15051068
Study on Epipolar Geometry Restoration of Parallel Binocular Vision
The epipolar geometry restoration offline and online for the parallel binocular vision system were discussed in this paper. For the former, a method that uses a common calibration board to realize automatic and accurate matching of the image corner pairs was developed; for the latter, a connotative constraint was proved by geometry theory and the corresponding cross-correlation sparse matching algorithm was introduced. The constraint was that for any space point projected into two images, the horizontal coordinate in the left image of this point is bigger than that in the right image. Standard and real images experiments were made for each kind of problem and the results show that the algorithms for each problem were valid.
21075507
BP Networks Based Trajectory Planning and Inverse Kinematics of a Reconfigurable Mars Rover
The inverse kinematics of series manipulators presents an inherent complexity due to their various structures and kinematics constraints. To a novel reconfigurable Mars rover's arm, the inverse kinematics had been solved by numerical method combined with space geometry relations, but the complex calculating process can not be utilized in real-time control. In this paper, some actions in common use are programmed in the child rover, and the BP neural network was used to solve the inverse kinematics and trajectory planning. To a desired trajectory, some solutions by direct kinematics algorithms and geometry relations corresponding to the trajectory were used as the BP network's training data set, and the non-linear mapping from joint-variable space to operation-variable space was obtained with iterative training and learning method. The results show the output of training is consistent with the desired path, and the obtained reference trajectory is smooth.
152660
Gaits-transferable CPG controller for a snake-like robot
With slim and legless body, particular ball articulation, and rhythmic locomotion, a nature snake adapted itself to many terrains under the control of a neuron system. Based on analyzing the locomotion mechanism, the main functional features of the motor system in snakes are specified in detail. Furthermore, a bidirectional cyclic inhibitory (BCI) CPG model is applied for the first time to imitate the pattern generation for the locomotion control of the snake-like robot, and its characteristics are discussed, particularly for the generation of three kinds of rhythmic locomotion. Moreover, we introduce the neuron network organized by the BCI-CPGs connected in line with unilateral excitation to switch automatically locomotion pattern of a snake-like robot under different commands from the higher level control neuron and present a necessary condition for the CPG neuron network to sustain a rhythmic output. The validity for the generation of different kinds of rhythmic locomotion modes by the CPG network are verified by the dynamic simulations and experiments. This research provided a new method to model the generation mechanism of the rhythmic pattern of the snake.
206600042
Multiagent Reinforcement Learning for a Planetary Exploration Multirobot System
In a planetary rover system called “SMC rover”, the motion coordination between robots is a key problem to be solved. Multiagent reinforcement learning methods for multirobot coordination strategy learning are investigated. A reinforcement learning based coordination mechanism is proposed for the exploration system. Four-robot climbing a slope is studied in detail as an instance. The actions of the robots are divided into two layers and realized respectively, which simplified the complexity of the climbing task. A Q-Learning based multirobot coordination strategy mechanism is proposed for the climbing mission. An OpenGL 3D simulation platform is used to verify the strategy and the learning results.
14083445
Network-based reconfiguration routes for a self-reconfigurable robot
This paper presents a network-based analysis approach for the reconfiguration problem of a self-reconfigurable robot. The self-reconfigurable modular robot named “AMOEBA-I” has nine kinds of non-isomorphic configurations that consist of a configuration network. Each configuration of the robot is defined to be a node in the weighted and directed configuration network. The transformation from one configuration to another is represented by a directed path with nonnegative weight. Graph theory is applied in the reconfiguration analysis, where reconfiguration route, reconfigurable matrix and route matrix are defined according to the topological information of these configurations. Algorithms in graph theory have been used in enumerating the available reconfiguration routes and deciding the best reconfiguration route. Numerical analysis and experimental simulation results prove the validity of the approach proposed in this paper. And it is potentially suitable for other self-reconfigurable robots’ configuration control and reconfiguration planning.
206544153
Analysis of creeping locomotion of a snake robot on a slope
Biological snakes' diverse locomotion modes and physiology make them supremely adapted for environment. To realize these snakes' noticeable features, we have developed a snake-like robot that has no any forward direction driving force. To enlarge the environment-adaptable ability of our robot, in this study we discuss the creeping locomotion of our snake-like robot on a slope. A computer simulator is presented for analysis of the creeping locomotion of our snake-like robot on a slope, and the environment-adaptable body shape for the creeping locomotion of the snake-like robot on slope is also derived through this simulator.
