Search results for "Operations Research"
showing 10 items of 1297 documents
Online topology estimation for vector autoregressive processes in data networks
2017
An important problem in data sciences pertains to inferring causal interactions among a collection of time series. Upon modeling these as a vector autoregressive (VAR) process, this paper deals with estimating the model parameters to identify the underlying causality graph. To exploit the sparse connectivity of causality graphs, the proposed estimators minimize a group-Lasso regularized functional. To cope with real-time applications, big data setups, and possibly time-varying topologies, two online algorithms are presented to recover the sparse coefficients when observations are received sequentially. The proposed algorithms are inspired by the classic recursive least squares (RLS) algorit…
Recent Developments in Heterogeneous Photoreactor Modelling
1991
A selection of recently proposed heterogeneous photoreactors is presented. In some cases efforts have been made for the formulation of models able to describe the photoreactor behaviour with regard to the absorption of radiation. Examples of proposals of both novel photoreactor and models are critically reviewed.
An exact algorithm for preventive maintenance planning of series-parallel systems
2009
Reliability is a meaningful parameter in assessing the performance of systems such as chemical processing facilities, power plant, aircrafts, ships, etc. In the literature, reliability optimization is widely considered during the system design phase and it is carried out by an opportune selection of both system components and redundancy. On the other hand, the problem of maintaining a required level of reliability by an opportune maintenance policy has been poorly examined. The paper tackles this problem for a system whose major components can be maintained only during a planned system downtime. An exact algorithm is proposed in order to single out the set of components that must be maintai…
Integrated Production and Predictive Maintenance Planning based on Prognostic Information
2019
International audience; This paper address the problem of scheduling production and maintenance operation in predictive maintenance context. It proposes a contribution in the decision making phase of the prognostic and health management framework. Theprognostics and decision processes are merged and an ant colony optimization approach for finding the sequence of decisions that optimizes the benefits of a production system is developed. A case study on a single machine composed of several components where machine can have several usage profiles. The results show thatour approach surpasses classical condition based maintenance policy.
Performance-based research funding: Evidence from the largest natural experiment worldwide
2023
A performance-based research funding system (PRFS) is a nationwide incentive scheme that promotes and rewards university research performance through competition for government funding. The UK’s PRFS, currently the Research Excellence Framework (REF), is considered the oldest, largest and most developed payment-by-results system in academia worldwide. Surprisingly, and despite the strong criticisms, little has been done to quantitatively and casually evaluate the intended and unintended effects of the PRFSs. In this paper, we evaluate the incremental impact of the REF 2014 in the fields of Economics and Business. We use a synthetic control method to compare the performance of UK universitie…
Innovative Research Design – A Journey into the Information Typhoon
2014
Abstract Disasters are often characterized by their sudden onset and complex nature. The need for innovative and trans-disciplinary research that starts from the practice of disaster response is uncontested. Yet, the realities of field research require a rework of research design and processes. In the aftermath of Typhoon Haiyan that hit the Philippines in November 2013, a small team of researchers with different backgrounds came together in an innovative setting to investigate information management for decision support and sensemaking in the field. We combined the research in the field with remote support for logistics, communication and spot analyses. This letter describes our findings i…
Dimensions of scientific collaboration and its contribution to the academic research groups´ scientific quality
2009
11 pages, 3 tables, 3 figures
On the Influence of the Evaluation Methods in Conjoint Design — Some Empirical Results
2000
It is the goal of conjoint analysis to explain and predict preferences of customers (Schweikl 1985). Variants of predefined manifestations of attributes of various product concepts (both real and hypothetical) are created, and these are presented to test persons for evaluation. The contributions (partial benefits) the various attributes make to overall preference (overall benefit) are estimated on the basis of overall preference judgments (Green and Srinivasan 1978).
Competitive advantage and strategy formulation
2005
Purpose – The aim of this paper is to promote the use of dynamic capabilities as a strategic tool of the highest order in terms of firm management.Design/methodology/approach – The content of the article is developed from a table that offers some insights into the relationship between the three theoretical perspectives analyzed in the paper: resource‐based view, knowledge‐based view and dynamic‐capabilities view.Findings – The paper describes the evolution that can be discerned in the process of developing competitive advantage, from a resource‐based view to a dynamic‐capabilities framework.Originality/value – The objective of the article was not to bring to light any new revelations in thi…
The contribution of dynamic marketing capabilities to service innovation and performance
2015
Innovation can become a sustainable competitive advantage for service firms. However, there is lack of empirical research on how marketing capabilities support innovation. This study differentiates between operational and dynamic marketing capabilities, the latter related to strategic marketing, marketing planning and market knowledge skills. Based on a sample of 152 service firms, the results show that operational marketing capabilities influence on those dynamic marketing capabilities. Strategic marketing and marketing planning capabilities impact positively on firm's performance while market knowledge capabilities impact positively on service innovation.