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1.
The process of protein crystallization is explained using the theory of robotics, particularly path planning of mobile robots. Path planning is a procedure which specifies motion trajectories of multiple mobile robots to form a robotic
team with a desired pattern. Since protein crystals consist of a large number of protein molecules which come together to
form a 3D lattice of uniform structure, it is hypothesized that each protein behaves like a mobile robot and takes adequate
path to form a robotic team (crystal). Based on this hypothesis, it is shown that trajectories of the proteins should be simple and local, which generates three rules of motion for the protein robots, i.e., (a) each protein searches for its nearest neighbor,
(b) each protein takes the shortest path to approach the nearest neighbor, and (c) multiple proteins may form a sub-team of
proteins. It is then proven mathematically that the planned path according to the three rules is stable and able to crystallize
the proteins. Interaction forces at the molecular level are analyzed to show that the simple and local motion of the proteins
is physically warranted. Computer simulation and experimental results are presented to validate the new theory.
相似文献
Yuan F. ZhengEmail: |
2.
为描述机器人队列的运动过程,从相对位姿的角度定义了多移动机器人的队形模型.在传统leader-following队形控制的基础上,引入切换控制思想,每对领路机器人与跟随机器人之间设计3个控制器,对应跟随机器人中轴线上两参考点分别设计两个运动子控制器,控制领路机器人与跟随机器人之间的相对位姿;切换控制器根据系统处于平衡状态时,跟随机器人线速度的符号切换运动控制器,从而保证队列收敛到目标队形.仿真实验结果表明,机器人队列表现出良好的整体一致性,队列运动更加平稳. 相似文献
3.
A sensor-based motion control system was designed to autonomously drive vehicles free of collisions in unknown, troublesome and dynamic scenarios. The system was developed based on a hybrid architecture with three layers (modeling, planning and reaction). The interaction of the modules was based on a synchronous planner–reactor configuration where the planner computes tactical information to direct the reactivity. Our system differs from previous ones in terms of the choice of the techniques implemented in the modules and in the integration architecture. It can achieve robust and reliable navigation in difficult scenarios that are troublesome for many existing methods. Experiments carried out in these scenarios with a real vehicle confirm the effectiveness of this technique. 相似文献
4.
This paper presents an approach for decentralized real-time motion planning for multiple mobile robots operating in a common 2-dimensional environment with unknown stationary obstacles. In our model, a robot can see (sense) the surrounding objects. It knows its current and its target's position, is able to distinguish a robot from an obstacle, and can assess the instantaneous motion of another robot. Other than this, a robot has no knowledge about the scene or of the paths and objectives of other robots. There is no mutual communication among the robots; no constraints are imposed on the paths or shapes of robots and obstacles. Each robot plans its path toward its target dynamically, based on its current position and the sensory feedback; only the translation component is considered for the planning purposes. With this model, it is clear that no provable motion planning strategy can be designed (a simple example with a dead-lock is discussed); this naturally points to heuristic algorithms. The suggested strategy is based on maze-searching techniques. Computer simulation results are provided that demonstrate good performance and a remarkable robustness of the algorithm (meaning by this a virtual impossibility to create a dead-lock in a random scene). 相似文献
5.
A Logic for Characterizing Multiple Bounded Agents 总被引:1,自引:1,他引:0
We describe a meta-logic for characterizing the evolving internal reasoning of various families of agents. We view the reasoning of agents as ongoing processes rather than as fixed sets of conclusions. Our approach utilizes a strongly sorted calculus, distinguishing the application language, time, and various syntactic sorts. We have established soundness and completeness results corresponding to various families of agents. This allows for useful and intuitively natural characterizations of such agents' reasoning abilities. We discuss and contrast consistency issues as in the work of Montague and Thomason. We also show how to represent the concept of focus of attention in this framework. 相似文献
6.
New and envisioned technological means and abilities for exerting command and control have increased the interest of man-machine research in a military context. Although there are many current proposals for how new command and control systems should be designed, many of the proposed properties that are considered advantageous have never been tested or could even be impossible to test in real-world situations. In spite of that, proposed design solutions are generally held valid in many Western countries where developments of major command and control system projects are in progress. An important question is how microworlds can be used for research on team decision-making. The use of microworlds gives us the possibility to create controlled settings and the opportunity to use advanced monitoring tools to study the subjects. Our studies indicate that the microworld concept, even though the simulation is fairly simple, reflects some of the crucial aspects of team-work in dynamic settings. The article presents results from a study in command and control using the C3Fire microworld (). Results and methodological issues are discussed.
