737 research outputs found
Optimal Order of Decoding for Max-Min Fairness in -User Memoryless Interference Channels
A -user memoryless interference channel is considered where each receiver
sequentially decodes the data of a subset of transmitters before it decodes the
data of the designated transmitter. Therefore, the data rate of each
transmitter depends on (i) the subset of receivers which decode the data of
that transmitter, (ii) the decoding order, employed at each of these receivers.
In this paper, a greedy algorithm is developed to find the users which are
decoded at each receiver and the corresponding decoding order such that the
minimum rate of the users is maximized. It is proven that the proposed
algorithm is optimal.Comment: 11 Pages, Submitted to IEEE International Symposium on Information
Theory(ISIT 2007
Tunability of terahertz random lasers with temperature based on superconducting materials
We theoretically demonstrate the tunabiltiy of terahertz random lasers composed of high temperature superconductorYBCO and ruby layers as active medium. The considered system is a one-dimensional disordered medium made of ruby grain and YBCO. Finite-difference time domain method is used to calculate the emission spectrum and spatial distribution of electric field at different temperatures. Our numerical results reveal that the superconductor based random lasers exhibit large temperature tunability in the terahertz domain. The emission spectrum is significantly temperature dependent, the number of lasing modes and their intensities increase with decreasing temperature. Also, we make some discussion to explain the reason for the observed tunability and the effect of temperature variation on the spatial distribution of the electric field in the disordered active medium
Locating Emergency Facilities Using the Weighted k-median Problem: A Graph-metaheuristic Approach
An efficient approach is presented for addressing the problem of finding the optimal facilities location in conjunction with the k-median method. First the region to be investigated is meshed and an incidence graph is constructed to obtain connectivity properties of meshes. Then shortest route trees (SRTs) are rooted from nodes of the generated graph. Subsequently, in order to divide the nodes of graph or the studied region into optimal k subregions, k-median approach is utilized. The weights of the nodes are considered as the risk factors such as population, seismic and topographic conditions for locating facilities in the high-risk zones to better facilitation. For finding the optimal facility locations, a recently developed meta-heuristic algorithm that is called Colliding Bodies Optimization (CBO) is used. The performance of the proposed method is investigated through different alternatives for minimizing the cost of the weighted k-median problem. As a case study, the Mazandaran province in Iran is considered and the above graph-metaheuristic approach is utilized for locating the facilities
COVID-19 in pediatric patients: A case series
The COVID-19 pandemic outbreak has affected the global health system with an urgent need for more sophisticated studies.Ā One of the prominent aspects of COVID-19 is the picture of the disease in pediatric population. Our case series study includes 4 Babyboy patients in a referral children's hospital with different clinical outcomes
PARIS: Part-level Reconstruction and Motion Analysis for Articulated Objects
We address the task of simultaneous part-level reconstruction and motion
parameter estimation for articulated objects. Given two sets of multi-view
images of an object in two static articulation states, we decouple the movable
part from the static part and reconstruct shape and appearance while predicting
the motion parameters. To tackle this problem, we present PARIS: a
self-supervised, end-to-end architecture that learns part-level implicit shape
and appearance models and optimizes motion parameters jointly without any 3D
supervision, motion, or semantic annotation. Our experiments show that our
method generalizes better across object categories, and outperforms baselines
and prior work that are given 3D point clouds as input. Our approach improves
reconstruction relative to state-of-the-art baselines with a Chamfer-L1
distance reduction of 3.94 (45.2%) for objects and 26.79 (84.5%) for parts, and
achieves 5% error rate for motion estimation across 10 object categories.
Video summary at: https://youtu.be/tDSrROPCgUcComment: Presented at ICCV 2023. Project website:
https://3dlg-hcvc.github.io/paris
DAHiTrA: Damage Assessment Using a Novel Hierarchical Transformer Architecture
This paper presents DAHiTrA, a novel deep-learning model with hierarchical
transformers to classify building damages based on satellite images in the
aftermath of hurricanes. An automated building damage assessment provides
critical information for decision making and resource allocation for rapid
emergency response. Satellite imagery provides real-time, high-coverage
information and offers opportunities to inform large-scale post-disaster
building damage assessment. In addition, deep-learning methods have shown to be
promising in classifying building damage. In this work, a novel
transformer-based network is proposed for assessing building damage. This
network leverages hierarchical spatial features of multiple resolutions and
captures temporal difference in the feature domain after applying a transformer
encoder on the spatial features. The proposed network achieves
state-of-the-art-performance when tested on a large-scale disaster damage
dataset (xBD) for building localization and damage classification, as well as
on LEVIR-CD dataset for change detection tasks. In addition, we introduce a new
high-resolution satellite imagery dataset, Ida-BD (related to the 2021
Hurricane Ida in Louisiana in 2021, for domain adaptation to further evaluate
the capability of the model to be applied to newly damaged areas with scarce
data. The domain adaptation results indicate that the proposed model can be
adapted to a new event with only limited fine-tuning. Hence, the proposed model
advances the current state of the art through better performance and domain
adaptation. Also, Ida-BD provides a higher-resolution annotated dataset for
future studies in this field
Optimal Design of the Monopole Structures Using the CBO and ECBO Algorithms
Tubular steel monopole structure is widely used for supporting antennas in telecommunication industries. This research presents two recently developed meta-heuristic algorithms, which are called Colliding Bodies Optimization (CBO) and Enhanced Colliding Bodies Optimization (ECBO), for size optimization of monopole steel structures. The design procedure aims to obtain minimum weight of monopole structures subjected to the TIA-EIA222F speciļ¬cation. Two monopole structure examples are examined to verify the suitability of the design procedure and to demonstrate the effectiveness and robustness of the CBO and ECBO in creating optimal design for this problem. The outcomes of the enhanced colliding bodies optimization (ECBO) are also compared to those of the standard colliding bodies optimization (CBO) to illustrate the importance of the enhancement of the CBO algorithm
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