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[Keyword] ATI(18690hit)

5701-5720hit(18690hit)

  • Enhanced Photocurrent Properties of Dye/Au-Loaded TiO2 Films by Grating-Coupled Surface Plasmon Excitation

    Hathaithip NINSONTI  Weerasak CHOMKITICHAI  Akira BABA  Wiyong KANGWANSUPAMONKON  Sukon PHANICHPHANT  Kazunari SHINBO  Keizo KATO  Futao KANEKO  

     
    BRIEF PAPER

      Vol:
    E96-C No:3
      Page(s):
    385-388

    We report enhanced photocurrent properties of dye/Au-loaded titanium dioxide (TiO2) films on Au gratings. Au-loaded TiO2 nanopowders were first synthesized by a modified sol-gel method and then prepared by the impregnation method. We also fabricated dye-sensitized solar cells, which were composed of Au grating/Au-TiO2/TMPyP-SCC LbL (20 bilayers)/electrolyte/ITO substrates. Short-circuit photo-current measurements showed that Au-loaded TiO2 with grating-coupled surface plasmon excitation can enhance the short-circuit photocurrentof the fabricated cells.

  • Clinical Application of Neuromagnetic Recordings: From Functional Imaging to Neural Decoding Open Access

    Masayuki HIRATA  Toshiki YOSHIMINE  

     
    INVITED PAPER

      Vol:
    E96-C No:3
      Page(s):
    313-319

    Magnetoencephalography (MEG) measures very weak neuromagnetic signals using SQUID sensors. Standard MEG analyses include averaged waveforms, isofield maps and equivalent current dipoles. Beamforming MEG analyses provide us with frequency-dependent spatiotemporal information about the cerebral oscillatory changes related to not only somatosensory processing but also language processing. Language dominance is able to be evaluated using laterality of power attenuation in the low γ band in the frontal area. Neuromagnetic signals of the unilateral upper movements are able to be decoded using a support vector machine.

  • ATTI: Workload-Aware Query Adaptive OcTree Based Trajectory Index

    Xiangxu MENG  Xiaodong WANG  Xinye LIN  

     
    PAPER-Data Engineering, Web Information Systems

      Vol:
    E96-D No:3
      Page(s):
    643-654

    The GPS trajectory databases serve as bases for many intelligent applications that need to extract some trajectories for future processing or mining. When doing such tasks, spatio-temporal range queries based methods, which find all sub-trajectories within the given spatial extent and time interval, are commonly used. However, the history trajectory indexes of such methods suffer from two problems. First, temporal and spatial factors are not considered simutaneously, resulting in low performance when processing spatio-temporal queries. Second, the efficiency of indexes is sensitive to query size. The query performance changes dramatically as the query size changed. This paper proposes workload-aware Adaptive OcTree based Trajectory clustering Index (ATTI) aiming at optimizing trajectory storage and index performance. The contributions are three-folds. First, the distribution and time delay of the trajectory storage are introduced into the cost model of spatio-temporal range query; Second, the distribution of spatial division is dynamically adjusted based on GPS update workload; Third, the query workload adaptive mechanism is proposed based on virtual OcTree forest. A wide range of experiments are carried out over Microsoft GeoLife project dataset, and the results show that query delay of ATTI could be about 50% shorter than that of the nested index.

  • VHF Radio Wave Observations by Maido-1 Satellite and Evaluation of Its Relationship with Lightning Discharges

    Hiroshi KIKUCHI  Satoru YOSHIDA  Takeshi MORIMOTO  Tomoo USHIO  Zenichiro KAWASAKI  

     
    PAPER-Sensing

      Vol:
    E96-B No:3
      Page(s):
    880-886

    We examine the relationship between 116 VHF sensor events recorded by the VHF sensor on the Maido-1 satellite and lightning strokes detected by the World Wide Lightning Location Network (WWLLN) to show that most of the VHF sensor events were caused by lightning discharges. For each VHF sensor event, the WWLLN events within 1400 km from the subsatellite point and within 1 sec, 30 sec, and 300 sec of the VHF sensor trigger time are analyzed. We find that the coincidence rates in the North and South American continents, and in Southeast/East Asia and the Australian continent are greater than 0.90. Those in the African and European continents, and in the Pacific and Atlantic Oceans are less than 0.61. These high enough coincidence rates indicate that the VHF sensor events were emitted from lightning, although the coincidence rates in the other regions are quite low because of the low detection efficiency of the WWLLN in the regions. We also focus on 6 coincident events measured by both the VHF sensor and the WWLLN. The incidence angles of the EM waves for the VHF sensor are estimated from the group delay characteristics of the recorded EM waveforms. Compared with the WWLLN lightning locations, the two incidence angles are temporally and spatially coincident. These results indicate that a large fraction of the VHF sensor events are emitted by lightning discharges.

