Search results for " Opera"
showing 10 items of 3606 documents
Solutions properties and solute–solvent interactions in ternary sugar–salt–water solutions
2010
International audience; Viscometric constants were used to provide information on solute-solvent interactions in ternary water-sugar-salt solutions. Comparison was made between pure water and aqueous salt solution as solvents affecting the behaviour of small carbohydrates. The determination of intrinsic viscosity was made more accurate by applying triple extrapolation of the three equations (Huggins. Kramer and Meffroy-Biget). Results obtained with this triple extrapolation method were compared to that obtained with the Jones-Dole equation usually used. The B coefficient of the Jones-Dole equation was interpreted in terms of its components (B(size)) and (B(structure)), respectively assigned…
On the Bullwhip Avoidance Phase: supply chain collaboration and order smoothing
2009
This paper provides an assessment of the impact of collaboration and smoothing replenishment rules on supply chain operational performance and customer service level. Three supply chain configurations (i.e. Traditional, Information Exchange and Synchronised) in which orders are generated by smoothing (S, R) inventory control policies are studied for different proportional controllers. A supply chain stress test is performed through a sudden and intense change in demand. A structured and extended supply chain assessment framework is adopted. The main conclusions of this paper are the following. (i) The impact of Supply Chain Collaboration on overall supply chain performance is greater than t…
Robust optimality of linear saturated control in uncertain linear network flows
2008
We propose a novel approach that, given a linear saturated feedback control policy, asks for the objective function that makes robust optimal such a policy. The approach is specialized to a linear network flow system with unknown but bounded demand and politopic bounds on controlled flows. All results are derived via the Hamilton-Jacobi-Isaacs and viscosity theory.
ROBUST CONTROL STRATEGIES FOR MULTI—INVENTORY SYSTEMS WITH AVERAGE FLOW CONSTRAINTS
2006
Abstract In this paper we consider multi—inventory systems in presence of uncertain demand. We assume that i) demand is unknown but bounded in an assigned compact set and ii) the control inputs (controlled flows) are subject to assigned constraints. Given a long—term average demand, we select a nominal flow that feeds such a demand. In this context, we are interested in a control strategy that meets at each time all possible current demands and achieves the nominal flow in the average. We provide necessary and sufficient conditions for such a strategy to exist and we characterize the set of achievable flows. Such conditions are based on linear programming and thus they are constructive. In …
Inventory policies and information sharing in multi-echelon supply chains
2011
The aim of this article is to show how to modify a replenishment rule in relation to the operational information shared by suppliers. More specifically, we present a model of an Automatic Pipeline Variable Inventory and Order-Based Production Control System rule for a multi-echelon supply chain characterised by different increasing levels of shared information. A numerical study is presented to underline the performance differences for three variants of the smoothing order rule in terms of bullwhip reduction, inventory stability and operational and customer responsiveness. Results show how the effectiveness of a smoothing replenishment rule depends on the level of information sharing.
Formulations for an inventory routing problem
2014
In this paper, we present and compare formulations for the inventory routing problem (IRP) where the demand of customers has to be served, over a discrete time horizon, by capacitated vehicles starting and ending their routes at a depot. The objective of the IRP is the minimization of the sum of inventory and transportation costs. The formulations include known and new mathematical programming formulations. Valid inequalities are also presented. The formulations are tested on a large set of benchmark instances. One of the most significant conclusions is that the formulations that use vehicle-indexed variables are superior to the more compact, aggregate formulations.
La contabilidad como sistema de información para el control de la gestión social y ambiental de las empresas. Un estudio comparado de los casos exito…
2017
La presente investigación responde a criterios de oportunidad e interés desde el discurso sobre la gestión socialmente responsable y ambientalmente sostenible en el ámbito más amplio de las organizaciones, cuyo aspecto central, para la comprensión del fenómeno, se posiciona desde la contabilidad como sistema de información para el control de las externalidades generadas en el desarrollo de los negocios. La hipótesis central es qué la contabilidad, al capturar la realidad de la organización y ser el lenguaje del negocio permite articular variables para el análisis social y ambiental, como parte integral de la información financiera y no financiera. Lo anterior, además de responder a las diná…
The Hermitian part of a Rickart involution ring, I
2014
Rickart *-rings may be considered as a certain abstraction of the rings B(H) of bounded linear operators of a Hilbert space H. In 2006, S. Gudder introduced and studied a certain ordering (called the logical order) of self-adjoint Hilbert space operators; the set S(H) of these operators, which is a partial ring, may be called the Hermitian part of B(H). The new order has been further investigated also by other authors. In this first part of the paper, an abstract analogue of the logical order is studied on certain partial rings that approximate the Hermitian part of general *-rings; the special case of Rickart *-rings is postponed to the next part.
Capturing citizens — Emerging needs: Using social networks in smart cities
2017
In order to reach its objectives, smart cities (or whatever kind of smart urban environment) should be underpinned by complex cyber physical systems (CPS) able to discover needs and services and "smartly" combine them. Services may be thought as services offered by software components, of whatever nature, for instance software, bot, robot, app and so on. Searching for the best service depends on the need of the citizen(s) and also on the type of (smart) environment the citizens are in. Analysis and design of CPSs are more challenging than the only physical or the only cyber system. We propose a design paradigm shift towards runtime for identifying requirements of cyber physical systems for …
Combined inguinal hernia in the elderly. Portraying the progression of hernia disease
2016
Abstract Introduction Identification of a combined hernia is a common occurrence in the course of inguinal hernia repair. This type of protrusion disease seems to affect the elderly, in particular. Very few investigations have been carried out to ascertain the structural changes that occur in the groin affected by this clinical condition. Method Analysis of intraoperative findings of combined inguinal hernias evidenced in the elderly, from the most recent 100 groin hernia repair procedures carried out by a single operator, represents the basis of the article. Protrusions that presumably represent the forerunner of this type of hernia were also analyzed: double ipsilateral inguinal hernias c…