A service-oriented architecture for integrating the modeling and formal verification of genetic regulatory networks

Directory of Open Access Journals (Sweden)

Page Michel

2009-12-01

Full Text Available Abstract Background The study of biological networks has led to the development of increasingly large and detailed models. Computer tools are essential for the simulation of the dynamical behavior of the networks from the model. However, as the size of the models grows, it becomes infeasible to manually verify the predictions against experimental data or identify interesting features in a large number of simulation traces. Formal verification based on temporal logic and model checking provides promising methods to automate and scale the analysis of the models. However, a framework that tightly integrates modeling and simulation tools with model checkers is currently missing, on both the conceptual and the implementational level. Results We have developed a generic and modular web service, based on a service-oriented architecture, for integrating the modeling and formal verification of genetic regulatory networks. The architecture has been implemented in the context of the qualitative modeling and simulation tool GNA and the model checkers NUSMV and CADP. GNA has been extended with a verification module for the specification and checking of biological properties. The verification module also allows the display and visual inspection of the verification results. Conclusions The practical use of the proposed web service is illustrated by means of a scenario involving the analysis of a qualitative model of the carbon starvation response in E. coli. The service-oriented architecture allows modelers to define the model and proceed with the specification and formal verification of the biological properties by means of a unified graphical user interface. This guarantees a transparent access to formal verification technology for modelers of genetic regulatory networks.

Formal Specification Based Automatic Test Generation for Embedded Network Systems

Directory of Open Access Journals (Sweden)

Eun Hye Choi

2014-01-01

Full Text Available Embedded systems have become increasingly connected and communicate with each other, forming large-scaled and complicated network systems. To make their design and testing more reliable and robust, this paper proposes a formal specification language called SENS and a SENS-based automatic test generation tool called TGSENS. Our approach is summarized as follows: (1 A user describes requirements of target embedded network systems by logical property-based constraints using SENS. (2 Given SENS specifications, test cases are automatically generated using a SAT-based solver. Filtering mechanisms to select efficient test cases are also available in our tool. (3 In addition, given a testing goal by the user, test sequences are automatically extracted from exhaustive test cases. We’ve implemented our approach and conducted several experiments on practical case studies. Through the experiments, we confirmed the efficiency of our approach in design and test generation of real embedded air-conditioning network systems.

Revealing dynamics and consequences of fit and misfit between formal and informal networks in multi-institutional product development collaborations

NARCIS (Netherlands)

Kratzer, J.; Gemuenden, Hans G.; Lettl, Christopher

The study presents a longitudinal examination about dynamics and consequences of fit and misfit between formally ascribed design interfaces and informal communication networks in two large multi-institutional product development collaborations in space industry. Findings: (1) formally ascribed

CellNOptR: a flexible toolkit to train protein signaling networks to data using multiple logic formalisms.

Science.gov (United States)

Terfve, Camille; Cokelaer, Thomas; Henriques, David; MacNamara, Aidan; Goncalves, Emanuel; Morris, Melody K; van Iersel, Martijn; Lauffenburger, Douglas A; Saez-Rodriguez, Julio

2012-10-18

Cells process signals using complex and dynamic networks. Studying how this is performed in a context and cell type specific way is essential to understand signaling both in physiological and diseased situations. Context-specific medium/high throughput proteomic data measured upon perturbation is now relatively easy to obtain but formalisms that can take advantage of these features to build models of signaling are still comparatively scarce. Here we present CellNOptR, an open-source R software package for building predictive logic models of signaling networks by training networks derived from prior knowledge to signaling (typically phosphoproteomic) data. CellNOptR features different logic formalisms, from Boolean models to differential equations, in a common framework. These different logic model representations accommodate state and time values with increasing levels of detail. We provide in addition an interface via Cytoscape (CytoCopteR) to facilitate use and integration with Cytoscape network-based capabilities. Models generated with this pipeline have two key features. First, they are constrained by prior knowledge about the network but trained to data. They are therefore context and cell line specific, which results in enhanced predictive and mechanistic insights. Second, they can be built using different logic formalisms depending on the richness of the available data. Models built with CellNOptR are useful tools to understand how signals are processed by cells and how this is altered in disease. They can be used to predict the effect of perturbations (individual or in combinations), and potentially to engineer therapies that have differential effects/side effects depending on the cell type or context.

Creating and shaping innovation systems: Formal networks in the innovation system for stationary fuel cells in Germany

International Nuclear Information System (INIS)

Musiolik, Joerg; Markard, Jochen

2011-01-01

The development and diffusion of novel technologies, e.g. for decentralized energy generation, crucially depends on supportive institutional structures such as R and D programs, specific regulations, technical standards, or positive expectations. Such structures are not given but emerge through the interplay of different kinds of actors. In this paper, we study the role of formal networks in creating supportive structures in the technological innovation system for stationary fuel cells in Germany. Our findings are based on an in-depth study of five selected innovation networks. The analysis shows that the networks were strategically set up to support the creation of a variety of elements including public R and D programs, modules for vocational training, technical guidelines, standardized components, or a positive image of the technology. These elements have been reported to generate positive externalities in the field, e.g. as they help to establish user-supplier linkages in the emerging value chain. We conclude that, from a firm perspective such elements may represent strategically relevant resources made available at the innovation system level. This view opens up a link to the literature of strategic management, thus highlighting the importance of strategic action and cooperation in emerging technological fields. - Research Highlights: → We combine technological innovation systems with resource-based reasoning. → Formal networks are strategically set up to create and shape technological innovation systems. → Formal networks create system resources which provide positive externalities in emerging fields. → Collective action is essential for the build-up of energy innovation systems.

Creating and shaping innovation systems: Formal networks in the innovation system for stationary fuel cells in Germany

Energy Technology Data Exchange (ETDEWEB)

Musiolik, Joerg, E-mail: joerg.musiolik@eawag.c [Cirus - Innovation Research in Utility Sectors, Eawag, Swiss Federal Institute of Aquatic Science and Technology, Uberlandstrasse 133, 8600 Duebendorf (Switzerland); Markard, Jochen [Cirus - Innovation Research in Utility Sectors, Eawag, Swiss Federal Institute of Aquatic Science and Technology, Uberlandstrasse 133, 8600 Duebendorf (Switzerland)

2011-04-15

The development and diffusion of novel technologies, e.g. for decentralized energy generation, crucially depends on supportive institutional structures such as R and D programs, specific regulations, technical standards, or positive expectations. Such structures are not given but emerge through the interplay of different kinds of actors. In this paper, we study the role of formal networks in creating supportive structures in the technological innovation system for stationary fuel cells in Germany. Our findings are based on an in-depth study of five selected innovation networks. The analysis shows that the networks were strategically set up to support the creation of a variety of elements including public R and D programs, modules for vocational training, technical guidelines, standardized components, or a positive image of the technology. These elements have been reported to generate positive externalities in the field, e.g. as they help to establish user-supplier linkages in the emerging value chain. We conclude that, from a firm perspective such elements may represent strategically relevant resources made available at the innovation system level. This view opens up a link to the literature of strategic management, thus highlighting the importance of strategic action and cooperation in emerging technological fields. - Research Highlights: {yields} We combine technological innovation systems with resource-based reasoning. {yields} Formal networks are strategically set up to create and shape technological innovation systems. {yields} Formal networks create system resources which provide positive externalities in emerging fields. {yields} Collective action is essential for the build-up of energy innovation systems.

COORDINATION IN MULTILEVEL NETWORK-CENTRIC CONTROL SYSTEMS OF REGIONAL SECURITY: APPROACH AND FORMAL MODEL

Directory of Open Access Journals (Sweden)

A. V. Masloboev

2015-01-01

Full Text Available The paper deals with development of methods and tools for mathematical and computer modeling of the multilevel network-centric control systems of regional security. This research is carried out under development strategy implementation of the Arctic zone of the Russian Federation and national safeguarding for the period before 2020 in the Murmansk region territory. Creation of unified interdepartmental multilevel computer-aided system is proposed intended for decision-making information support and socio-economic security monitoring of the Arctic regions of Russia. The distinctive features of the investigated system class are openness, self-organization, decentralization of management functions and decision-making, weak hierarchy in the decision-making circuit and goal generation capability inside itself. Research techniques include functional-target approach, mathematical apparatus of multilevel hierarchical system theory and principles of network-centric control of distributed systems with pro-active components and variable structure. The work considers network-centric management local decisions coordination problem-solving within the multilevel distributed systems intended for information support of regional security. The coordination problem-solving approach and problem formalization in the multilevel network-centric control systems of regional security have been proposed based on developed multilevel recurrent hierarchical model of regional socio-economic system complex security. The model provides coordination of regional security indexes, optimized by the different elements of multilevel control systems, subject to decentralized decision-making. The model specificity consists in application of functional-target technology and mathematical apparatus of multilevel hierarchical system theory for coordination procedures implementation of the network-centric management local decisions. The work-out and research results can find further

Using LOTOS for Formalizing Wireless Sensor Network Applications

Science.gov (United States)

Rosa, Nelson Souto; Cunha, Paulo Roberto Freire

2007-01-01

The number of wireless sensor network (WSN) applications is rapidly increasing and becoming an integral part of sensor nodes. These applications have been widely developed on TinyOS operating system using the nesC programming language. However, due to the tight integration to physical world, limited node power and resources (CPU and memory) and complexity of combining components into an application, to build such applications is not a trivial task. In this context, we present an approach for treating with this complexity adopting a formal description technique, namely LOTOS, for formalising the WSN applications ‘behaviour. The formalisation has three main benefits: better understanding on how the application actually works, checking of desired properties of the application's behaviour, and simulation facilities. In order to illustrate the proposed approach, we apply it to two nesC traditional applications, namely BLink and Sense.

Application of different entropy formalisms in a neural network for novel word learning

Science.gov (United States)

Khordad, R.; Rastegar Sedehi, H. R.

2015-12-01

In this paper novel word learning in adults is studied. For this goal, four entropy formalisms are employed to include some degree of non-locality in a neural network. The entropy formalisms are Tsallis, Landsberg-Vedral, Kaniadakis, and Abe entropies. First, we have analytically obtained non-extensive cost functions for the all entropies. Then, we have used a generalization of the gradient descent dynamics as a learning rule in a simple perceptron. The Langevin equations are numerically solved and the error function (learning curve) is obtained versus time for different values of the parameters. The influence of index q and number of neuron N on learning is investigated for the all entropies. It is found that learning is a decreasing function of time for the all entropies. The rate of learning for the Landsberg-Vedral entropy is slower than other entropies. The variation of learning with time for the Landsberg-Vedral entropy is not appreciable when the number of neurons increases. It is said that entropy formalism can be used as a means for studying the learning.

Capacity planning of link restorable optical networks under dynamic change of traffic

Science.gov (United States)

Ho, Kwok Shing; Cheung, Kwok Wai

2005-11-01

Future backbone networks shall require full-survivability and support dynamic changes of traffic demands. The Generalized Survivable Networks (GSN) was proposed to meet these challenges. GSN is fully-survivable under dynamic traffic demand changes, so it offers a practical and guaranteed characterization framework for ASTN / ASON survivable network planning and bandwidth-on-demand resource allocation 4. The basic idea of GSN is to incorporate the non-blocking network concept into the survivable network models. In GSN, each network node must specify its I/O capacity bound which is taken as constraints for any allowable traffic demand matrix. In this paper, we consider the following generic GSN network design problem: Given the I/O bounds of each network node, find a routing scheme (and the corresponding rerouting scheme under failure) and the link capacity assignment (both working and spare) which minimize the cost, such that any traffic matrix consistent with the given I/O bounds can be feasibly routed and it is single-fault tolerant under the link restoration scheme. We first show how the initial, infeasible formal mixed integer programming formulation can be transformed into a more feasible problem using the duality transformation of the linear program. Then we show how the problem can be simplified using the Lagrangian Relaxation approach. Previous work has outlined a two-phase approach for solving this problem where the first phase optimizes the working capacity assignment and the second phase optimizes the spare capacity assignment. In this paper, we present a jointly optimized framework for dimensioning the survivable optical network with the GSN model. Experiment results show that the jointly optimized GSN can bring about on average of 3.8% cost savings when compared with the separate, two-phase approach. Finally, we perform a cost comparison and show that GSN can be deployed with a reasonable cost.

Unpacking (In)formal Learning in an Academic Development Programme: A Mixed-Method Social Network Perspective

Science.gov (United States)

Rienties, Bart; Hosein, Anesa

2015-01-01

How and with whom academics develop and maintain formal and informal networks for reflecting on their teaching practice has received limited attention even though academic development (AD) programmes have become an almost ubiquitous feature of higher education. The primary goal of this mixed-method study is to unpack how 114 academics in an AD…

Hybrid optical CDMA-FSO communications network under spatially correlated gamma-gamma scintillation.

Science.gov (United States)

Jurado-Navas, Antonio; Raddo, Thiago R; Garrido-Balsells, José María; Borges, Ben-Hur V; Olmos, Juan José Vegas; Monroy, Idelfonso Tafur

2016-07-25

In this paper, we propose a new hybrid network solution based on asynchronous optical code-division multiple-access (OCDMA) and free-space optical (FSO) technologies for last-mile access networks, where fiber deployment is impractical. The architecture of the proposed hybrid OCDMA-FSO network is thoroughly described. The users access the network in a fully asynchronous manner by means of assigned fast frequency hopping (FFH)-based codes. In the FSO receiver, an equal gain-combining technique is employed along with intensity modulation and direct detection. New analytical formalisms for evaluating the average bit error rate (ABER) performance are also proposed. These formalisms, based on the spatially correlated gamma-gamma statistical model, are derived considering three distinct scenarios, namely, uncorrelated, totally correlated, and partially correlated channels. Numerical results show that users can successfully achieve error-free ABER levels for the three scenarios considered as long as forward error correction (FEC) algorithms are employed. Therefore, OCDMA-FSO networks can be a prospective alternative to deliver high-speed communication services to access networks with deficient fiber infrastructure.

Robustness of networks against propagating attacks under vaccination strategies

International Nuclear Information System (INIS)

Hasegawa, Takehisa; Masuda, Naoki

2011-01-01

We study the effect of vaccination on the robustness of networks against propagating attacks that obey the susceptible–infected–removed model. By extending the generating function formalism developed by Newman (2005 Phys. Rev. Lett. 95 108701), we analytically determine the robustness of networks that depends on the vaccination parameters. We consider the random defense where nodes are vaccinated randomly and the degree-based defense where hubs are preferentially vaccinated. We show that, when vaccines are inefficient, the random graph is more robust against propagating attacks than the scale-free network. When vaccines are relatively efficient, the scale-free network with the degree-based defense is more robust than the random graph with the random defense and the scale-free network with the random defense

Understanding the Construction of Personal Learning Networks to Support Non-Formal Workplace Learning of Training Professionals

Science.gov (United States)

Manning, Christin

2013-01-01

Workers in the 21st century workplace are faced with rapid and constant developments that place a heavy demand on them to continually learn beyond what the Human Resources and Training groups can meet. As a consequence, professionals must rely on non-formal learning approaches through the development of a personal learning network to keep…

Network Learning and Innovation in SME Formal Networks

Directory of Open Access Journals (Sweden)

Jivka Deiters

2013-02-01

Full Text Available The driver for this paper is the need to better understand the potential for learning and innovation that networks canprovide especially for small and medium sized enterprises (SMEs which comprise by far the majority of enterprises in the food sector. With the challenges the food sector is facing in the near future, learning and innovation or more focused, as it is being discussed in the paper, ‘learning for innovation’ are not just opportunities but pre‐conditions for the sustainability of the sector. Network initiatives that could provide appropriate support involve social interaction and knowledge exchange, learning, competence development, and coordination (organization and management of implementation. The analysis identifies case studies in any of these orientations which serve different stages of the innovation process: invention and implementation. The variety of network case studies cover networks linked to a focus group for training, research, orconsulting, networks dealing with focused market oriented product or process development, promotional networks, and networks for open exchange and social networking.

Toward a formalized account of attitudes: The Causal Attitude Network (CAN) model.

Science.gov (United States)

Dalege, Jonas; Borsboom, Denny; van Harreveld, Frenk; van den Berg, Helma; Conner, Mark; van der Maas, Han L J

2016-01-01

This article introduces the Causal Attitude Network (CAN) model, which conceptualizes attitudes as networks consisting of evaluative reactions and interactions between these reactions. Relevant evaluative reactions include beliefs, feelings, and behaviors toward the attitude object. Interactions between these reactions arise through direct causal influences (e.g., the belief that snakes are dangerous causes fear of snakes) and mechanisms that support evaluative consistency between related contents of evaluative reactions (e.g., people tend to align their belief that snakes are useful with their belief that snakes help maintain ecological balance). In the CAN model, the structure of attitude networks conforms to a small-world structure: evaluative reactions that are similar to each other form tight clusters, which are connected by a sparser set of "shortcuts" between them. We argue that the CAN model provides a realistic formalized measurement model of attitudes and therefore fills a crucial gap in the attitude literature. Furthermore, the CAN model provides testable predictions for the structure of attitudes and how they develop, remain stable, and change over time. Attitude strength is conceptualized in terms of the connectivity of attitude networks and we show that this provides a parsimonious account of the differences between strong and weak attitudes. We discuss the CAN model in relation to possible extensions, implication for the assessment of attitudes, and possibilities for further study. (c) 2015 APA, all rights reserved).

Formal Verification -26 ...

Indian Academy of Sciences (India)

by testing of the components and successful testing leads to the software being ... Formal verification is based on formal methods which are mathematically based ..... scenario under which a similar error could occur. There are various other ...

Reaction-diffusion-like formalism for plastic neural networks reveals dissipative solitons at criticality

Science.gov (United States)

Grytskyy, Dmytro; Diesmann, Markus; Helias, Moritz

2016-06-01

Self-organized structures in networks with spike-timing dependent synaptic plasticity (STDP) are likely to play a central role for information processing in the brain. In the present study we derive a reaction-diffusion-like formalism for plastic feed-forward networks of nonlinear rate-based model neurons with a correlation sensitive learning rule inspired by and being qualitatively similar to STDP. After obtaining equations that describe the change of the spatial shape of the signal from layer to layer, we derive a criterion for the nonlinearity necessary to obtain stable dynamics for arbitrary input. We classify the possible scenarios of signal evolution and find that close to the transition to the unstable regime metastable solutions appear. The form of these dissipative solitons is determined analytically and the evolution and interaction of several such coexistent objects is investigated.

Simulations of biopolymer networks under shear

NARCIS (Netherlands)

Huisman, Elisabeth Margaretha

2011-01-01

In this thesis we present a new method to simulate realistic three-dimensional networks of biopolymers under shear. These biopolymer networks are important for the structural functions of cells and tissues. We use the method to analyze these networks under shear, and consider the elastic modulus,

A Formal Approach to the Selection by Minimum Error and Pattern Method for Sensor Data Loss Reduction in Unstable Wireless Sensor Network Communications.

Science.gov (United States)

Kim, Changhwa; Shin, DongHyun

2017-05-12

There are wireless networks in which typically communications are unsafe. Most terrestrial wireless sensor networks belong to this category of networks. Another example of an unsafe communication network is an underwater acoustic sensor network (UWASN). In UWASNs in particular, communication failures occur frequently and the failure durations can range from seconds up to a few hours, days, or even weeks. These communication failures can cause data losses significant enough to seriously damage human life or property, depending on their application areas. In this paper, we propose a framework to reduce sensor data loss during communication failures and we present a formal approach to the Selection by Minimum Error and Pattern (SMEP) method that plays the most important role for the reduction in sensor data loss under the proposed framework. The SMEP method is compared with other methods to validate its effectiveness through experiments using real-field sensor data sets. Moreover, based on our experimental results and performance comparisons, the SMEP method has been validated to be better than others in terms of the average sensor data value error rate caused by sensor data loss.

Centrality measures and thermodynamic formalism for complex networks.

Science.gov (United States)

Delvenne, Jean-Charles; Libert, Anne-Sophie

2011-04-01

In the study of small and large networks it is customary to perform a simple random walk where the random walker jumps from one node to one of its neighbors with uniform probability. The properties of this random walk are intimately related to the combinatorial properties of the network. In this paper we propose to use the Ruelle-Bowens random walk instead, whose probability transitions are chosen in order to maximize the entropy rate of the walk on an unweighted graph. If the graph is weighted, then a free energy is optimized instead of the entropy rate. Specifically, we introduce a centrality measure for large networks, which is the stationary distribution attained by the Ruelle-Bowens random walk; we name it entropy rank. We introduce a more general version, which is able to deal with disconnected networks, under the name of free-energy rank. We compare the properties of those centrality measures with the classic PageRank and hyperlink-induced topic search (HITS) on both toy and real-life examples, in particular their robustness to small modifications of the network. We show that our centrality measures are more discriminating than PageRank, since they are able to distinguish clearly pages that PageRank regards as almost equally interesting, and are more sensitive to the medium-scale details of the graph.

Relating Lagrangian and Hamiltonian Formalisms of LC Circuits

NARCIS (Netherlands)

Clemente-Gallardo, Jesús; Scherpen, Jacquelien M.A.

2003-01-01

The Lagrangian formalism earlier defined for (switching) electrical circuits, is adapted to the Lagrangian formalism defined on Lie algebroids. This allows us to define regular Lagrangians and consequently, well-defined Hamiltonian descriptions of arbitrary LC networks. The relation with other

The connection-set algebra--a novel formalism for the representation of connectivity structure in neuronal network models.

Science.gov (United States)

Djurfeldt, Mikael

2012-07-01

The connection-set algebra (CSA) is a novel and general formalism for the description of connectivity in neuronal network models, from small-scale to large-scale structure. The algebra provides operators to form more complex sets of connections from simpler ones and also provides parameterization of such sets. CSA is expressive enough to describe a wide range of connection patterns, including multiple types of random and/or geometrically dependent connectivity, and can serve as a concise notation for network structure in scientific writing. CSA implementations allow for scalable and efficient representation of connectivity in parallel neuronal network simulators and could even allow for avoiding explicit representation of connections in computer memory. The expressiveness of CSA makes prototyping of network structure easy. A C+ + version of the algebra has been implemented and used in a large-scale neuronal network simulation (Djurfeldt et al., IBM J Res Dev 52(1/2):31-42, 2008b) and an implementation in Python has been publicly released.

Formalizing physical security procedures

NARCIS (Netherlands)

Meadows, C.; Pavlovic, Dusko

Although the problems of physical security emerged more than 10,000 years before the problems of computer security, no formal methods have been developed for them, and the solutions have been evolving slowly, mostly through social procedures. But as the traffic on physical and social networks is now

Psychologist in non-formal education

OpenAIRE

Pavićević Miljana S.

2011-01-01

Learning is not limited to school time. It starts at birth and continues throughout the entire life. Equally important as formal education there are also non-formal and informal education. Any kind of learning outside the traditional school can be called informal. However, it is not easy to define non-formal education because it is being described differently, for example as an education movement, process, system… Projects and programs implemented under the name of non-formal education are of...

Hybrid optical CDMA-FSO communications network under spatially correlated gamma-gamma scintillation

DEFF Research Database (Denmark)

Jurado-Navas, Antonio; Raddo, Thiago R.; Garrido-Balsells, José María

2016-01-01

In this paper, we propose a new hybrid network solution based on asynchronous optical code-division multiple-access (OCDMA) and free-space optical (FSO) technologies for last-mile access networks, where fiber deployment is impractical. The architecture of the proposed hybrid OCDMA-FSO network...... is thoroughly described. The users access the network in a fully asynchronous manner by means of assigned fast frequency hopping (FFH)-based codes. In the FSO receiver, an equal gain-combining technique is employed along with intensity modulation and direct detection. New analytical formalisms for evaluating...... can successfully achieve error-free ABER levels for the three scenarios considered as long as forward error correction (FEC) algorithms are employed. Therefore, OCDMA-FSO networks can be a prospective alternative to deliver high-speed communication services to access networks with deficient fiber...

Strategies for optical transport network recovery under epidemic network failures

DEFF Research Database (Denmark)

Ruepp, Sarah Renée; Fagertun, Anna Manolova; Kosteas, Vasileios

2015-01-01

The current trend in deploying automatic control plane solutions for increased flexibility in the optical transport layer leads to numerous advantages for both the operators and the customers, but also pose challenges related to the stability of the network and its ability to operate in a robust...... manner under different failure scenarios. This work evaluates two rerouting strategies and proposes four policies for failure handling in a connection-oriented optical transport network, under generalized multiprotocol label switching control plane. The performance of the strategies and the policies......, and that there exist a clear trade-off between policy performance and network resource consumption, which must be addressed by network operators for improved robustness of their transport infrastructures. Applying proactive methods for avoiding areas where epidemic failures spread results in 50% less connections...

Interspecific Competition Underlying Mutualistic Networks

Science.gov (United States)

Maeng, Seong Eun; Lee, Jae Woo; Lee, Deok-Sun

2012-03-01

Multiple classes of interactions may exist affecting one another in a given system. For the mutualistic networks of plants and pollinating animals, it has been known that the degree distribution is broad but often deviates from power-law form more significantly for plants than animals. To illuminate the origin of such asymmetry, we study a model network in which links are assigned under generalized preferential-selection rules between two groups of nodes and find the sensitive dependence of the resulting connectivity pattern on the model parameters. The nonlinearity of preferential selection can come from interspecific interactions among animals and among plants. The model-based analysis of real-world mutualistic networks suggests that a new animal determines its partners not only by their abundance but also under the competition with existing animal species, which leads to the stretched-exponential degree distributions of plants.

The Formalization of Cultural Psychology. Reasons and Functions.

Science.gov (United States)

Salvatore, Sergio

2017-03-01

In this paper I discuss two basic theses about the formalization of cultural psychology. First, I claim that formalization is a relevant, even necessary stage of development of this domain of science. This is so because formalization allows the scientific language to achieve a much needed autonomy from the commonsensical language of the phenomena that this science deals with. Second, I envisage the two main functions that formalization has to perform in the field of cultural psychology: on the one hand, it has to provide formal rules grounding and constraining the deductive construction of the general theory; on the other hand, it has to provide the devices for supporting the interpretation of local phenomena, in terms of the abductive reconstruction of the network of linkages among empirical occurrences comprising the local phenomena.

Towards a Formal Model of Social Data

DEFF Research Database (Denmark)

Mukkamala, Raghava Rao; Vatrapu, Ravi; Hussain, Abid

, transform, analyse, and report social data from social media platforms such as Facebook and twitter. Formal methods, models and tools for social data are largely limited to graph theoretical approaches informing conceptual developments in relational sociology and methodological developments in social...... network analysis. As far as we know, there are no integrated modeling approaches to social data across the conceptual, formal and software realms. Social media analytics can be undertaken in two main ways - ”Social Graph Analytics” and ”Social Text Analytics” (Vatrapu, in press/2013). Social graph......, we exemplify the semantics of the formal model with real-world social data examples. Third, we briefly present and discuss the Social Data Analytics Tool (SODATO) that realizes the conceptual model in software and provisions social data for computational social science analysis based on the formal...

The Effect of Formal Organizational Structures on Inter-organizational Networks : A study on OEMs in the forest technology industry of Northern Sweden

OpenAIRE

Maitha, Olive; Wang'oe, Robert

2013-01-01

Purpose The purpose of this research is to investigate the effects that Formal Organizational Structures have on the formation of Inter-organizational Networks Background/ Problem When organizations are formed, they tend to lack access to resources that they need for their growth and development. The owners are forced to form interactions with relatives and close friends so as to acquire the resources they need. This results in having strong network ties. However to develop they require acces...

Synchronization analysis of coloured delayed networks under ...

Indian Academy of Sciences (India)

This paper investigates synchronization of coloured delayed networks under decentralized pinning intermittent control. To begin with, the time delays are taken into account in the coloured networks. In addition, we propose a decentralized pinning intermittent control for coloured delayed networks, which is different from that ...

Digital Resource Developments for Mathematics Education Involving Homework across Formal, Non-Formal and Informal Settings

Science.gov (United States)

Radovic, Slaviša; Passey, Don

2016-01-01

The aim of this paper is to explore further an under-developed area--how drivers of curriculum, pedagogy and assessment conceptions and practices shape the creation and uses of technologically based resources to support mathematics learning across informal, non-formal and formal learning environments. The paper considers: the importance of…

Model checking mobile ad hoc networks

NARCIS (Netherlands)

Ghassemi, Fatemeh; Fokkink, Wan

2016-01-01

Modeling arbitrary connectivity changes within mobile ad hoc networks (MANETs) makes application of automated formal verification challenging. We use constrained labeled transition systems as a semantic model to represent mobility. To model check MANET protocols with respect to the underlying

How democratic are Networks?- A framework for Assessing the Democratic Effects of Networks

DEFF Research Database (Denmark)

Agger, Annika; Löfgren, Karl

: How can we assess the democratic effects of formal network mobilisation?  The article will present a tentative framework deriving criteria from both traditional democratic theory, as well as new theories on democratic governance and collaborative planning, which can be deployed for empirical studies......There has, since the end of the 1980s, been a growing interest in western democracies for formally involving citizens in various local planning activities through network governance. The overarching goal has been to increase efficiency in local planning. Equally, it has also been accompanied...... by an underlying idea of enhancing public participation and mobilising the citizens, thereby strengthening local democracy. Even though much is written about these initiatives, the actual democratic effects of these activities have been notably overlooked in the literature. Both among scholars, as well...

37 CFR 251.41 - Formal hearings.

Science.gov (United States)

2010-07-01

... ARBITRATION ROYALTY PANEL RULES AND PROCEDURES COPYRIGHT ARBITRATION ROYALTY PANEL RULES OF PROCEDURE Procedures of Copyright Arbitration Royalty Panels § 251.41 Formal hearings. (a) The formal hearings that will be conducted under the rules of this subpart are rate adjustment hearings and royalty fee...

Implementation of Integrated Service Networks under the Quebec Mental Health Reform: Facilitators and Barriers associated with Different Territorial Profiles.

Science.gov (United States)

Fleury, Marie-Josée; Grenier, Guy; Vallée, Catherine; Aubé, Denise; Farand, Lambert

2017-03-10

This study evaluates implementation of the Quebec Mental Health Reform (2005-2015), which promoted the development of integrated service networks, in 11 local service networks organized into four territorial groups according to socio-demographic characteristics and mental health services offered. Data were collected from documents concerning networks; structured questionnaires completed by 90 managers and by 16 respondent-psychiatrists; and semi-structured interviews with 102 network stakeholders. Factors associated with implementation and integration were organized according to: 1) reform characteristics; 2) implementation context; 3) organizational characteristics; and 4) integration strategies. While local networks were in a process of development and expansion, none were fully integrated at the time of the study. Facilitators and barriers to implementation and integration were primarily associated with organizational characteristics. Integration was best achieved in larger networks including a general hospital with a psychiatric department, followed by networks with a psychiatric hospital. Formalized integration strategies such as service agreements, liaison officers, and joint training reduced some barriers to implementation in networks experiencing less favourable conditions. Strategies for the implementation of healthcare reform and integrated service networks should include sustained support and training in best-practices, adequate performance indicators and resources, formalized integration strategies to improve network coordination and suitable initiatives to promote staff retention.

Formal modeling and analysis of ER-α associated Biological Regulatory Network in breast cancer

Directory of Open Access Journals (Sweden)

Samra Khalid

2016-10-01

Full Text Available Background Breast cancer (BC is one of the leading cause of death among females worldwide. The increasing incidence of BC is due to various genetic and environmental changes which lead to the disruption of cellular signaling network(s. It is a complex disease in which several interlinking signaling cascades play a crucial role in establishing a complex regulatory network. The logical modeling approach of René Thomas has been applied to analyze the behavior of estrogen receptor-alpha (ER-α associated Biological Regulatory Network (BRN for a small part of complex events that leads to BC metastasis. Methods A discrete model was constructed using the kinetic logic formalism and its set of logical parameters were obtained using the model checking technique implemented in the SMBioNet software which is consistent with biological observations. The discrete model was further enriched with continuous dynamics by converting it into an equivalent Petri Net (PN to analyze the logical parameters of the involved entities. Results In-silico based discrete and continuous modeling of ER-α associated signaling network involved in BC provides information about behaviors and gene-gene interaction in detail. The dynamics of discrete model revealed, imperative behaviors represented as cyclic paths and trajectories leading to pathogenic states such as metastasis. Results suggest that the increased expressions of receptors ER-α, IGF-1R and EGFR slow down the activity of tumor suppressor genes (TSGs such as BRCA1, p53 and Mdm2 which can lead to metastasis. Therefore, IGF-1R and EGFR are considered as important inhibitory targets to control the metastasis in BC. Conclusion The in-silico approaches allow us to increase our understanding of the functional properties of living organisms. It opens new avenues of investigations of multiple inhibitory targets (ER-α, IGF-1R and EGFR for wet lab experiments as well as provided valuable insights in the treatment of cancers

Robustness analysis of interdependent networks under multiple-attacking strategies

Science.gov (United States)

Gao, Yan-Li; Chen, Shi-Ming; Nie, Sen; Ma, Fei; Guan, Jun-Jie

2018-04-01

The robustness of complex networks under attacks largely depends on the structure of a network and the nature of the attacks. Previous research on interdependent networks has focused on two types of initial attack: random attack and degree-based targeted attack. In this paper, a deliberate attack function is proposed, where six kinds of deliberate attacking strategies can be derived by adjusting the tunable parameters. Moreover, the robustness of four types of interdependent networks (BA-BA, ER-ER, BA-ER and ER-BA) with different coupling modes (random, positive and negative correlation) is evaluated under different attacking strategies. Interesting conclusions could be obtained. It can be found that the positive coupling mode can make the vulnerability of the interdependent network to be absolutely dependent on the most vulnerable sub-network under deliberate attacks, whereas random and negative coupling modes make the vulnerability of interdependent network to be mainly dependent on the being attacked sub-network. The robustness of interdependent network will be enhanced with the degree-degree correlation coefficient varying from positive to negative. Therefore, The negative coupling mode is relatively more optimal than others, which can substantially improve the robustness of the ER-ER network and ER-BA network. In terms of the attacking strategies on interdependent networks, the degree information of node is more valuable than the betweenness. In addition, we found a more efficient attacking strategy for each coupled interdependent network and proposed the corresponding protection strategy for suppressing cascading failure. Our results can be very useful for safety design and protection of interdependent networks.

Analysis and Reduction of Complex Networks Under Uncertainty.

Energy Technology Data Exchange (ETDEWEB)

Ghanem, Roger G [University of Southern California

2014-07-31

This effort was a collaboration with Youssef Marzouk of MIT, Omar Knio of Duke University (at the time at Johns Hopkins University) and Habib Najm of Sandia National Laboratories. The objective of this effort was to develop the mathematical and algorithmic capacity to analyze complex networks under uncertainty. Of interest were chemical reaction networks and smart grid networks. The statements of work for USC focused on the development of stochastic reduced models for uncertain networks. The USC team was led by Professor Roger Ghanem and consisted of one graduate student and a postdoc. The contributions completed by the USC team consisted of 1) methodology and algorithms to address the eigenvalue problem, a problem of significance in the stability of networks under stochastic perturbations, 2) methodology and algorithms to characterize probability measures on graph structures with random flows. This is an important problem in characterizing random demand (encountered in smart grid) and random degradation (encountered in infrastructure systems), as well as modeling errors in Markov Chains (with ubiquitous relevance !). 3) methodology and algorithms for treating inequalities in uncertain systems. This is an important problem in the context of models for material failure and network flows under uncertainty where conditions of failure or flow are described in the form of inequalities between the state variables.

Some scale-free networks could be robust under selective node attacks

Science.gov (United States)

Zheng, Bojin; Huang, Dan; Li, Deyi; Chen, Guisheng; Lan, Wenfei

2011-04-01

It is a mainstream idea that scale-free network would be fragile under the selective attacks. Internet is a typical scale-free network in the real world, but it never collapses under the selective attacks of computer viruses and hackers. This phenomenon is different from the deduction of the idea above because this idea assumes the same cost to delete an arbitrary node. Hence this paper discusses the behaviors of the scale-free network under the selective node attack with different cost. Through the experiments on five complex networks, we show that the scale-free network is possibly robust under the selective node attacks; furthermore, the more compact the network is, and the larger the average degree is, then the more robust the network is; with the same average degrees, the more compact the network is, the more robust the network is. This result would enrich the theory of the invulnerability of the network, and can be used to build robust social, technological and biological networks, and also has the potential to find the target of drugs.

A Collaborative Diagonal Learning Network: The role of formal and informal professional development in elementary science reform

Science.gov (United States)

Cooke-Nieves, Natasha Anika

Science education research has consistently shown that elementary teachers have a low self-efficacy and background knowledge to teach science. When they teach science, there is a lack of field experiences and inquiry-based instruction at the elementary level due to limited resources, both material and pedagogical. This study focused on an analysis of a professional development (PD) model designed by the author known as the Collaborative Diagonal Learning Network (CDLN). The purpose of this study was to examine elementary school teacher participants pedagogical content knowledge related to their experiences in a CDLN model. The CDLN model taught formal and informal instruction using a science coach and an informal educational institution. Another purpose for this research included a theoretical analysis of the CDLN model to see if its design enabled teachers to expand their resource knowledge of available science education materials. The four-month-long study used qualitative data obtained during an in-service professional development program facilitated by a science coach and educators from a large natural history museum. Using case study as the research design, four elementary school teachers were asked to evaluate the effectiveness of their science coach and museum educator workshop sessions. During the duration of this study, semi-structured individual/group interviews and open-ended pre/post PD questionnaires were used. Other data sources included researcher field notes from lesson observations, museum field trips, audio-recorded workshop sessions, email correspondence, and teacher-created artifacts. The data were analyzed using a constructivist grounded theory approach. Themes that emerged included increased self-efficacy; increased pedagogical content knowledge; increased knowledge of museum education resources and access; creation of a professional learning community; and increased knowledge of science notebooking. Implications for formal and informal

Complex networks under dynamic repair model

Science.gov (United States)

Chaoqi, Fu; Ying, Wang; Kun, Zhao; Yangjun, Gao

2018-01-01

Invulnerability is not the only factor of importance when considering complex networks' security. It is also critical to have an effective and reasonable repair strategy. Existing research on network repair is confined to the static model. The dynamic model makes better use of the redundant capacity of repaired nodes and repairs the damaged network more efficiently than the static model; however, the dynamic repair model is complex and polytropic. In this paper, we construct a dynamic repair model and systematically describe the energy-transfer relationships between nodes in the repair process of the failure network. Nodes are divided into three types, corresponding to three structures. We find that the strong coupling structure is responsible for secondary failure of the repaired nodes and propose an algorithm that can select the most suitable targets (nodes or links) to repair the failure network with minimal cost. Two types of repair strategies are identified, with different effects under the two energy-transfer rules. The research results enable a more flexible approach to network repair.

Social Capital, Network Effects and Savings in Rural Vietnam

DEFF Research Database (Denmark)

Newman, Carol; Tarp, Finn; Van Den Broeck, Katleen

social networks in rural Vietnam can play a role in increasing formal savings where knowledge gaps exist. Networks are defined as active membership of women’s unions and the quality of networks is measured by the level of formal savings observed among group members. We find that membership of high...... quality networks leads to higher levels of saving in formal financial institutions and to higher levels of saving for productive investments as compared with other precautionary or lifecycle motives. Our results suggest that transmitting financial information through formal networks could be effective...... in increasing formal savings at grassroots level. We also conclude that ensuring information disseminated by networks is both accurate and desirable as well as important given that behavioural effects are also found in low-quality networks....

Impact of self-healing capability on network robustness

Science.gov (United States)

Shang, Yilun

2015-04-01

A wide spectrum of real-life systems ranging from neurons to botnets display spontaneous recovery ability. Using the generating function formalism applied to static uncorrelated random networks with arbitrary degree distributions, the microscopic mechanism underlying the depreciation-recovery process is characterized and the effect of varying self-healing capability on network robustness is revealed. It is found that the self-healing capability of nodes has a profound impact on the phase transition in the emergence of percolating clusters, and that salient difference exists in upholding network integrity under random failures and intentional attacks. The results provide a theoretical framework for quantitatively understanding the self-healing phenomenon in varied complex systems.

Essential competencies analysis of a training model development for non-formal vocational teachers under the office of the non-formal and informal education in Thailand

Directory of Open Access Journals (Sweden)

Chayanopparat Piyanan

2016-01-01

Full Text Available Non-formal vocational education provides practical experiences in a particular occupational field to non-formal semi-skilled learners. Non-formal vocational teachers are the key persons to deliver particular occupational knowledge. The essential competencies enhancement for non-sformal vocational teachers will improve teaching performance. The question of the research is what the essential competencies for the nonformal vocational teachers are. The research method was 1 to review related literature, 2 to collect a needs assessment, and 3 to analyse the essential competencies for non-formal vocational teachers. The population includes non-formal vocational teachers at the executive level and nonformal vocational teachers. The results from the essential competencies analysis found that the essential competencies for non-formal vocational teachers consist of 5 capabilities including 1 Adult learning design capability, 2 Adult learning principle application capability, 3 ICT searching capability for teaching preparation, 4 Instructional plan development capability and 5 Instructional media development capability.

Reliability of lifeline networks under seismic hazard

International Nuclear Information System (INIS)

Selcuk, A. Sevtap; Yuecemen, M. Semih

1999-01-01

Lifelines, such as pipelines, transportation, communication and power transmission systems, are networks which extend spatially over large geographical regions. The quantification of the reliability (survival probability) of a lifeline under seismic threat requires attention, as the proper functioning of these systems during or after a destructive earthquake is vital. In this study, a lifeline is idealized as an equivalent network with the capacity of its elements being random and spatially correlated and a comprehensive probabilistic model for the assessment of the reliability of lifelines under earthquake loads is developed. The seismic hazard that the network is exposed to is described by a probability distribution derived by using the past earthquake occurrence data. The seismic hazard analysis is based on the 'classical' seismic hazard analysis model with some modifications. An efficient algorithm developed by Yoo and Deo (Yoo YB, Deo N. A comparison of algorithms for terminal pair reliability. IEEE Transactions on Reliability 1988; 37: 210-215) is utilized for the evaluation of the network reliability. This algorithm eliminates the CPU time and memory capacity problems for large networks. A comprehensive computer program, called LIFEPACK is coded in Fortran language in order to carry out the numerical computations. Two detailed case studies are presented to show the implementation of the proposed model

Information and knowledge flows in product development of automotive industry – a comparison between formal and informal networks

Directory of Open Access Journals (Sweden)

Renelson Ribeiro Sampaio

2013-03-01

Full Text Available To maintain competitive advantage, companies must innovate. Thus, high quality, low cost and diversity of products became the starting condition for competitiveness. As a result, speed and flexibility in the design of new products are crucial, as these factors are related to the ability of companies to respond adequately to the pressures from the market. Innovation is usually related to the introduction of something new in a particular work process, which lead to new products or services. The ability for people to share information is then to be seen as a factor of strengthening of the work processes in order to contribute substantially to the company's competitive advantage in this new context. Considering these aspects, this paper seeks to map the processes of product development for an automobile company, analyzing and mapping the flow of information. The main contribution of this study is the critical analysis of social network established in a time of development of a project. This analysis provides an estimate of the level of diffusion of information and knowledge among team members, as well as the comparison between social networking and formal network mapped empirically defined a priori in the company's written procedures.

Networking European Universities through e-learning (reviewed text)

OpenAIRE

Dlouhá, Jana

2008-01-01

Virtual Campus for a Sustainable Europe (VCSE) network has been selected to be part of the EC DG EAC Inventory of innovative good practice on education for sustainable development. The main purpose of the Inventory is to show concrete examples which have been implemented in the Member States under the concept of ESD in formal and non-formal learning contexts and which are at the forefront as regards innovative approaches. Projects/programmes selected as innovative good practice will be use...

The role of formal specifications

International Nuclear Information System (INIS)

McHugh, J.

1994-01-01

The role of formal requirements specification is discussed under the premise that the primary purpose of such specifications is to facilitate clear and unambiguous communications among the communities of interest for a given project. An example is presented in which the failure to reach such an understanding resulted in an accident at a chemical plant. Following the example, specification languages based on logical formalisms and notations are considered. These are rejected as failing to serve the communications needs of diverse communities. The notion of a specification as a surrogate for a program is also considered and rejected. The paper ends with a discussion of the type of formal notation that will serve the communications role and several encouraging developments are noted

Fermionic topological quantum states as tensor networks

Science.gov (United States)

Wille, C.; Buerschaper, O.; Eisert, J.

