Predicting Epistasis from Mathematical Models

1999 ◽  
Vol 7 (1) ◽  
pp. 69-101 ◽  
Author(s):  
Robert B. Heckendorn ◽  
Darrell Whitley
Keyword(s):  
Mathematical Models ◽  
Empirical Evidence ◽  
Sampling Error ◽  
Evaluation Function ◽  
Theoretical Interest ◽  
Exact Computation ◽  
Mathematical Expressions ◽  
Insight Into

Classically, epistasis is either computed exactly by Walsh coefficients or estimated by sampling. Exact computation is usually of theoretical interest since the computation typically grows exponentially with the number of bits in the domain. Given an evaluation function, epistasis also can be estimated by sampling. However this approach gives us little insight into the origin of the epistasis and is prone to sampling error. This paper presents theorems establishing the bounds of epistasis for problems that can be stated as mathematical expressions. This leads to substantial computational savings for bounding the difficulty of a problem. Furthermore, working with these theorems in a mathematical context, one can gain insight into the mathematical origins of epistasis and how a problem's epistasis might be reduced. We present several new measures for epistasis and give empirical evidence and examples to demonstrate the application of the theorems. In particular, we show that some functions display “parity” such that by picking a well-defined representation, all Walsh coefficients of either odd or even index become zero, thereby reducing the nonlinearity of the function.

scholarly journals Interdependence of friction, wear, and noise: A review

Friction ◽  
2021 ◽  
Author(s):  
Kevin Lontin ◽  
Muhammad Khan
Keyword(s):  
Mathematical Models ◽  
Friction And Wear ◽  
Review Paper ◽  
Acoustic Noise ◽  
Friction Noise ◽  
Mathematical Expressions ◽  
Mechanical Contacts ◽  
Exact Relationship ◽  
Modelling Approach ◽  
Frictional Noise

AbstractPhenomena of friction, wear, and noise in mechanical contacts are particularly important in the field of tribomechanics but equally complex if one wants to represent their exact relationship with mathematical models. Efforts have been made to describe these phenomena with different approaches in past. These efforts have been compiled in different reviews but most of them treated friction, wear mechanics, and acoustic noise separately. However, an in-depth review that provides a critical analysis on their interdependencies is still missing. In this review paper, the interdependencies of friction, wear, and noise are analysed in the mechanical contacts at asperitical level. The origin of frictional noise, its dependencies on contact’s mechanical properties, and its performance under different wear conditions are critically reviewed. A discussion on the existing mathematical models of friction and wear is also provided in the last section that leads to uncover the gap in the existing literature. This review concludes that still a comprehensive analytical modelling approach is required to relate the interdependencies of friction, noise, and wear with mathematical expressions.

Conceptualizing Small and Medium-Sized Smart Cities in the Mediterranean Region

2019 ◽  
Vol 8 (4) ◽  
pp. 17-41
Author(s):  
Maria Panagiotopoulou ◽  
Margarita Kokla ◽  
Anastasia Stratigea
Keyword(s):  
Empirical Evidence ◽  
Smart City ◽  
Mediterranean Region ◽  
Smart Cities ◽  
Semantic Interoperability ◽  
Spatial Context ◽  
Deep Insight ◽  
Key Drivers ◽  
The Mediterranean ◽  
Insight Into

Despite the remarkable interest in smart cities, noticed during the last decade, a consistent comprehension of the concept is not yet fully realized. Various definitions, ranging from exclusively technology-oriented perceptions to broader views, have been introduced, establishing a definitional polyphony and causing lack of semantic interoperability. Empirical evidence witnesses the prevalence of technology-pushed smart city initiatives as well as their failure to meet expectations in several urban domains. When planning “smart,” the relevance of ICT and their applications should be in alignment with spatial and other urban peculiarities and sub-systems' interactions, implying the need for getting deep insight into the city's ontology. The paper focuses on the extension/enrichment of an existing smart city ontology, with concepts and relationships stemming from Mediterranean small and medium-sized cities, in an attempt to outline their main key drivers and their interrelationships and fully grasp the smart city concept in the particular spatial context.

Decomposition of Growth Curves into Growth Rate and Acceleration: a Novel Procedure to Monitor Bacterial Growth and the Time-Dependent Effect of Antimicrobials

2021 ◽  
Author(s):  
M. Luisa Navarro-Pérez ◽  
M. Coronada Fernández-Calderón ◽  
Virginia Vadillo-Rodríguez
Keyword(s):  
Growth Rate ◽  
Mathematical Models ◽  
Bacterial Growth ◽  
Time Course ◽  
Antimicrobial Agents ◽  
Numerical Procedure ◽  
Growth Curves ◽  
Predictive Microbiology ◽  
Insight Into ◽  
Over Time

