共查询到20条相似文献,搜索用时 15 毫秒
1.
Virtual Reality - Manufacturing applications of virtual reality (VR) technology are growing. The challenge is to design, integrate, and evaluate VR simulation for manufacturing Systems that... 相似文献
2.
Wenzhong Shi 《International journal of remote sensing》2013,34(14):3001-3012
Image‐to‐image registration is a prerequisite step for many important applications in different disciplines. In the field of remote sensing, the launch of new high‐resolution satellites raises the need for a fast and dynamic technique for image‐to‐image registration in order to obtain full benefit from these satellites, especially for applications such as Earth monitoring and map updating. This paper presents the utilization of the Line‐Based Transformation Model (LBTM) for image‐to‐image registration following the successful use of the LBTM for the rectification of high‐resolution satellite images using linear features as control features. The developed model is similar in structure to some other point‐based transformation models. However, line segments on linear features are used first to recover the model transformation coefficients. Based on the recovered coefficients, the whole image is registered using the ordinary point‐based form of the model. Line segments on linear features have been chosen due to their existence in images regardless of the type of the land‐use covered by the images and because line segments can be easily extracted from the images. Moreover, control points may not exist or a complete match between points on images cannot be achieved. Different forms of the developed model are discussed and results using different high‐resolution satellite images from both IKONOS and QuickBird satellites are presented. The experimental results of the new technique show high integrity of the new model and indicate that image‐to‐image registration by LBTM is reliable. 相似文献
3.
Design and implementation of a workflow-based resource broker with information system on computational grids 总被引:1,自引:0,他引:1
The grid is a promising infrastructure that can allow scientists and engineers to access resources among geographically distributed
environments. Grid computing is a new technology which focuses on aggregating resources (e.g., processor cycles, disk storage,
and contents) from a large-scale computing platform. Making grid computing a reality requires a resource broker to manage
and monitor available resources. This paper presents a workflow-based resource broker whose main functions are matching available
resources with user requests and considering network information statuses during matchmaking in computational grids. The resource
broker provides a graphic user interface for accessing available and the appropriate resources via user credentials. This
broker uses the Ganglia and NWS tools to monitor resource status and network-related information, respectively. Then we propose
a history-based execution time estimation model to predict the execution time of parallel applications, according to previous
execution results. The experimental results show that our model can accurately predict the execution time of embarrassingly
parallel applications. We also report on using the Globus Toolkit to construct a grid platform called the TIGER project that
integrates resources distributed across five universities in Taichung city, Taiwan, where the resource broker was developed.
相似文献
Po-Chi ShihEmail: |
4.
Design and Implementation of a Novel Spherical Mobile Robot 总被引:1,自引:0,他引:1
Saber Mahboubi Mir Masoud Seyyed Fakhrabadi Ahmad Ghanbari 《Journal of Intelligent and Robotic Systems》2013,71(1):43-64
In this paper, the design, modeling and implementation of a novel spherical mobile robot is presented. The robot composes of a spherical outer shell made of a transparent thermoplastic material, two pendulums, two DC motors with gearboxes, two equipments for linear motion and two control units. It possesses four distinct motional modes including: driving, steering, jumping and zero-radius turning. In driving and steering modes, the robot moves along straight and circular trajectories, respectively. The robot performs these motional modes using movable internal masses. In the jumping mode, it can jump over obstacles and in the zero-radius turning mode, the robot can turn with zero-radius to improve the motion flexibility. Furthermore, the attempts to establish the dynamic models of some motional modes are made and finally, the accuracy of the obtained dynamic models is verified by simulation and experimental results. 相似文献
5.
Cloud Computing refers to the notion of outsourcing on-site available services, computational facilities, or data storage
to an off-site, location-transparent centralized facility or “Cloud.” Gang Scheduling is an efficient job scheduling algorithm
for time sharing, already applied in parallel and distributed systems. This paper studies the performance of a distributed
Cloud Computing model, based on the Amazon Elastic Compute Cloud (EC2) architecture that implements a Gang Scheduling scheme.
