Application of Lie group analysis in geophysical fluid dynamics

CERN Document Server

Ibragimov, Ranis

2011-01-01

This is the first monograph dealing with the applications of the Lie group analysis to the modeling equations governing internal wave propagation in the deep ocean. A new approach to describe the nonlinear interactions of internal waves in the ocean is presented. While the central idea of the book is to investigate oceanic internal waves through the prism of Lie group analysis, it is also shown for the first time that internal wave beams, representing exact solutions to the equation of motion of stratified fluid, can be found by solving the given model as invariant solutions of nonlinear equat

Selection-driven extinction dynamics for group II introns in Enterobacteriales.

Directory of Open Access Journals (Sweden)

Sébastien Leclercq

Full Text Available Transposable elements (TEs are one of the major driving forces of genome evolution, raising the question of the long-term dynamics underlying their evolutionary success. Some TEs were proposed to evolve under a pattern of periodic extinctions-recolonizations, in which elements recurrently invade and quickly proliferate within their host genomes, then start to disappear until total extinction. Depending on the model, TE extinction is assumed to be driven by purifying selection against colonized host genomes (Sel-DE model or by saturation of host genomes (Sat-DE model. Bacterial group II introns are suspected to follow an extinction-recolonization model of evolution, but whether they follow Sel-DE or Sat-DE dynamics is not known. Our analysis of almost 200 group II intron copies from 90 sequenced Enterobacteriales genomes confirms their extinction-recolonization dynamics: patchy element distributions among genera and even among strains within genera, acquisition of new group II introns through plasmids or other mobile genetic elements, and evidence for recent proliferations in some genomes. Distributions of recent and past proliferations and of their respective homing sites further provide strong support for the Sel-DE model, suggesting that group II introns are deleterious to their hosts. Overall, our observations emphasize the critical impact of host properties on TE dynamics.

Dynamics of small groups of galaxies. I. Virialized groups

International Nuclear Information System (INIS)

Mamon, G.A.; New York Univ., NY)

1987-01-01

The dynamical evolution of small groups of galaxies from an initial virial equilibrium state is investigated by means of numerical simulations. The basic scheme is a gravitational N-body code in which galaxies and diffuse background are treated as single particles with both external parameters and internal structure; collisional and tidal stripping, dynamical friction, mergers, and orbital braking are taken into account. The results are presented in extensive tables and graphs and characterized in detail. Eight-galaxy groups with surface densities like those of compact groups (as defined by Hickson, 1982) are found to be unstable to rapid mergers after 1/30 to 1/8 Hubble time. The effects of dark-matter distribution (in galactic halos or in a common intergalactic background) are considered. 79 references

Seismological analysis of group pile foundation for reactor

International Nuclear Information System (INIS)

Wang Demin.

1984-01-01

In the seismic analysis for reactor foundation of nuclear power plant, the local raise of base mat is of great significance. Base on the study of static and dynamic stability as well as soil-structure interaction of group piles on stratified soil, this paper presents a method of seismic analysis for group piles of reactor foundation at abroad, and a case history is enclosed. (Author)

Three-dimensional finite element nonlinear dynamic analysis of pile groups for lateral transient and seismic excitations

International Nuclear Information System (INIS)

Maheshwari, B.K.; Truman, K.Z.; El Naggar, M.H.; Gould, P.L.

2004-01-01

The effects of material nonlinearity of soil and separation at the soil-pile interface on the dynamic behaviour of a single pile and pile groups are investigated. An advanced plasticity-based soil model, hierarchical single surface (HiSS), is incorporated in the finite element formulation. To simulate radiation effects, proper boundary conditions are used. The model and algorithm are verified with analytical results that are available for elastic and elastoplastic soil models. Analyses are performed for seismic excitation and for the load applied on the pile cap. For seismic analysis, both harmonic and transient excitations are considered. For loading on the pile cap, dynamic stiffness of the soil-pile system is derived and the effect of nonlinearity is investigated. The effects of spacing between piles are investigated, and it was found that the effect of soil nonlinearity on the seismic response is very much dependent on the frequency of excitation. For the loading on a pile cap, the nonlinearity increases the response for most of the frequencies of excitation while decreasing the dynamic stiffness of the soil-pile system. (author)

Supervision is also about Addressing the Group Dynamics

DEFF Research Database (Denmark)

Jensen, Lars Peter; Hansen, S.

2003-01-01

that many students are having difficulties with practical issues such as collaboration, communication, and project management. Most supervisors either ignore this demand, because they do not find it important or they find it frustrating, because they do not know, how to supervise group dynamics......An important aspect of the problem based and project organized study at Aalborg University is the supervision of the project groups. At the basic education (first year) it is stated in the curriculum that part of the supervisors' job is to deal with group dynamics. This is due to the experience...... as well as at Aalborg University. The first visible result has been participating supervisors telling us that the course has inspired them to try supervising group dynamics in the future. This paper will explore some aspects of supervising group dynamics as well as, how to develop the Aalborg model...

Determination of arterial input function in dynamic susceptibility contrast MRI using group independent component analysis technique

International Nuclear Information System (INIS)

Chen, S.; Liu, H.-L.; Yang Yihong; Hsu, Y.-Y.; Chuang, K.-S.

2006-01-01

Quantification of cerebral blood flow (CBF) with dynamic susceptibility contrast (DSC) magnetic resonance imaging (MRI) requires the determination of the arterial input function (AIF). The segmentation of surrounding tissue by manual selection is error-prone due to the partial volume artifacts. Independent component analysis (ICA) has the advantage in automatically decomposing the signals into interpretable components. Recently group ICA technique has been applied to fMRI study and showed reduced variance caused by motion artifact and noise. In this work, we investigated the feasibility and efficacy of the use of group ICA technique to extract the AIF. Both simulated and in vivo data were analyzed in this study. The simulation data of eight phantoms were generated using randomized lesion locations and time activity curves. The clinical data were obtained from spin-echo EPI MR scans performed in seven normal subjects. Group ICA technique was applied to analyze data through concatenating across seven subjects. The AIFs were calculated from the weighted average of the signals in the region selected by ICA. Preliminary results of this study showed that group ICA technique could not extract accurate AIF information from regions around the vessel. The mismatched location of vessels within the group reduced the benefits of group study

GROUP DYNAMICS AND TEAM FUNCTIONING IN ORGANIZATIONAL CONTEXT

Directory of Open Access Journals (Sweden)

Raluca ZOLTAN

2015-07-01

Full Text Available In all kind of organization many activities are done by groups and teams. But how are they formed? What factors influence their existence and development? How members of groups and teams are selected? Which are the consequences in organizational context? In order to answer these questions, in the present paper we describe and analyze the main approaches regarding the formation of work groups and work teams (sociometric approach and group dynamics approach, the main factors that affects group dynamics and the FIRO model for evaluation the team members’ needs.

Complex dynamics in supervised work groups

Science.gov (United States)

Dal Forno, Arianna; Merlone, Ugo

2013-07-01

In supervised work groups many factors concur to determine productivity. Some of them may be economical and some psychological. According to the literature, the heterogeneity in terms of individual capacity seems to be one of the principal causes for chaotic dynamics in a work group. May sorting groups of people with same capacity for effort be a solution? In the organizational psychology literature an important factor is the engagement in the task, while expectations are central in the economics literature. Therefore, we propose a dynamical model which takes into account both engagement in the task and expectations. An important lesson emerges. The intolerance deriving from the exposure to inequity may not be only caused by differences in individual capacities, but also by these factors combined. Consequently, solutions have to be found in this new direction.

Group dynamics challenges: Insights from Biosphere 2 experiments

Science.gov (United States)

Nelson, Mark; Gray, Kathelin; Allen, John P.

2015-07-01

Successfully managing group dynamics of small, physically isolated groups is vital for long duration space exploration/habitation and for terrestrial CELSS (Controlled Environmental Life Support System) facilities with human participants. Biosphere 2 had important differences and shares some key commonalities with both Antarctic and space environments. There were a multitude of stress factors during the first two year closure experiment as well as mitigating factors. A helpful tool used at Biosphere 2 was the work of W.R. Bion who identified two competing modalities of behavior in small groups. Task-oriented groups are governed by conscious acceptance of goals, reality-thinking in relation to time and resources, and intelligent management of challenges. The opposing unconscious mode, the "basic-assumption" ("group animal") group, manifests through Dependency/Kill the Leader, Fight/Flight and Pairing. These unconscious dynamics undermine and can defeat the task group's goal. The biospherians experienced some dynamics seen in other isolated teams: factions developing reflecting personal chemistry and disagreements on overall mission procedures. These conflicts were exacerbated by external power struggles which enlisted support of those inside. Nevertheless, the crew evolved a coherent, creative life style to deal with some of the deprivations of isolation. The experience of the first two year closure of Biosphere 2 vividly illustrates both vicissitudes and management of group dynamics. The crew overrode inevitable frictions to creatively manage both operational and research demands and opportunities of the facility, thus staying 'on task' in Bion's group dynamics terminology. The understanding that Biosphere 2 was their life support system may also have helped the mission to succeed. Insights from the Biosphere 2 experience can help space and remote missions cope successfully with the inherent challenges of small, isolated crews.

Group dynamics challenges: Insights from Biosphere 2 experiments.

Science.gov (United States)

Nelson, Mark; Gray, Kathelin; Allen, John P

2015-07-01

Successfully managing group dynamics of small, physically isolated groups is vital for long duration space exploration/habitation and for terrestrial CELSS (Controlled Environmental Life Support System) facilities with human participants. Biosphere 2 had important differences and shares some key commonalities with both Antarctic and space environments. There were a multitude of stress factors during the first two year closure experiment as well as mitigating factors. A helpful tool used at Biosphere 2 was the work of W.R. Bion who identified two competing modalities of behavior in small groups. Task-oriented groups are governed by conscious acceptance of goals, reality-thinking in relation to time and resources, and intelligent management of challenges. The opposing unconscious mode, the "basic-assumption" ("group animal") group, manifests through Dependency/Kill the Leader, Fight/Flight and Pairing. These unconscious dynamics undermine and can defeat the task group's goal. The biospherians experienced some dynamics seen in other isolated teams: factions developing reflecting personal chemistry and disagreements on overall mission procedures. These conflicts were exacerbated by external power struggles which enlisted support of those inside. Nevertheless, the crew evolved a coherent, creative life style to deal with some of the deprivations of isolation. The experience of the first two year closure of Biosphere 2 vividly illustrates both vicissitudes and management of group dynamics. The crew overrode inevitable frictions to creatively manage both operational and research demands and opportunities of the facility, thus staying 'on task' in Bion's group dynamics terminology. The understanding that Biosphere 2 was their life support system may also have helped the mission to succeed. Insights from the Biosphere 2 experience can help space and remote missions cope successfully with the inherent challenges of small, isolated crews. Copyright © 2015 The Committee on

Climate change and group dynamics

NARCIS (Netherlands)

Postmes, Tom

2015-01-01

The characteristics and views of people sceptical about climate change have been analysed extensively. A study now confirms that sceptics in the US have some characteristics of a social movement, but shows that the same group dynamics propel believers

Technip. Group dynamics and activities. Competitive environment and strategic perspectives. Release - February 2017

International Nuclear Information System (INIS)

2017-02-01

After a synthesis which notably proposes a SWOT analysis of the Technip group, this report proposes a presentation of the Technip Group (general overview, presentation of activities per department, human resources, stock market data, and competitive environment). It gives an overview of the Technip group dynamics and of its activities through a presentation of an environment analysis (world oil demand and production, hydrocarbon prices), a presentation of the group activity (turnover, order takings, performance per activity pole, turnover per geographical area, operational income). It addresses important events and development axes: strategic axes, group restructuring, widening of service provision, R and D investments. Financial data are presented along with the main economic and financial indicators. Important statistical data are provided

Group adaptation, formal darwinism and contextual analysis.

Science.gov (United States)

Okasha, S; Paternotte, C

2012-06-01

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

Report of the working group on single-particle nonlinear dynamics

International Nuclear Information System (INIS)

Bazzani, A.; Bongini, L.; Corbett, J.; Dome, G.; Fedorova, A.; Freguglia, P.; Ng, K.; Ohmi, K.; Owen, H.; Papaphilippou, Y.; Robin, D.; Safranek, J.; Scandale, W.; Terebilo, A.; Turchetti, G.; Todesco, E.; Warnock, R.; Zeitlin, M.

1999-01-01

The Working Group on single-particle nonlinear dynamics has developed a set of tools to study nonlinear dynamics in a particle accelerator. The design of rings with large dynamic apertures is still far from automatic. The Working Group has concluded that nonlinear single-particle dynamics limits the performance of accelerators. (AIP) copyright 1999 American Institute of Physics

Multi-group dynamic quantum secret sharing with single photons

Energy Technology Data Exchange (ETDEWEB)

Liu, Hongwei [School of Science and State Key Laboratory of Information Photonics and Optical Communications, Beijing University of Posts and Telecommunications, Beijing 100876 (China); Ma, Haiqiang, E-mail: hqma@bupt.edu.cn [School of Science and State Key Laboratory of Information Photonics and Optical Communications, Beijing University of Posts and Telecommunications, Beijing 100876 (China); Wei, Kejin [School of Science and State Key Laboratory of Information Photonics and Optical Communications, Beijing University of Posts and Telecommunications, Beijing 100876 (China); Yang, Xiuqing [School of Science, Beijing Jiaotong University, Beijing 100044 (China); Qu, Wenxiu; Dou, Tianqi; Chen, Yitian; Li, Ruixue; Zhu, Wu [School of Science and State Key Laboratory of Information Photonics and Optical Communications, Beijing University of Posts and Telecommunications, Beijing 100876 (China)

2016-07-15

In this letter, we propose a novel scheme for the realization of single-photon dynamic quantum secret sharing between a boss and three dynamic agent groups. In our system, the boss can not only choose one of these three groups to share the secret with, but also can share two sets of independent keys with two groups without redistribution. Furthermore, the security of communication is enhanced by using a control mode. Compared with previous schemes, our scheme is more flexible and will contribute to a practical application. - Highlights: • A multi-group dynamic quantum secret sharing with single photons scheme is proposed. • Any one of the groups can be chosen to share secret through controlling the polarization of photons. • Two sets of keys can be shared simultaneously without redistribution.

Opinion dynamics within a virtual small group: the stubbornness effect

Science.gov (United States)

Guazzini, Andrea; Cini, Alessandro; Bagnoli, Franco; Ramasco, José

2015-09-01

The modeling of opinion dynamics is social systems has attracted a good deal of attention in the last decade. Even though based on intuition and observation, the mechanisms behind many of these models need solid empirical grounding. In this work, we investigate the relation among subjective variables (such as the personality), the dynamics of the affinity network dynamics, the communication patterns emerging throughout the social interactions and the opinions dynamics in a series of experiments with five small groups of ten people each. In order to ignite the discussion, the polemic topic of animal experimentation was proposed. The groups essentially polarized in two factions with a set of stubborn individuals (those not changing their opinions in time) playing the role of anchors. Our results suggest that the different layers present in the group dynamics (i.e., individual level, group dynamics and meso-communication) are deeply intermingled, specifically the stubbornness effect appears to be related to the dynamical features of the network topologies, and only in an undirected way to the personality of the participants.

Opinion dynamics within a virtual small group: the stubbornness effect

Directory of Open Access Journals (Sweden)

Andrea eGuazzini

2015-09-01

Full Text Available The modeling of opinion dynamics is social systems has attracted a good deal of attention in the last decade. Even though based on intuition and observation, the mechanisms behind many of these models need solid empirical grounding. In this work, we investigate the relation among subjective variables (such as the personality, the dynamics of the affinity network dynamics, the communication patterns emerging throughout the social interactions and the opinions dynamics in a series of experiments with five small groups of ten people each. In order to ignite the discussion, the polemic topic of animal experimentation was proposed. The groups essentially polarized in two factions with a set of stubborn individuals (those not changing their opinions in time playing the role of anchors. Our results suggest that the different layers present in the group dynamics (i.e., individual level, group dynamics and meso-communication are deeply intermingled, specifically the stubbornness effect appears to be related to the dynamical features of the network topologies, and only in an undirected way to the personality of the participants.

Rapid Prototyping of Social Group Dynamics in Multiagent Systems

DEFF Research Database (Denmark)

Rehm, Matthias; Endrass, Birgit

2009-01-01

In this article we present an engineering approach for the integration of social group dynamics in the behavior modeling of multiagent systems. To this end, a toolbox was created that brings together several theories from the social sciences, each focusing on different aspects of group dynamics. ...

Brain-to-Brain Synchrony Tracks Real-World Dynamic Group Interactions in the Classroom.

Science.gov (United States)

Dikker, Suzanne; Wan, Lu; Davidesco, Ido; Kaggen, Lisa; Oostrik, Matthias; McClintock, James; Rowland, Jess; Michalareas, Georgios; Van Bavel, Jay J; Ding, Mingzhou; Poeppel, David

2017-05-08

The human brain has evolved for group living [1]. Yet we know so little about how it supports dynamic group interactions that the study of real-world social exchanges has been dubbed the "dark matter of social neuroscience" [2]. Recently, various studies have begun to approach this question by comparing brain responses of multiple individuals during a variety of (semi-naturalistic) tasks [3-15]. These experiments reveal how stimulus properties [13], individual differences [14], and contextual factors [15] may underpin similarities and differences in neural activity across people. However, most studies to date suffer from various limitations: they often lack direct face-to-face interaction between participants, are typically limited to dyads, do not investigate social dynamics across time, and, crucially, they rarely study social behavior under naturalistic circumstances. Here we extend such experimentation drastically, beyond dyads and beyond laboratory walls, to identify neural markers of group engagement during dynamic real-world group interactions. We used portable electroencephalogram (EEG) to simultaneously record brain activity from a class of 12 high school students over the course of a semester (11 classes) during regular classroom activities (Figures 1A-1C; Supplemental Experimental Procedures, section S1). A novel analysis technique to assess group-based neural coherence demonstrates that the extent to which brain activity is synchronized across students predicts both student class engagement and social dynamics. This suggests that brain-to-brain synchrony is a possible neural marker for dynamic social interactions, likely driven by shared attention mechanisms. This study validates a promising new method to investigate the neuroscience of group interactions in ecologically natural settings. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Individual and group dynamics in purchasing activity

Science.gov (United States)

Gao, Lei; Guo, Jin-Li; Fan, Chao; Liu, Xue-Jiao

2013-01-01

As a major part of the daily operation in an enterprise, purchasing frequency is in constant change. Recent approaches on the human dynamics can provide some new insights into the economic behavior of companies in the supply chain. This paper captures the attributes of creation times of purchase orders to an individual vendor, as well as to all vendors, and further investigates whether they have some kind of dynamics by applying logarithmic binning to the construction of distribution plots. It’s found that the former displays a power-law distribution with approximate exponent 2.0, while the latter is fitted by a mixture distribution with both power-law and exponential characteristics. Obviously, two distinctive characteristics are presented for the interval time distribution from the perspective of individual dynamics and group dynamics. Actually, this mixing feature can be attributed to the fitting deviations as they are negligible for individual dynamics, but those of different vendors are cumulated and then lead to an exponential factor for group dynamics. To better describe the mechanism generating the heterogeneity of the purchase order assignment process from the objective company to all its vendors, a model driven by product life cycle is introduced, and then the analytical distribution and the simulation result are obtained, which are in good agreement with the empirical data.

Dynamic Network Logistic Regression: A Logistic Choice Analysis of Inter- and Intra-Group Blog Citation Dynamics in the 2004 US Presidential Election

OpenAIRE

Almquist, Zack W.; Butts, Carter T.

2013-01-01

Methods for analysis of network dynamics have seen great progress in the past decade. This article shows how Dynamic Network Logistic Regression techniques (a special case of the Temporal Exponential Random Graph Models) can be used to implement decision theoretic models for network dynamics in a panel data context. We also provide practical heuristics for model building and assessment. We illustrate the power of these techniques by applying them to a dynamic blog network sampled during the 2...

Symmetry breaking in the opinion dynamics of a multi-group project organization

International Nuclear Information System (INIS)

Zhu Zhen-Tao; Zhou Jing; Chen Xing-Guang; Li Ping

2012-01-01

A bounded confidence model of opinion dynamics in multi-group projects is presented in which each group's opinion evolution is driven by two types of forces: (i) the group's cohesive force which tends to restore the opinion back towards the initial status because of its company culture; and (ii) nonlinear coupling forces with other groups which attempt to bring opinions closer due to collaboration willingness. Bifurcation analysis for the case of a two-group project shows a cusp catastrophe phenomenon and three distinctive evolutionary regimes, i.e., a deadlock regime, a convergence regime, and a bifurcation regime in opinion dynamics. The critical value of initial discord between the two groups is derived to discriminate which regime the opinion evolution belongs to. In the case of a three-group project with a symmetric social network, both bifurcation analysis and simulation results demonstrate that if each pair has a high initial discord, instead of symmetrically converging to consensus with the increase of coupling scale as expected by Gabbay's result (Physica A 378 (2007) p. 125 Fig. 5), project organization (PO) may be split into two distinct clusters because of the symmetry breaking phenomenon caused by pitchfork bifurcations, which urges that apart from divergence in participants' interests, nonlinear interaction can also make conflict inevitable in the PO. The effects of two asymmetric level parameters are tested in order to explore the ways of inducing dominant opinion in the whole PO. It is found that the strong influence imposed by a leader group with firm faith on the flexible and open minded follower groups can promote the formation of a positive dominant opinion in the PO

Symmetry breaking in the opinion dynamics of a multi-group project organization

Science.gov (United States)

Zhu, Zhen-Tao; Zhou, Jing; Li, Ping; Chen, Xing-Guang

2012-10-01

A bounded confidence model of opinion dynamics in multi-group projects is presented in which each group's opinion evolution is driven by two types of forces: (i) the group's cohesive force which tends to restore the opinion back towards the initial status because of its company culture; and (ii) nonlinear coupling forces with other groups which attempt to bring opinions closer due to collaboration willingness. Bifurcation analysis for the case of a two-group project shows a cusp catastrophe phenomenon and three distinctive evolutionary regimes, i.e., a deadlock regime, a convergence regime, and a bifurcation regime in opinion dynamics. The critical value of initial discord between the two groups is derived to discriminate which regime the opinion evolution belongs to. In the case of a three-group project with a symmetric social network, both bifurcation analysis and simulation results demonstrate that if each pair has a high initial discord, instead of symmetrically converging to consensus with the increase of coupling scale as expected by Gabbay's result (Physica A 378 (2007) p. 125 Fig. 5), project organization (PO) may be split into two distinct clusters because of the symmetry breaking phenomenon caused by pitchfork bifurcations, which urges that apart from divergence in participants' interests, nonlinear interaction can also make conflict inevitable in the PO. The effects of two asymmetric level parameters are tested in order to explore the ways of inducing dominant opinion in the whole PO. It is found that the strong influence imposed by a leader group with firm faith on the flexible and open minded follower groups can promote the formation of a positive dominant opinion in the PO.

Social Group Dynamics and Patterns of Latin American Integration Processes

Directory of Open Access Journals (Sweden)

Sébastien Dubé

2017-04-01

Full Text Available This article proposes to incorporate social psychology elements with mainstream political science and international relations theories to help understand the contradictions related to the integration processes in Latin America. Through a theoretical analysis, it contributes to the challenge proposed by Dabène (2009 to explain the “resilience” of the Latin American regional integration process in spite of its “instability and crises.” Our main proposition calls for considering Latin America as a community and its regional organizations as “social groups.” In conclusion, three phenomena from the field of social psychology and particularly social group dynamics shed light on these contradictory patterns: the value of the group and the emotional bond, groupthink, and cognitive dissonance.

Interactive affective sharing versus non-interactive affective sharing in work groups : Comparative effects of group affect on work group performance and dynamics

NARCIS (Netherlands)

Klep, Annefloor; Wisse, Barbara; Van Der Flier, Henk

This study explores whether the dynamic path to group affect, which is characterized by interactive affective sharing processes, yields different effects on task performance and group dynamics than the static path to group affect, which arises from non-interactive affective sharing. The results of

Interactive affective sharing versus non-interactive affective sharing in work groups: Comparative effects of group affect on work group performance and dynamics

NARCIS (Netherlands)

Klep, A.H.M.; Wisse, B.M.; van der Flier, H.

2011-01-01

This study explores whether the dynamic path to group affect, which is characterized by interactive affective sharing processes, yields different effects on task performance and group dynamics than the static path to group affect, which arises from non-interactive affective sharing. The results of

Metastable structures and size effects in small group dynamics

Directory of Open Access Journals (Sweden)

Rosapia eLauro Grotto

2014-07-01

Full Text Available In his seminal works on group dynamics Bion defined a specific therapeutic setting allowing psychoanalytic observations on group phenomena. In describing the setting he proposed that the group was where his voice arrived. This physical limit was later made operative by assuming that the natural dimension of a therapeutic group is around 12 people. Bion introduced a theory of the group aspects of the mind in which proto-mental individual states spontaneously evolve into shared psychological states that are characterized by a series of features: 1 they emerge as a consequence of the natural tendency of (both conscious and unconscious emotions to combine into structured group patterns; 2 they have a certain degree of stability in time; 3 they tend to alternate so that the dissolution of one is rapidly followed by the emergence of another; 4 they can be described in qualitative terms according to the nature of the emotional mix that dominates the state, in structural terms by a kind of typical 'leadership’ pattern, and in 'cognitive’ terms by a set of implicit expectations that are helpful in explaining the group behavior (i.e. the group behaves 'as if’ it was assuming that…. Here we adopt a formal approach derived from Socio-physics in order to explore some of the structural and dynamic properties of this small group dynamics. We will described data from an analytic DS model simulating small group interactions of agents endowed with a very simplified emotional and cognitive dynamic in order to assess the following main points: 1 are metastable collective states allowed to emerge in the model and if so, under which conditions in the parameter space? 3 can these states be differentiated in structural terms? 3 to what extent are the emergent dynamic features of the systems dependent of the system size? We will finally discuss possible future applications of the quantitative descriptions of the interaction structure in the small group clinical

Metastable structures and size effects in small group dynamics.

Science.gov (United States)

Lauro Grotto, Rosapia; Guazzini, Andrea; Bagnoli, Franco

2014-01-01

In his seminal works on group dynamics Bion defined a specific therapeutic setting allowing psychoanalytic observations on group phenomena. In describing the setting he proposed that the group was where his voice arrived. This physical limit was later made operative by assuming that the natural dimension of a therapeutic group is around 12 people. Bion introduced a theory of the group aspects of the mind in which proto-mental individual states spontaneously evolve into shared psychological states that are characterized by a series of features: (1) they emerge as a consequence of the natural tendency of (both conscious and unconscious) emotions to combine into structured group patterns; (2) they have a certain degree of stability in time; (3) they tend to alternate so that the dissolution of one is rapidly followed by the emergence of another; (4) they can be described in qualitative terms according to the nature of the emotional mix that dominates the state, in structural terms by a kind of typical "leadership" pattern, and in "cognitive" terms by a set of implicit expectations that are helpful in explaining the group behavior (i.e., the group behaves "as if" it was assuming that). Here we adopt a formal approach derived from Socio-physics in order to explore some of the structural and dynamic properties of this small group dynamics. We will described data from an analytic DS model simulating small group interactions of agents endowed with a very simplified emotional and cognitive dynamic in order to assess the following main points: (1) are metastable collective states allowed to emerge in the model and if so, under which conditions in the parameter space? (2) can these states be differentiated in structural terms? (3) to what extent are the emergent dynamic features of the systems dependent of the system size? We will finally discuss possible future applications of the quantitative descriptions of the interaction structure in the small group clinical setting.

Exploring Challenging Group Dynamics in Participatory Design with Children

OpenAIRE

Van Mechelen, Maarten; Gielen, Matthieu; Vanden Abeele, Vero; Laenen, Ann; Zaman, Bieke

2014-01-01

This paper presents a structured way to evaluate challenging group or 'codesign dynamics' in participatory design processes with children. In the form of a critical reflection on a project in which 103 children were involved as design partners, we describe the most prevalent codesign dynamics. For example, some groups rush too quickly towards consensus to safeguard group cohesiveness instead of examining other choice alternatives (i.e., groupthink). Besides 'groupthink' we describe five more ...

Effect of social group dynamics on contagion

Science.gov (United States)

Zhao, Zhenyuan; Calderón, J. P.; Xu, Chen; Zhao, Guannan; Fenn, Dan; Sornette, Didier; Crane, Riley; Hui, Pak Ming; Johnson, Neil F.

2010-05-01

Despite the many works on contagion phenomena in both well-mixed systems and heterogeneous networks, there is still a lack of understanding of the intermediate regime where social group structures evolve on a similar time scale to individual-level transmission. We address this question by considering the process of transmission through a model population comprising social groups which follow simple dynamical rules for growth and breakup. Despite the simplicity of our model, the profiles produced bear a striking resemblance to a wide variety of real-world examples—in particular, empirical data that we have obtained for social (i.e., YouTube), financial (i.e., currency markets), and biological (i.e., colds in schools) systems. The observation of multiple resurgent peaks and abnormal decay times is qualitatively reproduced within the model simply by varying the time scales for group coalescence and fragmentation. We provide an approximate analytic treatment of the system and highlight a novel transition which arises as a result of the social group dynamics.

Maintenance grouping strategy for multi-component systems with dynamic contexts

International Nuclear Information System (INIS)

Vu, Hai Canh; Do, Phuc; Barros, Anne; Bérenguer, Christophe

2014-01-01

This paper presents a dynamic maintenance grouping strategy for multi-component systems with both “positive” and “negative” economic dependencies. Positive dependencies are commonly due to setup cost whereas negative dependencies are related to shutdown cost. Actually, grouping maintenance activities can save part of the setup cost, but can also in the same time increase the shutdown cost. Until now, both types of dependencies have been jointly taken into account only for simple system structures as pure series. The first aim of this paper is to investigate the case of systems with any combination of basic structures (series, parallel or k-out-of n structures). A cost model and a heuristic optimization scheme are proposed since the optimization of maintenance grouping strategy for such multi-component systems leads to a NP-complete problem. Then the second objective is to propose a finite horizon (dynamic) model in order to optimize online the maintenance strategy in the presence of dynamic contexts (change of the environment, the working condition, the production process, etc). A numerical example of a 16-component system is finally introduced to illustrate the use and the advantages of the proposed approach in the maintenance optimization framework. - Highlights: • A dynamic grouping maintenance strategy for complex structure systems is proposed. • Impacts of the system structure on grouping maintenance are investigated. • A grouping approach based on the rolling horizon and GA algorithm is proposed. • Different dynamic contexts and their impacts on grouping maintenance are studied. • The proposed approach can help to update the maintenance planning in dynamic contexts

Nonlinear dynamics in the perceptual grouping of connected surfaces.

Science.gov (United States)

Hock, Howard S; Schöner, Gregor

2016-09-01

Evidence obtained using the dynamic grouping method has shown that the grouping of an object's connected surfaces has properties characteristic of a nonlinear dynamical system. When a surface's luminance changes, one of its boundaries is perceived moving across the surface. The direction of this dynamic grouping (DG) motion indicates which of two flanking surfaces has been grouped with the changing surface. A quantitative measure of overall grouping strength (affinity) for adjacent surfaces is provided by the frequency of DG motion perception in directions promoted by the grouping variables. It was found that: (1) variables affecting surface grouping for three-surface objects evolve over time, settling at stable levels within a single fixation, (2) how often DG motion is perceived when a surface's luminance is perturbed (changed) depends on the pre-perturbation affinity state of the surface grouping, (3) grouping variables promoting the same surface grouping combine cooperatively and nonlinearly (super-additively) in determining the surface grouping's affinity, (4) different DG motion directions during different trials indicate that surface grouping can be bistable, which implies that inhibitory interactions have stabilized one of two alternative surface groupings, and (5) when alternative surface groupings have identical affinity, stochastic fluctuations can break the symmetry and inhibitory interactions can then stabilize one of the surface groupings, providing affinity levels are not too high (which results in bidirectional DG motion). A surface-grouping network is proposed within which boundaries vary in salience. Low salience or suppressed boundaries instantiate surface grouping, and DG motion results from changes in boundary salience. Copyright © 2015 Elsevier Ltd. All rights reserved.

Total. Group dynamics and activities. Competitive environment and strategic perspectives. Release - July 2017

International Nuclear Information System (INIS)

2017-07-01

After a synthesis which notably proposes a SWOT analysis of the Total group, this report proposes a presentation of the Total Group (general overview, presentation of activities, human resources, shareholder structure and stock market data, competitive environment). It gives an overview of the Total group dynamics and of its activities through a presentation of an environment analysis (world oil demand, refining-chemistry activity, hydrocarbon prices), a presentation of the group activity (turnover, turnover per segment, operational income and financial results of competitors). It comments important events and development axes: four strategic orientations, strengthening of the upstream pole, restructuring of refining and chemical activities, widening of the energy provision, consolidation of positions in the marketing and services sector. Financial data are presented along with the main economic and financial indicators. Important statistical data are provided

Areva. Group dynamics and activities. Competitive environment and strategic perspectives. Release - October 2016

International Nuclear Information System (INIS)

2016-10-01

After a synthesis which notably proposes a SWOT analysis of the Areva group, this report proposes a presentation of the Areva Group (general overview, mining, upstream and downstream poles, shareholder structure and stock market data, competitive environment). It gives an overview of the Areva group dynamics and of its activities through a presentation of an environment analysis (world electric power production, uranium production and consumption, operated nuclear plants in the world), a presentation of the group activity (turnover and order backlog, turnover per segment and per geographical area, operational and net income). It indicates important events and comments development axes: strategic orientations, new partnership with EDF, stronger presence in China, asset disposal, and organisation optimisation. Financial data are presented along with the main economic and financial indicators. Important statistical data are provided

STATISTICAL TOOLS FOR CLASSIFYING GALAXY GROUP DYNAMICS

International Nuclear Information System (INIS)

Hou, Annie; Parker, Laura C.; Harris, William E.; Wilman, David J.

2009-01-01

The dynamical state of galaxy groups at intermediate redshifts can provide information about the growth of structure in the universe. We examine three goodness-of-fit tests, the Anderson-Darling (A-D), Kolmogorov, and χ 2 tests, in order to determine which statistical tool is best able to distinguish between groups that are relaxed and those that are dynamically complex. We perform Monte Carlo simulations of these three tests and show that the χ 2 test is profoundly unreliable for groups with fewer than 30 members. Power studies of the Kolmogorov and A-D tests are conducted to test their robustness for various sample sizes. We then apply these tests to a sample of the second Canadian Network for Observational Cosmology Redshift Survey (CNOC2) galaxy groups and find that the A-D test is far more reliable and powerful at detecting real departures from an underlying Gaussian distribution than the more commonly used χ 2 and Kolmogorov tests. We use this statistic to classify a sample of the CNOC2 groups and find that 34 of 106 groups are inconsistent with an underlying Gaussian velocity distribution, and thus do not appear relaxed. In addition, we compute velocity dispersion profiles (VDPs) for all groups with more than 20 members and compare the overall features of the Gaussian and non-Gaussian groups, finding that the VDPs of the non-Gaussian groups are distinct from those classified as Gaussian.

Capturing dynamic processes of change in GROW mutual help groups for mental health.

Science.gov (United States)

Finn, Lizzie D; Bishop, Brian J; Sparrow, Neville

2009-12-01

The need for a model that can portray dynamic processes of change in mutual help groups for mental health (MHGMHs) is emphasized. A dynamic process model has the potential to capture a more comprehensive understanding of how MHGMHs may assist their members. An investigation into GROW, a mutual help organization for mental health, employed ethnographic, phenomenological and collaborative research methods. The study examined how GROW impacts on psychological well being. Study outcomes aligned with the social ecological paradigm (Maton in Understanding the self-help organization: frameworks and findings. Sage, Thousand Oaks 1994) indicating multifactorial processes of change at and across three levels of analysis: group level, GROW program/community level and individual level. Outcome themes related to life skills acquisition and a change in self-perception in terms of belonging within community and an increased sense of personal value. The GROW findings are used to assist development of a dynamic multi-dimensional process model to explain how MHGMHs may promote positive change.

Spontaneous formation of dynamical groups in an adaptive networked system

International Nuclear Information System (INIS)

Li Menghui; Guan Shuguang; Lai, C-H

2010-01-01

In this work, we investigate a model of an adaptive networked dynamical system, where the coupling strengths among phase oscillators coevolve with the phase states. It is shown that in this model the oscillators can spontaneously differentiate into two dynamical groups after a long time evolution. Within each group, the oscillators have similar phases, while oscillators in different groups have approximately opposite phases. The network gradually converts from the initial random structure with a uniform distribution of connection strengths into a modular structure that is characterized by strong intra-connections and weak inter-connections. Furthermore, the connection strengths follow a power-law distribution, which is a natural consequence of the coevolution of the network and the dynamics. Interestingly, it is found that if the inter-connections are weaker than a certain threshold, the two dynamical groups will almost decouple and evolve independently. These results are helpful in further understanding the empirical observations in many social and biological networks.

Dynamical theory of dense groups of galaxies

Science.gov (United States)

Mamon, Gary A.

1990-01-01

It is well known that galaxies associate in groups and clusters. Perhaps 40% of all galaxies are found in groups of 4 to 20 galaxies (e.g., Tully 1987). Although most groups appear to be so loose that the galaxy interactions within them ought to be insignificant, the apparently densest groups, known as compact groups appear so dense when seen in projection onto the plane of the sky that their members often overlap. These groups thus appear as dense as the cores of rich clusters. The most popular catalog of compact groups, compiled by Hickson (1982), includes isolation among its selection critera. Therefore, in comparison with the cores of rich clusters, Hickson's compact groups (HCGs) appear to be the densest isolated regions in the Universe (in galaxies per unit volume), and thus provide in principle a clean laboratory for studying the competition of very strong gravitational interactions. The $64,000 question here is then: Are compact groups really bound systems as dense as they appear? If dense groups indeed exist, then one expects that each of the dynamical processes leading to the interaction of their member galaxies should be greatly enhanced. This leads us to the questions: How stable are dense groups? How do they form? And the related question, fascinating to any theorist: What dynamical processes predominate in dense groups of galaxies? If HCGs are not bound dense systems, but instead 1D change alignments (Mamon 1986, 1987; Walke & Mamon 1989) or 3D transient cores (Rose 1979) within larger looser systems of galaxies, then the relevant question is: How frequent are chance configurations within loose groups? Here, the author answers these last four questions after comparing in some detail the methods used and the results obtained in the different studies of dense groups.

EDF. Group dynamics and activities. Competitive environment and strategic perspectives. Release - October 2017

International Nuclear Information System (INIS)

2017-10-01

After a synthesis, this report proposes a presentation of the EDF Group (general overview, activities, human resources, share-holding structure, stock market data). It gives an overview of the EDF Group dynamics and of its activities: environment analysis (world electric power production, power consumption in France, regulated and spot prices, turnover in France and per area and market segment), performance analysis, and competitive analysis (comparison with the main European energy companies). It analyses the different development axes and discusses main events regarding the consolidation of nuclear activities, investments in renewable energies, withdrawal from coal and fuel, diversification in energy services, and financial consolidation. Financial data are presented along with the main economic and financial indicators. Important statistical data are provided

Bifurcation and complex dynamics of a discrete-time predator-prey system involving group defense

Directory of Open Access Journals (Sweden)

S. M. Sohel Rana

2015-09-01

Full Text Available In this paper, we investigate the dynamics of a discrete-time predator-prey system involving group defense. The existence and local stability of positive fixed point of the discrete dynamical system is analyzed algebraically. It is shown that the system undergoes a flip bifurcation and a Neimark-Sacker bifurcation in the interior of R+2 by using bifurcation theory. Numerical simulation results not only show the consistence with the theoretical analysis but also display the new and interesting dynamical behaviors, including phase portraits, period-7, 20-orbits, attracting invariant circle, cascade of period-doubling bifurcation from period-20 leading to chaos, quasi-periodic orbits, and sudden disappearance of the chaotic dynamics and attracting chaotic set. The Lyapunov exponents are numerically computed to characterize the complexity of the dynamical behaviors.

Dynamic Analysis of a Pendulum Dynamic Automatic Balancer

Directory of Open Access Journals (Sweden)

Jin-Seung Sohn

2007-01-01

Full Text Available The automatic dynamic balancer is a device to reduce the vibration from unbalanced mass of rotors. Instead of considering prevailing ball automatic dynamic balancer, pendulum automatic dynamic balancer is analyzed. For the analysis of dynamic stability and behavior, the nonlinear equations of motion for a system are derived with respect to polar coordinates by the Lagrange's equations. The perturbation method is applied to investigate the dynamic behavior of the system around the equilibrium position. Based on the linearized equations, the dynamic stability of the system around the equilibrium positions is investigated by the eigenvalue analysis.

Dynamical evolution of clusters with two stellar groups

Energy Technology Data Exchange (ETDEWEB)

Angeletti, L; Giannone, P. (Rome Univ. (Italy))

1977-08-01

The generalization of the fluid-dynamical approach from one-component star clusters to clusters with several stellar groups (as far as the star masses are concerned) has been applied to the study of two-component clusters. Rather extreme values of stellar masses and masses of groups were chosen in order to emphasize the different dynamical evolutions and asymptotic behaviors. Escape of stars from clusters and the problem of equipartition of kinetic energy among the two star groups are discussed. Comparisons of the main features of the results with those obtained by other authors have shown a good agreement. Some characteristic properties of the last computed models with an age of 18x10/sup 9/ yr have been pointed out and discussed in relation with some observed features of galactic globular clusters.

How milk-fed dairy calves perform in stable versus dynamic groups

DEFF Research Database (Denmark)

Pedersen, Rikke Engelbrecht; Sørensen, Jan Tind; Skjøth, F

2009-01-01

The objective of the present field trial was to compare calf performance among pre-weaned calves in two different group housing systems, stable groups ("all in-all out") and dynamic groups (continuous introduction). Performance data was collected from 484 calves randomly assigned to the two syste....../days). The prevalence of both diarrhoea and respiratory disease were more than twice as high among calves in dynamic groups compared to calves in stable groups....

Dynamical interpretation of nonrelativistic conformal groups

International Nuclear Information System (INIS)

Andrzejewski, K.; Gonera, J.

2013-01-01

It is shown that N-Galilean conformal algebra with N odd and nontrivial central charge is the maximal symmetry algebra for higher derivative free theory both on classical and quantum levels. By maximal symmetry algebra the Lie algebra of the maximal group of space–time symmetry transformations is understood which preserves higher order free dynamics

Engie. Group dynamics and activities. Competitive environment and strategic perspectives. Release - October 2017

International Nuclear Information System (INIS)

2017-09-01

After a synthesis, this report proposes a presentation of the Engie Group (general overview, activities in the different parts of the world, evolution of human resources, share-holding structure, stock market data, high management, competitive environment). It gives an overview of the Engie group dynamics and of its activities through a presentation of an environment analysis (world energy market, European gas and electricity market, gas consumption in France, regulated tariffs and spot prices, temperatures in France, regulatory evolutions), a presentation of the group activity (turnover in France, gas and electricity sales, turnover per area and market segment), a performance analysis (operating income), and a competitive analysis (comparison with the main European energy companies). It analyses the different development axes and discusses main events regarding Engie's strategy, the implementation of a large asset disposal, how Engie gets on the path of renewable energies, and the development of energy services. Financial data are presented along with the main economic and financial indicators. Important statistical data are provided

Perspectives of Community Co-Researchers About Group Dynamics and Equitable Partnership Within a Community-Academic Research Team.

Science.gov (United States)

Vaughn, Lisa M; Jacquez, Farrah; Zhen-Duan, Jenny

2018-04-01

Equitable partnership processes and group dynamics, including individual, relational, and structural factors, have been identified as key ingredients to successful community-based participatory research partnerships. The purpose of this qualitative study was to investigate the key aspects of group dynamics and partnership from the perspectives of community members serving as co-researchers. Semistructured, in-depth interviews were conducted with 15 Latino immigrant co-researchers from an intervention project with Latinos Unidos por la Salud (LU-Salud), a community research team composed of Latino immigrant community members and academic investigators working in a health research partnership. A deductive framework approach guided the interview process and qualitative data analysis. The LU-Salud co-researchers described relationships, personal growth, beliefs/identity motivation (individual dynamics), coexistence (relational dynamics), diversity, and power/resource sharing (structural dynamics) as key foundational aspects of the community-academic partnership. Building on existing CBPR and team science frameworks, these findings demonstrate that group dynamics and partnership processes are fundamental drivers of individual-level motivation and meaning making, which ultimately sustain efforts of community partners to engage with the research team and also contribute to the achievement of intended research outcomes.

Analyzing repeated measures data on individuals nested within groups: accounting for dynamic group effects.

Science.gov (United States)

Bauer, Daniel J; Gottfredson, Nisha C; Dean, Danielle; Zucker, Robert A

2013-03-01

Researchers commonly collect repeated measures on individuals nested within groups such as students within schools, patients within treatment groups, or siblings within families. Often, it is most appropriate to conceptualize such groups as dynamic entities, potentially undergoing stochastic structural and/or functional changes over time. For instance, as a student progresses through school, more senior students matriculate while more junior students enroll, administrators and teachers may turn over, and curricular changes may be introduced. What it means to be a student within that school may thus differ from 1 year to the next. This article demonstrates how to use multilevel linear models to recover time-varying group effects when analyzing repeated measures data on individuals nested within groups that evolve over time. Two examples are provided. The 1st example examines school effects on the science achievement trajectories of students, allowing for changes in school effects over time. The 2nd example concerns dynamic family effects on individual trajectories of externalizing behavior and depression. PsycINFO Database Record (c) 2013 APA, all rights reserved.

Group dynamics in a long-term blind endeavor on Earth: An analog for space missions (Lewis & Clark Expedition group dynamic analysis)

Science.gov (United States)

Allner, M.; Rygalov, V.

2008-12-01

suggested distinguishable mission phase model, the Lewis and Clark Expedition will be analyzed for similarities to these space findings. Factors of consideration in support of this analysis involve an understanding of the leadership qualities of Lewis and Clark (and relations established and maintained with one another), the selection and diversity of their crew, and the group dynamics that were developed and maintained so carefully during the expedition. With this knowledge and understanding one can gain enormous insights useful in the planning and preparation for future long-duration space exploratory missions with high level of autonomy, mobility, minimal primary life support supply and high dependence on material re-circulation and In-Situ Resource Utilization approach.

