共查询到20条相似文献,搜索用时 46 毫秒
1.
Ramalingam Shanmugam 《通讯和计算机》2013,(6):743-747
In this article, new probabilistic health-informatics indices connecting probabilities: Pr(A),Pr(B),Pr(A IB) and P r(A ]B-) are discovered, where .4 and B denote respectively the "ability of a hospital to treat anthrax patients" and "whether a hospital drilled to be prepared to deal with an adverse bioterrorism". These probabilistic informatics are not seen in any textbooks or journal articles and yet, they are too valuable to be unnoticed to comprehend the hospitals' preparedness to treat anthrax patients in an outbreak of bioterrorism. A demonstration of this new probabilistic informatics is made in this article with the data in the U.S. Government's General Accounting Office's report GA0-03-924. Via this example, this article advocates the importance of the above mentioned probabilistic-informatics for health professionals to understand and act swiftly to deal with public health emergencies. 相似文献
2.
Garth Herman Aleksander Milshteyn Airs Lin Manuel Garcia Charles Liu Darrell Guillaume Khosrow Radand Helen Boussalis 《通讯和计算机》2014,(5):469-477
Robots facilitate exploration of hazardous environments during response to catastrophe. Autonomous robotic platforms involved in search and rescue operations require accurate position and orientation (localization) information for self-navigation from its current position to its subsequent destination. A Hybrid Routing Algorithm Model has been proposed by the SPACE (structures, pointing and control engineering) URC (university research center) at California State University of Los Angeles. This model envisions three-layered terrain mapping with obstacle representations from various information sources such as satellites, UAVs and onboard range sensors. A* path-finding algorithm is applied to the outer two layers of the model (Layer 1 and Layer 2), while dynamic A* algorithm is responsible for innermost layer (Layer 3) navigation. The mobile robot localization information is computed using data obtained from a 9 Degrees of Freedom Inertial Measurement Unit. While gyroscope sensors provide the system the instantaneous radial velocity of a turning platform, these sensors are also susceptible to drift. Accelerometers are extremely sensitive to vibrations, and along with fluctuating magnetic fields, both accelerometers and magnetometers exhibit noisy behaviors when localizing the robot. Since the IMU contains all three sensors, a Kalman Filter is implemented on a PSoC-5 microcontroller to fuse data from the IMU sensors. This reduces standard deviation between measurements and improves reported heading accuracy, hence provides reliable information on the robot's localization and improves mapping. 相似文献
3.
It is well known that a biped robot needs actuators to walk stably on level ground. Till now, a biped robot with torso has needed at least two actuators to achieve this. Would it be possible for this kind of robot to walk on level ground with only one actuator? This paper responds in the affirmative and proposes a simple control strategy for a planar biped robot with torso. In this control method, there is only one low gain proportional-derivative (PD) controller between the torso and the stance leg, while the swing leg remains totally free. The PD controller utilizes states of both the torso (angle and angular velocity) and the stance leg. The numerical simulations show that, by adopting this controller, a planar biped robot with torso can walk stably on level ground, and that the robot can walk with a wide range of speeds and high energy efficiency by changing the control parameters. Four period-one gaits, one of which is stable while the other three are unstable, are found by simulations. According to the literature surveyed, we are the first to have a torso only driven biped robot walk stably on level ground. 相似文献
4.
The method of artificial potential field has obvious advantages among the robot path planning methods including simple structure, small amount of calculation and relatively mature in theory. This paper puts forward the "Integral method" focusing on solving the problem of local minimization. The method analyses the distribution of obstructions in a given environment and regards adjacent obstacles as a whole, By changing the parameters of the repulsive force field, robots can quickly get out of the minimum point and move to the target point. This paper uses the Simurosot platform to carry on the simulation experiment on the improved artificial potential field method, which projects a feasible path successfully and verifies this method. 相似文献
5.