Our model utilizes the concept of Virtual Machines (or VMs) which act as the computational units of the system. Initially,
the system includes no VMs, but depending on the computational needs of the jobs being serviced new VMs can be leased and
later released dynamically. A simulation of the aforementioned model is used to study, analyze, and evaluate both the performance
and the overall cost of two major gang scheduling algorithms. Results reveal that Gang Scheduling can be effectively applied
in a Cloud Computing environment both performance-wise and cost-wise. 相似文献
6.
This paper presents the development of the planar bipedal robot ERNIE as well as numerical and experimental studies of the
influence of parallel knee joint compliance on the energetic efficiency of walking in ERNIE. ERNIE has 5 links—a torso, two
femurs and two tibias—and is configured to walk on a treadmill so that it can walk indefinitely in a confined space. Springs
can be attached across the knee joints in parallel with the knee actuators. The hybrid zero dynamics framework serves as the
basis for control of ERNIE’s walking. In the investigation of the effects of compliance on the energetic efficiency of walking,
four cases were studied: one without springs and three with springs of different stiffnesses and preloads. It was found that
for low-speed walking, the addition of soft springs may be used to increase energetic efficiency, while stiffer springs decrease
the energetic efficiency. For high-speed walking, the addition of either soft or stiff springs increases the energetic efficiency
of walking, while stiffer springs improve the energetic efficiency more than do softer springs.
Electronic Supplementary Material The online version of this article () contains supplementary material, which is available to authorized users.
相似文献
R. A. BockbraderEmail: |
7.
A M-matrix which satisfies the Hecke algebraic relations is presented. Via the Yang–Baxterization approach, we obtain a unitary
solution
\breveR(q,j1,j2){\breve{R}(\theta,\varphi_{1},\varphi_{2})} of Yang–Baxter equation. It is shown that any pure two-qutrit entangled states can be generated via the universal
\breveR{\breve{R}}-matrix assisted by local unitary transformations. A Hamiltonian is constructed from the
\breveR{\breve{R}}-matrix, and Berry phase of the Yang–Baxter system is investigated. Specifically, for j1 = j2{\varphi_{1}\,{=}\,\varphi_{2}}, the Hamiltonian can be represented based on three sets of SU(2) operators, and three oscillator Hamiltonians can be obtained.
Under this framework, the Berry phase can be interpreted. 相似文献
8.
In this paper, we propose a manipulation system for agricultural robots that handle heavy materials. The structural systems
of a mobile platform and a manipulator are selected and designed after proposing new knowledge about agricultural robots.
Also, the control systems for these structural systems are designed in the presence of parametric perturbation and uncertainty
while avoiding conservative results. The validity of both the structural and control systems is confirmed by conducting watermelon
harvesting experiments in an open field. Furthermore, an explicit design procedure is confirmed for both the structural and
control systems and three key design tools are clarified.
相似文献
Satoru SakaiEmail: |
9.
This paper presents a framework for allocating radio resources to the Access Points (APs) introducing an Access Point Controller
(APC). Radio resources can be either time slots or subchannels. The APC assigns subchannels to the APs using a dynamic subchannel
allocation scheme. The developed framework evaluates the dynamic subchannel allocation scheme for a downlink multicellular
Orthogonal Frequency Division Multiple Access (OFDMA) system. In the considered system, each AP and the associated Mobile
Terminals (MTs) are not operating on a frequency channel with fixed bandwidth, rather the channel bandwidth for each AP is
dynamically adapted according to the traffic load. The subchannels assignment procedure is based on quality estimations due
to the interference measurements and the current traffic load. The traffic load estimation is realized with the measurement
of the utilization of the assigned radio resources. The reuse partitioning for the radio resources is done by estimating mutual
Signal to Interference Ratio (SIR) of the APs. The developed dynamic subchannel allocation ensures Quality of Service (QoS),
better traffic adaptability, and higher spectrum efficiency with less computational complexity.
