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41-60hit(1933hit)

  • Time-Series Prediction Based on Double Pyramid Bidirectional Feature Fusion Mechanism

    Na WANG  Xianglian ZHAO  

     
    PAPER-Digital Signal Processing

      Pubricized:
    2022/12/20
      Vol:
    E106-A No:6
      Page(s):
    886-895

    The application of time-series prediction is very extensive, and it is an important problem across many fields, such as stock prediction, sales prediction, and loan prediction and so on, which play a great value in production and life. It requires that the model can effectively capture the long-term feature dependence between the output and input. Recent studies show that Transformer can improve the prediction ability of time-series. However, Transformer has some problems that make it unable to be directly applied to time-series prediction, such as: (1) Local agnosticism: Self-attention in Transformer is not sensitive to short-term feature dependence, which leads to model anomalies in time-series; (2) Memory bottleneck: The spatial complexity of regular transformation increases twice with the sequence length, making direct modeling of long time-series infeasible. In order to solve these problems, this paper designs an efficient model for long time-series prediction. It is a double pyramid bidirectional feature fusion mechanism network with parallel Temporal Convolution Network (TCN) and FastFormer. This network structure can combine the time series fine-grained information captured by the Temporal Convolution Network with the global interactive information captured by FastFormer, it can well handle the time series prediction problem.

  • Location First Non-Maximum Suppression for Uncovered Muck Truck Detection

    Yuxiang ZHANG  Dehua LIU  Chuanpeng SU  Juncheng LIU  

     
    PAPER-Image

      Pubricized:
    2022/12/13
      Vol:
    E106-A No:6
      Page(s):
    924-931

    Uncovered muck truck detection aims to detect the muck truck and distinguish whether it is covered or not by dust-proof net to trace the source of pollution. Unlike traditional detection problem, recalling all uncovered trucks is more important than accurate locating for pollution traceability. When two objects are very close in an image, the occluded object may not be recalled because the non-maximum suppression (NMS) algorithm can remove the overlapped proposal. To address this issue, we propose a Location First NMS method to match the ground truth boxes and predicted boxes by position rather than class identifier (ID) in the training stage. Firstly, a box matching method is introduced to re-assign the predicted box ID using the closest ground truth one, which can avoid object missing when the IoU of two proposals is greater than the threshold. Secondly, we design a loss function to adapt the proposed algorithm. Thirdly, a uncovered muck truck detection system is designed using the method in a real scene. Experiment results show the effectiveness of the proposed method.

  • Effect of the State of Catalytic Nanoparticles on the Growth of Vertically Aligned Carbon Nanotubes

    Shohei SAKURAI  Mayu IIDA  Kosei OKUNUKI  Masahito KUSHIDA  

     
    PAPER

      Pubricized:
    2023/01/13
      Vol:
    E106-C No:6
      Page(s):
    208-213

    In this study, vertically aligned carbon nanotubes (VA-CNTs) were grown from filler-added LB films with accumulated AlFe2O4 nanoparticles and palmitic acid (C16) as the filler molecule after different hydrogen reduction temperatures of 500°C and 750°C, and the grown VA-CNTs were compared and evaluated. As a result, VA-CNTs were approximately doubled in length after 500°C hydrogen reduction compared to 750°C hydrogen reduction when AlFe2O4 NPs were used. On the other hand, when the catalyst area ratio was decreased by using palmitic acid, i.e., the distance between CNTs was increased, VA-CNTs rapidly shortened after 500°C hydrogen reduction, and VA-CNTs were no longer obtained even in the range where VA-CNTs were obtained in 750°C hydrogen reduction. The inner and outer diameters of VA-CNTs decreased with decreasing catalyst area ratio at 750°C hydrogen reduction and tended to increase at 500°C hydrogen reduction. The morphology of the catalyst nanoparticles after CVD was observed to change significantly depending on the hydrogen reduction temperature and catalyst area ratio. These observations indicate that the state of the catalyst nanoparticles immediately before the CNT growth process greatly affects the physical properties of the CNTs.

