Search results for "evaluation"
showing 10 items of 1974 documents
Uncertainty evaluation in the measurements for the electric power quality analysis
2013
The paper deals with the uncertainty estimation in the measurements performed to assess the electric power quality. In a first steps, according to the 'ISO - Guide to Expression of the Uncertainty in Measurements' all the error sources, which give a significant contribution to the combined uncertainty associated to the measurement results, are identified. Successively, in order to analyze how the errors propagate through the measurement chain, a Monte Carlo based approach is proposed. The method exploits an ad-hoc developed simulator of the measurement process, which takes into account the particular way of propagation of all the identified error sources. Eventually, with the aim of validat…
Mismatches between objective parameters and measured perception assessment in room acoustics: a holistic approach
2014
Psychoacoustic research in the field of concert halls has revealed that many aspects concerning listening perception have yet to be totally understood. On the one hand, the objective room acoustics of performance spaces are reflected in parameters, some standardized and some not, but these are related to a limited number of perceptual attributes of human response. In general, these objective parameters cannot accurately describe the acoustic details due to their inherent simplification. Under these premises, impulse responses (576 receivers) are measured in 16 concert halls, according to standard procedures, and the perception and satisfaction of the occupants of the rooms are evaluated by …
A PC-based wattmeter for high accuracy power measurements
2010
This paper proposes the use of a commercial data acquisition board (DAQ) connected to a common personal computer for high accuracy power measurements. In the paper the set up of the PC-based wattmeter is described and an experimental evaluation of its metrological performances is made by means of the comparison with a simultaneous coherent digital sampling wattmeter realized with two high-precision DMMs Hewlett Packard Model 3458 A. In both cases the power source is a Fluke 6100A/E electrical power standard. © 2010 IEEE.
Economic evaluation of PV system for EV charging stations: Comparison between matching maximum orientation and storage system employment
2016
This article addresses the problem of the choice of a generation system to be implemented to reduce the impact of charging electric vehicles at University. Based on the behaviour of the student population, it is identified the electrical load. Two possible solutions are evaluated in order to manage the peak load: an orientation of the panels in order to increase the power at defined time and the use of storage system. The main strength and weakness points of two systems are investigated by taking into account the Levelized Cost of Energy.
The Performance Evaluation of Polytechnic Higher Education Institutions: Tensions and Reconfigurations Resulting from the Adoption of Specific Metrics
2017
Aligned with the binary structure of the higher education system in Portugal, divided into universities and polytechnics, the Government acknowledged, in 2014, the need to identify distinct performance indicators/metrics aiming at a more accurate assessment of the effect and quality of the action developed by Higher Education Institutions (HEIs). For the Polytechnic Higher Education Institutions (PHEIs) it was necessary to define «(...) performance indicators that address the production, transfer and diffusion of knowledge» (FCT, 2014: 1), aiming to measure «(...) the applied research and the cultural production activities as well as their impact on the region where they [PHEIs] are located…
A proposal to elicit usability requirements within a model-driven development environment
2014
[EN] Nowadays there are sound Model-Driven Development (MDD) methods that deal with functional requirements, but in general, usability is not considered from the early stages of the development. Analysts that work with MDD implement usability features manually once the code has been generated. This manual implementation contradicts the MDD paradigm and it may involve much rework. This paper proposes a method to elicit usability requirements at early stages of the software development process such a way non-experts at usability can use it. The approach consists of organizing several interface design guidelines and usability guidelines in a tree structure. These guidelines are shown to the an…
Battery storage systems for peak load shaving applications: Part 2: Economic feasibility and sensitivity analysis
2016
This paper is the second of a two-part series, aiming to evaluate the economic feasibility of electrochemical storage systems in peak load shaving applications. The battery energy storage system (BESS) is considered to be added to a private facility, with the aim of reducing the customer electricity bill. The BESS is charged during the night, when the electricity prices are the lowest and discharged during the daily hours, when the prices are the highest, contemporary achieving a leveling of the daily usage pattern. The economical evaluations are carried out considering four different electrochemical technologies: lithium-ion (li-ion), advanced lead-acid, sodium-sulphur (NaS) and flow batte…
A sustainability point of view on sheet metal forming operations: material wasting and energy consumption in incremental forming and stamping process…
2012
Abstract Sustainability and sustainable production is nowadays a wide research field due the urgency of reducing environmental burdens of industrial production. Sustainable manufacturing issues are widely investigated too. In particular, due to the relevance such issues assume for automotive and aeronautical industry, the investigation of sheet metal forming processes sustainability is worth studying and, within this research fields, a certain lack of knowledge is still present. Many studies have been presented concerning the evaluation and reduction of environmental burdens in manufacturing. In this paper, the authors focus on sheet metal forming and aim to investigate both the efficient u…
Aggregated Packet Transmission in Duty-Cycled WSNs: Modeling and Performance Evaluation
2017
[EN] Duty cycling (DC) is a popular technique for energy conservation in wireless sensor networks (WSNs) that allows nodes to wake up and sleep periodically. Typically, a single-packet transmission (SPT) occurs per cycle, leading to possibly long delay. With aggregated packet transmission (APT), nodes transmit a batch of packets in a single cycle. The potential benefits brought by an APT scheme include shorter delay, higher throughput, and higher energy efficiency. In the literature, different analytical models have been proposed to evaluate the performance of SPT schemes. However, no analytical models for the APT mode on synchronous DC medium access control (MAC) mechanisms exist. In this …
A PC-based wattmeter for accurate measurements in sinusoidal and distorted conditions: Setup and experimental characterization
2012
This paper presents the development of a high-accuracy sampling wattmeter, which can be employed with both sinusoidal and distorted input signals. The proposed personal computer (PC)-based system is a simple, portable, and low-cost solution because it is based on two commercial data acquisition boards connected to a common PC. Owing to this solution, the voltage is sensed directly, avoiding expensive voltage dividers, while the current is sensed by means of a noninductive current shunt. Commercial software is also used for data processing and implementation of the virtual instrument. The setup of the PC-based wattmeter is described, with a detailed description of the correction strategy of …