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In [10] the first author used Lyapunov functionals and studied the exponential stability of the zero solution of finite delay Volterra Integro-differential equation. In this paper, we use modified version of the Lyapunov functional that were used in [10] to obtain criterion for the stability of the zero solution of the infinite delay nonlinear Volterra integro-differential equation

In this paper a collocation method based on the Bessel-hybrid functions is used for approximation of the solution of linear Fredholm-Volterra integro-differential equations (FVIDEs) under mixed conditions. First, we explain the properties of Bessel-hybrid functions, which are combination of block-pulse functions and Bessel functions of first kind. The method is based upon Bessel-hybrid approximations, so that to obtain the operational matrixes and approximation of functions we use the transfer matrix from Bessel-hybrid functions to Taylor polynomials. The matrix equations correspond to a system of linear algebraic equations with the unknown Bessel-hybrid coefficients. Present results and comparisons demonstrate our estimate have good degree of accuracy.

In recent years, space-borne InSAR (interferometric synthetic aperture radar) techniques have shown their capabilities to provide precise measurements of Earth surface displacements for monitoring natural processes. Landslides threaten human lives and structures, especially in urbanized areas, where the density of elements at risk sensitive to ground movements is high. The methodology described in this paper aims at detecting terrain motions and building deformations at the local scale, by means of satellite radar data combined with in situ validation campaigns. The proposed approach consists of deriving maximum settlement directions of the investigated buildings from displacement data revealed by radar measurements and then in the cross-comparison of these values with background geological data, constructive features and on-field evidence. This validation permits better understanding whether or not the detected movements correspond to visible and effective damages to buildings. The method has been applied to the southwestern sector of Volterra (Tuscany region, Italy), which is a landslide-affected and partially urbanized area, through the use of COSMO-SkyMed satellite images as input data. Moreover, we discuss issues and possible misinterpretations when dealing with PSI (Persistent Scatterer Interferometry) data referring to single manufactures and the consequent difficulty of attributing the motion rate to ground displacements, rather than to structural failures.

In this paper, a Volterra-filter-based control algorithm is developed to generate reference currents for a solar photovoltaic-distribution static compensator (PV-DSTATCOM) system in the distribution network. The developed control is analyzed for being stable under Lyapunov stability criterion; consequently, the error function of the system converges to zero asymptotically. The PV-DSTATCOM system is integrated to the grid to compensate the nonlinear load, while supplying solar PV array active power to the grid. The system is modeled in MATLAB and is executed on a developed prototype in the laboratory, under balanced, unbalanced loading conditions, and variable insolation conditions. Moreover, the harmonic distortion of the grid currents is observed under the IEEE-519 standard. [ABSTRACT FROM AUTHOR]

Un breve studio sulla foggia dell'elmo di tipo Negau, nelle sua foggia vetulonica e volterrana, in base al confronto con alcuni bronzetti; e dalla comparazione di reperti archeologici, nella comprensione della sua funzionalità d'utilizzo bellico.Vengono qui presentati, inoltre alcuni interessanti dati resi dalla ricostruzone sperimentale. [ABSTRACT FROM AUTHOR]

Copyright of Thiasos Monografie is the property of Edizioni Quasar di Severino Tognon s.r.l. 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.)

Soil moisture ( SM ) is a key component of the global energy cycle that regulates all domains of the natural environmental and the agricultural system. In this research, the challenge is to develop a low-cost data-intelligent SM forecasting model using climate dynamics (i.e., the climate indices, atmospheric and hydro-meteorological parameters) as the model inputs. A newly designed, multi-model ensemble committee machine learning approach based on the artificial neural network (ANN-CoM) is developed to forecast monthly upper layer (∼0.2 m from the surface) and the lower layer (∼0.2–1.5 m deep) SM at four agricultural sites in Australia’s Murray-Darling Basin. ANN-CoM model is validated with respect to non-tuned second-order Volterra, M5 model tree, random forest, and an extreme learning machine (ELM) models. To construct the ANN-CoM model, the input variables comprised of the hydro-meteorological data from the Australian Water Availability Project, large-scale climate indices and atmospheric parameters derived from the Interim ERA European Centre for Medium-Range Weather Forecasting ECMWF reanalysis fields leads to a total of 60 potential predictors used for SM forecasting. To reduce the model input data dimensionality for accurate forecasts, the Neighborhood Component Analysis (NCA) based feature selection algorithm for regression purposes ( fsrnca ) is applied to determine the relative feature weights related to the targeted variable. The optimal predictor variables are then screened with an ELM model as the fitness function of the fsrnca algorithm to identify the set of most pertinent model variables. Extensive performance evaluation using statistical score metrics with visual and diagnostic plots show that the ensemble committee based, ANN-CoM model is able to effectively capture the nonlinear dynamics involved in the modeling of monthly upper and lower layer SM levels. Therefore, the ANN-CoM multi-model ensemble-based approach can be considered to be a superior SM forecasting tool, portraying as an amicable, integrated (or ensemble) machine learning stratagem that can be explored for soil moisture modeling and applications in agriculture and other hydro-meteorological phenomena. [ABSTRACT FROM AUTHOR]

