The objectives of this research are to investigate behavioral and organizational questions associated with environmental regulation of firms, and to test specifically whether a bottom-up approach that highlights principal-agent problems offers new insights and empirical validi...

  20. Manufacturing firms' decisions regarding retiree health insurance.

    PubMed

    Born, Patricia H; Zawacki, Alice M

    2006-01-01

    The trend for employers to discontinue offering retiree health insurance has profound implications for a large and growing share of the U.S. older population. The authors explore factors related to the firm's decision to offer and contribute to retiree health insurance using data from manufacturing firms. Their findings indicate that while firm characteristics, such as size and age, affect the probability that a firm offers retiree health insurance, employer contributions to this benefit are significantly related to the firm's financial performance and the alternative insurance options available in the market. The article concludes with a brief discussion of policy-related measures with potentially important implications for the future of retiree health benefits. PMID:16792390

  1. 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.

  2. 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

  3. Agent amplified communication

    SciTech Connect

    Kautz, H.; Selman, B.; Milewski, A.

    1996-12-31

    We propose an agent-based framework for assisting and simplifying person-to-person communication for information gathering tasks. As an example, we focus on locating experts for any specified topic. In our approach, the informal person-to-person networks that exist within an organization are used to {open_quotes}referral chain{close_quotes} requests for expertise. User-agents help automate this process. The agents generate referrals by analyzing records of e-mail communication patterns. Simulation results show that the higher responsiveness of an agent-based system can be effectively traded for the higher accuracy of a completely manual approach. Furthermore, preliminary experience with a group of users on a prototype system has shown that useful automatic referrals can be found in practice. Our experience with actual users has also shown that privacy concerns are central to the successful deployment of personal agents: an advanced agent-based system will therefore need to reason about issues involving trust and authority.

  4. 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

  5. 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. PMID:27158285

  6. Efficacy of Second Generation Direct-Acting Antiviral Agents for Treatment Naïve Hepatitis C Genotype 1: A Systematic Review and Network Meta-Analysis

    PubMed Central

    Sobhonslidsuk, Abhasnee; Thakkinstian, Ammarin; Teerawattananon, Yot

    2015-01-01

    Background The treatment of hepatitis C (HCV) infections has significantly changed in the past few years due to the introduction of direct-acting antiviral agents (DAAs). DAAs could improve the sustained virological response compared to pegylated interferon with ribavirin (PR). However, there has been no evidence from randomized controlled trials (RCTs) that directly compare the efficacy among the different regimens of DAAs. Aim Therefore, we performed a systematic review and network meta-analysis aiming to compare the treatment efficacy between different DAA regimens for treatment naïve HCV genotype 1. Methods Medline and Scopus were searched up to 25th May 2015. RCTs investigating the efficacy of second generation DAA regimens for treatment naïve HCV genotype 1 were eligible for the review. Due to the lower efficacy and more side effects of first generation DAAs, this review included only second generation DAAs approved by the US or EU Food and Drug Administration, that comprised of simeprevir (SMV), sofosbuvir (SOF), daclatasvir (DCV), ledipasvir (LDV), and paritaprevir/ritonavir/ombitasvir plus dasabuvir (PrOD). Primary outcomes were sustained virological response at weeks 12 (SVR12) and 24 (SVR24) after the end of treatment and adverse drug events (i.e. serious adverse events, anemia, and fatigue). Efficacy of all treatment regimens were compared by applying a multivariate random effect meta-analysis. Incidence rates of SVR12 and SVR24, and adverse drug events of each treatment regimen were pooled using ‘pmeta’ command in STATA program. Results Overall, 869 studies were reviewed and 16 studies were eligible for this study. Compared with the PR regimen, SOF plus PR, SMV plus PR, and DVC plus PR regimens yielded significantly higher probability of having SVR24 with pooled risk ratios (RR) of 1.98 (95% CI 1.24, 3.14), 1.46 (95% CI: 1.22, 1.75), and 1.68 (95% CI: 1.14, 2.46), respectively. Pooled incidence rates of SVR12 and SVR24 in all treatment regimens

  7. 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)...

  8. 49 CFR 1522.103 - Requirements for validation firms.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 9 2010-10-01 2010-10-01 false Requirements for validation firms. 1522.103...-APPROVED VALIDATION FIRMS AND VALIDATORS TSA-Approved Validation Firms and Validators for the Certified Cargo Screening Program § 1522.103 Requirements for validation firms. In addition to the...

  9. 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...

  10. 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...

  11. Cournot competition between a non-profit firm and a for-profit firm with uncertainty

    NASA Astrophysics Data System (ADS)

    Ferreira, Fernanda A.

    2010-03-01

    In this paper, we consider a Cournot competition between a nonprofit firm and a for-profit firm in a homogeneous goods market, with uncertain demand. Given an asymmetric tax schedule, we compute explicitly the Bayesian-Nash equilibrium. Furthermore, we analyze the effects of the tax rate and the degree of altruistic preference on market equilibrium outcomes.

  12. 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.

  13. 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

  14. 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.

  15. 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 ...

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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…

  1. TOWARDS A THEORY OF THE EDUCATIONAL FIRM.

    ERIC Educational Resources Information Center

    SIEGEL, BARRY N.

    THIS PAPER DEVELOPS AN ECONOMIC THEORY OF INSTITUTIONS OF HIGHER EDUCATION (IHE) FROM WHICH IT MIGHT BE POSSIBLE TO EXTRACT A THEORY OF ENROLLMENT SUPPLY. SUCH A THEORY MUST DIFFER RADICALLY FROM THE THEORY OF THE BUSINESS FIRM BECAUSE OF TWO KEY ASSUMPTIONS WHICH CANNOT BE MADE ABOUT THE IHE--PROFIT MAXIMIZATION AND A PRODUCTION FUNCTION WHICH…

  2. 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...

  3. 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...

  4. 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...

  5. 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...

  6. 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…

  7. The Founding of Technologically-Based Firms.

    ERIC Educational Resources Information Center

    Cooper, Arnold C.

    This monograph describes a study of entrepreneurship in new technologically-based firms. The work is based on empirical data gathered primarily in interviews with individuals who formed such enterprises. Most of the research was conducted in one of the nation's centers of technological entrepreneurship, the San Francisco Peninsula area around Palo…

  8. 24 CFR 200.47 - Firm commitments.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... DEVELOPMENT GENERAL INTRODUCTION TO FHA PROGRAMS Requirements for Application, Commitment, and Endorsement... 24 Housing and Urban Development 2 2013-04-01 2013-04-01 false Firm commitments. 200.47 Section 200.47 Housing and Urban Development Regulations Relating to Housing and Urban Development...

  9. 24 CFR 200.47 - Firm commitments.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... DEVELOPMENT GENERAL INTRODUCTION TO FHA PROGRAMS Requirements for Application, Commitment, and Endorsement... 24 Housing and Urban Development 2 2012-04-01 2012-04-01 false Firm commitments. 200.47 Section 200.47 Housing and Urban Development Regulations Relating to Housing and Urban Development...

  10. 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...

  11. 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... 24 Housing and Urban Development 2 2011-04-01 2011-04-01 false Firm commitments. 200.47 Section 200.47 Housing and Urban Development Regulations Relating to Housing and Urban Development...

  12. 24 CFR 200.47 - Firm commitments.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... DEVELOPMENT GENERAL INTRODUCTION TO FHA PROGRAMS Requirements for Application, Commitment, and Endorsement... 24 Housing and Urban Development 2 2014-04-01 2014-04-01 false Firm commitments. 200.47 Section 200.47 Housing and Urban Development Regulations Relating to Housing and Urban Development...

  13. Battlefield agent collaboration

    NASA Astrophysics Data System (ADS)

    Budulas, Peter P.; Young, Stuart H.; Emmerman, Philip J.

    2001-09-01

    Small air and ground physical agents (robots) will be ubiquitous on the battlefield of the 21st century, principally to lower the exposure to harm of our ground forces in urban and open terrain scenarios. Teams of small collaborating physical agents conducting tasks such as Reconnaissance, Surveillance, and Target Acquisition (RSTA), intelligence, chemical and biological agent detection, logistics, decoy, sentry; and communications relay will have advanced sensors, communications, and mobility characteristics. It is anticipated that there will be many levels of individual and team collaboration between the soldier and robot, robot to robot, and robot to mother ship. This paper presents applications and infrastructure components that illustrate each of these levels. As an example, consider the application where a team of twenty small robots must rapidly explore and define a building complex. Local interactions and decisions require peer to peer collaboration. Global direction and information fusion warrant a central team control provided by a mother ship. The mother ship must effectively deliver/retrieve, service, and control these robots as well as fuse the information gathered by these highly mobile robot teams. Any level of collaboration requires robust communications, specifically a mobile ad hoc network. The application of fixed ground sensors and mobile robots is also included in this paper. This paper discusses on going research at the U.S. Army Research Laboratory that supports the development of multi-robot collaboration. This research includes battlefield visualization, intelligent software agents, adaptive communications, sensor and information fusion, and multi-modal human computer interaction.

  14. 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

  15. 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

  16. 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.

  17. Antiparasitic agents.

    PubMed

    Rosenblatt, J E

    1999-11-01

    Several important developments have occurred in recent years in the chemotherapy for and prophylaxis of parasitic infections. Although mefloquine is clearly the most effective agent for prevention of chloroquine-resistant falciparum malaria, its use has been compromised by side effects, both real and imagined. Well-designed studies have shown that side effects occur no more frequently with low-dose mefloquine than with chloroquine. Use of mefloquine in pregnant women has not been associated with birth defects, but the incidence of stillbirths may be increased. Malarone is a new agent that combines atovaquone and proguanil, and it may be as effective as mefloquine; however, it is not yet available in the United States. Several newer agents have appeared in response to the development of multidrug resistant Plasmodium falciparum, especially in Southeast Asia. Halofantrine is available for the treatment of mild to moderate malaria due to P. falciparum and for P. vivax infections. Because of severe toxic effects, use of halofantrine should be restricted to only those unusual and rare situations in which other agents cannot be used. Artemisinin (an extract of the Chinese herbal remedy qinghaosu) and two derivatives, artesunate and artemether, are active against multidrug resistant P. falciparum and are widely used in Asia in oral, parenteral, and rectal forms. The antibacterial azithromycin in combination with atovaquone or quinine has now been reported to treat babesiosis effectively in experimental animals and in a few patients. Azithromycin in combination with paromomycin has also shown promise in the treatment of cryptosporidiosis (and toxoplasmosis when combined with pyrimethamine) in patients with the acquired immunodeficiency syndrome (AIDS). Albendazole is currently the only systemic agent available for treatment of microsporidiosis, an infection primarily of patients with AIDS. In addition, albendazole and ivermectin have emerged as effective broad

  18. 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. PMID:23971143

  19. 39 CFR 281.1 - Notification of firm mailers.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... DESTROYED THROUGH TRANSPORTATION ACCIDENTS OR CATASTROPHES § 281.1 Notification of firm mailers. Whenever bulk firm mail shipments are involved in transportation accidents or catastrophes, such as train...

  20. 39 CFR 281.1 - Notification of firm mailers.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... DESTROYED THROUGH TRANSPORTATION ACCIDENTS OR CATASTROPHES § 281.1 Notification of firm mailers. Whenever bulk firm mail shipments are involved in transportation accidents or catastrophes, such as train...

  1. 39 CFR 281.1 - Notification of firm mailers.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... DESTROYED THROUGH TRANSPORTATION ACCIDENTS OR CATASTROPHES § 281.1 Notification of firm mailers. Whenever bulk firm mail shipments are involved in transportation accidents or catastrophes, such as train...

  2. 39 CFR 281.1 - Notification of firm mailers.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... DESTROYED THROUGH TRANSPORTATION ACCIDENTS OR CATASTROPHES § 281.1 Notification of firm mailers. Whenever bulk firm mail shipments are involved in transportation accidents or catastrophes, such as train...

  3. 39 CFR 281.1 - Notification of firm mailers.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... DESTROYED THROUGH TRANSPORTATION ACCIDENTS OR CATASTROPHES § 281.1 Notification of firm mailers. Whenever bulk firm mail shipments are involved in transportation accidents or catastrophes, such as train...

  4. Antifungal agents.

    PubMed

    Ryder, N S

    1999-12-01

    At this year's ICAAC Meeting, new data on approximately 20 different antifungal agents were presented, while no new agents were disclosed. Drugs in late development include the triazoles, voriconazole (Pfizer Ltd) and Sch-56592 (Schering-Plough Corp), and the echinocandins, caspofungin (Merck & Co Inc) and FK-463 (Fujisawa Pharmaceutical Co Ltd). In contrast to previous years, presentations on these and earlier developmental compounds were relatively modest in scope, with few significant new data. Little new information appeared on the most recent novel class of agents, the sordarins (Glaxo Wellcome plc). Early clinical results were presented for FK-463, showing acceptable tolerability and dose-dependent efficacy in AIDS-associated esophageal candidiasis. A new liposomal formulation of nystatin (Nyotran; Aronex Pharmaceuticals Inc) was shown to be equivalent to conventional amphotericin B in empiric therapy of presumed fungal infection in neutropenic patients, but with reduced toxicity. Intravenous itraconazole (Janssen Pharmaceutica NV) was an effective prophylactic therapy in invasive pulmonary aspergillosis, while oral itraconazole was discussed as a treatment for fungal infection in heart and liver transplant patients. The allylamine compound, terbinafine (Novartis AG), showed good clinical efficacy against fungal mycetoma, a serious tropical infection. A major highlight was the first presentation of inhibitors of fungal efflux pumps as a strategy for overcoming resistance. MC-510027 (milbemycin alpha-9; Microcide Pharmaceuticals Inc) and its derivatives, potentiated the antifungal activity of triazoles and terbinafine in a number of Candida spp. Another pump inhibitor, MC-005172 (Microcide Pharmaceuticals Inc) showed in vivo potentiation of fluconazole in a mouse kidney infection model. Microcide Pharmaceuticals Inc also presented inhibitors of bacterial efflux pumps. PMID:16113946

  5. 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.

  6. The Short-Run Expansion Path for the Firm

    ERIC Educational Resources Information Center

    Jones, Clifton T.; Thompson, Mark A.

    2007-01-01

    There is some confusion about the nature of the short-run expansion path (SREP) for the firm as presented in many intermediate microeconomics textbooks. The traditional view is that the SREP is a horizontal line because the firm is stuck with a fixed amount of capital. However, this view does not usually acknowledge that the firm could choose to…

  7. 48 CFR 1019.202-70-7 - Mentor firms.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Mentor firms. 1019.202-70... SOCIOECONOMIC PROGRAMS SMALL BUSINESS PROGRAMS Policies 1019.202-70-7 Mentor firms. A mentor firm may be either... developmental assistance to enhance the capabilities of protégés to perform as subcontractors. Mentors will...

  8. 37 CFR 10.35 - Firm names and letterheads.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 37 Patents, Trademarks, and Copyrights 1 2011-07-01 2011-07-01 false Firm names and letterheads... Office Code of Professional Responsibility § 10.35 Firm names and letterheads. (a) A practitioner shall not use a firm name, letterhead, or other professional designation that violates § 10.31. A trade...

  9. 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... Office Code of Professional Responsibility § 10.35 Firm names and letterheads. (a) A practitioner shall not use a firm name, letterhead, or other professional designation that violates § 10.31. A trade...

  10. 37 CFR 10.35 - Firm names and letterheads.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 37 Patents, Trademarks, and Copyrights 1 2010-07-01 2010-07-01 false Firm names and letterheads... Office Code of Professional Responsibility § 10.35 Firm names and letterheads. (a) A practitioner shall not use a firm name, letterhead, or other professional designation that violates § 10.31. A trade...

  11. 37 CFR 11.705 - Firm names and letterheads.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 37 Patents, Trademarks, and Copyrights 1 2014-07-01 2014-07-01 false Firm names and letterheads... Rules of Professional Conduct Information About Legal Services § 11.705 Firm names and letterheads. (a) A practitioner shall not use a firm name, letterhead or other professional designation that...

