Delegation Protocols in Human-Centric Workflows

International audienceOrganisations are facilitated and conducted using workflow management systems. Currently, we observe a tendency moving away from strict workflow modelling towards dynamic approaches supporting human interactions when deploying a workflow. One specific approach ensuring human-centric workflows is task delegation. Delegating a task may require an access to specific and potentially sensitive data that have to be secured and specified into authorisation policies. In this paper, we propose a modelling approach to secure delegation. In doing so, we define delegation protocols supporting specific constraints based on both workflow and access control systems. Moreover, we develop an advanced access control framework to integrate delegation constraints within existing policies. The novelty consists in the proactivity aspect of our framework to cope with dynamic delegation of authority in authorisation policies

Cloud Process Execution Engine: Architecture and Interfaces

Process Execution Engines are a vital part of Business Process Management (BPM) and Manufacturing Orchestration Management (MOM), as they allow the business or manufacturing logic (expressed in a graphical notation such as BPMN) to be executed. This execution drives and supervises all interactions between humans, machines, software, and the environment. If done right, this will lead to a highly flexible, low-code, and easy to maintain solution, that allows for ad-hoc changes and functional evolution, as well as delivering a wealth of data for data-science applications. The Cloud Process Execution Engine CPEE.org implements a radically distributed scale-out architecture, together with a minimal set of interfaces, to allow for the simplest possible integration with existing services, machines, and existing data-analysis tools. Its open-source components can serve as a blueprint for future development of commercial solutions, and serves as a proven testbed for academic research, teaching, and industrial application since 2008. In this paper we present the architecture, interfaces that make CPEE.org possible, as well as discuss different lifecycle models utilized during execution to provide overarching support for a wide range of data-analysis tasks.Comment: 30 pages, 12 figures, 2 illustration

Bayesian Process Networks: An approach to systemic process risk analysis by mapping process models onto Bayesian networks

This paper presents an approach to mapping a process model onto a Bayesian network resulting in a Bayesian Process Network, which will be applied to process risk analysis. Exemplified by the model of Event-driven Process Chains, it is demonstrated how a process model can be mapped onto an isomorphic Bayesian network, thus creating a Bayesian Process Network. Process events, functions, objects, and operators are mapped onto random variables, and the causal mechanisms between these are represented by appropriate conditional probabilities. Since process risks can be regarded as deviations of the process from its reference state, all process risks can be mapped onto risk states of the random variables. By example, we show how process risks can be specified, evaluated, and analysed by means of a Bayesian Process Network. The results reveal that the approach presented herein is a simple technique for enabling systemic process risk analysis because the Bayesian Process Network can be designed solely on the basis of an existing process model

Bayesian Process Networks: An approach to systemic process risk analysis by mapping process models onto Bayesian networks

This paper presents an approach to mapping a process model onto a Bayesian network resulting in a Bayesian Process Network, which will be applied to process risk analysis. Exemplified by the model of Event-driven Process Chains, it is demonstrated how a process model can be mapped onto an isomorphic Bayesian network, thus creating a Bayesian Process Network. Process events, functions, objects, and operators are mapped onto random variables, and the causal mechanisms between these are represented by appropriate conditional probabilities. Since process risks can be regarded as deviations of the process from its reference state, all process risks can be mapped onto risk states of the random variables. By example, we show how process risks can be specified, evaluated, and analysed by means of a Bayesian Process Network. The results reveal that the approach presented herein is a simple technique for enabling systemic process risk analysis because the Bayesian Process Network can be designed solely on the basis of an existing process model

The CHORCH Approach: How to Model B2Bi Choreographies for Orchestration Execution