  • Lead Bromide-Based Layered Perovskite Quantum-Well Films Having Aromatic Chromophores in Organic Layer

    Masanao ERA  

     
    BRIEF PAPER

      Pubricized:
    2022/12/16
      Vol:
    E106-C No:6
      Page(s):
    244-247

    Lead bromide-based perovskite organic-inorganic quantum-well films incorporated polycyclic aromatic chromophores into the organic layer (in other words, hybrid quantum-wells combined lead bromide semiconductor and organic semiconductors) were prepared by use of the spin-coating technique from the DMF solution in which PbBr2 and alkyl ammonium bromides which were linked polycyclic aromatics, pyrene, phenanthrene, and anthracene. When the pyrene-linked methyl ammonium bromide, which has a relatively small molecular cross-section with regard to the inorganic semiconductor plane, was employed, a lead bromide-based perovskite structure was successfully formed in the spin-coated films. When the phenanthrene-linked and anthracene-linked ammonium bromides, whose chromophore have large molecular cross-sections, were employed, lead bromide-based perovskite structures were not formed. However, the introduction of longer alkyl chains into the aromatics-linked ammonium bromides made it possible to form the perovskite structure.

  • Fixed Point Preserving Model Reduction of Boolean Networks Focusing on Complement and Absorption Laws

    Fuma MOTOYAMA  Koichi KOBAYASHI  Yuh YAMASHITA  

     
    PAPER

      Pubricized:
    2022/10/24
      Vol:
    E106-A No:5
      Page(s):
    721-728

    A Boolean network (BN) is well known as a discrete model for analysis and control of complex networks such as gene regulatory networks. Since complex networks are large-scale in general, it is important to consider model reduction. In this paper, we consider model reduction that the information on fixed points (singleton attractors) is preserved. In model reduction studied here, the interaction graph obtained from a given BN is utilized. In the existing method, the minimum feedback vertex set (FVS) of the interaction graph is focused on. The dimension of the state is reduced to the number of elements of the minimum FVS. In the proposed method, we focus on complement and absorption laws of Boolean functions in substitution operations of a Boolean function into other one. By simplifying Boolean functions, the dimension of the state may be further reduced. Through a numerical example, we present that by the proposed method, the dimension of the state can be reduced for BNs that the dimension of the state cannot be reduced by the existing method.

  • Thermal-Comfort Aware Online Co-Scheduling Framework for HVAC, Battery Systems, and Appliances in Smart Buildings

    Daichi WATARI  Ittetsu TANIGUCHI  Francky CATTHOOR  Charalampos MARANTOS  Kostas SIOZIOS  Elham SHIRAZI  Dimitrios SOUDRIS  Takao ONOYE  

     
    INVITED PAPER

      Pubricized:
    2022/10/24
      Vol:
    E106-A No:5
      Page(s):
    698-706

    Energy management in buildings is vital for reducing electricity costs and maximizing the comfort of occupants. Excess solar generation can be used by combining a battery storage system and a heating, ventilation, and air-conditioning (HVAC) system so that occupants feel comfortable. Despite several studies on the scheduling of appliances, batteries, and HVAC, comprehensive and time scalable approaches are required that integrate such predictive information as renewable generation and thermal comfort. In this paper, we propose an thermal-comfort aware online co-scheduling framework that incorporates optimal energy scheduling and a prediction model of PV generation and thermal comfort with the model predictive control (MPC) approach. We introduce a photovoltaic (PV) energy nowcasting and thermal-comfort-estimation model that provides useful information for optimization. The energy management problem is formulated as three coordinated optimization problems that cover fast and slow time-scales by considering predicted information. This approach reduces the time complexity without a significant negative impact on the result's global nature and its quality. Experimental results show that our proposed framework achieves optimal energy management that takes into account the trade-off between electricity expenses and thermal comfort. Our sensitivity analysis indicates that introducing a battery significantly improves the trade-off relationship.

