Software for energy modelling: a theoretical basis for improvements in the user interface
Energy Technology Data Exchange (ETDEWEB)
Siu, Y.L.
1989-09-01
A philosophical critique of the relationships between theory, knowledge and practice for a range of existing energy modelling styles is presented. In particular, Habermas's ideas are invoked regarding the three spheres of cognitive interest (i.e. technical, practical and emancipatory) and three levels of understanding of knowledge, the construction of an 'ideal speech situation', and the theory of communicative competence and action. These are adopted as a basis for revealing shortcomings of a representative selection of existing computer-based energy modelling styles, and as a springboard for constructing a new theoretical approach. (author).
The phantom derivative method when a structure model is available: about its theoretical basis.
Burla, Maria Cristina; Cascarano, Giovanni Luca; Giacovazzo, Carmelo; Polidori, Giampiero
2017-05-01
This study clarifies why, in the phantom derivative (PhD) approach, randomly created structures can help in refining phases obtained by other methods. For this purpose the joint probability distribution of target, model, ancil and phantom derivative structure factors and its conditional distributions have been studied. Since PhD may use n phantom derivatives, with n ≥ 1, a more general distribution taking into account all the ancil and derivative structure factors has been considered, from which the conditional distribution of the target phase has been derived. The corresponding conclusive formula contains two components. The first is the classical Srinivasan & Ramachandran term, relating the phases of the target structure with the model phases. The second arises from the combination of two correlations: that between model and derivative (the first is a component of the second) and that between derivative and target. The second component mathematically codifies the information on the target phase arising from model and derivative electron-density maps. The result is new, and explains why a random structure, uncorrelated with the target structure, adds useful information on the target phases, provided a model structure is known. Some experimental tests aimed at checking if the second component really provides information on ϕ (the target phase) were performed; the favourable results confirm the correctness of the theoretical calculations and of the corresponding analysis.
Directory of Open Access Journals (Sweden)
Pitts Nigel
2003-12-01
Full Text Available Abstract Background Biomedical research constantly produces new findings but these are not routinely translated into health care practice. One way to address this problem is to develop effective interventions to translate research findings into practice. Currently a range of empirical interventions are available and systematic reviews of these have demonstrated that there is no single best intervention. This evidence base is difficult to use in routine settings because it cannot identify which intervention is most likely to be effective (or cost effective in a particular situation. We need to establish a scientific rationale for interventions. As clinical practice is a form of human behaviour, theories of human behaviour that have proved useful in other similar settings may provide a basis for developing a scientific rationale for the choice of interventions to translate research findings into clinical practice. The objectives of the study are: to amplify and populate scientifically validated theories of behaviour with evidence from the experience of health professionals; to use this as a basis for developing predictive questionnaires using replicable methods; to identify which elements of the questionnaire (i.e., which theoretical constructs predict clinical practice and distinguish between evidence compliant and non-compliant practice; and on the basis of these results, to identify variables (based on theoretical constructs that might be prime targets for behaviour change interventions. Methods We will develop postal questionnaires measuring two motivational, three action and one stage theory to explore five behaviours with 800 general medical and 600 general dental practitioners. We will collect data on performance for each of the behaviours. The relationships between predictor variables (theoretical constructs and outcome measures (data on performance in each survey will be assessed using multiple regression analysis and structural equation
Sensemaking in Expatriation—A Theoretical Basis
Glanz, Lyn; Williams, Roger; Hoeksema, Ludwig
2001-01-01
Contemporary thinking and research into expatriation has fallen into two clusters: a macrostrategic level and a micropractice level. Some theoretical tension exists between the clusters, and calls for the reframing of understanding gained from the theoretical basis of past acculturation studies to
Theoretical basis for graphite stress analysis in BERSAFE
International Nuclear Information System (INIS)
Harper, P.G.
1980-03-01
The BERSAFE finite element computer program for structural analysis has been extended to deal with structures made from irradiated graphite. This report describes the material behaviour which has been modelled and gives the theoretical basis for the solution procedure. (author)
Theoretical basis of the new particles
International Nuclear Information System (INIS)
Rujula, A.
1977-01-01
The four-quark standard gauge field theory of weak, electromagnetic and strong interactions is reviewed and placed into a historical perspective since as early as 1961. Theoretical predictions of the model are compared to experimental observations available as of the Conference date, charm production in e + e - annihilation being in the spotlight. Virtues and shortcomings of the standard model are discussed. The model is concluded to have been an incredibly successful predictive tool. Some theoretical developments around the standard model are also discussed in view of CP violation in SU(2)xU(1) gauge theories, the Higgs' bosons and superunification of weak, strong and electromagnetic interactions
Social enterprise: theoretical basis and perespectives
Directory of Open Access Journals (Sweden)
Julian Narlev
2017-07-01
Full Text Available Since the 1980s the issues of social enterprises have gained particular popularity, practical and applied, as well as scientific significance. For a short period of time - almost half a century - social enterprises have become an integral part of education and academic research; they have turned into factors affecting noticeably the social and economic policy. The formation and development of social enterprises are the consequence of the profound social, demographic, cultural, global and public changes - the result of capitalism and its cornerstone, the enterprise. This contemporary and innovative theory is a natural extension of the strategies for change in societies and the world - both globally, and in response to the non-profit, public and business sectors - in an attempt to solve the topical and important issues of the time. In view of the circumstances given above, the present study aims to study and analyse - in the theoretical plan basis aspects of social enterprises, and on that to draw and systematize their perspectives for development.
Theoretical Basis Of The Company Competitiveness Assessment
Directory of Open Access Journals (Sweden)
Vladimir Nikiforovich Belkin
2015-03-01
Full Text Available The article deals with the basic theoretical questions of the company competitiveness assessment. The state of modern economic thought on this issue is shown. The main factors of the company competitiveness are specified. A specific role of staff of an enterprise is revealed: on the one hand, it is a resource, on the other is a subject, resulting in productive movement all factors of competitiveness, i.e. the staff is a critical factor in the company competitiveness. The criterion of company competitiveness is proposed, on its basis, the concept of “competitive enterprise” is defined. The most well-known approaches for assessing the company competitiveness are analyzed. The author’s method of the company competitiveness assessment based on the dynamics of the integral index of competitiveness is provided. For those cases, when it is impossible to determine the proportion of products on the market, it is proposed to evaluate the company competitiveness on the profitability of its production. The article shows the experience in calculating of the company competitiveness on the proposed author’s methods.
Ei, Shin-ichiro; Koiso, Miyuki; Ochiai, Hiroyuki; Okada, Kanzo; Saito, Shingo; Shirai, Tomoyuki
2014-01-01
This book deals with one of the most novel advances in mathematical modeling for applied scientific technology, including computer graphics, public-key encryption, data visualization, statistical data analysis, symbolic calculation, encryption, error correcting codes, and risk management. It also shows that mathematics can be used to solve problems from nature, e.g., slime mold algorithms. One of the unique features of this book is that it shows readers how to use pure and applied mathematics, especially those mathematical theory/techniques developed in the twentieth century, and developing now, to solve applied problems in several fields of industry. Each chapter includes clues on how to use "mathematics" to solve concrete problems faced in industry as well as practical applications. The target audience is not limited to researchers working in applied mathematics and includes those in engineering, material sciences, economics, and life sciences.
Directory of Open Access Journals (Sweden)
Pierre Tchakoua
2015-09-01
Full Text Available Models are crucial in the engineering design process because they can be used for both the optimization of design parameters and the prediction of performance. Thus, models can significantly reduce design, development and optimization costs. This paper proposes a novel equivalent electrical model for Darrieus-type vertical axis wind turbines (DTVAWTs. The proposed model was built from the mechanical description given by the Paraschivoiu double-multiple streamtube model and is based on the analogy between mechanical and electrical circuits. This work addresses the physical concepts and theoretical formulations underpinning the development of the model. After highlighting the working principle of the DTVAWT, the step-by-step development of the model is presented. For assessment purposes, simulations of aerodynamic characteristics and those of corresponding electrical components are performed and compared.
The Algorithm Theoretical Basis Document for Tidal Corrections
Fricker, Helen A.; Ridgway, Jeff R.; Minster, Jean-Bernard; Yi, Donghui; Bentley, Charles R.`
2012-01-01
This Algorithm Theoretical Basis Document deals with the tidal corrections that need to be applied to range measurements made by the Geoscience Laser Altimeter System (GLAS). These corrections result from the action of ocean tides and Earth tides which lead to deviations from an equilibrium surface. Since the effect of tides is dependent of the time of measurement, it is necessary to remove the instantaneous tide components when processing altimeter data, so that all measurements are made to the equilibrium surface. The three main tide components to consider are the ocean tide, the solid-earth tide and the ocean loading tide. There are also long period ocean tides and the pole tide. The approximate magnitudes of these components are illustrated in Table 1, together with estimates of their uncertainties (i.e. the residual error after correction). All of these components are important for GLAS measurements over the ice sheets since centimeter-level accuracy for surface elevation change detection is required. The effect of each tidal component is to be removed by approximating their magnitude using tidal prediction models. Conversely, assimilation of GLAS measurements into tidal models will help to improve them, especially at high latitudes.
Karimi, Leila; Ghassemi, Abbas
2016-07-01
Among the different technologies developed for desalination, the electrodialysis/electrodialysis reversal (ED/EDR) process is one of the most promising for treating brackish water with low salinity when there is high risk of scaling. Multiple researchers have investigated ED/EDR to optimize the process, determine the effects of operating parameters, and develop theoretical/empirical models. Previously published empirical/theoretical models have evaluated the effect of the hydraulic conditions of the ED/EDR on the limiting current density using dimensionless numbers. The reason for previous studies' emphasis on limiting current density is twofold: 1) to maximize ion removal, most ED/EDR systems are operated close to limiting current conditions if there is not a scaling potential in the concentrate chamber due to a high concentration of less-soluble salts; and 2) for modeling the ED/EDR system with dimensionless numbers, it is more accurate and convenient to use limiting current density, where the boundary layer's characteristics are known at constant electrical conditions. To improve knowledge of ED/EDR systems, ED/EDR models should be also developed for the Ohmic region, where operation reduces energy consumption, facilitates targeted ion removal, and prolongs membrane life compared to limiting current conditions. In this paper, theoretical/empirical models were developed for ED/EDR performance in a wide range of operating conditions. The presented ion removal and selectivity models were developed for the removal of monovalent ions and divalent ions utilizing the dominant dimensionless numbers obtained from laboratory scale electrodialysis experiments. At any system scale, these models can predict ED/EDR performance in terms of monovalent and divalent ion removal. Copyright © 2016 Elsevier Ltd. All rights reserved.
A Theoretical Basis for Adult Learning Facilitation: Review of ...
African Journals Online (AJOL)
The paper has reviewed six journal articles with topics ranging from theory of andragogy; the effect of globalization on adult learning; the contribution of Malcom Knowles; constructivism as a theoretical model for adult learning and the relevance of Piaget and neo-Piagetian theories on adult education. Each article was first ...
Bowen, Barbara Lynn
This study presents a holistic framework which can be used as a basis for decision-making at various points in the curriculum-instruction development process as described by Johnson in a work published in 1967. The proposed framework has conceptual bases in the work of Thomas S. Kuhn and David P. Ausubel and utilizes the work of several perceptual…
Theoretical basis of quantification for layer of protection analysis (LOPA)
International Nuclear Information System (INIS)
Jin, Jianghong; Shuai, Bing; Wang, Xiaodong; Zhu, Zuogang
2016-01-01
Highlights: • When there is an IPL and λ 0 ⩾ 1, λ(t) and λ 0 don’t have logarithm linear relation any more. • The equations of scenario frequency of the low and high demand mode are different. • As long as an initiating event contributes more than 50% to the overall frequency, maximum is better than summation. • There are shared IPLs of initial events, so maximum is better than summation. • The bigger dependence degree of initial event is, the better maximum method is. - Abstract: In order to guide the corrective application of LOPA, this paper tries to discuss the theoretical basis of quantification for LOPA by comparing the computing methods of event tree consequences. It also discusses the computing equations for scenario frequency of the high demand mode by taking the scenario frequency of an initial event with one independent layer of protection (IPL) as example. Based on the probability theory, the computing method for scenario frequency of multiple initial events is improved and the application principle of two methods, i.e. summation and maximum value are brought forth. Research results show that the scenario frequency of the low demand mode has a specific computing equation. But for the high demand mode, the IPLs should be analyzed one by one, and the computing equation should be selected according to the demand mode of an IPL. As long as a single initiating event contributes more than 50% to the overall frequency of a particular consequence or the accident scenario induced by each initial event has the shared IPL, maximum value method is appropriate; otherwise, summation method should be adopted.
THEORETICAL BASIS OF PARAMETRIC SYNTHESIS FOR CARRYING SYSTEMS OF CARS
Directory of Open Access Journals (Sweden)
O. V. Fomin
2017-08-01
Full Text Available Purpose. The article is aimed to systematize and structure representation of theoretical grounds for the optimization designing of railway car components and practical ways of its implementation. Methodology. The study is based on analysis of several well-known articles on the subject, as well as on authors' researches, some mathematical foundations and computer modeling. The rolling stock components structural analysis was made by applying modern and acknowledged methods. Findings. In the study the authors systematized the set of methodological approaches to the freight car design processes; they also analyzed every application phase of the designing process and its conditions. The article presents the developed mathematical model of the car component implementation. This model takes into account all the calculated cases of the car life cycle. Moreover, the model also can be applied to other transport modes accounting their specific operation modes. The possibility to generate different construction options for equally strong car component with minimum material intensity was also shown in the article. There were several methods developed for finding optimal solutions that make it possible to calculate the sought characteristics of construction elements with the reliable accuracy. The presented variety of different approaches significantly extends engineering apparatus by increasing the synthesis and analysis abilities of the car design. Originality. The authors proposed the methodological foundations of the car components design aimed at creating their optimal structural parameter execution and the operating features based on the results of the detailed research. Practical value. Expediency and effectiveness of the presented methods has been confirmed by positive experience of its application when constructing the general-purpose gondola cars, models 12-9904 and 12-9904-01, as well as when upgrading existing constructions of freight cars, model
Franchise Business Model: Theoretical Insights
Levickaitė, Rasa; Reimeris, Ramojus
2010-01-01
The article is based on literature review, theoretical insights, and deals with the topic of franchise business model. The objective of the paper is to analyse peculiarities of franchise business model and its developing conditions in Lithuania. The aim of the paper is to make an overview on franchise business model and its environment in Lithuanian business context. The overview is based on international and local theoretical insights. In terms of practical meaning, this article should be re...
Developing a theoretical basis for interpreting multisonde neutron logging
Energy Technology Data Exchange (ETDEWEB)
Polyachenko, A.L.; Shaposhnikova, T.A.
1979-01-01
The authors examine the current status of the theoretical development of multisonde neutron logging (MNK) and address the following problems in the area of MNK interpretation: 1) the formation of a multigroup, final-differential set program to calculate direct problems in the empirical curve relationships of MNK; 2) the physical nature of transfer and distribution of neutrons in a well-strata system (utilizing a simplified analytical theory); 3) the selection of the type of thermal and non-thermal neutron particles to be recorded by gamma radiation capture (which is based on a comparative analysis of total and partial error in determining the water content of strata utilizing each of these MNK modifications); 4) developing a system of calculative departure curves for both reinforced and non-reinforced oil and gas wells; 5) the construction of MNK diagrams for final strata thickness; 6) an approximation of analytical-numerical solutions to inverse MNK problems based on an analogaous inverse INNK (impulsed neutron-neutron logging) solutions; 7) an appraisal of the MNK method and associated theories for optimizing instruments and determining the limits to the information provided by this method. The need to continue research in the above areas 1, 4, 6, and 7 is underscored. Such research should be conducted on a three-dimensional rapid-acting calculation algorithm based on physical modeling.
International Nuclear Information System (INIS)
Knigavko, V.G.; Pilipenko, M.Yi.
1993-01-01
The work is devoted to theoretical basis of determining physiologically essential values of liver, kidneys, central and cerebral hemodynamics functional state according to the results of dynamic studies, New stochastic models of radiopharmaceuticals (RP) kinetics in the organism systems, new schemes to obtain primary information during the investigation as well as subsequent or simultaneous injection of two testing RP with different characteristics and similar or different labels was used
Theoretical models for supernovae
International Nuclear Information System (INIS)
Woosley, S.E.; Weaver, T.A.
1981-01-01
The results of recent numerical simulations of supernova explosions are presented and a variety of topics discussed. Particular emphasis is given to (i) the nucleosynthesis expected from intermediate mass (10sub solar less than or equal to M less than or equal to 100 Msub solar) Type II supernovae and detonating white dwarf models for Type I supernovae, (ii) a realistic estimate of the γ-line fluxes expected from this nucleosynthesis, (iii) the continued evolution, in one and two dimensions, of intermediate mass stars wherein iron core collapse does not lead to a strong, mass-ejecting shock wave, and (iv) the evolution and explosion of vary massive stars M greater than or equal to 100 Msub solar of both Population I and III. In one dimension, nuclear burning following a failed core bounce does not appear likely to lead to a supernova explosion although, in two dimensions, a combination of rotation and nuclear burning may do so. Near solar proportions of elements from neon to calcium and very brilliant optical displays may be created by hypernovae, the explosions of stars in the mass range 100 M/sub solar/ to 300 M/sub solar/. Above approx. 300 M/sub solar/ a black hole is created by stellar collapse following carbon ignition. Still more massive stars may be copious producers of 4 He and 14 N prior to their collapse on the pair instability
A Theoretic Basis for IS? The Contribution of ANT
Directory of Open Access Journals (Sweden)
Jim Underwood
2002-11-01
Full Text Available Representation is a key issue of IS design and operation that is often ignored. Actor-network theory (ANT, a semiotic theory of stakeholders, provides a way of dealing with representation. Combining aspects of ANT and Foucault's discourse theory allows us to include concepts as actors and promises a flexible and durable foundation for IS practice, but ANT itself indicates that the search for a purely theoretical foundation for IS is misguided.
Moral (or ethical) education in Slovakia and its theoretical basis
Gluchman Vasil
2016-01-01
With regard to existing concept of the moral education (ethics) in Slovakia, the questions of ethics and morals are only one of the partial sections. The dominant role is played by psychology based on Roberto Olivar’s concept with emphasis on pro-socialization and on Erickson’s concept of the psychosocial development. From the philosophy basis point of view, only Aristotle, even in reduced form and Spranger’s concept of the life forms are mentioned. Philosophy and ethics are only complements ...
The Quantum Cheshire Cat effect: Theoretical basis and observational implications
Duprey, Q.; Kanjilal, S.; Sinha, U.; Home, D.; Matzkin, A.
2018-04-01
The Quantum Cheshire Cat (QCC) is an effect introduced recently within the Weak Measurements framework. The main feature of the QCC effect is that a property of a quantum particle appears to be spatially separated from its position. The status of this effect has however remained unclear, as claims of experimental observation of the QCC have been disputed by strong criticism of the experimental as well as the theoretical aspects of the effect. In this paper we clarify in what precise sense the QCC can be regarded as an unambiguous consequence of the standard quantum mechanical formalism applied to describe quantum pointers weakly coupled to a system. In light of this clarification, the raised criticisms of the QCC effect are rebutted. We further point out that the limitations of the experiments performed to date imply that a loophole-free experimental demonstration of the QCC has not yet been achieved.
Moral (or ethical education in Slovakia and its theoretical basis
Directory of Open Access Journals (Sweden)
Gluchman Vasil
2016-06-01
Full Text Available With regard to existing concept of the moral education (ethics in Slovakia, the questions of ethics and morals are only one of the partial sections. The dominant role is played by psychology based on Roberto Olivar’s concept with emphasis on pro-socialization and on Erickson’s concept of the psychosocial development. From the philosophy basis point of view, only Aristotle, even in reduced form and Spranger’s concept of the life forms are mentioned. Philosophy and ethics are only complements to more psychologically based educational program which is resulting from the problematic division of a social and moral experience into egoistic and prosocial. Egoism is presented in a distorted form and is characterized as the cause of all moral evil. However, there are several different types of understanding of the term egoism in philosophy and ethics as for example psychological and ethical egoism, or self-interest. Ethical egoism or self-interest cannot be identified with selfishness. The main aim of moral education should not be only to form the desired children and youth moral orientation but on the other hand, to form morally self-confident individuals who are able to solve the moral problems, to help the others to solve them as well and to be able to bear moral responsibility for their own deeds.
Theoretical basis for convective invigoration due to increased aerosol concentration
Directory of Open Access Journals (Sweden)
Z. J. Lebo
2011-06-01
Full Text Available The potential effects of increased aerosol loading on the development of deep convective clouds and resulting precipitation amounts are studied by employing the Weather Research and Forecasting (WRF model as a detailed high-resolution cloud resolving model (CRM with both detailed bulk and bin microphysics schemes. Both models include a physically-based activation scheme that incorporates a size-resolved aerosol population. We demonstrate that the aerosol-induced effect is controlled by the balance between latent heating and the increase in condensed water aloft, each having opposing effects on buoyancy. It is also shown that under polluted conditions, increases in the CCN number concentration reduce the cumulative precipitation due to the competition between the sedimentation and evaporation/sublimation timescales. The effect of an increase in the IN number concentration on the dynamics of deep convective clouds is small and the resulting decrease in domain-averaged cumulative precipitation is shown not to be statistically significant, but may act to suppress precipitation. It is also shown that even in the presence of a decrease in the domain-averaged cumulative precipitation, an increase in the precipitation variance, or in other words, andincrease in rainfall intensity, may be expected in more polluted environments, especially in moist environments.
A significant difference exists between the predictions based on the bin and bulk microphysics schemes of precipitation and the influence of aerosol perturbations on updraft velocity within the convective core. The bulk microphysics scheme shows little change in the latent heating rates due to an increase in the CCN number concentration, while the bin microphysics scheme demonstrates significant increases in the latent heating aloft with increasing CCN number concentration. This suggests that even a detailed two-bulk microphysics scheme, coupled to a detailed activation scheme, may not be
Pediatric Physical Therapy: Part I. Practice Scope, Scientific Basis, and Theoretical Foundation.
Heriza, Carolyn B.; Sweeney, Jane K.
1994-01-01
This article on pediatric physical therapy first offers a historical perspective and then looks at the scope of clinical practice in the field, the field's scientific basis, and its theoretical foundations. (Author/DB)
Grassi, Alba; Mariño, Marcos
2015-02-01
Some matrix models admit, on top of the usual 't Hooft expansion, an M-theory-like expansion, i.e. an expansion at large N but where the rest of the parameters are fixed, instead of scaling with N . These models, which we call M-theoretic matrix models, appear in the localization of Chern-Simons-matter theories, and also in two-dimensional statistical physics. Generically, their partition function receives non-perturbative corrections which are not captured by the 't Hooft expansion. In this paper, we discuss general aspects of these type of matrix integrals and we analyze in detail two different examples. The first one is the matrix model computing the partition function of supersymmetric Yang-Mills theory in three dimensions with one adjoint hypermultiplet and N f fundamentals, which has a conjectured M-theory dual, and which we call the N f matrix model. The second one, which we call the polymer matrix model, computes form factors of the 2d Ising model and is related to the physics of 2d polymers. In both cases we determine their exact planar limit. In the N f matrix model, the planar free energy reproduces the expected behavior of the M-theory dual. We also study their M-theory expansion by using Fermi gas techniques, and we find non-perturbative corrections to the 't Hooft expansion.
Theoretical models of DNA flexibility
Czech Academy of Sciences Publication Activity Database
Dršata, Tomáš; Lankaš, Filip
2013-01-01
Roč. 3, č. 4 (2013), s. 355-363 ISSN 1759-0876 Institutional support: RVO:61388963 Keywords : molecular dynamics simulations * base pair level * indirect readout Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 9.041, year: 2013
Parameters and error of a theoretical model
International Nuclear Information System (INIS)
Moeller, P.; Nix, J.R.; Swiatecki, W.
1986-09-01
We propose a definition for the error of a theoretical model of the type whose parameters are determined from adjustment to experimental data. By applying a standard statistical method, the maximum-likelihoodlmethod, we derive expressions for both the parameters of the theoretical model and its error. We investigate the derived equations by solving them for simulated experimental and theoretical quantities generated by use of random number generators. 2 refs., 4 tabs
A theoretical basis for maintenance spinal manipulative therapy for the chiropractic profession
Taylor, David N.
2011-01-01
Object The purpose of this article is to discuss a theoretical basis for wellness chiropractic manipulative care and to develop a hypothesis for further investigation. Methods A search of PubMed and of the Manual, Alternative, and Natural Therapy Index System was performed with a combination of key words: chiropractic, maintenance and wellness care, maintenance manipulative care, preventive spinal manipulation, hypomobility, immobility, adhesions, joint degeneration, and neuronal degeneration...
Theoretical Models for Orthogonal Cutting
DEFF Research Database (Denmark)
De Chiffre, Leonardo
This review of simple models for orthogonal cutting was extracted from: “L. De Chiffre: Metal Cutting Mechanics and Applications, D.Sc. Thesis, Technical University of Denmark, 1990.”......This review of simple models for orthogonal cutting was extracted from: “L. De Chiffre: Metal Cutting Mechanics and Applications, D.Sc. Thesis, Technical University of Denmark, 1990.”...
BASIS: an internet resource for network modelling
Directory of Open Access Journals (Sweden)
Gillespie Colin S.
2006-12-01
Full Text Available There is a growing realisation that complex biological processes cannot be understood through the application of ever more reductionist experimental programs alone. Recognising this, we have a constructed a flexible web-service based modelling system called BASIS (Biology of Ageing e-Science Integration and Simulation, which facilitates model construction and development. In particular it allows users to store, share and simulate their models. The system is accessed through web-services using any language (e.g. Python or Java or under any operating system (e.g. Linux or Windows.
Managing Enterprise Innovation Development on the Basis of Controlling: Theoretical Aspect
Directory of Open Access Journals (Sweden)
Alyoshyn Serhiy Yu.
2014-01-01
Full Text Available The article reveals theoretical aspects of management of enterprise innovation development on the basis of controlling as an integrated system of information and analytical support of decision making processes. Such an approach supplements and establishes logical connections between basic categories and special notions, which allows clarification of the essence of the “management of enterprise innovation development on the basis of controlling” notion. The article draws a conclusion that controlling is an information and functional system, oriented at solution of enterprise innovation development tasks through application of modern management concepts, in particular, system of planning, analysis, accounting and control for achieving the synergy effect from their purposeful functioning and making efficient strategic and operative decisions with the aim of ensuring realisation of the set goals.
The Associative Basis of Scientific Creativity: A Model Proposal
Directory of Open Access Journals (Sweden)
Esra Kanli
2014-06-01
Full Text Available Creativity is accepted as an important part of scientific skills. Scientific creativity proceeds from a need or urge to solve a problem, and in-volves the production of original and useful ideas or products. Existing scientific creativity theories and tests do not feature the very im-portant thinking processes, such as analogical and associative thinking, which can be consid-ered crucial in creative scientific problem solv-ing. Current study’s aim is to provide an alter-native model and explicate the associative basis of scientific creativity. Emerging from the re-viewed theoretical framework, Scientific Asso-ciations Model is proposed. This model claims that, similarity and mediation constitutes the basis of creativity and focuses on three compo-nents namely; associative thinking, analogical thinking (analogical reasoning & analogical problem solving and insight which are consid-ered to be main elements of scientific associa-tive thinking.
Determination of cognitive development: postnonclassical theoretical model
Directory of Open Access Journals (Sweden)
Irina N. Pogozhina
2015-09-01
Full Text Available The aim of this research is to develop a postnonclassical cognitive processes content determination model in which mental processes are considered as open selfdeveloping, self-organizing systems. Three types of systems (dynamic, statistical, developing were analysed and compared on the basis of the description of the external and internal characteristics of causation, types of causal chains (dependent, independent and their interactions, as well as the nature of the relationship between the elements of the system (hard, probabilistic, mixed. Mechanisms of open non-equilibrium nonlinear systems (dissipative and four dissipative structures emergence conditions are described. Determination models of mental and behaviour formation and development that were developed under various theoretical approaches (associationism, behaviorism, gestaltism, psychology of intelligence by Piaget, Vygotsky culture historical approach, activity approach and others are mapped on each other as the models that describe behaviour of the three system types mentioned above. The development models of the mental sphere are shown to be different by the following criteria: 1 allocated determinants amount; 2 presence or absence of the system own activity that results in selecting the model not only external, but also internal determinants; 3 types of causal chains (dependent-independent-blended; 4 types of relationships between the causal chain that ultimately determines the subsequent system determination type as decisive (a tough dynamic pattern or stochastic (statistical regularity. The continuity of postnonclassical, classical and non-classical models of mental development determination are described. The process of gradual refinement, complexity, «absorption» of the mental determination by the latter models is characterized. The human mental can be deemed as the functioning of the open developing non-equilibrium nonlinear system (dissipative. The mental sphere is
A Set Theoretical Approach to Maturity Models
DEFF Research Database (Denmark)
Lasrado, Lester; Vatrapu, Ravi; Andersen, Kim Normann
2016-01-01
of it application on a social media maturity data-set. Specifically, we employ Necessary Condition Analysis (NCA) to identify maturity stage boundaries as necessary conditions and Qualitative Comparative Analysis (QCA) to arrive at multiple configurations that can be equally effective in progressing to higher......Maturity Model research in IS has been criticized for the lack of theoretical grounding, methodological rigor, empirical validations, and ignorance of multiple and non-linear paths to maturity. To address these criticisms, this paper proposes a novel set-theoretical approach to maturity models...... characterized by equifinality, multiple conjunctural causation, and case diversity. We prescribe methodological guidelines consisting of a six-step procedure to systematically apply set theoretic methods to conceptualize, develop, and empirically derive maturity models and provide a demonstration...
Modeling scientific: some theoretical and methodological considerations
Directory of Open Access Journals (Sweden)
Carlos Tamayo-Roca
2017-04-01
Full Text Available At present widespread use of models as an auxiliary system to penetrate the essence of phenomena related to all areas of cognitive and transforming activity of man, covering as diverse as human sciences fields. In the field of education use it is becoming more common as essential to transform school practice and enrich their theoretical instrument bitter day. The paper deals with the development of theoretical modeling as a scientific method to advance the process to be transformed and characterized by establishing relationships and links between the structural components that comprise it. In this regard it is proposed as an objective socialize some theoretical and methodological considerations that favor the use of modeling method in the scientific research activity of teachers.
Information-Theoretic Perspectives on Geophysical Models
Nearing, Grey
2016-04-01
practice of science (except by Gong et al., 2013, whose fundamental insight is the basis for this talk), and here I offer two examples of practical methods that scientists might use to approximately measure ontological information. I place this practical discussion in the context of several recent and high-profile experiments that have found that simple out-of-sample statistical models typically (vastly) outperform our most sophisticated terrestrial hydrology models. I offer some perspective on several open questions about how to use these findings to improve our models and understanding of these systems. Cartwright, N. (1983) How the Laws of Physics Lie. New York, NY: Cambridge Univ Press. Clark, M. P., Kavetski, D. and Fenicia, F. (2011) 'Pursuing the method of multiple working hypotheses for hydrological modeling', Water Resources Research, 47(9). Cover, T. M. and Thomas, J. A. (1991) Elements of Information Theory. New York, NY: Wiley-Interscience. Cox, R. T. (1946) 'Probability, frequency and reasonable expectation', American Journal of Physics, 14, pp. 1-13. Csiszár, I. (1972) 'A Class of Measures of Informativity of Observation Channels', Periodica Mathematica Hungarica, 2(1), pp. 191-213. Davies, P. C. W. (1990) 'Why is the physical world so comprehensible', Complexity, entropy and the physics of information, pp. 61-70. Gong, W., Gupta, H. V., Yang, D., Sricharan, K. and Hero, A. O. (2013) 'Estimating Epistemic & Aleatory Uncertainties During Hydrologic Modeling: An Information Theoretic Approach', Water Resources Research, 49(4), pp. 2253-2273. Jaynes, E. T. (2003) Probability Theory: The Logic of Science. New York, NY: Cambridge University Press. Nearing, G. S. and Gupta, H. V. (2015) 'The quantity and quality of information in hydrologic models', Water Resources Research, 51(1), pp. 524-538. Popper, K. R. (2002) The Logic of Scientific Discovery. New York: Routledge. Van Horn, K. S. (2003) 'Constructing a logic of plausible inference: a guide to cox's theorem
Theoretical models for recombination in expanding gas
International Nuclear Information System (INIS)
Avron, Y.; Kahane, S.
1978-09-01
In laser isotope separation of atomic uranium, one is confronted with the theoretical problem of estimating the concentration of thermally ionized uranium atoms. To investigate this problem theoretical models for recombination in an expanding gas and in the absence of local thermal equilibrium have been constructed. The expansion of the gas is described by soluble models of the hydrodynamic equation, and the recombination by rate equations. General results for the freezing effect for the suitable ranges of the gas parameters are obtained. The impossibility of thermal equilibrium in expanding two-component systems is proven
Modeling business processes: theoretical and practical aspects
Directory of Open Access Journals (Sweden)
V.V. Dubininа
2015-06-01
Full Text Available The essence of process-oriented enterprise management has been examined in the article. The content and types of information technology have been analyzed in the article, due to the complexity and differentiation of existing methods, as well as the specificity of language, terminology of the enterprise business processes modeling. The theoretical aspects of business processes modeling have been reviewed and the modern traditional modeling techniques received practical application in the visualization model of retailers activity have been studied in the article. In the process of theoretical analysis of the modeling methods found that UFO-toolkit method that has been developed by Ukrainian scientists due to it systemology integrated opportunities, is the most suitable for structural and object analysis of retailers business processes. It was designed visualized simulation model of the business process "sales" as is" of retailers using a combination UFO-elements with the aim of the further practical formalization and optimization of a given business process.
Theoretical study on optical model potential
International Nuclear Information System (INIS)
Lim Hung Gi.
1984-08-01
The optical model potential of non-local effect on the rounded edge of the potential is derived. On the basis of this potential the functional form of the optical model potential, the energy dependence and relationship of its parameters, and the dependency of the values of the parameters on energy change are shown in this paper. (author)
DEFF Research Database (Denmark)
Mørcke, Anne Mette; Dornan, Tim; Eika, Berit
2013-01-01
Outcome based or competency based education (OBE) is so firmly established in undergraduate medical education that it might not seem necessary to ask why it was included in recommendations for the future, like the Flexner centenary report. Uncritical acceptance may not, however, deliver its...... greatest benefits. Our aim was to explore the underpinnings of OBE: its historical origins, theoretical basis, and empirical evidence of its effects in order to answer the question: How can predetermined learning outcomes influence undergraduate medical education? This literature review had three...... components: A review of historical landmarks in the evolution of OBE; a review of conceptual frameworks and theories; and a systematic review of empirical publications from 1999 to 2010 that reported data concerning the effects of learning outcomes on undergraduate medical education. OBE had its origins...
Estimation of leaf area index and its sunlit portion from DSCOVR EPIC data: Theoretical basis.
Yang, Bin; Knyazikhin, Yuri; Mõttus, Matti; Rautiainen, Miina; Stenberg, Pauline; Yan, Lei; Chen, Chi; Yan, Kai; Choi, Sungho; Park, Taejin; Myneni, Ranga B
2017-09-01
This paper presents the theoretical basis of the algorithm designed for the generation of leaf area index and diurnal course of its sunlit portion from NASA's Earth Polychromatic Imaging Camera (EPIC) onboard NOAA's Deep Space Climate Observatory (DSCOVR). The Look-up-Table (LUT) approach implemented in the MODIS operational LAI/FPAR algorithm is adopted. The LUT, which is the heart of the approach, has been significantly modified. First, its parameterization incorporates the canopy hot spot phenomenon and recent advances in the theory of canopy spectral invariants. This allows more accurate decoupling of the structural and radiometric components of the measured Bidirectional Reflectance Factor (BRF), improves scaling properties of the LUT and consequently simplifies adjustments of the algorithm for data spatial resolution and spectral band compositions. Second, the stochastic radiative transfer equations are used to generate the LUT for all biome types. The equations naturally account for radiative effects of the three-dimensional canopy structure on the BRF and allow for an accurate discrimination between sunlit and shaded leaf areas. Third, the LUT entries are measurable, i.e., they can be independently derived from both below canopy measurements of the transmitted and above canopy measurements of reflected radiation fields. This feature makes possible direct validation of the LUT, facilitates identification of its deficiencies and development of refinements. Analyses of field data on canopy structure and leaf optics collected at 18 sites in the Hyytiälä forest in southern boreal zone in Finland and hyperspectral images acquired by the EO-1 Hyperion sensor support the theoretical basis.
A theoretical basis for maintenance spinal manipulative therapy for the chiropractic profession.
Taylor, David N
2011-12-01
The purpose of this article is to discuss a theoretical basis for wellness chiropractic manipulative care and to develop a hypothesis for further investigation. A SEARCH OF PUBMED AND OF THE MANUAL, ALTERNATIVE, AND NATURAL THERAPY INDEX SYSTEM WAS PERFORMED WITH A COMBINATION OF KEY WORDS: chiropractic, maintenance and wellness care, maintenance manipulative care, preventive spinal manipulation, hypomobility, immobility, adhesions, joint degeneration, and neuronal degeneration. Articles were collected, and trends were identified. The search revealed surveys of doctors and patients, an initial clinical pilot study, randomized control trials, and laboratory studies that provided correlative information to provide a framework for development of a hypothesis for the basis of maintenance spinal manipulative therapy. Maintenance care optimizes the levels of function and provides a process of achieving the best possible health. It is proposed that this may be accomplished by including chiropractic manipulative therapy in addition to exercise therapy, diet and nutritional counseling, and lifestyle coaching. It is hypothesized that because spinal manipulative therapy brings a joint to the end of the paraphysiological joint space to encourage normal range of motion, routine manipulation of asymptomatic patients may retard the progression of joint degeneration, neuronal changes, changes in muscular strength, and recruitment patterns, which may result in improved function, decreased episodes of injuries, and improved sense of well-being.
A theoretical model of multielectrode DBR lasers
DEFF Research Database (Denmark)
Pan, Xing; Olesen, Henning; Tromborg, Bjarne
1988-01-01
A theoretical model for two- and three-section tunable distributed Bragg reflector (DBR) lasers is presented. The static tuning properties are studied in terms of threshold current, linewidth, oscillation frequency, and output power. Regions of continuous tuning for three-section DBR lasers...
Hybrid quantum teleportation: A theoretical model
Energy Technology Data Exchange (ETDEWEB)
Takeda, Shuntaro; Mizuta, Takahiro; Fuwa, Maria; Yoshikawa, Jun-ichi; Yonezawa, Hidehiro; Furusawa, Akira [Department of Applied Physics, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan)
2014-12-04
Hybrid quantum teleportation – continuous-variable teleportation of qubits – is a promising approach for deterministically teleporting photonic qubits. We propose how to implement it with current technology. Our theoretical model shows that faithful qubit transfer can be achieved for this teleportation by choosing an optimal gain for the teleporter’s classical channel.
A field theoretic model for static friction
Mahyaeh, I.; Rouhani, S.
2013-01-01
We present a field theoretic model for friction, where the friction coefficient between two surfaces may be calculated based on elastic properties of the surfaces. We assume that the geometry of contact surface is not unusual. We verify Amonton's laws to hold that friction force is proportional to the normal load.This model gives the opportunity to calculate the static coefficient of friction for a few cases, and show that it is in agreement with observed values. Furthermore we show that the ...
Zepf, S; Hartmann, S
2001-01-01
The authors discuss the attempt by v. Uexküll and Wesiack to formulate the basics of human medicine within the framework of a sign theory. They criticize this attempt mainly in three points: 1. Central concepts of their model--i.e. "meaning", "sign" or "signcoupling"--are only used as general concepts and not in the differentiated manner they are conventionally used in semiotics. 2. Human behavior is reduced to conditioned reflex systems which are merely described in a different, semiotic way. 3. Problems evolving from the epistemology of a radical constructivism on which their model of a "bio-psycho-social medicine" is based, remain not only unsolved but also undiscussed.
Modelling in Accounting. Theoretical and Practical Dimensions
Directory of Open Access Journals (Sweden)
Teresa Szot -Gabryś
2010-10-01
Full Text Available Accounting in the theoretical approach is a scientific discipline based on specific paradigms. In the practical aspect, accounting manifests itself through the introduction of a system for measurement of economic quantities which operates in a particular business entity. A characteristic of accounting is its flexibility and ability of adaptation to information needs of information recipients. One of the main currents in the development of accounting theory and practice is to cover by economic measurements areas which have not been hitherto covered by any accounting system (it applies, for example, to small businesses, agricultural farms, human capital, which requires the development of an appropriate theoretical and practical model. The article illustrates the issue of modelling in accounting based on the example of an accounting model developed for small businesses, i.e. economic entities which are not obliged by law to keep accounting records.
PARFUME Theory and Model basis Report
Energy Technology Data Exchange (ETDEWEB)
Darrell L. Knudson; Gregory K Miller; G.K. Miller; D.A. Petti; J.T. Maki; D.L. Knudson
2009-09-01
The success of gas reactors depends upon the safety and quality of the coated particle fuel. The fuel performance modeling code PARFUME simulates the mechanical, thermal and physico-chemical behavior of fuel particles during irradiation. This report documents the theory and material properties behind vari¬ous capabilities of the code, which include: 1) various options for calculating CO production and fission product gas release, 2) an analytical solution for stresses in the coating layers that accounts for irradiation-induced creep and swelling of the pyrocarbon layers, 3) a thermal model that calculates a time-dependent temperature profile through a pebble bed sphere or a prismatic block core, as well as through the layers of each analyzed particle, 4) simulation of multi-dimensional particle behavior associated with cracking in the IPyC layer, partial debonding of the IPyC from the SiC, particle asphericity, and kernel migration (or amoeba effect), 5) two independent methods for determining particle failure probabilities, 6) a model for calculating release-to-birth (R/B) ratios of gaseous fission products that accounts for particle failures and uranium contamination in the fuel matrix, and 7) the evaluation of an accident condition, where a particle experiences a sudden change in temperature following a period of normal irradiation. The accident condi¬tion entails diffusion of fission products through the particle coating layers and through the fuel matrix to the coolant boundary. This document represents the initial version of the PARFUME Theory and Model Basis Report. More detailed descriptions will be provided in future revisions.
Theoretical models of neutron emission in fission
International Nuclear Information System (INIS)
Madland, D.G.
1992-01-01
A brief survey of theoretical representations of two of the observables in neutron emission in fission is given, namely, the prompt fission neutron spectrum N(E) and the average prompt neutron multiplicity bar v p . Early representations of the two observables are presented and their deficiencies are discussed. This is followed by summaries and examples of recent theoretical models for the calculation of these quantities. Emphasis is placed upon the predictability and accuracy of the new models. In particular, the dependencies of N(E) and bar v p upon the fissioning nucleus and its excitation energy are treated. Recent work in the calculation of the prompt fission neutron spectrum matrix N(E,E n ), where E n is the energy of the neutron inducing fission, is then discussed. Concluding remarks address the current status of our ability to calculate these observables with confidence, the direction of future theoretical efforts, and limititations to current and future calculations. Finally, recommendations are presented as to which model should be used currently and which model should be pursued in future efforts
Theoretical aspects of spatial-temporal modeling
Matsui, Tomoko
2015-01-01
This book provides a modern introductory tutorial on specialized theoretical aspects of spatial and temporal modeling. The areas covered involve a range of topics which reflect the diversity of this domain of research across a number of quantitative disciplines. For instance, the first chapter provides up-to-date coverage of particle association measures that underpin the theoretical properties of recently developed random set methods in space and time otherwise known as the class of probability hypothesis density framework (PHD filters). The second chapter gives an overview of recent advances in Monte Carlo methods for Bayesian filtering in high-dimensional spaces. In particular, the chapter explains how one may extend classical sequential Monte Carlo methods for filtering and static inference problems to high dimensions and big-data applications. The third chapter presents an overview of generalized families of processes that extend the class of Gaussian process models to heavy-tailed families known as alph...
The conceptual basis for interprofessional collaboration: core concepts and theoretical frameworks.
D'Amour, Danielle; Ferrada-Videla, Marcela; San Martin Rodriguez, Leticia; Beaulieu, Marie-Dominique
2005-05-01
Interprofessional collaboration is a key factor in initiatives designed to increase the effectiveness of health services currently offered to the public. It is important that the concept of collaboration be well understood, because although the increasingly complex health problems faced by health professionals are creating more interdependencies among them, we still have limited knowledge of the complexity of interprofessional relationships. The goal of this literature review was to identify conceptual frameworks that could improve our understanding of this important aspect of health organizations. To this end, we have identified and taken into consideration: (A) the various definitions proposed in the literature and the various concepts associated with collaboration, and (B) the various theoretical frameworks of collaboration. Our results demonstrate that: (1) the concept of collaboration is commonly defined through five underlying concepts: sharing, partnership, power, interdependency and process; (2) the most complete models of collaboration seem to be those based on a strong theoretical background, either in organizational theory or in organizational sociology and on empirical data; (3) there is a significant amount of diversity in the way the various authors conceptualized collaboration and in the factors influencing collaboration; (4) these frameworks do not establish clear links between the elements in the models and the outputs; and (5) the literature does not provide a serious attempt to determine how patients could be integrated into the health care team, despite the fact that patients are recognized as the ultimate justification for providing collaborative care.
Integrating IS and HCI Using Activity Theory as a Philosophical and Theoretical Basis
Directory of Open Access Journals (Sweden)
Helen Hasan
1999-05-01
Full Text Available The fields of Information Systems (IS and Human Computer Interaction (HCI are both multidisciplinary in nature and each is searching for an identity as a legitimate discipline in its own right, with a firm theoretical basis. Activity Theory offers a set of concepts, structures and terms which are eminently suited to both fields. It has its origins in the cultural historical psychology of Russia, and avoids the dichotomies between thought and action, and between individuals and society, that are prevalent in western thinking. This paper describes the basic principles of Activity Theory as they apply to IS and HCI, with particular emphasis on those systems which provide knowledge about the progress of their organisation to senior managers. Activity Theory principles will be used in a longitudinal case study to analyse an extensive project which attempted, with limited success, to produce management support systems in an organisation. The Activity Theory analysis indicates that an integrated IS and HCI approach would have improved the outcomes of this project.
Morcke, Anne Mette; Dornan, Tim; Eika, Berit
2013-10-01
Outcome based or competency based education (OBE) is so firmly established in undergraduate medical education that it might not seem necessary to ask why it was included in recommendations for the future, like the Flexner centenary report. Uncritical acceptance may not, however, deliver its greatest benefits. Our aim was to explore the underpinnings of OBE: its historical origins, theoretical basis, and empirical evidence of its effects in order to answer the question: How can predetermined learning outcomes influence undergraduate medical education? This literature review had three components: A review of historical landmarks in the evolution of OBE; a review of conceptual frameworks and theories; and a systematic review of empirical publications from 1999 to 2010 that reported data concerning the effects of learning outcomes on undergraduate medical education. OBE had its origins in behaviourist theories of learning. It is tightly linked to the assessment and regulation of proficiency, but less clearly linked to teaching and learning activities. Over time, there have been cycles of advocacy for, then criticism of, OBE. A recurring critique concerns the place of complex personal and professional attributes as "competencies". OBE has been adopted by consensus in the face of weak empirical evidence. OBE, which has been advocated for over 50 years, can contribute usefully to defining requisite knowledge and skills, and blueprinting assessments. Its applicability to more complex aspects of clinical performance is not clear. OBE, we conclude, provides a valuable approach to some, but not all, important aspects of undergraduate medical education.
Empathy and child neglect: a theoretical model.
De Paul, Joaquín; Guibert, María
2008-11-01
To present an explanatory theory-based model of child neglect. This model does not address neglectful behaviors of parents with mental retardation, alcohol or drug abuse, or severe mental health problems. In this model parental behavior aimed to satisfy a child's need is considered a helping behavior and, as a consequence, child neglect is considered as a specific type of non-helping behavior. The central hypothesis of the theoretical model presented here suggests that neglectful parents cannot develop the helping response set to care for their children because the observation of a child's signal of need does not lead to the experience of emotions that motivate helping or because the parents experience these emotions, but specific cognitions modify the motivation to help. The present theoretical model suggests that different typologies of neglectful parents could be developed based on different reasons that parents might not to experience emotions that motivate helping behaviors. The model can be helpful to promote new empirical studies about the etiology of different groups of neglectful families.
Surface physics theoretical models and experimental methods
Mamonova, Marina V; Prudnikova, I A
2016-01-01
The demands of production, such as thin films in microelectronics, rely on consideration of factors influencing the interaction of dissimilar materials that make contact with their surfaces. Bond formation between surface layers of dissimilar condensed solids-termed adhesion-depends on the nature of the contacting bodies. Thus, it is necessary to determine the characteristics of adhesion interaction of different materials from both applied and fundamental perspectives of surface phenomena. Given the difficulty in obtaining reliable experimental values of the adhesion strength of coatings, the theoretical approach to determining adhesion characteristics becomes more important. Surface Physics: Theoretical Models and Experimental Methods presents straightforward and efficient approaches and methods developed by the authors that enable the calculation of surface and adhesion characteristics for a wide range of materials: metals, alloys, semiconductors, and complex compounds. The authors compare results from the ...
A Theoretical Model of Water and Trade
Dang, Q.; Konar, M.; Reimer, J.; Di Baldassarre, G.; Lin, X.; Zeng, R.
2015-12-01
Water is an essential factor of agricultural production. Agriculture, in turn, is globalized through the trade of food commodities. In this paper, we develop a theoretical model of a small open economy that explicitly incorporates water resources. The model emphasizes three tradeoffs involving water decision-making that are important yet not always considered within the existing literature. One tradeoff focuses on competition for water among different sectors when there is a shock to one of the sectors only, such as trade liberalization and consequent higher demand for the product. A second tradeoff concerns the possibility that there may or may not be substitutes for water, such as increased use of sophisticated irrigation technology as a means to increase crop output in the absence of higher water availability. A third tradeoff explores the possibility that the rest of the world can be a source of supply or demand for a country's water-using products. A number of propositions are proven. For example, while trade liberalization tends to increase water use, increased pressure on water supplies can be moderated by way of a tax that is derivable with observable economic phenomena. Another example is that increased riskiness of water availability tends to cause water users to use less water than would be the case under profit maximization. These theoretical model results generate hypotheses that can be tested empirically in future work.
A Game Theoretic Model of Thermonuclear Cyberwar
Energy Technology Data Exchange (ETDEWEB)
Soper, Braden C. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
2017-08-23
In this paper we propose a formal game theoretic model of thermonuclear cyberwar based on ideas found in [1] and [2]. Our intention is that such a game will act as a first step toward building more complete formal models of Cross-Domain Deterrence (CDD). We believe the proposed thermonuclear cyberwar game is an ideal place to start on such an endeavor because the game can be fashioned in a way that is closely related to the classical models of nuclear deterrence [4–6], but with obvious modifications that will help to elucidate the complexities introduced by a second domain. We start with the classical bimatrix nuclear deterrence game based on the game of chicken, but introduce uncertainty via a left-of-launch cyber capability that one or both players may possess.
Modeling Heliospheric Interface: Observational and Theoretical Challenges
Pogorelov, N.; Heerikhuisen, J.; Borovikov, S.; Zank, G.
2008-12-01
Observational data provided by Voyager 1 and Voyager 2 spacecraft ahead of the heliospheric termination shock (TS) and in the heliosheath require considerate reassessment of theoretical models of the solar wind (SW) interaction with the magnetized interstellar medium (LISM). Contemporary models, although sophisticated enough to take into account kinetic processes accompanying charge exchange between ions and atoms and address the coupling of the interstellar and interplanetary magnetic fields (ISMF and IMF) at the heliospheric interface, are still unable to analyze the effect of non-thermal pick-up ions (PUI's) in the heliosheath. The presence of PUI's undermines the assumption of a Maxwellian distribution of the SW ions. We discuss the ways to improve physical models in this respect. The TS asymmetry observed by Voyagers can be attributed to the combination of 3D, time- dependent behavior of the SW and by the action of the ISMF. It is clear, however, that the ISMF alone can account for the TS asymmetry of about 10 AU only if it is unexpectedly strong (greater than 4 microgauss). We analyze the consequences of such magnetic fields for the neutral hydrogen deflection in the inner heliosphere from its original direction in the unperturbed LISM. We also discuss the conditions for the 2-3 kHz radio emission, which is believed to be generated in the outer heliosheath beyond the heliopause, and analyze possible location of radio emission sources under the assumption of strong magnetic field. The quality of the physical model becomes crucial when we need to address modern observational and theoretical challenges. We compare the plasma, neutral particle, and magnetic field distributions obtained with our MHD-kinetic and 5-fluid models. The transport of neutral particles is treated kinetically in the former and by a multiple neutral-fluid approach in the latter. We also investigate the distribution of magnetic field in the inner heliosheath for large angles between the Sun
A theoretical model of water and trade
Dang, Qian; Konar, Megan; Reimer, Jeffrey J.; Di Baldassarre, Giuliano; Lin, Xiaowen; Zeng, Ruijie
2016-03-01
Water is an essential input for agricultural production. Agriculture, in turn, is globalized through the trade of agricultural commodities. In this paper, we develop a theoretical model that emphasizes four tradeoffs involving water-use decision-making that are important yet not always considered in a consistent framework. One tradeoff focuses on competition for water among different economic sectors. A second tradeoff examines the possibility that certain types of agricultural investments can offset water use. A third tradeoff explores the possibility that the rest of the world can be a source of supply or demand for a country's water-using commodities. The fourth tradeoff concerns how variability in water supplies influences farmer decision-making. We show conditions under which trade liberalization affect water use. Two policy scenarios to reduce water use are evaluated. First, we derive a target tax that reduces water use without offsetting the gains from trade liberalization, although important tradeoffs exist between economic performance and resource use. Second, we show how subsidization of water-saving technologies can allow producers to use less water without reducing agricultural production, making such subsidization an indirect means of influencing water use decision-making. Finally, we outline conditions under which riskiness of water availability affects water use. These theoretical model results generate hypotheses that can be tested empirically in future work.
From theoretical model to practical use:
DEFF Research Database (Denmark)
Bjørk, Ida Torunn; Lomborg, Kirsten; Nielsen, Carsten Munch
2013-01-01
that is enhanced when appropriate support is given by leaders in the involved facilities. Conclusion. Knowledge translation is a time-consuming and collaborative endeavour. On the basis of our experience we advocate the implementation and use of a conceptual framework for the entire process of knowledge...... involving both the creation and application of knowledge in several phases. The case presented in this paper is the translation of the Model of Practical Skill Performance into education and practice. Advantages and problems with the use of this model and its adaptation and tailoring to local contexts...... of the model and to tailor the implementation of knowledge to the users. Implications for nursing. This article illustrates the need for enduring collaboration between stakeholders to promote the process of knowledge translation. Translation of research knowledge into practice is a time-consuming process...
Theoretical models for Mars and their seismic properties
Okal, E. A.; Anderson, D. L.
1978-01-01
Theoretical seismic properties of the planet Mars are investigated on the basis of the various models which have been proposed for the internal composition of the planet. The latest interpretation of gravity-field data, assuming a lower value of the moment of inertia, would require a less dense mantle and a larger core than previous models. If Mars is chondritic in composition, the most reasonable models are an incompletely differentiated H-chondrite or a mixture of H-chondrites and carbonaceous chondrites. Seismic profiles, travel times, and free oscillation periods are computed for various models, with the aim of establishing which seismic data is crucial for deciding among the alternatives. A detailed discussion is given of the seismic properties which could - in principle - help answer the questions of whether Mars' core is liquid or solid and whether Mars has a partially molten asthenosphere in its upper mantle.
Application of a theoretical model to evaluate COPD disease management
2010-01-01
Background Disease management programmes are heterogeneous in nature and often lack a theoretical basis. An evaluation model has been developed in which theoretically driven inquiries link disease management interventions to outcomes. The aim of this study is to methodically evaluate the impact of a disease management programme for patients with chronic obstructive pulmonary disease (COPD) on process, intermediate and final outcomes of care in a general practice setting. Methods A quasi-experimental research was performed with 12-months follow-up of 189 COPD patients in primary care in the Netherlands. The programme included patient education, protocolised assessment and treatment of COPD, structural follow-up and coordination by practice nurses at 3, 6 and 12 months. Data on intermediate outcomes (knowledge, psychosocial mediators, self-efficacy and behaviour) and final outcomes (dyspnoea, quality of life, measured by the CRQ and CCQ, and patient experiences) were obtained from questionnaires and electronic registries. Results Implementation of the programme was associated with significant improvements in dyspnoea (p theory-driven model enhances the design and evaluation of disease management programmes aimed at improving health outcomes. This study supports the notion that a theoretical approach strengthens the evaluation designs of complex interventions. Moreover, it provides prudent evidence that the implementation of COPD disease management programmes can positively influence outcomes of care. PMID:20346135
Application of a theoretical model to evaluate COPD disease management
Directory of Open Access Journals (Sweden)
Asin Javier D
2010-03-01
Full Text Available Abstract Background Disease management programmes are heterogeneous in nature and often lack a theoretical basis. An evaluation model has been developed in which theoretically driven inquiries link disease management interventions to outcomes. The aim of this study is to methodically evaluate the impact of a disease management programme for patients with chronic obstructive pulmonary disease (COPD on process, intermediate and final outcomes of care in a general practice setting. Methods A quasi-experimental research was performed with 12-months follow-up of 189 COPD patients in primary care in the Netherlands. The programme included patient education, protocolised assessment and treatment of COPD, structural follow-up and coordination by practice nurses at 3, 6 and 12 months. Data on intermediate outcomes (knowledge, psychosocial mediators, self-efficacy and behaviour and final outcomes (dyspnoea, quality of life, measured by the CRQ and CCQ, and patient experiences were obtained from questionnaires and electronic registries. Results Implementation of the programme was associated with significant improvements in dyspnoea (p Conclusions The application of a theory-driven model enhances the design and evaluation of disease management programmes aimed at improving health outcomes. This study supports the notion that a theoretical approach strengthens the evaluation designs of complex interventions. Moreover, it provides prudent evidence that the implementation of COPD disease management programmes can positively influence outcomes of care.
