Chong Wang
email: cwang@sklse.org

Lai Xu

Paul De Vrieze
email: pdvrieze@bournemouth.ac.uk

Peng Liang
email: liangp@sklse.org

Process Modeling for Internet Scale Virtual Enterprise Collaborations

Keywords: Internet scale business process, Business process modeling, Virtual enterprise process collaboration, Web-scale workflow

The ever-increasing need for flexibility of business collaborations that ultimately involve a large number of virtual enterprises puts demands on their design. Competitive markets require the collaborations to be highly agile, effective, and efficient. This paper defines Internet scale virtual enterprise collaborations (ISVECs) as well as their characteristics. We further present a process modeling method for Internet-based virtual enterprise collaborations. An end user process modeling language of ISVECs and a meta-model of the language are provided. Finally, we demonstrate how the method and language are used.

Introduction

In recent years, the service-oriented architecture paradigm has provided an easy approach to software development. Virtual enterprise systems are increasingly depending on and functioning as driver for the development of large scale distributed applications by reusing services [START_REF] Papazoglou | Service-oriented Computing[END_REF].

Internet scale virtual enterprise collaborations (ISVECs) are business collaborations among virtual enterprises. This normally involves great numbers of services available through the Internet. These services should be annotated with semantic descriptions enabling dynamic selection, resource binding, and verification. As the services are provided by different providers, there is a strong likelihood that some of these services are modified, substituted, or disappear. Different versions of the services may include different features or have incompatible semantics. The services can be invoked from outside their own infrastructure, i.e. from a business partner's site. The semantic annotations can help detecting these changes and provide an early warning when the changes are incompatible.

Internet scale virtual enterprise collaborations are possible due to service that exist both inside and outside a virtual enterprise. Any ISVEC architecture should be a service-based development approach with a range of services that represent capabilities across a wide variety of domains.

As a business environment changes rapidly, the ability to set up a collaborative business process in a virtual enterprise is desirable [START_REF] Xu | Lightweight Process Modelling for Virtual Enterprise Process Collaboration[END_REF]. Collaborative business processes are increasingly driven by business agility, adaptability, and flexibility, particularly in a virtual enterprise environment. There is increased pressure to build enterprise applications quickly in order to respond to situational needs of the business.

In this paper, we deal with lightweight business process modeling issues. We start with a motivating example. We define a lightweight business process modeling language and provide its meta-model. The paper also uses the lightweight business process modeling language to model a motivating example. Finally, conclusions and future research are presented.

Motivating Example: Internet Moving Services (IMS)

As a motivating example we introduce a hypothetical international moving service. An international moving service aims to facilitate international relocations in various ways. These services go beyond moving items and can include things such as visa applications and assistance in finding a new residence. In brief, the goal of international moving services starts with helping customers to find moving companies and request quotes, but extends to many aspect of managing an international relocation. A very brief, incomplete and abstract description of the various services offered by an international moving service includes: • Find moving companies: compare the services of international movers by requesting free quotes for the customer; provide moving tips, and information documents needed for international moving such as official government customs, visa and immigration, health, weather, etc. • Travel arrangements: find cheapest tickets and/or car renting in both places of departure and destination if needed. • Temporary stay arrangement: find hotels or holiday/serviced apartments in both the departure location and the destination if needed. • Home search: pre-select properties according to client requirements such as proximity to a childcare centre and provide neighborhood guide which contains information on doctors, shopping, schools, leisure activities etc. • School/childcare search: provide explanation of the local education system, options including public, private and international schools, provide information on preschool options including nurseries, toddler groups and other childcare facilities, provide list of possible schools, childcare or other facilities relating to the home search area. • Settling-in services: advice on banking systems, provide information on insurance of health, home, car etc., and advise on importing a car into the destination if applicable. • Leaving assistance: arrange property hand-back or sale, close utility accounts and arrange final bills, and manage property if client leaves before end of tenancy. We have found the following available Web services, feeds, widgets, and mashups from websites like syndic8.com and programmableweb.com. A list of available feeds, Web services, widgets, gadgets, mashups that can be used as components in implementing the example:

1. Moving company feeds from 123movers. 2. Moving tip feeds from 123movers. Both Feeds 1 and 2 can support the service of "find moving companies" 3. SmartTravelDeals: publishes the best travel deals on the web. It publishes current travel offers to worldwide destinations and connects users to the direct booking path. 4. Hotwire Travel-Ticker Deals: connect with more than 10,000 travel companies. The deals can be sceached by destination, theme, dates, or price. Both API 3 and 4 sustain the service of "travel arrangements" 5. Cleartrip Hotel API: provides booking for flights, hotels and trains, as well as other travel services across the world. 6. Active.com Camping API: provides access to campground data for 97% of the US and Canada's national and state/provincial parks. 7. HomeFinder.com connects home buyers, sellers and real estate professionals through local newspapers' online real estate section. 8. ImmobilienScout24 API provides rental listings, house listings, and building construction information from Germany. 9. PeekaCity API: using google street view for neighborhood amenities which is used primarily by real estate agents as a service to their customers (currently in Chicago and Dallas/Fort Worth). 10. Easy one loan and home values: mashup of zillow and yahoo maps as supplement to online mortgage service.

Above five APIs can be included to implement the service of "temporary stay arrangement"; API 5,7,8, 9 and 10 can be used for the service of "home search".

11. Child care finder mashup: find babysitters, nannies, and other care options visually with google maps 12. California school finder mashup provides information such as, the school rankings, course offerings, and other details. 13. Childcare position offered in France. 14. Feed Childcare position wanted in France Above API 9, Mashup 11 and 12, and Feed 13 and 14 can be applied to implement the services of "school/childcare search". 15. NHS Choices has created a set of web services to allow approved partners to interact with the service, free of charge. 16. Patient Opinion is a UK organization that collects patients' opinions about heath care and treatments they have recently received. 17. Hospital Compare API allows developers to get various hospital information like addresses, mortality rates, prices for operations and other hospital-related data. 18. Monster Web Services Toolkit API allows users to publish job ads to the Monster.com job search and placement service. Monster service includes job seeking, career management, recruitment and talent management products and services.

Above APIs and Mashups are useful for the "settling in service".

19. Home value calculator: uses zillow data to calculate the value of single family homes in the U.S. Small widget suitable for placing on your google home page. It is a useful mashup for the service of "leaving assistance"

In this example case, it will be expensive and difficult to build a traditional workflow system to support the business process. Doing so would mean that either all information would have to be known in advance or an interface would need to be provided to add information to the traditional workflow solution. Few relocations would be exactly alike even though aspects could be shared. The dependences are various, such as finding a home close to the best school or the available childcare, find the good schools close to the home address. It would however be handy for a business process mashup solution, specially, if automatically invocation of needed feeds, Web services, etc. and execution processes are supported. The different processes of IMS can be implemented by different process instances. Users (i.e. owner of IMS) may only need to edit the certain processes to be able to meet all requirements from new customers.

Meta-model of the ISVECs Language

In this section, we introduce the meta-model of the ISVEC language which the end users can use it to establish the business processes mentioned in Section 2. The notations of the ISVEC language are presented in Figure 1. Eight symbols are adopted from BPMN [START_REF]BPMN[END_REF]. The choice of BPMN as basis is motivated by its wide acceptance within the business world. Other alternatives may offer different advantages for different user groups. The ISVEC language is based on workflow patterns [START_REF] Xu | Lightweight Process Modelling for Virtual Enterprise Process Collaboration[END_REF]. Adoption of different notations should not change the semantic of the languages. Since the process model is finally mapped into concrete services, we introduce new notations in the form of goals, which will allow business users to define abstract and user-friendly processes. Goals are the representation of an objective in which fulfillment is sought through the execution of a possibly complex service. The goals are always associated with an activity or process. We define two types of goals: atomic goals and composite goals. Atomic goals are associated with a single concrete Web service or computing resource, involving just one step of computation. Composite goals involve other simpler subgoals for fulfillment. In practice, if a process or activity is a process associated with a complex goal then the process or activity is fulfilled by achieving other goals, or invoking composite concrete Web services or computing resources. Hence, there are, in total, ten notational symbols within our lightweight process modeling language. This minimal subset of notation means a user will have reduced learning, whilst, we contend, still providing sufficient expressive power.

