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

Investment decisions in the renewable energy sector: An analysis of nonfinancial drivers

E. Menichetti, A. MASINI

Technological Forecasting and Social Change

mars 2013, vol. 80, n°3, pp.510-524

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

Notwithstanding their many environmental, economic and social advantages, renewable energy technologies (RE) account for a small fraction of the world's primary energy supply. One possible cause for this limited diffusion is that private investments in the RE sector, although potentially appealing, remain insufficient. The lack of adequate financing is also a clear indication that our understanding of the process by which investors fund RE ventures is still incomplete. This paper aims to fill in this gap and to shed new light on RE investment decisions. Building upon behavioral finance and institutional theory, we posit that, in addition to a rational evaluation of the economics of the investment opportunities, various non-financial factors affect the decision to invest in renewables. We analyze the investment decisions of a large sample of investors, with the objective to identify the main determinants of their choices. Our results shed new light on the role of institutional and behavioral factors in determining the share of renewable energy technologies in energy portfolios, and have important implications for both investors and policy makers: they suggest that RE technologies still suffer from a series of biased perceptions and preconceptions that favor status quo energy production models over innovative alternatives

Price Forecasting and Analysis of Exchange Traded Fund


Journal of Mathematical Finance

mars 2013, n°3, pp.181-191

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

Mots clés : Forecasting; Pricing; ETF; Exchange Traded Fund; SPY; Holt¿s Exponential Smoothing; Linear Regression; Multiple Regression; ARIMA Models

ETFs are baskets of securities designed to track the performance of an index. They are designed to provide exposure to broad-based indexes at a lower cost. We first analyzed why ETF should be the choice for an investment. We provide a brief history of this segment, key attributes of ETFs, and investments strategies and implementations with ETFs. The article then presents data analysis and a series of forecasting methods with data analysis techniques to evaluate the per- formance of each method. The data analysis and the forecast evaluation is to determine the best forecasting model for a single ETF; SPY. The different techniques considered include single exponential smoothing, Holt's exponential smoo- thing, simple linear regression, multiple regression and various versions of Box-Jenkins (ARIMA) models. Based on the evaluation of a decade of past historical data, we provide a guidance for the price of our ETF (SPY) using the multiple regression technique (with an R-square of 98.4%), which produced promising results (with low forecast errors of 1% across several forecast metrics), among the different techniques evaluated. Promising results were also obtained using the Multiple regression technique on several other popularly traded ETF's

Specialized capabilities in Integrated Solutions: The Role of Fit

F. Ceci, A. MASINI

International Journal of Business and Systems Research

2013, vol. 7, n°4, pp.395-411

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

Mots clés : Contingency theory, Integrated solutions, IT sector, Information technology, Organisational capabilities, Business models, Degree of fit, Operational environment

Contingency theory suggests that the selection of coherent combinations of organisational capabilities and operational environments has important performance implications. This paper builds upon this perspective to analyse the emergence of a new business model that is modifying the structure of many industries: the provision of integrated solutions. The aim of the paper is to examine the strategic decisions behind the adoption of a business model based on integrated solutions and to understand how internal firm capabilities must be modified to match the external environment. Relying on primary data from 102 European IT firms, we discuss the value of specialised capabilities, and we analyse their degree of fit with the operational environment in which they are applied. Results show that solution providers that possess specialised capabilities obtain greater benefits when they operate in homogeneous environments

The Effect of Environmental Uncertainty on the Tragedy of the Commons


Games and Economic Behavior

novembre 2013, vol. 82, pp.240-253

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

Mots clés : CPR games, Environmental uncertainty, Risk and ambiguity, The tragedy of the commons

We model a common pool resource game under environmental uncertainty, where individuals in a symmetric group face the dilemma of sharing a common resource. Each player chooses a consumption level and obtains a corresponding share of that resource, but if total consumption exceeds a sustainable level then the resource deteriorates and all players are worse-off. We consider the effect of uncertainty about the sustainable resource size on the outcome of this game. Assuming a general dynamic for resource deterioration, we study the effect of increased ambiguity (i.e., uncertain probabilities pertaining to the common resource's sustainable size). We show that whereas increased risk may lead to more selfish behavior (i.e., to more consumption), increased ambiguity may have the opposite effect

The Impact of Cross-Border Patient Movement on the Delivery of Healthcare Services


International Journal of Production Economics

octobre 2013, vol. 145, n°2, pp.702-712

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

Mots clés : Healthcare operations, Cross-border healthcare, Healthcare policy, Game theory

Motivated by a recent legislative discussion in the European Union about providing European patients with the freedom to choose the country they receive treatment, we use a queueing framework to analyze a game-theoretic model that captures the interactions among the patients, the providers, and the healthcare funders. We examine the impact of such “free choice” on the healthcare systems of different countries in equilibrium. Under the assumption that each patient will always prefer to receive care at home when the waiting time is below her individual tolerance level, we show that, in the long run, cross-border patient movement can increase patient welfare due to increased access to care. However, it has a mixed effect on waiting times and reimbursement rates. Moreover, the additional costs of increased access to care are disproportionately shared between the participating countries