Magic cube

Abstract: Two detectors for fast two-dimensional (2D) and quasi-three-dimensional (quasi-3D) verification of the dose delivered by radiotherapy beams have been developed at University and Istituto Nazionale di Fisica Nucleare (INFN) of Torino. The Magic Cube is a stack of strip-segmented ionization chambers interleaved with water-equivalent slabs. The parallel plate ionization chambers have a sensitive area of 24 x 24 cm2, and consist of 0.375 cm wide and 24 cm long strips. There are a total of 64 strips per chamber. The Magic Cube has been tested with the clinical proton beam at Loma Linda University Medical Centre (LLUMC), and was shown to be capable of fast and precise quasi-3D dose verification. The Pixel Ionization Chamber (PXC) is a detector with pixel anode segmentation. It is a 32 x 32 matrix of 1024 cylindrical ionization cells arranged in a square 24 x 24 cm2 area. Each cell has 0.4 cm diameter and 0.55 cm height, at a pitch of 0.75 cm separates the centre of adjacent cells. The sensitive volume of each single ionization cell is 0.07 cm3. The detectors are read out using custom designed front-end microelectronics and a personal computer-based data acquisition system. The PXC has been used to verify dynamic intensity-modulated radiotherapy for head-and-neck and breast cancers.

Abstract: Permutation-only image ciphers encrypt images by permuting the positions of all pixels in a secret way, which are unfortunately frail under known-text attack. In view of the weakness of permutation-only algorithms, a color image encryption algorithm based on magic cube transformation and a new modular arithmetic operation is designed. First, a natural number chaotic sequence is created with the secret key. For the sake of higher security, all secret keys are generated by different chaotic maps, and thus increase the security for decryption. Second, we implement the position permutation algorithm by magic cube transformation with chaotic sequences. Third, the pixel-substitution algorithm is realized by changing the image pixel value, with a XOR plus mod diffuse operation and a modular arithmetic operation. Finally, experimental results are given to demonstrate the efficiency and high security of our novel algorithm.

Abstract: Permutation-only image ciphers encrypt images by permuting the positions of all pixels in a secret way, which are unfortunately frail under known-text attack. In view of the weakness of permutation-only algorithms, a color image encryption algorithm based on magic cube transformation and a new modular arithmetic operation is designed. First, a natural number chaotic sequence is created with the secret key. For the sake of higher security, all secret keys are generated by different chaotic maps, and thus increase the security for decryption. Second, we implement the position permutation algorithm by magic cube transformation with chaotic sequences. Third, the pixel-substitution algorithm is realized by changing the image pixel value, with a XOR plus mod diffuse operation and a modular arithmetic operation. Finally, experimental results are given to demonstrate the efficiency and high security of our novel algorithm.

Abstract: We propose a deployable quasi-Yagi monopole antenna using origami magic spiral cubes, constructed from low-cost paper substrate. The proposed quasi-Yagi antenna consists of an L-shaped driven monopole, an L-shaped reflector, and two L-shaped directors. These driven monopole, reflector, and directors are designed in L-shaped geometries to achieve maximum gain in a limited cube size. The driven element and reflector are realized on the origami magic cube #1, while the two directors are designed on the magic cubes #2 and #3, respectively. The cubes are stacked together using a thin adhesive film. The presented geometry of the origami magic spiral cube antenna can be easily folded and unfolded. The dimensions in the unfolded state are 44 mm × 44 mm × 132 mm while the dimensions in the folded state are 44 mm × 44 mm × 8 mm. Therefore, in the folded state, the antenna occupies only 6% of the unfolded volume. We have numerically analyzed the antenna performance and verified the outcomes experimentally. The L-shaped reflector has increased the monopole antenna gain from 1.9 to 5.7 dBi. With the addition of two directors, the gain is further increased to 7.3 dBi at 1.9 GHz.