Diego P. Ruiz and Antolino Gallego
In this paper we present a new autoregressive (AR) method for bispectrum estimation defined in terms of its third‐moment sequence. The method is based on the segmentation of data…
Abstract
In this paper we present a new autoregressive (AR) method for bispectrum estimation defined in terms of its third‐moment sequence. The method is based on the segmentation of data into coupled records, and can be considered to be a modification of the “third order recursion method”(TOR). Its foundation resides in considering the data of the process at the left and the right of each record (needed for the calculation of third moment sequence) as not null and taking them as the data corresponding to the preceding and succeeding record respectively. Several simulated examples show that this method allows model parameters to be obtained with greater precision, most of all when only few data are available per record. The influence of factors such as number of data and records, model order, and added white and coloured Gaussian noise on the parameters’ estimation is also considered.
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Antolino Gallego and Diego P. Ruiz
This paper deals with bispectrum estimation via autoregressive (AR) modelling of a process contaminated by additive Gaussian noise (white and coloured). Two main contributions are…
Abstract
This paper deals with bispectrum estimation via autoregressive (AR) modelling of a process contaminated by additive Gaussian noise (white and coloured). Two main contributions are provided in this work. First, a comparison between the existing third order recursion (TOR) and the constrained third order mean (CTOM) methods is presented. Basically, the second method is shown to be a smoothing windowed version (i.e. a covariance‐type estimator) of the first one, achieved at the expense of the loss of the recursivity in the AR‐model order. This prior analysis has induced us to develop an alternative scheme to tackle this type of problem, which, while maintaining the main feature of the CTOM method as a covariance type estimator, is a recursive‐in‐order algorithm. This recursivity is obtained carrying out an appropriate minimization procedure of some prediction squared errors also defined here. The paper also compares, by means of simulations, this proposed method and the two existing ones.
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Fernando Angulo-Ruiz, Naveen Donthu, Diego Prior and Josep Rialp-Criado
This study aims to ask whether the funding behaviour of companies is different during a recession. Specifically, the authors study whether firms fund marketing resources and…
Abstract
Purpose
This study aims to ask whether the funding behaviour of companies is different during a recession. Specifically, the authors study whether firms fund marketing resources and capabilities with internal or external financing during a recession and under which conditions of strategic financial flexibility debt might be used to fund marketing resources and capabilities in recessions.
Design/methodology/approach
This study estimates empirical models using a newly merged data set covering 17 years, from 2000 to 2016. The authors merge firms’ marketing and financial information from Advertising Age, the American Customer Satisfaction Index, Compustat and the Centre for Research in Security Prices. The sample includes a panel of 653 firm-years of 67 top corporate advertisers.
Findings
The results indicate that firms take recessions as opportunities to be proactive and invest in short- and long-term marketing capabilities, companies with higher strategic financial flexibility relative to their industry peers tend to rely more on debt to fund short- and long-term marketing capabilities during recessions, firms use internal financing to fund their marketing budgets and short-term marketing capabilities in recessionary and non-recessionary periods and firms use internal financing and signals from past stock returns as mechanisms to fund long-term marketing capabilities.
Research limitations/implications
The findings contribute to the body of knowledge on the antecedents of marketing resources and capabilities. The results extend the pecking order theory to include recessions and provide nuances of the financing drivers of resources and capabilities.
Practical implications
Companies should be proactive during recessions and invest in short- and long-term marketing capabilities. When negotiating marketing budgets with chief financial officers, marketing practitioners could suggest the sources to finance specific marketing resources and capabilities. Based on the results of top corporate advertisers, the authors recommend companies to fund marketing capabilities with internal resources (e.g. cash flows, retained earnings), and if cash is not available, companies need to rely on their superior strategic financial flexibility to access long-term debt and fund investments in marketing capabilities. The authors also recommend companies to fund long-term marketing capabilities by re-allocating investments. As well, signals from past performance are an important source to gain access to capital and fund investments in long-term marketing capabilities.
