Test suites for database applications depend on adequate test data and real-world test faults for success. An automated tool is available that quantifies test data coverage for database queries written in SQL. An automated tool is also available that mimics real-world faults by mutating SQL, however tests have revealed that these simulated faults do not completely represent real-world faults. This paper demonstrates how half of the mutation operators used by the SQL mutation tool in real-world test suites generated significantly lower detection scores than those from research test suites. Three revised mutation operators are introduced that improve detection scores and contribute toward re-defining a sufficient set of mutation operators for SQL. Finally, a procedure is presented that reduces the test burden by automatically comparing SQL mutants with their original queries. / Master of Science

Typescript (photocopy). / Digitized by Kansas Correctional Industries

The concept of achieving low cost (≈ $20/m²) and ultra low weight (5 kg/m²) for heliostats is explored theoretically and experimentally. The objective of this work is to significantly improve the cost and performance of the structure under concern, without sacrificing strength and efficiency. The focus is on an innovative design of stretched-membrane heliostats. A reflective membrane of thin film is supported by a taut fishnet structural membrane consisting of graphite fiber-polymer matrix composite. The reflective and structural membranes are attached to a ring frame made of wood. The nonlinear problem of stress-strain analysis is formulated and solved using the finite-element code NASTRAN. The analysis is done for loads which include the initial stretching of the film and structural membrane and the pressure load due to wind. The scope of the present work is limited to analyzing the structural deformation behavior of flat-plate heliostats and partial extension to parabolic and semi-hemispherical dish reflectors.

An improved multi degree-of-freedom direct shear device has been designed and constructed to test interfaces and joints under pore water pressure. Any two structural (concrete, steel, wood) or geologic (soil, rock) materials may be tested in the device as long as the top specimen is solid. The apparatus is designed to hold a 7.5-inch diameter 3-inch thick upper sample and a 9-inch diameter 3-inch thick lower sample. A normal stress of 400 psi (2.7 MPa) and a shear stress of 550 psi (3.9 MPa) can be developed at the interface. Test loading may be static, quasi-static, or cyclic, and constant or variable stiffness loading is available. A stiff reaction frame was designed to house the device and is described. The electro-hydraulic system is capable of supporting cyclic testing at 30 Hz. A new computer-controlled data acquisition and control system is also described.

Phase shifting interferometry is one of the most promising methods for testing aspheres. However, one will encounter the following problems when it is applied to test an asphere: (1) very tight fringes produced by a strong asphere exceed the test system's resolution, (2) a test wavefront suffers from system aberrations of the interferometer that cause measurement errors, and (3) the wavefront immediately after reflection does not necessarily represent the shape of the test asphere. This thesis used a high density array sensor to detect the dense fringes. In order to solve the system aberration and the ray retrace problems, it is necessary to incorporate a ray trace code and phase shifting interferometry. This measurement principle was applied for an aspheric surface whose asphericity was 100 waves. A phase shifting Fizeau interferometer was incorporated with an optical design program. The attained accuracy was approximately one-tenth of a wave.

published_or_final_version / Civil Engineering / Doctoral / Doctor of Philosophy

published_or_final_version / abstract / Psychiatry / Master / Master of Philosophy

The effects of alignment and surface figure errors and their compensation with each other in optical systems are analyzed based on computer simulations with exact ray tracing data. These effects are included in the prediction of system performance and the testing of optics. Several simple systems are used as examples. In the prediction of system performance, a Ritchey-Chretian telescope and a Reflaxicon system are studied. A correct alignment can be found to compensate certain surface figure errors in the system. This will allow larger surface figure errors to be tolerated in the system. In the testing of optics, a method to separate the figure errors from the alignment error contributions is discussed and an off-axis test configuration, the Ritchey-Common test, is studied thoroughly. A figure design approach is suggested and compared with other approaches for reduction of the measured wavefront data in the Ritchey-Common test.

The dynamic response of subsurface cracks in fiber reinforced composites is analytically studied. The response of layered half-space and three-layered plate with two interface cracks excited by a plane SH-wave and line load respectively are studied by formulating the problem as integral equations in the frequency domain. The governing equations along with boundary, regularity and continuity conditions across the interface are reduced to a coupled set of singular integral equations by using Betti's reciprocal theorem along with the Green's functions. In addition, the transient response of an orthotropic half-space with a subsurface crack subjected to inplane line load at an arbitrary angle is analyzed. Two new Green's functions for the uncracked medium are developed and used along with the representation theorem to derive the scattered field. Satisfaction of the traction free condition at the crack surfaces gives rise to a system of singular integral equations. Singular integrals involved in the analysis are computed numerically by removing the poles. Part of the integrals containing the poles are then obtained analytically by using residue theorem. The solution of singular integral equations are obtained by expanding the unknown crack opening displacements (COD) in terms of a complete set of Chebychev polynomials. The problem is first solved in the frequency domain, the time histories are then obtained numerically by inverting the spectra via Fast Fourier Transform (FFT) routine. Numerical results are presented for isotropic and anisotropic materials for several different crack geometries. The results show significant influence of crack geometries and material properties on the COD and surface response of composites.

Both causal attributions and self-efficacy have been theorized as mediating performance on achievement tasks. However, few studies have explored the relationship between these constructs or in what way they may be affected by peer modeling. The purpose of this study was to explore developmental differences between two grade levels in the effect of modeling on persistence, self-efficacy judgments, and choice of attributions for predicted and actual outcomes on a figure-matching puzzle, and the relationship between self-efficacy and causal attributions. Seventy-three eighth graders and 73 third graders were randomly assigned to one of four experimental conditions or to a control condition. Four videotapes for each grade level, showing a male peer modeling either high or low persistence and success or failure on a figure-matching puzzle, constituted the experimental conditions. Subjects' attributions for various outcomes in achievement settings were recorded one week prior to the experimental session and at its conclusion, on the Intellectual Achievement Responsibility scale. Attributions for predicted and actual outcomes on a figure-matching puzzle were also recorded. Students' persistence on the nearly-impossible puzzle was measured by time in seconds, while an efficacy scale assessed their belief regarding their ability to solve the puzzle at three times during the experimental session. Significant differences were found between the grade levels for self-efficacy ratings, with third graders reporting greater efficacy beliefs than eighth graders. A significant change in self-efficacy ratings was also found, but it was not possible to determine which aspect of the experimental session was responsible for the change. Distribution of the attributions was severely skewed on both sets of attribution measures, in favor of an internal stable cause (effort), precluding meaningful analyses of the relationship between self-efficacy and attributions. It was also found that attributions changed significantly over time and the experimental experience as measured by the questionnaires. No significant effect of modeling on persistence time was found. The research findings were discussed in terms of the research methodology used, the psychometric properties of the instruments, and implications for the theoretical models.