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281-300hit(1110hit)

  • Ontology Based Framework for Interactive Self-Assessment of e-Health Applications Open Access

    Wasin PASSORNPAKORN  Sinchai KAMOLPHIWONG  

     
    INVITED PAPER

      Pubricized:
    2015/10/21
      Vol:
    E99-D No:1
      Page(s):
    2-9

    Personal e-healthcare service is growing significantly. A large number of personal e-health measuring and monitoring devices are now in the market. However, to achieve better health outcome, various devices or services need to work together. This coordination among services remains challenge, due to their variations and complexities. To address this issue, we have proposed an ontology-based framework for interactive self-assessment of RESTful e-health services. Unlike existing e-health service frameworks where they had tightly coupling between services, as well as their data schemas were difficult to change and extend in the future. In our work, the loosely coupling among services and flexibility of each service are achieved through the design and implementation based on HYDRA vocabulary and REST principles. We have implemented clinical knowledge through the combination of OWL-DL and SPARQL rules. All of these services evolve independently; their interfaces are based on REST principles, especially HATEOAS constraints. We have demonstrated how to apply our framework for interactive self-assessment in e-health applications. We have shown that it allows the medical knowledge to drive the system workflow according to the event-driven principles. New data schema can be maintained during run-time. This is the essential feature to support arriving of IoT (Internet of Things) based medical devices, which have their own data schema and evolve overtime.

  • Towards Position-Aware Symbol-Based Searches on Encrypted Data from Symmetric Predicate Encryption Schemes

    Fu-Kuo TSENG  Rong-Jaye CHEN  

     
    LETTER-Cryptography and Information Security

      Vol:
    E99-A No:1
      Page(s):
    426-428

    Symmetric predicate encryption schemes support a rich class of predicates over keyword ciphertexts while preserving both keyword privacy and predicate privacy. Most of these schemes treat each keyword as the smallest unit to be processed in the generation of ciphertexts and predicate tokens. To extend the class of predicates, we treat each symbol of a keyword as the smallest unit to be processed. In this letter, we propose a novel encoding to construct a symmetric inner-product encryption scheme for position-aware symbol-based predicates. The resulting scheme can be applied to a number of secure filtering and online storage services.

  • Millimeter-Wave Broadband Mode Transition between Grounded Coplanar Waveguide and Post-Wall Waveguide

    Ryohei HOSONO  Yusuke UEMICHI  Xu HAN  Ning GUAN  Yusuke NAKATANI  

     
    PAPER-Antennas and Propagation

      Vol:
    E99-B No:1
      Page(s):
    33-39

    A broadband mode transition between grounded coplanar waveguide (GCPW) and post-wall waveguide (PWW) is proposed. The transition is composed of GCPW, microstrip line (MSL) and PWW, where the GCPW and PWW are connected via the MSL. The transition is fabricated on liquid crystal polymer (LCP) substrate because of its low dielectric loss and cost effectiveness based on a roll-to-roll fabrication process. Center strip of the GCPW is sandwiched by two ground pads in each of which two through-holes and a rectangular slit are structured. Broadband impedance matching is achieved by this structure thanks to an addition of lumped inductance and capacitance to the transition. A part of the MSL is tapered for the broadband operation. A 25% impedance bandwidth for |S11| less than -15dB is achieved in measurement of a fabricated transition. Loss of the GCPW ground-signal-ground (GSG) pad of 0.12dB and that of the MSL-PWW transition of 0.29dB at 60GHz are evaluated from the measurement. Fabrication error and the caused tolerance on performance are also evaluated and small variation in production is confirmed. The mode transition can be used for low loss antenna-in-package in millimeter-wave applications.

