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4861-4880hit(21534hit)

  • Enhanced Photocurrent Generation at a Spiro-OMeTAD/AuNPs-TiO2 Interface with Grating-coupled Surface Plasmon Excitation

    Hathaithip NINSONTI  Kazuma HARA  Supeera NOOTCHANAT  Weerasak CHOMKITICHAI  Akira BABA  Sukon PHANICHPHANT  Kazunari SHINBO  Keizo KATO  Futao KANEKO  

     
    PAPER

      Vol:
    E98-C No:2
      Page(s):
    104-109

    The fabrication of a grating structure formed by a solid-state electrolyte layer on a dye-TiO$_{2}$ film by the nanoimprinting technique using a polydimethylsiloxane (PDMS) stamp and its application in photoelectric conversion devices are described. The PDMS grating pattern is imprinted from blu-ray disc recordable. A silver electrode was deposited on the patterned solid-state electrolyte layers. Surface plasmon resonance (SPR) excitation was observed in the fabricated solar cells by irradiation with white light. The photoelectric conversion properties were measured to study the effect of the two types of SPR excitations, i.e., the propagating surface plasmon on the Ag grating surface and the localized surface plasmon from the Au nanoparticles on TiO$_{2}$.

  • Improved Iterative Receiver for Co-channel Interference Suppression in MIMO-OFDM Systems

    Zhiting YAN  Guanghui HE  Weifeng HE  Zhigang MAO  

     
    LETTER-Communication Theory and Signals

      Vol:
    E98-A No:2
      Page(s):
    776-782

    Co-channel interference (CCI) is becoming a challenging factor that causes performance degradation in modern communication systems. The receiver equipped with multiple antennas can suppress such interference by exploiting spatial correlation. However, it is difficult to estimate the spatial covariance matrix (SCM) of CCI accurately with limited number of known symbols. To address this problem, this paper first proposes an improved SCM estimation method by shrinking the variance of eigenvalues. In addition, based on breadth-first tree search schemes and improved channel updating, a low complexity iterative detector is presented with channel preprocessing, which not only considers the existence of CCI but also reduces the computational complexity in terms of visited nodes in a search tree. Furthermore, by scaling the extrinsic soft information which is fed back to the input of detector, the detection performance loss due to max-log approximation is compensated. Simulation results show that the proposed iterative receiver provides improved signal to interference ratio (SIR) gain with low complexity, which demonstrate the proposed scheme is attractive in practical implementation.

  • The Implementation of Texture-Based Video Up-Scaling on Coarse-Grained Reconfigurable Architecture

    Rui SHI  Shouyi YIN  Leibo LIU  Qiongbing LIU  Shuang LIANG  Shaojun WEI  

     
    PAPER-Application

      Pubricized:
    2014/11/19
      Vol:
    E98-D No:2
      Page(s):
    276-287

    Video Up-scaling is a hotspot in TV display area; as an important brunch of Video Up-scaling, Texture-Based Video Up-scaling (TBVU) method shows great potential of hardware implementation. Coarse-grained Reconfigurable Architecture (CGRA) is a very promising processor; it is a parallel computing platform which provides high performance of hardware, high flexibility of software, and dynamical reconfiguration ability. In this paper we propose an implementation of TBVU on CGRA. We fully exploit the characters of TBVU and utilize several techniques to reduce memory I/O operation and total execution time. Experimental results show that our work can greatly reduce the I/O operation and the execution time compared with the non-optimized ones. We also compare our work with other platforms and find great advantage in execution time and resource utilization rate.

  • A Multidimensional Configurable Processor Array — Vocalise

    Jiang LI  Yusuke ATSUMARI  Hiromasa KUBO  Yuichi OGISHIMA  Satoru YOKOTA  Hakaru TAMUKOH  Masatoshi SEKINE  

     
    PAPER-Computer System

      Pubricized:
    2014/10/27
      Vol:
    E98-D No:2
      Page(s):
    313-324

    A processing system with multiple field programmable gate array (FPGA) cards is described. Each FPGA card can interconnect using six I/O (up, down, left, right, front, and back) terminals. The communication network among FPGAs is scalable according to user design. When the system operates multi-dimensional applications, transmission efficiency among FPGA improved through user-adjusted dimensionality and network topologies for different applications. We provide a fast and flexible circuit configuration method for FPGAs of a multi-dimensional FPGA array. To demonstrate the effectiveness of the proposed method, we assess performance and power consumption of a circuit that calculated 3D Poisson equations using the finite difference method.

