Search

This paper proposes a simple and fast method to obtain the aeroelastic response of a square cylinder following different modelling approaches underpinned by a novel graphical technique that establishes abstract relationships between different key physical parameters involved in the mathematical models. The method is applied to the analysis of three important aeroelastic problems in the crosswind response of a square cylinder, including the transverse galloping defined with a quasi-steady model, the vortex-induced vibration (VIV) using a nonlinear oscillator model, and the VIV-galloping interaction following a combined effects model. The results demonstrate that the proposed analytical method simplifies the analysis and it is able to capture most of the complex aeroelastic crosswind behaviors of a square bluff body. • A graphical method to obtain the aeroelastic response of a square cylinder following different modelling approaches is proposed. • Compared with conventional analytical methods, the new analytical method has advantages of simplicity and effectiveness. • The graphical analytical method is successfully applied to the study of transverse galloping, VIV and their potential interaction. [ABSTRACT FROM AUTHOR]

It is known that the one-dimensional (1D) compression behavior is commonly represented by the e-logp' curve, which is obtained from the oedometer test. Five numbers of mathematical models were adopted to best fit the experimental data from the consolidation test. It is observed that Fredlund and Xing (1994)'s (FX) model, which is commonly used for the representation of the soil–water characteristic curve (SWCC), gives the best performance in best fitting the experimental data of e-logp' curves. Subsequently, the graphical method is adopted to determine the pre-consolidation pressure (Pc) by adopting FX model. Consequently, the equations are proposed for the determination of the Pc of the soil from the fitting parameters in FX model. The proposed method provides an alternative method for the determination of the Pc. [ABSTRACT FROM AUTHOR]

A great circle route (GCR) is the shortest route on a spherical earth model. Do we have a visual diagram to handle the shortest route? In this paper, a graphical method (GM) is proposed to solve the GCR problems based on the celestial meridian diagram (CMD) in celestial navigation. Unlike developed algebraic methods, the GM is a geometric method. Appling computer software to graph, the GM does not use any equations but is as accurate as using algebraic methods. In addition, the GM, which emphasizes the rotational surface, can depict a GCR and judge its benefit. [ABSTRACT FROM AUTHOR]

Abstract: Following specification of all variables of interest as well as their interrelationships, the validity of an ecological model (or of any of its components) is often tested by analysis of variance (ANOVA)-based procedures, either through experimentation, ‘screening’ of predictors, or simulation. To this end, the linear model diagram (LMD) is introduced as a graphical method for the display of factor relationships in ANOVA balanced complete designs. As an analysis-oriented diagram, hence in contrast with layout-oriented diagrams useful for the allocation of experimental units to factor levels (or vice versa), the purpose of the LMD is to streamline specification of a design''s underlying linear model. This contains all available information about each observation and its correct specification is essential for computing reliable ANOVA error terms. In the LMD, factor relationships, especially higher order interactions in complex fully factorial or nested/factorial designs, are more effectively visualised than in the other existing analysis-oriented diagrams. Further, by assigning a unique label to a design, including those sharing an otherwise identical linear model, the LMD provides the ecologist with a graphic ‘shorthand’ that streamlines the statistical analysis of an experiment as well as may help clarify terminological inconsistencies. [Copyright &y& Elsevier]

Background: Derivative based a-priori structural identifiability analyses of mathematical models can offer valuable insight into the identifiability of model parameters. However, these analyses are only capable of a binary confirmation of the mathematical distinction of parameters and a positive outcome can begin to lose relevance when measurement error is introduced. This article presents an integral based method that allows the observation of the identifiability of models with two-parameters in the presence of assay error. Methods: The method measures the distinction of the integral formulations of the parameter coefficients at the proposed sampling times. It can thus predict the susceptibility of the parameters to the effects of measurement error. The method is tested in-silico with Monte Carlo analyses of a number of insulin sensitivity test applications. Results: The method successfully captured the analogous nature of identifiability observed in Monte Carlo analyses of a number of cases including protocol alterations, parameter changes and differences in participant behaviour. However, due to the numerical nature of the analyses, prediction was not perfect in all cases. Conclusions: Thus although the current method has valuable and significant capabilities in terms of study or test protocol design, additional developments would further strengthen the predictive capability of the method. Finally, the method captures the experimental reality that sampling error and timing can negate assumed parameter identifiability and that identifiability is a continuous rather than discrete phenomenon. [ABSTRACT FROM AUTHOR]

The monkeypox virus (MPXV) has caused an unusual epidemiological scenario—an epidemic within a pandemic (COVID-19). Despite the inherent evolutionary and adaptive capacity of poxviruses, one of the potential triggers for the emergence of this epidemic was the change in the status of orthopoxvirus vaccination and eradication programs. This epidemic outbreak of HMPX spread worldwide, with a notable frequency in Europe, North America, and South America. Due to these particularities, the objective of the present study was to assess and compare cases of HMPX in these geographical regions through logistic and Gompertz mathematical modeling over one year since its inception. We estimated the highest contagion rates (people per day) of 690, 230, 278, and 206 for the world, Europe, North America, and South America, respectively, in the logistic model. The equivalent values for the Gompertz model were 696, 268, 308, and 202 for the highest contagion rates. The Kruskal–Wallis Test indicated different means among the geographical regions affected by HMPX regarding case velocity, and the Wilcoxon pairwise test indicated the absence of significant differences between the case velocity means between Europe and South America. The coefficient of determination (R2) values in the logistic model varied from 0.8720 to 0.9023, and in the Gompertz model, they ranged from 0.9881 to 0.9988, indicating a better fit to the actual data when using the Gompertz model. The estimated basic reproduction numbers ( R 0 ) were more consistent in the logistic model, varying from 1.71 to 1.94 in the graphical method and from 1.75 to 1.95 in the analytical method. The comparative assessment of these mathematical modeling approaches permitted the establishment of the Gompertz model as the better-fitting model for the data and the logistic model for the R 0 . However, both models successfully represented the actual HMPX case data. The present study estimated relevant epidemiological data to understand better the geographic similarities and differences in the dynamics of HMPX. [ABSTRACT FROM AUTHOR]

