Showing papers by "Mitsubishi Electric published in 2006"

Impact of Matching Network on Bandwidth of Compact Antenna Arrays

Abstract: We analyze the impact of the matching network on compact multiple-input multiple-output systems. Existing studies have found that the matching network has a significant influence on the performance of multiple antenna systems when the antennas are in close proximity. However, none has examined the wide-band case. In this paper, we investigate the wide-band performance of four different matching networks for multiple dipole antennas. The performance of the matching networks is given in terms of the bandwidths of correlation and matching efficiency, which are extensions of the single-antenna concept of bandwidth to multiple antenna systems. We also investigate the impact of the propagation conditions on the matching and bandwidth. For a uniform two-dimensional (2-D) angular power spectrum, we find that while individual-port matching can achieve in excess of 3% fractional correlation bandwidth for envelope correlation of 0.5 at an antenna separation of 0.01lambda, multiport matching is required for efficiency bandwidth to exist for a return loss of -6 dB. Moreover, even with multiport matching, both correlation and efficiency bandwidths decrease drastically at small antenna separations. At 0.01lambda, the correlation and efficiency bandwidths are 0.4% and 0.2%, respectively. Similar evaluations were performed for measured outdoor-to-indoor channels with moderate to small 2-D angular spreads. We find that the efficiency advantage of multiport matching over individual-port matching diminishes with decreasing angular spread

Security evaluation of DPA countermeasures using dual-rail pre-charge logic style

Abstract: In recent years, some countermeasures against Differential Power Analysis (DPA) at the logic level have been proposed. At CHES 2005 conference, Popp and Mangard proposed a new countermeasure named Masked Dual-Rail Pre-Charge Logic (MDPL) which combine dual-rail circuits with random masking to improve Wave Dynamic Differential Logic (WDDL). The proposers of MDPL claim that it can implement secure circuits using a standard CMOS cell library without special constraints for the place-and-route because the difference of loading capacitance between all pairs of complementary logic gates in MDPL can be covered up by the random masking. In this paper, we especially focus the signal transition of the MDPL gate and evaluate the DPA-resistance of MDPL in detail. Our evaluation results show that the leakage occurs in the MDPL gates as well as WDDL gates when input signals have difference of delay time even if MDPL has an effectiveness on reducing the leakage caused by the difference of loading capacitance. Furthermore, we demonstrate the problem with different input signal delays by measurements of an FPGA and show the validity of our evaluation.

Data communication method, communication system and mobile terminal

Abstract: In a communications system which complies with LTE including a base station 2 which transmits data by using an OFDM (Orthogonal Frequency Division Multiplexing) method as a downlink access method, and a mobile terminal 3, in a case in which an uplink scheduling request signal SR is transmitted by using an S-RACH when an Ack/Nack signal is being transmitted by using an Ack/Nack exclusive channel, the transmission of the Ack/Nack signal is stopped while the uplink scheduling request signal SR is transmitted.

Method and system for processing multiview videos for view synthesis using side information

Abstract: A method processes a multiview videos of a scene, in which each video is acquired by a corresponding camera arranged at a particular pose, and in which a view of each camera overlaps with the view of at least one other camera. Side information for synthesizing a particular view of the multiview video is obtained in either an encoder or decoder. A synthesized multiview video is synthesized from the of multiview videos and the side information. A reference picture list is maintained for each current frame of each of the multiview videos, the reference picture indexes temporal reference pictures and spatial reference pictures of the acquired multiview videos and the synthesized reference pictures of the synthesized multiview video. Each current frame of the multiview videos is predicted according to reference pictures indexed by the associated reference picture list.

Application of functionally graded material for solid insulator in gaseous insulation system

Abstract: Functionally graded materials (FGM) have spatial distribution of a material property in order to achieve efficient stress control. An application of the FGM to a solid insulator (spacer) for a gaseous insulation system, like gas insulated switchgear, is expected to improve electric field (E-field) distribution around the spacer. In this paper, we describe the applicability of the FGM spacer to gas insulated power equipment. In the FGM spacer, we gave spatial distribution of dielectric permittivity to control the E-field distribution inside and outside the spacer. This paper includes following key results for the applications of the FGM. Firstly, E-field simulation results when applying the FGM by a finite element method are presented, in which we show the effective reduction of the maximum field strength by applying the FGM. Next, a fabrication technique of the FGM spacer sample with not only step-by-step but also continuous changes of permittivity is presented by use of centrifugal force. Finally, dielectric breakdown tests using FGM samples which are accurately controlled the spatial distribution of permittivity are carried out under lightning impulse voltage applications. The test result indicates the increase of breakdown voltage (BDV). From these results, we verified the applicability and the fabrication technique of FGM spacer for improvement of the dielectric strength in the gaseous insulation system.

