12,303 research outputs found
Low-Complexity Non-uniform Constellation Demapping Algorithm for Broadcasting System
This paper presents a novel low-complexity soft demapping algorithm for two-dimensional non-uniform spaced constellations (2D-NUCs) and massive order one-dimensional NUCs (1D-NUCs). NUCs have been implemented in a wide range of new broadcasting systems to approach the Shannon limit further, such as DVB-NGH, ATSC 3.0 and NGB-W. However, the soft demapping complexity is extreme due to the substantial distance calculations. In the proposed scheme, the demapping process is classified into four cases based on different quadrants. To deal with the complexity problem, four groups of reduced subsets in terms of the quadrant for each bit are separately calculated and stored in advance. Analysis and simulation prove that the proposed demapper only introduces a small penalty under 0.02dB with respect to Max-Log-MAP demapper, whereas a significant complexity reduction ranging from 68.75\% to 88.54\% is obtained
Clinical Features and Genetic Analysis of 20 Chinese Patients with X-Linked Hyper-IgM Syndrome
X-linked hyper-IgM syndrome (XHIGM) is one type of primary immunodeficiency diseases, resulting from defects in the CD40 ligand/CD40 signaling pathways. We retrospectively analyzed the clinical and molecular features of 20 Chinese patients diagnosed and followed up in hospitals affiliated to Shanghai Jiao Tong University School of Medicine from 1999 to 2013. The median onset age of these patients was 8.5 months (range: 20 days–21 months). Half of them had positive family histories, with a shorter diagnosis lag. The most common symptoms were recurrent sinopulmonary infections (18 patients, 90%), neutropenia (14 patients, 70%), oral ulcer (13 patients, 65%), and protracted diarrhea (13 patients, 65%). Six patients had BCGitis. Six patients received hematopoietic stem cell transplantations and four of them had immune reconstructions and clinical remissions. Eighteen unique mutations in CD40L gene were identified in these 20 patients from 19 unrelated families, with 12 novel mutations. We compared with reported mutation results and used bioinformatics software to predict the effects of mutations on the target protein. These mutations reflected the heterogeneity of CD40L gene and expanded our understanding of XHIGM
An immersed boundary method for the fluid--structure--thermal interaction in rarefied gas flow
An immersed boundary method for the fluid--structure--thermal interaction in
rarefied gas flow is presented. In this method, the slip model is incorporated
with the penalty immersed boundary method to address the velocity and
temperature jump conditions at the fluid--structure interface in rarefied gas
flow within slip regime. In this method, the compressible flow governed by
Navier-Stokes equations are solved by using high-order finite difference
method; the elastic solid is solved by using finite element method; the fluid
and solid are solved independently and the fluid--structure--thermal
interaction are achieved by using a penalty method in a partitioned way.
Several validations are conducted including Poiseuille flow in a 2D pipe, flow
around a 2D NACA airfoil, moving square cylinder in a 2D pipe, flow around a
sphere and moving sphere in quiescent flow. The numerical results from present
method show good agreement with the previous published data obtained by other
methods, and it confirms the the good ability of the proposed method in
handling fluid--structure--thermal interaction for both weakly compressible and
highly compressible rarefied gas flow. To overcome the incapability of
Navier-Stokes equations at high local Knudsen numbers in supersonic flow, an
artificial viscosity is introduced to ease the sharp transition at the shock
wave front. Inspired by Martian exploration, the application of proposed method
to study the aerodynamics of flapping wing in rarefied gas flow is conducted in
both 2D and 3D domains, to obtain some insights for the flapping-wing aerial
vehicles operating in Martian environment
- …