Figure 2 provides a meta-model for the control flow of the lightweight process modeling language. The meta-model describes the relationships among all elements within the process model, namely 'start', 'end', 'activity', 'sequence flow', 'exclusive gateway', 'parallel gateway', 'inclusive gateway', 'atomic goal', and 'composite goal'. An abstract concept 'gateway' is used as a super set of three gateways. An 'atomic activity' is the smallest unit of activity, e.g., a concrete Web service or a computing resource. A 'composite activity' consists of several other activities, either atomic or composite. An 'activity' is either an 'atomic activity' or 'composite activity'. The terms 'process pattern' and 'process template' are explained [START_REF] Xu | Lightweight Process Modelling for Virtual Enterprise Process Collaboration[END_REF], and 'flow object' in the figure represents a process model. We separate 'non sequence flow object' from 'sequence flow', to ensure the alternating ordering of 'sequence flow,' i.e., arrows and other objects, and thus avoid the situation where two 'sequence flow' elements link directly to each other.

Model of the motivating example

An overview of the services for Virtual Enterprise-Internet Moving Services (VE-IMS) can be found from Figure 3. Being a VE-IMS, the payment, CRM, and bookkeeping functions that should be included for being a normal business are sourced from third parties. However, we only concentrate here on the VE's core business processes. General business related processes are not discussed here.

Figure 3: Meta level services of the VE-IMS

Because of the various requirements from its customers, the services provided by a VE-IMS are dependent on the particular situation of its customers. Different customers require a different process. This process is supported by a special-purpose piece of software, which we call an business process mashup, with particular services, processes or activities. In addition to the added capability, new business process mashup can modify, enhance, customize or extend an existing service mashup, or include and combine parts or components (or both) from multiple existing service mashups.

A preliminary service of the VE-IMS is to help customers to find a moving company for shipping their household effects to the new place of residence. Figure 4 shows the process of the finding a moving company. First, the VE-IMS will request free quotes from moving companies according to the customer's place of departure and destination, and if needed, arrange for visits, and provide a list of competent movers with their quotes.

Figure 4: Subprocess of finding a moving company

Another, extended, service the VE-IMS may provide is finding an international mover and arranging temporary places of residence at both the locations of departure and destination, based on the dates of moving, travel, and the arrival of the household effects. The temporary place of residence at the destination should be close to a certain address such as the customer's working place. Customer can also ask for travel arrangements to be made. The time to fly and time of staying at the temporary address should be worked out to minimize the total costs. Further, the customer may want the VE-IMS to find an available childcare place for the children of the customer as soon as possible, then find a rental home close by around the time that the household effects arrive. The second extended international moving service is shown in Figure 5. Lightweight and user friendly process modeling is one of issues at a design stage. Process modeling further effect to service description and process execution.

Lightweight process modeling language is designed for process oriented business [START_REF] Xie | Lightweight Business Process Modelling[END_REF]. The language is designed for business users who do not have deep business process design knowledge. It requires the process mashup engineer who could map the abstract activities into the concrete services. Our modeling language for ISVECs is based on the lightweight business process modeling language [START_REF] Xie | Lightweight Business Process Modelling[END_REF] and lightweight process modeling for virtual enterprise process collaboration language [START_REF] Xu | Lightweight Process Modelling for Virtual Enterprise Process Collaboration[END_REF]. It provides strong end user aspects on business flexibility, adapbility and agility. The Internetscale virtual enterprise collaboration is therefore different with an approach mentioned in Internet-scale workflow [START_REF] Tretola | Autonomic internet-scale workflows[END_REF]. The process mashup engineer will discover services and map abstract process activities into concrete services [START_REF] De Vrieze | Building enterprise mashups[END_REF].

Similarly, the concept of instant virtual enterprises (IVEs) is introduced in [6] to dynamically select collaborating partners and weave the interorganisational links between their local processes. Moreover, CrossWork system is developed to create and operate IVEs by decomposing high-level goal into a set of operational business goals, identifying collaboration partners that can fulfill the goals, retrieving the external specifications of selected local process, and finally mapping the composed global business process onto the IVE's distributed infrastructure and executes it there. Different from creating IVEs, our approach concentrates on the business collaborations among virtual enterprises. Particularly, it proposes a lightweight process modeling language and the corresponding metamodel to create the Internet scale virtual enterprises collaborations, and introduces goals to help business users define abstract processes and finally map them into concrete services available on the Internet.

Conclusions

Internet scale workflows put more demands on process modeling. Multiple service providers are generally involved, and their actions are largely independent and outside control of the process owner, services can suddenly change because of new versions. Networking issues can make services temporarily unavailable or have unacceptable latencies.

Virtual enterprises have a strong advantage in business agility. Their small size and loose ties with partners make that they are not held back by large bureaucracies. They depend on tight integration with suppliers of various services. Internet and automation enable this integration. Automation of business processes is generally provided by business process management systems. For virtual enterprises to be able to quickly respond to changing business environments they therefore need agile business process support.

Agile business process support has two parts. The first part is run-time support for change on-the-fly, a topic not discussed in this paper. The second part is to make it easy to change business processes. To enable business process agility modification of processes should be possible by a broad set of stakeholders, not only by business process specialists as an extra link in the chain.

Business process mashups [START_REF] De Vrieze | Building enterprise mashups[END_REF] are designed to provide agility, resilience and end user modifiability. Therefore, they are a good candidate to support internet scale virtual enterprise collaborations.

Figure 1 :

 1 Figure 1: Notations of Lightweight Process Modeling Language

Figure 2 :

 2 Figure 2: Meta-model of Lightweight Process Modeling Language

Figure 5 :

 5 Figure 5: Processes for the extended VE-IMS

7 Acknowledgement This research project is supported by the National Basic Research Program of China (973) under Grant 2007CB310801, the National Natural Science Foundation of China under Grant No. 60970017, and the Fundamental Research Funds for the Central Universities under Grant No. 3101032. The authors would like to thank the EU SOA4All and FAST projects. Part of work by Dr. Lai Xu and Dr. Paul de Vrieze was performed at the SAP Research, Switzerland.


Luis M Camarinha-Matos

Hamideh Afsarmanesh
email: h.afsarmanesh@uva.nl

Bernhard Koelmel
email: bernhard.koelmel@cas.de

Collaborative Networks in Support of Service-enhanced Products

Keywords: Collaborative networks, Service-enhanced products, Collaborative Ecosystems, Cloud computing

The development and support of highly customized and serviceenhanced products requires new organizational structures, involving the manufacturers, customers and local suppliers in a process of co-creation. This requires the implementation of the glocal enterprise notion with value creation from global networked operations and involving global supply chain management, product-service linkage, and management of distributed manufacturing units. An approach based on cloud-computing and advanced collaboration spaces is proposed for such contexts. As application scenario the manufacturing and life cycle support of solar parks is considered.

Introduction

There is a growing trend in manufacturing to move towards highly customized products, ultimately one-of-a-kind, which is reflected in the term mass customization. In fact, mass customization refers to a customer co-design process of products and services which meet the needs/choices of each individual customer with regard to the variety of different product features [START_REF] Cox | Consumer-driven innovation networks and e-business management systems[END_REF], [START_REF] Ogawa | Collective Customer Commitment: Reducing the risks of new product development[END_REF]. Important challenges in such manufacturing contexts can be elicited from the requirements of complex technical infrastructures, like security infrastructures, alternative energy, or illumination systems in large public buildings or urban equipments, but also in more traditional complex products such as customized kitchens:

These products typically require a variety of competencies and resources, hardly available in a single enterprise, which calls for collaboration among several companies and individuals. In many cases operations are performed within a fixed solution space, characterized by stable but still flexible and responsive processes, which can highly benefit from ICT support. As a result, the costs associated with customization allow for a price level that does not imply a switch in an upper market segment.

A complex multi-supplier product with a high degree of customization would benefit from associated services (e.g. maintenance support, assistance wizard, etc.) leading to the notion of service-enhanced products, which are more difficult to plan and arrange than with standardized mass products. Customization demands that the recipients of the customized goods transfer their specific needs and desires into a concrete product specification. This calls for customers' integration into the value creation process to detailed defining, configuring, matching, and/or modifying an individual solution. Different from a do-it-yourself setting this is done in close interaction between the manufacturers and the customer, who will contribute to co-creating the product/service with the manufacturer (or provider) responsible for providing the customized solution.

