186 research outputs found
Comb-mode-resolving broadband Fourier transform spectroscopy
No full textThis report demonstrates progress made to develop a robust turn-key astrocomb architecture for the calibration package of the HIRES spectrograph planned for installation on the upcoming Extremely-Large Telescope (ELT) which intends to enable novel research across a range of scientific disciplines. Here, we demonstrate progress towards a laser frequency comb covering optical and infra-red wavelength ranges and made possible by use of nonlinear interactions driven by a single stabilised mode-locked laser source. We also detail a proof-of-concept experiment carried out with a compact broadband Fourier-transform spectrometer to identify the subset of filtered frequency-comb modes, an important ancillary technology for any future broadband Fabry-P´erot-based astrocomb
Mid-infrared photonic imaging strategies
No full textImaging at mid-infrared (MIR) wavelengths between from 3–12 µm can provide unique
insights and contrast mechanisms because of the low scattering of MIR light and the chemical
specificity of MIR absorption. Consequently, new light sources and spectroscopic methods
applied in the MIR offer previously unavailable capabilities for MIR hyperspectral (HS) or
depth-resolved imaging. In this thesis, I report the development of three new MIR imaging
techniques, configured in particular for applications in heritage science.
Current MIR HS imaging technologies are expensive, as they employ complex cooled
MIR detectors, or slow, in terms of acquisition rates. These factors limit widespread use
in certain applications such as pigment mapping of paintings for cultural heritage. Here, I
demonstrate two relatively inexpensive and fast HS imaging systems which utilise novel
compressive sensing strategies.
The first system is an imaging Fourier-transform spectromter (IFTS) based on recording
a set of microbolometer camera frames of a sample’s response to illumination by uniquely
spectrally structured blackbody radiation from a Michelson interferometer. The developed
non-uniform sampling strategy was, to my knowledge, the first practical implementation of
compressive sensing in Fourier-transform spectroscopy and enabled a sampling rate as low as
15% Nyquist-limited sampling with a generic prior. The instrument was used in a campaign
at the Hunterian Museum on the artwork “Uplands in Lorne” by David Young Cameron.
A second system utilised a fast digital micromirror device (DMD) to arbitrarily shape
MIR spectra, providing sample illumination by optimised spectral structures for material
identification.
OCT has seen extensive work in the visible and near-infrared (NIR) but not as much
in the MIR. This is, in part, due to the limitation of suitable MIR ultrafast sources. MIR
OCT has the advantage of greater sample penetration depth which could find applications
in the security sector. Results are presented from an MIR time-domain OCT system with
an ultrafast orientation-patterned gallium phosphide (OP-GaP) optical parametric oscillator
(OPO)
Poiesis and Obstruction in Art Practice
No full textThis PhD thesis examines the concept of poiesis, that is ‘calling into existence that which was not there before’, in the context of obstruction in studio practice. It poses the question ‘Is there a methodology that engages with obstruction which in turn calls new work’? In this thesis, the concept of poiesis emerging from the late Dr. Murray Cox’s ‘Aeolian Mode’, is analyzed alongside a concept of praxis, (a philosophical companion to poiesis), familiar to artistic practice. This thesis describes the orientation of the original idea, The Aeolian Mode, clinically developed by Dr. Murray Cox in Broadmoor Psychiatric Hospital. This PhD seeks to identify if there are similar ‘tenets of approach’ held within the methodology of ‘The Aeolian Mode’, that would be useful or are identifiable in artistic studio practice. This thesis draws on the work of the philosopher, Professor Richard Kearney, specifically Kearney’s ideas on the necessity of ‘the other’ for ‘radical possibility’ to occur. It maps a context of both Freudian and Jungian interpretations of art practice, identifying how these ideas have shaped the way art is seen today. Furthermore, it challenges the Freudian idea of ‘pathography’ and favours a Jungian approach of ‘individuation’ in the understanding of creative processes. It develops a ‘methodology of the conversation’, interviewing students, established artists, tutors about their approaches to obstruction/poiesis in art practice. Additionally, it examines my own obstruction to painting and identifies the methodology that released me from this obstruction. Conducting these interviews on art practice has enabled me to confirm my initial concerns about Freudian ‘pathography’ whilst validating the possibility of the Jungian concept of ‘individuation’ being of use to art practice. Finally, this PhD discusses the implications for further study and research, which have emerged during the ‘methodology of the conversation’ and the task of dissolving my obstruction to painting
Using near misses to teach concepts to a human intelligence system
