Search results for "Civil Engineering"
showing 10 items of 1216 documents
Stabilization of a Class of Stochastic Nonlinear Systems
2013
This paper addresses two control schemes for stochastic nonlinear systems. Firstly, an adaptive controller is designed for a class of motion equations. Then, a robust finite-time control scheme is proposed to stabilize a class of nonlinear stochastic systems. The stability of the closed-loop systems is established based on stochastic Lyapunov stability theorems. Links between these two methods are given. The efficiency of the control schemes is evaluated using numerical simulations.
Dynamic Output-Feedback Passivity Control for Fuzzy Systems under Variable Sampling
2013
Published version of an article in the journal: Mathematical Problems in Engineering. Also available from the publisher at: http://dx.doi.org/10.1155/2013/767093 Open Access This paper concerns the problem of dynamic output-feedback control for a class of nonlinear systems with nonuniform uncertain sampling via Takagi-Sugeno (T-S) fuzzy control approach. The sampling is not required to be periodic, and the state variables are not required to be measurable. A new type fuzzy dynamic output-feedback sampled-data controller is constructed, and a novel time-dependent Lyapunov-Krasovskii functional is chosen for fuzzy systems under variable sampling. By using Lyapunov stability theory, a sufficie…
Using the modern CNC controllers capabilities for estimating the machining forces during the milling process
2017
Machining forces can nowadays be measured by using 3D dynamometers, which are usually very expensive devices and hardly available for most of the CNC machine-tools users. On the other hand, modern CNC controllers have nowadays the ability to display and save many outputs within the machining process, such as the currents or even the torques at the shaft's level for the feed motors on each axis. These outputs can be used for estimating the machining forces, but it is to be noticed that the above-mentioned currents and torques are proportional with the overall resistant forces, which includes not only technological forces, but also friction, inertial and pre-tensioning forces. This paper pres…
Optimizing the magnetic circuit of an actuator
2019
The paper presents a modern method of constructive optimization of a plunger actuator with axial symmetry based on the electromagnetic simulation of several variants of magnetic circuit and excitation currents. On the basis of the force calculation developed by this actuator and the magnetic induction values in the core, we calculated the kinematic actuator parameters. Experimental determinations confirmed the precision and utility of the optimization method by electromagnetic simulation of the actuator.
Well-being, behavioral patterns and cycling crashes of different age groups in Latin America: Are aging adults the safest cyclists?
2019
ObjectivesThis study aimed at analyzing the cycling safety-related factors and the mental health indicators of elderly cyclists in comparison with other age groups.MethodsFor this cross-sectional study, we analyzed the data of 911 bicyclists from two Latin American countries that have been experiencing a substantial growth of urban cycling during the last few years: Colombia and Argentina. Participants responded to an e-questionnaire on bicycling behaviors, mental health and cycling safety.ResultsAging adults reported lower rates of risky behaviors and traffic crashes (around .38 in five years), and, on the other hand, more cycling protective behaviors, a higher risk perception and a better…
Job stress and emotional exhaustion at work in Spanish workers: Does unhealthy work affect the decision to drive?
2020
Objectives The purpose of this study was to assess the relationships among the following elements: unhealthy work indicators (job stress and emotional exhaustion at work), the decision to drive (or not), and driving crashes suffered by Spanish workers. Methods For this cross-sectional study, a full sample of 1,200 Spanish drivers (44% women and 56% men) was used, their mean age being 42.8 years. They answered a questionnaire divided into three sections: demographic and driving-related data; burnout, job stress, and life stress; and self-reported road behaviors and driving safety indicators. Results Overall, 41.6% of drivers reported emotional exhaustion at work. Furthermore, 80.2% of the pa…
Influence of sexual appeal in roadside advertising on drivers' attention and driving behavior.
2019
Sexual appeals are widely used in advertising to attract consumers' attention. It has already been proved that they influence the addressee's cognitive processing, which in turn raises the question if sexual appeals may pose a serious threat for road safety when used in roadside advertising. Three studies were designed to answer this question. Study I was a nationwide survey (N = 1095) which revealed that drivers subjectively perceive sexual contents in roadside advertising as distracting and dangerous. Study II was a modified version of the Attentional Network Test (N = 1063) which proved that in cognitive tasks reaction time increases in line with the sexual content of advertisements. Stu…
Can't simply roll it out: Evaluating a real-world virtual reality intervention to reduce driving under the influence.
2020
Driving under the influence (DUI) increases the risk of crashes. Emerging technologies, such as virtual reality (VR), represent potentially powerful and attractive tools for the prevention of risky behaviours, such as DUI. Therefore, they are embraced in prevention efforts with VR interventions primed to grow in popularity in near future. However, little is known about the actual effectiveness of such DUI-targeting VR interventions. To help fill the knowledge gap, this study explored the effects of one VR intervention as delivered in the real world. Using pre and post test design, including an intervention group (n = 98) and a control group (n = 39), the intervention evaluation examined you…
Study regarding the influence of material type on economic objectives in MEx fabrication
2021
Material Extrusion has been used extensively as an additive manufacturing technology for a variety of applications like visual models, functional prototypes, tooling components, patterns for castings, and final parts. The current research paper proposes a study on the material type influence on economic objectives in material extrusion fabrication of complex assemblies. Three economic objectives have been analysed, namely, estimated fabrication time, material usage and material cost, whilst two commercial additive manufacturing machines have been considered for the simulation. Cura and ZSuite slicing software were used for the generation of Gcode and project files. Five filaments were selec…
Macroelement Model for In-Plane and Out-of-Plane Responses of Masonry Infills in Frame Structures
2018
A new macroelement model is presented in this paper for the simulation of the in-plane (IP) and out-of-plane (OOP) response of infilled frames subjected to seismic actions. The model consists of two diagonal, one horizontal, and one vertical struts. Each strut is represented by two fiber-section beam-column elements. The model is able to capture the arching action of the wall under an OOP load as well as the interaction between the IP and OOP actions. The proposed modeling approach is sufficiently simple and efficient that it can be used for the static or dynamic analysis of an entire structural system. An experimental validation has been carried out. A further numerical study performed wit…