共查询到20条相似文献,搜索用时 15 毫秒
1.
V. I. Guz’ V. I. Markov A. A. Zaitsev V. A. Martynov A. B. Filonenko 《Radioelectronics and Communications Systems》2007,50(1):31-34
The paper presents a classification of contemporary methods for measurement of PAA characteristics, potentialities of their development and hardware implementation. The emphasis is made on diagnostic of PAA technical state, on determination of amplitude-phase distribution (APD) over the aperture, and on PAA adjustment procedures. The paper considers technical characteristics of automated measurement systems (AMS) and of the relevant equipment. Examples of AMS application for PAA parameter determination are included. 相似文献
2.
《Mechatronics》2016
Nowadays, a large number of AGVs are needed to carry out repeating transport tasks in many manufacturing and warehouse industries. Their extensive application is influenced by several critical factors of equipment expense, vehicle maneuverability, energy efficiency and configuration flexibility, especially in a large-scale AGV system. In order to attain high dynamics and energy conservation while retaining low cost and flexible reconfiguration, mechatronics techniques are introduced to combine high-performance microcontrollers, low-power motors and short-range sensors with a light-weighted chassis, which results in a swift mechatronic tractor for automated guidance of a heavy-duty robotic vehicle on fixed guide paths. Analysis of load carrying for different wheels shows the tractor only carries a partial weight of the whole vehicle by using its suspension layer. Kinematics and dynamics properties of the vehicle actuated by the tractor are investigated, which explains the reasons why low-power motors and short-range sensors can be used for automated guidance of heavy-duty vehicles. When this tractor is equipped with different guiding sensors, such as a magnetic sensor or a camera, the corresponding magnetic or visual guided vehicle can be conveniently developed only by configuring tractors and other passive wheels within a vehicle frame. For instance, a low-cost magnetic sensor is used for the tractor and a magnetic guided vehicle prototype is developed based on it. Experiments of load carrying and path tracking are conducted by using this prototype. The experiment results show the tractor can actuate the heavy-duty vehicle with low power consumption and track its target paths with a fast dynamic response, which provides a possibility of decreasing cost and consumption still preserving maneuverability and flexibility by using mechatronics techniques. 相似文献
3.
《Proceedings of the IEEE. Institute of Electrical and Electronics Engineers》1969,57(11):1961-1973
PRIME is an acronym for a subject-oriented computer-based information storage and retrieval system which uses variable length, variable content, natural language, data collection forms. PRIME was developed as a model of a hospital automated information system and has been in operation since March 1965. Experience with this model system has shown that it is important to spend time planning the management and use of the computer system before the system is installed. Education programs for medical staff members and researchers are well worth the effort because it does take effort to get professional staff members to use a computer system. Data collection forms should be designed by the individual who uses them. It helps him to organize his thoughts about his project. Some conclusions about the administrative aspects of an automated information system in a hospital are presented. 相似文献
4.
An approach to the design of a robot system capable of executing complex sensory-motor sequences aimed at gathering data useful for diagnostic purposes is presented. The main features of such a robot system are discussed, and its possible integration in an advanced, interactive expert system for medical diagnosis is considered. As an example of implementation of the concept of a robot system for automated diagnostic tasks, the design characteristics of a tendon-actuated, anthropomorphic finger, incorporating force and position sensors for low-level compliant motion control and skin-like sensors for tactile perception, are outlined. The hierarchical control architecture devised for managing some different diagnostic sensory-motor sequences (subroutines) is also presented 相似文献
5.
Parallel and distributed simulation (PDS) is often employed to tackle the computational intensity of system-level simulation of real-world complex embedded and cyber-physical systems (CPSs). However, CPS models comprise heterogeneous components with diverge semantics for which incompatible PDS approaches are developed. We propose an automated PDS flow based on a formal modeling framework—with necessary extensions—targeting heterogeneous embedded and CPS design. The proposed flow characterizes the sequential executable specification of a heterogeneous model and generates a PDS cluster. State-of-the-art graph partitioning methods are adopted and a new extensible constraint-base formulation of the model partitioning problem is developed. The applicability, effectiveness, and scalability of the proposed flow is demonstrated using case studies. 相似文献
6.
Bonte B. Gaquiere C. Bourcier E. Lemeur G. Crosnier Y. 《Microwave Theory and Techniques》1998,46(1):70-75
An active load-pull system is presented for measuring devices from 50-μm to 3-mm gatewidth in Ka-band. It can automatically scan the interesting area of the Smith chart. The system protects the tested devices because the impedance is presented at the output of the device only if the gate current is lower than a fixed value. Results are presented at 30 and 38 GHz on a pseudomorphic high electron-mobility transistor (PM-HEMT) 相似文献
7.
