抗故障攻击的专用芯片存储单元设计

在复用检测和线性校验码检测的基础上,提出互补存储、奇偶校验和汉明码校验三种存储单元的抗故障攻击防护方案。应用这三种方案,用硬件描述语言Verilog设计了三种抗故障攻击双端口RAM存储器,在Altera公司的器件EP1C12Q240C8上予以实现。通过仿真验证,三种带故障检测的RAM具有较高的故障检测概率,而对硬件芯片性能影响不大。     

Evaluation of the DART 3D model in the thermal domain using satellite/airborne imagery and ground-based measurements

This work provides an evaluation of the discrete anisotropy radiative transfer (DART) three-dimensional (3D) model in assessing the simulation of directional brightness temperatures (T _b) at both sensor and surface levels. Satellite imagery acquired with the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), airborne imagery acquired with the Airborne Hyperspectral Scanner (AHS) sensor and ground-based measurements collected over an agricultural area were used to evaluate the DART model at nadir views. Directional radiometric temperatures measured with a goniometric system at ground level were also used to evaluate modelling results at different view angles. The DART model was evaluated over three homogeneous plots: bare soil (BS), green grass (GG) and sand (NS). The results show good agreement between the simulations and the satellite, airborne and ground-based measurements, with root mean square errors (RMSEs) less than 2.0 K. However, three major discrepancies were found: (1) differences greater than 4.0 K over BS when comparing DART and ASTER, attributed to turbulence-induced temperature fluctuations, (2) higher differences in sensor-level than in surface-level comparisons when using AHS due to thermal heterogeneity of the selected regions of interest in the image and also to differences in atmospheric correction performed over the imagery and the correction included in the DART model, especially for bands located in the lowest atmospheric transmissivity regions and (3) RMSEs greater than 2.0 K when comparing DART results and ground measurements over the NS plot, due to the strong emissivity correction in the 8.0–9.0 μm bands, where the measured emissivity was below 0.75. Despite these discrepancies, we show that the DART model is a useful tool for simulating remotely sensed thermal images over different landscapes. Finally, new versions of this model are continuously being released to solve technical problems and improve the simulation results.     

一种有效的EEPLA的测试算法

本文提出了一种硬件电路很少,故障覆盖率最高的ＥＥＰＬＡ的测试算法。同其他测试算法相比,该方法可以对每一个交叉点进行编程控制。所有单一的或多重的交叉点故障、线电位固定在“１”（“０”）、桥连故障都可以测试到,疽测试算法简单易行。     

Influence of woody elements of a Norway spruce canopy on nadir reflectance simulated by the DART model at very high spatial resolution

A detailed sensitivity analysis investigating the effect of woody elements introduced into the Discrete Anisotropic Radiative Transfer (DART) model on the nadir bidirectional reflectance factor (BRF) for a simulated Norway spruce canopy was performed at a very high spatial resolution (modelling resolution 0.2 m, output pixel size 0.4 m). We used such a high resolution to be able to parameterize DART in an appropriate way and subsequently to gain detailed understanding of the influence of woody elements contributing to the radiative transfer within heterogeneous canopies. Three scenarios were studied by modelling the Norway spruce canopy as being composed of i) leaves, ii) leaves, trunks and first order branches, and finally iii) leaves, trunks, first order branches and small woody twigs simulated using mixed cells (i.e. cells approximated as composition of leaves and/or twigs turbid medium, and large woody constituents). The simulation of each scenario was performed for 10 different canopy closures (CC = 50-95%, in steps of 5%), 25 leaf area index (LAI = 3.0-15.0 m² m^− 2, in steps of 0.5 m² m^− 2), and in four spectral bands (centred at 559, 671, 727, and 783 nm, with a FWHM of 10 nm). The influence of woody elements was evaluated separately for both, sunlit and shaded parts of the simulated forest canopy, respectively. The DART results were verified by quantifying the simulated nadir BRF of each scenario with measured Airborne Imaging Spectroradiometer (AISA) Eagle data (pixel size of 0.4 m). These imaging spectrometer data were acquired over the same Norway spruce stand that was used to parameterise the DART model.The Norway spruce canopy modelled using the DART model consisted of foliage as well as foliage including robust woody constituents (i.e. trunks and branches). All results showed similar nadir BRF for the simulated wavelengths. The incorporation of small woody parts in DART caused the canopy reflectance to decrease about 4% in the near-infrared (NIR), 2% in the red edge (RE) and less than 1% in the green band. The canopy BRF of the red band increased by about 2%. Subsequently, the sensitivity on accounting for woody elements for two spectral vegetation indices, the normalized difference vegetation index (NDVI) and the angular vegetation index (AVI), was evaluated. Finally, we conclude on the importance of including woody elements in radiative transfer based approaches and discuss the applicability of the vegetation indices as well as the physically based inversion approaches to retrieve the forest canopy LAI at very high spatial resolution.     

