24,494 research outputs found
Lemon: an MPI parallel I/O library for data encapsulation using LIME
We introduce Lemon, an MPI parallel I/O library that is intended to allow for
efficient parallel I/O of both binary and metadata on massively parallel
architectures. Motivated by the demands of the Lattice Quantum Chromodynamics
community, the data is stored in the SciDAC Lattice QCD Interchange Message
Encapsulation format. This format allows for storing large blocks of binary
data and corresponding metadata in the same file. Even if designed for LQCD
needs, this format might be useful for any application with this type of data
profile. The design, implementation and application of Lemon are described. We
conclude with presenting the excellent scaling properties of Lemon on state of
the art high performance computers
Online Collaborative Editor
“Online collaborative editor” is a node.js based browser application that provides real time collaborative editing of files and improves pair programming. Current real time editors fail to provide simultaneous viewing and editing of files within the server and results in a complex version controlling system. Such systems are also vulnerable to deadlocks and race conditions. This project provides a platform for real time collaborative editors, which can support simultaneous editing and viewing of files and handle concurrency problems by using locking mechanism. The experiment results showed that node.js platform provides good performance for collaborative editing
Program Transformations for Asynchronous and Batched Query Submission
The performance of database/Web-service backed applications can be
significantly improved by asynchronous submission of queries/requests well
ahead of the point where the results are needed, so that results are likely to
have been fetched already when they are actually needed. However, manually
writing applications to exploit asynchronous query submission is tedious and
error-prone. In this paper we address the issue of automatically transforming a
program written assuming synchronous query submission, to one that exploits
asynchronous query submission. Our program transformation method is based on
data flow analysis and is framed as a set of transformation rules. Our rules
can handle query executions within loops, unlike some of the earlier work in
this area. We also present a novel approach that, at runtime, can combine
multiple asynchronous requests into batches, thereby achieving the benefits of
batching in addition to that of asynchronous submission. We have built a tool
that implements our transformation techniques on Java programs that use JDBC
calls; our tool can be extended to handle Web service calls. We have carried
out a detailed experimental study on several real-life applications, which
shows the effectiveness of the proposed rewrite techniques, both in terms of
their applicability and the performance gains achieved.Comment: 14 page
The driver concept for the DLR Lightweight Robot III
In this paper we present the synchronization and
driver architecture of the DLR LWR-III, which supplies an easy
to use interface for applications. For our purpose we abstracted
the robot hardware entirely from the control algorithms using
the common device driver concept of modern operating systems.
The software architecture is split into two modular parts. On
the one side, there are device drivers that communicate with the
hardware components. On the other side, there are realtime ap-
plications realized as Simulink Models, which provide advanced
control algorithms. This ensures a clean separation between the
two modules and provides a communication over a common
and approved interface. Furthermore we investigated how we
can ensure synchronization to the hardware over the device
driver interfaces and how we can ensure that it meets hard
realtime requirements. The main result of this paper is to realize
a synchronization between LWR-III hardware and Simulink
control applications while targeting small latencies with respect
to hard realtime requirements. The design is implemented and
verified on WindRiverTM VxWorksTM
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