相似文献
Chanchal Kumar Roy (Corresponding author)Email: |
10.
Dong-Ju Lee Jung-Hyun Woo No-Cheol Park Jeong-hoon Yoo Young-Pil Park Nobuaki Onagi Goichi Akanuma 《Microsystem Technologies》2009,15(10-11):1729-1735
Recently, there has been a trend to have large capacity and high data transfer rate in optical disk drive. Pickup actuator also should have high performance for satisfying this trend. Since moving magnet type actuator has more simple and robust structure than moving coil type one, we designed moving magnet type to accomplish high flexible mode frequency. However, the driving sensitivity of moving magnet type actuator was low because of its characteristics as following. At first, moving parts including magnets are heavy and electromagnetic (EM) circuits are not closed-loop owing to yoke composed of paramagnetic materials. Therefore, in order to increase the driving sensitivity without the degradation of the other dynamic characteristics, EM circuits were redesigned by adding solenoid coils on existing mechanism. As a result, the hybrid type actuator composed of moving magnet type and moving coil type was suggested to obtain high sensitivities and high flexible mode frequency. Design variables of EM circuits and structure parts were decided through parametric study and design of experiments procedure. Optimization algorithm using variable metric method was used to improve performance. Based on these results, the final model was presented. 相似文献
11.
Underwater intervention is a favorite and difficult task for AUVs. To realize the underwater manipulation for the small size spherical underwater robot SUR-II, a father–son underwater intervention robotic system (FUIRS) is proposed in our group. The FUIRS employs a novel biomimetic microrobot to realize an underwater manipulation task. This paper describes the biomimetic microrobot which is inspired by an octopus. The son robot can realize basic underwater motion, i.e. grasping motion, object detection and swimming motion. To enhance the payload, a novel buoyancy force adjustment method was proposed which can provides 11.8 mN additional buoyancy force to overcome the weight of the object in water. Finally, three underwater manipulation experiments are carried out to verify the performance of the son robot. One is carried by swimming motion and buoyancy adjustment; the other two are only carried by buoyancy adjustment. And the experimental results show that the son robot can realize the underwater manipulation of different shape and size objects successfully. The swimming motion can reduce the time cost of underwater manipulation remarkably. 相似文献
12.
Simulation of a viscoelastic flexible multibody system using absolute nodal coordinate and fractional derivative methods 总被引:2,自引:0,他引:2
This paper employs a new finite element formulation for dynamics analysis of a viscoelastic flexible multibody system. The
viscoelastic constitutive equation used to describe the behavior of the system is a three-parameter fractional derivative
model. Based on continuum mechanics, the three-parameter fractional derivative model is modified and the proposed new fractional
derivative model can reduce to the widely used elastic constitutive model, which meets the continuum mechanics law strictly
for pure elastic materials. The system equations of motion are derived based on the absolute nodal coordinate formulation
(ANCF) and the principle of virtual work, which can relax the small deformation assumption in the traditional finite element
implementation. In order to implement the viscoelastic model into the absolute nodal coordinate, the Grünwald definition of
the fractional derivative is employed. Based on a comparison of the HHT-I3 method and the Newmark method, the HHT-I3 method
is used to solve the equations of motion. Another particularity of the proposed method based on the ANCF method lies in the
storage of displacement history only during the integration process, reducing the numerical computation considerably. Numerical
examples are presented in order to analyze the effects of the truncation number of the Grünwald series (fading memory phenomena)
and the value of several fractional model parameters and solution convergence aspects.
An erratum to this article can be found at 相似文献
13.
