多标准视频编码器下的运动估计评估

运动估计是视频编码过程中最为复杂和耗时的阶段。为分析和优化其性能,从多个流行的开源视频编码器中提取出单独的运动估计算法模块,根据视频分辨率和视频内容的不同建立程序输入集,从而构成一套完整的测试程序集合。利用性能分析工具对算法性能和微体系结构性能进行量化分析,给出这些算法在当今主流处理器体系结构上的性能差异。实验结果表明,复杂视频和高分辨率视频下的运动估计算法耗时最长,且大部分算法的指令级并行性没有太大差异。算法最后一级高速缓存的缺失率和分支误预测率都较低,分别在0.01%和7%以下。     

A Low-Power Multithreaded Processor for Software Defined Radio

Embedded digital signal processors for software defined radio have stringent design constraints including high computational bandwidth, low power consumption, and low interrupt latency. Furthermore, due to rapidly evolving communication standards with increasing code complexity, these processors must be compiler-friendly, so that code for them can quickly be developed in a high-level language. In this paper, we present the design of the Sandblaster Processor, a low-power multithreaded digital signal processor for software defined radio. The processor uses a unique combination of token triggered threading, powerful compound instructions, and SIMD vector operations to provide real-time baseband processing capabilities with very low power consumption. We describe the processor’s architecture and microarchitecture, along with various techniques for achieving high performance and low power dissipation. We also describe the processor’s programming environment and the SB3010 platform, a complete system-on-chip solution for software defined radio. Using a super-computer class vectorizing compiler, the SB3010 achieves real-time performance in software on a variety of communication protocols including 802.11b, GPS, AM/FM radio, Bluetooth, GPRS, and WCDMA. In addition to providing a programmable platform for SDR, the processor also provides efficient support for a wide variety of digital signal processing and multimedia applications. Michael Schulte received a B.S. degree in Electrical Engineering from the University of Wisconsin-Madison in 1991, and M.S. and Ph.D. degrees in Electrical Engineering from the University of Texas at Austin in 1992 and 1996, respectively. From 1996 to 2002, he was an assistant and associate professor at Lehigh University, where he directed the Computer Architecture and Arithmetic Research Laboratory. He is currently an assistant professor at the University of Wisconsin-Madison, where he leads the Madison Embedded Systems and Architectures Group. His research interests include high-performance embedded processors, computer architecture, domain-specific systems, computer arithmetic, and wireless systems. He is a senior member of the IEEE and the IEEE Computer Society, and an associate editor for the IEEE Transactions on Computers and the Journal of VLSI Signal Processing. John Glossner is CTO & Executive Vice President at Sandbridge Technologies. Prior to co-founding Sandbridge, John managed the Advanced DSP Technology group, Broadband Transmission Systems group, and was Access Aggregation Business Development manager at IBM’s T.J. Watson Research Center. Prior to IBM, John managed the software effort in Lucent/Motorola’s Starcore DSP design center. John received a Ph.D. in Computer Architecture from TU Delft in the Netherlands for his work on a Multithreaded Java processor with DSP capability. He also received an M.S. degree in Engineering Management and an M.S.E.E. from NTU. John also holds a B.S.E.E. degree from Penn State. John has more than 60 publications and 12 issued patents. Dr. Sanjay Jinturkar is the Director of Software at Sandbridge and manages the systems software and communications software groups. Previously, he managed the software tools group at StarCore. He has a Ph.D in Computer Science from University of Virginia and holds 20 publications and 4 patents. Mayan Moudgill obtained a Ph.D. in Computer Science from Cornell University in 1994, after which he joined IBM at the Thomas J. Watson Research Center. He worked on a variety of computer architecture and compiler related projects, including the VLIW research compiler, Linux ports for the 40x series embedded processors and simulators for the Power 4. In 2001, he co-founded Sandbridge Technologies, a start-up that is developing digital signal processors targeted at 3G wireless phones. Suman Mamidi is a graduate student in the Department of Electrical and Computer Engineering at the University of Wisconsin-Madison. He received his M.S. degree from the University of Wisconsin-Madison in December, 2003 and is currently working towards his PhD. His research interests include low-power processors, hardware accelerators, multithreaded processors, reconfigurable hardware, and embedded systems. Stamatis Vassiliadis was born in Manolates, Samos, Greece, in 1951. He is currently a Chair Professor in the Electrical Engineering, Mathematics, and Computer Science (EEMCS) department of Delft University of Technology (TU Delft), The Netherlands. He previously served in the Electrical and Computer Engineering faculties of Cornell University, Ithaca, NY and the State University of New York (S.U.N.Y.), Binghamton, NY. For a decade, he worked with IBM, where he was involved in a number of advanced research and development projects. He received numerous awards for his work, including 24 publication awards, 15 invention awards, and an outstanding innovation award for engineering/scientific hardware design. His 73 USA patents rank him as the top all time IBM inventor. Dr. Vassiliadis is an ACM fellow, an IEEE fellow and a member of the Royal Netherlands Academy of Arts and Sciences (KNAW).     