Originality/value
This study provides a more complete picture of the financial antecedents of marketing resources and capabilities in general and during a recession. The authors provide light on the moderating role of strategic financial flexibility during recessions. This study also clarifies the potential signalling of past performance for funding marketing resources and capabilities.
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This paper gives a bibliographical review of the finite element methods (FEMs) applied to the analysis of ceramics and glass materials. The bibliography at the end of the paper…
Abstract
This paper gives a bibliographical review of the finite element methods (FEMs) applied to the analysis of ceramics and glass materials. The bibliography at the end of the paper contains references to papers, conference proceedings and theses/dissertations on the subject that were published between 1977‐1998. The following topics are included: ceramics – material and mechanical properties in general, ceramic coatings and joining problems, ceramic composites, ferrites, piezoceramics, ceramic tools and machining, material processing simulations, fracture mechanics and damage, applications of ceramic/composites in engineering; glass – material and mechanical properties in general, glass fiber composites, material processing simulations, fracture mechanics and damage, and applications of glasses in engineering.
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Diego F. Grijalva, Mary Lou Ponsetto and Yelitza Pontón
The purpose of this paper is to examine how the expansionary phase of a business cycle driven by an exogenous commodity price shock (oil) affects R&D expenditures among Ecuadorian…
Abstract
Purpose
The purpose of this paper is to examine how the expansionary phase of a business cycle driven by an exogenous commodity price shock (oil) affects R&D expenditures among Ecuadorian firms.
Design/methodology/approach
Using two rounds of the Ecuadorian National Science, Technology and Innovation Activities Survey (ACTI 2012 and 2015) and a data set on gross value added (GVA) by industry, we run a sample correction model applied to a panel data of 1,023 firms from 2009 to 2014.
Findings
In deciding whether to invest in R&D, the higher an industry’s GVA, the lower the predicted probability that firms in that industry would invest. Additionally, R&D investments are not procyclical, and there is marginal evidence that they might actually be countercyclical. These findings are consistent with Schumpeter (1939) and Ouyang (2011) and are likely due to an increased opportunity cost of R&D investment during the oil boom.
Originality/value
In this study, we examine a boom period and not a full business cycle. This boom is driven by an exogenous shock, deviating from much of the current literature, which focuses on endogenously driven business cycles. This paper examines how the oil shock impacted a variety of industries, and not just attractive ones. Additionally, this paper adds to the limited literature around R&D and business cycles in Latin America.
Objetivo
El objetivo de este trabajo es examinar cómo la fase de expansión del ciclo económico, impulsada por un choque exógeno en los precios de un producto básico (petróleo), afecta al gasto en I + D de las empresas ecuatorianas.
Diseño/metodología/aproximación
Usando dos rondas de la Encuesta Nacional de Actividades de Ciencia, Tecnología e Innovación (ACTI 2012 and 2015) y una base de datos del valor añadido bruto (VAB) por industrias, se estima un modelo de corrección de muestra aplicado a un panel de 1,023 empresas de 2009 a 2014.
Resultados
En cuanto a la decisión de invertir o no en I + D, mientras mayor es el VAB de una industria, menor es la probabilidad pronosticada de que las empresas inviertan en I + D. Adicionalmente, la inversión en I + D no es procíclica, y de hecho encontramos evidencia marginal de que muestra un comportamiento contracíclico. Estos resultados son consistentes con Schumpeter (1939) y Ouyang (2011) y se explican posiblemente por un incremento en el costo de oportunidad de invertir en I + D durante la bonanza petrolera.
Originalidad/valor
En nuestro estudio examinamos un periodo de auge, y no un ciclo económico completo. Dicho auge fue ocasionado por un choque exógeno en los precios del petróleo, lo cual diferencia el análisis de gran parte de la literatura actual, enfocada en ciclos económicos endógenos. Este trabajo examina cómo la bonanza petrolera impactó a distintas industrias, y no únicamente a las extractivas. Nuestro estudio contribuye a la escasa literatura existente sobre la relación entre el gasto en I + D y los ciclos económicos en Latinoamérica.
