20 research outputs found
Serializing the Parallelism in Parallel Communicating Pushdown Automata Systems
No full textWe consider parallel communicating pushdown automata systems (PCPA) and define a property called known communication for it. We use this property to prove that the power of a variant of PCPA, called returning centralized parallel communicating pushdown automata (RCPCPA), is equivalent to that of multi-head pushdown automata. The above result presents a new sub-class of returning parallel communicating pushdown automata systems (RPCPA) called simple-RPCPA and we show that it can be written as a finite intersection of multi-head pushdown automata systems
International Journal of Foundations of Computer Science c ○ World Scientific Publishing Company DISTRIBUTED PROCESSING IN AUTOMATA ∗ KAMALA KRITHIVASAN
No full textWith distributed computing beginning to play a major role in modern Computer Science, the theory of grammar systems and distributed automata has been developed in order to model distributed computing. In this paper, we introduce the notion of distributed automata in the sequential sense. Distributed Automata are a group of automata working in unison to accept one language. We build the theory of distributed automata for FSA and PDA in different modes of acceptance like the t-mode, *-mode, = k-mode, ≤ k-mode and ≥ k-mode. We then analyze the acceptance power of each automata in all the above modes. We present proofs that distributed FSA do not have any additional power over “centralized ” FSAs in any of the modes, while distributed PDA with only two components is as powerful as Turing Machines in all of the modes. We give proofs for the equivalence of all modes in the case of PDAs. We also study a restricted version of distributed PDA called k-turn distributed PDA
A Comparative study of fine needle aspiration cytology versus fine needle non aspiration cytology Versus ultrasound guided fine needle aspiration cytology in the cytological evaluation of thyroid lesions
No full textAIMS & OBJECTIVES:
To evaluate the efficacy of fine-needle non-aspiration cytology (FNNAC) with
that of standard fine-needle aspiration cytology (FNAC) and USG guided
FNAC of thyroid lesions as regards to cellular and hemorrhagic yield.
MATERIALS AND METHODS:
This study included 75 patients with thyroid lesions, out of which 25 cases
underwent standard FNAC, 25 cases underwent FNNAC and 25 cases
underwent USG guided FNAC. All the needle sampling procedures were
performed by a single surgeon. The samples were then assessed cytologically
using five parameters .i.e., background blood or clot,amount of cellular
material,degree of cellular degeneration,degree of cellular trauma and retention
of architecture and further categorised as unsuitable,adequate and diagnostically
superior for cytological evaluation.
RESULTS:
Analysis showed that more number of diagnostically superior
samples were obtained from FNNAC technique(72%) than that of
standard FNAC(44%), whereas FNAC yielded more number of
diagnostically adequate samples(52%) than that of FNNAC(24%),
diagnostically inadequate samples were equal with both standard
FNAC & FNNAC(4%). However, the diagnostic adequacy was equal
in both FNNAC and standard FNAC techniques in thyroid lesions.
On comparing FNNAC with that of USG guided FNAC, it was found
that superior quality smears were more in FNNAC technique(72%vs
48%), but diagnostically adequate samples are more in USG guided
FNAC than FNNAC(52% vs 24%). Also USG guided FNAC yielded
fewer unsuitable smears.
CONCLUSION:
For highly vascular organs like thyroid , FNNAC is the preferred
technique as there is better material with less admixture of blood by
yielding more number of superior quality smears. The use of
ultrasound enhances the diagnostic adequacy of FNAC by reducing
the number of unsuitable smears obtained in smaller and cystic
lesions
