The search functionality is under construction.
The search functionality is under construction.

Keyword Search Result

[Keyword] LoD(19hit)

1-19hit
  • Frequency-Dependent LOD-FDTD Method in Cylindrical Coordinates

    Jun SHIBAYAMA  Tatsuyuki HARA  Masato ITO  Junji YAMAUCHI  Hisamatsu NAKANO  

     
    BRIEF PAPER

      Vol:
    E101-C No:8
      Page(s):
    637-639

    The locally one-dimensional finite-difference time-domain (FDTD) method in cylindrical coordinates is extended to a frequency-dependent version. The fundamental scheme is utilized to perform matrix-operator-free formulations in the right-hand sides. For the analysis of surface plasmon polaritons propagating along a plasmonic grating, the computation time is significantly reduced to less than 10%, compared with the explicit cylindrical FDTD method.

  • Efficient 3-D Fundamental LOD-FDTD Method Incorporated with Memristor

    Zaifeng YANG  Eng Leong TAN  

     
    BRIEF PAPER

      Vol:
    E99-C No:7
      Page(s):
    788-792

    An efficient three-dimensional (3-D) fundamental locally one-dimensional finite-difference time-domain (FLOD-FDTD) method incorporated with memristor is presented. The FLOD-FDTD method achieves higher efficiency and simplicity with matrix-operator-free right-hand sides (RHS). The updating equations of memristor-incorporated FLOD-FDTD method are derived in detail. Numerical results are provided to show the trade-off between efficiency and accuracy.

  • Fundamental LOD-BOR-FDTD Method for the Analysis of Plasmonic Devices

    Jun SHIBAYAMA  Takuto OIKAWA  Tomoyuki HIRANO  Junji YAMAUCHI  Hisamatsu NAKANO  

     
    BRIEF PAPER

      Vol:
    E97-C No:7
      Page(s):
    707-709

    The body-of-revolution finite-difference time-domain method (BOR-FDTD) based on the locally one-dimensional (LOD) scheme is extended to a frequency-dependent version for the analysis of the Drude and Drude-Lorentz models. The formulation is simplified with a fundamental scheme, in which the number of arithmetic operations is reduced by 40% in the right-hand sides of the resultant equations. Efficiency improvement of the LOD-BOR-FDTD is discussed through the analysis of a plasmonic rod waveguide and a plasmonic grating.

  • Fundamental Locally One-Dimensional Method for 3-D Thermal Simulation

    Wei CHOON TAY  Eng LEONG TAN  Ding YU HEH  

     
    PAPER

      Vol:
    E97-C No:7
      Page(s):
    636-644

    This paper presents a fundamental locally one-dimensional (FLOD) method for 3-D thermal simulation. We first propose a locally one-dimensional (LOD) method for heat transfer equation within general inhomogeneous media. The proposed LOD method is then cast into compact form and formulated into the FLOD method with operator-free right-hand-side (RHS), which leads to computationally efficient update equations. Memory storage requirements and boundary conditions for both FLOD and LOD methods are detailed and compared. Stability analysis by means of analyzing the eigenvalues of amplification matrix substantiates the stability of the FLOD method. Additionally, the potential instability of the Douglas Gunn (DG) alternating-direction-implicit (ADI) method for inhomogeneous media is demonstrated. Numerical experiments justify the gain achieved in the overall efficiency for FLOD over LOD, DG-ADI and explicit methods. Furthermore, the relative maximum error of the FLOD method illustrates good trade-off between accuracy and efficiency.

  • Predominant Melody Extraction from Polyphonic Music Signals Based on Harmonic Structure

    Jea-Yul YOON  Chai-Jong SONG  Hochong PARK  

     
    LETTER-Music Information Processing

      Vol:
    E96-D No:11
      Page(s):
    2504-2507

    A new method for predominant melody extraction from polyphonic music signals based on harmonic structure is proposed. The proposed method first extracts a set of fundamental frequency candidates by analyzing the distance between spectral peaks. Then, the predominant fundamental frequency is selected by pitch tracking according to the harmonic strength of the selected candidates. Finally, the method runs pitch smoothing on a large temporal scale for eliminating pitch doubling error, and conducts voicing frame detection. The proposed method shows the best overall performance for ADC 2004 DB in the MIREX 2011 audio melody extraction task.