The potential of using differences in log crude mortality rates, matched age for age, as a simple means of comparing two mortality studies is investigated. Graphical displays of such differences, plotted against age, are advocated and a method of curve fitting described. A number of applications are presented, and the results of this approach compared with known results, where available. Copyright © 1999 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

For single-phase grid-connected inverters, the second-order generalized integrator-based phase-locked loop (SOGI-PLL) is widely used for good harmonics attenuation and frequency adaptability. However, existing studies usually neglect the frequency feedback loop in the modeling and design process, and thus, the potential instability caused by the frequency feedback loop is not well explained. Besides, the improper design of SOGI-PLL can lead to the inverter instability both under ideal and weak grid conditions. Therefore, by fully considering the coupling of the frequency feedback loop, this article establishes an accurate model for SOGI-PLL. Furthermore, effects of different PLL parameters on behaviors of both the SOGI-PLL itself and the inverter are studied, based on which a graphical method for PLL parameters design is proposed. As proved, the frequency feedback loop can deteriorate the stability and performance of both SOGI-PLL itself and inverter system, especially if rapid transient is expected. The modeling method is also extended to the low-pass filter-SOGI-PLL and the improved parameters design is discussed. Experimental results verify the correctness of the proposed PLL model and the abovementioned analysis results. The proposed model is helpful to deeply reveal the instability mechanism and provides a reference for the PLL design under nonideal grid conditions. [ABSTRACT FROM AUTHOR]

Azeotropic distillation as an early and important special distillation process is commonly used in laboratory and industry. It can be used for separating the mixture with close boiling point or forming azeotrope. This paper tries to provide a review on azeotropic distillation for general readers, focusing on entrainer selection and mathematical models. Since the 1950s, along with extractive distillation, azeotropic distillation has gained a wide attention. Like extractive distillation, the entrainer, i.e., the third component added to the system, is also the core of azeotropic distillation. In the process design and synthesis, the graphical method (in most cases refer to as triangular diagram) is often employed. But it is better to take on the results from graphical method as the initial values of rigorous equilibrium (EQ) stage/non-equilibrium (NEQ) stage models. One outstanding characteristic of the EQ/NEQ stage models different from extractive distillation and catalytic distillation is to describe phase split for heterogeneous azeotropic distillation. In general, the operation process is very sensitive to some parameters in the case of more than one azeotrope formed, and thus the phenomenon of multiple steady states (MSS) tends to appear. [ABSTRACT FROM AUTHOR]

The lifetimes of polar optical phonons are known to affect both the electrical and thermal performances of gallium nitride (GaN) based devices. Hence, understanding the dynamical behavior of these phonons in GaN is integral to the elucidation of carrier drift velocities, hot phonon effects, and temperature localization in these nitride semiconductors. To investigate this dynamic behavior, temperature dependent phonon lifetimes were acquired through utilization of the linewidth of the Raman response for GaN samples having various doping types and concentrations. The temperature dependent lifetimes of the four examined phonon modes were then correlated with the Klemens decay model modified to account for four-phonon processes to deduce the decomposition of the zone center phonons. A graphical method that maps this decomposition in the high symmetry directions of the Brillouin zone is also presented. From the variation in lifetime with free carrier concentration, dominant scattering mechanisms are subsequently found for each of four different phonon modes. It is observed that the phonon-carrier interaction directly determines the lifetimes of the polar optical A1 and E1(LO) modes, while the transverse modes into which these longitudinal phonons decay are independent of this interplay. These results indicate that temperature localization likely arises due to the continual emission and reabsorption between the LO phonon modes and the free carriers rather than the persistence of lattice/carrier interaction throughout the entirety of the energy cascade. [ABSTRACT FROM AUTHOR]

Orbital flybys have been extensively studied for spacecraft missions, resulting in effective mathematical and physical models. However, these models' applicability to natural encounters involving asteroids has not been explored. This paper examines the applicability of two such theories, patched conics (PC) and the Keplerian map (KM), to asteroid encounters. A review of the two methods will be provided, highlighting their assumptions and range of applicability. Simulations of asteroid–asteroid encounters will then be performed to evaluate their effectiveness in these scenarios. The simulation parameters are set by collecting data on actual asteroid–asteroid encounters, hereby presented, generally characterised by high close approach distances and small masses of the perturbing bodies, if compared to those used to build the flyby theories. Results show that the PC theory's effectiveness diminishes with increasing approach distances, aligning with its assumptions. Moreover, the prediction of the model is better in the geometric configurations where the flyby has major effects on the orbital energy change. The KM theory has shown good effectiveness for encounters occurring outside the sphere of influence of the perturbing body, even for very high distances. This research investigates flyby models' strengths and weaknesses in asteroid encounters, offering practical insights and future directions. [ABSTRACT FROM AUTHOR]

