Inverse Form Research Articles

Life Expectancy and Retirement Age

The extension of life has exerted more and more pressure on the Chinese pension industry. In order to alleviate this pressure, more and more experts and scholars put forward policy recommendations for postponing retirement. At present, the specific reform scheme of the retirement age in China has not yet been introduced, and there are still some disputes on how to carry out the policy of postponing retirement. However, from the perspective of international experience, some countries or regions adjust retirement age directly or indirectly according to the life expectancy of population. This practice is important reference for our country. Whether China should build the adjustment mechanism of life expectancy and retirement age has very high research value. Under this background, this paper investigates the feasibility of establishing the linkage mechanism of life expectancy and retirement age from a perspective of a social planner through mathematical deduction and theoretical research, and further explores the adjustment formula between them. It hopes that this research can enrich and develop the application of overlapping generations model to the pension problem, and give relevant reference to government departments regarding the issue of postponing retirement. This paper, based on two-period overlapping generations model, introduces the retirement factors, and builds a general equilibrium framework in four aspects of individual behavior, enterprise behavior, government behavior and capital market equilibrium under the assumptions of completely competitive market, full employment and government control of the retirement age. With the optimality principle and the comparative static analysis, we find that when the economy is in a stable state, life expectancy with the maximum social welfare is positively related to the retirement age, manifesting a negative inverse proportion function form. Based on this functional relation, we use the parametric estimation method and assignment simulation to solve the adjustment formula of the life expectancy and retirement age of the population, and put forward an adjustment comparison table between them. According to the calculation results and prediction of life expectancy by China Issues National Plan on Population Development（between 2016 to 2030）, we recommend extending the retirement age to 65 years before 2030. In the end, by testing the model, on the premise of keeping the pension balance, we find that if there is no adjustment mechanism between the life expectancy and retirement age, sudden changes in life expectancy will reduce the pension payment, and can lead to the losses of social welfare. Therefore, based on the findings of this paper, and in the context of the extended life expectancy of Chinese population, we suggest that the governments should consider building the adjustment mechanism of life expectancy and retirement age, and increase the retirement age with the extension of life expectancy.

A dissipation-based method for improving the accuracy of computational fluid dynamics simulations of high level non-Newtonian wastes

This paper investigates a new viscosity model for laminar, transitional, and turbulent pipe flow simulations of a non-Newtonian slurry using the Star-CCM+ software. Herschel-Bulkley (HB) rheology equation was used in its original and modified forms to model the fluid viscosity. The realizable k-ε model was used for modeling of turbulence. It was observed that simulations using the HB model predicted inaccurate profiles of U (mean velocity) and U+ (mean velocity in wall units). Therefore, we developed alternative values of viscosity obtained directly from non-linearity of stress–strain variation (α) in each iteration. The developed method, “Alpha method”, applied changes in places where dissipation rate of turbulent kinetic energy occurred and was designed based on local or global dissipation rate values. Inverse values of α were used to test effects of more viscosity reduction for all flow regimes. In prediction of the mean velocities, significant improvements were obtained through global adjustment of viscosity in inverse form during simulation of the laminar and turbulent flow cases. For the transitional flow, obtaining improvements in prediction of U and U+ from the same model version faced challenges. While the global adjustments in direct form were found significantly effective in improving the prediction of U, they failed to predict the U+ accurately. For this purpose, Local viscosity adjustments were found significantly effective.

