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Showing papers by "Panasonic published in 2013"


Journal ArticleDOI
TL;DR: In this article, a gate injection transistor (GIT) is proposed to increase the drain current with low on-state resistance by conductivity modulation, which greatly helps in increasing the efficiency of power switching systems.
Abstract: This paper reviews the recent activities for normally-off GaN-based gate injection transistors (GITs) on Si substrates and their application to inverters. Epitaxial growth of the AlGaN/GaN heterostructures with good crystallinity over 200-mm Si substrates with eliminated bowing enables low-cost fabrication of GaN devices with high breakdown voltages. A novel normally-off GaN transistor called as GIT is proposed in which hole injection from the p-type AlGaN gate increases the drain current with low on-state resistance by conductivity modulation. The low on-state resistance in GaN-based devices greatly helps to increase the efficiency of power switching systems. A GaN-based three-phase inverter successfully drives a motor with high efficiency of 99.3% at a high output power of 1500 W. The presented GaN-based devices are expected to greatly help saving energy in the future as an indispensable power switching system.

329 citations


Patent
22 Nov 2013
TL;DR: In this article, an information communication method of transmitting a signal that uses a change in luminance is provided. The method includes determining a pattern of the change in the luminance by modulating the signal to be transmitted, and transmitting the signal by a light emitter changing in the measured luminance according to the determined pattern.
Abstract: An information communication method of transmitting a signal is provided that uses a change in luminance. The method includes determining a pattern of the change in luminance by modulating the signal to be transmitted, and transmitting the signal by a light emitter changing in luminance according to the determined pattern. The pattern of the change in luminance is a pattern in which one of two different luminance values occurs in each arbitrary position in a predetermined duration. The determining a pattern of change in luminance includes dividing the predetermined duration into four duration units, so that one of two different luminance value occurs in one duration unit of the four duration units and the other luminance value of the two different luminance value occurs in three duration units of the four duration units, the three duration units are other than the one duration unit.

321 citations


Proceedings ArticleDOI
02 Dec 2013
TL;DR: The evaluation protocol of the VOT2013 challenge and the results of a comparison of 27 trackers on the benchmark dataset are presented, offering a more systematic comparison of the trackers.
Abstract: Visual tracking has attracted a significant attention in the last few decades. The recent surge in the number of publications on tracking-related problems have made it almost impossible to follow the developments in the field. One of the reasons is that there is a lack of commonly accepted annotated data-sets and standardized evaluation protocols that would allow objective comparison of different tracking methods. To address this issue, the Visual Object Tracking (VOT) workshop was organized in conjunction with ICCV2013. Researchers from academia as well as industry were invited to participate in the first VOT2013 challenge which aimed at single-object visual trackers that do not apply pre-learned models of object appearance (model-free). Presented here is the VOT2013 benchmark dataset for evaluation of single-object visual trackers as well as the results obtained by the trackers competing in the challenge. In contrast to related attempts in tracker benchmarking, the dataset is labeled per-frame by visual attributes that indicate occlusion, illumination change, motion change, size change and camera motion, offering a more systematic comparison of the trackers. Furthermore, we have designed an automated system for performing and evaluating the experiments. We present the evaluation protocol of the VOT2013 challenge and the results of a comparison of 27 trackers on the benchmark dataset. The dataset, the evaluation tools and the tracker rankings are publicly available from the challenge website (http://votchallenge.net).

239 citations


Patent
28 Feb 2013
TL;DR: In this article, a portable terminal includes a receiver, a barcode former configured to form barcodes and a display, and the display displays the formed barcode formed by the receiver.
Abstract: A portable terminal includes a receiver, a barcode former configured to form barcodes and a display. The barcode former forms a barcode from the data received by the receiver and the display displays the formed barcode.

