Delay testing is used to detect timing defects and ensure that a circuit meets its timing specifications. The growing need for delay testing is a result of the advances in deep submicron (DSM) semiconductor technology and the increase in clock frequency. Small delay defects that previously were benign now produce delay faults, due to reduced timing margins. This research focuses on the development of new test methods for small delay defects, within the limits of affordable test generation cost and pattern count. First, a new dynamic compaction algorithm has been proposed to generate compacted test sets for K longest paths per gate (KLPG) in combinational circuits or scan-based sequential circuits. This algorithm uses a greedy approach to compact paths with non-conflicting necessary assignments together during test generation. Second, to make this dynamic compaction approach practical for industrial use, a recursive learning algorithm has been implemented to identify more necessary assignments for each path, so that the path-to-test-pattern matching using necessary assignments is more accurate. Third, a realistic low cost fault coverage metric targeting both global and local delay faults has been developed. The metric suggests the test strategy of generating a different number of longest paths for each line in the circuit while maintaining high fault coverage. The number of paths and type of test depends on the timing slack of the paths under this metric. Experimental results for ISCAS89 benchmark circuits and three industry circuits show that the pattern count of KLPG can be significantly reduced using the proposed methods. The pattern count is comparable to that of transition fault test, while achieving higher test quality. Finally, the proposed ATPG methodology has been applied to an industrial quad-core microprocessor. FMAX testing has been done on many devices and silicon data has shown the benefit of KLPG test.

Dissertation (Ph.D.)--Auburn University,2007. / Abstract. Includes bibliographic references (p.99-103).

Thesis (M.S.)--University of Missouri-Columbia, 2003. / Typescript. Vita. Includes bibliographical references (leaves 26-28). Also available on the Internet.

Thesis (M.S.)--University of Missouri-Columbia, 2003. / Typescript. Vita. Includes bibliographical references (leaves 26-28). Also available on the Internet.

Thesis (M. Sc.)--University of Hong Kong, 1967. / Mimeographed.

The cerebellum is a region of the brain responsible for an organism’s ability to perform precise, coordinated movements. An abundance of research has characterized the anatomy of the cerebellum, and provides the foundation of current theories regarding the circuitry that supports motor learning. Delay eyelid conditioning is a form of motor learning. It is the learned association of a neutral stimulus and the reflexive response of an eyelid closure resulting in a well-timed eyelid closure in anticipation of the reflexive response. Two aspects of this learning are: different-conditioned stimulus savings and savings of timing. Different-CS savings is a rapid re-learning to a new, different neutral stimulus that occurs more quickly than learning to the original stimulus. Savings of timing is a phenomenon in which the timing of a response is preserved from a prior training experience. This dissertation presents evidence that forebrain input to the cerebellum is required for these aspects of delay eyelid conditioning. We trained animals with electrical stimulation as our neutral stimulus and thereby engaged a specific input pathway to the cerebellum, limiting forebrain inputs. In Chapter 2 we implement this technique and eliminate different-CS savings. These data suggest that forebrain input mediates this phenomenon. We then proceeded to investigate if the prefrontal cortex (PFC) is the forebrain region involved in supporting this aspect of delay eyelid conditioning. We administered electrolytic lesions to the PFC of animals and found their ability to express different-CS savings was impaired. Evidence from these two chapters suggests the PFC provides input to the cerebellum necessary for different-CS savings. Finally, in Chapter 4 we examine savings of timing. We again limit forebrain input to the cerebellum and implement electrical stimulation as our neutral training stimulus. With stimulation as the neutral stimulus, animals do not exhibit savings of timing. The data suggest that a forebrain region is necessary to sustain this phenomenon as well. This dissertation provides two lines of evidence strongly supporting forebrain involvement in these modifications of delay eyelid conditioning - savings and savings of timing. These results convey the importance of accommodating forebrain-cerebellum interactions when developing theories of cerebellar function. / text

As exposure to college becomes increasingly integral to individual growth and societal economic vitality, the delay of postsecondary enrollment may be undertaken at a cost to both the individual and society. In addition, this delay represents a rupture in an ideally seamless P-16 educational continuum. Using a combined model of college choice adjusted to account for immediate versus delayed enrollment as well as persistence and graduation, this study addressed whether a student’s postsecondary enrollment delay may contribute to his or her persistence or inability to persist once enrolled in college. To this end, a unique dataset was constructed to reflect student profiles from high school through college and was used to analyze the college-going behaviors of the 2004 cohort of Texas public high school graduates, as well as their participation in the workforce. Descriptive statistics were assembled to characterize immediate enrollers in contrast to delayed enrollers, especially in regard to demographic characteristics and academic preparation. The role of delay in college persistence was measured through the undertaking of eight logistic regression models that accounted for the role of demographic characteristics, academic preparation, and higher education institutional choice, along with the delay factor, on persistence. Findings revealed that students considered at-risk and who are from minority groups are likely to delay enrollment. As well, students who are less academically prepared are overrepresented among delayers. The results of the logistic regression models reveal, moreover, that whatever disadvantage these particular groups experienced in regard to enrolling in postsecondary education, it may have been exacerbated by their delayed enrollment: delayers, in all models, were less likely to persist in college once they enrolled. For the policymaker, educator, or P-16 administrator, this study underscores the need to ensure that students’ academic careers receive early and frequent intervention, in case they decide they wish to enroll in college after graduation. Groups that lack certain types of social capital that facilitate access to postsecondary education ought to be provided appropriate counseling. Above all, the study highlights that access to college is simply not enough if college completion is as important as college enrollment. / text

published_or_final_version / Electrical and Electronic Engineering / Master / Master of Philosophy

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