João Bastos
email: joao.bastos@fe.up.pt

Valentina Franchini
email: franchini@gest.unipd.it

Américo Azevedo

Rosanna Fornasiero
email: rosanna.fornasiero@itia.cnr.it

Collaborative Networks Model for Clothing & Footwear Business Sector

Keywords: Reference Model, Supply Networks, Collaborative Networks; Clothing and Footwear

In clothing and footwear business sector, consumer needs and expectations of specific target groups -such as elderly, obese, disabled, or diabetic persons -are arising as challenging opportunities for European companies that are asked to supply small series of innovative and fashionable goods of high quality, affordable price and eco-compatible. This paper aims at propose a three level (strategic, tactical, and operational) reference model to support the Textile, Clothing and Footwear (TCF) collaborative supply networks in addressing the need for Fashionable and Healthy Clothing & Footwear products.

Introduction

The recent years have stressed the need to re-invent the concept of enterprise. Since 2008, with the global financial crisis coupled with the remarkable increase of oil and energy prices, the way to make business have changed dramatically. The flow of money decreased and consequently the flow of products and services have changed dramatically. Enterprise managers are now forced to address the market and especially the individual customer with augmented care by putting more emphasis on the service levels they provide, by reducing response times and by tackling the specific needs of the diversity of customers. This confluence of trends has led managers moving from a traditional functional focus in the way they conduct business into a more holistic approach in the manner they address the supply chain. As consequence, it is emerging at industrial level an adoption of collaborative strategies addressing the small series production of high-customized complex products with increased emphasis in the service levels and the reduction of the response times. Along this vein, consumer needs and expectations of specific target groups -such as elderly, obese, disabled, or diabetic persons -are arising as challenging opportunities for European companies which are asked to supply small series of innovative and fashionable goods of high quality, affordable price and eco-compatible in short periods of time and with high service levels. In order to design, develop, produce and distribute such products, a new framework and related components of collaborative networking are necessary.

The main objective of this research, framed within the EU (European Union) funded project CoReNet, is to present an innovative Reference Model for the TCF SMEs (small and medium enterprises) companies in collaborative networks to support the manufacturing of small batches of products addressing the need of the special consumer target groups. The aim of this new reference model is to equip fashionable and healthy footwear & garments network managers and stakeholders with the necessary guidance to model, design and configure the combination of processes, functions, activities, relationships and pathways along which products, services and information move in and between TCF companies.

The remaining of this paper is organized as follows: first the existing related literature is shown, followed by a presentation about multiple case studies conducted within footwear companies to single out and study distinctive practices and processes. Finally, based both on literature review and within and cross case analysis, a comparison between the distinctive practices and relevant processes in the TCF industry is presented in order to highlight the best practices and add new knowledge to the sector.

Foundations and Research Topics

In order to address the new type of target groups (elderly, obese, disabled, or diabetic persons) demand, it is necessary to develop new collaborative supply chain solutions based on cost effective, social compliant and eco-efficient design and production of customized products that fully satisfy the customers, considering their health issues as well as their desire for fashionable products.

Recent research in the field addressed different forms of business networks. The literature distinguishes for example by value chain orientation (horizontal, vertical, lateral), life span (long-term vs. short-term), and degree of virtualization or hierarchical structure (hierarchical vs. non-hierarchical networks) [START_REF] Camarinha-Matos | Collaborative Networks for a Sustainable World[END_REF]. Nevertheless, the most common business networks are formed along the value chain and for enduring purposes [START_REF] Christopher | Logistics and supply chain management -Creating Value-Adding Networks[END_REF].

At the same time, the current market trends calls for flexibility at the supply network level, the processes and the product designs in order to empower the companies to quickly adapt for new business requirements and sustainability challenges. This new demands are forcing business networks to have much shorter life-time existence and take advantage of new infrastructure technologies supported in distributed information systems and knowledge [START_REF] Simchi-Levi | Operations Rules -Delivering Customer Value through Flexible Operations[END_REF].

The new concept of demand-driven supply networks is emerging in literature as a collaborative approach in response to consumer's needs and expectations [START_REF] Childerhouse | Analysis and design of focused demand chains[END_REF][START_REF] De Treville | From supply chain to demand chain: the role of lead time reduction in improving demand chain performance[END_REF]. In reality, many companies that embrace this paradigm transformed their operating systems from the traditional functional supply networks through a holistic approach that addresses demand in all of its dimensions. This implies different approaches to the market based not only on traditional sales channels (shops, retailers) but more and more on an Internet mediated direct contact with consumers equally for product conception, for product sales but also for after-sales services.

Simultaneously, the market increasingly values collaborative networks that endorse the sustainability challenges. These networks by seeing the world's present and future challenges seek to develop new products and processes that can be part of the solution. Namely, through a holistic view of the supply network it is possible to measure and optimize the overall impact of the "carbon footprint", to implement policies that seek recycling and waste prevention, product design for sustainability and the use of emerging clean technologies [START_REF] Simchi-Levi | Operations Rules -Delivering Customer Value through Flexible Operations[END_REF]. From the production viewpoint, companies from different sectors in sustainable networks need to integrate their production systems in order to offer to the customer integrated solutions and innovative services and products.

A deep analysis of some of the most important supply network reference models present in literature -among others: Value reference model, SCOR model and Y-Cim model -have shown the applicability of the SMART model proposed by Filos and Banhan [9] as starting point for the definition of the Fashionable and Healthy Clothing & Footwear reference model for supply networks. The SMART model allows the definition of practices, technological and performance models for collaborative networks according to the following three main dimensions:

1. Knowledge dimension -to map partners' competencies to be shared within the network in terms of products and processes; 2. Information & Communication Technologies (ICTs) dimension -to support the requirements for the implementation of ICT services at different process levels along the network;

3. Organizational dimension-to provide specifications of the organizational changes for SMEs for structuring supply networks in small series production.

In order to make the reference model for the TCF European companies cope with the environmental consciousness, the present reference model approach used the SMART model proposed by Filos and Banhan [9] and additional presented a new dimension, coherent with eco-efficiency objective, the Sustainability dimension. This new dimension is intended to support the enterprises in the developing of an ecocompatible approach for their products and processes.

A set of companies belonging to the TCF sector has been selected to conduct multiple case studies to investigate this new research field, within textile, clothing and footwear companies in order to identify and investigate distinctive practices and processes suitable for characterising the Reference Model proposal. The sample was selected adopting theoretical sampling [START_REF] Glaser | Grounded Theroy: the discovery of grounded theory[END_REF], and multiple investigators are used to reduce bias and create more reliable data [START_REF] Eisenhardt | Building theories from case study research[END_REF][START_REF] Pagell | Understanding the factors that enable and inhibit the integration of operations, purchasing and logistics[END_REF].

An "as is" business process analysis was conducted through focused interviews and BPMN (Business Process Modelling Notation) representation to collect and formalize a rich set of data, both qualitative and quantitative. Furthermore, the requirements of each company were pointed out and analysed in detail to draw the relevant characteristics, procedures and techniques along their supply constellation.

Within-case analyses allowed the study of each individual company singularly and understand their requirements in terms of the four dimensions, while a cross-case analysis among the different companies allowed the comparison of the companies' behaviour and understand their collaboration mechanisms.

Reference Model for TCFI Collaborative Networks

The research project CoReNet (Customer-Oriented and Eco-friendly Networks for Health Fashionable Goods) [START_REF] Fornasiero | Research issues Customeroriented and eco-friendly networks for health fashionable goods[END_REF][START_REF] Azevedo | Customer-Oriented and Eco-friendly Networks for Health Fashionable Goods -The CoReNet Approach[END_REF], intends to support textile, clothing and footwear companies in the implementation of new models for small series production for health and fashionable goods. Furthermore it follows the Competitive Sustainable Manufacturing (CSM) paradigm [START_REF]FoF-PPP: Factories of the Future: Public, Private Partnership, Strategic Roadmap[END_REF] and current initiatives of European Technological Platforms like Manufuture [START_REF] Manufuture | Strategic Research Agenda[END_REF] and Footwear. The project intends to support the whole value chain to get and manage consumer data to investigate its needs; involve consumer into design and product configuration phases; exchange consumer data through adequate data models and secure systems; manage the collaboration with suppliers in order to plan and distribute on time; implement innovative manufacturing technologies; deliver timely the product to customer; and monitor the quality and sustainability of products. This approach aimed to develop a systematic strategy for the supply network configuration, coupled with a detailed definition and characterization of the operative level of processes and activities along four main dimensions (Knowledge, ICT, Organizational and Sustainability).