222 citations


Journal ArticleDOI
TL;DR: This paper presents bandgap reference (BGR) and sub-BGR circuits for nanowatt LSIs, which avoid the use of resistors and contain only MOSFETs and one bipolar transistor and can operate at a sub-1-V supply.
Abstract: This paper presents bandgap reference (BGR) and sub-BGR circuits for nanowatt LSIs. The circuits consist of a nano-ampere current reference circuit, a bipolar transistor, and proportional-to-absolute-temperature (PTAT) voltage generators. The proposed circuits avoid the use of resistors and contain only MOSFETs and one bipolar transistor. Because the sub-BGR circuit divides the output voltage of the bipolar transistor without resistors, it can operate at a sub-1-V supply. The experimental results obtained in the 0.18-μm CMOS process demonstrated that the BGR circuit could generate a reference voltage of 1.09 V and the sub-BGR circuit could generate one of 0.548 V. The power dissipations of the BGR and sub-BGR circuits corresponded to 100 and 52.5 nW.

219 citations


Journal ArticleDOI
04 Sep 2013
TL;DR: The proposed techniques relax the requirement for high speed analog circuits, leading to less power consumption while minimizing the increase of hardware size.
Abstract: A 60GHz short-range wireless system offers new opportunities for achieving wireless high-definition video links and multi-Gb/s wireless data transfer. Recent works have realized a 60GHz transceiver by means of a cost-effective CMOS process [1-3], but using a 60GHz system in mobile terminals poses the difficult challenge of achieving low power consumption as well as small form factor. The publication [3] achieves a power consumption of less than 756mW, but uses a simple MAC protocol incompatible with global standards and also suffers from a limited distance of less than 4cm. This paper presents a fully integrated transceiver chipset based on WiGig/IEEE802.11ad standards targeting mobile usage. The chipset is developed for a single-carrier (SC) modulation, which is suitable for reduced power consumption as compared to using OFDM modulation. However, the SC modulation is sensitive to in-band amplitude variation, mainly made worse by the gain variation of analog circuits and multipath delay spread. In order to compensate for those gain variations, the proposed chipset employs built-in TX in-band calibration and an RX frequency domain equalizer (FDE). The proposed techniques can relax the requirement for high speed analog circuits, leading to less power consumption while minimizing the increase of hardware size.

163 citations


Patent
12 Dec 2013
TL;DR: In this paper, a nitride semiconductor device with a semiconductor multilayer body is described, where a gate electrode (109) is in Schottky contact with the third-layer gate.
Abstract: Disclosed is a nitride semiconductor device, which has a semiconductor multilayer body (103) that includes a first nitride semiconductor layer (104) and a second nitride semiconductor layer (105) which are sequentially formed on a substrate (101). On the semiconductor multilayer body (103), a p-type third nitride semiconductor layer (108) is selectively formed, and on the third nitride semiconductor layer (108), a gate electrode (109) is formed. On the both sides of the third nitride semiconductor layer (108) on the semiconductor multilayer body (103), a first ohmic electrode (106) and a second ohmic electrode (107) are formed, respectively. The first gate electrode (109) is in Schottky-contact with the third nitride semiconductor (108).

159 citations


Patent
28 Feb 2013
TL;DR: In this paper, a high-pass filter circuit (11a) receives the oscillation current (It), removes the fundamental frequency component of the sine wave having a single fundamental frequency, and extracts a highharmonic component.
Abstract: Provided are a metal detection method, a metal detection device, a metal detection method for a wireless power supply device, and a wireless power supply device which are capable of accurately detecting whether an object is a metal or a nonmetal. An oscillation circuit (10) oscillates and produces a sine wave having a single fundamental frequency, and excites a metal detection coil (Ls) by the oscillation current (It) of the sine wave. An electromagnetic wave of the sine wave having the single fundamental frequency is radiated from the metal detection coil (Ls). A high-pass filter circuit (11a) receives the oscillation current (It), removes the fundamental frequency component from the oscillation current (It), and extracts a high-harmonic component of the fundamental frequency. A comparison circuit (12) determines the presence or absence of a metal.

