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621-640hit(16991hit)

  • Single-Image Camera Calibration for Furniture Layout Using Natural-Marker-Based Augmented Reality

    Kazumoto TANAKA  Yunchuan ZHANG  

     
    LETTER-Multimedia Pattern Processing

      Pubricized:
    2022/03/09
      Vol:
    E105-D No:6
      Page(s):
    1243-1248

    We propose an augmented-reality-based method for arranging furniture using natural markers extracted from the edges of the walls of rooms. The proposed method extracts natural markers and estimates the camera parameters from single images of rooms using deep neural networks. Experimental results show that in all the measurements, the superimposition error of the proposed method was lower than that of general marker-based methods that use practical-sized markers.

  • A 16-Bit Parallel Prefix Carry Look-Ahead Kogge-Stone Adder Implemented in Adiabatic Quantum-Flux-Parametron Logic

    Tomoyuki TANAKA  Christopher L. AYALA  Nobuyuki YOSHIKAWA  

     
    PAPER

      Pubricized:
    2022/01/19
      Vol:
    E105-C No:6
      Page(s):
    270-276

    Extremely energy-efficient logic devices are required for future low-power high-performance computing systems. Superconductor electronic technology has a number of energy-efficient logic families. Among them is the adiabatic quantum-flux-parametron (AQFP) logic family, which adiabatically switches the quantum-flux-parametron (QFP) circuit when it is excited by an AC power-clock. When compared to state-of-the-art CMOS technology, AQFP logic circuits have the advantage of relatively fast clock rates (5 GHz to 10 GHz) and 5 - 6 orders of magnitude reduction in energy before cooling overhead. We have been developing extremely energy-efficient computing processor components using the AQFP. The adder is the most basic computational unit and is important in the development of a processor. In this work, we designed and measured a 16-bit parallel prefix carry look-ahead Kogge-Stone adder (KSA). We fabricated the circuit using the AIST 10 kA/cm2 High-speed STandard Process (HSTP). Due to a malfunction in the measurement system, we were not able to confirm the complete operation of the circuit at the low frequency of 100 kHz in liquid He, but we confirmed that the outputs that we did observe are correct for two types of tests: (1) critical tests and (2) 110 random input tests in total. The operation margin of the circuit is wide, and we did not observe any calculation errors during measurement.

  • Gene Fingerprinting: Cracking Encrypted Tunnel with Zero-Shot Learning

    Ding LI  Chunxiang GU  Yuefei ZHU  

     
    PAPER-Information Network

      Pubricized:
    2022/03/23
      Vol:
    E105-D No:6
      Page(s):
    1172-1184

    Website Fingerprinting (WF) enables a passive attacker to identify which website a user is visiting over an encrypted tunnel. Current WF attacks have two strong assumptions: (i) specific tunnel, i.e., the attacker can train on traffic samples collected in a simulated tunnel with the same tunnel settings as the user, and (ii) pseudo-open-world, where the attacker has access to training samples of unmonitored sites and treats them as a separate class. These assumptions, while experimentally feasible, render WF attacks less usable in practice. In this paper, we present Gene Fingerprinting (GF), a new WF attack that achieves cross-tunnel transferability by generating fingerprints that reflect the intrinsic profile of a website. The attack leverages Zero-shot Learning — a machine learning technique not requiring training samples to identify a given class — to reduce the effort to collect data from different tunnels and achieve a real open-world. We demonstrate the attack performance using three popular tunneling tools: OpenSSH, Shadowsocks, and OpenVPN. The GF attack attains over 94% accuracy on each tunnel, far better than existing CUMUL, DF, and DDTW attacks. In the more realistic open-world scenario, the attack still obtains 88% TPR and 9% FPR, outperforming the state-of-the-art attacks. These results highlight the danger of our attack in various scenarios where gathering and training on a tunnel-specific dataset would be impractical.

  • Improvement of Radiation Efficiency for Platform-Mounted Small Antenna by Evaluation of Characteristic Mode with Metal Casing Using Infinitesimal Dipole

    Takumi NISHIME  Hiroshi HASHIGUCHI  Naobumi MICHISHITA  Hisashi MORISHITA  

     
    PAPER-Antennas

      Pubricized:
    2021/12/14
      Vol:
    E105-B No:6
      Page(s):
    722-728

    Platform-mounted small antennas increase dielectric loss and conductive loss and decrease the radiation efficiency. This paper proposes a novel antenna design method to improve radiation efficiency for platform-mounted small antennas by characteristic mode analysis. The proposed method uses mapping of modal weighting coefficient (MWC) and infinitesimal dipole and evaluate the metal casing with 100mm × 55mm × 23mm as a platform excited by an inverted-F antenna. The simulation and measurement results show that the radiation efficiency of 5% is improved with the whole system from 2.5% of the single antenna.

  • Toward Realization of Scalable Packaging and Wiring for Large-Scale Superconducting Quantum Computers Open Access

    Shuhei TAMATE  Yutaka TABUCHI  Yasunobu NAKAMURA  

     
    INVITED PAPER

      Pubricized:
    2021/12/03
      Vol:
    E105-C No:6
      Page(s):
    290-295

    In this paper, we review the basic components of superconducting quantum computers. We mainly focus on the packaging and wiring technologies required to realize large-scalable superconducting quantum computers.