The object of this study is the deformation of multilayer ellipsoidal shells under non-stationary distributed load. It is proposed to reinforce the shell with longitudinal stiffeners to enhance the strength of it. The application of Timoshenko’s theory of shells and cores enabled the investigation of the influence of longitudinal stiffeners on the deformation of multilayer ellipsoidal shells under non-stationary loads with the discrete positioning of the stiffeners. A mathematical model of shell oscillations under various types of short-term non-stationary loads was based on the Hamilton-Ostrogradsky variational principle. The numerical algorithm based on the application of the integral-interpolation approach to the construction of finite difference schemes in spatial coordinates, combined with an explicit finite-difference scheme for the time coordinate, was used to solve the task set. It has been determined that reinforcing stiffeners significantly affect the deformed state of the multilayer ellipsoidal shell. The “shell-stiffeners” relation was taken into account as a base for research. The maximum deformation ε11 of the smooth three-layer ellipsoidal shell was on average 1.4 times greater than the deformation ε11 of the reinforced three-layer ellipsoidal shell throughout the entire studied time interval. It was determined that over time the presence of reinforcing stiffeners has a more significant impact on the deformed state of the reinforced ellipsoidal shell. A distinctive feature of this research is the consideration of the discrete placement of reinforcing stiffeners which made it possible to investigate the impact of longitudinal stiffeners on the deformation of multilayer ellipsoidal shells under non-stationary loads. The results could be used for the investigation of applied problems in research organizations and design bureaus when designing shell structures [ABSTRACT FROM AUTHOR]

The usual t-test or F-test can not be used to analyze unreplicated two-level factorial designs, since all the observations are used to estimate the factor effects and no observation is left to estimate the error variance. To overcome this difficulty, various procedures have been proposed in the literature and several simulation studies have been carried out to compare the performance of these methods. The results of these studies have been inconclusive, and no test is widely accepted as a "best" test. In this paper, we present results that show theoretically that no test has high power against all possible alternatives; i.e. no test can detect all patterns of active effects. Therefore, in the absence of any prior information concerning active and inactive effects, no test can be preferred to any other test based on power and the choice of a test should be based on other considerations, such as ease of use, control of individual or experimental error rate, the purpose of the experiment, etc. [ABSTRACT FROM AUTHOR]

The article analyzes a concentration-mass load diagram to determine the effect of decomposition on water use and on the regeneration reuse water system (RRWS). Several sequential mathematical models and a superstructure are developed and evaluated in their capacity to optimize single contaminant RRWS. In addition, a graphical method is used to assess the performance of decomposition strategies.

Generalized functions, in particular the Heaviside unit step H(t) and the Dirac delta impulse δ(t), are valuable teaching tools in many contexts of electric circuits. However, engineering undergraduate courses and textbooks normally cover only an introduction to these functions along with their basic properties, without tackling the rigorous mathematical framework of the theory of distributions. In this work, the Heaviside function is used to represent a square wave signal f(t), and the Dirac function appears when the derivative is calculated. The steps for obtaining f'(t) compare a graphical method with analytical procedures that employ the chain rule. The topic is further extended with the presentation of a theorem and a proposed corollary related to the study of the chain rule applied to general functions involving H(t) and δ(t). Thus, the work provides an appropriate mathematical support for the intuitive graphical method of analysis, which is very familiar in engineering practice. [ABSTRACT FROM AUTHOR]

This paper describes a semiparametric method for estimating a generic probability distribution using a basis expansion in. We express the given distribution as a monotonic transformation of the Gaussian cumulative distribution function, expanded in a basis of Hermite polynomials. The coefficients in the basis expansion are functionals of the quantile function, and can be consistently estimated to give a smooth estimate of the transformation function. For situations in which the estimated function is not monotone, a projection approach is used to adjust the estimated transformation function to guarantee monotonicity. Two applications are presented which focus on the analysis of model residuals. The first is a data example which uses the residuals from the 2012 Small Area Income and Poverty Estimates model. The Hermite estimation method is applied to these residuals as a graphical method for detection of departures from normality and to construct credible intervals. The second example analyses residuals from time series models for the purpose of estimating the variance of the mean and median and comparing the results to the AR-sieve. This paper concludes with a set of numerical examples to illustrate the theoretical results. [ABSTRACT FROM AUTHOR]

The transient characteristics of proton exchange membrane water electrolysis for hydrogen production are crucial for the study of the load control and durability of the electrolyzer under the fluctuating conditions of renewable energy sources. In this study, a dynamic model of the electrolyzer is established based on various equivalence theories used to describe the transient characteristics of the electrolyzer during operation. Differential-equation-based transient models of the R C (resistance and capacitance) equivalent circuit and the equivalent controlled current source, their advantages and disadvantages, and their typical transient response spectra are presented. Among these, the graphical method based on the polarization curve is recommended because it has the advantages of intuitive and simple expression and can help researchers precisely and efficiently predict the response form and time of current or voltage using various control methods. The transient characteristics of the shutdown process reflect electrochemical processes similar to those of fuel cells in the electrolyzer during the OCV (open circuit voltage) period. The performance of the transient process is related to the structure of the electrolyzer and the operating conditions of the measurement. Low-voltage sustenance with manual intervention following shutdown may have a positive effect on the durability of the electrolyzer. • The transient characteristics of load regulation and shutdown are described. • Mathematical models based on differential equations are reviewed and summarized. • Different control methods are compared using the graphical method. • The 'voltage sustaining' after shutdown is measured and explained. [ABSTRACT FROM AUTHOR]