Salvador Ibarra Martinez ;Jose Antonio Castan Rocha ;Julio Laria Menchaca ;Mayra Guadalupe Trevino Berrones ;Javier Guzman Obando ;Julissa Perez Cobos ;Emilio Castan Rocha 《计算机技术与应用:英文》2014,(2):91-97
Autonomous navigation is a complex challenge that involves the interpretation and analysis of information about the scenario to facilitate the cognitive processes of a robot to perform free trajectories in dynamic environments. To solve this, the paper introduces a Case-Based Reasoning methodology to endow robots with an efficient decision structure aiming of selecting the best maneuver to avoid collisions. In particular, Manhattan Distance was implemented to perform the retrieval process in CBR method. Four scenarios were depicted to run a set of experiments in order to validate the functionality of the implemented work. Finally, conclusions emphasize the advantages of CBR methodology to perform autonomous navigation in unknown and uncertain environments. 相似文献
6.
Tomas Olsson Mathias Haage Henrik Kihlman Rolf Johansson Klas Nilsson Anders Robertsson Mats Bjrkman Robert Isaksson Gilbert Ossbahr Torgny Brogrdh 《Robotics and Computer》2010,26(1):24-38
Here we present a method for high-precision drilling using an industrial robot with high-bandwidth force feedback, which is used for building up pressure to clamp-up an end-effector to the work-piece surface prior to drilling. The focus is to eliminate the sliding movement (skating) of the end-effector during the clamp-up of the end-effector to the work-piece surface, an undesired effect that is due to the comparatively low mechanical stiffness of typical serial industrial robots. This compliance also makes the robot deflect due to the cutting forces, resulting in poor hole position accuracy and to some extent in poor hole quality. Recently, functionality for high-bandwidth force control has found its way into industrial robot control systems. This could potentially open up the possibility for robotic drilling systems with improved performance, using only standard systems without excessive extra hardware and calibration techniques. Instead of automation with expensive fixtures and precise machinery, our approach was to make use of standard low-cost robot equipment in combination with sensor feedback. The resulting sliding suppression control results in greatly improved hole positioning and quality. The conceptual idea behind the force control is useful also in many other robotic applications requiring external sensor feedback control. 相似文献
7.
Waveguide design becomes more and more important with the increasing demand of efficient routing and interconnection of electromagnetic signals for advanced information technologies. Here we review the basic theory, special techniques, and potential applications of transformation optics in waveguide design. Three major design strategies of transformation optics and their limitations in waveguide applications are discussed. The recent new trends of transformation techniques by imposing specific restrictions from materials are emphasized for practical implementation. Plasmonic waveguide is used as an example to compare these transformation strategies. Applications beyond waveguides but with great practical value such as super-resolution hyperlens design are also discussed in the context of waveguiding phenomena from the perspective of transformation optics. 相似文献
8.
ZhiYuan Li 《中国科学:信息科学(英文版)》2013,56(12):1-21
Photonic crystal (PC) offers a powerful means to mold the flow of light and manipulate light- matter interaction at subwavelength scale. In this paper, we review some recent theoretical and experimental work in our group on design and fabrication of microwave and infrared PC structures with the capability to achieve various anomalous transport behaviors of light. We discuss several microwave 2D PC and quasi-crystal structures that exhibit nearly isotropic equi-frequency surface (EFS) contours with effective refractive index equal to -1. In these structures, we can observe negative refraction induced focusing of microwave against a fiat slab lens in non-neax field regions. In comparison, if PC structures have anisotropic EFS contours in the lowest photonic band, only near-field focusing is expected. We move forward to high frequency infrared band and exploreremarkable dispersion properties of silicon 2D PC slab to achieve broad-band negative refraction and self-collimation transport of infrared light beam. We also explore the possibility to realize negative refraction and flat-lens focusing of light in 3D PC made from inverse opal. These studies show that PCs can offer a powerful route to manipulate various anomalous transport of light via photonic band gap and band structure engineering, which can be harnessed to build a wide variety of integrated optical devices for large-scale optical integration. 相似文献
9.
