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Article
Publication date: 4 May 2010

Jon‐Arild Johannessen

In order to explain a phenomenon/problem, some of the mechanisms which elicit the phenomenon/problem must be clarified, since: “a goal of scientific research is to uncover…

Abstract

Purpose

In order to explain a phenomenon/problem, some of the mechanisms which elicit the phenomenon/problem must be clarified, since: “a goal of scientific research is to uncover reality beneath appearance”. The purpose of this paper is to investigate the following issue: how can social mechanisms be examined from a systemic point of view?

Design/methodology/approach

The paper investigates, at an abstract level, what is meant by social mechanisms in social systems in Part 1. Social mechanisms and various explanation models are investigated in Part 2, using the systemic approach.

Findings

However well‐functioning the models developed, this procedure will not have developed a theory of the phenomenon. For that purpose, explanations at a more basic level than the model is able to disclose, will be necessary. The empirical causal model says something about the strength in the relation between the variables and can be used in practice in order to change certain variables to facilitate the desired change in the system.

Originality/value

The paper usefully shows that, if possible, explanations at a more basic level would be desirable; but not necessary for the application of insights in practical contexts. By this, the paper has stated that a theory can be desirable, but not necessary, in order to develop, e.g. innovative organisations. Models and social mechanisms, on the other hand, are necessary to organise knowledge for the purpose of use in practical contexts.

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Article
Publication date: 12 August 2020

Ngoc Le Chau, Ngoc Thoai Tran and Thanh-Phong Dao

Compliant mechanism has been receiving a great interest in precision engineering. However, analytical methods involving their behavior analysis is still a challenge…

Abstract

Purpose

Compliant mechanism has been receiving a great interest in precision engineering. However, analytical methods involving their behavior analysis is still a challenge because there are unclear kinematic behaviors. Especially, design optimization for compliant mechanisms becomes an important task when the problem is more and more complex. Therefore, the purpose of this study is to design a new hybrid computational method. The hybridized method is an integration of statistics, numerical method, computational intelligence and optimization.

Design/methodology/approach

A tensural bistable compliant mechanism is used to clarify the efficiency of the developed method. A pseudo model of the mechanism is designed and simulations are planned to retrieve the data sets. Main contributions of design variables are analyzed by analysis of variance to initialize several new populations. Next, objective functions are transformed into the desirability, which are inputs of the fuzzy inference system (FIS). The FIS modeling is aimed to initialize a single-combined objective function (SCOF). Subsequently, adaptive neuro-fuzzy inference system is developed to modeling a relation of the main geometrical parameters and the SCOF. Finally, the SCOF is maximized by lightning attachment procedure optimization algorithm to yield a global optimality.

Findings

The results prove that the present method is better than a combination of fuzzy logic and Taguchi. The present method is also superior to other algorithms by conducting non-parameter tests. The proposed computational method is a usefully systematic method that can be applied to compliant mechanisms with complex structures and multiple-constrained optimization problems.

Originality/value

The novelty of this work is to make a new approach by combining statistical techniques, numerical method, computational intelligence and metaheuristic algorithm. The feasibility of the method is capable of solving a multi-objective optimization problem for compliant mechanisms with nonlinear complexity.

Details

Engineering Computations, vol. 38 no. 4
Type: Research Article
ISSN: 0264-4401

Keywords

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Book part
Publication date: 1 November 2007

Irina Farquhar and Alan Sorkin

This study proposes targeted modernization of the Department of Defense (DoD's) Joint Forces Ammunition Logistics information system by implementing the optimized…

Abstract

This study proposes targeted modernization of the Department of Defense (DoD's) Joint Forces Ammunition Logistics information system by implementing the optimized innovative information technology open architecture design and integrating Radio Frequency Identification Device data technologies and real-time optimization and control mechanisms as the critical technology components of the solution. The innovative information technology, which pursues the focused logistics, will be deployed in 36 months at the estimated cost of $568 million in constant dollars. We estimate that the Systems, Applications, Products (SAP)-based enterprise integration solution that the Army currently pursues will cost another $1.5 billion through the year 2014; however, it is unlikely to deliver the intended technical capabilities.