  • Oxidation Time Dependence of Graphene Oxide

    Koichi SAKAGUCHI  Akinori FUJITO  Seiko UCHINO  Asami OHTAKE  Noboru TAKISAWA  Kunio AKEDO  Masanao ERA  

     
    BRIEF PAPER

      Vol:
    E96-C No:3
      Page(s):
    369-371

    We investigated oxidation time dependence of graphene oxide employing modified Hummer method by dynamic light scattering. Oxidation reaction proceeded rapidly within about 24 hours, and was saturated. It is suggested that graphene oxides were not able to freely fragment. This implies that the oxidation reactions occur at the limited sites.

  • An Algorithm for Obtaining the Inverse for a Given Polynomial in Baseband

    Yuelin MA  Yasushi YAMAO  Yoshihiko AKAIWA  

     
    PAPER-Digital Signal Processing

      Vol:
    E96-A No:3
      Page(s):
    675-683

    Compensation for the nonlinear systems represented by polynomials involves polynomial inverse. In this paper, a new algorithm is proposed that gives the baseband polynomial inverse with a limited order. The algorithm employs orthogonal basis that is predetermined from the distribution of input signal and finds the coefficients of the inverse polynomial to minimize the mean square error. Compared with the well established p-th order inverse method, the proposed method can suppress the distortions better including higher order distortions. It is also extended to obtain memory polynomial inverse through a feedback-configured structure. Both numerical simulations and experimental results demonstrate that the proposed algorithm can provide good performance for compensating the nonlinear systems represented by baseband polynomials.

  • Collision Probability in an In-Line Equipment Model under Erlang Distribution

    Eishi CHIBA  Hiroshi FUJIWARA  Yoshiyuki SEKIGUCHI  Toshihide IBARAKI  

     
    PAPER

      Vol:
    E96-D No:3
      Page(s):
    400-407

    Flat Panel Displays (FPDs) are manufactured using many pieces of different processing equipment arranged sequentially in a line. Although the constant inter-arrival time (i.e., the tact time) of glass substrates in the line should be kept as short as possible, the collision probability between glass substrates increases as tact time decreases. Since the glass substrate is expensive and fragile, collisions should be avoided. In this paper, we derive a closed form formula of the approximate collision probability for a model, in which the processing time on each piece of equipment is assumed to follow Erlang distribution. We also compare some numerical results of the closed form and computer simulation results of the collision probability.

  • Interactive Evolutionary Computation Using a Tabu Search Algorithm

    Hiroshi TAKENOUCHI  Masataka TOKUMARU  Noriaki MURANAKA  

     
    PAPER-Human-computer Interaction

      Vol:
    E96-D No:3
      Page(s):
    673-680

    We present an Interactive Tabu Search (ITS) algorithm to reduce the evaluation load of Interactive Evolutionary Computation (IEC) users. Most previous IEC studies used an evaluation interface that required users to provide evaluation values for all candidate solutions. However, user's burden with such an evaluation interface is large. Therefore, we propose ITS where users choose the favorite candidate solution from the presented candidate solutions. Tabu Search (TS) is recognized as an optimization technique. ITS evaluation is simpler than Interactive Genetic Algorithm (IGA) evaluation, in which users provide evaluation values for all candidate solutions. Therefore, ITS is effective for reducing user evaluation load. We evaluated the performance of our proposed ITS and a Normal IGA (NIGA), which is a conventional 10-stage evaluation, using a numerical simulation with an evaluation agent that imitates human preferences (Kansei). In addition, we implemented an ITS evaluation for a running-shoes-design system and examined its effectiveness through an experiment with real users. The simulation results showed that the evolution performance of ITS is better than that of NIGA. In addition, we conducted an evaluation experiment with 21 subjects in their 20 s to assess the effectiveness of these methods. The results showed that the satisfaction levels for the candidates generated by ITS and NIGA were approximately equal. Moreover, it was easier for test subjects to evaluate candidate solutions with ITS than with NIGA.

