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Sample records for networks proposition tarifaire

  1. Whence Structured Propositions?

    ERIC Educational Resources Information Center

    Keller, Lorraine Juliano

    2012-01-01

    This thesis is a critical examination of "Structured Propositionalism" (SP), the view that propositions are complex entities composed of the semantic values of the (meaningful) parts of the sentences that express them. According to SP, propositions have constituents and are individuated by the identity and arrangement of their…

  2. Testing Some Propositions about Proposition 13.

    ERIC Educational Resources Information Center

    Attiyeh, Richard; Engle, Robert F.

    1979-01-01

    Data suggest that voters did recognize the implications of substantial reductions in government expenditures in Proposition 13 and voted to tolerate them. Journal availability: see EA 511 898. (Author/IRT)

  3. Ten Propositions Regarding Spacepower

    NASA Astrophysics Data System (ADS)

    Smith, M. V.

    2001-06-01

    This study rides the coattails of Colonel Phillip S. Meilinger's book, Ten Propositions Regarding Air Power. As the United States ponders its future regarding space operations, the time has come to flame similar propositions regarding spacepower. Specifically, this study seeks to answer the question, "What is the nature of spacepower?" It also tests the aerospace integration school's hypothesis that spacepower is simply a continuation or extension of airpower. Two points come immediately to the forefront of this work. First, spacepower is different from airpower even though both share the vertical dimension of warfare. Second, space operations have matured to a point wherein valid and unique propositions regarding spacepower are identifiable. The ten propositions presented here do not represent a complete list. The method used to derive these propositions involved literary research that resulted in a long list. The list evolved over three years during numerous brainstorming sessions with several space experts most of them space weapons officers with theater and often combat experience until the list was carefully refined into the ten most salient propositions. There were many ways to present the Ten Propositions Regarding Spacepower, but the author deferred to Meilinger's approach of citing each proposition as a thesis statement with supporting material immediately following. The objective of this work is to stimulate discussions and help those who do not yet understand or appreciate the nature of spacepower in modern warfare.

  4. Mate Selection: A Propositional Formulation.

    ERIC Educational Resources Information Center

    Roosa, Mark W.

    With the intent of integrating partial theories that have developed in the area of mate selection, this paper presents propositions extracted from the research literature (1950-1976). A logical ordering of these propositions is suggested and new propositions are derived by interrelating selected propositions. These conclusions are reached: first,…

  5. Proposition 215: a dilemma.

    PubMed

    Mead, A

    1998-01-01

    The author describes the scope of California's Proposition 215 and explains the legal and scientific controversies that surround its enactment. The federal government's response to the law (including its threats to any physicians who might recommend medical marijuana to patients) and the litigation that ensued are outlined. The author recounts the complicated role played by the California Medical Association during this time, as it sought to adhere to the principles of the scientific process while also attempting to resist improper governmental intrusion into the physician-patient relationship. The legal impact of the federal Controlled Substances Act on the availability of marijuana for either research or therapeutic purposes is described. The conflict between Proposition 215 and federal law is explained, and author offers a legal analysis of the extent to which physicians have free speech rights under the federal constitution to discuss and recommend the medical use of marijuana to patients. The California Medical Association's efforts to address and reconcile the competing interests, culminating in written legal guidelines for physicians, are described in detail.

  6. How Students Revise Propositions: An Exploratory Study of Propositional Modification.

    ERIC Educational Resources Information Center

    Falvey, Peter; Sengupta, Sima

    After noting that the revisions made by corporate writers contained significant modifications in the original propositions, to the extent that they may have changed the meaning of the proposition, a study was undertaken to see if the same phenomenon occurred among students and teachers. Subjects were Hong Kong secondary school students and a…

  7. Training propositional reasoning.

    PubMed

    Klauer, K C; Meiser, T; Naumer, B

    2000-08-01

    Two experiments compared the effects of four training conditions on propositional reasoning. A syntactic training demonstrated formal derivations, in an abstract semantic training the standard truth-table definitions of logical connectives were explained, and a domain-specific semantic training provided thematic contexts for the premises of the reasoning task. In a control training, an inductive reasoning task was practised. In line with the account by mental models, both kinds of semantic training were significantly more effective than the control and the syntactic training, whereas there were no significant differences between the control and the syntactic training, nor between the two kinds of semantic training. Experiment 2 replicated this pattern of effects using a different set of syntactic and domain-specific training conditions. PMID:10994233

  8. Complex Knowledge Mastery: Some Propositions.

    ERIC Educational Resources Information Center

    Keller, Joyce A.; Schallert, Diane L.

    The proposition that the mastery of complex tasks embodies several components was studied for 236 students in an undergraduate introductory financial accounting course. A new curriculum was developed for the course that included in-depth exposure to the actual financial statements of a company and the understanding of the structural relationships…

  9. A propositional theory of recognition memory.

    PubMed

    Anderson, J R; Bower, G H

    1974-05-01

    This paper modifies the Anderson and Bower (1972) theory of recognition memory for words. A propositional representation is outlined for the contextual information underlying word recognition. Logical arguments are offered for preferring this representation over the undifferentiated associative representation used earlier. The propositional representation is used to interpret effects of verbal context upon recognition memory. The implications of these context effects are considered for two-process models of recall and recognition. PMID:21274765

  10. Evaluating forensic biology results given source level propositions.

    PubMed

    Taylor, Duncan; Abarno, Damien; Hicks, Tacha; Champod, Christophe

    2016-03-01

    The evaluation of forensic evidence can occur at any level within the hierarchy of propositions depending on the question being asked and the amount and type of information that is taken into account within the evaluation. Commonly DNA evidence is reported given propositions that deal with the sub-source level in the hierarchy, which deals only with the possibility that a nominated individual is a source of DNA in a trace (or contributor to the DNA in the case of a mixed DNA trace). We explore the use of information obtained from examinations, presumptive and discriminating tests for body fluids, DNA concentrations and some case circumstances within a Bayesian network in order to provide assistance to the Courts that have to consider propositions at source level. We use a scenario in which the presence of blood is of interest as an exemplar and consider how DNA profiling results and the potential for laboratory error can be taken into account. We finish with examples of how the results of these reports could be presented in court using either numerical values or verbal descriptions of the results.

  11. Proposition 203: A Critical Metaphor Analysis

    ERIC Educational Resources Information Center

    Johnson, Eric

    2005-01-01

    This project draws on Lakoff and Johnson's (1980) work with metaphor analysis to uncover the rhetorical strategies applied by supporters of the English for the Children organization during the 2000 Arizona Proposition 203 campaign. The data were collected from three sources: (a) "The Arizona Republic"; (b) the "East Valley Tribune"; and (c) the…

  12. California and Proposition 13: A Brief Analysis.

    ERIC Educational Resources Information Center

    Picus, Larry

    In June 1978, California voters approved Proposition 13, limiting property taxes to 1 percent of a property's market value and limiting the property's growth in market value to 2 percent per year. The immediate effect of the limitations was to reduce property tax revenues by $7 billion, of which $3.1 billion would have gone to the schools. The…

  13. The Micropolitics of Innovation: Nine Propositions

    ERIC Educational Resources Information Center

    House, Ernest R.

    1976-01-01

    Presents nine propositions dealing with communication and implementation of innovations. For example, innovation diffusion depends on face-to-face personal contact, the teacher has very limited access to new ideas and innovations, and what is rational for the teacher may not be rational for the administrator or reformer. (Author/IRT)

  14. In Search of the Next Value Proposition

    ERIC Educational Resources Information Center

    Huwe, Terence K.

    2012-01-01

    Although it is pretty easy to find colleagues who will express fatigue or frustration about the constant need for libraries to prove their value proposition, there is also an upside to the exercise of crafting a message that justifies librarians' mission. The catch is that however good their crafted message may be, they must forget about ever…

  15. Propositions to a Marxist Theory of Personality.

    ERIC Educational Resources Information Center

    Smith, Robert J.

    1985-01-01

    Presents propositions fundamental to a comprehensive Marxist theory of personality: five premises about the ontological nature of the person and four about underlying expresssive personality characteristics. Differences between the proposed theory and traditional theories are discussed in terms of sociohistorical influence, the nature of…

  16. Customer value propositions in business markets.

    PubMed

    Anderson, James C; Narus, James A; van Rossum, Wouter

    2006-03-01

    Examples of consumer value propositions that resonate with customers are exceptionally difficult to find. When properly constructed, value propositions force suppliers to focus on what their offerings are really worth. Once companies become disciplined about understanding their customers, they can make smarter choices about where to allocate scarce resources. The authors illuminate the pitfalls of current approaches, then present a systematic method for developing value propositions that are meaningful to target customers and that focus suppliers' efforts on creating superior value. When managers construct a customer value proposition, they often simply list all the benefits their offering might deliver. But the relative simplicity of this all-benefits approach may have a major drawback: benefit assertion. In other words, managers may claim advantages for features their customers don't care about in the least. Other suppliers try to answer the question, Why should our firm purchase your offering instead of your competitor's? But without a detailed understanding of the customer's requirements and preferences, suppliers can end up stressing points of difference that deliver relatively little value to the target customer. The pitfall with this approach is value presumption: assuming that any favorable points of difference must be valuable for the customer. Drawing on the best practices of a handful of suppliers in business markets, the authors advocate a resonating focus approach. Suppliers can provide simple, yet powerfully captivating, consumer value propositions by making their offerings superior on the few elements that matter most to target customers, demonstrating and documenting the value of this superior performance, and communicating it in a way that conveys a sophisticated understanding of the customer's business priorities.

  17. Quantum theory and chemistry: Two propositions

    NASA Technical Reports Server (NTRS)

    Aronowitz, S.

    1980-01-01

    Two propositions concerning quantum chemistry are proposed. First, it is proposed that the nonrelativistic Schroedinger equation, where the Hamiltonian operator is associated with an assemblage of nuclei and electrons, can never be arranged to yield specific molecules in the chemists' sense. It is argued that this result is a necessary condition if the Schroedinger has relevancy to chemistry. Second, once a system is in a particular state with regard to interactions among its components (the assemblage of nuclei and electrons), it cannot spontaneously eliminate any of those interactions. This leads to a subtle form of irreversibility.

  18. Proposition 65 in the dental office.

    PubMed

    Pichay, T J; Seifert, L J

    2001-07-01

    In the mid-1990s, dentistry became included in enforcement activity for Proposition 65, the Safe Drinking Water and Toxic Enforcement Act of 1986. This year, 80 dental offices were served with 60-day notices for failing to post Prop. 65 warnings. The California Dental Association has been inundated with inquiries on what dental offices should be doing with regard to Prop. 65 requirements. This article provides a brief history of Prop. 65 and answers the questions most frequently asked of CDA. PMID:11490690

  19. Interpreting hypernymic propositions in an online medical encyclopedia.

    PubMed

    Fiszman, Marcelo; Rindflesch, Thomas C; Kilicoglu, Halil

    2003-01-01

    Interpretation of semantic propositions from bio-medical texts documents would provide valuable support to natural language processing (NLP) applications. We are developing a methodology to interpret a kind of semantic proposition, the hypernymic proposition, in MEDLINE abstracts. In this paper, we expanded the system to identify these structures in a different discourse domain: the Medical Encyclopedia from the National Library of Medi-cine's MEDLINEplus Website.

  20. The demystification of autoscopic phenomena: experimental propositions.

    PubMed

    Mohr, Christine; Blanke, Olaf

    2005-06-01

    Autoscopic phenomena (AP) are rare, illusory visual experiences during which the subject has the impression of seeing a second own body in extrapersonal space. AP consist of out-of-body experience, autoscopic hallucination, and heautoscopy. Recent neurologic reports support the role of multisensory integration deficits of body-related information and vestibular dysfunctions in AP at the temporo-parietal junction. A caveat to test the underlying neurologic and cognitive mechanisms of AP has been their rare and spontaneous occurrence. Recent evidence linked AP to mental own-body imagery engaging brain mechanisms at the temporo-parietal junction. These recent observations open a new avenue for testing AP-related cognitive mechanisms in selected clinical and normal populations. We review evidence on several clinical syndromes (psychosis, depression, anxiety, depersonalization, body dysmorphic disorder), suggesting that some of these syndromes may relate to AP-proneness, thereby leading to testable propositions for future research on body and self processing in addition to AP.

  1. Bayesian experimental design for identification of model propositions and conceptual model uncertainty reduction

    NASA Astrophysics Data System (ADS)

    Pham, Hai V.; Tsai, Frank T.-C.

    2015-09-01

    The lack of hydrogeological data and knowledge often results in different propositions (or alternatives) to represent uncertain model components and creates many candidate groundwater models using the same data. Uncertainty of groundwater head prediction may become unnecessarily high. This study introduces an experimental design to identify propositions in each uncertain model component and decrease the prediction uncertainty by reducing conceptual model uncertainty. A discrimination criterion is developed based on posterior model probability that directly uses data to evaluate model importance. Bayesian model averaging (BMA) is used to predict future observation data. The experimental design aims to find the optimal number and location of future observations and the number of sampling rounds such that the desired discrimination criterion is met. Hierarchical Bayesian model averaging (HBMA) is adopted to assess if highly probable propositions can be identified and the conceptual model uncertainty can be reduced by the experimental design. The experimental design is implemented to a groundwater study in the Baton Rouge area, Louisiana. We design a new groundwater head observation network based on existing USGS observation wells. The sources of uncertainty that create multiple groundwater models are geological architecture, boundary condition, and fault permeability architecture. All possible design solutions are enumerated using a multi-core supercomputer. Several design solutions are found to achieve an 80%-identifiable groundwater model in 5 years by using six or more existing USGS wells. The HBMA result shows that each highly probable proposition can be identified for each uncertain model component once the discrimination criterion is achieved. The variances of groundwater head predictions are significantly decreased by reducing posterior model probabilities of unimportant propositions.

  2. Leadership, Communicator Style, and Gender: A Propositional Analysis.

    ERIC Educational Resources Information Center

    Sheeler, Kristina K. Horn

    This essay is a propositional analysis of the literature on the interrelationship of communicator style and gender as evidenced in the organizational setting. Pavitt's (1989) notion of the prototype is extended to the realm of organizational communication in developing five propositions: (1) the prototype of the effective manager is more likely to…

  3. The Tyranny of Democracy: Deconstructing the Passage of Racist Propositions

    ERIC Educational Resources Information Center

    Cline, Zulmara; Necochea, Juan; Rios, Francisco

    2004-01-01

    This article examines race-based propositions and the movidas used to garner electorate support for these initiatives, which amount to the "tyranny of the majority" trampling on the rights of the minority as has happened so many times during our nation's history in the name of democracy. Specifically, the passage of Proposition 227 in California…

  4. Testing Propositions Derived from Twitter Studies: Generalization and Replication in Computational Social Science

    PubMed Central

    Liang, Hai; Fu, King-wa

    2015-01-01

    Replication is an essential requirement for scientific discovery. The current study aims to generalize and replicate 10 propositions made in previous Twitter studies using a representative dataset. Our findings suggest 6 out of 10 propositions could not be replicated due to the variations of data collection, analytic strategies employed, and inconsistent measurements. The study’s contributions are twofold: First, it systematically summarized and assessed some important claims in the field, which can inform future studies. Second, it proposed a feasible approach to generating a random sample of Twitter users and its associated ego networks, which might serve as a solution for answering social-scientific questions at the individual level without accessing the complete data archive. PMID:26287530

  5. Testing Propositions Derived from Twitter Studies: Generalization and Replication in Computational Social Science.

    PubMed

    Liang, Hai; Fu, King-Wa

    2015-01-01

    Replication is an essential requirement for scientific discovery. The current study aims to generalize and replicate 10 propositions made in previous Twitter studies using a representative dataset. Our findings suggest 6 out of 10 propositions could not be replicated due to the variations of data collection, analytic strategies employed, and inconsistent measurements. The study's contributions are twofold: First, it systematically summarized and assessed some important claims in the field, which can inform future studies. Second, it proposed a feasible approach to generating a random sample of Twitter users and its associated ego networks, which might serve as a solution for answering social-scientific questions at the individual level without accessing the complete data archive. PMID:26287530

  6. Risk assessment for carcinogens under California's Proposition 65.

    PubMed

    Pease, W S; Zeise, L; Kelter, A

    1990-06-01

    Risk assessments for carcinogens are being developed through an accelerated process in California as a part of the state's implementation of Proposition 65, the Safe Drinking Water and Toxic Enforcement Act. Estimates of carcinogenic potency made by the California Department of Health Services (CDHS) are generally similar to estimates made by the U.S. Environmental Protection Agency (EPA). The largest differences are due to EPA's use of the maximum likelihood estimate instead of CDHS' use of the upper 95% confidence bounds on potencies derived from human data and to procedures used to correct for studies of short duration or with early mortality. Numerical limits derived from these potency estimates constitute "no significant risk" levels, which govern exemption from Proposition 65's discharge prohibition and warning requirements. Under Proposition 65 regulations, lifetime cancer risks less than 10(-5) are not significant and cumulative intake is not considered. Following these regulations, numerical limits for a number of Proposition 65 carcinogens that are applicable to the control of toxic discharges are less stringent than limits under existing federal water pollution control laws. Thus, existing federal limits will become the Proposition 65 levels for discharge. Chemicals currently not covered by federal and state controls will eventually be subject to discharge limitations under Proposition 65. "No significant risk" levels (expressed in terms of daily intake of carcinogens) also trigger warning requirements under Proposition 65 that are more extensive than existing state or federal requirements. A variety of chemical exposures from multiple sources are identified that exceed Proposition 65's "no significant risk" levels. PMID:2367711

  7. [Tridimensional evaluation model of health promotion in school -- a proposition].

    PubMed

    Kulmatycki, Lesław

    2005-01-01

    A good school health programme can be one of the most cost effective investments for simultaneously improving education and health. The general direction of WHO's European Network of Health Promoting Schools and Global Schools Health Initiative is guided by the holistic approach and the Ottawa Charter for Health Promotion (1986). A health promoting school strives to improve the health and well-being of school pupils as well as school personnel, families and community members; and works with community leaders to help them understand how the community contributes to health and education. Evaluation research is essential to describe the nature and effectiveness of school health promoting activity. The overall aim of this paper is to help school leaders and health promotion coordinators to measure their work well and effectively. The specific aim is to offer a practical three-dimensional evaluation model for health promoting schools. The material is presented in two sections. The first one is a 'theoretical base' for health promotion which was identified from broad based daily health promotion practical activities, strategies and intersectional interventions closely related to the philosophy of the holistic approach. The three dimensions refer to: 1. 'areas' -- according to the mandala of health. 2. 'actions' -- according to Ottawa Charter strategies which should be adapted to the local school networks. 3. 'data'-- according to different groups of evidence (process, changes and progress). The second one, as a result of the mentioned base, represents the three 'core elements': standards, criteria and indicators. In conclusion, this article provides a practical answer to the dilemma of the evaluation model in the network of local school environment. This proposition is addressed to school staff and school health promotion providers to make their work as effective as possible to improve pupils health. Health promoting school can be characterized as a school constantly

  8. Making carbon sequestration a paying proposition.

    PubMed

    Han, Fengxiang X; Lindner, Jeff S; Wang, Chuji

    2007-03-01

    Atmospheric carbon dioxide (CO(2)) has increased from a preindustrial concentration of about 280 ppm to about 367 ppm at present. The increase has closely followed the increase in CO(2) emissions from the use of fossil fuels. Global warming caused by increasing amounts of greenhouse gases in the atmosphere is the major environmental challenge for the 21st century. Reducing worldwide emissions of CO(2) requires multiple mitigation pathways, including reductions in energy consumption, more efficient use of available energy, the application of renewable energy sources, and sequestration. Sequestration is a major tool for managing carbon emissions. In a majority of cases CO(2) is viewed as waste to be disposed; however, with advanced technology, carbon sequestration can become a value-added proposition. There are a number of potential opportunities that render sequestration economically viable. In this study, we review these most economically promising opportunities and pathways of carbon sequestration, including reforestation, best agricultural production, housing and furniture, enhanced oil recovery, coalbed methane (CBM), and CO(2) hydrates. Many of these terrestrial and geological sequestration opportunities are expected to provide a direct economic benefit over that obtained by merely reducing the atmospheric CO(2) loading. Sequestration opportunities in 11 states of the Southeast and South Central United States are discussed. Among the most promising methods for the region include reforestation and CBM. The annual forest carbon sink in this region is estimated to be 76 Tg C/year, which would amount to an expenditure of $11.1-13.9 billion/year. Best management practices could enhance carbon sequestration by 53.9 Tg C/year, accounting for 9.3% of current total annual regional greenhouse gas emission in the next 20 years. Annual carbon storage in housing, furniture, and other wood products in 1998 was estimated to be 13.9 Tg C in the region. Other sequestration

  9. Computer thought: propositional attitudes and meta-knowledge

    SciTech Connect

    Dietrich, E.S.

    1985-01-01

    Though artificial intelligence scientists frequently use words such as belief and desire when describing the computational capacities of their programs and computers, they have completely ignored the philosophical and psychological theories of belief and desire. Hence, their explanations of computational capacities that use these terms are frequently little better than folk-psychological explanations. Conversely, though-philosophers and psychologists attempt to couch their theories of belief and desire in computational terms, they have consistently misunderstood the notions of computation and computational semantics. Hence, their theories of such attitudes are frequently inadequate. A computational theory of propositional attitudes (belief and desire) is presented here. It is argued that the theory of propositional attitudes put forth by philosophers and psychologists entails that propositional attitudes are a kind of abstract data type. This refined computational view of propositional attitudes bridges the gap between artificial intelligence, philosophy, and psychology. It is argued that this theory of propositional attitudes has consequences for meta-processing and consciousness in computers.

  10. Reasoning about logical propositions and success in science

    NASA Astrophysics Data System (ADS)

    Piburn, Michael D.

    1990-12-01

    Students display a number of misconceptions when asked to reason about logical propositions. Rather than being random, these misconceptions are stereotypic, and relate to age, ability, and success in science. The grades in science achieved by tenth-grade general science students from two parochial single-sex schools in Australia correlated with their scores on the Propositional Logic Test. The students' ability level was consistently related to the pattern of errors they committed on that measure. Mean scores were lowest on a subtest of ability to use the biconditional and implication, higher on the disjunction, and highest on the conjunction. Success in science was predicted most strongly by the disjunction and biconditional subtests. Knowledge of the way in which a person reasons about logical propositions provides additional insights into the transformations information is subjected to as it is integrated into mental schemata.

  11. The Propositional Logic Induced by Means of Basic Algebras

    NASA Astrophysics Data System (ADS)

    Chajda, I.

    2015-12-01

    A propositional logic induced by means of commutative basic algebras was already described by M. Botur and R. Halaš. It turns out that this is a kind of non-associative fuzzy logic which can be used e.g. in expert systems. Unfortunately, there are other important classes of basic algebras which are not commutative, e.g. orthomodular lattices which are used as an axiomatization of the logic of quantum mechanics. This motivated us to develop another axioms and derivation rules which form a propositional logic induced by basic algebras in general. We show that this logic is algebraizable in the sense of W. J. Blok and D. Pigozzi.

  12. Proposition 13: Is the Worst over for Community Colleges?

    ERIC Educational Resources Information Center

    Lombardi, John

    1979-01-01

    Discusses the ramifications of Proposition 13 in light of cut-backs to community college personnel, programs, and services. Underscores that no aura surrounds the community college. Stresses that the days of unlimited availability of funds for community colleges have ceased. (CM)

  13. Visual Propositions for the Integration of CADD and TRAD.

    ERIC Educational Resources Information Center

    Rodriguez-Ramos, Walter E.

    1987-01-01

    Advances four propositions in an effort to provide a frame of reference for a new generation of interactive engineering graphics scholars. Suggests the integration of traditional engineering graphics with new production tools such as computer-aided design drafting. Proposes that graphics problem-solving educational opportunities be maximized. (CW)

  14. The Pythagorean Proposition, Classics in Mathematics Education Series.

    ERIC Educational Resources Information Center

    Loomis, Elisha Scott

    This book is a reissue of the second edition which appeared in 1940. It has the distinction of being the first vintage mathematical work published in the NCTM series "Classics in Mathematics Education." The text includes a biography of Pythagoras and an account of historical data pertaining to his proposition. The remainder of the book shows 370…

  15. Experience with Proposition 13 and Other Retrenchment Conditions.

    ERIC Educational Resources Information Center

    Bouchard, Donald A.

    1980-01-01

    Declining enrollment and the impact of Proposition 13 are discussed in regard to retrenchment and retention rates. It is suggested that higher education establish meaningful communication and affirmative programming to lessen the effects of retrenchment and cut-backs. (Author/LC)

  16. The HPT Value Proposition in the Larger Improvement Arena.

    ERIC Educational Resources Information Center

    Wallace, Guy W.

    2003-01-01

    Discussion of human performance technology (HPT) emphasizes the key variable, which is the human variable. Highlights include the Ishikawa Diagram; human performance as one variable of process performance; collaborating with other improvement approaches; value propositions; and benefits to stakeholders, including real return on investments. (LRW)

  17. The Propositional Structure of Discourse in the Two Cerebral Hemispheres

    ERIC Educational Resources Information Center

    Long, Debra L.; Baynes, Kathleen; Prat, Chantel S.

    2005-01-01

    Readers construct at least two interrelated representations when they comprehend a text: (a) a representation of the explicit ideas in a text and the relations among them (i.e., a propositional representation) and (b) a representation of the context or situation to which a text refers (i.e., a discourse model). In a recent study, Long and Baynes…

  18. The Analysis of a Propositional Logic Game By Ordering Theory

    ERIC Educational Resources Information Center

    Airasian, Peter W.; And Others

    1975-01-01

    A propositional logic game which is a subtest of the new British intelligence scale was analyzed to determine the extent to which skills proper to a single Piagetian period, formal operations, were hierarchically ordered. Item response patterns from 60 14-year-olds were categorized by means of ordering theory, a boolean algebraic measurement…

  19. The Relationship between Mathematical Induction, Proposition Functions, and Implication Functions

    ERIC Educational Resources Information Center

    Andrew, Lane

    2010-01-01

    In this study, I explored the relationship between mathematical induction ability and proposition and implication functions through a mixed methods approach. Students from three universities (N = 78) and 6 classrooms completed a written assessment testing their conceptual and procedural capabilities with induction and functions. In addition, I…

  20. A Critical Review of Proposition Analysis in Alzheimer's Research and Elsewhere

    ERIC Educational Resources Information Center

    King, James R.

    2012-01-01

    Propositional analysis of text, including the generation of proposition density ratios, is examined within the context of Alzheimer's research. A discussion of linguistic modularity raises questions regarding the outcomes of propositional analysis and its applications in Alzheimer's research. (Contains 1 figure.)

  1. Developmental sequences in class reasoning and propositional reasoning.

    PubMed

    Müller, U; Sokol, B; Overton, W F

    1999-10-01

    This study explored the theoretical prediction that class and propositional reasoning skills emerge as a function of the developing ability to coordinate increasingly complex negation and affirmation operations. Children from Grades 1, 3, 5, and 7 (7-, 9-, 11-, and 13-year-olds) were presented with problems from each domain. Rasch analyses of the children's responses were consistent with the hypothesis that both types of problems measured a single underlying dimension (i.e., the coordination of affirmation and negation operations). Qualitatively distinct levels of class and propositional reasoning were identified along this dimension, adding support to the notion that children's reasoning follows a logical developmental sequence. Planned comparisons supported the order-theoretical prediction that different groups of items account for solution differences between grade levels. Results also indicated that children encounter significant difficulties when they have to reason on the basis of negative information. PMID:10479396

  2. California's Proposition 65: extrapolating animal toxicity to humans.

    PubMed

    Kilgore, W W

    1990-01-01

    In 1986, the voters of California passed a law regarding the concept of extrapolating animal toxicity data to humans. The California Safe Drinking Water and Toxic Enforcement Act of 1986, known as Proposition 65, does five things: 1. It creates a list of chemicals (including a number of agricultural chemicals) known to cause cancer or reproductive toxicity; 2. It limits discharges of listed chemicals to drinking water sources; 3. It requires prior warning before exposure to listed chemicals by anyone in the course of doing business; 4. It creates a list of chemicals requiring testing for carcinogenicity or reproductive toxicity; and 5. It requires the Governor to consult with qualified experts (a 12-member "Scientific Advisory Panel" was appointed) as necessary to carry out his duties. This paper discusses the details and implications of this proposition. Areas of responsibility have been assigned. The definition of significant risk is being addressed. PMID:2248253

  3. Modeling non-monotonic properties under propositional argumentation

    NASA Astrophysics Data System (ADS)

    Wang, Geng; Lin, Zuoquan

    2013-03-01

    In the field of knowledge representation, argumentation is usually considered as an abstract framework for nonclassical logic. In this paper, however, we'd like to present a propositional argumentation framework, which can be used to closer simulate a real-world argumentation. We thereby argue that under a dialectical argumentation game, we can allow non-monotonic reasoning even under classical logic. We introduce two methods together for gaining nonmonotonicity, one by giving plausibility for arguments, the other by adding "exceptions" which is similar to defaults. Furthermore, we will give out an alternative definition for propositional argumentation using argumentative models, which is highly related to the previous reasoning method, but with a simple algorithm for calculation.

  4. Anatomy of a value proposition for laboratory medicine.

    PubMed

    Price, Christopher P; St John, Andrew

    2014-09-25

    Value is now becoming a key driver in the ongoing development of healthcare delivery; key facets include the identification of what is valuable and how that value can be identified, leveraged, and delivered. The concept of a value proposition is widely used in business but can be used in healthcare as a statement of the benefits, costs and value that an organization can deliver to its customers. The foundation of this statement in laboratory medicine is evidence of clinical and cost effectiveness, not only for the patient, but also for other stakeholders involved in the delivery of healthcare, e.g., the carer, service provider, commissioner, purchaser, and the supplier of the test or device, as well as society as a whole. However the value of any laboratory medicine investigation is only achieved if the output (the test result(s)), is acted upon by the initiator of the investigation. Laboratory medicine is one part of a complex intervention, and so the value proposition should encompass the breadth of that intervention - from addressing the unmet need through the generation of clinical, operational and economic outcomes. A value proposition in laboratory medicine is central to successful innovation and quality improvement in healthcare.

  5. Excess electron kinetics by dispersive conductivity: A proposition

    NASA Astrophysics Data System (ADS)

    Schiller, Robert; Nagy, Gabor

    2007-08-01

    A proposition for the simultaneous experimental determination of mobility and scavenger rate coefficient of localized excess electrons is exposed. Based on an earlier theory [Schiller, R., Balog, J., Nagy, G., 2005. Continuous-time random-walk theory of interfering diffusion and chemical reaction with an application to electrochemical impedance spectra of oxidized Zr-1%Nb. J. Chem. Phys. 123, 094704-1-7], it is expected that the steady state conductivity of an insulating liquid, irradiated or illuminated in the presence of some scavenger, depends on frequency. By analyzing the frequency dependence one can obtain the values of the above material properties.

  6. Pushing the envelope: Planning, propositional logic, and stochastic search

    SciTech Connect

    Kautz, H.; Selman, B.

    1996-12-31

    Planning is a notoriously hard combinatorial. search problem. In many interesting domains, current planning algorithms fail to scale up gracefully. By combining a general, stochastic search algorithm and appropriate problem encodings based on propositional logic, we are able to solve hard planning problems many times faster than the best current planning systems. Although stochastic methods have been shown to be very effective on a wide range of scheduling problems, this is the first demonstration of its power on truly challenging classical planning instances. This work also provides a new perspective on representational issues in planning.

  7. Newton's propositions on comets: steps in transition, 1681 - 84.

    NASA Astrophysics Data System (ADS)

    Ruffner, J. A.

    2000-01-01

    Isaac Newton's closest approach to a system of the world in the critical period 1681 - 84 is provided in a set of untitled propositions concerning comets. These notes drastically revise his position maintained against Flamsteed in 1681 and may signal his adoption of a single comet solution for the comet appearances of 1680/81. Points of agreement and difference with the key pre-Principia texts of 1684 - 85 are analysed here. Newton shows substantial control of the phenomena of comet tails, and these concepts change very little in mechanical detail throughout his subsequent work. An emerging theory of gravitation brings planets, their satellites, and comets under the same laws of motion, yet retains a celestial vortex and includes a singular proposition in lieu of the usual formulation of Kepler's area law. The present analysis raises questions on a number of issues of recent Newtonian scholarship, ranging from his achievement following his correspondence with Robert Hooke in 1679 to his veneration of the wisdom of the ancients.

  8. A constructivist theoretical proposition of cultural competence development in nursing.

    PubMed

    Blanchet Garneau, Amélie; Pepin, Jacinthe

    2015-11-01

    Cultural competence development in healthcare professions is considered an essential condition to promote quality and equity in healthcare. Even if cultural competence has been recognized as continuous, evolutionary, dynamic, and developmental by most researchers, current models of cultural competence fail to present developmental levels of this competence. These models have also been criticized for their essentialist perspective of culture and their limited application to competency-based approach programs. To our knowledge, there have been no published studies, from a constructivist perspective, of the processes involved in the development of cultural competence among nurses and undergraduate student nurses. The purpose of this study was to develop a theoretical proposition of cultural competence development in nursing from a constructivist perspective. We used a grounded theory design to study cultural competence development among nurses and student nurses in a healthcare center located in a culturally diverse urban area. Data collection involved participant observation and semi-structured interviews with 24 participants (13 nurses and 11 students) working in three community health settings. The core category, 'learning to bring the different realities together to provide effective care in a culturally diverse context', was constructed using inductive qualitative data analysis. This core category encompasses three dimensions of cultural competence: 'building a relationship with the other', 'working outside the usual practice framework', and 'reinventing practice in action.' The resulting model describes the concurrent evolution of these three dimensions at three different levels of cultural competence development. This study reveals that clinical experience and interactions between students or nurses and their environment both contribute significantly to cultural competence development. The resulting theoretical proposition of cultural competence development

  9. A constructivist theoretical proposition of cultural competence development in nursing.

    PubMed

    Blanchet Garneau, Amélie; Pepin, Jacinthe

    2015-11-01

    Cultural competence development in healthcare professions is considered an essential condition to promote quality and equity in healthcare. Even if cultural competence has been recognized as continuous, evolutionary, dynamic, and developmental by most researchers, current models of cultural competence fail to present developmental levels of this competence. These models have also been criticized for their essentialist perspective of culture and their limited application to competency-based approach programs. To our knowledge, there have been no published studies, from a constructivist perspective, of the processes involved in the development of cultural competence among nurses and undergraduate student nurses. The purpose of this study was to develop a theoretical proposition of cultural competence development in nursing from a constructivist perspective. We used a grounded theory design to study cultural competence development among nurses and student nurses in a healthcare center located in a culturally diverse urban area. Data collection involved participant observation and semi-structured interviews with 24 participants (13 nurses and 11 students) working in three community health settings. The core category, 'learning to bring the different realities together to provide effective care in a culturally diverse context', was constructed using inductive qualitative data analysis. This core category encompasses three dimensions of cultural competence: 'building a relationship with the other', 'working outside the usual practice framework', and 'reinventing practice in action.' The resulting model describes the concurrent evolution of these three dimensions at three different levels of cultural competence development. This study reveals that clinical experience and interactions between students or nurses and their environment both contribute significantly to cultural competence development. The resulting theoretical proposition of cultural competence development

  10. Are Associative and Propositional Processes Qualitatively Distinct? Comment on Gawronski and Bodenhausen (2006)

    ERIC Educational Resources Information Center

    Kruglanski, Arie W.; Dechesne, Mark

    2006-01-01

    The authors comment on B. Gawronski and G. V. Bodenhausen's (2006; see record 2006-10465-003) associative-propositional evaluation model of implicit and explicit attitudes by examining the claims that (a) truth value is attached to propositions but not to associations; (b) pattern activation is qualitatively different from syllogistic structure of…

  11. Exploring Task- and Student-Related Factors in the Method of Propositional Manipulation (MPM)

    ERIC Educational Resources Information Center

    Leppink, Jimmie; Broers, Nick J.; Imbos, Tjaart; van der Vleuten, Cees P. M.; Berger, Martijn P. F.

    2011-01-01

    The method of propositional manipulation (MPM) aims to help students develop conceptual understanding of statistics by guiding them into self-explaining propositions. To explore task- and student-related factors influencing students' ability to learn from MPM, twenty undergraduate students performed six learning tasks while thinking aloud. The…

  12. Rethinking the Value Proposition to Improve Teaching Effectiveness. Rethinking Teacher Compensation

    ERIC Educational Resources Information Center

    Shields, Regis Anne; Lewis, Christopher

    2012-01-01

    All employers, including school districts, enter into a "Value Proposition" with their employees--the complete set of offerings and experiences provided by the employer, compared to other similar opportunities. A successful Value Proposition reflects the needs of both employer and employee, not only attracting and retaining employees with the…

  13. Has California's Passage of Proposition 227 Made a Difference in the Way We Teach?

    ERIC Educational Resources Information Center

    Arellano-Houchin, Anna; Flamenco, Claudia; Merlos, Moises M.; Segura, Lorena

    2001-01-01

    Examined how teachers were impacted by California's Proposition 227, highlighting changes in teaching styles and beliefs about the proposition and its effectiveness. Teachers had to change their teaching strategies to accommodate the new curriculum. They were not sufficiently trained for immediate implementation of English-only education. Teaching…

  14. Gann Limit & Proposition 13: Negative Effects on Local Government Agencies, Inlcuding Schools & Community College Districts.

    ERIC Educational Resources Information Center

    Rodda, Albert S.

    In fall 1978, Paul Gann, who worked with Howard Jarvis to pass California's Proposition 13 in June 1978, sought to qualify an intitiative placing a constitutional limit on state and local government expenditures. This initiative qualified and was approved by voters in November 1979 as Proposition 4. Gann's solicitation set the limitation's base…

  15. Propositional Integration and World-Knowledge Inference: Processes in Understanding "Because" Sentences

    ERIC Educational Resources Information Center

    Cozijn, Reinier; Noordman, Leo G. M.; Vonk, Wietske

    2011-01-01

    The issue addressed in this study is whether propositional integration and world-knowledge inference can be distinguished as separate processes during the comprehension of Dutch "omdat" (because) sentences. "Propositional integration" refers to the process by which the reader establishes the type of relation between two clauses or sentences.…

  16. Four Invalid Propositions about Equality, Efficiency, and Integenerational Transfers through Schooling.

    ERIC Educational Resources Information Center

    Conlisk, John

    1984-01-01

    Four propositions that have been advanced on the basis of verbal intuition are considered. They are given precise interpretation in a formal model and then disproved. The propositions concern intergenerational transfers through schooling; in particular, they concern equality-efficiency conflicts, net benefit calculation, and the role of genetic…

  17. Predictors of Short-Term Treatment Outcomes among California's Proposition 36 Participants

    ERIC Educational Resources Information Center

    Hser, Yih-Ing; Evans, Elizabeth; Teruya, Cheryl; Huang, David; Anglin, M. Douglas

    2007-01-01

    California's voter-initiated Proposition 36 offers non-violent drug offenders community-based treatment as an alternative to incarceration or probation without treatment. This article reports short-term treatment outcomes subsequent to this major shift in drug policy. Data are from 1104 individuals randomly selected from all Proposition 36…

  18. The Initial Impact of Proposition 227 on the Instruction of English Learners.

    ERIC Educational Resources Information Center

    Gandara, Patricia; Maxwell-Jolly, Julie; Garcia, Eugene; Asato, Jolynn; Gutierrez, Kris; Stritikus, Tom; Curry, Julia

    In 1998, California passed Proposition 227, which severely restricted the use of primary language for instructing English learners, calling for a 1-year transitional program of structured English immersion. Researchers examined the effects of Proposition 227 in districts and schools statewide during the first year of implementation. Data from…

  19. Fast Context Switching in Real-Time Propositional Reasoning

    NASA Technical Reports Server (NTRS)

    Nayak, P. Pandurang; Williams, Brian C.

    1997-01-01

    The trend to increasingly capable and affordable control processors has generated an explosion of embedded real-time gadgets that serve almost every function imaginable. The daunting task of programming these gadgets is greatly alleviated with real-time deductive engines that perform all execution and monitoring functions from a single core model, Fast response times are achieved using an incremental propositional deductive database (an LTMS). Ideally the cost of an LTMS's incremental update should be linear in the number of labels that change between successive contexts. Unfortunately an LTMS can expend a significant percentage of its time working on labels that remain constant between contexts. This is caused by the LTMS's conservative approach: a context switch first removes all consequences of deleted clauses, whether or not those consequences hold in the new context. This paper presents a more aggressive incremental TMS, called the ITMS, that avoids processing a significant number of these consequences that are unchanged. Our empirical evaluation for spacecraft control shows that the overhead of processing unchanged consequences can be reduced by a factor of seven.

  20. Longitudinal change in language production: effects of aging and dementia on grammatical complexity and propositional content.

    PubMed

    Kemper, S; Marquis, J; Thompson, M

    2001-12-01

    Mixed modeling was used to examine longitudinal changes in linguistic ability in healthy older adults and older adults with dementia. Language samples, vocabulary scores, and digit span scores were collected annually from healthy older adults and semiannually from older adults with dementia. The language samples were scored for grammatical complexity and propositional content. For the healthy group, age-related declines in grammatical complexity and propositional content were observed. The declines were most rapid in the mid 70s. For the group with dementia, grammatical complexity and propositional content also declined over time, regardless of age. Rates of decline were uniform across individuals. These analyses reveal how both grammatical complexity and propositional content are related to late-life changes in cognition in healthy older adults aswell as those with dementia. Alzheimer's disease accelerates this decline, regardless of age.

  1. Comments on "The Acquisition of Propositional Logic and Formal Operational Schemata during the Secondary School Years."

    ERIC Educational Resources Information Center

    Treagust, David F.

    1979-01-01

    Comments on the study reported by Lawson, Karplus, and Adi (1978) which indicated that formal schemata and propositional logic are not part of the same structured unity of mental operations proposed by Piaget. (HM)

  2. Associative and propositional processes in evaluation: an integrative review of implicit and explicit attitude change.

    PubMed

    Gawronski, Bertram; Bodenhausen, Galen V

    2006-09-01

    A central theme in recent research on attitudes is the distinction between deliberate, "explicit" attitudes and automatic, "implicit" attitudes. The present article provides an integrative review of the available evidence on implicit and explicit attitude change that is guided by a distinction between associative and propositional processes. Whereas associative processes are characterized by mere activation independent of subjective truth or falsity, propositional reasoning is concerned with the validation of evaluations and beliefs. The proposed associative-propositional evaluation (APE) model makes specific assumptions about the mutual interplay of the 2 processes, implying several mechanisms that lead to symmetric or asymmetric changes in implicit and explicit attitudes. The model integrates a broad range of empirical evidence and implies several new predictions for implicit and explicit attitude change.

  3. Propositional reasoning: the differential contribution of "rules" to the difficulty of complex reasoning problems.

    PubMed

    Rijmen, F; De Boeck, P

    2001-01-01

    In Experiment 1, complex propositional reasoning problems were constructed as a combination of several types of logical inferences: modus ponens, modus tollens, disjunctive modus ponens, disjunctive syllogism, and conjunction. Rule theories of propositional reasoning can account for how one combines these inferences, but the difficulty of the problems can be accounted for only if a differential psychological cost is allowed for different basic rules. Experiment 2 ruled out some alternative explanations for these differences that did not refer to the intrinsic difficulty of the basic rules. It was also found that part of the results could be accounted for by the notion of representational cost, as it is used in the mental model theory of propositional reasoning. However, the number of models as a measure of representational cost seems to be too coarsely defined to capture all of the observed effects. PMID:11277459

  4. Drug treatment program compliance and resistance activities during implementation of California's Proposition 36.

    PubMed

    Reynolds, Grace

    2009-01-01

    The Substance Abuse and Crime Prevention Act (SACPA), also known as Proposition 36, was implemented statewide in 2001 in California. This legislation remands non-violent drug offenders to drug treatment rather than prison or jail. Structured telephone interviews were conducted with a purposive sample of 72 drug treatment programs from six Southern California counties concerning compliance and resistance activities during implementation. A linear regression model was developed that used a dependent variable capturing overall experience with Proposition 36 and compliance and resistance activities as independent variables. The final model included three compliance variables (sharing problems and solutions with other treatment providers, hiring new staff, acquiring additional space through rental or purchase) that were most predictive of the programs' overall experience with Proposition 36. The implications of these findings in the context of organizational compliance and resistance activities are discussed.

  5. Consumer demand as a driver of improved working conditions: the 'Ergo-Brand' proposition.

    PubMed

    Neumann, W Patrick; Dixon, Shane M; Nordvall, Anna-Carin

    2014-01-01

    This article develops and explores the 'Ergo-Brand' proposition, which posits that consumers may prefer to buy goods that are made under good working conditions (GWCs). This preference would enhance a differentiation strategy for companies, thereby fostering the application of ergonomics in production. This proposition is developed in the context of a narrative review of the literature on 'ethical consumerism'. This is supplemented with a survey study, conducted in both Canada and Sweden (n = 141) to explore this proposition. Results indicate that consumers would prefer goods made under GWCs, but not unconditionally as quality and price concerns were ranked higher. Access to information on the working conditions in production was seen as a barrier. Nevertheless, the Ergo-Brand concept may be a viable avenue in promoting attention towards ergonomics in companies - particularly if consumer habits are subject to intervention by advertising. Further research on this strategy is warranted.

  6. Consumer demand as a driver of improved working conditions: the 'Ergo-Brand' proposition.

    PubMed

    Neumann, W Patrick; Dixon, Shane M; Nordvall, Anna-Carin

    2014-01-01

    This article develops and explores the 'Ergo-Brand' proposition, which posits that consumers may prefer to buy goods that are made under good working conditions (GWCs). This preference would enhance a differentiation strategy for companies, thereby fostering the application of ergonomics in production. This proposition is developed in the context of a narrative review of the literature on 'ethical consumerism'. This is supplemented with a survey study, conducted in both Canada and Sweden (n = 141) to explore this proposition. Results indicate that consumers would prefer goods made under GWCs, but not unconditionally as quality and price concerns were ranked higher. Access to information on the working conditions in production was seen as a barrier. Nevertheless, the Ergo-Brand concept may be a viable avenue in promoting attention towards ergonomics in companies - particularly if consumer habits are subject to intervention by advertising. Further research on this strategy is warranted. PMID:24840257

  7. Source Separation with One Ear: Proposition for an Anthropomorphic Approach

    NASA Astrophysics Data System (ADS)

    Rouat, Jean; Pichevar, Ramin

    2005-12-01

    We present an example of an anthropomorphic approach, in which auditory-based cues are combined with temporal correlation to implement a source separation system. The auditory features are based on spectral amplitude modulation and energy information obtained through 256 cochlear filters. Segmentation and binding of auditory objects are performed with a two-layered spiking neural network. The first layer performs the segmentation of the auditory images into objects, while the second layer binds the auditory objects belonging to the same source. The binding is further used to generate a mask (binary gain) to suppress the undesired sources from the original signal. Results are presented for a double-voiced (2 speakers) speech segment and for sentences corrupted with different noise sources. Comparative results are also given using PESQ (perceptual evaluation of speech quality) scores. The spiking neural network is fully adaptive and unsupervised.

  8. If the Real World Were Irrelevant, so to Speak: The role of propositional truth-value in counterfactual sentence comprehension

    ERIC Educational Resources Information Center

    Nieuwland, Mante S.; Martin, Andrea E.

    2012-01-01

    Propositional truth-value can be a defining feature of a sentence's relevance to the unfolding discourse, and establishing propositional truth-value in context can be key to successful interpretation. In the current study, we investigate its role in the comprehension of counterfactual conditionals, which describe imaginary consequences of…

  9. An Alternative Proposition to Lewis' Views on the "Constructions of Professional Identity in a Dynamic Higher Education Sector"

    ERIC Educational Resources Information Center

    Feather, Denis

    2015-01-01

    This paper offers an alternative proposition to that of Lewis on identity and professional identity in higher education (HE). The proposition is provided from the narratives of 26 individual interviewees who deliver HE in college-based higher education, a viewpoint not considered by Lewis, who tends to adopt a more generalist view. Where Lewis…

  10. Proposition 13--First Year Effects: An ACCT Special Report to Trustees and Chief Executives of California's Community Colleges.

    ERIC Educational Resources Information Center

    Meardy, William H.

    To assess the first year effects of Proposition 13, informal interviews and discussions were conducted with the college presidents and trustees at 37 California community colleges in January 1979. As a whole, the college boards were committed to carrying out the mandate of Proposition 13, though there seemed to be a struggle as to who would…

  11. Two Propositions on the Application of Point Elasticities to Finite Price Changes.

    ERIC Educational Resources Information Center

    Daskin, Alan J.

    1992-01-01

    Considers counterintuitive propositions about using point elasticities to estimate quantity changes in response to price changes. Suggests that elasticity increases with price along a linear demand curve, but falling quantity demand offsets it. Argues that point elasticity with finite percentage change in price only approximates percentage change…

  12. Associative and Propositional Processes in Evaluation: An Integrative Review of Implicit and Explicit Attitude Change

    ERIC Educational Resources Information Center

    Gawronski, Bertram; Bodenhausen, Galen V.

    2006-01-01

    A central theme in recent research on attitudes is the distinction between deliberate, "explicit" attitudes and automatic, "implicit" attitudes. The present article provides an integrative review of the available evidence on implicit and explicit attitude change that is guided by a distinction between associative and propositional processes.…

  13. The Propositional Logic Test as a Diagnostic Tool for Misconceptions about Logical Operations.

    ERIC Educational Resources Information Center

    Almstrum, Vicki L.