Teacher’s action zone in facilitating group dynamics

Directory of Open Access Journals (Sweden)

Dagmara Gałajda

2012-01-01

Full Text Available As believed by many researchers (Dörnyei & Murphey 2003, Hadfield 1992, classroom climate is strongly determined by the dynamics of the learning group and its development over time. For this reason, the role of the teacher in facilitating group processes seems to be of primary importance since it is the teacher who has long been regarded as the group leader in both teacher-centred and learner-centred classrooms.The presentation focuses not only on positive but also on negative forms of classroom dynamics together with management techniques for dealing with conflicts, educational alienation and psychological defensiveness. This, in turn, leads to the concept of facilitator style based on Heron’s (2006 model of facilitation, which consists of six dimensions and three modes. In the paper particular emphasis is placed on the presentation and comparison of various theories of leadership, namely Heron’s system of facilitation, Hersey and Blanchard’s situational-leadership theory (1982 and Bass and Avolio’s transactional versus transformational leadership theory (1984.

Multidimensional (OLAP) Analysis for Designing Dynamic Learning Strategy

Science.gov (United States)

Rozeva, A.; Deliyska, B.

2010-10-01

Learning strategy in an intelligent learning system is generally elaborated on the basis of assessment of the following factors: learner's time for reaction, content of the learning object, amount of learning material in a learning object, learning object specification, e-learning medium and performance control. Current work proposes architecture for dynamic learning strategy design by implementing multidimensional analysis model of learning factors. The analysis model concerns on-line analytical processing (OLAP) of learner's data structured as multidimensional cube. Main components of the architecture are analysis agent for performing the OLAP operations on learner data cube, adaptation generator and knowledge selection agent for performing adaptive navigation in the learning object repository. The output of the analysis agent is involved in dynamic elaboration of learning strategy that fits best to learners profile and behavior. As a result an adaptive learning path for individual learner and for learner groups is generated.

Group Dynamic Assessment (G-DA: The Case for the Development of Control over the Past Tense

Directory of Open Access Journals (Sweden)

Ehsan Mehri

2015-09-01

Full Text Available The introduction of dynamic assessment within sociocultural theory opened a new door toward looking at the relationship between the teaching and assessment. The dialectic relationship between the two processes provides previously unfound information regarding the assessment and the development of the learners. However, the implementation of the interactionist dynamic assessment has carried some difficulties in class in general and the groups in particular. The current study tries to address the effect of group dynamic assessment on the development of the control over the past tense; therefore, it is two-folded in the aim. Not only does it work as a practical sample of group dynamic assessment in class, but also it seeks to analyze its effect on the development of control over the past tense. To this end, three learners at the levels of elementary, low-intermediate, and intermediate general proficiency were asked to read a novel and retell the story. The dynamic intervention provided by the teacher during the story retelling was later evaluated in the transcendence tasks of writing. The Friedman test indicated that the three learners had significant development in their control over the past tense in their writing. Moreover, the qualitative analysis of the interactions suggests that the learners changed their role from the mere receivers of the teacher's mediator into the active providers of mediation to other group members. Also, they developed their understanding of the concept of the past tense through implementing it in transcendence tasks of writing.

Addressing group dynamics in a brief motivational intervention for college student drinkers.

Science.gov (United States)

Faris, Alexander S; Brown, Janice M

2003-01-01

Previous research indicates that brief motivational interventions for college student drinkers may be less effective in group settings than individual settings. Social psychological theories about counterproductive group dynamics may partially explain this finding. The present study examined potential problems with group motivational interventions by comparing outcomes from a standard group motivational intervention (SGMI; n = 25), an enhanced group motivational intervention (EGMI; n = 27) designed to suppress counterproductive processes, and a no intervention control (n = 23). SGMI and EGMI participants reported disruptive group dynamics as evidenced by low elaboration likelihood, production blocking, and social loafing, though the level of disturbance was significantly lower for EGMI individuals (p = .001). Despite counteracting group dynamics in the EGMI condition, participants in the two interventions were statistically similar in post-intervention problem recognition and future drinking intentions. The results raise concerns over implementing individually-based interventions in group settings without making necessary adjustments.

Modelling animal group fission using social network dynamics.

Directory of Open Access Journals (Sweden)

Cédric Sueur

Full Text Available Group life involves both advantages and disadvantages, meaning that individuals have to compromise between their nutritional needs and their social links. When a compromise is impossible, the group splits in order to reduce conflict of interests and favour positive social interactions between its members. In this study we built a dynamic model of social networks to represent a succession of temporary fissions involving a change in social relations that could potentially lead to irreversible group fission (i.e. no more group fusion. This is the first study that assesses how a social network changes according to group fission-fusion dynamics. We built a model that was based on different parameters: the group size, the influence of nutritional needs compared to social needs, and the changes in the social network after a temporary fission. The results obtained from this theoretical data indicate how the percentage of social relation transfer, the number of individuals and the relative importance of nutritional requirements and social links influence the average number of days before irreversible fission occurs. The greater the nutritional needs and the higher the transfer of social relations during temporary fission, the fewer days will be observed before an irreversible fission. It is crucial to bridge the gap between the individual and the population level if we hope to understand how simple, local interactions may drive ecological systems.

Individual killer whale vocal variation during intra-group behavioral dynamics

Science.gov (United States)

Grebner, Dawn M.

The scientific goal of this dissertation was to carefully study the signal structure of killer whale communications and vocal complexity and link them to behavioral circumstances. The overall objective of this research sought to provide insight into killer whale call content and usage which may be conveying information to conspecifics in order to maintain group cohesion. Data were collected in the summers of 2006 and 2007 in Johnstone Strait, British Columbia. For both individuals and small groups, vocalizations were isolated using a triangular hydrophone array and the behavioral movement patterns were captured by a theodolite and video camera positioned on a cliff overlooking the hyrophone locations. This dissertation is divided into four analysis chapters. In Chapter 3, discriminant analysis was used to validate the four N04 call subtypes which were originally parsed due to variations in slope segments. The first two functions of the discriminant analysis explained 97% of the variability. Most of the variability for the N04 call was found in the front convex and the terminal portions of the call, while very little variability was found in the center region of the call. This research revealed that individual killer whales produced multiple subtypes of the N04 call. No correlations of behaviors to acoustic parameters obtained were found. The aim of the Chapter 4 was to determine if killer whale calling behavior varied prior to and after the animals had joined. Pulsed call rates were found to be greater pre- compared to post-joining events. Two-way vocal exchanges were more common occurring 74% of the time during pre-joining events. In Chapter 5, initiated and first response to calls varied between age/sex class groups when mothers were separated from an offspring. Solo mothers and calves initiated pulsed calls more often than they responded. Most of the no vocal responses were due to mothers who were foraging. Finally, observations of the frequency split in N04

Structure and Dynamics of Humpback Whales Competitive Groups in Ecuador

Directory of Open Access Journals (Sweden)

Fernando Félix

2015-02-01

Full Text Available We assessed the social structure and behavior of humpback whale (Megaptera novaeangliae competitive groups off Ecuador between July and August 2010. During this time we followed 185 whales in 22 competitive groups for 41.45 hr. The average group size was 8.4 animals (SD = 2.85. The average sighting time was 113.05 min/group (SD = 47.1. We used photographs of dorsal fins and video to record interactions and estimate an association index (AI between each pair of whales within the groups. Sightings were divided into periods, which were defined by changes in group membership. On average, group composition changed every 30.2 min, which confirms that the structure of competitive groups is highly dynamic. Interactions between escorts characterized by low level of aggression. At least 60% of escorts joined or left together the group in small subunits between two and five animals, suggesting some type of cooperative association. Although singletons, as well as pairs or trios were able to join competitive groups at any moment, escorts that joined together were able to stay longer with the group and displace dominant escorts. Genetic analysis showed that in three occasions more than one female was present within a competitive group, suggesting either males are herding females or large competitive groups are formed by subunits. Males and females performed similar surface displays. We propose that competition and cooperation are interrelated in humpback whales’ competitive groups and that male cooperation would be an adaptive strategy either to displace dominant escorts or to fend off challengers.

Cluster analysis of word frequency dynamics

Science.gov (United States)

Maslennikova, Yu S.; Bochkarev, V. V.; Belashova, I. A.

2015-01-01

This paper describes the analysis and modelling of word usage frequency time series. During one of previous studies, an assumption was put forward that all word usage frequencies have uniform dynamics approaching the shape of a Gaussian function. This assumption can be checked using the frequency dictionaries of the Google Books Ngram database. This database includes 5.2 million books published between 1500 and 2008. The corpus contains over 500 billion words in American English, British English, French, German, Spanish, Russian, Hebrew, and Chinese. We clustered time series of word usage frequencies using a Kohonen neural network. The similarity between input vectors was estimated using several algorithms. As a result of the neural network training procedure, more than ten different forms of time series were found. They describe the dynamics of word usage frequencies from birth to death of individual words. Different groups of word forms were found to have different dynamics of word usage frequency variations.

Cluster analysis of word frequency dynamics

International Nuclear Information System (INIS)

Maslennikova, Yu S; Bochkarev, V V; Belashova, I A

2015-01-01

This paper describes the analysis and modelling of word usage frequency time series. During one of previous studies, an assumption was put forward that all word usage frequencies have uniform dynamics approaching the shape of a Gaussian function. This assumption can be checked using the frequency dictionaries of the Google Books Ngram database. This database includes 5.2 million books published between 1500 and 2008. The corpus contains over 500 billion words in American English, British English, French, German, Spanish, Russian, Hebrew, and Chinese. We clustered time series of word usage frequencies using a Kohonen neural network. The similarity between input vectors was estimated using several algorithms. As a result of the neural network training procedure, more than ten different forms of time series were found. They describe the dynamics of word usage frequencies from birth to death of individual words. Different groups of word forms were found to have different dynamics of word usage frequency variations

Modelling of the turbo-generator groups dynamical behaviour. Application to the ARABELLE turbine of the N4 1400 MW unit

International Nuclear Information System (INIS)

Bediou, J.

1993-01-01

Simulation of the dynamical behaviour of the EDF turbogenerator groups is based on developments concerning bearing behaviour and shaft line dynamics. A provisional model for the ARABELLE turbine dynamic behaviour is derived. The detailed representation of all the components allows for a fine analysis of the different effects and the evaluation of the stresses transmitted to the structure in anomalistic operating conditions

Group Dynamics in the Interior Design Studio: Student Perceptions

Science.gov (United States)

Hill, Caroline

2008-01-01

This article presents the findings of a study measuring the classroom climates in collegiate interior design studios and considers these findings within the group dynamics theory framework. Three groups of students completed the College Classroom Environment Scales (CCES) questionnaire. Five of the six CCES subscale F ratios were statistically…

Dynamic analysis program for frame structure

International Nuclear Information System (INIS)

Ando, Kozo; Chiba, Toshio

1975-01-01

A general purpose computer program named ISTRAN/FD (Isub(HI) STRucture ANalysis/Frame structure, Dynamic analysis) has been developed for dynamic analysis of three-dimensional frame structures. This program has functions of free vibration analysis, seismic response analysis, graphic display by plotter and CRT, etc. This paper introduces ISTRAN/FD; examples of its application are shown with various problems : idealization of the cantilever, dynamic analysis of the main tower of the suspension bridge, three-dimensional vibration in the plate girder bridge, seismic response in the boiler steel structure, and dynamic properties of the underground LNG tank. In this last example, solid elements, in addition to beam elements, are especially used for the analysis. (auth.)

Facebook Groups as a Powerful and Dynamic Tool in Medical Education: Mixed-Method Study

Science.gov (United States)

Schmidbauer, Moritz; Gradel, Maximilian; Ferch, Sabine; Antón, Sofía; Hoppe, Boj; Pander, Tanja; von der Borch, Philip; Pinilla, Severin; Fischer, Martin; Dimitriadis, Konstantinos

2017-01-01

Background Social networking sites, in particular Facebook, are not only predominant in students’ social life but are to varying degrees interwoven with the medical curriculum. Particularly, Facebook groups have been identified for their potential in higher education. However, there is a paucity of data on user types, content, and dynamics of study-related Facebook groups. Objective The aim of this study was to identify the role of study-related Facebook group use, characterize medical students that use or avoid using Facebook groups (demographics, participation pattern, and motivation), and analyze student posting behavior, covered topics, dynamics, and limitations in Facebook groups with regards to educational usage. Methods Using a multi-method approach (interviews, focus groups, and qualitative and quantitative analysis of Facebook posts), we analyzed two representative Facebook groups of medical preclinical semesters at Ludwig-Maximilians-University (LMU) Munich. Facebook primary posts and replies over one semester were extracted and evaluated by using thematic content analysis. We developed and applied a coding scheme for studying the frequency and distribution of these posts. Additionally, we interviewed students with various degrees of involvement in the groups, as well as “new minorities,” students not registered on Facebook. Results Facebook groups seem to have evolved as the main tool for medical students at LMU to complement the curriculum and to discuss study-related content. These Facebook groups are self-organizing and quickly adapt to organizational or subject-related challenges posed by the curriculum. A wide range of topics is covered, with a dominance of organization-related posts (58.35% [6916/11,853] of overall posts). By measuring reply rates and comments per category, we were able to identify learning tips and strategies, material sharing, and course content discussions as the most relevant categories. Rates of adequate replies in these

Formal analysis of design process dynamics

NARCIS (Netherlands)

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

2010-01-01

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

Formal Analysis of Design Process Dynamics

NARCIS (Netherlands)

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

2010-01-01

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

RG analysis of magnetic catalysis in dynamical symmetry breaking

International Nuclear Information System (INIS)

Hong, Deog Ki; Kim, Youngman

1996-01-01

We perform the renormalization group analysis on the dynamical symmetry breaking under strong external magnetic field, studied recently by Gusynin, Miransky and Shovkovy. We find that any attractive four-Fermi interaction becomes strong in the low energy, thus leading to dynamical symmetry breaking. When the four-Fermi interaction is absent, the β-function for the electromagnetic coupling vanishes in the leading order in 1/N. By solving the Schwinger-Dyson equation for the fermion propagator, we show that in 1/N expansion, for any electromagnetic coupling, dynamical symmetry breaking occurs due to the presence of Landau energy gap by the external magnetic field. 5 refs

The dynamics of access to groups in working memory.

Science.gov (United States)

Farrell, Simon; Lelièvre, Anna

2012-11-01

The finding that participants leave a pause between groups when attempting serial recall of temporally grouped lists has been taken to indicate access to a hierarchical representation of the list in working memory. An alternative explanation is that the dynamics of serial recall solely reflect output (rather than memorial) processes, with the temporal pattern at input merely suggesting a basis for the pattern of output buffering. Three experiments are presented here that disentangle input structure from output buffering in serial recall. In Experiment 1, participants were asked to recall a subset of visually presented digits from a temporally grouped list in their original order, where either within-group position or group position was kept constant. In Experiment 2, participants performed more standard serial recall of spoken digits, and input and output position were dissociated by asking participants to initiate recall from a post-cued position in the list. In Experiment 3, participants were asked to serially recall temporally grouped lists of visually presented digits where the grouping structure was unpredictable, under either articulatory suppression or silent conditions. The 3 experiments point to a tight linkage between implied memorial structures (i.e., the pattern of grouping at encoding) and the output structure implied by retrieval times and call into question a purely motoric account of the dynamics of recall.

Dynamics on the group manifolds and path integral

International Nuclear Information System (INIS)

Marinov, M.S.; Terentyev, M.V.

1979-01-01

Classical and quantum dynamics onn the compact simple Lie group and on the sphere of arbitrary dimensionality are considered. The accuracy of the semiclassical approximation for Green functions is discussed. Various path integral representations of the Green functions are presented. The special features of these representations due to the compactness and curvature are analysed. Basic results of the theory of Lie algebras and Lie groups used in the main text are presented

Bayesian dynamic mediation analysis.

Science.gov (United States)

Huang, Jing; Yuan, Ying

2017-12-01

Most existing methods for mediation analysis assume that mediation is a stationary, time-invariant process, which overlooks the inherently dynamic nature of many human psychological processes and behavioral activities. In this article, we consider mediation as a dynamic process that continuously changes over time. We propose Bayesian multilevel time-varying coefficient models to describe and estimate such dynamic mediation effects. By taking the nonparametric penalized spline approach, the proposed method is flexible and able to accommodate any shape of the relationship between time and mediation effects. Simulation studies show that the proposed method works well and faithfully reflects the true nature of the mediation process. By modeling mediation effect nonparametrically as a continuous function of time, our method provides a valuable tool to help researchers obtain a more complete understanding of the dynamic nature of the mediation process underlying psychological and behavioral phenomena. We also briefly discuss an alternative approach of using dynamic autoregressive mediation model to estimate the dynamic mediation effect. The computer code is provided to implement the proposed Bayesian dynamic mediation analysis. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Dynamical networks of influence in small group discussions.

Science.gov (United States)

Moussaïd, Mehdi; Noriega Campero, Alejandro; Almaatouq, Abdullah

2018-01-01

In many domains of life, business and management, numerous problems are addressed by small groups of individuals engaged in face-to-face discussions. While research in social psychology has a long history of studying the determinants of small group performances, the internal dynamics that govern a group discussion are not yet well understood. Here, we rely on computational methods based on network analyses and opinion dynamics to describe how individuals influence each other during a group discussion. We consider the situation in which a small group of three individuals engages in a discussion to solve an estimation task. We propose a model describing how group members gradually influence each other and revise their judgments over the course of the discussion. The main component of the model is an influence network-a weighted, directed graph that determines the extent to which individuals influence each other during the discussion. In simulations, we first study the optimal structure of the influence network that yields the best group performances. Then, we implement a social learning process by which individuals adapt to the past performance of their peers, thereby affecting the structure of the influence network in the long run. We explore the mechanisms underlying the emergence of efficient or maladaptive networks and show that the influence network can converge towards the optimal one, but only when individuals exhibit a social discounting bias by downgrading the relative performances of their peers. Finally, we find a late-speaker effect, whereby individuals who speak later in the discussion are perceived more positively in the long run and are thus more influential. The numerous predictions of the model can serve as a basis for future experiments, and this work opens research on small group discussion to computational social sciences.

Training Vocational Rehabilitation Counselors in Group Dynamics: A Psychoeducational Model.

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Elliott, Timothy R.

1990-01-01

Describes a six-session psychoeducational program for training vocational rehabilitation counselors in group dynamics. Presents evaluation of program by counselors (N=15) in which leadership styles, conflict management, and typology of group tasks concepts were rated as most beneficial. (Author/ABL)

Multidimensional Recurrence Quantification Analysis (MdRQA) for the Analysis of Multidimensional Time-Series: A Software Implementation in MATLAB and Its Application to Group-Level Data in Joint Action.

Science.gov (United States)

Wallot, Sebastian; Roepstorff, Andreas; Mønster, Dan

2016-01-01

We introduce Multidimensional Recurrence Quantification Analysis (MdRQA) as a tool to analyze multidimensional time-series data. We show how MdRQA can be used to capture the dynamics of high-dimensional signals, and how MdRQA can be used to assess coupling between two or more variables. In particular, we describe applications of the method in research on joint and collective action, as it provides a coherent analysis framework to systematically investigate dynamics at different group levels-from individual dynamics, to dyadic dynamics, up to global group-level of arbitrary size. The Appendix in Supplementary Material contains a software implementation in MATLAB to calculate MdRQA measures.

Bottlenose dolphin Tursiops truncatus group dynamics, site fidelity ...

African Journals Online (AJOL)

... ecology in these waters. Photo-identification undertaken during systematic, non-systematic and opportunistic surveys conducted between 2001 and 2012 was used to assess group dynamics, site fidelity, residency and movement patterns of bottlenose dolphins in the archipelago. Three different patterns of residency were ...

Dynamic Incentives in Microfinance Group Lending

Directory of Open Access Journals (Sweden)

Naveen Kumar K

2012-04-01

Full Text Available One of the most essential tools of poverty reduction would be the viable expansion of institutional credit facilities to large sections of the people who neither have adequate collateral nor credit history to secure a loan. In this backdrop, social collateral is popularized through the group lending programs to address the credit market problems. Microfinance through group lending is acting as a screening device; the joint liability mechanism creates incentives for internal monitoring. Hence, it has received a lot of attention from policy makers as well as academicians. It is playing an important role in delivering financial services to the “socially and economically excluded” poor, in general, and women, in particular. The group lending works with various dynamic incentives. One such kind is principle of progressive lending and it plays a vital role in sustaining the groups for the persistent delivery of microfinance services to its members. In progressive lending, a typical borrower receives very small amounts at first, which increases with good repayment conduct or it links new, larger loans to past repayment. This article explores possible theoretical and empirical relationship between progressive lending and its determinants in group lending approach. The primary survey was conducted in 10 villages covering 106 self-help groups and 318 members in Karnataka, India. The empirical results show the progressive lending amount rising up to 698% of the initial loan of the self-help groups.

The Dynamics of the Local Group in the Era of Precision Astrometry

Science.gov (United States)

Besla, Gurtina; Garavito-Camargo, Nicolas; Patel, Ekta

2018-06-01

Our understanding of the dynamics of our Local Group of galaxies has changed dramatically over the past few years owing to significant advancements in astrometry and our theoretical understanding of galaxy structure. New surveys now enable us to map the 3D structure of our Milky Way and the dynamics of tracers of its dark matter distribution, like globular clusters, satellite galaxies and streams, with unprecedented precision. Some results have met with controversy, challenging preconceived notions of the orbital dynamics of key components of the Local Group. I will provide an overview of this evolving picture of our Local Group and outline how we can test the cold dark matter paradigm in the era of Gaia, LSST and JWST.

Emergence of grouping in multi-resource minority game dynamics

Science.gov (United States)

Huang, Zi-Gang; Zhang, Ji-Qiang; Dong, Jia-Qi; Huang, Liang; Lai, Ying-Cheng

2012-10-01

Complex systems arising in a modern society typically have many resources and strategies available for their dynamical evolutions. To explore quantitatively the behaviors of such systems, we propose a class of models to investigate Minority Game (MG) dynamics with multiple strategies. In particular, agents tend to choose the least used strategies based on available local information. A striking finding is the emergence of grouping states defined in terms of distinct strategies. We develop an analytic theory based on the mean-field framework to understand the ``bifurcations'' of the grouping states. The grouping phenomenon has also been identified in the Shanghai Stock-Market system, and we discuss its prevalence in other real-world systems. Our work demonstrates that complex systems obeying the MG rules can spontaneously self-organize themselves into certain divided states, and our model represents a basic and general mathematical framework to address this kind of phenomena in social, economical and political systems.

Annual activity report of Ignalina NPP Safety Analysis Group for 1996 year

International Nuclear Information System (INIS)

Ushpuras, E.; Augutis, J.; Bubelis, E.

1997-03-01

The main results of Ignalina NPP Safety Analysis Group (ISAG) investigations for 1996 are presented. ISAG is concentrating its research activities into four areas: the neutrons dynamics modelling, simulation of transient processes during loss of coolant accident, the reactor cooling systems modelling and the probabilistic safety assessment of accident confinement system. Ignalina Safety Analysis Report was prepared on the basis of these results. 37 refs., 9 tabs., 96 figs

The positive group affect spiral : a dynamic model of the emergence of positive affective similarity in work groups

NARCIS (Netherlands)

Walter, F.; Bruch, H.

This conceptual paper seeks to clarify the process of the emergence of positive collective affect. Specifically, it develops a dynamic model of the emergence of positive affective similarity in work groups. It is suggested that positive group affective similarity and within-group relationship

The maximal kinematical invariance group of fluid dynamics and explosion-implosion duality

International Nuclear Information System (INIS)

O'Raifeartaigh, L.; Sreedhar, V.V.

2001-01-01

It has recently been found that supernova explosions can be simulated in the laboratory by implosions induced in a plasma by intense lasers. A theoretical explanation is that the inversion transformation, (Σ:t→-1/t, x→x/t), leaves the Euler equations of fluid dynamics, with standard polytropic exponent, invariant. This implies that the kinematical invariance group of the Euler equations is larger than the Galilei group. In this paper we determine, in a systematic manner, the maximal invariance group G of general fluid dynamics and show that it is a semi-direct product G=SL(2, R) three G, where the SL(2, R) group contains the time-translations, dilations, and the inversion Σ, and G is the static (nine-parameter) Galilei group. A subtle aspect of the inclusion of viscosity fields is discussed and it is shown that the Navier-Stokes assumption of constant viscosity breaks the SL(2, R) group to a two-parameter group of time translations and dilations in a tensorial way. The 12-parameter group G is also known to be the maximal invariance group of the free Schroedinger equation. It originates in the free Hamilton-Jacobi equation which is central to both fluid dynamics and the Schroedinger equation

Facebook Groups as a Powerful and Dynamic Tool in Medical Education: Mixed-Method Study.

Science.gov (United States)

Nicolai, Leo; Schmidbauer, Moritz; Gradel, Maximilian; Ferch, Sabine; Antón, Sofía; Hoppe, Boj; Pander, Tanja; von der Borch, Philip; Pinilla, Severin; Fischer, Martin; Dimitriadis, Konstantinos

2017-12-22

Social networking sites, in particular Facebook, are not only predominant in students' social life but are to varying degrees interwoven with the medical curriculum. Particularly, Facebook groups have been identified for their potential in higher education. However, there is a paucity of data on user types, content, and dynamics of study-related Facebook groups. The aim of this study was to identify the role of study-related Facebook group use, characterize medical students that use or avoid using Facebook groups (demographics, participation pattern, and motivation), and analyze student posting behavior, covered topics, dynamics, and limitations in Facebook groups with regards to educational usage. Using a multi-method approach (interviews, focus groups, and qualitative and quantitative analysis of Facebook posts), we analyzed two representative Facebook groups of medical preclinical semesters at Ludwig-Maximilians-University (LMU) Munich. Facebook primary posts and replies over one semester were extracted and evaluated by using thematic content analysis. We developed and applied a coding scheme for studying the frequency and distribution of these posts. Additionally, we interviewed students with various degrees of involvement in the groups, as well as "new minorities," students not registered on Facebook. Facebook groups seem to have evolved as the main tool for medical students at LMU to complement the curriculum and to discuss study-related content. These Facebook groups are self-organizing and quickly adapt to organizational or subject-related challenges posed by the curriculum. A wide range of topics is covered, with a dominance of organization-related posts (58.35% [6916/11,853] of overall posts). By measuring reply rates and comments per category, we were able to identify learning tips and strategies, material sharing, and course content discussions as the most relevant categories. Rates of adequate replies in these categories ranged between 78% (11/14) and

Dynamic Group Management Scheme for Sustainable and Secure Information Sensing in IoT

Directory of Open Access Journals (Sweden)

Hyungjoo Kim

2016-10-01

Full Text Available The services provided to users in the environment associated with the Internet of Things (hereinafter referred to as IoT begin with the information collected from sensors. It is imperative to transmit high-quality sensor data for providing better services. It is also required to collect data only from those authenticated sensors. Moreover, it is imperative to collect high-quality data on a sustainable and continuous basis in order to provide services anytime and anywhere in the IoT environment. Therefore, high-quality, authenticated sensor networks should be constructed. The most prominent routing protocol to enhance the energy consumption efficiency for the sustainable data collection in a sensor network is the LEACH routing protocol. The LEACH routing protocol transmits sensor data by measuring the energy of sensors and allocating sensor groups dynamically. However, these sensor networks have vulnerabilities such as key leakage, eavesdropping, replay attack and relay attack, given the nature of wireless network communication. A large number of security techniques have been studied in order to solve these vulnerabilities. Nonetheless, these studies still cannot support the dynamic sensor group allocation of the LEACH routing protocol. Furthermore, they are not suitable for the sensor nodes whose hardware computing ability and energy resources are limited. Therefore, this paper proposed a group sensor communication protocol that utilizes only the four fundamental arithmetic operations and logical operation for the sensor node authentication and secure data transmission. Through the security analysis, this paper verified that the proposed scheme was secure to the vulnerabilities resulting from the nature of wireless network communication. Moreover, this paper verified through the performance analysis that the proposed scheme could be utilized efficiently.

Dynamic stiffness of pile groups in a multilayered soil. Part 1

International Nuclear Information System (INIS)

Ohta, Y.; Hijikata, K.; Kobayashi, Y.

1989-01-01

For evaluating the dynamic stiffness of the pile group foundations, forced vibration tests are executed on pile group foundation models. Two types of test models are used, one is a single pile model and the other a four-pile model. Dividing the tests into 4 steps, the forced vibration tests are performed. Step 1 is for the single pile model, and steps 2 to 4 are for the four-pile model. In step 2 and step 3, the gap effects between the foundation bottom and the ground surface are examined. In step 4, the backfill effects are obtained. Based on the test results, the pile group effects, the gap effects and the backfill effects on the dynamic characteristics of the pile group foundations are described in this paper

Nonequilibrium dynamical renormalization group: Dynamical crossover from weak to infinite randomness in the transverse-field Ising chain

Science.gov (United States)

Heyl, Markus; Vojta, Matthias

2015-09-01

In this work we formulate the nonequilibrium dynamical renormalization group (ndRG). The ndRG represents a general renormalization-group scheme for the analytical description of the real-time dynamics of complex quantum many-body systems. In particular, the ndRG incorporates time as an additional scale which turns out to be important for the description of the long-time dynamics. It can be applied to both translational-invariant and disordered systems. As a concrete application, we study the real-time dynamics after a quench between two quantum critical points of different universality classes. We achieve this by switching on weak disorder in a one-dimensional transverse-field Ising model initially prepared at its clean quantum critical point. By comparing to numerically exact simulations for large systems, we show that the ndRG is capable of analytically capturing the full crossover from weak to infinite randomness. We analytically study signatures of localization in both real space and Fock space.

Dynamic Network Logistic Regression: A Logistic Choice Analysis of Inter- and Intra-Group Blog Citation Dynamics in the 2004 US Presidential Election

Science.gov (United States)

2013-01-01

Methods for analysis of network dynamics have seen great progress in the past decade. This article shows how Dynamic Network Logistic Regression techniques (a special case of the Temporal Exponential Random Graph Models) can be used to implement decision theoretic models for network dynamics in a panel data context. We also provide practical heuristics for model building and assessment. We illustrate the power of these techniques by applying them to a dynamic blog network sampled during the 2004 US presidential election cycle. This is a particularly interesting case because it marks the debut of Internet-based media such as blogs and social networking web sites as institutionally recognized features of the American political landscape. Using a longitudinal sample of all Democratic National Convention/Republican National Convention–designated blog citation networks, we are able to test the influence of various strategic, institutional, and balance-theoretic mechanisms as well as exogenous factors such as seasonality and political events on the propensity of blogs to cite one another over time. Using a combination of deviance-based model selection criteria and simulation-based model adequacy tests, we identify the combination of processes that best characterizes the choice behavior of the contending blogs. PMID:24143060

Annual activity report of Ignalina NPP Safety Analysis Group for 1995 year

International Nuclear Information System (INIS)

Ushpuras, E.; Augutis, J.; Bubelis, E.

1995-01-01

The main results of Ignalina NPP Safety Analysis Group (ISAG) investigations for 1995 are presented. ISAG is concentrating its research activities into four areas: the neutrons dynamics modelling, simulation of transient processes during loss of coolant accident, the reactor cooling systems modelling and the probabilistic safety assessment of accident confinement system. 18 refs., 9 tabs., 110 figs

Annual activity report of Ignalina NPP Safety Analysis Group for 1994 year

International Nuclear Information System (INIS)

Ushpuras, E.; Kaliatka, A.; Chesna, B.; Dundulis, G.

1995-01-01

The main results of Ignalina NPP Safety Analysis Group (ISAG) investigations for 1994 are presented. ISAG is concentrated its research activities into 3 areas: the neutrons dynamics modeling, simulation of transient processes during loss of coolant accident and calculation of reactor building structure's streses and other mechanical properties in the case of accident. 6 refs., 13 tabs., 69 figs

Mutual Group Hypnosis: A Social Interaction Analysis.

Science.gov (United States)

Sanders, Shirley

Mutual Group Hypnosis is discussed in terms of its similarity to group dynamics in general and in terms of its similarity to a social interaction program (Role Modeling) designed to foster the expression of warmth and acceptance among group members. Hypnosis also fosters a regression to prelogical thought processes in the service of the ego. Group…

Dynamical glucometry: Use of multiscale entropy analysis in diabetes

Science.gov (United States)

Costa, Madalena D.; Henriques, Teresa; Munshi, Medha N.; Segal, Alissa R.; Goldberger, Ary L.

2014-09-01

Diabetes mellitus (DM) is one of the world's most prevalent medical conditions. Contemporary management focuses on lowering mean blood glucose values toward a normal range, but largely ignores the dynamics of glucose fluctuations. We probed analyte time series obtained from continuous glucose monitor (CGM) sensors. We show that the fluctuations in CGM values sampled every 5 min are not uncorrelated noise. Next, using multiscale entropy analysis, we quantified the complexity of the temporal structure of the CGM time series from a group of elderly subjects with type 2 DM and age-matched controls. We further probed the structure of these CGM time series using detrended fluctuation analysis. Our findings indicate that the dynamics of glucose fluctuations from control subjects are more complex than those of subjects with type 2 DM over time scales ranging from about 5 min to 5 h. These findings support consideration of a new framework, dynamical glucometry, to guide mechanistic research and to help assess and compare therapeutic interventions, which should enhance complexity of glucose fluctuations and not just lower mean and variance of blood glucose levels.

Statistical Analysis of Human Body Movement and Group Interactions in Response to Music

Science.gov (United States)

Desmet, Frank; Leman, Marc; Lesaffre, Micheline; de Bruyn, Leen

Quantification of time series that relate to physiological data is challenging for empirical music research. Up to now, most studies have focused on time-dependent responses of individual subjects in controlled environments. However, little is known about time-dependent responses of between-subject interactions in an ecological context. This paper provides new findings on the statistical analysis of group synchronicity in response to musical stimuli. Different statistical techniques were applied to time-dependent data obtained from an experiment on embodied listening in individual and group settings. Analysis of inter group synchronicity are described. Dynamic Time Warping (DTW) and Cross Correlation Function (CCF) were found to be valid methods to estimate group coherence of the resulting movements. It was found that synchronicity of movements between individuals (human-human interactions) increases significantly in the social context. Moreover, Analysis of Variance (ANOVA) revealed that the type of music is the predominant factor in both the individual and the social context.

Systems-Dynamic Analysis for Neighborhood Study

Science.gov (United States)

Systems-dynamic analysis (or system dynamics (SD)) helps planners identify interrelated impacts of transportation and land-use policies on neighborhood-scale economic outcomes for households and businesses, among other applications. This form of analysis can show benefits and tr...

Annual activity report of Ignalina NPP Safety Analysis Group for the year 1997

International Nuclear Information System (INIS)

Ushpuras, E.; Augutis, J.; Bubelis, E.; Kaliatka, A

1998-01-01

The main results of Ignalina NPP Safety Analysis Group (ISAG) investigations for the year 1997 are presented. ISAG is concentrating its research activities into four areas: the neutrons dynamics modelling, simulation of transient processes during loss of coolant accident, the reactor cooling systems modelling and the probabilistic safety assessment of accident confinement system

Relativized problems with abelian phase group in topological dynamics.

Science.gov (United States)

McMahon, D

1976-04-01

Let (X, T) be the equicontinuous minimal transformation group with X = pi(infinity)Z(2), the Cantor group, and S = [unk](infinity)Z(2) endowed with the discrete topology acting on X by right multiplication. For any countable group T we construct a function F:X x S --> T such that if (Y, T) is a minimal transformation group, then (X x Y, S) is a minimal transformation group with the action defined by (x, y)s = [xs, yF(x, s)]. If (W, T) is a minimal transformation group and varphi:(Y, T) --> (W, T) is a homomorphism, then identity x varphi:(X x Y, S) --> (X x W, S) is a homomorphism and has many of the same properties that varphi has. For this reason, one may assume that the phase group is abelian (or S) without loss of generality for many relativized problems in topological dynamics.

Group dynamics for the acquisition of competences in Project Management

Science.gov (United States)

Taguas, E. V.; Aguilar, M. C.; Castillo, C.; Polo, M. J.; Pérez, R.

2012-04-01

The Bologna Process promotes European citizens' employability from teaching fields in the University which implies the design of activities addressed to the development of skills for the labor market and engagement of employers. This work has been conceived for improving the formation of Engineering Project Management through group dynamics focused on: 1) the use of the creativity for solving problems; 2) promoting leadership capacities and social skills in multidisciplinary/multicultural work groups; 3) the ethical, social and environmental compromise; 4) the continuous learning. Different types of activities were designed: short activities of 15-30 minutes where fragments of books or songs are presented and discussed and long activities (2 h) where groups of students take different roles for solving common problems and situations within the Engineering Projects context. An electronic book with the content of the dynamics and the material for the students has been carried out. A sample of 20 students of Electronic Engineering degree which had participated at least in two dynamics, evaluated the utility for improving their formation in Engineering Project Management with a mark of 8.2 (scale 0-10, standard deviation equal to 0.9). On the other hand, the teachers observed how this type of work, promotes the interdisciplinary training and the acquisition of social skills, usually not-included in the objectives of the subjects.

Dynamical realizations of l-conformal Newton–Hooke group

International Nuclear Information System (INIS)

Galajinsky, Anton; Masterov, Ivan

2013-01-01

The method of nonlinear realizations and the technique previously developed in [A. Galajinsky, I. Masterov, Nucl. Phys. B 866 (2013) 212, (arXiv:1208.1403)] are used to construct a dynamical system without higher derivative terms, which holds invariant under the l-conformal Newton–Hooke group. A configuration space of the model involves coordinates, which parametrize a particle moving in d spatial dimensions and a conformal mode, which gives rise to an effective external field. The dynamical system describes a generalized multi-dimensional oscillator, which undergoes accelerated/decelerated motion in an ellipse in accord with evolution of the conformal mode. Higher derivative formulations are discussed as well. It is demonstrated that the multi-dimensional Pais–Uhlenbeck oscillator enjoys the l=3/2 -conformal Newton–Hooke symmetry for a particular choice of its frequencies

Dynamic Chest Image Analysis: Model-Based Perfusion Analysis in Dynamic Pulmonary Imaging

Directory of Open Access Journals (Sweden)

Kiuru Aaro

2003-01-01

Full Text Available The "Dynamic Chest Image Analysis" project aims to develop model-based computer analysis and visualization methods for showing focal and general abnormalities of lung ventilation and perfusion based on a sequence of digital chest fluoroscopy frames collected with the dynamic pulmonary imaging technique. We have proposed and evaluated a multiresolutional method with an explicit ventilation model for ventilation analysis. This paper presents a new model-based method for pulmonary perfusion analysis. According to perfusion properties, we first devise a novel mathematical function to form a perfusion model. A simple yet accurate approach is further introduced to extract cardiac systolic and diastolic phases from the heart, so that this cardiac information may be utilized to accelerate the perfusion analysis and improve its sensitivity in detecting pulmonary perfusion abnormalities. This makes perfusion analysis not only fast but also robust in computation; consequently, perfusion analysis becomes computationally feasible without using contrast media. Our clinical case studies with 52 patients show that this technique is effective for pulmonary embolism even without using contrast media, demonstrating consistent correlations with computed tomography (CT and nuclear medicine (NM studies. This fluoroscopical examination takes only about 2 seconds for perfusion study with only low radiation dose to patient, involving no preparation, no radioactive isotopes, and no contrast media.

Hydrogen bonding analysis of hydroxyl groups in glucose aqueous solutions by a molecular dynamics simulation study

International Nuclear Information System (INIS)

Chen, Cong; Li, Wei Zhong; Song, Yong Chen; Weng, Lin Dong; Zhang, Ning

2012-01-01

Molecular dynamics simulations have been performed to investigate hydrogen bonding characteristics of hydroxyl groups in glucose aqueous solutions with different concentrations. The hydrogen bonding abilities and strength of different O and H atom types have been calculated and compared. The acceptor/donor efficiencies have been predicted and it has been found that: (1) O2-HO2 and O3-HO3 are more efficient intramolecular hydrogen bonding acceptors than donors; (2) O1-HO1, O4-HO4 and O6-HO6 are more efficient intramolecular hydrogen bonding donors than acceptors; (5) O1-HO1 and O6-HO6 are more efficient intermolecular hydrogen bonding acceptors than donors while hydroxyl groups O2-HO2 and O4-HO4 are more efficient intermolecular hydrogen bonding donors than acceptors. The hydrogen bonding abilities of hydroxyl groups revealed that: (1) the hydrogen bonding ability of OH2-H w is larger than that of hydroxyl groups in glucose; (2) among the hydroxyl groups in glucose, the hydrogen bonding ability of O6-HO6 is the largest and the hydrogen bonding ability of O4-HO4 is the smallest; (3) the intermolecular hydrogen bonding ability of O6-HO6 is the largest; (4) the order for intramolecular hydrogen bonding abilities (from large to small) is O2-HO2, O1-HO1, O3-HO3, O6-HO6 and O4-HO4

Ignalina Safety Analysis Group

International Nuclear Information System (INIS)

Ushpuras, E.

1995-01-01

The article describes the fields of activities of Ignalina NPP Safety Analysis Group (ISAG) in the Lithuanian Energy Institute and overview the main achievements gained since the group establishment in 1992. The group is working under the following guidelines: in-depth analysis of the fundamental physical processes of RBMK-1500 reactors; collection, systematization and verification of the design and operational data; simulation and analysis of potential accident consequences; analysis of thermohydraulic and neutronic characteristics of the plant; provision of technical and scientific consultations to VATESI, Governmental authorities, and also international institutions, participating in various projects aiming at Ignalina NPP safety enhancement. The ISAG is performing broad scientific co-operation programs with both Eastern and Western scientific groups, supplying engineering assistance for Ignalina NPP. ISAG is also participating in the joint Lithuanian - Swedish - Russian project - Barselina, the first Probabilistic Safety Assessment (PSA) study of Ignalina NPP. The work is underway together with Maryland University (USA) for assessment of the accident confinement system for a range of breaks in the primary circuit. At present the ISAG personnel is also involved in the project under the grant from the Nuclear Safety Account, administered by the European Bank for reconstruction and development for the preparation and review of an in-depth safety assessment of the Ignalina plant

Joint symbolic dynamic analysis of cardiorespiratory interactions in patients on weaning trials.

Science.gov (United States)

Caminal, P; Giraldo, B; Zabaleta, H; Vallverdu, M; Benito, S; Ballesteros, D; Lopez-Rodriguez, L; Esteban, A; Baumert, M; Voss, A

2005-01-01

Assessing autonomic control provides information about patho-physiological imbalances. Measures of variability of the cardiac interbeat duration RR(n) and the variability of the breath duration TTot(n) are sensitive to those changes. The interactions between RR(n) and TTot(n) are complex and strongly non-linear. A study of joint symbolic dynamics is presented as a new short-term non-linear analysis method to investigate these interactions in patients on weaning trials. 78 patients from mechanical ventilation are studied: Group A (patients that failed to maintain spontaneous breathing and were reconnected) and Group B (patients with successful trials). Using the concept of joint symbolic dynamics, cardiac and respiratory changes were transformed into a word series, and the probability of occurrence of each word type was calculated and compared between both groups. Significant differences were found in 13 words, and the most significant pn(Wc010, r010): 0.0041 ± 0.0036 (group A) against 0.0012 ± 0.0024 (group B), p-value = 0.00001. The number of seldom occurring word types (forbidden words) also presents significant differences fwcr: 6.9 ± 6.6 against 13.5 ± 5.3, p-value = 0.00004. Joint symbolic dynamics provides an efficient non-linear representation of cardiorespiratory interactions that offers simple physiological interpretations.

Group theoretic reduction of Laplacian dynamical problems on fractal lattices

International Nuclear Information System (INIS)

Schwalm, W.A.; Schwalm, M.K.; Giona, M.

1997-01-01

Discrete forms of the Schroedinger equation, the diffusion equation, the linearized Landau-Ginzburg equation, and discrete models for vibrations and spin dynamics belong to a class of Laplacian-based finite difference models. Real-space renormalization of such models on finitely ramified regular fractals is known to give exact recursion relations. It is shown that these recursions commute with Lie groups representing continuous symmetries of the discrete models. Each such symmetry reduces the order of the renormalization recursions by one, resulting in a system of recursions with one fewer variable. Group trajectories are obtained from inverse images of fixed and invariant sets of the recursions. A subset of the Laplacian finite difference models can be mapped by change of boundary conditions and time dependence to a diffusion problem with closed boundaries. In such cases conservation of mass simplifies the group flow and obtaining the groups becomes easier. To illustrate this, the renormalization recursions for Green functions on four standard examples are decoupled. The examples are (1) the linear chain, (2) an anisotropic version of Dhar close-quote s 3-simplex, similar to a model dealt with by Hood and Southern, (3) the fourfold coordinated Sierpiacute nski lattice of Rammal and of Domany et al., and (4) a form of the Vicsek lattice. Prospects for applying the group theoretic method to more general dynamical systems are discussed. copyright 1997 The American Physical Society

Electronic [Re]Constitution of Groups: Group Dynamics from Face-to-Face to an Online Setting

Science.gov (United States)

Clouder, Lynn; Dalley, Jayne; Hargreaves, Julian; Parkes, Sally; Sellars, Julie; Toms, Jane

2006-01-01

The authors work as online tutors for a BSc (Hons) physiotherapy programme at Coventry University in the United Kingdom. This paper represents a stage in our developing understanding, over a 3 year period, of the impact of group dynamics on online interaction among physiotherapy students engaged in sharing with their peers their first experiences…

The walking behaviour of pedestrian social groups and its impact on crowd dynamics.