  • Conflict Reduction of Acyclic Flow Event Structures

    Toshiyuki MIYAMOTO  Marika IZAWA  

     
    PAPER

      Pubricized:
    2022/10/26
      Vol:
    E106-A No:5
      Page(s):
    707-714

    Event structures are a well-known modeling formalism for concurrent systems with causality and conflict relations. The flow event structure (FES) is a variant of event structures, which is a generalization of the prime event structure. In an FES, two events may be in conflict even though they are not syntactically in conflict; this is called a semantic conflict. The existence of semantic conflict in an FES motivates reducing conflict relations (i.e., conflict reduction) to obtain a simpler structure. In this paper, we study conflict reduction in acyclic FESs. A necessary and sufficient condition for conflict reduction is given; algorithms to compute semantic conflict, local configurations, and conflict reduction are proposed. A great time reduction was observed in computational experiments when comparing the proposed with the naive method.

  • Design and Analysis of Si/CaF2 Near-Infrared (λ∼1.7µm) DFB Quantum Cascade Laser for Silicon Photonics

    Gensai TEI  Long LIU  Masahiro WATANABE  

     
    PAPER-Lasers, Quantum Electronics

      Pubricized:
    2022/11/04
      Vol:
    E106-C No:5
      Page(s):
    157-164

    We have designed a near-infrared wavelength Si/CaF2 DFB quantum cascade laser and investigated the possibility of single-mode laser oscillation by analysis of the propagation mode, gain, scattering time of Si quantum well, and threshold current density. As the waveguide and resonator, a slab-type waveguide structure with a Si/CaF2 active layer sandwiched by SiO2 on a Si (111) substrate and a grating structure in an n-Si conducting layer were assumed. From the results of optical propagation mode analysis, by assuming a λ/4-shifted bragg waveguide structure, it was found that the single vertical and horizontal TM mode propagation is possible at the designed wavelength of 1.70µm. In addition, a design of the active layer is proposed and its current injection capability is roughly estimated to be 25.1kA/cm2, which is larger than required threshold current density of 1.4kA/cm2 calculated by combining analysis results of the scattering time, population inversion, gain of quantum cascade lasers, and coupling theory of a Bragg waveguide. The results strongly indicate the possibility of single-mode laser oscillation.

  • MolHF: Molecular Heterogeneous Attributes Fusion for Drug-Target Affinity Prediction on Heterogeneity

    Runze WANG  Zehua ZHANG  Yueqin ZHANG  Zhongyuan JIANG  Shilin SUN  Guixiang MA  

     
    PAPER-Smart Healthcare

      Pubricized:
    2022/05/31
      Vol:
    E106-D No:5
      Page(s):
    697-706

    Recent studies in protein structure prediction such as AlphaFold have enabled deep learning to achieve great attention on the Drug-Target Affinity (DTA) task. Most works are dedicated to embed single molecular property and homogeneous information, ignoring the diverse heterogeneous information gains that are contained in the molecules and interactions. Motivated by this, we propose an end-to-end deep learning framework to perform Molecular Heterogeneous features Fusion (MolHF) for DTA prediction on heterogeneity. To address the challenges that biochemical attributes locates in different heterogeneous spaces, we design a Molecular Heterogeneous Information Learning module with multi-strategy learning. Especially, Molecular Heterogeneous Attention Fusion module is present to obtain the gains of molecular heterogeneous features. With these, the diversity of molecular structure information for drugs can be extracted. Extensive experiments on two benchmark datasets show that our method outperforms the baselines in all four metrics. Ablation studies validate the effect of attentive fusion and multi-group of drug heterogeneous features. Visual presentations demonstrate the impact of protein embedding level and the model ability of fitting data. In summary, the diverse gains brought by heterogeneous information contribute to drug-target affinity prediction.

  • Bearing Remaining Useful Life Prediction Using 2D Attention Residual Network

    Wenrong XIAO  Yong CHEN  Suqin GUO  Kun CHEN  

     
    LETTER-Smart Industry

      Pubricized:
    2022/05/27
      Vol:
    E106-D No:5
      Page(s):
    818-820

    An attention residual network with triple feature as input is proposed to predict the remaining useful life (RUL) of bearings. First, the channel attention and spatial attention are connected in series into the residual connection of the residual neural network to obtain a new attention residual module, so that the newly constructed deep learning network can better pay attention to the weak changes of the bearing state. Secondly, the “triple feature” is used as the input of the attention residual network, so that the deep learning network can better grasp the change trend of bearing running state, and better realize the prediction of the RUL of bearing. Finally, The method is verified by a set of experimental data. The results show the method is simple and effective, has high prediction accuracy, and reduces manual intervention in RUL prediction.