Application of a theoretical model to evaluate COPD disease management.
Lemmens, Karin M M; Nieboer, Anna P; Rutten-Van Mölken, Maureen P M H; van Schayck, Constant P; Asin, Javier D; Dirven, Jos A M; Huijsman, Robbert
2010-03-26
Disease management programmes are heterogeneous in nature and often lack a theoretical basis. An evaluation model has been developed in which theoretically driven inquiries link disease management interventions to outcomes. The aim of this study is to methodically evaluate the impact of a disease management programme for patients with chronic obstructive pulmonary disease (COPD) on process, intermediate and final outcomes of care in a general practice setting. A quasi-experimental research was performed with 12-months follow-up of 189 COPD patients in primary care in the Netherlands. The programme included patient education, protocolised assessment and treatment of COPD, structural follow-up and coordination by practice nurses at 3, 6 and 12 months. Data on intermediate outcomes (knowledge, psychosocial mediators, self-efficacy and behaviour) and final outcomes (dyspnoea, quality of life, measured by the CRQ and CCQ, and patient experiences) were obtained from questionnaires and electronic registries. Implementation of the programme was associated with significant improvements in dyspnoea (p theory-driven model enhances the design and evaluation of disease management programmes aimed at improving health outcomes. This study supports the notion that a theoretical approach strengthens the evaluation designs of complex interventions. Moreover, it provides prudent evidence that the implementation of COPD disease management programmes can positively influence outcomes of care.
Painter, K J; Hunt, G S; Wells, K L; Johansson, J A; Headon, D J
2012-08-06
In his seminal 1952 paper, 'The Chemical Basis of Morphogenesis', Alan Turing lays down a milestone in the application of theoretical approaches to understand complex biological processes. His deceptively simple demonstration that a system of reacting and diffusing chemicals could, under certain conditions, generate spatial patterning out of homogeneity provided an elegant solution to the problem of how one of nature's most intricate events occurs: the emergence of structure and form in the developing embryo. The molecular revolution that has taken place during the six decades following this landmark publication has now placed this generation of theoreticians and biologists in an excellent position to rigorously test the theory and, encouragingly, a number of systems have emerged that appear to conform to some of Turing's fundamental ideas. In this paper, we describe the history and more recent integration between experiment and theory in one of the key models for understanding pattern formation: the emergence of feathers and hair in the skins of birds and mammals.
Images as a basis for computer modelling
Beaufils, D.; LeTouzé, J.-C.; Blondel, F.-M.
1994-03-01
New computer technologies such as the graphics data tablet, video digitization and numerical methods, can be used for measurement and mathematical modelling in physics. Two programs dealing with newtonian mechanics and some of related scientific activities for A-level students are described.
Theoretical postulation of PLC channel model
Directory of Open Access Journals (Sweden)
Alexandru Ionuţ Chiuţă
2009-05-01
Full Text Available The objective of this document is to supply atheoretical basis for modelling the communicationlinks over powerlines. A comprehensive summary oftransmission properties and the noise scenario onpublic mains supply when used for data transmissionare given.Different PLC models - PLC channel, noise inPLC channel, coupling units, filters and conditioningdevices – will be created and they will be used tosimulate the PLC channel.PLC applications will have to work at veryunusual channels, solely designed for optimalelectrical power transportation, completelydisregarding signal transmission at high frequencies.It is shown that the typical properties aredescribed by transfer functions and noise scenariostypical for access and inhouse networks. The generaltransfer function for different channel types is derivedand, since an emulation system should reproducetypical classes of channels rather than singlemeasurements, the transfer function is concretisedwith reference channels. These are later serving asbasis for development of channel simulators andchannel emulators. Special attention is paid tomodelling of aperiodic impulsive noise since PLCsystems are reacting very sensitive to them and thisclass of noise has been insufficiently considered so far.
Directory of Open Access Journals (Sweden)
Horbach Tatiana
2018-01-01
Full Text Available Introduction. The main goal of changing accounting systems in different countries today is improving the quality of accounting information and achieving a high level of user confidence in accounting (financial reporting. However, the diversity of user needs is not the main reason why the problem of improving the quality of accounting and reporting data remains relevant. Purpose. Development of separate provisions of the theory of accounting in terms of ensuring high quality of accounting (financial reporting and development of practical recommendations for the assessment of the quality of the process of formation of accounting (financial reporting. Results. The article discloses the features of informational content of accounting (financial reporting in modern conditions. The comprehensive model of accounting information specifies the substantive content of the concept, the methodical approach to the assessment of the quality of accounting (financial reporting, taking into account the peculiarities of the organizational design of the quality management process for reporting and the peculiarities of the operation of the accounting and analytical system of the enterprise. The main identified problem areas are the formation of qualitative accounting (financial reporting. It is shown that the qualitative characteristics of accounting information and accounting (financial reporting can not be only within the framework of the work of the accounting system, but also must be lead by a set of factors that determine the end-user characteristics of accounting information. Conclusions. The internal content and essence of the abstract category “quality” are considered in detail, and it is demonstrated, as in the concretization of the subject, the conceptual design “quality of accounting (financial reporting” can be introduced. On the basis of the studies of Ukrainian and foreign scholars, eight areas are identified, which identify the main issues of
International Nuclear Information System (INIS)
Carlsson, T.; Muurinen, A.
2008-12-01
This report reviews the state-of-the-art with regard to redox measurements, especially in compacted water saturated bentonite, but also in natural systems like sediments and ground waters. Both theoretical and practical aspects of redox measurements are discussed, as well as some basic concepts like terminal electron-accepting processes (TEAPs) and oxidative capacity (OXC). The problems associated with the interpretation of measured electrode potentials are treated. Despite many practical and theoretical difficulties, redox measurements continue to be carried out by researchers all over the world. The over-all conclusion from the literature survey is that fruitful redox-measurements can be performed in compacted bentonite. Irrespective of whether the measured redox potentials are absolute or not, the use of electrodes provide a valuable tool for studying, e.g., long-term changes in the pore water of compacted bentonite and/or the diffusion of oxygen into a bentonite. (orig.)
Mixed waste treatment model: Basis and analysis
International Nuclear Information System (INIS)
Palmer, B.A.
1995-09-01
The Department of Energy's Programmatic Environmental Impact Statement (PEIS) required treatment system capacities for risk and cost calculation. Los Alamos was tasked with providing these capacities to the PEIS team. This involved understanding the Department of Energy (DOE) Complex waste, making the necessary changes to correct for problems, categorizing the waste for treatment, and determining the treatment system requirements. The treatment system requirements depended on the incoming waste, which varied for each PEIS case. The treatment system requirements also depended on the type of treatment that was desired. Because different groups contributing to the PEIS needed specific types of results, we provided the treatment system requirements in a variety of forms. In total, some 40 data files were created for the TRU cases, and for the MLLW case, there were 105 separate data files. Each data file represents one treatment case consisting of the selected waste from various sites, a selected treatment system, and the reporting requirements for such a case. The treatment system requirements in their most basic form are the treatment process rates for unit operations in the desired treatment system, based on a 10-year working life and 20-year accumulation of the waste. These results were reported in cubic meters and for the MLLW case, in kilograms as well. The treatment system model consisted of unit operations that are linked together. Each unit operation's function depended on the input waste streams, waste matrix, and contaminants. Each unit operation outputs one or more waste streams whose matrix, contaminants, and volume/mass may have changed as a result of the treatment. These output streams are then routed to the appropriate unit operation for additional treatment until the output waste stream meets the treatment requirements for disposal. The total waste for each unit operation was calculated as well as the waste for each matrix treated by the unit
Directory of Open Access Journals (Sweden)
P S Sorokin
2012-03-01
Full Text Available The article discusses the main current approaches to the interpretation of the term professional career, as well as the established lines of empirical study of the factors of career development. The author points out to the insufficient co-ordination between the efforts of theoretical conceptualization of career-related issues and the empirical studies of this subject. The author analyzes the most promising directions for further career research in terms of Bourdieu's theory of social space. Primarily, the author focuses on elaborating the concepts of career field and career capital related to it.
Assessing a Theoretical Model on EFL College Students
Chang, Yu-Ping
2011-01-01
This study aimed to (1) integrate relevant language learning models and theories, (2) construct a theoretical model of college students' English learning performance, and (3) assess the model fit between empirically observed data and the theoretical model proposed by the researchers of this study. Subjects of this study were 1,129 Taiwanese EFL…
The basis function approach for modeling autocorrelation in ecological data.
Hefley, Trevor J; Broms, Kristin M; Brost, Brian M; Buderman, Frances E; Kay, Shannon L; Scharf, Henry R; Tipton, John R; Williams, Perry J; Hooten, Mevin B
2017-03-01
Analyzing ecological data often requires modeling the autocorrelation created by spatial and temporal processes. Many seemingly disparate statistical methods used to account for autocorrelation can be expressed as regression models that include basis functions. Basis functions also enable ecologists to modify a wide range of existing ecological models in order to account for autocorrelation, which can improve inference and predictive accuracy. Furthermore, understanding the properties of basis functions is essential for evaluating the fit of spatial or time-series models, detecting a hidden form of collinearity, and analyzing large data sets. We present important concepts and properties related to basis functions and illustrate several tools and techniques ecologists can use when modeling autocorrelation in ecological data. © 2016 by the Ecological Society of America.
Directory of Open Access Journals (Sweden)
Dr. Dave S. Knowlton
2002-07-01
Full Text Available Addressing Carsten and Worsfold's (2000 assertion that online learning eliminates the possibility for "liberal learning," the author of this paper describes the context and guidelines for an online discussion assignment that he used as a faculty member at a liberal arts college. The purpose of this assignment was to help students engage in personal development by examining the ways course content manifested itself in their own lives. After describing the assignment guidelines, the author connects the assignment to numerous theories that are often associated with "liberal arts" learning. This theoretical explication includes connections to the need for a synthesis between the personal and professional selves, notions of constructing knowledge, and online discussion's placement within the writing process. The implication of this article is that the instructional strategies embedded in an online discussion, not the online environment itself, sustains a liberal education.
Towards elimination of asbestos-related diseases: a theoretical basis for international cooperation.
Takahashi, Ken; Kang, Seong-Kyu
2010-12-01
We develop a theoretical framework for international cooperation that can be used for the elimination of asbestos-related diseases (ARDs). The framework is based on the similarities in the temporal patterns of asbestos use and occurrence of ARDs in diverse countries. The status of each nation can be characterized by observing asbestos use and ARD frequency therein using a time window. Countries that supply technology for prevention of ARDs can be classified as donors and countries that receive these technologies as recipients. We suggest identification of three levels of core preventative technologies. Development of a common platform to gather and manage core preventative technologies will combine the strengths of donor countries and the needs of recipient countries.
Explaining clinical behaviors using multiple theoretical models.
Eccles, Martin P; Grimshaw, Jeremy M; MacLennan, Graeme; Bonetti, Debbie; Glidewell, Liz; Pitts, Nigel B; Steen, Nick; Thomas, Ruth; Walker, Anne; Johnston, Marie
2012-10-17
In the field of implementation research, there is an increased interest in use of theory when designing implementation research studies involving behavior change. In 2003, we initiated a series of five studies to establish a scientific rationale for interventions to translate research findings into clinical practice by exploring the performance of a number of different, commonly used, overlapping behavioral theories and models. We reflect on the strengths and weaknesses of the methods, the performance of the theories, and consider where these methods sit alongside the range of methods for studying healthcare professional behavior change. These were five studies of the theory-based cognitions and clinical behaviors (taking dental radiographs, performing dental restorations, placing fissure sealants, managing upper respiratory tract infections without prescribing antibiotics, managing low back pain without ordering lumbar spine x-rays) of random samples of primary care dentists and physicians. Measures were derived for the explanatory theoretical constructs in the Theory of Planned Behavior (TPB), Social Cognitive Theory (SCT), and Illness Representations specified by the Common Sense Self Regulation Model (CSSRM). We constructed self-report measures of two constructs from Learning Theory (LT), a measure of Implementation Intentions (II), and the Precaution Adoption Process. We collected data on theory-based cognitions (explanatory measures) and two interim outcome measures (stated behavioral intention and simulated behavior) by postal questionnaire survey during the 12-month period to which objective measures of behavior (collected from routine administrative sources) were related. Planned analyses explored the predictive value of theories in explaining variance in intention, behavioral simulation and behavior. Response rates across the five surveys ranged from 21% to 48%; we achieved the target sample size for three of the five surveys. For the predictor variables
Explaining clinical behaviors using multiple theoretical models
Directory of Open Access Journals (Sweden)
Eccles Martin P
2012-10-01
Full Text Available Abstract Background In the field of implementation research, there is an increased interest in use of theory when designing implementation research studies involving behavior change. In 2003, we initiated a series of five studies to establish a scientific rationale for interventions to translate research findings into clinical practice by exploring the performance of a number of different, commonly used, overlapping behavioral theories and models. We reflect on the strengths and weaknesses of the methods, the performance of the theories, and consider where these methods sit alongside the range of methods for studying healthcare professional behavior change. Methods These were five studies of the theory-based cognitions and clinical behaviors (taking dental radiographs, performing dental restorations, placing fissure sealants, managing upper respiratory tract infections without prescribing antibiotics, managing low back pain without ordering lumbar spine x-rays of random samples of primary care dentists and physicians. Measures were derived for the explanatory theoretical constructs in the Theory of Planned Behavior (TPB, Social Cognitive Theory (SCT, and Illness Representations specified by the Common Sense Self Regulation Model (CSSRM. We constructed self-report measures of two constructs from Learning Theory (LT, a measure of Implementation Intentions (II, and the Precaution Adoption Process. We collected data on theory-based cognitions (explanatory measures and two interim outcome measures (stated behavioral intention and simulated behavior by postal questionnaire survey during the 12-month period to which objective measures of behavior (collected from routine administrative sources were related. Planned analyses explored the predictive value of theories in explaining variance in intention, behavioral simulation and behavior. Results Response rates across the five surveys ranged from 21% to 48%; we achieved the target sample size for three of
Scaling of mean inertia and theoretical basis for a log law in turbulent boundary layers
Philip, Jimmy; Morrill-Winter, Caleb; Klewicki, Joseph
2017-11-01
Log law in the mean streamwise velocity (U) for pipes/channels is well accepted based on the derivation from the mean momentum balance (MMB) equation and support from experimental data. For flat plate turbulent boundary layers (TBLs), however, there is only empirical evidence and a theoretical underpinning of the kind available for pipes/channels in lacking. The main difficultly is the mean inertia (MI) term in the MMB equation, which, unlike in pipes/channels, is not a constant in TBLs. We present results from our paper (JFM `` 2017, Vol 813, pp 594-617), where the MI term for TBL is transformed so as to render it invariant in the outer region, corroborated with high Re (δ+) data from Melbourne Wind Tunnel and New Hampshire Flow Physics Facility. The transformation is possible because the MI term in the TBL has a `shape' which becomes invariant with increasing δ+ and a `magnitude' which is proportional to 1 /δ+ . The transformed equation is then employed to derive a log law for U with κ an order one (von-Karman) constant. We also show that the log law begins at y+ =C1√{δ+} , and the peak location of the Reynolds shear stress, ym+ =C2√{δ+} , where, C1 3.6 and C2 2.17 are from high Re data. Australian Research Council and the US National Science Foundation.
Waniewski, J; Werynski, A; Ahrenholz, P; Lucjanek, P; Judycki, W; Esther, G
1991-04-01
Dialyzer clearance K is usually presented as K = K0 + Tr Qu, were Qu is ultrafiltration rate, K0 is clearance for Qu = 0, and Tr is transmittance coefficient. Although a simple and accurate mathematical description of K0 is widely used, only a somewhat inaccurate formula for Tr that predicts a linear relationship between Tr and K0 has been proposed before. In this study the detailed investigation of Tr using a one-dimensional theory of a dialyzer is presented. In general, the application of a one-dimensional theory requires sophisticated numerical methods, but for small and middle molecular weight solutes an analytical formula for K can be derived. Tr predicted by the developed theory in comparison to Tr predicted by the previous linear formula is higher for small molecular weight solutes and lower for middle and large molecular weight solutes. These theoretical results were confirmed in experiments carried out in vitro for hollow-fiber dialyzers and small molecular weight solutes (urea, creatinine, sodium, TcO4) as well as middle molecular weight solutes (vitamin B12).
Directory of Open Access Journals (Sweden)
Shpak Sergiy O.
2017-04-01
Full Text Available The article is aimed at developing an internally consistent system of formal strictly defined concepts of the theory of strategic management of industrial restructuring and substantiating, on this basis, appropriateness of an approach to strategic planning for restructuring, based on the monitoring and management of enterprise potentials. It has been shown that restructuring of the production sphere of industrial enterprise is a process of targeted changes in the structure of enterprise, affecting the material-technical supply, production, and marketing subsystems, which are generally managed at the strategic, tactical and operational levels. A comprehensive characterization of the current and future (of the possible structures of enterprise may be provided by its potentials. The conception of strategic management of enterprises restructuring based on the development of their potentials dictates certain requirements to the composition of tasks to be solved and the methodological tools used for this purpose, among them, priority should be given to the development of potentially promising enterprise structures and the choice of the most promising ones, as well as methods for assessment of potentials.
Modelling in Accounting. Theoretical and Practical Dimensions
Teresa Szot -Gabryś
2010-01-01
Accounting in the theoretical approach is a scientific discipline based on specific paradigms. In the practical aspect, accounting manifests itself through the introduction of a system for measurement of economic quantities which operates in a particular business entity. A characteristic of accounting is its flexibility and ability of adaptation to information needs of information recipients. One of the main currents in the development of accounting theory and practice is to cover by economic...
A review of the theoretical basis for bulk mass flux convective parameterization
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R. S. Plant
2010-04-01
Full Text Available Most parameterizations for precipitating convection in use today are bulk schemes, in which an ensemble of cumulus elements with different properties is modelled as a single, representative entraining-detraining plume. We review the underpinning mathematical model for such parameterizations, in particular by comparing it with spectral models in which elements are not combined into the representative plume. The chief merit of a bulk model is that the representative plume can be described by an equation set with the same structure as that which describes each element in a spectral model. The equivalence relies on an ansatz for detrained condensate introduced by Yanai et al. (1973 and on a simplified microphysics. There are also conceptual differences in the closure of bulk and spectral parameterizations. In particular, we show that the convective quasi-equilibrium closure of Arakawa and Schubert (1974 for spectral parameterizations cannot be carried over to a bulk parameterization in a straightforward way. Quasi-equilibrium of the cloud work function assumes a timescale separation between a slow forcing process and a rapid convective response. But, for the natural bulk analogue to the cloud-work function, the relevant forcing is characterised by a different timescale, and so its quasi-equilibrium entails a different physical constraint. Closures of bulk parameterizations that use a parcel value of CAPE do not suffer from this timescale issue. However, the Yanai et al. (1973 ansatz must be invoked as a necessary ingredient of those closures.
International Nuclear Information System (INIS)
Itoh, Makoto
2000-01-01
This paper discusses how and why a disaster caused by a bad reputation (Fu-Hyo) occurs in Japan. We survey several cases of reputational disasters and develop a simple model of the process of how a reputational disaster occurs, lasts, and vanishes. We also show the necessity of third parties or information volunteers to reduce the damage of a reputational disaster. (author)
Blalock, Susan J
2011-12-01
There is an urgent need for research to improve the quality of medication use among those who require pharmacotherapy. To describe how behavioral science theories can help to achieve this goal. We begin by describing what a theory is and the functions that theories serve. We then provide 8 guiding principles that are crucial for investigators to understand if they are to use theory appropriately. We conclude by discussing the need for a new model of patient medication self-management that incorporates information concerning factors operating at all levels of the ecological framework, ranging from patient-level to societal-level factors. The 8 guiding principles discussed are the following: (1) There is no single theory that is appropriate for guiding all medication use research; (2) Behavioral science theories are probabilistic, not deterministic; (3) When trying to influence a health behavior, the health behavior of interest must be defined precisely; (4) Many factors outside of patient control influence patient medication use; (5) Every patient is unique; (6) Patient motivation is a fundamental ingredient required to optimize medication use, especially when maintenance of long term behavior is the goal; (7) Health care providers can have a profound effect on patient medication use, and this effect can operate through several possible causal pathways; and (8) When planning an intervention to optimize medication use, it is important to develop a conceptual model that links intervention inputs to the ultimate outcomes that are desired. Medication use can be influenced by a wide variety of factors acting at different levels of the ecological model. The quality of research on medication use could be improved by development of an ecological model specific to medication self-management. Copyright © 2011 Elsevier Inc. All rights reserved.
Modeling of alkynes: synthesis and theoretical properties
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Renato Rosseto
2003-06-01
Full Text Available In this paper we present the synthesis and simulation of alkynes derivatives. Semiempirical calculations were carried out for the ground and first excited states, including the spectroscopic properties of the absorption and emission (fluorescence and phosphorescence spectra by INDO/S-CI and DNdM-INDO/S-CI methods with geometries fully optimized by PM3/CI. The fact that the theoretical spectra are in accord with the experimental absorption spectra gives us a new possible approach on how structure modifications could affect the non-linear optical properties of alkynes.
Theoretical basis of the DOE-2 building energy use analysis program
Curtis, R. B.
1981-04-01
A user-oriented, public domain, computer program was developed that will enable architects and engineers to perform design and retrofit studies of the energy-use of buildings under realistic weather conditions. The DOE-2.1A has been named by the US DOE as the standard evaluation technique for the Congressionally mandated building energy performance standards (BEPS). A number of program design decisions were made that determine the breadth of applicability of DOE-2.1. Such design decisions are intrinsic to all building energy use analysis computer programs and determine the types of buildings or the kind of HVAC systems that can be modeled. In particular, the weighting factor method used in DOE-2 has both advantages and disadvantages relative to other computer programs.
Algebraic Specifications, Higher-order Types and Set-theoretic Models
DEFF Research Database (Denmark)
Kirchner, Hélène; Mosses, Peter David
2001-01-01
, and power-sets. This paper presents a simple framework for algebraic specifications with higher-order types and set-theoretic models. It may be regarded as the basis for a Horn-clause approximation to the Z framework, and has the advantage of being amenable to prototyping and automated reasoning. Standard...
How faith heals: a theoretical model.
Levin, Jeff
2009-01-01
This paper summarizes theoretical perspectives from psychology supportive of a healing effect of faith. First, faith is defined as a congruence of belief, trust, and obedience in relation to God or the divine. Second, evidence for a faith-healing association is presented, empirically and in theory. To exemplify religiously sanctioned affirmation of such a connection, selected passages are cited from the Jewish canon attesting to biblical and rabbinic support for a faith factor in longevity, disease risk, mental health and well-being, disease prevention, and healing. Third, reference to theories of hope, learned optimism, positive illusions, and opening up or disclosure, and to theory and research on psychoneuroimmunology and placebos, demonstrates that contemporary psychology can accommodate a healing power of faith. This is summarized in a typology of five hypothesized mechanisms underlying a faith-healing association, termed behavioral/conative, interpersonal, cognitive, affective, and psychophysiological. Finally, implications are discussed for the rapprochement of religion and medicine.
POSITIVE LEADERSHIP MODELS: THEORETICAL FRAMEWORK AND RESEARCH
Directory of Open Access Journals (Sweden)
Javier Blanch, Francisco Gil
2016-09-01
Full Text Available The objective of this article is twofold; firstly, we establish the theoretical boundaries of positive leadership and the reasons for its emergence. It is related to the new paradigm of positive psychology that has recently been shaping the scope of organizational knowledge. This conceptual framework has triggered the development of the various forms of positive leadership (i.e. transformational, servant, spiritual, authentic, and positive. Although the construct does not seem univocally defined, these different types of leadership overlap and share a significant affinity. Secondly, we review the empirical evidence that shows the impact of positive leadership in organizations and we highlight the positive relationship between these forms of leadership and key positive organizational variables. Lastly, we analyse future research areas in order to further develop this concept.
Wright, Lauren; Simpson, William; Van Lieshout, Ryan J; Steiner, Meir
2014-04-01
Clinical studies have established an inherent comorbidity between depression and the development of cardiovascular disease (CVD). Furthermore, this comorbidity seems to be more amplified in women than in men. To further investigate this comorbidity, a thorough literature review was conducted on studies from 1992 to date. The PubMed database was accessed using the keywords: cardiovascular disease, inflammation, depression, and sex differences. Both human and animal studies were considered. This review takes the standpoint that depression and CVD are both inflammatory disorders, and that their co-occurrence may be related to how the hypothalamic-pituitary-adrenal axis, serotonergic transmission and circulation, and the renin-angiotensin-aldosterone system via angiotensin II are affected by the excess secretion of proinflammatory cytokines. More recently, preliminary research attributes this systemic inflammation to a global deficiency in CD4+CD25+FOXP3 regulatory T cells. 17-β estradiol and progesterone mediated modulation of cytokine secretion may partially explain the sex differences observed. These hormones and reproductive events associated with hormonal fluctuations are discussed in depth, including the analysis of perinatal models of depression and CVD, including preeclampsia. However, as evidenced by this review, there is a need for mechanistic research in humans to truly understand the nature and directionality of the relationship between depression and CVD.
K. Sridhar Moorthy's Theoretical Modelling in Marketing - A Review ...
African Journals Online (AJOL)
Modelling has become a visible tool in many disciplines including marketing and several marketing models have been constructed. These models serve their pedagogical and practical purposes in some cases. However, among the marketing models so often cited is Moorthy‟s Theoretical Modelling in Marketing.
Laguerre-Gauss basis functions in observer models
Burgess, Arthur E.
2003-05-01
Observer models based on linear classifiers with basis functions (channels) are useful for evaluation of detection performance with medical images. They allow spatial domain calculations with a covariance matrix of tractable size. The term "channelized Fisher-Hotelling observer" will be used here. It is also called the "channelized Hotelling observer" model. There are an infinite number of basis function (channel ) sets that could be employed. Examples of channel sets that have been used include: difference of Gaussian (DOG) filters, difference of Mesa (DOM) filters and Laguerre-Gauss (LG) basis functions. Another option, sums of LG functions (LGS), will also be presented here. This set has the advantage of having no DC response. The effect of the number of images used to estimate model observer performance will be described, for both filtered 1/f3 noise and GE digital mammogram backgrounds. Finite sample image sets introduce both bias and variance to the estimate. The results presented here agree with previous work on linear classifiers. The LGS basis set gives a small but statistically significant reduction in bias. However, this may not be of much practical benefit. Finally, the effect of varying the number of basis functions included in the set will be addressed. It was found that four LG bases or three LGS bases are adequate.
Hypermedia as an experiential learning tool: a theoretical model
Jose Miguel Baptista Nunes; Susan P. Fowell
1996-01-01
The process of methodical design and development is of extreme importance in the production of educational software. However, this process will only be effective, if it is based on a theoretical model that explicitly defines what educational approach is being used and how specific features of the technology can best support it. This paper proposes a theoretical model of how hypermedia can be used as an experiential learning tool. The development of the model was based on a experiential learni...
Theoretical Models of Neutrino Mixing Recent Developments
Altarelli, Guido
2009-01-01
The data on neutrino mixing are at present compatible with Tri-Bimaximal (TB) mixing. If one takes this indication seriously then the models that lead to TB mixing in first approximation are particularly interesting and A4 models are prominent in this list. However, the agreement of TB mixing with the data could still be an accident. We discuss a recent model based on S4 where Bimaximal mixing is instead valid at leading order and the large corrections needed to reproduce the data arise from the diagonalization of charged leptons. The value of $\\theta_{13}$ could distinguish between the two alternatives.
Theoretical Analysis of a Modified Continuum Model
Ge, Hong-Xia; Wu, Shu-Zhen; Cheng, Rong-Jun; Lo, Siu-ming
2011-09-01
Based on the optimal velocity (OV) model, a new car-following model for traffic flow with the consideration of the driver's forecast effect (DFE) was proposed by Tang et al., which can be used to describe some complex traffic phenomena better. Using an asymptotic approximation between the headway and density, we obtain a new macro continuum version of the car-following model with the DFE. The linear stability theory is applied to derive the neutral stability condition. The Korteweg—de Vries equation near the neutral stability line is given by nonlinear analysis and the corresponding solution for the traffic density wave is derived.
Dark energy observational evidence and theoretical models
Novosyadlyj, B; Shtanov, Yu; Zhuk, A
2013-01-01
The book elucidates the current state of the dark energy problem and presents the results of the authors, who work in this area. It describes the observational evidence for the existence of dark energy, the methods and results of constraining of its parameters, modeling of dark energy by scalar fields, the space-times with extra spatial dimensions, especially Kaluza---Klein models, the braneworld models with a single extra dimension as well as the problems of positive definition of gravitational energy in General Relativity, energy conditions and consequences of their violation in the presence of dark energy. This monograph is intended for science professionals, educators and graduate students, specializing in general relativity, cosmology, field theory and particle physics.
Theoretical modelling of carbon deposition processes
International Nuclear Information System (INIS)
Marsh, G.R.; Norfolk, D.J.; Skinner, R.F.
1985-01-01
Work based on capsule experiments in the BNL Gamma Facility, aimed at elucidating the chemistry involved in the formation of carbonaceous deposit on CAGR fuel pin surfaces is described. Using a data-base derived from capsule experiments together with literature values for the kinetics of the fundamental reactions, a chemical model of the gas-phase processes has been developed. This model successfully reproduces the capsule results, whilst preliminary application to the WAGR coolant circuit indicates the likely concentration profiles of various radical species within the fuel channels. (author)
SOME THEORETICAL MODELS EXPLAINING ADVERTISING EFFECTS
Directory of Open Access Journals (Sweden)
Vasilica Magdalena SOMEŞFĂLEAN
2014-06-01
Full Text Available Persuade clients is still the main focus of the companies, using a set of methods and techniques designed to influence their behavior, in order to obtain better results (profits over a longer period of time. Since the late nineteenth - early twentieth century, the american E.St.Elmo Lewis, considered a pioneer in advertising and sales, developed the first theory, AIDA model, later used by marketers and advertisers to develop a marketing communications strategy. Later studies have developed other models that are the main subject of this research, which explains how and why persuasive communication works, to understand why some approaches are effective and others are not.
Theoretical Modelling of Intercultural Communication Process
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Mariia Soter
2016-08-01
Full Text Available The definition of the concepts of “communication”, “intercultural communication”, “model of communication” are analyzed in the article. The basic components of the communication process are singled out. The model of intercultural communication is developed. Communicative, behavioral and complex skills for optimal organization of intercultural communication, establishment of productive contact with a foreign partner to achieve mutual understanding, searching for acceptable ways of organizing interaction and cooperation for both communicants are highlighted in the article. It is noted that intercultural communication through interaction between people affects the development of different cultures’ aspects.
Conceptual basis for developing of trainig models in complex ...
African Journals Online (AJOL)
This paper presents conceptual basis for developing of training models of interactive assembling system for automatic building of application software systems, obtained during practical works over "Design and architecture of software systems" and "Object-oriented analysis and design" courses. The system is intended for ...
K. Sridhar Moorthy's Theoretical Modelling in Marketing - A Review
African Journals Online (AJOL)
Toshiba
cases. However, among the marketing models so often cited is. Moorthy‟s Theoretical Modelling in Marketing. This model is important, and hence this review once more, in that it offers a starting point, and in some cases the finishing line, for those who want to tread the pedestrian of modelling in marketing. But this is not the ...
Basis expansion model for channel estimation in LTE-R communication system
Directory of Open Access Journals (Sweden)
Ling Deng
2016-05-01
Full Text Available This paper investigates fast time-varying channel estimation in LTE-R communication systems. The Basis Expansion Model (BEM is adopted to fit the fast time-varying channel in a high-speed railway communication scenario. The channel impulse response is modeled as the sum of basis functions multiplied by different coefficients. The optimal coefficients are obtained by theoretical analysis. Simulation results show that a Generalized Complex-Exponential BEM (GCE-BEM outperforms a Complex-Exponential BEM (CE-BEM and a polynomial BEM in terms of Mean Squared Error (MSE. Besides, the MSE of the CE-BEM decreases gradually as the number of basis functions increases. The GCE-BEM has a satisfactory performance with the serious fading channel.
K. Sridhar Moorthy's Theoretical Modelling in Marketing - A Review
African Journals Online (AJOL)
Toshiba
/afrrev.v8i1.15. K. Sridhar Moorthy's Theoretical Modelling in. Marketing - A Review. Okoye, Ikechukwu-Maria Nnamdi Hyacinth. Head, Micro Enterprise Development/Training. University of Nigeria Nsukka Centre for Entrepreneurship and.
SOME THEORETICAL MODELS EXPLAINING ADVERTISING EFFECTS
Vasilica Magdalena SOMEŞFĂLEAN
2014-01-01
Persuade clients is still the main focus of the companies, using a set of methods and techniques designed to influence their behavior, in order to obtain better results (profits) over a longer period of time. Since the late nineteenth - early twentieth century, the american E.St.Elmo Lewis, considered a pioneer in advertising and sales, developed the first theory, AIDA model, later used by marketers and advertisers to develop a marketing communications strategy. Later studies have developed o...
Explaining clinical behaviors using multiple theoretical models
Eccles, Martin P; Grimshaw, Jeremy M; MacLennan, Graeme; Bonetti, Debbie; Glidewell, Liz; Pitts, Nigel B; Steen, Nick; Thomas, Ruth; Walker, Anne; Johnston, Marie
2012-01-01
Abstract Background In the field of implementation research, there is an increased interest in use of theory when designing implementation research studies involving behavior change. In 2003, we initiated a series of five studies to establish a scientific rationale for interventions to translate research findings into clinical practice by exploring the performance of a number of different, commonly used, overlapping behavioral theories and models. We reflect on the strengths and weaknesses of...
Toward a theoretical model for mindfulness-based pain management.
Day, Melissa A; Jensen, Mark P; Ehde, Dawn M; Thorn, Beverly E
2014-07-01
Mindfulness, as both a process and a practice, has received substantial research attention across a range of health conditions, including chronic pain. Previously proposed mechanisms underlying the potential health-related benefits of mindfulness and mindfulness-based interventions (MBIs) are based on a strong theoretical background. However, to date, an empirically grounded, integrated theoretical model of the mechanisms of MBIs within the context of chronic pain has yet to be proposed. This is a surprising gap in the literature given the exponential growth of studies reporting on the benefits of MBIs for heterogeneous chronic pain conditions. Moreover, given the importance of determining how, and for whom, psychological interventions for pain management are effective, it is imperative that this gap in the literature be addressed. The overarching aim of the current theoretical paper was to propose an initial integrated, theoretically driven, and empirically based model of the mechanisms of MBIs for chronic pain management. Theoretical and research implications of the model are discussed. The theoretical considerations proposed herein can be used to help organize and guide future research that will identify the mechanisms underlying the benefits of mindfulness-based treatments, and perhaps psychosocial treatments more broadly, for chronic pain management. This focus article presents an initial framework for an empirically based, theoretical model of the mechanisms of MBIs for chronic pain management. Implications of the framework for refining theory and for future research are addressed. Copyright © 2014 American Pain Society. Published by Elsevier Inc. All rights reserved.
Category-theoretic models of linear Abadi & Plotkin Logic
DEFF Research Database (Denmark)
Birkedal, Lars; Møgelberg, Rasmus Ejlers; Lerchedahl Petersen, Rasmus
2008-01-01
This paper presents a sound and complete category-theoretic notion of models for Linear Abadi & Plotkin Logic [Birkedal et al., 2006], a logic suitable for reasoning about parametricity in combination with recursion. A subclass of these called parametric LAPL structures can be seen...... as an axiomatization of domain theoretic models of parametric polymorphism, and we show how to solve general (nested) recursive domain equations in these. parametric LAPL structures constitute a general notion of model of parametricity in a setting with recursion. In future papers we will demonstrate this by showing...... how many different models of parametricity and recursion give rise to parametric LAPL structures, including Simpson and Rosolini’s set theoretic models [Rosolini and Simpson, 2004], a syntactic model based on Lily [Pitts, 2000, Bierman et al., 2000] and a model based on admissible pers over...
Theoretical Modelling of Sound Radiation from Plate
Zaman, I.; Rozlan, S. A. M.; Yusoff, A.; Madlan, M. A.; Chan, S. W.
2017-01-01
Recently the development of aerospace, automotive and building industries demands the use of lightweight materials such as thin plates. However, the plates can possibly add to significant vibration and sound radiation, which eventually lead to increased noise in the community. So, in this study, the fundamental concept of sound pressure radiated from a simply-supported thin plate (SSP) was analyzed using the derivation of mathematical equations and numerical simulation of ANSYS®. The solution to mathematical equations of sound radiated from a SSP was visualized using MATLAB®. The responses of sound pressure level were measured at far field as well as near field in the frequency range of 0-200 Hz. Result shows that there are four resonance frequencies; 12 Hz, 60 Hz, 106 Hz and 158 Hz were identified which represented by the total number of the peaks in the frequency response function graph. The outcome also indicates that the mathematical derivation correlated well with the simulation model of ANSYS® in which the error found is less than 10%. It can be concluded that the obtained model is reliable and can be applied for further analysis such as to reduce noise emitted from a vibrating thin plate.
Oceanographic model and radiological basis for control of radionuclide releases
International Nuclear Information System (INIS)
Hagen, A.A.
1984-01-01
Since it first prepared the provisional Definition of high-level radioactive waste unsuitable for dumping at sea and Recommendations for those radioactive wastes dumped under special permit in 1974, the IAEA has kept the Definition and Recommendations under continuing review. The oceanographic basis for the definition is being re-evaluated, based on a 1983 Report from the IMO/FAO/UNESCO/WMO/WHO/IAEA/UN/UNEP Joint Group of Experts on the Scientific Aspects of Marine Pollution (GESAMP), and the radiological basis is being updated, based on a Report from an IAEA Advisory Group Meeting held in 1982. The differences in the current radiological and oceanographic bases and the updating of both the GESAMP Report on modelling and the review of the radiological basis are delineated. In addition, a discussion of the future course of the Agency's activities in this area is given. (author)
a Theoretical Model of a Superheated Liquid Droplet Neutron Detector.
Harper, Mark Joseph
Neutrons can interact with the atoms in superheated liquid droplets which are suspended in a viscous matrix material, resulting in the formation of charged recoil ions. These ions transfer energy to the liquid, sometimes resulting in the droplets vaporizing and producing observable bubbles. Devices employing this mechanism are known as superheated liquid droplet detectors, or bubble detectors. The basis of bubble detector operation is identical to that of bubble chambers, which have been well characterized by researchers such as Wilson, Glaser, Seitz, and others since the 1950's. Each of the microscopic superheated liquid droplets behaves like an independent bubble chamber. This dissertation presents a theoretical model which considers the three principal aspects of detector operation: nuclear reactions, charged particle energy deposition, and thermodynamic bubble formation. All possible nuclear reactions were examined and those which could reasonably result in recoil ions sufficiently energetic to vaporize a droplet were analyzed in detail. Feasible interactions having adequate cross sections include elastic and inelastic scattering, n-proton, and n-alpha reactions. Ziegler's TRansport of Ions in Matter (TRIM) code was used to calculate the ions' stopping powers in various compounds based on the ionic energies predicted by standard scattering distributions. If the ions deposit enough energy in a small enough volume then the entire droplet will vaporize without further energy input. Various theories as to the vaporization of droplets by ionizing radiation were studied and a novel method of predicting the critical (minimum) energy was developed. This method can be used to calculate the minimum required stopping power for the ion, from which the threshold neutron energy is obtainable. Experimental verification of the model was accomplished by measuring the response of two different types of bubble detectors to monoenergetic thermal neutrons, as well as to neutrons
Process modelling on a canonical basis[Process modelling; Canonical modelling
Energy Technology Data Exchange (ETDEWEB)
Siepmann, Volker
2006-12-20
Based on an equation oriented solving strategy, this thesis investigates a new approach to process modelling. Homogeneous thermodynamic state functions represent consistent mathematical models of thermodynamic properties. Such state functions of solely extensive canonical state variables are the basis of this work, as they are natural objective functions in optimisation nodes to calculate thermodynamic equilibrium regarding phase-interaction and chemical reactions. Analytical state function derivatives are utilised within the solution process as well as interpreted as physical properties. By this approach, only a limited range of imaginable process constraints are considered, namely linear balance equations of state variables. A second-order update of source contributions to these balance equations is obtained by an additional constitutive equation system. These equations are general dependent on state variables and first-order sensitivities, and cover therefore practically all potential process constraints. Symbolic computation technology efficiently provides sparsity and derivative information of active equations to avoid performance problems regarding robustness and computational effort. A benefit of detaching the constitutive equation system is that the structure of the main equation system remains unaffected by these constraints, and a priori information allows to implement an efficient solving strategy and a concise error diagnosis. A tailor-made linear algebra library handles the sparse recursive block structures efficiently. The optimisation principle for single modules of thermodynamic equilibrium is extended to host entire process models. State variables of different modules interact through balance equations, representing material flows from one module to the other. To account for reusability and encapsulation of process module details, modular process modelling is supported by a recursive module structure. The second-order solving algorithm makes it
Dynamics in Higher Education Politics: A Theoretical Model
Kauko, Jaakko
2013-01-01
This article presents a model for analysing dynamics in higher education politics (DHEP). Theoretically the model draws on the conceptual history of political contingency, agenda-setting theories and previous research on higher education dynamics. According to the model, socio-historical complexity can best be analysed along two dimensions: the…
Theoretical modelling of actinide spectra in solution
International Nuclear Information System (INIS)
Danilo, Cecile
2009-01-01
The framework of this PhD is the interpretation of Nuclear Magnetic Relaxation Dispersion experiments performed on solvated U 4+ , NpO 2 + and PuO 2 2+ , which all have a f 2 configuration. Unexpectedly the two actinyl ions have a much higher relaxivity than U 4+ ,. One possible explanation is that the electronic relaxation rate is faster for Uranium(IV) than for the actinyl ions. We address this problem by exploring the electronic spectrum of the three compounds in gas phase and in solution with a two-step SOCI (Spin-Orbit Configuration-Interaction) method. The influence of electron correlation (treated in the first step) and spin-orbit relaxation effects (considered in the second step) has been discussed thoroughly. Solvent effects have been investigated as well. Another issue that has been questioned is the accuracy of Density Functional Theory for the study of actinide species. This matter has been discussed by comparing its performance to wave-function based correlated methods. The chemical problem chosen was the water exchange in [UO 2 2+ (H 2 O) 5 ]. We looked at the associative and at the dissociative mechanisms using a model with one additional water in the second hydration sphere. The last part of the thesis dealt with the spectroscopy of coordinated Uranyl(V). Absorption spectrum of Uranyl(V) with various ligands has been recorded. The first sharp absorption bands in the Near-Infrared region were assigned to the Uranium centered 5f-5f transitions, but uncertainties remained for the assignment of transitions observed in the Visible region. We computed the spectra of naked UO 2 + and [UO 2 (CO 3 ) 3 ] 5- to elucidate the spectral changes induced by the carbonate ligands. (author) [fr
Modeling Marine Electromagnetic Survey with Radial Basis Function Networks
Directory of Open Access Journals (Sweden)
Agus Arif
2014-11-01
Full Text Available A marine electromagnetic survey is an engineering endeavour to discover the location and dimension of a hydrocarbon layer under an ocean floor. In this kind of survey, an array of electric and magnetic receivers are located on the sea floor and record the scattered, refracted and reflected electromagnetic wave, which has been transmitted by an electric dipole antenna towed by a vessel. The data recorded in receivers must be processed and further analysed to estimate the hydrocarbon location and dimension. To conduct those analyses successfuly, a radial basis function (RBF network could be employed to become a forward model of the input-output relationship of the data from a marine electromagnetic survey. This type of neural networks is working based on distances between its inputs and predetermined centres of some basis functions. A previous research had been conducted to model the same marine electromagnetic survey using another type of neural networks, which is a multi layer perceptron (MLP network. By comparing their validation and training performances (mean-squared errors and correlation coefficients, it is concluded that, in this case, the MLP network is comparatively better than the RBF network[1].[1] This manuscript is an extended version of our previous paper, entitled Radial Basis Function Networks for Modeling Marine Electromagnetic Survey, which had been presented on 2011 International Conference on Electrical Engineering and Informatics, 17-19 July 2011, Bandung, Indonesia.
Modeling theoretical uncertainties in phenomenological analyses for particle physics
Energy Technology Data Exchange (ETDEWEB)
Charles, Jerome [CNRS, Aix-Marseille Univ, Universite de Toulon, CPT UMR 7332, Marseille Cedex 9 (France); Descotes-Genon, Sebastien [CNRS, Univ. Paris-Sud, Universite Paris-Saclay, Laboratoire de Physique Theorique (UMR 8627), Orsay Cedex (France); Niess, Valentin [CNRS/IN2P3, UMR 6533, Laboratoire de Physique Corpusculaire, Aubiere Cedex (France); Silva, Luiz Vale [CNRS, Univ. Paris-Sud, Universite Paris-Saclay, Laboratoire de Physique Theorique (UMR 8627), Orsay Cedex (France); Univ. Paris-Sud, CNRS/IN2P3, Universite Paris-Saclay, Groupe de Physique Theorique, Institut de Physique Nucleaire, Orsay Cedex (France); J. Stefan Institute, Jamova 39, P. O. Box 3000, Ljubljana (Slovenia)
2017-04-15
The determination of the fundamental parameters of the Standard Model (and its extensions) is often limited by the presence of statistical and theoretical uncertainties. We present several models for the latter uncertainties (random, nuisance, external) in the frequentist framework, and we derive the corresponding p values. In the case of the nuisance approach where theoretical uncertainties are modeled as biases, we highlight the important, but arbitrary, issue of the range of variation chosen for the bias parameters. We introduce the concept of adaptive p value, which is obtained by adjusting the range of variation for the bias according to the significance considered, and which allows us to tackle metrology and exclusion tests with a single and well-defined unified tool, which exhibits interesting frequentist properties. We discuss how the determination of fundamental parameters is impacted by the model chosen for theoretical uncertainties, illustrating several issues with examples from quark flavor physics. (orig.)
A Simple theoretical model for 63Ni betavoltaic battery
International Nuclear Information System (INIS)
ZUO, Guoping; ZHOU, Jianliang; KE, Guotu
2013-01-01
A numerical simulation of the energy deposition distribution in semiconductors is performed for 63 Ni beta particles. Results show that the energy deposition distribution exhibits an approximate exponential decay law. A simple theoretical model is developed for 63 Ni betavoltaic battery based on the distribution characteristics. The correctness of the model is validated by two literature experiments. Results show that the theoretical short-circuit current agrees well with the experimental results, and the open-circuit voltage deviates from the experimental results in terms of the influence of the PN junction defects and the simplification of the source. The theoretical model can be applied to 63 Ni and 147 Pm betavoltaic batteries. - Highlights: • The energy deposition distribution is found following an approximate exponential decay law when beta particles emitted from 63 Ni pass through a semiconductor. • A simple theoretical model for 63 Ni betavoltaic battery is constructed based on the exponential decay law. • Theoretical model can be applied to the betavoltaic batteries which radioactive source has a similar energy spectrum with 63 Ni, such as 147 Pm
Test of theoretical models for ultrafast heterogeneous electron ...
Indian Academy of Sciences (India)
Administrator
with the predictions of different theoretical models for light-induced ultrafast heterogeneous electron transfer (HET). ... theory model based on molecular dynamics simulations for the vibrational modes were also considered. Based on the known vibrational .... Pseudo 3D map of a 2PPE measurement with. Pe' achored via the ...
Theoretical bases of modeling decision-marketing solutions
Grigoruk Pavel Mikhaylovych
2012-01-01
The paper deals with issues related with theoretical aspects of modelling of marketing decision making process. According to system approach marketing decision making process is seen as a set of related subprocesses. Provided an opportunity to use the economic and mathematical modelling at each stage of the decision making process.
Circumplex model of marital and family systems: VI. Theoretical update.
Olson, D H; Russell, C S; Sprenkle, D H
1983-03-01
This paper updates the theoretical work on the Circumplex Model and provides revised and new hypotheses. Similarities and contrasts to the Beavers Systems Model are made along with comments regarding Beavers and Voeller's critique. FACES II, a newly revised assessment tool, provides both "perceived" and "ideal" family assessment that is useful empirically and clinically.
A theoretical model for predicting neutron fluxes for cyclic Neutron ...
African Journals Online (AJOL)
A theoretical model has been developed for prediction of thermal neutron fluxes required for cyclic irradiations of a sample to obtain the same activity previously used for the detection of any radionuclide of interest. The model is suitable for radiotracer production or for long-lived neutron activation products where the ...
Culture and Developmental Trajectories: A Discussion on Contemporary Theoretical Models
de Carvalho, Rafael Vera Cruz; Seidl-de-Moura, Maria Lucia; Martins, Gabriela Dal Forno; Vieira, Mauro Luís
2014-01-01
This paper aims to describe, compare and discuss the theoretical models proposed by Patricia Greenfield, Çigdem Kagitçibasi and Heidi Keller. Their models have the common goal of understanding the developmental trajectories of self based on dimensions of autonomy and relatedness that are structured according to specific cultural and environmental…
Desublimation process: verification and applications of a theoretical model
International Nuclear Information System (INIS)
Eby, R.S.
1979-01-01
A theoretical model simulating the simultaneous heat and mass transfer which takes place during the desublimation of a gas to a solid is presented. Desublimer column loading profiles to experimentally verify the model were obtained using a gamma scintillation technique. The data indicate that, if the physical parameters of the desublimed frost material are known, the model can accurately predict the desublimation phenomenon. The usefulness of the model in different engineering applications is also addressed
Models of Customer Behavior as a Basis of Marketing Strategy
Directory of Open Access Journals (Sweden)
T A Ivanova
2012-06-01
Full Text Available The article is devoted to the analysis of six main models of customer behavior in contemporary society and the specific tasks of marketing departments of companies at today's stage of development. The given models take into consideration: motives for choosing a product, the degree of product awareness and independence of choice, the degree of customer satisfaction with the product, lines and possibilities of making an impact on customer choice through marketing and promotion stimulation. The author believes that these models may serve as a basis in the formation of effective marketing strategies, as they describe the customers in all the stages of their actions in the process of buying products, accumulating and analyzing the experience of using them.
Directory of Open Access Journals (Sweden)
O. M. Bondarev
2014-11-01
Full Text Available Purpose. The objective is to determine the stress-strain state of supporting structures of the head car body and the traction transmission unit, which can be created in the operation of emergency situations, and to develop the measures aimed at improving the stress-strain state of these elements. Methodology. In order to achieve this objective, in performing the work an experimental determination of efforts and stress levels in the most loaded elements of supporting structures as well as the traction transmission units was conducted; design models for the theoretical determination of stress and effort levels were developed. Findings. Based on the analysis of the calculation results the best options for the upgrades, which have been put into the basis of proposals aimed at improving the strength indices, were revealed. Originality. Based on the experimental and theoretical studies, scientific monitoring of development works on modernization and improvement of strength indices of supporting structures of head cars of diesel trains DR1A was performed. Practical value. The technical solution to the measures, which are to be carried out beyond the limits of assigned operation lifetime for diesel train of the series specified was developed and transferred to the Ukrzaliznytsia experts to introduce the proposed measures on improving the strength indices.
Ramirez, A G; McAlister, A; Gallion, K J; Ramirez, V; Garza, I R; Stamm, K; de la Torre, J; Chalela, P
1995-01-01
A theory-based program that used peer modeling and a network of peer communicators to promote breast and cervical cancer screening was designed and implemented in a barrio of San Antonio with a population of approximately 25,000 adult women. The implementation process was evaluated and documented through field notes, archival documents, content analyses, interviews, surveys, etc. Over a 21-month period, a total of 156 new stories and a network for distribution of more than 80,000 print pieces carried messages about positive role models who were receiving Pap smears and mammograms. A group of 85 volunteers were recruited to promote screening; these volunteers reached 2000-3000 women each month with personal contacts in which cancer screening was encouraged. A small group of volunteers offered particularly intensive assistance to their peers, e.g., helping them to make and keep appointments for screening examinations. The theoretical communication model for the program, which maximizes audience and community participation as sources and channels for messages, was well suited for the cross-cultural application presented here.
Healing from Childhood Sexual Abuse: A Theoretical Model
Draucker, Claire Burke; Martsolf, Donna S.; Roller, Cynthia; Knapik, Gregory; Ross, Ratchneewan; Stidham, Andrea Warner
2011-01-01
Childhood sexual abuse is a prevalent social and health care problem. The processes by which individuals heal from childhood sexual abuse are not clearly understood. The purpose of this study was to develop a theoretical model to describe how adults heal from childhood sexual abuse. Community recruitment for an ongoing broader project on sexual…
Organizational Resilience: The Theoretical Model and Research Implication
Directory of Open Access Journals (Sweden)
Xiao Lei
2017-01-01
Full Text Available Organizations are all subject to a diverse and ever changing and uncertain environment. Under this situation organizations should develop a capability which can resist the emergency and recover from the disruption. Base on lot of literature, the paper provides the main concept of organizational resilience; construct the primary theoretical model and some implications for management.
Workshop IV – Cosmology-theoretical models/alternative scenarios ...
Indian Academy of Sciences (India)
Workshop IV – Cosmology-theoretical models/alternative scenarios: A report. ASIT BANERJEE. ½ and REZA TAVAKOL. 2. ½. Department of Physics, Jadavpur University, Calcutta 700 032, India. ¾. Astronomy Unit, School of Mathematical Sciences, Queen Mary and Westfield College, Mile End. Road, London E1 4NS, UK.
The development of a theoretical model to investigate factors
African Journals Online (AJOL)
user
ISSN 0378-5254 Journal of Family Ecology and Consumer Sciences, Vol 41, 2013. The development of a theoretical model to investigate factors associated with environmentally significant choice behaviour in the South ..... attitudes toward the behaviour, social pressure or subjective norms surrounding the behaviour.
Theoretical modeling and experimental analyses of laminated wood composite poles
Cheng Piao; Todd F. Shupe; Vijaya Gopu; Chung Y. Hse
2005-01-01
Wood laminated composite poles consist of trapezoid-shaped wood strips bonded with synthetic resin. The thick-walled hollow poles had adequate strength and stiffness properties and were a promising substitute for solid wood poles. It was necessary to develop theoretical models to facilitate the manufacture and future installation and maintenance of this novel...
Theoretical model analysis of molecular orientations in liquid protein ...
African Journals Online (AJOL)
In this study, some theoretical model functions have been used to explain the molecular behaviour of four different types of proteins; human haemoglobin, Insulin, egg-white lysozyme and β - globulin molecules in solution. The results of the computational fitting procedures showed that the dielectric dispersion of the protein ...
Modeling Marine Electromagnetic Survey with Radial Basis Function Networks
Directory of Open Access Journals (Sweden)
Agus Arif
2011-08-01
Full Text Available A marine electromagnetic survey is an engineering endeavour to discover the location and dimension of a hydrocarbon layer under an ocean floor. In this kind of survey, an array of electric and magnetic receivers are located on the sea floor and record the scattered, refracted and reflected electromagnetic wave, which has been transmitted by an electric dipole antenna towed by a vessel. The data recorded in receivers must be processed and further analysed to estimate the hydrocarbon location and dimension. To conduct those analyses successfuly, a radial basis function (RBF network could be employed to become a forward model of the input-output relationship of the data from a marine electromagnetic survey. This type of neural networks is working based on distances between its inputs and predetermined centres of some basis functions. A previous research had been conducted to model the same marine electromagnetic survey using another type of neural networks, which is a multi layer perceptron (MLP network. By comparing their validation and training performances (mean-squared errors and correlation coefficients, it is concluded that, in this case, the MLP network is comparatively better than the RBF network
Dynamics Model Abstraction Scheme Using Radial Basis Functions
Directory of Open Access Journals (Sweden)
Silvia Tolu
2012-01-01
Full Text Available This paper presents a control model for object manipulation. Properties of objects and environmental conditions influence the motor control and learning. System dynamics depend on an unobserved external context, for example, work load of a robot manipulator. The dynamics of a robot arm change as it manipulates objects with different physical properties, for example, the mass, shape, or mass distribution. We address active sensing strategies to acquire object dynamical models with a radial basis function neural network (RBF. Experiments are done using a real robot’s arm, and trajectory data are gathered during various trials manipulating different objects. Biped robots do not have high force joint servos and the control system hardly compensates all the inertia variation of the adjacent joints and disturbance torque on dynamic gait control. In order to achieve smoother control and lead to more reliable sensorimotor complexes, we evaluate and compare a sparse velocity-driven versus a dense position-driven control scheme.
