Search results for " drive"

A Theoretical Approach to the Shift Mechanics of Rubber Belt Variators

2008

This paper proposes a theoretical description of the mechanical behavior of rubber belt variators during the speed ratio shift. Comparing with the steady operation, the mass conservation of the belt is completely reformulated considering an elementary dihedral control volume between two planes through the pulley axis and balancing the inside mass variation with the total mass flux through the control surface. On the other hand, the belt equilibrium conditions are similar to the steady case, as the inertia forces due to the shifting motion are negligible with respect to the other forces. Assuming a one-dimensional belt model, it is shown that adhesive regions may appear inside the arc of con…

Electrical connections and driving electronics for piezo-actuated x-ray thin glass optics

2016

Use of thin glass modular optics is a technology currently under study to build light, low cost, large area X-ray telescopes for high energy astrophysics space missions. The angular resolution of such telescopes is limited by local deviations from the ideal shape of the mirrors. One possible strategy to improve it consists in actively correcting the mirror profile by gluing thin ceramic piezo-electric actuators on the back of the glasses. A large number of actuators, however, requires several electrical connections to drive them with the different needed voltages. We have developed a process for depositing conductive paths directly on the back of non-planar thin foil mirrors by means of a p…

Uncertainty evaluation in the differential measurements of power losses in a power drive system

2021

Abstract In order to guarantee a correct classification in the standardized energy efficiency classes, the current standards concerning the power drive systems prescribe that their power losses must be evaluated with great accuracy. This circumstance involves the usage of expensive measurement systems, since accurate instrumentation, skilled personnel and controlled environments are required. During the design stage of a power drive system, however, the measurement of the absolute value of its power losses is not always needed. Often, in fact, it is enough to assess the power losses variations caused by a modification of either hardware or software sections of the power drive system. In the…

About the Ghosh Model: Clarifications

2007

We examine the consistency of the Ghosh supply-d riven input-output model (SM) by respect to the traditional Leontief demand-drive n input-output model (LM); the variants considered are: primal and dual, quantity and value ; input prices are not considered. SM offers solutions of limited interest, being incapab le to separate quantities and prices or values and price indexes. Comparing the dual value SM to the primal of LM is wrong. Even if the agents are forced to buy inputs in SM, the interpre tation of SM as a centrally planned economy must be rejected but SM may serve for modeling interfirm relations or analyzing the structural interindustry change when the production function is not sp…

Learning Pros and Cons of Model-Driven Development in a Practical Teaching Experience

2016

Current teaching guides on Software Engineering degree focus mainly on teaching programming languages from the first courses. Conceptual modeling is a topic that is only taught in last courses, like master courses. At that point, many students do not see the usefulness of conceptual modeling and most of them have difficulty to reach the level of abstraction needed to work with them. In order to make the learning of conceptual modeling more attractive, we have conducted an experience where students compare a traditional development versus a development using conceptual models through a Model-Driven Development (MDD) method. This way, students can check on their own pros and cons of working w…

Reengineering an Approach to Model-Driven Development of Business Apps

2015

Despite a perceived convergence in mobile application development, platforms such as Android and iOS remain largely incompatible. Supporting multiple platforms currently requires either separate native development (for each system) or utilization of a cross-platform development framework. While many such frameworks have been developed, only few are mature and even less are used widely, let alone commercially. Moreover, they typically are limited with regard to performance and to preserving a native look & feel. Worst of all, their usefulness for business apps is limited due to their low level of abstraction. In this paper, we take a closer look at an academic prototype that employs model-dr…

Session details: Agent-oriented methodologies, infrastructures and processes track

2010

Work stress and health problems of professional drivers: A hazardous formula for their safety outcomes

2018

BackgroundSeveral empirical studies have shown that professional drivers are a vulnerable occupational group, usually exposed to environmental stressors and adverse work conditions. Furthermore, recent studies have associated work-related stress with negative job performances and adverse health outcomes within this occupational group, including cardiovascular diseases and unsafe vehicle operation.ObjectiveThe aim of this study was to describe the working conditions and the health status of this occupational group, and to evaluate the association between the Demand–Control model of job stress and their self-reported health and safety outcomes.MethodsA pooled sample of 3,665 Colombian profess…

Combining a data-driven approach with seasonal forecast data to predict reservoir water volume in the Mediterranean area

2023

Prolonged droughts and water scarcity have become more frequent in recent years, exacerbating the problem of the artificial reservoirs management in the Mediterranean area. This study proposes a methodology which combines a Nonlinear AutoRegressive network with eXogenous input (NARX) data-driven model with Seasonal Forecasts (SFs) data, with the aim to predict the water volume stored in reservoirs at a mid-term scale, as requested by the local authority. The methodology is applied to four Sicilian reservoirs that experienced water scarcity in the recent past. SFs produced at the European Centre for Medium-Range Weather Forecasting are used to force the NARX models. Also, the reservoirs are …

Sensorless induction machine drive for fly-wheel generation unit based on a TLS-based non-linear observer

2016

This paper proposes a sensorless technique for an induction machine Flywheel Energy Storage System (FESS) based on a non-linear observer integrated with a total least-squares speed estimator taking into consideration the IM (Induction Machine) saturation effects. The nonlinear observer is based on an original formulation of the dynamic model of the IM including the magnetic saturation, rearranged in a space-state form, after assuming as state variables the stator current and the rotor magnetizing current space-vectors in the stator reference frame. The choice of the observer gain has been made by the use of Lyapunov's method. The speed signal needed by the non-linear observer for the flux e…