Irene Pluchinotta
email: irene.pluchinotta@gmail.com

Multi-Agent Modelling to support Decision in Water Management: A Case-Based Approach

Keywords: Water management, Aiding decision-making, Multiple agents, System Dynamics, Cooperative models, Interactions, Participatory modelling

Due to the disparity of interests associated with a shared resource, the political dimension of contemporary water management is an important factor in conflicts among stakeholders. In this sense, environmental decision-making takes place in a highly interconnected system, in which neither the decisional ramifications nor the complexity of its impacts, can be neglected. The Mediterranean Region is characterized by water scarcity. This problem is increasingly challenging human and more-than-human communities, developing the need of a dynamic support in complex decision-making processes. A Multi-Agent System approach and System Dynamics modelling can introduce unconventional alternatives that can combine physical and economical components, with the consequences of individual behaviors in the management of a common resource, namely water. The paper works on analysis carried out in the irrigation water management in the Apulia region and a case-based modelling approach is suggested.

Introduction

The management of natural and renewable resources must take account of both resource and social dynamics, such as the existence of belief system and cultural norms [START_REF] Bousquet | MAS and ecosystem management: a review[END_REF]. Complex human behaviors and natural-artificial systems produce remarkable impacts on global environments [START_REF] Borri | Planning urban microclimate through multiagent modelling: A cognitive mapping approach[END_REF]. Water supply systems often engage multiple stakeholders with conflicting interests [START_REF] Fang | Interactive decision making: the graph model for conflict resolution[END_REF]. In this sense, water management is a "messy" problem, as a result of various interests associated with a shared resource, originated from the failure to meet basic human needs, inappropriate or ineffective institutions and the inability to balance human needs with the needs of the natural world. Furthermore according to Ostrom [START_REF] Ostrom | Governing the Commons: The Evolution of Institutions for Collective Action[END_REF], the tragedy of what economists call common-pool resources, could be avoided under the right conditions: local communities can manage shared resources sustainably and successfully. The importance of shared decision processes in water management derives from the awareness of the inadequacy of traditional engineering approaches in dealing with complex and ill-structured problems. It is becoming increasingly obvious that traditional problem solving and decision support techniques, based on optimization and factual knowledge, have to be combined with stakeholder based policy design and implementation [START_REF] Giordano | Bayesian Belief Network to support conflict analysis for groundwater protection: The case of the Apulia region[END_REF]. New approaches to water planning and management that incorporate principles of sustainability and equity are required [START_REF] Gleick | A Human Right to Water[END_REF] and consequently, the environmental decision-making takes place in a highly interconnected system, in which it is not possible to ignore the decisional network or the complexity of its impacts. However, the participative decision process with public actors and public objects is an unpredictable scenario for the great variety of objects and for the competition between intervening actors. For this reason, in order to ensure the sustainable development of water resources and their dependent societies and environments, there is an increasingly recognized need for the development of improved approaches to aid multi-stakeholder decision-making in the water sector [START_REF] Daniell | Real world decision-aiding: a case of participatory water management[END_REF]. After this introduction, the next chapters explain briefly the modelling theories and the agent based framework carried out from the case study. The paper ends up with follow-ups.

2

Multi-paradigm modelling approach

The need for the involvement of a number of different agents during planning processes induced issues of: gathering and exchanging complex knowledge, representing structured concepts, supporting different formal/informal languages [START_REF] Borri | Distributed knowledge in environmental planning: Hybrid IT-based approaches in scenario-building contexts[END_REF] and structuring architecture interactions. Environmental systems are being viewed in terms of a set of autonomous agent due to several factors: multiple decision-makers, competing interest, complex and highly distributed network, inoperative distribution of resources, environmental and social impacts and difficulties of building scenario in a dynamic system. Different approaches for agent-based simulation have already been discussed in the literature (e.g. [START_REF] Bousquet | MAS and ecosystem management: a review[END_REF][START_REF] Camarda | Cooperative scenario building in environmental planning: Agents, roles, architectures[END_REF][START_REF] Bousquet | An environmental modelling approach: the use of multi-agent simulation[END_REF][START_REF] Ferber | MAS: An Introduction to Distributed Artificial Intelligence[END_REF][START_REF] Doran | Intervening to Achieve Co-operative Ecosystem Management: Towards an Agent Based Model[END_REF]). These approaches seem interesting since they permit the coupling of environmental and social systems, thus allowing to model both disaggregated human decision making [START_REF] Hare | Further towards a taxonomy of agent-based simulation models in environmental management[END_REF] and social structures of interaction in environmental management.

In this framework, a Multi-Agent System (MAS) approach and System Dynamics (SD) modelling can introduce unconventional alternatives that can combine physical and economical components, with the consequences of individual behaviors in the management of a common resource, namely water. The use of a multiple-agent approach shows new potentials to support the complex scenarios embedded with the multifaceted problem of managing water and it is useful to formalize the behaviors of water users in the knowledge management structure [START_REF] Ferber | MAS: An Introduction to Distributed Artificial Intelligence[END_REF][START_REF] Camarda | Cooperative scenario building in environmental planning: Agents, roles, architectures[END_REF]. Combining MAS modeling and SD simulation allows to deal equally with structural and behavioral models [START_REF] Scholl | Agent-based and system dynamics modelling: a call for cross study and joint research[END_REF]. Originated from the field of Distributed Artificial Intelligence, MAS are based on the principles of distribution and interaction [START_REF] Weiss | MAS: a modern approach to distributed artificial intelligence[END_REF][START_REF] Wooldridge | Intelligent agents[END_REF]. MAS is a set of agents in a certain environment that interact with an appropriate organization to coordinate their behavior [START_REF] Ferber | MAS: An Introduction to Distributed Artificial Intelligence[END_REF]. In such systems, not all agents are equal: each agent can have unique capabilities and objectives, representing its real-world counterpart. An Agent can be defined as an autonomous entity and it has the capacity to adapt itself when its environment changes [START_REF] Wooldridge | Intelligent agents[END_REF]. Furthermore, System Dynamics is a powerful and versatile simulating tool for studying easily dynamic characteristics of large complex systems. SD was defined by J.W. Forrester [START_REF] Forrester | Industrial dynamics[END_REF] as a way of studying the behavior of systems to show how policies, decisions, structure, and delays are interrelated to influence growth and stability. SD can be helpful to elicit and integrate conceptual models and the core of this structure is composed of feedback loops (positive and negative) that integrate the three fundamental constituents: state, rate, and information [START_REF] Vennix | Group Model Building: Facilitating Team Learning Using System Dynamics[END_REF]. The final aim of the current research activity is to support knowledge elicitation from different decision makers and to simulate future scenarios, both desirable or not, in a distributed and highly interconnected water management network. From the prescriptive point of view, the research activity has the objective of modelling and interpreting the architecture of interactions between involved agents, to formalize the behaviors of water users and the consequences of their actions on the system.