Designing fault-tolerant techniques for SRAM-based FPGAs

FPGAs have become prevalent in critical applications in which transient faults can seriously affect the circuit's operation. We present a fault tolerance technique for transient and permanent faults in SRAM-based FPGAs. This technique combines duplication with comparison (DWC) and concurrent error detection (CEO) to provide a highly reliable circuit while maintaining hardware, pin, and power overheads far lower than with classic triple-modular-redundancy techniques.     

DART: a 3D model for simulating satellite images and studying surface radiation budget

DART (Discrete Anisotropic Radiative Transfer) is a radiative transfer model that simulates remotely acquired images. It was originally developed to work in the short wavelengths (0.3–3?µm) within 3D natural scenes that are represented as matrices of rectangular cells containing trees, shrubs, grass, soil, etc. DART was recently modified to extend its domain of application and to improve its accuracy. This paper summarizes the major features of DART and presents the changes that were implemented for improving its accuracy. Presently, this model works with natural and urban landscapes, on the whole optical domain (thermal infrared included) and with a multispectral approach that uses optical data bases from 0.3?µm up to 15?µm. It simulates radiative transfer in the whole ‘atmosphere–Earth’ system and it accounts for the instrumental transfer function. Three major changes allowed us to improve DART accuracy by a factor of three: more accurate simulation of single and multiple scattering, use of a scheme that oversamples DART cells and a better account of the direction of radiation that gives rise to multiple scattered radiation.     

DART+: Direction-aware bichromatic reverse k nearest neighbor query processing in spatial databases

This article presents a novel type of queries in spatial databases, called the direction-aware bichromatic reverse k nearest neighbor(DBRkNN) queries, which extend the bichromatic reverse nearest neighbor queries. Given two disjoint sets, P and S, of spatial objects, and a query object q in S, the DBRkNN query returns a subset P′ of P such that k nearest neighbors of each object in P′ include q and each object in P′ has a direction toward q within a pre-defined distance. We formally define the DBRkNN query, and then propose an efficient algorithm, called DART, for processing the DBRkNN query. Our method utilizes a grid-based index to cluster the spatial objects, and the B⁺-tree to index the direction angle. We adopt a filter-refinement framework that is widely used in many algorithms for reverse nearest neighbor queries. In the filtering step, DART eliminates all the objects that are away from the query object more than a pre-defined distance, or have an invalid direction angle. In the refinement step, remaining objects are verified whether the query object is actually one of the k nearest neighbors of them. As a major extension of DART, we also present an improved algorithm, called DART+, for DBRkNN queries. From extensive experiments with several datasets, we show that DART outperforms an R-tree-based naive algorithm in both indexing time and query processing time. In addition, our extension algorithm, DART+, also shows significantly better performance than DART.     

Enabling high‐speed asynchronous data extraction and transfer using DART

As the complexity and scale of applications grow, managing and transporting the large amounts of data they generate are quickly becoming a significant challenge. Moreover, the interactive and real‐time nature of emerging applications, as well as their increasing runtime, make online data extraction and analysis a key requirement in addition to traditional data I/O and archiving. To be effective, online data extraction and transfer should impose minimal additional synchronization requirements, should have minimal impact on the computational performance and communication latencies, maintain overall quality of service, and ensure that no data is lost. In this paper we present Decoupled and Asynchronous Remote Transfers (DART), an efficient data transfer substrate that effectively addresses these requirements. DART is a thin software layer built on RDMA technology to enable fast, low‐overhead, and asynchronous access to data from a running simulation, and supports high‐throughput, low‐latency data transfers. DART has been integrated with applications simulating fusion plasma in a Tokamak, being developed at the Center for Plasma Edge Simulation (CPES), a DoE Office of Fusion Energy Science (OFES) Fusion Simulation Project (FSP). A performance evaluation using the Gyrokinetic Toroidal Code and XGC‐1 particle‐in‐cell‐based FSP simulations running on the Cray XT3/XT4 system at Oak Ridge National Laboratory demonstrates how DART can effectively and efficiently offload simulation data to local service and remote analysis nodes, with minimal overheads on the simulation itself. Copyright © 2010 John Wiley & Sons, Ltd.     

Protected query coding in multi-agent optoelectronic system

The intellectual agent scheme is proposed for protected coding in a multi-agent system. The interrelation is discussed of the agent architecture, query language and the multiple-valued logic protected coding method. Microcontroller units are proposed for hardware realizations of basic modules.     

User-like executives

A complex executive may be written as a core of minimum size, plus processes indistinguishable from those run by normal system users except for heavily circumscribed special privileges. Such an executive defines its virtual machine in a recursive fashion, since the processes abide by rules they help to enforce, and is ‘user-like’ because most executive processing takes places in the protected, user mode. The advantages of such an executive are compactness because of lack of duplication of user and executive routines, good documentation because the user-process interface is well defined and stable and, most important, excellent protection of the system from the executive itself, which utilizes all of the hardware protection available whenever possible. Situations most appropriate for the user-like technique are described, and a series of detailed examples is given to show its application to a multiprogramming executive's memory allocation service.     

