Ilias P. Tatsiopoulos

An e-procurement system for governmental purchasing

Abstract During the last few years, a large number of new procurement business models has been developed, mostly concerning companies operating in the private sector. Their main objective is the introduction of new technologies such as e-business for the fulfilment of the procurement process of indirect goods. Lately, such models are also developed for organisations operating in the public sector all over Europe. This paper presents a case study concerning the analysis of the Greek governmental purchasing process carried out from the General Secretariat of Commerce, part of the Ministry of Development and the functions’ definition of the new e-procurement system. The methodological approach as well as the tools used are analysed and the achieved results are presented. The objective of the analysis is the identification of potential problematic areas and the design of new processes in order to maximise the possibilities of a successful implementation of a new e-procurement system. The outcome of the new process design enabled the definition of the analytical functional specifications of the appropriate solution.

Economic aspects of the cotton-stalk biomass logistics and comparison of supply chain methods.

This paper describes a model, which simulates the cotton biomass supply chain. The research has been carried out within the frame of a project that examined the feasibility of producing energy from the chopped cotton-plant stalks after they are cut and after the seed cotton is collected. The heating value of the dry stalks is high and can be used for the production of combined heat and power (CHP co-generation). Thessally is the biggest cotton harvesting area of Greece and Europe. The study focuses on this area where the cotton-stalks are not used for energy production yet. There have not been any studies focusing on the specifications of this renewable source of energy and on the specifications of its harvesting area. This study examines the feasibility and the problems that arise while trying to organize an integrated logistics network and optimize its transportation economy. Also, economic aspects of other logistics procedures like collection and warehousing, are analysed.

Design of an IT-driven decision support system for vehicle routing and scheduling

Abstract This paper presents the development of a decision support system used by an oil downstream company for routing and scheduling purposes. The studied problem refers to a complex delivery process of oil products from a number of distribution centers to all customers. The latest rapid advance of operations research (OR) applications, in the form of advanced planning and scheduling (APS) systems, has shown that OR algorithms can be applied in practice if (a) they are embodied in packaged information technology (IT) solutions, (b) the interface problems to mainstream ERP software applications are solved. In this study the utilisation of advanced IT systems supports effectively the planning and management of distribution operations. The combination of a supply chain management (SCM) application with a geographical information system (GIS) integrated with an enterprise resource planning (ERP) software resulted to this innovative decision support tool. The objectives of this new tool are: optimum use of the distribution network resources, transportation cost reduction and customer service improvement. The paper concludes with the benefits of the new system, emphasising at how new technologies can support transportation processes with the help of operations research algorithms embedded in software applications.

Decision support models for solid waste management: Review and game-theoretic approaches

This paper surveys decision support models that are commonly used in the solid waste management area. Most models are mainly developed within three decision support frameworks, which are the life-cycle assessment, the cost-benefit analysis and the multi-criteria decision-making. These frameworks are reviewed and their strengths and weaknesses as well as their critical issues are analyzed, while their possible combinations and extensions are also discussed. Furthermore, the paper presents how cooperative and non-cooperative game-theoretic approaches can be used for the purpose of modeling and analyzing decision-making in situations with multiple stakeholders. Specifically, since a waste management model is sustainable when considering not only environmental and economic but also social aspects, the waste management bargaining game is introduced as a specific decision support framework in which future models can be developed.

The integration of activity based costing and enterprise modeling for reengineering purposes

Abstract This paper describes an approach to integrate the Activity Based Costing (ABC) technique within the framework of GRAI Integrated Methodology (GIM) in order to assist business process reengineering justification and evaluation. The first step of integration is to have ABC adopt cost pools and lists of activities derived from GIM process modeling. Further on ABC is involved in two stages of the methodology: (a) ABC adds to the ECOGRAI method of performance modeling by supporting the determination of the right performance indicators that are responsible for business process costs. (b) ABC is a sound approach to translate operational performance indicators not found in accounting ledgers into financial terms and the companys profit bottom line. The approach has been developed during the Esprit research project REALMS and implementation results from two industrial partners are presented.

On the unification of bills of materials and routings

Abstract This paper examines first the far-reaching consequences of unifying bills of material and routings on the basic functions of production planning and control, i.e.: (a) On the structure of the production database and the opportunity for significant simplification; (b) On the mid-term planning of materials and capacities (traditional MRP and CRP software modules) and the chances for simultaneous planning of materials and capacities; (c) On the opportunity to support the extended enterprise and lean production concepts through better planning of the supply chain; (d) On shop floor control and the chances for reducing the volume of transactions and apply more effective scheduling strategies. In parallel, the paper proposes a new production planning and control (PPC) concept which capitalizes on the above consequences. This concept has led to the development of a PPC software system that uses the traditional and widely accepted MRP processing logic, thus avoiding the intricacies of the OPT system and being much more readily accepted by manufacturing personnel.

