Climate change impacts such as disasters and higher temperatures can disrupt academic learning and reduce academic performance. Here, we use two-ways linear fixed effects regression to estimate the ...effects of short-term school closures (1-5 days) due to wildfires, natural hazard impacts, infrastructure, and student safety on academic performance in California, focusing on mathematics and English scores from state assessments and college preparatory exams. Wildfires are responsible for the majority of school closures. Wildfires generate significant negative impacts on academic performance among younger students. We primarily find insignificant impacts on academic achievement due to school closures from other causes, including from the interaction between number of closure days and socioeconomic and racial/ethnic makeup of the school, across all causes. The effects of school closures lasting more than one week (6-10 days) are also generally insignificant, except for the negative impacts of wildfire closures on elementary school students. These results suggest that older students are resilient to most unexpected short-term school closures (1-5 days) or that teachers can make up lessons effectively after schoolwide closures.
OpenMPL: An Open-Source Layout Decomposer Li, Wei; Ma, Yuzhe; Sun, Qi ...
IEEE transactions on computer-aided design of integrated circuits and systems,
11/2021, Letnik:
40, Številka:
11
Journal Article
Recenzirano
Odprti dostop
Multiple patterning lithography has been widely adopted in advanced technology nodes of VLSI manufacturing. As a key step in the design flow, multiple patterning layout decomposition (MPLD) is ...critical to design closure. Due to the <inline-formula> <tex-math notation="LaTeX">\mathcal {N} \mathcal {P} </tex-math></inline-formula>-hardness of the general decomposition problem, various efficient algorithms have been proposed with high-quality solutions. However, with increasingly complicated design flow and peripheral processing steps, developing a high-quality layout decomposer becomes more and more difficult, slowing down further advancement in this field. This article presents <inline-formula> <tex-math notation="LaTeX">\mathsf {OpenMPL} </tex-math></inline-formula> (2020), an open-source layout decomposition framework, with well-separated peripheral processing and core solving steps. Besides, previous algorithms or techniques are inspected and several issues are discovered. We then propose corresponding new algorithms to resolve these issues. The experiments demonstrate the effectiveness of our proposed algorithms and the efficiency of <inline-formula> <tex-math notation="LaTeX">\mathsf {OpenMPL} </tex-math></inline-formula>.
Because of the widening sub-wavelength lithography gap in advanced fabrication technology, lithography hotspot detection has become an essential task in design for manufacturability. Unlike current ...state-of-the-art works, which unite pattern matching and machine-learning engines, we fully exploit the strengths of machine learning using novel techniques. By combing topological classification and critical feature extraction, our hotspot detection framework achieves very high accuracy. Furthermore, to speed-up the evaluation, we verify only possible layout clips instead of full-layout scanning. We utilize feedback learning and present redundant clip removal to reduce the false alarm. Experimental results show that the proposed framework is very accurate and demonstrates a rapid training convergence. Moreover, our framework outperforms the 2012 CAD contest at International Conference on ComputerAided Design (ICCAD) winner on accuracy and false alarm.
High rates of internal migration throughout the United States offer opportunities to examine the factors underlying residential selection and neighborhood choice. We devise a survey experiment where ...respondents are shown photographs of properties and information about the local socioeconomic environment. By providing and varying additional information about the neighborhood partisan composition, our survey experiment explores how political information affects property evaluation. We find that the same property will be evaluated more favorably by partisans when they learn that it is situated in a predominantly co-partisan neighborhood. A second experiment examines how people make judgments about neighborhood partisan composition in the absence of readily available information. We learn that correct inferences about the politics of a locale can be drawn from non-political information about it, even without exposure to direct information about its partisan balance.
Directed self-assembly (DSA) is one of the leading candidates for extending the resolution of optical lithography to sub-7 nm and beyond. By incorporating DSA in multiple patterning lithography ...(DSA-MP), the flexibility and resolution of contact/via patterning can be further enhanced by using multiple block copolymer (BCP) materials. Prior work faces the dilemma between solution quality and efficiency and is unable to handle 2-D templates. In this article, we capture the essence of template and mask assignment in DSA-MP by a new graph model and a new problem reduction: Our graph model explicitly represents spacing conflict edges and template hyperedges; thus, extra enumeration and manipulation of incompatible via grouping edges can be avoided, and arbitrary 1-D/2-D templates can be natively handled. We further reduce the assignment problem to exact cover, which is encoded by a sparse matrix. Our concise integer linear programming (ILP) formulation and fast backtracking heuristic achieve substantially superior solution quality and efficiency to the state-of-the-art work. Moreover, our problem and graph modelling is flexible and extensible to utilize dummy vias to improve manufacturability. To narrow down the search region of dummy vias, we devise a conflict core finding technique, which is general and applicable to conflict core analysis of exact cover and other multiple patterning layout decomposition problems. Experimental results show the effectiveness and efficiency of our approach.