From a strategic management perspective, mass customization is a differentiated strategy. Customers gain from the customization of the increment of utility and variation of a good that better fits to their needs than the best standard product attainable. The larger the heterogeneity of all customers' preferences, the larger is this gain in utility and variation. From a managerial point of view, customization can be carried out with regard to fit, style, functionality, etc. Matching the level of customization offered by a manufacturer with the customers' needs becomes a major success factor. Providing European SMEs with adequate ICT support environments for mass customization therefore gives them a leading edge over other competitors from others regions that are more competitive in mass production of standardized products.

Overcoming the economic crisis requires companies to focus on exporting, namely to act in emerging markets such as the BRIC (Brazil, Russia, India, China), which is difficult for SMEs to compete in, if working alone. In this context, many enterprises are struggling to survive in the currently turbulent markets, whilst some become leaders in gaining new markets and effectiveness by targeting their future in terms of new products and services, or some other emerging technologies, having their focus already on technical innovation and strong customer-orientation. When focusing on customizable complex products, a domain where European companies might have an opportunity, it is important to be aware of the socio-economic, traditional, cultural, and perhaps even religious context surrounding the customer. A collaborative network involving not only a network of European manufacturers, but also the customer and some local suppliers is thus beneficial and necessary. Since the main customers of complex products and technical infrastructures are public entities, it is even frequently the case that the collaboration with local suppliers is a contractual requirement.

This paper introduces the base concepts and preliminary results of the GloNet project which aims the development of the required support platforms interlinked with the development of adequate organizational and governance models to facilitate the rapid formation and effective operation of the described partnerships.

A Motivating Case

The industry-driving use case in GloNet is in the Solar Park construction sector. The norm of operation in this industry is that of one-of-a-kind production and delivery of products (e.g. infrastructure, photovoltaic panels, and control systems). The results (products and services) are typically delivered through complementary competences sharing between different project participants. Such operational modes naturally have implications on the way the Product Lifecycle Management (PLM) is organized between the participating organizations.

As energy costs continue to rise, businesses need smarter energy management strategies. Advances in control technology give the benefits of energy management and control systems in a single, sustainable, and flexible networked infrastructure. During a product development process, it is essential to identify the critical components, critical suppliers and also the proportion of commodities to be outsourced to each supplier, thereby deciding on the structure of a virtual enterprise of involved companies.

The Infranet Partners is a network of SMEs specializing in the control technology solutions based on production and provision of advanced control technologies. This network was established in 1999 with 4 founding members and today there are some 20 partners in this network. In photovoltaic solutions around the world, products from the Infranet Partners are used to monitor and control solar park units and their related processes.

Solar parks include a number of subsystems -security, lighting, elevators, power, safety, and HVAC (Heating, Ventilating, and Air Conditioning) -that are crucial to a well-run system. But most of them operate separately or, at best, are connected through a series of costly, hard-to-maintain gateways to a single humanmachine interface. The Infranet Partners invested on the concept of open control systems, where manufacturers follow independently maintained interoperability guidelines that create a single, unified automation system. Embedded technology and infrastructure products are at the heart of these open systems.

Aiming at a new generation of systems, integrating remote support services, and in order to better serve customers, the Infranet Partners aim to improve their current operation as a collaborative network, through:

Creating a comprehensive pool of Technology and Application resources.

Serving the customers as a single organization, offering locally adapted solutions from this shared pool. Answer the demand for holistic user-centered solutions (customers demand "complete" solutions out of one hand). Focusing on core competencies of each partner in the virtual enterprise: delegating the process of value generation into the supply chain.

Combining their products range under the Infranet Partners brand and providing services associated to the products along their life cycle. Providing a comprehensive product range and support backed by frequent cross training.

Sharing technical support and knowledge of different markets to provide solutions for customers. Sharing marketing information using an advanced dynamic groupware marketing tool to enable them to act faster to meet customer requirements. Reaching a smooth collaboration environment involving customers and local suppliers in their target market locations (e.g. India). Example services associated to the product life cycle include:

-Remote monitoring and diagnosis -Remote supervision -Predictive maintenance -Product usage: training, assistance, interaction. Market drivers in complex industrial infrastructures like solar plants come with increased usage of controlling software and electronics as a distinguishing feature, coupled with changes in manufacturing such as globalization, increased competition, higher safety needs and faster serviceability. This has led to challenging new requirements for content-rich and price-competitive products. In this domain, the latest product developments incorporate new intelligent features with increasing complexity and the use of services, electronics and software as differentiators in the marketplace. These features require added manufacturing know-how along the value chain to drive the next level of operational efficiency and performance. The development of these complex interlaced systems over the entire product lifecycle represents an increasing challenge for all manufacturers and their suppliers.

As such, the following are some challenges faced by the manufacturers within the planned GloNet Virtual Enterprise:

Mechanical, construction, electrical, and software product development have traditionally grown up as separate silos of expertise and technology that need to be brought together early in the development lifecycle of the product. Furthermore clients of such one-of-a-kind production industry demand user-centred customised products and services that a single organisation may not be able to deliver. GloNet is developing a platform, tools and governance principles to support effective creation and operation of the virtual enterprise and its interaction with the customer.

There is no single management system for capturing product data at network level. Mechanical, electrical, and software data are often handled in separate document management systems with no automated sharing of data between the systems or links between data. With GloNet, all relevant documents can be stored centrally and called upon via web-service APIs, providing a single source of all productrelated information along its life cycle. There is no commercial system design environment currently available for this application field. At the moment home-grown systems are patched together, which are expensive to develop and maintain. GloNet allows for a suitable extension. Due to the growing number of product variants and increasingly short lifecycles, costs for developing physical prototypes have become increasingly prohibitive, therefore the knowledge of the engineers have to distributed within projects, but limited to one project. GloNet provides role-based and differentiated authentication mechanisms to support this requirement. Furthermore, all requests are tracked. The Infranet partners are realizing embedded software in an area of competitive differentiation and are investigating how to improve and streamline their software processes along the value chain. There are no commercially available systems for keeping the software version synchronized with the mechanical and electrical product data. GloNet allows for a suitable extension.

Due to the increased electronic content and provision of value added services like services associated to the product (solar park) along its life cycle (i.e. service design, decentralised support, proactive maintenance). Managing the supply chain without the basic Virtual Enterprise and tying to deal with as-shipped product structure is a growing challenge. GloNet provides a collaborative solution. Within GloNet we envision a best practice in Virtual Enterprise management for complex industrial units like solar plants that will address these challenges.

The Conceptual Approach

GloNet adopts a cloud-based approach [START_REF] Ommeren | Collaboration in the Cloud[END_REF] for the development of such support environment so that its supporting services can dynamically upgrade without influencing the nodes and stakeholders in the environment. As such the environment stakeholders procure the use of upgraded services, which are always available through the cloud, rather than buying static products which typically need to be installed and maintained by the stakeholders on adequately supporting computing facilities. Specifically, over the cloud two virtual spaces are considered (Fig. 1):

Collaborative solution space -where manufacturers, local suppliers and customers meet to co-design the product (and associated services).

Service provision space -a "registry" of the products, along their life-cycle, where the customer can have access to the specific services associated to the customized product. Organizational structures. Taking into account the possibilities offered by emerging technologies for collaboration support, including adaptive business process and business services modelling, participative environments, and social software, GloNet envisions a dynamic business ecosystem where interconnections between players and their roles are dynamically adjusted to the business opportunities. Therefore the project considers: Inter-play of long-term and short-term networks, i.e. Virtual enterprise Breeding Environments (VBE) and dynamic goal-oriented virtual enterprises (VE) [START_REF] Camarinha-Matos | Collaborative Networks: Reference Modeling[END_REF]. Interplay of manufacturers' network with customers and local suppliers (implementing the glocal enterprise and co-creation notions). Development phase network and PLM support network, in other words, a virtual enterprise might be organized for the product development and dissolve after the product is delivered, while another virtual enterprise, eventually sharing some members with the first one, might be organized to support the product along its life cycle. In order to properly design the organizational structures, GloNet is starting with matching needs (analysis of current practices) with state of the art and emerging organizational models as identified in the disciplines of collaborative networks and organizational ecology and also briefly pointed out in the FInES roadmap [START_REF] Fines | Research Roadmap[END_REF].

