Search results

1 – 10 of over 1000
Article
Publication date: 1 February 1992

JAY A. ISSA and RICHARD B. NELSON

A numerical analysis of the micromechanical behaviour of a granular material is described using a new program MASOM based on Cundall's discrete element method. In the…

Abstract

A numerical analysis of the micromechanical behaviour of a granular material is described using a new program MASOM based on Cundall's discrete element method. In the analysis the individual grains which make up the material are taken to be deformable 2D polygons of arbitrary size and shape. Contact forces between the grains are calculated according to Mindlin's solution for frictional contact between elastic bodies. The material in each grain is taken to be linear elastic but limited by the fracture strength of the material. Fracture is permitted along any one of a number of candidate fracture planes if an associated compressive load tending to split the gain reaches a critical level. Fragments of fractured grains are carried until they become too small to track using the explicit time integration algorithm used to advance the solution. The MASOM program is able to consider a number of different classes of elements and different types of contact between the various classes. Thus, in addition to the granular material the program can also model containers and loading devices. The program is used to simulate uniaxial and triaxial compression tests for geological materials. The results are shown to give results for stress‐strain and stress difference versus pressure which are in qualitative agreement with test data. The numerical results reveal a very complex micromechanical behaviour in granular materials, including highly variable and rather unstable load paths and a very inhomogeneous load distribution within a representative sample of the material. A video of the response of a typical frictional material to applied loads shows an interesting localized effect near sample boundaries involving crowding together of grains which cannot be observed using conventional static field plots.

Details

Engineering Computations, vol. 9 no. 2
Type: Research Article
ISSN: 0264-4401

Keywords

Article
Publication date: 1 February 2001

Lee W. McKnight

Contends the Internet is a medium for commerce, marketing, advertising and distribution, as well as invention, entertainment and discussion. Reckons that on the Internet…

1559

Abstract

Contends the Internet is a medium for commerce, marketing, advertising and distribution, as well as invention, entertainment and discussion. Reckons that on the Internet there is only on certainty – when creative destruction reigns it is business as usual. Concludes that succeeding in the global Internet economy is very difficult, and survival is far from assured.

Details

info, vol. 3 no. 1
Type: Research Article
ISSN: 1463-6697

Keywords

Book part
Publication date: 29 August 2018

Paul A. Pautler

The Bureau of Economics in the Federal Trade Commission has a three-part role in the Agency and the strength of its functions changed over time depending on the…

Abstract

The Bureau of Economics in the Federal Trade Commission has a three-part role in the Agency and the strength of its functions changed over time depending on the preferences and ideology of the FTC’s leaders, developments in the field of economics, and the tenor of the times. The over-riding current role is to provide well considered, unbiased economic advice regarding antitrust and consumer protection law enforcement cases to the legal staff and the Commission. The second role, which long ago was primary, is to provide reports on investigations of various industries to the public and public officials. This role was more recently called research or “policy R&D”. A third role is to advocate for competition and markets both domestically and internationally. As a practical matter, the provision of economic advice to the FTC and to the legal staff has required that the economists wear “two hats,” helping the legal staff investigate cases and provide evidence to support law enforcement cases while also providing advice to the legal bureaus and to the Commission on which cases to pursue (thus providing “a second set of eyes” to evaluate cases). There is sometimes a tension in those functions because building a case is not the same as evaluating a case. Economists and the Bureau of Economics have provided such services to the FTC for over 100 years proving that a sub-organization can survive while playing roles that sometimes conflict. Such a life is not, however, always easy or fun.

Details

Healthcare Antitrust, Settlements, and the Federal Trade Commission
Type: Book
ISBN: 978-1-78756-599-9

Keywords

Article
Publication date: 1 March 1974

Frances Neel Cheney

Communications regarding this column should be addressed to Mrs. Cheney, Peabody Library School, Nashville, Tenn. 37203. Mrs. Cheney does not sell the books listed here…

Abstract

Communications regarding this column should be addressed to Mrs. Cheney, Peabody Library School, Nashville, Tenn. 37203. Mrs. Cheney does not sell the books listed here. They are available through normal trade sources. Mrs. Cheney, being a member of the editorial board of Pierian Press, will not review Pierian Press reference books in this column. Descriptions of Pierian Press reference books will be included elsewhere in this publication.

