The paper describes the conceptual and mathematical background of a tool for modelling and optimising transportation networks. The tool has been created to model resources and…
Abstract
The paper describes the conceptual and mathematical background of a tool for modelling and optimising transportation networks. The tool has been created to model resources and cargo flows in port terminal networks. The concept behind the tool is characterised by three features. Firstly the nodes are non-stationary and can be adapted to accommodate changed requirements in the transportation system. Secondly a high degree of complexity is built into the operational modes of the nodes. Thirdly, the concept incorporates an information network interacting closely with nodes and links. All networks can be optimised employing powerful algorithms and tools from system theory, neural networks and combinatorial graph theory.
Andreas Bausch, Thomas Fritz and Kathrin Boesecke
Our meta-analysis of 92 international samples, with a total sample size of 8,491, demonstrates that firms following internationalization strategies by means of external growth…
Abstract
Our meta-analysis of 92 international samples, with a total sample size of 8,491, demonstrates that firms following internationalization strategies by means of external growth modes can realize a significant positive performance impact on firm performance (r=0.156). This performance effect is significantly stronger than for firms using external growth strategies in their home country (117 samples, with a total sample size of 29,998, r=0.077). Moderating effects are found for the type of international business combination (mergers and acquisitions versus alliance) and the internationalizing firm's region of origin, whereas the relatedness of the firms and the region entered show no moderating impact.
In this paper we consider the complementary questions: in what sense do local dynamics prescribe global spatial patterns and to what extent does a global pattern impose…
Abstract
In this paper we consider the complementary questions: in what sense do local dynamics prescribe global spatial patterns and to what extent does a global pattern impose constraints on local interactions. From the standpoint of results from mathematical system theory, it is argued that a modeling approach starting from observed patterns and passing to local dynamics is vastly to be preferred to proceeding in the opposite direction, the usual approach mimicking the procedure followed in the physical sciences. The paper concludes with a discussion of the role of anticipatory decision making and adaptation in the stabilization of certain properties of dynamical spatial processes.
It is often observed in practice that the essential behavior of mathematical models involving many variables can be captured by a much smaller model involving only a few…
Abstract
It is often observed in practice that the essential behavior of mathematical models involving many variables can be captured by a much smaller model involving only a few variables. Further, the simpler model very often displays oscillatory behavior of some sort, especially when critical problem parameters are varied in certain ranges. This paper attempts to supply arguments from the theory of dynamical systems for why oscillatory behavior is so frequently observed and to show how such behavior emerges as a natural consequence of focusing attention upon so‐called “essential” variables in the process of model simplification. The relationship of model simplification and oscillatory behavior is shown to be inextricably intertwined with the problems of bifurcation and catastrophe in that the oscillations emerge when critical system parameters, i.e. those retained in the simple model, pass through critical regions. The importance of the simplification, oscillation and bifurcation pattern is demonstrated here by consideration of several examples from the environmental, economic and urban areas.
Ram Jiwari, Stefania Tomasiello and Francesco Tornabene
This paper aims to capture the effective behaviour of nonlinear coupled advection-diffusion-reaction systems and develop a new computational scheme based on differential…
Abstract
Purpose
This paper aims to capture the effective behaviour of nonlinear coupled advection-diffusion-reaction systems and develop a new computational scheme based on differential quadrature method.
Design/methodology/approach
The developed scheme converts the coupled system into a system of ordinary differential equations. Finally, the obtained system is solved by a four-stage RK4 scheme.
Findings
The developed scheme helped to capture the different types of patterns of nonlinear time-dependent coupled advection-diffusion-reaction systems such as Brusselator model, Chemo-taxis model and linear model which are similar to the existing patterns of the models.
Originality/value
The originality lies in the fact that the developed scheme is new for coupled advection-diffusion-reaction systems such as Brusselator model, Chemo-taxis model and linear models. Second, the captured pattern is similar to the existing patterns of the models.
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Maria Anna De Rosa, Maria Lippiello and Stefania Tomasiello
The purpose of the present paper is to investigate the nonconservative instability of a single-walled carbon nanotube (SWCNT) with an added mass through nonlocal theories. The…
Abstract
Purpose
The purpose of the present paper is to investigate the nonconservative instability of a single-walled carbon nanotube (SWCNT) with an added mass through nonlocal theories. The governing equations are discretized by means of the differential quadrature (DQ) rules, as introduced by Bellman and Casti. DQ rules have been largely used in engineering and applied sciences. Recently, they were applied to enhance some numerical schemes, such as step-by-step integration schemes and Picard-like numerical schemes.