Particularly in what concerns the involvement of the customers (and local suppliers) in an open innovation process, GloNet goes beyond the traditional process in which customer inputs are collected at the end of the process. Through the proposed collaboration space, GloNet exploits the synergies created by the involvement of the customer and local suppliers in all phases of the product development and life cycle support. Incremental pool of services, knowledge, and other resources (scalability characteristic). Supporting the notion of extended product -combination of physical product with a set of linked support services (e.g. maintenance, remote diagnosis, remote user assistance, training, ...). A product model will become available in the Service Provision Space as a single entry point for product-related information and services along its life cycle. The product support virtual enterprise will naturally be linked to this product model. The chosen real industry pilot scenario, on the other hand, serves not only the demonstration and validation purposes, but also helps focusing on the requirements elicitation and system design and development.

Cloud Based Platform

GloNet base platform is based on the Cloud Development Stack model CAS OPEN [START_REF] Koelmel | Enable secure access -CAS Open -SaaS Framework[END_REF], which is a standardized objective framework for cloud-offerings. CAS OPEN has a set of broad-based and deep capabilities that enable cost-effective development in the Cloud. The main objective that is addressed by the base GloNet architecture is the provision of a platform that allows for extensive customization and extensibility of SaaS for virtual enterprise functionalities offerings without compromising reliability and security. The architecture is intended not only to guide the software development but also to provide a technology-independent model of the platform. A base framework is assumed, providing the basis for interoperability, incremental service addition, security, and privacy mechanisms.

In order to increase the interoperability and consistency of engineering and manufacturing solutions with efficient collaboration approaches, the GloNet System will be built on top of an open service platform compliant with the OSGi framework.

The system will consist of two major components:

The GloNet-Server, conceived as a central open cloud service infrastructure, consisting of basic functions and components, which are responsible for the business logic, the virtualization of "on premise solutions" as well as for interlinking and aggregating information sources of software services running on the platform. As a consequence of the SaaS customization scenario, development tools consist of two parts: (i) a backend, which is an integral part of the corresponding layer (data, logic, or presentation) and is available not only during the development of a solution, but also during runtime of a GloNet platform instance, (ii) a designer (design-time tool), which is used to create the configuration specifications that are accepted by the corresponding backend. Because a layer's behavior must be adaptable during runtime of a GloNet platform instance, the truly challenging part of the customization mechanism is actually the backend. Since almost all concepts and logic that are needed to support a SaaS customization are part of the backend, the latter will be the focus of the customization tools being developed in the course of the GloNet project.

The ability to use Web services enables the developers of solutions and customizations to leverage already existing (and tested) solutions for particular highly-specialized tasks within their apps, instead of having to reinvent the wheel. For example, an app or app extension for collaborative contact management could invoke an external service to perform a check if a pre-product is available within the value chain. This will be also the approach for integration with legacy systems found within some tenant's organization. An example would be to use a Web service to integrate a tenant's legacy ERP system. Naturally external services are expected to come with a variety of programming interface design conventions (atomic invocations, complex protocol-based conversations, etc), and different implementation technologies (SOAP-based and REST-based). For reasons of completeness and flexibility, the GloNet platform must support the integration of apps with any type of external service. On the other hand, for reasons of facilitating configuration-based integration of external services as an alternative (but not replacement) to programming-based integration, which should still be possible to do, the GloNet platform also needs to set some constraints on service design conventions and implementation technologies. The ubiquity of the cloud helps overcome the previous need to house all the members of the team under one roof. The cloud places communications and coordination within the affordable reach of every SME.

Advanced Functionalities

On top of the cloud-based platform a set of advanced functionalities are designed:

Customized service-enhanced product specification. GloNet addresses ordering complex multi-supplier products which require high degree of customization, and tailoring to varied set of customer's criteria. One of the aims is thus to facilitate detailed specification of such complex customized products, when also enhanced with their required business services, e.g. to support their maintenance, insurance, etc. To achieve this, the development of the following supporting tools and intelligent userbased interfaces is going on:

-Services for customers/local suppliers to iteratively specify product detailsstarting with the semi-open data platform of all sub-product alternatives, the system will facilitate the iterative process of achieving the exact specific final selection of required sub-products, agreed by the customer to be ordered. -Dynamically customizable set of business services enhancing the productbased on the customer profile established dynamically in the previous services, here we focus on the development of a recommendation tree for offering to customer all alternatives of enhancing services around the ordered product. An adaptive dialogue structure is also designed on top of the recommendation tree that uses service reputation for promoting the services to the customer.

Consortia formation and operation support. These functionalities are intended to support the networked multi-stakeholder organizational structures involved in the service-enhanced product development and support. Thus they include the elaboration of models, development of support tools (services) and governance principles regarding: (i) Long-term base networks (manufacturers), (ii) Dynamic goal-oriented virtual enterprises (also involving the customer and local suppliers), (iii) Virtual enterprises for product life cycle support. Furthermore, process monitoring, risk forecasting, and management are also included. Thus the main services here include:

-Services for management of long-term base network -to support the management of long-term alliances of manufacturers, which typically assume the form of a VBE (Virtual organizations breeding environment) with flexible boundaries (different levels of membership). Support services include partners' profiling and competency management, competencies gap analysis, collaboration readiness assessment, value systems alignment assessment, trust management, incentives and assets management. -Services for dynamic consortia formation and order work plana collection of software services for dynamic consortia formation and monitoring involvement of customers and local suppliers. -Services for consortium risk forecasting and management -concerned with identification and characterization of risks in a collaborative context as well as their forecasting, monitoring and launching of preventive / corrective actions. The relationships between risks and competencies and expectations are analyzed. Since emotional / affective aspects play a critical role in the levels of commitment and performance of network members, attention is also devoted to monitoring and promotion of the collaboration "health" at network level.

Conclusions and Further Work

In support of complex service-enhanced products along their life cycle, the approach followed in GloNet aims to: (i) develop a novel way to commonly represent/provide information and knowledge which needs to be shared/exchanged among different stakeholders in the collaborative environment as dynamic software services that may upgrade in time; (ii) generate user-customized interfaces which dynamically adjust to different stakeholders, supporting their access and visualization needs; (iii) provide these services through the cloud, to be available to anybody, at any time, from anywhere, (iv) demonstrate how a broker in very close contact with the customer who gives an order, can iteratively retrieve all needed information to step by step design the customer order and finally presenting the solution that is accepted by the customer, (v) support the negotiation among all involved parties, (vi) generate a workflow from the accepted/negotiated solution, which will then be automatically monitored, while also available for monitoring by the involved stakeholders, during its execution, (vii) the automatic monitoring aims will forecast potential risks, and will suggest prevention measures to the broker during the execution of the order.

A preliminary system and exemplary services have been designed based on the needs identified in the context of solar plants. Next phases involve the field validation of the approach and tools as well as the assessment of their potential applicability to other contexts.

Fig. 1 -

 1 Fig. 1 -Virtual spaces in GloNet Fig. 2 illustrates the key concepts involved in GloNet and main relationships among these concepts.

Fig. 2 -

 2 Fig. 2 -Main supporting concepts

Fig. 3 -

 3 Fig. 3 -GloNet base platform architecture

  Besides the cloud-based platform, the environment includes two main (virtual) spaces: (i) Collaborative solution space -where new products are developed / customized (co-creation/mass customization) through the interplay of the various stakeholders (product development virtual enterprise); (ii) Service provision space -where models of products and associated services are kept along the product life cycle, supported by the product support virtual enterprise.

	Governance models. Under this pillar the following main concepts and support
	functionalities are developed:
	Competencies management and competencies gap analysis (business
	intelligence).
	IPR & business models for co-created products.
	VE creation & negotiation principles, including readiness assessment and value
	systems alignment analysis.
	Performance monitoring and risk assessment, including aspects of "collaboration
	emotional health".
	Customer relationship management ("who owns the customer", brokerage
	services, etc.).
	VE inheritance -transition from product development VE to PLM support VE.

Acknowledgments. This work was funded in part by the European Commission through the GloNet project.