Wielicki, Bruce A. (Principal Investigator); Barkstrom, Bruce R. (Principal Investigator); Baum, Bryan A.; Cess, Robert D.; Charlock, Thomas P.; Coakley, James A.; Green, Richard N.; Lee, Robert B., III; Minnis, Patrick; Smith, G. Louis
1995-01-01
The theoretical bases for the Release 1 algorithms that will be used to process satellite data for investigation of the Clouds and the Earth's Radiant Energy System (CERES) are described. The architecture for software implementation of the methodologies is outlined. Volume 1 provides both summarized and detailed overviews of the CERES Release 1 data analysis system. CERES will produce global top-of-the-atmosphere shortwave and longwave radiative fluxes at the top of the atmosphere, at the surface, and within the atmosphere by using the combination of a large variety of measurements and models. The CERES processing system includes radiance observations from CERES scanning radiometers, cloud properties derived from coincident satellite imaging radiometers, temperature and humidity fields from meteorological analysis models, and high-temporal-resolution geostationary satellite radiances to account for unobserved times. CERES will provide a continuation of the ERBE record and the lowest error climatology of consistent cloud properties and radiation fields. CERES will also substantially improve our knowledge of the Earth's surface radiation budget.
Theoretical Model of Engagement in the Context of Brand Communities
Directory of Open Access Journals (Sweden)
Flávia D\\u2019albergaria Freitas
2017-01-01
Full Text Available This essay proposes to refine the concept of consumer engagement in the context of brand communities. A comprehensive review of studies addressing the phenomenon of brand community was made. This paper follows the tradition of Marketing Research and Consumer Behavior, more specifically the perspective of cognitive psychology. The main theoretical foundation of the study is the Social Identity Theory (SIT, also incorporating relevant contributions from the perspective of Consumer Culture Theory (CCT. Therefore, this study contributes to the progress of research on the phenomenon of engagement in brand communities, proposing a theoretical model that relates engagement with its antecedents factors and reflective dimensions.
A comparison of graph-theoretic DNA hybridization models
Brijder, Robert; Gillis Joris; Van den Bussche, Jan
2012-01-01
We show that the graph-theoretic DNA hybridization models of pot tiles [4, 5] and of sticker complexes [3, 2] are equivalent. This allows one to carry over known results from one model to the other. In addition, we introduce the concept of “greedy” hybridization and compare it to “regular” hybridization. DNA hybridization; multiset-based graph grammars; self-assembly; database theory
Management Innovation – Designing And Testing A Theoretical Model
Directory of Open Access Journals (Sweden)
Bezdrob Muamer
2015-04-01
Full Text Available Management innovation – the introduction of management processes, structures and practices that are new to companies, is crucial to business success. Based on the existing literature on management innovation and a rigorous theoretical approach to model design and development, a theoretical model of management innovation that is applicable to immature and underdeveloped markets was designed. Using this model, the study shows that the context in which companies operate, as well as companies’ management background (proficiency, are directly and positively related to management innovation. The main implication of the research is that the existing management innovation theory is applicable to market conditions in the Federation of Bosnia and Herzegovina with only slight adaptation. Furthermore, this research provides important insights about the factors that affect the companies’ readiness to introduce innovative management structures, processes and practices.
Physical Basis for Interfacial Traction-Separation Models
International Nuclear Information System (INIS)
Neville R. Moody
2002-01-01
Many weapon components contain interfaces between dissimilar materials where cracks can initiate and cause failure. In recent years many researchers in the fracture community have adopted a cohesive zone model for simulating crack propagation (based upon traction-separation relations) Sandia is implementing this model in its ASCI codes. There is, however, one important obstacle to using a cohesive zone modeling approach. At the present time traction-separation relations are chosen in an ad hoc manner. The goal of the present work is to determine a physical basis for Traction-Separation (T-U) relations. This report presents results of a program aimed at determining the dependence of such relations on adhesive and bulk properties. The work focused on epoxy/solid interfaces, although the approach is applicable to a broad range of materials. Asymmetric double cantilevered beam and free surface film nanoindentation fracture toughness tests were used to generate a unique set of data spanning length scales, applied mode mixities, and yield (plastic) zone constraint. The crucial roles of crack tip plastic zone size and interfacial adhesion were defined by varying epoxy layer thickness and using coupling agents or special self-assembled monolayers in preparing the samples. The nature of the yield zone was probed in collaborative experiments run at the Advanced Photon Source. This work provides an understanding of the major phenomena governing polymer/solid interfacial fracture and identifies the essential features that must be incorporated in a T-U based cohesive zone failure model. We believe that models using physically based T-U relations provide a more accurate and widely applicable description of interface cracking than models using ad hoc relations. Furthermore, these T-U relations provide an essential tool for using models to tailor interface properties to meet design needs
Rastak, Narges; Riipinen, Ilona; Pandis, Spyros
2015-04-01
INTRODUCTION Organic aerosol particles often consist of thousands of compounds with different properties. One of these properties is solubility, which affects the hygroscopic growth and CCN activation of the organic particles. Here we investigate the CCN activation behavior of complex organic aerosols accounting for the distribution of solubilities present in these mixtures. METHODS We considered a monodisperse population of spherical aerosol particles consisting of an internal mixture of organic compounds. When exposed to water vapor, these particles were assumed to grow reaching a thermodynamic equilibrium between the water vapor and the particle phase. The composition of the organic and aqueous phases was determined on one hand by the equilibrium between the aqueous phase and water vapor, and on the other hand by the equilibrium of the aqueous phase with the organic insoluble phase. We modelled the mixtures with the help of a solubility basis set (SBS, analogous to the volatility basis set VBS, Donahue et al. 2006, 2011, 2012), describing the mixture with n surrogate compounds with varying solubilities. We varied the range and shape of the solubility distribution, and the number of components n in the distribution, we also assumed two different kinds of interactions between the organic compounds in the insoluble phase 1) ideal mixture, where organics limit each other's dissolution; 2) unity activity, where organics behave as pure compounds and do not influence each other's dissolution. Critical supersaturations and the dissolution behavior at the point of CCN activation were calculated utilizing the Köhler theory for all organic mixtures (denoted here as the "full model"). The full model predictions were compared with the three simplified models: 1) assuming complete dissolution of all compounds; 2) treating the organic mixture solubility with the hygroscopicity parameter κ and 3) assuming a fixed soluble fraction ɛ for each mixture. RESULTS AND CONCLUSIONS
Multiscale modeling of complex materials phenomenological, theoretical and computational aspects
Trovalusci, Patrizia
2014-01-01
The papers in this volume deal with materials science, theoretical mechanics and experimental and computational techniques at multiple scales, providing a sound base and a framework for many applications which are hitherto treated in a phenomenological sense. The basic principles are formulated of multiscale modeling strategies towards modern complex multiphase materials subjected to various types of mechanical, thermal loadings and environmental effects. The focus is on problems where mechanics is highly coupled with other concurrent physical phenomena. Attention is also focused on the historical origins of multiscale modeling and foundations of continuum mechanics currently adopted to model non-classical continua with substructure, for which internal length scales play a crucial role.
Directory of Open Access Journals (Sweden)
Vartsaba Vjera I.
2015-09-01
Full Text Available The article is aimed at the theoretical substantiation of the role and practicability of the both search and elaboration of innovative concepts, technologies and tools for regional management based on the contemporary management requirements of the managerial harmonization of goals, interests, relationships and interaction of participants in the regional markets under the respective acts on the part of public policy and regional management. A model for transforming resources of the regional social system into the economically and socially significant results of its development has been proposed. A graphical-analytic model for managing the status of dysergy-synergy of a socio-economic system by means of the organizational integration of its subsystems has been created, the coefficients for determining the degree of harmonization when controlling the system have been suggested. A base management algorithm for the 3С-Technology of harmonizing objectives and interests of the subsystems of a socio-economic system has been developed. Proceeding from the fact that the basis of the underlying algorithm for the managerial 3С-Technology is in its turn based on the algorithm for implementation of the management tool Strategic Planning (SP, which is supplemented by the mandatory use with the aim of the progressive transformation of the material resources of the system with an intensive and managed participation of the intellectual resources of the latter, becomes quite practical to explore and evaluate the relationship between the results obtained from the use of this technology
Understanding the inverse magnetocaloric effect through a simple theoretical model
Energy Technology Data Exchange (ETDEWEB)
Ranke, P.J. von, E-mail: von.ranke@uol.com.b [Instituto de Fisica Armando Dias Tavares-Universidade do Estado do Rio de Janeiro, Rua Sao Francisco Xavier, 524, Rio de Janeiro 20550-013 (Brazil); Alho, B.P.; Nobrega, E.P.; Oliveira, N.A. de [Instituto de Fisica Armando Dias Tavares-Universidade do Estado do Rio de Janeiro, Rua Sao Francisco Xavier, 524, Rio de Janeiro 20550-013 (Brazil)
2009-10-15
We investigated the inverse magnetocaloric effect using a theoretical magnetic model formed by two coupled magnetic lattices to describe a ferrimagnetic system. The influence of the compensation temperature, and the ferrimagnetic-paramagnetic phase transition on the magnetocaloric effect was analyzed. Also, a relation between the area under the magnetocaloric curve and the net magnetic moment of a ferrimagnetic system was established in this work.
Continuum damage modeling through theoretical and experimental pressure limit formulas
Directory of Open Access Journals (Sweden)
Fatima Majid
2018-01-01
Full Text Available In this paper, we developed a mathematical modeling to represent the damage of thermoplastic pipes. On the one hand, we adapted the theories of the rupture pressure to fit the High Density Polyethylene (HDPE case. Indeed, the theories for calculating the rupture pressure are multiple, designed originally for steels and alloys. For polymer materials, we have found that these theories can be adapted using a coefficient related to the nature of the studied material. The HDPE is characterized by two important values of pressure, deduced from the ductile form of the internal pressures evolution until burst. For this reason, we have designed an alpha coefficient taking into account these two pressures and giving a good approximation of the evolution of the experimental burst pressures through the theoretically corrected ones, using Faupel㒒s pressure formula. Then, we can deduce the evolution of the theoretical damage using the calculated pressures. On the other hand, two other mathematical models were undertaken. The first one has given rise to an adaptive model referring to an expression of the pressure as a function of the life fraction, the characteristic pressures and the critical life fraction. The second model represents a continuum damage model incorporating the pressure equations as a function of the life fraction and based on the burst pressure�s static damage model. These models represent important tools for industrials to assess the failure of thermoplastic pipes and proceed quick checks
A Theoretical Model for Meaning Construction through Constructivist Concept Learning
DEFF Research Database (Denmark)
Badie, Farshad
The central focus of this Ph.D. research is on ‘Logic and Cognition’ and, more specifically, this research covers the quintuple (Logic and Logical Philosophy, Philosophy of Education, Educational Psychology, Cognitive Science, Computer Science). The most significant contributions of this Ph...... of ‘learning’, ‘mentoring’, and ‘knowledge’ within learning and knowledge acquisition systems. Constructivism as an epistemology and as a model of knowing and, respectively as a theoretical model of learning builds up the central framework of this research....
Validation of theoretical models through measured pavement response
DEFF Research Database (Denmark)
Ullidtz, Per
1999-01-01
mechanics was quite different from the measured stress, the peak theoretical value being only half of the measured value.On an instrumented pavement structure in the Danish Road Testing Machine, deflections were measured at the surface of the pavement under FWD loading. Different analytical models were...... then used to derive the elastic parameters of the pavement layeres, that would produce deflections matching the measured deflections. Stresses and strains were then calculated at the position of the gauges and compared to the measured values. It was found that all analytical models would predict the tensile...
Information Theoretic Tools for Parameter Fitting in Coarse Grained Models
Kalligiannaki, Evangelia
2015-01-07
We study the application of information theoretic tools for model reduction in the case of systems driven by stochastic dynamics out of equilibrium. The model/dimension reduction is considered by proposing parametrized coarse grained dynamics and finding the optimal parameter set for which the relative entropy rate with respect to the atomistic dynamics is minimized. The minimization problem leads to a generalization of the force matching methods to non equilibrium systems. A multiplicative noise example reveals the importance of the diffusion coefficient in the optimization problem.
Theoretical Modeling of Rock Breakage by Hydraulic and Mechanical Tool
Directory of Open Access Journals (Sweden)
Hongxiang Jiang
2014-01-01
Full Text Available Rock breakage by coupled mechanical and hydraulic action has been developed over the past several decades, but theoretical study on rock fragmentation by mechanical tool with water pressure assistance was still lacking. The theoretical model of rock breakage by mechanical tool was developed based on the rock fracture mechanics and the solution of Boussinesq’s problem, and it could explain the process of rock fragmentation as well as predicating the peak reacting force. The theoretical model of rock breakage by coupled mechanical and hydraulic action was developed according to the superposition principle of intensity factors at the crack tip, and the reacting force of mechanical tool assisted by hydraulic action could be reduced obviously if the crack with a critical length could be produced by mechanical or hydraulic impact. The experimental results indicated that the peak reacting force could be reduced about 15% assisted by medium water pressure, and quick reduction of reacting force after peak value decreased the specific energy consumption of rock fragmentation by mechanical tool. The crack formation by mechanical or hydraulic impact was the prerequisite to improvement of the ability of combined breakage.
A theoretical approach to room acoustic simulations based on a radiative transfer model
DEFF Research Database (Denmark)
Ruiz-Navarro, Juan-Miguel; Jacobsen, Finn; Escolano, José
2010-01-01
A theoretical approach to room acoustic simulations based on a radiative transfer model is developed by adapting the classical radiative transfer theory from optics to acoustics. The proposed acoustic radiative transfer model expands classical geometrical room acoustic modeling algorithms...... by incorporating a propagation medium that absorbs and scatters radiation, handling both diffuse and non-diffuse reflections on boundaries and objects in the room. The main scope of this model is to provide a proper foundation for a wide number of room acoustic simulation models, in order to establish and unify...... their principles. It is shown that this room acoustic modeling technique establishes the basis of two recently proposed algorithms, the acoustic diffusion equation and the room acoustic rendering equation. Both methods are derived in detail using an analytical approximation and a simplified integral equation...
A Modified Theoretical Model of Intrinsic Hardness of Crystalline Solids
Dai, Fu-Zhi; Zhou, Yanchun
2016-01-01
Super-hard materials have been extensively investigated due to their practical importance in numerous industrial applications. To stimulate the design and exploration of new super-hard materials, microscopic models that elucidate the fundamental factors controlling hardness are desirable. The present work modified the theoretical model of intrinsic hardness proposed by Gao. In the modification, we emphasize the critical role of appropriately decomposing a crystal to pseudo-binary crystals, which should be carried out based on the valence electron population of each bond. After modification, the model becomes self-consistent and predicts well the hardness values of many crystals, including crystals composed of complex chemical bonds. The modified model provides fundamental insights into the nature of hardness, which can facilitate the quest for intrinsic super-hard materials. PMID:27604165
A Game-Theoretic Model for Distributed Programming by Contract
DEFF Research Database (Denmark)
Henriksen, Anders Starcke; Hvitved, Tom; Filinski, Andrzej
2009-01-01
We present an extension of the programming-by-contract (PBC) paradigm to a concurrent and distributed environment. Classical PBC is characterized by absolute conformance of code to its specification, assigning blame in case of failures, and a hierarchical, cooperative decomposition model – none...... of which extend naturally to a distributed environment with multiple administrative peers. We therefore propose a more nuanced contract model based on quantifiable performance of implementations; assuming responsibility for success; and a fundamentally adversarial model of system integration, where each...... component provider is optimizing its behavior locally, with respect to potentially conflicting demands. This model gives rise to a game-theoretic formulation of contract-governed process interactions that supports compositional reasoning about contract conformance....
Improving statistical reasoning theoretical models and practical implications
Sedlmeier, Peter
1999-01-01
This book focuses on how statistical reasoning works and on training programs that can exploit people''s natural cognitive capabilities to improve their statistical reasoning. Training programs that take into account findings from evolutionary psychology and instructional theory are shown to have substantially larger effects that are more stable over time than previous training regimens. The theoretical implications are traced in a neural network model of human performance on statistical reasoning problems. This book apppeals to judgment and decision making researchers and other cognitive scientists, as well as to teachers of statistics and probabilistic reasoning.
An Emerging Theoretical Model of Music Therapy Student Development.
Dvorak, Abbey L; Hernandez-Ruiz, Eugenia; Jang, Sekyung; Kim, Borin; Joseph, Megan; Wells, Kori E
2017-07-01
Music therapy students negotiate a complex relationship with music and its use in clinical work throughout their education and training. This distinct, pervasive, and evolving relationship suggests a developmental process unique to music therapy. The purpose of this grounded theory study was to create a theoretical model of music therapy students' developmental process, beginning with a study within one large Midwestern university. Participants (N = 15) were music therapy students who completed one 60-minute intensive interview, followed by a 20-minute member check meeting. Recorded interviews were transcribed, analyzed, and coded using open and axial coding. The theoretical model that emerged was a six-step sequential developmental progression that included the following themes: (a) Personal Connection, (b) Turning Point, (c) Adjusting Relationship with Music, (d) Growth and Development, (e) Evolution, and (f) Empowerment. The first three steps are linear; development continues in a cyclical process among the last three steps. As the cycle continues, music therapy students continue to grow and develop their skills, leading to increased empowerment, and more specifically, increased self-efficacy and competence. Further exploration of the model is needed to inform educators' and other key stakeholders' understanding of student needs and concerns as they progress through music therapy degree programs. © the American Music Therapy Association 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com
A Theoretical Model for the Prediction of Siphon Breaking Phenomenon
Energy Technology Data Exchange (ETDEWEB)
Bae, Youngmin; Kim, Young-In; Seo, Jae-Kwang; Kim, Keung Koo; Yoon, Juhyeon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)
2014-10-15
A siphon phenomenon or siphoning often refers to the movement of liquid from a higher elevation to a lower one through a tube in an inverted U shape (whose top is typically located above the liquid surface) under the action of gravity, and has been used in a variety of reallife applications such as a toilet bowl and a Greedy cup. However, liquid drainage due to siphoning sometimes needs to be prevented. For example, a siphon breaker, which is designed to limit the siphon effect by allowing the gas entrainment into a siphon line, is installed in order to maintain the pool water level above the reactor core when a loss of coolant accident (LOCA) occurs in an open-pool type research reactor. In this paper, we develop a theoretical model to predict the siphon breaking phenomenon. In this paper, a theoretical model to predict the siphon breaking phenomenon is developed. It is shown that the present model predicts well the fundamental features of the siphon breaking phenomenon and undershooting height.
The theoretical aspects of UrQMD & AMPT models
Energy Technology Data Exchange (ETDEWEB)
Saini, Abhilasha, E-mail: kashvini.abhi@gmail.com [Research Scholar, Department of Physics, Suresh Gyan vihar University, Jaipur (India); Bhardwaj, Sudhir, E-mail: sudhir.hep@gmail.com [Assistant professor, Govt. College of Engineering & Technology, Bikaner (India)
2016-05-06
The field of high energy physics is very challenging in carrying out theories and experiments to unlock the secrets of heavy ion collisions and still not cracked and solved completely. There are many theoretical queries; some may be due to the inherent causes like the non-perturbative nature of QCD in the strong coupling limit, also due to the multi-particle production and evolution during the heavy ion collisions which increase the complexity of the phenomena. So for the purpose of understanding the phenomena, variety of theories and ideas are developed which are usually implied in the form of Monte-Carlo codes. The UrQMD model and the AMPT model are discussed here in detail. These methods are useful in modeling the nuclear collisions.
Three General Theoretical Models in Sociology: An Articulated ?(Disunity?
Directory of Open Access Journals (Sweden)
Thaís García-Pereiro
2015-01-01
Full Text Available After merely a brief, comparative reconstruction of the three most general theoretical models underlying contemporary Sociology (atomic, systemic, and fluid it becomes necessary to review the question about the unity or plurality of Sociology, which is the main objective of this paper. To do so, the basic terms of the question are firstly updated by following the hegemonic trends in current studies of science. Secondly the convergences and divergences among the three models discussed are shown. Following some additional discussion, the conclusion is reached that contemporary Sociology is not unitary, and need not be so. It is plural, but its plurality is limited and articulated by those very models. It may therefore be portrayed as integrated and commensurable, to the extent that a partial and unstable (disunity may be said to exist in Sociology, which is not too far off from what happens in the natural sciences.
Physics of human cooperation: experimental evidence and theoretical models
Sánchez, Angel
2018-02-01
In recent years, many physicists have used evolutionary game theory combined with a complex systems perspective in an attempt to understand social phenomena and challenges. Prominent among such phenomena is the issue of the emergence and sustainability of cooperation in a networked world of selfish or self-focused individuals. The vast majority of research done by physicists on these questions is theoretical, and is almost always posed in terms of agent-based models. Unfortunately, more often than not such models ignore a number of facts that are well established experimentally, and are thus rendered irrelevant to actual social applications. I here summarize some of the facts that any realistic model should incorporate and take into account, discuss important aspects underlying the relation between theory and experiments, and discuss future directions for research based on the available experimental knowledge.
Graph theoretical model of a sensorimotor connectome in zebrafish.
Directory of Open Access Journals (Sweden)
Michael Stobb
Full Text Available Mapping the detailed connectivity patterns (connectomes of neural circuits is a central goal of neuroscience. The best quantitative approach to analyzing connectome data is still unclear but graph theory has been used with success. We present a graph theoretical model of the posterior lateral line sensorimotor pathway in zebrafish. The model includes 2,616 neurons and 167,114 synaptic connections. Model neurons represent known cell types in zebrafish larvae, and connections were set stochastically following rules based on biological literature. Thus, our model is a uniquely detailed computational representation of a vertebrate connectome. The connectome has low overall connection density, with 2.45% of all possible connections, a value within the physiological range. We used graph theoretical tools to compare the zebrafish connectome graph to small-world, random and structured random graphs of the same size. For each type of graph, 100 randomly generated instantiations were considered. Degree distribution (the number of connections per neuron varied more in the zebrafish graph than in same size graphs with less biological detail. There was high local clustering and a short average path length between nodes, implying a small-world structure similar to other neural connectomes and complex networks. The graph was found not to be scale-free, in agreement with some other neural connectomes. An experimental lesion was performed that targeted three model brain neurons, including the Mauthner neuron, known to control fast escape turns. The lesion decreased the number of short paths between sensory and motor neurons analogous to the behavioral effects of the same lesion in zebrafish. This model is expandable and can be used to organize and interpret a growing database of information on the zebrafish connectome.
Sample correlations of infinite variance time series models: an empirical and theoretical study
Directory of Open Access Journals (Sweden)
Jason Cohen
1998-01-01
Full Text Available When the elements of a stationary ergodic time series have finite variance the sample correlation function converges (with probability 1 to the theoretical correlation function. What happens in the case where the variance is infinite? In certain cases, the sample correlation function converges in probability to a constant, but not always. If within a class of heavy tailed time series the sample correlation functions do not converge to a constant, then more care must be taken in making inferences and in model selection on the basis of sample autocorrelations. We experimented with simulating various heavy tailed stationary sequences in an attempt to understand what causes the sample correlation function to converge or not to converge to a constant. In two new cases, namely the sum of two independent moving averages and a random permutation scheme, we are able to provide theoretical explanations for a random limit of the sample autocorrelation function as the sample grows.
Large-basis no-core shell model
Czech Academy of Sciences Publication Activity Database
Barrett, BR.; Navrátil, Petr; Vary, J. P.
2002-01-01
Roč. 704, č. 17 (2002), s. 254C-263C ISSN 0375-9474 Institutional research plan: CEZ:AV0Z1048901 Keywords : monte-carlo calculations * light-nuclei * cross-sections * ground-state * C12 * systems Subject RIV: BE - Theoretical Physics Impact factor: 1.568, year: 2002
Delayed hydride cracking: theoretical model testing to predict cracking velocity
International Nuclear Information System (INIS)
Mieza, Juan I.; Vigna, Gustavo L.; Domizzi, Gladys
2009-01-01
Pressure tubes from Candu nuclear reactors as any other component manufactured with Zr alloys are prone to delayed hydride cracking. That is why it is important to be able to predict the cracking velocity during the component lifetime from parameters easy to be measured, such as: hydrogen concentration, mechanical and microstructural properties. Two of the theoretical models reported in literature to calculate the DHC velocity were chosen and combined, and using the appropriate variables allowed a comparison with experimental results of samples from Zr-2.5 Nb tubes with different mechanical and structural properties. In addition, velocities measured by other authors in irradiated materials could be reproduced using the model described above. (author)
Theoretical model of intravascular paramagnetic tracers effect on tissue relaxation
DEFF Research Database (Denmark)
Kjølby, Birgitte Fuglsang; Østergaard, Leif; Kiselev, Valerij G
2006-01-01
The concentration of MRI tracers cannot be measured directly by MRI and is commonly evaluated indirectly using their relaxation effect. This study develops a comprehensive theoretical model to describe the transverse relaxation in perfused tissue caused by intravascular tracers. The model takes...... into account a number of individual compartments. The signal dephasing is simulated in a semianalytical way by embedding Monte Carlo simulations in the framework of analytical theory. This approach yields a tool for fast, realistic simulation of the change in the transverse relaxation. The results indicate...... with bulk blood. The enhancement of relaxation in tissue is due to the contrast in magnetic susceptibility between blood vessels and parenchyma induced by the presence of paramagnetic tracer. Beyond the perfusion measurements, the results can be applied to quantitation of functional MRI and to vessel size...
Directory of Open Access Journals (Sweden)
R. Du Preez
2003-10-01
Full Text Available This article is based on the conceptual theoretical model developed in Part 1 of this series of articles. The objective of this research is to identify female apparel consumer market segments on the basis of differentiating lifestyles, shopping orientation, cultural consciousness, store patronage and demographics. These profiles are discussed in full and the implications thereof for retailers, marketers and researchers are highlighted. A new conceptual model is proposed and recommendations are made for further research. Opsomming Hierdie artikel word gebaseer op die konseptuele teoretiese model wat reeds in Deel 1 van hierdie artikelreeks ontwikkel is. Die doel van hierdie navorsing is om marksegmente van vroue klere-kopers te identifiseer na aanleiding van hulle lewenstyle, kooporiëntasie, kulturele bewustheid, winkelvoorkeurgedrag en demografie. Hierdie profiele word volledig beskryf en die implikasies van die verskillende profiele vir kleinhandelaars, bemarkers en navorsers word uitgelig. ’n Nuwe konseptuele model word voorgestel en aanbevelings vir verdere navorsing word gemaak.
Diffusion Forecasting Model with Basis Functions from QR-Decomposition
Harlim, John; Yang, Haizhao
2017-12-01
The diffusion forecasting is a nonparametric approach that provably solves the Fokker-Planck PDE corresponding to Itô diffusion without knowing the underlying equation. The key idea of this method is to approximate the solution of the Fokker-Planck equation with a discrete representation of the shift (Koopman) operator on a set of basis functions generated via the diffusion maps algorithm. While the choice of these basis functions is provably optimal under appropriate conditions, computing these basis functions is quite expensive since it requires the eigendecomposition of an N× N diffusion matrix, where N denotes the data size and could be very large. For large-scale forecasting problems, only a few leading eigenvectors are computationally achievable. To overcome this computational bottleneck, a new set of basis functions constructed by orthonormalizing selected columns of the diffusion matrix and its leading eigenvectors is proposed. This computation can be carried out efficiently via the unpivoted Householder QR factorization. The efficiency and effectiveness of the proposed algorithm will be shown in both deterministically chaotic and stochastic dynamical systems; in the former case, the superiority of the proposed basis functions over purely eigenvectors is significant, while in the latter case forecasting accuracy is improved relative to using a purely small number of eigenvectors. Supporting arguments will be provided on three- and six-dimensional chaotic ODEs, a three-dimensional SDE that mimics turbulent systems, and also on the two spatial modes associated with the boreal winter Madden-Julian Oscillation obtained from applying the Nonlinear Laplacian Spectral Analysis on the measured Outgoing Longwave Radiation.
Vanschoonlandt, Femke; Vanderfaeillie, Johan; Van Holen, Frank; De Maeyer, Skrällan
2012-12-01
Foster parents are often faced with serious externalizing behaviors of their foster child. These behavioral problems may induce family stress and are related to less effective parenting and often increase. Foster children with behavioral problems are also more at risk of placement breakdown. An intervention to support foster parents of young foster children with externalizing behaviors is necessary to improve the effectiveness of foster placements. Based on research on effective parenting interventions and special needs of foster children, a treatment protocol was developed. This paper describes theoretical foundations for the content and form of the intervention and gives an overview of the modular treatment protocol. Preliminary outcomes of this intervention as well as challenges and future developments and research activities are discussed.
System of systems dependability – Theoretical models and applications examples
International Nuclear Information System (INIS)
Bukowski, L.
2016-01-01
The aim of this article is to generalise the concept of "dependability" in a way, that could be applied to all types of systems, especially the system of systems (SoS), operating under both normal and abnormal work conditions. In order to quantitatively assess the dependability we applied service continuity oriented approach. This approach is based on the methodology of service engineering and is closely related to the idea of resilient enterprise as well as to the concept of disruption-tolerant operation. On this basis a framework for evaluation of SoS dependability has been developed in a static as well as dynamic approach. The static model is created as a fuzzy logic-oriented advisory expert system and can be particularly useful at the design stage of SoS. The dynamic model is based on the risk oriented approach, and can be useful both at the design stage and for management of SoS. The integrated model of dependability can also form the basis for a new definition of the dependability engineering, namely as a superior discipline to reliability engineering, safety engineering, security engineering, resilience engineering and risk engineering. - Highlights: • A framework for evaluation of system of systems dependability is presented. • The model is based on the service continuity concept and consists of two parts. • The static part can be created as a fuzzy logic-oriented advisory expert system. • The dynamic, risk oriented part, is related to the concept of throughput chain. • A new definition of dependability engineering is proposed.
Gheribi, Aïmen E.; Chartrand, Patrice
2016-02-01
A theoretical model for the description of thermal conductivity of molten salt mixtures as a function of composition and temperature is presented. The model is derived by considering the classical kinetic theory and requires, for its parametrization, only information on thermal conductivity of pure compounds. In this sense, the model is predictive. For most molten salt mixtures, no experimental data on thermal conductivity are available in the literature. This is a hindrance for many industrial applications (in particular for thermal energy storage technologies) as well as an obvious barrier for the validation of the theoretical model. To alleviate this lack of data, a series of equilibrium molecular dynamics (EMD) simulations has been performed on several molten chloride systems in order to determine their thermal conductivity in the entire range of composition at two different temperatures: 1200 K and 1300 K. The EMD simulations are first principles type, as the potentials used to describe the interactions have been parametrized on the basis of first principle electronic structure calculations. In addition to the molten chlorides system, the model predictions are also compared to a recent similar EMD study on molten fluorides and with the few reliable experimental data available in the literature. The accuracy of the proposed model is within the reported numerical and/or experimental errors.
Gheribi, Aïmen E; Chartrand, Patrice
2016-02-28
A theoretical model for the description of thermal conductivity of molten salt mixtures as a function of composition and temperature is presented. The model is derived by considering the classical kinetic theory and requires, for its parametrization, only information on thermal conductivity of pure compounds. In this sense, the model is predictive. For most molten salt mixtures, no experimental data on thermal conductivity are available in the literature. This is a hindrance for many industrial applications (in particular for thermal energy storage technologies) as well as an obvious barrier for the validation of the theoretical model. To alleviate this lack of data, a series of equilibrium molecular dynamics (EMD) simulations has been performed on several molten chloride systems in order to determine their thermal conductivity in the entire range of composition at two different temperatures: 1200 K and 1300 K. The EMD simulations are first principles type, as the potentials used to describe the interactions have been parametrized on the basis of first principle electronic structure calculations. In addition to the molten chlorides system, the model predictions are also compared to a recent similar EMD study on molten fluorides and with the few reliable experimental data available in the literature. The accuracy of the proposed model is within the reported numerical and/or experimental errors.
Theoretical Models of Deliberative Democracy: A Critical Analysis
Directory of Open Access Journals (Sweden)
Tutui Viorel
2015-07-01
Full Text Available Abstract: My paper focuses on presenting and analyzing some of the most important theoretical models of deliberative democracy and to emphasize their limits. Firstly, I will mention James Fishkin‟s account of deliberative democracy and its relations with other democratic models. He differentiates between four democratic theories: competitive democracy, elite deliberation, participatory democracy and deliberative democracy. Each of these theories makes an explicit commitment to two of the following four “principles”: political equality, participation, deliberation, nontyranny. Deliberative democracy is committed to political equality and deliberation. Secondly, I will present Philip Pettit‟s view concerning the main constraints of deliberative democracy: the inclusion constraint, the judgmental constraint and the dialogical constraint. Thirdly, I will refer to Amy Gutmann and Dennis Thompson‟s conception regarding the “requirements” or characteristics of deliberative democracy: the reason-giving requirement, the accessibility of reasons, the binding character of the decisions and the dynamic nature of the deliberative process. Finally, I will discuss Joshua Cohen‟s “ideal deliberative procedure” which has the following features: it is free, reasoned, the parties are substantively equal and the procedure aims to arrive at rationally motivated consensus. After presenting these models I will provide a critical analysis of each one of them with the purpose of revealing their virtues and limits. I will make some suggestions in order to combine the virtues of these models, to transcend their limitations and to offer a more systematical account of deliberative democracy. In the next four sections I will take into consideration four main strategies for combining political and epistemic values (“optimistic”, “deliberative”, “democratic” and “pragmatic” and the main objections they have to face. In the concluding section
The protective action decision model: theoretical modifications and additional evidence.
Lindell, Michael K; Perry, Ronald W
2012-04-01
The Protective Action Decision Model (PADM) is a multistage model that is based on findings from research on people's responses to environmental hazards and disasters. The PADM integrates the processing of information derived from social and environmental cues with messages that social sources transmit through communication channels to those at risk. The PADM identifies three critical predecision processes (reception, attention, and comprehension of warnings or exposure, attention, and interpretation of environmental/social cues)--that precede all further processing. The revised model identifies three core perceptions--threat perceptions, protective action perceptions, and stakeholder perceptions--that form the basis for decisions about how to respond to an imminent or long-term threat. The outcome of the protective action decision-making process, together with situational facilitators and impediments, produces a behavioral response. In addition to describing the revised model and the research on which it is based, this article describes three applications (development of risk communication programs, evacuation modeling, and adoption of long-term hazard adjustments) and identifies some of the research needed to address unresolved issues. © 2011 Society for Risk Analysis.
Organisms modeling: The question of radial basis function networks
Directory of Open Access Journals (Sweden)
Muzy Alexandre
2014-01-01
Full Text Available There exists usually a gap between bio-inspired computational techniques and what biologists can do with these techniques in their current researches. Although biology is the root of system-theory and artifical neural networks, computer scientists are tempted to build their own systems independently of biological issues. This publication is a first-step re-evalution of an usual machine learning technique (radial basis funtion(RBF networks in the context of systems and biological reactive organisms.
A survey of game-theoretic models of cooperative advertising
DEFF Research Database (Denmark)
Jørgensen, Steffen; Zaccour, G.
2014-01-01
The paper surveys the literature on cooperative advertising in marketing channels (supply chains) using game theoretic methods. During the last decade, in particular, this literature has expanded considerably and has studied static as well as dynamic settings. The survey is divided into two main...... parts. The first one deals with simple marketing channels having one supplier and one reseller only. The second one covers marketing channels of a more complex structure, having more than one supplier and/or reseller. In the first part we find that a number of results carry over from static to dynamic...... problems of cooperative advertising also shows some similarities. The second part shows that models incorporating horizontal interaction on either or both layers of the supply chain are much less numerous than those supposing its absence. Participation rates in co-op advertising programs depend on inter...
Spatial Segregation, Redistribution and Welfare: A Theoretical Model
Directory of Open Access Journals (Sweden)
Tommaso Gabrieli
2016-03-01
Full Text Available This paper develops a theoretical model focusing on the effect that different neighborhood compositions can have on the formation of individual beliefs about economic opportunities. Specifically we highlight two effects that spatial segregation may have: (1 it can efficiently separate the individual effort choices of highly and low productive individuals, (2 it may imply that the median voter imposes a level of redistribution that is inefficient from the aggregate point of view. The trade-off implies that segregated and non-segregated cities may present very similar levels of aggregate welfare. We employ this framework to discuss how the structure of cities can play a role in the determination of US-type and Europe-type politico-economic equilibria and the implications for planning policies.
Theoretical temperature model with experimental validation for CLIC Accelerating Structures
AUTHOR|(CDS)2126138; Vamvakas, Alex; Alme, Johan
Micron level stability of the Compact Linear Collider (CLIC) components is one of the main requirements to meet the luminosity goal for the future $48 \\,km$ long underground linear accelerator. The radio frequency (RF) power used for beam acceleration causes heat generation within the aligned structures, resulting in mechanical movements and structural deformations. A dedicated control of the air- and water- cooling system in the tunnel is therefore crucial to improve alignment accuracy. This thesis investigates the thermo-mechanical behavior of the CLIC Accelerating Structure (AS). In CLIC, the AS must be aligned to a precision of $10\\,\\mu m$. The thesis shows that a relatively simple theoretical model can be used within reasonable accuracy to predict the temperature response of an AS as a function of the applied RF power. During failure scenarios or maintenance interventions, the RF power is turned off resulting in no heat dissipation and decrease in the overall temperature of the components. The theoretica...
Brenner, Anita C.; Zwally, H. Jay; Bentley, Charles R.; Csatho, Bea M.; Harding, David J.; Hofton, Michelle A.; Minster, Jean-Bernard; Roberts, LeeAnne; Saba, Jack L.; Thomas, Robert H.;
2012-01-01
The primary purpose of the GLAS instrument is to detect ice elevation changes over time which are used to derive changes in ice volume. Other objectives include measuring sea ice freeboard, ocean and land surface elevation, surface roughness, and canopy heights over land. This Algorithm Theoretical Basis Document (ATBD) describes the theory and implementation behind the algorithms used to produce the level 1B products for waveform parameters and global elevation and the level 2 products that are specific to ice sheet, sea ice, land, and ocean elevations respectively. These output products, are defined in detail along with the associated quality, and the constraints, and assumptions used to derive them.
Theoretical Model of God: The Key to Correct Exploration of the Universe
Kalanov, Temur Z.
2007-04-01
The problem of the correct approach to exploration of the Universe cannot be solved if there is no solution of the problem of existence of God (Creator, Ruler) in science. In this connection, theoretical proof of existence of God is proposed. The theoretical model of God -- as scientific proof of existence of God -- is the consequence of the system of the formulated axioms. The system of the axioms contains, in particular, the following premises: (1) all objects formed (synthesized) by man are characterized by the essential property: namely, divisibility into aspects; (2) objects which can be mentally divided into aspects are objects formed (synthesized); (3) the system ``Universe'' is mentally divided into aspects. Consequently, the Universe represents the system formed (synthesized); (4) the theorem of existence of God (i.e. Absolute, Creator, Ruler) follows from the principle of logical completeness of system of concepts: if the formed (synthesized) system ``Universe'' exists, then God exists as the Absolute, the Creator, the Ruler of essence (i.e. information) and phenomenon (i.e. material objects). Thus, the principle of existence of God -- the content of the theoretical model of God -- must be a starting-point and basis of correct gnosiology and science of 21 century.
A theoretical intellectual capital model applied to cities
Directory of Open Access Journals (Sweden)
José Luis Alfaro Navarro
2013-06-01
Full Text Available New Management Information Systems (MIS are necessary at local level as the main source of wealth creation. Therefore, tools and approaches that provide a full future vision of any organization should be a strategic priority for economic development. In this line, cities are “centers of knowledge and sources of growth and innovation” and integrated urban development policies are necessary. These policies support communication networks and optimize location structures as strategies that provide opportunities for social and democratic participation for the citizens. This paper proposes a theoretical model to measure and evaluate the cities intellectual capital that allows determine what we must take into account to make cities a source of wealth, prosperity, welfare and future growth. Furthermore, local intellectual capital provides a long run vision. Thus, in this paper we develop and explain how to implement a model to estimate intellectual capital in cities. In this sense, our proposal is to provide a model for measuring and managing intellectual capital using socio-economic indicators for cities. These indicators offer a long term picture supported by a comprehensive strategy for those who occupy the local space, infrastructure for implementation and management of the environment for its development.
A Production Model for Construction: A Theoretical Framework
Directory of Open Access Journals (Sweden)
Ricardo Antunes
2015-03-01
Full Text Available The building construction industry faces challenges, such as increasing project complexity and scope requirements, but shorter deadlines. Additionally, economic uncertainty and rising business competition with a subsequent decrease in profit margins for the industry demands the development of new approaches to construction management. However, the building construction sector relies on practices based on intuition and experience, overlooking the dynamics of its production system. Furthermore, researchers maintain that the construction industry has no history of the application of mathematical approaches to model and manage production. Much work has been carried out on how manufacturing practices apply to construction projects, mostly lean principles. Nevertheless, there has been little research to understand the fundamental mechanisms of production in construction. This study develops an in-depth literature review to examine the existing knowledge about production models and their characteristics in order to establish a foundation for dynamic production systems management in construction. As a result, a theoretical framework is proposed, which will be instrumental in the future development of mathematical production models aimed at predicting the performance and behaviour of dynamic project-based systems in construction.
Modeling opinion dynamics: Theoretical analysis and continuous approximation
International Nuclear Information System (INIS)
Pinasco, Juan Pablo; Semeshenko, Viktoriya; Balenzuela, Pablo
2017-01-01
Highlights: • We study a simple model of persuasion dynamics with long range pairwise interactions. • The continuous limit of the master equation is a nonlinear, nonlocal, first order partial differential equation. • We compute the analytical solutions to this equation, and compare them with the simulations of the dynamics. - Abstract: Frequently we revise our first opinions after talking over with other individuals because we get convinced. Argumentation is a verbal and social process aimed at convincing. It includes conversation and persuasion and the agreement is reached because the new arguments are incorporated. Given the wide range of opinion formation mathematical approaches, there are however no models of opinion dynamics with nonlocal pair interactions analytically solvable. In this paper we present a novel analytical framework developed to solve the master equations with non-local kernels. For this we used a simple model of opinion formation where individuals tend to get more similar after each interactions, no matter their opinion differences, giving rise to nonlinear differential master equation with non-local terms. Simulation results show an excellent agreement with results obtained by the theoretical estimation.
Platonov, A.; Zaitsev, Ie.; Opalski, L. J.
2017-08-01
The paper presents an overview of design methodology and results of experiments with a Prototype of highly efficient optimal adaptive feedback communication systems (AFCS), transmitting low frequency analog signals without coding. The paper emphasizes the role of the forward transmitter saturation as the factor that blocked implementation of theoretical results of pioneer (1960-1970s) and later research on FCS. Deepened analysis of the role of statistical fitting condition in adequate formulation and solution of AFCS optimization task is given. Solution of the task - optimal transmission/reception algorithms is presented in the form useful for elaboration of the hardware/software Prototype. A notable particularity of the Prototype is absence of the encoding/decoding units, whose functions are realized by the adaptive pulse amplitude modulator (PAM) of the forward transmitter (FT) and estimating/controlling algorithm in the receiver of base station (BS). Experiments confirm that the Prototype transmits signals from FT to BS "perfectly": with the bit rate equal to the capacity of the system, and with limit energy [J/bit] and spectral [bps/Hz] efficiency. Another, not less important and confirmed experimentally, particularity of AFCS is its capability to adjust parameters of FT and BS to the characteristics of scenario of application and maintain the ideal regime of transmission including spectralenergy efficiency. AFCS adjustment can be made using BS estimates of mean square error (MSE). The concluding part of the paper contains discussion of the presented results, stressing capability of AFCS to solve problems appearing in development of dense wireless networks.
Numerical modeling and the physical basis of seismic discriminants
International Nuclear Information System (INIS)
Denny, M.D.
1993-01-01
Accurate seismic event discrimination is critical to detection of nuclear explosions. Numerical modeling applied to seismic event discrimination can lead to increased reliability of proliferation detection. It is particularly applicable to error budgeting and to understanding explosion and earthquake phenomenologies. There also is a need for minimum requirements to validate the models used in numerical modeling
Steenge, A.E.
1991-01-01
In this paper we provide conditions for the existence of non-negative homogeneous matrices of dimensions commodity × commodity or industry × industry in the SNA framework. These matrices are shown to satisfy all conditions underlying the commodity technology model. We point out that because the
A theoretical model for the Lorentz force particle analyzer
Moreau, René; Tao, Zhen; Wang, Xiaodong
2016-07-01
In a previous paper [X. Wang et al., J. Appl. Phys. 120, 014903 (2016)], several experimental devices have been presented, which demonstrate the efficiency of electromagnetic techniques for detecting and sizing electrically insulating particles entrained in the flow of a molten metal. In each case, a non-uniform magnetic field is applied across the flow of the electrically conducting liquid, thereby generating a braking Lorentz force on this moving medium and a reaction force on the magnet, which tends to be entrained in the flow direction. The purpose of this letter is to derive scaling laws for this Lorentz force from an elementary theoretical model. For simplicity, as in the experiments, the flowing liquid is modeled as a solid body moving with a uniform velocity U. The eddy currents in the moving domain are derived from the classic induction equation and Ohm's law, and expressions for the Lorentz force density j ×B and for its integral over the entire moving domain follow. The insulating particles that are eventually present and entrained with this body are then treated as small disturbances in a classic perturbation analysis, thereby leading to scaling laws for the pulses they generate in the Lorentz force. The purpose of this letter is both to illustrate the eddy currents without and with insulating particles in the electrically conducting liquid and to derive a key relation between the pulses in the Lorentz force and the main parameters (particle volume and dimensions of the region subjected to the magnetic field).
posttraumatic stress disorder: a theoretical model of the hyperarousal subtype
Directory of Open Access Journals (Sweden)
Charles Stewart Weston
2014-04-01
Full Text Available Posttraumatic stress disorder (PTSD is a frequent and distressing mental disorder, about which much remains to be learned. It is a heterogeneous disorder; the hyperarousal subtype (about 70% of occurrences and simply termed PTSD in this paper is the topic of this article, but the dissociative subtype (about 30% of occurrences and likely involving quite different brain mechanisms is outside its scope. A theoretical model is presented that integrates neuroscience data on diverse brain regions known to be involved in PTSD, and extensive psychiatric findings on the disorder. Specifically, the amygdala is a multifunctional brain region that is crucial to PTSD, and processes peritraumatic hyperarousal on grounded cognition principles to produce hyperarousal symptoms. Amygdala activity also modulates hippocampal function, which is supported by a large body of evidence, and likewise amygdala activity modulates several brainstem regions, visual cortex, rostral anterior cingulate cortex (rACC, and medial orbitofrontal cortex (mOFC, to produce diverse startle, visual, memory, numbing, anger, and recklessness symptoms. Additional brain regions process other aspects of peritraumatic responses to produce further symptoms. These contentions are supported by neuroimaging, neuropsychological, neuroanatomical, physiological, cognitive, and behavioral evidence. Collectively, the model offers an account of how responses at the time of trauma are transformed into an extensive array of the 20 PTSD symptoms that are specified in the Diagnostic and Statistical Manual of Mental Disorders, 5th edition. It elucidates the neural mechanisms of a specific form of psychopathology, and accords with the Research Domain Criteria framework
Strengthening Theoretical Testing in Criminology Using Agent-based Modeling.
Johnson, Shane D; Groff, Elizabeth R
2014-07-01
The Journal of Research in Crime and Delinquency ( JRCD ) has published important contributions to both criminological theory and associated empirical tests. In this article, we consider some of the challenges associated with traditional approaches to social science research, and discuss a complementary approach that is gaining popularity-agent-based computational modeling-that may offer new opportunities to strengthen theories of crime and develop insights into phenomena of interest. Two literature reviews are completed. The aim of the first is to identify those articles published in JRCD that have been the most influential and to classify the theoretical perspectives taken. The second is intended to identify those studies that have used an agent-based model (ABM) to examine criminological theories and to identify which theories have been explored. Ecological theories of crime pattern formation have received the most attention from researchers using ABMs, but many other criminological theories are amenable to testing using such methods. Traditional methods of theory development and testing suffer from a number of potential issues that a more systematic use of ABMs-not without its own issues-may help to overcome. ABMs should become another method in the criminologists toolbox to aid theory testing and falsification.
Experimental Investigation and Theoretical Modeling of Nanosilica Activity in Concrete
Directory of Open Access Journals (Sweden)
Han-Seung Lee
2014-01-01
Full Text Available This paper presents experimental investigations and theoretical modeling of the hydration reaction of nanosilica blended concrete with different water-to-binder ratios and different nanosilica replacement ratios. The developments of chemically bound water contents, calcium hydroxide contents, and compressive strength of Portland cement control specimens and nanosilica blended specimens were measured at different ages: 1 day, 3 days, 7 days, 14 days, and 28 days. Due to the pozzolanic reaction of nanosilica, the contents of calcium hydroxide in nanosilica blended pastes are considerably lower than those in the control specimens. Compared with the control specimens, the extent of compressive strength enhancement in the nanosilica blended specimens is much higher at early ages. Additionally, a blended cement hydration model that considers both the hydration reaction of cement and the pozzolanic reaction of nanosilica is proposed. The properties of nanosilica blended concrete during hardening were evaluated using the degree of hydration of cement and the reaction degree of nanosilica. The calculated chemically bound water contents, calcium hydroxide contents, and compressive strength were generally consistent with the experimental results.
Theoretical Modelling Methods for Thermal Management of Batteries
Directory of Open Access Journals (Sweden)
Bahman Shabani
2015-09-01
Full Text Available The main challenge associated with renewable energy generation is the intermittency of the renewable source of power. Because of this, back-up generation sources fuelled by fossil fuels are required. In stationary applications whether it is a back-up diesel generator or connection to the grid, these systems are yet to be truly emissions-free. One solution to the problem is the utilisation of electrochemical energy storage systems (ESS to store the excess renewable energy and then reusing this energy when the renewable energy source is insufficient to meet the demand. The performance of an ESS amongst other things is affected by the design, materials used and the operating temperature of the system. The operating temperature is critical since operating an ESS at low ambient temperatures affects its capacity and charge acceptance while operating the ESS at high ambient temperatures affects its lifetime and suggests safety risks. Safety risks are magnified in renewable energy storage applications given the scale of the ESS required to meet the energy demand. This necessity has propelled significant effort to model the thermal behaviour of ESS. Understanding and modelling the thermal behaviour of these systems is a crucial consideration before designing an efficient thermal management system that would operate safely and extend the lifetime of the ESS. This is vital in order to eliminate intermittency and add value to renewable sources of power. This paper concentrates on reviewing theoretical approaches used to simulate the operating temperatures of ESS and the subsequent endeavours of modelling thermal management systems for these systems. The intent of this review is to present some of the different methods of modelling the thermal behaviour of ESS highlighting the advantages and disadvantages of each approach.
A theoretical model for analysing gender bias in medicine
Directory of Open Access Journals (Sweden)
Johansson Eva E
2009-08-01
Full Text Available Abstract During the last decades research has reported unmotivated differences in the treatment of women and men in various areas of clinical and academic medicine. There is an ongoing discussion on how to avoid such gender bias. We developed a three-step-theoretical model to understand how gender bias in medicine can occur and be understood. In this paper we present the model and discuss its usefulness in the efforts to avoid gender bias. In the model gender bias is analysed in relation to assumptions concerning difference/sameness and equity/inequity between women and men. Our model illustrates that gender bias in medicine can arise from assuming sameness and/or equity between women and men when there are genuine differences to consider in biology and disease, as well as in life conditions and experiences. However, gender bias can also arise from assuming differences when there are none, when and if dichotomous stereotypes about women and men are understood as valid. This conceptual thinking can be useful for discussing and avoiding gender bias in clinical work, medical education, career opportunities and documents such as research programs and health care policies. Too meet the various forms of gender bias, different facts and measures are needed. Knowledge about biological differences between women and men will not reduce bias caused by gendered stereotypes or by unawareness of health problems and discrimination associated with gender inequity. Such bias reflects unawareness of gendered attitudes and will not change by facts only. We suggest consciousness-rising activities and continuous reflections on gender attitudes among students, teachers, researchers and decision-makers.
A theoretical model for analysing gender bias in medicine.
Risberg, Gunilla; Johansson, Eva E; Hamberg, Katarina
2009-08-03
During the last decades research has reported unmotivated differences in the treatment of women and men in various areas of clinical and academic medicine. There is an ongoing discussion on how to avoid such gender bias. We developed a three-step-theoretical model to understand how gender bias in medicine can occur and be understood. In this paper we present the model and discuss its usefulness in the efforts to avoid gender bias. In the model gender bias is analysed in relation to assumptions concerning difference/sameness and equity/inequity between women and men. Our model illustrates that gender bias in medicine can arise from assuming sameness and/or equity between women and men when there are genuine differences to consider in biology and disease, as well as in life conditions and experiences. However, gender bias can also arise from assuming differences when there are none, when and if dichotomous stereotypes about women and men are understood as valid. This conceptual thinking can be useful for discussing and avoiding gender bias in clinical work, medical education, career opportunities and documents such as research programs and health care policies. Too meet the various forms of gender bias, different facts and measures are needed. Knowledge about biological differences between women and men will not reduce bias caused by gendered stereotypes or by unawareness of health problems and discrimination associated with gender inequity. Such bias reflects unawareness of gendered attitudes and will not change by facts only. We suggest consciousness-rising activities and continuous reflections on gender attitudes among students, teachers, researchers and decision-makers.
Mesorad dose assessment model. Volume 1. Technical basis
International Nuclear Information System (INIS)
Scherpelz, R.I.; Bander, T.J.; Athey, G.F.; Ramsdell, J.V.
1986-03-01
MESORAD is a dose assessment model for emergency response applications. Using release data for as many as 50 radionuclides, the model calculates: (1) external doses resulting from exposure to radiation emitted by radionuclides contained in elevated or deposited material; (2) internal dose commitment resulting from inhalation; and (3) total whole-body doses. External doses from airborne material are calculated using semi-infinite and finite cloud approximations. At each stage in model execution, the appropriate approximation is selected after considering the cloud dimensions. Atmospheric processes are represented in MESORAD by a combination of Lagrangian puff and Gaussian plume dispersion models, a source depletion (deposition velocity) dry deposition model, and a wet deposition model using washout coefficients based on precipitation rates
Theoretical modeling of molar volume and thermal expansion
Energy Technology Data Exchange (ETDEWEB)
Lu Xiaogang [Department of Materials Science and Engineering, Royal Institute of Technology, 100 44 Stockholm (Sweden)]. E-mail: gang@mse.kth.se; Selleby, Malin [Department of Materials Science and Engineering, Royal Institute of Technology, 100 44 Stockholm (Sweden); Sundman, Bo [Department of Materials Science and Engineering, Royal Institute of Technology, 100 44 Stockholm (Sweden)
2005-05-15
The molar volumes and thermal expansions of transition cubic metals were studied by means of the Calphad approach and the Debye-Grueneisen model. Experimental data were collected and assessed using Calphad procedures, and consistent results were obtained which give the best description of all experimental data. In order to put the prediction of the thermodynamic properties of metastable phases on a sound physical basis, the Debye-Grueneisen model was chosen to account for the vibrational contribution and calculate the coefficients of linear thermal expansion (CLEs) of stable cubic metals. Two approximations for Grueneisen parameter {gamma}, i.e. Slater's and Dugdale and MacDonald's expressions were adopted. A modified calculation scheme, first proposed by Wang et al., was derived in a straightforward way and used to evaluate the Debye temperature from ab initio electronic total-energy calculations at T = 0 K. The thermal electronic contribution to CLE was also evaluated from the electronic density of states. The calculated total CLEs were compared with those from the Calphad assessments. A satisfactory agreement is reached.
Theoretical modeling of molar volume and thermal expansion
International Nuclear Information System (INIS)
Lu Xiaogang; Selleby, Malin; Sundman, Bo
2005-01-01
The molar volumes and thermal expansions of transition cubic metals were studied by means of the Calphad approach and the Debye-Grueneisen model. Experimental data were collected and assessed using Calphad procedures, and consistent results were obtained which give the best description of all experimental data. In order to put the prediction of the thermodynamic properties of metastable phases on a sound physical basis, the Debye-Grueneisen model was chosen to account for the vibrational contribution and calculate the coefficients of linear thermal expansion (CLEs) of stable cubic metals. Two approximations for Grueneisen parameter γ, i.e. Slater's and Dugdale and MacDonald's expressions were adopted. A modified calculation scheme, first proposed by Wang et al., was derived in a straightforward way and used to evaluate the Debye temperature from ab initio electronic total-energy calculations at T = 0 K. The thermal electronic contribution to CLE was also evaluated from the electronic density of states. The calculated total CLEs were compared with those from the Calphad assessments. A satisfactory agreement is reached
Mathematical modelling as basis for efficient enterprise management
Directory of Open Access Journals (Sweden)
Kalmykova Svetlana
2017-01-01
Full Text Available The choice of the most effective HR- management style at the enterprise is based on modeling various socio-economic situations. The article describes the formalization of the managing processes aimed at the interaction between the allocated management subsystems. The mathematical modelling tools are used to determine the time spent on recruiting personnel for key positions in the management hierarchy selection.
