BUKU ABSTRAK - Universiti Putra Malaysia

Petri Net Controlled Grammars: The Case of Special Petri Nets
Assoc. Prof. Dr. Mohd. Hasan Selamat
Sherzod Turaev
Faculty of Computer Science and Information Technology, University Putra Malaysia,
43400 UPM Serdang, Selangor, Malaysia.
+603-8946 6517; hasan@fsktm.upm.edu.my
Keywords: Petri net controlled grammars, petri nets, grammars, grammars with regulated rewriting
Effect of Normal Contaminants on the Power of ZMAD
Assoc. Prof. Dr. Noor Akma Ibrahim
Lim Fong Peng, Fauziah Maarof and Kassim Haron
Faculty of Science, University Putra Malaysia,
43400 UPM Serdang, Selangor, Malaysia.
+603-8946 6873; nakma@putra.upm.edu.my
Keywords: Coefficient of determination, median absolute deviation, normal contaminants
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Science, Technology & Engineering
A Petri net controlled grammar is a context-free grammar equipped with a Petri net, whose transitions are
labelled with rules of the grammar or the empty string, and the associated language consists of all terminal strings
which can be derived in the grammar and the sequence of rules in every terminal derivation corresponds to some
occurrence sequence of transitions of the Petri net which is enabled at the initial marking and finished at a final
marking of the net. We present some results on the generative capacity of such grammars so that the associated
Petri nets are restricted to some known special classes of Petri nets.
Alternative to the least square coefficient of determination, R2OLS, the coefficient of determination based
on median absolute deviation, R2MAD, is an attractive consideration in the construction of a goodness-of-fit test
based on regression and correlation, due to its robustness. This paper presents the power study on a goodnessof-fit
test statistic, ZMAD = 1 -R2MAD, used for testing samples from the standard logistic distribution against
clean and contaminated alternative distributions. Contamination is introduced to investigate perseverance of the
robustness property of R2MAD. For lognormal and exponential alternatives, observed values of ZMAD, denoted
as Z*MAD, and observed values of ZOLS = 1 - R2OLS, denoted as Z*OLS, are simulated for various sample
sizes (n =10, 20, 30, 50, 100) and percentage of contamination (5%, 15%, 25%, 40%) in presence of normal (3,
0.2) contaminants for different percentiles (? = 0.01, 0.025, 0.05, 0.1). Power is represented by the percentage
of rejections assuming that the alternative is true. The results indicate that for the cases with and without
contamination the test statistic ZMAD performs as well as ZOLS, except for cases with normal contaminants,
whereby the power decreases markedly as percentage of normal contaminants increases.