27048178
Mechanism and control of mobile pipeline maintenance robot with lazy tongs mechanism
A new type of mobile pipeline maintenance robot has been designed to clarify the feasibility of lazy tongs mechanism for adaptation to various size pipelines. The robot basically consists of three modules with two joints between modules and can move straight and spirally along the surface of pipeline. The robot can change its arm length in order to move on the pipeline of various size from 25 A to 100 A, and pass over obstacles such as reducer, diffuser, flange and other plant equipment. The control of the robot is so complicated that the modified dual control mode is introduced using the coordinate transformation matrix. By calculating the position and attitude of the robot under the control mode, the manoeuvrability of passing over a reducer is shown with experimental results.
30858440
Vision based navigation system for autonomous mobile robot with global matching
We have previously developed a navigation system for an autonomous mobile robot. It can find the landmarks on the ceiling for navigation. However, when the robot fails to recognize a landmark, the robot can not calculate the self-position. So, the robot has to prepare for the behavior of error recovery. But an error that is not able to recover may occur. In such a case, the robot needs to relocate the self-position. In this paper, we define global matching as the behavior that is able to relocate the self-position and propose to use this module for the error recovery in HALAS (hierarchical adaptive and learning architecture system) that we have proposed as a hierarchical system.
14481721
Dynamic Resource Allocation Based on On-the-Fly Reservation
Resource reservation is a vital issue for grid-enabled programs to execute smoothly. Instead of using metascheduling solutions to request grid resources statically, we are developing a tiny C++ library to reserve on-demand computing resources based on Globus Toolkit, local schedulers such as Maui, and SQLite database. The interface class is named CReservation in the library. At the time of preparing this paper, the only implementation available is for Maui scheduler. With such implementation classes, one can request, release, and monitor reservations of computing resources dynamically. To verify the simplicity, usability, and stability of current library, we have performed an in-depth case study with a grid enabled hybrid MD/QM (Molecular Dynamics/Quantum Mechanical) multi-scale simulation program. Our test shows that this library provides an easy and effective approach to manage resource reservations from within grid-enabled applications.
13964619
Parallelization of Saprse Cholesky Factorization on an SMP Cluster
In this paper, we present parallel implementations of the sparse Cholesky factorization kernel in the SPLASH-2 programs to evaluate performance of a Pentium Pro based SMP cluster. Solaris threads and remote memory operations are utilized for intranode parallelism and internode communications, respectively. Sparse Cholesky factorization is a typical irregular application with a high communication to computation ratio and no global synchronization between steps. We efficiently parallelized using asynchronous message handling instead of lock-based mutual exclusion between nodes, because synchronization between nodes reduces the performance significantly. We also found that the mapping of processes to processors on an SMP cluster affects the performance especially when the communication latency can not be hidden.
10817469
COMPaS: A Pentium Pro PC-based SMP Cluster and Its Experience
We have built an eight node SMP cluster called COMPaS (Cluster Of Multi-Processor Systems), each node of which is a quadprocessor Pentium Pro PC. We have designed and implemented a remote memory based user-level communication layer which provides lowover-head and high bandwidth using Myrinet. We designed a hybrid programming model in order to take advantage of locality in each SMP node. Intra-node computations utilize a multi-threaded programming style (Solaris threads) and inter-node programming is based on message passing and remote memory operations. In this paper we report on this hybrid shared memory/distributed memory programming on COMPaS and its preliminary evaluation. The performance of COMPaS is affected by data size and access patterns, and the proportion of inter-node communication. If the data size is small enough to all fit on the cache, parallel efficiency exceeds 1.0 using the hybrid programming model on COMPaS. But the performance is limited by the low memory bus bandwidth of PC-based SMP nodes for some memory intensive workloads.