Showing papers by "Mitsubishi Electric published in 2008"

The Solar Optical Telescope for the Hinode Mission: An Overview

Abstract: The Solar Optical Telescope (SOT) aboard the Hinode satellite (formerly called Solar-B) consists of the Optical Telescope Assembly (OTA) and the Focal Plane Package (FPP). The OTA is a 50-cm diffraction-limited Gregorian telescope, and the FPP includes the narrowband filtergraph (NFI) and the broadband filtergraph (BFI), plus the Stokes Spectro-Polarimeter (SP). The SOT provides unprecedented high-resolution photometric and vector magnetic images of the photosphere and chromosphere with a very stable point spread function and is equipped with an image-stabilization system with performance better than 0.01 arcsec rms. Together with the other two instruments on Hinode (the X-Ray Telescope (XRT) and the EUV Imaging Spectrometer (EIS)), the SOT is poised to address many fundamental questions about solar magnetohydrodynamics. This paper provides an overview; the details of the instrument are presented in a series of companion papers.

Image Stabilization System for Hinode (Solar-B) Solar Optical Telescope

Abstract: The Hinode Solar Optical Telescope (SOT) is the first space-borne visible-light telescope that enables us to observe magnetic-field dynamics in the solar lower atmosphere with 0.2 – 0.3 arcsec spatial resolution under extremely stable (seeing-free) conditions. To achieve precise measurements of the polarization with diffraction-limited images, stable pointing of the telescope (<0.09 arcsec, 3σ) is required for solar images exposed on the focal plane CCD detectors. SOT has an image stabilization system that uses image displacements calculated from correlation tracking of solar granules to control a piezo-driven tip-tilt mirror. The system minimizes the motions of images for frequencies lower than 14 Hz while the satellite and telescope structural design damps microvibration in higher frequency ranges. It has been confirmed from the data taken on orbit that the remaining jitter is less than 0.03 arcsec (3σ) on the Sun. This excellent performance makes a major contribution to successful precise polarimetric measurements with 0.2 – 0.3 arcsec resolution.

Homomorphic Encryption and Signatures from Vector Decomposition

Abstract: This paper introduces a new concept, distortion eigenvector space; it is a (higher dimensional) vector space in which bilinear pairings and distortion maps are available. A distortion eigenvector space can be efficiently realized on a supersingular hyperelliptic curve or a direct product of supersingular elliptic curves. We also introduce an intractable problem (with trapdoor) on distortion eigenvector spaces, the higher dimensional generalization of the vector decomposition problem (VDP). We define several computational and decisional problems regarding VDP, and clarify the relations among them. A trapdoor bijective functionwith algebraically rich properties can be obtained from the VDP on distortion eigenvector spaces. This paper presents two applications of this trapdoor bijective function; one is multivariate homomorphic encryption as well as a two-party protocol to securely evaluate 2DNF formulas in a higher dimensional manner, and the other is various types of signatures such as ordinary signatures, blind signatures, generically (selectively and universally) convertible undeniable signatures and their combination.

Robust abandoned object detection using dual foregrounds

Abstract: As an alternative to the tracking-based approaches that heavily depend on accurate detection of moving objects, which often fail for crowded scenarios, we present a pixelwise method that employs dual foregrounds to extract temporally static image regions. Depending on the application, these regions indicate objects that do not constitute the original background but were brought into the scene at a subsequent time, such as abandoned and removed items, illegally parked vehicles. We construct separate long- and short-term backgrounds that are implemented as pixelwise multivariate Gaussian models. Background parameters are adapted online using a Bayesian update mechanism imposed at different learning rates. By comparing each frame with these models, we estimate two foregrounds. We infer an evidence score at each pixel by applying a set of hypotheses on the foreground responses, and then aggregate the evidence in time to provide temporal consistency. Unlike optical flow-based approaches that smear boundaries, our method can accurately segment out objects even if they are fully occluded. It does not require on-site training to compensate for particular imaging conditions. While having a low-computational load, it readily lends itself to parallelization if further speed improvement is necessary.

