In the domain of IoT a major objective is the interconnection of a variety of devices with higher level applications. Therefore, several IoT middleware systems have been developed. These IoT integration middleware systems are heterogeneous, e.g., in terms of the supported transport protocols. Thus, IoT environments often differ due to the utilized middleware. As a result, by deploying applications in different environments the communication clients on the application side have to be adjusted manually. This leads to a greater development effort for each deployment and hampers the application's portability. In this paper, we present a generic driver injection concept to enable the development of portable IoT applications and the automated deployment in different environments without manual adaptation efforts. For this, a programming model and a deployment modeling concept are introduced. We demonstrate the feasibility of our approach with a TOSCA-based prototype.

With Cloud Computing, offering and delivering services over the Internet became commonly feasible. This has impacts on application design, development as well as on the automation of application provisioning. The Twelve-Factor App is a methodology that documents best practices for building and operating scalable, maintainable, and portable web-based SaaS applications. However, a standards-based approach to build, release, and run Twelve-Factor Apps independently of individual cloud providers and specific deployment technologies is missing, which quickly leads to a vendor or technology lock-in. In this paper, we introduce a guideline to establish a development process using the Twelve-Factor App methodology together with the OASIS standard TOSCA to address this issue. We show how to realize the twelve factors with TOSCA and how the approach supports portability and automated deployment.

The automation of business processes is of vital importance for organizations to speed up their business and to lower costs. Due to emerging technologies in the field of Internet of Things, changing situations can be recognized automatically, which provides the basis for an automated adaptation of process executions in order to react to changing circumstances. Although approaches exist that enable creating self-adapting workflows, a systematic modelling approach that supports the specification of situational dependencies directly in workflow models is missing. In this paper, we tackle this issue by presenting a modelling extension called SitME that defines (i) an extensible Situation Event type, (ii) the concept of Situational Scopes, and (iii) a visual notation. As the introduced extension is language-independent, we apply the approach to BPEL to validate its practical feasibility.

Processes involving knowledge workers, such as decision-making processes, research processes, development processes, maintenance processes, etc. play a critical role for many organizations because they represent a valuable amount of the work an organization delivers. Therefore, supporting and automating such processes is vitally important for organizations. In our previous work, we have proposed a resource-centric approach called Informal Process Essentials (IPE) to support and to provide a certain degree of automation. The approach enables specifying required resources including autonomous agents of an informal process for accomplishing process goals through creating and initializing IPE models. Initializing an IPE model results in the acquirement of resources that collaboratively work towards the goals specified by the model. In this work, we provide an approach to automating the enactment of such resource-centric informal processes in two steps: (i) integrating resources of informal processes and (ii) executing informal processes. The approach we introduce enables the inclusion of different resource domains, e.g., IT resources, human resources, etc., and resource deployment environments, e.g., OpenTOSCA, Docker, etc. to model and enact informal processes. During the execution, the resources made available through the integration are acquired and engaged for goals of modeled informal processes. To validate the introduced concepts, we apply the approach to a detailed case study that realizes these two steps based on existing approaches and technologies, in particular, the OpenTOSCA ecosystem, an knowledge base, and an APIfication approach.

Leading paradigms to develop, deploy, and operate applications such as continuous delivery, configuration management, and the merge of development and operations (DevOps) are the foundation for various techniques and tools to implement automated deployment. To make such applications available for users and customers, these approaches are typically used in conjunction with Cloud computing to automatically provision and manage underlying resources such as storage and virtual servers. A major class of these automation approaches follow the idea of converging toward a desired state of a resource (e.g. a middleware component deployed on a virtual machine). This is achieved by repeatedly executing idempotent scripts to reach the desired state. Because of major drawbacks of this approach, we discuss an alternative deployment automation approach based on compensation and fine-grained snapshots using container virtualization. We perform an evaluation comparing both approaches in terms of difficulties at design time and performance at runtime. Moreover, we discuss concepts, strategies, and implementations to effectively combine different deployment automation approaches.