2017-06-01

Tensor network states, and in particular projected entangled pair states, play an important role in the description of strongly correlated quantum lattice systems. They do not only serve as variational states in numerical simulation methods, but also provide a framework for classifying phases of quantum matter and capture notions of topological order in a stringent and rigorous language. The rapid development in this field for spin models and bosonic systems has not yet been mirrored by an analogous development for fermionic models. In this work, we introduce a tensor network formalism capable of capturing notions of topological order for quantum systems with fermionic components. At the heart of the formalism are axioms of fermionic matrix-product operator injectivity, stable under concatenation. Building upon that, we formulate a Grassmann number tensor network ansatz for the ground state of fermionic twisted quantum double models. A specific focus is put on the paradigmatic example of the fermionic toric code. This work shows that the program of describing topologically ordered systems using tensor networks carries over to fermionic models.

Line and lattice networks under deterministic interference models

NARCIS (Netherlands)

Goseling, Jasper; Gastpar, Michael; Weber, Jos H.

Capacity bounds are compared for four different deterministic models of wireless networks, representing four different ways of handling broadcast and superposition in the physical layer. In particular, the transport capacity under a multiple unicast traffic pattern is studied for a 1-D network of

On the Equivalence of Formal Grammars and Machines.

Science.gov (United States)

Lund, Bruce

1991-01-01

Explores concepts of formal language and automata theory underlying computational linguistics. A computational formalism is described known as a "logic grammar," with which computational systems process linguistic data, with examples in declarative and procedural semantics and definite clause grammars. (13 references) (CB)

Nonlinear signal processing using neural networks: Prediction and system modelling

Energy Technology Data Exchange (ETDEWEB)

Lapedes, A.; Farber, R.

1987-06-01

The backpropagation learning algorithm for neural networks is developed into a formalism for nonlinear signal processing. We illustrate the method by selecting two common topics in signal processing, prediction and system modelling, and show that nonlinear applications can be handled extremely well by using neural networks. The formalism is a natural, nonlinear extension of the linear Least Mean Squares algorithm commonly used in adaptive signal processing. Simulations are presented that document the additional performance achieved by using nonlinear neural networks. First, we demonstrate that the formalism may be used to predict points in a highly chaotic time series with orders of magnitude increase in accuracy over conventional methods including the Linear Predictive Method and the Gabor-Volterra-Weiner Polynomial Method. Deterministic chaos is thought to be involved in many physical situations including the onset of turbulence in fluids, chemical reactions and plasma physics. Secondly, we demonstrate the use of the formalism in nonlinear system modelling by providing a graphic example in which it is clear that the neural network has accurately modelled the nonlinear transfer function. It is interesting to note that the formalism provides explicit, analytic, global, approximations to the nonlinear maps underlying the various time series. Furthermore, the neural net seems to be extremely parsimonious in its requirements for data points from the time series. We show that the neural net is able to perform well because it globally approximates the relevant maps by performing a kind of generalized mode decomposition of the maps. 24 refs., 13 figs.

The Generational Impact of Technology on Formal Writing of Rural Middle School Students

Science.gov (United States)

Land, Martha Ann

2012-01-01

The purpose of this study was to determine the impact text messages, social networks, Instant Messaging, email, and blogging had on rural middle school students' ability to decipher between formal and informal writing. Students completed self-evaluation logs, completed Formal and Informal Writing Assessments, and were scored on their use of…

Flows in networks under fuzzy conditions

CERN Document Server

Bozhenyuk, Alexander Vitalievich; Kacprzyk, Janusz; Rozenberg, Igor Naymovich

2017-01-01

This book offers a comprehensive introduction to fuzzy methods for solving flow tasks in both transportation and networks. It analyzes the problems of minimum cost and maximum flow finding with fuzzy nonzero lower flow bounds, and describes solutions to minimum cost flow finding in a network with fuzzy arc capacities and transmission costs. After a concise introduction to flow theory and tasks, the book analyzes two important problems. The first is related to determining the maximum volume for cargo transportation in the presence of uncertain network parameters, such as environmental changes, measurement errors and repair work on the roads. These parameters are represented here as fuzzy triangular, trapezoidal numbers and intervals. The second problem concerns static and dynamic flow finding in networks under fuzzy conditions, and an effective method that takes into account the network’s transit parameters is presented here. All in all, the book provides readers with a practical reference guide to state-of-...

Connection Management and Recovery Strategies under Epidemic Network Failures in Optical Transport Networks

DEFF Research Database (Denmark)

Fagertun, Anna Manolova; Ruepp, Sarah Renée

2014-01-01

The current trend in deploying automatic control plane solutions for increased flexibility in the optical transport layer leads to numerous advantages for both the operators and the customers, but also pose challenges related to the stability of the network and its ability to operate in a robust...... manner under attacks. This work proposes four policies for failure handling in a connection-oriented optical transport network, under Generalized MultiProtocol Label Switching control plane, and evaluates their performance under multiple correlated large-scale failures. We employ the Susceptible...... of their transport infrastructures. Applying proactive methods for avoiding areas where epidemic failures spread results in 50% less connections requiring recovery, which translates in improved quality of service to customers....

Formalization of Hostel Management System. | Obi | Journal of the ...

African Journals Online (AJOL)

HMS) can invariably contribute greatly to the success, profitability and customerbased approach of such an organization. The use of formal specification creates a formal approach for specifying the underlying functions and properties of the ...

Essential competencies analysis of a training model development for non-formal vocational teachers under the office of the non-formal and informal education in Thailand

OpenAIRE

Chayanopparat Piyanan; Charungkaittikul Suwithida; Ratana-Ubol Archanya

2016-01-01

Non-formal vocational education provides practical experiences in a particular occupational field to non-formal semi-skilled learners. Non-formal vocational teachers are the key persons to deliver particular occupational knowledge. The essential competencies enhancement for non-sformal vocational teachers will improve teaching performance. The question of the research is what the essential competencies for the nonformal vocational teachers are. The research method was 1) to review related lit...

Copula-based modeling of degree-correlated networks

International Nuclear Information System (INIS)

Raschke, Mathias; Schläpfer, Markus; Trantopoulos, Konstantinos

2014-01-01

Dynamical processes on complex networks such as information exchange, innovation diffusion, cascades in financial networks or epidemic spreading are highly affected by their underlying topologies as characterized by, for instance, degree–degree correlations. Here, we introduce the concept of copulas in order to generate random networks with an arbitrary degree distribution and a rich a priori degree–degree correlation (or ‘association’) structure. The accuracy of the proposed formalism and corresponding algorithm is numerically confirmed, while the method is tested on a real-world network of yeast protein–protein interactions. The derived network ensembles can be systematically deployed as proper null models, in order to unfold the complex interplay between the topology of real-world networks and the dynamics on top of them. (paper)

Formalization of the partnering structure for networked businesses

NARCIS (Netherlands)

Santana Tapia, R.G.; Zarvic, N.

2007-01-01

Rapidly changing market demands and increasing competitive pressure cause many businesses implement changes to the way they conduct business. One of these changes is the decision to collaborate with other businesses, forming what we call a 'networked business'. Networked businesses are formed by

Asymptotic stability of a genetic network under impulsive control

International Nuclear Information System (INIS)

Li Fangfei; Sun Jitao

2010-01-01

The study of the stability of genetic network is an important motif for the understanding of the living organism at both molecular and cellular levels. In this Letter, we provide a theoretical method for analyzing the asymptotic stability of a genetic network under impulsive control. And the sufficient conditions of its asymptotic stability under impulsive control are obtained. Finally, an example is given to illustrate the effectiveness of the obtained method.

Formality theory from Poisson structures to deformation quantization

CERN Document Server

Esposito, Chiara

2015-01-01

This book is a survey of the theory of formal deformation quantization of Poisson manifolds, in the formalism developed by Kontsevich. It is intended as an educational introduction for mathematical physicists who are dealing with the subject for the first time. The main topics covered are the theory of Poisson manifolds, star products and their classification, deformations of associative algebras and the formality theorem. Readers will also be familiarized with the relevant physical motivations underlying the purely mathematical construction.

Using formal specification in the Guidance and Control Software (GCS) experiment. Formal design and verification technology for life critical systems

Science.gov (United States)

Weber, Doug; Jamsek, Damir

1994-01-01

The goal of this task was to investigate how formal methods could be incorporated into a software engineering process for flight-control systems under DO-178B and to demonstrate that process by developing a formal specification for NASA's Guidance and Controls Software (GCS) Experiment. GCS is software to control the descent of a spacecraft onto a planet's surface. The GCS example is simplified from a real example spacecraft, but exhibits the characteristics of realistic spacecraft control software. The formal specification is written in Larch.

Robust Optimization of Fourth Party Logistics Network Design under Disruptions

Directory of Open Access Journals (Sweden)

Jia Li

2015-01-01

Full Text Available The Fourth Party Logistics (4PL network faces disruptions of various sorts under the dynamic and complex environment. In order to explore the robustness of the network, the 4PL network design with consideration of random disruptions is studied. The purpose of the research is to construct a 4PL network that can provide satisfactory service to customers at a lower cost when disruptions strike. Based on the definition of β-robustness, a robust optimization model of 4PL network design under disruptions is established. Based on the NP-hard characteristic of the problem, the artificial fish swarm algorithm (AFSA and the genetic algorithm (GA are developed. The effectiveness of the algorithms is tested and compared by simulation examples. By comparing the optimal solutions of the 4PL network for different robustness level, it is indicated that the robust optimization model can evade the market risks effectively and save the cost in the maximum limit when it is applied to 4PL network design.

Static analysis of topology-dependent broadcast networks

DEFF Research Database (Denmark)

Nanz, Sebastian; Nielson, Flemming; Nielson, Hanne Riis

2010-01-01

changing network topology is a crucial ingredient. In this paper, we develop a static analysis that automatically constructs an abstract transition system, labelled by actions and connectivity information, to yield a mobility-preserving finite abstraction of the behaviour of a network expressed......Broadcast semantics poses significant challenges over point-to-point communication when it comes to formal modelling and analysis. Current approaches to analysing broadcast networks have focused on fixed connectivities, but this is unsuitable in the case of wireless networks where the dynamically...... in a process calculus with asynchronous local broadcast. Furthermore, we use model checking based on a 3-valued temporal logic to distinguish network behaviour which differs under changing connectivity patterns. (C) 2009 Elsevier Inc. All rights reserved....

Energy network dispatch optimization under emergency of local energy shortage

International Nuclear Information System (INIS)

Cai, Tianxing; Zhao, Chuanyu; Xu, Qiang

2012-01-01

The consequence of short-time energy shortage under extreme conditions, such as earthquake, tsunami, and hurricane, may cause local areas to suffer from delayed rescues, widespread power outages, tremendous economic losses, and even public safety threats. In such urgent events of local energy shortage, agile energy dispatching through an effective energy transportation network, targeting the minimum energy recovery time, should be a top priority. In this paper, a novel methodology is developed for energy network dispatch optimization under emergency of local energy shortage, which includes four stages of work. First, emergency-area-centered energy network needs to be characterized, where the capacity, quantity, and availability of various energy sources are determined. Second, the energy initial situation under emergency conditions needs to be identified. Then, the energy dispatch optimization is conducted based on a developed MILP (mixed-integer linear programming) model in the third stage. Finally, the sensitivity of the minimum dispatch time with respect to uncertainty parameters is characterized by partitioning the entire space of uncertainty parameters into multiple subspaces. The efficacy of the developed methodology is demonstrated via a case study with in-depth discussions. -- Highlights: ► Address the energy network dispatch problem under emergency of local energy shortage. ► Minimize the energy restoration time for the entire energy network under emergency events. ► Develop a new MILP model and a sensitivity analysis method with respect to uncertainties.

INTERCULTURAL ISSUES IN FORMAL PARTNERSHIPS - DIAGNOSIS AND SOLUTIONS

Directory of Open Access Journals (Sweden)

Irina MANOLESCU

2014-04-01

Full Text Available Today, collaboration, information and resource sharing with different (and sometimes even competing organizations have been viewed as key for success building. Encouraged by the European and national institutions, formal partnerships, whether temporary or permanent, such as grant writing agreements, clusters, regional working groups or networks have become more widespread in the socio-economic environment. This paper aims to investigate the most important intercultural issues in various types of formal partnerships built in Romanian public and private organizations and to identify solutions to these problems. In order to provide a solid, research-based approach to our study, we studied the evaluation reports of programs and projects involving partnerships and conducted interviews with people involved in the development and implementation of joint activities. The application of results is straightforward: the organizations will raise their awareness of the importance of an intercultural analysis when participating in a formal partnership and will take into account the implementation of appropriate methods in order to overcome intercultural challenges.

The global structure of knowledge network

NARCIS (Netherlands)

Angelopoulos, Spyros; Lomi, Alessandro

2017-01-01

In this paper, we treat patent citations as knowledge networks connecting pieces of formalized knowledge and people, and focus on how ideas are connected, rather than how they are protected. We focus on the global structural properties of formalized knowledge network, and more specifically on the

Framework for integration of informal waste management sector with the formal sector in Pakistan.

Science.gov (United States)

Masood, Maryam; Barlow, Claire Y

2013-10-01

Historically, waste pickers around the globe have utilised urban solid waste as a principal source of livelihood. Formal waste management sectors usually perceive the informal waste collection/recycling networks as backward, unhygienic and generally incompatible with modern waste management systems. It is proposed here that through careful planning and administration, these seemingly troublesome informal networks can be integrated into formal waste management systems in developing countries, providing mutual benefits. A theoretical framework for integration based on a case study in Lahore, Pakistan, is presented. The proposed solution suggests that the municipal authority should draw up and agree on a formal work contract with the group of waste pickers already operating in the area. The proposed system is assessed using the integration radar framework to classify and analyse possible intervention points between the sectors. The integration of the informal waste workers with the formal waste management sector is not a one dimensional or single step process. An ideal solution might aim for a balanced focus on all four categories of intervention, although this may be influenced by local conditions. Not all the positive benefits will be immediately apparent, but it is expected that as the acceptance of such projects increases over time, the informal recycling economy will financially supplement the formal system in many ways.

Information Diffusion in Facebook-Like Social Networks Under Information Overload

Science.gov (United States)

Li, Pei; Xing, Kai; Wang, Dapeng; Zhang, Xin; Wang, Hui

2013-07-01

Research on social networks has received remarkable attention, since many people use social networks to broadcast information and stay connected with their friends. However, due to the information overload in social networks, it becomes increasingly difficult for users to find useful information. This paper takes Facebook-like social networks into account, and models the process of information diffusion under information overload. The term view scope is introduced to model the user information-processing capability under information overload, and the average number of times a message appears in view scopes after it is generated is proposed to characterize the information diffusion efficiency. Through theoretical analysis, we find that factors such as network structure and view scope number have no impact on the information diffusion efficiency, which is a surprising result. To verify the results, we conduct simulations and provide the simulation results, which are consistent with the theoretical analysis results perfectly.

Formal matrices

CERN Document Server

Krylov, Piotr

2017-01-01

This monograph is a comprehensive account of formal matrices, examining homological properties of modules over formal matrix rings and summarising the interplay between Morita contexts and K theory. While various special types of formal matrix rings have been studied for a long time from several points of view and appear in various textbooks, for instance to examine equivalences of module categories and to illustrate rings with one-sided non-symmetric properties, this particular class of rings has, so far, not been treated systematically. Exploring formal matrix rings of order 2 and introducing the notion of the determinant of a formal matrix over a commutative ring, this monograph further covers the Grothendieck and Whitehead groups of rings. Graduate students and researchers interested in ring theory, module theory and operator algebras will find this book particularly valuable. Containing numerous examples, Formal Matrices is a largely self-contained and accessible introduction to the topic, assuming a sol...

Lifelong Competence Development: On the Advantages of Formal Competence-Performance Modeling

NARCIS (Netherlands)

Kickmeier-Rust, Michael D.; Albert, Dietrich; Steiner, Christina

2006-01-01

Please, cite this publication as: Kickmeier-Rust, M.D., Albert, D., & Steiner, C. (2006). Lifelong Competence Development: On the Advantages of Formal Competence-Performance Modeling. Proceedings of International Workshop in Learning Networks for Lifelong Competence Development, TENCompetence

A study on the evolution of crack networks under thermal fatigue loading

International Nuclear Information System (INIS)

Kamaya, Masayuki; Taheri, Said

2008-01-01

The crack network is a typical cracking morphology caused by thermal fatigue loading. It was pointed out that the crack network appeared under relatively small temperature fluctuations and did not grow deeply. In this study, the mechanism of evolution of crack network and its influence on crack growth was examined by numerical calculation. First, the stress field near two interacting cracks was investigated. It was shown that there are stress-concentration and stress-shielding zones around interacting cracks, and that cracks can form a network under the bi-axial stress condition. Secondly, a Monte Carlo simulation was developed in order to simulate the initiation and growth of cracks under thermal fatigue loading and the evolution of the crack network. The local stress field formed by pre-existing cracks was evaluated by the body force method and its role in the initiation and growth of cracks was considered. The simulation could simulate the evolution of the crack network and change in number of cracks observed in the experiments. It was revealed that reduction in the stress intensity factor due to stress feature in the depth direction under high cycle thermal fatigue loading plays an important role in the evolution of the crack network and that mechanical interaction between cracks in the network affects initiation rather than growth of cracks. The crack network appears only when the crack growth in the depth direction is interrupted. It was concluded that the emergence of the crack network is preferable for the structural integrity of cracked components

Formal Specification and Automatic Analysis of Business Processes under Authorization Constraints: An Action-Based Approach

Science.gov (United States)

Armando, Alessandro; Giunchiglia, Enrico; Ponta, Serena Elisa

We present an approach to the formal specification and automatic analysis of business processes under authorization constraints based on the action language \\cal{C}. The use of \\cal{C} allows for a natural and concise modeling of the business process and the associated security policy and for the automatic analysis of the resulting specification by using the Causal Calculator (CCALC). Our approach improves upon previous work by greatly simplifying the specification step while retaining the ability to perform a fully automatic analysis. To illustrate the effectiveness of the approach we describe its application to a version of a business process taken from the banking domain and use CCALC to determine resource allocation plans complying with the security policy.

Brain network response underlying decisions about abstract reinforcers.

Science.gov (United States)

Mills-Finnerty, Colleen; Hanson, Catherine; Hanson, Stephen Jose

2014-12-01

Decision making studies typically use tasks that involve concrete action-outcome contingencies, in which subjects do something and get something. No studies have addressed decision making involving abstract reinforcers, where there are no action-outcome contingencies and choices are entirely hypothetical. The present study examines these kinds of choices, as well as whether the same biases that exist for concrete reinforcer decisions, specifically framing effects, also apply during abstract reinforcer decisions. We use both General Linear Model as well as Bayes network connectivity analysis using the Independent Multi-sample Greedy Equivalence Search (IMaGES) algorithm to examine network response underlying choices for abstract reinforcers under positive and negative framing. We find for the first time that abstract reinforcer decisions activate the same network of brain regions as concrete reinforcer decisions, including the striatum, insula, anterior cingulate, and VMPFC, results that are further supported via comparison to a meta-analysis of decision making studies. Positive and negative framing activated different parts of this network, with stronger activation in VMPFC during negative framing and in DLPFC during positive, suggesting different decision making pathways depending on frame. These results were further clarified using connectivity analysis, which revealed stronger connections between anterior cingulate, insula, and accumbens during negative framing compared to positive. Taken together, these results suggest that not only do abstract reinforcer decisions rely on the same brain substrates as concrete reinforcers, but that the response underlying framing effects on abstract reinforcers also resemble those for concrete reinforcers, specifically increased limbic system connectivity during negative frames. Copyright © 2014 Elsevier Inc. All rights reserved.

How politicians and bureaucrats network

DEFF Research Database (Denmark)

Alexander, Damon; Lewis, Jenny; Considine, Mark

2011-01-01

Effective public administration relies on the passage of information through interpersonal communication networks. While we have a vast research literature concerning formal structures and roles in organizations, including public agencies and government institutions, we know far less about the flow...... of information through semiformal, voluntary interactions. In this paper we use a large survey to explore the networking patterns of politicians and bureaucrats and to compare these with the more formal structural attributes of hierarchy and functional specialization. Social network analysis and standard...

Robustness Analysis of Real Network Topologies Under Multiple Failure Scenarios

DEFF Research Database (Denmark)

Manzano, M.; Marzo, J. L.; Calle, E.

2012-01-01

on topological characteristics. Recently approaches also consider the services supported by such networks. In this paper we carry out a robustness analysis of five real backbone telecommunication networks under defined multiple failure scenarios, taking into account the consequences of the loss of established......Nowadays the ubiquity of telecommunication networks, which underpin and fulfill key aspects of modern day living, is taken for granted. Significant large-scale failures have occurred in the last years affecting telecommunication networks. Traditionally, network robustness analysis has been focused...... connections. Results show which networks are more robust in response to a specific type of failure....

CDMA coverage under mobile heterogeneous network load

NARCIS (Netherlands)

Saban, D.; van den Berg, Hans Leo; Boucherie, Richardus J.; Endrayanto, A.I.

2002-01-01

We analytically investigate coverage (determined by the uplink) under non-homogeneous and moving traffic load of third generation UMTS mobile networks. In particular, for different call assignment policies, we investigate cell breathing and the movement of the coverage gap occurring between cells

Formal and Informal Work Group Relationships With Performance: A Moderation Model Using Social

National Research Council Canada - National Science Library

Knost, Benjamin R

2006-01-01

.... This field study, conducted at a military training course, attempted to further refine this social network-performance relationship by modeling characteristics of both the formal and informal work...

Analysis of Network Topologies Underlying Ethylene Growth Response Kinetics

Directory of Open Access Journals (Sweden)

Aaron M. Prescott

2016-08-01

underlying ethylene signaling. Analysis of each network topology results in predictions about changes that occur in network components that can be experimentally tested to give insights into which, if either, network underlies ethylene responses.

Analysis of Network Topologies Underlying Ethylene Growth Response Kinetics.

Science.gov (United States)

Prescott, Aaron M; McCollough, Forest W; Eldreth, Bryan L; Binder, Brad M; Abel, Steven M

2016-01-01

Most models for ethylene signaling involve a linear pathway. However, measurements of seedling growth kinetics when ethylene is applied and removed have resulted in more complex network models that include coherent feedforward, negative feedback, and positive feedback motifs. The dynamical responses of the proposed networks have not been explored in a quantitative manner. Here, we explore (i) whether any of the proposed models are capable of producing growth-response behaviors consistent with experimental observations and (ii) what mechanistic roles various parts of the network topologies play in ethylene signaling. To address this, we used computational methods to explore two general network topologies: The first contains a coherent feedforward loop that inhibits growth and a negative feedback from growth onto itself (CFF/NFB). In the second, ethylene promotes the cleavage of EIN2, with the product of the cleavage inhibiting growth and promoting the production of EIN2 through a positive feedback loop (PFB). Since few network parameters for ethylene signaling are known in detail, we used an evolutionary algorithm to explore sets of parameters that produce behaviors similar to experimental growth response kinetics of both wildtype and mutant seedlings. We generated a library of parameter sets by independently running the evolutionary algorithm many times. Both network topologies produce behavior consistent with experimental observations, and analysis of the parameter sets allows us to identify important network interactions and parameter constraints. We additionally screened these parameter sets for growth recovery in the presence of sub-saturating ethylene doses, which is an experimentally-observed property that emerges in some of the evolved parameter sets. Finally, we probed simplified networks maintaining key features of the CFF/NFB and PFB topologies. From this, we verified observations drawn from the larger networks about mechanisms underlying ethylene

Generalized Network Psychometrics : Combining Network and Latent Variable Models

NARCIS (Netherlands)

Epskamp, S.; Rhemtulla, M.; Borsboom, D.

2017-01-01

We introduce the network model as a formal psychometric model, conceptualizing the covariance between psychometric indicators as resulting from pairwise interactions between observable variables in a network structure. This contrasts with standard psychometric models, in which the covariance between

Spinor formalism and complex-vector formalism of general relativity

International Nuclear Information System (INIS)

Han-ying, G.; Yong-shi, W.; Gendao, L.

1974-01-01

In this paper, using E. Cartan's exterior calculus, we give the spinor form of the structure equations, which leads naturally to the Newman--Penrose equations. Furthermore, starting from the spinor spaces and the el (2C) algebra, we construct the general complex-vector formalism of general relativity. We find that both the Cahen--Debever--Defrise complex-vector formalism and that of Brans are its special cases. Thus, the spinor formalism and the complex-vector formalism of general relativity are unified on the basis of the uni-modular group SL(2C) and its Lie algebra

Formal Ontologies and Uncertainty. In Geographical Knowledge

Directory of Open Access Journals (Sweden)

Matteo Caglioni

2014-05-01

Full Text Available Formal ontologies have proved to be a very useful tool to manage interoperability among data, systems and knowledge. In this paper we will show how formal ontologies can evolve from a crisp, deterministic framework (ontologies of hard knowledge to new probabilistic, fuzzy or possibilistic frameworks (ontologies of soft knowledge. This can considerably enlarge the application potential of formal ontologies in geographic analysis and planning, where soft knowledge is intrinsically linked to the complexity of the phenomena under study.  The paper briefly presents these new uncertainty-based formal ontologies. It then highlights how ontologies are formal tools to define both concepts and relations among concepts. An example from the domain of urban geography finally shows how the cause-to-effect relation between household preferences and urban sprawl can be encoded within a crisp, a probabilistic and a possibilistic ontology, respectively. The ontology formalism will also determine the kind of reasoning that can be developed from available knowledge. Uncertain ontologies can be seen as the preliminary phase of more complex uncertainty-based models. The advantages of moving to uncertainty-based models is evident: whether it is in the analysis of geographic space or in decision support for planning, reasoning on geographic space is almost always reasoning with uncertain knowledge of geographic phenomena.

Incorporation of formal safety assessment and Bayesian network in navigational risk estimation of the Yangtze River

International Nuclear Information System (INIS)

Zhang, D.; Yan, X.P.; Yang, Z.L.; Wall, A.; Wang, J.

2013-01-01

Formal safety assessment (FSA), as a structured and systematic risk evaluation methodology, has been increasingly and broadly used in the shipping industry around the world. Concerns have been raised as to navigational safety of the Yangtze River, China's largest and the world's busiest inland waterway. Over the last few decades, the throughput of ships in the Yangtze River has increased rapidly due to the national development of the Middle and Western parts of China. Accidents such as collisions, groundings, contacts, oil-spills and fires occur repeatedly, often causing serious consequences. In order to improve the navigational safety in the Yangtze River, this paper estimates the navigational risk of the Yangtze River using the FSA concept and a Bayesian network (BN) technique. The navigational risk model is established by considering both probability and consequences of accidents with respect to a risk matrix method, followed by a scenario analysis to demonstrate the application of the proposed model

SBME : Exploring boundaries between formal, non-formal, and informal learning

OpenAIRE

Shahoumian, Armineh; Parchoma, Gale; Saunders, Murray; Hanson, Jacky; Dickinson, Mike; Pimblett, Mark

2013-01-01

In medical education learning extends beyond university settings into practice. Non-formal and informal learning support learners’ efforts to meet externally set and learner-identified objectives. In SBME research, boundaries between formal, non-formal, and informal learning have not been widely explored. Whether SBME fits within or challenges these categories can make a contribution. Formal learning is described in relation to educational settings, planning, assessment, and accreditation. In...

Actor-Network Procedures

NARCIS (Netherlands)

Pavlovic, Dusko; Meadows, Catherine; Ramanujam, R.; Ramaswamy, Srini

2012-01-01

In this paper we propose actor-networks as a formal model of computation in heterogenous networks of computers, humans and their devices, where these new procedures run; and we introduce Procedure Derivation Logic (PDL) as a framework for reasoning about security in actor-networks, as an extension

Formal modeling of a system of chemical reactions under uncertainty.

Science.gov (United States)

Ghosh, Krishnendu; Schlipf, John

2014-10-01

We describe a novel formalism representing a system of chemical reactions, with imprecise rates of reactions and concentrations of chemicals, and describe a model reduction method, pruning, based on the chemical properties. We present two algorithms, midpoint approximation and interval approximation, for construction of efficient model abstractions with uncertainty in data. We evaluate computational feasibility by posing queries in computation tree logic (CTL) on a prototype of extracellular-signal-regulated kinase (ERK) pathway.

Formalization of Database Systems -- and a Formal Definition of {IMS}

DEFF Research Database (Denmark)

Bjørner, Dines; Løvengreen, Hans Henrik

1982-01-01

Drawing upon an analogy between Programming Language Systems and Database Systems we outline the requirements that architectural specifications of database systems must futfitl, and argue that only formal, mathematical definitions may 6atisfy these. Then we illustrate home aspects and touch upon...... come ueee of formal definitions of data models and databaee management systems. A formal model of INS will carry this discussion. Finally we survey some of the exkting literature on formal definitions of database systems. The emphasis will be on constructive definitions in the denotationul semantics...... style of the VCM: Vienna Development Nethd. The role of formal definitions in international standardiaation efforts is briefly mentioned....

Inferring the gene network underlying the branching of tomato inflorescence.

Directory of Open Access Journals (Sweden)

Laura Astola

Full Text Available The architecture of tomato inflorescence strongly affects flower production and subsequent crop yield. To understand the genetic activities involved, insight into the underlying network of genes that initiate and control the sympodial growth in the tomato is essential. In this paper, we show how the structure of this network can be derived from available data of the expressions of the involved genes. Our approach starts from employing biological expert knowledge to select the most probable gene candidates behind branching behavior. To find how these genes interact, we develop a stepwise procedure for computational inference of the network structure. Our data consists of expression levels from primary shoot meristems, measured at different developmental stages on three different genotypes of tomato. With the network inferred by our algorithm, we can explain the dynamics corresponding to all three genotypes simultaneously, despite their apparent dissimilarities. We also correctly predict the chronological order of expression peaks for the main hubs in the network. Based on the inferred network, using optimal experimental design criteria, we are able to suggest an informative set of experiments for further investigation of the mechanisms underlying branching behavior.

SELF-EFFICACY OF FORMALLY AND NON-FORMALLY TRAINED PUBLIC SECTOR TEACHERS

Directory of Open Access Journals (Sweden)

Muhammad Nadeem ANWAR

2009-07-01

Full Text Available The main objective of the study was to compare the formally and non-formally trained in-service public sector teachers’ Self-efficacy. Five hypotheses were developed describing no difference in the self-efficacy of formally and non-formally trained teachers to influence decision making, influence school resources, instructional self-efficacy, disciplinary self-efficacy and create positive school climate. Teacher Efficacy Instrument (TSES developed by Bandura (2001 consisting of thirty 9-point items was used in the study. 342 formally trained and 255 non-formally trained respondents’ questionnaires were received out of 1500 mailed. The analysis of data revealed that the formally trained public sector teachers are high in their self-efficacy on all the five categories: to influence decision making, to influence school resources, instructional self-efficacy, disciplinary self-efficacy and self-efficacy to create positive school climate.

Masses of Formal Philosophy

DEFF Research Database (Denmark)

Masses of Formal Philosophy is an outgrowth of Formal Philosophy. That book gathered the responses of some of the most prominent formal philosophers to five relatively open and broad questions initiating a discussion of metaphilosophical themes and problems surrounding the use of formal methods i...... in philosophy. Including contributions from a wide range of philosophers, Masses of Formal Philosophy contains important new responses to the original five questions.......Masses of Formal Philosophy is an outgrowth of Formal Philosophy. That book gathered the responses of some of the most prominent formal philosophers to five relatively open and broad questions initiating a discussion of metaphilosophical themes and problems surrounding the use of formal methods...

A Nondominated Genetic Algorithm Procedure for Multiobjective Discrete Network Design under Demand Uncertainty

Directory of Open Access Journals (Sweden)

Bian Changzhi

2015-01-01

Full Text Available This paper addresses the multiobjective discrete network design problem under demand uncertainty. The OD travel demands are supposed to be random variables with the given probability distribution. The problem is formulated as a bilevel stochastic optimization model where the decision maker’s objective is to minimize the construction cost, the expectation, and the standard deviation of total travel time simultaneously and the user’s route choice is described using user equilibrium model on the improved network under all scenarios of uncertain demand. The proposed model generates globally near-optimal Pareto solutions for network configurations based on the Monte Carlo simulation and nondominated sorting genetic algorithms II. Numerical experiments implemented on Nguyen-Dupuis test network show trade-offs among construction cost, the expectation, and standard deviation of total travel time under uncertainty are obvious. Investment on transportation facilities is an efficient method to improve the network performance and reduce risk under demand uncertainty, but it has an obvious marginal decreasing effect.

29 CFR 1690.306 - Formal submission in absence of consultation.

Science.gov (United States)

2010-07-01

... 29 Labor 4 2010-07-01 2010-07-01 false Formal submission in absence of consultation. 1690.306... § 1690.306 Formal submission in absence of consultation. If an initiating agency has an issuance which was already under development on or before July 1, 1978, when Executive Order 12067 became effective...

Leadership Under Challenge: Information Technology R&D in a Competitive World. An Assessment of the Federal Networking and Information Technology R&D Program

National Research Council Canada - National Science Library

Marburger, John H; Kvamme, E. F; Scalise, George; Reed, Daniel A

2007-01-01

...).That leadership is essential to U.S. economic prosperity, security, and quality of life. This report presents a formal assessment of the Federal Networking and Information Technology R&D (NITRD...

Dynamics of the cell-cycle network under genome-rewiring perturbations

International Nuclear Information System (INIS)

Katzir, Yair; Elhanati, Yuval; Braun, Erez; Averbukh, Inna

2013-01-01

The cell-cycle progression is regulated by a specific network enabling its ordered dynamics. Recent experiments supported by computational models have shown that a core of genes ensures this robust cycle dynamics. However, much less is known about the direct interaction of the cell-cycle regulators with genes outside of the cell-cycle network, in particular those of the metabolic system. Following our recent experimental work, we present here a model focusing on the dynamics of the cell-cycle core network under rewiring perturbations. Rewiring is achieved by placing an essential metabolic gene exclusively under the regulation of a cell-cycle's promoter, forcing the cell-cycle network to function under a multitasking challenging condition; operating in parallel the cell-cycle progression and a metabolic essential gene. Our model relies on simple rate equations that capture the dynamics of the relevant protein–DNA and protein–protein interactions, while making a clear distinction between these two different types of processes. In particular, we treat the cell-cycle transcription factors as limited ‘resources’ and focus on the redistribution of resources in the network during its dynamics. This elucidates the sensitivity of its various nodes to rewiring interactions. The basic model produces the correct cycle dynamics for a wide range of parameters. The simplicity of the model enables us to study the interface between the cell-cycle regulation and other cellular processes. Rewiring a promoter of the network to regulate a foreign gene, forces a multitasking regulatory load. The higher the load on the promoter, the longer is the cell-cycle period. Moreover, in agreement with our experimental results, the model shows that different nodes of the network exhibit variable susceptibilities to the rewiring perturbations. Our model suggests that the topology of the cell-cycle core network ensures its plasticity and flexible interface with other cellular processes

The Integration of Formal and Non-formal Education: The Dutch “brede school”

Directory of Open Access Journals (Sweden)

du Bois-Reymond, Manuela

2009-12-01

courses and support for under-achievers who are often students with migrant background. In both sectors, primary and secondary, it is the formal school organization with its professionals which determines the character of a BS; there is no full integration of formal and non-formal education resulting in one non-disruptive learning trajectory, nor is there the intention to go in that direction. Non-formal pedagogues are partly professionals, like youth- and social workers, partly volunteers, like parents, partly non-educational partners, like school-police, psycho-medical help or commercial leisure providers. Besides that, the BS is regarded by government educational and social policy as a potential partner and anchor for community development. It is too early to make reliable statements about the effects of the BS movement in the Netherlands concerning the educational opportunities for disadvantaged children and their families, especially those with migrant background, and combat further segregation. Evaluation studies made so far are moderately positive but also point to problems of overly bureaucratized structures and layers, lack of sufficient financial resources and, again, are uncertain about long-term effects.

Formalizing Informal Logic

Directory of Open Access Journals (Sweden)

Douglas Walton

2015-12-01

Full Text Available This paper presents a formalization of informal logic using the Carneades Argumentation System (CAS, a formal, computational model of argument that consists of a formal model of argument graphs and audiences. Conflicts between pro and con arguments are resolved using proof standards, such as preponderance of the evidence. CAS also formalizes argumentation schemes. Schemes can be used to check whether a given argument instantiates the types of argument deemed normatively appropriate for the type of dialogue.

The formal path integral and quantum mechanics

International Nuclear Information System (INIS)

Johnson-Freyd, Theo

2010-01-01

Given an arbitrary Lagrangian function on R d and a choice of classical path, one can try to define Feynman's path integral supported near the classical path as a formal power series parameterized by 'Feynman diagrams', although these diagrams may diverge. We compute this expansion and show that it is (formally, if there are ultraviolet divergences) invariant under volume-preserving changes of coordinates. We prove that if the ultraviolet divergences cancel at each order, then our formal path integral satisfies a 'Fubini theorem' expressing the standard composition law for the time evolution operator in quantum mechanics. Moreover, we show that when the Lagrangian is inhomogeneous quadratic in velocity such that its homogeneous-quadratic part is given by a matrix with constant determinant, then the divergences cancel at each order. Thus, by 'cutting and pasting' and choosing volume-compatible local coordinates, our construction defines a Feynman-diagrammatic 'formal path integral' for the nonrelativistic quantum mechanics of a charged particle moving in a Riemannian manifold with an external electromagnetic field.

Performance in wireless networks and industrial wireless networks on control processes in real time under industrial environments

Directory of Open Access Journals (Sweden)

Juan F. Monsalve-Posada

2015-01-01

Full Text Available The growing use of Ethernet networks on the industrial automation pyramid has led many companies to develop new devices to operate in requirements of this level, nowadays it is called Industrial Ethernet network, on the market there are various sensors and actuators to industrial scale equipped with this technology, many of these devices are very expensive. In this paper, the performance of two wireless networks is evaluated, the first network has conventional Ethernet devices, and the second network has Industrial Ethernet devices. For the process we vary four parameters such as distance, number of bytes, the signal to noise ratio, and the packet error rate, and then we measure delays and compare with metric statistics results, Box Plot graphs were used for the analysis. Finally, we conclude that under the parameters and conditions tested, wireless networks can serve as a communication system in control applications with allowable delays of up to 50 ms, in addition, the results show a better performance of Industrial Ethernet networks over conventional networks, with differences in the RTT of milliseconds. Therefore, it is recommended to establish what risk is for the process to control these delays to determine if the equipment conventional applies, since under certain features like humidity and temperature can operate properly for a considerable time and at lower cost than devices to Industrial Ethernet.

Modular analysis of biological networks.

Science.gov (United States)

Kaltenbach, Hans-Michael; Stelling, Jörg

2012-01-01

The analysis of complex biological networks has traditionally relied on decomposition into smaller, semi-autonomous units such as individual signaling pathways. With the increased scope of systems biology (models), rational approaches to modularization have become an important topic. With increasing acceptance of de facto modularity in biology, widely different definitions of what constitutes a module have sparked controversies. Here, we therefore review prominent classes of modular approaches based on formal network representations. Despite some promising research directions, several important theoretical challenges remain open on the way to formal, function-centered modular decompositions for dynamic biological networks.

Characterizing short-term stability for Boolean networks over any distribution of transfer functions

International Nuclear Information System (INIS)

Seshadhri, C.; Smith, Andrew M.; Vorobeychik, Yevgeniy; Mayo, Jackson R.; Armstrong, Robert C.

2016-01-01

Here we present a characterization of short-term stability of random Boolean networks under arbitrary distributions of transfer functions. Given any distribution of transfer functions for a random Boolean network, we present a formula that decides whether short-term chaos (damage spreading) will happen. We provide a formal proof for this formula, and empirically show that its predictions are accurate. Previous work only works for special cases of balanced families. Finally, it has been observed that these characterizations fail for unbalanced families, yet such families are widespread in real biological networks.

A High-Level Petri Net Framework for Genetic Regulatory Networks

Directory of Open Access Journals (Sweden)

Banks Richard

2007-12-01

Full Text Available To understand the function of genetic regulatory networks in the development of cellular systems, we must not only realise the individual network entities, but also the manner by which they interact. Multi-valued networks are a promising qualitative approach for modelling such genetic regulatory networks, however, at present they have limited formal analysis techniques and tools. We present a flexible formal framework for modelling and analysing multi-valued genetic regulatory networks using high-level Petri nets and logic minimization techniques. We demonstrate our approach with a detailed case study in which part of the genetic regulatory network responsible for the carbon starvation stress response in Escherichia coli is modelled and analysed. We then compare and contrast this multivalued model to a corresponding Boolean model and consider their formal relationship.

Computational chaos in massively parallel neural networks

Science.gov (United States)

Barhen, Jacob; Gulati, Sandeep

1989-01-01

A fundamental issue which directly impacts the scalability of current theoretical neural network models to massively parallel embodiments, in both software as well as hardware, is the inherent and unavoidable concurrent asynchronicity of emerging fine-grained computational ensembles and the possible emergence of chaotic manifestations. Previous analyses attributed dynamical instability to the topology of the interconnection matrix, to parasitic components or to propagation delays. However, researchers have observed the existence of emergent computational chaos in a concurrently asynchronous framework, independent of the network topology. Researcher present a methodology enabling the effective asynchronous operation of large-scale neural networks. Necessary and sufficient conditions guaranteeing concurrent asynchronous convergence are established in terms of contracting operators. Lyapunov exponents are computed formally to characterize the underlying nonlinear dynamics. Simulation results are presented to illustrate network convergence to the correct results, even in the presence of large delays.

The Network Structure Underlying the Earth Observation Assessment

Science.gov (United States)

Vitkin, S.; Doane, W. E. J.; Mary, J. C.

2017-12-01

The Earth Observations Assessment (EOA 2016) is a multiyear project designed to assess the effectiveness of civil earth observation data sources (instruments, sensors, models, etc.) on societal benefit areas (SBAs) for the United States. Subject matter experts (SMEs) provided input and scored how data sources inform products, product groups, key objectives, SBA sub-areas, and SBAs in an attempt to quantify the relationships between data sources and SBAs. The resulting data were processed by Integrated Applications Incorporated (IAI) using MITRE's PALMA software to create normalized relative impact scores for each of these relationships. However, PALMA processing obscures the natural network representation of the data. Any network analysis that might identify patterns of interaction among data sources, products, and SBAs is therefore impossible. Collaborating with IAI, we cleaned and recreated a network from the original dataset. Using R and Python we explore the underlying structure of the network and apply frequent itemset mining algorithms to identify groups of data sources and products that interact. We reveal interesting patterns and relationships in the EOA dataset that were not immediately observable from the EOA 2016 report and provide a basis for further exploration of the EOA network dataset.

Construction of Gene Regulatory Networks Using Recurrent Neural Networks and Swarm Intelligence.

Science.gov (United States)

Khan, Abhinandan; Mandal, Sudip; Pal, Rajat Kumar; Saha, Goutam

2016-01-01

We have proposed a methodology for the reverse engineering of biologically plausible gene regulatory networks from temporal genetic expression data. We have used established information and the fundamental mathematical theory for this purpose. We have employed the Recurrent Neural Network formalism to extract the underlying dynamics present in the time series expression data accurately. We have introduced a new hybrid swarm intelligence framework for the accurate training of the model parameters. The proposed methodology has been first applied to a small artificial network, and the results obtained suggest that it can produce the best results available in the contemporary literature, to the best of our knowledge. Subsequently, we have implemented our proposed framework on experimental (in vivo) datasets. Finally, we have investigated two medium sized genetic networks (in silico) extracted from GeneNetWeaver, to understand how the proposed algorithm scales up with network size. Additionally, we have implemented our proposed algorithm with half the number of time points. The results indicate that a reduction of 50% in the number of time points does not have an effect on the accuracy of the proposed methodology significantly, with a maximum of just over 15% deterioration in the worst case.

Vulnerability of complex networks under intentional attack with incomplete information

International Nuclear Information System (INIS)

Wu, J; Deng, H Z; Tan, Y J; Zhu, D Z

2007-01-01

We study the vulnerability of complex networks under intentional attack with incomplete information, which means that one can only preferentially attack the most important nodes among a local region of a network. The known random failure and the intentional attack are two extreme cases of our study. Using the generating function method, we derive the exact value of the critical removal fraction f c of nodes for the disintegration of networks and the size of the giant component. To validate our model and method, we perform simulations of intentional attack with incomplete information in scale-free networks. We show that the attack information has an important effect on the vulnerability of scale-free networks. We also demonstrate that hiding a fraction of the nodes information is a cost-efficient strategy for enhancing the robustness of complex networks

LOGISTIC NETWORK REGRESSION FOR SCALABLE ANALYSIS OF NETWORKS WITH JOINT EDGE/VERTEX DYNAMICS.

