Iris Karvonen
email: iris.karvonen@vtt.fi

Kim Jansson
email: kim.jansson@vtt.fi

Mikko Uoti
email: mikko.uoti@vtt.fi

Promoting Remanufacturing through Collaboration

Keywords: remanufacturing, life cycle, collaboration

Remanufacturing is an ultimate form of recycling by manufacturing "good as new" products from used products. Through remanufacturing, materials and energy can be saved and less waste is produced. However, at present, the application of remanufacturing is common only in specific industrial fields and geographic areas. This paper describes challenges identified and discusses how collaboration and networking of companies can support the implementation of remanufacturing. In addition to cases described in literature, the study uses information collected from Finnish case companies operating in remanufacturing.

Introduction

Remanufacturing is one form of product end-of-life strategies, often called 6R: reduce, reuse, recycle, recover, redesign, remanufacture [START_REF] Biller | Innovation in Global Manufacturing: Sustainability for Business Success[END_REF], aiming for resource efficiency. Remanufacturing can be seen as an ultimate form of recycling: it re-uses more of the assets put in a product or a component than recycling: in recycling large amounts of energy and labor are lost [START_REF] Macarthur | Towards a circular economy. Economic and business rationale for an accelerated transition[END_REF]. The idea is not to refit the product or product part for the same user but systematically take back end-of-life goods and re-use them or their components for new users.

There are several definitions for remanufacturing, for example: "recycling by manufacturing "good as new" products from used products" [START_REF] Steinhilper | Remanufacturing -The Ultimate Form of Recycling[END_REF], "the process of restoring a non-functional, discarded, or traded-in product to likenew condition" [START_REF] Lund | Remanufacturing -An American perspective[END_REF].

Remanufacturing is one form of so called "circular economy", defined as "an industrial system that is restorative or regenerative by intention and design" [START_REF] Macarthur | Towards a circular economy. Economic and business rationale for an accelerated transition[END_REF]. Circular economy is not based on consumption but on restorative use. A recent report [START_REF] Macarthur | Towards a circular economy. Economic and business rationale for an accelerated transition[END_REF] reviews the potential of circular economy from a European viewpoint and estimates enormous potential for savings at the European level and new innovation potential to realize the circular economy. Thus it can be seen as one path to reindustrialization in Europe.

Remanufacturing has been performed in some form for decades but as an industrial activity it is well known mainly in specific industrial fields and few geographical areas, like photocopier, printer and camera industry in Japan [START_REF] Matsumoto | An analysis of remanufacturing practices in Japan[END_REF], motor vehicle parts, electrical components, industrial machinery and office furniture industry in USA [START_REF] Lund | Remanufacturing -An American perspective[END_REF] and car industry in Germany [START_REF] Steinhilper | Remanufacturing -The Ultimate Form of Recycling[END_REF]. Currently, as the awareness and interest in ecologic sustainability is growing, also remanufacturing is achieving more attention. In Europe interest for remanufacturing is highly linked to the European requirements of recycling in car industry. In China remanufacturing is still in the primary stage but there is political pressure to grow in this area [START_REF] Bücker | A SME View to the remanufacturing Business-trends, Challenges & Critical Impacts[END_REF].

To move from small-scale remanufacturing to industrial remanufacturing, radical rethinking of physical products, their lifecycle and the production and service system as well as the creation of totally new operations and value networks is needed. Chapter 2 presents the background of this paper. Chapters 3-4 describe the benefits and challenges of remanufacturing, both based in literature and commented with the Finnish case company experience. Chapter 5 describes the remanufacturing processes and how collaboration and networking between enterprises could support overcoming some barriers. Chapter 6 gives the conclusions.

Research Context and Approach

In Finland a research programme "Green Growth" was started by the national research funding organization Tekes in 2011. The aim of the programme is "to identify potential new growth areas for the sustainable economy business, which are essentially based on lower energy consumption and sustainable use of natural resources" [START_REF][END_REF]. Within this programme, in 2012, project DemaNET was started. DemaNET comes from "Dematerialization and Sustainable Competitiveness through New Models for Industrial Networking". One of the focus areas of the project is remanufacturing. The aim is to study how remanufacturing can best be applied in Finnish industry. The project is participated by ten industrial companies which have interest for sustainability and part of them specifically in the remanufacturing business. The companies are on different application levels. Four of them have currently some commercial remanufacturing activities; one of them just started a new remanufacturing factory for specific product components. In future the companies may also act in different roles: One of them is looking for partners to develop the activity in a specific region; as an SME it is not able to perform remanufacturing alone. One of the companies is a potential service provider for remanufacturing but has no activities and experience yet in this field.

This paper is based on the work carried out in DemaNET during the first year. Previous research about remanufacturing has been studied to identify its benefits, challenges and applications and to analyze the processes and systems applied. The industrial views have been surveyed through semi-structured interviews and workshops with the case companies. The observations from outside Finland and the experience of the companies have been shared and discussed between the participants. Finally in the project the aim is to consider how the remanufacturing concept could be applied in Finnish industry; how the barriers could be overcome and what kind of actions are needed in the long term to promote remanufacturing on a larger scale in industry and economy.

Remanufacturing Benefits

Within the IMS (Intelligent Manufacturing Systems) a vision and roadmap for sustainable manufacturing has been developed in 2010 [START_REF] Ims | Roadmap on Sustainable Manufacturing[END_REF]. The vision foresees that "Successful European enterprises have to adapt to sustainable manufacturing approaches, based on a precise esteem of the whole life-cycle environmental impact." Thus sustainability is seen as a competitive factor for future industries and reindustrialization. The roadmap [START_REF] Ims | Roadmap on Sustainable Manufacturing[END_REF] also recognizes remanufacturing: "The development is going towards an "eternal life-cycle" of products and remanufacturing is becoming more important as many countries are tightening environmental regulations or legislations in economic activities".

Remanufacturing is referred to as a "win-win-win" situation: customers need to pay less for the remanufactured products or components, remanufacturing companies earn more and the environment benefits [START_REF] Lundmark | Industrial Challenges within the Remanufacturing System[END_REF]. As a whole, remanufacturing is expected to contribute to all three dimensions of sustainability (environment, economy, society): Remanufacturing "saves material and energy resources, prevents waste, creates skilled jobs and produces substantial savings over new goods with new components". While looking at remanufacturing from the American perspective also Lund & Hauser [START_REF] Lund | Remanufacturing -An American perspective[END_REF] identify several benefits at the level of society: It makes products more broadly available at lower prices, it makes a contribution to conservation of materials and energy and it provides employment income and acquisition of skills and expertise which can lead to additional business opportunities for repair, remanufacture, or manufacture, thus providing local employment and training. Thus through becoming more common remanufacturing can support the reindustrialization.

The case companies involved in DemaNET project also recognized the importance of all the three sustainability dimensions as benefits of remanufacturing. Even if sustainability is often used as a selling argument, the companies regarded that so far only part of their customers are highly interested in sustainability. The main driver of the case companies for remanufacturing is profitable business. Through remanufacturing new markets and customer groups may be reached. As two of the companies apply remanufacturing for spare parts of heavy machines they see remanufacturing also as a method to keep up the spare part market for themselves. Sometimes there is a concern if remanufactured products decrease the sales of new ones. This was not seen relevant in the case companies. On the contrary they saw that remanufacturing may support sales of new products through taking back the used ones; this is seen as a part of the "whole service" to the customers. Remanufacturing also supports the feedback of product experience: information flow from product use to new product design.

Barriers and challenges

Even if remanufacturing is widely spread in some limited fields or geographical areas, in other fields it is small scale activity. Partly this is because the raw materials or components are currently not expensive enough, the awareness of remanufacturing is still low and the regulations do not oblige for ultimate recycling. On the other hand, there are also barriers to implement remanufacturing as a profitable business. Matsumoto & Umeda [START_REF] Matsumoto | An analysis of remanufacturing practices in Japan[END_REF] and Lundmark et al. [START_REF] Lundmark | Industrial Challenges within the Remanufacturing System[END_REF] have identified three main areas of challenges according to the main phases of remanufacturing:

(1) Challenges related to the collection of used products / availability of cores: To establish remanufacturing sufficient volume of cores (used products or components to be remanufactured) need to be available and brought together for remanufacturing. Even if there is potential for sufficient core volume in the market area, the remanufacturing companies need to take care that the cores are returned to them.

(2) Challenges related to remanufacturing processes (remanufacturing phase): Not all products or product parts can be remanufactured in a reasonable way. There may be technical challenges, it might be difficult to assure of the required quality, or the costs and lead time are too high. It is often difficult to identify the potential products for which remanufacturing is profitable, technically feasible and really sustainable [START_REF] Östlin | On Remanufacturing Systems -Analysing and Managing Material Flows and Remanufacturing Processes[END_REF].

