Based on the increasing complexity of modern avionics, the associated system design processes moved towards Model Driven Architecture (MDA) based processes. Additionally, the demand for higher system autonomy features requires means to further modularise mission systems and to define and establish interactions among the systems’ individual components. Therefore, the ideas of service-oriented computing are currently adapted to established, model driven design processes. With respect to modelling interactions for service components, current approaches are limited to only a fixed set of communication primitives, restricting a service designer’s expressiveness to specify service interaction. In consequence, interaction patterns not included in this basic set have to be reflected in application code, mangling application and communication logic. Furthermore, when service functionality relies on communication semantics which are not provided by the underlying set of primitives, additional emulation behaviour has to be added to the service which makes this mangling even worse. Platform independence is reduced as services can not easily be ported to platforms not natively supporting the selected primitives which contradicts the ideas of model-driven development. Addressing these limitations, this thesis proposes a new model-driven service development process based on Interaction Templates (ITs), promoting interactions among service participants to first class modelling entities. The process focuses on modelling the interactions among service participants. Interaction semantics are explicitly specified in models, beyond pure stereotyping, and gain increased platform independence for services with respect to communication. The process exploits automated Model-to-Model (M2M) and Model-to-Text (M2T) transformations to assist service implementation and to automatically derive interaction realisations on concrete target platforms. This allows for easy replacement and inter-mixing of communication middleware to realise a service’s interactions. This way, services become independent of the underlying communication primitives by only relying on ITs and not platform primitives which are hidden behind ITs. In turn, realising ITs on concrete platforms is not affected by their utilisation for service interaction. Beside the novel modelling process itself, the presented work defines a Unified Modeling Language (UML) profile, referred to as UML Profile for Interaction-centric Services (UP4IS), which directly supports the adaptation of standard UML language constructs and tools for the proposed modelling approach. The whole development process is demonstrated via the specification of a simple video recording systems consisting of two services. The services themselves are based on a representative IT library which forms an essential part of the presented case study. Using these service and IT models, the thesis emphasises the necessary model transformation and code generation steps to derive service implementations based on the abstract models.

Der 39. Band der Leipziger Beiträge zur Informatik setzt sich mit den Herausforderungen im Zusammenhang mit der zunehmenden Industrialisierung der Dienstleistungswirtschaft auseinander. Eine hohe Komplexität der Dienstleistungsportfolios sowie eine zunehmende Dienstleistungsorientierung ehemals rein produktionswirtschaftlich ausgerichteter Unternehmen bedürfen leistungsfähiger und angepasster Methoden und Werkzeuge. Voraussetzung dafür ist die präzise und umfassende Modellierung von Dienstleistungen, die Berücksichtigung von Aspekten der Produktivität sowie die Entwicklung geeigneter Softwarewerkzeuge. Das vorliegende Buch beschäftigt sich mit diesen Herausforderungen und Fragestellungen und schlägt verschiedene Lösungsansätze vor.

Denial-of-service attacks (DoS) and distributed denial-of-service attacks (DDoS) attempt to temporarily disrupt users or computer resources to cause service un- availability to legitimate users in the internetworking system. The most common type of DoS attack occurs when adversaries °ood a large amount of bogus data to interfere or disrupt the service on the server. The attack can be either a single-source attack, which originates at only one host, or a multi-source attack, in which multiple hosts coordinate to °ood a large number of packets to the server. Cryptographic mechanisms in authentication schemes are an example ap- proach to help the server to validate malicious tra±c. Since authentication in key establishment protocols requires the veri¯er to spend some resources before successfully detecting the bogus messages, adversaries might be able to exploit this °aw to mount an attack to overwhelm the server resources. The attacker is able to perform this kind of attack because many key establishment protocols incorporate strong authentication at the beginning phase before they can iden- tify the attacks. This is an example of DoS threats in most key establishment protocols because they have been implemented to support con¯dentiality and data integrity, but do not carefully consider other security objectives, such as availability. The main objective of this research is to design denial-of-service resistant mechanisms in key establishment protocols. In particular, we focus on the design of cryptographic protocols related to key establishment protocols that implement client puzzles to protect the server against resource exhaustion attacks. Another objective is to extend formal analysis techniques to include DoS- resistance. Basically, the formal analysis approach is used not only to analyse and verify the security of a cryptographic scheme carefully but also to help in the design stage of new protocols with a high level of security guarantee. In this research, we focus on an analysis technique of Meadows' cost-based framework, and we implement DoS-resistant model using Coloured Petri Nets. Meadows' cost-based framework is directly proposed to assess denial-of-service vulnerabil- ities in the cryptographic protocols using mathematical proof, while Coloured Petri Nets is used to model and verify the communication protocols using inter- active simulations. In addition, Coloured Petri Nets are able to help the protocol designer to clarify and reduce some inconsistency of the protocol speci¯cation. Therefore, the second objective of this research is to explore vulnerabilities in existing DoS-resistant protocols, as well as extend a formal analysis approach to our new framework for improving DoS-resistance and evaluating the performance of the new proposed mechanism. In summary, the speci¯c outcomes of this research include following results; 1. A taxonomy of denial-of-service resistant strategies and techniques used in key establishment protocols; 2. A critical analysis of existing DoS-resistant key exchange and key estab- lishment protocols; 3. An implementation of Meadows's cost-based framework using Coloured Petri Nets for modelling and evaluating DoS-resistant protocols; and 4. A development of new e±cient and practical DoS-resistant mechanisms to improve the resistance to denial-of-service attacks in key establishment protocols.