Science.gov (United States)

Almquist, Zack W; Butts, Carter T

2014-08-01

Change in group size and composition has long been an important area of research in the social sciences. Similarly, interest in interaction dynamics has a long history in sociology and social psychology. However, the effects of endogenous group change on interaction dynamics are a surprisingly understudied area. One way to explore these relationships is through social network models. Network dynamics may be viewed as a process of change in the edge structure of a network, in the vertex set on which edges are defined, or in both simultaneously. Although early studies of such processes were primarily descriptive, recent work on this topic has increasingly turned to formal statistical models. Although showing great promise, many of these modern dynamic models are computationally intensive and scale very poorly in the size of the network under study and/or the number of time points considered. Likewise, currently used models focus on edge dynamics, with little support for endogenously changing vertex sets. Here, the authors show how an existing approach based on logistic network regression can be extended to serve as a highly scalable framework for modeling large networks with dynamic vertex sets. The authors place this approach within a general dynamic exponential family (exponential-family random graph modeling) context, clarifying the assumptions underlying the framework (and providing a clear path for extensions), and they show how model assessment methods for cross-sectional networks can be extended to the dynamic case. Finally, the authors illustrate this approach on a classic data set involving interactions among windsurfers on a California beach.

Northern emporia and maritime networks. Modelling past communication using archaeological network analysis

DEFF Research Database (Denmark)

Sindbæk, Søren Michael

2015-01-01

preserve patterns of thisinteraction. Formal network analysis and modelling holds the potential to identify anddemonstrate such patterns, where traditional methods often prove inadequate. Thearchaeological study of communication networks in the past, however, calls for radically different analytical...... this is not a problem of network analysis, but network synthesis: theclassic problem of cracking codes or reconstructing black-box circuits. It is proposedthat archaeological approaches to network synthesis must involve a contextualreading of network data: observations arising from individual contexts, morphologies...

Fourier Series Formalization in ACL2(r

Directory of Open Access Journals (Sweden)

Cuong K. Chau

2015-09-01

Full Text Available We formalize some basic properties of Fourier series in the logic of ACL2(r, which is a variant of ACL2 that supports reasoning about the real and complex numbers by way of non-standard analysis. More specifically, we extend a framework for formally evaluating definite integrals of real-valued, continuous functions using the Second Fundamental Theorem of Calculus. Our extended framework is also applied to functions containing free arguments. Using this framework, we are able to prove the orthogonality relationships between trigonometric functions, which are the essential properties in Fourier series analysis. The sum rule for definite integrals of indexed sums is also formalized by applying the extended framework along with the First Fundamental Theorem of Calculus and the sum rule for differentiation. The Fourier coefficient formulas of periodic functions are then formalized from the orthogonality relations and the sum rule for integration. Consequently, the uniqueness of Fourier sums is a straightforward corollary. We also present our formalization of the sum rule for definite integrals of infinite series in ACL2(r. Part of this task is to prove the Dini Uniform Convergence Theorem and the continuity of a limit function under certain conditions. A key technique in our proofs of these theorems is to apply the overspill principle from non-standard analysis.

Node vulnerability of water distribution networks under cascading failures

International Nuclear Information System (INIS)

Shuang, Qing; Zhang, Mingyuan; Yuan, Yongbo

2014-01-01

Water distribution networks (WDNs) are important in modern lifeline system. Its stability and reliability are critical for guaranteeing high living quality and continuous operation of urban functions. The aim of this paper is to evaluate the nodal vulnerability of WDNs under cascading failures. Vulnerability is defined to analyze the effects of the consequent failures. A cascading failure is a step-by-step process which is quantitatively investigated by numerical simulation with intentional attack. Monitored pressures in different nodes and flows in different pipes have been used to estimate the network topological structure and the consequences of nodal failure. Based on the connectivity loss of topological structure, the nodal vulnerability has been evaluated. A load variation function is established to record the nodal failure reason and describe the relative differences between the load and the capacity. The proposed method is validated by an illustrative example. The results revealed that the network vulnerability should be evaluated with the consideration of hydraulic analysis and network topology. In the case study, 70.59% of the node failures trigger the cascading failures with different failure processes. It is shown that the cascading failures result in severe consequences in WDNs. - Highlights: • The aim of this paper is to evaluate the nodal vulnerability of water distribution networks under cascading failures. • Monitored pressures and flows have been used to estimate the network topological structure and the consequences of nodal failure. • Based on the connectivity loss of topological structure, the nodal vulnerability has been evaluated. • A load variation function is established to record the failure reason and describe the relative differences between load and capacity. • The results show that 70.59% of the node failures trigger the cascading failures with different failure processes

Network public goods with asymmetric information about cooperation preferences and network degree

NARCIS (Netherlands)

Dijkstra, Jacob; van Assen, Marcus

2013-01-01

We propose a game theoretical model of one-shot network public goods formalizing the 'closure argument' that cooperation is more frequent in denser groups or networks. Equilibrium analyses show that (i) an 'inefficiency problem' exists: players all preferring mutual cooperation need not all

Epidemic Survivability: Characterizing Networks Under Epidemic-like Failure Propagation Scenarios

DEFF Research Database (Denmark)

Manzano, Marc; Calle, Eusebi; Ripoll, Jordi

2013-01-01

Epidemics theory has been used in different contexts in order to describe the propagation of diseases, human interactions or natural phenomena. In computer science, virus spreading has been also characterized using epidemic models. Although in the past the use of epidemic models...... in telecommunication networks has not been extensively considered, nowadays, with the increasing computation capacity and complexity of operating systems of modern network devices (routers, switches, etc.), the study of possible epidemic-like failure scenarios must be taken into account. When epidemics occur......, such as in other multiple failure scenarios, identifying the level of vulnerability offered by a network is one of the main challenges. In this paper, we present epidemic survivability, a new network measure that describes the vulnerability of each node of a network under a specific epidemic intensity. Moreover...

Analysis of Formal Methods for Specification of E-Commerce Applications

Directory of Open Access Journals (Sweden)

Sadiq Ali Khan

2016-01-01

Full Text Available E-commerce based application characteristics portray elevated dynamics while incorporating decentralized nature. Extreme emphasis influencing structural design plus implementation, positions such applications highly appreciated. Significant research articles reveal that, applying formal methods addressing challenges incumbent with E-commerce based applications, contribute towards reliability and robustness obliging the system. Anticipating and designing sturdy e-process and concurrent implementation, allows application behavior extra strength against errors, frauds and hacking, minimizing program faults during application operations. Programmers find extreme difficulty guaranteeing correct processing under all circumstances, however, not impossible. Concealed flaws and errors, triggered only under unexpected and unanticipated scenarios, pilot subtle mistakes and appalling failures. Code authors utilize various formal methods for reducing these flaws. Mentioning prominent methods would include, ASM (Abstract State Machines, B-Method, z-Language, UML (Unified Modelling Language etc. This paper primarily focuses different formal methods applied while deliberating specification and verification techniques for cost effective.

Formality in Brackets

DEFF Research Database (Denmark)

Garsten, Christina; Nyqvist, Anette

Ethnographic work in formal organizations involves learning to recognize the many layers of front stage and back stage of organized life, and to bracket formality. It means to be alert to the fact that what is formal and front stage for one some actors, and in some situations, may in fact be back...... stage and informal for others. Walking the talk, donning the appropriate attire, wearing the proper suit, may be part of what is takes to figure out the code of formal organizational settings – an entrance ticket to the backstage, as it were. Oftentimes, it involves a degree of mimicry, of ‘following...... suits’ (Nyqvist 2013), and of doing ‘ethnography by failure’ (Garsten 2013). In this paper, we explore the layers of informality and formality in our fieldwork experiences among financial investors and policy experts, and discuss how to ethnographically represent embodied fieldwork practices. How do we...

Wireless Networks under a Backoff Attack: A Game Theoretical Perspective.

Science.gov (United States)

Parras, Juan; Zazo, Santiago

2018-01-30

We study a wireless sensor network using CSMA/CA in the MAC layer under a backoff attack: some of the sensors of the network are malicious and deviate from the defined contention mechanism. We use Bianchi's network model to study the impact of the malicious sensors on the total network throughput, showing that it causes the throughput to be unfairly distributed among sensors. We model this conflict using game theory tools, where each sensor is a player. We obtain analytical solutions and propose an algorithm, based on Regret Matching, to learn the equilibrium of the game with an arbitrary number of players. Our approach is validated via simulations, showing that our theoretical predictions adjust to reality.

Supply chain network design under uncertainty

DEFF Research Database (Denmark)

Govindan, Kannan; Fattahi, Mohammad; Keyvanshokooh, Esmaeil

2017-01-01

Supply chain network design (SCND) is one of the most crucial planning problems in supply chain management (SCM). Nowadays, design decisions should be viable enough to function well under complex and uncertain business environments for many years or decades. Therefore, it is essential to make...... programming, risk-averse stochastic programming, robust optimization, and fuzzy mathematical programming are explored in terms of mathematical modeling and solution approaches. Finally, the drawbacks and missing aspects of the related literature are highlighted and a list of potential issues for future...

Comparative Analysis of Human Communication Networks in Selected Formal Organizations.

Science.gov (United States)

Farace, Richard V.; Johnson, Jerome David

This paper briefly describes the organization of a "data bank" containing research on communication networks, specifies the kinds of information compiled about various network properties, discusses some specific results of the work done to date, and presents some general conclusions about the overall project and its potential advantages to…

Software Formal Inspections Guidebook

Science.gov (United States)

1993-01-01

The Software Formal Inspections Guidebook is designed to support the inspection process of software developed by and for NASA. This document provides information on how to implement a recommended and proven method for conducting formal inspections of NASA software. This Guidebook is a companion document to NASA Standard 2202-93, Software Formal Inspections Standard, approved April 1993, which provides the rules, procedures, and specific requirements for conducting software formal inspections. Application of the Formal Inspections Standard is optional to NASA program or project management. In cases where program or project management decide to use the formal inspections method, this Guidebook provides additional information on how to establish and implement the process. The goal of the formal inspections process as documented in the above-mentioned Standard and this Guidebook is to provide a framework and model for an inspection process that will enable the detection and elimination of defects as early as possible in the software life cycle. An ancillary aspect of the formal inspection process incorporates the collection and analysis of inspection data to effect continual improvement in the inspection process and the quality of the software subjected to the process.

Decoding network dynamics in cancer

DEFF Research Database (Denmark)

Linding, Rune

2014-01-01

Biological systems are composed of highly dynamic and interconnected molecular networks that drive biological decision processes. The goal of network biology is to describe, quantify and predict the information flow and functional behaviour of living systems in a formal language and with an accur......Biological systems are composed of highly dynamic and interconnected molecular networks that drive biological decision processes. The goal of network biology is to describe, quantify and predict the information flow and functional behaviour of living systems in a formal language...... and with an accuracy that parallels our characterisation of other physical systems such as Jumbo-jets. Decades of targeted molecular and biological studies have led to numerous pathway models of developmental and disease related processes. However, so far no global models have been derived from pathways, capable...

Partial Interference and Its Performance Impact on Wireless Multiple Access Networks

Directory of Open Access Journals (Sweden)

Lau WingCheong

2010-01-01

Full Text Available To determine the capacity of wireless multiple access networks, the interference among the wireless links must be accurately modeled. In this paper, we formalize the notion of the partial interference phenomenon observed in many recent wireless measurement studies and establish analytical models with tractable solutions for various types of wireless multiple access networks. In particular, we characterize the stability region of IEEE 802.11 networks under partial interference with two potentially unsaturated links numerically. We also provide a closed-form solution for the stability region of slotted ALOHA networks under partial interference with two potentially unsaturated links and obtain a partial characterization of the boundary of the stability region for the general M-link case. Finally, we derive a closed-form approximated solution for the stability region for general M-link slotted ALOHA system under partial interference effects. Based on our results, we demonstrate that it is important to model the partial interference effects while analyzing wireless multiple access networks. This is because such considerations can result in not only significant quantitative differences in the predicted system capacity but also fundamental qualitative changes in the shape of the stability region of the systems.

Formal, Non-Formal and Informal Learning in the Sciences

Science.gov (United States)

Ainsworth, Heather L.; Eaton, Sarah Elaine

2010-01-01

This research report investigates the links between formal, non-formal and informal learning and the differences between them. In particular, the report aims to link these notions of learning to the field of sciences and engineering in Canada and the United States, including professional development of adults working in these fields. It offers…

Wireless Networks under a Backoff Attack: A Game Theoretical Perspective

Directory of Open Access Journals (Sweden)

Juan Parras

2018-01-01

Full Text Available We study a wireless sensor network using CSMA/CA in the MAC layer under a backoff attack: some of the sensors of the network are malicious and deviate from the defined contention mechanism. We use Bianchi’s network model to study the impact of the malicious sensors on the total network throughput, showing that it causes the throughput to be unfairly distributed among sensors. We model this conflict using game theory tools, where each sensor is a player. We obtain analytical solutions and propose an algorithm, based on Regret Matching, to learn the equilibrium of the game with an arbitrary number of players. Our approach is validated via simulations, showing that our theoretical predictions adjust to reality.

Fear of the Formal

DEFF Research Database (Denmark)

du Gay, Paul; Lopdrup-Hjorth, Thomas

Over recent decades, institutions exhibiting high degrees of formality have come in for severe criticism. From the private to the public sector, and across a whole spectrum of actors spanning from practitioners to academics, formal organization is viewed with increasing doubt and skepticism....... In a “Schumpetarian world” (Teece et al., 1997: 509) of dynamic competition and incessant reform, formal organization appears as well suited to survival as a fish out of water. Indeed, formal organization, and its closely overlapping semantic twin bureaucracy, are not only represented as ill suited to the realities...... is that formal organization is an obstacle to be overcome. For that very reason, critics, intellectuals and reformers alike have urged public and private organizations to break out of the stifling straightjacket of formality, to dispense with bureaucracy, and to tear down hierarchies. This could either be done...

Molecular clock on a neutral network.

Science.gov (United States)

Raval, Alpan

2007-09-28

The number of fixed mutations accumulated in an evolving population often displays a variance that is significantly larger than the mean (the overdispersed molecular clock). By examining a generic evolutionary process on a neutral network of high-fitness genotypes, we establish a formalism for computing all cumulants of the full probability distribution of accumulated mutations in terms of graph properties of the neutral network, and use the formalism to prove overdispersion of the molecular clock. We further show that significant overdispersion arises naturally in evolution when the neutral network is highly sparse, exhibits large global fluctuations in neutrality, and small local fluctuations in neutrality. The results are also relevant for elucidating aspects of neutral network topology from empirical measurements of the substitution process.

"Newbies" and "Celebrities": Detecting Social Roles in an Online Network of Teachers via Participation Patterns

Science.gov (United States)

Smith Risser, H.; Bottoms, SueAnn

2014-01-01

The advent of social networking tools allows teachers to create online networks and share information. While some virtual networks have a formal structure and defined boundaries, many do not. These unstructured virtual networks are difficult to study because they lack defined boundaries and a formal structure governing leadership roles and the…

Necessity of Integral Formalism

International Nuclear Information System (INIS)

Tao Yong

2011-01-01

To describe the physical reality, there are two ways of constructing the dynamical equation of field, differential formalism and integral formalism. The importance of this fact is firstly emphasized by Yang in case of gauge field [Phys. Rev. Lett. 33 (1974) 445], where the fact has given rise to a deeper understanding for Aharonov-Bohm phase and magnetic monopole [Phys. Rev. D 12 (1975) 3845]. In this paper we shall point out that such a fact also holds in general wave function of matter, it may give rise to a deeper understanding for Berry phase. Most importantly, we shall prove a point that, for general wave function of matter, in the adiabatic limit, there is an intrinsic difference between its integral formalism and differential formalism. It is neglect of this difference that leads to an inconsistency of quantum adiabatic theorem pointed out by Marzlin and Sanders [Phys. Rev. Lett. 93 (2004) 160408]. It has been widely accepted that there is no physical difference of using differential operator or integral operator to construct the dynamical equation of field. Nevertheless, our study shows that the Schrödinger differential equation (i.e., differential formalism for wave function) shall lead to vanishing Berry phase and that the Schrödinger integral equation (i.e., integral formalism for wave function), in the adiabatic limit, can satisfactorily give the Berry phase. Therefore, we reach a conclusion: There are two ways of describing physical reality, differential formalism and integral formalism; but the integral formalism is a unique way of complete description. (general)

δ M formalism and anisotropic chaotic inflation power spectrum

Science.gov (United States)

Talebian-Ashkezari, A.; Ahmadi, N.

2018-05-01

A new analytical approach to linear perturbations in anisotropic inflation has been introduced in [A. Talebian-Ashkezari, N. Ahmadi and A.A. Abolhasani, JCAP 03 (2018) 001] under the name of δ M formalism. In this paper we apply the mentioned approach to a model of anisotropic inflation driven by a scalar field, coupled to the kinetic term of a vector field with a U(1) symmetry. The δ M formalism provides an efficient way of computing tensor-tensor, tensor-scalar as well as scalar-scalar 2-point correlations that are needed for the analysis of the observational features of an anisotropic model on the CMB. A comparison between δ M results and the tedious calculations using in-in formalism shows the aptitude of the δ M formalism in calculating accurate two point correlation functions between physical modes of the system.

Pragmatics for formal semantics

DEFF Research Database (Denmark)

Danvy, Olivier

2011-01-01

This tech talk describes how to write and how to inter-derive formal semantics for sequential programming languages. The progress reported here is (1) concrete guidelines to write each formal semantics to alleviate their proof obligations, and (2) simple calculational tools to obtain a formal...

Analytic Treatment of Deep Neural Networks Under Additive Gaussian Noise

KAUST Repository

Alfadly, Modar

2018-01-01

Despite the impressive performance of deep neural networks (DNNs) on numerous vision tasks, they still exhibit yet-to-understand uncouth behaviours. One puzzling behaviour is the reaction of DNNs to various noise attacks, where it has been shown that there exist small adversarial noise that can result in a severe degradation in the performance of DNNs. To rigorously treat this, we derive exact analytic expressions for the first and second moments (mean and variance) of a small piecewise linear (PL) network with a single rectified linear unit (ReLU) layer subject to general Gaussian input. We experimentally show that these expressions are tight under simple linearizations of deeper PL-DNNs, especially popular architectures in the literature (e.g. LeNet and AlexNet). Extensive experiments on image classification show that these expressions can be used to study the behaviour of the output mean of the logits for each class, the inter-class confusion and the pixel-level spatial noise sensitivity of the network. Moreover, we show how these expressions can be used to systematically construct targeted and non-targeted adversarial attacks. Then, we proposed a special estimator DNN, named mixture of linearizations (MoL), and derived the analytic expressions for its output mean and variance, as well. We employed these expressions to train the model to be particularly robust against Gaussian attacks without the need for data augmentation. Upon training this network on a loss that is consolidated with the derived output probabilistic moments, the network is not only robust under very high variance Gaussian attacks but is also as robust as networks that are trained with 20 fold data augmentation.

Analytic Treatment of Deep Neural Networks Under Additive Gaussian Noise

KAUST Repository

Alfadly, Modar M.

2018-04-12

Despite the impressive performance of deep neural networks (DNNs) on numerous vision tasks, they still exhibit yet-to-understand uncouth behaviours. One puzzling behaviour is the reaction of DNNs to various noise attacks, where it has been shown that there exist small adversarial noise that can result in a severe degradation in the performance of DNNs. To rigorously treat this, we derive exact analytic expressions for the first and second moments (mean and variance) of a small piecewise linear (PL) network with a single rectified linear unit (ReLU) layer subject to general Gaussian input. We experimentally show that these expressions are tight under simple linearizations of deeper PL-DNNs, especially popular architectures in the literature (e.g. LeNet and AlexNet). Extensive experiments on image classification show that these expressions can be used to study the behaviour of the output mean of the logits for each class, the inter-class confusion and the pixel-level spatial noise sensitivity of the network. Moreover, we show how these expressions can be used to systematically construct targeted and non-targeted adversarial attacks. Then, we proposed a special estimator DNN, named mixture of linearizations (MoL), and derived the analytic expressions for its output mean and variance, as well. We employed these expressions to train the model to be particularly robust against Gaussian attacks without the need for data augmentation. Upon training this network on a loss that is consolidated with the derived output probabilistic moments, the network is not only robust under very high variance Gaussian attacks but is also as robust as networks that are trained with 20 fold data augmentation.

Bayesian network modelling of upper gastrointestinal bleeding

Science.gov (United States)

Aisha, Nazziwa; Shohaimi, Shamarina; Adam, Mohd Bakri

2013-09-01

Bayesian networks are graphical probabilistic models that represent causal and other relationships between domain variables. In the context of medical decision making, these models have been explored to help in medical diagnosis and prognosis. In this paper, we discuss the Bayesian network formalism in building medical support systems and we learn a tree augmented naive Bayes Network (TAN) from gastrointestinal bleeding data. The accuracy of the TAN in classifying the source of gastrointestinal bleeding into upper or lower source is obtained. The TAN achieves a high classification accuracy of 86% and an area under curve of 92%. A sensitivity analysis of the model shows relatively high levels of entropy reduction for color of the stool, history of gastrointestinal bleeding, consistency and the ratio of blood urea nitrogen to creatinine. The TAN facilitates the identification of the source of GIB and requires further validation.

Linking communities to formal health care providers through village health teams in rural Uganda: lessons from linking social capital.

Science.gov (United States)

Musinguzi, Laban Kashaija; Turinawe, Emmanueil Benon; Rwemisisi, Jude T; de Vries, Daniel H; Mafigiri, David K; Muhangi, Denis; de Groot, Marije; Katamba, Achilles; Pool, Robert

2017-01-11

Community-based programmes, particularly community health workers (CHWs), have been portrayed as a cost-effective alternative to the shortage of health workers in low-income countries. Usually, literature emphasises how easily CHWs link and connect communities to formal health care services. There is little evidence in Uganda to support or dispute such claims. Drawing from linking social capital framework, this paper examines the claim that village health teams (VHTs), as an example of CHWs, link and connect communities with formal health care services. Data were collected through ethnographic fieldwork undertaken as part of a larger research program in Luwero District, Uganda, between 2012 and 2014. The main methods of data collection were participant observation in events organised by VHTs. In addition, a total of 91 in-depth interviews and 42 focus group discussions (FGD) were conducted with adult community members as part of the larger project. After preliminary analysis of the data, we conducted an additional six in-depth interviews and three FGD with VHTs and four FGD with community members on the role of VHTs. Key informant interviews were conducted with local government staff, health workers, local leaders, and NGO staff with health programs in Luwero. Thematic analysis was used during data analysis. The ability of VHTs to link communities with formal health care was affected by the stakeholders' perception of their roles. Community members perceive VHTs as working for and under instructions of "others", which makes them powerless in the formal health care system. One of the challenges associated with VHTs' linking roles is support from the government and formal health care providers. Formal health care providers perceived VHTs as interested in special recognition for their services yet they are not "experts". For some health workers, the introduction of VHTs is seen as a ploy by the government to control people and hide its inability to provide health

Mixed Transportation Network Design under a Sustainable Development Perspective

Directory of Open Access Journals (Sweden)

Jin Qin

2013-01-01

Full Text Available A mixed transportation network design problem considering sustainable development was studied in this paper. Based on the discretization of continuous link-grade decision variables, a bilevel programming model was proposed to describe the problem, in which sustainability factors, including vehicle exhaust emissions, land-use scale, link load, and financial budget, are considered. The objective of the model is to minimize the total amount of resources exploited under the premise of meeting all the construction goals. A heuristic algorithm, which combined the simulated annealing and path-based gradient projection algorithm, was developed to solve the model. The numerical example shows that the transportation network optimized with the method above not only significantly alleviates the congestion on the link, but also reduces vehicle exhaust emissions within the network by up to 41.56%.

Mixed Transportation Network Design under a Sustainable Development Perspective

Science.gov (United States)

Qin, Jin; Ni, Ling-lin; Shi, Feng

2013-01-01

A mixed transportation network design problem considering sustainable development was studied in this paper. Based on the discretization of continuous link-grade decision variables, a bilevel programming model was proposed to describe the problem, in which sustainability factors, including vehicle exhaust emissions, land-use scale, link load, and financial budget, are considered. The objective of the model is to minimize the total amount of resources exploited under the premise of meeting all the construction goals. A heuristic algorithm, which combined the simulated annealing and path-based gradient projection algorithm, was developed to solve the model. The numerical example shows that the transportation network optimized with the method above not only significantly alleviates the congestion on the link, but also reduces vehicle exhaust emissions within the network by up to 41.56%. PMID:23476142

Analyzing energy consumption of wireless networks. A model-based approach

Energy Technology Data Exchange (ETDEWEB)

Yue, Haidi

2013-03-04

During the last decades, wireless networking has been continuously a hot topic both in academy and in industry. Many different wireless networks have been introduced like wireless local area networks, wireless personal networks, wireless ad hoc networks, and wireless sensor networks. If these networks want to have a long term usability, the power consumed by the wireless devices in each of these networks needs to be managed efficiently. Hence, a lot of effort has been carried out for the analysis and improvement of energy efficiency, either for a specific network layer (protocol), or new cross-layer designs. In this thesis, we apply model-based approach for the analysis of energy consumption of different wireless protocols. The protocols under consideration are: one leader election protocol, one routing protocol, and two medium access control protocols. By model-based approach we mean that all these four protocols are formalized as some formal models, more precisely, as discrete-time Markov chains (DTMCs), Markov decision processes (MDPs), or stochastic timed automata (STA). For the first two models, DTMCs and MDPs, we model them in PRISM, a prominent model checker for probabilistic model checking, and apply model checking technique to analyze them. Model checking belongs to the family of formal methods. It discovers exhaustively all possible (reachable) states of the models, and checks whether these models meet a given specification. Specifications are system properties that we want to study, usually expressed by some logics, for instance, probabilistic computer tree logic (PCTL). However, while model checking relies on rigorous mathematical foundations and automatically explores the entire state space of a model, its applicability is also limited by the so-called state space explosion problem -- even systems of moderate size often yield models with an exponentially larger state space that thwart their analysis. Hence for the STA models in this thesis, since there

Trade networks evolution under the conditions of stock market globalization

Directory of Open Access Journals (Sweden)

Kopylova Olga Volodymyrivna

2016-12-01

Full Text Available The modern perception of the stock market in terms of information technologies rapid development and under the institutionalists influence has been significantly modified and becomes multifaceted. It was detected that the main function of the market is activated, information asymmetry is minimized and more advanced financial architecture space is formed through trade networks. Formation of the modern trade networks has started on the basis of the old infrastructure, that had the highest tendency to self-organization and adaptation. The proposed architecture of trade networks of the stock market has a very clear vector of subordination – from top to bottom and has a number of positive points.

Industrial use of formal methods formal verification

CERN Document Server

Boulanger, Jean-Louis

2012-01-01

At present the literature gives students and researchers of the very general books on the formal technics. The purpose of this book is to present in a single book, a return of experience on the used of the "formal technics" (such proof and model-checking) on industrial examples for the transportation domain. This book is based on the experience of people which are completely involved in the realization and the evaluation of safety critical system software based.  The implication of the industrialists allows to raise the problems of confidentiality which could appear and so allow

Robustness of Dengue Complex Network under Targeted versus Random Attack

Directory of Open Access Journals (Sweden)

Hafiz Abid Mahmood Malik

2017-01-01

Full Text Available Dengue virus infection is one of those epidemic diseases that require much consideration in order to save the humankind from its unsafe impacts. According to the World Health Organization (WHO, 3.6 billion individuals are at risk because of the dengue virus sickness. Researchers are striving to comprehend the dengue threat. This study is a little commitment to those endeavors. To observe the robustness of the dengue network, we uprooted the links between nodes randomly and targeted by utilizing different centrality measures. The outcomes demonstrated that 5% targeted attack is equivalent to the result of 65% random assault, which showed the topology of this complex network validated a scale-free network instead of random network. Four centrality measures (Degree, Closeness, Betweenness, and Eigenvector have been ascertained to look for focal hubs. It has been observed through the results in this study that robustness of a node and links depends on topology of the network. The dengue epidemic network presented robust behaviour under random attack, and this network turned out to be more vulnerable when the hubs of higher degree have higher probability to fail. Moreover, representation of this network has been projected, and hub removal impact has been shown on the real map of Gombak (Malaysia.

Entrepreneurial networks as culturally embedded phenomena

Directory of Open Access Journals (Sweden)

Vlatka Skokic

2015-06-01

Full Text Available Entrepreneurship research concerning networks has largely focused on network structure, content and governance. We believe that further research is required in order to gain a richer understanding of why specific network forms and types originated. The purpose of this paper is to explore the existence, importance, values and meanings of both the informal and formal networks and networking behaviours of small-scale hotel owner-managers embedded in the socio-economic context of Croatia. In order to gain richer and more detailed understanding of entrepreneurial networks and to understand the influence of socio-economic setting on entrepreneurial networking, we have employed qualitative, in-depth study with small hotel owners. Results suggest that entrepreneurs do not establish strong personal and firm-to-firm ties, but rather focus on formal associations. Reported findings identify socio-cultural factors apparently unique to the context of former socialist economy which have the potential to explain the reported networking behaviour. The adopted research approach brings another dimension to existing theoretical underpinnings, which can encourage researchers to extend or revise theories with new contextual variables.

Consistence of Network Filtering Rules

Institute of Scientific and Technical Information of China (English)

SHE Kun; WU Yuancheng; HUANG Juncai; ZHOU Mingtian

2004-01-01

The inconsistence of firewall/VPN(Virtual Private Network) rule makes a huge maintainable cost.With development of Multinational Company,SOHO office,E-government the number of firewalls/VPN will increase rapidly.Rule table in stand-alone or network will be increased in geometric series accordingly.Checking the consistence of rule table manually is inadequate.A formal approach can define semantic consistence,make a theoretic foundation of intelligent management about rule tables.In this paper,a kind of formalization of host rules and network ones for auto rule-validation based on SET theory were proporsed and a rule validation scheme was defined.The analysis results show the superior performance of the methods and demonstrate its potential for the intelligent management based on rule tables.

Formal Verification and Implementation of Real-Time Applications

Directory of Open Access Journals (Sweden)

Liviu Haţegan

2009-12-01

Full Text Available This paper presents a method for the formal description, verification and automatic source code generation of embedded real-time multitasking applications, based on a model consisting of networks of timed automata. The model describes a real-time operating system kernel and application tasks, taking into consideration both non-preemptive and preemptive scheduling. The timing properties of theproposed model can be verified using a modelchecking tool. We also provide a solution for C source code generation based on the application’s model. For this purpose a unified resource access interface was implemented.

Understanding organizational congruence: formal model and simulation framework.

NARCIS (Netherlands)

Dignum, M.V.; Dignum, F.P.M.

2007-01-01

Despite a large number of studies, the effect of organizational structure on the performance and the individual cognition of its members is still not well understood. Our research aims at developing tools and formalisms to model organizations and evaluate their performance under different

Optimal Intermittent Operation of Water Distribution Networks under Water Shortage

Directory of Open Access Journals (Sweden)

mohamad Solgi

2017-07-01

Full Text Available Under water shortage conditions, it is necessary to exercise water consumption management practices in water distribution networks (WDN. Intermittent supply of water is one such practice that makes it possible to supply consumption nodal demands with the required pressure via water cutoff to some consumers during certain hours of the day. One of the most important issues that must be observed in this management practice is the equitable and uniform water distribution among the consumers. In the present study, uniformity in water distribution and minimum supply of water to all consumers are defined as justice and equity, respectively. Also, an optimization model has been developed to find an optimal intermittent supply schedule that ensures maximum number of demand nodes are supplied with water while the constraints on the operation of water distribution networks are also observed. To show the efficiency of the proposed model, it has been used in the Two-Loop distribution network under several different scenarios of water shortage. The optimization model has been solved using the honey bee mating optimization algorithm (HBMO linked to the hydraulic simulator EPANET. The results obtained confirm the efficiency of the proposed model in achieving an optimal intermittent supply schedule. Moreover, the model is found capable of distributing the available water in an equitable and just manner among all the consumers even under severe water shoratges.

Women in formal corporate networks: an organisational citizenship perspective.

OpenAIRE

Singh, Val; Vinnicombe, Susan; Kumra, Savita

2006-01-01

To investigate women's corporate networks, and the reported benefits for the women and their employers. To gain insight into the motivation for these voluntary activities, by drawing on organisational citizenship theory.

Networks and informal contract law

NARCIS (Netherlands)

Tjong Tjin Tai, Eric; Brownsword, Roger; van Gestel, Rob A.J.; Micklitz, Hans-W.

2017-01-01

It is often argued that formal contract law cannot treat networks correctly. An analysis of networks in an informal contract law system shows that informal contract law is no panacea. Remaining problems require a different approach to legal regulation and contract practice.

A Comparison of Participation Patterns in Selected Formal, Non-Formal, and Informal Online Learning Environments

Science.gov (United States)

Schwier, Richard A.; Seaton, J. X.

2013-01-01

Does learner participation vary depending on the learning context? Are there characteristic features of participation evident in formal, non-formal, and informal online learning environments? Six online learning environments were chosen as epitomes of formal, non-formal, and informal learning contexts and compared. Transcripts of online…

Formal description of the jumpstart just-in-time signaling protocol using EFSM

Science.gov (United States)

Zaim, A. H.; Baldine, Ilia; Cassada, Mark; Rouskas, George N.; Perros, Harry G.; Stevenson, Daniel S.

2002-07-01

We present a formal protocol description for a Just-In-Time (JIT) signaling scheme running over a core dWDM network which utilizes Optical Burst Switches (OBS). We apply an eight-tuple extended finite state machine (EFSM) model to formally specify the protocol. Using the EFSM model, we define the communication between a source client node and a destination client node through an ingress and one or multiple intermediate switches. We worked on single burst connections that means setting up the connection just before sending a single burst and then closing the connection as soon as the burst is sent. The communication between the EFSMs is handled through message transfer between protocol entities.

Convergence and approximate calculation of average degree under different network sizes for decreasing random birth-and-death networks

Science.gov (United States)

Long, Yin; Zhang, Xiao-Jun; Wang, Kui

2018-05-01

In this paper, convergence and approximate calculation of average degree under different network sizes for decreasing random birth-and-death networks (RBDNs) are studied. First, we find and demonstrate that the average degree is convergent in the form of power law. Meanwhile, we discover that the ratios of the back items to front items of convergent reminder are independent of network link number for large network size, and we theoretically prove that the limit of the ratio is a constant. Moreover, since it is difficult to calculate the analytical solution of the average degree for large network sizes, we adopt numerical method to obtain approximate expression of the average degree to approximate its analytical solution. Finally, simulations are presented to verify our theoretical results.

On the Conditional Entropy of Wireless Networks

DEFF Research Database (Denmark)

Coon, Justin P.; Badiu, Mihai Alin; Gündüz, Deniz

2018-01-01

The characterization of topological uncertainty in wireless networks using the formalism of graph entropy has received interest in the spatial networks community. In this paper, we develop lower bounds on the entropy of a wireless network by conditioning on potential network observables. Two appr...... a homogeneous binomial point process in this work) and the network topology....

Chronoprojective invariance of the five-dimensional Schroedinger formalism

International Nuclear Information System (INIS)

Perrin, M.; Burdet, G.; Duval, C.

1984-10-01

Invariance properties of the five-dimensional Schroedinger formalism describing a quantum test particle in the Newton-Cartan theory of gravitation are studied. The geometry which underlies these invariance properties is presented as a reduction of the 0(5,2) conformal geometry various applications are given

Improving Learner Outcomes in Lifelong Education: Formal Pedagogies in Non-Formal Learning Contexts?

Science.gov (United States)

Zepke, Nick; Leach, Linda

2006-01-01

This article explores how far research findings about successful pedagogies in formal post-school education might be used in non-formal learning contexts--settings where learning may not lead to formal qualifications. It does this by examining a learner outcomes model adapted from a synthesis of research into retention. The article first…

Group adaptation, formal darwinism and contextual analysis.

Science.gov (United States)

Okasha, S; Paternotte, C

2012-06-01

We consider the question: under what circumstances can the concept of adaptation be applied to groups, rather than individuals? Gardner and Grafen (2009, J. Evol. Biol.22: 659-671) develop a novel approach to this question, building on Grafen's 'formal Darwinism' project, which defines adaptation in terms of links between evolutionary dynamics and optimization. They conclude that only clonal groups, and to a lesser extent groups in which reproductive competition is repressed, can be considered as adaptive units. We re-examine the conditions under which the selection-optimization links hold at the group level. We focus on an important distinction between two ways of understanding the links, which have different implications regarding group adaptationism. We show how the formal Darwinism approach can be reconciled with G.C. Williams' famous analysis of group adaptation, and we consider the relationships between group adaptation, the Price equation approach to multi-level selection, and the alternative approach based on contextual analysis. © 2012 The Authors. Journal of Evolutionary Biology © 2012 European Society For Evolutionary Biology.

Propagator formalism and computer simulation of restricted diffusion behaviors of inter-molecular multiple-quantum coherences

International Nuclear Information System (INIS)

Cai Congbo; Chen Zhong; Cai Shuhui; Zhong Jianhui

2005-01-01

In this paper, behaviors of single-quantum coherences and inter-molecular multiple-quantum coherences under restricted diffusion in nuclear magnetic resonance experiments were investigated. The propagator formalism based on the loss of spin phase memory during random motion was applied to describe the diffusion-induced signal attenuation. The exact expression of the signal attenuation under the short gradient pulse approximation for restricted diffusion between two parallel plates was obtained using this propagator method. For long gradient pulses, a modified formalism was proposed. The simulated signal attenuation under the effects of gradient pulses of different width based on the Monte Carlo method agrees with the theoretical predictions. The propagator formalism and computer simulation can provide convenient, intuitive and precise methods for the study of the diffusion behaviors

Organisational adaptation in an activist network: social networks, leadership, and change in al-Muhajiroun.

Science.gov (United States)

Kenney, Michael; Horgan, John; Horne, Cale; Vining, Peter; Carley, Kathleen M; Bigrigg, Michael W; Bloom, Mia; Braddock, Kurt

2013-09-01

Social networks are said to facilitate learning and adaptation by providing the connections through which network nodes (or agents) share information and experience. Yet, our understanding of how this process unfolds in real-world networks remains underdeveloped. This paper explores this gap through a case study of al-Muhajiroun, an activist network that continues to call for the establishment of an Islamic state in Britain despite being formally outlawed by British authorities. Drawing on organisation theory and social network analysis, we formulate three hypotheses regarding the learning capacity and social network properties of al-Muhajiroun (AM) and its successor groups. We then test these hypotheses using mixed methods. Our methods combine quantitative analysis of three agent-based networks in AM measured for structural properties that facilitate learning, including connectedness, betweenness centrality and eigenvector centrality, with qualitative analysis of interviews with AM activists focusing organisational adaptation and learning. The results of these analyses confirm that al-Muhajiroun activists respond to government pressure by changing their operations, including creating new platforms under different names and adjusting leadership roles among movement veterans to accommodate their spiritual leader's unwelcome exodus to Lebanon. Simple as they are effective, these adaptations have allowed al-Muhajiroun and its successor groups to continue their activism in an increasingly hostile environment. Copyright © 2012 Elsevier Ltd and The Ergonomics Society. All rights reserved.

Redes de aprendizaje, aprendizaje en red Learning Networks, Networked Learning

Directory of Open Access Journals (Sweden)

Peter Sloep

2011-10-01

Full Text Available Las redes de aprendizaje (Learning Networks son redes sociales en línea mediante las cuales los participantes comparten información y colaboran para crear conocimiento. De esta manera, estas redes enriquecen la experiencia de aprendizaje en cualquier contexto de aprendizaje, ya sea de educación formal (en escuelas o universidades o educación no-formal (formación profesional. Aunque el concepto de aprendizaje en red suscita el interés de diferentes actores del ámbito educativo, aún existen muchos interrogantes sobre cómo debe diseñarse el aprendizaje en red para facilitar adecuadamente la educación y la formación. El artículo toma este interrogante como punto de partida, y posteriormente aborda cuestiones como la dinámica de la evolución de las redes de aprendizaje, la importancia de fomentar la confianza entre los participantes y el papel central que desempeña el perfil de usuario en la construcción de la confianza, así como el apoyo entre compañeros. Además, se elabora el proceso de diseño de una red de aprendizaje, y se describe un ejemplo en el contexto universitario. Basándonos en la investigación que actualmente se lleva a cabo en nuestro propio centro y en otros lugares, el capítulo concluye con una visión del futuro de las redes de aprendizaje.Learning Networks are on-line social networks through which users share knowledge with each other and jointly develop new knowledge. This way, Learning Networks may enrich the experience of formal, school-based learning and form a viable setting for professional development. Although networked learning enjoys an increasing interest, many questions remain on how exactly learning in such networked contexts can contribute to successful education and training. Put differently, how should networked learning be designed best to facilitate education and training? Taking this as its point of departure, the chapter addresses such issues as the dynamic evolution of Learning Networks

Similarity between community structures of different online social networks and its impact on underlying community detection

Science.gov (United States)

Fan, W.; Yeung, K. H.

2015-03-01

As social networking services are popular, many people may register in more than one online social network. In this paper we study a set of users who have accounts of three online social networks: namely Foursquare, Facebook and Twitter. Community structure of this set of users may be reflected in these three online social networks. Therefore, high correlation between these reflections and the underlying community structure may be observed. In this work, community structures are detected in all three online social networks. Also, we investigate the similarity level of community structures across different networks. It is found that they show strong correlation with each other. The similarity between different networks may be helpful to find a community structure close to the underlying one. To verify this, we propose a method to increase the weights of some connections in networks. With this method, new networks are generated to assist community detection. By doing this, value of modularity can be improved and the new community structure match network's natural structure better. In this paper we also show that the detected community structures of online social networks are correlated with users' locations which are identified on Foursquare. This information may also be useful for underlying community detection.

Review of the helicity formalism

International Nuclear Information System (INIS)

Barreiro, F.; Cerrada, M.; Fernandez, E.

1972-01-01

Our purpose in these notes has been to present a brief and general review of the helicity formalism. We begin by discussing Lorentz invariance, spin and helicity ideas, in section 1 . In section 2 we deal with the construction of relativistic states and scattering amplitudes in the helicity basis and we study their transformation properties under discrete symmetries. Finally we present some more sophisticated topics like kinematical singularities of helicity amplitudes, kinematical constraints and crossing relations 3, 4, 5 respectively. (Author) 8 refs

Combining Formal, Non-Formal and Informal Learning for Workforce Skill Development

Science.gov (United States)

Misko, Josie

2008-01-01

This literature review, undertaken for Australian Industry Group, shows how multiple variations and combinations of formal, informal and non-formal learning, accompanied by various government incentives and organisational initiatives (including job redesign, cross-skilling, multi-skilling, diversified career pathways, action learning projects,…

The role of information technologies in organization of non-formal education

Directory of Open Access Journals (Sweden)

Elkina Irina

2016-01-01

Full Text Available The authors consider the role of information technologies in realization of non-formal education in the modern information society. Cultural and leisure institutions, libraries etc. become facilitators of non-formal education. Introduction to cultural values, to the new knowledge, obtaining positive emotions attracts the representatives of various professional and social groups to this kind of education and additionally favors their familiarization with the Humanities. A large choice of new, game forms and methods of training, learners’ active participation – all this empowers non-formal education and a skill to learn and work under the conditions of redundant information is one of the most relevant in the modern society.

Understanding visualization: a formal approach using category theory and semiotics.

Science.gov (United States)

Vickers, Paul; Faith, Joe; Rossiter, Nick

2013-06-01

This paper combines the vocabulary of semiotics and category theory to provide a formal analysis of visualization. It shows how familiar processes of visualization fit the semiotic frameworks of both Saussure and Peirce, and extends these structures using the tools of category theory to provide a general framework for understanding visualization in practice, including: Relationships between systems, data collected from those systems, renderings of those data in the form of representations, the reading of those representations to create visualizations, and the use of those visualizations to create knowledge and understanding of the system under inspection. The resulting framework is validated by demonstrating how familiar information visualization concepts (such as literalness, sensitivity, redundancy, ambiguity, generalizability, and chart junk) arise naturally from it and can be defined formally and precisely. This paper generalizes previous work on the formal characterization of visualization by, inter alia, Ziemkiewicz and Kosara and allows us to formally distinguish properties of the visualization process that previous work does not.

Will electrical cyber-physical interdependent networks undergo first-order transition under random attacks?