In this paper, a simple numerical procedure is presented to monitor the growth of Streptococcus sanguinis over time in the absence and presence of propolis, a natural antimicrobial. In particular, it is shown that the real-time decomposition of growth curves obtained through optical density measurements into growth rate and acceleration can be a powerful tool to precisely assess a large range of key parameters [ i.e. lag time ( t 0 ), starting growth rate ( γ 0 ), initial acceleration of the growth ( a 0 ), maximum growth rate ( γ max ), maximum acceleration ( a max ) and deceleration ( a min ) of the growth and the total number of cells at the beginning of the saturation phase ( N s )] that can be readily used to fully describe growth over time. Consequently, the procedure presented provides precise data of the time course of the different growth phases and features, which is expected to be relevant, for instance, to thoroughly evaluate the effect of new antimicrobial agents. It further provides insight into predictive microbiology, likely having important implications to assumptions adopted in mathematical models to predict the progress of bacterial growth. Importance: The new and simple numerical procedure presented in this paper to analyze bacterial growth will possibly allow identifying true differences in efficacy among antimicrobial drugs for their applications in human health, food security, and environment, among others. It further provides insight into predictive microbiology, likely helping in the development of proper mathematical models to predict the course of bacterial growth under diverse circumstances.

Three-Dimensional Aerodynamic Characteristics of Oscillating Supersonic and Transonic Annular Cascades

1982 ◽  
Author(s):  
M. Namba ◽  
A. Ishikawa
Keyword(s):  
Three Dimensional ◽  
Aerodynamic Characteristics ◽  
Aerodynamic Forces ◽  
Numerical Work ◽  
Dimensional Effects ◽  
Mathematical Expressions ◽  
Strip Theory ◽  
Clear Insight ◽  
Theory Approximation ◽  
Insight Into

A lifting surface theory is developed for unsteady three-dimensional flow in rotating subsonic, transonic and supersonic annular cascades with fluctuating blade loadings. Application of a finite radial eigenfunction series approximation not only affords a clear insight into the three-dimensional structures of acoustic fields but also provides mathematical expressions advantageous to numerical work. The theory is applied to oscillating blades. Numerical examples are presented to demonstrate three-dimensional effects on aerodynamic characteristics. Three-dimensional effects in supersonic cascades are generally small and strip theory predicts local aerodynamic forces as well as total aerodynamic forces with good accuracy. In transonic flow, however, the strip theory approximation breaks down near the sonic span station and three-dimensional effects are of primary importance.

scholarly journals On numerical solver selection and related uncertainty terminology

2009 ◽  
Vol 12 (3) ◽  
pp. 241-250 ◽  
Author(s):  
Petra Claeys ◽  
Ann van Griensven ◽  
Lorenzo Benedetti ◽  
Bernard De Baets ◽  
Peter A. Vanrolleghem
Keyword(s):  
Fluid Dynamics ◽  
Mathematical Models ◽  
Process Design ◽  
Uncertainty Assessment ◽  
Environmental Modelling ◽  
Chemical Systems ◽  
The Past ◽  
Numerical Solver ◽  
Physical And Chemical ◽  
Insight Into

Mathematical models provide insight into numerous biological, physical and chemical systems. They can be used in process design, optimisation, control and decision support, as acknowledged in many different fields of scientific research. Mathematical models do not always yield reliable results and uncertainty should be taken into account. At present, it is possible to identify some factors contributing to uncertainty, and the awareness of the necessity of uncertainty assessment is rising. In the fields of Environmental Modelling and Computational Fluid Dynamics, for instance, terminology related to uncertainty exists and is generally accepted. However, the uncertainty due to the choice of the numerical solver and its settings used to compute the solution of the models did not receive much attention in the past. A motivating example on the existence and effect of numerical uncertainty is provided and clearly shows that we can no longer ignore it. This paper introduces a new terminology to support communication about uncertainty caused by numerical solvers, so that scientists become perceptive to it.

3. Do you believe in models? Simplicity and complexity

2018 ◽  
pp. 34-47
Author(s):  
Alain Goriely
Keyword(s):  
Mathematical Modelling ◽  
Mathematical Models ◽  
Applied Mathematics ◽  
Abstract Representation ◽  
The World ◽  
Insight Into

Models are central to the world of applied mathematics. In its simplest sense, a model is an abstract representation of a system developed in order to answer specific questions or gain insight into a phenomenon. In general, we expect a model to be based on sound principles, to be mathematically consistent, and to have some predictive or insight value. Models are the ultimate form of quantification since all variables and parameters that appear must be properly defined and quantified for the equations to make sense. ‘Do you believe in models? Simplicity and complexity’ discusses the complexity of models; the steps involved in developing mathematical models—the physics paradigm; and collaborative mathematical modelling.

scholarly journals “Old Church Women”: An Insight into the Less Understood and Their Contribution to the Life of the Orthodox Church