In this paper, the operational matrices of integration and the product for the alternative Legendre polynomials (ALPs) are first derived. Then, using these operational matrices and the collocation method, the nonlinear Volterra-Fredholm- Hammerstein integral equations are reduced to a set of nonlinear algebraic equations with unknown ALP coefficients. Some error estimations are provided and the efficiency and accuracy is verified by applying the method to some examples chosen from other literature. [ABSTRACT FROM AUTHOR]

Harmonic balance and Volterra-based analysis methods are well known, but the capabilities of these methods have been limited by significant issues of complexity which either constrain their application to relatively simple cases, or limit the accuracy of analysis in more complex cases. This study briefly summarizes recent results which effectively extend the capabilities of both harmonic balance and Volterra-based analysis by making complex analyses much more feasible. The new capabilities and performance of the two approaches are then evaluated and compared using benchmark case studies of a Duffing oscillator and a nonlinear automotive damper. The results offer new insights and lead to different conclusions on the relative merits of harmonic balance versus Volterra-based analysis relative to prior studies and similar benchmark analyses. [ABSTRACT FROM AUTHOR]

This study presents a multiscale framework for downscaling of the General Circulation Model (GCM) outputs to the mean monthly temperature at regional scale using a wavelet based Second order Voltera (SoV) model. The models are developed using the reanalysis climatic data from the National Centers for Environmental Prediction (NCEP) and are validated using the simulated climatic dataset from the Can CM4 GCM for five locations in the Krishna river basin, India. K-means clustering, based on the multiscale wavelet entropy of the predictors, is used for obtaining the clusters of the input climatic variables. Principal component analysis (PCA) is used to obtain the representative variables from each cluster. These input variables are then used to develop a wavelet based multiscale model using Second order Volterra approach to simulate observed mean monthly temperature for the selected locations in the basin. These models are called W-P-SoV models in this paper. For the purpose of comparison, linear multi-resolution models are developed using Multiple Linear regression (MLR) and are called W-P MLR models. The performance of the models is further compared with other Wavelet-PCA based models coupled with Multiple linear regression models (P-MLR) and Artificial Neural Networks (P-ANN), and, stand-alone MLR and ANN to establish the superiority of the proposed approach. The results indicate that the performance of the wavelet based models is superior in terms of downscaling accuracy when compared with the other models used. [ABSTRACT FROM AUTHOR]

This paper presents a multiple-input multiple-output (MIMO) nonlinear mitigation technique for closely spaced concurrent aggregated carrier systems. The transmitter architecture considers band-limited sources, where the predistorter and signal bandwidth are the same, thus reducing transmitter hardware cost and power consumption. The technique relies on multirate processing and linear filtering and uses the carrier frequencies to isolate the contribution of linear and nonlinear basis functions to the desired bands. This approach can be used with any MIMO model structure. In particular, models are linear in the parameters of low computational complexity. The technique was evaluated using three concurrent carriers of 50 MHz each fed to a Doherty amplifier. The results show significant reduction in the error vector magnitude and improvements for the transmitter efficiency using the proposed compensation technique. [ABSTRACT FROM PUBLISHER]

We consider the system of Volterra integro-dynamic equations

Copyright of Cuadernos de Filología Italiana is the property of Universidad Complutense de Madrid 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.)

In this paper, we consider the ideal Iσ generated by all σ-nowhere dense sets in a topological space. Properties of this ideal and its relations with the Volterra property are explored. We show that Iσ is compatible with the topology for any given topological space, an analogue to the Banach category theorem. Some applications of this result and the Banach category theorem are also given.

This paper presents a comparison of existing and novel behavioral models targeted at the outphasing power amplifier (PA) architecture. A comprehensive comparison of ten modeling strategies is presented in the results. Novel techniques for outphasing PAs, such as vector switched and dual path time series, are also presented for the first time. Investigation of such techniques was driven by the analysis of outphasing operation at minimum output powers, demonstrating the generation of frequency-dependent amplitude and phase deviations, which can be difficult to characterize. The increased robustness was achieved at the cost of additional complexity; for practical implementation, time series coefficient reduction techniques were also evaluated. The results of all modeling approaches are experimentally validated for the wideband operation of an NXP 19-W GaN digital outphasing amplifier module. Considering computational complexity and accuracy for system-level modeling across all presented options, a subset of existing and new models is identified as best suited for modeling outphasing PAs. [ABSTRACT FROM PUBLISHER]

