Peripheral emulation extends equipment life [ATE]

The ATE industry can benefit greatly by becoming better informed about the availability, functionality, and reliability of emulated peripheral solutions. Emulated peripherals provide the ability to dramatically extend the life of aging ATE equipment, while making that equipment more reliable, more functional, much easier to use, and much simpler to support. The use of emulated disk drives and tape drives can completely eliminate persistent maintenance headaches, increase ATE station availability and reliability, and provide a reasonably priced technology refresh without costly software modifications or system recertification.     

Sustained data recording system based on disk array

Most sustained data recording systems in many real-time fields are based on tape equipments. We have developed an innovative sustained data recording system based on disk array which consists of Array Controller Module (ACM), String Controller Module (SCM) and Main Controller Module (MCM). This system has a better performance and higher reliability than the traditional tape recorder and can be used conveniently in many areas of data recording, storing, playback, and remote backup. This novel recording system has been used in radar data recorder for spacecraft orbit tracking and satellite remote sensing data recording successfully.     

基于VxWorks的惯性平台测试系统构建及BSP设计

本文提出了一种基于VxWorks的惯性平台测试计算机系统的构建方案,并设计了相应的BSP。该方案是以工控机为基础,通过添加PCI设备进行功能扩充,添加的PCI设备有以太网设备、RS-422通讯设备、MIL-STD-1553B通讯设备,此外还添加了一块并口硬盘。这种方案将工控机的强大计算能力与VxWorks实时特性相结合,并使工控机具有网络通讯、RS-422通讯、MIL-STD-1553B通讯、大量数据存储等功能,同时这种方案具有低成本、易实现的优点。     

The development of a digital video motion detection test set

This paper describes the current effort to develop a standardized data set, or suite of digital video sequences, that can be used for test and evaluation of digital video motion detectors (VMDs) for exterior applications. We have drawn from an extensive video database of typical application scenarios to assemble a comprehensive data set. These data, some existing for many years on analog videotape, have been converted to a reproducible digital format and edited to generate test sequences several minutes long for many scenarios. Sequences include non-alarm video, intrusions and nuisance alarm sources, taken with a variety of imaging sensors including monochrome CCD cameras and infrared (thermal) imaging cameras, under a variety of daytime and nighttime conditions. The paper presents an analysis of the variables and estimates the complexity of a thorough data set. Some of this video data test has been digitized for CD-ROM storage and playback. We are considering developing a DVD disk for possible use in screening and testing VMDs prior to government testing and deployment. In addition, this digital video data may be used by VMD developers for further refinement or customization of their product to meet specific requirements. These application scenarios may also be used to define the testing parameters for future procurement qualification. A personal computer may be used to play back either the CD-ROM or the DVD video data. A consumer electronics-style DVD player may be used to replay the DVD disk. This paper also discusses various aspects of digital video storage including formats, resolution, CD-ROM and DVD storage capacity, formats, editing and playback     

机载固态硬盘的IDE接口设计

机载设备的数据处理往往需要大容量的固态存储器,目前大容量FLASH存储阵列和机载计算机之间的数据交换还没有形成统一的接口标准,接口设计也因为不同的设计者和应用场合而差异多样,这在一定程度上影响了FLASH存储阵列在机载数据存储中的发展和应用。在FLASH存储阵列和计算机主机数据传输的几种接口形式中,IDE接口具有实现技术较为简单、兼容性强等优点。采用FPGA设计并实现固态IDE接口,实现FLASH存储阵列和主机之间的数据传输,标准固态IDE接口的设计实现有助于促进FLASH大容量存储阵列的发展和应用。     

立式轮盘变幅循环旋转试验器

为了较精确地预示轮盘低循环疲劳寿命,我们将轮盘超转、破裂试验器改造成应用微机自动控制的变幅循环旋转试验器,成功地完成了一个轮盘的变幅低循环疲劳旋转试验,给出了轮盘幅板偏心孔的裂纹起始寿命和扩展寿命。      

Comparison of AC drives for electric vehicles-a report on experts'opinion survey

It is recognized that wide applications of electric vehicles (EVs) will bring tremendous social, economical and ecological benefits. With the growing interests in electric vehicles, much effort is demanded for the development of efficient, reliable and economical AC drives' for EV propulsion purpose. Both induction motor (IM) drives and permanent magnet brushless DC motor (IM) drives have been applied to EVs. Switched reluctance motor (SRM) drives have been proposed as an alternative for EV propulsion. In order to assess the suitability of IM, BDCM and SRM drives for EV applications and to provide a technical support for the development and selection of future EV propulsion systems, the existing EV AC propulsion drives were compared, and a survey of experts' opinions was conducted. Comparison of the three AC drives was made on a relative and a quantitative basis using the survey questionnaires. According to the majority of the experts, induction motor drives are best suited for EV propulsion purpose, due to their low cost, high reliability, high speed, established converter and manufacturing technology, low torque ripple/noise and absence of position sensors. BDCM drives feature compactness, low weight and high efficiency and therefore provide an alternative for EV propulsion. The experts regard insulated gate bipolar transistors (IGBTs) as the most suited power semiconductor devices for AC drive converters at the present stage     