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Mehdi Moussaïd

Full Text Available Human crowd motion is mainly driven by self-organized processes based on local interactions among pedestrians. While most studies of crowd behaviour consider only interactions among isolated individuals, it turns out that up to 70% of people in a crowd are actually moving in groups, such as friends, couples, or families walking together. These groups constitute medium-scale aggregated structures and their impact on crowd dynamics is still largely unknown. In this work, we analyze the motion of approximately 1500 pedestrian groups under natural condition, and show that social interactions among group members generate typical group walking patterns that influence crowd dynamics. At low density, group members tend to walk side by side, forming a line perpendicular to the walking direction. As the density increases, however, the linear walking formation is bent forward, turning it into a V-like pattern. These spatial patterns can be well described by a model based on social communication between group members. We show that the V-like walking pattern facilitates social interactions within the group, but reduces the flow because of its "non-aerodynamic" shape. Therefore, when crowd density increases, the group organization results from a trade-off between walking faster and facilitating social exchange. These insights demonstrate that crowd dynamics is not only determined by physical constraints induced by other pedestrians and the environment, but also significantly by communicative, social interactions among individuals.

Dynamical renormalization group resummation of finite temperature infrared divergences

International Nuclear Information System (INIS)

Boyanovsky, D.; Vega, H.J. de; Boyanovsky, D.; Simionato, M.; Holman, R.; Simionato, M.

1999-01-01

We introduce the method of dynamical renormalization group to study relaxation and damping out of equilibrium directly in real time and apply it to the study of infrared divergences in scalar QED. This method allows a consistent resummation of infrared effects associated with the exchange of quasistatic transverse photons and leads to anomalous logarithmic relaxation of the form e -αampersandhthinsp;Tampersandhthinsp;tampersandhthinsp;ln[t/t 0 ] for hard momentum charged excitations. This is in contrast with the usual quasiparticle interpretation of charged collective excitations at finite temperature in the sense of exponential relaxation of a narrow width resonance for which the width is the imaginary part of the self-energy on shell. In the case of narrow resonances away from thresholds, this approach leads to the usual exponential relaxation. The hard thermal loop resummation program is incorporated consistently into the dynamical renormalization group yielding a picture of relaxation and damping phenomena in a plasma in real time that transcends the conceptual limitations of the quasiparticle picture and other types of resummation schemes. copyright 1999 The American Physical Society

Dynamic functional connectivity analysis reveals transient states of dysconnectivity in schizophrenia

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E. Damaraju

2014-01-01

Full Text Available Schizophrenia is a psychotic disorder characterized by functional dysconnectivity or abnormal integration between distant brain regions. Recent functional imaging studies have implicated large-scale thalamo-cortical connectivity as being disrupted in patients. However, observed connectivity differences in schizophrenia have been inconsistent between studies, with reports of hyperconnectivity and hypoconnectivity between the same brain regions. Using resting state eyes-closed functional imaging and independent component analysis on a multi-site data that included 151 schizophrenia patients and 163 age- and gender matched healthy controls, we decomposed the functional brain data into 100 components and identified 47 as functionally relevant intrinsic connectivity networks. We subsequently evaluated group differences in functional network connectivity, both in a static sense, computed as the pairwise Pearson correlations between the full network time courses (5.4 minutes in length, and a dynamic sense, computed using sliding windows (44 s in length and k-means clustering to characterize five discrete functional connectivity states. Static connectivity analysis revealed that compared to healthy controls, patients show significantly stronger connectivity, i.e., hyperconnectivity, between the thalamus and sensory networks (auditory, motor and visual, as well as reduced connectivity (hypoconnectivity between sensory networks from all modalities. Dynamic analysis suggests that (1, on average, schizophrenia patients spend much less time than healthy controls in states typified by strong, large-scale connectivity, and (2, that abnormal connectivity patterns are more pronounced during these connectivity states. In particular, states exhibiting cortical–subcortical antagonism (anti-correlations and strong positive connectivity between sensory networks are those that show the group differences of thalamic hyperconnectivity and sensory hypoconnectivity

Dynamical analysis of highly excited molecular spectra

Energy Technology Data Exchange (ETDEWEB)

Kellman, M.E. [Univ. of Oregon, Eugene (United States)

1993-12-01

The goal of this program is new methods for analysis of spectra and dynamics of highly excited vibrational states of molecules. In these systems, strong mode coupling and anharmonicity give rise to complicated classical dynamics, and make the simple normal modes analysis unsatisfactory. New methods of spectral analysis, pattern recognition, and assignment are sought using techniques of nonlinear dynamics including bifurcation theory, phase space classification, and quantization of phase space structures. The emphasis is chaotic systems and systems with many degrees of freedom.

Scenario development, qualitative causal analysis and system dynamics

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Michael H. Ruge

2009-02-01

Full Text Available The aim of this article is to demonstrate that technology assessments can be supported by methods such as scenario modeling and qualitative causal analysis. At Siemens, these techniques are used to develop preliminary purely qualitative models. These or parts of these comprehensive models may be extended to system dynamics models. While it is currently not possible to automatically generate a system dynamics models (or vice versa, obtain a qualitative simulation model from a system dynamics model, the two thechniques scenario development and qualitative causal analysis provide valuable indications on how to proceed towards a system dynamics model. For the qualitative analysis phase, the Siemens – proprietary prototype Computer – Aided Technology Assessment Software (CATS supportes complete cycle and submodel analysis. Keywords: Health care, telecommucations, qualitative model, sensitivity analysis, system dynamics.

New Frontiers in Analyzing Dynamic Group Interactions: Bridging Social and Computer Science.

Science.gov (United States)

Lehmann-Willenbrock, Nale; Hung, Hayley; Keyton, Joann

2017-10-01

This special issue on advancing interdisciplinary collaboration between computer scientists and social scientists documents the joint results of the international Lorentz workshop, "Interdisciplinary Insights into Group and Team Dynamics," which took place in Leiden, The Netherlands, July 2016. An equal number of scholars from social and computer science participated in the workshop and contributed to the papers included in this special issue. In this introduction, we first identify interaction dynamics as the core of group and team models and review how scholars in social and computer science have typically approached behavioral interactions in groups and teams. Next, we identify key challenges for interdisciplinary collaboration between social and computer scientists, and we provide an overview of the different articles in this special issue aimed at addressing these challenges.

Session 6: Dynamic Modeling and Systems Analysis

Science.gov (United States)

Csank, Jeffrey; Chapman, Jeffryes; May, Ryan

2013-01-01

These presentations cover some of the ongoing work in dynamic modeling and dynamic systems analysis. The first presentation discusses dynamic systems analysis and how to integrate dynamic performance information into the systems analysis. The ability to evaluate the dynamic performance of an engine design may allow tradeoffs between the dynamic performance and operability of a design resulting in a more efficient engine design. The second presentation discusses the Toolbox for Modeling and Analysis of Thermodynamic Systems (T-MATS). T-MATS is a Simulation system with a library containing the basic building blocks that can be used to create dynamic Thermodynamic Systems. Some of the key features include Turbo machinery components, such as turbines, compressors, etc., and basic control system blocks. T-MAT is written in the Matlab-Simulink environment and is open source software. The third presentation focuses on getting additional performance from the engine by allowing the limit regulators only to be active when a limit is danger of being violated. Typical aircraft engine control architecture is based on MINMAX scheme, which is designed to keep engine operating within prescribed mechanical/operational safety limits. Using a conditionally active min-max limit regulator scheme, additional performance can be gained by disabling non-relevant limit regulators

Analysis of Conceptualization Patterns across Groups of People

DEFF Research Database (Denmark)

Glückstad, Fumiko Kano; Herlau, Tue; Schmidt, Mikkel Nørgaard

2013-01-01

This paper analyzes patterns of conceptualizations possessed by different groups of subjects. The eventual goal of this work is to dynamically learn and structure semantic representations for groups of people sharing domain knowledge. In this paper, we conduct a survey for collecting data...

Dynamic Contingency Analysis Tool

Energy Technology Data Exchange (ETDEWEB)

2016-01-14

The Dynamic Contingency Analysis Tool (DCAT) is an open-platform and publicly available methodology to help develop applications that aim to improve the capabilities of power system planning engineers to assess the impact and likelihood of extreme contingencies and potential cascading events across their systems and interconnections. Outputs from the DCAT will help find mitigation solutions to reduce the risk of cascading outages in technically sound and effective ways. The current prototype DCAT implementation has been developed as a Python code that accesses the simulation functions of the Siemens PSS/E planning tool (PSS/E). It has the following features: It uses a hybrid dynamic and steady-state approach to simulating the cascading outage sequences that includes fast dynamic and slower steady-state events. It integrates dynamic models with protection scheme models for generation, transmission, and load. It models special protection systems (SPSs)/remedial action schemes (RASs) and automatic and manual corrective actions. Overall, the DCAT attempts to bridge multiple gaps in cascading-outage analysis in a single, unique prototype tool capable of automatically simulating and analyzing cascading sequences in real systems using multiprocessor computers.While the DCAT has been implemented using PSS/E in Phase I of the study, other commercial software packages with similar capabilities can be used within the DCAT framework.

Dynamic RCS Simulation of a Missile Target Group Based on the High-frequency Asymptotic Method

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Zhao Tao

2014-04-01

Full Text Available To simulate dynamic Radar Cross Section (RCS of missile target group, an efficient RCS prediction approach is proposed based on the high-frequency asymptotic theory. The minimal energy trajectory and coordinate transformation is used to get trajectories of the missile, decoys and roll booster, and establish the dynamic scene for the separate procedure of the target group, and the dynamic RCS including specular reflection, edge diffraction and multi-reflection from the target group are obtained by Physical Optics (PO, Equivalent Edge Currents (EEC and Shooting-and-Bouncing Ray (SBR methods. Compared with the dynamic RCS result with the common interpolation method, the proposed method is consistent with the common method when the targets in the scene are far away from each other and each target is not sheltered by others in the incident direction. When the target group is densely distributed and the shelter effect can not be neglected, the interpolation method is extremely difficult to realize, whereas the proposed method is successful.

BEYOND SOCIAL SKILLS: GROUP DYNAMICS AT SOCIAL SKILLS TRAINING FOR HIGH FUNCTIONING ADOLESCENTS WITH AUTISM SPECTRUM DISORDERS

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Agnieszka Siedler

2015-06-01

Full Text Available The usefulness of group social skills training in Autism Spectrum Disorder therapy has been well established. However, little is known about the group dynamics of this kind of intervention. The current multiple case studies were conducted to demonstrate that, despite of the functioning specifics of participants with ASD, processes associated with the dynamics of the group during group social skills training session may be noticeable. Intervention groups consisted of fifteen adolescents and preadolescents with high functioning Autism Spectrum Disorders aged between 11 to 17 years old divided into three training groups. The social skills training sessions were conducted on a weekly basis. The observation lasted for six months and it included the formation of the group, the period of stability and unexpected changes. After each group session, the therapists filled in a detailed report about the participants’ behavior and interactions between participants. Collected data were carefully analyzed for group dynamic features. It was noticed that adolescents participating in group interventions are susceptible to the influence of the group, take different individual roles and are moderately sensitive to changes in the group structure. The influence of the disorder characteristics on group dynamics was also observed. Although the results show that group dynamics can be observed at a group training for ASD, the need for further structured observation should be emphasized as a current study constituted the first approach to the subject.

Sensitivity analysis of complex models: Coping with dynamic and static inputs

International Nuclear Information System (INIS)

Anstett-Collin, F.; Goffart, J.; Mara, T.; Denis-Vidal, L.

2015-01-01

In this paper, we address the issue of conducting a sensitivity analysis of complex models with both static and dynamic uncertain inputs. While several approaches have been proposed to compute the sensitivity indices of the static inputs (i.e. parameters), the one of the dynamic inputs (i.e. stochastic fields) have been rarely addressed. For this purpose, we first treat each dynamic as a Gaussian process. Then, the truncated Karhunen–Loève expansion of each dynamic input is performed. Such an expansion allows to generate independent Gaussian processes from a finite number of independent random variables. Given that a dynamic input is represented by a finite number of random variables, its variance-based sensitivity index is defined by the sensitivity index of this group of variables. Besides, an efficient sampling-based strategy is described to estimate the first-order indices of all the input factors by only using two input samples. The approach is applied to a building energy model, in order to assess the impact of the uncertainties of the material properties (static inputs) and the weather data (dynamic inputs) on the energy performance of a real low energy consumption house. - Highlights: • Sensitivity analysis of models with uncertain static and dynamic inputs is performed. • Karhunen–Loève (KL) decomposition of the spatio/temporal inputs is performed. • The influence of the dynamic inputs is studied through the modes of the KL expansion. • The proposed approach is applied to a building energy model. • Impact of weather data and material properties on performance of real house is given

Palo Verde nuclear dynamic analysis (PANDA)

International Nuclear Information System (INIS)

Girjashankar, P.V.; Secker, P.A. Jr.; LeClair, S.J.; Mendoza, J.; Webb, J.R.

1988-01-01

Arizona Nuclear Power Project (ANPP) has initiated the development of a large scale dynamic analysis computer program for the Palo Verde Nuclear Generating Station (PVNGS). This paper presents the decision processes and preliminary development activities that have been pursued related to the code development. The PANDA (Palo Verde Nuclear Dynamic Analysis) code will be used for a variety of applications as described in this paper

Measuring Group Work Dynamics and Its Relation with L2 Learners' Task Motivation and Language Production

Science.gov (United States)

Poupore, Glen

2016-01-01

While learners of a second language (L2) are increasingly interacting in small groups as part of a communicative methodological paradigm, very few studies have investigated the social dynamics that occur in such groups. The aim of this study is to introduce a group work dynamic measuring instrument and to investigate the relationship between group…

[Various methods of dynamic functional analysis in human sciences and economics].

Science.gov (United States)

Schiltz, J

2006-01-01

Including the temporal and developmental dimension into the measurement of human conduct is a fundamental concern for those who do research in natural surroundings. Observing an individual day after day may possibly give a more complete vision of how behavior works than measuring a group of individuals at a single time and analyzing the differences found among them. Unfortunately most of the tools allowing analyzing individual time series call for large numbers of repeated observations. Thus, practicable longitudinal research designs often do not involve either enough repeated measurements for traditional time series analyses nor either replicate enough individuals for traditional, large-sample analyses. Dynamic factor analysis is a rationale and procedure for both pooling relatively short time series information across limited numbers of participants and analyzing the pooled information for its dynamic, process-relevant elements. It is a merging of two important analytical tools - multivariate time series and the common factor model, from which it distinguishes itself mainly by the fact that in dynamic factor analysis, the values of the common factors can influence the values of the observed variables both concurrently and in delayed fashion. Dynamic factor analysis is actually a method which allows detecting structures in the time series as well as the relations between the series and the explanatory variables. We illustrate the different models used in psychology and social sciences, as well as in econometry and economics.

Sex differences in in-group cooperation vary dynamically with competitive conditions and outcomes.

Science.gov (United States)

Bailey, Drew H; Winegard, Benjamin; Oxford, Jon; Geary, David C

2012-03-18

Men's but not women's investment in a public goods game varied dynamically with the presence or absence of a perceived out-group. Three hundred fifty-four (167 male) young adults participated in multiple iterations of a public goods game under intergroup and individual competition conditions. Participants received feedback about whether their investments in the group were sufficient to earn a bonus to be shared among all in-group members. Results for the first trial confirm previous research in which men's but not women's investments were higher when there was a competing out-group. We extended these findings by showing that men's investment in the in-group varied dynamically by condition depending on the outcome of the previous trial: In the group condition, men, but not women, decreased spending following a win (i.e., earning an in-group bonus). In the individual condition, men, but not women, increased spending following a win. We hypothesize that these patterns reflect a male bias to calibrate their level of in-group investment such that they sacrifice only what is necessary for their group to successfully compete against a rival group.

Sex Differences in In-Group Cooperation Vary Dynamically with Competitive Conditions and Outcomes

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Drew H. Bailey

2012-01-01

Full Text Available Men's but not women's investment in a public goods game varied dynamically with the presence or absence of a perceived out-group. Three hundred fifty-four (167 male young adults participated in multiple iterations of a public goods game under intergroup and individual competition conditions. Participants received feedback about whether their investments in the group were sufficient to earn a bonus to be shared among all in-group members. Results for the first trial confirm previous research in which men's but not women's investments were higher when there was a competing out-group. We extended these findings by showing that men's investment in the in-group varied dynamically by condition depending on the outcome of the previous trial: In the group condition, men, but not women, decreased spending following a win (i.e., earning an in-group bonus. In the individual condition, men, but not women, increased spending following a win. We hypothesize that these patterns reflect a male bias to calibrate their level of in-group investment such that they sacrifice only what is necessary for their group to successfully compete against a rival group.

Executives' speech expressiveness: analysis of perceptive and acoustic aspects of vocal dynamics.

Science.gov (United States)

Marquezin, Daniela Maria Santos Serrano; Viola, Izabel; Ghirardi, Ana Carolina de Assis Moura; Madureira, Sandra; Ferreira, Léslie Piccolotto

2015-01-01

To analyze speech expressiveness in a group of executives based on perceptive and acoustic aspects of vocal dynamics. Four male subjects participated in the research study (S1, S2, S3, and S4). The assessments included the Kingdomality test to obtain the keywords of communicative attitudes; perceptive-auditory assessment to characterize vocal quality and dynamics, performed by three judges who are speech language pathologists; perceptiveauditory assessment to judge the chosen keywords; speech acoustics to assess prosodic elements (Praat software); and a statistical analysis. According to the perceptive-auditory analysis of vocal dynamics, S1, S2, S3, and S4 did not show vocal alterations and all of them were considered with lowered habitual pitch. S1: pointed out as insecure, nonobjective, nonempathetic, and unconvincing with inappropriate use of pauses that are mainly formed by hesitations; inadequate separation of prosodic groups with breaking of syntagmatic constituents. S2: regular use of pauses for respiratory reload, organization of sentences, and emphasis, which is considered secure, little objective, empathetic, and convincing. S3: pointed out as secure, objective, empathetic, and convincing with regular use of pauses for respiratory reload and organization of sentences and hesitations. S4: the most secure, objective, empathetic, and convincing, with proper use of pauses for respiratory reload, planning, and emphasis; prosodic groups agreed with the statement, without separating the syntagmatic constituents. The speech characteristics and communicative attitudes were highlighted in two subjects in a different manner, in such a way that the slow rate of speech and breaks of the prosodic groups transmitted insecurity, little objectivity, and nonpersuasion.

Detecting concealed information from groups using a dynamic questioning approach: simultaneous skin conductance measurement and immediate feedback

Directory of Open Access Journals (Sweden)

Ewout H Meijer

2013-02-01

Full Text Available Lie detection procedures typically aim at determining the guilt or innocence of a single suspect. The Concealed Information Test (CIT, for example, has been shown to be highly successful in detecting the presence or absence of crime-related information in a suspect’s memory. Many of today’s security threats, however, do not come from individuals, but from organized groups such as criminal organizations or terrorist networks. In this study, we tested whether a plan of an upcoming mock terrorist attack could be extracted from a group of suspects using a dynamic questioning approach. One-hundred participants were tested in 20 groups of 5. Each group was asked to plan a mock terrorist attack based on a list of potential countries, cities and streets. Next, three questions referring to the country, city, and street were presented, each with 5 options. Skin conductance in all 5 members of the group was measured simultaneously during this presentation. The dynamic questioning approach entailed direct analysis of the data, and if the average skin conductance of the group to a certain option exceeded a threshold, this option was followed up. E.g., if the reaction to the option ‘Italy’ exceeded the threshold, this was followed up by presenting 5 cities in Italy. Results showed that in 19 of the 20 groups the country was correctly detected using this procedure. In 13 of these remaining 19 groups the city was correctly detected. In 7 of these 13, the street was also correctly detected. The question about the country resulted in no false positives (out of 20, the question about the city resulted in 2 false positives (out of 19, while the question about the streets resulted in 2 false positives (out of 13. Furthermore, the 2 false positives at the city level also yielded a false positive at the street level. Taken together these results indicate our dynamic questioning approach can help to unveil plans about a mock terrorist attack.

Static Analysis of Dynamic Languages

DEFF Research Database (Denmark)

Madsen, Magnus

Dynamic programming languages are highly popular and widely used. Java- Script is often called the lingua franca of the web and it is the de facto standard for client-side web programming. On the server-side the PHP, Python and Ruby languages are prevalent. What these languages have in common...... with static type systems, such as Java and C# , but the same features are rarely available for dynamic languages such as JavaScript. The aim of this thesis is to investigate techniques for improving the tool- support for dynamic programming languages without imposing any artificial restrictions...... of new dataflow analysis techniques to tackle the nature of dynamic programming languages....

Dynamical groups of a particle in a periodic potential

International Nuclear Information System (INIS)

Yusuf, M.

1992-09-01

Solving the Schroedinger non-relativistic equation of a particle moving under the influence of the potential V(θ) = ω(1 - cosθ) leads to us to the standard Mathieu equation. Jahnke-Emde's(1938), the periodic solutions are Mathieu functions of even order. With an approximation we study two important limiting cases, a simple quantum rotator and one-dimensional linear oscillator. We show the dynamical groups of these special, and a further study of the real problem connects us an Euclidean group of 2D. An IRR of matrix elements give us the energy levels. The interface between the E 2 and Bessel Functions is showed. (author). 7 refs

Information behavior in dynamic group work contexts

DEFF Research Database (Denmark)

Sonnenwald, Diane H.; Pierce, Linda G.

2000-01-01

personnel and documentation on C2. During data analysis, three important themes that highlight the why, what, how and consequences of information behavior in C2 emerged. The first is the concept of interwoven situational awareness consisting of individual, intragroup and intergroup shared understanding...... of the situation. Interwoven situational awareness appears to facilitate response to dynamic, constraint-bound situations. The second theme describes the need for dense social networks or frequent communication between participants about the work context and situation, the work process and domain...

Prime implicants in dynamic reliability analysis

International Nuclear Information System (INIS)

Tyrväinen, Tero

2016-01-01

This paper develops an improved definition of a prime implicant for the needs of dynamic reliability analysis. Reliability analyses often aim to identify minimal cut sets or prime implicants, which are minimal conditions that cause an undesired top event, such as a system's failure. Dynamic reliability analysis methods take the time-dependent behaviour of a system into account. This means that the state of a component can change in the analysed time frame and prime implicants can include the failure of a component at different time points. There can also be dynamic constraints on a component's behaviour. For example, a component can be non-repairable in the given time frame. If a non-repairable component needs to be failed at a certain time point to cause the top event, we consider that the condition that it is failed at the latest possible time point is minimal, and the condition in which it fails earlier non-minimal. The traditional definition of a prime implicant does not account for this type of time-related minimality. In this paper, a new definition is introduced and illustrated using a dynamic flowgraph methodology model. - Highlights: • A new definition of a prime implicant is developed for dynamic reliability analysis. • The new definition takes time-related minimality into account. • The new definition is needed in dynamic flowgraph methodology. • Results can be represented by a smaller number of prime implicants.

Do Dental Students' Personality Types and Group Dynamics Affect Their Performance in Problem-Based Learning?

Science.gov (United States)

Ihm, Jung-Joon; An, So-Youn; Seo, Deog-Gyu

2017-06-01

The aim of this study was to determine whether the personality types of dental students and their group dynamics were linked to their problem-based learning (PBL) performance. The Myers-Briggs Type Indicator (MBTI) instrument was used with 263 dental students enrolled in Seoul National University School of Dentistry from 2011 to 2013; the students had participated in PBL in their first year. A four-session PBL setting was designed to analyze how individual personality types and the diversity of their small groups were associated with PBL performance. Overall, the results showed that the personality type of PBL performance that was the most prominent was Judging. As a group became more diverse with its different constituent personality characteristics, there was a tendency for the group to be higher ranked in terms of PBL performance. In particular, the overperforming group was clustered around three major profiles: Extraverted Intuitive Thinking Judging (ENTJ), Introverted Sensing Thinking Judging (ISTJ), and Extraverted Sensing Thinking Judging (ESTJ). Personality analysis would be beneficial for dental faculty members in order for them to understand the extent to which cooperative learning would work smoothly, especially when considering group personalities.

Group Dynamics and Individual Roles: A Differentiated Approach to Social-Emotional Learning

Science.gov (United States)

Dugas, Daryl

2017-01-01

Differentiated instruction is a set of strategies to help teachers meet each child where he or she is in order to improve students' engagement, lead them to do their best work, and maximize their success. This article describes a differentiated classroom management approach based in group dynamics which focuses on the development of group norms…

Dynamic Event Tree Analysis Through RAVEN

Energy Technology Data Exchange (ETDEWEB)

A. Alfonsi; C. Rabiti; D. Mandelli; J. Cogliati; R. A. Kinoshita; A. Naviglio

2013-09-01

Conventional Event-Tree (ET) based methodologies are extensively used as tools to perform reliability and safety assessment of complex and critical engineering systems. One of the disadvantages of these methods is that timing/sequencing of events and system dynamics is not explicitly accounted for in the analysis. In order to overcome these limitations several techniques, also know as Dynamic Probabilistic Risk Assessment (D-PRA), have been developed. Monte-Carlo (MC) and Dynamic Event Tree (DET) are two of the most widely used D-PRA methodologies to perform safety assessment of Nuclear Power Plants (NPP). In the past two years, the Idaho National Laboratory (INL) has developed its own tool to perform Dynamic PRA: RAVEN (Reactor Analysis and Virtual control ENvironment). RAVEN has been designed in a high modular and pluggable way in order to enable easy integration of different programming languages (i.e., C++, Python) and coupling with other application including the ones based on the MOOSE framework, developed by INL as well. RAVEN performs two main tasks: 1) control logic driver for the new Thermo-Hydraulic code RELAP-7 and 2) post-processing tool. In the first task, RAVEN acts as a deterministic controller in which the set of control logic laws (user defined) monitors the RELAP-7 simulation and controls the activation of specific systems. Moreover, RAVEN also models stochastic events, such as components failures, and performs uncertainty quantification. Such stochastic modeling is employed by using both MC and DET algorithms. In the second task, RAVEN processes the large amount of data generated by RELAP-7 using data-mining based algorithms. This paper focuses on the first task and shows how it is possible to perform the analysis of dynamic stochastic systems using the newly developed RAVEN DET capability. As an example, the Dynamic PRA analysis, using Dynamic Event Tree, of a simplified pressurized water reactor for a Station Black-Out scenario is presented.

Understanding dynamics using sensitivity analysis: caveat and solution

Science.gov (United States)

2011-01-01

Background Parametric sensitivity analysis (PSA) has become one of the most commonly used tools in computational systems biology, in which the sensitivity coefficients are used to study the parametric dependence of biological models. As many of these models describe dynamical behaviour of biological systems, the PSA has subsequently been used to elucidate important cellular processes that regulate this dynamics. However, in this paper, we show that the PSA coefficients are not suitable in inferring the mechanisms by which dynamical behaviour arises and in fact it can even lead to incorrect conclusions. Results A careful interpretation of parametric perturbations used in the PSA is presented here to explain the issue of using this analysis in inferring dynamics. In short, the PSA coefficients quantify the integrated change in the system behaviour due to persistent parametric perturbations, and thus the dynamical information of when a parameter perturbation matters is lost. To get around this issue, we present a new sensitivity analysis based on impulse perturbations on system parameters, which is named impulse parametric sensitivity analysis (iPSA). The inability of PSA and the efficacy of iPSA in revealing mechanistic information of a dynamical system are illustrated using two examples involving switch activation. Conclusions The interpretation of the PSA coefficients of dynamical systems should take into account the persistent nature of parametric perturbations involved in the derivation of this analysis. The application of PSA to identify the controlling mechanism of dynamical behaviour can be misleading. By using impulse perturbations, introduced at different times, the iPSA provides the necessary information to understand how dynamics is achieved, i.e. which parameters are essential and when they become important. PMID:21406095

Group unconscious common orientation: exploratory study at the Basque Foundation for the investigation of mental health group training for therapists

CERN Document Server

Trojaola Zapirain, Begona; Carminati, Federico; Gonzalez Torres, Miguel Angel; Gonzalez de Mendivil, Ernesto; Fouassier, Claire; Gex-Fabry, Marianne; Martin, Francois; Labarere, Jose; Demongeot, Jacques; Lorincz, Erika Nora

2014-01-01

Group phenomena have been used since antiquity in therapeutic, social, economic and political domains. According to Bion, the interactions between group members generate a ``group unconscious'' and its behavior is governed and oriented by Bion's ``basic assumptions.'' The present work has been conducted during group analysis training at the Basque Foundation for the Investigation of Mental Health (OMIE) at Bilbao, consisting of eleven sessions. The participants are presented with an ``absurd questionnaire'' proposing 50 pairs of images, in each of which one image has to be chosen. The results are used to search for evidence in favor of the influence of group dynamics on individual choices of the images proposed in the questionnaire. Our analysis finds some evidence for an effect of group dynamics both on the initial choice of the pictures and on the evolution of the number of changes (swaps) of picture choices across the eleven sessions. We interpret these effects in the light of Bion's view of group dynamics...

COSTANZA, 1-D 2 Group Space-Dependent Reactor Dynamics of Spatial Reactor with 1 Group Delayed Neutrons

International Nuclear Information System (INIS)

Agazzi, A.; Gavazzi, C.; Vincenti, E.; Monterosso, R.

1964-01-01

1 - Nature of physical problem solved: The programme studies the spatial dynamics of reactor TESI, in the two group and one space dimension approximation. Only one group of delayed neutrons is considered. The programme simulates the vertical movement of the control rods according to any given movement law. The programme calculates the evolution of the fluxes and temperature and precursor concentration in space and time during the power excursion. 2 - Restrictions on the complexity of the problem: The maximum number of lattice points is 100

Enabling dynamics in face analysis

NARCIS (Netherlands)

Dibeklioğlu, H.

2014-01-01

Most of the approaches in automatic face analysis rely solely on static appearance. However, temporal analysis of expressions reveals interesting patterns. For a better understanding of the human face, this thesis focuses on temporal changes in the face, and dynamic patterns of expressions. In

Dynamic Group Diffie-Hellman Key Exchange under standard assumptions

International Nuclear Information System (INIS)

Bresson, Emmanuel; Chevassut, Olivier; Pointcheval, David

2002-01-01

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

Harmonic Analysis and Group Representation

CERN Document Server

Figa-Talamanca, Alessandro

2011-01-01

This title includes: Lectures - A. Auslander, R. Tolimeri - Nilpotent groups and abelian varieties, M Cowling - Unitary and uniformly bounded representations of some simple Lie groups, M. Duflo - Construction de representations unitaires d'un groupe de Lie, R. Howe - On a notion of rank for unitary representations of the classical groups, V.S. Varadarajan - Eigenfunction expansions of semisimple Lie groups, and R. Zimmer - Ergodic theory, group representations and rigidity; and, Seminars - A. Koranyi - Some applications of Gelfand pairs in classical analysis.

Positive Nonlinear Dynamical Group Uniting Quantum Mechanics and Thermodynamics

OpenAIRE

Beretta, Gian Paolo

2006-01-01

We discuss and motivate the form of the generator of a nonlinear quantum dynamical group 'designed' so as to accomplish a unification of quantum mechanics (QM) and thermodynamics. We call this nonrelativistic theory Quantum Thermodynamics (QT). Its conceptual foundations differ from those of (von Neumann) quantum statistical mechanics (QSM) and (Jaynes) quantum information theory (QIT), but for thermodynamic equilibrium (TE) states it reduces to the same mathematics, and for zero entropy stat...

Analysis of dynamic multiplicity fluctuations at PHOBOS

Science.gov (United States)

Chai, Zhengwei; PHOBOS Collaboration; Back, B. B.; Baker, M. D.; Ballintijn, M.; Barton, D. S.; Betts, R. R.; Bickley, A. A.; Bindel, R.; Budzanowski, A.; Busza, W.; Carroll, A.; Chai, Z.; Decowski, M. P.; García, E.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Heintzelman, G. A.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Holynski, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Katzy, J.; Khan, N.; Kucewicz, W.; Kulinich, P.; Kuo, C. M.; Lin, W. T.; Manly, S.; McLeod, D.; Mignerey, A. C.; Nouicer, R.; Olszewski, A.; Pak, R.; Park, I. C.; Pernegger, H.; Reed, C.; Remsberg, L. P.; Reuter, M.; Roland, C.; Roland, G.; Rosenberg, L.; Sagerer, J.; Sarin, P.; Sawicki, P.; Skulski, W.; Steinberg, P.; Stephans, G. S. F.; Sukhanov, A.; Tang, J. L.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Verdier, R.; Wolfs, F. L. H.; Wosiek, B.; Wozniak, K.; Wuosmaa, A. H.; Wyslouch, B.

2005-01-01

This paper presents the analysis of the dynamic fluctuations in the inclusive charged particle multiplicity measured by PHOBOS for Au+Au collisions at surdsNN = 200GeV within the pseudo-rapidity range of -3 < η < 3. First the definition of the fluctuations observables used in this analysis is presented, together with the discussion of their physics meaning. Then the procedure for the extraction of dynamic fluctuations is described. Some preliminary results are included to illustrate the correlation features of the fluctuation observable. New dynamic fluctuations results will be available in a later publication.

the use of the dynamic magnification factor in the dynamic analysis

African Journals Online (AJOL)

Uncle Greg 4 Real

bridges and some country's codes of practice made specifications in respect of the dynamic magnification factor for the analysis and design of various types of structures subjected to ... span. For example the United kingdom code. [10] presented dynamic magnification factors, related ... For SDOF (Single Degree of Freedom).

Renormalization group method in the theory of dynamical systems

International Nuclear Information System (INIS)

Sinai, Y.G.; Khanin, K.M.

1988-01-01

One of the most important events in the theory of dynamical systems for the last decade has become a wide penetration of ideas and renormalization group methods (RG) into this traditional field of mathematical physics. RG-method has been one of the main tools in statistical physics and it has proved to be rather effective while solving problems of the theory of dynamical systems referring to new types of bifurcations (see further). As in statistical mechanics the application of the RG-method is of great interest in the neighborhood of the critical point concerning the order-chaos transition. First the RG-method was applied in the pioneering papers dedicated to the appearance of a stochastical regime as a result of infinite sequences of period doubling bifurcations. At present this stochasticity mechanism is the most studied one and many papers deal with it. The study of the so-called intermittency phenomenon was the next example of application of the RG-method, i.e. the study of such a situation where the domains of the stochastical and regular behavior do alternate along a trajectory of the dynamical system

Dynamic stimulated Brillouin scattering analysis

DEFF Research Database (Denmark)

Djupsöbacka, A.; Jacobsen, Gunnar; Tromborg, Bjarne

2000-01-01

We present a new simple analysis - including the effect of spontaneous emission - of the (dynamic) influence of SBS on the detected receiver eye diagram. It applies in principle for general types of modulation formats such as the digital formats of ASK, FSK, and PSK. The analysis is formulated fo...

Dynamics of safety performance and culture: a group model building approach.

Science.gov (United States)

Goh, Yang Miang; Love, Peter E D; Stagbouer, Greg; Annesley, Chris

2012-09-01

The management of occupational health and safety (OHS) including safety culture interventions is comprised of complex problems that are often hard to scope and define. Due to the dynamic nature and complexity of OHS management, the concept of system dynamics (SD) is used to analyze accident prevention. In this paper, a system dynamics group model building (GMB) approach is used to create a causal loop diagram of the underlying factors influencing the OHS performance of a major drilling and mining contractor in Australia. While the organization has invested considerable resources into OHS their disabling injury frequency rate (DIFR) has not been decreasing. With this in mind, rich individualistic knowledge about the dynamics influencing the DIFR was acquired from experienced employees with operations, health and safety and training background using a GMB workshop. Findings derived from the workshop were used to develop a series of causal loop diagrams that includes a wide range of dynamics that can assist in better understanding the causal influences OHS performance. The causal loop diagram provides a tool for organizations to hypothesize the dynamics influencing effectiveness of OHS management, particularly the impact on DIFR. In addition the paper demonstrates that the SD GMB approach has significant potential in understanding and improving OHS management. Copyright © 2011 Elsevier Ltd. All rights reserved.

Robustness and Vulnerability of Networks with Dynamical Dependency Groups.

Science.gov (United States)

Bai, Ya-Nan; Huang, Ning; Wang, Lei; Wu, Zhi-Xi

2016-11-28

The dependency property and self-recovery of failure nodes both have great effects on the robustness of networks during the cascading process. Existing investigations focused mainly on the failure mechanism of static dependency groups without considering the time-dependency of interdependent nodes and the recovery mechanism in reality. In this study, we present an evolving network model consisting of failure mechanisms and a recovery mechanism to explore network robustness, where the dependency relations among nodes vary over time. Based on generating function techniques, we provide an analytical framework for random networks with arbitrary degree distribution. In particular, we theoretically find that an abrupt percolation transition exists corresponding to the dynamical dependency groups for a wide range of topologies after initial random removal. Moreover, when the abrupt transition point is above the failure threshold of dependency groups, the evolving network with the larger dependency groups is more vulnerable; when below it, the larger dependency groups make the network more robust. Numerical simulations employing the Erdős-Rényi network and Barabási-Albert scale free network are performed to validate our theoretical results.

Dynamic Path Analysis in Life-Course Epidemiology

DEFF Research Database (Denmark)

Gamborg, Michael Orland; Boje Jensen, Gorm; Sørensen, Thorkild I.A.

2011-01-01

it works through other risk factors. In this paper, the dynamic path analysis model is presented as a tool to analyze these dynamic mechanisms in life-course epidemiology. A key feature of dynamic path analysis is its ability to decompose the total effect of a risk factor into a direct effect (not mediated...... by other variables) and indirect effects (mediated through other variables). This is illustrated by examining the associations between repeated measurements of body mass index (BMI) and systolic blood pressure (SBP) and the risk of CHD in a sample of Danish men between 1976 and 2006. The effect of baseline...... BMI on the risk of CHD is decomposed into a direct effect and indirect effects going through later BMI, concurrent SBP, or later SBP. In conclusion, dynamic path analysis is a flexible tool that by the decomposition of effects can be used to increase the understanding of mechanisms that underlie...

Dynamics of group knowledge production in facilitated modelling workshops

DEFF Research Database (Denmark)

Tavella, Elena; Franco, L. Alberto

2015-01-01

by which models are jointly developed with group members interacting face-to-face, with or without computer support. The models produced are used to inform negotiations about the nature of the issues faced by the group, and how to address them. While the facilitated modelling literature is impressive......, the workshop. Drawing on the knowledge-perspective of group communication, we conducted a micro-level analysis of a transcript of a facilitated modelling workshop held with the management team of an Alternative Food Network in the UK. Our analysis suggests that facilitated modelling interactions can take...

Building consensus in strategic decision-making : system dynamics as a group support system

NARCIS (Netherlands)

Vennix, J.A.M.

1995-01-01

System dynamics was originally founded as a method for modeling and simulating the behavior of industrial systems. In recent years it is increasingly employed as a Group Support System for strategic decision-making groups. The model is constructed in direct interaction with a management team, and

41 CFR 60-2.12 - Job group analysis.

Science.gov (United States)

2010-07-01

... 41 Public Contracts and Property Management 1 2010-07-01 2010-07-01 true Job group analysis. 60-2... group analysis. (a) Purpose: A job group analysis is a method of combining job titles within the... employed. (b) In the job group analysis, jobs at the establishment with similar content, wage rates, and...

Social Network Analysis as an Analytic Tool for Task Group Research: A Case Study of an Interdisciplinary Community of Practice

Science.gov (United States)

Lockhart, Naorah C.

2017-01-01

Group counselors commonly collaborate in interdisciplinary settings in health care, substance abuse, and juvenile justice. Social network analysis is a methodology rarely used in counseling research yet has potential to examine task group dynamics in new ways. This case study explores the scholarly relationships among 36 members of an…

Condition-based dynamic maintenance operations planning and grouping. Application to commercial heavy vehicles

Energy Technology Data Exchange (ETDEWEB)

Bouvard, K., E-mail: keomany.bouvard@volvo.co [Volvo Technology, 99 route de Lyon, 69806 Saint Priest cedex (France); Laboratoire d' Automatique de Genie Informatique et Signal - FRE3303 - Polytech' Lille, 59655 Villeneuve d' Ascq (France); Artus, S., E-mail: samuel.artus@volvo.co [Volvo Technology, 99 route de Lyon, 69806 Saint Priest cedex (France); Berenguer, C., E-mail: christophe.berenguer@utt.f [Universite de technologie de Troyes - Institut Charles Delaunay and UMR CNRS 6279 - 12, rue Marie Curie, BP2060, 10010 Troyes cedex (France); Cocquempot, V., E-mail: vincent.cocquempot@univ-lille1.f [Laboratoire d' Automatique de Genie Informatique et Signal - FRE3303 - Polytech' Lille, 59655 Villeneuve d' Ascq (France)

2011-06-15

This paper aims at presenting a method to optimize the maintenance planning for a commercial heavy vehicle. Such a vehicle may be considered as a multi-components system. Grouping maintenance operations related to each component reduces the global maintenance cost of the system. Classically, the optimization problem is solved using a priori reliability characteristics of components. Two types of methods may be used, i.e. static or dynamic methods. Static methods provide a fixed maintenance planning, whereas dynamic methods redefine the groups of maintenance operations at each decision time. Dynamic procedures can incorporate component information such as component states or detected failures. For deteriorating systems, reliability characteristics of each component may be estimated thanks to deterioration models and may be updated when a degradation measure is available. This additional information on degradation features allows to better follow the real state of each component and to improve the maintenance planning.

Understanding the Influence of Organizational Culture and Group Dynamics on Organizational Change and Learning

Science.gov (United States)

Lucas, Colleen; Kline, Theresa

2008-01-01

Purpose: The purpose of this study is to investigate the relationship between organizational culture, group dynamics, and organizational learning in the context of organizational change. Design/methodology/approach: A case study was used to examine cultural and group level factors that potentially influence groups' learning in the context of…

Group Counseling with United States Racial Minority Groups: A 25-Year Content Analysis

Science.gov (United States)

Stark-Rose, Rose M.; Livingston-Sacin, Tina M.; Merchant, Niloufer; Finley, Amanda C.

2012-01-01

A 25-year content analysis was conducted of published group work articles that focused on 5 racial groups (African American, Asian American/Pacific Islander, Latino/a, Native American, and Intercultural group). Articles were included if they described an intervention or conceptual model with 1 of the racial groups. The analysis revealed 15 content…

Inferring gene expression dynamics via functional regression analysis

Directory of Open Access Journals (Sweden)

Leng Xiaoyan

2008-01-01

Full Text Available Abstract Background Temporal gene expression profiles characterize the time-dynamics of expression of specific genes and are increasingly collected in current gene expression experiments. In the analysis of experiments where gene expression is obtained over the life cycle, it is of interest to relate temporal patterns of gene expression associated with different developmental stages to each other to study patterns of long-term developmental gene regulation. We use tools from functional data analysis to study dynamic changes by relating temporal gene expression profiles of different developmental stages to each other. Results We demonstrate that functional regression methodology can pinpoint relationships that exist between temporary gene expression profiles for different life cycle phases and incorporates dimension reduction as needed for these high-dimensional data. By applying these tools, gene expression profiles for pupa and adult phases are found to be strongly related to the profiles of the same genes obtained during the embryo phase. Moreover, one can distinguish between gene groups that exhibit relationships with positive and others with negative associations between later life and embryonal expression profiles. Specifically, we find a positive relationship in expression for muscle development related genes, and a negative relationship for strictly maternal genes for Drosophila, using temporal gene expression profiles. Conclusion Our findings point to specific reactivation patterns of gene expression during the Drosophila life cycle which differ in characteristic ways between various gene groups. Functional regression emerges as a useful tool for relating gene expression patterns from different developmental stages, and avoids the problems with large numbers of parameters and multiple testing that affect alternative approaches.

'AER working group D on VVER safety analysis' minutes of the meeting in Rossendorf, Germany, 10-12 May 1999

International Nuclear Information System (INIS)

Siltanen, P.

1999-01-01

AER Working Group D on VVER reactor safety analysis held its eighth meeting in Research Centre Rossendorf during the period 10-12 May 1999. There were altogether 14 participants from eight member organizations. In addition to the general information exchange on recent activities, the topics of the meeting included: Final conclusions and lessons from the solution of the AER Dynamic Benchmark Problem No. 5 on a main steam header break accident; Validation of dynamics codes and the definition of a 6th dynamic benchmark; Safety analyses and reactivity issues: approaches and results; Advances in development of models and codes for reactor dynamics applications; Documentation of dynamic benchmark problems and solutions for the AER Benchmark Book; Future activities. (author)

Global dynamics of multi-group SEI animal disease models with indirect transmission

International Nuclear Information System (INIS)

Wang, Yi; Cao, Jinde

2014-01-01

A challenge to multi-group epidemic models in mathematical epidemiology is the exploration of global dynamics. Here we formulate multi-group SEI animal disease models with indirect transmission via contaminated water. Under biologically motivated assumptions, the basic reproduction number R 0 is derived and established as a sharp threshold that completely determines the global dynamics of the system. In particular, we prove that if R 0 <1, the disease-free equilibrium is globally asymptotically stable, and the disease dies out; whereas if R 0 >1, then the endemic equilibrium is globally asymptotically stable and thus unique, and the disease persists in all groups. Since the weight matrix for weighted digraphs may be reducible, the afore-mentioned approach is not directly applicable to our model. For the proofs we utilize the classical method of Lyapunov, graph-theoretic results developed recently and a new combinatorial identity. Since the multiple transmission pathways may correspond to the real world, the obtained results are of biological significance and possible generalizations of the model are also discussed

Health service resilience in Yobe state, Nigeria in the context of the Boko Haram insurgency: a systems dynamics analysis using group model building.

Science.gov (United States)

Ager, Alastair K; Lembani, Martina; Mohammed, Abdulaziz; Mohammed Ashir, Garba; Abdulwahab, Ahmad; de Pinho, Helen; Delobelle, Peter; Zarowsky, Christina

2015-01-01

Yobe State has faced severe disruption of its health service as a result of the Boko Haram insurgency. A systems dynamics analysis was conducted to identify key pathways of threat to provision and emerging pathways of response and adaptation. Structured interviews were conducted with 39 stakeholders from three local government areas selected to represent the diversity of conflict experience across the state: Damaturu, Fune and Nguru, and with four officers of the PRRINN-MNCH program providing technical assistance for primary care development in the state. A group model building session was convened with 11 senior stakeholders, which used participatory scripts to review thematic analysis of interviews and develop a preliminary systems model linking identified variables. Population migration and transport restrictions have substantially impacted access to health provision. The human resource for health capability of the state has been severely diminished through the outward migration of (especially non-indigenous) health workers and the suspension of programmes providing external technical assistance. The political will of the Yobe State government to strengthen health provision - through lifting a moratorium on recruitment and providing incentives for retention and support of staff - has supported a recovery of health systems functioning. Policies of free-drug provision and decentralized drug supply appear to have been protective of the operation of the health system. Community resources and cohesion have been significant assets in combatting the impacts of the insurgency on service utilization and quality. Staff commitment and motivation - particularly amongst staff indigenous to the state - has protected health care quality and enabled flexibility of human resource deployment. A systems analysis using participatory group model building provided a mechanism to identify key pathways of threat and adaptation with regard to health service functioning. Generalizable

Qualitative Analysis of Collaborative Learning Groups in Large Enrollment Introductory Astronomy

Science.gov (United States)

Skala, Chija; Slater, Timothy F.; Adams, Jeffrey P.

