Search results for "System Dynamics."
showing 10 items of 187 documents
Determinants of performance drivers in online food delivery platforms: a dynamic performance management perspective
2022
PurposeThis study aims to demonstrate that the Dynamic Performance Management (DPM) framework, integrating performance management with system dynamics modelling, enables decision-makers to identify sustainable strategies in online food delivery platforms, thereby avoiding company failure.Design/methodology/approachThis study undertakes a multistep methodological approach. After the literature review, a retrospective case study approach was used. To build the DPM framework and the system dynamics simulation model, primary and secondary data were collected and analysed.FindingsThis study by adopting the DPM perspective highlights the critical role performance drivers play to assess the viabil…
Supporting the natural gas supply chain public policies through simulation methods: A dynamic performance management approach
2018
Natural gas is considered the transitional fuel par excellence between fossil and renewable sources, considering its low cost, greater efficiency and lesser impact on the environment. This is the reason why its demand levels have increased worldwide, requiring intervention of public and private stakeholders in order to meet these increments. The participation of diverse interconnected stakeholders (key actors) of the supplier-client form, constitutes a supply chain for natural gas, in which the effects of the application of public policy actions can be analysed in the time, using Dynamic Performance Management DPM methodology. The results of the model show the behaviour of the reserves, pro…
A Dynamic Simulation Approach to Frame Drivers and Implications of Corruption Practices on Firm Performance
2014
Corruption is a multifaceted socio-economic phenomenon widely spread – although with different intensity – all around the world. Many studies on corruption have been conducted at a country-level, but relatively little effort has been placed in evaluating its implications, in terms of both financial and competitive performance, at a firm-level. Therefore, this paper aims at exploring the causal relationships underlying the effect of corruption on firm performance in order to show the different scenarios that may emerge from the combination between external (i.e., contextual conditions) and internal (i.e., organizational characteristics) forces that drive corruption. To this end, we adopt a D…
System Dynamics : Theory and Applications ; Edited by Brian Dangerfield
2021
The Springer volume on “System Dynamics. Theory and Applications” (2020), edited by Brian Dangerfield, substantially contributes to strengthening the position of feedback modeling and simulation in both research and practice in various policy analysis domains. The 23 chapters, of which the book consists, cover a wide scope of fields ranging from theory and methodology (part II) to practical applications of system dynamics (SD) to solve different real-life problems (part III). In particular, the methodological chapters provide a suitable conceptual framework for the subsequent chapters which illustrate the benefits from applying SD to specific policy fields and contexts. A well-balanced mix …
Composite quantum collision models
2017
A collision model (CM) is a framework to describe open quantum dynamics. In its {\it memoryless} version, it models the reservoir $\mathcal R$ as consisting of a large collection of elementary ancillas: the dynamics of the open system $\mathcal{S}$ results from successive "collisions" of $\mathcal{S}$ with the ancillas of $\mathcal R$. Here, we present a general formulation of memoryless {\it composite} CMs, where $\mathcal S$ is partitioned into the very open system under study $S$ coupled to one or more auxiliary systems $\{S_i\}$. Their composite dynamics occurs through internal $S$-$\{S_i\}$ collisions interspersed with external ones involving $\{S_i\}$ and the reservoir $\mathcal R$. W…
Full- and Reduced-order Model of Hydraulic Cylinder for Motion Control
2017
This paper describes the full- and reduced-order models of an actuated hydraulic cylinder suitable for system dynamics analysis and motion control design. The full-order model incorporates the valve spool dynamics with combined dead-zone and saturation nonlinearities - inherent for the orifice flow. It includes the continuity equations of hydraulic circuits coupled with the dynamics of mechanical part of cylinder drive. The resulted model is the fifth-order and nonlinear in states. The reduced model neglects the fast valve spool dynamics, simplifies both the orifice and continuity equations through an aggregation, and considers the cylinder rod velocity as output of interest. The reduced mo…
Stochastic Response Of Fractionally Damped Beams
2014
Abstract This paper aims at introducing the governing equation of motion of a continuous fractionally damped system under generic input loads, no matter the order of the fractional derivative. Moreover, particularizing the excitation as a random noise, the evaluation of the power spectral density performed in frequency domain highlights relevant features of such a system. Numerical results have been carried out considering a cantilever beam under stochastic loads. The influence of the fractional derivative order on the power spectral density response has been investigated, underscoring the damping effect in reducing the power spectral density amplitude for higher values of the fractional de…
Moment Equations for a Spatially Extended System of Two Competing Species
2005
The dynamics of a spatially extended system of two competing species in the presence of two noise sources is studied. A correlated dichotomous noise acts on the interaction parameter and a multiplicative white noise affects directly the dynamics of the two species. To describe the spatial distribution of the species we use a model based on Lotka-Volterra (LV) equations. By writing them in a mean field form, the corresponding moment equations for the species concentrations are obtained in Gaussian approximation. In this formalism the system dynamics is analyzed for different values of the multiplicative noise intensity. Finally by comparing these results with those obtained by direct simulat…
Cooling of Many-Body Systems via Selective Interactions
2018
We propose a model describing $N$ spin-1/2 systems coupled through $N$-order homogeneous interaction terms, in presence of local time-dependent magnetic fields. This model can be experimentally implemented with current technologies in trapped ions and superconducting circuits. By introducing a chain of unitary transformations, we succeed in exactly converting the quantum dynamics of this system into that of $2^{N-1}$ fictitious spin-1/2 dynamical problems. We bring to light the possibility of controlling the unitary evolution of the $N$ spins generating GHZ states under specific time-dependent scenarios. Moreover, we show that by appropriately engineering the time-dependence of the coupling…
Temperature effects on quantum non-Markovianity via collision models
2018
Quantum non-Markovianity represents memory during the system dynamics, which is typically weakened by the temperature. We here study the effects of environmental temperature on the non-Markovianity of an open quantum system by virtue of collision models. The environment is simulated by a chain of ancillary qubits that are prepared in thermal states with a finite temperature $T$. Two distinct non-Markovian mechanisms are considered via two types of collision models, one where the system $S$ consecutively interacts with the ancillas and a second where $S$ collides only with an intermediate system $S'$ which in turn interacts with the ancillas. We show that in both models the relation between …