《Vehicular Technology, IEEE Transactions on》1984,33(2):51-57
An automated electromagnetic-field strength measurement system and its applications are described which are for the purpose of mapping the electromagnetic-field strength distribution inside and outside vehicles exposed to electromagnetic field. The system is comprised of three subsystems: electromagnetic-field generation unit, data transmission stage using a magnetic-field probe and a fiber-optic link, and data control/processing stage consisting of a graphic computer and peripherals. The system is capable of measuring field strength levels between 40 and 85 dBµA/m with errors within ± 1 dB in a frequency range of 20-200 MHz. The time required for making measurements at a single measurement point at intervals of 2 MHz from 20 to 200 MHz is about three min. Magnetic-field strength measurements at every interior position of a vehicle exposed to electromagnetic fields inside an anechoic chamber were made using this system. The field strength of the vehicle interior was found to vary with the polarization of an electromagnetic wave, the direction of irradiation, and the body shape of the vehicle. 相似文献
8.
在数据加卸载系统上,为了防止对数据的非法操作,需要数据加卸载卡具备一定的安全验证功能。本文在分析USB批量传输协议的基础上,设计了数据卡的固件程序状态机,在固件程序中增加具有验证功能的自定义CBWCB命令来实现数据卡安全验证功能。最后通过数据加卸载系统完成对数据加卸载卡的安全验证实验,证明该方法简单、可靠。 相似文献
9.
An automated open resonator system was designed and constructed for precision measurement of the loss tangent and dielectric permittivity of low absorbing materials at 60 GHz. The use of a high-Q hemispherical Fabry-Perot cavity together with highly stabilized synthesized phase-locked Gunn oscillator sources and a superheterodyne receiver made it possible to measure loss tangent values as low as 10 μrad. Both cavity length variation and frequency variation techniques were utilized to provide precise data 相似文献
10.
导向系统是磁浮列车的三大核心子系统之一,属于多学科交叉的复杂问题,具有重大研究价值。文章以常导吸引型(EMS)磁浮列车的导向系统为研究对象,综合运用物理运动学、电磁学、电工学以及控制学等多学科理论,推导得到导向系统的非线性模型。为便于后续研究,采用泰勒级数法对所得模型进行了线性化处理,并分析了系统的稳定性。 相似文献
11.
The author presents an overview of a methodology for the automated generation of fault trees for electrical/electronic circuits from a representation of a schematic diagram. Existing computer programs for the generation of fault trees are briefly discussed, and their deficiencies are indicated. The approach presented here is quantitative and uses backtracking. It is illustrated by an example. A prototype computer program has been written to implement the methodology for DC circuits 相似文献
12.
《Latin America Transactions, IEEE (Revista IEEE America Latina)》2007,5(6):409-416
Local e-marketplaces are local online e-commerce platforms deployed by product and service providers and accessed by local customers via mobile devices. In this scenario, customers need to gather information about available offers from the different providers in the area, in order to select the most suitable for their needs and preferences. We present ANEGSYS, an agent-based recommender system for product acquisition which uses automatic bilateral negotiations to generate purchase pre-agreements among buyer and seller agents. This greatly enhances the search for solutions which maximize both buyer and seller utilities. 相似文献
13.
Qishan Yu Gandhi O.P. Aronsson M. Ding Wu 《Electromagnetic Compatibility, IEEE Transactions on》1999,41(3):234-245
An automated specific absorption rate (SAR) measurement system has been developed for compliance testing of personal wireless devices. Unlike other systems, this system uses a model with a lossy ear-shaped protrusion and the accuracy of this experimental setup has been checked by comparing the peak 1-g SARs for ten cellular telephones, five each at 835 and 1900 MHz, with the results obtained using a 15-tissue anatomically based model with the finite-difference time-domain (FDTD) numerical electromagnetic technique. The SAR measurement system uses a three-dimensional (3-D) stepper motor to move a Narda Model 8021 E-field probe to measure the SAR distribution inside a head-shaped tissue-simulant phantom near the radiating device. The head and neck part of the model with an ear-shaped protrusion of 3 mm thickness is made of a lossy outer shell of 5-7 mm thickness of epoxy laced with KCl solution. The phantom is filled with appropriate frequency-specific fluids with measured electrical properties (dielectric constant and conductivity) that are close to the average for gray and white matters of the brain at the center frequencies of interest (835 and 1900 MHz). The implantable E-field probe is calibrated using the FDTD-calculated SAR variations for a slab model at two commonly used frequencies, 835 and 1900 MHz and is checked to have good isotropic characteristics (±0.23 dB) and a wide dynamic range (0.01-10 W/kg). The system is validated using a 223-mm-diameter sphere model. Peak 1-g SAR's for ten telephones using different antennas are within ±1 dB of those obtained using the FDTD numerical method for the anatomical model of the head and neck region 相似文献
14.