A Case-Based Modelling

The complexity of a water management situation is largely driven by: the number of uncertainties, the number of interrelations between agents and the number and level of conflicts present [START_REF] Daniell | Real world decision-aiding: a case of participatory water management[END_REF]. The paper works on analysis carried out in the irrigation water management in agricultural systems in the Apulia region (south Italy). The simulations of scenarios on this case-based approach are used to analyze the consequences of sets of actions made by agents as an issue of coherence among sets of rules in a given environment. Different agents with different roles and behaviors can affect the environment, while performing their single and/or collective activities. Simulation lead to describe the overall behavioral patterns of the virtual system, interpreted as theories for real irrigated systems and proposing new insights on irrigated systems. Let us define the system as 5-plets {E, O, A, R, S} made of: an environment E, a set of objects O, an assembly of agents A which represent the active entities in the system, an assembly of relations R that link objects (and therefore agents) to one another and S a set of rules and strategies, making it possible for the agents to perceive, produce, transform and manipulate objects in O. The taxonomy of agents, objects and the formal and informal interaction have been created through two steps of semi-structured interviews with the stakeholders, dealing with conflict identification and resolution in natural resource management to achieve the "shared vision of the problem" [START_REF] Tsoukiàs | An explicative model of 'public' interorganizational actions[END_REF]. The validation of the model has been done with a focus group and single interviews. In this sense, defining the set of elements, the relations between the sets and the behavioural rules allow to build the final model. Within the case-study analysed, the stakeholders are: Farmers, Water managers (political and technical side), the Regional Authority and Analysts. The Water Manager Consortium of Capitanata has to deal with the scarcity of water of the region and with the request of water from each farmer. Farmers have to share the same resource. Each Farmer in order to maximize his profits chooses the right mix crops with regard to the quantity of available water and the hectares of arable land.

In dry season, farmers receive the information of the water lack with delay and they can choose different alternatives like paying for a water surplus or using the groundwater. The groundwater (GW) overexploitation brings about social and environmental problems and the regional Authority, the Apulia Region, needs to protect groundwater quality and to keep a high level of productivity of the agricultural sector. It is possible to identify two different level of decision: one problem is embedded within another. The first level concerns the decision of the Water Manager of available water for each farmer.

The second level affects the farmers, their crop planning and management of available water and its price. The boundaries of this system are given by the assumption of the irrigated system is a place for acquisition and allocation of water and credit; the water allocation is the combination of actions which enable users to receive water according to a recognized system of rights and priorities. The characteristics of the system constraints are economical (i.e. water price, market rules) and associated to the volume of available water. For each farmer sets of attributes, strategies and relations have been defined through the identification of a large numbers of parameters (such as level of autonomy, social aptitudes, communication rules, distributed decision-making, ability to influence environment, coherence in sensing environment). In addition, the identification of the object hierarchy allow to understand how concrete or abstract objects are related to each other's. For example some objects are: expected water demand, farmers' perception of water availability, irrigation budget, irrigated area, GW availability, acceptability.

A general overview of the model is in the figure below. The final model shows that the macro behavior of a system is primarily determined by its internal microstructure. In detail, the constructive process pays particular attention to structuring a shared vision of the problems and the model-building process is aimed at directly allowing the stakeholder to make decisions for themselves, understanding the consequences on the system of their possible actions. With this aim, the case-based model develops an integrated methodology able to combine hydrological, socioeconomic and behavioral determinants of water use to support resource protection.

Conclusions and final discussion

In complex and strongly interconnected systems as the water management system, it is important to analyze the ramifications of the decision-making processes and the interaction between involved agents. To this aim, methods and tools to elicit and structure the actors of the water management problem are particularly interesting. This paper shows the potentials of using an agent based framework to simulate environmental resource management and to manage complex knowledge involved in a multi-stakeholder behaviors system. A Multi Agent system architecture and System Dynamics simulation allow the enhancement of the interaction and the participation of water users in the governance process. This is due to their ability to explain the dynamism of a system by modelling the roles of social interaction and adaptive, disaggregated (micro-level) human decision-making in environmental management.

Fig. 1 .

 1 Fig. 1. General overview of the final model

Supervisors: Prof. D. Borri (DICATECh, Technical University of Bari) and Prof. A. Tsoukiàs (LAMSADE, University Paris Dauphine) Co-supervisors: Prof. Domenico Camarda (DICATECh, Technical University of Bari)


Daniel Ritter
email: daniel.ritter@sap.com

Towards a Business Network Management

Keywords: Business Networks, Business Network Management, Business Network Virtualization, Business Processes, Integration Middleware, Linked (Business) Data, Network Mining

des établissements d'enseignement et de recherche français ou étrangers, des laboratoires publics ou privés.

Introduction

Enterprises are part of value chains consisting of business processes with intra and inter enterprise stakeholders. To remain competitive, enterprises need visibility into their business networks and ideally into relevant parts of partner and customer networks and processes. However, currently the visibility often ends at the borders of systems or enterprises. Business Network Management (BNM) helps to overcome this situation and allows companies to get insight into their technical, social and business relations. However, the relevant information is hidden in complex, dynamic and heterogeneous enterprise domains.

In previous work, we introduced the domain of Network Mining (NM) [START_REF] Ritter | From Network Mining to Large Scale Business Networks[END_REF], which allows to discover this information from the different business process and integration domains. The extracted raw data contains the information necessary to reconstruct the different network perspectives as well as to semantically link them into one business network [START_REF] Ritter | Business Network Reconstruction using Datalog[END_REF]. An example for a business network is given in Fig. 1, which shows participants in a business process network of a (cross-) enterprise partner network (front) and the corresponding technical network on which these processes are implemented (back). The participants of the business process network represent business artifacts within an enterprise, that are related to participants within a partner network. The participants and relationships are considered complex and contain the underlying business processes, which specify e.g. a business document or goods exchange between related participants. These business processes are actually implemented within the applications and integration capabilities of the enterprises denoting a more technical network, called integration network. This network consists of applications and integration middleware for internal business processes related to processes interacting with business partners like suppliers, transport carriers, dealers. In this position paper, we introduce a new enterprise and linked data domain, the Business Network Management, which helps enterprises to get insight into their business networks. Based on previous work in the area of Network Mining [START_REF] Ritter | From Network Mining to Large Scale Business Networks[END_REF], we show how to bridge the gap from the NM raw data towards reconstructed business networks. For that, we use the concept of a virtualized business network, which extends the capabilities of NM from discovery to enrichment and re-deployment of information as required for the management of business networks. While developing the domain towards BNM, we discuss relevant areas for research and set them into context with the state-of-the art up to our knowledge. We conclude with a description of customer cases, which state the current progress of our BNM system.