Method and apparatus for video navigation

Abstract: A method of deriving a representation of a video sequence comprises deriving metadata expressing at least one temporal characteristic of a frame or group of frames, and one or both of metadata expressing at least one content-based characteristic of a frame or group of frames and relational metadata expressing relationships between at least one content-based characteristic of a frame or group of frames and at least one other frame or group of frames, and associating said metadata and/or relational metadata with the respective frame or group of frames.

NRZ-OOK-to-RZ-BPSK modulation-format conversion using SOA-MZI wavelength converter

Abstract: A novel all-optical modulation-format conversion from nonreturn-to-zero on-off keying (NRZ-OOK) to return-to-zero binary phase-shift keying (RZ-BPSK) is proposed. A Mach-Zehnder interferometric (MZI) wavelength converter consisting of integrated semiconductor optical amplifiers (SOAs) is utilized to implement the proposed format conversion. Error-free operation at a bit rate of 10.7 Gb/s is experimentally demonstrated in order to show the feasibility of the proposed scheme. The received sensitivity of the converted signal is improved by 2.9 dB compared with a back-to-back NRZ-OOK signal at BER=10 -9. In addition, a reasonable dispersion tolerance of the converted signal up to plusmn500 ps/nm is observed. The numerical simulation based upon the carrier-rate equation verifies the experimental results

Air-conditioning system

Abstract: An air-conditioning system capable of reducing traffic of signals and effectively performing control and management operations without causing heavy traffic is obtained. In an air-conditioning system including one or more indoor units 200 , one or more outdoor units 100 , and a centralized control apparatus 300 and performing signal communication, a transmission relay 400 is provided between a first transmission line 500 to which the one or more outdoor units 100 and the centralized control apparatus 300 are connected and a second transmission line 510 to which one or more indoor units 200 constituting a group are connected, the transmission relay 400 relays a signal between the first transmission line 500 and the connected second transmission line 510 . The transmission relay 400 further includes arithmetic processing means 430 for processing data included in the signal transmitted via the connected second transmission line 510 , and data storage means 440 for storing data regarding the processing by the arithmetic processing means 430.

Surface light source device and display device using the same

Abstract: A surface light source device according to the invention includes a housing having an opening portion on at least one face, an LED light source held by one face of the housing opposing the opening portion, and a light guiding plate arranged at a position so as to cover the opening portion and the LED light source, wherein the light guiding plate includes a recess provided at a position corresponding to the LED light source for storing a part of the LED light source, and light quantity adjusting means provided at a bottom part of the recess for adjusting light from the LED light source, and the light quantity adjusting means includes a reflection sheet having a reflection function and a transmission function in which a total light transmittance t satisfies t≧πr 2 cos θ/{(1−cos θ)(S−πr 2 )}, supposing that an average radius is defined as r, a distance from the LED light source is defined as H, a light-emitting area of the LED light source is defined as S, and a total light quantity is defined as L.

Dynamic image encoding device and dynamic image decoding device

Abstract: The image encoding device of the present invention includes a direct vector determination unit 34 that excludes a direct vector derived by a direct vector calculation unit 33 from vectors targeted for averaging in the case where a unit region having, as a starting point thereof, a pixel location indicated by the direct vector includes a region outside a picture, and a motion compensation predicted image generation unit 35 that generates a motion compensation predicted image by obtaining pixel values of motion compensation predicted image for the unit region targeted for encoding, with one or more motion vectors determined by the direct vector determination unit 34.

View-dependent precomputed light transport using nonlinear Gaussian function approximations

Abstract: We propose a real-time method for rendering rigid objects with complex view-dependent effects under distant all-frequency lighting. Existing precomputed light transport approaches can render rich global illumination effects, but high-frequency view-dependent effects such as sharp highlights remain a challenge. We introduce a new representation of the light transport operator based on sums of Gaussians. The nonlinear parameters of our representation enable 1) arbitrary bandwidth because scale is encoded as a direct parameter, and 2) high-quality interpolation across view and mesh triangles because we interpolate the mean direction of the Gaussians, thereby preventing linear cross-fading artifacts. However, fitting the precomputed light transport data to this new representation requires solving a nonlinear regression problem that is more involved than traditional linear and nonlinear (truncation) approximation techniques. We present a new data fitting method based on optimization that includes energy terms aimed at enforcing artifact-free interpolation. We demonstrate that our method achieves high visual quality with a small storage cost and an efficient rendering algorithm.