  • Epileptic Seizure Prediction Using Convolutional Neural Networks and Fusion Features on Scalp EEG Signals

    Qixin LAN  Bin YAO  Tao QING  

     
    LETTER-Smart Healthcare

      Pubricized:
    2022/05/27
      Vol:
    E106-D No:5
      Page(s):
    821-823

    Epileptic seizure prediction is an important research topic in the clinical epilepsy treatment, which can provide opportunities to take precautionary measures for epilepsy patients and medical staff. EEG is an commonly used tool for studying brain activity, which records the electrical discharge of brain. Many studies based on machine learning algorithms have been proposed to solve the task using EEG signal. In this study, we propose a novel seizure prediction models based on convolutional neural networks and scalp EEG for a binary classification between preictal and interictal states. The short-time Fourier transform has been used to translate raw EEG signals into STFT sepctrums, which is applied as input of the models. The fusion features have been obtained through the side-output constructions and used to train and test our models. The test results show that our models can achieve comparable results in both sensitivity and FPR upon fusion features. The proposed patient-specific model can be used in seizure prediction system for EEG classification.

  • Effectiveness of Feature Extraction System for Multimodal Sensor Information Based on VRAE and Its Application to Object Recognition

    Kazuki HAYASHI  Daisuke TANAKA  

     
    LETTER-Object Recognition and Tracking

      Pubricized:
    2023/01/12
      Vol:
    E106-D No:5
      Page(s):
    833-835

    To achieve object recognition, it is necessary to find the unique features of the objects to be recognized. Results in prior research suggest that methods that use multiple modalities information are effective to find the unique features. In this paper, the overview of the system that can extract the features of the objects to be recognized by integrating visual, tactile, and auditory information as multimodal sensor information with VRAE is shown. Furthermore, a discussion about changing the combination of modalities information is also shown.

  • An Identifier Locator Separation Protocol for the Shared Prefix Model over IEEE WAVE IPv6 Networks Open Access

    Sangjin NAM  Sung-Gi MIN  

     
    PAPER-Network

      Pubricized:
    2022/10/21
      Vol:
    E106-B No:4
      Page(s):
    317-330

    As the active safety of vehicles has become essential, vehicular communication has been gaining attention. The IETF IPWAVE working group has proposed the shared prefix model-based vehicular link model. In the shared prefix model, a prefix is shared among RSUs to prevent changes in IPv6 addresses of a vehicle within a shared prefix domain. However, vehicle movement must be tracked to deliver packets to the serving RSU of the vehicle within a shared prefix domain. The Identifier/Locator Separation Protocol (ILSP) is one of the techniques used to handle vehicle movement. It has several drawbacks such as the inability to communicate with a standard IPv6 module without special components and the requirement to pass signaling messages between end hosts. Such drawbacks severely limit the service availability for a vehicle in the Internet. We propose an ILSP for a shared prefix model over IEEE WAVE IPv6 networks. The proposed protocol supports IPv6 communication between a standard IPv6 node in the Internet and a vehicle supporting the proposed protocol. In addition, the protocol hides vehicle movement within a shared prefix domain to peer hosts, eliminating the signaling between end hosts. The proposed protocol introduces a special NDP module based on IETF IPWAVE vehicular NDP to support vehicular mobility management within a shared prefix domain and minimize link-level multicast in WAVE networks.