Design/methodology/approach
In the present paper, the DQ rules are used to investigate the nonconservative instability of a SWCNT through nonlocal theories.
Findings
To show the sensitivity of the SWCNT to the values of added mass and the influence of nonlocal parameter on the fundamental frequencies values, some numerical examples have been performed and discussed. Yet, the effect of the different boundary conditions on the instability behaviour has been investigated. The validity of the present model has been confirmed by comparing some results against the ones available in literature.
Originality/value
Applying the nonlocal elasticity theory, this paper presents a re-formulation of Hamilton’s principle for the free vibration analysis of a uniform Euler–Bernoulli nanobeam. The main purpose of this paper is to investigate the free vibration response of an SWCNT with attached mass and for various values of small scale effects.
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Attempts to address how organizations are responding to the growing complexities of global business, technology, and virtual organizations. Argues that organizations can…
Abstract
Attempts to address how organizations are responding to the growing complexities of global business, technology, and virtual organizations. Argues that organizations can co‐operate and compete at the same time in order to be more effective in the marketplace utilizing a relationship perspective. This is why we have integrated the concepts cooperation and effectiveness, to create the new “co‐opetive” terminology. An ecological collaborative value system (CVS) has been developed. The behaviour of the system is affected by the condition of its components, and the system components are affected by environmental conditions. CVS suggests that customers, suppliers, distributors, competitors, and other organizations are equal partners in the system. Argues that it is imperative for a successful alliance and relationship between the collaborators to communicate and cooperate in an atmosphere of frank debate, trust, interdependence, and mutual positive expectation so that the mutual benefits and interests may be achieved. This mechanism may enable each component of the system to monitor its performance and to adjust its operation to ensure uniform quality of its input‐output. In short, it may allow the system to learn, adapt and evolve.
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Certain elements of Hayek’s work are prominent precursors to the modern field of complex adaptive systems, including his ideas on spontaneous order, his focus on market processes…
Abstract
Certain elements of Hayek’s work are prominent precursors to the modern field of complex adaptive systems, including his ideas on spontaneous order, his focus on market processes, his contrast between designing and gardening, and his own framing of complex systems. Conceptually, he was well ahead of his time, prescient in his formulation of novel ways to think about economies and societies. Technically, the fact that he did not mathematically formalize most of the notions he developed makes his insights hard to incorporate unambiguously into models. However, because so much of his work is divorced from the simplistic models proffered by early mathematical economics, it stands as fertile ground for complex systems researchers today. I suggest that Austrian economists can create a progressive research program by building models of these Hayekian ideas, and thereby gain traction within the economics profession. Instead of mathematical models the suite of techniques and tools known as agent-based computing seems particularly well-suited to addressing traditional Austrian topics like money, business cycles, coordination, market processes, and so on, while staying faithful to the methodological individualism and bottom-up perspective that underpin the entire school of thought.
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This study aims to demonstrate the numerical application of differential quadrature (DQ) methods and show the experimental application of free vibration analysis of fiber-metal…
Abstract
Purpose
This study aims to demonstrate the numerical application of differential quadrature (DQ) methods and show the experimental application of free vibration analysis of fiber-metal laminated composite (FML) plates with various boundary conditions.
Design/methodology/approach
The FMLs are hybrid structures consisting of fiber-reinforced polymer matrix composites such as carbon, glass, aramid and different metal sheets, and are currently widely used in the automobile, aircraft and aerospace industries. Thus, free vibration analysis of these hybrid materials is necessary for the design process. The governing equations of motion are derived based on the classical plate theory. The DQ, generalized DQ (GDQ) and harmonic DQ (HDQ) differential quadrature methods have been used to solve the governing equations of an FML composite plate numerically. The accuracy and convergence of the numerical model have been verified by comparing the results available in the published literature with the results obtained from these methods. Moreover, an experimental procedure has been performed in order to compare the results against those of the numerical methods.
Findings
It is noteworthy that a high degree of similarity and accuracy was observed between the numerical results obtained by the DQ methods and the experimental results. Thus, the present study validates the applicability of the DQ methods for designing the FML composite plates.
Originality/value
In this study, the advantages of the DQ methods have been demonstrated differently from previous studies on the vibration analysis of the FML plates.