Objetivo
O objetivo deste artigo é examinar como a fase de expansão de um ciclo de negócios impulsionada por um choque exógeno de preços de commodities (petróleo) afeta os gastos com P and D entre as empresas equatorianas.
Design/metodologia/abordagem
Utilizando duas rodadas da Pesquisa Nacional Equatoriana de Atividades de Ciência, Tecnologia e Inovação (ACTI 2012 and 2015) e um conjunto de dados sobre o valor agregado bruto (VAB) por indústria, aplicamos um modelo de correção de amostra aplicado a um painel de 1.023 empresas de 2009 a 2014.
Resultados
Ao decidir investir ou não em P and D, quanto maior o VAB de uma indústria, menor a probabilidade prevista que as empresas dessa indústria investiriam. Além disso, os investimentos em P and D não são pró-cíclicos, e há evidências marginais de que eles podem realmente ser contracíclicos. Essas descobertas são consistentes com Schumpeter (1939) e Ouyang (2011) e são provavelmente devidas a um maior custo de oportunidade de investimento em P and D durante o boom do petróleo.
Originalidade/valor
Em nosso estudo, examinamos um período de expansão e não um ciclo completo de negócios. Esse boom é impulsionado por um choque de petróleo exógeno, diferenciando-se de grande parte da literatura atual, que se concentra em ciclos de negócios impulsionados endogenamente. O artigo examina como o choque do petróleo impactou diversas indústrias, e não apenas as extrativistas. Além disso, nosso trabalho contribui para a escassa literatura em torno de P and D e ciclos de negócios na América Latina.
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Enrique de Diego and Paloma Almodóvar
Strategic agility is a fuzzy concept that has become crucial to cope with environmental uncertainty and instability; hence, more in-depth studies are highly needed. The aim of…
Abstract
Purpose
Strategic agility is a fuzzy concept that has become crucial to cope with environmental uncertainty and instability; hence, more in-depth studies are highly needed. The aim of this paper is to shed light on the still diffuse research area of strategic agility by clarifying its scope and concept, as well as identifying the different topics that have been examined thus far. Finally, the intent of this paper is to show the existing gaps in the literature to provide scholars with a clear roadmap for future research.
Design/methodology/approach
Bibliometric and content analyses are used in this study to review the most impactful papers in strategic agility between 1996 and 2021. Citation and mapping analyses are conducted through SciMAT software, and a dynamic approach is adopted by assessing and discussing the evolution of strategic agility throughout five different periods.
Findings
This study reveals that strategic agility is a research line that has neither gained consensus nor reached maturity and that it is linked to several thematic areas or topics. The study offers a complete understanding of the state of the art of strategic agility over time and underscores its main future research lines.
Originality/value
This study presents a complete map of the strategic agility research thus far by using novel bibliometric techniques. This approach is especially interesting because it allows for identifying the dynamic relationships among themes within the topic over five different periods.