(3) Challenges related to the demand for remanufactured products [START_REF] Matsumoto | An analysis of remanufacturing practices in Japan[END_REF] and redistribution [START_REF] Lundmark | Industrial Challenges within the Remanufacturing System[END_REF]. One main challenge of demand is to reach the customers' acceptance and trust in remanufactured products.

A challenge related to all these phases is the difficulty of balancing the supply and demand [START_REF] Matsumoto | An analysis of remanufacturing practices in Japan[END_REF][START_REF] Lundmark | Industrial Challenges within the Remanufacturing System[END_REF][START_REF] Östlin | On Remanufacturing Systems -Analysing and Managing Material Flows and Remanufacturing Processes[END_REF][START_REF] Bennekrouf | A Generic Model for network design including remanufacturing activities[END_REF]. Remanufacturing companies most often do not have control about the quantity, quality and timing of the returned products.

Additionally, other types of challenges can be identified, related to management and business (for example cost-effectiveness and pricing), legislation and IPR issues.

The challenges identified by the project case companies were mainly in line with the observations in literature. One of the main criteria to start and run profitable remanufacturing is to reach sufficient volume. For part of the companies this could be managed through the selection of proper components or modules for remanufacturing the volume of which is high enough. Because of insufficient volume one of the companies is currently able to perform remanufacturing only in the primary market area. In one SME case, the manufacturer of large and heavy products, the product volume is distributed globally and no region has sufficient volume for remanufacturing. In addition to the mentioned challenges, the companies highlighted the need for local market understanding and knowing the local government regulations (for example sometimes the export of cores may be prohibited). When developing new activities in remanufacturing, the companies also experienced a need for resources and knowledge: technical information and test specifications are needed. Additionally the products should be better designed for reuse and remanufacturing.

Remanufacturing Processes & Collaboration

External and Internal Processes

Remanufacturing processes can be seen as consisting of external and internal processes, figure 1. The external process has two parts: "external in" taking care of the collection and input of cores and "external out" distributing the output of remanufactured products to customers. The figure presents different routes for the external processes; they are not present simultaneously for one product. The remanufacturing internal processes contain the needed manufacturing steps to recondition the incoming cores to the needed quality level. Not all used products qualify for remanufacturing; the pre-check of the cores may be performed in different phases, depending on the case. Storage and transport operations are needed both inside the phases and between them. In figure 1 storage and transport are left out, to keep the description more simple. To perform remanufacturing it is necessary to build up the whole remanufacturing system, not only the actual remanufacturing activities.

External in process (collection of cores)

The external in process takes care of the collection of the used products or components (cores) from the customers. As seen in figure 1 there are several options for the core return. Delivery of spare parts or receiving used products when buying new ones, are typical occasions for core collection. Other sources of cores are for example salvage operators and core brokers, rental units returned at the end of lease, and items found defective during an initial warranty period [START_REF] Lund | Remanufacturing -An American perspective[END_REF]. As mentioned above in chapter 3, the market needs to be high enough to create the collection channels and the reverse logistics system.

The collection of cores needs to be organized easy for the customer and costefficient for the remanufacturer. To support the core availability the remanufacturing companies often create incentives for returning them. They offer cash or deposits of used products or discounts when purchasing new products and returning the used ones. Offering products as a service, leasing or collaboration with leasing companies can support managing the used products or parts and thus may help both to reach sufficient volume and to decrease the supply uncertainty.

Internal remanufacturing processes

The remanufacturing internal processes include the steps for the recondition of the incoming cores to the needed quality level: inspection, cleaning, disassembly, reprocessing, reassembly, testing and storage [START_REF] Steinhilper | Remanufacturing -The Ultimate Form of Recycling[END_REF][START_REF] Sundin | Product and Process Design for Successful Remanufacturing[END_REF]. Depending on the core, these phases may be performed in a different order. Not all products are suitable for remanufacturing. Hauser & Lund [START_REF] Hauser | Remanufacturing -An American Resource[END_REF] identify the following remanufacturing criteria from the product viewpoint: Technology exists to restore the product, product is made up with standard restorable parts, cost of core is low relative to savings in product cost achieved through core reuse and the product technology is stable over more than one lifecycle.

The most cost-efficient and sustainable solution can be achieved if the product is specifically designed for remanufacturing. This means that the products are easy to disassemble and assemble, more durable material is selected, the parts are easy to recover and test and standardized as far as possible. Currently, only few products have been designed for remanufacturing and few designers are aware of design for remanufacturing [START_REF] Hatcher | Design for Remanufacture: a Literature Review and Future Research Needs[END_REF].

External out process (remanufactured products to customers)

There are also several options for the sales and distribution of remanufactured products and components to the market but not all of them are applied simultaneously for one product. Sometimes they are sold through the same channels as new ones (spare parts) but often the market areas or the customers for used and remanufactured products are different from those of new products. In some fields with high volume specific remanufacturing marketplaces are available in the internet. The customer base can be enlarged by identifying proper cores for the remanufacturing (for example spare parts), a credible quality offer (for example longer guarantee than for new parts), lower pricing and financial incentives for the used cores when buying remanufactured products.

One way to stabilize the demand of remanufactured parts is to use them as components in new products. According to Matsumoto & Umeda [START_REF] Matsumoto | An analysis of remanufacturing practices in Japan[END_REF], in Japan remanufactured components are used also in new products in photocopier and camera industry. The advantage is that the timing of supply does not depend on the timing of returns, the customer does not define the reuse ratio and the potential conflict between sales of new and remanufactured products is avoided.

Actors and Roles in Remanufacturing

In previous research, three main categories of remanufacturing are identified [START_REF] Lund | Remanufacturing: The Experience of the United States and Implications for Developing Countries[END_REF][START_REF] Parker | An Introduction to remanufacturing[END_REF][START_REF] Sundin | Remanufacturing of Products used in Product Service System Offerings[END_REF], according to which partner takes care of remanufacturing:

1) the OEM (Original Equipment Manufacturer) itself, 2) contracted remanufacturers; "official" contractors / agents, and 3) independent or 3 rd party operators. This classification mainly focuses on the internal remanufacturing process -taking into account the external processes brings out additional roles and actors. There are important tasks to be performed also in the external processes, in the collection of cores and the distribution of remanufactured products. These tasks offer potential for additional roles and services as the company performing the real remanufacturing is not always able or the best option to take care of the logistics.

The involved case companies already active in remanufacturing all followed mainly the OEM approach: they had the control of the whole remanufacturing process even if they could use the original suppliers of the components also for the remanufacturing. The other ones interested in remanufacturing could as well select the contracted remanufacturing option or operate themselves as 3 rd party actors in the remanufacturing process.

Enterprise Networking in Remanufacturing

To succeed in remanufacturing business, the companies need to achieve sufficient volume and cost-efficiency, flexibility and quality. These requirements are often drivers for inter-enterprise collaboration in industry [START_REF] Kürümlüoglu | Base concepts[END_REF]. Could collaborative networks -approach and the developments in the field [START_REF]Methods and Tools for Collaborative Networked Organizations[END_REF][START_REF] Romero | Green Virtual Enterprise Breeding Environments: A Sustainable Industrial Development Model for a Circular Economy[END_REF] support also companies as they are striving to set up remanufacturing?

In collaboration networks -research [START_REF] Kürümlüoglu | Base concepts[END_REF][START_REF]Methods and Tools for Collaborative Networked Organizations[END_REF] two main enterprise networking concepts are distinguished, based on the objective and the duration of the collaboration. The Collaboration network or Breeding environment -concept refers to long-term co-operation and creation of preparedness between the enterprises while virtual organisations or Virtual enterprises (VE) are temporal and focused on achieving a specific task. After fulfilling the task a VE is dissolved. Using these concepts in the remanufacturing context the collaboration network creates the preparedness for collaborative remanufacturing while the remanufacturing itself could be performed by a Virtual remanufacturing enterprise. When talking about what happens inside the factory walls as well a term "virtual factory" could be used. From the outside world the Virtual Remanufacturing Enterprise behaves and acts as a single company, but internally it consists of several partner organisations. Examples of companies that together could perform the process are cleaning, reprocessing, painting, coting, testing and logistics companies. The participation partner can be replaced over time. The Virtual Remanufacturing Enterprise could be created from the remanufacturing network for a specific product or component. Depending on the product type its duration could extend over the product generation lifetime or be even focused on one large product with low market share and volume.