A field-theoretic approach to Spin Foam models in Quantum Gravity
Vitale, Patrizia
2011-01-01
We present an introduction to Group Field Theory models, motivating them on the basis of their relationship with discretized BF models of gravity. We derive the Feynmann rules and compute quantum corrections in the coherent states basis.
Membranes and theoretical modeling of membrane distillation: a review.
Khayet, Mohamed
2011-05-11
Membrane distillation (MD) is one of the non-isothermal membrane separation processes used in various applications such desalination, environmental/waste cleanup, food, etc. It is known since 1963 and is still being developed at laboratory stage for different purposes and not fully implemented in industry. An abrupt increase in the number of papers on MD membrane engineering (i.e. design, fabrication and testing in MD) is seen since only 6 years ago. The present paper offers a comprehensive MD state-of-the-art review covering a wide range of commercial membranes, MD membrane engineering, their MD performance, transport mechanisms, experimental and theoretical modeling of different MD configurations as well as recent developments in MD. Improved MD membranes with specific morphology, micro- and nano-structures are highly demanded. Membranes with different pore sizes, porosities, thicknesses and materials as well as novel structures are required in order to carry out systematic MD studies for better understanding mass transport in different MD configurations, thereby improving the MD performance and looking for MD industrialization. Copyright © 2010 Elsevier B.V. All rights reserved.
Someya, Hiroshi; Yamamura, Masayuki; Sakamoto, Kensaku
This paper discusses DNA-based stochastic optimizations under the constraint that the search starts from a given point in a search space. Generally speaking, a stochastic optimization method explores a search space and finds out the optimum or a sub-optimum after many cycles of trials and errors. This search process could be implemented efficiently by ``molecular computing'', which processes DNA molecules by the techniques of molecular biology to generate and evaluate a vast number of solution candidates at a time. We assume the exploration starting from a single point, and propose a method to embody DNA-based optimization under this constraint, because this method has a promising application in the research field of protein engineering. In this application, a string of nucleotide bases (a base sequence) encodes a protein possessing a specific activity, which could be given as a value of an objective function. Thus, a problem of obtaining a protein with the optimum or a sub-optimum about the desired activity corresponds to a combinatorial problem of obtaining a base sequence giving the optimum or a sub-optimum in the sequence space. Biologists usually modify a base sequence corresponding to a naturally occurring protein into another sequence giving a desired activity. In other words, they explore the space in the proximity of a natural protein as a start point. We first examined if the optimization methods that involve a single start point, such as simulated annealing, Gibbs sampler, and MH algorithms, can be implemented by DNA-based operations. Then, we proposed an application of genetic algorithm, and examined the performance of this application on a model fitness landscape by computer experiments. These experiments gave helpful guidelines in the embodiments of DNA-based stochastic optimization, including a better design of crossover operator.
Topological basis realization for BMW algebra and Heisenberg XXZ spin chain model
Liu, Bo; Xue, Kang; Wang, Gangcheng; Liu, Ying; Sun, Chunfang
2015-04-01
In this paper, we study three-dimensional (3D) reduced Birman-Murakami-Wenzl (BMW) algebra based on topological basis theory. Several examples of BMW algebra representations are reviewed. We also discuss a special solution of BMW algebra, which can be used to construct Heisenberg XXZ model. The theory of topological basis provides a useful method to solve quantum spin chain models. It is also shown that the ground state of XXZ spin chain is superposition state of topological basis.
Insects as models to study the epigenetic basis of disease.
Mukherjee, Krishnendu; Twyman, Richard M; Vilcinskas, Andreas
2015-07-01
Epigenetic inheritance refers to changes in gene expression that are heritable across generations but are not caused by changes in the DNA sequence. Many environmental factors are now known to cause epigenetic changes, including the presence of pathogens, parasites, harmful chemicals and other stress factors. There is increasing evidence that transcriptional reprogramming caused by epigenetic modifications can be passed from parents to offspring. Indeed, diseases such as cancer can occur in the offspring due to epigenetically-inherited gene expression profiles induced by stress experienced by the parent. Empirical studies to investigate the role of epigenetics in trans-generational gene regulation and disease require appropriate model organisms. In this review, we argue that selected insects can be used as models for human diseases with an epigenetic component because the underlying molecular mechanisms (DNA methylation, histone acetylation and the expression of microRNAs) are evolutionarily conserved. Insects offer a number of advantages over mammalian models including ethical acceptability, short generation times and the potential to investigate complex interacting parameters such as fecundity, longevity, gender ratio, and resistance to pathogens, parasites and environmental stress. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.
Audiovisual Rehabilitation in Hemianopia: A Model-Based Theoretical Investigation
Magosso, Elisa; Cuppini, Cristiano; Bertini, Caterina
2017-01-01
translate visual stimuli into short-latency saccades, possibly moving the stimuli into visual detection regions. The retina-SC-extrastriate circuit is related to restitutive effects: visual stimuli can directly elicit visual detection with no need for eye movements. Model predictions and assumptions are critically discussed in view of existing behavioral and neurophysiological data, forecasting that other oculomotor compensatory mechanisms, beyond short-latency saccades, are likely involved, and stimulating future experimental and theoretical investigations. PMID:29326578
Audiovisual Rehabilitation in Hemianopia: A Model-Based Theoretical Investigation
Directory of Open Access Journals (Sweden)
Elisa Magosso
2017-12-01
circuit can translate visual stimuli into short-latency saccades, possibly moving the stimuli into visual detection regions. The retina-SC-extrastriate circuit is related to restitutive effects: visual stimuli can directly elicit visual detection with no need for eye movements. Model predictions and assumptions are critically discussed in view of existing behavioral and neurophysiological data, forecasting that other oculomotor compensatory mechanisms, beyond short-latency saccades, are likely involved, and stimulating future experimental and theoretical investigations.
Direct Simulation Monte Carlo for Atmospheric Entry. 1. Theoretical Basis and Physical Models
2009-09-01
of Nonequilibrium Flow in Low Power Hydrogen Arcjets ,” Physics of Fluids. Vol. 9, 1997, pp. 3086-3095. [47] Gallis, M.A. and Harvey, J.K., “Atomic...method (DSMC) has evolved over 40 years into a powerful numerical technique for the computation of complex, nonequilibrium gas flows. In this context...nonequilibrium means that the velocity distribution function is not in an equilibrium form due to a low number of intermolecular collisions within a
Experimental and Theoretical Basis for a Closed-Form Spectral BRDF Model
2015-09-17
Resnick et al., the emissivity 38 of the surface is given as follows:[55] ~ε = 1− ρ00(ω̂s) −ρ10(ω̂s) −ρ20(ω̂s) −ρ30(ω̂s...Opt., 37: 5271–5283 (1998). 55. Resnick , A., C. Persons, and G. Lindquist. “Polarized Emissivity and Kirchhoff’s Law,” Appl. Opt., 38: 1384–1387 (Mar
Wu, Junyan; Wang, Jie; Zhang, Junlong
2015-05-01
Through the consultation of TCM ancient classical theory, the relationship of kidney essence, marrow and brain is analyzed. It is discovered that the degenerative brain diseases, represented by Alzheimer's disease (AD) and Parkinson's disease (PD) share the same etiological basis as "kidney essence deficiency and brain marrow emptiness" and have the mutual pathological outcomes as yang qi declining. The Governor Vessel gathers yang qi of the whole body and maintains the normal functional activity of zangfu organs in the human body through the storage, regulation and invigoration of yang qi. It is viewed that the theory of the Governor Vessel is applied to treat the different degenerative brain diseases, which provides the theoretic support and practice guide for the thought of TCM as the same therapeutic program for the different diseases. As a result, the degenerative brain diseases can be retarded and the approach is provided to the effective prevention and treatment of degenerative diseases in central nerve system:
Recent Advances in the Theoretical Modeling of Pulsating Low-mass He-core White Dwarfs
Córsico, A. H.; Althaus, L. G.; Calcaferro, L. M.; Serenelli, A. M.; Kepler, S. O.; Jeffery, C. S.
2017-03-01
Many extremely low-mass (ELM) white-dwarf (WD) stars are currently being found in the field of the Milky Way. Some of these stars exhibit long-period nonradial g-mode pulsations, and constitute the class of ELMV pulsating WDs. In addition, several low-mass pre-WDs, which could be precursors of ELM WDs, have been observed to show short-period photometric variations likely due to nonradial p modes and radial modes. They could constitute a new class of pulsating low-mass pre-WD stars, the pre-ELMV stars. Here, we present the recent results of a thorough theoretical study of the nonadiabatic pulsation properties of low-mass He-core WDs and pre-WDs on the basis of fully evolutionary models representative of these stars.
Electron transport code theoretical basis
International Nuclear Information System (INIS)
Dubi, A.; Horowitz, Y.S.
1978-04-01
This report mainly describes the physical and mathematical considerations involved in the treatment of the multiple collision processes. A brief description is given of the traditional methods used in electron transport via Monte Carlo, and a somewhat more detailed description, of the approach to be used in the presently developed code
International Nuclear Information System (INIS)
Barbu, A.
2008-01-01
Recent developments in multi-scale modelling, based on atomic scale calculations, are leading to a growing conviction that modelling will soon be used to design material components for nuclear reactors. In this article we discuss this assumption on the basis of the relationship between experimental studies and theoretical calculations of the microstructural evolution of materials under irradiation. In the first part of the paper, the available numerical models for long term microstructural evolutions are briefly reviewed. The experimental methods are presented in a second part. In the third part, several examples of fruitful relationships between modelling and experiments are discussed. The first example deals with the isochronal electrical resistivity recovery of electron irradiated ultra pure iron at 14 K, the second one is dedicated to the microstructural evolution of ferritic model alloy during continuous irradiation with 1 MeV electrons at large fluences, the third one is the modelling of He desorption of helium implanted iron, and the fourth example concerns the mechanisms of formation of solute rich clusters observed by 3-dimensional atom probe in irradiated pressure vessel steels of water pressurized nuclear reactors
Perancangan Model Basis Data Sistem Operasional Berbasiskan Customer Relationship Management
Directory of Open Access Journals (Sweden)
Tanty Oktavia
2013-12-01
Full Text Available Data is a very important asset for a company since it describes the company’s running processes. Database as a part of the information system components provides a big influence in helping data integration in a company. Therefore, we need a system which can facilitate the availability of data to be processed and used as needed, This study takes a company engaged in the sale of bike and spare parts, namely PT TDI, as the object of the study. At this time, PT TDI uses an integrated system in helping the company's operations. Along with thevision and mission, PT TDI intends to build a new operating system by applying the concept of Customer Relationship Management (CRM which is believed to assist the company in maintaining relationships with customers using web-based platform. It aims to facilitate interaction with customers so that it can be done anytime and anywhere. This study implements the database design life cycle adjusted to the component aspects of CRM. The result achieved is a model that combines database CRM systems that can help companies improve relationships with customers.
Ultimate Limit State Model Basis for Assessment of Offshore Wind Energy Converters
DEFF Research Database (Denmark)
Thöns, Sebastian; Faber, M. H.; Rücker, W.
2012-01-01
This paper establishes the model basis regarding the ultimate limit state consisting of structural, loading, and probabilistic models of the support structure of offshore wind energy converters together with a sensitivity study. The model basis is part of a risk based assessment and monitoring...... structure and the tripod structure are determined with a geometrically and materially nonlinear finite element analysis. The observed failure mechanisms are the basis for the definition of the ultimate limit state responses. A probabilistic model accounting for the uncertainties involved is derived...
A theoretical microbial contamination model for a human Mars mission
Lupisella, Mark Lewis
Contamination from a human presence on Mars could significantly compromise the search for extraterrestrial life. In particular, the difficulties in controlling microbial contamination, the potential for terrestrial microbes to grow, evolve, compete, and modify the Martian environment, and the likely microbial nature of putative Martian life, make microbial contamination worthy of focus as we begin to plan for a human mission to Mars. This dissertation describes a relatively simple theoretical model that can be used to explore how microbial contamination from a human Mars mission might survive and grow in the Martian soil environment surrounding a habitat. A user interface has been developed to allow a general practitioner to choose values and functions for almost all parameters ranging from the number of astronauts to the half-saturation constants for microbial growth. Systematic deviations from a baseline set of parameter values are explored as potential plausible scenarios for the first human Mars missions. The total viable population and population density are the primary state variables of interest, but other variables such as the total number of births and total dead and viable microbes are also tracked. The general approach was to find the most plausible parameter value combinations that produced a population density of 1 microbe/cm3 or greater, a threshold that was used to categorize the more noteworthy populations for subsequent analysis. Preliminary assessments indicate that terrestrial microbial contamination resulting from leakage from a limited human mission (perhaps lasting up to 5 months) will not likely become a problematic population in the near-term as long as reasonable contamination control measures are implemented (for example, a habitat leak rate no greater than 1% per hour). However, there appear to be plausible, albeit unlikely, scenarios that could cause problematic populations, depending in part on (a) the initial survival fraction and
Experimental and theoretical study of magnetohydrodynamic ship models.
Cébron, David; Viroulet, Sylvain; Vidal, Jérémie; Masson, Jean-Paul; Viroulet, Philippe
2017-01-01
Magnetohydrodynamic (MHD) ships represent a clear demonstration of the Lorentz force in fluids, which explains the number of students practicals or exercises described on the web. However, the related literature is rather specific and no complete comparison between theory and typical small scale experiments is currently available. This work provides, in a self-consistent framework, a detailed presentation of the relevant theoretical equations for small MHD ships and experimental measurements for future benchmarks. Theoretical results of the literature are adapted to these simple battery/magnets powered ships moving on salt water. Comparison between theory and experiments are performed to validate each theoretical step such as the Tafel and the Kohlrausch laws, or the predicted ship speed. A successful agreement is obtained without any adjustable parameter. Finally, based on these results, an optimal design is then deduced from the theory. Therefore this work provides a solid theoretical and experimental ground for small scale MHD ships, by presenting in detail several approximations and how they affect the boat efficiency. Moreover, the theory is general enough to be adapted to other contexts, such as large scale ships or industrial flow measurement techniques.
Experimental and theoretical study of magnetohydrodynamic ship models.
Directory of Open Access Journals (Sweden)
David Cébron
Full Text Available Magnetohydrodynamic (MHD ships represent a clear demonstration of the Lorentz force in fluids, which explains the number of students practicals or exercises described on the web. However, the related literature is rather specific and no complete comparison between theory and typical small scale experiments is currently available. This work provides, in a self-consistent framework, a detailed presentation of the relevant theoretical equations for small MHD ships and experimental measurements for future benchmarks. Theoretical results of the literature are adapted to these simple battery/magnets powered ships moving on salt water. Comparison between theory and experiments are performed to validate each theoretical step such as the Tafel and the Kohlrausch laws, or the predicted ship speed. A successful agreement is obtained without any adjustable parameter. Finally, based on these results, an optimal design is then deduced from the theory. Therefore this work provides a solid theoretical and experimental ground for small scale MHD ships, by presenting in detail several approximations and how they affect the boat efficiency. Moreover, the theory is general enough to be adapted to other contexts, such as large scale ships or industrial flow measurement techniques.
Rohmer, Jeremy
2016-04-01
Predicting the temporal evolution of landslides is typically supported by numerical modelling. Dynamic sensitivity analysis aims at assessing the influence of the landslide properties on the time-dependent predictions (e.g., time series of landslide displacements). Yet two major difficulties arise: 1. Global sensitivity analysis require running the landslide model a high number of times (> 1000), which may become impracticable when the landslide model has a high computation time cost (> several hours); 2. Landslide model outputs are not scalar, but function of time, i.e. they are n-dimensional vectors with n usually ranging from 100 to 1000. In this article, I explore the use of a basis set expansion, such as principal component analysis, to reduce the output dimensionality to a few components, each of them being interpreted as a dominant mode of variation in the overall structure of the temporal evolution. The computationally intensive calculation of the Sobol' indices for each of these components are then achieved through meta-modelling, i.e. by replacing the landslide model by a "costless-to-evaluate" approximation (e.g., a projection pursuit regression model). The methodology combining "basis set expansion - meta-model - Sobol' indices" is then applied to the La Frasse landslide to investigate the dynamic sensitivity analysis of the surface horizontal displacements to the slip surface properties during the pore pressure changes. I show how to extract information on the sensitivity of each main modes of temporal behaviour using a limited number (a few tens) of long running simulations. In particular, I identify the parameters, which trigger the occurrence of a turning point marking a shift between a regime of low values of landslide displacements and one of high values.
Jarzembska, Katarzyna N; Dominiak, Paulina M
2012-01-01
The theoretical databank of aspherical pseudoatoms (UBDB) was recently extended with over 100 new atom types present in RNA, DNA and in some other molecules of great importance in biology and pharmacy. The atom-type definitions were modified and new atom keys added to provide a more precise description of the atomic charge-density distribution. X-H bond lengths were updated according to recent neutron diffraction studies and implemented in the LSDB program as well as used for modelling the appropriate atom types. The UBDB2011 databank was extensively tested. Electrostatic interaction energies calculated on the basis of the databank of aspherical atom models were compared with the corresponding results obtained directly from wavefunctions at the same level of theory (SPDFG/B3LYP/6-31G** and SPDFG/B3LYP/aug-cc-pVDZ). Various small complexes were analysed to cover most of the different interaction types, i.e. adenine-thymine and guanine-cytosine with hydrogen bonding, guanine-adenine with stacking contacts, and a group of neutral and charged species of nucleic acid bases interacting with amino acid side chains. The energy trends are well preserved (R(2) > 0.9); however the energy values differ between the two methods by about 4 kcal mol(-1) (1 kcal mol(-1) = 4.184 kJ mol(-1)) on average. What is noticeable is that the replacement of one basis set by another in a purely quantum chemical approach leads to the same electrostatic energy difference, i.e. of about 4 kcal mol(-1) in magnitude. The present work opens up the possibility of applying the UBDB2011 for macromolecules that contain DNA/RNA fragments. This study shows that on the basis of the UBDB2011 databank electrostatic interaction energies can be estimated and structure refinements carried out. However, some method limitations are apparent.
Determining Student Competency in Field Placements: An Emerging Theoretical Model
Directory of Open Access Journals (Sweden)
Twyla L. Salm
2016-06-01
Full Text Available This paper describes a qualitative case study that explores how twenty-three field advisors, representing three human service professions including education, nursing, and social work, experience the process of assessment with students who are struggling to meet minimum competencies in field placements. Five themes emerged from the analysis of qualitative interviews. The field advisors primary concern was the level of professional competency achieved by practicum students. Related to competency were themes concerned with the field advisor's role in being accountable and protecting the reputation of his/her profession as well as the reputation of the professional program affiliated with the practicum student's professional education. The final theme – teacher-student relationship –emerged from the data, both as a stand-alone and global or umbrella theme. As an umbrella theme, teacher-student relationship permeated each of the other themes as the participants interpreted their experiences of the process of assessment through the mentor relationships. A theoretical model was derived from these findings and the description of the model is presented. Cet article décrit une étude de cas qualitative qui explore comment vingt-trois conseillers de stages, représentant trois professions de services sociaux comprenant l’éducation, les soins infirmiers et le travail social, ont vécu l’expérience du processus d’évaluation avec des étudiants qui ont des difficultés à acquérir les compétences minimales durant les stages. Cinq thèmes ont été identifiés lors de l’analyse des entrevues qualitatives. La préoccupation principale des conseillers de stages était le niveau de compétence professionnelle acquis par les stagiaires. Les thèmes liés à la compétence étaient le rôle des conseillers de stages dans leur responsabilité pour protéger la réputation de leur profession ainsi que la réputation d’un programme professionnel
Kolhatkar, Ashra; Keesey, Andrea; Bluman, Bob; Lynn, Brenna; Wilkinson, Tandi
2017-11-01
The challenges facing emergency medicine (EM) services in Canada reflect the limitations of the entire healthcare system. The emergency department (ED) is uniquely situated in the healthcare system such that shortcomings in hospital- and community-based services are often first revealed there. This is especially true in rural settings, where there are additional site-specific barriers to the provision of EM care. Existing studies look at the factors that influence rural EM physicians in isolation. This study uses a qualitative approach and generates a theoretical model that describes the complex interplay between major factors that influence the experience of rural EM physicians. Eight focus groups were conducted with 39 physicians from rural British Columbia, Canada. Semi-structured focus group protocols were designed to leverage the diversity of the focus groups, which included rural generalists, full-time EM practitioners, physicians from very small and remote communities, locums, international medical graduates, physicians new to practice, and physicians who no longer practice rural EM. Following the principles of grounded theory, interview probes were adjusted iteratively to reflect emerging findings. Transcripts were analysed to identify codes and major themes, which served as the basis for the theoretical model. The theoretical model reveals how the causal conditions (a lack of medical and human resources, and the isolation of rural communities due to topography, distance, and inclement weather) contribute to physicians' common experience of feeling fearful and under-supported at work. Two core phenomena emerge as important needs: supportive professional relationships, and healthcare system adaptability. Contextual factors such as remuneration and continuing medical education funding, and the intervening conditions of physicians' rural exposure during formative years, also have an effect. Physicians create innovative solutions to address the challenges that
An Overview of the Technical Basis of HENRE 2.0 Models
2015-08-01
Journal of Theoretical Biology, 29(383):44–60. Wiernik, G., Shorter, R.G., and Creamer, B., 1962. “The Arrest of Intestinal Epithelial ‘Turnover’ by the...12 3.1.2. Small Intestine Model .......................................................................... 16 3.2 Modeling Combined...16 Figure 8. Morphology of the small intestine epithelium (adapted from Velkey 2009). ............... 18 Figure 9. Conceptual model
Theoretical Modeling of the Surface-Enhanced Raman Optical Activity
Czech Academy of Sciences Publication Activity Database
Novák, Vít; Šebestík, Jaroslav; Bouř, Petr
2012-01-01
Roč. 8, č. 5 (2012), s. 1714-1720 ISSN 1549-9618 R&D Projects: GA ČR GAP208/11/0105; GA MŠk(CZ) LH11033 Institutional research plan: CEZ:AV0Z40550506 Keywords : vibrational spectroscopy * absolute-configuration * silver electrode * spectra * scattering * pyridine Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 5.389, year: 2012
Theoretical Model of Engagement in the Context of Brand Communities
Flávia D\\u2019albergaria Freitas; Victor Manoel Cunha de Almeida
2017-01-01
This essay proposes to refine the concept of consumer engagement in the context of brand communities. A comprehensive review of studies addressing the phenomenon of brand community was made. This paper follows the tradition of Marketing Research and Consumer Behavior, more specifically the perspective of cognitive psychology. The main theoretical foundation of the study is the Social Identity Theory (SIT), also incorporating relevant contributions from the perspective of Consumer Culture Theo...
Rodríguez, J; Clemente, G; Sanjuán, N; Bon, J
2014-01-01
The drying kinetics of thyme was analyzed by considering different conditions: air temperature of between 40°C and 70°C , and air velocity of 1 m/s. A theoretical diffusion model and eight different empirical models were fitted to the experimental data. From the theoretical model application, the effective diffusivity per unit area of the thyme was estimated (between 3.68 × 10(-5) and 2.12 × 10 (-4) s(-1)). The temperature dependence of the effective diffusivity was described by the Arrhenius relationship with activation energy of 49.42 kJ/mol. Eight different empirical models were fitted to the experimental data. Additionally, the dependence of the parameters of each model on the drying temperature was determined, obtaining equations that allow estimating the evolution of the moisture content at any temperature in the established range. Furthermore, artificial neural networks were developed and compared with the theoretical and empirical models using the percentage of the relative errors and the explained variance. The artificial neural networks were found to be more accurate predictors of moisture evolution with VAR ≥ 99.3% and ER ≤ 8.7%.
A new theoretical model for scattering of electrons by molecules. 1
International Nuclear Information System (INIS)
Peixoto, E.M.A.; Mu-tao, L.; Nogueira, J.C.
1975-01-01
A new theoretical model for electron-molecule scattering is suggested. The e-H 2 scattering is studied and the superiority of the new model over the commonly used Independent Atom Model (IAM) is demonstrated. Comparing theoretical and experimental data for 40keV electrons scattered by H 2 utilizing the new model, its validity is proved, while Partial Wave and First Born calculations, employing the Independent Atom Model, strongly deviated from the experiment [pt
A Model for Understanding the Genetic Basis for Disparity in Prostate Cancer Risk
2017-10-01
AWARD NUMBER: W81XWH-15-1-0529 TITLE: A Model for Understanding the Genetic Basis for Disparity in Prostate Cancer Risk PRINCIPAL INVESTIGATOR...reducing this burden to Department of Defense, Washington Headquarters Services, Directorate for Information Operations and Reports (0704-0188), 1215...AND SUBTITLE A Model for Understanding the Genetic Basis for Disparity in Prostate Cancer Risk 5a. CONTRACT NUMBER 5b. GRANT NUMBER W81XWH-15-1
Cheung, Kei Long; Wijnen, Ben; de Vries, Hein
2017-06-23
Tobacco smoking is a worldwide public health problem. In 2015, 26.3% of the Dutch population aged 18 years and older smoked, 74.4% of them daily. More and more people have access to the Internet worldwide; approximately 94% of the Dutch population have online access. Internet-based smoking cessation interventions (online cessation interventions) provide an opportunity to tackle the scourge of tobacco. The goal of this paper was to provide an overview of online cessation interventions in the Netherlands, while exploring their effectivity, cost effectiveness, and theoretical basis. A mixed-methods approach was used to identify Dutch online cessation interventions, using (1) a scientific literature search, (2) a grey literature search, and (3) expert input. For the scientific literature, the Cochrane review was used and updated by two independent researchers (n=651 identified studies), screening titles, abstracts, and then full-text studies between 2013 and 2016 (CENTRAL, MEDLINE, and EMBASE). For the grey literature, the researchers conducted a Google search (n=100 websites), screening for titles and first pages. Including expert input, this resulted in six interventions identified in the scientific literature and 39 interventions via the grey literature. Extracted data included effectiveness, cost effectiveness, theoretical factors, and behavior change techniques used. Overall, many interventions (45 identified) were offered. Of the 45 that we identified, only six that were included in trials provided data on effectiveness. Four of these were shown to be effective and cost effective. In the scientific literature, 83% (5/6) of these interventions included changing attitudes, providing social support, increasing self-efficacy, motivating smokers to make concrete action plans to prepare their attempts to quit and to cope with challenges, supporting identity change and advising on changing routines, coping, and medication use. In all, 50% (3/6) of the interventions
Directory of Open Access Journals (Sweden)
Chaminda Jayasundara
2009-01-01
Full Text Available University library administrators in Sri Lanka have begun to search for alternative ways to satisfy their clientele on the basis of service quality. This article aims at providing a theoretical model to facilitate the identification of service quality attributes and domains that may be used to predict customer satisfaction from a service quality perspective. The effectiveness of existing service quality models such as LibQUAL, SERVQUAL and SERVPREF have been questioned. In that regard, this study developed a theoretical model for academic libraries in Sri Lanka based on the disconfirmation and performance-only paradigms. These perspectives were considered by researchers to be the core mechanism to develop service quality/customer satisfaction models. The attributes and domain identification of service quality was carried out with a stratified sample of 263 participants selected from postgraduate and undergraduate students and academic staff members from the faculties of Arts in four universities in Sri Lanka. The study established that responsiveness, supportiveness, building environment, collection and access, furniture and facilities, technology, Web services and service delivery were quality domains which can be used to predict customer satisfaction. The theoretical model is unique in its domain structure compared to the existing models. The model needs to be statistically tested to make it valid and parsimonious.
Zhumasheva, Anara; Zhumabaeva, Zaida; Sakenov, Janat; Vedilina, Yelena; Zhaxylykova, Nuriya; Sekenova, Balkumis
2016-01-01
The current study focuses on the research topic of creating a theoretical model of development of information competence among students enrolled in elective courses. In order to examine specific features of the theoretical model of development of information competence among students enrolled in elective courses, we performed an analysis of…
Dziedziewicz, Dorota; Karwowski, Maciej
2015-01-01
This paper presents a new theoretical model of creative imagination and its applications in early education. The model sees creative imagination as composed of three inter-related components: vividness of images, their originality, and the level of transformation of imageries. We explore the theoretical and practical consequences of this new…
Theoretical analysis of transcranial Hall-effect stimulation based on passive cable model
International Nuclear Information System (INIS)
Yuan Yi; Li Xiao-Li
2015-01-01
Transcranial Hall-effect stimulation (THS) is a new stimulation method in which an ultrasonic wave in a static magnetic field generates an electric field in an area of interest such as in the brain to modulate neuronal activities. However, the biophysical basis of simulating the neurons remains unknown. To address this problem, we perform a theoretical analysis based on a passive cable model to investigate the THS mechanism of neurons. Nerve tissues are conductive; an ultrasonic wave can move ions embedded in the tissue in a static magnetic field to generate an electric field (due to Lorentz force). In this study, a simulation model for an ultrasonically induced electric field in a static magnetic field is derived. Then, based on the passive cable model, the analytical solution for the voltage distribution in a nerve tissue is determined. The simulation results showthat THS can generate a voltage to stimulate neurons. Because the THS method possesses a higher spatial resolution and a deeper penetration depth, it shows promise as a tool for treating or rehabilitating neuropsychiatric disorders. (paper)
Directory of Open Access Journals (Sweden)
Kahlil Baker
2017-09-01
Full Text Available Academic research on smallholders’ forestland-use decisions is regularly addressed in different streams of literature using different theoretical constructs that are independently incomplete. In this article, we propose a theoretical construct for modelling smallholders’ forestland-use decisions intended to serve in the guidance and operationalization of future models for quantitative analysis. Our construct is inspired by the sub-disciplines of forestry and agricultural economics with a crosscutting theme of how transaction costs drive separability between consumption and production decisions. Our results help explain why exogenous variables proposed in the existing literature are insufficient at explaining smallholders’ forestland-use decisions, and provide theoretical context for endogenizing characteristics of the household, farm and landscape. Smallholders’ forestland-use decisions are best understood in an agricultural context of competing uses for household assets and interdependent consumption and production decisions. Forest production strategies range from natural regeneration to intensive management of the forest resource to co-jointly produce market and non-market values. Due to transaction costs, decision prices are best represented by their shadow as opposed to market prices. Shadow prices are shaped by endogenous smallholder-specific preferences for leisure, non-market values, time, risk, and uncertainty. Our proposed construct is intended to provide a theoretical basis to assist modellers in the selection of variables for quantitative analysis.
On theoretical models of gene expression evolution with random genetic drift and natural selection.
Ogasawara, Osamu; Okubo, Kousaku
2009-11-20
The relative contributions of natural selection and random genetic drift are a major source of debate in the study of gene expression evolution, which is hypothesized to serve as a bridge from molecular to phenotypic evolution. It has been suggested that the conflict between views is caused by the lack of a definite model of the neutral hypothesis, which can describe the long-run behavior of evolutionary change in mRNA abundance. Therefore previous studies have used inadequate analogies with the neutral prediction of other phenomena, such as amino acid or nucleotide sequence evolution, as the null hypothesis of their statistical inference. In this study, we introduced two novel theoretical models, one based on neutral drift and the other assuming natural selection, by focusing on a common property of the distribution of mRNA abundance among a variety of eukaryotic cells, which reflects the result of long-term evolution. Our results demonstrated that (1) our models can reproduce two independently found phenomena simultaneously: the time development of gene expression divergence and Zipf's law of the transcriptome; (2) cytological constraints can be explicitly formulated to describe long-term evolution; (3) the model assuming that natural selection optimized relative mRNA abundance was more consistent with previously published observations than the model of optimized absolute mRNA abundances. The models introduced in this study give a formulation of evolutionary change in the mRNA abundance of each gene as a stochastic process, on the basis of previously published observations. This model provides a foundation for interpreting observed data in studies of gene expression evolution, including identifying an adequate time scale for discriminating the effect of natural selection from that of random genetic drift of selectively neutral variations.
Proposal of a theoretical model for the practical nurse
Directory of Open Access Journals (Sweden)
Dolores Abril Sabater
2010-01-01
Full Text Available AIM: To determine which model of nursing is proposed by care professionals and the reason for their choice. METHOD: cross-sectional, descriptive study design. The main variable: Nursing Models and Theories. As secondary variables were collected: age, gender, years of work experience, nursing model of basic training, and course/s related. We used a self-elaborated, anonymous questionnaire, passed between April - May, 2006. Not random sample.RESULTS: 546 nurses were invited, answered 205. 38 % response rate. Virginia Henderson was the more selected model (33%, however, 42% left the question blank, 12% indicated that they wanted to work under the guidance of a model. They selected a specifically model: Knowledge of the model to their training, standardization in other centers, the characteristics of the model itself and identification with its philosophy. They are not decided by a model by ignorance, lack of time and usefulness. CONCLUSIONS: The model chosen mostly for their daily work was Virginia Henderson model, so that knowledge of a model is the main reason for their election. Professionals who choose not to use the model in their practice realize offers and calling for resources, besides to explain the lack of knowledge on this topic. To advance the nursing profession is necessary that nurse is thought over widely on the abstract concepts of the theory in our context.
[Nursing practice based on theoretical models: a qualitative study of nurses' perception].
Amaducci, Giovanna; Iemmi, Marina; Prandi, Marzia; Saffioti, Angelina; Carpanoni, Marika; Mecugni, Daniela
2013-01-01
Many faculty argue that theory and theorizing are closely related to the clinical practice, that the disciplinary knowledge grows, more relevantly, from the specific care context in which it takes place and, moreover, that knowledge does not proceed only by the application of general principles of the grand theories to specific cases. Every nurse, in fact, have a mental model, of what may or may not be aware, that motivate and substantiate every action and choice of career. The study describes what the nursing theoretical model is; the mental model and the tacit knowledge underlying it. It identifies the explicit theoretical model of the professional group that rapresents nursing partecipants, aspects of continuity with the theoretical model proposed by this degree course in Nursing.. Methods Four focus groups were made which were attended by a total of 22 nurses, rapresentatives of almost every Unit of Reggio Emilia Hospital's. We argue that the theoretical nursing model of each professional group is the result of tacit knowledge, which help to define the personal mental model, and the theoretical model, which explicitly underlying theoretical content learned applied consciously and reverted to / from nursing practice. Reasoning on the use of theory in practice has allowed us to give visibility to a theoretical model explicitly nursing authentically oriented to the needs of the person, in all its complexity in specific contexts.
A graph theoretical perspective of a drug abuse epidemic model
Nyabadza, F.; Mukwembi, S.; Rodrigues, B. G.
2011-05-01
A drug use epidemic can be represented by a finite number of states and transition rules that govern the dynamics of drug use in each discrete time step. This paper investigates the spread of drug use in a community where some users are in treatment and others are not in treatment, citing South Africa as an example. In our analysis, we consider the neighbourhood prevalence of each individual, i.e., the proportion of the individual’s drug user contacts who are not in treatment amongst all of his or her contacts. We introduce parameters α∗, β∗ and γ∗, depending on the neighbourhood prevalence, which govern the spread of drug use. We examine how changes in α∗, β∗ and γ∗ affect the system dynamics. Simulations presented support the theoretical results.
The theoretical foundations for size spectrum models of fish communities
DEFF Research Database (Denmark)
Andersen, Ken Haste; Jacobsen, Nis Sand; Farnsworth, K.D.
2016-01-01
assessment of fisheries. We describe the fundamental concepts in size-based models about food encounter and the bioenergetics budget of individuals. Within the general framework three model types have emerged that differs in their degree of complexity: the food-web, the trait-based and the community model...
Directory of Open Access Journals (Sweden)
Yingwu Zhou
2015-01-01
Full Text Available Sulfate corrosion is one of the most important factors responsible for the performance degradation of concrete materials. In this paper, an accelerated corrosion by a sulfate solution in a dry-wet cycle was introduced to simulate the external sulfate corrosion environment. The deterioration trend of concrete strength and development law of sulfate-induced concrete corrosion depth under sulfate attacks were experimentally studied. The damaged concrete section is simply but reasonably divided into uncorroded and corroded layers and the two layers can be demarcated by the sulfate corrosion depth of concrete. The accelerated corrosion test results indicated that the strength degradation of concrete by sulfate attack had a significant relation with the corrosion depth. Consequently, this paper aims to reveal such relation and thus model the strength degradation law. A large amount of experimental data has finally verified the validity and applicability of the models, and a theoretical basis is thus provided for the strength degradation prediction and the residual life assessment of in-service concrete structures under sulfate attacks.
Theoretical models of magnetic field line merging. I
International Nuclear Information System (INIS)
Vasyliunas, V.M.
1975-01-01
Models of magnetic field line merging that consider processes in a limited region around the magnetic X line, within which the external magnetic fields are roughly uniform and antiparallel, are reviewed. Part I describes the concept of magnetic merging and then considers the models based on a hydromagnetic approach. The models developed by Sweet and Parker, by Petschek, and by Sonnerup and Yeh and Axford are shown to be fundamentally consistent, representing different aspects of the same problem. The model of Sweet and Parker describes the small region around the neutral line where magnetic field diffusion is the dominant process. The inclusion of inertial as well as finite resistivity effects allows an extension of their model to collisionless plasmas. Petschek's model represents a system with a boundary condition of uniform field at the sides; it has been extended and formulated in a mathematically precise manner. The nonsingular model of Sonnerup and of Yeh and Axford has special boundary conditions at the sides producing localized slow mode MHD expansion fans in the external flow; the singular models and the compressible similarity models are physically unrealizable. The maximum merging rate corresponds to flow into the diffusion region of the local Alfven speed, which, however, can be made arbitrarily large by slow mode MHD expansion if suitable boundary condi []ions are present. (auth)
Modeling and Simulation Fundamentals Theoretical Underpinnings and Practical Domains
Sokolowski, John A
2010-01-01
An insightful presentation of the key concepts, paradigms, and applications of modeling and simulation. Modeling and simulation has become an integral part of research and development across many fields of study, having evolved from a tool to a discipline in less than two decades. Modeling and Simulation Fundamentals offers a comprehensive and authoritative treatment of the topic and includes definitions, paradigms, and applications to equip readers with the skills needed to work successfully as developers and users of modeling and simulation. Featuring contributions written by leading experts
Hydrophobic ampersand hydrophilic: Theoretical models of solvation for molecular biophysics
International Nuclear Information System (INIS)
Pratt, L.R.; Tawa, G.J.; Hummer, G.; Garcia, A.E.; Corcelli, S.A.
1996-01-01
Molecular statistical thermodynamic models of hydration for chemistry and biophysics have advanced abruptly in recent years. With liquid water as solvent, salvation phenomena are classified as either hydrophobic or hydrophilic effects. Recent progress in treatment of hydrophilic effects have been motivated by continuum dielectric models interpreted as a modelistic implementation of second order perturbation theory. New results testing that perturbation theory of hydrophilic effects are presented and discussed. Recent progress in treatment of hydrophobic effects has been achieved by applying information theory to discover models of packing effects in dense liquids. The simplest models to which those ideas lead are presented and discussed
A Theoretical Study of Subsurface Drainage Model Simulation of ...
African Journals Online (AJOL)
A three-dimensional variable-density groundwater flow model, the SEAWAT model, was used to assess the influence of subsurface drain spacing, evapotranspiration and irrigation water quality on salt concentration at the base of the root zone, leaching and drainage in salt affected irrigated land. The study was carried out ...
The Interval Market Model in Mathematical Finance : Game Theoretic Methods
Bernhard, P.; Engwerda, J.C.; Roorda, B.; Schumacher, J.M.; Kolokoltsov, V.; Saint-Pierre, P.; Aubin, J.P.
2013-01-01
Toward the late 1990s, several research groups independently began developing new, related theories in mathematical finance. These theories did away with the standard stochastic geometric diffusion “Samuelson” market model (also known as the Black-Scholes model because it is used in that most famous
Nonlinear local electrovascular coupling. I: A theoretical model.
Riera, Jorge J; Wan, Xiaohong; Jimenez, Juan Carlos; Kawashima, Ryuta
2006-11-01
Here we present a detailed biophysical model of how brain electrical and vascular dynamics are generated within a basic cortical unit. The model was obtained from coupling a canonical neuronal mass and an expandable vasculature. In this proposal, we address several aspects related to electroencephalographic and functional magnetic resonance imaging data fusion: (1) the impact of the cerebral architecture (at different physical levels) on the observations; (2) the physiology involved in electrovascular coupling; and (3) energetic considerations to gain a better understanding of how the glucose budget is used during neuronal activity. The model has three components. The first is the canonical neural mass model of three subpopulations of neurons that respond to incoming excitatory synaptic inputs. The generation of the membrane potentials in the somas of these neurons and the electric currents flowing in the neuropil are modeled by this component. The second and third components model the electrovascular coupling and the dynamics of vascular states in an extended balloon approach, respectively. In the first part we describe, in some detail, the biophysical model and establish its face validity using simulations of visually evoked responses under different flickering frequencies and luminous contrasts. In a second part, a recursive optimization algorithm is developed and used to make statistical inferences about this forward/generative model from actual data. Copyright 2006 Wiley-Liss, Inc.
Experimental observations and theoretical models for beam-beam phenomena
International Nuclear Information System (INIS)
Kheifets, S.
1981-03-01
The beam-beam interaction in storage rings exhibits all the characteristics of nonintegrable dynamical systems. Here one finds all kinds of resonances, closed orbits, stable and unstable fixed points, stochastic layers, chaotic behavior, diffusion, etc. The storage ring itself being an expensive device nevertheless while constructed and put into operation presents a good opportunity of experimentally studying the long-time behavior of both conservative (proton machines) and nonconservative (electron machines) dynamical systems - the number of bunch-bunch interactions routinely reaches values of 10 10 -10 11 and could be increased by decreasing the beam current. At the same time the beam-beam interaction puts practical limits for the yield of the storage ring. This phenomenon not only determines the design value of main storage ring parameters (luminosity, space charge parameters, beam current), but also in fact prevents many of the existing storage rings from achieving design parameters. Hence, the problem has great practical importance along with its enormous theoretical interest. A brief overview of the problem is presented
An isotonic partial credit model for ordering subjects on the basis of their sum scores
Ligtvoet, R.
2012-01-01
In practice, the sum of the item scores is often used as a basis for comparing subjects. For items that have more than two ordered score categories, only the partial credit model (PCM) and special cases of this model imply that the subjects are stochastically ordered on the common latent variable.
Use of GERAM as Basis for a Virtual Enterprise Framework Model
DEFF Research Database (Denmark)
Vesterager, Johan; Bernus, Peter; Larsen, Lars B
2001-01-01
In the IMS-project Globeman21, the enterprise reference architecture GERAM was used as basis for creation of a virtual enterprise framework model. The model was used to map different industrial pilot projects, to classify virtual en-terprise concepts, and as underlying structure for a virtual ent...
Rigorous theoretical derivation of lumped models to transmission line systems
International Nuclear Information System (INIS)
Zhao Jixiang
2012-01-01
By virtue of the negative electric parameter concept, i.e. negative lumped resistance, inductance, conductance and capacitance (N-RLGC), the lumped equivalent models of transmission line systems, including the circuit model, two-port π-network and T-network, are given. We start from the N-segment-ladder-like equivalent networks composed distributed parameters, and achieve the input impedance in the form of a continued fraction. Utilizing the continued fraction theory, the expressions of input impedance are obtained under three kinds of extreme cases, i.e. the load impedances are equal to zero, infinity and characteristic impedance, respectively. When the number of segment N is limited to infinity, they are transformed to lumped elements. Comparison between the distributed model and lumped model of transmission lines, the expression of tanh γd, which is the key term in the transmission line equations, are obtained by RLGC, furthermore, according to input admittance, admittance matrix and ABCD matrix of transmission lines, the lumped equivalent circuit models, π-networks and T-networks have been given. The models are verified in the frequency and time domain, respectively, showing that the models are accurate and efficient. (semiconductor integrated circuits)
A theoretical model for gas permeability in a composite membrane
International Nuclear Information System (INIS)
Serrano, D. A
2009-01-01
We present in this work an analytical expression for permeability in a two-layer composite membrane, which was derived assuming the same hypothesis as those of Adzumi model for permeability in a homogeneous membrane. Whereas in Adzumi model permeability shows a linear dependence on the mean pressure, our model for a composite membrane related permeability to pressure through a rather complex expression, which covers the whole range of flow, from molecular-Knudsen to viscous-Poiseuille regimes. The expression obtained for permeability contained information of membrane structural properties as pore size, porosity and thickness of each layer, as well as gas nature and operational conditions. Our two-layer-model expression turns into Adzumi formula when the structure of the layers approach to each other. [es
Theoretical tornado vortex model for nuclear plant design
International Nuclear Information System (INIS)
Sun, C.N.; Barnett, R.O.; Burdette, E.G.
1977-01-01
A simplified tornado vortex model is defined using fluid dynamics theory. Beginning with the Navier-Stokes equations of motion for an incompressible fluid and simpifying in a way consistent with a tornado wind field, develops the well-known cyclostrophic wind equation referred to by Hoecker and another equation which defines the tangential velocity profile. Together, they define a simplified tornado vertex model of which the Rankine and Hoecker vortices are special cases. Practical implications of the results obtained are discussed. (Auth.)
Design theoretic analysis of three system modeling frameworks.
Energy Technology Data Exchange (ETDEWEB)
McDonald, Michael James
2007-05-01
This paper analyzes three simulation architectures from the context of modeling scalability to address System of System (SoS) and Complex System problems. The paper first provides an overview of the SoS problem domain and reviews past work in analyzing model and general system complexity issues. It then identifies and explores the issues of vertical and horizontal integration as well as coupling and hierarchical decomposition as the system characteristics and metrics against which the tools are evaluated. In addition, it applies Nam Suh's Axiomatic Design theory as a construct for understanding coupling and its relationship to system feasibility. Next it describes the application of MATLAB, Swarm, and Umbra (three modeling and simulation approaches) to modeling swarms of Unmanned Flying Vehicle (UAV) agents in relation to the chosen characteristics and metrics. Finally, it draws general conclusions for analyzing model architectures that go beyond those analyzed. In particular, it identifies decomposition along phenomena of interaction and modular system composition as enabling features for modeling large heterogeneous complex systems.
Theoretic models for recommendation and implementation of assistive technology
Directory of Open Access Journals (Sweden)
Ana Cristina de Jesus Alves
2016-07-01
Full Text Available Introduction: The latest international researches seek to understand the factors affecting the successful use of assistive technology devices through studies regarding the assessments systematizing; abandonment of devices; or theoric models that consider the aspects of those devices implementation. In Brazil the researches are focused on developing new technologies and there are still not sufficient studies related to the successful use of devices and ways of assistive technology implementation. Objective: To identify conceptual models used for indication and implementation of assistive technology devices. Method: Literature review. The survey was conducted in six databases: CINAHAL, Eric, GALE, LILACS, MEDLINE e PsycInfo. A critical analysis described by Grant and Booth was used. Results: There are no records of a Brazilian survey and among 29 selected articles, 17 conceptual models used in the area of AT were found; of these, 14 were specific to AT. The results showed that the new conceptual models of TA are under development and the conceptual model “Matching Person and Technology – MPT” was the most mentioned. Conclusion: We can observe that the practices related to TA area in international context shows a correlation with conceptual models, thus, we hope this study might have the capacity to contribute for the propagation of this precepts at national level
A game-theoretical model of private power production
International Nuclear Information System (INIS)
Xing, W.; Wu, F.F.
2001-01-01
Private power production has sprung up all over the world. The build-operate-transfer (BOT) arrangement has emerged as one of the most important options for private power production, especially in developing countries with rapidly growing demand and financial shortages. Based on oligopoly theory, the paper proposes a Stackelberg game model between a BOT investor and an electric utility whereby they can negotiate a long-term energy contract. Asymmetric pricing schemes are taken into account such that a host utility purchases electricity from a BOT company at its ''avoided cost'', and sells its electricity to end users at its ''average cost''. Our Stackelberg game model is transferred into a two-level optimization problem, and then solved by an iterative algorithm. The game model is demonstrated by an illustrative example. (author)
Theoretical models in the development of advertising for food products
DEFF Research Database (Denmark)
Bech-Larsen, Tino; Stacey, Julia
2005-01-01
the advertisement influences the target may serve as creative inspiration and as a common frame of reference for those involved in the development of advertisements. The means-end-chain model says that an advertisement is effective by connecting the product's attributes (means) and the target's personal values...... apples. One proposal, which is based on the meansendchain model, tries to establish a connection between the vitamin and energy content of apples and the personal value: quality of life. The other one is made in the traditional fashion, ie without the use of theoreticalmodels. Its message is that apples...
Path-Goal Models as a Basis for the Design of Organization Reward Systems.
Galbraith, Jay R.
The purpose of this paper has been to argue the usefulness of path-goal models in theoretical research and practical design of organization reward systems. The reasoning is that the policy choices can be easily related to path-goal attitudes which, in turn, are related to behavior. The major policy choices were identified and related to path-goal…
Theoretical Modeling of Mechanical Behavior and Release Properties of Microcapsules
Sagis, L.M.C.
2015-01-01
Microcapsules in food often have a shell with a complex microstructure; the mechanical and structural properties of these shells affect the response of the capsules to deforming forces and the release kinetics of encapsulated components. In this chapter we will discuss a number of models which are
A theoretical and empirical model for soil conservation using ...
African Journals Online (AJOL)
This paper illuminates the practice of indigenous soil conservation among Mamasani farmers in Fars province in Iran. Bos's decision making model was used as a conceptual framework for the study. A qualitative paradigm was used as research methodology. Qualitative techniques were: Mind Mapping, RRA ...
A theoretical Markov chain model for evaluating correctional ...
African Journals Online (AJOL)
In this paper a stochastic method is applied in the study of the long time effect of confinement in a correctional institution on the behaviour of a person with criminal tendencies. The approach used is Markov chain, which uses past history to predict the state of a system in the future. A model is developed for comparing the ...
An Alternative Theoretical Model for Economic Reforms in Africa ...
African Journals Online (AJOL)
This paper offers an alternative model for economic reforms in Africa. It proposes that Africa can still get on the pathway of sustained economic growth if economic reforms can focus on a key variable, namely, the price of non-tradables. Prices of non-tradables are generally less in Africa than in advanced economies, and the ...
Simple Brownian diffusion an introduction to the standard theoretical models
Gillespie, Daniel T
2013-01-01
Brownian diffusion, the motion of large molecules in a sea of very many much smaller molecules, is topical because it is one of the ways in which biologically important molecules move about inside living cells. This book presents the mathematical physics that underlies the four simplest models of Brownian diffusion.
A coordination theoretic model for three level supply chains using ...
Indian Academy of Sciences (India)
the contract renewal time, the supply chain nervousness can be reduced. A pricing model is formulated to address partnership expectations for a fair sharing of savings of the supply chain members. ...... the level of optimality and robustness of a given strategy (Terzi & Cavalieri 2004). Simulation may be used to capture ...
Model United Nations and Deep Learning: Theoretical and Professional Learning
Engel, Susan; Pallas, Josh; Lambert, Sarah
2017-01-01
This article demonstrates that the purposeful subject design, incorporating a Model United Nations (MUN), facilitated deep learning and professional skills attainment in the field of International Relations. Deep learning was promoted in subject design by linking learning objectives to Anderson and Krathwohl's (2001) four levels of knowledge or…
Theoretical models for ultrashort electromagnetic pulse propagation in nonlinear metamaterials
International Nuclear Information System (INIS)
Wen, Shuangchun; Xiang, Yuanjiang; Dai, Xiaoyu; Tang, Zhixiang; Su, Wenhua; Fan, Dianyuan
2007-01-01
A metamaterial (MM) differs from an ordinary optical material mainly in that it has a dispersive magnetic permeability and offers greatly enhanced design freedom to alter the linear and nonlinear properties. This makes it possible for us to control the propagation of ultrashort electromagnetic pulses at will. Here we report on generic features of ultrashort electromagnetic pulse propagation and demonstrate the controllability of both the linear and nonlinear parameters of models for pulse propagation in MMs. First, we derive a generalized system of coupled three-dimensional nonlinear Schroedinger equations (NLSEs) suitable for few-cycle pulse propagation in a MM with both nonlinear electric polarization and nonlinear magnetization. The coupled equations recover previous models for pulse propagation in both ordinary material and a MM under the same conditions. Second, by using the coupled NLSEs in the Drude dispersive model as an example, we identify the respective roles of the dispersive electric permittivity and magnetic permeability in ultrashort pulse propagation and disclose some additional features of pulse propagation in MMs. It is shown that, for linear propagation, the sign and magnitude of space-time focusing can be controlled through adjusting the linear dispersive permittivity and permeability. For nonlinear propagation, the linear dispersive permittivity and permeability are incorporated into the nonlinear magnetization and nonlinear polarization, respectively, resulting in controllable magnetic and electric self-steepening effects and higher-order dispersively nonlinear terms in the propagation models
The mystery of regional unemployment differentials : Theoretical and empirical explanations
Elhorst, JP
2003-01-01
This paper provides an integrated overview of theoretical and empirical explanations used in the applied literature on regional unemployment differentials. On the basis of 41 empirical studies, four different model types covering nine theoretical constructs of regional unemployment determination and
Nonlinear System Identification via Basis Functions Based Time Domain Volterra Model
Directory of Open Access Journals (Sweden)
Yazid Edwar
2014-07-01
Full Text Available This paper proposes basis functions based time domain Volterra model for nonlinear system identification. The Volterra kernels are expanded by using complex exponential basis functions and estimated via genetic algorithm (GA. The accuracy and practicability of the proposed method are then assessed experimentally from a scaled 1:100 model of a prototype truss spar platform. Identification results in time and frequency domain are presented and coherent functions are performed to check the quality of the identification results. It is shown that results between experimental data and proposed method are in good agreement.
A theoretical model for evaluation of the design of a hollow-fiber membrane oxygenator.
Tabesh, Hadi; Amoabediny, Ghassem; Poorkhalil, Ali; Khachab, Ali; Kashefi, Ali; Mottaghy, Khosrow
2012-12-01
Geometric data are fundamental to the design of a contactor. The efficiency of a membrane contactor is mainly defined by its mass-transfer coefficient. However, design modifications also have significant effects on the performance of membrane contactors. In a hollow-fiber membrane oxygenator (HFMO), properties such as priming volume and effective membrane surface area (referred to as design specifications) can be determined. In this study, an extensive theoretical model for calculation of geometric data and configuration properties, and, consequently, optimization of the design of an HFMO, is presented. Calculations were performed for Oxyphan(®) hollow-fiber micro-porous membranes, which are frequently used in current HFMOs because of their high gas exchange performance. The results reveal how to regulate both the transverse and longitudinal pitches of fiber bundles to obtain a lower rand width and a greater number of windings. Such modifications assist optimization of module design and, consequently, substantially increase the efficiency of an HFMO. On the basis of these considerations, three values, called efficiency factors, are proposed for evaluation of the design specifications of an HFMO with regard with its performance characteristics (i.e. oxygen-transfer rate and blood pressure drop). Moreover, the performance characteristics of six different commercial HFMOs were measured experimentally, in vitro, under the same standard conditions. Comparison of calculated efficiency factors reveals Quadrox(®) is the oxygenator with the most efficient design with regard with its performance among the oxygenators tested.
Theoretical analysis of transcranial magneto-acoustical stimulation with Hodgkin–Huxley neuron model
Directory of Open Access Journals (Sweden)
Yi eYuan
2016-04-01
Full Text Available Transcranial magneto-acoustical stimulation (TMAS is a novel stimulation technology in which an ultrasonic wave within a magnetostatic field generates an electric current in an area of interest in the brain to modulate neuronal activities. As a key part of the neural network, neurons transmit information in the nervous system. However, the effect of TMAS on the neuronal firing rhythm remains unknown. To address this problem, we investigated the stimulatory mechanism of TMAS on neurons with a Hodgkin-Huxley neuron model. The simulation results indicate that the magnetostatic field intensity and ultrasonic power can affect the amplitude and interspike interval of neuronal action potential under continuous wave ultrasound. The simulation results also show that the ultrasonic power, duty cycle and repetition frequency can alter the firing rhythm of neural action potential under pulsed ultrasound. This study can help to reveal and explain the biological mechanism of TMAS and to provide a theoretical basis for TMAS in the treatment or rehabilitation of neuropsychiatric disorders.
A Theoretical Modeling of Digital World History: Premises, Paradigm, and Scientific Data Strategy
Directory of Open Access Journals (Sweden)
Xudong Wang
2007-10-01
Full Text Available Digital World History is a new expression of world history (or maybe "a new method for world history expression" and a paradigm of world history description, study, and application by virtual informatization and recovery. It is also a comprehensive systematic study through dynamic marks, integrated description, and retrieval of human society evolution and its causality dependant on the theory and methodology of digitization information. It aims at breaking the limitation of diachronic language attributed to the process of history cognition, summation, and recovery, addressing a possible scheme to fuse historical factors in relation to changing history, dynamically applying a multiplicity of results so that the discipline of world history can meet the needs of the information-equipped society of the 21st century. In this article, the author uses theoretical modelling methods, resulting in a blueprint of the quality issue, namely the Digital World History premise, and a paradigm for setting the foundation and scientific data strategy as a basis for its necessity.