研究目的
策略靈活性是一個模糊概念。這個概念對應付環境的不確定性和不穩定性至為重要, 因此, 我們極須對其作更深入之研究。目前, 對策略靈活性的研究範圍仍很分散。本文擬為這研究範圍提供解說, 方法是透過闡釋策略靈活性的範疇和概念, 及確定至今曾被探討過的課題。最後、本文擬顯示目前文獻中的研究缺口, 以為學者提供一個未來研究的清晰藍圖 。
研究的方法/理念
研究利用文獻計量分析法與內容分析法, 去審視1996年至2021年期間研究策略靈活性最有影響力的文章, 透過SciMAT可視化軟件進行引用文獻及繪圖分析, 亦採用動態方法, 去評估及討論橫跨五個不同時期策略靈活性的演變。
研究結果
研究顯示、策略靈活性為一既無共識, 也未臻成熟的研究線; 研究亦顯示、策略靈活性與多個專題領域及主題相關連。本研究使我們對策略靈活性隨著時間推移的最新理念得到全面的理解, 研究亦強調了策略靈活性未來主要的研究線。
研究的原創性/價值
本研究透過新穎的文獻計量分析法, 提供了一個策略靈活性研究發展至今的完整藍圖。這方法至為有趣, 因其能確定橫跨五個不同時期、在同一課題下各個主題間的動態關係。
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Oscar E Ruiz, Camilo Cortes, Diego A Acosta and Mauricio Aristizabal
Curve fitting from unordered noisy point samples is needed for surface reconstruction in many applications. In the literature, several approaches have been proposed to solve this…
Abstract
Purpose
Curve fitting from unordered noisy point samples is needed for surface reconstruction in many applications. In the literature, several approaches have been proposed to solve this problem. However, previous works lack formal characterization of the curve fitting problem and assessment on the effect of several parameters (i.e. scalars that remain constant in the optimization problem), such as control points number (m), curve degree (b), knot vector composition (U), norm degree (k), and point sample size (r) on the optimized curve reconstruction measured by a penalty function (f). The paper aims to discuss these issues.
Design/methodology/approach
A numerical sensitivity analysis of the effect of m, b, k and r on f and a characterization of the fitting procedure from the mathematical viewpoint are performed. Also, the spectral (frequency) analysis of the derivative of the angle of the fitted curve with respect to u as a means to detect spurious curls and peaks is explored.
Findings
It is more effective to find optimum values for m than k or b in order to obtain good results because the topological faithfulness of the resulting curve strongly depends on m. Furthermore, when an exaggerate number of control points is used the resulting curve presents spurious curls and peaks. The authors were able to detect the presence of such spurious features with spectral analysis. Also, the authors found that the method for curve fitting is robust to significant decimation of the point sample.
Research limitations/implications
The authors have addressed important voids of previous works in this field. The authors determined, among the curve fitting parameters m, b and k, which of them influenced the most the results and how. Also, the authors performed a characterization of the curve fitting problem from the optimization perspective. And finally, the authors devised a method to detect spurious features in the fitting curve.
Practical implications
This paper provides a methodology to select the important tuning parameters in a formal manner.
Originality/value
Up to the best of the knowledge, no previous work has been conducted in the formal mathematical evaluation of the sensitivity of the goodness of the curve fit with respect to different possible tuning parameters (curve degree, number of control points, norm degree, etc.).
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Daniel Mejia, Diego A. Acosta and Oscar Ruiz-Salguero
Mesh Parameterization is central to reverse engineering, tool path planning, etc. This work synthesizes parameterizations with un-constrained borders, overall minimum angle plus…
Abstract
Purpose
Mesh Parameterization is central to reverse engineering, tool path planning, etc. This work synthesizes parameterizations with un-constrained borders, overall minimum angle plus area distortion. This study aims to present an assessment of the sensitivity of the minimized distortion with respect to weighed area and angle distortions.
Design/methodology/approach
A Mesh Parameterization which does not constrain borders is implemented by performing: isometry maps for each triangle to the plane Z = 0; an affine transform within the plane Z = 0 to glue the triangles back together; and a Levenberg–Marquardt minimization algorithm of a nonlinear F penalty function that modifies the parameters of the first two transformations to discourage triangle flips, angle or area distortions. F is a convex weighed combination of area distortion (weight: α with 0 ≤ α ≤ 1) and angle distortion (weight: 1 − α).
Findings
The present study parameterization algorithm has linear complexity [𝒪(n), n = number of mesh vertices]. The sensitivity analysis permits a fine-tuning of the weight parameter which achieves overall bijective parameterizations in the studied cases. No theoretical guarantee is given in this manuscript for the bijectivity. This algorithm has equal or superior performance compared with the ABF, LSCM and ARAP algorithms for the Ball, Cow and Gargoyle data sets. Additional correct results of this algorithm alone are presented for the Foot, Fandisk and Sliced-Glove data sets.