Collaboration between different actors may be needed both in internal and external processes. Through the analysis of the project cases and their potential forms in the future three different network types were tentatively identified:

-OEM centric remanufacturing network: managed by the OEM but may include contracted remanufacturers, -Industry-specific remanufacturing network: managed by a contracted remanufacturer or an independent actor, -Location-based remanufacturing network / "Remanufacturing park": mainly independent actors but may also have contracts with OEMs. In future, also remanufacturing ecosystems could emerge, extending over the different types and allowing collaboration and enriching across different industrial fields.

As mentioned above, the case companies already active in remanufacturing follow the OEM approach in remanufacturing. Analysis of their processes, however, shows, that the one having most wide remanufacturing activities is not performing the whole remanufacturing process alone, but has collaboration partners both in the internal and the external processes. Here the partners in the remanufacturing network are a subpart of the network of new product manufacturing: most of them also participate in the logistics, manufacturing or maintenance activities of new products. Only few specific centres for remanufacturing have been created. This kind of remanufacturing network could be called "OEM-centric remanufacturing network": it is managed and controlled by the OEM. In this way the OEM can take care of its brand, keep the customer relationship and ensure the quality of the remanufactured products or components.

The two other case companies already active do not have a corresponding network created but they also do not have as high volumes. However, while increasing the volume they could also benefit about creating collaboration in external or / and internal processes.

One of the case companies experienced difficulties to set up remanufacturing activities outside its main market area, because of too low market share and volume. In this case manufacturers of similar or near-by products could create common reverse logistics and/ or remanufacturing to reach the sufficient volume. One option is to collaborate only in the core collection and to perform the remanufacturing itself, another to share resources also in internal remanufacturing. This kind of networks could be called "Industry-specific remanufacturing networks". Even if this option might look attractive, many companies consider it impossible because of competition, fear of losing brand or market position. However, there are examples of collaboration also between competitors. In some cases the collaboration only involves the collection of cores, like used ink cartridges in Japan [START_REF] Matsumoto | An analysis of remanufacturing practices in Japan[END_REF].

One of the SME case companies manufactures heavy machines and had identified the need for collaboration in remanufacturing and reuse of old products. The company is looking for partners in Central Europe to start the activity. In case of heavy products and low volume the sufficient volume could be achieved through collaboration in the same geographical areas. These networks could be called "Location-based networks". Sometimes also specific sites or "Remanufacturing parks" are created which may be operated by one or many partners, to remanufacture a wide range of products. In this collaboration, with high enough volumes, some partners could specialize on a definite remanufacturing process phase (disassembly, cleaning etc.) which could support the cost-efficiency. By extending and distributing the activities into several locations and fields the Remanufacturing park -idea could become a "Remanufacturing ecosystem".

Thus, it can be observed that as there is a large variety of products, there is also a large variety of potential collaborative networks in remanufacturing. It is not the same to remanufacture a high volume of low value components as low volume of high value products. The collaboration may support overcoming some of the challenges: for example the challenge of core collection, achieving sufficient volume and also balancing the supply and demand. It may also contribute to the accumulation of knowledge and experience regarding remanufacturing.

Conclusions and Way Forward

Remanufacturing can be seen as an ultimate form of recycling. Through remanufacturing, materials and energy can be saved and less waste is produced. At its best, a win-win-win situation is reached: the manufacturer can get additional income and profitable business, the customers get products with a lower price and with a quality guarantee, and the natural resources are used less. It should be noted that in addition to saving product value remanufacturing is already now but increasingly in the future able to add value to the remanufactured products. This is already done for example in engine or vehicle remanufacturing through improving energy efficiency and cutting emissions of engines.

Also benefits at the level of society are seen as remanufacturing can provide industrial employment in skilled jobs and may create new opportunities supporting the product lifecycle and its extension. As part of circular economy [START_REF] Macarthur | Towards a circular economy. Economic and business rationale for an accelerated transition[END_REF], remanufacturing can support sustainable re-industrialization.

To progress in circular economy, actions on several levels are needed. These may include governmental and legal actions, like environmental standards, waste penalties and incentives from taxation. At the company level barriers and challenges need to be solved. As a whole, the awareness and knowledge about remanufacturing needs to be built and disseminated. However, it is important to understand that going to circular needs systemic changes in product design, customer attitudes, business models and value networks. These will be further studied in the Finnish national DemaNET project.

Fig. 1 .

 1 Fig. 1. Remanufacturing processes

I. Karvonen, K. Jansson and M. Uoti

Acknowledgement

This work has been partly funded by the Finnish Funding Agency for Technology and Innovation (Tekes) Green Growth program.


Luis M Camarinha-Matos

Filipa Ferrada

Ana Inês Oliveira

Interplay of Collaborative Networks in Product Servicing

Keywords: Collaborative networks, service-enhanced products, cloud computing

Application contexts such as the support to service-enhanced products require the interplay of various collaborative networks along the product life-cycle. Based on the solar energy parks case, various long-and short-term networks are identified and their inter-dependencies briefly analyzed. A cloud-based collaborative environment is developed to support the various types of networks. Presented results are achieved in the context of the GloNet project.

Introduction

Most past works on Collaborative Networks have focused on a single network form, e.g. a Virtual Organization (VO). In some cases the interactions between two forms of network have been analyzed, namely the interactions between a Virtual organizations Breeding Environment (VBE) and the VOs created within that VBE [START_REF] Camarinha-Matos | A framework for computer-assisted creation of dynamic virtual organizations[END_REF]. Some application cases, however, require the interplay among several networks. That is the case of enterprise networks to support service-enhanced products [START_REF] Camarinha-Matos | Collaborative Business Scenarios in a Service-Enhanced Products Ecosystem[END_REF].

In this case, in addition to an underlying VBE, various VOs can be foreseen namely for product manufacturing, designing the business services to enhance the product, providing multi-stakeholder composite services, etc. The reason for this need is that different stakeholders play a role at different stages of the product life-cycle. The collaborative efforts in each stage have a different purpose, and are carried out by different groups of members, although some members might be common to various networks. The life-cycles of the various networks and their duration are also different. For instance, while a service design / service co-creation VO is short-term, a service provision VO might have a long duration accompanying the life of the product. The service provision VO might include some members of the service design VO but in any case some inheritance mechanism between the two needs to be established.

On the other hand, in the context of a collaborative network various other formal and informal networks may emerge. Formal networks are regulated by explicit contracts or agreements. For instance, during the operation phase of a product, and thus in the context of its service provision VO, a need for a new service might be detected, what might trigger the formation of a temporary VO for the co-creation / codesign of the new service. Informal networks, which do not involve any formal contract, emerge as "aggregations" of entities that share some common interest, often a case of communities of practice or social networks. These networks are often seen as the glue that holds together cross-functional process improvement initiatives or the seed for product / service co-innovation processes [START_REF] Cross | Six Myths About Informal Networks -and How To Overcome Them[END_REF].

Understanding the interactions and dependencies among multiple collaborative networks is thus an important research challenge. This work aims at contributing to this challenge through a service-enhanced product case study conducted in the context of the GloNet project.

Related Areas

In the areas of complex networks and social networks analysis (SNA) the concept of overlapping sub-networks or communities is widely addressed. In recent years, considerable effort has been put on developing algorithms for overlapping communities' detection [START_REF] Xie | Overlapping Community Detection in Networks: the State of the Art and Comparative Study[END_REF], [START_REF] Chen | Detecting overlapping communities of weighted networks via a local algorithm[END_REF], [START_REF] Rees | Overlapping Community Detection by Collective Friendship Group Inference[END_REF], [START_REF] Orman | Qualitative comparison of community detection algorithms[END_REF]. The notion of community in this area, although not very well defined, typically represents a cluster or group of nodes that interact with each other more frequently than with those outside the group. As such, the aim of community detection algorithms is to identify groups of nodes more densely interconnected relatively to the rest of the network, i.e. resorting to information encoded in the graph topology.

Unfortunately, the notion of network in these areas, although conceptually attractive due to the clear mathematical properties that can be associated to the graph representation, also presents some limitations when applied to collaborative enterprise networks. For instance, the links between nodes are typically of the same kind, abstracting some form of connection (e.g. information interaction). In collaborative enterprise networks, the interactions among network members can be of very diverse types e.g. control relations, reporting relations, information flow relations, material flow relations, etc. Some approaches in SNA try to capture this diversity of relations through the notion of multiplexity, which comes from early literature in the area based on the realization that human relationships are normally multiplex or multi-stranded. It was also considered that a multiplex relation is stronger than a uniplex relation because it contains more than one basis for interaction [START_REF] Skvoretz | Reciprocity, Multiplexity, and Exchange: Measures[END_REF], which led then to the notion of relation's strength. But such simplistic notion does not fully capture the individual semantics of the various relations and as such does not adequately support management strategies for the networks. In spite of some works on multiplex networks, the underlying mechanisms of multiplexity remain poorly understood [START_REF] Ferriani | The social and economic bases of network multiplexity: Exploring the emergence of multiplex ties[END_REF]. One interesting attempt to analyze multiplexity in the context of inter-organizational networks, and particularly to understand the role of social and economic ties in the formation of dense multiplex ties is the work of Ferriani et al. [START_REF] Ferriani | The social and economic bases of network multiplexity: Exploring the emergence of multiplex ties[END_REF].

