Search results for "Operations Research"
showing 10 items of 1297 documents
Analysis and design of sequencing rules for car sequencing
2009
Abstract This paper presents novel approaches for generating sequencing rules for the car sequencing (CS) problem in cases of two and multiple processing times per station. The CS problem decides on the succession of different car models launched down a mixed-model assembly line. It aims to avoid work overloads at the stations of the line by applying so-called sequencing rules, which restrict the maximum occurrence of labor-intensive options in a subsequence of a certain length. Thus to successfully avoid work overloads, suitable sequencing rules are essential. The paper shows that the only existing rule generation approach leads to sequencing rules which misclassify feasible sequences. We …
DEA-like models for efficiency evaluation of specialized and interdependent units
2001
Abstract The problem of evaluating the efficiency of a set of specialized and interdependent decision making subunits (DMSUs) that make up a larger decision making unit (DMU) is considered. The DMSUs are interdependent, in the sense that part of the output produced by each of them may be used as an input by the other ones. They are also specialized, hence non-homogeneous, as they may have not the same inputs and outputs. For this problem, some efficiency indexes are introduced, and they are shown to satisfy some basic properties.
Efficiency analysis in banking firms: An international comparison
1997
The intensive process of financial European integration, together with the profound transformation and deregulation that has taken place in the Spanish Banking System, justifies the evaluation of its efficiency in comparison with that of other banking systems. In this context, the aim of this study is to analyze the productivity, efficiency and differences in technology of several banking systems. Using a non-parametric approach together with the Malmquist index, we compare the efficiency, productivity and differences in technology of different European and US banking systems for the year 1992. Finally, for a subsample of banks belonging to the same group of countries, using real as opposed…
The expected value of the traceability information
2015
Abstract Recent regulations on agri-food traceability prescribe traceability throughout the entire supply chain, in order to ensure consumers’ safety and product quality. This has led producers and retailers to consider the opportunity to improve the firm's reputation and consumer confidence through the implementation of traceability systems designed not only to satisfy the legal requirements, but also to track the quality of the products through the supply chain for optimization purposes. However the actual implementation of such systems depends on the possibility of gathering specific information related to the product quality. Nowadays, innovative and non invasive technologies such as th…
A survey of variants and extensions of the location-routing problem
2015
This is a review of the literature on variants and extensions of the standard location-routing problem published since the last survey, by Nagy and Salhi, appeared in 2006. We propose a classification of problem variants, provide concise paper excerpts that convey the central ideas of each work, discuss recent developments in the field, and list promising topics for further research.
A real options game of alliance timing decisions in biopharmaceutical research and development
2017
Abstract In this article we examine the alliance timing trade-off facing both pharmaceutical and biotech firms in a stochastic and competitive environment. Specifically, we introduce a real options game (ROG), where a pharmaceutical company can choose between two competing biotech firms by sequentially offering a licensing deal early or late in the new drug development process. We find that, when the alliance raises the drug market value significantly, the agreement is signed late in the drug development process. This suggests that the postponement effect implied by the use of real options prevails over the biotech firms’ competition effect, which would instead play in favor of an early agr…
The Hierarchical Mixed Rural Postman Problem: Polyhedral analysis and a branch-and-cut algorithm
2017
[EN] The Hierarchical Mixed Rural Postman Problem is defined on a mixed graph where arcs and edges that require a service are divided into clusters' that have to be serviced in a hierarchical order. The problem generalizes the Mixed Rural Postman Problem and thus is NP-hard. In this paper, we provide a polyhedral analysis of the problem and propose a branch-and-cut algorithm for its solution based on the introduced classes of valid inequalities. Extensive computational experiments are reported on benchmark instances. The exact approach allows to find the optimal solutions in less than 1 hour for instances with up to 999 vertices, 2678 links, and five clusters.
Navigating uncharted waters: Designing business models for virtual and augmented reality companies in the medical industry
2021
Abstract New technologies are at the heart of industry transformation. Virtual and augmented reality companies provide fundamentally new ways of communication, treatment, education, and specialist training within the medical industry. However, business models for new ventures that target the medical industry have received scant attention within academic research. Using a multiple case study approach, we analyze how virtual and augmented reality firms create value for their customers in the medical industry. In all, we have studied eight companies that offer different types of solutions for their target segments. The results of the analysis are four design elements consisting of twelve posit…
Bundle generation for last-mile delivery with occasional drivers
2022
In this paper, we present the vehicle routing problem (VRP) with occasional drivers (OD) and order bundles (OB). The problem VRP-OD-OB is an extension of the VRP-OD, where instead of assigning one customer per driver, drivers are assigned bundles of customers. To deal with the bundle-to-driver assignment, a bidding system is exploited, in which a company offers a set of bundles and the drivers raise their bids. These bids depend on features such as the drivers’ destination, flexibility in deviating from the shortest path, and willingness to offer service. To generate valuable bundles of customers, we propose two strategies: (i) an innovative approach based on the creation of corridors, and …
Modelling and forecasting mortality in Spain
2008
[EN] Experience shows that static life tables overestimate death probabilities. As a consequence of this overestimation the premiums for annuities, pensions and life insurance are not what they actually should be, with negative effects for insurance companies or policy-holders. The reason for this overestimation is that static life tables, through being computed for a specific period of time, cannot take into account the decreasing mortality trend over time. Dynamic life tables overcome this problem by incorporating the influence of the calendar when graduating mortality. Recent papers on the topic look for the development of new methods to deal with this dynamism. Most methods used in dyna…