Terms Of Multipliers Research Articles

Limit analysis of multi-ring masonry arches: a parametric study on the effects of friction angle, geometry, interlocking, and ring number

The majority of built heritage covering large spans are built with curved masonry components, such as multi-ring arches, to attain greater overall thickness. Their ultimate structural capacity when subjected to external loads is significantly influenced by the various construction techniques utilized. Such structures are made up of independent rings that communicate with one another through interface contacts, and the geometrical features, like size, orientation, and the arrangement of units, play a significant role, as do the mechanical characteristics, like friction. Multi-ring arches subjected to a vertical load at quarter span are assessed utilizing an in-house code implementing the upper bound approach of the limit analysis for masonry structures. The formulation of a script for geometry generation has been given and used for the input to the code. A discrete model has been adopted accounting for a combination of size and disposition of blocks, friction angle, number of rings and the span length are taken into account. Following their combination of impacts in terms of collapse multipliers, which are classified as per respective influencing parameters, each one’s importance was demonstrated by classifying them into two major groups as per unit size. The outcomes showed that all the parameters were key influencing factors in the performance of such structures. Using relatively larger units enhanced the impact of interlocking and provided larger collapse multipliers. While interlocking played a more significant role when span was considered, it together with friction had a larger impact when ring number was varied, such that better interlocking and larger friction values provided higher collapse multipliers.

Turizm Sektörünün Türkiye Ekonomisi için Değerlendirilmesi: Girdi – Çıktı Analizi

Tourism sector is one of the important sectors for the countries in terms of increasing employment opportunities, providing income for the economy and raising the foreign currency earnings. Employing 2002 and 2012 input-output tables, the aim of this study is to assess tourism sector of Turkey with the input-output model. According to the results obtained, sectors related to tourism are slightly above the average among all other sectors in terms of employment multipliers, output multipliers and forward - backward linkage effects. The multipliers and linkage effects of these sectors have generally increased in the year of 2012 compared to 2002. Based on Hirschman categories, although the importance of sectors related to tourism generally increased compared to the year of 2002, these sectors are not in the “key sector” category. Consequently, policies increasing the linkages of the tourism sector with the overall economy should be implemented.

Rotation and sliding collapse mechanisms for in plane masonry pointed arches: statistical parametric assessment

Pointed arches are important architectural elements of both western and eastern historical built heritage. In this paper, the effects that different geometrical (slenderness and sharpness) and mechanical (friction and cohesion) parameters have on the in-plane structural response of masonry pointed arches are investigated through the implementation of an upper bound limit analysis approach capable of representing sliding between rigid blocks. Results, in terms of collapse multipliers are presented and quantitatively analyzed following a systematic statistical approach, whereas collapse mechanisms are qualitatively explored and three different outcomes are found; pure rotation, pure sliding and mixed collapse mechanisms. It is concluded that the capacity of the numerical approach implemented to reproduce sliding between blocks plays a major role in the better understanding of masonry pointed arches structural response.

Statistical Assessment of In-Plane Masonry Panels Using Limit Analysis with Sliding Mechanism

Historical masonry structures have a great interest in civil engineering because they constitute a large part of the world’s building heritage. In this paper, the effects that different geometrical (panel ratio, block ratio, and bond type) and mechanical (friction ratio) parameters have on the in-plane structural response of brick masonry panels are investigated. A discrete modeling approach, based on a limit analysis and capable of reproducing sliding mechanisms, formulation by one of the authors has been adopted, enhanced, and implemented. Results, in terms of collapse multipliers and collapse mechanisms, are presented and analyzed following a systematic statistical approach. Statistically significant effects have been found for each factor considered. Furthermore, the statistical model adopted included nonlinear terms that allowed the identification of whether the effect of one parameter on the response depends on the level of any other parameters. Thus, it was observed that two-way factor interactions played an important role in the in-plane response of masonry panels. The panel ratio-friction ratio two-way factor interaction was the one with a more significant effect.

Optimality conditions for robust weak sharp efficient solutions of nonsmooth uncertain multiobjective optimization problems

In this paper, we investigate an uncertain multiobjective optimization problem involving nonsmooth and nonconvex functions. The notion of a (local/global) robust weak sharp efficient solution is introduced. Then, we establish necessary and sufficient optimality conditions for local and/or the robust weak sharp efficient solutions of the considered problem. These optimality conditions are presented in terms of multipliers and Mordukhovich/limiting subdifferentials of the related functions.