The methods explored in the areas of complex networks and SNA certainly have applicability in various problem areas, namely when basic data on nodes and links exist and the purpose is to extract / discover structural properties. In the case of collaborative enterprise networks however, the "starting point" and the granularity of the analysis are usually different. The problem is not so often to identify the existence of a network / community and its members; the members are often known and the membership is established through some "contract" or agreement, which reflects some common objective. Within such collaborative group, many interactions of different nature might occur but they are not always known a-priori, or at least, it is not the existence of data on such interactions that lets us identify the existence of the CN. In this sense, there are fundamental differences in the scope and approaches of the two areas.

The challenge in CNs is not to study the links/ties and their structural properties (or even how they emerge) -which are typical of a "link-oriented analysis" -but rather to progress on understanding aspects such as: Membership dependencies, time dependencies, purpose / goal dependencies, and inheritance dependencies between networks and also their supporting environments.

Service-Enhanced Products Case

The notion of service-enhanced product, also known as product-service, resulted from the need to increase product differentiation and the value of product offers. By associating business services that add value to the products, greater forms of differentiation can be achieved and new business opportunities generated since buyers of manufactured products increasingly want more than the physical product itself [START_REF] Shen | Research on Organization Mode Selection of Service-enhanced Manufacturing Enterprise[END_REF].

After decades of industrial decline, due to deliberate policies that advocated an exclusive move toward a service-oriented society, while neglecting the production of tradable goods, many countries have lost part of their industrial competitiveness in the manufacturing sector. The service-enhancement of products, and particularly the introduction of knowledge-based services, will likely help regaining competitiveness and facilitate some form of sustainable reindustrialization. Ties with end-users and local suppliers are vital in manufacturing supply chains, adding not only valuable know-how and multidisciplinary expertise while better fitting customer needs, but also increasing potential access to new markets. The agile formation of service provision networks associated to customized products and the effective involvement of the customer and local stakeholders allows for both (1) opening opportunities for manufactured goods combined with high value added services, and (2) an optimized mobilization of resources and competencies from different geographical regions. Furthermore, this approach will contribute to a transformation from a resourceintensive to a knowledge-intensive industry.

In line with this trend, GloNet, a project funded under the Factories of the Future program of the European Commission, aims at supporting complex, highly customized and service-enhanced products through collaboration with customers and local suppliers [START_REF] Camarinha-Matos | Collaborative Networks in Support of Service-Enhanced Products. Adaptation and Value Creating Collaborative Networks[END_REF]. The project assumes that collaboration and co-innovation in business services, supported by Internet and cloud computing, open new perspectives of value creation in this context. GloNet started in September 2011 with a planned duration of 3 years, and involves the following organizations: CAS (Germany), UNINOVA (Portugal), University of Amsterdam (Netherlands), iPLON (Germany), SKILL (Spain), Steinbeis (Germany), KOMIX (Czech Republic), and PROLON (Denmark). The main use case in GloNet focuses on the production and life cycle support of solar energy parks [START_REF] Afsarmanesh | ICT Requirements Analysis for Enterprise Networks Supporting Solar Power Plants[END_REF]. The primary aim is thus to develop a solution to promote and facilitate collaboration among partner companies in this industry, while improving the process of designing, developing, monitoring and controlling solar plant installations. In addition to this use case, and in order to extend the applicability of GloNet results, other domains with similar abstract characteristics, such as building automation and physical incubators of enterprises, are also considered.

The effective development and life-cycle support of service-enhanced products in these domains involve the interplay of different forms of collaborative networks (Fig. 1), including long-term strategic networks and goal-oriented, short-and long-term networks, comprising a wide variety of stakeholders and roles. In summary: Manufacturers' network -a long-term alliance that typically involves product / project designers, manufacturers, service providers, and some support entities, configuring a kind of virtual organizations breeding environment (VBE) [START_REF] Camarinha-Matos | On reference models for collaborative networked organizations[END_REF].

Long-term strategic networks Customer Network

Goal-oriented networks

Customer "network"-or customer related community -involving, besides the customer, local non-critical components suppliers, services providers, and a variety of support entities. Although this group might not be well organized and structured, it shares some minimal bonds like geographical vicinity, culture, business environment, legal regulations, etc. Product servicing network -a long-term VO organized to provide integrated or composite (multi-stakeholder) business services along the product lifecycle. In the case of the solar energy domain, an example of such network can include a monitoring and supervision company, maintenance companies, training provision entities, etc. This network needs to work in close interaction with the customer and other local stakeholders, namely regulators, utility companies, insurance companies, etc.

Service co-creation network -a dynamic (temporary) virtual organization (VO) involved in the design and development of new business services associated to the (physical) product. Since this area is the least developed, creation of new business services typically requires a co-innovation process carried out by a temporary consortium involving a number of participants selected from the Manufacturers network and Customer network or Product Servicing network.

Table 1 summarizes the main characteristics of these networks, based on the analysis of the solar energy parks use case.

Table 1. Summary characteristics of networks involved in service-enhanced products

Network Aspects Description

Manufacturers' network

Purpose

To jointly acquire new businesses (products and associated services).

Membership

Time

Long-term alliance (a kind of VBE)

Inheritance

The product portfolio of this VBE will integrate the outcomes of the various product development VOs and service co-creation VOs.

Customer's "network"

Purpose

As it is not a formal network, it does not have a direct goal; nevertheless, the general sustainability of the associated region can be seen as a common goal.

Membership

In the solar parks case: Customer (owner), Utility company, Lending organization, Government agencies, Insurance companies, Operation & maintenance companies, other suppliers, etc.

Time

Long-term community

Inheritance

It has access to the benefits of the product and its associated services.

Product development network

Purpose

To design and manufacture a new customized product.

Inheritance

The outcome of this VO will be inherited by the productservicing VO and will become part of the product portfolio of the manufacturers VBE.

Product Purpose

To provide integrated (multi-stakeholder based) business servicing network services along the life of the product.

Membership Example: Operation & maintenance companies, Monitoring & Control companies, Utility company, etc.

Time

Long-term VO

Inheritance

It has access to the results of both the product development VO and service co-creation VO.

Service cocreation network

Purpose

To design a new service for the product, following a cocreation process.

Membership It might include members from the product development network or from the product servicing network (depending on the time of launching), combined with some elements from the customer's network, including the customer.

Time

Short-term VO. Different service co-creation networks can be launched during the operation phase of either the product development VO or the product servicing VO, according to identified needs for new services.

Inheritance

The outcome of this VO (the service design) will be inherited by the service provision VO. In case the service is generic enough to be exploitable in other products, it is also inherited by the manufacturers' VBE.

Support Environment

In order to support the life-cycle and interplay of the various collaborative networks involved in service-enhanced products, an ICT support environment is developed in GloNet according to the general architecture illustrated in Fig. 2. This system consists of two high-level modules, namely:

Collaborative Networking Framework

Conclusions

The concepts and mechanisms originated in the CN area are nowadays penetrating many application domains. Furthermore, in various use cases we can identify a mix of long-and short-term networks, strategic and goal-oriented networks, and formal and informal networks. The coexistence and interactions among these multiple networks, often with overlapping structures and membership, raises new research challenges. As a contribution to better understand the interplay among diverse CNs, and to support their life-cycles, GloNet project is focusing on the needs of service-enhanced products and their associated servicing networks. The proposed collaboration environment was designed to also cope with the needs of involving local stakeholders, close to the customer, in the process of co-creation of new services. The actual validation of the proposed solutions in the context of solar energy parks is an ongoing work.

Fig. 1 -

 1 Fig. 1 -Mix of collaborative networks in product development and servicing

  In the solar parks case: Project development firms, Engineering, Procurement & Construction (EPC) companies, PV equipment manufacturers, Monitoring & Control companies, Construction & Commissioning companies.