  • High-Tc Superconducting Electronic Devices Based on YBCO Step-Edge Grain Boundary Junctions Open Access

    Shane T. KEENAN  Jia DU  Emma E. MITCHELL  Simon K. H. LAM  John C. MACFARLANE  Chris J. LEWIS  Keith E. LESLIE  Cathy P. FOLEY  

     
    INVITED PAPER

      Vol:
    E96-C No:3
      Page(s):
    298-306

    We outline a number of high temperature superconducting Josephson junction-based devices including superconducting quantum interference devices (SQUIDs) developed for a wide range of applications including geophysical exploration, magnetic anomaly detection, terahertz (THz) imaging and microwave communications. All these devices are based on our patented technology for fabricating YBCO step-edge junction on MgO substrates. A key feature to the successful application of devices based on this technology is good stability, long term reliability, low noise and inherent flexibility of locating junctions anywhere on a substrate.

  • Optimization of Langmuir-Blodgett Film Formation for Organic-Inorganic Layer Perovskite by Squeeze out Method

    Koichi SOUDA  Koichi SAKAGUCHI  Masanao ERA  

     
    BRIEF PAPER

      Vol:
    E96-C No:3
      Page(s):
    372-373

    In order to obtain the uniform film having well-defined lead halide-based layer perovskite structure, we proposed squeezed out method. It is found that the optimized condition with respect to docosylammonium bromide is revealed by employing hexadecylammonium bromide among tetradecylammonium bromide, hexadecylammonium bromide and octadecylammonium bromide.

  • Frequency-Dependent Formulations of a Drude-Critical Points Model for Explicit and Implicit FDTD Methods Using the Trapezoidal RC Technique

    Jun SHIBAYAMA  Keisuke WATANABE  Ryoji ANDO  Junji YAMAUCHI  Hisamatsu NAKANO  

     
    PAPER-Electromagnetic Theory

      Vol:
    E95-C No:4
      Page(s):
    725-732

    A Drude-critical points (D-CP) model for considering metal dispersion is newly incorporated into the frequency-dependent FDTD method using the simple trapezoidal recursive convolution (TRC) technique. Numerical accuracy is investigated through the analysis of pulse propagation in a metal (aluminum) cladding waveguide. The TRC technique with a single convolution integral is found to provide higher accuracy, when compared with the recursive convolution counterpart. The methodology is also extended to the unconditionally stable FDTD based on the locally one-dimensional scheme for efficient frequency-dependent calculations.

  • Organic-Inorganic Hybrid Ultra-Thin Films Applied to Glucose Biosensor

    Huihui WANG  Hitoshi OHNUKI  Hideaki ENDO  Mitsuru IZUMI  

     
    BRIEF PAPER

      Vol:
    E94-C No:12
      Page(s):
    1855-1857

    Thin film glucose biosensors were fabricated with organic/inorganic hybrid films based on glucose oxidase (GOx) and Prussian Blue nano-clusters. The biosensors composed of hybrid films were characterized by the low operating potential and the advantage to interference-free detection. In this research, we employed two kinds of thin films for GOx immobilization: Langmuir-Blodgett (LB) and self-assembled monolayer (SAM). The LB film immobilizes GOx in its inside through the electrostatic force, while the SAM immobilizes GOx with the covalent bond. The sensors with LB film produced a relatively high current signal, while the non-linear behavior and a low stability were recognized. On the other hand, the sensors with SAM presented a good linear relationship and a very stable performance.

  • Novel Humidity and Gas Detector Using Langmuir-Blodgett Cellulose-Thin-Film Coated Quartz Crystal Oscillator

    Hiroyuki KUSANO  Masahiko KITAGAWA  

     
    PAPER-Materials & Devices

      Vol:
    E91-C No:12
      Page(s):
    1876-1880

    We have developed novel humidity and gas detector system using quartz crystal oscillators (QCO) deposited with cellulose Langmuir-Blodgett (LB) films. We have realized stable humidity detection by the LB-based QCO sensor for extremely high humidity subsequent to the water dipping condition. Also, specific gaseous molecules such as alcohol could have been sensitively detected.