The establishment and implementation of cross-organizational business processes is an implication of today's market pressure for efficiency gains. In this context, Business-To-Business integration (B2Bi) focuses on the information integration aspects of business processes. A core task of B2Bi is providing adequate models that capture the message exchanges between integration partners. Following the terminology used in the SOA domain, such models will be called choreographies in the context of this work. Despite the enormous economic importance of B2Bi, existing choreography languages fall short of fulfilling all relevant requirements of B2Bi scenarios. Dedicated B2Bi choreography standards allow for inconsistent outcomes of basic interactions and do not provide unambiguous semantics for advanced interaction models. In contrast to this, more formal or technical choreography languages may provide unambiguous modeling semantics, but do not offer B2Bi domain concepts or an adequate level of abstraction. Defining valid and complete B2Bi choreography models becomes a challenging task in the face of these shortcomings. At the same time, invalid or underspecified choreography definitions are particularly costly considering the organizational setting of B2Bi scenarios. Models are not only needed to bridge the typical gap between business and IT, but also as negotiation means among the business users of the integration partners on the one hand and among the IT experts of the integration partners on the other. Misunderstandings between any two negotiation partners potentially affect the agreements between all other negotiation partners. The CHORCH approach offers tailored support for B2Bi by combining the strengths of both dedicated B2Bi standards and formal rigor. As choreography specification format, the ebXML Business Process Specification Schema (ebBP) standard is used. ebBP provides dedicated B2Bi domain concepts such as so-called BusinessTransactions (BTs) that abstractly specify the exchange of a request business document and an optional response business document. In addition, ebBP provides a format for specifying the sequence of BT executions for capturing complex interaction scenarios. CHORCH improves the offering of ebBP in several ways. Firstly, the execution model of BTs which allows for inconsistent outcomes among the integration partners is redefined such that only consistent outcomes are possible. Secondly, two binary choreography styles are defined as B2Bi implementation contract format in order to streamline implementation projects. Both choreography styles are formalized and provided with a formal execution semantics for ensuring unambiguity. In addition, validity criteria are defined that ensure implementability using BPEL-based orchestrations. Thirdly, the analysis of the synchronization dependencies of complex B2Bi scenarios is supported by means of a multi-party choreography style combined with an analysis framework. This choreography style also is formalized and standard state machine semantics are reused in order to ensure unambiguity. Moreover, validity criteria are defined that allow for analyzing corresponding models for typical multi-party choreography issues. Altogether, CHORCH provides choreography styles that are B2Bi adequate, simple, unambiguous, and implementable. The choreography styles are B2Bi adequate in providing B2Bi domain concepts, in abstracting from low-level implementation details and in covering the majority of real-world B2Bi scenarios. Simplicity is fostered by using state machines as underlying specification paradigm. This allows for thinking in the states of a B2Bi scenario and for simple control flow structures. Unambiguity is provided by formal execution semantics whereas implementability (for the binary choreography styles) is ensured by providing mapping rules to BPEL-based implementations. The validation of CHORCH's choreography styles is performed in a twofold way. Firstly, the implementation of the binary choreography styles based on Web Services and BPEL technology is demonstrated which proves implementability using relatively low-cost technologies. Moreover, the analysis algorithms for the multi-party choreography styles are validated using a Java-based prototype. Secondly, an abstract visualization of the choreography styles based on BPMN is provided that abstracts from the technicalities of the ebBP standard. This proves the amenability of CHORCH to development methods that start out with visual models. CHORCH defines how to use BPMN choreographies for the purpose of B2Bi choreography modeling and translates the formal rules for choreography validity into simple composition rules that demonstrate valid ways of connecting the respective modeling constructs. In summary, CHORCH allows integration partners to start out with a high-level visual model of their interactions in BPMN that identifies the types and sequences of the BusinessTransactions to be used. For multi-party choreographies, a framework for analyzing synchronization dependencies then is available. For binary choreographies, an ebBP refinement can be derived that fills in the technical parameters that are needed for deriving the implementation. Finally, Web Services and BPEL based implementations can be generated. Thus, CHORCH allows for stepwise closing the semantic gap between the information perspective of business process models and the corresponding implementations. It is noteworthy that CHORCH uses international standards throughout all relevant layers, i.e., BPMN, ebBP, Web Services and BPEL, which helps in bridging the heterogeneous IT landscapes of B2Bi partners. In addition, the adoption of core CHORCH deliverables as international standards of the RosettaNet community give testament to the practical relevance and promise dissemination throughout the B2Bi community.Betriebsübergreifende