Splitting the Riesz basis condition for systems of dilated functions through Dirichlet series

Inspired by the work of Hedenmalm, Lindqvist and Seip, we consider different properties of dilations systems of a fixed function φ∈L2(0,1). More precisely, we study when the system {φ(nx)}n is a Bessel sequence, a Riesz sequence, or it satisfies the lower frame bound. We are able to characterize these properties in terms of multipliers of the Hardy space H2 of Dirichlet series and, also, in terms of Hardy spaces on the infinite polytorus. We also address the multivariate case.

The potential impact of products seized on the western border of Paraná on the Brazilian economy

AbstractThis paper analyzes the illegal trade practices carried out in the Paraná western border region and its impacts on each federative unit (FU) regarding gross output (GO), taxes, labor income, and employment. An interregional input–output system was used for this analysis. The results show that the negative impact on the national economy, if the police/Federal Revenue had not seized any product, would be twice as large as the amount seized, exceeding one billion reais in the 2017 national GO. Thus, considering the volume seized, cigarettes would have been the product that would harm the Brazilian economy most if the seizures had not occurred, and the state most negatively impacted would be Rio Grande do Sul. However, in terms of production, taxes, and income multipliers, the most harmful products for the Brazilian economy would have been electronic and computer products, and the FU most impacted by the entry of these products would have been São Paulo.

The potential impact of products seized on the western border of Paraná on the Brazilian economy

This paper analyzes the illegal trade practices carried out in the Paraná western border region and its impacts on each federative unit (FU) regarding gross output (GO), taxes, labor income, and employment. An interregional input–output system was used for this analysis. The results show that the negative impact on the national economy, if the police/Federal Revenue had not seized any product, would be twice as large as the amount seized, exceeding one billion reais in the 2017 national GO. Thus, considering the volume seized, cigarettes would have been the product that would harm the Brazilian economy most if the seizures had not occurred, and the state most negatively impacted would be Rio Grande do Sul. However, in terms of production, taxes, and income multipliers, the most harmful products for the Brazilian economy would have been electronic and computer products, and the FU most impacted by the entry of these products would have been São Paulo.

Limit analysis approach for the in-plane collapse of masonry arches

This paper deals with the numerical evaluation of the in-plane collapse behaviour of unreinforced masonry arches and portals characterised by different geometries subjected to several loading conditions and modelled as assemblages of rigid blocks in contact through no-tensional and frictional interfaces. This study has been conducted using a new in-house code, which represents the updated version of the numerical procedure presented in the pioneering work of Baggio and Trovalusci). The minimisation problem corresponding to the upper-bound (or kinematic) approach of limit analysis is written as a linear programming problem solved taking advantages of the algorithms nowadays available. An important feature of the code is the capability to provide information about the sliding collapse of masonry structures, adopting the assumption of dilatancy in the analytic description of the yielding surface, permitting to overcome the classical Heyman's hypothesis, which limited the investigation of collapse to only hinging modes. A key contribution of this study is the comparison of results in terms of collapse multipliers and collapse mechanisms, considering different literature contributes as benchmark references. This research reveals the suitability of approaches based on mathematical programming and the crucial role played by sliding.

Bid Price Controls for Car Rental Network Revenue Management

Car rental network revenue management (RM), despite its prevalence for a long time, has received much less attention in the literature than airline RM does and we aim to fill this gap. The key operational characteristics of car rental services include multi-day length of rentals and mobility of inventories, which requires the car rental booking control to account for the inter-temporal and spatial correlations of demands for capacities across different locations and days. We formulate the car rental network RM problem into an infinite-horizon cyclic stochastic dynamic program. To tackle the curse of dimensionality, we propose a Lagrangian relaxation (LR) approach with product- and time-dependent Lagrangian multipliers to decomposing the network problem into multiple single-station single-day sub-problems, which breaks the inter-temporal and spatial correlations simultaneously. We characterize the structural properties of the decomposed problems in terms of the Lagrangian multipliers and then assemble the optimal value functions of the decomposed problems into an approximate value function. We show that the Lagrangian dual problem is a convex program and its minimum value provides an upper bound on the optimal value functions of the original problem. A subgradient-based algorithm is developed to solve the dual problem and derive an LR-based bid price policy. To increase the scalability of the method, we further propose a simpler LR approach with location- and leadtime-dependent Lagrangian multipliers. Our numerical study indicates that both LR-based bid price policies significantly outperform other commonly used heuristics, and that the second LR approach, though slightly worse than the first one, is much faster. Using a set of real-world booking data, we empirically demonstrate the characteristics of car rental service and perform a case study in which we calibrate the arrival process as a Poisson regression model and show that both LR-based bid price policies indeed outperform other heuristics consistently in both in-sample and out-of-sample tests.