Ionic polymer metal composites (IPMCs) are special smart materials that are biocompatible and can be used in biomedical and industrial applications. Using previous samples of a system output in a model (autoregressive models) is not feasible in dominant applications of IPMCs especially in biomedical applications. In this paper, we present a generalized Volterra-based model to achieve a nonautoregressive, nonparametric, and nonlinear identification of IPMC. The significant superiority of this approach is its capability to nonautoregressive identification of both linear and nonlinear behaviors of IPMC actuators even in large deformation situations. [ABSTRACT FROM AUTHOR]

Over the course of the seventeenth century, the ancient world was the subject of documentary and philological interest for artists and intellectuals which led to the rise of antiquarian science and the classification of types. Two volumes by the German Jesuit Athanasius Kircher - Latium id est and the lost volume Iter etruscum written between the mid-fi fties and the seventies reflected on the new ideas that were developing in those years. Th ese take us on a genuine scholarly journey through Lazio and ancient Etruria, where detailed descriptions of the places, their surviving monuments and their unspoiled natural surroundings build up into an archaeological landscape, the fruit of both imaginary reconstructions as well as personal experience and direct observations. An echo of these seventeenth-century naturalistic ideas can be gleaned from the work of renowned landscape painters such as Salvator Rosa, Nicolas Poussin, Claude Lorrain and Gaspard Dughet who were at one time acolytes in the scholarly circle which the Jesuit belonged to. [ABSTRACT FROM AUTHOR]

In this paper ,we investigate the existence and uniquence solution for homogeneous volterra integral equation of the second kind by using the method which is given by athinson ,A.F. These investigation lead us to the extending of some results of manafov ,M.D.

In this paper we study some different method for solving volterra integral equation with singular kernel of the first kind and expanded by using a method for finding the solution using Gamma function when f(x) is an algebraic function and α known. Also we expand the result in case of f(x) is an algebraic function as a polonomial .

Throughout this paper, we present a method for designing feedback-laws which stabilise nonlinear discrete Volterra systems. Our method is based on a factorisation algorithm which decomposes the original system as a composition of a δ-polynomial and a linear series. [ABSTRACT FROM AUTHOR]

Badlands can be defined as complex and peculiar types of erosional formations that develop in clayey environments and are mainly favoured by lithological and topographic features, as well as by markedly seasonal climate. This work aims at assessing badland susceptibility in Volterra municipality located in Tuscany region (Italy) by means of bivariate statistical analysis implemented in a geographic information system. The Volterra municipality is affected by intense soil erosion processes, including rill and gully erosion usually turned out as badland forms, mostly occurring on Pliocene--Pleistocene clayey sediments. Firstly, an inventory of 234 badland areas was produced on the basis of an available pre-existing database, integrated with the interpretation of aerial photographs and supported by a field survey. Badlands were distinguished in type A and type B, according to different evolutional stage, vegetation presence and consequently different landforms. Then, nine geoenvironmental factors supposed to be predisposing for badland occurrence were chosen and combined with the spatial frequency of badland areas derived from the inventory, through Information Value Statistic approach. The result was a badland susceptibility map that highlights a strong control of lithology, slope gradient and land use in conditioning badland development in the investigated area. The effectiveness of the performed model was demonstrated by a validation test computed through a receiver operating characteristics analysis. The outcomes of this work provide an updated badland database that is useful for soil erosion management and further land-use planning within the Volterra municipality. [ABSTRACT FROM AUTHOR]

An empirical model for field-effect transistor (FET) based power detectors is presented. The electrical model constitutes a Volterra analysis based on a Taylor series expansion of the drain current together with a linear embedding small-signal circuit. It is fully extracted from S-parameters and IV curves. The final result are closed-form expressions for the frequency dependence of the noise equivalent power (NEP) in terms of the FET intrinsic capacitances and parasitic resistances. Excellent model agreement to measured NEP of coplanar access graphene FETs with varying channel dimensions up to 67 GHz is obtained. The influence of gate length on responsivity and NEP is theoretically and experimentally studied. [ABSTRACT FROM PUBLISHER]

Recently, different algorithms for identification of several uncertain nonlinear models, referred to as Volterra-type models, were introduced in the literature. This work deals with the development of a suitable robust model predictive control (MPC) scheme able to cope with the uncertain characterization of those types of models. A discrete-time multivariable algorithm with efficient computational performance is developed. A simulation example based on a multivariable distillation column is introduced to illustrate the behavior of this methodology under the presence of uncertainties and constraints on the manipulated and controlled variables. [ABSTRACT FROM PUBLISHER]

We give an existence theorem for some functional-integral equations which includes many key integral and functional equations that arise in nonlinear analysis and its applications. In particular, we extend the class of characteristic functions appearing in Chandrasekhar's classical integral equation from astrophysics and retain existence of its solutions. Extensive use is made of measures of noncompactness and abstract fixed point theorems such as Darbo's theorem.

