At least one aspect of the present disclosure directs to a deformation amount measuring method is a method in which a sheet (101) is used that includes a first layer portion (111) having a first pattern (121) that includes a plurality of line drawings extending in a first direction, and a second layer portion (112) overlaid on the first layer portion (111) and having a second pattern (122) that includes a plurality of line drawings extending in a second direction different than the first direction. The method includes the steps of acquiring, from the sheet (101) that has been disposed on a measurement subject, post-deformation image data corresponding to a post-deformation image including a post-deformation moire produced as a result of a post-deformation first pattern (121) and second pattern (122) being overlaid and finding an amount of deformation of the measurement subject on the basis of the post-deformation image data.

A multiplication abacus device is provided, which includes a main body with a result display area, where the result display area has calculation result bits arranged in a matrix, the calculation result bits have numbers for displaying a calculation result, a plurality of sliding members, arranged in a matrix that can slide horizontally and longitudinally on the main body, and located on the calculation result bits, where adjacent M rows of sliding members slide longitudinally, and adjacent N columns of sliding members slide horizontally. After the sliding members do not obstruct one row of calculation result bits and do not obstruct one column of calculation result bits, a number of the calculation result bits in a crossed position is a calculation result of M?N. Through the above technical solution, a technical problem of learning multiplication in existing technologies being abstract and not intuitive enough has been solved.

A multiplication abacus device is provided, which includes a main body with a result display area, where the result display area has calculation result bits arranged in a matrix, the calculation result bits have numbers for displaying a calculation result, a plurality of sliding members, arranged in a matrix that can slide horizontally and longitudinally on the main body, and located on the calculation result bits, where adjacent M rows of sliding members slide longitudinally, and adjacent N columns of sliding members slide horizontally. After the sliding members do not obstruct one row of calculation result bits and do not obstruct one column of calculation result bits, a number of the calculation result bits in a crossed position is a calculation result of M?N. Through the above technical solution, a technical problem of learning multiplication in existing technologies being abstract and not intuitive enough has been solved.

This tool for recording the number of swings in a ball game includes a plurality of holed beads 20 and a cord 30 that is passed through the holes 20H of the beads 20 and that holds the beads 20 so that the beads 20 can slide, the cord 30 is formed from a cord material that does not stretch in an axial direction but that stretches in a diametrical direction and that is normally urged in a diameter-expanding direction, and the cord 30 constrict in diameter so as to elastically interlock with the walls of the holes 20H of the beads 20 and hold the beads 20 in position, whereby the beads do not shift even if a player strongly shakes the tool, the number of swings in the ball game can be reliably recorded and confirmed, and the tool is easily assembled.

As disclosed herein a computer system for secure database backup and recovery in a secure database network has N distributed data nodes. The computer system includes program instructions that include instructions to receive a database backup file, fragment the file using a fragment engine, and associate each fragment with one node, where the fragment is not stored on the associated node. The program instructions further include instructions to encrypt each fragment using a first encryption key, and store, randomly, encrypted fragments on the distributed data nodes. The program instructions further include instructions to retrieve the encrypted fragments, decrypt the encrypted fragments using the first encryption key, re-encrypt the decrypted fragments using a different encryption key, and store, randomly, the re-encrypted fragments on the distributed data nodes. A computer program product and method corresponding to the above computer system are also disclosed herein.

Mathematical teaching apparatuses and methods of use are provided herein. In one embodiment a mathematical teaching apparatus includes a frame having a plurality of spaced apart rods, and an equal number of beads disposed on each of the plurality of spaced apart rods to create beaded rows. Each of the equal number of beads of the beaded rows is identical in size such that the beaded rows form a square when the beaded rows are disposed on a furthermost edge of the frame.

Mathematical teaching apparatuses and methods of use are provided herein. In one embodiment a mathematical teaching apparatus includes a frame having a plurality of spaced apart rods, and an equal number of beads disposed on each of the plurality of spaced apart rods to create beaded rows. Each of the equal number of beads of the beaded rows is identical in size such that the beaded rows form a square when the beaded rows are disposed on a furthermost edge of the frame.

As disclosed herein a computer system for secure database backup and recovery in a secure database network has N distributed data nodes. The computer system includes program instructions that include instructions to receive a database backup file, fragment the file using a fragment engine, and associate each fragment with one node, where the fragment is not stored on the associated node. The program instructions further include instructions to encrypt each fragment using a first encryption key, and store, randomly, encrypted fragments on the distributed data nodes. The program instructions further include instructions to retrieve the encrypted fragments, decrypt the encrypted fragments using the first encryption key, re-encrypt the decrypted fragments using a different encryption key, and store, randomly, the re-encrypted fragments on the distributed data nodes. A computer program product and method corresponding to the above computer system are also disclosed herein.

As disclosed herein a computer system for secure database backup and recovery in a secure database network has N distributed data nodes. The computer system includes program instructions that include instructions to receive a database backup file, fragment the file using a fragment engine, and associate each fragment with one node, where the fragment is not stored on the associated node. The program instructions further include instructions to encrypt each fragment using a first encryption key, and store, randomly, encrypted fragments on the distributed data nodes. The program instructions further include instructions to retrieve the encrypted fragments, decrypt the encrypted fragments using the first encryption key, re-encrypt the decrypted fragments using a different encryption key, and store, randomly, the re-encrypted fragments on the distributed data nodes. A computer program product and method corresponding to the above computer system are also disclosed herein.

As disclosed herein a computer system for secure database backup and recovery in a secure database network has N distributed data nodes. The computer system includes program instructions that include instructions to receive a database backup file, fragment the file using a fragment engine, and associate each fragment with one node, where the fragment is not stored on the associated node. The program instructions further include instructions to encrypt each fragment using a first encryption key, and store, randomly, encrypted fragments on the distributed data nodes. The program instructions further include instructions to retrieve the encrypted fragments, decrypt the encrypted fragments using the first encryption key, re-encrypt the decrypted fragments using a different encryption key, and store, randomly, the re-encrypted fragments on the distributed data nodes. A computer program product and method corresponding to the above computer system are also disclosed herein.