Search results for "Simulation."

Tackling wicked issues in performance management and governance of health prevention: an empirical analysis of vaccination strategies in Italy

Performance management (PM) in the public sector is a research stream that grasped much of the attention of public administration and management scholars in the last decade (Bouckaert & Halligan, 2007; Hall, 2017; Douglas & Ansell, 2020). This is mainly related to the ever-evolving context in which PM regimes apply. Our society and its current challenges are indeed growing in complexity so that these last have been defined by modern literature as “wicked” (Rittel & Weber, 1973; Head & Alford, 2015). Wicked does not mean “evil” but it refers to the impossibility to share an understanding of societal problems and their definition. According to Head & Alford (2015),“wickedn…

Analyzing Business Dynamics of Ride-Hailing Services: A DPM Approach Applied to Uber Inc.

2018

Purpose – The purpose of this paper is to explore business dynamics of a rising ride-hailing service industry through case study and foster understanding of hypothetical feedback effects within the broader system. Design/methodology/approach – The research adopts the dynamic performance management framework with simulation-based methodology for developing a dynamic case interpretation of specific type of business complexity. Findings – Scenario analysis shows that changes in the commission percentage for drivers, and cutting prices for customers (car hailers) by competitors have significant impacts on the car hailing industry. Research limitations – The findings of our analysis are limited …

Generalising Theories Explaining the Different Modes of SME Development and the Associated Growth Trajectories

2010

Previous research has identified two forms of “abnormal” growth – styled as business dwarfism and gigantism - which can both lead to missed opportunities for owners/entrepreneurs and local economies, and even to business crisis and collapse. It has also shown that stunted and inflated growth phenomena, rather than being characterised by completely different rules and rationales, are closely related and that certain fundamental structures and processes underpin both those forms of ab-normal company growth behaviour. This paper reports an examination of a further SME phenomenon – what we have chosen to call "micro-giants". These are companies that would be categorised as rela-tively small fir…

A Physiological Approach to Analysing SME Growth Patterns and to Understanding the Distinctions and Similarities between Normal and Abnormal Growth

2010

Building on earlier work on abnormal SME growth trajectories, this paper investigates to what extent the analysis can be extended to the study of an unusual but “normal” growth pattern. The detailed case histories of two firms which might be called micro-giants are presented. These are companies that would be categorised as small firms but are actually competing, and competing successfully, in non-niche markets with much larger firms, or even multinational giants. The resource based view and modelling approaches developed in the earlier non-normal growth situations is then applied to these cases. It is argued that by viewing the management of strategic assets as part of the normal business …

Evaluation of Daylight Availability for Energy Savings.

2015

Dynamic daylight simulations are very useful instruments in daylighting design process. They allow an in depth analysis of indoor daylight availability levels and define if they are adequate to perform a particular visual task. Their results can be used to design shading devices or lighting control systems and compare different technical solutions. The use of these simulations is likely to spread in the common design practice since some regulations and green building rating systems suggest their use. This paper presents dynamic daylight simulation results related to an open-plan office, performed with Autodesk 3ds Max Design ® , which is a calculation software validated by recent researches…

On the history of torsional stress concentrations in shafts: From electrical analogies to numerical methods

2014

This article proposes a retrospective on experimental and numerical methods developed throughout the past century to solve the torsion problem in shafts, with particular emphasis on the determination of shear stress concentration factors in discontinuities of typical use in shaft design. This article, in particular, presents the theory and related solutions distinguishing between two classes of geometries: shafts with constant cross section and axisymmetric shafts with variable diameter. Emphasis is given to approaches based on physical analog methods and, in particular, those based on electrical analogies proposed since about 1925. Experimental methods based on structural physical models …

A new approach for deducing the stage-discharge relationship of triangular in plan sharp-crested weirs

2013

Abstract In this paper, the outflow process of a triangular in plan sharp-crested weir is studied using the dimensional analysis and the incomplete self-similarity theory. The new stage-discharge is theoretically deduced and its testing is carried out using measurements available in literature.

Peeling of multilayer graphene creates complex interlayer sliding patterns

2015

Peeling, shearing, and sliding are important mechanical phenomena in van der Waals solids. However, theoretically they have been studied mostly using minimal periodic cells and in the context of accurate quantum simulations. Here, we investigate the peeling of large-scale multilayer graphene stacks with varying thicknesses, stackings, and peeling directions by using classical molecular dynamics simulations with a registry-dependent interlayer potential. Simulations show that, while at large scale the peeling proceeds smoothly, at small scale the registry shifts and sliding patterns of the layers are unexpectedly intricate and depend both on the initial stacking and on the peeling direction.…

Giant collective incoherent shock waves in strong turbulence

2016

Contrary to conventional coherent shocks, we show theoretically and experimentally that nonlocal turbulent flows lead to the emergence of large-scale incoherent shock waves, which constitute a collective phenomenon of the incoherent field as a whole.

Capturing shock waves in inelastic granular gases

2005

Shock waves in granular gases generated by hitting an obstacle at rest are treated by means of a shock capturing scheme that approximates the Euler equations of granular gas dynamics with an equation of state (EOS), introduced by Goldshtein and Shapiro [J. Fluid Mech. 282 (1995) 75-114], that takes into account the inelastic collisions of granules. We include a sink term in the energy balance to account for dissipation of the granular motion by collisional inelasticity, proposed by Haff [J. Fluid Mech. 134 (1983) 401-430], and the gravity field added as source terms. We have computed the approximate solution to a one-dimensional granular gas falling on a plate under the acceleration of grav…