  • A Metadata Prefetching Mechanism for Hybrid Memory Architectures Open Access

    Shunsuke TSUKADA  Hikaru TAKAYASHIKI  Masayuki SATO  Kazuhiko KOMATSU  Hiroaki KOBAYASHI  

     
    PAPER

      Pubricized:
    2021/12/03
      Vol:
    E105-C No:6
      Page(s):
    232-243

    A hybrid memory architecture (HMA) that consists of some distinct memory devices is expected to achieve a good balance between high performance and large capacity. Unlike conventional memory architectures, the HMA needs the metadata for data management since the data are migrated between the memory devices during the execution of an application. The memory controller caches the metadata to avoid accessing the memory devices for the metadata reference. However, as the amount of the metadata increases in proportion to the size of the HMA, the memory controller needs to handle a large amount of metadata. As a result, the memory controller cannot cache all the metadata and increases the number of metadata references. This results in an increase in the access latency to reach the target data and degrades the performance. To solve this problem, this paper proposes a metadata prefetching mechanism for HMAs. The proposed mechanism loads the metadata needed in the near future by prefetching. Moreover, to increase the effect of the metadata prefetching, the proposed mechanism predicts the metadata used in the near future based on an address difference that is the difference between two consecutive access addresses. The evaluation results show that the proposed metadata prefetching mechanism can improve the instructions per cycle by up to 44% and 9% on average.

  • Cluster Expansion Method for Critical Node Problem Based on Contraction Mechanism in Sparse Graphs

    Zheng WANG  Yi DI  

     
    PAPER-Fundamentals of Information Systems

      Pubricized:
    2022/02/24
      Vol:
    E105-D No:6
      Page(s):
    1135-1149

    The objective of critical nodes problem is to minimize pair-wise connectivity as a result of removing a specific number of nodes in the residual graph. From a mathematical modeling perspective, it comes the truth that the more the number of fragmented components and the evenly distributed of disconnected sub-graphs, the better the quality of the solution. Basing on this conclusion, we proposed a new Cluster Expansion Method for Critical Node Problem (CEMCNP), which on the one hand exploits a contraction mechanism to greedy simplify the complexity of sparse graph model, and on the other hand adopts an incremental cluster expansion approach in order to maintain the size of formed component within reasonable limitation. The proposed algorithm also relies heavily on the idea of multi-start iterative local search algorithm, whereas brings in a diversified late acceptance local search strategy to keep the balance between interleaving diversification and intensification in the process of neighborhood search. Extensive evaluations show that CEMCNP running on 35 of total 42 benchmark instances are superior to the outcome of KBV, while holding 3 previous best results out of the challenging instances. In addition, CEMCNP also demonstrates equivalent performance in comparison with the existing MANCNP and VPMS algorithms over 22 of total 42 graph models with fewer number of node exchange operations.

  • Supervised Audio Source Separation Based on Nonnegative Matrix Factorization with Cosine Similarity Penalty Open Access

    Yuta IWASE  Daichi KITAMURA  

     
    PAPER-Engineering Acoustics

      Pubricized:
    2021/12/08
      Vol:
    E105-A No:6
      Page(s):
    906-913

    In this study, we aim to improve the performance of audio source separation for monaural mixture signals. For monaural audio source separation, semisupervised nonnegative matrix factorization (SNMF) can achieve higher separation performance by employing small supervised signals. In particular, penalized SNMF (PSNMF) with orthogonality penalty is an effective method. PSNMF forces two basis matrices for target and nontarget sources to be orthogonal to each other and improves the separation accuracy. However, the conventional orthogonality penalty is based on an inner product and does not affect the estimation of the basis matrix properly because of the scale indeterminacy between the basis and activation matrices in NMF. To cope with this problem, a new PSNMF with cosine similarity between the basis matrices is proposed. The experimental comparison shows the efficacy of the proposed cosine similarity penalty in supervised audio source separation.

  • Software Implementation of Optimal Pairings on Elliptic Curves with Odd Prime Embedding Degrees

    Yu DAI  Zijian ZHOU  Fangguo ZHANG  Chang-An ZHAO  

     
    PAPER-Cryptography and Information Security

      Pubricized:
    2021/11/26
      Vol:
    E105-A No:5
      Page(s):
    858-870

    Pairing computations on elliptic curves with odd prime degrees are rarely studied as low efficiency. Recently, Clarisse, Duquesne and Sanders proposed two new curves with odd prime embedding degrees: BW13-P310 and BW19-P286, which are suitable for some special cryptographic schemes. In this paper, we propose efficient methods to compute the optimal ate pairing on this types of curves, instantiated by the BW13-P310 curve. We first extend the technique of lazy reduction into the finite field arithmetic. Then, we present a new method to execute Miller's algorithm. Compared with the standard Miller iteration formulas, the new ones provide a more efficient software implementation of pairing computations. At last, we also give a fast formula to perform the final exponentiation. Our implementation results indicate that it can be computed efficiently, while it is slower than that over the (BLS12-P446) curve at the same security level.

