While interactive design tools, rapid prototyping tools, and user interface management systems (UIMSs) are advancing as cost-effective ways of producing interfaces, attention to usability is rarely incorporated into such tools. The advancement of producing interfaces more rapidly without addressing their quality is of limited worth. This thesis reports on the design and prototype implementation of a software tool, IDEAL (Interface Design Environment and Analysis Lattice), that encourages and enables user-centered design as an integral part of the user interface development process. IDEAL integrates usability engineering techniques and behavioral task representations with a graphical hierarchy of associated user tasks to support formative evaluation of an evolving user interface. IDEAL supplements the functionality of current interface construction tools by focusing on usability through user-centered design. IDEAL was designed and developed using the techniques it supports: formative evaluation and iterative refinement. Representative users participated in two phases of qualitative formative evaluations from which critical incidents, verbal protocol, and qualitative data were collected. Feedback from each phase contributed to the revised design of IDEAL. This empirical evaluation showed IDEAL to be useful as an automated tool for managing the interrelated tasks of interface development, including design, usability specification definition, and formative evaluation, that are currently performed manually (e.g., using pencil and paper.) / Master of Science

Prolog is a logic programming language based on first order logic. It uses resolution as a rule of inference, and unification is the heart of resolution. The unification algorithm is a syntactic process and hence attaches no meaning to function and predicate symbols. We incorporate arithmetic into unification by simultaneously solving linear equations that are created during the unification of partially instantiated numeric expressions. Prolog operates on the Herbrand universe, which is a single unstructured domain. In case of large structured domains, the number of resolution steps required for inference is large. We have incorporated type inheritance into Prolog to exploit large structured domains. Types are subuniverses corresponding to sets of objects. The subset of relation between types induces a hierarchy on the universe. Using the property of inheritance it is possible to obtain shorter proofs in inference. We used the constraint satisfaction model and the hierarchical constraint satisfaction concept to incorporate these extensions to Prolog. Thus, we succeeded in obtaining a logic programming language with arithmetic and type inheritance. This implementation extends standard Prolog and can be directly added to the WAM concept. / Master of Science

Prolog is a linear resolution theorem prover with restrictions on the form of the clauses to prune the search space. Although Prolog has been widely used for implementing natural language systems, database systems, knowledge based expert systems and other A.I tasks, it has many limitations. The inferencing is symbolic and all the computations are performed in the Herbrand universe. Prolog has no notion of function evaluation. The uniform parameter passing mechanism, viz unification, is syntactic and too restrictive in nature. Moreover, Prolog uses a depth first search strategy combined with chronological backtracking which renders the SLD-Resolution incomplete. In this thesis, we study the incorporation of a constraints solver into Prolog. The generalization of unification into a constraints satisfaction algorithm allows the incorporation of function evaluation into unification. Constraint satisfaction is used to replace unification thus enhancing the power of Prolog. This idea could possibly be extended to other contexts where unification is used. Constraints can also appear as goals in the body of a rule. We discuss the enhancement in expressive power leading to an efficient solution of a larger class of problems. We also discuss ways of compiling the constraint solver and the modifications that are needed to be made in the Warren abstract machine for Prolog. An interpreter for the extended Prolog (written in Prolog) incorporating a constraint solver is presented along with examples illustrating its power. / Master of Science

Turbo Pascal, a compiler for the personal computer, was investigated to determine if it is compatible with the calculations required by Structural engineers. The compiler was evaluated for calculation intensive programming as well as programming for data manipulation. A processor and a preprocessor for a plane frame program were used because they test the power of the language for calculations and they require the software to be user friendly and highly flexible with regard to manipulation of data. A description of the development and a user's guide to the programs are included. / M.S.

In this research, a C-Based Simulation Toolkit (CBST) was developed. It supports discrete, continuous, and combined simulation. CBST is a group of simulation support functions written in the language C. CBST functions are used within a specific framework similar to that of GASP IV. It employs the event scheduling world view for next event selection. The Runge-Kutta-Fehlberg integration method is used to update state variables. The simulation framework of CBST, descriptions of CBST functions, and details of program construction using CBST are described. Four models are developed using CBST and the results are analyzed. CBST is compared to similar software packages, namely GASP IV, DISC, and CSIM. CBST has more flexibility than GASP IV because it is C-based and because it offers resource management functions. CBST supports continuous and combined simulation, whereas DISC and CSIM do not. / Master of Science

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The WWW (World Wide Web) is a great place to share information - information can be shared across the entire world. By studying the characteristics of the WWW, we can make this information easier to find and access. Information on the web is accessed by use of web crawlers, like the search engine Google. A user types in what he/she is searching for and search results are displayed, where the user can click on a result and be taken to the corresponding website. In order for the search engine to come up with these results, algorithms must be created to search through the web and find websites relevant to the user's query. These algorithms must be quick, since web users often want information right away. They also must be accurate; A user does not want to have to weed through search results for what he/she wants; the user may get frustrated or lose interest. To create algorithms that are quick and that display accurate results, certain characteristics of the WWW must be discovered and considered. The web must be searched and the pages and hyperlinks must be stored to perform these algorithms and to discover these characteristics. The intention of this thesis is to present a library of functions in C++ for building and manipulating large graphs. These functions can be used to discover properties of graphs like degree distribution and diameter, which can be useful when studying graphs and subgraphs of the WWW.

Call number: LD2668 .T4 1985 W94 / Master of Science