9173348
Particle Swarm Optimization for Simultaneous Optimization of Design and Machining Tolerances
Tolerance assignment is an important issue in product design and manufacturing. However, this problem is commonly formulated as nonlinear, multi-variable and high constrained model. Most of the heuristics for this problem are based on penalty function strategy which unfortunately suffers from inherent drawbacks. To overcome these drawbacks, this paper presented a new powerful tool-Particle Swarm Optimization algorithm (PSO) and meanwhile proposed a sophisticated constraints handling scheme suitable for the optimization mechanism of PSO. An example involving simultaneously assigning both design and machining tolerances based on optimum total machining cost is employed to demonstrate the efficiency and effectiveness of the proposed approach. The experimental result based on the comparison between PSO and GA show that the new PSO model is a powerful tool.
2612705
Credit Scoring Model Based on Neural Network with Particle Swarm Optimization
Credit scoring has gained more and more attentions both in academic world and the business community today. Many modeling techniques have been developed to tackle the credit scoring tasks. This paper presents a Structure-tuning Particle Swarm Optimization (SPSO) approach for training feed-forward neural networks (NNs). The algorithm is successfully applied to a real credit problem. By simultaneously tuning the structure and connection weights of NNs, the proposed algorithm generates optimized NNs with problem-matched information processing capacity and it also eliminates some ill effects introduced by redundant input features and the corresponding redundant structure. Compared with BP and GA, SPSO can improve the pattern classification accuracy of NNs while speeding up the convergence of training process.
33132446
Fuzzy control rules extraction from perception-based information using computing with words
In this paper, a novel approach to extract fuzzy control rules from perception-based information using computing with words (CW) is firstly presented. The approach is based on applying fuzzy numbers and their arithmetic operations. The fuzzy Lyapunov synthesis, which gives a linguistic description on the plant and the control objective, is used to design a stable fuzzy controller. Secondly, that the traditional fuzzy-control rules can be derived systematically, rather than heuristically, and their stability can be guaranteed is demonstrated. Moreover, by introducing fuzzy numbers and their arithmetic operations, the "words" represented by fuzzy numbers could be efficiently manipulated for fuzzy controller design. The performance and applicability of the proposed method are illustrated through the practical implementation of fuzzy control of a pole-balancing vehicle.
15559973
Robo-Erectus: a low-cost autonomous humanoid soccer robot
The humanoid soccer robot league is a new international initiative to foster robotics and AI technologies using soccer games [1]. This paper provides a brief description of a low-cost autonomous humanoid soccer robot called Robo-Erectus (RE), which has been developed in the Center for Advanced Robotics and Intelligent Control (ARICC) at Singapore Polytechnic since 2001. To develop a low-cost humanoid platform which is affordable for many researchers, our RE humanoid robots have been intentionally designed using low-torque servo motors and low-precision mechanical structures so that the cost can be significantly reduced. We demonstrate that the humanoid biped locomotion can be formulated as an optimization problem with consideration of some constraints. In the frame of gait synthesis tied with constraint functions, computational learning methods, e.g. fuzzy reinforcement learning (FRL), can be incorporated to further improve the gait [2]. The proposed control and learning methods have been successfully tested on our RE humanoid soccer robots which finished second in the RoboCup 2002 Humanoid Walk competition and first in the RoboCup 2003 Humanoid Free Performance competition.
12769414
Robot learning with GA-based fuzzy reinforcement learning agents
Abstract How to learn from both expert knowledge and measurement-based information for a robot to acquire perception and motor skills is a challenging research topic in the field of autonomous robotic systems. For this reason, a general GA (genetic algorithm)-based fuzzy reinforcement learning (GAFRL) agent is proposed in this paper. We first characterize the robot learning problem and point out some major issues that need to be addressed in conjunction with reinforcement learning. Based on a neural fuzzy network architecture of the GAFRL agent, we then discuss how different kinds of expert knowledge and measurement-based information can be incorporated in the GAFRL agent so as to accelerate its learning. By making use of the global optimization capability of GAs, the GAFRL can solve the local minima problem in traditional actor-critic reinforcement learning. On the other hand, with the prediction capability of the critic network, GAs can evaluate the candidate solutions regularly even during the periods without external feedback from the environment. This can guide GAs to perform a more effective global search. Finally, different types of GAFRL agents are constructed and verified using the simulation model of a physical biped robot.
1882154
Providing Quality of Service in IEEE 802.11 WLAN
This paper aims to provide quality of service (QoS) for IEEE 802.11 wireless local area network (WLAN). Specifically, we develop a new scheduling algorithm in link layer to support multimedia services with guaranteed QoS in WLAN. The proposed scheduling algorithm makes use of the idle system time to reduce average packet loss of real-time (RT) variable-bit-rate (VBR) services, while satisfying required transmission delay and bandwidth requirements of all RT services. Detailed analysis is given by taking into account several key statistical factors, such as service traffic model, the ratio between the polling period and the contention period (CP), burst generation probabilities. Performance is evaluated through OPNET simulation. Simulation results demonstrate that our proposed joint scheme is effective in terms of both system resource utilization and QoS provisioning
9275481
RoboCup 2004 Competitions and Symposium: A Small Kick for Robots, a Giant Score for Science
RoboCup is an international initiative with the main goals of fostering research and education in artificial intelligence and robotics, as well as of promoting science and technology to world citizens. The idea behind RoboCup is to provide a standard problem for which a wide range of technologies can be integrated and examined, as well as being used for project-oriented education, and to organize annual events open to the general public, at which different solutions to the problem are compared. The eighth annual RoboCup -- RoboCup 2004 -- was held in Lisbon, Portugal, from 27 June to 5 July. In this article, a general description of RoboCup 2004 is presented, including summaries concerning teams, participants, distribution into leagues, main research advances, as well as detailed descriptions for each league.