Yi He Fengman Liu Fengze Hou Peng Wu Jun Li Liqiang Cao Dongkai Shangguan 《Microsystem Technologies》2014,20(12):2295-2300
In this paper, we present a complete 700–2,600 MHz RF SiP module for micro base station. This RF SiP design integrates transmitter, receiver, feedback module, ADC/DAC and CLK module. The module consists of two multi-layer organic substrates that are vertically stacked using BGA interconnections. With the integration of 33 chips and about 600 passive components, this RF SiP module retains small form factor and measures 5.25 cm × 5.25 cm × 0.7 cm. The RF input signal transmission path insertion loss is less than 0.34 dB and the return loss is less than ?14 dB at 2.6 GHz. Full load thermal simulation result indicates that each chip junction temperature is below 100 °C. We summarize the RF SiP module design, assembly and simulated thermal characteristics. The proposed RF SiP can generally be characterized by small size, low cost and short development cycle. 相似文献
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15.
The kinematics/statics and workspace of a 2(SP+SPR+SPU) serial–parallel manipulator are studied systematically. First, a 2(SP+SPR+SPU)
manipulator including an upper and a lower SP+SPR+SPU parallel manipulators is constructed, and the inverse/forward displacements,
velocity, acceleration and statics of the lower/upper parallel manipulators are studied, respectively. Second, the kinematics
and statics of the lower/upper manipulators are combined and the displacement, velocity, acceleration, statics, and workspace
of a 2(SP+SPR+SPU) manipulator are analyzed systematically. Third, the analytic solutions’ examples are given and verified
by the simulation mechanism. This manipulator has some potential applications for the robot’s arm, leg, and twist, the serial–parallel
machine tools, the sensor, the surgical manipulator, the tunnel borer, the barbette of warship, and the satellite surveillance
platform. 相似文献
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17.
Hamid Dolatshahi Pirooz Ata A. Eftekharian Alireza Mohammad Shahri Mohammad Eftekhari Yazdi 《Advanced Robotics》2014,28(24):1677-1689
This paper presents the design and implementation of a novel joint-based magnetic actuator for robotic manipulators using variable stiffness mechanism. This new actuator prototype, namely M2-VSA, is developed as an improvement over previous actuators in its class. The robotic arm with M2-VSA joint can safely interact with human operators and work in hazardous conditions. The main novelty in this work is the use of magnetic force in accompanying with springs in a novel arrangement to adjust the joints’ stiffness and mitigate the effect of impact. The theoretical framework and advantages of the design are discussed in detail. Experimental studies through various tests show the effectiveness and efficiency of mechanical–magnetic joint as a safe mechanism in environments where human and robotics have interaction. 相似文献
18.
High spatial and spectral resolution thermal infrared imagery (8.0-13.5 μm) from the SEBASS airborne sensor was used to analyze and map tree canopy spectral features at the State Arboretum of Virginia, near Boyce, Virginia. Fifty tree species were analyzed and about half were directly identified with varying degrees of success on the basis of spectral matched filtering that utilized laboratory-measured leaf spectra as the target signatures. Spectral averages of pixels extracted from SEBASS emissivity data compared favorably with laboratory spectra of leaves collected from individual tree species. Best results were obtained from species having relatively strong spectral contrast, wide and flat leaves, closed planophile canopies, and/or large canopy areas. Tree species having small leaves or unfavorable leaf orientations showed spectral attenuation likely resulting from cavity blackbody effects. Increased spatial resolution and better image calibration and atmospheric correction might lead to further improvements in thermal infrared plant species identification. 相似文献
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S. Lacherade C. Miesch X. Briottet H. Le Men 《International journal of remote sensing》2013,34(17):3859-3866
This letter presents an experiment carried out in Toulouse in May 2004 to study the spectral variability and bidirectional reflectance behaviour of urban materials. The measurements were carried out at a 20 cm spatial resolution in the visible and near‐infrared (350–2500 nm). These measurements allow quantification of three main types of reflectance spatial variability. In addition to these in situ experiments, the bidirectional properties of urban material samples were studied in the laboratory with a goniometer. 相似文献