  • A Wide Bandwidth Analog Baseband Circuit for 60-GHz Proximity Wireless Communication Receiver in 65-nm CMOS

    Masanori FURUTA  Hidenori OKUNI  Masahiro HOSOYA  Akihide SAI  Junya MATSUNO  Shigehito SAIGUSA  Tetsuro ITAKURA  

     
    PAPER

      Vol:
    E98-A No:2
      Page(s):
    492-499

    This paper presents an analog front-end circuit for a 60-GHz proximity wireless communication receiver. The feature of the proposed analog front-end circuit is a bandwidth more than 1-GHz wide. To expand the bandwidth of a low-pass filter and a voltage gain amplifier, a technique to reduce the parasitic capacitance of a transconductance amplifier is proposed. Since the bandwidth is also limited by on-resistance of the ADC sampling switch, a switch separation technique for reduction of the on-resistance is also proposed. In a high-speed ADC, the SNDR is limited by the sampling jitter. The developed high resolution VCO auto tuning effectively reduces the jitter of PLL. The prototype is fabricated in 65nm CMOS. The analog front-end circuit achieves over 1-GHz bandwidth and 27.2-dB SNDR with 224mW Power consumption.

  • Infrared Target Tracking Using Naïve-Bayes-Nearest-Neighbor

    Shujuan GAO  Insuk KIM  Seong Tae JHANG  

     
    LETTER-Image Recognition, Computer Vision

      Pubricized:
    2014/11/18
      Vol:
    E98-D No:2
      Page(s):
    471-474

    Robust yet efficient techniques for detecting and tracking targets in infrared (IR) images are a significant component of automatic target recognition (ATR) systems. In our previous works, we have proposed infrared target detection and tracking systems based on sparse representation method. The proposed infrared target detection and tracking algorithms are based on sparse representation and Bayesian probabilistic techniques, respectively. In this paper, we adopt Naïve Bayes Nearest Neighbor (NBNN) that is an extremely simple, efficient algorithm that requires no training phase. State-of-the-art image classification techniques need a comprehensive learning and training step (e.g., using Boosting, SVM, etc.) In contrast, non-parametric Nearest Neighbor based image classifiers need no training time and they also have other more advantageous properties. Results of tracking in infrared sequences demonstrated that our algorithm is robust to illumination changes, and the tracking algorithm is found to be suitable for real-time tracking of a moving target in infrared sequences and its performance was quite good.

  • Iterative Channel Estimation and Decoding via Spatial Coupling

    Shuhei HORIO  Keigo TAKEUCHI  Tsutomu KAWABATA  

     
    PAPER

      Vol:
    E98-A No:2
      Page(s):
    549-557

    For low-density parity-check codes, spatial coupling was proved to boost the performance of iterative decoding up to the optimal performance. As an application of spatial coupling, in this paper, bit-interleaved coded modulation (BICM) with spatially coupled (SC) interleaving — called SC-BICM — is considered to improve the performance of iterative channel estimation and decoding for block-fading channels. In the iterative receiver, feedback from the soft-in soft-out decoder is utilized to refine the initial channel estimates in linear minimum mean-squared error (LMMSE) channel estimation. Density evolution in the infinite-code-length limit implies that the SC-BICM allows the receiver to attain accurate channel estimates even when the pilot overhead for training is negligibly small. Furthermore, numerical simulations show that the SC-BICM can provide a steeper reduction in bit error rate than conventional BICM, as well as a significant improvement in the so-called waterfall performance for high rate systems.