  • Improving Performance of DS/SS-IVC Scheme Based on Location Oriented PN Code Allocation

    Reiki KUSAKARI  Akira NAKAMURA  Kohei OHNO  Makoto ITAMI  

     
    PAPER

      Vol:
    E99-A No:1
      Page(s):
    225-234

    Currently, IEEE802.11p and ARIB STD T-109 are available as the typical inter-vehicle communication (IVC) standards. Carrier sense multiple access/collision avoidance (CSMA/CA) and orthogonal frequency division multiplexing (OFDM) are used in these standards. However, the performance degrades when there are hidden terminals. In this paper, IVC system that using a direct sequence spread spectrum (DS/SS) modulation scheme is discussed because it has code division multiple access (CDMA) capability. In DS/SS-IVC scheme, it is possible to avoid hidden terminal problem. On the other hand, near-far problem (NFP), multiple access interference (MAI) and interference by equivalent pseudo noise (PN) codes occurs in DS/SS communication. These problems cause performance degradation. In this paper, interference cancellation scheme and slotted ALOHA scheme with code sensing are applied so as to mitigate the impact of MAI, NFP and interference by equivalent PN code. By applying interference cancellation scheme and slotted ALOHA scheme with code sensing, the performance of DS/SS-IVC is improved. In this paper, location oriented PN code allocation is focused on as a method of PN code assignment. However, DS/SS-IVC scheme based on location oriented PN code allocation has a problem. Since each vehicle obtain PN code based on the position that is estimated by GPS, performance degrades when GPS positioning error occurs. Therefore, the positioning system of DS/SS-IVC scheme is also discussed in this paper. Elimination of ranging data that has large ranging error is proposed in addition to interference cancellation scheme and slotted ALOHA scheme with code sensing in order to improve the performance of positioning. From the simulation results, the positioning error can be mitigated by applying these proposed techniques.

  • Postcopy Live Migration with Guest-Cooperative Page Faults

    Takahiro HIROFUCHI  Isaku YAMAHATA  Satoshi ITOH  

     
    PAPER-Operating System

      Pubricized:
    2015/09/15
      Vol:
    E98-D No:12
      Page(s):
    2159-2167

    Postcopy live migration is a promising alternative of virtual machine (VM) migration, which transfers memory pages after switching the execution host of a VM. It allows a shorter and more deterministic migration time than precopy migration. There is, however, a possibility that postcopy migration would degrade VM performance just after switching the execution host. In this paper, we propose a performance improvement technique of postcopy migration, extending the para-virtualized page fault mechanism of a virtual machine monitor. When the guest operating system accesses a not-yet-transferred memory page, our proposed mechanism allows the guest kernel to defer the execution of the current process until the page data is transferred. In parallel with the page transfer, the guest kernel can yield VCPU to other active processes. We implemented the proposed technique in our postcopy migration mechanism for Qemu/KVM. Through experiments, we confirmed that our technique successfully alleviated performance degradation of postcopy migration for web server and database benchmarks.

  • Magnetic Field Measurement for Human Exposure Assessment near Wireless Power Transfer Systems in Kilohertz and Megahertz Bands

    Satoshi ISHIHARA  Teruo ONISHI  Akimasa HIRATA  

     
    PAPER-Electromagnetic Compatibility(EMC)

      Vol:
    E98-B No:12
      Page(s):
    2470-2476

    A method for measuring the magnetic field strength for human exposure assessment closer than 20cm to wireless power transfer (WPT) systems for information household appliances is investigated based on numerical simulations and measurements at 100kHz and 6.78MHz. Four types of magnetic sources are considered: a simple 1-turn coil and three types of coils simulating actual WPT systems. A magnetic sensor whose cross sectional area is 100cm2 as prescribed in International Electrotechnical Commission 62233 is used. Simulation results show that the magnetic field strength detected by the magnetic sensor is affected by its placement angle. The maximum coefficient of variation (CV) is 27.2% when the magnetic source and the sensor are in contact. The reason for this deviation is attributable to the localization of the magnetic field distribution around the magnetic source. The coupling effect between the magnetic source and the sensor is negligible. Therefore, the sensor placement angle is an essential factor in magnetic field measurements. The CV due to the sensor placement angle is reduced from 21% to 4% if the area of the sensor coil is reduced from 100 to 0.75cm2 at 6.78MHz. However, the sensitivity of the sensor coil is decreased by 42.5dB. If measurement uncertainty that considers the deviation in the magnetic field strength due to the sensor placement angle is large, the measured magnetic field strength should be corrected by the uncertainty. If the magnetic field distribution around the magnetic source is known, conservative exposure assessments can be achieved by placing the magnetic sensor in locations at which the spatial averaged magnetic field strengths perpendicular to the magnetic sensor coils become maximum.