Liang, Fuyou; Guan, Debao; Alastruey, Jordi
2018-03-01
Hypertension is a well-documented predictive factor for cardiovascular events. Clinical studies have extensively demonstrated the differential hemodynamic consequences of various antihypertensive drugs, but failed to clearly elucidate the underlying mechanisms due to the difficulty in performing a quantitative deterministic analysis based on clinical data that carry confounding information stemming from interpatient differences and the nonlinearity of cardiovascular hemodynamics. In the present study, a multiscale model of the cardiovascular system was developed to quantitatively investigate the relationships between hemodynamic variables and cardiovascular properties under hypertensive conditions, aiming to establish a theoretical basis for assisting in the interpretation of clinical observations or optimization of therapy. Results demonstrated that heart period, central arterial stiffness, and arteriolar radius were the major determinant factors for blood pressures and flow pulsatility indices both in large arteries and in the microcirculation. These factors differed in the degree and the way in which they affect hemodynamic variables due to their differential effects on wave reflections in the vascular system. In particular, it was found that the hemodynamic effects of varying arteriolar radius were considerably influenced by the state of central arterial stiffness, and vice versa, which implied the potential of optimizing antihypertensive treatment by selecting proper drugs based on patient-specific cardiovascular conditions. When analyzed in relation to clinical observations, the simulated results provided mechanistic explanations for the beneficial pressure-lowering effects of vasodilators as compared to β-blockers, and highlighted the significance of monitoring and normalizing arterial stiffness in the treatment of hypertension.
Theoretical model of the early phases of an underground explosion
International Nuclear Information System (INIS)
Cameron, I.G.; Scorgie, G.C.
1970-01-01
Introduction In the early phases of the intense underground explosions contemplated in peaceful applications the rock near the explosive exhibits fluid behaviour; at great distances its behaviour can usefully be investigated in terms of linear elasticity; and at intermediate distances we think of a solid exhibiting various inelastic effects including cracking and tensile fracture. The present paper outlines a mathematical model that attempts to include in some degree the main features of this range of behaviour. A more detailed treatment than is given here, and its relationship to the work of others, is given in a paper by the authors. A computer program ATHENE has been written based on this model and its use is illustrated by examining some aspects of two types of explosions. One is a chemical explosion which eventually formed a crater and the other a nuclear explosion which remained wholly contained
Accelerator simulation and theoretical modelling of radiation effects (SMoRE)
2018-01-01
This publication summarizes the findings and conclusions of the IAEA coordinated research project (CRP) on accelerator simulation and theoretical modelling of radiation effects, aimed at supporting Member States in the development of advanced radiation-resistant structural materials for implementation in innovative nuclear systems. This aim can be achieved through enhancement of both experimental neutron-emulation capabilities of ion accelerators and improvement of the predictive efficiency of theoretical models and computer codes. This dual approach is challenging but necessary, because outputs of accelerator simulation experiments need adequate theoretical interpretation, and theoretical models and codes need high dose experimental data for their verification. Both ion irradiation investigations and computer modelling have been the specific subjects of the CRP, and the results of these studies are presented in this publication which also includes state-ofthe- art reviews of four major aspects of the project...
International Nuclear Information System (INIS)
Balagyra, V.S.; Ryabka, P.M.
1999-01-01
For measuring the charged particle energy calculations of mean square angles of electron beam multiple Coulomb scattering at output combined accelerator target were undertaken according to seven theoretical models. Mollier method showed the best agreement with experiments
Theoretical study (Lagrangian modeling) of turbulent particulate dispersion
Berlemont, A.; Grancher, M. S.; Desjonqueres, P.
A study aimed at improving the prediction and knowledge of two phase phenomena in a turbomachine is presented. A code to three dimensionally simulate particle dispersion, taking account of turbulent droplet evaporation, and which can be easily integrated into the DIAMANT code, is developed. Lagrangian modeling of particle dispersion is used. The influence of turbulence on evaporation appears to be non-negligible and must therefore be taken into account in droplet turbulent transfer problems.
Theoretical modeling of infrared spectra of twinned lead zirconate
Czech Academy of Sciences Publication Activity Database
Dočekalová, Zuzana; Pasciak, Marek; Hlinka, Jiří
2017-01-01
Roč. 90, č. 1 (2017), s. 17-23 ISSN 0141-1594 R&D Projects: GA ČR GA15-04121S Institutional support: RVO:68378271 Keywords : domains * IR spectroscopy * dielectric permittivity * lead zirconate * shell model * Born effective charge Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 1.060, year: 2016
Hybrid empirical--theoretical approach to modeling uranium adsorption
Energy Technology Data Exchange (ETDEWEB)
Hull, Larry C.; Grossman, Christopher; Fjeld, Robert A.; Coates, John T.; Elzerman, Alan W
2004-05-01
An estimated 330 metric tons of U are buried in the radioactive waste Subsurface Disposal Area (SDA) at the Idaho National Engineering and Environmental Laboratory (INEEL). An assessment of U transport parameters is being performed to decrease the uncertainty in risk and dose predictions derived from computer simulations of U fate and transport to the underlying Snake River Plain Aquifer. Uranium adsorption isotherms were measured for 14 sediment samples collected from sedimentary interbeds underlying the SDA. The adsorption data were fit with a Freundlich isotherm. The Freundlich n parameter is statistically identical for all 14 sediment samples and the Freundlich K{sub f} parameter is correlated to sediment surface area (r{sup 2}=0.80). These findings suggest an efficient approach to material characterization and implementation of a spatially variable reactive transport model that requires only the measurement of sediment surface area. To expand the potential applicability of the measured isotherms, a model is derived from the empirical observations by incorporating concepts from surface complexation theory to account for the effects of solution chemistry. The resulting model is then used to predict the range of adsorption conditions to be expected in the vadose zone at the SDA based on the range in measured pore water chemistry. Adsorption in the deep vadose zone is predicted to be stronger than in near-surface sediments because the total dissolved carbonate decreases with depth.
Testing theoretical models of subdwarf B stars using multicolor photometry
Reed, Mike; Baran, Andrzej; Ostensen, Roy; O'Toole, Simon
2012-08-01
Pulsating stars allow a direct investigation of their structure and evolutionary history from the evaluation of pulsation modes. However, the observed pulsation frequencies must first be identified with spherical harmonics (modes). For subdwarfs B (sdB) stars, such identifications using white light photometry currently have significant limitations. We intend to use multicolor photometry to identify pulsation modes and constrain structure models. We propose to observe the pulsating sdB star PG0154+182 (BI Ari) with our multicolor instrument GT Cam. Our observations will be compared with perturbative atmospheric models (BRUCE/KYLIE) to identify the pulsation modes. This is part of our NSF grant to obtain seismic tools to test structure and evolution models; constraining stellar parameters including total mass, envelope mass, internal composition discontinuities and internal rotation. During winter/spring 2012, we were allocated three runs on the 2.1 m to collect multicolor data on other promising pulsating subdwarf B stars as part of this work. Those runs were very successful, prompting our continued proposals. In addition, we will obtain 3-color data using MAIA on the Mercator Telescope (using guaranteed institutional time).
Modeling postpartum depression in rats: theoretic and methodological issues
Ming, LI; Shinn-Yi, CHOU
2016-01-01
The postpartum period is when a host of changes occur at molecular, cellular, physiological and behavioral levels to prepare female humans for the challenge of maternity. Alteration or prevention of these normal adaptions is thought to contribute to disruptions of emotion regulation, motivation and cognitive abilities that underlie postpartum mental disorders, such as postpartum depression. Despite the high incidence of this disorder, and the detrimental consequences for both mother and child, its etiology and related neurobiological mechanisms remain poorly understood, partially due to the lack of appropriate animal models. In recent decades, there have been a number of attempts to model postpartum depression disorder in rats. In the present review, we first describe clinical symptoms of postpartum depression and discuss known risk factors, including both genetic and environmental factors. Thereafter, we discuss various rat models that have been developed to capture various aspects of this disorder and knowledge gained from such attempts. In doing so, we focus on the theories behind each attempt and the methods used to achieve their goals. Finally, we point out several understudied areas in this field and make suggestions for future directions. PMID:27469254
Hybrid empirical--theoretical approach to modeling uranium adsorption
International Nuclear Information System (INIS)
Hull, Larry C.; Grossman, Christopher; Fjeld, Robert A.; Coates, John T.; Elzerman, Alan W.
2004-01-01
An estimated 330 metric tons of U are buried in the radioactive waste Subsurface Disposal Area (SDA) at the Idaho National Engineering and Environmental Laboratory (INEEL). An assessment of U transport parameters is being performed to decrease the uncertainty in risk and dose predictions derived from computer simulations of U fate and transport to the underlying Snake River Plain Aquifer. Uranium adsorption isotherms were measured for 14 sediment samples collected from sedimentary interbeds underlying the SDA. The adsorption data were fit with a Freundlich isotherm. The Freundlich n parameter is statistically identical for all 14 sediment samples and the Freundlich K f parameter is correlated to sediment surface area (r 2 =0.80). These findings suggest an efficient approach to material characterization and implementation of a spatially variable reactive transport model that requires only the measurement of sediment surface area. To expand the potential applicability of the measured isotherms, a model is derived from the empirical observations by incorporating concepts from surface complexation theory to account for the effects of solution chemistry. The resulting model is then used to predict the range of adsorption conditions to be expected in the vadose zone at the SDA based on the range in measured pore water chemistry. Adsorption in the deep vadose zone is predicted to be stronger than in near-surface sediments because the total dissolved carbonate decreases with depth
A Theoretical Model for the Associative Nature of Conference Participation.
Directory of Open Access Journals (Sweden)
Jelena Smiljanić
Full Text Available Participation in conferences is an important part of every scientific career. Conferences provide an opportunity for a fast dissemination of latest results, discussion and exchange of ideas, and broadening of scientists' collaboration network. The decision to participate in a conference depends on several factors like the location, cost, popularity of keynote speakers, and the scientist's association with the community. Here we discuss and formulate the problem of discovering how a scientist's previous participation affects her/his future participations in the same conference series. We develop a stochastic model to examine scientists' participation patterns in conferences and compare our model with data from six conferences across various scientific fields and communities. Our model shows that the probability for a scientist to participate in a given conference series strongly depends on the balance between the number of participations and non-participations during his/her early connections with the community. An active participation in a conference series strengthens the scientist's association with that particular conference community and thus increases the probability of future participations.
A Bayesian spatial model for neuroimaging data based on biologically informed basis functions.
Huertas, Ismael; Oldehinkel, Marianne; van Oort, Erik S B; Garcia-Solis, David; Mir, Pablo; Beckmann, Christian F; Marquand, Andre F
2017-11-01
The dominant approach to neuroimaging data analysis employs the voxel as the unit of computation. While convenient, voxels lack biological meaning and their size is arbitrarily determined by the resolution of the image. Here, we propose a multivariate spatial model in which neuroimaging data are characterised as a linearly weighted combination of multiscale basis functions which map onto underlying brain nuclei or networks or nuclei. In this model, the elementary building blocks are derived to reflect the functional anatomy of the brain during the resting state. This model is estimated using a Bayesian framework which accurately quantifies uncertainty and automatically finds the most accurate and parsimonious combination of basis functions describing the data. We demonstrate the utility of this framework by predicting quantitative SPECT images of striatal dopamine function and we compare a variety of basis sets including generic isotropic functions, anatomical representations of the striatum derived from structural MRI, and two different soft functional parcellations of the striatum derived from resting-state fMRI (rfMRI). We found that a combination of ∼50 multiscale functional basis functions accurately represented the striatal dopamine activity, and that functional basis functions derived from an advanced parcellation technique known as Instantaneous Connectivity Parcellation (ICP) provided the most parsimonious models of dopamine function. Importantly, functional basis functions derived from resting fMRI were more accurate than both structural and generic basis sets in representing dopamine function in the striatum for a fixed model order. We demonstrate the translational validity of our framework by constructing classification models for discriminating parkinsonian disorders and their subtypes. Here, we show that ICP approach is the only basis set that performs well across all comparisons and performs better overall than the classical voxel-based approach
Theoretical model of CR Forbush-decrease and precursors effects
Lev, Dorman
galaxy) in the heliosphere are determined by their interactions with magnetic fields frozen in the solar wind and in coronal mass ejections (CME), which are accompanied by interplanetary shock waves (producing big magnetic storms during their interactions with the Earth’s magnetosphere). The most difficult problem in monitoring and forecasting the modulation of galactic CR in the heliosphere is that the CR intensity in some 4D space-time point is determined not by the level of solar activity at the time of observations and electro-magnetic conditions in this 4D-point, but rather by electromagnetic conditions in the whole heliosphere. These conditions in the whole heliosphere are determined by the development of solar activity over the course of many months before the time-point of observations. This is the main cause of the so-called hysteresis phenomenon in connection with galactic CR - solar activity. On the other hand, detailed investigations of this phenomenon give the important possibility to estimate conditions in and the dimension of the heliosphere. To solve the problem described above of CR modulation in the heliosphere, we considered as the first step the behavior of high energy particles (more than several GeV, for which the diffusion time of propagation in the heliosphere is very small in compared to the characteristic time of modulation), on the basis of neutron monitor data in the frame of convection diffusion theory, then taking into account drift effects. For low energy galactic CR detected on satellites and space probes, we also need to take into account the additional time lag caused by diffusion in the heliosphere. We then consider the problem of CR modulation forecasting for several months and years ahead, which gives the possibility to forecast some part of the global climate change caused by CR.
2015-01-01
among exposed teens . Of the exposed group, 2.5 percent reported having made a (first) suicide attempt during the 18 months of follow-up compared...Gatekeeper Training for Suicide Prevention A Theoretical Model and Review of the Empirical Literature Crystal Burnette, Rajeev Ramchand, Lynsay...REPORT TYPE 3. DATES COVERED 00-00-2015 to 00-00-2015 4. TITLE AND SUBTITLE Gatekeeper Training for Suicide Prevention: A Theoretical Model and
NOOP: A Domain-Theoretic Model of Nominally-Typed OOP
AbdelGawad, Moez; Cartwright, Robert
2018-01-01
The majority of industrial-strength object-oriented (OO) software is written using nominally-typed OO programming languages. Extant domain-theoretic models of OOP developed to analyze OO type systems miss, however, a crucial feature of these mainstream OO languages: nominality. This paper presents the construction of NOOP as the first domain-theoretic model of OOP that includes full class/type names information found in nominally-typed OOP. Inclusion of nominal information in objects of NOOP ...
4. Valorizations of Theoretical Models of Giftedness and Talent in Defining of Artistic Talent
Anghel Ionica Ona
2016-01-01
Artistic talent has been defined in various contexts and registers a variety of meanings, more or less operational. From the perspective of pedagogical intervention, it is imperative understanding artistic talent trough the theoretical models of giftedness and talent. So, the aim of the study is to realize a review of the most popular of the theoretical models of giftedness and talent, with identification of the place of artistic talent and the new meanings that artistic talent has in each on...
Measures of metacognition on signal-detection theoretic models.
Barrett, Adam B; Dienes, Zoltan; Seth, Anil K
2013-12-01
Analyzing metacognition, specifically knowledge of accuracy of internal perceptual, memorial, or other knowledge states, is vital for many strands of psychology, including determining the accuracy of feelings of knowing and discriminating conscious from unconscious cognition. Quantifying metacognitive sensitivity is however more challenging than quantifying basic stimulus sensitivity. Under popular signal-detection theory (SDT) models for stimulus classification tasks, approaches based on Type II receiver-operating characteristic (ROC) curves or Type II d-prime risk confounding metacognition with response biases in either the Type I (classification) or Type II (metacognitive) tasks. A new approach introduces meta-d': The Type I d-prime that would have led to the observed Type II data had the subject used all the Type I information. Here, we (a) further establish the inconsistency of the Type II d-prime and ROC approaches with new explicit analyses of the standard SDT model and (b) analyze, for the first time, the behavior of meta-d' under nontrivial scenarios, such as when metacognitive judgments utilize enhanced or degraded versions of the Type I evidence. Analytically, meta-d' values typically reflect the underlying model well and are stable under changes in decision criteria; however, in relatively extreme cases, meta-d' can become unstable. We explore bias and variance of in-sample measurements of meta-d' and supply MATLAB code for estimation in general cases. Our results support meta-d' as a useful measure of metacognition and provide rigorous methodology for its application. Our recommendations are useful for any researchers interested in assessing metacognitive accuracy. PsycINFO Database Record (c) 2014 APA, all rights reserved.
Theoretical modeling of the absorption spectrum of aqueous riboflavin
Zanetti-Polzi, Laura; Aschi, Massimiliano; Daidone, Isabella; Amadei, Andrea
2017-02-01
In this study we report the modeling of the absorption spectrum of riboflavin in water using a hybrid quantum/classical mechanical approach, the MD-PMM methodology. By means of MD-PMM calculations, with which the effect of riboflavin internal motions and of solvent interactions on the spectroscopic properties can be explicitly taken into account, we obtain an absorption spectrum in very good agreement with the experimental spectrum. In particular, the calculated peak maxima show a consistent improvement with respect to previous computational approaches. Moreover, the calculations show that the interaction with the environment may cause a relevant recombination of the gas-phase electronic states.
Testing theoretical models of magnetic damping using an air track
Vidaurre, Ana; Riera, Jaime; Monsoriu, Juan A.; Gimenez, Marcos H.
2007-01-01
Magnetic braking is a long-established application of Lenz's law. A rigorous analysis of the laws governing this problem involves solving Maxwell's equations in a time-dependent situation. Approximate models have been developed to describe different experiences related to this phenomenon. In this paper we present a new method for the analysis of the magnetic braking using a magnet fixed to the glider of an air track. The forces acting on the glider, a result of the eddy currents, can be easil...
A theoretical study of a nickel SPND using Warren's model
International Nuclear Information System (INIS)
Mahant, A.K.; Rao, P.S.; Misra, S.C.
1998-01-01
Various parameters for a nickel SPND viz. neutron and gamma sensitivity, their dependence on detector dimensions, effect of activity build up during irradiation in the reactor on neutron sensitivity and burn up have been calculated using an analytical model by Warren and Shah. The results show that the main component of neutron sensitivity is due to neutron-induced capture gamma rays (99.93%). Delayed β signal is negligible and signal due to external gamma rays constitute about 0.06%. Low gamma sensitivity to external gamma rays, negligible activity buildup and low burn up rate make it a very promising prompt SPND for power reactors. (orig.)
Polarimetric Signatures of Sea Ice. Part 1; Theoretical Model
Nghiem, S. V.; Kwok, R.; Yueh, S. H.; Drinkwater, M. R.
1995-01-01
Physical, structural, and electromagnetic properties and interrelating processes in sea ice are used to develop a composite model for polarimetric backscattering signatures of sea ice. Physical properties of sea ice constituents such as ice, brine, air, and salt are presented in terms of their effects on electromagnetic wave interactions. Sea ice structure and geometry of scatterers are related to wave propagation, attenuation, and scattering. Temperature and salinity, which are determining factors for the thermodynamic phase distribution in sea ice, are consistently used to derive both effective permittivities and polarimetric scattering coefficients. Polarimetric signatures of sea ice depend on crystal sizes and brine volumes, which are affected by ice growth rates. Desalination by brine expulsion, drainage, or other mechanisms modifies wave penetration and scattering. Sea ice signatures are further complicated by surface conditions such as rough interfaces, hummocks, snow cover, brine skim, or slush layer. Based on the same set of geophysical parameters characterizing sea ice, a composite model is developed to calculate effective permittivities and backscattering covariance matrices at microwave frequencies for interpretation of sea ice polarimetric signatures.
Polarimetric signatures of sea ice. 1: Theoretical model
Nghiem, S. V.; Kwok, R.; Yueh, S. H.; Drinkwater, M. R.
1995-01-01
Physical, structral, and electromagnetic properties and interrelating processes in sea ice are used to develop a composite model for polarimetric backscattering signatures of sea ice. Physical properties of sea ice constituents such as ice, brine, air, and salt are presented in terms of their effects on electromagnetic wave interactions. Sea ice structure and geometry of scatterers are related to wave propagation, attenuation, and scattering. Temperature and salinity, which are determining factors for the thermodynamic phase distribution in sea ice, are consistently used to derive both effective permittivities and polarimetric scattering coefficients. Polarmetric signatures of sea ice depend on crystal sizes and brine volumes, which are affected by ice growth rates. Desalination by brine expulsion, drainage, or other mechanisms modifies wave penetration and scattering. Sea ice signatures are further complicated by surface conditions such as rough interfaces, hummocks, snow cover, brine skim, or slush layer. Based on the same set of geophysical parameters characterizing sea ice, a composite model is developed to calculate effective permittivities and backscattering covariance matrices at microwave frequencies to interpretation of sea ice polarimetric signatures.
Akhmetova, Daniya Z.; Chelnokova, Tatyana A.; Morozova, Ilona G.
2017-01-01
Article is devoted to the scientific heritage of educators and psychologists of Russia in the first quarter of the twentieth century. The aim of the research is the identification of the most significant ideas of P. P. Blonsky, L. S. Vygotsky, V. P. Kacshenko, S. T Shatsky which based the theoretical and methodological basis of inclusive…
A theoretical quantitative model for evolution of cancer chemotherapy resistance
Directory of Open Access Journals (Sweden)
Gatenby Robert A
2010-04-01
Full Text Available Abstract Background Disseminated cancer remains a nearly uniformly fatal disease. While a number of effective chemotherapies are available, tumors inevitably evolve resistance to these drugs ultimately resulting in treatment failure and cancer progression. Causes for chemotherapy failure in cancer treatment reside in multiple levels: poor vascularization, hypoxia, intratumoral high interstitial fluid pressure, and phenotypic resistance to drug-induced toxicity through upregulated xenobiotic metabolism or DNA repair mechanisms and silencing of apoptotic pathways. We propose that in order to understand the evolutionary dynamics that allow tumors to develop chemoresistance, a comprehensive quantitative model must be used to describe the interactions of cell resistance mechanisms and tumor microenvironment during chemotherapy. Ultimately, the purpose of this model is to identify the best strategies to treat different types of tumor (tumor microenvironment, genetic/phenotypic tumor heterogeneity, tumor growth rate, etc.. We predict that the most promising strategies are those that are both cytotoxic and apply a selective pressure for a phenotype that is less fit than that of the original cancer population. This strategy, known as double bind, is different from the selection process imposed by standard chemotherapy, which tends to produce a resistant population that simply upregulates xenobiotic metabolism. In order to achieve this goal we propose to simulate different tumor progression and therapy strategies (chemotherapy and glucose restriction targeting stabilization of tumor size and minimization of chemoresistance. Results This work confirms the prediction of previous mathematical models and simulations that suggested that administration of chemotherapy with the goal of tumor stabilization instead of eradication would yield better results (longer subject survival than the use of maximum tolerated doses. Our simulations also indicate that the
Theoretical modelling of hot gas ingestion through turbine rim seals
Directory of Open Access Journals (Sweden)
J. Michael Owen
2012-12-01
The nozzle guide vanes create three-dimensional (3D variations in the distribution of pressure in the mainstream annulus and the turbine blades create unsteady effects. Computational fluid dynamics (CFD is both time-consuming and expensive for these 3D unsteady flows, and engine designers tend to use correlations or simple models to predict ingress. This paper describes the application of simple ‘orifice models’, the analytical solutions of which can be used to calculate the sealing effectiveness of turbine rim seals. The solutions agree well with available data for externally-induced ingress, where the effects of rotation are negligible, for rotationally-induced ingress, where the effects of the external flow are small, and for combined ingress, where the effects of both external flow and rotation are significant.
A Theoretical Design for Learning Model Addressing the Networked Society
DEFF Research Database (Denmark)
Nielsen, Janni; Levinsen, Karin Tweddell; Sørensen, Birgitte Holm
2010-01-01
The transition from the industrial to the networked society produces contradictions that challenges the educational system and force it to adapt to new conditions. In a Danish virtual Master in Information and Communication Technologies and Learning (MIL) these contradictions appear as a field....... The context for the experiment is MIL's course on Interaction Design. The orchestration is operationalized as a 4-hour script that builds on classic role-play designed as an open ended explorative task. The script of the teams' tasks is designed to facilitate the teams' ongoing negotiation and structuring...... which enables students to develop Networked Society competencies and maintain progression in the learning process also during the online periods. Additionally we suggest that our model contributes to the innovation of a networked society's design for learning....
Theoretical model of fast electron emission from surfaces
Energy Technology Data Exchange (ETDEWEB)
Reinhold, C.; Burgdoerfer, J. [Univ. of Tennessee, Knoxville, TN (United States)]|[Oak Ridge National Laboratory, TN (United States)
1993-05-01
Electron emission in glancing-angle ion-surface collisions has become a focus of ion-surface interactions. Electron spectra can provide detailed information on the above surface neutralization dynamics of multiply charged ions, the electronic structure of the surface (surface density of states), and the long-ranged image interactions near the surface. Recent experiments have found that the convoy peak, well known from ion-atom and ion-solid collisions, is dramatically altered. The peak is broadened and shifted in energy which has been attributed to dynamical image interactions. We present a microscopic model for the emission of fast electrons in glancing-angle surface collisions. A classical trajectory Monte Carlo approach is utilized to calculate the evolution of electrons in the presence of their self image, the projectile Coulomb field and the image potential induced by the projectile. The excitation of collective surface modes is also incorporated.
A data-driven approach to local gravity field modelling using spherical radial basis functions
Klees, R.; Tenzer, R.; Prutkin, I.; Wittwer, T.
2008-01-01
We propose a methodology for local gravity field modelling from gravity data using spherical radial basis functions. The methodology comprises two steps: in step 1, gravity data (gravity anomalies and/or gravity disturbances) are used to estimate the disturbing potential using least-squares
An operator basis for the Standard Model with an added scalar singlet
Energy Technology Data Exchange (ETDEWEB)
Gripaios, Ben [Cavendish Laboratory, J.J. Thomson Avenue, Cambridge (United Kingdom); Sutherland, Dave [Cavendish Laboratory, J.J. Thomson Avenue, Cambridge (United Kingdom); Kavli Institute for Theoretical Physics, UCSB Kohn Hall, Santa Barbara CA (United States)
2016-08-17
Motivated by the possible di-gamma resonance at 750 GeV, we present a basis of effective operators for the Standard Model plus a scalar singlet at dimensions 5, 6, and 7. We point out that an earlier list at dimensions 5 and 6 contains two redundant operators at dimension 5.
VALIDATION OF THEORETICAL MODEL FOR DECISION MAKING ABOUT E-LEARNING IMPLEMENTATION
Directory of Open Access Journals (Sweden)
Nina Begičević
2006-12-01
Full Text Available In the paper the possibility to use mathematical models and statistical techniques in strategic planning and decision making about e-learning is presented. Strategic planning and decision making has been covered as consisting of four phases: (1 intelligence, (2 design, (3 choice and (4 implementation. Each of the phases will be described in this paper, but the accent will be put on the statistical evaluation of the results of the questionnaire which was based on the developed theoretical model for decision making about e-learning implementation in the higher education sector. In general, the main objectives of this paper are: (1 validation of the first theoretical model for decision making about e-learning implementation in the higher education sector, by means of factor analysis and (2 reduction of a large number of variables to a smaller number of factors, i.e. designing the improved theoretical model, for modelling purposes (developing AHP & ANP models.
Description of group-theoretical model of developed turbulence
International Nuclear Information System (INIS)
Saveliev, V L; Gorokhovski, M A
2008-01-01
We propose to associate the phenomenon of stationary turbulence with the special self-similar solutions of the Euler equations. These solutions represent the linear superposition of eigenfields of spatial symmetry subgroup generators and imply their dependence on time through the parameter of the symmetry transformation only. From this model, it follows that for developed turbulent process, changing the scale of averaging (filtering) of the velocity field is equivalent to composition of scaling, translation and rotation transformations. We call this property a renormalization-group invariance of filtered turbulent fields. The renormalization group invariance provides an opportunity to transform the averaged Navier-Stokes equation over a small scale (inner threshold of the turbulence) to larger scales by simple scaling. From the methodological point of view, it is significant to note that the turbulent viscosity term appeared not as a result of averaging of the nonlinear term in the Navier-Stokes equation, but from the molecular viscosity term with the help of renormalization group transformation.
Description of group-theoretical model of developed turbulence
Energy Technology Data Exchange (ETDEWEB)
Saveliev, V L [Institute of Ionosphere, Almaty 050020 (Kazakhstan); Gorokhovski, M A [Laboratoire de Mecanique des Fluides et Acoustique, Ecole Centrale de Lyon, 36, Avenue Guy de Collongues, F69134 Ecully-Cedex (France)], E-mail: saveliev@topmail.kz, E-mail: mikhael.gorokhovski@ec-lyon.fr
2008-12-15
We propose to associate the phenomenon of stationary turbulence with the special self-similar solutions of the Euler equations. These solutions represent the linear superposition of eigenfields of spatial symmetry subgroup generators and imply their dependence on time through the parameter of the symmetry transformation only. From this model, it follows that for developed turbulent process, changing the scale of averaging (filtering) of the velocity field is equivalent to composition of scaling, translation and rotation transformations. We call this property a renormalization-group invariance of filtered turbulent fields. The renormalization group invariance provides an opportunity to transform the averaged Navier-Stokes equation over a small scale (inner threshold of the turbulence) to larger scales by simple scaling. From the methodological point of view, it is significant to note that the turbulent viscosity term appeared not as a result of averaging of the nonlinear term in the Navier-Stokes equation, but from the molecular viscosity term with the help of renormalization group transformation.
Model's sparse representation based on reduced mixed GMsFE basis methods
Energy Technology Data Exchange (ETDEWEB)
Jiang, Lijian, E-mail: ljjiang@hnu.edu.cn [Institute of Mathematics, Hunan University, Changsha 410082 (China); Li, Qiuqi, E-mail: qiuqili@hnu.edu.cn [College of Mathematics and Econometrics, Hunan University, Changsha 410082 (China)
2017-06-01
In this paper, we propose a model's sparse representation based on reduced mixed generalized multiscale finite element (GMsFE) basis methods for elliptic PDEs with random inputs. A typical application for the elliptic PDEs is the flow in heterogeneous random porous media. Mixed generalized multiscale finite element method (GMsFEM) is one of the accurate and efficient approaches to solve the flow problem in a coarse grid and obtain the velocity with local mass conservation. When the inputs of the PDEs are parameterized by the random variables, the GMsFE basis functions usually depend on the random parameters. This leads to a large number degree of freedoms for the mixed GMsFEM and substantially impacts on the computation efficiency. In order to overcome the difficulty, we develop reduced mixed GMsFE basis methods such that the multiscale basis functions are independent of the random parameters and span a low-dimensional space. To this end, a greedy algorithm is used to find a set of optimal samples from a training set scattered in the parameter space. Reduced mixed GMsFE basis functions are constructed based on the optimal samples using two optimal sampling strategies: basis-oriented cross-validation and proper orthogonal decomposition. Although the dimension of the space spanned by the reduced mixed GMsFE basis functions is much smaller than the dimension of the original full order model, the online computation still depends on the number of coarse degree of freedoms. To significantly improve the online computation, we integrate the reduced mixed GMsFE basis methods with sparse tensor approximation and obtain a sparse representation for the model's outputs. The sparse representation is very efficient for evaluating the model's outputs for many instances of parameters. To illustrate the efficacy of the proposed methods, we present a few numerical examples for elliptic PDEs with multiscale and random inputs. In particular, a two-phase flow model in
Model's sparse representation based on reduced mixed GMsFE basis methods
International Nuclear Information System (INIS)
Jiang, Lijian; Li, Qiuqi
2017-01-01
In this paper, we propose a model's sparse representation based on reduced mixed generalized multiscale finite element (GMsFE) basis methods for elliptic PDEs with random inputs. A typical application for the elliptic PDEs is the flow in heterogeneous random porous media. Mixed generalized multiscale finite element method (GMsFEM) is one of the accurate and efficient approaches to solve the flow problem in a coarse grid and obtain the velocity with local mass conservation. When the inputs of the PDEs are parameterized by the random variables, the GMsFE basis functions usually depend on the random parameters. This leads to a large number degree of freedoms for the mixed GMsFEM and substantially impacts on the computation efficiency. In order to overcome the difficulty, we develop reduced mixed GMsFE basis methods such that the multiscale basis functions are independent of the random parameters and span a low-dimensional space. To this end, a greedy algorithm is used to find a set of optimal samples from a training set scattered in the parameter space. Reduced mixed GMsFE basis functions are constructed based on the optimal samples using two optimal sampling strategies: basis-oriented cross-validation and proper orthogonal decomposition. Although the dimension of the space spanned by the reduced mixed GMsFE basis functions is much smaller than the dimension of the original full order model, the online computation still depends on the number of coarse degree of freedoms. To significantly improve the online computation, we integrate the reduced mixed GMsFE basis methods with sparse tensor approximation and obtain a sparse representation for the model's outputs. The sparse representation is very efficient for evaluating the model's outputs for many instances of parameters. To illustrate the efficacy of the proposed methods, we present a few numerical examples for elliptic PDEs with multiscale and random inputs. In particular, a two-phase flow model in
Theoretical models for fluid thermodynamics based on the quasi-Gaussian entropy theory
Amadei, Andrea
1998-01-01
Summary The theoretical modeling of fluid thermodynamics is one of the most challenging fields in physical chemistry. In fact the fluid behavior, except at very low density conditions, is still extremely difficult to be modeled from a statistical mechanical point of view, as for any realistic model
THEORETICAL FLOW MODEL THROUGH A CENTRIFUGAL PUMP USED FOR WATER SUPPLY IN AGRICULTURE IRRIGATION
Directory of Open Access Journals (Sweden)
SCHEAUA Fanel Dorel
2017-05-01
motion of the rotor. A theoretical model for calculating the flow of the working fluid through the interior of a centrifugal pump model is presented in this paper as well as the numerical analysis on the virtual model performed with the ANSYS CFX software in order to highlight the flow parameters and flow path-lines that are formed during centrifugal pump operation.
Lise, W.; Linderhof, V.G.M.; Kuik, O.; Kemfert, C.; Ostling, R.; Heinzow, T.
2006-01-01
This paper develops a static computational game theoretic model. Illustrative results for the liberalising European electricity market are given to demonstrate the type of economic and environmental results that can be generated with the model. The model is empirically calibrated to eight
1995-01-01
The theoretical bases for the Release 1 algorithms that will be used to process satellite data for investigation of the Clouds and Earth's Radiant Energy System (CERES) are described. The architecture for software implementation of the methodologies is outlined. Volume 3 details the advanced CERES methods for performing scene identification and inverting each CERES scanner radiance to a top-of-the-atmosphere (TOA) flux. CERES determines cloud fraction, height, phase, effective particle size, layering, and thickness from high-resolution, multispectral imager data. CERES derives cloud properties for each pixel of the Tropical Rainfall Measuring Mission (TRMM) visible and infrared scanner and the Earth Observing System (EOS) moderate-resolution imaging spectroradiometer. Cloud properties for each imager pixel are convolved with the CERES footprint point spread function to produce average cloud properties for each CERES scanner radiance. The mean cloud properties are used to determine an angular distribution model (ADM) to convert each CERES radiance to a TOA flux. The TOA fluxes are used in simple parameterization to derive surface radiative fluxes. This state-of-the-art cloud-radiation product will be used to substantially improve our understanding of the complex relationship between clouds and the radiation budget of the Earth-atmosphere system.
Stress fluctuations in fracture networks from theoretical and numerical models
Davy, P.; Darcel, C.; Mas Ivars, D.; Le Goc, R.
2017-12-01
We analyze the spatial fluctuations of stress in a simple tridimensional model constituted by a population of disc-shaped fractures embedded in an elastic matrix with uniform and isotropic properties. The fluctuations arise from the classical stress enhancement at fracture tips and stress shadowing around fracture centers that are amplified or decreased by the interactions between close-by fractures. The distribution of local stresses is calculated at the elementary mesh scale with the 3DEC numerical program based on the distinct element method. As expected, the stress distributions vary with fracture density, the larger is the density, the wider is the distribution. For freely slipping fractures, it is mainly controlled by the percolation parameter p (i.e., the total volume of spheres surrounding fractures). For stresses smaller than the remote deviatoric stress, the distribution depends only on for the range of density that has been studied. For large stresses, the distribution decreases exponentially when increasing stress, with a characteristic stress that increases with entailing a widening of the stress distribution. We extend the analysis to fractures with plane resistance defined by an elastic shear stiffness ks and a slip Coulomb threshold. A consequence of the fracture plane resistance is to lower the stress perturbation in the surrounding matrix by a factor that depends on the ratio between ks and a fracture-matrix stiffness km mainly dependent on the ratio between Young modulus and fracture size. km is also the ratio between the remote shear stress and the displacement across the fracture plane in the case of freely slipping fractures. A complete analytical derivation of the expressions of the stress perturbations and of the fracture displacements is obtained and checked with numerical simulations. In the limit ks >> km, the stress perturbation tends to 0 and the stress state is spatially uniform. The analysis allows us to quantify the intensity of the
Differentiating neutrino models on the basis of $\\theta_{13}$ and lepton flavor violation
Energy Technology Data Exchange (ETDEWEB)
Albright, Carl H.; /Northern Illinois U. /Fermilab
2008-03-01
The authors show how models of neutrino masses and mixings can be differentiated on the basis of their predictions for {theta}{sub 13} and lepton flavor violation in radiative charged lepton decays and {mu} - e conversion. They illustrate the lepton flavor violation results for five predictive SO(10) SUSY GUT models and point out the relative importance of their heavy right-handed neutrino mass spectra and {theta}{sub 13} predictions.
Beam-hardening correction in CT based on basis image and TV model
International Nuclear Information System (INIS)
Li Qingliang; Yan Bin; Li Lei; Sun Hongsheng; Zhang Feng
2012-01-01
In X-ray computed tomography, the beam hardening leads to artifacts and reduces the image quality. It analyzes how beam hardening influences on original projection. According, it puts forward a kind of new beam-hardening correction method based on the basis images and TV model. Firstly, according to physical characteristics of the beam hardening an preliminary correction model with adjustable parameters is set up. Secondly, using different parameters, original projections are operated by the correction model. Thirdly, the projections are reconstructed to obtain a series of basis images. Finally, the linear combination of basis images is the final reconstruction image. Here, with total variation for the final reconstruction image as the cost function, the linear combination coefficients for the basis images are determined according to iterative method. To verify the effectiveness of the proposed method, the experiments are carried out on real phantom and industrial part. The results show that the algorithm significantly inhibits cup and strip artifacts in CT image. (authors)
Directory of Open Access Journals (Sweden)
Михаил Юрьевич Чернышов
2013-12-01
Full Text Available A software complex (SC elaborated by the authors on the basis of the language LMPL and representing a software tool intended for synthesis of applied software models and meta-models constructed on the basis of mathematical programming (MP principles is described. LMPL provides for an explicit form of declarative representation of MP-models, presumes automatic constructing and transformation of models and the capability of adding external software packages. The following software versions of the SC have been implemented: 1 a SC intended for representing the process of choosing an optimal hydroelectric power plant model (on the principles of meta-modeling and 2 a SC intended for representing the logic-sense relations between the models of a set of discourse formations in the discourse meta-model.
Directory of Open Access Journals (Sweden)
O. L. Tyutkin
2008-04-01
Full Text Available In the article the theoretical bases of determination of the stressed-and-strained state of clay massif from positions of the theory of viscous-elastic-plastic medium are presented.
Scholz, Stefan; Graf von der Schulenburg, Johann-Matthias; Greiner, Wolfgang
2015-11-17
Regional differences in physician supply can be found in many health care systems, regardless of their organizational and financial structure. A theoretical model is developed for the physicians' decision on office allocation, covering demand-side factors and a consumption time function. To test the propositions following the theoretical model, generalized linear models were estimated to explain differences in 412 German districts. Various factors found in the literature were included to control for physicians' regional preferences. Evidence in favor of the first three propositions of the theoretical model could be found. Specialists show a stronger association to higher populated districts than GPs. Although indicators for regional preferences are significantly correlated with physician density, their coefficients are not as high as population density. If regional disparities should be addressed by political actions, the focus should be to counteract those parameters representing physicians' preferences in over- and undersupplied regions.
MENGUKUR KESUKSESAN SISTEM AKUNTANSI INSTANSI BASIS AKRUAL (SAIBA MENGGUNAKAN MODEL DeLONE & McLEAN
Directory of Open Access Journals (Sweden)
Noviyanti Noviyanti
2017-01-01
Full Text Available ABSTRACT The aim of this study is to determine the user’s perception of Accrual Basis Institution Accounting System (SAIBA in the ministry/agency in the first year of implementation of accrual-based government’s financial statements. Updated D & M IS Success Model is used to assess the success of SAIBA as a mandatory system in Indonesian Government Accounting. Respondents are operators of Institution Accounting System (SAI in the ministries/agencies, who are joining the Workshop on Preparation and Study of Financial Statements at Pusdiklat Anggaran dan Perbendaharaan Bogor in November 2015 and selected using purposive sampling method. The Primary data were obtained through questionnaires that were collected from 204 respondents, which were then analyzed using structural equation modeling. This study found that SAIBA can be categorized as a successful information for each dimension of success in the Updated D&M IS Success Model. Respondents assessed the system quality, the information quality and service quality of SAIBA tend to be good. However, respondents indicated the use of SAIBA has no significant effect on user satisfaction, in contrast to the others constructs relationships, the system quality, the information quality and service quality of SAIBA with net benefit and its reciprocal proved to be significant impact. Keywords: SAIBA, updated D&M IS Success Model, accrual basis, government accounting, institution accounting system ABSTRAK Penelitian ini bertujuan untuk mengetahui persepsi pengguna terhadap Sistem Akuntansi Instansi Basis Akrual (SAIBA pada Kementerian/Lembaga di tahun pertama penggunaanya pada pembuatan laporan keuangan pemerintah basis akrual. Model Kesuksesan Sistem Informasi yang diperbaharui (Updated D&M IS Success Model digunakan untuk menilai kesuksesan SAIBA yang penggunaannya bersifat wajib pada Akuntansi Pemerintahan Indonesia yang berbasis akrual. Responden adalah operator Sistem Akuntansi Instansi (SAI
Nicassio, Perry M.
1985-01-01
Summarizes clinical and research literature on Southeast Asian refugees' adjustment in the United States and proposes the adoption of theoretical models that may help explain individual differences. Reports that acculturation, learned helplessness, and stress management models appear to aid the conceptualizing of refugee problems and provide a…
International Nuclear Information System (INIS)
Lind, M.
2005-10-01
Multilevel Flow Modeling (MFM) has proven to be an effective modeling tool for reasoning about plant failure and control strategies and is currently exploited for operator support in diagnosis and on-line alarm analysis. Previous MFM research was focussed on representing goals and functions of process plants which generate, transform and distribute mass and energy. However, only a limited consideration has been given to the problems of modeling the control systems. Control functions are indispensable for operating any industrial plant. But modeling of control system functions has proven to be a more challenging problem than modeling functions of energy and mass processes. The problems were discussed by Lind and tentative solutions has been proposed but have not been investigated in depth until recently, partly due to the lack of an appropriate theoretical foundation. The purposes of the present report are to show that such a theoretical foundation for modeling goals and functions of control systems can be built from concepts and theories of action developed by Von Wright and to show how the theoretical foundation can be used to extend MFM with concepts for modeling control systems. The theoretical foundations has been presented in detail elsewhere by the present author without the particular focus on modeling control actions and MFM adopted here. (au)
D. Todd Jones-Farrand; Todd M. Fearer; Wayne E. Thogmartin; Frank R. Thompson; Mark D. Nelson; John M. Tirpak
2011-01-01
Selection of a modeling approach is an important step in the conservation planning process, but little guidance is available. We compared two statistical and three theoretical habitat modeling approaches representing those currently being used for avian conservation planning at landscape and regional scales: hierarchical spatial count (HSC), classification and...
A new theoretical model of the quasistatic single-fiber pullout problem: Analysis of stress field
DEFF Research Database (Denmark)
Qing, Hai
2013-01-01
results of the stress distributions, in both fully bonded region and fully debonded region, are presented for a typical glass/epoxy composite system with different fibre volume fraction and model length. In fully bonded region, the theoretical results from present model are more accurate compared...... solution. © 2013 Elsevier Ltd. All rights reserved....
Energy Technology Data Exchange (ETDEWEB)
Lind, M. [Oersted - DTU, Kgs. Lyngby (Denmark)
2005-10-01
Multilevel Flow Modeling (MFM) has proven to be an effective modeling tool for reasoning about plant failure and control strategies and is currently exploited for operator support in diagnosis and on-line alarm analysis. Previous MFM research was focussed on representing goals and functions of process plants which generate, transform and distribute mass and energy. However, only a limited consideration has been given to the problems of modeling the control systems. Control functions are indispensable for operating any industrial plant. But modeling of control system functions has proven to be a more challenging problem than modeling functions of energy and mass processes. The problems were discussed by Lind and tentative solutions has been proposed but have not been investigated in depth until recently, partly due to the lack of an appropriate theoretical foundation. The purposes of the present report are to show that such a theoretical foundation for modeling goals and functions of control systems can be built from concepts and theories of action developed by Von Wright and to show how the theoretical foundation can be used to extend MFM with concepts for modeling control systems. The theoretical foundations has been presented in detail elsewhere by the present author without the particular focus on modeling control actions and MFM adopted here. (au)
Hsieh, Pei-Hsuan; Sullivan, Jeremy R.; Sass, Daniel A.; Guerra, Norma S.
2012-01-01
Research has identified factors associated with academic success by evaluating relations among psychological and academic variables, although few studies have examined theoretical models to understand the complex links. This study used structural equation modeling to investigate whether the relation between test anxiety and final course grades was…
International Nuclear Information System (INIS)
Lukaszek, W.; Kucypera, S.
1982-01-01
The basis of a semianalytic method for calculating attenuation of rays (neutron, gamma) in material medium is described. The method was applied in determining the neutrons' flux density in one dimensional Cartesian geometry of the reflector and the shield. (author)
137Cs applicability to soil erosion assessment: theoretical and empirical model
International Nuclear Information System (INIS)
Andrello, Avacir Casanova
2004-02-01
The soil erosion processes acceleration and the increase of soil erosion rates due to anthropogenic perturbation in soil-weather-vegetation equilibrium has influenced in the soil quality and environment. So, the possibility to assess the amplitude and severity of soil erosion impact on the productivity and quality of soil is important so local scale as regional and global scale. Several models have been developed to assess the soil erosion so qualitative as quantitatively. 137 Cs, an anthropogenic radionuclide, have been very used to assess the superficial soil erosion process Empirical and theoretical models were developed on the basis of 137 Cs redistribution as indicative of soil movement by erosive process These models incorporate many parameters that can influence in the soil erosion rates quantification by 137 Cs redistribution. Statistical analysis was realized on the models recommended by IAEA to determinate the influence that each parameter generates in results of the soil redistribution. It was verified that the most important parameter is the 137 Cs redistribution, indicating the necessity of a good determination in the 137 Cs inventory values with a minimum deviation associated with these values. After this, it was associated a 10% deviation in the reference value of 137 Cs inventory and the 5% in the 137 Cs inventory of the sample and was determinate the deviation in results of the soil redistribution calculated by models. The results of soil redistribution was compared to verify if there was difference between the models, but there was not difference in the results determinate by models, unless above 70% of 137 Cs loss. Analyzing three native forests and an area of the undisturbed pasture in the Londrina region, can be verified that the 137 Cs spatial variability in local scale was 15%. Comparing the 137 Cs inventory values determinate in the three native forest with the 137 Cs inventory value determinate in the area of undisturbed pasture in the
Takagi-Sugeno fuzzy models in the framework of orthonormal basis functions.
Machado, Jeremias B; Campello, Ricardo J G B; Amaral, Wagner Caradori
2013-06-01
An approach to obtain Takagi-Sugeno (TS) fuzzy models of nonlinear dynamic systems using the framework of orthonormal basis functions (OBFs) is presented in this paper. This approach is based on an architecture in which local linear models with ladder-structured generalized OBFs (GOBFs) constitute the fuzzy rule consequents and the outputs of the corresponding GOBF filters are input variables for the rule antecedents. The resulting GOBF-TS model is characterized by having only real-valued parameters that do not depend on any user specification about particular types of functions to be used in the orthonormal basis. The fuzzy rules of the model are initially obtained by means of a well-known technique based on fuzzy clustering and least squares. Those rules are then simplified, and the model parameters (GOBF poles, GOBF expansion coefficients, and fuzzy membership functions) are subsequently adjusted by using a nonlinear optimization algorithm. The exact gradients of an error functional with respect to the parameters to be optimized are computed analytically. Those gradients provide exact search directions for the optimization process, which relies solely on input-output data measured from the system to be modeled. An example is presented to illustrate the performance of this approach in the modeling of a complex nonlinear dynamic system.
Energy Technology Data Exchange (ETDEWEB)
Reimus, Paul William [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2017-07-31
This report provides documentation of the mathematical basis for a colloid-facilitated radionuclide transport modeling capability that can be incorporated into GDSA-PFLOTRAN. It also provides numerous test cases against which the modeling capability can be benchmarked once the model is implemented numerically in GDSA-PFLOTRAN. The test cases were run using a 1-D numerical model developed by the author, and the inputs and outputs from the 1-D model are provided in an electronic spreadsheet supplement to this report so that all cases can be reproduced in GDSA-PFLOTRAN, and the outputs can be directly compared with the 1-D model. The cases include examples of all potential scenarios in which colloid-facilitated transport could result in the accelerated transport of a radionuclide relative to its transport in the absence of colloids. Although it cannot be claimed that all the model features that are described in the mathematical basis were rigorously exercised in the test cases, the goal was to test the features that matter the most for colloid-facilitated transport; i.e., slow desorption of radionuclides from colloids, slow filtration of colloids, and equilibrium radionuclide partitioning to colloids that is strongly favored over partitioning to immobile surfaces, resulting in a substantial fraction of radionuclide mass being associated with mobile colloids.
Expectancy-Violation and Information-Theoretic Models of Melodic Complexity
Directory of Open Access Journals (Sweden)
Tuomas Eerola
2016-07-01
Full Text Available The present study assesses two types of models for melodic complexity: one based on expectancy violations and the other one related to an information-theoretic account of redundancy in music. Seven different datasets spanning artificial sequences, folk and pop songs were used to refine and assess the models. The refinement eliminated unnecessary components from both types of models. The final analysis pitted three variants of the two model types against each other and could explain from 46-74% of the variance in the ratings across the datasets. The most parsimonious models were identified with an information-theoretic criterion. This suggested that the simplified expectancy-violation models were the most efficient for these sets of data. However, the differences between all optimized models were subtle in terms both of performance and simplicity.
Directory of Open Access Journals (Sweden)
Xiaojin Li
2013-01-01
Full Text Available Previous studies have investigated both structural and functional brain networks via graph-theoretical methods. However, there is an important issue that has not been adequately discussed before: what is the optimal theoretical graph model for describing the structural networks of human brain? In this paper, we perform a comparative study to address this problem. Firstly, large-scale cortical regions of interest (ROIs are localized by recently developed and validated brain reference system named Dense Individualized Common Connectivity-based Cortical Landmarks (DICCCOL to address the limitations in the identification of the brain network ROIs in previous studies. Then, we construct structural brain networks based on diffusion tensor imaging (DTI data. Afterwards, the global and local graph properties of the constructed structural brain networks are measured using the state-of-the-art graph analysis algorithms and tools and are further compared with seven popular theoretical graph models. In addition, we compare the topological properties between two graph models, namely, stickiness-index-based model (STICKY and scale-free gene duplication model (SF-GD, that have higher similarity with the real structural brain networks in terms of global and local graph properties. Our experimental results suggest that among the seven theoretical graph models compared in this study, STICKY and SF-GD models have better performances in characterizing the structural human brain network.
Misganaw Abebe; Jun-Seok Yoon; Beom-Soo Kang
2017-01-01
Springback in multi-point dieless forming (MDF) is a common problem because of the small deformation and blank holder free boundary condition. Numerical simulations are widely used in sheet metal forming to predict the springback. However, the computational time in using the numerical tools is time costly to find the optimal process parameters value. This study proposes radial basis function (RBF) to replace the numerical simulation model by using statistical analyses that are based on a desi...
Consideration of age-dependent radium retention in people on the basis of the beagle model
International Nuclear Information System (INIS)
Parks, N.J.; Keane, A.T.
1982-01-01
Skeletal calcification as a function of age has been estimated for human females on the basis of the beagle model. The interspecies scaling of radium retention characteristics has been described in terms of skeletal calcium addition rates for beagles and humans. radium retention in humans exposed to less than 200 μCi was greatest in individuals who were less than 18 years old when exposed
Comparison of two mean-field based theoretical analysis methods for SIS model
Zhang, Jiaquan; Lu, Dan; Yang, Shunkun
2017-11-01
Epidemic spreading has been intensively studied in SIS epidemic model. Although the mean-field theory of SIS model has been widely used in the research, there is a lack of comparative results between different theoretical calculations, and the differences between them should be systematically explained. In this paper, we have compared different theoretical solutions for mean-field theory and explained the underlying reason. We first describe the differences between different equations for mean-field theory in different networks. The results show that the difference between mean-field reaction equations is due to the different probability consideration for the infection process. This finding will help us to design better theoretical solutions for epidemic models.
Hankin, R K; Britter, R E
1999-05-14
The Major Hazard Assessment Unit of the Health and Safety Executive (HSE) provides advice to local planning authorities on land use planning in the vicinity of major hazard sites. For sites with the potential for large scale releases of toxic heavy gases such as chlorine this advice is based on risk levels and is informed by use of the computerised risk assessment tool RISKAT [C. Nussey, M. Pantony, R. Smallwood, HSE's risk assessment tool RISKAT, Major Hazards: Onshore and Offshore, October, 1992]. At present RISKAT uses consequence models for heavy gas dispersion that assume flat terrain. This paper is the first part of a three part paper. Part 1 describes the mathematical basis of TWODEE, the Health and Safety Laboratory's shallow layer model for heavy gas dispersion. The shallow layer approach used by TWODEE is a compromise between the complexity of CFD models and the simpler integral models. Motivated by the low aspect ratio of typical heavy gas clouds, shallow layer models use depth-averaged variables to describe the flow behaviour. This approach is particularly well suited to assess the effect of complex terrain because the downslope buoyancy force is easily included. Entrainment may be incorporated into a shallow layer model by the use of empirical formulae. Part 2 of this paper presents the numerical scheme used to solve the TWODEE mathematical model, and validated against theoretical results. Part 3 compares the results of the TWODEE model with the experimental results taken at Thorney Island [J. McQuaid, B. Roebuck, The dispersion of heavier-than-air gas from a fenced enclosure. Final report to the US Coast Guard on contract with the Health and Safety Executive, Technical Report RPG 1185, Safety Engineering Laboratory, Research and Laboratory Services Division, Broad Lane, Sheffield S3 7HQ, UK, 1985]. Crown Copyright Copyright 1999 Published by Elsevier Science B.V.
Jennings, Karen M
Using a nursing theoretical framework to understand, elucidate, and propose nursing research is fundamental to knowledge development. This article presents the Roy Adaptation Model as a theoretical framework to better understand individuals with anorexia nervosa during acute treatment, and the role of nursing assessments and interventions in the promotion of weight restoration. Nursing assessments and interventions situated within the Roy Adaptation Model take into consideration how weight restoration does not occur in isolation but rather reflects an adaptive process within external and internal environments, and has the potential for more holistic care.
Experimental study and theoretical modeling of bidimensional beam fanning: application to DPCM
Mailhan, C.; Goetz, M.; Fressengeas, N.; Kugel, G.
2001-10-01
Features like efficiency and stability of the double phase conjugate mirror (DPCM) in BaTiO 3 obviously depend on the beam fanning (BF) experienced by each incident beam. We propose here a new approach to DPCM optimization which consists in studying the BF phenomenon for each interacting beam. This allows one to choose the best angular configuration of the incident beams in DPCM. The investigation is experimental, by recording the fanning patterns, and also theoretical, by interpreting numerically these patterns on the basis of the coupling gain maximization in the two-wave mixing theory. We focus on the influence of the incident beam width and incidence angle.
Opaque models: Using drugs and dreams to explore the neurobiological basis of mental phenomena.
Langlitz, Nicolas
2017-01-01
On the basis of four historical and ethnographic case studies of modeling in neuroscience laboratories, this chapter introduces a distinction between transparent and opaque models. A transparent model is a simplified representation of a real world phenomenon. If it is not patently clear, it is at least much better comprehended than its objects of representation. An opaque model, by contrast, looks at one only partially understood phenomenon to stand in for another partially understood phenomenon. Here, the model is often just as complex as its target. Examples of such opaque models discussed in this chapter are the use of hallucinogen intoxication in humans and animals as well as the dreaming brain as models of psychosis as well as the dreaming brain as a model of consciousness in general. Several functions of opaque models are discussed, ranging from the generation of funding to the formulation of new research questions. While science studies scholars have often emphasized the epistemic fertility of failures of representation, the opacity of hallucinogen intoxications and dreams seems to have diminished the potential to produce positive knowledge from the representational relationship between the supposed models and their targets. Bidirectional comparisons between inebriation, dreaming, and psychosis, however, proved to be generative on the level of basic science. Moreover, the opaque models discussed in this chapter implicated cosmologies that steered research endeavors into certain directions rather than others. © 2017 Elsevier B.V. All rights reserved.