Science.gov (United States)

Ji, Xingpei; Wang, Bo; Liu, Dichen; Dong, Zhaoyang; Chen, Guo; Zhu, Zhenshan; Zhu, Xuedong; Wang, Xunting

2016-10-01

Whether the realistic electrical cyber-physical interdependent networks will undergo first-order transition under random failures still remains a question. To reflect the reality of Chinese electrical cyber-physical system, the "partial one-to-one correspondence" interdependent networks model is proposed and the connectivity vulnerabilities of three realistic electrical cyber-physical interdependent networks are analyzed. The simulation results show that due to the service demands of power system the topologies of power grid and its cyber network are highly inter-similar which can effectively avoid the first-order transition. By comparing the vulnerability curves between electrical cyber-physical interdependent networks and its single-layer network, we find that complex network theory is still useful in the vulnerability analysis of electrical cyber-physical interdependent networks.

Networks in the news media

DEFF Research Database (Denmark)

Bro, Peter

more formal types of social networks, but also complement or even substitute social networking elsewhere, and as such this particular type of social network offers people both inside and outside the news room new potentials - and problems. This article describe the basic vision of networks in the news......When news reporters connect people in a single news story or in a series of coherent news stories they essentially construct networks in the news media. Networks through which social actors are aligned symbolically in written, visible or audible form. These socio-symbolic networks not only copy...

The Markov process admits a consistent steady-state thermodynamic formalism

Science.gov (United States)

Peng, Liangrong; Zhu, Yi; Hong, Liu

2018-01-01

The search for a unified formulation for describing various non-equilibrium processes is a central task of modern non-equilibrium thermodynamics. In this paper, a novel steady-state thermodynamic formalism was established for general Markov processes described by the Chapman-Kolmogorov equation. Furthermore, corresponding formalisms of steady-state thermodynamics for the master equation and Fokker-Planck equation could be rigorously derived in mathematics. To be concrete, we proved that (1) in the limit of continuous time, the steady-state thermodynamic formalism for the Chapman-Kolmogorov equation fully agrees with that for the master equation; (2) a similar one-to-one correspondence could be established rigorously between the master equation and Fokker-Planck equation in the limit of large system size; (3) when a Markov process is restrained to one-step jump, the steady-state thermodynamic formalism for the Fokker-Planck equation with discrete state variables also goes to that for master equations, as the discretization step gets smaller and smaller. Our analysis indicated that general Markov processes admit a unified and self-consistent non-equilibrium steady-state thermodynamic formalism, regardless of underlying detailed models.

Anatomy and histology as socially networked learning environments: some preliminary findings.

Science.gov (United States)

Hafferty, Frederic W; Castellani, Brian; Hafferty, Philip K; Pawlina, Wojciech

2013-09-01

An exploratory study to better understand the "networked" life of the medical school as a learning environment. In a recent academic year, the authors gathered data during two six-week blocks of a sequential histology and anatomy course at a U.S. medical college. An eight-item questionnaire captured different dimensions of student interactions. The student cohort/network was 48 first-year medical students. Using social network analysis (SNA), the authors focused on (1) the initial structure and the evolution of informal class networks over time, (2) how informal class networks compare to formal in-class small-group assignments in influencing student information gathering, and (3) how peer assignment of professionalism role model status is shaped more by informal than formal ties. In examining these latter two issues, the authors explored not only how formal group assignment persisted over time but also how it functioned to prevent the tendency for groupings based on gender or ethnicity. The study revealed an evolving dynamic between the formal small-group learning structure of the course blocks and the emergence of informal student networks. For example, whereas formal group membership did influence in-class questions and did prevent formation of groups of like gender and ethnicity, outside-class questions and professionalism were influenced more by informal group ties where gender and, to a much lesser extent, ethnicity influence student information gathering. The richness of these preliminary findings suggests that SNA may be a useful tool in examining an array of medical student learning encounters.

Innovations and networking fostering tourist destination development in Slovakia

Directory of Open Access Journals (Sweden)

Gajdošík Tomáš

2017-12-01

Full Text Available The paper focuses on the implementation of innovations and networking in the sector of tourism in two Slovak mountain destinations of international significance. The main objective of the paper is to identify and evaluate how innovations and networking contribute to tourist destination development in Slovakia. The implementation of institutional innovation resulted in the establishment of formal and informal networks. The developed networks consist of representatives of all sectors co-ordinating all relevant stakeholders. Formal and informal networks and the collaboration among stakeholders have launched other types of innovations in the tourism sector. The interactions and intensity of relations among stakeholders are analysed by network analysis. Destinations are compared with the network of the same size and density through quantitative network characteristics. Based on empirical research we investigate the impact of networks and innovations on tourist destination development. Due to the synergy effect of networking and implementation of multiple innovations, tourist destination development is observed.

Networked professional learning : relating the formal and the informal

NARCIS (Netherlands)

Vaessen, M.; Beemt, van den A.A.J.; Laat, de M.

2014-01-01

The increasing complexity of the workplace environment requires teachers and professionals in general to tap into their social networks, inside and outside circles of direct colleagues and collaborators, for finding appropriate knowledge and expertise. This collective process of sharing and

Bridging the Semantic Gap Between Heterogeneous Modeling Formalisms and FMI

Science.gov (United States)

2014-04-25

Naval Research Laboratory (NRL #N0013-12-1-G015), and the following companies: Bosch, National Instruments, and Toyota ). 1 of contract, these two...but only on the interconnections of the FMUs in the network). To our knowledge , the question how to create FMUs has not been formally addressed. This...unbounded length. The main characteristic of SDF is that the number of tokens that each actor consumes from its input queues and produces to its output

Beware the tail that wags the dog: informal and formal models in biology.

Science.gov (United States)

Gunawardena, Jeremy

2014-11-05

Informal models have always been used in biology to guide thinking and devise experiments. In recent years, formal mathematical models have also been widely introduced. It is sometimes suggested that formal models are inherently superior to informal ones and that biology should develop along the lines of physics or economics by replacing the latter with the former. Here I suggest to the contrary that progress in biology requires a better integration of the formal with the informal. © 2014 Gunawardena. This article is distributed by The American Society for Cell Biology under license from the author(s). Two months after publication it is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).

Beyond formalism

Science.gov (United States)

Denning, Peter J.

1991-01-01

The ongoing debate over the role of formalism and formal specifications in software features many speakers with diverse positions. Yet, in the end, they share the conviction that the requirements of a software system can be unambiguously specified, that acceptable software is a product demonstrably meeting the specifications, and that the design process can be carried out with little interaction between designers and users once the specification has been agreed to. This conviction is part of a larger paradigm prevalent in American management thinking, which holds that organizations are systems that can be precisely specified and optimized. This paradigm, which traces historically to the works of Frederick Taylor in the early 1900s, is no longer sufficient for organizations and software systems today. In the domain of software, a new paradigm, called user-centered design, overcomes the limitations of pure formalism. Pioneered in Scandinavia, user-centered design is spreading through Europe and is beginning to make its way into the U.S.

Competence Building or Destruction in Small Business Networks

DEFF Research Database (Denmark)

Neergaard, Helle; Nielsen, Kent T.

patterns than structural analysis. Based on both quantitative and qualitative data from a population of 104 networks and 557 firms, process analysis demonstrates a crucial move from first generation, artificial, formal networks to second generation, spontaneous, informal networks. Structural analysis...

Network Performance Improvement under Epidemic Failures in Optical Transport Networks

DEFF Research Database (Denmark)

Fagertun, Anna Manolova; Ruepp, Sarah Renée

2013-01-01

In this paper we investigate epidemic failure spreading in large- scale GMPLS-controlled transport networks. By evaluating the effect of the epidemic failure spreading on the network, we design several strategies for cost-effective network performance improvement via differentiated repair times....... First we identify the most vulnerable and the most strategic nodes in the network. Then, via extensive simulations we show that strategic placement of resources for improved failure recovery has better performance than randomly assigning lower repair times among the network nodes. Our OPNET simulation...... model can be used during the network planning process for facilitating cost- effective network survivability design....

Integrated formal operations plan

Energy Technology Data Exchange (ETDEWEB)

Cort, G.; Dearholt, W.; Donahue, S.; Frank, J.; Perkins, B.; Tyler, R.; Wrye, J.

1994-01-05

The concept of formal operations (that is, a collection of business practices to assure effective, accountable operations) has vexed the Laboratory for many years. To date most attempts at developing such programs have been based upon rigid, compliance-based interpretations of a veritable mountain of Department of Energy (DOE) orders, directives, notices, and standards. These DOE dictates seldom take the broad view but focus on highly specialized programs isolated from the overall context of formal operations. The result is a confusing array of specific, and often contradictory, requirements that produce a patchwork of overlapping niche programs. This unnecessary duplication wastes precious resources, dramatically increases the complexity of our work processes, and communicates a sense of confusion to our customers and regulators. Coupled with the artificial divisions that have historically existed among the Laboratory`s formal operations organizations (quality assurance, configuration management, records management, training, etc.), this approach has produced layers of increasingly vague and complex formal operations plans, each of which interprets its parent and adds additional requirements of its own. Organizational gridlock ensues whenever an activity attempts to implement these bureaucratic monstrosities. The integrated formal operations plan presented is to establish a set of requirements that must be met by an integrated formal operations program, assign responsibilities for implementation and operation of the program, and specify criteria against which the performance of the program will be measured. The accountable line manager specifies the items, processes, and information (the controlled elements) to which the formal operations program specified applies. The formal operations program is implemented using a graded approach based on the level of importance of the various controlled elements and the scope of the activities in which they are involved.

Beyond the networks

DEFF Research Database (Denmark)

Andreasen, Manja Hoppe; Møller-Jensen, Lasse

2016-01-01

This paper offers insights from comprehensive case studies of rapidly growing peripheral settlements of Dar es Salaam. The paper explores how a broad range of services and infrastructures have developed and improved over time, and how residents have been engaged in this in various ways. The gradual...... improvements in services and infrastructure are to some extent created, organized and financed by residents through informal self-help solutions, which are often costly and place huge strains on residents' time and resources. Alongside this, residents are also involved in attracting formal service providers...... through applications, co-financing of network extensions as well as lobbying efforts towards urban authorities and service providers. The formal service providers primarily take a reactive role, responding to demand, requests and political pressure from residents. Post-settlement network extensions...

Switching performance of OBS network model under prefetched real traffic

Science.gov (United States)

Huang, Zhenhua; Xu, Du; Lei, Wen

2005-11-01

Optical Burst Switching (OBS) [1] is now widely considered as an efficient switching technique in building the next generation optical Internet .So it's very important to precisely evaluate the performance of the OBS network model. The performance of the OBS network model is variable in different condition, but the most important thing is that how it works under real traffic load. In the traditional simulation models, uniform traffics are usually generated by simulation software to imitate the data source of the edge node in the OBS network model, and through which the performance of the OBS network is evaluated. Unfortunately, without being simulated by real traffic, the traditional simulation models have several problems and their results are doubtable. To deal with this problem, we present a new simulation model for analysis and performance evaluation of the OBS network, which uses prefetched IP traffic to be data source of the OBS network model. The prefetched IP traffic can be considered as real IP source of the OBS edge node and the OBS network model has the same clock rate with a real OBS system. So it's easy to conclude that this model is closer to the real OBS system than the traditional ones. The simulation results also indicate that this model is more accurate to evaluate the performance of the OBS network system and the results of this model are closer to the actual situation.

Evolution of cooperation under social pressure in multiplex networks.

Science.gov (United States)

Pereda, María

2016-09-01

In this work, we aim to contribute to the understanding of human prosocial behavior by studying the influence that a particular form of social pressure, "being watched," has on the evolution of cooperative behavior. We study how cooperation emerges in multiplex complex topologies by analyzing a particular bidirectionally coupled dynamics on top of a two-layer multiplex network (duplex). The coupled dynamics appears between the prisoner's dilemma game in a network and a threshold cascade model in the other. The threshold model is intended to abstract the behavior of a network of vigilant nodes that impose the pressure of being observed altering hence the temptation to defect of the dilemma. Cooperation or defection in the game also affects the state of a node of being vigilant. We analyze these processes on different duplex networks structures and assess the influence of the topology, average degree and correlated multiplexity, on the outcome of cooperation. Interestingly, we find that the social pressure of vigilance may impact cooperation positively or negatively, depending on the duplex structure, specifically the degree correlations between layers is determinant. Our results give further quantitative insights in the promotion of cooperation under social pressure.

[Mechanisms of articulation between the informal and the formal urban sectors].

Science.gov (United States)

Lomnitz, L

1978-01-01

This article utilizes field data from Mexico City squatter settlements and personal interviews with employers to analyze some aspects of social relations between the informal sector and the formal urban sector, and compares the results with findings of other anthropologists in Mexico and elsewhere to derive a series of theoretical generalizations concerning mechanisms of articulation between the marginal sector and the formal economic and political institutions of the society. The formal sector is postulated to consist of the 3 subsectors of power, capital, and labor, which are in permanent conflict among themselves but all of which enjoy labor security and an assured minimal level of income. The marginal or informal sector lacks employment security, a minimal income level, and bargaining power. It is characterized by a small scale economy utilizing intensive familial labor. The informal sector is marginal to the dominant industrial system of production and the state apparatus, although it fulfills functions in terms of the national economy. 2 types of relationships may be distinguished in the social organization of the marginal sector: reciprocal relations between equals which form a network for the exchange of goods and services, or patron/client relations which are used, for example, in the case of petty entrepreneurs utilizing their relatives and acquaintances to create units of production. The functions of reciprocal relations are affected by social, physical, economic, and psychosocial distance or proximity and may result in exchanges of information, labor assistance, loans, services, or moral support. Patron/client relations may be direct, or the "patron" may be an intermediary. Some reciprocal networks display a pattern of incipient asymmetry leading to formation of true patron/client ties and some petty entrepreneurs or intermediaries manage to develop true patron/client networks; case histories are used to illustrate both phenomena. Intermediaries

Probabilistic reasoning in intelligent systems networks of plausible inference

CERN Document Server

Pearl, Judea

1988-01-01

Probabilistic Reasoning in Intelligent Systems is a complete and accessible account of the theoretical foundations and computational methods that underlie plausible reasoning under uncertainty. The author provides a coherent explication of probability as a language for reasoning with partial belief and offers a unifying perspective on other AI approaches to uncertainty, such as the Dempster-Shafer formalism, truth maintenance systems, and nonmonotonic logic. The author distinguishes syntactic and semantic approaches to uncertainty--and offers techniques, based on belief networks, that provid

Using Alloy to Formally Model and Reason About an OpenFlow Network Switch

OpenAIRE

Mirzaei, Saber; Bahargam, Sanaz; Skowyra, Richard; Kfoury, Assaf; Bestavros, Azer

2016-01-01

Openflow provides a standard interface for separating a network into a data plane and a programmatic control plane. This enables easy network reconfiguration, but introduces the potential for programming bugs to cause network effects. To study OpenFlow switch behavior, we used Alloy to create a software abstraction describing the internal state of a network and its OpenFlow switches. This work is an attempt to model the static and dynamic behaviour a network built using OpenFlow switches.

Competing Structure, Competing Views: The Role of Formal and Informal Social Structures in Shaping Stakeholder Perceptions

Directory of Open Access Journals (Sweden)

Christina Prell

2010-12-01

Full Text Available What is social structure, and how does it influence the views and behaviors of land managers? In this paper, we unpack the term "social structure" in the context of current research on institutions, social networks, and their role(s in resource management. We identify two different kinds of structure, formal and informal, and explore how these link to views of land management and management practice. Formal structures refer to intentionally designed organizations that arise out of larger institutional arrangements; informal ones refer to social networks, based on the communication contacts individuals possess. Our findings show significant correlations between respondents' views regarding land management and their social networks; it is these informal structures that have greater influence on what stakeholders perceive. These findings suggest that stakeholders are less influenced by their particular organizational affiliation or category (e.g., "conservationist" versus "farmer", and more by whom they speak with on a regular basis regarding land management. We conclude with a discussion on the practical implications for resource managers wishing to "design" participatory management, arguing that, if "diversity" is the goal in designing such participatory processes, then diversity needs to translate beyond stakeholder categories to include consideration for the personal, social networks surrounding stakeholders.

Formal education in outdoor studies: introduction

OpenAIRE

Prince, Heather

2015-01-01

Regional cultural perspectives involve outdoor studies in different ways in formal curricula. This section focuses on Western Europe, particularly the UK and Scandinavia, although also has a more international reach in Backman’s consideration of the training of teachers and in place-responsive teaching as described by Mannion and Lynch. ‘Outdoor studies’ is not seen in curricula per se but under various more specialised aspects such as outdoor play, outdoor learning, environmental education, ...

Integrating semi-formal and formal requirements

NARCIS (Netherlands)

Wieringa, Roelf J.; Olivé, Antoni; Dubois, Eric; Pastor, Joan Antoni; Huyts, Sander

1997-01-01

In this paper, we report on the integration of informal, semiformal and formal requirements specification techniques. We present a framework for requirements specification called TRADE, within which several well-known semiformal specification techniques are placed. TRADE is based on an analysis of

Networked Professional Learning: Relating the Formal and the Informal

Science.gov (United States)

Vaessen, Matthieu; van den Beemt, Antoine; de Laat, Maarten

2014-01-01

The increasing complexity of the workplace environment requires teachers and professionals in general to tap into their social networks, inside and outside circles of direct colleagues and collaborators, for finding appropriate knowledge and expertise. This collective process of sharing and constructing knowledge can be considered "networked…

Formal System Verification - Extension 2

Science.gov (United States)

2012-08-08

vision of truly trustworthy systems has been to provide a formally verified microkernel basis. We have previously developed the seL4 microkernel...together with a formal proof (in the theorem prover Isabelle/HOL) of its functional correctness [6]. This means that all the behaviours of the seL4 C...source code are included in the high-level, formal specification of the kernel. This work enabled us to provide further formal guarantees about seL4 , in

Topical Roots of Formal Dialectic

NARCIS (Netherlands)

Krabbe, Erik C. W.

Formal dialectic has its roots in ancient dialectic. We can trace this influence in Charles Hamblin's book on fallacies, in which he introduced his first formal dialectical systems. Earlier, Paul Lorenzen proposed systems of dialogical logic, which were in fact formal dialectical systems avant la

NETWORK, HOW? Perceptions of business people on networking practices

Directory of Open Access Journals (Sweden)

Saskia De Klerk

2010-12-01

Full Text Available Purpose: The purpose of this paper was to contribute to literature on networking from a South African perspective. Literature on networking is mainly concentrated on the European and American contexts with homogeneous groups and traditional divisions. The business landscape of South Africa thus requires more investigation. Problem investigated: Literature regarding networking in an South African context with its dynamic business environment is limited. This article addresses the concerns of how South African business owners and managers perceive networking in their businesses and specifically focus on the South African perspective. Therefore, the focus is on the perceptions of business owners and managers on current networking practices in South Africa. Methodology: A qualitative research design to uncover the rich underlying feelings of business owners and managers was used. The qualitative enquiry consisted of five focus group discussions (n=41 participants among prominent business owners and managers in the Gauteng Province, South Africa. The Gauteng Province was selected since it is the economic and innovation hub of South Africa. Findings and implications: The main findings showed the following main themes of networking that emerged from the data, and included (1 networking as a skill versus a natural ability; (2 the motivation behind networking; (3 the loci of networking; (4 the type of relationships that determine the character of the network; and (5 the relationship characteristics of successful networking. The main contribution of this is that there seems to be different networking situations and applications for different circumstances. According to the participants, it seems that networking in the South African landscape appears to be either relationship or business based. Originality and value of the research: The value of these findings lies in the fact that they contribute to networking literature from a South African perspective

Holographic spin networks from tensor network states

Science.gov (United States)

Singh, Sukhwinder; McMahon, Nathan A.; Brennen, Gavin K.

2018-01-01

In the holographic correspondence of quantum gravity, a global on-site symmetry at the boundary generally translates to a local gauge symmetry in the bulk. We describe one way how the global boundary on-site symmetries can be gauged within the formalism of the multiscale renormalization ansatz (MERA), in light of the ongoing discussion between tensor networks and holography. We describe how to "lift" the MERA representation of the ground state of a generic one dimensional (1D) local Hamiltonian, which has a global on-site symmetry, to a dual quantum state of a 2D "bulk" lattice on which the symmetry appears gauged. The 2D bulk state decomposes in terms of spin network states, which label a basis in the gauge-invariant sector of the bulk lattice. This decomposition is instrumental to obtain expectation values of gauge-invariant observables in the bulk, and also reveals that the bulk state is generally entangled between the gauge and the remaining ("gravitational") bulk degrees of freedom that are not fixed by the symmetry. We present numerical results for ground states of several 1D critical spin chains to illustrate that the bulk entanglement potentially depends on the central charge of the underlying conformal field theory. We also discuss the possibility of emergent topological order in the bulk using a simple example, and also of emergent symmetries in the nongauge (gravitational) sector in the bulk. More broadly, our holographic model translates the MERA, a tensor network state, to a superposition of spin network states, as they appear in lattice gauge theories in one higher dimension.

computer networks

Directory of Open Access Journals (Sweden)

N. U. Ahmed

2002-01-01

Full Text Available In this paper, we construct a new dynamic model for the Token Bucket (TB algorithm used in computer networks and use systems approach for its analysis. This model is then augmented by adding a dynamic model for a multiplexor at an access node where the TB exercises a policing function. In the model, traffic policing, multiplexing and network utilization are formally defined. Based on the model, we study such issues as (quality of service QoS, traffic sizing and network dimensioning. Also we propose an algorithm using feedback control to improve QoS and network utilization. Applying MPEG video traces as the input traffic to the model, we verify the usefulness and effectiveness of our model.

Uranium mining and metallurgy library information service under the network environment

International Nuclear Information System (INIS)

Tang Lilei

2012-01-01

This paper analyzes the effect of the network environment on the uranium mining and metallurgy of the information service. Introduces some measures such as strengthening professional characteristic literature resources construction, changing the service mode, building up information navigation, deepening service, meet the individual needs of users, raising librarian's quality, promoting the co-construction and sharing of library information resources, and puts forward the development idea of uranium mining and metallurgy library information service under the network environment. (author)

Lending Policies of Informal, Formal, and Semi-formal Lenders: Evidence from Vietnam

NARCIS (Netherlands)

Lensink, B.W.; Pham, T.T.T.

2007-01-01

This paper compares lending policies of formal, informal and semiformal lenders with respect to household lending in Vietnam. The analysis suggests that the probability of using formal or semiformal credit increases if borrowers provide collateral, a guarantor and/or borrow for business-related

Security Evaluation of the Cyber Networks under Advanced Persistent Threats

NARCIS (Netherlands)

Yang, L.; Li, Pengdeng; Yang, Xiaofan; Tang, Yuan Yan

2017-01-01

Advanced persistent threats (APTs) pose a grave threat to cyberspace, because they deactivate all the conventional cyber defense mechanisms. This paper addresses the issue of evaluating the security of the cyber networks under APTs. For this purpose, a dynamic model capturing the APT-based

Influence of municipal policy and individual characteristics on the use of informal and formal domestic help in the Netherlands.

Science.gov (United States)

Marangos, Anna Maria; Waverijn, Geeke; de Klerk, Mirjam; Iedema, Jurjen; Groenewegen, Peter P

2018-05-24

The responsibility for care and social support in the Netherlands has been decentralized to the municipalities, on the assumption that they are able to organise care and social support more effectively and efficiently. Municipalities are responsible for offering citizens the social support they need. They have policy discretion to decide how and to what extent they encourage and support the use of informal help. This article explored whether the local policy focus on informal or formal help influences the actual take-up of domestic help. Data on 567 physically disabled people who use informal or formal help in the household were linked to local policy data in 167 municipalities. We performed multilevel multinomial regression analyses. Since we expected that local policy will have more influence on people with slight or moderate disabilities, cohabitees and people aged under 75, cross-level interaction terms were included between characteristics of local policy and of individuals. The findings reveal differences between municipalities in their policy on support and differences in the use of formal or informal support between municipalities. We found no relationship between local emphasis on informal help and the use of informal help. Possible explanations: some people have a small social network, people using informal help did not apply for municipality support or even do not know the possibility exists. Copyright © 2018 Elsevier B.V. All rights reserved.

Signaling mechanisms underlying the robustness and tunability of the plant immune network

Science.gov (United States)

Kim, Yungil; Tsuda, Kenichi; Igarashi, Daisuke; Hillmer, Rachel A.; Sakakibara, Hitoshi; Myers, Chad L.; Katagiri, Fumiaki

2014-01-01

Summary How does robust and tunable behavior emerge in a complex biological network? We sought to understand this for the signaling network controlling pattern-triggered immunity (PTI) in Arabidopsis. A dynamic network model containing four major signaling sectors, the jasmonate, ethylene, PAD4, and salicylate sectors, which together explain up to 80% of the PTI level, was built using data for dynamic sector activities and PTI levels under exhaustive combinatorial sector perturbations. Our regularized multiple regression model had a high level of predictive power and captured known and unexpected signal flows in the network. The sole inhibitory sector in the model, the ethylene sector, was central to the network robustness via its inhibition of the jasmonate sector. The model's multiple input sites linked specific signal input patterns varying in strength and timing to different network response patterns, indicating a mechanism enabling tunability. PMID:24439900

DAILY RAINFALL-RUNOFF MODELLING BY NEURAL NETWORKS ...

African Journals Online (AJOL)

K. Benzineb, M. Remaoun

2016-09-01

Sep 1, 2016 ... The hydrologic behaviour modelling of w. Journal of ... i Ouahrane's basin from rainfall-runoff relation which is non-linea networks ... will allow checking efficiency of formal neural networks for flows simulation in semi-arid zone.

Concepciones acerca de la maternidad en la educación formal y no formal

Directory of Open Access Journals (Sweden)

Alvarado Calderón, Kathia

2005-06-01

Full Text Available Este artículo presenta algunos resultados de la investigación desarrollada en el Instituto de Investigación en Educación (INIE, bajo el nombre "Construcción del concepto de maternidad en la educación formal y no formal". Utilizando un enfoque cualitativo de investigación, recurrimos a las técnicas de elaboración de dibujos, entrevistas y grupo focal como recursos para la recolección de la información. De esta manera, podemos acercarnos a las concepciones de la maternidad que utilizan los participantes de las diferentes instancias educativas (formal y no formal con quienes se trabajó. This article presents some results the research developed in the Instituto de Investigación en Educación (INIE, named "Construcción del concepto de maternidad en la educación formal y no formal". It begins with a theoretical analysis about social conceptions regarding motherhood in the occidental societies. Among the techniques for gathering information were thematic drawing, interview and focus group, using a qualitative approach research method. This is followed by a brief summary of main findings. The article concludes with a proposal of future working lines for the deconstruction of the motherhood concept in formal and informal education contexts.

Regular Topologies for Gigabit Wide-Area Networks. Volume 1

Science.gov (United States)

Shacham, Nachum; Denny, Barbara A.; Lee, Diane S.; Khan, Irfan H.; Lee, Danny Y. C.; McKenney, Paul

1994-01-01

In general terms, this project aimed at the analysis and design of techniques for very high-speed networking. The formal objectives of the project were to: (1) Identify switch and network technologies for wide-area networks that interconnect a large number of users and can provide individual data paths at gigabit/s rates; (2) Quantitatively evaluate and compare existing and proposed architectures and protocols, identify their strength and growth potentials, and ascertain the compatibility of competing technologies; and (3) Propose new approaches to existing architectures and protocols, and identify opportunities for research to overcome deficiencies and enhance performance. The project was organized into two parts: 1. The design, analysis, and specification of techniques and protocols for very-high-speed network environments. In this part, SRI has focused on several key high-speed networking areas, including Forward Error Control (FEC) for high-speed networks in which data distortion is the result of packet loss, and the distribution of broadband, real-time traffic in multiple user sessions. 2. Congestion Avoidance Testbed Experiment (CATE). This part of the project was done within the framework of the DARTnet experimental T1 national network. The aim of the work was to advance the state of the art in benchmarking DARTnet's performance and traffic control by developing support tools for network experimentation, by designing benchmarks that allow various algorithms to be meaningfully compared, and by investigating new queueing techniques that better satisfy the needs of best-effort and reserved-resource traffic. This document is the final technical report describing the results obtained by SRI under this project. The report consists of three volumes: Volume 1 contains a technical description of the network techniques developed by SRI in the areas of FEC and multicast of real-time traffic. Volume 2 describes the work performed under CATE. Volume 3 contains the source

Stochastic Online Learning in Dynamic Networks under Unknown Models

Science.gov (United States)

2016-08-02

The key is to develop online learning strategies at each individual node. Specifically, through local information exchange with its neighbors, each...infinitely repeated game with incomplete information and developed a dynamic pricing strategy referred to as Competitive and Cooperative Demand Learning...Stochastic Online Learning in Dynamic Networks under Unknown Models This research aims to develop fundamental theories and practical algorithms for

The Transition from Alliance Networks to Multilateral Alliances in the Global Airline Industry

Directory of Open Access Journals (Sweden)

Sergio G. Lazzarini

2008-01-01

Full Text Available This study examines conditions in which alliance networks (informal webs of bilateral entanglements between firms may or may not evolve into multilateral alliances (broad, formal multiple-firm arrangements. I offer a theory to explain the formation of multilateral alliances based on both the resource profile and the structure of existing interfirm networks, and provide an initial test of that theory in the context of the global airline industry. Using data from 75 global airlines and their alliances, I propose a methodology to retrieve samples of alliance networks and then use regression analysis to assess how the resource profile and the structure of these networks influence their formalization into multilateral alliances. I find that multilateral alliances are more likely to emerge when alliance networks exhibit high resource diversity and network structure characterized by moderate density and high centralization. Apparently, while highly sparse networks reduce actors’ awareness of their potential joint collaboration, highly dense or embedded networks substitute for the need for formal controls accompanying multilateral agreements. The effect of centralization suggests that the formation of multilateral alliances tends to be triggered by leading actors directly connected to other network members.

Why formal learning theory matters for cognitive science.

Science.gov (United States)

Fulop, Sean; Chater, Nick

2013-01-01

This article reviews a number of different areas in the foundations of formal learning theory. After outlining the general framework for formal models of learning, the Bayesian approach to learning is summarized. This leads to a discussion of Solomonoff's Universal Prior Distribution for Bayesian learning. Gold's model of identification in the limit is also outlined. We next discuss a number of aspects of learning theory raised in contributed papers, related to both computational and representational complexity. The article concludes with a description of how semi-supervised learning can be applied to the study of cognitive learning models. Throughout this overview, the specific points raised by our contributing authors are connected to the models and methods under review. Copyright © 2013 Cognitive Science Society, Inc.

Analysis and Reduction of Complex Networks Under Uncertainty

Energy Technology Data Exchange (ETDEWEB)

Knio, Omar M

2014-04-09

This is a collaborative proposal that aims at developing new methods for the analysis and reduction of complex multiscale networks under uncertainty. The approach is based on combining methods of computational singular perturbation (CSP) and probabilistic uncertainty quantification. In deterministic settings, CSP yields asymptotic approximations of reduced-dimensionality “slow manifolds” on which a multiscale dynamical system evolves. Introducing uncertainty raises fundamentally new issues, particularly concerning its impact on the topology of slow manifolds, and means to represent and quantify associated variability. To address these challenges, this project uses polynomial chaos (PC) methods to reformulate uncertain network models, and to analyze them using CSP in probabilistic terms. Specific objectives include (1) developing effective algorithms that can be used to illuminate fundamental and unexplored connections among model reduction, multiscale behavior, and uncertainty, and (2) demonstrating the performance of these algorithms through applications to model problems.

Generalised BRST symmetry and gaugeon formalism for perturbative quantum gravity: Novel observation

International Nuclear Information System (INIS)

Upadhyay, Sudhaker

2014-01-01

In this paper the novel features of Yokoyama gaugeon formalism are stressed out for the theory of perturbative quantum gravity in the Einstein curved spacetime. The quantum gauge transformations for the theory of perturbative gravity are demonstrated in the framework of gaugeon formalism. These quantum gauge transformations lead to renormalised gauge parameter. Further, we analyse the BRST symmetric gaugeon formalism which embeds more acceptable Kugo–Ojima subsidiary condition. Further, the BRST symmetry is made finite and field-dependent. Remarkably, the Jacobian of path integral under finite and field-dependent BRST symmetry amounts to the exact gaugeon action in the effective theory of perturbative quantum gravity. -- Highlights: •We analyse the perturbative gravity in gaugeon formalism. •The generalisation of BRST transformation is also studied in this context. •Within the generalised BRST framework we found the exact gaugeon modes in the theory

Managerial strategies and behavior in networks

NARCIS (Netherlands)

O'Toole, Laurence J.; Meier, Kenneth J.

2001-01-01

This manuscript provides the first systematic test of a formal theory of managing government programs in a network context (see O’Toole and Meier 1999). Using data from several hundred school districts in Texas, we create a measure of network management that reflects the time school superintendents

Functional brain networks underlying detection and integration of disconfirmatory evidence.

Science.gov (United States)

Lavigne, Katie M; Metzak, Paul D; Woodward, Todd S

2015-05-15

.g., 17s after trial onset) the hemodynamic responses associated with all three networks were simultaneously active. These findings highlight distinct cognitive processes and corresponding functional brain networks underlying stages of disconfirmatory evidence integration, and demonstrate the power of multivariate and multi-experiment methodology in cognitive neuroscience. Copyright © 2015 Elsevier Inc. All rights reserved.

Preferences for and Barriers to Formal and Informal Athletic Training Continuing Education Activities

Science.gov (United States)

Armstrong, Kirk J.; Weidner, Thomas G.

2011-01-01

Context: Our previous research determined the frequency of participation and perceived effect of formal and informal continuing education (CE) activities. However, actual preferences for and barriers to CE must be characterized. Objective: To determine the types of formal and informal CE activities preferred by athletic trainers (ATs) and barriers to their participation in these activities. Design: Cross-sectional study. Setting: Athletic training practice settings. Patients or Other Participants: Of a geographically stratified random sample of 1000 ATs, 427 ATs (42.7%) completed the survey. Main Outcome Measure(s): As part of a larger study, the Survey of Formal and Informal Athletic Training Continuing Education Activities (FIATCEA) was developed and administered electronically. The FIATCEA consists of demographic characteristics and Likert scale items (1 = strongly disagree, 5 = strongly agree) about preferred CE activities and barriers to these activities. Internal consistency of survey items, as determined by Cronbach α, was 0.638 for preferred CE activities and 0.860 for barriers to these activities. Descriptive statistics were computed for all items. Differences between respondent demographic characteristics and preferred CE activities and barriers to these activities were determined via analysis of variance and dependent t tests. The α level was set at .05. Results: Hands-on clinical workshops and professional networking were the preferred formal and informal CE activities, respectively. The most frequently reported barriers to formal CE were the cost of attending and travel distance, whereas the most frequently reported barriers to informal CE were personal and job-specific factors. Differences were noted between both the cost of CE and travel distance to CE and all other barriers to CE participation (F1,411 = 233.54, P formal CE activities. The same barriers (eg, cost, travel distance) to formal CE appeared to be universal to all ATs. Informal CE was

Feasibility of Optical Packet Switched WDM Networks without Packet Synchronisation Under Bursty Traffic Conditions

DEFF Research Database (Denmark)

Fjelde, Tina; Hansen, Peter Bukhave; Kloch, Allan

1999-01-01

We show that complex packet synchronisation may be avoided in optical packetswitched networks. Detailed traffic analysis demonstrates that packet lossratios of 1e-10 are feasible under bursty traffic conditions for a highcapacity network consisting of asynchronously operated add-drop switch...

Common and distinct brain networks underlying verbal and visual creativity.

Science.gov (United States)

Zhu, Wenfeng; Chen, Qunlin; Xia, Lingxiang; Beaty, Roger E; Yang, Wenjing; Tian, Fang; Sun, Jiangzhou; Cao, Guikang; Zhang, Qinglin; Chen, Xu; Qiu, Jiang

2017-04-01

Creativity is imperative to the progression of human civilization, prosperity, and well-being. Past creative researches tends to emphasize the default mode network (DMN) or the frontoparietal network (FPN) somewhat exclusively. However, little is known about how these networks interact to contribute to creativity and whether common or distinct brain networks are responsible for visual and verbal creativity. Here, we use functional connectivity analysis of resting-state functional magnetic resonance imaging data to investigate visual and verbal creativity-related regions and networks in 282 healthy subjects. We found that functional connectivity within the bilateral superior parietal cortex of the FPN was negatively associated with visual and verbal creativity. The strength of connectivity between the DMN and FPN was positively related to both creative domains. Visual creativity was negatively correlated with functional connectivity within the precuneus of the pDMN and right middle frontal gyrus of the FPN, and verbal creativity was negatively correlated with functional connectivity within the medial prefrontal cortex of the aDMN. Critically, the FPN mediated the relationship between the aDMN and verbal creativity, and it also mediated the relationship between the pDMN and visual creativity. Taken together, decreased within-network connectivity of the FPN and DMN may allow for flexible between-network coupling in the highly creative brain. These findings provide indirect evidence for the cooperative role of the default and executive control networks in creativity, extending past research by revealing common and distinct brain systems underlying verbal and visual creative cognition. Hum Brain Mapp 38:2094-2111, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

The base of the iceberg: informal learning and its impact on formal and non-formal learning

OpenAIRE

Rogers, Alan

2014-01-01

The author looks at learning (formal, non-formal and informal) and examines the hidden world of informal (unconscious, unplanned) learning. He points out the importance of informal learning for creating tacit attitudes and values, knowledge and skills which influence (conscious, planned) learning - formal and non-formal. Moreover, he explores the implications of informal learning for educational planners and teachers in the context of lifelong learning. While mainly aimed at adult educators, ...

Strengthening think tank networks | IDRC - International ...

International Development Research Centre (IDRC) Digital Library (Canada)

Several new collaborative networks have emerged as a result. The degree of formality and type of institutional membership of these networks has varied, as have the drivers behind their creation. What is common between them is the ... Foro Social de Deuda Externa y Desarrollo de Honduras. Institution Country. Honduras.

General formalism for the stability of thin-shell wormholes in 2 + 1 dimensions

Energy Technology Data Exchange (ETDEWEB)

Bejarano, Cecilia [Instituto de Astronomia y Fisica del Espacio, Buenos Aires (Argentina); Eiroa, Ernesto F. [Instituto de Astronomia y Fisica del Espacio, Buenos Aires (Argentina); Universidad de Buenos Aires, Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Buenos Aires (Argentina); Simeone, Claudio [Universidad de Buenos Aires, Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Buenos Aires (Argentina); IFIBA-CONICET, Buenos Aires (Argentina)

2014-08-15

In this article we theoretically construct circular thin-shell wormholes in a 2 + 1-dimensional spacetime. The construction is symmetric with respect to the throat. We present a general formalism for the study of the mechanical stability under perturbations preserving the circular symmetry of the configurations, adopting a linearized equation of state for the exotic matter at the throat. We apply the formalism to several examples. (orig.)

General formalism for the stability of thin-shell wormholes in 2 + 1 dimensions

International Nuclear Information System (INIS)

Bejarano, Cecilia; Eiroa, Ernesto F.; Simeone, Claudio

2014-01-01

In this article we theoretically construct circular thin-shell wormholes in a 2 + 1-dimensional spacetime. The construction is symmetric with respect to the throat. We present a general formalism for the study of the mechanical stability under perturbations preserving the circular symmetry of the configurations, adopting a linearized equation of state for the exotic matter at the throat. We apply the formalism to several examples. (orig.)

Teacher Directed Design: Content Knowledge, Pedagogy and Assessment under the Nevada K-12 Real-Time Seismic Network

Science.gov (United States)

Cantrell, P.; Ewing-Taylor, J.; Crippen, K. J.; Smith, K. D.; Snelson, C. M.

2004-12-01

Education professionals and seismologists under the emerging SUN (Shaking Up Nevada) program are leveraging the existing infrastructure of the real-time Nevada K-12 Seismic Network to provide a unique inquiry based science experience for teachers. The concept and effort are driven by teacher needs and emphasize rigorous content knowledge acquisition coupled with the translation of that knowledge into an integrated seismology based earth sciences curriculum development process. We are developing a pedagogical framework, graduate level coursework, and materials to initiate the SUN model for teacher professional development in an effort to integrate the research benefits of real-time seismic data with science education needs in Nevada. A component of SUN is to evaluate teacher acquisition of qualified seismological and earth science information and pedagogy both in workshops and in the classroom and to assess the impact on student achievement. SUN's mission is to positively impact earth science education practices. With the upcoming EarthScope initiative, the program is timely and will incorporate EarthScope real-time seismic data (USArray) and educational materials in graduate course materials and teacher development programs. A number of schools in Nevada are contributing real-time data from both inexpensive and high-quality seismographs that are integrated with Nevada regional seismic network operations as well as the IRIS DMC. A powerful and unique component of the Nevada technology model is that schools can receive "stable" continuous live data feeds from 100's seismograph stations in Nevada, California and world (including live data from Earthworm systems and the IRIS DMC BUD - Buffer of Uniform Data). Students and teachers see their own networked seismograph station within a global context, as participants in regional and global monitoring. The robust real-time Internet communications protocols invoked in the Nevada network provide for local data acquisition

Memory function formalism applied to electronic transport in disordered systems

International Nuclear Information System (INIS)

Cunha Lima, I.C. da

1984-01-01

Memory function formalism is briefly reviewed and applied to electronic transport using the projection operator technique. The resistivity of a disordered 2-D electron gas under strong magnetic field is obtained in terms of force-force correlation function. (Author) [pt

Representations of spacetime: Formalism and ontological commitment

Science.gov (United States)

Bain, Jonathan Stanley

This dissertation consists of two parts. The first is on the relation between formalism and ontological commitment in the context of theories of spacetime, and the second is on scientific realism. The first part begins with a look at how the substantivalist/relationist debate over the ontological status of spacetime has been influenced by a particular mathematical formalism, that of tensor analysis on differential manifolds (TADM). This formalism has motivated the substantivalist position known as manifold substantivalism. Chapter 1 focuses on the hole argument which maintains that manifold substantivalism is incompatible with determinism. I claim that the realist motivations underlying manifold substantivalism can be upheld, and the hole argument avoided, by adopting structural realism with respect to spacetime. In this context, this is the claim that it is the structure that spacetime points enter into that warrants belief and not the points themselves. In Chapter 2, an elimination principle is defined by means of which a distinction can be made between surplus structure and essential structure with respect to formulations of a theory in two distinct mathematical formulations and some prior ontological commitments. This principle is then used to demonstrate that manifold points may be considered surplus structure in the formulation of field theories. This suggests that, if we are disposed to read field theories literally, then, at most, it should be the essential structure common to all alternative formulations of such theories that should be taken literally. I also investigate how the adoption of alternative formalisms informs other issues in the philosophy of spacetime. Chapter 3 offers a realist position which takes a semantic moral from the preceding investigation and an epistemic moral from work done on reliability. The semantic moral advises us to read only the essential structure of our theories literally. The epistemic moral shows us that such structure

Mechanized extraction of topology anti-patterns in wireless networks

NARCIS (Netherlands)

Woehrle, M.; Bakhshi, R.; Mousavi, M.R.; Derrick, J.; Gnesi, S.; Latella, D.; Treharne, H.

2012-01-01

Exhaustive and mechanized formal verification of wireless networks is hampered by the huge number of possible topologies and the large size of the actual networks. However, the generic communication structure in such networks allows for reducing the root causes of faults to faulty (sub-)topologies,

Periodic dynamics in queuing networks

Energy Technology Data Exchange (ETDEWEB)

Addabbo, Tommaso [Information Engineering Department, University of Siena, Via Roma 56, 53100 Siena (Italy)], E-mail: addabbo@dii.unisi.it; Kocarev, Ljupco [Macedonian Academy of Sciences and Arts, bul. Krste Misirkov 2, P.O. Box 428, 1000 Skopje, Republic of Macedonia (Macedonia, The Former Yugoslav Republic of)], E-mail: lkocarev@ucsd.edu

2009-08-30

This paper deals with state-dependent open Markovian (or exponential) queuing networks, for which arrival and service rates, as well as routing probabilities, may depend on the queue lengths. For a network of this kind, following Mandelbaum and Pats, we provide a formal definition of its associated fluid model, and we focus on the relationships which may occur between the network stochastic dynamics and the deterministic dynamics of its corresponding fluid model, particularly focusing on queuing networks whose fluid models have global periodic attractors.

