Search results
1 – 7 of 7Ana Camila Ferreira Mamede, José Roberto Camacho, Rui Esteves Araújo and Igor Santos Peretta
The purpose of this paper is to present the Moore-Penrose pseudoinverse (PI) modeling and compare with artificial neural network (ANN) modeling for switched reluctance machine…
Abstract
Purpose
The purpose of this paper is to present the Moore-Penrose pseudoinverse (PI) modeling and compare with artificial neural network (ANN) modeling for switched reluctance machine (SRM) performance.
Design/methodology/approach
In a design of an SRM, there are a number of parameters that are chosen empirically inside a certain interval, therefore, to find an optimal geometry it is necessary to define a good model for SRM. The proposed modeling uses the Moore-Penrose PI for the resolution of linear systems and finite element simulation data. To attest to the quality of PI modeling, a model using ANN is established and the two models are compared with the values determined by simulations of finite elements.
Findings
The proposed PI model showed better accuracy, generalization capacity and lower computational cost than the ANN model.
Originality/value
The proposed approach can be applied to any problem as long as experimental/computational results can be obtained and will deliver the best approximation model to the available data set.
Details
Keywords
Barbara de Lima Voss, David Bernard Carter and Bruno Meirelles Salotti
We present a critical literature review debating Brazilian research on social and environmental accounting (SEA). The aim of this study is to understand the role of politics in…
Abstract
We present a critical literature review debating Brazilian research on social and environmental accounting (SEA). The aim of this study is to understand the role of politics in the construction of hegemonies in SEA research in Brazil. In particular, we examine the role of hegemony in relation to the co-option of SEA literature and sustainability in the Brazilian context by the logic of development for economic growth in emerging economies. The methodological approach adopts a post-structural perspective that reflects Laclau and Mouffe’s discourse theory. The study employs a hermeneutical, rhetorical approach to understand and classify 352 Brazilian research articles on SEA. We employ Brown and Fraser’s (2006) categorizations of SEA literature to help in our analysis: the business case, the stakeholder–accountability approach, and the critical case. We argue that the business case is prominent in Brazilian studies. Second-stage analysis suggests that the major themes under discussion include measurement, consulting, and descriptive approach. We argue that these themes illustrate the degree of influence of the hegemonic politics relevant to emerging economics, as these themes predominantly concern economic growth and a capitalist context. This paper discusses trends and practices in the Brazilian literature on SEA and argues that the focus means that SEA avoids critical debates of the role of capitalist logics in an emerging economy concerning sustainability. We urge the Brazilian academy to understand the implications of its reifying agenda and engage, counter-hegemonically, in a social and political agenda beyond the hegemonic support of a particular set of capitalist interests.
Details
Keywords
Vyacheslav V. Kalashnikov, Roberto Carlos Herrera Maldonado, José-Fernando Camacho-Vallejo and Nataliya I. Kalashnykova
One of the most important problems concerning the toll roads is the setting of an appropriate cost for traveling through private arcs of a transportation network. The purpose of…
Abstract
Purpose
One of the most important problems concerning the toll roads is the setting of an appropriate cost for traveling through private arcs of a transportation network. The purpose of this paper is to consider this problem by stating it as a bilevel programming (BLP) model. At the upper level, one has a public regulator or a private company that manages the toll roads seeking to increase its profits. At the lower level, several companies-users try to satisfy the existing demand for transportation of goods and/or passengers, and simultaneously, to select the routes so as to minimize their travel costs. In other words, what is sought is kind of a balance of costs that bring the highest profit to the regulating company (the upper level) and are still attractive enough to the users (the lower level).
Design/methodology/approach
With the aim of providing a solution to the BLP problem in question, a direct algorithm based on sensitivity analysis (SA) is proposed. In order to make it easier to move (if necessary) from a local maximum of the upper level objective function to another, the well-known “filled function (FF)” method is used.
