Olaf Drögehorn

Framework and Tool Support for Formal Verification of Highspeed Transfer Protocol Designs

Formal description techniques, verification methods, and their tool-based automated application meanwhile provide valuable support for the formal analysis of communication protocol designs. Nevertheless the practical analysis of modern protocols still requires relatively great efforts and therefore many protocol developments do not employ formal methods. In that context the transfer protocol framework aims to complementary support. It supplies a rich collection of specification modules and guides their efficient composition to service and protocol specifications. Moreover the functional relations between service properties and implementing protocol mechanisms have been investigated systematically. The framework provides a collection of corresponding theorems to be applied to protocol correctness proofs. In result protocol verification can be reduced to the selection, instantiation, and proper arrangement of framework theorems. The verification process can further be supported by special tool-assistance. The tool COAST identifies the compositional structure of a protocol specification mechanically and selects according framework theorems. It splits service property proofs into arrangements of subproofs where the subproofs can mainly be accomplished by application of the selected framework theorems. After outlining the general transfer protocol framework approach we concentrate on the introduction of the tool COAST. We describe its functions and clarify its application by means of the verification of the complex real-life high-speed data transfer protocol XTP.

Design Principles for Future Service Platforms

The vision of pervasive computing and communication will shape the individual life in the future. Following this vision, the goal for new business sectors will be to provide an easy way of creating and deploying different kind of service environments. This paper introduces briefly the problem of overall architectures for service execution environments and identifies an architectural approach, the requirements and design guidelines to built service execution environments and related platforms that are fully compatible to each other. The concepts presented in this paper have been developed by the Wireless World Research Forum (WWRF) Working Group 2 (WG2) and are under permanent discussion in this forum.

Framework for middleware in ubiquitous computing systems

Developing system software for ubiquitous computing makes consideration of numerous requirements necessary. This is primarily due to the dynamic, mobile, unpredictable and heterogeneous environment of ubiquitous computing systems. Middleware provide solutions to common tasks in ubiquitous computing, e.g. communication, discovery, deployment, personalisation, group management etc. Middleware are developed using frameworks. Existing frameworks such as CORBA component model, Webservices, and Jini support middleware in certain aspects, e.g. communication protocols, but restrict them to certain assumptions, e.g. no disconnected operation or the client/server model. In this paper a framework for middleware in ubiquitous computing is presented. The framework is used to develop middleware with the service oriented architecture paradigm. The framework presented is applied to a middleware to allow for group based communication. The middleware, and especially the management entity of the middleware, is described in greater detail in this paper

Design Principles and Requirements of Future Service Platforms

The vision of pervasive computing and communication will have an important impact on our lives. Following this vision, the goal for new business sectors will be to provide an easy way of creating and deploying different kinds of service environments. This paper introduces the requirements on and the problem of overall architectures for service execution environments and identifies an architectural approach, the requirements and design guidelines to built service execution environments and related platforms that are fully compatible to each other. The concepts presented in this paper have been developed by the Wireless World Research Forum (WWRF) Working Group 2 (WG2) and are under ongoing discussion.

Context awareness in I-centric systems - Dynamic Context Learning Using a Rule-Based Approach -

Capturing contextual information, especially higher-level contexts, enables systems to understand and predict the behaviour of a mobile user. This kind of information is mostly implicit, abstracting a complex state of a situation, and can only partly be captured by sensors. Higher-level context has the potential to make user applications simpler and more intuitive. However, composing higher-level contexts from explicit, atomic contexts requires complex procedures to be used and uncertainty due to inconsistent sensor readings and incomplete information to be reduced. In this paper, we introduce a new approach that assists application developers to take higher-level contexts into account without the need to know the details of atomic contexts. To demonstrate our approach, we will introduce the Context-Aware E-Pad (CAEP) we have designed and implemented.

Formal specification and verification of transfer-protocols for system-design in VHDL

In order to meet the requirements of upcoming multimedia applications new transfer-protocols have to be developed. But the design of new protocols is highly complex so the support of design-strategies by formal methods is recommended. On base of today’s mostly informal, incomplete, and ambiguous protocol descriptions correctness-proofs cannot be performed. In order to realize a new protocol an implementation in hard- or software has to be designed. The recent way to implement hardware-devices is a description in a hardware description language like VHDL or Verilog. In this contribution we will outline a compositional specification-style using a simple temporal logic of actions, TLA. Based on this description we are able to prove the protocol against a service description by using boolean logic. Corresponding to the TLA-specification we will introduce a VHDL-near dialect of TLA, the translation rules, and the mechanisms which will be needed to transform TLA into VHDL.

An architectural approach for building platforms is still needed

The vision of pervasive computing and communication will shape individual life in the future. Following this vision, the goal for new business sectors will be to provide an easy way of creating and deploying different kinds of service environments. This paper introduces briefly the problem of overall architectures for service execution environments and identifies an architectural approach, the requirements and design guidelines to built service execution environments and related platforms that are fully compatible with each other.