Wintertime Local Wind Dynamics from Scanning Doppler Lidar and Air Quality in the Arve River Valley

Air quality issues are frequent in urbanized valleys, particularly in wintertime when a temperature inversion forms and the air within the valley is stably stratified over several days. In addition to pollutant sources, local winds can have a significant impact on the spatial distribution and temporal evolution of pollutant concentrations. They can be very complex and difficult to represent in numerical weather prediction models, particularly under stable conditions. Better knowledge of these local winds from observations is also a prerequisite to improving air quality prediction capability. This paper analyses local winds during the Passy-2015 field experiment that took place in a section of the Arve river valley, near Chamonix–Mont-Blanc. This location is one of the worst places in France regarding air quality. The wind analysis, which is mainly based on scanning Doppler lidar data sampling a persistent temperature inversion episode, reveals features consistent with the higher pollutant concentrations observed in this section of the valley as well as their spatial heterogeneities. In particular, an elevated down-valley jet is observed at night in the northern half of the valley, which, combined with a weak daytime up-valley wind, leads to very poor ventilation of the lowest layers. A northeast–southwest gradient in ventilation is observed on a daily-average, and is consistent with the PM10 heterogeneities observed within the valley.

Growth and population structure of the seabob shrimp Xiphopenaeus kroyeri (Decapoda: Penaeidae) on the continental shelf of Sergipe, Brazil

This study evaluated the population structure, growth and longevity of Xiphopenaeus kroyeri in the State of Sergipe. The obtained data were compared with other populations on a latitudinal scale in order to evaluate whether the latitudinal paradigm applies to this species. Shrimp sampling took place monthly from September 2013 to August 2014, in nine stations distributed at 5, 15 and 30 m depths, using a shrimp fishery boat equipped with a ‘double rig’ net. Sexual maturity was estimated by the logistic function y = a/(1 + b*exp(-cx)), and the sex ratio was analysed with the Chi-square test. The individual growth rate was estimated using the von Bertalanffy model, and the longevity was estimated by the inverse form of this formula. A total of 6418 (3457 females and 2961 males) was analysed. The size at onset of sexual maturity was 12 mm of carapace length (CL) for males and 12.5 mm CL for females. The total sex ratio did not differ from the expected (1:1). Males exhibited higher growth coefficients (k) and smaller asymptotic growth (CC∞ = 28.74 mm, k = 0.0081 day−1) than females (CC∞ = 30.79 mm, k = 0.0058 day−1). The estimated longevity (years) was 1.55 for males and 2.15 for females. No evident latitudinal pattern was observed regarding the size at onset of sexual maturity or the growth parameters for X. kroyeri. The information found, besides contributing to the knowledge about the biology of this shrimp, can also clarify hypotheses presented in relation to the latitudinal paradigm along the Brazilian coast.

Matrices, shortest paths, minimal cuts and Euclidian metric for undirected graphs

In the framework of the algebraic approach to looking into characteristics of undirected graphs, the sequence of their matrix representations has been established. The specifics of the matrices in such a sequence makes it possible at last to make a supposition about the explicit form of the Moore-Penrose pseudo inverse of the incidence matrix of an undirected graph. The rightness of the hypothesis has been confirmed by checking using the conditions of Penrose. The usual minimal cuts and shortest paths are shown as objects which are generated by norms introduced into the vector spaces of the edge and vertex flows. If using the Euclidean norm one gets an advantage in doing analysis and synthesis of graphs in comparison to traditional metrics. The proposed metric can be used to generate the behaviour of intelligent agents.

Interval Estimation of a P(X<sub>1</sub> < X<sub>2</sub>) Model for Variables having General Inverse Exponential Form Distributions with Unknown Parameters

In this article the interval estimation of a P(X₁ < X₂) model is discussed when X₁ and X₂are non-negative independent random variables, having general inverse exponential form distributions with different unknown parameters. Different interval estimators are derived, by applying different approaches. A simulation study is performed to compare the estimators obtained. The comparison is carried out on basis of average length, average coverage, and tail errors. The results are illustrated, using inverse Weibull distribution as an example of the general inverse exponential form distribution.