The Reference Model enhances the TCF companies in addressing specific target groups by enabling them in producing healthy and fashionable products in a collaborative environment. The base ground for the model was based in a comprehensive literature review and case-analysis field work. As depicted in Fig. 1 diagram the Reference Model will support TCF companies at strategic level covering the overall collaboration framework of the supply chain, at tactical level with the support to the definition of the processes which emerged as relevant for this kind of business and at the operational decision level by presenting rules and "best practices" to align the material flow to the specific market needs. In the following sections it will be detailed these three levels.

Strategic Level

Regarding the strategic level, the business model framework proposed by Osterwalder [START_REF] Osterwalder | Business Model Generation -A Handbook for Visionaries, Game Changers, and Challengers[END_REF] was applied as conceptual approach. The model maps the most important building blocks that influence the definition of the value proposition. The idea is to instantiate the model to the specific case of TCF sector. Osterwalder [START_REF] Osterwalder | The Business Model Ontology -A Proposition in a Design Science Approach[END_REF] widens this concept and defines Business Models as: "…a conceptual tool that contains a set of elements and their relationships and allows a company's logic of earning money. It is a description of the value a company offers to one or several segments of customers and the architecture of the firm and its network of partners for creating marketing and delivering this value and relationship capital, in order to generate profitable and sustainable revenue streams".

In this regard, it is understood that business models should not only comprise the perspective inside organizations, but also embrace a wider perspective that includes potential partnerships, customers' requirements, revenue shares and other elements. A graphical representation merging the models presented by Ostervalder and (improved by) Romero et al. [START_REF] Romero | Towards The Definition Of Business Models And Governance Rules For Virtual Breeding Environments Network-Centric Collaboration and Supporting Frameworks[END_REF], as well as the empirical-based marketing approaches developed by Plantin [START_REF] Plantin | Orange Labs R&D internal methodology for building business models[END_REF] is shown in Figure 2. It is important to mention that this amalgamated representation is in accordance with Chesbrough and Rosenbloom [START_REF] Chesbrough | The role of the business model in capturing value from innovation: evidence from Xerox Corporation's technology spin-off companies[END_REF] proposition, where a business model is placed as a linking ingredient between technical inputs (infrastructure management) and economical outputs (customer interface and financial aspects).

Fig. 2. chain strategy based on building blocks

In collaborative endeavours, and therefore co-creation environments, value propositions are common ground between collaborative-networked organizations and customer communities. Collaborative networks should combine the capabilities of their members to create new abilities to better support the personalization of experiences and with customer knowledge synergies co-create real personal value propositions where the consumer is starting to play an increasingly important role in the co-construction of value offers [START_REF] Romero | Collaborative networked organisations and customer communities: value co-creation and co-innovation in the networking era[END_REF].

Following this perspective, Table 1 depicts the most important features of the building blocks for the business model of healthy and fashionable SMEs. In addition the dimensions involved in each building block are identified. The most important characteristics that differentiate healthy and fashionable SMEs from the traditional footwear companies is the direct contact via web with final customers, that gives to small and medium manufacturers the possibility to understand customers needs without intermediaries and easily create best-fit configurations to fulfil their requirements. In order to allow firms to achieve this result it is fundamental to implement the right infrastructures in the companies, basing on the four dimensions of the Reference Model. In particular: knowledge on the requirements of target groups, ICT infrastructure to support the whole business model, organizational aspects to manage the supply network and sustainability to guarantee competitive advantages along the time.

Tactical Level

From the case-studies analyses a set of critical processes emerged as important to satisfy collaboration business requirements at network level. These processes have been mapped and formalized in a BPMN (Business Process Model Notation) representation [START_REF] Fornasiero | Research issues Customeroriented and eco-friendly networks for health fashionable goods[END_REF] as presented in figure 3.

The overall tactical level of the model is based on a customer-oriented approach to the supply network configuration. The starting point of the overall process is twofold according to the level of customization/configuration it is decided for the Target groups. On one side, the processes IM1 and IM2 represent the starting point from the customer. Traditional shopping as well as online configurators and customer profiling for specific customer groups are taken into consideration. IM1 and IM2 allow direct customer interaction on footwear, textiles or clothing products with special features for the consumer target groups (elderly, obese, diabetics and disabled people) with the possibility of product configuration and full visualization of products characteristics. From IM1 and IM2 it is possible to go to CD3. On the other side, Co-design with Knowledge Management Tools (CD1) supports the identification of market needs and consumer preferences for new products and functionalities in CD2. Another important process is the Definition of Product Collection (CD2) for specific target groups based on collaborative environment where different type of users (internal and external to the company) with different roles can contribute to define a collection of suitable products for the target consumers. Regarding the small series production, it has been defined the Product Design process with CAD modelling (CD3) which is carried out by the (internal and external) designer and outcomes the CAD technical model of the product. Also includes selection of materials for both clothing and footwear.

Process planning (CD4) is related to product engineering and has the aim to decide how to manufacture the product and to generate all related information. In this phase suppliers and outsourcers are identified and defined and the costs for the different manufacturing phases are determined. Also the BOM, the working cycles and the production times of the new product model are also defined.

Customer order processing support (CP1) is based on automatic pre-processing of customer orders for administrative and pre-production checks and issues. The final output is the list of customer orders ready to be processed for production. With collaborative process planning (CP2) all standard and default data can be uploaded to the early (automatic) set of Production Orders; external activities (to be outsourced) require the identification of potential partners to be assigned. The output is the set of production orders ready to be scheduled. In Collaborative production planning and control (CP3) production orders related to the same customer's orders can be scheduled using a collaborative tool where manufacturer and partners inside the collaborative network can share a view of the production order schedules and close a "negotiation" for the definitive launch of manufacturing activities.

Last, the cross-cutting process of partner monitoring and trace support aims to monitor production orders as well as KPI related to Quality and Sustainability. The outcome includes overall status, alerts/warnings and high-level KPIs. For each of these processes a detailed description has been developed including information related to the flow of activities and related to the four dimensions of the model.

Operational Level

Regarding the Operational Level it has been identified a set of practices that define the relationships between the tactical level and the four main dimensions and establish guidelines for the operational level decision making. An excerpt of the vast list of these Reference Model rules and operational best practices is presented in Table 2.

Tab. 2. Excerpt of Operational Level table

SALES/CONFIGURATION PROCESS

Conclusions and Further Research

The ongoing European project "Customer-oriented and eco-friendly networks for healthy fashionable goods (CoReNet)" aims to provide TCFI companies with the tools and methods to face the challenge of working in demand-driven and customer oriented collaborative networks. Until now the project research work allowed the definition of a Reference Model that set up the foundations for the development of future technologies and tools that support network operation. The following phases include the instantiation to specific companies' requirements of the reference model according to their business model in order to support them in the path to small series production of healthy products. The model is currently under evaluation and improvement in the CoReNet project together with the industry partners and the customers. The final goal is to provide a sound customer-oriented reference model suitable to collaborative network managers and stakeholders of TCF industry.

Acknowledgments:

The research leading to these results has received funding from the European Union's Seventh Framework Programme (FP7/2007-2013) under grant agreement n° [260169]. ORGANIZATIONAL a customer driven supply chain, end-user demand drives all activities among trading partners according to culture that puts the customer first.

Some steps realized by downstream supply chain actors can be reduced compared to direct sales.

SUSTAINABILITY

Commitment with the customer to give information on sustainability.

Formalized knowledge of information needed for the customer to assess the sustainability of the products.

Fig. 1 .

 1 Fig. 1. Reference Model Context Diagram

Tab. 1 .

 1 Building blocks for traditional SME and healthy and fashionable SME fit sessions to define and adjust configuration space (of variants) according target groups' needs Knowledge -Organizational Direct electronic communication to endconsumer using internet interface and feedback Capabilities Market analysis based on Data from Knowledge Management Tools (KMT) supporting the definition of the configuration space

Fig. 3 .