Calibration method, communication system, frequency control method, and communication device

Abstract: A calibration method according to the present invention includes a step of first channel estimating for transmitting a pilot signal from a first antenna and receiving the pilot signal at a second antenna different from the first antenna to calculate a first channel estimation value; a step of second channel estimating for transmitting a plot signal from the second antenna and receiving the pilot signal at the first antenna to calculate a second channel estimation value; and a step of correction coefficient calculating for calculating, by using the first and second channel estimation values, a correction coefficient.

Probabilistic latent variable models as nonnegative factorizations.

Abstract: This paper presents a family of probabilistic latent variable models that can be used for analysis of nonnegative data. We show that there are strong ties between nonnegative matrix factorization and this family, and provide some straightforward extensions which can help in dealing with shift invariances, higher-order decompositions and sparsity constraints. We argue through these extensions that the use of this approach allows for rapid development of complex statistical models for analyzing nonnegative data.

Charged particle beam irradiation apparatus

Abstract: In a charged particle beam irradiation apparatus to be adapted to a particle beam cancer treatment system or the like, a desired depth dose distribution is highly precisely created. In the charged particle beam irradiation apparatus that irradiates a particle beam, which is radiated from a particle beam generation unit, to a subject to be irradiated via a ridge filter exhibiting a cyclic thickness distribution for causing the particle beam to exhibit a desired energy distribution, the ridge filter has plural ridges thereof arranged to be perpendicular to entering directions of the particle beam.

Fast Measurement Technique for Phased Array Calibration

Abstract: A novel measurement method is proposed in order to measure the active electric fields of the individual antenna elements in a phased array antenna. Fast and accurate measurements can be realized by the proposed method because the electric fields of multiple elements can be obtained simultaneously and no phase measurements are required. Hence, it can be easily applied to the on-board diagnostics and re-calibration in the operating phased array antenna systems. In the first step with this method, the phases of multiple antenna elements are successively shifted with the specified phase intervals while the array power variations are measured. Next, the measured power variation is expanded into a Fourier series and the terms are rearranged to put them into the form of the rotating element electric field vector (REV) method. Finally, the REV solution is used to identify the electric fields of the individual elements. Additionally, a theoretical study is carried out on the accuracy of the proposed measurement method. Simple, closed-form equations have been successfully derived for the measurement errors and the calibration accuracy is theoretically estimated. The proposed measurement method is validated with experimental results and the measurement accuracy is compared with the theoretical prediction.

Semiconductor device and shift register circuit

Abstract: A dual-gate transistor formed of two transistors connected in series between a first power terminal and a first node is used as a charging circuit for charging a gate node (first node) of a transistor intended to pull up an output terminal of a unit shift register. The dual-gate transistor is configured such that the connection node (second node) between the two transistors constituting the dual-gate transistor is pulled down to the L level by the capacitive coupling between the gate and second node in accordance with the change of the gate from the H level to the L level.

Heat pump water heater

Abstract: A heat pump water heater includes: a compressor; a first water-refrigerant heat exchanger; a second water-refrigerant heat exchanger; refrigerant paths capable of forming a refrigerant circuit; and water channels including a flow channel, the flow channel leading hot water that has passed through the second water-refrigerant heat exchanger to the first water-refrigerant heat exchanger The heat pump water heater is able to perform a heating operation In the heating operation, the hot water heated in the second water-refrigerant heat exchanger is fed to the first water-refrigerant heat exchanger and the hot water further heated in the first water-refrigerant heat exchanger is supplied to a downstream side of the water channels The first water-refrigerant heat exchanger is able to be replaced without replacing the second water-refrigerant heat exchanger

Regularized non-negative matrix factorization with temporal dependencies for speech denoising

Abstract: We present a technique for denoising speech using temporally regularized nonnegative matrix factorization (NMF). In previous work [1], we used a regularized NMF update to impose structure within each audio frame. In this paper, we add frame-to-frame regularization across time and show that this additional regularization can also improve our speech denoising results. We evaluate our algorithm on a range of nonstationary noise types and outperform a state-of-the-art Wiener filter implementation. Interspeech 2008

