7,785 research outputs found
Spatial CSMA: A Distributed Scheduling Algorithm for the SIR Model with Time-varying Channels
Recent work has shown that adaptive CSMA algorithms can achieve throughput
optimality. However, these adaptive CSMA algorithms assume a rather simplistic
model for the wireless medium. Specifically, the interference is typically
modelled by a conflict graph, and the channels are assumed to be static. In
this work, we propose a distributed and adaptive CSMA algorithm under a more
realistic signal-to-interference ratio (SIR) based interference model, with
time-varying channels. We prove that our algorithm is throughput optimal under
this generalized model. Further, we augment our proposed algorithm by using a
parallel update technique. Numerical results show that our algorithm
outperforms the conflict graph based algorithms, in terms of supportable
throughput and the rate of convergence to steady-state.Comment: This work has been presented at National Conference on Communication,
2015, held at IIT Bombay, Mumbai, Indi
Self-Assembly of Infinite Structures
We review some recent results related to the self-assembly of infinite
structures in the Tile Assembly Model. These results include impossibility
results, as well as novel tile assembly systems in which shapes and patterns
that represent various notions of computation self-assemble. Several open
questions are also presented and motivated
Sensitivity Analysis of Process Parameters in Laser Deposition
In laser cladding with powder injection process, process output parameters, including
melt pool temperature and melt pool dimensions, are critical for part quality. This paper uses
simulation and experiments to investigate the effect of the process input parameters: laser power,
powder mass flow rate, and scanning speed on the output parameters. Numerical simulations and
experiments are conducted using a factorial design. The results are statistically analyzed to
determine the significant factors and their interactions. The simulation results are compared to
experimental results. The quantitative agreement/disagreement is discussed and further research is
outlined.Mechanical Engineerin
Innovative Design Concept for the New Bangkok International Airport, NBIA
Thermal and visual comfort for the occupants of a
room are not defined by air temperature only, but also
radiation with its three components solar radiation,
daylight and heat radiation has to be taken into account
(among other factors such as humidity, air speed and
occupant activity and clothing levels). In hot climates the
optimization of room comfort is a challenging task due
to the high solar radiation over the whole year.
In intelligent buildings new material developments
are applied optimizing the building envelope in an
integral building design process. New solutions for
weather, noise and heat protection are developed, where
building envelope and installed mechanical equipment
work together creating optimal comfort at minimum
energy consumption.
This approach was used in the design of the New
Bangkok International Airport, NBIA to develop an
optimized building concept in a design team comprising
the architects, structural and mechanical engineers,
HVAC, acoustic and climate engineers
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View-dependent adaptive cloth simulation
This paper describes a method for view-dependent cloth simulation using dynamically adaptive mesh refinement and coarsening. Given a prescribed camera motion, the method adjusts the criteria controlling refinement to account for visibility and apparent size in the camera's view. Objectionable dynamic artifacts are avoided by anticipative refinement and smoothed coarsening. This approach preserves the appearance of detailed cloth throughout the animation while avoiding the wasted effort of simulating details that would not be discernible to the viewer. The computational savings realized by this method increase as scene complexity grows, producing a 2× speed-up for a single character and more than 4× for a small group
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