International Nuclear Information System (INIS)
Woods, D.D.; Roth, E.M.
1986-01-01
This paper reviews the major theoretical literatures that are relevant to modeling human cognitive activities important to nuclear power plant safety. The traditions considered include control theory, communication theory, statistical decision theory, information processing models and symbolic processing models. The review reveals a gradual convergence towards models that incorporate elements from multiple traditions. Models from the control theory tradition have gradually evolved to include rich knowledge representations borrowed from the symbolic processing work. At the same time theorists in the symbolic processing tradition are beginning to grapple with some of the critical issues involved in modeling complex real world domain
Theoretical-empirical model of the steam-water cycle of the power unit
Directory of Open Access Journals (Sweden)
Grzegorz Szapajko
2010-06-01
Full Text Available The diagnostics of the energy conversion systems’ operation is realised as a result of collecting, processing, evaluatingand analysing the measurement signals. The result of the analysis is the determination of the process state. It requires a usageof the thermal processes models. Construction of the analytical model with the auxiliary empirical functions built-in brings satisfyingresults. The paper presents theoretical-empirical model of the steam-water cycle. Worked out mathematical simulation model containspartial models of the turbine, the regenerative heat exchangers and the condenser. Statistical verification of the model is presented.
Dependence of tropical cyclone development on coriolis parameter: A theoretical model
Deng, Liyuan; Li, Tim; Bi, Mingyu; Liu, Jia; Peng, Melinda
2018-03-01
A simple theoretical model was formulated to investigate how tropical cyclone (TC) intensification depends on the Coriolis parameter. The theoretical framework includes a two-layer free atmosphere and an Ekman boundary layer at the bottom. The linkage between the free atmosphere and the boundary layer is through the Ekman pumping vertical velocity in proportion to the vorticity at the top of the boundary layer. The closure of this linear system assumes a simple relationship between the free atmosphere diabatic heating and the boundary layer moisture convergence. Under a set of realistic atmospheric parameter values, the model suggests that the most preferred latitude for TC development is around 5° without considering other factors. The theoretical result is confirmed by high-resolution WRF model simulations in a zero-mean flow and a constant SST environment on an f -plane with different Coriolis parameters. Given an initially balanced weak vortex, the TC-like vortex intensifies most rapidly at the reference latitude of 5°. Thus, the WRF model simulations confirm the f-dependent characteristics of TC intensification rate as suggested by the theoretical model.
A basis for designing digital library maturity model: Meta-synthesis method application
Directory of Open Access Journals (Sweden)
Fatemeh Sheikhshoaei
2017-06-01
Full Text Available Digital Library (DL development is faced with many challenges which cannot be overcome all at once. In such cases which are so complex, maturity models are utilized. In a maturity model, features of a phenomenon are classified into few levels so that improving or realizing the features of each level is the prerequisite of going to the next level. DL can also be approached by maturity model more efficiently and effectively. Since the maturity model for DL has not been designed yet, first, a literature review of the DL and maturity models using a qualitative approach and meta-synthesis method was done. According to the findings of the literature review, the maturity characteristics of DL are proposed to be a basis for designing DL maturity model. Since the concept of maturity and DL is extensive and has several dimensions, meta-synthesis has been found as a suitable method for comprehensive integration of the models offered in other areas with the existing literature in the field of DL based on their interpretation. To do so, 68 papers (38 in the field of DL and 30 in the field of maturity models in various fields were selected from the available resources. By analyzing these papers, three categories, seven concepts, and 35 codes obtained as DL maturity features. Among these findings, the focuses of previous studies have been on the use of software/ hardware systems as supporter and enabler of DL and the DL content. The found features, in addition to be a basis for designing of digital library model, can be a tool in the hands of project managers of DL for assessing the status of their projects and planning to achieve higher levels of maturity.
Theoretical model simulations for the global Thermospheric Mapping Study (TMS) periods
Rees, D.; Fuller-Rowell, T. J.
Theoretical and semiempirical models of the solar UV/EUV and of the geomagnetic driving forces affecting the terrestrial mesosphere and thermosphere have been used to generate a series of representative numerical time-dependent and global models of the thermosphere, for the range of solar and geoamgnetic activity levels which occurred during the three Thermospheric Mapping Study periods. The simulations obtained from these numerical models are compared with observations, and with the results of semiempirical models of the thermosphere. The theoretical models provide a record of the magnitude of the major driving forces which affected the thermosphere during the study periods, and a baseline against which the actual observed structure and dynamics can be compared.
Ryu, Duchwan
2013-03-01
The sea surface temperature (SST) is an important factor of the earth climate system. A deep understanding of SST is essential for climate monitoring and prediction. In general, SST follows a nonlinear pattern in both time and location and can be modeled by a dynamic system which changes with time and location. In this article, we propose a radial basis function network-based dynamic model which is able to catch the nonlinearity of the data and propose to use the dynamically weighted particle filter to estimate the parameters of the dynamic model. We analyze the SST observed in the Caribbean Islands area after a hurricane using the proposed dynamic model. Comparing to the traditional grid-based approach that requires a supercomputer due to its high computational demand, our approach requires much less CPU time and makes real-time forecasting of SST doable on a personal computer. Supplementary materials for this article are available online. © 2013 American Statistical Association.
Apparel shopping behaviour – Part 1: Towards the development of a conceptual theoretical model
Directory of Open Access Journals (Sweden)
R Du Preez
2003-10-01
Full Text Available Apparel shopping behaviour in a multicultural society is a complex phenomenon. The objective of this paper is to analyse various theoretical models from two disciplines, namely Consumer Behaviour and Clothing, and to develop a new conceptual theoretical model focussing on variables influencing apparel shopping behaviour in a multicultural consumer society. Variables were presented as market dominated, consumer dominated, and/or market and consumer interaction variables. Retailers, marketers, educators, researchers and students could benefit from the proposed model and recommendations are made in this regard. Part 2 reports on an empirical study based on the proposed conceptual theoretical model and discusses market segments and profiles. Opsomming Klere-aankoopgedrag in ’n multi-kulturele verbruikersamelewing is ’n komplekse fenomeen. Die doelwit van die artikel is om verskeie teoretiese modelle vanuit twee dissiplines, naamlik Verbruikersielkunde en Kleding, te analiseer. ’n Nuwe konseptuele teoretiese model is ontwikkel. Die model fokus op veranderlikes wat klereaankoopgedrag in ’n multi-kulturele verbruikersamelewing beïnvloed. Veranderlikes word gegroepeer op grond van die mate waartoe dit oorheers word deur die mark, verbruiker en/of die interaksie tussen die mark en die verbruiker. Kleinhandelaars, bemarkers, opvoeders, navorsers en studente sou kon voordeel trek uit die voorgestelde model. Aanbevelings word in dié verband gemaak. In Deel 2 word ’n empiriese studie gerapporteer. Dié studie is op hierdie voorgestelde konseptuele teoretiese model gegrond en marksegmente sowel as profiele word bespreek.
Monroe, Scott M.; Mineka, Susan
2008-01-01
Our commentary was intended to stimulate discussion about what we perceive to be shortcomings of the mnemonic model and its research base, in the hope of shedding some light on key questions for understanding posttraumatic stress disorder (PTSD). In our view, Berntsen, Rubin, and Bohni have responded only to what they perceive to be shortcomings…
Theoretical modeling of a new structure of III-V tandem solar cells by ...
African Journals Online (AJOL)
junction solar cell is theoretically investigated by optimizing the thickness of GaAs and GaInPandusing a new optical model to separate the junction between the two solar cell in order to solve problems of tunnel junction and difficulties of fabrication.
Theoretical values of various parameters in the Gummel-Poon model of a bipolar junction transistor
Benumof, R.; Zoutendyk, J.
1986-01-01
Various parameters in the Gummel-Poon model of a bipolar junction transistor are expressed in terms of the basic structure of a transistor. A consistent theoretical approach is used which facilitates an understanding of the foundations and limitations of the derived formulas. The results enable one to predict how changes in the geometry and composition of a transistor would affect performance.
Piper, Llewellyn E
2006-01-01
This article proposes a theoretical model for leaders to use to address organizational human conflict and disruptive behavior in health care organizations. Leadership is needed to improve interpersonal relationships within the workforce. A workforce with a culture of internal conflict will be unable to achieve its full potential to delivery quality patient care.
Λc eν) decay in a field theoretic quark model
Indian Academy of Sciences (India)
The semileptonic decay width of heavy baryons such as ( → ) has been estimated in the framework of a nonrelativistic ﬁeld theoretic quark model where four component quark ﬁeld operators along with a harmonic oscillator wave function are used to describe translationally invariant hadronic states. The present ...
Theoretical model of the density of states of random binary alloys
International Nuclear Information System (INIS)
Zekri, N.; Brezini, A.
1991-09-01
A theoretical formulation of the density of states for random binary alloys is examined based on a mean field treatment. The present model includes both diagonal and off-diagonal disorder and also short-range order. Extensive results are reported for various concentrations and compared to other calculations. (author). 22 refs, 6 figs
A Game-Theoretic Model of Grounding for Referential Communication Tasks
Thompson, William
2009-01-01
Conversational grounding theory proposes that language use is a form of rational joint action, by which dialog participants systematically and collaboratively add to their common ground of shared knowledge and beliefs. Following recent work applying "game theory" to pragmatics, this thesis develops a game-theoretic model of grounding that…
Theoretical investigations of the new Cokriging method for variable-fidelity surrogate modeling
DEFF Research Database (Denmark)
Zimmermann, Ralf; Bertram, Anna
2017-01-01
Cokriging is a variable-fidelity surrogate modeling technique which emulates a target process based on the spatial correlation of sampled data of different levels of fidelity. In this work, we address two theoretical questions associated with the so-called new Cokriging method for variable fidelity...
El-Khouly, Fatma E; van Vuurden, Dannis G; Stroink, Thom; Hulleman, Esther; Kaspers, Gertjan J L; Hendrikse, N Harry; Veldhuijzen van Zanten, Sophie E M
2017-01-01
Despite decades of clinical trials for diffuse intrinsic pontine glioma (DIPG), patient survival does not exceed 10% at two years post-diagnosis. Lack of benefit from systemic chemotherapy may be attributed to an intact bloodbrain barrier (BBB). We aim to develop a theoretical model including
Directory of Open Access Journals (Sweden)
Michael Fröhlich
2013-10-01
Full Text Available In Olympic-distance triathlon, time minimization is the goal in all three disciplines and the two transitions. Running is the key to winning, whereas swimming and cycling performance are less significantly associated with overall competition time. A comparative static simulation calculation based on the individual times of each discipline was done. Furthermore, the share of the discipline in the total time proved that increasing the scope of running training results in an additional performance development. Looking at the current development in triathlon and taking the Olympic Games in London 2012 as an initial basis for model-theoretic simulations of performance development, the first fact that attracts attention is that running becomes more and more the crucial variable in terms of winning a triathlon. Run times below 29:00 minutes in Olympic-distance triathlon will be decisive for winning. Currently, cycle training time is definitely overrepresented. The share of swimming is considered optimal.
Directory of Open Access Journals (Sweden)
Shikul’skaya Ol’ga Mikhaylovna
2018-01-01
Full Text Available Subject: due to the existence of shabby and hazardous dwelling, the housing problem is one of the most relevant problems in the social sphere of the Astrakhan region. The Astrakhan regional construction cluster includes the significant number of the construction organizations, the servicing organizations, which are engaged in the training of personnel for construction, the banks and other credit institutions, which provide the population with mortgage loans, and also regional, municipal authorities and public organizations. The regional construction cluster is the developing social and economic system of heterarchical type. The heterarchy combines both elements of hierarchy and elements of the market relations. Therefore, the task of creation of a common information space of a regional construction cluster on the basis of mathematical, functional and information-logical models is relevant. Research objectives: use functional and mathematical modeling of heterarchical system of a regional construction cluster for development of its information portal. Materials and methods: for creation of structurally-functional model of a regional construction cluster, the methodology of structural analysis in notations of IDEF0, IDEF3, Swimlane was used. As a tool for structurally-functional simulation, we used CASE-tool - AllFusion Process Modeler r7. The mathematical description of logic of regional construction cluster management is based on the theory of sets. Results: the complex of functional models with the set-theoretic description of the system was developed. The business-process model in a notation of IDEF0 well reflects the process hierarchy that best describes the hierarchical communications prevailing in stable functioning of the regulated processes. For its creation the SADT technology was used. When the external disturbances affect the socio-economic system (SES, inertial hierarchical management ceases being effective and the advantage is given
Group theoretical construction of two-dimensional models with infinite sets of conservation laws
International Nuclear Information System (INIS)
D'Auria, R.; Regge, T.; Sciuto, S.
1980-01-01
We explicitly construct some classes of field theoretical 2-dimensional models associated with symmetric spaces G/H according to a general scheme proposed in an earlier paper. We treat the SO(n + 1)/SO(n) and SU(n + 1)/U(n) case, giving their relationship with the O(n) sigma-models and the CP(n) models. Moreover, we present a new class of models associated to the SU(n)/SO(n) case. All these models are shown to possess an infinite set of local conservation laws. (orig.)
Theoretical modeling of zircon's crystal morphology according to data of atomistic calculations
Gromalova, Natalia; Nikishaeva, Nadezhda; Eremin, Nikolay
2017-04-01
Zircon is an essential mineral that is used in the U-Pb dating. Moreover, zircon is highly resistant to radioactive exposure. It is of great interest in solving both fundamental and applied problems associated with the isolation of high-level radioactive waste. There is significant progress in forecasting of the most energetically favorable crystal structures at the present time. Unfortunately, the theoretical forecast of crystal morphology at high technological level is under-explored nowadays, though the estimation of crystal equilibrium habit is extremely important in studying the physical and chemical properties of new materials. For the first time, the thesis about relation of the equilibrium shape of a crystal with its crystal structure was put forward in the works by O.Brave. According to it, the idealized habit is determined in the simplest case by a correspondence with the reticular densities Rhkl of individual faces. This approach, along with all subsequent corrections, does not take into account the nature of atoms and the specific features of the chemical bond in crystals. The atomistic calculations of crystal surfaces are commonly performed using the energetic characteristics of faces, namely, the surface energy (Esurf), which is a measure of the thermodynamic stability of the crystal face. The stable crystal faces are characterized by small positive values of Esurf. As we know from our previous research (Gromalova et al.,2015) one of the constitutive factors affecting the value of the surface energy in calculations is a choice of potentials model. In this regard, we studied several sets of parameters of atomistic interatomic potentials optimized previously. As the first test model («Zircon 1») were used sets of interatomic potentials of interaction Zr-O, Si-O and O-O in the form of Buckingham potentials. To improve playback properties of zircon additionally used Morse potential for a couple of Zr-Si, as well as the three-particle angular harmonic
Identifying the molecular basis of host-parasite coevolution: merging models and mechanisms.
Dybdahl, Mark F; Jenkins, Christina E; Nuismer, Scott L
2014-07-01
Mathematical models of the coevolutionary process have uncovered consequences of host-parasite interactions that go well beyond the traditional realm of the Red Queen, potentially explaining several important evolutionary transitions. However, these models also demonstrate that the specific consequences of coevolution are sensitive to the structure of the infection matrix, which is embedded in models to describe the likelihood of infection in encounters between specific host and parasite genotypes. Traditional cross-infection approaches to estimating infection matrices might be unreliable because evolutionary dynamics and experimental sampling lead to missing genotypes. Consequently, our goal is to identify the likely structure of infection matrices by synthesizing molecular mechanisms of host immune defense and parasite counterdefense with coevolutionary models. This synthesis reveals that the molecular mechanisms of immune reactions, although complex and diverse, conform to two basic models commonly used within coevolutionary theory: matching infection and targeted recognition. Our synthesis also overturns conventional wisdom, revealing that the general models are not taxonomically restricted but are applicable to plants, invertebrates, and vertebrates. Finally, our synthesis identifies several important areas for future research that should improve the explanatory power of coevolutionary models. The most important among these include empirical studies to identify the molecular hotspots of genotypic specificity and theoretical studies examining the consequences of matrices that more accurately represent multistep infection processes and quantitative defenses.
Agha Mohammad Ali Kermani, Mehrdad; Fatemi Ardestani, Seyed Farshad; Aliahmadi, Alireza; Barzinpour, Farnaz
2017-01-01
Influence maximization deals with identification of the most influential nodes in a social network given an influence model. In this paper, a game theoretic framework is developed that models a competitive influence maximization problem. A novel competitive influence model is additionally proposed that incorporates user heterogeneity, message content, and network structure. The proposed game-theoretic model is solved using Nash Equilibrium in a real-world dataset. It is shown that none of the well-known strategies are stable and at least one player has the incentive to deviate from the proposed strategy. Moreover, violation of Nash equilibrium strategy by each player leads to their reduced payoff. Contrary to previous works, our results demonstrate that graph topology, as well as the nodes' sociability and initial tendency measures have an effect on the determination of the influential node in the network.
Theoretical and Empirical Review of Asset Pricing Models: A Structural Synthesis
Directory of Open Access Journals (Sweden)
Saban Celik
2012-01-01
Full Text Available The purpose of this paper is to give a comprehensive theoretical review devoted to asset pricing models by emphasizing static and dynamic versions in the line with their empirical investigations. A considerable amount of financial economics literature devoted to the concept of asset pricing and their implications. The main task of asset pricing model can be seen as the way to evaluate the present value of the pay offs or cash flows discounted for risk and time lags. The difficulty coming from discounting process is that the relevant factors that affect the pay offs vary through the time whereas the theoretical framework is still useful to incorporate the changing factors into an asset pricing models. This paper fills the gap in literature by giving a comprehensive review of the models and evaluating the historical stream of empirical investigations in the form of structural empirical review.
Recent progress in the theoretical modelling of Cepheids and RR Lyrae stars
Marconi, Marcella
2017-09-01
Cepheids and RR Lyrae are among the most important primary distance indicators to calibrate the extragalactic distance ladder and excellent stellar population tracers, for Population I and Population II, respectively. In this paper I first mention some recent theoretical studies of Cepheids and RR Lyrae obtained with different theoretical tools. Then I focus the attention on new results based on nonlinear convective pulsation models in the context of some international projects, including VMC@VISTA and the Gaia collaboration. The open problems for both Cepheids and RR Lyrae are briefly discussed together with some challenging future application.
Ye, Ziran; Wang, Ke; Lu, Chenxi; Jin, Ying; Sui, Chenghua; Yan, Bo; Gao, Fan; Cai, Pinggen; Lv, Bin; Li, Yun; Chen, Naibo; Sun, Guofang; Xu, Fengyun; Ye, Gaoxiang
2018-03-01
We develop a theoretical model that interprets the growth mechanism of zinc (Zn) crystal nanorods on a liquid substrate by thermal evaporation. During deposition, Zn atoms diffuse randomly on an isotropic and quasi-free sustained substrate, the nucleation of the atoms results in the primary nanorod (or seed crystal) growth. Subsequently, a characteristic one-dimensional atomic aggregation is proposed, which leads to the accelerating growth of the crystal nanorod along its preferential growth direction until the growth terminates. The theoretical results are in good agreement with the experimental findings.
Rational Design of Lanthanoid Single-Ion Magnets: Predictive Power of the Theoretical Models.
Baldoví, José J; Duan, Yan; Morales, Roser; Gaita-Ariño, Alejandro; Ruiz, Eliseo; Coronado, Eugenio
2016-09-12
We report two new single-ion magnets (SIMs) of a family of oxydiacetate lanthanide complexes with D3 symmetry to test the predictive capabilities of complete active space ab initio methods (CASSCF and CASPT2) and the semiempirical radial effective charge (REC) model. Comparison of the theoretical predictions of the energy levels, wave functions and magnetic properties with detailed spectroscopic and magnetic characterisation is used to critically discuss the limitations of these theoretical approaches. The need for spectroscopic information for a reliable description of the properties of lanthanide SIMs is emphasised. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Irving, J.; Koepke, C.; Elsheikh, A. H.
2017-12-01
Bayesian solutions to geophysical and hydrological inverse problems are dependent upon a forward process model linking subsurface parameters to measured data, which is typically assumed to be known perfectly in the inversion procedure. However, in order to make the stochastic solution of the inverse problem computationally tractable using, for example, Markov-chain-Monte-Carlo (MCMC) methods, fast approximations of the forward model are commonly employed. This introduces model error into the problem, which has the potential to significantly bias posterior statistics and hamper data integration efforts if not properly accounted for. Here, we present a new methodology for addressing the issue of model error in Bayesian solutions to hydrogeophysical inverse problems that is geared towards the common case where these errors cannot be effectively characterized globally through some parametric statistical distribution or locally based on interpolation between a small number of computed realizations. Rather than focusing on the construction of a global or local error model, we instead work towards identification of the model-error component of the residual through a projection-based approach. In this regard, pairs of approximate and detailed model runs are stored in a dictionary that grows at a specified rate during the MCMC inversion procedure. At each iteration, a local model-error basis is constructed for the current test set of model parameters using the K-nearest neighbour entries in the dictionary, which is then used to separate the model error from the other error sources before computing the likelihood of the proposed set of model parameters. We demonstrate the performance of our technique on the inversion of synthetic crosshole ground-penetrating radar traveltime data for three different subsurface parameterizations of varying complexity. The synthetic data are generated using the eikonal equation, whereas a straight-ray forward model is assumed in the inversion
International Nuclear Information System (INIS)
Fu, Liang-Yu; Wang, Guang-Zhong; Ma, Bin-Guang; Zhang, Hong-Yu
2011-01-01
Highlights: → There exists a universal G:C → A:T mutation bias in three domains of life. → This universal mutation bias has not been sufficiently explained. → A DNA mutation model proposed by Loewdin 40 years ago offers a common explanation. -- Abstract: Recently, numerous genome analyses revealed the existence of a universal G:C → A:T mutation bias in bacteria, fungi, plants and animals. To explore the molecular basis for this mutation bias, we examined the three well-known DNA mutation models, i.e., oxidative damage model, UV-radiation damage model and CpG hypermutation model. It was revealed that these models cannot provide a sufficient explanation to the universal mutation bias. Therefore, we resorted to a DNA mutation model proposed by Loewdin 40 years ago, which was based on inter-base double proton transfers (DPT). Since DPT is a fundamental and spontaneous chemical process and occurs much more frequently within GC pairs than AT pairs, Loewdin model offers a common explanation for the observed universal mutation bias and thus has broad biological implications.
RECENT DEVELOPMENTS OF THE FINANCIAL REPORTING MODEL: THEORETICAL STUDIES IN REVIEW
Bonaci Carmen Giorgiana; Matis Dumitru
2011-01-01
Our paper analyzes the manner in which the financial reporting model evolved towards fair value accounting. After a brief introduction into the context of financial reporting at international level, the analysis focuses on the accounting model of fair value. This is done by synthesizing main studies in accounting research literature that analyze fair value accounting through a theoretical approach. The analysis being developed relies on literature review methodology. The main purpose of the d...
A Theoretical Approach to Financial Therapy: The Development of the Ford Financial Empowerment Model
Directory of Open Access Journals (Sweden)
Kristy L. Archuleta
2012-01-01
Full Text Available The purpose of this paper is to introduce an integrative approach to working with clients experiencing problems related to financial disempowerment. The multi-phase model integrates three theoretically-driven psychotherapy approaches, including cognitive behavioral, narrative, and Virginia Satir’s experiential therapies, and financial counseling techniques to increase one’s sense of financial empowerment. A case study is included to demonstrate the applicability and effectiveness of the model.
SOME ASPECTS OF METHODOLOGICAL BASIS OF BANK’S FINANCIAL SECURITY MODELING
Directory of Open Access Journals (Sweden)
Z. Vasylchenko
2013-05-01
Full Text Available Developed methodical approaches for assessing financial safety of bank. Proposed by authors theoretical concept of integral bank’s financial security index has in its basis indicators of capital sufficiency, capital growth, liquidity and return on assets. Bringing together all the mentioned values is appropriate to do using the reliability function. As an input data for setting this function serve expert evaluations regarding the stability of the object that is under consideration. It was found out, that typically system of expert evaluations has couple of features (advantages, which don’t exclude and also don’t complement each other. These features authors consider by separating them as compensational, non-compensational and partly compensational advantages. It was proved, that in banking it is extremely important itself the realistic setup of the ratio between partial and integral indicators, which are partly inherent to-compensational advantage. Proved that the developed approaches for assessing strategic decisions on financial safety of bank are based on three-level index system: bank’s primary accounting figures; aggregate of special generalized figures which consolidate information on management decisions made in bank to the most possible extent; integral indices of financial safety of bank.
Brown, Roderick W.; Beucher, Romain; Roper, Steven; Persano, Cristina; Stuart, Fin; Fitzgerald, Paul
2013-12-01
Over the last decade major progress has been made in developing both the theoretical and practical aspects of apatite (U-Th)/He thermochronometry and it is now standard practice, and generally seen as best practice, to analyse single grain aliquots. These individual prismatic crystals are often broken and are fragments of larger crystals that have broken during mineral separation along the weak basal cleavage in apatite. This is clearly indicated by the common occurrence of only 1 or no clear crystal terminations present on separated apatite grains, and evidence of freshly broken ends when grains are viewed using a scanning electron microscope. This matters because if the 4He distribution within the whole grain is not homogeneous, because of partial loss due to thermal diffusion for example, then the fragments will all yield ages different from each other and from the whole grain age. Here we use a numerical model with a finite cylinder geometry to approximate 4He ingrowth and thermal diffusion within hexagonal prismatic apatite crystals. This is used to quantify the amount and patterns of inherent, natural age dispersion that arises from analysing broken crystals. A series of systematic numerical experiments were conducted to explore and quantify the pattern and behaviour of this source of dispersion using a set of 5 simple thermal histories that represent a range of plausible geological scenarios. In addition some more complex numerical experiments were run to investigate the pattern and behaviour of grain dispersion seen in several real data sets. The results indicate that natural dispersion of a set of single fragment ages (defined as the range divided by the mean) arising from fragmentation alone varies from c. 7% even for rapid (c. 10 °C/Ma), monotonic cooling to over 50% for protracted, complex histories that cause significant diffusional loss of 4He. The magnitude of dispersion arising from fragmentation scales with the grain cylindrical radius, and is of
International Nuclear Information System (INIS)
2015-11-01
The demands on nuclear fuel have recently been increasing, and include transient regimes, higher discharge burnup and longer fuel cycles. This has resulted in an increase of loads on fuel and core internals. In order to satisfy these demands while ensuring compliance with safety criteria, new national and international programmes have been launched and advanced modelling codes are being developed. The Fukushima Daiichi accident has particularly demonstrated the need for adequate analysis of all aspects of fuel performance to prevent a failure and also to predict fuel behaviour were an accident to occur.This publication presents the Proceedings of the Technical Meeting on Modelling of Water Cooled Fuel Including Design Basis and Severe Accidents, which was hosted by the Nuclear Power Institute of China (NPIC) in Chengdu, China, following the recommendation made in 2013 at the IAEA Technical Working Group on Fuel Performance and Technology. This recommendation was in agreement with IAEA mid-term initiatives, linked to the post-Fukushima IAEA Nuclear Safety Action Plan, as well as the forthcoming Coordinated Research Project (CRP) on Fuel Modelling in Accident Conditions. At the technical meeting in Chengdu, major areas and physical phenomena, as well as types of code and experiment to be studied and used in the CRP, were discussed. The technical meeting provided a forum for international experts to review the state of the art of code development for modelling fuel performance of nuclear fuel for water cooled reactors with regard to steady state and transient conditions, and for design basis and early phases of severe accidents, including experimental support for code validation. A round table discussion focused on the needs and perspectives on fuel modelling in accident conditions. This meeting was the ninth in a series of IAEA meetings, which reflects Member States’ continuing interest in nuclear fuel issues. The previous meetings were held in 1980 (jointly with
Walsh, Matthew M; Gluck, Kevin A; Gunzelmann, Glenn; Jastrzembski, Tiffany; Krusmark, Michael
2018-03-02
The spacing effect is among the most widely replicated empirical phenomena in the learning sciences, and its relevance to education and training is readily apparent. Yet successful applications of spacing effect research to education and training is rare. Computational modeling can provide the crucial link between a century of accumulated experimental data on the spacing effect and the emerging interest in using that research to enable adaptive instruction. In this paper, we review relevant literature and identify 10 criteria for rigorously evaluating computational models of the spacing effect. Five relate to evaluating the theoretic adequacy of a model, and five relate to evaluating its application potential. We use these criteria to evaluate a novel computational model of the spacing effect called the Predictive Performance Equation (PPE). Predictive Performance Equation combines elements of earlier models of learning and memory including the General Performance Equation, Adaptive Control of Thought-Rational, and the New Theory of Disuse, giving rise to a novel computational account of the spacing effect that performs favorably across the complete sets of theoretic and applied criteria. We implemented two other previously published computational models of the spacing effect and compare them to PPE using the theoretic and applied criteria as guides. © 2018 Cognitive Science Society, Inc.
Decision support models for solid waste management: Review and game-theoretic approaches
Energy Technology Data Exchange (ETDEWEB)
Karmperis, Athanasios C., E-mail: athkarmp@mail.ntua.gr [Sector of Industrial Management and Operational Research, School of Mechanical Engineering, National Technical University of Athens, Iroon Polytechniou 9, 15780 Athens (Greece); Army Corps of Engineers, Hellenic Army General Staff, Ministry of Defence (Greece); Aravossis, Konstantinos; Tatsiopoulos, Ilias P.; Sotirchos, Anastasios [Sector of Industrial Management and Operational Research, School of Mechanical Engineering, National Technical University of Athens, Iroon Polytechniou 9, 15780 Athens (Greece)
2013-05-15
Highlights: ► The mainly used decision support frameworks for solid waste management are reviewed. ► The LCA, CBA and MCDM models are presented and their strengths, weaknesses, similarities and possible combinations are analyzed. ► The game-theoretic approach in a solid waste management context is presented. ► The waste management bargaining game is introduced as a specific decision support framework. ► Cooperative and non-cooperative game-theoretic approaches to decision support for solid waste management are discussed. - Abstract: This paper surveys decision support models that are commonly used in the solid waste management area. Most models are mainly developed within three decision support frameworks, which are the life-cycle assessment, the cost–benefit analysis and the multi-criteria decision-making. These frameworks are reviewed and their strengths and weaknesses as well as their critical issues are analyzed, while their possible combinations and extensions are also discussed. Furthermore, the paper presents how cooperative and non-cooperative game-theoretic approaches can be used for the purpose of modeling and analyzing decision-making in situations with multiple stakeholders. Specifically, since a waste management model is sustainable when considering not only environmental and economic but also social aspects, the waste management bargaining game is introduced as a specific decision support framework in which future models can be developed.
A Dynamical Model of Pitch Memory Provides an Improved Basis for Implied Harmony Estimation
Kim, Ji Chul
2017-01-01
Tonal melody can imply vertical harmony through a sequence of tones. Current methods for automatic chord estimation commonly use chroma-based features extracted from audio signals. However, the implied harmony of unaccompanied melodies can be difficult to estimate on the basis of chroma content in the presence of frequent nonchord tones. Here we present a novel approach to automatic chord estimation based on the human perception of pitch sequences. We use cohesion and inhibition between pitches in auditory short-term memory to differentiate chord tones and nonchord tones in tonal melodies. We model short-term pitch memory as a gradient frequency neural network, which is a biologically realistic model of auditory neural processing. The model is a dynamical system consisting of a network of tonotopically tuned nonlinear oscillators driven by audio signals. The oscillators interact with each other through nonlinear resonance and lateral inhibition, and the pattern of oscillatory traces emerging from the interactions is taken as a measure of pitch salience. We test the model with a collection of unaccompanied tonal melodies to evaluate it as a feature extractor for chord estimation. We show that chord tones are selectively enhanced in the response of the model, thereby increasing the accuracy of implied harmony estimation. We also find that, like other existing features for chord estimation, the performance of the model can be improved by using segmented input signals. We discuss possible ways to expand the present model into a full chord estimation system within the dynamical systems framework. PMID:28522983
Establishment and validation for the theoretical model of the vehicle airbag
Zhang, Junyuan; Jin, Yang; Xie, Lizhe; Chen, Chao
2015-05-01
The current design and optimization of the occupant restraint system (ORS) are based on numerous actual tests and mathematic simulations. These two methods are overly time-consuming and complex for the concept design phase of the ORS, though they're quite effective and accurate. Therefore, a fast and directive method of the design and optimization is needed in the concept design phase of the ORS. Since the airbag system is a crucial part of the ORS, in this paper, a theoretical model for the vehicle airbag is established in order to clarify the interaction between occupants and airbags, and further a fast design and optimization method of airbags in the concept design phase is made based on the proposed theoretical model. First, the theoretical expression of the simplified mechanical relationship between the airbag's design parameters and the occupant response is developed based on classical mechanics, then the momentum theorem and the ideal gas state equation are adopted to illustrate the relationship between airbag's design parameters and occupant response. By using MATLAB software, the iterative algorithm method and discrete variables are applied to the solution of the proposed theoretical model with a random input in a certain scope. And validations by MADYMO software prove the validity and accuracy of this theoretical model in two principal design parameters, the inflated gas mass and vent diameter, within a regular range. This research contributes to a deeper comprehension of the relation between occupants and airbags, further a fast design and optimization method for airbags' principal parameters in the concept design phase, and provides the range of the airbag's initial design parameters for the subsequent CAE simulations and actual tests.
Improving the theoretical foundations of the multi-mode transport model
International Nuclear Information System (INIS)
Bateman, G.; Kritz, A.H.; Redd, A.J.; Erba, M.; Rewoldt, G.; Weiland, J.; Strand, P.; Kinsey, J.E.; Scott, B.
2001-01-01
A new version of the Multi-Mode transport model, designated MMM98, is being developed with improved theoretical foundations, in an ongoing effort to predict the temperature and density profiles in tokamaks. For transport near the edge of the plasma, MMM98 uses a new model based on 3-D nonlinear simulations of drift Alfven mode turbulence. Flow shear stabilization effects have been added to the Weiland model for Ion Temperature Gradient and Trapped Electron Modes, which usually dominates in most of the plasma core. For transport near the magnetic axis at high beta, a new kinetic ballooning mode model has been constructed based on FULL stability code computations. (author)
International Nuclear Information System (INIS)
Grundmann, U.; Rohde, U.; Naumann, B.
1985-01-01
Studies on theoretical simulation of the dynamic behaviour of the AST-500 type reactor primary coolant system are summarized. The first version of a dynamic model in the form of the DYNAST code is described. The DYNAST code is based on a one-dimensional description of the primary coolant circuit including core, draught stack, and intermediate heat exchanger, a vapour dome model, and the point model of neutron kinetics. With the aid of the steady-state computational part of the DYNAST code, studies have been performed on different steady-state operating conditions. Furthermore, some methodological investigations on generalization and improvement of the dynamic model are considered and results presented. (author)
Oscillatory periods in the sun and theoretical models with or without mixing
International Nuclear Information System (INIS)
Scuflaire, R.; Gabriel, M.; Noels, A.; Boury, A.
1975-01-01
Theoretical eigenvalues corresponding to periods less than one hour are presented for a standard solar model and for models of about the solar age which are undergoing a thermal pulse following a fast mixing. The two sets of eigenvalues differ very little, the differences being probably less than the accuracy of Hill's observations, except that the standard solar model presents a quadrupolar oscillation with a 43 min period while the mixed models do not. This period does not seem to be present in Hill's observations. (orig./BJ) [de
Status of molten fuel coolant interaction studies and theoretical modelling work at IGCAR
International Nuclear Information System (INIS)
Rao, P.B.; Singh, Om Pal; Singh, R.S.
1994-01-01
The status of Molten Fuel Coolant Interaction (MFCI) studies is reviewed and some of the important observations made are presented. A new model for MFCI that is developed at IGCAR by considering the various mechanisms in detail is described. The model is validated and compared with the available experimental data and theoretical work at different stages of its development. Several parametric studies that are carried using this model are described. The predictions from this model have been found to be satisfactory, considering the complexity of the MFCI. A need for more comprehensive and MFCI-specific experimental tests is brought out. (author)
Directory of Open Access Journals (Sweden)
B.I. Kuznetsov
2015-08-01
Full Text Available The aim of this work is the synthesis of neural network aiming and stabilization system for the special equipment of moving objects with neuro-controller on the basis of standard model and performance comparison of the neural network system with the neural network predictive control. Build a block diagram of the neural network aiming and stabilization system, based on the subject control principle with PD-regulator in the position loop and with neuro-controller on the basis of standard model in the in the velocity loop. The neuro-controller on the basis of standard model Model Reference Controller is synthesized in the MATLAB Neural Network Toolbox and system simulation is performed. The studies show that the transient state variables of the system are oscillatory. Therefore, the neuro-controller with the prediction NN Predictive Controller should be used for aiming and stabilizing system to provide high dynamic characteristics achieved at the cost of higher complexity and computational cost.
Suchkov, V V; Petrovskiĭ, A M; Shkhvatsabaia, I K; Erina, E V; Sidel'nikova, T Ia
1975-04-01
The methods of determining the maximum permissible and functionally justifiable (upper and lower) limits of arterial pressure fluctuations limiting the zones of individual "comfort" "caution" and "alarm" for every patient are described. The mathematical method of the least squares was used for long-term control of the maintenance of arterial pressure within the limits individually pre-set for those treated on an out-patient basis. The above methods permit to decrease the duration of therapy with a minimal drug expenditure and to ensure a mass control of the efficacy of hypotensive therapy.
A THEORETICAL MODEL OF SUPPORTING OPEN SOURCE FRONT END INNOVATION THROUGH IDEA MANAGEMENT
DEFF Research Database (Denmark)
Aagaard, Annabeth
2013-01-01
to overcome these various challenges companies are looking for new models to support FEI. This theoretical paper explores in what way idea management may be applied as a tool in facilitation of front end innovation and how this facilitation may be captured in a conceptual model. First, I show through...... a literature study, how idea management and front end innovation are related and how they may support each other. Secondly, I present a theoretical model of how idea management may be applied in support of the open source front end of new product innovations. Thirdly, I present different venues of further...... exploration of active facilitation of open source front end innovation through idea management....
International Nuclear Information System (INIS)
Ahlroth, S.
2001-01-01
This licentiate thesis tries to bridge the gap between the theoretical and the practical studies in the field of environmental accounting. In the paper, 1 develop an optimal control theory model for adjusting NDP for the effects Of SO 2 and NO x emissions, and subsequently insert empirically estimated values. The model includes correction entries for the effects on welfare, real capital, health and the quality and quantity of renewable natural resources. In the empirical valuation study, production losses were estimated with dose-response functions. Recreational and other welfare values were estimated by the contingent valuation (CV) method. Effects on capital depreciation are also included. For comparison, abatement costs and environmental protection expenditures for reducing sulfur and nitrogen emissions were estimated. The theoretical model was then utilized to calculate the adjustment to NDP in a consistent manner
Energy Technology Data Exchange (ETDEWEB)
Ahlroth, S.
2001-01-01
This licentiate thesis tries to bridge the gap between the theoretical and the practical studies in the field of environmental accounting. In the paper, 1 develop an optimal control theory model for adjusting NDP for the effects Of SO{sub 2} and NO{sub x} emissions, and subsequently insert empirically estimated values. The model includes correction entries for the effects on welfare, real capital, health and the quality and quantity of renewable natural resources. In the empirical valuation study, production losses were estimated with dose-response functions. Recreational and other welfare values were estimated by the contingent valuation (CV) method. Effects on capital depreciation are also included. For comparison, abatement costs and environmental protection expenditures for reducing sulfur and nitrogen emissions were estimated. The theoretical model was then utilized to calculate the adjustment to NDP in a consistent manner.
A bispectral q-hypergeometric basis for a class of quantum integrable models
Baseilhac, Pascal; Martin, Xavier
2018-01-01
For the class of quantum integrable models generated from the q-Onsager algebra, a basis of bispectral multivariable q-orthogonal polynomials is exhibited. In the first part, it is shown that the multivariable Askey-Wilson polynomials with N variables and N + 3 parameters introduced by Gasper and Rahman [Dev. Math. 13, 209 (2005)] generate a family of infinite dimensional modules for the q-Onsager algebra, whose fundamental generators are realized in terms of the multivariable q-difference and difference operators proposed by Iliev [Trans. Am. Math. Soc. 363, 1577 (2011)]. Raising and lowering operators extending those of Sahi [SIGMA 3, 002 (2007)] are also constructed. In the second part, finite dimensional modules are constructed and studied for a certain class of parameters and if the N variables belong to a discrete support. In this case, the bispectral property finds a natural interpretation within the framework of tridiagonal pairs. In the third part, eigenfunctions of the q-Dolan-Grady hierarchy are considered in the polynomial basis. In particular, invariant subspaces are identified for certain conditions generalizing Nepomechie's relations. In the fourth part, the analysis is extended to the special case q = 1. This framework provides a q-hypergeometric formulation of quantum integrable models such as the open XXZ spin chain with generic integrable boundary conditions (q ≠ 1).
Theoretical model of laminar flow in a channel or tube under ocean conditions
International Nuclear Information System (INIS)
Yan, B.H.; Yu, L.; Yang, Y.H.
2011-01-01
Research highlights: → The theoretical model of laminar flow in channels under ocean conditions is established. → The frictional resistance coefficient and Nusselt number are also obtained. → The theoretical results are in agreement with experimental data. → The oscillation of parameters is induced by the tangential force. -- Abstract: The theoretical model of laminar flow in a channel or tube under ocean conditions is established. The velocity and temperature correlations are derived, and the frictional resistance coefficient and Nusselt number are also obtained. The theoretical results are in agreement with experimental data. The oscillation of parameters is induced by the tangential force due to ocean conditions. The effect of centrifugal and Coriolis forces on the flow is negligible. The effects of several parameters on the frictional resistance coefficient and Nusselt number are investigated. The oscillating amplitude of Nusselt number increases with the increasing of Prandtl number. Both the oscillating amplitudes of frictional resistance coefficient and Nusselt number increase with the increasing of rolling frequency.
Directory of Open Access Journals (Sweden)
Juan Carlos Vento Carballea
2010-09-01
Full Text Available The working training needs of the general workers (not teaching staff from the universities of pedagogical sciencies are not common issues in pedagogical research. This article deals with the theoretical grounds of the general workers ́environmental working training, a limited area within the general training these workers from the University of Pedagogical Sciencies “Rafael María de Mendive”, should receive. Such grounds are identified in the philosophy and the sociology of education, the historical-cultural approach by L. S. Vigotski and his followers, the Theory of Advanced Education, and the contents of the environmental education, along with the parameters to qualify an environmentalist educator.
Directory of Open Access Journals (Sweden)
Larysa Slyvka
2017-03-01
Full Text Available On the basis of the analysis of psycological and pedagogical literature the essence of thenotions “healthfocuses environment”, “primary teachers’ training to carry out healthfocusesenvironment”, “primary teachers’ readiness to carry out healthfocuses environment” isspecified. The model of preperation of the students of speciality “Primary Education” tohealthfocuses environment is offered. The totality of knowledge necessary for solvingprofessionally important tasks and realization healthpreserving activity is presented, skills andabilities which are the basis for realization of healthpreserving activity of future teachers insecondary educational establishments are stressed.Key words: health, healthy way of life, younger school-children, future primaryteachers’, healthfocuses environment.
Holley, W. R.; Chatterjee, A.
1996-01-01
We have developed a general theoretical model for the interaction of ionizing radiation with chromatin. Chromatin is modeled as a 30-nm-diameter solenoidal fiber comprised of 20 turns of nucleosomes, 6 nucleosomes per turn. Charged-particle tracks are modeled by partitioning the energy deposition between primary track core, resulting from glancing collisions with 100 eV or less per event, and delta rays due to knock-on collisions involving energy transfers >100 eV. A Monte Carlo simulation incorporates damages due to the following molecular mechanisms: (1) ionization of water molecules leading to the formation of OH, H, eaq, etc.; (2) OH attack on sugar molecules leading to strand breaks: (3) OH attack on bases; (4) direct ionization of the sugar molecules leading to strand breaks; (5) direct ionization of the bases. Our calculations predict significant clustering of damage both locally, over regions up to 40 bp and over regions extending to several kilobase pairs. A characteristic feature of the regional damage predicted by our model is the production of short fragments of DNA associated with multiple nearby strand breaks. The shapes of the spectra of DNA fragment lengths depend on the symmetries or approximate symmetries of the chromatin structure. Such fragments have subsequently been detected experimentally and are reported in an accompanying paper (B. Rydberg, Radiat, Res. 145, 200-209, 1996) after exposure to both high- and low-LET radiation. The overall measured yields agree well quantitatively with the theoretical predictions. Our theoretical results predict the existence of a strong peak at about 85 bp, which represents the revolution period about the nucleosome. Other peaks at multiples of about 1,000 bp correspond to the periodicity of the particular solenoid model of chromatin used in these calculations. Theoretical results in combination with experimental data on fragmentation spectra may help determine the consensus or average structure of the
USING OF BYOD MODEL FOR TESTING OF EDUCATIONAL ACHIEVEMENTS ON THE BASIS OF GOOGLE SEARCH SERVICES
Directory of Open Access Journals (Sweden)
Tetiana Bondarenko
2016-04-01
Full Text Available The technology of using their own mobile devices of learners for testing educational achievements, based on the model of BYOD, in an article is offered. The proposed technology is based on cloud services Google. This technology provides a comprehensive support of testing system: creating appropriate forms, storing the results in cloud storage, processing test results and management of testing system through the use of Google-Calendar. A number of software products based on cloud technologies that allow using BYOD model for testing of educational achievement are described, their strengths and weaknesses are identified. This article also describes the stages of the testing process of the academic achievements of students on the basis of Google search services with using the BYOD model. The proposed approaches to the testing of educational achievements based on using of BYOD model extends the space and time of the testing, makes the test procedure more flexible and systematically, adds to the procedure for testing the elements of a computer game. BYOD model opens up broad prospects for implementation of ICT in all forms of learning process, and particularly in testing of educational achievement in view of the limited computing resources in education
Measuring and Managing Value Co-Creation Process: Overview of Existing Theoretical Models
Directory of Open Access Journals (Sweden)
Monika Skaržauskaitė
2013-08-01
Full Text Available Purpose — the article is to provide a holistic view on concept of value co-creation and existing models for measuring and managing it by conducting theoretical analysis of scientific literature sources targeting the integration of various approaches. Most important and relevant results of the literature study are presented with a focus on changed roles of organizations and consumers. This article aims at contributing theoretically to the research stream of measuring co-creation of value in order to gain knowledge for improvement of organizational performance and enabling new and innovative means of value creation. Design/methodology/approach. The nature of this research is exploratory – theoretical analysis and synthesis of scientific literature sources targeting the integration of various approaches was performed. This approach was chosen due to the absence of established theory on models of co-creation, possible uses in organizations and systematic overview of tools measuring/suggesting how to measure co-creation. Findings. While the principles of managing and measuring co-creation in regards of consumer motivation and involvement are widely researched, little attempt has been made to identify critical factors and create models dealing with organizational capabilities and managerial implications of value co-creation. Systematic analysis of literature revealed a gap not only in empirical research concerning organization’s role in co-creation process, but in theoretical and conceptual levels, too. Research limitations/implications. The limitations of this work as a literature review lies in its nature – the complete reliance on previously published research papers and the availability of these studies. For a deeper understanding of co-creation management and for developing models that can be used in real-life organizations, a broader theoretical, as well as empirical, research is necessary. Practical implications. Analysis of the
Developing a theoretical maintenance model for disordered eating in Type 1 diabetes.
Treasure, J; Kan, C; Stephenson, L; Warren, E; Smith, E; Heller, S; Ismail, K
2015-12-01
According to the literature, eating disorders are an increasing problem for more than a quarter of people with Type 1 diabetes and they are associated with accentuated diabetic complications. The clinical outcomes in this group when given standard eating disorder treatments are disappointing. The Medical Research Council guidelines for developing complex interventions suggest that the first step is to develop a theoretical model. To review existing literature to build a theoretical maintenance model for disordered eating in people with Type 1 diabetes. The literature in diabetes relating to models of eating disorder (Fairburn's transdiagnostic model and the dual pathway model) and food addiction was examined and assimilated. The elements common to all eating disorder models include weight/shape concern and problems with mood regulation. The predisposing traits of perfectionism, low self-esteem and low body esteem and the interpersonal difficulties from the transdiagnostic model are also relevant to diabetes. The differences include the use of insulin mismanagement to compensate for breaking eating rules and the consequential wide variations in plasma glucose that may predispose to 'food addiction'. Eating disorder symptoms elicit emotionally driven reactions and behaviours from others close to the individual affected and these are accentuated in the context of diabetes. The next stage is to test the assumptions within the maintenance model with experimental medicine studies to facilitate the development of new technologies aimed at increasing inhibitory processes and moderating environmental triggers. © 2015 The Authors. Diabetic Medicine © 2015 Diabetes UK.
Directory of Open Access Journals (Sweden)
Yujie Huang
2015-01-01
Full Text Available This paper theoretically investigates interactions between a template and functional monomer required for synthesizing an efficient molecularly imprinted polymer (MIP. We employed density functional theory (DFT to compute geometry, single-point energy, and binding energy (ΔE of an MIP system, where spermidine (SPD and methacrylic acid (MAA were selected as template and functional monomer, respectively. The geometry was calculated by using B3LYP method with 6-31+(d basis set. Furthermore, 6-311++(d, p basis set was used to compute the single-point energy of the above geometry. The optimized geometries at different template to functional monomer molar ratios, mode of bonding between template and functional monomer, changes in charge on natural bond orbital (NBO, and binding energy were analyzed. The simulation results show that SPD and MAA form a stable complex via hydrogen bonding. At 1 : 5 SPD to MAA ratio, the binding energy is minimum, while the amount of transferred charge between the molecules is maximum; SPD and MAA form a stable complex at 1 : 5 molar ratio through six hydrogen bonds. Optimizing structure of template-functional monomer complex, through computational modeling prior synthesis, significantly contributes towards choosing a suitable pair of template-functional monomer that yields an efficient MIP with high specificity and selectivity.
Directory of Open Access Journals (Sweden)
E. A. Degtereva
2016-01-01
Full Text Available The article investigates the features of construction of gravity models, the results of the use of which will allow to identify eff ective ways of Russian foreign policy improvements.Purpose of the article: multigravitatsion development model of Russia's foreign trade, which will identify forward the development of export-import relations in the framework of inter-regional trade area of the Russian Federation, including integration associations such as the EU, BRICS, CIS.Methodology: methodological basis of the study make up scientific methods of cognition, namely, methods of theoretical generalization and comparison; method of integrated and structural analysis.Results: During the studied analyzed Russia's foreign trade turnover, the results of which revealed that for the country's economic development is important as a variety of trade fl ows and capital fl ows, which in turn updates the problem of formation and development of the national foreign trade potential, finding the optimal proportion of commodity structure diversification and the introduction of eff ective mechanisms of regulation of export-import operations. The solution of the problem determined the conduct of the study articles Russian contemporary maps of foreign cooperation in the conditions of existing sanctions and embargoes, as well as the identification of targeted country markets for Russia's non-oil exports with a separate allocation problem area that emerged as a result of external challenges of political and economic nature faced by Russia because of the military confl ict in Ukraine. Special attention is paid to the distribution of Russian imports by partner countries.Significance: the example of EU integration associations of the CIS and the BRICS, which make up multiregional commercial space of Russia, multigravitatsionnaya model is constructed in order to assess the impact of Russia's cooperation with the EU member countries, CIS countries and the BRICS, as well as
Advancing Women Scientists: Exploring a Theoretically Grounded Climate Change Workshop Model
Silver, Barbara; Prochaska, Janice; Mederer, Helen; Harlow, Lisa; Sherman, Karen
Universities in the United States have an increasing need to recruit the best and the brightest faculty to remain globally competitive, but the majority of schools share a profile that includes a low percentage of women in most of the science, technology, engineering, and math (STEM) disciplines. Changes in university culture are needed to enable departmental diversity growth, to expand offerings and perspectives, and to strengthen the view that STEM is an attractive choice for female students and prospective faculty. This paper describes the theoretical models used to develop a prototype workshop series implemented in departments to help faculty progress in their readiness to advance women scientists, defined as collaborating, mentoring, sharing resources, and generating support through community. The three theoretical underpinnings are the gender-as-structure theory of organizational change, Appreciative Inquiry, and the Transtheoretical Model. These workshops are one aspect of the climate change efforts implemented by the ADVANCE program of the University of Rhode Island.
International Nuclear Information System (INIS)
Sharma, Suresh C.; Gupta, Neha
2015-01-01
A theoretical modeling for the catalyst-assisted growth of graphene sheet in the presence of plasma has been investigated. It is observed that the plasma parameters can strongly affect the growth and field emission properties of graphene sheet. The model developed accounts for the charging rate of the graphene sheet; number density of electrons, ions, and neutral atoms; various elementary processes on the surface of the catalyst nanoparticle; surface diffusion and accretion of ions; and formation of carbon-clusters and large graphene islands. In our investigation, it is found that the thickness of the graphene sheet decreases with the plasma parameters, number density of hydrogen ions and RF power, and consequently, the field emission of electrons from the graphene sheet surface increases. The time evolution of the height of graphene sheet with ion density and sticking coefficient of carbon species has also been examined. Some of our theoretical results are in compliance with the experimental observations
A Theoretical Bayesian Game Model for the Vendor-Retailer Relation
Directory of Open Access Journals (Sweden)
Emil CRIŞAN
2012-06-01
Full Text Available We consider an equilibrated supply chain with two equal partners, a vendor and a retailer (also called newsboy type products supply chain. The actions of each partner are driven by profit. Given the fact that at supply chain level are specific external influences which affect the costs and concordant the profit, we use a game theoretic model for the situation, considering costs and demand. At theoretical level, symmetric and asymmetric information patterns are considered for this situation. There are at every supply chain’s level situations when external factors (such as inflation, raw-material rate influence the situation of each partner even if the information is well shared within the chain. The model we propose considers both the external factors and asymmetric information within a supply chain.
International Nuclear Information System (INIS)
Dorofeeva, Olga V.; Ryzhova, Oxana N.
2009-01-01
The standard molar enthalpies of formation of urea, glycine, and L-alanine in the gaseous phase at 298.15 K were calculated by the high-level Gaussian-3X method. The agreement with the available experimental data is very good for urea and glycine and, thus, supports the high accuracy of calculated values. A significant discrepancy between theoretical and experimental enthalpy of formation values for L-alanine provides a reason to reconsider the experimental data previously used to derive the standard molar enthalpy of formation of L-alanine in the gaseous phase at 298.15 K. To obtain a more reliable value of enthalpy of sublimation at 298.15 K, the heat capacity values of gaseous L-alanine were calculated by standard statistical thermodynamics formulae using molecular parameters determined from B3LYP/cc-pVTZ calculations. With the obtained value of C p,m 0 (L-alanine, g, 298.15 K) = 112.6 ± 4.0 J . K -1 . mol -1 the original published experimental values of enthalpy of sublimation of L-alanine were readjusted to the reference temperature: Δ cr g H m (L-alanine, 298.15 K) = 135.2 ± 2.0 kJ . mol -1 . This value, together with the experimental enthalpy of formation of solid L-alanine, Δ f H m 0 (L-alanine, cr, 298.15 K) = -560.0 ± 1.0 kJ . mol -1 [S.N. Ngauv, R. Sabbah, M. Laffitte, Thermochim. Acta 20 (1977) 371-380; I. Contineanu, D.I. Marchidan, Rev. Roum. Chim. 29 (1984) 43-48], gives a new value for the enthalpy of formation of L-alanine in the gaseous phase, Δ f H m 0 (L-alanine, g, 298.15 K) = -424.8 ± 2.0 kJ . mol -1 , which is in good agreement with our theoretical G3X result, -427.6 ± 4.0 kJ . mol -1 . The same procedure for glycine allowed us to improve the literature value of the enthalpy of formation for this compound, Δ f H m 0 (glycine, g, 298.15 K) = -393.7 ± 1.5 kJ . mol -1 . As a result a set of self-consistent thermochemical data for glycine and L-alanine is proposed
Model of Forecasting the Social News Events on the Basis of Stochastic Dynamics Methods
Directory of Open Access Journals (Sweden)
Zhukov D.O.
2017-01-01
Full Text Available For a description of the information space it is introduced a vector representation of the constituent text documents that are bound by the events described in the timeline. The predicted event is also represented by a vector obtained on the base of its text description. The mean value of projections of the information space in the direction of the vector of predicted events at different time points is considered as a set of information system states. It is also entered the change values of states. To describe transitions between states is used a probabilistic approach and the difference transition scheme. This makes it possible to get the dependence of the time for the value of the probability density for the event “detection information system in a state” in the form of a second order differential equation. On the basis of this equation is formulated and solved the boundary problem. Carried out by the authors the analysis of the stochastic dynamics of achievement a threshold of realization of news events has allowed the establishing of the ability to increase the probability of transition almost simultaneously with the beginning of the process of the news cluster structure changing. This is due to the presence of the memory of previous states in the information system and the possibility of self-description, as a result of accounting in the differential model information processes on the basis of the second derivative over time. In addition, the proposed model demonstrates the possibility of sudden changes in the probability of crossing the threshold of events and takes into account the presence of oscillations in her behavior. Based on the model developed it is proposed the algorithm for analysis of news clusters relationship in the information field with the possibility of occurrence of the predicted event, and determined the possible time of its implementation.
