Search results for "Variables"
showing 10 items of 578 documents
The effects of fiscal policy shocks on the business environment
2021
Fiscal policy influences economic conditions through public spending and taxes, generating positive or negative impulses, both on short and long term. The present research focuses on analysing the effects of the discretionary changes in the fiscal policy in seven post-communist countries of the European Union during the period 2000–2018. The autoregressive distributed lag model (ARDL) has been applied in order to obtain the convergence rates to equilibrium with a clear analysis of the periods needed to achieve the long-run fiscal sustainability. Also, the error correction vector model (VECM), which is based on the autoregressive vector (VAR) model, has been used in the second part of the an…
Institutional, pedagogical, psychosocial and socio-demographic factors related to academic performance at the University of Costa Rica: a multilevel …
2007
A multilevel analysis was conducted to predict final grades in courses from different majors for a sample, stratified by academic areas, of 848 students at the University of Costa Rica. A group of factors from institutional, socio-demographic, psychosocial and pedagogical aspects were employed as independent variables. The best predictor was the Admission Average, which combines grades from high school and an aptitude test score. Some non-cognitive variables were also explicative; the most important being the score on a scale of emotional intelligence. The methodology employed by the professor showed explicative power as well.
Emotional and behavioral problems in children with attention deficit-hyperactivity disorder: Impact of age and learning disabilities
2008
Comorbidity with other psychological problems (PP) complicates the course of attention deficit-hyperactivity disorder (ADHD) and makes treatment more difficult. The purpose of the present study was to (a) study the correspondence between the perceptions of parents and teachers about PP, (b) determine which PP predict the severity of the manifestations of ADHD, and (c) analyze the role of age and learning disabilities (LD) in the development of PP and ADHD. The participants were 72 children with a clinical diagnosis of ADHD. The PP were measured using rating scales filled out by parents and teachers. The results showed high correspondence between the two informant groups in rating the probl…
Instructional support predicts children’s task avoidance in kindergarten
2011
Abstract This study examined the role of observed classroom quality in children's task-avoidant behavior and math skills in kindergarten. To investigate this, 1268 children were tested twice on their math skills during their kindergarten year. Kindergarten teachers ( N = 137) filled in questionnaires measuring their professional experience and also rated the children on their task-avoidant versus task-focused behaviors. Trained observers used the CLASS instrument ( Pianta, La Paro, & Hamre, 2008 ) to observe 49 kindergarten teachers (out of 137) on their emotional support, classroom organization, and instructional support. The results of multilevel modeling showed that kindergarten classro…
Knowledge creation. The ongoing search for strategic renewal
2014
Purpose– The purpose of this paper is to analyse how changes in a set of structural design variables (i.e. liaison position, networked design, innovation teams and work teams) affect the creation of new knowledge within organizations. The enablers intention, autonomy, fluctuation and creative chaos, redundancy, variety, and trust and commitment, taken from Nonaka's framework, are used as intermediate variables.Design/methodology/approach– A sample of 167 large Spanish companies was used to empirically test a general relational model.Findings– The analysis yielded two main conclusions. First, the relationship between structural variables and enablers, and, second, the relationship of enabler…
Scalable and Privacy-Preserving Admission Control for Smart Grids
2015
International audience; Energy demand and production need to be constantly matched in the power grid. The traditional paradigm to continuously adapt the production to the demand is challenged by the increasing penetration of more variable and less predictable energy sources, like solar photovoltaics and wind power. An alternative approach is the so called direct control of some inherently flexible electric loads to shape the demand. Direct control of deferrable loads presents analogies with flow admission control in telecommunication networks: a request for network resources (bandwidth or energy) can be delayed on the basis of the current network status in order to guarantee some performanc…
Risk Assessment of a compound feed process based on HAZOP analysis and linguistic terms
2016
[EN] The size and complexity of industrial plants, along with the characteristics of the products used, require a study, analysis and control of the existing risks in every industrial process. In this paper, a methodology for risk assessment in industrial plants, based on the combination of risks identification through the Hazard and Operability (HAZOP) analysis and the risks evaluation through linguistic variables and fuzzy numbers is applied to a case study consisting on a compound feed plant located in the town of Silla (Valencia, Spain). The results from this study show that the main risk in the compound feed production process is the formation of explosive atmospheres (ATEX). Therefore…
Optimum Performance of Permanent Magnet Synchronous Generators Coupled to Wind Turbines
2007
In this paper a control algorithm for the efficiency improvement of permanent magnet synchronous generators (PMSG) is presented. The proposed algorithm reduces the losses of the generator without affecting its performances. In details, after a description of a dynamic model of the PMSG, which has been purposely modified in order to take into account the iron losses, the basic equations and the constraints to obtain the loss minimization are presented and discussed. Some simulations of a specific PMSG employing the proposed algorithm are performed. The results of these simulations show that enhancement of the efficiency up to 3% can be reached in comparison to a PMSG using a traditional cont…
A Monte Carlo Method for the Auto-Evaluation of the Uncertainties in the Analog-to-Digital Conversion-Based Measurements
2004
This paper concerns with the measurement uncertainty estimation in the analog‐to‐digital conversion‐based instruments. By using an ad hoc developed software tool, the Monte Carlo method is applied in order to assess the uncertainties associated with the measurement results, overcoming the possible inapplicability of the pure theoretical approach prescribed in the ISO – “Guide to the Expression of Uncertainty in Measurement”. By implementing the software tool in the measurement instruments, the proposed approach can be utilized in order to make the instrument itself able to auto‐estimate the measurement uncertainties.
Design optimization on the drive train of a light-weight robotic arm
2011
A drive train optimization method for design of light-weight robots is proposed. Optimal selections of motors and gearboxes from a limited catalog of commercially available components are done simultaneously for all joints of a robotic arm. Characteristics of the motor and gearbox, including gear ratio, gear inertia, motor inertia, and gear efficiency, are considered in the drive train modeling. A co-simulation method is developed for dynamic simulation of the arm. A design example is included to demonstrate the proposed design optimization method.