144 research outputs found
Perceptual decisions under risk in a motion extrapolation paradigm:
No full textClassical work on decision-making has demonstrated systematic deviations from normative behavior. Recent experiments on movement planning, however, have shown that subjects can be indistinguishable from optimality in their visuo-motor decisions (Trommershaeuser et al., 2003a, 2003b). Unlike the classical case, the uncertainty in the visuo-motor case is internal to the subjects; it arises from their motor
variability—variability in executing a motor action.
We asked whether observers can also combine the intrinsic variability in their perceptual representation with externally-specified reward-and-penalty structure to make optimal decisions. We extended a paradigm used to study the visual extrapolation of static contour geometry (Singh & Fulvio, 2005), to examine observers’ decisions under risk in extrapolating curved motion trajectories.
Observers viewed a dot moving along a parabolic trajectory disappear behind the straight-edge of a half-disk occluder. Their task was to “catch” the dot from the opposite curved side, by adjusting the angular position of an arc or “mitt”. In the risky conditions, a double-mitt was used, comprising a green reward region and a red penalty region, with partial overlap.
Observers’ gains/losses were determined by the part of the double-mitt that “caught” the dot. Variables manipulated were: trajectory curvature, penalty value, and mitt overlap.
Observers’ performance in the baseline condition was used to estimate individual bias and variability. Based on these, predictions of optimal shift and optimal score were computed, using maximization of expected gain.
We found that observed shifts were well predicted by optimal shifts. Moreover, observer efficiency (observed/optimal score) was high (80% - 114%). The results indicate that observers are implicitly aware of the instrinsic variability in their perceptual representation, and can combine it with externally-specified reward-and-penalty structure to make near-
optimal decisions.M.S.Includes bibliographical references (p. 49-50)by Shalin Sha
Breaking into the Fulcrum Arena: A Concept Paper Looking Beyond Next Generation LMS
No full textIn the spirit of futurist probes into what a nextgen
learning management system (LMS)
may look like, the author uses a scifi
scenario to touch on some distant possibilities.
This fictional work follows J4 in his quest to break into the Fulcrum Arena and emerge
with the information and strategic relationships he needs to achieve mysterious aims.
This story envisions a learning space that integrates various databases, global
positioning systems (GPS), and other technologies into an integrated digital enclosure. It
focuses on informational elites, those who have the rawest and freshest information, vs.
those who get processed versions through public channels. Here, identities are
persistent and coalesced through information collected by ‘bots. The learning is all
strategic, it’s immersive, and it directly applies to the lived world
Josh Stock: Awesomeness Expert, and the delicious joys of teaching middle school
No full textJosh Stock, author of “Awesome Sauce,” talks about his work and how he motivates his students. He also shares insights about teaching in the time of the COVID-19 pandemic and lessons learned. The Q&A was codesigned by Shalin Hai-Jew and April Robbs
Virtual staining and segmentation of nuclei and membrane from quantitative phase
No full text<p>These models are used to analyze the data reported in the following preprint:<br><strong>Mantis: high-throughput 4D imaging and analysis of the molecular and physical architecture of cells</strong></p>
<p>The virtual staining models predict nuclei and cell membranes from quantitative phase images. The quantitative phase images are computed from the defocused transmitted light microscopy stacks using <a href="https://github.com/mehta-lab/recOrder" target="_blank" rel="noopener">recOrder</a>. <br><br>The predicted nuclei and membrane can be segmented with a variety of instance segmentation models. We share CellPose models for the segmentation of nuclei and cell membranes.</p>
<h2>Virtual Staining</h2>
<p>Make a new python environment and install the version of VisCy (v0.1.0a0) used for the mantis preprint.<br>For a detailed installation guide, see the <a href="https://github.com/mehta-lab/VisCy/blob/v0.1.0a0/README.md#installing-viscy">GitHub repository</a>.</p>
<p><br><code># This will also install Cellpose</code><br><code>pip install "viscy[metrics] @ git+https://github.com/mehta-lab/[email protected]"</code></p>
<p>Run inference of cell nuclei and plasma membrane by modifying the input and output Zarr store paths in <code>./viscy_model/predict.yml</code>.<br>See the <a href="https://github.com/mehta-lab/VisCy/blob/v0.1.0a0/docs/usage.md" target="_blank" rel="noopener">usage guide</a> in the repository.</p>
<h2>Segmentation</h2>
<p>To segment nuclei with our fine-tuned Cellpose model, use the following Python snippet:</p>
<p><br><code>from cellpose.models import CellposeModel</code><br><code>model = CellposeModel(model_type="./cellpose_model/CP_20220902_NuclFL")</code><br><code>segments = model.eval(...)</code><br><br></p>
<p>Refer to the <a href="https://cellpose.readthedocs.io/">Cellpose documentation</a> for API/GUI usage.</p>
Chinese MBS pricing model
