Search results for "Simulation."

Coordination policies to support decision making in distributed production planning

2003

Abstract Distributed production networks are considered organizational structures able to match agility and efficiency necessary to compete in the global market. Performances of such organization structures heavily depend on the ability of the network actors of coordinating their activities. The research proposes to model and design coordination problems within production network by using the Multiple Agent Technology. In particular, the paper proposes new strategies for coordinating production-planning activities within production networks. Such models have been developed and tested by using a proper simulation environment developed by using open source code and architecture. The results o…

Analysis, Modeling and Simulation of Complex Regional Clusters Activities, Using Arena Simulation Software

2014

Process modelling is the concise description of the total variation in one quantity, y, by partitioning it into a deterministic component given by a mathematical function of one or more other quantities, x1, x2... plus a random component that follows a particular probability distribution. The models are material or immaterial systems, which represent other systems, so that it may be possible to manipulate the built structures and their states. The main elements of a simulation are: attributes (describe and differentiate entities), variables (system characteristics), resources (whose capacity can be variable), tails (seen in case of unavailability of resources) and statistical accumulators (…

Monte Carlo simulation for the response analysis of long-span suspended cables under wind loads

2004

This paper presents a time-domain approach for analyzing nonlinear random vibrations of long-span suspended cables under transversal wind. A consistent continuous model of the cable, fully accounting for geometrical nonlinearities inherent in cable behavior, is adopted. The effects of spatial correlation are properly included by modeling wind velocity fluctuation as a random function of time and of a single spatial variable ranging over cable span, namely as a one-variate bi-dimensional (1V-2D) random field. Within the context of a Galerkin`s discretization of the equations governing cable motion, a very efficient Monte Carlo-based technique for second-order analysis of the response is prop…

Rear-view mirror use, driver alertness and road type: An empirical study using EEG measures

2006

Abstract The use of rear-view mirrors has been suggested as a good behavioural indicator of driver alertness in traffic situations (Brookhuis, K. A., De Vries, G., & De Waard, D. (1991). The effects of mobile telephoning on driving performance. Accident Analysis and Prevention, 23 (4), 309–316). In general terms, drivers look in the mirrors to find information and adapt their driving to traffic variations. This paper aims to analyse the links between time variations in alertness—measured from EEG activity data—and the frequency of rear-view mirror use in a group of drivers, both on motorways and conventional roads. The results point to a direct relationship between alertness level and mirro…

Off-line path correction of robotic face milling using static tool force and robot stiffness

2015

In this paper the developed method for off-line compensation of tool deflections when milling aluminum with an industrial robot is presented. The efficiency of this approach is verified with high precision measurements of deflections using a laser tracker. The compensation method includes both the static milling process model which can predict the mean value components of the tool forces and a new combined local/global approach for estimating the combined stiffnesses of joints. With a process model such as the one presented in this paper and estimates of the robot's joint stiffness values, the tool path can be adjusted to counteract deflections of the tool during milling operations. The mod…

Exploring the uncertainty in capacity estimation at roundabouts

2017

Abstract Purpose In gap-acceptance theory the critical and the follow-up headways have a significant role in determining roundabout entry capacities which in turn depend on circulating flow rates under a specified arrival headway distribution. Calculation considers single mean values of the gap-acceptance parameters, neglecting the inherent variations in these random variables and providing a single value of entry capacity. The purpose of this paper is to derive the entry capacity distribution which accounts for the variations of the contributing (random) variables and suggest how to consider this issue in the operational analysis of the roundabouts. Methods We performed a Monte Carlo simul…

Lighting control systems: Factors affecting energy savings' evaluation

2015

Abstract The use of automated lighting control systems allows to reduce lighting costs and to achieve significant energy savings. The energy performances of controls are affected by many factors, the impact of which is very difficult to account for during the design process. The goal of this paper is to describe the factors that influence the control systems’ energy performances, to analyze how the currently available calculation tools take them into account and finally to propose a simple method to adjust results obtained from the simulation software.

A simple and accurate model of photovoltaic modules for power system design

2014

Finite-element Discretizations of Semiconductor Energy-transport Equations

2003

Energy-transport models describe the flow of electrons in a semiconductor crystal. Several formulations of these models, in the primal or dual entropy variables or in the drift-diffusion-type variables, are reviewed. A numerical discretization of the steady-state drift-diffusion-type formulation using mixed-hybrid finite elements introduced by Marini and Pietra is presented. The scheme is first applied to the simulation of a one-dimensional ballistic diode with non-parabolic band diagrams. Then a two-dimensional deep submicron MOSFET device with parabolic bands is simulated, using an adaptively refined mesh.

Angle Factors and Projected Area Factors for Comfort Analysis of Subjects in Complex Confined Enclosures: Analytical Relations and Experimental Resul…

2008

This paper addresses an important problem in the evaluation of the thermal comfort of people living or working in the sort of confined spaces typical of current architecture. In the details, a new algorithm is proposed for the evaluation of the angle factors of people within rooms characterized by complex shapes, where the envelope components are not always mutually orthogonal. The algorithm is based on field data obtained by means of an experimental photographic apparatus which allows measurements of projected area factors of seated or standing people in such complex confined environments.