Details

The Value of Innovation: Impact on Health, Life Quality, Safety, and Regulatory Research
Type: Book
ISBN: 978-1-84950-551-2

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Book part
Publication date: 23 September 2005

Hans O. Melberg

This chapter argues that models trying to explain the spread of drug use should not be based on standard epidemiological models developed to describe the spread of…

Abstract

This chapter argues that models trying to explain the spread of drug use should not be based on standard epidemiological models developed to describe the spread of infectious diseases. The main weaknesses of the standard model are the lack of attention to micro-foundations and the inappropriateness of several of its assumptions in the context of drug use. An approach based on mechanisms and social interaction is argued to provide a promising alternative to the standard approach. To illustrate this, a model of the spread of drugs based on two mechanisms has been developed (observational learning and social stigma). Lastly, some of the difficulties in testing and deriving policy implications in these models are discussed.

Details

Substance Use: Individual Behaviour, Social Interactions, Markets and Politics
Type: Book
ISBN: 978-1-84950-361-7

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Article
Publication date: 1 November 2010

F.J.P. Reis, L. Malcher, F.M. Andrade Pires and J.M.A. César de Sá

The purpose of this paper is to perform a numerical assessment of two recently proposed extensions of the Gurson‐Tveegard‐Needleman ductile damage constitutive model under…

Abstract

Purpose

The purpose of this paper is to perform a numerical assessment of two recently proposed extensions of the Gurson‐Tveegard‐Needleman ductile damage constitutive model under low stress triaxiality.

Design/methodology/approach

One of the most widely used ductile damage models is the so‐called Gurson‐Tveegard‐Needleman model, commonly known as GTN model. The GTN model has embedded into its damage formulation the effects of nucleation, growth and coalescence of micro‐voids. However, the GTN model does not include void distortion and inter‐void linking in the damage evolution. To overcome this limitation, some authors have proposed the introduction of different shear mechanisms based on micromechanical grounds or phenomenological assumptions. Two of these constitutive formulations are reviewed in this contribution, numerically implemented within a quasi‐static finite element framework and their results critically appraised.

Findings

Through the analysis of the evolution of internal variables, such as damage and effective plastic strain, obtained by performing a set of numerical tests using a Butterfly specimen, it is possible to conclude that the extended GTN models are in close agreement with experimental evidence.

Research limitations/implications

Even though the results obtained with the modified GTN models have shown improvements, it can also be observed that both shear mechanisms have inherent limitations in the prediction of the location of fracture onset for some specific stress states.

Originality/value

From the results reported, it is possible to identify some shortcomings in the recently proposed extensions of the GTN model and point out the direction of further improvements.

Details

International Journal of Structural Integrity, vol. 1 no. 4
Type: Research Article
ISSN: 1757-9864

Keywords

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Book part
Publication date: 30 January 2013

Gianluca Manzo

In their authoritative literature review, Breen and Jonsson (2005) claim that ‘one of the most significant trends in the study of inequalities in educational attainment in…

Abstract

In their authoritative literature review, Breen and Jonsson (2005) claim that ‘one of the most significant trends in the study of inequalities in educational attainment in the past decade has been the resurgence of rational-choice models focusing on educational decision making’. The starting point of the present contribution is that these models have largely ignored the explanatory relevance of social interactions. To remedy this shortcoming, this paper introduces a micro-founded formal model of the macro-level structure of educational inequality, which frames educational choices as the result of both subjective ability/benefit evaluations and peer-group pressures. As acknowledged by Durlauf (2002, 2006) and Akerlof (1997), however, while the social psychology and ethnographic literature provides abundant empirical evidence of the explanatory relevance of social interactions, statistical evidence on their causal effect is still flawed by identification and selection bias problems. To assess the relative explanatory contribution of the micro-level and network-based mechanisms hypothesised, the paper opts for agent-based computational simulations. In particular, the technique is used to deduce the macro-level consequences of each mechanism (sequentially introduced) and to test these consequences against French aggregate individual-level survey data. The paper's main result is that ability and subjective perceptions of education benefits, no matter how intensely differentiated across agent groups, are not sufficient on their own to generate the actual stratification of educational choices across educational backgrounds existing in France at the beginning of the twenty-first century. By computational counterfactual manipulations, the paper proves that network-based interdependencies among educational choices are instead necessary, and that they contribute, over and above the differentiation of ability and of benefit perceptions, to the genesis of educational stratification by amplifying the segregation of the educational choices that agents make on the basis of purely private ability/benefit calculations.

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Article
Publication date: 22 February 2008

Paul D. Cousins, Benn Lawson and Brian Squire

Close links between buyers and suppliers are increasingly cited as a critical differentiator of high and low performers in global supply chains. While the application of…

Abstract

Purpose

Close links between buyers and suppliers are increasingly cited as a critical differentiator of high and low performers in global supply chains. While the application of performance measures to manage supplier relationships has been well‐identified and encouraged in the literature, comparatively little research exists on the inter‐organizational socialization mechanisms that underlie the flow of learning and information within supply chains. The authors aim to develop a model positing that socialization mechanisms play an important role in mediating the relationship between supplier performance measures and performance outcomes.

