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  1. Free, publicly-accessible full text available February 1, 2023
  2. Growing applications of generative models have led to new threats such as malicious personation and digital copyright infringement. One solution to these threats is model attribution, i.e., the identification of user-end models where the contents under question are generated. Existing studies showed empirical feasibility of attribution through a centralized classifier trained on all existing user-end models. However, this approach is not scalable in a reality where the number of models ever grows. Neither does it provide an attributability guarantee. To this end, this paper studies decentralized attribution, which relies on binary classifiers associated with each user-end model. Each binary classifiermore »is parameterized by a user-specific key and distinguishes its associated model distribution from the authentic data distribution. We develop sufficient conditions of the keys that guarantee an attributability lower bound. Our method is validated on MNIST, CelebA, and FFHQ datasets. We also examine the trade-off between generation quality and robustness of attribution against adversarial post-processes.« less
  3. This paper explores customized scaffolding for pre-service teachers’ problem-solving in technology and engineering discipline. We used clustering analysis to discover natural groupings of scaffolding characteristics which were used in 144 computer-based scaffolding studies from the previous meta-analysis. We first selected input variables based on our research questions which include different scaffolding characteristics, context of use, education level, and effect size. Next, using a two-step clustering algorithm, we found four clusters based on the predominant scaffolding characteristics and profiled each cluster in terms of scaffolding characteristics and their context of use. The resulting cluster solutions indicate what combination of scaffolding characteristicsmore »used in different types of problem-centered learning context would be effective for pre-service teachers’ technology- and engineering-related problem-solving.« less
  4. Research indicates that computer programming in a bricolage manner is equally strong as structure programming. In this study, we investigated how and why 26 preservice, early childhood teachers learning to program employed diverse approaches to programming. Data included classroom videos, interviews, written reflections, submitted code, and questionnaires. Analysis involved open and axial coding. Findings included (a) all tinkered through trial and error but this does not mean that analytical means were never used, (b) divide-and-conquer was practiced, (c) analytical means were often used in locating the bug whereas tinkering was used mostly in fixing the bug, (d) unnoticing when/where tomore »tinker compromised the programming goal, and (e) robot programming was perceived as creative, artistic, and playful.« less
  5. It is often said that computer science is for all students. This implies that it is also for early childhood students, including preschoolers, kindergarteners, and early elementary schoolers. To integrate computer science education into early childhood education, it is necessary to prepare early childhood teachers to do so. In this study, we investigated how and why 15 preservice, early childhood teachers reacted to and addressed challenges when creating block-based programming to control robots. Data sources included classroom recordings, interviews, lesson artifacts, and questionnaires. Analysis strategies included open and axial coding. Findings on hypothesis generation, guess-and-check practice, stereotypical conception, and adaptivemore »attribution to success in programming are discussed.« less
  6. Jiggins, Chris D. (Ed.)
    Our understanding of the evolutionary history of primates is undergoing continual revision due to ongoing genome sequencing efforts. Bolstered by growing fossil evidence, these data have led to increased acceptance of once controversial hypotheses regarding phylogenetic relationships, hybridization and introgression, and the biogeographical history of primate groups. Among these findings is a pattern of recent introgression between species within all major primate groups examined to date, though little is known about introgression deeper in time. To address this and other phylogenetic questions, here, we present new reference genome assemblies for 3 Old World monkey (OWM) species: Colobus angolensis ssp. palliatusmore »(the black and white colobus), Macaca nemestrina (southern pig-tailed macaque), and Mandrillus leucophaeus (the drill). We combine these data with 23 additional primate genomes to estimate both the species tree and individual gene trees using thousands of loci. While our species tree is largely consistent with previous phylogenetic hypotheses, the gene trees reveal high levels of genealogical discordance associated with multiple primate radiations. We use strongly asymmetric patterns of gene tree discordance around specific branches to identify multiple instances of introgression between ancestral primate lineages. In addition, we exploit recent fossil evidence to perform fossil-calibrated molecular dating analyses across the tree. Taken together, our genome-wide data help to resolve multiple contentious sets of relationships among primates, while also providing insight into the biological processes and technical artifacts that led to the disagreements in the first place.« less
  7. Abstract We present the most sensitive and detailed view of the neutral hydrogen ( ${\rm H\small I}$ ) emission associated with the Small Magellanic Cloud (SMC), through the combination of data from the Australian Square Kilometre Array Pathfinder (ASKAP) and Parkes (Murriyang), as part of the Galactic Australian Square Kilometre Array Pathfinder (GASKAP) pilot survey. These GASKAP-HI pilot observations, for the first time, reveal ${\rm H\small I}$ in the SMC on similar physical scales as other important tracers of the interstellar medium, such as molecular gas and dust. The resultant image cube possesses an rms noise level of 1.1 Kmore »( $1.6\,\mathrm{mJy\ beam}^{-1}$ ) $\mathrm{per}\ 0.98\,\mathrm{km\ s}^{-1}$ spectral channel with an angular resolution of $30^{\prime\prime}$ ( ${\sim}10\,\mathrm{pc}$ ). We discuss the calibration scheme and the custom imaging pipeline that utilises a joint deconvolution approach, efficiently distributed across a computing cluster, to accurately recover the emission extending across the entire ${\sim}25\,\mathrm{deg}^2$ field-of-view. We provide an overview of the data products and characterise several aspects including the noise properties as a function of angular resolution and the represented spatial scales by deriving the global transfer function over the full spectral range. A preliminary spatial power spectrum analysis on individual spectral channels reveals that the power law nature of the density distribution extends down to scales of 10 pc. We highlight the scientific potential of these data by comparing the properties of an outflowing high-velocity cloud with previous ASKAP+Parkes ${\rm H\small I}$ test observations.« less
    Free, publicly-accessible full text available January 1, 2023
  8. While there has been much progress in the meaningful integration of computer science within K-12 classrooms, there is a need to promote more equitable participation and to improve teacher preparation. One area in which this is needed is in early childhood education. In this paper, we investigated predictors of debugging quality among 19 pre-service early childhood teachers as they engaged in debugging supported by scaffolding. Bayesian regression indicated the following variables predicted debugging quality: debugging process score, English domain identification, performance approach goals, and sentiment analysis scores applied to what students wrote in response to scaffold prompts.