Dou, Kaili; Yu, Ping; Deng, Ning; Liu, Fang; Guan, YingPing; Li, Zhenye; Ji, Yumeng; Du, Ningkai; Lu, Xudong; Duan, Huilong
2017-01-01
Background Chronic disease patients often face multiple challenges from difficult comorbidities. Smartphone health technology can be used to help them manage their conditions only if they accept and use the technology. Objective The aim of this study was to develop and test a theoretical model to predict and explain the factors influencing patients’ acceptance of smartphone health technology for chronic disease management. Methods Multiple theories and factors that may influence patients’ acc...
Experimental and theoretical model of a concentrating photovoltaic and thermal system
International Nuclear Information System (INIS)
Renno, C.; Petito, F.
2016-01-01
Highlights: • Experimental analysis of a concentrating photovoltaic system. • MJ cell electrical characterization and concentration factor evaluation. • Thermal model in ANSYS of the CPV/T system cooling circuit. - Abstract: The experimental and theoretical analysis of a concentrating photovoltaic and thermal system (CPV/T) presented in this paper allows to evaluate the electrical parameters of the system, the concentration factor, the cell temperature in different working conditions and the fluid temperature. In particular, the experimental values of the cell temperature represent the input of a model developed in ANSYS-CFX. This model evaluates the theoretical temperature values of the fluid that flows into the cooling circuit of the CPV/T system, designed with the CATIA software. Hence, both electrical and thermal parameters have been analyzed in order to evaluate the potential energy production of a concentrating photovoltaic and thermal system. Different configurations of the CPV/T system have been analyzed and the value of the concentration factor has been determined by means of an experimental procedure. The experimental and theoretical electric powers are compared in different climatic conditions considering a solar radiation included between 500 and 900 W/m 2 . The electric efficiency is also evaluated as function of solar irradiance and cloudiness. Moreover, the fluid temperature as function of the experimental cell temperature is determined in different working conditions by means of the ANSYS model. The fluid temperature is also theoretically determined varying the operating conditions along the circuit. Finally, a study of the electrical and thermal performances represents a key-factor to develop a more complex prototype of a CPV/T system.
The neural mediators of kindness-based meditation: a theoretical model
Mascaro, Jennifer S.; Darcher, Alana; Negi, Lobsang T.; Raison, Charles L.
2015-01-01
Although kindness-based contemplative practices are increasingly employed by clinicians and cognitive researchers to enhance prosocial emotions, social cognitive skills, and well-being, and as a tool to understand the basic workings of the social mind, we lack a coherent theoretical model with which to test the mechanisms by which kindness-based meditation may alter the brain and body. Here, we link contemplative accounts of compassion and loving-kindness practices with research from social c...
The neural mediators of kindness-based meditation: a theoretical model
Jennifer Streiffer Mascaro; Jennifer Streiffer Mascaro; Alana eDarcher; Lobsang Tenzin Negi; Charles eRaison; Charles eRaison
2015-01-01
Although kindness-based contemplative practices are increasingly employed by clinicians and cognitive researchers to enhance prosocial emotions, social cognitive skills, and well-being, and as a tool to understand the basic workings of the social mind, we lack a coherent theoretical model with which to test the mechanisms by which kindness-based meditation may alter the brain and body. Here we link contemplative accounts of compassion and loving-kindness practices with research from social co...
Wielicki, B. A. (Principal Investigator); Barkstrom, B. R. (Principal Investigator); Charlock, T. P.; Baum, B. A.; Green, R. N.; Minnis, P.; Smith, G. L.; Coakley, J. A.; Randall, D. R.; Lee, R. B., III
1995-01-01
The theoretical bases for the Release 1 algorithms that will be used to process satellite data for investigation of the Clouds and Earth's Radiant Energy System (CERES) are described. The architecture for software implementation of the methodologies is outlined. Volume 2 details the techniques used to geolocate and calibrate the CERES scanning radiometer measurements of shortwave and longwave radiance to invert the radiances to top-of-the-atmosphere (TOA) and surface fluxes following the Earth Radiation Budget Experiment (ERBE) approach, and to average the fluxes over various time and spatial scales to produce an ERBE-like product. Spacecraft ephemeris and sensor telemetry are used with calibration coefficients to produce a chronologically ordered data product called bidirectional scan (BDS) radiances. A spatially organized instrument Earth scan product is developed for the cloud-processing subsystem. The ERBE-like inversion subsystem converts BDS radiances to unfiltered instantaneous TOA and surface fluxes. The TOA fluxes are determined by using established ERBE techniques. Hourly TOA fluxes are computed from the instantaneous values by using ERBE methods. Hourly surface fluxes are estimated from TOA fluxes by using simple parameterizations based on recent research. The averaging process produces daily, monthly-hourly, and monthly means of TOA and surface fluxes at various scales. This product provides a continuation of the ERBE record.
Papadopoulou, Vasiliki; Valsami, Georgia; Dokoumetzidis, Aristides; Macheras, Panos
2008-09-01
The aim of this work is to develop biopharmaceutics classification systems for new molecular entities (BCS-NMEs) and marketed drugs (BCS-MD). The kinetics of gastrointestinal (GI) wall permeation and dissolution were re-considered theoretically. The relationships between the solubility/dose ratio and the fractions of dose dissolved and absorbed, were also examined. Mean time calculations for drug dissolution (MDT) and permeation (MPT) of the GI wall were analyzed in respect to the mean intestinal transit time (MITT) to identify a cutoff point for drug dissolution and GI wall permeation. Dissolution experiments for marketed drugs were carried out. NMEs were classified into four classes of BCS-NMEs, based on solubility/dose ratio and apparent permeability estimates. A physiologically based cutoff time point for dissolution and permeation was used to differentiate rapidly from slowly dissolving-permeating marketed drugs, which were classified into four classes of BCS-MD using their dissolution index (DI=MITT/MDT) and permeation index (PI=MITT/MPT) values as follows: I (DI>or=3, PI>or=3), II (DIor=3), III (DI>or=3, PI<3) and IV (DI<3, PI<3). In conclusion, two classification systems were developed, one for NMEs based on solubility/dose ratio and permeability estimates and one for marketed drugs based on MDT and MPT estimates.
Directory of Open Access Journals (Sweden)
Misganaw Abebe
2017-11-01
Full Text Available Springback in multi-point dieless forming (MDF is a common problem because of the small deformation and blank holder free boundary condition. Numerical simulations are widely used in sheet metal forming to predict the springback. However, the computational time in using the numerical tools is time costly to find the optimal process parameters value. This study proposes radial basis function (RBF to replace the numerical simulation model by using statistical analyses that are based on a design of experiment (DOE. Punch holding time, blank thickness, and curvature radius are chosen as effective process parameters for determining the springback. The Latin hypercube DOE method facilitates statistical analyses and the extraction of a prediction model in the experimental process parameter domain. Finite element (FE simulation model is conducted in the ABAQUS commercial software to generate the springback responses of the training and testing samples. The genetic algorithm is applied to find the optimal value for reducing and compensating the induced springback for the different blank thicknesses using the developed RBF prediction model. Finally, the RBF numerical result is verified by comparing with the FE simulation result of the optimal process parameters and both results show that the springback is almost negligible from the target shape.
Directory of Open Access Journals (Sweden)
Ruslan Skrynkovskyy
2017-12-01
Full Text Available The purpose of the article is to improve the model of the enterprise (institution, organization management process on the basis of general management functions. The graphic model of the process of management according to the process-structured management is presented. It has been established that in today's business environment, the model of the management process should include such general management functions as: 1 controlling the achievement of results; 2 planning based on the main goal; 3 coordination and corrective actions (in the system of organization of work and production; 4 action as a form of act (conscious, volitional, directed; 5 accounting system (accounting, statistical, operational-technical and managerial; 6 diagnosis (economic, legal with such subfunctions as: identification of the state and capabilities; analysis (economic, legal, systemic with argumentation; assessment of the state, trends and prospects of development. The prospect of further research in this direction is: 1 the formation of a system of interrelation of functions and management methods, taking into account the presented research results; 2 development of the model of effective and efficient communication business process of the enterprise.
Yousefi, Bardia; Loo, Chu Kiong
2014-01-01
Following the study on computational neuroscience through functional magnetic resonance imaging claimed that human action recognition in the brain of mammalian pursues two separated streams, that is, dorsal and ventral streams. It follows up by two pathways in the bioinspired model, which are specialized for motion and form information analysis (Giese and Poggio 2003). Active basis model is used to form information which is different from orientations and scales of Gabor wavelets to form a dictionary regarding object recognition (human). Also biologically movement optic-flow patterns utilized. As motion information guides share sketch algorithm in form pathway for adjustment plus it helps to prevent wrong recognition. A synergetic neural network is utilized to generate prototype templates, representing general characteristic form of every class. Having predefined templates, classifying performs based on multitemplate matching. As every human action has one action prototype, there are some overlapping and consistency among these templates. Using fuzzy optical flow division scoring can prevent motivation for misrecognition. We successfully apply proposed model on the human action video obtained from KTH human action database. Proposed approach follows the interaction between dorsal and ventral processing streams in the original model of the biological movement recognition. The attained results indicate promising outcome and improvement in robustness using proposed approach.
Theoretical modeling and experimental analysis of solar still integrated with evacuated tubes
Panchal, Hitesh; Awasthi, Anuradha
2017-06-01
In this present research work, theoretical modeling of single slope, single basin solar still integrated with evacuated tubes has been performed based on energy balance equations. Major variables like water temperature, inner glass cover temperature and distillate output has been computed based on theoretical modeling. The experimental setup has been made from locally available materials and installed at Gujarat Power Engineering and Research Institute, Mehsana, Gujarat, India (23.5880°N, 72.3693°E) with 0.04 m depth during 6 months of time interval. From the series of experiments, it is found considerable increment in average distillate output of a solar still when integrated with evacuated tubes not only during daytime but also from night time. In all experimental cases, the correlation of coefficient (r) and root mean square percentage deviation of theoretical modeling and experimental study found good agreement with 0.97 < r < 0.98 and 10.22 < e < 38.4% respectively.
The interacting gaps model: reconciling theoretical and numerical approaches to limit-order models
Czech Academy of Sciences Publication Activity Database
Muchnik, L.; Slanina, František; Solomon, S.
2003-01-01
Roč. 330, - (2003), s. 232-239 ISSN 0378-4371 R&D Projects: GA ČR GA202/01/1091 Institutional research plan: CEZ:AV0Z1010914 Keywords : stochastic processes * econophysics Subject RIV: BE - Theoretical Physics Impact factor: 1.180, year: 2003
Anken, R. H.; Rahmann, H.
One hypothesis for the explanation of the so-called ``loop-swimming'' behaviour in fish when being subjected to reduced gravity assumes that the activities of the differently weighted otoliths of the two labyrinths are well compensated on ground but that a functional asymmetry is induced in weightlessness, resulting in a tonus asymmetry of the body and by this generating the ``loop-swimming'' behaviour. The basis of this abnormal behaviour has to be searched for in the central nervous system (cns), where the signal-transduction from the inner ear- related signal internalisation to the signal response takes place. Circuits within the CNS of fish, that could possibly generate the ``loop-swimming'', might be as follows: An asymmetric activation of vestibulospinal circuits would directly result in a tonus asymmetry of the body. An asymmetric activation of the oculomotor nucleus would generate an asymmetrical rotation of the eyes. This would cause in its turn asymmetric images on the two retinas, which were forwarded to the diencephalic accessory optic system (AOS). It is the task of the AOS to stabilize retinal images, thereby involving the cerebellum, which is the main integration center for sensory and motor modalities. With this, the cerebellar output would generate a tonus asymmetry of the body in order to make the body of the fish follow its eyes. Such movements (especially when assuming an open loop control) would end up in the aforementioned ``loop-swimming'' behaviour.
Radial basis functions in mathematical modelling of flow boiling in minichannels
Directory of Open Access Journals (Sweden)
Hożejowska Sylwia
2017-01-01
Full Text Available The paper addresses heat transfer processes in flow boiling in a vertical minichannel of 1.7 mm depth with a smooth heated surface contacting fluid. The heated element for FC-72 flowing in a minichannel was a 0.45 mm thick plate made of Haynes-230 alloy. An infrared camera positioned opposite the central, axially symmetric part of the channel measured the plate temperature. K-type thermocouples and pressure converters were installed at the inlet and outlet of the minichannel. In the study radial basis functions were used to solve a problem concerning heat transfer in a heated plate supplied with the controlled direct current. According to the model assumptions, the problem is treated as twodimensional and governed by the Poisson equation. The aim of the study lies in determining the temperature field and the heat transfer coefficient. The results were verified by comparing them with those obtained by the Trefftz method.
A two-dimensional volatility basis set – Part 3: Prognostic modeling and NOx dependence
Directory of Open Access Journals (Sweden)
W. K. Chuang
2016-01-01
Full Text Available When NOx is introduced to organic emissions, aerosol production is sometimes, but not always, reduced. Under certain conditions, these interactions will instead increase aerosol concentrations. We expanded the two-dimensional volatility basis set (2D-VBS to include the effects of NOx on aerosol formation. This includes the formation of organonitrates, where the addition of a nitrate group contributes to a decrease of 2.5 orders of magnitude in volatility. With this refinement, we model outputs from experimental results, such as the atomic N : C ratio, organonitrate mass, and nitrate fragments in Aerosol Mass Spectrometer (AMS measurements. We also discuss the mathematical methods underlying the implementation of the 2D-VBS and provide the complete code in the Supplement. A developer version is available on Bitbucket, an online community repository.
Modeling of Hydraulic Fracturing on the Basis of the Particle Method
Berezhnoi, D. V.; Gabsalikova, N. F.; Izotov, V. G.; Miheev, V. V.
2018-01-01
A technique of calculating the deformation of the soil environment when it interacts with a liquid on the basis of the particle method a is realized. To describe the behavior of the solid and liquid phases of the soil, a classical two-parameter Lennard-Jones interaction potential and its modified version proposed by the authors were chosen. The model problem of deformation and partial destruction of a soil massif under strong pressure from the liquid pumped into it is solved. Analysis of the results shows that the use of the modified Lennard-Jones potential for describing the solid phase of the soil environment makes it possible to describe the process of formation of cracks in the soil during hydraulic fracturing of the formation.
Marasulov, Akhmat; Saipov, Amangeldi; ?rymbayeva, Kulimkhan; Zhiyentayeva, Begaim; Demeuov, Akhan; Konakbaeva, Ulzhamal; Bekbolatova, Akbota
2016-01-01
The aim of the study is to examine the methodological-theoretical construction bases for development mechanism of an integrated model for a specialist's training and teacher's conceptual-theoretical activity. Using the methods of generalization of teaching experience, pedagogical modeling and forecasting, the authors determine the urgent problems…
Mello, Claudio V
2014-10-23
Songbirds are capable of learning their vocalizations by copying a singing adult. This vocal learning ability requires juveniles to hear and memorize the sound of the adult song, and later to imitate it through a process involving sensorimotor integration. Vocal learning is a trait that songbirds share with humans, where it forms the basis of spoken language acquisition, with other avian groups (parrots and hummingbirds), and with a few other mammals (cetaceans, bats). It is however absent in traditional model organisms such as rodents and nonhuman primates. Zebra finches, a songbird species from Australia, are popular pets and are easy to breed. They also sing a relatively simple and stereotyped song that is amenable to quantitative analysis. Zebra finches have thus emerged as a choice model organism for investigating the neurobiological basis of vocal learning. A number of tools and methodologies have been developed to characterize the bioacoustics properties of their song, analyze the degree of accurate copying during vocal learning, map the brain circuits that control singing and song learning, and investigate the physiology of these circuits. Such studies have led to a large base of knowledge on song production and learning, and their underlying neural substrate. Several molecular resources have recently become available, including brain cDNA/EST databases, microarrays, BAC libraries, a molecular brain atlas, a complete genome assembly, and the ability to perform transgenesis. The recent availability of many other avian genomes provides unique opportunities for comparative analysis in the search for features unique to vocal learning organisms. © 2014 Cold Spring Harbor Laboratory Press.
Modeling transit bus fuel consumption on the basis of cycle properties.
Delgado, Oscar F; Clark, Nigel N; Thompson, Gregory J
2011-04-01
A method exists to predict heavy-duty vehicle fuel economy and emissions over an "unseen" cycle or during unseen on-road activity on the basis of fuel consumption and emissions data from measured chassis dynamometer test cycles and properties (statistical parameters) of those cycles. No regression is required for the method, which relies solely on the linear association of vehicle performance with cycle properties. This method has been advanced and examined using previously published heavy-duty truck data gathered using the West Virginia University heavy-duty chassis dynamometer with the trucks exercised over limited test cycles. In this study, data were available from a Washington Metropolitan Area Transit Authority emission testing program conducted in 2006. Chassis dynamometer data from two conventional diesel buses, two compressed natural gas buses, and one hybrid diesel bus were evaluated using an expanded driving cycle set of 16 or 17 different driving cycles. Cycle properties and vehicle fuel consumption measurements from three baseline cycles were selected to generate a linear model and then to predict unseen fuel consumption over the remaining 13 or 14 cycles. Average velocity, average positive acceleration, and number of stops per distance were found to be the desired cycle properties for use in the model. The methodology allowed for the prediction of fuel consumption with an average error of 8.5% from vehicles operating on a diverse set of chassis dynamometer cycles on the basis of relatively few experimental measurements. It was found that the data used for prediction should be acquired from a set that must include an idle cycle along with a relatively slow transient cycle and a relatively high speed cycle. The method was also applied to oxides of nitrogen prediction and was found to have less predictive capability than for fuel consumption with an average error of 20.4%.
Darmon, David
2018-03-01
In the absence of mechanistic or phenomenological models of real-world systems, data-driven models become necessary. The discovery of various embedding theorems in the 1980s and 1990s motivated a powerful set of tools for analyzing deterministic dynamical systems via delay-coordinate embeddings of observations of their component states. However, in many branches of science, the condition of operational determinism is not satisfied, and stochastic models must be brought to bear. For such stochastic models, the tool set developed for delay-coordinate embedding is no longer appropriate, and a new toolkit must be developed. We present an information-theoretic criterion, the negative log-predictive likelihood, for selecting the embedding dimension for a predictively optimal data-driven model of a stochastic dynamical system. We develop a nonparametric estimator for the negative log-predictive likelihood and compare its performance to a recently proposed criterion based on active information storage. Finally, we show how the output of the model selection procedure can be used to compare candidate predictors for a stochastic system to an information-theoretic lower bound.
International Nuclear Information System (INIS)
Mardinoglu, Adil; Cregg, P.J.; Murphy, Kieran; Curtin, Maurice; Prina-Mello, Adriele
2011-01-01
The magnetisable stent assisted magnetic targeted drug delivery system in a physiologically stretched vessel is considered theoretically. The changes in the mechanical behaviour of the vessel are analysed under the influence of mechanical forces generated by blood pressure. In this 2D mathematical model a ferromagnetic, coiled wire stent is implanted to aid collection of magnetic drug carrier particles in an elastic tube, which has similar mechanical properties to the blood vessel. A cyclic mechanical force is applied to the elastic tube to mimic the mechanical stress and strain of both the stent and vessel while in the body due to pulsatile blood circulation. The magnetic dipole-dipole and hydrodynamic interactions for multiple particles are included and agglomeration of particles is also modelled. The resulting collection efficiency of the mathematical model shows that the system performance can decrease by as much as 10% due to the effects of the pulsatile blood circulation. - Research highlights: →Theoretical modelling of magnetic drug targeting on a physiologically stretched stent-vessel system. →Cyclic mechanical force applied to mimic the mechanical stress and strain of both stent and vessel. →The magnetic dipole-dipole and hydrodynamic interactions for multiple particles is modelled. →Collection efficiency of the mathematical model is calculated for different physiological blood flow and magnetic field strength.
Theoretical and experimental stress analyses of ORNL thin-shell cylinder-to-cylinder model 3
International Nuclear Information System (INIS)
Gwaltney, R.C.; Bolt, S.E.; Corum, J.M.; Bryson, J.W.
1975-06-01
The third in a series of four thin-shell cylinder-to-cylinder models was tested, and the experimentally determined elastic stress distributions were compared with theoretical predictions obtained from a thin-shell finite-element analysis. The models are idealized thin-shell structures consisting of two circular cylindrical shells that intersect at right angles. There are no transitions, reinforcements, or fillets in the junction region. This series of model tests serves two basic purposes: the experimental data provide design information directly applicable to nozzles in cylindrical vessels; and the idealized models provide test results for use in developing and evaluating theoretical analyses applicable to nozzles in cylindrical vessels and to thin piping tees. The cylinder of model 3 had a 10 in. OD and the nozzle had a 1.29 in. OD, giving a d 0 /D 0 ratio of 0.129. The OD/thickness ratios for the cylinder and the nozzle were 50 and 7.68 respectively. Thirteen separate loading cases were analyzed. In each, one end of the cylinder was rigidly held. In addition to an internal pressure loading, three mutually perpendicular force components and three mutually perpendicular moment components were individually applied at the free end of the cylinder and at the end of the nozzle. The experimental stress distributions for all the loadings were obtained using 158 three-gage strain rosettes located on the inner and outer surfaces. The loading cases were also analyzed theoretically using a finite-element shell analysis developed at the University of California, Berkeley. The analysis used flat-plate elements and considered five degrees of freedom per node in the final assembled equations. The comparisons between theory and experiment show reasonably good agreement for this model. (U.S.)
Theoretical and experimental stress analyses of ORNL thin-shell cylinder-to-cylinder model 4
International Nuclear Information System (INIS)
Gwaltney, R.C.; Bolt, S.E.; Bryson, J.W.
1975-06-01
The last in a series of four thin-shell cylinder-to-cylinder models was tested, and the experimentally determined elastic stress distributions were compared with theoretical predictions obtained from a thin-shell finite-element analysis. The models in the series are idealized thin-shell structures consisting of two circular cylindrical shells that intersect at right angles. There are no transitions, reinforcements, or fillets in the junction region. This series of model tests serves two basic purposes: (1) the experimental data provide design information directly applicable to nozzles in cylindrical vessels, and (2) the idealized models provide test results for use in developing and evaluating theoretical analyses applicable to nozzles in cylindrical vessels and to thin piping tees. The cylinder of model 4 had an outside diameter of 10 in., and the nozzle had an outside diameter of 1.29 in., giving a d 0 /D 0 ratio of 0.129. The OD/thickness ratios were 50 and 20.2 for the cylinder and nozzle respectively. Thirteen separate loading cases were analyzed. For each loading condition one end of the cylinder was rigidly held. In addition to an internal pressure loading, three mutually perpendicular force components and three mutually perpendicular moment components were individually applied at the free end of the cylinder and at the end of the nozzle. The experimental stress distributions for each of the 13 loadings were obtained using 157 three-gage strain rosettes located on the inner and outer surfaces. Each of the 13 loading cases was also analyzed theoretically using a finite-element shell analysis developed at the University of California, Berkeley. The analysis used flat-plate elements and considered five degrees of freedom per node in the final assembled equations. The comparisons between theory and experiment show reasonably good agreement for this model. (U.S.)
A theoretical model of co-worker responses to work reintegration processes.
Dunstan, Debra A; Maceachen, Ellen
2014-06-01
Emerging research has shown that co-workers have a significant influence on the return-to-work outcomes of partially fit ill or injured employees. By drawing on theoretical findings from the human resource and wider behavioral sciences literatures, our goal was to formulate a theoretical model of the influences on and outcomes of co-worker responses within work reintegration. From a search of 15 data bases covering the social sciences, business and medicine, we identified articles containing models of the factors that influence co-workers' responses to disability accommodations; and, the nature and impact of co-workers' behaviors on employee outcomes. To meet our goal, we combined identified models to form a comprehensive model of the relevant factors and relationships. Internal consistency and externally validity were assessed. The combined model illustrates four key findings: (1) co-workers' behaviors towards an accommodated employee are influenced by attributes of that employee, the illness or injury, the co-worker themselves, and the work environment; (2) the influences-behaviour relationship is mediated by perceptions of the fairness of the accommodation; (3) co-workers' behaviors affect all work reintegration outcomes; and (4) co-workers' behaviours can vary from support to antagonism and are moderated by type of support required, the social intensity of the job, and the level of antagonism. Theoretical models from the wider literature are useful for understanding the impact of co-workers on the work reintegration process. To achieve optimal outcomes, co-workers need to perceive the arrangements as fair. Perceptions of fairness might be supported by co-workers' collaborative engagement in the planning, monitoring and review of work reintegration activities.
Elhorst, J. Paul
2001-01-01
This paper attempts to provide an integrated overview of theoretical and empirical explanations used in the applied literature on regional unemployment differentials. On the basis of 41 empirical studies, four different model types covering nine theoretical constructs of regional unemployment
Team Resilience as a Second-Order Emergent State: A Theoretical Model and Research Directions
Directory of Open Access Journals (Sweden)
Clint Bowers
2017-08-01
Full Text Available Resilience has been recognized as an important phenomenon for understanding how individuals overcome difficult situations. However, it is not only individuals who face difficulties; it is not uncommon for teams to experience adversity. When they do, they must be able to overcome these challenges without performance decrements.This manuscript represents a theoretical model that might be helpful in conceptualizing this important construct. Specifically, it describes team resilience as a second-order emergent state. We also include research propositions that follow from the model.
Seeling, Walter; Plischke, Max; de Bruin, Jeroen S; Schuh, Christian
2015-01-01
Immunosuppressive therapy is a risky necessity after a patient received a kidney transplant. To reduce risks, a knowledge-based system was developed that determines the right dosage of the immunosuppresive agent Tacrolimus. A theoretical model, to classify medication blood levels as well as medication adaptions, was created using data from almost 500 patients, and over 13.000 examinations. This model was then translated into an Arden Syntax knowledge base, and integrated directly into the hospital information system of the Vienna General Hospital. In this paper we give an overview of the construction and integration of such a system.
The dynamics of the nuclear disassembly in a field-theoretical model at finite entropies
International Nuclear Information System (INIS)
Knoll, J.; Strack, B.
1984-10-01
The expansion phase of a hot nuclear system as created in an energetic heavy-ion collision is calculated and discussed by a selfconsistent field-theoretical model. Dynamical instabilities arising during the expansion from strong fluctuations of the one-body density are included explicitely. First multiplicity distributions and mass spectra resulting from a series of numerical runs in a 2+1 dimensional model world are presented. The dependence of break-up dynamics both on the properties of the binding force and possible correlations in the initially compressed hot state are discussed. (orig.)
A theoretical and empirical evaluation and extension of the Todaro migration model.
Salvatore, D
1981-11-01
"This paper postulates that it is theoretically and empirically preferable to base internal labor migration on the relative difference in rural-urban real income streams and rates of unemployment, taken as separate and independent variables, rather than on the difference in the expected real income streams as postulated by the very influential and often quoted Todaro model. The paper goes on to specify several important ways of extending the resulting migration model and improving its empirical performance." The analysis is based on Italian data. excerpt
Dou, Kaili; Yu, Ping; Deng, Ning; Liu, Fang; Guan, YingPing; Li, Zhenye; Ji, Yumeng; Du, Ningkai; Lu, Xudong; Duan, Huilong
2017-12-06
Chronic disease patients often face multiple challenges from difficult comorbidities. Smartphone health technology can be used to help them manage their conditions only if they accept and use the technology. The aim of this study was to develop and test a theoretical model to predict and explain the factors influencing patients' acceptance of smartphone health technology for chronic disease management. Multiple theories and factors that may influence patients' acceptance of smartphone health technology have been reviewed. A hybrid theoretical model was built based on the technology acceptance model, dual-factor model, health belief model, and the factors identified from interviews that might influence patients' acceptance of smartphone health technology for chronic disease management. Data were collected from patient questionnaire surveys and computer log records about 157 hypertensive patients' actual use of a smartphone health app. The partial least square method was used to test the theoretical model. The model accounted for .412 of the variance in patients' intention to adopt the smartphone health technology. Intention to use accounted for .111 of the variance in actual use and had a significant weak relationship with the latter. Perceived ease of use was affected by patients' smartphone usage experience, relationship with doctor, and self-efficacy. Although without a significant effect on intention to use, perceived ease of use had a significant positive influence on perceived usefulness. Relationship with doctor and perceived health threat had significant positive effects on perceived usefulness, countering the negative influence of resistance to change. Perceived usefulness, perceived health threat, and resistance to change significantly predicted patients' intentions to use the technology. Age and gender had no significant influence on patients' acceptance of smartphone technology. The study also confirmed the positive relationship between intention to use
Stress mediation in caregivers of cognitively impaired adults: theoretical model testing.
Irvin, B L; Acton, G J
1996-01-01
The purpose of the study was to test a midrange model of caregiver stress mediation based on Modeling and Role-Modelpan>ing theory. Perceived support and self-worth were examined to determine if these self-care resources had a mediating effect between stress and well-being in caregivers of cognitively impaired adults. The sample of 117 caregivers completed measures of basic need status, perceived support, self-worth, stress, and well-being. There were significant correlations among the study variables in the expected directions. Resources mediated the relationship between stress and well-being, providing tentative support for theoretically proposed linkages.
Dute, Denise Jantine; Bemelmans, Wanda Jose Erika; Breda, João
2016-05-05
European adolescents and students tend to have low levels of physical activity and eat unhealthy foods, and the prevalence of overweight and obesity has increased, which poses a public health challenge. Mobile apps play an important role in their daily lives, suggesting their potential to be used in health-promoting strategies. This review aimed to explore how mobile apps can contribute to the promotion of healthy nutrition, physical activity, and prevention of overweight in adolescents and students. For the apps identified, the review describes the content, the theoretical mechanisms applied, and lessons learned. The databases Scopus, MEDLINE, Embase, and PsycINFO were searched for English-language publications from January 2009 to November 2013. Studies were included if (1) the primary component of the intervention involves an app; (2) the intervention targets healthy nutrition, or physical activity, or overweight prevention; and (3) the target group included adolescents or students (aged 12-25 years). A total of 15 studies were included, which describe 12 unique apps. Ten of these apps functioned as monitoring tools for assessing dietary intake or physical activity levels. The other apps used a Web-based platform to challenge users to exercise and to allow users to list and photograph their problem foods. For 5 apps, the behavioral theory underpinning their development was clearly specified. Frequently applied behavior change techniques are prompting self-monitoring of behavior and providing feedback on performance. Apps can function self-contained, but most of them are used as part of therapy or to strengthen school programs. From the age of 10 years users may be capable of using apps. Only 4 apps were developed specifically for adolescents. All apps were tested on a small scale and for a short period. Despite large potential and abundant usage by young people, limited research is available on apps and health promotion for adolescents. Apps seem to be a
Theoretical thermal dosimetry produced by an annular phased array system in CT-based patient models
International Nuclear Information System (INIS)
Paulsen, K.D.; Strohbehn, J.W.; Lynch, D.R.
1984-01-01
Theoretical calculations for the specific absorption rate (SAR) and the resulting temperature distributions produced by an annular phased array (APA) type system are made. The finite element numerical method is used in the formulation of both the electromagnetic (EM) and the thermal boundary value problems. A number of detailed patient models based on CT-scan data from the pelvic, visceral, and thoracic regions are generated to stimulate a variety of tumor locations and surrounding normal tissues. The SAR values from the EM solution are input into the bioheat transfer equation, and steady-rate temperature distributions are calculated for a wide variety of blood flow rates. Based on theoretical modeling, the APA shows no preferential heating of superficial over deep-seated tumors. However, in most cases satisfactory thermal profiles (therapeutic volume near 60%) are obtained in all three regions of the human trunk only for tumors with little or no blood flow. Unsatisfactory temperature patterns (therapeutic volume <50%) are found for tumors with moderate to high perfusion rates. These theoretical calculations should aid the clinician in the evaluation of the effectiveness of APA type devices in heating tumors located in the trunk region
Effective Permittivity of Biological Tissue: Comparison of Theoretical Model and Experiment
Directory of Open Access Journals (Sweden)
Li Gun
2017-01-01
Full Text Available Permittivity of biological tissue is a critical issue for studying the biological effects of electromagnetic fields. Many theories and experiments were performed to measure or explain the permittivity characteristics in biological tissue. In this paper, we investigate the permittivity parameter in biological tissues via theoretical and experimental analysis. Firstly, we analyze the permittivity characteristic in tissue by using theories on composite material. Secondly, typical biological tissues, such as blood, fat, liver, and brain, are measured by HP4275A Multi-Frequency LCR Meter within 10 kHz to 10 MHz. Thirdly, experimental results are compared with the Bottcher-Bordewijk model, the Skipetrov equation, and the Maxwell-Gannett theory. From the theoretical perspective, blood and fat are regarded as the composition of liver and brain because of the high permittivity in blood and the opposite in fat. Volume fraction of blood in liver and brain is analyzed theoretically, and the applicability and the limitation of the models are also discussed. These results benefit further study on local biological effects of electromagnetic fields.
Directory of Open Access Journals (Sweden)
DT Wiyanti
2013-07-01
Full Text Available Salah satu metode peramalan yang paling dikembangkan saat ini adalah time series, yakni menggunakan pendekatan kuantitatif dengan data masa lampau yang dijadikan acuan untuk peramalan masa depan. Berbagai penelitian telah mengusulkan metode-metode untuk menyelesaikan time series, di antaranya statistik, jaringan syaraf, wavelet, dan sistem fuzzy. Metode-metode tersebut memiliki kekurangan dan keunggulan yang berbeda. Namun permasalahan yang ada dalam dunia nyata merupakan masalah yang kompleks. Satu metode saja mungkin tidak mampu mengatasi masalah tersebut dengan baik. Dalam artikel ini dibahas penggabungan dua buah metode yaitu Auto Regressive Integrated Moving Average (ARIMA dan Radial Basis Function (RBF. Alasan penggabungan kedua metode ini adalah karena adanya asumsi bahwa metode tunggal tidak dapat secara total mengidentifikasi semua karakteristik time series. Pada artikel ini dibahas peramalan terhadap data Indeks Harga Perdagangan Besar (IHPB dan data inflasi komoditi Indonesia; kedua data berada pada rentang tahun 2006 hingga beberapa bulan di tahun 2012. Kedua data tersebut masing-masing memiliki enam variabel. Hasil peramalan metode ARIMA-RBF dibandingkan dengan metode ARIMA dan metode RBF secara individual. Hasil analisa menunjukkan bahwa dengan metode penggabungan ARIMA dan RBF, model yang diberikan memiliki hasil yang lebih akurat dibandingkan dengan penggunaan salah satu metode saja. Hal ini terlihat dalam visual plot, MAPE, dan RMSE dari semua variabel pada dua data uji coba.Â The accuracy of time series forecasting is the subject of many decision-making processes. Time series use a quantitative approach to employ data from the past to make forecast for the future. Many researches have proposed several methods to solve time series, such as using statistics, neural networks, wavelets, and fuzzy systems. These methods have different advantages and disadvantages. But often the problem in the real world is just too complex that a
International Nuclear Information System (INIS)
Mutarelli, Rita de Cassia; Lima, Ana Cecilia de Souza; Sabundjian, Gaiane
2015-01-01
Social responsibility has been one of the great discussions in institutional management, and that is an important variable in the strategy and performance of the institutions. The Instituto de Pesquisas Energeticas e Nucleares (IPEN) has worked for the development of environmental and social issues, converging mainly to the benefit of the population. The theory that guides the social responsibility practices is always difficult to measure for several reasons. One reason for this difficulty is that social responsibility involves a variety of issues that are converted in rights, obligations and expectations of different audiences that could be internal and external to the organization. In addition, the different understanding of the institutions about social and environmental issues is another source of complexity. Based on the study context including: the topic being researched, the chosen institute and the questions resulting from the research, the aim of this paper is to propose a theoretical model to describe and analyze the social responsibility of IPEN. The main contribution of this study is to develop a model that integrates the dimensions of social responsibility. These dimensions - also called constructs - are composed of indexes and indicators that were previously used in various contexts of empirical research, combined with the theoretical and conceptual review of social responsibility. The construction of the proposed theoretical model was based on the research of various methodologies and various indicators for measuring social responsibility. This model was statistically tested, analyzed, adjusted, and the end result is a consistent model to measure the perceived value of social responsibility of IPEN. This work could also be applied to other institutions. Moreover, it may be improved and become a tool that will serve as a thermometer to measure social and environmental issues, and will support decision making in various management processes. (author)
Energy Technology Data Exchange (ETDEWEB)
Mutarelli, Rita de Cassia; Lima, Ana Cecilia de Souza; Sabundjian, Gaiane, E-mail: rmutarelli@gmail.com, E-mail: aclima@ipen.br, E-mail: gdjian@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)
2015-07-01
Social responsibility has been one of the great discussions in institutional management, and that is an important variable in the strategy and performance of the institutions. The Instituto de Pesquisas Energeticas e Nucleares (IPEN) has worked for the development of environmental and social issues, converging mainly to the benefit of the population. The theory that guides the social responsibility practices is always difficult to measure for several reasons. One reason for this difficulty is that social responsibility involves a variety of issues that are converted in rights, obligations and expectations of different audiences that could be internal and external to the organization. In addition, the different understanding of the institutions about social and environmental issues is another source of complexity. Based on the study context including: the topic being researched, the chosen institute and the questions resulting from the research, the aim of this paper is to propose a theoretical model to describe and analyze the social responsibility of IPEN. The main contribution of this study is to develop a model that integrates the dimensions of social responsibility. These dimensions - also called constructs - are composed of indexes and indicators that were previously used in various contexts of empirical research, combined with the theoretical and conceptual review of social responsibility. The construction of the proposed theoretical model was based on the research of various methodologies and various indicators for measuring social responsibility. This model was statistically tested, analyzed, adjusted, and the end result is a consistent model to measure the perceived value of social responsibility of IPEN. This work could also be applied to other institutions. Moreover, it may be improved and become a tool that will serve as a thermometer to measure social and environmental issues, and will support decision making in various management processes. (author)
Directory of Open Access Journals (Sweden)
José A. F. O. Correia
2016-01-01
Full Text Available Structural design taking into account fatigue damage requires a thorough knowledge of the behaviour of materials. In addition to the monotonic behaviour of the materials, it is also important to assess their cyclic response and fatigue crack propagation behaviour under constant and variable amplitude loading. Materials whenever subjected to fatigue cracking may exhibit mean stress effects as well as crack closure effects. In this paper, a theoretical model based on the same initial assumptions of the analytical models proposed by Hudak and Davidson and Ellyin is proposed to estimate the influence of the crack closure effects. This proposal based further on Walker’s propagation law was applied to the P355NL1 steel using an inverse analysis (back-extrapolation of experimental fatigue crack propagation results. Based on this proposed model it is possible to estimate the crack opening stress intensity factor, Kop, the relationship between U=ΔKeff/ΔK quantity and the stress intensity factor, the crack length, and the stress ratio. This allows the evaluation of the influence of the crack closure effects for different stress ratio levels, in the fatigue crack propagation rates. Finally, a good agreement is found between the proposed theoretical model and the analytical models presented in the literature.
Designing m-learning for junior registrars--activation of a theoretical model of clinical knowledge.
Kanstrup, Anne Marie; Boye, Niels; Nøhr, Christian
2007-01-01
The MINI-project aims at supporting junior registrars in the learning process of how to utilize their theoretical knowledge from Medical School in everyday clinical reasoning and practice. Due to the nature of the work--concurrent moving, learning and producing--we designed an m-learning application. This paper introduces the possibilities and challenges for design of the m-learning application based on a) analytical findings on learning and mobility as derived from the design case--an emergency medical ward b) theoretical perspectives on medical knowledge, and c) presentation of the design of an m-learning application. The design process was based on user-driven innovation and the paper discusses considerations on how to combine user-drive and generic models.
International Nuclear Information System (INIS)
Xu Jun; You Bo; Li Xin; Cui Juan
2007-01-01
To accurately measure temperatures, a novel temperature sensor based on a quartz tuning fork resonator has been designed. The principle of the quartz tuning fork temperature sensor is that the resonant frequency of the quartz resonator changes with the variation in temperature. This type of tuning fork resonator has been designed with a new doubly rotated cut work at flexural vibration mode as temperature sensor. The characteristics of the temperature sensor were evaluated and the results sufficiently met the target of development for temperature sensor. The theoretical model for temperature sensing has been developed and built. The sensor structure was analysed by finite element method (FEM) and optimized, including tuning fork geometry, tine electrode pattern and the sensor's elements size. The performance curve of output versus measured temperature is given. The results from theoretical analysis and experiments indicate that the sensor's sensitivity can reach 60 ppm 0 C -1 with the measured temperature range varying from 0 to 100 0 C
Theoretical analysis of an iron mineral-based magnetoreceptor model in birds
DEFF Research Database (Denmark)
Solov'yov, Ilia; Greiner, Walter
2007-01-01
involves two types of iron minerals (magnetite and maghemite) that were found in subcellular compartments within sensory dendrites of the upper beak of several bird species. But so far a quantitative evaluation of the proposed receptor is missing. In this article, we develop a theoretical model...... to quantitatively and qualitatively describe the magnetic field effects among particles containing iron minerals. The analysis of forces acting between these subcellular compartments shows a particular dependence on the orientation of the external magnetic field. The iron minerals in the beak are found in the form...... of crystalline maghemite platelets and assemblies of magnetite nanoparticles. We demonstrate that the pull or push to the magnetite assemblies, which are connected to the cell membrane, may reach a value of 0.2 pN-sufficient to excite specific mechanoreceptive membrane channels in the nerve cell. The theoretical...
2010-09-01
Glomerular Filtration Rate GI Gastrointestinal HA Head-Airways (region of the respiratory tract) KFEF Kidney Filtration Efficiency Factor LAF Liver...contains glomeruli, which are small tufts of blood capillaries. These capillaries have small fenestrations which allow glomerular filtration of blood...into blood or excreted. A particle diameter ɝ.5 nm is the threshold for glomerular filtration , hence the possible removal of nanoparticles through
Marchese, Anthony J.; Dryer, Fredrick L.; Choi, Mun Y.
1994-01-01
In order to develop an extensive envelope of test conditions for NASA's space-based Droplet Combustion Experiment (DCE) as well those droplet experiments which can be performed using a drop tower, the transient vaporization and combustion of methanol and n-heptane droplets were simulated using a recently developed fully time-dependent, spherically symmetric droplet combustion model. The transient vaporization of methanol and n-heptane was modeled to characterize the instantaneous gas phase composition surrounding the droplet prior to the introduction of an ignition source. The results for methanol/air showed that the entire gas phase surrounding a 2 mm methanol droplet deployed in zero-g .quickly falls outside the lean flammability limit. The gas phase surrounding an identically-sized n-heptane droplet, on the other hand, remains flammable. The combustion of methanol was then modeled considering a detailed gas phase chemical kinetic mechanism (168 steps, 26 species) and the effect of the dissolution of flame-generated water into the liquid droplet. These results were used to determine the critical ignition diameter required to achieve quasi-steady droplet combustion in a given oxidizing environment. For droplet diameters greater than the critical ignition diameter, the model predicted a finite diameter at which the flame would extinguish. These extinction diameters were found to vary significantly with initial droplet diameter. This phenomenon appears to be unique to the transient heat transfer, mass transfer and chemical kinetics of the system and thus has not been reported elsewhere to date. The extinction diameter was also shown to vary significantly with the liquid phase Lewis number since the amount of water present in the droplet at extinction is largely governed by the rate at which water is transported into the droplet via mass diffusion. Finally, the numerical results for n-heptane combustion were obtained using both 2 step and 96 step semi
Piepmeier, Jeffrey; Mohammed, Priscilla; De Amici, Giovanni; Kim, Edward; Peng, Jinzheng; Ruf, Christopher; Hanna, Maher; Yueh, Simon; Entekhabi, Dara
2016-01-01
The purpose of the Soil Moisture Active Passive (SMAP) radiometer calibration algorithm is to convert Level 0 (L0) radiometer digital counts data into calibrated estimates of brightness temperatures referenced to the Earth's surface within the main beam. The algorithm theory in most respects is similar to what has been developed and implemented for decades for other satellite radiometers; however, SMAP includes two key features heretofore absent from most satellite borne radiometers: radio frequency interference (RFI) detection and mitigation, and measurement of the third and fourth Stokes parameters using digital correlation. The purpose of this document is to describe the SMAP radiometer and forward model, explain the SMAP calibration algorithm, including approximations, errors, and biases, provide all necessary equations for implementing the calibration algorithm and detail the RFI detection and mitigation process. Section 2 provides a summary of algorithm objectives and driving requirements. Section 3 is a description of the instrument and Section 4 covers the forward models, upon which the algorithm is based. Section 5 gives the retrieval algorithm and theory. Section 6 describes the orbit simulator, which implements the forward model and is the key for deriving antenna pattern correction coefficients and testing the overall algorithm.
Evaluation of European air quality modelled by CAMx including the volatility basis set scheme
Directory of Open Access Journals (Sweden)
G. Ciarelli
2016-08-01
Full Text Available Four periods of EMEP (European Monitoring and Evaluation Programme intensive measurement campaigns (June 2006, January 2007, September–October 2008 and February–March 2009 were modelled using the regional air quality model CAMx with VBS (volatility basis set approach for the first time in Europe within the framework of the EURODELTA-III model intercomparison exercise. More detailed analysis and sensitivity tests were performed for the period of February–March 2009 and June 2006 to investigate the uncertainties in emissions as well as to improve the modelling of organic aerosol (OA. Model performance for selected gas phase species and PM2.5 was evaluated using the European air quality database AirBase. Sulfur dioxide (SO2 and ozone (O3 were found to be overestimated for all the four periods, with O3 having the largest mean bias during June 2006 and January–February 2007 periods (8.9 pbb and 12.3 ppb mean biases respectively. In contrast, nitrogen dioxide (NO2 and carbon monoxide (CO were found to be underestimated for all the four periods. CAMx reproduced both total concentrations and monthly variations of PM2.5 for all the four periods with average biases ranging from −2.1 to 1.0 µg m−3. Comparisons with AMS (aerosol mass spectrometer measurements at different sites in Europe during February–March 2009 showed that in general the model overpredicts the inorganic aerosol fraction and underpredicts the organic one, such that the good agreement for PM2.5 is partly due to compensation of errors. The effect of the choice of VBS scheme on OA was investigated as well. Two sensitivity tests with volatility distributions based on previous chamber and ambient measurements data were performed. For February–March 2009 the chamber case reduced the total OA concentrations by about 42 % on average. In contrast, a test based on ambient measurement data increased OA concentrations by about 42 % for the same period bringing
THE BASIS OF MATHEMATICAL DESCRIPTION FOR WAVE MODEL OF STRESSES PROPAGATION IN RAILWAY TRACK
Directory of Open Access Journals (Sweden)
D. M. Kurhan
2016-10-01
Full Text Available Purpose. Modern scientific research has repeatedly cited practical examples of the dynamic effects of railway track operation that go beyond the static calculation schemes. For the track sections where the train speed is approaching to the velocity of wave propagation in the slab track layers such issues are of particular relevance. An adequate tool for the study of such issues can be the use of the wave theory of stress propagation. The purpose of the article is the creation of a mathematical description of the basic principles of the stress propagation wave model in the railway track, which can be used as a basis for the practical development of the relevant calculation system. Methodology. The model of stress-strain states of the railway track on the basis of the stress wave propagation theory is to bring together the equations of the geometry of the outline of the space systems that is involved in the interaction at a given time, and the dynamic equilibrium equations of deformation. The solution is based on the use of the laws of the theory of elasticity. The wave front is described by an ellipsoid equation. When determining the variation in time of the surface position of the ellipsoid a vector approach is used. Findings. The geometry equations of the wave motion determine the volumes of material layers of the slab track involved in the interaction at a given time. The dynamic equilibrium determination of the deformed condition of the space bounded by the wave front makes it possible to calculate both the stresses and strains, and their changes during the time of the load perception. Thus, mathematical descriptions of the processes that occur in the perception of the load by the elements of railway track at high speeds were obtained. Originality. The simulation tasks of the track and rolling stock interaction, in particular taking into account the dynamic deflection of slab track were further developed. For the first time the article
Implicit constitutive models with a thermodynamic basis: a study of stress concentration
Bridges, C.; Rajagopal, K. R.
2015-02-01
Motivated by the recent generalization of the class of elastic bodies by Rajagopal (Appl Math 48:279-319, 2003), there have been several recent studies that have been carried out within the context of this new class. Rajagopal and Srinivasa (Proc R Soc Ser A 463:357-367, 2007, Proc R Soc Ser A: Math Phys Eng Sci 465:493-500, 2009) provided a thermodynamic basis for such models and appealing to the idea that rate of entropy production ought to be maximized they developed nonlinear rate equations of the form where T is the Cauchy stress and D is the stretching tensor as well as , where S is the Piola-Kirchhoff stress tensor and E is the Green-St. Venant strain tensor. We follow a similar procedure by utilizing the Gibb's potential and the left stretch tensor V from the Polar Decomposition of the deformation gradient, and we show that when the displacement gradient is small one arrives at constitutive relations of the form . This is, of course, in stark contrast to traditional elasticity wherein one obtains a single model, Hooke's law, when the displacement gradient is small. By solving a classical boundary value problem, with a particular form for f( T), we show that when the stresses are small, the strains are also small which is in agreement with traditional elasticity. However, within the context of our model, when the stress blows up the strains remain small, unlike the implications of Hooke's law. We use this model to study boundary value problems in annular domains to illustrate its efficacy.
Theoretical Framework and Model Design for Beautiful Countryside Construction in China
Directory of Open Access Journals (Sweden)
ZHENG Xiang-qun
2015-04-01
Full Text Available In the context of China today, the process of beautiful countryside construction mainly imitates the patterns of‘urbanization’construction. However, this approach leads to the loss of countryside characteristics and the separation of agricultural culture. Therefore, it's urgent to carry out research of the theoretical framework and model design for beautiful countryside construction. In this paper, based on the analysis of the beautiful countryside construction connotation, the basic theory of beautiful countryside construction was summarized in three aspects: rural complex ecosystem model, multi-functionality of rural model and sustainable development evaluation model. The basic idea of the beautiful countryside construction mode was studied. The design method of beautiful countryside construction mode was proposed in three levels: planning, scheming and evaluating. The research results might offer scientific reference for improving the scientific and operational nature of beautiful countryside construction.
Ideal flow theory for the double – shearing model as a basis for metal forming design
Alexandrov, S.; Trung, N. T.
2018-02-01
In the case of Tresca’ solids (i.e. solids obeying the Tresca yield criterion and its associated flow rule) ideal flows have been defined elsewhere as solenoidal smooth deformations in which an eigenvector field associated everywhere with the greatest principal stress (and strain rate) is fixed in the material. Under such conditions all material elements undergo paths of minimum plastic work, a condition which is often advantageous for metal forming processes. Therefore, the ideal flow theory is used as the basis of a procedure for the preliminary design of such processes. The present paper extends the theory of stationary planar ideal flow to pressure dependent materials obeying the double shearing model and the double slip and rotation model. It is shown that the original problem of plasticity reduces to a purely geometric problem. The corresponding system of equations is hyperbolic. The characteristic relations are integrated in elementary functions. In regions where one family of characteristics is straight, mapping between the principal lines and Cartesian coordinates is determined by linear ordinary differential equations. An illustrative example is provided.
Directory of Open Access Journals (Sweden)
Brukhovetskaya Natalia E.
2014-01-01
Full Text Available The article analyses factors of influence upon investment attractiveness of a public joint stock company, which are factors by the sphere of origin. The article identifies the degree and direction of influence of the factors by the sphere of origin upon investment attractiveness of a public joint stock company; factors are divided into two groups, which could be regulated directly by society and which cannot be regulated. It justifies the necessity of modelling investment attractiveness of a public joint stock company under influence of the factors with the aim of managerial decision making of two groups of stakeholders: owners and managers, shareholders and investors. It conducts modelling of investment attractiveness of a public joint stock company using the decision tree method. It develops a decision matrix, on the basis of which the owners, managers, shareholders and investors can make decisions regarding directions of increase of investment attractiveness of a public joint stock company and expediency of initial or further investing into society development.
International Nuclear Information System (INIS)
Scialdone, Onofrio; Guarisco, Chiara; Galia, Alessandro
2011-01-01
The electrochemical oxidation of organics in water performed in micro reactors on boron doped diamond (BDD) anode was investigated both theoretically and experimentally in order to find the influence of various operative parameters on the conversion and the current efficiency CE of the process. The electrochemical oxidation of formic acid (FA) was selected as a model case. High conversions for a single passage of the electrolytic solution inside the cell were obtained by operating with proper residence times and low distances between cathode and anode. The effect of initial concentration, flow rate and current density was investigated in detail. Theoretical predictions were in very good agreement with experimental results for both mass transfer control, oxidation reaction control and mixed kinetic regimes in spite of the fact that no adjustable parameters was used. Mass transfer process was successfully modelled by considering for simplicity a constant Sh number (e.g., a constant mass transfer coefficient k m ) for a process performed with no high values of the current intensity to minimize the effect of the gas bubbling on the flowdynamic pattern. For mixed kinetic regimes, two different modelling approaches were used. In the first one, the oxidation of organics at BDD was assumed to be mass transfer controlled and to occur with an intrinsic 100% CE when applied current density is higher than the limiting current density. In the second case, the CE of the process was modelled assuming that the competition between organic and water oxidation depends only on the electrodic material and on the nature and the concentration of the organic. In the latter case a better agreement between experimental data and theoretical predictions was observed.
Kovalnogov, Vladislav N.; Fedorov, Ruslan V.; Khakhaleva, Larisa V.; Chukalin, Andrey V.; Bondarenko, Aleksandr A.; Kovrizhnykh, Evgeny N.
2017-07-01
Generalization of classical model of a displacement way on the transfer of heat exchange and mass exchange of a stream in the boundary layer, confirmed by the control action of the different nature, is undertaken. Here are given the results of numerical research which have allowed explaining the mechanism, to reveal efficiency and limits of various ways of management of intensity in exchange processes. The possibility of management of intensity in processes of a thermolysis and friction by use of the perforated surface with the damping cavities is analyzed.
Schuwirth, Nele; Reichert, Peter
2013-02-01
For the first time, we combine concepts of theoretical food web modeling, the metabolic theory of ecology, and ecological stoichiometry with the use of functional trait databases to predict the coexistence of invertebrate taxa in streams. We developed a mechanistic model that describes growth, death, and respiration of different taxa dependent on various environmental influence factors to estimate survival or extinction. Parameter and input uncertainty is propagated to model results. Such a model is needed to test our current quantitative understanding of ecosystem structure and function and to predict effects of anthropogenic impacts and restoration efforts. The model was tested using macroinvertebrate monitoring data from a catchment of the Swiss Plateau. Even without fitting model parameters, the model is able to represent key patterns of the coexistence structure of invertebrates at sites varying in external conditions (litter input, shading, water quality). This confirms the suitability of the model concept. More comprehensive testing and resulting model adaptations will further increase the predictive accuracy of the model.
Lin, L.; Luo, X.; Qin, F.; Yang, J.
2018-03-01
As one of the combustion products of hydrocarbon fuels in a combustion-heated wind tunnel, water vapor may condense during the rapid expansion process, which will lead to a complex two-phase flow inside the wind tunnel and even change the design flow conditions at the nozzle exit. The coupling of the phase transition and the compressible flow makes the estimation of the condensation effects in such wind tunnels very difficult and time-consuming. In this work, a reduced theoretical model is developed to approximately compute the nozzle-exit conditions of a flow including real-gas and homogeneous condensation effects. Specifically, the conservation equations of the axisymmetric flow are first approximated in the quasi-one-dimensional way. Then, the complex process is split into two steps, i.e., a real-gas nozzle flow but excluding condensation, resulting in supersaturated nozzle-exit conditions, and a discontinuous jump at the end of the nozzle from the supersaturated state to a saturated state. Compared with two-dimensional numerical simulations implemented with a detailed condensation model, the reduced model predicts the flow parameters with good accuracy except for some deviations caused by the two-dimensional effect. Therefore, this reduced theoretical model can provide a fast, simple but also accurate estimation of the condensation effect in combustion-heated hypersonic tunnels.
Directory of Open Access Journals (Sweden)
Kimberly S. Young
2017-10-01
Full Text Available Although, it is not yet officially recognized as a clinical entity which is diagnosable, Internet Gaming Disorder (IGD has been included in section III for further study in the DSM-5 by the American Psychiatric Association (APA, 2013. This is important because there is increasing evidence that people of all ages, in particular teens and young adults, are facing very real and sometimes very severe consequences in daily life resulting from an addictive use of online games. This article summarizes general aspects of IGD including diagnostic criteria and arguments for the classification as an addictive disorder including evidence from neurobiological studies. Based on previous theoretical considerations and empirical findings, this paper examines the use of one recently proposed model, the Interaction of Person-Affect-Cognition-Execution (I-PACE model, for inspiring future research and for developing new treatment protocols for IGD. The I-PACE model is a theoretical framework that explains symptoms of Internet addiction by looking at interactions between predisposing factors, moderators, and mediators in combination with reduced executive functioning and diminished decision making. Finally, the paper discusses how current treatment protocols focusing on Cognitive-Behavioral Therapy for Internet addiction (CBT-IA fit with the processes hypothesized in the I-PACE model.
Theoretical Hill-type muscle and stability: numerical model and application.
