Polychromatic Colorings on the Integers

We show that for any set $S\subseteq \mathbb{Z}$, $|S|=4$ there exists a 3-coloring of $\mathbb{Z}$ in which every translate of $S$ receives all three colors. This implies that $S$ has a codensity of at most $1/3$, proving a conjecture of Newman [D. J. Newman, Complements of finite sets of integers, Michigan Math. J. 14 (1967) 481--486]. We also consider related questions in $\mathbb{Z}^d$, $d\geq 2$.Comment: 16 pages, improved presentatio

Architecture for Reasoning in Hybrid Discrete-Continuous Domains

Hybrid domains are those featuring a mix of discrete and continuous variables. Recent research has resulted in sophisticated general purpose languages for modeling hybrid domains such as PDDL+ and H as well as efficient planning algorithms based on translation to logical formalisms. However, other reasoning tasks, such as execution monitoring and diagnosis, have not received as much attention. In this thesis, we address this shortcoming and propose execution monitoring and diagnostic reasoning algorithms based on action language H together with an agent architecture that combines planning, diagnostics, and execution monitoring for hybrid domains. The algorithms are based on an expanded translation of action language H to Constraint Answer Set Programming (CASP), which we developed for this project. We demonstrate our approach on two simple, but non-trivial scenarios including one that we tested on an actual robot.M.S.S.E., Software Engineering -- Drexel University, 201

Deep Learning Body Region Classification of MRI and CT examinations

Standardized body region labelling of individual images provides data that can improve human and computer use of medical images. A CNN-based classifier was developed to identify body regions in CT and MRI. 17 CT (18 MRI) body regions covering the entire human body were defined for the classification task. Three retrospective databases were built for the AI model training, validation, and testing, with a balanced distribution of studies per body region. The test databases originated from a different healthcare network. Accuracy, recall and precision of the classifier was evaluated for patient age, patient gender, institution, scanner manufacturer, contrast, slice thickness, MRI sequence, and CT kernel. The data included a retrospective cohort of 2,934 anonymized CT cases (training: 1,804 studies, validation: 602 studies, test: 528 studies) and 3,185 anonymized MRI cases (training: 1,911 studies, validation: 636 studies, test: 638 studies). 27 institutions from primary care hospitals, community hospitals and imaging centers contributed to the test datasets. The data included cases of all genders in equal proportions and subjects aged from a few months old to +90 years old. An image-level prediction accuracy of 91.9% (90.2 - 92.1) for CT, and 94.2% (92.0 - 95.6) for MRI was achieved. The classification results were robust across all body regions and confounding factors. Due to limited data, performance results for subjects under 10 years-old could not be reliably evaluated. We show that deep learning models can classify CT and MRI images by body region including lower and upper extremities with high accuracy.Comment: 21 pages, 2 figures, 4 table

When Programs Collide - A Panel Discussion on the Competing Interests of Analytics and Security

The increasing demand for business analytics and cybersecurity professionals provides an exciting job outlook for graduates of information systems programs. However, the rapid proliferation of devices and systems that has spurred this trend has created a challenging ethical dilemma for those responsible for educating future generations of IT professionals. Many firms are collecting and storing as much data as possible in the hopes that technology might uncover useful insights in the future. This results in an ever-increasing challenge for those charged with protecting organizational assets and exerts pressure on executives seeking an analytical edge to remain profitable in a hyper-competitive marketplace. With this dilemma in mind, the panel will search for a delicate balance between unleashing the power of analytics and securing the sensitive data it consumes. Keyword

Evaluation of a low-cost optical particle counter (Alphasense OPC-N2) for ambient air monitoring