    1999-01-01

    Describes a simple 16-item instrument, the Propositional Logic Test (PLT), that is based on Piagetian theory and a study that explored the use of the PLT in diagnosing student misunderstandings. Analysis of individual student responses revealed a number of systematic errors in interpreting the logical operations in the PLT items. (Contains 23…

  14. Expansion and Equity in Australian Higher Education: Three Propositions for New Relations

    ERIC Educational Resources Information Center

    Gale, Trevor

    2011-01-01

    This article outlines three broad propositions for student equity in Australian higher education (HE), arising from the Australian Government's recent policy announcement to expand and widen student participation. The first is that a new relationship between student demand for places and their supply is on the horizon, unlike any other in…

  15. Propositions Toward the Survival of a Self-Endangered Species: The Fundamental Question.

    ERIC Educational Resources Information Center

    Brandwein, Paul F.

    The author considers the search for a better, pollution-free environment and the political processes by which various groups attempt to influence or control the actions of others in the context. He defines the goal of conservation as a recognition of the interdependence of man and his environment and lists 13 propositions which indicate the urgent…

  16. Cognitive Incoherence of Students regarding the Establishment of Universality of Propositions through Experimentation/Measurement

    ERIC Educational Resources Information Center

    Miyazaki, Mikio

    2008-01-01

    The purpose of this research is to construct a conceptual framework for use in capturing students' unstable perception regarding the establishment of the universality of propositions through experimentation/measurement in school geometry. As a conceptual framework, this research uses a quadrangular-pyramid model comprised of five representative…

  17. The Effectiveness of Propositional Manipulation as a Lecturing Method in the Statistics Knowledge Domain

    ERIC Educational Resources Information Center

    Leppink, Jimmie; Broers, Nick J.; Imbos, Tjaart; van der Vleuten, Cees P. M.; Berger, Martijn P. F.

    2013-01-01

    The current experiment examined the potential effects of the method of propositional manipulation (MPM) as a lecturing method on motivation to learn and conceptual understanding of statistics. MPM aims to help students develop conceptual understanding by guiding them into self-explanation at two different stages: First, at the stage of…

  18. The Impact of Proposition 13 on Public Employee Relations: The Case of Los Angeles.

    ERIC Educational Resources Information Center

    Swimmer, Gene

    1982-01-01

    The impact of Proposition 13 and subsequent state bailout legislation on public employee relations in the City and County of Los Angeles (California) has been a new collective bargaining environment. The 1979 negotiations, where a countywide strike was narrowly averted, illustrate the hardening of management attitudes and union militancy. (MLF)

  19. Acquiring Academic English in One Year: An Unlikely Proposition for English Language Learners

    ERIC Educational Resources Information Center

    Guerrero, Michael D.

    2004-01-01

    This article examines the primary assumption underlying the recent passage of propositions aimed at meeting the need of English language learners (ELLs). The assumption is that English language learners normally need only one year of intensive structured English immersion to learn English well enough to be academically successful in an all-English…

  20. Teaching Semantic Tableaux Method for Propositional Classical Logic with a CAS

    ERIC Educational Resources Information Center

    Aguilera-Venegas, Gabriel; Galán-García, José Luis; Galán-García, María Ángeles; Rodríguez-Cielos, Pedro

    2015-01-01

    Automated theorem proving (ATP) for Propositional Classical Logic is an algorithm to check the validity of a formula. It is a very well-known problem which is decidable but co-NP-complete. There are many algorithms for this problem. In this paper, an educationally oriented implementation of Semantic Tableaux method is described. The program has…

  1. Some School Finance Issues Related to the Implementation of Serrano and Proposition 13.

    ERIC Educational Resources Information Center

    Wickert, Donald

    1985-01-01

    This article reviews the current status of school finance in California in the aftermath of Proposition 13 and the Serrano v. Priest decision (which required determination of school funding on some basis other than district property wealth). Specific trends and directions regarding reform issues of the future are identified. (TE)

  2. Mitigating Chaos: California's Community Colleges in the Post-Proposition 13 Period.

    ERIC Educational Resources Information Center

    Hayward, Gerald C.

    1986-01-01

    The experience of California's community colleges in coping with the crisis created by Proposition 13 suggests that there are elements in institutional finance, mission, governance, planning, decision making, and information systems that can be monitored and manipulated to avoid administrative chaos in times of change. (MSE)

  3. Language and Ageing--Exploring Propositional Density in Written Language--Stability over Time

    ERIC Educational Resources Information Center

    Spencer, Elizabeth; Craig, Hugh; Ferguson, Alison; Colyvas, Kim

    2012-01-01

    This study investigated the stability of propositional density (PD) in written texts, as this aspect of language shows promise as an indicator and as a predictor of language decline with ageing. This descriptive longitudinal study analysed written texts obtained from the Australian Longitudinal Study of Women's Health in which participants were…

  4. Affirmative Action and University Fit: Evidence from Proposition 209. CEP Discussion Paper No. 1224

    ERIC Educational Resources Information Center

    Arcidiacono, Peter; Aucejo, Esteban; Coate, Patrick; Hotz, V. Joseph

    2013-01-01

    Proposition 209 banned the use of racial preferences in admissions at public colleges in California. We analyze unique data for all applicants and enrollees within the University of California (UC) system before and after Prop 209. After Prop 209, graduation rates increased by 4.4%. We present evidence that certain institutions are better at…

  5. The Tantric Proposition in Leadership Education: You Make Me Feel Like a Natural Woman.

    ERIC Educational Resources Information Center

    Wislocki-Goin, Marsha

    This paper argues that leadership in higher education should be open to a female leadership model expressed in an Eastern "Tantric" model. Suggesting that a male leadership model that oppresses and excludes women has been in effect for the past millennium, the proposed Tantric proposition is a step toward a shared model of leadership which will be…

  6. The Role of Identity in Acculturation among Immigrant People: Theoretical Propositions, Empirical Questions, and Applied Recommendations

    ERIC Educational Resources Information Center

    Schwartz, Seth J.; Montgomery, Marilyn J.; Briones, Ervin

    2006-01-01

    The present paper advances theoretical propositions regarding the relationship between acculturation and identity. The most central thesis argued is that acculturation represents changes in cultural identity and that personal identity has the potential to "anchor" immigrant people during their transition to a new society. The article emphasizes…

  7. Equal Opportunity in Higher Education: The Past and Future of California's Proposition 209

    ERIC Educational Resources Information Center

    Grodsky, Eric, Ed.; Kurlaender, Michal, Ed.

    2010-01-01

    This timely book examines issues pertaining to equal opportunity--affirmative action, challenges to it, and alternatives for improving opportunities for underrepresented groups--in higher education today. Its starting point is California's Proposition 209, which ended race-based affirmative action in public education and the workplace in 1996. The…

  8. Idiosyncratic Deals: Testing Propositions on Timing, Content, and the Employment Relationship

    ERIC Educational Resources Information Center

    Rousseau, Denise M.; Hornung, Severin; Kim, Tai Gyu

    2009-01-01

    This study tests propositions regarding idiosyncratic deals (i-deals) in a sample of N = 265 hospital employees using structural equation modeling. Timing and content of idiosyncratic employment arrangements are postulated to have differential consequences for the nature of the employment relationship. Results confirm that i-deals made after hire…

  9. Local Semantic Trace: A Method to Analyze Very Small and Unstructured Texts for Propositional Knowledge

    ERIC Educational Resources Information Center

    Pirnay-Dummer, Pablo

    2015-01-01

    A local semantic trace is a certain quasi-propositional structure that can still be reconstructed from written content that is incomplete or does not follow a proper grammar. It can also retrace bits of knowledge from text containing only very few words, making the microstructure of these artifacts of knowledge externalization available for…

  10. Community College Financing in the Post-Proposition 13 Era. Junior College Resource Review.

    ERIC Educational Resources Information Center

    Lombardi, John

    Tax reduction and limitation of government spending issues dominated the November 1978 state and national elections. What effect the propositions will have on community college financing will not be known for some time. Three principal sources of college revenue--property tax, state appropriations, tuition and fees--account for most of the funds…

  11. The Political Discourse of the Campaign against Bilingual Education: From "Proposition 227" to "Horne v. Flores"

    ERIC Educational Resources Information Center

    Yamagami, Mai

    2012-01-01

    Using the frameworks of critical discourse analysis, representation theory, and legitimization theory, this study examines the political discourse of the campaign for Proposition 227 in California--particularly, the key social representations of languages, their speakers, and the main political actors in the campaign. The analysis examines the…

  12. The Impact of Proposition 13 on Community Services for California Community Colleges.

    ERIC Educational Resources Information Center

    Garlock, Jerry C.

    Fifty-seven percent (60) of California's community colleges responded to a questionnaire surveying the impact of Proposition 13 cutbacks on the budget and number of full-time employees in the area of community services. For the colleges investigated, the total community services budget was $18,330,616 for 1977-1978 and $9,081,933 for 1978-1979.…

  13. The importance of distinguishing information from evidence/observations when formulating propositions.

    PubMed

    Hicks, T; Biedermann, A; de Koeijer, J A; Taroni, F; Champod, C; Evett, I W

    2015-12-01

    The value of forensic results crucially depends on the propositions and the information under which they are evaluated. For example, if a full single DNA profile for a contemporary marker system matching the profile of Mr A is assessed, given the propositions that the DNA came from Mr A and given it came from an unknown person, the strength of evidence can be overwhelming (e.g., in the order of a billion). In contrast, if we assess the same result given that the DNA came from Mr A and given it came from his twin brother (i.e., a person with the same DNA profile), the strength of evidence will be 1, and therefore neutral, unhelpful and irrelevant(1) to the case at hand. While this understanding is probably uncontroversial and obvious to most, if not all practitioners dealing with DNA evidence, the practical precept of not specifying an alternative source with the same characteristics as the one considered under the first proposition may be much less clear in other circumstances. During discussions with colleagues and trainees, cases have come to our attention where forensic scientists have difficulty with the formulation of propositions. It is particularly common to observe that results (e.g., observations) are included in the propositions, whereas-as argued throughout this note-they should not be. A typical example could be a case where a shoe-mark with a logo and the general pattern characteristics of a Nike Air Jordan shoe is found at the scene of a crime. A Nike Air Jordan shoe is then seized at Mr A's house and control prints of this shoe compared to the mark. The results (e.g., a trace with this general pattern and acquired characteristics corresponding to the sole of Mr A's shoe) are then evaluated given the propositions 'The mark was left by Mr A's Nike Air Jordan shoe-sole' and 'The mark was left by an unknown Nike Air Jordan shoe'. As a consequence, the footwear examiner will not evaluate part of the observations (i.e., the mark presents the general

  14. The importance of distinguishing information from evidence/observations when formulating propositions.

    PubMed

    Hicks, T; Biedermann, A; de Koeijer, J A; Taroni, F; Champod, C; Evett, I W

    2015-12-01

    The value of forensic results crucially depends on the propositions and the information under which they are evaluated. For example, if a full single DNA profile for a contemporary marker system matching the profile of Mr A is assessed, given the propositions that the DNA came from Mr A and given it came from an unknown person, the strength of evidence can be overwhelming (e.g., in the order of a billion). In contrast, if we assess the same result given that the DNA came from Mr A and given it came from his twin brother (i.e., a person with the same DNA profile), the strength of evidence will be 1, and therefore neutral, unhelpful and irrelevant(1) to the case at hand. While this understanding is probably uncontroversial and obvious to most, if not all practitioners dealing with DNA evidence, the practical precept of not specifying an alternative source with the same characteristics as the one considered under the first proposition may be much less clear in other circumstances. During discussions with colleagues and trainees, cases have come to our attention where forensic scientists have difficulty with the formulation of propositions. It is particularly common to observe that results (e.g., observations) are included in the propositions, whereas-as argued throughout this note-they should not be. A typical example could be a case where a shoe-mark with a logo and the general pattern characteristics of a Nike Air Jordan shoe is found at the scene of a crime. A Nike Air Jordan shoe is then seized at Mr A's house and control prints of this shoe compared to the mark. The results (e.g., a trace with this general pattern and acquired characteristics corresponding to the sole of Mr A's shoe) are then evaluated given the propositions 'The mark was left by Mr A's Nike Air Jordan shoe-sole' and 'The mark was left by an unknown Nike Air Jordan shoe'. As a consequence, the footwear examiner will not evaluate part of the observations (i.e., the mark presents the general

  15. Plug-In Hybrid Electric Vehicle Value Proposition Study: Phase 1, Task 2: Select Value Propositions/Business Model for Further Study

    SciTech Connect

    Sikes, Karen R; Markel, Lawrence C; Hadley, Stanton W; Hinds, Shaun

    2008-04-01

    The Plug-In Hybrid Electric Vehicle (PHEV) Value Propositions Workshop held in Washington, D.C. in December 2007 served as the Task 1 Milestone for this study. Feedback from all five Workshop breakout sessions has been documented in a Workshop Summary Report, which can be found at www.sentech.org/phev. In this report, the project team compiled and presented a comprehensive list of potential value propositions that would later serve as a 'grab bag' of business model components in Task 2. After convening with the Guidance and Evaluation Committee and other PHEV stakeholders during the Workshop, several improvements to the technical approach were identified and incorporated into the project plan to present a more realistic and accurate case study and evaluation. The assumptions and modifications that will have the greatest impact on the case study selection process in Task 2 are described in more detail in this deliverable. The objective of Task 2 is to identify the combination of value propositions that is believed to be achievable by 2030 and collectively hold promise for a sustainable PHEV market by 2030. This deliverable outlines what the project team (with input from the Committee) has defined as its primary scenario to be tested in depth for the remainder of Phase 1. Plans for the second and third highest priority/probability business scenarios are also described in this deliverable as proposed follow up case studies in Phase 2. As part of each case study description, the proposed utility system (or subsystem), PHEV market segment, and facilities/buildings are defined.

  16. Networks.

    ERIC Educational Resources Information Center

    Cerf, Vinton G.

    1991-01-01

    The demands placed on the networks transporting the information and knowledge generated by the increased diversity and sophistication of computational machinery are described. What is needed to support this increased flow, the structures already in place, and what must be built are topics of discussion. (KR)

  17. Water quality improvement by implementation of Proposition O in the Los Angeles river watershed, California.

    PubMed

    Park, Mi-Hyun; Pincetl, Stephanie; Stenstrom, Michael K

    2008-01-01

    Proposition O was created to help the City of Los Angeles comply with the Total Maximum Daily Load (TMDL) requirements under the Clean Water Act. In this study, the effectiveness of the Proposition O projects in Los Angeles River watershed was examined to show whether it achieves the goal of meeting water quality standards. Our analysis shows the most effective single project will remove at most 2% of pollutant loads from Los Angeles River Watershed and will not achieve TMDL compliance, although several projects can make important contributions to achieve compliance. The ranking results show that the projects that treat the runoff from the largest drainage area have the greatest impact on the water quality of Los Angeles river. PMID:19092205

  18. In the trenches: lessons for scientists from California's Proposition 71 campaign

    PubMed Central

    Goldstein, Lawrence S. B.

    2011-01-01

    I describe a number of valuable lessons I learned from participating in California's Proposition 71 effort about the role that scientists and rigorous scientific advice can play in a public political process. I describe how scientists can provide valuable information and advice and how they can also gain a great deal from the experience that is valuable to a practicing research scientist. Finally, I argue that in the future, building similar broad coalitions to support biomedical and other areas of scientific research will be essential to protect publicly funded science. Thus, a key lesson from the Proposition 71 experience is that engagement of scientists with diverse nonscientific groups can make a big difference and that scientists must actively engage with the public in the future if we are to contribute robustly to the medical and economic health of our communities. PMID:22039069

  19. Framework for Evaluating the Total Value Proposition of Clean Energy Technologies

    SciTech Connect

    Pater, J. E.

    2006-02-01

    Conventional valuation techniques fail to include many of the financial advantages of clean energy technologies. By omitting benefits associated with risk management, emissions reductions, policy incentives, resource use, corporate social responsibility, and societal economic benefits, investors and firms sacrifice opportunities for new revenue streams and avoided costs. In an effort to identify some of these externalities, this analysis develops a total value proposition for clean energy technologies. It incorporates a series of values under each of the above categories, describing the opportunities for recapturing investments throughout the value chain. The framework may be used to create comparable value propositions for clean energy technologies supporting investment decisions, project siting, and marketing strategies. It can also be useful in policy-making decisions.

  20. Looking to the future of new media in health marketing: deriving propositions based on traditional theories.

    PubMed

    Della, Lindsay J; Eroglu, Dogan; Bernhardt, Jay M; Edgerton, Erin; Nall, Janice

    2008-01-01

    Market trend data show that the media marketplace continues to rapidly evolve. Recent research shows that substantial portions of the U.S. media population are "new media" users. Today, more than ever before, media consumers are exposed to multiple media at the same point in time, encouraged to participate in media content generation, and challenged to learn, access, and use the new media that are continually entering the market. These media trends have strong implications for how consumers of health information access, process, and retain health-related knowledge. In this article we review traditional information processing models and theories of interpersonal and mass media access and consumption. We make several theory-based propositions for how traditional information processing and media consumption concepts will function as new media usage continues to increase. These propositions are supported by new media usage data from the Centers for Disease Control and Prevention's entry into the new media market (e.g., podcasting, virtual events, blogging, and webinars). Based on these propositions, we conclude by presenting both opportunities and challenges that public health communicators and marketers will face in the future.

  1. Propositions of Schroedinger and Dyson: Implications for program development in secondary school biology

    NASA Astrophysics Data System (ADS)

    Kaiser-Antonowich, Roxanne

    The purpose of this study is to ascertain whether there is a linkage between the special case of New Jersey Core Curriculum Content Standards for Science as they represent biology, and the propositions of Schrodinger and Dyson. The aim of the study is to derive implications for program development in secondary school biology. Critical review reveals that the New Jersey Core Curriculum Content Standards for Science do not provide linkage to biology and the propositions of Erwin Schrodinger and Freeman Dyson. If life is characterized by replication and metabolism, then Schrodinger and Dyson present a plausible argument toward describing life as reciprocal forms and functions that characterize a living system. Examination revealed that Schrodinger, in stating that life can be characterized by the processes of replication and metabolism, emphasized replication and virtually ignored metabolism. Dyson also acknowledges the relationship of metabolism to replication. Examination of Dyson revealed that rather than describing metabolism as a characterization of life, he advances the origin of metabolism and its connection to the origin of life. If metabolism and replication characterize life and if the origin of life is within the domain of biology, then Schrodinger's and Dyson's propositions are central to the characterization of biology. If program development for secondary school biology requires accurate description of its domain, then it is necessary to acknowledge the complexity of life forms. There is as yet no universally accepted general description of life and no reasonable consensus for something to be termed living. If the conditions for something to be termed living are the capacity to reproduce self as maintained by Schrodinger, and the capacity for self-organization preserved through natural selection as proposed by Dyson, then these conditions form the basis for program development.

  2. If the real world were irrelevant, so to speak: The role of propositional truth-value in counterfactual sentence comprehension.

    PubMed

    Nieuwland, Mante S; Martin, Andrea E

    2012-01-01

    Propositional truth-value can be a defining feature of a sentence's relevance to the unfolding discourse, and establishing propositional truth-value in context can be key to successful interpretation. In the current study, we investigate its role in the comprehension of counterfactual conditionals, which describe imaginary consequences of hypothetical events, and are thought to require keeping in mind both what is true and what is false. Pre-stored real-world knowledge may therefore intrude upon and delay counterfactual comprehension, which is predicted by some accounts of discourse comprehension, and has been observed during online comprehension. The impact of propositional truth-value may thus be delayed in counterfactual conditionals, as also claimed for sentences containing other types of logical operators (e.g., negation, scalar quantifiers). In an event-related potential (ERP) experiment, we investigated the impact of propositional truth-value when described consequences are both true and predictable given the counterfactual premise. False words elicited larger N400 ERPs than true words, in negated counterfactual sentences (e.g., "If N.A.S.A. had not developed its Apollo Project, the first country to land on the moon would have been Russia/America") and real-world sentences (e.g., "Because N.A.S.A. developed its Apollo Project, the first country to land on the moon was America/Russia") alike. These indistinguishable N400 effects of propositional truth-value, elicited by opposite word pairs, argue against disruptions by real-world knowledge during counterfactual comprehension, and suggest that incoming words are mapped onto the counterfactual context without any delay. Thus, provided a sufficiently constraining context, propositional truth-value rapidly impacts ongoing semantic processing, be the proposition factual or counterfactual.

  3. If the real world were irrelevant, so to speak: The role of propositional truth-value in counterfactual sentence comprehension.

    PubMed

    Nieuwland, Mante S; Martin, Andrea E

    2012-01-01

    Propositional truth-value can be a defining feature of a sentence's relevance to the unfolding discourse, and establishing propositional truth-value in context can be key to successful interpretation. In the current study, we investigate its role in the comprehension of counterfactual conditionals, which describe imaginary consequences of hypothetical events, and are thought to require keeping in mind both what is true and what is false. Pre-stored real-world knowledge may therefore intrude upon and delay counterfactual comprehension, which is predicted by some accounts of discourse comprehension, and has been observed during online comprehension. The impact of propositional truth-value may thus be delayed in counterfactual conditionals, as also claimed for sentences containing other types of logical operators (e.g., negation, scalar quantifiers). In an event-related potential (ERP) experiment, we investigated the impact of propositional truth-value when described consequences are both true and predictable given the counterfactual premise. False words elicited larger N400 ERPs than true words, in negated counterfactual sentences (e.g., "If N.A.S.A. had not developed its Apollo Project, the first country to land on the moon would have been Russia/America") and real-world sentences (e.g., "Because N.A.S.A. developed its Apollo Project, the first country to land on the moon was America/Russia") alike. These indistinguishable N400 effects of propositional truth-value, elicited by opposite word pairs, argue against disruptions by real-world knowledge during counterfactual comprehension, and suggest that incoming words are mapped onto the counterfactual context without any delay. Thus, provided a sufficiently constraining context, propositional truth-value rapidly impacts ongoing semantic processing, be the proposition factual or counterfactual. PMID:21962826

  4. Plug-In Hybrid Electric Vehicle Value Proposition Study: Interim Report: Phase I Scenario Evaluation

    SciTech Connect

    Sikes, Karen R; Markel, Lawrence C; Hadley, Stanton W; Hinds, Shaun; DeVault, Robert C

    2009-01-01

    Plug-in hybrid electric vehicles (PHEVs) offer significant improvements in fuel economy, convenient low-cost recharging capabilities, potential environmental benefits, and decreased reliance on imported petroleum. However, the cost associated with new components (e.g., advanced batteries) to be introduced in these vehicles will likely result in a price premium to the consumer. This study aims to overcome this market barrier by identifying and evaluating value propositions that will increase the qualitative value and/or decrease the overall cost of ownership relative to the competing conventional vehicles and hybrid electric vehicles (HEVs) of 2030 During this initial phase of this study, business scenarios were developed based on economic advantages that either increase the consumer value or reduce the consumer cost of PHEVs to assure a sustainable market that can thrive without the aid of state and Federal incentives or subsidies. Once the characteristics of a thriving PHEV market have been defined for this timeframe, market introduction steps, such as supportive policies, regulations and temporary incentives, needed to reach this level of sustainability will be determined. PHEVs have gained interest over the past decade for several reasons, including their high fuel economy, convenient low-cost recharging capabilities, potential environmental benefits and reduced use of imported petroleum, potentially contributing to President Bush's goal of a 20% reduction in gasoline use in ten years, or 'Twenty in Ten'. PHEVs and energy storage from advanced batteries have also been suggested as enabling technologies to improve the reliability and efficiency of the electric power grid. However, PHEVs will likely cost significantly more to purchase than conventional or other hybrid electric vehicles (HEVs), in large part because of the cost of batteries. Despite the potential long-term savings to consumers and value to stakeholders, the initial cost of PHEVs presents a major

  5. Water quality improvement policies: lessons learned from the implementation of Proposition O in Los Angeles, California.

    PubMed

    Park, Mi-Hyun; Stenstrom, Michael; Pincetl, Stephanie

    2009-03-01

    This article evaluates the implementation of Proposition O, a stormwater cleanup measure, in Los Angeles, California. The measure was intended to create new funding to help the city comply with the Total Maximum Daily Load requirements under the federal Clean Water Act. Funding water quality objectives through a bond measure was necessary because the city had insufficient revenues to deploy new projects in its budget. The bond initiative required a supermajority vote (two-thirds of the voters), hence the public had to be convinced that such funding both was necessary and would be effective. The bond act language included project solicitation from the public, as well as multiple benefit objectives. Accordingly, nonprofit organizations mobilized to present projects that included creating new parks, using schoolyards for flood control and groundwater recharge, and replacing parking lots with permeable surfaces, among others. Yet few, if any, of these projects were retained for funding, as the city itself also had a list of priorities and higher technical expertise in justifying them as delivering water quality improvements. Our case study of the implementation of Proposition O points to the potentially different priorities for the renovation of urban infrastructure that are held by nonprofit organizations and city agencies and the importance of structuring public processes clearly so that there are no misimpressions about funding and implementation responsibilities that can lead to disillusionment with government, especially under conditions of fiscal constraints. PMID:19184186

  6. Health care competition, strategic mission, and patient satisfaction: research model and propositions

    PubMed Central

    Rivers, Patrick A.; Glover, Saundra H.

    2010-01-01

    Purpose In all industries, competition among businesses has long been encouraged as a mechanism to increase value for patients. In other words, competition ensures the provision of better products and services to satisfy the needs of customers This paper aims to develop a model that can be used to empirically investigate a number of complex issues and relationships associated with competition in the health care industry. Design/methodology/approach A literature review was conducted. A total of 50 items of literature related to the subject were reviewed.. Various perspectives of competition, the nature of service quality, health system costs, and patient satisfaction in health care are examined Findings A model of the relationship among these variables is developed. The model depicts patient satisfaction as an outcome measure directly dependent on competition. Quality of care and health care systems costs, while also directly dependent on the strategic mission and goals, are considered as determinants of customer satisfaction as well. The model is discussed in the light of propositions for empirical research. Practical implications Empirical studies based on the model proposed in this paper should help identify areas with significant impact on patient satisfaction while maintaining high quality of service at lower costs in a competitive environment. Originality/value The authors develop a research model which included propositions to examine the complex issues of competition in the health care industry. PMID:19579575

  7. Water quality improvement policies: lessons learned from the implementation of Proposition O in Los Angeles, California.

    PubMed

    Park, Mi-Hyun; Stenstrom, Michael; Pincetl, Stephanie

    2009-03-01

    This article evaluates the implementation of Proposition O, a stormwater cleanup measure, in Los Angeles, California. The measure was intended to create new funding to help the city comply with the Total Maximum Daily Load requirements under the federal Clean Water Act. Funding water quality objectives through a bond measure was necessary because the city had insufficient revenues to deploy new projects in its budget. The bond initiative required a supermajority vote (two-thirds of the voters), hence the public had to be convinced that such funding both was necessary and would be effective. The bond act language included project solicitation from the public, as well as multiple benefit objectives. Accordingly, nonprofit organizations mobilized to present projects that included creating new parks, using schoolyards for flood control and groundwater recharge, and replacing parking lots with permeable surfaces, among others. Yet few, if any, of these projects were retained for funding, as the city itself also had a list of priorities and higher technical expertise in justifying them as delivering water quality improvements. Our case study of the implementation of Proposition O points to the potentially different priorities for the renovation of urban infrastructure that are held by nonprofit organizations and city agencies and the importance of structuring public processes clearly so that there are no misimpressions about funding and implementation responsibilities that can lead to disillusionment with government, especially under conditions of fiscal constraints.

  8. Propositional idea density in older men's written language: findings from the HIMS study using computerised analysis.

    PubMed

    Spencer, Elizabeth; Ferguson, Alison; Craig, Hugh; Colyvas, Kim; Hankey, Graeme J; Flicker, Leon

    2015-02-01

    Decline in linguistic function has been associated with decline in cognitive function in previous research. This research investigated the informativeness of written language samples of Australian men from the Health in Men's Study (HIMS) aged from 76 to 93 years using the Computerised Propositional Idea Density Rater (CPIDR 5.1). In total, 60,255 words in 1147 comments were analysed using a linear-mixed model for statistical analysis. Results indicated no relationship with education level (p = 0.79). Participants for whom English was not their first learnt language showed Propositional Idea Density (PD) scores slightly lower (0.018 per 1 word). Mean PD per 1 word for those for whom English was their first language for comments below 60 words was 0.494 and above 60 words 0.526. Text length was found to have an effect (p = <0.0001). The mean PD was higher than previously reported for men and lower than previously reported for a similar cohort for Australian women.

  9. Water Quality Improvement Policies: Lessons Learned from the Implementation of Proposition O in Los Angeles, California

    NASA Astrophysics Data System (ADS)

    Park, Mi-Hyun; Stenstrom, Michael; Pincetl, Stephanie

    2009-03-01

    This article evaluates the implementation of Proposition O, a stormwater cleanup measure, in Los Angeles, California. The measure was intended to create new funding to help the city comply with the Total Maximum Daily Load requirements under the federal Clean Water Act. Funding water quality objectives through a bond measure was necessary because the city had insufficient revenues to deploy new projects in its budget. The bond initiative required a supermajority vote (two-thirds of the voters), hence the public had to be convinced that such funding both was necessary and would be effective. The bond act language included project solicitation from the public, as well as multiple benefit objectives. Accordingly, nonprofit organizations mobilized to present projects that included creating new parks, using schoolyards for flood control and groundwater recharge, and replacing parking lots with permeable surfaces, among others. Yet few, if any, of these projects were retained for funding, as the city itself also had a list of priorities and higher technical expertise in justifying them as delivering water quality improvements. Our case study of the implementation of Proposition O points to the potentially different priorities for the renovation of urban infrastructure that are held by nonprofit organizations and city agencies and the importance of structuring public processes clearly so that there are no misimpressions about funding and implementation responsibilities that can lead to disillusionment with government, especially under conditions of fiscal constraints.

  10. A study of anomia: evidence for a distinction between nominal and propositional language.

    PubMed

    Breen, K; Warrington, E K

    1994-06-01

    We describe our investigations of the word retrieval abilities of a patient (NOR) with a very severe anomia. NOR had the greatest difficulty naming even very common objects to confrontation yet his word comprehension, word repetition and reading skills were intact. We documented the efficacy of different types of cues for name retrieval. Phonological and semantic cues were either ineffective or had a minor effect. By contrast a sentence frame even a low probability sentence frame (e.g. I went to the shop to buy a ...?) had a very significant facilitatory effect for object naming. In a series of experiments we explored the basis of this facilitation. It was shown that neither a picture frame, an associated verb, nor a syntactically correct but semantically meaningless sentence frame were effective cues. Our findings challenge the orthodox linear models of object naming. We interpret our observations in the context of Luria's distinction between nominative and propositional language. It is suggested that there may be two 'routes' to name retrieval, one that utilises a nominative system and an alternative one that utilises an on-line language processor that constructs propositional speech. It is the integrity of this latter system that could account for the facilitation of naming by a sentence frame in NOR, and also for the frequently observed phenomenon of the preservation of fluent speech in patients with a grave anomia.

  11. A Hierarchical Multi-Model Approach for Uncertainty Segregation, Prioritization and Comparative Evaluation of Competing Modeling Propositions

    NASA Astrophysics Data System (ADS)

    Tsai, F. T.; Elshall, A. S.; Hanor, J. S.

    2012-12-01

    Subsurface modeling is challenging because of many possible competing propositions for each uncertain model component. How can we judge that we are selecting the correct proposition for an uncertain model component out of numerous competing propositions? How can we bridge the gap between synthetic mental principles such as mathematical expressions on one hand, and empirical observation such as observation data on the other hand when uncertainty exists on both sides? In this study, we introduce hierarchical Bayesian model averaging (HBMA) as a multi-model (multi-proposition) framework to represent our current state of knowledge and decision for hydrogeological structure modeling. The HBMA framework allows for segregating and prioritizing different sources of uncertainty, and for comparative evaluation of competing propositions for each source of uncertainty. We applied the HBMA to a study of hydrostratigraphy and uncertainty propagation of the Southern Hills aquifer system in the Baton Rouge area, Louisiana. We used geophysical data for hydrogeological structure construction through indictor hydrostratigraphy method and used lithologic data from drillers' logs for model structure calibration. However, due to uncertainty in model data, structure and parameters, multiple possible hydrostratigraphic models were produced and calibrated. The study considered four sources of uncertainties. To evaluate mathematical structure uncertainty, the study considered three different variogram models and two geological stationarity assumptions. With respect to geological structure uncertainty, the study considered two geological structures with respect to the Denham Springs-Scotlandville fault. With respect to data uncertainty, the study considered two calibration data sets. These four sources of uncertainty with their corresponding competing modeling propositions resulted in 24 calibrated models. The results showed that by segregating different sources of uncertainty, HBMA analysis

  12. Associations and propositions: the case for a dual-process account of learning in humans.

    PubMed

    McLaren, I P L; Forrest, C L D; McLaren, R P; Jones, F W; Aitken, M R F; Mackintosh, N J

    2014-02-01

    We review evidence that supports the conclusion that people can and do learn in two distinct ways - one associative, the other propositional. No one disputes that we solve problems by testing hypotheses and inducing underlying rules, so the issue amounts to deciding whether there is evidence that we (and other animals) also rely on a simpler, associative system, that detects the frequency of occurrence of different events in our environment and the contingencies between them. There is neuroscientific evidence that associative learning occurs in at least some animals (e.g., Aplysia californica), so it must be the case that associative learning has evolved. Since both associative and propositional theories can in principle account for many instances of successful learning, the problem is then to show that there are at least some cases where the two classes of theory predict different outcomes. We offer a demonstration of cue competition effects in humans under incidental conditions as evidence against the argument that all such effects are based on cognitive inference. The latter supposition would imply that if the necessary information is unavailable to inference then no cue competition should occur. We then discuss the case of unblocking by reinforcer omission, where associative theory predicts an irrational solution to the problem, and consider the phenomenon of the Perruchet effect, in which conscious expectancy and conditioned response dissociate. Further discussion makes use of evidence that people will sometimes provide one solution to a problem when it is presented to them in summary form, and another when they are presented in rapid succession with trial-by trial information. We also demonstrate that people trained on a discrimination may show a peak shift (predicted by associative theory), but given the time and opportunity to detect the relationships between S+ and S-, show rule-based behavior instead. Finally, we conclude by presenting evidence that

  13. [Difference analysis among majors in medical parasitology exam papers by test item bank proposition].

    PubMed

    Jia, Lin-Zhi; Ya-Jun, Ma; Cao, Yi; Qian, Fen; Li, Xiang-Yu

    2012-04-30

    The quality index among "Medical Parasitology" exam papers and measured data for students in three majors from the university in 2010 were compared and analyzed. The exam papers were formed from the test item bank. The alpha reliability coefficients of the three exam papers were above 0.70. The knowledge structure and capacity structure of the exam papers were basically balanced. But the alpha reliability coefficients of the second major was the lowest, mainly due to quality of test items in the exam paper and the failure of revising the index of test item bank in time. This observation demonstrated that revising the test items and their index in the item bank according to the measured data can improve the quality of test item bank proposition and reduce the difference among exam papers.

  14. Rethinking gender and mental health: a critical analysis of three propositions.

    PubMed

    Hill, Terrence D; Needham, Belinda L

    2013-09-01

    In this paper, we critically examine three propositions that are widely (but not universally) accepted in the gender and mental health literature. First, women and men have similar or equal rates of overall psychopathology. Second, affective disorders like anxiety and depression, which are more common among women, and behavioral disorders like substance abuse and antisocial personality, which are more common among men, are functionally equivalent indicators of misery. Finally, women are more likely to respond to stressful conditions with affective disorders while men are more likely to respond to stressful conditions with behavioral disorders. Our review of previous research shows little to no consistent empirical support for any of these propositions. Results from national studies of overall psychopathology or "any disorder" are, at best, mixed and limited to a narrow range of mental health conditions. A comprehensive test of gender differences in overall psychopathology would require a systematic and exhaustive examination of gender differences across the known universe of mental health conditions, but this may be impossible to achieve due to a lack of consensus on the universe, the proliferation of diagnostic categories, and the tendency to pathologize the mental health of women. There is no empirical evidence to suggest that women substitute affective disorders for behavioral disorders or that men substitute behavioral disorders for affective disorders. There is no theory to suggest that affective and behavioral disorders should be treated as comparable indicators of misery. Some studies support the idea that women and men respond to stress in different ways, but most do not. Numerous studies show that women and men respond to stressors with higher levels of emotional distress, substance abuse, and antisocial behavior. We conclude with seven recommendations to advance theory and research and several general reflections on the sociological study of gender and

  15. Current knowledge on the genetics of autism and propositions for future research.

    PubMed

    Bourgeron, Thomas

    2016-01-01

    Autism spectrum disorders (ASD) are a heterogeneous group of neuropsychiatric disorders characterized by problems in social communication, as well as by the presence of restricted interests, stereotyped and repetitive behaviours. In the last 40years, genetic studies have provided crucial information on the causes of ASD and its diversity. In this article, I will first review the current knowledge on the genetics of ASD and then suggest three propositions to foster research in this field. Twin and familial studies estimated the heritability of ASD to be 50%. While most of the inherited part of ASD is captured by common variants, our current knowledge on the genetics of ASD comes almost exclusively from the identification of highly penetrant de novo mutations through candidate gene or whole exome/genome sequencing studies. Approximately 10% of patients with ASD, especially those with intellectual disability, are carriers of de novo copy-number (CNV) or single nucleotide variants (SNV) affecting clinically relevant genes for ASD. Given the function of these genes, it was hypothesized that abnormal synaptic plasticity and failure of neuronal/synaptic homeostasis could increase the risk of ASD. In addition to these discoveries, three propositions coming from institutions, researchers and/or communities of patients and families can be made to foster research on ASD: (i) to use more dimensional and quantitative data than diagnostic categories; (ii) to increase data sharing and research on genetic and brain diversity in human populations; (iii) to involve patients and relatives as participants for research. Hopefully, this knowledge will lead to a better diagnosis, care and integration of individuals with ASD.

  16. Propositional idea density in women's written language over the lifespan: computerized analysis.

    PubMed

    Ferguson, Alison; Spencer, Elizabeth; Craig, Hugh; Colyvas, Kim

    2014-06-01

    The informativeness of written language, as measured by Propositional Idea Density (PD), has been shown to be a sensitive predictive index of language decline with age and dementia in previous research. The present study investigated the influence of age and education on the written language of three large cohorts of women from the general community, born between 1973 and 1978, 1946-51 and 1921-26. Written texts were obtained from the Australian Longitudinal Study on Women's Health in which participants were invited to respond to an open-ended question about their health. The informativeness of written comments of 10 words or more (90% of the total number of comments) was analyzed using the Computerized Propositional Idea Density Rater 3 (CPIDR-3). Over 2.5 million words used in 37,705 written responses from 19,512 respondents were analyzed. Based on a linear mixed model approach to statistical analysis with adjustment for several factors including number of comments per respondent and number of words per comment, a small but statistically significant effect of age was identified for the older cohort with mean age 78 years. The mean PD per word for this cohort was lower than the younger and mid-aged cohorts with mean age 27 and 53 years respectively, with mean reduction in PD 95% confidence interval (CI) of .006 (.003, .008) and .009 (.008, .011) respectively. This suggests that PD for this population of women was relatively more stable over the adult lifespan than has been reported previously even in late old age. There was no statistically significant effect of education level. Computerized analyses were found to greatly facilitate the study of informativeness of this large corpus of written language. Directions for further research are discussed in relation to the need for extended investigation of the variability of the measure for potential application to the identification of acquired language pathologies.

  17. Welfare Systems, Support Networks and Subjective Well-Being among Retired Persons

    ERIC Educational Resources Information Center

    Requena, Felix

    2010-01-01

    In this article welfare systems and support networks are empirically analyzed to determine which generate the highest level of subjective well-being among retired persons. Propositions derived from support network theories and national welfare system typologies have been analyzed using causal models that indicate the influence of the various…

  18. Predicting Item Difficulty in a Reading Comprehension Test with an Artificial Neural Network.

    ERIC Educational Resources Information Center

    Perkins, Kyle; And Others

    1995-01-01

    This article reports the results of using a three-layer back propagation artificial neural network to predict item difficulty in a reading comprehension test. Three classes of variables were examined: text structure, propositional analysis, and cognitive demand. Results demonstrate that the networks can consistently predict item difficulty. (JL)

  19. Inferred Propositions and the Expression of the Evidence Relation in Natural Language Evidentiality in Central Alaskan Yup'ik Eskimo and English

    ERIC Educational Resources Information Center

    Krawczyk, Elizabeth A.

    2012-01-01

    Evidentiality has usually been defined as the grammaticalized expression of a speaker's evidence source for a proposition, where "evidence" is conceptualized as a speaker's source-type for a particular proposition (Aikhenvald 2004). How this evidence source-type and the evidential are related has yet to be formally modeled in…

  20. Treating Drug-Abusing Offenders: Initial Findings from a Five-County Study on the Impact of California's Proposition 36 on the Treatment System and Patient Outcomes

    ERIC Educational Resources Information Center

    Hser, Yih-Ing; Teruya, Cheryl; Evans, Elizabeth A.; Longshore, Douglas; Grella, Christine; Farabee, David

    2003-01-01

    Five counties (Kern, Riverside, Sacramento, San Diego, San Francisco) that demonstrate both variations and similarities in their implementation of Proposition 36 (e.g., treatment approaches, urine testing) and patient mix have been selected to participate in a study assessing how California's Proposition 36 is affecting the drug treatment system…

  1. What Is yet to Come? Three Propositions on the Future of Educational Research as a Common Good

    ERIC Educational Resources Information Center

    Decuypere, Mathias

    2015-01-01

    This paper offers some explorative notes accompanying the issues I addressed in the journal's moot, which took place at the ECER 2014 conference (Porto, September 1-5). The notes that follow are explicitly written through the eyes of an emerging researcher, and offer three propositions regarding the future of educational research. These three…

  2. Developmental and Behavioral Health Services for Children: Opportunities and Challenges for Proposition 10. Building Community Systems for Young Children.

    ERIC Educational Resources Information Center

    Wright, Kynna; Kuo, Alice; Regalado, Michael; Halfon, Neal

    As part of a series of reports designed to support the implementation of Proposition 10: The California Children and Families Act and to provide comprehensive and authoritative information on critical issues concerning young children and families in California, this report examines how child health services can be improved to support two related…

  3. Using the Implicit Association Test Does Not Rule Out an Impact of Conscious Propositional Knowledge on Evaluative Conditioning

    ERIC Educational Resources Information Center

    De Houwer, Jan

    2006-01-01

    Implicit measures such as the Implicit Association Test (OAT) have recently become popular as tools in research on evaluative conditioning. The reason is that these measures are thought to be impervious to changes in valence that are due to conscious propositional knowledge about the relation between the conditioned stimulus (CS) and the…

  4. Proposition: a personality disorder may nullify responsibility for a criminal act.

    PubMed

    Kinscherff, Robert

    2010-01-01

    This article argues in support of the proposition that "A Personality Disorder May Nullify Responsibility for a Criminal Act." Building upon research in categorical and dimensional controversies in diagnosis, neurocognitive science and the behavioral genetics of mental disorders, and difficulties in differential diagnosis and co-morbidity with personality disorders, this article holds that a per se rule barring personality diagnosis as a basis for a defense of legal insanity is scientifically and conceptually indefensible. Rather, focus should be upon the severity and impact in specific cases of any legally relevant functional deficits arising from a mental disorder (including personality disorders). Failure to do so risks potentially misleading "battles of the experts" about a defendant's diagnosis in criminal responsibility defenses and improper usurpation of the role of the legal finder of fact as mental health expert witnesses are inserted as gatekeepers indefensibly based upon diagnosis. Implications for practice and public policy are considered, including a "modest proposal" for post-trial management of defendants found not guilty by reason of insanity on the basis of functional deficits arising from personality disorder.

  5. Semantic knowledge fractionations: verbal propositions vs. perceptual input? Evidence from a child with Klinefelter syndrome.

    PubMed

    Robinson, Sally J; Temple, Christine M

    2013-04-01

    This paper addresses the relative independence of different types of lexical- and factually-based semantic knowledge in JM, a 9-year-old boy with Klinefelter syndrome (KS). JM was matched to typically developing (TD) controls on the basis of chronological age. Lexical-semantic knowledge was investigated for common noun (CN) and mathematical vocabulary items (MV). Factually-based semantic knowledge was investigated for general and number facts. For CN items, JM's lexical stores were of a normal size but the volume of correct 'sensory feature' semantic knowledge he generated within verbal item descriptions was significantly reduced. He was also significantly impaired at naming item descriptions and pictures, particularly for fruit and vegetables. There was also weak object decision for fruit and vegetables. In contrast, for MV items, JM's lexical stores were elevated, with no significant difference in the amount and type of correct semantic knowledge generated within verbal item descriptions and normal naming. JM's fact retrieval accuracy was normal for all types of factual knowledge. JM's performance indicated a dissociation between the representation of CN and MV vocabulary items during development. JM's preserved semantic knowledge of facts in the face of impaired semantic knowledge of vocabulary also suggests that factually-based semantic knowledge representation is not dependent on normal lexical-semantic knowledge during development. These findings are discussed in relation to the emergence of distinct semantic knowledge representations during development, due to differing degrees of dependency upon the acquisition and representation of semantic knowledge from verbal propositions and perceptual input.

  6. Working memory, text comprehension, and propositional reasoning: a new Semantic Anaphora WM test.

    PubMed

    Carriedo, Nuria; Elosúa, M Rosa; García-Madruga, Juan A

    2011-05-01

    The aim of this study was to present a new working memory test following the line of work started by García-Madruga et al. (2007) and to examine its relation to reading comprehension and propositional reasoning measures. In that study we designed a new working memory span test--based on Daneman & Carpenter's (1980) Reading Span Test (RST)--in which the processing task called for an inferential decision--to resolve a pronominal anaphora based on Morpho-Syntactic cues and had people recall the result of this inference. In the current study, besides the RST and the Morpho-Syntactic Anaphora test, we presented a new Semantic Anaphora measure. In order to check the validity of this new Working Memory (WM) task, we used the same reasoning task used in the previous study as well as a new reading comprehension test. The results show the tight relationship amongst working memory, reading comprehension and reasoning, and confirm the validity of the new WM measure.

  7. An analysis of the validity and utility of the proximon proposition.

    PubMed

    Vey, Gregory; Charles, Trevor C

    2016-03-01

    The utilization of metagenomic functional interactions represents a key technique for metagenomic functional annotation efforts. By definition, metagenomic operons represent such interactions, but many operon predictions protocols rely on information about orthology and/or gene function that is frequently unavailable for metagenomic genes. Recently, the concept of the metagenomic proximon was proposed for use in metagenomic scenarios where supplemental information is sparse. In this paper, we examine the validity and utility of the proximon proposition by measuring the extent to which proximons emulate actual operons. Using the Escherichia coli K-12 genome, we compare proximons and operons from the same genome and observe the configurations and cardinalities among their corresponding mappings. The results demonstrate that the vast majority of proximons map discretely to a single operon in a conservative fashion where a typical proximon is synonymous to an equivalent or truncated operon. However, a large proportion of operons had no corresponding mappings to any proximon. Various perspectives of operon and proximon intersection are discussed, along with the potential limitations for proximon detection and usage. PMID:26839085

  8. A protocol proposition of cell therapy for the treatment of chronic obstructive pulmonary disease.

    PubMed

    Ribeiro-Paes, J T; Stessuk, T; Marcelino, M; Faria, C; Marinelli, T; Ribeiro-Paes, M J

    2014-01-01

    The main feature of pulmonary emphysema is airflow obstruction resulting from the destruction of the alveolar walls distal to the terminal bronchioles. Existing clinical approaches have improved and extended the quality of life of emphysema patients. However, no treatment currently exists that can change the disease course and cure the patient. The different therapeutic approaches that are available aim to increase survival and/or enhance the quality of life of emphysema patients. In this context, cell therapy is a promising therapeutic approach with great potential for degenerative pulmonary diseases. In this protocol proposition, all patients will be submitted to laboratory tests, such as evaluation of heart and lung function and routine examinations. Stem cells will be harvested by means of 10 punctures on each anterior iliac crest, collecting a total volume of 200mL bone marrow. After preparation, separation, counting and labeling (optional) of the mononuclear cells, the patients will receive an intravenous infusion from the pool of Bone Marrow Mononuclear Cells (BMMC). This article proposes a rational and safe clinical cellular therapy protocol which has the potential for developing new projects and can serve as a methodological reference for formulating clinical application protocols related to the use of cellular therapy in COPD. This study protocol was submitted and approved by the Brazilian National Committee of Ethics in Research (CONEP - Brazil) registration number 14764. It is also registered in ClinicalTrials.gov (NCT01110252).