 3 Fig. 3. BPMN representation of the mapped processes

BUSINESS REQUIREMENTS IM1 -Traditional shopping support for specific customer groups IM2 -Online visualization, configuration and acquisition of leather/footwear KNOWLEDGE

		DESIGN PROCESS
	BUSINESS REQUIREMENTS	CD1 -Co-design with Knowledge Management Tools support	CD2 -Definition of Collection Support	CD3 -Product Design with CAD modeling support	CD4 -Process planning support
		Need of data sharing
		agreements between			New solutions in
		retailers, manufacturers and	Knowledge on the		terms of new process
	KNOWLEDGE	designers but also the involvement of consumers	specific functional requirements of the	Postponement, Product innovation,	plans, as well as reduces the time
		through specific online	customers.	Open innovation	needed to reach
		communities of consumer			satisfactory solutions.
		target groups.
	ICT	…	…	…	…
		PRODUCTION PLANNING PROCESS
	BUSINESS REQUIREMENTS	CP1 -Customer order processing support	CP2 -Support for collaborative process planning	CP3 -Support for collaborative and control production planning	CP4 -Partner monitoring and trace support
	KNOWLEDGE	(a) The analysis and translation of the product configuration information into the production article data in terms of materials and production processes (for lot size 1, and for small series). (b) Aggregation of orders. (c) Partner selection in order to collaborate with them.	Information already stored in the PDM system and related to generic BOM and working cycles for product models. Order specific information that will integrate these will have to be coherently structured according to a common framework.	Impact of the right or wrong production on the pathologies.	Ability to include in the definition of KPIs proper inputs from final customers requirements and needs, especially the ones belonging to the target groups addressed by the project as, for example in terms of anallergic and no toxic materials.
	ICT	…	…	…	…
		Customer involvement. Customer requirements	Formalized knowledge of information needed
		management. Clinical aspect and functional	for the customer to assess the performance of
		requirements.	the product.
		Availability of machines like scanners, cameras, virtual	It is necessary to create a clear and single access
	ICT	mirrors, etc.. able to get images, 3D rendering of	point that customers can recognize as online
		feet\bodies for product design.		shop.


Kai Mertins
email: kai.mertins@ipk.fraunhofer.de

Thomas Knothe
email: thomas.knothe@ipk.fraunhofer.de

Pavel Gocev
email: pavel.gocev@ipk.fraunhofer.de

Towards CPS Based Aircraft MRO

Keywords: Cyber Physical Systems for MRO, modelling and simulation, MRO Planning and Control

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

Introduction

Availability and reliability of aircrafts are essential factors in the global competition of the airlines. Beside the operative execution of Maintenance, Repair and Overhaul (MRO) the planning and control of the MRO processes impacts the aircraft availability too. This emerges directly from the configuration complexities of IT-Systems, variety of tools and spare parts as well as numerous locations with their qualified specialists. At present the planning and control processes are carried out sequentially including unnecessary loops, redundancies and interfaces using different media and various structures from the MRO demand until the aircraft serviceable. The complexity is even higher due to the mixture of the planned and unforeseen MRO work. The improvement potential is estimated on 1 to 3% of availability increase yielding an amount of two-digit EUR Millions per mid-sized airline.

There is a necessity for a novel solution that will eliminate current problems emerging from the above described situation:

• Changes of flight plans or unforeseen technical problems extend the Aircraft on Ground (AOG) time due to unavailable MRO-Resources.

• MRO-Process landscape causes long through put time on operational and administrative level.

• Diagnosis systems do not consider the all necessary and available data for prediction of possible malfunctions and failures.

• Large C-and D-Checks are carried out as separate projects, but not broken into small work packages (Single Running Tasks) that can be executed during the daily checks of the aircrafts.

• The response data and information from the MRO-Processes are not promptly used by the suppliers, either for design and development of components, nor for the modernisation and further improvement.

In order to answer on these challenges in this paper a solution is proposed based on deployment of Cyber Physical Systems (CPS) for context-sensitive planning, control and realisation of aircraft MRO-Processes. CPS is defined by Broy (1) as a narrow connection of embedded systems with the global digital networks with the goal of monitoring and control of physical occurrences using sensors and actuators as well as communication equipment. The goal of the below described solution concept is to reduce the complexity in the execution of MRO-Processes and to shorten administrative process parts. The aircrafts will carry CPS-Components that will be networked in one Platform and will be able to take decisions based on the particular situation. Therewith the aircrafts will issue an MRO-Order directly to the MRO-Operation under consideration of the available time, resources and spare parts. The solution will generate Single Running Task for MRO that will be released in a flexible way reducing the through put time and AOG time, increasing the availability of the aircrafts. The paper will give an overview of the challenges and will describe the concept for a solution as well as the necessary steps towards the solution realisation in this complex environment.

Industrial Challenges, Requirements and Needs

The improvement potential as mentioned in chapter 1 is currently limited by the complexity of planning and control of frequent as well as unscheduled MRO events for different stations in accordance to the individual work demand for each aircraft. Cost intensive spare parts, specific tools and equipment as well as special qualified personal are only available in selected stations. For unforeseen events expensive maintenance flights are required or deletions have to be taken. In order to prevent flight deletions reserve aircrafts have to been foreseen. As consequence the utilization of the entire fleet will be reducing. Unsatisfied customers and additional effort for aircraft operations are additional consequences. TOP Level Business Requirements for Aircraft MRO-Provider:

• Realization of direct and consequently free of loop processes for maintenance planning and control. This would reduce the current process duration drastically.

• Improvement of reactivity of the MRO-provider regarding sudden required maintenance and repair activities. It has to be implemented that mechanic-resources, spare parts, tools at locations will be provided in accordance to flight-plan, diagnostic data by optimal use of maintenance slots.

• Optimize the implementation of the concept of "Single Running Tasks". This means, that a small maintenance step of complex C-and D-Checks can be applied during regularly daily line checks and enable the reduction of the normally long duration of these C-and D-Checks. Currently this improvement cannot be applied, because of the complexity of planning and control procedures.

• Correct estimation of "out of order" cases and integration into the maintenance planning and control. Through this the number of sudden cases will be reduced, which cannot be planned in beforehand. The time of "Aircraft on Ground" has to be reduced and the availability improved.

• For Aircraft and Aircraft Equipment Provider:

• A fast feedback of specific flight and maintenance data for improved support of aircraft modernisation, which is performed sometimes annually. This leads to enhanced agility and customer orientation.

• Direct data integration of maintenance related feedback from aircraft operations and maintenance into the IT-Systems for aircraft development and modernisation.

Similar requirements and needs are relevant in other industries like rail.

State of the Art

The demand on solution can be deducted from the viewpoint of the MRO-Service provider and from aircraft producers. Usually the process of MRO planning and control in air traffic is supported by specific IT-Applications as TRAX, or similar (2). These systems consider diagnosis data as well as operative aircraft information. Typical for these solutions is a redundancy of acquisition of data and information, data management. Moreover there are information gaps along the information process chain that impact the realization of the process in negative manner. Furthermore the long planning chain from MRO demand to the MRO operation by the mechanic requires too much time and implies a lot of inefficient loops (Fig. 1). Related to the planning and control Sampigethaya (3) describes on a conceptual level the functionality of a direct communication between aircrafts and one Cyber Physical System (CPS). Thereby a focus is put on security of networks and communication infrastructures and a distributed planning and control as well as integration of CPS in the MRO-Processes is not mentioned at all. The interface between the diagnosis and the predicted MRO is considered by Lee (4) already for more than 10 years but the suggested solution cannot answer on the challenges to cope with the specific dependencies within the MRO in the context of complex circumstances as for example the holistic air traffic systems.

The air craft producer Boeing developed in the last years the so called "Boeing e-Enabled Solution" on a base of a reference architecture which should enable a strategic connection and integration of business processes, human resources, aircrafts, information and knowledge. The optimized and transformed processes through direct Ordering of Mechanic personnel and their response for the accomplished work are not foreseen with this solution and therewith there is no simplification of the MRO planning and control processes. For the feedback aim between MRO and the producer there are various additional systems which besides the partial data integration are dependent on manual efforts (4).

