Interstellar: Using Halide's Scheduling Language to Analyze DNN Accelerators

We show that DNN accelerator micro-architectures and their program mappings represent specific choices of loop order and hardware parallelism for computing the seven nested loops of DNNs, which enables us to create a formal taxonomy of all existing dense DNN accelerators. Surprisingly, the loop transformations needed to create these hardware variants can be precisely and concisely represented by Halide's scheduling language. By modifying the Halide compiler to generate hardware, we create a system that can fairly compare these prior accelerators. As long as proper loop blocking schemes are used, and the hardware can support mapping replicated loops, many different hardware dataflows yield similar energy efficiency with good performance. This is because the loop blocking can ensure that most data references stay on-chip with good locality and the processing units have high resource utilization. How resources are allocated, especially in the memory system, has a large impact on energy and performance. By optimizing hardware resource allocation while keeping throughput constant, we achieve up to 4.2X energy improvement for Convolutional Neural Networks (CNNs), 1.6X and 1.8X improvement for Long Short-Term Memories (LSTMs) and multi-layer perceptrons (MLPs), respectively.Comment: Published as a conference paper at ASPLOS 202

Case report: identification of one frameshift variant and two in cis non-canonical splice variants of NEB gene in prenatal arthrogryposis

NEB mutation is associated with congenital nemaline myopathies. Here, we report a family with recurrent prenatal arthrogryposis. Trio whole exome sequencing (WES) disclosed three novel NEB (NM_001271208.2) variants including one paternal frameshift c.19049_19050delCA (p.Thr6350Argfs*14) and two double maternal variants in cis c. [24871G>T;24871-10C>G] (p. [Val8291Phe;?]). They are evaluated as “likely pathogenic (LP)”, “variant of uncertain of significance (VUS)”, and “VUS”, respectively. After further prediction, the c.24871G>T, c.24871-10C>G, and c.[24871G>T;24871-10C>G] were respectively genetically engineered into the three plasmids. Compared with their wild-type counterparts, the three plasmids all produced truncated transcripts, and also a significant proportion of the full-length transcripts, which allowed us to reclassify NEB c.24871G>T and c.24871-10C>G variants as LP. As far as we know, this is the first case carrying NEB allele-specific function of partial loss. This result helped the couple make informed reproductive choices and opt for assisted reproduction for future pregnancies. This study also increased awareness to the phenotype of prenatal nemaline myopathy and expanded the variant spectrum of NEB

Electrochemical study on effect of colloidal Au on horseradish peroxidase in polypyrrole layer at prussian blue modified electrode

1917-1922Cyclic voltammetry and current-time curve have been used to investigate the Au-colloid function on the horseradish peroxidase biosensor response. Firstly Prussian blue is deposited on the electrode, and then the polypyrrole (PPY)/HRP biosensor is constructed by electrochemical oxidization of pyrrole in the solution containing horseradish peroxidase and pyrrole. The colloidal Au is then immobilized on the electrode. Cyclic voltammograms show higher current in the presence of Au-colloid as compared to that in the absence of the colloid. The PB/PPY/HRP and PB/PPY/HRP/Au-colloid biosensors exhibit linear current-time response to hydrogen peroxide over a concentration range of 2χ10⁻⁶ M – 1.8χ10⁻⁴ M. Michaelis-Menten constants of the two biosensors are 0.63 and 0.35 mM, respectively. The dependence of current responses on applied voltage has been discussed and the mechanism has been proposed. The results show that colloidal Au enhances the current response and decreases the energy barrier of electron transfer reaction on the electrode. The interference of foreign substances has also discussed

Student Health Implications of School Closures during the COVID-19 Pandemic: New Evidence on the Association of e-Learning, Outdoor Exercise, and Myopia

The coronavirus disease 2019 (COVID-19) pandemic forced many education systems to consider alternative remote e-learning modalities, which have consequential behavioral and health implications for youth. In particular, increased e-learning engagement with digital screens and reduction in outdoor activities are two likely channels posing adverse risks for myopia development. This study investigated the association between e-learning screen use, outdoor activity, lighting condition, and myopia development among school-age children in China, during the first wave of the COVID-19 pandemic. Data were collected from 3405 school-age children attending primary, lower-secondary, and upper-secondary schools in China. Univariate parametric and nonparametric tests, and multivariate logistic regression analysis were used. Findings show that each diopter hour increase in daily e-learning screen use is significantly associated with progression of myopia symptoms (OR: 1.074, 95% CI: 1.058–1.089; p < 0.001), whereas engaging in outdoor exercise four to six times per week (OR: 0.745, 95% CI: 0.568–0.977; p = 0.034) and one to three times per week (OR: 0.829, 95% CI: 0.686–0.991; p = 0.048) is associated with a lower likelihood of myopia progression than none at all. In addition, we found that indoor lighting that is either “too dim” (OR: 1.686, 95% CI: 1.226–2.319; p = 0.001) or “too bright” (OR: 1.529, 95% CI: 1.007–2.366; p = 0.036) is significantly associated higher likelihood of myopic symptoms. Findings in this study uncover the less observable vision consequences of the COVID-19 pandemic on youths through digital online learning and highlight the importance of considering appropriate mitigation strategies to deal with this emerging public health challenge

Retrieval of Land Surface Component Temperature by Particle Swarm Optimization Algorithm