Door device for elevator

Abstract: A door device for an elevator is provided with an elevator door for opening/closing a doorway through which an interior of a car communicates with a landing, a distance sensor for continuously detecting a distance from the doorway to a passenger at the landing, a processing device for obtaining a door control command corresponding to information from the distance sensor, and a door control device for controlling a movement of the elevator door based on the door control command from the processing device. Thus, the elevator door can be moved in accordance with the movement of the passenger. Accordingly, the passenger is allowed to board the car more reliably, and a running efficiency of the elevator can be enhanced.

Hybrid-excited rotating machine, and vehicle with the hybrid-excited rotating machine

Abstract: A hybrid-excited rotating machine comprising: a stator winding 12 of a multi-phase Y-connection; a plurality of rotor magnetic poles 21, 22, 23, 24, 25, 26, 27, 28 fixed on a rotor shaft 3 at a predetermined spacing in the circumferential direction and confronting the inner circumference of said stator 1 through a air gap; a plurality of permanent magnets 51, 52, 53, 54, 55, 56, 57, 58 fixed at substantially central portions of said circumferential direction of said individual rotor magnetic poles and magnetized in the radial direction of said rotor shaft; and a plurality of field windings 61, 62, 63, 64, 65, 66, 67, 68 wound individually on said rotor magnetic poles.

Performance analysis and a proposed improvement for the IEEE 802.15.4 contention access period

Abstract: IEEE 802.15.4-2003 (2003) was introduced to address the market need for connecting low-rate devices in a wireless personal area network (WPAN). A slotted CSMA/CA medium access control (MAC) protocol is defined in the standard to coordinate the channel access of a large number of wireless devices. In this paper, we propose a novel Markov chain for IEEE 802.15.4 MAC, which faithfully captures all the essential features of the protocol, and thus can provide valuable insight into the strengths and weaknesses of this multiple access scheme. The evaluation reveals that the double carrier sensing mechanism specified in 802.15.4 MAC is not an optimal design, and a slight modification in the protocol can result in further performance improvement in terms of throughput, delay and energy efficiency

Antenna/beam selection training in mimo wireless lans with different sounding frames

Abstract: A method selects antennas in a multiple-input, multiple-output (MIMO) wireless local area network (WLAN) that includes a plurality of stations, and each station includes a set of antennas. Plural consecutive packets, received at a station, include plural consecutive sounding packets. Each sounding packet corresponds to a different subset of the set of antennas, and at least one of the plural consecutive packets includes a high throughput (HT) control field including a signal to initiate antenna selection and a number N indicative of a number of sounding packets which follow the at least one packet including the HT control field and which are to be used for antenna selection. A channel matrix is estimated based on a characteristic of the channel as indicated by the received N sounding packets, and a subset of antennas is selected according to the channel matrix. Station and computer program product embodiments include similar features.

Image surveillance/retrieval system

Abstract: An object processing unit divides each image frame of received image data into block areas, extracts an object from each image frame, and extracts, as metadata, the features of this object for each block area. A real-time detection processing unit compares the metadata extracted for each block area with a received real-time detection query, and detects an object which satisfies the real-time detection query. A post-retrieval processing unit compares the metadata for each block area stored in a metadata storage unit with a received post-retrieval query, and retrieves an object which satisfies the post-retrieval query.

Polarization modulation of terahertz electromagnetic radiation by four-contact photoconductive antenna

Abstract: Generation and modulation of circularly polarized terahertz electromagnetic radiation have been demonstrated by using a four-contact photoconductive antenna and a total-reflection Si prism. The quality of the circularly polarized terahertz pulsed radiation has been evaluated by using a polarization sensitive terahertz time-domain spectroscopy system. The characteristic of the dynamic modulation between the left and right circularly polarized states of the THz radiation is also evaluated. The ellipticity of the modulated circularly polarized THz radiation without a polarizer is not as good as that of the non-modulated because of the non-uniform bias field distribution and the asymmetric pump laser intensity profile on the photoconductive gap.