Combined municipal solid waste and biomass system optimization for district energy applications

Municipal Solid Waste (MSW) disposal has been a controversial issue in many countries over the past years, due to disagreement among the various stakeholders on the waste management policies and technologies to be adopted. One of the ways of treating/disposing MSW is energy recovery, as waste is considered to contain a considerable amount of bio-waste and therefore can lead to renewable energy production. The overall efficiency can be very high in the cases of co-generation or tri-generation. In this paper a model is presented, aiming to support decision makers in issues relating to Municipal Solid Waste energy recovery. The idea of using more fuel sources, including MSW and agricultural residue biomass that may exist in a rural area, is explored. The model aims at optimizing the system specifications, such as the capacity of the base-load Waste-to-Energy facility, the capacity of the peak-load biomass boiler and the location of the facility. Furthermore, it defines the quantity of each potential fuel source that should be used annually, in order to maximize the financial yield of the investment. The results of an energy tri-generation case study application at a rural area of Greece, using mixed MSW and biomass, indicate positive financial yield of investment. In addition, a sensitivity analysis is performed on the effect of the most important parameters of the model on the optimum solution, pinpointing the parameters of interest rate, investment cost and heating oil price, as those requiring the attention of the decision makers. Finally, the sensitivity analysis is enhanced by a stochastic analysis to determine the effect of the volatility of parameters on the robustness of the model and the solution obtained.

Risk management as a strategic issue for the implementation of ERP systems: a case study from the oil industry

The introduction of complicated and expensive Enterprise Resource Planning Systems (ERP) in companies operating in the process industry has become a strategic issue. The success of Information Technology (IT) implementation projects is dependent upon technological issues (software and hardware), the design of new efficient processes and the utilisation of human resources that will participate in new processes using the new IT solution. Risk management can be an important component of strategy helping in the identification and control of project-related risks. The methodology presented in this paper proposes a structured risk management approach for the successful implementation of ERP systems. The application of the proposed methodology is demonstrated within a case study concerning a European company operating in the petroleum sector. The conclusion drawn by the study is that the risk management strategic approach is of significant importance when the best outcome from the implementation of an ERP project in industry needs to be obtained.

Electricity and combined heat and power from municipal solid waste; theoretically optimal investment decision time and emissions trading implications

Waste management has become a great social concern for modern societies. Landfill emissions have been identified among the major contributors of global warming and climate changes with significant impact in national economies. The energy industry constitutes an additional greenhouse gas emitter, while at the same time it is characterized by significant costs and uncertain fuel prices. The above implications have triggered different policies and measures worldwide to address the management of municipal solid wastes on the one hand and the impacts from energy production on the other. Emerging methods of energy recovery from waste may address both concerns simultaneously. In this work a comparative study of co-generation investments based on municipal solid waste is presented, focusing on the evolution of their economical performance over time. A real-options algorithm has been adopted investigating different options of energy recovery from waste: incineration, gasification and landfill biogas exploitation. The financial contributors are identified and the impact of greenhouse gas trading is analysed in terms of financial yields, considering landfilling as the baseline scenario. The results indicate an advantage of combined heat and power over solely electricity production. Gasification, has failed in some European installations. Incineration on the other hand, proves to be more attractive than the competing alternatives, mainly due to its higher power production efficiency, lower investment costs and lower emission rates. Although these characteristics may not drastically change over time, either immediate or irreversible investment decisions might be reconsidered under the current selling prices of heat, power and CO 2 allowances.

An Orders Release reference model as a link between production management and shop floor control software

Abstract This paper presents a data-oriented reference model for the Orders Release process that forms the link between the production planning system and the production execution system. The terms planning system and execution system are recursively meant at all levels of the ISO manufacturing model (enterprise-factory-cell-work centre). A Releaser generic architecture is described in the form of a module structure that includes an Order Manager, a Material Manager and a Capacity Manager. The architecture is further decomposed into a data model layer and a function layer building a reference model with generic, partial and particular views. Those views are based on a production systems typology and the analysis of the influence of the typological characteristics on the Orders Release process.