The temperature of the individual components can differ significantly, introducing errors in the quantity estimations by remote sensing technique. Because the measured radiation by these sensors can be an aggregation of radiation emitted by the different canopy components, the objective of this research was to create an inversion scheme to retrieve three component temperatures: vegetation, sunlit soil and shade soil temperature by Particle swarm optimization algorithm in the YingKe wheat study area. Given Aster spatial resolution varies with wavelength: 15 m in the visible and 90 m in the thermal infrared (TIR), area ratios of components in the pixel is acquired by the optical part of the spectrum to improve component temperature retrieval precision. Comparing with field measured data, the results showed that comparing simultaneous field data, the error range of simulated temperature under condition of considering thermal radiation and reflectance data was 1.5271 %-9.58 %. There for, the retrieval method for land Surface Component Temperature by Particle Swarm Optimization Algorithm is feasible

Assessment of student knowledge integration in learning work and mechanical energy

Work and mechanical energy is a fundamental topic in introductory physics. Studies in existing literature have shown that students have difficulties in understanding work and mechanical energy, particularly the topic of work-energy theorem. To study students’ knowledge integration in learning work and mechanical energy, a conceptual framework model of work and mechanical energy was developed and applied to guide the design of an assessment for measuring students’ level of knowledge integration. Using the assessment, qualitative and quantitative data were collected in two high schools in an eastern Chinese city. The results reveal that the conceptual framework model can effectively represent the students’ knowledge structures at different levels of knowledge integration. In addition, the assessment is shown effective in identifying unique features of knowledge integration, including context dependence and fragmentation of knowledge components, memorization-based problem-solving strategies, and lack of meaningful connections between work and change in kinetic energy. The conceptual framework of work and mechanical energy and assessment results can provide useful information to facilitate instructional designs to promote knowledge integration

Development of a multiple-choice problem-solving categorization test for assessment of student knowledge structure

Problem-solving categorization tasks have been well studied and used as an effective tool for assessment of student knowledge structure. In this study, a traditional free-response categorization test has been modified into a multiple-choice format, and the effectiveness of this new assessment is evaluated. Through randomized testing with Chinese college students, the multiple-choice categorization test has been shown to provide equivalent measurement compared to the open-ended test. In addition, the influence of including diagrams in problems on students’ categorization performances has also been studied, which suggests that the inclusion of diagrams in problems can improve students’ performances in identifying the relevant concepts. The results also show that the knowledge structures of the Chinese college students are in the early transitional stage between novices and experts

Assessment of student understanding on light interference

Light interference is an essential topic for understanding the wavelike nature of light, however, there are limited studies on modeling and assessing students’ misconceptions and learning difficulties in this area. Based on the knowledge integration modeling approach, a conceptual framework for light interference is developed and used to model student understanding and guide the development of an assessment tool on light interference. The conceptual framework provides a representation of students’ reasoning pathways to clearly show their connections through different conceptual components and contextual features of problem-solving settings. This type of representation focuses on showing students’ knowledge structures regarding the features of integration and fragmentation. Experts’ reasoning pathways always flow through a central idea of a concept with well-established connections to a wide range of contextual features and conditions. These connections form an integrated knowledge structure, which demonstrates deep understanding. In contrast, novices often focus on surface details without linking the central idea, forming fragmented local connections that link directly between contextual features and task outcomes. As a result, novice students’ problem solving often relies on memorization of formula and solutions without any deep understanding. Through testing and interviews at a large Chinese university, a light interference test (LIT) has been developed and validated. Assessment results also demonstrate that students with a strong conceptual understanding of the central idea are able to apply expertlike reasoning to familiar and novel questions regardless of the contextual details. Meanwhile, students with weaker or nonexistent understanding of the central idea often struggle when novel situations are presented. LIT provides a useful tool to measure students’ conceptual understanding on light interference and probe thought pathways of students’ reasoning that can further indicate students’ knowledge structure and levels of deep understanding

Assessment of knowledge integration in student learning of momentum

Momentum is a foundational concept in physics. Although it is often taught in introductory mechanics courses, there are a limited number of studies on this topic in the literature. The results from these studies have consistently shown that students have difficulties in understanding momentum, especially the connections between net force, time, and change in momentum, which are signs of fragmented knowledge structure and poor knowledge integration. This study adopts the conceptual framework representation to model student understanding and guide the design of an assessment test on momentum. Informed by the previous work on knowledge integration, the conceptual framework maps out the key concepts and their connections within a student’s knowledge structure. Recent studies have shown that a conceptual framework can be used as a guide to create assessment items that follow different reasoning pathways, probing various misconceptions and student difficulties. In this study, an assessment of momentum was developed and tested among a large number of U.S. college freshmen and Chinese high school students. Based on testing and interview results, students’ understanding is separated into three progression levels of knowledge integration including novicelike, transitional, and expertlike. Furthermore, the comparison between the two countries’ curriculum and momentum test results indicates that an emphasis on the central idea of impulse-momentum theorem can be an essential instructional strategy to help students make the necessary connections within their knowledge structure, leading to a deeper conceptual understanding of momentum

Limited role of sessile acidophiles in pyrite oxidation below redox potential of 650 mV

Pyrite oxidation by mixed mesophilic acidophiles was conducted under conditions of controlled and non-controlled redox potential to investigate the role of sessile microbes in pyrite oxidation. Microbes attached on pyrite surfaces by extracellular polymeric substances (EPS), and their high coverage rate was characterized by scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM) and atomic force microscopy (AFM). The dissolution of pyrite was negligible if the redox potential was controlled below 650 mV (near the rest potential of pyrite), even though the bacteria were highly active and a high coverage rate was observed on pyrite surfaces. However, with un-controlled redox potential the rate of pyrite oxidation increased greatly with an increasing redox potential. This study demonstrates that sessile microbes play a limited role in pyrite oxidation at a redox potential below 650 mV, and highlight the importance of solution redox potential for pyrite oxidation. This has implications for acid mine drainage control and pyrite oxidation control in biometallurgy practice.</p