The design of correct software remains difficult, especially when dealing with concurrency. The primary goal of the research presented here is to devise a pragmatic software development method which  aids the software designer in producing reliable software,  is scalable,  is understandable,  follows a unified approach towards software development (is applicable to different implementation architectures),  promotes reuse,  has seamless transitions between the software development phases,  guarantees general availability and minimises developmental resources. The two main characteristics of the proposed new development method are captured in its name, viz. Single Location Object-Oriented Programming (SLOOP) . It is an object-oriented method, but its computational model is that of a set of statements that execute infinitely often and in any order. A program with such a computational model is called a Single Location Program (SLP). A UNITY program can also be classified as a Single Location Program. In the UNITY theory of programming it was demonstrated how this computational model could simplify correctness reasoning, particularly for concurrent systems. It is this simplification, together with the structuring and reuse features of object-orientation, that is leveraged in the SLOOP method to produce a mechanism whereby ordinary software practitioners can take advantage of the benefits of a more rigorous approach towards software development without requiring an in-depth understanding of the underlying mathematics. The following features of the SLOOP method contribute towards achieving the above goals:  its computational model (it simplifies correctness reasoning, thereby promoting understandability and scalability, and also facilitates designs that are independent of the target implementation architectures),  its object-oriented nature (apart from promoting reuse of frameworks, design patterns and classes, the SLOOP method provides the necessary mechanisms to facilitate reuse of correctness properties, correctness arguments as well as mappings to implementation architectures),  its emphasis on correctness reasoning throughout the software development life cycle (its "constructive approach" aids reliability and seamlessness),  the unique way in which the correctness properties can be specified, reused and reasoned about (this contributes towards understandability and scalability),  the checklist of useful correctness properties that is provided (this promotes reliability),  the incorporation of existing notations into the SLOOP syntax (this guarantees general availability, minimises developmental resources and aids understandability). The main contribution of this thesis is that it presents a unique way of incorporating the SLP computational model into an object-oriented method with the specific aim of simplifying informal correctness reasoning and promoting reuse. The notation used for the specification of correctness properties facilitates reuse of correctness properties, ensures the integrity of these specifications and allows one to specify correctness properties at a higher level of abstraction. The SLOOP method offers a unique way of modelling concurrency in object-oriented systems (via its parallel methods), which takes full advantage of the encapsulation and inheritance features of object-orientation. The issues surrounding mappings to implementation architectures are addressed, showing how even mappings can be reused. Finally, the general applicability of the SLOOP method is demonstrated. / Thesis (PhD (Computer Science))--University of Pretoria, 2007. / Computer Science / unrestricted

D.Phil. (Computer Science) / Please refer to full text to view abstract

see document / Master of Science

This research develops an object-oriented approach to model airport ground network traffic operations. A generic modeling library is developed as a tool kit to model the basic traffic operations in the airfield using an object-oriented approach. The proposed generic modeling library for airfield operations is a collection of predefined abstract components implemented in the Java object-oriented programming language. Classes are defined and used as the basic components in a variety of airfield operation modeling, simulations, and optimizations. The generic airport modeling framework consists of a set the components that are necessary for modeling the basic activities of airfield traffic operations. By using the multi-threading techniques, components are integrated into the proposed modeling framework. Unlike traditional sequential simulation model, this framework organizes simulation activities into four major groups which are: flight schedule, aircraft movement, time, and animation. Instead of using built-in control logic, the framework adapts an open system policy which gives the flexibility to the end users to incorporate the user-preferred control logic into the end models. Another purpose in this research is to provide a future mechanism to study airfield ground traffic automated control systems with Just-In-Time forecasting and model system performance in a real-time ATC environment. The proposed generic library could be implemented into a Internet/intranet ready application which can query real time information and provide real time advice to pilots and air traffic controllers. This study is one of a few current research projects that are of using multiple threading technique to study traffic operation problems. The proposed generic library is originally implemented with C++ and, in the final stage, with Java, a truly cross-platform object-oriented language. Application written in Java can run on most of the mainstream computer operating systems without modifications. Although the proposed library is for airfield traffic control system, it could also be extended into air traffic control system as well as advanced transportation system. / Ph. D.

Software measurement plays an important role in today's software development. Coupling is a measure used in software development that influences the understandability, maintainability and reusability of software components. Many proposals have been made for measuring object-oriented coupling of software components; however, most measures are not useful in the real world of software development. This paper provides a practical guide for evaluating coupling between object-oriented components. This technique is meant for use by software developers who are engaged in the development of software designed to be easy to understand and easy to maintain.

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Computers since their inception have been used to solve engineering problems. Toward support of next-generation, customizable, generalized software, a mathematical equation editor has been designed, developed, and tested using object oriented (OO) programming techniques. The motivating purpose of this equation editor is to allow a user to graphically define mathematical equations to be solved in a computational partial differential equation-based problem solving environment. The OO scripting language Python was used in conjunction with the OO GUI toolkit Qt to create the editor. Analysis of the underlying abstraction of a general equation yielded the key concept of an information-holding bounding box. Such boxes hierarchically contain every character and symbol in an equation. Specific rules were formulated to spatially arrange a set of boxes into a properly formatted equation. Robust insertion logic of alphanumeric characters, mathematical symbols, and common function names was implemented for intuitive point-and-click equation building.

This study evaluated habitat parameters for the red-cockaded woodpecker (RCW; Picoides borealis) on three tracts in Hoke County, North Carolina. Multi-spectral imagery was used to classify shadow, non-vegetation, herbaceous, hardwoods, and loblolly and longleaf pine trees. Field data were collected for image classification training and validation. Overall classification accuracy for separating hardwood from pine trees, was 80.8%. When separating longleaf (Pinus palustris Mill.) and loblolly (Pinus taeda L.) pine from hardwoods the accuracy was 73.7%. Field-based height/diameter relationships were applied to LiDAR-identified trees to predict diameter classes. Due to differences in management regimes and site conditions, each tract had different majority pine diameter classes. Average height, diameter, basal area, and stem density per plot were reported from matched, unmatched, and total LiDAR trees to field trees. Differences between the height, diameter, basal area, and stem density values occurred between the matched and unmatched LiDAR- and field-identified trees.

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