The importance of international cooperation in the field of high level radioactive waste management

International Nuclear Information System (INIS)

Isaacs, Thomas H.

1992-01-01

This paper discusses the importance of international collaboration in the field of radioactive waste management and points out how cooperation has benefited the U.S. civilian waste management program. The U.S. Department of Energy's Office of Civilian Radioactive Waste Management (OCRWM) oversees the handling, transportation, storage, and final deposition of high-level radioactive wastes for the U.S. commercial sector. Because OCRWM shares many of the same waste management concerns as various other countries with nuclear programs, and since one country's waste management program will ultimately have an impact on the waste management programs of other countries, it is clearly in the interest of all countries to work together in search of solutions to common waste management problems. To facilitate this. cooperation, OCRWM is a participating member of international organizations, such as the IAEA and the OECD/NEA. OCRWM further has in place several bilateral agreements with various individual countries and with the Commission of the European Communities (CEC). Other international waste management initiatives are also currently being considered. (author)

On the international cooperation of North-West Russia in the field of innovations in the Baltic

Directory of Open Access Journals (Sweden)

Baranova Yulia

2012-12-01

Full Text Available This article focuses on the cooperation between the constituent entities of the Northwestern Federal District of the Russian Federation and the Baltic countries (Finland, Estonia, and Norway in the field of innovations at national and regional levels, as well as at the level of corporate cooperation. The author reviews successful implementation of innovation projects within cross-border and transnational cooperation programmes. The most significant projects focus on the development of information and communications technologies in healthcare, the development of networks uniting innovation centres in the Baltic Sea region, and the transnational network of business incubators in the Baltic Sea region. The author identifies promising areas of cooperation between North-West Russia, Finland, Norway, and Estonia in the field of innovations, including telecommunications, information and, space; biological, environmental and nanotechnologies; software, medicine, education, culture, energy efficiency and ecological construction, as well as the development of creative industries. The article pays attention to large-scale national projects, such as “St. Petersburg Corridor — Two Model Open Innovation Platform” and “Partnership in commercialization of Russian innovations”.

Bent dark soliton dynamics in two spatial dimensions beyond the mean field approximation

Science.gov (United States)

Mistakidis, Simeon; Katsimiga, Garyfallia; Koutentakis, Georgios; Kevrekidis, Panagiotis; Schmelcher, Peter; Theory Group of Fundamental Processes in Quantum Physics Team

2017-04-01

The dynamics of a bented dark soliton embedded in two spatial dimensions beyond the mean-field approximation is explored. We examine the case of a single bented dark soliton comparing the mean-field approximation to a correlated approach that involves multiple orbitals. Fragmentation is generally present and significantly affects the dynamics, especially in the case of stronger interparticle interactions and in that of lower atom numbers. It is shown that the presence of fragmentation allows for the appearance of solitonic and vortex structures in the higher-orbital dynamics. In particular, a variety of excitations including dark solitons in multiple orbitals and vortex-antidark complexes is observed to arise spontaneously within the beyond mean-field dynamics. Deutsche Forschungsgemeinschaft (DFG) in the framework of the SFB 925 ``Light induced dynamics and control of correlated quantum systems''.

Two-level systems driven by large-amplitude fields

Science.gov (United States)

Nori, F.; Ashhab, S.; Johansson, J. R.; Zagoskin, A. M.

2009-03-01

We analyze the dynamics of a two-level system subject to driving by large-amplitude external fields, focusing on the resonance properties in the case of driving around the region of avoided level crossing. In particular, we consider three main questions that characterize resonance dynamics: (1) the resonance condition, (2) the frequency of the resulting oscillations on resonance, and (3) the width of the resonance. We identify the regions of validity of different approximations. In a large region of the parameter space, we use a geometric picture in order to obtain both a simple understanding of the dynamics and quantitative results. The geometric approach is obtained by dividing the evolution into discrete time steps, with each time step described by either a phase shift on the basis states or a coherent mixing process corresponding to a Landau-Zener crossing. We compare the results of the geometric picture with those of a rotating wave approximation. We also comment briefly on the prospects of employing strong driving as a useful tool to manipulate two-level systems. S. Ashhab, J.R. Johansson, A.M. Zagoskin, F. Nori, Two-level systems driven by large-amplitude fields, Phys. Rev. A 75, 063414 (2007). S. Ashhab et al, unpublished.

Applicability of self-consistent mean-field theory

International Nuclear Information System (INIS)

Guo Lu; Sakata, Fumihiko; Zhao Enguang

2005-01-01

Within the constrained Hartree-Fock (CHF) theory, an analytic condition is derived to estimate whether a concept of the self-consistent mean field is realized in the level repulsive region. The derived condition states that an iterative calculation of the CHF equation does not converge when the quantum fluctuations coming from two-body residual interaction and quadrupole deformation become larger than a single-particle energy difference between two avoided crossing orbits. By means of numerical calculation, it is shown that the analytic condition works well for a realistic case

Time independent mean-field theory

International Nuclear Information System (INIS)

Negele, J.W.

1980-02-01

The physical and theoretical motivations for the time-dependent mean-field theory are presented, and the successes and limitations of the time-dependent Hartree-Fock initial-vaue problem are reviewed. New theoretical developments are described in the treatment of two-body correlations and the formulation of a quantum mean-field theory of large-amplitude collective motion and tunneling decay. Finally, the mean-field theory is used to obtain new insights into the phenomenon of pion condensation in finite nuclei. 18 figures

Information Entropy Squeezing of a Two-Level Atom Interacting with Two-Mode Coherent Fields

Institute of Scientific and Technical Information of China (English)

LIU Xiao-Juan; FANG Mao-Fa

2004-01-01

From a quantum information point of view we investigate the entropy squeezing properties for a two-level atom interacting with the two-mode coherent fields via the two-photon transition. We discuss the influences of the initial state of the system on the atomic information entropy squeezing. Our results show that the squeezed component number,squeezed direction, and time of the information entropy squeezing can be controlled by choosing atomic distribution angle,the relative phase between the atom and the two-mode field, and the difference of the average photon number of the two field modes, respectively. Quantum information entropy is a remarkable precision measure for the atomic squeezing.

Constitutive modeling of two phase materials using the Mean Field method for homogenization

NARCIS (Netherlands)

Perdahcioglu, Emin Semih; Geijselaers, Hubertus J.M.

2010-01-01

A Mean-Field homogenization framework for constitutive modeling of materials involving two distinct elastic-plastic phases is presented. With this approach it is possible to compute the macroscopic mechanical behavior of this type of materials based on the constitutive models of the constituent

The Meaning of and Proposals for Latin-American Cooperation in Psychology

OpenAIRE

Garcia, Agnaldo; Acevedo-Triana, César Andrés; López-López, Wilson

2015-01-01

The literature indicates several advantages and difficulties associated with international scientific cooperation. Due to the need to identify possible areas for cooperation between researchers in Latin America-a way of strengthening cooperation networks-the present qualitative study investigated the meaning of cooperation among Latin American authors and proposals to pursue this endeavor. A purposive sample of 26 researchers responded to 2 open questions. The responses were subjected to them...

MULTILATERAL COOPERATION IN THE BLACK SEA REGION IN THE ENERGY FIELD

Directory of Open Access Journals (Sweden)

Andrey Vyacheslavovich Ishin

2015-01-01

Full Text Available In the article the state of international cooperation is analysed in the field of energy in Black Sea besseyne. Problems and prospects of development of power communications, their influence, are examined on the level of international stability.

EU-China Cooperation In the Field of Energy, Environment and Climate Change

Directory of Open Access Journals (Sweden)

Pietro De Matteis

2010-11-01

Full Text Available The evolution of the energy market and the intrinsic worldwide scope of environmental threats, such as climate change, are two elements that have pushed the world towards shared approaches to global governance via bilateral institutions and international regimes. This article, with the aid of an institutionalist approach, presents the current status of the EU-China relationship, which is characterised by high institutionalisation, and it underlines how their bilateral cooperation has progressively focused on energy and climate change-related issues. In particular, the article sheds some light on the linkages between energy, environment and climate change and how these have created the basis for the upgrade of the EU-China bilateral relationship to its current level. To do so, it underlines some of the tools, the main frameworks and some of the key outcomes of their bilateral cooperation in these fields.

Dynamical Mean Field Approximation Applied to Quantum Field Theory

CERN Document Server

Akerlund, Oscar; Georges, Antoine; Werner, Philipp

2013-12-04

We apply the Dynamical Mean Field (DMFT) approximation to the real, scalar phi^4 quantum field theory. By comparing to lattice Monte Carlo calculations, perturbation theory and standard mean field theory, we test the quality of the approximation in two, three, four and five dimensions. The quantities considered in these tests are the critical coupling for the transition to the ordered phase and the associated critical exponents nu and beta. We also map out the phase diagram in four dimensions. In two and three dimensions, DMFT incorrectly predicts a first order phase transition for all bare quartic couplings, which is problematic, because the second order nature of the phase transition of lattice phi^4-theory is crucial for taking the continuum limit. Nevertheless, by extrapolating the behaviour away from the phase transition, one can obtain critical couplings and critical exponents. They differ from those of mean field theory and are much closer to the correct values. In four dimensions the transition is sec...

A Two-Mode Mean-Field Optimal Switching Problem for the Full Balance Sheet

Directory of Open Access Journals (Sweden)

Boualem Djehiche

2014-01-01

a two-mode optimal switching problem of mean-field type, which can be described by a system of Snell envelopes where the obstacles are interconnected and nonlinear. The main result of the paper is a proof of a continuous minimal solution to the system of Snell envelopes, as well as the full characterization of the optimal switching strategy.

Effect of Aspiration and Mean Gain on the Emergence of Cooperation in Unidirectional Pedestrian Flow

International Nuclear Information System (INIS)

Wang Zi-Yang; Zhao Hui; Ma Jian; Qin Yong; Jia Li-Min; Zhu Wei

2013-01-01

When more than one pedestrian want to move to the same site, conflicts appear and thus the involved pedestrians play a motion game. In order to describe the emergence of cooperation during the conflict resolving process, an evolutionary cellular automation model is established considering the effect of aspiration and mean gain. In each game, pedestrian may be gentle cooperator or aggressive defector. We propose a set of win-stay-lose-shrift (WSLS) like rules for updating pedestrian's strategy. These rules prescribe that if the mean gain of current strategy between some given steps is larger than aspiration the strategy keeps, otherwise the strategy changes. The simulation results show that a high level aspiration will lead to more cooperation. With the increment of the statistic length, pedestrians will be more rational in decision making. It is also found that when the aspiration level is small enough and the statistic length is large enough all the pedestrian will turn to defectors. We use the prisoner's dilemma model to explain it. At last we discuss the effect of aspiration on fundamental diagram. (interdisciplinary physics and related areas of science and technology)

Weathering the competition through cooperation at customer service level; Erfolgreich im Wettbewerb durch Kooperation im Kundenservice

Energy Technology Data Exchange (ETDEWEB)

Quante, Katrin [VISOS GmbH, Moers (Germany)

2012-01-15

Rising customer churn rates in the wake of stiffening competition are aggravating the cost pressure on energy supply companies. More and more energy suppliers are seeking cooperations as a means of countering the growing cost pressure, rapidity of change and growing complexity of their workflows. Especially small and medium-sized utilities see this as an appropriate means of holding their own against large energy suppliers. In other branches of industry inter-company cooperations at the economic or technical level are already established practice. Recent project experiences have shown that such cooperation models can be transferred with equal success to the energy sector at customer service level.

International cooperation in the field of radiation application

International Nuclear Information System (INIS)

Sato, Shoichi

1993-01-01

Bilateral and multilateral research cooperations have been implemented at TRCRE, JAERI, producing favourable results in the field of radiation application. Frameworks and some achievements are described and the significance of the international cooperation is discussed. (Author)

Mean-field models and exotic nuclei

Energy Technology Data Exchange (ETDEWEB)

Bender, M; Buervenich, T; Maruhn, J A; Greiner, W [Inst. fuer Theoretische Physik, Univ. Frankfurt (Germany); Rutz, K [Inst. fuer Theoretische Physik, Univ. Frankfurt (Germany); [Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany); Reinhard, P G [Inst. fuer Theoretische Physik, Univ. Erlangen (Germany)

1998-06-01

We discuss two widely used nuclear mean-field models, the relativistic mean-field model and the (nonrelativistic) Skyrme-Hartree-Fock model, and their capability to describe exotic nuclei. Test cases are superheavy nuclei and neutron-rich Sn isotopes. New information in this regime helps to fix hitherto loosely determined aspects of the models. (orig.)

Mean-field models and exotic nuclei

International Nuclear Information System (INIS)

Bender, M.; Buervenich, T.; Maruhn, J.A.; Greiner, W.; Rutz, K.; Reinhard, P.G.

1998-01-01

We discuss two widely used nuclear mean-field models, the relativistic mean-field model and the (nonrelativistic) Skyrme-Hartree-Fock model, and their capability to describe exotic nuclei. Test cases are superheavy nuclei and neutron-rich Sn isotopes. New information in this regime helps to fix hitherto loosely determined aspects of the models. (orig.)

The evolution of cooperation in spatial groups

International Nuclear Information System (INIS)

Zhang Jianlei; Zhang Chunyan; Chu Tianguang

2011-01-01

Research highlights: → We propose a model of evolutionary games in which individuals are organized into networked groups. → We show that the social dilemma can be resolved and high cooperation levels are attained. → Larger average group size would lead to lower cooperation level but higher average payoffs. → The results show that higher expectations can bring the system with larger average payoffs. - Abstract: Much of human cooperation remains an evolutionary riddle. There is evidence that individuals are often organized into groups in many social situations. Inspired by this observation, we propose a simple model of evolutionary public goods games in which individuals are organized into networked groups. Here, nodes in the network represent groups; the edges, connecting the nodes, refer to the interactions between the groups. Individuals establish public goods games with partners in the same group and migrate among neighboring groups depending on their payoffs and expectations. We show that the paradigmatic public goods social dilemma can be resolved and high cooperation levels are attained in structured groups, even in relatively harsh conditions for cooperation. Further, by means of numerical simulations and mean-field analysis, we arrive at the result: larger average group size and milder cooperation environment would lead to lower cooperation level but higher average payoffs of the entire population. Altogether, these results emphasize that our understanding of cooperation can be enhanced by investigations of how spatial groups of individuals affect the evolution dynamics, which might help in explaining the emergence and evolution of cooperation.

Two-level systems driven by large-amplitude fields

International Nuclear Information System (INIS)

Ashhab, S.; Johansson, J. R.; Zagoskin, A. M.; Nori, Franco

2007-01-01

We analyze the dynamics of a two-level system subject to driving by large-amplitude external fields, focusing on the resonance properties in the case of driving around the region of avoided level crossing. In particular, we consider three main questions that characterize resonance dynamics: (1) the resonance condition (2) the frequency of the resulting oscillations on resonance, and (3) the width of the resonance. We identify the regions of validity of different approximations. In a large region of the parameter space, we use a geometric picture in order to obtain both a simple understanding of the dynamics and quantitative results. The geometric approach is obtained by dividing the evolution into discrete time steps, with each time step described by either a phase shift on the basis states or a coherent mixing process corresponding to a Landau-Zener crossing. We compare the results of the geometric picture with those of a rotating wave approximation. We also comment briefly on the prospects of employing strong driving as a useful tool to manipulate two-level systems

Two-dimensional atom localization via two standing-wave fields in a four-level atomic system

International Nuclear Information System (INIS)

Zhang Hongtao; Wang Hui; Wang Zhiping

2011-01-01

We propose a scheme for the two-dimensional (2D) localization of an atom in a four-level Y-type atomic system. By applying two orthogonal standing-wave fields, the atoms can be localized at some special positions, leading to the formation of sub-wavelength 2D periodic spatial distributions. The localization peak position and number as well as the conditional position probability can be controlled by the intensities and detunings of optical fields.

Mean-field energy-level shifts and dielectric properties of strongly polarized Rydberg gases

OpenAIRE

Zhelyazkova, V.; Jirschik, R.; Hogan, S. D.

2016-01-01

Mean-field energy-level shifts arising as a result of strong electrostatic dipole interactions within dilute gases of polarized helium Rydberg atoms have been probed by microwave spectroscopy. The Rydberg states studied had principal quantum numbers n=70 and 72, and electric dipole moments of up to 14 050 D, and were prepared in pulsed supersonic beams at particle number densities on the order of 108 cm−3. Comparisons of the experimental data with the results of Monte Carlo calculations highl...

Cooperation arrangements related to technology transfer

International Nuclear Information System (INIS)

Eysel, G.

1986-04-01

A developing country which considers to launch a nuclear program should put as much as possible efforts to elaborate a program which suits the country's needs as well as reflects its capabilities. It deems advantageous that a developing country makes use of the experience and knowledge in the nuclear field of a partner country already in the phase when exploring the technical and commercial aspects of a nuclear power program. For the different stages of cooperation between two countries a three-level concept appears advisable for establishing the basis for individual cooperation agreement. The first level are agreements between the governments of both countries on joint scientific research projects and technical development programs covering a broad spectrum of activities not limited to the energy sector. At the second level cooperation agreements can already concentrate on the energy sector and e.g. specifically investigate the energy structure of the developing country. If this investigation results in the decision of the developing country to establish a nuclear power program the next level will cover a broad based cooperation in the nuclear field including a large number of different cooperation contracts in various fields. In this stage of bilateral cooperation the main emphasis will be put on industrial cooperation. Cooperation agreements to be concluded between respective partners of both countries may cover fields related to research and development, engineering of a nuclear power plant, manufacturing of its components, erection and installation as well as operation of the plant. The most common agreements refer to technical cooperation, which covers not only the transfer of blueprints but also training of the recipient's personnel in the partner's country and delegation of experts to the recipient's country. The most comprehensive form of cooperation is the foundation of a joint venture company where the technology partner does not only transfer his know

Strong temperature effect on the sizes of the Cooper pairs in a two-band superconductor

Science.gov (United States)

Örd, Teet; Rägo, Küllike; Vargunin, Artjom; Litak, Grzegorz

2018-01-01

We study the temperature dependencies of the mean sizes of the Cooper pairs in a two-band BCS-type s-wave superconductivity model with coupling cut-off in the momentum space. It is found that, in contrast to single-band systems, the size of Cooper pairs in the weaker superconductivity band can significantly decrease with a temperature increase due to an interband proximity effect. The relevant spatial behaviour of the wave functions of the Cooper pairs is analyzed. The results also indicate a possibility that the size of Cooper pairs in two-band systems may increase with an increase in temperature.

European cooperation in the field of security and defence. International Relation theories perspective

Directory of Open Access Journals (Sweden)

Jacek Czaputowicz

2014-06-01

Full Text Available The paper discusses various theoretical explanations of the European cooperation in the field of security and defence. According to realist explanations this cooperation was a response to external evolutions in the international system, i.e. changes in polarity and distribution of power. Liberals say that it was rather due to internal factors. Constructivists argue that it was a result of elites’ socialisation, while according to Pierre Bourdieu’s field theory, it was caused by civil servants and military staff at the policy implementation level. The paper argues that external factors underlined by realists were decisive, i.e. America’s decreasing involvement in European security.

Mean-field models and superheavy elements

International Nuclear Information System (INIS)

Reinhard, P.G.; Bender, M.; Maruhn, J.A.; Frankfurt Univ.

2001-03-01

We discuss the performance of two widely used nuclear mean-field models, the relativistic mean-field theory (RMF) and the non-relativistic Skyrme-Hartree-Fock approach (SHF), with particular emphasis on the description of superheavy elements (SHE). We provide a short introduction to the SHF and RMF, the relations between these two approaches and the relations to other nuclear structure models, briefly review the basic properties with respect to normal nuclear observables, and finally present and discuss recent results on the binding properties of SHE computed with a broad selection of SHF and RMF parametrisations. (orig.)

Skyrme-Hartree-Fock in the realm of nuclear mean field models

International Nuclear Information System (INIS)

Reinhard, P.G.; Reiss, C.; Maruhn, J.; Bender, M.; Buervenich, T.; Greiner, W.

2000-01-01

We discuss and compare two brands of nuclear mean field models, the Skyrme-Hartree-Fock scheme (SHF) and the relativistic mean field model (RMF). Similarities and differences are worked out on a formal basis and with respect to the models performance in describing nuclear data. The bulk observables of stable nuclei are all described very well. Differences come up when extrapolating to exotic nuclei. The typically larger asymmetry energy in RMF leads to a larger neutron skin. Superheavy nuclei are found to be very sensitive on the single particle levels particularly on the spin orbit splitting. Ground state correlations from collective surface vibrations can have a significant effect on difference observables, as two-nucleon separation energy and two-nucleon shell gap. (author)

Cooperative SIS epidemics can lead to abrupt outbreaks

Science.gov (United States)

Ghanbarnejad, Fakhteh; Chen, Li; Cai, Weiran; Grassberger, Peter

2015-03-01

In this paper, we study spreading of two cooperative SIS epidemics in mean field approximations and also within an agent based framework. Therefore we investigate dynamics on different topologies like Erdos-Renyi networks and regular lattices. We show that cooperativity of two diseases can lead to strongly first order outbreaks, while the dynamics still might present some scaling laws typical for second order phase transitions. We argue how topological network features might be related to this interesting hybrid behaviors.

Random model of two-level atoms interacting with electromagnetic field

International Nuclear Information System (INIS)

Kireev, A.N.; Meleshko, A.N.

1983-12-01

A phase transition has been studied in a random system of two-level atoms interacting with an electromagnetic field. It is shown that superradiation can arise when there is short-range order in a spin-subsystem. The existence of long-range order is irrelevant for this phase transition

Proposals for regional cooperation in Africa

International Nuclear Information System (INIS)

Diaco, T.

1999-01-01

This presentation includes proposals for regional cooperation in Africa in the field of seismic monitoring and proposes future actions for establishing this cooperation. It emphasises the benefits of regional cooperation meaning scientific benefit from an established data base, as well as benefit in the field of geology, meteorology, geophysics and in unified budgets and logistics

The two-wave X-ray field calculated by means of integral-equation methods

International Nuclear Information System (INIS)

Bremer, J.

1984-01-01

The problem of calculating the two-wave X-ray field on the basis of the Takagi-Taupin equations is discussed for the general case of curved lattice planes. A two-dimensional integral equation which incorporates the nature of the incoming radiation, the form of the crystal/vacuum boundary, and the curvature of the structure, is deduced. Analytical solutions for the symmetrical Laue case with incoming plane waves are obtained directly for perfect crystals by means of iteration. The same method permits a simple derivation of the narrow-wave Laue and Bragg cases. Modulated wave fronts are discussed, and it is shown that a cut-off in the width of an incoming plane wave leads to lateral oscillations which are superimposed on the Pendelloesung fringes. Bragg and Laue shadow fields are obtained. The influence of a non-zero kernel is discussed and a numerical procedure for calculating wave amplitudes in curved crystals is presented. (Auth.)

European Administrative Cooperation in the Field of Taxation

Directory of Open Access Journals (Sweden)

Florin TUDOR

2012-04-01

Full Text Available The operation of different taxation systems in EU member states appears to promote more increasingly the appearance of double taxation entailing fraud and tax evasion. The phenomenon is amplified by the remaining control competences at the national level, and the lack of administrative cooperation in tax matters at EU level is being a decisive factor in delaying the causes with the consequence of prescription of the facts which brings serious damage enhanced EU budget. This study aims to examine the legal ways and means to ensure that the information, reports, statements and other documents mandatory to the administrative or judicial proceedings to be legal required from the counterparts existing in other members states invoked as evidence by their competent bodies.

Exotic nuclei in self-consistent mean-field models

International Nuclear Information System (INIS)

Bender, M.; Rutz, K.; Buervenich, T.; Reinhard, P.-G.; Maruhn, J. A.; Greiner, W.

1999-01-01

We discuss two widely used nuclear mean-field models, the relativistic mean-field model and the (nonrelativistic) Skyrme-Hartree-Fock model, and their capability to describe exotic nuclei with emphasis on neutron-rich tin isotopes and superheavy nuclei. (c) 1999 American Institute of Physics

Mean field games

KAUST Repository

Gomes, Diogo A.

2014-01-06

In this talk we will report on new results concerning the existence of smooth solutions for time dependent mean-field games. This new result is established through a combination of various tools including several a-priori estimates for time-dependent mean-field games combined with new techniques for the regularity of Hamilton-Jacobi equations.

Mean field games

KAUST Repository

Gomes, Diogo A.

2014-01-01

In this talk we will report on new results concerning the existence of smooth solutions for time dependent mean-field games. This new result is established through a combination of various tools including several a-priori estimates for time-dependent mean-field games combined with new techniques for the regularity of Hamilton-Jacobi equations.

Polynomial pseudosupersymmetry underlying a two-level atom in an external electromagnetic field

International Nuclear Information System (INIS)

Samsonov, B.F.; Shamshutdinova, V.V.; Gitman, D.M.

2005-01-01

Chains of transformations introduced previously were studied in order to obtain electric fields with a time-dependent frequency for which the equation of motion of a two-level atom in the presence of these fields can be solved exactly. It is shown that a polynomial pseudosupersymmetry may be associated to such chains

International Cooperation of the Republic of Croatia in the Field of Nuclear Safety

International Nuclear Information System (INIS)

Novosel, N.; Rosandic, L.

2010-01-01

International cooperation of the Republic of Croatia in the field of nuclear safety can be divided in two parts - political part, for which the Ministry of Foreign Affairs and European Integration is responsible, and technical part, for which the State Office for Nuclear Safety is responsible, in cooperation with other state administration bodies, where applicable. According to the Nuclear Safety Act (OG 73/2003) the State Office for Nuclear Safety: 'coordinates technical cooperation with the International Atomic Energy Agency for all participants from the Republic of Croatia'; 'fulfills the obligations which the Republic of Croatia has assumed through international conventions and bilateral agreements concerning nuclear safety and the application of protective measures aimed at the non-proliferation of nuclear weapons' and 'cooperates with international organizations and associations in the area of nuclear safety, and appoints its own expert representatives to take part in the work of such organizations and associations or to monitor their work'. In this paper various aspects of the technical cooperation with the International Atomic Energy Agency, as well as international conventions and bilateral agreements in the field of nuclear safety, will be presented. Also, cooperation with other international organizations and associations in the nuclear area, such as Nuclear Suppliers Group, Zangger Committee, Wassenaar Arrangement, Comprehensive Nuclear-Test-Ban Treaty Organization, Euratom and certain civil expert groups of NATO, will be described.(author).

Level playing field with political tact

International Nuclear Information System (INIS)

Onderstal, S.; Appelman, M.

2004-01-01

Businesses, interest groups and policy administrators plead for a level playing field. However, those administrators interpret the level playing field notion in different ways and thus create confusion. In this article the level playing field is explained and a framework discussed by means of which the government can study policy problems in which the level playing field is of importance [nl

Cooperative Localization for Mobile Networks

DEFF Research Database (Denmark)

Cakmak, Burak; Urup, Daniel Nygaard; Meyer, Florian

2016-01-01

We propose a hybrid message passing method for distributed cooperative localization and tracking of mobile agents. Belief propagation and mean field message passing are employed for, respectively, the motion-related and measurementrelated part of the factor graph. Using a Gaussian belief approxim......We propose a hybrid message passing method for distributed cooperative localization and tracking of mobile agents. Belief propagation and mean field message passing are employed for, respectively, the motion-related and measurementrelated part of the factor graph. Using a Gaussian belief...

Non-local correlations within dynamical mean field theory

Energy Technology Data Exchange (ETDEWEB)

Li, Gang

2009-03-15

The contributions from the non-local fluctuations to the dynamical mean field theory (DMFT) were studied using the recently proposed dual fermion approach. Straight forward cluster extensions of DMFT need the solution of a small cluster, where all the short-range correlations are fully taken into account. All the correlations beyond the cluster scope are treated in the mean-field level. In the dual fermion method, only a single impurity problem needs to be solved. Both the short and long-range correlations could be considered on equal footing in this method. The weak-coupling nature of the dual fermion ensures the validity of the finite order diagram expansion. The one and two particle Green's functions calculated from the dual fermion approach agree well with the Quantum Monte Carlo solutions, and the computation time is considerably less than with the latter method. The access of the long-range order allows us to investigate the collective behavior of the electron system, e.g. spin wave excitations. (orig.)

Non-local correlations within dynamical mean field theory

International Nuclear Information System (INIS)

Li, Gang

2009-03-01

The contributions from the non-local fluctuations to the dynamical mean field theory (DMFT) were studied using the recently proposed dual fermion approach. Straight forward cluster extensions of DMFT need the solution of a small cluster, where all the short-range correlations are fully taken into account. All the correlations beyond the cluster scope are treated in the mean-field level. In the dual fermion method, only a single impurity problem needs to be solved. Both the short and long-range correlations could be considered on equal footing in this method. The weak-coupling nature of the dual fermion ensures the validity of the finite order diagram expansion. The one and two particle Green's functions calculated from the dual fermion approach agree well with the Quantum Monte Carlo solutions, and the computation time is considerably less than with the latter method. The access of the long-range order allows us to investigate the collective behavior of the electron system, e.g. spin wave excitations. (orig.)

Critical study of the dispersive n- 90Zr mean field by means of a new variational method

Science.gov (United States)

Mahaux, C.; Sartor, R.

1994-02-01

A new variational method is developed for the construction of the dispersive nucleon-nucleus mean field at negative and positive energies. Like the variational moment approach that we had previously proposed, the new method only uses phenomenological optical-model potentials as input. It is simpler and more flexible than the previous approach. It is applied to a critical investigation of the n- 90Zr mean field between -25 and +25 MeV. This system is of particular interest because conflicting results had recently been obtained by two different groups. While the imaginary parts of the phenomenological optical-model potentials provided by these two groups are similar, their real parts are quite different. Nevertheless, we demonstrate that these two sets of phenomenological optical-model potentials are both compatible with the dispersion relation which connects the real and imaginary parts of the mean field. Previous hints to the contrary, by one of the two other groups, are shown to be due to unjustified approximations. A striking outcome of the present study is that it is important to explicitly introduce volume absorption in the dispersion relation, although volume absorption is negligible in the energy domain investigated here. Because of the existence of two sets of phenomenological optical-model potentials, our variational method yields two dispersive mean fields whose real parts are quite different at small or negative energies. No preference for one of the two dispersive mean fields can be expressed on purely empirical grounds since they both yield fair agreement with the experimental cross sections as well as with the observed energies of the bound single-particle states. However, we argue that one of these two mean fields is physically more meaningful, because the radial shape of its Hartree-Fock type component is independent of energy, as expected on theoretical grounds. This preferred mean field is very close to the one which had been obtained by the Ohio

Magnetic Field Tuning and Quantum Interference in a Cooper Pair Splitter.

Science.gov (United States)

Fülöp, G; Domínguez, F; d'Hollosy, S; Baumgartner, A; Makk, P; Madsen, M H; Guzenko, V A; Nygård, J; Schönenberger, C; Levy Yeyati, A; Csonka, S

2015-11-27

Cooper pair splitting (CPS) is a process in which the electrons of the naturally occurring spin-singlet pairs in a superconductor are spatially separated using two quantum dots. Here, we investigate the evolution of the conductance correlations in an InAs CPS device in the presence of an external magnetic field. In our experiments the gate dependence of the signal that depends on both quantum dots continuously evolves from a slightly asymmetric Lorentzian to a strongly asymmetric Fano-type resonance with increasing field. These experiments can be understood in a simple three-site model, which shows that the nonlocal CPS leads to symmetric line shapes, while the local transport processes can exhibit an asymmetric shape due to quantum interference. These findings demonstrate that the electrons from a Cooper pair splitter can propagate coherently after their emission from the superconductor and how a magnetic field can be used to optimize the performance of a CPS device. In addition, the model calculations suggest that the estimate of the CPS efficiency in the experiments is a lower bound for the actual efficiency.

A two-site mean field model of discontinuous dynamic recrystallization

International Nuclear Information System (INIS)

Bernard, P.; Bag, S.; Huang, K.; Loge, R.E.

2011-01-01

Highlights: → Discontinuous dynamic recrystallization (DDRX) is modelled at the grain scale. → The two-site mean field approach allows introducing topological information. → DDRX kinetics, flow stress curves and recrystallized grain size are well predicted. → Temperature, strain rate and initial grain size effects are successfully described. → Grain size dependence naturally emerges from the model and agrees with experiment. - Abstract: The paper describes a new model of discontinuous dynamic recrystallization (DDRX) which can operate in constant or variable thermomechanical conditions. The model considers the elementary physical phenomena at the grain scale such as strain hardening, recovery, grain boundary migration, and nucleation. The microstructure is represented through a set of representative grains defined by their size and dislocation density. It is linked to a constitutive law giving access to the polycrystal flow stress. Interaction between representative grains and the surrounding material is idealized using a two-site approach whereby two homogeneous equivalent media with different dislocation densities are considered. Topological information is incorporated into the model by prescribing the relative weight of these two equivalent media as a function of their volume fractions. This procedure allows accounting for the well-known necklace structures. The model is applied to the prediction of DDRX in 304 L stainless steel, with parameters identified using an inverse methodology based on a genetic algorithm. Results show good agreement with experimental data at different temperatures and strain rates, predicting recrystallization kinetics, recrystallized grain size and stress-strain curve. Parameters identified with one initial grain size lead to accurate results for another initial grain size without introducing any additional parameter.

A Two-Species Cooperative Lotka-Volterra System of Degenerate Parabolic Equations

OpenAIRE

Sun, Jiebao; Zhang, Dazhi; Wu, Boying

2011-01-01

We consider a cooperating two-species Lotka-Volterra model of degenerate parabolic equations. We are interested in the coexistence of the species in a bounded domain. We establish the existence of global generalized solutions of the initial boundary value problem by means of parabolic regularization and also consider the existence of the nontrivial time-periodic solution for this system.

International cooperation in highly technological fields, especially in the field of aeronautics and astronautics and nuclear engineering

International Nuclear Information System (INIS)

Schunk, G.

1982-01-01

The subject of the study is the analysis of Research and Development (RandD) cooperation in highly technological fields. The study deals in particular with the reasons for cooperation, the aims and types of cooperation, with cooperating partners, as well as with alternative solutions and possible future developments. Special attention is given to those factors, which necessitate cooperation, and to aspects of possible alternatives and future developments. (orig.) [de

Controlling the optical bistability and multistability in a two-level pumped-probe system

International Nuclear Information System (INIS)

Mahmoudi, Mohammad; Sahrai, Mostafa; Masoumeh Mousavi, Seyede

2010-01-01

We study the behavior of the optical bistability (OB) and multistability (OM) in a two-level pumped-probe atomic system by means of a unidirectional ring cavity. We show that the optical bistability in a two-level atomic system can be controlled by adjusting the intensity of the pump field and the detuning between two fields. We find that applying the pumping field decreases the threshold of the optical bistability.

Risk-sensitive mean-field games

KAUST Repository

Tembine, Hamidou

2014-04-01

In this paper, we study a class of risk-sensitive mean-field stochastic differential games. We show that under appropriate regularity conditions, the mean-field value of the stochastic differential game with exponentiated integral cost functional coincides with the value function satisfying a Hamilton -Jacobi- Bellman (HJB) equation with an additional quadratic term. We provide an explicit solution of the mean-field best response when the instantaneous cost functions are log-quadratic and the state dynamics are affine in the control. An equivalent mean-field risk-neutral problem is formulated and the corresponding mean-field equilibria are characterized in terms of backward-forward macroscopic McKean-Vlasov equations, Fokker-Planck-Kolmogorov equations, and HJB equations. We provide numerical examples on the mean field behavior to illustrate both linear and McKean-Vlasov dynamics. © 1963-2012 IEEE.

Risk-sensitive mean-field games

KAUST Repository

Tembine, Hamidou; Zhu, Quanyan; Başar, Tamer

2014-01-01

In this paper, we study a class of risk-sensitive mean-field stochastic differential games. We show that under appropriate regularity conditions, the mean-field value of the stochastic differential game with exponentiated integral cost functional coincides with the value function satisfying a Hamilton -Jacobi- Bellman (HJB) equation with an additional quadratic term. We provide an explicit solution of the mean-field best response when the instantaneous cost functions are log-quadratic and the state dynamics are affine in the control. An equivalent mean-field risk-neutral problem is formulated and the corresponding mean-field equilibria are characterized in terms of backward-forward macroscopic McKean-Vlasov equations, Fokker-Planck-Kolmogorov equations, and HJB equations. We provide numerical examples on the mean field behavior to illustrate both linear and McKean-Vlasov dynamics. © 1963-2012 IEEE.

The Two-Level Theory of verb meaning: An approach to integrating the semantics of action with the mirror neuron system.

Science.gov (United States)

Kemmerer, David; Gonzalez-Castillo, Javier

2010-01-01

Verbs have two separate levels of meaning. One level reflects the uniqueness of every verb and is called the "root". The other level consists of a more austere representation that is shared by all the verbs in a given class and is called the "event structure template". We explore the following hypotheses about how, with specific reference to the motor features of action verbs, these two distinct levels of semantic representation might correspond to two distinct levels of the mirror neuron system. Hypothesis 1: Root-level motor features of verb meaning are partially subserved by somatotopically mapped mirror neurons in the left primary motor and/or premotor cortices. Hypothesis 2: Template-level motor features of verb meaning are partially subserved by representationally more schematic mirror neurons in Brodmann area 44 of the left inferior frontal gyrus. Evidence has been accumulating in support of the general neuroanatomical claims made by these two hypotheses-namely, that each level of verb meaning is associated with the designated cortical areas. However, as yet no studies have satisfied all the criteria necessary to support the more specific neurobiological claims made by the two hypotheses-namely, that each level of verb meaning is associated with mirror neurons in the pertinent brain regions. This would require demonstrating that within those regions the same neuronal populations are engaged during (a) the linguistic processing of particular motor features of verb meaning, (b) the execution of actions with the corresponding motor features, and (c) the observation of actions with the corresponding motor features. 2008 Elsevier Inc. All rights reserved.

Paired structures, imprecision types and two-level knowledge representation by means of opposites

DEFF Research Database (Denmark)

Rodríguez, J. Tinguaro; Franco de los Ríos, Camilo; Gómez, Daniel

2016-01-01

Opposition-based models are a current hot-topic in knowledge representation. The point of this paper is to suggest that opposition can be in fact introduced at two different levels, those of the predicates of interest being represented (as short/tall) and of the logical references (true/false) used...... to evaluate the verification of the former. We study this issue by means of the consideration of different paired structures at each level. We also pay attention at how different types of fuzziness may be introduced in these paired structures to model imprecision and lack of knowledge. As a consequence, we...

Entanglement for a Bimodal Cavity Field Interacting with a Two-Level Atom

International Nuclear Information System (INIS)

Liu Jia; Chen Ziyu; Bu Shenping; Zhang Guofeng

2009-01-01

Negativity has been adopted to investigate the entanglement in a system composed of a two-level atom and a two-mode cavity field. Effects of Kerr-like medium and the number of photon inside the cavity on the entanglement are studied. Our results show that atomic initial state must be superposed, so that the two cavity field modes can be entangled. Moreover, we also conclude that the number of photon in the two cavity mode should be equal. The interaction between modes, namely, the Kerr effect, has a significant negative contribution. Note that the atom frequency and the cavity frequency have an indistinguishable effect, so a corresponding approximation has been made in this article. These results may be useful for quantum information in optics systems.

Classification of networks of automata by dynamical mean field theory

International Nuclear Information System (INIS)

Burda, Z.; Jurkiewicz, J.; Flyvbjerg, H.

1990-01-01

Dynamical mean field theory is used to classify the 2 24 =65,536 different networks of binary automata on a square lattice with nearest neighbour interactions. Application of mean field theory gives 700 different mean field classes, which fall in seven classes of different asymptotic dynamics characterized by fixed points and two-cycles. (orig.)

Intermunicipal cooperation, public spending and service levels

NARCIS (Netherlands)

Allers, Maarten A.; de Greef, J.A.

2018-01-01

Local governments can increase size in particular policy fields through cooperation with other local governments. This is often thought to improve efficiency, but there is little empirical evidence supporting this hypothesis. We study the case of the Netherlands, which has been a veritable

Two-dimensional atom localization based on coherent field controlling in a five-level M-type atomic system.

Science.gov (United States)

Jiang, Xiangqian; Li, Jinjiang; Sun, Xiudong

2017-12-11

We study two-dimensional sub-wavelength atom localization based on the microwave coupling field controlling and spontaneously generated coherence (SGC) effect. For a five-level M-type atom, introducing a microwave coupling field between two upper levels and considering the quantum interference between two transitions from two upper levels to lower levels, the analytical expression of conditional position probability (CPP) distribution is obtained using the iterative method. The influence of the detuning of a spontaneously emitted photon, Rabi frequency of the microwave field, and the SGC effect on the CPP are discussed. The two-dimensional sub-half-wavelength atom localization with high-precision and high spatial resolution is achieved by adjusting the detuning and the Rabi frequency, where the atom can be localized in a region smaller thanλ/10×λ/10. The spatial resolution is improved significantly compared with the case without the microwave field.

O mezhdunarodnom sotrudnichestve Severo-Zapada Rossii v innovacionnoj sfere na Baltike [On the international cooperation of North-West Russia in the field of innovations in the Baltic

Directory of Open Access Journals (Sweden)

Baranova Yulia

2012-01-01

Full Text Available This article focuses on the cooperation between the constituent entities of the Northwestern Federal District of the Russian Federation and the Baltic countries (Finland, Estonia, and Norway in the field of innovations at national and regional levels, as well as at the level of corporate cooperation. The author reviews successful implementation of innovation projects within cross-border and transnational cooperation programmes. The most significant projects focus on the development of information and communications technologies in healthcare, the development of networks uniting innovation centres in the Baltic Sea region, and the transnational network of business incubators in the Baltic Sea region. The author identifies promising areas of cooperation between North-West Russia, Finland, Norway, and Estonia in the field of innovations, including telecommunications, information and, space; biological, environmental and nanotechnologies; software, medicine, education, culture, energy efficiency and ecological construction, as well as the development of creative industries. The article pays attention to large-scale national projects, such as “St. Petersburg Corridor — Two Model Open Innovation Platform” and “Partnership in commercialization of Russian innovations”.

Protecting quantum coherence of two-level atoms from vacuum fluctuations of electromagnetic field

International Nuclear Information System (INIS)

Liu, Xiaobao; Tian, Zehua; Wang, Jieci; Jing, Jiliang

2016-01-01

In the framework of open quantum systems, we study the dynamics of a static polarizable two-level atom interacting with a bath of fluctuating vacuum electromagnetic field and explore under which conditions the coherence of the open quantum system is unaffected by the environment. For both a single-qubit and two-qubit systems, we find that the quantum coherence cannot be protected from noise when the atom interacts with a non-boundary electromagnetic field. However, with the presence of a boundary, the dynamical conditions for the insusceptible of quantum coherence are fulfilled only when the atom is close to the boundary and is transversely polarizable. Otherwise, the quantum coherence can only be protected in some degree in other polarizable direction. -- Highlights: •We study the dynamics of a two-level atom interacting with a bath of fluctuating vacuum electromagnetic field. •For both a single and two-qubit systems, the quantum coherence cannot be protected from noise without a boundary. •The insusceptible of the quantum coherence can be fulfilled only when the atom is close to the boundary and is transversely polarizable. •Otherwise, the quantum coherence can only be protected in some degree in other polarizable direction.

International cooperation in the field of reprocessing

International Nuclear Information System (INIS)

Busekist, O. von

1983-01-01

Following a definition of the concept of international cooperation, this paper discusses existing and possible legal and institutional arrangements in the reprocessing field, with particular reference to the legal framework set up for the European Company for the Chemical Processing of Irradiated Fuels (Eurochemic). (NEA) [fr

Incentives and cooperation in firms: Field evidence

OpenAIRE

Berger, Johannes; Herbertz, Claus; Sliwka, Dirk

2011-01-01

We empirically investigate the impact of incentive scheme structure on the degree of cooperation in firms using a unique and representative data set. Combining employee survey data with detailed firm level information on the relative importance of individual, team, and company performance for compensation, we find a significant positive relation between the intensity of team incentives and several survey measures of cooperation. Moreover, higher powered team incentives are associated with low...

Mean-field lattice trees

NARCIS (Netherlands)

Borgs, C.; Chayes, J.T.; Hofstad, van der R.W.; Slade, G.

1999-01-01

We introduce a mean-field model of lattice trees based on embeddings into d of abstract trees having a critical Poisson offspring distribution. This model provides a combinatorial interpretation for the self-consistent mean-field model introduced previously by Derbez and Slade [9], and provides an

Future of international cooperative activity for graduate school education in nuclear field

International Nuclear Information System (INIS)

Obara, Toru

2008-01-01

Further improvement of graduate school education in nuclear field is one of the important issues in universities in nuclear field. The COE-INES program has performed international cooperative activities for graduate school education with foreign universities in nuclear field. There are a lot of possibilities in international cooperation with foreign universities for graduate school education. The use of Internet can be a strong tool for the activities. (author)

Mean field games for cognitive radio networks

KAUST Repository

Tembine, Hamidou

2012-06-01

In this paper we study mobility effect and power saving in cognitive radio networks using mean field games. We consider two types of users: primary and secondary users. When active, each secondary transmitter-receiver uses carrier sensing and is subject to long-term energy constraint. We formulate the interaction between primary user and large number of secondary users as an hierarchical mean field game. In contrast to the classical large-scale approaches based on stochastic geometry, percolation theory and large random matrices, the proposed mean field framework allows one to describe the evolution of the density distribution and the associated performance metrics using coupled partial differential equations. We provide explicit formulas and algorithmic power management for both primary and secondary users. A complete characterization of the optimal distribution of energy and probability of success is given.

