A local variance-controlled reversible data hiding method using prediction and histogram-shifting

The stego image quality produced by the histogram-shifting based reversible data hiding technique is high; however, it often suffers from lower embedding capacity compared to other types of reversible data hiding techniques. In 2009, Tsai et al. solved this problem by exploiting the similarity of neighboring pixels to construct a histogram of prediction errors; data embedding is done by shifting the error histogram. However, Tsai et al.’s method does not fully exploit the correlation of the neighboring pixels. In this paper, a set of basic pixels is employed to improve the prediction accuracy, thereby increasing the payload. To further improve the image quality, a threshold is used to select only low-variance blocks to join the embedding process. According to the experimental results, the proposed method provides a better or comparable stego image quality than Tsai et al.’s method and other existing reversible data hiding methods under the same payload.     

A Data‐driven Segmentation for the Shoulder Complex

The human shoulder complex is perhaps the most complicated joint in the human body being comprised of a set of three bones, muscles, tendons, and ligaments. Despite this anatomical complexity, computer graphics models for motion capture most often represent this joint as a simple ball and socket. In this paper, we present a method to determine a shoulder skeletal model that, when combined with standard skinning algorithms, generates a more visually pleasing animation that is a closer approximation to the actual skin deformations of the human body. We use a data‐driven approach and collect ground truth skin deformation data with an optical motion capture system with a large number of markers (200 markers on the shoulder complex alone). We cluster these markers during movement sequences and discover that adding one extra joint around the shoulder improves the resulting animation qualitatively and quantitatively yielding a marker set of approximately 70 markers for the complete skeleton. We demonstrate the effectiveness of our skeletal model by comparing it with ground truth data as well as with recorded video. We show its practicality by integrating it with the conventional rendering/animation pipeline.     

A Linear-Time Algorithm for Symmetric Convex Drawings of Internally Triconnected Plane Graphs

We study a crossing minimization problem of drawing a bipartite graph with a radial drawing of two orbits. Radial drawings are one of well-known drawing conventions in social network analysis and visualization, in particular, displaying centrality indices of actors (Wasserman and Faust, Social Network Analysis: Methods and Applications. Cambridge University Press, Cambridge, 1994). The main problem in this paper is called the one-sided radial crossing minimization, if the positions of vertices in the outer orbit are fixed. The problem is known to be NP-hard (Bachmaier, IEEE Trans. Vis. Comput. Graph. 13, 583–594, 2007), and a number of heuristics are available (Bachmaier, IEEE Trans. Vis. Comput. Graph. 13, 583–594, 2007). However, there is no approximation algorithm for the crossing minimization problem in radial drawings. We present the first polynomial time constant-factor approximation algorithm for the one-sided radial crossing minimization problem.     

面向小型全自动生化分析仪的同步可靠的UART通信

为了在小型全自动生化分析控制系统中实现双单片机之间同步、可靠的数据传输,提出了一种基于握手等待协议的同步可靠的UART通信系统方案。采用3次等待握手协议实现通信的同步,在数据传输过程中加入同步数据改进传输应用的稳定性。目前该方案已成功应用于小型全自动生化分析仪控制系统的数据传输,运行情况良好,性能稳定可靠。     

基于FPGA的1553B通信模块的设计

提出一种将FPGA与PowerPC芯片结合,实现MIL-STD-1553B通信模块的技术方案。详细讨论了该系统的结构、1553B总线协议在FPGA上的实现以及系统的软件结构等关键技术。该系统方案与采用专用的协议芯片实现1553总线接口的方法相比,具有更灵活、成本更低、可移植性好等特点。     

SVC在无线信道传输中的非均衡差错保护

针对H.264的可伸缩视频编码扩展标准(SVC)在噪声信道中的传输,采用低密度奇偶校验码(LDPC)提出一种非均衡差错保护的方案。在所提的方案中,根据时间、分辨率和质量把原视频序列按重要性分成不同的层。由于不同层的数据对错误的敏感性不同,对其进行不同码率的LDPC信道编码,实现非均衡差错保护。根据视频流中每一帧不同层的PSNR增量不同,和不同信道码率下正确解码的概率不同,反复计算每一帧所有码率组合的PSNR增量值并找出最大组,从而进行信道编码并传输。实验表明,在相同的平均码率条件下,提出的方案相比其他方案的PSNR值增加了2.8 dB,更适合无线信道的传输。     

基于C8051F120和CPLD的多功能望远镜控制系统设计

基于C8051F120和大规模CPLD(EPM570T144)设计的多功能望远镜大型转台两轴控制系统,包括两轴直流电机伺服控制器、GPS时统系统、增量式编码器采样读数、PWM功能模块、LCD显示功能、通信功能、AD采样功能等。功能齐全,结构紧凑,外部接口丰富且具有保护功能,可靠性高。     

基于DSP和FPGA的经纬仪控制系统设计

DSP和FPGA组成的伺服控制系统能够满足复杂的控制算法要求。通过对TI公司的DSP控制芯片TMS320F2812和ALTERA公司的FPGA芯片EP1C3T144的功能和特点分析,给出了一种基于DSP和FPGA的光电经纬仪伺服控制电路的设计方案。增加了可靠性和精度。     

基于智能天线的多用户MIMO-OFDM联合发送技术研究

提出了一种基于智能天线(SA)的多用户MIMO-OFDM联合发送(JT)方案,给出了系统模型,推导出了权向量和数据发送及检测算法。通过在TD-SCDMA系统应用环境中的仿真和分析,表明基于SA的多用户MIMO-OFDM的JT技术具有比基于多用户MIMO的JT技术更优良的误比特率性能。     

Modeling, microfabrication and experiments of a free–free cantilever bistable micro mechanism supported with a diamond configuration

Bistable micro mechanisms are gaining great attention in MEMS applications. This paper presents the mechanical modeling and experimental characterization of a bistable torsion/cantilever micro latching mechanism for performing low power bistable relay applications. The bistable micro mechanism consists of two cantilevers which form symmetrical rocker levers. The free–free cantilever is suspended by a diamond skeleton which in turn is attached to a torsion cantilever. A permanent magnet is placed beside for holding the closed state with a permalloy soft magnetic circuit. The special diamond support is designed to enhance the stiffness of the overhang beams. In order to deduce the spring stiffness of system, a mechanical modeling of the leveraged torsion/cantilever system was performed by Castigliano’s theorem. Meanwhile, the magnetostatic latching force was also deduced by the Maxwell electromagnetism theory. Then the device has been prepared by a laminated copper sacrificial layer process. This process can facilitate the fabrication complexities of traditional magnetic device with coil structures. Finally, mechanical performance was characterized by an atomic force microscopy, combined with finite element simulation using ANSYS^™ package and analysis model as well. Two stable states of the micro mechanism were hold successfully with no power consumption by interferoscope profilometry of WYKO optical profiling system.