In the domain of services exist also reference models [START_REF] Fettke | Business Process Reference Models: Survey and Classification[END_REF], like those which facilitate simulation of planning and control processes for MRO [START_REF] Knothe | Referenzmodell Auftragsdurchlauf für Dienstleistung und Verwaltung[END_REF]. The specific situation and the complexity of aircraft maintenance is only limited considered in the models. Methods for handling the complexity in integrated models are not inside these reference models. A suitable method would be a contextual integration of product and process models [START_REF] Girod | Integrierte Produkt-und Prozessmodellierung[END_REF]. The market is also supported by Integrated Product-Service Systems (IPS Systems) through contracting and material ordering up to response on carried out MRO work [START_REF] Macinnes | Strategic MRO-A Roadmap for Transforming Assets into Competitive Advantages[END_REF]. In this case the MRO orders and responses need manual inputs of the MRO order progress status. IPS-Systems generate MRO-plans on the base of the available information and under deployment of rigid and predefined rules. These rules are usually operational charts, procedural conditions and are not flexible and not context sensitive. Routings are usually created manually and can be hardly adapted to the emerging situation. All these constrains and restrains the overall agility of the realization of MRO processes. The results from the research project SoPro (10; 11) is worth to contribute to the intelligent planning and control of MRO activities through self-organized production. In the SoPro project small computational unit eGrains have been developed which can be assembled on the MRO assets, transportation means, processing resources, tools and fixtures and that are equipped with agent based software and radio communication. Therewith through combination of negotiation of the agents the best optimal routing can be suggested and carried out, so a technical foundation for support of MRO processes is given. The German national project ARAMiS ( 12) is developing a concept for multiprocessors which offer new functionalities in the air traffic. Although there is no direct relation between to MRO, these processors can be utilized into CPS due to their efficiency and stability in order to enable direct assignment of the mechanical personnel by the system. In general, the technological base for CPS extended aircraft avionic and MRO processes is available but there are numerous constraints which have to be adopted, integrated in the practical MRO environment. The mechanisms for system-integrated assignment, calculation, planning and control of MRO orders are still in an early phase and not applicable yet. The conditions for overall and comprehensive deployment of integrated MRO systems are still not available. The feedback from the MRO domain to the product design with the purpose of product improvement occurs at present only when corrective action and measures have to be taken or based on statistic evaluation. A direct context-sensitive feedback to the suppliers does not exist and therewith the improvement of processes and products are cost and effortintensive.

Solution Concept

The above described challenges were addressed by Fraunhofer IPK considering an aircraft MRO-process chain form aircraft component supplier, aircraft OEM up to airline and MRO service provider. The solution is related to a context-sensitive planning, control and realization of aircraft MRO-Processes based on deployment of Cyber Physical Systems (CPS) with the goal to reduce the complexity in the execution of MRO-Processes and to shorten the administrative part. The aircrafts and their components will carry CPS-Components that will be networked in one solution platform and will be able to take decisions based on the particular situation, and consequently will issue an MRO-Order directly to the MRO-Operation under consideration of the available time, resources and spare parts. The solution will generate Single Running Task for MRO that will be released in a flexible way reducing the through put time and Aircraft-on-Ground (AOG) time, increasing the availability of the aircrafts. The goal is to deploy and utilize the solution of Cyber-Physical Systems within the MRO-processes. Moreover the depending processes like product design, production planning and control, as well as ergonomics will be considered. Due to the complexity of the whole concept, the solution will be developed on the basis of one or more use cases that will prepare the challenges and requirements for a solution from the industrial and business point of view. This will support the formal description of the necessary objects within the MRO domain, as well as their transformations along the MRO-Processes. In particularly the specifics of processes, resources, technologies, products and practices of MRO will be considered and their nature and features will be analyzed. The relations and dependencies between the objects (aircrafts, components and MRO-resources) within the MRO-processes will be described in one extended process model that will keep all relevant aspects and the respective interdependencies. The solution will utilize the definition and description of the MRO-processes and activities that have to be performed to each aircraft component according to the defined plan or checks. This will include a list of activities to be carried out and necessary resources for each activity. The challenge is to cope with the real situation at the airlines. On one side the aircrafts are changing their geographical position with the time and on the other side the MRO-resources are spatially scattered in more locations. As not every MRO-location offers every MRO-service the solution will offer an execution of the MRO-processes (checks) in one optimal way. The aircrafts and their components that are a subject of MRO will be integrated into the MROplanning and control system in the way that they can be pro-active and react on the environment. This will be enabled through equipment the aircraft components with CPS-objects like sensors, actuators, RFID, respectively "small computers" that are able not only to read and write data and information but to process them and proactively to cooperate in one CPS based MRO system. In that way each aircraft component will carry with itself the information about the MRO-demand and necessary MRO-processes to be carried out. Moreover the aircraft component will be "aware" about the required MRO-resources that will be capable to perform the MRO-process. In regard to the current location of the aircraft and considering the flight plan each aircraft or component can match the MRO-process to be realized with the available resources at the same location. Matching the all criteria relevant for performing the MRO-process the aircraft or the component will be able to take a decision, to select a single running task to be realized, to generate a MRO-order for selected MRO-resource and to assign the MRO-work to the resources. All that will happen locally via direct communication between the aircraft or its component and the MRO-location and its resources. The personnel responsible for accomplishing the MRO-work will get the work instruction and all necessary information including the history values about the aircraft or component directly from the CPS-object carried by the aircraft or component. In a similar way the realized MRO-work and the findings as well as the performed changes and the information about the built spare parts can be sent to the CPS-object directly to the aircraft or component and therewith the history values will be updated in a very direct way of communication between the execution participant of the MRO-work and the aircraft or component that experienced the MRO-process.

The impact of the proposed solution can be multiple regarding the better performance of the MRO-Processes, improved utilization and sustainability of the systems, bringing together various information sources for better planning and control. Moreover this will foster the further development of the CPS-components and open the perspectives for new applications of CPS in other domains. One example is the railway sector with similar business conditions to synchronize overnight short maintenance, regular long lasting maintenance projects, timetable oriented operation and many maintenance locations as well as expensive equipment and parts. The new paradigm will drive the R&D community for new solutions that will improve the efficiency of the systems and will enable an accomplishment of complex challenges with the final goal of improvement of the economic well-being.

Outlook and Further Steps

Besides the opportunities of the described concept, the longterm aircraft product live cycle will be a barrier of the implementation of CPS based aircraft and CPS based aircraft maintenance. Nevertheless there are two midterm steps to go on the modernization way:

• Start with the implementation according to software updates for the aircraft avionic, because the infrastructure (e.g. wireless LAN on airports) and the technology (e.g. Boeing avionic) is currently available.

• Enhance the flight bag system (tablet PC for pilots, contain routes, maps and calculators, e.g. for fuel consumption estimation) with reading interface to aircraft data bus system. A communication system to the maintenance planning and control integrated on the flight bag system can support the direct processes from aircraft to maintenance staff. The improvement of the flight bag system is independent from aircraft design changes; the interface to the aircraft data bus already exists.

• Implement auto-id systems for expensive parts and tool as well as insure the data integration into maintenance planning and control system.

The solution approach affects a number of standards, especially aircraft architecture like ATA42 chapter "Aviation Industry Standards for Digital Information Security", MRO-Standards, regarding MRO-operations from EASA, Part-145, Part-66, Part-M. In the near future these standards need to be checked and if necessary revised in order to allow CPS based aircraft maintenance. E.g. the part-145 is currently very much element oriented and on a status like ISO 9001 was in 1994. Here a process orientation is required, because the interaction of most of the elements of part-145 (e.g. staff qualification and repair procedure) have to be defined and implemented in their process context.

Fig. 1 :

 1 Fig. 1: AS-IS Process of Aircraft Maintenance Planning and Control

Fig. 2 .