2000-08-01

Large-lecture introductory astronomy courses for undergraduate, non-science majors present numerous problems for faculty. As part of a systematic effort to improve the course learning environment, a series of small-group, collaborative learning activities were implemented in an otherwise conventional lecture astronomy survey course. These activities were used once each week during the regularly scheduled lecture period. After eight weeks, ten focus group interviews were conducted to qualitatively assess the impact and dynamics of these small group learning activities. Overall, the data strongly suggest that students enjoy participating in the in-class learning activities in learning teams of three to four students. These students firmly believe that they are learning more than they would from lectures alone. Inductive analysis of the transcripts revealed five major themes prevalent among the students' perspectives: (1) self-formed, cooperative group composition and formation should be more regulated by the instructor; (2) team members' assigned rolls should be less formally structured by the instructors; (3) cooperative groups helped in learning the course content; (4) time constraints on lectures and activities need to be more carefully aligned; and (5) gender issues can exist within the groups. These themes serve as a guide for instructors who are developing instructional interventions for large lecture courses.

Effects of group dynamics and diet on the ranging patterns of a western gorilla group (Gorilla gorilla gorilla) at Bai Hokou, Central African Republic.

Science.gov (United States)

Cipolletta, Chloé

2004-10-01

This study describes how group dynamics and diet have influenced the ranging patterns of a western gorilla group at Bai Hokou, Central African Republic. The results are compared with those from an earlier study [Cipolletta, International Journal of Primatology, 2003], when the same group was larger and undergoing the process of habituation to humans. Data were obtained from maps of the gorillas' travel routes, direct observations, and analysis of fecal samples. Through the years, the group has experienced a decrease in size, from eight to three individuals, with periods of membership fluctuation. The male's search for new mates resulted in a larger home range than was recorded when the group consisted of more individuals. Moreover, despite an average group size of three throughout this study, the monthly range and mean daily path length (DPL) were also larger when the group was acquiring/losing members in new areas, than when no new members joined or left the group. Fruit was consumed year-round, although more heavily so during wet months. The influence of fruit consumption on the ranging patterns was concealed initially by the effect of habituation [Cipolletta, International Journal of Primatology, 2003], and later (at least partially) by the male's search for new mates. In the last 14 months of the study, when the group numbered only three individuals and was ranging in a restricted area, the average DPL, but not the monthly range, increased when the gorillas were consuming more fruit.

Intra-Party Dynamics and the Political Transformation of Non-State Armed Groups

Directory of Open Access Journals (Sweden)

Véronique Dudouet

2012-05-01

Full Text Available Although non-state armed groups are primary stakeholders in contemporary political conflicts, there has been little research into their members’ perspectives on internal factors shaping radicalisation and de-radicalisation. State and international actors often assume that bringing rebel leaders to the negotiating table or “converting” them to peaceful politicians means weakening, splitting, or dismantling militant structures. This paper re-evaluates those assumptions in the light of rebel leaders’ own accounts of internal organisational dynamics before, during, and after political conflicts and peace settlements. Participatory action research with “insider experts” from armed movements in Northern Ireland, Kosovo, Nepal, Aceh, El Salvador, Colombia, and South Africa reveals insiders’ analysis of leadership and organisational dynamics during armed conflict and political talks and highlights the rational decision-making process whereby proactive leaders constantly (reassess and adjust their tactics (from unarmed to armed and vice versa as the strategic environment evolves. Horizontal and vertical communication between members is critical for enabling collective ownership of transformation processes from violent insurgency to peaceful transition and preventing internal splits and disaffection during peace negotiations. The claim that rebel organisations should be dismantled as quickly as possible during peace processes is found to be dubious, highlighting instead the importance of retaining cohesive coordination and communication structures during volatile post-war transitions.

New Frontiers in Analyzing Dynamic Group Interactions : Bridging Social and Computer Science

NARCIS (Netherlands)

Lehmann-Willenbrock, Nale; Hung, H.S.; Keyton, Joann

2017-01-01

This special issue on advancing interdisciplinary collaboration between computer scientists and social scientists documents the joint results of the international Lorentz workshop, “Interdisciplinary Insights into Group and Team Dynamics,” which took place in Leiden, The Netherlands, July 2016.

Solar Dynamic Power System Stability Analysis and Control

Science.gov (United States)

Momoh, James A.; Wang, Yanchun

1996-01-01

The objective of this research is to conduct dynamic analysis, control design, and control performance test of solar power system. Solar power system consists of generation system and distribution network system. A bench mark system is used in this research, which includes a generator with excitation system and governor, an ac/dc converter, six DDCU's and forty-eight loads. A detailed model is used for modeling generator. Excitation system is represented by a third order model. DDCU is represented by a seventh order system. The load is modeled by the combination of constant power and constant impedance. Eigen-analysis and eigen-sensitivity analysis are used for system dynamic analysis. The effects of excitation system, governor, ac/dc converter control, and the type of load on system stability are discussed. In order to improve system transient stability, nonlinear ac/dc converter control is introduced. The direct linearization method is used for control design. The dynamic analysis results show that these controls affect system stability in different ways. The parameter coordination of controllers are recommended based on the dynamic analysis. It is concluded from the present studies that system stability is improved by the coordination of control parameters and the nonlinear ac/dc converter control stabilize system oscillation caused by the load change and system fault efficiently.

A study of collective coordinates and dynamical groups in nuclear theory

International Nuclear Information System (INIS)

Papadopolos, Z.

1983-01-01

Lie-algebraic techniques for the group action on manifolds given as a direct product of coset spaces and group manifolds are developed. The microscopic realisation of the Mass Quadrupole Collective Model (MQC) in the S0(3)xSO(n) and GLsub(+)(3, R)xSO(n) schemes is studied. The problem of the separation of the kinetic energy and the velocity field into a collective and an intrinsic part is analyzed. Different coordinate schemes in phase space for the U(n)-invariant collective motion and the U(3) dynamical group are introduced. In the GL(3,C)xU(n) scheme, the invariant volume element in the new coordinates and a completely orthonormal basis is constructed. (orig.) [de

Analysis and control of complex dynamical systems robust bifurcation, dynamic attractors, and network complexity

CERN Document Server

Imura, Jun-ichi; Ueta, Tetsushi

2015-01-01

This book is the first to report on theoretical breakthroughs on control of complex dynamical systems developed by collaborative researchers in the two fields of dynamical systems theory and control theory. As well, its basic point of view is of three kinds of complexity: bifurcation phenomena subject to model uncertainty, complex behavior including periodic/quasi-periodic orbits as well as chaotic orbits, and network complexity emerging from dynamical interactions between subsystems. Analysis and Control of Complex Dynamical Systems offers a valuable resource for mathematicians, physicists, and biophysicists, as well as for researchers in nonlinear science and control engineering, allowing them to develop a better fundamental understanding of the analysis and control synthesis of such complex systems.

Discrete dynamic event tree modeling and analysis of nuclear power plant crews for safety assessment

International Nuclear Information System (INIS)

Mercurio, D.

2011-01-01

Current Probabilistic Risk Assessment (PRA) and Human Reliability Analysis (HRA) methodologies model the evolution of accident sequences in Nuclear Power Plants (NPPs) mainly based on Logic Trees. The evolution of these sequences is a result of the interactions between the crew and plant; in current PRA methodologies, simplified models of these complex interactions are used. In this study, the Accident Dynamic Simulator (ADS), a modeling framework based on the Discrete Dynamic Event Tree (DDET), has been used for the simulation of crew-plant interactions during potential accident scenarios in NPPs. In addition, an operator/crew model has been developed to treat the response of the crew to the plant. The 'crew model' is made up of three operators whose behavior is guided by a set of rules-of-behavior (which represents the knowledge and training of the operators) coupled with written and mental procedures. In addition, an approach for addressing the crew timing variability in DDETs has been developed and implemented based on a set of HRA data from a simulator study. Finally, grouping techniques were developed and applied to the analysis of the scenarios generated by the crew-plant simulation. These techniques support the post-simulation analysis by grouping similar accident sequences, identifying the key contributing events, and quantifying the conditional probability of the groups. These techniques are used to characterize the context of the crew actions in order to obtain insights for HRA. The model has been applied for the analysis of a Small Loss Of Coolant Accident (SLOCA) event for a Pressurized Water Reactor (PWR). The simulation results support an improved characterization of the performance conditions or context of operator actions, which can be used in an HRA, in the analysis of the reliability of the actions. By providing information on the evolution of system indications, dynamic of cues, crew timing in performing procedure steps, situation

An algebraic approach to the inverse eigenvalue problem for a quantum system with a dynamical group

International Nuclear Information System (INIS)

Wang, S.J.

1993-04-01

An algebraic approach to the inverse eigenvalue problem for a quantum system with a dynamical group is formulated for the first time. One dimensional problem is treated explicitly in detail for both the finite dimensional and infinite dimensional Hilbert spaces. For the finite dimensional Hilbert space, the su(2) algebraic representation is used; while for the infinite dimensional Hilbert space, the Heisenberg-Weyl algebraic representation is employed. Fourier expansion technique is generalized to the generator space, which is suitable for analysis of irregular spectra. The polynormial operator basis is also used for complement, which is appropriate for analysis of some simple Hamiltonians. The proposed new approach is applied to solve the classical inverse Sturn-Liouville problem and to study the problems of quantum regular and irregular spectra. (orig.)

Some Remarks on Group Bundles and C*-dynamical systems

OpenAIRE

Vasselli, Ezio

2003-01-01

We introduce the notion of fibred action of a group bundle on a C(X)-algebra. By using such a notion, a characterization in terms of induced C*-bundles is given for C*-dynamical systems such that the relative commutant of the fixed-point algebra is minimal (i.e., it is generated by the centre of the given C*-algebra and the centre of the fixed-point algebra). A class of examples in the setting of the Cuntz algebra is given, and connections with superselection structures with nontrivial centre...

Some Remarks on Group Bundles and C* Dynamical Systems

Science.gov (United States)

Vasselli, Ezio

2007-08-01

We introduce the notion of fibred action of a group bundle on a C(X)-algebra. By using such a notion, a characterization in terms of induced C*-bundles is given for C*-dynamical systems such that the relative commutant of the fixed-point C*-algebra is minimal (i.e., it is generated by the centre of the given C*-algebra and the centre of the fixed-point C*-algebra). A class of examples in the setting of the Cuntz algebra is given, and connections with superselection structures with nontrivial centre are discussed.

Dynamic Analysis of Tele-manipulator

Energy Technology Data Exchange (ETDEWEB)

Kang, Min Sig; Lee, Seung Hyun; Kim, Doo Ho; Choi, Sun Il [Kyungwon Univ., Sungnam (Korea, Republic of)

2008-03-15

The manipulator can move linearly along X and Y-axes and has 6-degree rotational freedom. All deriving electric motors are mounted on the base platform to reduce inertia of links and tendons are used to transmit torque from the motors to the corresponding joints. In this report, a dynamic analysis of the manipulator has been carried out. Based on the dimensions of the designed links and allowable maximum rotational constraints on all joints, the maximum torque has been analyzed and working volume has been derived graphically through a numerical analysis. The Danavit-Hartenverg coordinate has been used through out this report. An inverse kinematic model which includes 3-linear and 3-rotational motions of the end effector and its numerical simulation program have been developed. The simulation results showed its validity and usefulness. The program are written in Symbolic Math provided by MatLab. A dynamic model which consists of rigid link dynamic models , driving motors and tendons which are used to tranmit the torques between motors and the corresponding joints. A simulation model written in Simmechanics has been derived and its validity and its usefulness were verified along with some simulation results.

Dynamic Analysis of Tele-manipulator

International Nuclear Information System (INIS)

Kang, Min Sig; Lee, Seung Hyun; Kim, Doo Ho; Choi, Sun Il

2008-03-01

The manipulator can move linearly along X and Y-axes and has 6-degree rotational freedom. All deriving electric motors are mounted on the base platform to reduce inertia of links and tendons are used to transmit torque from the motors to the corresponding joints. In this report, a dynamic analysis of the manipulator has been carried out. Based on the dimensions of the designed links and allowable maximum rotational constraints on all joints, the maximum torque has been analyzed and working volume has been derived graphically through a numerical analysis. The Danavit-Hartenverg coordinate has been used through out this report. An inverse kinematic model which includes 3-linear and 3-rotational motions of the end effector and its numerical simulation program have been developed. The simulation results showed its validity and usefulness. The program are written in Symbolic Math provided by MatLab. A dynamic model which consists of rigid link dynamic models , driving motors and tendons which are used to tranmit the torques between motors and the corresponding joints. A simulation model written in Simmechanics has been derived and its validity and its usefulness were verified along with some simulation results

Building consensus in strategic decision-making : system dynamics as a group support system

OpenAIRE

Vennix, J.A.M.

1995-01-01

System dynamics was originally founded as a method for modeling and simulating the behavior of industrial systems. In recent years it is increasingly employed as a Group Support System for strategic decision-making groups. The model is constructed in direct interaction with a management team, and the procedure is generally referred to as group model-building. The model can be conceptual (qualitative) or a full-blown (quantitative) computer simulation model. In this article, a case is describe...

Vehicle systems: coupled and interactive dynamics analysis

Science.gov (United States)

Vantsevich, Vladimir V.

2014-11-01

This article formulates a new direction in vehicle dynamics, described as coupled and interactive vehicle system dynamics. Formalised procedures and analysis of case studies are presented. An analytical consideration, which explains the physics of coupled system dynamics and its consequences for dynamics of a vehicle, is given for several sets of systems including: (i) driveline and suspension of a 6×6 truck, (ii) a brake mechanism and a limited slip differential of a drive axle and (iii) a 4×4 vehicle steering system and driveline system. The article introduces a formal procedure to turn coupled system dynamics into interactive dynamics of systems. A new research direction in interactive dynamics of an active steering and a hybrid-electric power transmitting unit is presented and analysed to control power distribution between the drive axles of a 4×4 vehicle. A control strategy integrates energy efficiency and lateral dynamics by decoupling dynamics of the two systems thus forming their interactive dynamics.

Role of Dispersive Fluorous Interaction in the Solvation Dynamics of the Perfluoro Group Containing Molecules.

Science.gov (United States)

Mondal, Saptarsi; Chaterjee, Soumit; Halder, Ritaban; Jana, Biman; Singh, Prashant Chandra

2017-08-17

Perfluoro group containing molecules possess an important self-aggregation property through the fluorous (F···F) interaction which makes them useful for diverse applications such as medicinal chemistry, separation techniques, polymer technology, and biology. In this article, we have investigated the solvation dynamics of coumarin-153 (C153) and coumarin-6H (C6H) in ethanol (ETH), 2-fluoroethanol (MFE), and 2,2,2-trifluoroethanol (TFE) using the femtosecond upconversion technique and molecular dynamics (MD) simulation to understand the role of fluorous interaction between the solute and solvent molecules in the solvation dynamics of perfluoro group containing molecules. The femtosecond upconversion data show that the time scales of solvation dynamics of C6H in ETH, MFE, and TFE are approximately the same whereas the solvation dynamics of C153 in TFE is slow as compared to that of ETH and MFE. It has also been observed that the time scale of solvation dynamics of C6H in ETH and MFE is higher than that of C153 in the same solvents. MD simulation results show a qualitative agreement with the experimental data in terms of the time scale of the slow components of the solvation for all the systems. The experimental and simulation studies combined lead to the conclusion that the solvation dynamics of C6H in all solvents as well as C153 in ETH and MFE is mostly governed by the charge distribution of ester moieties (C═O and O) of dye molecules whereas the solvation of C153 in TFE is predominantly due to the dispersive fluorous interaction (F···F) between the perfluoro groups of the C153 and solvent molecules.

Integrating atomistic molecular dynamics simulations, experiments, and network analysis to study protein dynamics

DEFF Research Database (Denmark)

Papaleo, Elena

2015-01-01

that we observe and the functional properties of these important cellular machines. To make progresses in this direction, we need to improve the physical models used to describe proteins and solvent in molecular dynamics, as well as to strengthen the integration of experiments and simulations to overcome...... with the possibility to validate simulation methods and physical models against a broad range of experimental observables. On the other side, it also allows a complementary and comprehensive view on protein structure and dynamics. What is needed now is a better understanding of the link between the dynamic properties...... simulations with attention to the effects that can be propagated over long distances and are often associated to important biological functions. In this context, approaches inspired by network analysis can make an important contribution to the analysis of molecular dynamics simulations....

Direct assignment of molecular vibrations via normal mode analysis of the neutron dynamic pair distribution function technique

International Nuclear Information System (INIS)

Fry-Petit, A. M.; Sheckelton, J. P.; McQueen, T. M.; Rebola, A. F.; Fennie, C. J.; Mourigal, M.; Valentine, M.; Drichko, N.

2015-01-01

For over a century, vibrational spectroscopy has enhanced the study of materials. Yet, assignment of particular molecular motions to vibrational excitations has relied on indirect methods. Here, we demonstrate that applying group theoretical methods to the dynamic pair distribution function analysis of neutron scattering data provides direct access to the individual atomic displacements responsible for these excitations. Applied to the molecule-based frustrated magnet with a potential magnetic valence-bond state, LiZn 2 Mo 3 O 8 , this approach allows direct assignment of the constrained rotational mode of Mo 3 O 13 clusters and internal modes of MoO 6 polyhedra. We anticipate that coupling this well known data analysis technique with dynamic pair distribution function analysis will have broad application in connecting structural dynamics to physical properties in a wide range of molecular and solid state systems

Dynamic analysis of hybrid energy systems under flexible operation and variable renewable generation – Part II: Dynamic cost analysis

International Nuclear Information System (INIS)

Garcia, Humberto E.; Mohanty, Amit; Lin, Wen-Chiao; Cherry, Robert S.

2013-01-01

Dynamic analysis of HES (hybrid energy systems) under flexible operation and variable renewable generation is considered in this two-part communication to better understand various challenges and opportunities associated with the high system variability arising from the integration of renewable energy into the power grid. Advanced HES solutions are investigated in which multiple forms of energy commodities, such as electricity and chemical products, may be exchanged. In particular, a comparative dynamic cost analysis is conducted in this part two of the communication to determine best HES options. The cost function includes a set of metrics for computing fixed costs, such as fixed operations and maintenance and overnight capital costs, and also variable operational costs, such as cost of operational variability, variable operations and maintenance cost, and cost of environmental impact, together with revenues. Assuming natural gas, coal, and nuclear as primary heat sources, preliminary results identify the level of renewable penetration at which a given advanced HES option (e.g., a nuclear hybrid) becomes increasingly more economical than a traditional electricity-only generation solution. Conditions are also revealed under which carbon resources may be better utilized as carbon sources for chemical production rather than as combustion material for electricity generation. - Highlights: ► Dynamic analysis of HES to investigate challenges related to renewable penetration. ► Evaluation of dynamic synergies among HES constituents on system performance. ► Comparison of traditional versus advanced HES candidates. ► Dynamic cost analysis of HES candidates to investigate their economic viability. ► Identification of conditions under which an energy commodity may be best utilized

Group Psychotherapy in Denmark.

Science.gov (United States)

Jørgensen, Lars Bo; Thygesen, Bente; Aagaard, Søren

2015-10-01

This is a short article on the history and training standards in the Institute of Group Analysis in Copenhagen (IGA-CPH). We describe theoretical orientations and influences in the long-term training program and new initiatives, like courses in mentalization-based group treatment and a dynamic short-term group therapy course, as well as research in group psychotherapy in Denmark. Some group analytic initiatives in relation to social issues and social welfare are presented, as well as initiatives concerning the school system and unemployment.

Advances in analysis and control of timedelayed dynamical systems

CERN Document Server

Sun, Jianqiao

2013-01-01

Analysis and control of timedelayed systems have been applied in a wide range of applications, ranging from mechanical, control, economic, to biological systems. Over the years, there has been a steady stream of interest in timedelayed dynamic systems, this book takes a snap shot of recent research from the world leading experts in analysis and control of dynamic systems with time delay to provide a bird's eye view of its development. The topics covered in this book include solution methods, stability analysis and control of periodic dynamic systems with time delay, bifurcations, stochastic dy

Dynamic remodeling of in-group bias during the 2008 presidential election.

Science.gov (United States)

Rand, David G; Pfeiffer, Thomas; Dreber, Anna; Sheketoff, Rachel W; Wernerfelt, Nils C; Benkler, Yochai

2009-04-14

People often favor members of their own group, while discriminating against members of other groups. Such in-group favoritism has been shown to play an important role in human cooperation. However, in the face of changing conflicts and shifting alliances, it is essential for group identities to be flexible. Using the dictator game from behavioral economics, we demonstrate the remodeling of group identities among supporters of Democratic presidential candidates Barack Obama and Hillary Clinton. After Clinton's concession in June 2008, Democrats were more generous toward supporters of their own preferred candidate than to supporters of the other Democratic candidate. The bias observed in June persisted into August, and disappeared only in early September after the Democratic National Convention. We also observe a strong gender effect, with bias both appearing and subsiding among men only. This experimental study illustrates a dynamic change in bias, tracking the realignment of real world conflict lines and public efforts to reconstitute group identity. The change in salient group identity we describe here likely contributed to the victory of Barack Obama in the 2008 presidential election.

Fixed geometric formation structure in formation control problem for group of robots with dynamically changing number of robots in the group

Directory of Open Access Journals (Sweden)

N. S. Morozova

2015-01-01

Full Text Available The article considers a problem of the decentralization-based approach to formation control of a group of agents, which simulate mobile autonomous robots. The agents use only local information limited by the covering range of their sensors. The agents have to build and maintain the formation, which fits to the defined target geometric formation structure with desired accuracy during the movement to the target point. At any point in time the number of agents in the group can change unexpectedly (for example, as a result of the agent failure or if a new agent joins the group.The aim of the article is to provide the base control rule, which solves the formation control problem, and to develop its modifications, which provide the correct behavior in case the agent number in the group is not equal to the size of the target geometric formation structure. The proposed base control rule, developed by the author, uses the method of involving virtual leaders. The coordinates of the virtual leaders and also the priority to follow the specific leader are calculated by each agent itself according to specific rules.The following results are presented in the article: the base control rule for solving the formation control problem, its modifications for the cases when the number of agents is greater/less than the size of the target geometric formation structure and also the computer modeling results proving the efficiency of the modified control rules. The specific feature of the control rule, developed by the author, is that each agent itself calculates the virtual leaders and each agent performs dynamic choice of the place within the formation (there is no predefined one-to-one relation between agents and places within the geometric formation structure. The results, provided in this article, can be used in robotics for developing control algorithms for the tasks, which require preserving specific relational positions among the agents while moving. One of the

A Mathematical Framework for the Complex System Approach to Group Dynamics: The Case of Recovery House Social Integration.

Science.gov (United States)

Light, John M; Jason, Leonard A; Stevens, Edward B; Callahan, Sarah; Stone, Ariel

2016-03-01

The complex system conception of group social dynamics often involves not only changing individual characteristics, but also changing within-group relationships. Recent advances in stochastic dynamic network modeling allow these interdependencies to be modeled from data. This methodology is discussed within a context of other mathematical and statistical approaches that have been or could be applied to study the temporal evolution of relationships and behaviors within small- to medium-sized groups. An example model is presented, based on a pilot study of five Oxford House recovery homes, sober living environments for individuals following release from acute substance abuse treatment. This model demonstrates how dynamic network modeling can be applied to such systems, examines and discusses several options for pooling, and shows how results are interpreted in line with complex system concepts. Results suggest that this approach (a) is a credible modeling framework for studying group dynamics even with limited data, (b) improves upon the most common alternatives, and (c) is especially well-suited to complex system conceptions. Continuing improvements in stochastic models and associated software may finally lead to mainstream use of these techniques for the study of group dynamics, a shift already occurring in related fields of behavioral science.

Molecular dynamics simulations of single siloxane dendrimers: Molecular structure and intramolecular mobility of terminal groups

Science.gov (United States)

Kurbatov, A. O.; Balabaev, N. K.; Mazo, M. A.; Kramarenko, E. Yu.

2018-01-01

Molecular dynamics simulations of two types of isolated siloxane dendrimers of various generations (from the 2nd to the 8th) have been performed for temperatures ranging from 150 K to 600 K. The first type of dendrimer molecules has short spacers consisting of a single oxygen atom. In the dendrimers of the second type, spacers are longer and comprised of two oxygen atoms separated by a single silicon atom. A comparative analysis of molecular macroscopic parameters such as the gyration radius and the shape factor as well as atom distributions within dendrimer interior has been performed for varying generation number, temperature, and spacer length. It has been found that the short-spacer dendrimers of the 7th and 8th generations have a stressed central part with elongated bonds and deformed valence angles. Investigation of the time evolution of radial displacements of the terminal Si atoms has shown that a fraction of the Si groups have a reduced mobility. Therefore, rather long time trajectories (of the order of tens of nanoseconds) are required to study dendrimer intramolecular dynamics.

A CAREM type fuel element dynamic analysis

International Nuclear Information System (INIS)

Magoia, J.E.

1990-01-01

A first analysis on the dynamic behaviour of a fuel element designed for the CAREM nuclear reactor (Central Argentina de Elementos Modulares) was performed. The model used to represent this dynamic behaviour was satisfactorily evaluated. Using primary estimations for some of its numerical parameters, a first approximation to its natural vibrational modes was obtained. Results obtained from fuel elements frequently used in nuclear power plants of the PWR (Pressurized Water Reactors) type, are compared with values resulting from similar analysis. (Author) [es

Model Independent Analysis of Beam Centroid Dynamics in Accelerators

International Nuclear Information System (INIS)

Wang, Chun-xi

2003-01-01

Fundamental issues in Beam-Position-Monitor (BPM)-based beam dynamics observations are studied in this dissertation. The major topic is the Model-Independent Analysis (MIA) of beam centroid dynamics. Conventional beam dynamics analysis requires a certain machine model, which itself of ten needs to be refined by beam measurements. Instead of using any particular machine model, MIA relies on a statistical analysis of the vast amount of BPM data that often can be collected non-invasively during normal machine operation. There are two major parts in MIA. One is noise reduction and degrees-of-freedom analysis using a singular value decomposition of a BPM-data matrix, which constitutes a principal component analysis of BPM data. The other is a physical base decomposition of the BPM-data matrix based on the time structure of pulse-by-pulse beam and/or machine parameters. The combination of these two methods allows one to break the resolution limit set by individual BPMs and observe beam dynamics at more accurate levels. A physical base decomposition is particularly useful for understanding various beam dynamics issues. MIA improves observation and analysis of beam dynamics and thus leads to better understanding and control of beams in both linacs and rings. The statistical nature of MIA makes it potentially useful in other fields. Another important topic discussed in this dissertation is the measurement of a nonlinear Poincare section (one-turn) map in circular accelerators. The beam dynamics in a ring is intrinsically nonlinear. In fact, nonlinearities are a major factor that limits stability and influences the dynamics of halos. The Poincare section map plays a basic role in characterizing and analyzing such a periodic nonlinear system. Although many kinds of nonlinear beam dynamics experiments have been conducted, no direct measurement of a nonlinear map has been reported for a ring in normal operation mode. This dissertation analyzes various issues concerning map

Model Independent Analysis of Beam Centroid Dynamics in Accelerators

Energy Technology Data Exchange (ETDEWEB)

Wang, Chun-xi

2003-04-21

Fundamental issues in Beam-Position-Monitor (BPM)-based beam dynamics observations are studied in this dissertation. The major topic is the Model-Independent Analysis (MIA) of beam centroid dynamics. Conventional beam dynamics analysis requires a certain machine model, which itself of ten needs to be refined by beam measurements. Instead of using any particular machine model, MIA relies on a statistical analysis of the vast amount of BPM data that often can be collected non-invasively during normal machine operation. There are two major parts in MIA. One is noise reduction and degrees-of-freedom analysis using a singular value decomposition of a BPM-data matrix, which constitutes a principal component analysis of BPM data. The other is a physical base decomposition of the BPM-data matrix based on the time structure of pulse-by-pulse beam and/or machine parameters. The combination of these two methods allows one to break the resolution limit set by individual BPMs and observe beam dynamics at more accurate levels. A physical base decomposition is particularly useful for understanding various beam dynamics issues. MIA improves observation and analysis of beam dynamics and thus leads to better understanding and control of beams in both linacs and rings. The statistical nature of MIA makes it potentially useful in other fields. Another important topic discussed in this dissertation is the measurement of a nonlinear Poincare section (one-turn) map in circular accelerators. The beam dynamics in a ring is intrinsically nonlinear. In fact, nonlinearities are a major factor that limits stability and influences the dynamics of halos. The Poincare section map plays a basic role in characterizing and analyzing such a periodic nonlinear system. Although many kinds of nonlinear beam dynamics experiments have been conducted, no direct measurement of a nonlinear map has been reported for a ring in normal operation mode. This dissertation analyzes various issues concerning map

Essentials of applied dynamic analysis

CERN Document Server

Jia, Junbo

2014-01-01

This book presents up-to-date knowledge of dynamic analysis in engineering world. To facilitate the understanding of the topics by readers with various backgrounds, general principles are linked to their applications from different angles. Special interesting topics such as statistics of motions and loading, damping modeling and measurement, nonlinear dynamics, fatigue assessment, vibration and buckling under axial loading, structural health monitoring, human body vibrations, and vehicle-structure interactions etc., are also presented. The target readers include industry professionals in civil, marine and mechanical engineering, as well as researchers and students in this area.

Evaluation of Offshore Wind Turbine Tower Dynamics with Numerical Analysis

Directory of Open Access Journals (Sweden)

Begum Yurdanur Dagli

2018-01-01

Full Text Available A dynamic behaviour of a cylindirical wind tower with variable cross section is investigated under environmental and earthquake forces. The ground acceleration term is represented by a simple cosine function to investigate both normal and parallel components of the earthquake motions located near ground surface. The function of earthquake force is simplified to apply Rayleigh’s energy method. Wind forces acting on above the water level and wave forces acting on below this level are utilized in computations considering earthquake effect for entire structure. The wind force is divided into two groups: the force acting on the tower and the forces acting on the rotor nacelle assembly (RNA. The drag and the inertial wave forces are calculated with water particle velocities and accelerations due to linear wave theory. The resulting hydrodynamic wave force on the tower in an unsteady viscous flow is determined using the Morison equation. The displacement function of the physical system in which dynamic analysis is performed by Rayleigh’s energy method is obtained by the single degree of freedom (SDOF model. The equation of motion is solved by the fourth-order Runge–Kutta method. The two-way FSI (fluid-structure interaction technique was used to determine the accuracy of the numerical analysis. The results of computational fluid dynamics and structural mechanics are coupled in FSI analysis by using ANSYS software. Time-varying lateral displacements and the first natural frequency values which are obtained from Rayleigh’s energy method and FSI technique are compared. The results are presented by graphs. It is observed from these graphs that the Rayleigh model can be an alternative way at the prelimanary stage of the structural analysis with acceptable accuracy.

Analysis of pile foundations under dynamic loads

International Nuclear Information System (INIS)

Waas, G.; Hartmann, H.G.

1981-01-01

A method is presented for the analysis of pile foundations which are subjected to horizontal dynamic loads from earthquakes, airplane impact, gas explosion or other sources. The motion of the pile cap and the pile forces are computed. - The loads may be applied to the pile cap or directly to the piles (e.g. by earthquake wave motion). The soil may be stratified and is considered to be an elastic or visco-elastic medium. The piles are assumed vertical. The method makes use of an approximate fundamental solution for displacements caused by a dynamic point load in a layered visco-elastic medium. The approximation involves a discretization of the medium in the vertical direction. In horizontal directions the medium is treated by continuum theory. The soil medium supports each pile at about 10 to 20 nodes. A dynamic flexiblity matrix for the soil is derived which relates the elastic, damping and inertial forces of the soil to the displacements at each node. It includes effects of radiation damping. All piles are coupled through the soil flexibility matrix. The piles are modelled by beam elements. Transient response is computed using fast discrete Fourier transforms. The arrangement of the piles is arbitrary. However, simple and double symmetry can be accounted for by the computer program. When the pile arrangement is axisymmetric, the degrees of freedom can be reduced to only those of two piles per ring. The influence of the number of piles and the influence of the pile spacing on group stiffness and on pile forces is presented for two soil profiles. Dynamic effects on pile forces of a foundation for a reactor building are studied. They are significant when soils are soft. (orig.)

Spectral analysis of bedform dynamics

DEFF Research Database (Denmark)

Winter, Christian; Ernstsen, Verner Brandbyge; Noormets, Riko

Successive multibeam echo sounder surveys in tidal channels off Esbjerg (Denmark) on the North Sea coast reveal the dynamics of subaquatic compound dunes. Mainly driven by tidal currents, dune structures show complex migration patterns in all temporal and spatial scales. Common methods for the an....... The proposed method overcomes the above mentioned problems of common descriptive analysis as it is an objective and straightforward mathematical process. The spectral decomposition of superimposed dunes allows a detailed description and analysis of dune patterns and migration.......Successive multibeam echo sounder surveys in tidal channels off Esbjerg (Denmark) on the North Sea coast reveal the dynamics of subaquatic compound dunes. Mainly driven by tidal currents, dune structures show complex migration patterns in all temporal and spatial scales. Common methods...... allows the application of a procedure, which has been a standard for the analysis of water waves for long times: The bathymetric signal of a cross-section of subaquatic compound dunes is approximated by the sum of a set of harmonic functions, derived by Fourier transformation. If the wavelength...

The Group's Absence Norm and Commitment to the Group as Predictors of Group Member Absence in the Next Session: An Actor-Partner Analysis

Science.gov (United States)

Kivlighan, Dennis M., Jr.; Kivlighan, D. Martin, III; Cole, Odessa Dorian

2012-01-01

The group's absence norm, a construct from the applied psychology literature, was used to examine session absences in personal growth groups. Rather than examining the absence norm statically, we modeled it dynamically as a time-varying covariate (Tasca et al., 2010). We also examined moderation by modeling the interaction of the absence norm and…

Dynamics and vibrations progress in nonlinear analysis

CERN Document Server

Kachapi, Seyed Habibollah Hashemi

2014-01-01

Dynamical and vibratory systems are basically an application of mathematics and applied sciences to the solution of real world problems. Before being able to solve real world problems, it is necessary to carefully study dynamical and vibratory systems and solve all available problems in case of linear and nonlinear equations using analytical and numerical methods. It is of great importance to study nonlinearity in dynamics and vibration; because almost all applied processes act nonlinearly, and on the other hand, nonlinear analysis of complex systems is one of the most important and complicated tasks, especially in engineering and applied sciences problems. There are probably a handful of books on nonlinear dynamics and vibrations analysis. Some of these books are written at a fundamental level that may not meet ambitious engineering program requirements. Others are specialized in certain fields of oscillatory systems, including modeling and simulations. In this book, we attempt to strike a balance between th...

Dynamic analysis of CHASNUPP steam generator structure during shipping

International Nuclear Information System (INIS)

Han Liangbi; Xu Jinkang; Zhou Meiwu; He Yinbiao

1998-07-01

The dynamic analysis of CHASNUPP steam generator during shipping is described, including the simplified mathematical model, acceleration power spectrum of ocean wave induced random vibration, the dynamic analysis of steam generator structure under random loading, the applied computer code and calculated results

Modal and Dynamic Analysis of a Vehicle with Kinetic Dynamic Suspension System

Directory of Open Access Journals (Sweden)

Bangji Zhang

2016-01-01

Full Text Available A novel kinetic dynamic suspension (KDS system is presented for the cooperative control of the roll and warp motion modes of off-road vehicles. The proposed KDS system consists of two hydraulic cylinders acting on the antiroll bars. Hence, the antiroll bars are not completely replaced by the hydraulic system, but both systems are installed. In this paper, the vibration analysis in terms of natural frequencies of different motion modes in frequency domain for an off-road vehicle equipped with different configurable suspension systems is studied by using the modal analysis method. The dynamic responses of the vehicle with different configurable suspension systems are investigated under different road excitations and maneuvers. The results of the modal and dynamic analysis prove that the KDS system can reduce the roll and articulation motions of the off-road vehicle without adding extra bounce stiffness and deteriorating the ride comfort. Furthermore, the roll stiffness is increased and the warp stiffness is decreased by the KDS system, which could significantly enhance handing performance and off-road capability.

Density matrix renormalization group with efficient dynamical electron correlation through range separation

DEFF Research Database (Denmark)

Hedegård, Erik D.; Knecht, Stefan; Kielberg, Jesper Skau

2015-01-01

We present a new hybrid multiconfigurational method based on the concept of range-separation that combines the density matrix renormalization group approach with density functional theory. This new method is designed for the simultaneous description of dynamical and static electroncorrelation...... effects in multiconfigurational electronic structure problems....

Dominance dynamics of competition between intrinsic and extrinsic grouping cues.

Science.gov (United States)

Luna, Dolores; Villalba-García, Cristina; Montoro, Pedro R; Hinojosa, José A

2016-10-01

In the present study we examined the dominance dynamics of perceptual grouping cues. We used a paradigm in which participants selectively attended to perceptual groups based on several grouping cues in different blocks of trials. In each block, single and competing grouping cues were presented under different exposure durations (50, 150 or 350ms). Using this procedure, intrinsic vs. intrinsic cues (i.e. proximity and shape similarity) were compared in Experiment 1; extrinsic vs. extrinsic cues (i.e. common region and connectedness) in Experiment 2; and intrinsic vs. extrinsic cues (i.e. common region and shape similarity) in Experiment 3. The results showed that in Experiment 1, no dominance of any grouping cue was found: shape similarity and proximity grouping cues showed similar reaction times (RTs) and interference effects. In contrast, in Experiments 2 and 3, common region dominated processing: (i) RTs to common region were shorter than those to connectedness (Exp. 2) or shape similarity (Exp. 3); and (ii) when the grouping cues competed, common region interfered with connectedness (Exp. 2) and shape similarity (Exp. 3) more than vice versa. The results showed that the exposure duration of stimuli only affected the connectedness grouping cue. An important result of our experiments indicates that when two grouping cues compete, both the non-attended intrinsic cue in Experiment 1, and the non-dominant extrinsic cue in Experiments 2 and 3, are still perceived and they are not completely lost. Copyright © 2016 Elsevier B.V. All rights reserved.

Dynamic performances analysis of a real vehicle driving

Science.gov (United States)

Abdullah, M. A.; Jamil, J. F.; Salim, M. A.

2015-12-01

Vehicle dynamic is the effects of movement of a vehicle generated from the acceleration, braking, ride and handling activities. The dynamic behaviours are determined by the forces from tire, gravity and aerodynamic which acting on the vehicle. This paper emphasizes the analysis of vehicle dynamic performance of a real vehicle. Real driving experiment on the vehicle is conducted to determine the effect of vehicle based on roll, pitch, and yaw, longitudinal, lateral and vertical acceleration. The experiment is done using the accelerometer to record the reading of the vehicle dynamic performance when the vehicle is driven on the road. The experiment starts with weighing a car model to get the center of gravity (COG) to place the accelerometer sensor for data acquisition (DAQ). The COG of the vehicle is determined by using the weight of the vehicle. A rural route is set to launch the experiment and the road conditions are determined for the test. The dynamic performance of the vehicle are depends on the road conditions and driving maneuver. The stability of a vehicle can be controlled by the dynamic performance analysis.

Global dynamics of a novel multi-group model for computer worms

International Nuclear Information System (INIS)

Gong Yong-Wang; Song Yu-Rong; Jiang Guo-Ping

2013-01-01

In this paper, we study worm dynamics in computer networks composed of many autonomous systems. A novel multi-group SIQR (susceptible-infected-quarantined-removed) model is proposed for computer worms by explicitly considering anti-virus measures and the network infrastructure. Then, the basic reproduction number of worm R 0 is derived and the global dynamics of the model are established. It is shown that if R 0 is less than or equal to 1, the disease-free equilibrium is globally asymptotically stable and the worm dies out eventually, whereas, if R 0 is greater than 1, one unique endemic equilibrium exists and it is globally asymptotically stable, thus the worm persists in the network. Finally, numerical simulations are given to illustrate the theoretical results. (general)

Dynamic thermal analysis of machines in running state

CERN Document Server

Wang, Lihui

2014-01-01

With the increasing complexity and dynamism in today’s machine design and development, more precise, robust and practical approaches and systems are needed to support machine design. Existing design methods treat the targeted machine as stationery. Analysis and simulation are mostly performed at the component level. Although there are some computer-aided engineering tools capable of motion analysis and vibration simulation etc., the machine itself is in the dry-run state. For effective machine design, understanding its thermal behaviours is crucial in achieving the desired performance in real situation. Dynamic Thermal Analysis of Machines in Running State presents a set of innovative solutions to dynamic thermal analysis of machines when they are put under actual working conditions. The objective is to better understand the thermal behaviours of a machine in real situation while at the design stage. The book has two major sections, with the first section presenting a broad-based review of the key areas of ...

Static Analysis for Dynamic XML

DEFF Research Database (Denmark)

Christensen, Aske Simon; Møller, Anders; Schwartzbach, Michael Ignatieff

2002-01-01

We describe the summary graph lattice for dataflow analysis of programs that dynamically construct XML documents. Summary graphs have successfully been used to provide static guarantees in the JWIG language for programming interactive Web services. In particular, the JWIG compiler is able to check...

The primary case is not enough: Variation among individuals, groups and social networks modify bacterial transmission dynamics.

Science.gov (United States)

Keiser, Carl N; Pinter-Wollman, Noa; Ziemba, Michael J; Kothamasu, Krishna S; Pruitt, Jonathan N

2018-03-01

The traits of the primary case of an infectious disease outbreak, and the circumstances for their aetiology, potentially influence the trajectory of transmission dynamics. However, these dynamics likely also depend on the traits of the individuals with whom the primary case interacts. We used the social spider Stegodyphus dumicola to test how the traits of the primary case, group phenotypic composition and group size interact to facilitate the transmission of a GFP-labelled cuticular bacterium. We also compared bacterial transmission across experimentally generated "daisy-chain" vs. "star" networks of social interactions. Finally, we compared social network structure across groups of different sizes. Groups of 10 spiders experienced more bacterial transmission events compared to groups of 30 spiders, regardless of groups' behavioural composition. Groups containing only one bold spider experienced the lowest levels of bacterial transmission regardless of group size. We found no evidence for the traits of the primary case influencing any transmission dynamics. In a second experiment, bacteria were transmitted to more individuals in experimentally induced star networks than in daisy-chains, on which transmission never exceeded three steps. In both experimental network types, transmission success depended jointly on the behavioural traits of the interacting individuals; however, the behavioural traits of the primary case were only important for transmission on star networks. Larger social groups exhibited lower interaction density (i.e. had a low ratio of observed to possible connections) and were more modular, i.e. they had more connections between nodes within a subgroup and fewer connections across subgroups. Thus, larger groups may restrict transmission by forming fewer interactions and by isolating subgroups that interacted with the primary case. These findings suggest that accounting for the traits of single exposed hosts has less power in predicting transmission

Combining protein sequence, structure, and dynamics: A novel approach for functional evolution analysis of PAS domain superfamily.

Science.gov (United States)

Dong, Zheng; Zhou, Hongyu; Tao, Peng

2018-02-01

PAS domains are widespread in archaea, bacteria, and eukaryota, and play important roles in various functions. In this study, we aim to explore functional evolutionary relationship among proteins in the PAS domain superfamily in view of the sequence-structure-dynamics-function relationship. We collected protein sequences and crystal structure data from RCSB Protein Data Bank of the PAS domain superfamily belonging to three biological functions (nucleotide binding, photoreceptor activity, and transferase activity). Protein sequences were aligned and then used to select sequence-conserved residues and build phylogenetic tree. Three-dimensional structure alignment was also applied to obtain structure-conserved residues. The protein dynamics were analyzed using elastic network model (ENM) and validated by molecular dynamics (MD) simulation. The result showed that the proteins with same function could be grouped by sequence similarity, and proteins in different functional groups displayed statistically significant difference in their vibrational patterns. Interestingly, in all three functional groups, conserved amino acid residues identified by sequence and structure conservation analysis generally have a lower fluctuation than other residues. In addition, the fluctuation of conserved residues in each biological function group was strongly correlated with the corresponding biological function. This research suggested a direct connection in which the protein sequences were related to various functions through structural dynamics. This is a new attempt to delineate functional evolution of proteins using the integrated information of sequence, structure, and dynamics. © 2017 The Protein Society.

Nonlinear analysis of dynamic signature

Science.gov (United States)

Rashidi, S.; Fallah, A.; Towhidkhah, F.

2013-12-01

Signature is a long trained motor skill resulting in well combination of segments like strokes and loops. It is a physical manifestation of complex motor processes. The problem, generally stated, is that how relative simplicity in behavior emerges from considerable complexity of perception-action system that produces behavior within an infinitely variable biomechanical and environmental context. To solve this problem, we present evidences which indicate that motor control dynamic in signing process is a chaotic process. This chaotic dynamic may explain a richer array of time series behavior in motor skill of signature. Nonlinear analysis is a powerful approach and suitable tool which seeks for characterizing dynamical systems through concepts such as fractal dimension and Lyapunov exponent. As a result, they can be analyzed in both horizontal and vertical for time series of position and velocity. We observed from the results that noninteger values for the correlation dimension indicates low dimensional deterministic dynamics. This result could be confirmed by using surrogate data tests. We have also used time series to calculate the largest Lyapunov exponent and obtain a positive value. These results constitute significant evidence that signature data are outcome of chaos in a nonlinear dynamical system of motor control.

