52 research outputs found

    Spherical mask: coarse-to-fine 3D point cloud instance segmentation with spherical representation

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    Coarse-to-fine 3D instance segmentation methods show weak performances compared to recent Grouping-based Kernel-based and Transformer-based methods. We argue that this is due to two limitations: 1) Instance size overestimation by axis-aligned bounding box(AABB) 2) False negative error accumulation from inaccurate box to the refinement phase. In this work we introduce Spherical Mask a novel coarse-to-fine approach based on spherical representation overcoming those two limitations with several benefits. Specifically our coarse detection estimates each instance with a 3D polygon using a center and radial distance predictions which avoids excessive size estimation of AABB. To cut the error propagation in the existing coarse-to-fine approaches we virtually migrate points based on the polygon allowing all foreground points including false negatives to be refined. During inference the proposal and point migration modules run in parallel and are assembled to form binary masks of instances. We also introduce two margin-based losses for the point migration to enforce corrections for the false positives/negatives and cohesion of foreground points significantly improving the performance. Experimental results from three datasets such as ScanNetV2 S3DIS and STPLS3D show that our proposed method outperforms existing works demonstrating the effectiveness of the new instance representation with spherical coordinates. The code is available at: https://github.com/yunshin/SphericalMas

    Sample, crop, track: self-supervised mobile 3D object detectionfor urban driving LiDAR

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    Deep learning has led to great progress in the detection of mobile (i.e. movement-capable) objects in urban driving scenes in recent years. Supervised approaches typically require the annotation of large training sets; there has thus been great interest in leveraging weakly, semi- or selfsupervised methods to avoid this, with much success. Whilst weakly and semi-supervised methods require some annotation, self-supervised methods have used cues such as motion to relieve the need for annotation altogether. However, a complete absence of annotation typically degrades their performance, and ambiguities that arise during motion grouping can inhibit their ability to find accurate object boundaries. In this paper, we propose a new self-supervised mobile object detection approach called SCT. This uses both motion cues and expected object sizes to improve detection performance, and predicts a dense grid of 3D oriented bounding boxes to improve object discovery. We significantly outperform the state-of-the-art self-supervised mobile object detection method TCR on the KITTI tracking benchmark, and achieve performance that is within 30% of the fully supervised PV-RCNN++ method for IoUs ≤ 0.5. Our source code will be made available online

    DynPoint: Dynamic Neural Point For View Synthesis

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    The introduction of neural radiance fields has greatly improved the effectiveness of view synthesis for monocular videos. However, existing algorithms face difficulties when dealing with uncontrolled or lengthy scenarios, and require extensive training time specific to each new scenario. To tackle these limitations, we propose DynPoint, an algorithm designed to facilitate the rapid synthesis of novel views for unconstrained monocular videos. Rather than encoding the entirety of the scenario information into a latent representation, DynPoint concentrates on predicting the explicit 3D correspondence between neighboring frames to realize information aggregation. Specifically, this correspondence prediction is achieved through the estimation of consistent depth and scene flow information across frames. Subsequently, the acquired correspondence is utilized to aggregate information from multiple reference frames to a target frame, by constructing hierarchical neural point clouds. The resulting framework enables swift and accurate view synthesis for desired views of target frames. The experimental results obtained demonstrate the considerable acceleration of training time achieved - typically an order of magnitude - by our proposed method while yielding comparable outcomes compared to prior approaches. Furthermore, our method exhibits strong robustness in handling long-duration videos without learning a canonical representation of video content

    Relationships between 24-Hour Blood Pressures, Subcortical Ischemic Lesions, and Cognitive Impairment

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    Background and Purpose The most important treatment for subcortical vascular dementia (SVaD) is controlling the blood pressure (BP). However, the few studies that have investigated the relationships between diurnal BP rhythm and subcortical ischemic vascular cognitive impairment have produced inconclusive results. In the study presented here, the 24-hour BP values of three groups of subjects-patients with subcortical vascular mild cognitive impairment (SvMCI), patients with SVaD, and normal controls-were compared using working criteria and 24-hour ambulatory BP (ABP) monitoring. Methods The subjects (42 patients with SVaD, 37 patients with SvMCI, and 30 controls) were selected according to the Study`s inclusion/exclusion criteria. All subjects underwent brain magnetic resonance (MR) imaging and MR angiography, detailed neuropsychological testing, and 24-hour ABP monitoring. Results The prevalence of nondippers differed markedly between the control group and both the SVaD and SvMCI groups. Loss of nocturnal dipping was significantly associated with SVaD [odds ratio (OR), 4.827; 95% confidence interval (CI), 1.07-12.05]. Conclusions It was found that SVaD is associated with loss of nocturnal BP dipping combined with increased pulse pressure and systolic BP (SBP) variability. Correction of these factors could therefore be important in the prevention of SVaD, independent of measures used to reduce BP. J Clin Neurol 2009;5:139-145Ohmine T, 2008, HYPERTENS RES, V31, P75van Boxtel MPJ, 2006, J HUM HYPERTENS, V20, P5, DOI 10.1038/sj.jhh.1001934van der Flier WM, 2005, STROKE, V36, P2116Birns J, 2005, STROKE, V36, P1308, DOI 10.1161/01.STR.0000165901.38039.5fYamamoto Y, 2005, CEREBROVASC DIS, V19, P302, DOI 10.1159/000084498BOWLER JV, 2005, J NEUROL NEUROSUR S5, V76, P35KU HM, 2004, J KOREAN NEUROPSYCHI, V43, P189O`Brien E, 2003, J HYPERTENS, V21, P821, DOI 10.1097/01.hjh.0000059016.82022.caKANG Y, 2003, INCHEON HUMAN BRAINOhkubo T, 2002, J HYPERTENS, V20, P2183de Leeuw FE, 2002, BRAIN, V125, P765O`Brien JT, 2002, ANN NY ACAD SCI, V977, P436Kario K, 2001, HYPERTENSION, V38, P852Wahlund LO, 2001, STROKE, V32, P1318Dufouil C, 2001, NEUROLOGY, V56, P921Puisieux F, 2001, EUR NEUROL, V46, P115Staessen JA, 1999, JAMA-J AM MED ASSOC, V282, P539Swan GE, 1998, NEUROLOGY, V51, P986Blacher J, 1998, HYPERTENSION, V32, P570Cummings JL, 1998, J PSYCHOSOM RES, V44, P627Kilander L, 1998, HYPERTENSION, V31, P780Guo ZC, 1997, AM J EPIDEMIOL, V145, P1106Liao DP, 1996, STROKE, V27, P2262LAUNER LJ, 1995, JAMA-J AM MED ASSOC, V274, P1846YAMAMOTO Y, 1995, STROKE, V26, P829VERDECCHIA P, 1994, HYPERTENSION, V24, P793KUUSISTO J, 1993, HYPERTENSION, V22, P771SHIMADA K, 1992, J HYPERTENS, V10, P875SCHERR PA, 1991, AM J EPIDEMIOL, V134, P1303TOHGI H, 1991, STROKE, V22, P603OBRIEN E, 1988, LANCET, V2, P397PARATI G, 1987, J HYPERTENS, V5, P93HACHINSKI VC, 1975, ARCH NEUROL-CHICAGO, V32, P632