基于原子事务组的备份方案的研究与设计

备份两大主流技术：镜像技术和快照技术。镜像技术能够高速有效地访问数据,快照技术能够以较小容量迅速地存储数据。存储对象作为这两种技术的基础,对数据的完整性和高可用性起着至关重要的作用。针对单盘和磁盘组作为存储对象的不足,阐述了原子事务组作为存储对象的备份方案,较好地解决了在大型的业务系统中数据的一致性和完整性。     

Research on vibration suppression of a mistuned blisk by a piezoelectric network

The work aims to provide a further investigation of the dynamic characteristics of an integral bladed disk(also called ‘blisk') with a Parallel Piezoelectric Network(PPN). The PPN is constructed by parallelly interconnecting the piezoelectric patches distributed in the blisk. Two kinds of PPN are considered, namely mono-periodic PPN and bi-periodic PPN. The former has a piezoelectric patch in each sector, and the later has one patch every few sectors. The vibration suppression performance of both kinds of PPN has been studied through modal analysis, forced response analysis, and statistical analysis. The research results turn out that the PPN will only affect mechanical frequencies near the electrical frequency clusters slightly, and the bi-periodic PPN will make the nodal diameter spectrum of the modes more complex, but the amplitude corresponding to the new nodal diameter component is much smaller than that of the nodal diameter component corresponding to the mono-periodic system. The mechanical coupling between the blades and the disk plays an important role in the damping effect of the PPN, and it should be paid attention to in applications. The mono-periodic PPN can effectively suppress the amplitude magnification of the forced response induced by the mistuning of the blisk; meanwhile, it can mitigate the vibration localization of the mistuned electromechanical system. If piezoelectric patches are set only in part of the sectors, the bi-periodic PPN still has a vibration suppression ability, but the effect is related to the number and spatial distribution of the piezoelectric patches.     

On the “Galactic Habitable Zone”

The concept of Galactic Habitable Zone (GHZ) was introduced a few years ago as an extension of the much older concept of Circumstellar Habitable Zone. However, the physical processes underlying the former concept are hard to identify and even harder to quantify. That difficulty does not allow us, at present, to draw any significant conclusions about the extent of the GHZ: it may well be that the entire Milky Way disk is suitable for complex life.     

基于ANSYS的多辐板风扇盘结构 优化设计技术

基于ANSYS优化平台,建立了风扇盘子午面优化设计模型,筛选了主要的优化设计变量.针对典型风扇盘设计问题,分别进行了单辐板及多辐板结构优化设计.结果表明,在满足轮盘变形、强度要求的条件下,多辐板风扇盘比单辐板风扇盘可明显减轻质量,并且其应力分布更为均匀,说明对于轮缘较宽的风扇盘,多辐板轮盘结构具有明显优越性.同时,多辐板轮盘结构还有利于增强轮缘弯曲刚度.      

Access control system with hand geometry verification and smartcards

An access control system that joins the uniqueness of biometric verification, as well as the storage security and processing capabilities of smart cards, is defined here. The biometric technique chosen has been hand geometry, which is considered to provide low/medium security (there are other much more secure, as fingerprint, iris or retina), to be easy to use, to achieve high acceptance by users, and which performance is given throughout fast processing and medium cost. Also, the small template size needed for each user is positive for storage and processing capabilities required in the system. But the innovation in the system proposed is that the smart card not only stores the user's template, but also performs the verification process with the features set by the terminal to the card. With this improvement, the security of the system has risen because the template is never extracted from the card, avoiding duplication of such sensible data. The specifications for the enrolment process will be presented as well as the applications where this new system is recommended     

失调叶片盘的振动机理

本文对于失调叶片盘的耦合振动问题 ,采用子结构模态综合法建立系统的振动微分方程 ,利用试验模态分析及模态修正计算求得调谐叶片和外缘带锥壳轮盘的若干低阶模态。通过对叶片模态刚度的微量摄动 ,构造真实的失调叶片盘和各种理论分析失调模型。对某个实际的失调叶片盘的非旋转强迫振动试验验证了系统的力学模型和计算公式。计算结果分析表明 ,失调叶片盘强迫振动响应中个别叶片振动过甚乃为叶片失调所致。对各种失调模型的振动计算表明 ,小频差的随机失调优于其他失调分布形式。并就算例给出了最佳频差幅值和恰当的发动机工作频率范围。     

Analysis of an adaptive CFAR detector in non-Gaussian interference

Coherent signal detection in non-Gaussian interference is presently of interest in adaptive array applications. Conventional array detection algorithms inherently model the interference with a multivariate Gaussian random vector. However, non-Gaussian interference models are also under investigation for applications where the Gaussian assumption may not be appropriate. We analyze the performance of an adaptive array receiver for signal detection in interference modeled with a non-Gaussian distribution referred to as a spherically invariant random vector (SIRV). We first motivate this interference model with results from radar clutter measurements collected in the Mountain Top Program. Then we develop analytical expressions for the probability of false alarm and the probability of detection for the adaptive array receiver. Our analysis shows that the receiver has constant false alarm rate (CFAR) performance with respect to all the interference parameters. Some illustrative examples are included that compare the detection performance of this CFAR receiver with a receiver that has prior knowledge of the interference parameters     