No full textThesis: S.M. in Real Estate Development, Massachusetts Institute of Technology, Program in Real Estate Development in conjunction with the Center for Real Estate, 2017.Cataloged from PDF version of thesis.Includes bibliographical references (page 65).When it comes to financial innovations, Mortgage Backed Security (MBS) has the advantages of scattering risk, increasing liquidity, and lowering the financing costs. However, there are a few obstacles to developing a mature MBS market, among which the pricing of MBS is the vital one. Reasonable pricing will not only lead to the success of MBS issuance, but also pave the way for the China's MBS development in the future. This paper first introduced the definitions and development of MBS, and reviewed studies on the Subprime Crisis from the MBS prospective. This paper then discussed the MBS products, issuance procedures, and pricing principles. In particular, it analyzed the key factors of MBS pricing which affected the cash flow of MBS, and the methods to calculate the cash flow considering prepayment behavior. Based on China's capital market and the differences between Chinese and American capital markets and residential loan markets, this paper explored the appropriate pricing model for China's MBS market, and selected Static Cash Flow Yield method to price the MBS products in China. A simulation case was priced using SCFY. In the final section, the author gave some predictions about the development of MBS in China, including improving the primary and secondary mortgage market and the intermediary service system, and furthering interest rates liberalization.by Shalin Chen.S.M. in Real Estate Developmen
Image simulation for biological microscopy : microlith
No full textAuthor Posting. © Optical Society, 2014. This article is posted here by permission of Optical Society for personal use, not for redistribution. The definitive version was published in Biomedical Optics Express 5 (2014): 1822-1838, doi:10.1364/BOE.5.001822.Image simulation remains under-exploited for the most widely used biological phase microscopy methods, because of difficulties in simulating partially coherent illumination. We describe an open-source toolbox, microlith (https://code.google.com/p/microlith), which accurately predicts three-dimensional images of a thin specimen observed with any partially coherent imaging system, as well as images of coherently illuminated and self-luminous incoherent specimens. Its accuracy is demonstrated by comparing simulated and experimental bright-field and dark-field images of well-characterized amplitude and phase targets, respectively. The comparison provides new insights about the sensitivity of the dark-field microscope to mass distributions in isolated or periodic specimens at the length-scale of 10nm. Based on predictions using microlith, we propose a novel approach for detecting nanoscale structural changes in a beating axoneme using a dark-field microscope.This study was funded by National Institutes of Health grant RO1 EB00258
Dataset for demonstration of quantitative label-free imaging with phase and polarization
No full textThe QLIPP_Reconstruction_Resources_20x.zip file contains raw images of mouse brain slice and anisotropic glass target acquired with QLIPP. The file also contains the configuration files to reconstruct the phase, retardance, and orientation from this data with the recOrder pipeline. The tutorial slides for using this dataset for reconstruction can be found here (10.5281/zenodo.5135889).
v1.1.0: Upload two zip files for automated testing of recOrder and waveOrder repositories.
v1.2.0: add pycromanager dataset for testing the reader and converter in waveOrder.
v1.3.0: reduce the size of recOrder test datase
Polarized light imaging of birefringence and diattenuation at high resolution and high sensitivity
No full textAuthor Posting. © The Author(s), 2013. This is the author's version of the work. It is posted here by permission of IOP Publishing for personal use, not for redistribution. The definitive version was published in Journal of Optics 15 (2013): 094007, doi:10.1088/2040-8978/15/9/094007.Polarized light microscopy provides unique opportunities for analyzing the molecular order in manmade
and natural materials, including biological structures inside living cells, tissues, and whole organisms.
20 years ago, the LC-PolScope was introduced as a modern version of the traditional polarizing
microscope enhanced by liquid crystal devices for the control of polarization, and by electronic imaging
and digital image processing for fast and comprehensive image acquisition and analysis. The LCPolScope
is commonly used for birefringence imaging, analyzing the spatial and temporal variations of
the differential phase delay in ordered and transparent materials. Here we describe an alternative use of
the LC-PolScope for imaging the polarization dependent transmittance of dichroic materials. We explain
the minor changes needed to convert the instrument between the two imaging modes, discuss the relationship
between the quantities measured with either instrument, and touch on the physical connection
between refractive index, birefringence, transmittance, diattenuation, and dichroism.This work was supported by a fellowship of the Human Frontiers Science Program awarded to SM and a
grant from the National Institute of Biomedical Imaging and Bioengineering (grant Nr. R01EB002045)
awarded to RO. MS acknowledges support from the National Institute of General Medical Sciences/NIH
(grant R01-GM101701).2014-09-1
CCS Networks for the UK: Benefits, Impacts and Regulation
No full text18.09.12 KB. Published version, ok to add to spiral, author (B. Oraee-Mirzamani) says that copyright with both conference organisers and authors. Also asked permission of co-authors.What benefits might be offered by developing well planned CCS networks? A review of the drivers for and barriers to the coherent development of CCS networks in the UK is used to synthesise a limited set of possible network topologies. The benefits offered by each topology for UK carbon dioxide and other atmospheric emissions are estimated. Other potential benefits are considered qualitatively, and a range of uncertainties identified. The complexity of CCS networks means that addressing these uncertainties is a challenging task, and the need for a whole systems approach is evaluated. Finally, implications for CCS regulation and policy are highlighted
Tutorial on quantitative label-free imaging with phase and polarization (QLIPP) and demonstration of the calibration, acquisition and reconstruction software (recOrder).
No full textThis upload contains slides for the tutorial and the software demonstration.This research is supported by Chan Zuckerberg Biohub
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