149 citations


Journal ArticleDOI
TL;DR: This paper presents a 60-GHz direct-conversion RF front-end and baseband transceiver including analog and digital circuitry for PHY functions, capable of more than 7-Gb/s 16QAM wireless communication for every channel of the 60- GHz standards, which can be extended up to 10 Gb/s.
Abstract: This paper presents a 60-GHz direct-conversion RF front-end and baseband transceiver including analog and digital circuitry for PHY functions. The 65-nm CMOS front-end consumes 319 and 223 mW in transmitting and receiving mode, respectively. It is capable of more than 7-Gb/s 16QAM wireless communication for every channel of the 60-GHz standards, which can be extended up to 10 Gb/s. The 40-nm CMOS baseband including analog, digital, and I/O consumes 196 and 427 mW for 16QAM in transmitting and receiving modes, respectively. In the analog baseband, a 5-b 2304-MS/s ADC consumes 12 mW, and a 6-b 3456-MS/s DAC consumes 11 mW. In the digital baseband integrating all PHY functions, a (1440, 1344) LDPC decoder consumes 74 mW with the low energy efficiency of 11.8 pJ/b. The entire system including both RF and BB using a 6-dBi antenna built in the organic package can transmit 3.1 Gb/s over 1.8 m in QPSK and 6.3 Gb/s over 0.05 m in 16QAM.

142 citations


Journal ArticleDOI
Seiji Nishiwaki1, Tatsuya Nakamura1, Masao Hiramoto1, Toshiya Fujii1, Masaaki Suzuki1 
TL;DR: In this paper, color filters that split light by employing near-field interference effects instead of absorption provide enhanced signal levels for dense, small-pixel image sensors, which can be used for image classification.
Abstract: Colour filters that split light by employing near-field interference effects instead of absorption provide enhanced signal levels for dense, small-pixel image sensors.

129 citations


Patent
24 May 2013
TL;DR: In this paper, an information communication method is proposed to set an exposure time of an image sensor to less than or equal to 1/2000 seconds, so that, in an image obtained by capturing a subject by the camera, a stripe bright line parallel to a plurality of exposure lines included in the image sensor appears according to a change in luminance of the subject.
Abstract: An information communication method includes: setting an exposure time of an image sensor to less than or equal to 1/2000 second so that, in an image obtained by capturing a subject by the image sensor, a stripe bright line parallel to a plurality of exposure lines included in the image sensor appears according to a change in luminance of the subject; obtaining the image including the stripe bright line parallel to the plurality of exposure lines by, using the set exposure time, starting exposure sequentially for the plurality of exposure lines each at a different time; and obtaining information by demodulating data according to, in a pattern of the bright line included in the obtained image, a brightness change in a direction perpendicular to the plurality of exposure lines.

Journal ArticleDOI
TL;DR: In this article, the retention model of a bipolar ReRAM considering the percolative paths in a conductive filament is proposed, and it is shown that the control of oxygen vacancy concentration in the filament is the key for ensuring data retention including tail bits.
Abstract: The retention model of a bipolar ReRAM considering the percolative paths in a conductive filament is proposed. We demonstrate, for the first time, that the control of oxygen vacancy concentration in a conductive filament is the key for ensuring data retention including tail bits. To improve the retention property under low-current operation, the size of the conductive filament must be scaled down while keeping the density of oxygen vacancy high enough. Based on this concept, we demonstrate both low-current operation and sufficient retention results exceeding 500 h at 150°C, which correspond to more than 10 years at 85°C.

