Exponential Approach Research Articles

Be my (little) partner?!—Universities' role in regional innovation systems when large firms are rare

AbstractStructural differences regarding the presence of large firms are likely to influence the performance of Regional Innovation Systems. Regions lacking large firms to act as brokers of knowledge and coordinators of regional (R&D) collaboration may have to rely on other actors to form internal and external links. We investigate whether, in this case, universities can fulfill the needs of Small‐ and Medium‐sized Enterprises (SMEs) with regard to coordination and knowledge flows. Using a data set of subsidized R&D collaborations, we compare universities' network positions in four model regions in Germany. Applying a Temporal Exponential Random Graph Model approach, we examine link formation and network structure with a focus on university–SME ties and their development over time. Results indicate that SMEs profit from connections to the university in all regions. Nevertheless, universities take more central roles in regions where the economic surrounding does contain fewer large firms as sources for knowledge exchange.

Improved Exponential Approach Method in Determining Optimum Solutions for Transportation Problems

This study describes the transportation methods that regulate and distribute resources that provide products where they are needed to achieve efficient transportation costs. Solve a transportation problem in this thesis using the Improved Exponential Approach method, then using the NWC (Northwest) method to test its optimization. The purpose of this research is to get more optimal results as initial consideration to increase the distribution cost savings in the Bread Company. Costs incurred by the company before the study amounted to Rp.3,218,000. The results of this study found that the application of the transportation method using the Improved Exponential Approach method is effectively used compared to the NWC method which has a comparison of transportation costs of Rp. 2,612,500 and Rp. 2,785,000, Optimization test results obtained from the Improved Exponential Approach method amounted to Rp2,612,500. And the Improved Exponential Approach method used by researchers can be applied to the Gardenia company.

Nonlinear effects in steady radiating waves: An exponential asymptotics approach

An asymptotic study is made of nonlinear effects in steady radiating waves due to moving sources in dispersive media. The focus is on problems where the radiated waves have exponentially small amplitude with respect to a parameter μ≪1, as for instance free-surface waves due to a submerged body in the limit of low Froude number. In such settings, weakly nonlinear effects (controlled by the source strength ɛ) can be as important as linear propagation effects (controlled by μ), and computing the wave response for μ, ɛ≪1 may require exponential (beyond-all-orders) asymptotics. This issue is discussed here using a simple model, namely, the forced Korteweg–de Vries (fKdV) equation where μ is the dispersion and ɛ is the nonlinearity parameter. The forcing term f(x) is assumed to be even and its Fourier transform fˆ(k) to decay for k≫1 like Akαexp(−βk), where A, α and β>0 are free parameters. For this class of forcing profiles, the wave response hinges on beyond-all-orders asymptotics only if α>−1, and nonlinear effects differ fundamentally depending on whether α>0, α=0 or −1<α<0. Furthermore, the sign of the forcing amplitude parameter A is an important controlling factor of the nonlinear wave response. The asymptotic results compare favorably against direct numerical solutions of the fKdV equation for a wide range of μ and ɛ, in contrast to the linear wave response whose validity is rather limited.

A Novel Exponential Approach for Dynamic Event-Triggered Leaderless Consensus of Nonlinear Multi-Agent Systems Over Directed Graphs

A Novel Exponential Approach for Dynamic Event-Triggered Leaderless Consensus of Nonlinear Multi-Agent Systems Over Directed Graphs

Some novel solitary wave solutions to the generalized coupled nonlinear Schrödinger–Korteweg–de Vries equations

In this study the generalized exponential rational function approach is used to extract some new exact solitary wave solutions of the generalized coupled nonlinear Schrödinger–Korteweg–de Vries equations. These coupled equations appear in interactions between short and long dispersive waves which are important in a variety of applied sciences and engineering domains. With the help of the Mathematica package software, the solutions found in this study were verified. We also show graphical representations of the solutions for a better understanding of the coupled equations’ behavior and physical structures.