Simplified Dynamic Analysis of Grinders Spindle Node

Science.gov (United States)

Demec, Peter

2014-12-01

The contribution deals with the simplified dynamic analysis of surface grinding machine spindle node. Dynamic analysis is based on the use of the transfer matrix method, which is essentially a matrix form of method of initial parameters. The advantage of the described method, despite the seemingly complex mathematical apparatus, is primarily, that it does not require for solve the problem of costly commercial software using finite element method. All calculations can be made for example in MS Excel, which is advantageous especially in the initial stages of constructing of spindle node for the rapid assessment of the suitability its design. After detailing the entire structure of spindle node is then also necessary to perform the refined dynamic analysis in the environment of FEM, which it requires the necessary skills and experience and it is therefore economically difficult. This work was developed within grant project KEGA No. 023TUKE-4/2012 Creation of a comprehensive educational - teaching material for the article Production technique using a combination of traditional and modern information technology and e-learning.

An analysis of 99mTc-DTPA renal dynamic imaging in patients with diabetes mellitus

International Nuclear Information System (INIS)

Cao Guoxiang; Zhang Yongxue

2000-01-01

To investigate the regularity of renal dynamic imaging in the various courses of diabetes mellitus, and then to provide the important evidence variety for diagnosis and treatment. The data of renal dynamic imaging was analyzed on 276 kidneys of 40 normal and 98 diabetic patients, and according to course of disease, the diabetic patients was divided into three groups: ≤1 year, 1-5 year and ≥5 year respectively. Based upon was grouped 99m Tc-DTPA renal dynamic imaging and others, the renal functions into normal, approximately normal, I, II and III injury respectively, and the statistics and analysis of these data were carried out. The extent of renal function injury was related to the course of disease significantly, and it showed that the longer the course, the heavier the damage of renal function, and there was a significant difference between them (P 99m Tc-DTPA renal dynamic imaging can effectively evaluate the extent of renal functions injury and was also valuable for the clinical. Also, the study indicated that in diabetic patients susceptible to urinary tract infection could aggravate the injury of renal function

Scheduling with Group Dynamics: a Multi-Robot Task Allocation Algorithm based on Vacancy Chains

National Research Council Canada - National Science Library

Dahl, Torbjorn S; Mataric, Maja J; Sukhatme, Gaurav S

2002-01-01

.... We present a multi-robot task allocation algorithm that is sensitive to group dynamics. Our algorithm is based on vacancy chains, a resource distribution process common in human and animal societies...

Group Dynamics as a Critical Component of Successful Space Exploration: Conceptual Theory and Insights from the Biosphere 2 Closure Experiment

Science.gov (United States)

Nelson, Mark; Allen, John P.

As space exploration and eventually habitation achieves longer durations, successfully managing group dynamics of small, physically isolated groups will become vital. The paper summarizes important underlying research and conceptual theory and how these manifested in a well-documented example: the closure experiments of Biosphere 2. Key research breakthroughs in discerning the operation of small human groups comes from the pioneering work of W.R. Bion. He discovered two competing modalities of behavior. The first is the “task-oriented” or work group governed by shared acceptance of goals, reality-thinking in relation to time, resources and rational, and intelligent management of challenges presented. The opposing, usually unconscious, modality is what Bion called the “basic-assumption” group and alternates between three “group animal” groups: dependency/kill the leader; fight/flight and pairing. If not dealt with, these dynamics work to undermine and defeat the conscious task group’s goal achievement. The paper discusses crew training and selection, various approaches to structuring the work and hierarchy of the group, the importance of contact with a larger population through electronic communication and dealing with the “us-them” syndrome frequently observed between crew and Mission Control. The experience of the first two year closure of Biosphere 2 is drawn on in new ways to illustrate vicissitudes and management of group dynamics especially as both the inside team of biospherians and key members of Mission Control had training in working with group dynamics. Insights from that experience may help mission planning so that future groups in space cope successfully with inherent group dynamics challenges that arise.

A generalized Wigner function for quantum systems with the SU(2) dynamical symmetry group

International Nuclear Information System (INIS)

Klimov, A B; Romero, J L

2008-01-01

We introduce a Wigner-like quasidistribution function to describe quantum systems with the SU(2) dynamic symmetry group. This function is defined in a three-dimensional group manifold and can be used to represent the states defined in several SU(2) invariant subspaces. The explicit differential Moyal-like form of the star product is found and analyzed in the semiclassical limit

Enabling dynamic network analysis through visualization in TVNViewer

Directory of Open Access Journals (Sweden)

Curtis Ross E

2012-08-01

Full Text Available Abstract Background Many biological processes are context-dependent or temporally specific. As a result, relationships between molecular constituents evolve across time and environments. While cutting-edge machine learning techniques can recover these networks, exploring and interpreting the rewiring behavior is challenging. Information visualization shines in this type of exploratory analysis, motivating the development ofTVNViewer (http://sailing.cs.cmu.edu/tvnviewer, a visualization tool for dynamic network analysis. Results In this paper, we demonstrate visualization techniques for dynamic network analysis by using TVNViewer to analyze yeast cell cycle and breast cancer progression datasets. Conclusions TVNViewer is a powerful new visualization tool for the analysis of biological networks that change across time or space.

Enabling dynamic network analysis through visualization in TVNViewer

Science.gov (United States)

2012-01-01

Background Many biological processes are context-dependent or temporally specific. As a result, relationships between molecular constituents evolve across time and environments. While cutting-edge machine learning techniques can recover these networks, exploring and interpreting the rewiring behavior is challenging. Information visualization shines in this type of exploratory analysis, motivating the development ofTVNViewer (http://sailing.cs.cmu.edu/tvnviewer), a visualization tool for dynamic network analysis. Results In this paper, we demonstrate visualization techniques for dynamic network analysis by using TVNViewer to analyze yeast cell cycle and breast cancer progression datasets. Conclusions TVNViewer is a powerful new visualization tool for the analysis of biological networks that change across time or space. PMID:22897913

Aperiodic dynamics in a deterministic adaptive network model of attitude formation in social groups

Science.gov (United States)

Ward, Jonathan A.; Grindrod, Peter

2014-07-01

Adaptive network models, in which node states and network topology coevolve, arise naturally in models of social dynamics that incorporate homophily and social influence. Homophily relates the similarity between pairs of nodes' states to their network coupling strength, whilst social influence causes coupled nodes' states to convergence. In this paper we propose a deterministic adaptive network model of attitude formation in social groups that includes these effects, and in which the attitudinal dynamics are represented by an activato-inhibitor process. We illustrate that consensus, corresponding to all nodes adopting the same attitudinal state and being fully connected, may destabilise via Turing instability, giving rise to aperiodic dynamics with sensitive dependence on initial conditions. These aperiodic dynamics correspond to the formation and dissolution of sub-groups that adopt contrasting attitudes. We discuss our findings in the context of cultural polarisation phenomena. Social influence. This reflects the fact that people tend to modify their behaviour and attitudes in response to the opinions of others [22-26]. We model social influence via diffusion: agents adjust their state according to a weighted sum (dictated by the evolving network) of the differences between their state and the states of their neighbours. Homophily. This relates the similarity of individuals' states to their frequency and strength of interaction [27]. Thus in our model, homophily drives the evolution of the weighted ‘social' network. A precise formulation of our model is given in Section 2. Social influence and homophily underpin models of social dynamics [21], which cover a wide range of sociological phenomena, including the diffusion of innovations [28-32], complex contagions [33-36], collective action [37-39], opinion dynamics [19,20,40,10,11,13,15,41,16], the emergence of social norms [42-44], group stability [45], social differentiation [46] and, of particular relevance

Statistical analysis of dynamic parameters of the core

International Nuclear Information System (INIS)

Ionov, V.S.

2007-01-01

The transients of various types were investigated for the cores of zero power critical facilities in RRC KI and NPP. Dynamic parameters of neutron transients were explored by tool statistical analysis. Its have sufficient duration, few channels for currents of chambers and reactivity and also some channels for technological parameters. On these values the inverse period. reactivity, lifetime of neutrons, reactivity coefficients and some effects of a reactivity are determinate, and on the values were restored values of measured dynamic parameters as result of the analysis. The mathematical means of statistical analysis were used: approximation(A), filtration (F), rejection (R), estimation of parameters of descriptive statistic (DSP), correlation performances (kk), regression analysis(KP), the prognosis (P), statistician criteria (SC). The calculation procedures were realized by computer language MATLAB. The reasons of methodical and statistical errors are submitted: inadequacy of model operation, precision neutron-physical parameters, features of registered processes, used mathematical model in reactivity meters, technique of processing for registered data etc. Examples of results of statistical analysis. Problems of validity of the methods used for definition and certification of values of statistical parameters and dynamic characteristics are considered (Authors)

Making instruction and assessment responsive to diverse students' progress: group-administered dynamic assessment in teaching mathematics.

Science.gov (United States)

Jeltova, Ida; Birney, Damian; Fredine, Nancy; Jarvin, Linda; Sternberg, Robert J; Grigorenko, Elena L

2011-01-01

This study entailed a 3 (instructional intervention) × 2 (assessment-type) between-subjects experimental design employing a pretest-intervention-posttest methodology. The instructional interventions were administered between subjects in three conditions: (a) dynamic instruction, (b) triarchic or theory of successful intelligence-control instruction, and (c) standard-control instruction. The assessment-type consisted between subjects of either (a) a group-administered dynamic posttest or (b) the same group-administered posttest interspersed with a control filler activity. Performance in different mathematics content areas taught in fourth grade was investigated. In total, 1,332 students and 63 classroom teachers in 24 schools across six school districts participated in the study. The results indicate the advantages of using dynamic instruction and assessment in regular classrooms while teaching mathematics, especially when the student body is highly ethnically diverse.

The manufacture of ZPR dynamic parameter analysis system

International Nuclear Information System (INIS)

Chen Huaide

1992-01-01

Under the guiding ideology of synthesize to blaze new trails. Utilizing the combination of various technologies, such as modern nuclear detective technology, electronic technology, computer technology, reactor physics experimental technology, and system technology etc., a new type ZPR dynamic parameter analysis system is manufactured. It consists of neutron detector sets, which including BF 3 proportional counter, 3 He proportional counter, fission chamber etc., detector bias supply, amplifier and discriminator, counter and multiplexer, micro-computer-based multifunction multichannel analyzer and system management software etc. The system has been checked and accepted by the group of experts in 1991. After the discussion, it is thought, that the specifications of the system are satisfactory and surpassed the requirement in advance, the overall design is thoughtful, the manufacture technology attains the advanced level of China

The manufacture of ZPR dynamic parameter analysis system

Energy Technology Data Exchange (ETDEWEB)

Huaide, Chen

1993-12-31

Under the guiding ideology of synthesize to blaze new trails. Utilizing the combination of various technologies, such as modern nuclear detective technology, electronic technology, computer technology, reactor physics experimental technology, and system technology etc., a new type ZPR dynamic parameter analysis system is manufactured. It consists of neutron detector sets, which including BF{sub 3} proportional counter, {sup 3}He proportional counter, fission chamber etc., detector bias supply, amplifier and discriminator, counter and multiplexer, micro-computer-based multifunction multichannel analyzer and system management software etc. The system has been checked and accepted by the group of experts in 1991. After the discussion, it is thought, that the specifications of the system are satisfactory and surpassed the requirement in advance, the overall design is thoughtful, the manufacture technology attains the advanced level of China

Integrating atomistic molecular dynamics simulations, experiments and network analysis to study protein dynamics: strength in unity

Directory of Open Access Journals (Sweden)

Elena ePapaleo

2015-05-01

Full Text Available In the last years, we have been observing remarkable improvements in the field of protein dynamics. Indeed, we can now study protein dynamics in atomistic details over several timescales with a rich portfolio of experimental and computational techniques. On one side, this provides us with the possibility to validate simulation methods and physical models against a broad range of experimental observables. On the other side, it also allows a complementary and comprehensive view on protein structure and dynamics. What is needed now is a better understanding of the link between the dynamic properties that we observe and the functional properties of these important cellular machines. To make progresses in this direction, we need to improve the physical models used to describe proteins and solvent in molecular dynamics, as well as to strengthen the integration of experiments and simulations to overcome their own limitations. Moreover, now that we have the means to study protein dynamics in great details, we need new tools to understand the information embedded in the protein ensembles and in their dynamic signature. With this aim in mind, we should enrich the current tools for analysis of biomolecular simulations with attention to the effects that can be propagated over long distances and are often associated to important biological functions. In this context, approaches inspired by network analysis can make an important contribution to the analysis of molecular dynamics simulations.

Combustion Dynamics Facility: April 1990 workshop working group reports

Energy Technology Data Exchange (ETDEWEB)

Kung, A.H.; Lee, Y.T.

1990-04-01

This document summarizes results from a workshop held April 5--7, 1990, on the proposed Combustion Dynamics Facility (CDF). The workshop was hosted by the Lawrence Berkeley Laboratory (LBL) and Sandia National Laboratories (SNL) to provide an opportunity for potential users to learn about the proposed experimental and computational facilities, to discuss the science that could be conducted with such facilities, and to offer suggestions as to how the specifications and design of the proposed facilities might be further refined to address the most visionary scientific opportunities. Some 130 chemical physicists, combustion chemists, and specialists in UV synchrotron radiation sources and free-electron lasers (more than half of whom were from institutions other than LBL and SNL) attended the five plenary sessions and participated in one or more of the nine parallel working group sessions. Seven of these sessions were devoted to broadening and strengthening the scope of CDF scientific opportunities and to detail the experimental facilities required to realize these opportunities. Two technical working group sessions addressed the design and proposed performance of two of the major CDF experimental facilities. These working groups and their chairpersons are listed below. A full listing of the attendees of the workshop is given in Appendix A. 1 tab.

Visibility graph analysis on heartbeat dynamics of meditation training

Science.gov (United States)

Jiang, Sen; Bian, Chunhua; Ning, Xinbao; Ma, Qianli D. Y.

2013-06-01

We apply the visibility graph analysis to human heartbeat dynamics by constructing the complex networks of heartbeat interval time series and investigating the statistical properties of the network before and during chi and yoga meditation. The experiment results show that visibility graph analysis can reveal the dynamical changes caused by meditation training manifested as regular heartbeat, which is closely related to the adjustment of autonomous neural system, and visibility graph analysis is effective to evaluate the effect of meditation.

Information-theoretic analysis of the dynamics of an executable biological model.

Directory of Open Access Journals (Sweden)

Avital Sadot

Full Text Available To facilitate analysis and understanding of biological systems, large-scale data are often integrated into models using a variety of mathematical and computational approaches. Such models describe the dynamics of the biological system and can be used to study the changes in the state of the system over time. For many model classes, such as discrete or continuous dynamical systems, there exist appropriate frameworks and tools for analyzing system dynamics. However, the heterogeneous information that encodes and bridges molecular and cellular dynamics, inherent to fine-grained molecular simulation models, presents significant challenges to the study of system dynamics. In this paper, we present an algorithmic information theory based approach for the analysis and interpretation of the dynamics of such executable models of biological systems. We apply a normalized compression distance (NCD analysis to the state representations of a model that simulates the immune decision making and immune cell behavior. We show that this analysis successfully captures the essential information in the dynamics of the system, which results from a variety of events including proliferation, differentiation, or perturbations such as gene knock-outs. We demonstrate that this approach can be used for the analysis of executable models, regardless of the modeling framework, and for making experimentally quantifiable predictions.

Application of dynamic response analysis to JET heat pulse data

International Nuclear Information System (INIS)

Griguoli, A.; Sips, A.C.C.

1993-09-01

The plasma dynamic response can be used to study transport processes in a tokamak plasma. A method has been developed for the application of dynamic response analysis to study perturbations away from the plasma equilibrium. In this report perturbations on the electron temperature following a sawtooth collapse in the center of the plasma are considered. The method has been used to find mathematical description of a series of heat pulses at the Joint European Torus project (JET). From the plasma dynamic response, the time constants which characterise the heat pulse are obtained. These time constants are compared to the transport coefficients found in previous analysis of the JET heat pulse data. Various methods are discussed for applying dynamic response analysis to JET heat pulse data. (author)

A Dynamic Network Approach to the Assessment of Terrorist Groups and the Impact of Alternative Courses of Action

National Research Council Canada - National Science Library

Carley, Kathleen M

2006-01-01

Dynamic network analysis (DNA) is an emergent field centered on the collection, analysis, understanding and prediction of dynamic relations among various entities such as actors, events and resources and the impact...

Flight Dynamics Analysis Branch 2005 Technical Highlights

Science.gov (United States)

2005-01-01

This report summarizes the major activities and accomplishments carried out by the Flight Dynamics Analysis Branch (FDAB), Code 595, in support of flight projects and technology development initiatives in Fiscal Year (FY) 2005. The report is intended to serve as a summary of the type of support carried out by the FDAB, as well as a concise reference of key accomplishments and mission experience derived from the various mission support roles. The primary focus of the FDAB is to provide expertise in the disciplines of flight dynamics including spacecraft navigation (autonomous and ground based); spacecraft trajectory design and maneuver planning; attitude analysis; attitude determination and sensor calibration; and attitude control subsystem (ACS) analysis and design. The FDAB currently provides support for missions and technology development projects involving NASA, other government agencies, academia, and private industry.

Sensitivity analysis and optimization of system dynamics models : Regression analysis and statistical design of experiments

NARCIS (Netherlands)

Kleijnen, J.P.C.

1995-01-01

This tutorial discusses what-if analysis and optimization of System Dynamics models. These problems are solved, using the statistical techniques of regression analysis and design of experiments (DOE). These issues are illustrated by applying the statistical techniques to a System Dynamics model for

Safety-oriented global analysis of reactor dynamics

International Nuclear Information System (INIS)

Belhadj, M.; Aldemir, T.

1992-01-01

It is well known that the asymptotic solutions of the non-linear systems encountered in reactor dynamics can change from stable to periodic or from periodic to chaotic with a very small change in system parameters and/or initial conditions. In that respect, determination of the domains of attraction (DOAs) in the state-space that contains the asymptotic solutions and the identification of the basins of attraction (BOAs) and lead to these DOAs usually requires a global analysis of reactor dynamics (as opposed to a local analysis through perturbation theory). From the standpoint of safety, the DOAs indicate whether the reactor behavior remains within the imposed constraints or not, and the BOAs show which initial conditions lead to safe operation. Due to the lack of a general theory, often the only feasible method for the global analysis of nonlinear systems is the direct integration of governing equations. However, direct integration can be computationally prohibitive, particularly if there is uncertainty on the values of the system parameters to be used in the analysis, and/or asymptotic system behavior is chaotic. In a recent study, a global analysis algorithm was presented to determine the structure of DOAs (and their probability distribution when there is uncertainty on the system parameters) more quickly than by direct integration. This paper shows how the new algorithm can be expanded to determine the BOAs of reactor dynamics equations as well as their DOAs

Dynamical renormalization group approach to relaxation in quantum field theory

International Nuclear Information System (INIS)

Boyanovsky, D.; Vega, H.J. de

2003-01-01

The real time evolution and relaxation of expectation values of quantum fields and of quantum states are computed as initial value problems by implementing the dynamical renormalization group (DRG). Linear response is invoked to set up the renormalized initial value problem to study the dynamics of the expectation value of quantum fields. The perturbative solution of the equations of motion for the field expectation values of quantum fields as well as the evolution of quantum states features secular terms, namely terms that grow in time and invalidate the perturbative expansion for late times. The DRG provides a consistent framework to resum these secular terms and yields a uniform asymptotic expansion at long times. Several relevant cases are studied in detail, including those of threshold infrared divergences which appear in gauge theories at finite temperature and lead to anomalous relaxation. In these cases the DRG is shown to provide a resummation akin to Bloch-Nordsieck but directly in real time and that goes beyond the scope of Bloch-Nordsieck and Dyson resummations. The nature of the resummation program is discussed in several examples. The DRG provides a framework that is consistent, systematic, and easy to implement to study the non-equilibrium relaxational dynamics directly in real time that does not rely on the concept of quasiparticle widths

A secure effective dynamic group password-based authenticated key agreement scheme for the integrated EPR information system

Directory of Open Access Journals (Sweden)

Vanga Odelu

2016-01-01

Full Text Available With the rapid growth of the Internet, a lot of electronic patient records (EPRs have been developed for e-medicine systems. The security and privacy issues of EPRs are important for the patients in order to understand how the hospitals control the use of their personal information, such as name, address, e-mail, medical records, etc. of a particular patient. Recently, Lee et al. proposed a simple group password-based authenticated key agreement protocol for the integrated EPR information system (SGPAKE. However, in this paper, we show that Lee et al.’s protocol is vulnerable to the off-line weak password guessing attack and as a result, their scheme does not provide users’ privacy. To withstand this security weakness found in Lee et al.’s scheme, we aim to propose an effective dynamic group password-based authenticated key exchange scheme for the integrated EPR information system, which retains the original merits of Lee et al.’s scheme. Through the informal and formal security analysis, we show that our scheme provides users’ privacy, perfect forward security and known-key security, and also protects online and offline password guessing attacks. Furthermore, our scheme efficiently supports the dynamic group password-based authenticated key agreement for the integrated EPR information system. In addition, we simulate our scheme for the formal security verification using the widely-accepted AVISPA (Automated Validation of Internet Security Protocols and Applications tool and show that our scheme is secure against passive and active attacks.

Discrete and continuous time dynamic mean-variance analysis

OpenAIRE

Reiss, Ariane

1999-01-01

Contrary to static mean-variance analysis, very few papers have dealt with dynamic mean-variance analysis. Here, the mean-variance efficient self-financing portfolio strategy is derived for n risky assets in discrete and continuous time. In the discrete setting, the resulting portfolio is mean-variance efficient in a dynamic sense. It is shown that the optimal strategy for n risky assets may be dominated if the expected terminal wealth is constrained to exactly attain a certain goal instead o...

Integrated framework for dynamic safety analysis

International Nuclear Information System (INIS)

Kim, Tae Wan; Karanki, Durga R.

2012-01-01

In the conventional PSA (Probabilistic Safety Assessment), detailed plant simulations by independent thermal hydraulic (TH) codes are used in the development of accident sequence models. Typical accidents in a NPP involve complex interactions among process, safety systems, and operator actions. As independent TH codes do not have the models of operator actions and full safety systems, they cannot literally simulate the integrated and dynamic interactions of process, safety systems, and operator responses. Offline simulation with pre decided states and time delays may not model the accident sequences properly. Moreover, when stochastic variability in responses of accident models is considered, defining all the combinations for simulations will be cumbersome task. To overcome some of these limitations of conventional safety analysis approach, TH models are coupled with the stochastic models in the dynamic event tree (DET) framework, which provides flexibility to model the integrated response due to better communication as all the accident elements are in the same model. The advantages of this framework also include: Realistic modeling in dynamic scenarios, comprehensive results, integrated approach (both deterministic and probabilistic models), and support for HRA (Human Reliability Analysis)

Dynamic analysis of solid propellant grains subjected to ignition pressurization loading

Science.gov (United States)

Chyuan, Shiang-Woei

2003-11-01

Traditionally, the transient analysis of solid propellant grains subjected to ignition pressurization loading was not considered, and quasi-elastic-static analysis was widely adopted for structural integrity because the analytical task gets simplified. But it does not mean that the dynamic effect is not useful and could be neglected arbitrarily, and this effect usually plays a very important role for some critical design. In order to simulate the dynamic response for solid rocket motor, a transient finite element model, accompanied by concepts of time-temperature shift principle, reduced integration and thermorheologically simple material assumption, was used. For studying the dynamic response, diverse ignition pressurization loading cases were used and investigated in the present paper. Results show that the dynamic effect is important for structural integrity of solid propellant grains under ignition pressurization loading. Comparing the effective stress of transient analysis and of quasi-elastic-static analysis, one can see that there is an obvious difference between them because of the dynamic effect. From the work of quasi-elastic-static and transient analyses, the dynamic analysis highlighted several areas of interest and a more accurate and reasonable result could be obtained for the engineer.

A renormalization group scaling analysis for compressible two-phase flow

International Nuclear Information System (INIS)

Chen, Y.; Deng, Y.; Glimm, J.; Li, G.; Zhang, Q.; Sharp, D.H.

1993-01-01

Computational solutions to the Rayleigh--Taylor fluid mixing problem, as modeled by the two-fluid two-dimensional Euler equations, are presented. Data from these solutions are analyzed from the point of view of Reynolds averaged equations, using scaling laws derived from a renormalization group analysis. The computations, carried out with the front tracking method on an Intel iPSC/860, are highly resolved and statistical convergence of ensemble averages is achieved. The computations are consistent with the experimentally observed growth rates for nearly incompressible flows. The dynamics of the interior portion of the mixing zone is simplified by the use of scaling variables. The size of the mixing zone suggests fixed-point behavior. The profile of statistical quantities within the mixing zone exhibit self-similarity under fixed-point scaling to a limited degree. The effect of compressibility is also examined. It is found that, for even moderate compressibility, the growth rates fail to satisfy universal scaling, and moreover, increase significantly with increasing compressibility. The growth rates predicted from a renormalization group fixed-point model are in a reasonable agreement with the results of the exact numerical simulations, even for flows outside of the incompressible limit

Dynamic data analysis modeling data with differential equations

CERN Document Server

Ramsay, James

2017-01-01

This text focuses on the use of smoothing methods for developing and estimating differential equations following recent developments in functional data analysis and building on techniques described in Ramsay and Silverman (2005) Functional Data Analysis. The central concept of a dynamical system as a buffer that translates sudden changes in input into smooth controlled output responses has led to applications of previously analyzed data, opening up entirely new opportunities for dynamical systems. The technical level has been kept low so that those with little or no exposure to differential equations as modeling objects can be brought into this data analysis landscape. There are already many texts on the mathematical properties of ordinary differential equations, or dynamic models, and there is a large literature distributed over many fields on models for real world processes consisting of differential equations. However, a researcher interested in fitting such a model to data, or a statistician interested in...

Group dynamics of zebra and wildebeest in a woodland savanna: effects of predation risk and habitat density.

Directory of Open Access Journals (Sweden)

Maria Thaker

Full Text Available BACKGROUND: Group dynamics of gregarious ungulates in the grasslands of the African savanna have been well studied, but the trade-offs that affect grouping of these ungulates in woodland habitats or dense vegetation are less well understood. We examined the landscape-level distribution of groups of blue wildebeest, Connochaetes taurinus, and Burchell's zebra, Equus burchelli, in a predominantly woodland area (Karongwe Game Reserve, South Africa; KGR to test the hypothesis that group dynamics are a function of minimizing predation risk from their primary predator, lion, Panthera leo. METHODOLOGY/PRINCIPAL FINDINGS: Using generalized linear models, we examined the relative importance of habitat type (differing in vegetation density, probability of encountering lion (based on utilization distribution of all individual lions in the reserve, and season in predicting group size and composition. We found that only in open scrub habitat, group size for both ungulate species increased with the probability of encountering lion. Group composition differed between the two species and was driven by habitat selection as well as predation risk. For both species, composition of groups was, however, dominated by males in open scrub habitats, irrespective of the probability of encountering lion. CONCLUSIONS/SIGNIFICANCE: Distribution patterns of wildebeest and zebra groups at the landscape level directly support the theoretical and empirical evidence from a range of taxa predicting that grouping is favored in open habitats and when predation risk is high. Group composition reflected species-specific social, physiological and foraging constraints, as well as the importance of predation risk. Avoidance of high resource open scrub habitat by females can lead to loss of foraging opportunities, which can be particularly costly in areas such as KGR, where this resource is limited. Thus, landscape-level grouping dynamics are species specific and particular to the

Dynamic Error Analysis Method for Vibration Shape Reconstruction of Smart FBG Plate Structure

Directory of Open Access Journals (Sweden)

Hesheng Zhang

2016-01-01

Full Text Available Shape reconstruction of aerospace plate structure is an important issue for safe operation of aerospace vehicles. One way to achieve such reconstruction is by constructing smart fiber Bragg grating (FBG plate structure with discrete distributed FBG sensor arrays using reconstruction algorithms in which error analysis of reconstruction algorithm is a key link. Considering that traditional error analysis methods can only deal with static data, a new dynamic data error analysis method are proposed based on LMS algorithm for shape reconstruction of smart FBG plate structure. Firstly, smart FBG structure and orthogonal curved network based reconstruction method is introduced. Then, a dynamic error analysis model is proposed for dynamic reconstruction error analysis. Thirdly, the parameter identification is done for the proposed dynamic error analysis model based on least mean square (LMS algorithm. Finally, an experimental verification platform is constructed and experimental dynamic reconstruction analysis is done. Experimental results show that the dynamic characteristics of the reconstruction performance for plate structure can be obtained accurately based on the proposed dynamic error analysis method. The proposed method can also be used for other data acquisition systems and data processing systems as a general error analysis method.

Student leadership in small group science inquiry

Science.gov (United States)

Oliveira, Alandeom W.; Boz, Umit; Broadwell, George A.; Sadler, Troy D.

2014-09-01

Background: Science educators have sought to structure collaborative inquiry learning through the assignment of static group roles. This structural approach to student grouping oversimplifies the complexities of peer collaboration and overlooks the highly dynamic nature of group activity. Purpose: This study addresses this issue of oversimplification of group dynamics by examining the social leadership structures that emerge in small student groups during science inquiry. Sample: Two small student groups investigating the burning of a candle under a jar participated in this study. Design and method: We used a mixed-method research approach that combined computational discourse analysis (computational quantification of social aspects of small group discussions) with microethnography (qualitative, in-depth examination of group discussions). Results: While in one group social leadership was decentralized (i.e., students shared control over topics and tasks), the second group was dominated by a male student (centralized social leadership). Further, decentralized social leadership was found to be paralleled by higher levels of student cognitive engagement. Conclusions: It is argued that computational discourse analysis can provide science educators with a powerful means of developing pedagogical models of collaborative science learning that take into account the emergent nature of group structures and highly fluid nature of student collaboration.

Masticatory biomechanics in the rabbit: a multi-body dynamics analysis.

Science.gov (United States)

Watson, Peter J; Gröning, Flora; Curtis, Neil; Fitton, Laura C; Herrel, Anthony; McCormack, Steven W; Fagan, Michael J

2014-10-06

Multi-body dynamics is a powerful engineering tool which is becoming increasingly popular for the simulation and analysis of skull biomechanics. This paper presents the first application of multi-body dynamics to analyse the biomechanics of the rabbit skull. A model has been constructed through the combination of manual dissection and three-dimensional imaging techniques (magnetic resonance imaging and micro-computed tomography). Individual muscles are represented with multiple layers, thus more accurately modelling muscle fibres with complex lines of action. Model validity was sought through comparing experimentally measured maximum incisor bite forces with those predicted by the model. Simulations of molar biting highlighted the ability of the masticatory system to alter recruitment of two muscle groups, in order to generate shearing or crushing movements. Molar shearing is capable of processing a food bolus in all three orthogonal directions, whereas molar crushing and incisor biting are predominately directed vertically. Simulations also show that the masticatory system is adapted to process foods through several cycles with low muscle activations, presumably in order to prevent rapidly fatiguing fast fibres during repeated chewing cycles. Our study demonstrates the usefulness of a validated multi-body dynamics model for investigating feeding biomechanics in the rabbit, and shows the potential for complementing and eventually reducing in vivo experiments.

Advantages of a Dynamic RGGG Method in Qualitative and Quantitative Analysis

International Nuclear Information System (INIS)

Shin, Seung Ki; Seong, Poong Hyun

2009-01-01

Various researches have been conducted in order to analyze dynamic interactions among components and process variables in nuclear power plants which cannot be handled by static reliability analysis methods such as conventional fault tree and event tree techniques. A dynamic reliability graph with general gates (RGGG) method was proposed for an intuitive modeling of dynamic systems and it enables one to easily analyze huge and complex systems. In this paper, advantages of the dynamic RGGG method are assessed through two stages: system modeling and quantitative analysis. And then a software tool for dynamic RGGG method is introduced and an application to a real dynamic system is accompanied

A microcosm of musical expression: II. Quantitative analysis of pianists' dynamics in the initial measures of Chopin's Etude in E major.

Science.gov (United States)

Repp, B H

1999-03-01

Patterns of expressive dynamics were measured in bars 1-5 of 115 commercially recorded performances of Chopin's Etude in E major, op. 10, No. 3. The grand average pattern (or dynamic profile) was representative of many performances and highly similar to the average dynamic profile of a group of advanced student performances, which suggests a widely shared central norm of expressive dynamics. The individual dynamic profiles were subjected to principal components analysis, which yielded Varimax-rotated components, each representing a different, nonstandard dynamic profile associated with a small subset of performances. Most performances had dynamic patterns resembling a mixture of several components, and no clustering of of performances into distinct groups was apparent. Some weak relationships of dynamic profiles with sociocultural variables were found, most notably a tendency of female pianists to exhibit a greater dynamic range in the melody. Within the melody, there were no significant relationships between expressive timing [Repp, J. Acoust. Soc. Am. 104, 1085-1100 (1998)] and expressive dynamics. These two important dimensions seemed to be controlled independently at this local level and thus offer the artist many degrees of freedom in giving a melody expressive shape.

On the influence of latency estimation on dynamic group communication using overlays

Science.gov (United States)

Vik, Knut-Helge; Griwodz, Carsten; Halvorsen, Pål

2009-01-01

Distributed interactive applications tend to have stringent latency requirements and some may have high bandwidth demands. Many of them have also very dynamic user groups for which all-to-all communication is needed. In online multiplayer games, for example, such groups are determined through region-of-interest management in the application. We have investigated a variety of group management approaches for overlay networks in earlier work and shown that several useful tree heuristics exist. However, these heuristics require full knowledge of all overlay link latencies. Since this is not scalable, we investigate the effects that latency estimation techqniues have ton the quality of overlay tree constructions. We do this by evaluating one example of our group management approaches in Planetlab and examing how latency estimation techqniues influence their quality. Specifically, we investigate how two well-known latency estimation techniques, Vivaldi and Netvigator, affect the quality of tree building.

Supply risk analysis: applying system dynamics to the Colombian healthcare sector

Directory of Open Access Journals (Sweden)

Juan Pablo Zamora Aguas

2013-09-01

Full Text Available This paper addresses supply risk in the oncological medicine supply chain (SC in Colombia. A system dynamics model was developed for assessing supply risk impact on SC operation and performance. The costs of risk and logis-tics operation were evaluated in current conditions and in a risk mitigation scenario. The model was based on a systematic analysis of supply networks, mainly concerning the reduction of overall SC costs and improving service, quality and opportunity performance index. This article has resulted from research into SC risk management (SCRM carried out by the Universidad Nacional de Colombia’s SEPRO research group.

Ultrafast internal rotational dynamics of the azido group in (4S)-azidoproline: Chemical exchange 2DIR spectroscopic investigations

Energy Technology Data Exchange (ETDEWEB)

Lee, Kyung-Koo; Park, Kwang-Hee; Joo, Cheonik; Kwon, Hyeok-Jun; Han, Hogyu [Department of Chemistry, Korea University, Seoul 136-701 (Korea, Republic of); Ha, Jeong-Hyon [Multidimensional Spectroscopy Laboratory, Korea Basic Science Institute, Seoul 136-713 (Korea, Republic of); Park, Sungnam, E-mail: spark8@korea.ac.kr [Department of Chemistry, Korea University, Seoul 136-701 (Korea, Republic of); Multidimensional Spectroscopy Laboratory, Korea Basic Science Institute, Seoul 136-713 (Korea, Republic of); Cho, Minhaeng, E-mail: mcho@korea.ac.kr [Department of Chemistry, Korea University, Seoul 136-701 (Korea, Republic of); Multidimensional Spectroscopy Laboratory, Korea Basic Science Institute, Seoul 136-713 (Korea, Republic of); Research Institute for Natural Sciences, Korea University, Seoul 136-713 (Korea, Republic of)

2012-03-02

Graphical abstract: Internal rotational dynamics of the azido group in SA (Ac-(4S)-Azp-NHMe) was studied in real time by using ultrafast 2DIR spectroscopic method. The time constant of the internal rotation around the C{sup {gamma}}-N{sup {delta}} bond in SA was determined to be {tau}{sub ir} = 5.1 ps, which is found to be much faster than that around the C-C bond in ethane. Highlights: Black-Right-Pointing-Pointer Femtosecond two-dimensional IR spectroscopy of internal rotational dynamics. Black-Right-Pointing-Pointer Stereo-electronic effects of azido group in azido-derivatized proline peptide. Black-Right-Pointing-Pointer The timescale of the azido group internal rotation is about 5.1 ps. - Abstract: The azido group in 4-azidoproline (Azp) derivative, SA (Ac-(4S)-Azp-NHMe), can form an intramolecular electrostatic interaction with the backbone peptide in the s-trans and C{sup {gamma}}-endo conformations of SA. As a result, the azido group exists as two forms, bound and free, which are defined by the presence and absence of such interaction, respectively. The bound and free azido forms are spectrally resolved in the azido IR spectrum of SA in CHCl{sub 3}. Using the two-dimensional infrared (2DIR) and polarization-controlled IR pump-probe methods, we investigated the internal rotational and orientational relaxation dynamics of the azido group and determined the internal rotational time constant of the azido group to be 5.1 ps. The internal rotational motion is found to be responsible for the early part of the orientational relaxation of the azido group in SA. Thus, the femtosecond 2DIR spectroscopy is shown to be an ideal tool for studying ultrafast conformational dynamics of SA.

Residual mass considerations in modal analysis of large dynamic structural systems

International Nuclear Information System (INIS)

Shulman, J.S.; Day, J.P.

1991-01-01

Industry guidelines have specified that the seismic evaluation of Moderate and High Hazard Department of Energy (DOE) facilities be accomplished by use of dynamic analysis. The recommended approach is elastic response spectrum dynamic analysis to evaluate the elastic system demand on facility components. The application of modal response spectrum analysis to the seismic evaluation of nuclear facility structures, systems and equipment involves approximations due to limitations on the number of modes typically addressed in the complete dynamic solution. A simplified approach for achieving improved rigor in accounting for responses of the higher frequency modes in a modal response spectrum analysis is demonstrated

Dynamic characteristics analysis of deployable space structures considering joint clearance

Science.gov (United States)

Li, Tuanjie; Guo, Jian; Cao, Yuyan

2011-04-01

The clearance in joints influences the dynamic stability and the performance of deployable space structures (DSS). A virtual experimental modal analysis (VEMA) method is proposed to deal with the effects of joint clearance and link flexibility on the dynamic characteristics of the DSS in this paper. The focus is on the finite element modeling of the clearance joint, VEMA and the modal parameters identification of the DSS. The finite element models (FEM) of the clearance joint and the deployable structure are established in ANSYS. The transient dynamic analysis is conducted to provide the time history data of excitation and response for the VEMA. The fast Fourier transform (FFT) technique is used to transform the data from time domain to frequency domain. The frequency response function is calculated to identify the modal parameters of the deployable structure. Experimental verification is provided to indicate the VEMA method is both a cost and time efficient approach to obtain the dynamic characteristics of the DSS. Finally, we analyze the effects of clearance size and gravity on the dynamic characteristics of the DSS. The analysis results indicate that the joint clearance and gravity strongly influence the dynamic characteristics of the DSS.

Dynamic analysis of bulk-fill composites: Effect of food-simulating liquids.

Science.gov (United States)

Eweis, Ahmed Hesham; Yap, Adrian U-Jin; Yahya, Noor Azlin

2017-10-01

This study investigated the effect of food simulating liquids on visco-elastic properties of bulk-fill restoratives using dynamic mechanical analysis. One conventional composite (Filtek Z350 [FZ]), two bulk-fill composites (Filtek Bulk-fill [FB] and Tetric N Ceram [TN]) and a bulk-fill giomer (Beautifil-Bulk Restorative [BB]) were evaluated. Specimens (12 × 2 × 2mm) were fabricated using customized stainless steel molds. The specimens were light-cured, removed from their molds, finished, measured and randomly divided into six groups. The groups (n = 10) were conditioned in the following mediums for 7 days at 37°C: air (control), artificial saliva (SAGF), distilled water, 0.02N citric acid, heptane, 50% ethanol-water solution. Specimens were assessed using dynamic mechanical testing in flexural three-point bending mode and their respective mediums at 37°C and a frequency range of 0.1-10Hz. The distance between the supports were fixed at 10mm and an axial load of 5N was employed. Data for elastic modulus, viscous modulus and loss tangent were subjected to ANOVA/Tukey's tests at significance level p food-simulating liquids on the visco-elastic properties of bulk-fill composites was material and medium dependent. Copyright © 2017 Elsevier Ltd. All rights reserved.

Sensitization to group direction in the postgraduate training on Group-Analysis

Directory of Open Access Journals (Sweden)

Simone Bruschetta

2014-09-01

Full Text Available The psychodynamic training group here introduced is a part of the General Training on Group Analysis of the Centre of Palermo of COIRAG Postgraduate School on Analytic Psychotherapy. The training project’s aim, built for the class of the third year, develops a sensitization device which provide a unique set of aquarium. The aim of that methodological artifice is not to engage students on specific group management techniques, but to allow the whole class group to bring into play the complexity of relations, of which is necessary to have awareness in order to lead a group within an institutional context: The main clinical referents that we chose to monitor in this experience are the relationship between conductors and participants and the relationship between group, task and setting. The brief description of this methodology is also including the reporting of two "cases" treated in the course of training. Keywords: Group leadership, Founding dimension, Cultural themes 

Dynamics of bone healing after osteotomy with piezosurgery or conventional drilling - histomorphometrical, immunohistochemical, and molecular analysis.

Science.gov (United States)

Esteves, Jônatas Caldeira; Marcantonio, Elcio; de Souza Faloni, Ana Paula; Rocha, Fernanda Regina Godoy; Marcantonio, Rosemary Adriana; Wilk, Katarzyna; Intini, Giuseppe

2013-09-23

Piezosurgery is an osteotomy system used in medical and dental surgery. Many studies have proven clinical advantages of piezosurgery in terms of quality of cut, maneuverability, ease of use, and safety. However, few investigations have tested its superiority over the traditional osteotomy systems in terms of dynamics of bone healing. Therefore, the aim of this study was to evaluate the dynamics of bone healing after osteotomies with piezosurgery and to compare them with those associated to traditional bone drilling. One hundred and ten rats were divided into two groups with 55 animals each. The animals were anesthetized and the tibiae were surgically exposed to create defects 2 mm in diameter by using piezosurgery (Piezo group) and conventional drilling (Drill group). Animals were sacrificed at 3, 7, 14, 30 and 60 days post-surgery. Bone samples were collected and processed for histological, histomorphometrical, immunohistochemical, and molecular analysis. The histological analysis was performed at all time points (n = 8) whereas the histomorphometrical analysis was performed at 7, 14, 30 and 60 days post-surgery (n = 8). The immunolabeling was performed to detect Vascular Endothelial Growth Factor (VEGF), Caspase-3 (CAS-3), Osteoprotegerin (OPG), Receptor Activator of Nuclear Factor kappa-B Ligand (RANKL), and Osteocalcin (OC) at 3, 7, and 14 days (n = 3). For the molecular analysis, animals were sacrificed at 3, 7 and 14 days, total RNA was collected, and quantification of the expression of 21 genes related to BMP signaling, Wnt signaling, inflammation, osteogenenic and apoptotic pathways was performed by qRT-PCR (n = 5). Histologically and histomorphometrically, bone healing was similar in both groups with the exception of a slightly higher amount of newly formed bone observed at 30 days after piezosurgery (p piezosurgery are comparable to those observed with conventional drilling.

Modal analysis application for dynamic characterization of simple structures

International Nuclear Information System (INIS)

Pastorini, A.J.; Belinco, C.G.

1987-01-01

The knowledge of the dynamic characteristics of a structure helps to foresee the vibrating behaviour under operating conditions. The modal analysis techniques offer a method to perform the dynamic characterization of a studied structure from the vibration modes of such structure. A hammer provided with a loaded cell to excite a wide frequency band and accelerometer and, on the basis of a measurement of the transfer function at different points, various simple structures were given with a dynamic structures analysis (of the type of Fourier's rapidly transformation) and the results were compared with those obtained by other methods. Different fields where these techniques are applied, are also enumerated. (Author)

A double-loop adaptive sampling approach for sensitivity-free dynamic reliability analysis

International Nuclear Information System (INIS)

Wang, Zequn; Wang, Pingfeng

2015-01-01

Dynamic reliability measures reliability of an engineered system considering time-variant operation condition and component deterioration. Due to high computational costs, conducting dynamic reliability analysis at an early system design stage remains challenging. This paper presents a confidence-based meta-modeling approach, referred to as double-loop adaptive sampling (DLAS), for efficient sensitivity-free dynamic reliability analysis. The DLAS builds a Gaussian process (GP) model sequentially to approximate extreme system responses over time, so that Monte Carlo simulation (MCS) can be employed directly to estimate dynamic reliability. A generic confidence measure is developed to evaluate the accuracy of dynamic reliability estimation while using the MCS approach based on developed GP models. A double-loop adaptive sampling scheme is developed to efficiently update the GP model in a sequential manner, by considering system input variables and time concurrently in two sampling loops. The model updating process using the developed sampling scheme can be terminated once the user defined confidence target is satisfied. The developed DLAS approach eliminates computationally expensive sensitivity analysis process, thus substantially improves the efficiency of dynamic reliability analysis. Three case studies are used to demonstrate the efficacy of DLAS for dynamic reliability analysis. - Highlights: • Developed a novel adaptive sampling approach for dynamic reliability analysis. • POD Developed a new metric to quantify the accuracy of dynamic reliability estimation. • Developed a new sequential sampling scheme to efficiently update surrogate models. • Three case studies were used to demonstrate the efficacy of the new approach. • Case study results showed substantially enhanced efficiency with high accuracy

Dynamic fabric phase sorptive extraction for a group of pharmaceuticals and personal care products from environmental waters.