  9. Another Scale for the Assessment of Facial Paralysis? ADS Scale: Our Proposition, How to Use It

    PubMed Central

    2015-01-01

    Introduction Several authors in the years propose different methods to evaluate areas and specific movement’s disease in patient affected by facial palsy. Despite these efforts the House Brackmann is anyway the most used assessment in medical community. Aim The aims of our study is the proposition and assessing a new rating Arianna Disease Scale (ADS) for the clinical evaluation of facial paralysis. Materials and Methods Sixty patients affected by unilateral facial Bell paralysis were enrolled in a prospective study from 2012 to 2014. Their facial nerve function was evaluated with our assessment analysing facial district divided in upper, middle and lower third. We analysed different facial expressions. Each movement corresponded to the action of different muscles. The action of each muscle was scored from 0 to 1, with 0 corresponding from complete flaccid paralysis to muscle’s normal function ending with a score of 1. Synkinesis was considered and evaluated also in the scale with a fixed 0.5 score. Our results considered ease and speed of evaluation of the assessment, the accuracy of muscle deficit and the ability to calculate synkinesis using a score. Results All the three observers agreed 100% in the highest degree of deficit. We found some discrepancies in intermediate score with 92% agreement in upper face, 87% in middle and 80% in lower face, where there were more muscles involved in movements. Conclusion Our scale had some limitations linked to the small group of patients evaluated and we had a little difficulty understanding the intermediate score of 0.3 and 0.7. However, this was an accurate tool to quickly evaluate facial nerve function. This has potential as an alternative scale to and to diagnose facial nerve disorders. PMID:26814596

  10. Plug-in Hybrid Electric Vehicle Value Proposition Study - Final Report

    SciTech Connect

    Sikes, Karen; Hadley, Stanton W; McGill, Ralph N; Cleary, Timothy

    2010-07-01

    PHEVs have been the subject of growing interest in recent years because of their potential for reduced operating costs, oil displacement, national security, and environmental benefits. Despite the potential long-term savings to consumers and value to stakeholders, the initial cost of PHEVs presents a major market barrier to their widespread commercialization. The study Objectives are: (1) To identify and evaluate value-added propositions for PHEVs that will help overcome the initial price premium relative to comparable ICEs and HEVs and (2) to assess other non-monetary benefits and barriers associated with an emerging PHEV fleet, including environmental, societal, and grid impacts. Study results indicate that a single PHEV-30 on the road in 2030 will: (1) Consume 65% and 75% less gasoline than a comparable HEV and ICE, respectively; (2) Displace 7.25 and 4.25 barrels of imported oil each year if substituted for equivalent ICEs and HEVs, respectively, assuming 60% of the nation's oil consumed is imported; (3) Reduce net ownership cost over 10 years by 8-10% relative to a comparable ICE and be highly cost competitive with a comparable HEV; (4) Use 18-22% less total W2W energy than a comparable ICE, but 8-13% more than a comparable HEV (assuming a 70/30 split of E10 and E85 use in 2030); and (5) Emit 10% less W2W CO{sub 2} than equivalent ICEs in southern California and emits 13% more W2W CO{sub 2} than equivalent ICEs in the ECAR region. This also assumes a 70/30 split of E10 and E85 use in 2030. PHEVs and other plug-in vehicles on the road in 2030 may offer many valuable benefits to utilities, business owners, individual consumers, and society as a whole by: (1) Promoting national energy security by displacing large volumes of imported oil; (2) Supporting a secure economy through the expansion of domestic vehicle and component manufacturing; (3) Offsetting the vehicle's initial price premium with lifetime operating cost savings (e.g., lower fuel and maintenance

  11. An Examination of Native and Immigrant Students' Social Networking Using the College Search and Selection Process

    ERIC Educational Resources Information Center

    Neimeyer, Bruce Carlton

    2009-01-01

    This dissertation explores the use of formal and informal networks through cyber- and traditional communication methods in the college search and selection process by native and immigrant students to examine various postulates and propositions of social capital theory. In addition, the analysis of cybernetworks used by disadvantaged, college bound…

  12. TOWARDS AN AUTOMATED TOOL FOR CHANNEL-NETWORK CHARACTERIZATIONS, MODELING, AND ASSESSMENT

    EPA Science Inventory

    Detailed characterization of channel networks for hydrologic and geomorphic models has traditionally been a difficult and expensive proposition, and lack of information has thus been a common limitation of modeling efforts. With the advent of datasets derived from high-resolutio...

  13. Environmental Uncertainty and Communication Network Complexity: A Cross-System, Cross-Cultural Test.

    ERIC Educational Resources Information Center

    Danowski, James

    An infographic model is proposed to account for the operation of systems within their information environments. Infographics is a communication paradigm used to indicate the clustering of information processing variables in communication systems. Four propositions concerning environmental uncertainty and internal communication network complexity,…

  14. Knowledge Networking: A Dilemma in Building Social Capital through Nonformal Education

    ERIC Educational Resources Information Center

    Shrestha, Mona; Wilson, Steve; Singh, Michael

    2008-01-01

    This article reports the results of an inquiry into the embeddedness of nonformal education (NFE) in the work of knowledge service providers, analyzing the dilemmas they experience in their operations around a public housing precinct. It explores the proposition that the networking of NFE providers is a mechanism by which a fragmented community…

  15. Daring to Marry: Marriage Equality Activism After Proposition 8 as Challenge to the Assimilationist/Radical Binary in Queer Studies.

    PubMed

    Weber, Shannon

    2015-01-01

    I analyze three case studies of marriage equality activism and marriage equality-based groups after the passage of Proposition 8 in California. Evaluating the JoinTheImpact protests of 2008, the LGBTQ rights group GetEQUAL, and the group One Struggle One Fight, I argue that these groups revise queer theoretical arguments about marriage equality activism as by definition assimilationist, homonormative, and single-issue. In contrast to such claims, the cases studied here provide a snapshot of heterogeneous, intersectional, and coalition-based social justice work in which creative methods of protest, including direct action and flash mobs, are deployed in militant ways for marriage rights and beyond.

  16. Value Proposition for High Lifetime (p-type) and Thin Silicon Materials in Solar PV Applications: Preprint

    SciTech Connect

    Goodrich, A.; Woodhouse, M.; Hacke, P.

    2012-06-01

    Most silicon PV road maps forecast a continued reduction in wafer thickness, despite rapid declines in the primary incentive for doing so -- polysilicon feedstock price. Another common feature of most silicon-technology forecasts is the quest for ever-higher device performance at the lowest possible costs. The authors present data from device-performance and manufacturing- and system-installation cost models to quantitatively establish the incentives for manufacturers to pursue advanced (thin) wafer and (high efficiency) cell technologies, in an age of reduced feedstock prices. This analysis exhaustively considers the value proposition for high lifetime (p-type) silicon materials across the entire c-Si PV supply chain.

  17. Fuzzy propositions weighted by veracities or how to relate fuzzy logic and probability theory for segmentation of ultrasound images

    NASA Astrophysics Data System (ADS)

    Debon, Renaud; Solaiman, Basel; Cauvin, Jean-Michel; Robaszkiewicz, Michel; Roux, Christian

    2002-03-01

    In medical imaging, and more generally in medical information, researches go towards fusion systems. Nowadays, the steps of information source definition, the pertinent data extraction and the fusion need to be conducted as a whole. In this work, our interest is related to the esophagus wall segmentation from ultrasound images sequences. We aim to elaborate a general methodology of data mining that coherently links works on data selection and fusion architectures, in order to extract useful information from raw data and to integrate efficiently the physician a prior. In the presented method, based on fuzzy logic, some fuzzy propositions are defined using physicians a prior knowledge. The use of probabilistic distributions, estimated thanks to a learning base of pathologic and non-pathologic cases, enables the veracity of these propositions to be qualified. This promising idea enables information to be managed through the consideration of both information imprecision and uncertainty. In the same time, the obtained benefit, when a prior knowledge source is injected in a fusion based decision system, can be quantified. By considering that, the fuzzyfication stage is optimized relatively to a given criteria using a genetic algorithm. By this manner, fuzzy sets corresponding to the physicians ambiguous a prior are defined objectively. At this level, we successively compare performances obtained when fuzzy functions are defined empirically and when they are optimized. We conclude this paper with the first results on esophagus wall segmentation and outline some further works.

  18. The implementation of California's tobacco tax initiative: the critical role of outsider strategies in protecting Proposition 99.

    PubMed

    Balbach, E D; Traynor, M P; Glantz, S A

    2000-08-01

    Enacted in 1988, Proposition 99 increased California's cigarette tax by 25 cents per pack and allocated a minimum of 20 percent of the revenues to fund antitobacco education. Tobacco control advocates had used an initiative to secure the tax increase because the legislature had not increased the tobacco tax since 1967, even though public opinion polls showed that the tax was politically popular. Advocates, however, then had to return to the legislature to negotiate implementing legislation. Between 1989 and 1996, the legislature underfunded the Proposition 99 Health Education programs by over $273 million. This underfunding occurred because the public health groups failed to exercise power, ideas, and the leadership needed for legislative success. Even successful litigation against the governor failed to restore the programs. In July 1996, however, the underexpenditures stopped because the issue of the diversions received significant media and public attention. The tobacco control groups used a variety of outsider strategies, including paid advertising, free media, and a grassroots campaign, and the leadership of these groups, in addition to the lobbyists, got involved in the campaign to secure implementing legislation. Without ongoing public pressure, it is likely that policy changes created by tobacco tax initiatives will dissipate into something acceptable to powerful insider interests, such as the tobacco and medical service provider industries.

  19. Daring to Marry: Marriage Equality Activism After Proposition 8 as Challenge to the Assimilationist/Radical Binary in Queer Studies.

    PubMed

    Weber, Shannon

    2015-01-01

    I analyze three case studies of marriage equality activism and marriage equality-based groups after the passage of Proposition 8 in California. Evaluating the JoinTheImpact protests of 2008, the LGBTQ rights group GetEQUAL, and the group One Struggle One Fight, I argue that these groups revise queer theoretical arguments about marriage equality activism as by definition assimilationist, homonormative, and single-issue. In contrast to such claims, the cases studied here provide a snapshot of heterogeneous, intersectional, and coalition-based social justice work in which creative methods of protest, including direct action and flash mobs, are deployed in militant ways for marriage rights and beyond. PMID:25848693

  20. Comparative Effectiveness of California’s Proposition 36 and Drug Court Programs Before and After Propensity Score Matching

    PubMed Central

    Evans, Elizabeth; Li, Libo; Urada, Darren; Anglin, M. Douglas

    2013-01-01

    California’s voter-initiated Proposition 36 (Prop 36) program is often unfavorably compared to drug courts, but little is empirically known about the comparative effectiveness of the two approaches. Using statewide administrative data, analyses were conducted on all Prop 36 and drug court offenders with official records of arrest and drug treatment. Propensity score matching was used to create equivalent groups, enabling comparisons of success at treatment discharge, recidivism over 12 months post-treatment entry, and magnitude of behavioral changes. Significant behavioral improvements occurred for both Prop 36 and drug court offenders, but while more Prop 36 offenders were successful at discharge, more recidivated over 12 months. Core programmatic differences likely contributed to differences in outcomes. Policy implications are discussed. PMID:25342859

  1. Evaluating the value proposition for improving vaccine thermostability to increase vaccine impact in low and middle-income countries.

    PubMed

    Karp, Christopher L; Lans, Deborah; Esparza, José; Edson, Eleanore B; Owen, Katey E; Wilson, Christopher B; Heaton, Penny M; Levine, Orin S; Rao, Raja

    2015-07-01

    The need to keep vaccines cold in the face of high ambient temperatures and unreliable access to electricity is a challenge that limits vaccine coverage in low and middle-income countries (LMICs). Greater vaccine thermostability is generally touted as the obvious solution. Despite conventional wisdom, comprehensive analysis of the value proposition for increasing vaccine thermostability has been lacking. Further, while significant investments have been made in increasing vaccine thermostability in recent years, no vaccine products have been commercialized as a result. We analyzed the value proposition for increasing vaccine thermostability, grounding the analysis in specific vaccine use cases (e.g., use in routine immunization [RI] programs, or in campaigns) and in the broader context of cold chain technology and country level supply chain system design. The results were often surprising. For example, cold chain costs actually represent a relatively small fraction of total vaccine delivery system costs. Further, there are critical, vaccine use case-specific temporal thresholds that need to be overcome for significant benefits to be reaped from increasing vaccine thermostability. We present a number of recommendations deriving from this analysis that suggest a rational path toward unlocking the value (maximizing coverage, minimizing total system costs) of increased vaccine thermostability, including: (1) the full range of thermostability of existing vaccines should be defined and included in their labels; (2) for new vaccines, thermostability goals should be addressed up-front at the level of the target product profile; (3) improving cold chain infrastructure and supply chain system design is likely to have the largest impact on total system costs and coverage in the short term-and will influence the degree of thermostability required in the future; (4) in the long term, there remains value in monitoring the emergence of disruptive technologies that could remove the

  2. Effects of the Implementation of Proposition 227 on the Education of English Learners, K-12: Findings from a Five-Year Evaluation. Final Report for AB 56 and AB 1116

    ERIC Educational Resources Information Center

    Parrish, Thomas B.; Merickel, Amy; Perez, Maria; Linquanti, Robert; Socias, Miguel; Spain, Angeline; Speroni, Cecilia; Esra, Phil; Brock, Leslie; Delancey, Danielle

    2006-01-01

    In June of 1998, Proposition 227 was passed by 61 percent of the California electorate. The initiative was intended to significantly alter the ways in which the state's English learners (ELs) are taught. Proposition 227 requires that ELs be taught "overwhelmingly in English" through sheltered/structured English immersion (SEI) programs during "a…

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

    NASA Astrophysics Data System (ADS)

    Heuer, Mark Alan

    2001-12-01

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

  4. On the November Ballot--Proposition 4: Creating More Tier-One Universities in Texas. Policy Page. No. 09-415

    ERIC Educational Resources Information Center

    Center for Public Policy Priorities, 2009

    2009-01-01

    The most important natural resource Texas has is Texans. Unfortunately, the state suffers from a "brain drain" as many of the best and brightest students leave to further their education. A contributing cause is a lack of "tier one" universities in Texas. Proposition 4 (a constitutional amendment to create a National Research University Fund to…

  5. Promising practices for delivery of court-supervised substance abuse treatment: Perspectives from six high-performing California counties operating Proposition 36

    PubMed Central

    Evans, Elizabeth; Anglin, M. Douglas; Urada, Darren; Yang, Joy

    2010-01-01

    Operative for nearly a decade, California's voter-initiated Proposition 36 program offers many offenders community-based substance abuse treatment in lieu of likely incarceration. Research has documented program successes and plans for replication have proliferated, yet very little is known about how the Proposition 36 program works or practices for achieving optimal program outcomes. In this article, we identify policies and practices that key stakeholders perceive to be most responsible for the successful delivery of court-supervised substance abuse treatment to offenders under Proposition 36. Data was collected via focus groups conducted with 59 county stakeholders in six high-performing counties during 2009. Discussion was informed by seven empirical indicators of program performance and outcomes and was focused on identifying and describing elements contributing to success. Program success was primarily attributed to four strategies, those that: (1) fostered program engagement, monitored participant progress, and sustained cooperation among participants; (2) cultivated buy-in among key stakeholders; (3) capitalized on the role of the court and the judge; and (4) created a setting which promoted a high-quality treatment system, utilization of existing resources, and broad financial and political support for the program. Goals and practices for implementing each strategy are discussed. Findings provide a “promising practices” resource for Proposition 36 program evaluation and improvement and inform the design and study of other similar types of collaborative justice treatment efforts. PMID:20965568

  6. Perceived Quality of Private Education and Fears of Stratification: Investigating the Propositions of Human Capital Theory by Exploring the Case of Colombia

    ERIC Educational Resources Information Center

    Nel Páez, Pedro; Teelken, Christine

    2016-01-01

    The purpose of this paper is to discuss the recent developments in the higher education system of Colombia in order to illustrate how these encourage stratification between (types of) universities and their students. We do so by discussing propositions generated by human capital theory and apply them to the experiences of students and graduates…

  7. [For a coordination of the supportive care for people affected by severe illnesses: proposition of organization in the public and private health care centres].

    PubMed

    Krakowski, Ivan; Boureau, François; Bugat, Roland; Chassignol, Laurent; Colombat, Philippe; Copel, Laure; d'Hérouville, Daniel; Filbet, Marylène; Laurent, Bernard; Memran, Nadine; Meynadier, Jacques; Parmentier, Gérard; Poulain, Philippe; Saltel, Pierre; Serin, Daniel; Wagner, Jean-Philippe

    2004-05-01

    The concept of continuous and global care is acknowledged today by all as inherent to modern medicine. A working group gathered to propose models for the coordination of supportive care for all severe illnesses in the various private and public health care centres. The supportive care are defined as: "all care and supports necessary for ill people, at the same time as specific treatments, along all severe illnesses". This definition is inspired by that of "supportive care" given in 1990 by the MASCC (Multinational Association for Supportive Care in Cancer): "The total medical, nursing and psychosocial help which the patients need besides the specific treatment". It integrates as much the field of cure with possible after-effects as that of palliative care, the definition of which is clarified (initial and terminal palliative phases). Such a coordination is justified by the pluridisciplinarity and hyperspecialisation of the professionals, by a poor communication between the teams, by the administrative difficulties encountered by the teams participating in the supportive care. The working group insists on the fact that the supportive care is not a new speciality. He proposes the creation of units. departments or pole of responsibility of supportive care with a "basic coordination" involving the activities of chronic pain, palliative care, psycho-oncology, and social care. This coordination can be extended, according to the "history" and missions of health care centres. Service done with the implementation of a "unique counter" for the patients and the teams is an important point. The structure has to comply with the terms and conditions of contract (Consultation, Unit or Centre of chronic pain, structures of palliative care, of psycho-oncology, of nutrition, of social care). A common technical organization is one of the interests. The structure has to set up strong links with the private practitioners, the networks, the home medical care (HAD) and the nurses

  8. [For a coordination of the supportive care for people affected by severe illnesses: proposition of organization in the public and private health care centres].

    PubMed

    Krakowski, Ivan; Boureau, François; Bugat, Roland; Chassignol, Laurent; Colombat, Philippe; Copel, Laure; d'Hérouville, Daniel; Filbet, Marylène; Laurent, Bernard; Memran, Nadine; Meynadier, Jacques; Parmentier, Gérard; Poulain, Philippe; Saltel, Pierre; Serin, Daniel; Wagner, Jean-Philippe

    2004-05-01

    The concept of continuous and global care is acknowledged today by all as inherent to modern medicine. A working group gathered to propose models for the coordination of supportive care for all severe illnesses in the various private and public health care centres. The supportive care are defined as: "all care and supports necessary for ill people, at the same time as specific treatments, along all severe illnesses". This definition is inspired by that of "supportive care" given in 1990 by the MASCC (Multinational Association for Supportive Care in Cancer): "The total medical, nursing and psychosocial help which the patients need besides the specific treatment". It integrates as much the field of cure with possible after-effects as that of palliative care, the definition of which is clarified (initial and terminal palliative phases). Such a coordination is justified by the pluridisciplinarity and hyperspecialisation of the professionals, by a poor communication between the teams, by the administrative difficulties encountered by the teams participating in the supportive care. The working group insists on the fact that the supportive care is not a new speciality. He proposes the creation of units. departments or pole of responsibility of supportive care with a "basic coordination" involving the activities of chronic pain, palliative care, psycho-oncology, and social care. This coordination can be extended, according to the "history" and missions of health care centres. Service done with the implementation of a "unique counter" for the patients and the teams is an important point. The structure has to comply with the terms and conditions of contract (Consultation, Unit or Centre of chronic pain, structures of palliative care, of psycho-oncology, of nutrition, of social care). A common technical organization is one of the interests. The structure has to set up strong links with the private practitioners, the networks, the home medical care (HAD) and the nurses

  9. A unit paradox for artificial neuronal networks.

    PubMed

    Lábos, E

    1993-01-01

    In formal or artificial neuronal networks (FNN; ANN) built of threshold logic gates, a unit step function is used. Recently the step function has been replaced by an S-shaped curve. This replacement is common and many studies are based on this substitution, often combined rarely not with some adaptive or learning procedure. However, the dynamical consequences e. g. in the time course of single unit discharges have not been sufficiently examined. The concepts of unit (neuron) and network in these models of engineering and neurobiology correspond to each other only partially: model units may behave similarly to real nets of real units. This is called here a unit paradox. Propositions are presented to eliminate this apparent contradiction. A further paradox is also mentioned (Section 3). It seems necessary to reconsider the relationship of the various trends of neural network theory.

  10. [Karl Leonhard is "not interested!" - newly found original sources provide new insights into the organisational background of the Rodewisch propositions].

    PubMed

    Steinberg, Holger

    2014-03-01

    In 2013 at the Rodewisch Clinic for Psychiatry, four folders were found that contain original documents from the office of former head of the clinic Rolf Walther. These original sources provide new insights into the organisational background of the International Symposium on Psychiatric Rehabilitation of 1963, as a result of which the groundbreaking Rodewisch Propositions were framed. The documents founds reveal that, apart from the persons already identified, Halle/Saale - based hygienist Karlheinz Renker was deeply involved in the preparation of this event. They also show that for ideological reasons the GDR Ministry of Health restricted the number of participants from non-socialist countries, in particular Western Germany, to be admitted. Finally, the sources suggest that a volume compiling all talks given at the symposium as one publication and as such making its content and resolutions known to a wider public failed, among other reasons, due to the fact that Karl Leonhard, then head of the GDR Association for Psychiatry and Neurology, was "not interested" in it. PMID:24254427

  11. Meaningful learning: The essential factor for conceptual change in limited or inappropriate propositional hierarchies leading to empowerment of learners

    NASA Astrophysics Data System (ADS)

    Novak, Joseph D.

    2002-07-01

    The construction and reconstruction of meanings by learners requires that they actively seek to integrate new knowledge with knowledge already in their cognitive structure. Ausubel's assimilation theory of cognitive learning has been shown to be effective in guiding research and instructional design to facilitate meaningful learning (Ausubel, The psychology of meaningful verbal learning, New York: Grune and Stratton, 1963; Educational psychology: A cognitive view, New York: Holt, Rinehart and Winston, 1968; The acquisition and retention of knowledge, Dordrecht: Kluwer, 2000). Gowin's Vee heuristic has been employed effectively to aid teachers and students in understanding the constructed nature of knowledge (Gowin, Educating, Ithaca, NY: Cornell University Press, 1981). Situated learning occurs when learning is by rote or at a lower level of meaningful learning. Concept mapping has been used effectively to aid meaningful learning with resulting modification of student's knowledge structures. When these knowledge structures are limited or faulty in some way, they may be referred to as Limited or Inappropriate Propositional Hierarchies (LIPH's). Conceptual change, or more accurately conceptual reconstrution, requires meaningful learning to modify LIPH's. Collaborative group learning facilitates meaningful learning and new knowledge construction. World-wide economic changes are forcing major changes in business and industry placing a premium on the power and value of knowledge and new knowledge production. These changes require changes in school and university education that centers on the nature and power of meaningful learning. New computer tools are available to facilitate teaching activities targeted at modifying LIPH's, and aiding meaningful learning in general.

  12. Human embryonic stem cell research and Proposition 71. Reflections on California’s response to federal policy.

    PubMed

    Burgin, Eileen

    2010-09-01

    In response to former President George W. Bush's funding limitations on human embryonic stem cell (hESC) research, California voters in 2004 passed Proposition 71, the most expansive state-funded medical research initiative in United States history. This study examines California's experiment in the life sciences, a particularly fitting analysis now as President Barack Obama has freed up additional federal funding for hESC research. In addition to exploring the general pitfalls of states, rather than the federal government, serving as principal players on hESC science and the perceived flaws in California's program, the analysis considers the strengths of state activism and of California's enterprise. On balance, given the Bush administration's policy on hESC research, the U.S. benefitted from state innovation. Moreover, even with the new federal regulatory policy on hESC research, California should be able to mesh its program with the federal initiative and remain a prime mover in this arena. The essay draws on informal interviews with key actors in California and on Capitol Hill in 2008 and 2009.

  13. Stimulating Conversation: Enhancement of Elicited Propositional Speech in a Patient with Chronic Nonfluent Aphasia Following Transcranial Magnetic Stimulation

    PubMed Central

    Hamilton, Roy H.; Sanders, Linda; Benson, Jennifer; Faseyitan, Olufunsho; Norise, Catherine; Naeser, Margaret; Martin, Paula; Coslett, H. Branch

    2010-01-01

    Although evidence suggests that patients with left hemisphere strokes and nonfluent aphasia who receive 1 Hz repetitive transcranial magnetic stimulation (rTMS) over the intact right inferior frontal gyrus experience persistent benefits in naming, it remains unclear whether the effects of rTMS in these patients generalize to other language abilities. We report a subject with chronic nonfluent aphasia who showed stable deficits of elicited propositional speech over the course of five years, and received 1200 pulses of 1 Hz rTMS daily for 10 days at a site identified as being optimally responsive to rTMS in this patient. Consistent with prior studies there was improvement in object naming, with a statistically significant improvement in action naming. Improvement was also demonstrated in picture description at 2, 6, and 10 months after rTMS with respect to the number of narrative words and nouns, sentence length, and use of closed class words. Compared to his baseline performance, the patient showed significant improvement on the Western Aphasia Battery subscale for spontaneous speech. These findings suggest that manipulation of the intact contralesional cortex in patients with nonfluent aphasia may result in language benefits that generalize beyond naming to include other aspects of language production. PMID:20159655

  14. Human embryonic stem cell research and Proposition 71. Reflections on California’s response to federal policy.

    PubMed

    Burgin, Eileen

    2010-09-01

    In response to former President George W. Bush's funding limitations on human embryonic stem cell (hESC) research, California voters in 2004 passed Proposition 71, the most expansive state-funded medical research initiative in United States history. This study examines California's experiment in the life sciences, a particularly fitting analysis now as President Barack Obama has freed up additional federal funding for hESC research. In addition to exploring the general pitfalls of states, rather than the federal government, serving as principal players on hESC science and the perceived flaws in California's program, the analysis considers the strengths of state activism and of California's enterprise. On balance, given the Bush administration's policy on hESC research, the U.S. benefitted from state innovation. Moreover, even with the new federal regulatory policy on hESC research, California should be able to mesh its program with the federal initiative and remain a prime mover in this arena. The essay draws on informal interviews with key actors in California and on Capitol Hill in 2008 and 2009. PMID:21761982

  15. Establishing propositional truth-value in counterfactual and real-world contexts during sentence comprehension: differential sensitivity of the left and right inferior frontal gyri.

    PubMed

    Nieuwland, Mante S

    2012-02-15

    What makes a proposition true or false has traditionally played an essential role in philosophical and linguistic theories of meaning. A comprehensive neurobiological theory of language must ultimately be able to explain the combined contributions of real-world truth-value and discourse context to sentence meaning. This fMRI study investigated the neural circuits that are sensitive to the propositional truth-value of sentences about counterfactual worlds, aiming to reveal differential hemispheric sensitivity of the inferior prefrontal gyri to counterfactual truth-value and real-world truth-value. Participants read true or false counterfactual conditional sentences ("If N.A.S.A. had not developed its Apollo Project, the first country to land on the moon would be Russia/America") and real-world sentences ("Because N.A.S.A. developed its Apollo Project, the first country to land on the moon has been America/Russia") that were matched on contextual constraint and truth-value. ROI analyses showed that whereas the left BA 47 showed similar activity increases to counterfactual false sentences and to real-world false sentences (compared to true sentences), the right BA 47 showed a larger increase for counterfactual false sentences. Moreover, whole-brain analyses revealed a distributed neural circuit for dealing with propositional truth-value. These results constitute the first evidence for hemispheric differences in processing counterfactual truth-value and real-world truth-value, and point toward additional right hemisphere involvement in counterfactual comprehension.

  16. Establishing propositional truth-value in counterfactual and real-world contexts during sentence comprehension: differential sensitivity of the left and right inferior frontal gyri.

    PubMed

    Nieuwland, Mante S

    2012-02-15

    What makes a proposition true or false has traditionally played an essential role in philosophical and linguistic theories of meaning. A comprehensive neurobiological theory of language must ultimately be able to explain the combined contributions of real-world truth-value and discourse context to sentence meaning. This fMRI study investigated the neural circuits that are sensitive to the propositional truth-value of sentences about counterfactual worlds, aiming to reveal differential hemispheric sensitivity of the inferior prefrontal gyri to counterfactual truth-value and real-world truth-value. Participants read true or false counterfactual conditional sentences ("If N.A.S.A. had not developed its Apollo Project, the first country to land on the moon would be Russia/America") and real-world sentences ("Because N.A.S.A. developed its Apollo Project, the first country to land on the moon has been America/Russia") that were matched on contextual constraint and truth-value. ROI analyses showed that whereas the left BA 47 showed similar activity increases to counterfactual false sentences and to real-world false sentences (compared to true sentences), the right BA 47 showed a larger increase for counterfactual false sentences. Moreover, whole-brain analyses revealed a distributed neural circuit for dealing with propositional truth-value. These results constitute the first evidence for hemispheric differences in processing counterfactual truth-value and real-world truth-value, and point toward additional right hemisphere involvement in counterfactual comprehension. PMID:22116039

  17. A Fair Proposition?

    ERIC Educational Resources Information Center

    Grobman, Arnold

    1993-01-01

    Describes problems with school science fairs including poor judging and a lack of understanding by the students of their own projects. Suggests improvements to the system. One suggestion is for science fair projects to be displayed only in classrooms and not district or regional fairs. (PR)

  18. A Sharing Proposition.

    ERIC Educational Resources Information Center

    Sturgeon, Julie

    2002-01-01

    Describes how the University of Vermont and St. Michael's College in Burlington, Vermont cooperated to share a single card access system. Discusses the planning, financial, and marketplace advantages of the cooperation. (EV)

  19. Probabilistic belief networks for genetic counseling.

    PubMed

    Harris, N L

    1990-05-01

    This paper describes a program, GenInfer, which uses belief networks to calculate risks of inheriting genetic disorders. GenInfer is based on Pearl's (J. Pearl, Artif. Intell. 29 (1986) 241-288) algorithm for fusion and propagation in probabilistic belief networks. It is written in Common Lisp. GenInfer can calculate genotypes for any family affected with any single-gene inherited disorder. Besides considering both negative and positive information in the pedigree. GenInfer takes into account additional information about the specific disorder as well as supplementary information for family members. The output consists of genotype probabilities for all family members and estimated genetic risks for prospective children of the consultands. Belief networks provide a way to calculate probabilities for systems of conditionally dependent variables. The impacts of various pieces of information are propagated and fused in such a way that, when equilibrium is reached, each proposition can be assigned a degree of belief consistent with the axioms of probability theory. In Pearl's algorithm, information is communicated through the network by messages sent between nodes. Pearl's basic algorithm cannot directly handle multiple-connected networks, which arise in the genetic counseling domain whenever a family pedigree includes consanguinity or more than one child per couple. GenInfer makes use of two cycle breaking methods, clustering and conditioning, to handle these situations. PMID:2401132

  20. Power-law behavior in complex organizational communication networks during crisis

    NASA Astrophysics Data System (ADS)

    Uddin, Shahadat; Murshed, Shahriar Tanvir Hasan; Hossain, Liaquat

    2011-08-01

    Communication networks can be described as patterns of contacts which are created due to the flow of messages and information shared among participating actors. Contemporary organizations are now commonly viewed as dynamic systems of adaptation and evolution containing several parts, which interact with one another both in internal and in external environment. Although there is limited consensus among researchers on the precise definition of organizational crisis, there is evidence of shared meaning: crisis produces individual crisis, crisis can be associated with positive or negative conditions, crises can be situations having been precipitated quickly or suddenly or situations that have developed over time and are predictable etc. In this research, we study the power-law behavior of an organizational email communication network during crisis from complexity perspective. Power law simply describes that, the probability that a randomly selected node has k links (i.e. degree k) follows P(k)∼k, where γ is the degree exponent. We used social network analysis tools and techniques to analyze the email communication dataset. We tested two propositions: (1) as organization goes through crisis, a few actors, who are prominent or more active, will become central, and (2) the daily communication network as well as the actors in the communication network exhibit power-law behavior. Our preliminary results support these two propositions. The outcome of this study may provide significant advancement in exploring organizational communication network behavior during crisis.

  1. Logic integer programming models for signaling networks.

    PubMed

    Haus, Utz-Uwe; Niermann, Kathrin; Truemper, Klaus; Weismantel, Robert

    2009-05-01

    We propose a static and a dynamic approach to model biological signaling networks, and show how each can be used to answer relevant biological questions. For this, we use the two different mathematical tools of Propositional Logic and Integer Programming. The power of discrete mathematics for handling qualitative as well as quantitative data has so far not been exploited in molecular biology, which is mostly driven by experimental research, relying on first-order or statistical models. The arising logic statements and integer programs are analyzed and can be solved with standard software. For a restricted class of problems the logic models reduce to a polynomial-time solvable satisfiability algorithm. Additionally, a more dynamic model enables enumeration of possible time resolutions in poly-logarithmic time. Computational experiments are included.

  2. Network Cosmology

    PubMed Central

    Krioukov, Dmitri; Kitsak, Maksim; Sinkovits, Robert S.; Rideout, David; Meyer, David; Boguñá, Marián

    2012-01-01

    Prediction and control of the dynamics of complex networks is a central problem in network science. Structural and dynamical similarities of different real networks suggest that some universal laws might accurately describe the dynamics of these networks, albeit the nature and common origin of such laws remain elusive. Here we show that the causal network representing the large-scale structure of spacetime in our accelerating universe is a power-law graph with strong clustering, similar to many complex networks such as the Internet, social, or biological networks. We prove that this structural similarity is a consequence of the asymptotic equivalence between the large-scale growth dynamics of complex networks and causal networks. This equivalence suggests that unexpectedly similar laws govern the dynamics of complex networks and spacetime in the universe, with implications to network science and cosmology. PMID:23162688

  3. Network cosmology.

    PubMed

    Krioukov, Dmitri; Kitsak, Maksim; Sinkovits, Robert S; Rideout, David; Meyer, David; Boguñá, Marián

    2012-01-01

    Prediction and control of the dynamics of complex networks is a central problem in network science. Structural and dynamical similarities of different real networks suggest that some universal laws might accurately describe the dynamics of these networks, albeit the nature and common origin of such laws remain elusive. Here we show that the causal network representing the large-scale structure of spacetime in our accelerating universe is a power-law graph with strong clustering, similar to many complex networks such as the Internet, social, or biological networks. We prove that this structural similarity is a consequence of the asymptotic equivalence between the large-scale growth dynamics of complex networks and causal networks. This equivalence suggests that unexpectedly similar laws govern the dynamics of complex networks and spacetime in the universe, with implications to network science and cosmology.

  4. Incorporating a Public Health Approach in Drug Law: Lessons from Local Expansion of Treatment Capacity and Access under California's Proposition 36

    PubMed Central

    Klein, Dorie; Miller, Robin E; Noble, Amanda; Speiglman, Richard

    2004-01-01

    A major state drug abuse initiative, California's Proposition 36 of 2000, mandated that adults convicted of drug possession be offered treatment in lieu of incarceration. While the law expanded public treatment for arrestees, the counties were given discretion in structuring their systems of care and procedures to manage clients. Using data from a study of key informants in eight counties, this article examines local planning to increase drug treatment capacity and manage clients’ access to treatment. In both these planning domains, it describes the counties’ strategies and concerns, reasons for their differences in approaches, and whether and how this state initiative, which explicitly incorporated treatment objectives into penal drug law, will shift the debate over drug abuse policy toward greater consideration of public health goals. PMID:15595948

  5. Associative learning as higher order cognition: Learning in human and nonhuman animals from the perspective of propositional theories and relational frame theory.

    PubMed

    De Houwer, Jan; Hughes, Sean; Barnes-Holmes, Dermot

    2016-08-01

    We aim to provide a new perspective on the old debate about whether evidence for higher order cognition in nonhuman animals can be reinterpreted in terms of associative learning. Our starting point is the idea that associative learning is best thought of as an effect (i.e., the impact of paired events on behavior) rather than a specific mental process (e.g., the formation of associations). This idea allows us to consider (a) propositional theories according to which associative learning is mediated by higher order mental processes akin to problem solving and (b) relational frame theory that allows one to think of seemingly simple associative learning effects as instances of a complex phenomenon known as arbitrarily applicable relational responding. Based on these 2 theories, we argue that (a) higher order cognition and associative learning are not necessarily mutually exclusive and (b) a more sophisticated conceptualization of higher order cognition is warranted. (PsycINFO Database Record

  6. Brain networks shaping religious belief.

    PubMed

    Kapogiannis, Dimitrios; Deshpande, Gopikrishna; Krueger, Frank; Thornburg, Matthew P; Grafman, Jordan Henry

    2014-02-01

    We previously demonstrated with functional magnetic resonance imaging (fMRI) that religious belief depends upon three cognitive dimensions, which can be mapped to specific brain regions. In the present study, we considered these co-activated regions as nodes of three networks each one corresponding to a particular dimension, corresponding to each dimension and examined the causal flow within and between these networks to address two important hypotheses that remained untested in our previous work. First, we hypothesized that regions involved in theory of mind (ToM) are located upstream the causal flow and drive non-ToM regions, in line with theories attributing religion to the evolution of ToM. Second, we hypothesized that differences in directional connectivity are associated with differences in religiosity. To test these hypotheses, we performed a multivariate Granger causality-based directional connectivity analysis of fMRI data to demonstrate the causal flow within religious belief-related networks. Our results supported both hypotheses. Religious subjects preferentially activated a pathway from inferolateral to dorsomedial frontal cortex to monitor the intent and involvement of supernatural agents (SAs; intent-related ToM). Perception of SAs engaged pathways involved in fear regulation and affective ToM. Religious beliefs are founded both on propositional statements for doctrine, but also on episodic memory and imagery. Beliefs based on doctrine engaged a pathway from Broca's to Wernicke's language areas. Beliefs related to everyday life experiences engaged pathways involved in imagery. Beliefs implying less involved SAs and evoking imagery activated a pathway from right lateral temporal to occipital regions. This pathway was more active in non-religious compared to religious subjects, suggesting greater difficulty and procedural demands for imagining and processing the intent of SAs. Insights gained by Granger connectivity analysis inform us about the causal

  7. Network Solutions.

    ERIC Educational Resources Information Center

    Vietzke, Robert; And Others

    1996-01-01

    This special section explains the latest developments in networking technologies, profiles school districts benefiting from successful implementations, and reviews new products for building networks. Highlights include ATM (asynchronous transfer mode), cable modems, networking switches, Internet screening software, file servers, network management…

  8. School District Expenditure and Tax Controls. A Summary of Tax and Expenditure Limitation Efforts in the Wake of Proposition 13, Existing Budget and Tax Rate Procedures and Bond Election Requirements.

    ERIC Educational Resources Information Center

    Education Commission of the States, Denver, CO. Dept. of Research and Information Services.

    The success of Proposition 13 in California gave impetus to similar tax limitation efforts in other states. Information included in this booklet is intended to help local, state, and federal education finance policy-makers wrestling with this issue. The first section summarizes efforts in each state to limit taxation and expenditure both by…

  9. Seeds of Prosperity: Public Investment in Science and Technology Research. A Study of the Economic Potential of Proposition 301 at Arizona State University and a New Model for Assessing Its Long-Term Value.

    ERIC Educational Resources Information Center

    Melnick, Rob; Heffernon, Rick; Welch, Nancy

    The approval of Proposition 301 by Arizona voters in November 2000 was a significant step toward a new foundation for the state's economic future by providing a long-term funding stream for science and technology investments. This new sales tax enabled the state to create an economic development strategy appropriate for the knowledge economy. This…

  10. Semantic Networks and Social Networks

    ERIC Educational Resources Information Center

    Downes, Stephen

    2005-01-01

    Purpose: To illustrate the need for social network metadata within semantic metadata. Design/methodology/approach: Surveys properties of social networks and the semantic web, suggests that social network analysis applies to semantic content, argues that semantic content is more searchable if social network metadata is merged with semantic web…

  11. Functional Integration between Salience and Central Executive Networks: A Role for Action Video Game Experience.

    PubMed

    Gong, Diankun; He, Hui; Ma, Weiyi; Liu, Dongbo; Huang, Mengting; Dong, Li; Gong, Jinnan; Li, Jianfu; Luo, Cheng; Yao, Dezhong

    2016-01-01

    Action video games (AVGs) have attracted increasing research attention as they offer a unique perspective into the relation between active learning and neural plasticity. However, little research has examined the relation between AVG experience and the plasticity of neural network mechanisms. It has been proposed that AVG experience is related to the integration between Salience Network (SN) and Central Executive Network (CEN), which are responsible for attention and working memory, respectively, two cognitive functions essential for AVG playing. This study initiated a systematic investigation of this proposition by analyzing AVG experts' and amateurs' resting-state brain functions through graph theoretical analyses and functional connectivity. Results reveal enhanced intra- and internetwork functional integrations in AVG experts compared to amateurs. The findings support the possible relation between AVG experience and the neural network plasticity. PMID:26885408

  12. Satisfiability of logic programming based on radial basis function neural networks

    NASA Astrophysics Data System (ADS)

    Hamadneh, Nawaf; Sathasivam, Saratha; Tilahun, Surafel Luleseged; Choon, Ong Hong

    2014-07-01

    In this paper, we propose a new technique to test the Satisfiability of propositional logic programming and quantified Boolean formula problem in radial basis function neural networks. For this purpose, we built radial basis function neural networks to represent the proportional logic which has exactly three variables in each clause. We used the Prey-predator algorithm to calculate the output weights of the neural networks, while the K-means clustering algorithm is used to determine the hidden parameters (the centers and the widths). Mean of the sum squared error function is used to measure the activity of the two algorithms. We applied the developed technique with the recurrent radial basis function neural networks to represent the quantified Boolean formulas. The new technique can be applied to solve many applications such as electronic circuits and NP-complete problems.

  13. Satisfiability of logic programming based on radial basis function neural networks

    SciTech Connect

    Hamadneh, Nawaf; Sathasivam, Saratha; Tilahun, Surafel Luleseged; Choon, Ong Hong

    2014-07-10

    In this paper, we propose a new technique to test the Satisfiability of propositional logic programming and quantified Boolean formula problem in radial basis function neural networks. For this purpose, we built radial basis function neural networks to represent the proportional logic which has exactly three variables in each clause. We used the Prey-predator algorithm to calculate the output weights of the neural networks, while the K-means clustering algorithm is used to determine the hidden parameters (the centers and the widths). Mean of the sum squared error function is used to measure the activity of the two algorithms. We applied the developed technique with the recurrent radial basis function neural networks to represent the quantified Boolean formulas. The new technique can be applied to solve many applications such as electronic circuits and NP-complete problems.

  14. Functional Integration between Salience and Central Executive Networks: A Role for Action Video Game Experience.

    PubMed

    Gong, Diankun; He, Hui; Ma, Weiyi; Liu, Dongbo; Huang, Mengting; Dong, Li; Gong, Jinnan; Li, Jianfu; Luo, Cheng; Yao, Dezhong

    2016-01-01

    Action video games (AVGs) have attracted increasing research attention as they offer a unique perspective into the relation between active learning and neural plasticity. However, little research has examined the relation between AVG experience and the plasticity of neural network mechanisms. It has been proposed that AVG experience is related to the integration between Salience Network (SN) and Central Executive Network (CEN), which are responsible for attention and working memory, respectively, two cognitive functions essential for AVG playing. This study initiated a systematic investigation of this proposition by analyzing AVG experts' and amateurs' resting-state brain functions through graph theoretical analyses and functional connectivity. Results reveal enhanced intra- and internetwork functional integrations in AVG experts compared to amateurs. The findings support the possible relation between AVG experience and the neural network plasticity.

  15. Functional Integration between Salience and Central Executive Networks: A Role for Action Video Game Experience

    PubMed Central

    Gong, Diankun; He, Hui; Ma, Weiyi; Liu, Dongbo; Huang, Mengting; Dong, Li; Gong, Jinnan; Li, Jianfu; Yao, Dezhong

    2016-01-01

    Action video games (AVGs) have attracted increasing research attention as they offer a unique perspective into the relation between active learning and neural plasticity. However, little research has examined the relation between AVG experience and the plasticity of neural network mechanisms. It has been proposed that AVG experience is related to the integration between Salience Network (SN) and Central Executive Network (CEN), which are responsible for attention and working memory, respectively, two cognitive functions essential for AVG playing. This study initiated a systematic investigation of this proposition by analyzing AVG experts' and amateurs' resting-state brain functions through graph theoretical analyses and functional connectivity. Results reveal enhanced intra- and internetwork functional integrations in AVG experts compared to amateurs. The findings support the possible relation between AVG experience and the neural network plasticity. PMID:26885408

  16. Dynamic Network Mechanisms of Relational Integration

    PubMed Central

    Parkin, Beth L.; Hellyer, Peter J.; Leech, Robert

    2015-01-01

    A prominent hypothesis states that specialized neural modules within the human lateral frontopolar cortices (LFPCs) support “relational integration” (RI), the solving of complex problems using inter-related rules. However, it has been proposed that LFPC activity during RI could reflect the recruitment of additional “domain-general” resources when processing more difficult problems in general as opposed to RI specifically. Moreover, theoretical research with computational models has demonstrated that RI may be supported by dynamic processes that occur throughout distributed networks of brain regions as opposed to within a discrete computational module. Here, we present fMRI findings from a novel deductive reasoning paradigm that controls for general difficulty while manipulating RI demands. In accordance with the domain-general perspective, we observe an increase in frontoparietal activation during challenging problems in general as opposed to RI specifically. Nonetheless, when examining frontoparietal activity using analyses of phase synchrony and psychophysiological interactions, we observe increased network connectivity during RI alone. Moreover, dynamic causal modeling with Bayesian model selection identifies the LFPC as the effective connectivity source. Based on these results, we propose that during RI an increase in network connectivity and a decrease in network metastability allows rules that are coded throughout working memory systems to be dynamically bound. This change in connectivity state is top-down propagated via a hierarchical system of domain-general networks with the LFPC at the apex. In this manner, the functional network perspective reconciles key propositions of the globalist, modular, and computational accounts of RI within a single unified framework. PMID:25995457

  17. Fermionic networks

    NASA Astrophysics Data System (ADS)

    Javarone, Marco Alberto

    2016-08-01

    We study the structure of fermionic networks, i.e. a model of networks based on the behavior of fermionic gases, and we analyze dynamical processes over them. In this model, particle dynamics have been mapped to the domain of networks, hence a parameter representing the temperature controls the evolution of the system. In doing so, it is possible to generate adaptive networks, i.e. networks whose structure varies over time. As shown in previous works, networks generated by quantum statistics can undergo critical phenomena as phase transitions and, moreover, they can be considered as thermodynamic systems. In this study, we analyze fermionic networks and opinion dynamics processes over them, framing this network model as a computational model useful to represent complex and adaptive systems. Results highlight that a strong relation holds between the gas temperature and the structure of the achieved networks. Notably, both the degree distribution and the assortativity vary as the temperature varies, hence we can state that fermionic networks behave as adaptive networks. On the other hand, it is worth to highlight that we did not finding relation between outcomes of opinion dynamics processes and the gas temperature. Therefore, although the latter plays a fundamental role in gas dynamics, on the network domain, its importance is related only to structural properties of fermionic networks.

  18. Topic segmentation via community detection in complex networks.

    PubMed

    de Arruda, Henrique F; Costa, Luciano da F; Amancio, Diego R

    2016-06-01

    Many real systems have been modeled in terms of network concepts, and written texts are a particular example of information networks. In recent years, the use of network methods to analyze language has allowed the discovery of several interesting effects, including the proposition of novel models to explain the emergence of fundamental universal patterns. While syntactical networks, one of the most prevalent networked models of written texts, display both scale-free and small-world properties, such a representation fails in capturing other textual features, such as the organization in topics or subjects. We propose a novel network representation whose main purpose is to capture the semantical relationships of words in a simple way. To do so, we link all words co-occurring in the same semantic context, which is defined in a threefold way. We show that the proposed representations favor the emergence of communities of semantically related words, and this feature may be used to identify relevant topics. The proposed methodology to detect topics was applied to segment selected Wikipedia articles. We found that, in general, our methods outperform traditional bag-of-words representations, which suggests that a high-level textual representation may be useful to study the semantical features of texts. PMID:27368785

  19. Topic segmentation via community detection in complex networks

    NASA Astrophysics Data System (ADS)

    de Arruda, Henrique F.; Costa, Luciano da F.; Amancio, Diego R.

    2016-06-01

    Many real systems have been modeled in terms of network concepts, and written texts are a particular example of information networks. In recent years, the use of network methods to analyze language has allowed the discovery of several interesting effects, including the proposition of novel models to explain the emergence of fundamental universal patterns. While syntactical networks, one of the most prevalent networked models of written texts, display both scale-free and small-world properties, such a representation fails in capturing other textual features, such as the organization in topics or subjects. We propose a novel network representation whose main purpose is to capture the semantical relationships of words in a simple way. To do so, we link all words co-occurring in the same semantic context, which is defined in a threefold way. We show that the proposed representations favor the emergence of communities of semantically related words, and this feature may be used to identify relevant topics. The proposed methodology to detect topics was applied to segment selected Wikipedia articles. We found that, in general, our methods outperform traditional bag-of-words representations, which suggests that a high-level textual representation may be useful to study the semantical features of texts.

  20. Network Basics.

    ERIC Educational Resources Information Center

    Tennant, Roy

    1992-01-01

    Explains how users can find and access information resources available on the Internet. Highlights include network information centers (NICs); lists, both formal and informal; computer networking protocols, including international standards; electronic mail; remote log-in; and file transfer. (LRW)

  1. Network science.

    PubMed

    Barabási, Albert-László

    2013-03-28

    Professor Barabási's talk described how the tools of network science can help understand the Web's structure, development and weaknesses. The Web is an information network, in which the nodes are documents (at the time of writing over one trillion of them), connected by links. Other well-known network structures include the Internet, a physical network where the nodes are routers and the links are physical connections, and organizations, where the nodes are people and the links represent communications.

  2. Evolving Scale-Free Networks by Poisson Process: Modeling and Degree Distribution.

    PubMed

    Feng, Minyu; Qu, Hong; Yi, Zhang; Xie, Xiurui; Kurths, Jurgen

    2016-05-01

    Since the great mathematician Leonhard Euler initiated the study of graph theory, the network has been one of the most significant research subject in multidisciplinary. In recent years, the proposition of the small-world and scale-free properties of complex networks in statistical physics made the network science intriguing again for many researchers. One of the challenges of the network science is to propose rational models for complex networks. In this paper, in order to reveal the influence of the vertex generating mechanism of complex networks, we propose three novel models based on the homogeneous Poisson, nonhomogeneous Poisson and birth death process, respectively, which can be regarded as typical scale-free networks and utilized to simulate practical networks. The degree distribution and exponent are analyzed and explained in mathematics by different approaches. In the simulation, we display the modeling process, the degree distribution of empirical data by statistical methods, and reliability of proposed networks, results show our models follow the features of typical complex networks. Finally, some future challenges for complex systems are discussed.