In this paper we study the existence and approximation of the periodic solutions for system of nonlinear integro-differential equations of Volterra type by Lebesque integrable function, By using weaker conditions of the function F(t,s,x,x) to be measurable in t and bounded by Lebesque integrable function.

The signal bandwidth requirements for base station radio frequency power amplifiers (PAs) has increased with the advent of multicarrier systems employing carrier aggregation. In this letter, we discuss the design of an integrated bias network for power transistors and discuss its implementation in a high power asymmetric Doherty PA. The designed PA achieves 56 dBm of peak power from 1.805 to 1.88 GHz with 50% efficiency at 8-dB backoff and >200 MHz of video bandwidth (two-tone onset of resonance). Excellent digital pre-distortion (DPD) results are also demonstrated with a 65-MHz wide multicarrier multistandard signal. [ABSTRACT FROM AUTHOR]

Poco es lo que se sabe sobre la estancia de Gaspar Becerra en Roma, que hasta ahora se documentaba gracias a su presencia en las reuniones de la congregación de San Lucas, primero en 1544 y luego en 1550, y a la realización, entre este último año y 1551, de una custodia para la iglesia de Santiago de los Españoles. Ya en diciembre de 1557 el andaluz se encontraba en Burgos, por lo que pasó al menos trece años trabajando en la ciudad eterna. Aportamos aquí el contrato que Gaspar Becerra acordó con Constantino del Castillo para realizar su capilla, hoy destruida, en la iglesia de Santiago de los Españoles, cuya reconstrucción y análisis nos permiten concretar la formación y el estilo del andaluz, así como sus conexiones con el artista piacentino Giulio Mazzoni, quien, como corrobora un documento que aquí presentamos, acabó la capilla empezada por Becerra.

Copyright of Electric Machines & Control / Dianji Yu Kongzhi Xuebao is the property of Electric Machines & Control 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.)

In recent years, space-borne InSAR (interferometric synthetic aperture radar) techniques have shown their capabilities to provide precise measurements of Earth surface displacements for monitoring natural processes. Landslides threaten human lives and structures, especially in urbanized areas, where the density of elements at risk sensitive to ground movements is high. The methodology described in this paper aims at detecting terrain motions and building deformations at the local scale, by means of satellite radar data combined with in situ validation campaigns. The proposed approach consists of deriving maximum settlement directions of the investigated buildings from displacement data revealed by radar measurements and then in the cross-comparison of these values with background geological data, constructive features and on-field evidence. This validation permits better understanding whether or not the detected movements correspond to visible and effective damages to buildings. The method has been applied to the southwestern sector of Volterra (Tuscany region, Italy), which is a landslide-affected and partially urbanized area, through the use of COSMO-SkyMed satellite images as input data. Moreover, we discuss issues and possible misinterpretations when dealing with PSI (Persistent Scatterer Interferometry) data referring to single manufactures and the consequent difficulty of attributing the motion rate to ground displacements, rather than to structural failures. [ABSTRACT FROM AUTHOR]

Bu çalışmada, lazer diyodun (LD) lineerize edilmiş tek mod oran denklemleri harici boşluklu LD'ye göre yeniden düzenlenerek bu denklemler harmonik giriş metoduyla birlikte Volterra serileri kullanılarak çözülmüştür. Harmonik transfer fonksiyonlarının elde edilmesinde Volterra-Wiener seri yaklaşımı kullanılmıştır. Bulunan transfer fonksiyonları kullanılarak çıkıştan-girişe doğru kararlılık analizleri yapılmış olup bu analizlerde Nyquist kararlılık kriteri temel alınmştır. Bu çalışmada, açık sistem transfer fonksiyonu TF = (H1/1- G1) elde edilmiştir. TF transfer foksiyonunun Nyquist eğrisi de çizilerek LD'un akım-denetimli osilatör gibi çalıştığı da gösterilmiştir.

Bu çalışmada, lazer diyodun (LD) lineerize edilmiş tek mod oran denklemleri harici boşluklu LD'ye göre yeniden düzenlenerek bu denklemler harmonik giriş metoduyla birlikte Volterra serileri kullanılarak çözülmüştür. Harmonik transfer fonksiyonlarının elde edilmesinde Volterra-Wiener seri yaklaşımı kullanılmıştır. Bulunan transfer fonksiyonları kullanılarak çıkıştan-girişe doğru kararlılık analizleri yapılmış olup bu analizlerde Nyquist kararlılık kriteri temel alınmştır. Bu çalışmada, açık sistem transfer fonksiyonu TF = (H1/1- G1) elde edilmiştir. TF transfer foksiyonunun Nyquist eğrisi de çizilerek LD'un akım-denetimli osilatör gibi çalıştığı da gösterilmiştir.