17604686
Enhanced high-performance distributed coordination function for IEEE 802.11 multi-rate LANs
To compensate for the effects of fading in wireless channels, IEEE 802.11 systems utilize a rate-adaptation mechanism to accomplish a multi-rate capability. However, the IEEE 802.11 distributed coordination function results in a fundamental performance anomaly in multi-rate networks; namely, when stations with different transmission rates collide, the throughput performance of the high-rate station is significantly degraded by the relatively longer channel occupancy time of the low-rate station. This study resolves this problem through the use of an enhanced high-performance distributed coordination function (EHDCF) protocol. While most existing solutions to the multi-rate performance anomaly problem have the form of simple contention-based protocols, EHDCF has two modes, namely a contending mode and an active mode. In the proposed protocol, new stations joining the network are assigned a contending mode, but switch to an active node (and are therefore permitted to transmit data packets) as soon as they have gained access to the channel. Having transmitted a data packet, the active node then selects the next transmission station in accordance with a probability-based rule designed such that the high-rate stations within the network receive a greater number of transmission opportunities than the low-rate stations. The simulation results show that the EHDCF protocol not only yields a significant improvement in the network throughput but also guarantees the temporal fairness of all the stations. Copyright q 2009 John Wiley & Sons, Ltd.
3451766
Attack LSB Matching Steganography by Counting Alteration Rate of the Number of Neighbourhood Gray Levels
In this paper, we propose a new method for attacking the LSB (least significant bit) matching based steganography. Different from the LSB substitution, the least two or more significant bit-planes of the cover image would be changed during the embedding in LSB matching steganography and thus the pairs of values do not exist in stego image. In our proposed method, we get an image by combining the least two significant bit-planes and divide it into 3x3 overlapped subimages. The subimages are grouped into four types, i.e. T 1,T 2, T 3 and T 4 according to the count of gray levels. Via embedding a random sequence by LSB matching and then computing the alteration rate of the number of elements in T 1, we find that normally the alteration rate is higher in cover image than in the corresponding stego image. This new finding is used as the discrimination rule in our method. Experimental results demonstrate that the proposed algorithm is efficient to detect the LSB matching stegonagraphy on uncompressed gray scale images.
14518520
Design and Implementation of an Automated Microscope Stage
Optical microscopes remain keen instruments for scientific research nowadays. Widely used in hospitals and laboratories, such equipment helps people deal with various kinds of tasks, most of which, however, are both onerous and tedious; therefore, operations on these manually executed instruments are lengthily and subject to human errors. To alleviate this problem, we equip an optical microscope with two stepper motors and implement the automatic control of the microscope stage. This paper introduces the control system architecture and discusses in detail the development of the communication subsystem and the stepper motor controllers. Test results with a practical application are also provided to illustrate the performance of this system.
27275974
Distributed Spatial Catalog Service on the CORBA Object Bus
Spatial catalog service is a necessary component for distributed geographic information. Spatial catalog services provide the capabilities for organizing and managing spatial metadata. Catalog services simplify the process of data discovery in a large spatial database, facilitate data transfer, and help data fusion.This paper presents a software architecture for spatial catalog services. We first discuss the general concept of spatial catalog facilities and the logical model of spatial catalog services. We then introduce the distributed object-oriented model for spatial catalog services based on the industrial standard Common Object Request Broker Architecture (CORBA). The core components of spatial catalog services, catalog and catalog registry, are described in detail with the CORBA Interface Definition Language (IDL). Examples are given to illustrate the structure of the catalog component and its relations with other service components in a distributed GIS. The model provides a common interface to spatial catalogs and related data no matter how catalogs are defined, what formats they use, and where they are located. It provides crucial services in a distributed Geographic Information System.
38250707
Minimizing Spatial Deformation Method for Online Signature Matching
Elastic matching is an important algorithm for online signature verification. Most of elastic matching algorithms are based on dynamic time warping(DTW). In this paper, we propose a new points matching algorithm for online signature verification. After resampling a signature with equidistant spacing, we describe the resampling point by its (3+1) demesional((3+1)D) information: 3D spatial information (x-axis, y-axis, time) and a feature vector. A soft-assign matrix and two special restrictions are introduced for recording the correspondence between two signatures. With a deterministic annealing framework, the mapping between two sets of (3+1)D signature points is achieved by minimizing the warping energy of the thin-plate spline(TPS). Experimental results demonstrate that the proposed algorithm outperforms the DTW-based matching algorithms.