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No description available.

No description available.

No description available.

Researchers in the Forms/3 group have previously developed the WYSIWYT methodology, exploring a way of systematically testing spreadsheet languages. The previous work presented the WYSIWYT methodology for individual spreadsheet cells, and later partially extended it to large grids in which some cells share the same formula. The Forms/3 spreadsheet language supports not only operations of individual cells but also some advanced programming features such as homogeneous grids, recursive programs, and user-defined abstract data types. Therefore, it is important for the testing methodology to support even these more powerful features of the language, not just the "easy parts". In this document, we present extensions to the WYSIWYT methodology for these advanced features. We optimized the visual aspects of testing spreadsheet grids and collected experimental information about scalability. We also developed two possible ways the WYSIWYT methodology could be extended to accommodate recursion in terms of their testing theoretic aspects, implementation strategies, algorithms and time complexities. Since the ultimate goal is to help the people using these languages, we also conducted an empirical study and used its results to inform our choice as to which of these two approaches to adopt. Finally, we developed an approach of testing user-defined abstract data types; here we present design, implementation issues, algorithms and time complexities. / Graduation date: 2002

Emulation is defined as an intermediate stage of simulation where the model represents the "as specified" mechanical plant and equipment, but not the control logic required to drive it. This thesis investigates the utility of providing a computer representation of the functional elements to be controlled by system control programs. These representations or "emulators" mimic the behavior of the system, or factory being controlled. The advantages of such a scheme are that developers of control software, are able to test out new control methodologies without actually connecting to the hardware system under control. This thesis investigates system control for automated manufacturing systems and identifies how emulation can be used as a valid tool in reducing the implementation time of such systems. The functions and characteristics of system control are identified as well as the problems associated with their implementation. The problems are then categorized to identify where emulation is a valid tool for problem resolution. This thesis is concluded by a description of a software demonstration which validated the concept of using emulation to solve system control problems. / Master of Science

This research explores the concepts of defensive programming as currently defined in the literature. Then these concepts are extended and more explicitly defined. The relationship between defensive programming, as presented in this research, and current programming practices is discussed and several benefits are observed. Defensive programming appears to benefit the entire software life cycle. Four identifiable phases of the software development process are defined, and the relationship between these four phases and defensive programming is shown. In this research, defensive programming is defined as writing programs in such a way that during execution the program itself produces communication allowing the programmer and the user to observe its dynamic states accurately and critically. To accomplish this end, the use of defensive programming snap shots is presented as a software development tool.

Call number: LD2668 .T4 1986 M67 / Master of Science / Computing and Information Sciences

Symbolic execution is a powerful technique used to perform various activities such as program testing, formal verification of programs, etc. However, symbolic execution does not deal with indexed variables in an adequate manner. Integration of indexed variables such as arrays into symbolic execution would increase the generality of this technique. We present an original substitution technique that produces array-term-free constraints as a counterargument to the commonly accepted belief that symbolic execution cannot handle arrays. The substitution technique deals with constraints involving array terms with a single aggregate name, array terms with multiple aggregate names, and nested array terms. Our approach to solving constraints involving array terms is based on the analysis of the relationship between the array subscripts. Dataflow dependence analysis of programs involving indexed variables suffers from problems of undecidability. We propose a separation technique in which the array subscript constraints are separated from the loop path constraints. The separation technique suggests that the problem of establishing data dependencies is not as hard as the general loop problem. In this respect, we present a new general heuristic program analysis technique which is used to preserve the properties of the relations between program variables.