Aim. Through the present research, we aim to bring to the fore a problem regarding a less studied aspect, namely the so-called peak experiences and their connection with sports games. Methods. For our research we involved students from the Petroleum-Gas University, Ploieşti. We have to mention that Physical Education is a compulsory subject for students being in the first and second years of study, and it is enclosed in the university curriculum. The present research has been undertaken on a group of 93 randomly chosen students (capable for physical effort) and who, at least theoretically, have the same level of education. From the 93 students, in the second part of the lesson - 70 subjects systematically practice a chosen sports game and the other 23 subjects prefer the alternative of jogging for a physical exercise. The bibliographic study method; The observation method; The enquiry method (conversation, a questionnaire entitled "The Scale of Peak Experiences", etc.); The statistical-mathematical method; The graphical method. Results. For the research, we started from the hypothesis according to which in the top of the pyramid we have the updating of the self, in order to have the so-called peak experiences, which are generally accompanied by happiness or intense joy, which may be experienced intensely especially where sports games with goals scoring are practiced, meaning with the finalization which triggers those intense feelings of satisfaction, hence peak experiences, as in its absence we do not have the triggering effect for peak experiences. Conclusions: Peak experiences may occur especially where the sports game retains the supremacy and upgrades the self, in order to have the so-called peak experiences. [ABSTRACT FROM AUTHOR]

The economic benefit gained from a combined cooling heating and power (CCHP) system depends on many factors. It is essential to optimize the system configuration and operational scheme as early in the design stage as possible. In this paper, a sizing optimization model (SOM) focused on the minimum annual total cost ( ATC ) and an operational optimization model (OOM) focused on the minimum annual energy charge ( AEC ) were established. The former was used to determine the optimal capacity of a CCHP system, whereas the latter was used to provide the optimal schemes. Both the SOM and OOM contain large numbers of hourly linear programming (LP) models, and the solution processes of both models proved to be quite time-consuming when the conventional iterative method was used. In this study, a piecewise elimination method was proposed for hourly LP models, and a graphical method in which the iteration was converted to an algebraic matrix was introduced to greatly improve the computational efficiency. The results demonstrated that the calculation time was reduced from 84.496 s for the conventional solution to 0.017 s for the graphical method in the OOM. The CCHP system SOM contains an OOM, and the calculation time was only 0.41 s when using the graphical method, whereas the conventional iterative method took 2367 s. The impact of gas price upon the optimal operational schemes and the equipment capacity was discussed for a building application in Shanghai. The improved efficiency of the calculation method could be helpful to compare different schemes and to perform sensitivity analyses. [ABSTRACT FROM AUTHOR]

Simple Summary: The research aimed to address the challenges in the early diagnosis of Oral Squamous Cell Carcinoma (OSCC), a critical concern given its high fatality rate and global prevalence. Through the development of hybrid methodologies, the study sought to improve early diagnosis, reduce the burden on pathologists, and enhance the accuracy of OSCC diagnosis. By employing transfer learning, a combination of CNN and SVMs, and a fusion of deep and texture-based features, the research achieved a significant overall accuracy of 97.00%, effectively addressing the critical problem of timely and accurate OSCC diagnosis. Oral cancer is a fatal disease and ranks seventh among the most common cancers throughout the whole globe. Oral cancer is a type of cancer that usually affects the head and neck. The current gold standard for diagnosis is histopathological investigation, however, the conventional approach is time-consuming and requires professional interpretation. Therefore, early diagnosis of Oral Squamous Cell Carcinoma (OSCC) is crucial for successful therapy, reducing the risk of mortality and morbidity, while improving the patient's chances of survival. Thus, we employed several artificial intelligence techniques to aid clinicians or physicians, thereby significantly reducing the workload of pathologists. This study aimed to develop hybrid methodologies based on fused features to generate better results for early diagnosis of OSCC. This study employed three different strategies, each using five distinct models. The first strategy is transfer learning using the Xception, Inceptionv3, InceptionResNetV2, NASNetLarge, and DenseNet201 models. The second strategy involves using a pre-trained art of CNN for feature extraction coupled with a Support Vector Machine (SVM) for classification. In particular, features were extracted using various pre-trained models, namely Xception, Inceptionv3, InceptionResNetV2, NASNetLarge, and DenseNet201, and were subsequently applied to the SVM algorithm to evaluate the classification accuracy. The final strategy employs a cutting-edge hybrid feature fusion technique, utilizing an art-of-CNN model to extract the deep features of the aforementioned models. These deep features underwent dimensionality reduction through principal component analysis (PCA). Subsequently, low-dimensionality features are combined with shape, color, and texture features extracted using a gray-level co-occurrence matrix (GLCM), Histogram of Oriented Gradient (HOG), and Local Binary Pattern (LBP) methods. Hybrid feature fusion was incorporated into the SVM to enhance the classification performance. The proposed system achieved promising results for rapid diagnosis of OSCC using histological images. The accuracy, precision, sensitivity, specificity, F-1 score, and area under the curve (AUC) of the support vector machine (SVM) algorithm based on the hybrid feature fusion of DenseNet201 with GLCM, HOG, and LBP features were 97.00%, 96.77%, 90.90%, 98.92%, 93.74%, and 96.80%, respectively. [ABSTRACT FROM AUTHOR]

