Data Link Layer Designing Issues: Error ControlaA Roadmap

Different networks are used to transfer data from one device to another with acceptable accuracy. For most applications, a system must guarantee that the data received are identical to the data transmitted. Transmission media are most error-prone link. In a network, the capacity of nodes is different and the rate at which the sender is sending data might not be the same rate at which the receiver accepts it. In this paper, we discuss on designing issues of data link layer. The primary focus ison various error detecting and controlling mechanisms

An UML+Z Framework For Validating And Verifying the Static Aspect of Safety Critical System

AbstractThe aim of this paper is to propose an augmented framework for verifying and validating the static aspect of safety critical systems by analysing the UML class diagrams and the relationship between them. Since UML is a semi formal language which is provn to ambiguities due to its various graphical notations, hence Formal analysis of UML class diagram is required. Moreover, class diagram play an important role in system designing phase especially in safety critical systems. Any ambiguity or inconsistency in design can result in potential failure. Formal methods are the mathematical tools and methodology which are sandwiched at various stages of software development process to ensure the correctness, consistency and completeness of software artifacts such as requirement specifications, design etc. In this article, Z notation is used for the purpose of analysis formally and later on verified by the Z/EVES tool