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81.
Carlos A. Acosta Calderon Rajesh E. Mohan Lingyun Hu Changjiu Zhou Huosheng Hu 《Robotics and Autonomous Systems》2009,57(8):860-869
Recently, interest in analysis and generation of human and human-like motion has increased in various areas. In robotics, in order to operate a humanoid robot, it is necessary to generate motions that have strictly dynamic consistency. Furthermore, human-like motion for robots will bring advantages such as energy optimization.This paper presents a mechanism to generate two human-like motions, walking and kicking, for a biped robot using a simple model based on observation and analysis of human motion. Our ultimate goal is to establish a design principle of a controller in order to achieve natural human-like motions. The approach presented here rests on the principle that in most biological motor learning scenarios some form of optimization with respect to a physical criterion is taking place. In a similar way, the equations of motion for the humanoid robot systems are formulated in such a way that the resulting optimization problems can be solved reliably and efficiently.The simulation results show that faster and more accurate searching can be achieved to generate an efficient human-like gait. Comparison is made with methods that do not include observation of human gait. The gait has been successfully used to control Robo-Erectus, a soccer-playing humanoid robot, which is one of the foremost leading soccer-playing humanoid robots in the RoboCup Humanoid League. 相似文献
82.
Carl Lederman Anand Joshi Ivo Dinov John Darrell Van Horn Luminita Vese Arthur Toga 《Journal of Mathematical Imaging and Vision》2016,55(2):179-198
We introduce a new volumetric registration technique that effectively combines active surfaces with the finite element method. The method simultaneously aligns multi-label automatic structural segmentation results, which can be obtained by the application of existing segmentation software, to produce an anatomically accurate 3D registration. This registration is obtained by the minimization of a single energy functional. Just like registering raw images, obtaining a 3D registration this way still requires solving a fundamentally ill-posed problem. We explain through academic examples as well as an MRI dataset with manual anatomical labels, which are hidden from the registration method, how the quality of a registration method can be measured and the advantages our approach offers. 相似文献
83.
84.
A compact printed multistubs loaded resonator rectangular monopole antenna design for multiband wireless systems 下载免费PDF全文
In the present article, a compact triple‐band multistubs loaded resonator printed monopole antenna is proposed. The antenna consists of a quarter wavelength two asymmetrical inverted L‐shaped stubs to excite two resonant modes for 3.5/5.5 GHz bands and one integrated horizontally T‐shaped stub with inverted long L‐shaped stub to excite resonant mode for 2.5 GHz band. By loading these stub resonators along y‐axis with distinct gaps, the antenna resonates at three frequencies 2.57/3.52/5.51 GHz covering the desired bands while keeping compact size of 24 × 30 mm2 (0.2 × 0.25 ). The proposed antenna is fabricated on Rogers RT/duroid 5880 substrate with thickness 0.79 mm and its performance experimentally verified. The measured results reveal that the antenna has the impedance bandwidths of about 210 MHz (2.50‐2.71 GHz), 260 MHz (3.37‐3.63 GHz), and 650 MHz (5.20‐5.85 GHz), for 2.5/3.5/5.5 GHz WiMAX and 5.2/5.8 GHz WLAN band systems. The antenna provides omnidirectional radiation patterns and flat antenna gains over the three operating bands. In addition, the design approach and effects of multistubs resonator lengths on the operating bands are also examined and discussed in detail. 相似文献
85.
Tri‐band composite cylindrical dielectric resonator antenna with hybrid mode excitation and cross‐polarization suppression 下载免费PDF全文
This communication investigates composite cylindrical dielectric resonator antenna (CDRA) for various wireless applications. Three important features of proposed antenna design are (i) realization of two different hybrid modes, that is, HEM11δ and HEM12δ mode in CDRA with the help of modified annular ring printed line (work as both magnetic dipole and electric dipole), both the hybrid modes support broadside radiation characteristics (ii) suppression of HEM21δ mode, in order to reduce the cross‐polarization level in H‐plane of other hybrid modes (HEM11δ and HEM12δ mode) by an amount of 8‐10 dB (iii) creation of triple‐band attribute using the concept of composite antenna. The proposed antenna design has been fabricated and practically tested. Simulated outcomes show good agreement with measured outcomes. It works in three frequency bands, that is, 2.25‐2.79 GHz, 3.1‐4.0 GHz, and 5.05‐5.6 GHz. The designed antenna structure is appropriate for WLAN and WiMAX applications. 相似文献
86.