  • A Length Matching Routing Algorithm for Set-Pair Routing Problem

    Yuta NAKATANI  Atsushi TAKAHASHI  

     
    PAPER-Physical Level Design

      Vol:
    E98-A No:12
      Page(s):
    2565-2571

    In the routing design of interposer and etc., the combination of a pin pair to be connected by wire is often flexible, and the reductions of the total wire length and the length difference are pursued to keep the circuit performance. Even though the total wire length can be minimized by finding a minimum cost maximum flow in set pair routing problems, the length difference is often large, and the reduction of it is not easy. In this paper, an algorithm that reduces the length difference while keeping the total wire length small is proposed. In the proposed algorithm, an initial routing first obtained by a minimum cost maximum flow. Then it is modified to reduce the maximum length while keeping the minimum total wire length, and a connection of the minimum length is detoured to reduce the length difference. The effectiveness of the proposed algorithm is confirmed by experiments.

  • Top (k1,k2) Query in Uncertain Datasets

    Fei LIU  Jiarun LIN  Yan JIA  

     
    LETTER-Artificial Intelligence, Data Mining

      Pubricized:
    2015/07/22
      Vol:
    E98-D No:11
      Page(s):
    1998-2002

    In this letter, we propose a novel kind of uncertain query, top (k1,k2) query. The x-tuple model and the possible world semantics are used to describe data objects in uncertain datasets. The top (k1,k2) query is going to find k2 x-tuples with largest probabilities to be the result of top k1 query in a possible world. Firstly, we design a basic algorithm for top (k1,k2) query based on dynamic programming. And then some pruning strategies are designed to improve its efficiency. An improved initialization method is proposed for further acceleration. Experiments in real and synthetic datasets prove the performance of our methods.

  • Transparent Organic Light-Emitting Diodes with Top Electrode Using Ion-Plating Method

    Hironao SANO  Ryota ISHIDA  Tatsuya KURA  Shunsuke FUJITA  Shigeki NAKA  Hiroyuki OKADA  Takeshi TAKAI  

     
    BRIEF PAPER

      Vol:
    E98-C No:11
      Page(s):
    1035-1038

    Transparent organic light-emitting diodes (TOLEDs) were investigated with top electrode of indium-tin-oxide (ITO) by ion-plating method. High deposition rate of 4.4 nm/s was realized without plasma damage of under organic layer. In the TOLEDs with inverted structure, high transmittance of over 75% at 550 nm and bright emission of 1,850 and 1,410 cd/m2, from bottom and top side at 163 mA/cm2, respectively, were obtained.

  • An Efficient and Universal Conical Hypervolume Evolutionary Algorithm in Three or Higher Dimensional Objective Space

    Weiqin YING  Yuehong XIE  Xing XU  Yu WU  An XU  Zhenyu WANG  

     
    LETTER-Numerical Analysis and Optimization

      Vol:
    E98-A No:11
      Page(s):
    2330-2335

    The conical area evolutionary algorithm (CAEA) has a very high run-time efficiency for bi-objective optimization, but it can not tackle problems with more than two objectives. In this letter, a conical hypervolume evolutionary algorithm (CHEA) is proposed to extend the CAEA to a higher dimensional objective space. CHEA partitions objective spaces into a series of conical subregions and retains only one elitist individual for every subregion within a compact elitist archive. Additionally, each offspring needs to be compared only with the elitist individual in the same subregion in terms of the local hypervolume scalar indicator. Experimental results on 5-objective test problems have revealed that CHEA can obtain the satisfactory overall performance on both run-time efficiency and solution quality.

