On the Suitability of Estelle for Multimedia Systems

Formal Description Techniques have been widely used for the specification of traditional networked applications. They have not been applied to the specification of new applications such as multimedia systems yet. In this paper, we examine the FDT Estelle with respect to its suitability for multimedia system specification and automatic derivation of efficient implementations. We show that it is possible to specify certain aspects of multimedia systems, but that Estelle is not sufficient for others. The derived implementations often perform badly. We show the reasons and propose to use a slightly modified Estelle syntax and semantics to solve the problems. The implemented solution was tested successfully

On the Influence of Semantic Constraints on the Code Generation from Estelle Specifications

Implementations automatically derived from formal descriptions often do not fulfill the performance requirements of real-life applications. There are several reasons for this. In the paper, we address two of these issues for the FDT Estelle. The first issue has to do with the impact of the Estelle semantics on the code generation. We show that a performance gain can be achieved, if the module attributes are applied with care. The second issue relates to the implementation model applied for the automatic code generation. We discuss how the activity thread model, a technique known from manual protocol implementation, can be applied to automatically derive efficient implementations from Estelle specifications. The activity thread model reduces the overhead for process and memory management. In the paper, we analyze the prerequisites to apply the model and present measurements comparing the performance achievable with the technique. The measurements are given for different implementations of XTP and the XDT protocol

Efficient Configuration of Protocol Software for Multiprocessors

Efficient implementation of communication software is of crucial importance for highspeed networks. One way to improve the runtime performance of protocol implementations in the network nodes is the use of parallelism. Formal description techniques like Estelle improve the specification process in many respects and allow for semiautomatic code generation. Therefore, they are now widely accepted. We present a code generator for Estelle that compiles and automatically configures protocol software for a multiprocessor. Software modules are distributed over the available processors and executed concurrently. We report performance results on a KSR1 with 28 available processors under the OSF/1 operating system

Fibrodisplasia ossificante progressiva

Fibrodisplasia (miosite) ossificante progressiva (FOP) é doença rara, de herança autossômica dominante, na qual ocorre ossificação ectópica progressiva e malformação esquelética, principalmente no tecido conectivo dos músculos. O diagnóstico é baseado nos achados clínicos e demonstração radiologica das malformações esqueléticas. Relatamos o caso de uma menina de 5 anos de idade com FOP