Search results for "Operation"
showing 10 items of 2969 documents
Life cycle assessment of a solar thermal collector: sensitivity analysis, energy and environmental balances
2005
Abstract Starting from the results of a life cycle assessment of solar thermal collector for sanitary warm water, an energy balance between the employed energy during the collector life cycle and the energy saved thanks to the collector use has been investigated. A sensitivity analysis for estimating the effects of the chosen methods and data on the outcome of the study was carried out. Uncertainties due to the eco-profile of input materials and the initial assumptions have been analysed. Since the study is concerned with a renewable energy system, attention has been focused on the energy indexes and in particular the “global energy consumption”. Following the principles of Kyoto Protocol, …
Exploring the uncertainty in capacity estimation at roundabouts
2017
Abstract Purpose In gap-acceptance theory the critical and the follow-up headways have a significant role in determining roundabout entry capacities which in turn depend on circulating flow rates under a specified arrival headway distribution. Calculation considers single mean values of the gap-acceptance parameters, neglecting the inherent variations in these random variables and providing a single value of entry capacity. The purpose of this paper is to derive the entry capacity distribution which accounts for the variations of the contributing (random) variables and suggest how to consider this issue in the operational analysis of the roundabouts. Methods We performed a Monte Carlo simul…
A combined multi-criteria approach to support FMECA analyses: A real-world case
2018
[EN] The paper proposes an approach that combines reliability analyses and multi-criteria decision methods to optimize maintenance activities of complex systems. A failure mode, effects, and criticality analysts (FMECA) is initially performed and the fuzzy TOPSIS (FTOPSIS) method is then applied to rank previously identified failure modes. For prioritization, failure modes are assessed against three evaluation criteria that differ from those traditionally involved in risk priority number (RPN) computation (i.e. severity, occurrence and detection). Two criteria refer to the maintenance management reflecting the operational time taken by the maintenance activity performed after the occurrence…
Exploring the Potential and the Boundaries of the Rolling Horizon Technique for the Management of Reservoir Systems with over-Year Behaviour
2016
The paper presents a set of experiments on the Rolling Horizon Technique (RHT), applied to the management of a multi-reservoir, multipurpose water resources system with over-year behaviour. In the RHT, decisions on releases from reservoirs are taken for a number of time steps ahead (the Forecasting Horizon – FH) through an optimization model, based on the present water availability in reservoirs and on some forecasts of future inflows over the FH. Only the decision concerning the first time step (the current month) is then implemented, as new information on reservoir levels and forecasts becomes available so that the process can start again with updated information. The paper investigates h…
Energy certification of buildings: A comparative analysis of progress towards implementation in European countries
2010
Abstract The Energy Performance Building Directive (Directive 2002/91/EC) introduced the compulsory energy certification of buildings in the EU from 2006 and it has played a key role in the common policy to monitor and reduce energy consumption. In order to assess the experience gained in this field in Europe overall, and in particular against the highly diverse settings of the different European nations, this paper examines the extent to which the Directive has been implemented by the 27 EU Member States. This is done via a comparative analysis assisted by two different indicators: of uniformity and of excellence. The measure of uniformity makes it possible to assess the degree of harmony …
Sensitivity analysis to quantify uncertainty in Life Cycle Assessment: The case study of an Italian tile
2011
Abstract The results of a Life Cycle Assessment (LCA) study can be affected by several uncertainty sources, mainly due to the methodological choices, the initial assumptions, i.e. allocation rules, system boundaries and impact assessment methods, and the quality of the available data. Then, the experts should estimate the extent of the above-mentioned sources of uncertainty for improving the reliability and the representativeness of the obtained eco-profiles. To estimate the uncertainty is necessary to obtain reliable, transparent and representative LCA results and to correctly support decision-makers in the selection of different product or process options. The following paper starts from …
Analyzing the Current Phase of the OSS/BSS Software Market
2009
In this section, the evolution of the OSS/BSS software industry is described, and the current phase of the OSS/BSS software market is analyzed using quantitative data. The first analysis uses the viewpoint of the general industry lifecycle stage models. This is followed by an analysis from the viewpoint of the vertical software market evolution model. The last section analyses the mergers and acquisitions of the OSS/BSS market from the last few years.
Theories Related to Vertical Software Industry Evolution
2009
The word innovation often refers to a new product, usually to an industrial or technical invention, although actually all kinds of new ideas should be considered. Following Rogers (2003, p. 12), “[a]n innovation is an idea, practice, or object that is perceived as new by an individual or other unit of adoption.” The birth of a new industry can be considered to occur as this new innovation is introduced to the markets by the first manufacturing firm. At this point the potential customers evaluate whether it is worth to adopt the product or not.
ORDINAL MEASUREMENTS WITH INTERVAL CONSTRAINTS IN THE EIA PROCESS FOR SITING A WASTE STORAGE AREA
2009
We describe application of multicriteria decision analysis (MCDA) in the Environmental Impact Assessment (EIA) procedure for siting a waste storage area. The world’s largest biofuel-based combined heat and power (CHP) plant was built in Pietarsaari, Finland. The plant produces certain byproducts, such as flue dust and bottom ash, which need to be processed and stored to prevent releases to the environment. Different storage sites will have different impacts on people, nature, and the economy. Cardinal measurement of the different impacts was considered too costly. Instead, ordinal measurement of all criteria was applied; i.e., experts ranked the alternative storage sites according to each c…
Co2 emissions of French shippers: The roles of delivery frequency and weight, mode choice, and distance
2014
In this article, the authors describe the effects of delivery frequency, mode choice, distance, and shipment weight on the CO₂ emissions of French shippers, taking advantage of a 2004 survey of French shippers (ECHO) which describes the characteristics of 3000 shippers, 10,000 shipments, and 20,000 transport chain legs. Once the energy consumption and CO₂ emissions of every shipment have been computed, they are divided by the corresponding number of ton-kilometers in order to find their carbon intensity (in grams of CO₂ per ton-kilometer). The authors then analyze the latter with respect to a number of selected shipment characteristics: shipment frequency and mode choice (planning choices),…