CPS CTLR CHRONICLED LOSS OF SEPARATION DURING TAXI EVENT; DUE TO PLT ERROR.

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WHILE WORKING GND CTL; CESSNA CALLED READY TO TAXI FROM ONE OF THE FBO'S. I ISSUED TAXI INSTRUCTIONS AS 'TAXI TO RWY 30L; INTXN M;' WITHOUT A SPECIFIC RTE FOR THE ACFT SINCE HE WAS ON THE RAMP FACING A 'PREFERRED' TAXI RTE THAT WOULD NOT HAVE ALLOWED HIM TO CROSS ANY OF THE ACTIVE RWYS. I OBSERVED THE ACFT TURN ON THE RAMP TO A TXWY THAT WOULD HAVE ALLOWED HIM TO CROSS A RWY. I IMMEDIATELY ISSUED A TAXI RTE AND A RESTR TO HOLD SHORT OF THE FIRST TXWY WHILE HE WAS STILL ON THE RAMP. THE ACFT DID NOT ACKNOWLEDGE MY XMISSION; NOR THE 8 ATTEMPTS TO CONTACT HIM. HE SUBSEQUENTLY CROSSED THE ACTIVE RWY WITH A TAMPICO ON FINAL THAT HAD BEEN CLRED FOR A TOUCH AND GO. LOSS OF SEPARATION OCCURRED AS THE TAMPICO CROSSED THE THRESHOLD AS THE CESSNA WAS XING AT THE DEP END OF THE RWY. SPECIFIC TAXI RTE INSTRUCTIONS WOULD HAVE BEEN ONE OF THE POSSIBLE REMEDIES AND OR HOLD SHORT INSTRUCTIONS. THE PLT IN COMPLIANCE WITH FAR 91.129 MAINTAINING COM WITH ATC WHILE IN THE CLASS D AND ON THE ARPT WOULD HAVE BEEN THE PRIME SOLUTION FROM MY PERSPECTIVE. ONCE THE ACFT HAD REACHED THE INTENDED RWY OF DEP; HE CALLED THE TWR READY FOR DEP. HE DID NOT HEAR THE TWR'S REPLY (WHICH WAS THE 9TH ATC COM HE MISSED). HE CALLED THE TWR AGAIN; AND ACKNOWLEDGED THE TWR'S INSTRUCTION TO CONTACT GND CTL. IT HAS THE APPEARANCE THE PLT POSSIBLY TURNED HIS RADIO BACK UP AFTER CALLING THE TWR THE SECOND TIME; AS COMS WERE FINE ON THE TWR AND GND FREQ AFTER THAT.