ABSTRACT
A parallel computation method for large-size Fresnel computer-generated hologram (CGH) is reported. The method was introduced by us in an earlier report as a technique for calculating Fourier CGH from 2D object data. In this paper we extend the method to compute Fresnel CGH from 3D object data. The scale of the computation problem is also expanded to 2 gigapixels, making it closer to real application requirements. The significant feature of the reported method is its ability to avoid communication overhead and thereby fully utilize the computing power of parallel devices. The method exhibits three layers of parallelism that favor small to large scale parallel computing machines. Simulation and optical experiments were conducted to demonstrate the workability and to evaluate the efficiency of the proposed technique. A two-times improvement in computation speed has been achieved compared to the conventional method, on a 16-node cluster (one GPU per node) utilizing only one layer of parallelism. A 20-times improvement in computation speed has been estimated utilizing two layers of parallelism on a very large-scale parallel machine with 16 nodes, where each node has 16 GPUs.
ABSTRACT
A method has been proposed to reduce the communication overhead in computer-generated hologram (CGH) calculations on parallel and distributed computing devices. The method uses the shifting property of Fourier transform to decompose calculations, thereby avoiding data dependency and communication. This enables the full potential of parallel and distributed computing devices. The proposed method is verified by simulation and optical experiments and can achieve a 20 times speed improvement compared to conventional methods, while using large data sizes.
ABSTRACT
We herein report an unusual case of apocrine carcinoma on the forehead. The lesion was formed by the anastomosis of numerous tubular structures with widespread decapitation secretion, thus demonstrating apocrine differentiation. However, we observed some unusual histopathologic features that differed from those found in typical examples of apocrine ductal carcinoma, namely: 1) a relatively well-circumscribed lesion in the dermis, and 2) nodular or solid aggregations composed of basaloid cells. We believe the present case is an apocrine ductal carcinoma, although it has a nodular appearance and basaloid cells. Otherwise, it could be a hitherto undescribed variant of apocrine carcinoma. This apocrine carcinoma on the forehead may have originated from either pluripotential cells or from apocrine glands at an unusual site.