Design/methodology/approach

A structural equation model, using a sample of 142 manufacturing and service firms based in the UK, tests this hypothesised model.

Findings

The theoretical framework was supported, with results indicating that socialization mechanisms fully mediate the effects of supplier performance measures (communication and operational‐based) on firm performance.

Practical implications

This study provides additional insights for purchasing managers seeking to improve the management of their strategic supplier relationships. The authors find that monitoring supplier performance is not of itself sufficient, rather, it is the process of socializing the buyer and supplier that is critical to success.

Originality/value

As far as the authors are aware, no previous supply chain research has examined how supplier performance measurement systems, socialization mechanisms, and firm performance are related. The paper makes a significant contribution to this literature embedding an established theoretical construct (socialization) into the supply chain literature.

Details

International Journal of Operations & Production Management, vol. 28 no. 3
Type: Research Article
ISSN: 0144-3577

Keywords

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Article
Publication date: 9 March 2010

Jian‐xiao Zou, Zheng‐qian Zhang and Hong‐bing Xu

According to the high‐reliability requirement and especial structure of triple modular redundancy (TMR) emergent trip multi‐machine system, the purpose of this paper is to…

Abstract

Purpose

According to the high‐reliability requirement and especial structure of triple modular redundancy (TMR) emergent trip multi‐machine system, the purpose of this paper is to introduce a highly effective invalidation detecting mechanism based on heartbeat mechanism.

Design/methodology/approach

The structure of TMR system is designed to be multi‐master and multi‐save. According to the multi‐machine environment, an invalidation detecting mechanism is designed. Considering the advantage and weakness of the traditional PULL and PUSH heartbeat model, the mechanism combines PUSH model with PULL model. To further enhance real‐time ability and reliability of the invalidation detecting mechanism, hierarchy heartbeat monitor and integrating the heartbeat message into data transmission are designed in the mechanism.

Findings

The invalidation detecting mechanism combines PUSH with PULL heartbeat monitor model can enhance reliability and decrease the system misdiagnosis rate greatly. By adapting hierarchy heartbeat mechanism and integrating the heartbeat detecting message into the data transmission, the system communication cost is decreased and the input‐to‐output response time is shortened. The effectiveness and reliability of this mechanism are proved by system field commissioning and MATLAB simulation.

Originality/value

Using a new heartbeat invalidation detecting mechanism, this paper provides a new way of fault diagnosis of TMR multi‐machine system.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 29 no. 2
Type: Research Article
ISSN: 0332-1649

Keywords

Abstract

Details

Integrated Land-Use and Transportation Models
Type: Book
ISBN: 978-0-080-44669-1

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Article
Publication date: 13 January 2020

Yu Liu, Jie Hao, Panli Kang, Zhihua Sha, Fujian Ma, Dapeng Yang and Shengfang Zhang

The purpose of this paper is to establish a rigid–flexible coupling model of wind turbine disc brake to simulate the actual working condition of the wind turbine brake and…

Abstract

Purpose

The purpose of this paper is to establish a rigid–flexible coupling model of wind turbine disc brake to simulate the actual working condition of the wind turbine brake and to study the dynamic characteristics of the compensation mechanism under different friction coefficients and braking force. It provides reference for the structure design and optimization of the compensation mechanism (compensation brake wear) in the wind turbine brake.

Design/methodology/approach

Based on multi-body contact dynamics theory, the rigid‒flexible coupling dynamic model of wind turbine brakes with compensation mechanism is established, in which the contact process of the components in the compensation mechanism and the phenomenon of rotation and return are described dynamically, and the rotation angle of the compensation nut and the axial displacement response of the compensation screw are calculated under different parameters.

Findings

The analysis results show that the braking reliability of the brake compensation mechanism can be effectively improved by increasing the friction coefficient of threads or increasing the friction of push rod contact surface; increasing the braking force can also improve the reliability of brake compensation mechanism, but when the braking force comes over a critical value, the effect of braking force on the reliability of the brake is very small. The braking test verifies the effectiveness of the simulation results.

Originality/value

Analyzing the influence of compensation mechanism on braking reliability in the braking process is of great practical significance for improving the braking efficiency and process safety of wind turbine brake.

Details

Multidiscipline Modeling in Materials and Structures, vol. 16 no. 3
Type: Research Article
ISSN: 1573-6105

Keywords

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