In section 2 we introduce network virtualization to extend the Network Mining approach. On this foundation we define BNM in section 3 and discuss our prototypical application to real-world enterprise landscapes. We conclude with related work and draw conclusions.

The Virtualized Business Network

Business Network Virtualization (BNV) is the process of combining network resources and network functionality into a single, software-based administrative entity called (virtual) business network. Within business networks, this allows for efficient utilization, manageability and regulatory compliance. For business networks, we distinguish several levels of virtualization and their options shown in Fig. 2. The first level (L1) specifies the retrieval and interpretation of business process and integration content as well as operation information, which can be extended as second option by runtime artifacts. Therefore, e.g. integration artifacts are implemented in domain or vendor specific tools, but displayed within the business network. The integration or business errors are fixed within the domain-specific tools. To bring this to the second level (L2), application, design time and operation integration content is encapsulated and generated from the business network. For instance, when the business network is visualized, business process and integration artifacts can be defined on the network as expert knowledge and deployed back to the specific integration technology. Based on level 2, the integration content are enriched by process and information flow models (L3). These models allow a drill-down e.g. to the channel, interface, binding or processing level of the integration technology. As second option to L3, the process and integration flow models are interpreted and executed in one system integrated in the heterogeneous applications and integration technology runtimes.

The levels of virtualization conceptually ground an extended definition of mining Business Networks. The virtualization level L1 corresponds to the first two types of Network Mining (NM), i.e. discovery and conformance, in [START_REF] Ritter | From Network Mining to Large Scale Business Networks[END_REF] and covers the discovery, extraction and domain specific analysis of relevant data from dynamic, distributed and heterogeneous enterprise landscapes. Fig. 3(a). shows all three types including network enhancement. The third type of network mining is enhancement, which covers re-deployment. Here, the idea is to extend or improve an existing network model using domain expert knowledge about the actual business network. Whereas conformance measures the alignment between model and reality, this type aims at changing or extending the "as-is" model. For instance, the "as-is" model of the network can be refined and extended by introducing new relationships on the network, which results in an integration channel re-deployment within the specific middleware. This corresponds to levels L2 and L3 of BNV, which is the most difficult part of NM and requires a bijective mapping between domain-specific and the (virtual) business network model. In case of external linked data, re-deployment would mean to e.g. post messages into dedicated social media or add new connections to a special profile from an abstract social network view.

Fig. 3(b) summarizes the three NM types in terms of input and output. Techniques for discovery take domain-specific raw data and produce a network model. The discovered models are typically completely diverse like configuration, system landscape, business process models. Conformance checking techniques need that raw data and the network model as input. The output consists of verification information showing differences and commonalities between model and data. Techniques for model enhancement and re-deployment, e.g. repair, extension, need the raw data, the model and optionally expert knowledge as input. The output is an improved or extended model. The custom information can come from various personas which are experts in one of the many domains the raw data comes from. Their knowledge and experience is important and is brought into NM through the custom extensions.

Business Network Management

The idea of Business Network Management (BNM) is to discover, make visible, monitor (operations) and improve real-world business networks and underlying processes by extracting information from various sources readily available in today's (information) systems. The automated data discovery, conformance checking and enhancement is done by NM resulting in a (virtual) network model. This data is input to inference mechanisms which derive the real "as-is" business network and later a business network spanning across enterprises. With that, BNM aims to ease the end-to-end lifecycle behind integration developments and allows collaboration on different information for faster execution. The network gives a generalized view of an enterprise integration and business landscape.

Today this challenge is addressed with documentation and systems management, but leaves manual work for IT administrators and integration experts to gather a consistent view of the network. The basic steps within BNM are depicted in Fig. 4. The real "as-is" network is computed based on the data from NM and visualized showing views on business and integration networks as well as their semantic relationships, e.g. processes implemented by middleware systems or applications. Domain experts work on these views by contextualizing, enriching and adapting the network to their needs, e.g. label or group entities. Thereby the experts analyze the "as-is" network and enhance it by e.g. adding new entities. The enhanced network is closer to the "to-be" network, which influences the general "to-be" business process picture derived from BPM or Process Mining (PM) [START_REF] Van Der Aalst | Process Mining: Discovery, Conformance and Enhancement of Business Processes[END_REF][START_REF] Van Der Aalst | Process Mining Manifesto[END_REF]. For that, feedback from the operation on the network is taken into account, e.g. monitoring.

Fig. 4. Business Network Management cycle showing influencing and contributing domains to the "as-is" network computation towards a "to-be" network enhancement

The Business Network Management Prototype

To demonstrate the "as-is" network computation and assess the approach with customers, we developed a virtualization level L1 prototype, that auto-discovers and graphically represents integration networks. We applied the system to realworld customer landscapes containing mediated communication through middleware systems, e.g. SAP Process Integration (SAP PI) [START_REF]SAP Process Integration[END_REF], direct connectivity, e.g. web services, and system landscape information, e.g. [START_REF] Hengevoss | SAP NetWeaver System Landscape Directory -Grundlagen und Praxis[END_REF]. An excerpt of the computed integration network from a big manufacturing company is shown in Fig. 5(a). The network consists of participants representing the logical senders and receivers of messages, e.g. application systems and technical endpoints representing a business partner application/server. On a separate screen detail information is shown, e.g. system descriptions or installed products for an application system (not shown). Moreover, the network shows all message exchanges between the selected participants as drill-in on top-level connections, see Fig. 5(b). For each message exchange additional attributes that constitute and describe the message exchange is shown, e.g. technical information like interfaces and transport protocol used or runtime information like last used time.

This application to real-world enterprise landscapes allowed the evaluation of cross-middleware inference, combination of embedded and mediated communication and fragmented information registered in different domains. With that we showed that the BNM approach is valid and resulted in highly reliable and usable results. Moreover, our system is helpful in the everyday work of integration experts, since it gives an overview of the complete "as-is" network, which is very difficult to identify using existing middleware tools. The system reduces the effort to document integration scenarios and helps to answer questions that are difficult to find today. For instance, when combing configuration and runtime data, it is possible to find unused and possibly obsolete interfaces and flows. Hence, with this system, several customers plan upgrade projects of their middleware content, which will substantially save migration time and effort.

Related Work

This work builds on previous work conducted in [START_REF] Ritter | From Network Mining to Large Scale Business Networks[END_REF], which discusses how to come from Network Mining to large scale business networks. The contribution of this paper starts with the definition of Business Network Virtualization, which is used to extend the definition of Business Network towards the Business Network Management.

The most influencing related work is conducted in the area of Process Mining (PM) initiated by [START_REF] Van Der Aalst | Process Mining Manifesto[END_REF][START_REF] Van Der Aalst | Process Mining: Discovery, Conformance and Enhancement of Business Processes[END_REF], which is a relatively young research discipline that sits between computational intelligence and data mining. It has similar requirements for data discovery, conformance and enhancement. However, its approach and goals are different. PM strives to derive Business Process Management (BPM) models from process logs. From that, models are automatically generated and checked. PM as well as BNM complement BPM by making it visible through automated discovery and in case of BNM to set the business processes in a broader context to each other.