FIR数字滤波器设计及其FPGA实现

以FPGA为硬件平台,利用FPGA的DSP开发工具DSP Builder对数字滤波器进行建模设计及系统模型仿真,生成VHDL工程文件,编制相应顶层文件,使其符合滤波器硬件系统。利用QuartusⅡ对项目进行综合、编译和调试,生成原理图模块和RTL电路图。通过对5 kHz方波信号进行仿真滤波,并将VHDL下载到硬件系统中进行硬件实现,有效地提取到5 kHz的正弦信号。实验结果表明,该设计很好地达到了FIR滤波器的性能,为数字滤波器的设计与实现提供了新的途径和方法。     

一种改进的GUI测试框架DART

针对当前的图形用户界面自动化测试中存在的局限性,提出一种每日自动回归测试（DART）框架的改进方案。研究DART流程、事件流图,包含了事件关联图的方法,实现对事件流图的优化,并采用权重选择法对DART方法进行改进,使之成为一种高效、简洁的自动冒烟测试框架。     

基于单片机控制红外线遥控的编码实现

介绍一种用MCS51单片机和红外遥控技术实现近距离无线通信的软硬件系统。为了使受控设备识别信号，设计一种数字信号编码系统，利用红外线将数字信号调制，而数据的解码则通过单片机完成。系统的抗干扰性能好，实现简单。     

一种时序型总线硬件木马的植入与检测

RS总线集成电路在航空航天及工业控制领域具有广泛的应用,随着集成电路硬件木马的检测成为研究热点,作为总线硬件木马研究领域的分支,其设计越来越受关注。在常规时序型硬件木马的基础上,针对RS232总线集成电路,设计一种基于可逆计数器的时序型总线硬件木马。采用Xillix公司的ISE软件在RTL层设计相应的RS232总线Verilog代码,并在常规和可逆时序型硬件木马触发阈值呈等差递增的条件下进行Modelsim仿真分析,结果表明,在总线功能需求复杂和传输数据较多的情况下,可逆时序型木马比常规时序型硬件木马具有灵活性和较低的触发率,隐蔽性更强。     

基于静态指令翻译技术的保护测试单元

现代微处理器中最为重要的一种工作模式为保护模式。对于复杂的保护模式,如果用硬件状态机实现需要花费较大的硬件代价;如果用软件实现则花费的周期数目较多。论文提出了一种采用静态指令翻译技术的保护测试单元来实现保护测试。由于保护测试单元提取了保护测试的共性,可以在一条保护测试指令中完成一次保护测试,因而可以在硬件增加不多的情况下高效率地实现保护测试。文中最后设计了一种保护测试指令的格式和保护测试单元的数据通路,并列举了一段保护测试程序说明了静态指令翻译的使用方法。     

Co-Processor for evolutionary full decision tree induction

In this paper a co-processor for the hardware aided decision tree induction using evolutionary approach (EFTIP) is proposed. EFTIP is used for hardware acceleration of the fitness evaluation task since this task is proven in the paper to be the execution time bottleneck. The EFTIP co-processor can significantly improve the execution time of a novel algorithm for the full decision tree induction using evolutionary approach (EFTI) when used to accelerate the fitness evaluation task. The comparison of the HW/SW EFTI implementation with the pure software implementation suggests that the proposed HW/SW architecture offers substantial DT induction time speedups for the selected benchmark datasets from the standard UCI machine learning repository database.     

Bootloader硬件保护电路设计

对当前Bootloader使用的软硬件保护方法进行研究.针对软件保护在程序运行异常时可靠性下降、传统硬件保护成本较高的情况,深入分析Bootloader实现机制和Flash擦除、烧写流程.根据数字电路逻辑设计原理,利用门级电路设计了一种新型的Bootloader硬件保护电路.与软件保护相比,在增加少量设计成本的情况下,可以极大地提高系统的安全性.与传统硬件保护相比,可以有效降低成本、提高可靠性.经验证,该电路基本可以杜绝Bootloader被误改写的缺点.     

手机二维码在多媒体教室设备管理中的应用

针对我校多媒体教室管理中存在的问题,设计开发一套多媒体教室设备管理系统。该系统采用C/S架构,基于Android平台,利用手机二维码技术,实现快速查询多媒体教室的软硬件信息以及设备操作手册,极大地提升了多媒体教室管理效率。      

基于F28335的混合动力车ABS控制系统设计

针对自主开发的四轮驱动混合动力轿车的串联式制动能量回收系统,采用DSP28335设计了ABS液压控制系统。基于制动能量回收系统的液压控制方式,介绍了该控制系统的设计原理、硬件构成,并利用Matlab自动代码生成技术,进行了软件设计。经过硬件在环实验,证明了该ABS控制系统的可行性。