Geschäftsprozessintegration ist eine logische Konsequenz allgegenwärtigen Wettbewerbsdrucks. In diesem Kontext fokussiert Business-To-Business integration (B2Bi) auf die Informationsaustausche zwischen Unternehmen. Eine B2Bi-Kernanforderung ist die Bereitstellung adäquater Modelle zur Spezifikation der Nachrichtenaustausche zwischen Integrationspartnern. Diese werden im Rahmen dieser Arbeit in Anlehnung an Service-orientierte Architekturen (SOA)-Terminologie Choreographien genannt. Bestehende Choreographiesprachen decken die Anforderungen an B2Bi-Choreographien nicht vollständig ab. Dedizierte B2Bi-Choreographiestandards definieren inkonsistente Austauschprozeduren für grundlegende Interaktionen und nur unvollständige Semantiken für fortgeschrittene Interaktionen. Formale oder Technik-getriebene Choreographiesprachen bieten die benötigte Präzision, lassen aber Domänenkonzepte vermissen oder operieren auf einer niedrigen Abstraktionsebene. Angesichts solcher Mängel wird die Spezifikation valider und vollständiger B2Bi-Choreographien zu einer echten Herausforderung. Gleichzeitig sind mangelhafte Choreographiemodelle gerade im B2Bi-Bereich besonders problematisch, da diese nicht nur zwischen Fach- und IT-Abteilung, sondern auch über Unternehmensgrenzen hinweg eingesetzt werden. Der CHORCH-Ansatz schafft an dieser Stelle mittels maßgeschneiderter Choreographien Abhilfe, welche die Vorteile von B2Bi-Choreographien und von formalen Ansätzen kombinieren. Als Ausgangspunkt wird das ebXML Business Process Specification Schema (ebBP) verwendet, das als B2Bi-Choreographiestandard Domänenkonzepte wie zum Beispiel sogenannte BusinessTransactions (BTs) bietet. Eine BT ist der Basisbaustein von B2Bi-Choreographien und spezifiziert den Austausch eines Geschäftsdokuments sowie eines optionalen Antwortdokuments. Darüber hinaus bietet ebBP ein Format zur Spezifikation von BT-Kompositionen zur Unterstützung komplexer Interaktionen. CHORCH erweitert ebBP wie folgt. Erstens, das Ausführungsmodell für BTs wird neu definiert, um inkonsistente Ergebniszustände zu eliminieren. Zweitens, für Entwicklungsprojekte werden zwei binäre Choreographieklassen definiert, die als B2Bi-Implementierungskontrakt dienen sollen. Die Formalisierung beider Klassen sowie formale operationale Semantiken gewährleisten Eindeutigkeit, während Validitätskriterien die Ausführbarkeit entsprechender Modelle mittels BPEL-basierter Orchestrationen garantieren. Drittens, zur Analyse der Synchronisationsbeziehungen komplexer B2Bi-Szenarien wird eine Multi-Party-Choreographieklasse nebst Analyseframework definiert. Wiederum wird für diese Klasse eine Formalisierung definiert, die mittels Standard-Zustandsautomatensemantik Eindeutigkeit gewährleistet. Ferner garantieren Validitätskriterien die Anwendbarkeit der definierten Analysealgorithmen. Insgesamt bieten die Choreographieklassen des CHORCH-Ansatzes ein B2Bi-adäquates, einfaches, eindeutiges und implementierbares Modell der Nachrichtenaustausche zwischen B2Bi-Partnern. B2Bi-Adäquatheit wird durch Verwendung von B2Bi-Domänenkonzepten, Abstraktion von rein technischen Kommunikationsdetails und Abdeckung der meisten praktisch relevanten B2Bi-Szenarien gewährleistet. Einfachheit ist ein Ausfluss der Verwendung eines Zustandsmaschinen-basierten Modellierungsparadigmas, das die Definition des Interaktionsfortschritts in Form von Zuständen sowie einfache Kontrollflussstrukturen ermöglicht. Eindeutigkeit wird durch die Verwendung formaler Semantiken garantiert, während Implementierbarkeit (für die beiden binären Choreographieklassen) durch Angabe von Mapping-Regeln auf BPEL-Orchestrationen sichergestellt wird. Die Validierung der CHORCH-Choreographieklassen erfolgt in zweierlei Hinsicht. Erstens, die Implementierbarkeit der binären Choreographieklassen mit Hilfe von Web Services und BPEL wird durch die Definition entsprechender Mappingregeln belegt. Weiterhin wird das Analyseframework der Multi-Party-Choreographieklasse als Java-Prototyp implementiert. Zweitens, für alle Choreographieklassen wird eine abstrakte Visualisierung auf BPMN-Basis definiert, die von diversen technischen Parametern des ebBP-Formats abstrahiert. Damit wird die Integrierbarkeit der CHORCH-Choreographieklassen in Entwicklungsansätze, die ein visuelles Modell als Ausgangspunkt vorsehen, belegt. CHORCH definiert, wie sogenannte BPMN-Choreographien zum Zweck der B2Bi-Choreographiemodellierung zu verwenden sind und übersetzt die Validitätskriterien der CHORCH-Choreographieklassen in einfache Modell-Kompositionsregeln. In seiner Gesamtheit bietet CHORCH somit einen Ansatz, mit Hilfe dessen B2Bi-Partner zunächst die Typen und zulässigen Reihenfolgen ihrer Geschäftsdokumentaustausche auf Basis eines abstrakten visuellen BPMN-Modells identifizieren können. Im Fall von Multi-Party-Choreographien steht dann ein Framework zur Analyse der Synchronisationsbeziehungen zwischen den Integrationspartnern zur Verfügung. Im Fall von binären Choreographien können ebBP-Verfeinerungen abgeleitet werden, welche die Modelle um technische Parameter anreichern, die zur Ableitung einer Implementierung benötigt werden. Diese ebBP-Modelle sind in Web Services- und BPEL-basierte Implementierungen übersetzbar. Damit erlaubt CHORCH die schrittweise Überbrückung der semantischen Lücke zwischen der Informationsaustauschperspektive von Geschäftsprozessmodellen und den zugehörigen Implementierungen. Ein beachtenswerter Aspekt des CHORCH-Ansatzes ist die Verwendung einschlägiger internationaler Standards auf allen Abstraktionsebenen, im Einzelnen BPMN, ebBP, Web Services und BPEL. Die Verwendung von Standards trägt dem heterogenen Umfeld von B2Bi-Szenarien Rechnung. Zusätzlich wurden Kernergebnisse des CHORCH-Ansatzes als internationale Standards der RosettaNet-B2Bi-Community veröffentlicht. Dies belegt die praktische Relevanz des Ansatzes und fördert die Verbreitung innerhalb der B2Bi-Community

