1,894 research outputs found
Cross layer designs for OFDMA wireless systems with heterogeneous delay requirements
This paper investigates a cross layer scheduling scheme for OFDMA wireless system with heterogeneous delay requirements. Unlike most existing cross layer designs which take a decoupling approach, our design considers both queueing theory and information theory in modeling the system dynamics. The cross layer design is formulated as an optimization of total system throughput, subject to individual user's delay constraint and total base station transmit power constraint. The optimal scheduling algorithm for the delay-sensitive cross layer optimization is to dynamically allocate radio resources based on users' channel state information, source statistics and delay requirements. Specifically, optimal power allocation was found to be multilevel water-filling where urgent users have higher water-filling levels, while optimal subcarrier allocation strategy is shown to be achievable by low complexity greedy algorithm. Simulation results also show the proposed jointly optimal power and subcarrier allocation policy can provide substantial throughput gain with all delay constraints being satisfied. © 2006 IEEE.published_or_final_versio
Cross-layer design for OFDMA wireless systems with heterogeneous delay requirements
This paper proposes a cross-layer scheduling scheme for OFDMA wireless systems with heterogeneous delay requirements. We shall focus on the cross-layer design which takes into account both queueing theory and information theory in modeling the system dynamics. We propose a delay-sensitive cross-layer design, which determines the optimal subcarrier allocation and power allocation policies to maximize the total system throughput, subject to the individual user's delay constraint and total base station transmit power constraint. The delay-sensitive power allocation was found to be multilevel water-filling in which urgent users have higher water-filling levels. The delay-sensitive subcarrier allocation strategy has linear complexity with respect to number of users and number of subcarriers. Simulation results show that substantial throughput gain is obtained while satisfying the delay constraints when the delay-sensitive jointly optimal power and subcarrier allocation policy is adopted. © 2007 IEEE.published_or_final_versio
Streptokinase is ineffective in restoring early myocardial reperfusion in Asian patients with acute myocardial infarction
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Concomitant plasmacytoma and B cell lymphoma with discordant light chain expression but clonal identity
Letter to the editorpublished_or_final_versionSpringer Open Choice, 25 May 201
Working memory impairment and its associated sleep-related respiratory parameters in children with obstructive sleep apnea
Study Objective: Working memory deficits in children with obstructive sleep apnea (OSA) have been reported in previous studies, but the results were inconclusive. This study tried to address this issue by delineating working memory functions into executive processes and storage/maintenance components based on Baddeley’s working memory model. Methods: Working memory and basic attention tasks were administered on 23 OSA children aged 8–12 years and 22 age-, education-, and general cognitive functioning-matched controls. Data on overnight polysomnographic sleep study and working memory functions were compared between the two groups. Associations between respiratory-related parameters and cognitive performance were explored in the OSA group. Results: Compared with controls, children with OSA had poorer performance on both tasks of basic storage and central executive components in the verbal domain of working memory, above and beyond basic attention and processing speed impairments; such differences were not significant in the visuo-spatial domain. Moreover, correlational analyses and hierarchical regression analyses further suggested that obstructive apnea–hypopnea index (OAHI) and oxygen saturation (SpO2) nadir were associated with verbal working memory performance, highlighting the potential pathophysiological mechanisms of OSA induced cognitive deficits. Conclusions: Verbal working memory impairments associated with OSA may compromise children’s learning potentials and neurocognitive development. Early identification of OSA and assessment of the associated neurocognitive deficits are of paramount importance. Reversibility of cognitive deficits after treatment would be a critical outcome indicatorpostprin
Lighting up NeRF via Unsupervised Decomposition and Enhancement
Neural Radiance Field (NeRF) is a promising approach for synthesizing novel
views, given a set of images and the corresponding camera poses of a scene.
However, images photographed from a low-light scene can hardly be used to train
a NeRF model to produce high-quality results, due to their low pixel
intensities, heavy noise, and color distortion. Combining existing low-light
image enhancement methods with NeRF methods also does not work well due to the
view inconsistency caused by the individual 2D enhancement process. In this
paper, we propose a novel approach, called Low-Light NeRF (or LLNeRF), to
enhance the scene representation and synthesize normal-light novel views
directly from sRGB low-light images in an unsupervised manner. The core of our
approach is a decomposition of radiance field learning, which allows us to
enhance the illumination, reduce noise and correct the distorted colors jointly
with the NeRF optimization process. Our method is able to produce novel view
images with proper lighting and vivid colors and details, given a collection of
camera-finished low dynamic range (8-bits/channel) images from a low-light
scene. Experiments demonstrate that our method outperforms existing low-light
enhancement methods and NeRF methods.Comment: ICCV 2023. Project website: https://whyy.site/paper/llner
Carcinoid tumour of the kidney in a Chinese woman presenting with loin pain
Renal carcinoid tumours are uncommon. The aetiology is not yet fully understood and there is still no useful diagnostic tool for detecting them. We report our experience managing a Chinese woman with a primary renal carcinoid tumour.published_or_final_versio
The use of enoxaparin in Chinese patients undergoing percutaneous coronary intervention: observations on safety, efficacy, and pharmacokinetics from a pilot study
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Percutaneous angioplasty and stenting as an alternative to surgery in the treatment of renal artery stenosis
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In-hospital and long-term clinical outcome following percutaneous transluminal coronary angioplasty in octogenarians
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