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Search Results: 1 - 10 of 131700 matches for " William T. Freeman "
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Informative Sensing
Hyun Sung Chang,Yair Weiss,William T. Freeman
Mathematics , 2009,
Abstract: Compressed sensing is a recent set of mathematical results showing that sparse signals can be exactly reconstructed from a small number of linear measurements. Interestingly, for ideal sparse signals with no measurement noise, random measurements allow perfect reconstruction while measurements based on principal component analysis (PCA) or independent component analysis (ICA) do not. At the same time, for other signal and noise distributions, PCA and ICA can significantly outperform random projections in terms of enabling reconstruction from a small number of measurements. In this paper we ask: given the distribution of signals we wish to measure, what are the optimal set of linear projections for compressed sensing? We consider the problem of finding a small number of linear projections that are maximally informative about the signal. Formally, we use the InfoMax criterion and seek to maximize the mutual information between the signal, x, and the (possibly noisy) projection y=Wx. We show that in general the optimal projections are not the principal components of the data nor random projections, but rather a seemingly novel set of projections that capture what is still uncertain about the signal, given the knowledge of distribution. We present analytic solutions for certain special cases including natural images. In particular, for natural images, the near-optimal projections are bandwise random, i.e., incoherent to the sparse bases at a particular frequency band but with more weights on the low-frequencies, which has a physical relation to the multi-resolution representation of images.
Combined pergolide-associated valvular heart disease and achilles tendon contractures
William D. Freeman,Peter T. Dorsher,Robert E. Safford,Jay Van Gerpen
Acta Medica Academica , 2012,
Abstract: No abstract available.
Visually Indicated Sounds
Andrew Owens,Phillip Isola,Josh McDermott,Antonio Torralba,Edward H. Adelson,William T. Freeman
Computer Science , 2015,
Abstract: Materials make distinctive sounds when they are hit or scratched -- dirt makes a thud; ceramic makes a clink. These sounds reveal aspects of an object's material properties, as well as the force and motion of the physical interaction. In this paper, we introduce an algorithm that learns to synthesize sound from videos of people hitting objects with a drumstick. The algorithm uses a recurrent neural network to predict sound features from videos and then produces a waveform from these features with an example-based synthesis procedure. We demonstrate that the sounds generated by our model are realistic enough to fool participants in a "real or fake" psychophysical experiment, and that they convey significant information about the material properties in a scene.
Exploiting compositionality to explore a large space of model structures
Roger Grosse,Ruslan R Salakhutdinov,William T. Freeman,Joshua B. Tenenbaum
Computer Science , 2012,
Abstract: The recent proliferation of richly structured probabilistic models raises the question of how to automatically determine an appropriate model for a dataset. We investigate this question for a space of matrix decomposition models which can express a variety of widely used models from unsupervised learning. To enable model selection, we organize these models into a context-free grammar which generates a wide variety of structures through the compositional application of a few simple rules. We use our grammar to generically and efficiently infer latent components and estimate predictive likelihood for nearly 2500 structures using a small toolbox of reusable algorithms. Using a greedy search over our grammar, we automatically choose the decomposition structure from raw data by evaluating only a small fraction of all models. The proposed method typically finds the correct structure for synthetic data and backs off gracefully to simpler models under heavy noise. It learns sensible structures for datasets as diverse as image patches, motion capture, 20 Questions, and U.S. Senate votes, all using exactly the same code.
Computational Imaging for VLBI Image Reconstruction
Katherine L. Bouman,Michael D. Johnson,Daniel Zoran,Vincent L. Fish,Sheperd S. Doeleman,William T. Freeman
Computer Science , 2015,
Abstract: Very long baseline interferometry (VLBI) is a technique for imaging celestial radio emissions by simultaneously observing a source from telescopes distributed across Earth. The challenges in reconstructing images from fine angular resolution VLBI data are immense. The data is extremely sparse and noisy, thus requiring statistical image models such as those designed in the computer vision community. In this paper we present a novel Bayesian approach for VLBI image reconstruction. While other methods require careful tuning and parameter selection for different types of images, our method is robust and produces good results under different settings such as low SNR or extended emissions. The success of our method is demonstrated on realistic synthetic experiments as well as publicly available real data. We present this problem in a way that is accessible to members of the computer vision community, and provide a dataset website (vlbiimaging.csail.mit.edu) to allow for controlled comparisons across algorithms. This dataset can foster development of new methods by making VLBI easily approachable to computer vision researchers.