Fig. 2 -

 2 Fig. 2 -GloNet system architecture

Fig. 5 -

 5 Fig. 5 -BPMN diagram for the selection of goal-oriented VO partners

User Interface Co-working Environment Collaborative Networks Management Environment Cloud-based Platform

	VBE Trust	Value Systems
	Management	Alignment Analysis
	Services Invocation	Shared Resource	SW Services	Process Modeling &
	Management	Management	Cataloguing Editor	Monitoring Support Tool	Environment	Development

VBE Management -Advanced VBE Base Mgmt LONG-TERM STRATEGIC NETWORKS Authorized Information Sharing Cloud Computing Support Information / Knowledge Management SERVICE-ENHANCED PRODUCT SUPPORT Product Configurator Tool Product Portfolio Support Tool Service-Enhanced Product Ordering Editor Service Registering, Discovering & Monitoring Editor Collaboration Solution Space Interface Business Services Provision Space Interface PLATFORM BASIC COMPONENTS PLATFORM SERVICES SUPPORT STAKEHOLDERS SPACE INTERFACE GOAL-ORIENTED NETWORKS VO Base Mgmt VO Management -Advanced

			User interface portals for
			the product/service
			creation and business
			services provision phases
			Co-working environment
			comprising a set of
			support mechanisms for
			the management and
			operation of service-
			enhanced products
			VBE Management -basic
			and advanced
			management services
	Dynamic Consortia	Risk Forecasting	along the VBE life-cycle
	Creation	and Management	VO Management -
			creation, operation and
			management services
			along the VO life-cycle
			Cloud-based
			functionalities for
			supporting the
			development and usability
			of collaborative
			functionalities needed for
			GloNet

Acknowledgments. This work was funded in part by the European Commission through the GloNet project (FP7 programme). The authors also thank the contributions from their partners in this project.

Cloud-based Platform -which aims at providing the enabling cloud services for giving support to the development and usability of collaborative functionalities needed for GloNet. Collaborative Networking Framework -which aims at providing functionalities needed for collaboration spaces and to support the different forms of collaborative networks, comprising a wide variety of stakeholders that get together in order to create service-enhanced products. These two high-level modules of the architecture are then divided into a set of layers.

One of the main components of the CN Framework is the VBE management subsystem, whose functionalities, inspired on ECOLEAD [START_REF]Methods and tools for Collaborative Networked Organizations[END_REF], are illustrated in Fig. 3.

BASE MANAGEMENT SUB-SYSTEMS VBE Competences Management

Fig. 3 -VBE Management functionalities

Another important component is the VO management system, to support the various goal-oriented networks. As an example of the modules included in this component, the functionalities to support the VO creation are illustrated in Fig. 4.

DYNAMIC CONSORTIA CREATION SUB-SYSTEMS VBE Members Competences Analysis

LONG-TERM STRATEGIC NETWORKS SUB-SYSTEM

Fig. 4 -VO Creation functionalities

On top of these components, GloNet introduces a co-working environment that comprises a set of support mechanisms for the management and operation of serviceenhanced products, including product and service configuration, product portfolio management, user interfaces, etc. At the user interface layer there are two portals: the Collaboration Solution Space Interface that aims at providing an access point through which manufacturers, local suppliers and customers "meet" to co-create the product and its associated services; and the Business Services Provision Space Interface that aims at providing an access point to the "registry" of the products along their life-cycle through which customers can have access to the specific services associated to the customized product.

The GloNet system is developed on top of a cloud-based platform. Besides the initial lower cost in setting up the cloud's hardware as compared to conventional physical local setups at every company, factors such as ease of servicing, upgrading and maintaining suggest a cloud-based infrastructure as a promising environment for this context. There are, however, various aspects to be better assessed, e.g. vendor lock-in, integration of components running in different infrastructures, and the associated business models.

Considering the above support functionalities, Fig. 5 illustrates the process of selecting partners for a VO creation. In this example, potential partners are selected from both the VBE (e.g. Manufacturer's network) and the Customer's "network" (indicated as External Interested Stakeholders in the diagram).


Ioannis Patiniotakis

Nikos Papageorgiou

Dimitris Apostolou

Yiannis Verginadis

Gregoris Mentzas
email: gmentzas@mail.ntua.gr

Collaborative Process Flexibility Using Multi-Criteria Decision Making

Keywords: Collaborative Processes, Flexibility, Adaptation, MCDM, SANs

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

Introduction

In today's agile business environment, information systems should be able to model business needs in a flexible manner in order to be effective. It must allow domain experts to model business systems with means that are intuitively comprehensible using concepts that are familiar to them, such as goals and actions for achieving them. Goal-orientation is based on separating the declarative statements and defining desired system behavior, thus hiding from business users the low-level system details [START_REF] Mylopoulos | From Object-Oriented to Goal-Oriented Requirements Analysis[END_REF]. This flexibility is even more imperative when business information systems should deal with and support collaborative processes. Collaborative Process flexibility can be seen as the ability to deal with both foreseen and unforeseen changes in a collaborative process, by varying or adapting promptly those parts that are affected.

Situation Action Networks (SANs) is a modeling framework that can be used for defining business systems' reactions to significant situations with the purpose of fulfilling or satisfying a goal [START_REF] Patiniotiakis | Dynamic Event Subscriptions in Distributed Event Based Architectures[END_REF]. SANs are hierarchical goal-directed models that comprise nodes with specific semantics, presenting possible decomposition paths from goals into subgoals and primitive actions. Goals are related to situations that trigger their activation and reactions that should be performed towards achieving these goals when certain conditions are met (Fig. 1). SANs are modeled and executed by the SAN editor and SAN engine, respectively. SAN engine can enable automatic search for new goals when specific circumstances, i.e. situational and contextual settings, arise and recommend actions in order to satisfy the currently active goals. The SAN framework has been coupled with an aspect-oriented extension of BPMN2.0 in order to enable the execution of BPMN2.0 processes and support business process adaptation [START_REF] Patiniotiakis | An Aspect Oriented Approach for Implementing Situational Driven Adaptation of BPMN2.0 Workflows[END_REF]. In that work, SANs are used to monitor the process execution environment and describe meaningful reactions to problems. Based on these monitoring capabilities, SANs are able to detect process execution problems (e.g. violation on quality "threshold") and trigger lookup for suitable adaptation actions by using a reasoning mechanism. The implementation of the recommended adaptation is based on aspect-oriented programming (AOP) techniques [START_REF] Charfi | AO4BPEL: An Aspect-Oriented Extension to BPEL[END_REF]. We note that the actual SAN modeling is not considered trivial and dictates for an editor that is domain expert and is capable for conceptually validating the outcome.

Despite the intuitiveness of goal-orientation for business users, modelling a goaloriented business process to its full detail can be tedious and time-consuming. Furthermore, not all process parameters may be known a priori, or large numbers of alternative goal decompositions are possible, thus making the development of a detailed model impractical or even impossible. In order to remedy these issues, process modeling flexibility with SANs can be improved with techniques that enable them to dynamically "choose" the required or desired detailed goal decompositions.

In this paper, our research objective is to extend the SAN modeling framework with the appropriate constructs and corresponding methods in order to alleviate a part of the modeler's effort during the design of BPMN2.0 processes and increase their run time flexibility.

Different kinds of flexibility are needed during the life cycle of a business process. There have been numerous studies of flexibility in business processes oriented systems, both in terms of the factors which motivate it and the ways in which it can be achieved. The following papers cover extensively the literature on both the notion of process flexibility as well as design and evaluation approaches of flexible process-aware systems [START_REF] Snowdon | On the Architecture and Form of Flexible Process Support[END_REF], [START_REF] Soffer | On the Notion of Flexibility in Business Processes[END_REF], [START_REF] Regev | Taxonomy of Flexibility in Business Processes[END_REF], [START_REF] Carlsen | Evaluating Flexible Workflow Systems[END_REF], [START_REF] Heinl | A Comprehensive Approach to Flexibility in Workflow Management Systems[END_REF], [START_REF] Kumar | Defining Requirements for Business Process Flexibility[END_REF]. Our approach focuses on relieving the modeler from having to a priori map situations to specific actions that should be enacted when the situations occur. Instead, a pool of primitive actions or even linked SANs can be mapped at design time with situations. These pools may be dynamically updated at run time. The framework extension involves the capability to automatically select appropriate primitive actions based on real time evaluated criteria using Multi-Criteria Decision Making (MCDM) methods. We formally present this extension, we discuss the necessary SAN engine extensions and we conclude with an illustrative scenario that exhibits the flexibility improvements.