Топологический метод формирования узловых уравнении в обращенной форме для электроэнергетических систем

The theoretical principles of the topological method for producing the inverse form of nodal voltage equations are described. By transforming the well-known electrical state equations, the exact solution for zero iteration of nodal voltage equations is obtained using the matrix of driving currents distribution coefficients. An analytical investigation was carried out, based on which the topological nature of the nodal current distribution coefficients has been revealed. A topological method for calculating the nodal currents distribution coefficients proceeding from various trees of a complex electric network directed graph is proposed. A program for separating specific trees among the possible graphs of a complex electric network has been developed. A comprehensive program for calculating the current distribution coefficients and setting up the parameters of a steady state operation mode in the MATLAB environment has been elaborated. The proposed procedure makes it possible to significantly reduce the scope of performed activities and allows the nonlinear equations of steady-state operating conditions to be positively solved within a shorter period of time.

Calculations of the complex network’s steady-state modes by brining it to equivalent open

The paper considers the development of the idea of diakoptics as applied to the calculation of the steady-state modes of energy system’s complex electrical networks. The well-known goal of diakoptics is to obtain the equations of state for the dedicated part of the system, the study of which is much simpler than the study of the initial system and can be achieved by improving its steady state equations. Technique for dividing a complex-closed system into a set of uncomplicated subsystems was developed based on the inverse form of nodal equations. Analytic expressions for the intersection circuits obtained based on identical equality of voltage at the nodes of the system division into subsystems are proposed. Using the example of 110kV network calculation, the technique for determining the matrixes of generalized parameters of the dedicated subsystems, the sizes of which depend on the number of their broken link is shown. Analytical determination of the equality condition of the voltage of subsystems intersections nodes, allowed analyzing a complex closed network by bringing it to an equivalent open.

Pure Condition of Both 6R Serial and 3-PRS Parallel Robots Using Grassmann-Cayley Algebra

This research presents Pure Condition approach, which has used in analyzing simultaneously the singularity configuration and the rigidity of mechanism. The study cases analysis is implemented on variable joints orientation of 6R (Revolute) Serial Manipulators (SMs) and variable actuated joints position of 3-PRS (Prismatic-Revolute-Spherical) Parallel Manipulators (PMs) using Grassmann-Cayley Algebra (GCA). In this work we require in Projective Space both Twist System (TS) and Global Wrench System (GWS) respectively for serial and parallel manipulators which represent the Jacobian Matrix (J) in symbolic approach to Plucker coordinate vector of lines and unify framework on static and kinematics respectively. This paper, works, is designed to determine geometrically at symbolic level the vanished points of inverse form of this Jacobian Matrix (J) which called superbracket in GCA. The investigation vary to those reported early by introducing GCA approach on the singularity of serial robot, variable joints orientation and actuated positions on robot manipulators (RMs) to analyze rigidity frame work and singularity configuration which involve simultaneously Pure Condition. And the results also revealed a single singularity condition which contains all particulars cases and three general cases such as the shoulder, elbow and wrist singularity for SMs while double, single and undermined singularities respectively for 3-PRS, 3-PRS and 3-PRS PMs which contain all generals and particulars cases.

New Modeling of Steady-State Modes of Complex Electrical Grids of Power Systems

Classical methods for modeling the steady-state modes of complex electrical networks and systems are based on the application of nonlinear node equations. Nonlinear equations are solved by iterative methods, which are connected by known difficulties. To a certain extent, these difficulties can be weakened by applying topological methods. In this paper, we outline the theoretical foundations for the formation of the inverse form of nodal stress equations based on the topology of electrical networks and systems. A new topological method for calculating the distribution coefficients of node currents is proposed based on all possible trees of a directed graph of a complex electrical network. A complex program for calculating current distribution coefficients and forming steady-state parameters in the MATLAB environment has been developed.

Technical note: A noniterative approach to modelling moist thermodynamics

Abstract. Formulation of noniterative mathematical expressions for moist thermodynamics presents a challenge for both numerical and theoretical modellers. This technical note offers a simple and efficient tool for approximating two common thermodynamic relationships: temperature, T, at a given pressure, P, along a saturated adiabat, T(P, θw), as well as its corresponding inverse form θw(P, T), where θw is wet-bulb potential temperature. Our method allows direct calculation of T(P, θw) and θw(P, T) on a thermodynamic domain bounded by −70 ≤ θw &lt; 40 °C, P &gt; 1 kPa and −100 ≤ T &lt; 40 °C, P &gt; 1 kPa, respectively. The proposed parameterizations offer high accuracy (mean absolute errors of 0.016 and 0.002 °C for T(P, θw) and θw(P, T), respectively) on a notably larger thermodynamic region than previously studied. The paper includes a method summary and a ready-to-use tool to aid atmospheric physicists in their practical applications.