  • Efficient Cloth Pattern Recognition Using Random Ferns

    Inseong HWANG  Seungwoo JEON  Beobkeun CHO  Yoonsik CHOE  

     
    LETTER-Image Recognition, Computer Vision

      Pubricized:
    2014/10/31
      Vol:
    E98-D No:2
      Page(s):
    475-478

    This paper proposes a novel image classification scheme for cloth pattern recognition. The rotation and scale invariant delta-HOG (DHOG)-based descriptor and the entire recognition process using random ferns with this descriptor are proposed independent from pose and scale changes. These methods consider maximun orientation and various radii of a circular patch window for fast and efficient classification even when cloth patches are rotated and the scale is changed. It exhibits good performance in cloth pattern recognition experiments. It found a greater number of similar cloth patches than dense-SIFT in 20 tests out of a total of 36 query tests. In addition, the proposed method is much faster than dense-SIFT in both training and testing; its time consumption is decreased by 57.7% in training and 41.4% in testing. The proposed method, therefore, is expected to contribute to real-time cloth searching service applications that update vast numbers of cloth images posted on the Internet.

  • Cuckoo Search Algorithm for Job Scheduling in Cloud Systems

    Supacheep AMTADE  Toshiyuki MIYAMOTO  

     
    LETTER

      Vol:
    E98-A No:2
      Page(s):
    645-649

    A cloud system is defined as a large scale computer system that contains running high performance computers and responds to a large number of incoming tasks over the Internet. In this paper, we consider the problem to schedule computational jobs efficiently regarding system resource constraint and introduce a cuckoo search (CS) algorithm. Experimental results show that CS outperforms the genetic algorithm in terms of fitness value.

  • Sum Rate Analysis of MU-MISO Systems with ZF Beamforming over Composite Fading Channels

    Ou ZHAO  Hidekazu MURATA  

     
    PAPER

      Vol:
    E98-A No:2
      Page(s):
    558-568

    The performance of multiuser multiple-input single-output (MU-MISO) systems is not only affected by small-scale multipath fading but also by large-scale fading (i.e., shadowing) and path loss. In this paper, we concentrate on the sum rate distribution of MU-MISO systems employing linear zero-forcing beamforming, accounting for both multipath fading and shadowing effects, as well as spatial correlation at the transmit and receiver sides. In particular, we consider the classical spatially correlated lognormal model and propose closed-form bounds on the distribution of the achievable sum rates in MU-MISO systems. With the help of these bounds, we derive a relationship between the interuser distance and sum rate corresponding to 10% of the cumulative distribution function under different environmental conditions. A practical conclusion from our results based on the considered system is that the effect of spatially correlated shadowing can be considered to be independent when the interuser distance is approximately five times the shadowing correlation distance. Furthermore, a detailed analysis of the effects of composite channel attenuation consisting of multipath fading and shadowing is also provided.

  • Diagnosis of Stochastic Discrete Event Systems Based on N-gram Models

    Miwa YOSHIMOTO  Koichi KOBAYASHI  Kunihiko HIRAISHI  

     
    PAPER

      Vol:
    E98-A No:2
      Page(s):
    618-625

    In this paper, we present a new method for diagnosis of stochastic discrete event system. The method is based on anomaly detection for sequences. We call the method sequence profiling (SP). SP does not require any system models and any system-specific knowledge. The only information necessary for SP is event logs from the target system. Using event logs from the system in the normal situation, N-gram models are learned, where the N-gram model is used as approximation of the system behavior. Based on the N-gram model, the diagnoser estimates what kind of faults has occurred in the system, or may conclude that no faults occurs. Effectiveness of the proposed method is demonstrated by application to diagnosis of a multi-processor system.