Mathematical modeling and computer simulation are tools of great importance for the development of fuel cells. Thus, the objective of this work is to carry out the kinetic modeling of glycerol oxidation in a DGFC (direct glycerol fuel cell), considering two different approaches: (1) realistic phenomenological models for the partial oxidation of glycerol in Pt/C, considering its adsorbed intermediates; (2) models of artificial neural networks (ANN—artificial neural networks) for oxidation mainly of PtAg/C and PtAg/MnOx/C. The models were fitted to experimental data already available for validation and determination of their parameters, both using Matlab software, v. R2018a (MathWorks, Natick, MA, USA). Results for the phenomenological models developed showed excellent fits for the polarization curve, with an RMSE (root mean squared error) value on the order of 0.352 to 0.404 mA/cm2, in addition to coverage fractions consistent with the literature for the adsorbed species. The kinetic parameters with the greatest influence on the response of the models were those associated with the consumption of glyceric acid and the formation of tartronic acid and with the dissociative adsorption of water and the formation of Pt-Oads active sites. Regarding the neural models, excellent prediction fits were obtained for all of them, with RMSE values on the order of 0.008 to 0.014 mA/cm2, indicating the possibility of representing the functional interdependence between input variables and the density cell current for cases where it would be too complex to do so via mechanistic modeling (i.e., for PtAg/C and PtAg/MnOx/C oxidation). [ABSTRACT FROM AUTHOR]

This study focuses on optimizing the foundation pit dewatering scheme using the foundation pit dewatering theory and the principles of multi-objective optimization. It explores the development of a multi-objective optimization model and efficient solution technology for foundation pit dewatering. This research focuses on the foundation pit dewatering project at the inverted siphon section of Xixiayuan canal head, specifically from pile number XZ0+326 to XZ0+500. It establishes an optimized mathematical model for foundation pit dewatering that incorporates three objectives. Additionally, a dewatering optimization program is developed by utilizing the MATLAB optimization toolbox and the multi-objective optimization algorithm program based on the NSGA-II algorithm (Gamultiobj). The multi-objective optimization mathematical model is solved, and a Pareto-optimal solution set with uniform distribution is obtained. The multi-objective optimization evaluation system based on AHP is constructed from the three aspects of dewatering cost, the impact of settlement on the environment, and the safety and stability of the foundation pit. The optimization scheme of the Pareto-optimal solution set is selected as the decision result to provide multiple feasible schemes for the dewatering construction of foundation pits. The optimization scheme is verified by using the GMS software. The simulation results demonstrate that the optimization scheme fulfills the requirements for water level and settlement control. Moreover, the developed optimization program efficiently solves the multi-objective optimization problem associated with foundation pit dewatering. Lastly, an evaluation system incorporating the NSGA-II algorithm and AHP is developed and utilized in the context of dewatering engineering in order to offer multiple viable optimal dewatering schemes. [ABSTRACT FROM AUTHOR]

Introducing purification devicesinto hydrogen systems can enhancethe extent of hydrogen reuse. The economic performance of a purificationdevice depends on its appropriate placement within a hydrogen system.This work presents an improved version of a previously published graphicalmethod for integrating purification processes in hydrogen systems.A mathematical method is deduced for calculating the maximum hydrogenutility savings potential of a hydrogen system with purification reuse.The improved graphical method is able to handle the constraints ofconcentration and flow rate of a purification process when targetingthe maximum hydrogen utility savings. The proposed method can be usedfor analyzing purification processes with any feed concentration.The graphical method is tested on two case studies. [ABSTRACT FROM AUTHOR]

We present an approach for quantitative trait locus (QTL) mapping, termed as 'lineage-specific QTL mapping', for inferring allelic changes of QTL evolution along with branches in a phylogeny. We describe and analyze the simplest case: by adding a third taxon into the normal procedure of QTL mapping between pairs of taxa, such inferences can be made along lineages to a presumed common ancestor. Although comparisons of QTL maps among species can identify homology of QTLs by apparent co-location, lineage-specific mapping of QTL can classify homology into (1) orthology (shared origin of QTL) versus (2) paralogy (independent origin of QTL within resolution of map distance). In this light, we present a graphical method that identifies six modes of QTL evolution in a three taxon comparison. We then apply our model to map lineage-specific QTLs for inbreeding among three taxa of yellow monkey-flower: Mimulus guttatus and two inbreeders M. platycalyx and M. micranthus, but critically assuming outcrossing was the ancestral state. The two most common modes of homology across traits were orthologous (shared ancestry of mutation for QTL alleles). The outbreeder M. guttatus had the fewest lineage-specific QTL, in accordance with the presumed ancestry of outbreeding. Extensions of lineage-specific QTL mapping to other types of data and crosses, and to inference of ancestral QTL state, are discussed. [ABSTRACT FROM AUTHOR]