Flexibility Approach

We introduce two new node types in the SAN formalism, named Abstract Action and Action Pool that enable dynamic (at runtime) "choice" over the required or desired goal decompositions. This dynamic behaviour of SANs along with the use of AO4BPMN2.0 (aspect-oriented extension of BPMN2.0, presented in [START_REF] Patiniotiakis | An Aspect Oriented Approach for Implementing Situational Driven Adaptation of BPMN2.0 Workflows[END_REF]), induces flexibility in collaborative business processes.

Abstract actions are leaf nodes in SANs that when visited (during SAN traversal), they determine on-the-fly the tasks they should be performed, selecting them from a repository of alternative actions, called Action Pool. For that purpose search and selection multi-criteria decision making methods (MCDM) are specified beforehand. In our implementation we have used the Linguistic Ordered Weighted Average (LOWA) [START_REF] Herrera | Direct approach processes in group decision making using linguistic OWA operators[END_REF] method that acts on linguistic variables, such as words or sentences in a natural language, and produces (linguistic) ranking. The tasks can range from primitive actions up to whole SANs. Abstract action nodes replace themselves with the task(s) that are automatically selected from an associated action pool, based on the search and selection method and resolution policy used. Abstract Action nodes must be annotated with metadata providing the necessary configuration for the search and selection methods. These metadata specify the criteria that will be used along with their weights. Additional metadata control the ordering, the size of results list and filtering ("LOWA Criteria", "Ascending Order", "Results Count", Allowed Values", "Results Filter", "Mapping"). All the annotations needed both in abstract actions nodes and in action pools are inserted through the SAN editor.

An Action Pool contains several possible alternative decompositions for an abstract action. Normally the contained items should all provide decompositions for the same purpose or goal. An action pool can be used by more than one abstract action, possibly in different SANs. It's worth noting that Action Pools can either be predefined sets of decompositions, or they can be retrieved / generated at runtime from an online service, for instance databases or web services. Action Pools must be annotated firstly with criteria parameters. Any metadata defined for annotating an Action Pool actually denote mandatory metadata that should also appear in the action pool items. Some or all of the action pool metadata can be used as search and selection criteria in LOWA method or any other MCDM methods that might be defined in the future. All action pool Items must be annotated with values, pertaining to the criteria defined in action pool. These values are used to calculate the average scores of action pool items using LOWA. The values can either be linguistic terms, numeric or text values. In case of linguistic terms a mapping parameter is used for specifying how the linguistic terms map to actual criteria values.

A Search and Selection Method is responsible to scan all action pool items, examine their properties and figure out which of them fit the specific purpose of the abstract action node. When more than one action pool items fit the purpose, it is again the responsibility of search and selection method to pick the best one. In some cases, however, it is acceptable (or even desired) to select the top N best items or all matching items. In such cases an ordering is required. We used the multi-criteria decision making method LOWA for performing this ranking of the action pools items.

A Resolution Policy is needed when the search and selection method returns more than one items. It is responsible to make the final selection of the item that will be used to replace the abstract action node. It is allowed to select more than one item, in which case it must define the way the items should be combined. For the time being five resolution policies have been defined: i) use the item at the 1st place (best ranked item) in the results list, ii) select an item from the results list randomly, iii) combine all matching items into a "Parallel Any" action, iv) combine all matching items into a "Parallel All" action, v) combine all matching items into a "Parallel Timeout" action.

Algorithm and Implementation

LOWA has been used as MCDM method to select and rank the action pool items, using linguistic terms. This method accepts the following input arguments from SAN engine core: i) reference to the "owner" abstract action, ii) reference to the specified action pool, iii) reference to the local context. These are references to various SAN model entities that contain configuration data that the method needs in order to work appropriately. Configuration data are stored as metadata annotations on the arguments passed to SAN model entities. Using the above input, the following algorithm (Table 1) is implemented by our system in order to properly use the abstract action capabilities of SAN formalism. The dynamic decomposition functionality described has been incorporated in the reference SAN engine by extending its base API and implementing extensions at the traversal engine and SAN repository (Fig. 2). All components along with their extensions were coded using Java programming language. The Adaptation Manager component handles the coupling of SAN engine with the aspect-oriented extension of BPMN2.0 (presented in [START_REF] Patiniotiakis | An Aspect Oriented Approach for Implementing Situational Driven Adaptation of BPMN2.0 Workflows[END_REF]) in order to enable the execution of BPMN2.0 processes and support business process adaptation. Its primary role is to closely monitor the execution of process instances and activate the corresponding advices based on SAN traversal (further details can be found in [START_REF] Patiniotiakis | An Aspect Oriented Approach for Implementing Situational Driven Adaptation of BPMN2.0 Workflows[END_REF]).

Illustrative Scenario

We use the nuclear crisis management scenario [START_REF] Patiniotiakis | An Aspect Oriented Approach for Implementing Situational Driven Adaptation of BPMN2.0 Workflows[END_REF], where a large quantity of radioactive substance is accidentally released in the atmosphere. A number of mitigating actions take place based on a predefined collaborative process that involves several different actors, authorities and services (e.g. police, military, fire brigade, national institute for radioprotection and nuclear safety, representatives of national authority etc.). In this scenario instead of pre-modeling (in one SAN) all possible adaptation actions, we use the notion of abstract action and action pool in order to be able to select adaptation advices at run time based on the current context.

The SAN (Fig. 3) designed, takes advantage of an action pool and instead of having a pre-designed recommendation process of generating advices, when "Study Advice" gets delayed, the abstract action "Recommend of weaving a Wf Advice" is used. This abstract action is associated with a number of alternative advices that could be suggested, based on the current context information. In this scenario Radiation Level and Weather Conditions are used as selection criteria for the search and selection method. The contextual values of these two criteria are derived from the field and meteorological event streams, and they are expressed as linguistic terms taking one of the values: Normal, Notify, Alert, Dangerous and Critical. The SAN Designer can set the weights for these criteria (e.g. 70% Radiation Level, 30% Weather Conditions). We use an Action pool that includes items that generate adaptation advices (i.e. recommendations): 1. Advice 2 without interrupt (Radiation Level: ALERT, Weather Conditions: ALERT). Since a dangerous or critical situation has not been detected yet, the involved actors can afford to wait for this study to be finished before the Representative of the National Authority asking for additional clarifications.

When both the "study advice" and "study clarifications" tasks finish, the normal workflow execution can proceed. The Advice 2 involves the weaving after the "study advice" task the following sequential ones: "Ask for clarifications", "Wait and receive clarifications", "Study clarifications". In this case the reactions should be accelerated, so the task "Study Advice" is interrupted and the advice 2 is weaved.

3. Advice 4 (Radiation Level: DANGEROUS, Weather Conditions: NORMAL). Although, a dangerous situation has been detected, there is some time (since weather conditions are normal) to consider carefully the proper reactions. The important thing in such situation is to take the best possible decision that is why advice 4 is weaved after the "Study Advice" task has been completed with a delay (no interruption this time). The Advice 4 involves the weaving after the "study advice" task the following sequential ones: "Ask for activity report", "Wait and receive activity report", "study activity report".

4. Do Nothing -normal workflow execution (Radiation Level: NOTIFY, Weather Conditions: NORMAL). Although SAN has detected a significant delay in the "Study Advice" task, it is not meaningful to weave any adaptation action since the weather conditions are normal, thus the radiation cloud will not move fast. This means the there is the necessary time for the involved actors to take the correct decisions.

The following figure presents recommendations generated by our system, and published as events, using the aforementioned setup.

Conclusions

In this paper, we presented an extension of the Situation Action Network (SAN) modelling framework in order to introduce run-time flexibility in collaborative processes. The extension enables dynamic decomposition of SANs allowing for abstract definition of SANs at design time. Dynamic decomposition enables more flexible and modular modelling, since the decomposition details can be modelled separately from the main problem. This separation facilitates SANs' reuse and improves the usefulness and applicability of each main model. On the other hand, the decomposed models (contained in Action Pools) can be treated as runtime libraries and also be re-used. Further, our approach implements an abstraction layer over the main modelling process by removing the decomposition search, selection and execution method details. Finally, decompositions for various purposes, in the form of action pools, can be developed and provided by third parties, or collaboratively be built from a group of designers. Continuing this work on flexible SANs, we plan for an extensive evaluation of our approach where any lag or limitations in terms of recommendations speed, will be measured.

Fig. 1 .

 1 Fig. 1. Basic Modeling Primitives of SANs

Fig. 2 .

 2 Fig. 2. Conceptual Architecture

Fig. 3 .

 3 Fig. 3. SAN deployed for Collaborative Process Flexibility 2. Advice 2 with task interruption (Radiation Level: CRITICAL, WeatherConditions: DANGEROUS). In this case the reactions should be accelerated, so the task "Study Advice" is interrupted and the advice 2 is weaved.