 2 Fig. 2. TO-BE Concept of direct task assignment from Aircraft to mechanic, tools and parts

Order Assignment from AC to Mechanic Feedback from Mechanic synchronised with Avionic System

		Observation-
		Alert Management
		Capacity Planning
		Service Management
		Reliability Management
	Aircraft, CPS extended
	Tools / Parts, CPS extended
	CPS erweitert	CPS -Cyber Physical System

Mechanic with mobile IT-Infrastructure To Be Concept Automated commissioning and provision of tools and spare parts


Keith Phalp

Frank Grimm

Lai Xu

Supporting Collaborative Work by Preserving Model Meaning When Merging Graphical Models

Keywords: UML class models/diagrams, model merging, diagram merging model-driven, distributed, software engineering

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

Introduction: The Need for Merging Models within Collaborative Development

This paper presents a novel approach to model merging [START_REF] Westfechtel | Structure-oriented merging of revisions of software documents[END_REF] which is intended to bring gains to those working on collaborative software development. Whilst, in our case the primary objects (in the wider rather than software sense) are UML models, the lessons learned here have implications for collaboration more widely, where any shared artefact may be developed in a similar collaborative manner (based on diagrammatic modelling notations). The rest of the paper is organised as follows: section two gives background to model merging and the industrial context, section three outlines our findings on the importance of layout and section four then discusses the need for a different approach to merging. Section five discusses our 'semi-automatic' approach to merging and finally section six offers some conclusions.

Model Merging and Context

The context for this study was the production of software for automatic gearbox controllers, using a model driven approach [START_REF] Hermsen | Application of the object-oriented modeling concept OMOS for signal conditioning of vehicle control units[END_REF][START_REF] Schweizer | Development of product families -an example from the automobile industry[END_REF]. Hence, modifying, the software was achieved by first modifying the model, then the respective implementation (source code) modifications followed automatically [START_REF] Kleppe | MDA Explained: The Model Driven Architecture: Practice and Promise[END_REF]. Modifications could only be carried out in a sequential manner: before starting to work on the model and realise their modifications, developers at one site had to wait for the developers at the other site to finish their modifications, which was clearly an inefficient form of collaboration [START_REF] Harrison | Coordinating concurrent development[END_REF]. Hence, the main motivation for the research presented here was to remove the limitation of only one user modifying a model at the same time [START_REF] Mens | A state-of-the-art survey on software merging[END_REF] and to enable a genuinely collaborative approach. However, when evolved models are modified independently from each other, the same model elements might have been modified in different and potentially contradicting ways [START_REF] Conradi | Version models for software configuration management[END_REF]. These 'merge conflicts' usually cannot be solved automatically by a merge tool, since such a tool cannot decide which element version to use in the merged model [START_REF] Conradi | Version models for software configuration management[END_REF]. Hence, modellers (in our case software engineers) have to manually resolve conflicts and reason about conflicting changes [START_REF] Ohst | Difference tools for analysis and design documents[END_REF][START_REF] Kelter | A generic difference algorithm for uml models[END_REF]. It is important to re-iterate that, for model-driven software development, models are not just a means of visualisation and communication since source code can be derived automatically. Hence, the need to understand how modellers interpret the models, so that we could understand fully the impact of merging, as this will directly impact the resultant software artefacts.

The Importance of Layout

Initial results of this analysis are presented in [START_REF] Grimm | Enabling multi-stakeholder cooperative modelling in automotive software development and implications for model driven software development[END_REF]; the results having come from examination of two substantial projects [START_REF] Grimm | Enabling collaborative modelling for a multi-site model-driven software development approach for electronic control units[END_REF]. The following lists some of the ways in which we found that the software developers used layout to convey meaning (in our case for class diagrams). Notably, this, often domain-specific meaning, is neither formally defined in the model nor the diagram itself. The interested reader is referred to Grimm [START_REF] Grimm | Enabling collaborative modelling for a multi-site model-driven software development approach for electronic control units[END_REF] for an exhaustive list.

• The absolute position of a class symbol was meaningless [START_REF] Eichelberger | Aesthetics of class diagrams[END_REF][START_REF] Eichelberger | On class diagrams, crossings and metrics[END_REF], though the symbol's proximity (diagram context) and relation the other class symbols was important for the modellers' mental-map [START_REF] Misue | Layout adjustment and the mental map[END_REF] of a diagram. • Class symbols did not overlap (a fundamental requirement of readability) [START_REF] Tamassia | Automatic graph drawing and readability of diagrams[END_REF], were often ordered according to their semantics in the software design domain, and UML class diagram layout guidelines often [START_REF]UML Notation Guide[END_REF] ignored. Symbols of closely related classes were then positioned in close proximity to each other; for instance in containment (whole-part) and inheritance hierarchies [START_REF] Petre | Why looking isn't always seeing: readership skills and graphical programming[END_REF]. • Diagrams dealing with similar domain concepts, i.e., representing classes whose semantics were closely related, often exposed a similar layout structure, supporting the finding that diagram layout conveys inherent information important to modellers.

• Elements placement was based on modellers' knowledge of semantic relationships among elements and how they wanted to represent this knowledge in a diagram. For instance, sometimes two subclasses were placed on the left hand side close together, while another subclass on the same inheritance level was placed on the right apart from its semantically related variants. This concurs with Petre [START_REF] Petre | Why looking isn't always seeing: readership skills and graphical programming[END_REF] who found that placing unrelated elements close to each other led to the misinterpretation that they were semantically related. • The position of class symbols was more important than being able to draw connection as straight lines. So, positioning class symbols in their semantic context overweighted the connections the class had to other classes in the respective diagram [START_REF] Eichelberger | Nice class diagrams admit good design?[END_REF]. However, there was no preferred direction of connections; though if a diagram depicted classes in a clear hierarchical context, then a top-down direction of connections was preferred [START_REF] Purchase | Evaluating graph drawing aesthetics: defining and exploring a new empirical research area[END_REF]. Moody [START_REF] Moody | The "physics" of notations: a scientific approach to designing visual notations in software engineering[END_REF] argues that the layout guidelines given by the UML standard [START_REF]UML Notation Guide[END_REF] are flawed in several ways, and, as the results of our diagram analysis show, those guidelines were not followed rigorously. Hence, diagram layouts can, and do, differ and are subject to the interpretation of the modellers who create or modify them.

The main generic finding is that the layout that modellers choose for a diagram is intentional and follows informal, unspecified rules. Elements (mainly class symbols) were placed in accordance with the element's semantic (i.e., domain) meaning and the engineer's understanding of this meaning. Hence, elements that are closely related in terms of their domain semantics are likely to be positioned close together in a digram as well. Thus, adjacent diagram symbols usually reflect a close relationship of the semantic concepts and their layout in the diagram conveys this meaning visually .

Implications: A Different Approach to Merging

It was clear from our study that layout heuristics were being used in the construction of models and allocation of classes to models. These findings strengthened the conviction that merging was vital, but needed to take account of, or at least try to preserve, as much of the meaning that layout conveyed as possible.

However, having conducted a thorough analysis of existing automatic diagram layout approaches (typically based on automatic graph layout algorithms) it became clear that these did not meet our needs because they merely preserved the connections (in a topological sense) rather than dealing with the layout itself, and, similarly ignored many of the heuristics suggested above [START_REF] Eichelberger | Aesthetics of class diagrams[END_REF].

In addition, for UML, automatic layout algorithms are based on UML model elements, i.e., the semantic elements like packages, classes, and inheritance and association relations among classes [START_REF] Eiglsperger | Automatic layout of UML class diagrams in orthogonal style[END_REF]. Since automatic layout algorithms focus on creating aesthetically pleasing layouts, they try to optimise diagram layouts with respect to edge crossings and bends [START_REF] Eichelberger | On class diagrams, crossings and metrics[END_REF], but they do not take the mental map of a diagram into account. When symbols are added to or deleted from a diagram, an automatic layout approach might create a completely different layout. Hence, users working with the diagram would have to re-learn the diagram.

Given those issues related to conventional layout algorithms, the challenge was how to enable efficient model and diagram merging whilst still allowing modellers to preserve the domain-specific information. Ideally, a diagram merge approach would automatically merge diagrams in a meaningful way and burden users only with solving "real" diagram merge conflicts. The ideal scenario would be to allow modellers to create diagrams the way they want with all possible layout freedom, but still be able to rely on mental-map-preserving automatic layout. These two objectives of course contradict each other -layout freedom and automatic layout cannot be combined without one limiting the other.

The authors suggest that a certain degree of automatic layout is desirable, for creating diagrams in the first place and for merging them. When model elements depicted by diagram symbols are updated, a modelling tool has two possibilities, (1) update the diagram symbols' graphical properties (including its size) or (2) leave them as they are and let the modellers take care of manually updating the diagrams. Given the above drawbacks of fully automatic diagram layout, but also given that automatic layout is useful to some extent, and given that merging fully manual diagram layout in a meaningful way is not possible, a semi-automatic layout is described briefly in the following section.