Plant-soil feedbacks can have important implications for the interactions among plants. Understanding these effects is a major challenge since it is inherently difficult to measure and manipulate highly diverse soil communities. Mathematical models may advance this understanding by making the interplay of the various processes affecting plant-soil interaction explicit and by quantifying the relative importance of the factors involved. The aim of this paper is to provide a complete analysis of a pioneering plant-soil feedback model developed by Bever and colleagues (J Ecol 85: 561-573, ; Ecol Lett 2: 52-62, ; New Phytol 157: 465-473, ) to fully understand the range of possible impacts of plant-soil feedbacks on plant communities within this framework. We analyze this model by means of a new graphical method that provides a complete classification of the potential effects of soil communities on plant competition. Due to the graphical character of the method, the results are relatively easy to obtain and understand. We show that plant diversity depends crucially on two key parameters that may be viewed as measures of the intensity of plant competition and the direction and strength of plant-soil feedback, respectively. Our analysis provides a formal underpinning of earlier claims that plant-soil feedbacks, especially when they are negative, may enhance the diversity of plant communities. In particular, negative plant-soil feedbacks can enhance the range of plant coexistence by inducing competitive oscillations. However, these oscillations can also destabilize plant coexistence, leading to low population densities and extinctions. In addition, positive feedbacks can allow locally stable forms of plant coexistence by inducing alternative stable states. Our findings highlight that the inclusion of plant-soil interactions may fundamentally alter the predictions on the structure and functioning of above-ground ecosystems. The scenarios presented in this study can be used to formulate hypotheses about the ways soil community effects may influence plant competition that can be tested with empirical studies. This will advance our understanding of the role of plant-soil feedback in ecological communities. [ABSTRACT FROM AUTHOR]

The problem of pumps connected in parallel can be easily solved by means of graphical method, but it becomes very time consuming when dealing with multiple scenarios. An analytical approach offers the possibility of implementing a software program that can significantly reduce this time and also adds further features. The mathematical algorithm used is dealing with a nonlinear equitation system and with polynomial fitting functions. A very special issue that is addressed in this paper is about the errors given by the very small values of flow rates. Since the algorithms assume that every physical measure is expressed in SI units, then the unitless values of flow rates are at least 10-3 magnitude order compared to other values (pump head for example). This in turn leads to very poor fitting polynomials and the end results are far from the truth. The key for solving this particular issue resides in constructing the inverse functions of H(Q). Once the algorithms were sort out, they were implemented in LabVIEW in order to create a software application. This final product offers both accuracy of the calculations and user friendly interface. [ABSTRACT FROM AUTHOR]

Mental models are poorly specified in three ways: in their defining criteria, their source and the bias to which they have been subjected. Literature from psychology, HCI and human factors sources was reviewed to determine the utility of ‘mental models’ as a design tool. The definitions and theories offered by key contributors to the notion of mental models were compared. Schematics, representing both the knowledge structures proposed in cognitive processing, as well as the layers of bias evident when forming or accessing mental models, were constructed. Fundamental similarities and differences in the use of this notion, as well as ambiguities in definition, were highlighted graphically. The need for specificity in the use of mental models was emphasised as essential for pragmatic application in design. The use of graphical comparison was proposed as a means of identifying the risk of bias and a means to categorise approaches to mental model research. Practitioner Summary: Mental models are considered significant in user centred design. To apply this notion pragmatically, its definition and methods of construction and access need to be sufficiently specified. This article offers a graphical method to compare existing research in mental models, highlighting similarities, differences and ambiguities. [ABSTRACT FROM PUBLISHER]

In terms of its soluble precursors, the coagulation proteome varies quantitatively among apparently healthy individuals. The significance of this variability remains obscure, in part because it is the backdrop against which the hemostatic consequences of more dramatic composition differences are studied. In this study we have defined the consequences of normal range variation of components of the coagulation proteome by using a mechanism-based computational approach that translates coagulation factor concentration data into a representation of an individual's thrombin generation potential. A novel graphical method is used to integrate standard measures that characterize thrombin generation in both empirical and computational models (e.g max rate, max level, total thrombin, time to 2 nM thrombin ("clot time")) to visualize how normal range variation in coagulation factors results in unique thrombin generation phenotypes. Unique ensembles of the 8 coagulation factors encompassing the limits of normal range variation were used as initial conditions for the computational modeling, each ensemble representing "an individual" in a theoretical healthy population. These "individuals" with unremarkable proteome composition was then compared to actual normal and "abnormal" individuals, i.e. factor ensembles measured in apparently healthy individuals, actual coagulopathic individuals or artificially constructed factor ensembles representing individuals with specific factor deficiencies. A sensitivity analysis was performed to rank either individual factors or all possible pairs of factors in terms of their contribution to the overall distribution of thrombin generation phenotypes. Key findings of these analyses include: normal range variation of coagulation factors yields thrombin generation phenotypes indistinguishable from individuals with some, but not all, coagulopathies examined; coordinate variation of certain pairs of factors within their normal ranges disproportionately results in extreme thrombin generation phenotypes, implying that measurement of a smaller set of factors may be sufficient to identify individuals with aberrant thrombin generation potential despite normal coagulation proteome composition. [ABSTRACT FROM AUTHOR]

An alternative graphical method, called the SSR plot, is proposed for use with a multiple regression model. The new method uses the fact that the sum of squares for regression (SSR) of two explanatory variables can be partitioned into the SSR of one variable and the increment in SSR due to the addition of the second variable. The SSR plot represents each explanatory variable as a vector in a half circle. Our proposed SSR plot explains that the explanatory variables corresponding to the vectors located closer to the horizontal axis have stronger effects on the response variable. Furthermore, for a regression model with two explanatory variables, the magnitude of the angle between two vectors can be used to identify suppression. [ABSTRACT FROM AUTHOR]

Regression diagnostics and lack-of-fit tests mainly focus on linear--linear regression models. When the design points are distributed on the circumference of a circle, difficulties arise as there is no natural starting point or origin. Most classical lack-of-fit tests require an arbitrarily chosen origin, but different choices may result in different conclusions. We propose a graphical diagnostic tool and a closely related lack-of-fit test, which does not require a natural starting point. The method is based on regional residuals which are defined on arcs of the circle. The graphical method formally locates and visualizes subsets of poorly fitting observations on the circle. A data example from the food technology is used to point out the before-mentioned problems with conventional lack-of-fit tests and to illustrate the strength of the methodology based on regional residuals in detecting and localizing departures from the no-effect hypothesis. A small simulation study shows a good performance of the regional residual test in case of both global and local deviations from the null model. Finally, the ideas are extended to the case of more than one predictor variable. [ABSTRACT FROM AUTHOR]