  3. Evolving Scale-Free Networks by Poisson Process: Modeling and Degree Distribution.

    PubMed

    Feng, Minyu; Qu, Hong; Yi, Zhang; Xie, Xiurui; Kurths, Jurgen

    2016-05-01

    Since the great mathematician Leonhard Euler initiated the study of graph theory, the network has been one of the most significant research subject in multidisciplinary. In recent years, the proposition of the small-world and scale-free properties of complex networks in statistical physics made the network science intriguing again for many researchers. One of the challenges of the network science is to propose rational models for complex networks. In this paper, in order to reveal the influence of the vertex generating mechanism of complex networks, we propose three novel models based on the homogeneous Poisson, nonhomogeneous Poisson and birth death process, respectively, which can be regarded as typical scale-free networks and utilized to simulate practical networks. The degree distribution and exponent are analyzed and explained in mathematics by different approaches. In the simulation, we display the modeling process, the degree distribution of empirical data by statistical methods, and reliability of proposed networks, results show our models follow the features of typical complex networks. Finally, some future challenges for complex systems are discussed. PMID:25956002

  4. Superelastic networks

    SciTech Connect

    Obukhov, S.P.; Rubinstein, M.; Colby, R.H.

    1993-12-31

    This paper discusses the elastic modulus, swelling, and deswelling behavior of networks as a function of their concentration and the preparation state. Based on these results, the authors expect that networks prepared by crosslinking long chains at low concentration, followed by removal of solvent, will have superelastic properties - the deswollen networks will have low modulus and will be capable of stretching by enormous amounts without breaking. This is because deswelling introduces only temporary entanglements. These temporary entanglements change the static configuration of the network strands. The authors discuss the non-Gaussian nature of these strands and the linear viscoelastic response of the superelastic networks.

  5. Networking computers.

    PubMed

    McBride, D C

    1997-03-01

    This decade the role of the personal computer has shifted dramatically from a desktop device designed to increase individual productivity and efficiency to an instrument of communication linking people and machines in different places with one another. A computer in one city can communicate with another that may be thousands of miles away. Networking is how this is accomplished. Just like the voice network used by the telephone, computer networks transmit data and other information via modems over these same telephone lines. A network can be created over both short and long distances. Networks can be established within a hospital or medical building or over many hospitals or buildings covering many geographic areas. Those confined to one location are called LANs, local area networks. Those that link computers in one building to those at other locations are known as WANs, or wide area networks. The ultimate wide area network is the one we've all been hearing so much about these days--the Internet, and its World Wide Web. Setting up a network is a process that requires careful planning and commitment. To avoid potential pitfalls and to make certain the network you establish meets your needs today and several years down the road, several steps need to be followed. This article reviews the initial steps involved in getting ready to network.

  6. Vulnerability of network of networks

    NASA Astrophysics Data System (ADS)

    Havlin, S.; Kenett, D. Y.; Bashan, A.; Gao, J.; Stanley, H. E.

    2014-10-01

    Our dependence on networks - be they infrastructure, economic, social or others - leaves us prone to crises caused by the vulnerabilities of these networks. There is a great need to develop new methods to protect infrastructure networks and prevent cascade of failures (especially in cases of coupled networks). Terrorist attacks on transportation networks have traumatized modern societies. With a single blast, it has become possible to paralyze airline traffic, electric power supply, ground transportation or Internet communication. How, and at which cost can one restructure the network such that it will become more robust against malicious attacks? The gradual increase in attacks on the networks society depends on - Internet, mobile phone, transportation, air travel, banking, etc. - emphasize the need to develop new strategies to protect and defend these crucial networks of communication and infrastructure networks. One example is the threat of liquid explosives a few years ago, which completely shut down air travel for days, and has created extreme changes in regulations. Such threats and dangers warrant the need for new tools and strategies to defend critical infrastructure. In this paper we review recent advances in the theoretical understanding of the vulnerabilities of interdependent networks with and without spatial embedding, attack strategies and their affect on such networks of networks as well as recently developed strategies to optimize and repair failures caused by such attacks.

  7. Computer Networks As Social Networks

    NASA Astrophysics Data System (ADS)

    Wellman, Barry

    2001-09-01

    Computer networks are inherently social networks, linking people, organizations, and knowledge. They are social institutions that should not be studied in isolation but as integrated into everyday lives. The proliferation of computer networks has facilitated a deemphasis on group solidarities at work and in the community and afforded a turn to networked societies that are loosely bounded and sparsely knit. The Internet increases people's social capital, increasing contact with friends and relatives who live nearby and far away. New tools must be developed to help people navigate and find knowledge in complex, fragmented, networked societies.

  8. Associative and Propositional Processes in Evaluation: Conceptual, Empirical, and Metatheoretical Issues--Reply to Albarracin, Hart, and McCulloch (2006), Kruglanski and Dechesne (2006), and Petty and Brinol (2006)

    ERIC Educational Resources Information Center

    Gawronski, Bertram; Bodenhausen, Galen V.

    2006-01-01

    Replies to commentaries by D. Albarracin, W. Hart, and K. C. McCulloch (see record 2006-10465-004), A. W. Kruglanski and M. Dechesne (see record 2006-10465-005), and R. E. Petty and P. Brinol (see record 2006-10465-006) on B. Gawronski and G. V. Bodenhausen's (2006; see record 2006-10465-003) recently proposed associative-propositional evaluation…

  9. Differential evolution based on the node degree of its complex network: Initial study

    NASA Astrophysics Data System (ADS)

    Skanderova, Lenka; Zelinka, Ivan

    2016-06-01

    In this paper is reported our progress in the synthesis of two partially different areas of research: complex networks and evolutionary computation. Ideas and results reported and mentioned here are based on our previous results and experiments. The main core of our participation is an evolutionary algorithm performance improvement by means of complex network use. Complex network is related to the evolutionary dynamics and reflect it. We report here our latest results as well as propositions on further research that is in process in our group (http://navy.cs.vsb.cz/). Only the main ideas and results are reported here, for more details it is recommended to read related literature of our previous research and results.

  10. Innovation Networks

    NASA Astrophysics Data System (ADS)

    Pyka, Andreas; Scharnhorst, Andrea

    The idea for this book started when we organized a topical workshop entitled "Innovation Networks - New Approaches in Modeling and Analyzing" (held in Augsburg, Germany in October 2005), under the auspices of Exystence, a network of excellence funded in the European Union's Fifth Framework Program. Unlike other conferences on innovation and networks, however, this workshop brought together scientists from economics, sociology, communication science, science and technology studies, and physics. With this book we aim to build further on a bridge connecting the bodies of knowledge on networks in economics, the social sciences and, more recently, statistical physics.

  11. Plug-In Hybrid Electric Vehicle Value Proposition Study: Phase 1, Task 3: Technical Requirements and Procedure for Evaluation of One Scenario

    SciTech Connect

    Sikes, Karen R; Hinds, Shaun; Hadley, Stanton W; McGill, Ralph N; Markel, Lawrence C; Ziegler, Richard E; Smith, David E; Smith, Richard L; Greene, David L; Brooks, Daniel L; Wiegman, Herman; Miller, Nicholas; Marano, Dr. Vincenzo

    2008-07-01

    In Task 2, the project team designed the Phase 1 case study to represent the 'baseline' plug-in hybrid electric vehicle (PHEV) fleet of 2030 that investigates the effects of seventeen (17) value propositions (see Table 1 for complete list). By creating a 'baseline' scenario, a consistent set of assumptions and model parameters can be established for use in more elaborate Phase 2 case studies. The project team chose southern California as the Phase 1 case study location because the economic, environmental, social, and regulatory conditions are conducive to the advantages of PHEVs. Assuming steady growth of PHEV sales over the next two decades, PHEVs are postulated to comprise approximately 10% of the area's private vehicles (about 1,000,000 vehicles) in 2030. New PHEV models introduced in 2030 are anticipated to contain lithium-ion batteries and be classified by a blended mileage description (e.g., 100 mpg, 150 mpg) that demonstrates a battery size equivalence of a PHEV-30. Task 3 includes the determination of data, models, and analysis procedures required to evaluate the Phase 1 case study scenario. Some existing models have been adapted to accommodate the analysis of the business model and establish relationships between costs and value to the respective consumers. Other data, such as the anticipated California generation mix and southern California drive cycles, have also been gathered for use as inputs. The collection of models that encompasses the technical, economic, and financial aspects of Phase 1 analysis has been chosen and is described in this deliverable. The role of PHEV owners, utilities (distribution systems, generators, independent system operators (ISO), aggregators, or regional transmission operators (RTO)), facility owners, financing institutions, and other third parties are also defined.

  12. Network Directory.

    ERIC Educational Resources Information Center

    Butler, Jocelyn A.; Batey, Anne

    This Network Directory is part of the effort by the Northwest Regional Educational Laboratory (NWREL) School Improvement Program to promote communication among educational professionals about school improvement. Specifically, the directory is designed to provide information for networking among schools involved in systematic, long-term…

  13. Diabetes network.

    PubMed

    2016-07-01

    Diabetes UK has launched a network of information and support for commissioning and improvement in diabetes care. The network is free to join and offers monthly updates on good practice from around the UK, a forum for sharing ideas and learning, and access to Diabetes UK resources. PMID:27369708

  14. Temporal networks

    NASA Astrophysics Data System (ADS)

    Holme, Petter; Saramäki, Jari

    2012-10-01

    A great variety of systems in nature, society and technology-from the web of sexual contacts to the Internet, from the nervous system to power grids-can be modeled as graphs of vertices coupled by edges. The network structure, describing how the graph is wired, helps us understand, predict and optimize the behavior of dynamical systems. In many cases, however, the edges are not continuously active. As an example, in networks of communication via e-mail, text messages, or phone calls, edges represent sequences of instantaneous or practically instantaneous contacts. In some cases, edges are active for non-negligible periods of time: e.g., the proximity patterns of inpatients at hospitals can be represented by a graph where an edge between two individuals is on throughout the time they are at the same ward. Like network topology, the temporal structure of edge activations can affect dynamics of systems interacting through the network, from disease contagion on the network of patients to information diffusion over an e-mail network. In this review, we present the emergent field of temporal networks, and discuss methods for analyzing topological and temporal structure and models for elucidating their relation to the behavior of dynamical systems. In the light of traditional network theory, one can see this framework as moving the information of when things happen from the dynamical system on the network, to the network itself. Since fundamental properties, such as the transitivity of edges, do not necessarily hold in temporal networks, many of these methods need to be quite different from those for static networks. The study of temporal networks is very interdisciplinary in nature. Reflecting this, even the object of study has many names-temporal graphs, evolving graphs, time-varying graphs, time-aggregated graphs, time-stamped graphs, dynamic networks, dynamic graphs, dynamical graphs, and so on. This review covers different fields where temporal graphs are considered

  15. Technological Networks

    NASA Astrophysics Data System (ADS)

    Mitra, Bivas

    The study of networks in the form of mathematical graph theory is one of the fundamental pillars of discrete mathematics. However, recent years have witnessed a substantial new movement in network research. The focus of the research is shifting away from the analysis of small graphs and the properties of individual vertices or edges to consideration of statistical properties of large scale networks. This new approach has been driven largely by the availability of technological networks like the Internet [12], World Wide Web network [2], etc. that allow us to gather and analyze data on a scale far larger than previously possible. At the same time, technological networks have evolved as a socio-technological system, as the concepts of social systems that are based on self-organization theory have become unified in technological networks [13]. In today’s society, we have a simple and universal access to great amounts of information and services. These information services are based upon the infrastructure of the Internet and the World Wide Web. The Internet is the system composed of ‘computers’ connected by cables or some other form of physical connections. Over this physical network, it is possible to exchange e-mails, transfer files, etc. On the other hand, the World Wide Web (commonly shortened to the Web) is a system of interlinked hypertext documents accessed via the Internet where nodes represent web pages and links represent hyperlinks between the pages. Peer-to-peer (P2P) networks [26] also have recently become a popular medium through which huge amounts of data can be shared. P2P file sharing systems, where files are searched and downloaded among peers without the help of central servers, have emerged as a major component of Internet traffic. An important advantage in P2P networks is that all clients provide resources, including bandwidth, storage space, and computing power. In this chapter, we discuss these technological networks in detail. The review

  16. Network representations of knowledge about chemical equilibrium: Variations with achievement

    NASA Astrophysics Data System (ADS)

    Wilson, Janice M.

    This study examined variation in the organization of domain-specific knowledge by 50 Year-12 chemistry students and 4 chemistry teachers. The study used nonmetric multidimensional scaling (MDS) and the Pathfinder network-generating algorithm to investigate individual and group differences in student concepts maps about chemical equilibrium. MDS was used to represent the individual maps in two-dimensional space, based on the presence or absence of paired propositional links. The resulting separation between maps reflected degree of hierarchical structure, but also reflected independent measures of student achievement. Pathfinder was then used to produce semantic networks from pooled data from high and low achievement groups using proximity matrices derived from the frequencies of paired concepts. The network constructed from maps of higher achievers (coherence measure = 0.18, linked pairs = 294, and number of subjects = 32) showed greater coherence, more concordance in specific paired links, more important specific conceptual relationships, and greater hierarchical organization than did the network constructed from maps of lower achievers (coherence measure = 0.12, linked pairs = 552, and number of subjects = 22). These differences are interpreted in terms of qualitative variation in knowledge organization by two groups of individuals with different levels of relative expertise (as reflected in achievement scores) concerning the topic of chemical equilibrium. The results suggest that the technique of transforming paired links in concept maps into proximity matrices for input to multivariate analyses provides a suitable methodology for comparing and documenting changes in the organization and structure of conceptual knowledge within and between individual students.

  17. ISO 14001 EMS VALUE PROPOSITION.

    SciTech Connect

    BRIGGS,S.L.K.

    2001-11-06

    The objective of this report is to identify business opportunities and value for Battelle Organizations to undertake IS0 14001 Environmental Management System Implementation and registration to the international standard as a corporate strategic initiative.

  18. Calcium Intake: A Lifelong Proposition.

    ERIC Educational Resources Information Center

    Amschler, Denise H.

    1985-01-01

    This article reviews the current problem of low calcium intake in the United States among all age groups, the role of calcium in the formation and maintenance of bone mass, and major factors influencing absorption. Osteoporosis is discussed, and current recommendations for Recommended Dietary allowance are provided. (Author/MT)

  19. Innovation network

    PubMed Central

    Acemoglu, Daron; Akcigit, Ufuk; Kerr, William R.

    2016-01-01

    Technological progress builds upon itself, with the expansion of invention in one domain propelling future work in linked fields. Our analysis uses 1.8 million US patents and their citation properties to map the innovation network and its strength. Past innovation network structures are calculated using citation patterns across technology classes during 1975–1994. The interaction of this preexisting network structure with patent growth in upstream technology fields has strong predictive power on future innovation after 1995. This pattern is consistent with the idea that when there is more past upstream innovation for a particular technology class to build on, then that technology class innovates more. PMID:27681628

  20. Sentinel Network

    Cancer.gov

    The Sentinel Network is an integrated, electronic, national medical product safety initiative that compiles information about the safe and effective use of medical products accessible to patients and healthcare practitioners.

  1. Developer Network

    SciTech Connect

    2012-08-21

    NREL's Developer Network, developer.nrel.gov, provides data that users can access to provide data to their own analyses, mobile and web applications. Developers can retrieve the data through a Web services API (application programming interface). The Developer Network handles overhead of serving up web services such as key management, authentication, analytics, reporting, documentation standards, and throttling in a common architecture, while allowing web services and APIs to be maintained and managed independently.

  2. Sentient networks

    SciTech Connect

    Chapline, G.

    1998-03-01

    The engineering problems of constructing autonomous networks of sensors and data processors that can provide alerts for dangerous situations provide a new context for debating the question whether man-made systems can emulate the cognitive capabilities of the mammalian brain. In this paper we consider the question whether a distributed network of sensors and data processors can form ``perceptions`` based on sensory data. Because sensory data can have exponentially many explanations, the use of a central data processor to analyze the outputs from a large ensemble of sensors will in general introduce unacceptable latencies for responding to dangerous situations. A better idea is to use a distributed ``Helmholtz machine`` architecture in which the sensors are connected to a network of simple processors, and the collective state of the network as a whole provides an explanation for the sensory data. In general communication within such a network will require time division multiplexing, which opens the door to the possibility that with certain refinements to the Helmholtz machine architecture it may be possible to build sensor networks that exhibit a form of artificial consciousness.

  3. Neural Networks

    SciTech Connect

    Smith, Patrick I.

    2003-09-23

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

  4. Well-connected leaders: the impact of leaders' social network ties on LMX and members' work attitudes.

    PubMed

    Venkataramani, Vijaya; Green, Stephen G; Schleicher, Deidra J

    2010-11-01

    We examined the proposition that leaders' social network ties in the larger organization influence the quality of their leader-member exchange (LMX) with their employees, which, in turn, impacts these employees' job satisfaction and turnover intentions. Using multilevel, multisource data from a field study of 184 bank employees nested within 42 branch managers, we found that leaders who had higher quality relationships with their bosses and who were more central in their peer networks were perceived by their subordinates as having greater status in the organization and, therefore, were able to form higher quality relationships with them. Further, the effects of the leaders' perceived status on LMX were stronger when subordinates were less central in their own peer network. Finally, LMX mediated the impact of leaders' perceived status in the organization on subordinates' job satisfaction and turnover intentions. Implications for theory and practice are discussed.

  5. Workshop on neural networks

    SciTech Connect

    Uhrig, R.E.; Emrich, M.L.

    1990-01-01

    The topics covered in this report are: Learning, Memory, and Artificial Neural Systems; Emerging Neural Network Technology; Neural Networks; Digital Signal Processing and Neural Networks; Application of Neural Networks to In-Core Fuel Management; Neural Networks in Process Control; Neural Network Applications in Image Processing; Neural Networks for Multi-Sensor Information Fusion; Neural Network Research in Instruments Controls Division; Neural Networks Research in the ORNL Engineering Physics and Mathematics Division; Neural Network Applications for Linear Programming; Neural Network Applications to Signal Processing and Diagnostics; Neural Networks in Filtering and Control; Neural Network Research at Tennessee Technological University; and Global Minima within the Hopfield Hypercube.

  6. Power-use in cooperative competition: a power-dependence model and an empirical test of network structure and geographic mobility.

    PubMed

    Robbins, Blaine; Welser, Howard T; Grigoryeva, Maria; Gleave, Eric

    2014-05-01

    Although the social exchange paradigm has produced a vibrant research program, the theoretical tradition is rarely used to model the structure of social networks outside of experiments and simulations. To address this limitation, we derive power-dependence predictions about network structure and geographic mobility-the outcomes of power-use-and test these predictions using complete data on competition networks and travel schedules among amateur sports teams. Poisson regression and exponential random graph models provide strong support for our predictions. The findings illustrate exchange dynamics in which status resources desired by teams, coupled with the availability of geographically proximal alternatives, create power and dependence that dictate where and with whom teams compete. Although evidence supports Georg Simmel's classic proposition that networks form on the basis of values and propinquity, we show that this complex dynamic is conditional on power and dependence. We conclude by discussing implications and directions for future research.

  7. Power-use in cooperative competition: a power-dependence model and an empirical test of network structure and geographic mobility.

    PubMed

    Robbins, Blaine; Welser, Howard T; Grigoryeva, Maria; Gleave, Eric

    2014-05-01

    Although the social exchange paradigm has produced a vibrant research program, the theoretical tradition is rarely used to model the structure of social networks outside of experiments and simulations. To address this limitation, we derive power-dependence predictions about network structure and geographic mobility-the outcomes of power-use-and test these predictions using complete data on competition networks and travel schedules among amateur sports teams. Poisson regression and exponential random graph models provide strong support for our predictions. The findings illustrate exchange dynamics in which status resources desired by teams, coupled with the availability of geographically proximal alternatives, create power and dependence that dictate where and with whom teams compete. Although evidence supports Georg Simmel's classic proposition that networks form on the basis of values and propinquity, we show that this complex dynamic is conditional on power and dependence. We conclude by discussing implications and directions for future research. PMID:24576632

  8. MAC protocol for ad hoc networks using a genetic algorithm.

    PubMed

    Elizarraras, Omar; Panduro, Marco; Méndez, Aldo L; Reyna, Alberto

    2014-01-01

    The problem of obtaining the transmission rate in an ad hoc network consists in adjusting the power of each node to ensure the signal to interference ratio (SIR) and the energy required to transmit from one node to another is obtained at the same time. Therefore, an optimal transmission rate for each node in a medium access control (MAC) protocol based on CSMA-CDMA (carrier sense multiple access-code division multiple access) for ad hoc networks can be obtained using evolutionary optimization. This work proposes a genetic algorithm for the transmission rate election considering a perfect power control, and our proposition achieves improvement of 10% compared with the scheme that handles the handshaking phase to adjust the transmission rate. Furthermore, this paper proposes a genetic algorithm that solves the problem of power combining, interference, data rate, and energy ensuring the signal to interference ratio in an ad hoc network. The result of the proposed genetic algorithm has a better performance (15%) compared to the CSMA-CDMA protocol without optimizing. Therefore, we show by simulation the effectiveness of the proposed protocol in terms of the throughput.

  9. MAC Protocol for Ad Hoc Networks Using a Genetic Algorithm

    PubMed Central

    Elizarraras, Omar; Panduro, Marco; Méndez, Aldo L.

    2014-01-01

    The problem of obtaining the transmission rate in an ad hoc network consists in adjusting the power of each node to ensure the signal to interference ratio (SIR) and the energy required to transmit from one node to another is obtained at the same time. Therefore, an optimal transmission rate for each node in a medium access control (MAC) protocol based on CSMA-CDMA (carrier sense multiple access-code division multiple access) for ad hoc networks can be obtained using evolutionary optimization. This work proposes a genetic algorithm for the transmission rate election considering a perfect power control, and our proposition achieves improvement of 10% compared with the scheme that handles the handshaking phase to adjust the transmission rate. Furthermore, this paper proposes a genetic algorithm that solves the problem of power combining, interference, data rate, and energy ensuring the signal to interference ratio in an ad hoc network. The result of the proposed genetic algorithm has a better performance (15%) compared to the CSMA-CDMA protocol without optimizing. Therefore, we show by simulation the effectiveness of the proposed protocol in terms of the throughput. PMID:25140339

  10. Network Views

    ERIC Educational Resources Information Center

    Alexander, Louis

    2010-01-01

    The world changed in 2008. The financial crisis brought with it a deepening sense of insecurity, and the desire to be connected to a network increased. Throughout the summer and fall of 2008, events were unfolding with alarming rapidity. The Massachusetts Institute of Technology (MIT) Alumni Association wanted to respond to this change in the…

  11. Network opportunity

    NASA Astrophysics Data System (ADS)

    Catanzaro, Michele; Buchanan, Mark

    2013-03-01

    Our developing scientific understanding of complex networks is being usefully applied in a wide set of financial systems. What we've learned from the 2008 crisis could be the basis of better management of the economy -- and a means to avert future disaster.

  12. Gradient networks

    NASA Astrophysics Data System (ADS)

    Toroczkai, Zoltán; Kozma, Balázs; Bassler, Kevin E.; Hengartner, N. W.; Korniss, G.

    2008-04-01

    Gradient networks are defined (Toroczkai and Bassler 2004 Nature 428 716) as directed graphs formed by local gradients of a scalar field distributed on the nodes of a substrate network G. We present the derivation for some of the general properties of gradient graphs and give an exact expression for the in-degree distribution R(l) of the gradient network when the substrate is a binomial (Erd{\\;\\kern -0.10em \\raise -0.35ex \\{{^{^{\\prime\\prime}}}}\\kern -0.57em \\o} s-Rényi) random graph, G_{N,p} , and the scalars are independent identically distributed (i.i.d.) random variables. We show that in the limit N \\to \\infty, p \\to 0, z = pN = \\mbox{const} \\gg 1, R(l)\\propto l^{-1} for l < l_c = z , i.e., gradient networks become scale-free graphs up to a cut-off degree. This paper presents the detailed derivation of the results announced in Toroczkai and Bassler (2004 Nature 428 716).

  13. Knowledge Networks

    ERIC Educational Resources Information Center

    McLeod, Scott

    2008-01-01

    The blogosphere and the Internet are both examples of complex, self-organizing networks. So too is the world of academic publishing. Some faculty members are prolific article and book writers. Their publications often are hubs, or even superhubs, in the scholarly literature, cited regularly by others. Some scholars might just be nodes, with…

  14. Beyond Networking.

    ERIC Educational Resources Information Center

    Carmel, Michael

    1981-01-01

    Discusses the new relationships between libraries and their users with reference to the worldwide medical information networks which have developed through the influence of the U.S. National Library of Medicine. Consideration is given to the new roles librarians will have to assume. (Author/LLS)

  15. Chemical networks

    NASA Astrophysics Data System (ADS)

    Thi, Wing-Fai

    2015-09-01

    This chapter discusses the fundamental ideas of how chemical networks are build, their strengths and limitations. The chemical reactions that occur in disks combine the cold phase reactions used to model cold molecular clouds with the hot chemistry applied to planetary atmosphere models. With a general understanding of the different types of reactions that can occur, one can proceed in building a network of chemical reactions and use it to explain the abundance of species seen in disks. One on-going research subject is finding new paths to synthesize species either in the gas-phase or on grain surfaces. Specific formation routes for water or carbon monoxide are discussed in more details. 13th Lecture of the Summer School "Protoplanetary Disks: Theory and Modelling Meet Observations"

  16. Modeling the citation network by network cosmology.

    PubMed

    Xie, Zheng; Ouyang, Zhenzheng; Zhang, Pengyuan; Yi, Dongyun; Kong, Dexing

    2015-01-01

    Citation between papers can be treated as a causal relationship. In addition, some citation networks have a number of similarities to the causal networks in network cosmology, e.g., the similar in-and out-degree distributions. Hence, it is possible to model the citation network using network cosmology. The casual network models built on homogenous spacetimes have some restrictions when describing some phenomena in citation networks, e.g., the hot papers receive more citations than other simultaneously published papers. We propose an inhomogenous causal network model to model the citation network, the connection mechanism of which well expresses some features of citation. The node growth trend and degree distributions of the generated networks also fit those of some citation networks well.

  17. NASA Network

    NASA Technical Reports Server (NTRS)

    Carter, David; Wetzel, Scott

    2000-01-01

    The NASA Network includes nine NASA operated and partner operated stations covering North America, the west coast of South America, the Pacific, and Western Australia . A new station is presently being setup in South Africa and discussions are underway to add another station in Argentina. NASA SLR operations are supported by Honeywell Technical Solutions, Inc (HTSI), formally AlliedSignal Technical Services, The University of Texas, the University of Hawaii and Universidad Nacional de San Agustin.

  18. Why Network? Theoretical Perspectives on Networking

    ERIC Educational Resources Information Center

    Muijs, Daniel; West, Mel; Ainscow, Mel

    2010-01-01

    In recent years, networking and collaboration have become increasingly popular in education. However, there is at present a lack of attention to the theoretical basis of networking, which could illuminate when and when not to network and under what conditions networks are likely to be successful. In this paper, we will attempt to sketch the…

  19. Communications Network

    NASA Technical Reports Server (NTRS)

    1990-01-01

    The Multi-Compatible Network Interface Unit (MCNIU) is intended to connect the space station's communications and tracking, guidance and navigation, life support, electric power, payload data, hand controls, display consoles and other systems, and also communicate with diverse processors. Honeywell is now marketing MCNIU commercially. It has applicability in certain military operations or civil control centers. It has nongovernment utility among large companies, universities and research organizations that transfer large amounts of data among workstations and computers. *This product is no longer commercially available.

  20. [Networks in cognitive research].

    PubMed

    Pléh, Csaba

    2012-01-01

    This review paper starts from discussing two models of network research: one starting from general networks, the other starting from the Ego. Ego based researches are characterized starting form the model of Dunbar as presenting networks of different size and intimacy, both in real and virtual networks. Researches into the personality determinants of networks mainly shows the effects of extroversion. The future of network research indicates a trend towards relating personal, conceptual, and neural networks.

  1. Robustness of a Network of Networks

    NASA Astrophysics Data System (ADS)

    Gao, Jianxi; Buldyrev, Sergey V.; Stanley, H. Eugene; Havlin, Shlomo

    2012-02-01

    Network research has been focused on studying the properties of a single isolated network, which rarely exists. We develop a general analytical framework for studying percolation of n interdependent networks. We illustrate our analytical solutions for three examples: (i) For any tree of n fully dependent Erdos-R'enyi (ER) networks, each of average degree k, we find that the giant component P∞=p[1-(-kP∞)]^n where 1 - p is the initial fraction of removed nodes. This general result coincides for n = 1 with the known second-order phase transition for a single network. For any n>1 cascading failures occur and the percolation becomes an abrupt first-order transition. (ii) For a starlike network of n partially interdependent ER networks, P∞ depends also on the topology--in contrast to case (i). (iii) For a looplike network formed by n partially dependent ER networks, P∞ is independent of n.

  2. Subgraphs and network motifs in geometric networks

    NASA Astrophysics Data System (ADS)

    Itzkovitz, Shalev; Alon, Uri

    2005-02-01

    Many real-world networks describe systems in which interactions decay with the distance between nodes. Examples include systems constrained in real space such as transportation and communication networks, as well as systems constrained in abstract spaces such as multivariate biological or economic data sets and models of social networks. These networks often display network motifs: subgraphs that recur in the network much more often than in randomized networks. To understand the origin of the network motifs in these networks, it is important to study the subgraphs and network motifs that arise solely from geometric constraints. To address this, we analyze geometric network models, in which nodes are arranged on a lattice and edges are formed with a probability that decays with the distance between nodes. We present analytical solutions for the numbers of all three- and four-node subgraphs, in both directed and nondirected geometric networks. We also analyze geometric networks with arbitrary degree sequences and models with a bias for directed edges in one direction. Scaling rules for scaling of subgraph numbers with system size, lattice dimension, and interaction range are given. Several invariant measures are found, such as the ratio of feedback and feed-forward loops, which do not depend on system size, dimension, or connectivity function. We find that network motifs in many real-world networks, including social networks and neuronal networks, are not captured solely by these geometric models. This is in line with recent evidence that biological network motifs were selected as basic circuit elements with defined information-processing functions.

  3. Nested Neural Networks

    NASA Technical Reports Server (NTRS)

    Baram, Yoram

    1992-01-01

    Report presents analysis of nested neural networks, consisting of interconnected subnetworks. Analysis based on simplified mathematical models more appropriate for artificial electronic neural networks, partly applicable to biological neural networks. Nested structure allows for retrieval of individual subpatterns. Requires fewer wires and connection devices than fully connected networks, and allows for local reconstruction of damaged subnetworks without rewiring entire network.

  4. Interconnection networks

    DOEpatents

    Faber, V.; Moore, J.W.

    1988-06-20

    A network of interconnected processors is formed from a vertex symmetric graph selected from graphs GAMMA/sub d/(k) with degree d, diameter k, and (d + 1)exclamation/ (d /minus/ k + 1)exclamation processors for each d greater than or equal to k and GAMMA/sub d/(k, /minus/1) with degree d /minus/ 1, diameter k + 1, and (d + 1)exclamation/(d /minus/ k + 1)exclamation processors for each d greater than or equal to k greater than or equal to 4. Each processor has an address formed by one of the permutations from a predetermined sequence of letters chosen a selected number of letters at a time, and an extended address formed by appending to the address the remaining ones of the predetermined sequence of letters. A plurality of transmission channels is provided from each of the processors, where each processor has one less channel than the selected number of letters forming the sequence. Where a network GAMMA/sub d/(k, /minus/1) is provided, no processor has a channel connected to form an edge in a direction delta/sub 1/. Each of the channels has an identification number selected from the sequence of letters and connected from a first processor having a first extended address to a second processor having a second address formed from a second extended address defined by moving to the front of the first extended address the letter found in the position within the first extended address defined by the channel identification number. The second address is then formed by selecting the first elements of the second extended address corresponding to the selected number used to form the address permutations. 9 figs.

  5. The Appeal to Expert Opinion: Quantitative Support for a Bayesian Network Approach.

    PubMed

    Harris, Adam J L; Hahn, Ulrike; Madsen, Jens K; Hsu, Anne S

    2016-08-01

    The appeal to expert opinion is an argument form that uses the verdict of an expert to support a position or hypothesis. A previous scheme-based treatment of the argument form is formalized within a Bayesian network that is able to capture the critical aspects of the argument form, including the central considerations of the expert's expertise and trustworthiness. We propose this as an appropriate normative framework for the argument form, enabling the development and testing of quantitative predictions as to how people evaluate this argument, suggesting that such an approach might be beneficial to argumentation research generally. We subsequently present two experiments as an example of the potential for future research in this vein, demonstrating that participants' quantitative ratings of the convincingness of a proposition that has been supported with an appeal to expert opinion were broadly consistent with the predictions of the Bayesian model.

  6. Classification and Prediction of Traffic Flow Based on Real Data Using Neural Networks

    NASA Astrophysics Data System (ADS)

    Pamuła, Teresa

    2012-12-01

    This paper presents a method of classification of time series of traffic flow, on the section of the main road leading into the city of Gliwice. Video detectors recorded traffic volume data was used, covering the period of one year in 5-minute intervals - from June 2011 to May 2012. In order to classify the data a statistical analysis was performed, which resulted in the proposition of splitting the daily time series into four classes. The series were smoothed to obtain hourly flow rates. The classification was performed using neural networks with different structures and using a variable number of input data. The purpose of classification is the prediction of traffic flow rates in the afternoon basing on the morning traffic and the assessment of daily traffic volumes for a particular day of the week. The results can be utilized by intelligent urban traffic management systems.

  7. Robustness of networks of networks with degree-degree correlation

    NASA Astrophysics Data System (ADS)

    Min, Byungjoon; Canals, Santiago; Makse, Hernan

    Many real-world complex systems ranging from critical infrastructure and transportation networks to living systems including brain and cellular networks are not formed by an isolated network but by a network of networks. Randomly coupled networks with interdependency between different networks may easily result in abrupt collapse. Here, we seek a possible explanation of stable functioning in natural networks of networks including functional brain networks. Specifically, we analyze the robustness of networks of networks focused on one-to-many interconnections between different networks and degree-degree correlation. Implication of the network robustness on functional brain networks of rats is also discussed.

  8. Animal transportation networks.

    PubMed

    Perna, Andrea; Latty, Tanya

    2014-11-01

    Many group-living animals construct transportation networks of trails, galleries and burrows by modifying the environment to facilitate faster, safer or more efficient movement. Animal transportation networks can have direct influences on the fitness of individuals, whereas the shape and structure of transportation networks can influence community dynamics by facilitating contacts between different individuals and species. In this review, we discuss three key areas in the study of animal transportation networks: the topological properties of networks, network morphogenesis and growth, and the behaviour of network users. We present a brief primer on elements of network theory, and then discuss the different ways in which animal groups deal with the fundamental trade-off between the competing network properties of travel efficiency, robustness and infrastructure cost. We consider how the behaviour of network users can impact network efficiency, and call for studies that integrate both network topology and user behaviour. We finish with a prospectus for future research.

  9. Animal transportation networks

    PubMed Central

    Perna, Andrea; Latty, Tanya

    2014-01-01

    Many group-living animals construct transportation networks of trails, galleries and burrows by modifying the environment to facilitate faster, safer or more efficient movement. Animal transportation networks can have direct influences on the fitness of individuals, whereas the shape and structure of transportation networks can influence community dynamics by facilitating contacts between different individuals and species. In this review, we discuss three key areas in the study of animal transportation networks: the topological properties of networks, network morphogenesis and growth, and the behaviour of network users. We present a brief primer on elements of network theory, and then discuss the different ways in which animal groups deal with the fundamental trade-off between the competing network properties of travel efficiency, robustness and infrastructure cost. We consider how the behaviour of network users can impact network efficiency, and call for studies that integrate both network topology and user behaviour. We finish with a prospectus for future research. PMID:25165598

  10. The deep space network

    NASA Technical Reports Server (NTRS)

    1977-01-01

    Presented is Deep Space Network (DSN) progress in flight project support, tracking and data acquisition (TDA) research and technology, network engineering, hardware and software implementation, and operations.

  11. The deep space network

    NASA Technical Reports Server (NTRS)

    1975-01-01

    Summaries are given of Deep Space Network progress in flight project support, tracking and data acquisition research and technology, network engineering, hardware and software implementation, and operations.

  12. Structural and effective connectivity reveals potential network-based influences on category-sensitive visual areas

    PubMed Central

    Furl, Nicholas

    2015-01-01

    Visual category perception is thought to depend on brain areas that respond specifically when certain categories are viewed. These category-sensitive areas are often assumed to be “modules” (with some degree of processing autonomy) and to act predominantly on feedforward visual input. This modular view can be complemented by a view that treats brain areas as elements within more complex networks and as influenced by network properties. This network-oriented viewpoint is emerging from studies using either diffusion tensor imaging to map structural connections or effective connectivity analyses to measure how their functional responses influence each other. This literature motivates several hypotheses that predict category-sensitive activity based on network properties. Large, long-range fiber bundles such as inferior fronto-occipital, arcuate and inferior longitudinal fasciculi are associated with behavioral recognition and could play crucial roles in conveying backward influences on visual cortex from anterior temporal and frontal areas. Such backward influences could support top-down functions such as visual search and emotion-based visual modulation. Within visual cortex itself, areas sensitive to different categories appear well-connected (e.g., face areas connect to object- and motion sensitive areas) and their responses can be predicted by backward modulation. Evidence supporting these propositions remains incomplete and underscores the need for better integration of DTI and functional imaging. PMID:25999841

  13. Computer Networks and Networking: A Primer.

    ERIC Educational Resources Information Center

    Collins, Mauri P.

    1993-01-01

    Provides a basic introduction to computer networks and networking terminology. Topics addressed include modems; the Internet; TCP/IP (Transmission Control Protocol/Internet Protocol); transmission lines; Internet Protocol numbers; network traffic; Fidonet; file transfer protocol (FTP); TELNET; electronic mail; discussion groups; LISTSERV; USENET;…

  14. [Neuronal network].

    PubMed

    Langmeier, M; Maresová, D

    2005-01-01

    Function of the central nervous system is based on mutual relations among the nerve cells. Description of nerve cells and their processes, including their contacts was enabled by improvement of optical features of the microscope and by the development of impregnation techniques. It is associated with the name of Antoni van Leeuwenhoek (1632-1723), J. Ev. Purkyne (1787-1869), Camillo Golgi (1843-1926), and Ramón y Cajal (1852-1934). Principal units of the neuronal network are the synapses. The term synapse was introduced into neurophysiology by Charles Scott Sherrington (1857-1952). Majority of the interactions between nerve cells is mediated by neurotransmitters acting at the receptors of the postsynaptic membrane or at the autoreceptors of the presynaptic part of the synapse. Attachment of the vesicles to the presynaptic membrane and the release of the neurotransmitter into the synaptic cleft depend on the intracellular calcium concentration and on the presence of several proteins in the presynaptic element.

  15. Data center networks and network architecture

    NASA Astrophysics Data System (ADS)

    Esaki, Hiroshi

    2014-02-01

    This paper discusses and proposes the architectural framework, which is for data center networks. The data center networks require new technical challenges, and it would be good opportunity to change the functions, which are not need in current and future networks. Based on the observation and consideration on data center networks, this paper proposes; (i) Broadcast-free layer 2 network (i.e., emulation of broadcast at the end-node), (ii) Full-mesh point-to-point pipes, and (iii) IRIDES (Invitation Routing aDvertisement for path Engineering System).

  16. Network epidemiology and plant trade networks

    PubMed Central

    Pautasso, Marco; Jeger, Mike J.

    2014-01-01

    Models of epidemics in complex networks are improving our predictive understanding of infectious disease outbreaks. Nonetheless, applying network theory to plant pathology is still a challenge. This overview summarizes some key developments in network epidemiology that are likely to facilitate its application in the study and management of plant diseases. Recent surveys have provided much-needed datasets on contact patterns and human mobility in social networks, but plant trade networks are still understudied. Human (and plant) mobility levels across the planet are unprecedented—there is thus much potential in the use of network theory by plant health authorities and researchers. Given the directed and hierarchical nature of plant trade networks, there is a need for plant epidemiologists to further develop models based on undirected and homogeneous networks. More realistic plant health scenarios would also be obtained by developing epidemic models in dynamic, rather than static, networks. For plant diseases spread by the horticultural and ornamental trade, there is the challenge of developing spatio-temporal epidemic simulations integrating network data. The use of network theory in plant epidemiology is a promising avenue and could contribute to anticipating and preventing plant health emergencies such as European ash dieback. PMID:24790128

  17. Network epidemiology and plant trade networks.

    PubMed

    Pautasso, Marco; Jeger, Mike J

    2014-01-01

    Models of epidemics in complex networks are improving our predictive understanding of infectious disease outbreaks. Nonetheless, applying network theory to plant pathology is still a challenge. This overview summarizes some key developments in network epidemiology that are likely to facilitate its application in the study and management of plant diseases. Recent surveys have provided much-needed datasets on contact patterns and human mobility in social networks, but plant trade networks are still understudied. Human (and plant) mobility levels across the planet are unprecedented-there is thus much potential in the use of network theory by plant health authorities and researchers. Given the directed and hierarchical nature of plant trade networks, there is a need for plant epidemiologists to further develop models based on undirected and homogeneous networks. More realistic plant health scenarios would also be obtained by developing epidemic models in dynamic, rather than static, networks. For plant diseases spread by the horticultural and ornamental trade, there is the challenge of developing spatio-temporal epidemic simulations integrating network data. The use of network theory in plant epidemiology is a promising avenue and could contribute to anticipating and preventing plant health emergencies such as European ash dieback.

  18. Natural language acquisition in large scale neural semantic networks

    NASA Astrophysics Data System (ADS)

    Ealey, Douglas

    This thesis puts forward the view that a purely signal- based approach to natural language processing is both plausible and desirable. By questioning the veracity of symbolic representations of meaning, it argues for a unified, non-symbolic model of knowledge representation that is both biologically plausible and, potentially, highly efficient. Processes to generate a grounded, neural form of this model-dubbed the semantic filter-are discussed. The combined effects of local neural organisation, coincident with perceptual maturation, are used to hypothesise its nature. This theoretical model is then validated in light of a number of fundamental neurological constraints and milestones. The mechanisms of semantic and episodic development that the model predicts are then used to explain linguistic properties, such as propositions and verbs, syntax and scripting. To mimic the growth of locally densely connected structures upon an unbounded neural substrate, a system is developed that can grow arbitrarily large, data- dependant structures composed of individual self- organising neural networks. The maturational nature of the data used results in a structure in which the perception of concepts is refined by the networks, but demarcated by subsequent structure. As a consequence, the overall structure shows significant memory and computational benefits, as predicted by the cognitive and neural models. Furthermore, the localised nature of the neural architecture also avoids the increasing error sensitivity and redundancy of traditional systems as the training domain grows. The semantic and episodic filters have been demonstrated to perform as well, or better, than more specialist networks, whilst using significantly larger vocabularies, more complex sentence forms and more natural corpora.

  19. Engineering technology for networks

    NASA Technical Reports Server (NTRS)

    Paul, Arthur S.; Benjamin, Norman

    1991-01-01

    Space Network (SN) modeling and evaluation are presented. The following tasks are included: Network Modeling (developing measures and metrics for SN, modeling of the Network Control Center (NCC), using knowledge acquired from the NCC to model the SNC, and modeling the SN); and Space Network Resource scheduling.

  20. Networked Resources: Usenet.

    ERIC Educational Resources Information Center

    Nickerson, Gord

    1992-01-01

    Describes the development of Usenet, the User's Network, a computer network that distributes group discussions (newsgroups) on different topics. Network News software is described, the rapid growth in popularity and heavy network traffic is discussed, and a hierarchical classification scheme to limit the amount of information for users is…

  1. Damselfly Network Simulator

    SciTech Connect

    2014-04-01

    Damselfly is a model-based parallel network simulator. It can simulate communication patterns of High Performance Computing applications on different network topologies. It outputs steady-state network traffic for a communication pattern, which can help in studying network congestion and its impact on performance.

  2. Coupled adaptive complex networks.

    PubMed

    Shai, S; Dobson, S

    2013-04-01

    Adaptive networks, which combine topological evolution of the network with dynamics on the network, are ubiquitous across disciplines. Examples include technical distribution networks such as road networks and the internet, natural and biological networks, and social science networks. These networks often interact with or depend upon other networks, resulting in coupled adaptive networks. In this paper we study susceptible-infected-susceptible (SIS) epidemic dynamics on coupled adaptive networks, where susceptible nodes are able to avoid contact with infected nodes by rewiring their intranetwork connections. However, infected nodes can pass the disease through internetwork connections, which do not change with time: The dependencies between the coupled networks remain constant. We develop an analytical formalism for these systems and validate it using extensive numerical simulation. We find that stability is increased by increasing the number of internetwork links, in the sense that the range of parameters over which both endemic and healthy states coexist (both states are reachable depending on the initial conditions) becomes smaller. Finally, we find a new stable state that does not appear in the case of a single adaptive network but only in the case of weakly coupled networks, in which the infection is endemic in one network but neither becomes endemic nor dies out in the other. Instead, it persists only at the nodes that are coupled to nodes in the other network through internetwork links. We speculate on the implications of these findings. PMID:23679478

  3. Coupled adaptive complex networks

    NASA Astrophysics Data System (ADS)

    Shai, S.; Dobson, S.

    2013-04-01

    Adaptive networks, which combine topological evolution of the network with dynamics on the network, are ubiquitous across disciplines. Examples include technical distribution networks such as road networks and the internet, natural and biological networks, and social science networks. These networks often interact with or depend upon other networks, resulting in coupled adaptive networks. In this paper we study susceptible-infected-susceptible (SIS) epidemic dynamics on coupled adaptive networks, where susceptible nodes are able to avoid contact with infected nodes by rewiring their intranetwork connections. However, infected nodes can pass the disease through internetwork connections, which do not change with time: The dependencies between the coupled networks remain constant. We develop an analytical formalism for these systems and validate it using extensive numerical simulation. We find that stability is increased by increasing the number of internetwork links, in the sense that the range of parameters over which both endemic and healthy states coexist (both states are reachable depending on the initial conditions) becomes smaller. Finally, we find a new stable state that does not appear in the case of a single adaptive network but only in the case of weakly coupled networks, in which the infection is endemic in one network but neither becomes endemic nor dies out in the other. Instead, it persists only at the nodes that are coupled to nodes in the other network through internetwork links. We speculate on the implications of these findings.

  4. Networking the Classroom.

    ERIC Educational Resources Information Center

    Stencel, Sandra, Ed.; And Others

    1995-01-01

    This issue of "CQ Researcher" examines the theme of computer networking in the classroom and discusses uses past and present. It begins with an essay by Christopher Conte that discusses: "Does computer networking really enhance learning? Are teachers adequately prepared to take advantage of computer networking? Will computer networking promote…

  5. Special Section on Networking.

    ERIC Educational Resources Information Center

    McInnis, Noel; And Others

    1984-01-01

    Examines how networking can be used to manage a changing world, how computer networking alleviates many problems encountered in more traditional communications forums, what a networking group can accomplish, and the potential of learning networks to become a nationwide movement, offering high-quality education at no charge. (RM)

  6. Designing Secure Library Networks.

    ERIC Educational Resources Information Center

    Breeding, Michael

    1997-01-01

    Focuses on designing a library network to maximize security. Discusses UNIX and file servers; connectivity to campus, corporate networks and the Internet; separation of staff from public servers; controlling traffic; the threat of network sniffers; hubs that eliminate eavesdropping; dividing the network into subnets; Switched Ethernet;…

  7. Networks in Cell Biology

    NASA Astrophysics Data System (ADS)

    Buchanan, Mark; Caldarelli, Guido; De Los Rios, Paolo; Rao, Francesco; Vendruscolo, Michele

    2010-05-01

    Introduction; 1. Network views of the cell Paolo De Los Rios and Michele Vendruscolo; 2. Transcriptional regulatory networks Sarath Chandra Janga and M. Madan Babu; 3. Transcription factors and gene regulatory networks Matteo Brilli, Elissa Calistri and Pietro Lió; 4. Experimental methods for protein interaction identification Peter Uetz, Björn Titz, Seesandra V. Rajagopala and Gerard Cagney; 5. Modeling protein interaction networks Francesco Rao; 6. Dynamics and evolution of metabolic networks Daniel Segré; 7. Hierarchical modularity in biological networks: the case of metabolic networks Erzsébet Ravasz Regan; 8. Signalling networks Gian Paolo Rossini; Appendix 1. Complex networks: from local to global properties D. Garlaschelli and G. Caldarelli; Appendix 2. Modelling the local structure of networks D. Garlaschelli and G. Caldarelli; Appendix 3. Higher-order topological properties S. Ahnert, T. Fink and G. Caldarelli; Appendix 4. Elementary mathematical concepts A. Gabrielli and G. Caldarelli; References.