Calculations of the magnitude of responsivities in pH-, temperature- and ion- responsive hydrogels

Stimuli-responsive hydrogels (SRHs) were prepared by thermal free radical redox polymerization in the aqueous solution of N-isopropyl acrylamide (NIPAAm), acrylamide (AAm) with any weak organic acid (such as propenoic acid, cis-butenedioic acid, crotonic acid, methacrylic acid, methylfumaric acid, itaconic acid, aconitic acid in the presence of N,N′-methylene bisacrylamide. DSC thermograms were taken to find the transition zone parameters of SRHs. Swelling studies were carried out to determine the effects of stimuli such as temperature, pH, and ionic strength on the swelling-shrinkage behavior of SRHs and to calculate the magnitude of the stimuli. A sigmoidal equation was used to calculate the parameters such as transition point, the magnitude of the stimulus, minimum and maximum swelling, the amplitude of the transition zone, etc. of the temperature or pH transition zones of SRHs, while the exponential decay equation was used to calculate the parameters of the swelling-ionic strength relationship of the same gels. With the idea that SRHs can be used as a biomaterial, swelling values of SRHs at the pH values of the body fluids at 37 °C were calculated with the help of these sigmoidal equation parameters. Similarly, swelling values of SRHs in hypertonic, isotonic, and hypotonic saline solutions were determined with the help of these exponential decay equation parameters.In conclusion, calculating the responsivity magnitude with the sigmoidal equation or exponential decay equation approach can be a useful tool for chemists, chemical engineers, bioengineers, biomedicine, biomaterials, polymer, and plastic scientists to find the transition zone parameters of stimuli-responsive hydrogels.

IMPROVED EXPONENTIAL APPROACH METHOD DAN ZERO SUFFIX METHOD DALAM MENENTUKAN SOLUSI OPTIMAL PADA MASALAH TRANSPORTASI

The problem of transportation is a problem of distributing goods from several sources to several destinations with the aim of minimizing shipping costs. Distribution activities in a company sometimes experience problems in transportation problems so that a model is needed to determine the optimal distribution using the transportation model. This study aims to determine the route of distribution of beras putri sejati 25 kg in UD Sinar Jaya Abadi so that optimal expenses can be obtained using improved exponential approach and zero suffix method. Based on the calculation results, both methods produce the same three distribution path. The first distribution channel is from Agen Monang Maning to Toko Mekar Sari and Subur Jaya. The second distribution line from the Agen Gatsu Barat to UD Mas Ayana and Toko Dharma. The third line from agen Gianyar to UD Sinar Wangi, Toko Sari Artha, UD Amertha, and Toko Ayu Mega with optimal distribution costs of Rp 1.575.815.00. The difference or efficiency of the total costs incurred in the distribution before and after optimization by UD Sinar Jaya Abadi Rp 499,190.00 or 24%.

A Survey on Gaps between Mean-Variance Approach and Exponential Growth Rate Approach for Portfolio Optimization

Portfolio optimization can be roughly categorized as the mean-variance approach and the exponential growth rate approach based on different theoretical foundations, trading logics, optimization objectives, and methodologies. The former and the latter are often used in long-term and short-term portfolio optimizations, respectively. Although the mean-variance approach could be applied to short-term portfolio optimization, the performance may not be satisfactory (same with the exponential growth rate approach to the long-term portfolio optimization). This survey mainly explores the gaps between these two approaches, and investigates what common ideas or mechanisms are beneficial. Besides, the evaluating framework of this field and some unsolved problems are also discussed.