A random effects model using two levels of hierarchical nesting has been applied to the calculation of a likelihood ratio as a solution to the problem of comparison between two sets of replicated multivariate continuous observations where it is unknown whether the sets of measurements shared a common origin. Replicate measurements from a population of such measurements allow the calculation of both within-group and between-group variances/covariances. The within-group distribution has been modelled assuming a Normal distribution, and the between-group distribution has been modelled using a kernel density estimation procedure. A graphical method of estimating the dependency structure among the variables has been used to reduce this highly multivariate problem to several problems of lower dimension. The approach was tested using a database comprising measurements of eight major elements from each of four fragments from each of 200 glass objects and found to perform well compared with previous approaches, achieving a 15.2% false-positive rate, and a 5.5% false-negative rate. The modelling was then applied to two examples of casework in which glass found at the scene of the criminal activity has been compared with that found in association with a suspect. [ABSTRACT FROM AUTHOR]

In digitally controlled dc-dc converters with a single voltage feedback loop, the two quantizers, namely the analog-to-digital (A/D) converter and the digital pulse-width modulator (DPWM), can cause undesirable limit-cycle oscillations. In this paper, static and dynamic models that include the quantization effects are derived and used to explain the origins of limit-cycle oscillations. In the static model, existence of dc solution, which is a necessary no-limit-cycle condition, is examined using a graphical method. Based on the generalized describing function method, the amplitude and offset-dependent gain model of a quantizer is applied to derive the dynamic system model. From the static and dynamic models, no-limit-cycle conditions associated with AID, DPWM and compensator design criteria are derived. The conclusions are illustrated by simulation and experimental examples. [ABSTRACT FROM AUTHOR]

Based on Fick’s diffusion law, mathematical model for specimens with simple shapes such as slab, sphere and cylinder are developed for condensed-solvent debinding process of powder injection molding. A graphical method is introduced to forecast the debinding process using the established model while complicated calculation could be avoided. Experiments are carried out to verify the mathematical model and graphical method, and the results are very close to those calculated from the up-mentioned model and method. [Copyright &y& Elsevier]

Fruits and vegetables have shorter shelf life due to their perishable nature. Tomato, being a nutritionally rich fruit needs to be preserved for a longer period. In this context, this study was designed to dry the tomato slices through microwave–vacuum drying. This process was optimized for moisture ratio and drying rate using response surface methodology (RSM). The process was investigated at different power levels (30, 50, 80, and 100 W), pressure (0, 15, 20, and 25 inHg), and time (0, 4, 6, and 10 min) using Box–Behnken design. Results indicated that color, energy efficiency, and drying characteristics were significantly affected by changing power, vacuum levels, and processing time. Besides, nine mathematical models were applied on experimental data to deeply understand the moisture ratio of tomato slices. Amongst, Midilli model was found best to describe the drying process at 100 W and 25 inHg supported by R2 (0.9989), RMSE (0.001), and X2 (1.34e−4). This study was focused on finding the optimal combinations of power, vacuum pressure, and time for better drying and reduced wastage of the fruit owing to its perishable nature. From all the microwave powers, higher microwave power and vacuum level showed better energy consumption, energy efficiencies, color retention, and rehydration capacity. [ABSTRACT FROM AUTHOR]

Several studies have shown cycles in the vote for political parties in American presidential elections, raising the question of whether cycles are unique to two-party systems. This study extends the investigation of cycles to parliamentary elections in several countries that have multiple political parties: Japan, Germany, Norway, and Canada. Phase-space analysis, a graphical method, is used to show that these countries have a variety of cyclic voting patterns in the distribution of votes among their political parties. Voting cycles may be associated with significant changes in the political party system and with stability of the government. Voting in presidential elections in Alabama is shown to have some characteristics of chaotic change, which is an extreme form of cyclic behavior. The possibility of chaos in voting behavior raises important research issues. [ABSTRACT FROM AUTHOR]

Zvi Griliches was one of the leading econometricians of his generation. His early work involved empirical analyses of the sources of productivity growth in twentieth-century US agriculture, including his dissertation on the diffusion of hybrid corn and his analysis of the long-run growth in fertilizer use by US farmers. In this research Griliches developed theoretical explanations of these phenomena in the form of narratives of rational, profit-seeking people responding to changing circumstances and novel information, and he used these narratives to inform his decisions about what statistical techniques to employ and how to implement them. Narratives served the same purposes for Griliches that mathematical models were coming to serve in the work of his contemporaries, but they made more sense for Griliches, given his belief that he was analyzing transitions between economic equilibria, a process for which economists had not developed useful mathematical models. [ABSTRACT FROM AUTHOR]

