CDCL SAT solver heuristics: Clause management, instance structure, and decisions

The Boolean satisfiability problem or SAT is the problem of deciding if a Boolean formula has a satisfying assignment. It was the first problem shown to be NP-complete, and remains one of the most well-known and studied NP-complete problems. We do not expect to find a polynomial time algorithm that solves all SAT problems, as this would imply equivalence of the complexity classes P and NP, which seems unlikely. However, there are algorithms and heuristics to solve SAT problems that are often effective in practice. A SAT solver is a program that takes as input a Boolean formula and tries to find a satisfying assignment for it. The most-used algorithm in SAT solvers intended for solving real-world problems is known as Conflict Driven Clause Learning, abbreviated CDCL. Due to its broad usage, improving the performance of these solvers can have a large impact on other fields that use SAT solvers and also make SAT solving a useful tool for more applications. The practical performance of CDCL SAT solvers depends critically on a small number of key heuristic mechanisms, and works on these heuristics over the past 20 years have improved CDCL solver performance significantly. This dissertation contributes to our understanding of two of the key heuristic mechanisms, known as the decision heuristic and the clause database management scheme. There are two main foci, which are closely related. First, we focus on developing light weighted methods to use measures of instance structure in solver heuristics. The structure of instances arising from real-world problems seems to be one of the main features that makes them special but there is little work exploiting structural properties within CDCL solvers. We introduce a new structural measure for SAT instances, called Centrality, and show that this measure can be used in both decision and clause management heuristics to improve solver performance. Second, we study different components of clause database management schemes in order to understand and improve them. We categorize clauses as permanent and temporary, show that the permanent set is key to solver performance and propose modifications to the criteria for permanent clauses to improve performance. In recent years, clause database management strategies used in high-performance solvers have become complex, making their study and refinement difficult. We introduce a new clause reduction scheme, called online deletion, which is simple to implement and results in comparable performance

Poetics of the [Selves]∞: An Active Aesthetic

This practitioner-based research reports on the development and assessment of a transdisciplinary pedagogical model for the learning sciences. The theoretical underpinnings of Poetics of the [Selves]∞ draw from three domains of knowledge: (1) mindfulness, (2) positive psychology, and (3) contemporary performance. The approach is designed to create positive self-transformation in participants as a result of engaging them in a sequence of activities that require different modes of reflection. The model was tested in two settings: a collaborative learning space, and a university classroom. The sample from the first workshop included individuals from the general public, and middle and high-school foreign language teachers comprised the second workshop. The data sources that underwent analysis included audio-visual documentation from each workshop. This qualitative study employed the principles and methods of Interactional Ethnography and critical discourse analysis to construct two telling cases of Poetics of the [Selves]∞. Analytic results from both workshops suggest that Poetics of the [Selves]∞ has the potential to enhance self-awareness and increase positive affect toward others. Moreover, the results of the second workshop showed its potential value in foreign language classrooms as it promoted authentic content connections, built rapport, and reinforced knowledge by activating different modes of learning in participants

Navigating the cultural gaps: Whiteness and diversity in two elementary school classrooms

This study asked how two white, in-service elementary school teachers within the context of their classrooms navigated the cultural gaps between themselves and students from whom they differed (e.g. racially, ethnically, socio-economically, and/or linguistically). Three sub-questions examined: 1) what life experiences shaped how the teachers understood difference and diversity within their classrooms; 2) what system(s) of beliefs the teachers learned and constructed through those experiences; and 3) what identities the teachers assumed and/or assigned to themselves and their students. The study employed a sociocultural theoretical framework. Ethnographic data collection strategies included participant observation, semi-structured interviews, and material collection. Discourse analysis acted as the analytic framework. The findings indicate that the participants drew upon their life experiences and the values and beliefs they acquired and constructed through those experiences to make meaning of diversity in their classrooms and to shape the actions and interactions within their classrooms. Their life experiences seem to have influenced how the participants grappled with the Deficit Thinking and White Knight Discourse models in their explicit and implicit forms. Understanding the social context in which they taught, the participants structured their classrooms and their interactions to address their students\u27 academic needs on the one hand and their social and emotional needs on the other. Additionally, the participants fostered identities of achievement in their students. To bridge the cultural gaps, the participants explored and developed a sense of their students\u27 experiential diversity, and they formed relationships with others who could support them in their work. The final finding focused on how interacting throughout the course of this study providing the participants with the opportunity to examine their own autobiographies and the impact of those autobiographies on their teaching. The implications of this study include: 1) the relevance of teachers\u27 life experiences to their teaching practice, 2) the importance of understanding the social context in which one teaches, 3) different strategies teachers might employ in working with culturally diverse students, and 4) future research based on the process of this investigation as a means of encouraging teachers to critically examine their own autobiographies

