17,314 research outputs found
Approximate polynomial preconditioning applied to biharmonic equations on vector supercomputers
Applying a finite difference approximation to a biharmonic equation results in a very ill-conditioned system of equations. This paper examines the conjugate gradient method used in conjunction with the generalized and approximate polynomial preconditionings for solving such linear systems. An approximate polynomial preconditioning is introduced, and is shown to be more efficient than the generalized polynomial preconditionings. This new technique provides a simple but effective preconditioning polynomial, which is based on another coefficient matrix rather than the original matrix operator as commonly used
Influence of aggregate size and fraction on shrinkage induced micro-cracking of mortar and concrete
In this paper, the influence of aggregate size and volume fraction on
shrinkage induced micro-cracking and permeability of concrete and mortar was
investigated. Nonlinear finite element analyses of model concrete and mortar
specimens were performed. The aggregate diameter was varied between 2 and 16
mm. Furthermore, a range of volume fractions between 0.1 and 0.5 was studied.
The nonlinear analyses were based on a 2D lattice approach in which aggregates
were simplified as monosized cylindrical inclusions. The analysis results were
interpreted by means of crack width and change of permeability. The results
show that increasing aggregate diameter (at equal volume fraction) and
decreasing volume fraction (at equal aggregate diameter) greatly increases
permeability.Comment: 12th International Conference on Fracture (ICF 12
Which Emotional Behaviors are Actions?
There is a wide range of things we do out of emotion. For example, we smile with pleasure, our voices drop when we are sad, we recoil in shock or jump for joy, we apologize to others out of remorse. It is uncontroversial that some of these behaviors are actions. Clearly, apologizing is an action if anything is. Things seem less clear in the case of other emotional behaviors. Intuitively, the drop in a sad person’s voice is something that happens to her, rather than something she actively performs. Perhaps more interestingly, even jumping for joy can seem a problematic case: although its execution involves the active performance of certain movements, it has been argued to contrast, e.g., with an act of apology, in that it is not performed in order to achieve some end, such as repairing a relationship. This can make this behavior seem considerably different from paradigm actions.
Our central concern in this paper is with which emotional behaviors should be classed as actions and why..
Multi-channel Wireless Networks with Infrastructure Support: Capacity and Delay
In this paper, we propose a novel multi-channel network with infrastructure
support, called an \textit{MC-IS} network, which has not been studied in the
literature. To the best of our knowledge, we are the first to study such an
\textit{MC-IS} network. Our \textit{MC-IS} network is equipped with a number of
infrastructure nodes which can communicate with common nodes using a number of
channels where a communication between a common node and an infrastructure node
is called an infrastructure communication and a communication between two
common nodes is called an ad-hoc communication. Our proposed \textit{MC-IS}
network has a number of advantages over three existing conventional networks,
namely a single-channel wireless ad hoc network (called an \textit{SC-AH}
network), a multi-channel wireless ad hoc network (called an \textit{MC-AH}
network) and a single-channel network with infrastructure support (called an
\textit{SC-IS} network). In particular, the \textit{network capacity} of our
proposed \textit{MC-IS} network is times higher than that of
an \textit{SC-AH} network and an \textit{MC-AH} network and the same as that of
an \textit{SC-IS} network, where is the number of nodes in the network. The
\textit{average delay} of our \textit{MC-IS} network is times
lower than that of an \textit{SC-AH} network and an \textit{MC-AH} network, and
times lower than the average delay of an \textit{SC-IS} network,
where and denote the number of channels dedicated for infrastructure
communications and the number of interfaces mounted at each infrastructure
node, respectively.Comment: 12 pages, 6 figures, 3 table
On Capacity and Delay of Multi-channel Wireless Networks with Infrastructure Support
In this paper, we propose a novel multi-channel network with infrastructure
support, called an MC-IS network, which has not been studied in the literature.
To the best of our knowledge, we are the first to study such an MC-IS network.
Our proposed MC-IS network has a number of advantages over three existing
conventional networks, namely a single-channel wireless ad hoc network (called
an SC-AH network), a multi-channel wireless ad hoc network (called an MC-AH
network) and a single-channel network with infrastructure support (called an
SC-IS network). In particular, the network capacity of our proposed MC-IS
network is times higher than that of an SC-AH network and an
MC-AH network and the same as that of an SC-IS network, where is the number
of nodes in the network. The average delay of our MC-IS network is times lower than that of an SC-AH network and an MC-AH network, and
times lower than the average delay of an SC-IS network, where
and denote the number of channels dedicated for infrastructure
communications and the number of interfaces mounted at each infrastructure
node, respectively. Our analysis on an MC-IS network equipped with
omni-directional antennas only has been extended to an MC-IS network equipped
with directional antennas only, which are named as an MC-IS-DA network. We show
that an MC-IS-DA network has an even lower delay of compared with an SC-IS network and our
MC-IS network. For example, when and , an
MC-IS-DA network can further reduce the delay by 24 times lower that of an
MC-IS network and reduce the delay by 288 times lower than that of an SC-IS
network.Comment: accepted, IEEE Transactions on Vehicular Technology, 201
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