Abstract: A technology capable of reducing a data amount required for a estimation processing while maintaining accuracy for estimation of a virtual deformation state of an attachment which receives external force in a crane is provided. A deformation state of each of a boom (first attachment element) and a jib (second attachment element) configuring an attachment connected to a crane main body so as to perform a derricking motion is estimated according to a crane model. The crane model is a model indicating a correlation among an “acting force factor” for specifying an acting state of force on the attachment connected to the crane main body so as to perform the derricking motion, a “posture factor” for specifying respective postures of the boom and the jib, and “angle changes (elevation angle deviations ??1 and ??2)” indicating respective deformation states of the boom and the jib.

Abstract: A technology capable of facilitating work of selecting a crane of a type which is appropriate in view of a work site situation is provided. When the crane of the type satisfying specified conditions is present, information regarding the crane of the type is selectively provided to a user such as a construction work planner through a terminal output interface. A “first specified condition” included in the specified conditions is the condition of having such a load-lifting level that an interval between an upper end of a building and a lower end of a material which is a suspended load is equal to or larger than a threshold in a state where a crane is arranged at a specified place in an area around the building and an attachment is in a specified posture.