Based on the increasing complexity of modern avionics, the associated system design processes moved towards Model Driven Architecture (MDA) based processes. Additionally, the demand for higher system autonomy features requires means to further modularise mission systems and to define and establish interactions among the systems’ individual components. Therefore, the ideas of service-oriented computing are currently adapted to established, model driven design processes. With respect to modelling interactions for service components, current approaches are limited to only a fixed set of communication primitives, restricting a service designer’s expressiveness to specify service interaction. In consequence, interaction patterns not included in this basic set have to be reflected in application code, mangling application and communication logic. Furthermore, when service functionality relies on communication semantics which are not provided by the underlying set of primitives, additional emulation behaviour has to be added to the service which makes this mangling even worse. Platform independence is reduced as services can not easily be ported to platforms not natively supporting the selected primitives which contradicts the ideas of model-driven development. Addressing these limitations, this thesis proposes a new model-driven service development process based on Interaction Templates (ITs), promoting interactions among service participants to first class modelling entities. The process focuses on modelling the interactions among service participants. Interaction semantics are explicitly specified in models, beyond pure stereotyping, and gain increased platform independence for services with respect to communication. The process exploits automated Model-to-Model (M2M) and Model-to-Text (M2T) transformations to assist service implementation and to automatically derive interaction realisations on concrete target platforms. This allows for easy replacement and inter-mixing of communication middleware to realise a service’s interactions. This way, services become independent of the underlying communication primitives by only relying on ITs and not platform primitives which are hidden behind ITs. In turn, realising ITs on concrete platforms is not affected by their utilisation for service interaction. Beside the novel modelling process itself, the presented work defines a Unified Modeling Language (UML) profile, referred to as UML Profile for Interaction-centric Services (UP4IS), which directly supports the adaptation of standard UML language constructs and tools for the proposed modelling approach. The whole development process is demonstrated via the specification of a simple video recording systems consisting of two services. The services themselves are based on a representative IT library which forms an essential part of the presented case study. Using these service and IT models, the thesis emphasises the necessary model transformation and code generation steps to derive service implementations based on the abstract models.

Der 39. Band der Leipziger Beiträge zur Informatik setzt sich mit den Herausforderungen im Zusammenhang mit der zunehmenden Industrialisierung der Dienstleistungswirtschaft auseinander. Eine hohe Komplexität der Dienstleistungsportfolios sowie eine zunehmende Dienstleistungsorientierung ehemals rein produktionswirtschaftlich ausgerichteter Unternehmen bedürfen leistungsfähiger und angepasster Methoden und Werkzeuge. Voraussetzung dafür ist die präzise und umfassende Modellierung von Dienstleistungen, die Berücksichtigung von Aspekten der Produktivität sowie die Entwicklung geeigneter Softwarewerkzeuge. Das vorliegende Buch beschäftigt sich mit diesen Herausforderungen und Fragestellungen und schlägt verschiedene Lösungsansätze vor.:Stephan Klingner Produktivitätssteigerung durch komponentenbasierte Dienstleistungen – Ergebnisse eines Forschungsprojekts Thomas Meiren, Sabrina Lamberth Beschreibung und Strukturierung von Dienstleistungsan geboten Sabrina Lamberth Dienstleistungsproduktivität – Grundlagen und Kennzahlen für die komponentenbasierte Produktivitätsbetrachtung von Dienstleistungen. Stephan Klingner, Martin Böttcher Der Begriff der Komponente als Grundlage von Konfigurationen in der Dienstleistungsdomäne Michael Becker, Stephan Klingner Metamodell zur komponentenbasierten Modellierung komplexer Dienstleistungen. Michael Becker, Stephan Klingner Abhängigkeitsbeziehungen zwischen Elementen von Dienstleistungsportfolios Michael Becker, Stephan Klingner, Frank Schumacher Werkzeug zur komponentenbasierten Modellierung und Konfiguration von Dienstleistungen Sabrina Lamberth, Thomas Meiren Methodik zur produktivitätsorientierten Granularitätsoptimierung bei komponentenbasierten Dienstleistungen Sabrina Lamberth Methodik zur Analyse und Optimierung der Dienstleistungsproduktivität unter Berücksichtigung qualitativer Faktoren Mike Freitag, Franz Pauthner, Stefan Ochs, Mathias Mayer Entwicklung eines Frameworks zum Change Management für ECM-Lösungen Ronni Swialkowski, Arndt Döhler Komponentisierung des Full-Services E-Commerce Angebots bei Intershop Till Post, Wilhelm Taurel Aus der Praxis der Produktivität internationaler Hightech-Dienstleistungssysteme