Need help. I need regular expressions that correlate to computer science Write a

Question

Need help. I need regular expressions that correlate to computer science

Write a regular expression that defines a simple musical score. Notes are represented by their duration, immediately followed by the frequency and then optionally a sharp,"#", or a flat, "b". The frequency is specified by the capital letters A..G. The frequency letter "R" represents a rest or no sound. A rest never has a sharp or flat. The duration is a number representing the inverse of the time per bar. A quarter note is represented as "4", and eight note as an "8". The possible values are 1, 2, 4, 8 and 16. There can be one or more spaces between the notes. Write a Deterministic Finite State Automata (DFA) for two of the above languages. This should be a circle and arrow diagram with the edges labeled with the input symbol.

Explanation / Answer

Hi below i explained a Relational Database Approach to Polyphonic Music Search Systems Using Regular Expressions for your reference,

ANALYSIS

As much as worst case running times tend to be overlypessimistic, average case running times will hide the enormity of the worst case. With this in mind, we present both worst and average case performance analysis.

Example Regular Expression Query

([< p11, d11 >< p12, d12 > . . . < p1q, d1q >]

[< pl1, dl1 >< pl2, dl2 > . . . < plr, dlr >])?{m, x}

We begin with the generalized query. Though it does not demonstrate matching of series of patterns or “or’s” of patterns, methods for accomplishing those portions of a query are computationally similar to a portion of a query it does demonstrate: matching ranges of a pattern. The query would be translated into SQL.

Corresponding SQL Query

select S1.id, Sl.id from

notes N11, ..., notes Nlr,

clusters C1, ..., clusters C1q, ...

clusters Cl1, ..., clusters Clr,

scores S1, ..., scores Sl where

N11.pitch=p11 and N11.duration=d11 and ...

and Nlr.pitch=plr and Nlr.duration=dlr and

C11.id=C12.id and ... and

C1q-1.id=C1q.id and ... and

Cl1.id=Cl2.id and ... and

Clr-1.id=Clr.id and

C1.note=N11.id and ... and

C1q.note=N1q.id and ... and

Cl1.note=Nl1.id and ... and

Clr.note=Nlr.id and

S1.cluster=C11.id and ... and

Sl.cluster=Cl1.id and

S1.next=S2.id and ... and

Sl-1.next=Sl.id and

S1.c_num-Sl.c_num>=(m*count) and

S1.c_num-Sl.c_num<=(x*count)

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