Abstract: Digital reference service is when a traditional library
reference service is provided electronically. In most cases users do
not get full satisfaction from using digital reference service due to
variety of reasons. This paper discusses the formal specification of
web services applications for digital reference services (WSDRS).
WSDRS is an informal model that claims to reduce the problems of
digital reference services in libraries. It uses web services technology
to provide efficient digital way of satisfying users’ need in the
reference section of libraries. Informal model is in natural language
which is inconsistent and ambiguous that may cause difficulties to the
developers of the system. In order to solve this problem we decided
to convert the informal specifications into formal specifications. This
is supposed to reduce the overall development time and cost. We use
Z language to develop the formal model and verify it with Z/EVES
theorem prover tool.
Abstract: Unified Modelling Language (UML) is a software modelling language that is widely used and accepted. One significant drawback, of which, is that the language lacks formality. This makes carrying out any type of rigorous analysis difficult process. Many researchers attempt to introduce their approaches to formalise UML diagrams. However, it is always hard to decide what language and/or approach to use. Therefore, in this paper, we highlight some of the advantages and disadvantages of number of those approaches. We also try to compare different counterpart approaches. In addition, we draw some guidelines to help in choosing the suitable approach. Special concern is given to the formalisation of the static aspects of UML shown is class diagrams.
Abstract: Due to important issues, such as deadlock, starvation,
communication, non-deterministic behavior and synchronization,
concurrent systems are very complex, sensitive, and error-prone.
Thus ensuring reliability and accuracy of these systems is very
essential. Therefore, there has been a big interest in the formal
specification of concurrent programs in recent years. Nevertheless,
some features of concurrent systems, such as dynamic process
creation, scheduling and starvation have not been specified formally
yet. Also, some other features have been specified partially and/or
have been described using a combination of several different
formalisms and methods whose integration needs too much effort. In
other words, a comprehensive and integrated specification that could
cover all aspects of concurrent systems has not been provided yet.
Thus, this paper makes two major contributions: firstly, it provides a
comprehensive formal framework to specify all well-known features
of concurrent systems. Secondly, it provides an integrated
specification of these features by using just a single formal notation,
i.e., the Z language.