Similar to Process Mining, Semantic Business Process Management (SBPM) [START_REF] Hepp | Semantic Business Process Management -A Vision Towards Using Semantic Web Services for Business Process Management[END_REF] strives to mine business processes semantics mechanically. For that, an ontological approach [START_REF] Hepp | An Ontology Framework for Semantic Business Process Management[END_REF][START_REF] Filipowska | Organisational Ontology Framework for Semantic Business Process Management[END_REF] is combined with Semantic Web Services (SWS) and BPM. As in the Process Mining case, SBPM and Business Network Management are complementing approaches with combinable technology stacks.

Gaining insight into the network of physical and logical nodes within companies could be a future extension of BNM, but is not primarily relevant for visualizing and operating business networks. This domain is mainly addressed by the IT service management [START_REF] O'neill | Topic Overview -IT Service Management[END_REF] and virtualization community [START_REF] Chowdhury | Network virtualization: state of the art and research challenges[END_REF].

The linked (web) data research, conducted by Bizer, and Berners-Lee et al. [START_REF] Bizer | Linked Data -The Story so Far[END_REF][START_REF] Bizer | The Emerging Web of Linked Data[END_REF], shares similar approaches and methodologies, which have so far neglected linked data within enterprises.

Discussion and Future Work

In this position paper, we introduce a new enterprise and linked (business) data domain. We showed how the concept of Business Network Virtualization is used to extend Network Mining towards the Business Network Management. We showed excerpts of a real-world integration enterprise network in our Business Network Center to illustrate how BNM systems could look like. Future work will be conducted especially for the virtualization levels L2 and L3, i.e. re-deployment and operations on the network, as well as discovering, inferring and making visible further aspects of business networks (for L1). Thus letting them grow to cross-enterprise partner networks in one dimension and towards BPM and network virtualization in the other dimension.

Fig. 1 .

 1 Fig.1. Sample (cross-) enterprise Business Network showing business participants, denoted as nodes, and business document exchange as edges (front) as well as an integration network perspective (back). Enterprises are characterized by their roles they play within a process.

Fig. 2 .

 2 Fig. 2. Sample (cross-) enterprise Business Network showing business participants, denoted as nodes, and business document exchange as edges. Enterprises are characterized by their roles they play within a process

Fig. 3 .

 3 Fig. 3. Business Network Mining extended

Fig. 5 .

 5 Fig. 5. Integration network visualization showing a view on the network (left) and details of the conversations (right)


Peggy E Chaudhry
email: peggy.chaudhry@villanova.edu

Sohail S Chaudhry
email: sohail.chaudhry@villanova.edu

Kevin D Clark
email: kevin.d.clark@villanova.edu

Darryl S Jones
email: djones21@villanova.edu

Enterprise Information Systems Security: A Case Study in the Banking Sector

Keywords: Enterprise information systems, security, conceptual model, banking sector, case study

One important module of Enterprise Information System (EIS) is the development and implementation of the security component of EIS. Furthermore, this EIS Security structure needs to be monitored through the corporate governance of the firm. Based on a literature review and our previous work, we identified four key pillars of a model for EIS Security. These pillars are Security Policy (e.g., set rules for employee behavior), Security Awareness (e.g., continued education of employees), Access Control (e.g., access linked to employee job function), and Top Level Management Support (e.g., engrain information security into the company's culture). We explore the relevance of this model using a case study approach by way of interviewing top-level information systems mangers in the banking sector. We validate the model through using key informant in-depth interviews and qualitative research methods.

Introduction

Enterprise Information Systems (EIS) are companywide Information Technology (IT) systems that companies use to combine multiple business functions information into one data warehouse. They "enable a company to integrate the data used throughout its entire organization [START_REF] Davenport | Putting the Enterprise into the Enterprise System[END_REF]." The plethora of information technologies developed and improved over the last few decades has made business decisions easier for managers who now have all of the relevant information available from one access point without the fear of missing or overlapping information. A problem that results from this convenience is that all company information is now available in one location. This centrality makes a company's intellectual property, one of its core competitive advantages, more vulnerable. Security breaches (malicious or unintentional) can result in continuity disruption, poor reliability of information, lowered effectiveness and efficiency of processes, and can even have legal implications. The current events of external information security problems related to information access, such as the hacker who obtained the personal information of 77 million consumers at Sony's PlayStation Network is testimony to the problems that companies will continue to face with security breaches [START_REF] Sherr | Sony Faces Lawsuit Over PlayStation Network Breach[END_REF]. However, in this paper, we are not addressing so-called "Hack attacks" but will be evaluating the risk of internal information security dilemmas, such as employees of the firm either intentionally or unintentionally compromising the data stored. Overall, firms must safeguard their employee access to the "keys to the kingdom" (e.g., accounts and passwords) [3]. Until recently, most of the concern regarding security in enterprise information systems was more of a technical nature (e.g., viruses, worms, Trojans, etc.), however, more research is finding that human interaction with the systems is the real cause of most breaches [START_REF] Boss | If Someone is Watching, I'll Do What I'm Asked: Mandatoriness, Control, and Information Security[END_REF], [START_REF] Keller | Information Security Threats and Practices in Small Businesses[END_REF], and [START_REF] Sumner | Information Security Threats: A Comparative Analysis of Impact, Probability, and Preparedness[END_REF]. In fact, Sachlar Paulus, Senior Vice-President of Product and Security Governance of SAP (a global EIS provider) has stated that "The weakest link is still people … the biggest problems occur wherever technology comes into contact with people who need to administer, manage, or even use IT security functionality [START_REF] Walsh | The ERP Security Challenge[END_REF]."