Accuracy of 3D MR microscopy for trabecular bone assessment: a comparative study on calcaneus samples using 3D synchrotron radiation microtomography

Magnetic resonance (MR) imaging is attractive for a noninvasive and radiation-free assessment of in vivo trabecular bone architecture. However the quantitative evaluation of architectural parameters could be biased by the limited sensitivity of MR. The aim of this study was to determine the accuracy of trabecular bone architectural parameters obtained from 3D high-resolution MR images, by comparison to reference images obtained by high-resolution X-ray microtomography using synchrotron radiation, from 29 samples of human calcaneus. MR images were obtained with a 66 m×66 m×66 m voxel size, using a 8.5 T MR microscope. Microtomography images were acquired with a 10 m×10 m×10 m voxel size, from the same samples. 3D architectural parameters characterizing the morphometry, topology, anisotropy, and orientation were computed from both modalities and carefully compared. To avoid errors, an identical region of interest was selected in the two corresponding images, and the same algorithms were run at identical spatial resolution. Our results establish that network connectivity, orientation and anisotropy are reliable from the MR data. The bone volume fraction, and morphometric parameters measured from the MR data, were found to be biased with respect to their values from the microtomography data, although there was a significant correlation between the two modalities.An erratum to this article can be found at     

Survey of MRI Usefulness for the Clinical Assessment of Bone Microstructure

Bone microarchitecture has been shown to provide useful information regarding the evaluation of skeleton quality with an added value to areal bone mineral density, which can be used for the diagnosis of several bone diseases. Bone mineral density estimated from dual-energy X-ray absorptiometry (DXA) has shown to be a limited tool to identify patients’ risk stratification and therapy delivery. Magnetic resonance imaging (MRI) has been proposed as another technique to assess bone quality and fracture risk by evaluating the bone structure and microarchitecture. To date, MRI is the only completely non-invasive and non-ionizing imaging modality that can assess both cortical and trabecular bone in vivo. In this review article, we reported a survey regarding the clinically relevant information MRI could provide for the assessment of the inner trabecular morphology of different bone segments. The last section will be devoted to the upcoming MRI applications (MR spectroscopy and chemical shift encoding MRI, solid state MRI and quantitative susceptibility mapping), which could provide additional biomarkers for the assessment of bone microarchitecture.     

Yak (Bos grunniens) milk improves bone mass and microarchitecture in mice with osteoporosis

The effect of milk on bone health is controversial. In this study, the effects of yak milk in mice with retinoic acid-induced osteoporosis (OP) were evaluated. Yak milk was provided to OP mice as a nutrition supplement for 6 wk. The results showed that yak milk significantly reduced bone turnover markers (tartrate acid phosphatase and alkaline phosphatase). The yak milk treatment was also associated with remarkably increased bone mineral density, bone volume, trabecular thickness, and trabecular number, as well as improved biomechanical properties (maximum load and stress) of the tibia. Furthermore, yak milk mitigated the deterioration of the network and thickness of trabecular bone in treated OP mice compared with the OP model group. The results indicated that yak milk could improve bone mass and microarchitecture through the inhibition of bone resorption in OP mice.     

