Aaron Levis - Academia.edu (original) (raw)

Papers by Aaron Levis

Research paper thumbnail of A hierarchical solution approach for multi-site capacity planning under uncertainty in the pharmaceutical industry

Computers Chemical Engineering 28 707 725, May 1, 2004

... Pharmaceutical companies are constantly faced with the question of best use of limited resour... more ... Pharmaceutical companies are constantly faced with the question of best use of limited resources available to obtain the highest possible profit and the decisions involved are usually taken in the presence of significant uncertainty. ...

Research paper thumbnail of Customer Demand Forecasting via Support Vector Regression Analysis

Chemical Engineering Research and Design, Aug 1, 2005

T his paper presents a systematic optimization-based approach for customer demand forecasting thr... more T his paper presents a systematic optimization-based approach for customer demand forecasting through support vector regression (SVR) analysis. The proposed methodology is based on the recently developed statistical learning theory (Vapnik, 1998) and its applications on SVR. The proposed three-step algorithm comprises both nonlinear programming (NLP) and linear programming (LP) mathematical model formulations to determine the regression function while the final step employs a recursive methodology to perform customer demand forecasting. Based on historical sales data, the algorithm features an adaptive and flexible regression function able to identify the underlying customer demand patterns from the available training points so as to capture customer behaviour and derive an accurate forecast. The applicability of our proposed methodology is demonstrated by a number of illustrative examples.

Research paper thumbnail of A Mathematical Programming Approach for Multi-site Capacity Planning in the Pharmaceutical Industry

In Proceedings of the 15th International Congress of Chemical and Process Engineering Prague Czech Republic, 2002

Research paper thumbnail of Active demand management for substitute products through price optimisation

OR Spectrum, 2006

This paper presents a systematic mathematical programming approach for active demand management i... more This paper presents a systematic mathematical programming approach for active demand management in process industries. The proposed methodology aims to determine optimal pricing policies as well as output levels for substitute products, while taking into consideration manufacturing costs, resource availability, customer demand elasticity, outsourcing and market competition. First, profit maximisation analytical formulae are derived for determining Nash equilibrium in prices

Research paper thumbnail of Multi-site capacity planning for the pharmaceutical industry using mathematical programming

Computer Aided Chemical Engineering, 2003

This paper presents a systematic mathematical programming approach for long-term, multi-site capa... more This paper presents a systematic mathematical programming approach for long-term, multi-site capacity planning under uncertainty in the pharmaceutical industry. The proposed mathematical model constitutes an extension of the previous work done by Papageorgiou et al. (2001) determining both the product portfolio and the multi-site capacity planning in the face of uncertain clinical trials outcomes. Two distinct decision-making levels are identified,

Research paper thumbnail of Optimisation-based scheduling: A discrete manufacturing case study

Computers & Industrial Engineering, 2005

This work presents the development and implementation of a production scheduling system for an el... more This work presents the development and implementation of a production scheduling system for an electrical appliance manufacturer. Based on recent advances in optimisation-based scheduling approaches, two different software architectures based on two different scheduling formulations, namely the RTN and the STN, are proposed to integrate information available in the different production units and stages with formal algorithmic tools. Optimization results indicate that significant economic benefits can be achieved (e.g. minimization of total operating costs) while ensuring full customer satisfaction as opposed to normal practices followed in the company relying on human expertise. The work indicates that it is possible to solve real-life manufacturing problems using optimization-based approaches but the integration of information in a timely fashion seems to be a major factor in successfully implementing the system and fully realizing its benefits. q (L.G. Papageorgiou).

Research paper thumbnail of A hierarchical solution approach for multi-site capacity planning under uncertainty in the pharmaceutical industry

Computers & Chemical Engineering, 2004

... Pharmaceutical companies are constantly faced with the question of best use of limited resour... more ... Pharmaceutical companies are constantly faced with the question of best use of limited resources available to obtain the highest possible profit and the decisions involved are usually taken in the presence of significant uncertainty. ...

Research paper thumbnail of Virtual plant-wide management and optimisation of responsive manufacturing networks (VIP-NET): An EC collaborative research project

Computer Aided Chemical Engineering, 2004

Abstract This work describes some of the research and technological developments achieved in the ... more Abstract This work describes some of the research and technological developments achieved in the course of VIP-NET, a large EC funded project in the area of manufacturing. A comprehensive strategy and several computer-aided tools have been developed for the ...