2 Liter atur e Review Up until the last few years, most of the research done on corporate dealings with security in EIS focused mainly on the technical aspect of IT such as firewalls and anti-virus software which rely more on technology than the employees using the systems. In fact, as recent as 2005, Siponen believed "the importance of the socioorganizational nature of (E)IS is not recognized seriously enough by traditional Information Systems Security methods" [START_REF] Siponen | An Analysis of the Traditional IS Security Approaches: Implications for Research and Practice[END_REF]. Researchers are now starting to realize that the human interaction with the EIS of the firm is just as important, if not more, than the technical -and that information security cannot be achieved solely through these technological tools [START_REF] Herath | Protection Motivation and Deterrence: A Framework for Security Policy Compliance in Organisations[END_REF]. Many researchers now believe the biggest threat to information security remains internal [START_REF] Boss | If Someone is Watching, I'll Do What I'm Asked: Mandatoriness, Control, and Information Security[END_REF], [START_REF] Vroom | Towards Information Security Behavioural Compliance[END_REF], and [START_REF] Kankanhalli | An Integrative Study of Information Systems Security Effectiveness[END_REF]. Swartz [START_REF] Swartz | Protecting Information from Insiders[END_REF] outlined several cases in which employees stole data while still working for their company, yet the majority of employee security breaches occur accidently or unintentionally [START_REF] Keller | Information Security Threats and Practices in Small Businesses[END_REF] and [START_REF] Sumner | Information Security Threats: A Comparative Analysis of Impact, Probability, and Preparedness[END_REF]. There are currently many theories on the best way to combat these issues. These range from the importance of cultivating an information security policy to significance of employee training and awareness. Overall, just a few researchers have developed frameworks to help companies secure their systems [START_REF] Kankanhalli | An Integrative Study of Information Systems Security Effectiveness[END_REF], [START_REF] Singh | Secure Activity Resource Coordination: Empirical Evidence of Enhanced Security Awareness in Designing Secure Business Processes[END_REF], and [START_REF] Knapp | Information Security Policy: An Organizational-Level Process Model[END_REF].

Infor mation Secur ity Policy

An information security policy is the set of rules, standards, practices, and procedures that the company employs to maintain a secure IT system. It has been said that the "credibility of the entire information security program of an organization depends upon a well-drafted information security policy [START_REF] Kadam | Information Security Policy Development and Implementation[END_REF]." Many experts now think that the development of an information security policy is one of the most practical ways to preserve protected systems [START_REF] Knapp | Information Security Policy: An Organizational-Level Process Model[END_REF] and [START_REF] Myyry | What Levels of Moral Reasoning and Values Explain Adherence to Information Security Rules? An Empirical Study[END_REF]. Knapp et al. [START_REF] Knapp | Information Security Policy: An Organizational-Level Process Model[END_REF] believe that "the development of an information security policy is the first step toward preparing an organization against attacks from internal and external sources." They actually developed an information security policy process that companies can use to develop and analyze their current programs.

Employee Awareness

"Creation and maintenance of security awareness include both individual and collective activities, i.e. education and awareness-raising initiatives, e.g. emails, pamphlets, mouse pads, formal presentations, and discussion groups" [START_REF] Hagen | Implementation and Effectiveness of Organizational Information Security Measures[END_REF]. Many researchers now believe that employee awareness is one of the best ways to protect a company's data [START_REF] Singh | Secure Activity Resource Coordination: Empirical Evidence of Enhanced Security Awareness in Designing Secure Business Processes[END_REF] and [START_REF] Chang | On Security Preparations against Possible IS Threats across Industries[END_REF]. In fact, empirical research found that awareness creation is the most effective information security measure [START_REF] Hagen | Implementation and Effectiveness of Organizational Information Security Measures[END_REF]. Security training and education programs should aim to make employees recognize the legitimacy of information security policy to safeguard the firm [START_REF] Son | Out of Fear or Desire? Toward a Better Understanding of Employees' Motivation to follow IS Security Policies[END_REF].

Access Control

Access control is defined as the process a company takes to limit the access an employee has to various functions of the business; particularly functions not relevant to their position or containing more information than they should have access to [START_REF] She | Security for Enterprise Resource Planning Systems[END_REF]. She and Thuraisingham [START_REF] She | Security for Enterprise Resource Planning Systems[END_REF] stated that many companies now use Role Based Access Control (RBAC), which is a way to limit employee access by permissions, roles, users, and constraints. Access control requirements can be driven by a need for customer, stockholder, and insurer confidence; privacy of personal information; prevention of unauthorized financial asset distribution and adherence to professional standards, among others [START_REF] Sandhu | Role Based Access Control Models[END_REF]. In addition, so long as information is stored and consumed within one organization, security policy and access controls can be optimized for internal use, and access by people from outside of the company can be prevented [START_REF] Sinderen | Challenges and Solutions in Enterprise Computing[END_REF]. However most enterprise information systems are connected to the internet, which can blur the boundaries of enterprise information systems, leads organizations to face new attack threats [START_REF] Wang | Measurement of Resilience and its Application to Enterprise Information Systems[END_REF].

Top Level Management Support

One important factor that most researchers agree must be adhered to in policy development is the support of top level management [START_REF] Von Solms | Information Security Governance: A Model based on the Direct-Control Cycle[END_REF] and [START_REF] Doughty | Implementing Enterprise Security: A Case Study[END_REF]. The best way to get employees to comply with information security policies is to engrain the policy into the organizational culture of the company. The overarching objective of information security management is to convert the organization's security policy into a set of requirements that can be communicated to the organization, measured, and imposed [START_REF] Tracey | IT Security Management and Business Process Automation: Challenges, Approaches, and Rewards[END_REF]. Basically, the better the top management support of information security, the greater the preventative efforts a firm (and its employees) will make [START_REF] Kankanhalli | An Integrative Study of Information Systems Security Effectiveness[END_REF]. Overall, top management support is essential to security governance success [START_REF] Da Veiga | An Information Security Governance Framework[END_REF].

Corporate Governance

The research of Weill and Ross [START_REF] Weill | A Matrixed Approach to Designing IT Governance[END_REF] on IT governance in 300 companies found that "IT governance is a mystery to key decision-makers at most companies" and that only about one-third of the managers' surveyed understood how IT is governed at his or her company (p. 26). Engulfing all of these methods for security protection is the idea of corporate governance. For information security, corporate governance is the way top level management and the board decide to run the IT department, and in turn, information system security. This is where the true decisions on how to attack a possible weakness are made. Solms [START_REF] Von Solms | Information Security Governance: Compliance Management vs[END_REF] posits that "Information Security Governance is now accepted as an integral part of good IT and Corporate Governance (Information Security Governance)." Khoo et al. [START_REF] Khoo | Information Security Governance of Enterprise Information Systems: An Approach to Legislative Compliant[END_REF] stated that information security governance is a subset of corporate governance that relates to the security of information systems, and because the board of directors is ultimately in charge of corporate governance information security must start at the top.

Implementation

The careful selection and implementation of security policies, standards and procedures will determine if the overall security program will support the organization's mission [START_REF] Peltier | Information Security Policies, Procedures, and Standards: Guidelines for Effective Security Management[END_REF]. So important is the implementation of these systems that national and international standards have been developed including ISO 27001, ISO 13569, GAISP (Generally Accepted Information Security Practices), and the Gramm-Leach Bliley (GLB) Act, among others [START_REF] Peltier | Information Security Policies, Procedures, and Standards: Guidelines for Effective Security Management[END_REF]. Sengupta et al. [START_REF] Sengupta | A Formal Methodology for Detecting Managerial Vulnerabilities and Threats in an Enterprise Information System[END_REF] affirms that ineffective implementation of security policy leads to weaknesses in enterprise information systems security.