相似文献
Rego GranlundEmail: |
7.
This paper discusses experiences from monitoring command and control in research with the C3Fire microworld environment. The experiences are based on three microworld studies where a total of 192 persons participated as students. 132 of these students were computer-literate undergraduate students and 60 were professional military officers. During the three studies, different monitoring strategies were used to meet the goals of the studies. The main monitoring goal has been to detect different aspects of the teamwork performed by the subjects in the experiments. The focus of the monitoring goal was: 1) to monitor the effectiveness of the students' work and the communication patterns between the students in a command and control situation 2) to monitor the students' situation awareness (SA) when the students were using a graphical- or a textual-based information system 3) to monitor the students' work procedures and the possibilities of automatically analysing textual information sent by e-mail. 相似文献
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全自动供丝设备是一种用于卷烟生产的新型供丝装置,它的核心是计算机控制系统。本文将讨论控制系统的功能要求以及根据这些功能要求所取的硬件及软件结构;同时,还重点讨论了有关采用高级语言编制中断服务程序所遇到的问题及解决办法;特别地,文中对如何在单用户单任务DOS操作系统环境下实现实时多任务功能作了较深入的探讨,井提出了一些经实践证明确实是行之有效的方法。 相似文献
10.
This paper considers a system of autonomous mobile robots that can move freely in a two-dimensional plane, and where a number of them can fail by crashing. The crash of a robot can be either permanent or temporary, that is, after its crash the robot either executes no action or it recovers from its failure. These robots repeatedly go through a succession of activation cycles during which they observe the environment, compute a destination and move. In particular, we assume weak robots, in the sense that robots cannot communicate explicitly between each other. Also, they cannot remember their past computations (i.e., they are oblivious). Finally, robots do not agree on a common coordinate system.In this paper, we address the fault-tolerant flocking problem under the crash-recovery model. That is, starting from any initial configuration, a group of non-faulty robots are required to form a desired pattern, and move together while following a robot leader moving on some trajectory, and keeping such a pattern in movement. Specifically, we propose a fault-tolerant flocking algorithm in the semi-synchronous model that allows correct robots to dynamically form a regular polygon in finite time, and maintain it in movement infinitely often. Our algorithm relies on the existence of two devices, namely an eventually perfect failure detector device to ensure failure detection, and also an eventual leader device to handle leader election. The algorithm tolerates permanent crash failures, and also crash-recovery failures of robots due to its oblivious feature. The proposed algorithm ensures the necessary restrictions on the movement of robots in order to avoid collisions between them. In addition, it is robust with respect to changes in the environment. 相似文献
11.
Formation shape control based on bearing rigidity 总被引:2,自引:0,他引:2
Tolga Eren 《International journal of control》2013,86(9):1361-1379
Distance measurements are not the only geometric quantities that can be used for multi-agent formation shape control. Bearing measurements can be used in conjunction with distances. This article employs bearing rigidity for mobile formations, which was developed for robot and sensor network localisation, so that bearings can be used for shape control in mobile formations. The first part of this article examines graph theoretical models for formation network analysis and control law design that are needed to maintain the shape of a formation in two-dimensional space, while the formation moves as a cohesive whole. Bearing-based shape control for a formation of mobile agents involves the design of distributed control laws that ensure the formation moves, so that bearing constraints maintain some desired values. The second part of this article focuses on the design of a distributed control scheme for nonholonomic agents to solve the bearing-based formation shape control problem. In particular, a control law using feedback linearisation is proposed based on shape variables. We simulate the shape control behaviour on differential drive agents for an exemplary bearing rigid formation using the results obtained in the first and second parts of this article. 相似文献
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Katsuhiro Moizumi George Cybenko 《Mathematics of Control, Signals, and Systems (MCSS)》2001,14(3):213-232
This paper considers a sequencing problem which arises naturally in the scheduling of software agents. We are given n sites at which a certain task might be successfully performed. The probability of success is p
i at the ith site and these probabilities are independent. Visiting site i and trying the task there requires time (or some other cost metric) t
i whether successful or not. Latencies between sites i and j are l
ij, that is, the travel time between those two sites. Should the task be successfully completed at a site then any remaining
sites do not need to be visited. The Traveling Agent Problem is to find the sequence which minimizes the expected time to complete the task. The general formulation of this problem is
NP-Complete. However, if the latencies are constant we show that the problem can be solved in polynomial time by sorting the
ratios t
i/p
i according to increasing value and visiting the sites in that order. This result then leads to an efficient algorithm when
groups of sites form subnets in which latencies within a subnet are constant but can vary across subnets. We also study the case when there are deadlines
for solving the problem in which case the goal is to maximize probability of success subject to satisfying the deadlines.