A method for under-sampled ecological network data analysis: plant-pollination as case study

Directory of Open Access Journals (Sweden)

Peter B. Sorensen

2012-01-01

Full Text Available In this paper, we develop a method, termed the Interaction Distribution (ID method, for analysis of quantitative ecological network data. In many cases, quantitative network data sets are under-sampled, i.e. many interactions are poorly sampled or remain unobserved. Hence, the output of statistical analyses may fail to differentiate between patterns that are statistical artefacts and those which are real characteristics of ecological networks. The ID method can support assessment and inference of under-sampled ecological network data. In the current paper, we illustrate and discuss the ID method based on the properties of plant-animal pollination data sets of flower visitation frequencies. However, the ID method may be applied to other types of ecological networks. The method can supplement existing network analyses based on two definitions of the underlying probabilities for each combination of pollinator and plant species: (1, pi,j: the probability for a visit made by the i’th pollinator species to take place on the j’th plant species; (2, qi,j: the probability for a visit received by the j’th plant species to be made by the i’th pollinator. The method applies the Dirichlet distribution to estimate these two probabilities, based on a given empirical data set. The estimated mean values for pi,j and qi,j reflect the relative differences between recorded numbers of visits for different pollinator and plant species, and the estimated uncertainty of pi,j and qi,j decreases with higher numbers of recorded visits.

MODELS OF AIR TRAFFIC CONTROLLERS ERRORS PREVENTION IN TERMINAL CONTROL AREAS UNDER UNCERTAINTY CONDITIONS

Directory of Open Access Journals (Sweden)

Volodymyr Kharchenko

2017-03-01

Full Text Available Purpose: the aim of this study is to research applied models of air traffic controllers’ errors prevention in terminal control areas (TMA under uncertainty conditions. In this work the theoretical framework descripting safety events and errors of air traffic controllers connected with the operations in TMA is proposed. Methods: optimisation of terminal control area formal description based on the Threat and Error management model and the TMA network model of air traffic flows. Results: the human factors variables associated with safety events in work of air traffic controllers under uncertainty conditions were obtained. The Threat and Error management model application principles to air traffic controller operations and the TMA network model of air traffic flows were proposed. Discussion: Information processing context for preventing air traffic controller errors, examples of threats in work of air traffic controllers, which are relevant for TMA operations under uncertainty conditions.

Reducing Hospital Readmissions Through Preferred Networks Of Skilled Nursing Facilities.

Science.gov (United States)

McHugh, John P; Foster, Andrew; Mor, Vincent; Shield, Renée R; Trivedi, Amal N; Wetle, Terrie; Zinn, Jacqueline S; Tyler, Denise A

2017-09-01

Establishing preferred provider networks of skilled nursing facilities (SNFs) is one approach hospital administrators are using to reduce excess thirty-day readmissions and avoid Medicare penalties or to reduce beneficiaries' costs as part of value-based payment models. However, hospitals are also required to provide patients at discharge with a list of Medicare-eligible providers and cannot explicitly restrict patient choice. This requirement complicates the development of a SNF network. Furthermore, there is little evidence about the effectiveness of network development in reducing readmission rates. We used a concurrent mixed-methods approach, combining Medicare claims data for the period 2009-13 with qualitative data gathered from interviews during site visits to hospitals in eight US markets in March-October 2015, to examine changes in rehospitalization rates and differences in practices between hospitals that did and did not develop formal SNF networks. Four hospitals had developed formal SNF networks as part of their care management efforts. These hospitals saw a relative reduction from 2009 to 2013 in readmission rates for patients discharged to SNFs that was 4.5 percentage points greater than the reduction for hospitals without formal networks. Interviews revealed that those with networks expanded existing relationships with SNFs, effectively managed patient data, and exercised a looser interpretation of patient choice. Project HOPE—The People-to-People Health Foundation, Inc.

Formalized Epistemology, Logic, and Grammar

Science.gov (United States)

Bitbol, Michel

The task of a formal epistemology is defined. It appears that a formal epistemology must be a generalization of "logic" in the sense of Wittgenstein's Tractatus. The generalization is required because, whereas logic presupposes a strict relation between activity and language, this relation may be broken in some domains of experimental enquiry (e.g., in microscopic physics). However, a formal epistemology should also retain a major feature of Wittgenstein's "logic": It must not be a discourse about scientific knowledge, but rather a way of making manifest the structures usually implicit in knowledge-gaining activity. This strategy is applied to the formalism of quantum mechanics.

Learning gene networks under SNP perturbations using eQTL datasets.

Directory of Open Access Journals (Sweden)

Lingxue Zhang

2014-02-01

Full Text Available The standard approach for identifying gene networks is based on experimental perturbations of gene regulatory systems such as gene knock-out experiments, followed by a genome-wide profiling of differential gene expressions. However, this approach is significantly limited in that it is not possible to perturb more than one or two genes simultaneously to discover complex gene interactions or to distinguish between direct and indirect downstream regulations of the differentially-expressed genes. As an alternative, genetical genomics study has been proposed to treat naturally-occurring genetic variants as potential perturbants of gene regulatory system and to recover gene networks via analysis of population gene-expression and genotype data. Despite many advantages of genetical genomics data analysis, the computational challenge that the effects of multifactorial genetic perturbations should be decoded simultaneously from data has prevented a widespread application of genetical genomics analysis. In this article, we propose a statistical framework for learning gene networks that overcomes the limitations of experimental perturbation methods and addresses the challenges of genetical genomics analysis. We introduce a new statistical model, called a sparse conditional Gaussian graphical model, and describe an efficient learning algorithm that simultaneously decodes the perturbations of gene regulatory system by a large number of SNPs to identify a gene network along with expression quantitative trait loci (eQTLs that perturb this network. While our statistical model captures direct genetic perturbations of gene network, by performing inference on the probabilistic graphical model, we obtain detailed characterizations of how the direct SNP perturbation effects propagate through the gene network to perturb other genes indirectly. We demonstrate our statistical method using HapMap-simulated and yeast eQTL datasets. In particular, the yeast gene network

Formal Modeling and Verification of Interlocking Systems Featuring Sequential Release

DEFF Research Database (Denmark)

Vu, Linh Hong; Haxthausen, Anne Elisabeth; Peleska, Jan

2015-01-01

In this paper, we present a method and an associated tool suite for formal verification of the new ETCS level 2 based Danish railway interlocking systems. We have made a generic and reconfigurable model of the system behavior and generic high-level safety properties. This model accommodates seque...... SMT based bounded model checking (BMC) and inductive reasoning, we are able to verify the properties for model instances corresponding to railway networks of industrial size. Experiments also show that BMC is efficient for finding bugs in the railway interlocking designs....

Formal Modeling and Verification of Interlocking Systems Featuring Sequential Release

DEFF Research Database (Denmark)

Vu, Linh Hong; Haxthausen, Anne Elisabeth; Peleska, Jan

2014-01-01

In this paper, we present a method and an associated tool suite for formal verification of the new ETCS level 2 based Danish railway interlocking systems. We have made a generic and reconfigurable model of the system behavior and generic high-level safety properties. This model accommodates seque...... SMT based bounded model checking (BMC) and inductive reasoning, we are able to verify the properties for model instances corresponding to railway networks of industrial size. Experiments also show that BMC is efficient for finding bugs in the railway interlocking designs....

Unification of Information Security Policies for Network Security Solutions

Directory of Open Access Journals (Sweden)

D.S. Chernyavskiy

2012-03-01

Full Text Available Diversity of command languages on network security solutions’ (NSS interfaces causes problems in a process of information security policy (ISP deployment. Unified model for security policy representation and implementation in NSS could aid to avoid such problems and consequently enhance efficiency of the process. The proposed solution is Unified language for network security policy (ULNSP. The language is based on formal languages theory, and being coupled with its translator, ULNSP makes it possible to formalize and implement ISP independently of particular NSS.

A multi-period distribution network design model under demand uncertainty

Science.gov (United States)

Tabrizi, Babak H.; Razmi, Jafar

2013-05-01

Supply chain management is taken into account as an inseparable component in satisfying customers' requirements. This paper deals with the distribution network design (DND) problem which is a critical issue in achieving supply chain accomplishments. A capable DND can guarantee the success of the entire network performance. However, there are many factors that can cause fluctuations in input data determining market treatment, with respect to short-term planning, on the one hand. On the other hand, network performance may be threatened by the changes that take place within practicing periods, with respect to long-term planning. Thus, in order to bring both kinds of changes under control, we considered a new multi-period, multi-commodity, multi-source DND problem in circumstances where the network encounters uncertain demands. The fuzzy logic is applied here as an efficient tool for controlling the potential customers' demand risk. The defuzzifying framework leads the practitioners and decision-makers to interact with the solution procedure continuously. The fuzzy model is then validated by a sensitivity analysis test, and a typical problem is solved in order to illustrate the implementation steps. Finally, the formulation is tested by some different-sized problems to show its total performance.

An effective method to improve the robustness of small-world networks under attack

International Nuclear Information System (INIS)

Zhang Zheng-Zhen; Xu Wen-Jun; Lin Jia-Ru; Zeng Shang-You

2014-01-01

In this study, the robustness of small-world networks to three types of attack is investigated. Global efficiency is introduced as the network coefficient to measure the robustness of a small-world network. The simulation results prove that an increase in rewiring probability or average degree can enhance the robustness of the small-world network under all three types of attack. The effectiveness of simultaneously increasing both rewiring probability and average degree is also studied, and the combined increase is found to significantly improve the robustness of the small-world network. Furthermore, the combined effect of rewiring probability and average degree on network robustness is shown to be several times greater than that of rewiring probability or average degree individually. This means that small-world networks with a relatively high rewiring probability and average degree have advantages both in network communications and in good robustness to attacks. Therefore, simultaneously increasing rewiring probability and average degree is an effective method of constructing realistic networks. Consequently, the proposed method is useful to construct efficient and robust networks in a realistic scenario. (interdisciplinary physics and related areas of science and technology)

Indigenous Knowledge and Education from the Quechua Community to School: Beyond the Formal/Non-Formal Dichotomy

Science.gov (United States)

Sumida Huaman, Elizabeth; Valdiviezo, Laura Alicia

2014-01-01

In this article, we propose to approach Indigenous education beyond the formal/non-formal dichotomy. We argue that there is a critical need to conscientiously include Indigenous knowledge in education processes from the school to the community; particularly, when formal systems exclude Indigenous cultures and languages. Based on ethnographic…

Border detection in complex networks

International Nuclear Information System (INIS)

Travencolo, Bruno A N; Viana, Matheus Palhares; Costa, Luciano da Fontoura

2009-01-01

One important issue implied by the finite nature of real-world networks regards the identification of their more external (border) and internal nodes. The present work proposes a formal and objective definition of these properties, founded on the recently introduced concept of node diversity. It is shown that this feature does not exhibit any relevant correlation with several well-established complex networks measurements. A methodology for the identification of the borders of complex networks is described and illustrated with respect to theoretical (geographical and knitted networks) as well as real-world networks (urban and word association networks), yielding interesting results and insights in both cases.

New procedure for departure formalities

CERN Multimedia

HR & GS Departments

2011-01-01

As part of the process of simplifying procedures and rationalising administrative processes, the HR and GS Departments have introduced new personalised departure formalities on EDH. These new formalities have applied to students leaving CERN since last year and from 17 October 2011 this procedure will be extended to the following categories of CERN personnel: Staff members, Fellows and Associates. It is planned to extend this electronic procedure to the users in due course. What purpose do departure formalities serve? The departure formalities are designed to ensure that members of the personnel contact all the relevant services in order to return any necessary items (equipment, cards, keys, dosimeter, electronic equipment, books, etc.) and are aware of all the benefits to which they are entitled on termination of their contract. The new departure formalities on EDH have the advantage of tailoring the list of services that each member of the personnel must visit to suit his individual contractual and p...

Robustness of the Drinking Water Distribution Network under Changing Future Demand

NARCIS (Netherlands)

Agudelo-Vera, C.; Blokker, M.; Vreeburg, J.; Bongard, T.; Hillegers, S.; Van der Hoek, J.P.

2014-01-01

A methodology to determine the robustness of the drinking water distribution system is proposed. The performance of three networks under ten future demand scenarios was tested, using head loss and residence time as indicators. The scenarios consider technological and demographic changes. Daily

Multiplex network analysis of employee performance and employee social relationships

Science.gov (United States)

Cai, Meng; Wang, Wei; Cui, Ying; Stanley, H. Eugene

2018-01-01

In human resource management, employee performance is strongly affected by both formal and informal employee networks. Most previous research on employee performance has focused on monolayer networks that can represent only single categories of employee social relationships. We study employee performance by taking into account the entire multiplex structure of underlying employee social networks. We collect three datasets consisting of five different employee relationship categories in three firms, and predict employee performance using degree centrality and eigenvector centrality in a superimposed multiplex network (SMN) and an unfolded multiplex network (UMN). We use a quadratic assignment procedure (QAP) analysis and a regression analysis to demonstrate that the different categories of relationship are mutually embedded and that the strength of their impact on employee performance differs. We also use weighted/unweighted SMN/UMN to measure the predictive accuracy of this approach and find that employees with high centrality in a weighted UMN are more likely to perform well. Our results shed new light on how social structures affect employee performance.

Framing the Adoption of Serious Games in Formal Education

Science.gov (United States)

Arnab, Sylvester; Berta, Riccardo; Earp, Jeffrey; de Freitas, Sara; Popescu, Maria; Romero, Margarida; Stanescu, Ioana; Usart, Mireia

2012-01-01

Nowadays formal education systems are under increasing pressure to respond and adapt to rapid technological innovation and associated changes in the way we work and live. As well as accommodation of technology in its ever-diversifying forms, there is a fundamental need to enhance learning processes through evolution in pedagogical approaches, so…

Measuring the evolutionary rewiring of biological networks.

Directory of Open Access Journals (Sweden)

Chong Shou

Full Text Available We have accumulated a large amount of biological network data and expect even more to come. Soon, we anticipate being able to compare many different biological networks as we commonly do for molecular sequences. It has long been believed that many of these networks change, or "rewire", at different rates. It is therefore important to develop a framework to quantify the differences between networks in a unified fashion. We developed such a formalism based on analogy to simple models of sequence evolution, and used it to conduct a systematic study of network rewiring on all the currently available biological networks. We found that, similar to sequences, biological networks show a decreased rate of change at large time divergences, because of saturation in potential substitutions. However, different types of biological networks consistently rewire at different rates. Using comparative genomics and proteomics data, we found a consistent ordering of the rewiring rates: transcription regulatory, phosphorylation regulatory, genetic interaction, miRNA regulatory, protein interaction, and metabolic pathway network, from fast to slow. This ordering was found in all comparisons we did of matched networks between organisms. To gain further intuition on network rewiring, we compared our observed rewirings with those obtained from simulation. We also investigated how readily our formalism could be mapped to other network contexts; in particular, we showed how it could be applied to analyze changes in a range of "commonplace" networks such as family trees, co-authorships and linux-kernel function dependencies.

Wills Women: A Source for Analysis of Family Strategies and Networks of Formal and Informal Power of the Castilian Nobility

Directory of Open Access Journals (Sweden)

Yolanda GUERRERO NAVARRETE

2016-12-01

Full Text Available This paper tries to make a first approach to the concept and exercise of power by women of the aristocracy of the late medieval Castile. To do this I will use as a source of wills analysis of noblewomen and I will rely on one of the new paradigms recently coined by historians of women studies: The Queenship. This innovative approach articulates the analysis of female power around the following scheme: the definition of the power of women, both in its more traditional aspect (marriages, alliances, lineage, and the newest (client networks, influences, «partnership»... or facet «informal» of female power. The analysis of the aspects that we might consider as «formal power», the «houses» of the queens and the study of their ability to manage and administer their own property. Finally, the construction of a model of «Queen» and the importance, meaning, symbolism and function that takes the same in the late medieval political game. The goal is to bring this model to the Castilian aristocracy through said tripartite scheme.

Governance and strategy of entrepreneurial networks: an introduction

NARCIS (Netherlands)

J. Windsperger (Josef); G.W.J. Hendrikse (George); G. Cliquet (Gérard); T. Ehrmann (Thomas)

2017-01-01

textabstractThis special issue focuses on empirical and theoretical papers that help us to better understand the strategy and governance of entrepreneurial networks, such as franchise chains, alliances, and cooperative networks. The following central themes are covered: (I) Which formal governance

Concepts of formal concept analysis

Science.gov (United States)

Žáček, Martin; Homola, Dan; Miarka, Rostislav

2017-07-01

The aim of this article is apply of Formal Concept Analysis on concept of world. Formal concept analysis (FCA) as a methodology of data analysis, information management and knowledge representation has potential to be applied to a verity of linguistic problems. FCA is mathematical theory for concepts and concept hierarchies that reflects an understanding of concept. Formal concept analysis explicitly formalizes extension and intension of a concept, their mutual relationships. A distinguishing feature of FCA is an inherent integration of three components of conceptual processing of data and knowledge, namely, the discovery and reasoning with concepts in data, discovery and reasoning with dependencies in data, and visualization of data, concepts, and dependencies with folding/unfolding capabilities.

Network connectivity value.

Science.gov (United States)

Dragicevic, Arnaud; Boulanger, Vincent; Bruciamacchie, Max; Chauchard, Sandrine; Dupouey, Jean-Luc; Stenger, Anne

2017-04-21

In order to unveil the value of network connectivity, we formalize the construction of ecological networks in forest environments as an optimal control dynamic graph-theoretic problem. The network is based on a set of bioreserves and patches linked by ecological corridors. The node dynamics, built upon the consensus protocol, form a time evolutive Mahalanobis distance weighted by the opportunity costs of timber production. We consider a case of complete graph, where the ecological network is fully connected, and a case of incomplete graph, where the ecological network is partially connected. The results show that the network equilibrium depends on the size of the reception zone, while the network connectivity depends on the environmental compatibility between the ecological areas. Through shadow prices, we find that securing connectivity in partially connected networks is more expensive than in fully connected networks, but should be undertaken when the opportunity costs are significant. Copyright © 2017 Elsevier Ltd. All rights reserved.

The future of network governance research

DEFF Research Database (Denmark)

Lewis, Jenny

2011-01-01

that comprises it. The main theoretical and empirical approaches that have been used to guide it to date are then briefly described, emphasizing recent debates about interpretivism and decentring. Next, it suggests that a robust and interesting future for network governance requires diversity, rather than...... adherence to a single approach. It is argued that more sophisticated approaches for examining network governance are fashioned through a synthesis of ideas and methods to create an analysis of networks as networks. This is especially the case where some formal analysis of network structure is used...

Critical formalism or digital biomorphology. The contemporary architecture formal dilema

Directory of Open Access Journals (Sweden)

Beatriz Villanueva Cajide

2018-05-01

Full Text Available With the dawn of digital media the architecture’s formal possibilities reached a level unknown before. The Guggenheim Museo branch in Bilbao appears in 1993 as the materialisation of the possibilities of the use of digital tools in architecture’s design, starting the development of a digital based architecture which currently has reached an exhaustion level that is evident in the repetition biomorphologic shapes emerged from the digital determinism to which some contemporary architectural practices have converged. While the digitalisation of the architectural process is irreversible and desirable, it is necessary to rethink the terms of this collaboration beyond the possibilities of the digital tools themselves. This article proposes to analyse seven texts written in the very moment when digitalisation became a real possibility, between Gehry’s conception of the Guggenheim Museum in 1992 and the Congress on Morphogenesis hold in the Architectural Association in 2004, in order to explore the possibility of reversing the process that has led to the formal exhaustion of digital architecture, from the acceptance of incorporating strategies coming from a contemporary critical formalism.

A Secure Key Establishment Protocol for ZigBee Wireless Sensor Networks

DEFF Research Database (Denmark)

Yuksel, Ender; Nielson, Hanne Riis; Nielson, Flemming

2009-01-01

ZigBee is a wireless sensor network standard that defines network and application layers on top of IEEE 802.15.4’s physical and medium access control layers. In the latest version of ZigBee, enhancements are prescribed for the security sublayer but we show in this paper that problems persist....... In particular we show that the End-to-End Application Key Establishment Protocol is flawed and we propose a secure protocol instead. We do so by using formal verification techniques based on static program analysis and process algebras. We present a way of using formal methods in wireless network security......, and propose a secure key establishment protocol for ZigBee networks....

Y-formalism and b ghost in the non-minimal pure spinor formalism of superstrings

International Nuclear Information System (INIS)

Oda, Ichiro; Tonin, Mario

2007-01-01

We present the Y-formalism for the non-minimal pure spinor quantization of superstrings. In the framework of this formalism we compute, at the quantum level, the explicit form of the compound operators involved in the construction of the b ghost, their normal-ordering contributions and the relevant relations among them. We use these results to construct the quantum-mechanical b ghost in the non-minimal pure spinor formalism. Moreover we show that this non-minimal b ghost is cohomologically equivalent to the non-covariant b ghost

Geometry and Formal Linguistics.

Science.gov (United States)

Huff, George A.

This paper presents a method of encoding geometric line-drawings in a way which allows sets of such drawings to be interpreted as formal languages. A characterization of certain geometric predicates in terms of their properties as languages is obtained, and techniques usually associated with generative grammars and formal automata are then applied…

Optimization of temporal networks under uncertainty

CERN Document Server

Wiesemann, Wolfram

2012-01-01

Many decision problems in Operations Research are defined on temporal networks, that is, workflows of time-consuming tasks whose processing order is constrained by precedence relations. For example, temporal networks are used to model projects, computer applications, digital circuits and production processes. Optimization problems arise in temporal networks when a decision maker wishes to determine a temporal arrangement of the tasks and/or a resource assignment that optimizes some network characteristic (e.g. the time required to complete all tasks). The parameters of these optimization probl

A Formal Valuation Framework for Emotions and Their Control.

Science.gov (United States)

Huys, Quentin J M; Renz, Daniel

2017-09-15

Computational psychiatry aims to apply mathematical and computational techniques to help improve psychiatric care. To achieve this, the phenomena under scrutiny should be within the scope of formal methods. As emotions play an important role across many psychiatric disorders, such computational methods must encompass emotions. Here, we consider formal valuation accounts of emotions. We focus on the fact that the flexibility of emotional responses and the nature of appraisals suggest the need for a model-based valuation framework for emotions. However, resource limitations make plain model-based valuation impossible and require metareasoning strategies to apportion cognitive resources adaptively. We argue that emotions may implement such metareasoning approximations by restricting the range of behaviors and states considered. We consider the processes that guide the deployment of the approximations, discerning between innate, model-free, heuristic, and model-based controllers. A formal valuation and metareasoning framework may thus provide a principled approach to examining emotions. Copyright © 2017 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

'No man is an island'. Testing the specific role of social isolation in formal thought disorder.

Science.gov (United States)

de Sousa, Paulo; Spray, Amy; Sellwood, William; Bentall, Richard P

2015-12-15

Recent work has focused on the role of the environment in psychosis with emerging evidence that specific psychotic experiences are associated with specific types of adversity. One risk factor that has been often associated with psychosis is social isolation, with studies identifying isolation as an important feature of prodromal psychosis and others reporting that social networks of psychotic patients are smaller and less dense than those of healthy individuals. In the present study, we tested a prediction that social isolation would be specifically associated with formal thought disorder. 80 patients diagnosed with psychosis-spectrum disorder and 30 healthy participants were assessed for formal thought disorder with speech samples acquired during an interview that promoted personal disclosure and an interview targeting everyday topics. Social isolation was significantly associated with formal thought disorder in the neutral interview and in the salient interview, even when controlling for comorbid hallucinations, delusions and suspiciousness. Hallucinations, delusions and suspiciousness were not associated with social isolation when formal thought disorder was controlled for. Formal thought disorder is robustly and specifically associated with social isolation. Social cognitive mechanisms and processes are discussed which may explain this relationship as well as implications for clinical practice and future research. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Network Formation under the Threat of Disruption

NARCIS (Netherlands)

Hoyer, B.

2013-01-01

The studies in this thesis are focused on the impact the presence of a network disruptor has on network formation models. In particular, we build two theoretical models to study the effect of network disruption on network formation and test the effect network disruption has on equilibrium selection

Formal Testing of Correspondence Carrying Software

NARCIS (Netherlands)

Bujorianu, M.C.; Bujorianu, L.M.; Maharaj, S.

2008-01-01

Nowadays formal software development is characterised by use of multitude formal specification languages. Test case generation from formal specifications depends in general on a specific language, and, moreover, there are competing methods for each language. There is a need for a generic approach to

The influence of formal institutions on the internationalization of companies in an emerging country

Directory of Open Access Journals (Sweden)

Jefferson Marlon Monticelli

2017-07-01

Full Text Available Purpose – The goal of this study is to use the institution-based view as the background for an investigation of how formal institutions influence the internationalization processes of firms from an emerging economy. Design/methodology/approach – Our case study is based on semistructured interviews with twenty-one representatives of formal institutions and firms in the Brazilian wine industry. Findings – It was noted that formal institutions have positive influences on the internationalization of Brazilian wineries by providing learning, relationship networks, intelligence about foreign markets, costs reduction, internationalization of business processes, and by promoting the home country’s image as a wine producer in foreign markets, and as a recognized supplier to the domestic market. They also have negative influences, as excessive bureaucracy, strikes, erection of legal barriers to trade with other countries, insufficient technical knowledge, high taxes, and favoritism benefiting the largest wine producers in the industry. Originality/value – The paper closes with suggestions for future research on how phenomena such as the relationship strategies established by the wineries impact upon internationalization and how decisions of a political nature made by formal institutions influence the wine industry, providing a new outlook on the internationalization of these firms.

Formal model-based development for safety-critical embedded software

International Nuclear Information System (INIS)

Kim, Jin Hyun; Choi, Jin Young

2005-01-01

Safety-critical embedded software for nuclear I and C system is developed under the safety and reliability regulation. Programmable logic controller(PLC) is a computer system for instrumentation and control (I and C) system of nuclear power plants. PLC consists of various I and C logics in software, including real-time operating system (RTOS). Hence, errors related with RTOS should be detected and eliminated in development processes. Practically, the verification and validation for errors in RTOS is performed in test procedure, in which a lot of tasks for testing are embedded in RTOS and are running under a test environments. But the test process can not be enough to guarantee the safety and reliability of RTOS. Therefore, in this paper, we introduce to applying formal methods with the development of software for the PLC. We particularity apply formal methods to a development of RTOS for PLC, which is a safety critical level. In this development, we use the state charts of I-Logix to specify and verification and model checking to verify the specification

Formal model-based development for safety-critical embedded software

Energy Technology Data Exchange (ETDEWEB)

Kim, Jin Hyun; Choi, Jin Young [Korea University, seoul (Korea, Republic of)

2005-11-15

Safety-critical embedded software for nuclear I and C system is developed under the safety and reliability regulation. Programmable logic controller(PLC) is a computer system for instrumentation and control (I and C) system of nuclear power plants. PLC consists of various I and C logics in software, including real-time operating system (RTOS). Hence, errors related with RTOS should be detected and eliminated in development processes. Practically, the verification and validation for errors in RTOS is performed in test procedure, in which a lot of tasks for testing are embedded in RTOS and are running under a test environments. But the test process can not be enough to guarantee the safety and reliability of RTOS. Therefore, in this paper, we introduce to applying formal methods with the development of software for the PLC. We particularity apply formal methods to a development of RTOS for PLC, which is a safety critical level. In this development, we use the state charts of I-Logix to specify and verification and model checking to verify the specification.

The coaching network: A model for conducting and managing

International Nuclear Information System (INIS)

Rudd, J.G.; Smith, E.E.

1991-01-01

The Coaching Network is a mechanism for continually instructing and providing feedback to the learner during and after formal instruction. Six conditions necessary for the implementation of a Coaching Network are discussed. Use of the Coaching Network leads to improved performance, independent learning, improved skill/knowledge, and goal/objective setting

Cambio tecnológico y redes formales e informales en empresas argentinas

Directory of Open Access Journals (Sweden)

Cecilia Senen González

1995-12-01

Full Text Available Argentina's return to productive investment is largely concentrated in the privatized companies, which change their technology in accordance with two opposed modalities: systematic modernization or revalorization of the existing equipment. The first variation -exemplified by the national telephone network - renders the knowledge and experience accumulated by the State-owned company obsolete, and it is for this reason -we argue- that the new owners of the telephone company invest massively in the transference of technology, in the development of training schemes and in the creation of formal educational cooperation networks for training personnel. In the second variation pre-existing knowledge is still necessary to the extent that de-burocratization and the reassessment of responsibilities have become practically synonymous

Formal Specification and Validation of Secure Connection Establishment in a Generic Access Network Scenario

DEFF Research Database (Denmark)

Fleischer, Paul; Kristensen, Lars Michael

2008-01-01

The Generic Access Network (GAN) architecture is defined by the 3rd Generation Partnership Project (3GPP), and allows telephone services, such as SMS and voice-calls, to be accessed via generic IP networks. The main usage of this is to allow mobile phones to use WiFi in addition to the usual GSM...... network. The GAN specification relies on the Internet Protocol Security layer (IPSec) and the Internet Key Exchange protocol (IKEv2) to provide encryption across IP networks, and thus avoid compromising the security of the telephone networks. The detailed usage of these two Internet protocols (IPSec...

Sea Turtle Stranding Network Reports

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The Sea Turtle Stranding and Salvage Network (STSSN) was formally established in 1980 to collect information on and document the stranding of marine turtles along...

Formal analysis of design process dynamics

NARCIS (Netherlands)

Bosse, T.; Jonker, C.M.; Treur, J.

2010-01-01

This paper presents a formal analysis of design process dynamics. Such a formal analysis is a prerequisite to come to a formal theory of design and for the development of automated support for the dynamics of design processes. The analysis was geared toward the identification of dynamic design

Formal Analysis of Design Process Dynamics

NARCIS (Netherlands)

Bosse, T.; Jonker, C.M.; Treur, J.

2010-01-01

This paper presents a formal analysis of design process dynamics. Such a formal analysis is a prerequisite to come to a formal theory of design and for the development of automated support for the dynamics of design processes. The analysis was geared toward the identification of dynamic design

Synchronisation of networked Kuramoto oscillators under stable Lévy noise

Science.gov (United States)

Kalloniatis, Alexander C.; Roberts, Dale O.

2017-01-01

We study the Kuramoto model on several classes of network topologies examining the dynamics under the influence of Lévy noise. Such noise exhibits heavier tails than Gaussian and allows us to understand how 'shocks' influence the individual oscillator and collective system behaviour. Skewed α-stable Lévy noise, equivalent to fractional diffusion perturbations, are considered. We perform numerical simulations for Erdős-Rényi (ER) and Barabási-Albert (BA) scale free networks of size N = 1000 while varying the Lévy index α for the noise. We find that synchrony now assumes a surprising variety of forms, not seen for Gaussian-type noise, and changing with α: a noise-generated drift, a smooth α dependence of the point of cross-over of ER and BA networks in the degree of synchronisation, and a severe loss of synchronisation at low values of α. We also show that this robustness of the BA network across most values of α can also be understood as a consequence of the Laplacian of the graph working within the fractional Fokker-Planck equation of the linearised system, close to synchrony, with both eigenvalues and eigenvectors alternately contributing in different regimes of α.

Formalizing the concept of sound.

Energy Technology Data Exchange (ETDEWEB)

Kaper, H. G.; Tipei, S.

1999-08-03

The notion of formalized music implies that a musical composition can be described in mathematical terms. In this article we explore some formal aspects of music and propose a framework for an abstract approach.

Formal Analysis of Domain Models

National Research Council Canada - National Science Library

Bharadwaj, Ramesh

2002-01-01

Recently, there has been a great deal of interest in the application of formal methods, in particular, precise formal notations and automatic analysis tools for the creation and analysis of requirements specifications (i.e...

A social network model of supply chain management in formal and informal inter-firm engagement

Directory of Open Access Journals (Sweden)

Lokhman Hakim Osman

2015-12-01

Full Text Available Background: This research looks into the different effects of firms' network structural positions in an upstream supply network upon the firms' level of relational capital outcomes.  Previous research has largely focus on the context of decentralized network structure.  However, the supply network is a centralized network because of the existence of the focal firm.  The existence of the focal firm may influence the impact of relational capital outcomes.  Methods: The objective of this research is to determine the type of network structural positions required to obtain reasonable relational capital outcome in upstream supply network.  Results and conclusions: This study found that, network structural positions i.e. betweeness centrality contributed to firms' level of relational capital influence. In conclusion, firms, embedded in upstream supply network benefits differently in terms of relational capital through different degree of embeddedness.  Firms' resources should be re-aligned to match the benefits with the different network structural positions.

Modelling aspects of distributed processing in telecommunication networks

NARCIS (Netherlands)

Tomasgard, A; Audestad, JA; Dye, S; Stougie, L; van der Vlerk, MH; Wallace, SW

1998-01-01

The purpose of this paper is to formally describe new optimization models for telecommunication networks with distributed processing. Modem distributed networks put more focus on the processing of information and less on the actual transportation of data than we are traditionally used to in

Formal Methods for Life-Critical Software

Science.gov (United States)

Butler, Ricky W.; Johnson, Sally C.

1993-01-01

The use of computer software in life-critical applications, such as for civil air transports, demands the use of rigorous formal mathematical verification procedures. This paper demonstrates how to apply formal methods to the development and verification of software by leading the reader step-by-step through requirements analysis, design, implementation, and verification of an electronic phone book application. The current maturity and limitations of formal methods tools and techniques are then discussed, and a number of examples of the successful use of formal methods by industry are cited.

Target-space duality between simple compact Lie groups and Lie algebras under the Hamiltonian formalism. Pt. 1. Remnants of duality at the classic level

International Nuclear Information System (INIS)

Alvarez, O.; Liu Chienhao

1996-01-01

It has been suggested that a possible classical remnant of the phenomenon of target-space duality (T-duality) would be the equivalence of the classical string Hamiltonian systems. Given a simple compact Lie group G with a bi-invariant metric and a generating function Γ suggested in the physics literature, we follow the above line of thought and work out the canonical transformation Φ generated by Γ together with an Ad-invariant metric and a B-field on the associated Lie algebra g of G so that G and g form a string target-space dual pair at the classical level under the Hamiltonian formalism. In this article, some general features of this Hamiltonian setting are discussed. We study properties of the canonical transformation Φ including a careful analysis of its domain and image. The geometry of the T-dual structure on g is lightly touched. We leave the task of tracing back the Hamiltonian formalism at the quantum level to the sequel of this paper. (orig.). With 4 figs

Formal Modeling of Greedy Nodes in 802.15.4 WSN

Directory of Open Access Journals (Sweden)

Youcef Hammal

2015-06-01

Full Text Available This paper deals with formal specification of the non-slotted CSMA/CA protocol in wireless sensor networks(WSN whose some nodes own a greedy behavior. This protocol requires sensor nodes to wait some time before initiating a transmission, whereas greedy nodes may try to reduce their waiting duration, which may penalize other nodes. To analyze their impact on WSN mode in operation, we use timed automata of the model-checker UPPAAL to capture the abstract behavior of communication medium, sane, and greedy nodes in WSN. This enables the use of analysis tools to check whether these models satisfy intended properties.

Scalable Techniques for Formal Verification

CERN Document Server

Ray, Sandip

2010-01-01

This book presents state-of-the-art approaches to formal verification techniques to seamlessly integrate different formal verification methods within a single logical foundation. It should benefit researchers and practitioners looking to get a broad overview of the spectrum of formal verification techniques, as well as approaches to combining such techniques within a single framework. Coverage includes a range of case studies showing how such combination is fruitful in developing a scalable verification methodology for industrial designs. This book outlines both theoretical and practical issue

Multilayer Brain Networks

Science.gov (United States)

Vaiana, Michael; Muldoon, Sarah Feldt

2018-01-01

The field of neuroscience is facing an unprecedented expanse in the volume and diversity of available data. Traditionally, network models have provided key insights into the structure and function of the brain. With the advent of big data in neuroscience, both more sophisticated models capable of characterizing the increasing complexity of the data and novel methods of quantitative analysis are needed. Recently, multilayer networks, a mathematical extension of traditional networks, have gained increasing popularity in neuroscience due to their ability to capture the full information of multi-model, multi-scale, spatiotemporal data sets. Here, we review multilayer networks and their applications in neuroscience, showing how incorporating the multilayer framework into network neuroscience analysis has uncovered previously hidden features of brain networks. We specifically highlight the use of multilayer networks to model disease, structure-function relationships, network evolution, and link multi-scale data. Finally, we close with a discussion of promising new directions of multilayer network neuroscience research and propose a modified definition of multilayer networks designed to unite and clarify the use of the multilayer formalism in describing real-world systems.

Suppression of anomalous synchronization and nonstationary behavior of neural network under small-world topology

Science.gov (United States)

Boaretto, B. R. R.; Budzinski, R. C.; Prado, T. L.; Kurths, J.; Lopes, S. R.

2018-05-01

It is known that neural networks under small-world topology can present anomalous synchronization and nonstationary behavior for weak coupling regimes. Here, we propose methods to suppress the anomalous synchronization and also to diminish the nonstationary behavior occurring in weakly coupled neural network under small-world topology. We consider a network of 2000 thermally sensitive identical neurons, based on the model of Hodgkin-Huxley in a small-world topology, with the probability of adding non local connection equal to p = 0 . 001. Based on experimental protocols to suppress anomalous synchronization, as well as nonstationary behavior of the neural network dynamics, we make use of (i) external stimulus (pulsed current); (ii) biologic parameters changing (neuron membrane conductance changes); and (iii) body temperature changes. Quantification analysis to evaluate phase synchronization makes use of the Kuramoto's order parameter, while recurrence quantification analysis, particularly the determinism, computed over the easily accessible mean field of network, the local field potential (LFP), is used to evaluate nonstationary states. We show that the methods proposed can control the anomalous synchronization and nonstationarity occurring for weak coupling parameter without any effect on the individual neuron dynamics, neither in the expected asymptotic synchronized states occurring for large values of the coupling parameter.

A Survey of Formal Methods in Software Development

DEFF Research Database (Denmark)

Bjørner, Dines

2012-01-01

The use of formal methods and formal techniques in industry is steadily growing. In this survey we shall characterise what we mean by software development and by a formal method; briefly overview a history of formal specification languages - some of which are: VDM (Vienna Development Method, 1974...... need for multi-language formalisation (Petri Nets, MSC, StateChart, Temporal Logics); the sociology of university and industry acceptance of formal methods; the inevitability of the use of formal software development methods; while referring to seminal monographs and textbooks on formal methods....

Modeling the Propagation of Mobile Phone Virus under Complex Network

Science.gov (United States)

Yang, Wei; Wei, Xi-liang; Guo, Hao; An, Gang; Guo, Lei

2014-01-01

Mobile phone virus is a rogue program written to propagate from one phone to another, which can take control of a mobile device by exploiting its vulnerabilities. In this paper the propagation model of mobile phone virus is tackled to understand how particular factors can affect its propagation and design effective containment strategies to suppress mobile phone virus. Two different propagation models of mobile phone viruses under the complex network are proposed in this paper. One is intended to describe the propagation of user-tricking virus, and the other is to describe the propagation of the vulnerability-exploiting virus. Based on the traditional epidemic models, the characteristics of mobile phone viruses and the network topology structure are incorporated into our models. A detailed analysis is conducted to analyze the propagation models. Through analysis, the stable infection-free equilibrium point and the stability condition are derived. Finally, considering the network topology, the numerical and simulation experiments are carried out. Results indicate that both models are correct and suitable for describing the spread of two different mobile phone viruses, respectively. PMID:25133209

CGBayesNets: conditional Gaussian Bayesian network learning and inference with mixed discrete and continuous data.

Science.gov (United States)

McGeachie, Michael J; Chang, Hsun-Hsien; Weiss, Scott T

2014-06-01

Bayesian Networks (BN) have been a popular predictive modeling formalism in bioinformatics, but their application in modern genomics has been slowed by an inability to cleanly handle domains with mixed discrete and continuous variables. Existing free BN software packages either discretize continuous variables, which can lead to information loss, or do not include inference routines, which makes prediction with the BN impossible. We present CGBayesNets, a BN package focused around prediction of a clinical phenotype from mixed discrete and continuous variables, which fills these gaps. CGBayesNets implements Bayesian likelihood and inference algorithms for the conditional Gaussian Bayesian network (CGBNs) formalism, one appropriate for predicting an outcome of interest from, e.g., multimodal genomic data. We provide four different network learning algorithms, each making a different tradeoff between computational cost and network likelihood. CGBayesNets provides a full suite of functions for model exploration and verification, including cross validation, bootstrapping, and AUC manipulation. We highlight several results obtained previously with CGBayesNets, including predictive models of wood properties from tree genomics, leukemia subtype classification from mixed genomic data, and robust prediction of intensive care unit mortality outcomes from metabolomic profiles. We also provide detailed example analysis on public metabolomic and gene expression datasets. CGBayesNets is implemented in MATLAB and available as MATLAB source code, under an Open Source license and anonymous download at http://www.cgbayesnets.com.

Transforming process models : executable rewrite rules versus a formalized Java program

NARCIS (Netherlands)

Van Gorp, P.M.E.; Eshuis, H.; Petriu, D.C.; Rouquette, N.

2010-01-01

In the business process management community, transformations for process models are usually programmed using imperative languages (such as Java). The underlying mapping rules tend to be documented using informal visual rules whereas they tend to be formalized using mathematical set constructs. In

Transforming process models : executable rewrite rules versus a formalized Java program

NARCIS (Netherlands)

Van Gorp, P.M.E.; Eshuis, H.

2010-01-01

In the business process management community, transformations for process models are usually programmed using imperative languages. The underlying mapping rules tend to be documented using informal visual rules whereas they tend to be formalized using mathematical set constructs. In the Graph and

Formalization of Informal Waste Pickers’ Cooperatives in Blantyre, Malawi: A Feasibility Assessment

Directory of Open Access Journals (Sweden)

Cidrick Kasinja

2018-04-01

Full Text Available Poor road networks, inadequate financial resources and low levels of political will mean that many developing countries, especially their unplanned settlements, struggle with solid waste management. Recently, Informal Waste Pickers (IWPs have been incorporated into waste management cooperatives by formalizing their operations as a strategy to improve the quality and efficiency of waste management in such areas. This study was conducted in Zingwangwa, an unplanned settlement in Blantyre, Malawi, to understand whether the formalization of IWPs into cooperatives could be effective and/or accepted as a way of managing Municipal Solid Waste in unplanned urban settlements in Malawi. Thirty-four IWPs in Zingwangwa were identified and interviewed using a structured questionnaire; personnel from the Blantyre City Council and middlemen were interviewed as key informants. We determined that IWPs experience challenges in all dimensions of their lives: low material prices with exploitative price fluctuations, negative public perception and a lack of transportation are a few of their struggles. Furthermore, a fear of decreased income, conflicts during proceeds sharing, free riding behaviors and an attachment to their independence mean that IWPs are unlikely to form a cooperative on their own though some would be willing to join if a third party initiated the formalization process.

On the Conditional Entropy of Wireless Networks

DEFF Research Database (Denmark)

Coon, Justin P.; Badiu, Mihai Alin; Gündüz, Deniz

2018-01-01

The characterization of topological uncertainty in wireless networks using the formalism of graph entropy has received interest in the spatial networks community. In this paper, we develop lower bounds on the entropy of a wireless network by conditioning on potential network observables. Two...... approaches are considered: 1) conditioning on subgraphs, and 2) conditioning on node positions. The first approach is shown to yield a relatively tight bound on the network entropy. The second yields a loose bound, in general, but it provides insight into the dependence between node positions (modelled using...

Formalizing Probabilistic Safety Claims

Science.gov (United States)

Herencia-Zapana, Heber; Hagen, George E.; Narkawicz, Anthony J.

2011-01-01

A safety claim for a system is a statement that the system, which is subject to hazardous conditions, satisfies a given set of properties. Following work by John Rushby and Bev Littlewood, this paper presents a mathematical framework that can be used to state and formally prove probabilistic safety claims. It also enables hazardous conditions, their uncertainties, and their interactions to be integrated into the safety claim. This framework provides a formal description of the probabilistic composition of an arbitrary number of hazardous conditions and their effects on system behavior. An example is given of a probabilistic safety claim for a conflict detection algorithm for aircraft in a 2D airspace. The motivation for developing this mathematical framework is that it can be used in an automated theorem prover to formally verify safety claims.

VRML metabolic network visualizer.

Science.gov (United States)

Rojdestvenski, Igor

2003-03-01

A successful date collection visualization should satisfy a set of many requirements: unification of diverse data formats, support for serendipity research, support of hierarchical structures, algorithmizability, vast information density, Internet-readiness, and other. Recently, virtual reality has made significant progress in engineering, architectural design, entertainment and communication. We experiment with the possibility of using the immersive abstract three-dimensional visualizations of the metabolic networks. We present the trial Metabolic Network Visualizer software, which produces graphical representation of a metabolic network as a VRML world from a formal description written in a simple SGML-type scripting language.

