Search results for "Operations"
showing 10 items of 1692 documents
A survey on IVIVC/IVIVR development in the pharmaceutical industry – Past experience and current perspectives
2017
The present work aimed to describe the current status of IVIVC/IVIVR development in the pharmaceutical industry, focusing on the use and perception of specific approaches as well as successful and failed case studies. Two questionnaires have been distributed to 13 EFPIA partners of the Oral Biopharmaceutics Tools Initiative and to the Pharmacokinetics Working Party of the European Medicines Agency in order to capture the perspectives and experiences of industry scientists and agency members, respectively. Responses from ten companies and three European Agencies were received between May 21st 2014 and January 19th 2016. The majority of the companies acknowledged the importance of IVIVC/IVIVR…
A Branch-and-Cut method for the Capacitated Location-Routing Problem
2011
International audience; Recent researches in the design of logistic networks have shown that the overall distribution cost may be excessive if routing decisions are ignored when locating depots. The Location-Routing Problem (LRP) overcomes this drawback by simultaneously tackling location and routing decisions. The aim of this paper is to propose an exact approach based on a Branch-and-Cut algorithm for solving the LRP with capacity constraints on depots and vehicles. The proposed method is based on a zero-one linear model strengthened by new families of valid inequalities. The computational evaluation on three sets of instances (34 instances in total), with 5–10 potential depots and 20–88 …
Swing options in commodity markets: a multidimensional Lévy diffusion model
2013
Author's version of an article in the journal: Mathematical Methods of Operations Research. Also available from the publisher at: http://dx.doi.org/10.1007/s00186-013-0452-7 We study valuation of swing options on commodity markets when the commodity prices are driven by multiple factors. The factors are modeled as diffusion processes driven by a multidimensional Lévy process. We set up a valuation model in terms of a dynamic programming problem where the option can be exercised continuously in time. Here, the number of swing rights is given by a total volume constraint. We analyze some general properties of the model and study the solution by analyzing the associated HJB-equation. Furthermo…
A computational study of LP-based heuristic algorithms for two-dimensional guillotine cutting stock problems
2002
In this paper we develop and compare several heuristic methods for solving the general two-dimensional cutting stock problem. We follow the Gilmore-Gomory column generation scheme in which at each iteration a new cutting pattern is obtained as the solution of a subproblem on one stock sheet. For solving this subproblem, in addition to classical dynamic programming, we have developed three heuristic procedures of increasing complexity, based on GRASP and Tabu Search techniques, producing solutions differing in quality and in time requirements. In order to obtain integer solutions from the fractional solutions of the Gilmore-Gomory process, we compare three rounding procedures, rounding up, t…
Comprensión de textos expositivos académicos en e-book Reader y en papel: influencia del conocimiento previo de dominio y la aptitud verbal
2018
espanolResumen: En un estudio del que participaron 102 estudiantes universitarios, se comparo la comprension en la lectura de textos expositivos academicos impresos versus en formato de e-book Reader. Se examinaron los efectos del soporte, del conocimiento especifico de dominio previo del lector y la aptitud verbal. Asimismo se indagaron las actitudes de los estudiantes hacia los soportes textuales antes y despues de la experiencia. Los resultados sugieren que el e-book Reader beneficiaria a los lectores competentes, y/o que podria promover mayor actividad metacognitiva en los procesos de comprension. Asimismo, las opiniones hacia el e-book Reader cambiaron despues de la experiencia, aunque…
EMISSION FACTORS, VEHICLE MODAL ACTIVITY AND ROAD OPERATIONS. A MESOSCOPIC APPROACH
2009
Current studies underline that vehicle emissions are highly linked to modal vehicle activity and a modal approach to traffic-related air quality modeling is suitable to estimate mobile source contribution to air quality. Pollutant emissions depend on characteristics of vehicles in traffic flow and on road operating conditions predictable after the implementation of the road project; then, the usual emission rate models do not predict properly the on-road vehicles emissions of modal traffic events, such as those ones occurring at intersections. Moreover modal activity analysis carried out at micro scale level, as required by modal emission models, will be still necessary to value reliable em…
Assessing the dynamic of agri-food export trends before and after the EU Eastern Enlargement
2018
This study examines the evolution in development of Intra-European Union agri-food export during the period 2000–2011. By using Data Envelopment Window Analysis, this paper at first provides a more comprehensive picture on agri-food trade performance of sampled New Member States, focusing the attention on the pre and post phase of the enlargement process. Two specific country case studies will be released, revealing different patterns of performance among New EU Member States. The majority of New EU Member States differed in their approach in benefiting from the opportunity to enter into the EU enlarged market, and some of theme preferred to strengthen established trade relations with a pas…
HABILIDADES MATEMÁTICAS INICIALES Y DIFICULTADES MATEMÁTICAS PERSISTENTES
2017
Abstract.INITIAL MATH SKILLS AND PERSISTENT MATH DIFFICULTIESThe aim of the present study was to analyse the differences in certain basic mathematical competences (for example, counting, logical operations, magnitude comparability skills) assessed in. Early Childhood Education between children with persistent difficulties in the area of mathematics in 2nd Primary Education and children with adequate performance. The final sample of the study consisted of 180 children (composed initially of 209 pre-schoolers), of which 6.6% showed persistent mathematics difficulties (n = 12) and 45.5% presented an adequate performance in both measurements (n = 82). In Early Childhood Education we administere…
Flexibly scheduled early childhood education and care: experiences of Finnish parents and educators
2017
This study focuses on flexibly scheduled early childhood education and care (ECEC), an institutional childcare service for Finnish families where both parents, or a single parent, work non-standard hours. Although many countries nowadays offer extended hours day care, only Finland has a publicly provided, law-based system guaranteeing ECEC during non-standard as well as standard hours. We explore, drawing on parental survey data, what kinds of families use such services and when. Furthermore, we utilise web-survey data obtained from early educators to find out what they report as the main challenges involved in implementing flexibly scheduled ECEC. The results showed that single-parent fami…
Reflections on the Hohmann Transfer
2004
Walter Hohmann was a civil engineer who studied orbital maneuvers in his spare time. In 1925, he published an important book (Ref. 1) containing his main result, namely, that the most economical transfer from a circular orbit to another circular orbit is achieved via an elliptical trajectory bitangent to the terminal orbits. With the advent of the space program some three decades later, the Hohmann transfer maneuver became the most fundamental maneuver in space. In this work, we present a complete study of the Hohmann transfer maneuver. After revisiting its known properties, we present a number of supplementary properties which are essential to the qualitative understanding of the maneuver.…