Jeremy W Bryans

John S Fitzgerald

Tom Mccutcheon

Refinement-based Techniques in the Analysis of Information Flow Policies for Dynamic Virtual Organisations

Keywords: Information Flow Policies, Refinement-based Modelling, Event-B, Emergency Response, Verification

Dynamic virtual organisations (VOs) can arise in situations in which it is critical that they continue to operate, even in sub-optimal environments. Models of information flow in dynamic VOs are therefore needed in order to permit the rigorous verification of resilience properties before commitments are made to implementation. This paper proposes a refinement-based modelling approach for the design and analysis of VO policy resilience. The approach is demonstrated by using the refinement-based formalism Event-B to model a VO structure, commonly referred to as the Bronze/Silver/Gold structure that frequently arises in multi-agency response to emergencies. Machine-assisted proof is used to compare the validity of alternative information flow policies in Bronze/Silver/Gold when a fault is induced in the VO structure.

Introduction

Advances in networking technology have made it possible to establish virtual organisations (VOs) of collaborating entities that together enable new capabilities and services that cannot be achieved by the constituent systems alone [START_REF] Camarinha-Matos | Towards an architecture for virtual enterprises[END_REF]. In our work, we are particularly concerned with dynamic VOs whose membership, structure and goals may change during the life cycle [START_REF] Dimitrakos | Towards a Trust and Contract Management Framework for Dynamic Virtual Organisations[END_REF] in response to changing circumstances, and particularly faults or malicious attacks. Dynamic VOs bring significant societal and business opportunities by offering, for example, more agile multi-agency emergency response, or coordinated management of resources such as energy.

In order to take advantage of the opportunities presented by dynamic VOs, it is necessary to address the challenges that stem from their complexity and heterogeneity. These include managing the complexity of the behaviours and interactions between participants, managing access to resources, and communicating effectively between diverse stakeholders. Furthermore, as VOs become established and reliance is placed on them, it becomes vital to have methods and tools that support the validation of properties such as safety or security, and the resilience of the VO in maintaining these properties in the face of failures or malicious attack.

To gain confidence in a VO's resilience, it is paramount to have a precise model of its architecture, the resources, functionality and behaviour of the participant systems, infrastructure, and environment [START_REF] Camarinha-Matos | A comprehensive modeling framework for networked organizations[END_REF]. Models support "trade-off" analysis of alternative designs at early development stages, and the precise determination of the contract (rights and responsibilities) that exists between each participant and the VO. Further, the models themselves can assist communication between the diverse stakeholders.

The goal of our research is to provide models and analysis techniques that can be used to support the comparative analysis of alternative VO models, architectures and policies. We use formal modelling notations in order to take advantage of the analytic techniques underpinning these notations, including proof and model-checking. Rather than attempt to prove the properties of a complex VO in a single attempt, there is a strong case for managing the verification as a series of refinement steps starting with a highly abstract description embodying the desired properties of the VO. From this abstract model, detail can be added step by step, with each incremental refinement being verified.

The contribution of this paper is to demonstrate the viability of a refinement-based approach to the modelling and verification of information flow within VOs and to the analysis of alternative VO policy models with respect to resilience. We describe the relevant state of the art in formal modelling of VOs (Section 2) and introduce our proof-of-concept study based on real major incident response procedures in the London area (Section 3). We present a refinement-based model of this VO in Section 4, focussing on response to serious communications failure. Finally we draw conclusions from the modelling approach and discuss further work (Section 5).

Formal Modelling of Virtual Organisations

Although there is a perception that formal engineering methods are "very hard to apply" [START_REF] Camarinha-Matos | A comprehensive modeling framework for networked organizations[END_REF], improvements in tools and automation are leading to their increased successful deployment on an industrial scale [START_REF] Woodcock | Formal methods: Practice and experience[END_REF]. Their major benefit is in reducing risk in the development of complex systems such as VOs by allowing early detection and elimination of defects and bottlenecks through the analysis of formal, abstract models using static analysis techniques such as proof and model-checking.

Several characteristics of dynamic VOs -operational and managerial independence of participants, heterogeneity and dynamic change -make the formal modelling of VOs a challenge. A truly comprehensive framework would require abstractions to describe functionality, concurrency, distribution and mobility but few, if any, formal methods currently handle all these features successfully.

Although the formal modelling of VOs is in its infancy, useful models of specific aspects of VOs are being constructed. Recent examples include: the use of the modeloriented formalism Z combined with the CSP process calculus to describe identity management problems [START_REF] Haidar | Formal Modelling of a Usable Identity Management Solution for Virtual Organisations[END_REF]; a formal operational model for VO creation [START_REF] Mcginnis | A Formal Framework of Virtual Organisations as Agent Societies[END_REF]; and 'infrastructure-agnostic' formal models of business VOs and Virtual Breeding Environments [START_REF] Bocchi | Structure and Behaviour of Virtual Organisation Breeding Environments[END_REF]. The Vienna Development Method (VDM) has been used to model dimensions of VOs with respect to information flow, including structure, membership, responsibility and provenance [START_REF] Bryans | Formal Modelling of Dynamic Coalitions, with an Application in Chemical Engineering[END_REF], consistent with (sub-)dimensions identified by [START_REF] Camarinha-Matos | A comprehensive modeling framework for networked organizations[END_REF]. However, the VDM models are only analysed by means of simulation [START_REF] Fitzgerald | Animation-based Validation of a Formal Model of Dynamic Virtual Organisations[END_REF], since proof support for VDM is not yet well supported by tools. The Event-B formalism manages the complexity of proof by structuring models as chains of machines linked by refinement relations, and is well supported by proof tools. Further, Event-B has been demonstrated as a viable basis for modelling conflicts of interest within VOs [START_REF] Arenas | Managing Conflicts of Interest in Virtual Organisations[END_REF], as well as QoS parameter negotiation [START_REF] Belhay | Using Event B to specify QoS in ODP Enterprise Language[END_REF].

Most work on formal modelling of VOs has concentrated on the description of normal behaviour, and not faults, accidental or malicious. Error detection and recovery can complicate VOs considerably, increasing the risk of design errors, and we expect that formal models could assist the developer of VO policies to assess the impact of faults and the suitability of resilience mechanisms.

The study in this paper aims to investigate the feasibility of using a refinementbased formal method to analyse the resilience of VO structures in advance of deployment. We use Event-B because of its tool support for proof, and its ability to represent the information flow characteristics of a VO. We model a VO that provides opportunities to explore abnormal behaviour because it exists in a volatile environment that may disrupt its operation. We describe the case study in Section 3 and its refinement-based model, including disruption and recovery, in Section 4.

Bronze-Silver-Gold: The London Major Incident Procedures

Our case study is based on the London Emergency Service Liaison Panel (LESLP) manual [START_REF]Major Incident Procedure Manual[END_REF], which summarises procedures and responsibilities of the emergency services (e.g., police, fire, or ambulance) in response to a major incident. Activities governed by the manual include rescue and transport of casualties, coordination of resources, and handling release of information to the media. Once a major incident is declared, a VO (which we term a coalition) is formed by the services.

The LESLP manual covers many aspects of the coalition life cycle, but we focus on the structural and information flow aspects. These are vital to the successful functioning of the coalition, particularly in managing the release of accurate information, for example regarding the number and location of casualties.

A typical response coalition contains several levels of command: referred to as bronze, silver, and gold (B/S/G). Each service has members working at each level, so we may refer to "Bronze Police" or "Silver Medic". Silver and Gold commands work in inter-agency coordinating groups. Bronze implements tactics defined by silver. Silver formulates tactics to be adopted by each service following strategy determined by Gold. Gold command, geographically distant, contains the service commanders.

Agents at a common level may communicate freely, but between adjacent levels communication is only between agents of the same service. Information flow out of the coalition is subject to several alternative policies. Certain information may be independently released to the media by an individual service, but casualty figures must be cleared by Gold Police. In our case study, we model an alternative information clearing policy in which all members of the Gold co-ordinating group must clear information for release.

Refinement-based Event-B Modelling of Information Flow

An Event-B model [START_REF] Abrial | Modelling in Event-B: System and Software Engineering[END_REF] is a series of machines, each (apart from the first) linked to its predecessor by a refinement relation. A machine contains variables modelling state information, invariants (labelled inv) which constrain the variables, and events which change the state. An event has guards (labelled grd) which must be true for the event to occur, and actions (labelled act) which change the values of state variables. Each machine may have associated carrier sets held in a context visible to the machine.

