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- Strongly Robust Toric Ideals in Codimension 2
- A homogeneous ideal is robust if its universal Gr ?obner basis is also a minimal generating set. For toric ideals, one has the stronger definition: A toric ideal is strongly robust if its Graver basis equals the set of indispensable binomials. We characterize the codimension 2 strongly robust toric ideals by their Gale diagrams. This gives a positive answer to a question of Petrovi?, Thoma, and Vladoiu in the case of codimension 2 toric ideals.
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- Mixture models for rating data: the method of moments via Groebner bases
- A recent thread of research in ordinal data analysis involves a class of mixture models that designs the responses as the combination of the two main aspects driving the decision pro- cess: a feeling and an uncertainty components. This novel paradigm has been proven flexible to account also for overdispersion. In this context, Groebner bases are exploited to estimate model parameters by implementing the method of moments. In order to strengthen the validity of the moment procedure so derived, alternatives parameter estimates are tested by means of a simulation experiment. Results show that the moment estimators are satisfactory per se, and that they significantly reduce the bias and perform more efficiently than others when they are set as starting values for the Expectation-Maximization algorithm.
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- Unimodular hierarchical models and their Graver bases
- Given a simplicial complex whose vertices are labeled with positive integers, one can associate a vector configuration whose corresponding toric variety is the Zariski closure of a hierarchical model. We classify all the vertex-weighted simplicial complexes that give rise to unimodular vector configurations. We also provide a combinatorial characterization of their Graver bases.
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- Moment Varieties of Gaussian Mixtures
- The points of a moment variety are the vectors of all moments up to some order, for a given family of probability distributions. We study the moment varieties for mixtures of multivariate Gaussians. Following up on Pearson’s classical work from 1894, we apply current tools from computational algebra to recover the parameters from the moments. Our moment varieties extend objects familiar to algebraic geometers. For instance, the secant varieties of Veronese varieties are the loci obtained by setting all covariance matrices to zero. We compute the ideals of the 5-dimensional moment varieties representing mixtures of two univariate Gaussians, and we offer a comparison to the maximum likelihood approach.
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- Algebraic geometry of Poisson regression
- Designing experiments for generalized linear models is difficult because optimal designs depend on unknown parameters. Here we investigate local optimality. We propose to study for a given design its region of optimality in parameter space. Often these regions are semi-algebraic and feature interesting symmetries. We demonstrate this with the Rasch Poisson counts model. For any given interaction order between the explanatory variables we give a characterization of the regions of optimality of a special saturated design. This extends known results from the case of no interaction. We also give an algebraic and geometric perspective on optimality of experimental designs for the Rasch Poisson counts model using polyhedral and spectrahedral geometry.
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- Professionalism Among Chinese Engineers: An Empirical Study
- Spreadsheet of answers from a questionnaire sent out in 2018-2019 to Chinese engineering students looking at their perceptions of professional and engineering ethics.
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- Stephen Fienberg's influence on algebraic statistics
- Stephen (Steve) E. Fienberg (1942-2016) was an eminent statistician, whose impact on research, education and the practice of statistics, and many other fields is astonishing in its breadth. He was a visionary when it came to linking many different areas to address real scientific issues. He professed the importance of statistics in many disciplines, but recognized that true interdisciplinary work requires joining of the expertise across different areas, and it is in this spirit that he helped steer algebraic statistics toward becoming a thriving subject. Many of his favorite topics in the area are covered in this special issue. We are grateful to all authors for contributing to this volume to honor him and his influence on the field. During the preparation of this issue, we learned about the tragic killing of his widow, Joyce Fienberg, during the Tree of Life Synagogue massacre in Pittsburgh, PA on October 27, 2018. This issue is dedicated to their memory.