Integer Variable Χ---Based Ate Pairing

Abstract: In implementing an efficient pairing calculation, it is saidthat the lower bound of the number of iterations of Miller'salgorithm is log2r/φ(k),where φ(·) is the Euler's function. Ate pairingreduced the number of the loops of Miller's algorithm of Tatepairing from $\lfloor\log_2r\rfloor$ to $\lfloor\log_2(t-1)\rfloor$. Recently, it is known to systematicallyprepare a pairing---friendly elliptic curve whose parameters aregiven by a polynomial of integer variable "Χ". For thecurve, this paper gives integer variable Χ---basedAte pairing that achieves the lower bound byreducing it to $\lfloor\log_2\chi\rfloor$.

Security proof for quantum-key-distribution systems with threshold detectors

Abstract: In this paper, we rigorously prove the intuition that in security proofs for the Bennett-Brassard 1984 (BB84) protocol, one may regard an incoming signal to Bob as a qubit state. From this result, it follows that all security proofs for BB84 protocol based on a virtual qubit entanglement distillation protocol, which was originally proposed by Lo and Chau [Science 283, 2050 (1999)] and by Shor and Preskill [Phys. Rev. Lett. 85, 441 (2000)], are all valid even if Bob's actual apparatus cannot distill a qubit state explicitly. As a consequence, especially, the well-known result that a higher bit error rate of 20% can be tolerated for BB84 protocol by using two-way classical communications is still valid even when Bob uses threshold detectors. Using the same technique, we also prove the security of Bennett-Brassard-Mermin 1992 (BBM92) protocol where Alice and Bob both use threshold detectors.

Mobile communication system, base station, mobile station, and base station installation method

Abstract: Provided is a mobile communication system which eliminates a non-sensitive region and in which a mobile station can stably communicate with a base station. Moreover, the mobile communication system can reduce the handover failure ratio and the number of the handovers. In the mobile communication system, if quality information on the acquired data relates to data from a base station A, the mobile station (11) reports it to the base station A; and if the quality information relates to data from a base station B, the mobile station (11) reports it to the base station B. The base stations A and B report the quality information received from the mobile station (11) as history information on the mobile station (11) to a base station upper node device (14). The base station upper node device (14) compares the quality information received from the two base stations. The base station upper node device (14) selects the base station which has sent better quality and instructs the base station to communicate with the mobile station (11). The base station upper node device (14) instructs the other base station not to communicate with the mobile station (11).

Manipulation input device

Abstract: When a vehicle navigation system is manipulated by taking pictures of a user hand motion and gesture with a camera, as the number of apparatuses and operational objects increases, the associated hand shapes and hand motions increase, thus causing a complex manipulation for a user. Furthermore, in detecting a hand with the camera, when the image of a face having color tone information similar to that of a hand appears in an image taken with a camera, or outside light rays such as sun rays or illumination rays vary, detection accuracy is reduced. To overcome such problems, a manipulation input device is provided that includes a limited hand manipulation determination unit and a menu representation unit, whereby a simple manipulation can be achieved and manipulation can accurately be determined. In addition, detection accuracy can be improved by a unit that selects a single result from results determined by a plurality of determination units, based on images taken with a plurality of cameras.

Image display apparatus

Abstract: An image display apparatus is for correcting an input image signal and displaying an image on a display unit based on the corrected image signal, and includes: an illuminance detector for sequentially detecting illuminance values around the apparatus; an illuminance analyzer for sequentially outputting image settings for correction of the image signal depending on the detected illuminance values; a setting selector for outputting an image setting which has been output from the analyzer a number of times greater than a number of times any other image setting has been output, or an image setting determined by the statistic of the image settings output from the analyzer; and a setting application unit for changing the image setting used to correct the image signal to be equal to the image setting output from the selector, when a predetermined change occurs in the input image signal or when a predetermined time has come.

