Abstract: A small hydropower of a novel concept, comprising: two side supports; a main rotation axis provided on the upper end between the two side supports; a rotation body for rotating around the main rotation axis; fillable-then-emptiable water containers which are provided around the circumference of the rotation body, remain horizontally level, add weight by being filled with a certain amount of water when positioned at the top center of the rotation body during rotation, and remove the weight by spilling when positioned at the bottom center; a selective water supply device which can provide, to a fillable-then-emptiable water container that is positioned at the top center of the rotation body, water, and which temporarily stops discharging water until the next fillable-then-emptiable water container is positioned, if one fillable-then-emptiable water container is completely filled.

Abstract: A small hydropower of a novel concept, comprising: two side supports; a main rotation axis provided on the upper end between the two side supports; a rotation body for rotating around the main rotation axis; fillable-then-emptiable water containers which are provided around the circumference of the rotation body, remain horizontally level, add weight by being filled with a certain amount of water when positioned at the top center of the rotation body during rotation, and remove the weight by spilling when positioned at the bottom center; a selective water supply device which can provide, to a fillable-then-emptiable water container that is positioned at the top center of the rotation body, water, and which temporarily stops discharging water until the next fillable-then-emptiable water container is positioned, if one fillable-then-emptiable water container is completely filled.

Abstract: There is provided a propeller-type vertical take-off and land aircraft with a torque removal and balancing function, the aircraft comprising: a body; a body support frame to support the body; at least one main rotor blade provided out of the body; a rotation rotor coupled centrally to the main rotor blade; a rotation drive axis operatively coupled to the rotation rotor; a main rotor motor operatively coupled to the rotation drive axis; and a counter-torque and balancing wheel disposed under the body support frame to be coupled to a torque-removal inverse motor to be configured to rotate in an opposite direction to a rotation of the main rotor blade, wherein the counter-torque and balancing wheel is housed in the body.

Abstract: There is provided a propeller-type vertical take-off and land aircraft with a torque removal and balancing function, the aircraft comprising: a body; a body support frame to support the body; at least one main rotor blade provided out of the body; a rotation rotor coupled centrally to the main rotor blade; a rotation drive axis operatively coupled to the rotation rotor; a main rotor motor operatively coupled to the rotation drive axis; and a counter-torque and balancing wheel disposed under the body support frame to be coupled to a torque-removal inverse motor to be configured to rotate in an opposite direction to a rotation of the main rotor blade, wherein the counter-torque and balancing wheel is housed in the body.

Abstract: There is disclosed a collaboration system using an open public network for providing collaboration services among a plurality of enterprises including a server configured to implement a plurality of processes for the collaboration services; a user terminal connecting to the server via the open public network to restrictedly uses data generated by the processes according to a user permission; and a database configured to store the data generated by the processes, wherein the server implements the processes comprising a project development process, a data change process, a general business process and a collaboration process, and the server restrictedly messages an event generated during the implementation of the processes to the user terminal according to the user permission.