Such units are small programs that can autonomously run on the static sensor nodes and communicate according to the Linda tuple space
based methods partition the filter set according to the number of specified bits in the filter and then probe the partitions or a subset of the partitions using simple exact match searches, such as Tuple Space
, Conflict-Free Rectangle search .
The shared data pool in the Linda concept is called tuple space
, because its access unit is the tuple, similar to tuples in PROSET; thus it is rather natural to combine both models on this basis.
First of all, this paper studies the current development of mobile agent computing, briefly introduces "Ubiquitous Computing" and "Tuple Space
the data-producing process generates a new data object (called a tuple) and sets it adrift in a region called tuple space
--a tuple space
is an abstract storage location where tuples are deposited and retrieved by the software entities which are called processes.
This shared pool is known as a tuple space
. The Linda communication model contains three communication operations: in, which removes a tuple from tuple space
, based on its arity and the values of some of its fields, filling in the remaining fields from the retrieved tuple; read (rd), which does the same except that it copies the tuple from tuple space
; and out, which places a tuple in tuple space
Linda contains a few simple commands operating on a tuple space
. Adding these tuple space
commands to an existing base language produces a parallel programming dialect.
While the behaviour of a tuple space
in response to communication events is fixed, the behaviour of a tuple centre can be tailored to the application needs by defining a set of specification tuples expressed in the ReSpecT language, which define how a tuple centre should react to incoming / outgoing communication events.
There is just one way to communicate in CLP, not as in Linda where there is a dialect specific way of communicating in the small and the tuple space
way of communicating at the next level .
Since everyone shares the tuple space
, the "look and feel" a developer gets is somewhat similar to that of the shared-memory worldview.
Specifically, observe that the content of a Tuple Space
, i.e., a multiset of tuples, can be represented directly by a multiset of unit clauses (also called facts), and that the basic tuple space
operations of Linda, out and in, are variants of Prolog's database manipulation operations assert and retract over a database of facts; in is a degenerate form of retract in the sense that it uses a home-brewed form of matching, rather than fullfledged unification.