Originality/value
The devised free boundary nonlinear Mesh Parameterization method does not require a valid initial parameterization and produces locally bijective parameterizations in all of our tests. A formal sensitivity analysis shows that the resulting parameterization is more stable, i.e. the UV mapping changes very little when the algorithm tries to preserve angles than when it tries to preserve areas. The algorithm presented in this study belongs to the class that parameterizes meshes with holes. This study presents the results of a complexity analysis comparing the present study algorithm with 12 competing ones.
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Giovanna Gianesini and Antonella Brighi
In this study, we aimed at examining the unique and interactive effects of peer violence in cyberspace on adolescents’ emotion regulation and socioemotional adjustment, as well as…
Abstract
Purpose
In this study, we aimed at examining the unique and interactive effects of peer violence in cyberspace on adolescents’ emotion regulation and socioemotional adjustment, as well as the mediational role of resilience in the link between adolescent’s pathogenic relational experiences and behavioral outcomes. Specifically, we intended to explore emotion differentiation and regulation in reaction to bullying perpetration and victimization and in terms of positive (proud, confident, good) and negative (ashamed, excited, guilty), Passive (sad, embarrassed, humiliated) and Reactive (angry, scared) emotions and how it impacted and predicted positive and negative outcomes.
Methodology/approach
A stratified convenient sample of 494 Italian students aged 13–19 years (M = 15.27, SD = 1.23) was selected to represent all different school types in Italy and the students were administered a self-report questionnaire on school bullying involvement. General Linear Models, ANOVA, and T-tests were employed to explore gender differences, the relationships between variables, and their contribution to the predictive model. A two-step Cluster analysis was used to profile adolescents based on patterns of resilience, health outcomes, and cyberbullying involvement.
Findings
Results showed significant gender differences, with females using internet and Facebook more than males and being more resilient, positive, and prosocial, but also responding to victimization with higher levels of alienation, anger, humiliation, and psychosomatic and emotional symptoms. Males perpetrated peer violence more than females, were less likely to be victimized, and were generally less emotionally impacted by it. Victimization rates (63.7%, n = 296) were higher than perpetration rates (51.7%, n = 233) and bully-victimization was prevalent (47.1%). Victims prevalently experienced passive emotions (sadness, humiliation, embarrassment) while perpetrators experienced negative ones (guilt and shame). Cluster analysis evidenced different pathways and trajectories of resilience and cyberbullying involvement: Resilient victims (RV), Healthy uninvolved (HU), Healthy Bullies (HB), Alienated Bully-Victims (ABV), and Resilient Bully-Victims (RBV). RV, HU, and HB resulted all well-adjusted, despite the different involvement in cyberbullying, and also RBV and despite the double involvement in cyberbullying, ABV were the only maladjusted and at-risk group in our sample characterized by very low Positivity, very low Resilience, and extremely high Alienation.
Research implications
This study proposes a comprehensive, developmental, ecological, relational, and self-regulatory resilience approach to cyberbullying, which represents an innovative and advanced contribution to the literature with significant implication for research and practice. Fully understanding and measuring the emotional impact of cyber peer violence and resilience following cyberbullying victimization and perpetration can help in developing targeted interventions for both victims and bullies. This study highlighted the need for a self-regulatory model of resilience for modulating emotions, arousal, and behaviors across contexts, relationships, and difficulties. It also evidenced that moderate levels of resilience and positivity are sufficient to buffer youth from involvement in cyberbullying and to predict healthy adjustment and less pathological outcomes.
Originality/value
By profiling adolescents based on resilience levels, health outcomes, and cyberbullying involvement, we evidenced five distinct trajectories of risk evaluation for cyberbullying beyond participating roles. Our results confirmed the fundamental importance of assessing resilience and emotion regulatory resources together with peer violence involvement in identifying and targeting adolescents at risk.