20 Thus, any product enhancements that involve alerting provide an additional layer of checking, not a substitution for checking.
Fear has been clogging the city for years, through escalating layers of checks and guards, and more and more blocked-off roads.
Several layers of checks mean the result, which is impossible to predict, will be announced very late after polls close on Sunday night.
The extraordinary administrative error was not spotted until it was too late, despite "seven or eight" layers of checks where the mistake could have been identified.
"We don't want to create all these layers of checks and balances," explained Dennis M. Walcott, the deputy mayor who oversees education, who described the three decades of school board rule as "dancing to multiple masters".
Security will include a police and military presence and private security guards carrying out several layers of checks, including individual body searches using metal detectors, there will be video surveillance cameras and a ban on rucksacks, motorcycle helmets and banners with political or offensive messages.
Three layers of checks must be passed before an aglet is allowed access to a computer, and one of these layers can be customised for example to reject aglets whose owners do not have subscriptions to a commercial database.The result is that letting someone else's aglet on to your computer should be about as risky as downloading an applet from the Net, which is generally considered safe.
Although they understand that it is meant to provide extra layers of checks and balances, "it doesn't make an awful lot of sense," said Paul Ashworth, a Canadian economist at Capital Economics.
If SVD detects any false fault, it is also re-evaluated by the SDF, i.e., the model has two layers of checking to balance the false alarms.
