77 research outputs found

    Template-Cut: A Pattern-Based Segmentation Paradigm

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    We present a scale-invariant, template-based segmentation paradigm that sets up a graph and performs a graph cut to separate an object from the background. Typically graph-based schemes distribute the nodes of the graph uniformly and equidistantly on the image, and use a regularizer to bias the cut towards a particular shape. The strategy of uniform and equidistant nodes does not allow the cut to prefer more complex structures, especially when areas of the object are indistinguishable from the background. We propose a solution by introducing the concept of a "template shape" of the target object in which the nodes are sampled non-uniformly and non-equidistantly on the image. We evaluate it on 2D-images where the object's textures and backgrounds are similar, and large areas of the object have the same gray level appearance as the background. We also evaluate it in 3D on 60 brain tumor datasets for neurosurgical planning purposes.Comment: 8 pages, 6 figures, 3 tables, 6 equations, 51 reference

    Resentencing of Juvenile Lifers: The Philadelphia Experience

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    We examined the Philadelphia District Attorney Office’s approach to juvenile lifer resentencing, which began in 2017 under the administration of District Attorney Seth Williams and has continued under the administration of District Attorney Larry Krasner. For cases resentenced as of December 31st, 2019, we describe similarities and differences between the Williams and Krasner administrations in decision making and sentence length reductions, and we report on the recidivism rate and estimated cost savings for Pennsylvania as a result of release

    A First Look at the Plea Deal Experiences of Juveniles Tried in Adult Court

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    While there is a large body of research on the legal capacities of adolescents, this research largely has neglected the plea-deal context. To learn about adolescents’ understanding of the plea process and their appreciation of the short- and long-term consequences of accepting a plea deal, we conducted interviews with 40 juveniles who were offered plea deals in adult criminal court. Participants displayed a limited understanding of the plea process were not fully aware of their legal options and appeared to be overly influenced by the short-term benefits associated with accepting their plea deals. Limited contact with attorneys may have contributed to poor understanding. Although preliminary, our results suggest that these youth might be at increased risk for due-process rights violations. We use these data to point to several open research questions on the plea-deal process for youth charged as adults

    Model based three dimensional medical image segmentation

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    Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1999.Includes bibliographical references (leaves 115-123).by Tina Kapur.Ph.D

    Segmentation of Brain Tissue from Magnetic Resonance Images

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    Segmentation of medical imagery is a challenging problem due to the complexity of the images, as well as to the absence of models of the anatomy that fully capture the possible deformations in each structure. Brain tissue is a particularly complex structure, and its segmentation is an important step for studies in temporal change detection of morphology, as well as for 3D visualization in surgical planning. In this paper, we present a method for segmentation of brain tissue from magnetic resonance images that is a combination of three existing techniques from the Computer Vision literature: EM segmentation, binary morphology, and active contour models. Each of these techniques has been customized for the problem of brain tissue segmentation in a way that the resultant method is more robust than its components. Finally, we present the results of a parallel implementation of this method on IBM's supercomputer Power Visualization System for a database of 20 brain scans each with 256x256x124 voxels and validate those against segmentations generated by neuroanatomy experts

    Pituitary Adenoma Volumetry with 3D Slicer

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    In this study, we present pituitary adenoma volumetry using the free and open source medical image computing platform for biomedical research: (3D) Slicer. Volumetric changes in cerebral pathologies like pituitary adenomas are a critical factor in treatment decisions by physicians and in general the volume is acquired manually. Therefore, manual slice-by-slice segmentations in magnetic resonance imaging (MRI) data, which have been obtained at regular intervals, are performed. In contrast to this manual time consuming slice-by-slice segmentation process Slicer is an alternative which can be significantly faster and less user intensive. In this contribution, we compare pure manual segmentations of ten pituitary adenomas with semi-automatic segmentations under Slicer. Thus, physicians drew the boundaries completely manually on a slice-by-slice basis and performed a Slicer-enhanced segmentation using the competitive region-growing based module of Slicer named GrowCut. Results showed that the time and user effort required for GrowCut-based segmentations were on average about thirty percent less than the pure manual segmentations. Furthermore, we calculated the Dice Similarity Coefficient (DSC) between the manual and the Slicer-based segmentations to proof that the two are comparable yielding an average DSC of 81.97±3.39%

    We Don’t Always Mean What We Say: Attitudes Toward Statutory Exclusion of Juvenile Offenders From Juvenile Court Jurisdiction

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    In the United States, juvenile offenders are often excluded from the jurisdiction of the juvenile court on the basis of age and crime type alone. Data from national surveys and data from psycholegal research on support for adult sanction of juvenile offenders are often at odds. The ways in which questions are asked and the level of detail provided to respondents and research participants may influence expressed opinions. Respondents may also be more likely to agree with harsh sanctions when they have fewer offender- and case-specific details to consider. Here, we test the hypothesis that attitudes supporting statutory exclusion laws measured in the absence of specific case-specific details may not be the best indicator of agreement with such laws in practice. We found that support for statutory exclusion was affected by exposure to information about an offender’s unique situation and by exposure to general scientific information about adolescent development. These results suggest that despite an apparent widespread agreement with automatic exclusion statutes, laypersons consider factors other than those allowed by the law when they are asked how to treat an individual offender
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