Short-range correlations in an extended time-dependent mean-field theory

International Nuclear Information System (INIS)

Madler, P.

1982-01-01

A generalization is performed of the time-dependent mean-field theory by an explicit inclusion of strong short-range correlations on a level of microscopic reversibility relating them to realistic nucleon-nucleon forces. Invoking a least action principle for correlated trial wave functions, equations of motion for the correlation functions and the single-particle model wave function are derived in lowest order of the FAHT cluster expansion. Higher order effects as well as long-range correlations are consider only to the extent to which they contribute to the mean field via a readjusted phenomenological effective two-body interaction. The corresponding correlated stationary problem is investigated and appropriate initial conditions to describe a heavy ion reaction are proposed. The singleparticle density matrix is evaluated

Development of mean field theories in nuclear physics and in desordered media

International Nuclear Information System (INIS)

Orland, Henri.

1981-04-01

This work, in two parts, deals with the development of mean field theories in nuclear physics (nuclei in balance and collisions of heavy ions) as well as in disordered media. In the first part, two different ways of tackling the problem of developments around mean field theories are explained. Possessing an approach wave function for the system, the natural idea for including the correlations is to develop the exact wave function of the system around the mean field wave function. The first two chapters show two different ways of dealing with this problem: the perturbative approach - Hartree-Fock equations with two body collisions and functional methods. In the second part: mean field theory for spin glasses. The problem for spin glasses is to construct a physically acceptable mean field theory. The importance of this problem in statistical mechanics is linked to the fact that the mean field theory provides a qualitative description of the low temperature phase and is the starting point needed for using more sophisticated methods (renormalization group). Two approaches to this problem are presented, one based on the Sherrington-Kirkpatrick model and the other based on a model of spins with purely local disorder and competitive interaction between the spins [fr

Mean-Field Games for Marriage

Science.gov (United States)

Bauso, Dario; Dia, Ben Mansour; Djehiche, Boualem; Tembine, Hamidou; Tempone, Raul

2014-01-01

This article examines mean-field games for marriage. The results support the argument that optimizing the long-term well-being through effort and social feeling state distribution (mean-field) will help to stabilize marriage. However, if the cost of effort is very high, the couple fluctuates in a bad feeling state or the marriage breaks down. We then examine the influence of society on a couple using mean-field sentimental games. We show that, in mean-field equilibrium, the optimal effort is always higher than the one-shot optimal effort. We illustrate numerically the influence of the couple’s network on their feeling states and their well-being. PMID:24804835

Mean-field games for marriage.

Directory of Open Access Journals (Sweden)

Dario Bauso

Full Text Available This article examines mean-field games for marriage. The results support the argument that optimizing the long-term well-being through effort and social feeling state distribution (mean-field will help to stabilize marriage. However, if the cost of effort is very high, the couple fluctuates in a bad feeling state or the marriage breaks down. We then examine the influence of society on a couple using mean-field sentimental games. We show that, in mean-field equilibrium, the optimal effort is always higher than the one-shot optimal effort. We illustrate numerically the influence of the couple's network on their feeling states and their well-being.

Development of Work Verification System for Cooperation between MCR Operators and Field Workers in Nuclear Power Plants

International Nuclear Information System (INIS)

Lee, Seung Min; Seong, Poong Hyun; Lee, Hyun Chul

2014-01-01

In this work, as an application of digital devices to NPPs, a cooperation support system to aid communication between MCR operators and field workers in Nuclear Power Plants (NPPs), NUclear COoperation Support and MObile document System (Nu-COSMOS), is suggested. It is not easy for MCR operators to estimate whether field workers conduct their work correctly because MCR operators cannot monitor field workers at a real time, and records on paper procedure written by field workers do not contain the detailed information about work process and results. Thus, for safety operation without any events induced by misunderstand and miscommunication between MCR operators and field workers, the Nu-COSMOS is developed and it will be useful from the supporting cooperation point of view. To support the cooperation between MCR operators and field workers in NPPs, the cooperation support and mobile documentation system Nu-COSMOS is suggested in this work. To improve usability and applicability of the suggested system, the results of using existed digital device based support systems were analyzed. Through the analysis, the disincentive elements of using digital device-based developments and the recommendations for developing new mobile based system were derived. Based on derived recommendations, two sub systems, the mobile device based in-formation storing system and the large screen based information sharing system were suggested. The usability of the suggested system will be conducted by a survey with questionnaires. Field workers and operators, and nuclear-related person who had experiences as an operator, graduate students affiliated in nuclear engineering department will use and test the functions of the suggested system. It is expected that the mobile based information storing system can reduce the field workers' work load and enhance the understanding of MCR operators about field operators work process by monitoring all work results and work processes stored in devices

Development of Work Verification System for Cooperation between MCR Operators and Field Workers in Nuclear Power Plants

Energy Technology Data Exchange (ETDEWEB)

Lee, Seung Min; Seong, Poong Hyun [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of); Lee, Hyun Chul [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2014-05-15

In this work, as an application of digital devices to NPPs, a cooperation support system to aid communication between MCR operators and field workers in Nuclear Power Plants (NPPs), NUclear COoperation Support and MObile document System (Nu-COSMOS), is suggested. It is not easy for MCR operators to estimate whether field workers conduct their work correctly because MCR operators cannot monitor field workers at a real time, and records on paper procedure written by field workers do not contain the detailed information about work process and results. Thus, for safety operation without any events induced by misunderstand and miscommunication between MCR operators and field workers, the Nu-COSMOS is developed and it will be useful from the supporting cooperation point of view. To support the cooperation between MCR operators and field workers in NPPs, the cooperation support and mobile documentation system Nu-COSMOS is suggested in this work. To improve usability and applicability of the suggested system, the results of using existed digital device based support systems were analyzed. Through the analysis, the disincentive elements of using digital device-based developments and the recommendations for developing new mobile based system were derived. Based on derived recommendations, two sub systems, the mobile device based in-formation storing system and the large screen based information sharing system were suggested. The usability of the suggested system will be conducted by a survey with questionnaires. Field workers and operators, and nuclear-related person who had experiences as an operator, graduate students affiliated in nuclear engineering department will use and test the functions of the suggested system. It is expected that the mobile based information storing system can reduce the field workers' work load and enhance the understanding of MCR operators about field operators work process by monitoring all work results and work processes stored in devices.

Mean-field games for marriage

KAUST Repository

Bauso, Dario

2014-05-07

This article examines mean-field games for marriage. The results support the argument that optimizing the long-term well-being through effort and social feeling state distribution (mean-field) will help to stabilize marriage. However, if the cost of effort is very high, the couple fluctuates in a bad feeling state or the marriage breaks down. We then examine the influence of society on a couple using mean-field sentimental games. We show that, in mean-field equilibrium, the optimal effort is always higher than the one-shot optimal effort. We illustrate numerically the influence of the couple\\'s network on their feeling states and their well-being. © 2014 Bauso et al.

Mean-field games for marriage

KAUST Repository

Bauso, Dario; Dia, Ben Mansour; Djehiche, Boualem; Tembine, Hamidou; Tempone, Raul

2014-01-01

This article examines mean-field games for marriage. The results support the argument that optimizing the long-term well-being through effort and social feeling state distribution (mean-field) will help to stabilize marriage. However, if the cost of effort is very high, the couple fluctuates in a bad feeling state or the marriage breaks down. We then examine the influence of society on a couple using mean-field sentimental games. We show that, in mean-field equilibrium, the optimal effort is always higher than the one-shot optimal effort. We illustrate numerically the influence of the couple's network on their feeling states and their well-being. © 2014 Bauso et al.

Mutually cooperative epidemics on power-law networks

Science.gov (United States)

Cui, Peng-Bi; Colaiori, Francesca; Castellano, Claudio

2017-08-01

The spread of an infectious disease can, in some cases, promote the propagation of other pathogens favoring violent outbreaks, which cause a discontinuous transition to an endemic state. The topology of the contact network plays a crucial role in these cooperative dynamics. We consider a susceptible-infected-removed-type model with two mutually cooperative pathogens: An individual already infected with one disease has an increased probability of getting infected by the other. We present a heterogeneous mean-field theoretical approach to the coinfection dynamics on generic uncorrelated power-law degree-distributed networks and validate its results by means of numerical simulations. We show that, when the second moment of the degree distribution is finite, the epidemic transition is continuous for low cooperativity, while it is discontinuous when cooperativity is sufficiently high. For scale-free networks, i.e., topologies with diverging second moment, the transition is instead always continuous. In this way we clarify the effect of heterogeneity and system size on the nature of the transition, and we validate the physical interpretation about the origin of the discontinuity.

Report of cooperative research programs in the field of ion-beam breeding between Japan Atomic Energy Agency and Malaysian Nuclear Agency (Bilateral cooperative research)

International Nuclear Information System (INIS)

Ahmad, Zaiton; Oono, Yutaka

2016-03-01

This report summarizes Bilateral Cooperative Research between Japan Atomic Energy Agency and Malaysian Nuclear Agency (a representative of the Government of Malaysia) implemented from 2002 to 2012 under 'THE IMPLEMENTING ARRANGEMENT BETWEEN THE GOVERNMENT OF MALAYSIA AND THE JAPAN ATOMIC ENERGY AGENCY ON THE RESEARCH COOPERATION IN THE FIELD OF RADIATION PROCESSING'. The research activities in two Cooperative Research Programs, 'Mutation Induction of Orchid Plants by Ion Beams' and 'Generating New Ornamental Plant Varieties Using Ion Beams' performed 2002-2007 and 2007-2012, respectively, are contained. The lists of steering committee meetings, irradiation experiments, and publications/presentations of each program are also attached in the Appendixes. (author)

COOPERATION IN THE FIELD OF ECONOMICS, OF SCIENCE AND MEDICINE IN EUROPE

Directory of Open Access Journals (Sweden)

Norina-Consuela FORNA

2015-07-01

Full Text Available The issue of medical cooperation raises many questions current and controversial, which are the focus of interest in socio-political and legal, such as debates on instruments to combat the high costs, the public health system, legislation aimed at ensuring health, tobacco consumption, alcohol, obesity and others. Public health legislation deals with the framework conditions, legal and social aspects of public health, protection and deployment the law of public health on tobacco. The aim of this study is to identify the degree to which economic freedom correlates with indicators of development, health and economic cooperation in medicine field. In this regard, we consider useful to investigate how the correlation indicators of policy Health – 2020 with global and European economic development. Research methods are located in estimating the degree of international cooperation in the medicine field through statistical methods, comparison, graphics, deduction or induction.The results allow to formulate a whole picture regarding international cooperation in the field of medicine, combating different diseases but human vices as obesity, tobacco use, alcohol etc. Facilitation of cooperation in research and innovation is the key to bridging the gap between research and demand in different countries and regions.

International co-operation in the nuclear field. Europe and OCDE countries

International Nuclear Information System (INIS)

Strohl, P.

1981-05-01

This report highlights the political factors underlying nuclear cooperation in the European context. It analyses the institutional structure for such cooperation and describes the different vocations of international organisations in the nuclear field (NEA, IAEA, Euratom). Finally the report gives concrete examples of international nuclear cooperation, with an emphasis on its legal aspects. (NEA) []Le present expose fait ressortir les facteurs politiques de la cooperation nucleaire notamment dans le contexte europeen. Il analyse la structure institutionnelle de cette cooperation et evoque les differentes vocations des organismes internationaux dans le domaine nucleaire (AEN, AIEA, Euratom). Il donne enfin des exemples concrets en mettant l'accent sur ses aspects juridiques

Two interacting spins in external fields. Four-level systems

Energy Technology Data Exchange (ETDEWEB)

Bagrov, V.G.; Baldiotti, M.C.; Gitman, D.M. [Instituto de Fisica, Universidade de Sao Paulo, Caixa Postal 66318-CEP, 05315-970 Sao Paulo, S.P. (Brazil); Levin, A.D. [Dexter Research Center (United States)

2007-04-15

In the present article, we consider the so-called two-spin equation that describes four-level quantum systems. Recently, these systems attract attention due to their relation to the problem of quantum computation. We study general properties of the two-spin equation and show that the problem for certain external backgrounds can be identified with the problem of one spin in an appropriate background. This allows one to generate a number of exact solutions for two-spin equations on the basis of already known exact solutions of the one-spin equation. Besides, we present some exact solutions for the two-spin equation with an external background different for each spin but having the same direction. We study the eigenvalue problem for a time-independent spin interaction and a time-independent external background. A possible analogue of the Rabi problem for the two-spin equation is defined. We present its exact solution and demonstrate the existence of magnetic resonances in two specific frequencies, one of them coinciding with the Rabi frequency, and the other depending on the rotating field magnitude. The resonance that corresponds to the second frequency is suppressed with respect to the first one. (Abstract Copyright [2007], Wiley Periodicals, Inc.)

[Political and organizational-legal frameworks for cooperation between countries of the Asia-Pacific region in the field of military medicine].

Science.gov (United States)

Kholikov, I V; Dmitrakovich, D V

2014-12-01

A framework for cooperation in the field of military medicine in the Asia-Pacific region is considered. Expert Working Group on Military Medicine in cooperation with the Association of Southeast Asian dialogue partners (including Russia) was formed to discuss the most important issues in the field of military medicine, to share practical experience of military physicians, standardization and unification of medical equipment, medicines, levels and standards of medical services and other issues in order to enhance cooperation of military medical services of the participating countries. From 2014 to 2016, the Russian Federation and the Kingdom of Thailand are co-chairs of the expert group.

Mean Field Type Control with Congestion

Energy Technology Data Exchange (ETDEWEB)

Achdou, Yves, E-mail: achdou@ljll.univ-paris-diderot.fr; Laurière, Mathieu [Univ. Paris Diderot, Sorbonne Paris Cité, Laboratoire Jacques-Louis Lions, UMR 7598, UPMC, CNRS (France)

2016-06-15

We analyze some systems of partial differential equations arising in the theory of mean field type control with congestion effects. We look for weak solutions. Our main result is the existence and uniqueness of suitably defined weak solutions, which are characterized as the optima of two optimal control problems in duality.

Extended Deterministic Mean-Field Games

KAUST Repository

Gomes, Diogo A.

2016-04-21

In this paper, we consider mean-field games where the interaction of each player with the mean field takes into account not only the states of the players but also their collective behavior. To do so, we develop a random variable framework that is particularly convenient for these problems. We prove an existence result for extended mean-field games and establish uniqueness conditions. In the last section, we consider the Master Equation and discuss properties of its solutions.

Extended Deterministic Mean-Field Games

KAUST Repository

Gomes, Diogo A.; Voskanyan, Vardan K.

2016-01-01

In this paper, we consider mean-field games where the interaction of each player with the mean field takes into account not only the states of the players but also their collective behavior. To do so, we develop a random variable framework that is particularly convenient for these problems. We prove an existence result for extended mean-field games and establish uniqueness conditions. In the last section, we consider the Master Equation and discuss properties of its solutions.

Mean-field theory of active electrolytes: Dynamic adsorption and overscreening

Science.gov (United States)

Frydel, Derek; Podgornik, Rudolf

2018-05-01

We investigate active electrolytes within the mean-field level of description. The focus is on how the double-layer structure of passive, thermalized charges is affected by active dynamics of constituting ions. One feature of active dynamics is that particles adhere to hard surfaces, regardless of chemical properties of a surface and specifically in complete absence of any chemisorption or physisorption. To carry out the mean-field analysis of the system that is out of equilibrium, we develop the "mean-field simulation" technique, where the simulated system consists of charged parallel sheets moving on a line and obeying active dynamics, with the interaction strength rescaled by the number of sheets. The mean-field limit becomes exact in the limit of an infinite number of movable sheets.

Study of Landau spectrum for a two-dimensional random magnetic field

International Nuclear Information System (INIS)

Furtlehner, C.

1997-01-01

This thesis deals with the two-dimensional problem of a charged particle coupled to a random magnetic field. Various situations are considered, according to the relative importance of the mean value of field and random component. The last one is conceived as a distribution of magnetic impurities (punctual vortex), having various statistical properties (local or non-local correlations, Poisson distribution, etc). The study of this system has led to two distinct situations: - the case of the charged particle feeling the influence of mean field that manifests its presence in the spectrum of broadened Landau levels; - the disordered situation in which the spectrum can be distinguished from the free one only by a low energy Lifshits behaviour. Additional properties are occurring in the limit of 'strong' mean field, namely a non-conventional low energy behaviour (in contrast to Lifshits behaviour) which was interpreted in terms of localized states. (author)

Mean field games for cognitive radio networks

KAUST Repository

Tembine, Hamidou; Tempone, Raul; Vilanova, Pedro

2012-01-01

In this paper we study mobility effect and power saving in cognitive radio networks using mean field games. We consider two types of users: primary and secondary users. When active, each secondary transmitter-receiver uses carrier sensing

Academic Procrastination and the Performance of Graduate-Level Cooperative Groups in Research Methods Courses

Science.gov (United States)

Jiao, Qun G.; DaRos-Voseles, Denise A.; Collins, Kathleen M. T.; Onwuegbuzie, Anthony J.

2011-01-01

This study examined the extent to which academic procrastination predicted the performance of cooperative groups in graduate-level research methods courses. A total of 28 groups was examined (n = 83 students), ranging in size from 2 to 5 (M = 2.96, SD = 1.10). Multiple regression analyses revealed that neither within-group mean nor within-group…

Promotion of cooperation induced by two-sided players in prisoner's dilemma game

Science.gov (United States)

Su, Zhen; Li, Lixiang; Xiao, Jinghua; Podobnik, B.; Stanley, H. Eugene

2018-01-01

We examine how real-world individuals and companies can either reach an agreement or fail to reach an agreement after several stages of negotiation. We use a modified prisoner's dilemma game with two-sided players who can either cooperate or not cooperate with their neighbors. We find that the presence of even a small number of these two-sided players substantially promotes the cooperation because, unlike the rock-paper-scissors scenario, when the cooperators change to the non-cooperators to gain a payoff, they can turn to the two-sided players and continue negotiating. We find that the network structure influences the spread of strategies. Lattice and regular-random (RR) networks benefit the spread of both non-cooperation and two-sided strategies, but scale-free (SF) networks stop both strategies. We also find that the Erdös-R e ´ nyi (ER) network promotes the two-sided strategy and blocks the spread of non-cooperation. As the ER network density decreases, and the network degree is lowered the lifetime of non-cooperators increases. Our results expand our understanding of the role played by the two-sided strategy in the growth of the cooperative behavior in networks.

UNIVERSITY INTERNATIONAL COOPERATION AS A MEANS FOR REGIONAL INTEGRATION AND DEVELOPMENT

Directory of Open Access Journals (Sweden)

Viktoriia DONCHENKO

2015-10-01

Full Text Available Programs of international cooperation in higher education claim to promote peace and intercultural understanding, contribute to development of efficient human resources as well as research and innovation. For centuries, universities were centers of progress that ensure community’s development. Processes of globalization, internationalization, rapid development of information technology transform the mission of university, challenging modern universities to join forces to meet growing needs of knowledge society. The European Higher Education Area is continuously working to reduce mismatch of skills between the workforce and labor market. International cooperation in education has fundamental potential for reducing economic disparity. Ukrainian government views higher education as a means of growth and development and considers international activity pivotal in responding to global and regional change and achieving world quality standards of education. The aim of this paper is to explore potential of international cooperation in higher education in globalized world by examining selected international projects and their outcomes.

Technical cooperation on government base with developing countries in the field of atomic energy

International Nuclear Information System (INIS)

Hamabe, Yutaka

1984-01-01

Since the summer of the last year, the problems in the relation with developing countries have been actively discussed in the Atomic Energy Commission, Japan Atomic Industrial Forum Inc., and the Ministry of International Trade and Industry. As the background of this tendency, it is pointed out that Japanese nuclear industry has grown up to the level comparable with European and American counterparts and capable of advancing into the world market as the exporter of nuclear facilities, on the other hand, that Asian countries expect Japanese technical and economical power also in the field of atomic energy. In this report, the technical cooperation of the IAEA on funds, the dispatch of specialists, the supply of materials and training, the technical cooperation of Japanese International Cooperation Agency on the acceptance of trainees, the dispatch of specialists and others, and the fundamental way of thinking about the technical cooperation on government base are reported. It is very important to grasp the true needs of a partner country when a project is selected. In the cooperation, the effort of self-help by a developing country must be the major premise. (Kako, I.)

Neutron fraction and neutrino mean free path predictions in relativistic mean field models

International Nuclear Information System (INIS)

Hutauruk, P.T.P.; Williams, C.K.; Sulaksono, A.; Mart, T.

2004-01-01

The equation of state (EOS) of dense matter and neutrino mean free path (NMFP) in a neutron star have been studied by using relativistic mean field models motivated by effective field theory. It is found that the models predict too large proton fractions, although one of the models (G2) predicts an acceptable EOS. This is caused by the isovector terms. Except G2, the other two models predict anomalous NMFP's. In order to minimize the anomaly, besides an acceptable EOS, a large M* is favorable. A model with large M* retains the regularity in the NMFP even for a small neutron fraction

Mean-field approximation for spacing distribution functions in classical systems

Science.gov (United States)

González, Diego Luis; Pimpinelli, Alberto; Einstein, T. L.

2012-01-01

We propose a mean-field method to calculate approximately the spacing distribution functions p(n)(s) in one-dimensional classical many-particle systems. We compare our method with two other commonly used methods, the independent interval approximation and the extended Wigner surmise. In our mean-field approach, p(n)(s) is calculated from a set of Langevin equations, which are decoupled by using a mean-field approximation. We find that in spite of its simplicity, the mean-field approximation provides good results in several systems. We offer many examples illustrating that the three previously mentioned methods give a reasonable description of the statistical behavior of the system. The physical interpretation of each method is also discussed.

Excitons and Cooper pairs two composite bosons in many-body physics

CERN Document Server

Combescot, Monique

2015-01-01

This book bridges a gap between two major communities of Condensed Matter Physics, Semiconductors and Superconductors, that have thrived independently. Through an original perspective that their key particles, excitons and Cooper pairs, are composite bosons, the authors raise fundamental questions of current interest: how does the Pauli exclusion principle wield its power on the fermionic components of bosonic particles at a microscopic level and how this affects the macroscopic physics? What can we learn from Wannier and Frenkel excitons and from Cooper pairs that helps us understand "bosonic condensation" of composite bosons and its difference from Bose-Einstein condensation of elementary bosons? The authors start from solid mathematical and physical foundation to derive excitons and Cooper pairs. They further introduce Shiva diagrams as a graphic support to grasp the many-body physics induced by fermion exchange - a novel mechanism not visualized by standard Feynman diagrams. Advanced undergraduate or grad...

Quantum averaging and resonances: two-level atom in a one-mode classical laser field

Directory of Open Access Journals (Sweden)

M. Amniat-Talab

2007-06-01

Full Text Available   We use a nonperturbative method based on quantum averaging and an adapted from of resonant transformations to treat the resonances of the Hamiltonian of a two-level atom interacting with a one-mode classical field in Floquet formalism. We illustrate this method by extraction of effective Hamiltonians of the system in two regimes of weak and strong coupling. The results obtained in the strong-coupling regime, are valid in the whole range of the coupling constant for the one-photon zero-field resonance.

Technological transfers and cooperation in the field of climatic change

International Nuclear Information System (INIS)

Riedacker, A.

2002-01-01

Fighting against climatic changes and adapting to them is a necessary condition to achieve sustainable development. The ultimate goal of the Framework Convention on Climate Change signed in Rio in 1992, and specified in article 2, is to stabilize the concentrations of greenhouse gases at a level that does not threaten climatic systems and allows ecosystems to adapt to climatic change, ensures that food production is not in danger and that sustainable development be achieved. A radical paradigm change is required, and in particular the adoption of new technologies. First, the new technologies must assist in limiting the emissions of greenhouse gases, both in industrialized and developing countries, and to adapt to the climatic changes. The author is of the opinion that technology transfers represent a means to address the issue of climatic change. The concentration of carbon dioxide in the atmosphere continues to increase since the advent of the industrial revolution. It seems dubious that we will be able to stabilize the climate to its actual level, therefore we must learn to adapt while continuing to reduce the emissions of greenhouse gases. The author then examines the technological cooperation since the adoption of the Marrakech Accords in 2001. The next section deals with technological cooperation between francophone cities of the north and francophone cities of the south. The author concludes by placing the emphasis on the importance of regular meetings and the implementation of specialized networks, such as the network on the technology of arid regions, in an effort to assist the technological cooperation north-south and south-south in the fight against climatic change. 2 figs

Virtual-site correlation mean field approach to criticality in spin systems

International Nuclear Information System (INIS)

Sen, Aditi; Sen, Ujjwal

2013-01-01

We propose a virtual-site correlation mean field theory for dealing with interacting many-body systems. It involves a coarse-graining technique that terminates a step before the mean field theory: While mean field theory deals with only single-body physical parameters, the virtual-site correlation mean field theory deals with single- as well as two-body ones, and involves a virtual site for every interaction term in the Hamiltonian. We generalize the theory to a cluster virtual-site correlation mean field, that works with a fundamental unit of the lattice of the many-body system. We apply these methods to interacting Ising spin systems in several lattice geometries and dimensions, and show that the predictions of the onset of criticality of these models are generally much better in the proposed theories as compared to the corresponding ones in mean field theories

Stochastic mean-field dynamics for fermions in the weak coupling limit

International Nuclear Information System (INIS)

Lacroix, D.

2005-09-01

Assuming that the effect of the residual interaction beyond mean-field is weak and can be treated as a statistical ensemble of two-body interactions, a Markovian quantum jump theory is developed for fermionic systems. In this theory, jumps occur between many-body densities formed of pairs of states D |Φ a > b | / b | |Φ a > where |Φ a > and |Φ b > are anti-symmetrized products of single-particle states. The underlying Stochastic Mean-Field (SMF) theory is discussed and applied to the monopole vibration of a spherical 40 Ca nucleus under the influence of a statistical ensemble of two-body contact interactions. In this example, the mean-field evolution of one-body observables is recovered by averaging over different stochastic trajectories while fluctuations beyond mean-field are observed. Finally, the nature of the fluctuations is discussed. (author)

Lane-Level Vehicle Trajectory Reckoning for Cooperative Vehicle-Infrastructure System

Directory of Open Access Journals (Sweden)

Yinsong Wang

2012-01-01

Full Text Available This paper presents a lane-level positioning method by trajectory reckoning without Global Positioning System (GPS equipment in the environment of Cooperative Vehicle-Infrastructure System (CVIS. Firstly, the accuracy requirements of vehicle position in CVIS applications and the applicability of GPS positioning methods were analyzed. Then, a trajectory reckoning method based on speed and steering data from vehicle’s Control Area Network (CAN and roadside calibration facilities was proposed, which consists of three critical models, including real-time estimation of steering angle and vehicle direction, vehicle movement reckoning, and wireless calibration. Finally, the proposed method was validated through simulation and field tests under a variety of traffic conditions. Results show that the accuracy of the reckoned vehicle position can reach the lane level and match the requirements of common CVIS applications.

Constrained deterministic leader-follower mean field control

NARCIS (Netherlands)

Möller, L.; Gentile, B.; Parise, F.; Grammatico, S.; Lygeros, J.

2016-01-01

We consider a mean field game among a large population of noncooperative agents divided into two categories: leaders and followers. Each agent is subject to heterogeneous convex constraints and minimizes a quadratic cost function; the cost of each leader is affected by the leaders' aggregate

The mean magnetic field of the sun - Method of observation and relation to the interplanetary magnetic field

Science.gov (United States)

Scherrer, P. H.; Wilcox, J. M.; Kotov, V.; Severnyi, A. B.; Howard, R.

1977-01-01

The mean solar magnetic field as measured in integrated light has been observed since 1968. Since 1970 it has been observed both at Hale Observatories and at the Crimean Astrophysical Observatory. The observing procedures at both observatories and their implications for mean field measurements are discussed. A comparison of the two sets of daily observations shows that similar results are obtained at both observatories. A comparison of the mean field with the interplanetary magnetic polarity shows that the IMF sector structure has the same pattern as the mean field polarity.

Orbital effect of the magnetic field in dynamical mean-field theory

Science.gov (United States)

Acheche, S.; Arsenault, L.-F.; Tremblay, A.-M. S.

2017-12-01

The availability of large magnetic fields at international facilities and of simulated magnetic fields that can reach the flux-quantum-per-unit-area level in cold atoms calls for systematic studies of orbital effects of the magnetic field on the self-energy of interacting systems. Here we demonstrate theoretically that orbital effects of magnetic fields can be treated within single-site dynamical mean-field theory with a translationally invariant quantum impurity problem. As an example, we study the one-band Hubbard model on the square lattice using iterated perturbation theory as an impurity solver. We recover the expected quantum oscillations in the scattering rate, and we show that the magnetic fields allow the interaction-induced effective mass to be measured through the single-particle density of states accessible in tunneling experiments. The orbital effect of magnetic fields on scattering becomes particularly important in the Hofstadter butterfly regime.

Cooperativeness and competitiveness as two distinct constructs: validating the Cooperative and Competitive Personality Scale in a social dilemma context.

Science.gov (United States)

Lu, Su; Au, Wing-Tung; Jiang, Feng; Xie, Xiaofei; Yam, Paton

2013-01-01

The present research validated the construct and criterion validities of the Cooperative and Competitive Personality Scale (CCPS) in a social dilemma context. The results from three studies supported the notion that cooperativeness and competitiveness are two independent dimensions, challenging the traditional view that they are two ends of a single continuum. First, confirmatory factor analyses revealed that a two-factor structure fit the data significantly better than a one-factor structure. Moreover, cooperativeness and competitiveness were either not significantly correlated (Studies 1 and 3) or only moderately positively correlated (Study 2). Second, cooperativeness and competitiveness were differentially associated with Schwartz's Personal Values. These results further supported the idea that cooperativeness and competitiveness are two distinct constructs. Specifically, the individuals who were highly cooperative emphasized self-transcendent values (i.e., universalism and benevolence) more, whereas the individuals who were highly competitive emphasized self-enhancement values (i.e., power and achievement) more. Finally, the CCPS, which adheres to the trait perspective of personality, was found to be a useful supplement to more prevalent social motive measures (i.e., social value orientation) in predicting cooperative behaviors. Specifically, in Study 2, when social value orientation was controlled for, the CCPS significantly predicted cooperative behaviors in a public goods dilemma (individuals who score higher on cooperativeness scale contributed more to the public goods). In Study 3, when social value orientation was controlled for, the CCPS significantly predicted cooperative behaviors in commons dilemmas (individuals who score higher on cooperativeness scale requested fewer resources from the common resource pool). The practical implications of the CCPS in conflict resolution, as well as in recruitment and selection settings, are discussed.

Stochastic mean-field dynamics for fermions in the weak coupling limit

Energy Technology Data Exchange (ETDEWEB)

Lacroix, D

2005-09-15

Assuming that the effect of the residual interaction beyond mean-field is weak and can be treated as a statistical ensemble of two-body interactions, a Markovian quantum jump theory is developed for fermionic systems. In this theory, jumps occur between many-body densities formed of pairs of states D |{phi}{sub a}> <|{phi}{sub b}| / <|{phi}{sub b} | |{phi} {sub a}> where |{phi}{sub a}> and |{phi}{sub b}> are anti-symmetrized products of single-particle states. The underlying Stochastic Mean-Field (SMF) theory is discussed and applied to the monopole vibration of a spherical {sup 40}Ca nucleus under the influence of a statistical ensemble of two-body contact interactions. In this example, the mean-field evolution of one-body observables is recovered by averaging over different stochastic trajectories while fluctuations beyond mean-field are observed. Finally, the nature of the fluctuations is discussed. (author)

Cooperative binding of transcription factors promotes bimodal gene expression response.

Directory of Open Access Journals (Sweden)

Pablo S Gutierrez

Full Text Available In the present work we extend and analyze the scope of our recently proposed stochastic model for transcriptional regulation, which considers an arbitrarily complex cis-regulatory system using only elementary reactions. Previously, we determined the role of cooperativity on the intrinsic fluctuations of gene expression for activating transcriptional switches, by means of master equation formalism and computer simulation. This model allowed us to distinguish between two cooperative binding mechanisms and, even though the mean expression levels were not affected differently by the acting mechanism, we showed that the associated fluctuations were different. In the present generalized model we include other regulatory functions in addition to those associated to an activator switch. Namely, we introduce repressive regulatory functions and two theoretical mechanisms that account for the biphasic response that some cis-regulatory systems show to the transcription factor concentration. We have also extended our previous master equation formalism in order to include protein production by stochastic translation of mRNA. Furthermore, we examine the graded/binary scenarios in the context of the interaction energy between transcription factors. In this sense, this is the first report to show that the cooperative binding of transcription factors to DNA promotes the "all-or-none" phenomenon observed in eukaryotic systems. In addition, we confirm that gene expression fluctuation levels associated with one of two cooperative binding mechanism never exceed the fluctuation levels of the other.

Study of two-proton radioactivity within the relativistic mean-field plus BCS approach

International Nuclear Information System (INIS)

Singh, D.; Saxena, G.

2012-01-01

Inspired by recent experimental studies of two-proton radioactivity in the light-medium mass region, we have employed relativistic mean-field plus state-dependent BCS approach (RMF+BCS) to study the ground state properties of selected even-Z nuclei in the region 20 ≤ Z ≤ 40. It is found that the effective potential barrier provided by the Coulomb interaction and that due to centrifugal force may cause a long delay in the decay of some of the nuclei even with small negative proton separation energy. This may cause the existence of proton-rich nuclei beyond the proton drip-line. Nuclei 38 Ti, 42 Cr, 45 Fe, 48 Ni, 55 Zn, 60 Ge, 63, 64 Se, 68 Kr, 72 Sr and 76 Zr are found to be the potential candidates for exhibiting two-proton radioactivity in the region 20 ≤ Z ≤ 40. The reliability of these predictions is further strengthened by the agreement of the calculated results for the ground state properties such as binding energy, one- and two-proton separation energy, proton and neutron radii, and deformation with the available experimental data for the entire chain of the isotopes of the nuclei in the region 20 ≤ Z ≤ 40. (author)

Mean-field magnetohydrodynamics and dynamo theory

CERN Document Server

Krause, F

2013-01-01

Mean-Field Magnetohydrodynamics and Dynamo Theory provides a systematic introduction to mean-field magnetohydrodynamics and the dynamo theory, along with the results achieved. Topics covered include turbulence and large-scale structures; general properties of the turbulent electromotive force; homogeneity, isotropy, and mirror symmetry of turbulent fields; and turbulent electromotive force in the case of non-vanishing mean flow. The turbulent electromotive force in the case of rotational mean motion is also considered. This book is comprised of 17 chapters and opens with an overview of the gen

Continuous Time Finite State Mean Field Games

International Nuclear Information System (INIS)

Gomes, Diogo A.; Mohr, Joana; Souza, Rafael Rigão

2013-01-01

In this paper we consider symmetric games where a large number of players can be in any one of d states. We derive a limiting mean field model and characterize its main properties. This mean field limit is a system of coupled ordinary differential equations with initial-terminal data. For this mean field problem we prove a trend to equilibrium theorem, that is convergence, in an appropriate limit, to stationary solutions. Then we study an N+1-player problem, which the mean field model attempts to approximate. Our main result is the convergence as N→∞ of the mean field model and an estimate of the rate of convergence. We end the paper with some further examples for potential mean field games

Continuous Time Finite State Mean Field Games

Energy Technology Data Exchange (ETDEWEB)

Gomes, Diogo A., E-mail: dgomes@math.ist.utl.pt [Instituto Superior Tecnico, Center for Mathematical Analysis, Geometry, and Dynamical Systems, Departamento de Matematica (Portugal); Mohr, Joana, E-mail: joana.mohr@ufrgs.br; Souza, Rafael Rigao, E-mail: rafars@mat.ufrgs.br [UFRGS, Instituto de Matematica (Brazil)

2013-08-01

In this paper we consider symmetric games where a large number of players can be in any one of d states. We derive a limiting mean field model and characterize its main properties. This mean field limit is a system of coupled ordinary differential equations with initial-terminal data. For this mean field problem we prove a trend to equilibrium theorem, that is convergence, in an appropriate limit, to stationary solutions. Then we study an N+1-player problem, which the mean field model attempts to approximate. Our main result is the convergence as N{yields}{infinity} of the mean field model and an estimate of the rate of convergence. We end the paper with some further examples for potential mean field games.

International Cooperation of the Republic of Croatia in the Field of Radiological and Nuclear Safety

International Nuclear Information System (INIS)

Novosel, N.

2011-01-01

International cooperation of the Republic of Croatia in the field of radiological and nuclear safety can be divided in two parts - political part, for which the Ministry of Foreign Affairs and European Integration is responsible, and technical part, for which the State Office for Radiological and Nuclear Safety is responsible. According to the Radiological and Nuclear Safety Act (OG 28/10) the State Office for Radiological and Nuclear Safety: ''coordinates technical cooperation with the International Atomic Energy Agency for all participants from the Republic of Croatia''; ''fulfils the obligations which the Republic of Croatia has assumed through international conventions and bilateral agreements concerning protection against ionising radiation, nuclear safety and the application of protective measures aimed at the non-proliferation of nuclear weapons'' and ''cooperates with international and domestic organisations and associations in the area of protection against ionising radiation and nuclear safety, and appoints its own expert representatives to take part in the work of such organisations and associations or to monitor their work''. In this paper various aspects of the technical cooperation with the International Atomic Energy Agency, as well as international conventions and bilateral agreements in the field of radiological and nuclear safety, are presented. Also, cooperation with other international organizations and associations in the area of radiological and nuclear safety, such as Nuclear Suppliers Group, the Zangger Committee, the Wassenaar Arrangement, Comprehensive Nuclear-Test-Ban Treaty Organization, Euratom and certain civil expert groups of NATO, is described. (author)

Inhibition of two-photon absorption in a three-level system with a pair of bichromatic fields

International Nuclear Information System (INIS)

Zou Jinhua; Hu Xiangming; Cheng Guangling; Li Xing; Du Dan

2005-01-01

We study two-photon absorption in a three-level ladder atomic system driven by a pair of bichromatic fields of equal frequency differences. The high-frequency component of one bichromatic field and the low-frequency component of the other are on two-photon resonance. The transition probability is calculated by employing the method of harmonic expansion and matrix inversion. Unexpectedly, when the sums of the phases of the different pairs of field components on the two-photon resonance are equal to each other, two-photon absorption is dramatically suppressed and the atomic system becomes transparent against two-photon absorption. Physically, due to dynamical Stark splitting, the two-photon transitions induced by the different pairs of field components experience different dressed states with phase difference of π. As a result, destructive interference occurs between the two pathways and leads to the inhibition of two-photon absorption

Mean field theory of dynamic phase transitions in ferromagnets

International Nuclear Information System (INIS)

Idigoras, O.; Vavassori, P.; Berger, A.

2012-01-01

We have studied the second order dynamic phase transition (DPT) of the two-dimensional kinetic Ising model by means of numerical calculations. While it is well established that the order parameter Q of the DPT is the average magnetization per external field oscillation cycle, the possible identity of the conjugate field has been addressed only recently. In this work, we demonstrate that our entire set of numerical data is fully consistent with the applied bias field H b being the conjugate field of order parameter Q. For this purpose, we have analyzed the Q(H b )-dependence and we have found that it follows the expected power law behavior with the same critical exponent as the mean field equilibrium case.

Dynamics of a quantum two-level system under the action of phase-diffusion field

Energy Technology Data Exchange (ETDEWEB)

Sobakinskaya, E.A. [Institute for Physics of Microstructures of RAS, Nizhny Novgorod, 603950 (Russian Federation); Pankratov, A.L., E-mail: alp@ipm.sci-nnov.ru [Institute for Physics of Microstructures of RAS, Nizhny Novgorod, 603950 (Russian Federation); Vaks, V.L. [Institute for Physics of Microstructures of RAS, Nizhny Novgorod, 603950 (Russian Federation)

2012-01-09

We study a behavior of quantum two-level system, interacting with noisy phase-diffusion field. The dynamics is shown to split into two regimes, determined by the coherence time of the phase-diffusion field. For both regimes we present a model of quantum system behavior and discuss possible applications of the obtained effect for spectroscopy. In particular, the obtained analytical formula for the macroscopic polarization demonstrates that the phase-diffusion field does not affect the absorption line shape, which opens up an intriguing possibility of noisy spectroscopy, based on broadband sources with Lorentzian line shape. -- Highlights: ► We study dynamics of quantum system interacting with noisy phase-diffusion field. ► At short times the phase-diffusion field induces polarization in the quantum system. ► At long times the noise leads to polarization decay and heating of a quantum system. ► Simple model of interaction is derived. ► Application of the described effects for spectroscopy is discussed.

From the lab to the field: Cooperation among fishermen

NARCIS (Netherlands)

J.T.R. Stoop (Jan); C. Noussair (Charles); D.P. van Soest (Daan)

2012-01-01

textabstractWe conduct a field experiment to measure cooperation among groups of recreational fishermen at a privately owned fishing facility. Group earnings are greater when group members catch fewer fish. Consistent with classical economic theory, though in contrast to prior results from

Continuous time finite state mean field games

KAUST Repository

Gomes, Diogo A.; Mohr, Joana; Souza, Rafael Rigã o

2013-01-01

In this paper we consider symmetric games where a large number of players can be in any one of d states. We derive a limiting mean field model and characterize its main properties. This mean field limit is a system of coupled ordinary differential equations with initial-terminal data. For this mean field problem we prove a trend to equilibrium theorem, that is convergence, in an appropriate limit, to stationary solutions. Then we study an N+1-player problem, which the mean field model attempts to approximate. Our main result is the convergence as N→∞ of the mean field model and an estimate of the rate of convergence. We end the paper with some further examples for potential mean field games. © 2013 Springer Science+Business Media New York.

Continuous time finite state mean field games

KAUST Repository

Gomes, Diogo A.

2013-04-23

In this paper we consider symmetric games where a large number of players can be in any one of d states. We derive a limiting mean field model and characterize its main properties. This mean field limit is a system of coupled ordinary differential equations with initial-terminal data. For this mean field problem we prove a trend to equilibrium theorem, that is convergence, in an appropriate limit, to stationary solutions. Then we study an N+1-player problem, which the mean field model attempts to approximate. Our main result is the convergence as N→∞ of the mean field model and an estimate of the rate of convergence. We end the paper with some further examples for potential mean field games. © 2013 Springer Science+Business Media New York.

Mean field dynamics of networks of delay-coupled noisy excitable units

Energy Technology Data Exchange (ETDEWEB)

Franović, Igor, E-mail: franovic@ipb.ac.rs [Scientific Computing Laboratory, Institute of Physics Belgrade, University of Belgrade, Pregrevica 118, 11080 Belgrade (Serbia); Todorović, Kristina; Burić, Nikola [Department of Physics and Mathematics, Faculty of Pharmacy, University of Belgrade, Vojvode Stepe 450, Belgrade (Serbia); Vasović, Nebojša [Department of Applied Mathematics, Faculty of Mining and Geology, University of Belgrade, PO Box 162, Belgrade (Serbia)

2016-06-08

We use the mean-field approach to analyze the collective dynamics in macroscopic networks of stochastic Fitzhugh-Nagumo units with delayed couplings. The conditions for validity of the two main approximations behind the model, called the Gaussian approximation and the Quasi-independence approximation, are examined. It is shown that the dynamics of the mean-field model may indicate in a self-consistent fashion the parameter domains where the Quasi-independence approximation fails. Apart from a network of globally coupled units, we also consider the paradigmatic setup of two interacting assemblies to demonstrate how our framework may be extended to hierarchical and modular networks. In both cases, the mean-field model can be used to qualitatively analyze the stability of the system, as well as the scenarios for the onset and the suppression of the collective mode. In quantitative terms, the mean-field model is capable of predicting the average oscillation frequency corresponding to the global variables of the exact system.

Chern-Simons field theory of two-dimensional electrons in the lowest Landau level

International Nuclear Information System (INIS)

Zhang, L.