Brain drain and income distribution

In a context in which increased income inequality has raised much concern, and skilled workers move easily across countries, an important question arises: how does the brain drain affect income distribution in the source economy? We address this question and introduce two contributions to the literature on brain drain. First, we present and solve a simple stylized model to study whether and, if so, how the brain drain affects the distribution of income, in a context in which higher education is publicly financed with general taxes. Second, we explore empirically the effect of an increase in skilled emigration on income distribution. A key prediction of our theoretical model is the existence of a non-monotonic relationship between income inequality and emigration of skilled workers. Our empirical data confirm this result, showing a statistically significant inverse U-shaped form.

Evaluation of data-driven models for predicting solar photovoltaics power output

Abstract This research was undertaken to evaluate different inverse models for predicting power output of solar photovoltaic (PV) systems under different practical scenarios. In particular, we have investigated whether PV power output prediction accuracy can be improved if module/cell temperature was measured in addition to climatic variables, and also the extent to which prediction accuracy degrades if solar irradiation is not measured on the plane of array but only on a horizontal surface. We have also investigated the significance of different independent or regressor variables, such as wind velocity and incident angle modifier in predicting PV power output and cell temperature. We found wind velocity and module temperature measurements are too unreliable for use in inverse solar PV models. The inverse regression model forms have been evaluated both in terms of their goodness-of-fit, and their accuracy and robustness in terms of their predictive performance. Given the accuracy of the measurements, expected CV-RMSE of hourly power output prediction over the year varies between 3.2% and 8.6% when only climatic data are used. Depending on what type of measured climatic and PV performance data is available, different scenarios have been identified and the appropriate modeling pathways have been proposed. These models are to be implemented on a controller platform for optimum operational planning of microgrids and integrated energy systems.

Improvements on a non-invasive, parameter-free approach to inverse form finding

Our objective is to determine the optimal undeformed workpiece geometry (material configuration) within forming processes when the prescribed deformed geometry (spatial configuration) is given. For solving the resulting shape optimization problem—also denoted as inverse form finding—we use a novel parameter-free approach, which relocates in each iteration the material nodal positions as design variables. The spatial nodal positions computed by an elasto-plastic finite element (FE) forming simulation are compared with their prescribed values. The objective function expresses a least-squares summation of the differences between the computed and the prescribed nodal positions. Here, a recently developed shape optimization approach (Landkammer and Steinmann in Comput Mech 57(2):169–191, 2016) is investigated with a view to enhance its stability and efficiency. Motivated by nonlinear optimization theory a detailed justification of the algorithm is given. Furthermore, a classification according to shape changing design, fixed and controlled nodal coordinates is introduced. Two examples with large elasto-plastic strains demonstrate that using a superconvergent patch recovery technique instead of a least-squares ( $$L^{2}$$ )-smoothing improves the efficiency. Updating the interior discretization nodes by solving a fictitious elastic problem also reduces the number of required FE iterations and avoids severe mesh distortions. Furthermore, the impact of the inclusion of the second deformation gradient in the Hessian of the Quasi-Newton approach is analyzed. Inverse form finding is a crucial issue in metal forming applications. As a special feature, the approach is designed to be coupled in a non-invasive fashion to arbitrary FE software.

