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.

Radio communication system and method

Abstract: A mobile station determines, in accordance with reception quality of a radio signal from a base station, a measurement cycle of a predetermined measurement on a link status and/or on/off of the predetermined measurement and controls execution of the predetermined measurement based on the determination.

Ink jet printer having an eccentric head guide shaft for cleaning and sealing nozzle surface

Abstract: An ink jet printer is disclosed wherein an ink writing head is reprocably movably mounted on an eccentric guide shaft to scan a print line during print mode and moved to a cleaning position outside the print line during non-print mode. A nozzle cleaning device movably supports a liquid-absorbing cleaning tape along a path parallel to and adjacent to the nozzle surface. A drive system turns the guide shaft about the eccentric axis thereof and moves the cleaning tape during the non-print mode so that the nozzle surface moves in a substantially circular path to permit a section of the tape to provide a wiping action over the nozzle surface. A nozzle sealing device is arranged to make contact with the nozzle surface when the latter is moving in the circular path and held in pressure tight contact with the nozzle surface after the drive system is de-energized.

Operations management apparatus, operations management system, data processing method, and operations management program

Abstract: An operations management apparatus which acquires performance information for each of a plurality of performance items from a plurality of controlled units and manages operation of the controlled units includes a correlation model generation unit which derives a correlation function between a first element and a second element of the performance information, generates a correlation model between the first element and the second element based on the correlation function, and obtains the correlation model for each element pair of the performance information, and a model searching unit which searches for the correlation model for each element between an input element and an output element among elements of the performance information in series, and predicts a value of the output element from a value of the input element based on the searched correlation model.

Redundant virtual machine placement for fault-tolerant consolidated server clusters

Abstract: Consolidated server systems using server virtualization involves serious risks of host server failures that induce unexpected downs of all hosted virtual machines and applications. To protect applications requiring high-availability from unpredictable host server failures, redundant configuration using virtual machines can be an effective countermeasure. This paper presents a virtual machine placement method for establishing a redundant configuration against host server failures with less host servers. The proposed method estimates the requisite minimum number of virtual machines according to the performance requirements of application services and decides an optimum virtual machine placement so that minimum configurations survive at any k host server failures. The evaluation results clarify that the proposed method achieves requested fault-tolerance level with less number of hosting servers compared to the conventional N+M redundant configuration approach.

Method of purifying carbon nanotubes

Abstract: A mixture of carbon nanotubes and impurity carbon materials, which include carbon nanoparticles and may possibly include amorphous carbon, is purified into carbon nanotubes of high purity by utilizing a significant difference in oxidizability between the nanotubes and the nanoparticles. The mixture is pulverized and heated in the presence of an oxidizing agent at a temperature in the range from 600° to 1000° C. until the impurity carbon materials are oxidized and dissipated into gas phase. The nanotubes remain almost unoxidized except for loss of some lengths from the tube tips. It is suitable to perform the heating in air or oxygen.