Hadamard–Bergman Convolution Operators

We introduce a convolution form, in terms of integration over the unit disc $$\mathbb {D},$$ for operators on functions f in $$H(\mathbb {D})$$ , which correspond to Taylor expansion multipliers. We demonstrate advantages of the introduced integral representation in the study of mapping properties of such operators. In particular, we prove the Young theorem for Bergman spaces in terms of integrability of the kernel of the convolution. This enables us to refer to the introduced convolutions as Hadamard–Bergman convolution. Another, more important, advantage is the study of mapping properties of a class of such operators in Holder type spaces of holomorphic functions, which in fact is hardly possible when the operator is defined just in terms of multipliers. Moreover, we show that for a class of fractional integral operators such a mapping between Holder spaces is onto. We pay a special attention to explicit integral representation of fractional integration and differentiation.

On optimality conditions for robust weak sharp solution in uncertain optimizations

In this paper, we investigate the robust optimization problem involving nonsmooth and nonconvex real-valued functions. We firstly establish a necessary condition for the local robust weak sharp solution of considered problem under a constraint qualification. These optimality conditions are presented in terms of multipliers and Mordukhovich subdifferentials of the related functions. Then, by employing the robust version of the (KKT) condition, and some appropriate generalized convexity conditions, we also obtain some sufficient conditions for the global robust weak sharp solutions of the problem. In addition, some examples are presented for illustrating or supporting the results.

Robust Optimality and Duality in Multiobjective Optimization Problems under Data Uncertainty

In this paper, we employ advanced techniques of variational analysis and generalized differentiation to examine robust optimality conditions and robust duality for an uncertain nonsmooth multiobjective optimization problem under arbitrary uncertainty nonempty sets. We establish necessary and sufficient optimality conditions for (local) robust (weakly) efficient solutions of the considered problem. Our problem involves nonsmooth real-valued functions and data uncertainty in both the objective and constraint functions, and its necessary and sufficient optimality conditions are exhibited in terms of multipliers and the Mordukhovich or Clarke subdifferentials of the related functions. Moreover, we formulate a dual multiobjective problem to the underlying program and examine robust weak, strong, and converse duality relations between the primal problem and its dual under assumptions of (strictly) generalized convexity.

Optimality conditions for a bilevel optimization problem in terms of KKT multipliers and convexificators

In this paper we investigate a bilevel optimization problem by using the optimistic approach. Under a non smooth generalized Guignard constraint qualification, due the optimal value reformulation, the necessary optimality conditions in terms of convexificators and Karush-Kuhn-Tucker (KKT) multipliers are given.

Study of structural complexity of optimal order digital filters for de-noising ECG signal

Selection and implementation of optimal order digital filter for denoising ECG signal on FPGA, based on Signal to Noise Ratio (SNR), error and accuracy using wavelet toolbox is a tedious task. To overcome this problem, an attempt has been made in MATLAB to obtain a noise-free ECG signal based on SNR and mean square error to select optimal order digital filter. An ECG sample from MIT-BIH arrhythmia database is artificially corrupted by adding noise and is filtered through different low-pass IIR and FIR digital filters. The hardware complexity of optimal order digital filters structure is checked in terms of multipliers, adders and delays in MATLAB and their performance is compared based on the number of basic elements and visual inspections. It is found that the elliptic IIR filter and Kaiser window FIR filter require low-filter order for a given specification and hence, requires less number of basic elements.