Hairy black resonators and the AdS4 superradiant instability

The superradiant instability of Kerr-AdS black holes is studied by numerically solving the full 3+1 dimensional Einstein equations. We find that the superradiant instability results in a two stage process with distinct initial and secondary instabilities. At the end of the secondary instability the geometry oscillates at several distinct fundamental frequencies -- a multi-oscillating black hole. The multi-oscillating black hole is remarkably close to a black resonator, albeit with a bit of gravitational hair. During the hairy black resonator epoch, the evolution of the horizon area is consistent with the exponential approach to a constant. By employing different seed perturbations in the initial Kerr-AdS geometry, we also demonstrate that the black resonator's hair is not unique. In the dual quantum field theory description, rotation invariance is spontaneously broken and the energy density is negative in some regions, signaling an exotic state of matter which does not relax to a stationary configuration.

Hybrid grey exponential smoothing approach for predicting transmission dynamics of the COVID-19 outbreak in Sri Lanka

PurposeThe Coronavirus (COVID-19) is one of the major pandemic diseases caused by a newly discovered virus that has been directly affecting the human respiratory system. Because of the gradually increasing magnitude of the COVID-19 pandemic across the world, it has been sparking emergencies and critical issues in the healthcare systems around the world. However, predicting the exact amount of daily reported new COVID cases is the most serious issue faced by governments around the world today. So, the purpose of this current study is to propose a novel hybrid grey exponential smoothing model (HGESM) to predicting transmission dynamics of the COVID-19 outbreak properly.Design/methodology/approachAs a result of the complications relates to the traditional time series approaches, the proposed HGESM model is well defined to handle exponential data patterns in multidisciplinary systems. The proposed methodology consists of two parts as double exponential smoothing and grey exponential smoothing modeling approach respectively. The empirical analysis of this study was carried out on the basis of the 3rd outbreak of Covid-19 cases in Sri Lanka, from 1st March 2021 to 15th June 2021. Out of the total 90 daily observations, the first 85% of daily confirmed cases were used during the training, and the remaining 15% of the sample.FindingsThe new proposed HGESM is highly accurate (less than 10%) with the lowest root mean square error values in one head forecasting. Moreover, mean absolute deviation accuracy testing results confirmed that the new proposed model has given more significant results than other time-series predictions with the limited samples.Originality/valueThe findings suggested that the new proposed HGESM is more suitable and effective for forecasting time series with the exponential trend in a short-term manner.

The exponential invariant energy quadratization approach for general multi-symplectic Hamiltonian PDEs

Many conservative systems in physical sciences can be described by multi-symplectic Hamiltonian PDEs (MS-HPDEs) admitting three important inherent properties named as multi-symplectic conservation law, local energy conservation law and local momentum conservation law. In this paper, we develop a novel strategy to systematically derive linearly implicit local energy-preserving schemes for general MS-HPDEs, which is named the exponential invariant energy quadratization approach (EIEQ). Such novel strategy is based on the exponential form of non-quadratic terms of the state function that can remove the bounded-from-below restriction, so it is more applicable than the traditional IEQ approach widely employed to construct linearly implicit schemes. Moreover, we provide a completely explicit discretization of the auxiliary variable combined with the nonlinear term, which obtains linearly implicit schemes of the constant coefficient, making their more effective than the IEQ schemes for rapid simulations. We also present the multiple EIEQ approach to improve the applicability of the EIEQ approach for MS-HPDEs with more non-quadratic terms. In addition, when periodic or homogeneous boundary conditions are considered, the proposed schemes are global energy-preserving and can be explicitly solved by using the fast Fourier transform. Finally, ample numerical tests are carried out to demonstrate the computational efficiency, conservation and accuracy of EIEQ schemes.

