Feature extraction using recursive cluster-based linear discriminant with application to face recognition.

A novel recursive procedure for extracting discriminant features, termed recursive cluster-based linear discriminant (RCLD), is proposed in this paper. Compared to the traditional Fisher linear discriminant (FLD) and its variations, RCLD has a number of advantages. First of all, it relaxes the constraint on the total number of features that can be extracted. Second, it fully exploits all information available for discrimination. In addition, RCLD is able to cope with multimodal distributions, which overcomes an inherent problem of conventional FLDs, which assumes uni-modal class distributions. Extensive experiments have been carried out on various types of face recognition problems for Yale, Olivetti Research Laboratory, and JAFFE databases to evaluate and compare the performance of the proposed algorithm with other feature extraction methods. The resulting improvement of performances by the new feature extraction scheme is significant.     

Automatic quantification of changes in bone in serial MR images of joints

Recent innovations in drug therapies have made it highly desirable to obtain sensitive biomarkers of disease progression that can be used to quantify the performance of candidate disease modifying drugs. In order to measure potential image-based biomarkers of disease progression in an experimental model of rheumatoid arthritis (RA), we present two different methods to automatically quantify changes in a bone in in-vivo serial magnetic resonance (MR) images from the model. Both methods are based on rigid and nonrigid image registration to perform the analysis. The first method uses segmentation propagation to delineate a bone from the serial MR images giving a global measure of temporal changes in bone volume. The second method uses rigid body registration to determine intensity change within a bone, and then maps these into a reference coordinate system using nonrigid registration. This gives a local measure of temporal changes in bone lesion volume. We detected significant temporal changes in local bone lesion volume in five out of eight identified candidate bone lesion regions, and significant difference in local bone lesion volume between male and female subjects in three out of eight candidate bone lesion regions. But the global bone volume was found to be fluctuating over time. Finally, we compare our findings with histology of the subjects and the manual segmentation of bone lesions.     

Low‐Threshold Distributed‐Feedback Lasers Based on Pyrene‐Cored Starburst Molecules with 1,3,6,8‐Attached Oligo(9,9‐Dialkylfluorene) Arms

Here, a detailed characterization of the optical gain properties of sky‐blue‐light‐emitting pyrene‐cored 9,9‐dialkylfluorene starbursts is reported; it is shown that these materials possess encouragingly low laser thresholds and relatively high thermal and environmental stability. The materials exhibit high solid‐state photoluminescence (PL) quantum efficiencies (>90%) and near‐single‐exponential PL decay transients with excited state lifetimes of ～1.4 ns. The thin‐film slab waveguide amplified spontaneous emission (ASE)‐measured net gain reaches 75–78 cm^?1. The ASE threshold energy is found to remain unaffected by heating at temperatures up to 130 °C, 40 to 50 °C above T_g. The ASE remained observable for annealing temperatures up to 170 or 200 °C. 1D distributed feedback lasers with 75% fill factor and 320 nm period show optical pumping thresholds down to 38–65 Wcm^?2, laser slope efficiencies up to 3.9%, and wavelength tuning ranges of ～40 nm around 471–512 nm. In addition, these lasers have relatively long operational lifetimes, with N_1/2 ≥ 1.1 × 10⁵ pulses for unencapsulated devices operated at ten times threshold in air.     

Achievable sum‐rate analysis of correlated two‐antenna MIMO uplink channels

This paper analyzes the achievable sum‐rate of correlated two‐antenna multiple‐input multiple‐output (MIMO) uplink channels. Most of previous works have considered the case when a single user has multiple transmit antennas (i.e. multi‐antenna single‐user scenario). This paper considers the case when two‐antenna MIMO uplink channels comprise two users with a single transmit antenna (i.e. single‐antenna two‐user scenario). The analytic and simulation results show that the achievable sum‐rate of correlated single‐antenna two‐user MIMO uplink channels highly depends on the angle difference between the receive correlation coefficients of two users. It is also shown that the achievable sum‐rate of correlated single‐antenna two‐user MIMO uplink channels is larger than that of correlated two‐antenna single‐user MIMO uplink channels and can even be larger than that of independent and identically distributed Rayleigh two‐antenna MIMO uplink channels. Copyright © 2009 John Wiley & Sons, Ltd.     