  8. Control of Multilayer Networks

    PubMed Central

    Menichetti, Giulia; Dall’Asta, Luca; Bianconi, Ginestra

    2016-01-01

    The controllability of a network is a theoretical problem of relevance in a variety of contexts ranging from financial markets to the brain. Until now, network controllability has been characterized only on isolated networks, while the vast majority of complex systems are formed by multilayer networks. Here we build a theoretical framework for the linear controllability of multilayer networks by mapping the problem into a combinatorial matching problem. We found that correlating the external signals in the different layers can significantly reduce the multiplex network robustness to node removal, as it can be seen in conjunction with a hybrid phase transition occurring in interacting Poisson networks. Moreover we observe that multilayer networks can stabilize the fully controllable multiplex network configuration that can be stable also when the full controllability of the single network is not stable. PMID:26869210

  9. Electronic Neural Networks

    NASA Technical Reports Server (NTRS)

    Thakoor, Anil

    1990-01-01

    Viewgraphs on electronic neural networks for space station are presented. Topics covered include: electronic neural networks; electronic implementations; VLSI/thin film hybrid hardware for neurocomputing; computations with analog parallel processing; features of neuroprocessors; applications of neuroprocessors; neural network hardware for terrain trafficability determination; a dedicated processor for path planning; neural network system interface; neural network for robotic control; error backpropagation algorithm for learning; resource allocation matrix; global optimization neuroprocessor; and electrically programmable read only thin-film synaptic array.

  10. Minimal Increase Network Coding for Dynamic Networks.

    PubMed

    Zhang, Guoyin; Fan, Xu; Wu, Yanxia

    2016-01-01

    Because of the mobility, computing power and changeable topology of dynamic networks, it is difficult for random linear network coding (RLNC) in static networks to satisfy the requirements of dynamic networks. To alleviate this problem, a minimal increase network coding (MINC) algorithm is proposed. By identifying the nonzero elements of an encoding vector, it selects blocks to be encoded on the basis of relationship between the nonzero elements that the controls changes in the degrees of the blocks; then, the encoding time is shortened in a dynamic network. The results of simulations show that, compared with existing encoding algorithms, the MINC algorithm provides reduced computational complexity of encoding and an increased probability of delivery. PMID:26867211

  11. Minimal Increase Network Coding for Dynamic Networks.

    PubMed

    Zhang, Guoyin; Fan, Xu; Wu, Yanxia

    2016-01-01

    Because of the mobility, computing power and changeable topology of dynamic networks, it is difficult for random linear network coding (RLNC) in static networks to satisfy the requirements of dynamic networks. To alleviate this problem, a minimal increase network coding (MINC) algorithm is proposed. By identifying the nonzero elements of an encoding vector, it selects blocks to be encoded on the basis of relationship between the nonzero elements that the controls changes in the degrees of the blocks; then, the encoding time is shortened in a dynamic network. The results of simulations show that, compared with existing encoding algorithms, the MINC algorithm provides reduced computational complexity of encoding and an increased probability of delivery.

  12. Minimal Increase Network Coding for Dynamic Networks

    PubMed Central

    Wu, Yanxia

    2016-01-01

    Because of the mobility, computing power and changeable topology of dynamic networks, it is difficult for random linear network coding (RLNC) in static networks to satisfy the requirements of dynamic networks. To alleviate this problem, a minimal increase network coding (MINC) algorithm is proposed. By identifying the nonzero elements of an encoding vector, it selects blocks to be encoded on the basis of relationship between the nonzero elements that the controls changes in the degrees of the blocks; then, the encoding time is shortened in a dynamic network. The results of simulations show that, compared with existing encoding algorithms, the MINC algorithm provides reduced computational complexity of encoding and an increased probability of delivery. PMID:26867211

  13. Networking: challenges for network centric operations

    NASA Astrophysics Data System (ADS)

    Stotts, Larry B.; Allen, John G.

    2004-11-01

    This paper examines some of the challenges facing the community in providing radio communications to enable information systems for military operations. We believe that much of the on-going/completed work is necessary, but not sufficient, to provide the military Network Centric Operations, which integrates military"s network centric enterprise with network centric warfare. Additional issues need to be addressed to better support battle commanders as well as decider-sensor-effecter linkages. We discuss a possible way ahead.

  14. Robustness of a Network of Networks

    NASA Astrophysics Data System (ADS)

    Gao, Jianxi; Buldyrev, Sergey V.; Havlin, Shlomo; Stanley, H. Eugene

    2011-11-01

    Network research has been focused on studying the properties of a single isolated network, which rarely exists. We develop a general analytical framework for studying percolation of n interdependent networks. We illustrate our analytical solutions for three examples: (i) For any tree of n fully dependent Erdős-Rényi (ER) networks, each of average degree k¯, we find that the giant component is P∞=p[1-exp⁡(-k¯P∞)]n where 1-p is the initial fraction of removed nodes. This general result coincides for n=1 with the known second-order phase transition for a single network. For any n>1 cascading failures occur and the percolation becomes an abrupt first-order transition. (ii) For a starlike network of n partially interdependent ER networks, P∞ depends also on the topology—in contrast to case (i). (iii) For a looplike network formed by n partially dependent ER networks, P∞ is independent of n.

  15. Parallel Consensual Neural Networks

    NASA Technical Reports Server (NTRS)

    Benediktsson, J. A.; Sveinsson, J. R.; Ersoy, O. K.; Swain, P. H.

    1993-01-01

    A new neural network architecture is proposed and applied in classification of remote sensing/geographic data from multiple sources. The new architecture is called the parallel consensual neural network and its relation to hierarchical and ensemble neural networks is discussed. The parallel consensual neural network architecture is based on statistical consensus theory. The input data are transformed several times and the different transformed data are applied as if they were independent inputs and are classified using stage neural networks. Finally, the outputs from the stage networks are then weighted and combined to make a decision. Experimental results based on remote sensing data and geographic data are given. The performance of the consensual neural network architecture is compared to that of a two-layer (one hidden layer) conjugate-gradient backpropagation neural network. The results with the proposed neural network architecture compare favorably in terms of classification accuracy to the backpropagation method.

  16. Translated chemical reaction networks.

    PubMed

    Johnston, Matthew D

    2014-05-01

    Many biochemical and industrial applications involve complicated networks of simultaneously occurring chemical reactions. Under the assumption of mass action kinetics, the dynamics of these chemical reaction networks are governed by systems of polynomial ordinary differential equations. The steady states of these mass action systems have been analyzed via a variety of techniques, including stoichiometric network analysis, deficiency theory, and algebraic techniques (e.g., Gröbner bases). In this paper, we present a novel method for characterizing the steady states of mass action systems. Our method explicitly links a network's capacity to permit a particular class of steady states, called toric steady states, to topological properties of a generalized network called a translated chemical reaction network. These networks share their reaction vectors with their source network but are permitted to have different complex stoichiometries and different network topologies. We apply the results to examples drawn from the biochemical literature.

  17. Properties of switch-like bioregulatory networks studied by simulation of the hypoxia response control system.

    PubMed

    Kohn, Kurt W; Riss, Joseph; Aprelikova, Olga; Weinstein, John N; Pommier, Yves; Barrett, J Carl

    2004-07-01

    A complex bioregulatory network could be more easily comprehended if its essential function could be described by a small "core" subsystem, and if its response characteristics were switch-like. We tested this proposition by simulation studies of the hypoxia response control network. We hypothesized that a small subsystem governs the basics of the cellular response to hypoxia and that this response has a sharp oxygen-dependent transition. A molecular interaction map of the network was prepared, and an evolutionarily conserved core subsystem was extracted that could control the activity of hypoxia response promoter elements on the basis of oxygen concentration. The core subsystem included the hypoxia-inducible transcription factor (HIFalpha:ARNT heterodimer), proline hydroxylase, and the von Hippel-Lindau protein. Simulation studies showed that the same core subsystem can exhibit switch-like responses both to oxygen level and to HIFalpha synthesis rate, thus suggesting a mechanism for hypoxia response promoter element-dependent responses common to both hypoxia and growth factor signaling. The studies disclosed the mechanism responsible for the sharp transitions. We show how parameter sets giving switch-like behavior can be found and how this type of behavior provides a foundation for quantitative studies in cells. PMID:15107465

  18. Satellite networks for education

    NASA Technical Reports Server (NTRS)

    Singh, J. P.; Morgan, R. P.; Rosenbaum, F. J.

    1972-01-01

    Satellite based educational networking is discussed with particular attention given to the potential uses of communications satellites to help meet educational needs in the United states. Four major subject areas were covered; (1) characteristics and structure of networks, (2) definition of pressures within educational establishment that provide motivation for various types of networks, (3) examination of current educational networking status for educational radio and television, instructional television fixed services, inter- and intra-state educational communication networks, computer networks, and cable television for education, and (4) identification of possible satellite based educational telecommunication services and three alternatives for implementing educational satellite systems.

  19. Local area networking: Ames centerwide network

    NASA Technical Reports Server (NTRS)

    Price, Edwin

    1988-01-01

    A computer network can benefit the user by making his/her work quicker and easier. A computer network is made up of seven different layers with the lowest being the hardware, the top being the user, and the middle being the software. These layers are discussed.

  20. Network II Database

    1994-11-07

    The Oak Ridge National Laboratory (ORNL) Rail and Barge Network II Database is a representation of the rail and barge system of the United States. The network is derived from the Federal Rail Administration (FRA) rail database.

  1. Integrated digital networks

    NASA Astrophysics Data System (ADS)

    Schwartz, M.; Stern, T.; Lazar, A.

    1984-09-01

    The basic problem described in this document is that of transmitting mixtures of traffic of disparate types over a variety of communication networks. Typical examples include the transmission of interactive data, long streams of data (e.g., file transfers), voice, video, and facsimile in an integrated fashion. Network types include local area networks, metropolitan area networks, large geographically-dispersed terrestrial networks, and satellite networks. Ongoing standards work in the C CITT, supported by telephone administrations worldwide, has focused on the concept of Integrated Services Digital Networks (ISDN) toward which worldwide telecommunications will be moving. Computer manufacturers with a great deal of interest in communications (IBM is a prominent example) have begun to devote considerable effort as well to the concept of traffic integration over networks.

  2. Social networks and schizophrenia.

    PubMed

    Beels, C C

    1979-01-01

    This artical begins with an introduction to social networks research and its practical importance in the understanding and treatment of schizophrenia, and concludes with a consideration of the experience, the phenomenology, of schizophrenia, from a social network point of view.

  3. The Networked Classroom

    ERIC Educational Resources Information Center

    Roschelle, Jeremy; Penuel, William R.; Abrahamson, Louis

    2004-01-01

    Classroom network requires every student to think actively, which enhances student participation in mathematics and science. Classroom-specific networks use software designed to enhance communication between teacher and students.

  4. Bladder Cancer Advocacy Network

    MedlinePlus

    ... future bladder cancer research through the Patient Survey Network. Read More... The JPB Foundation 2016 Bladder Cancer ... 2016 Young Investigator Awardees The Bladder Cancer Advocacy Network (BCAN) has announced the recipients of the 2016 ...

  5. Networking and Institutional Planning.

    ERIC Educational Resources Information Center

    Riggs, Donald E.

    1987-01-01

    Explores the impact of networks and shared library resources on the library planning process. Environmental scanning techniques, the need for cooperative planning, and the formulation of strategies to achieve networking goals are discussed. (CLB)

  6. Virtualized Network Control (VNC)

    SciTech Connect

    Lehman, Thomas; Guok, Chin; Ghani, Nasir

    2013-01-31

    The focus of this project was on the development of a "Network Service Plane" as an abstraction model for the control and provisioning of multi-layer networks. The primary motivation for this work were the requirements of next generation networked applications which will need to access advanced networking as a first class resource at the same level as compute and storage resources. A new class of "Intelligent Network Services" were defined in order to facilitate the integration of advanced network services into application specific workflows. This new class of network services are intended to enable real-time interaction between the application co-scheduling algorithms and the network for the purposes of workflow planning, real-time resource availability identification, scheduling, and provisioning actions.

  7. The deep space network

    NASA Technical Reports Server (NTRS)

    1977-01-01

    A Deep Space Network progress report is presented dealing with in flight project support, tracking and data acquisition research and technology, network engineering, hardware and software implementation, and operations.

  8. Class network routing

    DOEpatents

    Bhanot, Gyan; Blumrich, Matthias A.; Chen, Dong; Coteus, Paul W.; Gara, Alan G.; Giampapa, Mark E.; Heidelberger, Philip; Steinmacher-Burow, Burkhard D.; Takken, Todd E.; Vranas, Pavlos M.

    2009-09-08

    Class network routing is implemented in a network such as a computer network comprising a plurality of parallel compute processors at nodes thereof. Class network routing allows a compute processor to broadcast a message to a range (one or more) of other compute processors in the computer network, such as processors in a column or a row. Normally this type of operation requires a separate message to be sent to each processor. With class network routing pursuant to the invention, a single message is sufficient, which generally reduces the total number of messages in the network as well as the latency to do a broadcast. Class network routing is also applied to dense matrix inversion algorithms on distributed memory parallel supercomputers with hardware class function (multicast) capability. This is achieved by exploiting the fact that the communication patterns of dense matrix inversion can be served by hardware class functions, which results in faster execution times.

  9. The deep space network

    NASA Technical Reports Server (NTRS)

    1979-01-01

    Progress is reported in flight project support, tracking and data acquisition research and technology, network engineering, hardware and software implementation, and operations. The functions and facilities of the Deep Space Network are emphasized.

  10. The deep space network

    NASA Technical Reports Server (NTRS)

    1977-01-01

    The facilities, programming system, and monitor and control system for the deep space network are described. Ongoing planetary and interplanetary flight projects are reviewed, along with tracking and ground-based navigation, communications, and network and facility engineering.

  11. The deep space network

    NASA Technical Reports Server (NTRS)

    1979-01-01

    A report is given of the Deep Space Networks progress in (1) flight project support, (2) tracking and data acquisition research and technology, (3) network engineering, (4) hardware and software implementation, and (5) operations.

  12. The deep space network

    NASA Technical Reports Server (NTRS)

    1980-01-01

    The functions and facilities of the Deep Space Network are considered. Progress in flight project support, tracking and data acquisition research and technology, network engineering, hardware and software implementation, and operations is reported.

  13. Local network assessment

    NASA Astrophysics Data System (ADS)

    Glen, D. V.

    1985-04-01

    Local networks, related standards activities of the Institute of Electrical and Electronics Engineers the American National Standards Institute and other elements are presented. These elements include: (1) technology choices such as topology, transmission media, and access protocols; (2) descriptions of standards for the 802 local area networks (LAN's); high speed local networks (HSLN's) and military specification local networks; and (3) intra- and internetworking using bridges and gateways with protocols Interconnection (OSI) reference model. The convergence of LAN/PBX technology is also described.

  14. Electronic Networking. ERIC Digest.

    ERIC Educational Resources Information Center

    Tucker, Susan

    This digest discusses several aspects of electronic networking, including network functions, implementation, and applications in education. Electronic networking is defined as including the four basic services of electronic mail (E-mail), electronic "bulletin boards," teleconferencing, and online databases, and an overview of these four functions…

  15. Spanish Museum Libraries Network.

    ERIC Educational Resources Information Center

    Lopez de Prado, Rosario

    This paper describes the creation of an automated network of museum libraries in Spain. The only way in which the specialized libraries in the world today can continue to be active and to offer valid information is to automate the service they offer, and create network libraries with cooperative plans. The network can be configured with different…

  16. Multimedia Networks: Mission Impossible?

    ERIC Educational Resources Information Center

    Weiss, Andrew M.

    1996-01-01

    Running multimedia on a network, often difficult because of the memory and processing power required, is becoming easier thanks to new protocols and products. Those developing network design criteria may wish to consider making use of Fast Ethernet, Asynchronous Transfer Method (ATM), switches, "fat pipes", additional network segmentation, and…

  17. The Network Classroom.

    ERIC Educational Resources Information Center

    Maule, R. William

    1993-01-01

    Discussion of the role of new computer communications technologies in education focuses on modern networking systems, including fiber distributed data interface and Integrated Services Digital Network; strategies for implementing networked-based communication; and public online information resources for the classroom, including Bitnet, Internet,…

  18. Equilibrium games in networks

    NASA Astrophysics Data System (ADS)

    Li, Angsheng; Zhang, Xiaohui; Pan, Yicheng; Peng, Pan

    2014-12-01

    It seems a universal phenomenon of networks that the attacks on a small number of nodes by an adversary player Alice may generate a global cascading failure of the networks. It has been shown (Li et al., 2013) that classic scale-free networks (Barabási and Albert, 1999, Barabási, 2009) are insecure against attacks of as small as O(logn) many nodes. This poses a natural and fundamental question: Can we introduce a second player Bob to prevent Alice from global cascading failure of the networks? We proposed a game in networks. We say that a network has an equilibrium game if the second player Bob has a strategy to balance the cascading influence of attacks by the adversary player Alice. It was shown that networks of the preferential attachment model (Barabási and Albert, 1999) fail to have equilibrium games, that random graphs of the Erdös-Rényi model (Erdös and Rényi, 1959, Erdös and Rényi, 1960) have, for which randomness is the mechanism, and that homophyly networks (Li et al., 2013) have equilibrium games, for which homophyly and preferential attachment are the underlying mechanisms. We found that some real networks have equilibrium games, but most real networks fail to have. We anticipate that our results lead to an interesting new direction of network theory, that is, equilibrium games in networks.

  19. Networking Brown University.

    ERIC Educational Resources Information Center

    Beckham, Bonnie

    1989-01-01

    Assesses BRUNET, a campuswide network that links more than 100 academic and administrative buildings and 40 dormitories. Notes a key element is hierarchical network management and support. Discusses the deployment, security, and use of four networking spheres in the system. (MVL)

  20. Flexible embedding of networks

    NASA Astrophysics Data System (ADS)

    Fernandez-Gracia, Juan; Buckee, Caroline; Onnela, Jukka-Pekka

    We introduce a model for embedding one network into another, focusing on the case where network A is much bigger than network B. Nodes from network A are assigned to the nodes in network B using an algorithm where we control the extent of localization of node placement in network B using a single parameter. Starting from an unassigned node in network A, called the source node, we first map this node to a randomly chosen node in network B, called the target node. We then assign the neighbors of the source node to the neighborhood of the target node using a random walk based approach. To assign each neighbor of the source node to one of the nodes in network B, we perform a random walk starting from the target node with stopping probability α. We repeat this process until all nodes in network A have been mapped to the nodes of network B. The simplicity of the model allows us to calculate key quantities of interest in closed form. By varying the parameter α, we are able to produce embeddings from very local (α = 1) to very global (α --> 0). We show how our calculations fit the simulated results, and we apply the model to study how social networks are embedded in geography and how the neurons of C. Elegans are embedded in the surrounding volume.

  1. Networks of Schools.

    ERIC Educational Resources Information Center

    McMeekin, Robert W.

    2003-01-01

    Suggests that networks of schools help improve school performance, and that one reason some networks are successful is that they promote the creation of sound institutional environments in member schools. Describes three such networks: the Matte Schools of Santiago, Chile; the Fe y Alegria schools in Latin American countries; and the Accelerated…

  2. Metallic nanowire networks

    DOEpatents

    Song, Yujiang; Shelnutt, John A.

    2012-11-06

    A metallic nanowire network synthesized using chemical reduction of a metal ion source by a reducing agent in the presence of a soft template comprising a tubular inverse micellar network. The network of interconnected polycrystalline nanowires has a very high surface-area/volume ratio, which makes it highly suitable for use in catalytic applications.

  3. Foundations of neural networks

    SciTech Connect

    Simpson, P.K.

    1994-12-31

    Building intelligent systems that can model human behavior has captured the attention of the world for years. So, it is not surprising that a technology such as neural networks has generated great interest. This paper will provide an evolutionary introduction to neural networks by beginning with the key elements and terminology of neural networks, and developing the topologies, learning laws, and recall dynamics from this infrastructure. The perspective taken in this paper is largely that of an engineer, emphasizing the application potential of neural networks and drawing comparisons with other techniques that have similar motivations. As such, mathematics will be relied upon in many of the discussions to make points as precise as possible. The paper begins with a review of what neural networks are and why they are so appealing. A typical neural network is immediately introduced to illustrate several of the key features. With this network as a reference, the evolutionary introduction to neural networks is then pursued. The fundamental elements of a neural network, such as input and output patterns, processing element, connections, and threshold operations, are described, followed by descriptions of neural network topologies, learning algorithms, and recall dynamics. A taxonomy of neural networks is presented that uses two of the key characteristics of learning and recall. Finally, a comparison of neural networks and similar nonneural information processing methods is presented.

  4. Emergent Network Defense

    ERIC Educational Resources Information Center

    Crane, Earl Newell

    2013-01-01

    The research problem that inspired this effort is the challenge of managing the security of systems in large-scale heterogeneous networked environments. Human intervention is slow and limited: humans operate at much slower speeds than networked computer communications and there are few humans associated with each network. Enabling each node in the…

  5. Spatially embedded random networks.

    PubMed

    Barnett, L; Di Paolo, E; Bullock, S

    2007-11-01

    Many real-world networks analyzed in modern network theory have a natural spatial element; e.g., the Internet, social networks, neural networks, etc. Yet, aside from a comparatively small number of somewhat specialized and domain-specific studies, the spatial element is mostly ignored and, in particular, its relation to network structure disregarded. In this paper we introduce a model framework to analyze the mediation of network structure by spatial embedding; specifically, we model connectivity as dependent on the distance between network nodes. Our spatially embedded random networks construction is not primarily intended as an accurate model of any specific class of real-world networks, but rather to gain intuition for the effects of spatial embedding on network structure; nevertheless we are able to demonstrate, in a quite general setting, some constraints of spatial embedding on connectivity such as the effects of spatial symmetry, conditions for scale free degree distributions and the existence of small-world spatial networks. We also derive some standard structural statistics for spatially embedded networks and illustrate the application of our model framework with concrete examples. PMID:18233726

  6. Spatially embedded random networks

    NASA Astrophysics Data System (ADS)

    Barnett, L.; di Paolo, E.; Bullock, S.

    2007-11-01

    Many real-world networks analyzed in modern network theory have a natural spatial element; e.g., the Internet, social networks, neural networks, etc. Yet, aside from a comparatively small number of somewhat specialized and domain-specific studies, the spatial element is mostly ignored and, in particular, its relation to network structure disregarded. In this paper we introduce a model framework to analyze the mediation of network structure by spatial embedding; specifically, we model connectivity as dependent on the distance between network nodes. Our spatially embedded random networks construction is not primarily intended as an accurate model of any specific class of real-world networks, but rather to gain intuition for the effects of spatial embedding on network structure; nevertheless we are able to demonstrate, in a quite general setting, some constraints of spatial embedding on connectivity such as the effects of spatial symmetry, conditions for scale free degree distributions and the existence of small-world spatial networks. We also derive some standard structural statistics for spatially embedded networks and illustrate the application of our model framework with concrete examples.

  7. Calorimetry Network Program

    1998-01-30

    This is a Windows NT based program to run the SRTC designed calorimeters. The network version can communicate near real time data and final data values over the network. This version, due to network specifics, can function in a stand-alone operation also.

  8. Managing Knowledge Networks.

    ERIC Educational Resources Information Center

    Contractor, Noshir S.; Monge, Peter R.

    2002-01-01

    Describes a multitheoretical, multilevel (MTML) model to study the management of knowledge networks. Considers theoretical mechanisms for emergence of knowledge networks and presents empirical findings about the emergence of knowledge networks. Concludes that it is necessary to utilize MTML models to integrate multiple social and communication…

  9. Electronic neural networks

    SciTech Connect

    Howard, R.E.; Jackel, L.D.; Graf, H.P.

    1988-02-01

    The use of electronic neural networks to handle some complex computing problems is discussed. A simple neural model is shown and discussed in terms of its computational aspects. The use of electronic neural networks in machine pattern recognition and classification and in machine learning is examined. CMOS programmable networks are discussed. 15 references.

  10. Dominating Biological Networks

    PubMed Central

    Milenković, Tijana; Memišević, Vesna; Bonato, Anthony; Pržulj, Nataša

    2011-01-01

    Proteins are essential macromolecules of life that carry out most cellular processes. Since proteins aggregate to perform function, and since protein-protein interaction (PPI) networks model these aggregations, one would expect to uncover new biology from PPI network topology. Hence, using PPI networks to predict protein function and role of protein pathways in disease has received attention. A debate remains open about whether network properties of “biologically central (BC)” genes (i.e., their protein products), such as those involved in aging, cancer, infectious diseases, or signaling and drug-targeted pathways, exhibit some topological centrality compared to the rest of the proteins in the human PPI network. To help resolve this debate, we design new network-based approaches and apply them to get new insight into biological function and disease. We hypothesize that BC genes have a topologically central (TC) role in the human PPI network. We propose two different concepts of topological centrality. We design a new centrality measure to capture complex wirings of proteins in the network that identifies as TC those proteins that reside in dense extended network neighborhoods. Also, we use the notion of domination and find dominating sets (DSs) in the PPI network, i.e., sets of proteins such that every protein is either in the DS or is a neighbor of the DS. Clearly, a DS has a TC role, as it enables efficient communication between different network parts. We find statistically significant enrichment in BC genes of TC nodes and outperform the existing methods indicating that genes involved in key biological processes occupy topologically complex and dense regions of the network and correspond to its “spine” that connects all other network parts and can thus pass cellular signals efficiently throughout the network. To our knowledge, this is the first study that explores domination in the context of PPI networks. PMID:21887225

  11. Characteristics on hub networks of urban rail transit networks

    NASA Astrophysics Data System (ADS)

    Zhang, Jianhua; Wang, Shuliang; Zhang, Zhaojun; Zou, Kuansheng; Shu, Zhan

    2016-04-01

    This paper proposes an approach to extract the hub networks from urban rail transit networks, and analyzes the characteristics of the hub networks. Minsk metro and Shanghai metro networks are given to illustrate the feasibility and effectiveness of the presented method in this paper. By simulations, we discover that the hub networks of urban rail transit networks possess small-world property and scale-free property. Meanwhile, this paper shows that the hub networks are completely different from the corresponding metro networks. Moreover, we find that the hub network is a hierarchical network, and the root of hub network corresponds to the transfer station of metro network which is passed by the most lines in metro network, and the root controls the main characteristics of hub network. In other words, the transfer station corresponding to this root plays the most important role in the urban rail transit networks.

  12. Network fingerprint: a knowledge-based characterization of biomedical networks.

    PubMed

    Cui, Xiuliang; He, Haochen; He, Fuchu; Wang, Shengqi; Li, Fei; Bo, Xiaochen

    2015-08-26

    It can be difficult for biomedical researchers to understand complex molecular networks due to their unfamiliarity with the mathematical concepts employed. To represent molecular networks with clear meanings and familiar forms for biomedical researchers, we introduce a knowledge-based computational framework to decipher biomedical networks by making systematic comparisons to well-studied "basic networks". A biomedical network is characterized as a spectrum-like vector called "network fingerprint", which contains similarities to basic networks. This knowledge-based multidimensional characterization provides a more intuitive way to decipher molecular networks, especially for large-scale network comparisons and clustering analyses. As an example, we extracted network fingerprints of 44 disease networks in the Kyoto Encyclopedia of Genes and Genomes (KEGG) database. The comparisons among the network fingerprints of disease networks revealed informative disease-disease and disease-signaling pathway associations, illustrating that the network fingerprinting framework will lead to new approaches for better understanding of biomedical networks.

  13. A consensual neural network

    NASA Technical Reports Server (NTRS)

    Benediktsson, J. A.; Ersoy, O. K.; Swain, P. H.

    1991-01-01

    A neural network architecture called a consensual neural network (CNN) is proposed for the classification of data from multiple sources. Its relation to hierarchical and ensemble neural networks is discussed. CNN is based on the statistical consensus theory and uses nonlinearly transformed input data. The input data are transformed several times, and the different transformed data are applied as if they were independent inputs. The independent inputs are classified using stage neural networks and outputs from the stage networks are then weighted and combined to make a decision. Experimental results based on remote-sensing data and geographic data are given.

  14. Network structure of production

    PubMed Central

    Atalay, Enghin; Hortaçsu, Ali; Roberts, James; Syverson, Chad

    2011-01-01

    Complex social networks have received increasing attention from researchers. Recent work has focused on mechanisms that produce scale-free networks. We theoretically and empirically characterize the buyer–supplier network of the US economy and find that purely scale-free models have trouble matching key attributes of the network. We construct an alternative model that incorporates realistic features of firms’ buyer–supplier relationships and estimate the model’s parameters using microdata on firms’ self-reported customers. This alternative framework is better able to match the attributes of the actual economic network and aids in further understanding several important economic phenomena. PMID:21402924

  15. Networks Technology Conference

    NASA Technical Reports Server (NTRS)

    Tasaki, Keiji K. (Editor)

    1993-01-01

    The papers included in these proceedings represent the most interesting and current topics being pursued by personnel at GSFC's Networks Division and supporting contractors involved in Space, Ground, and Deep Space Network (DSN) technical work. Although 29 papers are represented in the proceedings, only 12 were presented at the conference because of space and time limitations. The proceedings are organized according to five principal technical areas of interest to the Networks Division: Project Management; Network Operations; Network Control, Scheduling, and Monitoring; Modeling and Simulation; and Telecommunications Engineering.

  16. Networks in cognitive science.

    PubMed

    Baronchelli, Andrea; Ferrer-i-Cancho, Ramon; Pastor-Satorras, Romualdo; Chater, Nick; Christiansen, Morten H

    2013-07-01

    Networks of interconnected nodes have long played a key role in Cognitive Science, from artificial neural networks to spreading activation models of semantic memory. Recently, however, a new Network Science has been developed, providing insights into the emergence of global, system-scale properties in contexts as diverse as the Internet, metabolic reactions, and collaborations among scientists. Today, the inclusion of network theory into Cognitive Sciences, and the expansion of complex-systems science, promises to significantly change the way in which the organization and dynamics of cognitive and behavioral processes are understood. In this paper, we review recent contributions of network theory at different levels and domains within the Cognitive Sciences.

  17. Network Characterization Service (NCS)

    SciTech Connect

    Jin, Guojun; Yang, George; Crowley, Brian; Agarwal, Deborah

    2001-06-06

    Distributed applications require information to effectively utilize the network. Some of the information they require is the current and maximum bandwidth, current and minimum latency, bottlenecks, burst frequency, and congestion extent. This type of information allows applications to determine parameters like optimal TCP buffer size. In this paper, we present a cooperative information-gathering tool called the network characterization service (NCS). NCS runs in user space and is used to acquire network information. Its protocol is designed for scalable and distributed deployment, similar to DNS. Its algorithms provide efficient, speedy and accurate detection of bottlenecks, especially dynamic bottlenecks. On current and future networks, dynamic bottlenecks do and will affect network performance dramatically.

  18. Neural-Network Simulator

    NASA Technical Reports Server (NTRS)

    Mitchell, Paul H.

    1991-01-01

    F77NNS (FORTRAN 77 Neural Network Simulator) computer program simulates popular back-error-propagation neural network. Designed to take advantage of vectorization when used on computers having this capability, also used on any computer equipped with ANSI-77 FORTRAN Compiler. Problems involving matching of patterns or mathematical modeling of systems fit class of problems F77NNS designed to solve. Program has restart capability so neural network solved in stages suitable to user's resources and desires. Enables user to customize patterns of connections between layers of network. Size of neural network F77NNS applied to limited only by amount of random-access memory available to user.

  19. Groundwater data network interoperability

    USGS Publications Warehouse

    Brodaric, Boyan; Booth, Nathaniel; Boisvert, Eric; Lucido, Jessica M.

    2016-01-01

    Water data networks are increasingly being integrated to answer complex scientific questions that often span large geographical areas and cross political borders. Data heterogeneity is a major obstacle that impedes interoperability within and between such networks. It is resolved here for groundwater data at five levels of interoperability, within a Spatial Data Infrastructure architecture. The result is a pair of distinct national groundwater data networks for the United States and Canada, and a combined data network in which they are interoperable. This combined data network enables, for the first time, transparent public access to harmonized groundwater data from both sides of the shared international border.

  20. A Neural Network Architecture For Rapid Model Indexing In Computer Vision Systems

    NASA Astrophysics Data System (ADS)

    Pawlicki, Ted

    1988-03-01

    of hierarchical indexing. (i.e. the specificity, adjunct, and parent indices) It supports the notion that multiple canonical views of an object may have to be stored in memory to enable its efficient identification. The use of variable fields in the state space vectors appears to keep the number of required nodes in the network down to a tractable number while imposing a semantic value on different areas of the state space. This semantic imposition supports an interface between the analogical aspects of neural networks and the propositional paradigms of symbolic processing.

  1. A Bayesian network approach to the database search problem in criminal proceedings

    PubMed Central

    2012-01-01

    Background The ‘database search problem’, that is, the strengthening of a case - in terms of probative value - against an individual who is found as a result of a database search, has been approached during the last two decades with substantial mathematical analyses, accompanied by lively debate and centrally opposing conclusions. This represents a challenging obstacle in teaching but also hinders a balanced and coherent discussion of the topic within the wider scientific and legal community. This paper revisits and tracks the associated mathematical analyses in terms of Bayesian networks. Their derivation and discussion for capturing probabilistic arguments that explain the database search problem are outlined in detail. The resulting Bayesian networks offer a distinct view on the main debated issues, along with further clarity. Methods As a general framework for representing and analyzing formal arguments in probabilistic reasoning about uncertain target propositions (that is, whether or not a given individual is the source of a crime stain), this paper relies on graphical probability models, in particular, Bayesian networks. This graphical probability modeling approach is used to capture, within a single model, a series of key variables, such as the number of individuals in a database, the size of the population of potential crime stain sources, and the rarity of the corresponding analytical characteristics in a relevant population. Results This paper demonstrates the feasibility of deriving Bayesian network structures for analyzing, representing, and tracking the database search problem. The output of the proposed models can be shown to agree with existing but exclusively formulaic approaches. Conclusions The proposed Bayesian networks allow one to capture and analyze the currently most well-supported but reputedly counter-intuitive and difficult solution to the database search problem in a way that goes beyond the traditional, purely formulaic expressions

  2. Emergent Complex Network Geometry

    NASA Astrophysics Data System (ADS)

    Wu, Zhihao; Menichetti, Giulia; Rahmede, Christoph; Bianconi, Ginestra

    2015-05-01

    Networks are mathematical structures that are universally used to describe a large variety of complex systems such as the brain or the Internet. Characterizing the geometrical properties of these networks has become increasingly relevant for routing problems, inference and data mining. In real growing networks, topological, structural and geometrical properties emerge spontaneously from their dynamical rules. Nevertheless we still miss a model in which networks develop an emergent complex geometry. Here we show that a single two parameter network model, the growing geometrical network, can generate complex network geometries with non-trivial distribution of curvatures, combining exponential growth and small-world properties with finite spectral dimensionality. In one limit, the non-equilibrium dynamical rules of these networks can generate scale-free networks with clustering and communities, in another limit planar random geometries with non-trivial modularity. Finally we find that these properties of the geometrical growing networks are present in a large set of real networks describing biological, social and technological systems.

  3. Cheaters in mutualism networks.

    PubMed

    Genini, Julieta; Morellato, L Patrícia C; Guimarães, Paulo R; Olesen, Jens M

    2010-08-23

    Mutualism-network studies assume that all interacting species are mutualistic partners and consider that all links are of one kind. However, the influence of different types of links, such as cheating links, on network organization remains unexplored. We studied two flower-visitation networks (Malpighiaceae and Bignoniaceae and their flower visitors), and divide the types of link into cheaters (i.e. robbers and thieves of flower rewards) and effective pollinators. We investigated if there were topological differences among networks with and without cheaters, especially with respect to nestedness and modularity. The Malpighiaceae network was nested, but not modular, and it was dominated by pollinators and had much fewer cheater species than Bignoniaceae network (28% versus 75%). The Bignoniaceae network was mainly a plant-cheater network, being modular because of the presence of pollen robbers and showing no nestedness. In the Malpighiaceae network, removal of cheaters had no major consequences for topology. In contrast, removal of cheaters broke down the modularity of the Bignoniaceae network. As cheaters are ubiquitous in all mutualisms, the results presented here show that they have a strong impact upon network topology.

  4. Network topology analysis.

    SciTech Connect

    Kalb, Jeffrey L.; Lee, David S.

    2008-01-01

    Emerging high-bandwidth, low-latency network technology has made network-based architectures both feasible and potentially desirable for use in satellite payload architectures. The selection of network topology is a critical component when developing these multi-node or multi-point architectures. This study examines network topologies and their effect on overall network performance. Numerous topologies were reviewed against a number of performance, reliability, and cost metrics. This document identifies a handful of good network topologies for satellite applications and the metrics used to justify them as such. Since often multiple topologies will meet the requirements of the satellite payload architecture under development, the choice of network topology is not easy, and in the end the choice of topology is influenced by both the design characteristics and requirements of the overall system and the experience of the developer.

  5. Internet protocol network mapper

    DOEpatents

    Youd, David W.; Colon III, Domingo R.; Seidl, Edward T.

    2016-02-23

    A network mapper for performing tasks on targets is provided. The mapper generates a map of a network that specifies the overall configuration of the network. The mapper inputs a procedure that defines how the network is to be mapped. The procedure specifies what, when, and in what order the tasks are to be performed. Each task specifies processing that is to be performed for a target to produce results. The procedure may also specify input parameters for a task. The mapper inputs initial targets that specify a range of network addresses to be mapped. The mapper maps the network by, for each target, executing the procedure to perform the tasks on the target. The results of the tasks represent the mapping of the network defined by the initial targets.

  6. Network planning under uncertainties

    NASA Astrophysics Data System (ADS)

    Ho, Kwok Shing; Cheung, Kwok Wai

    2008-11-01

    One of the main focuses for network planning is on the optimization of network resources required to build a network under certain traffic demand projection. Traditionally, the inputs to this type of network planning problems are treated as deterministic. In reality, the varying traffic requirements and fluctuations in network resources can cause uncertainties in the decision models. The failure to include the uncertainties in the network design process can severely affect the feasibility and economics of the network. Therefore, it is essential to find a solution that can be insensitive to the uncertain conditions during the network planning process. As early as in the 1960's, a network planning problem with varying traffic requirements over time had been studied. Up to now, this kind of network planning problems is still being active researched, especially for the VPN network design. Another kind of network planning problems under uncertainties that has been studied actively in the past decade addresses the fluctuations in network resources. One such hotly pursued research topic is survivable network planning. It considers the design of a network under uncertainties brought by the fluctuations in topology to meet the requirement that the network remains intact up to a certain number of faults occurring anywhere in the network. Recently, the authors proposed a new planning methodology called Generalized Survivable Network that tackles the network design problem under both varying traffic requirements and fluctuations of topology. Although all the above network planning problems handle various kinds of uncertainties, it is hard to find a generic framework under more general uncertainty conditions that allows a more systematic way to solve the problems. With a unified framework, the seemingly diverse models and algorithms can be intimately related and possibly more insights and improvements can be brought out for solving the problem. This motivates us to seek a

  7. Weighted multiplex networks.

    PubMed

    Menichetti, Giulia; Remondini, Daniel; Panzarasa, Pietro; Mondragón, Raúl J; Bianconi, Ginestra

    2014-01-01

    One of the most important challenges in network science is to quantify the information encoded in complex network structures. Disentangling randomness from organizational principles is even more demanding when networks have a multiplex nature. Multiplex networks are multilayer systems of [Formula: see text] nodes that can be linked in multiple interacting and co-evolving layers. In these networks, relevant information might not be captured if the single layers were analyzed separately. Here we demonstrate that such partial analysis of layers fails to capture significant correlations between weights and topology of complex multiplex networks. To this end, we study two weighted multiplex co-authorship and citation networks involving the authors included in the American Physical Society. We show that in these networks weights are strongly correlated with multiplex structure, and provide empirical evidence in favor of the advantage of studying weighted measures of multiplex networks, such as multistrength and the inverse multiparticipation ratio. Finally, we introduce a theoretical framework based on the entropy of multiplex ensembles to quantify the information stored in multiplex networks that would remain undetected if the single layers were analyzed in isolation.

  8. Serial Network Flow Monitor

    NASA Technical Reports Server (NTRS)

    Robinson, Julie A.; Tate-Brown, Judy M.

    2009-01-01

    Using a commercial software CD and minimal up-mass, SNFM monitors the Payload local area network (LAN) to analyze and troubleshoot LAN data traffic. Validating LAN traffic models may allow for faster and more reliable computer networks to sustain systems and science on future space missions. Research Summary: This experiment studies the function of the computer network onboard the ISS. On-orbit packet statistics are captured and used to validate ground based medium rate data link models and enhance the way that the local area network (LAN) is monitored. This information will allow monitoring and improvement in the data transfer capabilities of on-orbit computer networks. The Serial Network Flow Monitor (SNFM) experiment attempts to characterize the network equivalent of traffic jams on board ISS. The SNFM team is able to specifically target historical problem areas including the SAMS (Space Acceleration Measurement System) communication issues, data transmissions from the ISS to the ground teams, and multiple users on the network at the same time. By looking at how various users interact with each other on the network, conflicts can be identified and work can begin on solutions. SNFM is comprised of a commercial off the shelf software package that monitors packet traffic through the payload Ethernet LANs (local area networks) on board ISS.

  9. Collaborative learning in networks.

    PubMed

    Mason, Winter; Watts, Duncan J

    2012-01-17

    Complex problems in science, business, and engineering typically require some tradeoff between exploitation of known solutions and exploration for novel ones, where, in many cases, information about known solutions can also disseminate among individual problem solvers through formal or informal networks. Prior research on complex problem solving by collectives has found the counterintuitive result that inefficient networks, meaning networks that disseminate information relatively slowly, can perform better than efficient networks for problems that require extended exploration. In this paper, we report on a series of 256 Web-based experiments in which groups of 16 individuals collectively solved a complex problem and shared information through different communication networks. As expected, we found that collective exploration improved average success over independent exploration because good solutions could diffuse through the network. In contrast to prior work, however, we found that efficient networks outperformed inefficient networks, even in a problem space with qualitative properties thought to favor inefficient networks. We explain this result in terms of individual-level explore-exploit decisions, which we find were influenced by the network structure as well as by strategic considerations and the relative payoff between maxima. We conclude by discussing implications for real-world problem solving and possible extensions. PMID:22184216

  10. A network security monitor

    SciTech Connect

    Heberlein, L.T.; Dias, G.V.; Levitt, K.N.; Mukherjee, B.; Wood, J.; Wolber, D. . Dept. of Electrical Engineering and Computer Science)

    1989-11-01

    The study of security in computer networks is a rapidly growing area of interest because of the proliferation of networks and the paucity of security measures in most current networks. Since most networks consist of a collection of inter-connected local area networks (LANs), this paper concentrates on the security-related issues in a single broadcast LAN such as Ethernet. Specifically, we formalize various possible network attacks and outline methods of detecting them. Our basic strategy is to develop profiles of usage of network resources and then compare current usage patterns with the historical profile to determine possible security violations. Thus, our work is similar to the host-based intrusion-detection systems such as SRI's IDES. Different from such systems, however, is our use of a hierarchical model to refine the focus of the intrusion-detection mechanism. We also report on the development of our experimental LAN monitor currently under implementation. Several network attacks have been simulated and results on how the monitor has been able to detect these attacks are also analyzed. Initial results demonstrate that many network attacks are detectable with our monitor, although it can surely be defeated. Current work is focusing on the integration of network monitoring with host-based techniques. 20 refs., 2 figs.

  11. Cognitive Network Neuroscience

    PubMed Central

    Medaglia, John D.; Lynall, Mary-Ellen; Bassett, Danielle S.

    2016-01-01

    Network science provides theoretical, computational, and empirical tools that can be used to understand the structure and function of the human brain in novel ways using simple concepts and mathematical representations. Network neuroscience is a rapidly growing field that is providing considerable insight into human structural connectivity, functional connectivity while at rest, changes in functional networks over time (dynamics), and how these properties differ in clinical populations. In addition, a number of studies have begun to quantify network characteristics in a variety of cognitive processes and provide a context for understanding cognition from a network perspective. In this review, we outline the contributions of network science to cognitive neuroscience. We describe the methodology of network science as applied to the particular case of neuroimaging data and review its uses in investigating a range of cognitive functions including sensory processing, language, emotion, attention, cognitive control, learning, and memory. In conclusion, we discuss current frontiers and the specific challenges that must be overcome to integrate these complementary disciplines of network science and cognitive neuroscience. Increased communication between cognitive neuroscientists and network scientists could lead to significant discoveries under an emerging scientific intersection known as cognitive network neuroscience. PMID:25803596

  12. California Community College Education: Post Proposition 13.

    ERIC Educational Resources Information Center

    Howard, James E.

    A generic, descriptive system dynamics model is presented for a California community college district single campus. It provides an analytical tool for community college administrators who must consider the dynamic effects of policy changes on the system as a whole, rather than on isolated components of the system, when corrective financial…

  13. Twelve Propositions on Diversity in Higher Education

    ERIC Educational Resources Information Center

    Codling, Andrew; Meek, Lynn V.

    2006-01-01

    This paper explores the relationship between the diversity within a higher education system and five key factors, namely: the environment, policy intervention, funding, competition and co-operation, and ranking. The exploration is based on the extent to which higher education systems, particularly those of Australia and New Zealand, have…

  14. Is Being Popular a Risky Proposition?

    ERIC Educational Resources Information Center

    Mayeux, Lara; Sandstrom, Marlene J.; Cillessen, Antonius H. N.

    2008-01-01

    Longitudinal associations between social preference, perceived popularity, and risk behaviors (smoking, alcohol use, and sexual activity) were examined in a sample of high school students. Social preference did not predict any of the risk behaviors assessed, although the interaction between gender and social preference was predictive of sexual…

  15. The Value Proposition in Institutional Repositories

    ERIC Educational Resources Information Center

    Blythe, Erv; Chachra, Vinod

    2005-01-01

    In the education and research arena of the late 1970s and early 1980s, a struggle developed between those who advocated centralized, mainframe-based computing and those who advocated distributed computing. Ultimately, the debate reduced to whether economies of scale or economies of scope are more important to the effectiveness and efficiency of…

  16. Reasoning with Contrary-to-Fact Propositions.

    ERIC Educational Resources Information Center

    Markovits, Henry; Vachon, Robert

    1989-01-01

    Findings indicated that: (1) 10- and 13-year-olds had difficulty accepting contrary-to-fact premises as a basis for reasoning; (2) 15- and 18-year-olds found reasoning correctly more difficult with contrary-to-fact premises; and (3) among 5- and 7-year-olds, a fantasy context decreased the extent to which empirical knowledge interfered with…

  17. Control by quality: proposition of a typology.

    PubMed

    Pujo, P; Pillet, M

    The application of Quality tools and methods in industrial management has always had a fundamental impact on the control of production. It influences the behavior of the actors concerned, while introducing the necessary notions and formalizations, especially for production systems with little or no automation, which constitute a large part of the industrial activity. Several quality approaches are applied in the workshop and are implemented at the level of the control. In this paper, the authors present a typology of the various approaches that have successively influenced control, such as statistical process control, quality assurance, and continuous improvement. First the authors present a parallel between production control and quality organizational structure. They note the duality between control, which is aimed at increasing productivity, and quality, which aims to satisfy the needs of the customer. They also note the hierarchical organizational structure of these two systems of management with, at each level, the notion of a feedback loop. This notion is fundamental to any kind of decision making. The paper is organized around the operational, tactical, and strategic levels, by describing for each level the main methods and tools for control by quality. The overview of these tools and methods starts at the operational level, with the Statistical Process Control, the Taguchi technique, and the "six sigma" approach. On the tactical level, we find a quality system approach, with a documented description of the procedures introduced in the firm. The management system can refer here to Quality Assurance, Total Productive Maintenance, or Management by Total Quality. The formalization through procedures of the rules of decision governing the process control enhances the validity of these rules. This leads to the enhancement of their reliability and to their consolidation. All this counterbalances the human, intrinsically fluctuating, behavior of the control operators. Strategic control by quality is then detailed, and the two main approaches, the continuous improvement approach and the proactive improvement approach, are introduced. Finally, the authors observe that at each of the three levels, the continuous process improvement, which is a component of Total Quality, becomes an essential preoccupation for the control. Ultimately, the recursive utilization of the Deming cycle remains the best practice for the control by quality.

  18. The Ph.D. Value Proposition

    ERIC Educational Resources Information Center

    Cooper, Kenneth J.

    2012-01-01

    Atlanta University launched its doctor of arts in humanities (DAH) programs almost 40 years ago, and, since the 1988 merger with Clark College, Clark Atlanta University has continued to award the degrees. This fall, for the first time, its students will be able to earn Ph.D.s in humanities instead. In DAH programs around the country, there's been…

  19. Low-Cost, Robust, Threat-Aware Wireless Sensor Network for Assuring the Nation's Energy Infrastructure

    SciTech Connect

    Carols H. Rentel

    2007-03-31

    Eaton, in partnership with Oak Ridge National Laboratory and the Electric Power Research Institute (EPRI) has completed a project that applies a combination of wireless sensor network (WSN) technology, anticipatory theory, and a near-term value proposition based on diagnostics and process uptime to ensure the security and reliability of critical electrical power infrastructure. Representatives of several Eaton business units have been engaged to ensure a viable commercialization plan. Tennessee Valley Authority (TVA), American Electric Power (AEP), PEPCO, and Commonwealth Edison were recruited as partners to confirm and refine the requirements definition from the perspective of the utilities that actually operate the facilities to be protected. Those utilities have cooperated with on-site field tests as the project proceeds. Accomplishments of this project included: (1) the design, modeling, and simulation of the anticipatory wireless sensor network (A-WSN) that will be used to gather field information for the anticipatory application, (2) the design and implementation of hardware and software prototypes for laboratory and field experimentation, (3) stack and application integration, (4) develop installation and test plan, and (5) refinement of the commercialization plan.