Proceedings ArticleDOI
01 Dec 2013
TL;DR: The Deformable Mixture Parsing Model (DMPM) thus directly solves the problem of human parsing by searching for the best graph configuration from a pool of Parse let hypotheses without intermediate tasks.
Abstract: In this work, we address the problem of human parsing, namely partitioning the human body into semantic regions, by using the novel Parselet representation. Previous works often consider solving the problem of human pose estimation as the prerequisite of human parsing. We argue that these approaches cannot obtain optimal pixel level parsing due to the inconsistent targets between these tasks. In this paper, we propose to use Parselets as the building blocks of our parsing model. Parselets are a group of parsable segments which can generally be obtained by low-level over-segmentation algorithms and bear strong semantic meaning. We then build a Deformable Mixture Parsing Model (DMPM) for human parsing to simultaneously handle the deformation and multi-modalities of Parselets. The proposed model has two unique characteristics: (1) the possible numerous modalities of Parse let ensembles are exhibited as the ``And-Or" structure of sub-trees, (2) to further solve the practical problem of Parselet occlusion or absence, we directly model the visibility property at some leaf nodes. The DMPM thus directly solves the problem of human parsing by searching for the best graph configuration from a pool of Parse let hypotheses without intermediate tasks. Comprehensive evaluations demonstrate the encouraging performance of the proposed approach.

Patent
Taiji Sasaki1, Hiroshi Yahata1
06 Aug 2013
TL;DR: In this paper, a method for providing a video includes: (a) acquiring a first main video captured of a first capture space, and (b) generating a wide-angle video by combining the plurality of main videos acquired in step (a); (c) acquiring user preference information via a network; and (d) calculating a region to be cropped which is a region of the wideangle video and smaller than the area captured in the wide angle video.
Abstract: A method for providing a video includes: (a) acquiring a first main video captured of a first capture space, and a second main video captured of a second capture space including a space other than the first capture space; (b) generating a wide-angle video by combining the plurality of main videos acquired in step (a); (c) acquiring user preference information via a network; (d) calculating a region to be cropped which is a region of the wide-angle video and smaller than the area captured in the wide-angle video, based on the user preference information acquired in step (c); (e) cropping the wide-angle video into the cropping region; and (f) providing, to a user, a cropped video generated by cropping the wide-angle video.

Proceedings ArticleDOI
23 Jun 2013
TL;DR: A subcategory-aware object classification framework to boost category level object classification performance and build the instance affinity graph by combining both intra-class similarity and inter-class ambiguity.
Abstract: In this paper, we introduce a subcategory-aware object classification framework to boost category level object classification performance. Motivated by the observation of considerable intra-class diversities and inter-class ambiguities in many current object classification datasets, we explicitly split data into subcategories by ambiguity guided subcategory mining. We then train an individual model for each subcategory rather than attempt to represent an object category with a monolithic model. More specifically, we build the instance affinity graph by combining both intra-class similarity and inter-class ambiguity. Visual subcategories, which correspond to the dense sub graphs, are detected by the graph shift algorithm and seamlessly integrated into the state-of-the-art detection assisted classification framework. Finally the responses from subcategory models are aggregated by subcategory-aware kernel regression. The extensive experiments over the PASCAL VOC 2007 and PASCAL VOC 2010 databases show the state-of-the-art performance from our framework.

Journal ArticleDOI
TL;DR: In this paper, the authors investigated the electrochemical behavior of nonstoichiometric silicon suboxides (SiO x, for x = 0.17 − 1.34) as the anode material for lithium rechargeable batteries.

Journal ArticleDOI
TL;DR: The binding mechanism of ThT with several variants of the human telomeric sequence in the presence of monovalent cations is investigated and results are crucial for the sensible design and interpretation of G-quadruplex detection assays using fluorescent ligands in general and ThT in particular.
Abstract: Thioflavin T (ThT), a typical probe for protein fibrils, also binds human telomeric G-quadruplexes with a fluorescent light-up signal change and high specificity against DNA duplexes. Cell penetration and low cytotoxicity of fibril probes having been widely established, modifying ThT and other fibril probes is an attractive means of generating new G-quadruplex ligands. Thus, elucidating the binding mechanism is important for the design of new drugs and fluorescent probes based on ThT. Here, we investigated the binding mechanism of ThT with several variants of the human telomeric sequence in the presence of monovalent cations. Fluorescence titrations and electrospray ionization mass spectrometry (ESI-MS) analyses demonstrated that each G-quadruplex unit cooperatively binds to several ThT molecules. ThT brightly fluoresces when a single ligand is bound to the G-quadruplex and is quenched as ligand binding stoichiometry increases. Both the light-up signal and the dissociation constants are exquisitely sensitive to the base sequence and to the G-quadruplex structure. These results are crucial for the sensible design and interpretation of G-quadruplex detection assays using fluorescent ligands in general, and ThT in particular.