SYNCHROTRAC is a power control system that provides longitudinal control of vehicles by a unique method in which it distributes power to those vehicles. The vehicles are passive (control-wise) in that power modulation is accomplished by the vehicle's position within the traveling control section. Therefore, no on-board power modulation or communication equipment is required. The SYNCHROTRAC system can be readily employed in a wide variety of transportation applications. It is adaptable to the closed-circuit moving sidewalk applications that require slow captive vehicles operating with small headways as well as to the independently routable dual-mode application that requires fast vehicles operating with small headways. The specific vehicle design can vary to suit a particular application requiring only that the motive drive be an induction motor providing the appropriate vehicle dynamic response, i.e., voltage and frequency versus torque. 相似文献
15.
针对多用户正交频分复用(OFDM)系统资源分配问题,提出了一种改进的基于边缘自适应(MA)准则的子载波和比特分配算法。在采用比例公平准则为每个用户分配子载波集合基础上,以用户速率最大者-最小者(Max-Min)子载波交换为原则进行子载波调整,使用户功率递减同时兼顾用户的公平性;通过对信道状态信息进行判断,利用贪婪算法将用户子载波分配的比特取整,以实现系统功率最小化。实验结果表明,本文提出的改进次优算法的计算复杂度较传统分步算法稍高,但仍远低于最优算法,其系统性能得以提升,且接近最优算法。 相似文献
16.
Venot A Devaux JY Herbin M Lebruchec JF Dubertret L Raulo Y Roucayrol JC 《IEEE transactions on medical imaging》1988,7(4):298-303
A system is presented for digitization and automated comparison of photographic images of patients obtained at different times using a high-precision video camera. The images can be acquired either directly or from slides. The two images to be compared are registered using a complex geometrical and gray-level registration model including six parameters (planar, translation, rotation, magnification, linear transformation of the gray levels). The values of the registration parameters are automatically calculated by maximizing an integer similarity measure selected for robustness. The optimization of this function with respect to the registration parameters is performed using an adaptive random search strategy. The analysis of the differences between the registered images can be carried out through visual inspection of the subtraction image in which artifacts due to remaining infrapixel shifts have been suppressed. 相似文献
17.
Bhattacharya S.K. Bhatevara S. Morales H. Kauffman S. Kamen E. May G.S. 《Electronics Packaging Manufacturing, IEEE Transactions on》2000,23(4):267-276
Material deposition techniques can be a significant contributor to the overall electronics manufacturing costs. The present study evaluates meniscus coating as a low-cost tool for large-area polymer deposition. Meniscus coating has the following advantages over conventional spin coating: (1) minimal material waste; (2) higher throughput; (3) higher planarity; (4) minimal defect density; (5) thickness uniformity over a large area. Each of these factors help reduce the overall manufacturing costs. The objective of this effort is to develop, install, and qualify an automated, low-cost, high-throughput polymer deposition method for large area MCM-D and MCM-L substrates. A variety of polymer photoresists, dielectrics, and composites are used for thick film coating on 12 in PWB and glass substrates. For each material, the deposition process is optimized to the desired film thickness. In this paper, we report materials and process optimization for 12 in×12 in substrates that is scalable to 24 in×24 in substrates. For higher throughput and lower manufacturing cost, an automated coating workcell is designed. The proposed workcell includes a robotic material handling and convection drying of coated films with automated loading/unloading capability. Design and fabrication of the integrated workcell are also addressed 相似文献
18.
《Vehicular Technology, IEEE Transactions on》1979,28(1):46-55
An important aspect in the design of automated guideway transit (AGT) systems is the communication requirements for the longitudinal control of vehicles, that is, the requirements to measure vehicle states, transmit this information between vehicles, and subsequently control the individual vehicles. This paper examines the trade-offs in the data rates, word lengths, and allowable transmission time lags needed to maintain an acceptable level of vehicle performance, and how these requirements relate to the allocation of control computation between vehicle- and wayside-based computers. A nonlinear control law designed for short-headway vehicle-follower systems provides a baseline to examine these trade-offs. The specification of the parmeters entering the problem is approached through analytically derived results, using simplified linear models with verification and expansion of these results through a detailed simulation. 相似文献
19.
提出一种适用于OFDM系统的自适应加载算法。此算法与现有的已知算法相比,方法简单,运算量小。计算机仿真表明,采用此算法在系统性能增益基本不变的条件下,可以大大降低计算量。 相似文献
20.
Bowie L.A. Hickox M.A. Sripad A.B. 《Selected Areas in Communications, IEEE Journal on》1988,6(8):1350-1358
The purpose of repair tracking (RT) is to provide ongoing feedback of product reliability performance in the customer environment. The authors present an RT technique and provide an overview of its automated software implementation, which has been used to track several transmission system products. The RT implementation, referred to as the repair equipment analysis program (REAP), tracks the field performance of electronic equipment at system, subsystem, circuit pack, and component levels. The features of REAP include monthly reliability performance reports, alarms when degradation in performance is detected, model sensitivity analysis, problem areas isolation for initiating corrective actions, and specific customer performance studies. The approach encompasses the entire population during the product life using existing sales and repair data as main inputs. Further, it does not require customer involvement or product serialization 相似文献