  • A Beam Search Method with Adaptive Beam Width Control Based on Area Size for Initial Access

    Takuto ARAI  Daisei UCHIDA  Tatsuhiko IWAKUNI  Shuki WAI  Naoki KITA  

     
    PAPER-Wireless Communication Technologies

      Pubricized:
    2022/10/03
      Vol:
    E106-B No:4
      Page(s):
    359-366

    High gain antennas with narrow-beamforming are required to compensate for the high propagation loss expected in high frequency bands such as the millimeter wave and sub-terahertz wave bands, which are promising for achieving extremely high speeds and capacity. However using narrow-beamforming for initial access (IA) beam search in all directions incurs an excessive overhead. Using wide-beamforming can reduce the overhead for IA but it also shrinks the coverage area due to the lower beamforming gain. Here, it is assumed that there are some situations in which the required coverage distance differs depending on the direction from the antenna. For example, the distance to an floor for a ceiling-mounted antenna varies depending on the direction, and the distance to the obstruction becomes the required coverage distance for an antenna installation design that assumes line-of-sight. In this paper, we propose a novel IA beam search scheme with adaptive beam width control based on the distance to shield obstacles in each direction. Simulations and experiments show that the proposed method reduces the overhead by 20%-50% without shrinking the coverage area in shield environments compared to exhaustive beam search with narrow-beamforming.

  • An Interpretation Method on Amplitude Intensities for Response Waveforms of Backward Transient Scattered Field Components by a 2-D Coated Metal Cylinder

    Keiji GOTO  Toru KAWANO  

     
    PAPER

      Pubricized:
    2022/09/29
      Vol:
    E106-C No:4
      Page(s):
    118-126

    In this paper, we propose an interpretation method on amplitude intensities for response waveforms of backward transient scattered field components for both E- and H-polarizations by a 2-D coated metal cylinder. A time-domain (TD) asymptotic solution, which is referred to as a TD Fourier transform method (TD-FTM), is derived by applying the FTM to a backward transient scattered field expressed by an integral form. The TD-FTM is represented by a combination of a direct geometric optical ray (DGO) and a reflected GO (RGO) series. We use the TD-FTM to derive amplitude intensity ratios (AIRs) between adjacent backward transient scattered field components. By comparing the numerical values of the AIRs with those of the influence factors that compose the AIRs, major factor(s) can be identified, thereby allowing detailed interpretation method on the amplitude intensities for the response waveforms of backward transient scattered field components. The accuracy and practicality of the TD-FTM are evaluated by comparing it with three reference solutions. The effectiveness of an interpretation method on the amplitude intensities for response waveforms of backward transient scattered field components is revealed by identifying major factor(s) affecting the amplitude intensities.

  • An Efficient Combined Bit-Width Reducing Method for Ising Models

    Yuta YACHI  Masashi TAWADA  Nozomu TOGAWA  

     
    PAPER-Fundamentals of Information Systems

      Pubricized:
    2023/01/12
      Vol:
    E106-D No:4
      Page(s):
    495-508

    Annealing machines such as quantum annealing machines and semiconductor-based annealing machines have been attracting attention as an efficient computing alternative for solving combinatorial optimization problems. They solve original combinatorial optimization problems by transforming them into a data structure called an Ising model. At that time, the bit-widths of the coefficients of the Ising model have to be kept within the range that an annealing machine can deal with. However, by reducing the Ising-model bit-widths, its minimum energy state, or ground state, may become different from that of the original one, and hence the targeted combinatorial optimization problem cannot be well solved. This paper proposes an effective method for reducing Ising model's bit-widths. The proposed method is composed of two processes: First, given an Ising model with large coefficient bit-widths, the shift method is applied to reduce its bit-widths roughly. Second, the spin-adding method is applied to further reduce its bit-widths to those that annealing machines can deal with. Without adding too many extra spins, we efficiently reduce the coefficient bit-widths of the original Ising model. Furthermore, the ground state before and after reducing the coefficient bit-widths is not much changed in most of the practical cases. Experimental evaluations demonstrate the effectiveness of the proposed method, compared to existing methods.