Administration of a tropomyosin receptor kinase inhibitor attenuates sarcoma-induced nerve sprouting, neuroma formation and bone cancer pain
Joseph R Ghilardi, Katie T Freeman, Juan M Jimenez-Andrade, William G Mantyh, Aaron P Bloom, Michael A Kuskowski, Patrick W Mantyh
Molecular Pain , 2010, DOI: 10.1186/1744-8069-6-87
Abstract: In the present report, we use a mouse model of bone cancer pain and examine whether oral administration of a selective small molecule Trk inhibitor (ARRY-470, which blocks TrkA, TrkB and TrkC kinase activity at low nm concentrations) has a significant effect on cancer-induced pain behaviors, tumor-induced remodeling of sensory nerve fibers, tumor growth and tumor-induced bone remodeling. Early/sustained (initiated day 6 post cancer cell injection), but not late/acute (initiated day 18 post cancer cell injection) administration of ARRY-470 markedly attenuated bone cancer pain and significantly blocked the ectopic sprouting of sensory nerve fibers and the formation of neuroma-like structures in the tumor bearing bone, but did not have a significant effect on tumor growth or bone remodeling.These data suggest that, like therapies that target the cancer itself, the earlier that the blockade of TrkA occurs, the more effective the control of cancer pain and the tumor-induced remodeling of sensory nerve fibers. Developing targeted therapies that relieve cancer pain without the side effects of current analgesics has the potential to significantly improve the quality of life and functional status of cancer patients.Cancer pain can have a significant impact on the quality of life and functional status of the individual [1,2]. A major reason cancer pain remains a significant health problem is the limited repertoire and negative side effects of currently available analgesics. For example, non-steroidal anti-inflammatory drugs, which are effective in reducing a variety of musculoskeletal pains, have been shown to have significant gastrointestinal side effects [3,4]. Opiates are also frequently used to treat moderate to severe cancer pain. While opiates are highly effective at controlling ongoing cancer pain, as a class opiates have a variety of unwanted side effects including increased somnolence, agitation, constipation, dizziness, cognitive impairment and respiratory depressio
A prospective trial of elective extubation in brain injured patients meeting extubation criteria for ventilatory support: a feasibility study
Edward M Manno, Alejandro A Rabinstein, Eelco FM Wijdicks, Allen W Brown, William D Freeman, Vivien H Lee, Stephen D Weigand, Mark T Keegan, Daniel R Brown, Francis X Whalen, Tuhin K Roy, Rolf D Hubmayr
Critical Care , 2008, DOI: 10.1186/cc7112
Abstract: Sixteen neurologically stable but severely brain injured patients with a Glasgow Coma Score (GCS) of 8 or less were randomised to early or delayed extubation until their neurological examination improved. Eligible patients met standard respiratory criteria for extubation and passed a modified Airway Care Score (ACS) to ensure adequate control of respiratory secretions. The primary outcome measured between groups was the functional status of the patient at hospital discharge as measured by a Modified Rankin Score (MRS) and Functional Independence Measure (FIM). Secondary measurements included the number of nosocomial pneumonias and re-intubations, and intensive care unit (ICU) and hospital length of stay. Standard statistical assessments were employed for analysis.Five female and eleven male patients ranging in age from 30 to 93 years were enrolled. Aetiologies responsible for the neurological injury included six head traumas, three brain tumours, two intracerebral haemorrhages, two subarachnoid haemorrhages and three ischaemic strokes. There were no demographic differences between the groups. There were no unexpected deaths and no significant differences in secondary measures. The difference in means between the MRS and FIM were small (0.25 and 5.62, respectively). These results suggest that between 64 and 110 patients are needed in each treatment arm to detect a treatment effect with 80% power.Recruitment and randomisation of severely brain injured patients appears to be safe and feasible. A large multicentre trial will be needed to determine if stable, severely brain injured patients who meet respiratory and airway control criteria for extubation need to remain intubated.More than 200,000 patients per year require mechanical ventilation primarily for neurological reasons based on rates of endotracheal intubation for patients with ischaemic and haemorrhagic stroke, head trauma and subarachnoid haemorrhage [1-6]. The direct and indirect costs of caring for head trau
Imaging an Event Horizon: Mitigation of Scattering Toward Sagittarius A*
Vincent L. Fish,Michael D. Johnson,Ru-Sen Lu,Sheperd S. Doeleman,Katherine L. Bouman,Daniel Zoran,William T. Freeman,Dimitrios Psaltis,Ramesh Narayan,Victor Pankratius,Avery E. Broderick,Carl R. Gwinn,Laura E. Vertatschitsch
Physics , 2014, DOI: 10.1088/0004-637X/795/2/134
Abstract: The image of the emission surrounding the black hole in the center of the Milky Way is predicted to exhibit the imprint of general relativistic (GR) effects, including the existence of a shadow feature and a photon ring of diameter ~50 microarcseconds. Structure on these scales can be resolved by millimeter-wavelength very long baseline interferometry (VLBI). However, strong-field GR features of interest will be blurred at lambda >= 1.3 mm due to scattering by interstellar electrons. The scattering properties are well understood over most of the relevant range of baseline lengths, suggesting that the scattering may be (mostly) invertible. We simulate observations of a model image of Sgr A* and demonstrate that the effects of scattering can indeed be mitigated by correcting the visibilities before reconstructing the image. This technique is also applicable to Sgr A* at longer wavelengths.