Antalya İli Tarıma Dayalı Sanayinin Yapısal Analizi

Bu çalışmada Antalya ili tarıma dayalı sanayi sektörünün Input-Output Analizi ile yapısal ilişkileri incelemiştir. Bu amaçla Antalya ilinde faaliyet gösteren tarıma dayalı sanayi işletmeleri ile anket yapılmıştır. Anketlerden elde edilen veriler yardımıyla endüstriyel işlemler tablosu oluşturulmuştur. Bu tablo üzerinden input-output katsayılar matrisine ulaşılmış ve leontief matrisi işlemleri ile sektörler üzerinde üretim çoğaltanları hesaplanmıştır. Çalışmada tarıma dayalı sanayi sektörleri toplulaştırılarak 9 sektöre indirgenmiştir. Elde edilen sonuçlara göre üretim çoğaltanları açısından en yüksek katkıyı sağlayan sektör bitkisel üretimdir. Bu sektörün Leontief Ters Matrisi sütun toplamları 3,26904 olup bu şu anlama gelmektedir; bitkisel üretim sektöründe 1 birimlik bir üretim artışına karşılık diğer dokuz sektörde yaratacağı üretim artışı 3,26904 kat olacaktır. Bu sektörü 3,07305 katsayı bitkisel yağlar ve 2,736016 ile de ile meyve-sebze işleme sanayi izlemektedir. Şekerli ürünler sanayi alanında 1,767583 katsayı hesaplanmıştır. Bu katsayılarla bu alt sektörlerin önemli katkılar sağladığı söylenebilir. İncelenen sektörlerin tümünde birde üretimin bir birim artırılması halinde ilgili satırdaki sektörün üretiminde ortaya çıkacak üretim artışını veren bir başka çoğaltanda söz konusudur. Buna göre unlu mamuller sektörü katsayısı 2,660875 olup en yüksektir. Bu rakama göre incelenen diğer sekiz sektörün üretimlerini bir birim artırmaları halinde unlu mamuller sanayi sekiz sektöre verdiği girdi düzeyini 2,66 kat artırmak durumunda kalacağı söylenebilir.

A Thermodynamical Theory with Internal Variables Describing Thermal Effects in Viscous Fluids

Abstract In this paper the heat conduction in viscous fluids is described by using the theory of classical irreversible thermodynamics with internal variables. In this theory, the deviation from the local equilibrium is characterized by vectorial internal variables and a generalized entropy current density expressed in terms of so-called current multipliers. Cross effects between heat conduction and viscosity are also considered and some phenomenological generalizations of Fourier’s and Newton’s laws are obtained.

How modes of transport perform differently in the economy of Andalusia

This paper analyses the impact of the different modes of transport in the economy of Andalusia. This assessment makes use of multipliers analysis based on a Social Accounting Matrix (SAM). It has been performed a breakdown of output multipliers as a sum of direct, indirect and induced effects, and the salary and employment multipliers have also been calculated. The starting point is the creation of a SAM from the existing one of year 2010, but disaggregating the sector of transport into their different modes. Thanks to this, we establish the different impact in the economy of each mode of transport, highlighting their different performance. Regarding freight transport, train offers better effects in terms of output multipliers than transport by road. In transport of passengers, the impact of high speed train is more important than air transport, two modes that compete in some routes. The results in this paper are the kind that is of highest interest to policy makers, moreover when large investments are required.

Composition operators on the Schwartz space

We study composition operators on the Schwartz space of rapidly decreasing functions. We prove that such a composition operator is never a compact operator and we obtain necessary or sufficient conditions for the range of the composition operator to be closed. These conditions are expressed in terms of multipliers for the Schwartz class and the closed range property of the corresponding operator considered in the space of smooth functions.

Sufficient conditions for convergence of multiple Fourier series with Jk-lacunary sequence of rectangular partial sums in terms of Weyl multipliers

We obtain sufficient conditions for convergence (almost everywhere) of multiple trigonometric Fourier series of functions $f$ in $L_2$ in terms of Weyl multipliers. We consider the case where rectangular partial sums of Fourier series $S_n(x;f)$ have indices $n=(n_1,\dots,n_N) \in \mathbb Z^N$, $N\ge 3$, in which $k$ $(1\leq k\leq N-2)$ components on the places $\{j_1,\dots,j_k\}=J_k \subset \{1,\dots,N\} = M$ are elements of (single) lacunary sequences (i.e., we consider the, so called, multiple Fourier series with $J_k$-lacunary sequence of partial sums). We prove that for any sample $J_k\subset M$ the Weyl multiplier for convergence of these series has the form $W(\nu)=\prod \limits_{j=1}^{N-k} \log(|\nu_{{\alpha}_j}|+2)$, where $\alpha_j\in M\setminus J_k $, $\nu=(\nu_1,\dots,\nu_N)\in{\mathbb Z}^N$. So, the "one-dimensional" Weyl multiplier -- $\log(|\cdot|+2)$ -- presents in $W(\nu)$ only on the places of "free" (nonlacunary) components of the vector $\nu$. Earlier, in the case where $N-1$ components of the index $n$ are elements of lacunary sequences, convergence almost everywhere for multiple Fourier series was obtained in 1977 by M.Kojima in the classes $L_p$, $p>1$, and by D.K.Sanadze, Sh.V.Kheladze in Orlizc class. Note, that presence of two or more "free" components in the index $n$ (as follows from the results by Ch.Fefferman (1971)) does not guarantee the convergence almost everywhere of $S_n(x;f)$ for $N\geq 3$ even in the class of continuous functions.