  • Short Lattice Signature Scheme with Tighter Reduction under Ring-SIS Assumption

    Kaisei KAJITA  Go OHTAKE  Kazuto OGAWA  Koji NUIDA  Tsuyoshi TAKAGI  

     
    PAPER

      Pubricized:
    2022/09/08
      Vol:
    E106-A No:3
      Page(s):
    228-240

    We propose a short signature scheme under the ring-SIS assumption in the standard model. Specifically, by revisiting an existing construction [Ducas and Micciancio, CRYPTO 2014], we demonstrate lattice-based signatures with improved reduction loss. As far as we know, there are no ways to use multiple tags in the signature simulation of security proof in the lattice tag-based signatures. We address the tag-collision possibility in the lattice setting, which improves reduction loss. Our scheme generates tags from messages by constructing a scheme under a mild security condition that is existentially unforgeable against random message attack with auxiliary information. Thus our scheme can reduce the signature size since it does not need to send tags with the signatures. Our scheme has short signature sizes of O(1) and achieves tighter reduction loss than that of Ducas et al.'s scheme. Our proposed scheme has two variants. Our scheme with one property has tighter reduction and the same verification key size of O(log n) as that of Ducas et al.'s scheme, where n is the security parameter. Our scheme with the other property achieves much tighter reduction loss of O(Q/n) and verification key size of O(n), where Q is the number of signing queries.

  • Secure Revocation Features in eKYC - Privacy Protection in Central Bank Digital Currency

    Kazuo TAKARAGI  Takashi KUBOTA  Sven WOHLGEMUTH  Katsuyuki UMEZAWA  Hiroki KOYANAGI  

     
    PAPER

      Pubricized:
    2022/10/07
      Vol:
    E106-A No:3
      Page(s):
    325-332

    Central bank digital currencies require the implementation of eKYC to verify whether a trading customer is eligible online. When an organization issues an ID proof of a customer for eKYC, that proof is usually achieved in practice by a hierarchy of issuers. However, the customer wants to disclose only part of the issuer's chain and documents to the trading partner due to privacy concerns. In this research, delegatable anonymous credential (DAC) and zero-knowledge range proof (ZKRP) allow customers to arbitrarily change parts of the delegation chain and message body to range proofs expressed in inequalities. That way, customers can protect the privacy they need with their own control. Zero-knowledge proof is applied to prove the inequality between two time stamps by the time stamp server (signature presentation, public key revocation, or non-revocation) without disclosing the signature content and stamped time. It makes it possible to prove that the registration information of the national ID card is valid or invalid while keeping the user's personal information anonymous. This research aims to contribute to the realization of a sustainable financial system based on self-sovereign identity management with privacy-enhanced PKI.

  • Sub-Signal Channel Modulation for Hitless Redundancy Switching Systems

    Takahiro KUBO  Yuhei KAWAKAMI  Hironao ABE  Natsuki YASUHARA  Hideo KAWATA  Shinichi YOSHIHARA  Tomoaki YOSHIDA  

     
    PAPER-Network System

      Pubricized:
    2022/09/12
      Vol:
    E106-B No:3
      Page(s):
    221-229

    This paper proposes a sub-signal channel modulation scheme for hitless redundancy switching systems that offers highly confidential communications. A hitless redundancy switching system prevents frame loss by using multiple routes to forward the same frame. Although most studies on redundancy switching systems deal with frame duplication, elimination, and selection of redundant paths for the main signal, we focus on the transmission of the sub-signal channel. We introduce mathematical expressions to model the transmission rate and bit error rate of the sub-signal channel. To evaluate the validity of the models, we conduct numerical simulations to calculate the sub-signal transmission rate, main-signal transmission rate, and bit error rate of the sub-signal channel at physical transmission rates of 100Mb/s, 1Gb/s, and 10Gb/s. We discuss how to design sub-signal channel modulation on the basis of the evaluation results. We further discuss applications of sub-signal modulation in terms of network size and jitter.

  • Bending Loss Analysis of Chalcogenide Glass Channel Waveguides for Mid-Infrared Astrophotonic Devices Open Access

    Takashi YASUI  Jun-ichiro SUGISAKA  Koichi HIRAYAMA  

     
    BRIEF PAPER-Optoelectronics

      Pubricized:
    2022/08/25
      Vol:
    E106-C No:3
      Page(s):
    107-110

    In this study, the bending losses of chalcogenide glass channel optical waveguides consisting of an As2Se3 core and an As2S3 lower cladding layer were numerically evaluated across the astronomical N-band, which is the mid-infrared spectral range between the 8 µm and 12 µm wavelengths. The results reveal the design rules for bent waveguides in mid-infrared astrophotonic devices.

41-60hit(1933hit)