2,326 research outputs found
An Efficient Beam Steerable Antenna Array Concept for Airborne Applications
Deployment of a satellite borne, steerable antenna array with higher directivity and gain in Low Earth Orbit makes sense to reduce ground station complexity and cost, while still maintaining a reasonable link budget. The implementation comprises a digitally beam steerable phased array antenna integrated with a complete system, comprising the antenna, hosting platform, ground station, and aircraft based satellite emulator to facilitate convenient aircraft based testing of the antenna array and ground-space communication link. This paper describes the design, development and initial successful interim testing of the various subsystems. A two element prototype used in this increases the signal-to-noise ratio (SNR) by 3 dB which is corresponding to more than 10 times better bit error rate (BER)
Steering in computational science: mesoscale modelling and simulation
This paper outlines the benefits of computational steering for high
performance computing applications. Lattice-Boltzmann mesoscale fluid
simulations of binary and ternary amphiphilic fluids in two and three
dimensions are used to illustrate the substantial improvements which
computational steering offers in terms of resource efficiency and time to
discover new physics. We discuss details of our current steering
implementations and describe their future outlook with the advent of
computational grids.Comment: 40 pages, 11 figures. Accepted for publication in Contemporary
Physic
A Community Microgrid Architecture with an Internal Local Market
This work fits in the context of community microgrids, where members of a
community can exchange energy and services among themselves, without going
through the usual channels of the public electricity grid. We introduce and
analyze a framework to operate a community microgrid, and to share the
resulting revenues and costs among its members. A market-oriented pricing of
energy exchanges within the community is obtained by implementing an internal
local market based on the marginal pricing scheme. The market aims at
maximizing the social welfare of the community, thanks to the more efficient
allocation of resources, the reduction of the peak power to be paid, and the
increased amount of reserve, achieved at an aggregate level. A community
microgrid operator, acting as a benevolent planner, redistributes revenues and
costs among the members, in such a way that the solution achieved by each
member within the community is not worse than the solution it would achieve by
acting individually. In this way, each member is incentivized to participate in
the community on a voluntary basis. The overall framework is formulated in the
form of a bilevel model, where the lower level problem clears the market, while
the upper level problem plays the role of the community microgrid operator.
Numerical results obtained on a real test case implemented in Belgium show
around 54% cost savings on a yearly scale for the community, as compared to the
case when its members act individually.Comment: 16 pages, 15 figure
A survey of computational steering environments
Computational steering is a powerful concept that allows scientists to interactively control a computational process during its execution. In this paper, a survey of computational steering environments for the on-line steering of ongoing scientific and engineering simulations is presented. These environments can be used to create steerable applications for model exploration, algorithm experimentation, or performance optimization. For each environment the scope is identified, the architecture is summarized, and the concepts of the user interface is described. The environments are compared and conclusions and future research issues are given
Progressive Analytics: A Computation Paradigm for Exploratory Data Analysis
Exploring data requires a fast feedback loop from the analyst to the system,
with a latency below about 10 seconds because of human cognitive limitations.
When data becomes large or analysis becomes complex, sequential computations
can no longer be completed in a few seconds and data exploration is severely
hampered. This article describes a novel computation paradigm called
Progressive Computation for Data Analysis or more concisely Progressive
Analytics, that brings at the programming language level a low-latency
guarantee by performing computations in a progressive fashion. Moving this
progressive computation at the language level relieves the programmer of
exploratory data analysis systems from implementing the whole analytics
pipeline in a progressive way from scratch, streamlining the implementation of
scalable exploratory data analysis systems. This article describes the new
paradigm through a prototype implementation called ProgressiVis, and explains
the requirements it implies through examples.Comment: 10 page
Goal accomplishment tracking for automatic supervision of plan execution
It is common practice to break down plans into a series of goals or sub-goals in order to facilitate plan execution, thereby only burdening the individual agents responsible for their execution with small, easily achievable objectives at any one time, or providing a simple way of sharing these objectives amongst a group of these agents. Ensuring that plans are executed correctly is an essential part of any team management. To allow proper tracking of an agent's progress through a pre-planned set of goals, it is imperative to keep track of which of these goals have already been accomplished. This centralised approach is essential when the agent is part of a team of humans and/or robots, and goal accomplishment is not always being tracked at a low level. This paper presents a framework for an automated supervision system to keep track of changes in world states so as to chart progress through a pre-planned set of goals. An implementation of this framework on a mobile service robot is presented, and applied in an experiment which demonstrates its feasibility
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