  • Improvement of Adhesion Strength of Fluoropolymer Thin Films by Vapor Deposition Polymerization

    Kazuo SENDA  Tsuyoshi MATSUDA  Kuniaki TANAKA  Hiroaki USUI  

     
    BRIEF PAPER

      Vol:
    E96-C No:3
      Page(s):
    374-377

    Fluoropolymer thin films were prepared by the ion-assisted vapor deposition polymerization (IAD) of 2-(perfluorohexyl)ethylacrylate (Rf-6). The adhesion strength of the film to substrates was estimated by sonicating the films in water and by immersing the films into dichloro-pentafluoro propane (HCFC225). The Rf-6 polymer films by IAD showed stronger adhesion to glass compared to a spin-coated Teflon AF film. The adhesion strength was improved with increasing ion energy Eion of IAD. The IAD films showed superior adhesion to PET surface compared to the glass substrate. The Rf-6 polymer film was effective as a single-layer antireflective coating. The refractive index of the film was 1.368 (λ = 546 nm), which increased slightly with increasing Eion. IAD can be a promising method to prepare fluoropolymer thin films due to the solvent-less process and the flexibility in controlling the film characteristics by the ion energy.

  • Design of the Start-Frame-Delimiter Pair for 802.15 Smart Utility Network System

    Liru LU  Hiroshi HARADA  Ryuhei FUNADA  Chin-Sean SUM  

     
    PAPER-Transmission Systems and Transmission Equipment for Communications

      Vol:
    E96-B No:3
      Page(s):
    730-736

    The Start-frame-delimiter (SFD) is crucial in packet-based communications system since it indicates the end of preamble and the start of a frame. In 802.15 smart utility network system, the function of SFD is extended. Two different SFDs are used for achieving frame synchronization and at the same time, to differentiate coded and uncoded packets. This paper proposes a systematic method for the selection of SFD pair for FSK based systems. The design method is adopted by 802.15.4g Task Group with the backward compatibility to IEEE 802.15.4d systems taken into account. Four selection criteria are specified and discussed to determine the pair of sequences providing least packet error detection rate with the consideration of eliminating the adjacent channel image signal commonly occurred in the low IF receiver. The probability of false alarm and miss detection is analyzed to verify the effectiveness of the proposed selection method. The simulation results confirm that error frame detection rate of 1e-3 can be achieved with selected SFD sequences. The proposed method for selection of SFD pairs ensures a robust packet header and thus better payload protection. The SFD design approach is applicable to other packet-based wireless communication FSK systems with the support of more than one SFD sequence.

  • Energy- and Traffic-Balance-Aware Mapping Algorithm for Network-on-Chip

    Zhi DENG  Huaxi GU  Yingtang YANG  Hua YOU  

     
    LETTER-Computer System

      Vol:
    E96-D No:3
      Page(s):
    719-722

    In this paper, an energy- and traffic-balance-aware mapping algorithm from IP cores to nodes in a network is proposed for application-specific Network-on-Chip(NoC). The multi-objective optimization model is set up by considering the NoC architecture, and addressed by the proposed mapping algorithm that decomposes mapping optimization into a number of scalar subproblems simultaneously. In order to show performance of the proposed algorithm, the application specific benchmark is applied in the simulation. The experimental results demonstrate that the algorithm has advantages in energy consumption and traffic balance over other algorithms.