    Blood pressure and dementia risk by physical frailty in the elderly: a nationwide cohort study

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    Background Midlife hypertension has been recognized as a modifiable risk factor for dementia, but association between blood pressure (BP) in late life and dementia has been inconclusive. In addition, few studies have investigated effects of BP control on dementia incidence in the frail elderly. Thus, this study aimed to investigate the association of BP and dementia incidence with concomitant consideration of physical frailty in the young elderly population. Methods Using the Korean National Health Information Database, we identified 804,024 subjects without history of dementia at age 66. Dementia diagnosis was defined with prescription records of anti-dementia drugs and dementia-related diagnostic codes. Physical frailty was measured using the Timed Up and Go test. Association of BP and dementia incidence with concomitant consideration of physical frailty was investigated using Cox hazards analyses. Results The risks of Alzheimers and vascular dementia increased from systolic BP ≥ 160 and 130–139mmHg, respectively; a significant association of dementia incidence with low BP was not observed. In the analyses stratified by the physical frailty status, low BP was not associated with increased risks of dementia within the groups both with and without physical frailty. Conclusions High BP was associated with increased risks of dementia, especially for vascular dementia, while low BP was not associated with increased risks of any type of dementia in young elderly people, even in those with physical frailty. This study suggests the need for tight BP control in young elderly people, irrespective of frailty status, to prevent dementia and supports the current clinical guidelines of hypertension treatment

    Novel PSEN1 G209A mutation in early-onset Alzheimer dementia supported by structural prediction

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    This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.Abstract Background Three main genes are described as causative genes for early-onset Alzheimer dementia (EOAD): APP, PSEN1 and PSEN2. We describe a woman with EOAD had a novel PSEN1 mutation. Case report A 54-year-old right-handed woman presented 12-year history of progressive memory decline. She was clinically diagnosed as familial Alzheimer's disease due to a PSEN1 mutation. One of two daughters also has the same mutation, G209A in the TM-IV of PS1 protein. Her mother had unspecified dementia that began at the age of 40s. PolyPhen2 and SIFT prediction suggested that G209A might be a damaging variant with high scores. 3D modeling revealed that G209A exchange could result significant changes in the PS1 protein. Conclusion We report a case of EOAD having probable novel PSEN1 (G209A) mutation verified with structural prediction

    NICE 2023 Zero-shot Image Captioning Challenge

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    In this report, we introduce NICE project\footnote{\url{https://nice.lgresearch.ai/}} and share the results and outcomes of NICE challenge 2023. This project is designed to challenge the computer vision community to develop robust image captioning models that advance the state-of-the-art both in terms of accuracy and fairness. Through the challenge, the image captioning models were tested using a new evaluation dataset that includes a large variety of visual concepts from many domains. There was no specific training data provided for the challenge, and therefore the challenge entries were required to adapt to new types of image descriptions that had not been seen during training. This report includes information on the newly proposed NICE dataset, evaluation methods, challenge results, and technical details of top-ranking entries. We expect that the outcomes of the challenge will contribute to the improvement of AI models on various vision-language tasks.Comment: Tech report, project page https://nice.lgresearch.ai

    BIM-Based Maintenance Data Processing Mechanism through COBie Standard Development for Port Facility

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    In the AECO field, there have been many efforts to transform the design, construction, and maintenance methods that have been carried out in the traditional way based on document-based data into digital ones. BIM makes it possible for the information necessary for the entire construction process to be transformed into a language that computers can understand. In the field of architecture, BIM has been actively used throughout the entire construction life cycle through steady research since the 2000s, while COBie was developed in order to deliver information generated in the design and construction phase to the maintenance phase based on the BIM environment. In the field of infrastructure, however, digital data-based maintenance information management has not been actively studied. In particular, in the case of a port, once a facility is built, it has to be maintained for a longer period than other facilities, so facility maintenance is of utmost importance. Therefore, this study applied COBie, which is being used in the architecture field (building), to the port field. To this end, the COBie standard format in the port field was developed based on the port facility object breakdown structure and property breakdown structure. The port COBie developed through this study is included when the BIM model is converted to the IFC model so that facility management can be performed through the IFC-based viewer in the future. The port COBie schema developed in this study can be expanded to other fields such as roads and bridges in the future
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