Measurement apparatus, measurement method, and feature identification apparatus

Abstract: It is an object to measure a position of a feature around a road. An image memory unit stores images in which neighborhood of the road is captured. Further, a three-dimensional point cloud model memory unit 709 stores a point cloud showing three-dimensional coordinates obtained by laser measurement which is carried out simultaneously to the image-capturing of the images as a road surface shape model. A model projecting unit 172 projects a point cloud on the image, and an image displaying unit 341 displays the point cloud superimposed with the image on the displaying device. Using an image point inputting unit 342, a pixel on a feature of a measurement target is specified by a user as a measurement image point. A neighborhood extracting unit 171 extracts a point which is located adjacent to the measurement image point and superimposed on the feature for the measurement target from the point cloud. A feature position calculating unit 174 outputs three-dimensional coordinates shown by the extracted point as three-dimensional coordinates of the feature for the measurement target.

Electric power steering control apparatus

Abstract: An electric power steering control apparatus can reduce a steering vibration such as shimmy vibration generated due to the structure of a vehicle without adding new mechanism elements. The apparatus includes a torque sensor for detecting steering torque generated by a driver, a torque controller for calculating an assist torque current for assisting the steering torque based on the detected steering torque, a vehicle speed detector for detecting the speed of the vehicle, a specific frequency detector for detecting a specific frequency from the detected vehicle speed, a motor angular velocity calculator for calculating a motor angular velocity from a motor angle detected by an angle detector, a phase compensator for converting a vibration frequency of the motor angular velocity, and a vibration suppression current calculator for calculating a vibration suppression current to suppress the steering vibration from respective output signals of the phase compensator and the specific frequency detector.

Remarkable Increase in the Channel Mobility of SiC-MOSFETs by Controlling the Interfacial $\hbox{SiO}_{2}$ Layer Between $\hbox{Al}_{2}\hbox{O}_{3}$ and SiC

Abstract: The impact of a thin SiO2 layer inserted between Al2O3 and SiC on channel mobility in AI2O3/SiC MOSFETs was investigated. The remarkable increase in the channel mobility is demonstrated when the SiO2 thickness is around 1 nm. The thin SiO2 layer is formed by the thermal oxidation of the SiC substrate at 600 or 800degC in O2 atmosphere. The peak value of the field-effect mobility in AI2O3/SiO2/SiC MOSFETs is as high as 300 cm2 / (V ldr s). On the other hand, when the SiO2 layer is 2.0 nm, the field-effect mobility drastically reduces to 40 cm2/ (V ldr s), which is most likely due to the high interface trap density as seen in conventional SiO2/SiC MOSFETs.

Gate drive apparatus

Abstract: A gate drive apparatus including a constant-current-pulse gate drive circuit which creates a gate signal for a switching device as a constant-current output, a constant-voltage-pulse gate drive circuit which creates the gate signal as a constant-voltage output, and a decision/switch circuit which switches the operation of the constant-current-pulse gate drive circuit and the operation of the constant-voltage-pulse gate drive circuit. The variance of switching speeds attributed to the variances of threshold voltages and mirror voltages in a plurality of switching devices which are driven by the gate drive apparatus can be suppressed, and the variance of losses can be minimized.

Positioning system, air conditioning system and lighting system

Abstract: To provide a positioning system that clearly defines a disposition of a base station for identifying a position of a radio set. While a wireless base station 1 that transmits and receives a distance-measuring signal to and from a terminal 2 to be measured by wireless communication is disposed at each corner forming an equilateral triangular, the length of each side of the equilateral triangle is made to be a maximum communication distance of the wireless base station 1.

Optical fiber sensor

Abstract: An optical fiber sensor measuring refractive index of a medium with high sensitivity in a wide range. The optical fiber sensor includes an optical fiber causing a transmission loss due to leakage in the clad propagation mode from a portion of a core and a clad where a Bragg grating is provided, a light source permitting light in a wavelength band in the clad propagation mode to enter the optical fiber, and a light-receiving section receiving the transmitted or reflected light transmitted through the core and the clad at the portion where the Bragg grating is provided. The refractive index of the medium to be measured in contact with the clad is measured according to total intensity of the light received by the light-receiving section. The Bragg grating is inclined at a predetermined angle of inclination to the vertical line vertical to the length direction of the optical fiber.

