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.

Metal plate for preventing radiowave leakage through an aperture in a waveguide body

Abstract: A waveguide circuit is provided, in which fixing a metal cover to a waveguide body with screws can prevent radiowave leakage suitably without any application of the conductive adhesive, solder and braze as a material for the radiowave leakage prevention. A metal plate is provided at the end of an aperture of a waveguide body in a radiowave traveling direction and overlaps with the end of a metal cover.

Global scheduling independent of control dependencies based on condition vectors

Abstract: The authors present a global scheduling method based on condition vectors. The proposed method exploits global parallelism. The technique can schedule operations independent of control dependencies. It transforms the control structure of the given behavior drastically, while preserving semantics to minimize the number of states in final schedule. The method can parallelize multiple nests of conditional branches and optimize across the boundaries of basic blocks. It can also optimize all possible execution paths. An algorithm is proposed which generates a single finite state machine controller from parallel individual control sequences derived in the global parallelization process. Experimental results prove that the global parallelization is very effective. >

System and method for transmitting entertainment information to authorized ones of plural receivers

Abstract: An audiovisual subscription system includes means for aperiodically inverting the lines of a transmitted video signal on a frame-by-frame basis and for decrypting encrypted PCM audio information which is transmitted along with the aperiodically inverted video information.

Flash memory incorporating microcomputer having on-board writing function

Abstract: In a microcomputer comprising internal buses (AB, DB) , a serial communication interface (2), a flash memory (4) , a RAM (5), a ROM (6) for storing a writing program, an input/output port (1b), a CPU (7), and a mode control unit (3) for setting various operation modes and test modes in the microcomputer, a switching circuit (8) is connected between the ROM and the internal buses and between the input/output port and the internal buses. The mode control unit operates the switching circuit in an emulation test mode so that the ROM is deactivated and the input/output port is activated. Then, the CPU reads a program from the serial communication interface and writes the program into the flash memory in accordance with a writing program from the input/output port.

t-DCF: a Detection Cost Function for the Tandem Assessment of Spoofing Countermeasures and Automatic Speaker Verification

Abstract: The ASVspoof challenge series was born to spearhead research in anti-spoofing for automatic speaker verification (ASV). The two challenge editions in 2015 and 2017 involved the assessment of spoofing countermeasures (CMs) in isolation from ASV using an equal error rate (EER) metric. While a strategic approach to assessment at the time, it has certain shortcomings. First, the CM EER is not necessarily a reliable predic-tor of performance when ASV and CMs are combined. Second, the EER operating point is ill-suited to user authentication applications , e.g. telephone banking, characterised by a high target user prior but a low spoofing attack prior. We aim to migrate from CM-to ASV-centric assessment with the aid of a new tandem detection cost function (t-DCF) metric. It extends the conventional DCF used in ASV research to scenarios involving spoofing attacks. The t-DCF metric has 6 parameters: (i) false alarm and miss costs for both systems, and (ii) prior probabilities of target and spoof trials (with an implied third, nontar-get prior). The study is intended to serve as a self-contained, tutorial-like presentation. We analyse with the t-DCF a selection of top-performing CM submissions to the 2015 and 2017 editions of ASVspoof, with a focus on the spoofing attack prior. Whereas there is little to choose between countermeasure systems for lower priors, system rankings derived with the EER and t-DCF show differences for higher priors. We observe some ranking changes. Findings support the adoption of the DCF-based metric into the roadmap for future ASVspoof challenges, and possibly for other biometric anti-spoofing evaluations.