Manipulating and Controlling for Personality Effects on Visualization Tasks

Researchers in human–computer interaction and visualization have recently been challenged to develop a better understanding of users’ underlying cognitive processes in order to improve system design and evaluation. While existing studies lay a critical foundation for understanding the role of cognitive processes and individual differences in visualization, concretizing the intuition that each user experiences a visual interface through an individual cognitive lens is only half the battle. In this article, we investigate the impact of manipulating users’ personality on observed behavior when using a visualization. In a targeted study, we demonstrate that personality priming can result in changes in behavior when interacting with visualizations. We then discuss how this and similar techniques could be used to control for personality effects when designing and evaluating visualizations systems

Priming Locus of Control to Affect Performance

Recent research suggests that the personality trait Locus of Control (LOC) can be a reliable predictor of performance when learn- ing a new visualization tool. While these results are compelling and have direct implications to visualization design, the relation- ship between a user’s LOC measure and their performance is not well understood. We hypothesize that there is a dependent relation- ship between LOC and performance; specifically, a person’s orientation on the LOC scale directly influences their performance when learning new visualizations. To test this hypothesis, we conduct an experiment with 300 subjects using Amazon’s Mechanical Turk. We adapt techniques from personality psychology to manipulate a user’s LOC so that users are either primed to be more internally or externally oriented on the LOC scale. Replicating previous studies investigating the effect of LOC on performance, we measure users’ speed and accuracy as they use visualizations with varying visual metaphors. Our findings demonstrate that changing a user’s LOC impacts their performance. We find that a change in users’ LOC results in performance changes

Truncating the Y-Axis: Threat or Menace?

Bar charts with y-axes that don't begin at zero can visually exaggerate effect sizes. However, advice for whether or not to truncate the y-axis can be equivocal for other visualization types. In this paper we present examples of visualizations where this y-axis truncation can be beneficial as well as harmful, depending on the communicative and analytic intent. We also present the results of a series of crowd-sourced experiments in which we examine how y-axis truncation impacts subjective effect size across visualization types, and we explore alternative designs that more directly alert viewers to this truncation. We find that the subjective impact of axis truncation is persistent across visualizations designs, even for designs with explicit visual cues that indicate truncation has taken place. We suggest that designers consider the scale of the meaningful effect sizes and variation they intend to communicate, regardless of the visual encoding

Ultrafast relaxation of photoexcited superfluid He nanodroplets

The relaxation of photoexcited nanosystems is a fundamental process of light-matter interaction. Depending on the couplings of the internal degrees of freedom, relaxation can be ultrafast, converting electronic energy in a few fs, or slow, if the energy is trapped in a metastable state that decouples from its environment. Here, we study helium nanodroplets excited resonantly by femtosecond extreme-ultraviolet (XUV) pulses from a seeded free- electron laser. Despite their superfluid nature, we find that helium nanodroplets in the lowest electronically excited states undergo ultrafast relaxation. By comparing experimental pho- toelectron spectra with time-dependent density functional theory simulations, we unravel the full relaxation pathway: Following an ultrafast interband transition, a void nanometer-sized bubble forms around the localized excitation (He ) within 1 ps. Subsequently, the bubble collapses and releases metastable He at the droplet surface. This study highlights the high level of detail achievable in probing the photodynamics of nanosystems using tunable XUV pulses

Soft Chemical Control of Superconductivity in Lithium Iron Selenide Hydroxides Li1–x_{1–x}Fex_x(OH)Fe1–y_{1–y}Se

Hydrothermal synthesis is described of layered lithium iron selenide hydroxides Li$_{1–x}$Fex(OH)Fe$_{1–y}$Se (x$\sim$0.2; 0.02 < $y$ < 0.15) with a wide range of iron site vacancy concentrations in the iron selenide layers. This iron vacancy concentration is revealed as the only significant compositional variable and as the key parameter controlling the crystal structure and the electronic properties. Single crystal X-ray diffraction, neutron powder diffraction, and X-ray absorption spectroscopy measurements are used to demonstrate that superconductivity at temperatures as high as 40 K is observed in the hydrothermally synthesized samples when the iron vacancy concentration is low ($y$ < 0.05) and when the iron oxidation state is reduced slightly below +2, while samples with a higher vacancy concentration and a correspondingly higher iron oxidation state are not superconducting. The importance of combining a low iron oxidation state with a low vacancy concentration in the iron selenide layers is emphasized by the demonstration that reductive postsynthetic lithiation of the samples turns on superconductivity with critical temperatures exceeding 40 K by displacing iron atoms from the Li$_{1–x}$Fe$_x$(OH) reservoir layer to fill vacancies in the selenide layer

Center for By-Products Utilization USE OF COAL COMBUSTION PRODUCTS IN PERMEABLE ROADWAY BASE CONSTRUCTION USE OF COAL COMBUSTION PRODUCTS IN PERMEABLE ROADWAY BASE CONSTRUCTION

SYNOPSIS This paper presents the results of an investigation carried out to develop permeable base course materials using coal combustion products (CCPs) for roadways, highways, and airfield pavements. Three sources of CCPs were selected for this investigation. These include two sources of high-carbon/sulfate-bearing CCPs, which did not meet ASTM C 618 requirements for coal fly ash for use as mineral admixture in concrete, and one source of variable carbon fly ash. These CCPs were used for no-fines/low-fines concrete as a permeable base material. Two types of mixtures were developed using each of these by-products for base course materials. In these mixtures, the amount of fines was varied for the permeable base, one with open-graded and one with an intermediate-graded structure. Tests were performed for fresh concrete properties as well as for compressive strength, splitting tensile strength, flexural strength, etc. The performance of the permeable base mixtures containing CCPs was also compared with a reference mixture without any ash. Test results up to 181 days of testing indicate that CCPs materials can be effectively used as a permeable base course material

Center for By-Products Utilization USE OF COAL COMBUSTION PRODUCTS IN PERMEABLE ROADWAY BASE CONSTRUCTION Use of Coal Combustion Products in Permeable Roadway Base Construction

Abstract This paper presents the results of an investigation carried out to develop permeable base course materials using coal combustion products (CCPs) for roadways, highways, and airfield pavements. Three sources of CCPs were selected for this investigation. These include two sources of high-carbon/sulfate-bearing CCPs, which did not meet ASTM C 618 requirements for coal fly ash for use as mineral admixture in concrete, and one source of variable carbon fly ash. These CCPs were used for no-fines/low-fines concrete as a permeable base material. Two types of mixtures were developed using each of these by-products for base course materials. In these mixtures, the amount of fines was varied for the permeable base, one with open-graded and one with an intermediate-graded structure. Tests were performed for fresh concrete properties as well as for compressive strength, splitting tensile strength, flexural strength, etc. The performance of the permeable base mixtures containing CCPs was also compared with a reference mixture without any ash. Test results up to 181 days of testing indicate that CCPs materials can be effectively used as a permeable base course material