Search results for "Civil Engineering"

Hybrid Passive Control Strategies for Reducing the Displacements at the Base of Seismic Isolated Structures

2019

In this paper, the use of hybrid passive control strategies to mitigate the seismic response of a base-isolated structure is examined. The control performance of three different types of devices used for reducing base displacements of isolated buildings is investigated. Specifically, the Tuned Mass Damper (TMD), the New Tuned Mass Damper (New TMD) and the Tuned Liquid Column Damper (TLCD), each one associated to a Base Isolated structure (BI), have been considered. The seismic induced vibration control of base-isolated structures equipped with the TMD, New TMD or the TLCD is examined and compared with that of the base-isolated system without devices, using real recorded seismic signals as e…

Optimal design of tuned liquid column dampers for seismic response control of base-isolated structures

2017

In this paper, the use of a tuned liquid column damper (TLCD) as a cost-effective means to control the seismic response of a base-isolated structure is studied. A straightforward direct approach for the optimal design of such a device is proposed, considering a white noise model of the base excitation. On this base, a direct optimization procedure of the TLCD design parameters is performed and optimal design charts are presented as a ready-to-use practical design tool. Comparison with the optimal parameters obtained considering a classical iterative statistical linearization technique proves the reliability of the proposed approach. The performance of the base-isolated TLCD-controlled struc…

A multi-technique simultaneous approach for the design of a sailing yacht

2015

In this paper, most significant steps involved during the whole process of designing a sailing yacht are outlined. In particular, a novel simultaneous approach has been proposed to optimize the design process of a sailing yacht. Analytical resistance prediction models are simultaneously used with CAD systems and computational fluid dynamics tools to find, in the more effective way, the best solution for the chosen design conditions. As a general rule, in fact, once the target point has been decided, task of the designer is the definition of those systems of aerodynamic and hydrodynamic forces that are in equilibrium when the boat sails at its target. Unfortunately, a multi-purpose yacht doe…

A Workflow for the Performance Based Design of Naturally Ventilated Tall Buildings Using a Genetic Algorithm (GA)

2019

Optimization of Natural Ventilation process in highrise buildings is one of the most complex and least addressed phenomenon in the field of sustainable architecture. This issue requires urgent consideration to reduce the computation time due to fast growing demand of vertical construction in metropolitan cities. Until recently most highrise buildings have been operated with mechanical systems, causing high energy loads in hot climates and have high carbon footprints. Highrise buildings with natural ventilation and sky gardens can address these problems. This study involves the development of a Genetic Algorithm (GA) addressing the multi objective optimization of natural ventilation in tall …

Experimental modular stand used for studies of the High Tibial Osteotomy

2017

The optimization of the surgery strategies for the correction of the axial deviations of the human lower member presents a great importance both for the affected patients and for surgeons. This article seeks to develop a modular stand used mainly for experimental study of the High Tibial Osteotomy (HTO). In the article it is also shown the relation between the axial deviations of the human leg and their corrections using HTO. The modular devices were designed, executed and used in the experimental research.

Corrigendum to “Observer-Based Sliding Mode Control for Stabilization of a Dynamic System with Delayed Output Feedback”

2016

Static output-feedback control for vehicle suspensions: a single-step linear matrix inequality approach

2013

In this paper, a new strategy to design static output-feedback controllers for a class of vehicle suspension systems is presented. A theoretical background on recent advances in output-feedback control is first provided, which makes possible an effective synthesis of static output-feedback controllers by solving a single linear matrix inequality optimization problem. Next, a simplified model of a quarter-car suspension system is proposed, taking the ride comfort, suspension stroke, road holding ability, and control effort as the main performance criteria in the vehicle suspension design. The new approach is then used to design a static output-feedbackH∞controller that only uses the suspensi…

Dynamic Output Feedback Passive Control of Uncertain Switched Stochastic Systems with Time-Varying Delay

2013

Published version of an article in the journal: Mathematical Problems in Engineering. Also available from Hindawi: http://dx.doi.org/10.1155/2013/281747 Open Access This paper is concerned with the issues of passivity analysis and dynamic output feedback (DOF) passive control for uncertain switched stochastic systems with time-varying delay via multiple storage functions (MSFs) method. Firstly, based on the MSFs method, a sufficient condition for the existence of the passivity of the underlying system is established in terms of linear matrix inequalities (LMIs). Furthermore, the problem of dynamic output feedback passive control is investigated. Based on the obtained passivity condition, a …

Paediatric Sleep Questionnaire for Obstructive Sleep Apnoea Syndrome Screening: Is Sleep Quality Worthy of Note?

2021

Obstructive sleep apnoea syndrome (OSAS) is the most severe condition on the spectrum of sleep-related breathing disorders (SRBDs). The Paediatric Sleep Questionnaire (PSQ) is one of the most used and validated screening tools, but it lacks the comprehensive assessment of some determinants of OSAS, specifically anamnestic assessment and sleep quality. This study aims to assess the accuracy of some specific items added to the original PSQ, particularly related to the patient’s anamnestic history and to the quality of sleep, for the screening of OSAS in a paediatric population living in Sicily (Italy). Fifteen specific items, divided into “anamnestic” and “related to sleep quality” were added…

The Importance of Respecting the Psychological Contract by Managers

2021

The paper wants to be an alarm signal that non-compliance with the psychological contract by managers can negatively affect the organizational climate. The paper starts with a selection of the most important aspects of the literature on the psychological contract. The results of this study from secondary sources are interpreted in terms of the current socio-economic context, showing the possible negative influences of economic crises and pandemics such as COVID-19 on compliance with the psychological contract in organizations. The situations of violation of the psychological contract by the management can be numerous in this context. Therefore, the paper then presents an exploratory researc…