Is Peritoneal Cytology a Prognostic Factor in Endometrial Cancer?  [PDF]
Jonathan Foote, William T. Creasman
Journal of Cancer Therapy (JCT) , 2015, DOI: 10.4236/jct.2015.68073
Abstract: The International Federation of Gynecology and Obstetrics (FIGO) changed the surgical staging criteria for endometrial cancer in 2009, namely combining FIGO 1988 Stage IA and IB in FIGO 2009 Stage IA, eliminating cervical glandular involvement from Stage II, and removing peritoneal cytology as criteria from Stage IIIA (3). This review of the literature sheds light on the continued debate among authorities on the utility of peritoneal cytology in surgical staging of endometrial cancer. At the time FIGO removed peritoneal cytology from the staging criteria in 2009, there was little to no evidence to support its removal. In fact, FIGO continues to recommend obtaining peritoneal cytology, which is in contradiction to their staging criteria. While a few small studies support the idea that peritoneal cytology does not preclude a worse prognosis, a number of large scale studies with at least 300 patients demonstrate a clear association between survival and the presence of malignant peritoneal cytology (11 - 12, 15 - 19). In one of the largest studies, investigators reviewed 14,704 from the SEER’s database, demonstrating that malignant peritoneal cytology is associated with decreased survival across Stage I/II disease even when controlled for histology, grade, and other risk factors. Malignant peritoneal cytology should be considered when counseling patients on the risk of recurrence and overall survival of endometrial cancer. However, the role of adjuvant treatment in this setting remains unclear.
Apolipoprotein E decreases tau kinases and phospho-tau levels in primary neurons
Hyang-Sook Hoe, Jacob Freeman, G William Rebeck
Molecular Neurodegeneration , 2006, DOI: 10.1186/1750-1326-1-18
Abstract: Alzheimer's disease (AD) is defined neuropathologically by the presence of two types of protein aggregates: extracellular senile plaques, which are composed of the Aβ peptide, and intraneuronal neurofibrillary tangles (NFT), which are composed of phosphorylated forms of the tau protein [1-3]. Tau is a microtubule-associated protein with multiple phosphorylation sites [4]; hyperphosphorylation of tau in the AD brain is potentially promoted by several kinases, including GSK 3β, CDK5, and MARK [5]. Much AD-related research focuses on identifying factors that affect these neuropathological lesions and the risk of AD. One genetic factor that has been identified is the APOE genotype [6]. The APOE e4 allele is associated with increased Aβ deposition in brain [7-9]; evidence on whether APOE genotype also affects the accumulation of neurofibrillary tangles is more mixed [10].The apoE protein is associated with high-density lipoproteins in the CNS [11], and is increased after several types of brain damage [12,13]. ApoE-lipoproteins bind members of the low-density lipoprotein (LDL) receptor family [14], receptors with complex ligand binding domains that allow interactions with large numbers of ligands. These receptors mediate uptake of apoE-containing lipoproteins, suggesting that apoE receptors could be important in the clearance of lipids after damage [15]. But stimulation of these receptors by ligands also mediates various neuronal signaling mechanisms. Binding of Reelin to LDL receptor family members promotes phosphorylation of the cytoplasmic disabled protein (Dab1) [16], and induces activation of Src and PKB kinases [17,18]. These processes are necessary for correct neuronal migration during development. Furthermore, Reelin inhibits phosphorylation of GSK 3β, but does not affect the activity of CDK5 [19]. We have found that apoE binding to these receptors also promotes Dab phosphorylation and stimulates intracellular activation of Src and PKB kinase [20]; it is unknown w
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