128,168 research outputs found
Distributed Learning System Design: A New Approach and an Agenda for Future Research
This article presents a theoretical framework designed to guide distributed learning design, with the goal of enhancing the effectiveness of distributed learning systems. The authors begin with a review of the extant research on distributed learning design, and themes embedded in this literature are extracted and discussed to identify critical gaps that should be addressed by future work in this area. A conceptual framework that integrates instructional objectives, targeted competencies, instructional design considerations, and technological features is then developed to address the most pressing gaps in current research and practice. The rationale and logic underlying this framework is explicated. The framework is designed to help guide trainers and instructional designers through critical stages of the distributed learning system design process. In addition, it is intended to help researchers identify critical issues that should serve as the focus of future research efforts. Recommendations and future research directions are presented and discussed
PlinyCompute: A Platform for High-Performance, Distributed, Data-Intensive Tool Development
This paper describes PlinyCompute, a system for development of
high-performance, data-intensive, distributed computing tools and libraries. In
the large, PlinyCompute presents the programmer with a very high-level,
declarative interface, relying on automatic, relational-database style
optimization to figure out how to stage distributed computations. However, in
the small, PlinyCompute presents the capable systems programmer with a
persistent object data model and API (the "PC object model") and associated
memory management system that has been designed from the ground-up for high
performance, distributed, data-intensive computing. This contrasts with most
other Big Data systems, which are constructed on top of the Java Virtual
Machine (JVM), and hence must at least partially cede performance-critical
concerns such as memory management (including layout and de/allocation) and
virtual method/function dispatch to the JVM. This hybrid approach---declarative
in the large, trusting the programmer's ability to utilize PC object model
efficiently in the small---results in a system that is ideal for the
development of reusable, data-intensive tools and libraries. Through extensive
benchmarking, we show that implementing complex objects manipulation and
non-trivial, library-style computations on top of PlinyCompute can result in a
speedup of 2x to more than 50x or more compared to equivalent implementations
on Spark.Comment: 48 pages, including references and Appendi
The role of concurrency in an evolutionary view of programming abstractions
In this paper we examine how concurrency has been embodied in mainstream
programming languages. In particular, we rely on the evolutionary talking
borrowed from biology to discuss major historical landmarks and crucial
concepts that shaped the development of programming languages. We examine the
general development process, occasionally deepening into some language, trying
to uncover evolutionary lineages related to specific programming traits. We
mainly focus on concurrency, discussing the different abstraction levels
involved in present-day concurrent programming and emphasizing the fact that
they correspond to different levels of explanation. We then comment on the role
of theoretical research on the quest for suitable programming abstractions,
recalling the importance of changing the working framework and the way of
looking every so often. This paper is not meant to be a survey of modern
mainstream programming languages: it would be very incomplete in that sense. It
aims instead at pointing out a number of remarks and connect them under an
evolutionary perspective, in order to grasp a unifying, but not simplistic,
view of the programming languages development process
The Family of MapReduce and Large Scale Data Processing Systems
In the last two decades, the continuous increase of computational power has
produced an overwhelming flow of data which has called for a paradigm shift in
the computing architecture and large scale data processing mechanisms.
MapReduce is a simple and powerful programming model that enables easy
development of scalable parallel applications to process vast amounts of data
on large clusters of commodity machines. It isolates the application from the
details of running a distributed program such as issues on data distribution,
scheduling and fault tolerance. However, the original implementation of the
MapReduce framework had some limitations that have been tackled by many
research efforts in several followup works after its introduction. This article
provides a comprehensive survey for a family of approaches and mechanisms of
large scale data processing mechanisms that have been implemented based on the
original idea of the MapReduce framework and are currently gaining a lot of
momentum in both research and industrial communities. We also cover a set of
introduced systems that have been implemented to provide declarative
programming interfaces on top of the MapReduce framework. In addition, we
review several large scale data processing systems that resemble some of the
ideas of the MapReduce framework for different purposes and application
scenarios. Finally, we discuss some of the future research directions for
implementing the next generation of MapReduce-like solutions.Comment: arXiv admin note: text overlap with arXiv:1105.4252 by other author
A Lightweight and Flexible Mobile Agent Platform Tailored to Management Applications
Mobile Agents (MAs) represent a distributed computing technology that
promises to address the scalability problems of centralized network management.
A critical issue that will affect the wider adoption of MA paradigm in
management applications is the development of MA Platforms (MAPs) expressly
oriented to distributed management. However, most of available platforms impose
considerable burden on network and system resources and also lack of essential
functionality. In this paper, we discuss the design considerations and
implementation details of a complete MAP research prototype that sufficiently
addresses all the aforementioned issues. Our MAP has been implemented in Java
and tailored for network and systems management applications.Comment: 7 pages, 5 figures; Proceedings of the 2006 Conference on Mobile
Computing and Wireless Communications (MCWC'2006
An Efficient Thread Mapping Strategy for Multiprogramming on Manycore Processors
The emergence of multicore and manycore processors is set to change the
parallel computing world. Applications are shifting towards increased
parallelism in order to utilise these architectures efficiently. This leads to
a situation where every application creates its desirable number of threads,
based on its parallel nature and the system resources allowance. Task
scheduling in such a multithreaded multiprogramming environment is a
significant challenge. In task scheduling, not only the order of the execution,
but also the mapping of threads to the execution resources is of a great
importance. In this paper we state and discuss some fundamental rules based on
results obtained from selected applications of the BOTS benchmarks on the
64-core TILEPro64 processor. We demonstrate how previously efficient mapping
policies such as those of the SMP Linux scheduler become inefficient when the
number of threads and cores grows. We propose a novel, low-overhead technique,
a heuristic based on the amount of time spent by each CPU doing some useful
work, to fairly distribute the workloads amongst the cores in a
multiprogramming environment. Our novel approach could be implemented as a
pragma similar to those in the new task-based OpenMP versions, or can be
incorporated as a distributed thread mapping mechanism in future manycore
programming frameworks. We show that our thread mapping scheme can outperform
the native GNU/Linux thread scheduler in both single-programming and
multiprogramming environments.Comment: ParCo Conference, Munich, Germany, 201
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