Towards a Formal Model of Privacy-Sensitive Dynamic Coalitions

Directory of Open Access Journals (Sweden)

Sebastian Bab

2012-04-01

Full Text Available The concept of dynamic coalitions (also virtual organizations describes the temporary interconnection of autonomous agents, who share information or resources in order to achieve a common goal. Through modern technologies these coalitions may form across company, organization and system borders. Therefor questions of access control and security are of vital significance for the architectures supporting these coalitions. In this paper, we present our first steps to reach a formal framework for modeling and verifying the design of privacy-sensitive dynamic coalition infrastructures and their processes. In order to do so we extend existing dynamic coalition modeling approaches with an access-control-concept, which manages access to information through policies. Furthermore we regard the processes underlying these coalitions and present first works in formalizing these processes. As a result of the present paper we illustrate the usefulness of the Abstract State Machine (ASM method for this task. We demonstrate a formal treatment of privacy-sensitive dynamic coalitions by two example ASMs which model certain access control situations. A logical consideration of these ASMs can lead to a better understanding and a verification of the ASMs according to the aspired specification.

Enhancing network performance under single link failure with AS-disjoint BGP extension

DEFF Research Database (Denmark)

Manolova, Anna Vasileva; Romeral, S.; Ruepp, Sarah Renée

2009-01-01

In this paper we propose an enhancement of the BGP protocol for obtaining AS-disjoint paths in GMPLS multi-domain networks. We evaluate the benefits of having AS-disjoint paths under single inter-domain link failure for two main applications: routing of future connection requests during routing...... protocol re-convergence and applying multi-domain restoration as survivability mechanism in case of a single link failure. The proposed BGP modification is a simple and effective solution for disjoint path selection in connection-oriented multi-domain networks. Our results show that applying the proper...

A Formal Verification Method of Function Block Diagram

International Nuclear Information System (INIS)

Koh, Kwang Yong; Seong, Poong Hyun; Jee, Eun Kyoung; Jeon, Seung Jae; Park, Gee Yong; Kwon, Kee Choon

2007-01-01

Programmable Logic Controller (PLC), an industrial computer specialized for real-time applications, is widely used in diverse control systems in chemical processing plants, nuclear power plants or traffic control systems. As a PLC is often used to implement safety, critical embedded software, rigorous safety demonstration of PLC code is necessary. Function block diagram (FBD) is a standard application programming language for the PLC and currently being used in the development of a fully-digitalized reactor protection system (RPS), which is called the IDiPS, under the KNICS project. Therefore, verification issue of FBD programs is a pressing problem, and hence is of great importance. In this paper, we propose a formal verification method of FBD programs; we defined FBD programs formally in compliance with IEC 61131-3, and then translate the programs into Verilog model, and finally the model is verified using a model checker SMV. To demonstrate the feasibility and effective of this approach, we applied it to IDiPS which currently being developed under KNICS project. The remainder of this paper is organized as follows. Section 2 briefly describes Verilog and Cadence SMV. In Section 3, we introduce FBD2V which is a tool implemented to support the proposed FBD verification framework. A summary and conclusion are provided in Section 4

Augmenting Reality and Formality of Informal and Non-Formal Settings to Enhance Blended Learning

Science.gov (United States)

Pérez-Sanagustin, Mar; Hernández-Leo, Davinia; Santos, Patricia; Kloos, Carlos Delgado; Blat, Josep

2014-01-01

Visits to museums and city tours have been part of higher and secondary education curriculum activities for many years. However these activities are typically considered "less formal" when compared to those carried out in the classroom, mainly because they take place in informal or non-formal settings. Augmented Reality (AR) technologies…

Job Search, Networks, and Labor Market Performance of Immigrants

OpenAIRE

Arceo-Gómez, Eva Olimpia

2012-01-01

We develop an on-the-job search model in which immigrants search for jobs through formal channels or networks, and the quality of job offers differs across search methods. The model predicts networks unambiguously lead to a larger share of network jobs in job-to-job transitions, whereas the effect is ambiguous in unemployment-to-job transitions.

Sustainable and Resilient Supply Chain Network Design under Disruption Risks

Directory of Open Access Journals (Sweden)

Sonia Irshad Mari

2014-09-01

Full Text Available Sustainable supply chain network design is a rich area for academic research that is still in its infancy and has potential to affect supply chain performance. Increasing regulations for carbon and waste management are forcing firms to consider their supply chains from ecological and social objectives, but in reality, however, facilities and the links connecting them are disrupted from time to time, due to poor weather, natural or manmade disasters or a combination of any other factors. Supply chain systems drop their sustainability objectives while coping with these unexpected disruptions. Hence, the new challenges for supply chain managers are to design an efficient and effective supply chain network that will be resilient enough to bounce back from any disruption and that also should have sufficient vigilance to offer same sustainability under a disruption state. This paper focuses on ecological sustainability, because an environmental focus in a supply chain system is more important and also links with other pillars of sustainability, as the products need to be produced, packed and transported in an ethical way, which should not harm social balance and the environment. Owing to importance of the considered issue, this paper attempts to introduce a network optimization model for a sustainable and resilient supply chain network by incorporating (1 sustainability via carbon emissions and embodied carbon footprints and (2 resilience by incorporating location-specific risks. The proposed goal programming (GP model optimizes the total cost, while considering the resilience and sustainability of the supply chain network.

Superfield formalism

Indian Academy of Sciences (India)

dimensional superfields, is a clear signature of the presence of the (anti-)BRST invariance in the original. 4D theory. Keywords. Non-Abelian 1-form gauge theory; Dirac fields; (anti-)Becchi–Roucet–Stora–. Tyutin invariance; superfield formalism; ...

Review of Literature on Mentorship Networks in Medicine: Where Are We Now and Where Are We Going?

Science.gov (United States)

Mickelson, Jennifer Judith

Mentorship is imperative in medical training and conceptual frameworks for mentoring continue to evolve. This study is an integrated review of the literature on mentoring networks. A systematic review of the literature on mentoring networks identified 943 articles from multiple databases. 24 relevant articles under went qualitative analysis. An iterative approach was taken to formulate themes, subthemes and codes. Three major themes were identified. The first theme was that group or peer networks meet evolving and dynamic or changing needs through training and career development. A prominent subtheme was identified which was the need for mentees to be the architects or directors of their evolving mentorship networks. The second theme identified was that mentorship networks offered a solution to barriers associated with the dyad model of mentorship. The third theme was the importance of the informality or "voluntary marriages", as distinguished from structured formal programs, to create meaningful mentorship networks. Future directions of study include examining how to empower mentees to facilitate and direct their mentorship networks.

A performance study of unmanned aerial vehicle-based sensor networks under cyber attack

Science.gov (United States)

Puchaty, Ethan M.

In UAV-based sensor networks, an emerging area of interest is the performance of these networks under cyber attack. This study seeks to evaluate the performance trade-offs from a System-of-Systems (SoS) perspective between various UAV communications architecture options in the context two missions: tracking ballistic missiles and tracking insurgents. An agent-based discrete event simulation is used to model a sensor communication network consisting of UAVs, military communications satellites, ground relay stations, and a mission control center. Network susceptibility to cyber attack is modeled with probabilistic failures and induced data variability, with performance metrics focusing on information availability, latency, and trustworthiness. Results demonstrated that using UAVs as routers increased network availability with a minimal latency penalty and communications satellite networks were best for long distance operations. Redundancy in the number of links between communication nodes helped mitigate cyber-caused link failures and add robustness in cases of induced data variability by an adversary. However, when failures were not independent, redundancy and UAV routing were detrimental in some cases to network performance. Sensitivity studies indicated that long cyber-caused downtimes and increasing failure dependencies resulted in build-ups of failures and caused significant degradations in network performance.

LHCb Online Networking Requirements

CERN Document Server

Jost, B

2003-01-01

This document describes the networking requirements of the LHCb online installation. It lists both quantitative aspects such as the number of required switch ports, as well as some qualitative features of the equipment, such as minimum buffer sizes in switches. The document comprises both the data acquisition network and the controls/general-purpose network. While the numbers represent our best current knowledge and are intended to give (in particular) network equipment manufacturers an overview of our needs, this document should not be confused with a market survey questionnaire or a formal tendering document. However the information contained in this document will be the input of any such document. A preliminary schedule for procurement and installation is also given.

Dist-Orc: A Rewriting-based Distributed Implementation of Orc with Formal Analysis

Directory of Open Access Journals (Sweden)

José Meseguer

2010-09-01

Full Text Available Orc is a theory of orchestration of services that allows structured programming of distributed and timed computations. Several formal semantics have been proposed for Orc, including a rewriting logic semantics developed by the authors. Orc also has a fully fledged implementation in Java with functional programming features. However, as with descriptions of most distributed languages, there exists a fairly substantial gap between Orc's formal semantics and its implementation, in that: (i programs in Orc are not easily deployable in a distributed implementation just by using Orc's formal semantics, and (ii they are not readily formally analyzable at the level of a distributed Orc implementation. In this work, we overcome problems (i and (ii for Orc. Specifically, we describe an implementation technique based on rewriting logic and Maude that narrows this gap considerably. The enabling feature of this technique is Maude's support for external objects through TCP sockets. We describe how sockets are used to implement Orc site calls and returns, and to provide real-time timing information to Orc expressions and sites. We then show how Orc programs in the resulting distributed implementation can be formally analyzed at a reasonable level of abstraction by defining an abstract model of time and the socket communication infrastructure, and discuss the assumptions under which the analysis can be deemed correct. Finally, the distributed implementation and the formal analysis methodology are illustrated with a case study.

MOOC & B-Learning: Students' Barriers and Satisfaction in Formal and Non-Formal Learning Environments

Science.gov (United States)

Gutiérrez-Santiuste, Elba; Gámiz-Sánchez, Vanesa-M.; Gutiérrez-Pérez, Jose

2015-01-01

The study presents a comparative analysis of two virtual learning formats: one non-formal through a Massive Open Online Course (MOOC) and the other formal through b-learning. We compare the communication barriers and the satisfaction perceived by the students (N = 249) by developing a qualitative analysis using semi-structured questionnaires and…

Ageing and Non-Formal Care for Elderly Persons in Croatia

Directory of Open Access Journals (Sweden)

Sonja Podgorelec

2007-06-01

Full Text Available Ageing and depopulation are the fundamental demographic processes in the development of the population of Croatia. In the total population in 2001 the age group encompassing persons 65 years of age and older made up 15.7% of the total population. The age structure of the population is one of the essential determinants of the quality of lives of individuals, especially within the family. Based on an analysis of demographic indicators (the population structure, the ratio of females, the ageing index, the age coefficient, average age, age-dependency ratios, marital status, and a brief review of migration history in the second half of the 20th century, the goal of this paper is to evaluate the quality of non-formal care of the elderly in relation to potential care providers. Due to ageing in the total population of Croatia, due to a reduction in the number of children per family and separate residences of adult children and their elderly parents, the circle of main care providers for the elderly has diminished. With the decrease in the number of family members, increasingly frequent forms of single-parent families and the employment of women, who were traditionally the most important providers of all forms of non-formal care, insufficient care for the elderly within families has become a problem. Despite changes in the way of life, the family is still the basic source of emotional, informational and instrumental support for elderly people. The help and support that the elderly receive from friends is roughly equal in the city and in villages, although neighbourly help is somewhat greater in non-urban areas (for example in Istria and on the islands. However, researches confirm that the social network of support and help among the rural population has changed since the nineties of the last century. To a certain extent the support of friends and neighbours may substitute the lack of care by children, but a weaker network of homes for the elderly and

Formality of the Chinese collective leadership.

Science.gov (United States)

Li, Haiying; Graesser, Arthur C

2016-09-01

We investigated the linguistic patterns in the discourse of four generations of the collective leadership of the Communist Party of China (CPC) from 1921 to 2012. The texts of Mao Zedong, Deng Xiaoping, Jiang Zemin, and Hu Jintao were analyzed using computational linguistic techniques (a Chinese formality score) to explore the persuasive linguistic features of the leaders in the contexts of power phase, the nation's education level, power duration, and age. The study was guided by the elaboration likelihood model of persuasion, which includes a central route (represented by formal discourse) versus a peripheral route (represented by informal discourse) to persuasion. The results revealed that these leaders adopted the formal, central route more when they were in power than before they came into power. The nation's education level was a significant factor in the leaders' adoption of the persuasion strategy. The leaders' formality also decreased with their increasing age and in-power times. However, the predictability of these factors for formality had subtle differences among the different types of leaders. These results enhance our understanding of the Chinese collective leadership and the role of formality in politically persuasive messages.

Phenotypic stability and plasticity in GMP-derived cells as determined by their underlying regulatory network.

Science.gov (United States)

Ramírez, Carlos; Mendoza, Luis

2018-04-01

Blood cell formation has been recognized as a suitable system to study celular differentiation mainly because of its experimental accessibility, and because it shows characteristics such as hierarchical and gradual bifurcated patterns of commitment, which are present in several developmental processes. Although hematopoiesis has been extensively studied and there is a wealth of molecular and cellular data about it, it is not clear how the underlying molecular regulatory networks define or restrict cellular differentiation processes. Here, we infer the molecular regulatory network that controls the differentiation of a blood cell subpopulation derived from the granulocyte-monocyte precursor (GMP), comprising monocytes, neutrophils, eosinophils, basophils and mast cells. We integrate published qualitative experimental data into a model to describe temporal expression patterns observed in GMP-derived cells. The model is implemented as a Boolean network, and its dynamical behavior is studied. Steady states of the network can be clearly identified with the expression profiles of monocytes, mast cells, neutrophils, basophils, and eosinophils, under wild-type and mutant backgrounds. All scripts are publicly available at https://github.com/caramirezal/RegulatoryNetworkGMPModel. lmendoza@biomedicas.unam.mx. Supplementary data are available at Bioinformatics online.

Identifiability of tree-child phylogenetic networks under a probabilistic recombination-mutation model of evolution.

Science.gov (United States)

Francis, Andrew; Moulton, Vincent

2018-06-07

Phylogenetic networks are an extension of phylogenetic trees which are used to represent evolutionary histories in which reticulation events (such as recombination and hybridization) have occurred. A central question for such networks is that of identifiability, which essentially asks under what circumstances can we reliably identify the phylogenetic network that gave rise to the observed data? Recently, identifiability results have appeared for networks relative to a model of sequence evolution that generalizes the standard Markov models used for phylogenetic trees. However, these results are quite limited in terms of the complexity of the networks that are considered. In this paper, by introducing an alternative probabilistic model for evolution along a network that is based on some ground-breaking work by Thatte for pedigrees, we are able to obtain an identifiability result for a much larger class of phylogenetic networks (essentially the class of so-called tree-child networks). To prove our main theorem, we derive some new results for identifying tree-child networks combinatorially, and then adapt some techniques developed by Thatte for pedigrees to show that our combinatorial results imply identifiability in the probabilistic setting. We hope that the introduction of our new model for networks could lead to new approaches to reliably construct phylogenetic networks. Copyright © 2018 Elsevier Ltd. All rights reserved.

Nonlinear threshold Boolean automata networks and phase transitions

OpenAIRE

Demongeot, Jacques; Sené, Sylvain

2010-01-01

In this report, we present a formal approach that addresses the problem of emergence of phase transitions in stochastic and attractive nonlinear threshold Boolean automata networks. Nonlinear networks considered are informally defined on the basis of classical stochastic threshold Boolean automata networks in which specific interaction potentials of neighbourhood coalition are taken into account. More precisely, specific nonlinear terms compose local transition functions that define locally t...

40 years of formal methods

DEFF Research Database (Denmark)

Bjørner, Dines; Havelund, Klaus

2014-01-01

In this "40 years of formal methods" essay we shall first delineate, Sect. 1, what we mean by method, formal method, computer science, computing science, software engineering, and model-oriented and algebraic methods. Based on this, we shall characterize a spectrum from specification-oriented met...

Geosciences Information Network (GIN): A modular, distributed, interoperable data network for the geosciences

Science.gov (United States)

Allison, M.; Gundersen, L. C.; Richard, S. M.; Dickinson, T. L.

2008-12-01

A coalition of the state geological surveys (AASG), the U.S. Geological Survey (USGS), and partners will receive NSF funding over 3 years under the INTEROP solicitation to start building the Geoscience Information Network (www.geoinformatics.info/gin) a distributed, interoperable data network. The GIN project will develop standardized services to link existing and in-progress components using a few standards and protocols, and work with data providers to implement these services. The key components of this network are 1) catalog system(s) for data discovery; 2) service definitions for interfaces for searching catalogs and accessing resources; 3) shared interchange formats to encode information for transmission (e.g. various XML markup languages); 4) data providers that publish information using standardized services defined by the network; and 5) client applications adapted to use information resources provided by the network. The GIN will integrate and use catalog resources that currently exist or are in development. We are working with the USGS National Geologic Map Database's existing map catalog, with the USGS National Geological and Geophysical Data Preservation Program, which is developing a metadata catalog (National Digital Catalog) for geoscience information resource discovery, and with the GEON catalog. Existing interchange formats will be used, such as GeoSciML, ChemML, and Open Geospatial Consortium sensor, observation and measurement MLs. Client application development will be fostered by collaboration with industry and academic partners. The GIN project will focus on the remaining aspects of the system -- service definitions and assistance to data providers to implement the services and bring content online - and on system integration of the modules. Initial formal collaborators include the OneGeology-Europe consortium of 27 nations that is building a comparable network under the EU INSPIRE initiative, GEON, Earthchem, and GIS software company ESRI

Credal Networks under Maximum Entropy

OpenAIRE

Lukasiewicz, Thomas

2013-01-01

We apply the principle of maximum entropy to select a unique joint probability distribution from the set of all joint probability distributions specified by a credal network. In detail, we start by showing that the unique joint distribution of a Bayesian tree coincides with the maximum entropy model of its conditional distributions. This result, however, does not hold anymore for general Bayesian networks. We thus present a new kind of maximum entropy models, which are computed sequentially. ...

A Formalization of Linkage Analysis

DEFF Research Database (Denmark)

Ingolfsdottir, Anna; Christensen, A.I.; Hansen, Jens A.

In this report a formalization of genetic linkage analysis is introduced. Linkage analysis is a computationally hard biomathematical method, which purpose is to locate genes on the human genome. It is rooted in the new area of bioinformatics and no formalization of the method has previously been ...

Utility of Interactional Strategies in the Study of Formal Operations Reasoning.

Science.gov (United States)

Siegler, Robert S.

This paper argues in favor of using interactional strategies in the study of formal operations reasoning. Interactional designs allow a convergent approach to specifying processes underlying the interaction of variables. In contrast, current methodologies contain two inherent disadvantages: they have limited utility in specifying the processes…

Thermo-Mechanical Properties of Semi-Degradable Poly(β-amino ester)-co-Methyl Methacrylate Networks under Simulated Physiological Conditions

Science.gov (United States)

Safranski, David L.; Crabtree, Jacob C.; Huq, Yameen R.; Gall, Ken

2011-01-01

Poly(β-amino ester) networks are being explored for biomedical applications, but they may lack the mechanical properties necessary for long term implantation. The objective of this study is to evaluate the effect of adding methyl methacrylate on networks' mechanical properties under simulated physiological conditions. The networks were synthesized in two parts: (1) a biodegradable crosslinker was formed from a diacrylate and amine, (2) and then varying concentrations of methyl methacrylate were added prior to photopolymerizing the network. Degradation rate, mechanical properties, and glass transition temperature were studied as a function of methyl methacrylate composition. The crosslinking density played a limited role on mechanical properties for these networks, but increasing methyl methacrylate concentration improved the toughness by several orders of magnitude. Under simulated physiological conditions, networks showed increasing toughness or sustained toughness as degradation occurred. This work establishes a method of creating degradable networks with tailorable toughness while undergoing partial degradation. PMID:21966028

Fundamentals of the Pure Spinor Formalism

CERN Document Server

Hoogeveen, Joost

2010-01-01

This thesis presents recent developments within the pure spinor formalism, which has simplified amplitude computations in perturbative string theory, especially when spacetime fermions are involved. Firstly the worldsheet action of both the minimal and the non-minimal pure spinor formalism is derived from first principles, i.e. from an action with two dimensional diffeomorphism and Weyl invariance. Secondly the decoupling of unphysical states in the minimal pure spinor formalism is proved

EMBO Course “Formal Analysis of Genetic Regulation”

CERN Document Server

1979-01-01

The E M B 0 course on "Formal Analysis of Genetic Regulation" A course entitled "Formal analysis of Genetic Regulation" was held at the University of Brussels from 6 to 16 September 1977 under the auspices of EMBO (European Molecular Biology Organization). As indicated by the title of the book (but not explicitly enough by the title of the course), the main emphasis was put on a dynamic analysis of systems using logical methods, that is, methods in which functions and variables take only a limited number of values - typically two. In this respect, this course was complementary to an EMBO course using continuous methods which was held some months later in Israel by Prof. Segel. People from four very different laboratories took an active part in teaching our course in Brussels : Drs Anne LEUSSLER and Philippe VAN HAM, from the Laboratory of Prof. Jean FLORINE (Laboratoire des Systemes logiques et numeriques, Faculte des Sciences appliquees, Universite Libre de Bruxelles). Dr Stuart KAUFFMAN (Dept. of Biochemist...

Optimal Retrofit Scheme for Highway Network under Seismic Hazards

Directory of Open Access Journals (Sweden)

Yongxi Huang

2014-06-01

Full Text Available Many older highway bridges in the United States (US are inadequate for seismic loads and could be severely damaged or collapsed in a relatively small earthquake. According to the most recent American Society of Civil Engineers’ infrastructure report card, one-third of the bridges in the US are rated as structurally deficient and many of these structurally deficient bridges are located in seismic zones. To improve this situation, at-risk bridges must be identified and evaluated and effective retrofitting programs should be in place to reduce their seismic vulnerabilities. In this study, a new retrofit strategy decision scheme for highway bridges under seismic hazards is developed and seamlessly integrate the scenario-based seismic analysis of bridges and the traffic network into the proposed optimization modeling framework. A full spectrum of bridge retrofit strategies is considered based on explicit structural assessment for each seismic damage state. As an empirical case study, the proposed retrofit strategy decision scheme is utilized to evaluate the bridge network in one of the active seismic zones in the US, Charleston, South Carolina. The developed modeling framework, on average, will help increase network throughput traffic capacity by 45% with a cost increase of only $15million for the Mw 5.5 event and increase the capacity fourfold with a cost of only $32m for the Mw 7.0 event.

Phase-response curves and synchronized neural networks.

Science.gov (United States)

Smeal, Roy M; Ermentrout, G Bard; White, John A

2010-08-12

We review the principal assumptions underlying the application of phase-response curves (PRCs) to synchronization in neuronal networks. The PRC measures how much a given synaptic input perturbs spike timing in a neural oscillator. Among other applications, PRCs make explicit predictions about whether a given network of interconnected neurons will synchronize, as is often observed in cortical structures. Regarding the assumptions of the PRC theory, we conclude: (i) The assumption of noise-tolerant cellular oscillations at or near the network frequency holds in some but not all cases. (ii) Reduced models for PRC-based analysis can be formally related to more realistic models. (iii) Spike-rate adaptation limits PRC-based analysis but does not invalidate it. (iv) The dependence of PRCs on synaptic location emphasizes the importance of improving methods of synaptic stimulation. (v) New methods can distinguish between oscillations that derive from mutual connections and those arising from common drive. (vi) It is helpful to assume linear summation of effects of synaptic inputs; experiments with trains of inputs call this assumption into question. (vii) Relatively subtle changes in network structure can invalidate PRC-based predictions. (viii) Heterogeneity in the preferred frequencies of component neurons does not invalidate PRC analysis, but can annihilate synchronous activity.

Differences in the impacts of formal and informal recreational trails on urban forest loss and tree structure.

Science.gov (United States)

Ballantyne, Mark; Pickering, Catherine Marina

2015-08-15

Recreational trails are one of the most common types of infrastructure used for nature-based activities such as hiking and mountain biking worldwide. Depending on their design, location, construction, maintenance and use, these trails differ in their environmental impacts. There are few studies, however, comparing the impacts of different trail types including between formal management-created trails and informal visitor-created trails. Although both types of trails can be found in remote natural areas, dense networks of them often occur in forests close to cities where they experience intense visitor use. To assess the relative impacts of different recreational trails in urban forests, we compared the condition of the trail surface, loss of forest strata and changes in tree structure caused by seven types of trails (total network 46.1 km) traversing 17 remnants of an endangered urban forest in Australia. After mapping and classifying all trails, we assessed their impact on the forest condition at 125 sites (15 sites per trail type, plus 15 control sites within undisturbed forest). On the trail sites, the condition of the trail surface, distance from the trail edge to four forest strata (litter, understory, midstorey and tree cover) and structure of the tree-line were assessed. Informal trails generally had poorer surface conditions and were poorly-designed and located. Per site, formal and informal trails resulted in similar loss of forest strata, with wider trails resulting in greater loss of forest. Because there were more informal trails, however, they accounted for the greatest cumulative forest loss. Structural impacts varied, with the widest informal trails and all formal hardened trails resulting in similar reductions in canopy cover and tree density but an increase in saplings. These structural impacts are likely a function of the unregulated and intense use of large informal trails, and disturbance from the construction and maintenance of formal trails

Complex Networks IX

CERN Document Server

Coronges, Kate; Gonçalves, Bruno; Sinatra, Roberta; Vespignani, Alessandro; Proceedings of the 9th Conference on Complex Networks; CompleNet 2018

2018-01-01

This book aims to bring together researchers and practitioners working across domains and research disciplines to measure, model, and visualize complex networks. It collects the works presented at the 9th International Conference on Complex Networks (CompleNet) 2018 in Boston, MA in March, 2018. With roots in physical, information and social science, the study of complex networks provides a formal set of mathematical methods, computational tools and theories to describe prescribe and predict dynamics and behaviors of complex systems. Despite their diversity, whether the systems are made up of physical, technological, informational, or social networks, they share many common organizing principles and thus can be studied with similar approaches. This book provides a view of the state-of-the-art in this dynamic field and covers topics such as group decision-making, brain and cellular connectivity, network controllability and resiliency, online activism, recommendation systems, and cyber security.

Leibniz' First Formalization of Syllogistics

DEFF Research Database (Denmark)

Robering, Klaus

2014-01-01

of letters just those which belong to the useful, i.e., valid, modes. The set of codes of valid modes turns out to be a so-called "regular" language (in the sense of formal-language-theory). Leibniz' formalization of syllogistics in his Dissertatio thus contains an estimation of the computational complexity...

Model checking optimal finite-horizon control for probabilistic gene regulatory networks.

Science.gov (United States)

Wei, Ou; Guo, Zonghao; Niu, Yun; Liao, Wenyuan

2017-12-14

Probabilistic Boolean networks (PBNs) have been proposed for analyzing external control in gene regulatory networks with incorporation of uncertainty. A context-sensitive PBN with perturbation (CS-PBNp), extending a PBN with context-sensitivity to reflect the inherent biological stability and random perturbations to express the impact of external stimuli, is considered to be more suitable for modeling small biological systems intervened by conditions from the outside. In this paper, we apply probabilistic model checking, a formal verification technique, to optimal control for a CS-PBNp that minimizes the expected cost over a finite control horizon. We first describe a procedure of modeling a CS-PBNp using the language provided by a widely used probabilistic model checker PRISM. We then analyze the reward-based temporal properties and the computation in probabilistic model checking; based on the analysis, we provide a method to formulate the optimal control problem as minimum reachability reward properties. Furthermore, we incorporate control and state cost information into the PRISM code of a CS-PBNp such that automated model checking a minimum reachability reward property on the code gives the solution to the optimal control problem. We conduct experiments on two examples, an apoptosis network and a WNT5A network. Preliminary experiment results show the feasibility and effectiveness of our approach. The approach based on probabilistic model checking for optimal control avoids explicit computation of large-size state transition relations associated with PBNs. It enables a natural depiction of the dynamics of gene regulatory networks, and provides a canonical form to formulate optimal control problems using temporal properties that can be automated solved by leveraging the analysis power of underlying model checking engines. This work will be helpful for further utilization of the advances in formal verification techniques in system biology.

Associating Human-Centered Concepts with Social Networks Using Fuzzy Sets

Science.gov (United States)

Yager, Ronald R.

The rapidly growing global interconnectivity, brought about to a large extent by the Internet, has dramatically increased the importance and diversity of social networks. Modern social networks cut across a spectrum from benign recreational focused websites such as Facebook to occupationally oriented websites such as LinkedIn to criminally focused groups such as drug cartels to devastation and terror focused groups such as Al-Qaeda. Many organizations are interested in analyzing and extracting information related to these social networks. Among these are governmental police and security agencies as well marketing and sales organizations. To aid these organizations there is a need for technologies to model social networks and intelligently extract information from these models. While established technologies exist for the modeling of relational networks [1-7] few technologies exist to extract information from these, compatible with human perception and understanding. Data bases is an example of a technology in which we have tools for representing our information as well as tools for querying and extracting the information contained. Our goal is in some sense analogous. We want to use the relational network model to represent information, in this case about relationships and interconnections, and then be able to query the social network using intelligent human-centered concepts. To extend our capabilities to interact with social relational networks we need to associate with these network human concepts and ideas. Since human beings predominantly use linguistic terms in which to reason and understand we need to build bridges between human conceptualization and the formal mathematical representation of the social network. Consider for example a concept such as "leader". An analyst may be able to express, in linguistic terms, using a network relevant vocabulary, properties of a leader. Our task is to translate this linguistic description into a mathematical formalism

Formalizing the concept phase of product development

NARCIS (Netherlands)

Schuts, M.; Hooman, J.

2015-01-01

We discuss the use of formal techniques to improve the concept phase of product realisation. As an industrial application, a new concept of interventional X-ray systems has been formalized, using model checking techniques and the simulation of formal models. cop. Springer International Publishing

Formalization of the classification pattern: survey of classification modeling in information systems engineering.

Science.gov (United States)

Partridge, Chris; de Cesare, Sergio; Mitchell, Andrew; Odell, James

2018-01-01

Formalization is becoming more common in all stages of the development of information systems, as a better understanding of its benefits emerges. Classification systems are ubiquitous, no more so than in domain modeling. The classification pattern that underlies these systems provides a good case study of the move toward formalization in part because it illustrates some of the barriers to formalization, including the formal complexity of the pattern and the ontological issues surrounding the "one and the many." Powersets are a way of characterizing the (complex) formal structure of the classification pattern, and their formalization has been extensively studied in mathematics since Cantor's work in the late nineteenth century. One can use this formalization to develop a useful benchmark. There are various communities within information systems engineering (ISE) that are gradually working toward a formalization of the classification pattern. However, for most of these communities, this work is incomplete, in that they have not yet arrived at a solution with the expressiveness of the powerset benchmark. This contrasts with the early smooth adoption of powerset by other information systems communities to, for example, formalize relations. One way of understanding the varying rates of adoption is recognizing that the different communities have different historical baggage. Many conceptual modeling communities emerged from work done on database design, and this creates hurdles to the adoption of the high level of expressiveness of powersets. Another relevant factor is that these communities also often feel, particularly in the case of domain modeling, a responsibility to explain the semantics of whatever formal structures they adopt. This paper aims to make sense of the formalization of the classification pattern in ISE and surveys its history through the literature, starting from the relevant theoretical works of the mathematical literature and gradually shifting focus

A survey of formal languages for contracts

DEFF Research Database (Denmark)

Hvitved, Tom

2010-01-01

In this short paper we present the current status on formal languages and models for contracts. By a formal model is meant an unambiguous and rigorous representation of contracts, in order to enable their automatic validation, execution, and analysis — activates that are collectively referred...... to as contract lifecycle management (CLM). We present a set of formalism requirements, which represent features that any ideal contract model should support, based on which we present a comparative survey of existing contract formalisms....

Cooperate to Validate. Observal-Net Experts' Report on Validation of Non-Formal and Informal Learning (VNIL) 2013

Science.gov (United States)

Weber Guisan, Saskia; Voit, Janine; Lengauer, Sonja; Proinger, Eva; Duvekot, Ruud; Aagaard, Kirsten

2014-01-01

The present publication is one of the outcomes of the OBSERVAL-NET project (followup of the OBSERVAL project). The main aim of OBSERVAL-NET was to set up a stakeholder centric network of organisations supporting the validation of non-formal and informal learning in Europe based on the formation of national working groups in the 8 participating…

Cooperate to Validate: OBSERVAL-NET Experts' Report on Validation of Non-Formal and Informal Learning (VNIL) 2013

Science.gov (United States)

Weber Guisan, Saskia; Voit, Janine; Lengauer, Sonja; Proinger, Eva; Duvekot, Ruud; Aagaard, Kirsten

2014-01-01

The present publication is one of the outcomes of the OBSERVAL-NET project (follow-up of the OBSERVAL project). The main aim of OBSERVAL-NET was to set up a stakeholder-centric network of organisations supporting the validation of non-formal and informal learning in Europe based on the formation of national working groups in the 8 participating…

On the Update Problems for Software Defined Networks

Directory of Open Access Journals (Sweden)

V. A. Zakharov

2014-01-01

Full Text Available The designing of network update algorithms is urgent for the development of SDN control software. A particular case of Network Update Problem is that of restoring seamlessly a given network configuration after some packet forwarding rules have been disabled (say, at the expiry of their time-outs. We study this problem in the framework of a formal model of SDN, develop correct and safe network recovering algorithms, and show that in general case there is no way to restore network configuration seamlessly without referring to priorities of packet forwarding rules.

Bandwidth provisioning in infrastructure-based wireless networks employing directional antennas

Energy Technology Data Exchange (ETDEWEB)

Hasiviswanthan, Shiva [Los Alamos National Laboratory; Zhao, Bo [PENN STATE UNIV.; Vasudevan, Sudarshan [UNIV OF MASS AMHERST; Yrgaonkar, Bhuvan [PENN STATE UNIV.

2009-01-01

Motivated by the widespread proliferation of wireless networks employing directional antennas, we study the problem of provisioning bandwidth in such networks. Given a set of subscribers and one or more access points possessing directional antennas, we formalize the problem of orienting these antennas in two fundamental settings: (1) subscriber-centric, where the objective is to fairly allocate bandwidth among the subscribers and (2) provider-centric, where the objective is to maximize the revenue generated by satisfying the bandwidth requirements of subscribers. For both the problems, we first design algorithms for a network with only one access point working under the assumption that the number of antennas does not exceed the number of noninterfering channels. Using the well-regarded lexicographic max-min fair allocation as the objective for a subscriber-centric network, we present an optimum dynamic programming algorithm. For a provider-centric network, the allocation problem turns out to be NP-hard. We present a greedy heuristic based algorithm that guarantees almost half of the optimum revenue. We later enhance both these algorithms to operate in more general networks with multiple access points and no restrictions on the relative numbers of antennas and channels. A simulation-based evaluation using OPNET demonstrates the efficacy of our approaches and provides us further in insights into these problems.

20 CFR 702.336 - Formal hearings; new issues.

Science.gov (United States)

2010-04-01

... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false Formal hearings; new issues. 702.336 Section... Procedures Formal Hearings § 702.336 Formal hearings; new issues. (a) If, during the course of the formal hearing, the evidence presented warrants consideration of an issue or issues not previously considered...

A Bayesian Network Schema for Lessening Database Inference

National Research Council Canada - National Science Library

Chang, LiWu; Moskowitz, Ira S

2001-01-01

.... The authors introduce a formal schema for database inference analysis, based upon a Bayesian network structure, which identifies critical parameters involved in the inference problem and represents...

The Interrelatedness of Formal, Non-Formal and Informal Learning: Evidence from Labour Market Program Participants

Science.gov (United States)

Cameron, Roslyn; Harrison, Jennifer L.

2012-01-01

Definitions, differences and relationships between formal, non-formal and informal learning have long been contentious. There has been a significant change in language and reference from adult education to what amounts to forms of learning categorised by their modes of facilitation. Nonetheless, there is currently a renewed interest in the…

NON-FORMAL EDUCATION, OVEREDUCATION AND WAGES

OpenAIRE

SANDRA NIETO; RAÚL RAMOS

2013-01-01

Why do overeducated workers participate in non-formal education activities? Do not they suffer from an excess of education? Using microdata from the Spanish sample of the 2007 Adult Education Survey, we have found that overeducated workers participate more than the rest in non-formal education and that they earn higher wages than overeducated workers who did not participate. This result can be interpreted as evidence that non-formal education allows overeducated workers to acquire new abiliti...

Managing Virtual Networks on Large-Scale Projects

National Research Council Canada - National Science Library

Noll, David

2006-01-01

The complexity of Boeing's 787 Program is too great for the formal planned information and communication network structure to fully meet the needs of companies, managers, and employees located throughout the world...

Strategies for a better performance of RPL under mobility in wireless sensor networks

Science.gov (United States)

Latib, Z. A.; Jamil, A.; Alduais, N. A. M.; Abdullah, J.; Audah, L. H. M.; Alias, R.

2017-09-01

A Wireless Sensor Network (WSN) is usually stationary, which the network comprises of static nodes. The increase demand for mobility in various applications such as environmental monitoring, medical, home automation, and military, raises the question how IPv6 Routing Protocol for Low-Power and Lossy Networks (RPL) would perform under these mobility applications. This paper aims to understand performance of RPL and come out with strategies for a better performance of RPL in mobility scenarios. Because of this, this paper evaluates the performance of the RPL protocol under three different scenarios: sink and sensor nodes are static, static sink and mobile sensor nodes, and sink and sensor nodes are mobile. The network scenarios are implemented in Cooja simulator. A WSN consists of 25 sensor nodes and one sink node is configured in the simulation environment. The simulation is varied over different packet rates and ContikiMAC's Clear Channel Assessment (CCA) rate. As the performance metric, RPL is evaluated in term of packet delivery ratio (PDR), power consumption and packet rates. The simulation results show RPL provides a poor PDR in the mobility scenarios when compared to the static scenario. In addition, RPL consumes more power and increases duty-cycle rate to support mobility when compared to the static scenario. Based on the findings, we suggest three strategies for a better performance of RPL in mobility scenarios. First, RPL should operates at a lower packet rates when implemented in the mobility scenarios. Second, RPL should be implemented with a higher duty-cycle rate. Lastly, the sink node should be positioned as much as possible in the center of the mobile network.

Networks amid multiple logics

DEFF Research Database (Denmark)

Bergenholtz, Carsten; Bjerregaard, Toke

The present study investigates how a high-tech-small-firm (HTSF) can carry out an inter-organizational search of actors located at universities. Responding to calls to study how firms navigate multiple institutional norms, this research examines the different strategies used by a HTSF to balance...... adopted academic norm-sets, commercial imperatives and formal regulations to support formation of networks and collaborations with universities. The findings show how the significance of weak and strong ties for the formation of collaborations and networks with universities is relative...

Using the structure of social networks to map inter-agency relationships in public health services.

Science.gov (United States)

West, Robert M; House, Allan O; Keen, Justin; Ward, Vicky L

2015-11-01

This article investigates network governance in the context of health and wellbeing services in England, focussing on relationships between managers in a range of services. There are three aims, namely to investigate, (i) the configurations of networks, (ii) the stability of network relationships over time and, (iii) the balance between formal and informal ties that underpin inter-agency relationships. Latent position cluster network models were used to characterise relationships. Managers were asked two questions, both designed to characterise informal relationships. The resulting networks differed substantially from one another in membership. Managers described networks of relationships that spanned organisational boundaries, and that changed substantially over time. The findings suggest that inter-agency co-ordination depends more on informal than on formal relationships. Copyright © 2015 Elsevier Ltd. All rights reserved.

Near-optimal Downlink precoding of a MISO system for a secondary network under the SINR constraints of a primary network

KAUST Repository

Park, Kihong

2013-04-01

In this paper, we study a multiple-input single-output cognitive radio (CR) system where only the primary base station (BS) has multiple antennas. We consider a rate maximization problem of the secondary network under signal-to-interference-plus-noise-ratio constraints on the primary network in order to guarantee the quality-of-service for the latter network. While the interference due to the secondary transmission in the conventional underlay CR approach may severely degrade the performance of the primary network, we propose a primary BS-aided approach in which the primary BS helps relay the secondary users\\' signals instead of allowing them to communicate with each other via a direct path between them. In addition, an algorithm to find a near-optimal beamforming solution at the primary BS is proposed. Finally, based on some selected numerical results, we show that the proposed scheme outperforms the conventional underlay CR configuration over a wide transmit power range. © 2013 IEEE.

A Formally Verified Decentralized Key Management Architecture for Wireless Sensor Networks

NARCIS (Netherlands)

Law, Y.W.; Corin, R.J.; Etalle, Sandro; Hartel, Pieter H.

We present a decentralized key management architecture for wireless sensor networks, covering the aspects of key deployment, key refreshment and key establishment. Our architecture is based on a clear set of assumptions and guidelines. Balance between security and energy consumption is achieved by

40 CFR 35.938-4 - Formal advertising.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 1 2010-07-01 2010-07-01 false Formal advertising. 35.938-4 Section 35... advertising. Each contract shall be awarded after formal advertising, unless negotiation is permitted in accordance with § 35.936-18. Formal advertising shall be in accordance with the following: (a) Adequate...

Seniority in projection operator formalism

International Nuclear Information System (INIS)

Ullah, N.

1976-01-01

It is shown that the concept of seniority can be introduced in projection operator formalism through the use of the operator Q, which has been defined by de-Shalit and Talmi. The usefulness of seniority concept in projection operator formalism is discussed. An example of four nucleons in j=3/2 configuration is given for illustrative purposes

A Mathematical Formalization Proposal for Business Growth

Directory of Open Access Journals (Sweden)

Gheorghe BAILESTEANU

2013-01-01

Full Text Available Economic sciences have known a spectacular evolution in the last century; beginning to use axiomatic methods, applying mathematical instruments as a decision-making tool. The quest to formalization needs to be addressed from various different angles, reducing entry and operating formal costs, increasing the incentives for firms to operate formally, reducing obstacles to their growth, and searching for inexpensive approaches through which to enforce compliancy with government regulations. This paper proposes a formalized approach to business growth, based on mathematics and logics, taking into consideration the particularities of the economic sector.

What Determines Firms’ Decisions to Formalize?

OpenAIRE

Neil McCulloch; Günther G. Schulze; Janina Voss

2010-01-01

In this paper we analyze the decision of small and micro firms to formalize, i.e. to obtain business and other licenses in rural Indonesia. We use the rural investment climate survey (RICS) that consists of non-farm rural enterprises, most of them microenterprises, and analyze the effect of formalization on tax payments, corruption, access to credit and revenue, taking into account the endogeneity of the formalization decision to such benefits and costs. We show, contrary to most of the liter...

Discrete Wigner formalism for qubits and noncontextuality of Clifford gates on qubit stabilizer states

Science.gov (United States)

Kocia, Lucas; Love, Peter

2017-12-01

We show that qubit stabilizer states can be represented by non-negative quasiprobability distributions associated with a Wigner-Weyl-Moyal formalism where Clifford gates are positive state-independent maps. This is accomplished by generalizing the Wigner-Weyl-Moyal formalism to three generators instead of two—producing an exterior, or Grassmann, algebra—which results in Clifford group gates for qubits that act as a permutation on the finite Weyl phase space points naturally associated with stabilizer states. As a result, a non-negative probability distribution can be associated with each stabilizer state's three-generator Wigner function, and these distributions evolve deterministically to one another under Clifford gates. This corresponds to a hidden variable theory that is noncontextual and local for qubit Clifford gates while Clifford (Pauli) measurements have a context-dependent representation. Equivalently, we show that qubit Clifford gates can be expressed as propagators within the three-generator Wigner-Weyl-Moyal formalism whose semiclassical expansion is truncated at order ℏ0 with a finite number of terms. The T gate, which extends the Clifford gate set to one capable of universal quantum computation, requires a semiclassical expansion of the propagator to order ℏ1. We compare this approach to previous quasiprobability descriptions of qubits that relied on the two-generator Wigner-Weyl-Moyal formalism and find that the two-generator Weyl symbols of stabilizer states result in a description of evolution under Clifford gates that is state-dependent, in contrast to the three-generator formalism. We have thus extended Wigner non-negative quasiprobability distributions from the odd d -dimensional case to d =2 qubits, which describe the noncontextuality of Clifford gates and contextuality of Pauli measurements on qubit stabilizer states.