Science.gov (United States)

Lakade, Sameer S; Borrull, Francesc; Furton, Kenneth G; Kabir, Abuzar; Marcé, Rosa Maria; Fontanals, Núria

2016-07-22

This paper describes for the first time the use of a new extraction technique, based on fabric phase sorptive extraction (FPSE). This new mode proposes the extraction of the analytes in dynamic mode in order to reduce the extraction time. Dynamic fabric phase sorptive extraction (DFPSE) followed by liquid chromatography-tandem mass spectrometry was evaluated for the extraction of a group of pharmaceuticals and personal care products (PPCPs) from environmental water samples. Different parameters affecting the extraction were optimized and best conditions were achieved when 50mL of sample at pH 3 was passed through 3 disks and analytes retained were eluted with 10mL of ethyl acetate. The recoveries were higher than 60% for most of compounds with the exception of the most polar ones (between 8% and 38%). The analytical method was validated with environmental samples such as river water and effluent and influent wastewater, and good performance was obtained. The analysis of samples revealed the presence of some PPCPs at low ngL(-1) concentrations. Copyright © 2016 Elsevier B.V. All rights reserved.

Dynamic analysis of savings and economic growth in Nigeria ...

African Journals Online (AJOL)

Dynamic analysis of savings and economic growth in Nigeria. ... a trivariate dynamic Granger causality model with savings, economic growth and foreign ... It is recommended that in the short run, policies in Nigeria should be geared towards ...

Working group II report: Production and dynamics of high brightness beams

International Nuclear Information System (INIS)

Sheffield, R.L.

1996-01-01

This paper summarizes the main discussions of the Working Group on the Production and Dynamics of High Brightness Beams. The following topics are covered in this paper. Proposed new electron sources and needed research on existing sources is covered. The discussions on issues relating to the description of phase space on non-thermalized electron beam distributions and the theoretical modeling on non-thermalized electron beam distributions is presented. Finally, the present status of the theoretical modeling of beam transport in bends is given

Dynamical coupled-channel analysis at EBAC. (Excited Baryon Analysis Center)

International Nuclear Information System (INIS)

Lee, T.-S.H.; Thomas Jefferson National Accelerator Facility, Newport News, VA

2008-01-01

In this contribution, the author reports on the dynamical coupled-channels analysis being pursued at the Excited Baryon Analysis Center (EBAC) of Jefferson Laboratory. EBAC was established in January 2006. Its objective is to extract the parameters associated with the excited states (N*) of the nucleon from the world data of meson production reactions, and to also develop theoretical interpretations of the extracted N* parameters

Improving estimation of kinetic parameters in dynamic force spectroscopy using cluster analysis

Science.gov (United States)

Yen, Chi-Fu; Sivasankar, Sanjeevi

2018-03-01

Dynamic Force Spectroscopy (DFS) is a widely used technique to characterize the dissociation kinetics and interaction energy landscape of receptor-ligand complexes with single-molecule resolution. In an Atomic Force Microscope (AFM)-based DFS experiment, receptor-ligand complexes, sandwiched between an AFM tip and substrate, are ruptured at different stress rates by varying the speed at which the AFM-tip and substrate are pulled away from each other. The rupture events are grouped according to their pulling speeds, and the mean force and loading rate of each group are calculated. These data are subsequently fit to established models, and energy landscape parameters such as the intrinsic off-rate (koff) and the width of the potential energy barrier (xβ) are extracted. However, due to large uncertainties in determining mean forces and loading rates of the groups, errors in the estimated koff and xβ can be substantial. Here, we demonstrate that the accuracy of fitted parameters in a DFS experiment can be dramatically improved by sorting rupture events into groups using cluster analysis instead of sorting them according to their pulling speeds. We test different clustering algorithms including Gaussian mixture, logistic regression, and K-means clustering, under conditions that closely mimic DFS experiments. Using Monte Carlo simulations, we benchmark the performance of these clustering algorithms over a wide range of koff and xβ, under different levels of thermal noise, and as a function of both the number of unbinding events and the number of pulling speeds. Our results demonstrate that cluster analysis, particularly K-means clustering, is very effective in improving the accuracy of parameter estimation, particularly when the number of unbinding events are limited and not well separated into distinct groups. Cluster analysis is easy to implement, and our performance benchmarks serve as a guide in choosing an appropriate method for DFS data analysis.

A Group Creativity Support System for Dynamic Idea Evaluation

DEFF Research Database (Denmark)

Ulrich, Frank

2015-01-01

Idea evaluation is necessary in most modern organizations to identify the level of novelty and usefulness of new ideas. However, current idea evaluation research hinders creativity by primarily supporting convergent thinking (narrowing down ideas to a few tangible solutions), while divergent...... thinking (the development of wildly creative and novel thoughts patterns) is discounted. In this paper, this current view of idea evaluation is challenged through the development of a prototype that supports dynamic idea evaluation. The prototype uses knowledge created during evaluative processes...... to facilitate divergent thinking in a Group Creativity Support System (GCSS) designed from state-of-the-art research. The prototype is interpretively explored through a field experiment in a Danish IS research department. Consequently, the prototype demonstrates the ability to including divergent thinking...

Risk Analysis Group annual progress report 1984

International Nuclear Information System (INIS)

1985-06-01

The activities of the Risk Analysis Group at Risoe during 1984 are presented. These include descriptions in some detail of work on general development topics and risk analysis performed as contractor. (author)

An Analysis on a Dynamic Amplifier and Calibration Methods for a Pseudo-Differential Dynamic Comparator

Science.gov (United States)

Paik, Daehwa; Miyahara, Masaya; Matsuzawa, Akira

This paper analyzes a pseudo-differential dynamic comparator with a dynamic pre-amplifier. The transient gain of a dynamic pre-amplifier is derived and applied to equations of the thermal noise and the regeneration time of a comparator. This analysis enhances understanding of the roles of transistor's parameters in pre-amplifier's gain. Based on the calculated gain, two calibration methods are also analyzed. One is calibration of a load capacitance and the other is calibration of a bypass current. The analysis helps designers' estimation for the accuracy of calibration, dead-zone of a comparator with a calibration circuit, and the influence of PVT variation. The analyzed comparator uses 90-nm CMOS technology as an example and each estimation is compared with simulation results.

Robustness Analysis of Dynamic Watermarks

Directory of Open Access Journals (Sweden)

Ivan V. Nechta

2017-06-01

Full Text Available In this paper we consider previously known scheme of dynamic watermarks embedding (Ra- dix-n that is used for preventing illegal use of software. According to the scheme a watermark is dynamic linked data structure (graph, which is created in memory during program execution. Hidden data, such as information about author, can be represented in a different type of graph structure. This data can be extracted and demonstrated in judicial proceedings. This paper declared that the above mentioned scheme was previously one of the most reliable, has a number of features that allows an attacker to detect a stage of watermark construction in the program, and therefore it can be corrupted or deleted. The author of this article shows the weakness of Radix-N scheme, which consists in the fact that we can reveal dynamic data structures of a program by using information received from some API-functions hooker which catches function calls of dynamic memory allocation. One of these data structures is the watermark. Pointers on dynamically created objects (arrays, variables, class items, etc. of a program can be detected by content analysis of computer's RAM. Different dynamic objects in memory interconnected by pointers form dynamic data structures of a program such as lists, stacks, trees and other graphs (including the watermark. Our experiment shows that in the vast majority of cases the amount of data structure in programs is small, which increases probability of a successful attack. Also we present an algorithm for finding connected components of a graph with linear time-consuming in cases where the number of nodes is about 106. On the basis of the experimental findings the new watermarking scheme has been presented, which is resistant to the proposed attack. It is offered to use different graph structure representation of a watermark, where edges are implemented using unique signatures. Our scheme uses content encrypting of graph nodes (except signature

Describing pediatric dysphonia with nonlinear dynamic parameters

Science.gov (United States)

Meredith, Morgan L.; Theis, Shannon M.; McMurray, J. Scott; Zhang, Yu; Jiang, Jack J.

2008-01-01

Objective Nonlinear dynamic analysis has emerged as a reliable and objective tool for assessing voice disorders. However, it has only been tested on adult populations. In the present study, nonlinear dynamic analysis was applied to normal and dysphonic pediatric populations with the goal of collecting normative data. Jitter analysis was also applied in order to compare nonlinear dynamic and perturbation measures. This study’s findings will be useful in creating standards for the use of nonlinear dynamic analysis as a tool to describe dysphonia in the pediatric population. Methods The study included 38 pediatric subjects (23 children with dysphonia and 15 without). Recordings of sustained vowels were obtained from each subject and underwent nonlinear dynamic analysis and percent jitter analysis. The resulting correlation dimension (D2) and percent jitter values were compared across the two groups using t-tests set at a significance level of p = 0.05. Results It was shown that D2 values covary with the presence of pathology in children. D2 values were significantly higher in dysphonic children than in normal children (p = 0.002). Standard deviations indicated a higher level of variation in normal children’s D2 values than in dysphonic children’s D2 values. Jitter analysis showed markedly higher percent jitter in dysphonic children than in normal children (p = 0.025) and large standard deviations for both groups. Conclusion This study indicates that nonlinear dynamic analysis could be a viable tool for the detection and assessment of dysphonia in children. Further investigations and more normative data are needed to create standards for using nonlinear dynamic parameters for the clinical evaluation of pediatric dysphonia. PMID:18947887

Deliberations of working group 4: is there a new dynamics of dialogue and decision making?

International Nuclear Information System (INIS)

Kotra, J.P.

2000-01-01

The context for the working group's discussions was set by two papers: 'Lessons Learnt from the DECI project on different processes for Public Participation and Transparency in Decision making' and 'A New Siting Process in France for a URL in Granite: Lessons Learnt from the recently undertaken Consultation Mission (January-June 2000). As further evidence of change affecting the way waste managers and regulators communicate with their stakeholders, the group heard two presentations of specific case studies of waste disposal programmes encountering and responding to a new dynamic. (Belgium's revised approach to siting a low- and intermediate-level waste facility). Key factors in the new approach adopted by the Belgian government were the clear separation of ethical and technical choices, and the pursuit of partnerships with local municipalities. Many members of the working group were clearly impressed with the extent of trust and reliance placed on the decisions of the participating communities. Next, the group chairperson, discussed recent attempts by the US Nuclear Regulatory Commission to encourage greater public involvement in the development of new regulations for the proposed repository at Yucca Mountain. This was followed by an active and lively discussion among all members of the working group. Frequently the 'new dynamics of dialogue and decision making' were characterised as a shift from the traditional 'decide, announce and defend' approach for which the focus was almost exclusively on technical content, to one of 'engage, interact and co-operate' for which both technical content and quality of process are of comparable import to a constructive outcome. The session culminated with the identification of several possible means through which the FSC (Forum on Stakeholder Confidence) might contribute to and support member programmes as they endeavour to rise to the challenges posed y the new dynamics of dialogue. (author)

Nonlinear analysis of pupillary dynamics.

Science.gov (United States)

Onorati, Francesco; Mainardi, Luca Tommaso; Sirca, Fabiola; Russo, Vincenzo; Barbieri, Riccardo

2016-02-01

Pupil size reflects autonomic response to different environmental and behavioral stimuli, and its dynamics have been linked to other autonomic correlates such as cardiac and respiratory rhythms. The aim of this study is to assess the nonlinear characteristics of pupil size of 25 normal subjects who participated in a psychophysiological experimental protocol with four experimental conditions, namely “baseline”, “anger”, “joy”, and “sadness”. Nonlinear measures, such as sample entropy, correlation dimension, and largest Lyapunov exponent, were computed on reconstructed signals of spontaneous fluctuations of pupil dilation. Nonparametric statistical tests were performed on surrogate data to verify that the nonlinear measures are an intrinsic characteristic of the signals. We then developed and applied a piecewise linear regression model to detrended fluctuation analysis (DFA). Two joinpoints and three scaling intervals were identified: slope α0, at slow time scales, represents a persistent nonstationary long-range correlation, whereas α1 and α2, at middle and fast time scales, respectively, represent long-range power-law correlations, similarly to DFA applied to heart rate variability signals. Of the computed complexity measures, α0 showed statistically significant differences among experimental conditions (pnonlinear dynamics, (b) three well-defined and distinct long-memory processes exist at different time scales, and (c) autonomic stimulation is partially reflected in nonlinear dynamics. (c) autonomic stimulation is partially reflected in nonlinear dynamics.

The dynamic analysis facility at the Chalk River Nuclear Laboratories

International Nuclear Information System (INIS)

Argue, D.S.; Howatt, W.T.

1979-10-01

The Dynamic Analysis Facility at the Chalk River Nuclear Laboratories (CRNL) of Atomic Energy of Canada Limited (AECL) comprises a Hybrid Computer, consisting of two Applied Dynamic International AD/FIVE analog computers and a Digital Equipment Corporation (DEC) PDP-11/55 digital computer, and a Program Development System based on a DEC PDP-11/45 digital computer. This report describes the functions of the various hardware components of the Dynamic Analysis Facility and the interactions between them. A brief description of the software available to the user is also given. (auth)

Likelihood-based Dynamic Factor Analysis for Measurement and Forecasting

NARCIS (Netherlands)

Jungbacker, B.M.J.P.; Koopman, S.J.

2015-01-01

We present new results for the likelihood-based analysis of the dynamic factor model. The latent factors are modelled by linear dynamic stochastic processes. The idiosyncratic disturbance series are specified as autoregressive processes with mutually correlated innovations. The new results lead to

Dynamic Systems Analysis for Turbine Based Aero Propulsion Systems

Science.gov (United States)

Csank, Jeffrey T.

2016-01-01

The aircraft engine design process seeks to optimize the overall system-level performance, weight, and cost for a given concept. Steady-state simulations and data are used to identify trade-offs that should be balanced to optimize the system in a process known as systems analysis. These systems analysis simulations and data may not adequately capture the true performance trade-offs that exist during transient operation. Dynamic systems analysis provides the capability for assessing the dynamic tradeoffs at an earlier stage of the engine design process. The dynamic systems analysis concept, developed tools, and potential benefit are presented in this paper. To provide this capability, the Tool for Turbine Engine Closed-loop Transient Analysis (TTECTrA) was developed to provide the user with an estimate of the closed-loop performance (response time) and operability (high pressure compressor surge margin) for a given engine design and set of control design requirements. TTECTrA along with engine deterioration information, can be used to develop a more generic relationship between performance and operability that can impact the engine design constraints and potentially lead to a more efficient engine.

Practical method of dynamic analysis considering coupling effects between equipment and piping systems

International Nuclear Information System (INIS)

Koyanagi, Ryoichi

1984-01-01

Many piping systems are supported by flexible structures or attached to thin shell walls so it is very important to consider the dynamic coupling effects between these systems in dynamic analysis. This paper presents a practical method of dynamic analysis of an individual system considering the dynamic coupling effects of coupled equipment-piping systems. In this method, dynamic responses are calculated by using the modal information which is obtained from the other analysis for associative structure. Analytical results for the complete model and of this method for an individual system are presented in the piping-supporting structure system and a piping-shell system. From the comparison of these results, it shows that this method is accurate, useful and economically applicable to the dynamic analysis of large model. (author)

Dynamical renormalization group approach to transport in ultrarelativistic plasmas: The electrical conductivity in high temperature QED

International Nuclear Information System (INIS)

Boyanovsky, Daniel; Vega, Hector J. de; Wang Shangyung

2003-01-01

The dc electrical conductivity of an ultrarelativistic QED plasma is studied in real time by implementing the dynamical renormalization group. The conductivity is obtained from the real-time dependence of a dissipative kernel closely related to the retarded photon polarization. Pinch singularities in the imaginary part of the polarization are manifest as secular terms that grow in time in the perturbative expansion of this kernel. The leading secular terms are studied explicitly and it is shown that they are insensitive to the anomalous damping of hard fermions as a result of a cancellation between self-energy and vertex corrections. The resummation of the secular terms via the dynamical renormalization group leads directly to a renormalization group equation in real time, which is the Boltzmann equation for the (gauge invariant) fermion distribution function. A direct correspondence between the perturbative expansion and the linearized Boltzmann equation is established, allowing a direct identification of the self-energy and vertex contributions to the collision term. We obtain a Fokker-Planck equation in momentum space that describes the dynamics of the departure from equilibrium to leading logarithmic order in the coupling. This equation determines that the transport time scale is given by t tr =24 π/e 4 T ln(1/e). The solution of the Fokker-Planck equation approaches asymptotically the steady-state solution as ∼e -t/(4.038...t tr ) . The steady-state solution leads to the conductivity σ=15.698 T/e 2 ln(1/e) to leading logarithmic order. We discuss the contributions beyond leading logarithms as well as beyond the Boltzmann equation. The dynamical renormalization group provides a link between linear response in quantum field theory and kinetic theory

Computational social dynamic modeling of group recruitment.

Energy Technology Data Exchange (ETDEWEB)

Berry, Nina M.; Lee, Marinna; Pickett, Marc; Turnley, Jessica Glicken (Sandia National Laboratories, Albuquerque, NM); Smrcka, Julianne D. (Sandia National Laboratories, Albuquerque, NM); Ko, Teresa H.; Moy, Timothy David (Sandia National Laboratories, Albuquerque, NM); Wu, Benjamin C.

2004-01-01

The Seldon software toolkit combines concepts from agent-based modeling and social science to create a computationally social dynamic model for group recruitment. The underlying recruitment model is based on a unique three-level hybrid agent-based architecture that contains simple agents (level one), abstract agents (level two), and cognitive agents (level three). This uniqueness of this architecture begins with abstract agents that permit the model to include social concepts (gang) or institutional concepts (school) into a typical software simulation environment. The future addition of cognitive agents to the recruitment model will provide a unique entity that does not exist in any agent-based modeling toolkits to date. We use social networks to provide an integrated mesh within and between the different levels. This Java based toolkit is used to analyze different social concepts based on initialization input from the user. The input alters a set of parameters used to influence the values associated with the simple agents, abstract agents, and the interactions (simple agent-simple agent or simple agent-abstract agent) between these entities. The results of phase-1 Seldon toolkit provide insight into how certain social concepts apply to different scenario development for inner city gang recruitment.

Explorations in combining cognitive models of individuals and system dynamics models of groups.

Energy Technology Data Exchange (ETDEWEB)

Backus, George A.

2008-07-01

This report documents a demonstration model of interacting insurgent leadership, military leadership, government leadership, and societal dynamics under a variety of interventions. The primary focus of the work is the portrayal of a token societal model that responds to leadership activities. The model also includes a linkage between leadership and society that implicitly represents the leadership subordinates as they directly interact with the population. The societal model is meant to demonstrate the efficacy and viability of using System Dynamics (SD) methods to simulate populations and that these can then connect to cognitive models depicting individuals. SD models typically focus on average behavior and thus have limited applicability to describe small groups or individuals. On the other hand, cognitive models readily describe individual behavior but can become cumbersome when used to describe populations. Realistic security situations are invariably a mix of individual and population dynamics. Therefore, the ability to tie SD models to cognitive models provides a critical capability that would be otherwise be unavailable.

Nonlinear Dynamical Analysis for a Plain Bearing

Directory of Open Access Journals (Sweden)

Ali Belhamra

2014-03-01

Full Text Available This paper investigates the nonlinear dynamic behavior for a plain classic bearing (fluid bearing lubricated by a non-Newtonian fluid of a turbo machine rotating with high speed; this type of fluid contains additives viscosity (couple-stress fluid film. The solution of the nonlinear dynamic problem of this type of bearing is determined with a spatial discretisation of the modified Reynolds' equation written in dynamic mode by using the optimized short bearing theory and a temporal discretisation for equations of rotor motion by the help of Euler's explicit diagram. This study analyzes the dynamic behavior of a rotor supported by two couple-stress fluid film journal lubricant enhances the dynamic stability of the rotor-bearing system considerably compared to that obtained when using a traditional Newtonian lubricant. The analysis shows that the dynamic behavior of a shaft which turns with high velocities is strongly nonlinear even for poor eccentricities of unbalance; the presence of parameters of couple stress allows strongly attenuating the will synchrony (unbalance and asynchrony (whipping amplitudes of vibrations of the shaft which supports more severe conditions (large unbalances.

Towards automatic analysis of dynamic radionuclide studies using principal-components factor analysis

International Nuclear Information System (INIS)

Nigran, K.S.; Barber, D.C.

1985-01-01

A method is proposed for automatic analysis of dynamic radionuclide studies using the mathematical technique of principal-components factor analysis. This method is considered as a possible alternative to the conventional manual regions-of-interest method widely used. The method emphasises the importance of introducing a priori information into the analysis about the physiology of at least one of the functional structures in a study. Information is added by using suitable mathematical models to describe the underlying physiological processes. A single physiological factor is extracted representing the particular dynamic structure of interest. Two spaces 'study space, S' and 'theory space, T' are defined in the formation of the concept of intersection of spaces. A one-dimensional intersection space is computed. An example from a dynamic 99 Tcsup(m) DTPA kidney study is used to demonstrate the principle inherent in the method proposed. The method requires no correction for the blood background activity, necessary when processing by the manual method. The careful isolation of the kidney by means of region of interest is not required. The method is therefore less prone to operator influence and can be automated. (author)

Off-road vehicle dynamics analysis, modelling and optimization

CERN Document Server

Taghavifar, Hamid

2017-01-01

This book deals with the analysis of off-road vehicle dynamics from kinetics and kinematics perspectives and the performance of vehicle traversing over rough and irregular terrain. The authors consider the wheel performance, soil-tire interactions and their interface, tractive performance of the vehicle, ride comfort, stability over maneuvering, transient and steady state conditions of the vehicle traversing, modeling the aforementioned aspects and optimization from energetic and vehicle mobility perspectives. This book brings novel figures for the transient dynamics and original wheel terrain dynamics at on-the-go condition.

Membership status and subjective group dynamics: who triggers the black sheep effect?

Science.gov (United States)

Pinto, Isabel R; Marques, José M; Levine, John M; Abrams, Dominic

2010-07-01

In 3 experiments, participants (Ns = 50, 95, and 75, respectively) judged 2 ingroup or outgroup members who occupied 1 of 3 statuses--new members, full members, or marginal members. In each case, 1 of these members adopted a normative position and another supported a deviant position regarding a relevant issue. Participants upgraded normative ingroup full members and derogated deviant ingroup full members compared with all other members. In addition, derogation of deviant ingroup members was associated with a socializing and a punishing intention toward new members and full members, respectively. These results are discussed in terms of the group socialization model (e.g., Levine & Moreland, 1994) and the subjective group dynamics model (e.g., Marques, Paez, & Abrams, 1998).

String Analysis for Dynamic Field Access

DEFF Research Database (Denmark)

Madsen, Magnus; Andreasen, Esben

2014-01-01

domains to reason about dynamic field access in a static analysis tool. A key feature of the domains is that the equal, concatenate and join operations take Ο(1) time. Experimental evaluation on four common JavaScript libraries, including jQuery and Prototype, shows that traditional string domains...

Group analysis and renormgroup symmetries

International Nuclear Information System (INIS)

Kovalev, V.F.; Pustovalov, V.V.; Shirkov, D.V.

1996-01-01

An original regular approach to constructing special type symmetries for boundary-value problems, namely renormgroup symmetries, is presented. Different methods of calculating these symmetries based on modern group analysis are described. An application of the approach to boundary value problems is demonstrated with the help of a simple mathematical model. 35 refs

Structural dynamic analysis of turbine blade

Science.gov (United States)

Antony, A. Daniel; Gopalsamy, M.; Viswanadh, Chaparala B. V.; Krishnaraj, R.

2017-10-01

In any gas turbine design cycle, blade design is a crucial element which needs maximum attention to meet the aerodynamic performance, structural safety margins, manufacturing feasibility, material availability etc. In present day gas turbine engines, most of the failures occur during engine development test and in-service, in rotor and stator blades due to fatigue and resonance failures. To address this issue, an extensive structural dynamic analysis is carried out to predict the natural frequencies and mode shapes using FE methods. Using the dynamics characteristics, the Campbell diagram is constructed to study the possibility of resonance at various operating speeds. In this work, the feasibility of using composite material in place of titanium alloy from the structural dynamics point of view. This is being attempted in a Low-pressure compressor where the temperatures are relatively low and fixed with the casings. The analysis will be carried out using FE method for different composite material with different lamina orientations chosen through the survey. This study will focus on the sensitivity of blade mode shapes to different laminae orientations, which will be used to alter the natural frequency and tailor the mode shapes. Campbell diagrams of existing titanium alloy are compared with the composite materials with different laminae at all critical operating conditions. The existing manufacturing methods and the proven techniques for blade profiles will also be discussed in this report.

S-Lagrangian dynamics of many-body systems and behavior of social groups: Dominance and hierarchy formation

Science.gov (United States)

Sandler, U.

2017-11-01

In this paper, we extend our generalized Lagrangian dynamics (i.e., S-Lagrangian dynamics, which can be applied equally to physical and non-physical systems as per Sandler (2014)) to many-body systems. Unlike common Lagrangian dynamics, this is not a trivial task. For many-body systems with S-dependent Lagrangians, the Lagrangian and the corresponding Hamiltonian or energy become vector functions, conjugated momenta become second-order tensors, and the system inevitably develops a hierarchical structure, even if all bodies initially have similar status and Lagrangians. As an application of our theory, we consider dominance and hierarchy formation, which is present in almost all communities of living species. As a biological basis for this application, we assume that the primary motivation of a groups activity is to attempt to cope with stress arising as pressure from the environment and from intrinsic unmet needs of individuals. It has been shown that the S-Lagrangian approach to a group's evolution naturally leads to formation of linear or despotic dominance hierarchies, depending on differences between individuals in coping with stress. That is, individuals that cope more readily with stress take leadership roles during the evolution. Experimental results in animal groups which support our assumption and findings are considered.

Assessment of stability during gait in patients with spinal deformity-A preliminary analysis using the dynamic stability margin.

Science.gov (United States)

Simon, Anne-Laure; Lugade, Vipul; Bernhardt, Kathie; Larson, A Noelle; Kaufman, Kenton

2017-06-01

Daily living activities are dynamic, requiring spinal motion through space. Current assessment of spinal deformities is based on static measurements from full-spine standing radiographs. Tools to assess dynamic stability during gait might be useful to enhance the standard evaluation. The aim of this study was to evaluate gait dynamic imbalance in patients with spinal deformity using the dynamic stability margin (DSM). Twelve normal subjects and 17 patients with spinal deformity were prospectively recruited. A kinematic 3D gait analysis was performed for the control group (CG) and the spinal deformity group (SDG). The DSM (distance between the extrapolated center of mass and the base of support) and time-distance parameters were calculated for the right and left side during gait. The relationship between DSM and step length was assessed using three variables: gait stability, symmetry, and consistency. Variables' accuracy was validated by a discriminant analysis. Patients with spinal deformity exhibited gait instability according to the DSM (0.25m versus 0.31m) with decreased velocity (1.1ms -1 versus 1.3ms -1 ) and decreased step length (0.32m versus 0.38m). According to the discriminant analysis, gait stability was the more accurate variable (area under the curve AUC=0.98) followed by gait symmetry and consistency. However, gait consistency showed 100% of specificity, sensitivity, and accuracy of precision. The DSM showed that patients with spinal malalignment exhibit decreased gait stability, symmetry, and consistency besides gait time-distance parameter changes. Additional work is required to determine how to apply the DSM for preoperative and postoperative spinal deformity management. Copyright © 2017. Published by Elsevier B.V.

Operationalizing sustainability in urban coastal systems: a system dynamics analysis.

Science.gov (United States)

Mavrommati, Georgia; Bithas, Kostas; Panayiotidis, Panayiotis

2013-12-15

We propose a system dynamics approach for Ecologically Sustainable Development (ESD) in urban coastal systems. A systematic analysis based on theoretical considerations, policy analysis and experts' knowledge is followed in order to define the concept of ESD. The principles underlying ESD feed the development of a System Dynamics Model (SDM) that connects the pollutant loads produced by urban systems' socioeconomic activities with the ecological condition of the coastal ecosystem that it is delineated in operational terms through key biological elements defined by the EU Water Framework Directive. The receiving waters of the Athens Metropolitan area, which bears the elements of typical high population density Mediterranean coastal city but which currently has also new dynamics induced by the ongoing financial crisis, are used as an experimental system for testing a system dynamics approach to apply the concept of ESD. Systems' thinking is employed to represent the complex relationships among the components of the system. Interconnections and dependencies that determine the potentials for achieving ESD are revealed. The proposed system dynamics analysis can facilitate decision makers to define paths of development that comply with the principles of ESD. Copyright © 2013 Elsevier Ltd. All rights reserved.

Dynamic analysis and design of offshore structures

CERN Document Server

Chandrasekaran, Srinivasan

2015-01-01

This book  attempts to provide readers with an overall idea of various types of offshore platform geometries. It covers the various environmental loads encountered by these structures, a detailed description of the fundamentals of structural dynamics in a class-room style, estimate of damping in offshore structures and their applications in the preliminary analysis and design. Basic concepts of structural dynamics are emphasized through simple illustrative examples and exercises. Design methodologies and guidelines, which are FORM based concepts are explained through a few applied example structures. Each chapter also has tutorials and exercises for self-learning. A dedicated chapter on stochastic dynamics will help the students to extend the basic concepts of structural dynamics to this advanced domain of research. Hydrodynamic response of offshore structures with perforated members is one of the recent research applications, which is found to be one of the effective manner of retrofitting offshore structur...

Discrete time and continuous time dynamic mean-variance analysis

OpenAIRE

Reiss, Ariane

1999-01-01

Contrary to static mean-variance analysis, very few papers have dealt with dynamic mean-variance analysis. Here, the mean-variance efficient self-financing portfolio strategy is derived for n risky assets in discrete and continuous time. In the discrete setting, the resulting portfolio is mean-variance efficient in a dynamic sense. It is shown that the optimal strategy for n risky assets may be dominated if the expected terminal wealth is constrained to exactly attain a certain goal instead o...

Discretization model for nonlinear dynamic analysis of three dimensional structures

International Nuclear Information System (INIS)

Hayashi, Y.

1982-12-01

A discretization model for nonlinear dynamic analysis of three dimensional structures is presented. The discretization is achieved through a three dimensional spring-mass system and the dynamic response obtained by direct integration of the equations of motion using central diferences. First the viability of the model is verified through the analysis of homogeneous linear structures and then its performance in the analysis of structures subjected to impulsive or impact loads, taking into account both geometrical and physical nonlinearities is evaluated. (Author) [pt

Dynamical symmetry breaking of the electroweak interactions and the renormalization group

International Nuclear Information System (INIS)

Hill, C.T.

1990-08-01

We discuss dynamical symmetry breaking with an emphasis on the renormalization group as the key tool to obtaining reliable predictions. In particular we discuss the mechanism for breaking the electroweak interactions which relies upon the formation of condensates involving the conventional quarks and leptons. Such a scheme indicates that the top quark is heavy, greater than or of order 200 GeV, and gives further predictions for the Higgs boson mass. We also briefly describe recent attempts to incorporate a 4th generation in a more natural scheme. 13 refs., 3 figs., 1 tab

Quantum groups, orthogonal polynomials and applications to some dynamical systems; Groupes quantiques, polynomes orthogonaux et applications a quelques systemes dynamiques

Energy Technology Data Exchange (ETDEWEB)

Campigotto, C

1993-12-01

The first part is concerned with the introduction of quantum groups as an extension of Lie groups. In particular, we study the case of unitary enveloping algebras in dimension 2. We then connect the quantum group formalism to the construction of g CGC recurrent relations. In addition, we construct g-deformed Krawtchouck and Meixner orthogonal polynomials and list their respective main characteristics. The second part deals with some dynamical systems from a classical, a quantum and a gp-analogue point of view. We investigate the Coulomb Kepler system by using the canonical namical systems which contain as special cases some interesting systems for nuclear of atomic physics and for quantum chemistry, such as the Hartmann system, the ring-shaped oscillator, the Smarodinsky-Winternitz system, the Aharonov-Bohen system and the dyania of Dirac and Schroedinger. (author). 291 refs.

RADYBAN: A tool for reliability analysis of dynamic fault trees through conversion into dynamic Bayesian networks

International Nuclear Information System (INIS)

Montani, S.; Portinale, L.; Bobbio, A.; Codetta-Raiteri, D.

2008-01-01

In this paper, we present RADYBAN (Reliability Analysis with DYnamic BAyesian Networks), a software tool which allows to analyze a dynamic fault tree relying on its conversion into a dynamic Bayesian network. The tool implements a modular algorithm for automatically translating a dynamic fault tree into the corresponding dynamic Bayesian network and exploits classical algorithms for the inference on dynamic Bayesian networks, in order to compute reliability measures. After having described the basic features of the tool, we show how it operates on a real world example and we compare the unreliability results it generates with those returned by other methodologies, in order to verify the correctness and the consistency of the results obtained

Dynamic stiffness and seismic input motion of a group of battered piles

International Nuclear Information System (INIS)

Wolf, J.P.

1979-01-01

The dynamic stiffness (impedance function) and the corresponding seismic input motion of a group of battered piles, which can be end-bearing and floating, situated in any desired configuration in horizontally stratified soil, are determined. The soil and the piles consist of (frequency-dependent) visco-elastic material with hysteretic damping. The base mat can be rigid or flexible. Any seismic excitation, for which the free-field motion can be calculated, can be specified (body waves, propagating at an arbitrary angle, generalized surface waves). The soil is discretized by toroidal finite elements in conjunction with a Fourier expansion in the circumferential direction. Radiation and hysteretic damping are accounted for. The dynamic-flexibility matrix of the soil is generated, superimposing the basic dynamic-flexibility coefficients calculated by applying sequentially a horizontal and a vertical force at all nodes located on the axis of symmetry. The influence of the soil which is subsequently replaced by piles is taken into consideration. Pile-soil-pile interaction is accounted for in this method. The formulation can also be applied to embedded foundation and buried structures such as tunnels and pipe systems. (Auth.)

Dynamics of bone healing after osteotomy with piezosurgery or conventional drilling – histomorphometrical, immunohistochemical, and molecular analysis

Science.gov (United States)

2013-01-01

Background Piezosurgery is an osteotomy system used in medical and dental surgery. Many studies have proven clinical advantages of piezosurgery in terms of quality of cut, maneuverability, ease of use, and safety. However, few investigations have tested its superiority over the traditional osteotomy systems in terms of dynamics of bone healing. Therefore, the aim of this study was to evaluate the dynamics of bone healing after osteotomies with piezosurgery and to compare them with those associated to traditional bone drilling. Methods One hundred and ten rats were divided into two groups with 55 animals each. The animals were anesthetized and the tibiae were surgically exposed to create defects 2 mm in diameter by using piezosurgery (Piezo group) and conventional drilling (Drill group). Animals were sacrificed at 3, 7, 14, 30 and 60 days post-surgery. Bone samples were collected and processed for histological, histomorphometrical, immunohistochemical, and molecular analysis. The histological analysis was performed at all time points (n = 8) whereas the histomorphometrical analysis was performed at 7, 14, 30 and 60 days post-surgery (n = 8). The immunolabeling was performed to detect Vascular Endothelial Growth Factor (VEGF), Caspase-3 (CAS-3), Osteoprotegerin (OPG), Receptor Activator of Nuclear Factor kappa-B Ligand (RANKL), and Osteocalcin (OC) at 3, 7, and 14 days (n = 3). For the molecular analysis, animals were sacrificed at 3, 7 and 14 days, total RNA was collected, and quantification of the expression of 21 genes related to BMP signaling, Wnt signaling, inflammation, osteogenenic and apoptotic pathways was performed by qRT-PCR (n = 5). Results Histologically and histomorphometrically, bone healing was similar in both groups with the exception of a slightly higher amount of newly formed bone observed at 30 days after piezosurgery (p piezosurgery are comparable to those observed with conventional drilling. PMID:24053147

A Rigorous, Compositional, and Extensible Framework for Dynamic Fault Tree Analysis

NARCIS (Netherlands)

Boudali, H.; Sandhu, R.; Crouzen, Pepijn; Stoelinga, Mariëlle Ida Antoinette

Fault trees (FT) are among the most prominent formalisms for reliability analysis of technical systems. Dynamic FTs extend FTs with support for expressing dynamic dependencies among components. The standard analysis vehicle for DFTs is state-based, and treats the model as a CTMC, a continuous-time

Dynamic response analysis of the PSE torus

International Nuclear Information System (INIS)

Arthur, D.F.

1977-01-01

The paper describes a structural dynamic analysis of the 1 / 5 -scale BWR toroidal wetwell. The subscale toroidal wetwell is part of the Pressure Suppression Experiment Facility at Lawrence Livermore Laboratory. The analysis objective is to show that experimental structural loads measured by load cells in the wetwell supports are consistent with the internal hydrodynamic forcing function measured by pressure transducers. Finite element analysis of the wetwell indicates that the load and pressure measurements are consistent

Theory and analysis of nonlinear dynamics and stability in storage rings: A working group summary

International Nuclear Information System (INIS)

Chattopadhyay, S.; Audy, P.; Courant, E.D.

1988-07-01

A summary and commentary of the available theoretical and analytical tools and recent advances in the nonlinear dynamics, stability and aperture issues in storage rings are presented. 11 refs., 4 figs

Dynamical analysis for a vector-like dark energy

Energy Technology Data Exchange (ETDEWEB)

Landim, Ricardo C.G. [Instituto de Fisica, Universidade de Sao Paulo, Departamento de Fisica-Matematica, Sao Paulo, SP (Brazil)

2016-09-15

In this paper we perform a dynamical analysis for a vector field as a candidate for the dark energy, in the presence of a barotropic fluid. The vector is one component of the so-called cosmic triad, which is a set of three identical copies of an abelian field pointing mutually in orthogonal directions. In order to generalize the analysis, we also assumed the interaction between dark energy and the barotropic fluid, with a phenomenological coupling. Both matter and dark energy eras can be successfully described by the critical points, indicating that the dynamical system theory is a viable tool to analyze asymptotic states of such cosmological models. (orig.)

Statics and dynamics of free and hydrogen-bonded OH groups at the air/water interface.

Science.gov (United States)

Vila Verde, Ana; Bolhuis, Peter G; Campen, R Kramer

2012-08-09

We use classical atomistic molecular dynamics simulations of two water models (SPC/E and TIP4P/2005) to investigate the orientation and reorientation dynamics of two subpopulations of OH groups belonging to water molecules at the air/water interface at 300 K: those OH groups that donate a hydrogen bond (called "bonded") and those that do not (called "free"). Free interfacial OH groups reorient in two distinct regimes: a fast regime from 0 to 1 ps and a slow regime thereafter. Qualitatively similar behavior was reported by others for free OH groups near extended hydrophobic surfaces. In contrast, the net reorientation of bonded OH groups occurs at a rate similar to that of bulk water. This similarity in reorientation rate results from compensation of two effects: decreasing frequency of hydrogen-bond breaking/formation (i.e., hydrogen-bond exchange) and faster rotation of intact hydrogen bonds. Both changes result from the decrease in density at the air/water interface relative to the bulk. Interestingly, because of the presence of capillary waves, the slowdown of hydrogen-bond exchange is significantly smaller than that reported for water near extended hydrophobic surfaces, but it is almost identical to that reported for water near small hydrophobic solutes. In this sense water at the air/water interface has characteristics of water of hydration of both small and extended hydrophobic solutes.

Group-sequential analysis may allow for early trial termination

DEFF Research Database (Denmark)

Gerke, Oke; Vilstrup, Mie H; Halekoh, Ulrich

2017-01-01

BACKGROUND: Group-sequential testing is widely used in pivotal therapeutic, but rarely in diagnostic research, although it may save studies, time, and costs. The purpose of this paper was to demonstrate a group-sequential analysis strategy in an intra-observer study on quantitative FDG-PET/CT mea......BACKGROUND: Group-sequential testing is widely used in pivotal therapeutic, but rarely in diagnostic research, although it may save studies, time, and costs. The purpose of this paper was to demonstrate a group-sequential analysis strategy in an intra-observer study on quantitative FDG...... assumed to be normally distributed, and sequential one-sided hypothesis tests on the population standard deviation of the differences against a hypothesised value of 1.5 were performed, employing an alpha spending function. The fixed-sample analysis (N = 45) was compared with the group-sequential analysis...... strategies comprising one (at N = 23), two (at N = 15, 30), or three interim analyses (at N = 11, 23, 34), respectively, which were defined post hoc. RESULTS: When performing interim analyses with one third and two thirds of patients, sufficient agreement could be concluded after the first interim analysis...

'Optimal conditions for group-dynamic challenges' : The results of mock-up research on group-dynamics during the January 2014 Juuka Finland ‘Ice Dome’ building by university students initiated by the Eindhoven Technical University

NARCIS (Netherlands)

Sanders, F.C.; Overtoom, M.E.

2016-01-01

Society counts a growing number of group-dynamic challenges like civilian movements, resident initia-tive, self steering teams on the work floor and innovation team challenges. The basis driving force is governments that draw back, increasing competition in business and empowerment of people.

Testing all six person-oriented principles in dynamic factor analysis.

Science.gov (United States)

Molenaar, Peter C M

2010-05-01

All six person-oriented principles identified by Sterba and Bauer's Keynote Article can be tested by means of dynamic factor analysis in its current form. In particular, it is shown how complex interactions and interindividual differences/intraindividual change can be tested in this way. In addition, the necessity to use single-subject methods in the analysis of developmental processes is emphasized, and attention is drawn to the possibility to optimally treat developmental psychopathology by means of new computational techniques that can be integrated with dynamic factor analysis.

Comparing dynamical systems concepts and techniques for biomechanical analysis

Institute of Scientific and Technical Information of China (English)

Richard E.A. van Emmerik; Scott W. Ducharme; Avelino C. Amado; Joseph Hamill

2016-01-01

Traditional biomechanical analyses of human movement are generally derived from linear mathematics. While these methods can be useful in many situations, they do not describe behaviors in human systems that are predominately nonlinear. For this reason, nonlinear analysis methods based on a dynamical systems approach have become more prevalent in recent literature. These analysis techniques have provided new insights into how systems (1) maintain pattern stability, (2) transition into new states, and (3) are governed by short-and long-term (fractal) correlational processes at different spatio-temporal scales. These different aspects of system dynamics are typically investigated using concepts related to variability, stability, complexity, and adaptability. The purpose of this paper is to compare and contrast these different concepts and demonstrate that, although related, these terms represent fundamentally different aspects of system dynamics. In particular, we argue that variability should not uniformly be equated with stability or complexity of movement. In addition, current dynamic stability measures based on nonlinear analysis methods (such as the finite maximal Lyapunov exponent) can reveal local instabilities in movement dynamics, but the degree to which these local instabilities relate to global postural and gait stability and the ability to resist external perturbations remains to be explored. Finally, systematic studies are needed to relate observed reductions in complexity with aging and disease to the adaptive capabilities of the movement system and how complexity changes as a function of different task constraints.

Comparing dynamical systems concepts and techniques for biomechanical analysis

Directory of Open Access Journals (Sweden)

Richard E.A. van Emmerik

2016-03-01

Full Text Available Traditional biomechanical analyses of human movement are generally derived from linear mathematics. While these methods can be useful in many situations, they do not describe behaviors in human systems that are predominately nonlinear. For this reason, nonlinear analysis methods based on a dynamical systems approach have become more prevalent in recent literature. These analysis techniques have provided new insights into how systems (1 maintain pattern stability, (2 transition into new states, and (3 are governed by short- and long-term (fractal correlational processes at different spatio-temporal scales. These different aspects of system dynamics are typically investigated using concepts related to variability, stability, complexity, and adaptability. The purpose of this paper is to compare and contrast these different concepts and demonstrate that, although related, these terms represent fundamentally different aspects of system dynamics. In particular, we argue that variability should not uniformly be equated with stability or complexity of movement. In addition, current dynamic stability measures based on nonlinear analysis methods (such as the finite maximal Lyapunov exponent can reveal local instabilities in movement dynamics, but the degree to which these local instabilities relate to global postural and gait stability and the ability to resist external perturbations remains to be explored. Finally, systematic studies are needed to relate observed reductions in complexity with aging and disease to the adaptive capabilities of the movement system and how complexity changes as a function of different task constraints.

Perturbation analysis for patch occupancy dynamics

Science.gov (United States)

Martin, Julien; Nichols, James D.; McIntyre, Carol L.; Ferraz, Goncalo; Hines, James E.

2009-01-01

Perturbation analysis is a powerful tool to study population and community dynamics. This article describes expressions for sensitivity metrics reflecting changes in equilibrium occupancy resulting from small changes in the vital rates of patch occupancy dynamics (i.e., probabilities of local patch colonization and extinction). We illustrate our approach with a case study of occupancy dynamics of Golden Eagle (Aquila chrysaetos) nesting territories. Examination of the hypothesis of system equilibrium suggests that the system satisfies equilibrium conditions. Estimates of vital rates obtained using patch occupancy models are used to estimate equilibrium patch occupancy of eagles. We then compute estimates of sensitivity metrics and discuss their implications for eagle population ecology and management. Finally, we discuss the intuition underlying our sensitivity metrics and then provide examples of ecological questions that can be addressed using perturbation analyses. For instance, the sensitivity metrics lead to predictions about the relative importance of local colonization and local extinction probabilities in influencing equilibrium occupancy for rare and common species.

Group-theoretical and topological analysis of localized rotation-vibration states

International Nuclear Information System (INIS)

Sadovskii, D.A.; Zhilinskii, B.I.

1993-01-01

A general scheme of qualitative analysis is applied to molecular rovibrational problems. The classical-quantum correspondence provides a description of different classes of localized quantum rotation-vibration states associated with localized classical motion. A description of qualitative features, such as localized motion, and of qualitative changes, such as localization phenomena, is based on the concept of the simplest Hamiltonian. It uses only the topological properties of the compact reduced phase space and the action of the symmetry group on this space. The qualitative changes of the simplest Hamiltonian are analyzed as bifurcations caused by rotational or vibrational excitation. The relation between the stationary points of the classical Hamiltonian function on the reduced phase space and the principal periodic trajectories in the coordinate space is analyzed for vibrational Hamiltonians. In particular, the relation between the nonlinear normal modes, proposed by Montaldi, Roberts, and Stewart [Philos. Trans. R. Soc. London, Ser. A 325, 237 (1988)], and normal- and local-mode models widely used in molecular physics is discussed. Along with a general consideration of localized rotational and vibrational states a more detailed analysis of the vibrational dynamics of an X 3 molecule with the D 3h symmetry, such as the H 3 + molecular ion, is given

Dynamic modeling and dynamical analysis of pump-turbines in S-shaped regions during runaway operation

International Nuclear Information System (INIS)

Zhang, Hao; Chen, Diyi; Wu, Changzhi; Wang, Xiangyu; Lee, Jae-Myung; Jung, Kwang-Hyo

2017-01-01

Highlights: • Novel dynamic model of a pump-turbine in S-shaped regions is proposed. • A stability criterion of runaway point is given. • Global dynamic characteristics of the pump-turbine are investigated. • Effects of the slopes of the characteristic curve on the stability are studied. - Abstract: There is a region of pump-turbine operation, often called the S-shaped region, in which one unit rotational speed corresponds to three unit flows or torques. In this paper, the dynamic model of the pump-turbine in S-shaped regions is established by introducing the nonlinear piecewise function of relative parameters. Then, the global bifurcation diagrams of the pump-turbine are presented to analyze its dynamic characteristics in the S-shaped regions. Meanwhile, a stability criterion of runaway point is given based on the established theoretical model. The numerical experiments are conducted on the model and the results are in good agreement with the theoretical analysis. Furthermore, the effects of the characteristic curve slopes on the stability of the pump-turbine are studied by an innovative use of the three-dimensional bifurcation diagrams. Finally, the factors influencing the runaway stability of pump-turbines are also discussed, based on the dynamic analysis.