  • Melody Track Selection Using Discriminative Language Model

    Xiao WU  Ming LI  Hongbin SUO  Yonghong YAN  

     
    LETTER-Music Information Processing

      Vol:
    E91-D No:6
      Page(s):
    1838-1840

    In this letter we focus on the task of selecting the melody track from a polyphonic MIDI file. Based on the intuition that music and language are similar in many aspects, we solve the selection problem by introducing an n-gram language model to learn the melody co-occurrence patterns in a statistical manner and determine the melodic degree of a given MIDI track. Furthermore, we propose the idea of using background model and posterior probability criteria to make modeling more discriminative. In the evaluation, the achieved 81.6% correct rate indicates the feasibility of our approach.

  • Music Style Mining and Classification by Melody

    Man-Kwan SHAN  Fang-Fei KUO  

     
    LETTER-Speech and Hearing

      Vol:
    E86-D No:3
      Page(s):
    655-659

    Music style is one of the features that people used to classify music. Discovery of music style is helpful for the design of content-based music retrieval systems. In this paper we investigated the mining and classification of music style by melody from a collection of MIDI music. We extracted the chord from the melody and investigated the representation of extracted features and corresponding mining techniques for music classification. Experimental results show that the classification achieved 64% to 84% accuracy for two-way classification.

  • Molecular Engineering of Non-Centrosymmetric Langmuir-Blodgett Films for NLO Applications: Films with Interlocking Lego-Type Structures

    Geoffrey J. ASHWELL  Dejian ZHOU  Karl SKJONNEMAND  

     
    INVITED PAPER-Ultra Thin Film

      Vol:
    E83-C No:7
      Page(s):
    1057-1061

    The cationic dye, E-N-alkyl-4-[2-(4-alkyloxynaphthyl) ethenyl] quinolinium bromide has a wide-bodied chromophore with alkyl groups at opposite ends, i. e. CmH2m+1-D-π-A+-CnH2n+1 X-, where D and A are electron-donor and electron-acceptor groups respectively, π is a conjugated bridge and X- is the bromide counterion. It forms non-centrosymmetric Langmuir-Blodgett (LB) structures in which the packing is dependent upon the combination and compatibility of the alkyl groups. Films of two isomeric analogues where m + n = 34, have a layer thickness of 4.3 nm when the groups are significantly different (m = 12 and n = 22) which decreases to 2.5 nm when they are similar (m = 18 and n = 16). The latter adopts an interdigitating layer arrangement at both the upper and lower interfaces and it is the first example of a Lego-type structure with non-centrosymmetric alignment of the optically nonlinear chromophores. This is evidenced by the second-harmonic intensity, which increases quadratically with the number of layers, i. e. as .

  • Real-Time Spatial Data Management for Scalable Networked Augmented Virtual Spaces

    Masatoshi ARIKAWA  Shinji SHIMOJO  Akira AMANO  Kaori MAEDA  Reiji AIBARA  Kouji NISHIMURA  Kaduo HIRAKI  Kazutoshi FUJIKAWA  

     
    PAPER-Spatial and Temporal Databases

      Vol:
    E82-D No:1
      Page(s):
    99-112

    This paper proposes a new framework of managing virtual spaces based on spatial databases as an extension of VRML-based systems. The framework is suitable for treating continuous virtual spaces and for managing the quality of service (QoS) of the virtual spaces depending on user's operations and situations of computer resources. Levels of detail (LoD) of 3D objects is the most important rule for rendering scenes dynamically while managing the QoS. This paper describes a method of managing the QoS depending on the LoD in the form of spatial queries. An advantage of the framework is that spatial databases can incrementally construct virtual spaces in clients using differential descriptions based on VRML, that is, DVRML, proposed in this paper. Dynamic spatial data such as avatar's movement and real-time multimedia data such as videos should be shared by all participants in a virtual space in real time. Our framework can also handle dynamic spatial data by means of real-time updating of some spatial objects in spatial databases as well as static spatial data. We developed some experimental applications based on the framework in order to prove that it is feasible for networked virtual spaces with video components.

  • Recent Progress in Organic Film Devices for Optics and Electronics

    Keiichi KANETO  Kazuhiro KUDO  Yutaka OHMORI  Mitsuyoshi ONODA  Mitsumasa IWAMOTO  

     
    REVIEW PAPER

      Vol:
    E81-C No:7
      Page(s):
    1009-1019

    Recent technologies of organic film devices are reviewed. New technologies of fabrication and characterization of organic thin films, electro-mechanical conversion materials, and applications for electrical and optical devices are discussed. In this review paper, especially organic light emitting diodes, tunneling junctions using polyimide Langmuir-Blodgett films, tunneling spectroscopy and high-density recording, plastic actuators using conducting polymers, molecular self-assembly process for fabricating organic thin film devices are reviewed.