A Comparison between Brown’s and Holt’s Double Exponential Smoothing for Forecasting Applied Generation Electrical Energies in Kurdistan Region

The process of producing electricity from sources of energy is known as electricity production. Electric also isn't freely accessible in environment, thus it should be "manufactured" (i.e., converting another kinds of energy to electrical energy) by utilities with in electricity industry (transportation, distributing, and so on).Moreover, the objective of this study is to compared of Brown’s as well as Holt’s Double Exponential Smoothing also build a best forecasting time series model among two smoothing model forecasting, as well as focuses on optimizing characteristics to use the golden section technique. This exponential smoothing approach has been one of the time series forecasting methods that would be used to forecast (Generation Electrical) with in Kurdistan area. The issue that arises with this technique is determining the appropriate parameters to reduce predict inaccuracy. In addition, Data used in this paper are (Generation Electrical) in Kurdistan region for (132) months from 2010 to 2020. The study revealed that such data is trending modeled, indicating that a double exponential smoothing (DES) approach from Brown &amp; Holt can be used with the (Stratigraphic &amp; Minitab) software. There are the same results but the Result of analysis more depend on the R-program. The difference among the forecast findings acquired with optimum parameters as well as the assaying data was utilized to assess the feasibility of the forecast by completing normality and randomness tests. Ultimately, the outcomes of parameterization show that the optimal value of α that in DES Brown is (0.22) as well as the optimal MAPE is 9.23616 percent, whereas in DES Holt the optimal is (0.95) as well as the optimal β is (0.05) via the optimal MAPE of 8.08586 percent. This MAPE of a DES Brown technique is greater than the MAPE of a DES Holt approach. Feasibility experiments revealed that both approaches are capable of predicting. Depending on the value of MAPE as well as evaluation process, DES Holt's was recognized as the main prediction model.

An improved exponential metric space approach for C‐mean clustering analysing

AbstractIn this article, we present two resilient algorithms, the improved alternative hard c‐means (IAHCM) and the improved alternative fuzzy c‐means (IAFCM). We implement the Gaussian distance‐dependent function proposed by Zhang and Chen (D.‐Q. Zhang and Chen, 2004). In some cases, Zhang and Chen's metric distance does not account for the clustering centroid effect predicted by the large value. R* is employed in IAHCM and IAFCM to discover robust results while minimizing its sensitivity. Experiments are conducted using two‐and three‐dimensional data, including Diamond and Iris real‐world data. The results are based on demonstrating the robust simplicity and applicability of the offered algorithms. Similarly, computational complexity is assessed.

Analytical formalism for calculations of parameters needed for quantitative analysis by X-ray photoelectron spectroscopy

Analytical formalism for calculations of parameters needed for quantitative analysis by X-ray photoelectron spectroscopy

A Modelling of Tunnelling Current through a Trapezoidal Potential Barrier by Using Exponential Wavefunction Approach

A tunnelling current through a trapezoidal barrier potential has been modelled. The transmittance is determined using the exponential wavefunction approach method. Furthermore, the transmittance is used to calculate the tunnelling current density by applying the Gauss-Laguerre quadrature method. The simulation results show the increasing bias voltage causes the raising tunnelling current, and an increase of temperature is proportional to the tunnelling current.

A Modelling of Tunnelling Current through a Trapezoidal Potential Barrier by Using Exponential Wavefunction Approach

A tunnelling current through a trapezoidal barrier potential has been modelled. The transmittance is determined using the exponential wavefunction approach method. Furthermore, the transmittance is used to calculate the tunnelling current density by applying the Gauss-Laguerre quadrature method. The simulation results show the increasing bias voltage causes the raising tunnelling current, and an increase of temperature is proportional to the tunnelling current.

Estimating the long-term strength and time-to-failure of brittle rocks from laboratory testing

