Search results

The purpose of this paper is to present a methodology for parallel simulation that employs the discrete element method (DEM) and improves the cache performance using Hilbert space filling curves (HSFC).

The methodology is well suited for large-scale engineering simulations and considers modelling restrictions due to memory limitations related to the problem size. An algorithm based on mapping indexes, which does not use excessive additional memory, is adopted to enable the contact search procedure for highly scattered domains. The parallel solution strategy uses the recursive coordinate bisection method in the dynamical load balancing procedure. The proposed memory access control aims to improve the data locality of a dynamic set of particles. The numerical simulations presented here contain up to 7.8 millions of particles, considering a visco-elastic model of contact and a rolling friction assumption.

A real landslide is adopted as reference to evaluate the numerical approach. Three-dimensional simulations are compared in terms of the deposition pattern of the Shum Wan Road landslide. The results show that the methodology permits the simulation of models with a good control of load balancing and memory access. The improvement in cache performance significantly reduces the processing time for large-scale models.

The proposed approach allows the application of DEM in several practical engineering problems of large scale. It also introduces the use of HSFC in the optimization of memory access for DEM simulations.

The purpose of this paper is to present a methodology of hybrid parallelization applied to the discrete element method that combines message-passing interface and OpenMP to improve computational performance. The scheme is based on mapping procedures based on Hilbert space-filling curves (HSFC).

The methodology uses domain decomposition strategies to distribute the computation of large-scale models in a cluster. It also partitions the workload of each subdomain among threads. This additional procedure aims to reach higher computational performance by adjusting the usage of message-passing artefacts and threads. The main objective is to reduce the communication among processes. The work division by threads employs HSFC in order to improve data locality and to avoid related overheads. Numerical simulations presented in this work permit to evaluate the proposed method in terms of parallel performance for models that contain up to 3.2 million particles.

Distinct partitioning algorithms were used in order to evaluate the local decomposition scheme, including the recursive coordinate bisection method and a topological scheme based on METIS. The results show that the hybrid implementations reach better computational performance than those based on message passing only, including a good control of load balancing among threads. Case studies present good scalability and parallel efficiencies.

The proposed approach defines a configurable execution environment for numerical models and introduces a combined scheme that improves data locality and iterative workload balancing.

Optimization under a deterministic approach generally leads to a final design in which the performance may degrade significantly and/or constraints can be violated because of perturbations arising from uncertainties. The purpose of this paper is to obtain a better strategy that would obtain an optimum design which is less sensitive to changes in uncertain parameters. The process of finding these optima is referred to as robust design optimization (RDO), in which improvement of the performance and reduction of its variability are sought, while maintaining the feasibility of the solution. This overall process is very time consuming, requiring a robust tool to conduct this optimum search efficiently.

In this paper, the authors propose an integrated tool to efficiently obtain RDO solutions. The tool encompasses suitable multiobjective optimization (MO) techniques (encompassing: Normal-Boundary Intersection, Normalized Normal-Constraint, weighted sum method and min-max methods), a surrogate model using reduced order method for cheap function evaluations and adequate procedure for uncertainties quantification (Probabilistic Collocation Method).

To illustrate the application of the proposed tool, 2D structural problems are considered. The integrated tool prove to be very effective reducing the computational time by up to five orders of magnitude, when compared to the solutions obtained via classical standard approaches.

The proposed combination of methodologies described in the paper, leads to a very powerful tool for structural optimum designs, considering uncertainty parameters, that can be extended to deal with other class of applications.

This study analyzes the competencies toward sustainability in hotel facilities in order to identify the level of implementation of sustainability practices, as well as individual competencies for sustainability in the hospitality companies.

Interviews and a survey with hotel employees were conducted in two important touristic Brazilian cities, Florianopolis, and Rio de Janeiro, considering the TBL (triple bottom line) dimensions. The data were analyzed with content analysis and descriptive statistics and conjoint analysis.

Preventive competencies in the companies' management were identified. The research also revealed that competencies for sustainability are fairly present in the hospitality context yet, which demonstrates the urgency to discuss the theme in both academic and business practices.

The access to the hotel managers impaired the performing of a robust statistical analysis; the study provided new insights about the topics investigated and generated information for the theoretical framework about competencies for sustainability.

The research results emphasized the need for the hotel industry to invest in sustainable strategies to meet its target audience, but also to raise the level of its staff and reduce costs in the long term, offering benefits to society, the environment, and, to their businesses.

The research socially contributes through promoting discussion on sustainability, which is one of the most challenging and relevant issues for society. Besides, it can assist the diffusion of the competencies for sustainability in the hotel industry, as an attempt to decrease their negative externalities on the environment and primary audiences.

It was identified a distance between practice and the triple bottom line concept, which is linked only to environmental practices. Besides, it was found limited knowledge about the concepts of competencies in the companies.

In this chapter, I aim to present a review on the constitution of the sociology of sport as a subfield in Brazil. To do so, I start with the debate over its history, the current status of this academic area and the factors that led to its development. Additionally, I present the main organizations, funding institutions, and the events that support this field. I briefly identify the main postgraduate programs in the country that enable sociological research in sport, mapping their distribution geographically. Next, I present some introductory works of reference on the sociology of sport in Brazil, as well as discussing some authors that were and are key to the field. I highlight the main topics of interest in Brazilian sociology of sport as well as their methodological models and the main theoretical bases of analysis used by late and early career researchers. In conclusion, I evaluate the comprehension and the representation of sport in society and in the academy, pointing to some future perspectives of development and consolidation of the sociology of sport in Brazil.

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.