  12. 37 CFR 11.705 - Firm names and letterheads.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 37 Patents, Trademarks, and Copyrights 1 2013-07-01 2013-07-01 false Firm names and letterheads... Rules of Professional Conduct Information About Legal Services § 11.705 Firm names and letterheads. (a) A practitioner shall not use a firm name, letterhead or other professional designation that...

  13. 21 CFR 7.46 - Firm-initiated recall.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 1 2014-04-01 2014-04-01 false Firm-initiated recall. 7.46 Section 7.46 Food and... Recalls (Including Product Corrections)-Guidance on Policy, Procedures, and Industry Responsibilities § 7.46 Firm-initiated recall. (a) A firm may decide of its own volition and under any circumstances...

  14. 21 CFR 7.46 - Firm-initiated recall.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 1 2013-04-01 2013-04-01 false Firm-initiated recall. 7.46 Section 7.46 Food and... Recalls (Including Product Corrections)-Guidance on Policy, Procedures, and Industry Responsibilities § 7.46 Firm-initiated recall. (a) A firm may decide of its own volition and under any circumstances...

  15. 21 CFR 7.46 - Firm-initiated recall.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 1 2012-04-01 2012-04-01 false Firm-initiated recall. 7.46 Section 7.46 Food and... Recalls (Including Product Corrections)-Guidance on Policy, Procedures, and Industry Responsibilities § 7.46 Firm-initiated recall. (a) A firm may decide of its own volition and under any circumstances...

  16. 21 CFR 7.46 - Firm-initiated recall.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 1 2011-04-01 2011-04-01 false Firm-initiated recall. 7.46 Section 7.46 Food and... Recalls (Including Product Corrections)-Guidance on Policy, Procedures, and Industry Responsibilities § 7.46 Firm-initiated recall. (a) A firm may decide of its own volition and under any circumstances...

  17. 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

  18. Assessing the three-dimensional collagen network in soft tissues using contrast agents and high resolution micro-CT: Application to porcine iliac veins.

    PubMed

    Nierenberger, Mathieu; Rémond, Yves; Ahzi, Saïd; Choquet, Philippe

    2015-07-01

    The assessment of the three-dimensional architecture of collagen fibers inside vessel walls constitutes one of the bases for building structural models for the description of the mechanical behavior of these tissues. Multiphoton microscopy allows for such observations, but is limited to volumes of around a thousand of microns. In the present work, we propose to observe the collagenous network of vascular tissues using micro-CT. To get a contrast, three staining solutions (phosphotungstic acid, phosphomolybdic acid and iodine potassium iodide) were tested. Two of these stains were showed to lead to similar results and to a satisfactory contrast within the tissue. A detailed observation of a small porcine iliac vein sample allowed assessing the collagen fibers orientations within the medial and adventitial layers of the vein. The vasa vasorum network, which is present inside the adventitia of the vein, was also observed. Finally, the demonstrated micro-CT staining technique for the three-dimensional observation of thin soft tissues samples, like vein walls, contributes to the assessment of their structure at different scales while keeping a global overview of the tissue. PMID:26033495

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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…

  4. The complex metabolic network gearing the G1/S transition in leukemic stem cells: Hints to a rational use of antineoplastic agents

    PubMed Central

    D'Amico, Massimo; Mannini, Antonella; Mini, Enrico; Rovida, Elisabetta; Dello Sbarba, Persio; Olivotto, Massimo; Marzi, Ilaria

    2015-01-01

    We defined the stem cell profile of K562 line, demonstrating the expression of the Embryonic Transcription Factors Oct3/4, Sox2, Klf4 and Nanog. This profile was associated with a high vulnerability to the physiological oxidizable substrate pyruvate. remarkably, this substrate was shown to be innocuous, even at the highest doses, to normal differentiated cells. This vulnerability is based on a complex metabolic trim centered on the cellular redox state expressed by the NADP/NADPH ratio geared by the mitochondrial respiratory chain. Flow cytometry revealed that the inhibition of this chain by antimycin A produced cell accumulation in the S phase of cell cycle and apoptosis. This block negatively interferes with the aerobic synthesis of purines, without affecting the anaerobic synthesis of pyrimidines. This imbalance was reproduced by using two antifolate agents, LY309887 and raltitrexed (TDX), inhibitors of purine or pyrimidine synthesis, respectively. All this revealed the apparent paradox that low doses of TDX stimulated, instead of inhibiting, leukemia cell growth. This paradox might have significant impact on therapy with regard to the effects of TDX during the intervals of administration, when the drug concentrations become so low as to promote maintenance of dormant cancer cells in hypoxic tissue niches. PMID:26396171

  5. 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.

  6. 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

    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

  7. 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 ...

  8. Agent Building Software

    NASA Technical Reports Server (NTRS)

    2000-01-01

    AgentBuilder is a software component developed under an SBIR contract between Reticular Systems, Inc., and Goddard Space Flight Center. AgentBuilder allows software developers without experience in intelligent agent technologies to easily build software applications using intelligent agents. Agents are components of software that will perform tasks automatically, with no intervention or command from a user. AgentBuilder reduces the time and cost of developing agent systems and provides a simple mechanism for implementing high-performance agent systems.

  9. 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.

  10. 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.

  11. 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.

  12. NISAC Agent Based Laboratory for Economics

    Energy Science and Technology Software Center (ESTSC)

    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 interactmore » 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.« less

  13. Peer group ties and executive compensation networks.

    PubMed

    Pittinsky, Matthew; Diprete, Thomas A

    2013-11-01

    Publicly traded firms in the US typically determine C.E.O. compensation by benchmarking the pay of their C.E.O.s against the pay of C.E.O.s in "peer" firms. Consequently, executive compensation is influenced not only by firm-level characteristics, but also by the selection and actions of the firm's immediate peers as well as by the structure of the executive compensation network overall. Analyzing compensation peer group choices made by the same 1183 firms for F.Y. 2007, 2008 and 2009, we find that while the typical compensation peer is similar in size and industry to the firm that chose it, deviations from this norm are common, especially among larger firms, and tend to be towards larger firms with better paid CEOs. Further analysis shows that firms who pay CEOs well relative to the pay that would be predicted from their revenues, return on assets, and industry tend to have greater aspiration bias in their group of named peers. PMID:24090860

  14. 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.

  15. 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.

  16. Applications of Multi-Agent Technology to Power Systems

    NASA Astrophysics Data System (ADS)

    Nagata, Takeshi

    Currently, agents are focus of intense on many sub-fields of computer science and artificial intelligence. Agents are being used in an increasingly wide variety of applications. Many important computing applications such as planning, process control, communication networks and concurrent systems will benefit from using multi-agent system approach. A multi-agent system is a structure given by an environment together with a set of artificial agents capable to act on this environment. Multi-agent models are oriented towards interactions, collaborative phenomena, and autonomy. This article presents the applications of multi-agent technology to the power systems.

  17. 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.

  18. 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.

  19. A Multi-agent Approach to Distribution System Restoration

    NASA Astrophysics Data System (ADS)

    Nagata, Takeshi; Tao, Yasuhiro; Sasaki, Hiroshi; Fujita, Hideki

    This paper proposes a multi-agent approach to decentralized power system restoration for a distribution system network. The proposed method consists of several Feeder Agents (FAGs) and Load Agents (LAGs). LAG corresponds to the customer load, while a FAG is developed to act as a manager for the decision process. From the simulation results, it can be seen the proposed multi-agent system could reach the right solution by making use of only local information. This means that the proposed multi-agent restoration system is a promising approach to more large-scale distribution networks.

  20. Mother ship and physical agents collaboration

    NASA Astrophysics Data System (ADS)

    Young, Stuart H.; Budulas, Peter P.; Emmerman, Philip J.

    1999-07-01

    This paper discusses ongoing research at the U.S. Army Research Laboratory that investigates the feasibility of developing a collaboration architecture between small physical agents and a mother ship. This incudes the distribution of planning, perception, mobility, processing and communications requirements between the mother ship and the agents. Small physical agents of the future will be virtually everywhere on the battlefield of the 21st century. A mother ship that is coupled to a team of small collaborating physical agents (conducting tasks such as Reconnaissance, Surveillance, and Target Acquisition (RSTA); logistics; sentry; and communications relay) will be used to build a completely effective and mission capable intelligent system. The mother ship must have long-range mobility to deploy the small, highly maneuverable agents that will operate in urban environments and more localized areas, and act as a logistics base for the smaller agents. The mother ship also establishes a robust communications network between the agents and is the primary information disseminating and receiving point to the external world. Because of its global knowledge and processing power, the mother ship does the high-level control and planning for the collaborative physical agents. This high level control and interaction between the mother ship and its agents (including inter agent collaboration) will be software agent architecture based. The mother ship incorporates multi-resolution battlefield visualization and analysis technology, which aids in mission planning and sensor fusion.

  1. How national institutions influence firms' knowledge-building alliance strategies: A longitudinal study of fuel cell technology development

    NASA Astrophysics Data System (ADS)

    Vasudeva, Gurneeta

    This study posited knowledge-building alliance strategies as a function of the national institutional environment characterizing the firm's location of innovation. Hypotheses were grounded in two dimensions of institutional theory---the location of authority in a strong state apparatus or statism, and organization of society along communitarian principles or corporatism. Based on their utility in explaining both innovation and collaboration, these institutional dimensions were conceptualized as influencing firms' knowledge-building alliance strategies directly, and by interacting with firm-, dyad- and network-level characteristics such as size, technological achievement, technological distance and social capital. Results showed that corporatism did not contribute to significantly more alliances, though a positive and significant relationship was observed in estimating alliances with research institutions. Similarly, statism was found to be associated with increased alliances with foreign actors. Large, technologically accomplished firms engaged in more alliances across polities, however, smaller, less technologically accomplished firms engaged in greater number of alliances in corporatist polities than associational polities. Technological distance between partners reduced the odds of alliance formation; this relationship, however, was stronger in societal polities than statist polities. Alliances served as a significant mechanism for knowledge spillovers across both polity types. Even though alliance counts did not vary according to the degree of corporatism, the motivation to build on both direct and indirect partners' knowledge did. Firms in associational polities built on their partners' knowledge more successfully than firms from corporatist polities; however, the proportion of knowledge acquired from foreign partners was lower in statist polities. The social capital generated from strong brokerage positions spanned by the firms was associated with greater

  2. Controlling firms through the majority voting rule

    NASA Astrophysics Data System (ADS)

    Chapelle, Ariane; Szafarz, Ariane

    2005-09-01

    Pyramids, cross-ownership, rings and other complex features inducing control tunnelling are frequent in the European and Asian industrial world. Based on the matrix methodology, this paper offers a model for measuring integrated ownership and threshold-based control, applicable to any group of interrelated firms. In line with the theory on pyramidal control, the model avoids the double counting problem and sets the full control threshold at the conservative-but incontestable-majority level of 50% of the voting shares. Any lower threshold leads to potential inconsistencies and leaves the observed high level of ownership of many dominant shareholders unexplained. Furthermore, the models leads to ultimate shareholders’ control ratios consistent with the majority voting rule. Finally, it is applied to the Frère Group, a large European pyramidal holding company known for mastering control leverages.

  3. 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

  4. Preparing Change Agents for Change Agent Roles.

    ERIC Educational Resources Information Center

    Sedlacek, James R.

    Seventy-seven Spanish- and Portuguese-speaking agricultural change agents from developing Central and South American countries responded to a questionnaire which sought perceptions of the roles in which the change agents felt they were involved and the roles for which they felt they were being trained. The agents were participating in training…

  5. Mobile agent location in distributed environments

    NASA Astrophysics Data System (ADS)

    Fountoukis, S. G.; Argyropoulos, I. P.

    2012-12-01

    An agent is a small program acting on behalf of a user or an application which plays the role of a user. Artificial intelligence can be encapsulated in agents so that they can be capable of both behaving autonomously and showing an elementary decision ability regarding movement and some specific actions. Therefore they are often called autonomous mobile agents. In a distributed system, they can move themselves from one processing node to another through the interconnecting network infrastructure. Their purpose is to collect useful information and to carry it back to their user. Also, agents are used to start, monitor and stop processes running on the individual interconnected processing nodes of computer cluster systems. An agent has a unique id to discriminate itself from other agents and a current position. The position can be expressed as the address of the processing node which currently hosts the agent. Very often, it is necessary for a user, a processing node or another agent to know the current position of an agent in a distributed system. Several procedures and algorithms have been proposed for the purpose of position location of mobile agents. The most basic of all employs a fixed computing node, which acts as agent position repository, receiving messages from all the moving agents and keeping records of their current positions. The fixed node, responds to position queries and informs users, other nodes and other agents about the position of an agent. Herein, a model is proposed that considers pairs and triples of agents instead of single ones. A location method, which is investigated in this paper, attempts to exploit this model.

  6. Remote Agent Demonstration

    NASA Technical Reports Server (NTRS)

    Dorais, Gregory A.; Kurien, James; Rajan, Kanna

    1999-01-01

    We describe the computer demonstration of the Remote Agent Experiment (RAX). The Remote Agent is a high-level, model-based, autonomous control agent being validated on the NASA Deep Space 1 spacecraft.

  7. Network bipartivity

    NASA Astrophysics Data System (ADS)

    Holme, Petter; Liljeros, Fredrik; Edling, Christofer R.; Kim, Beom Jun

    2003-11-01

    Systems with two types of agents with a preference for heterophilous interaction produce networks that are more or less close to bipartite. We propose two measures quantifying the notion of bipartivity. The two measures—one well known and natural, but computationally intractable, and the other computationally less complex, but also less intuitive—are examined on model networks that continuously interpolate between bipartite graphs and graphs with many odd circuits. We find that the bipartivity measures increase as we tune the control parameters of the test networks to intuitively increase the bipartivity, and thus conclude that the measures are quite relevant. We also measure and discuss the values of our bipartivity measures for empirical social networks (constructed from professional collaborations, Internet communities, and field surveys). Here we find, as expected, that networks arising from romantic online interaction have high, and professional collaboration networks have low, bipartivity values. In some other cases, probably due to low average degree of the network, the bipartivity measures cannot distinguish between romantic and friendship oriented interaction.

  8. 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.

  9. 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.

  10. Safety and effectiveness of dipeptidyl peptidase-4 inhibitors versus intermediate-acting insulin or placebo for patients with type 2 diabetes failing two oral antihyperglycaemic agents: a systematic review and network meta-analysis

    PubMed Central

    Tricco, Andrea C; Antony, Jesmin; Khan, Paul A; Ghassemi, Marco; Hamid, Jemila S; Ashoor, Huda; Blondal, Erik; Soobiah, Charlene; Yu, Catherine H; Hutton, Brian; Hemmelgarn, Brenda R; Moher, David; Majumdar, Sumit R; Straus, Sharon E

    2014-01-01

    Objective To evaluate the effectiveness and safety of dipeptidyl peptidase-4 (DPP-4) inhibitors versus intermediate-acting insulin for adults with type 2 diabetes mellitus (T2DM) and poor glycaemic control despite treatment with two oral agents. Setting Studies were multicentre and multinational. Participants Ten studies including 2967 patients with T2DM. Interventions Studies that examined DPP-4 inhibitors compared with each other, intermediate-acting insulin, no treatment or placebo in patients with T2DM. Primary and secondary outcome measures Primary outcome was glycosylated haemoglobin (HbA1c). Secondary outcomes were healthcare utilisation, body weight, fractures, quality of life, microvascular complications, macrovascular complications, all-cause mortality, harms, cost and cost-effectiveness. Results 10 randomised clinical trials with 2967 patients were included after screening 5831 titles and abstracts, and 180 full-text articles. DPP-4 inhibitors significantly reduced HbA1c versus placebo in network meta-analysis (NMA; mean difference (MD) −0.62%, 95% CI −0.93% to −0.33%) and meta-analysis (MD −0.61%, 95% CI −0.81% to −0.41%), respectively. Significant differences in HbA1c were not observed for neutral protamine Hagedorn (NPH) insulin versus placebo and DPP-4 inhibitors versus NPH insulin in NMA. In meta-analysis, no significant differences were observed between DPP-4 inhibitors and placebo for severe hypoglycaemia, weight gain, cardiovascular disease, overall harms, treatment-related harms and mortality, although patients receiving DPP-4 inhibitors experienced less infections (relative risk 0.72, 95% CI 0.57 to 0.91). Conclusions DPP-4 inhibitors were superior to placebo in reducing HbA1c levels in adults with T2DM taking at least two oral agents. Compared with placebo, no safety signals were detected with DPP-4 inhibitors and there was a reduced risk of infection. There was no significant difference in HbA1c observed between NPH and placebo or

  11. 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…

  12. Problems of Small, High-Technology Firms. Special Report.

    ERIC Educational Resources Information Center

    Stewart, William L.; Friedman, Norman W.

