180 research outputs found

    Transformer Networks for Trajectory Forecasting

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    Most recent successes on forecasting the people motion are based on LSTM models and all most recent progress has been achieved by modelling the social interaction among people and the people interaction with the scene. We question the use of the LSTM models and propose the novel use of Transformer Networks for trajectory forecasting. This is a fundamental switch from the sequential step-by-step processing of LSTMs to the only-attention-based memory mechanisms of Transformers. In particular, we consider both the original Transformer Network (TF) and the larger Bidirectional Transformer (BERT), state-of-the-art on all natural language processing tasks. Our proposed Transformers predict the trajectories of the individual people in the scene. These are "simple" model because each person is modelled separately without any complex human-human nor scene interaction terms. In particular, the TF model without bells and whistles yields the best score on the largest and most challenging trajectory forecasting benchmark of TrajNet. Additionally, its extension which predicts multiple plausible future trajectories performs on par with more engineered techniques on the 5 datasets of ETH + UCY. Finally, we show that Transformers may deal with missing observations, as it may be the case with real sensor data. Code is available at https://github.com/FGiuliari/Trajectory-Transformer.Comment: 18 pages, 3 figure

    The Spectrum of Fundus Autofluorescence Findings in Birdshot Chorioretinopathy

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    Objective. To describe the diverse patterns observed with the use of autofluorescence fundus photography (FAF) in patients with Birdshot chorioretinopathy (BSCR). Methods. A chart review of patients with BSCR seen at the Massachusetts Eye Research and Surgery Institution, who had autofluorescence fundus photography. The data obtained included age, gender, presence of the HLA-A29 haplotype, and current treatment. Results. Eighteen eyes with HLA-A29 associated BSCR were included. Four eyes presented with active inflammation. Correspondence of the lesions noted in the colour fundus photograph was observed in 3 eyes which were more easily identified with the FAF. Fifteen eyes had fundus lesions more numerous and evident in the FAF than in the colour fundus photograph. Conclusion. Because FAF testing provides valuable insight into the metabolic state of the PR/RPE-complex, it may serve as a useful noninvasive assessment tool in patients with posterior uveitis in which the outer retina-RPE-choriocapillaries-complex is involved

    GMA: A Pareto Optimal Distributed Resource-Allocation Algorithm

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    To address the rising demand for strong packet delivery guarantees in networking, we study a novel way to perform graph resource allocation. We first introduce allocation graphs, in which nodes can independently set local resource limits based on physical constraints or policy decisions. In this scenario we formalize the distributed path-allocation (PAdist) problem, which consists in allocating resources to paths considering only local on-path information -- importantly, not knowing which other paths could have an allocation -- while at the same time achieving the global property of never exceeding available resources. Our core contribution, the global myopic allocation (GMA) algorithm, is a solution to this problem. We prove that GMA can compute unconditional allocations for all paths on a graph, while never over-allocating resources. Further, we prove that GMA is Pareto optimal with respect to the allocation size, and it has linear complexity in the input size. Finally, we show with simulations that this theoretical result could be indeed applied to practical scenarios, as the resulting path allocations are large enough to fit the requirements of practically relevant applications

    Orbital Burkitt's Lymphoma: An Aggressive Presentation

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    Objective. To present the case of an aggressive orbital Burkitt's lymphoma. Methods. Chart review. Case Presentation. A 24-year-old Haitian man came to our clinic complaining of rapidly progressive right eye proptosis. On examination, a large friable exophytic mass with necrotic areas and exudative/hemorrhagic secretions was noted protruding from his right orbit. A biopsy revealed the characteristic “starry-sky” appearance of a Burkitt lymphoma. The patient died shortly after due to complications from systemic involvement. Discussion. This case is meant to raise physicians' awareness on the healthcare situation in some underdeveloped countries, emphasizing the importance of education in preventive medicine

    Presumed Sturge Weber Syndrome in a Haitian Boy: A Case of Delayed Diagnosis

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    Purpose. To report an untypical presentation of a presumed Sturge-Weber Syndrome (SWS), and to highlight the indispensable value of thorough clinical examination as primary means for proper diagnosis and management. Methods. Chart review. Results. A 7 year-old boy, with a long history of ocular symptoms and an unspecified ocular surgery, presents with a painful blind left eye. Based on clinical examination, the suspicion of SWS was raised. The presentation was not typical in the sense that no evident port-wine stain was observed on the face. However, facial asymmetry and gum discoloration were guiding clinical clues to pursue further investigations. Unfortunately, due to poor treatment response, the patient underwent enucleation. Tissue pathology revealed diffuse choroidal hemangiomas, consistent with the diagnosis of SWS. Conclusion. SWS presents with hamartomatous malformations and venous dilation affecting the skin, central nervous system and eye. The ocular involvement may vary, with the most common complications being glaucoma, buphthalmos and diffuse choroidal hemangiomas. This case report helps remind physicians of the importance of a thorough clinical examination, and highlights the ophthalmologists' responsibility of examining beyond the eye

    Leveraging commonsense for object localisation in partial scenes

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    We propose an end-to-end solution to address the problem of object localisation in partial scenes, where we aim to estimate the position of an object in an unknown area given only a partial 3D scan of the scene. We propose a novel scene representation to facilitate the geometric reasoning, Directed Spatial Commonsense Graph (D-SCG), a spatial scene graph that is enriched with additional concept nodes from a commonsense knowledge base. Specifically, the nodes of D-SCG represent the scene objects and the edges are their relative positions. Each object node is then connected via different commonsense relationships to a set of concept nodes. With the proposed graph-based scene representation, we estimate the unknown position of the target object using a Graph Neural Network that implements a novel attentional message passing mechanism. The network first predicts the relative positions between the target object and each visible object by learning a rich representation of the objects via aggregating both the object nodes and the concept nodes in D-SCG. These relative positions then are merged to obtain the final position. We evaluate our method using Partial ScanNet, improving the state-of-the-art by 5.9% in terms of the localisation accuracy at a 8x faster training speed.Comment: arXiv admin note: text overlap with arXiv:2203.0538

    Hummingbird: A Flexible and Lightweight Inter-Domain Bandwidth-Reservation System

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    The current Internet lacks a bandwidth-reservation infrastructure that enables fine-grained inter-domain reservations for end hosts. This is hindering the provisioning of quality-of-service guarantees for real-time applications like video calls and gaming, cloud-based systems, financial transactions, telesurgery, and other remote applications that benefit from reliable communication. This paper introduces Hummingbird, a novel lightweight inter-domain bandwidth-reservation system that addresses several shortcomings of previous designs. Hummingbird supports flexible and composable reservations and enables end-to-end guarantees without requiring autonomous systems to manage reservations for their endhosts. Previous systems tied reservations to autonomous-system numbers or network addresses, which limits the flexibility of reservations. In contrast, our system decouples reservations from network identities and, as a result, the control plane from the data plane. This design choice facilitates multiple co-existing control-plane mechanisms and enables innovative approaches, such as a control plane based on blockchain smart contracts that offers tradeable bandwidth-reservation assets and end-to-end guarantees. The data-plane design ensures simplicity for efficient processing on border routers, which streamlines implementation, deployment, and traffic policing while maintaining robust security properties.Comment: 14 pages, 7 figure
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