NEC

About: NEC is a company organization based out in Tokyo, Japan. It is known for research contribution in the topics: Signal & Layer (electronics). The organization has 33269 authors who have published 57670 publications receiving 835952 citations. The organization is also known as: NEC Corporation & NEC Electronics Corporation.

High-Speed Quantum Key Distribution System for 1-Mbps Real-Time Key Generation

Abstract: A high-speed quantum key distribution (QKD) system has been developed with the goal of a 1-Mbps final secure key generation rate under 10-dB transmission loss, which corresponds to 50 km of standard single mode fiber. For the purpose of speeding-up all processes in QKD sequence, we apply a wavelength-division-multiplexing (WDM) technique using the colorless interferometric technique and a key distillation hardware (HW) engine. We establish a novel WDM scheme, sharing interferometers and their temperature regulators over multiple channels, which enables us to increase the number of channels with a small impact on system cost and size. To generate a secure key while satisfying both high speed and high security, we develop a key distillation HW engine which enables us to execute key distillation with 1-Mbit code length in real time. We have experimentally evaluated the performance of the developed system through installed fiber. By operating three wavelength channels, a new, world leading key generation rate of greater than 200 kbps over a 14.5-dB transmission loss has been achieved.

Fingerprint identification method and apparatus

Abstract: A method and device for fingerprint identification implementing precise identification at a high speed by using partial images of a fingerprint obtained through relative movements of a finger to a small sized sensor are provided. For reassembling a sequence of partial images inputted from a frame input section 50 into a complete image, each of the partial images is collated with a user's fingerprint image (template image) registered in a template image storage section 52 to determine a position where the partial image matches best at an optimal position calculator 55, and then combined with a partial composite image stored in a partial composite image storage section 53 at an image combining section 60. When the complete composite image is obtained after repeating the above operations, specific features are extracted from the composite image at a reference character extracting section 62, and collated with those of the template image stored in a template reference character storage section 54. Consequently, user authentication can be performed at a high speed while ensuring stability in the collating operation.

Isotope effect on superconductivity in Rb3C60

Abstract: THE surprisingly high transition temperatures (Tc) for superconductivity in alkali-meta-doped C60 has spurred wide interest in understanding its mechanism1–6. Recently the increase in Tc with lattice constant was demonstrated for these materials6, and was interpreted as resulting from the corresponding increase in the density of states at the Fermi level. According to the standard (BCS) theory of superconductivity, the other important factor controlling Tc is the phonon that mediates electron pairing. To test whether this factor plays a part for the C60 superconductors, we prepared C60 containing various amounts of 13C, which we then doped with rubidium to give Rb3C60. Measurements of diamagnetic shielding and Meissner effect show that Tc decreases as the 13C content increases, as expected within the context of BCS-like phonon-mediated pairing; but the dependence on the mass is stronger than for most electron-phonon superconductors where Tcm−α with α ≤0.5. Instead, the exponent a has the remarkably large value of 1.4±0.5. Regardless of the interpretation of this value, it is clear that phonons have an important role in the origin of superconductivity in doped C60.

Data transfer control system between high speed main memory and input/output processor with a data mover

Abstract: In a data processing method of this invention, data having an amount of a designated total data transfer length is transferred from a data buffer in a data mover to a designated start address of a control memory at a data transfer rate of a control data transfer control unit. Data having an amount of a designated block data transfer length is transferred from the buffer in the data mover to a designated start address of a high-speed arithmetic memory at a data transfer rate of a high-speed data transfer control unit.

Memory access controller

Abstract: In order to write data flowing in continuously into an image memory consisting of a single port RAM without lack and to read data out of the image memory continuously without lack in parallel, a memory access processor of the invention comprises; a write buffer for storing temporarily data flowing in continuously and outputting write requests while data are stored therein, a read buffer for storing temporarily data output from the image memory to be read out therefrom continuously, and an arbiter section for arbitrating concurrence between write requests and read requests for the image memory, writing data stored in the write buffer at a speed higher than a speed of data writing into the write buffer when write actions are performed according to the write requests, and reading data out of the image memory to be stored in the read buffer at a speed higher than a speed of data readout from the read buffer when read actions are performed according to the read requests.