Patent
06 Feb 2013
TL;DR: In this article, the authors propose methods for improving a scheduling request transmission between a UE and a base station by implementing a threshold that the data in the transmission buffer has to reach, before a transmission of the scheduling request is triggered.
Abstract: The invention relates to methods for improving a scheduling request transmission between a UE and a base station. The transmission of the scheduling request is postponed, by implementing a threshold that the data in the transmission buffer has to reach, before a transmission of the scheduling request is triggered. In one variant, the data in the transmission buffer needs to reach a specific amount, to trigger a scheduling request. The invention refers to further improvements: the PDDCH monitoring time window is delayed after sending a scheduling request; the dedicated scheduling request resources of the PUCCH are prioritized differently such that low-priority scheduling requests are transmitted less often.

Journal ArticleDOI
TL;DR: When sprouts were irradiated with UV-B light at wavelengths of 260-300 nm, yellowing or withering occurred within 24h of irradiation, indicating that wavelengths in this range are detrimental to the growth of buckwheat sprouts.

Patent
Kazufumi Nagazoe1
31 Jul 2013
TL;DR: In this paper, a lighting control system includes lighting fixture having identification information, controller for setting lighting condition for dimming level and color temperature of illumination light of lighting fixture, and dimmer for outputting dimming signal to lighting fixture.
Abstract: Lighting control system includes lighting fixture having identification information, controller for setting lighting condition for dimming level and color temperature of illumination light of lighting fixture, and dimmer for outputting dimming signal to lighting fixture. Lighting fixture includes dimmer for modulating illumination light to superpose thereon information signal containing identification information and lighting information of lighting fixture. Controller includes wireless communication unit for outputting control signal to dimmer, display unit with touch panel, for displaying image of lighting fixture, and visible light receiver for reading identification information and lighting information from information signal superposed on illumination light. Display unit is configured to associate identification information read through visible light receiver with image of lighting fixture to display image so as to reflect lighting information.

Patent
04 Mar 2013
TL;DR: In this article, a moving picture coding method for CBF signals is described, where the first processing unit is transformed into a frequency domain coefficient and quantized in the second processing unit.
Abstract: A moving picture coding method includes (i) transforming, for each of one or more second processing units included in the first processing unit, a moving picture signal in a spatial domain into a frequency domain coefficient and quantizing the frequency domain coefficient, and (ii) performing arithmetic coding on a luminance CBF flag indicating whether or not a quantized coefficient is included in the second processing unit in which transform and quantization are performed, wherein, in the arithmetic coding, a probability table for use in arithmetic coding is determined according to whether or not the size of the first processing unit is identical to the size of the second processing unit and whether or not the second processing unit has a predetermined maximum size.

Patent
14 Feb 2013
TL;DR: In this paper, the authors proposed a dynamic bundling of transmission time intervals in a multicarrier communication system, in which the transmission and reception is performed on a transmission time interval basis.
Abstract: The present invention relates to transmitting and receiving data in a multicarrier communication system in which the transmission and reception is performed on a transmission time interval basis. In particular, dynamic bundling of transmission time intervals is dynamically configurable for each scheduling assignment. The dynamic bundling may be applied in uplink and/or in downlink transmission between a terminal and a network node.

Patent
11 Jan 2013
TL;DR: In this article, a reception processing unit (203) receives a reference signal transmitted from a specific transmission point and control information, and receives a signal received from a transmission point other than the specific transmitter, this signal being received in resources comprising, from among a reference-signal resource group, a resource of a first number specified from the control information.
Abstract: Provided is a terminal that can accurately measure channel information between the terminal and each TP subjected to CoMP control. In this terminal, a reception processing unit (203) receives a reference signal transmitted from a specific transmission point and control information, and receives a signal transmitted from a transmission point other than the specific transmission point, this signal being received in resources comprising, from among a reference-signal resource group, a resource of a first number specified from the control information, and a resource of a second number separated from the first number by a predetermined number. A CSI generation unit (206) uses the reference signal and a signal received by an interference measurement resource to generate channel information. A transmission signal-forming unit (208) transmits the generated channel information.