    Although small, high-technology firms contribute greatly to major scientific and technical innovations, their potential impact is hindered by financial, personnel, regulatory and other problems. In 1977, the National Science Foundation conducted a survey of firms (N=1,232) presumed to be active in research and development (R&D) and sponsored…

  13. 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).

  14. 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…

  15. 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....

  16. 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....

  17. A NEW BIOYIELD TESTER FOR MEASURING APPLE FRUIT FIRMNESS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Nondestructive sensing of fruit firmness provides the producer and retailer with a means for assessing and/or assuring the quality and consistency of apples delivered to the market. The objective of this research was to evaluate a newly developed bioyield tester for measuring fruit firmness and its...

  18. 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…

  19. 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…

  20. 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…

  1. 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…

  2. Gibrat and Pareto-Zipf revisited with European firms

    NASA Astrophysics Data System (ADS)

    Fujiwara, Yoshi; Aoyama, Hideaki; Di Guilmi, Corrado; Souma, Wataru; Gallegati, Mauro

    2004-12-01

    A firms growth and failure are the two sides of the same coin. This paper reports new phenomenological findings for firm size distribution and growth, and bankruptcy. This paper is based on [Y. Fujiwara et al., Physica A 335 (2004) 197] and on [Y. Fujiwara, Physica A 337 (2004) 219]. See also these proceedings for kinematical relationship between Pareto-Zipf and Gibrat's laws.

  3. Optical recognition of biological agents

    NASA Astrophysics Data System (ADS)

    Baumgart, Chris W.; Linder, Kim Dalton; Trujillo, Josh J.

    2008-04-01

    Differentiation between particulate biological agents and non-biological agents is typically performed via a time-consuming "wet chemistry" process or through the use of fluorescent and spectroscopic analysis. However, while these methods can provide definitive recognition of biological agents, many of them have to be performed in a laboratory environment, or are difficult to implement in the field. Optical recognition techniques offer an additional recognition approach that can provide rapid analysis of a material in-situ to identify those materials that may be biological in nature. One possible application is to use these techniques to "screen" suspicious materials and to identify those that are potentially biological in nature. Suspicious materials identified by this screening process can then be analyzed in greater detail using the other, more definitive (but time consuming) analysis techniques. This presentation will describe the results of a feasibility study to determine whether optical pattern recognition techniques can be used to differentiate biological related materials from non-biological materials. As part of this study, feature extraction algorithms were developed utilizing multiple contrast and texture based features to characterize the macroscopic properties of different materials. In addition, several pattern recognition approaches using these features were tested including cluster analysis and neural networks. Test materials included biological agent simulants, biological agent related materials, and non-biological materials (suspicious white powders). Results of a series of feasibility tests will be presented along with a discussion of the potential field applications for these techniques.

  4. 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. PMID:17368921

  5. 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…

  6. Communities in Italian corporate networks

    NASA Astrophysics Data System (ADS)

    Piccardi, Carlo; Calatroni, Lisa; Bertoni, Fabio

    2010-11-01

    The community structure of two real-world financial networks, namely the board network and the ownership network of the firms of the Italian Stock Exchange, is analyzed by means of the maximum modularity approach. The main result is that both networks exhibit a strong community structure and, moreover, that the two structures overlap significantly. This is due to a number of reasons, including the existence of pyramidal groups and directors serving in several boards. Overall, this means that the “small world” of listed companies is actually split into well identifiable “continents” (i.e., the communities).

  7. A Highly Secure Mobile Agent System Architecture

    NASA Astrophysics Data System (ADS)

    Okataku, Yasukuni; Okutomi, Hidetoshi; Yoshioka, Nobukazu; Ohgishi, Nobuyuki; Honiden, Shinichi

    We propose a system architecture for mobile agents to improve their security in the environments of insecure networks and non-sophisticated terminals such as PDAs. As mobile agents freely migrate onto their favorite terminals through insecure networks or terminals, it is not appropriate for them to store some secret information for authentication and encryption/decryption. We introduce one and more secure nodes(OASIS NODE) for securely generating and verifying authentication codes. The each agent’s data are encrypted by a pseudo-chaos cipher mechanism which doesn’t need any floating processing co-processor. We’ve constructed a prototype system on a Java mobile agent framework, “Bee-gent" which implements the proposed authentication and cipher mechanisms, and evaluated their performances and their applicability to business fields such as an auction system by mobile agents.

  8. 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. PMID:25000368

  9. 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

  10. Optimal Software Strategies in the Presence of Network Externalities

    ERIC Educational Resources Information Center

    Liu, Yipeng

    2009-01-01

    Network externalities or alternatively termed network effects are pervasive in computer software markets. While software vendors consider pricing strategies, they must also take into account the impact of network externalities on their sales. My main interest in this research is to describe a firm's strategies and behaviors in the presence of…

  11. Internal Capabilities, External Network Position, and Knowledge Creation

    ERIC Educational Resources Information Center

    Liao, Yin-Chi

    2010-01-01

    Despite the general consensus on the importance of interfirm networks, there is an ongoing debate centering on which type of network structure is most beneficial to firm performance. While spanning structural holes--a network position with disconnected partners--is argued to be advantageous in terms of providing access to diverse knowledge,…

  12. Evaluation of transmission network capacity use for wheeling transactions

    SciTech Connect

    Shirmohammadi, D.; Gribik, P.R.; Law, E.T.K.; Malinowski, J.H.; O'Donnell, R.E. )

    1989-11-01

    This paper describes the principles and the implementation of a methodology to evaluate the transmission network capacity use for firm transmission services including wheeling transactions. In this methodology transmission network capacity use for a transaction is a function of the magnitude of electric power, the length of the transmission lines and the type of facilities involved in the transaction. This capacity value provides an equitable means of allocating the cost of transmission facilities among users of the firm transmission service.

  13. Neural Networks

    SciTech Connect

    Smith, Patrick I.

    2003-09-23

    Physicists use large detectors to measure particles created in high-energy collisions at particle accelerators. These detectors typically produce signals indicating either where ionization occurs along the path of the particle, or where energy is deposited by the particle. The data produced by these signals is fed into pattern recognition programs to try to identify what particles were produced, and to measure the energy and direction of these particles. Ideally, there are many techniques used in this pattern recognition software. One technique, neural networks, is particularly suitable for identifying what type of particle caused by a set of energy deposits. Neural networks can derive meaning from complicated or imprecise data, extract patterns, and detect trends that are too complex to be noticed by either humans or other computer related processes. To assist in the advancement of this technology, Physicists use a tool kit to experiment with several neural network techniques. The goal of this research is interface a neural network tool kit into Java Analysis Studio (JAS3), an application that allows data to be analyzed from any experiment. As the final result, a physicist will have the ability to train, test, and implement a neural network with the desired output while using JAS3 to analyze the results or output. Before an implementation of a neural network can take place, a firm understanding of what a neural network is and how it works is beneficial. A neural network is an artificial representation of the human brain that tries to simulate the learning process [5]. It is also important to think of the word artificial in that definition as computer programs that use calculations during the learning process. In short, a neural network learns by representative examples. Perhaps the easiest way to describe the way neural networks learn is to explain how the human brain functions. The human brain contains billions of neural cells that are responsible for processing

  14. 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. PMID:12284511

  15. 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.

  16. Hypercompetitive Environments: An Agent-based model approach

    NASA Astrophysics Data System (ADS)

    Dias, Manuel; Araújo, Tanya

    Information technology (IT) environments are characterized by complex changes and rapid evolution. Globalization and the spread of technological innovation have increased the need for new strategic information resources, both from individual firms and management environments. Improvements in multidisciplinary methods and, particularly, the availability of powerful computational tools, are giving researchers an increasing opportunity to investigate management environments in their true complex nature. The adoption of a complex systems approach allows for modeling business strategies from a bottom-up perspective — understood as resulting from repeated and local interaction of economic agents — without disregarding the consequences of the business strategies themselves to individual behavior of enterprises, emergence of interaction patterns between firms and management environments. Agent-based models are at the leading approach of this attempt.

  17. 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.

  18. Spacecraft sanitation agent development

    NASA Technical Reports Server (NTRS)

    1972-01-01

    The development of an effective sanitizing agent that is compatible with the spacecraft environment and the human occupant is discussed. Experimental results show that two sanitation agents must be used to satisfy mission requirements: one agent for personal hygiene and one for equipment maintenance. It was also recommended that a water rinse be used with the agents for best results, and that consideration be given to using the agents pressure packed or in aerosol formulations.

  19. Beyond business process redesign: redefining Baxter's business network.

    PubMed

    Short, J E; Venkatraman, N

    1992-01-01

    Business process redesign has focused almost exclusively on improving the firm's internal operations. Although internal efficiency and effectiveness are important objectives, the authors argue that business network redesign--reconceptualizing the role of the firm and its key business processes in the larger business network--is of greater strategic importance. To support their argument, they analyze the evolution of Baxter's ASAP system, one of the most publicized but inadequately understood strategic information systems of the 1980s. They conclude by examining whether ASAP's early successes have positioned the firm well for the changing hospital supplies marketplace of the 1990s. PMID:10122293

  20. Trust method for multi-agent consensus

    NASA Astrophysics Data System (ADS)

    Mikulski, Dariusz G.; Lewis, Frank L.; Gu, Edward Y.; Hudas, Greg R.

    2012-06-01

    The consensus problem in multi-agent systems often assumes that all agents are equally trustworthy to seek agreement. But for multi-agent military applications - particularly those that deal with sensor fusion or multi-robot formation control - this assumption may create the potential for compromised network security or poor cooperative performance. As such, we present a trust-based solution for the discrete-time multi-agent consensus problem and prove its asymptotic convergence in strongly connected digraphs. The novelty of the paper is a new trust algorithm called RoboTrust, which is used to calculate trustworthiness in agents using observations and statistical inferences from various historical perspectives. The performance of RoboTrust is evaluated within the trust-based consensus protocol under different conditions of tolerance and confirmation.

  1. 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. PMID:21806296

  2. 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. PMID:18020790

  3. 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

  4. 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.

  5. Celestial data routing network

    NASA Astrophysics Data System (ADS)

    Bordetsky, Alex

    2000-11-01

    Imagine that information processing human-machine network is threatened in a particular part of the world. Suppose that an anticipated threat of physical attacks could lead to disruption of telecommunications network management infrastructure and access capabilities for small geographically distributed groups engaged in collaborative operations. Suppose that small group of astronauts are exploring the solar planet and need to quickly configure orbital information network to support their collaborative work and local communications. The critical need in both scenarios would be a set of low-cost means of small team celestial networking. To the geographically distributed mobile collaborating groups such means would allow to maintain collaborative multipoint work, set up orbital local area network, and provide orbital intranet communications. This would be accomplished by dynamically assembling the network enabling infrastructure of the small satellite based router, satellite based Codec, and set of satellite based intelligent management agents. Cooperating single function pico satellites, acting as agents and personal switching devices together would represent self-organizing intelligent orbital network of cooperating mobile management nodes. Cooperative behavior of the pico satellite based agents would be achieved by comprising a small orbital artificial neural network capable of learning and restructing the networking resources in response to the anticipated threat.

  6. The Community Structure of the Global Corporate Network

    PubMed Central

    Vitali, Stefania; Battiston, Stefano

    2014-01-01

    We investigate the community structure of the global ownership network of transnational corporations. We find a pronounced organization in communities that cannot be explained by randomness. Despite the global character of this network, communities reflect first of all the geographical location of firms, while the industrial sector plays only a marginal role. We also analyze the meta-network in which the nodes are the communities and the links are obtained by aggregating the links among firms belonging to pairs of communities. We analyze the network centrality of the top 50 communities and we provide a quantitative assessment of the financial sector role in connecting the global economy. PMID:25126722

  7. The community structure of the global corporate network.

    PubMed

    Vitali, Stefania; Battiston, Stefano

    2014-01-01

    We investigate the community structure of the global ownership network of transnational corporations. We find a pronounced organization in communities that cannot be explained by randomness. Despite the global character of this network, communities reflect first of all the geographical location of firms, while the industrial sector plays only a marginal role. We also analyze the meta-network in which the nodes are the communities and the links are obtained by aggregating the links among firms belonging to pairs of communities. We analyze the network centrality of the top 50 communities and we provide a quantitative assessment of the financial sector role in connecting the global economy. PMID:25126722

  8. 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

  9. The Impact of Intrapreneurial Programs on Fortune 500 Manufacturing Firms.

    ERIC Educational Resources Information Center

    Marcus, Melissa H.; Tesolowski, Dennis G.; Isbell, Clinton H.

    2000-01-01

    A survey of 100 manufacturing firms in 10 Standard Industrial Classification areas found that intrapreneurial programs did not significantly affect sales, profits, or returns to investors. Electronics and computer companies and the most dominant intrapreneurial programs. (SK)

  10. Zipf distribution in top Chinese firms and an economic explanation

    NASA Astrophysics Data System (ADS)

    Zhang, Jianhua; Chen, Qinghua; Wang, Yougui

    2009-05-01

    By analyzing the data of top 500 Chinese firms from the year 2002 to 2007, we reveal that their revenues and ranks obey the Zipf’s law with exponent of 1 for each year. This result confirms the universality of firm size character which has been presented in many other empirical works, since China possesses a unique ideological and political system. We offer an explanation of it based on a simple economic model which takes production and capital accumulation into account.

  11. Automated experimentation in ecological networks

    PubMed Central

    2011-01-01

    Background In ecological networks, natural communities are studied from a complex systems perspective by representing interactions among species within them in the form of a graph, which is in turn analysed using mathematical tools. Topological features encountered in complex networks have been proved to provide the systems they represent with interesting attributes such as robustness and stability, which in ecological systems translates into the ability of communities to resist perturbations of different kinds. A focus of research in community ecology is on understanding the mechanisms by which these complex networks of interactions among species in a community arise. We employ an agent-based approach to model ecological processes operating at the species' interaction level for the study of the emergence of organisation in ecological networks. Results We have designed protocols of interaction among agents in a multi-agent system based on ecological processes occurring at the interaction level between species in plant-animal mutualistic communities. Interaction models for agents coordination thus engineered facilitate the emergence of network features such as those found in ecological networks of interacting species, in our artificial societies of agents. Conclusions Agent based models developed in this way facilitate the automation of the design an execution of simulation experiments that allow for the exploration of diverse behavioural mechanisms believed to be responsible for community organisation in ecological communities. This automated way of conducting experiments empowers the study of ecological networks by exploiting the expressive power of interaction models specification in agent systems. PMID:21554669

  12. The induction of synaesthesia with chemical agents: a systematic review

    PubMed Central

    Luke, David P.; Terhune, Devin B.

    2013-01-01

    Despite the general consensus that synaesthesia emerges at an early developmental stage and is only rarely acquired during adulthood, the transient induction of synaesthesia with chemical agents has been frequently reported in research on different psychoactive substances. Nevertheless, these effects remain poorly understood and have not been systematically incorporated. Here we review the known published studies in which chemical agents were observed to elicit synaesthesia. Across studies there is consistent evidence that serotonin agonists elicit transient experiences of synaesthesia. Despite convergent results across studies, studies investigating the induction of synaesthesia with chemical agents have numerous methodological limitations and little experimental research has been conducted. Cumulatively, these studies implicate the serotonergic system in synaesthesia and have implications for the neurochemical mechanisms underlying this phenomenon but methodological limitations in this research area preclude making firm conclusions regarding whether chemical agents can induce genuine synaesthesia. PMID:24146659

  13. 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.