A highly efficient OLED based on terbium complexes

A neutral ligand 9-(4-tert-butylphenyl)-3,6-bis(diphenylphosphineoxide)-carbazole (DPPOC) and its complex Tb(PMIP)₃DPPOC (A, where PMIP stands for 1-phenyl-3-methyl-4-isobutyryl-5-pyrazolone) were synthesized. DPPOC has a suitable lowest triplet energy level (24,691 cm^?1) for the sensitization of Tb(III) (⁵D₄: 20,400 cm^?1) and a significantly higher thermal stability (glass transition temperature 137 °C) compared with the familiar ligand triphenylphosphine oxide (TPPO). Experiments revealed that the emission layer of the Tb(PMIP)₃DPPOC film could be prepared by vacuum co-deposition of the complex Tb(PMIP)₃(H₂O)₂ (B) and DPPOC (molar ratio = 1:1). The electroluminescent (EL) device ITO/N,N′-diphenyl-N,N′-bis(1-naphthyl)-1,1′-diphenyl-4,4′-diamine (NPB; 10 nm)/Tb(PMIP)₃ (20 nm)/co-deposited Tb(PMIP)₃DPPOC (30 nm)/2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP; 10 nm)/tris(8-hydroxyquinoline) (AlQ; 20 nm)/Mg_0.9Ag_0.1 (200 nm)/Ag (80 nm) exhibited pure emission from terbium ions, even at the highest current density. The highest efficiency obtained was 16.1 lm W^?1, 36.0 cd A^?1 at 6 V. At a practical brightness of 119 cd m^?2 (11 V) the efficiency remained above 4.5 lm W^?1, 15.7 cd A^?1. These values are a significant improvement over the previously reported Tb(PMIP)₃(TPPO)₂ (C).     

硼原子对Si(100)衬底上Ge量子点生长的影响

研究了硼原子对 Si( 1 0 0 )衬底上 Ge量子点自组织生长的影响 .硼原子的数量由 0单原子层变到 0 .3单原子层 .原子力显微镜的观察表明 ,硼原子不仅对量子点的大小 ,而且对其尺寸均匀性及密度都有很大影响 .当硼原子的数量为 0 .2单原子层时 ,获得了底部直径为 60± 5nm,面密度为 6× 1 0 9cm- 2 ,且均匀性很好的 Ge量子点 .另外 ,还简单讨论了硼原子对 Ge量子点自组织生长影响的机制 .     

本地WDM网络节点上波分复用设备的配置

本文对本地WDM网络节点上波分复用设备的配置进行了分析 ,认为在城域WDM网中一般只配前置放大器 ,而大本地网需在收端配前置放大器 ,发端配功率放大器 ,对于节点距离超过100km的情况下 ,需加线路放大器     

一种GSM基站电源及环境集中监控系统的实现

介绍了一种GSM基站电源及环境集中监控系统的技术实现方法.     

基于多项式分解的自适应FIR滤波器脉动结构

该文由多项式信号的并行表达得到一种FIR滤波器并行结构。通过对FIR滤波器并行结构的分析,提出了几种自适应FIR滤波器的并行处理算法．同时给出了相应的脉动实现结构。     

电信BS架构系统迁移及云化研究

深入分析了电信BS架构系统迁移的相关问题及解决方案,并对BS架构系统IaaS及PaaS云化方案进行了研究,提出了两种IaaS和一种PaaS解决方案,能有效地解决电信BS架构系统Web及应用层云化相关问题,同时给出了迁移及云化演进路径和分阶段推进建议,对于推进云计算在IT支撑系统中的应用,具有较好的价值贡献。