Refining personal and social presence in virtual meetings

Virtual worlds show promise for conducting meetings and conferences without the need for physical travel. Current experience suggests the major limitation to the more widespread adoption and acceptance of virtual conferences is the failure of existing environments to provide a sense of immersion and engagement, or of ‘being there’. These limitations are largely related to the appearance and control of avatars, and to the absence of means to convey non-verbal cues of facial expression and body language. This paper reports on a study involving the use of a mass-market motion sensor (Kinect™) and the mapping of participant action in the real world to avatar behaviour in the virtual world. This is coupled with full-motion video representation of participant’s faces on their avatars to resolve both identity and facial expression issues. The outcomes of a small-group trial meeting based on this technology show a very positive reaction from participants, and the potential for further exploration of these concepts

Random Iteration of Rational Maps

Random and non-autonomous iteration has been a subject of interest in Mathematics that has received some attention in the last few decades. The earliest paper on random iteration in the complex setting was written by Fornaess and Sibony. They have shown that given a family of functions \{f_c\}_{c \in \W} where \W is a small open set, for almost every z the random iteration is stable on a subset of \W^\N of full probability measure. Later, Hiroki Sumi further extended these results to a more general situation using rational semigroups. We will show that the results of Fornaess and Sibony can be extended using the concept of non-generic points. Then we describe the connection between Sumi\u27s kernel Julia set and non-generic points. In the third chapter, we will look at seed iteration. This is where a function $f(w,z)$ is composed in the second variable to get a function $f^n(w,z)$ and then we set $z=w$ to get a sequence of functions $F_n(w)$. We will study the properties of the corresponding Julia and Fatou sets of the sequence $F_n(w)$. Furthermore, we will look at evidence that there may be basins of attraction and sub-invariant domains contained inside the space of analytic functions over a domain $U$, similar to what we see in classical iteration theory

On the ability of rocks to conduct heat in the Lithosphere

This work focuses on creating a model for the conductive thermal transport properties of rocks using measured thermal diffusivity (D) with the Laser Flash Analysis (LFA) method, which eliminates common errors associated with physical contacts and spurious ballistic radiative transfer. Using a suite of 122 samples of 55 Rocks, we develop a new approach to understanding D of rocks by direct, careful, and thorough characterization of the disks used in measurements, and improving our understanding of the minerals that compose samples. Using a newly-developed plagioclase interpolation model, and new measurements for the D of common carbonate minerals, we compare measured to calculated D at ambient and elevated temperature (T). For most samples, D at all Ts is best reproduced using the geometric mixing model, but some samples with clear anisotropy mix according to the series or parallel models. However, many high-temperature measurements are clouded by previously unidentified experimental errors, which typically lower reported D. For application in Earth science, we created a Microsoft Excel spreadsheet which will automatically calculate D(T) of rocks using inputs of temperature, and the relative abundances of phases. Given the random errors found in measurements of rock D, the cost and time required to directly measure thermal transport properties of rocks, and the complex and unpredictable variations in rock characteristics on the scale of samples used to measure D, we recommend using calculated D rather than measured D for modeling thermal conduction in the lithosphere.Includes bibliographical reference

Using Motion Controllers in Virtual Conferencing

At the end of 2010 Microsoft released a new controller for the Xbox 360 called Kinect. Unlike ordinary video game controllers, the Kinect works by detecting the positions and movements of a user’s entire body using the data from a sophisticated camera that is able to detect the distance between itself and each of the points on the image it is capturing. The Kinect device is essentially a low-cost, widely available motion capture system. Because of this, almost immediately many individuals put the device to use in a wide variety applications beyond video games. This thesis investigates one such use; specifically the area of virtual meetings. Virtual meetings are a means of holding a meeting between multiple individuals in multiple locations using the internet, akin to teleconferencing or video conferencing. The defining factor of virtual meetings is that they take place in a virtual world rendered with 3D graphics; with each participant in a meeting controlling a virtual representation of them self called an avatar. Previous research into virtual reality in general has shown that there is the potential for people to feel highly immersed in virtual reality, experiencing a feeling of really ‘being there’. However, previous work looking at virtual meetings has found that existing interfaces for users to interact with virtual meeting software can interfere with this experience of ‘being there’. The same research has also identified other short comings with existing virtual meeting solutions. This thesis investigates how the Kinect device can be used to overcome the limitations of exiting virtual meeting software and interfaces. It includes a detailed description of the design and development of a piece of software that was created to demonstrate the possible uses of the Kinect in this area. It also includes discussion of the results of real world testing using that software, evaluating the usefulness of the Kinect when applied to virtual meetings

