A Unified Library of Nonlinear Solution Schemes

2011 ◽  
Vol 64 (4) ◽  
Author(s):  
Sofie E. Leon ◽  
Glaucio H. Paulino ◽  
Anderson Pereira ◽  
Ivan F. M. Menezes ◽  
Eduardo N. Lages
Keyword(s):  
Nonlinear Problems ◽  
Constraint Equation ◽  
Control Algorithms ◽  
Arc Length ◽  
Unified Approach ◽  
Unified Framework ◽  
Computational Tools ◽  
Nonlinear Solution ◽  
Single Matrix ◽  
Residual Control

Nonlinear problems are prevalent in structural and continuum mechanics, and there is high demand for computational tools to solve these problems. Despite efforts to develop efficient and effective algorithms, one single algorithm may not be capable of solving any and all nonlinear problems. A brief review of recent nonlinear solution techniques is first presented. Emphasis, however, is placed on the review of load, displacement, arc length, work, generalized displacement, and orthogonal residual control algorithms, which are unified into a single framework. Each of these solution schemes differs in the use of a constraint equation for the incremental-iterative procedure. The governing finite element equations and constraint equation for each solution scheme are combined into a single matrix equation, which characterizes the unified approach. This conceptual model leads naturally to an effective object-oriented implementation. Within the unified framework, the strengths and weaknesses of the various solution schemes are examined through numerical examples.

scholarly journals Corruption, fiscal policy, and growth: a unified approach

2017 ◽  
Vol 17 (2) ◽  
Author(s):  
Sugata Ghosh ◽  
Kyriakos C. Neanidis
Keyword(s):  
Fiscal Policy ◽  
Government Spending ◽  
Income Tax ◽  
Government Expenditure ◽  
Tax Revenue ◽  
Unified Approach ◽  
Unified Framework ◽  
Bureaucratic Corruption ◽  
Inflation Rates ◽  
The Impact

AbstractWe study the effects of bureaucratic corruption on fiscal policy and economic growth, where corruption (i) reduces the tax revenue raised from households, (ii) inflates the volume of government spending, and (iii) reduces the productivity of “effective” government expenditure. We distinguish between the policies pursued by (a) a non-optimizing, and (b) an optimizing government. For both cases, corruption leads to higher income tax and inflation rates and a lower level of government spending, thus hindering growth. In the circumstances, an activist government could allocate its resources in attempting to reduce the type of corruption that harms growth the most. Finally, the findings from our unified framework could rationalize the sometimes conflicting empirical evidence on the impact of corruption on growth in the literature.

Effect of a Nonlinear Term in a Strain-Displacement Relationship on the Load-Displacement Path of Von Mises Truss

2015 ◽  
Vol 769 ◽  
pp. 85-90
Author(s):  
Jozef Havran ◽  
Martin Psotny
Keyword(s):  
Load Level ◽  
Iteration Algorithm ◽  
Arc Length ◽  
Linear Solution ◽  
Nonlinear Solution ◽  
Total Potential ◽  
Theoretical Approaches ◽  
Newton Raphson ◽  
Von Mises ◽  
Ansys System

Von Misses truss is one of the best examples to explain different theoretical approaches, nature of non-linear solution, define the snap-through, illustrate interactive buckling, etc. The presented paper compares two nonlinear approaches to the problem. Effect of nonlinear terms in strain-displacement relationship on the load level in critical point of nonlinear solution is analyzed. To obtain the nonlinear equilibrium paths, the Newton-Raphson iteration algorithm is used. Corresponding levels of the total potential energy are defined. The peculiarities of the effects of the initial imperfections are investigated. Custom FEM computer program has been used for analysis. Full Newton-Raphson procedure, in which the stiffness matrix is updated at every equilibrium iteration, has been applied. Obtained results are compared with results of the nonlinear analysis using ANSYS system, element type BEAM3 is used. The arc-length method is chosen for analysis, the reference arc-length radius is calculated from the load increment. Only fundamental path of nonlinear solution has been presented.

scholarly journals A systematic review on the current conceptualisations of successful psychopathy

2020 ◽  
Author(s):  
Louise Wallace ◽  
Nadja Heym ◽  
Alexander Sumich ◽  
Dean Fido
Keyword(s):  
Systematic Review ◽  
Systematic Research ◽  
Key Factors ◽  
Unified Approach ◽  
Unified Framework ◽  
Exclusion Criteria ◽  
Definition Of Success ◽  
Definition Of ◽  
General Populations ◽  
Levels Of Functioning

The concept of successful psychopathy has been debated for years, however, there is yet no unified approach to its definition and conceptualisation. Such individuals are said to encompass the core traits associated with psychopathy, whilst continuing to function in society, potentially having superior levels of functioning. This review assimilates the existing literature related to successful psychopathy in the general population. An extensive systematic review was performed using four databases, and two key concepts; namely success and psychopathy. After removing duplicates and articles deemed irrelevant, 180 papers were appraised against the review’s inclusion and exclusion criteria. The remaining 19 papers underwent quality control by two raters. A narrative synthesis was performed. The key factors associated with the successful psychopathy construct were fearlessness, stress immunity, social potency, normal or superior cognitive performance, professional achievement, stable socioeconomic status, leadership, pride, and aversion to punishment during conflict. Inconsistent findings were considered a result of the variations in psychopathy measurements used, and a lack of an agreed definition of success. Recommendations are provided for the establishment of a unified framework, and the need for a moderated measure of successful psychopathy to allow more systematic research into the notion of successful psychopathy in the general populations.