Analysis Of Dynamic Dent Resistance Of Auto Body Panel

International Nuclear Information System (INIS)

Deolgaonkar, S. S.; Nandedkar, V. M.

2007-01-01

In automotive industry there is increasing demand for higher quality exterior panels, better functional properties and lower weight. The demand for weight reduction has led to thinner sheets, greater use of high strength steels and a change from steel to aluminum grades. This thickness reduction, which causes decrease in the dent resistance, promoted examination of the dent resistance against static and dynamic concentrated loads. This paper describes an investigation of the suitability of explicit dynamic FE analysis as a mean to determine the dynamic dent properties of the panel. This investigation is carried out on the body panel of utility vehicle and covers two parts, in first experimental analysis is carried out on developed test rig, which is interfaced with the computer. This test rig measures deflection with accuracy of .001mm. The experimental results are then compared with the simulation results, which is the second part. Simulation is carried with non-linear transient dynamic explicit analysis using Ansys -Ls Dyna. The experimental results show great accuracy with simulation results. The effect of change in thickness and geometry of the existing fender is then studied with help of simulation technique. By considering the best possible option overall weight of fender is reduced by 7.07 % by keeping the dent resistance of the panel constant

Computer Programme for the Dynamic Analysis of Tall Regular ...

African Journals Online (AJOL)

The traditional method of dynamic analysis of tall rigid frames assumes the shear frame model. Models that allow joint rotations with/without the inclusion of the column axial loads give improved results but pose much more computational difficulty. In this work a computer program Natfrequency that determines the dynamic ...

Impact parameter analysis and soft QCD dynamics

International Nuclear Information System (INIS)

Carvalho, P.A.S.; Martini, A.F.; Menon, M.J.

2002-01-01

In a recent paper, based on the hypothesis of light-cone dipole representation for gluon Bremsstrahlung, Kopeliovich et al. developed a dynamical model for the elastic hadronic amplitude. The model has been applied to pp and p (bar) p scattering and the effects of unitarity and peripheral interactions have been investigated in the impact parameter representation. In this communication, making use of a model independent extraction of the scattering amplitude in the impact parameter space (early developed), we represent a comparative study between the predictions from the dynamical model and the impact parameter analysis. (author)

Extracting neuronal functional network dynamics via adaptive Granger causality analysis.

Science.gov (United States)

Sheikhattar, Alireza; Miran, Sina; Liu, Ji; Fritz, Jonathan B; Shamma, Shihab A; Kanold, Patrick O; Babadi, Behtash

2018-04-24

Quantifying the functional relations between the nodes in a network based on local observations is a key challenge in studying complex systems. Most existing time series analysis techniques for this purpose provide static estimates of the network properties, pertain to stationary Gaussian data, or do not take into account the ubiquitous sparsity in the underlying functional networks. When applied to spike recordings from neuronal ensembles undergoing rapid task-dependent dynamics, they thus hinder a precise statistical characterization of the dynamic neuronal functional networks underlying adaptive behavior. We develop a dynamic estimation and inference paradigm for extracting functional neuronal network dynamics in the sense of Granger, by integrating techniques from adaptive filtering, compressed sensing, point process theory, and high-dimensional statistics. We demonstrate the utility of our proposed paradigm through theoretical analysis, algorithm development, and application to synthetic and real data. Application of our techniques to two-photon Ca 2+ imaging experiments from the mouse auditory cortex reveals unique features of the functional neuronal network structures underlying spontaneous activity at unprecedented spatiotemporal resolution. Our analysis of simultaneous recordings from the ferret auditory and prefrontal cortical areas suggests evidence for the role of rapid top-down and bottom-up functional dynamics across these areas involved in robust attentive behavior.

Nonlinear dynamic mechanism of vocal tremor from voice analysis and model simulations

Science.gov (United States)

Zhang, Yu; Jiang, Jack J.

2008-09-01

Nonlinear dynamic analysis and model simulations are used to study the nonlinear dynamic characteristics of vocal folds with vocal tremor, which can typically be characterized by low-frequency modulation and aperiodicity. Tremor voices from patients with disorders such as paresis, Parkinson's disease, hyperfunction, and adductor spasmodic dysphonia show low-dimensional characteristics, differing from random noise. Correlation dimension analysis statistically distinguishes tremor voices from normal voices. Furthermore, a nonlinear tremor model is proposed to study the vibrations of the vocal folds with vocal tremor. Fractal dimensions and positive Lyapunov exponents demonstrate the evidence of chaos in the tremor model, where amplitude and frequency play important roles in governing vocal fold dynamics. Nonlinear dynamic voice analysis and vocal fold modeling may provide a useful set of tools for understanding the dynamic mechanism of vocal tremor in patients with laryngeal diseases.

Ignalina Safety Analysis Group's report for the year 1998

International Nuclear Information System (INIS)

Uspuras, E.; Augutis, J.; Bubelis, E.; Cesna, B.; Kaliatka, A.

1999-02-01

Results of Ignalina NPP Safety Analysis Group's research are presented. The main fields of group's activities in 1998 were following: safety analysis of reactor's cooling system, safety analysis of accident localization system, investigation of the problem graphite - fuel channel, reactor core modelling, assistance to the regulatory body VATESI in drafting regulations and reviewing safety reports presented by Ignalina NPP during the process of licensing of unit 1

Conformational and functional analysis of molecular dynamics trajectories by Self-Organising Maps

Directory of Open Access Journals (Sweden)

Stella Fabio

2011-05-01

Full Text Available Abstract Background Molecular dynamics (MD simulations are powerful tools to investigate the conformational dynamics of proteins that is often a critical element of their function. Identification of functionally relevant conformations is generally done clustering the large ensemble of structures that are generated. Recently, Self-Organising Maps (SOMs were reported performing more accurately and providing more consistent results than traditional clustering algorithms in various data mining problems. We present a novel strategy to analyse and compare conformational ensembles of protein domains using a two-level approach that combines SOMs and hierarchical clustering. Results The conformational dynamics of the α-spectrin SH3 protein domain and six single mutants were analysed by MD simulations. The Cα's Cartesian coordinates of conformations sampled in the essential space were used as input data vectors for SOM training, then complete linkage clustering was performed on the SOM prototype vectors. A specific protocol to optimize a SOM for structural ensembles was proposed: the optimal SOM was selected by means of a Taguchi experimental design plan applied to different data sets, and the optimal sampling rate of the MD trajectory was selected. The proposed two-level approach was applied to single trajectories of the SH3 domain independently as well as to groups of them at the same time. The results demonstrated the potential of this approach in the analysis of large ensembles of molecular structures: the possibility of producing a topological mapping of the conformational space in a simple 2D visualisation, as well as of effectively highlighting differences in the conformational dynamics directly related to biological functions. Conclusions The use of a two-level approach combining SOMs and hierarchical clustering for conformational analysis of structural ensembles of proteins was proposed. It can easily be extended to other study cases and to

Conformational and functional analysis of molecular dynamics trajectories by Self-Organising Maps

Science.gov (United States)

2011-01-01

Background Molecular dynamics (MD) simulations are powerful tools to investigate the conformational dynamics of proteins that is often a critical element of their function. Identification of functionally relevant conformations is generally done clustering the large ensemble of structures that are generated. Recently, Self-Organising Maps (SOMs) were reported performing more accurately and providing more consistent results than traditional clustering algorithms in various data mining problems. We present a novel strategy to analyse and compare conformational ensembles of protein domains using a two-level approach that combines SOMs and hierarchical clustering. Results The conformational dynamics of the α-spectrin SH3 protein domain and six single mutants were analysed by MD simulations. The Cα's Cartesian coordinates of conformations sampled in the essential space were used as input data vectors for SOM training, then complete linkage clustering was performed on the SOM prototype vectors. A specific protocol to optimize a SOM for structural ensembles was proposed: the optimal SOM was selected by means of a Taguchi experimental design plan applied to different data sets, and the optimal sampling rate of the MD trajectory was selected. The proposed two-level approach was applied to single trajectories of the SH3 domain independently as well as to groups of them at the same time. The results demonstrated the potential of this approach in the analysis of large ensembles of molecular structures: the possibility of producing a topological mapping of the conformational space in a simple 2D visualisation, as well as of effectively highlighting differences in the conformational dynamics directly related to biological functions. Conclusions The use of a two-level approach combining SOMs and hierarchical clustering for conformational analysis of structural ensembles of proteins was proposed. It can easily be extended to other study cases and to conformational ensembles from

Group-sequential analysis may allow for early trial termination

DEFF Research Database (Denmark)

Gerke, Oke; Vilstrup, Mie H; Halekoh, Ulrich

2017-01-01

BACKGROUND: Group-sequential testing is widely used in pivotal therapeutic, but rarely in diagnostic research, although it may save studies, time, and costs. The purpose of this paper was to demonstrate a group-sequential analysis strategy in an intra-observer study on quantitative FDG-PET/CT mea......BACKGROUND: Group-sequential testing is widely used in pivotal therapeutic, but rarely in diagnostic research, although it may save studies, time, and costs. The purpose of this paper was to demonstrate a group-sequential analysis strategy in an intra-observer study on quantitative FDG...

Dynamic analysis of the CTAR (constant temperature adsorption refrigeration) cycle

International Nuclear Information System (INIS)

Hassan, H.Z.; Mohamad, A.A.; Al-Ansary, H.A.; Alyousef, Y.M.

2014-01-01

The basic SAR (solar-driven adsorption refrigeration) machine is an intermittent cold production system. Recently, the CO-SAR (continuous operation solar-powered adsorption refrigeration) system is developed. The CO-SAR machine is based on the theoretical CTAR (constant temperature adsorption refrigeration) cycle in which the adsorption process takes place at a constant temperature that equals the ambient temperature. Practically, there should be a temperature gradient between the adsorption bed and the surrounding atmosphere to provide a driving potential for heat transfer. In the present study, the dynamic analysis of the CTAR cycle is developed. This analysis provides a comparison between the theoretical and the dynamic operation of the CTAR cycle. The developed dynamic model is based on the D-A adsorption equilibrium equation and the energy and mass balances in the adsorption reactor. Results obtained from the present work demonstrate that, the idealization of the constant temperature adsorption process in the theoretical CTAR cycle is not far from the real situation and can be approached. Furthermore, enhancing the heat transfer between the adsorption bed and the ambient during the bed pre-cooling process helps accelerating the heat rejection process from the adsorption reactor and therefore approaching the isothermal process. - Highlights: • The dynamic analysis of the CTAR (constant temperature adsorption refrigeration) cycle is developed. • The CTAR theoretical and dynamic cycles are compared. • The dynamic cycle approaches the ideal one by enhancing the bed precooling

Assessing Group Interaction with Social Language Network Analysis

Science.gov (United States)

Scholand, Andrew J.; Tausczik, Yla R.; Pennebaker, James W.

In this paper we discuss a new methodology, social language network analysis (SLNA), that combines tools from social language processing and network analysis to assess socially situated working relationships within a group. Specifically, SLNA aims to identify and characterize the nature of working relationships by processing artifacts generated with computer-mediated communication systems, such as instant message texts or emails. Because social language processing is able to identify psychological, social, and emotional processes that individuals are not able to fully mask, social language network analysis can clarify and highlight complex interdependencies between group members, even when these relationships are latent or unrecognized.

AER working group D on WWER safety analysis - report of the 2007 meeting

International Nuclear Information System (INIS)

Kliem, S.

2007-01-01

The AER working group D on WWER reactor safety analysis held its sixteenth meeting in Paris, France during the period 08-09 May 2007. The meeting was hosted by the CEA France. It followed the final workshop on the OECD/DOE/CEA WWER-1000 Coolant Transient Benchmark held at 07 May. Altogether 11 participants attend the meeting of the working group D, 7 from AER member organizations and 4 guests from non-member organizations. The co-ordinator of the working group, Mr. S. Kliem, served as chairman of the meeting. The meeting started with a general information exchange about the recent activities in the participating organizations. The given presentations and the discussions can be attributed to the following topics: -Code development and benchmarking for reactor dynamics applications; -Safety analysis methodology and results; -Future activities. New solutions for three different benchmarks were presented and discussed. These are the Second AER Dynamic Benchmark on control rod ejection at hot zero power (S. Kliem, FZD), the WWER-1000 Coolant Transient Benchmark (E. Syrjaelahti, VTT) and the stationary AER-FCM101 Benchmark considering a WWER-1000 reactor (C. Parisi, UniPisa). A. Kereszturi (AEKI) presented a statistical evaluation of the possibility to observe a fuel assembly mis loading event. The second presentation of E. Syrjaelahti was dedicated to the description how best-estimate coupled code calculations at VTT are supported by uncertainty and sensitivity analyses. K. Velkov (GRS) presented preliminary results of BIPR8KN/ATHLET calculations with a very detailed resolution of the calculation grid on the assessment of coolant mixing inside WWER-1000 assembly heads. Coolant mixing experiments at three different mixing test facilities, modeling different reactor types, were presented and compared by S. Kliem. A calculation study using the coupled code system KORSAR/GP on the consequences of the injection of a slug of un borated water into the reactor core was

Design and analysis of diaphragms in dynamic microphones

Directory of Open Access Journals (Sweden)

Zi-Gui Huang

2015-07-01

Full Text Available Most contemporary high-end microphones are dynamic microphones, adopting the most basic electromagnetic transduction principles. This study investigated the diaphragm structures of dynamic microphones. The diaphragms were composed of polyimide material, and the boundary settings required for actual operation were provided using finite element model analysis software. The characteristic frequencies caused by grooving variations on the three-dimensional diaphragm were analyzed for the various groove shapes and number. The groove angles and width variations were examined based on the optimal groove shape selected in the aforementioned analysis, and the effects of these shapes were determined based on the analytical results. Acoustic waves cause thin films to vibrate, forming the working principle behind dynamic microphones. The thin film drives a coil to vibrate in a magnetic field and cuts the line of magnetic force, subsequently producing a voltage on both ends of the coil. This audio-frequency-inducted voltage represents an acoustic wave message. The finite element model analysis software was used to conduct electromagnetic induction simulations; the sound source was fed to the diaphragm to drive the coil. The coil vibrations caused the line of magnetic force to be cut, and the final voltages produced were examined and compared.

'AER Working Group D On WWER Safety Analysis' Report Of The Meeting In Pisa, Italy, 26-27 April 2006

International Nuclear Information System (INIS)

Siltanen, P.

2006-01-01

AER Working Group D on WWER reactor safety analysis held its 15 t h meeting in Grand Hotel Duomo in Pisa, Italy during the period 26-27 April 2006. The meeting was hosted by the University of Pisa following the fourth workshop on the OECD/DOE/CEA WWER-1000 Coolant Transient Benchmark (W1000-CT) held at the same location on 24-25 April. Altogether 15 participants attended the Working Group D meeting, 11 from AER member organizations and 4 guests from non-member organizations. The coordinator for the working group, Mr. P. Siltanen (FNS) served as chairman. In addition to general information exchange on recent activities in the participating organizations, the topics of the meeting included: 1) Code development and benchmarking for reactor dynamics applications. 2) Safety analysis methodology and results. 3) Future activities. A list of participants and a list of handouts distributed at the meeting are attached to the report (Author)

[Monochromatic aberration in accommodation. Dynamic wavefront analysis].

Science.gov (United States)

Fritzsch, M; Dawczynski, J; Jurkutat, S; Vollandt, R; Strobel, J

2011-06-01

Monochromatic aberrations may influence the visual acuity of the eye. They are not stable and can be affected by different factors. The subject of the following paper is the dynamic investigation of the changes in wavefront aberration with accommodation. Dynamic measurement of higher and lower order aberrations was performed with a WASCA Wavefront Analyzer (Carl-Zeiss-Meditec) and a specially constructed target device for aligning objects in far and near distances on 25 subjects aged from 15 to 27 years old. Wavefront aberrations showed some significant changes in accommodation. In addition to the characteristic sphere reaction accompanying miosis and changes in horizontal prism (Z(1) (1)) in the sense of a convergence movement of the eyeball also occurred. Furthermore defocus rose (Z(2) (0)) and astigmatism (Z(2) (-2)) changed. In higher-order aberrations a decrease in coma-like Zernike polynomials (Z(3) (-1), Z(3) (1)) was found. The most obvious change appeared in spherical aberration (Z(4) (0)) which increased and changed from positive to negative. In addition the secondary astigmatism (Z(4) (-2)) and quadrafoil (Z(4) (4)) rise also increased. The total root mean square (RMS), as well as the higher-order aberrations (RMS-HO) significantly increased in accommodation which is associated with a theoretical reduction of visual acuity. An analysis of the influence of pupil size on aberrations showed significant increases in defocus, spherical aberration, quadrafoil, RMS and RMS HO by increasing pupil diameter. By accommodation-associated miosis, the growing aberrations are partially compensated by focusing on near objects. Temporal analysis of the accommodation process with dynamic wavefront analysis revealed significant delays in pupil response and changing of prism in relation to the sphere reaction. In accommodation to near objects a discrete time ahead of third order aberrations in relation to the sphere response was found. Using dynamic wavefront measurement

Geometric group theory

CERN Document Server

Bestvina, Mladen; Vogtmann, Karen

2014-01-01

Geometric group theory refers to the study of discrete groups using tools from topology, geometry, dynamics and analysis. The field is evolving very rapidly and the present volume provides an introduction to and overview of various topics which have played critical roles in this evolution. The book contains lecture notes from courses given at the Park City Math Institute on Geometric Group Theory. The institute consists of a set of intensive short courses offered by leaders in the field, designed to introduce students to exciting, current research in mathematics. These lectures do not duplicate standard courses available elsewhere. The courses begin at an introductory level suitable for graduate students and lead up to currently active topics of research. The articles in this volume include introductions to CAT(0) cube complexes and groups, to modern small cancellation theory, to isometry groups of general CAT(0) spaces, and a discussion of nilpotent genus in the context of mapping class groups and CAT(0) gro...

Process Analysis of the CV Group's Operation

CERN Document Server

Wilhelmsson, M

2000-01-01

This report will give an explanation of the internal reorganization that has been done because of the necessity to optimize operation in the cooling and ventilation group. The basic structure for the group was defined at the end of 1998. We understood then that change was needed to accommodate the increased workload due to the LHC project. In addition, we face a relatively large turnover of personnel (retirements and some recruitment) with related integration issues to consider. We would also like to implement new approaches in the management of both operations and maintenance. After some running-in problems during the first half of 1999, we realized that much more could be gained with the analysis and the definition and documenting of each single function and generic activity within the group. The authors will explain how this analysis was carried out and give some feedback of the outcome, so far.

Harmonic analysis on exponential solvable Lie groups

CERN Document Server

Fujiwara, Hidenori

2015-01-01

This book is the first one that brings together recent results on the harmonic analysis of exponential solvable Lie groups. There still are many interesting open problems, and the book contributes to the future progress of this research field. As well, various related topics are presented to motivate young researchers. The orbit method invented by Kirillov is applied to study basic problems in the analysis on exponential solvable Lie groups. This method tells us that the unitary dual of these groups is realized as the space of their coadjoint orbits. This fact is established using the Mackey theory for induced representations, and that mechanism is explained first. One of the fundamental problems in the representation theory is the irreducible decomposition of induced or restricted representations. Therefore, these decompositions are studied in detail before proceeding to various related problems: the multiplicity formula, Plancherel formulas, intertwining operators, Frobenius reciprocity, and associated alge...

Combinatorial-topological framework for the analysis of global dynamics

Science.gov (United States)

Bush, Justin; Gameiro, Marcio; Harker, Shaun; Kokubu, Hiroshi; Mischaikow, Konstantin; Obayashi, Ippei; Pilarczyk, Paweł

2012-12-01

We discuss an algorithmic framework based on efficient graph algorithms and algebraic-topological computational tools. The framework is aimed at automatic computation of a database of global dynamics of a given m-parameter semidynamical system with discrete time on a bounded subset of the n-dimensional phase space. We introduce the mathematical background, which is based upon Conley's topological approach to dynamics, describe the algorithms for the analysis of the dynamics using rectangular grids both in phase space and parameter space, and show two sample applications.

Combinatorial-topological framework for the analysis of global dynamics.

Science.gov (United States)

Bush, Justin; Gameiro, Marcio; Harker, Shaun; Kokubu, Hiroshi; Mischaikow, Konstantin; Obayashi, Ippei; Pilarczyk, Paweł

2012-12-01

We discuss an algorithmic framework based on efficient graph algorithms and algebraic-topological computational tools. The framework is aimed at automatic computation of a database of global dynamics of a given m-parameter semidynamical system with discrete time on a bounded subset of the n-dimensional phase space. We introduce the mathematical background, which is based upon Conley's topological approach to dynamics, describe the algorithms for the analysis of the dynamics using rectangular grids both in phase space and parameter space, and show two sample applications.

Assessing the Internal Dynamics of Mathematical Problem Solving in Small Groups.

Science.gov (United States)

Artzt, Alice F.; Armour-Thomas, Eleanor

The purpose of this exploratory study was to examine the problem-solving behaviors and perceptions of (n=27) seventh-grade students as they worked on solving a mathematical problem within a small-group setting. An assessment system was developed that allowed for this analysis. To assess problem-solving behaviors within a small group a Group…

Vibrational properties of the amide group in acetanilide: A molecular-dynamics study

Science.gov (United States)

Campa, Alessandro; Giansanti, Andrea; Tenenbaum, Alexander

1987-09-01

A simplified classical model of acetanilide crystal is built in order to study the mechanisms of vibrational energy transduction in a hydrogen-bonded solid. The intermolecular hydrogen bond is modeled by an electrostatic interaction between neighboring excess charges on hydrogen and oxygen atoms. The intramolecular interaction in the peptide group is provided by a dipole-charge interaction. Forces are calculated up to second-order terms in the atomic displacements from equilibrium positions; the model is thus a chain of nonlinear coupled oscillators. Numerical molecular-dynamics experiments are performed on chain segments of five molecules. The dynamics is ordered, at all temperatures. Energy is widely exchanged between the stretching and the bending of the N-H bond, with characteristic times of the order of 0.2 ps. Energy transduction through the H bond is somewhat slower and of smaller amplitude, and is strongly reduced when the energies of the two bound molecules are very different: This could reduce the dissipation of localized energy fluctuations.

Conducting Qualitative Data Analysis: Managing Dynamic Tensions within

Science.gov (United States)

Chenail, Ronald J.

2012-01-01

In the third of a series of "how-to" essays on conducting qualitative data analysis, Ron Chenail examines the dynamic tensions within the process of qualitative data analysis that qualitative researchers must manage in order to produce credible and creative results. These tensions include (a) the qualities of the data and the qualitative data…

Dynamic response analysis as a tool for investigating transport mechanisms

International Nuclear Information System (INIS)

Dudok de Wit, Th.; Joye, B.; Lister, J.B.; Moret, J.M.

1990-01-01

Dynamic response analysis provides an attractive method for studying transport mechanisms in tokamak plasmas. The analysis of the radial response has already been widely used for heat and particle transport studies. The frequency dependence of the dynamic response, which is often omitted, reveals further properties of the dominant transport mechanisms. Extended measurements of the soft X-ray emission were carried out on the TCA tokamak in order to determine the underlying transport processes. (author) 5 refs., 2 figs

Critical Dynamics of the Xy-Model on the One-Dimensional Superlattice by Position Space Renormalization Group

Science.gov (United States)

Lima, J. P. De; Gonçalves, L. L.

The critical dynamics of the isotropic XY-model on the one-dimensional superlattice is considered in the framework of the position space renormalization group theory. The decimation transformation is introduced by considering the equations of motion of the operators associated to the excitations of the system, and it corresponds to an extension of the procedure introduced by Stinchcombe and dos Santos (J. Phys. A18, L597 (1985)) for the homogeneous lattice. The dispersion relation is obtained exactly and the static and dynamic scaling forms are explicitly determined. The dynamic critical exponent is also obtained and it is shown that it is identical to the one of the XY-model on the homogeneous chain.

Moderate intra-group bias maximizes cooperation on interdependent populations.

Directory of Open Access Journals (Sweden)

Changbing Tang

Full Text Available Evolutionary game theory on spatial structures has received increasing attention during the past decades. However, the majority of these achievements focuses on single and static population structures, which is not fully consistent with the fact that real structures are composed of many interactive groups. These groups are interdependent on each other and present dynamical features, in which individuals mimic the strategy of neighbors and switch their partnerships continually. It is however unclear how the dynamical and interdependent interactions among groups affect the evolution of collective behaviors. In this work, we employ the prisoner's dilemma game to investigate how the dynamics of structure influences cooperation on interdependent populations, where populations are represented by group structures. It is found that the more robust the links between cooperators (or the more fragile the links between cooperators and defectors, the more prevalent of cooperation. Furthermore, theoretical analysis shows that the intra-group bias can favor cooperation, which is only possible when individuals are likely to attach neighbors within the same group. Yet, interestingly, cooperation can be even inhibited for large intra-group bias, allowing the moderate intra-group bias maximizes the cooperation level.

Study on dynamic behavior analysis of towed line array sensor

Directory of Open Access Journals (Sweden)

Hyun Kyoung Shin

2012-03-01

Full Text Available A set of equations of motion is derived for vibratory motions of an underwater cable connected to a moving vehicle at one end and with drogues at the other end. From the static analysis, cable configurations are obtained for different vehicle speeds and towing pretensions are determined by fluid resistance of drogues. Also the dynamic analysis is required to predict its vibratory motion. Nonlinear fluid drag forces greatly influence the dynamic tension. In this study, a numerical analysis program was developed to find out the characteristic of cable behaviour. The motion is described in terms of space and time coordinates based on Chebyshev polynomial expansions. For the spatial integration the collocation method is employed and the Newmark method is applied for the time integration. Dynamic tensions, displacements, velocities, accelerations were predicted in the time domain while natural frequencies and transfer functions were obtained in the frequency domain.

Dimensional analysis and group theory in astrophysics

CERN Document Server

Kurth, Rudolf

2013-01-01

Dimensional Analysis and Group Theory in Astrophysics describes how dimensional analysis, refined by mathematical regularity hypotheses, can be applied to purely qualitative physical assumptions. The book focuses on the continuous spectral of the stars and the mass-luminosity relationship. The text discusses the technique of dimensional analysis, covering both relativistic phenomena and the stellar systems. The book also explains the fundamental conclusion of dimensional analysis, wherein the unknown functions shall be given certain specified forms. The Wien and Stefan-Boltzmann Laws can be si

Sensitivity analysis of reactive ecological dynamics.

Science.gov (United States)

Verdy, Ariane; Caswell, Hal

2008-08-01

Ecological systems with asymptotically stable equilibria may exhibit significant transient dynamics following perturbations. In some cases, these transient dynamics include the possibility of excursions away from the equilibrium before the eventual return; systems that exhibit such amplification of perturbations are called reactive. Reactivity is a common property of ecological systems, and the amplification can be large and long-lasting. The transient response of a reactive ecosystem depends on the parameters of the underlying model. To investigate this dependence, we develop sensitivity analyses for indices of transient dynamics (reactivity, the amplification envelope, and the optimal perturbation) in both continuous- and discrete-time models written in matrix form. The sensitivity calculations require expressions, some of them new, for the derivatives of equilibria, eigenvalues, singular values, and singular vectors, obtained using matrix calculus. Sensitivity analysis provides a quantitative framework for investigating the mechanisms leading to transient growth. We apply the methodology to a predator-prey model and a size-structured food web model. The results suggest predator-driven and prey-driven mechanisms for transient amplification resulting from multispecies interactions.

Integrability of dynamical systems algebra and analysis

CERN Document Server

Zhang, Xiang

2017-01-01

This is the first book to systematically state the fundamental theory of integrability and its development of ordinary differential equations with emphasis on the Darboux theory of integrability and local integrability together with their applications. It summarizes the classical results of Darboux integrability and its modern development together with their related Darboux polynomials and their applications in the reduction of Liouville and elementary integrabilty and in the center—focus problem, the weakened Hilbert 16th problem on algebraic limit cycles and the global dynamical analysis of some realistic models in fields such as physics, mechanics and biology. Although it can be used as a textbook for graduate students in dynamical systems, it is intended as supplementary reading for graduate students from mathematics, physics, mechanics and engineering in courses related to the qualitative theory, bifurcation theory and the theory of integrability of dynamical systems.

Substitution dynamical systems spectral analysis

CERN Document Server

Queffélec, Martine

2010-01-01

This volume mainly deals with the dynamics of finitely valued sequences, and more specifically, of sequences generated by substitutions and automata. Those sequences demonstrate fairly simple combinatorical and arithmetical properties and naturally appear in various domains. As the title suggests, the aim of the initial version of this book was the spectral study of the associated dynamical systems: the first chapters consisted in a detailed introduction to the mathematical notions involved, and the description of the spectral invariants followed in the closing chapters. This approach, combined with new material added to the new edition, results in a nearly self-contained book on the subject. New tools - which have also proven helpful in other contexts - had to be developed for this study. Moreover, its findings can be concretely applied, the method providing an algorithm to exhibit the spectral measures and the spectral multiplicity, as is demonstrated in several examples. Beyond this advanced analysis, many...

Dynamic stability and bifurcation analysis in fractional thermodynamics

Science.gov (United States)

Béda, Péter B.

2018-02-01

In mechanics, viscoelasticity was the first field of applications in studying geomaterials. Further possibilities arise in spatial non-locality. Non-local materials were already studied in the 1960s by several authors as a part of continuum mechanics and are still in focus of interest because of the rising importance of materials with internal micro- and nano-structure. When material instability gained more interest, non-local behavior appeared in a different aspect. The problem was concerned to numerical analysis, because then instability zones exhibited singular properties for local constitutive equations. In dynamic stability analysis, mathematical aspects of non-locality were studied by using the theory of dynamic systems. There the basic set of equations describing the behavior of continua was transformed to an abstract dynamic system consisting of differential operators acting on the perturbation field variables. Such functions should satisfy homogeneous boundary conditions and act as indicators of stability of a selected state of the body under consideration. Dynamic systems approach results in conditions for cases, when the differential operators have critical eigenvalues of zero real parts (dynamic stability or instability conditions). When the critical eigenvalues have non-trivial eigenspace, the way of loss of stability is classified as a typical (or generic) bifurcation. Our experiences show that material non-locality and the generic nature of bifurcation at instability are connected, and the basic functions of the non-trivial eigenspace can be used to determine internal length quantities of non-local mechanics. Fractional calculus is already successfully used in thermo-elasticity. In the paper, non-locality is introduced via fractional strain into the constitutive relations of various conventional types. Then, by defining dynamic systems, stability and bifurcation are studied for states of thermo-mechanical solids. Stability conditions and genericity

Financial Analysis on the example of Audi Group

OpenAIRE

Maltseva, Anna

2015-01-01

The aim of this master thesis is a financial analysis of Audi Group. Audi is one of the most popular brand of premium car manufacturers, which has a long history and which is a part of one of the biggest world groups in automotive industry -- Volkswagen Group. In this paper we will look into its financial reports in order to analyze its financial performance and make the conclusion in the end -- is Audi Group successful?

How groups cope with collective responsibility for ecological problems: Symbolic coping and collective emotions.

Science.gov (United States)

Caillaud, Sabine; Bonnot, Virginie; Ratiu, Eugenia; Krauth-Gruber, Silvia

2016-06-01

This study explores the way groups cope with collective responsibility for ecological problems. The social representations approach was adopted, and the collective symbolic coping model was used as a frame of analysis, integrating collective emotions to enhance the understanding of coping processes. The original feature of this study is that the analysis is at group level. Seven focus groups were conducted with French students. An original use of focus groups was proposed: Discussions were structured to induce feelings of collective responsibility and enable observation of how groups cope with such feelings at various levels (social knowledge; social identities; group dynamics). Two analyses were conducted: Qualitative analysis of participants' use of various kinds of knowledge, social categories and the group dynamics, and lexicometric analysis to reveal how emotions varied during the different discussion phases. Results showed that groups' emotional states moved from negative to positive: They used specific social categories and resorted to shared stereotypes to cope with collective responsibility and maintain the integrity of their worldview. Only then did debate become possible again; it was anchored in the nature-culture dichotomy such that groups switched from group-based to system-based emotions. © 2015 The British Psychological Society.

Time-dependent spectral analysis of interactions within groups of walking pedestrians and vertical structural motion using wavelets

Science.gov (United States)

Bocian, M.; Brownjohn, J. M. W.; Racic, V.; Hester, D.; Quattrone, A.; Gilbert, L.; Beasley, R.

2018-05-01

A multi-scale and multi-object interaction phenomena can arise when a group of walking pedestrians crosses a structure capable of exhibiting dynamic response. This is because each pedestrian is an autonomous dynamic system capable of displaying intricate behaviour affected by social, psychological, biomechanical and environmental factors, including adaptations to the structural motion. Despite a wealth of mathematical models attempting to describe and simulate coupled crowd-structure system, their applicability can generally be considered uncertain. This can be assigned to a number of assumptions made in their development and the scarcity or unavailability of data suitable for their validation, in particular those associated with pedestrian-pedestrian and pedestrian-structure interaction. To alleviate this problem, data on behaviour of individual pedestrians within groups of six walkers with different spatial arrangements are gathered simultaneously with data on dynamic structural response of a footbridge, from a series of measurements utilising wireless motion monitors. Unlike in previous studies on coordination of pedestrian behaviour, the collected data can serve as a proxy for pedestrian vertical force, which is of critical importance from the point of view of structural stability. A bivariate analysis framework is proposed and applied to these data, encompassing wavelet transform, synchronisation measures based on Shannon entropy and circular statistics. A topological pedestrian map is contrived showing the strength and directionality of between-subjects interactions. It is found that the coordination in pedestrians' vertical force depends on the spatial collocation within a group, but it is generally weak. The relationship between the bridge and pedestrian behaviour is also analysed, revealing stronger propensity for pedestrians to coordinate their force with the structural motion rather than with each other.

Efficiency Analysis of a Wave Power Generation System by Using Multibody Dynamics

International Nuclear Information System (INIS)

Kim, Min Soo; Sohn, Jeong Hyun; Kim, Jung Hee; Sung, Yong Jun

2016-01-01

The energy absorption efficiency of a wave power generation system is calculated as the ratio of the wave power to the power of the system. Because absorption efficiency depends on the dynamic behavior of the wave power generation system, a dynamic analysis of the wave power generation system is required to estimate the energy absorption efficiency of the system. In this study, a dynamic analysis of the wave power generation system under wave loads is performed to estimate the energy absorption efficiency. RecurDyn is employed to carry out the dynamic analysis of the system, and the Morison equation is used for the wave load model. According to the results, the lower the wave height and the shorter the period, the higher is the absorption efficiency of the system

Efficiency Analysis of a Wave Power Generation System by Using Multibody Dynamics

Energy Technology Data Exchange (ETDEWEB)

Kim, Min Soo; Sohn, Jeong Hyun [Pukyong National Univ., Busan (Korea, Republic of); Kim, Jung Hee; Sung, Yong Jun [INGINE Inc., Seoul (Korea, Republic of)

2016-06-15

The energy absorption efficiency of a wave power generation system is calculated as the ratio of the wave power to the power of the system. Because absorption efficiency depends on the dynamic behavior of the wave power generation system, a dynamic analysis of the wave power generation system is required to estimate the energy absorption efficiency of the system. In this study, a dynamic analysis of the wave power generation system under wave loads is performed to estimate the energy absorption efficiency. RecurDyn is employed to carry out the dynamic analysis of the system, and the Morison equation is used for the wave load model. According to the results, the lower the wave height and the shorter the period, the higher is the absorption efficiency of the system.

ANALYSIS AND OPTIMISATION OF DYNAMIC STABILITY OF MOBILE WORKING MACHINES

Directory of Open Access Journals (Sweden)

Peter BIGOŠ

2014-09-01

Full Text Available This paper describes an investigation of the dynamic stability, which is specified for the mobile working machines. There are presented the basic theoretical principles of the stability theory together with an introduction of two illustrative examples of the dynamic stability analysis.

Group-wise Principal Component Analysis for Exploratory Data Analysis

NARCIS (Netherlands)

Camacho, J.; Rodriquez-Gomez, Rafael A.; Saccenti, E.

2017-01-01

In this paper, we propose a new framework for matrix factorization based on Principal Component Analysis (PCA) where sparsity is imposed. The structure to impose sparsity is defined in terms of groups of correlated variables found in correlation matrices or maps. The framework is based on three new

Dynamic virtual fixture on the Euclidean group for admittance-type manipulator in deforming environments.

Science.gov (United States)

Zhang, Dongwen; Zhu, Qingsong; Xiong, Jing; Wang, Lei

2014-04-27

In a deforming anatomic environment, the motion of an instrument suffers from complex geometrical and dynamic constraints, robot assisted minimally invasive surgery therefore requires more sophisticated skills for surgeons. This paper proposes a novel dynamic virtual fixture (DVF) to enhance the surgical operation accuracy of admittance-type medical robotics in the deforming environment. A framework for DVF on the Euclidean Group SE(3) is presented, which unites rotation and translation in a compact form. First, we constructed the holonomic/non-holonomic constraints, and then searched for the corresponded reference to make a distinction between preferred and non-preferred directions. Second, different control strategies are employed to deal with the tasks along the distinguished directions. The desired spatial compliance matrix is synthesized from an allowable motion screw set to filter out the task unrelated components from manual input, the operator has complete control over the preferred directions; while the relative motion between the surgical instrument and the anatomy structures is actively tracked and cancelled, the deviation relative to the reference is compensated jointly by the operator and DVF controllers. The operator, haptic device, admittance-type proxy and virtual deforming environment are involved in a hardware-in-the-loop experiment, human-robot cooperation with the assistance of DVF controller is carried out on a deforming sphere to simulate beating heart surgery, performance of the proposed DVF on admittance-type proxy is evaluated, and both human factors and control parameters are analyzed. The DVF can improve the dynamic properties of human-robot cooperation in a low-frequency (0 ~ 40 rad/sec) deforming environment, and maintain synergy of orientation and translation during the operation. Statistical analysis reveals that the operator has intuitive control over the preferred directions, human and the DVF controller jointly control the

Growth conditions of 0-group plaice Pleuronectes platessa in the western Wadden Sea as revealed by otolith microstructure analysis

Science.gov (United States)

Cardoso, Joana F. M. F.; Freitas, Vânia; de Paoli, Hélène; Witte, Johannes IJ.; van der Veer, Henk W.

2016-05-01

Growth studies based on population-based growth estimates are limited by the fact that they do not take into account differences in age/size structure within the population. To overcome these problems, otolith microstructure analysis is often used to estimate individual growth. Here, we analyse growth of 0-group plaice in the western Wadden Sea in two years: a year preceded by a mild winter (1995) and a year preceded by a severe winter (1996). Growth was analysed by combining information on individual growth based on otolith analysis with predictions of maximum growth (= under optimal food conditions) based on a Dynamic Energy Budget model. Otolith analysis revealed that settlement occurred earlier in 1995 than in 1996. In both years, one main cohort was found, followed by a group of late settlers. No differences in mean length-at-age were found between these groups. DEB modelling suggested that growth was not maximal during the whole growing season: realized growth (the fraction of maximum growth realized by 0-group plaice) declined in the summer, although this decline was relatively small. In addition, late settling individuals exhibited lower realized growth than individuals from the main cohort. This study confirms that growth conditions for 0-group plaice are not optimal and that a growth reduction occurs in summer, as suggested in previous studies.

Problem Based Learning as a Shared Musical Journey – Group Dynamics, Communication and Creativity

Directory of Open Access Journals (Sweden)

Charlotte Lindvang

2015-06-01

Full Text Available The focus of this paper is how we can facilitate problem based learning (PBL more creatively. We take a closer look upon the connection between creative processes and social communication in the PBL group including how difficulties in the social interplay may hinder creativity. The paper draws on group dynamic theory, and points out the importance of building a reflexive milieu in the group. Musical concepts are used to illustrate the communicative and creative aspects of PBL and the paper uses the analogy between improvising together and do a project work together. We also discuss the role of the supervisor in a PBL group process. Further we argue that creativity is rooted deep in our consciousness and connected to our ability to work with a flexible mind. In order to enhance the cohesion as well as the creativity of the group a model of music listening as a concrete intervention tool in PBL processes is proposed.

Pre-Mission Communication And Awareness Stratgies For Positive Group Functioning And Development: Analysis Of A Crew At The Mars Desert Research Station (MDRS) In Utah, USA

Science.gov (United States)

Allner, Matthew; Bishop, Sheryl; Gushin, Vadim; McKay, Chris; Rygalov, Vadim; Allner, Matthew

Introduction: Psychosocial group functioning has become an increased international focus of many space faring nations due to the recent shift in focus of colonizing the Moon and then preparing to travel to Mars and beyond. Purpose: This study investigates the effects of pre-mission communication and awareness strategies for positive group functioning in extreme environments as well as suggestive countermeasures to maintain positive group dynamic development in isolated and confined extreme (ICE) environments. The study is supported by both preand intra-mission management efforts, which included crewmember assessments at various mission phases (pre-, intra-, and end-mission). Methods: A six person heterogeneous American crew conducted a Mars simulation mission at the Mars Society's Mars Desert Research Station in Utah, USA in 2006 as part of a new NASA training program called Spaceward Bound. Participants were administered assessments of personality, personal and group identity/functioning, subjective stress, coping, and subjective motivation. All participants were also provided information (pre-mission) regarding past research and tendencies of group functioning, stressors, cognitive functioning, and mission mistakes from a mission phase analysis approach, to see if this would be a factor in positive group dynamic development. Results: Data collected and obtained by both assessment and journaling methods were both consistent and indicative of positive personalities desirable of expedition crews. Assessment data further indicated positive group cohesion and group interactions, along with supportive and strong leadership, all which led to positive personal and group experiences for crewmembers. Crewmembers all displayed low levels of competition while still reporting high motivation and satisfaction for the group dynamic development and the mission objectives that were completed. Journals kept by the crew psychologist indicated that crewmembers all felt that the pre

Dynamic Stabilization of Metal Oxide–Water Interfaces

Energy Technology Data Exchange (ETDEWEB)

McBriarty, Martin E.; von Rudorff, Guido Falk; Stubbs, Joanne; Eng, Peter; Blumberger, Jochen; Rosso, Kevin M.

2017-02-08

Metal oxide growth, dissolution, and redox reactivity depend on the structure and dynamics at the interface with aqueous solution. We present the most definitive analysis to date of the hydrated naturally abundant r-cut (11$\\bar{0}$2) termination of the iron oxide hematite (α-Fe₂O₃). In situ synchrotron X-ray scattering analysis reveals a ridged lateral arrangement of adsorbed water molecules hydrogen bonded to terminal aquo groups. Large-scale hybrid-functional density functional theory-based molecular dynamics (DFT-MD) simulations show how this structure is dynamically stabilized by picosecond exchange between aquo groups and adsorbed water, even under nominally dry conditions. Surface pKa prediction based on bond valence analysis suggests that water exchange may influence the proton transfer reactions associated with acid/base reactivity at the interface. Our findings rectify inconsistencies between existing models and may be extended to resolving more complex electrochemical phenomena at metal oxide-water interfaces.

Analysis of static and dynamic pile-soil-jacket behaviour

Energy Technology Data Exchange (ETDEWEB)

Azadi, Mohammad Reza Emami

1998-12-31

In the offshore industry, recent extreme storms, severe earthquakes and subsidence of the foundation of jacket platforms have shown that new models and methods must take into account the jacket- pile-soil foundation interaction as well as the non-linear dynamic performance/loading effects. This thesis begins with a review of the state of art pile-soil interaction model, recognizing that most existing pile-soil models have been established based on large diameter pile tests on specific sites. The need for site independent and mechanistic pile-soil interaction models led to the development of new (t-z) and (p-y) disk models. These are validated using the available database from recent large diameter pile tests in the North Sea and Gulf of Mexico. The established static disk models are applied for non-linear static analysis of the jacket-pile-soil system under extreme wave loading. Dynamic pile-soil interaction is studied and a new disk-cone model is developed for the non-linear and non-homogeneous soils. This model is applied to both surface and embedded disks in a soil layer with non-linear properties. Simplified non-linear as well as more complex analysis methods are used to study the dynamic response of the jacket platform under extreme sea and seismic loading. Ductility spectra analysis is introduced and used to study the dynamic performance of the jacket systems near collapse. Case studies are used to illustrate the effects of structural, foundation failure characteristics as well as dynamic loading effects on the overall performance of the jacket-pile-soil systems near ultimate collapse. 175 refs., 429 figs., 70 tabs.

Evaluating Dynamic Analysis Techniques for Program Comprehension

NARCIS (Netherlands)

Cornelissen, S.G.M.

2009-01-01

Program comprehension is an essential part of software development and software maintenance, as software must be sufficiently understood before it can be properly modified. One of the common approaches in getting to understand a program is the study of its execution, also known as dynamic analysis.

