Search results for "STRATEGY"
showing 10 items of 2256 documents
On the importance of perspective and flexibility for efficiency measurement: effects on the ranking of decision-making units
2017
[EN] The efficiency of a firm can be assessed from several perspectives and using a variety of methodologies. Data envelopment analysis (DEA) is one of the most commonly used methodologies. Conventional DEA analyses or models allow one to classify decision-making units (DMUs) into efficient and inefficient ones based on their efficiency scores, which could also be used for ranking DMUs; however, such rankings generally show many ties. Super-efficiency DEA analyses have been proposed to address the tie issue. On the other hand, conventional DEA analyses only take account of a single perspective in estimating efficiency scores. Cross-efficiency DEA analyses provide an alternative that takes a…
Opportunities and pitfalls related to e-commerce strategies in small-medium firms: A system dynamics approach
2002
E-commerce is often perceived as a powerful lever to foster growth of SMEs. However, both the literature and empirical evidence have shown the perils hidden in superficial decision making by SME entrepreneurs. A system dynamics (SD) approach is used in this article to demonstrate how managing processes of accumulation and depletion of strategic assets, detecting inertial effects of decisions made in the past, and selectively acting on policy levers are likely to help entrepreneurs in understanding opportunities and pitfalls related to e-commerce strategies. A feedback analysis of three case studies selected from the literature and the main findings from a survey conducted by the authors on …
Base-isolated structure equipped with tuned liquid column damper: An experimental study
2019
Abstract In this study, a novel passive vibration control strategy is investigated experimentally, where a Tuned Liquid Column Damper protects a base-isolated structure. The Tuned Liquid Column Damper is attached to the base, in contrast to typical attachment points of passive energy dissipation devices in high-rise buildings at elevated levels. Experiments on a base-excited small-scale three-story shear frame are conducted in order to study effects of both control devices – base-isolation and Tuned Liquid Column Damper – on the structural model. The dynamic properties of the stand-alone shear frame and the base-isolation subsystem are derived using standard dynamic test methods based on di…
Optimal design of complex passive-damping systems for vibration control of large structures: An energy-to-peak approach
2014
Published version of an article in the journal: Abstract and Applied Analysis. Also available from the publisher at: http://dx.doi.org/10.1155/2014/510236 Open Access We present a new design strategy that makes it possible to synthesize decentralized output-feedback controllers by solving two successive optimization problems with linear matrix inequality (LMI) constraints. In the initial LMI optimization problem, two auxiliary elements are computed: a standard state-feedback controller, which can be taken as a reference in the performance assessment, and a matrix that facilitates a proper definition of the main LMI optimization problem. Next, by solving the second optimization problem, the …
An original multi-objective criterion for the design of small-scale polygeneration systems based on realistic operating conditions
2008
The optimal design and operation of cogeneration and trigeneration systems for buildings applications is a complex issue, which has been investigated by several different approaches. Both the two basic management strategies, namely heat-tracking and electricity-tracking, have advantages and drawbacks in terms of operating results and may lead the plant designer either to undersize or oversize the CHP unit with respect to the optimal lay-out. Experimental works have demonstrated how the actual on-site performance of small-scale polygeneration systems significantly differs from their expected operation, due to the need for a regular plant operation and the effects of outages for scheduled or …
Shakedown optimal design of reinforced concrete structures by evolution strategies
2000
Approaches the shakedown optimal design of reinforced concrete (RC) structures, subjected to variable and repeated external quasi‐static actions which may generate the well‐known shakedown or adaptation phenomenon, when constraints are imposed on deflection and/or deformation parameters, in order to simulate the limited flexural ductility of the material, in the presence of combined axial stress and bending. Within this context, the classical shakedown optimal design problem is revisited, using a weak upper bound theorem on the effective plastic deformations. For this problem a new computational algorithm, termed evolution strategy, is herein presented. This algorithm, derived from analogy …
Multiple-criteria cash-management policies with particular liquidity terms
2019
Abstract Eliciting policies for cash management systems with multiple assets is by no means straightforward. Both the particular relationship between alternative assets and time delays from control decisions to availability of cash introduce additional difficulties. Here we propose a cash management model to derive short-term finance policies when considering multiple assets with different expected returns and particular liquidity terms for each alternative asset. In order to deal with the inherent uncertainty about the near future introduced by cash flows, we use forecasts as a key input to the model. We express uncertainty as lack of predictive accuracy and we derive a deterministic equiv…
AN OBJECT ORIENTED MODEL FOR SCHEDULING IN AGILE MANUFACTURING
2002
Agility represents a key factor in industry to handle the continuous market changes. Companies must re-organize their activities to be agile and competitive in such a dynamic environment. In particular, production planning and control tools are very important to optimize the manufacturing process responsiveness to sudden changes in customer demand. In this paper, an attempt has been made to develop an object-oriented software architecture that allows the optimal line organization to be determined once a set of parts to be produced has been ordered. An optimization module represented by a simulated annealing algorithm has been interfaced with an object oriented architecture to build up a fr…
Evolutionary algorithm for fiber laser in ultrashort pulse regime
2016
This thesis deals with the generation of ultrashort pulses within a fiber laser cavity through the automatic optimization of its parameters by an evolutionary algorithm. The interest of this subject comes from the difficulty to systematically explore dynamics in a large domain of experimental parameters. We have shown that it is possible to implement an evolutionary algorithm on fiber laser cavity with appropriate precautions. We have experimentally demonstrated for the first time the mode locking of a laser cavity only using the optimization of polarization controllers through an automatic and self-learning procedure. We also have demonstrated that selecting the mode locking from it radio-…
The chemical composition of the floral extract of Epipogium Aphyllum sw. (Orchidaceae): A cluefor thier pollination biology
2014
Epipogium aphyllum is a rare European obligate mycoheterotrophic orchid lacking chlorophyll. It has not been studied previously with respect to pollination biology. We studied the association between the composition of floral scent emission and its pollination systems. Field observation indicates that the main pollinators of Epipogium aphyllum are representatives of the genus Bombus (Hymenoptera), B. lucorum, B. hortorum, B. terrestris, B. pascuorum and B. proteus, and the genus Apis (Hymenoptera) namely A. mellifera. The main potential vector (observed to accidentally carry pollen), is most likely Episyrphus balteatus (Diptera, Syrphidae). The chemical composition of the floral extracts of…