Asymptotics of the radiation field for the massless Dirac-Coulomb system

We consider the long-time behavior of the massless Dirac equation coupled to a Coulomb potential. For nice enough initial data, we find a joint asymptotic expansion for solutions near the null and future infinities and characterize explicitly the decay rates seen in the expansion.Comment: 48 pages, 2 figure

Price's law on Minkowski space in the presence of an inverse square potential

We consider the pointwise decay of solutions to wave-type equations in two model singular settings. Our main result is a form of Price's law for solutions of the massless Dirac-Coulomb system in (3+1)-dimensions. Using identical techniques, we prove a similar theorem for the wave equation on Minkowski space with an inverse square potential. One novel feature of these singular models is that solutions exhibit two different leading decay rates at timelike infinity in two regimes, distinguished by whether the spatial momentum along a curve which approaches timelike infinity is zero or non-zero. An important feature of our analysis is that it yields a precise description of solutions at the interface of these two regions which comprise the whole of timelike infinity.Comment: 14 pages, 2 figures; version 2: significant revisions, emphasized Dirac-Coulomb application and clarified expositio

Polaronic conductivity in the photoinduced phase of 1T-TaS2

The transient optical conductivity of photoexcited 1T-TaS2 is determined over a three-order-of-magnitude frequency range. Prompt collapse and recovery of the Mott gap is observed. However, we find important differences between this transient metallic state and that seen across the thermally-driven insulator-metal transition. Suppressed low-frequency conductivity, Fano phonon lineshapes, and a mid-infrared absorption band point to polaronic transport. This is explained by noting that the photo-induced metallic state of 1T-TaS2 is one in which the Mott gap is melted but the lattice retains its low-temperature symmetry, a regime only accessible by photo-doping.Comment: 10 pages, 4 figure

Using Near-Infrared Photography to Better Study Snow Microstructure and Its Variability Over Time and Space

The methods typically used to study snow stratigraphy, microstructure, and variability are expensive, cumbersome, and often highly subjective. Near-infrared (NIR) photography is a low-cost, portable tool to rapidly collect high-resolution, objective measurements of snow microstructure and variability. To expand its application, an active-source NIR flash was introduced to the traditionally passive-source method. NIR imagery was collected alongside proven snowpit methods such as manual observation, Snow Fork wetness, and Snow Micro-Penetrometer hardness profiles. NIR photography was also deployed in five pits along a 10.6 km transect in Grand Mesa, CO, to track stratigraphy variations in space. The NIR flash was found to improve contrast and lower noise for layer detection using automated statistical processing of the images. NIR photography data complemented traditional methods and was shown to provide unique, insightful observations, especially on stratigraphy and microstructure. NIR photography is demonstrated to be a convenient, valuable method to correlate layer stratigraphy across small and large distances. NIR photography is shown to be a rapid snow stratigraphy technique providing repeatable, unique, and informative insight into the complex and rapidly evolving nature of snowpack stratigraphy, microstructure, and variability

Structural Dynamic Stability of Noah\u27s Ark

If the Genesis Flood was a catastrophic event that induced large scale wind driven waves, then the ark that carried Noah and his family needed to be very stable upon large, sometimes random loads. This particular study has several research components that give greater insight into the structural dynamic stability of the ark: (1) a combined numerical-experimental modal analysis on a 1/200th scale ark structure quantifying the first three fundamental resonance frequencies and associated mode shapes: 528 Hz in pitch bending, 800 Hz in yaw bending, and 1000 Hz in torsion; (2) a computational modal analysis that links the 1/200th scale ark structure with the full scale structure of Noah’s Ark showing that the first fundamental frequency ranges from 1–4.5 Hz below the range of human resonances that typically range between 5–10 Hz; and (3) a 1/200th scale ark experimental study on turbulent, random loads with waves that scaled as high as 500 ft (152 m) showing that Noah’s Ark would be stable even under these extreme loads. This combined computational-experimental study clearly shows the stability of the ark under extremely large scale, deleterious conditions