3,468 research outputs found
Incentive compatible route coordination of crowdsourced resources and its application to GeoPresence-as-a-Service
With the recent trend in crowdsourcing, i.e., using the power of crowds to assist in satisfying demand, the pool of resources suitable for GeoPresen- ce-capable systems has expanded to include already roaming devices, such as mobile phones, and moving vehicles. We envision an environment, in which the motion of these crowdsourced mobile resources is coordinated, according to their preexisting schedules to satisfy geo-temporal demand on a mobility field. In this paper, we propose an incentive compatible route coordination mechanism for crowdsourced resources, in which participating mobile agents satisfy geo-temporal requests in return for monetary rewards. We define the Flexible Route Coordination (FRC) problem, in which an agent's exibility is exploited to maximize the coverage of a mo- bility field, with an objective to maximize the revenue collected from sat- isfied paying requests. Given that the FRC problem is NP-hard, we define an optimal algorithm to plan the route of a single agent on a graph with evolving labels, then we use that algorithm to define a 1 2 -approximation algorithm to solve the problem in its general model, with multiple agents. Moreover, we define an incentive compatible, rational, and cash-positive payment mechanism, which guarantees that an agent's truthfulness about its exibility is an ex-post Nash equilibrium strategy. Finally, we analyze the proposed mechanisms theoretically, and evaluate their performance experimentally using real mobility traces from urban environments.Supported in part by NSF Grants, #1430145, #1414119, #1347522, #1239021, and #1012798
Many-Task Computing and Blue Waters
This report discusses many-task computing (MTC) generically and in the
context of the proposed Blue Waters systems, which is planned to be the largest
NSF-funded supercomputer when it begins production use in 2012. The aim of this
report is to inform the BW project about MTC, including understanding aspects
of MTC applications that can be used to characterize the domain and
understanding the implications of these aspects to middleware and policies.
Many MTC applications do not neatly fit the stereotypes of high-performance
computing (HPC) or high-throughput computing (HTC) applications. Like HTC
applications, by definition MTC applications are structured as graphs of
discrete tasks, with explicit input and output dependencies forming the graph
edges. However, MTC applications have significant features that distinguish
them from typical HTC applications. In particular, different engineering
constraints for hardware and software must be met in order to support these
applications. HTC applications have traditionally run on platforms such as
grids and clusters, through either workflow systems or parallel programming
systems. MTC applications, in contrast, will often demand a short time to
solution, may be communication intensive or data intensive, and may comprise
very short tasks. Therefore, hardware and software for MTC must be engineered
to support the additional communication and I/O and must minimize task dispatch
overheads. The hardware of large-scale HPC systems, with its high degree of
parallelism and support for intensive communication, is well suited for MTC
applications. However, HPC systems often lack a dynamic resource-provisioning
feature, are not ideal for task communication via the file system, and have an
I/O system that is not optimized for MTC-style applications. Hence, additional
software support is likely to be required to gain full benefit from the HPC
hardware
TransEdge: Supporting Efficient Read Queries Across Untrusted Edge Nodes
We propose Transactional Edge (TransEdge), a distributed transaction
processing system for untrusted environments such as edge computing systems.
What distinguishes TransEdge is its focus on efficient support for read-only
transactions. TransEdge allows reading from different partitions consistently
using one round in most cases and no more than two rounds in the worst case.
TransEdge design is centered around this dependency tracking scheme including
the consensus and transaction processing protocols. Our performance evaluation
shows that TransEdge's snapshot read-only transactions achieve an 9-24x speedup
compared to current byzantine systems
Accelerating Reconfigurable Financial Computing
This thesis proposes novel approaches to the design, optimisation, and management of reconfigurable
computer accelerators for financial computing. There are three contributions. First, we propose novel
reconfigurable designs for derivative pricing using both Monte-Carlo and quadrature methods. Such
designs involve exploring techniques such as control variate optimisation for Monte-Carlo, and multi-dimensional
analysis for quadrature methods. Significant speedups and energy savings are achieved
using our Field-Programmable Gate Array (FPGA) designs over both Central Processing Unit (CPU)
and Graphical Processing Unit (GPU) designs. Second, we propose a framework for distributing computing
tasks on multi-accelerator heterogeneous clusters. In this framework, different computational
devices including FPGAs, GPUs and CPUs work collaboratively on the same financial problem based
on a dynamic scheduling policy. The trade-off in speed and in energy consumption of different accelerator
allocations is investigated. Third, we propose a mixed precision methodology for optimising
Monte-Carlo designs, and a reduced precision methodology for optimising quadrature designs. These
methodologies enable us to optimise throughput of reconfigurable designs by using datapaths with
minimised precision, while maintaining the same accuracy of the results as in the original designs
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