  14. Competitive dynamics on complex networks.

    PubMed

    Zhao, Jiuhua; Liu, Qipeng; Wang, Xiaofan

    2014-01-01

    We consider a dynamical network model in which two competitors have fixed and different states, and each normal agent adjusts its state according to a distributed consensus protocol. The state of each normal agent converges to a steady value which is a convex combination of the competitors' states, and is independent of the initial states of agents. This implies that the competition result is fully determined by the network structure and positions of competitors in the network. We compute an Influence Matrix (IM) in which each element characterizing the influence of an agent on another agent in the network. We use the IM to predict the bias of each normal agent and thus predict which competitor will win. Furthermore, we compare the IM criterion with seven node centrality measures to predict the winner. We find that the competitor with higher Katz Centrality in an undirected network or higher PageRank in a directed network is most likely to be the winner. These findings may shed new light on the role of network structure in competition and to what extent could competitors adjust network structure so as to win the competition. PMID:25068622

  15. Competitive Dynamics on Complex Networks

    NASA Astrophysics Data System (ADS)

    Zhao, Jiuhua; Liu, Qipeng; Wang, Xiaofan

    2014-07-01

    We consider a dynamical network model in which two competitors have fixed and different states, and each normal agent adjusts its state according to a distributed consensus protocol. The state of each normal agent converges to a steady value which is a convex combination of the competitors' states, and is independent of the initial states of agents. This implies that the competition result is fully determined by the network structure and positions of competitors in the network. We compute an Influence Matrix (IM) in which each element characterizing the influence of an agent on another agent in the network. We use the IM to predict the bias of each normal agent and thus predict which competitor will win. Furthermore, we compare the IM criterion with seven node centrality measures to predict the winner. We find that the competitor with higher Katz Centrality in an undirected network or higher PageRank in a directed network is most likely to be the winner. These findings may shed new light on the role of network structure in competition and to what extent could competitors adjust network structure so as to win the competition.

  16. Hydroxypyridonate chelating agents

    DOEpatents

    Raymond, Kenneth N.; Scarrow, Robert C.; White, David L.

    1987-01-01

    Chelating agents having 1-hydroxy-2-pyridinone (HOPO) and related moieties incorporated within their structures, including polydentate HOPO-substituted polyamines such as spermidine and spermine, and HOPO-substituted desferrioxamine. The chelating agents are useful in selectively removing certain cations from solution, and are particularly useful as ferric ion and actinide chelators. Novel syntheses of the chelating agents are provided.

  17. Mobile Agents Applications.

    ERIC Educational Resources Information Center

    Martins, Rosane Maria; Chaves, Magali Ribeiro; Pirmez, Luci; Rust da Costa Carmo, Luiz Fernando

    2001-01-01

    Discussion of the need to filter and retrieval relevant information from the Internet focuses on the use of mobile agents, specific software components which are based on distributed artificial intelligence and integrated systems. Surveys agent technology and discusses the agent building package used to develop two applications using IBM's Aglet…

  18. Performance in quasi-firms: an example from the Community Clinical Oncology Program.

    PubMed

    Lacey, L M; Hynes, D M; Kaluzny, A D

    1992-01-01

    In this analysis, the authors examined the effects of different sets of process, structure, and environmental variables on the performance of the CCOP as a quasi-firm. Specifically, they distinguished between internal organizational processes, structural, and size characteristics of the CCOP and the organizational environment created by prior NCI program experience and the relationship within the quasi-firm. The analysis revealed that these sets of organizational and environmental characteristics have differential effects on treatment accrual. The strongest predictors are those associated with the quasi-firm relationship between the CCOP and its chosen research bases. Any definitive policy implications for the design of organizational network relationships--especially the CCOPs--will require further analysis. Particular attention needs to be given to the longitudinal nature of the relationships and the ability of these organizational and environmental factors to affect other aspects of performance. Several points have been made within this initial assessment. First, the structural character of the CCOP and its relationship to its organizational environment are important factors affecting accrual performance. The subtleties of this multivariate model are not as important as simply demonstrating that the various internal and external characteristics of these organizations as quasi-firms simultaneously affect their ability to accrue patients to clinical trials. Secondly, the importance of research base relations, and particularly the significant role of nurses, needs to be emphasized. While CCOPs were originally designed as a network of physicians and hospitals, it appears that an infrastructure of professionally active nurses working within a larger organizational environment is critical to success--at least as defined by accrual to treatment protocols. Finally, the failure of prior experience with other NCI community programs to affect CCOP accrual performance

  19. Standard Agent Framework 1

    SciTech Connect

    Goldsmith, Steven Y.

    1999-04-06

    The Standard Agent framework provides an extensible object-oriented development environment suitable for use in both research and applications projects. The SAF provides a means for constructing and customizing multi-agent systems through specialization of standard base classes (architecture-driven framework) and by composition of component classes (data driven framework). The standard agent system is implemented as an extensible object-centerd framework. Four concrete base classes are developed: (1) Standard Agency; (2) Standard Agent; (3) Human Factor, and (4) Resources. The object-centered framework developed and utilized provides the best comprimise between generality and flexibility available in agent development systems today.

  20. 48 CFR 519.7008 - Selection of protégé firms.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... SOCIOECONOMIC PROGRAMS SMALL BUSINESS PROGRAMS GSA Mentor-Protégé Program 519.7008 Selection of protégé firms. (a) Mentor firms will be solely responsible for selecting protégé firms. Mentors are encouraged to... subcontractor or a newly selected subcontractor for the prime contractor's GSA contract. (b) Mentor firms...

  1. 48 CFR 519.7008 - Selection of protégé firms.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... SOCIOECONOMIC PROGRAMS SMALL BUSINESS PROGRAMS GSA Mentor-Protégé Program 519.7008 Selection of protégé firms. (a) Mentor firms will be solely responsible for selecting protégé firms. Mentors are encouraged to... subcontractor or a newly selected subcontractor for the prime contractor's GSA contract. (b) Mentor firms...

  2. 48 CFR 519.7008 - Selection of protégé firms.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... SOCIOECONOMIC PROGRAMS SMALL BUSINESS PROGRAMS GSA Mentor-Protégé Program 519.7008 Selection of protégé firms. (a) Mentor firms will be solely responsible for selecting protégé firms. Mentors are encouraged to... subcontractor or a newly selected subcontractor for the prime contractor's GSA contract. (b) Mentor firms...

  3. 48 CFR 519.7008 - Selection of protégé firms.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... SOCIOECONOMIC PROGRAMS SMALL BUSINESS PROGRAMS GSA Mentor-Protégé Program 519.7008 Selection of protégé firms. (a) Mentor firms will be solely responsible for selecting protégé firms. Mentors are encouraged to... subcontractor or a newly selected subcontractor for the prime contractor's GSA contract. (b) Mentor firms...

  4. 48 CFR 519.7008 - Selection of protégé firms.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... SOCIOECONOMIC PROGRAMS SMALL BUSINESS PROGRAMS GSA Mentor-Protégé Program 519.7008 Selection of protégé firms. (a) Mentor firms will be solely responsible for selecting protégé firms. Mentors are encouraged to... subcontractor or a newly selected subcontractor for the prime contractor's GSA contract. (b) Mentor firms...

  5. 75 FR 2491 - Trade Adjustment Assistance for Firms Program Fiscal Year 2009 Annual Report

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-15

    ...-sized firms in FY 2009. The average employment, net sales, and productivity of firms certified in FY.... annual net productivity at FY at sales at certification certification certification (net sales per... of firms leaving the program and why, and (4) sales, employment, and productivity at each firm...

  6. Self-organising disturbance attenuation for synchronised agents with individual dynamics

    NASA Astrophysics Data System (ADS)

    Lunze, Jan

    2015-03-01

    This paper proposes a self-organising networked controller for disturbance attenuation in multi-agent systems. A disturbance affecting a single agent has some effect on all neighbouring agents through the communication network. To avoid large disturbance effects, the proposed self-organising controller switches off the communication whenever the effect of the disturbance on the corresponding agent exceeds a given bound. As a consequence, the structure of the networked controller is adjusted to the current disturbance. It is proved that the proposed controller bounds the effect of any disturbance on all undisturbed agents. The results are illustrated by their application to a robot formation problem.

  7. Resource-efficient wireless monitoring based on mobile agent migration

    NASA Astrophysics Data System (ADS)

    Smarsly, Kay; Law, Kincho H.; König, Markus

    2011-04-01

    Wireless sensor networks are increasingly adopted in many engineering applications such as environmental and structural monitoring. Having proven to be low-cost, easy to install and accurate, wireless sensor networks serve as a powerful alternative to traditional tethered monitoring systems. However, due to the limited resources of a wireless sensor node, critical problems are the power-consuming transmission of the collected sensor data and the usage of onboard memory of the sensor nodes. This paper presents a new approach towards resource-efficient wireless sensor networks based on a multi-agent paradigm. In order to efficiently use the restricted computing resources, software agents are embedded in the wireless sensor nodes. On-board agents are designed to autonomously collect, analyze and condense the data sets using relatively simple yet resource-efficient algorithms. If having detected (potential) anomalies in the observed structural system, the on-board agents explicitly request specialized software agents. These specialized agents physically migrate from connected computer systems, or adjacent nodes, to the respective sensor node in order to perform more complex damage detection analyses based on their inherent expert knowledge. A prototype system is designed and implemented, deploying multi-agent technology and dynamic code migration, in a wireless sensor network for structural health monitoring. Laboratory tests are conducted to validate the performance of the agent-based wireless structural health monitoring system and to verify its autonomous damage detection capabilities.

  8. Multiscale agent-based consumer market modeling.

    SciTech Connect

    North, M. J.; Macal, C. M.; St. Aubin, J.; Thimmapuram, P.; Bragen, M.; Hahn, J.; Karr, J.; Brigham, N.; Lacy, M. E.; Hampton, D.; Decision and Information Sciences; Procter & Gamble Co.

    2010-05-01

    Consumer markets have been studied in great depth, and many techniques have been used to represent them. These have included regression-based models, logit models, and theoretical market-level models, such as the NBD-Dirichlet approach. Although many important contributions and insights have resulted from studies that relied on these models, there is still a need for a model that could more holistically represent the interdependencies of the decisions made by consumers, retailers, and manufacturers. When the need is for a model that could be used repeatedly over time to support decisions in an industrial setting, it is particularly critical. Although some existing methods can, in principle, represent such complex interdependencies, their capabilities might be outstripped if they had to be used for industrial applications, because of the details this type of modeling requires. However, a complementary method - agent-based modeling - shows promise for addressing these issues. Agent-based models use business-driven rules for individuals (e.g., individual consumer rules for buying items, individual retailer rules for stocking items, or individual firm rules for advertizing items) to determine holistic, system-level outcomes (e.g., to determine if brand X's market share is increasing). We applied agent-based modeling to develop a multi-scale consumer market model. We then conducted calibration, verification, and validation tests of this model. The model was successfully applied by Procter & Gamble to several challenging business problems. In these situations, it directly influenced managerial decision making and produced substantial cost savings.

  9. The Strategic Partners Network's Extraction: The XStrat.Net Project

    NASA Astrophysics Data System (ADS)

    Taifi, Nouha; Passiante, Giuseppina

    The firms in the business environment have to choose adequate partners in order to sustain their competitive advantage and their economic performance. Plus, the creation of special communities consisting of these partners is essential for the life-long development of these latter and the firms creating them. The research project XStrat.Net aims at the identification of factors and indicators about the organizations for the modelling of intelligent agents -XStrat intelligent agents- and the engineering of a software -XStrat- to process these backbones intelligent agents. Through the use of the software, the firms will be able to select the needed partners for the creation of special communities for the purpose of learning, interest or innovation. The XStrat.Net project also intends to provide guidelines for the creation of the special communities.

  10. 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.

  11. Environmental management intentions: an empirical investigation of Argentina's polluting firms.

    PubMed

    Vazquez Brust, Diego Alfonso; Liston-Heyes, Catherine

    2010-05-01

    This paper builds on past behavioural research which explicitly recognises that 'actions' are preceded by 'intentions' which are in turn determined by individual mindsets, locus of control, principles of governances and context factors. More concretely, it presents a model that investigates the extent to which environmental behavioural intentions are explained by i) managers' core values, basic assumptions, and beliefs, ii) individual and socio-cognitive frames, iii) principles of governance, and iv) context factors. Context factors include obstacles and drivers of greener behaviours, market pressures, and firm demographics. The resulting theoretical framework is tested empirically through regression analyses that use data gathered from a survey of 536 Argentinean firms in polluting industries. The model performs well, explaining approximately 50% of the variations in the (pro) environmental behaviour of firms. Policy implications are briefly discussed. PMID:20110148

  12. Agent Architectures for Compliance

    NASA Astrophysics Data System (ADS)

    Burgemeestre, Brigitte; Hulstijn, Joris; Tan, Yao-Hua

    A Normative Multi-Agent System consists of autonomous agents who must comply with social norms. Different kinds of norms make different assumptions about the cognitive architecture of the agents. For example, a principle-based norm assumes that agents can reflect upon the consequences of their actions; a rule-based formulation only assumes that agents can avoid violations. In this paper we present several cognitive agent architectures for self-monitoring and compliance. We show how different assumptions about the cognitive architecture lead to different information needs when assessing compliance. The approach is validated with a case study of horizontal monitoring, an approach to corporate tax auditing recently introduced by the Dutch Customs and Tax Authority.

  13. 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.

  14. Chemical crowd control agents.

    PubMed

    Menezes, Ritesh G; Hussain, Syed Ather; Rameez, Mansoor Ali Merchant; Kharoshah, Magdy A; Madadin, Mohammed; Anwar, Naureen; Senthilkumaran, Subramanian

    2016-03-01

    Chemical crowd control agents are also referred to as riot control agents and are mainly used by civil authorities and government agencies to curtail civil disobedience gatherings or processions by large crowds. Common riot control agents used to disperse large numbers of individuals into smaller, less destructive, and more easily controllable numbers include chloroacetophenone, chlorobenzylidenemalononitrile, dibenzoxazepine, diphenylaminearsine, and oleoresin capsicum. In this paper, we discuss the emergency medical care needed by sufferers of acute chemical agent contamination and raise important issues concerning toxicology, safety and health. PMID:26658556

  15. 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.

  16. 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.

  17. Flocking of multi-agent systems with multiple groups

    NASA Astrophysics Data System (ADS)

    Jing, Gangshan; Zheng, Yuanshi; Wang, Long

    2014-12-01

    In this paper, we consider the flocking problem of multi-agent systems with multiple groups. First, some algorithms using local information are designed to divide the agents into any pre-assigned number of groups in fixed and switching heterogeneous networks, respectively. Based on algebraic graph theory and Barbalat's lemma, convergence criteria are established to ensure velocity alignment and cohesion of each subgroup as well as collision avoidance between any agents in the whole group. Second, an algorithm for homogeneous networks is studied. Simulation examples are finally presented to verify the effectiveness of our theoretical results.