Societies ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 63
Author(s):  
Lavinia Țânculescu
Keyword(s):  
Empirical Evidence ◽  
Crucial Role ◽  
Religious Tradition ◽  
Spiritual Identity ◽  
Orthodox Church ◽  
Advantages And Disadvantages ◽  
Romanian Orthodox Church ◽  
Romanian Orthodox ◽  
Insight Into

In this study, I aim to explore the role of old women in the life of the Christian Orthodox Church in the Romanian space. The analysis is based on empirical evidence (qualitative fieldwork and case studies) gathered between 2017 and 2019, and it mainly employs the framework of theory of tradition, and theories of attachment and of parent–infant relationship. I will show that old women going to church have a double role: To educate the community in keeping the religious tradition, and to initiate other members, especially the very young ones (blood-related or not), in the Romanian Orthodox faith. The paper discusses the advantages and disadvantages offered by both aforementioned roles, putting forth possible explanations for the tensions arising between generations. I conclude by underlining the crucial role that old women have in today’s struggle for survival of the Romanian Orthodox Church and in its spiritual identity.

scholarly journals Insight into the Links among External Business Environments, Corporate Governance and Organisational Performance

2018 ◽  
Vol 10 (1) ◽  
pp. 115
Author(s):  
Quang Linh Huynh
Keyword(s):  
Corporate Governance ◽  
Empirical Evidence ◽  
Indirect Effect ◽  
Mediating Effect ◽  
Governance Mechanism ◽  
Organisational Performance ◽  
Review Of The Literature ◽  
Business Environments ◽  
Corporate Governance Mechanism ◽  
Insight Into

The existing literature has acknowledged the complicated links among external business environments, corporate governance and organisational performance. However, a large void exists in the extant research models of corporate governance, because none have discussed and empirically examined the intervenient effect of the corporate governance mechanism on the external business environments and organisational performance. A thorough review of the literature on corporate governance, external business environments and organisational performance comes to the proposed hypotheses. The indirect effect of external business environments on organisational performance via corporate governance is statistically tested. The research provides empirical evidence that organisational performance is the consequence of both corporate governance and external business environments that is, in turn, the causality of corporate governance. More importantly, it offers insight into the mediating effect of corporate governance in transforming the uncertainty of external business environments into organisational performance. The findings suggest that firms facing uncertainty in external business environments should adopt suitable corporate governance to achieve the best organisational performance.

scholarly journals Street-connectedness and education in Kenya: Experiences of formal schooling as rationale for inclusive pedagogies of practice

Prospects ◽  
2020 ◽  
Vol 49 (3-4) ◽  
pp. 265-280
Author(s):  
Su Lyn Corcoran ◽  
Lillian Aoko Awimbo ◽  
Kelvin Mugwanga ◽  
Irene Atieno Aluoch
Keyword(s):  
Young People ◽  
Empirical Evidence ◽  
Inclusive Education ◽  
Formal Education ◽  
Original Research ◽  
Data Generation ◽  
Formal Schooling ◽  
Research Findings ◽  
Insight Into

AbstractThis article contributes to the literature on street-connectedness and inclusive education, presenting original research findings from two Kenyan studies. Both studies aim to understand street-connected young people’s experiences of education. The first focused on transitioning from the street into education or training, to explore the challenges of making that transition. The second focused on young people who had lived on the street for extended periods of time and were still there at the time of data generation. Both studies generated significant insight into (a) education as motivating initial migrations to the street, (b) the role of fear, embarrassment, and shame in preventing young people from going (back) into formal education, and (c) how acceptance and support are key to overcoming feelings of not belonging and other challenges when transitioning from the street into school. The article provides empirical evidence that should be considered when planning inclusive education provision for street-connected young people globally.

The Development of Computer Models for the Prediction of Factory Noise

1995 ◽  
Vol 2 (2) ◽  
pp. 437-454 ◽  
Author(s):  
S.M. Dance
Keyword(s):  
Mathematical Models ◽  
Ray Tracing ◽  
Computer Technology ◽  
Prediction Models ◽  
Noise Prediction ◽  
Image Source ◽  
The Past ◽  
Source Models ◽  
Insight Into ◽  
Current Potential

The development of factory noise prediction models over the past thirty years has parallelled the development of computer technology. There are currently two main approaches to this problem both of which have been extensively investigated, they are the image-source method and the ray-tracing technique. Presented are brief details of the background to the specific problems of factory noise prediction together with the various approaches used to solve the problem. An outline of how the two types of mathematical models work, together with details of their representational development is presented. A comparison of the current potential of each type of model, enabling an insight into when and where each type of model may be effectively used, is given. Three independent studies comparing various prediction models were considered. All three reviews drew the conclusion that the Ondet and Barbry, and the Lindqvist models were the most accurate ray-tracing and image-source models, respectively. Finally, a review of barrier prediction models is presented.

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