No full textThesis: M. Eng., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2018.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Cataloged from student-submitted PDF version of thesis.Includes bibliographical references (page 63).If we are to understand how we can build artificial intelligence machines that are able to organically process and acquire knowledge like humans do, we must first understand how to teach a human intelligence system to model and learn generic concepts without resorting to mechanistic hand-coding of such concepts. Such an achievement in human intelligence is an important stride towards the realization of Minsky's hypothetical "baby machine." Genesis is a story-understanding system that reads and analyzes stories in simple English, as humans do. Genesis can recognize certain sequences of events as particular manifestations of some user-defined concepts, such as revenge or physical retaliation. However, both the structure and definition of these high-level concepts must be explicitly provided by the user, and must be exactly matched using concept patterns against sequences of events in a story. I propose that this paradigm is unlike how humans learn such concepts, and instead, such concepts are learned by example, not by explicit definition. To introduce this organic, example-driven paradigm to Genesis, I have created STUDENT, a system that ingests a small series of positive and negative examples of concepts and builds an internal model for these concepts. By aligning similar examples of concepts together, I have constructed refined concept patterns which encompass multiple, different manifestations of the concepts, without requiring a human to explicitly define them. Adding this capability to Genesis enables it to learn concepts by example from a teacher. This behavior emulates how maturing humans learn concepts. Achieving this ability to emulate a human's learning process for a new idea brings us one step closer to modeling human intelligence and story understanding.by Jake A. Barnwell.M. Eng
The Need for Pet Fitness Facilities
No full textA business plan for a new pet fitness center and how these centers will help keep you and your pet fitFall 2013Accompanied by vide
A decade of astrocombs: recent advances in frequency combs for astronomy
No full textA new regime of precision radial-velocity measurements in the search for Earth-like exoplanets is being facilitated by high-resolution spectrographs calibrated by laser frequency combs. Here we review recent advances in the development of astrocomb technology, and discuss the state of the field going forward
PISTACHIO (Photonic Imaging Strategies For Technical Art History And Conservation)
No full textIR spectral database of artists’ pigments to be used as spectral library for compound identification purposes. Spectra were acquired using a benchtop FTIR microscope in ATR and external reflection, and the novel hyperspectral Fourier-transform spectrometer built within the PISTACHIO project, a collaboration between the University of Glasgow and Heriot-Watt University in Edinburgh
How does terrain influence the upscale convective growth of orographic deep moist convection?
No full textSatellite observations have revealed that some of the world’s most intense deep convective storms occur near the Sierras de Córdoba, Argentina, South America. A ground-based radar climatology during two austral spring and summer seasons (2015–2017) revealed that most of the storms were multicellular and initiated most frequently during the early afternoon and late evening hours just east of the Sierras de Córdoba. The peak occurrence of these storms was between December-February. Storm environments in Argentina tend to be characterized by larger convective available potential energy and weaker low-level vertical wind shear compared to the United States. One of the more intriguing results is the relatively fast transition, and close proximity to terrain, from first storms to larger mesoscale convective systems compared with locations in the United States.
A canonical upscale convective growth case was simulated with the Weather Research and Forecasting model to understand the role of topography in this transition process. This case featured an orographic supercell that transitioned into a bowing mesoscale convective system over three-to-four hours. The simulation revealed enhanced low-level vertical wind shear along the eastern slopes of the Sierras de Córdoba that aided in the formation of a left moving supercell. Shortly thereafter, strong downdrafts and expansion of the cold pool resulted in a rapid transition to a bowing mesoscale convective system. Terrain height sensitivity experiments were conducted with only the control and higher terrain experiments resulting in a supercell-to-bowing mesoscale convective system transition. The control simulation, with the real terrain of the Sierras de Córdoba, resulted in the faster upscale convective growth owing to both terrain-driven environmental and storm-scale effects, such as variations to thermodynamic/kinematic profiles and terrain blocking of cold pools, respectively.
