910 research outputs found
On the Computation Power of Name Parameterization in Higher-order Processes
Parameterization extends higher-order processes with the capability of
abstraction (akin to that in lambda-calculus), and is known to be able to
enhance the expressiveness. This paper focuses on the parameterization of
names, i.e. a construct that maps a name to a process, in the higher-order
setting. We provide two results concerning its computation capacity. First,
name parameterization brings up a complete model, in the sense that it can
express an elementary interactive model with built-in recursive functions.
Second, we compare name parameterization with the well-known pi-calculus, and
provide two encodings between them.Comment: In Proceedings ICE 2015, arXiv:1508.0459
A nearly perfect omnidirectional shear-horizontal (SH) wave transducer based on a thickness poled, thickness-shear (d15) piezoelectric ring
The fundamental shear horizontal (SH0) wave in plates is of great importance
in the field of nondestructive testing (NDT) and structural health monitoring
(SHM) since it is the unique non-dispersive guided wave mode. For practical
applications, a phased array system based on omnidirectional SH0 wave
transducers is most useful as it can cover a wide range of a plate. However, so
far very few omnidirectional SH wave transducers have been developed. In this
work, we proposed an omnidirectional SH piezoelectric transducer (OSH-PT) based
on a thickness poled piezoelectric ring. The ring is equally divided into
twelve sectors and the electric field is circumferentially applied, resulting
in a new thickness-shear (d15) mode. Finite element analysis shows that the
proposed OSH-PT can excite single-mode SH0 wave and receive the SH0 wave only.
Experiments were then conducted to examine the performance of the proposed
OSH-PT. Results indicated that it can generate and receive single-mode SH0 wave
in a wide frequency range with nearly uniform sensitivities along all
directions. Considering its quite simple configuration, compact size and low
cost, the proposed OSH-PT is expected to greatly promote the applications of SH
waves in the field of NDT and SHM
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