Aiming at the series of errors processing and analyzing produced in three-dimensional testing and reconstruction of the highway pavements, this paper conducts a detailed analysis and computation of these process errors, including calibration of signalized points, centerline calculation of light stripe, accumulated system error, etc.. After the contrast experiment and analysis, it finally introduces gravity method to calculate the camera's internal parameters, and gray centroid algorithm to extract light stripes' center. Result shows the system deviation is stabilized at 2 mm, which can better meet the needs of engineering practice. 相似文献
10.
In this review, we present our recent work on making structured metals transparent for broadband electromagnetic waves by surface plasmons (SPs) or spoof surface plasmons (SSPs). First, we demonstrate that the interference between the localized and propagating SPs plays an important role in the optical transmission through arrays of sub-wavelength holes. The observed phenomena belong to the category of plasmonic Fano effects. Second, we show that the transmission enhancement originates not only from the coupling between the incident light and the excited SPs but also from the coupling among these SPs in multiple nano-aperture stacks. Finally, we demonstrate that metallic plates with narrow slit arrays can become transparent within extremely broad spectral bandwidths, and high transmission efficiency is insensitive to the thickness of the metal. This phenomenon explicitly demonstrates the conversion between light and SPs. These investigations provide guidelines to develop many novel materials and devices, such as transparent conducting panels, antireflective solar cells, and other broadband metamaterials. 相似文献
11.
脊柱椎体的多层复合结构和易热损伤特性要求手术机器人在对椎弓根进行骨钻孔时需精确控制其轴向钻削力。然而人的个体差异和脊柱-软组织构成的刚软耦合结构会使得通用型力控制器的控制精度不足,手术安全性降低。本文旨在提高轴向钻削力控制的精度。首先建立了基于质量、弹簧和Maxwell黏弹性单元的脊柱-软组织系统的刚软耦合模型。然后在离体羊脊柱上进行了应力松弛实验,并基于实测力数据对模型参数进行了标定。采用PID(比例-积分-微分)控制器来调整骨钻的轴向进给速度,并基于标定后的刚软耦合模型的传递函数,使用动态权重的标准粒子群算法整定控制器参数。最后,仿真证明闭环控制系统具有较好的动态性能和鲁棒性。离体羊脊柱骨钻孔力控制实验结果表明,轴向钻削力的阶跃力响应稳态误差小于0.15 N,相对力控制误差小于3%,且无明显超调;正弦力响应幅度在频率为3.49 rad/s时衰减到-3 d B,闭环控制系统具有较好的控制带宽。所提方法的力控制精度和控制带宽能够满足手术机器人执行骨钻削时的力跟踪要求,提高了机器人自动骨钻削过程的安全性。 相似文献
12.
王欣 《自动化技术与应用》2014,33(12):75-77
针对钻杆生产线中物料输送的特点和难点,设计了基于搬运机器人的智能输送系统,介绍了系统的组成、工作流程、以及Profibus总线配置。调试表明,该系统能够满足搬运物料的设计目的,对提高生产效率具有较高的应用价值。 相似文献
13.
The report mainly studied the crawler frame motion platform to reduce weight and increase the intensity. Report described the structural design process which using CAD/CAE technology for solid modeling, simulation analysis, parameter optimization. And it also explained the outstanding advantages of CAD/CAE technology in mechanical design as well as simulation analysis. 相似文献
14.
A logging-while-drilling (LWD) system is usually deployed in the oil drilling process in order to provide real-time monitoring of the position and orientation of a hole. Encoded signals including the data coming from down-hole sensors are inevitably contaminated during their collection and transmission to the surface. Before decoding the signals into different physical parameters, the noise should be filtered out to guarantee that correct parameter values could be acquired. In this paper, according to the characteristics of LWD signals, we propose a novel two-step filtering scheme in which a dynamic part mean filtering algorithm is proposed to separate the direct current components and a windowed limited impulse response (FIR) algorithm is deployed to filter out the high-frequency noise. The scheme has been integrated into the surface processing software and the whole LWD system for the horizontal well drilling. Some experimental results are presented to show the feasibility and good performance of the proposed two-step filtering scheme. 相似文献
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16.