Conceptual Fr amework

We have developed a conceptual model in Fig. 1 for EIS security that encompasses the major themes found in our literature review. This model is a slightly revised version of the conceptual model that was developed earlier [START_REF] Chaudhry | Enterprise Information Systems Security: A Conceptual Framework[END_REF], [START_REF] Chaudhry | Developing a Model for Enterprise Information Systems Security[END_REF]. In its simplest form, we draw the analogy that the company's EIS security is the roof that protects four main pillars: security policy, security awareness, access control, and top level management support (TLMS). Each of these pillars has an element of implementation required for sound EIS Security. The basic solid foundation of this 'house' is the company's corporate governance. These four pillars are the processes that management and the board of directors can choose to implement to make the system as secure as possible. Having all four pillars is the best way to make the enterprise information system secure, however removing any one of these columns can truly diminish the stability/security of the entire system. Below is a pictorial representation of the model.

Information Security in the Banking Sector

MWR Labs identified three banking sector security risks facing the industry and two of these, data loss prevention and identity & access management, are closely related to our model [35].The banking sector is governed by a regulatory framework to safeguard information. To highlight the regulatory governance of financial institutions to implement their information security, we briefly describe the role of the Federal Financial Institutions Examination Council (FFIEC) and the GLB Act.

Fig. 1. Conceptual model for enterprise information system security

The Federal Financial Institutions Examination Council

The FFIEC was established in 1979 and its primary goal is "[A]a formal interagency body empowered to prescribe uniform principles, standards, and report forms for the federal examination of financial institutions by the Board of Governors of the Federal Reserve System, the Federal Deposit Insurance Corporation, the National Credit Union Administration, the Office of the Comptroller of the Currency, and the Consumer Financial Protection Bureau" [36]. The FFIEC key areas to be addressed by financial institutions to implement information security measures [37] as 1) security process (e.g. governance issues); 2) information security risk assessment (e.g., steps in gathering information); 3) information security strategy (e.g., architecture considerations); 4) security controls implementation (e.g., access control); 5) security monitoring (e.g., network intrusion detection systems); and 6) security process monitoring and updating. The FDIC provides an outline of compliance issues related to the development and implementation of Information Security Program governed by the GLB Act in three key areas: involvement of the board of directors, assessment of risk, and managing and controlling risk [38]. The detailed security guidelines that banks are given to comply with the GLB Act center on [START_REF] Langin | Gramm-Leach-Bliley Security Requirements: Keeping Robbers and Regulators from the Door[END_REF]: 1) access controls on customer information systems; 2) access restrictions at physical locations containing customer information;

Enterprise Information System Security

3) encryption of electronic customer information; 4) procedures to ensure that system modifications do not affect security; 5) dual control procedures, segregation of duties, and employee background checks; 6) monitoring systems to detect actual attacks on or intrusions into customer information systems; 7) response programs that specify actions to be taken when unauthorized access has occurred; and 8) protection from physical destruction or damage to customer information.

Qualitative Analysis of Personal Interviews with Senior Information Officers in the Banking Sector

We validate the model through using key informant in-depth interviews and qualitative research methods. We interviewed senior information officers dealing with security aspects at four banking institutions in the Philadelphia area. Next, we present the highlights of these interviews with the senior information officers based on a content analysis of the themes in the interviews. It was quite surprising to learn from the interviews that all the four senior information officers in the banking industry agreed with the proposed conceptual security model. In addition, they all rated the four pillars of security policy, security awareness, access control, and top level management support as being extremely important for their organizations.

Under the security policy pillar, three of the four officers stated that another key element is the training of the employees. Other key elements related to security mentioned by the senior information officers include the training of top-level management and simplifying the communication of the policy to all levels of the organization.

Some of the most important aspects associated with security awareness mentioned by the senior information officers were using third-party audits to test the system and to provide training with minimal technical jargon during the training sessions.

For access control, the overarching element mentioned by all four senior information officers was the development of sophisticated measures to limit access. In addition, other key elements included avoiding carte blanche access to any employee and requiring the employees to 'sign off' on greater security privileges.

In regards to the most important elements of top level management support, all four senior information officers stated that top level management involvement is required due to stipulations imposed by the regulatory bodies in the banking sector. One manager stressed that overseeing the implementation of the system was a key role of top management at his financial institution.

We identified four major themes that impact the security issues within firms. These four factors are identified as security policy documentation, access control, employee awareness, and top level management support. Based on these factors, a conceptual framework based on relevant literature was presented within the context of corporate governance for enterprise information systems. To test the framework, in-depth interviews with IT officers using a cross-section of companies in the banking sector were used to confirm the model. In the future, we will administer a survey instrument to a larger population of IT officers to further study the various issues that have been exposed in this research within the context of enterprise information systems security.


Suzana De França

Dantas Daher

Adiel Teixeira De Almeida

Group Preference Aggregation based on ELECTRE Methods for ERP System Selection

Keywords: Group preferences, multicriteria decision aid, ELECTRE II, ELECTRE IV, ERP selection

The ability of enterprise information systems, such as enterprise resource planning (ERP), manufacturing executive systems (MES) and customer relation management (CRM), to improve production and business performance are demanding more attention from enterprises, since increase in competitive advantages is a goal to be reached. Integration of all the information flowing through a company is a key characteristic of ERP systems. Enterprise systems are not developed in-house and so, in order to implement an ERP project successfully, organizations must purchase ERP systems which can be aligned with their needs. In a group decision context where all opinions and preferences must be taken into account, choosing the most suitable alternative may be a hard work. In this study, a group preference aggregation approach based on a combination of ELECTRE II and ELECTRE IV method is presented within the context of ERP project selection.

Introduction

It is well known that market competition transforms the way in which companies deal with their business and organizational environments. Companies are looking for tools, methodologies and operational policies that support them to reduce total costs, maximize return on investment, shorten lead times and be more responsive to customer demand [START_REF] Wei | An AHP-based approach to ERP system selection[END_REF]. An Enterprise Resource Planning (ERP) system is an Enterprise Information System (EIS) designed to improve operational efficiency and enhance organizational performance. An ERP improves operational efficiency by integrating business processes and providing better access to integrated data across the entire enterprise, while to enhance business efficacy, means that a company may review (or redesign) its business practices by using an ERP [START_REF] Chou | The implementation factors that influence the ERP (enterprise resource planning) benefits[END_REF]. Integrating business processes means fostering a seamless integration of all the information flowing through a company, including financial and accounting; human resource information; supply chain information and customer information [START_REF] Nah | Critical factors for successful implementation of enterprise systems[END_REF][START_REF] Davenport | Putting the enterprise into the enterprise system[END_REF].

