Search results for "Operations"
showing 10 items of 1692 documents
Variation Mode and Effect Analysis: a Practical Tool for Quality Improvement
2006
This paper describes a statistically based engineering method, variation mode and effect analysis (VMEA), that facilitates an understanding of variation and highlights the product/process areas in which improvement efforts should be targeted. An industrial application is also described to illustrate how the VMEA can be used for quality improvement purposes. Copyright © 2006 John Wiley & Sons, Ltd.
Stationary battery technologies in the U.S.: Development Trends and prospects
2017
Abstract In the last years, stationary battery systems started to attract the attention of stakeholders thanks to their unique ability to decouple power generation and load over time, providing the ancillary services necessary for the stability and the reliability of the electrical system. This is especially true in the presence of high levels of penetration of renewable energy technologies, like wind and solar photovoltaic (PV), because of increased fluctuations in the electricity produced by these renewable sources. Despite the growing interest in energy storage technologies, the academic literature has not completely assessed the development trends of this sector. In order to fill this g…
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.