The Generation of Contact Surfaces of Indexing Cam Mechanisms: A Unified Approach

1990 ◽  
Author(s):  
M. A. Gonzalez-Palacios ◽  
J. Angeles ◽  
Ch. Cai
Keyword(s):  
Angular Velocity ◽  
Velocity Ratio ◽  
Rigid Bodies ◽  
Ruled Surfaces ◽  
Time Varying ◽  
Unified Approach ◽  
Unified Framework ◽  
Spatial Mechanisms ◽  
Contact Surfaces

Abstract In this paper the ruled surfaces of two rigid bodies that are in contact while moving with a prescribed time-varying angular-velocity ratio are generated. These are then used as the contact surfaces of indexing cam mechanisms. In this way, planar, spherical and spatial mechanisms can be synthesized in a unified framework. The approach is illustrated with various examples.

scholarly journals Universal motifs and the diversity of autocatalytic systems

2020 ◽  
Vol 117 (41) ◽  
pp. 25230-25236 ◽  
Author(s):  
Alex Blokhuis ◽  
David Lacoste ◽  
Philippe Nghe
Keyword(s):  
Kinetic Analysis ◽  
Chemical Evolution ◽  
Systematic Study ◽  
Reaction Networks ◽  
Unified Approach ◽  
Unified Framework ◽  
Basic Principles ◽  
The Origin Of Life ◽  
Catalytic Cycles

Autocatalysis is essential for the origin of life and chemical evolution. However, the lack of a unified framework so far prevents a systematic study of autocatalysis. Here, we derive, from basic principles, general stoichiometric conditions for catalysis and autocatalysis in chemical reaction networks. This allows for a classification of minimal autocatalytic motifs called cores. While all known autocatalytic systems indeed contain minimal motifs, the classification also reveals hitherto unidentified motifs. We further examine conditions for kinetic viability of such networks, which depends on the autocatalytic motifs they contain and is notably increased by internal catalytic cycles. Finally, we show how this framework extends the range of conceivable autocatalytic systems, by applying our stoichiometric and kinetic analysis to autocatalysis emerging from coupled compartments. The unified approach to autocatalysis presented in this work lays a foundation toward the building of a systems-level theory of chemical evolution.

A Unified Approach to Linear Equating for the Nonequivalent Groups Design

2005 ◽  
Vol 30 (3) ◽  
pp. 313-342 ◽  
Author(s):  
Alina A. von Davier ◽  
Nan Kong
Keyword(s):  
General Formula ◽  
Standard Error ◽  
Unified Approach ◽  
Unified Framework ◽  
Neat Design ◽  
Nonequivalent Groups ◽  
Standard Error Of Equating ◽  
Observed Score ◽  
Special Case ◽  
Linear Equating

This article describes a new, unified framework for linear equating in a non-equivalent groups anchor test (NEAT) design. The authors focus on three methods for linear equating in the NEAT design—Tucker, Levine observed-score, and chain—and develop a common parameterization that shows that each particular equating method is a special case of the linear equating function in the NEAT design. A new concept, the method function, is used to distinguish among the linear equating functions, in general, and among the three equating methods, in particular. This approach leads to a general formula for the standard error of equating for all linear equating functions in the NEAT design. A new tool, the standard error of equating difference , is presented to investigate if the observed difference in the equating functions is statistically significant.

scholarly journals Autocatalysis in Chemical Networks: Unifications and Extensions

2020 ◽  
Author(s):  
Alex Blokhuis ◽  
David Lacoste ◽  
Philippe Nghe
Keyword(s):  
Kinetic Analysis ◽  
Chemical Evolution ◽  
Chemical Reaction ◽  
Systematic Study ◽  
Reaction Networks ◽  
Essential Property ◽  
Unified Approach ◽  
Unified Framework ◽  
Basic Principles

Autocatalysis is an essential property for theories of abiogenesis and chemical evolution. However, the different formalisms proposed so far seemingly address different forms of autocatalysis and it remains unclear whether all of them have been captured. Furthermore, the lack of unified framework thus far prevents a systematic study of autocatalysis. Here, we derive general stoichiometric conditions for catalysis and autocatalysis in chemical reaction networks from basic principles in chemistry. This allows for a classification of minimal autocatalytic motifs, which includes all known autocatalytic systems and motifs that had not been reported previously. We further examine conditions for kinetic viability of such networks, which depends on the autocatalytic motifs they contain. Finally, we show how this framework extends the range of conceivable autocatalytic systems, by applying our stoichiometric and kinetic analysis to autocatalysis emerging from coupled compartments. The unified approach to autocatalysis presented in this work lays a foundation towards the building of a systems-level theory of chemical evolution.<br>

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