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- Fix it: Mending Workshop
- Book chapter from The Sustainable Library's Cookbook
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- Controlling biofilms using synthetic biology approaches
- Bacterial biofilms are formed by the complex but ordered regulation of intra- or inter-cellular communication, environmentally responsive gene expression, and secretion of extracellular polymeric substances. Given the robust nature of bio?lms due to the non-growing nature of bio?lm bacteria and the physical barrier provided by the extracellular matrix, eradicating bio?lms is a very di?cult task to accomplish with conventional antibiotic or disinfectant treatments. Synthetic biology holds substantial promise for controlling bio?lms by improving and expanding existing biological tools, introducing novel functions to the system, and re-conceptualizing gene regulation. This review summarizes synthetic biology approaches used to eradicate bio?lms via protein engineering of bio?lm-related enzymes, utilization of synthetic genetic circuits, and the development of functional living agents. Synthetic biology also enables bene?cial applications of bio?lms through the production of biomaterials and patterning bio?lms with speci?c temporal and spatial structures. Advances in synthetic biology will add novel bio?lm functionalities for future therapeutic, biomanufacturing, and environmental applications., Sponsorship: NIH-R15AI130988, NSF CBET-1917130
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- Incorporation of non-standard amino acids into proteins: challenges, recent achievements, and emerging applications
- The natural genetic code only allows for 20 standard amino acids in protein translation, but genetic code reprogramming enables the incorporation of non-standard amino acids (NSAAs). Proteins containing NSAAs provide enhanced or novel properties and open diverse applications. With increased attention to the recent advancements in synthetic biology, various improved and novel methods have been developed to incorporate single and multiple distinct NSAAs into proteins. However, various challenges remain in regard to NSAA incorporation, such as low yield and misincorporation. In this review, we summarize the recent efforts to improve NSAA incorporation by utilizing orthogonal translational system optimization, cell-free protein synthesis, genomically recoded organisms, artificial codon boxes, quadruplet codons, and orthogonal ribosomes, before closing with a discussion of the emerging applications of NSAA incorporation., Sponsorship: NIH R15AI130988
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- Assessing Graduate Student Progress in Engineering Ethics
- Under a grant from the National Science Foundation, the authors (and others) undertook to integrate ethics into graduate engineering classes at three universities—and to assess success in a way allowing comparison across classes (and institutions). This paper describes the attempt to carry out that assessment. Standard methods of assessment turned out to demand too much class time. Under pressure from instructors, the authors developed an alternative method that is both specific in content to individual classes and allows comparison across classes. Results are statistically significant for ethical sensitivity and knowledge. They show measurable improvement in a single semester.
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- Single Spool Magazine Tape Recorder
- Sponsorship: Armour Research Foundation of Illinois Institute of Technology, United States Patent
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- Magnetic Recording Apparatus
- Sponsorship: Armour Research Foundation of Illinois Institute of Technology, United States Patent
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- Recording Apparatus
- Sponsorship: Armour Research Foundation of Illinois Institute of Technology, United States Patent
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- Metal Cladding Process and Products Resulting Therefrom
- Sponsorship: Armour Research Foundation of Illinois Institute of Technology, United States Patent
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- Spraying Process
- Sponsorship: Armour Research Foundation of Illinois Institute of Technology, United States Patent
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- X-Ray Source
- Sponsorship: Armour Research Foundation of Illinois Institute of Technology, United States Patent
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- Electromagnetic Transducer Head
- Sponsorship: Armour Research Foundation of Illinois Institute of Technology, United States Patent
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- Magnetic Recorder
- Sponsorship: Armour Research Foundation of Illinois Institute of Technology, United States Patent
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- Doing physics : a festschrift for Thomas Erber
- Doing Physics is a festschrift (collection of articles, essays, and rememberances) published in honor of Illinois Tech Physics professor Thomas Erber's 80th birthday. Selections were authored by Erber's colleagues, former stduents, and fellow scholars. This book was released in print form, this file was the original pdf assembled by editor Porter Johnson and submitted for printing with the front and rear covers added.