Heat conductive sheet and power module

Abstract: The present invention is a thermal conductive sheet characterized by comprising secondary particles composed of boron nitride primary particles and matrix resin, wherein the secondary particles are deformed and the deformed secondary particles surface contact each other. The ratio of the matrix resin that exists between the secondary particles in this thermal conductive sheet is preferably 5 volume%-50 volume%. This thermal conductive sheet has advantages in productivity and cost, and has excellent thermal conductivity in a sheet thickness direction and electric insulation.

Nitride semiconductor device

Abstract: A nitride semiconductor device with a p electrode having no resistance between itself and other electrodes, and a method of manufacturing the same are provided. A p electrode is formed of a first Pd film, a Ta film, and a second Pd film, and on a p-type contact layer of a nitride semiconductor. On the second Pd film, a pad electrode is formed. The second Pd film is formed on the entire upper surface of the Ta film which forms part of the p electrode, and serves as an antioxidant film that prevents oxidation of the Ta film. Preventing oxidation of the Ta film, the second Pd film can reduce the resistance that may exist between the p electrode and the pad electrode, thereby preventing a failure in contact between the p electrode and the pad electrode and providing the p electrode with low resistance.

Next Generation FEC for Optical Communication

Abstract: Forward Error Correction - Brief Explanation -Terminologies Net Coding Gain History of Forward Error Correction

Image encoder and image decoder

Abstract: An encoding method and so forth for encoding a moving image signal containing color components involving the same sampling ratio with an enhanced optimality An image encoder comprises a color component separating section for individually separating the color components of an input bit stream, a block dividing section for dividing the input color component signal into blocks having a size determined by encoding block size specifying information and generating a signal in an encoding unit region, a prediction image creating section for creating a prediction image for the signal in the encoding unit region correspondingly to one or more prediction modes which specify prediction image creating methods, a determining section for determining the prediction mode used for the encoding according to the prediction efficiency of the prediction image outputted from the prediction image creating section, a prediction error encoding section for encoding the difference between the prediction image corresponding to the determined prediction mode and the input color component signal, and an encoding section for carrying out variable length encoding of the prediction mode, the output of the prediction error encoding section, and a color component identification flag indicating which color component the bit stream belongs to by the color component separation

Communication method, base station, communication system, mobile terminal

Abstract: In accordance with the present invention, in a case of using persistent scheduling, when detecting a transition from a talk state to a silent state, resources to be allocated during a silent state are allocated to a channel exclusive for silent period, and the resources which have been allocated to a mobile terminal during the talk spurt are released. Therefore, the useless allocation of resources can be reduced, and the throughput of the system can be improved.

On-vehicle communication device

Abstract: An on-vehicle communication device capable of suppressing a delay in providing information, avoiding congestion, and sufficiently securing transmission power, includes a communication controller to controls a transmission cycle and transmission power when data is transmitted from a transmitting/receiving device. The communication controller uses its own vehicle information and surrounding vehicle information to estimate a degree of risk and a safe distance of its own vehicle. The communication controller controls the transmission cycle of its own vehicle based on a communication channel utilization rate of its own vehicle, a communication channel utilization rate of a surrounding vehicle and the degree of risk of its own vehicle, and controls the transmission power of its own vehicle based on the communication channel utilization rate of its own vehicle, the communication channel utilization rate of the surrounding vehicle and the safe distance.

Automotive supercharging apparatus

Abstract: An electric motor-generator and an engine are linked using a first belt that is looped around a crank pulley that is mounted to a crank shaft and a one-way clutch pulley that is mounted to a rotating shaft. An electronic control unit drives the electric motor-generator as an electric motor and drives the compressor by the electric motor-generator if engine speed is less than or equal to a predetermined value.