  18. Who's your neighbor? neighbor identification for agent-based modeling.

    SciTech Connect

    Macal, C. M.; Howe, T. R.; Decision and Information Sciences; Univ. of Chicago

    2006-01-01

    Agent-based modeling and simulation, based on the cellular automata paradigm, is an approach to modeling complex systems comprised of interacting autonomous agents. Open questions in agent-based simulation focus on scale-up issues encountered in simulating large numbers of agents. Specifically, how many agents can be included in a workable agent-based simulation? One of the basic tenets of agent-based modeling and simulation is that agents only interact and exchange locally available information with other agents located in their immediate proximity or neighborhood of the space in which the agents are situated. Generally, an agent's set of neighbors changes rapidly as a simulation proceeds through time and as the agents move through space. Depending on the topology defined for agent interactions, proximity may be defined by spatial distance for continuous space, adjacency for grid cells (as in cellular automata), or by connectivity in social networks. Identifying an agent's neighbors is a particularly time-consuming computational task and can dominate the computational effort in a simulation. Two challenges in agent simulation are (1) efficiently representing an agent's neighborhood and the neighbors in it and (2) efficiently identifying an agent's neighbors at any time in the simulation. These problems are addressed differently for different agent interaction topologies. While efficient approaches have been identified for agent neighborhood representation and neighbor identification for agents on a lattice with general neighborhood configurations, other techniques must be used when agents are able to move freely in space. Techniques for the analysis and representation of spatial data are applicable to the agent neighbor identification problem. This paper extends agent neighborhood simulation techniques from the lattice topology to continuous space, specifically R2. Algorithms based on hierarchical (quad trees) or non-hierarchical data structures (grid cells) are

  19. Agents, Bayes, and Climatic Risks - a modular modelling approach

    NASA Astrophysics Data System (ADS)

    Haas, A.; Jaeger, C.

    2005-08-01

    When insurance firms, energy companies, governments, NGOs, and other agents strive to manage climatic risks, it is by no way clear what the aggregate outcome should and will be. As a framework for investigating this subject, we present the LAGOM model family. It is based on modules depicting learning social agents. For managing climate risks, our agents use second order probabilities and update them by means of a Bayesian mechanism while differing in priors and risk aversion. The interactions between these modules and the aggregate outcomes of their actions are implemented using further modules. The software system is implemented as a series of parallel processes using the CIAMn approach. It is possible to couple modules irrespective of the language they are written in, the operating system under which they are run, and the physical location of the machine.

  20. Social Networking Sites as a Learning Tool

    ERIC Educational Resources Information Center

    Sanchez-Casado, Noelia; Cegarra Navarro, Juan Gabriel; Wensley, Anthony; Tomaseti-Solano, Eva

    2016-01-01

    Purpose: Over the past few years, social networking sites (SNSs) have become very useful for firms, allowing companies to manage the customer-brand relationships. In this context, SNSs can be considered as a learning tool because of the brand knowledge that customers develop from these relationships. Because of the fact that knowledge in…

  1. Intelligent Software Agents: Sensor Integration and Response

    SciTech Connect

    Kulesz, James J; Lee, Ronald W

    2013-01-01

    Abstract In a post Macondo world the buzzwords are Integrity Management and Incident Response Management. The twin processes are not new but the opportunity to link the two is novel. Intelligent software agents can be used with sensor networks in distributed and centralized computing systems to enhance real-time monitoring of system integrity as well as manage the follow-on incident response to changing, and potentially hazardous, environmental conditions. The software components are embedded at the sensor network nodes in surveillance systems used for monitoring unusual events. When an event occurs, the software agents establish a new concept of operation at the sensing node, post the event status to a blackboard for software agents at other nodes to see , and then react quickly and efficiently to monitor the scale of the event. The technology addresses a current challenge in sensor networks that prevents a rapid and efficient response when a sensor measurement indicates that an event has occurred. By using intelligent software agents - which can be stationary or mobile, interact socially, and adapt to changing situations - the technology offers features that are particularly important when systems need to adapt to active circumstances. For example, when a release is detected, the local software agent collaborates with other agents at the node to exercise the appropriate operation, such as: targeted detection, increased detection frequency, decreased detection frequency for other non-alarming sensors, and determination of environmental conditions so that adjacent nodes can be informed that an event is occurring and when it will arrive. The software agents at the nodes can also post the data in a targeted manner, so that agents at other nodes and the command center can exercise appropriate operations to recalibrate the overall sensor network and associated intelligence systems. The paper describes the concepts and provides examples of real-world implementations

  2. Structurally Dynamic Spin Market Networks

    NASA Astrophysics Data System (ADS)

    Horváth, Denis; Kuscsik, Zoltán

    The agent-based model of stock price dynamics on a directed evolving complex network is suggested and studied by direct simulation. The stationary regime is maintained as a result of the balance between the extremal dynamics, adaptivity of strategic variables and reconnection rules. The inherent structure of node agent "brain" is modeled by a recursive neural network with local and global inputs and feedback connections. For specific parametric combination the complex network displays small-world phenomenon combined with scale-free behavior. The identification of a local leader (network hub, agent whose strategies are frequently adapted by its neighbors) is carried out by repeated random walk process through network. The simulations show empirically relevant dynamics of price returns and volatility clustering. The additional emerging aspects of stylized market statistics are Zipfian distributions of fitness.

  3. Determinants of Network News Coverage of the Oil Industry during the Late 1970s.

    ERIC Educational Resources Information Center

    Erfle, Stephen; McMillan, Henry

    1989-01-01

    Examines which firms and products best predict media coverage of the oil industry. Reports that price variations in testing oil and gasoline correlate with the extent of news coverage provided by network television. (MM)

  4. Immunization of complex networks

    NASA Astrophysics Data System (ADS)

    Pastor-Satorras, Romualdo; Vespignani, Alessandro

    2002-03-01

    Complex networks such as the sexual partnership web or the Internet often show a high degree of redundancy and heterogeneity in their connectivity properties. This peculiar connectivity provides an ideal environment for the spreading of infective agents. Here we show that the random uniform immunization of individuals does not lead to the eradication of infections in all complex networks. Namely, networks with scale-free properties do not acquire global immunity from major epidemic outbreaks even in the presence of unrealistically high densities of randomly immunized individuals. The absence of any critical immunization threshold is due to the unbounded connectivity fluctuations of scale-free networks. Successful immunization strategies can be developed only by taking into account the inhomogeneous connectivity properties of scale-free networks. In particular, targeted immunization schemes, based on the nodes' connectivity hierarchy, sharply lower the network's vulnerability to epidemic attacks.

  5. Change Agent Survival Guide

    ERIC Educational Resources Information Center

    Dunbar, Folwell L.

    2011-01-01

    Consulting is a rough racket. Only a tarantula hair above IRS agents, meter maids and used car sales people, the profession is a prickly burr for slings and arrows. Throw in education, focus on dysfunctional schools and call oneself a "change agent," and this bad rap all but disappears. Unfortunately, though, consulting/coaching/mentoring in…

  6. Travel Agent Course Outline.

    ERIC Educational Resources Information Center

    British Columbia Dept. of Education, Victoria.

    Written for college entry-level travel agent training courses, this course outline can also be used for inservice training programs offered by travel agencies. The outline provides information on the work of a travel agent and gives clear statements on what learners must be able to do by the end of their training. Material is divided into eight…

  7. A centralized quantum switch network based on probabilistic channels

    NASA Astrophysics Data System (ADS)

    Jiang, Min; Wu, Re-Bing; Li, Hui; Zhang, Zeng-ke

    2013-01-01

    We present a practical scheme for deterministically teleporting quantum information via probabilistic communication channels in a centralized quantum switch network. In the network, a central quantum switch agent is assigned for regulating probabilistic channels so as to construct a direct deterministic channel between the sender and the receiver. This scheme is further extended to a hierarchical network and a tree network involving multiple agents. The advantage of the scheme is that all required multi qubit gates from distributed terminal agents are uniformly performed by a central agent, with which the physical design of terminal nodes is greatly simplified and more reliable deterministic teleportation can be realized in a centralized quantum probabilistic network.

  8. Towards a Swedish health policy for the 1990s: planned markets and public firms.

    PubMed

    von Otter, C; Saltman, R B

    1991-01-01

    The Swedish health system has entered a period of major structural transformation. Most county councils have begun to experiment with new service delivery mechanisms, and the governing Social Democratic Party has proposed wide-ranging reforms intended to improve the efficiency, quality, and responsiveness of all public human services. This paper draws upon key elements in the current Swedish debate to develop an alternative policy model for publicly operated health systems in general. We argue that the limitations of existing planning and market based policy models can be overcome by an approach constructed upon 'planned markets'. This alternative model involves restructuring publicly operated systems into an intentionally designed network of 'public firms' that engage in a socially as well as economically efficient process of 'public competition'. The model harnesses patient choice of provider as the driving mechanism to enhance both production efficiency and democratic participation within the Swedish health system. PMID:2024163

  9. Output regulation of switched linear multi-agent systems: an agent-dependent average dwell time method

    NASA Astrophysics Data System (ADS)

    Jia, Hongwei; Zhao, Jun

    2016-08-01

    The output regulation problem of switched linear multi-agent systems with stabilisable and unstabilisable subsystems is investigated in this paper. A sufficient condition for the solvability of the problem is given. Owing to the characteristics of switched multi-agent systems, even if each agent has its own dwell time, the multi-agent systems, if viewed as an overall switched system, may not have a dwell time. To overcome this difficulty, we present a new approach, called an agent-dependent average dwell time method. Due to the limited information exchange between agents, a distributed dynamic observer network for agents is provided. Further, a distributed dynamic controller based on observer is designed. Finally, simulation results show the effectiveness of the proposed solutions.

  10. Pediatric Antifungal Agents

    PubMed Central

    Cohen-Wolkowiez, Michael; Moran, Cassandra; Benjamin, Daniel K.; Smith, P Brian

    2009-01-01

    Purpose of review In immunocompromised hosts, invasive fungal infections are common and fatal. In the past decade, the antifungal armamentarium against invasive mycoses has expanded greatly. The purpose of this report is to review the most recent literature addressing the use of antifungal agents in children. Recent findings Most studies evaluating the safety and efficacy of antifungal agents are limited to adults. However, important progress has been made in describing the pharmacokinetics and safety of newer antifungal agents in children, including the echinocandins. Summary Dosage guidelines for newer antifungal agents are currently based on adult and limited pediatric data. Because important developmental pharmacology changes occur throughout childhood impacting the pharmacokinetics of these agents, antifungal studies specifically designed for children are necessary. PMID:19741525

  11. How do agents represent?

    NASA Astrophysics Data System (ADS)

    Ryan, Alex

    Representation is inherent to the concept of an agent, but its importance in complex systems has not yet been widely recognised. In this paper I introduce Peirce's theory of signs, which facilitates a definition of representation in general. In summary, representation means that for some agent, a model is used to stand in for another entity in a way that shapes the behaviour of the agent with respect to that entity. Representation in general is then related to the theories of representation that have developed within different disciplines. I compare theories of representation from metaphysics, military theory and systems theory. Additional complications arise in explaining the special case of mental representations, which is the focus of cognitive science. I consider the dominant theory of cognition — that the brain is a representational device — as well as the sceptical anti-representational response. Finally, I argue that representation distinguishes agents from non-representational objects: agents are objects capable of representation.

  12. Standard Agent Framework 1

    Energy Science and Technology Software Center (ESTSC)

    1999-04-06

    The Standard Agent framework provides an extensible object-oriented development environment suitable for use in both research and applications projects. The SAF provides a means for constructing and customizing multi-agent systems through specialization of standard base classes (architecture-driven framework) and by composition of component classes (data driven framework). The standard agent system is implemented as an extensible object-centerd framework. Four concrete base classes are developed: (1) Standard Agency; (2) Standard Agent; (3) Human Factor, and (4)more » Resources. The object-centered framework developed and utilized provides the best comprimise between generality and flexibility available in agent development systems today.« less

  13. Strategic HRM for SMEs: Implications for Firms and Policy

    ERIC Educational Resources Information Center

    Brand, Maryse J.; Bax, Erik H.

    2002-01-01

    This paper is on the growing importance of strategic human resource management (SHRM) for small and medium-sized enterprises (SMEs). Many small firms encounter serious human resource problems, while at the same time these human resources play a vital role in developing and sustaining their competitive advantages. In (S)HRM literature specific…

  14. Developing Small Firms in Local Communities. Circular CRD-24.

    ERIC Educational Resources Information Center

    Strawn, Harry B.

    Focusing on small, independent businesses, this primer answers questions relating to starting and operating a new firm and how local development organizations can help in the process. The general pattern of the company forming process (displacement, disposition to act, credibility, and availability of resources) is discussed. Success factors for…

  15. Maximize Benefits, Minimize Risk: Selecting the Right HVAC Firm.

    ERIC Educational Resources Information Center

    Golden, James T.

    1993-01-01

    An informal survey of 20 major urban school districts found that 40% were currently operating in a "break down" maintenance mode. A majority, 57.9%, also indicated they saw considerable benefits in contracting for heating, ventilating, and air conditioning (HVAC) maintenance services with outside firms. Offers guidelines in selecting HVAC…

  16. The Firm and Shaky Ground of Education for Sustainable Development

    ERIC Educational Resources Information Center

    Selby, David

    2006-01-01

    This paper employs academic and parable forms to evaluate critically the strengths and weaknesses, potentials and lacunae of education for sustainable development (ESD) and other sustainability-related educations. The meteoric rise to prominence of ESD is first briefly reviewed, as is the firm ground it now stands upon as an international and…

  17. 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 §...

  18. 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...

  19. 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...

  20. Teaching Evaluation: A Student-Run Consulting Firm

    ERIC Educational Resources Information Center

    Cundiff, Nicole; Nadler, Joel; Scribner, Shauna

    2011-01-01

    Applied Research Consultants (ARC) is a graduate student run consulting firm that provides experience to students in evaluation and consultation. An overview of this program has been compiled in order to serve as a model of a graduate training practicum that could be applied to similar programs or aid in the development of such programs. Key…

  1. Connecting Accounting and Communication: A Survey of Public Accounting Firms.

    ERIC Educational Resources Information Center

    Stowers, Robert H.; White, G. Thomas

    1999-01-01

    Reports on accounting professionals' self-assessment of their communication abilities (presentation, writing, interpersonal, and interviewing skills), factors contributing to these skills, and rankings of them. Shows that the development of effective communication skills, which are highly valued in public accounting firms, was not part of formal…

  2. 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…

  3. The Profit-Maximizing Firm: Old Wine in New Bottles.

    ERIC Educational Resources Information Center

    Felder, Joseph

    1990-01-01

    Explains and illustrates a simplified use of graphical analysis for analyzing the profit-maximizing firm. Believes that graphical analysis helps college students gain a deeper understanding of marginalism and an increased ability to formulate economic problems in marginalist terms. (DB)

  4. 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... concerning invention promoters and responses from the invention promoters to these complaints. An individual may submit a complaint concerning an invention promoter to the USPTO, which will forward the...

  5. Mathematical model of a utility firm. Executive summary

    SciTech Connect

    Not Available

    1983-08-21

    The project was aimed at developing an understanding of the economic and behavioral processes that take place within a utility firm, and without it. This executive summary, one of five documents, gives the project goals and objectives, outlines the subject areas of investigation, discusses the findings and results, and finally considers applications within the electric power industry and future research directions. (DLC)

  6. The Marketing Firm: Operant Interpretation of Corporate Behavior

    ERIC Educational Resources Information Center

    Vella, Kevin J.; Foxall, Gordon R.

    2013-01-01

    In this article we address the issue of applying operant psychology to derive plausible and useful interpretations of complex firm behavior in natural settings. The objective is to discuss an appropriate methodology based on case study design, developed specifically in Vella and Foxall (2011), to produce an operant interpretation of secondary…

  7. Blueberry Splitting Tendencies as Predicted by Fruit Firmness

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To improve the quality of berries during handling and shipping, blueberry breeders have strived to develop a fruit that is firm in texture. However previous studies show blueberry cultivars with firmer fruit were more susceptible to splitting. This study was further investigates the correlation be...

  8. 21 CFR 107.210 - Firm-initiated product removals.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... (CONTINUED) FOOD FOR HUMAN CONSUMPTION INFANT FORMULA Infant Formula Recalls § 107.210 Firm-initiated product removals. (a) If a manufacturer has determined to recall voluntarily from the market an infant formula that... prompt notification to FDA, shall administer such voluntary recall consistent with the requirements...

  9. 21 CFR 107.210 - Firm-initiated product removals.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... (CONTINUED) FOOD FOR HUMAN CONSUMPTION INFANT FORMULA Infant Formula Recalls § 107.210 Firm-initiated product removals. (a) If a manufacturer has determined to recall voluntarily from the market an infant formula that... prompt notification to FDA, shall administer such voluntary recall consistent with the requirements...