  • Posteriori Restoration of Turn-Taking and ASR Results for Incorrectly Segmented Utterances

    Kazunori KOMATANI  Naoki HOTTA  Satoshi SATO  Mikio NAKANO  

     
    PAPER-Speech and Hearing

      Pubricized:
    2015/07/24
      Vol:
    E98-D No:11
      Page(s):
    1923-1931

    Appropriate turn-taking is important in spoken dialogue systems as well as generating correct responses. Especially if the dialogue features quick responses, a user utterance is often incorrectly segmented due to short pauses within it by voice activity detection (VAD). Incorrectly segmented utterances cause problems both in the automatic speech recognition (ASR) results and turn-taking: i.e., an incorrect VAD result leads to ASR errors and causes the system to start responding though the user is still speaking. We develop a method that performs a posteriori restoration for incorrectly segmented utterances and implement it as a plug-in for the MMDAgent open-source software. A crucial part of the method is to classify whether the restoration is required or not. We cast it as a binary classification problem of detecting originally single utterances from pairs of utterance fragments. Various features are used representing timing, prosody, and ASR result information. Experiments show that the proposed method outperformed a baseline with manually-selected features by 4.8% and 3.9% in cross-domain evaluations with two domains. More detailed analysis revealed that the dominant and domain-independent features were utterance intervals and results from the Gaussian mixture model (GMM).

  • Matrix Approach for the Seasonal Infectious Disease Spread Prediction

    Hideo HIROSE  Masakazu TOKUNAGA  Takenori SAKUMURA  Junaida SULAIMAN  Herdianti DARWIS  

     
    PAPER

      Vol:
    E98-A No:10
      Page(s):
    2010-2017

    Prediction of seasonal infectious disease spread is traditionally dealt with as a function of time. Typical methods are time series analysis such as ARIMA (autoregressive, integrated, and moving average) or ANN (artificial neural networks). However, if we regard the time series data as the matrix form, e.g., consisting of yearly magnitude in row and weekly trend in column, we may expect to use a different method (matrix approach) to predict the disease spread when seasonality is dominant. The MD (matrix decomposition) method is the one method which is used in recommendation systems. The other is the IRT (item response theory) used in ability evaluation systems. In this paper, we apply these two methods to predict the disease spread in the case of infectious gastroenteritis caused by norovirus in Japan, and compare the results obtained by using two conventional methods in forecasting, ARIMA and ANN. We have found that the matrix approach is simple and useful in prediction for the seasonal infectious disease spread.

  • The Wear of Hot Switching Au/Cr-Au/MWCNT Contact Pairs for MEMS Contacts

    John W. McBRIDE  Hong LIU  Chamaporn CHIANRABUTRA  Adam P. LEWIS  

     
    PAPER

      Vol:
    E98-C No:9
      Page(s):
    912-918

    A gold coated carbon nanotubes composite was used as a contact material in Micro-Electrical-Mechanical-System (MEMS) switches. The switching contact was tested under typical conditions of MEMS relay applications: load voltage of 4 V, contact force of 1 mN, and load current varied between 20-200 mA. This paper focuses on the wear process over switching lifetime, and the dependence of the wear area on the current is discussed. It was shown that the contact was going to fail when the wear area approached the whole contact area, at which point the contact resistance increased sharply to three times the nominal resistance.

  • A Realization of Signal-Model-Based SAR Imaging via Atomic Decomposition

    Yesheng GAO  Hui SHENG  Kaizhi WANG  Xingzhao LIU  

     
    PAPER-Digital Signal Processing

      Vol:
    E98-A No:9
      Page(s):
    1906-1913

    A signal-model-based SAR image formation algorithm is proposed in this paper. A model is used to describe the received signal, and each scatterer can be characterized by a set of its parameters. Two parameter estimation methods via atomic decomposition are presented: (1) applying 1-D matching pursuit to azimuthal projection data; (2) applying 2-D matching pursuit to raw data. The estimated parameters are mapped to form a SAR image, and the mapping procedure can be implemented under application guidelines. This algorithm requires no prior information about the relative motion between the platform and the target. The Cramer-Rao bounds of parameter estimation are derived, and the root mean square errors of the estimates are close to the bounds. Experimental results are given to validate the algorithm and indicate its potential applications.

