Joint face and head tracking inside multi-camera smart rooms

The paper introduces a novel detection and tracking system that provides both frame-view and world-coordinate human location information, based on video from multiple synchronized and calibrated cameras with overlapping fields of view. The system is developed and evaluated for the specific scenario of a seminar lecturer presenting in front of an audience inside a “smart room”, its aim being to track the lecturer’s head centroid in the three-dimensional (3D) space and also yield two-dimensional (2D) face information in the available camera views. The proposed approach is primarily based on a statistical appearance model of human faces by means of well-known AdaBoost-like face detectors, extended to address the head pose variation observed in the smart room scenario of interest. The appearance module is complemented by two novel components and assisted by a simple tracking drift detection mechanism. The first component of interest is the initialization module, which employs a spatio-temporal dynamic programming approach with appropriate penalty functions to obtain optimal 3D location hypotheses. The second is an adaptive subspace learning based 2D tracking scheme with a novel forgetting mechanism, introduced to reduce tracking drift and increase robustness. System performance is benchmarked on an extensive database of realistic human interaction in the lecture smart room scenario, collected as part of the European integrated project “CHIL”. The system consistently achieves excellent tracking precision, with a 3D mean tracking error of less than 16 cm, and is demonstrated to outperform four alternative tracking schemes. Furthermore, the proposed system performs relatively well in detecting frontal and near-frontal faces in the available frame views. This work was performed while Zhenqiu Zhang was on a summer internship with the Human Language Technology Department at the IBM T.J. Watson Research Center.     

Fast Firmware Implementation of RSA-Like Security Protocol for Mobile Devices

In modern mobile communications, personal privacy and security are of top concern to mobile phone subscribers. Yet, owing to the limit of their processing capability, mainstream mobile manufacturers are still unable to apply advanced security protocol to mobile devices. It should be noted that many security protocols are based on RSA algorithm. To implement RSA algorithm and thus apply many advanced security protocols to mobile networks, this paper proposes an efficient and practical method based on the Texas Instruments TMS320C55x family. When the proposed method is employed, it takes only 7.9 milliseconds to perform a 1024-bit RSA encryption operation at the clock frequency of 200 MHz. Our decryption operation is at least 3.5 times faster than the time taken to perform the same operation without employing the proposed method. In addition, the proposed method can stop any power-analysis attack on RSA-based security protocols, thereby enhancing the security of mobile environments.     

阵列误差影响下的RBF神经网络波达方向估计

针对阵列误差(阵元间互耦、通道失配)影响下波达方向估计问题,提出一种新型的基于径向基神经网络侦察测向系统。这种系统采用直接数据域补偿算法对输入数据进行误差补偿,从而获得正确的基函数中心。在无需对RBF神经网络测向系统作任何改进的情况下,可获得对波达方向的准确估计。为了减少输入,利用信号协方差矩阵的对称性以及对角线元素不包含信号方向信息的特点,仅考虑协方差矩阵中的上三角部分元素作为网络输入。给出了应用该方法的具体步骤。仿真实验表明,基于这种RBF网络的侦察测向系统达到了很高的精度。     

光探测器芯片小信号等效电路模型的建立

提出了一种光探测器芯片小信号等效电路模型及其建立方法,首先根据光探测器的物理结构确定其等效电路模型,模型考虑了影响光探测器高频性能的主要因素，然后精确测量了光探测器芯片的S参数,通过遗传算法对测量的S参数进行拟合,最终计算出模型的各个参量，在130MHz-20GHz范围内的实验结果表明,模型仿真结果与测量结果相吻合,证明了建模方法的可靠性。该模型有效地模拟了光探测器芯片的高频特性,利用该模型可以对光探测器及相应光电集成器件进行电路级仿真和优化。     

TD-SCDMA的HSUPA技术

TD-SCDMA的高速上行分组接入（HSUPA）作为3G增强技术,可以有效提高上行速率、增加吞吐量、减少延时。其加入的增强上行链路专用信道（E-DCH）和MAC层实体MAC-e/es保证了混合自动重传（HARQ）、NodeB调度以及高阶调制等这些关键技术的实现。     

激光感应复合熔覆界面特性研究

在送粉激光感应复合熔覆试验的基础上,研究了工艺参数对熔覆层与基体结合界面形态及组织结构的影响规律.研究结果表明,激光感应复合熔覆工艺参数对熔覆层与基体界面特性有显著影响.随扫描速度增加,界面形态由平直向波浪形变化;随送粉速率增加,结合界面的平直度增加;扫描速度和送粉速率对界面形态的影响随感应能量增加而减弱.感应作用促使结合界面由波浪起伏状向平直转变,且在界面处形成粗大的柱状树枝晶.     

Advances in the scalable amendment of H.264/AVC

To support clients with diverse capabilities, ISO/IEC MPEG and ITU-T form a joint video team (JVT) to develop a scalable video coding (SVC) technology that uses single bitstream to provide multiple spatial, temporal, and quality (SNR) resolutions, thus satisfying low-complexity and low-delay constraints. It is an amendment of the emerging standard H.264/AVC and it provides an H.264/AVC-compatible base layer and a fully scalable enhancement layer, which can be truncated and extracted on-the-fly to obtain a preferred spatio-temporal and quality resolution. An overview of the adopted key technologies in the SVC and a comparison in coding efficiency with H.264/AVC are presented     

A 9.1–10.7 GHz 10-W, 40-dB Gain Four-Stage PHEMT MMIC Power Amplifier

This letter presents a compact X-band high gain and high power four-stage AlGaAs/InGaAs/GaAs pseudomorphic high electron mobility transistor (PHEMT) monolithic microwave integrated circuit (MMIC) high power amplifier (PA). This amplifier is designed to fully match a 50-Omega input and output impedance. Based on 0.35-mum gate-length power PHEMT technology, this PA MMIC is fabricated on a 3-mil thick wafer. While operating under 8 V and 2700-mA dc bias condition, the characteristics of 40-dB small-signal gain, a 10-W continuous-wave saturation output power, and 33% power added efficiency at 9.7GHz can be achieved     

Radio resource management of heterogeneous services in mobile WiMAX systems [Radio Resource Management and Protocol Engineering for IEEE 802.16]

IEEE 802.16e, known as mobile WiMAX, has gained much attention recently for its capability to support high transmission rates in cellular environments and QoS for different applications. Beyond what the standard can define, in order to effectively support video streaming, VoIP, and data services, proprietary radio resource management, including multiconnection assignment, scheduling controls, and call admission controls, are essential. In this study we evaluate the downlink performance of a mobile WiMAX cellular system with different radio resource management, especially the scheduler for QoS control and the implementation of multiconnection for streaming applications     

A Fundamental 90-GHz CMOS VCO Using New Ring-Coupled Quad

A new circuit topology, named ring-coupled quad for millimeter-wave voltage controlled oscillator (VCO) design, is proposed. The proposed circuit topology provides higher open loop voltage gain than conventional cross-coupled pair. The layout of the proposed ring-coupled quad is fully symmetric without additional interconnection lines. A 90-GHz VCO using 90-nm CMOS process is implemented with this ring-coupled quad. This 90-GHz oscillator demonstrates a 2.5-GHz tuning range and higher than -20dBm output power. The proposed ring-coupled quad is suitable for the realization of high frequency VCOs