Fig. 4 .

 4 Fig. 4. Recommendation to weave Advice 2

Table 1 .

 1 SAN Search & Selection list 'items' with 'lowa_score ≠ filter' order elements of list 'items' based on 'lowa_scores' with direction 'order' remove elements of list 'items' after position 'count'

	Algorithm SAN Search & Selection
	Require: self reference to abstract action node
	items get_action_pool_items( get_action_pool(self) )
	criteria get_criteria(self)
	allowed_values	get_allowed_values(self)
	mapping get_mapping(self)
	weights	get_criteria_weights(self, criteria)
	for each item I in items do
	values	empty list
	for each criterion C in criteria do
		item_value get_item_value(I, C)
		if mapping ≠ Ø then
			item_value translate_value(mapping of C, item_value)

Acknowledgments. This work has been partially funded by the European Commission under project PLAY (Grant FP7-258659). The authors would like to thank the project partners for their advices and comments regarding this work.


Keith Griffin
email: kegriffi@cisco.com

Maciej Dabrowski
email: maciej.dabrowski@deri.org

John Breslin

Real-time Data Aggregation in Distributed Enterprise Social Platforms

Keywords: Enterprise Social Networks, Real-time systems, Personalization

The widespread use of social platforms in contemporary organizations leads to the generation of large amount of content shared through various social tools. This information is distributed and often unstructured, making it difficult to fully exploit its value in enterprise context. While Semantic Web technologies allow for publishing meaningful and structured data, major challenges include: (1) real-time integration of distributed social data, and (2) content personalization to identify relevant pieces of information and present them to users to limit the information overload. This research in progress paper draws from an enterprise use case and discussed practices in real-time integration of social data in distributed social platforms. We propose to combine Semantic Web technologies with standardized transport protocols to provide efficient and open source layer for aggregation of distributed social data in an enterprise. We also show how our component can facilitate development of personalised social platforms.

Introduction

The employees of contemporary enterprises are often distributed across departments and geographical locations, use different information systems, and offer a wide variety of skills and expertise to the organisation. In such environment, efficient delivery of relevant information to interested peers can be challenging. To help alleviate this problem, Semantic Web technologies [START_REF] Berners-Lee | The Semantic Web[END_REF] have gained popularity in the corporate world, enabling transparent provision of structured and meaningful data with the use of lightweight and standardized vocabularies such as FOAF 1 or SIOC 2 , allowing to model enterprise data in RDF 3 . The combination of Semantic Web technologies with social platforms in organisations led to the "Social Semantic Enterprise" [START_REF] Passant | Semantic Web Technologies For Enterprise 2[END_REF] that can profit from these trends by efficient, close to real-time aggregation of structured and meaningful data.

Social platforms that enable personalized information access in an enterprise environment require an infrastructure and algorithms that address many complex challenges: [START_REF] Berners-Lee | The Semantic Web[END_REF] aggregation and integration of data from different information systems/social platforms in the IT landscape of the enterprise is required, [START_REF] Bhide | Adaptive push-pull: Disseminating dynamic web data[END_REF] provision of new algorithms that are independent of the domain and/or the source of the data to allow efficient personalization, (3) effective presentation and feedback mechanism to improve acceptance and quality of delivered information. This paper focuses mainly on the first challenge, and discusses how the contribution presented here can facilitate solutions to the second and third problems. We argue that while Semantic Web technologies provide rich data integration capabilities [START_REF] Shadbolt | The semantic web revisited[END_REF], there is a need to ensure that the integration of information from the vital sources available in an organization can be performed in, or close to, real-time. This is especially relevant in large organizations, where social platforms can be deployed in different geographical localisations nevertheless they need to interact instantaneously. Current approaches may not only delay the information flow but also negatively impact overall efficiency in many scenarios.

This paper gives an overview of work focused on enabling real-time aggregation and integration of social content published through distributed social platforms across and beyond an organization. We discuss how Semantic Web technologies and realtime instant messaging protocols can be used for efficient and quick aggregation of content between distributed social platforms according to corporate information management policies and with the use of existing real-time communication protocols.

Distributed Social Platforms

Organizations build and maintain many information systems to manage large volume of content published and consumed by knowledge-intensive workers [START_REF] Gold | Knowledge management: An organizational capabilities perspective[END_REF]. Such environments involve many actors sharing and consuming information within a large network that is often distributed across various departments (see Figure 1) or even geographically. This shift requires new approaches for delivery of timely and relevant information in a close-to-real-time manner across such peer-to-peer [START_REF] Oram | Peer-to-Peer: Harnessing the Power of Disruptive Technologies[END_REF] networks. Many initiatives [START_REF] Weiss | Wooki: a p2p wiki-based collaborative writing tool[END_REF][START_REF] Du | Dtwiki: a disconnection and intermittency tolerant wiki[END_REF][START_REF] Mukherjee | Piki -a peer-to-peer based wiki engine[END_REF] focus on building collaborative tools (e.g. wikis) that combine the benefits of mass collaboration with the intrinsic qualities of peer-to-peer networks, such as scalability or fault-tolerance. Although knowledge workers utilize many collaboration tools (e.g. blogs, wikis), crucial information is often not managed effectively [START_REF] Sabherwal | Business Intelligence: Practices, Technologies, & Management[END_REF] what affects efficiency and generates additional spending. To address this concern, organizations attempt to sustain information exchange through utilization of social networking tools both internally and externally. Once the social platform is operational and social connections are established, it is important to gather and reuse information available in this network. Thus, a distributed social network requires efficient information aggregation and delivery tools to allow for timely updates and retrieval of relevant content [START_REF] Trams | Waeving a distributed, semantic social network for mobile users[END_REF]. To address this challenge, the Semantic Web practitioners propose to use RDF to capture social data [START_REF] Shinavier | Real-time semantic web in <=140chars[END_REF] and integrate RDF content across the organization. This is possible thanks to tools that provide means for building scalable distributed RDF repositories based on P2P networks, for example RDFPeers [START_REF] Cai | Rdfpeers: A scalable distributed rdf repository based on a structured peer-to-peer network[END_REF]. Indeed, the growing amount of information available in the form of RDF that needs to be accessible by distributed peers in an organizational network requires mechanism for distributed querying [START_REF] Quilitz | Querying distributed rdf data sources with sparql[END_REF] or replication [START_REF] Schandlands | A framework for adaptive RDF graph replication for mobile semantic web applications[END_REF]. Consequently, there is a need to tackle many aspects related to the dynamism of RDF data ("dataset dynamics" [START_REF] Umbrich | Dataset dynamics compendium: A comparative study[END_REF]), including change management. These issues are addressed in approaches for synchronization of RDF data (e.g. RDFSync [START_REF] Tummarello | Rdfsync: efficient remote synchronization of rdf models[END_REF]) that model and distribute changes in RDF models to the peers in large networks.

Distributed social platforms pose challenges related to efficient aggregation and delivery of information to relevant employees. The generic categorizations of models for communication and content/event exchange in a distributed environment differentiates pull and push approaches. The pull model involves an initial request from the (active) client that is responded by a (passive) server and is one of the most commonly used communication patterns in distributed networks. Polling is a mechanism related to pull model, which relies on clients actively sampling the server status through repetitive requests. Polling is considered resource expensive and scales poorly [START_REF] Eugster | Distributed Asynchronous Collections: Abstractions for Publish/Subscribe Interaction[END_REF] as frequent polling may lead to inefficient usage of resources, but infrequent requests "may result in delayed responses to critical situations" [START_REF] Eugster | Distributed Asynchronous Collections: Abstractions for Publish/Subscribe Interaction[END_REF]. Further, many scenarios require asynchronous delivery of events for better performance and scalability. Long Polling, introduced to address these limitations, is an approach based on the request-response model in which the server holds the request open until the response is available (or when the set timeout is reached) [START_REF] Griffinand | Evaluation of asynchronous event mechanisms for browserbased real-time communication integration[END_REF]. In contrast to the pull approach, the push model assumes a passive client that is notified of the occurrence of specific events upon a subscription to the server. The publish/subscribe (PubSub) interaction paradigm exploits the push model as it enables agents to subscribe to a particular event (e.g. content update), and to receive asynchronous notifications from the server/publisher when the event occurs [START_REF] Eugster | The many faces of publish/-subscribe[END_REF]. The advantages of the PubSub paradigm over the Polling approach lie in the optimization of the number of request, the required network traffic, and in the full decoupling in "time, space, and synchronization between publishers and subscribers" [START_REF] Eugster | The many faces of publish/-subscribe[END_REF]. Although the push approaches are gaining more popularity, the tools built using the pull paradigm are prevalent (see [START_REF] Bhide | Adaptive push-pull: Disseminating dynamic web data[END_REF] for a detailed discussion). However, with the expansion of the Semantic Web technologies, more focus is put on applications implementing the push interaction model. The task of real-time synchronization of RDF data requires both protocols and RDF description formats that allow concise data modelling and generate minimum amount of network traffic. In the next section, we present the scenario based on the problems faced by organizations with distributed social platforms and the generic requirements for integration of semantic social content and discuss these formats.