For each step in the refinement chain, a refinement relation links the variables in the abstract model with those in the concrete model, and is defined by gluing invariants. Adding a machine or a refinement step generates proof obligations to ensure the consistency of the machine and the validity of the refinement. For example, the invariant preservation obligation ensures that invariants hold after an event occurs. An event in the concrete model refines an event in the abstract model if the concrete guards imply the abstract guards, and the variable states reached after the occurrence of the concrete and abstract events are linked by the gluing invariants.

Proof obligations are generated and in some cases proved automatically by the Rodin tools [START_REF] Abrial | An Open Extensible Tool Environment for Event-B[END_REF]. Those that are not proved automatically may be discharged by the developer with the help of the theorem proving interface. Proof obligations may be impossible to prove, in which case the model is inconsistent and should be corrected. Models which are proven consistent are said to be machine-checked.

Section 4.1 outlines a normative model of the B/S/G coalition1 , including a policy governing the flow of information into, through, and out of the coalition. An additional step refines this policy by distributing responsibility for executing it across several coalition agents. Both policies are machine-checked. The model is then extended with an event modelling the loss of a coalition level, and the policies are reexamined with respect to this enhanced model in Section 4.2.

Normative Coalition Model and Information Clearing Policies

The model has four levels of abstraction. The most abstract machine treats the coalition as a single entity. The second machine introduces the B/S/G architecture, and the third machine realises this architecture in terms of individual agents. These model a centralised information clearing policy, in which all Gold members simultaneously clear information for release, for example at a joint meeting. Information is learned, cleared for release, and released in separate, atomic events. In the fourth machine, this policy is refined into a set of actions distributed across members of Gold to give a distributed information clearing policy in which information is ready for release when it has been cleared by all members.

Let INFO be the set of all information. At the initial level, sets of the known, cleared for release and released information are given as global variables. Learning, clearing and releasing of information are represented by events. Here, the Event-B model is shown in abbreviated form. inv2 in Fig. 1 is a key security property of the information flow policy: only cleared information may be released. The B/S/G structure is given by the intermediate machine, part of which is shown in Fig. 2. Bronze, Silver and Gold are defined as members of a carrier set ELEMENT. The coalition variable records the levels currently in the coalition, and coal_known records the information known at each level (inv2). Separate events describe the creation of a coalition at Bronze level and addition of Silver and Gold in ascending order, as envisaged in [START_REF]Major Incident Procedure Manual[END_REF]. Communication takes place only between adjacent levels. For this study, we consider a policy whereby only Gold can clear information for release (ClearInfoGold). The information must be known by Gold (grd1) and not previously cleared (grd2). In ReleaseInfoGold, grd3 ensures that information may be released only after it is cleared. The next level introduces agents. An agent's service (Police, Fire or Ambulance) and level are given by the functions service and element respectively. The relation info gives the information known by individual agents (inv1 in Fig. 3). inv2 and inv3 are the gluing invariants between info and coal_known. They ensure that information known by an agent in info must be known at the level of the agent in coal_known and vice versa. ClearInfoGoldAllElements is the atomic clearing event in this machine. The fourth machine refines the centralised clearing policy into a distributed one (Fig. 4). Any services represented at Gold individually clear information for release (event ClearInfoService), and when all services represented at Gold have cleared information, it can be cleared by the coalition (event ClearInfoGoldDistrib). We also include the consistency invariant (inv1) between the information cleared by the coalition as a whole (variable cleared) and the information cleared by each service (variable serviceCleared). This records the intuition that all information cleared by the coalition must have been cleared by all members of Gold. This requires a change to the event which adds an agent to the coalition: if an agent joins Gold it must agree with the information clearing decisions already made by the coalition.

inv1: info ∈AGENT ↔ INFO inv2: ∀ i,ag • ag ∈dom(service) ∧ i∈ info[{ag}] ⇒ element(ag) a i ∈ coal_known inv3: ∀ lvl,i • lvl∈ dom(coal_known) ∧ lvl a i ∈ coal_known ⇒ (∃ ag • ag∈ dom(element) ∧ element(ag)=lvl ∧ ag a i ∈info) ClearInfoGoldAllElements(i) ≡ grd1: element~[{Gold}] ≠ {} grd2: ∀ a • (a ∈dom(element) ∧ element(a)=Gold) ⇒ i ∈ info[{a}] grd3: i∉ cleared act1: cleared = cleared ∪ {i}
ClearInfoGoldDistrib(i) ≡ grd1: element~[{Gold}] ≠ {} grd2: ∀ a • (a ∈dom(element) ∧ element(a)=Gold) ⇒ i ∈ info[{a}] grd3: ∀ a • (a ∈dom(element) ∧ element(a)=Gold) ⇒ i ∈serviceCleared[{service(a)}]

Analysis of Policy Resilience

A significant risk to the coalition is the loss of a command layer, for example through communications failure. We consider the case where Gold is lost and must be replaced by a new set of agents, and the effect this has on the centralised and distributed information clearing policies. Since it is possible that the level lost was the sole holder of certain information, possible information loss must be included at each abstraction level in the model. In the first machine, this is modelled by the event LoseInfo (Fig. 5). We do not give the event in the intermediate machine. The event which models the loss of an entire level of command in the third machine is RemoveLevelTotal. All obligations resulting from the addition of these events can be proved, although three extra invariants are required in the third machine. However, the distributed clearing policy causes a problem: it is now impossible to prove inv1 in Fig. 4. The offending event is CreateGold. If Gold has been lost and is being recreated, we cannot show that the agent re-forming Gold belongs to a service that is prepared to clear all information that has been cleared by the previous instantiation of Gold.

Investigation of the failed proof, offending event and consistency invariant suggests several ways forward. The policy could be extended to require that an agent re-forming Gold agrees with all previous clearing decisions. This would entail altering the event CreateGold. Alternatively, the consistency requirement between the two policies could require that any released information was once cleared by all services that made up Gold. This would entail maintaining a record of the membership of Gold at all times, and the information cleared by each Gold grouping. A further alternative is to treat the creation of Gold as different from its recreation, and the set of information cleared by the coalition could be reset to empty. The choice between these alternatives would rest with the policy developer and stakeholders. The advantage of the formal model is that the precise cause of the inconsistency is quickly identified and can be communicated to stakeholders, along with the avenues for re-design.

Discussion

This paper has shown how a formal model of a virtual organisation can provide a good basis for an analysis of the information flow policy of the organisation. When potential defects came to light, several options for alternative designs were readily identified.

Many topics are open for further research. Extensions to the model are possible, such as considering the response to multiple intersecting crises. The information model could be refined to include, for example, policies for handling classified information. Modelling the roles and the associated responsibilities of the agents would also lead to richer possibilities for policy analysis, including policies other than information flow. Many emergency response coalitions are much more ad-hoc than B/S/G, and looking at ways to model these less structured ways of dealing with complex crises is also of interest, including ways to integrate formal and semi-formal approaches [START_REF] Camarinha-Matos | A comprehensive modeling framework for networked organizations[END_REF][START_REF] Fitzgerald | The Verifiable Virtual Organisation: a Position Paper[END_REF].

Fig. 2 .

 2 Fig. 2. The architectural-level machine.

Fig. 3 .

 3 Fig. 3. The agent-level machine.

Fig. 4 .

 4 Fig. 4. The distributed clearing policy.

Fig. 5 .

 5 Fig. 5. Removing a level of command.

The models used in this paper are available at http://deploy-eprints.ecs.soton.ac.uk/

Acknowledgements

The authors' work is supported by the EU FP7 Integrated Project DEPLOY (www.deploy-project.eu) and the EPSRC Platform Grant TrAmS.


María-José Verdecho
email: mverdecho@cigip.upv.es

Raúl Rodríguez-Rodríguez

Juan-José Alfaro-Saiz

A Structured Methodology to Implement Performance Measurement Systems in Collaborative Networks

Keywords: performance measurement systems, collaborative networks, performance management

Collaboration is one of the most commonly used strategies in the business environment. Enterprises that collaborate need reliable and efficient performance information. However, many collaborative enterprises fail to implement a common performance measurement system in an adequate manner due to the lack of sound mechanisms that connect all the elements within a performance measurement system. The purpose of this paper is to provide a methodology based on a multi-criteria decision method that aids to implement the different elements that compose a performance measurement system for collaborative networks. With this methodology enterprises have a tool to define all the aspects involved in the performance measurement system and to implement it. This approach has been applied to a collaborative enterprise network belonging to the automotive sector.