Solanum muricatum Ameliorates the Symptoms of Osteogenesis Imperfecta In Vivo

Pepino (Solanum muricatum), which is an evergreen plant native to South America, is well‐known for its effects in antioxidation, antidiabetic activity, anti‐inflammation, and antitumor activity. A previous study in our lab indicated that Solanum muricatum (SM) extract promoted osteogenic differentiation by upregulating Wnt and BMP signaling pathway in rat bone marrow stromal cells. The osteogenesis imperfecta (OI) mouse model was used in order to further discover the osteogenic properties of SM extract in the present research. We utilized microCT analysis to collect bone mass and microarchitectural parameters at vertebrae and at femur metaphysis in OI mice. Raman spectrometry was applied to identify change of bone mineral and matrix composition during SM treatment. Finally, collagen synthesis marker PINP and collagen degradation marker CTX were detected using enzyme immunoassay. SM extract could improve the bone mass and microarchitectural parameters both at vertebrae and at femur metaphysis. It also significantly increased the collagen content by promoting its biosynthesis and inhibiting its degradation. By using heterozygous Col1a1^Jrt/+ mice as a model of OI, 6 weeks treatment of SM extract could significantly ameliorate the symptoms in OI mice. Thus, SM holds potential for developing new drugs of bone formation and bone remodeling.     

Pentium4处理器微体系结构分析

描述了Intel Pentium4的NetBurst微体系结构，着重分析其内部实现的细节，回顾了Intel处理器的设计，分析了NetBurst微体系结构，再结合其内部功能单元，分析了其指令流水的过程，最后，给出了Pentium4的性能评测。     

一种电机FOC算法DSP系统设计及实现

本文设计了一种适用于电机矢量控制算法的数字信号处理系统的微架构定义,包括其指令集定义、存储器模型以及与主CPU的交互模式.该设计具有通过固定部分多操作数有效缩减指令编码长度提高代码密度以及后台执行多周期指令提高ALU并行效率的显著优点.文中给出了典型的FOC控制算法在DSP （Digital Signal Processor）指令集上实现的指令周期数,也给出了对应架构的电路实现情况,最终以ARM CORTEX-M0及几款主流DSP作为比较基线,通过实测实验数据证明了体系结构的高能效比,以较为有限的电路面积代价,极大提高了集成DSP的嵌入式系统的运行效率.     

Self-assembled 3D flower-like NaY(MoO4)2:Eu microarchitectures: Hydrothermal synthesis, formation mechanism and luminescence properties

Self-assembled 3D flower-like NaY(MoO₄)₂:Eu³⁺ microarchitectures were successfully synthesized by a glycine-assisted hydrothermal method at 180 °C. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and high resolution transmission electron microscopy (HRTEM) were employed to characterize the as-obtained products. It was found that morphology modulation could be easily realized by changing the time of hydrothermal reaction system. 3D flower-like NaY(MoO₄)₂:Eu³⁺ microarchitectures were formed with 72 h reaction time. The formation mechanism for flower-like architecture was proposed on the basis of a series of time-dependent experiments. The NaY(MoO₄)₂:Eu³⁺ powders obtained can be effectively excited by 396 nm light, and exhibit strong red emission around 615 nm, attributed to the Eu³⁺⁵D₀ → ⁷F₂ transition. An investigation on the photoluminescence (PL) properties of NaY(MoO₄)₂:Eu³⁺ obtained revealed that the luminescence properties were correlated with the morphology and size.     

A Buffer-Oriented Methodology for Microarchitecture Validation

We propose a methodology for validating microarchitecture specifications. We view microarchitecture features as specific operations on entries of various buffers in the processor. Our validation approach is to determine the functionality of a buffer type, model its operations at the microarchitecture level using abstract finite state machine (FSM) models, and rigorously generate instruction sequences that systematically exercise the model of each instance of that buffer type. A high-level test sequence is derived based on the abstract FSM model using FSM testing techniques, and then translated to a test program that exercises the functionality of each buffer entry. This methodology is applied to the microarchitecture specifications of the PowerPC 604. The effectiveness of the sequences generated using our methodology is compared with that of some real and randomly-generated programs. Simulation results show that all targeted FSM transitions are covered by our sequences with at least 1000 × and 3 × fewer instructions than real and randomly-generated programs, respectively.