Lifelong Learning to Empowerment: Beyond Formal Education

Science.gov (United States)

Carr, Alexis; Balasubramanian, K.; Atieno, Rosemary; Onyango, James

2018-01-01

This paper discusses the relevance of lifelong learning vis-à-vis the Sustainable Development Goals (SDGs) and stresses the need for an approach blending formal education, non-formal and informal learning. The role of Open and Distance Learning (ODL) in moving beyond formal education and the importance of integrating pedagogy, andragogy and…

Social network analysis of study environment

Directory of Open Access Journals (Sweden)

Blaženka Divjak

2010-06-01

Full Text Available Student working environment influences student learning and achievement level. In this respect social aspects of students’ formal and non-formal learning play special role in learning environment. The main research problem of this paper is to find out if students' academic performance influences their position in different students' social networks. Further, there is a need to identify other predictors of this position. In the process of problem solving we use the Social Network Analysis (SNA that is based on the data we collected from the students at the Faculty of Organization and Informatics, University of Zagreb. There are two data samples: in the basic sample N=27 and in the extended sample N=52. We collected data on social-demographic position, academic performance, learning and motivation styles, student status (full-time/part-time, attitudes towards individual and teamwork as well as informal cooperation. Afterwards five different networks (exchange of learning materials, teamwork, informal communication, basic and aggregated social network were constructed. These networks were analyzed with different metrics and the most important were betweenness, closeness and degree centrality. The main result is, firstly, that the position in a social network cannot be forecast only by academic success and, secondly, that part-time students tend to form separate groups that are poorly connected with full-time students. In general, position of a student in social networks in study environment can influence student learning as well as her/his future employability and therefore it is worthwhile to be investigated.

The Communications and Networks Collaborative Technology Alliance Publication Network: A Case Study on Graph and Simplicial Complex Analysis

Science.gov (United States)

2015-05-01

Because of this closure property on subsets, simplicial complexes are amenable to mathe - matical formalism in combinatorics, abstract algebra, and...Introduction. Oxford (United Kingdom): Oxford University Press. 7. Wasserman S, Faust K. 1994. Social Network Analysis: Methods and Applica- tions. New York (NY...Bollen J, Nelson ML, Van de Sompel H. Co-authorship networks in the digital library research community. Information Processing and Management. 2005;41

Development of Shale Gas Supply Chain Network under Market Uncertainties

Directory of Open Access Journals (Sweden)

Jorge Chebeir

2017-02-01

Full Text Available The increasing demand of energy has turned the shale gas and shale oil into one of the most promising sources of energy in the United States. In this article, a model is proposed to address the long-term planning problem of the shale gas supply chain under uncertain conditions. A two-stage stochastic programming model is proposed to describe and optimize the shale gas supply chain network. Inherent uncertainty in final products’ prices, such as natural gas and natural gas liquids (NGL, is treated through the utilization of a scenario-based method. A binomial option pricing model is utilized to approximate the stochastic process through the generation of scenario trees. The aim of the proposed model is to generate an appropriate and realistic supply chain network configuration as well as scheduling of different operations throughout the planning horizon of a shale gas development project.

The Higgs mechanism in a covariant-gauge formalism

International Nuclear Information System (INIS)

Yokoyama, Kan-ichi; Kubo, Reijiro.

1975-02-01

In a covariant-gauge formalism for gauge fields the Higgs mechanism is investigated under a spontaneous breakdown of gauge invariance. It is shown that the Goldstone bosons are in general described by a dipole-ghost field and can be consistently eliminated from the physical state-vector space by supplementary conditions. By an asymptotic condition for the relevant fields, field equations and commutators of asymptotic fields are determined. A renormalization problem and an aspect concerning gauge transformations are also discussed. (auth.)

A statistical framework for differential network analysis from microarray data

Directory of Open Access Journals (Sweden)

Datta Somnath

2010-02-01

Full Text Available Abstract Background It has been long well known that genes do not act alone; rather groups of genes act in consort during a biological process. Consequently, the expression levels of genes are dependent on each other. Experimental techniques to detect such interacting pairs of genes have been in place for quite some time. With the advent of microarray technology, newer computational techniques to detect such interaction or association between gene expressions are being proposed which lead to an association network. While most microarray analyses look for genes that are differentially expressed, it is of potentially greater significance to identify how entire association network structures change between two or more biological settings, say normal versus diseased cell types. Results We provide a recipe for conducting a differential analysis of networks constructed from microarray data under two experimental settings. At the core of our approach lies a connectivity score that represents the strength of genetic association or interaction between two genes. We use this score to propose formal statistical tests for each of following queries: (i whether the overall modular structures of the two networks are different, (ii whether the connectivity of a particular set of "interesting genes" has changed between the two networks, and (iii whether the connectivity of a given single gene has changed between the two networks. A number of examples of this score is provided. We carried out our method on two types of simulated data: Gaussian networks and networks based on differential equations. We show that, for appropriate choices of the connectivity scores and tuning parameters, our method works well on simulated data. We also analyze a real data set involving normal versus heavy mice and identify an interesting set of genes that may play key roles in obesity. Conclusions Examining changes in network structure can provide valuable information about the

Formal Model-Driven Engineering: Generating Data and Behavioural Components

Directory of Open Access Journals (Sweden)

Chen-Wei Wang

2012-12-01

Full Text Available Model-driven engineering is the automatic production of software artefacts from abstract models of structure and functionality. By targeting a specific class of system, it is possible to automate aspects of the development process, using model transformations and code generators that encode domain knowledge and implementation strategies. Using this approach, questions of correctness for a complex, software system may be answered through analysis of abstract models of lower complexity, under the assumption that the transformations and generators employed are themselves correct. This paper shows how formal techniques can be used to establish the correctness of model transformations used in the generation of software components from precise object models. The source language is based upon existing, formal techniques; the target language is the widely-used SQL notation for database programming. Correctness is established by giving comparable, relational semantics to both languages, and checking that the transformations are semantics-preserving.

A Sociability-Based Routing Scheme for Delay-Tolerant Networks

Directory of Open Access Journals (Sweden)

Fabbri Flavio

2011-01-01

Full Text Available The problem of choosing the best forwarders in Delay-Tolerant Networks (DTNs is crucial for minimizing the delay in packet delivery and for keeping the amount of generated traffic under control. In this paper, we introduce sociable routing, a novel routing strategy that selects a subset of optimal forwarders among all the nodes and relies on them for an efficient delivery. The key idea is that of assigning to each network node a time-varying scalar parameter which captures its social behavior in terms of frequency and types of encounters. This sociability concept is widely discussed and mathematically formalized. Simulation results of a DTN of vehicles in urban environment, driven by real mobility traces, and employing sociable routing, is presented. Encouraging results show that sociable routing, compared to other known protocols, achieves a good compromise in terms of delay performance and amount of generated traffic.

Network Analysis on Attitudes: A Brief Tutorial.

Science.gov (United States)

Dalege, Jonas; Borsboom, Denny; van Harreveld, Frenk; van der Maas, Han L J

2017-07-01

In this article, we provide a brief tutorial on the estimation, analysis, and simulation on attitude networks using the programming language R. We first discuss what a network is and subsequently show how one can estimate a regularized network on typical attitude data. For this, we use open-access data on the attitudes toward Barack Obama during the 2012 American presidential election. Second, we show how one can calculate standard network measures such as community structure, centrality, and connectivity on this estimated attitude network. Third, we show how one can simulate from an estimated attitude network to derive predictions from attitude networks. By this, we highlight that network theory provides a framework for both testing and developing formalized hypotheses on attitudes and related core social psychological constructs.

How Might Better Network Theories Support School Leadership Research?

Science.gov (United States)

Hadfield, Mark; Jopling, Michael

2012-01-01

This article explores how recent research in education has applied different aspects of "network" theory to the study of school leadership. Constructs from different network theories are often used because of their perceived potential to clarify two perennial issues in leadership research. The first is the relative importance of formal and…

Neural network construction via back-propagation

International Nuclear Information System (INIS)

Burwick, T.T.

1994-06-01

A method is presented that combines back-propagation with multi-layer neural network construction. Back-propagation is used not only to adjust the weights but also the signal functions. Going from one network to an equivalent one that has additional linear units, the non-linearity of these units and thus their effective presence is then introduced via back-propagation (weight-splitting). The back-propagated error causes the network to include new units in order to minimize the error function. We also show how this formalism allows to escape local minima

Formal Symplectic Groupoid of a Deformation Quantization

Science.gov (United States)

Karabegov, Alexander V.

2005-08-01

We give a self-contained algebraic description of a formal symplectic groupoid over a Poisson manifold M. To each natural star product on M we then associate a canonical formal symplectic groupoid over M. Finally, we construct a unique formal symplectic groupoid ‘with separation of variables’ over an arbitrary Kähler-Poisson manifold.

A Survey of Formal Methods for Intelligent Swarms

Science.gov (United States)

Truszkowski, Walt; Rash, James; Hinchey, Mike; Rouff, Chrustopher A.

2004-01-01

cutting edge in system correctness, and requires higher levels of assurance than other (traditional) missions that use a single or small number of spacecraft that are deterministic in nature and have near continuous communication access. One of the highest possible levels of assurance comes from the application of formal methods. Formal methods are mathematics-based tools and techniques for specifying and verifying (software and hardware) systems. They are particularly useful for specifying complex parallel systems, such as exemplified by the ANTS mission, where the entire system is difficult for a single person to fully understand, a problem that is multiplied with multiple developers. Once written, a formal specification can be used to prove properties of a system (e.g., the underlying system will go from one state to another or not into a specific state) and check for particular types of errors (e.g., race or livelock conditions). A formal specification can also be used as input to a model checker for further validation. This report gives the results of a survey of formal methods techniques for verification and validation of space missions that use swarm technology. Multiple formal methods were evaluated to determine their effectiveness in modeling and assuring the behavior of swarms of spacecraft using the ANTS mission as an example system. This report is the first result of the project to determine formal approaches that are promising for formally specifying swarm-based systems. From this survey, the most promising approaches were selected and are discussed relative to their possible application to the ANTS mission. Future work will include the application of an integrated approach, based on the selected approaches identified in this report, to the formal specification of the ANTS mission.

Artificial organic networks artificial intelligence based on carbon networks

CERN Document Server

Ponce-Espinosa, Hiram; Molina, Arturo

2014-01-01

This monograph describes the synthesis and use of biologically-inspired artificial hydrocarbon networks (AHNs) for approximation models associated with machine learning and a novel computational algorithm with which to exploit them. The reader is first introduced to various kinds of algorithms designed to deal with approximation problems and then, via some conventional ideas of organic chemistry, to the creation and characterization of artificial organic networks and AHNs in particular. The advantages of using organic networks are discussed with the rules to be followed to adapt the network to its objectives. Graph theory is used as the basis of the necessary formalism. Simulated and experimental examples of the use of fuzzy logic and genetic algorithms with organic neural networks are presented and a number of modeling problems suitable for treatment by AHNs are described: ·        approximation; ·        inference; ·        clustering; ·        control; ·        class...

multiPDEVS: A Parallel Multicomponent System Specification Formalism

Directory of Open Access Journals (Sweden)

Damien Foures

2018-01-01

Full Text Available Based on multiDEVS formalism, we introduce multiPDEVS, a parallel and nonmodular formalism for discrete event system specification. This formalism provides combined advantages of PDEVS and multiDEVS approaches, such as excellent simulation capabilities for simultaneously scheduled events and components able to influence each other using exclusively their state transitions. We next show the soundness of the formalism by giving a construction showing that any multiPDEVS model is equivalent to a PDEVS atomic model. We then present the simulation procedure associated, usually called abstract simulator. As a well-adapted formalism to express cellular automata, we finally propose to compare an implementation of multiPDEVS formalism with a more classical Cell-DEVS implementation through a fire spread application.

Towards a model-based development approach for wireless sensor-actuator network protocols

DEFF Research Database (Denmark)

Kumar S., A. Ajith; Simonsen, Kent Inge

2014-01-01

Model-Driven Software Engineering (MDSE) is a promising approach for the development of applications, and has been well adopted in the embedded applications domain in recent years. Wireless Sensor Actuator Networks consisting of resource constrained hardware and platformspecific operating system...... induced due to manual translations. With the use of formal semantics in the modeling approach, we can further ensure the correctness of the source model by means of verification. Also, with the use of network simulators and formal modeling tools, we obtain a verified and validated model to be used...

Serviceability Assessment for Cascading Failures in Water Distribution Network under Seismic Scenario

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Qing Shuang

2016-01-01

Full Text Available The stability of water service is a hot point in industrial production, public safety, and academic research. The paper establishes a service evaluation model for the water distribution network (WDN. The serviceability is measured in three aspects: (1 the functionality of structural components under disaster environment; (2 the recognition of cascading failure process; and (3 the calculation of system reliability. The node and edge failures in WDN are interrelated under seismic excitations. The cascading failure process is provided with the balance of water supply and demand. The matrix-based system reliability (MSR method is used to represent the system events and calculate the nonfailure probability. An example is used to illustrate the proposed method. The cascading failure processes with different node failures are simulated. The serviceability is analyzed. The critical node can be identified. The result shows that the aged network has a greater influence on the system service under seismic scenario. The maintenance could improve the antidisaster ability of WDN. Priority should be given to controlling the time between the initial failure and the first secondary failure, for taking postdisaster emergency measures within this time period can largely cut down the spread of cascade effect in the whole WDN.

The research on optimization of auto supply chain network robust model under macroeconomic fluctuations

International Nuclear Information System (INIS)

Guo, Chunxiang; Liu, Xiaoli; Jin, Maozhu; Lv, Zhihan

2016-01-01

Considering the uncertainty of the macroeconomic environment, the robust optimization method is studied for constructing and designing the automotive supply chain network, and based on the definition of robust solution a robust optimization model is built for integrated supply chain network design that consists of supplier selection problem and facility location–distribution problem. The tabu search algorithm is proposed for supply chain node configuration, analyzing the influence of the level of uncertainty on robust results, and by comparing the performance of supply chain network design through the stochastic programming model and robustness optimize model, on this basis, determining the rational layout of supply chain network under macroeconomic fluctuations. At last the contrastive test result validates that the performance of tabu search algorithm is outstanding on convergence and computational time. Meanwhile it is indicated that the robust optimization model can reduce investment risks effectively when it is applied to supply chain network design.

Electrohydrodynamic fibrillation governed enhanced thermal transport in dielectric colloids under a field stimulus.

Science.gov (United States)

Dhar, Purbarun; Maganti, Lakshmi Sirisha; Harikrishnan, A R

2018-05-30

Electrorheological (ER) fluids are known to exhibit enhanced viscous effects under an electric field stimulus. The present article reports the hitherto unreported phenomenon of greatly enhanced thermal conductivity in such electro-active colloidal dispersions in the presence of an externally applied electric field. Typical ER fluids are synthesized employing dielectric fluids and nanoparticles and experiments are performed employing an in-house designed setup. Greatly augmented thermal conductivity under a field's influence was observed. Enhanced thermal conduction along the fibril structures under the field effect is theorized as the crux of the mechanism. The formation of fibril structures has also been experimentally verified employing microscopy. Based on classical models for ER fluids, a mathematical formalism has been developed to predict the propensity of chain formation and statistically feasible chain dynamics at given Mason numbers. Further, a thermal resistance network model is employed to computationally predict the enhanced thermal conduction across the fibrillary colloid microstructure. Good agreement between the mathematical model and the experimental observations is achieved. The domineering role of thermal conductivity over relative permittivity has been shown by proposing a modified Hashin-Shtrikman (HS) formalism. The findings have implications towards better physical understanding and design of ER fluids from both 'smart' viscoelastic as well as thermally active materials points of view.

Practical Formal Verification of MPI and Thread Programs

Science.gov (United States)

Gopalakrishnan, Ganesh; Kirby, Robert M.

Large-scale simulation codes in science and engineering are written using the Message Passing Interface (MPI). Shared memory threads are widely used directly, or to implement higher level programming abstractions. Traditional debugging methods for MPI or thread programs are incapable of providing useful formal guarantees about coverage. They get bogged down in the sheer number of interleavings (schedules), often missing shallow bugs. In this tutorial we will introduce two practical formal verification tools: ISP (for MPI C programs) and Inspect (for Pthread C programs). Unlike other formal verification tools, ISP and Inspect run directly on user source codes (much like a debugger). They pursue only the relevant set of process interleavings, using our own customized Dynamic Partial Order Reduction algorithms. For a given test harness, DPOR allows these tools to guarantee the absence of deadlocks, instrumented MPI object leaks and communication races (using ISP), and shared memory races (using Inspect). ISP and Inspect have been used to verify large pieces of code: in excess of 10,000 lines of MPI/C for ISP in under 5 seconds, and about 5,000 lines of Pthread/C code in a few hours (and much faster with the use of a cluster or by exploiting special cases such as symmetry) for Inspect. We will also demonstrate the Microsoft Visual Studio and Eclipse Parallel Tools Platform integrations of ISP (these will be available on the LiveCD).

Decision making under uncertainty: An investigation into the application of formal decision-making methods to safety issue decisions

International Nuclear Information System (INIS)

Bohn, M.P.

1992-12-01

As part of the NRC-sponsored program to study the implications of Generic Issue 57, ''Effects of Fire Protection System Actuation on Safety-Related Equipment,'' a subtask was performed to evaluate the applicability of formal decision analysis methods to generic issues cost/benefit-type decisions and to apply these methods to the GI-57 results. In this report, the numerical results obtained from the analysis of three plants (two PWRs and one BWR) as developed in the technical resolution program for GI-57 were studied. For each plant, these results included a calculation of the person-REM averted due to various accident scenarios and various proposed modifications to mitigate the accident scenarios identified. These results were recomputed to break out the benefit in terms of contributions due to random event scenarios, fire event scenarios, and seismic event scenarios. Furthermore, the benefits associated with risk (in terms of person-REM) averted from earthquakes at three different seismic ground motion levels were separately considered. Given this data, formal decision methodologies involving decision trees, value functions, and utility functions were applied to this basic data. It is shown that the formal decision methodology can be applied at several different levels. Examples are given in which the decision between several retrofits is changed from that resulting from a simple cost/benefit-ratio criterion by virtue of the decision-makinger's expressed (and assumed) preferences

Bridging In-school and Out-of-school Learning: Formal, Non-Formal, and Informal Education

Science.gov (United States)

Eshach, Haim

2007-04-01

The present paper thoroughly examines how one can effectively bridge in-school and out-of-school learning. The first part discusses the difficulty in defining out-of-school learning. It proposes to distinguish three types of learning: formal, informal, and non-formal. The second part raises the question of whether out-of-school learning should be dealt with in the in-school system, in view of the fact that we experience informal learning anyway as well as considering the disadvantages and difficulties teachers are confronted with when planning and carrying out scientific fieldtrips. The voices of the teachers, the students, and the non-formal institution staff are heard to provide insights into the problem. The third part discusses the cognitive and affective aspects of non-formal learning. The fourth part presents some models explaining scientific fieldtrip learning and based on those models, suggests a novel explanation. The fifth part offers some recommendations of how to bridge in and out-of-school learning. The paper closes with some practical ideas as to how one can bring the theory described in the paper into practice. It is hoped that this paper will provide educators with an insight so that they will be able to fully exploit the great potential that scientific field trips may offer.

Toward a formal ontology for narrative

Directory of Open Access Journals (Sweden)

Ciotti, Fabio

2016-03-01

Full Text Available In this paper the rationale and the first draft of a formal ontology for modeling narrative texts are presented. Building on the semiotic and structuralist narratology, and on the work carried out in the late 1980s by Giuseppe Gigliozzi in Italy, the focus of my research are the concepts of character and of narrative world/space. This formal model is expressed in the OWL 2 ontology language. The main reason to adopt a formal modeling approach is that I consider the purely probabilistic-quantitative methods (now widespread in digital literary studies inadequate. An ontology, on one hand provides a tool for the analysis of strictly literary texts. On the other hand (though beyond the scope of the present work, its formalization can also represent a significant contribution towards grounding the application of storytelling methods outside of scholarly contexts.

Industrial Practice in Formal Methods : A Review

DEFF Research Database (Denmark)

Bicarregui, Juan C.; Fitzgerald, John; Larsen, Peter Gorm

2009-01-01

We examine the the industrial application of formal methods using data gathered in a review of 62 projects taking place over the last 25 years. The review suggests that formal methods are being applied in a wide range of application domains, with increasingly strong tool support. Significant chal...... challenges remain in providing usable tools that can be integrated into established development processes; in education and training; in taking formal methods from first use to second use, and in gathering and evidence to support informed selection of methods and tools.......We examine the the industrial application of formal methods using data gathered in a review of 62 projects taking place over the last 25 years. The review suggests that formal methods are being applied in a wide range of application domains, with increasingly strong tool support. Significant...

Formal verification - Robust and efficient code: Introduction to Formal Verification

CERN Multimedia

CERN. Geneva

2016-01-01

In general, FV means "proving that certain properties hold for a given system using formal mathematics". This definition can certainly feel daunting, however, as we will learn, we can reap benefits from the paradigm without digging too deep into ...

Formalization of the Resolution Calculus for First-Order Logic

DEFF Research Database (Denmark)

Schlichtkrull, Anders

2016-01-01

A formalization in Isabelle/HOL of the resolution calculus for first-order logic is presented. Its soundness and completeness are formally proven using the substitution lemma, semantic trees, Herbrand’s theorem, and the lifting lemma. In contrast to previous formalizations of resolution, it consi......A formalization in Isabelle/HOL of the resolution calculus for first-order logic is presented. Its soundness and completeness are formally proven using the substitution lemma, semantic trees, Herbrand’s theorem, and the lifting lemma. In contrast to previous formalizations of resolution...

Core regulatory network motif underlies the ocellar complex patterning in Drosophila melanogaster

Science.gov (United States)

Aguilar-Hidalgo, D.; Lemos, M. C.; Córdoba, A.

2015-03-01

During organogenesis, developmental programs governed by Gene Regulatory Networks (GRN) define the functionality, size and shape of the different constituents of living organisms. Robustness, thus, is an essential characteristic that GRNs need to fulfill in order to maintain viability and reproducibility in a species. In the present work we analyze the robustness of the patterning for the ocellar complex formation in Drosophila melanogaster fly. We have systematically pruned the GRN that drives the development of this visual system to obtain the minimum pathway able to satisfy this pattern. We found that the mechanism underlying the patterning obeys to the dynamics of a 3-nodes network motif with a double negative feedback loop fed by a morphogenetic gradient that triggers the inhibition in a French flag problem fashion. A Boolean modeling of the GRN confirms robustness in the patterning mechanism showing the same result for different network complexity levels. Interestingly, the network provides a steady state solution in the interocellar part of the patterning and an oscillatory regime in the ocelli. This theoretical result predicts that the ocellar pattern may underlie oscillatory dynamics in its genetic regulation.

Formalizing Knowledge in Multi-Scale Agent-Based Simulations.

Science.gov (United States)

Somogyi, Endre; Sluka, James P; Glazier, James A

2016-10-01

Multi-scale, agent-based simulations of cellular and tissue biology are increasingly common. These simulations combine and integrate a range of components from different domains. Simulations continuously create, destroy and reorganize constituent elements causing their interactions to dynamically change. For example, the multi-cellular tissue development process coordinates molecular, cellular and tissue scale objects with biochemical, biomechanical, spatial and behavioral processes to form a dynamic network. Different domain specific languages can describe these components in isolation, but cannot describe their interactions. No current programming language is designed to represent in human readable and reusable form the domain specific knowledge contained in these components and interactions. We present a new hybrid programming language paradigm that naturally expresses the complex multi-scale objects and dynamic interactions in a unified way and allows domain knowledge to be captured, searched, formalized, extracted and reused.

Merging social networking environments and formal learning environments to support and facilitate interprofessional instruction.

Science.gov (United States)

King, Sharla; Greidanus, Elaine; Carbonaro, Michael; Drummond, Jane; Patterson, Steven

2009-04-28

This study describes the redesign of an interprofessional team development course for health science students. A theoretical model is hypothesized as a framework for the redesign process, consisting of two themes: 1) the increasing trend among post-secondary students to participate in social networking (e.g., Facebook, Second Life) and 2) the need for healthcare educators to provide interprofessional training that results in effective communities of practice and better patient care. The redesign focused on increasing the relevance of the course through the integration of custom-designed technology to facilitate social networking during their interprofessional education. Results suggest that students in an educationally structured social networking environment can be guided to join learning communities quickly and access course materials. More research and implementation work is required to effectively develop interprofessional health sciences communities in a combined face-to-face and on-line social networking context.

First formal ITER negotiations make excellent progress

International Nuclear Information System (INIS)

Barnard, P.

2001-01-01

November 8 and 9 2001 marked the historic beginning of formal negotiations meetings on the ITER project. Delegations from Canada, the European Union, Japan and the Russian Federation met in Toronto, Canada, for the first in a series of Negotiations that is expected to lead, by the end of 2002, to an agreement on the joint implementation of ITER. This agreement will govern, under international law, the construction, operation and decommissioning of ITER. The Negotiations concluded by issuing a joint news release, reflecting a commitment to share the progress reports on the efforts to implement ITER

A Formal Calculus for Categories

DEFF Research Database (Denmark)

Cáccamo, Mario José

This dissertation studies the logic underlying category theory. In particular we present a formal calculus for reasoning about universal properties. The aim is to systematise judgements about functoriality and naturality central to categorical reasoning. The calculus is based on a language which...... extends the typed lambda calculus with new binders to represent universal constructions. The types of the languages are interpreted as locally small categories and the expressions represent functors. The logic supports a syntactic treatment of universality and duality. Contravariance requires a definition...... of universality generous enough to deal with functors of mixed variance. Ends generalise limits to cover these kinds of functors and moreover provide the basis for a very convenient algebraic manipulation of expressions. The equational theory of the lambda calculus is extended with new rules for the definitions...

A multi-region multi-energy formalism for the Feynman-alpha formulas

International Nuclear Information System (INIS)

Malinovitch, T.; Dubi, C.

2015-01-01

Highlights: • A formalism of N regions and M groups for the Feynman-α method is introduced. • Using a space-energy cell notation the expressions are simplified significantly. • A simple way to incorporate the detectors in the system is used. • The results have been verified by a Monte Carlo simulation in a two-region case. - Abstract: The stochastic transport equation, describing the dynamics in time of the neutron population in a nuclear system, is used to gain expressions for the higher moments of the neutron population in a sub-critical system. Such expressions are the bone structure of the so called Feynman-α method to analyze noise experiments, aimed to determine the reactivity of sub-critical systems. In the present study, a general formalism for the stochastic transport equation in an N regions system, under the M energy groups approximation will be introduced. In particular, expressions for the Feynman variance to mean (or the Feynman-Y function) under the above mentioned restriction will be sought by using the steady state mode of the solution

Designing container shipping network under changing demand and freight rates

Directory of Open Access Journals (Sweden)

C. Chen

2010-03-01

Full Text Available This paper focuses on the optimization of container shipping network and its operations under changing cargo demand and freight rates. The problem is formulated as a mixed integer non-linear programming problem (MINP with an objective of maximizing the average unit ship-slot profit at three stages using analytical methodology. The issues such as empty container repositioning, ship-slot allocating, ship sizing, and container configuration are simultaneously considered based on a series of the matrices of demand for a year. To solve the model, a bi-level genetic algorithm based method is proposed. Finally, numerical experiments are provided to illustrate the validity of the proposed model and algorithms. The obtained results show that the suggested model can provide a more realistic solution to the issues on the basis of changing demand and freight rates and arrange a more effective approach to the optimization of container shipping network structures and operations than does the model based on the average demand.

Converging models of schizophrenia - Network alterations of prefrontal cortex underlying cognitive impairments

Science.gov (United States)

Sakurai, Takeshi; Gamo, Nao J; Hikida, Takatoshi; Kim, Sun-Hong; Murai, Toshiya; Tomoda, Toshifumi; Sawa, Akira

2015-01-01

The prefrontal cortex (PFC) and its connections with other brain areas are crucial for cognitive function. Cognitive impairments are one of the core symptoms associated with schizophrenia, and manifest even before the onset of the disorder. Altered neural networks involving PFC contribute to cognitive impairments in schizophrenia. Both genetic and environmental risk factors affect the development of the local circuitry within PFC as well as development of broader brain networks, and make the system vulnerable to further insults during adolescence, leading to the onset of the disorder in young adulthood. Since spared cognitive functions correlate with functional outcome and prognosis, a better understanding of the mechanisms underlying cognitive impairments will have important implications for novel therapeutics for schizophrenia focusing on cognitive functions. Multidisciplinary approaches, from basic neuroscience to clinical studies, are required to link molecules, circuitry, networks, and behavioral phenotypes. Close interactions among such fields by sharing a common language on connectomes, behavioral readouts, and other concepts are crucial for this goal. PMID:26408506

Network interactions underlying mirror feedback in stroke: A dynamic causal modeling study

Directory of Open Access Journals (Sweden)

Soha Saleh

2017-01-01

Full Text Available Mirror visual feedback (MVF is potentially a powerful tool to facilitate recovery of disordered movement and stimulate activation of under-active brain areas due to stroke. The neural mechanisms underlying MVF have therefore been a focus of recent inquiry. Although it is known that sensorimotor areas can be activated via mirror feedback, the network interactions driving this effect remain unknown. The aim of the current study was to fill this gap by using dynamic causal modeling to test the interactions between regions in the frontal and parietal lobes that may be important for modulating the activation of the ipsilesional motor cortex during mirror visual feedback of unaffected hand movement in stroke patients. Our intent was to distinguish between two theoretical neural mechanisms that might mediate ipsilateral activation in response to mirror-feedback: transfer of information between bilateral motor cortices versus recruitment of regions comprising an action observation network which in turn modulate the motor cortex. In an event-related fMRI design, fourteen chronic stroke subjects performed goal-directed finger flexion movements with their unaffected hand while observing real-time visual feedback of the corresponding (veridical or opposite (mirror hand in virtual reality. Among 30 plausible network models that were tested, the winning model revealed significant mirror feedback-based modulation of the ipsilesional motor cortex arising from the contralesional parietal cortex, in a region along the rostral extent of the intraparietal sulcus. No winning model was identified for the veridical feedback condition. We discuss our findings in the context of supporting the latter hypothesis, that mirror feedback-based activation of motor cortex may be attributed to engagement of a contralateral (contralesional action observation network. These findings may have important implications for identifying putative cortical areas, which may be targeted with

Institutions of Non-Formal Education of Astronomy in Brazil and their Distribution on the National Territory

Science.gov (United States)

Marques, Joana Brás Varanda; de Freitas, Denise

2015-12-01

This article presents the results of a survey of Brazilian institutions of non-formal education and popularization of Astronomy. The non-formal sector of education and scientific dissemination are areas in expansion throughout the world and also in Brazil. Astronomy is a privileged science due to the network of existing institutions, but there is little research on this issue and the information about institutions are neither integrated nor updated. In response, this paper presents the results of a systematic survey of planetariums, observatories, museums and associations dedicated to education in astronomy in Brazil. The survey was executed by compiling and updating of existing partial listings on equipment and institutions. It can be concluded that in Brazil there are nearly 500 institutions dedicated to this area but these institutions are distributed unevenly across the country.

Formalizing Evaluation in Music Information Retrieval

DEFF Research Database (Denmark)

Sturm, Bob L.

2013-01-01

We develop a formalism to disambiguate the evaluation of music information retrieval systems. We define a ``system,'' what it means to ``analyze'' one, and make clear the aims, parts, design, execution, interpretation, and assumptions of its ``evaluation.'' We apply this formalism to discuss...

A computational formalization for partial evaluation

DEFF Research Database (Denmark)

Hatcliff, John; Danvy, Olivier

1997-01-01

We formalize a partial evaluator for Eugenio Moggi's computational metalanguage. This formalization gives an evaluation-order independent view of binding-time analysis and program specialization, including a proper treatment of call unfolding. It also enables us to express the essence of `control...

Informal work and formal plans

DEFF Research Database (Denmark)

Dalsted, Rikke Juul; Hølge-Hazelton, Bibi; Kousgaard, Marius Brostrøm

2012-01-01

INTRODUCTION: Formal pathways models outline that patients should receive information in order to experience a coherent journey but do not describe an active role for patients or their relatives. The aim of this is paper is to articulate and discuss the active role of patients during their cancer...... trajectories. METHODS AND THEORY: An in-depth case study of patient trajectories at a Danish hospital and surrounding municipality using individual interviews with patients. Theory about trajectory and work by Strauss was included. RESULTS: Patients continuously took initiatives to organize their treatment....... The patients' requests were not sufficiently supported in the professional organisation of work or formal planning. Patients' insertion and use of information in their trajectories challenged professional views and working processes. And the design of the formal pathway models limits the patients' active...

Formalisms for reuse and systems integration

CERN Document Server

Rubin, Stuart

2015-01-01

Reuse and integration are defined as synergistic concepts, where reuse addresses how to minimize redundancy in the creation of components; while, integration focuses on component composition. Integration supports reuse and vice versa. These related concepts support the design of software and systems for maximizing performance while minimizing cost. Knowledge, like data, is subject to reuse; and, each can be interpreted as the other. This means that inherent complexity, a measure of the potential utility of a system, is directly proportional to the extent to which it maximizes reuse and integration. Formal methods can provide an appropriate context for the rigorous handling of these synergistic concepts. Furthermore, formal languages allow for non ambiguous model specification; and, formal verification techniques provide support for insuring the validity of reuse and integration mechanisms.   This edited book includes 12 high quality research papers written by experts in formal aspects of reuse and integratio...

Formal Methods in Air Traffic Management: The Case of Unmanned Aircraft Systems

Science.gov (United States)

Munoz, Cesar A.

2015-01-01

As the technological and operational capabilities of unmanned aircraft systems (UAS) continue to grow, so too does the need to introduce these systems into civil airspace. Unmanned Aircraft Systems Integration in the National Airspace System is a NASA research project that addresses the integration of civil UAS into non-segregated airspace operations. One of the major challenges of this integration is the lack of an onboard pilot to comply with the legal requirement that pilots see and avoid other aircraft. The need to provide an equivalent to this requirement for UAS has motivated the development of a detect and avoid (DAA) capability to provide the appropriate situational awareness and maneuver guidance in avoiding and remaining well clear of traffic aircraft. Formal methods has played a fundamental role in the development of this capability. This talk reports on the formal methods work conducted under NASA's Safe Autonomous System Operations project in support of the development of DAA for UAS. This work includes specification of low-level and high-level functional requirements, formal verification of algorithms, and rigorous validation of software implementations. The talk also discusses technical challenges in formal methods research in the context of the development and safety analysis of advanced air traffic management concepts.

Model-Based Design and Formal Verification Processes for Automated Waterway System Operations

Directory of Open Access Journals (Sweden)

Leonard Petnga

2016-06-01

Full Text Available Waterway and canal systems are particularly cost effective in the transport of bulk and containerized goods to support global trade. Yet, despite these benefits, they are among the most under-appreciated forms of transportation engineering systems. Looking ahead, the long-term view is not rosy. Failures, delays, incidents and accidents in aging waterway systems are doing little to attract the technical and economic assistance required for modernization and sustainability. In a step toward overcoming these challenges, this paper argues that programs for waterway and canal modernization and sustainability can benefit significantly from system thinking, supported by systems engineering techniques. We propose a multi-level multi-stage methodology for the model-based design, simulation and formal verification of automated waterway system operations. At the front-end of development, semi-formal modeling techniques are employed for the representation of project goals and scenarios, requirements and high-level models of behavior and structure. To assure the accuracy of engineering predictions and the correctness of operations, formal modeling techniques are used for the performance assessment and the formal verification of the correctness of functionality. The essential features of this methodology are highlighted in a case study examination of ship and lock-system behaviors in a two-stage lock system.

Dynamic Group Diffie-Hellman Key Exchange under standard assumptions

International Nuclear Information System (INIS)

Bresson, Emmanuel; Chevassut, Olivier; Pointcheval, David

2002-01-01

Authenticated Diffie-Hellman key exchange allows two principals communicating over a public network, and each holding public-private keys, to agree on a shared secret value. In this paper we study the natural extension of this cryptographic problem to a group of principals. We begin from existing formal security models and refine them to incorporate major missing details (e.g., strong-corruption and concurrent sessions). Within this model we define the execution of a protocol for authenticated dynamic group Diffie-Hellman and show that it is provably secure under the decisional Diffie-Hellman assumption. Our security result holds in the standard model and thus provides better security guarantees than previously published results in the random oracle model

On Central Branch/Reinsurance Risk Networks: Exact Results and Heuristics

Directory of Open Access Journals (Sweden)

Florin Avram

2018-04-01

Full Text Available Modeling the interactions between a reinsurer and several insurers, or between a central management branch (CB and several subsidiary business branches, or between a coalition and its members, are fascinating problems, which suggest many interesting questions. Beyond two dimensions, one cannot expect exact answers. Occasionally, reductions to one dimension or heuristic simplifications yield explicit approximations, which may be useful for getting qualitative insights. In this paper, we study two such problems: the ruin problem for a two-dimensional CB network under a new mathematical model, and the problem of valuation of two-dimensional CB networks by optimal dividends. A common thread between these two problems is that the one dimensional reduction exploits the concept of invariant cones. Perhaps the most important contribution of the paper is the questions it raises; for that reason, we have found it useful to complement the particular examples solved by providing one possible formalization of the concept of a multi-dimensional risk network, which seems to us an appropriate umbrella for the kind of questions raised here.

Formal Engineering Hybrid Systems: Semantic Underpinnings

NARCIS (Netherlands)

Bujorianu, M.C.; Bujorianu, L.M.

2008-01-01

In this work we investigate some issues in applying formal methods to hybrid system development and develop a categorical framework. We study the themes of stochastic reasoning, heterogeneous formal specification and retrenchment. Hybrid systems raise a rich pallets of aspects that need to be

Formal Analysis Of Use Case Diagrams

Directory of Open Access Journals (Sweden)

Radosław Klimek

2010-01-01

Full Text Available Use case diagrams play an important role in modeling with UML. Careful modeling is crucialin obtaining a correct and efficient system architecture. The paper refers to the formalanalysis of the use case diagrams. A formal model of use cases is proposed and its constructionfor typical relationships between use cases is described. Two methods of formal analysis andverification are presented. The first one based on a states’ exploration represents a modelchecking approach. The second one refers to the symbolic reasoning using formal methodsof temporal logic. Simple but representative example of the use case scenario verification isdiscussed.

L.I.M.E. A recommendation model for informal and formal learning, engaged

Directory of Open Access Journals (Sweden)

Daniel Burgos

2013-06-01

Full Text Available In current eLearning models and implementations (e.g. Learning Management Systems-LMS there is a lack of engagement between formal and informal activities. Furthermore, the online methodology focuses on a standard set of units of learning and learning objects, along with pre-defined tests, and collateral resources like, i.e. discussion fora and message wall. They miss the huge potential of learning via the interlacement of social networks, LMS and external sources. Thanks to user behaviour, user interaction, and personalised counselling by a tutor, learning performance can be improved. We design and develop an adaptation eLearning model for restricted social networks, which supports this approach. In addition, we build an eLearning module that implements this conceptual model in a real application case, and present the preliminary analysis and positive results.

Maximum-entropy networks pattern detection, network reconstruction and graph combinatorics

CERN Document Server

Squartini, Tiziano

2017-01-01

This book is an introduction to maximum-entropy models of random graphs with given topological properties and their applications. Its original contribution is the reformulation of many seemingly different problems in the study of both real networks and graph theory within the unified framework of maximum entropy. Particular emphasis is put on the detection of structural patterns in real networks, on the reconstruction of the properties of networks from partial information, and on the enumeration and sampling of graphs with given properties.  After a first introductory chapter explaining the motivation, focus, aim and message of the book, chapter 2 introduces the formal construction of maximum-entropy ensembles of graphs with local topological constraints. Chapter 3 focuses on the problem of pattern detection in real networks and provides a powerful way to disentangle nontrivial higher-order structural features from those that can be traced back to simpler local constraints. Chapter 4 focuses on the problem o...

Entrepreneurial networking differences: An ethnic in-group and out-group analysis

Directory of Open Access Journals (Sweden)

Boris Urban

2011-04-01

Research purpose: The research question of this study has focused on what we can learn about entrepreneurial networking, considering that there is an under-explored and unarticulated set of networking principles and practices which have not been previously analysed in terms of a multiethnic country context. Motivation for the study: Often the lack of network use is reported as a feature of entrepreneurs, who have less opportunity to utilise formal social capital features. Social networks provided by extended family, community-based or organisational relationships are often theorised to supplement the effects of education, experience and financial capital. Research design, approach and method: Based on hypothesised differences in networking ties, network assistance and support relationships, a survey was used to collect data on quantitative measures. Descriptive statistics were calculated and differential tests were conducted to test the hypotheses. Main findings: Results indicate that entrepreneurial networking is largely independent on group composition. Generally at least some aspects of networking are generic and as a consequence, a more integrated view of networking can be adopted. Practical/managerial implications: The practical value of the present study points to several areas of interest to entrepreneurs, policy makers and educators, through demonstrating the multifaceted nature of entrepreneurial networks for different groups and their explanatory potential in understanding networking. Contribution/value-add: Despite the importance of entrepreneurial networking, little empirical or theoretical research has examined the dynamics of networking in a developing country context such as South Africa, which has lower than expected total entrepreneurship activity.

Formal methods in software development: A road less travelled

Directory of Open Access Journals (Sweden)

John A van der Poll

2010-08-01

Full Text Available An integration of traditional verification techniques and formal specifications in software engineering is presented. Advocates of such techniques claim that mathematical formalisms allow them to produce quality, verifiably correct, or at least highly dependable software and that the testing and maintenance phases are shortened. Critics on the other hand maintain that software formalisms are hard to master, tedious to use and not well suited for the fast turnaround times demanded by industry. In this paper some popular formalisms and the advantages of using these during the early phases of the software development life cycle are presented. Employing the Floyd-Hoare verification principles during the formal specification phase facilitates reasoning about the properties of a specification. Some observations that may help to alleviate the formal-methods controversy are established and a number of formal methods successes is presented. Possible conditions for an increased acceptance of formalisms in oftware development are discussed.

Statistical Survey of Non-Formal Education

Directory of Open Access Journals (Sweden)

Ondřej Nývlt

2012-12-01

Full Text Available focused on a programme within a regular education system. Labour market flexibility and new requirements on employees create a new domain of education called non-formal education. Is there a reliable statistical source with a good methodological definition for the Czech Republic? Labour Force Survey (LFS has been the basic statistical source for time comparison of non-formal education for the last ten years. Furthermore, a special Adult Education Survey (AES in 2011 was focused on individual components of non-formal education in a detailed way. In general, the goal of the EU is to use data from both internationally comparable surveys for analyses of the particular fields of lifelong learning in the way, that annual LFS data could be enlarged by detailed information from AES in five years periods. This article describes reliability of statistical data aboutnon-formal education. This analysis is usually connected with sampling and non-sampling errors.

Securing ad hoc wireless sensor networks under Byzantine attacks by implementing non-cryptographic method

Directory of Open Access Journals (Sweden)

Shabir Ahmad Sofi

2017-05-01

Full Text Available Ad Hoc wireless sensor network (WSN is a collection of nodes that do not need to rely on predefined infrastructure to keep the network connected. The level of security and performance are always somehow related to each other, therefore due to limited resources in WSN, cryptographic methods for securing the network against attacks is not feasible. Byzantine attacks disrupt the communication between nodes in the network without regard to its own resource consumption. This paper discusses the performance of cluster based WSN comparing LEACH with Advanced node based clusters under byzantine attacks. This paper also proposes an algorithm for detection and isolation of the compromised nodes to mitigate the attacks by non-cryptographic means. The throughput increases after using the algorithm for isolation of the malicious nodes, 33% in case of Gray Hole attack and 62% in case of Black Hole attack.

Managing a network vulnerability assessment

CERN Document Server

Peltier, Thomas R; Blackley, John A

2003-01-01

Managing a Network Vulnerability Assessment provides a formal framework for finding and eliminating network security threats, ensuring that no vulnerabilities are overlooked. This thorough overview focuses on the steps necessary to successfully manage an assessment, including the development of a scope statement, the understanding and proper use of assessment methodology, the creation of an expert assessment team, and the production of a valuable response report. The book also details what commercial, freeware, and shareware tools are available, how they work, and how to use them.

