Drawing Graphs with Circular Arcs and Right-Angle Crossings

In a RAC drawing of a graph, vertices are represented by points in the plane, adjacent vertices are connected by line segments, and crossings must form right angles. Graphs that admit such drawings are RAC graphs. RAC graphs are beyond-planar graphs and have been studied extensively. In particular, it is known that a RAC graph with n vertices has at most 4n - 10 edges. We introduce a superclass of RAC graphs, which we call arc-RAC graphs. A graph is arc-RAC if it admits a drawing where edges are represented by circular arcs and crossings form right angles. We provide a Tur\'an-type result showing that an arc-RAC graph with n vertices has at most 14n - 12 edges and that there are n-vertex arc-RAC graphs with 4.5n - o(n) edges

Full throttle:Demonstrating the speed, accuracy, and validity of a new method for continuous two-dimensional self-report and annotation

Research on fine-grained dynamic psychological processes has increasingly come to rely on continuous self-report measures. Recent studies have extended continuous self-report methods to simultaneously collecting ratings on two dimensions of an experience. For all the variety of approaches, several limitations are inherent to most of them. First, current methods are primarily suited for bipolar, as opposed to unipolar, constructs. Second, respondents report on two dimensions using one hand, which may produce method driven error, including spurious relationships between the two dimensions. Third, two-dimensional reports have primarily been validated for consistency between reporters, rather than the predictive validity of idiosyncratic responses. In a series of tasks, the study reported here addressed these limitations by comparing a previously used method to a newly developed two-handed method, and by explicitly testing the validity of continuous two-dimensional responses. Results show that our new method is easier to use, faster, more accurate, with reduced method-driven dependence between the two dimensions, and preferred by participants. The validity of two-dimensional responding was also demonstrated in comparison to one-dimensional reporting, and in relation to post hoc ratings. Together, these findings suggest that our two-handed method for two-dimensional continuous ratings is a powerful and reliable tool for future research

Recognizing Stick Graphs with and without Length Constraints

Stick graphs are intersection graphs of horizontal and vertical line segments that all touch a line of slope -1 and lie above this line. De Luca et al. [GD'18] considered the recognition problem of stick graphs when no order is given (STICK), when the order of either one of the two sets is given (STICK_A), and when the order of both sets is given (STICK_AB). They showed how to solve STICK_AB efficiently. In this paper, we improve the running time of their algorithm, and we solve STICK_A efficiently. Further, we consider variants of these problems where the lengths of the sticks are given as input. We show that these variants of STICK, STICK_A, and STICK_AB are all NP-complete. On the positive side, we give an efficient solution for STICK_AB with fixed stick lengths if there are no isolated vertices

Bounding and Computing Obstacle Numbers of Graphs

An obstacle representation of a graph G consists of a set of pairwise disjoint simply-connected closed regions and a one-to-one mapping of the vertices of G to points such that two vertices are adjacent in G if and only if the line segment connecting the two corresponding points does not intersect any obstacle. The obstacle number of a graph is the smallest number of obstacles in an obstacle representation of the graph in the plane such that all obstacles are simple polygons. It is known that the obstacle number of each n-vertex graph is O(n log n) [Balko, Cibulka, and Valtr, 2018] and that there are n-vertex graphs whose obstacle number is Ω(n/(log log n)²) [Dujmović and Morin, 2015]. We improve this lower bound to Ω(n/log log n) for simple polygons and to Ω(n) for convex polygons. To obtain these stronger bounds, we improve known estimates on the number of n-vertex graphs with bounded obstacle number, solving a conjecture by Dujmović and Morin. We also show that if the drawing of some n-vertex graph is given as part of the input, then for some drawings Ω(n²) obstacles are required to turn them into an obstacle representation of the graph. Our bounds are asymptotically tight in several instances. We complement these combinatorial bounds by two complexity results. First, we show that computing the obstacle number of a graph G is fixed-parameter tractable in the vertex cover number of G. Second, we show that, given a graph G and a simple polygon P, it is NP-hard to decide whether G admits an obstacle representation using P as the only obstacle