  20. Exploiting Outage and Error Probability of Cooperative Incremental Relaying in Underwater Wireless Sensor Networks

    PubMed Central

    Nasir, Hina; Javaid, Nadeem; Sher, Muhammad; Qasim, Umar; Khan, Zahoor Ali; Alrajeh, Nabil; Niaz, Iftikhar Azim

    2016-01-01

    This paper embeds a bi-fold contribution for Underwater Wireless Sensor Networks (UWSNs); performance analysis of incremental relaying in terms of outage and error probability, and based on the analysis proposition of two new cooperative routing protocols. Subject to the first contribution, a three step procedure is carried out; a system model is presented, the number of available relays are determined, and based on cooperative incremental retransmission methodology, closed-form expressions for outage and error probability are derived. Subject to the second contribution, Adaptive Cooperation in Energy (ACE) efficient depth based routing and Enhanced-ACE (E-ACE) are presented. In the proposed model, feedback mechanism indicates success or failure of data transmission. If direct transmission is successful, there is no need for relaying by cooperative relay nodes. In case of failure, all the available relays retransmit the data one by one till the desired signal quality is achieved at destination. Simulation results show that the ACE and E-ACE significantly improves network performance, i.e., throughput, when compared with other incremental relaying protocols like Cooperative Automatic Repeat reQuest (CARQ). E-ACE and ACE achieve 69% and 63% more throughput respectively as compared to CARQ in hard underwater environment. PMID:27420061

  1. Exploiting Outage and Error Probability of Cooperative Incremental Relaying in Underwater Wireless Sensor Networks.

    PubMed

    Nasir, Hina; Javaid, Nadeem; Sher, Muhammad; Qasim, Umar; Khan, Zahoor Ali; Alrajeh, Nabil; Niaz, Iftikhar Azim

    2016-01-01

    This paper embeds a bi-fold contribution for Underwater Wireless Sensor Networks (UWSNs); performance analysis of incremental relaying in terms of outage and error probability, and based on the analysis proposition of two new cooperative routing protocols. Subject to the first contribution, a three step procedure is carried out; a system model is presented, the number of available relays are determined, and based on cooperative incremental retransmission methodology, closed-form expressions for outage and error probability are derived. Subject to the second contribution, Adaptive Cooperation in Energy (ACE) efficient depth based routing and Enhanced-ACE (E-ACE) are presented. In the proposed model, feedback mechanism indicates success or failure of data transmission. If direct transmission is successful, there is no need for relaying by cooperative relay nodes. In case of failure, all the available relays retransmit the data one by one till the desired signal quality is achieved at destination. Simulation results show that the ACE and E-ACE significantly improves network performance, i.e., throughput, when compared with other incremental relaying protocols like Cooperative Automatic Repeat reQuest (CARQ). E-ACE and ACE achieve 69% and 63% more throughput respectively as compared to CARQ in hard underwater environment. PMID:27420061

  2. MSAT network architecture

    NASA Technical Reports Server (NTRS)

    Davies, N. G.; Skerry, B.

    1990-01-01

    The Mobile Satellite (MSAT) communications system will support mobile voice and data services using circuit switched and packet switched facilities with interconnection to the public switched telephone network and private networks. Control of the satellite network will reside in a Network Control System (NCS) which is being designed to be extremely flexible to provide for the operation of the system initially with one multi-beam satellite, but with capability to add additional satellites which may have other beam configurations. The architecture of the NCS is described. The signalling system must be capable of supporting the protocols for the assignment of circuits for mobile public telephone and private network calls as well as identifying packet data networks. The structure of a straw-man signalling system is discussed.

  3. Visualizing Social Networks

    NASA Astrophysics Data System (ADS)

    Correa, Carlos D.; Ma, Kwan-Liu

    With today‘s ubiquity and popularity of social network applications, the ability to analyze and understand large networks in an efficient manner becomes critically important. However, as networks become larger and more complex, reasoning about social dynamics via simple statistics is not a feasible option. To overcome these limitations, we can rely on visual metaphors. Visualization nowadays is no longer a passive process that produces images from a set of numbers. Recent years have witnessed a convergence of social network analytics and visualization, coupled with interaction, that is changing the way analysts understand and characterize social networks. In this chapter, we discuss the main goal of visualization and how different metaphors are aimed towards elucidating different aspects of social networks, such as structure and semantics. We also describe a number of methods where analytics and visualization are interwoven towards providing a better comprehension of social structure and dynamics.

  4. Reconfigureable network node

    DOEpatents

    Vanderveen, Keith B.; Talbot, Edward B.; Mayer, Laurence E.

    2008-04-08

    Nodes in a network having a plurality of nodes establish communication links with other nodes using available transmission media, as the ability to establish such links becomes available and desirable. The nodes predict when existing communications links will fail, become overloaded or otherwise degrade network effectiveness and act to establish substitute or additional links before the node's ability to communicate with the other nodes on the network is adversely affected. A node stores network topology information and programmed link establishment rules and criteria. The node evaluates characteristics that predict existing links with other nodes becoming unavailable or degraded. The node then determines whether it can form a communication link with a substitute node, in order to maintain connectivity with the network. When changing its communication links, a node broadcasts that information to the network. Other nodes update their stored topology information and consider the updated topology when establishing new communications links for themselves.

  5. Seven Deadliest Network Attacks

    SciTech Connect

    Prowell, Stacy J; Borkin, Michael; Kraus, Robert

    2010-05-01

    Do you need to keep up with the latest hacks, attacks, and exploits effecting networks? Then you need "Seven Deadliest Network Attacks". This book pinpoints the most dangerous hacks and exploits specific to networks, laying out the anatomy of these attacks including how to make your system more secure. You will discover the best ways to defend against these vicious hacks with step-by-step instruction and learn techniques to make your computer and network impenetrable. Attacks detailed in this book include: Denial of Service; War Dialing; Penetration 'Testing'; Protocol Tunneling; Spanning Tree Attacks; Man-in-the-Middle; and, Password Replay. Knowledge is power, find out about the most dominant attacks currently waging war on computers and networks globally. Discover the best ways to defend against these vicious attacks; step-by-step instruction shows you how. Institute countermeasures, don't be caught defenseless again, learn techniques to make your computer and network impenetrable.

  6. Computer networking at FERMILAB

    SciTech Connect

    Chartrand, G.

    1986-05-01

    Management aspects of data communications facilities at Fermilab are described. Local area networks include Ferminet, a broadband CATV system which serves as a backbone-type carrier for high-speed data traffic between major network nodes; micom network, four Micom Micro-600/2A port selectors via private twisted pair cables, dedicated telephone circuits, or Micom 800/2 statistical multiplexors; and Decnet/Ethernet, several small local area networks which provide host-to-host communications for about 35 VAX computers systems. Wide area (off site) computer networking includes an off site Micom network which provides access to all of Fermilab's computer systems for 10 universities via leased lines or modem; Tymnet, used by many European and Japanese collaborations: Physnet, used for shared data processing task communications by large collaborations of universities; Bitnet, used for file transfer, electronic mail, and communications with CERN; and Mfenet, for access to supercomputers. Plans to participate in Hepnet are also addressed. 3 figs. (DWL)

  7. NASA Communications Augmentation network

    NASA Astrophysics Data System (ADS)

    Omidyar, Guy C.; Butler, Thomas E.; Laios, Straton C.

    1990-09-01

    The NASA Communications (Nascom) Division of the Mission Operations and Data Systems Directorate (MO&DSD) is to undertake a major initiative to develop the Nascom Augmentation (NAUG) network to achieve its long-range service objectives for operational data transport to support the Space Station Freedom Program, the Earth Observing System (EOS), and other projects. The NAUG is the Nascom ground communications network being developed to accommodate the operational traffic of the mid-1990s and beyond. The NAUG network development will be based on the Open Systems Interconnection Reference Model (OSI-RM). This paper describes the NAUG network architecture, subsystems, topology, and services; addresses issues of internetworking the Nascom network with other elements of the Space Station Information System (SSIS); discusses the operations environment. This paper also notes the areas of related research and presents the current conception of how the network will provide broadband services in 1998.

  8. Compressive Network Analysis

    PubMed Central

    Jiang, Xiaoye; Yao, Yuan; Liu, Han; Guibas, Leonidas

    2014-01-01

    Modern data acquisition routinely produces massive amounts of network data. Though many methods and models have been proposed to analyze such data, the research of network data is largely disconnected with the classical theory of statistical learning and signal processing. In this paper, we present a new framework for modeling network data, which connects two seemingly different areas: network data analysis and compressed sensing. From a nonparametric perspective, we model an observed network using a large dictionary. In particular, we consider the network clique detection problem and show connections between our formulation with a new algebraic tool, namely Randon basis pursuit in homogeneous spaces. Such a connection allows us to identify rigorous recovery conditions for clique detection problems. Though this paper is mainly conceptual, we also develop practical approximation algorithms for solving empirical problems and demonstrate their usefulness on real-world datasets. PMID:25620806

  9. Professional social networking.

    PubMed

    Rowley, Robert D

    2014-12-01

    We review the current state of social communication between healthcare professionals, the role of consumer social networking, and some emerging technologies to address the gaps. In particular, the review covers (1) the current state of loose social networking for continuing medical education (CME) and other broadcast information dissemination; (2) social networking for business promotion; (3) social networking for peer collaboration, including simple communication as well as more robust data-centered collaboration around patient care; and (4) engaging patients on social platforms, including integrating consumer-originated data into the mix of healthcare data. We will see how, as the nature of healthcare delivery moves from the institution-centric way of tradition to a more social and networked ambulatory pattern that we see emerging today, the nature of health IT has also moved from enterprise-centric systems to more socially networked, cloud-based options.

  10. Professional social networking.

    PubMed

    Rowley, Robert D

    2014-12-01

    We review the current state of social communication between healthcare professionals, the role of consumer social networking, and some emerging technologies to address the gaps. In particular, the review covers (1) the current state of loose social networking for continuing medical education (CME) and other broadcast information dissemination; (2) social networking for business promotion; (3) social networking for peer collaboration, including simple communication as well as more robust data-centered collaboration around patient care; and (4) engaging patients on social platforms, including integrating consumer-originated data into the mix of healthcare data. We will see how, as the nature of healthcare delivery moves from the institution-centric way of tradition to a more social and networked ambulatory pattern that we see emerging today, the nature of health IT has also moved from enterprise-centric systems to more socially networked, cloud-based options. PMID:25308391

  11. National Highway Planning Network

    1992-02-02

    NHPN, the National Highway Planning Network, is a database of major highways in the continental United States that is used for national-level analyses of highway transportation issues that require use of a network, such as studies of highway performance, network design, social and environmental impacts of transportation, vehicle routing and scheduling, and mapping. The network is based on a set of roadways digitized by the U. S. Geological Survey (USGS) from the 1980 National Atlasmore » and has been enhanced with additional roads, attribute detail, and topological error corrections to produce a true analytic network. All data have been derived from or checked against information obtained from state and Federal governmental agencies. Two files comprise this network: one describing links and the other nodes. This release, NHPN1.0, contains 44,960 links and 28,512 nodes representing approximately 380,000 miles of roadway.« less

  12. Mutually connected component of networks of networks with replica nodes

    NASA Astrophysics Data System (ADS)

    Bianconi, Ginestra; Dorogovtsev, Sergey N.; Mendes, José F. F.

    2015-01-01

    We describe the emergence of the giant mutually connected component in networks of networks in which each node has a single replica node in any layer and can be interdependent only on its replica nodes in the interdependent layers. We prove that if, in these networks, all the nodes of one network (layer) are interdependent on the nodes of the same other interconnected layer, then, remarkably, the mutually connected component does not depend on the topology of the network of networks. This component coincides with the mutual component of the fully connected network of networks constructed from the same set of layers, i.e., a multiplex network.

  13. The Unesco/UIE Literacy Network: A Network of Networks.

    ERIC Educational Resources Information Center

    Giere, Ursula

    In order to achieve significant results, crucial criteria for stabilizing a network's capacity for dialog are high levels of commitment to offer high quality knowledge, two-way translation from research knowledge to practitioners and from practice to researchers, a maximum size, face-to-face communication, infrastructure, and funds for…

  14. The Deep Space Network

    NASA Technical Reports Server (NTRS)

    1974-01-01

    The objectives, functions, and organization, of the Deep Space Network are summarized. Deep Space stations, ground communications, and network operations control capabilities are described. The network is designed for two-way communications with unmanned spacecraft traveling approximately 1600 km from earth to the farthest planets in the solar system. It has provided tracking and data acquisition support for the following projects: Ranger, Surveyor, Mariner, Pioneer, Apollo, Helios, Viking, and the Lunar Orbiter.

  15. NASA Integrated Network COOP

    NASA Technical Reports Server (NTRS)

    Anderson, Michael L.; Wright, Nathaniel; Tai, Wallace

    2012-01-01

    Natural disasters, terrorist attacks, civil unrest, and other events have the potential of disrupting mission-essential operations in any space communications network. NASA's Space Communications and Navigation office (SCaN) is in the process of studying options for integrating the three existing NASA network elements, the Deep Space Network, the Near Earth Network, and the Space Network, into a single integrated network with common services and interfaces. The need to maintain Continuity of Operations (COOP) after a disastrous event has a direct impact on the future network design and operations concepts. The SCaN Integrated Network will provide support to a variety of user missions. The missions have diverse requirements and include anything from earth based platforms to planetary missions and rovers. It is presumed that an integrated network, with common interfaces and processes, provides an inherent advantage to COOP in that multiple elements and networks can provide cross-support in a seamless manner. The results of trade studies support this assumption but also show that centralization as a means of achieving integration can result in single points of failure that must be mitigated. The cost to provide this mitigation can be substantial. In support of this effort, the team evaluated the current approaches to COOP, developed multiple potential approaches to COOP in a future integrated network, evaluated the interdependencies of the various approaches to the various network control and operations options, and did a best value assessment of the options. The paper will describe the trade space, the study methods, and results of the study.

  16. Albuquerque Basin seismic network

    USGS Publications Warehouse

    Jaksha, Lawrence H.; Locke, Jerry; Thompson, J.B.; Garcia, Alvin

    1977-01-01

    The U.S. Geological Survey has recently completed the installation of a seismic network around the Albuquerque Basin in New Mexico. The network consists of two seismometer arrays, a thirteen-station array monitoring an area of approximately 28,000 km 2 and an eight-element array monitoring the area immediately adjacent to the Albuquerque Seismological Laboratory. This report describes the instrumentation deployed in the network.

  17. Affinity driven social networks

    NASA Astrophysics Data System (ADS)

    Ruyú, B.; Kuperman, M. N.

    2007-04-01

    In this work we present a model for evolving networks, where the driven force is related to the social affinity between individuals of a population. In the model, a set of individuals initially arranged on a regular ordered network and thus linked with their closest neighbors are allowed to rearrange their connections according to a dynamics closely related to that of the stable marriage problem. We show that the behavior of some topological properties of the resulting networks follows a non trivial pattern.

  18. The deep space network

    NASA Technical Reports Server (NTRS)

    1975-01-01

    The objectives, functions, and organization of the Deep Space Network are summarized along with deep space station, ground communication, and network operations control capabilities. Mission support of ongoing planetary/interplanetary flight projects is discussed with emphasis on Viking orbiter radio frequency compatibility tests, the Pioneer Venus orbiter mission, and Helios-1 mission status and operations. Progress is also reported in tracking and data acquisition research and technology, network engineering, hardware and software implementation, and operations.

  19. Exploring neural network technology

    SciTech Connect

    Naser, J.; Maulbetsch, J.

    1992-12-01

    EPRI is funding several projects to explore neural network technology, a form of artificial intelligence that some believe may mimic the way the human brain processes information. This research seeks to provide a better understanding of fundamental neural network characteristics and to identify promising utility industry applications. Results to date indicate that the unique attributes of neural networks could lead to improved monitoring, diagnostic, and control capabilities for a variety of complex utility operations. 2 figs.

  20. Network problem threshold

    NASA Technical Reports Server (NTRS)

    Gejji, Raghvendra, R.

    1992-01-01

    Network transmission errors such as collisions, CRC errors, misalignment, etc. are statistical in nature. Although errors can vary randomly, a high level of errors does indicate specific network problems, e.g. equipment failure. In this project, we have studied the random nature of collisions theoretically as well as by gathering statistics, and established a numerical threshold above which a network problem is indicated with high probability.

  1. Network of Networks and the Climate System

    NASA Astrophysics Data System (ADS)

    Kurths, Jürgen; Boers, Niklas; Bookhagen, Bodo; Donges, Jonathan; Donner, Reik; Malik, Nishant; Marwan, Norbert; Stolbova, Veronika

    2013-04-01

    Network of networks is a new direction in complex systems science. One can find such networks in various fields, such as infrastructure (power grids etc.), human brain or Earth system. Basic properties and new characteristics, such as cross-degree, or cross-betweenness will be discussed. This allows us to quantify the structural role of single vertices or whole sub-networks with respect to the interaction of a pair of subnetworks on local, mesoscopic, and global topological scales. Next, we consider an inverse problem: Is there a backbone-like structure underlying the climate system? For this we propose a method to reconstruct and analyze a complex network from data generated by a spatio-temporal dynamical system. This technique is then applied to 3-dimensional data of the climate system. We interpret different heights in the atmosphere as different networks and the whole as a network of networks. This approach enables us to uncover relations to global circulation patterns in oceans and atmosphere. The global scale view on climate networks offers promising new perspectives for detecting dynamical structures based on nonlinear physical processes in the climate system. This concept is applied to Indian Monsoon data in order to characterize the regional occurrence of strong rain events and its impact on predictability. References: Arenas, A., A. Diaz-Guilera, J. Kurths, Y. Moreno, and C. Zhou, Phys. Reports 2008, 469, 93. Donges, J., Y. Zou, N. Marwan, and J. Kurths, Europhys. Lett. 2009, 87, 48007. Donner, R., Y. Zou, J. Donges, N. Marwan, and J. Kurths, Phys. Rev. E 2010, 81, 015101(R ). Mokhov, I. I., D. A. Smirnov, P. I. Nakonechny, S. S. Kozlenko, E. P. Seleznev, and J. Kurths, Geophys. Res. Lett. 2011, 38, L00F04. Malik, N., B. Bookhagen, N. Marwan, and J. Kurths, Climate Dynamics, 2012, 39, 971. Donges, J., H. Schultz, N. Marwan, Y. Zou, J. Kurths, Eur. J. Phys. B 2011, 84, 635-651. Donges, J., R. Donner, M. Trauth, N. Marwan, H.J. Schellnhuber, and J. Kurths

  2. Network discovery with DCM

    PubMed Central

    Friston, Karl J.; Li, Baojuan; Daunizeau, Jean; Stephan, Klaas E.

    2011-01-01

    This paper is about inferring or discovering the functional architecture of distributed systems using Dynamic Causal Modelling (DCM). We describe a scheme that recovers the (dynamic) Bayesian dependency graph (connections in a network) using observed network activity. This network discovery uses Bayesian model selection to identify the sparsity structure (absence of edges or connections) in a graph that best explains observed time-series. The implicit adjacency matrix specifies the form of the network (e.g., cyclic or acyclic) and its graph-theoretical attributes (e.g., degree distribution). The scheme is illustrated using functional magnetic resonance imaging (fMRI) time series to discover functional brain networks. Crucially, it can be applied to experimentally evoked responses (activation studies) or endogenous activity in task-free (resting state) fMRI studies. Unlike conventional approaches to network discovery, DCM permits the analysis of directed and cyclic graphs. Furthermore, it eschews (implausible) Markovian assumptions about the serial independence of random fluctuations. The scheme furnishes a network description of distributed activity in the brain that is optimal in the sense of having the greatest conditional probability, relative to other networks. The networks are characterised in terms of their connectivity or adjacency matrices and conditional distributions over the directed (and reciprocal) effective connectivity between connected nodes or regions. We envisage that this approach will provide a useful complement to current analyses of functional connectivity for both activation and resting-state studies. PMID:21182971

  3. Exploring complex networks

    NASA Astrophysics Data System (ADS)

    Strogatz, Steven H.

    2001-03-01

    The study of networks pervades all of science, from neurobiology to statistical physics. The most basic issues are structural: how does one characterize the wiring diagram of a food web or the Internet or the metabolic network of the bacterium Escherichia coli? Are there any unifying principles underlying their topology? From the perspective of nonlinear dynamics, we would also like to understand how an enormous network of interacting dynamical systems - be they neurons, power stations or lasers - will behave collectively, given their individual dynamics and coupling architecture. Researchers are only now beginning to unravel the structure and dynamics of complex networks.

  4. Heterogeneous broadband network

    NASA Astrophysics Data System (ADS)

    Dittmann, Lars

    1995-11-01

    Although the vision for the future Integrated Broadband Communication Network (IBCN) is an all optical network, it is certain that for a long period to come, the network will remain very heterogeneous, with a mixture of different physical media (fiber, coax and twisted pair), transmission systems (PDH, SDH, ADSL) and transport protocols (TCP/IP, AAL/ATM, frame relay). In the current work towards the IBCN, the ATM concept is considered the generic network protocol for both public and private network, with the ability to use different underlying transmission protocols and, through adaptation protocols, provide the appropriate services (old as well as new) to the customer. One of the major difficulties of heterogeneous network is the restriction that is usually given by the lowest common denominator, e.g. in terms of single channel capacity. A possible way to overcome these limitations is by extending the ATM concept with a multilink capability, that allows us to use separate resources as one common. The improved flexibility obtained by this protocol extension further allows a real time optimization of network and call configuration, without any impact on the quality of service seen from the user. This paper describes an example of an ATM based multilink protocol that has been experimentally implemented within the RACE project 'STRATOSPHERIC'. The paper outlines the complexity of introducing an extra network functionality compared with the added value, such as an improved ability to recover an error due to a malfunctioning network component.

  5. Mobile Virtual Private Networking

    NASA Astrophysics Data System (ADS)

    Pulkkis, Göran; Grahn, Kaj; Mårtens, Mathias; Mattsson, Jonny

    Mobile Virtual Private Networking (VPN) solutions based on the Internet Security Protocol (IPSec), Transport Layer Security/Secure Socket Layer (SSL/TLS), Secure Shell (SSH), 3G/GPRS cellular networks, Mobile IP, and the presently experimental Host Identity Protocol (HIP) are described, compared and evaluated. Mobile VPN solutions based on HIP are recommended for future networking because of superior processing efficiency and network capacity demand features. Mobile VPN implementation issues associated with the IP protocol versions IPv4 and IPv6 are also evaluated. Mobile VPN implementation experiences are presented and discussed.

  6. Future Optical Networks

    NASA Astrophysics Data System (ADS)

    O'Mahony, Michael J.; Politi, Christina; Klonidis, Dimitrios; Nejabati, Reza; Simeonidou, Dimitra

    2006-12-01

    This paper presents views on the future of optical networking. A historical look at the emergence of optical networking is first taken, followed by a discussion on the drivers pushing for a new and pervasive network, which is based on photonics and can satisfy the needs of a broadening base of residential, business, and scientific users. Regional plans and targets for optical networking are reviewed to understand which current approaches are judged important. Today, two thrusts are driving separate optical network infrastructure models, namely 1) the need by nations to provide a ubiquitous network infrastructure to support all the future services and telecommunication needs of residential and business users and 2) increasing demands by the scientific community for networks to support their requirements with respect to large-scale data transport and processing. This paper discusses these network models together with the key enabling technologies currently being considered for future implementation, including optical circuit, burst and packet switching, and optical code-division multiplexing. Critical subsystem functionalities are also reviewed. The discussion considers how these separate models might eventually merge to form a global optical network infrastructure.

  7. Composite Random Fiber Networks

    NASA Astrophysics Data System (ADS)

    Picu, Catalin; Shahsavari, Ali

    2013-03-01

    Systems made from fibers are common in the biological and engineering worlds. In many instances, as for example in skin, where elastin and collagen fibers are present, the fiber network is composite, in the sense that it contains fibers of very different properties. The relationship between microstructural parameters and the elastic moduli of random fiber networks containing a single type of fiber is understood. In this work we address a similar target for the composite networks. We show that linear superposition of the contributions to stiffness of individual sub-networks does not apply and interesting non-linear effects are observed. A physical basis of these effects is proposed.

  8. Celestial data routing network

    NASA Astrophysics Data System (ADS)

    Bordetsky, Alex

    2000-11-01

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

  9. Mission Critical Networking

    SciTech Connect

    Eltoweissy, Mohamed Y.; Du, David H.C.; Gerla, Mario; Giordano, Silvia; Gouda, Mohamed; Schulzrinne, Henning; Youssef, Moustafa

    2010-06-01

    Mission-Critical Networking (MCN) refers to networking for application domains where life or livelihood may be at risk. Typical application domains for MCN include critical infrastructure protection and operation, emergency and crisis intervention, healthcare services, and military operations. Such networking is essential for safety, security and economic vitality in our complex world characterized by uncertainty, heterogeneity, emergent behaviors, and the need for reliable and timely response. MCN comprise networking technology, infrastructures and services that may alleviate the risk and directly enable and enhance connectivity for mission-critical information exchange among diverse, widely dispersed, mobile users.

  10. Generalized Communities in Networks

    NASA Astrophysics Data System (ADS)

    Newman, M. E. J.; Peixoto, Tiago P.

    2015-08-01

    A substantial volume of research is devoted to studies of community structure in networks, but communities are not the only possible form of large-scale network structure. Here, we describe a broad extension of community structure that encompasses traditional communities but includes a wide range of generalized structural patterns as well. We describe a principled method for detecting this generalized structure in empirical network data and demonstrate with real-world examples how it can be used to learn new things about the shape and meaning of networks.

  11. Mercury in estuarine sediments of the Manguaba and Botafogo River : A background and baseline values proposition in comparison to relatively well preserved and polluted aquatic systems under tropical countries

    NASA Astrophysics Data System (ADS)

    Lima, Marta

    2013-04-01

    Mercury in estuarine sediments of the Manguaba and Botafogo River : A background and baseline values proposition in comparison to relatively well preserved and polluted aquatic systems under tropical countries Lima, Marta1; Menor, Eldemar2; Lima, Enjolras3; Neumann, Virginio4 1MFGTransportes, Brazil; 2Federal University of Pernambuco, Brazil 3Servico Geologico do Brasil-CPRM, Brazil 4Federal University of Pernambuco, Brazil Heavy metal (HM) concentrations in estuarine sediments of the Botafogo and Manguaba river, North-eastern Brazil were investigated on basis of samples from a bottom core drill performed 4km from the mouth of the rivers. Total sediments (TS) of the sliced profiles (62 cm, Botafogo river and 87 cm, Manguaba river ) were submitted to chemical analysis (51 elements), mineralogical analysis (XRD) and statistical study, followed by stoichiometric calculations. Geochronologic determinations of 210Pb allowed studying the evolution of the contamination level approximately 150 year-old interval in the Botafogo river. Mercury (Hg) and Arsenic (As) are emphasized because of a chlorine-soda industry that dumps its effluents about 15 km upstream of the estuary and extensive cultivation of sugarcane existent in this watershed. Hg background in pelitic total sediments (PTS) was certain established considering the Hg content (126 ppb) in sedimentary intervals previous to 1910. The production of chlorine-soda (since 1963) coincides with a drastic increase of the Hg concentrations and contemporary values around 6.000 ppb, without interruption in the pollutant process. The conclusions found that the Hg was the main indicator of anthropogenic contribution in the sediments of the Botafogo river. On the other hand, an increase in the Hg-As concentrations has been observed at the last decades due to an increase of the clay mineral fraction in TS of the Manguaga river. This scenario indicates that the accumulation of HM has been constant since the last decades, under a

  12. Entangled networks, synchronization, and optimal network topology.

    PubMed

    Donetti, Luca; Hurtado, Pablo I; Muñoz, Miguel A

    2005-10-28

    A new family of graphs, entangled networks, with optimal properties in many respects, is introduced. By definition, their topology is such that it optimizes synchronizability for many dynamical processes. These networks are shown to have an extremely homogeneous structure: degree, node distance, betweenness, and loop distributions are all very narrow. Also, they are characterized by a very interwoven (entangled) structure with short average distances, large loops, and no well-defined community structure. This family of nets exhibits an excellent performance with respect to other flow properties such as robustness against errors and attacks, minimal first-passage time of random walks, efficient communication, etc. These remarkable features convert entangled networks in a useful concept, optimal or almost optimal in many senses, and with plenty of potential applications in computer science or neuroscience.

  13. Reverse logistics network for municipal solid waste management: The inclusion of waste pickers as a Brazilian legal requirement.

    PubMed

    Ferri, Giovane Lopes; Chaves, Gisele de Lorena Diniz; Ribeiro, Glaydston Mattos

    2015-06-01

    This study proposes a reverse logistics network involved in the management of municipal solid waste (MSW) to solve the challenge of economically managing these wastes considering the recent legal requirements of the Brazilian Waste Management Policy. The feasibility of the allocation of MSW material recovery facilities (MRF) as intermediate points between the generators of these wastes and the options for reuse and disposal was evaluated, as well as the participation of associations and cooperatives of waste pickers. This network was mathematically modelled and validated through a scenario analysis of the municipality of São Mateus, which makes the location model more complete and applicable in practice. The mathematical model allows the determination of the number of facilities required for the reverse logistics network, their location, capacities, and product flows between these facilities. The fixed costs of installation and operation of the proposed MRF were balanced with the reduction of transport costs, allowing the inclusion of waste pickers to the reverse logistics network. The main contribution of this study lies in the proposition of a reverse logistics network for MSW simultaneously involving legal, environmental, economic and social criteria, which is a very complex goal. This study can guide practices in other countries that have realities similar to those in Brazil of accelerated urbanisation without adequate planning for solid waste management, added to the strong presence of waste pickers that, through the characteristic of social vulnerability, must be included in the system. In addition to the theoretical contribution to the reverse logistics network problem, this study aids in decision-making for public managers who have limited technical and administrative capacities for the management of solid wastes. PMID:25840735

  14. Reverse logistics network for municipal solid waste management: The inclusion of waste pickers as a Brazilian legal requirement.

    PubMed

    Ferri, Giovane Lopes; Chaves, Gisele de Lorena Diniz; Ribeiro, Glaydston Mattos

    2015-06-01

    This study proposes a reverse logistics network involved in the management of municipal solid waste (MSW) to solve the challenge of economically managing these wastes considering the recent legal requirements of the Brazilian Waste Management Policy. The feasibility of the allocation of MSW material recovery facilities (MRF) as intermediate points between the generators of these wastes and the options for reuse and disposal was evaluated, as well as the participation of associations and cooperatives of waste pickers. This network was mathematically modelled and validated through a scenario analysis of the municipality of São Mateus, which makes the location model more complete and applicable in practice. The mathematical model allows the determination of the number of facilities required for the reverse logistics network, their location, capacities, and product flows between these facilities. The fixed costs of installation and operation of the proposed MRF were balanced with the reduction of transport costs, allowing the inclusion of waste pickers to the reverse logistics network. The main contribution of this study lies in the proposition of a reverse logistics network for MSW simultaneously involving legal, environmental, economic and social criteria, which is a very complex goal. This study can guide practices in other countries that have realities similar to those in Brazil of accelerated urbanisation without adequate planning for solid waste management, added to the strong presence of waste pickers that, through the characteristic of social vulnerability, must be included in the system. In addition to the theoretical contribution to the reverse logistics network problem, this study aids in decision-making for public managers who have limited technical and administrative capacities for the management of solid wastes.

  15. Better sales networks.

    PubMed

    Ustüner, Tuba; Godes, David

    2006-01-01

    Anyone in sales will tell you that social networks are critical. The more contacts you have, the more leads you'll generate, and, ultimately, the more sales you'll make. But that's a vast oversimplification. Different configurations of networks produce different results, and the salesperson who develops a nuanced understanding of social networks will outshine competitors. The salesperson's job changes over the course of the selling process. Different abilities are required in each stage of the sale: identifying prospects, gaining buy-in from potential customers, creating solutions, and closing the deal. Success in the first stage, for instance, depends on the salesperson acquiring precise and timely information about opportunities from contacts in the marketplace. Closing the deal requires the salesperson to mobilize contacts from prior sales to act as references. Managers often view sales networks only in terms of direct contacts. But someone who knows lots of people doesn't necessarily have an effective network because networks often pay off most handsomely through indirect contacts. Moreover, the density of the connections in a network is important. Do a salesperson's contacts know all the same people, or are their associates widely dispersed? Sparse networks are better, for example, at generating unique information. Managers can use three levers--sales force structure, compensation, and skills development--to encourage salespeople to adopt a network-based view and make the best possible use of social webs. For example, the sales force can be restructured to decouple lead generation from other tasks because some people are very good at building diverse ties but not so good at maintaining other kinds of networks. Companies that take steps of this kind to help their sales teams build better networks will reap tremendous advantages.

  16. Better sales networks.

    PubMed

    Ustüner, Tuba; Godes, David

    2006-01-01

    Anyone in sales will tell you that social networks are critical. The more contacts you have, the more leads you'll generate, and, ultimately, the more sales you'll make. But that's a vast oversimplification. Different configurations of networks produce different results, and the salesperson who develops a nuanced understanding of social networks will outshine competitors. The salesperson's job changes over the course of the selling process. Different abilities are required in each stage of the sale: identifying prospects, gaining buy-in from potential customers, creating solutions, and closing the deal. Success in the first stage, for instance, depends on the salesperson acquiring precise and timely information about opportunities from contacts in the marketplace. Closing the deal requires the salesperson to mobilize contacts from prior sales to act as references. Managers often view sales networks only in terms of direct contacts. But someone who knows lots of people doesn't necessarily have an effective network because networks often pay off most handsomely through indirect contacts. Moreover, the density of the connections in a network is important. Do a salesperson's contacts know all the same people, or are their associates widely dispersed? Sparse networks are better, for example, at generating unique information. Managers can use three levers--sales force structure, compensation, and skills development--to encourage salespeople to adopt a network-based view and make the best possible use of social webs. For example, the sales force can be restructured to decouple lead generation from other tasks because some people are very good at building diverse ties but not so good at maintaining other kinds of networks. Companies that take steps of this kind to help their sales teams build better networks will reap tremendous advantages. PMID:16846193

  17. The Benefits of Grid Networks

    ERIC Educational Resources Information Center

    Tennant, Roy

    2005-01-01

    In the article, the author talks about the benefits of grid networks. In speaking of grid networks the author is referring to both networks of computers and networks of humans connected together in a grid topology. Examples are provided of how grid networks are beneficial today and the ways in which they have been used.

  18. Gateways among Academic Computer Networks.

    ERIC Educational Resources Information Center

    McCredie, John W.

    National intercampus computer networks are discussed, along with six illustrative networks. Attention is focused on computer networks with significant academic usage through which special software is available to manage resources in the network. It is noted that computer networks have widespread use among academics for communication in the form of…

  19. Internationalisation Network: A Finnish Experience

    ERIC Educational Resources Information Center

    Kantola, Mauri; Hautala, Jouni

    2008-01-01

    One of the main issues of internationalisation is networking. The network way of action within higher education institutions (HEIs) represents new modes of the information work. Networks are worth evaluating more precisely in the future, and social network analysis (SNA) is a useful tool for this evaluation. This article describes the network of…

  20. Chaotic Neural Networks and Beyond

    NASA Astrophysics Data System (ADS)

    Aihara, Kazuyuki; Yamada, Taiji; Oku, Makito

    2013-01-01

    A chaotic neuron model which is closely related to deterministic chaos observed experimentally with squid giant axons is explained, and used to construct a chaotic neural network model. Further, such a chaotic neural network is extended to different chaotic models such as a largescale memory relation network, a locally connected network, a vector-valued network, and a quaternionic-valued neuron.

  1. Local Area Networks: Part II.

    ERIC Educational Resources Information Center

    Dessy, Raymond E., Ed.

    1982-01-01

    Discusses five approaches used by industry/colleges to provide local area network (LAN) capabilities in the analytical laboratory: (1) mixed baseband bus network coupled to a star net; (2) broadband bus network; (3) ring network; (4) star network coupled to broadband net; and (5) simple multiprocessor center. Part I (September issue) focused on…

  2. Cascading Failures and Recovery in Networks of Networks

    NASA Astrophysics Data System (ADS)

    Havlin, Shlomo

    Network science have been focused on the properties of a single isolated network that does not interact or depends on other networks. In reality, many real-networks, such as power grids, transportation and communication infrastructures interact and depend on other networks. I will present a framework for studying the vulnerability and the recovery of networks of interdependent networks. In interdependent networks, when nodes in one network fail, they cause dependent nodes in other networks to also fail. This is also the case when some nodes like certain locations play a role in two networks -multiplex. This may happen recursively and can lead to a cascade of failures and to a sudden fragmentation of the system. I will present analytical solutions for the critical threshold and the giant component of a network of n interdependent networks. I will show, that the general theory has many novel features that are not present in the classical network theory. When recovery of components is possible global spontaneous recovery of the networks and hysteresis phenomena occur and the theory suggests an optimal repairing strategy of system of systems. I will also show that interdependent networks embedded in space are significantly more vulnerable compared to non embedded networks. In particular, small localized attacks may lead to cascading failures and catastrophic consequences.Thus, analyzing data of real network of networks is highly required to understand the system vulnerability. DTRA, ONR, Israel Science Foundation.

  3. An approach for modeling vulnerability of the network of networks

    NASA Astrophysics Data System (ADS)

    Zhang, Jianhua; Song, Bo; Zhang, Zhaojun; Liu, Haikuan

    2014-10-01

    In this paper, a framework is given to model the network of networks and to investigate the vulnerability of the network of networks subjected to failures. Because there are several redundant systems in infrastructure systems, the dependent intensity between two networks is introduced and adopted to discuss the vulnerability of the interdependent infrastructure networks subjected to failures. Shanghai electrified rail transit network is used to illustrate the feasibility and effectiveness of the proposed framework. Because the rail network is dependent on the power grid and communication network, the corresponding power grid and communication network are also included in this system. Meanwhile the failures to the power grid and communication network are utilized to investigate the vulnerability of the rail network. The results show that the rail network strongly depends on the power grid and weakly depends on the communication network, and the transport functionality loss of the rail network increases with the increase of dependent intensity. Meanwhile the highest betweenness node-based attack to the power grid and the largest degree node-based attack to the communication network can result in the most functionality losses to the rail network. Moreover, the functionality loss of the rail network has the smallest value when the tolerance parameter of the power grid equals 0.75 and the critical nodes of the power grid and communication network can be obtained by simulations.

  4. FTS2000 network architecture

    NASA Technical Reports Server (NTRS)

    Klenart, John

    1991-01-01

    The network architecture of FTS2000 is graphically depicted. A map of network A topology is provided, with interservice nodes. Next, the four basic element of the architecture is laid out. Then, the FTS2000 time line is reproduced. A list of equipment supporting FTS2000 dedicated transmissions is given. Finally, access alternatives are shown.

  5. Information Networks in Biomedicine

    ERIC Educational Resources Information Center

    Millard, William L.

    1975-01-01

    Describes current biomedical information networks, focusing on those with an educational function, and elaborates on the problems encountered in planning, implementing, utilizing and evaluating such networks. Journal of Biocommunication, T. Banks, Educ. TV-431N, U. of Calif., San Francisco 94143. Subscription Rates: individuals and libraries,…

  6. The protein folding network

    NASA Astrophysics Data System (ADS)

    Rao, Francesco; Caflisch, Amedeo

    2004-03-01

    Networks are everywhere. The conformation space of a 20-residue antiparallel beta-sheet peptide [1], sampled by molecular dynamics simulations, is mapped to a network. Conformations are nodes of the network, and the transitions between them are links. As previously found for the World-Wide Web as well as for social and biological networks , the conformation space contains highly connected hubs like the native state which is the most populated free energy basin. Furthermore, the network shows a hierarchical modularity [2] which is consistent with the funnel mechanism of folding [3] and is not observed for a random heteropolymer lacking a native state. Here we show that the conformation space network describes the free energy landscape without requiring projections into arbitrarily chosen reaction coordinates. The network analysis provides a basis for understanding the heterogeneity of the folding transition state and the existence of multiple pathways. [1] P. Ferrara and A. Caflisch, Folding simulations of a three-stranded antiparallel beta-sheet peptide, PNAS 97, 10780-10785 (2000). [2] Ravasz, E. and Barabási, A. L. Hierarchical organization in complex networks. Phys. Rev. E 67, 026112 (2003). [3] Dill, K. and Chan, H From Levinthal to pathways to funnels. Nature Struct. Biol. 4, 10-19 (1997)

  7. Hubless satellite communications networks

    NASA Technical Reports Server (NTRS)

    Robinson, Peter Alan

    1994-01-01

    Frequency Comb Multiple Access (FCMA) is a new combined modulation and multiple access method which will allow cheap hubless Very Small Aperture Terminal (VSAT) networks to be constructed. Theoretical results show bandwidth efficiency and power efficiency improvements over other modulation and multiple access methods. Costs of the VSAT network are reduced dramatically since a hub station is not required.

  8. The deep space network

    NASA Technical Reports Server (NTRS)

    1974-01-01

    The progress is reported of Deep Space Network (DSN) research in the following areas: (1) flight project support, (2) spacecraft/ground communications, (3) station control and operations technology, (4) network control and processing, and (5) deep space stations. A description of the DSN functions and facilities is included.

  9. Optimal Phase Oscillatory Network

    NASA Astrophysics Data System (ADS)

    Follmann, Rosangela

    2013-03-01

    Important topics as preventive detection of epidemics, collective self-organization, information flow and systemic robustness in clusters are typical examples of processes that can be studied in the context of the theory of complex networks. It is an emerging theory in a field, which has recently attracted much interest, involving the synchronization of dynamical systems associated to nodes, or vertices, of the network. Studies have shown that synchronization in oscillatory networks depends not only on the individual dynamics of each element, but also on the combination of the topology of the connections as well as on the properties of the interactions of these elements. Moreover, the response of the network to small damages, caused at strategic points, can enhance the global performance of the whole network. In this presentation we explore an optimal phase oscillatory network altered by an additional term in the coupling function. The application to associative-memory network shows improvement on the correct information retrieval as well as increase of the storage capacity. The inclusion of some small deviations on the nodes, when solutions are attracted to a false state, results in additional enhancement of the performance of the associative-memory network. Supported by FAPESP - Sao Paulo Research Foundation, grant number 2012/12555-4

  10. Electrical Networks: An Introduction

    NASA Astrophysics Data System (ADS)

    Pahwa, S.; Youssef, M.; Scoglio, C.

    A world without electricity is beyond our imagination. Starting from the prehistoric times, man has made much progress in every walk of life. We have become accustomed to getting everything at the flick of a switch, touch of a button, or turn of a knob. While we have become so used to enjoying the benefits of electricity, it is not easy to imagine how electricity travels from its source to our homes and offices. It sometimes has to cover large distances through a complex network of transmission lines and power substations to provide us the facilities and entertainment that we take for granted. This network which transports electricity from the source to the consumers is called the electrical network. The electrical network is a collective term for different components such as transformers, transmission lines, substations, and different stages and sub-networks devoted to generation, transmission, and distribution. Sometimes, there may be sub-transmission and secondary distribution networks too. A simple schematic of an electric network is shown in Fig. 8.1. In the past decade, analysis of the electrical power system as a complex network has been an evolving and challenging topic of research.

  11. The Deep Space Network

    NASA Technical Reports Server (NTRS)

    1979-01-01

    Deep Space Network progress in flight project support, tracking and data acquisition, research and technology, network engineering, hardware and software implementation, and operations is cited. Topics covered include: tracking and ground based navigation; spacecraft/ground communication; station control and operations technology; ground communications; and deep space stations.

  12. Networks; Who, Why, How?

    ERIC Educational Resources Information Center

    Wisconsin Library Bulletin, 1975

    1975-01-01

    The May-June, 1975, issue of Wisconsin Library Bulletin contains articles about library cooperative programs and networks. Subjects covered include: library network planning and definitions of terms; views on the National Commission on Libraries and Information Science program by school, public, academic, and state librarians; the Midwest Library…

  13. A Balanced Memory Network

    PubMed Central

    Roudi, Yasser; Latham, Peter E

    2007-01-01

    A fundamental problem in neuroscience is understanding how working memory—the ability to store information at intermediate timescales, like tens of seconds—is implemented in realistic neuronal networks. The most likely candidate mechanism is the attractor network, and a great deal of effort has gone toward investigating it theoretically. Yet, despite almost a quarter century of intense work, attractor networks are not fully understood. In particular, there are still two unanswered questions. First, how is it that attractor networks exhibit irregular firing, as is observed experimentally during working memory tasks? And second, how many memories can be stored under biologically realistic conditions? Here we answer both questions by studying an attractor neural network in which inhibition and excitation balance each other. Using mean-field analysis, we derive a three-variable description of attractor networks. From this description it follows that irregular firing can exist only if the number of neurons involved in a memory is large. The same mean-field analysis also shows that the number of memories that can be stored in a network scales with the number of excitatory connections, a result that has been suggested for simple models but never shown for realistic ones. Both of these predictions are verified using simulations with large networks of spiking neurons. PMID:17845070

  14. The Deep Space Network

    NASA Technical Reports Server (NTRS)

    1988-01-01

    The Deep Space Network (DSN) is the largest and most sensitive scientific telecommunications and radio navigation network in the world. Its principal responsibilities are to support unmanned interplanetary spacecraft missions and to support radio and radar astronomy observations in the exploration of the solar system and the universe. The DSN facilities and capabilities as of January 1988 are described.

  15. The Community Networking Handbook.

    ERIC Educational Resources Information Center

    Bajjaly, Stephen T.

    This publication outlines the complete community networking process: planning, developing partnerships, funding, marketing, content, public access, and evaluation, and discusses the variety of roles that the local public library can play in this process. Chapter One, "The Importance of Community Networking," describes the importance of community…

  16. Local Area Networks.

    ERIC Educational Resources Information Center

    Marks, Kenneth E.; Nielsen, Steven

    1991-01-01

    Discusses cabling that is needed in local area networks (LANs). Types of cables that may be selected are described, including twisted pair, coaxial cables (or ethernet), and fiber optics; network topologies, the manner in which the cables are laid out, are considered; and cable installation issues are discussed. (LRW)

  17. Language Teaching and Networking.

    ERIC Educational Resources Information Center

    Peterson, Mark

    1997-01-01

    Discusses the impact of computer networking on foreign language teaching and focuses on the competing claims made regarding the value of network-based language learning activity. A description of how internet-based activities operate in the classroom is included. (24 references) (Author/CK)

  18. Network Collaboration with UNIX.

    ERIC Educational Resources Information Center

    Horn, Wm. Dennis

    1993-01-01

    Discusses networking as a collaboration tool in the teaching of technical writing. Argues that some degree of collaboration is innate to all writing, that word processing already facilitates that collaboration, and that networking is the next enhancement to the collaborative process. (RS)

  19. Communication Network Analysis Methods.

    ERIC Educational Resources Information Center

    Farace, Richard V.; Mabee, Timothy

    This paper reviews a variety of analytic procedures that can be applied to network data, discussing the assumptions and usefulness of each procedure when applied to the complexity of human communication. Special attention is paid to the network properties measured or implied by each procedure. Factor analysis and multidimensional scaling are among…

  20. Local Area Networks.

    ERIC Educational Resources Information Center

    Bullard, David

    1983-01-01

    The proliferation of word processors, micro- and minicomputer systems, and other digital office equipment is causing major design changes in existing networks. Local Area Networks (LANs) which have adequately served terminal users in the past must now be redesigned. Implementation at Clemson is described. (MLW)

  1. Wireless Sensors Network (Sensornet)

    NASA Technical Reports Server (NTRS)

    Perotti, J.

    2003-01-01

    The Wireless Sensor Network System presented in this paper provides a flexible reconfigurable architecture that could be used in a broad range of applications. It also provides a sensor network with increased reliability; decreased maintainability costs, and assured data availability by autonomously and automatically reconfiguring to overcome communication interferences.

  2. Community Wireless Networks

    ERIC Educational Resources Information Center

    Feld, Harold

    2005-01-01

    With increasing frequency, communities are seeing the arrival of a new class of noncommercial broadband providers: community wireless networks (CWNs). Utilizing the same wireless technologies that many colleges and universities have used to create wireless networks on campus, CWNs are creating broadband access for free or at costs well below…

  3. Networking Hawaii's School Libraries.

    ERIC Educational Resources Information Center

    Hawaii State Dept. of Education, Honolulu. Office of Instructional Services.

    This guide is designed to assist school librarians in becoming part of the planned statewide school library network in Hawaii. Approaches to the guide for librarians at all stages of planning are suggested, and an overview of the benefits, goals, steps, and historical development are provided together with a model of the networking plan. The steps…

  4. UNESCO as a Network

    ERIC Educational Resources Information Center

    Omolewa, Michael

    2007-01-01

    This study attempts to draw attention to the hitherto neglected, but important, subject of how the United Nations Educational, Scientific, and Cultural Organization (UNESCO), as a network and promoter of other networks, has sought to foster the spirit of cooperation, understanding and partnership among its various Member States through…

  5. Teacher Networks Companion Piece

    ERIC Educational Resources Information Center

    Hopkins, Ami Patel; Rulli, Carolyn; Schiff, Daniel; Fradera, Marina

    2015-01-01

    Network building vitally impacts career development, but in few professions does it impact daily practice more than in teaching. Teacher networks, known as professional learning communities, communities of practice, peer learning circles, virtual professional communities, as well as other names, play a unique and powerful role in education. In…

  6. On Heterogeneous Covert Networks

    NASA Astrophysics Data System (ADS)

    Lindelauf, Roy; Borm, Peter; Hamers, Herbert

    Covert organizations are constantly faced with a tradeoff between secrecy and operational efficiency. Lindelauf, Borm and Hamers [13] developed a theoretical framework to determine optimal homogeneous networks taking the above mentioned considerations explicitly into account. In this paper this framework is put to the test by applying it to the 2002 Jemaah Islamiyah Bali bombing. It is found that most aspects of this covert network can be explained by the theoretical framework. Some interactions however provide a higher risk to the network than others. The theoretical framework on covert networks is extended to accommodate for such heterogeneous interactions. Given a network structure the optimal location of one risky interaction is established. It is shown that the pair of individuals in the organization that should conduct the interaction that presents the highest risk to the organization, is the pair that is the least connected to the remainder of the network. Furthermore, optimal networks given a single risky interaction are approximated and compared. When choosing among a path, star and ring graph it is found that for low order graphs the path graph is best. When increasing the order of graphs under consideration a transition occurs such that the star graph becomes best. It is found that the higher the risk a single interaction presents to the covert network the later this transition from path to star graph occurs.