Deciding which is the most suitable ERP solution is often a difficult task for many companies. Therefore, decide among preselected alternatives using crite-ria that sometimes conflict with each other, based on the enterprise s needs, has led researchers to investigate better ways to evaluate and select ERP systems. Several studies have been conducted to identify models and methodologies to support decision makers in making technology acquisitions, including in the selection of software packages. Within the context of using a multicriteria decision making for this, some papers use analytic network process (ANP) and analytic hierarchy process (AHP) approaches [START_REF] Wei | An AHP-based approach to ERP system selection[END_REF][START_REF] Liang | Enterprise information system project selection with regard to BOCR[END_REF][START_REF] Jadhav | Evaluating and selecting software packages: A review[END_REF] to select an ERP. For the same purpose, it is possible to find combinations of these methods with Delphi Methods and goal programming [START_REF] Lee | An integrated approach for interdependent information system project selection[END_REF] and by using an artificial neural network and an ANP [START_REF] Yazgan | An ERP software selection process with using artificial neural network based on analytic network process approach[END_REF]. A combination of a quality function deployment (QFD), fuzzy linear regression and zeroone goal programming to develop a framework for an ERP system selection can be found in [START_REF] Karsak | An integrated decision making approach for ERP system selection[END_REF]. Fuzzy approaches [START_REF] Lee | A fuzzy multiple criteria decision making model for software selection[END_REF] some of which are combined with rough set and TOPSIS methods [START_REF] Huiqun | ERP software selection using the rough set and TOPSIS methods under fuzzy environment[END_REF] have been adopted for a selection problem. Data Envelopment Analysis (DEA) approach has also been applied to the process of selecting an ERP system [START_REF] Lall | Enterprise Resource Planning (ERP) System Selection: A Data Envelopment Analysis (DEA) Approach[END_REF]. Outranking methods such as ELECTRE [START_REF] Wu | Using multiple variables decision-making analysis for ERP selection[END_REF] and PROMETHEE [START_REF] Rao | Software Selection in Manufacturing Industries Using a Fuzzy Multiple Criteria Decision Making Method[END_REF] are also found in the literature.

Organizations select and implement ERP systems so as to obtain a variety of tangible and intangible benefits and for strategic reasons. The evaluation process of ERP systems needs to take many criteria into account [START_REF] Olson | A combined method for evaluating criteria when selecting ERP systems[END_REF] which include organizational factors such as the complexity of the business; dealing with change management, cost drivers, its functional requirements, system flexibility, system scalability, and also external factors such as its relationship with supply chain partners, and the pressure of value networks may affect the ERP selection process [START_REF] Haddara | ERP Systems in SMEs: A Literature Review[END_REF]. A multicriteria decision making must consider such diversity in order to better evaluate the alternatives.

Although most studies are conducted based on a single decision maker (DM), there is a strong possibility that in several organizations, an ERP system will be selected by a group. Multicriteria group decision making involves individuals who provide their preferences for a set of alternatives with respect to a set of attributes [START_REF] Daher | The use of ranking veto concept to mitigate the compensatory effects of additive aggregation in group decisions on a water utility automation investment[END_REF]. Diverging opinions may arise since DMs have their own unique characteristics with regard to their knowledge, skills, and personality. Group decision making involves two or more decision makers who take responsibility for the choice. This study deals with how support a group of individuals to achieve a collective decision when selecting an ERP system. The methodology adopted considered that DMs act in accordance with their own interests and there is no information about their relative importance to each other [START_REF] Alencar | A Multicriteria Group Decision Model Aggregating the Preferences of Decision-Makers Based on ELECTRE Methods[END_REF]. Group decision making has a wide diversity of applications and has been the study focus of several research studies which is indicative of its relevance [START_REF] Brito | Multi-criteria Decision Model for Selecting Repair Contracts by applying Utility Theory and Variable Interdependent Parameters[END_REF][START_REF] Daher | A combination of ranking veto concept and distance measures to minimize conflicts in a group decision problem[END_REF][START_REF] Morais | Group decision making on water resources based on analysis of individual rankings[END_REF][START_REF] Leyva-López | A new method for group decision support based on ELECTRE III methodology[END_REF].

This study sets out the methodology proposed by [START_REF] Alencar | A Multicriteria Group Decision Model Aggregating the Preferences of Decision-Makers Based on ELECTRE Methods[END_REF] based on a combination of ELECTRE II and ELECTRE IV methods. The most widely used method in outranking methods is ELECTRE [START_REF] Roy | The outranking approach and the foundations of ELECTRE methods[END_REF]. Outranking methods are particularly suitable for decision-making through the notion of weak preference and incomparability [START_REF] Figueira | Multiple criteria decision analysis: state of the art surveys[END_REF].

The remainder of this paper is organized as follows. Section 2 presents the model proposed and Section 3 describes a numerical application to illustrate the applicability of the model in the context of selecting an ERP system. The final section gives the conclusions of the study.

Model proposed

ELECTRE is a family of multicriteria decision analysis methods and its acronym stands for ELimination Et Choix Traduisant la REalité [START_REF] Roy | The outranking approach and the foundations of ELECTRE methods[END_REF]. This family seeks to obtain a set of N alternatives that outrank those which do not belong to the subset N. ELECTRE assumes that DMs are able to provide intercriteria information, which reflect the relative importance among the k objectives (criteria weights).

The model proposed assumes that the decision problem is well structured and a set A of n alternatives and a set C of k evaluation criteria are also prior defined. A decision matrix D = [d ij ] nxk can be defined for each DM, in which the element dij represents the performance evaluation of the alternative a i in accordance with criterion C j . Note that if m DM exists, m decision matrices (n x k) are established.

This model includes the aggregation of individual priorities and a combination of ELECTRE II and ELECTRE IV methods [START_REF] Alencar | A Multicriteria Group Decision Model Aggregating the Preferences of Decision-Makers Based on ELECTRE Methods[END_REF] and is organized in three steps. The first step involves ELECTRE II so as to generate individual rankings of alternatives. The outranking relation is built by using concordance and discordance indices. Where g j (a) denote the evaluation of action a on criterion g j , for all a ∈ A and j ∈ C. In the second step of the evaluation, all individual rankings are brought together to create a global matrix of preferences (n x m) and, the third step is for aggregating all individual preferences by using the ELECTRE IV method. According to [START_REF] Vincke | Multicriteria decision-aid[END_REF], ELECTRE IV was developed so as to rank actions without introducing any weighting of the criteria. This method is suitable for the last step of the model proposed since all DMs are considered to have the same weight. Note that ELECTRE IV is used in cases in which there is a pseudocriterion family and its main feature is the absence of a weighting related to the relative importance of the criteria.

3 Selecting an ERP system: a numerical application In this section, a fictitious case study was drawn up using ERP characteristics found in the literature to illustrate how the proposed model can be applied to selecting an ERP system for a Brazilian airline. Air services for the transport of passengers and freight is a highly competitive market and the need for useful tools and techniques to reduce costs and improve operational efficiency seems absolutely vital if an organization is to be competitive.