Implementing a Merging Tool

Since a diagram can be independently modified by different modellers, in parallel, the diagrams should ideally be combined without user interaction if there are no diagram merge conflicts (and the resulting diagram layout should still be meaningful). Therefore, a semi-automatic layout approach is presented which allows modellers to make the grouping and ordering of class symbols explicit.

As discussed above, these two layout features were found to be most important with respect to defining and conveying domain-specific meaning; thus, when modellers create diagrams, they can explicitly define the order of class symbols. In our approach this is the only layout information that can be defined manually. The more layout features modellers can influence, the more diagram merge conflicts can occur because the features were conflictingly changed in parallel in both evolved diagrams. Those conflicts then have to be resolved manually. This additional diagram information is then taken into account when class diagrams are laid out automatically. The extra information is leveraged in order to position class symbols according to the manually defined order. Thus, for example, modellers are able to explicitly define the principal horizontal and vertical ordering of class symbolswhich are then automatically laid out as trees in a top-down manner. Being able to automatically re-arrange diagram symbols during the diagram merge process relieves modellers from having to deal with unimportant layout merge conflicts (e. g., symbol overlapping) and allows them to automatically create uncluttered diagrams during the merge. A brief description of our algorithm now follows (again see Grimm [START_REF] Grimm | Enabling collaborative modelling for a multi-site model-driven software development approach for electronic control units[END_REF] for a more detailed treatment). As a first step, the changes between both evolved models and the common ancestor are calculated by comparing the states of equivalent model elements. Equivalent elements in different model versions are determined by means of globally unique identifiers and it is then decided, for each change, whether or not it can be accepted. Conflicting changes are rejected. For model elements with conflicting containments this means that the model element is not part of the initially merged model. Then, so-called existence conflicts exist, and the modeller has to manually decide which parent element contains the element. If an element is not included in the initial merged model, its children elements are also omitted. Referencing any such element from other elements is not possible. Thus, such references are also marked with merge conflicts. As a second step, the actual merged model is created. Any model element which does not have an existence conflict becomes part of the merged model. Of course, these model elements might have merge conflicts, too. However, these conflicts do not prevent the element from becoming part of the merged model, though they would need to be resolved manually by the modeller. The merge tooling also provided modellers with the possibility to resolve merge conflicts by accepting and rejecting model and diagram changes. Not only could modellers modify the merged model (diagram) by means of accepting or rejecting changes, but also they could also modify it in any way. Therefore, even model elements or symbols which were not changed at all (not even non-conflictingly) could be modified. Hence, the editing capabilities of the implemented model merge tool were those specific ones required for dealing with changes, in addition to the common editing functions provided by an ordinary modelling tool and used when models and diagrams are created in the first place. The dedicated merge tooling took care of updating the acceptance status of changes when the merged model or diagram was updated -so that modellers could learn whether a change made in one model (diagram) was (still) part of the merged model.

In contrast to other automatic UML class diagram layout approaches, no layout heuristics or iterative layout were applied for the implemented layout approach. Such approaches are used to create more aesthetically pleasing and potentially more readable diagram layouts, but they have the drawback that the resulting layout might 'look' different every time a diagram is laid out and when the model is updated (and thus the information used to calculate the layout changed). Hence, the semi-automatic layout approach implemented here is a trade-off between diagram mergablity and manually creating UML class diagrams with all the freedom with respect to positioning / laying out of diagram symbols.

Hence, in our approach, the 'freedom' of manual layout was reduced in favour of being able to efficiently merge class diagrams, while the most important layout features (regarding embedding domain-specific information into the layouts of class diagrams) can still be defined manually by modellers. That is, the layout approach implemented here has as a priority keeping a stable and predictable layout. This means that the order of class symbols is not altered so long as the modeller does not change it. The layout of connection symbols depicting relationships among classes is done completely automatically; a connection symbol's layout is not changed as long as the order of the connection's class symbols does not change.

Conclusions

This paper examines support for collaboration across multiple sites when developing automotive software, focussing on the issue and importance of model merging.

In order to understand the way developers used layout we examined two substantial industrial projects (see section four). The main generic finding was that modellers use layout to convey meaning, often in a way that is not defined by given model heuristics (such as guidance on the production of UML class diagrams). Having established the importance of layout we then wanted to enable modellers to work independently on certain models in parallel.

Therefore, we present an approach for laying out models (class diagrams) in a semi-automatic fashion that allows modellers to manually define the order of class symbols and at the same time allows diagrams to be merge-able. This approach provided a trade-off between (1) the amount of layout freedom modellers had regarding the position of diagram symbols and (2) the ability to automatically create 'meaningful' merged diagrams whose layout was untangled -and preserved the manually defined class symbol hierarchy. In addition, an approach to visualising differences and conflicts between 'to-be-merged' UML models and class diagrams was implemented. This allowed the developers to work with merged models in the same way that modellers work with them when they create them in the first place, and crucially allowed developers to exchange partially merged models.

In summary, this paper has provided evidence for the importance of layout in models and has presented a 'semi-automatic' approach to merging which allows modellers to retain a greater recognition and understanding of their work when models across sites are merged. In addition, by allowing the exchange of partially merged models conflicts between versions can be resolved effectively. We contend that such merging is a vital cog in the support for collaborative development processes.

Fig. 1

 1 shows a merge example. The screen-shot shows four UML class diagrams: the initially merged diagram is shown in the upper-right corner, both evolved diagrams are in the lower half, and their common ancestor diagram is shown in the upper-left corner. The latter three diagrams are immutable, only the merged diagram and its underlying model can be modified by the modeller. Modifications are necessary to resolve merge conflicts. Both evolved diagram versions and the ancestor diagram are annotated with change and conflict information. Diagram symbols and model elements deleted in one or both evolved diagrams are highlighted and annotated in the ancestor version -since they are not part of evolved diagram (in which they got deleted). Any other changes are highlighted and annotated in the evolved diagrams. Conflicting changes are highlighted in a different colour to nonconflictingly ones.

Fig. 1 :

 1 Fig. 1: Merged diagram example (also shown: evolved diagram versions and their common ancestor with change and conflict annotations)


Reza Sahandi
email: rsahandi@bournemouth.ac.uk

Adel Alkhalil
email: aalkhalil@bournemouth.ac.uk

SMEs' Perception of Cloud Computing: Potential and Security

Keywords: Cloud computing security, cloud computing services, SMEs

Cloud computing is a new paradigm for emerging technology in the computing and IT industries. Cloud computing offers a new pathway for business agility and supports a faster time to market by offering ready-to-consume cloud-based IT services. SMEs can wisely take advantage of the cloud computing services, without the need for upfront costs. The perception of cloud computing from an SME stance is explored. The potential and concerns surrounding the adoption of cloud computing are discussed. A survey of SMEs conducted in the UK by the authors shows SMEs interests in exploiting the cloud computing services, but there are still some concerns with regards to security and vendor lock-in. This could have affected the speed of cloud computing being adopted.

Introduction

The dynamic force in the contemporary business market is rapidly eroding competitiveness, thereby causing products and skills to become obsolete [START_REF] Pauly | T-Systems Cloud-Based Solutions for Business Applications[END_REF]. Organisations are under pressure to find and implement new strategic ideas at an even faster pace to gain the competitive edge over their rivals within the global market. In order to increase competitiveness, organisations need to rationalise output to reduce costs, enhance process innovation and incorporate new technologies. Organisations in search of this competitive edge are continually putting pressure on their IT departments to provide new solutions that are deemed to be more flexible, efficient and cost-effective, enabling even faster time to market. This process is often referred to as realising "business agility". A flexible IT infrastructure can remove some of the barriers to global competition and allow smaller businesses to be efficient, competitive and also provide a degree of flexibility. Cloud computing has the potential to play a major role in addressing inefficiencies and make a fundamental contribution to the growth and competitiveness of organisations.

Small and Medium-sized Enterprises (SMEs) play a vital role in the European economy by fostering competitiveness and employment. SMEs are often confronted with difficulties in obtaining capital for the early start-up phases due to their small size [START_REF]Commission: The New SME Definition: User Guide and Model Declaration[END_REF] which may restrict their access to new technologies or innovations. By adopting cloud computing service models, SMEs will be able to avoid large up-front costs on IT resources for their production needs and business model of innovation.