The transmission mechanism of artificial flapping-wing drones generally needs low weight and the fewest interconnecting components, making their development challenging. The four-bar Linkage mechanism for flapping actuation has generally been used till now with complex and heavy connecting designs, but our proposed novel perpendicularly organized 3-cylindrical joint mechanism is designed to be unique and lighter weight with smooth functioning performance. The proposed prototype transforms the rotary motion of the motor into a specific angle of flapping movement, where the dimensions and specifications of the design components are proportional to the obtained flapping angle. Power consumption and flapping actuation can be monitored by adjusting the motor's rotational speed to control the individual wing in this mechanism. The proposed mechanism consists of a crank with three slightly slidable cylindrical joints perpendicularly arranged to each other with a specified distance in a well-organized pattern to produce a flapping movement at the other end. In order to examine the kinematic attributes, a mathematical process approach is formulated, and kinematic simulations are performed using SIMSCAPE multibody MATLAB, PYTHON programming and COMPMECH GIM software. The proposed invention's real-time test bench prototype model is designed, tested and analyzed for flapping validation. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Mathematics, Mechanics & Computer Science is the property of Al-Farabi Kazakh National University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper presents the mathematical model for calculating rotary-vane gas refrigerating machine operating cycle main parameters that have an impact on the unit operation, machine control and working processes occurring in it at the specified criteria. The procedure and graphical method for the rotaryvane gas refrigerating machine (RVGRM) are proposed. Parametric study of the main geometric variables and temperature variables on the thermal behavior of the system is analyzed. The model considers polytrope index for the compression and expansion in the chamber. Graphs of the pressure and temperature in the chamber of the angle of rotation of the output shaft are received. The possibility of inclusion in the cycle regenerative heat exchanger is appreciated. The change of the coefficient of performance machine after turning the cycle regenerative heat exchanger is analyzed. It is shown that the installation of a regenerator into the RVGRM cycle results in more than 30% COP increasing. The simulation results show that the proposed model can be used in the process of design and optimization of Stirling gas refrigerating machine. [ABSTRACT FROM AUTHOR]

In this contribution we introduced a novel graphical method to compare protein sequences. By mapping a protein sequence into 3D space based on codons and physicochemical properties of 20 amino acids, we are able to get a unique P -vector from the 3D curve. This approach is consistent with wobble theory of amino acids. We compute the distance between sequences by their P -vectors to measure similarities/dissimilarities among protein sequences. Finally, we use our method to analyze four datasets and get better results compared with previous approaches. [ABSTRACT FROM AUTHOR]

Milled peat must be dried for the production of peat fuel briquettes. The current trend in the creation of drying technologies is the intensification of the dehydration process while obtaining a high-quality final product. An increase in the temperature of the drying agent, above 300 °C, significantly accelerates the reaching of the final moisture content of the peat. In the final stage, it is also accompanied by partial thermal decomposition of the solid phase. Its first stage, which is the decomposition of hemicellulose, contributes to a decrease in weight and an increase in the caloric content of the dry residue. The development of high-temperature drying modes consists of determining the temperature and velocity of the drying agent, wherein the duration of the material reaching the equilibrium moisture content will be minimal and the temperature of the material will not rise above the second-stage decomposition temperature of cellulose. This problem can be solved by the mathematical modeling of the dynamics of peat particles drying in the flow. The article presents a mathematical model of heat and mass transfer, phase transitions, and shrinkage during the dehydration of milled peat particles. The equations of the mathematical model were built based on the differential equation of mass transfer in open deformable systems, which, in the absence of deformations, turns into the known equation of state. A numerical method for implementing a mathematical model has been developed. The adequacy of the mathematical model is confirmed by comparing the results of numerical modeling with known experimental data. [ABSTRACT FROM AUTHOR]

Grid forming (GFM) control strategy has been increasingly used in grid-connected converters to regulate system frequency and mimic the inertia of synchronous generator. However, the description of its power angle dynamics under large disturbances is still lacking up to date, which may pose great challenges to stable operation and economic configuration of grid-connected converters in the future power system. To overcome the aforementioned obstacle, a Krylov–Bogoliubov–Mitropolsky (KBM) asymptotic method with the perturbation theory is presented first in this article to derive an analytical solution for power angle trajectory under large disturbances. Considering that the antiderivative problem is usually unsolvable due to the complicated perturbation function, a tailored integral method is further proposed to address this problem and simplify the final result, which facilitates the KBM asymptotic method to the analysis and calculation of power angle trajectory. As a result, an explicit and accurate time-domain expression is obtained, and it reveals the quantitative relationships between control parameters and dynamic characteristics, which may provide a good potential for system transient stability analysis and GFM converter design. In the end, the effectiveness and accuracy of the proposed method are verified by both simulations and control-hardware-in-loop experiments. [ABSTRACT FROM AUTHOR]

Lossy mode resonance (LMR) is an optical resonance phenomenon developed in the past decade, which has been researched for sensors and filters due to its high sensitivity, low loss, and broad tunable range. As a novel technology, if an analytical mathematical model for some fundamental questions like how to design the resonance wavelength, surrounding sensitivity, resonance width, and resonance depth, it will be guiding significance to its development. Herein, this paper develops a generalized Fabry–Perot resonance theory for LMR, where the oblique incidence, cavity loss, and dispersion of substrate and cavity are comprehensively considered, and the consistency of this model and a more rigorous guided wave optics model have been verified. Then, analytical mathematical models are established and analyzed, and the designing criterion for LMR‐based optical devices is proposed. After intensive reviewing the work of predecessors, the previous experimental results are consistent with the prediction of this model, and this model can also provide some new ideas that have not been researched yet. As an assistant to wave optics theory, this paper provides a second perspective to understand LMR phenomenon, and it is hoped the analytical solutions for LMR can be a guide for designing optical devices. [ABSTRACT FROM AUTHOR]