Search results for "system dynamic"

Supply chain modelling and analysis: an application of Latin square to a repeated coupling of non-linear differential equations

2011

In the last 50 years, Forrester’s system dynamics techniques have been adopted to analyse problems and find solutions for global supply chains. An important topic in production-inventory system modelling is the design of experiment. The aim of this paper is to present an application of a statistical technique of design of experiment, the Latin Square Design, to set a combination of input values for the initial-value problem of non-linear repeated coupling of first-order differential equations modelling a production-inventory system. This design permits to reduce the number of experiments while allowing statistical analysis for testing the significance of the studied parameters.

Simulations of networked critical infrastructures

2018

Master's thesis Information- and communication technology IKT590 - University of Agder 2018 Critical infrastructure (CI) refers to assets that are essential for the functioning of a society and economy, such as telecommunication/ICT; energy generation, transmission and distribution; financial sector; etc. CIs are tightly coupled, creating a complex system where failures propagate from a disrupted CI to other CIs, aggravating and prolonging the societal impact through cascading effects. This thesis extends a system dynamic model by Eliza Canzani describing how a failed critical infrastructure that cannot deliver products and services impacts other critical infrastructures, and how a critical…

Evolution of a Non-Hermitian Quantum Single-Molecule Junction at Constant Temperature

2021

This work concerns the theoretical description of the quantum dynamics of molecular junctions with thermal fluctuations and probability losses. To this end, we propose a theory for describing non-Hermitian quantum systems embedded in constant-temperature environments. Along the lines discussed in [A. Sergi et al., Symmetry 10 518 (2018)], we adopt the operator-valued Wigner formulation of quantum mechanics (wherein the density matrix depends on the points of the Wigner phase space associated to the system) and derive a non-linear equation of motion. Moreover, we introduce a model for a non-Hermitian quantum single-molecule junction (nHQSMJ). In this model the leads are mapped to a tunneling…

Overcoming traditional Performance Management in Public Healthcare Institutions: The need for a DPM Approach

Donabedian (1988) was the scientific father of the notion that Performance Measurement (PM) of hospital outputs leads to improved quality of healthcare services, setting the foundations of how hospital quality is still today defined, considered and measured using three different kinds of measures: structure, process and outcome measures. Nonetheless, a growing part of literature during the last two decades has started doubting those favourable outcomes of PM on hospital quality (De Vos, et al., 2009; Nolan & Berwick, 2006; Werner et al., 2008a, 2008b; Werner & Bradlow, 2006; Wright & Hershman, 2014) while other research shows that ineffective PM systems are not just useless but …

POLICY INNOVATION AND IMPLEMENTATION IN PUBLIC SECTOR: COMPLEXITIES, DYNAMICS AND UNCERTAINTIES

This research is expected to contribute to the knowledge base on how an effective impact assessment and adoption of innovations in the public sector could be facilitated. The need for trans-disciplinary assessment of the long-term potential impacts of innovation-driven policies may well be met with system dynamics as part of the dynamic performance management approach by way of modelling based simulation and analysis. Moreover, such analysis may contribute to learning and the accumulation of a knowledge repository that enables strategy developers, policy designers and decision makers to arrive at unexpected (often called counterintuitive) conclusions prior to policy implementation. Such ins…

Learning about Dynamic Problems with Computer Simulators: A Case of System Dynamics Simulation Models

2008

A vast body of research shows that people by and large fail to understand and manage dynamic environments. Given the increasing complexity of our world, there is an urgent need to develop more effective ways to present dynamic problems. Many studies propose computer simulators as virtual learning environments to help people understand and manage complex problems. Still, experimental data show that simulators often carry problems from reality into the virtual laboratory. An analysis from the perspective of cognitive load theory suggests that learning about complex problems could be improved by enhancing descriptions with simulation elements that would facilitate interactive exploration of th…

On the Non-Intrusive Load Monitoring in dwellings: a feasibility perspective

2021

The oncoming modernization process of the power grids, driven above all by decarbonisation objectives and the continuous improvement of digital technologies, is encouraging active participation in the electricity market by consumers through the Demand-Response mechanism. From this perspective, the introduction of smart meters and energy consumption monitoring devices plays a fundamental role, being able to give benefits to consumers, suppliers and the electricity grid itself. This paper proposes a supervised method of non-intrusive load monitoring (NILM) based on the recognition of patterns in the time domain with the Dynamic Time Warping algorithm which is suitable for low-cost smart meter…

E-Government's Role in Shifting the Paradigm of Performance in the Public Sector

2015

The emergence of e-government changed the world of the Public Administration (PA) and the discipline of Public Management dramatically. Through the presentation of a case- study of the municipality of Palermo, this article attempts to discuss the renewed need for assessing performance of e-government services in a local government and to disclose the main critical issues in accomplishing this evaluation. Palermo is experiencing the implementation of a second- generation e-government project that is embodied in the realization of a web portal. The conceptualization of a framework to assess the performance of the digital services appears to be crucial in order to improve the system and to avo…

An optimized system dynamics approach for a hotel chain management

2009

The proposed model consists of an integrated system dynamics-data envelopment analysis approach to value, in a dynamic framework, the effects over time of the policies implemented according to the relative efficiency analysis. Rooms’ price and competing facilities (the hedonics) are the decision variables to move in order to push the hotels towards a higher relative efficiency at the end of the observation periods. In fact, in competitive markets as tourism, hotels compete for money offering differentiated quality. Moreover, according to the microeconomic theory, a producer of differentiated goods is not a price taker but a price maker. Therefore, we assume that the decision maker of the ho…

Impact of COVID-19 on the travel and tourism industry.

2021

Abstract Our paper is among the first to measure the potential effects of the COVID-19 pandemic on the tourism industry. Using panel structural vector auto-regression (PSVAR) (Pedroni, 2013) on data from 1995 to 2019 in 185 countries and system dynamic modeling (real-time data parameters connected to COVID-19), we estimate the impact of the pandemic crisis on the tourism industry worldwide. Past pandemic crises operated mostly through idiosyncratic shocks' channels, exposing domestic tourism sectors to large adverse shocks. Once domestic shocks perished (zero infection cases), inbound arrivals revived immediately. The COVID-19 pandemic, however, is different; and recovery of the tourism ind…