  7. CAISSON: Interconnect Network Simulator

    NASA Technical Reports Server (NTRS)

    Springer, Paul L.

    2006-01-01

    Cray response to HPCS initiative. Model future petaflop computer interconnect. Parallel discrete event simulation techniques for large scale network simulation. Built on WarpIV engine. Run on laptop and Altix 3000. Can be sized up to 1000 simulated nodes per host node. Good parallel scaling characteristics. Flexible: multiple injectors, arbitration strategies, queue iterators, network topologies.

  8. Networked Teaching and Learning.

    ERIC Educational Resources Information Center

    Benson, Chris, Ed.

    2002-01-01

    This theme issue on networked teaching and learning contains 11 articles written by teachers of English and language arts in Bread Loaf's primarily rural, teacher networks. Most of these narratives describe how teachers have taught writing and literature using online exchanges or teleconferencing involving students in different locations and grade…

  9. K-12 Computer Networking.

    ERIC Educational Resources Information Center

    ERIC Review, 1993

    1993-01-01

    The "ERIC Review" is published three times a year and announces research results, publications, and new programs relevant to each issue's theme topic. This issue explores computer networking in elementary and secondary schools via two principal articles: "Plugging into the 'Net'" (Michael B. Eisenberg and Donald P. Ely); and "Computer Networks for…

  10. Academe's New Girl Network

    ERIC Educational Resources Information Center

    Stent, Angela

    1978-01-01

    A "networking" processing pioneered by the Committee for the Concerns of Women in New England Colleges and Universities, which is establishing a New Girl network to compete with and eventually mesh with the Old Boy system, is described. Lobbying and conference efforts of HERS (Higher Education Resource Services) are reported. (LBH)

  11. Networking: OFFLU example

    Technology Transfer Automated Retrieval System (TEKTRAN)

    World Organization for Animal Health (OIE) and Food and Agriculture Organization (FAO) for the United Nations Influenza Network (OFFLU) is the joint OIE-FAO global network of expertise on animal influenzas: equine, swine, poultry and wild birds. OFFLU aims to reduce negative impacts of animal influ...

  12. Hanford Seismic Network

    SciTech Connect

    Reidel, S.P.; Hartshorn, D.C.

    1997-05-01

    This report describes the Hanford Seismic Network. The network consists of two instrument arrays: seismometers and strong motion accelerometers. The seismometers determine the location and magnitude of earthquakes, and the strong motion accelerometers determine ground motion. Together these instruments arrays comply with the intent of DOE Order 5480.20, Natural Phenomena Hazards Mitigation.

  13. Optical Access Networks

    NASA Astrophysics Data System (ADS)

    Zheng, Jun; Ansari, Nirwan

    2005-01-01

    Call for Papers: Optical Access Networks

    Guest Editors Jun Zheng, University of Ottawa Nirwan Ansari, New Jersey Institute of Technology

    Submission Deadline: 1 June 2005

    Background

    With the wide deployment of fiber-optic technology over the past two decades, we have witnessed a tremendous growth of bandwidth capacity in the backbone networks of today's telecommunications infrastructure. However, access networks, which cover the "last-mile" areas and serve numerous residential and small business users, have not been scaled up commensurately. The local subscriber lines for telephone and cable television are still using twisted pairs and coaxial cables. Most residential connections to the Internet are still through dial-up modems operating at a low speed on twisted pairs. As the demand for access bandwidth increases with emerging high-bandwidth applications, such as distance learning, high-definition television (HDTV), and video on demand (VoD), the last-mile access networks have become a bandwidth bottleneck in today's telecommunications infrastructure. To ease this bottleneck, it is imperative to provide sufficient bandwidth capacity in the access networks to open the bottleneck and thus present more opportunities for the provisioning of multiservices. Optical access solutions promise huge bandwidth to service providers and low-cost high-bandwidth services to end users and are therefore widely considered the technology of choice for next-generation access networks. To realize the vision of optical access networks, however, many key issues still need to be addressed, such as network architectures, signaling protocols, and implementation standards. The major challenges lie in the fact that an optical solution must be not only robust, scalable, and flexible, but also implemented at a low cost comparable to that of existing access solutions in order to increase the

  14. Easily repairable networks

    NASA Astrophysics Data System (ADS)

    Fink, Thomas

    2015-03-01

    We introduce a simple class of distribution networks which withstand damage by being repairable instead of redundant. Instead of asking how hard it is to disconnect nodes through damage, we ask how easy it is to reconnect nodes after damage. We prove that optimal networks on regular lattices have an expected cost of reconnection proportional to the lattice length, and that such networks have exactly three levels of structural hierarchy. We extend our results to networks subject to repeated attacks, in which the repairs themselves must be repairable. We find that, in exchange for a modest increase in repair cost, such networks are able to withstand any number of attacks. We acknowledge support from the Defense Threat Reduction Agency, BCG and EU FP7 (Growthcom).

  15. Modular Brain Networks

    PubMed Central

    Sporns, Olaf; Betzel, Richard F.

    2016-01-01

    The development of new technologies for mapping structural and functional brain connectivity has led to the creation of comprehensive network maps of neuronal circuits and systems. The architecture of these brain networks can be examined and analyzed with a large variety of graph theory tools. Methods for detecting modules, or network communities, are of particular interest because they uncover major building blocks or subnetworks that are particularly densely connected, often corresponding to specialized functional components. A large number of methods for community detection have become available and are now widely applied in network neuroscience. This article first surveys a number of these methods, with an emphasis on their advantages and shortcomings; then it summarizes major findings on the existence of modules in both structural and functional brain networks and briefly considers their potential functional roles in brain evolution, wiring minimization, and the emergence of functional specialization and complex dynamics. PMID:26393868

  16. Collective network routing

    SciTech Connect

    Hoenicke, Dirk

    2014-12-02

    Disclosed are a unified method and apparatus to classify, route, and process injected data packets into a network so as to belong to a plurality of logical networks, each implementing a specific flow of data on top of a common physical network. The method allows to locally identify collectives of packets for local processing, such as the computation of the sum, difference, maximum, minimum, or other logical operations among the identified packet collective. Packets are injected together with a class-attribute and an opcode attribute. Network routers, employing the described method, use the packet attributes to look-up the class-specific route information from a local route table, which contains the local incoming and outgoing directions as part of the specifically implemented global data flow of the particular virtual network.

  17. Concordant Chemical Reaction Networks

    PubMed Central

    Shinar, Guy; Feinberg, Martin

    2015-01-01

    We describe a large class of chemical reaction networks, those endowed with a subtle structural property called concordance. We show that the class of concordant networks coincides precisely with the class of networks which, when taken with any weakly monotonic kinetics, invariably give rise to kinetic systems that are injective — a quality that, among other things, precludes the possibility of switch-like transitions between distinct positive steady states. We also provide persistence characteristics of concordant networks, instability implications of discordance, and consequences of stronger variants of concordance. Some of our results are in the spirit of recent ones by Banaji and Craciun, but here we do not require that every species suffer a degradation reaction. This is especially important in studying biochemical networks, for which it is rare to have all species degrade. PMID:22659063

  18. Motifs in brain networks.

    PubMed

    Sporns, Olaf; Kötter, Rolf

    2004-11-01

    Complex brains have evolved a highly efficient network architecture whose structural connectivity is capable of generating a large repertoire of functional states. We detect characteristic network building blocks (structural and functional motifs) in neuroanatomical data sets and identify a small set of structural motifs that occur in significantly increased numbers. Our analysis suggests the hypothesis that brain networks maximize both the number and the diversity of functional motifs, while the repertoire of structural motifs remains small. Using functional motif number as a cost function in an optimization algorithm, we obtain network topologies that resemble real brain networks across a broad spectrum of structural measures, including small-world attributes. These results are consistent with the hypothesis that highly evolved neural architectures are organized to maximize functional repertoires and to support highly efficient integration of information.

  19. Motifs in Brain Networks

    PubMed Central

    2004-01-01

    Complex brains have evolved a highly efficient network architecture whose structural connectivity is capable of generating a large repertoire of functional states. We detect characteristic network building blocks (structural and functional motifs) in neuroanatomical data sets and identify a small set of structural motifs that occur in significantly increased numbers. Our analysis suggests the hypothesis that brain networks maximize both the number and the diversity of functional motifs, while the repertoire of structural motifs remains small. Using functional motif number as a cost function in an optimization algorithm, we obtain network topologies that resemble real brain networks across a broad spectrum of structural measures, including small-world attributes. These results are consistent with the hypothesis that highly evolved neural architectures are organized to maximize functional repertoires and to support highly efficient integration of information. PMID:15510229

  20. Deterministic hierarchical networks

    NASA Astrophysics Data System (ADS)

    Barrière, L.; Comellas, F.; Dalfó, C.; Fiol, M. A.

    2016-06-01

    It has been shown that many networks associated with complex systems are small-world (they have both a large local clustering coefficient and a small diameter) and also scale-free (the degrees are distributed according to a power law). Moreover, these networks are very often hierarchical, as they describe the modularity of the systems that are modeled. Most of the studies for complex networks are based on stochastic methods. However, a deterministic method, with an exact determination of the main relevant parameters of the networks, has proven useful. Indeed, this approach complements and enhances the probabilistic and simulation techniques and, therefore, it provides a better understanding of the modeled systems. In this paper we find the radius, diameter, clustering coefficient and degree distribution of a generic family of deterministic hierarchical small-world scale-free networks that has been considered for modeling real-life complex systems.

  1. Modeling semiflexible polymer networks

    NASA Astrophysics Data System (ADS)

    Broedersz, C. P.; MacKintosh, F. C.

    2014-07-01

    This is an overview of theoretical approaches to semiflexible polymers and their networks. Such semiflexible polymers have large bending rigidities that can compete with the entropic tendency of a chain to crumple up into a random coil. Many studies on semiflexible polymers and their assemblies have been motivated by their importance in biology. Indeed, cross-linked networks of semiflexible polymers form a major structural component of tissue and living cells. Reconstituted networks of such biopolymers have emerged as a new class of biological soft matter systems with remarkable material properties, which have spurred many of the theoretical developments discussed here. Starting from the mechanics and dynamics of individual semiflexible polymers, the physics of semiflexible bundles, entangled solutions, and disordered cross-linked networks are reviewed. Finally, recent developments on marginally stable fibrous networks, which exhibit critical behavior similar to other marginal systems such as jammed soft matter, are discussed.

  2. Controllability of complex networks.

    PubMed

    Liu, Yang-Yu; Slotine, Jean-Jacques; Barabási, Albert-László

    2011-05-12

    The ultimate proof of our understanding of natural or technological systems is reflected in our ability to control them. Although control theory offers mathematical tools for steering engineered and natural systems towards a desired state, a framework to control complex self-organized systems is lacking. Here we develop analytical tools to study the controllability of an arbitrary complex directed network, identifying the set of driver nodes with time-dependent control that can guide the system's entire dynamics. We apply these tools to several real networks, finding that the number of driver nodes is determined mainly by the network's degree distribution. We show that sparse inhomogeneous networks, which emerge in many real complex systems, are the most difficult to control, but that dense and homogeneous networks can be controlled using a few driver nodes. Counterintuitively, we find that in both model and real systems the driver nodes tend to avoid the high-degree nodes.

  3. Network Class Superposition Analyses

    PubMed Central

    Pearson, Carl A. B.; Zeng, Chen; Simha, Rahul

    2013-01-01

    Networks are often used to understand a whole system by modeling the interactions among its pieces. Examples include biomolecules in a cell interacting to provide some primary function, or species in an environment forming a stable community. However, these interactions are often unknown; instead, the pieces' dynamic states are known, and network structure must be inferred. Because observed function may be explained by many different networks (e.g., for the yeast cell cycle process [1]), considering dynamics beyond this primary function means picking a single network or suitable sample: measuring over all networks exhibiting the primary function is computationally infeasible. We circumvent that obstacle by calculating the network class ensemble. We represent the ensemble by a stochastic matrix , which is a transition-by-transition superposition of the system dynamics for each member of the class. We present concrete results for derived from Boolean time series dynamics on networks obeying the Strong Inhibition rule, by applying to several traditional questions about network dynamics. We show that the distribution of the number of point attractors can be accurately estimated with . We show how to generate Derrida plots based on . We show that -based Shannon entropy outperforms other methods at selecting experiments to further narrow the network structure. We also outline an experimental test of predictions based on . We motivate all of these results in terms of a popular molecular biology Boolean network model for the yeast cell cycle, but the methods and analyses we introduce are general. We conclude with open questions for , for example, application to other models, computational considerations when scaling up to larger systems, and other potential analyses. PMID:23565141

  4. Network class superposition analyses.

    PubMed

    Pearson, Carl A B; Zeng, Chen; Simha, Rahul

    2013-01-01

    Networks are often used to understand a whole system by modeling the interactions among its pieces. Examples include biomolecules in a cell interacting to provide some primary function, or species in an environment forming a stable community. However, these interactions are often unknown; instead, the pieces' dynamic states are known, and network structure must be inferred. Because observed function may be explained by many different networks (e.g., ≈ 10(30) for the yeast cell cycle process), considering dynamics beyond this primary function means picking a single network or suitable sample: measuring over all networks exhibiting the primary function is computationally infeasible. We circumvent that obstacle by calculating the network class ensemble. We represent the ensemble by a stochastic matrix T, which is a transition-by-transition superposition of the system dynamics for each member of the class. We present concrete results for T derived from boolean time series dynamics on networks obeying the Strong Inhibition rule, by applying T to several traditional questions about network dynamics. We show that the distribution of the number of point attractors can be accurately estimated with T. We show how to generate Derrida plots based on T. We show that T-based Shannon entropy outperforms other methods at selecting experiments to further narrow the network structure. We also outline an experimental test of predictions based on T. We motivate all of these results in terms of a popular molecular biology boolean network model for the yeast cell cycle, but the methods and analyses we introduce are general. We conclude with open questions for T, for example, application to other models, computational considerations when scaling up to larger systems, and other potential analyses. PMID:23565141

  5. Improved Autoassociative Neural Networks

    NASA Technical Reports Server (NTRS)

    Hand, Charles

    2003-01-01

    Improved autoassociative neural networks, denoted nexi, have been proposed for use in controlling autonomous robots, including mobile exploratory robots of the biomorphic type. In comparison with conventional autoassociative neural networks, nexi would be more complex but more capable in that they could be trained to do more complex tasks. A nexus would use bit weights and simple arithmetic in a manner that would enable training and operation without a central processing unit, programs, weight registers, or large amounts of memory. Only a relatively small amount of memory (to hold the bit weights) and a simple logic application- specific integrated circuit would be needed. A description of autoassociative neural networks is prerequisite to a meaningful description of a nexus. An autoassociative network is a set of neurons that are completely connected in the sense that each neuron receives input from, and sends output to, all the other neurons. (In some instantiations, a neuron could also send output back to its own input terminal.) The state of a neuron is completely determined by the inner product of its inputs with weights associated with its input channel. Setting the weights sets the behavior of the network. The neurons of an autoassociative network are usually regarded as comprising a row or vector. Time is a quantized phenomenon for most autoassociative networks in the sense that time proceeds in discrete steps. At each time step, the row of neurons forms a pattern: some neurons are firing, some are not. Hence, the current state of an autoassociative network can be described with a single binary vector. As time goes by, the network changes the vector. Autoassociative networks move vectors over hyperspace landscapes of possibilities.

  6. Network of networks in Linux operating system

    NASA Astrophysics Data System (ADS)

    Wang, Haoqin; Chen, Zhen; Xiao, Guanping; Zheng, Zheng

    2016-04-01

    Operating system represents one of the most complex man-made systems. In this paper, we analyze Linux Operating System (LOS) as a complex network via modeling functions as nodes and function calls as edges. It is found that for the LOS network and modularized components within it, the out-degree follows an exponential distribution and the in-degree follows a power-law distribution. For better understanding the underlying design principles of LOS, we explore the coupling correlations of components in LOS from aspects of topology and function. The result shows that the component for device drivers has a strong manifestation in topology while a weak manifestation in function. However, the component for process management shows the contrary phenomenon. Moreover, in an effort to investigate the impact of system failures on networks, we make a comparison between the networks traced from normal and failure status of LOS. This leads to a conclusion that the failure will change function calls which should be executed in normal status and introduce new function calls in the meanwhile.

  7. Tinnitus: network pathophysiology-network pharmacology

    PubMed Central

    Elgoyhen, Ana B.; Langguth, Berthold; Vanneste, Sven; De Ridder, Dirk

    2012-01-01

    Tinnitus, the phantom perception of sound, is a prevalent disorder. One in 10 adults has clinically significant subjective tinnitus, and for one in 100, tinnitus severely affects their quality of life. Despite the significant unmet clinical need for a safe and effective drug targeting tinnitus relief, there is currently not a single Food and Drug Administration (FDA)-approved drug on the market. The search for drugs that target tinnitus is hampered by the lack of a deep knowledge of the underlying neural substrates of this pathology. Recent studies are increasingly demonstrating that, as described for other central nervous system (CNS) disorders, tinnitus is a pathology of brain networks. The application of graph theoretical analysis to brain networks has recently provided new information concerning their topology, their robustness and their vulnerability to attacks. Moreover, the philosophy behind drug design and pharmacotherapy in CNS pathologies is changing from that of “magic bullets” that target individual chemoreceptors or “disease-causing genes” into that of “magic shotguns,” “promiscuous” or “dirty drugs” that target “disease-causing networks,” also known as network pharmacology. In the present work we provide some insight into how this knowledge could be applied to tinnitus pathophysiology and pharmacotherapy. PMID:22291622

  8. Extracting information from multiplex networks.

    PubMed

    Iacovacci, Jacopo; Bianconi, Ginestra

    2016-06-01

    Multiplex networks are generalized network structures that are able to describe networks in which the same set of nodes are connected by links that have different connotations. Multiplex networks are ubiquitous since they describe social, financial, engineering, and biological networks as well. Extending our ability to analyze complex networks to multiplex network structures increases greatly the level of information that is possible to extract from big data. For these reasons, characterizing the centrality of nodes in multiplex networks and finding new ways to solve challenging inference problems defined on multiplex networks are fundamental questions of network science. In this paper, we discuss the relevance of the Multiplex PageRank algorithm for measuring the centrality of nodes in multilayer networks and we characterize the utility of the recently introduced indicator function Θ̃(S) for describing their mesoscale organization and community structure. As working examples for studying these measures, we consider three multiplex network datasets coming for social science. PMID:27368796

  9. Extracting information from multiplex networks.

    PubMed

    Iacovacci, Jacopo; Bianconi, Ginestra

    2016-06-01

    Multiplex networks are generalized network structures that are able to describe networks in which the same set of nodes are connected by links that have different connotations. Multiplex networks are ubiquitous since they describe social, financial, engineering, and biological networks as well. Extending our ability to analyze complex networks to multiplex network structures increases greatly the level of information that is possible to extract from big data. For these reasons, characterizing the centrality of nodes in multiplex networks and finding new ways to solve challenging inference problems defined on multiplex networks are fundamental questions of network science. In this paper, we discuss the relevance of the Multiplex PageRank algorithm for measuring the centrality of nodes in multilayer networks and we characterize the utility of the recently introduced indicator function Θ̃(S) for describing their mesoscale organization and community structure. As working examples for studying these measures, we consider three multiplex network datasets coming for social science.

  10. Extracting information from multiplex networks

    NASA Astrophysics Data System (ADS)

    Iacovacci, Jacopo; Bianconi, Ginestra

    2016-06-01

    Multiplex networks are generalized network structures that are able to describe networks in which the same set of nodes are connected by links that have different connotations. Multiplex networks are ubiquitous since they describe social, financial, engineering, and biological networks as well. Extending our ability to analyze complex networks to multiplex network structures increases greatly the level of information that is possible to extract from big data. For these reasons, characterizing the centrality of nodes in multiplex networks and finding new ways to solve challenging inference problems defined on multiplex networks are fundamental questions of network science. In this paper, we discuss the relevance of the Multiplex PageRank algorithm for measuring the centrality of nodes in multilayer networks and we characterize the utility of the recently introduced indicator function Θ ˜ S for describing their mesoscale organization and community structure. As working examples for studying these measures, we consider three multiplex network datasets coming for social science.

  11. Closeness Possible through Computer Networking.

    ERIC Educational Resources Information Center

    Dodd, Julie E.

    1989-01-01

    Points out the benefits of computer networking for scholastic journalism. Discusses three systems currently offering networking possibilities for publications: the Student Press Information Network; the Youth Communication Service; and the Dow Jones Newspaper Fund's electronic mail system. (MS)

  12. No Pet or Their Person Left Behind: Increasing the Disaster Resilience of Vulnerable Groups through Animal Attachment, Activities and Networks

    PubMed Central

    Thompson, Kirrilly; Every, Danielle; Rainbird, Sophia; Cornell, Victoria; Smith, Bradley; Trigg, Joshua

    2014-01-01

    Simple Summary The potential for reconfiguring pet ownership from a risk factor to a protective factor for natural disaster survival has been recently proposed. But how might this resilience-building proposition apply to members of the community who are already considered vulnerable? This article addresses this important question by synthesizing information about what makes seven particular groups vulnerable, the challenges to increasing their resilience and how animals figure in their lives. It concludes that animal attachment could provide a novel conduit for accessing, communicating with and motivating vulnerable people to engage in resilience building behaviors that promote survival and facilitate recovery. Abstract Increased vulnerability to natural disasters has been associated with particular groups in the community. This includes those who are considered de facto vulnerable (children, older people, those with disabilities etc.) and those who own pets (not to mention pets themselves). The potential for reconfiguring pet ownership from a risk factor to a protective factor for natural disaster survival has been recently proposed. But how might this resilience-building proposition apply to vulnerable members of the community who own pets or other animals? This article addresses this important question by synthesizing information about what makes particular groups vulnerable, the challenges to increasing their resilience and how animals figure in their lives. Despite different vulnerabilities, animals were found to be important to the disaster resilience of seven vulnerable groups in Australia. Animal attachment and animal-related activities and networks are identified as underexplored devices for disseminating or ‘piggybacking’ disaster-related information and engaging vulnerable people in resilience building behaviors (in addition to including animals in disaster planning initiatives in general). Animals may provide the kind of innovative approach required

  13. The Emergence of the Open Networked ``i-Learning'' Model

    NASA Astrophysics Data System (ADS)

    Elia, Gianluca

    The most significant forces that are changing the business world and the society behaviors in this beginning of the twenty-first century can be identified into the globalization of the economy, technological evolution and convergence, change of the workers' expectations, workplace diversity and mobility, and mostly, knowledge and learning as major organizational assets. But which type of ­learning dynamics must be nurtured and pursued within the organizations, today, in order to generate valuable knowledge and its effective applications? After a brief discussion on the main changes observable in management, ICT and society/workplace in the last years, this chapter aims to answer to this question, through the proposition of the “Π-shaped” profile (a new professional archetype for leading change), and through the discussion of the open networked “i-Learning” model (a new framework to “incubate” innovation in learning processes). Actually, the “i” stands for “innovation” (to highlight the nature of the impact on traditional ­learning model), but also it stands for “incubation” (to underline the urgency to have new environments in which incubating new professional profiles). Specifically, the main key characteristics at the basis of the innovation of the learning processes will be ­presented and described, by highlighting the managerial, technological and societal aspects of their nature. A set of operational guidelines will be also ­provided to ­activate and sustain the innovation process, so implementing changes in the strategic dimensions of the model. Finally, the “i-Learning Radar” is presented as an operational tool to design, communicate and control an “i-Learning experience”. This tool is represented by a radar diagram with six strategic dimensions of a ­learning initiative.

  14. Neural networks for aircraft control

    NASA Technical Reports Server (NTRS)

    Linse, Dennis

    1990-01-01

    Current research in Artificial Neural Networks indicates that networks offer some potential advantages in adaptation and fault tolerance. This research is directed at determining the possible applicability of neural networks to aircraft control. The first application will be to aircraft trim. Neural network node characteristics, network topology and operation, neural network learning and example histories using neighboring optimal control with a neural net are discussed.

  15. Correlation dimension of complex networks.

    PubMed

    Lacasa, Lucas; Gómez-Gardeñes, Jesús

    2013-04-19

    We propose a new measure to characterize the dimension of complex networks based on the ergodic theory of dynamical systems. This measure is derived from the correlation sum of a trajectory generated by a random walker navigating the network, and extends the classical Grassberger-Procaccia algorithm to the context of complex networks. The method is validated with reliable results for both synthetic networks and real-world networks such as the world air-transportation network or urban networks, and provides a computationally fast way for estimating the dimensionality of networks which only relies on the local information provided by the walkers.

  16. Robustness of airline route networks

    NASA Astrophysics Data System (ADS)

    Lordan, Oriol; Sallan, Jose M.; Escorihuela, Nuria; Gonzalez-Prieto, David

    2016-03-01

    Airlines shape their route network by defining their routes through supply and demand considerations, paying little attention to network performance indicators, such as network robustness. However, the collapse of an airline network can produce high financial costs for the airline and all its geographical area of influence. The aim of this study is to analyze the topology and robustness of the network route of airlines following Low Cost Carriers (LCCs) and Full Service Carriers (FSCs) business models. Results show that FSC hubs are more central than LCC bases in their route network. As a result, LCC route networks are more robust than FSC networks.

  17. A Network Synthesis Model for Generating Protein Interaction Network Families

    PubMed Central

    Sahraeian, Sayed Mohammad Ebrahim; Yoon, Byung-Jun

    2012-01-01

    In this work, we introduce a novel network synthesis model that can generate families of evolutionarily related synthetic protein–protein interaction (PPI) networks. Given an ancestral network, the proposed model generates the network family according to a hypothetical phylogenetic tree, where the descendant networks are obtained through duplication and divergence of their ancestors, followed by network growth using network evolution models. We demonstrate that this network synthesis model can effectively create synthetic networks whose internal and cross-network properties closely resemble those of real PPI networks. The proposed model can serve as an effective framework for generating comprehensive benchmark datasets that can be used for reliable performance assessment of comparative network analysis algorithms. Using this model, we constructed a large-scale network alignment benchmark, called NAPAbench, and evaluated the performance of several representative network alignment algorithms. Our analysis clearly shows the relative performance of the leading network algorithms, with their respective advantages and disadvantages. The algorithm and source code of the network synthesis model and the network alignment benchmark NAPAbench are publicly available at http://www.ece.tamu.edu/bjyoon/NAPAbench/. PMID:22912671

  18. Scalable Virtual Network Mapping Algorithm for Internet-Scale Networks

    NASA Astrophysics Data System (ADS)

    Yang, Qiang; Wu, Chunming; Zhang, Min

    The proper allocation of network resources from a common physical substrate to a set of virtual networks (VNs) is one of the key technical challenges of network virtualization. While a variety of state-of-the-art algorithms have been proposed in an attempt to address this issue from different facets, the challenge still remains in the context of large-scale networks as the existing solutions mainly perform in a centralized manner which requires maintaining the overall and up-to-date information of the underlying substrate network. This implies the restricted scalability and computational efficiency when the network scale becomes large. This paper tackles the virtual network mapping problem and proposes a novel hierarchical algorithm in conjunction with a substrate network decomposition approach. By appropriately transforming the underlying substrate network into a collection of sub-networks, the hierarchical virtual network mapping algorithm can be carried out through a global virtual network mapping algorithm (GVNMA) and a local virtual network mapping algorithm (LVNMA) operated in the network central server and within individual sub-networks respectively with their cooperation and coordination as necessary. The proposed algorithm is assessed against the centralized approaches through a set of numerical simulation experiments for a range of network scenarios. The results show that the proposed hierarchical approach can be about 5-20 times faster for VN mapping tasks than conventional centralized approaches with acceptable communication overhead between GVNCA and LVNCA for all examined networks, whilst performs almost as well as the centralized solutions.

  19. Optical Network Testbeds Workshop

    SciTech Connect

    Joe Mambretti

    2007-06-01

    This is the summary report of the third annual Optical Networking Testbed Workshop (ONT3), which brought together leading members of the international advanced research community to address major challenges in creating next generation communication services and technologies. Networking research and development (R&D) communities throughout the world continue to discover new methods and technologies that are enabling breakthroughs in advanced communications. These discoveries are keystones for building the foundation of the future economy, which requires the sophisticated management of extremely large qualities of digital information through high performance communications. This innovation is made possible by basic research and experiments within laboratories and on specialized testbeds. Initial network research and development initiatives are driven by diverse motives, including attempts to solve existing complex problems, the desire to create powerful new technologies that do not exist using traditional methods, and the need to create tools to address specific challenges, including those mandated by large scale science or government agency mission agendas. Many new discoveries related to communications technologies transition to wide-spread deployment through standards organizations and commercialization. These transition paths allow for new communications capabilities that drive many sectors of the digital economy. In the last few years, networking R&D has increasingly focused on advancing multiple new capabilities enabled by next generation optical networking. Both US Federal networking R&D and other national R&D initiatives, such as those organized by the National Institute of Information and Communications Technology (NICT) of Japan are creating optical networking technologies that allow for new, powerful communication services. Among the most promising services are those based on new types of multi-service or hybrid networks, which use new optical networking

  20. A quantum access network.

    PubMed

    Fröhlich, Bernd; Dynes, James F; Lucamarini, Marco; Sharpe, Andrew W; Yuan, Zhiliang; Shields, Andrew J

    2013-09-01

    The theoretically proven security of quantum key distribution (QKD) could revolutionize the way in which information exchange is protected in the future. Several field tests of QKD have proven it to be a reliable technology for cryptographic key exchange and have demonstrated nodal networks of point-to-point links. However, until now no convincing answer has been given to the question of how to extend the scope of QKD beyond niche applications in dedicated high security networks. Here we introduce and experimentally demonstrate the concept of a 'quantum access network': based on simple and cost-effective telecommunication technologies, the scheme can greatly expand the number of users in quantum networks and therefore vastly broaden their appeal. We show that a high-speed single-photon detector positioned at a network node can be shared between up to 64 users for exchanging secret keys with the node, thereby significantly reducing the hardware requirements for each user added to the network. This point-to-multipoint architecture removes one of the main obstacles restricting the widespread application of QKD. It presents a viable method for realizing multi-user QKD networks with efficient use of resources, and brings QKD closer to becoming a widespread technology. PMID:24005413

  1. Interictal networks in magnetoencephalography.

    PubMed

    Malinowska, Urszula; Badier, Jean-Michel; Gavaret, Martine; Bartolomei, Fabrice; Chauvel, Patrick; Bénar, Christian-George

    2014-06-01

    Epileptic networks involve complex relationships across several brain areas. Such networks have been shown on intracerebral EEG (stereotaxic EEG, SEEG), an invasive technique. Magnetoencephalography (MEG) is a noninvasive tool, which was recently proven to be efficient for localizing the generators of epileptiform discharges. However, despite the importance of characterizing non-invasively network aspects in partial epilepsies, only few studies have attempted to retrieve fine spatiotemporal dynamics of interictal discharges with MEG. Our goal was to assess the relevance of magnetoencephalography for detecting and characterizing the brain networks involved in interictal epileptic discharges. We propose here a semi-automatic method based on independent component analysis (ICA) and on co-occurrence of events across components. The method was evaluated in a series of seven patients by comparing its results with networks identified in SEEG. On both MEG and SEEG, we found that interictal discharges can involve remote regions which are acting in synchrony. More regions were identified in SEEG (38 in total) than in MEG (20). All MEG regions were confirmed by SEEG when an electrode was present in the vicinity. In all patients, at least one region could be identified as leading according to our criteria. A majority (71%) of MEG leaders were confirmed by SEEG. We have therefore shown that MEG measurements can extract a significant proportion of the networks visible in SEEG. This suggests that MEG can be a useful tool for defining noninvasively interictal epileptic networks, in terms of regions and patterns of connectivity, in search for a "primary irritative zone".

  2. Toward Optimal Transport Networks

    NASA Technical Reports Server (NTRS)

    Alexandrov, Natalia; Kincaid, Rex K.; Vargo, Erik P.

    2008-01-01

    Strictly evolutionary approaches to improving the air transport system a highly complex network of interacting systems no longer suffice in the face of demand that is projected to double or triple in the near future. Thus evolutionary approaches should be augmented with active design methods. The ability to actively design, optimize and control a system presupposes the existence of predictive modeling and reasonably well-defined functional dependences between the controllable variables of the system and objective and constraint functions for optimization. Following recent advances in the studies of the effects of network topology structure on dynamics, we investigate the performance of dynamic processes on transport networks as a function of the first nontrivial eigenvalue of the network's Laplacian, which, in turn, is a function of the network s connectivity and modularity. The last two characteristics can be controlled and tuned via optimization. We consider design optimization problem formulations. We have developed a flexible simulation of network topology coupled with flows on the network for use as a platform for computational experiments.

  3. Complex Semantic Networks

    NASA Astrophysics Data System (ADS)

    Teixeira, G. M.; Aguiar, M. S. F.; Carvalho, C. F.; Dantas, D. R.; Cunha, M. V.; Morais, J. H. M.; Pereira, H. B. B.; Miranda, J. G. V.

    Verbal language is a dynamic mental process. Ideas emerge by means of the selection of words from subjective and individual characteristics throughout the oral discourse. The goal of this work is to characterize the complex network of word associations that emerge from an oral discourse from a discourse topic. Because of that, concepts of associative incidence and fidelity have been elaborated and represented the probability of occurrence of pairs of words in the same sentence in the whole oral discourse. Semantic network of words associations were constructed, where the words are represented as nodes and the edges are created when the incidence-fidelity index between pairs of words exceeds a numerical limit (0.001). Twelve oral discourses were studied. The networks generated from these oral discourses present a typical behavior of complex networks and their indices were calculated and their topologies characterized. The indices of these networks obtained from each incidence-fidelity limit exhibit a critical value in which the semantic network has maximum conceptual information and minimum residual associations. Semantic networks generated by this incidence-fidelity limit depict a pattern of hierarchical classes that represent the different contexts used in the oral discourse.

  4. Balanced Centrality of Networks.

    PubMed

    Debono, Mark; Lauri, Josef; Sciriha, Irene

    2014-01-01

    There is an age-old question in all branches of network analysis. What makes an actor in a network important, courted, or sought? Both Crossley and Bonacich contend that rather than its intrinsic wealth or value, an actor's status lies in the structures of its interactions with other actors. Since pairwise relation data in a network can be stored in a two-dimensional array or matrix, graph theory and linear algebra lend themselves as great tools to gauge the centrality (interpreted as importance, power, or popularity, depending on the purpose of the network) of each actor. We express known and new centralities in terms of only two matrices associated with the network. We show that derivations of these expressions can be handled exclusively through the main eigenvectors (not orthogonal to the all-one vector) associated with the adjacency matrix. We also propose a centrality vector (SWIPD) which is a linear combination of the square, walk, power, and degree centrality vectors with weightings of the various centralities depending on the purpose of the network. By comparing actors' scores for various weightings, a clear understanding of which actors are most central is obtained. Moreover, for threshold networks, the (SWIPD) measure turns out to be independent of the weightings. PMID:27437494

  5. Balanced Centrality of Networks

    PubMed Central

    Sciriha, Irene

    2014-01-01

    There is an age-old question in all branches of network analysis. What makes an actor in a network important, courted, or sought? Both Crossley and Bonacich contend that rather than its intrinsic wealth or value, an actor's status lies in the structures of its interactions with other actors. Since pairwise relation data in a network can be stored in a two-dimensional array or matrix, graph theory and linear algebra lend themselves as great tools to gauge the centrality (interpreted as importance, power, or popularity, depending on the purpose of the network) of each actor. We express known and new centralities in terms of only two matrices associated with the network. We show that derivations of these expressions can be handled exclusively through the main eigenvectors (not orthogonal to the all-one vector) associated with the adjacency matrix. We also propose a centrality vector (SWIPD) which is a linear combination of the square, walk, power, and degree centrality vectors with weightings of the various centralities depending on the purpose of the network. By comparing actors' scores for various weightings, a clear understanding of which actors are most central is obtained. Moreover, for threshold networks, the (SWIPD) measure turns out to be independent of the weightings. PMID:27437494

  6. Stochastically evolving networks

    NASA Astrophysics Data System (ADS)

    Chan, Derek Y.; Hughes, Barry D.; Leong, Alex S.; Reed, William J.

    2003-12-01

    We discuss a class of models for the evolution of networks in which new nodes are recruited into the network at random times, and links between existing nodes that are not yet directly connected may also form at random times. The class contains both models that produce “small-world” networks and less tightly linked models. We produce both trees, appropriate in certain biological applications, and networks in which closed loops can appear, which model communication networks and networks of human sexual interactions. One of our models is closely related to random recursive trees, and some exact results known in that context can be exploited. The other models are more subtle and difficult to analyze. Our analysis includes a number of exact results for moments, correlations, and distributions of coordination number and network size. We report simulations and also discuss some mean-field approximations. If the system has evolved for a long time and the state of a random node (which thus has a random age) is observed, power-law distributions for properties of the system arise in some of these models.

  7. Neural network machine vision

    SciTech Connect

    Fox, R.O.; Czerniejewski, F.; Fluet, F.; Mitchell, E.

    1988-09-01

    Gould, Inc. and Nestor, Inc. cooperated on a joint development project to combine machine vision technology with neural network technology. The result is a machine vision system which can be trained by an inexperienced operator to perform qualitative classification. The hardware preprocessor reduces the information in the 2D camera image from 122,880 (i.e. 512 x 240) bytes to several hundred bytes in 64 milliseconds. The output of the preprocessor, which is in the format of connected lines, is fed to the first neural network. This neural network performs feature recognition. The output of the first neural network is a probability map. This map is fed to the input of the second neural network which performs object verification. The output of the second neural network is the object location and classification in the field of view. This information can optionally be fed into a third neural network which analyzes spatial relationships of objects in the field of view. The final output is a classification, by quality level, or by style. The system has been tested on applications ranging from the grading of plywood and the grading of paper to the sorting of fabricated metal parts. Specific application examples are presented.

  8. Wireless mesh networks.

    PubMed

    Wang, Xinheng

    2008-01-01

    Wireless telemedicine using GSM and GPRS technologies can only provide low bandwidth connections, which makes it difficult to transmit images and video. Satellite or 3G wireless transmission provides greater bandwidth, but the running costs are high. Wireless networks (WLANs) appear promising, since they can supply high bandwidth at low cost. However, the WLAN technology has limitations, such as coverage. A new wireless networking technology named the wireless mesh network (WMN) overcomes some of the limitations of the WLAN. A WMN combines the characteristics of both a WLAN and ad hoc networks, thus forming an intelligent, large scale and broadband wireless network. These features are attractive for telemedicine and telecare because of the ability to provide data, voice and video communications over a large area. One successful wireless telemedicine project which uses wireless mesh technology is the Emergency Room Link (ER-LINK) in Tucson, Arizona, USA. There are three key characteristics of a WMN: self-organization, including self-management and self-healing; dynamic changes in network topology; and scalability. What we may now see is a shift from mobile communication and satellite systems for wireless telemedicine to the use of wireless networks based on mesh technology, since the latter are very attractive in terms of cost, reliability and speed.

  9. Simulated Associating Polymer Networks

    NASA Astrophysics Data System (ADS)

    Billen, Joris

    Telechelic associating polymer networks consist of polymer chains terminated by endgroups that have a different chemical composition than the polymer backbone. When dissolved in a solution, the endgroups cluster together to form aggregates. At low temperature, a strongly connected reversible network is formed and the system behaves like a gel. Telechelic networks are of interest since they are representative for biopolymer networks (e.g. F-actin) and are widely used in medical applications (e.g. hydrogels for tissue engineering, wound dressings) and consumer products (e.g. contact lenses, paint thickeners). In this thesis such systems are studied by means of a molecular dynamics/Monte Carlo simulation. At first, the system in rest is studied by means of graph theory. The changes in network topology upon cooling to the gel state, are characterized. Hereto an extensive study of the eigenvalue spectrum of the gel network is performed. As a result, an in-depth investigation of the eigenvalue spectra for spatial ER, scale-free, and small-world networks is carried out. Next, the gel under the application of a constant shear is studied, with a focus on shear banding and the changes in topology under shear. Finally, the relation between the gel transition and percolation is discussed.

  10. Functional Molecular Ecological Networks

    PubMed Central

    Zhou, Jizhong; Deng, Ye; Luo, Feng; He, Zhili; Tu, Qichao; Zhi, Xiaoyang

    2010-01-01

    Biodiversity and its responses to environmental changes are central issues in ecology and for society. Almost all microbial biodiversity research focuses on “species” richness and abundance but not on their interactions. Although a network approach is powerful in describing ecological interactions among species, defining the network structure in a microbial community is a great challenge. Also, although the stimulating effects of elevated CO2 (eCO2) on plant growth and primary productivity are well established, its influences on belowground microbial communities, especially microbial interactions, are poorly understood. Here, a random matrix theory (RMT)-based conceptual framework for identifying functional molecular ecological networks was developed with the high-throughput functional gene array hybridization data of soil microbial communities in a long-term grassland FACE (free air, CO2 enrichment) experiment. Our results indicate that RMT is powerful in identifying functional molecular ecological networks in microbial communities. Both functional molecular ecological networks under eCO2 and ambient CO2 (aCO2) possessed the general characteristics of complex systems such as scale free, small world, modular, and hierarchical. However, the topological structures of the functional molecular ecological networks are distinctly different between eCO2 and aCO2, at the levels of the entire communities, individual functional gene categories/groups, and functional genes/sequences, suggesting that eCO2 dramatically altered the network interactions among different microbial functional genes/populations. Such a shift in network structure is also significantly correlated with soil geochemical variables. In short, elucidating network interactions in microbial communities and their responses to environmental changes is fundamentally important for research in microbial ecology, systems microbiology, and global change. PMID:20941329

  11. Attractor Metabolic Networks

    PubMed Central

    De la Fuente, Ildefonso M.; Cortes, Jesus M.; Pelta, David A.; Veguillas, Juan

    2013-01-01

    Background The experimental observations and numerical studies with dissipative metabolic networks have shown that cellular enzymatic activity self-organizes spontaneously leading to the emergence of a Systemic Metabolic Structure in the cell, characterized by a set of different enzymatic reactions always locked into active states (metabolic core) while the rest of the catalytic processes are only intermittently active. This global metabolic structure was verified for Escherichia coli, Helicobacter pylori and Saccharomyces cerevisiae, and it seems to be a common key feature to all cellular organisms. In concordance with these observations, the cell can be considered a complex metabolic network which mainly integrates a large ensemble of self-organized multienzymatic complexes interconnected by substrate fluxes and regulatory signals, where multiple autonomous oscillatory and quasi-stationary catalytic patterns simultaneously emerge. The network adjusts the internal metabolic activities to the external change by means of flux plasticity and structural plasticity. Methodology/Principal Findings In order to research the systemic mechanisms involved in the regulation of the cellular enzymatic activity we have studied different catalytic activities of a dissipative metabolic network under different external stimuli. The emergent biochemical data have been analysed using statistical mechanic tools, studying some macroscopic properties such as the global information and the energy of the system. We have also obtained an equivalent Hopfield network using a Boltzmann machine. Our main result shows that the dissipative metabolic network can behave as an attractor metabolic network. Conclusions/Significance We have found that the systemic enzymatic activities are governed by attractors with capacity to store functional metabolic patterns which can be correctly recovered from specific input stimuli. The network attractors regulate the catalytic patterns, modify the efficiency

  12. Building new access network using reconfigurable optical grid network and wireless network

    NASA Astrophysics Data System (ADS)

    Qiu, Yinghui; Wu, Runze; Ji, Yuefeng; Xu, Daxiong

    2007-11-01

    Recently wireless mesh network has been gaining increasing attention and early versions are being deployed as municipal access solutions to eliminate the wired drop to every wireless router at customer premise. In this paper, we propose a novel access network using reconfigurable optical burst switching grid network and wireless mesh network. The proposed access network architecture saves network deployment cost because fiber need not penetrate to each end user. We also propose a hierarchical routing protocol to enhance the routing efficiency.

  13. BES Science Network Requirements

    SciTech Connect

    Biocca, Alan; Carlson, Rich; Chen, Jackie; Cotter, Steve; Tierney, Brian; Dattoria, Vince; Davenport, Jim; Gaenko, Alexander; Kent, Paul; Lamm, Monica; Miller, Stephen; Mundy, Chris; Ndousse, Thomas; Pederson, Mark; Perazzo, Amedeo; Popescu, Razvan; Rouson, Damian; Sekine, Yukiko; Sumpter, Bobby; Dart, Eli; Wang, Cai-Zhuang -Z; Whitelam, Steve; Zurawski, Jason

    2011-02-01

    The Energy Sciences Network (ESnet) is the primary provider of network connectivityfor the US Department of Energy Office of Science (SC), the single largest supporter of basic research in the physical sciences in the United States. In support of the Office ofScience programs, ESnet regularly updates and refreshes its understanding of the networking requirements of the instruments, facilities, scientists, and science programs that it serves. This focus has helped ESnet to be a highly successful enabler of scientific discovery for over 20 years.

  14. Advanced Optical Network

    NASA Astrophysics Data System (ADS)

    Braun, Steve; Michael, Xuejun

    The following article describes an advanced dense wavelength division multiplexing (DWDM) Optical Network developed by L-3 Photonics. The network, configured as an amplified optical bus, carries traffic simultaneously in both directions, using multiple wavelengths. As a result, data distribution is of the form peer-to-multi-peer, it is protocol independent, and it is scalable. The network leverages the rapid growth in commercial optical technologies, including wavelength division multiplexing (WDM), and when applied to military and commercial platforms such as aircraft, ships, unmanned and other vehicles, provides a cost-effective, low-weight, high-speed, and high noise-immune data distribution system.

  15. Broadband network selection issues

    NASA Astrophysics Data System (ADS)

    Leimer, Michael E.

    1996-01-01

    Selecting the best network for a given cable or telephone company provider is not as obvious as it appears. The cost and performance trades between Hybrid Fiber Coax (HFC), Fiber to the Curb (FTTC) and Asymmetric Digital Subscriber Line networks lead to very different choices based on the existing plant and the expected interactive subscriber usage model. This paper presents some of the issues and trades that drive network selection. The majority of the Interactive Television trials currently underway or planned are based on HFC networks. As a throw away market trial or a short term strategic incursion into a cable market, HFC may make sense. In the long run, if interactive services see high demand, HFC costs per node and an ever shrinking neighborhood node size to service large numbers of subscribers make FTTC appear attractive. For example, thirty-three 64-QAM modulators are required to fill the 550 MHz to 750 MHz spectrum with compressed video streams in 6 MHz channels. This large amount of hardware at each node drives not only initial build-out costs, but operations and maintenance costs as well. FTTC, with its potential for digitally switching large amounts of bandwidth to an given home, offers the potential to grow with the interactive subscriber base with less downstream cost. Integrated telephony on these networks is an issue that appears to be an afterthought for most of the networks being selected at the present time. The major players seem to be videocentric and include telephony as a simple add-on later. This may be a reasonable view point for the telephone companies that plan to leave their existing phone networks untouched. However, a phone company planning a network upgrade or a cable company jumping into the telephony business needs to carefully weigh the cost and performance issues of the various network choices. Each network type provides varying capability in both upstream and downstream bandwidth for voice channels. The noise characteristics

  16. NIRVANA network requirements

    SciTech Connect

    Wood, B.J.

    1990-08-01

    NIRVANA is an effort to standardize electrical computer-aided design workstations at Sandia National Laboratories in Albuquerque, New Mexico. The early effect of this project will be the introduction of at least 60 new engineering workstations at Sandia National Laboratories. Albuquerque, and at Allied Signal, Kansas City Division. These workstations are expected to begin arriving in September 1990. This paper proposes a design and outlines the requirements for a network to support the NIRVANA project. The author proposes a near-term network design, describes the security profile and caveats of this design, and proposes a long-term networking strategy for NIRVANA. 6 refs., 7 figs.

  17. Social Networks and Health.

    PubMed

    Perdiaris, Christos; Chardalias, Konstantinos; Magita, Andrianna; Mechili, Aggelos E; Diomidous, Marianna

    2015-01-01

    Nowadays the social networks have been developed into an advanced communications tool, which is important for all people to contact each other. These specific networks do offer lots of options as well as plenty of advantages and disadvantages. The social websites are many in number and titles, such as the facebook, the twitter, the bandoo etc. One of the most important function-mechanisms for the social network websites, are the marketing tools. The future goal is suggested to be the evolution of these programs. The development of these applications, which is going to lead into a new era for the social digital communication between the internet users, all around the globe.

  18. Modeling worldwide highway networks

    NASA Astrophysics Data System (ADS)

    Villas Boas, Paulino R.; Rodrigues, Francisco A.; da F. Costa, Luciano

    2009-12-01

    This Letter addresses the problem of modeling the highway systems of different countries by using complex networks formalism. More specifically, we compare two traditional geographical models with a modified geometrical network model where paths, rather than edges, are incorporated at each step between the origin and the destination vertices. Optimal configurations of parameters are obtained for each model and used for the comparison. The highway networks of Australia, Brazil, India, and Romania are considered and shown to be properly modeled by the modified geographical model.

  19. Learning In networks

    NASA Technical Reports Server (NTRS)

    Buntine, Wray L.

    1995-01-01

    Intelligent systems require software incorporating probabilistic reasoning, and often times learning. Networks provide a framework and methodology for creating this kind of software. This paper introduces network models based on chain graphs with deterministic nodes. Chain graphs are defined as a hierarchical combination of Bayesian and Markov networks. To model learning, plates on chain graphs are introduced to model independent samples. The paper concludes by discussing various operations that can be performed on chain graphs with plates as a simplification process or to generate learning algorithms.