Web services privacy issues have been attracting more and more attention in the past years. Since the number of Web services-based business applications is increasing, the demands for privacy enhancing technologies for Web services will also be increasing in the future. In this paper, we investigate an extension of business protocols, i.e. the specification of which message exchange sequences are supported by the web service, in order to accommodate privacy aspects and time-related properties. For this purpose we introduce the notion of Timed Privacy-aware Business Protocols (TPBPs). We also discuss TPBP properties can be checked and we describe their verification process.

In this paper we describe a method and corresponding tool chain that allows moving an application to the cloud. In particular, we support to split an application such that various parts of it are moved to different clouds. This split can be done manually or by support of optimization algorithms. The split application is then automatically provisioned in the different target clouds. A metamodel for such applications supporting the proposed method is introduced. The architecture of a supporting tool is described. Experiences from the usage of the proposed method are reported.

In simulations scientific workflows are used to coordinate complex implementations incorporating different kinds of simulations. Typically, the amount of data to be analyzed is huge and it is impossible to store all intermediate or alternative results. Thus, the access to data services has to be coordinated such that applications read the right data and do not overwrite one another. In this paper, we present a possibility to coordinate different scientific simulations accessing and updating the same data using existing Web service technologies: We extend the concept of choreography spheres by allowing control-links between them and the property "permeability" stating whether a cross-boundary link may be traversed before the start or completion of a choreography sphere. This paper is the first presenting a state model for choreography spheres.

The performance of applications is influenced by the way its operations are grouped into global transactions. This in turn influences the performance of business processes which utilize these applications as implementations of process activities/steps. Stratified transactions, as produced by the stratification approach presented in this paper, is a way to manage a global transaction by combining the more elemental transactions coordinated using the two-phase commit protocol and queued transactions. The stratification approach can be applied for optimally fragmenting workflow-based service compositions and support the out- and in-sourcing scenarios. This paper formally models global transactions and investigates the mechanisms for building an optimally stratified transaction relying on formally defined evaluation criteria. We investigate the applicability of local search algorithms to the optimization of transaction stratification. In particular we consider hill-climbing, simulated annealing, and a novel hybrid method combining both approaches.

Reuse of proven process models increases modeling efficiency and ensure the quality of process models. To provide a better support for reuse, the retrieval mechanisms of process repositories should be able to propose similar process models that ranked according to their similarity degrees to the query request. As a process model and a query request on process structure can both be viewed as rooted, directed, and acyclic graphs, the problem of querying structural information of BPEL processes can be reduced to a graph matchmaking problem. In this paper we present a novel and efficient graph-based algorithm for querying structural information of BPEL processes based on an incomplete matchmaking semantics. Our algorithm performs in the worst case in polynomial time in the orders of the query graph and the process graph.

Currently, several vendors and projects are building proprietary SaaS platforms where more and more applications are hosted in a Software as a Service business model. However, these proprietary platforms prevent that applications offered by different SaaS application vendors can be easily reused on the platforms offered by the different SaaS hosting providers. In this paper we describe a package format for composite configurable SaaS application packages for applications developed following a service oriented architecture. We show how the service component architecture (SCA) can be extended with variability descriptors and SaaS multi-tenancy patterns to package and deploy multi- tenant aware configurable composite SaaS applications.

The Web Service Description Language (WSDL) provides means to describe functional aspects of a service in a service oriented architecture (SOA) based on Web service technology. In contrast to its predecessor (WSDL 1.1), WSDL 2.0 does not define a fixed set of operation types but provides for a generic mechanism to define an operation by means of message exchange patterns (MEPs). In this paper we compare the expressivity of MEPs in general with other work and formalisms in the field of service interaction. Furthermore, we identify new MEPs and extend the template used to define MEPs to allow expressing more complex patterns. We give a refined definition of MEPs based on a detailed discussion and discuss how WSDL and the MEPs in particular can be combined with the choreography approach.

Petri Nets are a formalism for describing coordinated interactions between independent entities, called transitions, by means of synchronized token exchange through places. Tuplespaces are an abstraction of the shared memory concept providing means for loosely-coupled coordination between individual components. In the tuplespace model, coordination between applications is achieved by production and blocking consumption of tuples which are communicated over tuplespace buffers. On the basis of the conceptual similarities of Petri nets and tuplespaces, we investigate in this paper whether on the one hand Petri nets are a suitable notation for modeling tuplespace-based applications; on the other hand, we argue that tuplespaces are a suitable platform for execution of applications modeled as Petri net-based workflows by describing and evaluating two approaches to execute Petri nets using tuplespace-based middleware.