  • Transient Response Improvement of DC-DC Buck Converter by a Slope Adjustable Triangular Wave Generator

    Shu WU  Yasunori KOBORI  Nobukazu TSUKIJI  Haruo KOBAYASHI  

     
    PAPER-Energy in Electronics Communications

      Vol:
    E98-B No:2
      Page(s):
    288-295

    This paper describes a simple-yet-effective control method for a DC-DC buck converter with voltage mode control (VMC), with a triangular wave generator (TWG) which regulates the slope of triangular wave based on the input and output voltages of the converter. Using the proposed TWG, both the load and line transient responses are improved. Since the TWG provides a line feed-forward control for the line transient response, it increases the open-loop bandwidth, and then better dynamic performance is obtained. Additional required circuit components are only a voltage controlled linear resistor (VCR) and a voltage controlled current source (VCCS). Compared with the conventional voltage control, the proposed method significantly improves the line and load transient responses. Furthermore this triangular wave slope regulation scheme is simple compared to digital feed-forward control scheme that requires non-linear calculation. Simulation results shows the effectiveness of the proposed method.

  • Realization of Autonomous Clock Synchronization for Power Packet Dispatching

    Yanzi ZHOU  Ryo TAKAHASHI  Takashi HIKIHARA  

     
    LETTER-Systems and Control

      Vol:
    E98-A No:2
      Page(s):
    749-753

    In this letter, we establish a model of a digital clock synchronization method for power packet dispatching. The first-order control is carried out to a specified model to achieve the clock synchronization. From the experimental results, it is confirmed that power packets were recognized under autonomous synchronization.

  • Towards Interactive Object-Oriented Programming

    Keehang KWON  Kyunghwan PARK  Mi-Young PARK  

     
    LETTER-Software System

      Vol:
    E98-D No:2
      Page(s):
    437-438

    To represent interactive objects, we propose a choice-disjunctive declaration statement of the form $S add R$ where S, R are the (procedure or field) declaration statements within a class. This statement has the following semantics: request the user to choose one between S and R when an object of this class is created. This statement is useful for representing interactive objects that require interaction with the user.

  • Fast CU Splitting in HEVC Intra Coding for Screen Content Coding

    Mengmeng ZHANG  Yang ZHANG  Huihui BAI  

     
    LETTER-Image Processing and Video Processing

      Vol:
    E98-D No:2
      Page(s):
    467-470

    The high efficiency video coding (HEVC) standard has significantly improved compression performance for many applications, including remote desktop and desktop sharing. Screen content video coding is widely used in applications with a high demand for real-time performance. HEVC usually introduces great computational complexity, which makes fast algorithms necessary to offset the limited computing power of HEVC encoders. In this study, a statistical analysis of several screen content sequences is first performed to better account for the completely different statistics of natural images and videos. Second, a fast coding unit (CU) splitting method is proposed, which aims to reduce HEVC intra coding computational complexity, especially in screen content coding. In the proposed scheme, CU size decision is made by checking the smoothness of the luminance values in every coding tree unit. Experiments demonstrate that in HEVC range extension standard, the proposed scheme can save an average of 29% computational complexity with 0.9% Bjøntegaard Delta rate (BD-rate) increase compared with HM13.0+RExt6.0 anchor for screen content sequences. For default HEVC, the proposed scheme can reduce encoding time by an average of 38% with negligible loss of coding efficiency.

  • Performance of Non-orthogonal Multiple Access with SIC in Cellular Downlink Using Proportional Fair-Based Resource Allocation

    Nagisa OTAO  Yoshihisa KISHIYAMA  Kenichi HIGUCHI  

     
    PAPER-Wireless Communication Technologies

      Vol:
    E98-B No:2
      Page(s):
    344-351

    This paper investigates the system-level throughput of non-orthogonal multiple access (NOMA) with a successive interference canceller (SIC) in the cellular downlink assuming proportional fair (PF)-based radio resource (bandwidth and transmission power) allocation. The purpose of this study is to examine the possibility of applying NOMA with a SIC to the systems beyond the 4G cellular system. Both the mean and cell-edge user throughput are important in a real system. PF-based scheduling is known to achieve a good tradeoff between them by maximizing the product of the user throughput among users within a cell. In NOMA with a SIC, the scheduler allocates the same frequency to multiple users simultaneously, which necessitates multiuser scheduling. To achieve a better tradeoff between the mean and cell-edge user throughput, we propose and compare three power allocation strategies among users, which are jointly implemented with multiuser scheduling. Extensive simulation results show that NOMA with a SIC with a moderate number of non-orthogonally multiplexed users significantly enhances the system-level throughput performance compared to orthogonal multiple access (OMA), which is widely used in 3.9 and 4G mobile communication systems.