Research paper thumbnail of A hierarchical solution approach for multi-site capacity planning under uncertainty in the pharmaceutical industry

Computers Chemical Engineering 28 707 725, May 1, 2004

... Pharmaceutical companies are constantly faced with the question of best use of limited resour... more ... Pharmaceutical companies are constantly faced with the question of best use of limited resources available to obtain the highest possible profit and the decisions involved are usually taken in the presence of significant uncertainty. ...

Research paper thumbnail of Customer Demand Forecasting via Support Vector Regression Analysis

Chemical Engineering Research and Design, Aug 1, 2005

T his paper presents a systematic optimization-based approach for customer demand forecasting thr... more T his paper presents a systematic optimization-based approach for customer demand forecasting through support vector regression (SVR) analysis. The proposed methodology is based on the recently developed statistical learning theory (Vapnik, 1998) and its applications on SVR. The proposed three-step algorithm comprises both nonlinear programming (NLP) and linear programming (LP) mathematical model formulations to determine the regression function while the final step employs a recursive methodology to perform customer demand forecasting. Based on historical sales data, the algorithm features an adaptive and flexible regression function able to identify the underlying customer demand patterns from the available training points so as to capture customer behaviour and derive an accurate forecast. The applicability of our proposed methodology is demonstrated by a number of illustrative examples.

Research paper thumbnail of A Mathematical Programming Approach for Multi-site Capacity Planning in the Pharmaceutical Industry

In Proceedings of the 15th International Congress of Chemical and Process Engineering Prague Czech Republic, 2002

Research paper thumbnail of Active demand management for substitute products through price optimisation

OR Spectrum, 2006

This paper presents a systematic mathematical programming approach for active demand management i... more This paper presents a systematic mathematical programming approach for active demand management in process industries. The proposed methodology aims to determine optimal pricing policies as well as output levels for substitute products, while taking into consideration manufacturing costs, resource availability, customer demand elasticity, outsourcing and market competition. First, profit maximisation analytical formulae are derived for determining Nash equilibrium in prices

Research paper thumbnail of Multi-site capacity planning for the pharmaceutical industry using mathematical programming

Computer Aided Chemical Engineering, 2003

This paper presents a systematic mathematical programming approach for long-term, multi-site capa... more This paper presents a systematic mathematical programming approach for long-term, multi-site capacity planning under uncertainty in the pharmaceutical industry. The proposed mathematical model constitutes an extension of the previous work done by Papageorgiou et al. (2001) determining both the product portfolio and the multi-site capacity planning in the face of uncertain clinical trials outcomes. Two distinct decision-making levels are identified,

Research paper thumbnail of Optimisation-based scheduling: A discrete manufacturing case study

Computers & Industrial Engineering, 2005

This work presents the development and implementation of a production scheduling system for an el... more This work presents the development and implementation of a production scheduling system for an electrical appliance manufacturer. Based on recent advances in optimisation-based scheduling approaches, two different software architectures based on two different scheduling formulations, namely the RTN and the STN, are proposed to integrate information available in the different production units and stages with formal algorithmic tools. Optimization results indicate that significant economic benefits can be achieved (e.g. minimization of total operating costs) while ensuring full customer satisfaction as opposed to normal practices followed in the company relying on human expertise. The work indicates that it is possible to solve real-life manufacturing problems using optimization-based approaches but the integration of information in a timely fashion seems to be a major factor in successfully implementing the system and fully realizing its benefits. q (L.G. Papageorgiou).

Research paper thumbnail of A hierarchical solution approach for multi-site capacity planning under uncertainty in the pharmaceutical industry

Computers & Chemical Engineering, 2004

... Pharmaceutical companies are constantly faced with the question of best use of limited resour... more ... Pharmaceutical companies are constantly faced with the question of best use of limited resources available to obtain the highest possible profit and the decisions involved are usually taken in the presence of significant uncertainty. ...

Research paper thumbnail of Virtual plant-wide management and optimisation of responsive manufacturing networks (VIP-NET): An EC collaborative research project

Computer Aided Chemical Engineering, 2004

Abstract This work describes some of the research and technological developments achieved in the ... more Abstract This work describes some of the research and technological developments achieved in the course of VIP-NET, a large EC funded project in the area of manufacturing. A comprehensive strategy and several computer-aided tools have been developed for the ...