What operation on relations R and S produces the relation shown below?

Due to GPS roll over of the clock cycle，GPS receivers may give the wrong time and position or may lock up permanently on（）.

（）is not included in the main contents of the operation and maintenance of the information system.

（）is not included in the main contents of the operation and maintenance of the information system.

To safeguard the operator and other personnel working on or near a hoisting operation which of the following precautions should be observed?（）

The amount and accuracy of the information provided on the different charts（）considerably.

（）is for the operation ordering and the information exchange by Internet among the firms.

Which MySQL utility program should you to process and sort the slow Query log based on query time or average query time?（）

（）is entitled to enter into，with a shipper，any agreement，stipulation，condition，reservation or exception as to the responsibility and liability of the carrier or the ship for the loss of or damage to，or in connection with，the custody and care and handling of the goods prior to the loading on，and subsequent to the discharge from，the ship on which the goods are carried by sea.

A salvor may be（）the whole or part of the payment due under Salvage Convention to the extent that the salvage operations have become necessary or more difficult because of fault or neglect on his part or if the salvor has been guilty of fraud or other dishonest conduct.

The more time you spend on the Internet, the less time you are with your family and friends.

●The Systems Development Life Cycle (SDLC) is a process of creating or altering information systems, and the models and methodologies that people use to develop these systems. Sequential SDLC models, such as (72), focus on complete and correct planning to guide large projects and risks to successful and predictable results.