Applications to mobile and intelligent agents are described.
Date received: February 10, 1998. Date revised: November 16, 1999. 相似文献
14.
A novel time‐varying adaptive controller at the torque level is proposed to simultaneously solve the stabilization and the tracking problem of unicycle mobile robots with unknown dynamic parameters. The idea underlying the controller is intuitively simple: rather than switching between two different types of controllers according to the a priori knowledge of the reference velocities being persistently exciting or not, a new time‐varying signal is introduced to make the single controller capable of adaptively, smoothly, and gradually converting between stabilizer and tracker depending on the instantaneous and past information of the reference velocities. Our control development is based on Lyapunov's direct method and the backstepping technique. Adaptive control techniques are used to deal with parametric uncertainties. The outstanding feature of our controller is computationally simple due to its full use of the existing results on stabilization and tracking control for unicycle robots. With our approach, robots can globally follow a large class of paths including a straight line, a circle, a path approaching a set‐point, or just a set‐point using a single controller. Simulation results for a unicycle‐type mobile robot are provided to illustrate the effectiveness of the proposed controller. 相似文献
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Brand marketing for creating brand value based on a MCDM model combining DEMATEL with ANP and VIKOR methods 总被引:1,自引:0,他引:1
Yung-Lan Wang 《Expert systems with applications》2012,39(5):5600-5615
When consumers purchase products, they will consider the brand first, because it indirectly leads consumers to associate the products with the quality, functions, and the design. Based on the smiling curve, it showed enhancing the marketing or R&D will create value-added to the products or brands. Thus, this study intended to use brand marketing to create brand value. However, there are many criteria among the strategies, and they are interrelated. Therefore, this study utilized the MCDM model combining DEMATEL with ANP and VIKOR methods to clarify the interrelated relationships of brand marketing and find the problems or gaps; then, evaluated the situation to reduce the gaps in order to achieve the aspired levels and rank the priorities in brand marketing strategies, we also evaluated the customer’s satisfaction of brand marketing by three electronic manufacturing companies in Taiwan. As the empirical results, value pricing is the most important factor, followed by consumer’s price perception and perceived quality while showed the highest satisfaction of brand marketing was in F2 company. The results of this paper will provide the enterprises with a reference for planning brand marketing. 相似文献
17.
Mario Prats Ester Martínez Pedro J. Sanz Angel P. del Pobil 《Intelligent Service Robotics》2008,1(4):321-335
This paper describes the UJI librarian robot, a mobile manipulator that is able to autonomously locate a book in an ordinary
library, and grasp it from a bookshelf, by using eye-in-hand stereo vision and force sensing. The robot is only provided with
the book code, a library map and some knowledge about its logical structure and takes advantage of the spatio-temporal constraints
and regularities of the environment by applying disparate techniques such as stereo vision, visual tracking, probabilistic
matching, motion estimation, multisensor-based grasping, visual servoing and hybrid control, in such a way that it exhibits
a robust and dependable performance. The system has been tested, and experimental results show how it is able to robustly
locate and grasp a book in a reasonable time without human intervention. 相似文献
18.
多移动代理协作的多重数字签名在移动代理技术领域,特别是电子商务领域,有着广阔的应用前景。本文鉴于移动代理的安全问题,针对“主从代理协作”这一新兴概念,提出了一种基于ElGamal密码系统和ElGamal密码系统在DSS(数字签名标准)中变换形式的多重数字签名方案,并通过一个具体的商务案例分析其安全性和有效性,得出了若干结论。 相似文献
19.
本文以一个典型实时应用为背景,从时间方面、可靠性方面、安全方面等系统分析它的QoS需求,从而定义了多雏QoS参数,在已有QoS结构的基础上建立了实时系统的QoS层次模型。 相似文献