Questions have been raised in recent years about the extent to which the nation is segregated by the political preferences of its electorate. Some have argued that internal migration selects either ...directly or indirectly on political criteria and thereby produces increasingly one-sided Republican and Democratic neighborhoods. We are among the first to empirically examine voter migration on a large scale. Relying on data for millions of partisan migrants across seven states, we show that partisans relocate based on destination characteristics such as racial composition, income, and population density but additionally prefer to relocate in areas populated with copartisans. This tendency is stronger among Republicans but is also true of Democratic registrants. Whether the role of partisanship is central or ancillary, if it is any part of the decision process it has the potential to make important imprints on the political landscape of the United States.
Layout pattern classification, which groups similar layout clips into clusters, underlies a variety of design for manufacturability (DFM) applications, such as hotspot library generation, ...hierarchical data storage, and yield optimization speedup. The key challenges of layout pattern classification are clip representation and clip clustering. In this paper, we present a fast and general layout pattern classification algorithm considering clip shifting and centroid recreation. Our simple but general clip representation captures both topology and density; we can handle not only rigid area match or edge displacement constraints but also variant edge tolerances and don't care regions. For achieving a small cluster count, our clip clustering is guided by the natural grouping structure of layout clips. The clustering results are further improved by centroid recreation. Our experiments are conducted on 2016 CAD contest at ICCAD benchmark suite. Our results show that our algorithm outperforms the reference solution and all contest winning teams, delivering the smallest cluster count, fastest runtime, and 100% validity. Moreover, our algorithm with clip shifting and centroid recreation further reduces the cluster count effectively and efficiently. In addition to the good solution quality, the interplay between adopted data structures and our algorithm makes it fast and viable to be incorporated into practical DFM flows.
Multiple patterning lithography has been recognized as one of the most promising solutions, in addition to extreme ultraviolet lithography, directed self-assembly, nanoimprint lithography, and ...electron beam lithography, for advancing the resolution limit of conventional optical lithography. Multiple patterning layout decomposition (MPLD) becomes more challenging as advanced technology introduces complex coloring rules. Existing works model MPLD as a graph coloring problem; nevertheless, when complex coloring rules are considered, layout decomposition can no longer be modeled accurately by graph coloring. Therefore, in this paper, for capturing the essence of layout decomposition with complex coloring rules, we model the MPLD problem as an exact cover problem. We then propose a fast and exact MPLD framework based on augmented dancing links. Our method is flexible and general: it can consider the basic and complex coloring rules simultaneously, can maintain density balancing, and can handle quadruple patterning and beyond. Experimental results show that our approach outperforms state-of-the-art works on reported conflicts and stitches and is promising for handling complex coloring rules and density balancing as well.
Abstract
We examine spatial patterns of three types of Environmental Protection Agency violation, hazardous waste, water, and air quality, at the facility level. Since facilities operate ...independently, our null hypothesis is that their violations should be spatially randomly distributed. That is, we do not expect to observe spatial clusters of violations. In addition, systemic factors such as socio-demographic characteristics as well as environmental justice indices should not correlate with violations. Empirically, we find both hypotheses are refuted. Our findings confirm that environmental inequalities have been exacerbated by underlying social vulnerabilities, particularly in the case of Native Indian territories, which consistently show a disproportionately high number of environmental violations. We identify ‘hot spots’, spatial clusters where the number of violations is higher than expected in such a way that cannot be explained by socio-demographic or environmental factors. These hot spots call for local case studies to further investigate causes of spatial clustering of violations.
Timing analysis and optimization is essential for each stage throughout the entire design flow to achieve timing closure. This talk provides a retrospective and prospective study to highlight two ...categories of emerging timing challenges: 1) analysis efficiency and scalability, and 2) advanced process effect on timing. We survey recent advances for handling these challenges and provide future research directions in timing.
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