1996-01-01

We propose a fermion Chern-Simons field theory describing two-dimensional electrons in the lowest Landau level. This theory is constructed with a complete set of states, and the lowest-Landau-level constraint is enforced through a δ functional described by an auxiliary field λ. Unlike the field theory constructed directly with the states in the lowest Landau level, this theory allows one, utilizing the physical picture of open-quote open-quote composite fermion,close-quote close-quote to study the fractional quantum Hall states by mapping them onto certain integer quantum Hall states; but, unlike its application in the unconstrained theory, such a mapping is sensible only when interactions between electrons are present. An open-quote open-quote effective mass,close-quote close-quote which characterizes the scale of low energy excitations in the fractional quantum Hall systems, emerges naturally from our theory. We study a Gaussian effective theory and interpret physically the dressed stationary point equation for λ as an equation for the open-quote open-quote mass renormalization close-quote close-quote of composite fermions. copyright 1996 The American Physical Society

Probabilistic theory of mean field games with applications

CERN Document Server

Carmona, René

2018-01-01

This two-volume book offers a comprehensive treatment of the probabilistic approach to mean field game models and their applications. The book is self-contained in nature and includes original material and applications with explicit examples throughout, including numerical solutions. Volume I of the book is entirely devoted to the theory of mean field games without a common noise. The first half of the volume provides a self-contained introduction to mean field games, starting from concrete illustrations of games with a finite number of players, and ending with ready-for-use solvability results. Readers are provided with the tools necessary for the solution of forward-backward stochastic differential equations of the McKean-Vlasov type at the core of the probabilistic approach. The second half of this volume focuses on the main principles of analysis on the Wasserstein space. It includes Lions' approach to the Wasserstein differential calculus, and the applications of its results to the analysis of stochastic...

Mean field interaction in biochemical reaction networks

KAUST Repository

Tembine, Hamidou; Tempone, Raul; Vilanova, Pedro

2011-01-01

In this paper we establish a relationship between chemical dynamics and mean field game dynamics. We show that chemical reaction networks can be studied using noisy mean field limits. We provide deterministic, noisy and switching mean field limits

Retardation and dispersive effects in the nuclear mean field

International Nuclear Information System (INIS)

Mahaux, C.; Davies, K.T.R.; Satchler, G.R.

1993-01-01

We consider several parametrizations of the energy dependence of the imaginary part of the mean field, for nucleons as well as heavy ions. These parametrizations specify the energy dependence of the corresponding real part, because the real and imaginary parts are connected by a dispersion relation. The latter can be viewed as equivalent to the causality property. Since Hilbert transforms appear in the dispersion relation and since Fourier transforms give the correspondence between energy dependence and temporal nonlocality, we derive several properties of these transforms which are of particular interest in the present context. The most useful one is that the Fourier transform of a function F(E) which is analytic in the upper half of the complex E-plane can be expressed in terms of the Fourier transform of the imaginary part of F(E) alone. We investigate several schematic models for the mean field. They fall into two main categories. These correspond to the two main definitions which have been proposed for the mean field, namely the self-energy and Feshbach's potential. Both of these definitions can be used for the nucleon-nucleus system, in which case they correspond to two different ways of handling the combined influence of ground state correlations and antisymmetrization. The resulting two mean fields have different energy dependences and, correspondingly, temporal nonlocalities. Feshbach's approach can also be applied to the nucleus-nucleus system. Our schematic models are semi-realistic, in the sense that they all take account of the 'Fermi surface anomaly' for the nucleon-nucleus system or of the 'threshold anomaly' for the nucleus-nucleus case. The temporal nonlocality is investigated for each model. A physical interpretation of this nonlocality is given in terms delay of the response of the medium, in which an incident wave is partially trapped in nonelastic channels and subsequently reemitted. (orig./HSI)

Sourcing for Quality: Cooperating with a Single Supplier or Developing Two Competing Suppliers?

Directory of Open Access Journals (Sweden)

Jingxian Chen

2016-01-01

Full Text Available Supplier efforts regarding product quality are an important issue in outsourcing and play a critical role in a manufacturer’s choice of sourcing strategy. Consider a manufacturer that wants to outsource the manufacturing of two substitute products to external suppliers. This paper studies the strategic interactions under two sourcing strategies: single and dual sourcing. A four-stage noncooperative game model is established to describe each member’s decisions. We further propose four decision scenarios: single sourcing with and without manufacturer quality investment sharing and dual sourcing when suppliers cooperate or do not cooperate on quality decisions. By the backward induction approach, we obtain analytical equilibrium solutions for each decision scenario. By comparing each pair of equilibrium profiles, we find that an appropriate proportion of quality investment sharing by the manufacturer can enable a cooperating strategy with a single supplier to be the dominant strategy. When the manufacturer does not want to share or does not want to share a relatively large portion of its supplier’s quality investment, it will always prefer to develop two competing suppliers when the cost of dual sourcing is sufficiently low. However, dual sourcing can be extremely risky for the manufacturer because the suppliers could provide a relatively low product quality level by cooperating on the quality decision to extract the manufacturer’s profit.

Dynamical Evolution of Properties for Atom and Field in the Process of Two-Photon Absorption and Emission Between Atomic Levels

Science.gov (United States)

Wang, Jian-ming; Xu, Xue-xiang

2018-04-01

Using dressed state method, we cleverly solve the dynamics of atom-field interaction in the process of two-photon absorption and emission between atomic levels. Here we suppose that the atom is initially in the ground state and the optical field is initially in Fock state, coherent state or thermal state, respectively. The properties of the atom, including the population in excited state and ground state, the atom inversion, and the properties for optical field, including the photon number distribution, the mean photon number, the second-order correlation function and the Wigner function, are discussed in detail. We derive their analytical expressions and then make numerical analysis for them. In contrast with Jaynes-Cummings model, some similar results, such as quantum Rabi oscillation, revival and collapse, are also exhibit in our considered model. Besides, some novel nonclassical states are generated.

Mean Field Games Models-A Brief Survey

KAUST Repository

Gomes, Diogo A.

2013-11-20

The mean-field framework was developed to study systems with an infinite number of rational agents in competition, which arise naturally in many applications. The systematic study of these problems was started, in the mathematical community by Lasry and Lions, and independently around the same time in the engineering community by P. Caines, Minyi Huang, and Roland Malhamé. Since these seminal contributions, the research in mean-field games has grown exponentially, and in this paper we present a brief survey of mean-field models as well as recent results and techniques. In the first part of this paper, we study reduced mean-field games, that is, mean-field games, which are written as a system of a Hamilton-Jacobi equation and a transport or Fokker-Planck equation. We start by the derivation of the models and by describing some of the existence results available in the literature. Then we discuss the uniqueness of a solution and propose a definition of relaxed solution for mean-field games that allows to establish uniqueness under minimal regularity hypothesis. A special class of mean-field games that we discuss in some detail is equivalent to the Euler-Lagrange equation of suitable functionals. We present in detail various additional examples, including extensions to population dynamics models. This section ends with a brief overview of the random variables point of view as well as some applications to extended mean-field games models. These extended models arise in problems where the costs incurred by the agents depend not only on the distribution of the other agents, but also on their actions. The second part of the paper concerns mean-field games in master form. These mean-field games can be modeled as a partial differential equation in an infinite dimensional space. We discuss both deterministic models as well as problems where the agents are correlated. We end the paper with a mean-field model for price impact. © 2013 Springer Science+Business Media New York.

Mean Field Games Models-A Brief Survey

KAUST Repository

Gomes, Diogo A.; Saú de, Joã o

2013-01-01

The mean-field framework was developed to study systems with an infinite number of rational agents in competition, which arise naturally in many applications. The systematic study of these problems was started, in the mathematical community by Lasry and Lions, and independently around the same time in the engineering community by P. Caines, Minyi Huang, and Roland Malhamé. Since these seminal contributions, the research in mean-field games has grown exponentially, and in this paper we present a brief survey of mean-field models as well as recent results and techniques. In the first part of this paper, we study reduced mean-field games, that is, mean-field games, which are written as a system of a Hamilton-Jacobi equation and a transport or Fokker-Planck equation. We start by the derivation of the models and by describing some of the existence results available in the literature. Then we discuss the uniqueness of a solution and propose a definition of relaxed solution for mean-field games that allows to establish uniqueness under minimal regularity hypothesis. A special class of mean-field games that we discuss in some detail is equivalent to the Euler-Lagrange equation of suitable functionals. We present in detail various additional examples, including extensions to population dynamics models. This section ends with a brief overview of the random variables point of view as well as some applications to extended mean-field games models. These extended models arise in problems where the costs incurred by the agents depend not only on the distribution of the other agents, but also on their actions. The second part of the paper concerns mean-field games in master form. These mean-field games can be modeled as a partial differential equation in an infinite dimensional space. We discuss both deterministic models as well as problems where the agents are correlated. We end the paper with a mean-field model for price impact. © 2013 Springer Science+Business Media New York.

An fMRI study of joint action – varying levels of cooperation correlates with activity in sensorimotor control, but not mentalization, networks

Directory of Open Access Journals (Sweden)

Thierry eChaminade

2012-06-01

Full Text Available As social agents, humans continuously interact with with the people around them. Here, motor cooperation was investigated by designing a situation in which pairs of participants, one being scanned with fMRI, controlled jointly a visually presented object with joystick movements. The object oscillated dynamically along two dimensions, shades of pink and width of gratings, corresponding to the two cardinal directions of joystick movements. While the overall control of each participant on the object was kept constant, the amount of cooperation along the two dimensions varied along four levels, from no (each participant controlled exclusively one dimension to full (each participant controlled half of each dimension cooperation. Increasing cooperation correlated with BOLD signal in the left parietal operculum and anterior cingulate cortex, while decreasing cooperation correlated with activity in the right inferior frontal and superior temporal gyri, in the intraparietal sulci and inferior temporal gyrii bilaterally, and in the dorsomedial prefrontal cortex. As joint control improved with the level of cooperation, we assessed the brain responses correlating with joint performance, and found that activity in most of the areas associated with levels of cooperation also correlated with the joint performance. The only brain area found exclusively in the negative correlation with cooperation was within the posterior region of the rostral medial frontal cortex, involved in the monitoring of action outcome. We therefore propose that this region responds to the predictability of visual feedback given the motor commands, which is maximal when participants do not cooperate as they fully control one dimension. Our results therefore indicate that, in the current experimental paradigm, the level of cooperation affects sensorimotor processing, but not mentalizing. Altogether, humans do not need to have access to others’ intentional states to cooperate on a joint

Cooper pair splitter realized in a two-quantum-dot Y-junction.

Science.gov (United States)

Hofstetter, L; Csonka, S; Nygård, J; Schönenberger, C

2009-10-15

Non-locality is a fundamental property of quantum mechanics that manifests itself as correlations between spatially separated parts of a quantum system. A fundamental route for the exploration of such phenomena is the generation of Einstein-Podolsky-Rosen (EPR) pairs of quantum-entangled objects for the test of so-called Bell inequalities. Whereas such experimental tests of non-locality have been successfully conducted with pairwise entangled photons, it has not yet been possible to realize an electronic analogue of it in the solid state, where spin-1/2 mobile electrons are the natural quantum objects. The difficulty stems from the fact that electrons are immersed in a macroscopic ground state-the Fermi sea-which prevents the straightforward generation and splitting of entangled pairs of electrons on demand. A superconductor, however, could act as a source of EPR pairs of electrons, because its ground-state is composed of Cooper pairs in a spin-singlet state. These Cooper pairs can be extracted from a superconductor by tunnelling, but, to obtain an efficient EPR source of entangled electrons, the splitting of the Cooper pairs into separate electrons has to be enforced. This can be achieved by having the electrons 'repel' each other by Coulomb interaction. Controlled Cooper pair splitting can thereby be realized by coupling of the superconductor to two normal metal drain contacts by means of individually tunable quantum dots. Here we demonstrate the first experimental realization of such a tunable Cooper pair splitter, which shows a surprisingly high efficiency. Our findings open a route towards a first test of the EPR paradox and Bell inequalities in the solid state.

Mean-field theory and solitonic matter

International Nuclear Information System (INIS)

Cohen, T.D.

1989-01-01

Finite density solitonic matter is considered in the context of quantum field theory. Mean-field theory, which provides a reasonable description for single-soliton properties gives rise to a crystalline description. A heuristic description of solitonic matter is given which shows that the low-density limit of solitonic matter (the limit which is presumably relevant for nuclear matter) does not commute with the mean-field theory limit and gives rise to a Fermi-gas description of the system. It is shown on the basis of a formal expansion of simple soliton models in terms of the coupling constant why one expects mean-field theory to fail at low densities and why the corrections to mean-field theory are nonperturbative. This heuristic description is tested against an exactly solvable 1+1 dimensional model (the sine-Gordon model) and found to give the correct behavior. The relevance of these results to the program of doing nuclear physics based on soliton models is discussed. (orig.)

The Population Inversion and the Entropy of a Moving Two-Level Atom in Interaction with a Quantized Field

Science.gov (United States)

Abo-Kahla, D. A. M.; Abdel-Aty, M.; Farouk, A.

2018-05-01

An atom with only two energy eigenvalues is described by a two-dimensional state space spanned by the two energy eigenstates is called a two-level atom. We consider the interaction between a two-level atom system with a constant velocity. An analytic solution of the systems which interacts with a quantized field is provided. Furthermore, the significant effect of the temperature on the atomic inversion, the purity and the information entropy are discussed in case of the initial state either an exited state or a maximally mixed state. Additionally, the effect of the half wavelengths number of the field-mode is investigated.

The limits of the mean field

International Nuclear Information System (INIS)

Guerra, E.M. de

2001-01-01

In these talks, we review non relativistic selfconsistent mean field theories, their scope and limitations. We first discuss static and time dependent mean field approaches for particles and quasiparticles, together with applications. We then discuss extensions that go beyond the non-relativistic independent particle limit. On the one hand, we consider extensions concerned with restoration of symmetries and with the treatment of collective modes, particularly by means of quantized ATDHF. On the other hand, we consider extensions concerned with the relativistic dynamics of bound nucleons. We present data on nucleon momentum distributions that show the need for relativistic mean field approach and probe the limits of the mean field concept. Illustrative applications of various methods are presented stressing the role that selfconsistency plays in providing a unifying reliable framework to study all sorts of properties and phenomena. From global properties such as size, mass, lifetime,.., to detailed structure in excitation spectra (high spin, RPA modes,..), as well as charge, magnetization and velocity distributions. (orig.)

Mean field interaction in biochemical reaction networks

KAUST Repository

Tembine, Hamidou

2011-09-01

In this paper we establish a relationship between chemical dynamics and mean field game dynamics. We show that chemical reaction networks can be studied using noisy mean field limits. We provide deterministic, noisy and switching mean field limits and illustrate them with numerical examples. © 2011 IEEE.

Cooperation makes two less-creative individuals turn into a highly-creative pair.

Science.gov (United States)

Xue, Hua; Lu, Kelong; Hao, Ning

2018-05-15

This study aimed to investigate which type of group (e.g., consisting of less-creative or highly-creative individuals) would perform better in solving creativity problems, and explore the underlying inter-brain neural correlates between team members. A preliminary test (an alternative-uses task) was performed to rank individuals' level of creativity, and divide participants into three types of dyads: high-high (two highly-creative individuals), low-low (two less-creative individuals), and high-low (one highly-creative and one less-creative individual). Dyads were then asked to solve a realistic presented problem (RPP; a typical creativity problem) during which a functional near-infrared spectroscopy (fNIRS)-based hyperscanning device was used to record the variation of interpersonal brain synchronization (IBS). Results revealed that less-creative individuals, while working together, would perform as well as highly-creative individuals. The low-low dyads showed higher levels of cooperation behaviour than the other two types of dyads. The fNIRS results revealed increased IBS only for low-low dyads at PFC (prefrontal cortex) and rTPJ (right temporal-parietal junction) brain regions during RPP task performance. In the rDLPFC (right dorsolateral prefrontal cortex), the IBS in the low-low dyads was stronger than that of high-high and high-low dyads. In the rTPJ, the IBS in the low-low dyads was only stronger than that of the high-low dyads. Besides, the IBS at rDLPFC and rTPJ regions in the low-low dyads was positively correlated with their cooperation behaviour and group creative performance. These findings indicated when two less-creative individuals worked on a creativity problem together, they tended to cooperate with each other (indicated by both behaviour index and increased IBS at rDLPFC and rTPJ), which benefited their creative performance. Copyright © 2018 Elsevier Inc. All rights reserved.

A Stochastic Maximum Principle for Risk-Sensitive Mean-Field Type Control

KAUST Repository

Djehiche, Boualem; Tembine, Hamidou; Tempone, Raul

2015-01-01

In this paper we study mean-field type control problems with risk-sensitive performance functionals. We establish a stochastic maximum principle (SMP) for optimal control of stochastic differential equations (SDEs) of mean-field type, in which the drift and the diffusion coefficients as well as the performance functional depend not only on the state and the control but also on the mean of the distribution of the state. Our result extends the risk-sensitive SMP (without mean-field coupling) of Lim and Zhou (2005), derived for feedback (or Markov) type optimal controls, to optimal control problems for non-Markovian dynamics which may be time-inconsistent in the sense that the Bellman optimality principle does not hold. In our approach to the risk-sensitive SMP, the smoothness assumption on the value-function imposed in Lim and Zhou (2005) needs not be satisfied. For a general action space a Peng's type SMP is derived, specifying the necessary conditions for optimality. Two examples are carried out to illustrate the proposed risk-sensitive mean-field type SMP under linear stochastic dynamics with exponential quadratic cost function. Explicit solutions are given for both mean-field free and mean-field models.

A Stochastic Maximum Principle for Risk-Sensitive Mean-Field Type Control

KAUST Repository

Djehiche, Boualem

2015-02-24

In this paper we study mean-field type control problems with risk-sensitive performance functionals. We establish a stochastic maximum principle (SMP) for optimal control of stochastic differential equations (SDEs) of mean-field type, in which the drift and the diffusion coefficients as well as the performance functional depend not only on the state and the control but also on the mean of the distribution of the state. Our result extends the risk-sensitive SMP (without mean-field coupling) of Lim and Zhou (2005), derived for feedback (or Markov) type optimal controls, to optimal control problems for non-Markovian dynamics which may be time-inconsistent in the sense that the Bellman optimality principle does not hold. In our approach to the risk-sensitive SMP, the smoothness assumption on the value-function imposed in Lim and Zhou (2005) needs not be satisfied. For a general action space a Peng\\'s type SMP is derived, specifying the necessary conditions for optimality. Two examples are carried out to illustrate the proposed risk-sensitive mean-field type SMP under linear stochastic dynamics with exponential quadratic cost function. Explicit solutions are given for both mean-field free and mean-field models.

Third-party punishment increases cooperation in children through (misaligned) expectations and conditional cooperation.

Science.gov (United States)

Lergetporer, Philipp; Angerer, Silvia; Glätzle-Rützler, Daniela; Sutter, Matthias

2014-05-13

The human ability to establish cooperation, even in large groups of genetically unrelated strangers, depends upon the enforcement of cooperation norms. Third-party punishment is one important factor to explain high levels of cooperation among humans, although it is still somewhat disputed whether other animal species also use this mechanism for promoting cooperation. We study the effectiveness of third-party punishment to increase children's cooperative behavior in a large-scale cooperation game. Based on an experiment with 1,120 children, aged 7 to 11 y, we find that the threat of third-party punishment more than doubles cooperation rates, despite the fact that children are rarely willing to execute costly punishment. We can show that the higher cooperation levels with third-party punishment are driven by two components. First, cooperation is a rational (expected payoff-maximizing) response to incorrect beliefs about the punishment behavior of third parties. Second, cooperation is a conditionally cooperative reaction to correct beliefs that third party punishment will increase a partner's level of cooperation.

Socio-economic applications of finite state mean field games

KAUST Repository

Gomes, Diogo A.

2014-10-06

In this paper, we present different applications of finite state mean field games to socio-economic sciences. Examples include paradigm shifts in the scientific community or consumer choice behaviour in the free market. The corresponding finite state mean field game models are hyperbolic systems of partial differential equations, for which we present and validate different numerical methods. We illustrate the behaviour of solutions with various numerical experiments,which show interesting phenomena such as shock formation. Hence, we conclude with an investigation of the shock structure in the case of two-state problems.

Effect of a uniform magnetic field on dielectric two-phase bubbly flows using the level set method

International Nuclear Information System (INIS)

Ansari, M.R.; Hadidi, A.; Nimvari, M.E.

2012-01-01

In this study, the behavior of a single bubble in a dielectric viscous fluid under a uniform magnetic field has been simulated numerically using the Level Set method in two-phase bubbly flow. The two-phase bubbly flow was considered to be laminar and homogeneous. Deformation of the bubble was considered to be due to buoyancy and magnetic forces induced from the external applied magnetic field. A computer code was developed to solve the problem using the flow field, the interface of two phases, and the magnetic field. The Finite Volume method was applied using the SIMPLE algorithm to discretize the governing equations. Using this algorithm enables us to calculate the pressure parameter, which has been eliminated by previous researchers because of the complexity of the two-phase flow. The finite difference method was used to solve the magnetic field equation. The results outlined in the present study agree well with the existing experimental data and numerical results. These results show that the magnetic field affects and controls the shape, size, velocity, and location of the bubble. - Highlights: ►A bubble behavior was simulated numerically. ► A single bubble behavior was considered in a dielectric viscous fluid. ► A uniform magnetic field is used to study a bubble behavior. ► Deformation of the bubble was considered using the Level Set method. ► The magnetic field affects the shape, size, velocity, and location of the bubble.

Threshold Games and Cooperation on Multiplayer Graphs.

Directory of Open Access Journals (Sweden)

Kaare B Mikkelsen

Full Text Available The study investigates the effect on cooperation in multiplayer games, when the population from which all individuals are drawn is structured-i.e. when a given individual is only competing with a small subset of the entire population.To optimize the focus on multiplayer effects, a class of games were chosen for which the payoff depends nonlinearly on the number of cooperators-this ensures that the game cannot be represented as a sum of pair-wise interactions, and increases the likelihood of observing behaviour different from that seen in two-player games. The chosen class of games are named "threshold games", and are defined by a threshold, M > 0, which describes the minimal number of cooperators in a given match required for all the participants to receive a benefit. The model was studied primarily through numerical simulations of large populations of individuals, each with interaction neighbourhoods described by various classes of networks.When comparing the level of cooperation in a structured population to the mean-field model, we find that most types of structure lead to a decrease in cooperation. This is both interesting and novel, simply due to the generality and breadth of relevance of the model-it is likely that any model with similar payoff structure exhibits related behaviour. More importantly, we find that the details of the behaviour depends to a large extent on the size of the immediate neighbourhoods of the individuals, as dictated by the network structure. In effect, the players behave as if they are part of a much smaller, fully mixed, population, which we suggest an expression for.

Cellular image segmentation using n-agent cooperative game theory

Science.gov (United States)

Dimock, Ian B.; Wan, Justin W. L.

2016-03-01

Image segmentation is an important problem in computer vision and has significant applications in the segmentation of cellular images. Many different imaging techniques exist and produce a variety of image properties which pose difficulties to image segmentation routines. Bright-field images are particularly challenging because of the non-uniform shape of the cells, the low contrast between cells and background, and imaging artifacts such as halos and broken edges. Classical segmentation techniques often produce poor results on these challenging images. Previous attempts at bright-field imaging are often limited in scope to the images that they segment. In this paper, we introduce a new algorithm for automatically segmenting cellular images. The algorithm incorporates two game theoretic models which allow each pixel to act as an independent agent with the goal of selecting their best labelling strategy. In the non-cooperative model, the pixels choose strategies greedily based only on local information. In the cooperative model, the pixels can form coalitions, which select labelling strategies that benefit the entire group. Combining these two models produces a method which allows the pixels to balance both local and global information when selecting their label. With the addition of k-means and active contour techniques for initialization and post-processing purposes, we achieve a robust segmentation routine. The algorithm is applied to several cell image datasets including bright-field images, fluorescent images and simulated images. Experiments show that the algorithm produces good segmentation results across the variety of datasets which differ in cell density, cell shape, contrast, and noise levels.

Decentralized Cooperation Strategies in Two-Dimensional Traffic of Cellular Automata

International Nuclear Information System (INIS)

Fang Jun; Qin Zheng; Xu Zhaohui; Chen Xiqun; Leng Biao; Jiang Zineng

2012-01-01

We study the two-dimensional traffic of cellular automata using computer simulation. We propose two type of decentralized cooperation strategies, which are called stepping aside (CS-SA) and choosing alternative routes (CS-CAR) respectively. We introduce them into an existing two-dimensional cellular automata (CA) model. CS-SA is designed to prohibit a kind of ping-pong jump when two objects standing together try to move in opposite directions. CS-CAR is designed to change the solution of conflict in parallel update. CS-CAR encourages the objects involved in parallel conflicts choose their alternative routes instead of waiting. We also combine the two cooperation strategies (CS-SA-CAR) to test their combined effects. It is found that the system keeps on a partial jam phase with nonzero velocity and flow until the density reaches one. The ratios of the ping-pong jump and the waiting objects involved in conflict are decreased obviously, especially at the free phase. And the average flow is improved by the three cooperation strategies. Although the average travel time is lengthened a bit by CS-CAR, it is shorten by CS-SA and CS-SA-CAR. In addition, we discuss the advantage and applicability of decentralized cooperation modeling.

Dependence of synchronization transitions on mean field approach in two-way coupled neural system

Science.gov (United States)

Shi, J. C.; Luo, M.; Huang, C. S.

2018-03-01

This work investigates the synchronization transitions in two-way coupled neural system by mean field approach. Results show that, there exists a critical noise intensity for the synchronization transitions, i.e., above (or below) the critical noise intensity, the synchronization transitions are decreased (or hardly change) with increasing the noise intensity. Meanwhile, the heterogeneity effect plays a negative role for the synchronization transitions, and above critical coupling strength, the heterogeneity effect on synchronization transitions can be negligible. Furthermore, when an external signal is introduced into the coupled system, the novel frequency-induced and amplitude-induced synchronization transitions are found, and there exist an optimal frequency and an optimal amplitude of external signal which makes the system to display the best synchronization transitions. In particular, it is observed that the synchronization transitions can not be further affected above critical frequency of external signal.

An Unusual Partnership: Brazilian-Italian Forms of Cooperation in the Nuclear Field (1951-1986)

International Nuclear Information System (INIS)

Patti, Carlo

2017-01-01

This chapter discusses the Brazilian-Italian cooperation in the nuclear field between the early 1950s and 1986. Since the late 1930s, Italian or Italian-Brazilian scientists promoted the development of studies in nuclear physics. Immediately after World War II, the Brazilian-Italian collaboration continued. Between the 1950s and the 1970s, Brazilian nuclear scientists studied in Italian institutions. Relying on primary sources from Brazilian archives and oral history interviews with protagonists of the Brazilian nuclear program, this chapter explore the relations between Italy and Brazil from 1951, the year of the establishment of the Brazilian nuclear program, until the 1980s. This study focuses on the bidirectional transfer of knowledge on sensitive technologies, and on the formal and informal cooperation between the two countries.

Gap junctions mediate large-scale Turing structures in a mean-field cortex driven by subcortical noise

Science.gov (United States)

Steyn-Ross, Moira L.; Steyn-Ross, D. A.; Wilson, M. T.; Sleigh, J. W.

2007-07-01

One of the grand puzzles in neuroscience is establishing the link between cognition and the disparate patterns of spontaneous and task-induced brain activity that can be measured clinically using a wide range of detection modalities such as scalp electrodes and imaging tomography. High-level brain function is not a single-neuron property, yet emerges as a cooperative phenomenon of multiply-interacting populations of neurons. Therefore a fruitful modeling approach is to picture the cerebral cortex as a continuum characterized by parameters that have been averaged over a small volume of cortical tissue. Such mean-field cortical models have been used to investigate gross patterns of brain behavior such as anesthesia, the cycles of natural sleep, memory and erasure in slow-wave sleep, and epilepsy. There is persuasive and accumulating evidence that direct gap-junction connections between inhibitory neurons promote synchronous oscillatory behavior both locally and across distances of some centimeters, but, to date, continuum models have ignored gap-junction connectivity. In this paper we employ simple mean-field arguments to derive an expression for D2 , the diffusive coupling strength arising from gap-junction connections between inhibitory neurons. Using recent neurophysiological measurements reported by Fukuda [J. Neurosci. 26, 3434 (2006)], we estimate an upper limit of D2≈0.6cm2 . We apply a linear stability analysis to a standard mean-field cortical model, augmented with gap-junction diffusion, and find this value for the diffusive coupling strength to be close to the critical value required to destabilize the homogeneous steady state. Computer simulations demonstrate that larger values of D2 cause the noise-driven model cortex to spontaneously crystalize into random mazelike Turing structures: centimeter-scale spatial patterns in which regions of high-firing activity are intermixed with regions of low-firing activity. These structures are consistent with the

Relativistic mean-field mass models

Energy Technology Data Exchange (ETDEWEB)

Pena-Arteaga, D.; Goriely, S.; Chamel, N. [Universite Libre de Bruxelles, Institut d' Astronomie et d' Astrophysique, CP-226, Brussels (Belgium)

2016-10-15

We present a new effort to develop viable mass models within the relativistic mean-field approach with density-dependent meson couplings, separable pairing and microscopic estimations for the translational and rotational correction energies. Two interactions, DD-MEB1 and DD-MEB2, are fitted to essentially all experimental masses, and also to charge radii and infinite nuclear matter properties as determined by microscopic models using realistic interactions. While DD-MEB1 includes the σ, ω and ρ meson fields, DD-MEB2 also considers the δ meson. Both mass models describe the 2353 experimental masses with a root mean square deviation of about 1.1 MeV and the 882 measured charge radii with a root mean square deviation of 0.029 fm. In addition, we show that the Pb isotopic shifts and moments of inertia are rather well reproduced, and the equation of state in pure neutron matter as well as symmetric nuclear matter are in relatively good agreement with existing realistic calculations. Both models predict a maximum neutron-star mass of more than 2.6 solar masses, and thus are able to accommodate the heaviest neutron stars observed so far. However, the new Lagrangians, like all previously determined RMF models, present the drawback of being characterized by a low effective mass, which leads to strong shell effects due to the strong coupling between the spin-orbit splitting and the effective mass. Complete mass tables have been generated and a comparison with other mass models is presented. (orig.)

A mean field approach to the Ising chain in a transverse magnetic field

Science.gov (United States)

Osácar, C.; Pacheco, A. F.

2017-07-01

We evaluate a mean field method to describe the properties of the ground state of the Ising chain in a transverse magnetic field. Specifically, a method of the Bethe-Peierls type is used by solving spin blocks with a self-consistency condition at the borders. The computations include the critical point for the phase transition, exponent of magnetisation and energy density. All results are obtained using basic quantum mechanics at an undergraduate level. The advantages and the limitations of the approach are emphasised.

Four Essays on Corruption and Cooperation

OpenAIRE

Schikora, Jan

2011-01-01

This dissertation contains four separate studies in the fields of corruption and cooperation. The first chapter explicates the mechanism that links the fractionalization of society with its level of corruption within a theoretical model of relational contracting. The other three chapters describe experimental studies. The second and third chapters evaluate two popular anti-corruption policies, the ‘Four-Eyes-Principle’ and ‘Whistle- Blowing’, with respect to their effectiveness in decreasing ...

Mean-field Ohm's law and coaxial helicity injection in force-free plasmas

International Nuclear Information System (INIS)

Weening, R. H.

2011-01-01

A theoretical analysis of steady-state coaxial helicity injection (CHI) in force-free plasmas is presented using a parallel mean-field Ohm's law that includes resistivity η and hyper-resistivity Λ terms. Using Boozer coordinates, a partial differential equation is derived for the time evolution of the mean-field poloidal magnetic flux, or magnetic Hamiltonian function, from the parallel mean-field Ohm's law. A general expression is obtained from the mean-field theory for the efficiency of CHI current drive in force-free plasmas. Inductances of internal energy, magnetic helicity, and poloidal magnetic flux are used to characterize axisymmetric plasma equilibria that have a model current profile. Using the model current profile, a method is suggested to determine the level of magnetohydrodynamic activity at the magnetic axis and the consequent deviation from the completely relaxed Taylor state. The mean-field Ohm's law model suggests that steady-state CHI can be viewed most simply as a boundary layer problem.

Simulations of intermediate-energy heavy-ion collisions within relativistic mean-field two-fluid model

International Nuclear Information System (INIS)

Ivanov, Y.B.; Russkikh, V.N.; Pokrovsky, Y.E. Kurchatov; Ivanov, Y.B.; Russkikh, V.N.; Polrovsky, Y.E.; Henning, P.A.; Henning, P.A.

1995-01-01

A three-dimensional realization of the relativistic mean-field 2-fluid model is described. The first results of analyzing the inclusive data on the yield of nuclear fragments and pions, as well as the Plastic-Ball rapidity distributions of nuclear fragments are presented. For comparison, the calculations within the conventional relativistic hydrodynamical model with the same mean fields are also performed. It is found that all the analysed observables, except the pion spectra, appeared to be fairly insensitive to the nuclear EOS. The sensitivity to the nuclear stopping power is slightly higher. The original sensitivity of the rapidity distributions to the stopping power is smeared out by the Plastic-Ball filter and selection criterion. Nevertheless, one can conclude that the stopping power induced by the Cugnon cross-sections is not quite sufficient for a more adequate reproduction of the experimental data. (authors)

Distinguishing the opponents promotes cooperation in well-mixed populations

Science.gov (United States)

Wardil, Lucas; da Silva, Jafferson K. L.

2010-03-01

Cooperation has been widely studied when an individual strategy is adopted against all coplayers. In this context, some extra mechanisms, such as punishment, reward, memory, and network reciprocity must be introduced in order to keep cooperators alive. Here, we adopt a different point of view. We study the adoption of different strategies against different opponents instead of adoption of the same strategy against all of them. In the context of the prisoner dilemma, we consider an evolutionary process in which strategies that provide more benefits are imitated and the players replace the strategy used in one of the interactions furnishing the worst payoff. Individuals are set in a well-mixed population, so that network reciprocity effect is excluded and both synchronous and asynchronous updates are analyzed. As a consequence of the replacement rule, we show that mutual cooperation is never destroyed and the initial fraction of mutual cooperation is a lower bound for the level of cooperation. We show by simulation and mean-field analysis that (i) cooperation dominates for synchronous update and (ii) only the initial mutual cooperation is maintained for asynchronous update. As a side effect of the replacement rule, an “implicit punishment” mechanism comes up in a way that exploitations are always neutralized providing evolutionary stability for cooperation.

Spectral properties of a V-type three-level atom driven by two bichromatic fields

International Nuclear Information System (INIS)

Li Peng; Nakajima, Takashi; Ning Xijing

2006-01-01

We theoretically investigate the spectral properties of a V-type three-level atom driven by two bichromatic fields with a common frequency difference. By decomposing the master equation using harmonic expansions and invoking quantum regression theorem, fluorescence and probe absorption spectra of the strong atomic transition are numerically calculated under the steady state condition. We find that both fluorescence and absorption spectra exhibit two interesting features, which are equidistant comblike structures and phase-dependent line splittings. In the comblike structures, each fluorescence peak can be made subnatural by manipulating the relative intensities of the coupling fields, while for the absorption lines only the central peak can be narrowed. Line splittings are induced by the relative phase delay between the envelopes of the amplitudes of the two bichromatic fields. Interestingly, we find that the manipulation of the relative phase delay results in the emergence of sharp subnatural dips in the absorption spectra. As a natural consequence of the subnatural absorption dips, absorption spectra in atomic vapors exhibit striking subnatural burning holes for the counterpropagating probe beam geometry

COOPERATIVE LEARNING AS A MEANS OF STIMULATING LIFE SKILLS IN PROFESSIONALLY-BIASED FOREIGN LANGUAGE TEACHING

Directory of Open Access Journals (Sweden)

Alexander Komarov

2016-02-01

Full Text Available The article is devoted to the contribution of foreign language learning to stimulating students’ life skills at non-linguistic higher institutions. In the article, the author considers the possibilities of motivating students to exercise life skills in the process of foreign language instruction. The author analyses the cooperative learning technology as a means that enables students to be involved into interaction with one another as well as it develops their team-building skills to successfully cooperate and communicate with each other. The author describes different forms of cooperative leaning, which give students an opportunity to mutually enrich and complement each other’s skills in foreign language learning. The author argues that cooperative learning technology stimulates the students’ existent life skills and makes them work in the process of professionally-biased instruction of a foreign language.

Nonasymptotic mean-field games

KAUST Repository

Tembine, Hamidou

2014-12-01

Mean-field games have been studied under the assumption of very large number of players. For such large systems, the basic idea consists to approximate large games by a stylized game model with a continuum of players. The approach has been shown to be useful in some applications. However, the stylized game model with continuum of decision-makers is rarely observed in practice and the approximation proposed in the asymptotic regime is meaningless for networked systems with few entities. In this paper we propose a mean-field framework that is suitable not only for large systems but also for a small world with few number of entities. The applicability of the proposed framework is illustrated through a dynamic auction with asymmetric valuation distributions.

Nonasymptotic mean-field games

KAUST Repository

Tembine, Hamidou

2014-12-01

Mean-field games have been studied under the assumption of very large number of players. For such large systems, the basic idea consists of approximating large games by a stylized game model with a continuum of players. The approach has been shown to be useful in some applications. However, the stylized game model with continuum of decision-makers is rarely observed in practice and the approximation proposed in the asymptotic regime is meaningless for networks with few entities. In this paper, we propose a mean-field framework that is suitable not only for large systems but also for a small world with few number of entities. The applicability of the proposed framework is illustrated through various examples including dynamic auction with asymmetric valuation distributions, and spiteful bidders.

Derivation of mean-field dynamics for fermions

International Nuclear Information System (INIS)

Petrat, Soeren

2014-01-01

In this work, we derive the time-dependent Hartree(-Fock) equations as an effective dynamics for fermionic many-particle systems. Our main results are the first for a quantum mechanical mean-field dynamics for fermions; in previous works, the mean-field limit is usually either coupled to a semiclassical limit, or the interaction is scaled down so much, that the system behaves freely for large particle number N. We mainly consider systems with total kinetic energy bounded by const.N and long-range interaction potentials, e.g., Coulomb interaction. Examples for such systems are large molecules or certain solid states. Our analysis also applies to attractive interactions, as, e.g., in fermionic stars. The fermionic Hartree(-Fock) equations are a standard tool to describe, e.g., excited states or chemical reactions of large molecules (like proteins). A deeper understanding of these equations as an approximation to the time evolution of a many body quantum system is thus highly relevant. We consider the fermionic Hartree equations (i.e., the Hartree-Fock equations without exchange term) in this work, since the exchange term is subleading in our setting. The main result is that the fermionic Hartree dynamics approximates the Schroedinger dynamics well for large N. This statement becomes exact in the thermodynamic limit N→∞. We give explicit values for the rates of convergence. We prove two types of results. The first type is very general and concerns arbitrary free Hamiltonians (e.g., relativistic, non-relativistic, with external fields) and arbitrary interactions. The theorems give explicit conditions on the solutions to the fermionic Hartree equations under which a derivation of the mean-field dynamics succeeds. The second type of results scrutinizes situations where the conditions are fulfilled. These results are about non-relativistic free Hamiltonians with external fields, systems with total kinetic energy bounded by const.N and with long-range interactions of

The level of influence of trust, commitment, cooperation, and power in the interorganizational relationships of Brazilian credit cooperatives

Directory of Open Access Journals (Sweden)

Denise Maria Martins

Full Text Available Abstract This article aims to analyze the level of influence of trust, commitment, cooperation, and power in the interrelationships of individual credit cooperatives and their central organization in Brazil. The quantitative and descriptive research was developed in unique credit unions linked to the Central Bank of Brazil and the Organization of Brazilian Cooperatives. The data were analyzed using structural equation modeling, with the estimation through partial least squares. The results obtained for the coefficients of determination (R2 of the endogenous latent variables confirmed the assumptions found in the theoretical models of Morgan and Hunt (1994 and Coote, Forrest, and Tam (2003. Statistical significance was also found in the relationships between power and trust, commitment and cooperation, trust and commitment, trust and cooperation, and power and commitment. However, in this study the relationship between power and commitment characterized the significance and was positive between the individual credit cooperatives and their central organization. This is in line with the understanding that power is the solution to resolving conflicts. The research identifies how the constructs of trust, commitment, cooperation, and power show relevance to the alignment of relations between individual credit cooperatives and their central organization.

Cooperative field test program for wind systems

Energy Technology Data Exchange (ETDEWEB)

Bollmeier, W.S. II; Dodge, D.M.

1992-03-01

The objectives of the Federal Wind Energy Program, managed by the US Department of Energy (DOE), are (1) to assist industry and utilities in achieving a multi-regional US market penetration of wind systems, and (2) to establish the United States as the world leader in the development of advanced wind turbine technology. In 1984, the program conducted a series of planning workshops with representatives from the wind energy industry to obtain input on the Five-Year Research Plan then being prepared by DOE. One specific suggestion that came out of these meetings was that the federal program should conduct cooperative research tests with industry to enhance the technology transfer process. It was also felt that the active involvement of industry in DOE-funded research would improve the state of the art of wind turbine technology. DOE established the Cooperative Field Test Program (CFTP) in response to that suggestion. This program was one of the first in DOE to feature joint industry-government research test teams working toward common objectives.

Self-Regulation, Cooperative Learning, and Academic Self-Efficacy: Interactions to Prevent School Failure.

Science.gov (United States)

Fernandez-Rio, Javier; Cecchini, Jose A; Méndez-Gimenez, Antonio; Mendez-Alonso, David; Prieto, Jose A

2017-01-01

Learning to learn and learning to cooperate are two important goals for individuals. Moreover, self regulation has been identified as fundamental to prevent school failure. The goal of the present study was to assess the interactions between self-regulated learning, cooperative learning and academic self-efficacy in secondary education students experiencing cooperative learning as the main pedagogical approach for at least one school year. 2.513 secondary education students (1.308 males, 1.205 females), 12-17 years old ( M = 13.85, SD = 1.29), enrolled in 17 different schools belonging to the National Network of Schools on Cooperative Learning in Spain agreed to participate. They all had experienced this pedagogical approach a minimum of one school year. Participants were asked to complete the cooperative learning questionnaire, the strategies to control the study questionnaire and the global academic self-efficacy questionnaire. Participants were grouped based on their perceptions on cooperative learning and self-regulated learning in their classes. A combination of hierarchical and κ -means cluster analyses was used. Results revealed a four-cluster solution: cluster one included students with low levels of cooperative learning, self-regulated learning and academic self-efficacy, cluster two included students with high levels of cooperative learning, self-regulated learning and academic self-efficacy, cluster three included students with high levels of cooperative learning, low levels of self-regulated learning and intermediate-low levels of academic self-efficacy, and, finally, cluster four included students with high levels of self-regulated learning, low levels of cooperative learning, and intermediate-high levels of academic self-efficacy. Self-regulated learning was found more influential than cooperative learning on students' academic self-efficacy. In cooperative learning contexts students interact through different types of regulations: self, co, and

Self-Regulation, Cooperative Learning, and Academic Self-Efficacy: Interactions to Prevent School Failure

Science.gov (United States)

Fernandez-Rio, Javier; Cecchini, Jose A.; Méndez-Gimenez, Antonio; Mendez-Alonso, David; Prieto, Jose A.

2017-01-01

Learning to learn and learning to cooperate are two important goals for individuals. Moreover, self regulation has been identified as fundamental to prevent school failure. The goal of the present study was to assess the interactions between self-regulated learning, cooperative learning and academic self-efficacy in secondary education students experiencing cooperative learning as the main pedagogical approach for at least one school year. 2.513 secondary education students (1.308 males, 1.205 females), 12–17 years old (M = 13.85, SD = 1.29), enrolled in 17 different schools belonging to the National Network of Schools on Cooperative Learning in Spain agreed to participate. They all had experienced this pedagogical approach a minimum of one school year. Participants were asked to complete the cooperative learning questionnaire, the strategies to control the study questionnaire and the global academic self-efficacy questionnaire. Participants were grouped based on their perceptions on cooperative learning and self-regulated learning in their classes. A combination of hierarchical and κ-means cluster analyses was used. Results revealed a four-cluster solution: cluster one included students with low levels of cooperative learning, self-regulated learning and academic self-efficacy, cluster two included students with high levels of cooperative learning, self-regulated learning and academic self-efficacy, cluster three included students with high levels of cooperative learning, low levels of self-regulated learning and intermediate-low levels of academic self-efficacy, and, finally, cluster four included students with high levels of self-regulated learning, low levels of cooperative learning, and intermediate-high levels of academic self-efficacy. Self-regulated learning was found more influential than cooperative learning on students’ academic self-efficacy. In cooperative learning contexts students interact through different types of regulations: self, co, and

Cooper pair splitters beyond the Coulomb blockade regime

Energy Technology Data Exchange (ETDEWEB)

Amitai, Ehud; Tiwari, Rakesh P.; Nigg, Simon E. [Department of Physics, University of Basel, Klingelbergstrasse 82, 4056 Basel (Switzerland); Walter, Stefan [Institute for Theoretical Physics, University Erlangen Nuernberg, Staudtstrasse 7, 91058 Erlangen (Germany); Schmidt, Thomas L. [Physics and Materials Science Research Unit, University of Luxembourg, L-1511 Luxembourg (Luxembourg)

2016-07-01

We consider the setup of a conventional s-wave Cooper pair splitter. However, we consider the charging energies in the quantum dots to be finite and smaller than the superconducting gap. We find analytically that at low energies the superconductor mediates an inter-dot tunneling term, the spin symmetry of which is influenced by a finite Zeeman field. This effect, together with an electrical tuning scheme of the quantum dot levels, can be used to engineer a non local triplet state on the two quantum dots, thereby extending the non-local state engineering capabilities of the Cooper pair splitter system.