Multi-band radio communication method and base station

Abstract: In a radio communication system simultaneously providing a communication service by using a plurality of discontinuous frequency bands, a multi-band radio communication method allocates a band for a mobile station requested to start communication by a base station constituting the system. For example, a particular reception unit in the base station extracts control information on the channel state of each frequency band and recognizes the reception-enabled frequency band from the extraction result. A channel control unit (9) judges whether a new traffic corresponding to the communication start request can be allocated successively in the descending order of the high frequency band.

Analysis of PD-generated SF/sub 6/ decomposition gases adsorbed on carbon nanotubes

Abstract: Chemical byproducts analysis has been recognized as a powerful diagnosis method for SF6 gas-insulated switchgear (GIS). The authors have previously demonstrated that a carbon nanotube (CNT) gas sensor could detect partial discharge (PD) generated in SF6 gas. However, PD-generated decomposition gas species, which were responsible for the CNT gas sensor response, have not been identified yet. In this paper, two kinds of experiments were conducted in order to identify the responsible decomposition gas species. At first, the decomposition gas molecules adsorbed on CNTs were analyzed by Fourier transformation infrared (FTIR) spectroscopy. FTIR absorbance was observed around 735 cm-1 after CNTs were exposed to PD generated in SF6. In the second experiment, the CNT gas sensor responses to typical SF6 decomposition products (HF and SF4) were examined. The CNT gas sensor responded to these gases in the same way as to PD generated in SF6. SF4 response was larger than HF response. Based on these results, SF 4 and SOF2 emerged as candidates for the responsible decomposition gases. Electrochemical interactions between adsorbed gas molecules and CNT were discussed based on theoretical predictions of molecular orbital calculations. The calculation results suggested that both of SOF2 and SF4 could increase the CNT gas sensor conductance

High-performance speed servo system considering Voltage saturation of a vector-controlled induction motor

Abstract: Generally, a speed servo system of a vector-controlled induction motor has limitations of motor voltage and current. When the speed servo system has a large torque reference, the output of its PI controller is often saturated. In this case, the conventional servo system stops the integral calculation of its PI controller. However, this system often has a large overshoot and/or an oscillated response caused by both a windup phenomenon and phase error on the vector control condition. This paper proposes a new speed servo system considering voltage saturation for the vector-controlled induction motor. The proposed control method compensates the phase error on vector control condition quickly, and always keeps the vector control condition. The experimental results show that the proposed system well regulates the motor speed and the secondary magnetic flux for a large torque reference without a windup phenomenon.

Refrigerating/air conditioning system having refrigerant learage detecting function, refrigerator/air conditioner and method for detecting leakage of refrigerant

Abstract: A refrigerating/air conditioning system and a method for detecting leakage of refrigerant which can detect leakage of a trace of refrigerant automatically while performing air conditioning operation regardless of environmental conditions or installation conditions. The refrigerating/air conditioning system, where a refrigeration cycle is constituted by connecting an outdoor unit having a compressor, an outdoor heat exchanger and a restrictor with one or a plurality of indoor units having an indoor heat exchanger and a restrictor through interconnection piping, is provided with a means for judging leakage of refrigerant of the refrigeration cycle based on the past data about the quantity of refrigerant of the refrigeration cycle in the past, and new data about the quantity of refrigerant after performing stop and start of the refrigeration cycle a plurality of times since a moment in time in the past.

Bandpass Directional Couplers with Electromagnetically-Coupled Resonators

Abstract: Compact 90- and 180-degree directional couplers incorporating bandpass characteristics are presented. They can integrate a bandpass filter and a power-divider/combiner in an RF transceiver, resulting in its miniaturization. The bandpass directional coupler can be represented as a coupled-resonator network, and its coupling coefficients and external-Q can be determined from a desired coupling ratio and operational bandwidth of the bandpass coupler. Measured results are also presented on a Ku-band bandpass 180-degree directional coupler with TE 01delta-mode dielectric resonators

A Unified Framework for Video Summarization, Browsing, and Retrieval

Abstract: This chapter reviews and discusses recent research progress in multimodal analysis, representation, summarization, browsing, and retrieval. It introduces the video table of contents (ToC), the highlights, and the index, and presents techniques for constructing them. It further proposes a unified framework for video summarization, browsing, and retrieval to enable a user to go back and forth between browsing and retrieval. An essential part of the unified framework is composed of the weighted links. The links can be established between index entities and scenes, groups, shots, and key frames in the ToC structure for scripted content and between index entities and finer-resolution highlights, highlight candidates, audio-visual markers, and plays/breaks. For scripted content, focus is given on the links between index entities and shots. Shots are the building blocks of the ToC. An example of going from the visual index to the highlights is shown for unscripted content. This chapter recapitulates the key components of video highlights extraction and video retrieval. Video retrieval is concerned with how to return similar video clips to a user given a video query.