  20. Multiuser quantum communication networks

    SciTech Connect

    Wojcik, Antoni; Kurzynski, Pawel; Grudka, Andrzej; Luczak, Tomasz; Gdala, Tomasz; Bednarska, Malgorzata

    2007-02-15

    We study a quantum state transfer between spins interacting with an arbitrary network of spins coupled by uniform XX interactions. It is shown that in such a system under fairly general conditions, we can expect a nearly perfect transfer of states. Then we analyze a generalization of this model to the case of many network users, where the sender can choose which party he wants to communicate with by appropriately tuning his local magnetic field. We also remark that a similar idea can be used to create an entanglement between several spins coupled to the network.

  1. Comparative analysis of collaboration networks

    SciTech Connect

    Progulova, Tatiana; Gadjiev, Bahruz

    2011-03-14

    In this paper we carry out a comparative analysis of the word network as the collaboration network based on the novel by M. Bulgakov 'Master and Margarita', the synonym network of the Russian language as well as the Russian movie actor network. We have constructed one-mode projections of these networks, defined degree distributions for them and have calculated main characteristics. In the paper a generation algorithm of collaboration networks has been offered which allows one to generate networks statistically equivalent to the studied ones. It lets us reveal a structural correlation between word network, synonym network and movie actor network. We show that the degree distributions of all analyzable networks are described by the distribution of q-type.

  2. Quantifying randomness in real networks

    NASA Astrophysics Data System (ADS)

    Orsini, Chiara; Dankulov, Marija M.; Colomer-de-Simón, Pol; Jamakovic, Almerima; Mahadevan, Priya; Vahdat, Amin; Bassler, Kevin E.; Toroczkai, Zoltán; Boguñá, Marián; Caldarelli, Guido; Fortunato, Santo; Krioukov, Dmitri

    2015-10-01

    Represented as graphs, real networks are intricate combinations of order and disorder. Fixing some of the structural properties of network models to their values observed in real networks, many other properties appear as statistical consequences of these fixed observables, plus randomness in other respects. Here we employ the dk-series, a complete set of basic characteristics of the network structure, to study the statistical dependencies between different network properties. We consider six real networks--the Internet, US airport network, human protein interactions, technosocial web of trust, English word network, and an fMRI map of the human brain--and find that many important local and global structural properties of these networks are closely reproduced by dk-random graphs whose degree distributions, degree correlations and clustering are as in the corresponding real network. We discuss important conceptual, methodological, and practical implications of this evaluation of network randomness, and release software to generate dk-random graphs.

  3. Quantifying randomness in real networks.

    PubMed

    Orsini, Chiara; Dankulov, Marija M; Colomer-de-Simón, Pol; Jamakovic, Almerima; Mahadevan, Priya; Vahdat, Amin; Bassler, Kevin E; Toroczkai, Zoltán; Boguñá, Marián; Caldarelli, Guido; Fortunato, Santo; Krioukov, Dmitri

    2015-10-20

    Represented as graphs, real networks are intricate combinations of order and disorder. Fixing some of the structural properties of network models to their values observed in real networks, many other properties appear as statistical consequences of these fixed observables, plus randomness in other respects. Here we employ the dk-series, a complete set of basic characteristics of the network structure, to study the statistical dependencies between different network properties. We consider six real networks--the Internet, US airport network, human protein interactions, technosocial web of trust, English word network, and an fMRI map of the human brain--and find that many important local and global structural properties of these networks are closely reproduced by dk-random graphs whose degree distributions, degree correlations and clustering are as in the corresponding real network. We discuss important conceptual, methodological, and practical implications of this evaluation of network randomness, and release software to generate dk-random graphs.

  4. Effects of network structure and routing strategy on network capacity

    NASA Astrophysics Data System (ADS)

    Chen, Zhen Yi; Wang, Xiao Fan

    2006-03-01

    The capacity of maximum end-to-end traffic flow the network is able to handle without overloading is an important index for network performance in real communication systems. In this paper, we estimate the variations of network capacity under different routing strategies for three different topologies. Simulation results reveal that the capacity depends on the underlying network structure and the capacity increases as the network becomes more homogeneous. It is also observed that the network capacity is greatly enhanced when the new traffic awareness routing strategy is adopted in each network structure.

  5. Divers Alert Network

    MedlinePlus

    ... Network, the diving industry’s largest association dedicated to scuba diving safety. Serving scuba divers for more than 30 ... to help cover the cost of treatment for scuba diving injuries. DAN fulfilled that need by developing diving’s ...

  6. Autocatalysis in reaction networks.

    PubMed

    Deshpande, Abhishek; Gopalkrishnan, Manoj

    2014-10-01

    The persistence conjecture is a long-standing open problem in chemical reaction network theory. It concerns the behavior of solutions to coupled ODE systems that arise from applying mass-action kinetics to a network of chemical reactions. The idea is that if all reactions are reversible in a weak sense, then no species can go extinct. A notion that has been found useful in thinking about persistence is that of "critical siphon." We explore the combinatorics of critical siphons, with a view toward the persistence conjecture. We introduce the notions of "drainable" and "self-replicable" (or autocatalytic) siphons. We show that: Every minimal critical siphon is either drainable or self-replicable; reaction networks without drainable siphons are persistent; and nonautocatalytic weakly reversible networks are persistent. Our results clarify that the difficulties in proving the persistence conjecture are essentially due to competition between drainable and self-replicable siphons. PMID:25245394

  7. Multitasking associative networks.

    PubMed

    Agliari, Elena; Barra, Adriano; Galluzzi, Andrea; Guerra, Francesco; Moauro, Francesco

    2012-12-28

    We introduce a bipartite, diluted and frustrated, network as a sparse restricted Boltzmann machine and we show its thermodynamical equivalence to an associative working memory able to retrieve several patterns in parallel without falling into spurious states typical of classical neural networks. We focus on systems processing in parallel a finite (up to logarithmic growth in the volume) amount of patterns, mirroring the low-level storage of standard Amit-Gutfreund-Sompolinsky theory. Results obtained through statistical mechanics, the signal-to-noise technique, and Monte Carlo simulations are overall in perfect agreement and carry interesting biological insights. Indeed, these associative networks pave new perspectives in the understanding of multitasking features expressed by complex systems, e.g., neural and immune networks.

  8. Network science: Destruction perfected

    NASA Astrophysics Data System (ADS)

    Kovács, István A.; Barabási, Albert-László

    2015-08-01

    Pinpointing the nodes whose removal most effectively disrupts a network has become a lot easier with the development of an efficient algorithm. Potential applications might include cybersecurity and disease control. See Letter p.65

  9. Autocatalysis in reaction networks.

    PubMed

    Deshpande, Abhishek; Gopalkrishnan, Manoj

    2014-10-01

    The persistence conjecture is a long-standing open problem in chemical reaction network theory. It concerns the behavior of solutions to coupled ODE systems that arise from applying mass-action kinetics to a network of chemical reactions. The idea is that if all reactions are reversible in a weak sense, then no species can go extinct. A notion that has been found useful in thinking about persistence is that of "critical siphon." We explore the combinatorics of critical siphons, with a view toward the persistence conjecture. We introduce the notions of "drainable" and "self-replicable" (or autocatalytic) siphons. We show that: Every minimal critical siphon is either drainable or self-replicable; reaction networks without drainable siphons are persistent; and nonautocatalytic weakly reversible networks are persistent. Our results clarify that the difficulties in proving the persistence conjecture are essentially due to competition between drainable and self-replicable siphons.

  10. Compressively sensed complex networks.

    SciTech Connect

    Dunlavy, Daniel M.; Ray, Jaideep; Pinar, Ali

    2010-07-01

    The aim of this project is to develop low dimension parametric (deterministic) models of complex networks, to use compressive sensing (CS) and multiscale analysis to do so and to exploit the structure of complex networks (some are self-similar under coarsening). CS provides a new way of sampling and reconstructing networks. The approach is based on multiresolution decomposition of the adjacency matrix and its efficient sampling. It requires preprocessing of the adjacency matrix to make it 'blocky' which is the biggest (combinatorial) algorithm challenge. Current CS reconstruction algorithm makes no use of the structure of a graph, its very general (and so not very efficient/customized). Other model-based CS techniques exist, but not yet adapted to networks. Obvious starting point for future work is to increase the efficiency of reconstruction.

  11. The Deep Space Network

    NASA Technical Reports Server (NTRS)

    1977-01-01

    The various systems and subsystems are discussed for the Deep Space Network (DSN). A description of the DSN is presented along with mission support, program planning, facility engineering, implementation and operations.

  12. NP Science Network Requirements

    SciTech Connect

    Dart, Eli; Rotman, Lauren; Tierney, Brian

    2011-08-26

    The Energy Sciences Network (ESnet) is the primary provider of network connectivity for the U.S. Department of Energy (DOE) Office of Science (SC), the single largest supporter of basic research in the physical sciences in the United States. To support SC programs, ESnet regularly updates and refreshes its understanding of the networking requirements of the instruments, facilities, scientists, and science programs it serves. This focus has helped ESnet to be a highly successful enabler of scientific discovery for over 20 years. In August 2011, ESnet and the Office of Nuclear Physics (NP), of the DOE SC, organized a workshop to characterize the networking requirements of the programs funded by NP. The requirements identified at the workshop are summarized in the Findings section, and are described in more detail in the body of the report.

  13. Networks Around the World.

    ERIC Educational Resources Information Center

    Online & CD-ROM Review, 1997

    1997-01-01

    Examines the topic of networked information. Discusses the possibility of a global stock exchange, the utility of environmental information on the Internet, the Internet in India, and Internet user types and habits according to a survey conducted in Denmark. (AEF)

  14. ESNET (Energy Sciences Network)

    SciTech Connect

    Not Available

    1987-06-01

    This document describes the Energy Sciences Network (ESNET) project which was undertaken by the Scientific Computing Staff during fiscal year (FY) 1986 at the direction of the Director, Office of Energy Research (ER). This document serves as the program plan for the ESNET project and is the result of the effort of the cross program Energy Sciences Network Steering Committee. The ESNET Steering Committee has been charged to codify the overall ER computer network requirements, to document and set priorities for computer networking requirements including performance objectives. Further, this committee has been asked to identify future ESNET functional characteristics, to identify research and development needs for the ESNET, to establish ESNET performance objectives and to define the intrastructure necessary to manage and operate the ESNET facilities.

  15. Multitasking Associative Networks

    NASA Astrophysics Data System (ADS)

    Agliari, Elena; Barra, Adriano; Galluzzi, Andrea; Guerra, Francesco; Moauro, Francesco

    2012-12-01

    We introduce a bipartite, diluted and frustrated, network as a sparse restricted Boltzmann machine and we show its thermodynamical equivalence to an associative working memory able to retrieve several patterns in parallel without falling into spurious states typical of classical neural networks. We focus on systems processing in parallel a finite (up to logarithmic growth in the volume) amount of patterns, mirroring the low-level storage of standard Amit-Gutfreund-Sompolinsky theory. Results obtained through statistical mechanics, the signal-to-noise technique, and Monte Carlo simulations are overall in perfect agreement and carry interesting biological insights. Indeed, these associative networks pave new perspectives in the understanding of multitasking features expressed by complex systems, e.g., neural and immune networks.

  16. Computers, Networks and Work.

    ERIC Educational Resources Information Center

    Sproull, Lee; Kiesler, Sara

    1991-01-01

    Discussed are how computer networks can affect the nature of work and the relationships between managers and employees. The differences between face-to-face exchanges and electronic interactions are described. (KR)

  17. The network takeover

    NASA Astrophysics Data System (ADS)

    Barabási, Albert-László

    2012-01-01

    Reductionism, as a paradigm, is expired, and complexity, as a field, is tired. Data-based mathematical models of complex systems are offering a fresh perspective, rapidly developing into a new discipline: network science.

  18. Netiquettes for Networkers.

    ERIC Educational Resources Information Center

    McMurdo, George

    1995-01-01

    Presents 20 networking etiquette guidelines taken from electronic and print sources. Highlights include focusing on one subject, condensing messages, editing quotes, spelling and grammar, typography, mistakes, acronyms, humor, researching discussion groups, intellectual property and copyright, manners, ethics, and damage. (AEF)

  19. Integrated Networks Branch

    Cancer.gov

    INB supports the National Outreach Network, the Geographic Management of Cancer Health Disparities Program, and advises on women’s health and sexual and gender minority opportunities within and across NCI.

  20. Collaborative Electronic Network Building.

    ERIC Educational Resources Information Center

    DiMauro, Vanessa; Jacobs, Gloria

    1995-01-01

    Addresses research questions related to purposeful collaboration as a mechanism for successful teacher professional development in the process of designing a telecommunications network with users. (19 references) (Author/MKR)

  1. The Deep Space Network

    NASA Technical Reports Server (NTRS)

    1979-01-01

    Progress on the Deep Space Network (DSN) supporting research and technology, advanced development, engineering and implementation, and DSN operations is presented. The functions and facilities of the DSN are described.

  2. Evolution of document networks.

    PubMed

    Menczer, Filippo

    2004-04-01

    How does a network of documents grow without centralized control? This question is becoming crucial as we try to explain the emergent scale-free topology of the World Wide Web and use link analysis to identify important information resources. Existing models of growing information networks have focused on the structure of links but neglected the content of nodes. Here I show that the current models fail to reproduce a critical characteristic of information networks, namely the distribution of textual similarity among linked documents. I propose a more realistic model that generates links by using both popularity and content. This model yields remarkably accurate predictions of both degree and similarity distributions in networks of web pages and scientific literature.

  3. LINCS: Livermore's network architecture. [Octopus computing network

    SciTech Connect

    Fletcher, J.G.

    1982-01-01

    Octopus, a local computing network that has been evolving at the Lawrence Livermore National Laboratory for over fifteen years, is currently undergoing a major revision. The primary purpose of the revision is to consolidate and redefine the variety of conventions and formats, which have grown up over the years, into a single standard family of protocols, the Livermore Interactive Network Communication Standard (LINCS). This standard treats the entire network as a single distributed operating system such that access to a computing resource is obtained in a single way, whether that resource is local (on the same computer as the accessing process) or remote (on another computer). LINCS encompasses not only communication but also such issues as the relationship of customer to server processes and the structure, naming, and protection of resources. The discussion includes: an overview of the Livermore user community and computing hardware, the functions and structure of each of the seven layers of LINCS protocol, the reasons why we have designed our own protocols and why we are dissatisfied by the directions that current protocol standards are taking.

  4. The Colombia Seismological Network

    NASA Astrophysics Data System (ADS)

    Blanco Chia, J. F.; Poveda, E.; Pedraza, P.

    2013-05-01

    The latest seismological equipment and data processing instrumentation installed at the Colombia Seismological Network (RSNC) are described. System configuration, network operation, and data management are discussed. The data quality and the new seismological products are analyzed. The main purpose of the network is to monitor local seismicity with a special emphasis on seismic activity surrounding the Colombian Pacific and Caribbean oceans, for early warning in case a Tsunami is produced by an earthquake. The Colombian territory is located at the South America northwestern corner, here three tectonic plates converge: Nazca, Caribbean and the South American. The dynamics of these plates, when resulting in earthquakes, is continuously monitored by the network. In 2012, the RSNC registered in 2012 an average of 67 events per day; from this number, a mean of 36 earthquakes were possible to be located well. In 2010 the network was also able to register an average of 67 events, but it was only possible to locate a mean of 28 earthquakes daily. This difference is due to the expansion of the network. The network is made up of 84 stations equipped with different kind of broadband 40s, 120s seismometers, accelerometers and short period 1s sensors. The signal is transmitted continuously in real-time to the Central Recording Center located at Bogotá, using satellite, telemetry, and Internet. Moreover, there are some other stations which are required to collect the information in situ. Data is recorded and processed digitally using two different systems, EARTHWORM and SEISAN, which are able to process and share the information between them. The RSNC has designed and implemented a web system to share the seismological data. This innovative system uses tools like Java Script, Oracle and programming languages like PHP to allow the users to access the seismicity registered by the network almost in real time as well as to download the waveform and technical details. The coverage

  5. Homogeneous complex networks

    NASA Astrophysics Data System (ADS)

    Bogacz, Leszek; Burda, Zdzisław; Wacław, Bartłomiej

    2006-07-01

    We discuss various ensembles of homogeneous complex networks and a Monte-Carlo method of generating graphs from these ensembles. The method is quite general and can be applied to simulate micro-canonical, canonical or grand-canonical ensembles for systems with various statistical weights. It can be used to construct homogeneous networks with desired properties, or to construct a non-trivial scoring function for problems of advanced motif searching.

  6. Fixed Access Network Sharing

    NASA Astrophysics Data System (ADS)

    Cornaglia, Bruno; Young, Gavin; Marchetta, Antonio

    2015-12-01

    Fixed broadband network deployments are moving inexorably to the use of Next Generation Access (NGA) technologies and architectures. These NGA deployments involve building fiber infrastructure increasingly closer to the customer in order to increase the proportion of fiber on the customer's access connection (Fibre-To-The-Home/Building/Door/Cabinet… i.e. FTTx). This increases the speed of services that can be sold and will be increasingly required to meet the demands of new generations of video services as we evolve from HDTV to "Ultra-HD TV" with 4k and 8k lines of video resolution. However, building fiber access networks is a costly endeavor. It requires significant capital in order to cover any significant geographic coverage. Hence many companies are forming partnerships and joint-ventures in order to share the NGA network construction costs. One form of such a partnership involves two companies agreeing to each build to cover a certain geographic area and then "cross-selling" NGA products to each other in order to access customers within their partner's footprint (NGA coverage area). This is tantamount to a bi-lateral wholesale partnership. The concept of Fixed Access Network Sharing (FANS) is to address the possibility of sharing infrastructure with a high degree of flexibility for all network operators involved. By providing greater configuration control over the NGA network infrastructure, the service provider has a greater ability to define the network and hence to define their product capabilities at the active layer. This gives the service provider partners greater product development autonomy plus the ability to differentiate from each other at the active network layer.

  7. VOIP over Space Networks

    NASA Technical Reports Server (NTRS)

    Okino, C.; Kwong, W.; Pang, Jackson; Gao, Jerry; Clare, L.

    2006-01-01

    This viewgraph presentation reviews Voice over Internet Protocol (VOIP) over a space networking environment. The topics include: 1) Drivers for VOIP in Space; 2) Challenges in the Space Networking Environment: Long Latencies, Path errors, Simplex paths, Asymmetric paths, QoS requirements, Team-based operations, and Overhead concerns; 3) Possible VOIPOSN approaches; 4) Study of BER, code type and voice frame length on PESQ-MOS; 5) Codec Latency Trade Space; and 6) Testbed.

  8. OPTIMAL NETWORK TOPOLOGY DESIGN

    NASA Technical Reports Server (NTRS)

    Yuen, J. H.

    1994-01-01

    This program was developed as part of a research study on the topology design and performance analysis for the Space Station Information System (SSIS) network. It uses an efficient algorithm to generate candidate network designs (consisting of subsets of the set of all network components) in increasing order of their total costs, and checks each design to see if it forms an acceptable network. This technique gives the true cost-optimal network, and is particularly useful when the network has many constraints and not too many components. It is intended that this new design technique consider all important performance measures explicitly and take into account the constraints due to various technical feasibilities. In the current program, technical constraints are taken care of by the user properly forming the starting set of candidate components (e.g. nonfeasible links are not included). As subsets are generated, they are tested to see if they form an acceptable network by checking that all requirements are satisfied. Thus the first acceptable subset encountered gives the cost-optimal topology satisfying all given constraints. The user must sort the set of "feasible" link elements in increasing order of their costs. The program prompts the user for the following information for each link: 1) cost, 2) connectivity (number of stations connected by the link), and 3) the stations connected by that link. Unless instructed to stop, the program generates all possible acceptable networks in increasing order of their total costs. The program is written only to generate topologies that are simply connected. Tests on reliability, delay, and other performance measures are discussed in the documentation, but have not been incorporated into the program. This program is written in PASCAL for interactive execution and has been implemented on an IBM PC series computer operating under PC DOS. The disk contains source code only. This program was developed in 1985.

  9. Nanostructured cellular networks.

    PubMed

    Moriarty, P; Taylor, M D R; Brust, M

    2002-12-01

    Au nanocrystals spin-coated onto silicon from toluene form cellular networks. A quantitative statistical crystallography analysis shows that intercellular correlations drive the networks far from statistical equilibrium. Spin-coating from hexane does not produce cellular structure, yet a strong correlation is retained in the positions of nanocrystal aggregates. Mechanisms based on Marangoni convection alone cannot account for the variety of patterns observed, and we argue that spinodal decomposition plays an important role in foam formation.

  10. Electronic Neural Networks

    NASA Technical Reports Server (NTRS)

    Lambe, John; Moopen, Alexander; Thakoor, Anilkumar P.

    1988-01-01

    Memory based on neural network models content-addressable and fault-tolerant. System includes electronic equivalent of synaptic network; particular, matrix of programmable binary switching elements over which data distributed. Switches programmed in parallel by outputs of serial-input/parallel-output shift registers. Input and output terminals of bank of high-gain nonlinear amplifiers connected in nonlinear-feedback configuration by switches and by memory-prompting shift registers.

  11. High performance satellite networks

    NASA Astrophysics Data System (ADS)

    Helm, Neil R.; Edelson, Burton I.

    1997-06-01

    The high performance satellite communications networks of the future will have to be interoperable with terrestrial fiber cables. These satellite networks will evolve from narrowband analogue formats to broadband digital transmission schemes, with protocols, algorithms and transmission architectures that will segment the data into uniform cells and frames, and then transmit these data via larger and more efficient synchronous optional (SONET) and asynchronous transfer mode (ATM) networks that are being developed for the information "superhighway". These high performance satellite communications and information networks are required for modern applications, such as electronic commerce, digital libraries, medical imaging, distance learning, and the distribution of science data. In order for satellites to participate in these information superhighway networks, it is essential that they demonstrate their ability to: (1) operate seamlessly with heterogeneous architectures and applications, (2) carry data at SONET rates with the same quality of service as optical fibers, (3) qualify transmission delay as a parameter not a problem, and (4) show that satellites have several performance and economic advantages over fiber cable networks.

  12. Coupled biopolymer networks

    NASA Astrophysics Data System (ADS)

    Schwarz, J. M.; Zhang, Tao

    2015-03-01

    The actin cytoskeleton provides the cell with structural integrity and allows it to change shape to crawl along a surface, for example. The actin cytoskeleton can be modeled as a semiflexible biopolymer network that modifies its morphology in response to both external and internal stimuli. Just inside the inner nuclear membrane of a cell exists a network of filamentous lamin that presumably protects the heart of the cell nucleus--the DNA. Lamins are intermediate filaments that can also be modeled as semiflexible biopolymers. It turns out that the actin cytoskeletal biopolymer network and the lamin biopolymer network are coupled via a sequence of proteins that bridge the outer and inner nuclear membranes. We, therefore, probe the consequences of such a coupling via numerical simulations to understand the resulting deformations in the lamin network in response to perturbations in the cytoskeletal network. Such study could have implications for mechanical mechanisms of the regulation of transcription, since DNA--yet another semiflexible polymer--contains lamin-binding domains, and, thus, widen the field of epigenetics.

  13. Scaling in Transportation Networks

    PubMed Central

    Louf, Rémi; Roth, Camille; Barthelemy, Marc

    2014-01-01

    Subway systems span most large cities, and railway networks most countries in the world. These networks are fundamental in the development of countries and their cities, and it is therefore crucial to understand their formation and evolution. However, if the topological properties of these networks are fairly well understood, how they relate to population and socio-economical properties remains an open question. We propose here a general coarse-grained approach, based on a cost-benefit analysis that accounts for the scaling properties of the main quantities characterizing these systems (the number of stations, the total length, and the ridership) with the substrate's population, area and wealth. More precisely, we show that the length, number of stations and ridership of subways and rail networks can be estimated knowing the area, population and wealth of the underlying region. These predictions are in good agreement with data gathered for about subway systems and more than railway networks in the world. We also show that train networks and subway systems can be described within the same framework, but with a fundamental difference: while the interstation distance seems to be constant and determined by the typical walking distance for subways, the interstation distance for railways scales with the number of stations. PMID:25029528

  14. 78 FR 775 - Goodman Networks, Inc. Core Network Engineering (Deployment Engineering) Division Alpharetta, GA...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-01-04

    ... Employment and Training Administration Goodman Networks, Inc. Core Network Engineering (Deployment Engineering) Division Alpharetta, GA; Goodman Networks, Inc. Core Network Engineering (Deployment Engineering) Division Hunt Valley, MD; Goodman Networks, Inc. Core Network Engineering (Deployment Engineering)...

  15. Neural Network Development Tool (NETS)

    NASA Technical Reports Server (NTRS)

    Baffes, Paul T.

    1990-01-01

    Artificial neural networks formed from hundreds or thousands of simulated neurons, connected in manner similar to that in human brain. Such network models learning behavior. Using NETS involves translating problem to be solved into input/output pairs, designing network configuration, and training network. Written in C.

  16. Campus Networking Strategies: An Introduction.

    ERIC Educational Resources Information Center

    Roberts, Michael M.

    1988-01-01

    This article is adapted from the introduction to EDUCOM's forthcoming book, Campus Networking Strategies, which includes 10 case study chapters detailing academic experiences with computer networking. Topics discussed in the introduction include network issues for management, networking economics, engineering and telecommunications issues, and…

  17. Network Leadership: An Emerging Practice

    ERIC Educational Resources Information Center

    Tremblay, Christopher W.

    2012-01-01

    Network leadership is an emerging approach that can have an impact on change in education and in society. According to Merriam-Webster (2011), a network is "an interconnected or interrelated chain, group, or system." Intentional interconnectedness is what separates network leadership from other leadership theories. Network leadership has the…

  18. From network structure to network reorganization: implications for adult neurogenesis

    NASA Astrophysics Data System (ADS)

    Schneider-Mizell, Casey M.; Parent, Jack M.; Ben-Jacob, Eshel; Zochowski, Michal R.; Sander, Leonard M.

    2010-12-01

    Networks can be dynamical systems that undergo functional and structural reorganization. One example of such a process is adult hippocampal neurogenesis, in which new cells are continuously born and incorporate into the existing network of the dentate gyrus region of the hippocampus. Many of these introduced cells mature and become indistinguishable from established neurons, joining the existing network. Activity in the network environment is known to promote birth, survival and incorporation of new cells. However, after epileptogenic injury, changes to the connectivity structure around the neurogenic niche are known to correlate with aberrant neurogenesis. The possible role of network-level changes in the development of epilepsy is not well understood. In this paper, we use a computational model to investigate how the structural and functional outcomes of network reorganization, driven by addition of new cells during neurogenesis, depend on the original network structure. We find that there is a stable network topology that allows the network to incorporate new neurons in a manner that enhances activity of the persistently active region, but maintains global network properties. In networks having other connectivity structures, new cells can greatly alter the distribution of firing activity and destroy the initial activity patterns. We thus find that new cells are able to provide focused enhancement of network only for small-world networks with sufficient inhibition. Network-level deviations from this topology, such as those caused by epileptogenic injury, can set the network down a path that develops toward pathological dynamics and aberrant structural integration of new cells.

  19. Program Helps Simulate Neural Networks

    NASA Technical Reports Server (NTRS)

    Villarreal, James; Mcintire, Gary

    1993-01-01

    Neural Network Environment on Transputer System (NNETS) computer program provides users high degree of flexibility in creating and manipulating wide variety of neural-network topologies at processing speeds not found in conventional computing environments. Supports back-propagation and back-propagation-related algorithms. Back-propagation algorithm used is implementation of Rumelhart's generalized delta rule. NNETS developed on INMOS Transputer(R). Predefines back-propagation network, Jordan network, and reinforcement network to assist users in learning and defining own networks. Also enables users to configure other neural-network paradigms from NNETS basic architecture. Small portion of software written in OCCAM(R) language.

  20. Statistical mechanics of complex networks

    NASA Astrophysics Data System (ADS)

    Albert, Réka; Barabási, Albert-László

    2002-01-01

    Complex networks describe a wide range of systems in nature and society. Frequently cited examples include the cell, a network of chemicals linked by chemical reactions, and the Internet, a network of routers and computers connected by physical links. While traditionally these systems have been modeled as random graphs, it is increasingly recognized that the topology and evolution of real networks are governed by robust organizing principles. This article reviews the recent advances in the field of complex networks, focusing on the statistical mechanics of network topology and dynamics. After reviewing the empirical data that motivated the recent interest in networks, the authors discuss the main models and analytical tools, covering random graphs, small-world and scale-free networks, the emerging theory of evolving networks, and the interplay between topology and the network's robustness against failures and attacks.

  1. Quantifying randomness in real networks

    PubMed Central

    Orsini, Chiara; Dankulov, Marija M.; Colomer-de-Simón, Pol; Jamakovic, Almerima; Mahadevan, Priya; Vahdat, Amin; Bassler, Kevin E.; Toroczkai, Zoltán; Boguñá, Marián; Caldarelli, Guido; Fortunato, Santo; Krioukov, Dmitri

    2015-01-01

    Represented as graphs, real networks are intricate combinations of order and disorder. Fixing some of the structural properties of network models to their values observed in real networks, many other properties appear as statistical consequences of these fixed observables, plus randomness in other respects. Here we employ the dk-series, a complete set of basic characteristics of the network structure, to study the statistical dependencies between different network properties. We consider six real networks—the Internet, US airport network, human protein interactions, technosocial web of trust, English word network, and an fMRI map of the human brain—and find that many important local and global structural properties of these networks are closely reproduced by dk-random graphs whose degree distributions, degree correlations and clustering are as in the corresponding real network. We discuss important conceptual, methodological, and practical implications of this evaluation of network randomness, and release software to generate dk-random graphs. PMID:26482121

  2. Computing preimages of Boolean networks.

    PubMed

    Klotz, Johannes; Bossert, Martin; Schober, Steffen

    2013-01-01

    In this paper we present an algorithm based on the sum-product algorithm that finds elements in the preimage of a feed-forward Boolean networks given an output of the network. Our probabilistic method runs in linear time with respect to the number of nodes in the network. We evaluate our algorithm for randomly constructed Boolean networks and a regulatory network of Escherichia coli and found that it gives a valid solution in most cases. PMID:24267277

  3. Computer and information networks.

    PubMed

    Greenberger, M; Aronofsky, J; McKenney, J L; Massy, W F

    1973-10-01

    The most basic conclusion coming out of the EDUCOM seminars is that computer networking must be acknowledged as an important new mode for obtaining information and computation (15). It is a real alternative that needs to be given serious attention in current planning and decision-making. Yet the fact is that many institutions are not taking account of networks when they confer on whether or how to replace their main computer. Articulation of the possibilities of computer networks goes back to the early 1960's and before, and working networks have been in evidence for several years now, both commercially and in universities. What is new, however, is the unmistakable recognition-bordering on a sense of the inevitable-that networks are finally practical and here to stay. The visionary and promotional phases of computer networks are over. It is time for hard-nosed comparative analysis (16). Another conclusion of the seminars has to do with the factors that hinder the fuller development of networking. The major problems to be overcome in applying networks to research and education are political, organizational, and economic in nature rather than technological. This is not to say that the hardware and software problems of linking computers and information systems are completely solved, but they are not the big bottlenecks at present. Research and educational institutions must find ways to organize themselves as well as their computers to work together for greater resource sharing. The coming of age of networks takes on special significance as a result of widespread dissatisfactions expressed with the present computing situation. There is a feeling that the current mode of autonomous, self-sufficient operation in the provision of computing and information services is frequently wasteful, deficient, and unresponsive to users' needs because of duplication of effort from one installation to another, incompatibilities, and inadequate documentation, program support, and user

  4. Computer and information networks.

    PubMed

    Greenberger, M; Aronofsky, J; McKenney, J L; Massy, W F

    1973-10-01

    The most basic conclusion coming out of the EDUCOM seminars is that computer networking must be acknowledged as an important new mode for obtaining information and computation (15). It is a real alternative that needs to be given serious attention in current planning and decision-making. Yet the fact is that many institutions are not taking account of networks when they confer on whether or how to replace their main computer. Articulation of the possibilities of computer networks goes back to the early 1960's and before, and working networks have been in evidence for several years now, both commercially and in universities. What is new, however, is the unmistakable recognition-bordering on a sense of the inevitable-that networks are finally practical and here to stay. The visionary and promotional phases of computer networks are over. It is time for hard-nosed comparative analysis (16). Another conclusion of the seminars has to do with the factors that hinder the fuller development of networking. The major problems to be overcome in applying networks to research and education are political, organizational, and economic in nature rather than technological. This is not to say that the hardware and software problems of linking computers and information systems are completely solved, but they are not the big bottlenecks at present. Research and educational institutions must find ways to organize themselves as well as their computers to work together for greater resource sharing. The coming of age of networks takes on special significance as a result of widespread dissatisfactions expressed with the present computing situation. There is a feeling that the current mode of autonomous, self-sufficient operation in the provision of computing and information services is frequently wasteful, deficient, and unresponsive to users' needs because of duplication of effort from one installation to another, incompatibilities, and inadequate documentation, program support, and user

  5. Mobile infostation network technology

    NASA Astrophysics Data System (ADS)

    Rajappan, Gowri; Acharya, Joydeep; Liu, Hongbo; Mandayam, Narayan; Seskar, Ivan; Yates, Roy

    2006-05-01

    Inefficient use of network resources on the battlefield is a serious liability: if an asset communicates with the network command for data-a terrain map, for instance-it ties up the end-to-end network resources. When many such assets contend for data simultaneously, traffic is limited by the slowest link along the path from the network command to the asset. A better approach is for a local server, known as an infostation, to download data on an anticipated-need basis when the network load is low. The infostation can then dump data when needed to the assets over a high-speed wireless connection. The infostation serves the local assets over an OFDM-based wireless data link that has MIMO enhancements for high data rate and robustness. We aim for data rate in excess of 100 Mbps, spectral efficiency in excess of 5 bits/sec/Hz, and robustness to poor channel conditions and jammers. We propose an adaptive physical layer that determines power levels, modulation schemes, and the MIMO enhancements to use based on the channel state and the level of interference in the system. We also incorporate the idea of superuser: a user who is allowed preferential use of the high data rate link. We propose a MAC that allows for this priority-based bandwidth allocation scheme. The proposed infostation MAC is integrated tightly with the physical layer through a cross-layer design. We call the proposed infostation PHY, MAC, and network technology, collectively, as the Mobile Infostation Network Technology (MINT).

  6. Network motifs: simple building blocks of complex networks.

    PubMed

    Milo, R; Shen-Orr, S; Itzkovitz, S; Kashtan, N; Chklovskii, D; Alon, U

    2002-10-25

    Complex networks are studied across many fields of science. To uncover their structural design principles, we defined "network motifs," patterns of interconnections occurring in complex networks at numbers that are significantly higher than those in randomized networks. We found such motifs in networks from biochemistry, neurobiology, ecology, and engineering. The motifs shared by ecological food webs were distinct from the motifs shared by the genetic networks of Escherichia coli and Saccharomyces cerevisiae or from those found in the World Wide Web. Similar motifs were found in networks that perform information processing, even though they describe elements as different as biomolecules within a cell and synaptic connections between neurons in Caenorhabditis elegans. Motifs may thus define universal classes of networks. This approach may uncover the basic building blocks of most networks. PMID:12399590

  7. Fluvial network organization imprints on microbial co-occurrence networks

    PubMed Central

    Widder, Stefanie; Besemer, Katharina; Singer, Gabriel A.; Ceola, Serena; Bertuzzo, Enrico; Quince, Christopher; Sloan, William T.; Rinaldo, Andrea; Battin, Tom J.

    2014-01-01

    Recent studies highlight linkages among the architecture of ecological networks, their persistence facing environmental disturbance, and the related patterns of biodiversity. A hitherto unresolved question is whether the structure of the landscape inhabited by organisms leaves an imprint on their ecological networks. We analyzed, based on pyrosequencing profiling of the biofilm communities in 114 streams, how features inherent to fluvial networks affect the co-occurrence networks that the microorganisms form in these biofilms. Our findings suggest that hydrology and metacommunity dynamics, both changing predictably across fluvial networks, affect the fragmentation of the microbial co-occurrence networks throughout the fluvial network. The loss of taxa from co-occurrence networks demonstrates that the removal of gatekeepers disproportionately contributed to network fragmentation, which has potential implications for the functions biofilms fulfill in stream ecosystems. Our findings are critical because of increased anthropogenic pressures deteriorating stream ecosystem integrity and biodiversity. PMID:25136087

  8. Network Motifs: Simple Building Blocks of Complex Networks

    NASA Astrophysics Data System (ADS)

    Milo, R.; Shen-Orr, S.; Itzkovitz, S.; Kashtan, N.; Chklovskii, D.; Alon, U.

    2002-10-01

    Complex networks are studied across many fields of science. To uncover their structural design principles, we defined ``network motifs,'' patterns of interconnections occurring in complex networks at numbers that are significantly higher than those in randomized networks. We found such motifs in networks from biochemistry, neurobiology, ecology, and engineering. The motifs shared by ecological food webs were distinct from the motifs shared by the genetic networks of Escherichia coli and Saccharomyces cerevisiae or from those found in the World Wide Web. Similar motifs were found in networks that perform information processing, even though they describe elements as different as biomolecules within a cell and synaptic connections between neurons in Caenorhabditis elegans. Motifs may thus define universal classes of networks. This approach may uncover the basic building blocks of most networks.

  9. Fluvial network organization imprints on microbial co-occurrence networks.

    PubMed

    Widder, Stefanie; Besemer, Katharina; Singer, Gabriel A; Ceola, Serena; Bertuzzo, Enrico; Quince, Christopher; Sloan, William T; Rinaldo, Andrea; Battin, Tom J

    2014-09-01

    Recent studies highlight linkages among the architecture of ecological networks, their persistence facing environmental disturbance, and the related patterns of biodiversity. A hitherto unresolved question is whether the structure of the landscape inhabited by organisms leaves an imprint on their ecological networks. We analyzed, based on pyrosequencing profiling of the biofilm communities in 114 streams, how features inherent to fluvial networks affect the co-occurrence networks that the microorganisms form in these biofilms. Our findings suggest that hydrology and metacommunity dynamics, both changing predictably across fluvial networks, affect the fragmentation of the microbial co-occurrence networks throughout the fluvial network. The loss of taxa from co-occurrence networks demonstrates that the removal of gatekeepers disproportionately contributed to network fragmentation, which has potential implications for the functions biofilms fulfill in stream ecosystems. Our findings are critical because of increased anthropogenic pressures deteriorating stream ecosystem integrity and biodiversity. PMID:25136087

  10. Distinction and connection between contact network, social network, and disease transmission network.

    PubMed

    Chen, Shi; Lanzas, Cristina

    2016-09-01

    In this paper we discuss the distinction and connection between three closely related networks in animal ecology and epidemiology studies: the contact, social, and disease transmission networks. We provide a robust theoretical definition and interpretation of these three networks, demonstrate that social and disease transmission networks can be derived as spanning subgraphs of contact network, and show examples based on real-world high-resolution cattle contact structure data. Furthermore, we establish a modeling framework to track potential disease transmission dynamics and construct transmission network based on the observed animal contact network.

  11. Distinction and connection between contact network, social network, and disease transmission network.

    PubMed

    Chen, Shi; Lanzas, Cristina

    2016-09-01

    In this paper we discuss the distinction and connection between three closely related networks in animal ecology and epidemiology studies: the contact, social, and disease transmission networks. We provide a robust theoretical definition and interpretation of these three networks, demonstrate that social and disease transmission networks can be derived as spanning subgraphs of contact network, and show examples based on real-world high-resolution cattle contact structure data. Furthermore, we establish a modeling framework to track potential disease transmission dynamics and construct transmission network based on the observed animal contact network. PMID:27544246

  12. HIV / AIDS Network.

    PubMed

    1995-01-01

    The HIV/AIDS Network and the Philippines Department of Health (DOH) collaborated to produce the AIDS Candlelight Memorial at the Philippine International Convention Center (PICC), May 1995, and World AIDS Day activities on December 1, 1995. After the memorial, a fashion show, "Body Shots," provided a channel for information on acquired immunodeficiency syndrome (AIDS). On World AIDS Day, at the request of DOH, the Network provided speakers who lectured on human immunodeficiency virus (HIV) and AIDS in different government offices. Prior to World AIDS Day, the Network focused on strengthening its cohesiveness and building the capabilities of its member organizations through lectures and symposia during November. Network activities were coordinated by the Remedios AIDS Foundation with support from the other members of the Coordinating Council: Health Action Information Network (HAIN); Caritas; Kabalikat, Stop Trafficking of Pilopinos Foundation, Inc. (STOP);and the Library Foundation (TLF). The Coordinating Council elected for 1996 includes the Remedios AIDS Foundation, HAIN, Caritas, TLF, STOP, the Foundation for Adolescent Development (FAD), and the Salvation Army. PMID:12291699

  13. Viscoelastic Properties of Networks

    NASA Astrophysics Data System (ADS)

    Gündüz, Güngör

    A network was characterized by its viscoelastic properties. The viscoelastic property indicates the deformations or changes in the shape and in the internal structure during the evolution of a network. The change in the direction of motion was taken as elastic deformation and the change in the vertical direction as viscous deformation. These deformations were related to the change of geometry of internal structure and of shape. Thus it was possible to characterize a network by its storage and loss moduli. The change of the structure of a network during its evolution changes also its entropy. However entropy depends on the number of microstates of an already existing framework. As examples, two different systems (i) New York Stock Exchange and (ii) a melody were studied for their viscoelastic properties. The change of viscous property was compared with the change of different types of entropies such as configurational entropy, crossing entropy, and topological entropy. This last entropy was introduced and explained in the text. It was found out that there is no direct correspondence between the increase of entropy and the increase of viscous property of a network although they sometimes correlate with each other.

  14. The ANTARES observation network

    NASA Astrophysics Data System (ADS)

    Dogliotti, Ana I.; Ulloa, Osvaldo; Muller-Karger, Frank; Hu, Chuanmin; Murch, Brock; Taylor, Charles; Yuras, Gabriel; Kampel, Milton; Lutz, Vivian; Gaeta, Salvador; Gagliardini, Domingo A.; Garcia, Carlos A. E.; Klein, Eduardo; Helbling, Walter; Varela, Ramon; Barbieri, Elena; Negri, Ruben; Frouin, Robert; Sathyendranath, Shubha; Platt, Trevor

    2005-08-01

    The ANTARES network seeks to understand the variability of the coastal environment on a continental scale and the local, regional, and global factors and processes that effect this change. The focus are coastal zones of South America and the Caribbean Sea. The initial approach includes developing time series of in situ and satellite-based environmental observations in coastal and oceanic regions. The network is constituted by experts that seek to exchange ideas, develop an infrastructure for mutual logistical and knowledge support, and link in situ time series of observations located around the Americas with real-time and historical satellite-derived time series of relevant products. A major objective is to generate information that will be distributed publicly and openly in the service of coastal ocean research, resource management, science-based policy making and education in the Americas. As a first stage, the network has linked oceanographic time series located in Argentina, Brazil, Chile and Venezuela. The group has also developed an online tool to examine satellite data collected with sensors such as NASA's MODIS. Specifically, continental-scale high-resolution (1 km) maps of chlorophyll and of sea surface temperature are generated and served daily over the web according to specifications of users within the ANTARES network. Other satellite-derived variables will be added as support for the network is solidified. ANTARES serves data and offers simple analysis tools that anyone can use with the ultimate goal of improving coastal assessments, management and policies.

  15. Networks of Emotion Concepts

    PubMed Central

    Toivonen, Riitta; Kivelä, Mikko; Saramäki, Jari; Viinikainen, Mikko; Vanhatalo, Maija; Sams, Mikko

    2012-01-01

    The aim of this work was to study the similarity network and hierarchical clustering of Finnish emotion concepts. Native speakers of Finnish evaluated similarity between the 50 most frequently used Finnish words describing emotional experiences. We hypothesized that methods developed within network theory, such as identifying clusters and specific local network structures, can reveal structures that would be difficult to discover using traditional methods such as multidimensional scaling (MDS) and ordinary cluster analysis. The concepts divided into three main clusters, which can be described as negative, positive, and surprise. Negative and positive clusters divided further into meaningful sub-clusters, corresponding to those found in previous studies. Importantly, this method allowed the same concept to be a member in more than one cluster. Our results suggest that studying particular network structures that do not fit into a low-dimensional description can shed additional light on why subjects evaluate certain concepts as similar. To encourage the use of network methods in analyzing similarity data, we provide the analysis software for free use (http://www.becs.tkk.fi/similaritynets/). PMID:22276099

  16. Network modularity promotes cooperation.

    PubMed

    Marcoux, Marianne; Lusseau, David

    2013-05-01

    Cooperation in animals and humans is widely observed even if evolutionary biology theories predict the evolution of selfish individuals. Previous game theory models have shown that cooperation can evolve when the game takes place in a structured population such as a social network because it limits interactions between individuals. Modularity, the natural division of a network into groups, is a key characteristic of all social networks but the influence of this crucial social feature on the evolution of cooperation has never been investigated. Here, we provide novel pieces of evidence that network modularity promotes the evolution of cooperation in 2-person prisoner's dilemma games. By simulating games on social networks of different structures, we show that modularity shapes interactions between individuals favouring the evolution of cooperation. Modularity provides a simple mechanism for the evolution of cooperation without having to invoke complicated mechanisms such as reputation or punishment, or requiring genetic similarity among individuals. Thus, cooperation can evolve over wider social contexts than previously reported.

  17. French fireball network FRIPON

    NASA Astrophysics Data System (ADS)

    Colas, F.; Zanda, B.; Vaubaillon, J.; Bouley, S.; Marmo, C.; Audureau, Y.; Kwon, M. K.; Rault, J.-L.; Caminade, S.; Vernazza, P.; Gattacceca, J.; Birlan, M.; Maquet, L.; Egal, A.; Rotaru, M.; Birnbaum, C.; Cochard, F.; Thizy, O.

    2015-01-01

    FRIPON (Fireball Recovery and Interplanetary Observation Network) was recently founded by ANR (Agence Nationale de la Recherche), its aim being to connect meteoritical science with asteroidal and cometary sciences, in order to better understand our solar system formation and evolution. The main idea is to cover all the French territory to collect a large number of meteorites (one or two per year) with an accurate orbit determination, allowing to pinpoint possible parent bodies. 100 all-sky cameras will be installed at the end of 2015, creating a dense network with an average distance of 100 km between the stations. To maximize the accuracy of the orbit determination, we will mix our optical data with radar data from the GRAVES transmitter received by 25 stations (Rault et al., 2015). As the network installation and the creation of research teams for meteorites involves many persons, at least many more than our small team of professionals, we will develop a participative science network for amateurs called Vigie-Ciel (Zanda et al., 2015). It will be possible to simply use our data, participate in research campaigns or even add cameras to the FRIPON network.

  18. Genetic programming-based approach to elucidate biochemical interaction networks from data.

    PubMed

    Kandpal, Manoj; Kalyan, Chakravarthy Mynampati; Samavedham, Lakshminarayanan

    2013-02-01

    Biochemical systems are characterised by cyclic/reversible reciprocal actions, non-linear interactions and a mixed relationship structures (linear and non-linear; static and dynamic). Deciphering the architecture of such systems using measured data to provide quantitative information regarding the nature of relationships that exist between the measured variables is a challenging proposition. Causality detection is one of the methodologies that are applied to elucidate biochemical networks from such data. Autoregressive-based modelling approach such as granger causality, partial directed coherence, directed transfer function and canonical variate analysis have been applied on different systems for deciphering such interactions, but with limited success. In this study, the authors propose a genetic programming-based causality detection (GPCD) methodology which blends evolutionary computation-based procedures along with parameter estimation methods to derive a mathematical model of the system. Application of the GPCD methodology on five data sets that contained the different challenges mentioned above indicated that GPCD performs better than the other methods in uncovering the exact structure with less false positives. On a glycolysis data set, GPCD was able to fill the 'interaction gaps' which were missed by other methods.

  19. Whether information network supplements friendship network

    NASA Astrophysics Data System (ADS)

    Miao, Lili; Zhang, Qian-Ming; Nie, Da-Cheng; Cai, Shi-Min

    2015-02-01

    Homophily is a significant mechanism for link prediction in complex network, of which principle describes that people with similar profiles or experiences tend to tie with each other. In a multi-relationship network, friendship among people has been utilized to reinforce similarity of taste for recommendation system whose basic idea is similar to homophily, yet how the taste inversely affects friendship prediction is little discussed. This paper contributes to address the issue by analyzing two benchmark data sets both including user's behavioral information of taste and friendship based on the principle of homophily. It can be found that the creation of friendship tightly associates with personal taste. Especially, the behavioral information of taste involving with popular objects is much more effective to improve the performance of friendship prediction. However, this result seems to be contradictory to the finding in Zhang et al. (2013) that the behavior information of taste involving with popular objects is redundant in recommendation system. We thus discuss this inconformity to comprehensively understand the correlation between them.

  20. Quartets and unrooted phylogenetic networks.

    PubMed

    Gambette, Philippe; Berry, Vincent; Paul, Christophe

    2012-08-01

    Phylogenetic networks were introduced to describe evolution in the presence of exchanges of genetic material between coexisting species or individuals. Split networks in particular were introduced as a special kind of abstract network to visualize conflicts between phylogenetic trees which may correspond to such exchanges. More recently, methods were designed to reconstruct explicit phylogenetic networks (whose vertices can be interpreted as biological events) from triplet data. In this article, we link abstract and explicit networks through their combinatorial properties, by introducing the unrooted analog of level-k networks. In particular, we give an equivalence theorem between circular split systems and unrooted level-1 networks. We also show how to adapt to quartets some existing results on triplets, in order to reconstruct unrooted level-k phylogenetic networks. These results give an interesting perspective on the combinatorics of phylogenetic networks and also raise algorithmic and combinatorial questions.