Introduction

Collaboration is one of the business models that enterprises adopt to remain competitive. Companies collaborating share the responsibility of exchanging common planning, management, execution, and performance measurement information [START_REF] Anthony | Supply chain collaboration: success in the new internet economy[END_REF]. In addition, collaboration requires the commitment of human, financial or technical resources to build and sustain a more competitive business model [START_REF] Bowersox | How to master cross-enterprise collaboration[END_REF]. For that reason, it is necessary to manage the evolution of the collaborative relationship by defining performance measurement systems (PMS) that aid to collect the necessary information in order to manage the activities of the collaborative association. In the literature, there has been an increasing interest in the development of PMS for interorganizational contexts [START_REF] Brewer | Using the Balanced ScoreCard to measure supply chain performance[END_REF][START_REF] Bititci | Measuring and managing performance in extended enterprises[END_REF][START_REF] Folan | Development of an Extended Enterprise Performance Measurement System[END_REF][START_REF] Alfaro | Performance measurement system for Enterprise Networks[END_REF] and recently some PMS were developed for specific collaborative contexts [START_REF] Romero | A conceptual Model for Virtual Breeding Environments Value System. Establishing the Foundation of Collaborative Networks[END_REF][START_REF] Msanjila | Trust analysis and assessment in virtual organization breeding environments[END_REF][START_REF] Westphal | Measuring collaboration performance in virtual organizations[END_REF]. This is because, as collaborative relationships present specific characteristics that need to be managed such as trust, commitment, cooperation, etc. [START_REF] Verdecho | Foundations for collaborative performance measurement[END_REF][START_REF] Verdecho | COL-PMS: a collaborative performance measurement system[END_REF]. Then, PMS developed for inter-organizational contexts should present specific characteristics to be useful for these contexts. One of this characteristic is related to the need that the design and implementation phases of PMS are coordinated in order to build them adequately. In this sense, decision makers usually deal with other important issues such as the prioritization of performance objectives in order to know which the most strategic objectives are and, therefore, in which aspects enterprises should be focused and allocate resources. Despite the importance of these activities, the inter-organizational PMS developed in the literature present some limitations for providing weights [START_REF] Yüksel | Using the fuzzy analytic network process (ANP) for Balanced Scorecard (BSC): A case study for a manufacturing firm[END_REF]. Then, PMS should incorporate methods for solving these issues in order to get an adequate PMS design and implementation.

In order to prioritize objectives, it is useful to define weights for the different objectives which can be stated as a multi-criteria problem involving different actors. In the same vein, structuring and consolidating data may also be solved as a multicriteria problem. Therefore, multi-criteria methods can contribute to the elaboration and establishment of the performance measurement systems. The main goal of this paper is to propose a novel methodology to design and implement PMS in collaborative networks by using a multi-criteria decision-making approach. With this methodology, enterprises will have a tool that describes the steps to be followed by all the collaborating enterprises in order to define, reach agreement and manage the evolution of the collaborative enterprise network. Then, this methodology is developed to manage the performance of the association of enterprises instead of the individual enterprises. Evolution is managed by analyzing the performance reached by the whole association at the different periods and deriving, defining and implementing actions plans when performance is not achieved.

The structure of this paper is as follows. First, a literature review of interorganizational PMS and multi-criteria decision analysis methods are presented focusing attention on the Analytic Hierarchy Process (AHP) method. Then, the methodology proposed to implement performance measurement systems is presented. Next, a case study of a collaborative enterprise network belonging to the automotive sector is described. Finally, conclusions are exposed.

Literature Review

Collaborative enterprise networks involve that different partners are working together for mutual benefits. Therefore, the definition of PMS for managing its activity is a task that has to be made by all the collaborative partners. There are several PMS developed in the literature for inter-organizational contexts such as the works [START_REF] Brewer | Using the Balanced ScoreCard to measure supply chain performance[END_REF][START_REF] Bititci | Measuring and managing performance in extended enterprises[END_REF][START_REF] Folan | Development of an Extended Enterprise Performance Measurement System[END_REF][START_REF] Alfaro | Performance measurement system for Enterprise Networks[END_REF][START_REF] Romero | A conceptual Model for Virtual Breeding Environments Value System. Establishing the Foundation of Collaborative Networks[END_REF][START_REF] Msanjila | Trust analysis and assessment in virtual organization breeding environments[END_REF][START_REF] Westphal | Measuring collaboration performance in virtual organizations[END_REF]. These PMS are useful structures for defining and structuring performance measurement information from the strategic level to the process level by deploying linkages among the performance elements. However, they lack of mechanisms to prioritize the performance measurement elements data so that performance can be analyzed under an assessment making preference to those aspects that are more relevant for the sustainability of the collaborative enterprise network.

On the other side, there are many multi-criteria methods. In fact, multi-criteria methods are classified into two groups [START_REF] Barba-Romero | Decisiones Multicriterio: fundamentos teóricos y utilización práctica[END_REF]: Multiple Objective Decision Methods (MODM) and Multiple Attribute Decision Methods (MADM). The main difference between both methods is that in MODM, decision makers need to reach multiple objectives that are in conflict of interest and the number of alternatives is elevated. However, MADM problems focus on obtaining a preference ranking on the alternatives characterized by multiple attributes that are in conflict and the number of alternatives is limited. In our problem, the number of performance objectives is limited and discrete so that MADM techniques are to be used. There are several MADM methods such as Multiple Attribute Utility Theory, (MAUT) [START_REF] Fishburn | Independence in utility theory with whole product sets[END_REF], ELECTRE (ELimination Et Choix Traduisant la REalité) [START_REF] Roy | Classement et choix en présence de points de vue multiples: la méthode ELECTRE[END_REF], PROMETHEE (Preference Ranking Organization METhod for Enrichment Evaluations) [START_REF] Brans | How to select and how to rank projects: the PROMETHEE method[END_REF] and the Analytic Hierarchy Process, AHP [START_REF] Saaty | The Analytic Hierarchy Process[END_REF].

AHP aims at integrating different measures into a single assessment for ranking decision alternatives which is the case of our problem. Also, ranking of objectives involves both tangible and intangible aspects and AHP deals with both types of aspects. This is because overall assessment should not only consider quantitative performance data but also some other criteria that are critical for successful parnerships and are not directly quantifiable, e.g. trust and commitment [START_REF] Mohr | Characteristics of partnership success: Partnership attributes, communication[END_REF]. In addition, AHP has been used for many applications involving performance measurement criteria such as selecting a supplier [START_REF] Verdecho | A multi-criteria approach to select suppliers based on performance[END_REF][START_REF] Masella | A contigent approach to the design of vendor selection systems for different types of co-operative customer/ supplier relationships[END_REF][START_REF] Ghodsypour | A decision support system for supplier selection using an integrated analytic hierarchy process and linear programming[END_REF], selecting performance indicators for supply chain management [START_REF] Bhagwat | Performance measurement of supply chain management using the analytical hierarchy process[END_REF], evaluating performance of IT department in the manufacturing industry in Taiwan [START_REF] Lee | A fuzzy AHP and BSC approach for evaluating performance of IT department in the manufacturing industry in Taiwan[END_REF], and selecting ERP systems in textile industry [START_REF] Cebeci | Fuzzy AHP-based decision support system for selecting ERP systems in textile industry by using balanced scorecard[END_REF]. However, there is not an application of AHP for supporting PMS design and implementation within inter-organizational contexts. For this reason, the purpose of the remaining of this paper is to present a methodology that uses AHP method to support the prioritization of the objectives within a PMS and the composition of an assessment for the whole collaborative network that fills this research gap.