  10. 21 CFR 107.210 - Firm-initiated product removals.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... (CONTINUED) FOOD FOR HUMAN CONSUMPTION INFANT FORMULA Infant Formula Recalls § 107.210 Firm-initiated product removals. (a) If a manufacturer has determined to recall voluntarily from the market an infant formula that... prompt notification to FDA, shall administer such voluntary recall consistent with the requirements...

  11. 21 CFR 107.210 - Firm-initiated product removals.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... (CONTINUED) FOOD FOR HUMAN CONSUMPTION INFANT FORMULA Infant Formula Recalls § 107.210 Firm-initiated product removals. (a) If a manufacturer has determined to recall voluntarily from the market an infant formula that... prompt notification to FDA, shall administer such voluntary recall consistent with the requirements...

  12. Law Firm: A First-Year Course on Lawyering.

    ERIC Educational Resources Information Center

    Braveman, Daan

    1989-01-01

    An experimental first-year course introducing law students to the law firm addressed: a single issue in contract law from both sides, writing as an advocate, the lawyer's role, legal research methods, the legislative process, the counseling function, the appellate process, and traditional legal writing. An interdisciplinary approach was used. (MSE)

  13. 18 CFR 284.7 - Firm transportation service.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... Federal Register citations affecting § 284.7, see the List of CFR Sections Affected, which appears in the... 18 Conservation of Power and Water Resources 1 2012-04-01 2012-04-01 false Firm transportation... AUTHORITIES CERTAIN SALES AND TRANSPORTATION OF NATURAL GAS UNDER THE NATURAL GAS POLICY ACT OF 1978...

  14. 18 CFR 284.7 - Firm transportation service.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... Federal Register citations affecting § 284.7, see the List of CFR Sections Affected, which appears in the... 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...

  15. 18 CFR 284.7 - Firm transportation service.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... Federal Register citations affecting § 284.7, see the List of CFR Sections Affected, which appears in the... 18 Conservation of Power and Water Resources 1 2013-04-01 2013-04-01 false Firm transportation... AUTHORITIES CERTAIN SALES AND TRANSPORTATION OF NATURAL GAS UNDER THE NATURAL GAS POLICY ACT OF 1978...

  16. 18 CFR 284.7 - Firm transportation service.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... Federal Register citations affecting § 284.7, see the List of CFR Sections Affected, which appears in the... 18 Conservation of Power and Water Resources 1 2010-04-01 2010-04-01 false Firm transportation... AUTHORITIES CERTAIN SALES AND TRANSPORTATION OF NATURAL GAS UNDER THE NATURAL GAS POLICY ACT OF 1978...

  17. 18 CFR 284.7 - Firm transportation service.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... Federal Register citations affecting § 284.7, see the List of CFR Sections Affected, which appears in the... 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...

  18. Impulsive synchronization of networked nonlinear dynamical systems

    NASA Astrophysics Data System (ADS)

    Jiang, Haibo; Bi, Qinsheng

    2010-06-01

    In this Letter, we investigate the problem of impulsive synchronization of networked multi-agent systems, where each agent can be modeled as an identical nonlinear dynamical system. Firstly, an impulsive control protocol is designed for network with fixed topology based on the local information of agents. Then sufficient conditions are given to guarantee the synchronization of the networked nonlinear dynamical system by using algebraic graph theory and impulsive control theory. Furthermore, how to select the discrete instants and impulsive constants is discussed. The case that the topologies of the networks are switching is also considered. Numerical simulations show the effectiveness of our theoretical results.

  19. 78 FR 1264 - CalAmp Wireless Networks Corporation, Waseca, MN; Notice of Negative Determination Regarding...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-08

    ... Employment and Training Administration CalAmp Wireless Networks Corporation, Waseca, MN; Notice of Negative... workers of the subject firm (TA-W-80,399A; CalAmp Wireless Networks Corporation, Waseca, Minnesota... Wireless Networks Corporation, Waseca, Minnesota to apply for TAA, the Department determines that...

  20. Real Time Pricing and the Real Live Firm

    SciTech Connect

    Moezzi, Mithra; Goldman, Charles; Sezgen, Osman; Bharvirkar, Ranjit; Hopper, Nicole

    2004-05-26

    Energy economists have long argued the benefits of real time pricing (RTP) of electricity. Their basis for modeling customers response to short-term fluctuations in electricity prices are based on theories of rational firm behavior, where management strives to minimize operating costs and optimize profit, and labor, capital and energy are potential substitutes in the firm's production function. How well do private firms and public sector institutions operating conditions, knowledge structures, decision-making practices, and external relationships comport with these assumptions and how might this impact price response? We discuss these issues on the basis of interviews with 29 large (over 2 MW) industrial, commercial, and institutional customers in the Niagara Mohawk Power Corporation service territory that have faced day-ahead electricity market prices since 1998. We look at stories interviewees told about why and how they respond to RTP, why some customers report that they can't, and why even if they can, they don't. Some firms respond as theorized, and we describe their load curtailment strategies. About half of our interviewees reported that they were unable to either shift or forego electricity consumption even when prices are high ($0.50/kWh). Reasons customers gave for why they weren't price-responsive include implicit value placed on reliability, pricing structures, lack of flexibility in adjusting production inputs, just-in-time practices, perceived barriers to onsite generation, and insufficient time. We draw these observations into a framework that could help refine economic theory of dynamic pricing by providing real-world descriptions of how firms behave and why.

  1. Proxy-agent management platform for OXC managed objects

    NASA Astrophysics Data System (ADS)

    Pahk, Soomyung; Joo, Seong-Soon; Nam, Hyun-Soon; Lee, Sang-Wha; Kim, Hae G.

    2001-10-01

    In this paper, we present a Proxy-Agent Management Platform, which supports the managed objects of the Optical Cross-Connects (OXC). OXC is a sophisticated WDM network element (NE) that makes the WDM networks reconfigurable. It consists of several sub-NEs, such as 3R modules, Mux/Demux modules, transponder modules, optical switch fabric modules, and operation administration and maintenance processing modules. The OXC network element manager requests and gathers the managed information, alarms, and events from those sub-NEs in the OXC network element, and updates the Management Information Base (MIB) of the OXC managed object existed in the local or remote OXC network element management system. We propose an OXC network element manager with proxy-agent functions which could configure, control, and manage the sub-NEs via an unified access interface on the Common Object Request Broker Architecture (CORBA). The proxy-agent in the OXC network element management system offers its own MIB information to SNMP and/or CMIP manager. The proposed platform achieves high code reusability, provides unified access interfaces between sub-NEs and proxy-agent via ORB, and offers authentication and authorization. The proposed platform is verified on simulated testbed, and shows that managed objects can be added or droped easily to develop an intelligent OXC system.

  2. Biological warfare agents

    PubMed Central

    Thavaselvam, Duraipandian; Vijayaraghavan, Rajagopalan

    2010-01-01

    The recent bioterrorist attacks using anthrax spores have emphasized the need to detect and decontaminate critical facilities in the shortest possible time. There has been a remarkable progress in the detection, protection and decontamination of biological warfare agents as many instrumentation platforms and detection methodologies are developed and commissioned. Even then the threat of biological warfare agents and their use in bioterrorist attacks still remain a leading cause of global concern. Furthermore in the past decade there have been threats due to the emerging new diseases and also the re-emergence of old diseases and development of antimicrobial resistance and spread to new geographical regions. The preparedness against these agents need complete knowledge about the disease, better research and training facilities, diagnostic facilities and improved public health system. This review on the biological warfare agents will provide information on the biological warfare agents, their mode of transmission and spread and also the detection systems available to detect them. In addition the current information on the availability of commercially available and developing technologies against biological warfare agents has also been discussed. The risk that arise due to the use of these agents in warfare or bioterrorism related scenario can be mitigated with the availability of improved detection technologies. PMID:21829313

  3. Organizational Learning, Knowledge Management Practices and Firm's Performance: An Empirical Study of a Heavy Engineering Firm in India

    ERIC Educational Resources Information Center

    Jain, Ajay K.; Moreno, Ana

    2015-01-01

    Purpose: The study aims at investigating the impact of organizational learning (OL) on the firm's performance and knowledge management (KM) practices in a heavy engineering organization in India. Design/Methodology/Approach: The data were collected from 205 middle and senior executives working in the project engineering management division of a…

  4. The whole relationship between environmental variables and firm performance: competitive advantage and firm resources as mediator variables.

    PubMed

    López-Gamero, María D; Molina-Azorín, José F; Claver-Cortés, Enrique

    2009-07-01

    The examination of the possible direct link between environmental protection and firm performance in the literature has generally produced mixed results. The present paper contributes to the literature by using the resource-based view as a mediating process in this relationship. The study specifically tests whether or not the resource-based view of the firm mediates the positive relationships of proactive environmental management and improved environmental performance with competitive advantage, which also has consequences for financial performance. We also check the possible link between the adoption of a pioneering approach and good environmental management practices. Our findings support that early investment timing and intensity in environmental issues impact on the adoption of a proactive environmental management, which in turn helps to improve environmental performance. The findings also show that a firm's resources and competitive advantage act as mediator variables for a positive relationship between environmental protection and financial performance. This contribution is original because the present paper develops a comprehensive whole picture of this path process, which has previously only been partially discussed in the literature. In addition, this study clarifies a relevant point in the literature, namely that the effect of environmental protection on firm performance is not direct and can vary depending on the sector considered. Whereas competitive advantage in relation to costs influences financial performance in the IPPC law sector, the relevant influence in the hotel sector comes from competitive advantage through differentiation. PMID:19482410

  5. Dioxin, agent orange

    SciTech Connect

    Gough, M.

    1986-01-01

    This book presents information on the following topics: dioxin, a prevalent problem; nobody wanted dioxin; agent organe and Vietnam; what we know about and may learn about agent orange and Veterans' health; agent organe and birth defects; dioxin in Missouri; 2, 4, 5-T: the U.S.' disappearing herbicide; Seveso: high-level environmental exposure; the nitro explosion; industrial exposures to dioxin; company behavior in the face of dioxin exposures; dioxin and specific cancers; animal tests of dioxin toxicity; dioxin decions; the present and the future.

  6. Electric power market agent design

    NASA Astrophysics Data System (ADS)

    Oh, Hyungseon

    The electric power industry in many countries has been restructured in the hope of a more economically efficient system. In the restructured system, traditional operating and planning tools based on true marginal cost do not perform well since information required is strictly confidential. For developing a new tool, it is necessary to understand offer behavior. The main objective of this study is to create a new tool for power system planning. For the purpose, this dissertation develops models for a market and market participants. A new model is developed in this work for explaining a supply-side offer curve, and several variables are introduced to characterize the curve. Demand is estimated using a neural network, and a numerical optimization process is used to determine the values of the variables that maximize the profit of the agent. The amount of data required for the optimization is chosen with the aid of nonlinear dynamics. To suggest an optimal demand-side bidding function, two optimization problems are constructed and solved for maximizing consumer satisfaction based on the properties of two different types of demands: price-based demand and must-be-served demand. Several different simulations are performed to test how an agent reacts in various situations. The offer behavior depends on locational benefit as well as the offer strategies of competitors.

  7. Research and Simulation on Application of the Mobile IP Network

    NASA Astrophysics Data System (ADS)

    Yibing, Deng; Wei, Hu; Minghui, Li; Feng, Gao; Junyi, Shen

    The paper analysed the mobile node, home agent, and foreign agent of mobile IP network firstly, some key technique, such as mobile IP network basical principle, protocol work principle, agent discovery, registration, and IP packet transmission, were discussed. Then a network simulation model was designed, validating the characteristic of mobile IP network, and some advantages, which were brought by mobile network, were testified. Finally, the conclusion is gained: mobile IP network could realize the expectation of consumer that they can communicate with others anywhere.

  8. Acting as a Change Agent in Supporting Sustainable Agriculture: How to Cope with New Professional Situations?

    ERIC Educational Resources Information Center

    Cerf, M.; Guillot, M. N.; Olry, P.

    2011-01-01

    How do change agents deal with the diversity of farmers' attitudes towards the future of agriculture? How do they themselves cope with change and understand their role as change agents? We chose a comprehensive, action-training approach to answer such questions and worked with agents belonging to two different extension networks. The agents…

  9. Gradually truncated log-normal in USA publicly traded firm size distribution

    NASA Astrophysics Data System (ADS)

    Gupta, Hari M.; Campanha, José R.; de Aguiar, Daniela R.; Queiroz, Gabriel A.; Raheja, Charu G.

    2007-03-01

    We study the statistical distribution of firm size for USA and Brazilian publicly traded firms through the Zipf plot technique. Sale size is used to measure firm size. The Brazilian firm size distribution is given by a log-normal distribution without any adjustable parameter. However, we also need to consider different parameters of log-normal distribution for the largest firms in the distribution, which are mostly foreign firms. The log-normal distribution has to be gradually truncated after a certain critical value for USA firms. Therefore, the original hypothesis of proportional effect proposed by Gibrat is valid with some modification for very large firms. We also consider the possible mechanisms behind this distribution.

  10. Strategic Management Training and Commitment to Planning: Critical Partners in Stimulating Firm Performance.

    ERIC Educational Resources Information Center

    Newkirk-Moore, Susan; Bracker, Jeffrey S.

    1998-01-01

    A study of 157 small financial firms found a significant relationship between strategic management training for senior managers and the firm's level of commitment to planning, resulting in a return on investment for stockholders. (SK)

  11. Agent oriented programming

    NASA Technical Reports Server (NTRS)

    Shoham, Yoav

    1994-01-01

    The goal of our research is a methodology for creating robust software in distributed and dynamic environments. The approach taken is to endow software objects with explicit information about one another, to have them interact through a commitment mechanism, and to equip them with a speech-acty communication language. System-level applications include software interoperation and compositionality. A government application of specific interest is an infrastructure for coordination among multiple planners. Daily activity applications include personal software assistants, such as programmable email, scheduling, and new group agents. Research topics include definition of mental state of agents, design of agent languages as well as interpreters for those languages, and mechanisms for coordination within agent societies such as artificial social laws and conventions.

  12. Radioactive diagnostic agent

    SciTech Connect

    Shigematsu, A.; Aihara, M.; Matsuda, M.; Suzuki, A.; Tsuya, A.

    1984-02-07

    A radioactive diagnostic agent for renal cortex, adrenal cortex, myocardium, brain stem, spinal nerve, etc., which comprises as an essential component monoiodoacetic acid wherein the iodine atom is radioactive.

  13. Riot Control Agents

    MedlinePlus

    ... your clothing, rapidly wash your entire body with soap and water, and get medical care as quickly ... agent from your skin with large amounts of soap and water. Washing with soap and water will ...

  14. Design and simulation of material-integrated distributed sensor processing with a code-based agent platform and mobile multi-agent systems.

