Search results for "Operation"
showing 10 items of 2969 documents
Understanding the separation of anion mixtures by TiO2 membranes: Numerical investigation and effect of alkaline treatment on physicochemical propert…
2019
Abstract Mechanisms governing the rejection of ions from multi-ionic solutions, and especially the selectivity between various anions are not fully understood at the present time. In this study, it is proposed, in a first part, to investigate the evolution of electric and dielectric exclusion mechanisms when anions are mixed in a solution. For this purpose, the volumetric membrane charge Xd and the dielectric constant of the solution confined within pores ep are numerically assessed from rejection curves with a classic transport model. This study highlights that the rejection of the various anions is differently governed by electric and dielectric mechanisms but their contribution to mixtur…
Special issue of Computers and Operations Research: GRASP with Path Relinking: Developments and applications
2013
Assessing the Performance of Interactive Multiobjective Optimization Methods
2021
Interactive methods are useful decision-making tools for multiobjective optimization problems, because they allow a decision-maker to provide her/his preference information iteratively in a comfortable way at the same time as (s)he learns about all different aspects of the problem. A wide variety of interactive methods is nowadays available, and they differ from each other in both technical aspects and type of preference information employed. Therefore, assessing the performance of interactive methods can help users to choose the most appropriate one for a given problem. This is a challenging task, which has been tackled from different perspectives in the published literature. We present a …
Scheduling projects with limited number of preemptions
2009
A recent paper (Ballestin F, Valls V, Quintanilla S. Preemption in resource-constrained project scheduling. European Journal of Operational Research 2008;189:1136-152) revealed the potential benefits of allowing one interruption when scheduling activities in a resource-constrained project. This paper further investigates the effect of interruption on project length in more general cases. To achieve this, a new model that covers most practical applications of discrete activity preemption is proposed and a metaheuristic algorithm for the problem is developed. Computational experiments on the standard j120 and j30 sets generated using ProGen study the difference in makespan between allowing m …
Bootstrapping profit change: An application to Spanish banks
2012
The aim of this study is to provide a tool which enables us to conduct statistical analysis in the context of changes in productivity and profit. We build on previous initiatives to decompose profit change into mutually exclusive and exhaustive sources. To do this we use distance functions, which are calculated empirically using linear programming techniques. However, we may not learn a great deal by solving these linear programs unless methods of statistical analysis are used to examine the properties of the relevant estimators. Our purpose is to provide a methodology based on bootstrap that allows us to conduct statistical inference for the profit change decomposition. Thus, it will be po…
Relative risk estimation of dengue disease at small spatial scale
2017
Abstract Background Dengue is a high incidence arboviral disease in tropical countries around the world. Colombia is an endemic country due to the favourable environmental conditions for vector survival and spread. Dengue surveillance in Colombia is based in passive notification of cases, supporting monitoring, prediction, risk factor identification and intervention measures. Even though the surveillance network works adequately, disease mapping techniques currently developed and employed for many health problems are not widely applied. We select the Colombian city of Bucaramanga to apply Bayesian areal disease mapping models, testing the challenges and difficulties of the approach. Methods…
Energy Efficient Scheduling in Content Distribution Collaborative Mobile Clusters
2020
Most of the existing literatures on green communications aimed to improve the energy efficiency at the base station or data server. However, in order to fully experience high rate broadband multimedia services, prolonging the battery life of user equipment is also critical for the mobile terminals, especially for the smartphone users. In this work, we investigate the problem of designing a content distribution mobile platform named collaborative mobile clusters (CMC) via user cooperation to reduce the energy consumption at the terminal side. Specifically, given numbers of users interested in downloading a common content from the operator, both centralized and distributed user grouping and s…
Managing information security risks during new technology adoption
2012
Author's version of an article in the journal: Computers and Security. Also available from the publisher at: http://dx.doi.org/10.1016/j.cose.2012.09.001 In the present study, we draw on previous system dynamics research on operational transition and change of vulnerability to investigate the role of incident response capability in controlling the severity of incidents during the adoption of new technology. Toward this end, we build a system dynamics model using the Norwegian Oil and Gas Industry as the context. The Norwegian Oil and Gas Industry has started to adopt new information communication technology to connect its offshore platforms, onshore control centers, and suppliers. In oil co…
Fake news on Facebook and their impact on supply chain disruption during COVID-19
2022
AbstractSocial media (SM) fake news has become a serious concern especially during COVID-19. In this study, we develop a research model to investigate to what extent SM fake news contributes to supply chain disruption (SCD), and what are the different SM affordances that contribute to SM fake news. To test the derived hypotheses with survey data, we have applied partial least square based structural equation modelling (PLS-SEM) technique. Further, to identify how different configurations of SC resilience (SCR) capabilities reduce SCD, we have used fuzzy set qualitative comparative analysis (fsQCA). The results show that SM affordances lead to fake news, which increases consumer panic buying…
Das Dualproblem in der linearen Planungsrechnung
1959
Der folgende Beitrag zeigt den okonomischen Hintergrund des mathematischen Problems der Dualitat. Es werden das Beispiel eines Primal- und des zugehorigen Dualproblems sowie die allgemeinen Eigenschaften der Dualitat behandelt. Wahrend die Losung der ursprunglichen Aufgabe eine optimale Ausnutzung der vorhandenen Betriebskapazitaten im Hinblick auf den erreichbaren Maximalgewinn anstrebte, werden durch die Losung des Dualproblems diesen einzelnen Kapazitaten, dem Grade ihrer Knappheit entsprechend, bestimmte Werte zugerechnet. Aus diesen Werten konnen wertvolle Hinweise fur die Kapazitatsplanung gewonnen werden.