The Proposed Methodology to Support the Implementation of PMS in Collaborative Contexts

In [START_REF] Verdecho | A multi-criteria approach to select suppliers based on performance[END_REF], the COL-PMS framework for managing performance within collaborative contexts is presented. The COL-PMS framework integrates the social side of collaboration within an integrated and solid PMS structure. The main purpose of this PMS is to support the decision-making process of the enterprises and entities that collaborate. For that reason, it is necessary that the PMS considers two levels: interorganizational level (where collaboration takes place) and individual enterprise level. Fig. 1 shows the phases of the methodology proposed to implement the COL-PMS framework by using AHP which is composed of seven phases. In the phase 1, the performance elements of the PMS are defined. In this work, the PMS structure used is the COL-PMS but other PMS structures may be used. Then, the AHP method is applied to build a model (phase 2). The AHP method structures the decision problem in a hierarchy of levels. These levels are linked by unidirectional dependence relationships. In the upper level of the hierarchy, it is defined the ultimate goal of the decision problem. Then, the criteria that contribute to achieve the goal stand in the second level. In the next levels, intermediate sub-criteria and attributes that compose the hierarchical structure are located. Finally, in the last level, the decision alternatives are established. Using levels allows decision makers to focus on a small set of decisions [START_REF] Saaty | The Analytic Hierarchy Process[END_REF]. The AHP method provides relative weights to each element within a level depending on its contribution to an element linked to it that is located on the immediate upper level. In our case, as we use the AHP model to obtain the weights of the performance objectives, we will have three levels (see Fig. 2): PMS vision (main goal), perspectives (criteria) and, finally, performance objectives (alternatives). Once the model is built, it is needed to make pairwise comparisons in each level using the fundamental scale of Saaty [START_REF] Saaty | The Analytic Hierarchy Process[END_REF], in order to obtain the pairwise comparison matrices (phase 3). After pairwise comparisons matrices are completed, the local priorities of the compared elements (priority vector) are calculated and consistency of judgements checked following the procedure described in [START_REF] Saaty | The Analytic Hierarchy Process[END_REF]. Once all priority vectors are obtained and consistency verified, the final weights for the alternatives are calculated (phase 4). For that purpose, priorities of decision alternatives are combined together with the sets of priorities of the criteria. Then, in phase 5, it is performed a sensitive analysis to check how changes in the local weights of one of the criteria or alternatives affect the final priorities previously obtained. The purpose of this phase is to verify that the solution obtained as the preferred alternative is robust enough. In case that the solution is not robust, it is needed to go back into the phase 3 to analyze the pairwise comparison matrices defined. In phase 6, the data regarding the performance indicators is collected. Finally, phase 7, it is obtained the overall performance evaluation by multiplying the priority of every performance objective (given by the normalized priority) and the value reached in its corresponding performance indicator.

Case Study

The methodology has been applied to a collaborative enterprise network belonging to the automotive industry in Spain which is composed raw material suppliers, design centres and manufacturing plants (of a plastic injection-moulding leading group) working for main OEMs. Due to the success of a new product launched, and the new market needs regarding this new product, the corporation pursued to change the policy and orientation towards collaborative working in order to agree the terms, commitment, money investments and resource and information sharing. One of the components of this product is critical as the technology and know-how required to design it and manufacture it is not a core capability of the manufacturer therefore collaborative working seem reasonable.

The first phase of the methodology consists of the definition of the PMS elements. Managing directors of the different enterprises assessed were in charge of the decision making of the different phases of the methodology. It took several meetings to reach an agreement on the strategic aspects of the relationship as the enterprises come with different backgrounds and understand in a different way the main components for the business vision. Once the global performance elements were defined, the different enterprises performed some adjustments into their performance indicators at the local level to accommodate all the relevant performance information coherently. Table 1 shows the performance elements (objectives and KPIs) defined for the collaborative enterprise network level. It consists of fourteen objectives and KPIs (divided into the five performance perspectives) which seems a reasonable number. These KPIs have been defined by the enterprises based on the objectives that they want to reach. It took two meetings to define these KPIs.

In the phase 3, in order to fill in the pairwise comparison matrices it was necessary to establish an initial meeting for explaining the AHP method. As this phase involves decision makers of all the enterprises, several possibilities can be used to obtain a final solution such as voting, aggregation methods on individual preferences or reaching consensus [START_REF] Saaty | The Analytic Hierarchy Process[END_REF]. The companies agreed to use the aggregation on individual preferences if the initial judgement was equal or similar for all of them. However, if there was a large difference of judgement, this point needed to be dealt with in meetings for reaching consensus or a closer point of view. In order to reach consensus, the managing directors discuss the preferences until a better understanding is achieved. Therefore, a combined solution was applied in order to get an approximate common view of the problem. Then, enterprises meet several times in order to fill in the pairwise comparison matrices. In other cases, if consensus is not reached, other methods can be used such as voting. In the phase 4, the weights of the objectives are obtained. Results showed that the most important objectives representing more than 70% of the total weight were: FO1 Increase sales (with normalized weight of 0,16), CPO1 Increase market share (0,12), FO2 Increase high quality product margins (0,11), CPO3 Increase customer satisfaction (0.09), PO4 Decrease non-conforming parts (0,09), LGO1 Increase innovation capability (0.08) and CO3 Maintain equity (0,08). It can be observed that the relevant objectives belong to all the performance perspectives but the importance of the perspectives differ, being the financial perspective the most relevant followed by the customer perspective. It is to be noted that the objective CO3 Maintain equity reaches a weight of 0,08. This fact notes the importance of social climate aspects for sustaining collaboration in the long time.

In the last phase it is obtained the final results. The analysis showed that performance was mainly achieved by some of the most relevant objectives (those objectives with highest weight). However, financial objectives were not accomplished in the desired level (accomplished around 20%) and decision makers have to reassess what is expected in market conditions. Another objective that is not achieved is the decreasing of non-conforming parts (accomplished around 50%). For those objectives that have not reached the expected results, actions plans are to be developed which allows reassessing the current targets or reaching them properly. It has to be noted that performance achievement was only reached at the 60% what was under the initial expectations (70%). However, results showed that performance measurement implementation has provided performance knowledge to the collaborative network as well as a tool for monitoring performance from now on.

From an information systems point of view, it has to be said that a web-based tool is being built in order to make possible to implement the system. Some of the next steps involve completing the tool and testing it, training further the people that are going to use it, move the data into the application and feed the system with updated data in order to analyze how the performance of the collaborative enterprise network evolves.

Conclusions

The literature counts with inter-organizational PMS that are useful structures for defining performance measurement systems. However, they lack of mechanism to prioritize the performance measurement elements data. This paper introduces a structured methodology supported by a multi-criteria method to aids to implement PMS for collaborative networks aiming to fill this research gap. Adaptations of this methodology can be made to manage other inter-enterprise relationships such as supply chains, etc. Further research work will involve the full development of the web tool in order to not only provide the storage of data and calculation of the results but also deals with the report analysis settings. In addition, it is needed to further testing the web tool and observe its evolution as well as the evolution of the PMS and the performance of the collaborative enterprise network in the long time. Other interesting research line is the validation of the proposed methodology in other contexts as well as the adaptation of other PMS and MADM techniques.

Fig. 1 .Fig. 2 .

 12 Fig. 1. Methodology for implementing a PMS by using AHP

PO4

  Decrease non-conforming parts = production lead time variation (monthly) KPI7 = new product development lead time variation (per project) KPI8 = number of performance improvement initiatives implemented (semester) KPI9 = number of non-conformance parts send to customer (weekly) of agreements failed (monthly) KPI13 = number of times that information is sent delayed (monthly) KPI14 = meetings to discuss perception of equity after agreement (quarterly)

Table 1 .

 1 Performance elements of the collaborative enterprise network.

	Perspect.	Objectives	KPIs
	Financial	FO1 Increase sales	KPI1 = sales (monthly)
		FO2 Increase high quality product	KPI2 = average of high quality products
		margins	margin variation (monthly)
	Customer CPO1 Increase market share	KPI3 market share variation
			(quarterly)
		CPO2 Increase customer loyalty	KPI4 = number of old customer
			purchases/ total purchases (quarterly)
		CPO3 Increase customer satisfaction	KPI5 = number of claims/complaints
			(weekly)
	Process	PO1 Decrease production lead time
		PO2 Decrease new product
		development lead time
		PO3 Implement initiatives for
		production performance improvement

Acknowledgments. This work has been developed within the framework of a research project funded by the Polytechnic University of Valencia, titled "Design and Implementation of Performance Measurement Systems within Collaborative Contexts for aiding the Decision-making Process", reference PAID-06-08-3206.