This company has to deal with inefficient operational procedures and an IT/IS legacy system. In order to improve its competitiveness, senior managers have announced the launch of several projects including an ERP system and the reengineering of complex business processes with a view to enhancing the effectiveness of its operational procedures and to responding better to its customers demands.

Four decision makers are involved in the ERP selection process: the financial manager (DM1), the IT/IS manager (DM2), the operational manager (DM3) and the customer relation manager (DM4). These DMs are also responsible for deciding on and accepting the evaluation criteria for the selection process. An analyst should conduct the evaluations of the criteria.

ISO/IEC 9126-1 is a standard that addresses quality model definition and its use as framework for software evaluation. Therefore criteria for software projects are usually established based on this standard. However it is possible to organize criteria according to other aspects and a more complete list of criteria can be found at [START_REF] Jadhav | Evaluating and selecting software packages: A review[END_REF]. Table 1 presents the selected criteria for this case study. Four ERP system alternatives (A1, A2, A3 and A4) are considered for this problem. All criteria and alternatives are acceptable to all DMs.

Decision model first step: individual rankings. The first step of the model comprises defining individual preferences by obtaining a preorder from each DM. The evaluation matrix is the same for all DMs since there is no modification as to evaluating the ERP products in each criterion for each DM. The evaluation matrix is shown in Table 2 and the concordance and discordance coefficients with their corresponding parameters for each DM are presented in Table 3.

The criteria weights (inter-criteria information) of each DM are shown in Table 4.

ELECTRE II is run using the data from the above tables. Table 5 summarizes the preorders obtained for each DM after the application of the method.

Decision model second step: obtaining a matrix of global evaluation. In this step, the analyst must collect all individual rankings and compile them in a global evaluation matrix. For this matrix, DMs are considered as criteria and their rankings correspond to the evaluations of the alternatives. The higher the numerical evaluation of an alternative is, the better its position in the preorder, as shown in Table 6. Decision model third step: obtaining a group ranking. Given that there is no intercriteria information, ELECTRE IV could be applied and the following ranking is obtained (Table 7). Note that since the evaluation of an alternative corresponds to its position, any difference between alternatives implies a strict preference. Some incomparability occurred among A1, A3 and A4. Therefore, alternative A2 which was ranked in first place is the one selected. Actually in this numerical problem, alternative A2 is a consensual alternative since it is considered as the best option by all DMs. If two or more alternatives are ranked equal first in the ranking, the DMs must review their preferences in order to achieve a group final recommendation for only one of them.

Final remarks and conclusions

ERP Systems have an extremely important role in helping organizations to realize their corporative strategic planning goals. Companies are looking for tools, methodologies and operational policies that support them to reduce total costs, maximize return on investment, shorten lead times and which will help them be more responsive to customers demands. However, during the ERP selection and implementation process they may well also incur high costs and face potential high risks. This study presents an approach to support a group of decision makers to select an ERP system for a Brazilian airline. The model proposed combines two ELECTRE methods (ELECTRE II and ELECTRE IV). ELECTRE II was used to provide individual rankings of alternatives and ELECTRE IV to generate a global ranking using an approach that aggregates individual priorities.

An important observation to be made is that different results could appear if in the last step of the model proposed, the ELECTRE IV method should be changed to another other method such as the Borda Count or Condorcet. This modification is possible since it is not necessary to evaluate weights given by DMs. However, the analyst must consider the fact that these methods are based only on positions in the ranking (the Borda Count is a positional voting method while Condorcet performs a pairwise comparison of alternatives to identify the preference of the majority of the DMs) and consequently provides less information to the selection process.

  A concordance index C(a,b) represents the coalition of arguments in favor of the statement "a is at least as good as b" or in other words "a outranks b". A discordance index D(a,b) is used to measure the arguments that may cast some doubt upon the latter statement. These indices are used to construct two pre-orders based on a strong (a S S b) outranking relation and a weak outranking relation (a S w b). Finally strong and weak rankings are deduced to obtain the final ranking for each DM. The outranking relations (strong and weak) between two alternatives a and b are presented as follows [23]: a S s b ⇐⇒ ,b) ≥ c + D(a,b) ≤ d + j:gj(a)>gj(b) w j > j:gj(a)<gj(b) w j ,b) ≥ c - D(a,b) ≤ d - j:gj(a)>gj(b) w j > j:gj(a)<gj(b) w j (2)

Table 3 .

 3 Concordance and discordance coefficients for each DM c + c -d + d -

Table 1 .

 1 Criteria adopted for selecting an ERP system

		Criteria	Criteria group Meaning of the criterion
	C1	Completeness	Functional This is defined as the degree to which the
				software satisfies the functional
				requirements (uses a 5-level ordinal scale)
	C2 Number of simultaneous Functional Number of simultaneous users that can
		users		be linked to and served by the system
	C3	DBMS Standards	Portability Breadth of database management
				systems that can be accessed by the
				software package
	C4 Number of modules Maintainability Average size of independent code units
	C5	Time behavior	Efficiency	Ability of the software package
				to produce results in a reasonable amount
				of time relative to the size of the data
				(in milliseconds)
	C6 Length of experience	Vendor	Experience of vendor in developing
				software products (uses a 5-level ordinal
				scale)
	C7	License cost	Cost	License cost of the product in terms of
				number of users (in monetary units)
	C8	Installation and	Cost	Cost of installing and implementing
		implementation Cost		the product (in monetary units)

Table 2 .

 2 Decision matrix

	C1 C2 C3 C4 C5 C6 C7 C8
	A1 4 5000 4 8 0.

Table 4 .

 4 Normalized weights of each DM s criteria

	C1 C2 C3 C4 C5 C6 C7 C8
	DM1 0.175 0.175 0.082 0.221 0.043 0.117 0.093 0.094
	DM2 0.081 0.101 0.086 0.333 0.005 0.081 0.188 0.125
	DM3 0.102 0.004 0.005 0.200 0.136 0.149 0.370 0.034
	DM4 0.035 0.035 0.198 0.167 0.056 0.232 0.211 0.066

Table 5 .

 5 Table of preorders for each DM

	Ranking DM1 DM2 DM3 DM4
	1 st	A2 A2 A2,A4 A2
	2 nd	A3 A3	A3	A3
	3 rd	A1 A1	A1 A1,A4
	4 th	A4 A4

Table 6 .

 6 Matrix

		of global evaluation
	DM1 DM2 DM3 DM4
	A1 2	2	2	2
	A2 3	3	4	3
	A3 1	1	3	1
	A4 4	4	1	4

Table 7 .

 7 Global ranking of alternatives

	Ranking Alternatives
	1 st	A2
	2 nd	A1, A3, A4

Acknowledgment This study is part of a research project funded by the Brazilian Research Council (CNPq). The authors also acknowledge the financial support given by CAPES.