    PubMed

    Bosse, Stefan

    2015-01-01

    Multi-agent systems (MAS) can be used for decentralized and self-organizing data processing in a distributed system, like a resource-constrained sensor network, enabling distributed information extraction, for example, based on pattern recognition and self-organization, by decomposing complex tasks in simpler cooperative agents. Reliable MAS-based data processing approaches can aid the material-integration of structural-monitoring applications, with agent processing platforms scaled to the microchip level. The agent behavior, based on a dynamic activity-transition graph (ATG) model, is implemented with program code storing the control and the data state of an agent, which is novel. The program code can be modified by the agent itself using code morphing techniques and is capable of migrating in the network between nodes. The program code is a self-contained unit (a container) and embeds the agent data, the initialization instructions and the ATG behavior implementation. The microchip agent processing platform used for the execution of the agent code is a standalone multi-core stack machine with a zero-operand instruction format, leading to a small-sized agent program code, low system complexity and high system performance. The agent processing is token-queue-based, similar to Petri-nets. The agent platform can be implemented in software, too, offering compatibility at the operational and code level, supporting agent processing in strong heterogeneous networks. In this work, the agent platform embedded in a large-scale distributed sensor network is simulated at the architectural level by using agent-based simulation techniques. PMID:25690550

  15. Design and Simulation of Material-Integrated Distributed Sensor Processing with a Code-Based Agent Platform and Mobile Multi-Agent Systems

    PubMed Central

    Bosse, Stefan

    2015-01-01

    Multi-agent systems (MAS) can be used for decentralized and self-organizing data processing in a distributed system, like a resource-constrained sensor network, enabling distributed information extraction, for example, based on pattern recognition and self-organization, by decomposing complex tasks in simpler cooperative agents. Reliable MAS-based data processing approaches can aid the material-integration of structural-monitoring applications, with agent processing platforms scaled to the microchip level. The agent behavior, based on a dynamic activity-transition graph (ATG) model, is implemented with program code storing the control and the data state of an agent, which is novel. The program code can be modified by the agent itself using code morphing techniques and is capable of migrating in the network between nodes. The program code is a self-contained unit (a container) and embeds the agent data, the initialization instructions and the ATG behavior implementation. The microchip agent processing platform used for the execution of the agent code is a standalone multi-core stack machine with a zero-operand instruction format, leading to a small-sized agent program code, low system complexity and high system performance. The agent processing is token-queue-based, similar to Petri-nets. The agent platform can be implemented in software, too, offering compatibility at the operational and code level, supporting agent processing in strong heterogeneous networks. In this work, the agent platform embedded in a large-scale distributed sensor network is simulated at the architectural level by using agent-based simulation techniques. PMID:25690550

  16. Protecting software agents from malicious hosts using quantum computing

    NASA Astrophysics Data System (ADS)

    Reisner, John; Donkor, Eric

    2000-07-01

    We evaluate how quantum computing can be applied to security problems for software agents. Agent-based computing, which merges technological advances in artificial intelligence and mobile computing, is a rapidly growing domain, especially in applications such as electronic commerce, network management, information retrieval, and mission planning. System security is one of the more eminent research areas in agent-based computing, and the specific problem of protecting a mobile agent from a potentially hostile host is one of the most difficult of these challenges. In this work, we describe our agent model, and discuss the capabilities and limitations of classical solutions to the malicious host problem. Quantum computing may be extremely helpful in addressing the limitations of classical solutions to this problem. This paper highlights some of the areas where quantum computing could be applied to agent security.

  17. Comparison and fusion of four nondestructive sensors for predicting apple fruit firmness and soluble solids content

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Four nondestructive technologies (i.e., acoustic firmness, bioyield firmness, visible/near-infrared (NIR) spectroscopy, and spectral scattering) have been developed in recent years for assessing the firmness and/or soluble solids content (SSC) of apples. Each of these technologies has its merits and...

  18. Information Systems, Competitive Dynamics, and Firm Performance: An Interpretive and Centering Resonance Analysis

    ERIC Educational Resources Information Center

    Vannoy, Sandra A.

    2010-01-01

    This dissertation examines, from a managerial interpretive perspective, how information systems contribute to firms' specific competitive actions and responses, and the resultant impacts upon firm performance. The findings from this research suggest that the answer may well lie within the role of information systems in firms' competitive dynamics…

  19. Distinctive Human Resources Are the Core Competencies of Firms. EQW Working Papers WP18.

    ERIC Educational Resources Information Center

    Cappelli, Peter; Crocker-Hefter, Anne

    The interrelationship between people management practices and product market/competition was examined in a series of case comparisons of pairs of firms/organizations of the following types: professional sports teams, military services, retailing firms, information service firms, business schools, financial services, shipping services, and food and…

  20. 75 FR 66796 - Pricewaterhousecoopers LLP (“PwC”), Internal Firm Services Client Account Administrators Group...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-29

    ... Services, Atlanta, Georgia. The notice was published in the Federal Register on June 7, 2010 (75 FR 32224... Employment and Training Administration Pricewaterhousecoopers LLP (``PwC''), Internal Firm Services Client... subject firm should read PricewaterhouseCoopers LLP (``PwC''), Internal Firm Services Client...

  1. Measuring Economic Discrimination of Hispanic-Owned Architecture and Engineering Firms in South Florida

    ERIC Educational Resources Information Center

    Carvajal, Manuel J.

    2004-01-01

    Using data developed for the U.S. District Court, this study compared the performance of Hispanic-owned firms and two groupings of non-Hispanic-owned firms in three South Florida markets: architecture (n= 176), structural engineering (n= 144), and civil engineering (n = 200). Within each market, firms?earnings are expressed as functions of…

  2. Organizational Response to Public Relations: An Empirical Study of Firms in Singapore.

    ERIC Educational Resources Information Center

    Wee, Chow-Hou; And Others

    1996-01-01

    Assesses implications of the strategic management aspect of public relations for firms in Singapore. Focuses on how firms with differing organizational structure/background respond to the challenges of executing core public relations activities. Finds that manufacturing firms pay less attention to customer relations than service organizations, and…

  3. 49 CFR 1522.121 - Security threat assessments for personnel of TSA-approved validation firms.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...-approved validation firms. 1522.121 Section 1522.121 Transportation Other Regulations Relating to... FOR ALL MODES OF TRANSPORTATION TSA-APPROVED VALIDATION FIRMS AND VALIDATORS TSA-Approved Validation... for personnel of TSA-approved validation firms. Each of the following must successfully complete...

  4. Workplace Learning and Its Organizational Benefits for Small Enterprises: Evidence from Greek Industrial Firms

    ERIC Educational Resources Information Center

    Panagiotakopoulos, Antonios

    2011-01-01

    Purpose: The purpose of this study is to explore small firm owners' perceptions of the impact of employee training on small firm competitiveness in the context of Greece. Design/methodology/approach: The research adopts a qualitative orientation. Empirical data were collected from 43 owners of small and micro-firms operating in various sectors of…

  5. 23 CFR 636.207 - Is there a limit on short listed firms?

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 23 Highways 1 2010-04-01 2010-04-01 false Is there a limit on short listed firms? 636.207 Section... OPERATIONS DESIGN-BUILD CONTRACTING Selection Procedures, Award Criteria § 636.207 Is there a limit on short listed firms? Normally, three to five firms are short listed, however, the maximum number specified...

  6. 23 CFR 636.207 - Is there a limit on short listed firms?

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 23 Highways 1 2011-04-01 2011-04-01 false Is there a limit on short listed firms? 636.207 Section... OPERATIONS DESIGN-BUILD CONTRACTING Selection Procedures, Award Criteria § 636.207 Is there a limit on short listed firms? Normally, three to five firms are short listed, however, the maximum number specified...

  7. Environmental-scanning behavior among private practice physical therapy firms.

    PubMed

    Schafer, D S

    1991-06-01

    This study examined the extent to which private practice physical therapy firms focused on specific environmental sectors in the process of making business decisions. Furthermore, the relationship between scanning behavior and both entrepreneurship level (high, middle, low) and direct-access status (complete, partial, none) were analyzed. The sample consisted of 450 randomly selected private practice decision makers (eg, owners, chief executive officers) from throughout the United States. Data were gathered using a mailed, structured questionnaire. Physical therapy private practices were found to differentially attend to environmental sectors with the customer sector ranked the highest followed, in descending order, by the technological, regulatory, socio-cultural-political, competitive, and economic sectors. In addition, firms in the high-level entrepreneurship group scanned the technological and marketing (customer, competitive) environments to a significantly greater degree than did the middle- and low-level groups. Direct-access status had no effect on scanning behavior. PMID:2034711

  8. Improving productivity and firm performance with enterprise resource planning

    NASA Astrophysics Data System (ADS)

    Beheshti, Hooshang M.; Beheshti, Cyrus M.

    2010-11-01

    Productivity is generally considered to be the efficient utilisation of organisational resources and is measured in terms of the efficiency of a worker, company or nation. Focusing on efficiency alone, however, can be harmful to the organisation's long-term success and competitiveness. The full benefits of productivity improvement measures are realised when productivity is examined from two perspectives: operational efficiency (output/input) of an individual worker or a business unit as well as performance (effectiveness) with regard to end user or customer satisfaction. Over the years, corporations have adopted new technology to integrate business activities in order to achieve both effectiveness and efficiency in their operations. In recent years, many firms have invested in enterprise resource planning (ERP) in order to integrate all business activities into a uniform system. The implementation of ERP enables the firm to reduce the transaction costs of the business and improve its productivity, customer satisfaction and profitability.

  9. Infantile myofibroma: a firm, round plaque in an infant.

    PubMed

    Amano, Shinya; Halsey, Mark; Yasuda, Mariko; O'Donnell, Patrick; Csikesz, Courtney

    2016-01-01

    Infantile myofibroma is a rare fibromatous tumor that is variable in presentation and is frequently mistaken for hemangioma or rhabdomyosarcoma. We describe a 14-month-old boy who presented with multiple, enlarging, firm lesions on the shoulder. Biopsy revealed a proliferation of small spindle cells with myxoid and hyalinized stroma infiltrating into the superficial adipose tissue. We provide a brief review of the clinical presentation, histopathologic features, management, and recent advances in our understanding of this rare condition. PMID:27617527

  10. Environmental policy, adjustment costs, and behavior of the firm

    SciTech Connect

    Xepapadeas, A.P. )

    1992-11-01

    The effects of environmental policy, in the form of emission charges or emission limits, on the firm's optimal choices of productive and abatement inputs are analyzed. Short-run and long-run impacts on inputs, and the properties of static emission function, are determined through comparative static analysis. Comparative dynamics reveal the properties of the cumulative emission function and the cumulative shadow-cost-of-emission-limits function. 10 refs.

  11. Environmental management and firm performance: a case study.

    PubMed

    Claver, Enrique; López, María D; Molina, José F; Tarí, Juan J

    2007-09-01

    This study has as its aim to help to clarify the relationship between environmental management and economic performance by integrating it into a wider framework that includes the relationship between environmental strategy and firm performance, the latter being understood as the combination of environmental performance, competitive advantage and economic performance. A case study of the COATO farming cooperative showed us that its environmental management, focused on prevention logic, has had a positive net effect on its environmental performance. Besides, the order in which these practices were adopted favoured the development of new organisational capabilities that have contributed to the appearance of advantages derived from the greater accumulated experience of employees in creating new projects that are designed to reduce residues and pollution. COATO has also obtained a competitive advantage in differentiation thanks to an improved brand image and to its increased credibility in business relationships. Finally, a positive correlation exists between the pioneering proactive strategy adopted by this cooperative and the improvement of its firm performance with respect to the other firms in its sector. PMID:17141938

  12. Agents: An approach for dynamic process modelling

    NASA Astrophysics Data System (ADS)

    Grohmann, Axel; Kopetzky, Roland; Lurk, Alexander

    1999-03-01

    With the growing amount of distributed and heterogeneous information and services, conventional information systems have come to their limits. This gave rise to the development of a Multi-Agent System (the "Logical Client") which can be used in complex information systems as well as in other advanced software systems. Computer agents are proactive, reactive and social. They form a community of independent software components that can communicate and co-operate in order to accomplish complex tasks. Thus the agent-oriented paradigm provides a new and powerful approach to programming distributed systems. The communication framework developed is based on standards like CORBA, KQML and KIF. It provides an embedded rule based system to find adequate reactions to incoming messages. The macro-architecture of the Logical Client consists of independent agents and uses artificial intelligence to cope with complex patterns of communication and actions. A set of system agents is also provided, including the Strategy Service as a core component for modelling processes at runtime, the Computer Supported Cooperative Work (CSCW) Component for supporting remote co-operation between human users and the Repository for managing and hiding the file based data flow in heterogeneous networks. This architecture seems to be capable of managing complexity in information systems. It is also being implemented in a complex simulation system that monitors and simulates the environmental radioactivity in the country Baden-Württemberg.

  13. Agent independent task planning

    NASA Technical Reports Server (NTRS)

    Davis, William S.

    1990-01-01

    Agent-Independent Planning is a technique that allows the construction of activity plans without regard to the agent that will perform them. Once generated, a plan is then validated and translated into instructions for a particular agent, whether a robot, crewmember, or software-based control system. Because Space Station Freedom (SSF) is planned for orbital operations for approximately thirty years, it will almost certainly experience numerous enhancements and upgrades, including upgrades in robotic manipulators. Agent-Independent Planning provides the capability to construct plans for SSF operations, independent of specific robotic systems, by combining techniques of object oriented modeling, nonlinear planning and temporal logic. Since a plan is validated using the physical and functional models of a particular agent, new robotic systems can be developed and integrated with existing operations in a robust manner. This technique also provides the capability to generate plans for crewmembers with varying skill levels, and later apply these same plans to more sophisticated robotic manipulators made available by evolutions in technology.

  14. Stability of equilibrium in a nonlinear Cournot oligopoly with five firms

    NASA Astrophysics Data System (ADS)

    Ibrahim, Adyda

    2014-07-01

    This paper considers an n firms oligopoly model with isoelastic demand function and linear cost function. The reaction functions of these firms are determined from these functions, and a dynamical system with naive adaptive process is produced. The equilibrium of this n dimensional system is obtained. In the case of homogeneous firms, the equilibrium becomes unstable when the number of firms is five. By introducing heterogeneity into the five firms' model, the equilibrium becomes stable and there is a path connecting the stable and unstable equilibrium.

  15. The effect of heating technologies on CO(2) and energy efficiency of Dutch greenhouse firms.

    PubMed

    Oude Lansink, Alfons; Bezlepkin, Igor

    2003-05-01

    This paper uses Data Envelopment Analysis to compute measures of the efficiency (relative to a frontier) in terms of the use of all inputs as well as for single inputs like CO(2) and energy for a sample of greenhouse firms in the Netherlands over the period 1991-1995. These efficiency measures are generated for different firms specialised in production of vegetables, flowers, and potplants and with different heating technologies. The empirical results indicate that firms use energy quite efficiently and are less efficient in terms of CO(2) emissions. Firms using conventional heating are overall less efficiently using energy and CO(2) than firms using more advanced heating technologies. Most differences in efficiency between firm types and firms using different heating technologies are statistically significant. Scale adjustments can provide an important contribution to further efficiency improvements. PMID:12767863

  16. MpcAgent

    SciTech Connect

    Nutaro, James

    2013-11-29

    MpcAgent software is a module for the VolltronLite platform from PNNL that regulates the operation of rooftop air conditioning units in small to medium commercial buildings for the purpose of reducing peak power consumption. The MpcAgent accomplishes this by restricting the number of units that may operate simultaneously and using a model predictive control strategy to select which units to operate in each control period. The outcome of this control is effective control of the building air temperature at the user specified set point while avoiding expensive peak demand charges that result from running all HVAC units simultaneously.

  17. MpcAgent

    Energy Science and Technology Software Center (ESTSC)

    2013-11-29

    MpcAgent software is a module for the VolltronLite platform from PNNL that regulates the operation of rooftop air conditioning units in small to medium commercial buildings for the purpose of reducing peak power consumption. The MpcAgent accomplishes this by restricting the number of units that may operate simultaneously and using a model predictive control strategy to select which units to operate in each control period. The outcome of this control is effective control of themore » building air temperature at the user specified set point while avoiding expensive peak demand charges that result from running all HVAC units simultaneously.« less

  18. Gadofullerene MRI contrast agents.

    PubMed

    Bolskar, Robert D

    2008-04-01

    A promising new class of MRI contrast-enhancing agents with high relaxivities is based on gadolinium-containing metallofullerenes, which are also termed gadofullerenes. Detailed study of the water-proton relaxivity properties and intermolecular nanoclustering behavior of gadofullerene derivatives has revealed valuable information about their relaxivity mechanisms and given a deeper understanding of this new class of paramagnetic contrast agent. Here, the latest findings on water-solubilized gadofullerene materials and how these findings relate to their future applications in MRI are reviewed and discussed. PMID:18373426

  19. Allelomimesis as a generic clustering mechanism for interacting agents

    NASA Astrophysics Data System (ADS)

    Juanico, Dranreb Earl; Monterola, Christopher; Saloma, Caesar

    2003-03-01

    We show that allelomimesis is a generic mechanism that could explain why the cluster-size distribution D( s) of diverse social aggregates such as animal groups and socio-economic entities all fit into a power-law distribution: D( s)∝ s- τ, where τ is the critical exponent. Roughly, allelomimesis is the tendency of an agent to imitate the actions of its neighbors. A cellular automata model of allelomimesis yields a population-age distribution which is consistent with the assumption of evolutionary biologists that isolation does not enhance the life expectancies of agents. Dependence of τ with degree of allelomimesis is highly nonlinear. The different experimental τ values yielded by the size distributions of real systems such as fish schools, African buffalo herds, US financial firms, and towns around London and Berlin, might be understood as arising from the varying degrees of allelomimesis by system constituents.