Patent
Mihail Petrov1
16 Jan 2013
TL;DR: In this paper, a transmission method that converts an encoded block of data into first complex symbols each including a real component and an imaginary component, one or which is designated as a first component and the other as a second component, is presented.
Abstract: Provided is a transmission method that converts an encoded block of data into first complex symbols each including a real component and an imaginary component, one or which is designated as a first component and the other as a second component; writes the first components and the second components of the first complex symbols respectively column by column into a first interleaver matrix and a second interleaver matrix having N R rows; applies a cyclic shift to each column of the second interleaver matrix in accordance with a predetermined shift pattern; and reads the first components from the first interleaver matrix and the second components from the cyclically shifted second interleaver matrix row by row. N R is a multiple of N RF greater than N RF (N RF being an integer greater than one), and the shift pattern for the cyclic shift includes only integers that are not a multiple of N RF .

Proceedings ArticleDOI
28 Mar 2013
TL;DR: A SAR ADC with 71dB SNDR that runs at 50MS/s and consumes 4.2mW is described, which uses 3 SNDR-enhancement techniques that utilize noise and that have good compatibility to low-voltage fine digital processes.
Abstract: SAR-ADC power efficiency has improved due to its digitally oriented nature that utilizes the high switching speed of nanometer CMOS processes. In recent reports, time-interleaving techniques and multi-bit-per-cycle conversion have boosted speed to the GHz sampling range at low power consumption. However, to achieve SNR of >70dB at moderate sampling speed, SARs still need a lot of power, namely tens of mW [1-2]. In [1], a very high SNR of 90dB is achieved by a stage to amplify residue charge, which is one of the reasons for the 105mW power consumption at 12.5MS/s. In [2], 8× oversampling and a static current pre-amplifier for the comparator improve SNR to 88dB, but the ADC still consumes 66mW. In [3], digital calibration achieves an SNDR of 71dB at 3mW, but double conversion limits the sampling speed to 22.5MS/s.This paper describes a SAR ADC with 71dB SNDR that runs at 50MS/s and consumes 4.2mW. The ADC uses 3 SNDR-enhancement techniques that utilize noise and that have good compatibility to low-voltage fine digital processes.

Proceedings ArticleDOI
28 Mar 2013
TL;DR: The link budget of multi-Gb/s wireless communication systems around 60GHz improves by beamforming, and the sliding-IF architecture of [3] uses RF phase shifting, which deteriorates noise performance.
Abstract: The link budget of multi-Gb/s wireless communication systems around 60GHz improves by beamforming. CMOS realizations for this type of communication are mostly limited to either one-antenna systems [1], or beamforming ICs that do not implement all radio functions [2]. The sliding-IF architecture of [3] uses RF phase shifting, which deteriorates noise performance.

Patent
15 Nov 2013
TL;DR: In this article, an electronic component mounting system is proposed to correct a variation of the height position of an individual substrate and to prevent a mounting failure due to positional error in the height direction of the substrate.
Abstract: To provide an electronic component mounting system and an electronic component mounting method which can prevent a mounting failure due to positional error in a height direction of a substrate and ensure mounting quality. The electronic component mounting system includes a plurality of electronic component mounting devices connected to one another and mounts an electronic component on a substrate to manufacture a mounting substrate. A print test device for testing the substrate after solder printing measures a height position of a height measurement point set on the upper surface of the substrate 4 by a height measuring machine 22 and outputs a measurement result as substrate height data. In a component placing step using an electronic component placing device, a control parameter for controlling a component placing operation of the placing head 32 is updated. Accordingly, it is possible to correct a variation of the height position of an individual substrate and to prevent a mounting failure due to positional error in the height direction of the substrate.