  • A New Method for Evaluation of Positioning Accuracy in the Semantic Space

    Luka VIDMAR  Marko PESKO  Mitja ŠTULAR  Blaž PETERNEL  Andrej KOS  Matevž POGAČNIK  

     
    PAPER-Sensing

      Vol:
    E98-B No:9
      Page(s):
    1906-1913

    User context and user location in particular play an important role in location-based services (LBS). The location can be determined by various positioning methods. These are typically evaluated with average positioning error or percentile values, which are not the most suitable metrics for evaluation of how a positioning method functions in the semantic space. Therefore, we propose a new method for evaluation of positioning accuracy in the semantic space. We focus on two types of semantic user locations that are widely available in urban areas: the street address and the categories of the surrounding points of interest (POIs). We demonstrate its use on ten different positioning methods: a standalone satellite navigation device, GPS module on a smartphone, two versions of Foursquare positioning service, Google positioning service, a positioning service of the local mobile operator, and four other possible variants of mobile operator-based positioning methods. The evaluation suggests that approach with the street addresses is more promising approach due to either sparse or unevenly distributed POIs. Furthermore, some of the positioning methods that are less accurate in Euclidean space, such as a combination of the GPS data with the mobile operator-based method that relies on the propagation models, performed comparably well in the semantic space as the methods that are using more accurate technologies, such as Google and Foursquare.

  • Non-Orthogonal Multiple Access Using Intra-Beam Superposition Coding and SIC in Base Station Cooperative MIMO Cellular Downlink

    Nobuhide NONAKA  Yoshihisa KISHIYAMA  Kenichi HIGUCHI  

     
    PAPER-Wireless Communication Technologies

      Vol:
    E98-B No:8
      Page(s):
    1651-1659

    This paper extends our previously proposed non-orthogonal multiple access (NOMA) scheme to the base station (BS) cooperative multiple-input multiple-output (MIMO) cellular downlink for future radio access. The proposed NOMA scheme employs intra-beam superposition coding of a multiuser signal at the transmitter and the spatial filtering of inter-beam interference followed by the intra-beam successive interference canceller (SIC) at the user terminal receiver. The intra-beam SIC cancels out the inter-user interference within a beam. This configuration achieves reduced overhead for the downlink reference signaling for channel estimation at the user terminal in the case of non-orthogonal user multiplexing and enables the use of the SIC receiver in the MIMO downlink. The transmitter beamforming (precoding) matrix is controlled based on open loop-type random beamforming using a block-diagonalized beamforming matrix, which is very efficient in terms of the amount of feedback information from the user terminal. Simulation results show that the proposed NOMA scheme with block-diagonalized random beamforming in BS cooperative multiuser MIMO and the intra-beam SIC achieves better system-level throughput than orthogonal multiple access (OMA), which is assumed in LTE-Advanced. We also show that BS cooperative operation along with the proposed NOMA further enhances the cell-edge user throughput gain which implies better user fairness and universal connectivity.

  • Constrained Weighted Least Square Filter for Chrominance Recovery of High Resolution Compressed Image

    Takamichi MIYATA  Tomonobu YOSHINO  Sei NAITO  

     
    PAPER

      Vol:
    E98-A No:8
      Page(s):
    1718-1726

    Ultra high definition (UHD) imaging systems have attracted much attention as a next generation television (TV) broadcasting service and video streaming service. However, the state of the art video coding standards including H.265/HEVC has not enough compression rate for streaming, broadcasting and storing UHD. Existing coding standard such as H.265/HEVC normaly use RGB-YCbCr color transform before compressing RGB color image since that procedure can decorrelate color components well. However, there is room for improvement on the coding efficiency for color image based on an observation that the luminance and chrominance components changes in same locations. This observation inspired us to propose a new post-processing method for compressed images by using weighted least square (WLS) filter with coded luminance component as a guide image, for refining the edges of chrominance components. Since the computational cost of WLS tends to superlinearly increase with increasing image size, it is difficult to apply it to UHD images. To overcome this problem, we propose slightly overlapped block partitioning and a new variant of WLS (constrained WLS, CWLS). Experimental results of objective quality comparison and subjective assessment test using 4K images show that our proposed method can outperform the conventional method and reduce the bit amount for chrominance component drastically with preserving the subjective quality.