Resonantly Excited Non-linear Density Waves in Disk Systems

Most of the disk systems are characterized by spiral structures. A good portion of these spiral structures can be identified as waves resonantly excited by a perturber in or pertaining to the same system. For planetary rings, this is an exterior satellite; for galactic disks, a rotating bar; for proto-stellar disks (yet to be confirmed), this would be a proto-planet. These waves, not just responsible for the present morphology of the disks, also play a dominating role on evolution of the disks. Resonance excitation is a extremely effective mechanism. A relatively weak perturbation can result in a highly non-linear responses in the disk. Therefore, non-linear theory is a necessity here. We will examine the non-linear theory of resonance excitation and discuss the applications of the theory to Saturn's rings and disk galaxies in this paper.     

热处理对Bi超导带材微结构和J_C值的影响

采用粉末装管加工技术（Ｐｏｗｄｅｒ－ｉｎ－ｔｕｂｅｔｅｃｈｎｉｑｕｅ）制备出了ＢｉＰｂＳｒＣａＣｕＯ／Ａｇ复合超导带材。研究了热处理对带材微观结构和临界电流密度（Ｊ＿ｃ）的影响。试验表明,合理的热处理温度范围为８４０～８５０℃,冷却速率为５０～１００℃／ｈ。     

基于BP神经网络和遗传算法的结构优化设计

现代航空发动机不断追求提高推重比,优化其零部件的结构设计日益重要。传统结构优化方法耗时多且不易掌握。针对这一问题,本文提出了将BP神经网络和遗传算法相结合用于结构优化设计的方法,并编制了相应的计算程序,实现了一个含9个设计变量的发动机盘模型的结构优化计算。计算证明,与传统结构优化方法相比,此方法计算速度快、精度良好。      

Some Effects of Hard Limiting in Adaptive Antenna Systems

Adaptive antennas are often implemented with the Applebaum-Howells-type adaptive processor usually include a hard limiter between each antenna port and its correlation mixer, primarily for dynamic range compression. Brennan and Reed [3] analyzed the effects of hard limiting, and their conclusions suggest that it does not degrade the steady-state performance of the adaptive processor. Standard and hard-limited processors are compared and it is shown that when the two types of processor have the same sensitivity threshold, the hard-limited one can fail to provide sufficient interference cancellation when the correlation matrix of input signals has two or more eigenvalues of differing magnitudes. The consequence of hard limiting is that (depending on the processor design parameters) the larger of two or more signals can capture the hard limiter, allowing the smaller signals to pass through the processor essentially unattenuated. It is also shown that when a hard-limited processor is designed to provide the same cancellation as a standard one, it must have essentially as large a dynamic range as the standard, processor; therefore, it offers no advantage of dynamic range compression. Moreover, the hard-limited processor lacks a constant sensitivity threshold, which can be a desirable feature of a standard processor. Specific examples are presented for identical-element array antennas and for multiple-beam antennas.     

Observed Aspects of Reconnection in Solar Eruptions

The observed magnetic field configuration and signatures of reconnection in the large solar magnetic eruptions that make major flares and coronal mass ejections and in the much smaller magnetic eruptions that make X-ray jets are illustrated with cartoons and representative observed eruptions. The main reconnection signatures considered are the imaged bright emission from the heated plasma on reconnected field lines. In any of these eruptions, large or small, the magnetic field that drives the eruption and/or that drives the buildup to the eruption is initially a closed bipolar arcade. From the form and configuration of the magnetic field in and around the driving arcade and from the development of the reconnection signatures in coordination with the eruption, we infer that (1) at the onset of reconnection the reconnection current sheet is small compared to the driving arcade, and (2) the current sheet can grow to the size of the driving arcade only after reconnection starts and the unleashed erupting field dynamically forces the current sheet to grow much larger, building it up faster than the reconnection can tear it down. We conjecture that the fundamental reason the quasi-static pre-eruption field is prohibited from having a large current sheet is that the magnetic pressure is much greater than the plasma pressure in the chromosphere and low corona in eruptive solar magnetic fields.     

Ultra-lightweight space power from hybrid thin-film solar cells

The development of hybrid inorganic/organic thin-film solar cells on flexible, lightweight, space-qualified, durable substrates provides an attractive solution for space power generation with high mass specific power (W/kg). The high-volume, low-cost fabrication potential of organic cells will allow for square miles of solar cell production at one-tenth the cost of conventional inorganic materials. Plastic solar cells take a minimum of storage space and can be inflated or unrolled for deployment. We explore a cross-section of NASA in-house and sponsored research efforts that aim to provide new hybrid technologies that include both inorganic and polymer materials as active and substrate materials. For NASA applications, any solar cell or array technology must not only meet weight and AMO efficiency goals, but also must be durable enough to survive launch and space environments. Also, balance of system technologies must be developed to take advantage of ultra-lightweight solar arrays in power generation systems.