Towards the development of a virtual environment-based training system for mechanical assembly operations 总被引:2,自引:1,他引:1
John E. Brough Maxim Schwartz Satyandra K. Gupta Davinder K. Anand Robert Kavetsky Ralph Pettersen 《Virtual Reality》2007,11(4):189-206
In this paper, we discuss the development of Virtual Training Studio (VTS), a virtual environment-based training system that
allows training supervisors to create training instructions and allows trainees to learn assembly operations in a virtual
environment. Our system is mainly focused on the cognitive side of training so that trainees can learn to recognize parts,
remember assembly sequences, and correctly orient the parts during assembly operations. Our system enables users to train
using the following three training modes: (1) Interactive Simulation, (2) 3D Animation, and (3) Video. Implementing these
training modes required us to develop several new system features. This paper presents an overview of the VTS system and describes
a few main features of the system. We also report user test results that show how people train using our system. The user
test results indicate that the system is able to support a wide variety of training preferences and works well to support
training for assembly operations.
相似文献
Satyandra K. GuptaEmail: |
87.
Summary An overview ofvariational inequality andvariational equality formulations for frictionless contact and frictional contact problems is provided. The aim is to discuss the state-of-the-art
in these two formulations and clearly point out their advantages and disadvantages in terms of mathematical completeness and
practicality. Various terms required to describe the contact configuration are defined.Unilateral contact law and classical Coulomb’s friction law are given.Elastostatic frictional contact boundary value problem is defined. General two-dimensional frictionless and frictional contact formulations for elastostatic
problems are investigated. An example problem of a two bar truss-rigid wall frictionless contact system is formulated as an
optimization problem based on the variational inequality approach. The problem is solved in a closed form using the Karush-Kuhn-Tucker
(KKT) optimality conditions. The example problem is also formulated as a frictional contact system. It is solved in the closed
form using a new two-phase analytical procedure. The procedure avoids use of the incremental/iterative techniques and user
defined parameters required in a typical implementation based on the variational equality formulation. Numerical solutions
for the frictionless and frictional contact problems are compared with the results obtained by using a general-purpose finite
element program ANSYS (that uses variational equality formulation). ANSYS results match reasonably well with the solutions
of KKT optimality conditions for the frictionless contact problem and the two-phase procedure for the frictional contact problem.
The validity of the analytical formulation for frictional contact problems (with one contacting node) is verified. Thevariational equality formulation for frictionless and frictional, contact problems is also studied in detail. The incremental/iterative Newton-Raphson
scheme incorporating the penalty approach is utilized. Studies are conducted to provide insights for the numerical solution
techniques. Based on the present study it is concluded that alternate formulations and computational procedures need to be
developed for analysis of frictional contact problems. 相似文献
88.
89.
Concept-based near-duplicate video clip detection for novelty re-ranking of web video search results
State-of-the-art near-duplicate video clip (NDVC) detection for novelty re-ranking uses non-semantic low-level features (color/texture) to detect and eliminate “content-based NDVC” and increases content level novelty in the top results. However, humans may perceive a video as near duplicate from a semantic perspective as well. In this paper, we propose concept-based near-duplicate video clip (CBNDVC) detection technique for novelty re-ranking. We identify “semantic NDVC”, making use of the semantic features (events/concepts) and re-rank the top results to increase the content as well as semantic novelty. Videos are represented as a multivariate time series of confidence values of relevant concepts and thereafter discovery of CBNDVC clusters is achieved by conceptual clustering. Obtained results show higher precision and recall from the user’s perspective. 相似文献
90.
In human designer usage, symbols have a rich semantics, grounded on experience, which permits flexible usage — e.g. design ideation is improved by meanings triggered by contrastive words. In computational usage however, symbols are syntactic tokens whose semantics is mostly left to the implementation, resulting in brittle failures in many knowledge-based systems. Here we ask if one may define symbols in computational design as {label,meaning} pairs, as opposed to merely the label. We consider three questions that must be answered to bootstrap a symbol learning process: (a) which concepts are most relevant in a given domain, (b) how to define the semantics of such symbols, and (c) how to learn labels for these so as to form a grounded symbol. We propose that relevant symbols may be discovered by learning patterns of functional viability. The stable patterns are information-conserving codes, also called chunks in cognitive science, which relate to the process of acquiring expertise in humans. Regions of a design space that contain functionally superior designs can be mapped to a lower-dimensional manifold; the inter-relations of the design variables discovered thus constitute the chunks. Using these as the initial semantics for symbols, we show how the system can acquire labels for them by communicating with human designers. We demonstrate the first steps in this process in our baby designer approach, by learning two early grounded symbols, tight and loose. 相似文献