  • Downlink Non-Orthogonal Multiple Access (NOMA) Combined with Single User MIMO (SU-MIMO)

    Anass BENJEBBOUR  Anxin LI  Keisuke SAITO  Yoshihisa KISHIYAMA  Takehiro NAKAMURA  

     
    PAPER

      Vol:
    E98-B No:8
      Page(s):
    1415-1425

    This paper investigates a downlink non-orthogonal multiple access (NOMA) combined with single user MIMO (SU-MIMO) for future LTE (Long-Term Evolution) enhancements. In particular, we propose practical schemes to efficiently combine NOMA with open-loop SU-MIMO (Transmission Mode 3: TM3) and closed-loop SU-MIMO (Transmission Mode 4: TM4) specified in LTE. The goal is also to clarify the performance gains of NOMA combined with SU-MIMO transmission, taking into account the LTE radio interface such as frequency-domain scheduling, adaptive modulation and coding (AMC), and NOMA specific functionalities such as, multi-user pairing/ordering, transmit power allocation and successive interference cancellation (SIC) at the receiver side. Based on computer simulations, we evaluate NOMA link-level performance and show that the impact of error propagation associated with SIC is marginal when the power ratio of cell-edge and cell-center users is sufficiently large. In addition, we evaluate NOMA system-level performance gains for different granularities of scheduling and MCS (modulation and coding scheme) selection, for both genie-aided channel quality information (CQI) estimation and approximated CQI estimation, and using different number of power sets. Evaluation results show that NOMA combined with SU-MIMO can still provide a hefty portion of its expected gains even with approximated CQI estimation and limited number of power sets, and also when LTE compliant subband scheduling and wideband MCS is applied.

  • White Balancing by Using Multiple Images via Intrinsic Image Decomposition

    Ryo MATSUOKA  Tatsuya BABA  Mia RIZKINIA  Masahiro OKUDA  

     
    PAPER-Image Processing and Video Processing

      Pubricized:
    2015/05/14
      Vol:
    E98-D No:8
      Page(s):
    1562-1570

    Using a flash/no-flash image pair, we propose a novel white-balancing technique that can effectively correct the color balance of a complex scene under multiple light sources. In the proposed method, by using multiple images of the same scene taken under different lighting conditions, we estimate the reflectance component of the scene and the multiple shading components of each image. The reflectance component is a specific object color which does not depend on scene illumination and the shading component is a shading effect caused by the illumination lights. Then, we achieve white balancing by appropriately correcting the estimated shading components. The proposed method achieves better performance than conventional methods, especially under colored illumination and mixed lighting conditions.

  • An Evaluation on Two-Handed and One-Handed Control Methods for Positioning Object in Immersive Virtual Environments

    Noritaka OSAWA  Kikuo ASAI  

     
    PAPER-Human-computer Interaction

      Pubricized:
    2015/03/20
      Vol:
    E98-D No:7
      Page(s):
    1316-1324

    A two-handed distance control method is proposed for precisely and efficiently manipulating a virtual 3D object by hand in an immersive virtual reality environment. The proposed method enhances direct manipulation by hand and is used to precisely control and efficiently adjust the position of an object and the viewpoint using the distance between the two hands. The two-handed method is evaluated and compared with the previously proposed one-handed speed control method, which adjusts the position of an object in accordance with the speed of one hand. The results from experimental evaluation show that two-handed methods, which make position and viewpoint adjustments, are the best among six combinations of control and adjustment methods.

281-300hit(1110hit)