  • Exact Algorithms for Annotated Edge Dominating Set in Graphs with Degree Bounded by 3

    Mingyu XIAO  Hiroshi NAGAMOCHI  

     
    PAPER

      Vol:
    E96-D No:3
      Page(s):
    408-418

    Given a graph G = (V,E) together with a nonnegative integer requirement on vertices r:V Z+, the annotated edge dominating set problem is to find a minimum set M ⊆ E such that, each edge in E - M is adjacent to some edge in M, and M contains at least r(v) edges incident on each vertex v ∈ V. The annotated edge dominating set problem is a natural extension of the classical edge dominating set problem, in which the requirement on vertices is zero. The edge dominating set problem is an important graph problem and has been extensively studied. It is well known that the problem is NP-hard, even when the graph is restricted to a planar or bipartite graph with maximum degree 3. In this paper, we show that the annotated edge dominating set problem in graphs with maximum degree 3 can be solved in O*(1.2721n) time and polynomial space, where n is the number of vertices in the graph. We also show that there is an O*(2.2306k)-time polynomial-space algorithm to decide whether a graph with maximum degree 3 has an annotated edge dominating set of size k or not.

  • Computational Models of Human Visual Attention and Their Implementations: A Survey Open Access

    Akisato KIMURA  Ryo YONETANI  Takatsugu HIRAYAMA  

     
    INVITED SURVEY PAPER

      Vol:
    E96-D No:3
      Page(s):
    562-578

    We humans are easily able to instantaneously detect the regions in a visual scene that are most likely to contain something of interest. Exploiting this pre-selection mechanism called visual attention for image and video processing systems would make them more sophisticated and therefore more useful. This paper briefly describes various computational models of human visual attention and their development, as well as related psychophysical findings. In particular, our objective is to carefully distinguish several types of studies related to human visual attention and saliency as a measure of attentiveness, and to provide a taxonomy from several viewpoints such as the main objective, the use of additional cues and mathematical principles. This survey finally discusses possible future directions for research into human visual attention and saliency computation.

  • Proportionally Quasi-Fair Scheduling for End-to-End Rates in Multi-Hop Wireless Networks

    Dang-Quang BUI  Won-Joo HWANG  

     
    PAPER-Wireless Communication Technologies

      Vol:
    E96-B No:3
      Page(s):
    820-829

    Known an a criterion that solves the trade-off between fairness and efficiency, proportional fairness is well-studied in cellular networks in the Qualcomm High Data Rate System. In multi-hop wireless networks, proportional fairness is solved by maximizing the logarithmic aggregate utility function. However, this approach can deal with instantaneous rates only where long term fairness is to be targeted. In this case, cumulative rates are more suitable. This paper proposes a framework for multi-hop wireless networks to guarantee fairness of cumulative data rates. The framework can be extended to other kinds of fairness such as max-min fairness, and to more complex networks, multi-channel multi-radio wireless networks.

  • Adaptive Iterative Decoding of Finite-Length Differentially Encoded LDPC Coded Systems with Multiple-Symbol Differential Detection

    Yang YU  Shiro HANDA  Fumihito SASAMORI  Osamu TAKYU  

     
    PAPER-Wireless Communication Technologies

      Vol:
    E96-B No:3
      Page(s):
    847-858

    In this paper, through extrinsic information transfer (EXIT) band chart analysis, an adaptive iterative decoding approach (AIDA) is proposed to reduce the iterative decoding complexity and delay for finite-length differentially encoded Low-density parity-check (DE-LDPC) coded systems with multiple-symbol differential detection (MSDD). The proposed AIDA can adaptively adjust the observation window size (OWS) of the MSDD soft-input soft-output demodulator (SISOD) and the outer iteration number of the iterative decoder (consisting of the MSDD SISOD and the LDPC decoder) instead of setting fixed values for the two parameters of the considered systems. The performance of AIDA depends on its stopping criterion (SC) which is used to terminate the iterative decoding before reaching the maximum outer iteration number. Many SCs have been proposed; however, these approaches focus on turbo coded systems, and it has been proven that they do not well suit for LDPC coded systems. To solve this problem, a new SC called differential mutual information (DMI) criterion, which can track the convergence status of the iterative decoding, is proposed; it is based on tracking the difference of the output mutual information of the LDPC decoder between two consecutive outer iterations of the considered systems. AIDA using the DMI criterion can adaptively adjust the out iteration number and OWS according to the convergence situation of the iterative decoding. Simulation results show that compared with using the existing SCs, AIDA using the DMI criterion can further reduce the decoding complexity and delay, and its performance is not affected by a change in the LDPC code and transmission channel parameters.

