Articles scientifiques

A Context-Based Approach to Reconciling Data Interpretation Conflicts in Web Services Composition


ACM Transactions on Internet Technology

novembre 2013, vol. 13, n°1

Départements : Informations Systems and Operations Management, GREGHEC (CNRS)

Mots clés : Algorithms; Design; Languages; Standardization; Web services; composition; mediation; semantics; context

We present a comprehensive classification of data misinterpretation problems and develop an approach to automatic detection and reconciliation of data interpretation conflicts in Web services composition. The approach uses a lightweight ontology augmented with modifiers, contexts, and atomic conversions between the contexts. The WSDL descriptions of Web services are annotated to establish correspondences to the ontology. Given the naive Business Process Execution Language (BPEL) specification of the desired Web services composition with data interpretation conflicts, the approach can automatically detect the conflicts and produce the corresponding mediated BPEL. Finally, we develop a prototype to validate and evaluate the approach

Distributionally robust workforce scheduling in call centres with uncertain arrival rates

S. Liao, C. VAN DELFT, J. Vial

Optimization Methods and Software

juin 2013, vol. 28, n°3, pp.501-522

Départements : Informations Systems and Operations Management, GREGHEC (CNRS)

Mots clés : Call centres, Uncertain arrival rates, Robust optimization, Ambiguity, Staff-scheduling, Totally unimodular

Call centre scheduling aims to determine the workforce so as to meet target service levels. The service level depends on the mean rate of arrival calls, which fluctuates during the day, and from day to day. The staff schedule must adjust the workforce period per period during the day, but the flexibility in doing so is limited by the workforce organization by shifts. The challenge is to balance salary costs and possible failures to meet service levels. In this paper, we consider uncertain arrival rates, that vary according to an intra-day seasonality and a global busyness factor. Both factors (seasonal and global) are estimated from past data and are subject to errors. We propose an approach combining stochastic programming and distributionally robust optimization to minimize the total salary costs under service level constraints. The performance of the robust solution is simulated via Monte-Carlo techniques and compared to the solution based on pure stochastic programming

Exploring the Link between the Humanitarian Logistician and Training Needs

A. Allen, G. Kovács, A. MASINI, A. Vaillancourt, L. Van Wassenhove

Journal of Humanitarian Logistics and Supply Chain Management

octobre 2013, vol. 3, n°2, pp.129-148

Départements : Informations Systems and Operations Management, GREGHEC (CNRS)

Mots clés : Career path, Education, Humanitarian logistics, Logistics skills, Training

Purpose – The aim of this paper is to evaluate job profiles in humanitarian logistics, and assess current task priorities in light of further training and educational needs.Design/methodology/approach – The paper presents findings from a survey among humanitarian logistics practitioners and compares these to other studies in this area. It uses econometric models to evaluate the impact of managerial responsibilities in training needs, usage of time and previous training.Findings – The results show that the skills required in humanitarian logistics seem to follow the T-shaped skills model from Mangan and Christopher when looking at training wanted and time usage.Research limitations/implications – Survey respondents being members of the Humanitarian Logistics Association (HLA) may be more interested in developing the humanitarian logistics profession than other populations.Originality/value – This paper offers an insight in the specific skill requirements of humanitarian logisticians from members of the HLA and allows to understand which type of skills are linked to managerial responsibilities. The paper also establishes a link between logistics skill models and career progressions overall

Finding and Implementing Energy Efficiency Projects in Industrial Facilities

S. AFLAKI, P. Kleindorfer, V. Sáenz de Miera Polvorinos

Production and Operations Management

mai-juin 2013, vol. 22, n°3, pp.503-517

Départements : Informations Systems and Operations Management, GREGHEC (CNRS)

Mots clés : Sustainable operations, Energy efficiency, Kaizen, Carbon footprinting

This study addresses the challenges of finding and implementing profitable energy efficiency (EE) projects, a critical foundation for sustainable operations. We focus on manufacturing enterprises, but many of our findings apply also to the back office of service operations. Our starting point is that, in nearly every industrial enterprise, there are many profitable EE projects that could be implemented but are not. An oft-cited hindrance to implementation is the lack of an internal management framework in which to find, value, and execute these projects. Using a conceptual approach, we rely on proven sustainable operations tools to develop such a framework. We identify three major value drivers of EE projects: savings intensity, 'green' image, and project complexity. We then describe a framework for understanding the context of EE projects in industry, with an underlying analytic foundation in optimal portfolio analysis. A case study of a large manufacturing site is used to illustrate emerging best practices'based on Kaizen management principles'for integrating EE project management with operations, engineering, and strategy

Finite horizon stochastic inventory problem with dual sourcing: Near myopic and heuristics bounds

A. Cheaitou, C. VAN DELFT

International Journal of Production Economics

juin 2013, vol. 143, n°2, pp.371-378

Départements : Informations Systems and Operations Management, GREGHEC (CNRS)

Mots clés : Multi-periodic procurement planning, Inventory control, Slow and fast procurement modes, Myopic policies, Upper and lower bounds

We consider a class of multi-periodic non-stationary stochastic single-product inventory planning problems where two procurement modes can be used at each period: a first order with immediate delivery and a second order with a single-period delivery delay. Clearly, the slow delivery mode is less expensive than the fast. We develop a discounted backlog model, with non-stationary procurement, inventory holding and backlog penalty costs proportional to the ordered quantities, inventory levels and number of backlogged units respectively. The demands are defined as non-stationary and independent random variables. We partially characterize the optimal ordering policy structure and we develop theoretical bounds and heuristic approximations for this optimal policy. Efficiency of these approximations is illustrated via extensive numerical experiments


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