Dynamic Search-Space Pruning Techniques in Path Sensitization

Abstract — A powerful combinational path sensitization engine is required for the efficient implementation of tools for test pattern generation, timing analysis, and delay fault testing. Path sensitization can be posed as a search, in the n-dimensional Boolean space, for a consistent assignment of logic values to the circuit nodes which also satisfies a given condition. In this paper we propose and demonstrate the effectiveness of several new techniques for search-space pruning for test pattern generation. In particular, we present linear-time algorithms for dynamically identifying unique sensitization points and for dynamically maintaining reduced head line sets. In addition, we present two powerful mechanisms that drastically reduce the number of backtracks: failure-driven assertions and dependency-directed backtracking. Both mechanisms can be viewed as a form of learning while searching and have analogs in other application domains. These search pruning methods have been implemented in a generic path sensitization engine called LEAP. A test pattern generator, TG-LEAP, that uses this engine was also developed. We present experimental results that compare the effectiveness of our proposed search pruning strategies to those of PODEM, FAN, and SOCRATES. In particular, we show that LEAP is very efficient in identifying undetectable faults and in generating tests for difficult faults. I

Search Algorithms for Satisfiability Problems in Combinational Switching Circuits

A number of tasks in computer-aided analysis of combinational circuits, including test pattern generation, timing analysis, delay fault testing and logic verification, can be viewed as particular formulations of the satisfiability problem (SAT). The first purpose of this dissertation is to describe a configurable search-based algorithm for SAT that can be used for implementing different circuit analysis tools. Several methods for reducing the amount of search are detailed and integrated into a general algorithmic framework for solving SAT. Special emphasis is given to the description of methods for diagnosing the causes of conflicts that may be identified while searching for a solution to each instance of SAT. These methods allow the implementation of non-chronological backtracking, conflict identification based on equivalence relations and logic value assertions derived from conflicts. Path sensitization in combinational circuits is often used to solve test pattern generation, timing analysis and delay fault testing problems. While path sensitization can be cast as an instance of SAT, such an approach can conceal desirable structural properties of the problem and may lead to exponential size representations. Another purpose of this dissertation is to introduce a new model for path sensitization that permits modeling test pattern generation and timing analysis with linear size representations. In addition, this formulation for path sensitization permits the adaptation of all the pruning methods developed for the general SAT problem. The proposed SAT algorithms and path sensitization model form an initial kernel for the development of tools for the analysis of combinational circuits. Their practical applicability is supported by experimental results obtained with test pattern generation and timing analysis tools.Ph.D.Electrical EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/104664/1/9542904.pdfDescription of 9542904.pdf : Restricted to UM users only

Influence of the conditions of sensitization on the characteristics of p-DSCs sensitized with asymmetric squaraines

The effect of the conditions of sensitization on the photoelectrochemical performance of p-type dye-sensitized solar cells (p-DSCs) with screen-printed nickel oxide (NiO) photocathodes is analyzed. The dye-sensitizers employed in the present study are asymmetric squaraines. The conditions of sensitization differ for the relative concentration of the anti-aggregating agentCDCA(chenideoxycholic acid) with respect to the concentration of the dye-sensitizer. The co-adsorption of CDCA onto NiO electrode brings about a decrease in the surface concentration of the anchored dye as well as a blueshift of the characteristic wavelengths of optical absorption of the asymmetric squaraines considered here. Beside this, the employment of CDCA as co-adsorbent reduces the overall conversion performance of the resulting squaraine-sensitized p-DSCs with consequent diminution of the short-circuit current density. This result is ascribed to the acid action of CDCA toward the amminic nitrogen of the squaraines. Quantum efficiency spectra show that CDCA acts as a quencher of the intrinsic photoelectrochemical activity of NiO. Moreover, CDCA does not interfere with the mechanism of charge injection effectuated by the photoexcited squaraines. The photoelectrochemical impedance spectra was analyzed employing a model of equivalent circuit developed for semiconducting nanostructure electrodes

How Do Community-based Legal Programs Work: Understanding the Process and Benefits of a Pilot Program to Advance Women's Property Rights in Uganda

This document presents women's property rights, especially access to land, are increasingly recognized as critical to achieving poverty reduction and gender equality. Research shows that community-based legal aid programs are a viable approach to improving legal knowledge and women's access to legal resources to address property issues. From 2009-2010, the International Center for Research on Women (ICRW) and the Uganda Land Alliance (ULA) implemented and evaluated a pilot program to strengthen women's property rights. This report describes the pilot program's implementation, outcomes and lessons. It details the program design, methodologies for monitoring and evaluation, and the context in which the program was implemented. Findings include a discussion of challenges encountered by the rights workers, overall program achievements, and recommendations for community rights work as an approach to promoting women's property rights

Why does early childhood deprivation increase the risk for depression and anxiety in adulthood? A developmental cascade model

Abstract Background: Using data from the English & Romanian Adoptees (ERA) study we recently reported that early time-lmited exposure to severe institutional deprivation is associated with early onset and persistent neurodevelopmental problems and later onset emotional problems. Here we examine possible reasons for the late emergence of emotional problems in this cohort. Our main focus is on testing a developmental cascade mediated via the functional impact of early-appearing neurodevelopmental problems on late adolescent functioning. We also explore a second putative pathway via sensitization to stress. Methods: The ERA study includes 165 Romanian individuals who spent their early lives in grossly depriving institutions and were subsequently adopted into UK families, along with 52 UK adoptees with no history of deprivation. Age six years symptoms of neurodevelopmental problems and age 15 anxiety/depression symptoms were assessed via parental reports. Young adult symptoms of depression and anxiety were assessed by both parent and self-reports; young adults also completed measures of stress reactivity , exposure to adverse life events and functioning in work and interpersonal relationships. Results: The path between early institutional deprivation and adult emotional problems was mediated via the impact of early neurodevelopmental problems on unemployment and poor friendship functioning during the transition to adulthood. The findings with regard to early deprivation, later life stress reactivity and emotional problems were inconclusive. Conclusions: Our analysis suggests that the risk for adult depression and anxiety following extreme institutional deprivation is explained through the effects of early neurodevelopmental problems on later social and vocational functioning. Future research should more fully examine the role of stress susceptibility in this model