深水表层钻井随钻压力与温度监测装置是监测深水表层钻井过程中井底当量循环密度(ECD)和循环温度的重要工具。通过深水表层钻井随钻压力与温度监测装置,现场技术人员可以实时掌握井下环空压力、钻柱内压和温度等工程参数,进而了解和分析井下工况,为深水表层钻井作业和动态压井钻井技术提供指导。设计的深水表层钻井随钻压力与温度监测装置以ARM为核心,利用数据采集技术和通信技术,实现了随钻压力与温度的采集传输。完成的深水表层钻井随钻压力与温度监测装置具有体积小、功耗低、抗振动和抗高温和低温的优点。监测装置已经在我国南海第一口深水井LW6—1—1井的领眼井中成功进行应用试验,验证了其在深水无隔水管钻井条件下的机械强度、稳定性、可靠性,测量得的数据能真实反映钻井工况。 相似文献
17.
Performance Evaluation of Antenna Receive Diversity in SlMO-OFDM System over Rayleigh Fading Channel
This paper represents a comparative performance evaluation of different diversity combining techniques for a SIMO-OFDM (single-input-multiple-output orthogonal frequency division multiplexing) system over Rayleigh fading channel. OFDM is a key technique for achieving high data rates and spectral efficiency requirements for wireless communication systems. But in scattering environment, the system performances are severely degraded by the effects of multipath fading and inter-symbol interference. In wireless communication systems, antenna diversity is an important technique to combat multipath fading in order to improve the system performance and increase the channel capacity. In this paper, the performance of different diversity combining techniques-SC (selection combining), EGC (equal gain combining) and MRC (maximal ratio combining) has been analyzed and compared in terms of SNR (signal to noise ratio) and BER (bit error rate) probability. The simulation results show that the maximal ratio combining technique provides maximum performance improvement relative to all other combining schemes by maximizing the SNR of SIMO-OFDM system at the combiner output. The analytic expressions of error probability and effective bit energy to noise ratio correlated with BPSK (binary phase shift keying) modulation have been derived and formulated for N-branch SC, EGC and MRC schemes. The BER characteristics for all three combining techniques are simulated in MATLAB (matrix laboratory) tool box for varying bit energy to noise ratio. Our results also derives that SNR can be improved if the number of receiving antenna is increased, which in turn reduces BER over a Rayleigh fading channel. 相似文献
18.
针对煤矿井下多款钻孔成像仪没有地面数据处理软件的现状, 在分析钻孔成像仪输出数据源的基础上, 给出了软件总体架构设计, 基于Visual Studio+SQLite设计了一款兼容多款仪器的钻孔成像仪轨迹显示软件. 该软件实现了钻孔姿态数据和图形数据的多源数据管理, 钻孔轨迹二维、三维图生成和图形操作, 钻孔柱状图的生成和操作等功能. 应用结果表明: 该软件提供了友好的人机界面, 具有较高的应用价值. 相似文献
19.
WSNs (wireless sensor networks) consist of thousands of tiny nodes having the capability of sensing, computation, and wireless communications. Unfortunately these devices are limited energy devices, that is means we must save energy as much as possible, to increase network life time as long as possible. In this paper we introduce NEER--normalized energy efficient routing protocol that increases network life time through switching between AODV protocol that depends on request-reply routing, and MRPC that depends on residual battery in routing. 相似文献
20.
Olivier Younes 《通讯和计算机》2014,(7):539-542
An incubator is an organization that supports new ventures to grow and survive during the early stages. Mainly dedicated to information technology, life science may appear to be the next hot spot for incubators. Are there stabilized good practices? Are the business models in information technology and in life science comparable when it goes to start-ups' incubation? Leveraging our experience as practitioner in this field and using an inductive methodology, this paper tends to propose simple principles to help build robust incubators in life science, and to contribute to disseminate an entrepreneurial approach through an industry still dominated by blue chips. 相似文献