Cooperative Fuzzy Games Approach to Setting Target Levels of ECs in Quality Function Deployment

Directory of Open Access Journals (Sweden)

Zhihui Yang

2014-01-01

Full Text Available Quality function deployment (QFD can provide a means of translating customer requirements (CRs into engineering characteristics (ECs for each stage of product development and production. The main objective of QFD-based product planning is to determine the target levels of ECs for a new product or service. QFD is a breakthrough tool which can effectively reduce the gap between CRs and a new product/service. Even though there are conflicts among some ECs, the objective of developing new product is to maximize the overall customer satisfaction. Therefore, there may be room for cooperation among ECs. A cooperative game framework combined with fuzzy set theory is developed to determine the target levels of the ECs in QFD. The key to develop the model is the formulation of the bargaining function. In the proposed methodology, the players are viewed as the membership functions of ECs to formulate the bargaining function. The solution for the proposed model is Pareto-optimal. An illustrated example is cited to demonstrate the application and performance of the proposed approach.

Cooperative fuzzy games approach to setting target levels of ECs in quality function deployment.

Science.gov (United States)

Yang, Zhihui; Chen, Yizeng; Yin, Yunqiang

2014-01-01

Quality function deployment (QFD) can provide a means of translating customer requirements (CRs) into engineering characteristics (ECs) for each stage of product development and production. The main objective of QFD-based product planning is to determine the target levels of ECs for a new product or service. QFD is a breakthrough tool which can effectively reduce the gap between CRs and a new product/service. Even though there are conflicts among some ECs, the objective of developing new product is to maximize the overall customer satisfaction. Therefore, there may be room for cooperation among ECs. A cooperative game framework combined with fuzzy set theory is developed to determine the target levels of the ECs in QFD. The key to develop the model is the formulation of the bargaining function. In the proposed methodology, the players are viewed as the membership functions of ECs to formulate the bargaining function. The solution for the proposed model is Pareto-optimal. An illustrated example is cited to demonstrate the application and performance of the proposed approach.

Discourse Analysis in Schizophrenic Patients on the Basis of Grice\\'s Cooperative Principles

Directory of Open Access Journals (Sweden)

Ma'soumeh Salmani

2008-07-01

Full Text Available Objective: The ultimate goal of this study is one of the discourse fields analysis, i.e. Grice's cooperative principles. Materials & Methods: In this comparative and case - control study, two groups of normal individuals and schizophrenic patients were selected by simple method from sample of convenience and interviewed based on the spontaneous part of Persian Aphasia Test. All the answers were analyzed with respect to the percent rate of errors in the 4 "cooperative maxims", and the errors were collected. Data were analyzed by Independent T Test, ANOVA, Kruskal Wallis and Mann Whitney. Results: There were significant differences between two groups in respect to all the Grice’s cooperative principles (P<0.001, maxim of quantity (P<0.001, maxim of relevance (P<0.001 and maxim of manner (P=0.02, but in maxim of quality there was no significant differeance (P=0.07. The mean percent of errors in the course of illness, education and age varieties were not significant. Conclusion: Schizophrenic patients have incoherence speech and this problem exists in the discourse field and social interactions, thus the patients frequently fail in observing the Gricean cooperative principles.

Regional co-operation in the nuclear field: The Nordic experience

International Nuclear Information System (INIS)

Marcus, F.R.

1983-01-01

Experience from 25 years of co-operation in the nuclear field between the Nordic countries is described. A pragmatic approach with a minimum of formalism is used. The co-operation takes place mainly through ''horizontal'' channels between corresponding bodies in the different countries - safety authorities, research institutions, electricity producers, etc. In addition, a ''vertical'' co-ordination between these different circles is accomplished through a Nordic Liaison Committee. The experience shows that valuable results can be obtained, mainly through rationalization and improved use of resources. Difficulties, which are inherent in international co-operation, can be reduced, provided that there is a strong political will, an efficient system to promote contacts, and a flexible financing scheme. Apart from the benefits obtained in each of the countries - whether or not it has its own nuclear power - particular advantages accrue when a ''Nordic group'' can present co-ordinated viewpoints on the international scene. (author)

The Two-Level Theory of Verb Meaning: An Approach to Integrating the Semantics of Action with the Mirror Neuron System

Science.gov (United States)

Kemmerer, David; Gonzalez-Castillo, Javier

2010-01-01

Verbs have two separate levels of meaning. One level reflects the uniqueness of every verb and is called the "root". The other level consists of a more austere representation that is shared by all the verbs in a given class and is called the "event structure template". We explore the following hypotheses about how, with specific reference to the…

Pedestrian Flow in the Mean Field Limit

KAUST Repository

Haji Ali, Abdul Lateef

2012-11-01

We study the mean-field limit of a particle-based system modeling the behavior of many indistinguishable pedestrians as their number increases. The base model is a modified version of Helbing\\'s social force model. In the mean-field limit, the time-dependent density of two-dimensional pedestrians satisfies a four-dimensional integro-differential Fokker-Planck equation. To approximate the solution of the Fokker-Planck equation we use a time-splitting approach and solve the diffusion part using a Crank-Nicholson method. The advection part is solved using a Lax-Wendroff-Leveque method or an upwind Backward Euler method depending on the advection speed. Moreover, we use multilevel Monte Carlo to estimate observables from the particle-based system. We discuss these numerical methods, and present numerical results showing the convergence of observables that were calculated using the particle-based model as the number of pedestrians increases to those calculated using the probability density function satisfying the Fokker-Planck equation.

Comparison of two numerical modelling codes for hydraulic and transport calculations in the near-field

International Nuclear Information System (INIS)

Kalin, J.; Petkovsek, B.; Montarnal, Ph.; Genty, A.; Deville, E.; Krivic, J.; Ratej, J.

2011-01-01

In the past years the Slovenian Performance Analysis/Safety Assessment team has performed many generic studies for the future Slovenian low and intermediate level waste repository, most recently a Special Safety Analysis for the Krsko site. The modelling approach was to split the problem into three parts: near-field (detailed model of the repository), far-field (i.e., geosphere) and biosphere. In the Special Safety Analysis the code used to perform the near-field calculations was Hydrus2D. Recently the team has begun a cooperation with the French Commisariat al'Energie Atomique/Saclay (CEA/Saclay) and, as a part of this cooperation, began investigations into using the Alliances numerical platform for near-field calculations in order to compare the overall approach and calculated results. The article presents the comparison between these two codes for a silo-type repository that was considered in the Special Safety Analysis. The physical layout and characteristics of the repository are presented and a hydraulic and transport model of the repository is developed and implemented in Alliances. Some analysis of sensitivity to mesh fineness and to simulation timestep has been preformed and is also presented. The compared quantity is the output flux of radionuclides on the boundary of the model. Finally the results from Hydrus2D and Alliances are compared and the differences and similarities are commented.

Comparison of two numerical modelling codes for hydraulic and transport calculations in the near-field

Energy Technology Data Exchange (ETDEWEB)

Kalin, J., E-mail: jan.kalin@zag.s [Slovenian National Building and Civil Engineering Institute, Dimiceva 12, SI-1000 Ljubljana (Slovenia); Petkovsek, B., E-mail: borut.petkovsek@zag.s [Slovenian National Building and Civil Engineering Institute, Dimiceva 12, SI-1000 Ljubljana (Slovenia); Montarnal, Ph., E-mail: philippe.montarnal@cea.f [CEA/Saclay, DM2S/SFME/LSET, Gif-sur-Yvette, 91191 cedex (France); Genty, A., E-mail: alain.genty@cea.f [CEA/Saclay, DM2S/SFME/LSET, Gif-sur-Yvette, 91191 cedex (France); Deville, E., E-mail: estelle.deville@cea.f [CEA/Saclay, DM2S/SFME/LSET, Gif-sur-Yvette, 91191 cedex (France); Krivic, J., E-mail: jure.krivic@geo-zs.s [Geological Survey of Slovenia, Dimiceva 14, SI-1000 Ljubljana (Slovenia); Ratej, J., E-mail: joze.ratej@geo-zs.s [Geological Survey of Slovenia, Dimiceva 14, SI-1000 Ljubljana (Slovenia)

2011-04-15

In the past years the Slovenian Performance Analysis/Safety Assessment team has performed many generic studies for the future Slovenian low and intermediate level waste repository, most recently a Special Safety Analysis for the Krsko site. The modelling approach was to split the problem into three parts: near-field (detailed model of the repository), far-field (i.e., geosphere) and biosphere. In the Special Safety Analysis the code used to perform the near-field calculations was Hydrus2D. Recently the team has begun a cooperation with the French Commisariat al'Energie Atomique/Saclay (CEA/Saclay) and, as a part of this cooperation, began investigations into using the Alliances numerical platform for near-field calculations in order to compare the overall approach and calculated results. The article presents the comparison between these two codes for a silo-type repository that was considered in the Special Safety Analysis. The physical layout and characteristics of the repository are presented and a hydraulic and transport model of the repository is developed and implemented in Alliances. Some analysis of sensitivity to mesh fineness and to simulation timestep has been preformed and is also presented. The compared quantity is the output flux of radionuclides on the boundary of the model. Finally the results from Hydrus2D and Alliances are compared and the differences and similarities are commented.

Socio-economic applications of finite state mean field games.

Science.gov (United States)

Gomes, Diogo; Velho, Roberto M; Wolfram, Marie-Therese

2014-11-13

In this paper, we present different applications of finite state mean field games to socio-economic sciences. Examples include paradigm shifts in the scientific community or consumer choice behaviour in the free market. The corresponding finite state mean field game models are hyperbolic systems of partial differential equations, for which we present and validate different numerical methods. We illustrate the behaviour of solutions with various numerical experiments, which show interesting phenomena such as shock formation. Hence, we conclude with an investigation of the shock structure in the case of two-state problems. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

Self-consistent mean field forces in turbulent plasmas: Current and momentum relaxation

International Nuclear Information System (INIS)

Hegna, C.C.

1997-08-01

The properties of turbulent plasmas are described using the two-fluid equations. Under some modest assumptions, global constraints for the turbulent mean field forces that act on the ion and electron fluids are derived. These constraints imply a functional form for the parallel mean field forces in the Ohm's law and the momentum balance equation. These forms suggest that the fluctuations attempt to relax the plasma to a state where both the current and the bulk plasma momentum are aligned along the mean magnetic field with proportionality constants that are global constants. Observations of flow profile evolution during discrete dynamo activity in reversed field pinch experiments are interpreted

Five Rules for the Evolution of Cooperation

Science.gov (United States)

Nowak, Martin A.

2006-12-01

Cooperation is needed for evolution to construct new levels of organization. Genomes, cells, multicellular organisms, social insects, and human society are all based on cooperation. Cooperation means that selfish replicators forgo some of their reproductive potential to help one another. But natural selection implies competition and therefore opposes cooperation unless a specific mechanism is at work. Here I discuss five mechanisms for the evolution of cooperation: kin selection, direct reciprocity, indirect reciprocity, network reciprocity, and group selection. For each mechanism, a simple rule is derived that specifies whether natural selection can lead to cooperation.

Regional cooperation based on multilateral international agreements in nuclear field

International Nuclear Information System (INIS)

Valcic, I.

1996-01-01

Multilateral international agreements have defined the framework of behavior and cooperation in various fields and aspects of peaceful use of nuclear energy. Thus, obligations have been defined in the following areas: nonproliferation of nuclear weapons, physical protection of nuclear material, liability for nuclear damage, nuclear safety, early notification about a nuclear accident and assistance in case of nuclear accident. Obligations regarding radioactive waste management should be defined soon. This paper gives a review of obligations from particular agreements with a special emphasis on those which are being realized through mutual cooperation of concerned countries and are important for safe use of nuclear energy. (author)

Nonasymptotic mean-field games

KAUST Repository

Tembine, Hamidou

2014-01-01

a mean-field framework that is suitable not only for large systems but also for a small world with few number of entities. The applicability of the proposed framework is illustrated through various examples including dynamic auction with asymmetric

Selfishness and Cooperation: Challenge for Social Life

Directory of Open Access Journals (Sweden)

Szocik Konrad

2017-07-01

Full Text Available Cooperation is a great challenge for natural selection. Some scholars assume that cooperation could not evolve within the framework of natural selection. It is undeniable that natural selection, at least at the individual level, favors selfishness and defectors. Nonetheless, this selfish tendency does not necessarily imply that cooperation could not evolve by means of natural selection. In this paper, we specifically acknowledge certain basic challenges for the evolution of the human ability to cooperate at the level of large groups. In this paper, we discuss topics like the human ability for “supercooperation,” the importance of repetition and reputation, and Multilevel Selection Theory as the basic mechanisms of evolution of cooperation.

Quantum mean-field approximations for nuclear bound states and tunneling

International Nuclear Information System (INIS)

Negele, J.W.; Levit, S.; Paltiel, Z.; Massachusetts Inst. of Tech., Cambridge

1979-01-01

A conceptual framework has been presented in which observables are approximated in terms of a self-consistent quantum mean-field theory. Since the SPA (Stationary Phase Approximation) determines the optimal mean field to approximate a given observable, it is natural that when one changes the observable, the best mean field to describe it changes as well. Although the theory superficially appears applicable to any observable expressible in terms of an evolution operator, for example an S-matrix element, one would have to go far beyond the SPA to adequately approximate the overlap of two many-body wave functions. The most salient open problems thus concern quantitative assessment of the accuracy of the SPA, reformulation of the theory to accomodate hard cores, and selection of sensible expectation values of few-body operators to address in scattering problems

Mean-field theory of nuclear structure and dynamics

International Nuclear Information System (INIS)

Negele, J.W.

1982-01-01

The physical and theoretical foundations are presented for the mean-field theory of nuclear structure and dynamics. Salient features of the many-body theory of stationary states are reviewed to motivate the time-dependent mean-field approximation. The time-dependent Hartree-Fock approximation and its limitations are discussed and general theoretical formulations are presented which yield time-dependent mean-field equations in lowest approximation and provide suitable frameworks for overcoming various conceptual and practical limitations of the mean-field theory. Particular emphasis is placed on recent developments utilizing functional integral techniques to obtain a quantum mean-field theory applicable to quantized eigenstates, spontaneous fission, the nuclear partition function, and scattering problems. Applications to a number of simple, idealized systems are presented to verify the approximations for solvable problems and to elucidate the essential features of mean-field dynamics. Finally, calculations utilizing moderately realistic geometries and interactions are reviewed which address heavy-ion collisions, fusion, strongly damped collisions, and fission

Nonasymptotic mean-field games

KAUST Repository

Tembine, Hamidou

2014-01-01

propose a mean-field framework that is suitable not only for large systems but also for a small world with few number of entities. The applicability of the proposed framework is illustrated through a dynamic auction with asymmetric valuation distributions.

New Cooperative Mechanisms of Low Energy Nuclear Reactions Using Superlow Energy External Fields

OpenAIRE

Gareev, F. A.; Zhidkova, I. E.

2005-01-01

We proposed a new mechanism of LENR: cooperative processes in whole system - nuclei+atoms+condensed matter can occur at smaller threshold then corresponding ones on free constituents. The cooperative processes can be induced and enhanced by low energy external fields. The excess heat is the emission of internal energy and transmutations at LENR are the result of redistribution inner energy of whole system.

International co-operation in the field of operational safety

International Nuclear Information System (INIS)

Dupuis, M.C.

1988-10-01

Operational safety in nuclear power plants is without doubt a field where international co-operation is in constant progress. Accounting for over 80 per cent of the 400 reactors in service throughout the world, the menber countries of the OECD Nuclear Energy Agency (NEA) are constantly striving to improve the exchange and use of the wealth of information to be gained not just from power plant accidents and incidents but from the routine operation of these facilities. The Committee on the Safety of Nuclear Installations (CSNI) helps the Steering Committee for Nuclear Energy to meet the NEA's objectives in the safety field, namely: - to promote co-operation between the safety bodies of member countries - to contribute to the safety and regulation of nuclear activities. The CSNI relies on the technical back-up of several different working groups made up of experts appointed by the member countries. For the past three years I have had the honour of chairing Principal Working Group 1 (PWG 1), which deals with operating experience and human factor. It is in this capacity that I will attempt to outline the group's various activities and its findings illustrated by a few examples

Mean-field approximation minimizes relative entropy

International Nuclear Information System (INIS)

Bilbro, G.L.; Snyder, W.E.; Mann, R.C.

1991-01-01

The authors derive the mean-field approximation from the information-theoretic principle of minimum relative entropy instead of by minimizing Peierls's inequality for the Weiss free energy of statistical physics theory. They show that information theory leads to the statistical mechanics procedure. As an example, they consider a problem in binary image restoration. They find that mean-field annealing compares favorably with the stochastic approach

Effects of an applied low frequency field on the dynamics of a two-level atom interacting with a single-mode field

International Nuclear Information System (INIS)

Xun-Wei, Xu; Nian-Hua, Liu

2010-01-01

The effects of an applied low frequency field on the dynamics of a two-level atom interacting with a single-mode field are investigated. It is shown that the time evolution of the atomic population is mainly controlled by the coupling constants and the frequency of the low frequency field, which leads to a low frequency modulation function for the time evolution of the upper state population. The amplitude of the modulation function becomes larger as the coupling constants increase. The frequency of the modulation function is proportional to the frequency of the low frequency field, and decreases with increasing coupling constant. (classical areas of phenomenology)

Linear Quadratic Mean Field Type Control and Mean Field Games with Common Noise, with Application to Production of an Exhaustible Resource

Energy Technology Data Exchange (ETDEWEB)

Graber, P. Jameson, E-mail: jameson-graber@baylor.edu [Baylor University, Department of Mathematics (United States)

2016-12-15

We study a general linear quadratic mean field type control problem and connect it to mean field games of a similar type. The solution is given both in terms of a forward/backward system of stochastic differential equations and by a pair of Riccati equations. In certain cases, the solution to the mean field type control is also the equilibrium strategy for a class of mean field games. We use this fact to study an economic model of production of exhaustible resources.

Mean fields and self consistent normal ordering of lattice spin and gauge field theories

International Nuclear Information System (INIS)

Ruehl, W.

1986-01-01

Classical Heisenberg spin models on lattices possess mean field theories that are well defined real field theories on finite lattices. These mean field theories can be self consistently normal ordered. This leads to a considerable improvement over standard mean field theory. This concept is carried over to lattice gauge theories. We construct first an appropriate real mean field theory. The equations determining the Gaussian kernel necessary for self-consistent normal ordering of this mean field theory are derived. (orig.)

Impact of self interaction on the evolution of cooperation in social spatial dilemmas

International Nuclear Information System (INIS)

Ding, Chenxi; Wang, Juan; Zhang, Ying

2016-01-01

Highlights: • A self interaction mechanism is integrated into two classical game models (PDG and SDG). • An additional payoff will be awarded into the cooperative agents for the payoff calculation. • Beyond the fixed interaction strength, distributed interaction strength is considered. • The collective cooperation can be drastically elevated into a higher level. - Abstract: In this paper, a new self interaction mechanism is integrated into two typical pairwise models including the prisoner’s dilemma and snowdrift games, where an additional payoff will be awarded into the cooperative agents. In the prisoner’s dilemma game, we take three types of additional payoffs into account, to be a fixed constant, a random value situated within the positive unilateral interval and a random one uniformly distributed within a bilateral interval. Large quantities of numerical simulations indicate the promotion of cooperation can be very noticeable whether in the case of von Neumann neighborhood or Moore neighborhood. In the meantime, the self interaction will also be extended into the snowdrift game in which two equilibria exist, and the outcomes clearly show that the collective cooperation is still drastically elevated into a higher level. Current results demonstrate that the self interaction might become a potential and effective means to enhance the behavior of cooperation, and be helpful for us to deeply understand the widespread persistence and emergence of cooperation within many animal and human being societies.

European Administrative Cooperation in the Field of Taxation

OpenAIRE

Florin TUDOR

2012-01-01

The operation of different taxation systems in EU member states appears to promote more increasingly the appearance of double taxation entailing fraud and tax evasion. The phenomenon is amplified by the remaining control competences at the national level, and the lack of administrative cooperation in tax matters at EU level is being a decisive factor in delaying the causes with the consequence of prescription of the facts which brings serious damage enhanced EU budget. This study aims to exam...

Cooperative Bacterial Foraging Optimization

Directory of Open Access Journals (Sweden)

Hanning Chen

2009-01-01

Full Text Available Bacterial Foraging Optimization (BFO is a novel optimization algorithm based on the social foraging behavior of E. coli bacteria. This paper presents a variation on the original BFO algorithm, namely, the Cooperative Bacterial Foraging Optimization (CBFO, which significantly improve the original BFO in solving complex optimization problems. This significant improvement is achieved by applying two cooperative approaches to the original BFO, namely, the serial heterogeneous cooperation on the implicit space decomposition level and the serial heterogeneous cooperation on the hybrid space decomposition level. The experiments compare the performance of two CBFO variants with the original BFO, the standard PSO and a real-coded GA on four widely used benchmark functions. The new method shows a marked improvement in performance over the original BFO and appears to be comparable with the PSO and GA.

Obstacle mean-field game problem

KAUST Repository

Gomes, Diogo A.; Patrizi, Stefania

2015-01-01

In this paper, we introduce and study a first-order mean-field game obstacle problem. We examine the case of local dependence on the measure under assumptions that include both the logarithmic case and power-like nonlinearities. Since the obstacle operator is not differentiable, the equations for first-order mean field game problems have to be discussed carefully. Hence, we begin by considering a penalized problem. We prove this problem admits a unique solution satisfying uniform bounds. These bounds serve to pass to the limit in the penalized problem and to characterize the limiting equations. Finally, we prove uniqueness of solutions. © European Mathematical Society 2015.

Nonequilibrium dynamical mean-field theory

Energy Technology Data Exchange (ETDEWEB)

Eckstein, Martin

2009-12-21

The aim of this thesis is the investigation of strongly interacting quantum many-particle systems in nonequilibrium by means of the dynamical mean-field theory (DMFT). An efficient numerical implementation of the nonequilibrium DMFT equations within the Keldysh formalism is provided, as well a discussion of several approaches to solve effective single-site problem to which lattice models such as the Hubbard-model are mapped within DMFT. DMFT is then used to study the relaxation of the thermodynamic state after a sudden increase of the interaction parameter in two different models: the Hubbard model and the Falicov-Kimball model. In the latter case an exact solution can be given, which shows that the state does not even thermalize after infinite waiting times. For a slow change of the interaction, a transition to adiabatic behavior is found. The Hubbard model, on the other hand, shows a very sensitive dependence of the relaxation on the interaction, which may be called a dynamical phase transition. Rapid thermalization only occurs at the interaction parameter which corresponds to this transition. (orig.)

Nonequilibrium dynamical mean-field theory

International Nuclear Information System (INIS)

Eckstein, Martin

2009-01-01

The aim of this thesis is the investigation of strongly interacting quantum many-particle systems in nonequilibrium by means of the dynamical mean-field theory (DMFT). An efficient numerical implementation of the nonequilibrium DMFT equations within the Keldysh formalism is provided, as well a discussion of several approaches to solve effective single-site problem to which lattice models such as the Hubbard-model are mapped within DMFT. DMFT is then used to study the relaxation of the thermodynamic state after a sudden increase of the interaction parameter in two different models: the Hubbard model and the Falicov-Kimball model. In the latter case an exact solution can be given, which shows that the state does not even thermalize after infinite waiting times. For a slow change of the interaction, a transition to adiabatic behavior is found. The Hubbard model, on the other hand, shows a very sensitive dependence of the relaxation on the interaction, which may be called a dynamical phase transition. Rapid thermalization only occurs at the interaction parameter which corresponds to this transition. (orig.)

Cooperative Enhancement Mechanisms of Low Energy Nuclear Reactions Using Superlow Energy External Fields

OpenAIRE

Gareev, F. A.; Zhidkova, I. E.

2006-01-01

We proposed a new mechanism of LENR: cooperative processes in whole system - nuclei+atoms+condensed matter can occur at smaller threshold energies then corresponding ones on free constituents. The cooperative processes can be induced and enhanced by low energy external fields. The excess heat is the emission of internal energy and transmutations at LENR are the result of redistribution inner energy of whole system.

Investigating the Effects of Group Investigation (GI and Cooperative Integrated Reading and Comprehension (CIRC as the Cooperative Learning Techniques on Learner's Reading Comprehension

Directory of Open Access Journals (Sweden)

Mohammad Amin Karafkan

2015-11-01

Full Text Available Cooperative learning consists of some techniques for helping students work together more effectively. This study investigated the effects of Group Investigation (GI and Cooperative Integrated Reading and Composition (CIRC as cooperative learning techniques on Iranian EFL learners’ reading comprehension at an intermediate level. The participants of the study were 207 male students who studied at an intermediate level at ILI. The participants were randomly assigned into three equal groups: one control group and two experimental groups. The control group was instructed via conventional technique following an individualistic instructional approach. One experimental group received GI technique. The other experimental group received CIRC technique. The findings showed that there was a meaningful difference between the mean of the reading comprehension score of GI experimental group and CRIC experimental group. CRIC technique is more effective than GI technique in enhancing the reading comprehension test scores of students.

Effect of migration based on strategy and cost on the evolution of cooperation

International Nuclear Information System (INIS)

Li, Yan; Ye, Hang

2015-01-01

Highlights: •Propose a migration based on strategy and cost in the Prisoner’s Dilemma Game. •The level of cooperation without mutation is higher than that with mutation. •Increased costs have no effect on the level of cooperation without mutation. •The level of cooperation decreases with the increase in cost with mutation. •An optimal density value ρ resulting in the maximum level of cooperation exists. -- Abstract: Humans consider not only their own ability but also the environment around them during the process of migration. Based on this fact, we introduce migration based on strategy and cost into the Spatial Prisoner’s Dilemma Game on a two-dimensional grid. The migration means that agents cannot move when all of the neighbors are cooperators; otherwise, agents move with a probability related to payoff and cost. The result obtained by the computer simulation shows that the moving mechanism based on strategy and cost improves the level of cooperation in a wide parameter space. This occurs because movement based on strategy effectively keeps the cooperative clusters and because movement based on cost effectively regulates the rate of movement. Both types of movement provide a favorable guarantee for the evolution of stable cooperation under the mutation rate q = 0.0. In addition, we discuss the effectiveness of the migration mechanism in the evolution of cooperation under the mutation rate q = 0.001. The result indicates that a higher level of cooperation is obtained at a lower migration cost, whereas cooperation is suppressed at a higher migration cost. Our work may provide an effective method for understanding the emergence of cooperation in our society

Twelve years of cooperation in the field of radiation protection

Energy Technology Data Exchange (ETDEWEB)

Grapengiesser, Sten; Bennerstedt, Torkel

2005-06-01

SSI has pursued an international cooperation program since 1992 within the field of radiation protection and emergency preparedness for radiation accidents with the three Baltic countries as main beneficiaries. As the Baltic countries are members of the EU since May 2004, this bilateral support will now be phased out and replaced with other forms of cooperation. During the years passed, a large number of activities have been launched with a total budget of some 14 million ECU. The Baltic radiation protection authorities have played a big role in the cooperation and Baltic ministries, universities, nuclear technology installations and other industries using radiation have also been engaged in the projects. SKI, SKB, Studsvik and the Swedish nuclear power plants should be mentioned as major cooperation partners on the Swedish side. During autumn 2004 when such a large coordinated work program was coming to an end, SSI decided to hold a seminar with the purpose to follow up experiences from the work and discuss coming forms of cooperation. The seminar took place on the 18 of November 2004 and gathered some 80 participants, 29 of which from the Baltic countries. It was opened by Lars-Erik Holm, the SSI Director General, and the three Baltic countries then presented their views and impressions from the passed years of cooperation. The seminar was concluded with a panel discussion on 'How to proceed from today's situation'. The result was that SSI invited to a new coordination meeting during autumn 2005 to follow up and discuss coordination of radiation protection around the Baltic Sea together with the other Nordic radiation protection authorities.

Twelve years of cooperation in the field of radiation protection

International Nuclear Information System (INIS)

Grapengiesser, Sten; Bennerstedt, Torkel

2005-06-01

SSI has pursued an international cooperation program since 1992 within the field of radiation protection and emergency preparedness for radiation accidents with the three Baltic countries as main beneficiaries. As the Baltic countries are members of the EU since May 2004, this bilateral support will now be phased out and replaced with other forms of cooperation. During the years passed, a large number of activities have been launched with a total budget of some 14 million ECU. The Baltic radiation protection authorities have played a big role in the cooperation and Baltic ministries, universities, nuclear technology installations and other industries using radiation have also been engaged in the projects. SKI, SKB, Studsvik and the Swedish nuclear power plants should be mentioned as major cooperation partners on the Swedish side. During autumn 2004 when such a large coordinated work program was coming to an end, SSI decided to hold a seminar with the purpose to follow up experiences from the work and discuss coming forms of cooperation. The seminar took place on the 18 of November 2004 and gathered some 80 participants, 29 of which from the Baltic countries. It was opened by Lars-Erik Holm, the SSI Director General, and the three Baltic countries then presented their views and impressions from the passed years of cooperation. The seminar was concluded with a panel discussion on 'How to proceed from today's situation'. The result was that SSI invited to a new coordination meeting during autumn 2005 to follow up and discuss coordination of radiation protection around the Baltic Sea together with the other Nordic radiation protection authorities

Twelve years of cooperation in the field of radiation protection

Energy Technology Data Exchange (ETDEWEB)

Grapengiesser, Sten; Bennerstedt, Torkel

2005-06-01

SSI has pursued an international cooperation program since 1992 within the field of radiation protection and emergency preparedness for radiation accidents with the three Baltic countries as main beneficiaries. As the Baltic countries are members of the EU since May 2004, this bilateral support will now be phased out and replaced with other forms of cooperation. During the years passed, a large number of activities have been launched with a total budget of some 14 million ECU. The Baltic radiation protection authorities have played a big role in the cooperation and Baltic ministries, universities, nuclear technology installations and other industries using radiation have also been engaged in the projects. SKI, SKB, Studsvik and the Swedish nuclear power plants should be mentioned as major cooperation partners on the Swedish side. During autumn 2004 when such a large coordinated work program was coming to an end, SSI decided to hold a seminar with the purpose to follow up experiences from the work and discuss coming forms of cooperation. The seminar took place on the 18 of November 2004 and gathered some 80 participants, 29 of which from the Baltic countries. It was opened by Lars-Erik Holm, the SSI Director General, and the three Baltic countries then presented their views and impressions from the passed years of cooperation. The seminar was concluded with a panel discussion on 'How to proceed from today's situation'. The result was that SSI invited to a new coordination meeting during autumn 2005 to follow up and discuss coordination of radiation protection around the Baltic Sea together with the other Nordic radiation protection authorities.

Open quantum systems and the two-level atom interacting with a single mode of the electromagnetic field

International Nuclear Information System (INIS)

Sandulescu, A.; Stefanescu, E.

1987-07-01

On the basis of Lindblad theory of open quantum systems we obtain new optical equations for the system of two-level atom interacting with a single mode of the electromagnetic field. The conventional Block equations in a generalized form with field phases are obtained in the hypothesis that all the terms are slowly varying in the rotating frame.(authors)

Seismology: Ways and means for regional cooperation. Transparencies used during the presentation

International Nuclear Information System (INIS)

Menzhi, M.

1999-01-01

Within the frame of international cooperation in the field of CTBT, this paper describes the first seismologic station established in Morocco in 1934, and in sixties and seventies another 15 stations after the earthquake in Agadir. In 1982, a system for seismic detection was installed having as main objectives he following: coordination and correlation of activities concerned with evaluation of seismic risks in the Mediterranean region, and integration of geophysical data needed for seismic risk assessment

Inter-layer Cooper pairing of two-dimensional electrons

International Nuclear Information System (INIS)

Inoue, Masahiro; Takemori, Tadashi; Yoshizaki, Ryozo; Sakudo, Tunetaro; Ohtaka, Kazuo

1987-01-01

The authors point out the possibility that the high transition temperatures of the recently discovered oxide superconductors are dominantly caused by the inter-layer Cooper pairing of two-dimensional electrons that are coupled through the exchange of three-dimensional phonons. (author)

[Strategy Development for International Cooperation in the Clinical Laboratory Field].

Science.gov (United States)

Kudo, Yoshiko; Osawa, Susumu

2015-10-01

The strategy of international cooperation in the clinical laboratory field was analyzed to improve the quality of intervention by reviewing documents from international organizations and the Japanese government. Based on the world development agenda, the target of action for health has shifted from communicable diseases to non-communicable diseases (NCD). This emphasizes the importance of comprehensive clinical laboratories instead of disease-specific examinations in developing countries. To achieve this goal, the World Health Organization (WHO) has disseminated to the African and Asian regions the Laboratory Quality Management System (LQMS), which is based on the same principles of the International Organization of Standardization (ISO) 15189. To execute this strategy, international experts must have competence in project management, analyze information regarding the target country, and develop a strategy for management of the LQMS with an understanding of the technical aspects of laboratory work. However, there is no appropriate pre- and post-educational system of international health for Japanese international workers. Universities and academic organizations should cooperate with the government to establish a system of education for international workers. Objectives of this education system must include: (1) training for the organization and understanding of global health issues, (2) education of the principles regarding comprehensive management of clinical laboratories, and (3) understanding the LQMS which was employed based on WHO's initiative. Achievement of these objectives will help improve the quality of international cooperation in the clinical laboratory field.

Mean-field Ensemble Kalman Filter

KAUST Repository

Law, Kody

2015-01-07

A proof of convergence of the standard EnKF generalized to non-Gaussian state space models is provided. A density-based deterministic approximation of the mean-field limiting EnKF (MFEnKF) is proposed, consisting of a PDE solver and a quadrature rule. Given a certain minimal order of convergence between the two, this extends to the deterministic filter approximation, which is therefore asymptotically superior to standard EnKF for d < 2 . The fidelity of approximation of the true distribution is also established using an extension of total variation metric to random measures. This is limited by a Gaussian bias term arising from non-linearity/non-Gaussianity of the model, which arises in both deterministic and standard EnKF. Numerical results support and extend the theory.

Exact pairing correlations in one-dimensional trapped fermions with stochastic mean-field wave-functions

Energy Technology Data Exchange (ETDEWEB)

Juillet, O.; Gulminelli, F. [Caen Univ., Lab. de Physique Corpusculaire (LPC/ENSICAEN), 14 (France); Chomaz, Ph. [Grand Accelerateur National d' Ions Lourds (GANIL), 14 - Caen (France)

2003-11-01

The canonical thermodynamic properties of a one-dimensional system of interacting spin-1/2 fermions with an attractive zero-range pseudo-potential are investigated within an exact approach. The density operator is evaluated as the statistical average of dyadics formed from a stochastic mean-field propagation of independent Slater determinants. For an harmonically trapped Fermi gas and for fermions confined in a 1D-like torus, we observe the transition to a quasi-BCS state with Cooper-like momentum correlations and an algebraic long-range order. For few trapped fermions in a rotating torus, a dominant superfluid component with quantized circulation can be isolated. (author)

Residential exposures to indoor air pollutants could yield childhood leukemia risk levels similar to those associated with 60 Hz magnetic fields

International Nuclear Information System (INIS)

Easterly, C.E.

1992-01-01

Over a decade ago Easterly suggested that electromagnetic fields may be able to participate in a cooperative process leading to the expression of cancer. Evidence derived from the literature is presented to support the suggestion that potentially cooperative factors other than electromagnetic fields are present in homes in sufficient quantities to result in approximately the same risk levels as are being measured in epidemiology studies of childhood leukemia and electromagnetic fields. Generally these odds ratios vary from 1.5 to 2.5

Strategy for nuclear technical cooperation between Korea and U.S.A

International Nuclear Information System (INIS)

Kim, Kyoung Pyo; Kim, Young Min

1998-12-01

The Republic of Korea maintains joint coordination committee meeting in the field of nuclear technology with seven countries throughout the world. Among the committees, the R.O.K. - U.S.A. Joint Standing Committee on Nuclear Energy Cooperation (JSCNET) is regarded as one of the most active committees considering the long cooperative relationship relationship between the two countries. The cooperative programs between two countries range not only technical issues but also nuclear policy and safeguards endeavors. It is noted that at present there are eight items for co-operation in nuclear policy field, fourteen technical cooperation programs, thirteen safety related items for mutual co-operation, and six items for safeguards concerns. KAERI plays a key role in the implementation of joint cooperative programs as has been during the past. Among the various cooperative programs currently on-going, thirteen technical items and two safety programs are being initiated by KAERI. (author). 1 tab., 1 fig

Probing two-field open inflation by resonant signals in correlation functions

Energy Technology Data Exchange (ETDEWEB)

Battefeld, Thorsten; Niemeyer, Jens C.; Vlaykov, Dimitar, E-mail: tbattefe@astro.physik.uni-goettingen.de, E-mail: niemeyer@astro.physik.uni-goettingen.de, E-mail: vlaykov@astro.physik.uni-goettingen.de [Institute for Astrophysics, University of Goettingen, Friedrich Hund Platz 1, D-37077 Goettingen (Germany)

2013-05-01

We derive oscillatory signals in correlation functions in two-field open inflation by means of the in-in formalism; such signatures are caused by resonances between oscillations in the tunnelling field and fluctuations in the inflaton during the curvature dominated, intermediate and subsequent inflationary regime. While amplitudes are model-dependent, we find distinct oscillations in the power and bi-spectrum that can act as a direct probe of the curvature dominated phase and thus, indirectly, strengthen the claim of the string landscape if they were observed. We comment on the prospects of detecting these tell-tale signs in current experiments, which is challenging, but not impossible. At the technical level, we pay special attention to the applicability conditions for truncating fluctuations to the light (inflaton) field and derive upper limits on the oscillation amplitude of the heavy field. A violation of these bounds requires a multi-field analysis at the perturbed level.

A spectral k-means approach to bright-field cell image segmentation.

Science.gov (United States)

Bradbury, Laura; Wan, Justin W L

2010-01-01

Automatic segmentation of bright-field cell images is important to cell biologists, but difficult to complete due to the complex nature of the cells in bright-field images (poor contrast, broken halo, missing boundaries). Standard approaches such as level set segmentation and active contours work well for fluorescent images where cells appear as round shape, but become less effective when optical artifacts such as halo exist in bright-field images. In this paper, we present a robust segmentation method which combines the spectral and k-means clustering techniques to locate cells in bright-field images. This approach models an image as a matrix graph and segment different regions of the image by computing the appropriate eigenvectors of the matrix graph and using the k-means algorithm. We illustrate the effectiveness of the method by segmentation results of C2C12 (muscle) cells in bright-field images.

Nuclear energy and international cooperation

International Nuclear Information System (INIS)

Oshima, Keiichi

1981-01-01

There is no need to emphasize that nuclear energy cannot be developed without international cooperation at either the industrial or the academic level. In the meanwhile, there have been some marked political, economic and social changes in recent years which are posing constraints to the international cooperation in nuclear energy. The problems and constraints impeding nuclear power programs cannot be overcome by only one nation; international cooperation with common efforts to solve the problems is essential. Nuclear energy is different from fossil energy resources in that it is highly technology-intensive while others are resource-intensive. International cooperation in technology has an entirely different importance in the field of nuclear energy. Educational institutions will play a role in a new era of the international cooperation. (Mori, K.)

International Scientific Cooperation in the Field of Spatial Studies

Directory of Open Access Journals (Sweden)

Pavel Aleksandrovich Minakir

2014-06-01

Full Text Available The paper discusses the existing structure of international cooperation of scientific organizations in the field of regional studies in different parts of the world. The authors define current major organizations that coordinate the work of scientific subdivisions in the field of regional studies in the whole world and also in Europe, North and South America and the Asia-Pacific region. The researchers offer the new term - ‘public-scientific partnership’ (PSP - and discuss PSP mechanisms and its implementation ways that may strengthen regional scientific research in Russia. The authors also debate the idea of creation of the Russian Association of Regional Science

Communication and cooperation in networked environments: an experimental analysis.

Science.gov (United States)

Galimberti, C; Ignazi, S; Vercesi, P; Riva, G

2001-02-01

Interpersonal communication and cooperation do not happen exclusively face to face. In work contexts, as in private life, there are more and more situations of mediated communication and cooperation in which new online tools are used. However, understanding how to use the Internet to support collaborative interaction presents a substantial challenge for the designers and users of this emerging technology. First, collaborative Internet environments are designed to serve a purpose, so must be designed with intended users' tasks and goals explicitly considered. Second, in cooperative activities the key content of communication is the interpretation of the situations in which actors are involved. So, the most effective way of clarifying the meaning of messages is to connect them to a shared context of meaning. However, this is more difficult in the Internet than in other computer-based activities. This paper tries to understand the characteristics of cooperative activities in networked environments--shared 3D virtual worlds--through two different studies. The first used the analysis of conversations to explore the characteristics of the interaction during the cooperative task; the second analyzed whether and how the level of immersion in the networked environments influenced the performance and the interactional process. The results are analyzed to identify the psychosocial roots used to support cooperation in a digital interactive communication.

Does cooperation mean kinship between spatially discrete ant nests?

Science.gov (United States)

Procter, Duncan S; Cottrell, Joan E; Watts, Kevin; A'Hara, Stuart W; Hofreiter, Michael; Robinson, Elva J H

2016-12-01

Eusociality is one of the most complex forms of social organization, characterized by cooperative and reproductive units termed colonies. Altruistic behavior of workers within colonies is explained by inclusive fitness, with indirect fitness benefits accrued by helping kin. Members of a social insect colony are expected to be more closely related to one another than they are to other conspecifics. In many social insects, the colony can extend to multiple socially connected but spatially separate nests (polydomy). Social connections, such as trails between nests, promote cooperation and resource exchange, and we predict that workers from socially connected nests will have higher internest relatedness than those from socially unconnected, and noncooperating, nests. We measure social connections, resource exchange, and internest genetic relatedness in the polydomous wood ant Formica lugubris to test whether (1) socially connected but spatially separate nests cooperate, and (2) high internest relatedness is the underlying driver of this cooperation. Our results show that socially connected nests exhibit movement of workers and resources, which suggests they do cooperate, whereas unconnected nests do not. However, we find no difference in internest genetic relatedness between socially connected and unconnected nest pairs, both show high kinship. Our results suggest that neighboring pairs of connected nests show a social and cooperative distinction, but no genetic distinction. We hypothesize that the loss of a social connection may initiate ecological divergence within colonies. Genetic divergence between neighboring nests may build up only later, as a consequence rather than a cause of colony separation.

Entanglement and Other Nonclassical Properties of Two Two-Level Atoms Interacting with a Two-Mode Binomial Field: Constant and Intensity-Dependent Coupling Regimes

International Nuclear Information System (INIS)

Tavassoly, M.K.; Hekmatara, H.

2015-01-01

In this paper, we consider the interaction between two two-level atoms and a two-mode binomial field with a general intensity-dependent coupling regime. The outlined dynamical problem has explicit analytical solution, by which we can evaluate a few of its physical features of interest. To achieve the purpose of the paper, after choosing a particular nonlinearity function, we investigate the quantum statistics, atomic population inversion and at last the linear entropy of the atom-field system which is a good measure for the degree of entanglement. In detail, the effects of binomial field parameters, in addition to different initial atomic states on the temporal behavior of the mentioned quantities have been analyzed. The results show that, the values of binomial field parameters and the initial state of the two atoms influence on the nonclassical effects in the obtained states through which one can tune the nonclassicality criteria appropriately. Setting intensity-dependent coupling function equal to 1 reduces the results to the constant coupling case. By comparing the latter case with the nonlinear regime, we will observe that the nonlinearity disappears the pattern of collapse-revival phenomenon in the evolution of Mandel parameter and population inversion (which can be seen in the linear case with constant coupling), however, more typical collapse-revivals will be appeared for the cross-correlation function in the nonlinear case. Finally, in both linear and nonlinear regime, the entropy remains less than (but close to) 0.5. In other words the particular chosen nonlinearity does not critically affect on the entropy of the system. (paper)

Non-Hermitian wave packet approximation for coupled two-level systems in weak and intense fields

Energy Technology Data Exchange (ETDEWEB)

Puthumpally-Joseph, Raiju; Charron, Eric [Institut des Sciences Moléculaires d’Orsay (ISMO), CNRS, Univ. Paris-Sud, Université Paris-Saclay, F-91405 Orsay (France); Sukharev, Maxim [Science and Mathematics Faculty, College of Letters and Sciences, Arizona State University, Mesa, Arizona 85212 (United States)

2016-04-21

We introduce a non-Hermitian Schrödinger-type approximation of optical Bloch equations for two-level systems. This approximation provides a complete and accurate description of the coherence and decoherence dynamics in both weak and strong laser fields at the cost of losing accuracy in the description of populations. In this approach, it is sufficient to propagate the wave function of the quantum system instead of the density matrix, providing that relaxation and dephasing are taken into account via automatically adjusted time-dependent gain and decay rates. The developed formalism is applied to the problem of scattering and absorption of electromagnetic radiation by a thin layer comprised of interacting two-level emitters.