Details

Reference Services Review, vol. 2 no. 3
Type: Research Article
ISSN: 0090-7324

Article
Publication date: 1 March 1974

Tom Schultheiss, Lorraine Hartline, Jean Mandeberg, Pam Petrich and Sue Stern

The following classified, annotated list of titles is intended to provide reference librarians with a current checklist of new reference books, and is designed to…

Abstract

The following classified, annotated list of titles is intended to provide reference librarians with a current checklist of new reference books, and is designed to supplement the RSR review column, “Recent Reference Books,” by Frances Neel Cheney. “Reference Books in Print” includes all additional books received prior to the inclusion deadline established for this issue. Appearance in this column does not preclude a later review in RSR. Publishers are urged to send a copy of all new reference books directly to RSR as soon as published, for immediate listing in “Reference Books in Print.” Reference books with imprints older than two years will not be included (with the exception of current reprints or older books newly acquired for distribution by another publisher). The column shall also occasionally include library science or other library related publications of other than a reference character.

Details

Reference Services Review, vol. 2 no. 3
Type: Research Article
ISSN: 0090-7324

Article
Publication date: 1 February 1998

Geoffrey M. Hodgson

This essay explores evolutionary and competence‐based theories of the firm. Evolutionary theories can be regarded as a subset of a wider class of theories, variously…

3273

Abstract

This essay explores evolutionary and competence‐based theories of the firm. Evolutionary theories can be regarded as a subset of a wider class of theories, variously described as “capabilities”, “resource‐based”, or “competence‐based” theories of the firm. These contrast with a different set of contractarian theories, emanating largely from the work of Coase. It is argued that the contractarian theories of the firm misleadingly assume given individuals thus neglecting processes of individual learning and transformation. Similarly underestimated is importance of technology and the persistence of variety in firm structure and performance. The genesis of the alternative, competence‐based approach is outlined, including the important subset of “evolutionary” approaches of the Nelson‐Winter type. The paper concludes with a discussion of the relevance of the competence‐based approach to strategic management.

Details

Journal of Economic Studies, vol. 25 no. 1
Type: Research Article
ISSN: 0144-3585

Keywords

Article
Publication date: 1 June 2002

Barrie O. Pettman and Richard Dobbins

This issue is a selected bibliography covering the subject of leadership.

22390

Abstract

This issue is a selected bibliography covering the subject of leadership.

Details

Equal Opportunities International, vol. 21 no. 4/5/6
Type: Research Article
ISSN: 0261-0159

Keywords

Abstract

Details

Review of Marketing Research
Type: Book
ISBN: 978-0-85724-723-0

Book part
Publication date: 30 August 2019

Md. Nazmul Ahsan and Jean-Marie Dufour

Statistical inference (estimation and testing) for the stochastic volatility (SV) model Taylor (1982, 1986) is challenging, especially likelihood-based methods which are…

Abstract

Statistical inference (estimation and testing) for the stochastic volatility (SV) model Taylor (1982, 1986) is challenging, especially likelihood-based methods which are difficult to apply due to the presence of latent variables. The existing methods are either computationally costly and/or inefficient. In this paper, we propose computationally simple estimators for the SV model, which are at the same time highly efficient. The proposed class of estimators uses a small number of moment equations derived from an ARMA representation associated with the SV model, along with the possibility of using “winsorization” to improve stability and efficiency. We call these ARMA-SV estimators. Closed-form expressions for ARMA-SV estimators are obtained, and no numerical optimization procedure or choice of initial parameter values is required. The asymptotic distributional theory of the proposed estimators is studied. Due to their computational simplicity, the ARMA-SV estimators allow one to make reliable – even exact – simulation-based inference, through the application of Monte Carlo (MC) test or bootstrap methods. We compare them in a simulation experiment with a wide array of alternative estimation methods, in terms of bias, root mean square error and computation time. In addition to confirming the enormous computational advantage of the proposed estimators, the results show that ARMA-SV estimators match (or exceed) alternative estimators in terms of precision, including the widely used Bayesian estimator. The proposed methods are applied to daily observations on the returns for three major stock prices (Coca-Cola, Walmart, Ford) and the S&P Composite Price Index (2000–2017). The results confirm the presence of stochastic volatility with strong persistence.

Details

Topics in Identification, Limited Dependent Variables, Partial Observability, Experimentation, and Flexible Modeling: Part A
Type: Book
ISBN: 978-1-78973-241-2

Keywords

Book part
Publication date: 13 November 2017

Nohora García

Abstract

Details

Understanding Mattessich and Ijiri: A Study of Accounting Thought
Type: Book
ISBN: 978-1-78714-841-3

1 – 10 of over 1000