Cross-formalism resource discovery in smart environments

Nowadays, the Internet of Things (IoT) is becoming progressively colloquial to media. However, when there are trillions of resources out there, how can we spontaneously specify the resource we need? Therefore, one of the main research questions is the device and service discovery. Many standard web services descriptions are used to describe not only web services but also physical devices. These devices are encapsulated under the web service communication layer to make them available on the Internet. This technique enables automatic discovery, configuration, and execution of resources in dynamic environments. Thus, we focus on the resource description language that allows semantic annotation. Nevertheless, there is no single standard formalism to describe resources. It is more tactful to handle multiple description formalisms simultaneously. This thesis presents a cross-formalism resource discovery technique which utilizes the user context and resources context to improve the recommendation of resources. The discovery process should not be restricted to single resource description formalism. Moreover, the matching algorithm should be user-aware and environmentally adaptive, i.e. depending on the users current situation, rather than limit to keyword-based search. This thesis explains the implementation detail and shows the evaluation of each implemented module. We aimed to prove that the quality of the result is improved significantly compared to conventional discovery techniques. To demonstrate the usability of the proposed method, we deploy it in MERCURY. MERCURY is a platform that allows both businesses to engage with their customers and end users to create custom-made applications. Within the context of MERCURY, registration, assembling, and execution of resources need the automatic resource discovery. Since the implementation of this work is designed to be a standalone service, there is no restriction to use it under the domain of MERCURY