Realization of the mean-field universality class in spin-crossover materials

Science.gov (United States)

Miyashita, Seiji; Konishi, Yusuké; Nishino, Masamichi; Tokoro, Hiroko; Rikvold, Per Arne

2008-01-01

In spin-crossover materials, the volume of a molecule changes depending on whether it is in the high-spin (HS) or low-spin (LS) state. This change causes distortion of the lattice. Elastic interactions among these distortions play an important role for the cooperative properties of spin-transition phenomena. We find that the critical behavior caused by this elastic interaction belongs to the mean-field universality class, in which the critical exponents for the spontaneous magnetization and the susceptibility are β=1/2 and γ=1 , respectively. Furthermore, the spin-spin correlation function is a constant at long distances, and it does not show an exponential decay in contrast to short-range models. The value of the correlation function at long distances shows different size dependences: O(1/N) , O(1/N) , and constant for temperatures above, at, and below the critical temperature, respectively. The model does not exhibit clusters, even near the critical point. We also found that cluster growth is suppressed in the present model and that there is no critical opalescence in the coexistence region. During the relaxation process from a metastable state at the end of a hysteresis loop, nucleation phenomena are not observed, and spatially uniform configurations are maintained during the change of the fraction of HS and LS. These characteristics of the mean-field model are expected to be found not only in spin-crossover materials, but also generally in systems where elastic distortion mediates the interaction among local states.

Finite-State Mean-Field Games, Crowd Motion Problems, and its Numerical Methods

KAUST Repository

Machado Velho, Roberto

2017-09-10

In this dissertation, we present two research projects, namely finite-state mean-field games and the Hughes model for the motion of crowds. In the first part, we describe finite-state mean-field games and some applications to socio-economic sciences. Examples include paradigm shifts in the scientific community and the consumer choice behavior in a free market. The corresponding finite-state mean-field game models are hyperbolic systems of partial differential equations, for which we propose and validate a new numerical method. Next, we consider the dual formulation to two-state mean-field games, and we discuss numerical methods for these problems. We then depict different computational experiments, exhibiting a variety of behaviors, including shock formation, lack of invertibility, and monotonicity loss. We conclude the first part of this dissertation with an investigation of the shock structure for two-state problems. In the second part, we consider a model for the movement of crowds proposed by R. Hughes in [56] and describe a numerical approach to solve it. This model comprises a Fokker-Planck equation coupled with an Eikonal equation with Dirichlet or Neumann data. We first establish a priori estimates for the solutions. Next, we consider radial solutions, and we identify a shock formation mechanism. Subsequently, we illustrate the existence of congestion, the breakdown of the model, and the trend to the equilibrium. We also propose a new numerical method for the solution of Fokker-Planck equations and then to systems of PDEs composed by a Fokker-Planck equation and a potential type equation. Finally, we illustrate the use of the numerical method both to the Hughes model and mean-field games. We also depict cases such as the evacuation of a room and the movement of persons around Kaaba (Saudi Arabia).

Relativistic Chiral Mean Field Model for Finite Nuclei

Science.gov (United States)

Ogawa, Y.; Toki, H.; Tamenaga, S.; Haga, A.

2009-08-01

We present a relativistic chiral mean field (RCMF) model, which is a method for the proper treatment of pion-exchange interaction in the nuclear many-body problem. There the dominant term of the pionic correlation is expressed in two-particle two-hole (2p-2h) states with particle-holes having pionic quantum number, J^{π}. The charge-and-parity-projected relativistic mean field (CPPRMF) model developed so far treats surface properties of pionic correlation in 2p-2h states with J^{π} = 0^{-} (spherical ansatz). We extend the CPPRMF model by taking 2p-2h states with higher spin quantum numbers, J^{π} = 1^{+}, 2^{-}, 3^{+}, ... to describe the full strength of the pionic correlation in the intermediate range (r > 0.5 fm). We apply the RCMF model to the ^{4}He nucleus as a pilot calculation for the study of medium and heavy nuclei. We study the behavior of energy convergence with the pionic quantum number, J^{π}, and find convergence around J^{π}_{max} = 6^{-}. We include further the effect of the short-range repulsion in terms of the unitary correlation operator method (UCOM) for the central part of the pion-exchange interaction. The energy contribution of about 50% of the net two-body interaction comes from the tensor part and 20% comes from the spin-spin central part of the pion-exchange interaction.}

Population structure induces a symmetry breaking favoring the emergence of cooperation.

Directory of Open Access Journals (Sweden)

Jorge M Pacheco

2009-12-01

Full Text Available The evolution of cooperation described in terms of simple two-person interactions has received considerable attention in recent years, where several key results were obtained. Among those, it is now well established that the web of social interaction networks promotes the emergence of cooperation when modeled in terms of symmetric two-person games. Up until now, however, the impacts of the heterogeneity of social interactions into the emergence of cooperation have not been fully explored, as other aspects remain to be investigated. Here we carry out a study employing the simplest example of a prisoner's dilemma game in which the benefits collected by the participants may be proportional to the costs expended. We show that the heterogeneous nature of the social network naturally induces a symmetry breaking of the game, as contributions made by cooperators may become contingent on the social context in which the individual is embedded. A new, numerical, mean-field analysis reveals that prisoner's dilemmas on networks no longer constitute a defector dominance dilemma--instead, individuals engage effectively in a general coordination game. We find that the symmetry breaking induced by population structure profoundly affects the evolutionary dynamics of cooperation, dramatically enhancing the feasibility of cooperators: cooperation blooms when each cooperator contributes the same cost, equally shared among the plethora of games in which she participates. This work provides clear evidence that, while individual rational reasoning may hinder cooperative actions, the intricate nature of social interactions may effectively transform a local dilemma of cooperation into a global coordination problem.

Rigorous derivation of the mean-field green functions of the two-band Hubbard model of superconductivity

International Nuclear Information System (INIS)

Adam, G.; Adam, S.

2007-01-01

The Green function (GF) equation of motion technique for solving the effective two-band Hubbard model of high-T c superconductivity in cuprates rests on the Hubbard operator (HO) algebra. We show that, if we take into account the invariance to translations and spin reversal, the HO algebra results in invariance properties of several specific correlation functions. The use of these properties allows rigorous derivation and simplification of the expressions of the frequency matrix (FM) and of the generalized mean-field approximation (GMFA) Green functions (GFs) of the model. For the normal singlet hopping and anomalous exchange pairing correlation functions which enter the FM and GMFA-GFs, the use of spectral representations allows the identification and elimination of exponentially small quantities. This procedure secures the reduction of the correlation order to the GMFA-GF expressions

International co-operation in the nuclear field - past, present and prospects

International Nuclear Information System (INIS)

Goldschmidt, B.

1978-01-01

On the occasion of the 20th anniversary of its creation, the Nuclear Energy Agency of the Organization for Economic Co-operation and Development (NEA/OECD) held a symposium in Paris on 1 and 2 February 1978. Some 200 participants from the 23 Member countries of the NEA as well as representatives of the Commission of European Communities, FORATOM and the IAEA attended the symposium. At a panel discussion at the symposium, led by Dr. Sigvard Eklund, Director General of the IAEA, the future of international co-operation between advanced nations in the nuclear field was discussed. While recognizing that nuclear energy is at present going through a period of uncertainty pending resolution of the intertwined problems of gaining public confidence and of non-proliferation, the panel expressed its strong confidence in the future of nuclear power, and the vital contribution it would make, particularly between now and the end of the century. During the meeting, a critical review was made of the way in which international co-operation has evolved since the early stages of peaceful nuclear development, and of the influence on this co-operation of the changing relationship between government and industry. The contribution of international co-operation - and its limitations - was carefully scrutinized, notably in the crucial area of the nuclear fuel cycle

Transformative State Capacity in Post-Collective China: The Introduction of the New Rural Cooperative Medical System in Two Counties of Western China, 2006-2008.

Science.gov (United States)

Klotzbücher, Sascha; Lässig, Peter

2009-06-01

In 2002, the Chinese leadership announced a turnaround in national welfare policy: Local insurance at county level, called the New Rural Cooperative Medical System (NRCMS), was to cover all counties by 2010. This paper addresses the main characteristics of NRCMS as an example of 'transformative state capacity' in decentralised policy fields and its feature 'responsiveness' as a market-based means of its introduction.Reviewing the modes of governance and comparing the introduction of local schemes based on two case studies of western China since 2006, this paper argues that the flexibility shown by local administrators in considering structural and procedural adjustments is the result not only of central directives but also of local initiatives. Forms of locally embedded responsiveness to the needs and perceptions of health care recipients are crucial in enhancing the accountability and responsiveness of local cadres. These new modes of 'responsiveness' or responsive regulation are important in understanding and conceptualising the transformative state capacity. Responsive settings using centrally defined local feedback loops are different from hierarchical control and the formal institutionalised representation of the interests of the local population, and are a rough but effective means of enhancing both flexibility and the efficiency of control and financing by the central state. These feedback loops, which are based on voluntary enrolment and on central state subsidies made dependent on contributions received from participants and local government, are complementary forms of governance at grassroots level.

Optimization of potential field method parameters through networks for swarm cooperative manipulation tasks

Directory of Open Access Journals (Sweden)

Rocco Furferi

2016-10-01

Full Text Available An interesting current research field related to autonomous robots is mobile manipulation performed by cooperating robots (in terrestrial, aerial and underwater environments. Focusing on the underwater scenario, cooperative manipulation of Intervention-Autonomous Underwater Vehicles (I-AUVs is a complex and difficult application compared with the terrestrial or aerial ones because of many technical issues, such as underwater localization and limited communication. A decentralized approach for cooperative mobile manipulation of I-AUVs based on Artificial Neural Networks (ANNs is proposed in this article. This strategy exploits the potential field method; a multi-layer control structure is developed to manage the coordination of the swarm, the guidance and navigation of I-AUVs and the manipulation task. In the article, this new strategy has been implemented in the simulation environment, simulating the transportation of an object. This object is moved along a desired trajectory in an unknown environment and it is transported by four underwater mobile robots, each one provided with a seven-degrees-of-freedom robotic arm. The simulation results are optimized thanks to the ANNs used for the potentials tuning.

Vector solution for the mean electromagnetic fields in a layer of random particles

Science.gov (United States)

Lang, R. H.; Seker, S. S.; Levine, D. M.

1986-01-01

The mean electromagnetic fields are found in a layer of randomly oriented particles lying over a half space. A matrix-dyadic formulation of Maxwell's equations is employed in conjunction with the Foldy-Lax approximation to obtain equations for the mean fields. A two variable perturbation procedure, valid in the limit of small fractional volume, is then used to derive uncoupled equations for the slowly varying amplitudes of the mean wave. These equations are solved to obtain explicit expressions for the mean electromagnetic fields in the slab region in the general case of arbitrarily oriented particles and arbitrary polarization of the incident radiation. Numerical examples are given for the application to remote sensing of vegetation.

Levels of Literary Meaning

DEFF Research Database (Denmark)

Klausen, Søren Harnow

2017-01-01

I argue that intentionalist theories of meaning and interpretation, like those of Hirsch and Juhl, have been insufficiently attentive to the different levels of authorial intention that are operative in literary works. By countenancing intentions on different levels – ranging from simple semantic...

Effective masses and the nuclear mean field

International Nuclear Information System (INIS)

Mahaux, C.; Sartor, R.

1985-01-01

The effective mass characterizes the energy dependence of the empirical average nuclear potential. This energy dependence has two different sources, namely the nonlocality in space of the microscopic mean field on the one hand, and its true energy dependence on the other hand. Correspondingly it is convenient to divide the effective mass into two components, the k-mass and the ω-mass. The latter is responsible for the existence of a peak in the energy dependence of the effective mass. This peak is located near the Fermi energy in nuclear matter and in nuclei, as well as in the electron gas, the hard sphere Fermi gas and liquid helium 3. A related phenomenon is the existence of a low energy anomaly in the energy dependence of the optical model potential between two heavy ions. (orig.)

Regularity theory for mean-field game systems

CERN Document Server

Gomes, Diogo A; Voskanyan, Vardan

2016-01-01

Beginning with a concise introduction to the theory of mean-field games (MFGs), this book presents the key elements of the regularity theory for MFGs. It then introduces a series of techniques for well-posedness in the context of mean-field problems, including stationary and time-dependent MFGs, subquadratic and superquadratic MFG formulations, and distinct classes of mean-field couplings. It also explores stationary and time-dependent MFGs through a series of a-priori estimates for solutions of the Hamilton-Jacobi and Fokker-Planck equation. It shows sophisticated a-priori systems derived using a range of analytical techniques, and builds on previous results to explain classical solutions. The final chapter discusses the potential applications, models and natural extensions of MFGs. As MFGs connect common problems in pure mathematics, engineering, economics and data management, this book is a valuable resource for researchers and graduate students in these fields.

Regularity Theory for Mean-Field Game Systems

KAUST Repository

Gomes, Diogo A.

2016-09-14

Beginning with a concise introduction to the theory of mean-field games (MFGs), this book presents the key elements of the regularity theory for MFGs. It then introduces a series of techniques for well-posedness in the context of mean-field problems, including stationary and time-dependent MFGs, subquadratic and superquadratic MFG formulations, and distinct classes of mean-field couplings. It also explores stationary and time-dependent MFGs through a series of a-priori estimates for solutions of the Hamilton-Jacobi and Fokker-Planck equation. It shows sophisticated a-priori systems derived using a range of analytical techniques, and builds on previous results to explain classical solutions. The final chapter discusses the potential applications, models and natural extensions of MFGs. As MFGs connect common problems in pure mathematics, engineering, economics and data management, this book is a valuable resource for researchers and graduate students in these fields.

Regularity Theory for Mean-Field Game Systems

KAUST Repository

Gomes, Diogo A.; Pimentel, Edgard A.; Voskanyan, Vardan K.

2016-01-01

Beginning with a concise introduction to the theory of mean-field games (MFGs), this book presents the key elements of the regularity theory for MFGs. It then introduces a series of techniques for well-posedness in the context of mean-field problems, including stationary and time-dependent MFGs, subquadratic and superquadratic MFG formulations, and distinct classes of mean-field couplings. It also explores stationary and time-dependent MFGs through a series of a-priori estimates for solutions of the Hamilton-Jacobi and Fokker-Planck equation. It shows sophisticated a-priori systems derived using a range of analytical techniques, and builds on previous results to explain classical solutions. The final chapter discusses the potential applications, models and natural extensions of MFGs. As MFGs connect common problems in pure mathematics, engineering, economics and data management, this book is a valuable resource for researchers and graduate students in these fields.

The history and perspective of Romania-USA cooperation in the field of technologic transfer of TRIGA reactor concept

International Nuclear Information System (INIS)

Ciocaanescu, M.; Ionescu, M.

1996-01-01

The cooperation between Romania and the USA in the field of technologic transfer of nuclear research reactor technology began with the steady state 14 MW t TRIGA reactor, installed at INR Pitesti, Romania. It is the first in the range of TRIGA reactors proposed as a materials testing reactor. The first criticality was reached in November 19, 1979 and first operation at 14 MW t level was in February 1980. The paper will present the short history of this cooperation and the perspective for a new cooperation for building a Nuclear Heating Plant using the TRIGA reactor concept for demonstration purpose. The energy crisis is a world-wide problem which affects each country in different ways because the resources and the consumption are unfairly distributed. World-wide research points out that the fossil fuel sources are not to be considered the main energy sources for the long term as they are limited

Justification and choice of hardware for automatic control system by technical means at the garage consumer cooperative

Directory of Open Access Journals (Sweden)

Krasnykh V.Yu.

2017-06-01

Full Text Available the article describes the main system requirements of software of finished products for implementation of an automatic control system by technical means at the garage consumer cooperative.

Mean Field Games with a Dominating Player

Energy Technology Data Exchange (ETDEWEB)

Bensoussan, A., E-mail: axb046100@utdallas.edu [The University of Texas at Dallas, International Center for Decision and Risk Analysis, Jindal School of Management (United States); Chau, M. H. M., E-mail: michaelchaumanho@gmail.com; Yam, S. C. P., E-mail: scpyam@sta.cuhk.edu.hk [The Chinese University of Hong Kong, Department of Statistics (Hong Kong, People’s Republic of China) (China)

2016-08-15

In this article, we consider mean field games between a dominating player and a group of representative agents, each of which acts similarly and also interacts with each other through a mean field term being substantially influenced by the dominating player. We first provide the general theory and discuss the necessary condition for the optimal controls and equilibrium condition by adopting adjoint equation approach. We then present a special case in the context of linear-quadratic framework, in which a necessary and sufficient condition can be asserted by stochastic maximum principle; we finally establish the sufficient condition that guarantees the unique existence of the equilibrium control. The proof of the convergence result of finite player game to mean field counterpart is provided in Appendix.

Band mixing effects in mean field theories

International Nuclear Information System (INIS)

Kuyucak, S.; Morrison, I.

1989-01-01

The 1/N expansion method, which is an angular momentum projected mean field theory, is used to investigate the nature of electromagnetic transitions in the interacting boson model (IBM). Conversely, comparison with the exact IBM results sheds light on the range of validity of the mean field theory. It is shown that the projected mean field results for the E2 transitions among the ground, β and γ bands are incomplete for the spin dependent terms and it is essential to include band mixing effect for a correct (Mikhailov) analysis of E2 data. The algebraic expressions derived are general and will be useful in the analysis of experimental data in terms of both the sd and sdg boson models. 17 refs., 7 figs., 8 tabs

Evolutionary Fuzzy Control and Navigation for Two Wheeled Robots Cooperatively Carrying an Object in Unknown Environments.

Science.gov (United States)

Juang, Chia-Feng; Lai, Min-Ge; Zeng, Wan-Ting

2015-09-01

This paper presents a method that allows two wheeled, mobile robots to navigate unknown environments while cooperatively carrying an object. In the navigation method, a leader robot and a follower robot cooperatively perform either obstacle boundary following (OBF) or target seeking (TS) to reach a destination. The two robots are controlled by fuzzy controllers (FC) whose rules are learned through an adaptive fusion of continuous ant colony optimization and particle swarm optimization (AF-CACPSO), which avoids the time-consuming task of manually designing the controllers. The AF-CACPSO-based evolutionary fuzzy control approach is first applied to the control of a single robot to perform OBF. The learning approach is then applied to achieve cooperative OBF with two robots, where an auxiliary FC designed with the AF-CACPSO is used to control the follower robot. For cooperative TS, a rule for coordination of the two robots is developed. To navigate cooperatively, a cooperative behavior supervisor is introduced to select between cooperative OBF and cooperative TS. The performance of the AF-CACPSO is verified through comparisons with various population-based optimization algorithms for the OBF learning problem. Simulations and experiments verify the effectiveness of the approach for cooperative navigation of two robots.

Conserving gapless mean-field theory for weakly interacting Bose gases

International Nuclear Information System (INIS)

Kita, Takafumi

2006-01-01

This paper presents a conserving gapless mean-field theory for weakly interacting Bose gases. We first construct a mean-field Luttinger-Ward thermodynamic functional in terms of the condensate wave function Ψ and the Nambu Green's function G for the quasiparticle field. Imposing its stationarity respect to Ψ and G yields a set of equations to determine the equilibrium for general non-uniform systems. They have a plausible property of satisfying the Hugenholtz-Pines theorem to provide a gapless excitation spectrum. Also, the corresponding dynamical equations of motion obey various conservation laws. Thus, the present mean-field theory shares two important properties with the exact theory: 'conserving' and 'gapless'. The theory is then applied to a homogeneous weakly interacting Bose gas with s-wave scattering length a and particle mass m to clarify its basic thermodynamic properties under two complementary conditions of constant density n and constant pressure p. The superfluid transition is predicted to be first-order because of the non-analytic nature of the order-parameter expansion near T c inherent in Bose systems, i.e., the Landau-Ginzburg expansion is not possible here. The transition temperature T c shows quite a different interaction dependence between the n-fixed and p-fixed cases. In the former case T c increases from the ideal gas value T 0 as T c /T 0 =1+2.33an 1/3 , whereas it decreases in the latter as T c /T 0 =1-3.84a(mp/2πℎ 2 ) 1/5 . Temperature dependences of basic thermodynamic quantities are clarified explicitly. (author)

From cooperation to globalization

Directory of Open Access Journals (Sweden)

Gabriela UNGUREANU

2010-09-01

Full Text Available Globalization is seen as a consequence of cross-border business. This complex and irreversible process can be seen as an extension of capitalist relations of production or increased interdependence in the economic system. Globalization has given rise to more and more fields of activity worldwide. To meet the challenges of business globalization, many companies form strategic alliances, cooperate or merge with other companies. Cooperation is seen by many companies as an alternative path to success. In recent years joint international associations, licensing, co-production agreements, joint research programs, exploration of consortia and other cooperative relationships between two or more corporations with potential have increased. We notice a cooperation tendency among small-sized companies, especially among those from the developing countries.

Statistical fluctuations in cooperative cyclotron radiation

Science.gov (United States)

Anishchenko, S. V.; Baryshevsky, V. G.

2018-01-01

Shot noise is the cause of statistical fluctuations in cooperative cyclotron radiation generated by an ensemble of electrons oscillating in magnetic field. Autophasing time - the time required for the cooperative cyclotron radiation power to peak - is the critical parameter characterizing the dynamics of electron-oscillators interacting via the radiation field. It is shown that premodulation of charged particles leads to a considerable narrowing of the autophasing time distribution function for which the analytic expression is obtained. When the number of particles Ne exceeds a certain value that depends on the degree to which the particles have been premodulated, the relative root-mean-square deviation (RMSD) of the autophasing time δT changes from a logarithmic dependence on Ne (δT ∼ 1 / lnNe) to square-root (δT ∼ 1 /√{Ne }). A slight energy spread (∼4%) results in a twofold drop of the maximum attainable power of cooperative cyclotron radiation.

Energy Efficient Four Level Cooperative Opportunistic Communication for Wireless Personal Area Networks (WPAN)

DEFF Research Database (Denmark)

Rohokale, Vandana M.; Inamdar, Sandeep; Prasad, Neeli R.

2013-01-01

For wireless sensor networks (WSN),energy is a scarce resource. Due to limited battery resources, the energy consumption is the critical issue for the transmission as well as reception of the signals in the wireless communication. WSNs are infrastructure-less shared network demanding more energy...... consumption due to collaborative transmissions. This paper proposes a new cooperative opportunistic four level model for IEEE 802.15.4 Wireless Personal Area Network (WPAN).The average per node energy consumption is observed merely about 0.17mJ for the cooperative wireless communication which proves...... the proposed mechanism to be energy efficient. This paper further proposes four levels of cooperative data transmission from source to destination to improve network coverage with energy efficiency....

Adaptive co-evolution of strategies and network leading to optimal cooperation level in spatial prisoner's dilemma game

International Nuclear Information System (INIS)

Han-Shuang, Chen; Zhong-Huai, Hou; Hou-Wen, Xin; Ji-Qian, Zhang

2010-01-01

We study evolutionary prisoner's dilemma game on adaptive networks where a population of players co-evolves with their interaction networks. During the co-evolution process, interacted players with opposite strategies either rewire the link between them with probability p or update their strategies with probability 1 – p depending on their payoffs. Numerical simulation shows that the final network is either split into some disconnected communities whose players share the same strategy within each community or forms a single connected network in which all nodes are in the same strategy. Interestingly, the density of cooperators in the final state can be maximised in an intermediate range of p via the competition between time scale of the network dynamics and that of the node dynamics. Finally, the mean-field analysis helps to understand the results of numerical simulation. Our results may provide some insight into understanding the emergence of cooperation in the real situation where the individuals' behaviour and their relationship adaptively co-evolve. (general)

Back-reaction beyond the mean field approximation

International Nuclear Information System (INIS)

Kluger, Y.

1993-01-01

A method for solving an initial value problem of a closed system consisting of an electromagnetic mean field and its quantum fluctuations coupled to fermions is presented. By tailoring the large N f expansion method to the Schwinger-Keldysh closed time path (CTP) formulation of the quantum effective action, causality of the resulting equations of motion is ensured, and a systematic energy conserving and gauge invariant expansion about the electromagnetic mean field in powers of 1/N f is developed. The resulting equations may be used to study the quantum nonequilibrium effects of pair creation in strong electric fields and the scattering and transport processes of a relativistic e + e - plasma. Using the Bjorken ansatz of boost invariance initial conditions in which the initial electric mean field depends on the proper time only, we show numerical results for the case in which the N f expansion is truncated in the lowest order, and compare them with those of a phenomenological transport equation

Non-cooperative game theory

CERN Document Server

Fujiwara-Greve, Takako

2015-01-01

This is a textbook for university juniors, seniors, and graduate students majoring in economics, applied mathematics, and related fields. Each chapter is structured so that a core concept of that chapter is presented with motivations, useful applications are given, and related advanced topics are discussed for future study. Many helpful exercises at various levels are provided at the end of each chapter. Therefore, this book is most suitable for readers who intend to study non-cooperative game theory rigorously for both theoretical studies and applications. Game theory consists of non-cooperative games and cooperative games. This book covers only non-cooperative games, which are major tools used in current economics and related areas. Non-cooperative game theory aims to provide a mathematical prediction of strategic choices by decision makers (players) in situations of conflicting interest. Through the logical analyses of strategic choices, we obtain a better understanding of social (economic, business) probl...

Fictive impurity approach to dynamical mean field theory

Energy Technology Data Exchange (ETDEWEB)

Fuhrmann, A.

2006-10-15

A new extension of the dynamical mean-field theory was investigated in the regime of large Coulomb repulsion. A number of physical quantities such as single-particle density of states, spin-spin correlation, internal energy and Neel temperature, were computed for a two-dimensional Hubbard model at half-filling. The numerical data were compared to our analytical results as well as to the results computed using the dynamical cluster approximation. In the second part of this work we consider a two-plane Hubbard model. The transport properties of the bilayer were investigated and the phase diagram was obtained. (orig.)

Fictive impurity approach to dynamical mean field theory

International Nuclear Information System (INIS)

Fuhrmann, A.

2006-10-01

A new extension of the dynamical mean-field theory was investigated in the regime of large Coulomb repulsion. A number of physical quantities such as single-particle density of states, spin-spin correlation, internal energy and Neel temperature, were computed for a two-dimensional Hubbard model at half-filling. The numerical data were compared to our analytical results as well as to the results computed using the dynamical cluster approximation. In the second part of this work we consider a two-plane Hubbard model. The transport properties of the bilayer were investigated and the phase diagram was obtained. (orig.)

New cooperative mechanisms of low-energy nuclear reactions using super low-energy external field

International Nuclear Information System (INIS)

Gareev, F.A.; Zhidkova, I.E.

2006-01-01

We propose a new mechanism of LENR: cooperative processes in the whole system, nuclei + atoms + condensed matter, can occur at a smaller threshold energies than the corresponding ones on free constituents. The cooperative processes can be induced and enhanced by low-energy external fields. The excess heat is the emission of internal energy and transmutations at LENR are the result of redistribution of inner energy of the whole system. (author)

New Cooperative Mechanisms of Low-Energy Nuclear Reactions Using Super Low-Energy External Field

Science.gov (United States)

Gareev, F. A.; Zhidkova, I. E.

We propose a new mechanism of LENR: cooperative processes in the whole system, nuclei + atoms + condensed matter, can occur at a smaller threshold energies than the corresponding ones on free constituents. The cooperative processes can be induced and enhanced by low-energy external fields. The excess heat is the emission of internal energy and transmutations at LENR are the result of redistribution of inner energy of the whole system.

Mean Field Theory, Ginzburg Criterion, and Marginal Dimensionality of Phase-Transitions

DEFF Research Database (Denmark)

Als-Nielsen, Jens Aage; Birgenau, R. J.

1977-01-01

By applying a real space version of the Ginzburg criterion, the role of fluctuations and thence the self‐consistency of mean field theory are assessed in a simple fashion for a variety of phase transitions. It is shown that in using this approach the concept of ’’marginal dimensionality’’ emerges...... in a natural way. For example, it is shown that for many homogeneous structural transformations the marginal dimensionality is two, so that mean field theory will be valid for real three‐dimensional systems. It is suggested that this simple self‐consistent approach to Landau theory should be incorporated...

Ohm's law for mean magnetic fields

International Nuclear Information System (INIS)

Boozer, A.H.

1986-05-01

The magnetic fields associated with plasmas frequently exhibit small amplitude MHD fluctuations. It is useful to have equations for the magnetic field averaged over these fluctuations, the so-called mean field equations. Under very general assumptions it is shown that the effect of MHD fluctuations on a force-free plasma can be represented by one parameter in Ohm's law, which is effectively the coefficient of electric current viscosity

Ohm's law for mean magnetic fields

International Nuclear Information System (INIS)

Boozer, A.H.

1986-01-01

The magnetic fields associated with plasmas frequently exhibit small-amplitude MHD fluctuations. It is useful to have equations for the magnetic field averaged over these fluctuations, the so-called mean field equations. Under very general assumptions, it is shown that the effect of MHD fluctuations on a force-free plasma can be represented by one parameter in Ohm's law, which is effectively the coefficient of electric current viscosity. (author)

Cooperative and networking strategies in small business

CERN Document Server

Ferreira, João

2017-01-01

The book aims to collect the most recent research and best practices in the cooperative and networking small business field identifying new theoretical models and describing the relationship between cooperation and networks in the small business strategy context. It examines different concepts and analytical techniques better understand the links between cooperative strategies and networks in small business. It also studies the existing economic conditions of network and strategic implications to small business from the point of view of their internal and external consistency. Cooperation and networks is a fashionable topic. It is receiving increasing attention in popular management publications, as well as specialized academic journals. Cooperation between firms and industries is a means of leveraging and aggregating knowledge also generating direct benefits in terms of innovation, productivity and competitiveness. Various options and decisions made within the framework of strategic alliances may be identifi...

A water-budget approach to estimating potential groundwater recharge from two domestic sewage disposal fields in eastern Bernalillo County, New Mexico, 2011-12

Science.gov (United States)

Crilley, Dianna M.; Collison, Jake W.

2015-08-04

Eastern Bernalillo County, New Mexico, is a historically rural area that in recent years has experienced an increase in population and in the construction of new housing units, most of which are not connected to a centralized wastewater treatment system. Increasing water use has raised concerns about the effect of development on the available groundwater resources in the area. During 2011–12, the U.S. Geological Survey, in cooperation with Bernalillo County Public Works Natural Resource Services, used a water-budget approach to quantify the amount of potential groundwater recharge occurring from the domestic sewage (effluent) dosed to the sewage disposal field at two locations—sites A and B—in eastern Bernalillo County, N. Mex. The amount of effluent that is potentially available for groundwater recharge was determined as the mean daily volume of effluent dosed to the disposal field in excess of the mean daily volume of effluent loss from evapotranspiration from the disposal field.

New Aspects of Field Entropy Squeezing as an Indicator for Mixed State Entanglement in an Effective Two-Level System with Stark Shift

Institute of Scientific and Technical Information of China (English)

S.Abdel-Khalek; M.M.A.Ahmed; A-S F.Obada

2011-01-01

We present an effective two-level system in interaction through two-photon processes with a single mode quantized electromagnetic field,initially prepared in a coherent state.Field entropy squeezing as an indicator of the entanglement in a mixed state system is suggested.The temporal evolution of the negativity,Wehrl entropy,Wehrl phase distribution and field entropy squeezing are investigated.The results highlight the important roles played by both the Stark shift parameters and the mixed state setting in the dynamics of the Wehrl entropy,Wehrl phase distribution and field entropy squeezing.%We present an effective two-level system in interaction through two-photon processes with a single mode quantized electromagnetic Reid, initially prepared in a coherent state. Field entropy squeezing as an indicator of the entanglement in a mixed state system is suggested. The temporal evolution of the negativity, Wehrl entropy, Wehrl phase distribution and field entropy squeezing are investigated. The results highlight the important roles played by both the Stark shift parameters and the mixed state setting in the dynamics of the Wehrl entropy, Wehrl phase distribution and field entropy squeezing.

Evolution of the field quantum entropy and entanglement in a system of multimode light field interacting resonantly with a two-level atom through N_j-degenerate N~Σ-photon process

Institute of Scientific and Technical Information of China (English)

2008-01-01

The time evolution of the field quantum entropy and entanglement in a system of multi-mode coherent light field resonantly interacting with a two-level atom by de-generating the multi-photon process is studied by utilizing the Von Neumann re-duced entropy theory,and the analytical expressions of the quantum entropy of the multimode field and the numerical calculation results for three-mode field inter-acting with the atom are obtained. Our attention focuses on the discussion of the influences of the initial average photon number,the atomic distribution angle and the phase angle of the atom dipole on the evolution of the quantum field entropy and entanglement. The results obtained from the numerical calculation indicate that: the stronger the quantum field is,the weaker the entanglement between the quan-tum field and the atom will be,and when the field is strong enough,the two sub-systems may be in a disentangled state all the time; the quantum field entropy is strongly dependent on the atomic distribution angle,namely,the quantum field and the two-level atom are always in the entangled state,and are nearly stable at maximum entanglement after a short time of vibration; the larger the atomic dis-tribution angle is,the shorter the time for the field quantum entropy to evolve its maximum value is; the phase angles of the atom dipole almost have no influences on the entanglement between the quantum field and the two-level atom. Entangled states or pure states based on these properties of the field quantum entropy can be prepared.

Mean-field Ensemble Kalman Filter

KAUST Repository

Law, Kody; Tembine, Hamidou; Tempone, Raul

2015-01-01

A proof of convergence of the standard EnKF generalized to non-Gaussian state space models is provided. A density-based deterministic approximation of the mean-field limiting EnKF (MFEnKF) is proposed, consisting of a PDE solver and a quadrature

Quantum correlations between each two-level system in a pair of atoms and general coherent fields

Directory of Open Access Journals (Sweden)

S. Abdel-Khalek

Full Text Available The quantitative description of the quantum correlations between each two-level system in a two-atom system and the coherent fields initially defined in a coherent state in the framework of power-law potentials (PLPCSs is considered. Specifically, we consider two atoms locally interacting with PLPCSs and take into account the different terms of interactions, the entanglement and quantum discord are studied including the time-dependent coupling and photon transition effects. Using the monogamic relation between the entanglement of formation and quantum discord in tripartite systems, we show that the control and preservation of the different kinds of quantum correlations greatly benefit from the combination of the choice of the physical quantities. Finally, we explore the link between the dynamical behavior of quantum correlations and nonclassicality of the fields with and without atomic motion effect. Keywords: Quantum correlations, Monogamic relation, Coherent states, Power-law potentials, Wehrl entropy

Institutional and scientific co-operation, networking and capacity building in the field of food safety and quality

NARCIS (Netherlands)

Boekel, van M.A.J.S.; Meerdink, G.; Banati, D.; Marvin, H.J.P.; Kuiper, H.A.; Houtman, C.B.

2002-01-01

This paper explains the situation in Hungary and The Netherlands regarding scientific co-operation, networking and capacity building in the field of food quality and safety. Specific details are given about institutional co-operation including exchanges between staff and students, collaborative

International cooperative research with Japan for the establishment of cooperation structure and technology for dynamic neutron radiography using HANARO

International Nuclear Information System (INIS)

Lim, I. C.; Sim, C. M.; Lee, B. H.; Choi, Y. S.; Baek, W. P.; Cha, J. E.; Yoon, B. J.; Chu, I. C.

2007-07-01

DNR is the technique to obtain radiography image continuously using a imaging system and Japan is the leading country in this field. Considering that no research has been performed to obtain quantitative parameters using DNR in Korea, it was necessary to establish a cooperative structure with Japanese experts and to develop the DNR technique throughout this project. The objectives of the project were to conduct 4 cooperative experiments using the HANARO BNCT facility and to establish a relationship with Japanese experts which makes it possible to maintain continuous communication. 4 experiments such as the void fraction and flow pattern measurement in a channel simulating HANARO fuel channel, observation of flow field in Pb/Bi field and the observation of cavity in a diesel engine nozzle were successfully completed. Also, the continuos communication and cooperation between the experts of two countries will be made. In this sense, this project is believed as a model project to use the mega research facility such as HANARO for the international cooperation

Considering individual satisfaction levels enhances cooperation in a spatial prisoner’s dilemma game

International Nuclear Information System (INIS)

Tanimoto, Jun

2015-01-01

Highlights: • A new model for the SPD game considering an individual’s satisfaction level is presented. • Simulation results show a non-trivial enhancement of cooperation. • The enhancement found results from a stochastic resonance effect. - Abstract: Based on the observance in human society, the satisfaction level of an individual as a result of an obtained payoff depends on personal tendency to some extent; we establish a new model for spatial prisoner’s dilemma games. We describe individual satisfaction as a stochastically deviated value around each of the four payoffs stipulated by a payoff matrix, which is maintained throughout the life of a certain agent. When strategy updating, an agent who refers to his own satisfaction level cannot see neighbors’ satisfaction levels but can only observe neighbors’ accumulated payoffs. By varying the update rule and underlying topology, we perform numerical simulations that reveal cooperation is significantly enhanced by this change. We argue that this enhancement of cooperation is analogous to a stochastic resonance effect, like the payoff noise effects Perc (2006).

Energy efficiency: From regional to global cooperation

International Nuclear Information System (INIS)

Brendow, K.

1994-01-01

In developing, reforming and emerging countries in particular, institutional hurdles have hindered the introduction of energy efficient technology. The author develops the theme from two U.N. projects: A new institutional accessibility to supra-regional cooperation could provide an important stimulus for future worldwide cooperation in the field of energy efficiency. (orig.) [de

Phase transitions in cooperative coinfections: Simulation results for networks and lattices

Science.gov (United States)

Grassberger, Peter; Chen, Li; Ghanbarnejad, Fakhteh; Cai, Weiran

2016-04-01

We study the spreading of two mutually cooperative diseases on different network topologies, and with two microscopic realizations, both of which are stochastic versions of a susceptible-infected-removed type model studied by us recently in mean field approximation. There it had been found that cooperativity can lead to first order transitions from spreading to extinction. However, due to the rapid mixing implied by the mean field assumption, first order transitions required nonzero initial densities of sick individuals. For the stochastic model studied here the results depend strongly on the underlying network. First order transitions are found when there are few short but many long loops: (i) No first order transitions exist on trees and on 2-d lattices with local contacts. (ii) They do exist on Erdős-Rényi (ER) networks, on d -dimensional lattices with d ≥4 , and on 2-d lattices with sufficiently long-ranged contacts. (iii) On 3-d lattices with local contacts the results depend on the microscopic details of the implementation. (iv) While single infected seeds can always lead to infinite epidemics on regular lattices, on ER networks one sometimes needs finite initial densities of infected nodes. (v) In all cases the first order transitions are actually "hybrid"; i.e., they display also power law scaling usually associated with second order transitions. On regular lattices, our model can also be interpreted as the growth of an interface due to cooperative attachment of two species of particles. Critically pinned interfaces in this model seem to be in different universality classes than standard critically pinned interfaces in models with forbidden overhangs. Finally, the detailed results mentioned above hold only when both diseases propagate along the same network of links. If they use different links, results can be rather different in detail, but are similar overall.

Control of one- and two-photon absorption in a four-level atomic system by changing the amplitude and phase of a driving microwave field

International Nuclear Information System (INIS)

Hou, B P; Wang, S J; Yu, W L; Sun, W L

2005-01-01

We consider the one- and two-photon absorption spectra of a four-level Y-type atom with the two highest lying levels driven by a microwave field. We found that in the one-photon absorption case, the microwave field can lead to the probe gain, and the absorption and gain spectral structures depend strongly on the microwave field amplitude. For the two-photon absorption case, the strong microwave field can enhance the absorption. When the microwave field amplitude is reduced to a certain value, the single absorption peak in the two-photon spectrum changes into a structure of two-peak structure with different magnitudes. Moreover, the one- and two-photon absorption spectra can be modulated by the phase of the microwave field which produces a closed-loop configuration. Finally, we use the analytic solutions in terms of dressed-state basis to explain the results from our numerical calculation

Coordination of Cooperative Advertising in a Two-Period Fashion and Textiles Supply Chain

Directory of Open Access Journals (Sweden)

Yi He

2014-01-01

Full Text Available Previous studies related to cooperative advertising mainly focus on the one-period supply chain. In the fashion and textiles (FT supply chain, the demand of most FT products (fashion clothing, vogue handbags, fashion shoes, and so on varies over time due to the trends of fashion. In these conditions, a decision-making framework with a multiple-period supply chain becomes more realistic. In view of this, we investigate the optimal cooperative advertising strategies in a two-period FT supply chain consisting of a manufacturer and a retailer in two different scenarios: (i each channel member makes decisions within a cooperative program; (ii the retailer is vertically integrated with a manufacturer. Also, we introduce a two-way subsidy contract to coordinate the supply chain.

Levels-of-growing-stock cooperative study in Douglas-fir: report no. 18--Rocky Brook, 1963-2006.

Science.gov (United States)

Robert O. Curtis; David D. Marshall

2009-01-01

This report documents the history and results of the Rocky Brook installation of the cooperative levels-of-growing-stock (LOGS) study in Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), over the 41-year period 1965 to 2006. This 1938 plantation is one of the two site-IV installations among the nine installations in the study. Much public...

Cooper-pair and Bose-Einstein condensations in two dimensions: A critical analysis based on the Nozieres and Schmitt-Rink formalism

International Nuclear Information System (INIS)

Tokumitu, A.; Miyake, K.; Yamada, K.

1993-01-01

The crossover between the Cooper-pair condensation and the Bose-Einstein condensation of ''di-electronic'' molecules in two-dimensional superconductors is investigated in detail on the basis of the Nozieres and Schmitt-Rink formalism. It is shown that temperature dependence of the chemical potential μ so calculated is classified into two classes as decreasing temperatures; i.e., class (a) where μ approaches the point of Bose-Einstein condensation of two-dimensional ideal Bose gas of ''di-electronic'' molecules, and class (b) where μ diverges positively along the line of BCS-type mean-field pair condensation. This feature is rather universal irrespective of strength V of the attractive interaction of the s-wave type. While the former class (a) has been found by Schmitt-Rink, Varma, and Ruckenstein, existence of the latter class (b) is recognized here. In the case where V is fixed, class (a) is realized for electron number density N smaller than N cr , which is an increasing function of V, and class (b) is realized for N larger than N cr . If N much-gt N cr in particular, there exists a regime, where the Fermi-liquid-like description is valid, between the BCS-type mean-field transition temperature and the Fermi temperature. In the situation where V is changed with N being fixed, low-temperature states for the strong-coupling case belong to class (a) while those for the weak-coupling case belong to class (b). Therefore, with decreasing V, the chemical potential μ(T), at temperatures far below the Fermi temperature, shows a discontinuous jump at V=V cr (N) corresponding to the transition from class (a) to (b)

Uncertainty quantification for mean field games in social interactions

KAUST Repository

Dia, Ben Mansour

2016-01-09

We present an overview of mean field games formulation. A comparative analysis of the optimality for a stochastic McKean-Vlasov process with time-dependent probability is presented. Then we examine mean-field games for social interactions and we show that optimizing the long-term well-being through effort and social feeling state distribution (mean-field) will help to stabilize couple (marriage). However , if the cost of effort is very high, the couple fluctuates in a bad feeling state or the marriage breaks down. We then examine the influence of society on a couple using mean field sentimental games. We show that, in mean-field equilibrium, the optimal effort is always higher than the one-shot optimal effort. Finally we introduce the Wiener chaos expansion for the construction of solution of stochastic differential equations of Mckean-Vlasov type. The method is based on the Cameron-Martin version of the Wiener Chaos expansion and allow to quantify the uncertainty in the optimality system.

Uncertainty quantification for mean field games in social interactions

KAUST Repository

Dia, Ben Mansour

2016-01-01

We present an overview of mean field games formulation. A comparative analysis of the optimality for a stochastic McKean-Vlasov process with time-dependent probability is presented. Then we examine mean-field games for social interactions and we show that optimizing the long-term well-being through effort and social feeling state distribution (mean-field) will help to stabilize couple (marriage). However , if the cost of effort is very high, the couple fluctuates in a bad feeling state or the marriage breaks down. We then examine the influence of society on a couple using mean field sentimental games. We show that, in mean-field equilibrium, the optimal effort is always higher than the one-shot optimal effort. Finally we introduce the Wiener chaos expansion for the construction of solution of stochastic differential equations of Mckean-Vlasov type. The method is based on the Cameron-Martin version of the Wiener Chaos expansion and allow to quantify the uncertainty in the optimality system.

Energy and cooperation among the Scandinavian countries

Energy Technology Data Exchange (ETDEWEB)

Milas, R

1984-11-01

The Scandinavian countries have a long experience of functional cooperation in the field of energy. The oil crisis has been largely attenuated for Norway since the exploitation of the North Sea oil deposits. The future will be oil or nuclear, this is the characteristic of energy cooperation on the Scandinavian, European and international levels. In this connection, no level excludes another and the Scandinavian countries are going to patiently attempt to benefit from their Scandinavian dimension over the short range, their European vocation for research and development and their free trade ideology for the surveillance of markets on the level of international agencies.