How far can we go on the x64 processors

Abstract: This paper studies the state-of-the-art software optimization methodology for symmetric cryptographic primitives on the new 64-bit x64 processors, AMD Athlon64 (AMD64) and Intel Pentium 4 (EM64T). We fully utilize newly introduced 64-bit registers and instructions for extracting maximal performance of target primitives. Our program of AES with 128-bit key runs in 170 cycles/block on Athlon 64, which is, as far as we know, the fastest implementation of AES on a PC processor. Also we implemented a “bitsliced” AES and Camellia for the first time, both of which achieved very good performance. A bitslice implementation is important from the viewpoint of a countermeasure against cache timing attacks because it does not require lookup tables with a key-dependent address. We also analyze performance of SHA256/512 and Whirlpool hash functions and show that SHA512 can run faster than SHA256 on Athlon 64. This paper exhibits an undocumented fact that 64-bit right shifts and 64-bit rotations are extremely slow on Pentium 4, which often leads to serious and unavoidable performance penalties in programming encryption primitives on this processor.

Bidirectional buck boost dc-dc converter, railway coach drive control system, and railway feeder system

Abstract: According to the present invention, a bidirectional buck boost DC-DC converter can be obtained, in which power can flow bidirectionally from a primary side to a secondary side and from the secondary side to the primary side, regardless of a magnitude relation between a secondary-side voltage and a primary-side voltage in a state where different DC voltage sources are connected to the primary side and the secondary side in the DC-DC converter. A direction and a magnitude of the power can be automatically controlled to a desired value continuously on instantaneous value basis.

System Interconnection Inverter

Abstract: A system interconnection inverter includes a step-up converter and an inverter. Moreover, the system interconnection inverter includes a short-circuit current-interrupting diode with a cathode connected to an input terminal of a negative bus, a semiconductor switch connected to an anode of the short-circuit current-interrupting diode, a semiconductor switch drive circuit that drives the semiconductor switch, a semiconductor switch-off circuit that turns off the semiconductor switch drive circuit when negative power is applied such that electric current flows from a cathode toward an anode of the input terminal, and a control circuit that controls the semiconductor switch drive circuit.

Image encoding method, image decoding method, image encoding apparatus, image decoding apparatus, image encoded bitstream and recording medium

Abstract: The present invention makes it possible to include, when encoding processing is applied to three color components using a 4:0:0 format, data for one picture in one access unit and makes it possible to set the same time information or the same set encoding modes among the respective color components. In an image encoding system for applying compression processing to an input image signal including a plurality of color components, encoded data obtained by independently subjecting an input image signal of each of the color components to encoding processing and a parameter indicating which color component the encoded data corresponds to are multiplexed with a bit stream. In an image decoding system for inputting a bit stream in which an image signal including a plurality of color components is compressed to perform decoding processing, decoding processing of the encoded data of each of the color components is performed using a parameter indicating which color component the encoded data corresponds to.

Electric Power Converter

Abstract: There are provided an electric power converter in which common-mode noise is suppressed without causing enlargement of components, increase in the number of components, a cost hike, and the like The electric power converter is provided with a capacitor ( 12 ) connected with the input terminal of the inverter circuit ( 13 a ), a noise suppression means ( 10 a, 10 b ) that is provided around at least one of input-side conductors connected with the input terminals of the inverter circuit ( 13 a ) and output-side conductors connected with the output terminals of the inverter circuit ( 13 a ), an electric quantity detector ( 11, 19 a, 19 b, 19 c ) that is provided in the input-side conductors or the output-side conductors at a position opposite to the inverter circuit with respect to the noise suppression means ( 10 a, 10 b ), and a control unit ( 20 ) that controls the inverter circuit ( 13 b ), based on an electric quantity detection signal from the electric quantity detector