Journal ArticleDOI
TL;DR: In this paper, a bacterial detection technique and device that utilizes advantages of both positive and negative dielectrophoresis (DEP) has been proposed and demonstrated, which has two microelectrodes, which serve as a bacteria concentrator using negative DEP (n-DEP) and a bacteria detector using positive DEP(p-DEP), respectively.
Abstract: In this study, a bacterial detection technique and device that utilizes advantages of both positive and negative dielectrophoresis (DEP) has been proposed and demonstrated. The device has two microelectrodes, which serve as a bacteria concentrator using negative DEP (n-DEP) and as a bacteria detector using positive DEP (p-DEP), respectively. Bacteria flowing into the device are repelled under action of n-DEP force exerted by the first microelectrode, and are pushed toward the second microelectrode situated at the downstream. Then concentrated bacteria are finally captured by p-DEP on the second microelectrode and detected by dielectrophoretic impedance measurement (DEPIM) method. The numerical simulations and experiments proved that n-DEP concentrator could make DEPIM sensitivity two times higher than that without n-DEP as a result of increased number of bacteria trapped on the p-DEP microelectrode.

Patent
Tomohiro Koganei1
26 Sep 2013
TL;DR: A speech recognition apparatus includes a speech acquisition unit which acquires speech uttered by a user, a recognition result acquisition unit that acquires a result of recognition performed on the acquired speech, an extraction unit which, when the recognition result includes a keyword and a selection command that is used for selecting one of selectable information items, extracts a selection candidate that includes the keyword, and a display control unit which changes a display manner of the display information according to the second selection mode switched from the first selection mode.
Abstract: A speech recognition apparatus includes: a speech acquisition unit which acquires speech uttered by a user; a recognition result acquisition unit which acquires a result of recognition performed on the acquired speech; an extraction unit which, when the recognition result includes a keyword and a selection command that is used for selecting one of selectable information items, extracts a selection candidate that includes the keyword; a selection mode switching unit which, when more than one selection candidate is extracted, switches a selection mode from a first selection mode that allows selection among the selectable information items to a second selection that allows selection among the selection candidates; a display control unit which changes a display manner of the display information, according to the second selection mode switched from the first selection mode; and a selection unit which selects one of the selection candidates, according to an entry from the user.

Journal ArticleDOI
TL;DR: Two types of mental fatigue may produce different alterations of the spontaneous oscillatory MEG activities and these findings would provide new perspectives on the neural mechanisms underlying mental fatigue.
Abstract: Fatigue has a multi-factorial nature. We examined the effects of two types of mental fatigue on spontaneous oscillatory brain activity using magnetoencephalography (MEG). Participants were randomly assigned to two groups in a single-blinded, crossover fashion to perform two types of mental fatigue-inducing experiments. Each experiment consisted of a 30-min fatigue-inducing 0- or 2-back test session and two evaluation sessions performed just before and after the fatigue-inducing mental task session. After the 0-back test, decreased alpha power was indicated in the right angular gyrus and increased levels in the left middle and superior temporal gyrus, left postcentral gyrus, right superior frontal gyrus, left inferior frontal gyrus, and right medial frontal gyrus. After the 2-back test, decreased alpha power was indicated in the right middle and superior frontal gyrus and increased levels in the left inferior parietal and superior parietal lobules, right parahippocampal gyrus, right uncus, left postcentral gyrus, left middle frontal gyrus, and right inferior frontal gyrus. For beta power, increased power following the 0-back test was indicated in the left middle temporal gyrus, left superior frontal gyrus, left cingulate gyrus, and left precentral gyrus. After the 2-back test, decreased power was suggested in the left superior frontal gyrus and increased levels in the left middle temporal gyrus and left inferior parietal lobule. Some of these brain regions might be associated with task performance during the fatigue-inducing trials. Two types of mental fatigue may produce different alterations of the spontaneous oscillatory MEG activities. Our findings would provide new perspectives on the neural mechanisms underlying mental fatigue.