Many-Body Mean-Field Equations: Parallel implementation

International Nuclear Information System (INIS)

Vallieres, M.; Umar, S.; Chinn, C.; Strayer, M.

1993-01-01

We describe the implementation of Hartree-Fock Many-Body Mean-Field Equations on a Parallel Intel iPSC/860 hypercube. We first discuss the Nuclear Mean-Field approach in physical terms. Then we describe our parallel implementation of this approach on the Intel iPSC/860 hypercube. We discuss and compare the advantages and disadvantages of the domain partition versus the Hilbert space partition for this problem. We conclude by discussing some timing experiments on various computing platforms

Classification of integrable two-dimensional models of relativistic field theory by means of computer

International Nuclear Information System (INIS)

Getmanov, B.S.

1988-01-01

The results of classification of two-dimensional relativistic field models (1) spinor; (2) essentially-nonlinear scalar) possessing higher conservation laws using the system of symbolic computer calculations are presented shortly

Energy-efficient power allocation of two-hop cooperative systems with imperfect channel estimation

KAUST Repository

Amin, Osama; Bedeer, Ebrahim; Ahmed, Mohamed H.; Dobre, Octavia A.; Alouini, Mohamed-Slim

2015-01-01

an accurate EE metric for cooperative two-hop systems that use the amplify-and-forward relaying scheme. Different from the existing research that assumes the availability of perfect channel state information (CSI) at the communication cooperative nodes, we

A Fractional Micro-Macro Model for Crowds of Pedestrians Based on Fractional Mean Field Games

Institute of Scientific and Technical Information of China (English)

Kecai Cao; Yang Quan Chen; Daniel Stuart

2016-01-01

Modeling a crowd of pedestrians has been considered in this paper from different aspects. Based on fractional microscopic model that may be much more close to reality, a fractional macroscopic model has been proposed using conservation law of mass. Then in order to characterize the competitive and cooperative interactions among pedestrians, fractional mean field games are utilized in the modeling problem when the number of pedestrians goes to infinity and fractional dynamic model composed of fractional backward and fractional forward equations are constructed in macro scale. Fractional micromacro model for crowds of pedestrians are obtained in the end.Simulation results are also included to illustrate the proposed fractional microscopic model and fractional macroscopic model,respectively.

Entropy squeezing for a two-level atom in two-mode Raman coupled model with intrinsic decoherence

Institute of Scientific and Technical Information of China (English)

Zhang Jian; Shao Bin; Zou Jian

2009-01-01

In this paper,we investigate the entropy squeezing for a two-level atom interacting with two quantized fields through Raman coupling.We obtain the dynamical evolution of the total system under the influence of intrinsic decoherence when the two quantized fields are prepared in a two-mode squeezing vacuum state initially.The effects of the field squeezing factor,the two-level atomic transition frequency,the second field frequency and the intrinsic decoherence on the entropy squeezing are discussed.Without intrinsic decoherence,the increase of field squeezing factor can break the entropy squeezing.The two-level atomic transition frequency changes only the period of oscillation but not the strength of entropy squeezing.The influence of the second field frequency is complicated.With the intrinsic decoherence taken into consideration,the results show that the stronger the intrinsic decoherence is,the more quickly the entropy squeezing will disappear.The increase of the atomic transition frequency can hasten the disappearance of entropy squeezing.

Entropy squeezing for a two-level atom in two-mode Raman coupled model with intrinsic decoherence

International Nuclear Information System (INIS)

Jian, Zhang; Bin, Shao; Jian, Zou

2009-01-01

In this paper, we investigate the entropy squeezing for a two-level atom interacting with two quantized fields through Raman coupling. We obtain the dynamical evolution of the total system under the influence of intrinsic decoherence when the two quantized fields are prepared in a two-mode squeezing vacuum state initially. The effects of the field squeezing factor, the two-level atomic transition frequency, the second field frequency and the intrinsic decoherence on the entropy squeezing are discussed. Without intrinsic decoherence, the increase of field squeezing factor can break the entropy squeezing. The two-level atomic transition frequency changes only the period of oscillation but not the strength of entropy squeezing. The influence of the second field frequency is complicated. With the intrinsic decoherence taken into consideration, the results show that the stronger the intrinsic decoherence is, the more quickly the entropy squeezing will disappear. The increase of the atomic transition frequency can hasten the disappearance of entropy squeezing. (classical areas of phenomenology)

Linear–Quadratic Mean-Field-Type Games: A Direct Method

Directory of Open Access Journals (Sweden)

Tyrone E. Duncan

2018-02-01

Full Text Available In this work, a multi-person mean-field-type game is formulated and solved that is described by a linear jump-diffusion system of mean-field type and a quadratic cost functional involving the second moments, the square of the expected value of the state, and the control actions of all decision-makers. We propose a direct method to solve the game, team, and bargaining problems. This solution approach does not require solving the Bellman–Kolmogorov equations or backward–forward stochastic differential equations of Pontryagin’s type. The proposed method can be easily implemented by beginners and engineers who are new to the emerging field of mean-field-type game theory. The optimal strategies for decision-makers are shown to be in a state-and-mean-field feedback form. The optimal strategies are given explicitly as a sum of the well-known linear state-feedback strategy for the associated deterministic linear–quadratic game problem and a mean-field feedback term. The equilibrium cost of the decision-makers are explicitly derived using a simple direct method. Moreover, the equilibrium cost is a weighted sum of the initial variance and an integral of a weighted variance of the diffusion and the jump process. Finally, the method is used to compute global optimum strategies as well as saddle point strategies and Nash bargaining solution in state-and-mean-field feedback form.

Cooperative field test program for wind systems. Final report

Energy Technology Data Exchange (ETDEWEB)

Bollmeier, W.S. II; Dodge, D.M.

1992-03-01

The objectives of the Federal Wind Energy Program, managed by the US Department of Energy (DOE), are (1) to assist industry and utilities in achieving a multi-regional US market penetration of wind systems, and (2) to establish the United States as the world leader in the development of advanced wind turbine technology. In 1984, the program conducted a series of planning workshops with representatives from the wind energy industry to obtain input on the Five-Year Research Plan then being prepared by DOE. One specific suggestion that came out of these meetings was that the federal program should conduct cooperative research tests with industry to enhance the technology transfer process. It was also felt that the active involvement of industry in DOE-funded research would improve the state of the art of wind turbine technology. DOE established the Cooperative Field Test Program (CFTP) in response to that suggestion. This program was one of the first in DOE to feature joint industry-government research test teams working toward common objectives.

The experimental setup of a large field operational test for cooperative driving vehicles at the A270

NARCIS (Netherlands)

Broek, T.H.A. van den; Netten, B.D.; Hoedemaeker, M.; Ploeg, J.

2010-01-01

In this paper, a large field operational test (FOT) for cooperative driving systems, which take place on a public highway, is discussed. The experimental setup consist of a specific driver support system, which is closely related to cooperative adaptive cruise control (CACC) systems. Instead of

Implementation of Cooperation for Recycling Vehicle Routing Optimization in Two-Echelon Reverse Logistics Networks

Directory of Open Access Journals (Sweden)

Yong Wang

2018-04-01

Full Text Available The formation of a cooperative alliance is an effective means of approaching the vehicle routing optimization in two-echelon reverse logistics networks. Cooperative mechanisms can contribute to avoiding the inefficient assignment of resources for the recycling logistics operations and reducing long distance transportation. With regard to the relatively low performance of waste collection, this paper proposes a three-phase methodology to properly address the corresponding vehicle routing problem on two echelons. First, a bi-objective programming model is established to minimize the total cost and the number of vehicles considering semitrailers and vehicles sharing. Furthermore, the Clarke–Wright (CW savings method and the Non-dominated Sorting Genetic Algorithm-II (NSGA-II are combined to design a hybrid routing optimization heuristic, which is denoted CW_NSGA-II. Routes on the first and second echelons are obtained on the basis of sub-optimal solutions provided by CW algorithm. Compared to other intelligent algorithms, CW_NSGA-II reduces the complexity of the multi-objective solutions search and mostly converges to optimality. The profit generated by cooperation among retail stores and the recycling hub in the reverse logistics network is fairly and reasonably distributed to the participants by applying the Minimum Costs-Remaining Savings (MCRS method. Finally, an empirical study in Chengdu City, China, reveals the superiority of CW_NSGA over the multi-objective particle swarm optimization and the multi objective genetic algorithms in terms of solutions quality and convergence. Meanwhile, the comparison of MCRS method with the Shapley value model, equal profit method and cost gap allocation proves that MCRS method is more conducive to the stability of the cooperative alliance. In general, the implementation of cooperation in the optimization of the reverse logistics network effectively leads to the sustainable development of urban and sub

Gender, trust and cooperation in environmental social dilemmas.

Science.gov (United States)

Irwin, Kyle; Edwards, Kimberly; Tamburello, Jeffrey A

2015-03-01

This research addresses gender differences in environmental protection efforts. Recent work indicates that, across a variety of domains, women are more generous, charitable, and prosocial than men. Despite above-average levels of these motivators for cooperation, considerable experimental research points to no difference in cooperation between genders. What can explain women's lower-than-expected cooperation levels? Prior research indicates that, compared to men, women are less trusting and respond to fear incentives in social dilemmas - they are concerned about being exploited. We test these arguments in the context of environmental behaviors and argue that lower trust and greater responses to fear incentives mean that women's cooperation is predicated on trust. For men, trust does not predict environmental cooperation. The current research represents the first empirical test of these arguments. Using data from the General Social Survey we focus on private sphere behaviors and political participation and predict an interaction between gender and trust on cooperation. Results support this prediction. Copyright © 2014 Elsevier Inc. All rights reserved.

Individual choice and reputation distribution of cooperative behaviors among heterogeneous groups

International Nuclear Information System (INIS)

Lu, Peng

2015-01-01

Highlights: •Cooperation macrocosmically refers to the overall cooperation rate, while reputation microcosmically records individual choices. •Therefore, reputation should be preferred in order to investigate how individual choices evolve. •Both the mean and standard deviation of reputation follow clear patterns, and some factors have quadratic effects on them. -- Abstract: Cooperation is vital for our society, but the temptation of cheating on cooperative partners undermines cooperation. The mechanism of reputation is raised to countervail this temptation and therefore promote cooperation. Reputation microcosmically records individual choices, while cooperation macrocosmically refers to the group or averaged cooperation level. Reputation should be preferred in order to investigate how individual choices evolve. In this work, we study the distribution of reputation to figure out how individuals make choices within cooperation and defection. We decompose reputation into its mean and standard deviation and inspect effects of their factors respectively. To achieve this goal, we construct a model where agents of three groups or classes play the prisoners’ dilemma game with neighbors on a square lattice. It indicates in outcomes that the distribution of reputation is distinct from that of cooperation and both the mean and standard deviation of reputation follow clear patterns. Some factors have negative quadratic effects on reputation's mean or standard deviation, and some have merely linear effects

Two-agent cooperative search using game models with endurance-time constraints

Science.gov (United States)

Sujit, P. B.; Ghose, Debasish

2010-07-01

In this article, the problem of two Unmanned Aerial Vehicles (UAVs) cooperatively searching an unknown region is addressed. The search region is discretized into hexagonal cells and each cell is assumed to possess an uncertainty value. The UAVs have to cooperatively search these cells taking limited endurance, sensor and communication range constraints into account. Due to limited endurance, the UAVs need to return to the base station for refuelling and also need to select a base station when multiple base stations are present. This article proposes a route planning algorithm that takes endurance time constraints into account and uses game theoretical strategies to reduce the uncertainty. The route planning algorithm selects only those cells that ensure the agent will return to any one of the available bases. A set of paths are formed using these cells which the game theoretical strategies use to select a path that yields maximum uncertainty reduction. We explore non-cooperative Nash, cooperative and security strategies from game theory to enhance the search effectiveness. Monte-Carlo simulations are carried out which show the superiority of the game theoretical strategies over greedy strategy for different look ahead step length paths. Within the game theoretical strategies, non-cooperative Nash and cooperative strategy perform similarly in an ideal case, but Nash strategy performs better than the cooperative strategy when the perceived information is different. We also propose a heuristic based on partitioning of the search space into sectors to reduce computational overhead without performance degradation.

Mean-field approximations of fixation time distributions of evolutionary game dynamics on graphs

Science.gov (United States)

Ying, Li-Min; Zhou, Jie; Tang, Ming; Guan, Shu-Guang; Zou, Yong

2018-02-01

The mean fixation time is often not accurate for describing the timescales of fixation probabilities of evolutionary games taking place on complex networks. We simulate the game dynamics on top of complex network topologies and approximate the fixation time distributions using a mean-field approach. We assume that there are two absorbing states. Numerically, we show that the mean fixation time is sufficient in characterizing the evolutionary timescales when network structures are close to the well-mixing condition. In contrast, the mean fixation time shows large inaccuracies when networks become sparse. The approximation accuracy is determined by the network structure, and hence by the suitability of the mean-field approach. The numerical results show good agreement with the theoretical predictions.

Entanglement Dynamics of Linear and Nonlinear Interaction of Two Two-Level Atoms with a Quantized Phase-Damped Field in the Dispersive Regime

Science.gov (United States)

Tavassoly, M. K.; Daneshmand, R.; Rustaee, N.

2018-06-01

In this paper we study the linear and nonlinear (intensity-dependent) interactions of two two-level atoms with a single-mode quantized field far from resonance, while the phase-damping effect is also taken into account. To find the analytical solution of the atom-field state vector corresponding to the considered model, after deducing the effective Hamiltonian we evaluate the time-dependent elements of the density operator using the master equation approach and superoperator method. Consequently, we are able to study the influences of the special nonlinearity function f (n) = √ {n}, the intensity of the initial coherent state field and the phase-damping parameter on the degree of entanglement of the whole system as well as the field and atom. It is shown that in the presence of damping, by passing time, the amount of entanglement of each subsystem with the rest of system, asymptotically reaches to its stationary and maximum value. Also, the nonlinear interaction does not have any effect on the entanglement of one of the atoms with the rest of system, but it changes the amplitude and time period of entanglement oscillations of the field and the other atom. Moreover, this may cause that, the degree of entanglement which may be low (high) at some moments of time becomes high (low) by entering the intensity-dependent function in the atom-field coupling.

Joint Preprocesser-Based Detectors for One-Way and Two-Way Cooperative Communication Networks

KAUST Repository

Abuzaid, Abdulrahman I.

2014-05-01

Efficient receiver designs for cooperative communication networks are becoming increasingly important. In previous work, cooperative networks communicated with the use of L relays. As the receiver is constrained, channel shortening and reduced-rank techniques were employed to design the preprocessing matrix that reduces the length of the received vector from L to U. In the first part of the work, a receiver structure is proposed which combines our proposed threshold selection criteria with the joint iterative optimization (JIO) algorithm that is based on the mean square error (MSE). Our receiver assists in determining the optimal U. Furthermore, this receiver provides the freedom to choose U for each frame depending on the tolerable difference allowed for MSE. Our study and simulation results show that by choosing an appropriate threshold, it is possible to gain in terms of complexity savings while having no or minimal effect on the BER performance of the system. Furthermore, the effect of channel estimation on the performance of the cooperative system is investigated. In the second part of the work, a joint preprocessor-based detector for cooperative communication networks is proposed for one-way and two-way relaying. This joint preprocessor-based detector operates on the principles of minimizing the symbol error rate (SER) instead of minimizing MSE. For a realistic assessment, pilot symbols are used to estimate the channel. From our simulations, it can be observed that our proposed detector achieves the same SER performance as that of the maximum likelihood (ML) detector with all participating relays. Additionally, our detector outperforms selection combining (SC), channel shortening (CS) scheme and reduced-rank techniques when using the same U. Finally, our proposed scheme has the lowest computational complexity.

Closing the Gap Between Research and Field Applications for Multi-UAV Cooperative Missions

Science.gov (United States)

2013-09-01

REPORT DATE September 2013 3. REPORT TYPE AND DATES COVERED Master’s Thesis 4. TITLE AND SUBTITLE CLOSING THE GAP BETWEEN RESEARCH AND FIELD...iii Approved for public release; distribution is unlimited CLOSING THE GAP BETWEEN RESEARCH AND FIELD APPLICATIONS FOR MULTI-UAV COOPERATIVE...the report is to lay the groundwork for future analysis in multi-UAV analysis to close the gap between existing research and efficient multi-UAV

International cooperation in the peaceful use of nuclear energy

International Nuclear Information System (INIS)

Jacke, S.; Stein, G.

1988-01-01

The article in hand reviews the scenario and organisation of the conference together with the results achieved (non-proliferation strategies with regard to technological cooperation in the nuclear field, feasible means of cooperation), saying that judged by the non-favourable conditions at the start, the fruitful dialogue between developing countries and highly industrialised countries that has set in at this conference will have to be filed on the credit side. Another important result is that one came to realize that the transfer of know-how must be very carefully prepared and accompanied by very close cooperation right from the start. (orig./DG) [de

Bargmann representation for Landau levels in two dimensions

Energy Technology Data Exchange (ETDEWEB)

Rohringer, Nina [Institute for Theoretical Physics, Vienna University of Technology, Wiedner Hauptstr. 8-10, A-1040 Vienna (Austria); Burgdoerfer, Joachim [Institute for Theoretical Physics, Vienna University of Technology, Wiedner Hauptstr. 8-10, A-1040 Vienna (Austria); Macris, Nicolas [Institut de Physique Theorique, Ecole Polytechnique Federale de Lausanne, CH-1015 Lausanne (Switzerland)

2003-04-11

We present a formulation of the quantum mechanics of an electron gas confined to two dimensions in a strong magnetic field within the framework of the Hilbert space of analytic functions (Bargmann's space). Our approach extends the representation introduced by Girvin and Jach for the ground state to arbitrary Landau levels and to the regime of coupling between Landau levels. By projecting out the rapid cyclotron motion, the quantum mechanics of the slow guiding centre motion is converted into a system of coupled-channel equations describing the coupling between Landau levels due to the (disorder) potentials. In the limit of strong fields, the coupled-channel equations can be solved perturbatively. For the single-channel case we derive a WKB-like quantization condition for the one-dimensional motion along equipotential lines for arbitrary Landau levels. Two applications of this formalism are discussed: the weak-levitation problem in quantum Hall systems and a two-electron quantum dot in a strong magnetic field.

Bargmann representation for Landau levels in two dimensions

International Nuclear Information System (INIS)

Rohringer, Nina; Burgdoerfer, Joachim; Macris, Nicolas

2003-01-01

We present a formulation of the quantum mechanics of an electron gas confined to two dimensions in a strong magnetic field within the framework of the Hilbert space of analytic functions (Bargmann's space). Our approach extends the representation introduced by Girvin and Jach for the ground state to arbitrary Landau levels and to the regime of coupling between Landau levels. By projecting out the rapid cyclotron motion, the quantum mechanics of the slow guiding centre motion is converted into a system of coupled-channel equations describing the coupling between Landau levels due to the (disorder) potentials. In the limit of strong fields, the coupled-channel equations can be solved perturbatively. For the single-channel case we derive a WKB-like quantization condition for the one-dimensional motion along equipotential lines for arbitrary Landau levels. Two applications of this formalism are discussed: the weak-levitation problem in quantum Hall systems and a two-electron quantum dot in a strong magnetic field

Bargmann representation for Landau levels in two dimensions

CERN Document Server

Rohringer, N; Macris, N

2003-01-01

We present a formulation of the quantum mechanics of an electron gas confined to two dimensions in a strong magnetic field within the framework of the Hilbert space of analytic functions (Bargmann's space). Our approach extends the representation introduced by Girvin and Jach for the ground state to arbitrary Landau levels and to the regime of coupling between Landau levels. By projecting out the rapid cyclotron motion, the quantum mechanics of the slow guiding centre motion is converted into a system of coupled-channel equations describing the coupling between Landau levels due to the (disorder) potentials. In the limit of strong fields, the coupled-channel equations can be solved perturbatively. For the single-channel case we derive a WKB-like quantization condition for the one-dimensional motion along equipotential lines for arbitrary Landau levels. Two applications of this formalism are discussed: the weak-levitation problem in quantum Hall systems and a two-electron quantum dot in a strong magnetic field...

Evolution, epigenetics and cooperation.

Science.gov (United States)

Bateson, Patrick

2014-04-01

Explanations for biological evolution in terms of changes in gene frequencies refer to outcomes rather than process. Integrating epigenetic studies with older evolutionary theories has drawn attention to the ways in which evolution occurs. Adaptation at the level of the gene is givingway to adaptation at the level of the organism and higher-order assemblages of organisms. These ideas impact on the theories of how cooperation might have evolved. Two of the theories, i.e. that cooperating individuals are genetically related or that they cooperate for self-interested reasons, have been accepted for a long time. The idea that adaptation takes place at the level of groups is much more controversial. However, bringing together studies of development with those of evolution is taking away much of the heat in the debate about the evolution of group behaviour.

Toward Transdisciplinary Research by Means of Cooperative Learning

Directory of Open Access Journals (Sweden)

José Aureliano Betancourt Bethencourt

2014-01-01

Full Text Available This paper is based on the observation that fifth year Medicine students do not have enough skills in statistics, IT, or information management to adequately prepare and implement research projects. Therefore, the aim of this paper is to describe the experiences obtained by using the cooperative learning method and to present the results obtained by students in their research projects.  In order to meet the proposed objectives the cooperative learning method was applied to several topics of the Public Health course in the Medical Program.  Consequently, students were divided into five groups to interact with health care specialists and workers, workers from other sectors, and the general public. They identified the most urgent health problems in a participative manner and conducted a research project. The students’ acceptance of the method was evaluated using an exploratory statistical technique.  As a result, students analyzed data, drew conclusions, and participated in debates having the professor as the facilitator and coordinator. All groups successfully presented the results of their research projects, which included 2 projects on the control of Dengue and the Aedes aegypti mosquito and 3 on potential maternal mortality risks. Surveys reflected acceptance of the method.  The experiences obtained by using the cooperative learning technique and the results obtained by students in their projects are described; this experience should be systematized.

Electronic structure and core-level spectra of light actinide dioxides in the dynamical mean-field theory

Czech Academy of Sciences Publication Activity Database

Kolorenč, Jindřich; Shick, Alexander; Lichtenstein, A.I.

2015-01-01

Roč. 92, č. 8 (2015), "085125-1"-"085125-10" ISSN 1098-0121 R&D Projects: GA ČR GC15-05872J Institutional support: RVO:68378271 Keywords : electronic-structure calculations * dynamical mean-field theory * Mott insulators * actinides * oxides * photoemission Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.736, year: 2014

Microbunching instability in a chicane: Two-dimensional mean field treatment

Directory of Open Access Journals (Sweden)

Gabriele Bassi

2009-08-01

Full Text Available We study the microbunching instability in a bunch compressor by a parallel code with some improved numerical algorithms. The two-dimensional charge/current distribution is represented by a Fourier series, with coefficients determined through Monte Carlo sampling over an ensemble of tracked points. This gives a globally smooth distribution with low noise. The field equations are solved accurately in the lab frame using retarded potentials and a novel choice of integration variables that eliminates singularities. We apply the scheme with parameters for the first bunch compressor system of FERMI@Elettra, with emphasis on the amplification of a perturbation at a particular wavelength and the associated longitudinal bunch spectrum. Gain curves are in rough agreement with those of the linearized Vlasov system at intermediate wavelengths, but show some deviation at the smallest wavelengths treated and show the breakdown of a coasting beam assumption at long wavelengths. The linearized Vlasov system is discussed in some detail. A new 2D integral equation is derived which reduces to a well-known 1D integral equation in the coasting beam case.

Comparison of two different running models for the shock wave lithotripsy machine in Taipei City Hospital: self-support versus outsourcing cooperation.

Science.gov (United States)

Huang, Chi-Yi; Chen, Shiou-Sheng; Chen, Li-Kuei

2009-10-01

To compare two different running models including self-support and outsourcing cooperation for the extracorporeal shock wave lithotripsy (SWL) machine in Taipei City Hospital, we made a retrospective study. Self-support means that the hospital has to buy an SWL machine and get all the payment from SWL. In outsourcing cooperation, the cooperative company provides an SWL machine and shares the payment with the hospital. Between January 2002 and December 2006, we used self-support for the SWL machine, and from January 2007 to December 2008, we used outsourcing cooperation. We used the method of full costing to calculate the cost of SWL, and the break-even point was the lowest number of treatment sessions of SWL to make balance of payments every month. Quality parameters including stone-free rate, retreatment rate, additional procedures and complication rate were evaluated. When outsourcing cooperation was used, there were significantly more treatment sessions of SWL every month than when utilizing self-support (36.3 +/- 5.1 vs. 48.1 +/- 8.4, P = 0.03). The cost of SWL for every treatment session was significantly higher using self-support than with outsourcing cooperation (25027.5 +/- 1789.8 NT$ vs. 21367.4 +/- 201.0 NT$). The break-even point was 28.3 (treatment sessions) for self-support, and 28.4 for outsourcing cooperation, when the hospital got 40% of the payment, which would decrease if the percentage increased. No significant differences were noticed for stone-free rate, retreatment rate, additional procedures and complication rate of SWL between the two running models. Besides, outsourcing cooperation had lower cost (every treatment session), but a greater number of treatment sessions of SWL every month than self-support.

Mean field approach to nuclear structure

International Nuclear Information System (INIS)

Nazarewicz, W.; Tennessee Univ., Knoxville, TN

1993-01-01

Several examples of mean-field calculations, relevant to the recent and planned low-spin experimental works, are presented. The perspectives for future studies (mainly related to spectroscopy of exotic nuclei) are reviewd

Self-consistent mean-field models for nuclear structure

International Nuclear Information System (INIS)

Bender, Michael; Heenen, Paul-Henri; Reinhard, Paul-Gerhard

2003-01-01

The authors review the present status of self-consistent mean-field (SCMF) models for describing nuclear structure and low-energy dynamics. These models are presented as effective energy-density functionals. The three most widely used variants of SCMF's based on a Skyrme energy functional, a Gogny force, and a relativistic mean-field Lagrangian are considered side by side. The crucial role of the treatment of pairing correlations is pointed out in each case. The authors discuss other related nuclear structure models and present several extensions beyond the mean-field model which are currently used. Phenomenological adjustment of the model parameters is discussed in detail. The performance quality of the SCMF model is demonstrated for a broad range of typical applications

Joint declaration on co-operation in the field of the peaceful use of nuclear energy between France and the Federal Republic of Germany

International Nuclear Information System (INIS)

1989-06-01

This Declaration follows upon the signing of a Protocol of intent on 3 April 1989 by VEBA, the major energy consortium in the Federal Republic of Germany supplying nuclear power, and COGEMA, the French State-owned nuclear fuel company and aims to provide a broad framework for co-operation between the two countries. The Declaration, in particular, covers co-operation in the fields of reprocessing, production of MOX fuel (mixed oxide fuel), uranium enrichment, nuclear reactors, information relating to nuclear installations, transport of nuclear material [fr

Cooperative OFDM underwater acoustic communications

CERN Document Server

Cheng, Xilin; Cheng, Xiang

2016-01-01

Following underwater acoustic channel modeling, this book investigates the relationship between coherence time and transmission distances. It considers the power allocation issues of two typical transmission scenarios, namely short-range transmission and medium-long range transmission. For the former scenario, an adaptive system is developed based on instantaneous channel state information. The primary focus is on cooperative dual-hop orthogonal frequency division multiplexing (OFDM). This book includes the decomposed fountain codes designed to enable reliable communications with higher energy efficiency. It covers the Doppler Effect, which improves packet transmission reliability for effective low-complexity mirror-mapping-based intercarrier interference cancellation schemes capable of suppressing the intercarrier interference power level. Designed for professionals and researchers in the field of underwater acoustic communications, this book is also suitable for advanced-level students in electrical enginee...

Generalized quantum mean-field systems and their application to ultracold atoms

International Nuclear Information System (INIS)

Trimborn-Witthaut, Friederike Annemarie

2011-01-01

Strongly interacting many-body systems consisting of a large number of indistinguishable particles play an important role in many areas of physics. Though such systems are hard to deal with theoretically since the dimension of the respective Hilbert space increases exponentially both in the particle number and in the number of system modes. Therefore, approximations are of considerable interest. The mean-field approximation describes the behaviour in the macroscopic limit N→∞, which leads to an effective nonlinear single-particle problem. Although this approximation is widely used, rigorous results on the applicability and especially on finite size corrections are extremely rare. One prominent example of strongly interacting many-body systems are ultracold atoms in optical lattices, which are a major subject of this thesis. Typically these systems consist of a large but well-defined number of particles, such that corrections to the mean-field limit can be systematically studied. This thesis is divided into two parts: In the first part we study generalized quantum mean-field systems in a C * -algebraic framework. These systems are characterized by their intrinsic permutation symmetry. In the limit of infinite system size, N→∞, the intensive observables converge to the commutative algebra of weak * -continuous functions on the single particle state space. To quantify the deviations from the meanfield prediction for large but finite N, we establish a differential calculus for state space functions and provide a generalized Taylor expansion around the mean-field limit. Furthermore, we introduce the algebra of macroscopic fluctuations around the mean-field limit and prove a quantum version of the central limit theorem. On the basis of these results, we give a detailed study of the finite size corrections to the ground state energy and establish bounds, for both the quantum and the classical case. Finally, we restrict ourselves to the subspace of Bose

Symplectic manifolds, coadjoint orbits, and Mean Field Theory

International Nuclear Information System (INIS)

Rosensteel, G.

1986-01-01

Mean field theory is given a geometrical interpretation as a Hamiltonian dynamical system. The Hartree-Fock phase space is the Grassmann manifold, a symplectic submanifold of the projective space of the full many-fermion Hilbert space. The integral curves of the Hartree-Fock vector field are the time-dependent Hartree-Fock solutions, while the critical points of the energy function are the time-independent states. The mean field theory is generalized beyond determinants to coadjoint orbit spaces of the unitary group; the Grassmann variety is the minimal coadjoint orbit

The nuclear N-body problem and the effective interaction in self-consistent mean-field methods

International Nuclear Information System (INIS)

Duguet, Thomas

2002-01-01

This work deals with two aspects of mean-field type methods extensively used in low-energy nuclear structure. The first study is at the mean-field level. The link between the wave-function describing an even-even nucleus and the odd-even neighbor is revisited. To get a coherent description as a function of the pairing intensity in the system, the utility of the formalization of this link through a two steps process is demonstrated. This two-steps process allows to identify the role played by different channels of the force when a nucleon is added in the system. In particular, perturbative formula evaluating the contribution of time-odd components of the functional to the nucleon separation energy are derived for zero and realistic pairing intensities. Self-consistent calculations validate the developed scheme as well as the derived perturbative formula. This first study ends up with an extended analysis of the odd-even mass staggering in nuclei. The new scheme allows to identify the contribution to this observable coming from different channels of the force. The necessity of a better understanding of time-odd terms in order to decide which odd-even mass formulae extracts the pairing gap the most properly is identified. These terms being nowadays more or less out of control, extended studies are needed to make precise the fit of a pairing force through the comparison of theoretical and experimental odd-even mass differences. The second study deals with beyond mean-field methods taking care of the correlations associated with large amplitude oscillations in nuclei. Their effects are usually incorporated through the GCM or the projected mean-field method. We derive a perturbation theory motivating such variational calculations from a diagrammatic point of view for the first time. Resuming two-body correlations in the energy expansion, we obtain an effective interaction removing the hard-core problem in the context of configuration mixing calculations. Proceeding to a

Designing for cooperation - cooperating in design

DEFF Research Database (Denmark)

Kyng, Morten

1991-01-01

This article will discuss how to design computer applications that enhance the quality of work and products, and will relate the discussion to current themes in the field of Computer-Supported Cooperative Work (CSCW). Cooperation is a key element of computer use and work practice, yet here...... a specific "CSCW approach is not taken." Instead the focus is cooperation as an important aspect of work that should be integrated into most computer support efforts in order to develop successful computer support, however, other aspects such as power, conflict and control must also be considered....

Double giant resonances in time-dependent relativistic mean-field theory

International Nuclear Information System (INIS)

Ring, P.; Podobnik, B.

1996-01-01

Collective vibrations in spherical nuclei are described in the framework of time-dependent relativistic mean-field theory (RMFT). Isoscalar quadrupole and isovector dipole oscillations that correspond to giant resonances are studied, and possible excitations of higher modes are investigated. We find evidence for modes which can be interpreted as double resonances. In a quantized RMFT they correspond to two-phonon states. (orig.)

How feeling betrayed affects cooperation.

Science.gov (United States)

Ramazi, Pouria; Hessel, Jop; Cao, Ming

2015-01-01

For a population of interacting self-interested agents, we study how the average cooperation level is affected by some individuals' feelings of being betrayed and guilt. We quantify these feelings as adjusted payoffs in asymmetric games, where for different emotions, the payoff matrix takes the structure of that of either a prisoner's dilemma or a snowdrift game. Then we analyze the evolution of cooperation in a well-mixed population of agents, each of whom is associated with such a payoff matrix. At each time-step, an agent is randomly chosen from the population to update her strategy based on the myopic best-response update rule. According to the simulations, decreasing the feeling of being betrayed in a portion of agents does not necessarily increase the level of cooperation in the population. However, this resistance of the population against low-betrayal-level agents is effective only up to some extend that is explicitly determined by the payoff matrices and the number of agents associated with these matrices. Two other models are also considered where the betrayal factor of an agent fluctuates as a function of the number of cooperators and defectors that she encounters. Unstable behaviors are observed for the level of cooperation in these cases; however, we show that one can tune the parameters in the function to make the whole population become cooperative or defective.

How feeling betrayed affects cooperation.

Directory of Open Access Journals (Sweden)

Pouria Ramazi

Full Text Available For a population of interacting self-interested agents, we study how the average cooperation level is affected by some individuals' feelings of being betrayed and guilt. We quantify these feelings as adjusted payoffs in asymmetric games, where for different emotions, the payoff matrix takes the structure of that of either a prisoner's dilemma or a snowdrift game. Then we analyze the evolution of cooperation in a well-mixed population of agents, each of whom is associated with such a payoff matrix. At each time-step, an agent is randomly chosen from the population to update her strategy based on the myopic best-response update rule. According to the simulations, decreasing the feeling of being betrayed in a portion of agents does not necessarily increase the level of cooperation in the population. However, this resistance of the population against low-betrayal-level agents is effective only up to some extend that is explicitly determined by the payoff matrices and the number of agents associated with these matrices. Two other models are also considered where the betrayal factor of an agent fluctuates as a function of the number of cooperators and defectors that she encounters. Unstable behaviors are observed for the level of cooperation in these cases; however, we show that one can tune the parameters in the function to make the whole population become cooperative or defective.

Coagulation kinetics beyond mean field theory using an optimised Poisson representation

Energy Technology Data Exchange (ETDEWEB)

Burnett, James [Department of Mathematics, UCL, Gower Street, London WC1E 6BT (United Kingdom); Ford, Ian J. [Department of Physics and Astronomy, UCL, Gower Street, London WC1E 6BT (United Kingdom)

2015-05-21

Binary particle coagulation can be modelled as the repeated random process of the combination of two particles to form a third. The kinetics may be represented by population rate equations based on a mean field assumption, according to which the rate of aggregation is taken to be proportional to the product of the mean populations of the two participants, but this can be a poor approximation when the mean populations are small. However, using the Poisson representation, it is possible to derive a set of rate equations that go beyond mean field theory, describing pseudo-populations that are continuous, noisy, and complex, but where averaging over the noise and initial conditions gives the mean of the physical population. Such an approach is explored for the simple case of a size-independent rate of coagulation between particles. Analytical results are compared with numerical computations and with results derived by other means. In the numerical work, we encounter instabilities that can be eliminated using a suitable “gauge” transformation of the problem [P. D. Drummond, Eur. Phys. J. B 38, 617 (2004)] which we show to be equivalent to the application of the Cameron-Martin-Girsanov formula describing a shift in a probability measure. The cost of such a procedure is to introduce additional statistical noise into the numerical results, but we identify an optimised gauge transformation where this difficulty is minimal for the main properties of interest. For more complicated systems, such an approach is likely to be computationally cheaper than Monte Carlo simulation.

Antiferromagnetic and topological states in silicene: A mean field study

Science.gov (United States)

Liu, Feng; Liu, Cheng-Cheng; Yao, Yu-Gui

2015-08-01

It has been widely accepted that silicene is a topological insulator, and its gap closes first and then opens again with increasing electric field, which indicates a topological phase transition from the quantum spin Hall state to the band insulator state. However, due to the relatively large atomic spacing of silicene, which reduces the bandwidth, the electron-electron interaction in this system is considerably strong and cannot be ignored. The Hubbard interaction, intrinsic spin orbital coupling (SOC), and electric field are taken into consideration in our tight-binding model, with which the phase diagram of silicene is carefully investigated on the mean field level. We have found that when the magnitudes of the two mass terms produced by the Hubbard interaction and electric potential are close to each other, the intrinsic SOC flips the sign of the mass term at either K or K‧ for one spin and leads to the emergence of the spin-polarized quantum anomalous Hall state. Project supported by the National Key Basic Research Program of China (Grant Nos. 2014CB920903, 2013CB921903, 2011CBA00108, and 2012CB937500), the National Natural Science Foundation of China (Grant Nos. 11021262, 11172303, 11404022, 11225418, and 11174337), the Specialized Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20121101110046), the Excellent Young Scholars Research Fund of Beijing Institute of Technology (Grant No. 2014CX04028), and the Basic Research Funds of Beijing Institute of Technology (Grant No. 20141842001).

Co-operation and Self-Organization

Directory of Open Access Journals (Sweden)

Christian Fuchs

2008-07-01

Full Text Available Co-operation has its specific meanings in physical (dissipative, biological (autopoietic and social (re-creative systems. On upper hierarchical systemic levels there are additional, emergent properties of co-operation, co-operation evolves dialectically. The focus of this paper is human cooperation. Social systems permanently reproduce themselves in a loop that mutually connects social structures and actors. Social structures enable and constrain actions, they are medium and outcome of social actions. This reflexive process is termed re-creation and describes the process of social selforganization. Co-operation in a very weak sense means coaction and takes place permanently in re-creative systems: two or more actors act together in a co-ordinated manner so that a new emergent property emerges. Co-action involves the formation of forces, environment and sense (dispositions, decisions, definitions. Mechanistic approaches conceive coaction in terms of rational planning, consciousness, intention, predictability, and necessity. Holistic approaches conceive coaction in terms of spontaneity, unconscious and unintended actions, non-predictability, chance. Dialectic approaches conceive co-action in terms of a unity of rational planning and spontaneous emergence, a unity of conscious and unconscious aspects and consequences, and a unity of necessity and chance. Co-operation in a strong sense that is employed in this paper means that actors work together, create a new emergent reality, have shared goals, all benefit from co-operating, can reach their goals in joint effort more quickly and more efficiently than on an individual basis, make concerted use of existing structures in order to produce new structures, learn from each other mutually, are interconnected in a social network, and are mutually dependent and responsible. There is a lack of cooperation, self-determination, inclusion and direct democracy in modern society due to its antagonistic

NEA international co-operative projects

International Nuclear Information System (INIS)

1989-01-01

This text is consecrated at the international co-operative projects of the OECD Nuclear Energy Agency (NEA) in the field of reactor safety (Halden reactor project, Loft project, studies on the damaged Three Mile Island unit-2 reactor, inspection of reactor steel components, incident reporting system) and in the field of radioactive waste management (Stripa project, geochemical data bases, Alligator river project, seabed disposal of high-level radioactive waste, decommissioning of nuclear facilities)

Effects of Dimers on Cooperation in the Spatial Prisoner's Dilemma Game

International Nuclear Information System (INIS)

Li Haihong; Cheng Hongyan; Dai Qionglin; Ju Ping; Yang Junzhong; Zhang Mei

2011-01-01

We investigate the evolutionary prisoner's dilemma game in structured populations by introducing dimers, which are defined as that two players in each dimer always hold a same strategy. We find that influences of dimers on cooperation depend on the type of dimers and the population structure. For those dimers in which players interact with each other, the cooperation level increases with the number of dimers though the cooperation improvement level depends on the type of network structures. On the other hand, the dimers, in which there are not mutual interactions, will not do any good to the cooperation level in a single community, but interestingly, will improve the cooperation level in a population with two communities. We explore the relationship between dimers and self-interactions and find that the effects of dimers are similar to that of self-interactions. Also, we find that the dimers, which are established over two communities in a multi-community network, act as one type of interaction through which information between communities is communicated by the requirement that two players in a dimer hold a same strategy. (general)

Energy Efficiency Analysis of a Two Dimensional Cooperative Wireless Sensor Network with Relay Selection

Directory of Open Access Journals (Sweden)

M. Kakitani

2013-06-01

Full Text Available The energy efficiency of non-cooperative and cooperative transmissions are investigated in a two-dimensional wireless sensor network, considering a target outage probability and the same end-to-end throughput for all transmission schemes. The impact of the relay selection method in the cooperative schemes is also analyzed. We show that under non line-of-sight conditions the relay selection method has a greater impact in the energy efficiency than the availability of a return channel. By its turn, under line-of-sight conditions a return channel is more valuable to the energy efficiency of cooperative transmission than the specific relay selection method. Finally, we demonstrate that the energy efficiency advantage of the cooperative over the non-cooperative transmission increases with the distance among nodes and with the nodes density.

Weakly coupled mean-field game systems

KAUST Repository

Gomes, Diogo A.; Patrizi, Stefania

2016-01-01

Here, we prove the existence of solutions to first-order mean-field games (MFGs) arising in optimal switching. First, we use the penalization method to construct approximate solutions. Then, we prove uniform estimates for the penalized problem

Discretisation Schemes for Level Sets of Planar Gaussian Fields

Science.gov (United States)

Beliaev, D.; Muirhead, S.

2018-01-01

Smooth random Gaussian functions play an important role in mathematical physics, a main example being the random plane wave model conjectured by Berry to give a universal description of high-energy eigenfunctions of the Laplacian on generic compact manifolds. Our work is motivated by questions about the geometry of such random functions, in particular relating to the structure of their nodal and level sets. We study four discretisation schemes that extract information about level sets of planar Gaussian fields. Each scheme recovers information up to a different level of precision, and each requires a maximum mesh-size in order to be valid with high probability. The first two schemes are generalisations and enhancements of similar schemes that have appeared in the literature (Beffara and Gayet in Publ Math IHES, 2017. https://doi.org/10.1007/s10240-017-0093-0; Mischaikow and Wanner in Ann Appl Probab 17:980-1018, 2007); these give complete topological information about the level sets on either a local or global scale. As an application, we improve the results in Beffara and Gayet (2017) on Russo-Seymour-Welsh estimates for the nodal set of positively-correlated planar Gaussian fields. The third and fourth schemes are, to the best of our knowledge, completely new. The third scheme is specific to the nodal set of the random plane wave, and provides global topological information about the nodal set up to `visible ambiguities'. The fourth scheme gives a way to approximate the mean number of excursion domains of planar Gaussian fields.

New co-operation agreement between CERN and JINR

CERN Multimedia

CERN Bulletin

2010-01-01

CERN Director-General Rolf Heuer (left) and JINR Director Alexei Sissakian (right). On Thursday 28 January, CERN Director-General Rolf Heuer and JINR Director Alexei Sissakian signed a new enlarged co-operation agreement to continue and enhance the scientific and technical co-operation of the two institutes in the field of high-energy physics. CERN and JINR have a long and successful history of collaboration extending back to the earliest days of their existence. The first informal meeting on international co-operation in the field of high-energy accelerators took place at CERN in 1959. It was attended by senior scientists from the United States, the USSR (including JINR) and CERN. Both JINR and CERN have played the role of a bridge between East and West for decades, contributing to the development of international scientific co-operation. In 1992 JINR signed a co-operation agreement with CERN that included an important number of protocols covering JINR’s participation in the construction of th...

General Relativistic Mean Field Theory for rotating nuclei

Energy Technology Data Exchange (ETDEWEB)

Madokoro, Hideki [Kyushu Univ., Fukuoka (Japan). Dept. of Physics; Matsuzaki, Masayuki

1998-03-01

The {sigma}-{omega} model Lagrangian is generalized to an accelerated frame by using the technique of general relativity which is known as tetrad formalism. We apply this model to the description of rotating nuclei within the mean field approximation, which we call General Relativistic Mean Field Theory (GRMFT) for rotating nuclei. The resulting equations of motion coincide with those of Munich group whose formulation was not based on the general relativistic transformation property of the spinor fields. Some numerical results are shown for the yrast states of the Mg isotopes and the superdeformed rotational bands in the A {approx} 60 mass region. (author)

Mean Field Game for Marriage

KAUST Repository

Bauso, Dario; Dia, Ben Mansour; Djehiche, Boualem; Tembine, Hamidou; Tempone, Raul

2014-01-01

The myth of marriage has been and is still a fascinating historical societal phenomenon. Paradoxically, the empirical divorce rates are at an all-time high. This work describes a unique paradigm for preserving relationships and marital stability from mean-field game theory. We show that optimizing the long-term well-being via effort and society feeling state distribution will help in stabilizing relationships.