Numerical simulation for inverse extrusion forming of the hole of a rigging joint based on DEFORM

Numerical simulation for inverse extrusion forming of the hole of a rigging joint based on DEFORM

SEBUAH KAJIAN MORFOLOGI GENERATIF DALAM “SATUA BALI TALES FROM BALI”

[Title: A Generative Morphology Study in ‘Satua Bali Tales from Bali'] The diversity and uniqueness of language in the world is an interesting linguistic phenomenon to be studied. Word formation is one of interesting research object, because every language of course has diversity in word formation which is called as morphology process. The theory used in this paper is a theory that is written by experts in the field of morphology. The theory used is the theory of morphology, namely: the theory of generative morphology by Halle (1973), Aronaff (1976), and Scalise (1984). Some examples of words were found in "Satua Bali Tales From Bali". The words were classified into words with prefixes, infix, suffixes and confix.&#x0D; In the data found that there were affixes found in the beginning of the word basic (prefix), inserts on the word (infix), suffix on the word base (suffix) or prefix and suffix that appeared together in the word base (confix). In the data also found the word that experienced nasalization process. In the prefix analysis found the fair form, potential and unnatural forms. In the infix analysis only found the fair form. In the suffix analysis found an unusual inverse form in the data. Unusual (strange) inverse forms can cause problems, because in society, those forms are not commonly used. In the confix analysis there was a reasonable invention. There was also a word that experienced a process of nasalization. For example the form of nepukin "see".

Model-based prognosis using an explicit degradation model and Inverse FORM for uncertainty propagation

In this paper, an analytical method issued from the field of reliability analysis is used for prognosis. The inverse first-order reliability method (Inverse FORM) is an uncertainty propagation method that can be adapted to remaining useful life (RUL) calculation. An extended Kalman filter (EKF) is first applied to estimate the current degradation state of the system, then the Inverse FORM allows to compute the probability density function (pdf) of the RUL. In the proposed Inverse FORM methodology, an analytical or numerical solution to the differential equation that describes the evolution of the system degradation is required to calculate the RUL model. In this work, the method is applied to a Paris fatigue crack growth model, and then compared to filter-based methods such as EKF and particle filter using performance evaluation metrics (precision, accuracy and timeliness). The main advantage of the Inverse FORM is its ability to compute the pdf of the RUL at a lower computational cost.

Flexible Mode Compensation by Inverse Shaper in the Loop with Magnitude Saturated Actuators

An input shaping architecture for vibration suppression of flexible systems controlled with magnitude saturated actuators is considered. It is shown that the distributed-delay shapers with the inverse form in the feedback path have the capability of canceling the undesired vibration caused by saturation limit of actuators. The main idea is to treat the saturation effect as a disturbance on the control input of the actuator which can be canceled by the shapers in the feedback control loop. The inverse form of a recently proposed distributed-delay shaper is utilized to dispose of the undesired vibrations subject to saturation. The theoretical results are compared with an existing solution and verified on a laboratory set-up.

Size-Induced Structural Disorder Enables Ultrahard Oxides

It has been empirically observed that decreasing grain size in polycrystalline materials leads to an increase in hardness following a linear dependence with the inverse square root of the size. This so-called Hall–Petch relationship was originally observed in metals and was attributed to the blocking effect of grain boundaries on dislocation motion. However, the Hall–Petch theory is not tenable for explaining similar phenomena in oxide ceramics, where dislocations are virtually immobile at ambient temperature. In this study, multinuclear (27Al, 25 Mg) magnetic resonance spectroscopy is utilized to demonstrate that a reduction in the grain size of MgAl2O4 spinel nanoceramics induces structural disorder in the form of cation site inversion in the grain boundary region, which leads to an increase in the average bond density and bond strength. The rapid increase in the volume fraction of such structurally disordered and strong grain boundary regions with decreasing grain size of the nanoceramics is responsibl...

Some applications using the connection between q-deformed harmonic oscillator and symmetric and asymmetric potentials

In our previous article, the connections between q-deformed harmonic oscillator and the two types of asymmetric (Morse-like) and symmetric (inverse square cosine form) potentials have been investigated. The use of these relations in an inverse way to investigate the properties of q-deformed harmonic oscillators has been proposed. In this work, we explore the possibility of using this approach to study some real physical systems, such as diatomic molecules, phonon, etc.