A fast growing area of research is the development of low-cost sensors for measuring air pollutants. The affordability and size of low-cost particle sensors makes them an attractive option for use in experiments requiring a number of instruments such as high density spatial mapping. However, for these low-cost sensors to be useful for these types of studies their accuracy and precision needs to be quantified. We evaluated the Alphasense OPC-N2, a promising low-cost miniature optical particle counter, for monitoring ambient airborne particles at typical urban background sites in the UK. The precision of the OPC-N2 was assessed by co-locating 14 instruments at a site to investigate the variation in measured concentrations. Comparison to two different reference optical particle counters as well as a TEOM-FDMS enabled the accuracy of the OPC-N2 to be evaluated. Comparison of the OPC-N2 to the reference optical instruments demonstrated reasonable agreement for the measured mass concentrations of PM1, PM2.5 and PM10. However, the OPC-N2 demonstrated a significant positive artefact in measured particle mass during times of high ambient RH (> 85 %) and a calibration factor was developed based upon κ-Kohler theory, using average bulk particle aerosol hygroscopicity. Application of this RH correction factor resulted in the OPC-N2 measurements being within 33 % of the TEOM-FDMS, comparable to the agreement between a reference optical particle counter and the TEOM-FDMS (20 %). Reasonable inter-unit precision for the 14 OPC-N2 sensors was observed. Overall, the OPC-N2 was found to accurately measure ambient airborne particle mass concentration provided they are i) correctly calibrated and ii) corrected for ambient RH. The reasonable level of precision demonstrated between multiple OPC-N2 suggests that they would be suitable device for applications where the spatial variability in particle concentration was to be determined

Candida albicans as an essential "keystone" component within polymicrobial oral biofilm models?

Background: Existing standardized biofilm assays focus on simple mono-species or bacterial-only models. Incorporating Candida albicans into complex biofilm models can offer a more appropriate and relevant polymicrobial biofilm for the development of oral health products. Aims: This study aimed to assess the importance of interkingdom interactions in polymicrobial oral biofilm systems with or without C. albicans, and test how these models respond to oral therapeutic challenges in vitro. Materials and Methods: Polymicrobial biofilms (two models containing 5 and 10 bacterial species, respectively) were created in parallel in the presence and absence of C. albicans and challenged using clinically relevant antimicrobials. The metabolic profiles and biomasses of these complex biofilms were estimated using resazurin dye and crystal violet stain, respectively. Quantitative PCR was utilized to assess compositional changes in microbial load. Additional assays, for measurements of pH and lactate, were included to monitor fluctuations in virulence “biomarkers.” Results: An increased level of metabolic activity and biomass in the presence of C. albicans was observed. Bacterial load was increased by more than a factor of 10 in the presence of C. albicans. Assays showed inclusion of C. albicans impacted the biofilm virulence profiles. C. albicans did not affect the biofilms’ responses to the short-term incubations with different treatments. Conclusions: The interkingdom biofilms described herein are structurally robust and exhibit all the hallmarks of a reproducible model. To our knowledge, these data are the first to test the hypothesis that yeasts may act as potential “keystone” components of oral biofilms. © 2020 by the authors. Licensee MDPI, Basel, Switzerland

When Programs Collide: A Panel Report on the Competing Interests of Analytics and Security

The increasing demand for business analytics and cybersecurity professionals provides an exciting job outlook for graduates of information systems programs. However, the rapid proliferation of devices and systems that spurred this trend has created a challenging ethical dilemma for the individuals responsible for educating future generations of information technology professionals. Many firms collect and store as much data as possible in the hope that technology might uncover useful insights in the future. This behavior results in an ever-increasing challenge for those charged with protecting organizational assets and exerts pressure on executives seeking an analytical edge to remain profitable in a hyper-competitive marketplace. With this dilemma in mind, a recent panel discussion at the 14th Annual Midwest Association for Information Systems Conference explored the delicate balance between unleashing the power of analytics and securing the sensitive data it consumes while respecting consumer privacy. This paper reports on that discussion and its insights

A Report on the Status of Standards for Tenure and Promotion in Debate

In what follows, we first provide an overview of debate in order to explain the importance of the activity and then review the status of tenure and evaluation standards among directors/coaches in various types of programs across the country. A mass email was used to ask directors/coaches to submit information about the nature of their current appointment (tenure track, term appointment, and so forth) and the standards through which their performance is evaluated. In addition to seeking information about appointment and evaluation standards for current coaches, we reviewed material from previous developmental conferences and the Quail Roost document, as well as information about how faculty in theater and academic professionals in positions similar to that of a debate director/ coach are evaluated. Following the review of current appointment and evaluation practices, we develop a case for the proposed two tracks for evaluating the performance of debate coaches. We conclude with draft standards