Mean Field Game for Marriage

KAUST Repository

Bauso, Dario

2014-01-06

The myth of marriage has been and is still a fascinating historical societal phenomenon. Paradoxically, the empirical divorce rates are at an all-time high. This work describes a unique paradigm for preserving relationships and marital stability from mean-field game theory. We show that optimizing the long-term well-being via effort and society feeling state distribution will help in stabilizing relationships.

Mean Field Games for Stochastic Growth with Relative Utility

Energy Technology Data Exchange (ETDEWEB)

Huang, Minyi, E-mail: mhuang@math.carleton.ca [Carleton University, School of Mathematics and Statistics (Canada); Nguyen, Son Luu, E-mail: sonluu.nguyen@upr.edu [University of Puerto Rico, Department of Mathematics (United States)

2016-12-15

This paper considers continuous time stochastic growth-consumption optimization in a mean field game setting. The individual capital stock evolution is determined by a Cobb–Douglas production function, consumption and stochastic depreciation. The individual utility functional combines an own utility and a relative utility with respect to the population. The use of the relative utility reflects human psychology, leading to a natural pattern of mean field interaction. The fixed point equation of the mean field game is derived with the aid of some ordinary differential equations. Due to the relative utility interaction, our performance analysis depends on some ratio based approximation error estimate.

Mean Field Games for Stochastic Growth with Relative Utility

International Nuclear Information System (INIS)

Huang, Minyi; Nguyen, Son Luu

2016-01-01

This paper considers continuous time stochastic growth-consumption optimization in a mean field game setting. The individual capital stock evolution is determined by a Cobb–Douglas production function, consumption and stochastic depreciation. The individual utility functional combines an own utility and a relative utility with respect to the population. The use of the relative utility reflects human psychology, leading to a natural pattern of mean field interaction. The fixed point equation of the mean field game is derived with the aid of some ordinary differential equations. Due to the relative utility interaction, our performance analysis depends on some ratio based approximation error estimate.

Mean-field study of correlation-induced antisymmetric spin-orbit coupling in a two-orbital honeycomb model

Science.gov (United States)

Hayami, Satoru; Kusunose, Hiroaki; Motome, Yukitoshi

2018-05-01

We investigate a two-orbital Hubbard model on a honeycomb structure, with a special focus on the antisymmetric spin-orbit coupling (ASOC) induced by symmetry breaking in the electronic degrees of freedom. By investigating the ground-state phase diagram by the mean-field approximation in addition to the analysis in the strong correlation limit, we obtain a variety of symmetry-broken phases that induce different types of effective ASOCs by breaking of spatial inversion symmetry. We find several unusual properties emergent from the ASOCs, such as a linear magnetoelectric effect in a spin-orbital ordered phase at 1/4 filling and a spin splitting in the band structure in charge ordered phases at 1/4 and 1/2 fillings. We also show that a staggered potential on the honeycomb structure leads to another type of ASOC, which gives rise to a valley splitting in the band structure at 1/2 filling. We discuss the experimental relevance of our results to candidate materials including transition metal dichalcogenides and trichalcogenides.

Mean-field learning for satisfactory solutions

KAUST Repository

Tembine, Hamidou

2013-12-01

One of the fundamental challenges in distributed interactive systems is to design efficient, accurate, and fair solutions. In such systems, a satisfactory solution is an innovative approach that aims to provide all players with a satisfactory payoff anytime and anywhere. In this paper we study fully distributed learning schemes for satisfactory solutions in games with continuous action space. Considering games where the payoff function depends only on own-action and an aggregate term, we show that the complexity of learning systems can be significantly reduced, leading to the so-called mean-field learning. We provide sufficient conditions for convergence to a satisfactory solution and we give explicit convergence time bounds. Then, several acceleration techniques are used in order to improve the convergence rate. We illustrate numerically the proposed mean-field learning schemes for quality-of-service management in communication networks. © 2013 IEEE.

Threat and parochialism in intergroup relations: lab-in-the-field evidence from rural Georgia.

Science.gov (United States)

Schaub, Max

2017-10-25

Competition between groups is widely considered to foster cooperation within groups. Evidence from laboratory experiments hints at the existence of a proximate mechanism by which humans increase their level of cooperation with their ingroup when faced with an external threat. Further work suggests that ingroup cooperation should go along with aggressive behaviour towards the outgroup, although these theories are at odds with others that see high investments in outgroup relations as important means of stabilizing intergroup relations. Surprisingly, few of these arguments have been tested in the field, and existing studies are also limited by the lack of a direct measure of threat perception and aggressive behaviour. This study presents lab-in-the-field results from a rural context where exposure to an ethnic outgroup varies between villages. This context makes it possible to capture levels of threat perception, aggressive behaviour and cooperation without inducing intergroup competition artificially in the laboratory. All concepts are measured behaviourally. In- and outgroup cooperation was measured with a standard public goods game, and a novel experimental protocol was developed that measures perceived threat and aggressive behaviour: the threat game. The results show that levels of perceived threat, ingroup cooperation and aggressive behaviour are higher in regions more strongly exposed to ethnic outsiders. However, exposed regions also show high levels of outgroup cooperation and a concomitant lack of elevated ingroup bias. This pattern is explained by theorizing that communities show parochial altruism when faced with an ethnic outgroup, but balance aggressive behaviour with cooperative offers to diffuse tensions and to keep open channels of mutually beneficial exchange. © 2017 The Author(s).

The Two Meanings of Economic

Directory of Open Access Journals (Sweden)

Karl Polanyi

2012-07-01

Full Text Available In this text Karl Polanyi explains the two meanings of economic: the formal, which springs from the logical character of the means-ends relationship, and from which springs the scarcity definition of economic, and the substantive meaning, which points to the elemental fact that human beings, like all other living things, cannot exist for any length of time without a physical environment that sustains them. The two meanings, the formal and the substantive, have nothing in common. According to the author how solidly the two meanings were joined can be inferred from the ironic fate of the most controversial of modern mythological figures – economic man. Nel testo Karl Polanyi illustra i due significati di economico: il significato formale, che deriva dalla natura logica della relazione mezzi-fini e da cui discende la definizione di economico basata sulla scarsità, e il significato sostanziale, che rinvia al fatto che gli esseri umani, come tutti gli esseri viventi, non possono mantenersi in vita senza un ambiente materiale che li sostenga. I due significati non hanno nulla in comune. Secondo l’autore la solidità della congiunzione dei due termini si può capire dalla sorte ironica della più controversa fra le figure mitologiche moderne: l’uomo economico.

Deviations from cooperative growth mode during eutectoid transformation: Insights from a phase-field approach

International Nuclear Information System (INIS)

Ankit, Kumar; Mukherjee, Rajdip; Mittnacht, Tobias; Nestler, Britta

2014-01-01

The non-cooperative eutectoid transformation relies on the presence of pre-existing cementite particles in the parent austenitic phase and yields a product, popularly known as the divorced eutectoid. Under isothermal conditions, two of the important parameters that influence the transformation mechanism and determine the final morphology are undercooling (below the A 1 temperature) and interparticle spacing. Although the criteria that govern the morphological transition from lamellar to divorced is experimentally well established, numerical studies giving a detailed exposition of the non-cooperative transformation mechanism have not been reported extensively. In the present work, we employ a multiphase-field model that uses thermodynamic information from the CALPHAD database to numerically simulate the pulling-away of the advancing ferrite–austenite interface from cementite, which results in a transition from lamellar to divorced eutectoid morphology in Fe–C alloy. We also identify the onset of a concurrent growth and coarsening regime at small interparticle spacing and low undercooling. We analyze the simulation results to unravel the essential physics behind this complex spatial and temporal evolution pathway and amend the existing criteria by constructing a Lamellar-Divorced-Coarsening (LDC) map

Modification of linear response theory for mean-field approximations

NARCIS (Netherlands)

Hütter, M.; Öttinger, H.C.

1996-01-01

In the framework of statistical descriptions of many particle systems, the influence of mean-field approximations on the linear response theory is studied. A procedure, analogous to one where no mean-field approximation is involved, is used in order to determine the first order response of the

First-order, stationary mean-field games with congestion

KAUST Repository

Evangelista, David

2018-04-30

Mean-field games (MFGs) are models for large populations of competing rational agents that seek to optimize a suitable functional. In the case of congestion, this functional takes into account the difficulty of moving in high-density areas. Here, we study stationary MFGs with congestion with quadratic or power-like Hamiltonians. First, using explicit examples, we illustrate two main difficulties: the lack of classical solutions and the existence of areas with vanishing densities. Our main contribution is a new variational formulation for MFGs with congestion. With this formulation, we prove the existence and uniqueness of solutions. Finally, we consider applications to numerical methods.

First-order, stationary mean-field games with congestion

KAUST Repository

Evangelista, David; Ferreira, Rita; Gomes, Diogo A.; Nurbekyan, Levon; Voskanyan, Vardan K.

2018-01-01

Mean-field games (MFGs) are models for large populations of competing rational agents that seek to optimize a suitable functional. In the case of congestion, this functional takes into account the difficulty of moving in high-density areas. Here, we study stationary MFGs with congestion with quadratic or power-like Hamiltonians. First, using explicit examples, we illustrate two main difficulties: the lack of classical solutions and the existence of areas with vanishing densities. Our main contribution is a new variational formulation for MFGs with congestion. With this formulation, we prove the existence and uniqueness of solutions. Finally, we consider applications to numerical methods.

Fashion, Cooperation, and Social Interactions

Science.gov (United States)

Cao, Zhigang; Gao, Haoyu; Qu, Xinglong; Yang, Mingmin; Yang, Xiaoguang

2013-01-01

Fashion plays such a crucial rule in the evolution of culture and society that it is regarded as a second nature to the human being. Also, its impact on economy is quite nontrivial. On what is fashionable, interestingly, there are two viewpoints that are both extremely widespread but almost opposite: conformists think that what is popular is fashionable, while rebels believe that being different is the essence. Fashion color is fashionable in the first sense, and Lady Gaga in the second. We investigate a model where the population consists of the afore-mentioned two groups of people that are located on social networks (a spatial cellular automata network and small-world networks). This model captures two fundamental kinds of social interactions (coordination and anti-coordination) simultaneously, and also has its own interest to game theory: it is a hybrid model of pure competition and pure cooperation. This is true because when a conformist meets a rebel, they play the zero sum matching pennies game, which is pure competition. When two conformists (rebels) meet, they play the (anti-) coordination game, which is pure cooperation. Simulation shows that simple social interactions greatly promote cooperation: in most cases people can reach an extraordinarily high level of cooperation, through a selfish, myopic, naive, and local interacting dynamic (the best response dynamic). We find that degree of synchronization also plays a critical role, but mostly on the negative side. Four indices, namely cooperation degree, average satisfaction degree, equilibrium ratio and complete ratio, are defined and applied to measure people’s cooperation levels from various angles. Phase transition, as well as emergence of many interesting geographic patterns in the cellular automata network, is also observed. PMID:23382799

A Dosimetric Evaluation of Conventional Helmet Field Irradiation Versus Two-Field Intensity-Modulated Radiotherapy Technique

International Nuclear Information System (INIS)

Yu, James B.; Shiao, Stephen L.; Knisely, Jonathan

2007-01-01

Purpose: To compare dosimetric differences between conventional two-beam helmet field irradiation (external beam radiotherapy, EBRT) of the brain and a two-field intensity-modulated radiotherapy (IMRT) technique. Methods and Materials: Ten patients who received helmet field irradiation at our institution were selected for study. External beam radiotherapy portals were planned per usual practice. Intensity-modulated radiotherapy fields were created using the identical field angles as the EBRT portals. Each brain was fully contoured along with the spinal cord to the bottom of the C2 vertebral body. This volume was then expanded symmetrically by 0.5 cm to construct the planning target volume. An IMRT plan was constructed using uniform optimization constraints. For both techniques, the nominal prescribed dose was 3,000 cGy in 10 fractions of 300 cGy using 6-MV photons. Comparative dose-volume histograms were generated for each patient and analyzed. Results: Intensity-modulated radiotherapy improved dose uniformity over EBRT for whole brain radiotherapy. The mean percentage of brain receiving >105% of dose was reduced from 29.3% with EBRT to 0.03% with IMRT. The mean maximum dose was reduced from 3,378 cGy (113%) for EBRT to 3,162 cGy (105%) with IMRT. The mean percent volume receiving at least 98% of the prescribed dose was 99.5% for the conventional technique and 100% for IMRT. Conclusions: Intensity-modulated radiotherapy reduces dose inhomogeneity, particularly for the midline frontal lobe structures where hot spots occur with conventional two-field EBRT. More study needs to be done addressing the clinical implications of optimizing dose uniformity and its effect on long-term cognitive function in selected long-lived patients

Fluorescent lamp with static magnetic field generating means

Science.gov (United States)

Moskowitz, P.E.; Maya, J.

1987-09-08

A fluorescent lamp wherein magnetic field generating means (e.g., permanent magnets) are utilized to generate a static magnetic field across the respective electrode structures of the lamp such that maximum field strength is located at the electrode's filament. An increase in efficacy during operation has been observed. 2 figs.

First Graders' Interpersonal Understanding during Cooperative and Competitive Games

Science.gov (United States)

Zan, Betty; Hildebrandt, Carolyn

2003-01-01

Differences in children's social interactions during cooperative and competitive games were investigated. Thirty-seven children from two first grade classes with cooperative classroom climates were videotaped while playing a cooperative and a competitive board game. Children's social interactions were coded using Selman's Levels of Enacted…

Comparisons of treatment means when factors do not interact in two-factorial studies

KAUST Repository

Wei, Jiawei; Carroll, Raymond J.; Harden, Kathryn K.; Wu, Guoyao

2011-01-01

Scientists in the fields of nutrition and other biological sciences often design factorial studies to test the hypotheses of interest and importance. In the case of two-factorial studies, it is widely recognized that the analysis of factor effects is generally based on treatment means when the interaction of the factors is statistically significant, and involves multiple comparisons of treatment means. However, when the two factors do not interact, a common understanding among biologists is that comparisons among treatment means cannot or should not be made. Here, we bring this misconception into the attention of researchers. Additionally, we indicate what kind of comparisons among the treatment means can be performed when there is a nonsignificant interaction among two factors. Such information should be useful in analyzing the experimental data and drawing meaningful conclusions.

Comparisons of treatment means when factors do not interact in two-factorial studies

KAUST Repository

Wei, Jiawei

2011-05-06

Scientists in the fields of nutrition and other biological sciences often design factorial studies to test the hypotheses of interest and importance. In the case of two-factorial studies, it is widely recognized that the analysis of factor effects is generally based on treatment means when the interaction of the factors is statistically significant, and involves multiple comparisons of treatment means. However, when the two factors do not interact, a common understanding among biologists is that comparisons among treatment means cannot or should not be made. Here, we bring this misconception into the attention of researchers. Additionally, we indicate what kind of comparisons among the treatment means can be performed when there is a nonsignificant interaction among two factors. Such information should be useful in analyzing the experimental data and drawing meaningful conclusions.

Using vibrational Cooper minima to determine strong-field molecular-dissociation pathways

Science.gov (United States)

Severt, T.; Zohrabi, M.; Armstrong, G. S. J.; McKenna, J.; Gaire, B.; Kling, Nora G.; Ablikim, U.; Carnes, K. D.; Esry, B. D.; Ben-Itzhak, I.

2015-05-01

We explore the possibility of using vibrational ``Cooper minima'' (VCM) locations as a method to determine dissociation pathways of molecules in a strong laser field. As a test case, we study the laser-induced dissociation of an O2+ion beam by several wavelengths (λ = 800 , 400, and 266 nm) using a coincidence three-dimensional momentum imaging technique. Vibrational structure is observed in the kinetic energy release spectra, revealing a suppression of the dissociation of certain vibrational levels, which is a manifestation of the VCM effect. Previously, it has been shown in H2+that first-order time-dependent perturbation theory can be used to predict the locations of the VCM. We explore if the VCM locations predicted by perturbation theory can help uniquely identify dissociation pathways in O2+and consider its utility for other systems. Supported by the Chemical Sciences, Geosciences, and Biosciences Division, Office of Basic Energy Sciences, Office of Science, U.S. Department of Energy. TS was partially supported by NSF-REU under Grant No. PHY-0851599.

The emergence of cooperation in tie strength models

International Nuclear Information System (INIS)

Xu, Bo; Yue, Yunpeng

2016-01-01

In this paper, we propose a tie strength model to explain the emergence of cooperation in spatial prisoner's dilemma games, assuming that cooperators preferentially allocate their investments to friends with strong ties. Two types of prisoner's dilemma models are examined in this study: the traditional two-strategy model considering only cooperators and defectors; the expanded three-strategy model consisting cooperators, defectors and extortioners. The results show that tie strength model contributes to the promotion of cooperation in both types of prisoner's dilemma games. However, we point out that the influence of the investment preference is quite different in the two prisoner's dilemma game settings. In the two-strategy prisoner's dilemma game, only small preference contributes to the promotion of cooperation. Once this preference exceeds a critical value, cooperation will be prohibited. We explain this phenomenon by arguing that extremely strong investment preference undermines the ability of cooperative clusters to resist defectors. Moreover, we extend the analysis into the three-strategy case and discover that the catalytic effect of extortioners can eliminate this first up and then down trend in the two-strategy model. The equilibrium fraction of cooperators is always positively correlated to the level of investment preference in three-strategy models.

Regional long-term co-operation in the field of nuclear and radiation emergency preparedness

International Nuclear Information System (INIS)

Sladek, V.; Metke, E.; Janko, K.; Hohenberg, J. K.; Hofer, P.

2004-01-01

Emergency preparedness is generally covered by methodical and coordinative activities of the International Atomic Energy Agency (IAEA) in Member States of the IAEA and by the European Commission (EC) in EU Member and EU Accession Countries. However, the regional harmonisation of emergency arrangements is an important trend of emergency preparedness. The present paper gives a couple of illustrative examples for a regional co-operation in the field of emergency preparedness in Central Europe and an overview on international exercises in this region. The penultimate section contains an outlook on future activities regarding regional co-operation in Central Europe. The following topics have been suggested inter alia: the harmonisation of intervention criteria and countermeasures, co-ordination in the field of information of the public, comprehensive bi lateral and multilateral exercises, exchange of experts between the national nuclear emergency centres and inter-comparison calculations of the computer codes. (authors)

The application of mean field theory to image motion estimation.

Science.gov (United States)

Zhang, J; Hanauer, G G

1995-01-01

Previously, Markov random field (MRF) model-based techniques have been proposed for image motion estimation. Since motion estimation is usually an ill-posed problem, various constraints are needed to obtain a unique and stable solution. The main advantage of the MRF approach is its capacity to incorporate such constraints, for instance, motion continuity within an object and motion discontinuity at the boundaries between objects. In the MRF approach, motion estimation is often formulated as an optimization problem, and two frequently used optimization methods are simulated annealing (SA) and iterative-conditional mode (ICM). Although the SA is theoretically optimal in the sense of finding the global optimum, it usually takes many iterations to converge. The ICM, on the other hand, converges quickly, but its results are often unsatisfactory due to its "hard decision" nature. Previously, the authors have applied the mean field theory to image segmentation and image restoration problems. It provides results nearly as good as SA but with much faster convergence. The present paper shows how the mean field theory can be applied to MRF model-based motion estimation. This approach is demonstrated on both synthetic and real-world images, where it produced good motion estimates.

Leveling the field: The role of training, safety programs, and knowledge management systems in fostering inclusive field settings

Science.gov (United States)

Starkweather, S.; Crain, R.; Derry, K. R.

2017-12-01

Knowledge is empowering in all settings, but plays an elevated role in empowering under-represented groups in field research. Field research, particularly polar field research, has deep roots in masculinized and colonial traditions, which can lead to high barriers for women and minorities (e.g. Carey et al., 2016). While recruitment of underrepresented groups into polar field research has improved through the efforts of organizations like the Association of Polar Early Career Scientists (APECS), the experiences and successes of these participants is often contingent on the availability of specialized training opportunities or the quality of explicitly documented information about how to survive Arctic conditions or how to establish successful measurement protocols in harsh environments. In Arctic field research, knowledge is often not explicitly documented or conveyed, but learned through "experience" or informally through ad hoc advice. The advancement of field training programs and knowledge management systems suggest two means for unleashing more explicit forms of knowledge about field work. Examples will be presented along with a case for how they level the playing field and improve the experience of field work for all participants.

Effect of initial fraction of cooperators on cooperative behavior in evolutionary prisoner's dilemma game.

Directory of Open Access Journals (Sweden)

Keizo Shigaki

Full Text Available We investigate the influence of initial fraction of cooperators on the evolution of cooperation in spatial prisoner's dilemma games. Compared with the results of heterogeneous networks, we find that there is a relatively low initial fraction of cooperators to guarantee higher equilibrium cooperative level. While this interesting phenomenon is contrary to the commonly shared knowledge that higher initial fraction of cooperators can provide better environment for the evolution of cooperation. To support our outcome, we explore the time courses of cooperation and find that the whole course can be divided into two sequent stages: enduring (END and expanding (EXP periods. At the end of END period, thought there is a limited number of cooperator clusters left for the case of low initial setup, these clusters can smoothly expand to hold the whole system in the EXP period. However, for high initial fraction of cooperators, superfluous cooperator clusters hinder their effective expansion, which induces many remaining defectors surrounding the cooperator clusters. Moreover, through intensive analysis, we also demonstrate that when the tendency of three cooperation cluster characteristics (cluster size, cluster number and cluster shape are consistent within END and EXP periods, the state that maximizes cooperation can be favored.

Cooperation between Russia and the EU in the field of innovative development of tourism: the case of the Lithuania — Poland — Russia cross-border cooperation programme

Directory of Open Access Journals (Sweden)

Kropinova Elena

2013-12-01

Full Text Available To study the key instruments of international cooperation between Russia and the European Union aimed at stimulating innovative development of tourism co-financed by the EU and Russia. The author describes specific projects implemented in the framework of the Lithuania-Poland-Russia cross-border cooperation programme for 2009—2013 in the field of tourism. Special attention is paid to analysing tourism innovations that have emerged as a result of the projects aimed at cooperation and tourism development in the border regions of Russia and the EU countries. A number of projects have been implemented under the supervision and with the participation of the author. The article focuses on the role of innovative types of tourism in the regional development of territories in the case of the Kaliningrad region. The current approaches to defining tourism innovations in Russian and international studies are not comprehensive and do not reflect the essence of innovative processes. Innovative development is often reduced to the introduction of new information technologies, i. e. informatization replaces innovative development. However, it is important to take into account other innovative tools: for instance, interactive network museums in developing innovative tourist attraction objects, e-marketing in introducing innovations in tourist product promotion, programmes of private- public partnership in the field of public regulation and tourism stimulation, etc. These technologies contribute to the transition fr om a certain economic agent, the industry as a whole, or a tourist destination to a fundamentally new level in terms of tourist product presentation and increase of competitiveness. The sources for innovations in tourism are both the providers and consumers of tourist services. In those regions wh ere tourism is considered an economic priority, local authorities and even super-governmental organisations, such as the European Commission (through

Cooperation between Russia and the EU in the field of innovative development of tourism: the case of the Lithuania — Poland — Russia cross-border cooperation programme

Directory of Open Access Journals (Sweden)

Kropinova Elena

2013-01-01

Full Text Available To study the key instruments of international cooperation between Russia and the European Union aimed at stimulating innovative development of tourism co-financed by the EU and Russia. The author describes specific projects implemented in the framework of the Lithuania-Poland-Russia cross-border cooperation programme for 2009—2013 in the field of tourism. Special attention is paid to analysing tourism innovations that have emerged as a result of the projects aimed at cooperation and tourism development in the border regions of Russia and the EU countries. A number of projects have been implemented under the supervision and with the participation of the author. The article focuses on the role of innovative types of tourism in the regional development of territories in the case of the Kaliningrad region. The current approaches to defining tourism innovations in Russian and international studies are not comprehensive and do not reflect the essence of innovative processes. Innovative development is often reduced to the introduction of new information technologies, i. e. informatization replaces innovative development. However, it is important to take into account other innovative tools: for instance, interactive network museums in developing innovative tourist attraction objects, e-marketing in introducing innovations in tourist product promotion, programmes of private- public partnership in the field of public regulation and tourism stimulation, etc. These technologies contribute to the transition fr om a certain economic agent, the industry as a whole, or a tourist destination to a fundamentally new level in terms of tourist product presentation and increase of competitiveness. The sources for innovations in tourism are both the providers and consumers of tourist services. In those regions wh ere tourism is considered an economic priority, local authorities and even super-governmental organisations, such as the European Commission (through

Crossing rule for a PT-symmetric two-level time-periodic system

International Nuclear Information System (INIS)

Moiseyev, Nimrod

2011-01-01

For a two-level system in a time-periodic field we show that in the non-Hermitian PT case the level crossing is of two quasistationary states that have the same dynamical symmetry property. At the field's parameters where the two levels which have the same dynamical symmetry cross, the corresponding quasienergy states coalesce and a self-orthogonal state is obtained. This situation is very different from the Hermitian case where a crossing of two quasienergy levels happens only when the corresponding two quasistationary states have different dynamical symmetry properties and, unlike the situation in the non-Hermitian case, the spectrum remains complete also when the two levels cross.

Mean field theory of nuclei and shell model. Present status and future outlook

International Nuclear Information System (INIS)

Nakada, Hitoshi

2003-01-01

functions and halos, magic numbers of unstable nuclei, mean field shell model and cluster structure, and problems concerning effective interactions. An overview of numerical calculation is presented at the end with two subtitles: Hartree-Fock calculation, and shell model calculation. (S. Funahashi)

Non-invasive assessment of glucocorticoid and androgen metabolite levels in cooperatively breeding Damaraland mole-rats (Fukomys damarensis).

Science.gov (United States)

Medger, Katarina; Bennett, Nigel C; Lutermann, Heike; Ganswindt, Andre

2018-05-18

Dominant females of cooperative breeding species often use aggression to suppress reproduction of subordinate females, resulting in subordinates experiencing stress-related increases in glucocorticoid levels, which may cause reproductive down-regulation. This would suggest a general pattern with higher glucocorticoid levels in subordinate compared to dominant individuals; however, the opposite was found in a number of cooperatively breeding species. Furthermore, breeding females of the cooperatively breeding Damaraland mole-rats (Fukomys damarensis) exhibit very high androgen concentrations during the wet season, presumably to support their breeding monopoly. Hormone analysis in Damaraland mole-rats have typically been measured using plasma and urine, but faecal analysis offers additional advantages especially for field studies on this species. The present study examines the suitability of Damaraland mole-rat faecal samples for determining glucocorticoid metabolite (fGCM) and androgen metabolite (fAM) concentrations using enzyme immunoassays. Using these assays, we further evaluated the effects of breeding status on fGCM and fAM concentrations in wild-caught and captive Damaraland mole-rats. Wild-caught breeding and non-breeding males and females exhibited no differences in fAM concentrations. Immunoreactive fGCM concentrations were only high in male breeders and comparatively low in non-breeders and breeding females. Concentrations of fAMs and fGCMs were similar in captive males and females, but fAM concentrations were elevated in captive compared to wild-caught individuals, which may be related to a higher reproductive activity due to removal from the breeding female. The relatively uniform fAM and fGCM concentrations found in wild-caught mole-rats may be explained by a stable colony structure during the dry season during which this study was conducted. Limited dispersal opportunities result in lower aggression and stress levels within a colony and as a result

Proceedings from the technical workshop on near-field performance assessment for high-level waste

International Nuclear Information System (INIS)

Sellin, P.; Apted, M.; Gago, J.

1991-12-01

This report contains the proceedings of 'Technical workshop of near-filed performance assessment for high-level waste' held in Madrid October 15-17, 1990. It includes the invited presentations and summaries of the scientific discussions. The workshop covered several topics: * post-emplacement environment, * benchmarking of computer codes, * glass release, * spent-fuel release, * radionuclide solubility, * near-field transport processes, * coupled processes in the near-field, * integrated assessments, * sensitivity analyses and validation. There was an invited presentation on each topic followed by an extensive discussion. One of the points highlighted in the closing discussion of the workshop was the need for international cooperation in the field of near-field performance assessment. The general opinion was that this was best achieved in smaller groups discussing specific questions. (au) Separate abstracts were prepared for 9 papers in this volume

High-level radioactive waste management. A means to social consensus

International Nuclear Information System (INIS)

Pierce, B.; Hill, D.

1984-01-01

The problem of safely disposing of high-level radioactive waste is not new, but it is becoming more pressing as the temporary storage facilities of public utilities run out. The technical questions of how best to immobilize these wastes for many centuries have been studied for years and many feel that these problems are solved, or nearly so. In the USA many states have set up roadblocks to the federal waste management programme, however, and it is clear that social consensus must be reached for any waste disposal programme to be successful. The Nuclear Waste Policy Act of 1982 provides a long needed framework for reaching this consensus, giving the states unprecedented access to federal decision making. The rights of the states in a process of co-operation and consultation are clearly defined by the Act, but the means by which the states exercise these rights are left entirely to them. We examine the structures, methods and goals open to the states, and recommend a rationale for the state decision process defining the roles of the governor and legislature. (author)

High-level radioactive wste management: a means to social consensus

International Nuclear Information System (INIS)

Pierce, B.; Hill, D.; Haefele, E.T.

1983-01-01

The problem of safely disposing of high-level radioactive waste is not new, but it is becoming more pressing as the temporary storage facilities of public utilities run out. The technical questions of how best to immobilize these wastes for many centuries have been studied for years and many feel that these problems are solved, or nearly so. Many states have set up roadblocks to the federal waste management program, however, and it is clear that social consensus must be reached for any waste disposal program to be successful. The Nuclear Waste Policy Act of 1982 provides a long-needed framework for reaching this consensus, giving the states unprecedented access to federal decision-making. The rights of the states in a process of cooperation and consultation are clearly defined by the Act, but the means by which the states exercise those rights are left entirely to them. We examine the structures, methods, and goals open to the states, and recommend a rationale for the state decision process defining the roles of the governor and legislature

Exact Landau levels in two-dimensional electron systems with Rashba and Dresselhaus spin-orbit interactions in a perpendicular magnetic field

International Nuclear Information System (INIS)

Zhang Degang

2006-01-01

We study a two-dimensional electron system in the presence of both Rashba and Dresselhaus spin-orbit interactions in a perpendicular magnetic field. Defining two suitable boson operators and using the unitary transformations we are able to obtain the exact Landau levels in the range of all the parameters. When the strengths of the Rashba and Dresselhaus spin-orbit interactions are equal, a new analytical solution for the vanishing Zeeman energy is found, where the orbital and spin wavefunctions of the electron are separated. It is also shown that in this case the Zeeman and spin-orbit splittings are independent of the Landau level index n. Due to the Zeeman energy, new crossing between the eigenstates vertical bar n, k, s = 1, σ) and vertical bar n + 1, k, s' = -1, σ') is produced at a certain magnetic field for larger Rashba spin-orbit coupling. This degeneracy leads to a resonant spin Hall conductance if it happens at the Fermi level. (letter to the editor)

CTBT verification-related technologies for peaceful purposes: the French experiences of international cooperation

International Nuclear Information System (INIS)

Massinon, B.

1999-01-01

The French experience concerning CTBT verification-related technologies for peaceful purposes as well a the international cooperation in this field are presented. Possible objectives and cooperation program needs are cited. French experience in international cooperation is related to seismology and seismic hazards in Bolivia, Madagascar, Nepal and Indonesia and is considered as very constructive, meaning that technical experience is developed, consistent scientific results are obtained, and a considerable yield to the CTBT task is achieved. Large scientific benefits are expected from the CTBTO

A Maximum Principle for SDEs of Mean-Field Type

Energy Technology Data Exchange (ETDEWEB)

Andersson, Daniel, E-mail: danieand@math.kth.se; Djehiche, Boualem, E-mail: boualem@math.kth.se [Royal Institute of Technology, Department of Mathematics (Sweden)

2011-06-15

We study the optimal control of a stochastic differential equation (SDE) of mean-field type, where the coefficients are allowed to depend on some functional of the law as well as the state of the process. Moreover the cost functional is also of mean-field type, which makes the control problem time inconsistent in the sense that the Bellman optimality principle does not hold. Under the assumption of a convex action space a maximum principle of local form is derived, specifying the necessary conditions for optimality. These are also shown to be sufficient under additional assumptions. This maximum principle differs from the classical one, where the adjoint equation is a linear backward SDE, since here the adjoint equation turns out to be a linear mean-field backward SDE. As an illustration, we apply the result to the mean-variance portfolio selection problem.

A Maximum Principle for SDEs of Mean-Field Type

International Nuclear Information System (INIS)

Andersson, Daniel; Djehiche, Boualem

2011-01-01

We study the optimal control of a stochastic differential equation (SDE) of mean-field type, where the coefficients are allowed to depend on some functional of the law as well as the state of the process. Moreover the cost functional is also of mean-field type, which makes the control problem time inconsistent in the sense that the Bellman optimality principle does not hold. Under the assumption of a convex action space a maximum principle of local form is derived, specifying the necessary conditions for optimality. These are also shown to be sufficient under additional assumptions. This maximum principle differs from the classical one, where the adjoint equation is a linear backward SDE, since here the adjoint equation turns out to be a linear mean-field backward SDE. As an illustration, we apply the result to the mean-variance portfolio selection problem.

Parametric resonances in the amplitude-modulated probe-field absorption spectrum of a two-level atom driven by a resonance amplitude- and phase-modulated pumping field

International Nuclear Information System (INIS)

Sushilov, N.V.; Kholodkevich, E.D.

1995-01-01

An analytical expression is derived for the polarization induced by a weak probe field with periodically modulated amplitude in a two-level medium saturated by a strong amplitude-and phase-modulated resonance field. It is shown that the absorption spectrum of the probe field includes parametric resonances, the maxima corresponding to the condition δ= 2nΓ-Ω w and the minima to that of δ= (2n + 1)Γ- w , where δ is the probe-field detuning front the resonance frequency, Ω w is the modulation frequency of the probe-field amplitude, and Γ is the transition line width, n = 1, 2, 3, hor-ellipsis. At the specific modulation parameters, a substantial region of negative values (i.e., the region of amplification without the population inversion) exists in the absorption spectrum of the probe field

Dark-Bright Soliton Dynamics Beyond the Mean-Field Approximation

Science.gov (United States)

Katsimiga, Garyfallia; Koutentakis, Georgios; Mistakidis, Simeon; Kevrekidis, Panagiotis; Schmelcher, Peter; Theory Group of Fundamental Processes in Quantum Physics Team

2017-04-01

The dynamics of dark bright solitons beyond the mean-field approximation is investigated. We first examine the case of a single dark-bright soliton and its oscillations within a parabolic trap. Subsequently, we move to the setting of collisions, comparing the mean-field approximation to that involving multiple orbitals in both the dark and the bright component. Fragmentation is present and significantly affects the dynamics, especially in the case of slower solitons and in that of lower atom numbers. It is shown that the presence of fragmentation allows for bipartite entanglement between the distinguishable species. Most importantly the interplay between fragmentation and entanglement leads to the decay of each of the initial mean-field dark-bright solitons into fast and slow fragmented dark-bright structures. A variety of excitations including dark-bright solitons in multiple (concurrently populated) orbitals is observed. Dark-antidark states and domain-wall-bright soliton complexes can also be observed to arise spontaneously in the beyond mean-field dynamics. Deutsche Forschungsgemeinschaft (DFG) in the framework of the SFB 925 ``Light induced dynamics and control of correlated quantum systems''.

Two-dimensional atom localization via probe absorption in a four-level atomic system

International Nuclear Information System (INIS)

Wang Zhi-Ping; Ge Qiang; Ruan Yu-Hua; Yu Ben-Li

2013-01-01

We have investigated the two-dimensional (2D) atom localization via probe absorption in a coherently driven four-level atomic system by means of a radio-frequency field driving a hyperfine transition. It is found that the detecting probability and precision of 2D atom localization can be significantly improved via adjusting the system parameters. As a result, our scheme may be helpful in laser cooling or the atom nano-lithography via atom localization

Classification of hemispheric monthly mean stratospheric potential vorticity fields

Directory of Open Access Journals (Sweden)

R. Huth

Full Text Available Monthly mean NCEP reanalysis potential vorticity fields at the 650 K isentropic level over the Northern and Southern Hemispheres between 1979 and 1997 were studied using multivariate analysis tools. Principal component analysis in the T-mode was applied to demonstrate the validity of such statistical techniques for the study of stratospheric dynamics and climatology. The method, complementarily applied to both the raw and anomaly fields, was useful in determining and classifying the characteristics of winter and summer PV fields on both hemispheres, in particular, the well-known differences in the behaviour and persistence of the polar vortices. It was possible to identify such features as sudden warming events in the Northern Hemisphere and final warming dates in both hemispheres. The stratospheric impact of other atmospheric processes, such as volcanic eruptions, also identified though the results, must be viewed at this stage as tentative. An interesting change in behaviour around 1990 was detected over both hemispheres.

Key words. Meteorology and atmospheric dynamics (middle atmosphere dynamics; general circulation; climatology

ENERGETIC PARTICLE TRANSPORT ACROSS THE MEAN MAGNETIC FIELD: BEFORE DIFFUSION

International Nuclear Information System (INIS)

Laitinen, T.; Dalla, S.

2017-01-01

Current particle transport models describe the propagation of charged particles across the mean field direction in turbulent plasmas as diffusion. However, recent studies suggest that at short timescales, such as soon after solar energetic particle (SEP) injection, particles remain on turbulently meandering field lines, which results in nondiffusive initial propagation across the mean magnetic field. In this work, we use a new technique to investigate how the particles are displaced from their original field lines, and we quantify the parameters of the transition from field-aligned particle propagation along meandering field lines to particle diffusion across the mean magnetic field. We show that the initial decoupling of the particles from the field lines is slow, and particles remain within a Larmor radius from their initial meandering field lines for tens to hundreds of Larmor periods, for 0.1–10 MeV protons in turbulence conditions typical of the solar wind at 1 au. Subsequently, particles decouple from their initial field lines and after hundreds to thousands of Larmor periods reach time-asymptotic diffusive behavior consistent with particle diffusion across the mean field caused by the meandering of the field lines. We show that the typical duration of the prediffusive phase, hours to tens of hours for 10 MeV protons in 1 au solar wind turbulence conditions, is significant for SEP propagation to 1 au and must be taken into account when modeling SEP propagation in the interplanetary space.

ENERGETIC PARTICLE TRANSPORT ACROSS THE MEAN MAGNETIC FIELD: BEFORE DIFFUSION

Energy Technology Data Exchange (ETDEWEB)

Laitinen, T.; Dalla, S., E-mail: tlmlaitinen@uclan.ac.uk [Jeremiah Horrocks Institute, University of Central Lancashire, Preston (United Kingdom)

2017-01-10

Current particle transport models describe the propagation of charged particles across the mean field direction in turbulent plasmas as diffusion. However, recent studies suggest that at short timescales, such as soon after solar energetic particle (SEP) injection, particles remain on turbulently meandering field lines, which results in nondiffusive initial propagation across the mean magnetic field. In this work, we use a new technique to investigate how the particles are displaced from their original field lines, and we quantify the parameters of the transition from field-aligned particle propagation along meandering field lines to particle diffusion across the mean magnetic field. We show that the initial decoupling of the particles from the field lines is slow, and particles remain within a Larmor radius from their initial meandering field lines for tens to hundreds of Larmor periods, for 0.1–10 MeV protons in turbulence conditions typical of the solar wind at 1 au. Subsequently, particles decouple from their initial field lines and after hundreds to thousands of Larmor periods reach time-asymptotic diffusive behavior consistent with particle diffusion across the mean field caused by the meandering of the field lines. We show that the typical duration of the prediffusive phase, hours to tens of hours for 10 MeV protons in 1 au solar wind turbulence conditions, is significant for SEP propagation to 1 au and must be taken into account when modeling SEP propagation in the interplanetary space.

Spectral density of Cooper pairs in two level quantum dot–superconductors Josephson junction

Energy Technology Data Exchange (ETDEWEB)

Dhyani, A., E-mail: archana.d2003@gmail.com [Department of Physics, University of Petroleum and Energy Studies, Dehradun 248007, Uttarakhand (India); Rawat, P.S. [Department of Nuclear Science and Technology, University of Petroleum and Energy Studies, Dehradun 248007, Uttarakhand (India); Tewari, B.S., E-mail: bstewari@ddn.upes.ac.in [Department of Physics, University of Petroleum and Energy Studies, Dehradun 248007, Uttarakhand (India)

2016-09-15

Highlights: • The present work deals with the study of the electronic spectral density of electron pairs and its effect in charge transport in superconductor-quantum dot-superconductor junctions. • The charge transfer across such junctions can be controlled by changing the positions of the dot level. • The Josephson supercurrent can also be tuned by controlling the position of quantum dot energy levels. - Abstract: In the present paper, we report the role of quantum dot energy levels on the electronic spectral density for a two level quantum dot coupled to s-wave superconducting leads. The theoretical arguments in this work are based on the Anderson model so that it necessarily includes dot energies, single particle tunneling and superconducting order parameter for BCS superconductors. The expression for single particle spectral function is obtained by using the Green's function equation of motion technique. On the basis of numerical computation of spectral function of superconducting leads, it has been found that the charge transfer across such junctions can be controlled by the positions and availability of the dot levels.

Stability of various entanglements in the interaction between two two-level atoms with a quantized field under the influences of several decay sources

Science.gov (United States)

Valizadeh, Sh.; Tavassoly, M. K.; Yazdanpanah, N.

2018-02-01

In this paper the interaction between two two-level atoms with a single-mode quantized field is studied. To achieve exact information about the physical properties of the system, one should take into account various sources of dissipation such as photon leakage of cavity, spontaneous emission rate of atoms, internal thermal radiation of cavity and dipole-dipole interaction between the two atoms. In order to achieve the desired goals, we obtain the time evolution of the associated density operator by solving the time-dependent Lindblad equation corresponding to the system. Then, we evaluate the temporal behavior of total population inversion and quantum entanglement between the evolved subsystems, numerically. We clearly show that how the damping parameters affect on the dynamics of considered properties. By analyzing the numerical results, we observe that increasing each of the damping sources leads to faster decay of total population inversion. Also, it is observed that, after starting the interaction, the entanglement between one atom with other parts of the system as well as the entanglement between "atom-atom" subsystem and the "field", tend to some constant values very soon. Moreover, the stable values of entanglement are reduced via increasing the damping factor Γ A (ΓA^{(1)} = ΓA^{(2)} = ΓA ) where ΓA is the spontaneous emission rate of each atom. In addition, we find that by increasing the thermal photons, the entropies (entanglements) tend sooner to some increased stable values. Accordingly, we study the atom-atom entanglement by evaluating the concurrence under the influence of dissipation sources, too. At last, the effects of dissipation sources on the genuine tripartite entanglement between the three subsystems include of two two-level atoms and a quantized field are numerically studied. Due to the important role of stationary entanglement in quantum information processing, our results may provide useful hints for practical protocols which require

Nonlinear Jaynes–Cummings model for two interacting two-level atoms

International Nuclear Information System (INIS)

Santos-Sánchez, O de los; González-Gutiérrez, C; Récamier, J

2016-01-01

In this work we examine a nonlinear version of the Jaynes–Cummings model for two identical two-level atoms allowing for Ising-like and dipole–dipole interplays between them. The model is said to be nonlinear in the sense that it can incorporate both a general intensity-dependent interaction between the atomic system and the cavity field and/or the presence of a nonlinear medium inside the cavity. As an example, we consider a particular type of atom-field coupling based upon the so-called Buck–Sukumar model and a lossless Kerr-like cavity. We describe the possible effects of such features on the evolution of some quantities of current interest, such as atomic excitation, purity, concurrence, the entropy of the field and the evolution of the latter in phase space. (paper)

Entanglement Criteria of Two Two-Level Atoms Interacting with Two Coupled Modes

Science.gov (United States)

Baghshahi, Hamid Reza; Tavassoly, Mohammad Kazem; Faghihi, Mohammad Javad

2015-08-01

In this paper, we study the interaction between two two-level atoms and two coupled modes of a quantized radiation field in the form of parametric frequency converter injecting within an optical cavity enclosed by a medium with Kerr nonlinearity. It is demonstrated that, by applying the Bogoliubov-Valatin canonical transformation, the introduced model is reduced to a well-known form of the generalized Jaynes-Cummings model. Then, under particular initial conditions for the atoms (in a coherent superposition of its ground and upper states) and the fields (in a standard coherent state) which may be prepared, the time evolution of state vector of the entire system is analytically evaluated. In order to understand the degree of entanglement between subsystems (atom-field and atom-atom), the dynamics of entanglement through different measures, namely, von Neumann reduced entropy, concurrence and negativity is evaluated. In each case, the effects of Kerr nonlinearity and detuning parameter on the above measures are numerically analyzed, in detail. It is illustrated that the amount of entanglement can be tuned by choosing the evolved parameters, appropriately.