  • Investigation of Dynamic Orientation Process of Nematic Liquid Crystals Triggered by Conformational Change of Surface Monolayer

    Yutaka MAJIMA  Keisuke KATO  Mitsumasa IWAMOTO  Kunihiro ICHIMURA  

     
    PAPER

      Vol:
    E81-C No:7
      Page(s):
    1070-1076

    We developed a measuring system that measures both capacitance and transmittance of a liquid crystal (LC) cell simultaneously. We then studied the dynamic orientation process of nematic LC molecules between two-photochromic command surfaces. The command surfaces consist of a polymer monolayer bearing azobenzene side chains and they are deposited on glass substrate coated with indium-tin-oxide by using the Langmuir-Blodgett technique. The capacitance of LC cells increased and decreased alternately due to orientation transition in LC molecules by irradiating ultraviolet (UV) and visible light, respectively. Similarly, with the alternating irradiation of UV and visible lights, the transmittance of the LC cell changed periodically. Mean tilt angles of LC molecules under irradiation of UV and visible lights were evaluated from the results of capacitance and transmittance. It was found that the transient transmittance response was delayed to the transient capacitance under the UV irradiation. This result corresponds to that the LC molecules in homeotropic mode tend to remain the optical alignment.

  • Inelastic Electron Tunneling Spectroscopy and Optical Characterization of TMPD Adsorbed Cn TCNQ Labgmuir-Blodgett Films

    Shigekazu KUNIYOSHI  Masataka NAGAOKA  Kazuhiro KUDO  Shin-ichi TERASHITA  Yukihiro OZAKI  Keiji IRIYAMA  Kuniaki TANAKA  

     
    PAPER

      Vol:
    E77-C No:5
      Page(s):
    657-661

    To investigate the effect of alkyl chain length and adsorption time on the charge-transfer complex formation, ultraviolet-visible absorption and inelastic electron tunneling (IET) spectroscopy measurements were carried out for the tetramethylphenylenediamine (TMPD; donor molecule) adsorbed dodecyl-, pentadecyl- and octadecyl-tetracyanoquinodimethane (TCNQ) Langmuir-Blodgett (LB) films. In the optical absorption spectra, the main peak of LB films shows a red-shift depending on alkyl chain length and adsorption time. Furthermore, the dependence on alkyl chain length and adsorption time are also shown in the IET spectra. These results demonstrate that adsorption LB methods enable to control the adsorption ratio of functional molecules and the CT complex formation.

  • Control of Electronic State in Organic Semiconductor by Substituent Groups

    Kazuhiro SAITO  Hiroshi YOKOYAMA  

     
    PAPER

      Vol:
    E77-C No:5
      Page(s):
    654-656

    Control of electronic states of dye molecules (organic semiconductors) by introducing appropriate substituent groups has been examined. NH2 (electron-releasing group) and NO2 (electron-withdrawing group) were introduced in thiacarbocyanine dye to modify the electronic states of the dyes. The effect of modification was examined based on the properties of photoelectric cells made by the dye derivatives. Clear increase in photocurrent, more than ten times, was observed when modified dyes were used instead of the original dye. The result shows that the introduction of substituent groups for organic semiconductors is quite effective to control the electronic states, and the introduction can be regarded as doping in molecular level.

  • Electron Transport Mechanism through Porphyrin Polyimide Langmuir-Blodgett Films

    Mitsumasa IWAMOTO  Tohru KUBOTA  

     
    PAPER

      Vol:
    E77-C No:5
      Page(s):
    662-665

    We fabricated junctions with a porphyrin polyimide (PORPI) monolayer, and then investigated the electron transport properties of the junctions from the current-voltage (I-V) and d2V/dI2-V measurements. Polyimide LB films without porphyrin were used as tunneling barriers. One large peak was seen at a voltage around 1.9 V, due to the excitation of electron transitions in PORPI molecules, whereas a step structure was not observed in the I-V characteristic.