Much of the research on cloud computing has concentrated on two broad issues: i) business agility and ii) catalysts for more innovation. However, difficulties still exist in deciding on the approach for implementing cloud computing service offerings for SMEs. To assist SMEs to adopt cloud computing services, this study aims to answer the research question: "How do SMEs perceive 'Cloud Computing'?". The findings of this research are expected to assist smaller companies in their adoption of cloud computing services; they may also inform service providers with respect to end-users' concerns. A survey of SMEs was conducted to explore the views and concerns they had for the adoption of cloud computing and results analysed (see section 3). This is followed by some discussion on how to rectify the shortcomings and concerns, particularly in the areas of security and vendor lock-in.

The paper is organized as follows. Section 2 presents the concept of cloud computing in a wider context. Section 3 presents a survey that explored the views and concerns of cloud computing services. Section 4 discusses the main issues hindering cloud computing adoption. The conclusions drawn from the research and survey analysis are presented in Section 5.

The Concept of Cloud Computing

Cloud computing is an all-embracing and rapidly evolving concept; hence the understanding of cloud computing by SMEs can assist in their approaches for cloud computing services utilisation [START_REF] David | Cloud computing Key Initiative Overview[END_REF]. The idea behind cloud computing is based on a set of many pre-existing and well researched concepts such as distributed and grid computing and virtualization. Although many of the concepts do not appear to be new, the real innovation of cloud computing lies in the way it provides computing services to customers [START_REF] Leimeister | The Business Perspective of Cloud Computing: Actors, Roles and Value Networks[END_REF]. The National Institute of Standards and Technology (NIST) has provided a commonly agreed definition of cloud computing that is "a model for enabling convenient, on-demand network access to a shared pool of configurable computing resources that can be rapidly provisioned and released with minimal management effort or service provider interaction" [START_REF] Mell | The NIST Definition of Cloud Computing[END_REF].

However, organisations and enterprises are often being confronted by conflicting and exaggerated claims of how cloud computing will dramatically transform their industries. Therefore, it should be mentioned that the marketing hype and meagre analyses from many vendors, IT analysts and users have an impact on the obscurity of the cloud capability and incumbent issues. Nevertheless according to the survey conducted in this paper (see section 3), just over half of the surveyed SMEs (51.5%) claimed to know what cloud computing is, whereas 25.1% were not sure about its term and 23.4% have no knowledge about it. A survey conducted by ACCA [START_REF]ACCA: A Digital agenda for European SMEs[END_REF] also paints a similar picture with just over 50% of respondents saying that SMEs have very limited or no understanding of cloud computing.

In spite of the ambiguity of understanding of the cloud computing concept, industry research giants including Gartner, Forrester and other industry research analysts predicted that a substantial number of the world's top enterprises would have migrated their IT needs to the cloud offerings by 2011 [START_REF] Mohan | Migrating into a Cloud[END_REF]. Moreover, a recent study conducted by Craig shows that there is an increase of 14% of SMEs in understanding cloud computing [START_REF] Craig | How Are SMBs Viewing the Cloud? Available online at[END_REF].

Cloud Computing From SMEs Perspective (the survey)

The survey attempted to explore the requirements of SMEs and their concerns in respect of cloud computing services. The study investigated the driving factors that encouraged SMEs to move to cloud computing services or hindering their adoption. The methodology employed was based on a quantitative online survey questionnaire approach. The target population consisted of SMEs situated within the United Kingdom. Participants varied between IT decision-makers and managers within their respective business enterprise. The group incorporated participants from organisations of different sizes and from diverse industry sectors. 300 SMEs were invited to participate in the survey. A total of 169 SMEs responded by completing the questionnaire. This gives a satisfactory response rate of 56% for this type of survey where response rates below 15% become questionable [START_REF] Perry | Technical and social bonds within business-tobusiness relationships[END_REF]. Table 1 provides a sociodemographic profile of the organisations and participates in the survey. The sample was slightly dominated by SMEs sized between 51 to 250 employees.

Why Should SMEs Adopt Cloud Computing Services?

Cloud computing offers a new pathway to business agility and supports a faster time to market by offering ready-to-consume cloud enabled resources such as IT infrastructure as a service, software platforms, and business applications. These services can all be accessed on-demand and provide support to new business requirement far faster than acquiring, installing, configuring and operating IT resources in house [START_REF] Lozano | Executive's Guide to Cloud Computing[END_REF]. Clearly, this is an attractive proposition to the organisations where upfront spending for Information and Communication Technology (ICT) is an issue, especially SMEs. Business agility is the key to commercial success and the current economic downturn has heightened its importance for SMEs. To survive, SMEs need to decrease time-to-market. Therefore, if "the cloud" is used appropriately within an overall IT strategy, it can provide a real competitive advantage, improve business performance and control the cost of IT resources for the organisation [START_REF] Brookbanks | More Clouds Coming[END_REF]. Cloud computing can also provide the IT resources required for a scalable business growth. The cloud is capable of providing a degree of flexibility for IT resources which would allow organisations to adapt to changing demands of their business needs. In addition, the cloud comes with high speed of implementation and ease of upgrading. Cloud services would also eliminate the need for expensive equipments to be located at the company's site. Furthermore, cloud computing can enable SMEs to focus on innovation and creation of new business, thereby enhancing productivity without requiring frequent updates of IT resources, servers and software licenses.

In order to observe the motivations of SMEs for adopting cloud-based services, the survey raised the question of "what were the reasons behind using cloud computing". Figure 1 shows the analysis of the reasons that the SMEs provided. As can be seen in Figure 1, cost reduction (45.5%), mobility and convenience in accessing applications (44.9%) appear to be the key reasons behind SMEs adopting cloud computing services. This signifies that SMEs find cloud computing a strategic idea for reducing the cost of IT infrastructures and operation. In agreement with this finding, a recent study conducted by Craig [START_REF] Craig | How Are SMBs Viewing the Cloud? Available online at[END_REF] concluded that cost reduction is still the top priority for SMEs. The ability for cloud users gaining convenient access from anywhere and at any time were also found to be a key reason for adopting cloud computing. This indicates that SMEs are interested in access to applications and data from anywhere, on-demand, through cloud computing. Therefore, the cloud is remarkably an ideal IT solution for businesses whose employees require on-demand remote access to tools and data.

SMEs find ubiquity and flexibility in the cloud fascinating too (38.9%). This indicates the need for innovative solutions that would enable SMEs to gain the competitive advantage over their rivals. Increasing computing capacity and providing greater IT efficiency were also found to be important reasons for using Cloud computing services (32.9%) and (31.7%) respectively.

Concerns for Adopting Cloud Computing

Despite the enormous advantages that the cloud can offer, cloud computing adoption has been at a slower rate from what had been expected [START_REF] Gogrid | Cloud computing adoption slower than expected[END_REF]. In order to determine which issues mostly affect the adoption of cloud computing, the study further explored SMEs' concerns of cloud-based services. Figure 2 illustrates issues raised by participants hindering the cloud computing adoption rate. Security and vender lock-in were raised by SMEs as their major concerns. Moreover, SMEs have also shown concern of other aspects regarding the adoption of cloud computing. These concerns were not found as significant as security and vender lock-in; therefore they are not included in the discussion. Figure 2 shows that 54.6% (the second largest percentage response to any question asked in the research) of the surveyed SMEs indicated data protection and privacy as the number one reason for not considering cloud-based IT as a service. In contrast to the traditional provision of onsite IT resources, the multi-tenant nature of cloud computing usually raises the question in respect of privacy, confidentiality and data integrity. Cloud computing presents its own set of security issues coupled with the risk and threats inherent in traditional IT computing. The fact that consumers can tap into cloud services using Web browsers, shows the benefits of mobility and convenience on the one hand, but on the other, it has raised issues concerning data privacy and security Moreover, about half of the surveyed SMEs consider vender lock-in as a major concern for adopting cloud computing. Cloud computing users are concerned about losing control of their data that could be locked-in by a cloud provider. Although the cloud providers implement up-to-time and a secure IT infrastructure; consumers continue suffering from the loss of control and lack of trust problems [START_REF] Almorsy | Collaboration-Based Cloud Computing Security Management Framework[END_REF]. To further substantiate on this matter in agreement with StarUK [START_REF]Star UK:Can Cloud Computing give you the freedom to be more strategic? -UK businesses' attitudes to Cloud Computing revealed[END_REF], "for many people, the issue is one of control: many IT managers believe that if something is not under their direct oversight, then they cannot know if it is secure until it has been compromised: which is sometimes the hallmark of a put upon, reactive, service-based culture". The subsequent section provides further considerations with respect to these key issues. Security and data privacy are often presented as the key risks when outsourcing IT services that may include critical data. These risks have made data privacy and security the main issues delaying cloud computing adoption [START_REF] Sabahi | Cloud Computing Security Threats and Responses[END_REF]. The fact that before data can get into the cloud, it has to progress outside a company's firewall via an access network and can be prone to attacks. For example, the most common way of accessing the cloud is through a web browser. Therefore, cloud services may share much vulnerability as any website, such as SQL injection or cross-site scripting (XSS) [START_REF] Devine | Flying too Close to the Sun Can be a Risky Business[END_REF]. The cloud also relies on virtual machines (VMs), which mean any compromises in the set up of the software used could cause unauthorised access to sensitive data.