  • Action Recognition Using Weighted Locality-Constrained Linear Coding

    Jiangfeng YANG  Zheng MA  

     
    LETTER-Image Processing and Video Processing

      Pubricized:
    2014/10/31
      Vol:
    E98-D No:2
      Page(s):
    462-466

    Recently, locality-constrained linear coding (LLC) as a coding strategy has attracted much attention, due to its better reconstruction than sparse coding and vector quantization. However, LLC ignores the weight information of codewords during the coding stage, and assumes that every selected base has same credibility, even if their weights are different. To further improve the discriminative power of LLC code, we propose a weighted LLC algorithm that considers the codeword weight information. Experiments on the KTH and UCF datasets show that the recognition system based on WLLC achieves better performance than that based on the classical LLC and VQ, and outperforms the recent classical systems.

  • Computational Complexity of Generalized Forty Thieves

    Chuzo IWAMOTO  Yuta MATSUI  

     
    LETTER-Fundamentals of Information Systems

      Pubricized:
    2014/11/11
      Vol:
    E98-D No:2
      Page(s):
    429-432

    Forty Thieves is a solitaire game with two 52-card decks. The object is to move all cards from ten tableau piles of four cards to eight foundations. Each foundation is built up by suit from ace to king of the same suit, and each tableau pile is built down by suit. You may move the top card from any tableau pile to a tableau or foundation pile, and from the stock to a foundation pile. We prove that the generalized version of Forty Thieves is NP-complete.

  • Reproduction of Four-Leg Animal Gaits Using a Coupled System of Simple Hardware CPG Models

    Hayate KOJIMA  Yoshinobu MAEDA  Taishin NOMURA  

     
    LETTER

      Vol:
    E98-A No:2
      Page(s):
    508-509

    We proposed a hard-wired CPG hardware network to reproduce the gaits of four-legged animals. It should reproduce walking and bounding, and they should be switchable with each other by changing the value of only one voltage.

  • A Novel Discovery Channel Scheduling for Inter-Cell Device-to-Device Discovery in 3GPP LTE Asynchronous Network

    Kyunghoon LEE  Wonjun HWANG  Hyung-Jin CHOI  

     
    PAPER-Terrestrial Wireless Communication/Broadcasting Technologies

      Vol:
    E98-B No:2
      Page(s):
    370-378

    In recent 3GPP (3rd Generation Partnership Project) standardization meetings, D2D (Device-to-Device) discovery has been a major issue to support commercial/social services and public safety in disaster environment, and TDM (Time Division Multiplexing) based discovery channel structure is mainly considered to prevent mutual interference between D2D and cellular traffic. In this structure, D2D discovery among the same cell UEs (User Equipment) has no problem because they have the same timing source. However, LTE (Long Term Evolution) assumes an asynchronous network where two adjacent eNBs (evolved Node B) have a symbol-level timing offset. For that reason, asynchronous interference among discovery signals can appear in inter-cell D2D discovery. Therefore, channel re-use scheduling was studied previously in which neighboring cells do not use the same portion of the extended discovery channel and other non-neighboring cells re-use it. However, it still shows interference problems in small cell networks which cause substantial cellular traffic loss. Therefore, in this paper, we propose a novel discovery channel scheduling in which eNBs time-align their discovery channels from each other by sample-level. In the proposed scheme, serving eNB requests cell edge UEs to estimate NTD (Network Time Difference) between serving eNB and neighboring eNB. Then, considering multiple NTDs, eNB adjusts the sample position of its discovery channel based on a novel decision rule. We verify that the proposed scheme can match the discovery performance of a synchronous network with less cellular uplink loss.

4861-4880hit(21534hit)