Recent technology trends in the Web Services (WS) domain indicate that a solution eliminating the presumed complexity of the WS-* standards may be in sight: advocates of REpresentational State Transfer (REST) have come to believe that their ideas explaining why the World Wide Web works are just as applicable to solve enterprise application integration problems and to simplify the plumbing required to build service-oriented architectures. In this paper we objectify the WS-* vs. REST debate by giving a quantitative technical comparison based on architectural principles and decisions. We show that the two approaches differ in the number of architectural decisions that must be made and in the number of available alternatives. This discrepancy between freedom-from-choice and freedom-of-choice explains the complexity difference perceived. However, we also show that there are significant differences in the consequences of certain decisions in terms of resulting development and maintenance costs. Our comparison helps technical decision makers to assess the two integration styles and technologies more objectively and select the one that best fits their needs: REST is well suited for basic, ad hoc integration scenarios, WS-* is more flexible and addresses advanced quality of service requirements commonly occurring in enterprise computing.

Continuous process improvement (CPI) may require a BPEL process to be split amongst different participants. In this paper, we enable splitting standard BPEL — without requiring any new middleware for the case of flat flows. The solution also supports splitting loops and scopes that have compensation and/or fault handlers. When splitting loops and scopes, we extend existing Web services standards and frameworks in a standard compliant manner in order to support the resulting split control (not data) between the fragments. Data dependencies, however, are handled directly using BPEL constructs placed in the fragments even for split loops and scopes. We present a solution that uses a BPEL process, partition information, and results of data-flow analysis to produce a BPEL process for each participant. The collective behavior of these participant processes recreates the control and data flow of the non-split process. Previous work presented process splitting using a variant of BPEL where data flow is modeled explicitly using "data links". We reuse the control flow aspect from that work as well as the control flow aspect from our work on splitting loops and scopes, focusing in this paper on maintaining the data dependencies in standard BPEL.

Service-Oriented Computing (SOC) is a new computing paradigm that utilizes services as the basic constructs to support the development of rapid, low-cost and easy composition of distributed applications even in heterogeneous environments. The promise of Service-Oriented Computing is a world of cooperating services where application components are assembled with little effort into a network of services that can be loosely coupled to create flexible dynamic business processes and agile applications that may span organizations and computing platforms. The subject of Service-Oriented Computing is vast and enormously complex, spanning many concepts and technologies that find their origins in diverse disciplines that are woven together in an intricate manner. In addition, there is a need to merge technology with an understanding of business processes and organizational structures, a combination of recognizing an enterprise's pain points and the potential solutions that can be applied to correct them. The material in research spans an immense and diverse spectrum of literature, in origin and in character. As a result research activities are very fragmented. This necessitates that a broader vision and perspective be established — one that permeates and transforms the fundamental requirements of complex applications that require the use of the Service-Oriented Computing paradigm. This paper provides a Service Oriented Computing Roadmap and places on-going research activities and projects in the broader context of this roadmap. This research roadmap launches four pivotal, inherently related, research themes to Service-Oriented Computing: service foundations, service composition, service management and monitoring and service-oriented engineering.

The Sarbanes-Oxley Act instituted a series of corporate reforms to improve the accuracy and reliability of financial reporting. Sections 302 and 404 of the Act require SEC-reporting companies to implement internal controls over financial reporting, periodically assess the effectiveness of these internal controls, and certify the accuracy of their financial statements. We suggest that database technology can play an important role in assisting compliance with the internal control provisions of the Act. The core components of our solution include: (i) modeling of required workflows, (ii) active enforcement of control activities, (iii) auditing of actual workflows to verify compliance with internal controls, and (iv) discovery-driven OLAP to identify irregularities in financial data. We illustrate how the features of our solution fulfill Sarbanes-Oxley requirements using several real-life scenarios. In the process, we identify opportunities for new database research.

Production workflow management systems must be scalable, highly available and reliable. We sketch the architecture of such a system that is built entirely on message-oriented middleware and relational database management technology.