  20. A two-level complex network model and its application

    NASA Astrophysics Data System (ADS)

    Yang, Jianmei; Wang, Wenjie; Chen, Guanrong

    2009-06-01

    This paper investigates the competitive relationship and rivalry of industrial markets, using Chinese household electrical appliance firms as a platform for the study. The common complex network models belong to one-level networks in layered classification, while this paper formulates and evaluates a new two-level network model, in which the first level is the whole unweighted-undirected network useful for macro-analyzing the industrial market structure while the second level is a local weighted-directed network capable of micro-analyzing the inter-firm rivalry in the market. It is believed that the relationship is determined by objective factors whereas the action is rather subjective, and the idea in this paper lies in that the objective relationship and the subjective action subjected to this relationship are being simultaneously considered but at deferent levels of the model which may be applicable to many real applications.

  1. Agent Persuasion Mechanism of Acquaintance

    NASA Astrophysics Data System (ADS)

    Jinghua, Wu; Wenguang, Lu; Hailiang, Meng

    Agent persuasion can improve negotiation efficiency in dynamic environment based on its initiative and autonomy, and etc., which is being affected much more by acquaintance. Classification of acquaintance on agent persuasion is illustrated, and the agent persuasion model of acquaintance is also illustrated. Then the concept of agent persuasion degree of acquaintance is given. Finally, relative interactive mechanism is elaborated.

  2. 13 CFR 107.1620 - Functions of agents, including Central Registration Agent, Selling Agent and Fiscal Agent.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false Functions of agents, including Central Registration Agent, Selling Agent and Fiscal Agent. 107.1620 Section 107.1620 Business Credit and Assistance SMALL BUSINESS ADMINISTRATION SMALL BUSINESS INVESTMENT COMPANIES SBA Financial Assistance...

  3. 13 CFR 108.1620 - Functions of agents, including Central Registration Agent, Selling Agent and Fiscal Agent.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false Functions of agents, including Central Registration Agent, Selling Agent and Fiscal Agent. 108.1620 Section 108.1620 Business Credit and Assistance SMALL BUSINESS ADMINISTRATION NEW MARKETS VENTURE CAPITAL (âNMVCâ) PROGRAM SBA...

  4. GENERAL: Consensus protocol for multi-agent continuous systems

    NASA Astrophysics Data System (ADS)

    Tan, Fu-Xiao; Guan, Xin-Ping; Liu, De-Rong

    2008-10-01

    Based on the algebraic graph theory, the networked multi-agent continuous systems are investigated. Firstly, the digraph (directed graph) represents the topology of a networked system, and then a consensus convergence criterion of system is proposed. Secondly, the issue of stability of multi-agent systems and the consensus convergence problem of information states are all analysed. Furthermore, the consensus equilibrium point of system is proved to be global and asymptotically reach the convex combination of initial states. Finally, two examples are taken to show the effectiveness of the results obtained in this paper.

  5. Can Subscription Agents Survive?

    ERIC Educational Resources Information Center

    Tuttle, Marcia

    1985-01-01

    With the saturation of traditional markets for their services, subscription agents have evolved from orders and invoices to serving customers by communicating with librarians and publishers and making automated and paper products available. Magazine fulfillment centers, publisher discounts, and electronic publishing will influence the subscription…

  6. Remote Agent Experiment

    NASA Technical Reports Server (NTRS)

    Benard, Doug; Dorais, Gregory A.; Gamble, Ed; Kanefsky, Bob; Kurien, James; Millar, William; Muscettola, Nicola; Nayak, Pandu; Rouquette, Nicolas; Rajan, Kanna; Norvig, Peter (Technical Monitor)

    2000-01-01

    Remote Agent (RA) is a model-based, reusable artificial intelligence (At) software system that enables goal-based spacecraft commanding and robust fault recovery. RA was flight validated during an experiment on board of DS1 between May 17th and May 21th, 1999.

  7. E-Learning Agents

    ERIC Educational Resources Information Center

    Gregg, Dawn G.

    2007-01-01

    Purpose: The purpose of this paper is to illustrate the advantages of using intelligent agents to facilitate the location and customization of appropriate e-learning resources and to foster collaboration in e-learning environments. Design/methodology/approach: This paper proposes an e-learning environment that can be used to provide customized…

  8. Mobility control agent

    SciTech Connect

    Argabright, P.A.; Phillips, B.L.; Rhudy, J.S.

    1983-05-17

    Polymer mobility control agents useful in supplemental oil recovery processes, which give improved reciprocal relative mobilities, are prepared by initiating the polymerization of a monomer containing a vinyl group with a catalyst comprising a persulfate and ferrous ammonium sulfate. The vinyl monomer is an acrylyl, a vinyl cyanide, a styryl and water soluble salts thereof.

  9. Wealth condensation in a Barabasi-Albert network

    NASA Astrophysics Data System (ADS)

    Vázquez-Montejo, J.; Huerta-Quintanilla, R.; Rodríguez-Achach, M.

    2010-04-01

    We study the flow of money among agents in a Barabasi-Albert (BA) scale free network, where each network node represents an agent and money exchange interactions are established through links. The system allows money trade between two agents at a time, betting a fraction f of the poorer’s agent wealth. We also allow for the bet to be biased, giving the poorer agent a winning probability p. In the no network case there is a phase transition involving a relationship between p and f. In the networked case, we also found a condensation interface, however, this is not a complete condensation due to the presence of clusters in the network and its topology. As can be expected, the winner is always a well-connected agent, but we also found that the mean wealth decreases with the agents’ connectivity.

  10. Systemic risk on different interbank network topologies

    NASA Astrophysics Data System (ADS)

    Lenzu, Simone; Tedeschi, Gabriele

    2012-09-01

    In this paper we develop an interbank market with heterogeneous financial institutions that enter into lending agreements on different network structures. Credit relationships (links) evolve endogenously via a fitness mechanism based on agents' performance. By changing the agent's trust on its neighbor's performance, interbank linkages self-organize themselves into very different network architectures, ranging from random to scale-free topologies. We study which network architecture can make the financial system more resilient to random attacks and how systemic risk spreads over the network. To perturb the system, we generate a random attack via a liquidity shock. The hit bank is not automatically eliminated, but its failure is endogenously driven by its incapacity to raise liquidity in the interbank network. Our analysis shows that a random financial network can be more resilient than a scale free one in case of agents' heterogeneity.

  11. Influence of a network structure on the network effect in the communication service market

    NASA Astrophysics Data System (ADS)

    Uchida, Makoto; Shirayama, Susumu

    2008-09-01

    In this study, we analyze the network effect in a model of a personal communication market, by using a multi-agent based simulation approach. We introduce into the simulation model complex network structures as the interaction patterns of agents. With complex network models, we investigate the dynamics of a market in which two providers are competing. We also examine the structure of networks that affect the complex behavior of the market. By a series of simulations, we show that the structural properties of complex networks, such as the clustering coefficient and degree correlation, have a major influence on the dynamics of the market. We find that the network effect is increased if the interaction pattern of agents is characterized by a high clustering coefficient, or a positive degree correlation. We also discuss a suitable model of the interaction pattern for reproducing market dynamics in the real world, by performing simulations using real data of a social network.

  12. Adaptation and Learning of Agents in Market Oriented Programming

    NASA Astrophysics Data System (ADS)

    Ishinishi, Masayuki; Namatame, Akira; Kita, Hajime

    Market Oriented Programming (MOP) proposed by Wellman is a decentralized control method using auction machanism inspired by the market economy. It is applied to many problems such as network and computation resource allocation. Conventional MOP models are formulated based on the concept of ‘competitive market’ of economics which assumes that the market consists of sufficiently many and small agents. However, in realistic applications of MOP, number of agents is limited and their interdependency is not negligible. In this paper, MOP for interdependent agents is discussed. An oligopoly market model for MOP is introduced, and adaptation process of interdependent agents and its stability are discussed. Further, it is also demonstrated that selfish learning of adaptation coefficiency by each agent achieves stability of market through computer simulation.

  13. AFECS. multi-agent framework for experiment control systems

    NASA Astrophysics Data System (ADS)

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

    2008-07-01

    AFECS is a pure Java based software framework for designing and implementing distributed control systems. AFECS creates a control system environment as a collection of software agents behaving as finite state machines. These agents can represent real entities, such as hardware devices, software tasks, or control subsystems. A special control oriented ontology language (COOL), based on RDFS (Resource Definition Framework Schema) is provided for control system description as well as for agent communication. AFECS agents can be distributed over a variety of platforms. Agents communicate with their associated physical components using range of communication protocols, including tcl-DP, cMsg (publish-subscribe communication system developed at Jefferson Lab), SNMP (simple network management protocol), EPICS channel access protocol and JDBC.

  14. Contrast agents in diagnostic imaging: Present and future.

    PubMed

    Caschera, Luca; Lazzara, Angelo; Piergallini, Lorenzo; Ricci, Domenico; Tuscano, Bruno; Vanzulli, Angelo

    2016-08-01

    Specific contrast agents have been developed for x ray examinations (mainly CT), sonography and Magnetic Resonance Imaging. Most of them are extracellular agents which create different enhancement on basis of different vascularization or on basis of different interstitial network in tissues, but some can be targeted to a particular cell line (e.g. hepatocyte). Microbubbles can be used as carrier for therapeutic drugs which can be released in specific targets under sonographic guidance, decreasing systemic toxicity and increasing therapeutic effect. Radiologists have to choose a particular contrast agent knowing its physical and chemical properties and the possibility of adverse reactions and balancing them with the clinical benefits of a more accurate diagnosis. As for any drug, contrast agents can cause adverse events, which are more frequent with Iodine based CA, but also with Gd based CA and even with sonographic contrast agents hypersensitivity reaction can occur. PMID:27168225

  15. AFECS. Multi-Agent Framework for Experiment Control Systems

    SciTech Connect

    Vardan Gyurjyan; David Abbott; William Heyes; Edward Jastrzembski; Carl Timmer; Elliott Wolin

    2008-01-23

    AFECS is a pure Java based software framework for designing and implementing distributed control systems. AFECS creates a control system environment as a collection of software agents behaving as finite state machines. These agents can represent real entities, such as hardware devices, software tasks, or control subsystems. A special control oriented ontology language (COOL), based on RDFS (Resource Definition Framework Schema) is provided for control system description as well as for agent communication. AFECS agents can be distributed over a variety of platforms. Agents communicate with their associated physical components using range of communication protocols, including tcl-DP, cMsg (publish-subscribe communication system developed at Jefferson Lab), SNMP (simple network management protocol), EPICS channel access protocol and JDBC.

  16. Hybrid evolutionary computing model for mobile agents of wireless Internet multimedia

    NASA Astrophysics Data System (ADS)

    Hortos, William S.

    2001-03-01

    The ecosystem is used as an evolutionary paradigm of natural laws for the distributed information retrieval via mobile agents to allow the computational load to be added to server nodes of wireless networks, while reducing the traffic on communication links. Based on the Food Web model, a set of computational rules of natural balance form the outer stage to control the evolution of mobile agents providing multimedia services with a wireless Internet protocol WIP. The evolutionary model shows how mobile agents should behave with the WIP, in particular, how mobile agents can cooperate, compete and learn from each other, based on an underlying competition for radio network resources to establish the wireless connections to support the quality of service QoS of user requests. Mobile agents are also allowed to clone themselves, propagate and communicate with other agents. A two-layer model is proposed for agent evolution: the outer layer is based on the law of natural balancing, the inner layer is based on a discrete version of a Kohonen self-organizing feature map SOFM to distribute network resources to meet QoS requirements. The former is embedded in the higher OSI layers of the WIP, while the latter is used in the resource management procedures of Layer 2 and 3 of the protocol. Algorithms for the distributed computation of mobile agent evolutionary behavior are developed by adding a learning state to the agent evolution state diagram. When an agent is in an indeterminate state, it can communicate to other agents. Computing models can be replicated from other agents. Then the agents transitions to the mutating state to wait for a new information-retrieval goal. When a wireless terminal or station lacks a network resource, an agent in the suspending state can change its policy to submit to the environment before it transitions to the searching state. The agents learn the facts of agent state information entered into an external database. In the cloning process, two

  17. Betweenness centrality of fractal and nonfractal scale-free model networks and tests on real networks

    NASA Astrophysics Data System (ADS)

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

    2007-05-01

    We study the betweenness centrality of fractal and nonfractal scale-free network models as well as real networks. We show that the correlation between degree and betweenness centrality C of nodes is much weaker in fractal network models compared to nonfractal models. We also show that nodes of both fractal and nonfractal scale-free networks have power-law betweenness centrality distribution P(C)˜C-δ . We find that for nonfractal scale-free networks δ=2 , and for fractal scale-free networks δ=2-1/dB , where dB is the dimension of the fractal network. We support these results by explicit calculations on four real networks: pharmaceutical firms (N=6776) , yeast (N=1458) , WWW (N=2526) , and a sample of Internet network at the autonomous system level (N=20566) , where N is the number of nodes in the largest connected component of a network. We also study the crossover phenomenon from fractal to nonfractal networks upon adding random edges to a fractal network. We show that the crossover length ℓ* , separating fractal and nonfractal regimes, scales with dimension dB of the network as p-1/dB , where p is the density of random edges added to the network. We find that the correlation between degree and betweenness centrality increases with p .

  18. An analysis of the size distribution of Italian firms by age

    NASA Astrophysics Data System (ADS)

    Cirillo, Pasquale

    2010-02-01

    In this paper we analyze the size distribution of Italian firms by age. In other words, we want to establish whether the way that the size of firms is distributed varies as firms become old. As a proxy of size we use capital. In [L.M.B. Cabral, J. Mata, On the evolution of the firm size distribution: Facts and theory, American Economic Review 93 (2003) 1075-1090], the authors study the distribution of Portuguese firms and they find out that, while the size distribution of all firms is fairly stable over time, the distributions of firms by age groups are appreciably different. In particular, as the age of the firms increases, their size distribution on the log scale shifts to the right, the left tails becomes thinner and the right tail thicker, with a clear decrease of the skewness. In this paper, we perform a similar analysis with Italian firms using the CEBI database, also considering firms’ growth rates. Although there are several papers dealing with Italian firms and their size distribution, to our knowledge a similar study concerning size and age has not been performed yet for Italy, especially with such a big panel.

  19. Application of Intelligent Agents in a Notice and Takedown Process

    NASA Astrophysics Data System (ADS)

    De Rosa, Alessia; Bartolini, Franco; Piva, Alessandro

    2003-01-01

    The future development of networked multimedia services is conditioned by the achievement of efficient methods to protect data owners against non-authorised copying and redistribution of the material put on the network, to grant that the Intellectual Property Rights (IRP) are well respected and the assets properly managed. A Notice and Takedown Procedure is considered, based on a self-regulatory regime, and as a possible implementation of this system, an Intelligent Agent based platform is proposed.

  20. 48 CFR 1019.202-70-10 - Application process for mentor firms to participate in the program.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... mentor firms to participate in the program. 1019.202-70-10 Section 1019.202-70-10 Federal Acquisition...-70-10 Application process for mentor firms to participate in the program. (a) Firm interested in becoming a mentor firm may apply in writing to Treasury's OSBD. The application will be evaluated...