Abstract 

Over the past few years, the subject of Intelligent Network (IN) has
captured the interest of the telecommunications community. The
objective of IN is to allow the introduction of new capabilities in the
telecommunications network and to facilitate and accelerate in a
cost-effective manner, service implementation and provisioning, in a
multivendor environment. However, this objective confronts a major
obstacle known as the feature interaction problem. The feature
interaction problem occurs when a feature is prevented from performing
its functionalities in the presence of other features.

In the first part of the thesis, we describe a LOTOS model for
structuring the Functional Entities (FEs) that are defined in the
Distributed Functional Plane (DFP) of the CS1 IN Conceptual Model
(INCM), and that are involved in the establishment of a call/connection
and invocation and processing of services. The specification of IN
services is achieved using Service Independent building Blocks (SIBs).
It is designed in a way that independent specification and rapid
introduction of services is provided.

In the second part of the thesis, a method for detecting feature
interactions between services is developed. The method is limited to
the detection of interactions caused by violation of features
properties. It is based on formalization of feature's properties,
derivation of goals satisfying the negation of these properties and use
of Goal Oriented Execution to detect traces satisfying these goals. A
trace satisfying a goal shows that an interaction exists between the
specified features by describing a scenario violating one of the
properties of the introduced features. 

It is concluded that LOTOS is useful as a Formal Description Technique
(FDT) in the Service Creation Environment (SCE). The developed
specification can be used for adding specifications of new services,
and for detecting interactions caused by violation of properties, if
there are any.