Normally, cloud computing providers have multiple data centres at different geographical locations in order to optimally serve consumers' needs around the world. In most cloud service scenarios, consumers have no idea of where there data is stored. Therefore, legal and regulatory issues arise which require careful consideration because the physical location of data centres determines the set of laws that can govern the management of data.

Cloud computing comprises of different deployment models, nevertheless each service comes with its own security issues. Thus, to guarantee the security of corporate data in the cloud is difficult, if not impossible [START_REF] Kandukuri | Cloud Security Issues[END_REF]. In Infrastructure as a Service (IaaS) model, for example, the security responsibility of the underlying infrastructure and abstraction layers belong to the cloud service provider, while the remainder of the stack is the consumer's responsibility. Organisations, before moving applications outside their corporate firewalls, should be aware of the data intrusion risks associated with such an environment. IaaS cloud models are prone to attacks like XML Signature Element Wrapping [START_REF] Mcintosh | XML Signature Element Wrapping Attacks and Countermeasures[END_REF] -this is a well-known attack on protocols using XML Signature such as SOAP (that stands for Simple Object Access Protocol) messages. These protocols are used to provide authentication for messaging through the web.

With Platform as a Service (PaaS) model, the security of the platform used for development is the service provider's responsibility, but the security of the applications developed is the responsibility of the consumers. Concerns about cloud service integrity and binding issues with PaaS' cloud models should be given further consideration. PaaS models are prone to cloud malware injection attacks and metadata spoofing attack as described by Jensen [START_REF] Jensen | On Technical Security Issues in Cloud Computing[END_REF].

In Software-as-a-Service (SaaS) model, the service provider is responsible for, not only providing physical and environmental security capabilities, but also addresses the security control on the infrastructure, applications and data. According to a Forrester research, security concerns are the most commonly cited reason why enterprises are not interested in SaaS [START_REF]Forrester Research: Top Corporate Software Priority Is Modernizing Legacy Applications[END_REF]. A major concern of SaaS is unauthorised access due to data being transferred to a remote server thought the internet. This might allow adversaries to obtain passwords, inspect data, and modify or damage the data. This would be more harmful in case of unauthorised access to sensitive information such as payments details and information on human resources. Denial of service attacks and network failure present the availability concern of SaaS.

There are a number the security measures which can be developed and implemented to tackle the above security issues. For example, implementing a robust authentication mechanism, encrypted protocols, secure backup applications and secure physical resources could improve security. Access control can be enhanced by incorporating security measures to the network layers. Web Services Security (WSS) is a security technique that can be incorporated to SOAP messages to assure the integrity and confidentiality by signing and encrypting their context [START_REF]Guide to secure web services[END_REF]. The confidentiality and integrity can also be improved by incorporating cryptographic protocols such as (TLS) Transport Layer Security, and (SSL) Secure Socket Layer to the transport layer. Moreover, it is highly recommended that cloud providers protect the integrity of consumers' data by complying with relevant standards including Payment Card Industry -Data Security Standards [START_REF] Jansen | Guidelines on Security and Privacy in Public Cloud Computing[END_REF]. In [START_REF] Al Morsy | An Analysis of The Cloud Computing Security Problem[END_REF] it is also recommended to adopt the standards for identifying and accessing management such as SPML, SAML, OAuth, and XACML. These standards could increase the security of the identity federation among different cloud platforms. Securing the VMs is critically important to avoid unauthorised access, so it is vital to consider security practices that may include enabling perimeter defence on VMs. Other security practises maybe considered such as implementing file integrity checks and maintaining backups. On the other hand, SMEs should ensure the security aspects of their side that include firewall configurations, reliable and high bandwidth internet connections, and upgrading their software.

Vendor Lock-In

The lack of standards in cloud computing may raise interoperability and manageability issues inside and between cloud providers, with possible economic impacts. Interoperability is concerned with the migration and integration of applications and data between different vendor's clouds. Whereas standardisation strives to support applications by different service vendors to interoperate with one another, exchange traffic and cooperatively interact with data, as well as protocols, for joint coordination and control [START_REF] Yoo | Cloud Computing: Architectural and Policy Implications[END_REF].

In the absence of standardisation, SMEs willing to outsource and combine the range of services from different cloud providers to achieve maximum efficiency, will experience difficulty when trying to get their in-house (legacy) systems to interact with the cloud providers system. Likewise, the lack of standardization may also bring disadvantages, when migration, integration, or exchanges of resources are required. The main negative aspect is the necessity of factoring applications to comply with other cloud Application Programming Interfaces (APIs), which can possibly lead to higher costs, delays and risks, thus opposing agility, efficiency, and low costs [START_REF] Machado | Considerations on the Interoperability of and between Cloud Computing Standards[END_REF]. In the aforementioned, reconfiguration of systems and applications to achieve interoperability are time consuming and thus, require a considerable amount of expertise, which could be challenging for SMEs. Further, interoperability and portability will give rise to standard reusability, which in turn will lead to faster cloud deployment [START_REF] Craig | constructing cloud computing[END_REF].

Conclusion

The concept of cloud computing was briefly discussed. A survey of 300 SMEs showed their motivations and concerns for adopting cloud computing services. The results of the survey show that SMEs are highly interested in cloud computing enabling them to reduce costs, improve accessibility, flexibility and scalability. These benefits are seen by SMEs as key driving factors in adopting cloud computing services. However, the rapid increase in corporate data, placed in the cloud, has raised issues concerning security, vendor lock-in, and complications with data privacy and data protection. Consequently, this resulted in the slow growth of cloud computing adoption.

In order to convince more SMEs to migrate their systems to the cloud, these issues need to be addressed. The privacy challenge for cloud-based software architects, demands the design of a service were security risks are reduced, whilst ensuring legal compliance. In other words, safety of data should be placed at the front and in the centre of the design process of any cloud service. Security can be enhanced by developing existing security measures such as perimeter defence on VMs, data encryption, backups, incorporating cryptographic protocols such as TLS, SSL, and WSS. Furthermore, implementing a standardised framework for cloud services will support seamless cloud service integration between different vendor platforms. This would allow cloud users to switch from one provider to another.

Cloud computing is still a new technological venture for SMEs, but it takes good business sense and appropriate steps to fully reap its benefits. Whenever security, data privacy, interpretability, and portability standards ameliorate, cloud computing adoption will proliferate.

Fig. 1 :

 1 Fig. 1: Drivers for Cloud Computing Adoption by UK SMEs.

Fig. 2 :

 2 Fig. 2: Barriers to Cloud Computing Adoption in UK

Table 1 -

 1 Socio-Demographic Profile of Participant Organisation

	Organisation Size	Percentage
	1 -24	20.5%
	25 -50	19.3%
	51 -250	41.0%
	More than 250	19.3%
	Total:	100%
	Organization Sector	Percentage
	Manufacturing and industrial market	15.6%
	Financial services	3.0%
	Public sector & healthcare	11.6%
	Business sector	22.3%
	ICT services	15.0%
	Trading sector	7.8%
	Other	24.7%
	Total:	100%