The long-term strength and time-to-failure of brittle rocks has become increasingly important with the increased interest in the storage of used nuclear fuel in deep geological repositories . This paper critically reviews and analyzes the currently available time-to-failure data for various brittle rock types. The current best approach on estimating time-to-failure of rock samples at the lab scale under a constant stress is using semi-log data based on the driving stress ratio and the logarithm of time. In most studies, the applied driving stress ratio is calculated based on the average strength of the rock, however, sample strength can vary up to 15%. Therefore, it is proposed that the crack-initiation stress threshold for each sample be used to calculate sample specific ultimate strengths based on relationships determined in literature. It is proposed that if a sample fails during a long-term strength test within the first 1–10 s, the applied stress for that test can be assumed equivalent to the ultimate strength. Additionally, a modified exponential function with a horizontal asymptote at the crack-initiation threshold is explored as an alternative to the typical log-linear approach. The exponential approach is non-linear in semi-log space and does not require an arbitrary cut-off for time-to-failure at the static fatigue limit of the rock as is the case of the semi-log approach. Ultimately, it is shown that although the exponential function does usually provide a better overall fit to data at relatively short times (<1,000,000 s), there is little evidence to justify the asymptotic behaviour in the longer term. Common practice has been to present the driving stress ratio as a function of time-to-failure, however, in theory these axes should be reversed as the variable of interest to the reader is the time-to-failure based on in-situ stresses. The consequence of plot orientation and subsequent error calculation are explored. The goal of this paper is to provide users and researchers with a reliable methodology to predict time-to-failure of brittle rocks both at the lab and excavation scale as well as a basis for incorporating explicit time-to-failure calculations into a continuum numerical model.

Study on improved droop control strategy of MMC-MTDC system based on novel sliding mode control

In view of the strong coupling, nonlinearity and uncertainty of HVDC system, and the poor consistency when the MMC control policy adopts the traditional PI double closed-loop control, an improved droop control policy with the novel sliding pattern controlling is given herein. The controller brings to the dual closed loop control structure, the internal loop takes current error in the dq axis as the sliding mode surface. A sliding mode controller with the novel exponential approach law is designed, which improves the convergence speed of the traditional exponential approach law and eliminates the chattering phenomena. Then the consistency of the system is identified by Lyapunov method. The outer-loop adopts a modified sag control policy. After comparing with the voltage reference value, the droop factor is proposed. Finally, an emulation model including MMC-MTDC with four terminal is constructed on the PSCAD/EMTDC, which is emulated and validated under stable and transient conditions. The consequences reveal that the given control policy not only has a good convergence effect, but also improves the kinematic respond speed. It can also reduce the direct current voltage deviation, and enhances the stability and reliability of the system.

Numerical strategies for variational updates in large strain inelasticity with incompressibility constraint

AbstractIn finite deformation inelasticity, one often has to deal with the incompressibility constraint. In the past, this was dealt with using, for example, an exponential mapping approach, which yields exact volume preservation in plastic deformations. In this article however, the special‐linear update approach by Hurtado et al. The special‐linear update: An application of differential manifold theory to the update of isochoric plasticity flow rules, Int J Numer Methods Eng. 2014;97(4):298‐312, which utilizes a projection method to fulfill the incompressibility constraint is used. The model is applied to isotropic plasticity by a novel approximation of the logarithm and treats kinematic hardening without losing the symmetry of the internal variables. The model results are compared to models utilizing an exponential mapping approach in numerical experiments.

High-order time-accurate, efficient, and structure-preserving numerical methods for the conservative Swift–Hohenberg model

In this study, we develop high-order time-accurate, efficient, and energy stable schemes for solving the conservative Swift–Hohenberg equation that can be used to describe the L2-gradient flow based phase-field crystal dynamics. By adopting a modified exponential scalar auxiliary variable approach, we first transform the original equations into an expanded system. Based on the expanded system, the first-, second-, and third-order time-accurate schemes are constructed using the backward Euler formula, second-order backward difference formula (BDF2), and third-order backward difference formula (BDF3), respectively. The energy dissipation law can be easily proved with respect to a modified energy. In each time step, the local variable is updated by solving one elliptic type equation and the non-local variables are explicitly computed. The whole algorithm is totally decoupled and easy to implement. Extensive numerical experiments in two- and three-dimensional spaces are performed to show the accuracy, energy stability, and practicability of the proposed schemes.