Findings
The paper proposes and tests two versions of the heuristic algorithm to solve the toll optimization problem (TOP) based upon SA for linear programming (LP) problems. The algorithm makes use of an SA procedure for the LP problem at the lower level, as well as of the “filled” function technicalities in order to reach the global optimum when “jammed” at some local optimum. Numerical experiments with a series of small and medium dimension test problems show the proposed algorithm’s robustness and decent convergence characteristics.
Practical implications
Numerical experiments with a series of small- and medium dimension test problems show the proposed algorithm’s robustness and reasonable convergence characteristics. In particular, while ceding in efficiency to other algorithms when solving small problems, the proposed method wins in the case of medium (higher dimensional) test models. Because of that, one can expect a serious real-life impact on the TOP when the proposed methods and/or their improved versions are developed further to be applicable in practice in the near future.
Originality/value
The proposed algorithms are original and perform well when solving small and medium test numerical problems. The proposed heuristics aim at filling in a gap in a series of numerical approaches to the solution of TOP problem listed in the Introduction. To the authors knowledge, no systematic attempts to apply the SA tools to the toll assigned problem have been recently made. Moreover, the combination of these powerful tools with the “FFs” techniques brings forward some new global optimization ideas. Exactly these features build up the knowledge this specific paper offers in relation to previous relevant works.
Details
Keywords
George Henry Millard and Tim Hundleby
– The purpose of this paper is to look at the origins and development of organized crime in Brazil.
Abstract
Purpose
The purpose of this paper is to look at the origins and development of organized crime in Brazil.
Design/methodology/approach
The authors draw on their experience working in law enforcement for many years in Brazil.
Findings
The paper outlines the major crimes committed by organized crime in Brazil and the structure of the main organization carrying them out.
Research limitations/implications
The research concentrates on São Paolo and further research needs to be done.
Originality/value
This is the first attempt to put the development of organized crime in Brazil into a historical and developmental context.
Details
Keywords
The chapter draws on historical evidence from Central America to test two of the most influential theories of the development of democracy: (1) structural theories derived from…
Abstract
The chapter draws on historical evidence from Central America to test two of the most influential theories of the development of democracy: (1) structural theories derived from the work of Barrington Moore and (2) theories of the “political economy of democratic transitions.” The Central American evidence confirms Moore's theory in regard to the anti-democratic role of landed elites, but not the democratic role of the bourgeoisie. Contrary to some structural theories, the industrial working class was also not important in the development of democracy in Central America. Nor does the Central American evidence fit the political economy of democratic transitions model of negotiated or imposed “transitions from above.” A new model, termed the route to democracy through socialist revolution from below is proposed to account for the Central American evidence and the implications of the model are explored for the development of democracy generally.
Arnaldo Camuffo and Fabrizio Gerli
The purpose of this paper is to identify and empirically validate a repertoire of management behaviors associated with the adoption of lean systems, showing how a subset of such…
Abstract
Purpose
The purpose of this paper is to identify and empirically validate a repertoire of management behaviors associated with the adoption of lean systems, showing how a subset of such behaviors differentiates more advanced lean systems in a specific setting.
Design/methodology/approach
The study applies regression analysis and non-parametric hypothesis testing to an original data set coming from field research of 26 cases of adoption of lean operations practices.
Findings
The study: identifies in the lean literature a repertoire of management behaviors that support lean implementations and complement the adoption of lean practices; provides a way to operationalize them; validates this repertoire of behaviors; and shows that a subset of these behaviors is associated with more advanced lean implementations, suggesting the necessity to adopt a situational approach to lean leadership.
Research limitations/implications
The findings have boundary conditions, defined by the national, industrial, and size context in which the study was conducted.
Practical implications
The study provides practical guidance for lean system implementation suggesting a repertoire of management behaviors within which firms can identify and validate specific, appropriate subsets of behaviors aligned with the company strategy, culture, size, environment, bundle of lean operation practices adopted, and maturity stage of lean adoption.
Originality/value
This is the first study to provide quantitative, non-anecdotal evidence of the relationship between specific management behaviors and the successful implementation of lean operations practices. It offers a novel method to operationalize and measure lean management behaviors.
Details