1 Use Case

Real-time aggregation of information published through various social platforms and collaboration tools in an organization lead to a number of problems and technological challenges. This is resembled in the use case described in this article (see Figure 1). Andrew, Bob and Cecilia are knowledge workers employed by a large organisation, however they work in different departments (CTO, IT, and marketing respectively) and use different social tools and platforms. In the current environment, they often must follow updates through various collaboration tools (e.g. wikis, confluence, enterprise microblogging) and corporate blogs of other co-workers to access content relevant to a given topic of their interest. While the use of RSS in this scenario is possible it implies regular querying of the information sources for updates, this approach does not allow for efficient integration of data across separated subdivisional networks with restricted access policies. Finally, modifications of content that has already been distributed are not possible. This example highlights the need for techniques enabling aggregation of social data with operations on data with fine granularity. Therefore, we argue that operations on data such as Create, Read, Update, or Delete (CRUD) [START_REF] Martin | Managing the database environment Martin[END_REF] should be possible to execute not only on the document, but as well on the single-statement level. The support for, and efficiency of, the execution of these operations form the basic requirements for social platforms aggregating data across distributed organizations in real-time. Further, social platforms should be capable of delivery of content to interested users independently of the platform they are using, as well as limit the content delivery to only subscribed users as well as through filtering. In the next section we give an overview of the existing RDF update formats.

Approach

Describing Social Data with Semantic Web

For some applications (e.g. social content), in particular when aggregation from various sources is required, content update can be represented as streams of RDF triples [START_REF] Shinavier | Optimizing real-time rdf data streams[END_REF]. Many applications in the Enterprise 2.0 are more stateful (e.g. presence management), thus require not only addition of the new content but also deletion/editing of existing information. Thus, RDF data integration techniques deployed in Enterprise 2.0 platforms should support not only addition, but also deletion and editing of existing content. Further, it is essential that the update operations should be done on the lowest possible level that is triple-level. Hence, we investigate a number of formats that provide social data modelling capabilities and fine-grained CRUD. Here we compare variety of existing formats including: SPARQL Update4 , Talis Changeset, the Graph Update Ontology5 , Guaranteed RDF Update format 6 , and Sesame RDF transactions.

The results of our previous work [START_REF] Dabrowski | Approaches for real-time integration of semantic web data in distributed enterprise systems[END_REF] indicate that Changeset and GUO consume significantly more network resources than the efficient formats (SPARQL Update and GRUF). Talis Changeset required roughly twice more resources (a 70% increase in case of GUO) to remove a tag from the description of an already distributed post. However, when more data is concerned in a single request (e.g. distribution of a newly published post), SPARQL Update provides the highest efficiency, followed closely by GUO and GRUF. Overall, the results indicate that, for the data provided, SPARQL Update combines many advantages with very low network usage and flexibility and as a W3C standard, SPARQL Update seems an appropriate format for describing RDF updates for real-time synchronization of distributed platforms.

Aggregating Social Data

The RDF update formats require a particular communication protocol [START_REF] Shinavier | Optimizing real-time rdf data streams[END_REF] to deliver content to appropriate recipients. For example, SPARQL/Update utilizes the SPARQL 1.1 protocol7 (with a HTTP binding) for managing RDF graphs, Changesets messages are distributed using a HTTP-based protocol 8 , and Sparql-PuSH [START_REF] Passant | sparqlpush: Proactive notification of data updates in rdf stores using pubsubhubbub[END_REF] uses the PubSubHubbub protocol 9 to notify subscribers about content updates using HTTP POST. Although some protocols enable maintenance of sessions between endpoints willing to exchange data (e.g. Session Initiation Protocol10 ), most are connectionless and based on HTTP, with exceptions such as XMPP PubSub that uses TCP connections maintained between the requests. These characteristics impact reliability of protocols and/or their ability to handle notifications to subscribers temporarily offline or over unreliable networks. A detailed comparison of various features (see Table 1) suggests that reliability, efficiency, security and extensibility of XMPP PubSub combined with its adoption in contemporary enterprises make this protocol an ideal choice for aggregation of social content modelled in RDF. Thus, XMPP PubSub and SPARQL Update are selected as a solution to the above-mentioned problem.

Proposed Solution

Based on the presented use case and the requirements we describe the architecture of the proposed solution. The XMPP server has the function of routing of the messages between the connected social platforms. In addition it provides an extensible platform that can process all information that it receives, for example to provide content personalisation through pluggable personalization components. As one or more platforms may be connected to a given XMPP server, the servers communicate with each other sending SPARQL Update messages embedded in XMPP PubSub stanzas. XMPP provides the infrastructure for connecting social platforms in a decentralised way and for sharing of knowledge between those social platforms. The server provides a central point for the connected social platforms to exchange XMPP messages. In case an existing XMPP server is used, it must implement the XMPP Publish-Subscribe extension (XEP-0060) 11 , which allows XMPP clients to subscribe to updates. In order to publish and receive aggregated content social platforms need to connect to the XMPP server via the XMPP client, a task that can be accomplished using an open source component 12 that allows easy integration.

Personalization

Our approach is designed having in mind the need for personalisation in enterprise social platforms. Being aware of the overwhelming amount of content published daily within the organization, users of social platforms require personalised access to information to limit the information overload. First the recommendation approach should take into account data from multiple sources. In addition, the approach should be applicable to any kind of social content: blog posts, microblog posts, wiki pages or even office documents could be recommendable items. The recommendation results should take relations between concepts/terms into account, so that slightly different views on the same concept can be handled. Further, the cold-start problem related to the initial lack of data for computation of recommendation should be avoided (e.g. in collaborative filtering, items which did not get any user ratings should be available as part of the recommendations). Such requirements make the selection of appropriate personalisation algorithm very difficult. The proposed solution allows for design and deployment of various personalization components that extend the XMPP server either through plugin mechanism, or using external components that process received messages. Our initial experiments (not in scope of this paper) prove that this approach is scalable, efficient and flexible enabling close to real-time personalised aggregation of social content from distributed social platforms.

Discussion

This article discussed challenges for efficient aggregation of cross-domain, multi source content in distributed enterprise social platforms. We argue that while Semantic Web technologies allow for publishing meaningful and structured data, major remaining challenges include: (1) real-time integration of distributed social data, and (2) content personalization to identify relevant pieces of information and present them to users to limit the information overload. This research in progress paper draws from an enterprise use case and discussed practices in real-time integration of social data in distributed social platform. We proposed to combine Semantic Web technologies and standard protocols already used in organisations to deploy instant messaging solutions to provide efficient and open source layer for aggregation of distributed social content. We also show how our component facilitates development of personalised social platforms.

Fig. 1 .

 1 Fig. 1. Users publish large volumes of information through disconnected enterprise social platforms. This valuable information may be hard to discover by other users lowering the value of knowledge capital in an organization.

Fig. 2 .

 2 Fig. 2. Aggregation of content through distributed XMPP infrastructure.

Table 1 .

 1 A comparison of the selected push protocols.

	Characteristics Bayeux/Comet Websockets	SLAP	SUP	XMPP PubSub	PUSH
	Transport Layer	HTTP	HTTP	UDP	HTTP(S)	TCP/XMPP	HTTP(S)
	Category	Both	Fat ping	Light ping Light Ping	Fat ping	Fat ping
	Interaction Style Long Polling	Push	Ping/Poll	Poling	Push	Push
	Latency	Low	Min.	Low	Low	Min.	Min.
	Secure	Yes	Yes	Yes	Somewhat	Yes	Yes
	Notifications

http://foaf-project.org/

http://sioc-project.org/

Resource Description Framework: http://www.w3.org/RDF/

http://www.w3.org/TR/sparql11-update/

http://webr3.org/specs/guo/

http://websub.org/wiki/GRUF

http://www.w3.org/TR/2009/WD-sparql11-protocol-20091022/

http://n2.talis.com/wiki/Changeset_Protocol

http://code.google.com/p/pubsubhubbub/

see RFC 3261 at http://www.rfc-editor.org/rfc/rfc3261.txt

http://xmpp.org/extensions/xep-0060.html

https://github.com/derixmpppubsub/derixmpppubsub/