Emergence of amplitude death scenario in a network of oscillators under repulsive delay interaction

Energy Technology Data Exchange (ETDEWEB)

Bera, Bidesh K., E-mail: bideshbera18@gmail.com [Physics and Applied Mathematics Unit, Indian Statistical Institute, Kolkata 700108 (India); Hens, Chittaranjan, E-mail: chittaranjanhens@gmail.com [Department of Mathematics, Bar-Ilan University, Ramat Gan 52900 (Israel); Ghosh, Dibakar, E-mail: dibakar@isical.ac.in [Physics and Applied Mathematics Unit, Indian Statistical Institute, Kolkata 700108 (India)

2016-07-15

Highlights: • Amplitude death is observed using repulsive mean coupling. • Analytical conditions for amplitude death are derived. • Effect of asymmetry time delay coupling for death is discussed. - Abstract: We report the existence of amplitude death in a network of identical oscillators under repulsive mean coupling. Amplitude death appears in a globally coupled network of identical oscillators with instantaneous repulsive mean coupling only when the number of oscillators is more than two. We further investigate that, amplitude death may emerge even in two coupled oscillators as well as network of oscillators if we introduce delay time in the repulsive mean coupling. We have analytically derived the region of amplitude death island and find out how strength of delay controls the death regime in two coupled or a large network of coupled oscillators. We have verified our results on network of delayed Mackey–Glass systems where parameters are set in hyperchaotic regime. We have also tested our coupling approach in two paradigmatic limit cycle oscillators: Stuart–Landau and Van der Pol oscillators.

Emergence of amplitude death scenario in a network of oscillators under repulsive delay interaction

International Nuclear Information System (INIS)

Bera, Bidesh K.; Hens, Chittaranjan; Ghosh, Dibakar

2016-01-01

Highlights: • Amplitude death is observed using repulsive mean coupling. • Analytical conditions for amplitude death are derived. • Effect of asymmetry time delay coupling for death is discussed. - Abstract: We report the existence of amplitude death in a network of identical oscillators under repulsive mean coupling. Amplitude death appears in a globally coupled network of identical oscillators with instantaneous repulsive mean coupling only when the number of oscillators is more than two. We further investigate that, amplitude death may emerge even in two coupled oscillators as well as network of oscillators if we introduce delay time in the repulsive mean coupling. We have analytically derived the region of amplitude death island and find out how strength of delay controls the death regime in two coupled or a large network of coupled oscillators. We have verified our results on network of delayed Mackey–Glass systems where parameters are set in hyperchaotic regime. We have also tested our coupling approach in two paradigmatic limit cycle oscillators: Stuart–Landau and Van der Pol oscillators.

Networks in social policy problems

CERN Document Server

Scotti, marco

2012-01-01

Network science is the key to managing social communities, designing the structure of efficient organizations and planning for sustainable development. This book applies network science to contemporary social policy problems. In the first part, tools of diffusion and team design are deployed to challenges in adoption of ideas and the management of creativity. Ideas, unlike information, are generated and adopted in networks of personal ties. Chapters in the second part tackle problems of power and malfeasance in political and business organizations, where mechanisms in accessing and controlling informal networks often outweigh formal processes. The third part uses ideas from biology and physics to understand global economic and financial crises, ecological depletion and challenges to energy security. Ideal for researchers and policy makers involved in social network analysis, business strategy and economic policy, it deals with issues ranging from what makes public advisories effective to how networks influenc...

Formalization of Many-Valued Logics

DEFF Research Database (Denmark)

Villadsen, Jørgen; Schlichtkrull, Anders

2017-01-01

Partiality is a key challenge for computational approaches to artificial intelligence in general and natural language in particular. Various extensions of classical two-valued logic to many-valued logics have been investigated in order to meet this challenge. We use the proof assistant Isabelle...... to formalize the syntax and semantics of many-valued logics with determinate as well as indeterminate truth values. The formalization allows for a concise presentation and makes automated verification possible....

Helicity formalism and spin effects

International Nuclear Information System (INIS)

Anselmino, M.; Caruso, F.; Piovano, U.

1990-01-01

The helicity formalism and the technique to compute amplitudes for interaction processes involving leptons, quarks, photons and gluons are reviewed. Explicit calculations and examples of exploitation of symmetry properties are shown. The formalism is then applied to the discussion of several hadronic processes and spin effects: the experimental data, when related to the properties of the elementary constituent interactions, show many not understood features. Also the nucleon spin problem is briefly reviewed. (author)

Silicon nanophotonics for scalable quantum coherent feedback networks

International Nuclear Information System (INIS)

Sarovar, Mohan; Brif, Constantin; Soh, Daniel B.S.; Cox, Jonathan; DeRose, Christopher T.; Camacho, Ryan; Davids, Paul

2016-01-01

The emergence of coherent quantum feedback control (CQFC) as a new paradigm for precise manipulation of dynamics of complex quantum systems has led to the development of efficient theoretical modeling and simulation tools and opened avenues for new practical implementations. This work explores the applicability of the integrated silicon photonics platform for implementing scalable CQFC networks. If proven successful, on-chip implementations of these networks would provide scalable and efficient nanophotonic components for autonomous quantum information processing devices and ultra-low-power optical processing systems at telecommunications wavelengths. We analyze the strengths of the silicon photonics platform for CQFC applications and identify the key challenges to both the theoretical formalism and experimental implementations. In particular, we determine specific extensions to the theoretical CQFC framework (which was originally developed with bulk-optics implementations in mind), required to make it fully applicable to modeling of linear and nonlinear integrated optics networks. We also report the results of a preliminary experiment that studied the performance of an in situ controllable silicon nanophotonic network of two coupled cavities and analyze the properties of this device using the CQFC formalism. (orig.)

Silicon nanophotonics for scalable quantum coherent feedback networks

Energy Technology Data Exchange (ETDEWEB)

Sarovar, Mohan; Brif, Constantin [Sandia National Laboratories, Livermore, CA (United States); Soh, Daniel B.S. [Sandia National Laboratories, Livermore, CA (United States); Stanford University, Edward L. Ginzton Laboratory, Stanford, CA (United States); Cox, Jonathan; DeRose, Christopher T.; Camacho, Ryan; Davids, Paul [Sandia National Laboratories, Albuquerque, NM (United States)

2016-12-15

The emergence of coherent quantum feedback control (CQFC) as a new paradigm for precise manipulation of dynamics of complex quantum systems has led to the development of efficient theoretical modeling and simulation tools and opened avenues for new practical implementations. This work explores the applicability of the integrated silicon photonics platform for implementing scalable CQFC networks. If proven successful, on-chip implementations of these networks would provide scalable and efficient nanophotonic components for autonomous quantum information processing devices and ultra-low-power optical processing systems at telecommunications wavelengths. We analyze the strengths of the silicon photonics platform for CQFC applications and identify the key challenges to both the theoretical formalism and experimental implementations. In particular, we determine specific extensions to the theoretical CQFC framework (which was originally developed with bulk-optics implementations in mind), required to make it fully applicable to modeling of linear and nonlinear integrated optics networks. We also report the results of a preliminary experiment that studied the performance of an in situ controllable silicon nanophotonic network of two coupled cavities and analyze the properties of this device using the CQFC formalism. (orig.)

COEL: A Cloud-based Reaction Network Simulator

Directory of Open Access Journals (Sweden)

Peter eBanda

2016-04-01

Full Text Available Chemical Reaction Networks (CRNs are a formalism to describe the macroscopic behavior of chemical systems. We introduce COEL, a web- and cloud-based CRN simulation framework that does not require a local installation, runs simulations on a large computational grid, provides reliable database storage, and offers a visually pleasing and intuitive user interface. We present an overview of the underlying software, the technologies, and the main architectural approaches employed. Some of COEL's key features include ODE-based simulations of CRNs and multicompartment reaction networks with rich interaction options, a built-in plotting engine, automatic DNA-strand displacement transformation and visualization, SBML/Octave/Matlab export, and a built-in genetic-algorithm-based optimization toolbox for rate constants.COEL is an open-source project hosted on GitHub (http://dx.doi.org/10.5281/zenodo.46544, which allows interested research groups to deploy it on their own sever. Regular users can simply use the web instance at no cost at http://coel-sim.org. The framework is ideally suited for a collaborative use in both research and education.

Towards Formal Implementation of PUS Standard

Science.gov (United States)

Ilić, D.

2009-05-01

As an effort to promote the reuse of on-board and ground systems ESA developed a standard for packet telemetry and telecommand - PUS. It defines a set of standard service models with the corresponding structures of the associated telemetry and telecommand packets. Various missions then can choose to implement those standard PUS services that best conform to their specific requirements. In this paper we propose a formal development (based on the Event-B method) of reusable service patterns, which can be instantiated for concrete application. Our formal models allow us to formally express and verify specific service properties including various telecommand and telemetry packet structure validation.

Thermoelectric properties of semiconductor nanowire networks

Science.gov (United States)

Roslyak, Oleksiy; Piryatinski, Andrei

2016-03-01

To examine the thermoelectric (TE) properties of a semiconductor nanowire (NW) network, we propose a theoretical approach mapping the TE network on a two-port network. In contrast to a conventional single-port (i.e., resistor) network model, our model allows for large scale calculations showing convergence of TE figure of merit, ZT, with an increasing number of junctions. Using this model, numerical simulations are performed for the Bi2Te3 branched nanowire (BNW) and Cayley tree NW (CTNW) network. We find that the phonon scattering at the network junctions plays a dominant role in enhancing the network ZT. Specifically, disordered BNW and CTNW demonstrate an order of magnitude higher ZT enhancement compared to their ordered counterparts. Formation of preferential TE pathways in CTNW makes the network effectively behave as its BNW counterpart. We provide formalism for simulating large scale nanowire networks hinged upon experimentally measurable TE parameters of a single T-junction.

Controllability of Surface Water Networks

Science.gov (United States)

Riasi, M. Sadegh; Yeghiazarian, Lilit

2017-12-01

To sustainably manage water resources, we must understand how to control complex networked systems. In this paper, we study surface water networks from the perspective of structural controllability, a concept that integrates classical control theory with graph-theoretic formalism. We present structural controllability theory and compute four metrics: full and target controllability, control centrality and control profile (FTCP) that collectively determine the structural boundaries of the system's control space. We use these metrics to answer the following questions: How does the structure of a surface water network affect its controllability? How to efficiently control a preselected subset of the network? Which nodes have the highest control power? What types of topological structures dominate controllability? Finally, we demonstrate the structural controllability theory in the analysis of a wide range of surface water networks, such as tributary, deltaic, and braided river systems.

Network structure underlying resolution of conflicting non-verbal and verbal social information.

Science.gov (United States)

Watanabe, Takamitsu; Yahata, Noriaki; Kawakubo, Yuki; Inoue, Hideyuki; Takano, Yosuke; Iwashiro, Norichika; Natsubori, Tatsunobu; Takao, Hidemasa; Sasaki, Hiroki; Gonoi, Wataru; Murakami, Mizuho; Katsura, Masaki; Kunimatsu, Akira; Abe, Osamu; Kasai, Kiyoto; Yamasue, Hidenori

2014-06-01

Social judgments often require resolution of incongruity in communication contents. Although previous studies revealed that such conflict resolution recruits brain regions including the medial prefrontal cortex (mPFC) and posterior inferior frontal gyrus (pIFG), functional relationships and networks among these regions remain unclear. In this functional magnetic resonance imaging study, we investigated the functional dissociation and networks by measuring human brain activity during resolving incongruity between verbal and non-verbal emotional contents. First, we found that the conflict resolutions biased by the non-verbal contents activated the posterior dorsal mPFC (post-dmPFC), bilateral anterior insula (AI) and right dorsal pIFG, whereas the resolutions biased by the verbal contents activated the bilateral ventral pIFG. In contrast, the anterior dmPFC (ant-dmPFC), bilateral superior temporal sulcus and fusiform gyrus were commonly involved in both of the resolutions. Second, we found that the post-dmPFC and right ventral pIFG were hub regions in networks underlying the non-verbal- and verbal-content-biased resolutions, respectively. Finally, we revealed that these resolution-type-specific networks were bridged by the ant-dmPFC, which was recruited for the conflict resolutions earlier than the two hub regions. These findings suggest that, in social conflict resolutions, the ant-dmPFC selectively recruits one of the resolution-type-specific networks through its interaction with resolution-type-specific hub regions. © The Author (2013). Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

Deciding where to attend: Large-scale network mechanisms underlying attention and intention revealed by graph-theoretic analysis.

Science.gov (United States)

Liu, Yuelu; Hong, Xiangfei; Bengson, Jesse J; Kelley, Todd A; Ding, Mingzhou; Mangun, George R

2017-08-15

The neural mechanisms by which intentions are transformed into actions remain poorly understood. We investigated the network mechanisms underlying spontaneous voluntary decisions about where to focus visual-spatial attention (willed attention). Graph-theoretic analysis of two independent datasets revealed that regions activated during willed attention form a set of functionally-distinct networks corresponding to the frontoparietal network, the cingulo-opercular network, and the dorsal attention network. Contrasting willed attention with instructed attention (where attention is directed by external cues), we observed that the dorsal anterior cingulate cortex was allied with the dorsal attention network in instructed attention, but shifted connectivity during willed attention to interact with the cingulo-opercular network, which then mediated communications between the frontoparietal network and the dorsal attention network. Behaviorally, greater connectivity in network hubs, including the dorsolateral prefrontal cortex, the dorsal anterior cingulate cortex, and the inferior parietal lobule, was associated with faster reaction times. These results, shown to be consistent across the two independent datasets, uncover the dynamic organization of functionally-distinct networks engaged to support intentional acts. Copyright © 2017 Elsevier Inc. All rights reserved.

Analysis of Informationization Construction of Business Financial Management under the Network Economy

Science.gov (United States)

Dong, Yahui; Zhang, Pengwei; Li, Wei

To strengthen the informationization construction of the financial management has great significance to the achievement of business management informationization, and under the network economic environment, it is an important task of the financial management that how to conduct informationization construction of traditional financial management to provide true, reliable and complete financial information system for the business managers. This paper thoroughly researches the problem of financial information orientation management (FIOM) by taking the method of combining theory with practice. This paper puts forward the thinking method of financial information management, makes the new contents of E-finance. At last, this paper rebuilds the system of finance internal control from four aspects such as control of organization and management, system development control and safety control of network system.

Survey of Existing Tools for Formal Verification.

Energy Technology Data Exchange (ETDEWEB)

Punnoose, Ratish J.; Armstrong, Robert C.; Wong, Matthew H.; Jackson, Mayo

2014-12-01

Formal methods have come into wide use because of their effectiveness in verifying "safety and security" requirements of digital systems; a set of requirements for which testing is mostly ineffective. Formal methods are routinely used in the design and verification of high-consequence digital systems in industry. This report outlines our work in assessing the capabilities of commercial and open source formal tools and the ways in which they can be leveraged in digital design workflows.

A constructive logic for services and information flow in computer networks

NARCIS (Netherlands)

Borghuis, V.A.J.; Feijs, L.M.G.

2000-01-01

In this paper we introduce a typed -calculus in which computer networks can be formalized and directed at situations where the services available on the network are stationary, while the information can flow freely. For this calculus, an analogue of the ‘propositions-as-types ’interpretation of

Multiverse in the Third Quantized Formalism

International Nuclear Information System (INIS)

Faizal Mir

2014-01-01

In this paper we will analyze the third quantization of gravity in path integral formalism. We will use the time-dependent version of Wheeler—DeWitt equation to analyze the multiverse in this formalism. We will propose a mechanism for baryogenesis to occur in the multiverse, without violating the baryon number conservation. (general)

What are the reasons for clinical network success? A qualitative study.

Science.gov (United States)

McInnes, Elizabeth; Haines, Mary; Dominello, Amanda; Kalucy, Deanna; Jammali-Blasi, Asmara; Middleton, Sandy; Klineberg, Emily

2015-11-05

Clinical networks have been established to improve patient outcomes and processes of care by implementing a range of innovations and undertaking projects based on the needs of local health services. Given the significant investment in clinical networks internationally, it is important to assess their effectiveness and sustainability. This qualitative study investigated the views of stakeholders on the factors they thought were influential in terms of overall network success. Ten participants were interviewed using face-to-face, audio-recorded semi-structured interviews about critical factors for networks' successes over the study period 2006-2008. Respondents were purposively selected from two stakeholder groups: i) chairs of networks during the study period of 2006-2008 from high- moderate- and low-impact networks (as previously determined by an independent review panel) and ii) experts in the clinical field of the network who had a connection to the network but who were not network members. Participants were blind to the performance of the network they were interviewed about. Transcribed data were coded and analysed to generate themes relating to the study aims. Themes relating to influential factors critical to network success were: network model principles; leadership; formal organisational structures and processes; nature of network projects; external relationships; profile and credibility of the network. This study provides clinical networks with guidance on essential factors for maximising optimal network outcomes and that may assist networks to move from being a 'low-impact' to 'high-impact' network. Important ingredients for successful clinical networks were visionary and strategic leadership with strong links to external stakeholders; and having formal infrastructure and processes to enable the development and management of work plans aligned with health priorities.

Informal and Formal Support Groups Retain Women and Minorities in Physics

Science.gov (United States)

Ong, Maria

2005-10-01

Ten U.S. minority female undergraduates who aspire to become physicists were followed over an 8-year period. Participant observation and in-depth interviews recorded the strategies they used to earn bachelor's degrees in physics or physics-related fields, and then go on to graduate school and/or careers in science. One significant strategy these women of color employed was participating in small subcommunities with other women or underrepresented ethnic minorities at the margins of their local physics community. The study found that informal peer groups offered safe spaces to counter negative experiences, to normalize their social realities, and to offer practical guidance for persevering in the field. Formal women- and minority-serving programs in physics provided foundations for community building, stronger curriculum and instruction, networking, and role models. The positive effects of informal and formal support groups on these students' experiences challenge a standard application of Pierre Bourdieu's framework of social and cultural capital. Women of color in the study initially lacked traditional capital of "acceptable" appearance, cultural background and habits, and networks that are more easily acquired by white males and are rewarded by the U.S. physics culture. However, instead of failing or leaving, as Bourdieu's theory would predict, the minority women persisted and achieved in science. The marginal communities contributed to their retention by offering safe spaces in which they could learn and share alternative ways of "accruing capital." Moreover, as these women made strides along their academic and career paths, they also engaged in social justice work in efforts to change the physics culture to be more welcoming of nontraditional members. The outcomes of the study offer empirical confirmation of the critical need for informal and institutionally supported women's and minorities' support groups to promote diversity in science.

Applying the Network Simulation Method for testing chaos in a resistively and capacitively shunted Josephson junction model

Directory of Open Access Journals (Sweden)

Fernando Gimeno Bellver

Full Text Available In this paper, we explore the chaotic behavior of resistively and capacitively shunted Josephson junctions via the so-called Network Simulation Method. Such a numerical approach establishes a formal equivalence among physical transport processes and electrical networks, and hence, it can be applied to efficiently deal with a wide range of differential systems.The generality underlying that electrical equivalence allows to apply the circuit theory to several scientific and technological problems. In this work, the Fast Fourier Transform has been applied for chaos detection purposes and the calculations have been carried out in PSpice, an electrical circuit software.Overall, it holds that such a numerical approach leads to quickly computationally solve Josephson differential models. An empirical application regarding the study of the Josephson model completes the paper. Keywords: Electrical analogy, Network Simulation Method, Josephson junction, Chaos indicator, Fast Fourier Transform

Learning Transferable Features with Deep Adaptation Networks

OpenAIRE

Long, Mingsheng; Cao, Yue; Wang, Jianmin; Jordan, Michael I.

2015-01-01

Recent studies reveal that a deep neural network can learn transferable features which generalize well to novel tasks for domain adaptation. However, as deep features eventually transition from general to specific along the network, the feature transferability drops significantly in higher layers with increasing domain discrepancy. Hence, it is important to formally reduce the dataset bias and enhance the transferability in task-specific layers. In this paper, we propose a new Deep Adaptation...

Changing Conditions for Networked Learning?

DEFF Research Database (Denmark)

Ryberg, Thomas

2011-01-01

in describing the novel pedagogical potentials of these new technologies and practices (e.g. in debates around virtual learning environments versus personal learning environment). Likewise, I shall briefly discuss the notions of ‘digital natives’ or ‘the net generation’ from a critical perspective...... of social technologies. I argue that we are seeing the emergence of new architectures and scales of participation, collaboration and networking e.g. through interesting formations of learning networks at different levels of scale, for different purposes and often bridging boundaries such as formal...

Formal specifications for safety grade systems

International Nuclear Information System (INIS)

Chisholm, G.H.; Smith, B.T.; Wojcik, A.S.

1992-01-01

The authors describe the findings of a study into the application of formal methods to the specification of a safety system for an operating nuclear reactor. They developed a formal specification that is used to verify and validate that no unsafe condition will result from action or inaction of the system. For this reason, the specification must facilitate thinking about, talking about, and implementing the system. In fact, the specification must provide a bridge between people (designers, engineers, policy makers) and diverse implementations (hardware, software, sensors, power supplies) at all levels. For a specification to serve as an effective linkage, it must have the following properties: (1) completeness, (2) conciseness, (3) unambiguity, and (4) communicativeness. In this paper they describe the development of a specification that has three properties. This development is based on the use of formal methods, i.e., methods that add mathematical rigor to the development, analysis and operation of computer systems and to applications based thereon (Neumann). They demonstrate that a specification derived from a formal basis facilitates development of the design and its subsequent verification

Formal truncations of connected kernel equations

International Nuclear Information System (INIS)

Dixon, R.M.

1977-01-01

The Connected Kernel Equations (CKE) of Alt, Grassberger and Sandhas (AGS); Kouri, Levin and Tobocman (KLT); and Bencze, Redish and Sloan (BRS) are compared against reaction theory criteria after formal channel space and/or operator truncations have been introduced. The Channel Coupling Class concept is used to study the structure of these CKE's. The related wave function formalism of Sandhas, of L'Huillier, Redish and Tandy and of Kouri, Krueger and Levin are also presented. New N-body connected kernel equations which are generalizations of the Lovelace three-body equations are derived. A method for systematically constructing fewer body models from the N-body BRS and generalized Lovelace (GL) equations is developed. The formally truncated AGS, BRS, KLT and GL equations are analyzed by employing the criteria of reciprocity and two-cluster unitarity. Reciprocity considerations suggest that formal truncations of BRS, KLT and GL equations can lead to reciprocity-violating results. This study suggests that atomic problems should employ three-cluster connected truncations and that the two-cluster connected truncations should be a useful starting point for nuclear systems

Formalizing Implementation Strategies for First-Class Continuations

DEFF Research Database (Denmark)

Danvy, Olivier

1999-01-01

We present the first formalization of implementation strategies for first-class continuations. The formalization hinges on abstract machines for continuation-passing style (CPS) programs with a special treatment for the current continuation, accounting for the essence of first-class continuations......-class continuations and that second-class continuations are stackable. A large body of work exists on implementing continuations, but it is predominantly empirical and implementation-oriented. In contrast, our formalization abstracts the essence of first-class continuations and provides a uniform setting...

Formalizing Implementation Strategies for First-Class Continuations

DEFF Research Database (Denmark)

Danvy, Olivier

2000-01-01

We present the first formalization of implementation strategies for first-class continuations. The formalization hinges on abstract machines for continuation-passing style (CPS) programs with a special treatment for the current continuation, accounting for the essence of first-class continuations......-class continuations and that second-class continuations are stackable. A large body of work exists on implementing continuations, but it is predominantly empirical and implementation-oriented. In contrast, our formalization abstracts the essence of first-class continuations and provides a uniform setting...

On the Formal Modeling of Games of Language and Adversarial Argumentation : A Logic-Based Artificial Intelligence Approach

OpenAIRE

Eriksson Lundström, Jenny S. Z.

2009-01-01

Argumentation is a highly dynamical and dialectical process drawing on human cognition. Successful argumentation is ubiquitous to human interaction. Comprehensive formal modeling and analysis of argumentation presupposes a dynamical approach to the following phenomena: the deductive logic notion, the dialectical notion and the cognitive notion of justified belief. For each step of an argumentation these phenomena form networks of rules which determine the propositions to be allowed to make se...

Toward a Network Perspective of the Study of Resilience in Social-Ecological Systems

Directory of Open Access Journals (Sweden)

Marco A. Janssen

2006-06-01

Full Text Available Formal models used to study the resilience of social-ecological systems have not explicitly included important structural characteristics of this type of system. In this paper, we propose a network perspective for social-ecological systems that enables us to better focus on the structure of interactions between identifiable components of the system. This network perspective might be useful for developing formal models and comparing case studies of social-ecological systems. Based on an analysis of the case studies in this special issue, we identify three types of social-ecological networks: (1 ecosystems that are connected by people through flows of information or materials, (2 ecosystem networks that are disconnected and fragmented by the actions of people, and (3 artificial ecological networks created by people, such as irrigation systems. Each of these three archytypal social-ecological networks faces different problems that influence its resilience as it responds to the addition or removal of connections that affect its coordination or the diffusion of system attributes such as information or disease.

A Neural Network Model to Learn Multiple Tasks under Dynamic Environments

Science.gov (United States)

Tsumori, Kenji; Ozawa, Seiichi

When environments are dynamically changed for agents, the knowledge acquired in an environment might be useless in future. In such dynamic environments, agents should be able to not only acquire new knowledge but also modify old knowledge in learning. However, modifying all knowledge acquired before is not efficient because the knowledge once acquired may be useful again when similar environment reappears and some knowledge can be shared among different environments. To learn efficiently in such environments, we propose a neural network model that consists of the following modules: resource allocating network, long-term & short-term memory, and environment change detector. We evaluate the model under a class of dynamic environments where multiple function approximation tasks are sequentially given. The experimental results demonstrate that the proposed model possesses stable incremental learning, accurate environmental change detection, proper association and recall of old knowledge, and efficient knowledge transfer.

New Technologies and Learning Environments: A Perspective from Formal and Non-Formal Education in Baja California, Mexico

Science.gov (United States)

Zamora, Julieta Lopez; Reynaga, Francisco Javier Arriaga

2010-01-01

This paper presents results of two research works, the first approaches non-formal education and the second addresses formal education. In both studies in-depth interview techniques were used. There were some points of convergence between them on aspects such as the implementation of learning environments and the integration of ICT. The interview…

Formal verification of industrial control systems

CERN Multimedia

CERN. Geneva

2015-01-01

Verification of critical software is a high priority but a challenging task for industrial control systems. For many kinds of problems, testing is not an efficient method. Formal methods, such as model checking appears to be an appropriate complementary method. However, it is not common to use model checking in industry yet, as this method needs typically formal methods expertise and huge computing power. In the EN-ICE-PLC section, we are working on a [methodology][1] and a tool ([PLCverif][2]) to overcome these challenges and to integrate formal verification in the development process of our PLC-based control systems. [1]: http://cern.ch/project-plc-formalmethods [2]: http://cern.ch/plcverif

Contributions of Social Networking for Innovation

Directory of Open Access Journals (Sweden)

Daniela Maria Cartoni

2013-04-01

Full Text Available This paper investigates the role of virtual social networks as a mechanism complementary to formal channels of technology transfer represented by ICT and by private centers of R & D in industry. The strengthening of Web 2.0 has provided the expansion of collaborative tools, in particular the social networks, with a strong influence on the spread of knowledge and innovation. To evaluate the potential of virtual networks, a survey had been conducted to identify and describe the characteristics of some of the major social networks used in Brazil (LinkedIn, Orkut and Twitter. Even this phenomenon is not mature, the study identified the potential and benefits of social networks as informal structures that help in generation of knowledge and innovation diffusion, as a field to be explored and developed.

Differential network analysis with multiply imputed lipidomic data.

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Maiju Kujala

Full Text Available The importance of lipids for cell function and health has been widely recognized, e.g., a disorder in the lipid composition of cells has been related to atherosclerosis caused cardiovascular disease (CVD. Lipidomics analyses are characterized by large yet not a huge number of mutually correlated variables measured and their associations to outcomes are potentially of a complex nature. Differential network analysis provides a formal statistical method capable of inferential analysis to examine differences in network structures of the lipids under two biological conditions. It also guides us to identify potential relationships requiring further biological investigation. We provide a recipe to conduct permutation test on association scores resulted from partial least square regression with multiple imputed lipidomic data from the LUdwigshafen RIsk and Cardiovascular Health (LURIC study, particularly paying attention to the left-censored missing values typical for a wide range of data sets in life sciences. Left-censored missing values are low-level concentrations that are known to exist somewhere between zero and a lower limit of quantification. To make full use of the LURIC data with the missing values, we utilize state of the art multiple imputation techniques and propose solutions to the challenges that incomplete data sets bring to differential network analysis. The customized network analysis helps us to understand the complexities of the underlying biological processes by identifying lipids and lipid classes that interact with each other, and by recognizing the most important differentially expressed lipids between two subgroups of coronary artery disease (CAD patients, the patients that had a fatal CVD event and the ones who remained stable during two year follow-up.

Schizophrenia alters intra-network functional connectivity in the caudate for detecting speech under informational speech masking conditions.

Science.gov (United States)

Zheng, Yingjun; Wu, Chao; Li, Juanhua; Li, Ruikeng; Peng, Hongjun; She, Shenglin; Ning, Yuping; Li, Liang

2018-04-04

Speech recognition under noisy "cocktail-party" environments involves multiple perceptual/cognitive processes, including target detection, selective attention, irrelevant signal inhibition, sensory/working memory, and speech production. Compared to health listeners, people with schizophrenia are more vulnerable to masking stimuli and perform worse in speech recognition under speech-on-speech masking conditions. Although the schizophrenia-related speech-recognition impairment under "cocktail-party" conditions is associated with deficits of various perceptual/cognitive processes, it is crucial to know whether the brain substrates critically underlying speech detection against informational speech masking are impaired in people with schizophrenia. Using functional magnetic resonance imaging (fMRI), this study investigated differences between people with schizophrenia (n = 19, mean age = 33 ± 10 years) and their matched healthy controls (n = 15, mean age = 30 ± 9 years) in intra-network functional connectivity (FC) specifically associated with target-speech detection under speech-on-speech-masking conditions. The target-speech detection performance under the speech-on-speech-masking condition in participants with schizophrenia was significantly worse than that in matched healthy participants (healthy controls). Moreover, in healthy controls, but not participants with schizophrenia, the strength of intra-network FC within the bilateral caudate was positively correlated with the speech-detection performance under the speech-masking conditions. Compared to controls, patients showed altered spatial activity pattern and decreased intra-network FC in the caudate. In people with schizophrenia, the declined speech-detection performance under speech-on-speech masking conditions is associated with reduced intra-caudate functional connectivity, which normally contributes to detecting target speech against speech masking via its functions of suppressing masking-speech signals.

Business Process Modeling Languages Supporting Collaborative Networks

NARCIS (Netherlands)

Soleimani Malekan, H.; Afsarmanesh, H.; Hammoudi, S.; Maciaszek, L.A.; Cordeiro, J.; Dietz, J.L.G.

2013-01-01

Formalizing the definition of Business Processes (BPs) performed within each enterprise is fundamental for effective deployment of their competencies and capabilities within Collaborative Networks (CN). In our approach, every enterprise in the CN is represented by its set of BPs, so that other

Institutions and development in Mexico. Are formal economic reforms enough?

OpenAIRE

Manuel Palma-Rangel

2006-01-01

This paper examines whether the current political arrangements framing the Mexican politics help in consolidating and advancing those economic reforms that have been implemented in Mexico since the 1982 severe economic crises. I will argue that these arrangements create impediments to the co-ordination required to sustain and advance those policy changes that are needed under the new economic model. Formal and informal institutional environments that do not provide for the adequate enforcemen...

"Passing It On": Beyond Formal or Informal Pedagogies

Science.gov (United States)

Cain, Tim

2013-01-01

Informal pedagogies are a subject of debate in music education, and there is some evidence of teachers abandoning formal pedagogies in favour of informal ones. This article presents a case of one teacher's formal pedagogy and theorises it by comparing it with a case of informal pedagogy. The comparison reveals affordances of formal pedagogies…

An approach of requirements tracing in formal refinement

DEFF Research Database (Denmark)

Jastram, Michael; Hallerstede, Stefan; Leuschel, Michael

2010-01-01

Formal modeling of computing systems yields models that are intended to be correct with respect to the requirements that have been formalized. The complexity of typical computing systems can be addressed by formal refinement introducing all the necessary details piecemeal. We report on preliminar...... changes, making use of corresponding techniques already built into the Event-B method....

Efficiency improvement in proton dose calculations with an equivalent restricted stopping power formalism

Science.gov (United States)

Maneval, Daniel; Bouchard, Hugo; Ozell, Benoît; Després, Philippe

2018-01-01

The equivalent restricted stopping power formalism is introduced for proton mean energy loss calculations under the continuous slowing down approximation. The objective is the acceleration of Monte Carlo dose calculations by allowing larger steps while preserving accuracy. The fractional energy loss per step length ɛ was obtained with a secant method and a Gauss-Kronrod quadrature estimation of the integral equation relating the mean energy loss to the step length. The midpoint rule of the Newton-Cotes formulae was then used to solve this equation, allowing the creation of a lookup table linking ɛ to the equivalent restricted stopping power L eq, used here as a key physical quantity. The mean energy loss for any step length was simply defined as the product of the step length with L eq. Proton inelastic collisions with electrons were added to GPUMCD, a GPU-based Monte Carlo dose calculation code. The proton continuous slowing-down was modelled with the L eq formalism. GPUMCD was compared to Geant4 in a validation study where ionization processes alone were activated and a voxelized geometry was used. The energy straggling was first switched off to validate the L eq formalism alone. Dose differences between Geant4 and GPUMCD were smaller than 0.31% for the L eq formalism. The mean error and the standard deviation were below 0.035% and 0.038% respectively. 99.4 to 100% of GPUMCD dose points were consistent with a 0.3% dose tolerance. GPUMCD 80% falloff positions (R80 ) matched Geant’s R80 within 1 μm. With the energy straggling, dose differences were below 2.7% in the Bragg peak falloff and smaller than 0.83% elsewhere. The R80 positions matched within 100 μm. The overall computation times to transport one million protons with GPUMCD were 31-173 ms. Under similar conditions, Geant4 computation times were 1.4-20 h. The L eq formalism led to an intrinsic efficiency gain factor ranging between 30-630, increasing with the prescribed accuracy of simulations. The

Self-Recovering Sensor-Actor Networks

Directory of Open Access Journals (Sweden)

Maryam Kamali

2010-07-01

Full Text Available Wireless sensor-actor networks are a recent development of wireless networks where both ordinary sensor nodes and more sophisticated and powerful nodes, called actors, are present. In this paper we formalize a recently introduced algorithm that recovers failed actor communication links via the existing sensor infrastructure. We prove via refinement that the recovery is terminating in a finite number of steps and is distributed, thus self-performed by the actors. Most importantly, we prove that the recovery can be done at different levels, via different types of links, such as direct actor links or indirect links between the actors, in the latter case reusing the wireless infrastructure of sensors. This leads to identifying coordination classes, e.g., for delegating the most security sensitive coordination to the direct actor-actor coordination links, the least real-time constrained coordination to indirect links, and the safety critical coordination to both direct actor links and indirect sensor paths between actors. Our formalization is done using the theorem prover in the RODIN platform.

Y-formalism and curved {beta}-{gamma} systems

Energy Technology Data Exchange (ETDEWEB)

Grassi, Pietro Antonio [DISTA, Universita del Piemonte Orientale, via Bellini 25/g, 15100 Alessandria (Italy); INFN - Sezione di Torino (Italy)], E-mail: antonio.pietro.grassi@cern.ch; Oda, Ichiro [Department of Physics, Faculty of Science, University of the Ryukyus, Nishihara, Okinawa 903-0213 (Japan); Tonin, Mario [Dipartimento di Fisica, Universita degli Studi di Padova, INFN, Sezionedi Padova, Via F. Marzolo 8, 35131 Padova (Italy)

2009-01-01

We adopt the Y-formalism to study {beta}-{gamma} systems on hypersurfaces. We compute the operator product expansions of gauge-invariant currents and we discuss some applications of the Y-formalism to model on Calabi-Yau spaces.

Y-formalism and curved β-γ systems

International Nuclear Information System (INIS)

Grassi, Pietro Antonio; Oda, Ichiro; Tonin, Mario

2009-01-01

We adopt the Y-formalism to study β-γ systems on hypersurfaces. We compute the operator product expansions of gauge-invariant currents and we discuss some applications of the Y-formalism to model on Calabi-Yau spaces

The formal operations: Piaget’s concept, researches and main critics

Directory of Open Access Journals (Sweden)

Stepanović Ivana Ž.

2004-01-01

Full Text Available This paper deals with Piaget's concept of formal operations, formal operations researches and critics related to the concept. The first part of the work is dedicated to the formal operations concept. The main characteristics of formal operational thought and formal operations structure, as well as structure logical model are presented in that part of the work. The second part is a review of formal operational researches and it is divided in three parts: (1 problems of researches (2 characteristics of applied methodology and (3 author approaches as a specific research context. In the last part of the work the main critics of formal operations concept are presented and discussed.

Machine learning using a higher order correlation network

Energy Technology Data Exchange (ETDEWEB)

Lee, Y.C.; Doolen, G.; Chen, H.H.; Sun, G.Z.; Maxwell, T.; Lee, H.Y.

1986-01-01

A high-order correlation tensor formalism for neural networks is described. The model can simulate auto associative, heteroassociative, as well as multiassociative memory. For the autoassociative model, simulation results show a drastic increase in the memory capacity and speed over that of the standard Hopfield-like correlation matrix methods. The possibility of using multiassociative memory for a learning universal inference network is also discussed. 9 refs., 5 figs.

Adaptive neural network motion control for aircraft under uncertainty conditions

Science.gov (United States)

Efremov, A. V.; Tiaglik, M. S.; Tiumentsev, Yu V.

2018-02-01

We need to provide motion control of modern and advanced aircraft under diverse uncertainty conditions. This problem can be solved by using adaptive control laws. We carry out an analysis of the capabilities of these laws for such adaptive systems as MRAC (Model Reference Adaptive Control) and MPC (Model Predictive Control). In the case of a nonlinear control object, the most efficient solution to the adaptive control problem is the use of neural network technologies. These technologies are suitable for the development of both a control object model and a control law for the object. The approximate nature of the ANN model was taken into account by introducing additional compensating feedback into the control system. The capabilities of adaptive control laws under uncertainty in the source data are considered. We also conduct simulations to assess the contribution of adaptivity to the behavior of the system.

Application of Formal Methods in Software Engineering

Directory of Open Access Journals (Sweden)

Adriana Morales

2011-12-01

Full Text Available The purpose of this research work is to examine: (1 why are necessary the formal methods for software systems today, (2 high integrity systems through the methodology C-by-C –Correctness-by-Construction–, and (3 an affordable methodology to apply formal methods in software engineering. The research process included reviews of the literature through Internet, in publications and presentations in events. Among the Research results found that: (1 there is increasing the dependence that the nations have, the companies and people of software systems, (2 there is growing demand for software Engineering to increase social trust in the software systems, (3 exist methodologies, as C-by-C, that can provide that level of trust, (4 Formal Methods constitute a principle of computer science that can be applied software engineering to perform reliable process in software development, (5 software users have the responsibility to demand reliable software products, and (6 software engineers have the responsibility to develop reliable software products. Furthermore, it is concluded that: (1 it takes more research to identify and analyze other methodologies and tools that provide process to apply the Formal Software Engineering methods, (2 Formal Methods provide an unprecedented ability to increase the trust in the exactitude of the software products and (3 by development of new methodologies and tools is being achieved costs are not more a disadvantage for application of formal methods.

Theoretical Properties for Neural Networks with Weight Matrices of Low Displacement Rank

OpenAIRE

Zhao, Liang; Liao, Siyu; Wang, Yanzhi; Li, Zhe; Tang, Jian; Pan, Victor; Yuan, Bo

2017-01-01

Recently low displacement rank (LDR) matrices, or so-called structured matrices, have been proposed to compress large-scale neural networks. Empirical results have shown that neural networks with weight matrices of LDR matrices, referred as LDR neural networks, can achieve significant reduction in space and computational complexity while retaining high accuracy. We formally study LDR matrices in deep learning. First, we prove the universal approximation property of LDR neural networks with a ...

Pain: a distributed brain information network?

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Hiroaki Mano

2015-01-01

Full Text Available Understanding how pain is processed in the brain has been an enduring puzzle, because there doesn't appear to be a single "pain cortex" that directly codes the subjective perception of pain. An emerging concept is that, instead, pain might emerge from the coordinated activity of an integrated brain network. In support of this view, Woo and colleagues present evidence that distinct brain networks support the subjective changes in pain that result from nociceptive input and self-directed cognitive modulation. This evidence for the sensitivity of distinct neural subsystems to different aspects of pain opens up the way to more formal computational network theories of pain.

Topspin networks in loop quantum gravity

International Nuclear Information System (INIS)

Duston, Christopher L

2012-01-01

We discuss the extension of loop quantum gravity to topspin networks, a proposal which allows topological information to be encoded in spin networks. We will show that this requires minimal changes to the phase space, C*-algebra and Hilbert space of cylindrical functions. We will also discuss the area and Hamiltonian operators, and show how they depend on the topology. This extends the idea of ‘background independence’ in loop quantum gravity to include topology as well as geometry. It is hoped this work will confirm the usefulness of the topspin network formalism and open up several new avenues for research into quantum gravity. (paper)

Daily rainfall-runoff modelling by neural networks in semi-arid zone ...

African Journals Online (AJOL)

This research work will allow checking efficiency of formal neural networks for flows' modelling of wadi Ouahrane's basin from rainfall-runoff relation which is non-linear. Two models of neural networks were optimized through supervised learning and compared in order to achieve this goal, the first model with input rain, and ...

Formal Analysis of Graphical Security Models

DEFF Research Database (Denmark)

Aslanyan, Zaruhi

, software components and human actors interacting with each other to form so-called socio-technical systems. The importance of socio-technical systems to modern societies requires verifying their security properties formally, while their inherent complexity makes manual analyses impracticable. Graphical...... models for security offer an unrivalled opportunity to describe socio-technical systems, for they allow to represent different aspects like human behaviour, computation and physical phenomena in an abstract yet uniform manner. Moreover, these models can be assigned a formal semantics, thereby allowing...... formal verification of their properties. Finally, their appealing graphical notations enable to communicate security concerns in an understandable way also to non-experts, often in charge of the decision making. This dissertation argues that automated techniques can be developed on graphical security...

MOOCs, Open educational resources and social networking: bridging the gap between informal and formal learning//MOOC, recursos de educación abierto y redes sociales: acortando la distancia entre aprendizaje informal y formal

Directory of Open Access Journals (Sweden)

Niall Sclater

2016-07-01

Full Text Available MOOCs and open educational resources (OER provide a wealth of learning opportunities for people around the globe, many of whom have no access to formal higher education. OER are often difficult to locate and are accessed on their own without support from or dialogue with subject experts and peers. This paper looks at whether it is possible to develop effective learning communities around OER and whether these communities can emerge spontaneously and in a self-organised way without moderation. It examines the complex interplay between formal and informal learning, and examines whether MOOCs are the answer to providing effective interaction and dialogue for those wishing to study at university level for free on the Internet.

Gold-Catalyzed Formal [4+1]/[4+3] Cycloadditions of Diazo Esters with Triazines.

Science.gov (United States)

Zhu, Chenghao; Xu, Guangyang; Sun, Jiangtao

2016-09-19

Reported herein is the unprecedented gold-catalyzed formal [4+1]/[4+3] cycloadditions of diazo esters with hexahydro-1,3,4-triazines, thus providing five- and seven-membered heterocycles in moderate to high yields under mild reaction conditions. These reactions feature the use of a gold complex to accomplish the diverse annulations and the first example of the involvement of a gold metallo-enolcarbene in a cycloaddition. It is also the first utilization of stable triazines as formal dipolar adducts in the carbene-involved cycloadditions. Mechanistic investigations reveal that the triazines reacted directly, rather than as formaldimine precursors, in the reaction process. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Cross-linked structure of network evolution

International Nuclear Information System (INIS)

Bassett, Danielle S.; Wymbs, Nicholas F.; Grafton, Scott T.; Porter, Mason A.; Mucha, Peter J.

2014-01-01

We study the temporal co-variation of network co-evolution via the cross-link structure of networks, for which we take advantage of the formalism of hypergraphs to map cross-link structures back to network nodes. We investigate two sets of temporal network data in detail. In a network of coupled nonlinear oscillators, hyperedges that consist of network edges with temporally co-varying weights uncover the driving co-evolution patterns of edge weight dynamics both within and between oscillator communities. In the human brain, networks that represent temporal changes in brain activity during learning exhibit early co-evolution that then settles down with practice. Subsequent decreases in hyperedge size are consistent with emergence of an autonomous subgraph whose dynamics no longer depends on other parts of the network. Our results on real and synthetic networks give a poignant demonstration of the ability of cross-link structure to uncover unexpected co-evolution attributes in both real and synthetic dynamical systems. This, in turn, illustrates the utility of analyzing cross-links for investigating the structure of temporal networks