Schmitt, S; Günther, M; Rupp, T; Bayer, A; Häufle, D
2013-01-01
The construction of artificial muscles is one of the most challenging developments in today's biomedical science. The application of artificial muscles is focused both on the construction of orthotics and prosthetics for rehabilitation and prevention purposes and on building humanoid walking machines for robotics research. Research in biomechanics tries to explain the functioning and design of real biological muscles and therefore lays the fundament for the development of functional artificial muscles. Recently, the hyperbolic Hill-type force-velocity relation was derived from simple mechanical components. In this contribution, this theoretical yet biomechanical model is transferred to a numerical model and applied for presenting a proof-of-concept of a functional artificial muscle. Additionally, this validated theoretical model is used to determine force-velocity relations of different animal species that are based on the literature data from biological experiments. Moreover, it is shown that an antagonistic muscle actuator can help in stabilising a single inverted pendulum model in favour of a control approach using a linear torque generator.
Theoretical Hill-Type Muscle and Stability: Numerical Model and Application
Schmitt, S.; Günther, M.; Rupp, T.; Bayer, A.; Häufle, D.
2013-01-01
The construction of artificial muscles is one of the most challenging developments in today's biomedical science. The application of artificial muscles is focused both on the construction of orthotics and prosthetics for rehabilitation and prevention purposes and on building humanoid walking machines for robotics research. Research in biomechanics tries to explain the functioning and design of real biological muscles and therefore lays the fundament for the development of functional artificial muscles. Recently, the hyperbolic Hill-type force-velocity relation was derived from simple mechanical components. In this contribution, this theoretical yet biomechanical model is transferred to a numerical model and applied for presenting a proof-of-concept of a functional artificial muscle. Additionally, this validated theoretical model is used to determine force-velocity relations of different animal species that are based on the literature data from biological experiments. Moreover, it is shown that an antagonistic muscle actuator can help in stabilising a single inverted pendulum model in favour of a control approach using a linear torque generator. PMID:24319495
Young, Kimberly S.; Brand, Matthias
2017-01-01
Although, it is not yet officially recognized as a clinical entity which is diagnosable, Internet Gaming Disorder (IGD) has been included in section III for further study in the DSM-5 by the American Psychiatric Association (APA, 2013). This is important because there is increasing evidence that people of all ages, in particular teens and young adults, are facing very real and sometimes very severe consequences in daily life resulting from an addictive use of online games. This article summarizes general aspects of IGD including diagnostic criteria and arguments for the classification as an addictive disorder including evidence from neurobiological studies. Based on previous theoretical considerations and empirical findings, this paper examines the use of one recently proposed model, the Interaction of Person-Affect-Cognition-Execution (I-PACE) model, for inspiring future research and for developing new treatment protocols for IGD. The I-PACE model is a theoretical framework that explains symptoms of Internet addiction by looking at interactions between predisposing factors, moderators, and mediators in combination with reduced executive functioning and diminished decision making. Finally, the paper discusses how current treatment protocols focusing on Cognitive-Behavioral Therapy for Internet addiction (CBT-IA) fit with the processes hypothesized in the I-PACE model. PMID:29104555
Theoretical Hill-Type Muscle and Stability: Numerical Model and Application
Directory of Open Access Journals (Sweden)
S. Schmitt
2013-01-01
Full Text Available The construction of artificial muscles is one of the most challenging developments in today’s biomedical science. The application of artificial muscles is focused both on the construction of orthotics and prosthetics for rehabilitation and prevention purposes and on building humanoid walking machines for robotics research. Research in biomechanics tries to explain the functioning and design of real biological muscles and therefore lays the fundament for the development of functional artificial muscles. Recently, the hyperbolic Hill-type force-velocity relation was derived from simple mechanical components. In this contribution, this theoretical yet biomechanical model is transferred to a numerical model and applied for presenting a proof-of-concept of a functional artificial muscle. Additionally, this validated theoretical model is used to determine force-velocity relations of different animal species that are based on the literature data from biological experiments. Moreover, it is shown that an antagonistic muscle actuator can help in stabilising a single inverted pendulum model in favour of a control approach using a linear torque generator.
A P-value model for theoretical power analysis and its applications in multiple testing procedures
Directory of Open Access Journals (Sweden)
Fengqing Zhang
2016-10-01
Full Text Available Abstract Background Power analysis is a critical aspect of the design of experiments to detect an effect of a given size. When multiple hypotheses are tested simultaneously, multiplicity adjustments to p-values should be taken into account in power analysis. There are a limited number of studies on power analysis in multiple testing procedures. For some methods, the theoretical analysis is difficult and extensive numerical simulations are often needed, while other methods oversimplify the information under the alternative hypothesis. To this end, this paper aims to develop a new statistical model for power analysis in multiple testing procedures. Methods We propose a step-function-based p-value model under the alternative hypothesis, which is simple enough to perform power analysis without simulations, but not too simple to lose the information from the alternative hypothesis. The first step is to transform distributions of different test statistics (e.g., t, chi-square or F to distributions of corresponding p-values. We then use a step function to approximate each of the p-value’s distributions by matching the mean and variance. Lastly, the step-function-based p-value model can be used for theoretical power analysis. Results The proposed model is applied to problems in multiple testing procedures. We first show how the most powerful critical constants can be chosen using the step-function-based p-value model. Our model is then applied to the field of multiple testing procedures to explain the assumption of monotonicity of the critical constants. Lastly, we apply our model to a behavioral weight loss and maintenance study to select the optimal critical constants. Conclusions The proposed model is easy to implement and preserves the information from the alternative hypothesis.
Stateczny, A.; Lubczonek, J.
2003-04-01
The basic problem in the construction of a numerical spatial sea chart is such transformation of the sounding data that it should be possible to determine the depth at any point of the bottom area. In recent years, much attention has been devoted to the problem of modelling the seabed shape in a numerical three-dimensional sea chart. Various methods for modelling the seabed shape are applied. These methods can be divided into analytical and neural. In the case of applying the model for navigational tasks, the selection of a suitable method should ensure high accuracy of surface projection. The model should be conformed to the surface shape, spatial distribution of the measurement points and their number. The application of universal methods like 'multiquadric' or 'kriging' does not ensure an optimal result either, as each of these methods can have a certain number of options and parameters, which frequently play a significant role during surface modelling. It is often difficult to optimise these factors and even experience does not guarantee a satisfactory result. This applies especially to modelling irregular surfaces, when it is difficult to select the method suitable for the surface shape that is sometimes unpredictable. It has been suggested that the method of selecting the shape parameter of the radial basis functions should be applied which makes it possible to minimise the mean square error of the approximated surface. The paper presents a new method of optimising the parameters of radial functions used for modelling the bottom surface. The accuracy of the surface projection obtained was the criterion for optimisation. The properties of self-organizing networks created the possibility of selecting testing points out of any set of measurement points and the determination of the minimum value of RMS error by means of the GRNN network. Optimisation of the shape parameter required building the proper polygon of the test points. For building such kind of polygon
Energy Technology Data Exchange (ETDEWEB)
Staub, Isabelle; Fredriksson, Anders; Outters, Nils [Golder Associates AB, Uppsala (Sweden)
2002-05-01
In the purpose of studying the possibilities of a Deep Repository for spent fuel, the Swedish Nuclear and Fuel Management Company (SKB) is currently planning for Site Investigations. Data collected from these Site Investigations are interpreted and analysed to achieve the full Site Description, which is built up of models from all the disciplines that are considered of importance for the Site Description. One of these models is the Rock Mechanical Descriptive Model,which would be developed for any site in hard crystalline rock, and is a combination and evaluation of the characterisation of rock mass by means of empirical relationships and a theoretical approach based on numerical modelling. The present report describes the theoretical approach. The characterisation of the mechanical properties of the rock mass, viewed as a unit consisting of intact rock and fractures, is achieved by numerical simulations with following input parameters: initial stresses, fracture geometry, distribution of rock mechanical properties, such as deformation and strength parameters, for the intact rock and for the fractures. The numerical modelling was performed with the two-dimensional code UDEC, and the rock block models were generated from 2D trace sections extracted from the 3D Discrete Fracture Network (DFN) model. Assumptions and uncertainties related to the set-up of the model are considered. The numerical model was set-up to simulate a plain strain-loading test. Different boundary conditions were applied on the model for simulating stress conditions (I) in the undisturbed rock mass, and (II) at the proximity of a tunnel. In order to assess the reliability of the model sensitivity analyses have been conducted on some rock block models for defining the dependency of mechanical properties to in situ stresses, the influence of boundary conditions, rock material and joint constitutive models used to simulate the behaviour of intact rock and fractures, domain size and anisotropy. To
Directory of Open Access Journals (Sweden)
Andrej Pogorelec
2004-01-01
Full Text Available Library users searching through non-fiction library material by subject in online OPACs, expect to be able to search fiction by subject as well. The research project Skriti zaklad (Hidden Treasure was launched in 2002 and was aimed at improving the current subject description of non-juvenile literary works in Slovenian libraries. An overview of the current practice of fiction subject description in Slovenian libraries revealed that Universal Decimal Classification class numbers are usually assigned, while subject headings or abstracts are scarce. The article presents a model designed for subject description of fiction, with special emphasis on subject headings, for the Bežigrad High School Library and the Bežigrad Public Library (both in Ljubljana.
Datta Sharma, Ravi; Goswami, Nabajyoti; Ghosh, Debasree; Majumder, Sudip
2017-08-01
β-trefoil is one of the superfolds among proteins. Important classes of proteins like Interleukins (ILs), FibroblastGrowth Factors (FGFs), Kunitz (STI) family of inhibitors etc. belong to this fold. Kunitz (STI) family of inhibitors of proteins possess a highly conserved and structurally important Trytophan 91 (W91) residue, which stitches the top layer of the barrel with the lid. In this article we have investigated the molecular insights of the involvement of this W91 residue in the stability and folding pathway of Kunitz (STI) family. Winged bean Chymotrypsin inhibitor (WCI), a member of Kunitz (STI) family was chosen as a model system for carrying out the work. Molecular dynamics (MD) simulations were run with a set of total six proteins, including wild type WCI (WT) & five mutants namely W91F, W91M, W91A, W91H and W91I. Among all of them the coordinates of four proteins were taken from their crystal structures deposited in the Protein Data Bank (PDB), where as the coordinates for the rest two was generated using in-silico modelling. Our results suggest that truly this W91 residue plays a determining role in stability and folding pathway of Kunitz (STI) family. The mutants are less stable and more susceptible to quicker unfolding at higher temperatures compared to the wild type WCI. These effects are most pronounced for the smallest mutants namely W91H and W91A, indicating more is the cavity created by mutation at W91 position more the proteins becomes unstable. Copyright © 2017 Elsevier Inc. All rights reserved.
Szundi, I; Stoeckenius, W
1989-08-01
We have developed a surface model of purple membrane and applied it in an analysis of the purple-to-blue color change of bacteriorhodopsin which is induced by acidification or deionization. The model is based on dissociation and double layer theory and the known membrane structure. We calculated surface pH, ion concentrations, charge density, and potential as a function of bulk pH and concentration of mono- and divalent cations. At low salt concentrations, the surface pH is significantly lower than the bulk pH and it becomes independent of bulk pH in the deionized membrane suspension. Using an experimental acid titration curve for neutral, lipid-depleted membrane, we converted surface pH into absorption values. The calculated bacteriohodopsin color changes for acidification of purple, and titrations of deionized blue membrane with cations or base agree well with experimental results. No chemical binding is required to reproduce the experimental curves. Surface charge and potential changes in acid, base and cation titrations are calculated and their relation to the color change is discussed. Consistent with structural data, 10 primary phosphate and two basic surface groups per bacteriorhodopsin are sufficient to obtain good agreement between all calculated and experimental curves. The results provide a theoretical basis for our earlier conclusion that the purple-to-blue transition must be attributed to surface phenomena and not to cation binding at specific sites in the protein.
Directory of Open Access Journals (Sweden)
Vladimir Dmitrievich Bogdanov
2016-03-01
Full Text Available The most common international standards for the non-financial reporting are reviewed. The Global Reporting Initiative (GRI is determined as an optimal standard of sustainability reporting for the use in the Russian conditions. The environmental component of guidance on the compilation of G4 non-financial reporting of GRI standard is analyzed, the contribution of each aspect in terms of the overall picture of sustainability is determined. The progress of economic science has outlined the importance of incorporating natural components. Moreover, the value of biological resources would be increased through time, and therefore, the economic development of the company cannot be in isolation. To determine the degree of harmony between the economic development and ecological condition of the territory where the company carries out the economic activities, the application of new approaches and methods is necessary. Based on the statistical methods, a correlation model between economic development and environmental performance is developed to identify their relationship on the basis of non-financial reporting. The developed model of correlation can be used by a wide range of oil and gas companies and its general principles by the companies of different industries. The results may be of interest to stakeholders, also, it can be used for administrative purposes, to serve as a platform for forecasting and adoption of administrative decisions to achieve harmony between economic development and environmental performance. The model of correlation has been tested for the data of non-financial reporting of the Russian largest oil and gas company JSC “Surgutneftegas”. The testing has shown a positive relationship between the two systems of the company’s sustainable development: economy and ecology. This obtained result demonstrates a high level of social responsibility of the company in terms of environmental protection. A further study in this field can
Modeling Radiation Effects of Ultrasoft X Rays on the Basis of Amorphous Track Structure.
Buch, Tamara; Scifoni, Emanuele; Krämer, Michael; Durante, Marco; Scholz, Michael; Friedrich, Thomas
2018-01-01
There is experimental evidence that ultrasoft X rays (0.1-5 keV) show a higher biological effectiveness than high-energy photons. Similar to high-LET radiation, this is attributed to a rather localized dose distribution associated with a considerably smaller range of secondary electrons, which results in an increasing yield of double-strand breaks (DSBs) and potentially more complex lesions. We previously reported on the application of the Giant LOop Binary LEsion (GLOBLE) model to ultrasoft X rays, in which experimental values of the relative biological effectiveness (RBE) for DSB induction were used to show that this increasing DSB yield was sufficient to explain the enhanced effectiveness in the cell inactivation potential of ultrasoft X rays. Complementary to GLOBLE, we report here on a modeling approach to predict the increased DSB yield of ultrasoft X rays on the basis of amorphous track structure formed by secondary electrons, which was derived from Monte Carlo track structure simulations. This procedure is associated with increased production of single-strand break (SSB) clusters, which are caused by the highly localized energy deposition pattern induced by low-energy photons. From this, the RBE of ultrasoft X rays can be determined and compared to experimental data, showing that the inhomogeneity of the energy deposition pattern represents the key variable to describe the increased biological effectiveness of ultrasoft X rays. Thus, this work demonstrates an extended applicability of the amorphous track structure concept and tests its limits with respect to its predictive power. The employed model mechanism offers a possible explanation for how the cellular response to ultrasoft X rays is directly linked to the energy deposition properties on the nanometric scale.
Directory of Open Access Journals (Sweden)
Kristien Michielsen
2012-01-01
Full Text Available This paper assesses the extent to which HIV prevention interventions for young people in sub-Saharan Africa are grounded in theory and if theory-based interventions are more effective. Three databases were searched for evaluation studies of HIV prevention interventions for youth. Additional articles were identified on websites of international organisations and through searching references. 34 interventions were included; 25 mentioned the use of theory. Social Cognitive Theory was most prominent (n=13, followed by Health Belief Model (n=7, and Theory of Reasoned Action/Planned Behaviour (n=6. These cognitive behavioural theories assume that cognitions drive sexual behaviour. Reporting on choice and use of theory was low. Only three articles provided information about why a particular theory was selected. Interventions used theory to inform content (n=13, for evaluation purposes (n=4 or both (n=7. No patterns of differential effectiveness could be detected between studies using and not using theory, or according to whether a theory informed content, and/or evaluation. We discuss characteristics of the theories that might account for the limited effectiveness observed, including overreliance on cognitions that likely vary according to type of sexual behaviour and other personal factors, inadequately address interpersonal factors, and failure to account for contextual factors.
Michielsen, Kristien; Chersich, Matthew; Temmerman, Marleen; Dooms, Tessa; Van Rossem, Ronan
2012-01-01
This paper assesses the extent to which HIV prevention interventions for young people in sub-Saharan Africa are grounded in theory and if theory-based interventions are more effective. Three databases were searched for evaluation studies of HIV prevention interventions for youth. Additional articles were identified on websites of international organisations and through searching references. 34 interventions were included; 25 mentioned the use of theory. Social Cognitive Theory was most prominent (n = 13), followed by Health Belief Model (n = 7), and Theory of Reasoned Action/Planned Behaviour (n = 6). These cognitive behavioural theories assume that cognitions drive sexual behaviour. Reporting on choice and use of theory was low. Only three articles provided information about why a particular theory was selected. Interventions used theory to inform content (n = 13), for evaluation purposes (n = 4) or both (n = 7). No patterns of differential effectiveness could be detected between studies using and not using theory, or according to whether a theory informed content, and/or evaluation. We discuss characteristics of the theories that might account for the limited effectiveness observed, including overreliance on cognitions that likely vary according to type of sexual behaviour and other personal factors, inadequately address interpersonal factors, and failure to account for contextual factors.
A simplified theoretical model for the laser-induced optogalvanic effect
International Nuclear Information System (INIS)
Mirage, A.
1990-01-01
A simplified theoretical model for an estimate of the optogalvanic effect induced in an electric discharge by resonant laser radiation is presented. This theory is based on the solution of a two-level system rate equation, where the upper level of the stimulated transition is connected to the ground state (lower level) through radiative and collisional processes. The developed relations show that the magnitude and temporal evolution (in the case of pulsed excitation) of the optogalvanic signal depend on the electronic plasma density, electron temperature and on the density of light absorbing centers. (author) [pt
Ding, Ya
2018-01-01
In recent years, many areas of China have been facing increasing problems of soil erosion and land degradation. Conservation tillage, with both economic and ecological benefits, provides a good avenue for Chinese farmers to conserve land as well as secure food production. However, the adoption rate of conservation tillage systems is very low in China. In this paper, the author constructs a theoretical model to explain a farmer’s adoption decision of conservation tillage. The goal is to investigate potential reasons behind the low adoption rate and explores alternative policy tools that can help improve a farmer’s incentive to adopt conservation tillage in China.
Use of Graph-Theoretic Models in Technological Preparation of Assembly Plant
Directory of Open Access Journals (Sweden)
Peter Franzevich Yurchik
2015-05-01
Full Text Available The article examines the existing ways of describing the structural and technological properties of the product in the process of building and repair. It turned out that the main body of work on the preparation process of assembling production uses graph-theoretic model of the product. It is shown that, in general, the structural integrity of many-form connections and relations on the set of components that can not be adequately described by binary structures, such as graphs, networks or trees.
The lack of theoretical support for using person trade-offs in QALY-type models
DEFF Research Database (Denmark)
Østerdal, Lars Peter Raahave
2009-01-01
Considerable support for the use of person trade-off methods to assess the quality-adjustment factor in quality-adjusted life years (QALY) models has been expressed in the literature. The WHO has occasionally used similar methods to assess the disability weights for calculation of disability......-adjusted life years (DALYs). This paper discusses the theoretical support for the use of person trade-offs in QALY-type measurement of (changes in) population health. It argues that measures of this type based on such quality-adjustment factors almost always violate the Pareto principle, and so lack normative...
The neural mediators of kindness-based meditation: a theoretical model
Directory of Open Access Journals (Sweden)
Jennifer Streiffer Mascaro
2015-02-01
Full Text Available Although kindness-based contemplative practices are increasingly employed by clinicians and cognitive researchers to enhance prosocial emotions, social cognitive skills, and well-being, and as a tool to understand the basic workings of the social mind, we lack a coherent theoretical model with which to test the mechanisms by which kindness-based meditation may alter the brain and body. Here we link contemplative accounts of compassion and loving-kindness practices with research from social cognitive neuroscience and social psychology to generate predictions about how diverse practices may alter brain structure and function and related aspects of social cognition. Contingent on the nuances of the practice, kindness-based meditation may enhance the neural systems related to faster and more basic perceptual or motor simulation processes, simulation of another’s affective body state, slower and higher-level perspective-taking, modulatory processes such as emotion regulation and self/other discrimination, and combinations thereof. This theoretical model will be discussed alongside best practices for testing such a model and potential implications and applications of future work.
Hyer, E. J.; Reid, J. S.; Schmidt, C. C.; Giglio, L.; Prins, E.
2009-12-01
The diurnal cycle of fire activity is crucial for accurate simulation of atmospheric effects of fire emissions, especially at finer spatial and temporal scales. Estimating diurnal variability in emissions is also a critical problem for construction of emissions estimates from multiple sensors with variable coverage patterns. An optimal diurnal emissions estimate will use as much information as possible from satellite fire observations, compensate known biases in those observations, and use detailed theoretical models of the diurnal cycle to fill in missing information. As part of ongoing improvements to the Fire Location and Monitoring of Burning Emissions (FLAMBE) fire monitoring system, we evaluated several different methods of integrating observations with different temporal sampling. We used geostationary fire detections from WF_ABBA, fire detection data from MODIS, empirical diurnal cycles from TRMM, and simple theoretical diurnal curves based on surface heating. Our experiments integrated these data in different combinations to estimate the diurnal cycles of emissions for each location and time. Hourly emissions estimates derived using these methods were tested using an aerosol transport model. We present results of this comparison, and discuss the implications of our results for the broader problem of multi-sensor data fusion in fire emissions modeling.
Theoretical and experimental stress analyses of ORNL thin-shell cylinder-to-cylinder model 2
International Nuclear Information System (INIS)
Gwaltney, R.C.; Bolt, S.E.; Bryson, J.W.
1975-10-01
Model 2 in a series of four thin-shell cylinder-to-cylinder models was tested, and the experimentally determined elastic stress distributions were compared with theoretical predictions obtained from a thin-shell finite-element analysis. Both the cylinder and the nozzle of model 2 had outside diameters of 10 in., giving a d 0 /D 0 ratio of 1.0, and both had outside diameter/thickness ratios of 100. Sixteen separate loading cases in which one end of the cylinder was rigidly held were analyzed. An internal pressure loading, three mutually perpendicular force components, and three mutually perpendicular moment components were individually applied at the free end of the cylinder and at the end of the nozzle. In addition to these 13 loadings, 3 additional loads were applied to the nozzle (in-plane bending moment, out-of-plane bending moment, and axial force) with the free end of the cylinder restrained. The experimental stress distributions for each of the 16 loadings were obtained using 152 three-gage strain rosettes located on the inner and outer surfaces. All the 16 loading cases were also analyzed theoretically using a finite-element shell analysis. The analysis used flat-plate elements and considered five degrees of freedom per node in the final assembled equations. The comparisons between theory and experiment show reasonably good general agreement, and it is felt that the analysis would be satisfactory for most engineering purposes. (auth)
A theoretical model of speed-dependent steering torque for rolling tyres
Wei, Yintao; Oertel, Christian; Liu, Yahui; Li, Xuebing
2016-04-01
It is well known that the tyre steering torque is highly dependent on the tyre rolling speed. In limited cases, i.e. parking manoeuvre, the steering torque approaches the maximum. With the increasing tyre speed, the steering torque decreased rapidly. Accurate modelling of the speed-dependent behaviour for the tyre steering torque is a key factor to calibrate the electric power steering (EPS) system and tune the handling performance of vehicles. However, no satisfactory theoretical model can be found in the existing literature to explain this phenomenon. This paper proposes a new theoretical framework to model this important tyre behaviour, which includes three key factors: (1) tyre three-dimensional transient rolling kinematics with turn-slip; (2) dynamical force and moment generation; and (3) the mixed Lagrange-Euler method for contact deformation solving. A nonlinear finite-element code has been developed to implement the proposed approach. It can be found that the main mechanism for the speed-dependent steering torque is due to turn-slip-related kinematics. This paper provides a theory to explain the complex mechanism of the tyre steering torque generation, which helps to understand the speed-dependent tyre steering torque, tyre road feeling and EPS calibration.
The neural mediators of kindness-based meditation: a theoretical model.
Mascaro, Jennifer S; Darcher, Alana; Negi, Lobsang T; Raison, Charles L
2015-01-01
Although kindness-based contemplative practices are increasingly employed by clinicians and cognitive researchers to enhance prosocial emotions, social cognitive skills, and well-being, and as a tool to understand the basic workings of the social mind, we lack a coherent theoretical model with which to test the mechanisms by which kindness-based meditation may alter the brain and body. Here, we link contemplative accounts of compassion and loving-kindness practices with research from social cognitive neuroscience and social psychology to generate predictions about how diverse practices may alter brain structure and function and related aspects of social cognition. Contingent on the nuances of the practice, kindness-based meditation may enhance the neural systems related to faster and more basic perceptual or motor simulation processes, simulation of another's affective body state, slower and higher-level perspective-taking, modulatory processes such as emotion regulation and self/other discrimination, and combinations thereof. This theoretical model will be discussed alongside best practices for testing such a model and potential implications and applications of future work.
Directory of Open Access Journals (Sweden)
Alvaro Ruíz-Baltazar
2015-12-01
Full Text Available In this research, the adsorption capacity of Ag nanoparticles on natural zeolite from Oaxaca is presented. In order to describe the adsorption mechanism of silver nanoparticles on zeolite, experimental adsorption models for Ag ions and Ag nanoparticles were carried out. These experimental data obtained by the atomic absorption spectrophotometry technique were compared with theoretical models such as Lagergren first-order, pseudo-second-order, Elovich, and intraparticle diffusion. Correlation factors R2 of the order of 0.99 were observed. Analysis by transmission electron microscopy describes the distribution of the silver nanoparticles on the zeolite outer surface. Additionally, a chemical characterization of the material was carried out through a dilution process with lithium metaborate. An average value of 9.3 in the Si/Al ratio was observed. Factors such as the adsorption behavior of the silver ions and the Si/Al ratio of the zeolite are very important to support the theoretical models and establish the adsorption mechanism of Ag nanoparticles on natural zeolite.
A theoretical model for metal-graphene contact resistance using a DFT-NEGF method.
Ji, Xiang; Zhang, Jinyu; Wang, Yan; Qian, He; Yu, Zhiping
2013-11-07
The contact resistance (R(c)) between graphene and metal electrodes is of crucial importance for achieving potentially high performances for graphene devices. However, previous analytical models based on Landauer's approach have failed to include the Fermi velocity difference between the graphene under the metal and the pure graphene channel. Hereby we report a theoretical model to estimate the R(c) using density-functional theory and non-equilibrium Green's function methods. Our model not only presents a clear physical picture of the metal-graphene contacts, but also generates R(c) values which are in good agreement with the experimental results: 210 Ω μm for double-sided Pd contacts compared with 403 Ω μm for single-sided Pd contact.
de Andrade, Rocelito Lopes; de Oliveira, Matheus Costa; Kohlrausch, Emerson Cristofer; Santos, Marcos José Leite
2018-05-01
This work presents a new and simple method for determining IPH (current source dependent on luminance), I0 (reverse saturation current), n (ideality factor), RP and RS, (parallel and series resistance) to build an electrical model for dye sensitized solar cells (DSSCs). The electrical circuit parameters used in the simulation and to generate theoretical curves for the single diode electrical model were extracted from I-V curves of assembled DSSCs. Model validation was performed by assembling five different types of DSSCs and evaluating the following parameters: effect of a TiO2 blocking/adhesive layer, thickness of the TiO2 layer and the presence of a light scattering layer. In addition, irradiance, temperature, series and parallel resistance, ideality factor and reverse saturation current were simulated.
Theoretical models of interstellar shocks. I - Radiative transfer and UV precursors
Shull, J. M.; Mckee, C. F.
1979-01-01
Theoretical models of interstellar radiative shocks are constructed, with special attention to the transfer of ionizing radiation. These models are 'self-consistent' in the sense that the emergent ionizing radiation (the UV precursor) is coupled with the ionization state of H, He, and the metals in the preshock gas. For shock velocities of at least 110 km/s the shocks generate sufficient UV radiation for complete preionization of H and He, the latter to He(+). At lower velocities the preionization can be much smaller, with important consequences for the cooling function, the shock structure, and the emission. For models with shock velocities of 40 to 130 km/s the intensities of the strongest emission lines in the UV, optical, and infrared are tabulated, as well as postshock column densities of metal ions potentially observable by UV absorption spectroscopy. Possible applications to supernova remnants and high-velocity interstellar gas are assessed.
Activity systems modeling as a theoretical lens for social exchange studies
Directory of Open Access Journals (Sweden)
Ernest Jones
2016-01-01
Full Text Available The social exchange perspective seeks to acknowledge, understand and predict the dynamics of social interactions. Empirical research involving social exchange constructs have grown to be highly technical including confirmatory factor analysis to assess construct distinctiveness and structural equation modeling to assess construct causality. Each study seemingly strives to assess how underlying social exchange theoretic constructs interrelate. Yet despite this methodological depth and resultant explanatory and predictive power, a significant number of studies report findings that, once synthesized, suggest an underlying persistent threat of conceptual or construct validity brought about by a search for epistemological parsimony. Further, it is argued that a methodological approach that embraces inherent complexity such as activity systems modeling facilitates the search for simplified models while not ignoring contextual factors.
Dodd, Bucky J.
2013-01-01
Online course design is an emerging practice in higher education, yet few theoretical models currently exist to explain or predict how the diffusion of innovations occurs in this space. This study used a descriptive, quantitative survey research design to examine theoretical relationships between decision-making style and resistance to change…
Brian K. Via; chi L. So; Leslie H. Groom; Todd F. Shupe; michael Stine; Jan. Wikaira
2007-01-01
A theoretical model was built predicting the relationship between microfibril angle and lignin content at the Angstrom (A) level. Both theoretical and statistical examination of experimental data supports a square root transformation of lignin to predict microfibril angle. The experimental material used came from 10 longleaf pine (Pinus palustris)...
Surface-based morphometry reveals the neuroanatomical basis of the five-factor model of personality.
Riccelli, Roberta; Toschi, Nicola; Nigro, Salvatore; Terracciano, Antonio; Passamonti, Luca
2017-04-01
The five-factor model (FFM) is a widely used taxonomy of human personality; yet its neuro anatomical basis remains unclear. This is partly because past associations between gray-matter volume and FFM were driven by different surface-based morphometry (SBM) indices (i.e. cortical thickness, surface area, cortical folding or any combination of them). To overcome this limitation, we used Free-Surfer to study how variability in SBM measures was related to the FFM in n = 507 participants from the Human Connectome Project.Neuroticism was associated with thicker cortex and smaller area and folding in prefrontal-temporal regions. Extraversion was linked to thicker pre-cuneus and smaller superior temporal cortex area. Openness was linked to thinner cortex and greater area and folding in prefrontal-parietal regions. Agreeableness was correlated to thinner prefrontal cortex and smaller fusiform gyrus area. Conscientiousness was associated with thicker cortex and smaller area and folding in prefrontal regions. These findings demonstrate that anatomical variability in prefrontal cortices is linked to individual differences in the socio-cognitive dispositions described by the FFM. Cortical thickness and surface area/folding were inversely related each others as a function of different FFM traits (neuroticism, extraversion and consciousness vs openness), which may reflect brain maturational effects that predispose or protect against psychiatric disorders. © The Author (2017). Published by Oxford University Press.
Response functions of a superlattice with a basis: A model for oxide superconductors
International Nuclear Information System (INIS)
Griffin, A.
1988-01-01
The new high-T/sub c/ oxide superconductors appear to be superlattice structures with a basis composed of metallic sheets as well as metallic chains. Using a simple free-electron-gas model for the sheets and chains, we obtain the dielectric function ε(q,ω) of such a multilayer system within the random-phase approximation (RPA). We give results valid for arbitrary wave vector q appropriate to sheets and chains (as in the orthorhombic phase of Y-Ba-Cu-O) as well as for two different kinds of sheets (such as may be present in the Bi-Ca-Sr-Cu-O superconductors). The occurrence of acoustic plasmons is a general phenomenon in such superlattices, as shown by an alternative formulation based on the exact response functions for the individual sheets and chains, in which only the interchain (sheet) Coulomb interaction is treated in the RPA. These results generalize the long-wavelength expressions recently given in the literature. We also briefly discuss the analogous results for two arrays of mutually perpendicular chains, such as found in Hg chain compounds
Holding, Matthew L; Drabeck, Danielle H; Jansa, Sharon A; Gibbs, H Lisle
2016-11-01
SynopsisVenom and venom resistance are molecular phenotypes widely considered to have diversified through coevolution between predators and prey. However, while evolutionary and functional studies on venom have been extensive, little is known about the molecular basis, variation, and complexity of venom resistance. We review known mechanisms of venom resistance and relate these mechanisms to their predicted impact on coevolutionary dynamics with venomous enemies. We then describe two conceptual approaches which can be used to examine venom/resistance systems. At the intraspecific level, tests of local adaptation in venom and resistance phenotypes can identify the functional mechanisms governing the outcomes of coevolution. At deeper evolutionary timescales, the combination of phylogenetically informed analyses of protein evolution coupled with studies of protein function promise to elucidate the mode and tempo of evolutionary change on potentially coevolving genes. We highlight case studies that use each approach to extend our knowledge of these systems as well as address larger questions about coevolutionary dynamics. We argue that resistance and venom are phenotypic traits which hold exceptional promise for investigating the mechanisms, dynamics, and outcomes of coevolution at the molecular level. Furthermore, extending the understanding of single gene-for-gene interactions to the whole resistance and venom phenotypes may provide a model system for examining the molecular and evolutionary dynamics of complex multi-gene interactions. © The Author 2016. Published by Oxford University Press on behalf of the Society for Integrative and Comparative Biology. All rights reserved. For permissions please email: journals.permissions@oup.com.
Poveda, José A; Marcela Giudici, A; Lourdes Renart, M; Morales, Andrés; González-Ros, José M
2017-09-01
Research on ion channel modulation has become a hot topic because of the key roles these membrane proteins play in both prokaryotic and eukaryotic organisms. In this respect, lipid modulation adds to the overall modulatory mechanisms as a potential via to find new pharmacological targets for drug design based on interfering with lipid/channel interactions. However, our knowledge in this field is scarce and often circumscribed to the sites where lipids bind and/or its final functional consequences. To fully understand this process it is necessary to improve our knowledge on its molecular basis, from the binding sites to the signalling pathways that derive in structural and functional effects on the ion channel. In this review, we have compiled information about such mechanisms and established a classification into four different modes of action. Afterwards, we have revised in more detail the lipid modulation of Cys-loop receptors and of the potassium channel KcsA, which were chosen as model channels modulated by specific lipids. This article is part of a Special Issue entitled: Membrane Lipid Therapy: Drugs Targeting Biomembranes edited by Pablo V. Escribá. Copyright © 2017 Elsevier B.V. All rights reserved.
DEFF Research Database (Denmark)
Avery, John Scales; Rettrup, Sten; Avery, James Emil
In theoretical physics, theoretical chemistry and engineering, one often wishes to solve partial differential equations subject to a set of boundary conditions. This gives rise to eigenvalue problems of which some solutions may be very difficult to find. For example, the problem of finding...... in such problems can be much reduced by making use of symmetry-adapted basis functions. The conventional method for generating symmetry-adapted basis sets is through the application of group theory, but this can be difficult. This book describes an easier method for generating symmetry-adapted basis sets...
The Safety Culture Enactment Questionnaire (SCEQ): Theoretical model and empirical validation.
de Castro, Borja López; Gracia, Francisco J; Tomás, Inés; Peiró, José M
2017-06-01
This paper presents the Safety Culture Enactment Questionnaire (SCEQ), designed to assess the degree to which safety is an enacted value in the day-to-day running of nuclear power plants (NPPs). The SCEQ is based on a theoretical safety culture model that is manifested in three fundamental components of the functioning and operation of any organization: strategic decisions, human resources practices, and daily activities and behaviors. The extent to which the importance of safety is enacted in each of these three components provides information about the pervasiveness of the safety culture in the NPP. To validate the SCEQ and the model on which it is based, two separate studies were carried out with data collection in 2008 and 2014, respectively. In Study 1, the SCEQ was administered to the employees of two Spanish NPPs (N=533) belonging to the same company. Participants in Study 2 included 598 employees from the same NPPs, who completed the SCEQ and other questionnaires measuring different safety outcomes (safety climate, safety satisfaction, job satisfaction and risky behaviors). Study 1 comprised item formulation and examination of the factorial structure and reliability of the SCEQ. Study 2 tested internal consistency and provided evidence of factorial validity, validity based on relationships with other variables, and discriminant validity between the SCEQ and safety climate. Exploratory Factor Analysis (EFA) carried out in Study 1 revealed a three-factor solution corresponding to the three components of the theoretical model. Reliability analyses showed strong internal consistency for the three scales of the SCEQ, and each of the 21 items on the questionnaire contributed to the homogeneity of its theoretically developed scale. Confirmatory Factor Analysis (CFA) carried out in Study 2 supported the internal structure of the SCEQ; internal consistency of the scales was also supported. Furthermore, the three scales of the SCEQ showed the expected correlation
The custodially protected Randall-Sundrum model. Theoretical aspects and flavour phenomenology
International Nuclear Information System (INIS)
Blanke, Monika
2009-01-01
Models with a warped extra dimension, so-called Randall-Sundrum models, provide an appealing solution to the gauge and flavour hierarchy problems of the Standard Model. After introducing the theoretical basics of such models, we concentrate on a specific model whose symmetry structure is extended to protect the T parameter and the Zb L anti b L coupling from large corrections. We introduce the basic action and discuss in detail effects of electroweak symmetry breaking and the flavour structure of the model. Then we analyse meson-antimeson mixing and rare decays that are affected by new tree level contributions from the Kaluza-Klein modes of the gauge bosons and from the Z boson in an important manner. After deriving analytic expressions for the most important K and B physics observables, we perform a global numerical analysis of the new effects in the model in question. We confirm the recent findings that a stringent constraint on the model is placed by CP-violation in K 0 - anti K 0 mixing. However, even for Kaluza-Klein particles in the reach of the LHC an agreement with all available data can be obtained without significant fine-tuning. We find possible large effects in either CP-violating effects in the B s - anti B s system or in the rare K decays, but not simultaneously. In any case the deviations from the Standard Model predictions in the rare B decays are small and difficult to measure. The specific pattern of new flavour effects allows to distinguish this model from other New Physics frameworks, which we demonstrate explicitly for the case of models with Minimal Flavour Violation and for the Littlest Higgs model with T-parity. (orig.)
The custodially protected Randall-Sundrum model. Theoretical aspects and flavour phenomenology
Energy Technology Data Exchange (ETDEWEB)
Blanke, Monika
2009-07-24
Models with a warped extra dimension, so-called Randall-Sundrum models, provide an appealing solution to the gauge and flavour hierarchy problems of the Standard Model. After introducing the theoretical basics of such models, we concentrate on a specific model whose symmetry structure is extended to protect the T parameter and the Zb{sub L} anti b{sub L} coupling from large corrections. We introduce the basic action and discuss in detail effects of electroweak symmetry breaking and the flavour structure of the model. Then we analyse meson-antimeson mixing and rare decays that are affected by new tree level contributions from the Kaluza-Klein modes of the gauge bosons and from the Z boson in an important manner. After deriving analytic expressions for the most important K and B physics observables, we perform a global numerical analysis of the new effects in the model in question. We confirm the recent findings that a stringent constraint on the model is placed by CP-violation in K{sup 0} - anti K{sup 0} mixing. However, even for Kaluza-Klein particles in the reach of the LHC an agreement with all available data can be obtained without significant fine-tuning. We find possible large effects in either CP-violating effects in the B{sub s} - anti B{sub s} system or in the rare K decays, but not simultaneously. In any case the deviations from the Standard Model predictions in the rare B decays are small and difficult to measure. The specific pattern of new flavour effects allows to distinguish this model from other New Physics frameworks, which we demonstrate explicitly for the case of models with Minimal Flavour Violation and for the Littlest Higgs model with T-parity. (orig.)
A theoretical model for predicting the Peak Cutting Force of conical picks
Directory of Open Access Journals (Sweden)
Gao Kuidong
2014-01-01
Full Text Available In order to predict the PCF (Peak Cutting Force of conical pick in rock cutting process, a theoretical model is established based on elastic fracture mechanics theory. The vertical fracture model of rock cutting fragment is also established based on the maximum tensile criterion. The relation between vertical fracture angle and associated parameters (cutting parameter and ratio B of rock compressive strength to tensile strength is obtained by numerical analysis method and polynomial regression method, and the correctness of rock vertical fracture model is verified through experiments. Linear regression coefficient between the PCF of prediction and experiments is 0.81, and significance level less than 0.05 shows that the model for predicting the PCF is correct and reliable. A comparative analysis between the PCF obtained from this model and Evans model reveals that the result of this prediction model is more reliable and accurate. The results of this work could provide some guidance for studying the rock cutting theory of conical pick and designing the cutting mechanism.
Modeling of air-gap membrane distillation process: A theoretical and experimental study
Alsaadi, Ahmad Salem
2013-06-03
A one dimensional (1-D) air gap membrane distillation (AGMD) model for flat sheet type modules has been developed. This model is based on mathematical equations that describe the heat and mass transfer mechanisms of a single-stage AGMD process. It can simulate AGMD modules in both co-current and counter-current flow regimes. The theoretical model was validated using AGMD experimental data obtained under different operating conditions and parameters. The predicted water vapor flux was compared to the flux measured at five different feed water temperatures, two different feed water salinities, three different air gap widths and two MD membranes with different average pore sizes. This comparison showed that the model flux predictions are strongly correlated with the experimental data, with model predictions being within +10% of the experimentally determined values. The model was then used to study and analyze the parameters that have significant effect on scaling-up the AGMD process such as the effect of increasing the membrane length, and feed and coolant flow rates. The model was also used to analyze the maximum thermal efficiency of the AGMD process by tracing changes in water production rate and the heat input to the process along the membrane length. This was used to understand the gain in both process production and thermal efficiency for different membrane surface areas and the resultant increases in process capital and water unit cost. © 2013 Elsevier B.V.
Qian, Feng; Zhou, Wanlu; Kaluvan, Suresh; Zhang, Haifeng; Zuo, Lei
2018-04-01
Vibration energy harvesting has been extensively studied in recent years to explore a continuous power source for sensor networks and low-power electronics. Torsional vibration widely exists in mechanical engineering; however, it has not yet been well exploited for energy harvesting. This paper presents a theoretical model and an experimental validation of a torsional vibration energy harvesting system comprised of a shaft and a shear mode piezoelectric transducer. The piezoelectric transducer position on the surface of the shaft is parameterized by two variables that are optimized to obtain the maximum power output. The piezoelectric transducer can work in d 15 mode (pure shear mode), coupled mode of d 31 and d 33, and coupled mode of d 33, d 31 and d 15, respectively, when attached at different angles. Approximate expressions of voltage and power are derived from the theoretical model, which gave predictions in good agreement with analytical solutions. Physical interpretations on the implicit relationship between the power output and the position parameters of the piezoelectric transducer is given based on the derived approximate expression. The optimal position and angle of the piezoelectric transducer is determined, in which case, the transducer works in the coupled mode of d 15, d 31 and d 33.
Theoretical models to predict the mechanical behavior of thick composite tubes
Directory of Open Access Journals (Sweden)
Volnei Tita
2012-02-01
Full Text Available This paper shows theoretical models (analytical formulations to predict the mechanical behavior of thick composite tubes and how some parameters can influence this behavior. Thus, firstly, it was developed the analytical formulations for a pressurized tube made of composite material with a single thick ply and only one lamination angle. For this case, the stress distribution and the displacement fields are investigated as function of different lamination angles and reinforcement volume fractions. The results obtained by the theoretical model are physic consistent and coherent with the literature information. After that, the previous formulations are extended in order to predict the mechanical behavior of a thick laminated tube. Both analytical formulations are implemented as a computational tool via Matlab code. The results obtained by the computational tool are compared to the finite element analyses, and the stress distribution is considered coherent. Moreover, the engineering computational tool is used to perform failure analysis, using different types of failure criteria, which identifies the damaged ply and the mode of failure.
A THEORETICAL MODEL OF SOCIO-PSYCHOLOGICAL SUPPORT WORK PROCESSES FOR MANAGEMENT OF PRODUCTION TEAM
Directory of Open Access Journals (Sweden)
Tatyana Gennadevna Pronyushkina
2015-10-01
Full Text Available This article discusses the management of production team, in particular the developed theoretical model of socio-psychological support work processes for management of production team. The author of the research are formulated the purpose and objectives of social-psychological work on management of the production team. Developed in the study a theoretical model aimed at determining the conditions and the identification of features of effective management of the enterprise taking into account the socio-psychological characteristics of its staff. Tasks include: definition of the main characteristics of the production team and their severity, the analysis of these characteristics and identifying opportunities for their transformation, development of recommendations for management of social-psychological work on effects on the characteristics of the collective enterprise.Practical study of the activities of a number of businesses have shown the need to improve socio-psychological support of management processes production team: introducing a social and psychological planning team and develop the practice of sociological research on the state of the team, to ensure the smoothing of relations between workers and management through periodic meetings, creations of conditions for feedback, maintaining healthy competition among team members.
International Nuclear Information System (INIS)
Li, Huajiao; An, Haizhong; Fang, Wei; Jiang, Meng
2017-01-01
The logistical issues surrounding the timing and transport of flowback generated by each shale gas well to the next is a big challenge. Due to more and more flowback being stored temporarily near the shale gas well and reused in the shale gas development, both transportation cost and storage cost are the heavy burden for the developers. This research proposed a theoretical cost optimization model to get the optimal flowback distribution solution for regional multi shale gas wells in a holistic perspective. Then, we used some empirical data of Marcellus Shale to do the empirical study. In addition, we compared the optimal flowback distribution solution by considering both the transportation cost and storage cost with the flowback distribution solution which only minimized the transportation cost or only minimized the storage cost. - Highlights: • A theoretical cost optimization model to get optimal flowback distribution solution. • An empirical study using the shale gas data in Bradford County of Marcellus Shale. • Visualization of optimal flowback distribution solutions under different scenarios. • Transportation cost is a more important factor for reducing the cost. • Help the developers to cut the storage and transportation cost of reusing flowback.
Photoluminescence of crystalline and disordered BTO:Mn powder: Experimental and theoretical modeling
International Nuclear Information System (INIS)
Gurgel, M.F.C.; Espinosa, J.W.M.; Campos, A.B.; Rosa, I.L.V.; Joya, M.R.; Souza, A.G.; Zaghete, M.A.; Pizani, P.S.; Leite, E.R.; Varela, J.A.; Longo, E.
2007-01-01
Disordered and crystalline Mn-doped BaTiO 3 (BTO:Mn) powders were synthesized by the polymeric precursor method. After heat treatment, the nature of visible photoluminescence (PL) at room temperature in amorphous BTO:Mn was discussed, considering results of experimental and theoretical studies. X-ray diffraction (XRD), PL, and UV-vis were used to characterize this material. Rietveld refinement of the BTO:Mn from XRD data was used to built two models, which represent the crystalline BTO:Mn (BTO:Mn c ) and disordered BTO:Mn (BTO:Mn d ) structures. Theses models were analyzed by the periodic ab initio quantum mechanical calculations using the CRYSTAL98 package within the framework of density functional theory at the B3LYP level. The experimental and theoretical results indicated that PL is related with the degree of disorder in the BTO:Mn powders and also suggests the presence of localized states in the disordered structure
Theoretical study on the inverse modeling of deep body temperature measurement
International Nuclear Information System (INIS)
Huang, Ming; Chen, Wenxi
2012-01-01
We evaluated the theoretical aspects of monitoring the deep body temperature distribution with the inverse modeling method. A two-dimensional model was built based on anatomical structure to simulate the human abdomen. By integrating biophysical and physiological information, the deep body temperature distribution was estimated from cutaneous surface temperature measurements using an inverse quasilinear method. Simulations were conducted with and without the heat effect of blood perfusion in the muscle and skin layers. The results of the simulations showed consistently that the noise characteristics and arrangement of the temperature sensors were the major factors affecting the accuracy of the inverse solution. With temperature sensors of 0.05 °C systematic error and an optimized 16-sensor arrangement, the inverse method could estimate the deep body temperature distribution with an average absolute error of less than 0.20 °C. The results of this theoretical study suggest that it is possible to reconstruct the deep body temperature distribution with the inverse method and that this approach merits further investigation. (paper)
Directory of Open Access Journals (Sweden)
Oya TAMTEKİN AYDIN
2017-08-01
Full Text Available Increased demand for higher education and the change and competition it has brought have been a subject for many studies. In Porter’s five forces model, forces termed as the threat of new entrants, threat of substitute products, bargaining power of suppliers, bargaining power of customers, and established rivals between the companies are used to understand the threats and opportunities posed by the industry’s environmental circumstances. The five forces model has been extensively used as an analytical tool to determine the intensity of rivalry and levels of profitability. Thus, managers can develop strategies and discover ways to defend their companies against competitive forces. Although there have been numerous studies conducted with this model for various sectors, the studies implementing this theory to higher education are very scarce due to uncertainty about whether higher education could be regarded as an industry together with its profitability and rivalry components. Specifically, in Turkey, with the idea of considering higher education to be an industry being disputable compared with western countries and even regarded as unmannerly and disloyal to academia explains the lack of studies on this subject. In this study, within the scope of the related literature, the five forces model will be discussed in conjunction with higher education. Subsequently, the factors and evaluations that are shown within this scope will be associated with the external environmental conditions of Turkish higher education. Since there is a lack of well-written sources and sufficient data, the association with Turkish higher education will not be deeply detailed. To perceive the threats and opportunities to higher education from external environmental conditions, an overall approach will be achieved. The theoretical substructure introduced by this study will bring a different viewpoint to politicians, university directors and academicians, along with being
RECENT DEVELOPMENTS OF THE FINANCIAL REPORTING MODEL: THEORETICAL STUDIES IN REVIEW
Directory of Open Access Journals (Sweden)
Bonaci Carmen Giorgiana
2011-07-01
Full Text Available Our paper analyzes the manner in which the financial reporting model evolved towards fair value accounting. After a brief introduction into the context of financial reporting at international level, the analysis focuses on the accounting model of fair value. This is done by synthesizing main studies in accounting research literature that analyze fair value accounting through a theoretical approach. The analysis being developed relies on literature review methodology. The main purpose of the developed analysis is to synthesize main pros and cons as being documented through accounting research literature. Our findings underline both the advantages and shortcomings of fair value accounting and of the recent mixed attribute in nowadays financial reporting practices. The concluding remarks synthesize the obtained results and possible future developments of our analysis.
Directory of Open Access Journals (Sweden)
Marius Ungerer
2005-10-01
Full Text Available One of the basic assumptions associated with the theoretical model as described in this article is that an organisation (a system can acquire capabilities through intentional strategic and operational initiatives. This intentional capability-building process also implies that the organisation intends to use these capabilities in a constructive way to increase competitive advantage for the firm. Opsomming Een van die basiese aannames wat geassosieer word met die teoretiese model wat in hierdie artikel beskryf word, is dat ’n organisasie (’n stelsel vermoëns deur doelgerigte strategiese en operasionele inisiatiewe kan bekom. Hierdie voorgenome vermoë-skeppingsproses, veronderstel ook dat die onderneming daarop ingestel is om hierdie vermoëns op ’n konstruktiewe wyse te benut om die mededingende voordeel van die organisasie te verhoog.
Directory of Open Access Journals (Sweden)
Marius Ungerer
2005-10-01
Full Text Available One of the basic assumptions associated with the theoretical model as described in this article is that an organization (a system can acquire capabilities through intentional strategic and operational initiatives. This intentional capability-building process also implies that the organisation intends to use these capabilities in a constructive way to increase competitive advantage for the firm. Opsomming Een van die basiese aannames wat geassosieer word met die teoretiese model wat in hierdie artikel beskryf word, is dat ’n organisasie (’n stelsel vermoëns deur doelgerigte strategiese en operasionele inisiatiewe kan bekom. Hierdie voorgenome vermoë-skeppingsproses, veronderstel ook dat die onderneming daarop ingestel is om hierdie vermoëns op ’n konstruktiewe wyse te benut om die mededingende voordeel van die organisasie te verhoog.
The structure and dynamics of cities urban data analysis and theoretical modeling
Barthelemy, Marc
2016-01-01
With over half of the world's population now living in urban areas, the ability to model and understand the structure and dynamics of cities is becoming increasingly valuable. Combining new data with tools and concepts from statistical physics and urban economics, this book presents a modern and interdisciplinary perspective on cities and urban systems. Both empirical observations and theoretical approaches are critically reviewed, with particular emphasis placed on derivations of classical models and results, along with analysis of their limits and validity. Key aspects of cities are thoroughly analyzed, including mobility patterns, the impact of multimodality, the coupling between different transportation modes, the evolution of infrastructure networks, spatial and social organisation, and interactions between cities. Drawing upon knowledge and methods from areas of mathematics, physics, economics and geography, the resulting quantitative description of cities will be of interest to all those studying and r...
The self-schema model: a theoretical approach to the self-concept in eating disorders.
Stein, K F
1996-04-01
Over the last several decades, the self-concept has been implicated as a important determinant of eating disorders (ED). Although considerable progress has been made, questions remain unanswered about the properties of self-concept that distinguish women with an ED from other populations, and mechanisms that link the self-concept to the disordered behaviors. Markus's self-schema model is presented as a theoretical approach to explore the role of the self-concept in ED. To show how the schema model can be integrated with existing work on the self-concept in ED, a framework is proposed that addresses the number, content, and accessibility of the self-schemas. More specifically, it is posited that a limited collection of positive self-schemas available in memory, in combination with a chronically and inflexibly accessible body-weight self-schema, lead to the disordered behaviors associated with anorexia nervosa and bulimia nervosa.
A unified theoretical framework for mapping models for the multi-state Hamiltonian.
Liu, Jian
2016-11-28
We propose a new unified theoretical framework to construct equivalent representations of the multi-state Hamiltonian operator and present several approaches for the mapping onto the Cartesian phase space. After mapping an F-dimensional Hamiltonian onto an F+1 dimensional space, creation and annihilation operators are defined such that the F+1 dimensional space is complete for any combined excitation. Commutation and anti-commutation relations are then naturally derived, which show that the underlying degrees of freedom are neither bosons nor fermions. This sets the scene for developing equivalent expressions of the Hamiltonian operator in quantum mechanics and their classical/semiclassical counterparts. Six mapping models are presented as examples. The framework also offers a novel way to derive such as the well-known Meyer-Miller model.
Sharangovich, Sergey N.; Semkin, Artem O.
2017-12-01
In this work a theoretical model of the holographic formation of the polarization diffractive optical elements for the transformation of Gaussian light beams into Bessel-like ones in polymer-dispersed liquid crystals (PDLC) is developed. The model is based on solving the equations of photo-induced Fredericks transition processes for polarization diffractive elements formation by orthogonally polarized light beams with inhomogeneous amplitude and phase profiles. The results of numerical simulation of the material's dielectric tensor changing due to the structure's formation process are presented for various recording beams' polarization states. Based on the results of numerical simulation, the ability to form the diffractive optical elements for light beams transformation by the polarization holography methods is shown.
Theoretical model of two-phase drift flow on natural circulation
International Nuclear Information System (INIS)
Yang Xingtuan; Jiang Shengyao; Zhang Youjie
2002-01-01
Some expressions, such as sub-cooled boiling in the heating section, condensation near the riser inlet, flashing in the riser, and pressure balance in the steam-space, have been theoretically deduced from the physical model of 5 MW heating reactor test loop. The thermodynamics un-equilibrium etc have been considered too. A entire drift model with four equations has been formed, which can be applied to natural circulation system with low pressure and low steam quality. By means of introducing the concept of condensation layer, condensing of bubbles in the sub-cooled liquid has been formulated for the first time. The restrictive equations of the steam space pressure and liquid level have been offered. The equations can be solved by means of integral method, then by using Rung-Kutta-Verner method the final results is obtained
International Nuclear Information System (INIS)
Destombes, Jean-Luc
1978-01-01
This research thesis mainly addresses the experimental and theoretical study of the hydroxyl radical, and the consequences of the obtained results in astrophysics which are studied with a model of pumping by the far infrared. After a recall of notions related to microwave spectroscopy and to molecular radio-astronomy, the author more particularly discusses different aspects of microwave spectroscopy in the interstellar environment and in laboratory. He also reviews different types of spectrometers for unsteady molecules. In the second part, he addresses issues related to the hydroxyl radical (OH): presentation of spectrometers, study of the reaction environment, study of the radical microwave spectrum, identification of transitions by frequency measurements. In the last parts, the author addresses some aspects of interstellar OH masers, and reports the application of some results to simple models of pumping by the far infra red
Theoretical size distribution of fossil taxa: analysis of a null model
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Hughes Barry D
2007-03-01
Full Text Available Abstract Background This article deals with the theoretical size distribution (of number of sub-taxa of a fossil taxon arising from a simple null model of macroevolution. Model New species arise through speciations occurring independently and at random at a fixed probability rate, while extinctions either occur independently and at random (background extinctions or cataclysmically. In addition new genera are assumed to arise through speciations of a very radical nature, again assumed to occur independently and at random at a fixed probability rate. Conclusion The size distributions of the pioneering genus (following a cataclysm and of derived genera are determined. Also the distribution of the number of genera is considered along with a comparison of the probability of a monospecific genus with that of a monogeneric family.