Optical/IR from ground

Optical/infrared (O/IR) astronomy in the 1990's is reviewed. The following subject areas are included: research environment; science opportunities; technical development of the 1980's and opportunities for the 1990's; and ground-based O/IR astronomy outside the U.S. Recommendations are presented for: (1) large scale programs (Priority 1: a coordinated program for large O/IR telescopes); (2) medium scale programs (Priority 1: a coordinated program for high angular resolution; Priority 2: a new generation of 4-m class telescopes); (3) small scale programs (Priority 1: near-IR and optical all-sky surveys; Priority 2: a National Astrometric Facility); and (4) infrastructure issues (develop, purchase, and distribute optical CCDs and infrared arrays; a program to support large optics technology; a new generation of large filled aperture telescopes; a program to archive and disseminate astronomical databases; and a program for training new instrumentalists

TEAM EMOTIONAL INTELLIGENCE: LINKING TEAM SOCIAL AND EMOTIONAL ENVIRONMENT TO TEAM EFFECTIVENESS

Work teams are labelled “emotional incubators” because of the ubiquitous emotion generated as team members work together. Although this emotion affects team processes and effectiveness, little theory or research has provided practical information about how teams can manage emotion so that it supports, rather than hinders, team effectiveness. To solve this problem, we draw on social psychological theory suggesting that emotion in teams primarily comes from whether team members’ social and emotional needs (i.e., belonging, shared understanding and control) are satisfied by the team. We then present a study conducted with teams in six U.S. based (four global) companies, testing the relationship between six emotionally intelligent team norms aimed at satisfying team member needs. We hypothesize that incorporating these six norms will lead to high levels of team effectiveness through their influence on the emergence of a productive social and emotional environment (i.e., team psychological safety and team efficacy). Hypotheses are primarily supported. Our study contributes to current knowledge about human social and emotional needs and the influence of emotion and its management on team effectiveness

Integration of Satellite-Derived Cloud Phase, Cloud Top Height, and Liquid Water Path into an Operational Aircraft Icing Nowcasting System

Operational products used by the U.S. Federal Aviation Administration to alert pilots of hazardous icing provide nowcast and short-term forecast estimates of the potential for the presence of supercooled liquid water and supercooled large droplets. The Current Icing Product (CIP) system employs basic satellite-derived information, including a cloud mask and cloud top temperature estimates, together with multiple other data sources to produce a gridded, three-dimensional, hourly depiction of icing probability and severity. Advanced satellite-derived cloud products developed at the NASA Langley Research Center (LaRC) provide a more detailed description of cloud properties (primarily at cloud top) compared to the basic satellite-derived information used currently in CIP. Cloud hydrometeor phase, liquid water path, cloud effective temperature, and cloud top height as estimated by the LaRC algorithms are into the CIP fuzzy logic scheme and a confidence value is determined. Examples of CIP products before and after the integration of the LaRC satellite-derived products will be presented at the conference

TEAM EMOTIONAL INTELLIGENCE: LINKING TEAM SOCIAL AND EMOTIONAL ENVIRONMENT TO TEAM EFFECTIVENESS

Work teams are labelled “emotional incubators” because of the ubiquitous emotion generated as team members work together. Although this emotion affects team processes and effectiveness, little theory or research has provided practical information about how teams can manage emotion so that it supports, rather than hinders, team effectiveness. To solve this problem, we draw on social psychological theory suggesting that emotion in teams primarily comes from whether team members’ social and emotional needs (i.e., belonging, shared understanding and control) are satisfied by the team. We then present a study conducted with teams in six U.S. based (four global) companies, testing the relationship between six emotionally intelligent team norms aimed at satisfying team member needs. We hypothesize that incorporating these six norms will lead to high levels of team effectiveness through their influence on the emergence of a productive social and emotional environment (i.e., team psychological safety and team efficacy). Hypotheses are primarily supported. Our study contributes to current knowledge about human social and emotional needs and the influence of emotion and its management on team effectiveness