We have obtained low resolution (∼20 Å FWHM) slit spectra of 10 quasar candidates located within one degree of the z = 2.181 quasar Q0122−380 with the objective of searching for signs of large scale structure matching the intervening rich absorption complexes seen over the redshift range 1.81 <∼ z <∼ 1.97 toward this object. Of the 8 confirmed quasars, 4 turn out to have redshifts z < 1.8, plac...

We present a new formal OO method, called FOX , which is a synergetic combination of the semi-formal Fusion method and the formal specification language Object-Z. To manage complexity and to foster separation of concerns, FOX distinguishes between analysis and design. In each phase structure and behaviour specifications are developed step-by-step. The specifications may be graphical or textual....

syntax static semantics dynamic semantics UML approach class diagrams OCL natural language Object-Z approach Object-Z class specs Object-Z predicates Object-Z operation & class diagrams in class specs specs Figure 4: Comparison of UML and Object-Z approach entities. We use Object-Z as a single formalism for the abstract syntax, the static semantics and the dynamic semantics. 1.5 Comparison to t...

ed timed models with multiple clocks but with well-developed tool support. Thus, it is of great interest and importance to investigate the possible links between OZ/TCOZ and TA so that they can be utilized coherently for building and verifying models of complex real-time systems in the development process. The objective of this thesis is to construct a unified framework for using OZ/TCOZ and TA...

Inasmuch as formal methods have continued to gain popularity within the industrial community, they are still far from attaining widespread acceptance, especially within the information systems domain. Reasons range from lack of appropriate education and training to lack of tools that provide continuity by integrating formal techniques with more traditional methods that may be more familiar for ...

FOOM (Formal Object-Oriented Methodology) is an information systems acquisition/development method which assists in understanding and modelling organizational and inter-organizational systems. The method promotes highly appropriate and precise requirements specifications for both interand intra-organizational information systems. We describe, in outline, FOOM (which has been under development s...

FOOM (Formal Object-OrientedMethodology) is an information systems acquisition/development method which assists in understanding and modelling organisational and inter-organisational systems. The method promotes highly appropriate and precise requirements speci cations for both interand intra-organisational information systems. In this paper, we describe, in outline, FOOM (which has been under ...

RATIONALE AND OBJECTIVES To evaluate the potential of high-pitch, dual-source computed tomography (DSCT) for compensation of motion artifacts. MATERIALS AND METHODS Motion artifacts were created using a moving chest/cardiac phantom with integrated stents at different velocities (from 0 to 4-6 cm/s) parallel (z direction), transverse (x direction), and diagonal (x and z direction combined) to ...

In this paper we develop a framework for semi-automated generation of test cases for object oriented programs from formal speci-cations. We use Object-Z as the formal speciication language. We have designed and prototyped a test system called OZTEST. It understands the characteristics of object-oriented speciications including inheritance. OZTEST maps the speciication to a corresponding impleme...

Software development process is on the basis of two important steps each of which has to be taken seriously, system requirement analysis and system modeling. There have been many different approaches in the literature that has their own strengths and weaknesses to tackle these two important steps, however, there is none comprehensive approach. Among them, formal methods by using their mathemati...