Creating the Future of Health

Creating the Future of Health is the fascinating story of the first fifty years of the Cumming School of Medicine at the University of Calgary. Founded on the recommendation of the Royal Commission on Health Services in 1964 the Cumming School has, from the very beginning, focused on innovation and excellence in health education. With a pioneering focus on novel, responsive and systems-based approaches, it was one of the first faculties to pilot multi-year training programs in family medicine and remains one of only two three-year medical schools in North America. Drawing on interviews with key players and extensive research into documents and primary material, Creating the Future of Health traces the history of the school through the leadership of its Deans. This is a story of perseverance through fiscal turbulence, sweeping changes to health care and health care education, and changing ideas of what health services are and what they should do. It is a story of triumph, of innovation, and of the tenacious spirit that thrives to this day at the Cumming School of Medicine

Estimating the Size and Structure of the Underground Commercial Sex Economy in Eight Major U.S. Cities

The underground commercial sex economy (UCSE) generates millions of dollars annually, yet investigation and data collection remain under resourced. Our study aimed to unveil the scale of the UCSE in eight major US cities. Across cities, the UCSE's worth was estimated between $39.9 and$290 million in 2007, but decreased since 2003 in all but two cities. Interviews with pimps, traffickers, sex workers, child pornographers, and law enforcement revealed the dynamics central to the underground commercial sex trade -- and shaped the policy suggestions to combat it

Politics, Professionalism and Power

This book examines the role of increased professionalism in the growth of both the Republican and Democratic national parties, beginning with Republican National Committee Chairman Ray C. Bliss in the 1960s. It analyzes how an increased application of professional values has contributed to the continued growth of national party organizations, despite recurring constraints in party policymaking.https://ideaexchange.uakron.edu/politics_professionalism_power/1000/thumbnail.jp

Transforming our World through Universal Design for Human Development

An environment, or any building product or service in it, should ideally be designed to meet the needs of all those who wish to use it. Universal Design is the design and composition of environments, products, and services so that they can be accessed, understood and used to the greatest extent possible by all people, regardless of their age, size, ability or disability. It creates products, services and environments that meet people’s needs. In short, Universal Design is good design. This book presents the proceedings of UD2022, the 6th International Conference on Universal Design, held from 7 - 9 September 2022 in Brescia, Italy.The conference is targeted at professionals and academics interested in the theme of universal design as related to the built environment and the wellbeing of users, but also covers mobility and urban environments, knowledge, and information transfer, bringing together research knowledge and best practice from all over the world. The book contains 72 papers from 13 countries, grouped into 8 sections and covering topics including the design of inclusive natural environments and urban spaces, communities, neighborhoods and cities; housing; healthcare; mobility and transport systems; and universally- designed learning environments, work places, cultural and recreational spaces. One section is devoted to universal design and cultural heritage, which had a particular focus at this edition of the conference. The book reflects the professional and disciplinary diversity represented in the UD movement, and will be of interest to all those whose work involves inclusive design

Teaching an Old Robot New Tricks: Learning Novel Tasks via Interaction with People and Things

As AI has begun to reach out beyond its symbolic, objectivist roots into the embodied, experientialist realm, many projects are exploring different aspects of creating machines which interact with and respond to the world as humans do. Techniques for visual processing, object recognition, emotional response, gesture production and recognition, etc., are necessary components of a complete humanoid robot. However, most projects invariably concentrate on developing a few of these individual components, neglecting the issue of how all of these pieces would eventually fit together. The focus of the work in this dissertation is on creating a framework into which such specific competencies can be embedded, in a way that they can interact with each other and build layers of new functionality. To be of any practical value, such a framework must satisfy the real-world constraints of functioning in real-time with noisy sensors and actuators. The humanoid robot Cog provides an unapologetically adequate platform from which to take on such a challenge. This work makes three contributions to embodied AI. First, it offers a general-purpose architecture for developing behavior-based systems distributed over networks of PC's. Second, it provides a motor-control system that simulates several biological features which impact the development of motor behavior. Third, it develops a framework for a system which enables a robot to learn new behaviors via interacting with itself and the outside world. A few basic functional modules are built into this framework, enough to demonstrate the robot learning some very simple behaviors taught by a human trainer. A primary motivation for this project is the notion that it is practically impossible to build an "intelligent" machine unless it is designed partly to build itself. This work is a proof-of-concept of such an approach to integrating multiple perceptual and motor systems into a complete learning agent