Inspired by the aforementioned ground-based radar climatology and in-depth numerical modeling upscale convective growth case study in north central Argentina, a set of different initial terrain height idealized numerical modeling experiments were conducted. These experiments were devised to determine the relative roles of both direct and indirect influences of terrain on upscale convective growth of a supercell in a model configuration similar to those observed near the Sierras de Cόrdoba in Argentina. The experimental results indicated that when the terrain was systematically raised, convection initiation occurred earlier, supercells were wider and more intense, and upscale convective growth generally occurred faster. A direct influence of terrain was blocking of cold pools leading to a deepening of the cold pools that drove surging outflow and more rapid upscale convective growth. Indirect influences of terrain included modifications to the surrounding thermodynamic and kinematic profiles, with terrain-enhancements to the vertical wind shear profile prompting wider updrafts in higher terrain supercells. These wider supercell updrafts were accompanied by greater vertical mass flux, wider and stronger downdrafts, and deeper cold pools, promoting more rapid upscale convective growth.Submission published under a 24 month embargo labeled 'Closed Access', the embargo will last until 2021-08-01The student, Jake Mulholland, accepted the attached license on 2019-06-27 at 10:58.The student, Jake Mulholland, submitted this Dissertation for approval on 2019-06-27 at 11:07.This Dissertation was approved for publication on 2019-06-28 at 11:07.DSpace SAF Submission Ingestion Package generated from Vireo submission #14094 on 2019-11-26 at 14:00:29Made available in DSpace on 2019-11-26T20:58:34Z (GMT). No. of bitstreams: 4
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Previous issue date: 2019-06-28Embargo set by: Seth Robbins for item 113028
Lift date: 2021-11-26T20:58:44Z
Reason: Author requested closed access (OA after 2yrs) in Vireo ETD systemEmbargo set by: Seth Robbins for item 113028
Lift date: 2021-11-26T20:59:54Z
Reason: Author requested closed access (OA after 2yrs) in Vireo ETD systemLimited Restriction Lifted for Item 113028 on 2021-11-27T10:15:16Z
MOFDiff: Coarse-grained Diffusion for Metal-Organic Framework Design
No full text<p>This repository contains:</p>
<ul>
<li>bw_db.tar.gz: the preprocessed BW-DB dataset</li>
<li>pretrained.tar.gz: pretrained building block encoder and CG diffusion models</li>
<li>bb_emb_space.tar.gz: the building block embedding space</li>
</ul>
<p>described in the paper: "MOFDiff: Coarse-grained Diffusion for Metal-Organic Framework Design."</p>
<p>paper: https://arxiv.org/abs/2310.10732</p>
<p>code: https://github.com/microsoft/MOFDiff</p>
<p>If you find this repository useful, please consider reference in your paper:</p>
<pre><code>@inproceedings{
fu2024mofdiff,
title={{MOFD}iff: Coarse-grained Diffusion for Metal-Organic Framework Design},
author={Xiang Fu and Tian Xie and Andrew Scott Rosen and Tommi S. Jaakkola and Jake Allen Smith},
booktitle={The Twelfth International Conference on Learning Representations},
year={2024},
url={https://openreview.net/forum?id=0VBsoluxR2}
}<br><br>@article{boyd2019data,
title={Data-driven design of metal--organic frameworks for wet flue gas CO2 capture},
author={Boyd, Peter G and Chidambaram, Arunraj and Garc{\'\i}a-D{\'\i}ez, Enrique and Ireland, Christopher P and Daff, Thomas D and Bounds, Richard and G{\l}adysiak, Andrzej and Schouwink, Pascal and Moosavi, Seyed Mohamad and Maroto-Valer, M Mercedes and others},
journal={Nature},
volume={576},
number={7786},
pages={253--256},
year={2019},
publisher={Nature Publishing Group UK London}
}</code></pre>
<p> </p>
MOFDiff: Coarse-grained Diffusion for Metal-Organic Framework Design
No full text<p>This repository contains:</p>
<ul>
<li>bw_db.tar.gz: the preprocessed BW-DB dataset</li>
<li>pretrained.tar.gz: pretrained building block encoder and CG diffusion models</li>
<li>bb_emb_space.tar.gz: the building block embedding space</li>
<li>WC_optimized.tar.gz: MOF samples from MOFDiff that condition on a high CO2 working capacity. 2085 samples were valid, novel, and unique (VNU) from 10000 total samples.</li>
</ul>
<p>described in the paper: "MOFDiff: Coarse-grained Diffusion for Metal-Organic Framework Design."</p>
<p>paper: https://arxiv.org/abs/2310.10732</p>
<p>code: https://github.com/microsoft/MOFDiff</p>
<p>If you find this repository useful, please consider reference in your paper:</p>
<pre><code>@inproceedings{
fu2024mofdiff,
title={{MOFD}iff: Coarse-grained Diffusion for Metal-Organic Framework Design},
author={Xiang Fu and Tian Xie and Andrew Scott Rosen and Tommi S. Jaakkola and Jake Allen Smith},
booktitle={The Twelfth International Conference on Learning Representations},
year={2024},
url={https://openreview.net/forum?id=0VBsoluxR2}
}<br><br>@article{boyd2019data,
title={Data-driven design of metal--organic frameworks for wet flue gas CO2 capture},
author={Boyd, Peter G and Chidambaram, Arunraj and Garc{\'\i}a-D{\'\i}ez, Enrique and Ireland, Christopher P and Daff, Thomas D and Bounds, Richard and G{\l}adysiak, Andrzej and Schouwink, Pascal and Moosavi, Seyed Mohamad and Maroto-Valer, M Mercedes and others},
journal={Nature},
volume={576},
number={7786},
pages={253--256},
year={2019},
publisher={Nature Publishing Group UK London}
}</code></pre>
<p> </p>
- …