Optimal Control of Holding Motion by Nonprehensile Two-Cooperative-Arm Robot

Directory of Open Access Journals (Sweden)

Changan Jiang

2016-01-01

Full Text Available Recently, more researchers have focused on nursing-care assistant robot and placed their hope on it to solve the shortage problem of the caregivers in hospital or nursing home. In this paper, a nonprehensile two-cooperative-arm robot is considered to realize holding motion to keep a two-rigid-link object (regarded as a care-receiver stable on the robot arms. By applying Newton-Euler equations of motion, dynamic model of the object is obtained. In this model, for describing interaction behavior between object and robot arms in the normal direction, a viscoelastic model is employed to represent the normal forces. Considering existence of friction between object and robot arms, LuGre dynamic model is applied to describe the friction. Based on the obtained model, an optimal regulator is designed to control the holding motion of two-cooperative-arm robot. In order to verify the effectiveness of the proposed method, simulation results are shown.

Cooperative game analysis of a supply chain with one risk-neutral supplier and two risk-averse retailers

Directory of Open Access Journals (Sweden)

Changwen Li

2014-09-01

Full Text Available Purpose: This paper considers a two-echelon supply chain composed of one risk-neutral supplier and two risk-averse retailers. The retailers obtain production from the supplier and sell them to the market. Based on the cooperative game theory, the paper studies the appropriate profit allocation of the supply chain when all the players cooperate with each other, where the two retailers face a price-sensitive stochastic demand. The two retailers can either determine their retail prices independently, or decide whether or not to cooperate with each other. Design/methodology/approach: To allocate the system-wide profit among upstream risk-neutral suppliers and two risk-averse downstream retailers, this paper constructed a cooperative game model, considered as the supermodularity of the characteristic function and the Shapley value of the game. Findings and Originality/value: By analyzing the construction’s cooperative game model, the results show that the profit of the whole supply chain is the highest in the grand coalition structure. This paper also shows that the core of our cooperative game is nonempty, and has the supermodularity property. Based on this, we have computed the Shapley value-based profit allocation for the whole supply chain in a fair manner. Originality/value: Although there are a lot of literature examined risk aversion in a supply chain, but they did not consider using cooperative game to study this problem. This the first study is in the context of a supply chain with risk aversion problem.

Variation in cooperative behaviour within a single city.

Directory of Open Access Journals (Sweden)

Daniel Nettle

Full Text Available Human cooperative behaviour, as assayed by decisions in experimental economic dilemmas such as the Dictator Game, is variable across human populations. Within-population variation has been less well studied, especially within industrial societies. Moreover, little is known about the extent to which community-level variation in Dictator Game behaviour relates to community-level variation in real-world social behaviour. We chose two neighbourhoods of the city of Newcastle upon Tyne that were similar in most regards, but at opposite ends of the spectrum in terms of level of socioeconomic deprivation. We administered Dictator Games to randomly-selected residents, and also gathered a large number of more naturalistic measures of cooperativeness. There were dramatic differences in Dictator Game behaviour between the two neighbourhoods, with the mean allocation to the other player close to half the stake in the affluent neighbourhood, and close to one tenth of the stake in the deprived neighbourhood. Moreover, the deprived neighbourhood was also characterised by lower self-reported social capital, higher frequencies of crime and antisocial behaviour, a higher frequency of littering, and less willingness to take part in a survey or return a lost letter. On the other hand, there were no differences between the neighbourhoods in terms of the probability of helping a person who dropped an object, needed directions to a hospital, or needed to make change for a coin, and people on the streets were less likely to be alone in the deprived neighbourhood than the affluent one. We conclude that there can be dramatic local differences in cooperative behaviour within the same city, and that these need further theoretical explanation.

Russian-Chinese Humanitarian Cooperation in 1990-s

Directory of Open Access Journals (Sweden)

E I Ganshina

2015-12-01

Full Text Available The article is devoted to Russian-Chinese humanitarian cooperation in the 90-ies of XX century. The author emphasizes the special importance of humanitarian cooperation between Russia and China for the promotion of national interests and the expansion of Russia's presence in China after the collapse of the USSR, as well as creating a positive image of the Russian state in China by applying the mechanism of “soft power”. The author notes that the 90-ies of XX century were the starting point of cooperation between Russia and China in the humanitarian sphere, it laid the legal foundation of Russian-Chinese humanitarian cooperation, moreover, the main directions and priorities of cooperation between the two countries in the humanitarian field have been identified. However, the author stresses that the practical realization of the objectives of the signed intergovernmental documents was carried out in an insufficiently wide format. And the main reason is the deep socio-economic crisis, which Russia had faced after the collapse of the Soviet Union, and, as a consequence, the lack of funding for joint Russian-Chinese projects in the humanitarian field.

TWO-LEVEL HIERARCHICAL COORDINATION QUEUING METHOD FOR TELECOMMUNICATION NETWORK NODES

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M. V. Semenyaka

2014-07-01

Full Text Available The paper presents hierarchical coordination queuing method. Within the proposed method a queuing problem has been reduced to optimization problem solving that was presented as two-level hierarchical structure. The required distribution of flows and bandwidth allocation was calculated at the first level independently for each macro-queue; at the second level solutions obtained on lower level for each queue were coordinated in order to prevent probable network link overload. The method of goal coordination has been determined for multilevel structure managing, which makes it possible to define the order for consideration of queue cooperation restrictions and calculation tasks distribution between levels of hierarchy. Decisions coordination was performed by the method of Lagrange multipliers. The study of method convergence has been carried out by analytical modeling.

Role of spontaneous emission through operating transition in probe-field spectroscopy of two-level systems

Energy Technology Data Exchange (ETDEWEB)

Saprykin, E. G. [Russian Academy of Sciences, Institute of Automation and Electrometry, Siberian Branch (Russian Federation); Chernenko, A. A., E-mail: chernen@isp.nsc.ru [Russian Academy of Sciences, Rzhanov Institute of Semiconductor Physics, Siberian Branch (Russian Federation); Shalagin, A. M. [Russian Academy of Sciences, Institute of Automation and Electrometry, Siberian Branch (Russian Federation)

2016-08-15

Analytical and numerical investigations are carried out of the effect of spontaneous decay through operating transition on the shape of a resonance in the work of a probe field under a strong field applied to the transition. A narrow nonlinear resonance arising on transitions with long-living lower level in the work of a probe field can manifest itself in the form of a traditional minimum and a peak as a function of the first Einstein coefficient for the operating transition. The transformation of the resonance from a minimum to a peak is attributed to the specific character of relaxation of lower-level population beatings on a closed or almost closed transition (the decay of the upper level occurs completely or almost completely through the operating transition).

Deterministic Mean-Field Ensemble Kalman Filtering

KAUST Repository

Law, Kody

2016-05-03

The proof of convergence of the standard ensemble Kalman filter (EnKF) from Le Gland, Monbet, and Tran [Large sample asymptotics for the ensemble Kalman filter, in The Oxford Handbook of Nonlinear Filtering, Oxford University Press, Oxford, UK, 2011, pp. 598--631] is extended to non-Gaussian state-space models. A density-based deterministic approximation of the mean-field limit EnKF (DMFEnKF) is proposed, consisting of a PDE solver and a quadrature rule. Given a certain minimal order of convergence k between the two, this extends to the deterministic filter approximation, which is therefore asymptotically superior to standard EnKF for dimension d<2k. The fidelity of approximation of the true distribution is also established using an extension of the total variation metric to random measures. This is limited by a Gaussian bias term arising from nonlinearity/non-Gaussianity of the model, which arises in both deterministic and standard EnKF. Numerical results support and extend the theory.

Deterministic Mean-Field Ensemble Kalman Filtering

KAUST Repository

Law, Kody; Tembine, Hamidou; Tempone, Raul

2016-01-01

The proof of convergence of the standard ensemble Kalman filter (EnKF) from Le Gland, Monbet, and Tran [Large sample asymptotics for the ensemble Kalman filter, in The Oxford Handbook of Nonlinear Filtering, Oxford University Press, Oxford, UK, 2011, pp. 598--631] is extended to non-Gaussian state-space models. A density-based deterministic approximation of the mean-field limit EnKF (DMFEnKF) is proposed, consisting of a PDE solver and a quadrature rule. Given a certain minimal order of convergence k between the two, this extends to the deterministic filter approximation, which is therefore asymptotically superior to standard EnKF for dimension d<2k. The fidelity of approximation of the true distribution is also established using an extension of the total variation metric to random measures. This is limited by a Gaussian bias term arising from nonlinearity/non-Gaussianity of the model, which arises in both deterministic and standard EnKF. Numerical results support and extend the theory.

Status of Korean nuclear industry and Romania-Korea cooperation in the field of nuclear power

International Nuclear Information System (INIS)

Lee, Myung Key

2005-01-01

The Kyoto Protocol on climate change has urged the world to explore ways of cutting down the greenhouse emissions, and it also boosted a number of nuclear power projects that is so-called the renaissance of nuclear power. Nuclear power has proven to be the cleanest energy source and one of the cheapest types of energies, compared with other energy sources. Korea began developing its nuclear power projects from the early 1970's. Since the first nuclear power plant Kori Unit 1, started commercial operation in 1978, Korea has continuously promoted the development of nuclear power projects, and today it operates 20 nuclear power units (17,716 MW), including 4 units of CANDU plants. Korea ranked No. 6 in the world in terms of installed capacity of nuclear power plants, and 40% of its domestic electricity generation comes from nuclear power plants. The average plant capacity factor was 95.5% in 2005, which is about 16% than the world average of around 79%. All the Korean nuclear power projects are led and implemented by Korea Hydro and Nuclear Power Co. (KHNP) which is the sole state-owned nuclear power project company spun off from Korea Electric Power Corporation (KEPCO) in 2001 as part of the government's program for electric industry restructuring. The cooperation between Romania and Korea in the nuclear power field began in March 2001. At industrial level a technical agreement between the Romanian Company Nuclearelectrica S.A. (SNN) and KHNP was signed in July 2003 for cooperation in Cernavoda NPP projects. The joint development of the Cernavoda NPP unit 3 was one of the major topics. Heavy water produced by Romanian Heavy Water plant at Drobeta Turnu Severin was supplied to KHNP (16 tones in 2001 and another 16 tones in 2004). The feasibility study for units 3 and 4 is being performed in two phases under leadership of SNN in cooperation with KHNP, AECL, ANSALDO and Deloitte and Touche as a financial advisor in Phase 2. It is expected that the appropriate securities

The role of autoshaping in cooperative two-player games between starlings.

Science.gov (United States)

Reboreda, J C; Kacelnik, A

1993-07-01

We report a study of the behavior of starlings in laboratory situations inspired by the "prisoner's dilemma." Our purpose is to investigate some possible mechanisms for the maintenance of cooperation by reciprocity and to investigate the process of autoshaping at a trial-by-trial level. In Experiment 1, pairs of starlings housed in adjacent cages played a discrete-trial "game" in which food could be obtained only by "cooperation." In this game, pecking at a response key eliminated the opportunity to obtain food but produced food for the partner. If neither bird pecked, neither had the opportunity to obtain food in that trial. Some level of cooperation persisted for several sessions whether the birds had been pretrained for a high or low probability of pecking at the key. The probability of a cooperative response was higher after trials in which the partner responded (and a reward was obtained) than after trials in which neither bird responded (and no reward was obtained), but the probability of a response was even higher after trials in which the same bird had responded, even though no reward was obtained by the actor in these trials. This behavior did not require visual presence of another player, because similar results were obtained in Experiment 2 (a replicate of Experiment 1 in which the members of the pair could not see each other) and in Experiment 3, a game in which each starling played with a computer responding with "tit for tat." Using an omission schedule, in which food was given in all trials in which the bird did not peck, Experiment 4 showed that pecking could be maintained by autoshaping. In this experiment, overall probability of pecking decreased with experience, due to a drop in the tendency to peck in consecutive trials. The probability of pecking in trials following a reinforced trial did not decrease with experience. An implementation of the Rescorla-Wagner model for this situation was capable of reproducing molar, but not molecular, aspects

Momentum and density dependence of the nuclear mean field

International Nuclear Information System (INIS)

Behera, B.; Routray, T.R.

1999-01-01

The purpose of this is to analyse the momentum, density and temperature dependence of the mean field in nuclear matter derived from finite range effective interactions and to examine the influence of the functional form of the interaction on the high momentum behaviour of the mean field. Emphasis will be given to use very simple parametrizations of the effective interaction with a minimum number of adjustable parameters and yet capable of giving a good description of the mean field in nuclear matter over a wide range of momentum, density and temperature. As an application of the calculated equation of state of nuclear matter, phase transitions to quark-gluon plasma is studied where the quark phase is described by a zeroth order bag model equation of state

Fact or fiction? An empirical analysis of cooperation between mass sport providers at the local level

NARCIS (Netherlands)

Steven Vos; Jeroen Scheerder

2014-01-01

This paper explores inter-organisational relationships, in terms of cooperation, between three main types of sport providers at the local level: voluntary sport clubs, for-profit fitness and health clubs, and local sports authorities. Both withinand cross-sector cooperation are analysed and related

Two-dimensional electron states bound to an off-plane donor in a magnetic field

International Nuclear Information System (INIS)

Bruno-Alfonso, A; Candido, L; Hai, G-Q

2010-01-01

The states of an electron confined in a two-dimensional (2D) plane and bound to an off-plane donor impurity center, in the presence of a magnetic field, are investigated. The energy levels of the ground state and the first three excited states are calculated variationally. The binding energy and the mean orbital radius of these states are obtained as a function of the donor center position and the magnetic field strength. The limiting cases are discussed for an in-plane donor impurity (i.e. a 2D hydrogen atom) as well as for the donor center far away from the 2D plane in strong magnetic fields, which corresponds to a 2D harmonic oscillator.

Functional differential equation approach to the large N expansion and mean field perturbation theory

International Nuclear Information System (INIS)

Bender, C.M.; Cooper, F.

1985-01-01

An apparent difference between formulating mean field perturbation theory for lambdaphi 4 field theory via path integrals or via functional differential equations when there are external sources present is shown not to exist when mean field theory is considered as the N = 1 limit of the 0(N)lambdaphi 4 field theory. A simply method is given for determining the 1/N expansion for the Green's functions in the presence of external sources by directly solving the functional differential equations order by order in 1/N. The 1/N expansion for the effective action GAMMA(phi,chi) is obtained by directly integrating the functional differential equations for the fields phi and chi (equivalent1/2lambda/Nphi/sub α/phi/sup α/-μ 2 ) in the presence of two external sources j = -deltaGAMMA/deltaphi, S = -deltaGAMMA/deltachi

Mean field with corrections in lattice gauge theory

International Nuclear Information System (INIS)

Flyvbjerg, H.; Zuber, J.B.; Lautrup, B.

1981-12-01

A systematic expansion of the path integral for lattice gauge theory is performed around the mean field solution. In this letter the authors present the results for the pure gauge groups Z(2), SU(2) and SO(3). The agreement with Monte Carlo calculations is excellent. For the discrete group the calculation is performed with and without gauge fixing, whereas for the continuous groups gauge fixing is mandatory. In the case of SU(2) the absence of a phase transition is correctly signalled by mean field theory. (Auth.)

Configuration mixing of mean-field states

International Nuclear Information System (INIS)

Bender, M; Heenen, P-H

2005-01-01

Starting from self-consistent mean-field models, we discuss how to include correlations from fluctuations in collective degrees of freedom through symmetry restoration and configuration mixing, which give access to ground-state correlations and collective excitations. As an example for the method, we discuss the spectroscopy of neutron-deficient Pb isotopes

Identifying a cooperative control mechanism between an applied field and the environment of open quantum systems

Science.gov (United States)

Gao, Fang; Rey-de-Castro, Roberto; Wang, Yaoxiong; Rabitz, Herschel; Shuang, Feng

2016-05-01

Many systems under control with an applied field also interact with the surrounding environment. Understanding the control mechanisms has remained a challenge, especially the role played by the interaction between the field and the environment. In order to address this need, here we expand the scope of the Hamiltonian-encoding and observable-decoding (HE-OD) technique. HE-OD was originally introduced as a theoretical and experimental tool for revealing the mechanism induced by control fields in closed quantum systems. The results of open-system HE-OD analysis presented here provide quantitative mechanistic insights into the roles played by a Markovian environment. Two model open quantum systems are considered for illustration. In these systems, transitions are induced by either an applied field linked to a dipole operator or Lindblad operators coupled to the system. For modest control yields, the HE-OD results clearly show distinct cooperation between the dynamics induced by the optimal field and the environment. Although the HE-OD methodology introduced here is considered in simulations, it has an analogous direct experimental formulation, which we suggest may be applied to open systems in the laboratory to reveal mechanistic insights.

Toxicity evaluation of natural samples from the vicinity of rice fields using two trophic levels.

Science.gov (United States)

Marques, Catarina R; Pereira, Ruth; Gonçalves, Fernando

2011-09-01

An ecotoxicological screening of environmental samples collected in the vicinity of rice fields followed a combination of physical and chemical measurements and chronic bioassays with two freshwater trophic levels (microalgae: Pseudokirchneriella subcapitata and Chlorella vulgaris; daphnids: Daphnia longispina and Daphnia magna). As so, water and sediment/soil elutriate samples were obtained from three sites: (1) in a canal reach crossing a protected wetland upstream, (2) in a canal reach surrounded by rice fields and (3) in a rice paddy. The sampling was performed before and during the rice culture. During the rice cropping, the whole system quality decreased comparatively to the situation before that period (e.g. nutrient overload, the presence of pesticides in elutriates from sites L2 and L3). This was reinforced by a significant inhibition of both microalgae growth, especially under elutriates. Contrary, the life-history traits of daphnids were significantly stimulated with increasing concentrations of water and elutriates, for both sampling periods.

Resource Management and Prevention of Moral Harassment: The Cases of Two Agricultural Cooperatives of Paraná

Directory of Open Access Journals (Sweden)

Aline Alves Storti

2017-05-01

Full Text Available The objective of this study was to identify and analyze how preventive work is done on issues related to moral harassment in two agricultural cooperatives in Paraná. The locus chosen for analysis was justified by the need for actions that curb harassment in organizations and by the peculiarity of the environment, in addition to the two cooperatives surveyed being large employers in their region. A qualitative case study approach was taken. Descriptive data was collected through document research and interviews with four managers of the two cooperatives. Findings revealed that both cooperatives analyzed have no records of moral harassment in the Regional Labor Court and use some prevention methods. In addition, statements by personnel management professionals presented some discrepancies with other professionals interviewed, which may be related to a lack of knowledge on the theme or to cultural aspects. The Green Cooperative presented more preventive methods to moral harassment than the Blue Cooperative, including a code of ethics, denunciations via e-mail, organization environment research, a denunciation box and harassment prevention training for future leaders. The Blue Cooperative uses formal channels of communication and employee dialogue, but nothing specifically directed towards situations of harassment, organization climate research, or a code of ethics. Areas of personnel management are suggested to invest more in communicating prevention actions with those involved, which encourages dialogue and the dissemination of knowledge on what harassment is and how to prevent it.

Mean field approximation versus exact treatment of collisions in few-body systems

International Nuclear Information System (INIS)

Lemm, J.; Weiguny, A.; Giraud, B.G.

1990-01-01

A variational principle for calculating matrix elements of the full resolvent operator for a many-body system is studied. Its mean field approximation results in non-linear equations of Hartree (-Fock) type, with initial and final channel wave functions as driving terms. The mean field equations will in general have many solutions whereas the exact problem being linear, has a unique solution. In a schematic model with separable forces the mean field equations are analytically soluble, and for the exact problem the resulting integral equations are solved numerically. Comparing exact and mean field results over a wide range of system parameters, the mean field approach proves to be a very reliable approximation, which is not plagued by the notorious problem of defining asymptotic channels in the time-dependent mean field method. (orig.)

Towards Efficient Wireless Body Area Network Using Two-Way Relay Cooperation.

Science.gov (United States)

Waheed, Maham; Ahmad, Rizwan; Ahmed, Waqas; Drieberg, Micheal; Alam, Muhammad Mahtab

2018-02-13

The fabrication of lightweight, ultra-thin, low power and intelligent body-borne sensors leads to novel advances in wireless body area networks (WBANs). Depending on the placement of the nodes, it is characterized as in/on body WBAN; thus, the channel is largely affected by body posture, clothing, muscle movement, body temperature and climatic conditions. The energy resources are limited and it is not feasible to replace the sensor's battery frequently. In order to keep the sensor in working condition, the channel resources should be reserved. The lifetime of the sensor is very crucial and it highly depends on transmission among sensor nodes and energy consumption. The reliability and energy efficiency in WBAN applications play a vital role. In this paper, the analytical expressions for energy efficiency (EE) and packet error rate (PER) are formulated for two-way relay cooperative communication. The results depict better reliability and efficiency compared to direct and one-way relay communication. The effective performance range of direct vs. cooperative communication is separated by a threshold distance. Based on EE calculations, an optimal packet size is observed that provides maximum efficiency over a certain link length. A smart and energy efficient system is articulated that utilizes all three communication modes, namely direct, one-way relay and two-way relay, as the direct link performs better for a certain range, but the cooperative communication gives better results for increased distance in terms of EE. The efficacy of the proposed hybrid scheme is also demonstrated over a practical quasi-static channel. Furthermore, link length extension and diversity is achieved by joint network-channel (JNC) coding the cooperative link.

Towards Efficient Wireless Body Area Network Using Two-Way Relay Cooperation

Directory of Open Access Journals (Sweden)

Maham Waheed

2018-02-01

Full Text Available The fabrication of lightweight, ultra-thin, low power and intelligent body-borne sensors leads to novel advances in wireless body area networks (WBANs. Depending on the placement of the nodes, it is characterized as in/on body WBAN; thus, the channel is largely affected by body posture, clothing, muscle movement, body temperature and climatic conditions. The energy resources are limited and it is not feasible to replace the sensor’s battery frequently. In order to keep the sensor in working condition, the channel resources should be reserved. The lifetime of the sensor is very crucial and it highly depends on transmission among sensor nodes and energy consumption. The reliability and energy efficiency in WBAN applications play a vital role. In this paper, the analytical expressions for energy efficiency (EE and packet error rate (PER are formulated for two-way relay cooperative communication. The results depict better reliability and efficiency compared to direct and one-way relay communication. The effective performance range of direct vs. cooperative communication is separated by a threshold distance. Based on EE calculations, an optimal packet size is observed that provides maximum efficiency over a certain link length. A smart and energy efficient system is articulated that utilizes all three communication modes, namely direct, one-way relay and two-way relay, as the direct link performs better for a certain range, but the cooperative communication gives better results for increased distance in terms of EE. The efficacy of the proposed hybrid scheme is also demonstrated over a practical quasi-static channel. Furthermore, link length extension and diversity is achieved by joint network-channel (JNC coding the cooperative link.

Precise mean sea level measurements using the Global Positioning System

Science.gov (United States)

Kelecy, Thomas M.; Born, George H.; Parke, Michael E.; Rocken, Christian

1994-01-01

This paper describes the results of a sea level measurement test conducted off La Jolla, California, in November of 1991. The purpose of this test was to determine accurate sea level measurements using a Global Positioning System (GPS) equipped buoy. These measurements were intended to be used as the sea level component for calibration of the ERS 1 satellite altimeter. Measurements were collected on November 25 and 28 when the ERS 1 satellite overflew the calibration area. Two different types of buoys were used. A waverider design was used on November 25 and a spar design on November 28. This provided the opportunity to examine how dynamic effects of the measurement platform might affect the sea level accuracy. The two buoys were deployed at locations approximately 1.2 km apart and about 15 km west of a reference GPS receiver located on the rooftop of the Institute of Geophysics and Planetary Physics at the Scripps Institute of Oceanography. GPS solutions were computed for 45 minutes on each day and used to produce two sea level time series. An estimate of the mean sea level at both locations was computed by subtracting tide gage data collected at the Scripps Pier from the GPS-determined sea level measurements and then filtering out the high-frequency components due to waves and buoy dynamics. In both cases the GPS estimate differed from Rapp's mean altimetric surface by 0.06 m. Thus, the gradient in the GPS measurements matched the gradient in Rapp's surface. These results suggest that accurate sea level can be determined using GPS on widely differing platforms as long as care is taken to determine the height of the GPS antenna phase center above water level. Application areas include measurement of absolute sea level, of temporal variations in sea level, and of sea level gradients (dominantly the geoid). Specific applications would include ocean altimeter calibration, monitoring of sea level in remote regions, and regional experiments requiring spatial and

Weakly coupled mean-field game systems

KAUST Repository

Gomes, Diogo A.

2016-07-14

Here, we prove the existence of solutions to first-order mean-field games (MFGs) arising in optimal switching. First, we use the penalization method to construct approximate solutions. Then, we prove uniform estimates for the penalized problem. Finally, by a limiting procedure, we obtain solutions to the MFG problem. © 2016 Elsevier Ltd

Differentiated-effect shims for medium field levels and saturation

International Nuclear Information System (INIS)

Richie, A.

1976-01-01

The arrangement of shims on the upstream and downstream ends of magnets may be based on the independent effects of variations in the geometric length and degree of saturation at the edges of the poles. This technique can be used to match the bending strength of an accelerator's magnets at two field levels (medium fields and maximum fields) and thus save special procedures (mixing the laminations, local compensation for errors by arranging the magnets in the appropriate order) and special devices (for instance, correcting dipoles) solely for correcting bending strengths at low field levels. (Auth.)

Level sets and extrema of random processes and fields

CERN Document Server

Azais, Jean-Marc

2009-01-01

A timely and comprehensive treatment of random field theory with applications across diverse areas of study Level Sets and Extrema of Random Processes and Fields discusses how to understand the properties of the level sets of paths as well as how to compute the probability distribution of its extremal values, which are two general classes of problems that arise in the study of random processes and fields and in related applications. This book provides a unified and accessible approach to these two topics and their relationship to classical theory and Gaussian processes and fields, and the most modern research findings are also discussed. The authors begin with an introduction to the basic concepts of stochastic processes, including a modern review of Gaussian fields and their classical inequalities. Subsequent chapters are devoted to Rice formulas, regularity properties, and recent results on the tails of the distribution of the maximum. Finally, applications of random fields to various areas of mathematics a...

Self-organization towards optimally interdependent networks by means of coevolution

International Nuclear Information System (INIS)

Wang, Zhen; Szolnoki, Attila; Perc, Matjaž

2014-01-01

Coevolution between strategy and network structure is established as a means to arrive at the optimal conditions needed to resolve social dilemmas. Yet recent research has highlighted that the interdependence between networks may be just as important as the structure of an individual network. We therefore introduce the coevolution of strategy and network interdependence to see whether this can give rise to elevated levels of cooperation in the prisoner's dilemma game. We show that the interdependence between networks self-organizes so as to yield optimal conditions for the evolution of cooperation. Even under extremely adverse conditions, cooperators can prevail where on isolated networks they would perish. This is due to the spontaneous emergence of a two-class society, with only the upper class being allowed to control and take advantage of the interdependence. Spatial patterns reveal that cooperators, once arriving at the upper class, are much more competent than defectors in sustaining compact clusters of followers. Indeed, the asymmetric exploitation of interdependence confers to them a strong evolutionary advantage that may resolve even the toughest of social dilemmas. (paper)

Identifying meaning and perceived level of satisfaction within the context of work.

Science.gov (United States)

Brown, Angie; Kitchell, Molly; O'Neill, Tiffany; Lockliear, Jennifer; Vosler, Alyson; Kubek, Dayna; Dale, Lucinda

2001-01-01

OBJECTIVE: The primary objectives of this study were to identify sources of meaning for individuals within the context of a work environment, and to compare varied sources of meaning for individuals with high and low work satisfaction levels. METHOD: Participants were chosen based on satisfaction levels in employment, full-time employment status within an organization for at least one year, and diversity in the work setting. Data were gathered through a series of interviews and observations of the participants' workplaces. A comparative analysis of transcribed interviews was conducted by the researchers and with an expert occupational therapy faculty panel. From these analyses, the researchers developed work narratives for a mechanical engineer, a high school teacher, an employee of mechanical services, and a career service counselor. RESULTS: Emerging themes from the work narratives indicated that the various meanings employees found in work had an effect on their perceived levels of job satisfaction. Participants conveyed that organization identification, financial benefits, independent decision-making, reciprocal respect, opportunities for creativity, and maintaining significant relationships outside of work enhanced meaning and satisfaction. CONCLUSIONS: The worker role is a significant source of an individual's identity, meaning, and satisfaction in life. Professionals in various fields can work with employers to develop meaningful work environments for increased job satisfaction, greater motivation for work, increased productivity, and decreased employee turnover.

Mean-field theory and self-consistent dynamo modeling

International Nuclear Information System (INIS)

Yoshizawa, Akira; Yokoi, Nobumitsu

2001-12-01

Mean-field theory of dynamo is discussed with emphasis on the statistical formulation of turbulence effects on the magnetohydrodynamic equations and the construction of a self-consistent dynamo model. The dynamo mechanism is sought in the combination of the turbulent residual-helicity and cross-helicity effects. On the basis of this mechanism, discussions are made on the generation of planetary magnetic fields such as geomagnetic field and sunspots and on the occurrence of flow by magnetic fields in planetary and fusion phenomena. (author)

Scandinavian Cooperative Advantage

DEFF Research Database (Denmark)

Strand, Robert; Freeman, R. Edward

2015-01-01

. We conclude by endorsing the expression “Scandinavian cooperative advantage” in an effort to draw attention to the Scandinavian context and encourage the field of strategic management to shift its focus from achieving a competitive advantage toward achieving a cooperative advantage....

A study on the establishment of nuclear cooperative relations and future direction between Korea and Egypt

Energy Technology Data Exchange (ETDEWEB)

Yang, M. H.; Kim, H. S.; Kim, H. J.; Yun, S. W.; Ko, H. S

2000-10-01

This study was carried out in order to review the cooperation with Egypt and establish and activate the cooperative relations with Egypt. Recent policy trends in the use and development of nuclear energy in Egypt, were investigated including introduction of nuclear power plant, and cooperative relations between two nations were also established under the implementation of the project. It was agreed through exchanges of visits of nuclear cooperation delegation; 1) exchange of visits of cooperation delegation, 2) invitation of egypt experts to policy seminar 3) cooperation between relevant nuclear related organizations of two countries, 4) future cooperation fields and directions between two countries. It is recommended that cooperation with Egypt be implemented systematically through the long term based on national basic cooperation directions and integrated strategies.

A study on the establishment of nuclear cooperative relations and future direction between Korea and Egypt

International Nuclear Information System (INIS)

Yang, M. H.; Kim, H. S.; Kim, H. J.; Yun, S. W.; Ko, H. S.

2000-10-01

This study was carried out in order to review the cooperation with Egypt and establish and activate the cooperative relations with Egypt. Recent policy trends in the use and development of nuclear energy in Egypt, were investigated including introduction of nuclear power plant, and cooperative relations between two nations were also established under the implementation of the project. It was agreed through exchanges of visits of nuclear cooperation delegation; 1) exchange of visits of cooperation delegation, 2) invitation of egypt experts to policy seminar 3) cooperation between relevant nuclear related organizations of two countries, 4) future cooperation fields and directions between two countries. It is recommended that cooperation with Egypt be implemented systematically through the long term based on national basic cooperation directions and integrated strategies

Thou should not know too much. When lack of information promotes co-operative behaviour. The case of oil-fields in Wyoming, Oklahoma and Texas

Energy Technology Data Exchange (ETDEWEB)

Hassler, B

1998-12-31

Proper assumptions of information levels are of vital importance in all kinds of analysis of interdependent decision-making. In most cases the rule is; the more information the better. In this paper, however, it is shown that such is not always the case. Lack of information can enhance resource utilisation of resources, when the problem of co-operation is of a Prisoner`s dilemma type, and when iteration of the interaction game is unlikely. The case of oil-fields in the United States has been chosen as an empirical example of the latter. Optimal drilling procedures tend to be chosen more often the less the drillers know about the resource characteristics. This outcome is explained by the structure of the decision-making problem, where low levels of information render it advantageous to choose co-operative strategies 16 refs, 4 figs

Thou should not know too much. When lack of information promotes co-operative behaviour. The case of oil-fields in Wyoming, Oklahoma and Texas

Energy Technology Data Exchange (ETDEWEB)

Hassler, B.

1997-12-31

Proper assumptions of information levels are of vital importance in all kinds of analysis of interdependent decision-making. In most cases the rule is; the more information the better. In this paper, however, it is shown that such is not always the case. Lack of information can enhance resource utilisation of resources, when the problem of co-operation is of a Prisoner`s dilemma type, and when iteration of the interaction game is unlikely. The case of oil-fields in the United States has been chosen as an empirical example of the latter. Optimal drilling procedures tend to be chosen more often the less the drillers know about the resource characteristics. This outcome is explained by the structure of the decision-making problem, where low levels of information render it advantageous to choose co-operative strategies 16 refs, 4 figs

A mean field theory of coded CDMA systems

International Nuclear Information System (INIS)

Yano, Toru; Tanaka, Toshiyuki; Saad, David

2008-01-01

We present a mean field theory of code-division multiple-access (CDMA) systems with error-control coding. On the basis of the relation between the free energy and mutual information, we obtain an analytical expression of the maximum spectral efficiency of the coded CDMA system, from which a mean-field description of the coded CDMA system is provided in terms of a bank of scalar Gaussian channels whose variances in general vary at different code symbol positions. Regular low-density parity-check (LDPC)-coded CDMA systems are also discussed as an example of the coded CDMA systems

A mean field theory of coded CDMA systems

Energy Technology Data Exchange (ETDEWEB)

Yano, Toru [Graduate School of Science and Technology, Keio University, Hiyoshi, Kohoku-ku, Yokohama-shi, Kanagawa 223-8522 (Japan); Tanaka, Toshiyuki [Graduate School of Informatics, Kyoto University, Yoshida Hon-machi, Sakyo-ku, Kyoto-shi, Kyoto 606-8501 (Japan); Saad, David [Neural Computing Research Group, Aston University, Birmingham B4 7ET (United Kingdom)], E-mail: yano@thx.appi.keio.ac.jp

2008-08-15

We present a mean field theory of code-division multiple-access (CDMA) systems with error-control coding. On the basis of the relation between the free energy and mutual information, we obtain an analytical expression of the maximum spectral efficiency of the coded CDMA system, from which a mean-field description of the coded CDMA system is provided in terms of a bank of scalar Gaussian channels whose variances in general vary at different code symbol positions. Regular low-density parity-check (LDPC)-coded CDMA systems are also discussed as an example of the coded CDMA systems.

Cooperation of CMEA member states in the field of the manufacture and use of stable isotopes and compounds thus labelled

International Nuclear Information System (INIS)

Ertel, G.; Ewald, G.

1977-01-01

The contribution presents a survey of scientific-technical cooperation of CMEA member states in the field of stable isotopes, it deals with the specialization of stable isotope production and compounds thus labelled, and gives the prospects for further development of this cooperation. (HK) [de

A simplified BBGKY hierarchy for correlated fermions from a stochastic mean-field approach

International Nuclear Information System (INIS)

Lacroix, Denis; Tanimura, Yusuke; Ayik, Sakir; Yilmaz, Bulent

2016-01-01

The stochastic mean-field (SMF) approach allows to treat correlations beyond mean-field using a set of independent mean-field trajectories with appropriate choice of fluctuating initial conditions. We show here that this approach is equivalent to a simplified version of the Bogolyubov-Born-Green-Kirkwood-Yvon (BBGKY) hierarchy between one-, two-,.., N -body degrees of freedom. In this simplified version, one-body degrees of freedom are coupled to fluctuations to all orders while retaining only specific terms of the general BBGKY hierarchy. The use of the simplified BBGKY is illustrated with the Lipkin-Meshkov-Glick (LMG) model. We show that a truncated version of this hierarchy can be useful, as an alternative to the SMF, especially in the weak coupling regime to get physical insight in the effect beyond mean-field. In particular, it leads to approximate analytical expressions for the quantum fluctuations both in the weak and strong coupling regime. In the strong coupling regime, it can only be used for short time evolution. In that case, it gives information on the evolution time-scale close to a saddle point associated to a quantum phase-transition. For long time evolution and strong coupling, we observed that the simplified BBGKY hierarchy cannot be truncated and only the full SMF with initial sampling leads to reasonable results. (orig.)

Conformal field theory with two kinds of Bosonic fields and two linear dilatons

International Nuclear Information System (INIS)

Kamani, Davoud

2010-01-01

We consider a two-dimensional conformal field theory which contains two kinds of the bosonic degrees of freedom. Two linear dilaton fields enable to study a more general case. Various properties of the model such as OPEs, central charge, conformal properties of the fields and associated algebras will be studied. (author)

Phase diagram of the mean field model of simplicial gravity

International Nuclear Information System (INIS)

Bialas, P.; Burda, Z.; Johnston, D.

1999-01-01

We discuss the phase diagram of the balls in boxes model, with a varying number of boxes. The model can be regarded as a mean-field model of simplicial gravity. We analyse in detail the case of weights of the form p(q) = q -β , which correspond to the measure term introduced in the simplicial quantum gravity simulations. The system has two phases: elongated (fluid) and crumpled. For β ε (2, ∞) the transition between these two phases is first-order, while for β ε (1, 2) it is continuous. The transition becomes softer when β approaches unity and eventually disappears at β = 1. We then generalise the discussion to an arbitrary set of weights. Finally, we show that if one introduces an additional kinematic bound on the average density of balls per box then a new condensed phase appears in the phase diagram. It bears some similarity to the crinkled phase of simplicial gravity discussed recently in models of gravity interacting with matter fields

CONDITIONS OF COOPERATION BETWEEN COMPANIES AND NGOs IN THE FIELD OF CORPORATE SOCIAL RESPONSIBILITY ACTIVITIES: THE POLISH CASES

Directory of Open Access Journals (Sweden)

Rafał Drewniak

2015-12-01

Full Text Available Corporate social responsibility (CSR is becoming an increasingly popular area of activity of companies which are interested in not only the managers or owners, but also customers, suppliers, NGOs, administrative and other stakeholders groups. The analysis aim is to present CSR initiatives as part of deliberate strategy of the company, which is one of the key sources of competitive advantage in the market. The findings concern the scope of cooperation between companies and NGOs in the field of socially responsible activities. The analysis indicates that the expected form of cooperation of NGOs with small businesses is to provide financial assistance to social organizations. However, in the case of medium-sized enterprises, these expectations also apply to material support. Moreover, in the case of medium-sized enterprises a key determinant of cooperation with social organization is realization of the social objective, while small businesses are more guided by "goodness of the heart". Considerations based on the identification of scope of CSR, are pointing to the key aspects of this activity to the company, the environment and customers. Discussions were extended to the characteristics of the benefits, barriers and forms of the cooperation, as well as, there were presented the results of research in the field of forms and determinants of such cooperation. Considerations are based on secondary sources, from national and international journals, books, magazines and specialist reports.

Designing Leadership models in a Three Level Unlimited Supply Chain: Non-Cooperative Game Theory Approach

Directory of Open Access Journals (Sweden)

Ahmad Jaafarnehad

2015-09-01

Full Text Available The role and importance of supply chain management, has faced with many challenges and problems. Although a comprehensive model of supply chain issues, has not been explained, we have to indicate that issues such as reviewing the theoretical foundations of information systems, marketing, financial management, logistical and organizational relations have been considered by many researchers. The objective of supply chain management is to improve various activities and components to increase overall supply chain system benefits. In order to achieve the overall objectives, many contradictions may occur between the components and different levels of supply chain and the contradictions that these disorders over time, result in decreased strength and competitiveness of the supply chain. Such conflicts, like marketing costs (advertising, pricing and inventory can occur during the supply chain life cycle. A Game Theory approach with respect to property is the appropriate tool for collaboration in the supply chain. This tool is used for collaborative making in any kind of supply chain such as cooperative supply chain and non-cooperative supply chain. In the present study and assuming a lack of cooperation between different levels of a supply chain, a dynamic game with complete information has been generated. In addition identifying appropriate leaders of various levels of the supply chain is considered. Non-Cooperative dynamic game mode (Stackelberg Game, for each of the three levels of supply chain including retailers, suppliers and manufacturers are modeled. Depending on the bargaining power and its position in the market, any level of supply chain can make a leader of the following rule. In the present study, the equilibrium model to play Stackelberg game may be led by a leader or leading players and ultimately identifying and modeling the appropriate unlimited three level supply chain are determined.

Endogenous change: on cooperation and water availability in two ancient societies

Science.gov (United States)

Pande, S.; Ertsen, M.

2014-05-01

We propose and test the theory of endogenous change in societal institutions based on historical reconstructions of two ancient civilizations, the Indus and Hohokam, in two water-scarce basins, the Indus Basin in the Indian subcontinent and the lower Colorado Basin in the southwestern United States. In our reconstructions, institutions are approximated by the scale of "cooperation", be it in the form of the extent of trade, sophisticated irrigation networks, a central state or a loosely held state with a common cultural identity. We study changes in institutions brought about by changes in factors like rainfall, population density, and land-use-induced water resource availability, in a proximate manner. These factors either change naturally or are changed by humans; in either case we contend that the changes affect the stability of cooperative structures over time. We relate the quantitative dimensions of water access by ancient populations to the co-evolution of water access and the socioeconomic and sociopolitical organizations. In doing so, we do not claim that water manipulation was the single most significant factor in stimulating social development and complexity - this would be highly reductionist. Nonetheless, we provide a discussion with the aim to enhance our understanding of the complexity of coupled human-hydrological systems. We find that scarcity triggered more complex cooperative arrangements in both Indus and Hohokam societies.

Switching field of partially exchange-coupled particles

International Nuclear Information System (INIS)

Oliva, M.I.; Bertorello, H.R.; Bercoff, P.G.

2004-01-01

The magnetization reversal of partially exchange-coupled particles is studied in detail. The starting point is the observation of a complicated phenomenology in the irreversible susceptibility and FORC distribution functions of Ba hexaferrite samples obtained by means of different sintering conditions. Several peaks in the first-order reversal curve (FORC) distribution functions were identified and associated with clusters with different number of particles. The switching fields of these clusters were related to an effective anisotropy constant Keff that depends on the number of particles in the cluster. Keff is linked to the exchange-coupled volume between two neighboring particles and as a weighted mean between the anisotropy constants of the coupled and uncoupled volumes. By using the modified Brown's equation αex=0.322 is obtained.In order to interpret these results, the switching field of a two-particle system with partial exchange coupling is studied. It is assumed that the spins reorientation across the contact plane between the particles is like a Bloch wall. The energy of the system is written in terms of the fraction of volume affected by exchange coupling and the switching fields for both particles are calculated. At small interaction volume fraction each particle inverts its magnetization independently from the other. As the fraction of exchange-coupled volume increases, cooperative effects appear and the two particles invert their magnetization in a cooperative way.The proposed model allows to interpret for the first time the empirical factor αex in terms of physical arguments and also explain the details observed in the FORC distribution function

Scientific co-operation with IAEA in the field of marine radioactivity

International Nuclear Information System (INIS)

Bologa, S.Alexandru

1998-01-01

A short presentation of the communication presented in the Seminar on public information on peaceful uses of nuclear energy, NUCInfo'98, is given. It is emphasized the formation of RMRI specialists, its scientific co-operations with IAEA between 1986-1998 and participations in related scientific events. In the domain of specialists' formation there are mentioned the participation of members of the Institute in the training courses on marine radioecology, in the regional course on strategies and methodologies for applied marine radioactivity and environmental isotope studies for the Black Sea, and in the inter-regional course devoted to determination of radionuclides in environmental samples, held in 1986, 1994 and 1997, respectively. In the field of research co-operation there are presented the achievements obtained in the framework of five programs dealing mainly with monitoring of marine water, sediment and biota radioactivity in Romanian sector of Black Sea. Also reported are the participations and the contributions in the international scientific events devoted to marine environmental studies and the contributions to international databases

A cooperation model based on CVaR measure for a two-stage supply chain

Science.gov (United States)

Xu, Xinsheng; Meng, Zhiqing; Shen, Rui

2015-07-01

In this paper, we introduce a cooperation model (CM) for the two-stage supply chain consisting of a manufacturer and a retailer. In this model, it is supposed that the objective of the manufacturer is to maximise his/her profit while the objective of the retailer is to minimise his/her CVaR while controlling the risk originating from fluctuation in market demand. In reality, the manufacturer and the retailer would like to choose their own decisions as to wholesale price and order quantity to optimise their own objectives, resulting the fact that the expected decision of the manufacturer and that of the retailer may conflict with each other. Then, to achieve cooperation, the manufacturer and the retailer both need to give some concessions. The proposed model aims to coordinate the decisions of the manufacturer and the retailer, and balance the concessions of the two in their cooperation. We introduce an s* - optimal equilibrium solution in this model, which can decide the minimum concession that the manufacturer and the retailer need to give for their cooperation, and prove that the s* - optimal equilibrium solution can be obtained by solving a goal programming problem. Further, the case of different concessions made by the manufacturer and the retailer is also discussed. Numerical results show that the CM is efficient in dealing with the cooperations between the supplier and the retailer.

Ser derivation and power optimization of a two-way multirelay cooperative communication system