Object-Oriented Modeling and Design Using DELTA, an Incremental Design Language.

Object-oriented technology has opened the doors for many new ideas in system development. The object-oriented paradigm has produced many new object-oriented programming languages. As with any new methodology, a need for formalism arises to remove ambiguities and inconsistencies and to bring a sense of continuity to software design. Formal languages provide a sound basis for software development throughout the software life cycle. This work presents a set of characteristic features for object-oriented design languages and defines a formal object-oriented design language, DELTA. The rapidly changing face of software has led to an ever increasing need to update out-of-date methods and user interfaces. Software developers want to be able to use the same type of visual interfaces available in application software. The introduction of windowing environments has led to a market for methodologies which incorporate graphical features to supplement textual components of software. The present genre of formal languages must evolve in the same direction to be considered as effective in the design process. DELTA meets this need by providing a modern development environment with graphical features to complement the text that is necessary in any design specification. Researchers and prominent software engineers have provided a litany of object-oriented methodologies. The commonality of these methods is the step-by-step approach to software development. Software engineers agree in theory that the best approach to designing software which will stand the test of time is one which has a sound established discipline. Such a discipline produces a design in incrementations. DELTA supports this theory by providing established levels of incremental design representation. The advent of computer-aided design has led to the evolution of rapid-prototyping. Changes in system requirements, detection of errors, competition in the market, and the ongoing maintenance of software systems can be addressed by the development of system prototypes. DELTA responds to this challenge by establishing a design specification representation which can be easily mapped to an object-oriented programming language. This transition from design to prototype can be enhanced by formal annotations to the chosen implementation language. Annotations have been developed for DELTA software designs prototyped in the object-oriented language Actor

An object-oriented component-based approach to building real-time software systems

A project report submitted to the Faculty of Erlglncerlng, University of Witwatersrand, Johannesburg, In partial fulfilment of the requirements for the degree of Master of Science In Engineering Johannesburg 1993This Project Repolt r ''"lorts on the study of an approach to building integrated real-time software systems based on re-usable object-oriented components. The basis of the approach is the development of a a-layered structure of components, where each layer is built on the underlying layer of components, The lower layer of components consists of generic re-usable building blocks that may be re-used for building and integrating other real-time applications. The middle layer consists of components that are generic to the application domain, and the top layer consists of components that are specific to each application of that application domain. The Report includes researching and developing methods of communicating between these building blocks using an OSI/CMIP-conformant 'software highway" and in this regard particular attention is given to the formal and de facto industry standards. With this approach, it is argued that the application engineer can effectively build new applications using the re-usable components. This is demonstrated by reporting on the implementation of a large real-world Telecommunications Network Management application. The Project Report contains a critical analysis of the technical, organisational and project management issues of this Object-oriented component approach as compared to the traditional development approach. The Report concludes that despite certain technical and organisational concerns, the object-oriented approach does indeed yield several worthwhile benefits for developing real-time software systems. These benefits include genuine re-usability, and l"1proved productivity, testability and maintainability

A Knowledge-based approach to understanding natural language

Understanding a natural language requires knowledge about that language as a system of representation. Further, when the task is one of understanding an extended discourse, world knowledge is also required. This thesis explores some of the issues involved in representing both kinds of knowledge, and also makes an effort to arrive at some under standing of the relationship between the two. A part of this exploration involves an examination of some natural language understanding systems which have attempted to deal with extended discourse both in the form of stories and in the form of dialogues. The systems exam ined are heavily dependent on world knowledge. Another part of this exploration is an effort to build a dialogue system based on speech acts and practical argu ments, as they are described in Recognizing Promises, Advice, Threats, and Warnings , a Masters Thesis presented to Rochester Institute of Technology, School of Computer Science and Technology, in 1986 by Kevin Donaghy. This dialogue system includes a deterministic syntactic parser, a semantic representation based on the idea of case frames, and a context interpreter that recognizes and represents groups of sentences as practical arguments. This Prolog implementation employs a frame package developed and described in A Frame Virtual Machine in C-Prolog , a Masters Thesis presented to Rochester Institute of Technology, School of Computer Science and Technology, in 1987 by LeMora Hiss. While this automated dialogue system is necessarily limited in the domain that it recognizes, the opportunity it allows to build a mechanism and a system of representation brings with it a range of issues from the syntactic, through the semantic, to the contextual and the pragmatic. Here, the focus of inquiry came to settle in the semantic representa tion, where the relationship between knowledge about language and knowledge about the world seems to be naturally resident

Model of Classroom Learning for Eighth Grade and High School Students Based on the Relationship Between Student Ability, Perceived Classroom Climate and Their Interaction

The study was to determine relationships between general ability (A), classroom averages of classroom environment (CE), and classroom learning (CL) and retention (Rtn) of eighth grade and high school students (S). A model of CL was proposed to investigate this problem. CL = f(A) + f(CE) + f(A X CE). This model was tested for two groups using analysis of partial variance (APV): an experimental group (E), and a control group (R). Both groups were taught the same unit of instruction (T). Focus was on representativeness of instructional treatment (T) - external validity, while maintaining internal validity. The T that S received was an average of 11.0 days of instruction on acid-base theory. Teachers (Trs) were instructed to teach using normal methods and materials. S taught by different Trs received different amounts and types of instruction. These differences were controlled by APV. Nine Trs volunteered. Trs were assigned to E and R. Trs taught 27 classes containing 541 S (375 high school and 166 eighth grade). Trs selected a unit on acid-base theory as the T. Sixteen independent variables (IV) were collected three weeks before T began. Trs administered three A tests (Cattell's Culture Fair Test: 4 scales), and a vocabulary (2 scales) and an induction test (I-1) (from Kit of Factor References Tests). Next, Trs administered the Classroom Environment Scale (CES: 9 scales). Two unit tests (UT) were designed by the author measuring CL and Rtn. A UT was administered to R as a pretest on the first day of T. AUT was administered to both the E and the R on the last day of the T. The T took 11.0 class periods to complete. After 15.3 days of the posttest, a UT was given to the E to measure Rtn. The 15 IV .were reduced to 5 factors (F) by a likelihood factor analysis and varimax rotation. Two A Fs were named verbal and nonverbal ability; three CE Fs were named: student centered environments (Env), high structure Env, and high discipline Env. The A set accounted for 13.8% (E) and 17.6% (R) of the covariate (COV) adjusted (Ad) CL variance (V). The CE set accounted for 8.5% (E) and 5.3% (R) of the Cov Ad Cl V. The (Grade level X CE) set accounted for 0.0% (E) and 4.5% (R) of the Cov Ad Cl V. The A set accounted for 11.8% (E) of the Cov Ad retention V. The CE set accounted for 13.6% of the Cov Ad Rtn V. The (A X CE) set accounted for 8.3% (E) of the Cov Ad Rtn V, and the (Grade level X CE) set accounted for 0.1% (E) of the Cov Ad Rtn V. The best model of Cl and Rtn only contained an A and a CE set. This model accounted for 23.6% (E), and 22.2% (R) of the Cov Ad Cl V, and 23.7% (E) of the Cov Ad Rtn V. There is a great deal of room for improvement. This model accounted for 45.8% (E) and 60.0% (R) of the total CL V, and 36.2% of the total Rtn V.Educational Psycholog

Bowdoin Orient v.91, no.1-19 (1961-1962)

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