Neighborhood structure effects on the Dynamic response of soil-structure interaction by harmonic analysis

Directory of Open Access Journals (Sweden)

Pan Dan-guang

2015-01-01

Full Text Available For realizing the variation of structural dynamic characteristics due to neighbor structure in buildings group, the surface structure is idealized as an equivalent single degree of freedom system with rigid base whose site consists of a single homogeneous layer. Based on the model, a equivalent method on the equivalent seismic excitation is proposed. Then, the differences of seismic response and equivalent seismic input between soil - structure interaction (SSI system and structure -soil-structure interaction (SSSI system are investigated by harmonic analysis. The numerical results show that dynamic responses would be underestimated in SSSI system when the forcing frequencies are close to the Natural frequency if the effects of neighborhood structure were ignored. Neighborhood structure would make the translational displacement increase and rocking vibration decrease. When establishing an effective seismic input, it is necessary to consider the impact of inertia interaction.

Visual Analysis of Inclusion Dynamics in Two-Phase Flow.

Science.gov (United States)

Karch, Grzegorz Karol; Beck, Fabian; Ertl, Moritz; Meister, Christian; Schulte, Kathrin; Weigand, Bernhard; Ertl, Thomas; Sadlo, Filip

2018-05-01

In single-phase flow visualization, research focuses on the analysis of vector field properties. In two-phase flow, in contrast, analysis of the phase components is typically of major interest. So far, visualization research of two-phase flow concentrated on proper interface reconstruction and the analysis thereof. In this paper, we present a novel visualization technique that enables the investigation of complex two-phase flow phenomena with respect to the physics of breakup and coalescence of inclusions. On the one hand, we adapt dimensionless quantities for a localized analysis of phase instability and breakup, and provide detailed inspection of breakup dynamics with emphasis on oscillation and its interplay with rotational motion. On the other hand, we present a parametric tightly linked space-time visualization approach for an effective interactive representation of the overall dynamics. We demonstrate the utility of our approach using several two-phase CFD datasets.

Johnson Space Center's Risk and Reliability Analysis Group 2008 Annual Report

Science.gov (United States)

Valentine, Mark; Boyer, Roger; Cross, Bob; Hamlin, Teri; Roelant, Henk; Stewart, Mike; Bigler, Mark; Winter, Scott; Reistle, Bruce; Heydorn,Dick

2009-01-01

The Johnson Space Center (JSC) Safety & Mission Assurance (S&MA) Directorate s Risk and Reliability Analysis Group provides both mathematical and engineering analysis expertise in the areas of Probabilistic Risk Assessment (PRA), Reliability and Maintainability (R&M) analysis, and data collection and analysis. The fundamental goal of this group is to provide National Aeronautics and Space Administration (NASA) decisionmakers with the necessary information to make informed decisions when evaluating personnel, flight hardware, and public safety concerns associated with current operating systems as well as with any future systems. The Analysis Group includes a staff of statistical and reliability experts with valuable backgrounds in the statistical, reliability, and engineering fields. This group includes JSC S&MA Analysis Branch personnel as well as S&MA support services contractors, such as Science Applications International Corporation (SAIC) and SoHaR. The Analysis Group s experience base includes nuclear power (both commercial and navy), manufacturing, Department of Defense, chemical, and shipping industries, as well as significant aerospace experience specifically in the Shuttle, International Space Station (ISS), and Constellation Programs. The Analysis Group partners with project and program offices, other NASA centers, NASA contractors, and universities to provide additional resources or information to the group when performing various analysis tasks. The JSC S&MA Analysis Group is recognized as a leader in risk and reliability analysis within the NASA community. Therefore, the Analysis Group is in high demand to help the Space Shuttle Program (SSP) continue to fly safely, assist in designing the next generation spacecraft for the Constellation Program (CxP), and promote advanced analytical techniques. The Analysis Section s tasks include teaching classes and instituting personnel qualification processes to enhance the professional abilities of our analysts

Performance analysis and dynamic modeling of a single-spool turbojet engine

Science.gov (United States)

Andrei, Irina-Carmen; Toader, Adrian; Stroe, Gabriela; Frunzulica, Florin

2017-01-01

The purposes of modeling and simulation of a turbojet engine are the steady state analysis and transient analysis. From the steady state analysis, which consists in the investigation of the operating, equilibrium regimes and it is based on appropriate modeling describing the operation of a turbojet engine at design and off-design regimes, results the performance analysis, concluded by the engine's operational maps (i.e. the altitude map, velocity map and speed map) and the engine's universal map. The mathematical model that allows the calculation of the design and off-design performances, in case of a single spool turbojet is detailed. An in house code was developed, its calibration was done for the J85 turbojet engine as the test case. The dynamic modeling of the turbojet engine is obtained from the energy balance equations for compressor, combustor and turbine, as the engine's main parts. The transient analysis, which is based on appropriate modeling of engine and its main parts, expresses the dynamic behavior of the turbojet engine, and further, provides details regarding the engine's control. The aim of the dynamic analysis is to determine a control program for the turbojet, based on the results provided by performance analysis. In case of the single-spool turbojet engine, with fixed nozzle geometry, the thrust is controlled by one parameter, which is the fuel flow rate. The design and management of the aircraft engine controls are based on the results of the transient analysis. The construction of the design model is complex, since it is based on both steady-state and transient analysis, further allowing the flight path cycle analysis and optimizations. This paper presents numerical simulations for a single-spool turbojet engine (J85 as test case), with appropriate modeling for steady-state and dynamic analysis.

CONTIN XPCS: Software for Inverse Transform Analysis of X-Ray Photon Correlation Spectroscopy Dynamics.

Science.gov (United States)

Andrews, Ross N; Narayanan, Suresh; Zhang, Fan; Kuzmenko, Ivan; Ilavsky, Jan

2018-02-01

X-ray photon correlation spectroscopy (XPCS) and dynamic light scattering (DLS) both reveal dynamics using coherent scattering, but X-rays permit investigating of dynamics in a much more diverse array of materials. Heterogeneous dynamics occur in many such materials, and we showed how classic tools employed in analysis of heterogeneous DLS dynamics extend to XPCS, revealing additional information that conventional Kohlrausch exponential fitting obscures. This work presents the software implementation of inverse transform analysis of XPCS data called CONTIN XPCS, an extension of traditional CONTIN that accommodates dynamics encountered in equilibrium XPCS measurements.

AER Working Group D on VVER safety analysis minutes of the meeting in Rez, Czech Republic 18-20 May 1998

International Nuclear Information System (INIS)

Siltanen, P.

1998-01-01

AER Working Group D on VVER reactor safety analysis held its seventh meeting in Hotel Vltava in Rez near Prague during the period 18-20 May 1998. There were altogether 11 participants from 8 member organisations. The coordinator for the working group, Mr. P. Siltanen (IVO) served as chairman. In addition to the general information exchange on recent activities, the topics of the meeting included: First review of solutions to the 3-dimensional AER Dynamic Benchmark Problem No. 5 on a steam line break accident. This benchmark involves a break of the main steam header. Safety analysis of reactivity events. Recent code development work and fuel behaviour. Coolant mixing calculations and experiments related to diluted slugs. A list of participants and a list of handouts distributed at the meeting are attached to the minutes. (author)

Parametric dynamic analysis of a superconducting bearing system

Energy Technology Data Exchange (ETDEWEB)

Cansiz, A; Hasar, U C; Cam, B Ates [Electrical and Electronics Engineering Department, Ataturk University, Erzurum (Turkey); Gundogdu, Oe, E-mail: acansiz@atauni.edu.t [Mechanical Engineering Department, Ataturk University, Erzurum (Turkey)

2009-03-01

The dynamics of a disk-shaped permanent-magnet rotor levitated over a high-temperature superconductor is studied. The interaction between the rotor magnet and the superconductor is modelled by assuming the magnet to be a magnetic dipole and the superconductor as a diamagnetic material. In the magneto-mechanical analysis of the superconductor part, the frozen image concept is combined with the diamagnetic image and the damping in the system was neglected. The interaction potential of the system is the combination of magnetic and gravitational potential. From the dynamical analysis, the equations of motion of the permanent magnet are stated as a function of lateral, vertical and tilt directions. The vibration behaviour of the permanent magnet is analyzed with a numerical calculation obtained by the non-dimensionalized differential equations for small initial impulses.

Parametric dynamic analysis of a superconducting bearing system

International Nuclear Information System (INIS)

Cansiz, A; Hasar, U C; Cam, B Ates; Gundogdu, Oe

2009-01-01

The dynamics of a disk-shaped permanent-magnet rotor levitated over a high-temperature superconductor is studied. The interaction between the rotor magnet and the superconductor is modelled by assuming the magnet to be a magnetic dipole and the superconductor as a diamagnetic material. In the magneto-mechanical analysis of the superconductor part, the frozen image concept is combined with the diamagnetic image and the damping in the system was neglected. The interaction potential of the system is the combination of magnetic and gravitational potential. From the dynamical analysis, the equations of motion of the permanent magnet are stated as a function of lateral, vertical and tilt directions. The vibration behaviour of the permanent magnet is analyzed with a numerical calculation obtained by the non-dimensionalized differential equations for small initial impulses.

Use of one delayed-neutron precursor group in transient analysis

International Nuclear Information System (INIS)

Diamond, D.J.

1983-01-01

In most reactor dynamics calculations six groups of delayed-neutron precursors are usually accounted for. However, under certain circumstances it may be advantageous to simplify the calculation and utilize a single delayed-neutron group. The motivation for going to one precursor group is economy. For LWR transient codes that use point kinetics the equations are solved very rapidly and six precursor groups should always be used. However, codes with spatially dependent neutron kinetics are very long running and the use of one precursor group may save computer costs and not impair the accuracy of the results significantly. Furthermore, in some codes, the elimation of five presursor groups makes additional memory available which may be used to give a net increase in the accuracy of the calculations, e.g., by allowing for an increase in mesh density. In order to use one delayed neutron precursor group it is necessary to derive a single decay constant, 6 lambda-, which, along with the total (or one group) delayed neutron fraction β = Σ/sub i = 1/β/sub i/, will adequately describe the transeint precursor behavior. The present summary explains how a recommendation for lambda- was derived

Mechanical Properties and Fractographic Analysis of High Manganese Steels After Dynamic Deformation Tests

Directory of Open Access Journals (Sweden)

Jabłońska M.B.

2014-10-01

Full Text Available Since few years many research centres conducting research on the development of high-manganese steels for manufacturing of parts for automotive and railway industry. Some of these steels belong to the group of AHS possessing together with high strength a great plastic elongation, and an ideal uniform work hardening behavior. The article presents the dynamic mechanical properties of two types of high manganese austenitic steel with using a flywheel machine at room temperature with strain rates between 5×102÷3.5×103s?–1. It was found that the both studied steels exhibit a high sensitivity Rm to the strain rate. With increasing the strain rate from 5×102 to 3.5×103s?–1 the hardening dominates the process. The fracture analysis indicate that after dynamic test both steel is characterized by ductile fracture surfaces which indicate good plasticity of investigated steels.

Renormalization group for centrosymmetric gauge transformations of the dynamic motion for a Markov-ordered polymer chain

International Nuclear Information System (INIS)

Mikhailov, I.D.; Zhuravskii, L.V.

1987-01-01

A method is proposed for calculating the vibrational-state density averaged over all configurations for a polymer chain with Markov disorder. The method is based on using a group of centrally symmetric gauge transformations that reduce the dynamic matrix for along polymer chain to renormalized dynamic matrices for short fragments. The short-range order is incorporated exactly in the averaging procedure, while the long-range order is incorporated in the self-consistent field approximation. Results are given for a simple skeletal model for a polymer containing tacticity deviations of Markov type

The effect of continuous grouping of pigs in large groups on stress response and haematological parameters

DEFF Research Database (Denmark)

Damgaard, Birthe Marie; Studnitz, Merete; Jensen, Karin Hjelholt

2009-01-01

The consequences of an ‘all in-all out' static group of uniform age vs. a continuously dynamic group with litter introduction and exit every third week were examined with respect to stress response and haematological parameters in large groups of 60 pigs. The experiment included a total of 480 pigs...... from weaning at the age of 4 weeks to the age of 18 weeks after weaning. Limited differences were found in stress and haematological parameters between pigs in dynamic and static groups. The cortisol response to the stress test was increasing with the duration of the stress test in pigs from...... the dynamic group while it was decreasing in the static group. The health condition and the growth performance were reduced in the dynamic groups compared with the static groups. In the dynamic groups the haematological parameters indicated an activation of the immune system characterised by an increased...

The Reach-and-Evolve Algorithm for Reachability Analysis of Nonlinear Dynamical Systems

NARCIS (Netherlands)

P.J. Collins (Pieter); A. Goldsztejn

2008-01-01

htmlabstractThis paper introduces a new algorithm dedicated to the rigorous reachability analysis of nonlinear dynamical systems. The algorithm is initially presented in the context of discrete time dynamical systems, and then extended to continuous time dynamical systems driven by ODEs. In

Full Dynamic Analysis of Mooring Solution Candidates - First Iteration

DEFF Research Database (Denmark)

Thomsen, Jonas Bjerg; Ferri, Francesco

This report covers an initial full dynamic analysis of the mooring solutions for the four wave energy converters in the project “Mooring Solutions for Large Wave Energy Converters”. The analysis tends to provide the first understanding of the layouts and provide discussion on what parameters that...

Benefits Analysis of Multi-Center Dynamic Weather Routes

Science.gov (United States)

Sheth, Kapil; McNally, David; Morando, Alexander; Clymer, Alexis; Lock, Jennifer; Petersen, Julien

2014-01-01

Dynamic weather routes are flight plan corrections that can provide airborne flights more than user-specified minutes of flying-time savings, compared to their current flight plan. These routes are computed from the aircraft's current location to a flight plan fix downstream (within a predefined limit region), while avoiding forecasted convective weather regions. The Dynamic Weather Routes automation has been continuously running with live air traffic data for a field evaluation at the American Airlines Integrated Operations Center in Fort Worth, TX since July 31, 2012, where flights within the Fort Worth Air Route Traffic Control Center are evaluated for time savings. This paper extends the methodology to all Centers in United States and presents benefits analysis of Dynamic Weather Routes automation, if it was implemented in multiple airspace Centers individually and concurrently. The current computation of dynamic weather routes requires a limit rectangle so that a downstream capture fix can be selected, preventing very large route changes spanning several Centers. In this paper, first, a method of computing a limit polygon (as opposed to a rectangle used for Fort Worth Center) is described for each of the 20 Centers in the National Airspace System. The Future ATM Concepts Evaluation Tool, a nationwide simulation and analysis tool, is used for this purpose. After a comparison of results with the Center-based Dynamic Weather Routes automation in Fort Worth Center, results are presented for 11 Centers in the contiguous United States. These Centers are generally most impacted by convective weather. A breakdown of individual Center and airline savings is presented and the results indicate an overall average savings of about 10 minutes of flying time are obtained per flight.

Age-Related Decline in the Variation of Dynamic Functional Connectivity: A Resting State Analysis

Directory of Open Access Journals (Sweden)

Yuanyuan Chen

2017-06-01

Full Text Available Normal aging is typically characterized by abnormal resting-state functional connectivity (FC, including decreasing connectivity within networks and increasing connectivity between networks, under the assumption that the FC over the scan time was stationary. In fact, the resting-state FC has been shown in recent years to vary over time even within minutes, thus showing the great potential of intrinsic interactions and organization of the brain. In this article, we assumed that the dynamic FC consisted of an intrinsic dynamic balance in the resting brain and was altered with increasing age. Two groups of individuals (N = 36, ages 20–25 for the young group; N = 32, ages 60–85 for the senior group were recruited from the public data of the Nathan Kline Institute. Phase randomization was first used to examine the reliability of the dynamic FC. Next, the variation in the dynamic FC and the energy ratio of the dynamic FC fluctuations within a higher frequency band were calculated and further checked for differences between groups by non-parametric permutation tests. The results robustly showed modularization of the dynamic FC variation, which declined with aging; moreover, the FC variation of the inter-network connections, which mainly consisted of the frontal-parietal network-associated and occipital-associated connections, decreased. In addition, a higher energy ratio in the higher FC fluctuation frequency band was observed in the senior group, which indicated the frequency interactions in the FC fluctuations. These results highly supported the basis of abnormality and compensation in the aging brain and might provide new insights into both aging and relevant compensatory mechanisms.

Generic dynamic wind turbine models for power system stability analysis: A comprehensive review

DEFF Research Database (Denmark)

Honrubia-Escribano, A.; Gómez-Lázaro, E.; Fortmann, J.

2018-01-01

In recent years, international working groups, mainly from the International Electrotechnical Commission (IEC) and the Western Electricity Coordinating Council (WECC), have made a major effort to develop generic —also known as simplified or standard— dynamic wind turbine models to be used for power...... system stability analysis. These models are required by power system operators to conduct the planning and operation activities of their networks since the use of detailed manufacturer models is not practical. This paper presents a comprehensive review of the work done in this field, based on the results...... obtained by IEC and WECC working groups in the course of their research, which have motivated the publication of the IEC 61400-27 in February 2015. The final published versions of the generic models developed according to the existing four wind turbine technology types are detailed, highlighting...

Analysis and Modeling of Control Tasks in Dynamic Systems

DEFF Research Database (Denmark)

Ursem, Rasmus Kjær; Krink, Thiemo; Jensen, Mikkel Thomas

2002-01-01

Most applications of evolutionary algorithms deal with static optimization problems. However, in recent years, there has been a growing interest in time-varying (dynamic) problems, which are typically found in real-world scenarios. One major challenge in this field is the design of realistic test......-case generators (TCGs), which requires a systematic analysis of dynamic optimization tasks. So far, only a few TCGs have been suggested. Our investigation leads to the conclusion that these TCGs are not capable of generating realistic dynamic benchmark tests. The result of our research is the design of a new TCG...

Conformation analysis of trehalose. Molecular dynamics simulation and molecular mechanics

International Nuclear Information System (INIS)

Donnamaira, M.C.; Howard, E.I.; Grigera, J.R.

1992-09-01

Conformational analysis of the disaccharide trehalose is done by molecular dynamics and molecular mechanics. In spite of the different force fields used in each case, comparison between the molecular dynamics trajectories of the torsional angles of glycosidic linkage and energy conformational map shows a good agreement between both methods. By molecular dynamics it is observed a moderate mobility of the glycosidic linkage. The demands of computer time is comparable in both cases. (author). 6 refs, 4 figs

Early Detection of Risk Taking in Groups and Individuals

Science.gov (United States)

2016-03-25

analysis  to   twitter  content  in  the... analysis  indicated  that   Twitter  messages  correspond  closely  in   tone  to  similarly  codified  results  from  news...Yardi, S., & Boyd, D. (2010). Dynamic debates: An analysis of group polarization over time on Twitter . Bulletin of Science, Technology &

Sensitivity analysis of dynamic characteristic of the fixture based on design variables

International Nuclear Information System (INIS)

Wang Dongsheng; Nong Shaoning; Zhang Sijian; Ren Wanfa

2002-01-01

The research on the sensitivity analysis is dealt with of structural natural frequencies to structural design parameters. A typical fixture for vibration test is designed. Using I-DEAS Finite Element programs, the sensitivity of its natural frequency to design parameters is analyzed by Matrix Perturbation Method. The research result shows that the sensitivity analysis is a fast and effective dynamic re-analysis method to dynamic design and parameters modification of complex structures such as fixtures

Peace and power: a theory of emancipatory group process.

Science.gov (United States)

Chinn, Peggy L; Falk-Rafael, Adeline

2015-01-01

To present the theoretical basis for the group process known as "Peace and Power." A dialectic between two dominant forms of power-peace powers and power-over powers-forms the basis for a synthesis that yields an emancipatory group process characterized by praxis, empowerment, awareness, cooperation, and evolvement for individuals and groups. Critical analysis of prevailing competitive group dynamics and the ideals of cooperative group dynamics was conducted to project the potential for achieving group interactions that yield profound changes in the direction of justice, empowerment, and well-being for all. The theoretical framework of "Peace and Power" is consistent with characteristics of emancipatory integrity that are vital for social change. The processes of "Peace and Power" can be used to create peaceful, cooperative interactions among nurses, with other health professionals, with patients and families, and in communities. © 2014 Sigma Theta Tau International.

Inverse Transformation: Unleashing Spatially Heterogeneous Dynamics with an Alternative Approach to XPCS Data Analysis.

Science.gov (United States)

Andrews, Ross N; Narayanan, Suresh; Zhang, Fan; Kuzmenko, Ivan; Ilavsky, Jan

2018-02-01

X-ray photon correlation spectroscopy (XPCS), an extension of dynamic light scattering (DLS) in the X-ray regime, detects temporal intensity fluctuations of coherent speckles and provides scattering vector-dependent sample dynamics at length scales smaller than DLS. The penetrating power of X-rays enables probing dynamics in a broad array of materials with XPCS, including polymers, glasses and metal alloys, where attempts to describe the dynamics with a simple exponential fit usually fails. In these cases, the prevailing XPCS data analysis approach employs stretched or compressed exponential decay functions (Kohlrausch functions), which implicitly assume homogeneous dynamics. In this paper, we propose an alternative analysis scheme based upon inverse Laplace or Gaussian transformation for elucidating heterogeneous distributions of dynamic time scales in XPCS, an approach analogous to the CONTIN algorithm widely accepted in the analysis of DLS from polydisperse and multimodal systems. Using XPCS data measured from colloidal gels, we demonstrate the inverse transform approach reveals hidden multimodal dynamics in materials, unleashing the full potential of XPCS.

Dynamical analysis of the global business-cycle synchronization.

Science.gov (United States)

Lopes, António M; Tenreiro Machado, J A; Huffstot, John S; Mata, Maria Eugénia

2018-01-01

This paper reports the dynamical analysis of the business cycles of 12 (developed and developing) countries over the last 56 years by applying computational techniques used for tackling complex systems. They reveal long-term convergence and country-level interconnections because of close contagion effects caused by bilateral networking exposure. Interconnectivity determines the magnitude of cross-border impacts. Local features and shock propagation complexity also may be true engines for local configuration of cycles. The algorithmic modeling proves to represent a solid approach to study the complex dynamics involved in the world economies.

Dynamical analysis of the global business-cycle synchronization

Science.gov (United States)

2018-01-01

This paper reports the dynamical analysis of the business cycles of 12 (developed and developing) countries over the last 56 years by applying computational techniques used for tackling complex systems. They reveal long-term convergence and country-level interconnections because of close contagion effects caused by bilateral networking exposure. Interconnectivity determines the magnitude of cross-border impacts. Local features and shock propagation complexity also may be true engines for local configuration of cycles. The algorithmic modeling proves to represent a solid approach to study the complex dynamics involved in the world economies. PMID:29408909

Single Molecule Cluster Analysis Identifies Signature Dynamic Conformations along the Splicing Pathway

Science.gov (United States)

Blanco, Mario R.; Martin, Joshua S.; Kahlscheuer, Matthew L.; Krishnan, Ramya; Abelson, John; Laederach, Alain; Walter, Nils G.

2016-01-01

The spliceosome is the dynamic RNA-protein machine responsible for faithfully splicing introns from precursor messenger RNAs (pre-mRNAs). Many of the dynamic processes required for the proper assembly, catalytic activation, and disassembly of the spliceosome as it acts on its pre-mRNA substrate remain poorly understood, a challenge that persists for many biomolecular machines. Here, we developed a fluorescence-based Single Molecule Cluster Analysis (SiMCAn) tool to dissect the manifold conformational dynamics of a pre-mRNA through the splicing cycle. By clustering common dynamic behaviors derived from selectively blocked splicing reactions, SiMCAn was able to identify signature conformations and dynamic behaviors of multiple ATP-dependent intermediates. In addition, it identified a conformation adopted late in splicing by a 3′ splice site mutant, invoking a mechanism for substrate proofreading. SiMCAn presents a novel framework for interpreting complex single molecule behaviors that should prove widely useful for the comprehensive analysis of a plethora of dynamic cellular machines. PMID:26414013

Scalable group level probabilistic sparse factor analysis

DEFF Research Database (Denmark)

Hinrich, Jesper Løve; Nielsen, Søren Føns Vind; Riis, Nicolai Andre Brogaard

2017-01-01

Many data-driven approaches exist to extract neural representations of functional magnetic resonance imaging (fMRI) data, but most of them lack a proper probabilistic formulation. We propose a scalable group level probabilistic sparse factor analysis (psFA) allowing spatially sparse maps, component...... pruning using automatic relevance determination (ARD) and subject specific heteroscedastic spatial noise modeling. For task-based and resting state fMRI, we show that the sparsity constraint gives rise to components similar to those obtained by group independent component analysis. The noise modeling...... shows that noise is reduced in areas typically associated with activation by the experimental design. The psFA model identifies sparse components and the probabilistic setting provides a natural way to handle parameter uncertainties. The variational Bayesian framework easily extends to more complex...

Tuning of electronic properties and dynamical stability of graphene oxide with different functional groups

Science.gov (United States)

Dabhi, Shweta D.; Jha, Prafulla K.

2017-09-01

The structural, electronic and vibrational properties of graphene oxide (GO) with varying proportion of epoxy and hydroxyl functional groups have been studied using density functional theory. The functional groups and oxygen density have an obvious influence on the electronic and vibrational properties. The dependence of band gap on associated functional groups and oxygen density shows a possibility of tuning the band gap of graphene by varying the functional groups as well as oxidation level. The absorption of high oxygen content in graphene leads to the gap opening and resulting in a transition from semimetal to semiconductor. Phonon dispersion curves show no imaginary frequency or no softening of any phonon mode throughout the Brillouin zone which confirms the dynamical stability of all considered GO models. Different groups and different oxygen density result into the varying characteristics of phonon modes. The computed results show good agreement with the experimental observations. Our results present interesting possibilities for engineering the electronic properties of graphene and GO and impact the fabrication of new electronics.

Application of System Dynamics Methodology in Population Analysis

Directory of Open Access Journals (Sweden)

August Turina

2009-09-01

Full Text Available The goal of this work is to present the application of system dynamics and system thinking, as well as the advantages and possible defects of this analytic approach, in order to improve the analysis of complex systems such as population and, thereby, to monitor more effectively the underlying causes of migrations. This methodology has long been present in interdisciplinary scientific circles, but its scientific contribution has not been sufficiently applied in analysis practice in Croatia. Namely, the major part of system analysis is focused on detailed complexity rather than on dynamic complexity. Generally, the science of complexity deals with emergence, innovation, learning and adaptation. Complexity is viewed according to the number of system components, or through a number of combinations that must be continually analyzed in order to understand and consequently provide adequate decisions. Simulations containing thousands of variables and complex arrays of details distract overall attention from the basic cause patterns and key inter-relations emerging and prevailing within an analyzed population. Systems thinking offers a holistic and integral perspective for observation of the world.

Elastic-plastic dynamic analysis of a reactor building

International Nuclear Information System (INIS)

Umemura, Hajime; Tanaka, Hiroshi.

1976-01-01

The basic characteristics of the dynamic response of a reactor building to severe earthquake ground motion are very important for the evaluation of the safety of nuclear plant systems. A computer program for elastic-plastic dynamic analysis of reactor buildings using lumped mass models is developed. The box and cylindrical walls of boiling water reactor buildings are treated as vertical beams. The nonlinear moment-rotation and shear force-shear deformation relationships of walls are based in part upon the experiments of prototype structures. The geometrical non-linearity of the soil rocking spring due to foundation separation is also considered. The nonlinear equation of motion is expressed in incremental form using tangent stiffness matrices, following the algorithm developed by E.L. Wilson et al. The damping matrix in the equation is formulated as the combination of the energy evaluation method and Penzien-Wilson's approach to accomodate the different characteristics of soil and building damping. The analysis examples and the comparison of elastic and elastic-plastic analysis results are presented. (auth.)

Learning dynamics in research alliances: A panel data analysis

NARCIS (Netherlands)

Duso, T.; Pennings, E.; Seldeslachts, J.

2010-01-01

The aim of this paper is to empirically test the determinants of Research Joint Ventures’ (RJVs) group dynamics. We develop a model based on learning and transaction cost theories, which represent the benefits and costs of RJV participation, respectively. According to our framework, firms at each

General Dynamics Convair Division approach to structural analysis of large superconducting coils

International Nuclear Information System (INIS)

Baldi, R.W.

1979-01-01

This paper describes the overall integrated analysis approach and highlights the results obtained. Most of the procedures and techniques described were developed over the past three years. Starting in late 1976, development began on high-accuracy computer codes for electromagnetic field and force analysis. This effort resulted in completion of a family of computer programs called MAGIC (MAGnetic Integration Calculation). Included in this group of programs is a post-processor called POSTMAGIC that links MAGIC to GDSAP (General Dynamics Structural Analysis Program) by automatically transferring force data. Integrating these computer programs afforded us the capability to readily analyze several different conditions that are anticipated to occur during tokamak operation. During 1977 we initiated the development of the CONVERT program that effectively links our THERMAL ANALYZER program to GDSAP by automatically transferring temperature data. The CONVERT program allowed us the capability to readily predict thermal stresses at several different time phases during the computer-simulated cooldown and warmup cycle. This feature aided us in determining the most crucial time phases and to adjust recommended operating procedure to minimize risk. (orig.)

Group sparse canonical correlation analysis for genomic data integration.

Science.gov (United States)

Lin, Dongdong; Zhang, Jigang; Li, Jingyao; Calhoun, Vince D; Deng, Hong-Wen; Wang, Yu-Ping

2013-08-12

The emergence of high-throughput genomic datasets from different sources and platforms (e.g., gene expression, single nucleotide polymorphisms (SNP), and copy number variation (CNV)) has greatly enhanced our understandings of the interplay of these genomic factors as well as their influences on the complex diseases. It is challenging to explore the relationship between these different types of genomic data sets. In this paper, we focus on a multivariate statistical method, canonical correlation analysis (CCA) method for this problem. Conventional CCA method does not work effectively if the number of data samples is significantly less than that of biomarkers, which is a typical case for genomic data (e.g., SNPs). Sparse CCA (sCCA) methods were introduced to overcome such difficulty, mostly using penalizations with l-1 norm (CCA-l1) or the combination of l-1and l-2 norm (CCA-elastic net). However, they overlook the structural or group effect within genomic data in the analysis, which often exist and are important (e.g., SNPs spanning a gene interact and work together as a group). We propose a new group sparse CCA method (CCA-sparse group) along with an effective numerical algorithm to study the mutual relationship between two different types of genomic data (i.e., SNP and gene expression). We then extend the model to a more general formulation that can include the existing sCCA models. We apply the model to feature/variable selection from two data sets and compare our group sparse CCA method with existing sCCA methods on both simulation and two real datasets (human gliomas data and NCI60 data). We use a graphical representation of the samples with a pair of canonical variates to demonstrate the discriminating characteristic of the selected features. Pathway analysis is further performed for biological interpretation of those features. The CCA-sparse group method incorporates group effects of features into the correlation analysis while performs individual feature

Do narcissism and emotional intelligence win us friends? : modeling dynamics of peer popularity using inferential network analysis

OpenAIRE

Czarna, Anna; Leifeld, Philip; Śmieja-Nęcka, Magdalena; Dufner, Michael; Salovey, Peter

2016-01-01

This research investigated effects of narcissism and emotional intelligence (EI) on popularity in social networks. In a longitudinal field study, we examined the dynamics of popularity in 15 peer groups in two waves (N = 273). We measured narcissism, ability EI, and explicit and implicit self-esteem. In addition, we measured popularity at zero acquaintance and 3 months later. We analyzed the data using inferential network analysis (temporal exponential random graph modeling, TERGM) accounting...

Analysis of vorticity dynamics for hump characteristics of a pump turbine model

Energy Technology Data Exchange (ETDEWEB)

Li, Deyou; Gong, Ruzhi; Wang, Hongjie; Han, Lei; Wei, Xianzhu; Qin, Daqing [School of Energy Science and Engineering, Harbin Institute of Technology, Harbin (China)

2016-08-15

Conventional parameters based on CFD methodology for the investigation on hump characteristics of a pump turbine cannot reflect the dynamic interaction mechanism between the runner and the fluid. This research presents a dynamic interaction mechanism of a pump turbine operating in the hump region. First, vorticity dynamic parameters were obtained based on the theory of vorticity dynamics. Second, 3-D unsteady flow simulations were performed in a full pump turbine model using the SST k-ω turbulence model, and numerical results have a good agreement with the experiments. Then, analysis was carried out to determine the relation between the vorticity dynamic parameters and hump characteristics. The results indicate that the theory of vorticity dynamics has an advantage in evaluating the dynamic performance of a pump turbine. The energy transfer between the runner and the fluid is through vorticity dynamic parameters-pressure and friction terms, in which the pressure term accounts for the most. Furthermore, vortex generation mainly results from the skin friction. Combining vorticity dynamic analysis with the method of Q-criterion indicates that hump characteristics are related to the reduction of the surface normal pressure work and vortex motion on the suction surfaces close to the leading edges in the runner, and the increase of skin friction work in the stay-guide vanes.

The hydrogen atom in a magnetic field. Spectrum from the Coulomb dynamical group approach

International Nuclear Information System (INIS)

Delande, D.; Gay, J.C.

1986-01-01

Some sample results are presented for the problems of the hydrogen atom in a magnetic field. The energies have been computed for a typical Rydberg situation of atomic physics interest using limited computer facilities. The use of the Coulomb dynamical group allows a complete description of the symmetries and a rational choice of a Sturmian type basis set. Moreover, comparison with Rayleigh-Schrodinger perturbative expansions of the energies is performed. (author)

Biomechanical Analysis and Evaluation Technology Using Human Multi-Body Dynamic Model

Energy Technology Data Exchange (ETDEWEB)

Kim, Yoon Hyuk; Shin, June Ho; Khurelbaatar, Tsolmonbaatar [Kyung Hee University, Yongin (Korea, Republic of)

2011-10-15

This paper presents the biomechanical analysis and evaluation technology of musculoskeletal system by multi-body human dynamic model and 3-D motion capture data. First, medical image based geometric model and material properties of tissue were used to develop the human dynamic model and 3-D motion capture data based motion analysis techniques were develop to quantify the in-vivo joint kinematics, joint moment, joint force, and muscle force. Walking and push-up motion was investigated using the developed model. The present model and technologies would be useful to apply the biomechanical analysis and evaluation of human activities.

Dynamic risk analysis using bow-tie approach

International Nuclear Information System (INIS)

Khakzad, Nima; Khan, Faisal; Amyotte, Paul

2012-01-01

Accident probability estimation is a common and central step to all quantitative risk assessment methods. Among many techniques available, bow-tie model (BT) is very popular because it represent the accident scenario altogether including causes and consequences. However, it suffers a static structure limiting its application in real-time monitoring and probability updating which are key factors in dynamic risk analysis. The present work is focused on using BT approach in a dynamic environment in which the occurrence probability of accident consequences changes. In this method, on one hand, failure probability of primary events of BT, leading to the top event, are developed using physical reliability models, and constantly revised as physical parameters (e.g., pressure, velocity, dimension, etc) change. And, on the other hand, the failure probability of safety barriers of the BT are periodically updated using Bayes’ theorem as new information becomes available over time. Finally, the resulting, updated BT is used to estimate the posterior probability of the consequences which in turn results in an updated risk profile. - Highlights: ► A methodology is proposed to make bow-tie method adapted for dynamic risk analysis. ► Physical reliability models are used to revise the top event. ► Bayes’ theorem is used to update the probability of safety barriers. ► The number of accidents in sequential time intervals is used to form likelihood function. ► The risk profile is updated for varying physical parameters and for different times.

Creation and Reliability Analysis of Vehicle Dynamic Weighing Model

Directory of Open Access Journals (Sweden)

Zhi-Ling XU

2014-08-01

Full Text Available In this paper, it is modeled by using ADAMS to portable axle load meter of dynamic weighing system, controlling a single variable simulation weighing process, getting the simulation weighing data under the different speed and weight; simultaneously using portable weighing system with the same parameters to achieve the actual measurement, comparative analysis the simulation results under the same conditions, at 30 km/h or less, the simulation value and the measured value do not differ by more than 5 %, it is not only to verify the reliability of dynamic weighing model, but also to create possible for improving algorithm study efficiency by using dynamic weighing model simulation.

Backtracing neutron analysis in the fusion-fission dynamics study

International Nuclear Information System (INIS)

Brennand, E. de Goes; Hanappe, F.; Stuttge, L.

2001-01-01

A new method for the analysis of multi parametric experimental data is used in the study of the dynamics of the fission process for the compound system 126 Ba. We apply this method to obtain the correlation between thermal energy related to the neutron total multiplicity and the correlation between pre-scission neutron and pos-scission neutron multiplicities. The results obtained are interpreted into the framework of a dynamical model. From this interpretation we have access to the following information: the friction intensity which drives the dynamical evolution of the system; the initial deformation of the compound system; the barrier evolution with temperature and angular momentum, and fission times. (author)

DyNet: visualization and analysis of dynamic molecular interaction networks.

Science.gov (United States)

Goenawan, Ivan H; Bryan, Kenneth; Lynn, David J

2016-09-01

: The ability to experimentally determine molecular interactions on an almost proteome-wide scale under different conditions is enabling researchers to move from static to dynamic network analysis, uncovering new insights into how interaction networks are physically rewired in response to different stimuli and in disease. Dynamic interaction data presents a special challenge in network biology. Here, we present DyNet, a Cytoscape application that provides a range of functionalities for the visualization, real-time synchronization and analysis of large multi-state dynamic molecular interaction networks enabling users to quickly identify and analyze the most 'rewired' nodes across many network states. DyNet is available at the Cytoscape (3.2+) App Store (http://apps.cytoscape.org/apps/dynet). david.lynn@sahmri.com Supplementary data are available at Bioinformatics online. © The Author 2016. Published by Oxford University Press.

Iterative analysis of cerebrovascular reactivity dynamic response by temporal decomposition.

Science.gov (United States)

van Niftrik, Christiaan Hendrik Bas; Piccirelli, Marco; Bozinov, Oliver; Pangalu, Athina; Fisher, Joseph A; Valavanis, Antonios; Luft, Andreas R; Weller, Michael; Regli, Luca; Fierstra, Jorn

2017-09-01

To improve quantitative cerebrovascular reactivity (CVR) measurements and CO 2 arrival times, we present an iterative analysis capable of decomposing different temporal components of the dynamic carbon dioxide- Blood Oxygen-Level Dependent (CO 2 -BOLD) relationship. Decomposition of the dynamic parameters included a redefinition of the voxel-wise CO 2 arrival time, and a separation from the vascular response to a stepwise increase in CO 2 (Delay to signal Plateau - DTP) and a decrease in CO 2 (Delay to signal Baseline -DTB). Twenty-five (normal) datasets, obtained from BOLD MRI combined with a standardized pseudo-square wave CO 2 change, were co-registered to generate reference atlases for the aforementioned dynamic processes to score the voxel-by-voxel deviation probability from normal range. This analysis is further illustrated in two subjects with unilateral carotid artery occlusion using these reference atlases. We have found that our redefined CO 2 arrival time resulted in the best data fit. Additionally, excluding both dynamic BOLD phases (DTP and DTB) resulted in a static CVR, that is maximal response, defined as CVR calculated only over a normocapnic and hypercapnic calibrated plateau. Decomposition and novel iterative modeling of different temporal components of the dynamic CO 2 -BOLD relationship improves quantitative CVR measurements.

Complex Dynamical Behaviors in a Predator-Prey System with Generalized Group Defense and Impulsive Control Strategy

Directory of Open Access Journals (Sweden)

Shunyi Li

2013-01-01

Full Text Available A predator-prey system with generalized group defense and impulsive control strategy is investigated. By using Floquet theorem and small amplitude perturbation skills, a local asymptotically stable prey-eradication periodic solution is obtained when the impulsive period is less than some critical value. Otherwise, the system is permanent if the impulsive period is larger than the critical value. By using bifurcation theory, we show the existence and stability of positive periodic solution when the pest eradication lost its stability. Numerical examples show that the system considered has more complicated dynamics, including (1 high-order quasiperiodic and periodic oscillation, (2 period-doubling and halving bifurcation, (3 nonunique dynamics (meaning that several attractors coexist, and (4 chaos and attractor crisis. Further, the importance of the impulsive period, the released amount of mature predators and the degree of group defense effect are discussed. Finally, the biological implications of the results and the impulsive control strategy are discussed.

Intrinsic Dynamics Analysis of a DNA Octahedron by Elastic Network Model

Directory of Open Access Journals (Sweden)

Guang Hu

2017-01-01

Full Text Available DNA is a fundamental component of living systems where it plays a crucial role at both functional and structural level. The programmable properties of DNA make it an interesting building block for the construction of nanostructures. However, molecular mechanisms for the arrangement of these well-defined DNA assemblies are not fully understood. In this paper, the intrinsic dynamics of a DNA octahedron has been investigated by using two types of Elastic Network Models (ENMs. The application of ENMs to DNA nanocages include the analysis of the intrinsic flexibilities of DNA double-helices and hinge sites through the calculation of the square fluctuations, as well as the intrinsic collective dynamics in terms of cross-collective map calculation coupled with global motions analysis. The dynamics profiles derived from ENMs have then been evaluated and compared with previous classical molecular dynamics simulation trajectories. The results presented here revealed that ENMs can provide useful insights into the intrinsic dynamics of large DNA nanocages and represent a useful tool in the field of structural DNA nanotechnology.

Comparative dynamic analysis of morbidity in various age groups in Russian Federation

Directory of Open Access Journals (Sweden)

Vera A. Pogodina

2016-09-01

Conclusion ― Rate of healthcare visits in Russian Federation was higher for children aged 0-14 years and population older than 18 years. Morbidity increase rate was higher in children aged 0-14 years and women older than 55 years and men older than 60 years. Structural differences in disease groups were detected, which may be taken into account when planning preventive measures according to population age.

Effect of glass-forming biopreservatives on head group rotational dynamics in freeze-dried phospholipid bilayers: A 31P NMR study

Science.gov (United States)

Jain, P.; Sen, S.; Risbud, S. H.

2009-07-01

P31 NMR spectroscopy has been used to elucidate the role of glass-forming sugars in the preservation of dipalmitoylphosphatidylcholine (DPPC) lipid bilayers. P31 wideline NMR spectra of freeze-dried pure DPPC, DPPC/trehalose, DPPC/glucose, and DPPC/hydroxyethyl starch (HES) mixtures collected in the temperature range of 25-80 °C have been simulated to obtain quantitative information about rotational dynamics and orientation of the lipid head groups in these media. In the case of pure DPPC, DPPC/glucose, and DPPC/HES, the gel-to-liquid crystalline phase transition of DPPC bilayer is characterized by a sudden increase in the rate of rotational diffusion of the PO4 head groups near 40 °C. The corresponding rotational jump frequency increases from a few kilohertz in the gel phase to at least several megahertz in the liquid crystalline phase. On the other hand, in the case of DPPC/trehalose mixture the temperature of this onset of rapid head group dynamics is increased by ˜10 °C. Trehalose reduces the lipid head group motions most effectively in the temperature range of T ≤50 °C relevant for biopreservation. Additionally, and possibly more importantly, trehalose is found to strongly restrict any change in the orientation of the diffusion axis of the PO4 head groups during the phase transformation. This unique ability of trehalose to maintain the dynamical and orientational rigidity of lipid head groups is likely to be responsible for its superior ability in biopreservation.

More dynamical supersymmetry breaking

International Nuclear Information System (INIS)

Csaki, C.; Randall, L.; Skiba, W.

1996-01-01

In this paper we introduce a new class of theories which dynamically break supersymmetry based on the gauge group SU(n) x SU(3) x U(1) for even n. These theories are interesting in that no dynamical superpotential is generated in the absence of perturbations. For the example SU(4) x SU(3) x U(1) we explicitly demonstrate that all flat directions can be lifted through a renormalizable superpotential and that supersymmetry is dynamically broken. We derive the exact superpotential for this theory, which exhibits new and interesting dynamical phenomena. For example, modifications to classical constraints can be field dependent. We also consider the generalization to SU(n) x SU(3) x U(1) models (with even n>4). We present a renormalizable superpotential which lifts all flat directions. Because SU(3) is not confining in the absence of perturbations, the analysis of supersymmetry breaking is very different in these theories from the n=4 example. When the SU(n) gauge group confines, the Yukawa couplings drive the SU(3) theory into a regime with a dynamically generated superpotential. By considering a simplified version of these theories we argue that supersymmetry is probably broken. (orig.)

Gaze distribution analysis and saliency prediction across age groups.

Science.gov (United States)

Krishna, Onkar; Helo, Andrea; Rämä, Pia; Aizawa, Kiyoharu

2018-01-01

Knowledge of the human visual system helps to develop better computational models of visual attention. State-of-the-art models have been developed to mimic the visual attention system of young adults that, however, largely ignore the variations that occur with age. In this paper, we investigated how visual scene processing changes with age and we propose an age-adapted framework that helps to develop a computational model that can predict saliency across different age groups. Our analysis uncovers how the explorativeness of an observer varies with age, how well saliency maps of an age group agree with fixation points of observers from the same or different age groups, and how age influences the center bias tendency. We analyzed the eye movement behavior of 82 observers belonging to four age groups while they explored visual scenes. Explorative- ness was quantified in terms of the entropy of a saliency map, and area under the curve (AUC) metrics was used to quantify the agreement analysis and the center bias tendency. Analysis results were used to develop age adapted saliency models. Our results suggest that the proposed age-adapted saliency model outperforms existing saliency models in predicting the regions of interest across age groups.

Intersection Group Dynamic Subdivision and Coordination at Intraregional Boundaries in Sudden Disaster

Directory of Open Access Journals (Sweden)

Ciyun Lin

2015-01-01

Full Text Available This paper aims at the traffic flow agglomeration effect characteristics and rapid evacuation requirement in sudden disaster; operation time of intraregional boundaries traffic signal coordination was presented firstly. Then intraregional boundaries intersection group dynamic subdivision and consolidation method based on relative similarity degree and similarity coefficient of adjacent intersections was put forward. As to make the traffic control strategy adapt to traffic condition of different intraregional boundaries intersection groups, this paper proposes an intraregional boundaries traffic signal coordination and optimization technology based on organic computing theory. Finally, this paper uses Delphi 7.0, MapX, and Oracle developing a software package, combined with Paramics V6 Simulator to validate the methods of this paper. The result shows that it can obviously improve disaster affected regional traffic signal control efficiency which reduces average traffic delay by 30–35%, decreases vehicle queue by more than 20% and reduces evacuation time more than 13.06%.