  • Risk Assessment of a Portfolio Selection Model Based on a Fuzzy Statistical Test

    Pei-Chun LIN  Junzo WATADA  Berlin WU  

     
    PAPER-Fundamentals of Information Systems

      Vol:
    E96-D No:3
      Page(s):
    579-588

    The objective of our research is to build a statistical test that can evaluate different risks of a portfolio selection model with fuzzy data. The central points and radiuses of fuzzy numbers are used to determine the portfolio selection model, and we statistically evaluate the best return by a fuzzy statistical test. Empirical studies are presented to illustrate the risk evaluation of the portfolio selection model with interval values. We conclude that the fuzzy statistical test enables us to evaluate a stable expected return and low risk investment with different choices for k, which indicates the risk level. The results of numerical examples show that our method is suitable for short-term investments.

  • Orientation Imaging of Single Molecule at Various Ambient Conditions

    Toshiki YAMADA  Takahiro KAJI  Akira OTOMO  

     
    BRIEF PAPER

      Vol:
    E96-C No:3
      Page(s):
    381-382

    After brief introduction of our new microscope unit with an immersion objective and ionic liquid used as a refractive index matching medium, in this paper, we describe the studies on dipole orientation imaging of single molecules under high vacuum conditions as one of the important applications of our microscope.

  • Linear Time Algorithms for Finding Articulation and Hinge Vertices of Circular Permutation Graphs

    Hirotoshi HONMA  Kodai ABE  Yoko NAKAJIMA  Shigeru MASUYAMA  

     
    PAPER

      Vol:
    E96-D No:3
      Page(s):
    419-425

    Let Gs=(Vs, Es) be a simple connected graph. A vertex v ∈ Vs is an articulation vertex if deletion of v and its incident edges from Gs disconnects the graph into at least two connected components. Finding all articulation vertices of a given graph is called the articulation vertex problem. A vertex u ∈ Vs is called a hinge vertex if there exist any two vertices x and y in Gs whose distance increase when u is removed. Finding all hinge vertices of a given graph is called the hinge vertex problem. These problems can be applied to improve the stability and robustness of communication network systems. In this paper, we propose linear time algorithms for the articulation vertex problem and the hinge vertex problem of circular permutation graphs.

  • Reconstruction Algorithms for Permutation Graphs and Distance-Hereditary Graphs

    Masashi KIYOMI  Toshiki SAITOH  Ryuhei UEHARA  

     
    PAPER

      Vol:
    E96-D No:3
      Page(s):
    426-432

    PREIMAGE CONSTRUCTION problem by Kratsch and Hemaspaandra naturally arose from the famous graph reconstruction conjecture. It deals with the algorithmic aspects of the conjecture. We present an O(n8) time algorithm for PREIMAGE CONSTRUCTION on permutation graphs and an O(n4(n+m)) time algorithm for PREIMAGE CONSTRUCTION on distance-hereditary graphs, where n is the number of graphs in the input, and m is the number of edges in a preimage. Since each graph of the input has n-1 vertices and O(n2) edges, the input size is O(n3) (, or O(nm)). There are polynomial time isomorphism algorithms for permutation graphs and distance-hereditary graphs. However the number of permutation (distance-hereditary) graphs obtained by adding a vertex to a permutation (distance-hereditary) graph is generally exponentially large. Thus exhaustive checking of these graphs does not achieve any polynomial time algorithm. Therefore reducing the number of preimage candidates is the key point.

  • A Fast Implementation of PCA-L1 Using Gram-Schmidt Orthogonalization

    Mariko HIROKAWA  Yoshimitsu KUROKI  

     
    LETTER-Face Perception and Recognition

      Vol:
    E96-D No:3
      Page(s):
    559-561

    PCA-L1 (principal component analysis based on L1-norm maximization) is an approximate solution of L1-PCA (PCA based on the L1-norm), and has robustness against outliers compared with traditional PCA. However, the more dimensions the feature space has, the more calculation time PCA-L1 consumes. This paper focuses on an initialization procedure of PCA-L1 algorithm, and proposes a fast method of PCA-L1 using Gram-Schmidt orthogonalization. Experimental results on face recognition show that the proposed method works faster than conventional PCA-L1 without decrease of recognition accuracy.

5701-5720hit(18690hit)