Abstract: An object of the present disclosure is to provide a communication system capable of constantly performing monitoring in conjunction with client signals regardless of switching due to a failure in a network.

Abstract: To provide a prestressed concrete which can be used for non-primary structural members such as general building members by using a chemical stress induced by an expansive material and a mechanical stress induced by a rust-resistant wire together and achieving reduction in weight and suppression of cracking. A prestressed concrete for non-primary structural members is characterized in that a mechanical stress induced by a tensional material and a chemical stress induced by an expansive material for a concrete are introduced and that the tensional material is a rust-resistant continuous fiber reinforcing wire.

Abstract: To provide a prestressed concrete which can be used for non-primary structural members such as general building members by using a chemical stress induced by an expansive material and a mechanical stress induced by a rust-resistant wire together and achieving reduction in weight and suppression of cracking. A prestressed concrete for non-primary structural members is characterized in that a mechanical stress induced by a tensional material and a chemical stress induced by an expansive material for a concrete are introduced and that the tensional material is a rust-resistant continuous fiber reinforcing wire.

Abstract: A method of producing an insert which is to be embedded in a concrete structure comprises preparing a flexible mold, setting a cylindrical core in the flexible mold, pouring a powdered ceramic material into the flexible mold in such a manner to fully cover the cylindrical core, compressing the flexible mold from the outside to compress the powdered ceramic material thereby to produce a molded green body that holds therein the cylindrical core, removing the molded green body together with the cylindrical core from the flexible mold, removing the cylindrical core from the molded green body proper by turning the cylindrical core in a releasing direction, and baking the molded green body proper to produce the insert. The cylindrical core has a male thread portion formed thereon and thus, upon removal of the cylindrical core from the molded green body proper, the molded green body has a female thread bore portion.

Abstract: A method of producing an insert which is to be embedded in a concrete structure comprises preparing a flexible mold, setting a cylindrical core in the flexible mold, pouring a powdered ceramic material into the flexible mold in such a manner to fully cover the cylindrical core, compressing the flexible mold from the outside to compress the powdered ceramic material thereby to produce a molded green body that holds therein the cylindrical core, removing the molded green body together with the cylindrical core from the flexible mold, removing the cylindrical core from the molded green body proper by turning the cylindrical core in a releasing direction, and baking the molded green body proper to produce the insert. The cylindrical core has a male thread portion formed thereon and thus, upon removal of the cylindrical core from the molded green body proper, the molded green body has a female thread bore portion.