  • Exact Algorithm to Solve Continuous Similarity Search for Evolving Queries and Its Variant

    Tomohiro YAMAZAKI  Hisashi KOGA  

     
    PAPER

      Pubricized:
    2022/02/07
      Vol:
    E105-D No:5
      Page(s):
    898-908

    We study the continuous similarity search problem for evolving queries which has recently been formulated. Given a data stream and a database composed of n sets of items, the purpose of this problem is to maintain the top-k most similar sets to the query which evolves over time and consists of the latest W items in the data stream. For this problem, the previous exact algorithm adopts a pruning strategy which, at the present time T, decides the candidates of the top-k most similar sets from past similarity values and computes the similarity values only for them. This paper proposes a new exact algorithm which shortens the execution time by computing the similarity values only for sets whose similarity values at T can change from time T-1. We identify such sets very fast with frequency-based inverted lists (FIL). Moreover, we derive the similarity values at T in O(1) time by updating the previous values computed at time T-1. Experimentally, our exact algorithm runs faster than the previous exact algorithm by one order of magnitude and as fast as the previous approximation algorithm.

  • Resilient Virtual Network Embedding Ensuring Connectivity under Substrate Node Failures

    Nagao OGINO  

     
    PAPER-Network

      Pubricized:
    2021/11/11
      Vol:
    E105-B No:5
      Page(s):
    557-568

    A variety of smart services are being provided on multiple virtual networks embedded into a common inter-cloud substrate network. The substrate network operator deploys critical substrate nodes so that multiple service providers can achieve enhanced services due to the secure sharing of their service data. Even if one of the critical substrate nodes incurs damage, resiliency of the enhanced services can be assured due to reallocation of the workload and periodic backup of the service data to the other normal critical substrate nodes. However, the connectivity of the embedded virtual networks must be maintained so that the enhanced services can be continuously provided to all clients on the virtual networks. This paper considers resilient virtual network embedding (VNE) that ensures the connectivity of the embedded virtual networks after critical substrate node failures have occurred. The resilient VNE problem is formulated using an integer linear programming model and a distance-based method is proposed to solve the large-scale resilient VNE problem efficiently. Simulation results demonstrate that the distance-based method can derive a sub-optimum VNE solution with a small computational effort. The method derived a VNE solution with an approximation ratio of less than 1.2 within ten seconds in all the simulation experiments.

  • Analysis and Design of a Linear Ka-Band Power Amplifier in 65-nm CMOS for 5G Applications

    Chongyu YU  Jun FENG  

     
    PAPER-Microwaves, Millimeter-Waves

      Pubricized:
    2021/12/14
      Vol:
    E105-C No:5
      Page(s):
    184-193

    A linear and broadband power amplifier (PA) for 5G phased-array is presented. The design improves the linearity by operating the transistors in deep class AB region. The design broadens the bandwidth by applying the inter-stage weakly-coupled transformer. The theory of transformers is illustrated by analyzing the odd- and even-mode model. Based on this, the odd-mode Q factor is used to evaluate the quality of impedance matching. Weakly- and strongly-coupled transformers are compared and analyzed in both the design process and applicable characteristics. Besides, a well-founded method to achieve the transformer-based balanced-unbalanced transformation is proposed. The fully integrated two-stage PA is designed and implemented in a 65-nm CMOS process with a 1-V power supply to provide a maximum small-signal gain of 19dB. The maximum output 1-dB compressed power (P1dB) of 17.4dBm and the saturated output power (PSAT) of 18dBm are measured at 28GHz. The power-added efficiency (PAE) of the P1dB is 26.5%. From 23 to 32GHz, the measured P1dB is above 16dBm, covering the potential 5G bands worldwide around 28GHz.

  • Predicting A Growing Stage of Rice Plants Based on The Cropping Records over 25 Years — A Trial of Feature Engineering Incorporating Hidden Regional Characteristics —

    Hiroshi UEHARA  Yasuhiro IUCHI  Yusuke FUKAZAWA  Yoshihiro KANETA  

     
    PAPER

      Pubricized:
    2021/12/29
      Vol:
    E105-D No:5
      Page(s):
    955-963

    This study tries to predict date of ear emergence of rice plants, based on cropping records over 25 years. Predicting ear emergence of rice plants is known to be crucial for practicing good harvesting quality, and has long been dependent upon old farmers who acquire skills of intuitive prediction based on their long term experiences. Facing with aging farmers, data driven approach for the prediction have been pursued. Nevertheless, they are not necessarily sufficient in terms of practical use. One of the issue is to adopt weather forecast as the feature so that the predictive performance is varied by the accuracy of the forecast. The other issue is that the performance is varied by region and the regional characteristics have not been used as the features for the prediction. With this background, we propose a feature engineering to quantify hidden regional characteristics as the feature for the prediction. Further the feature is engineered based only on observational data without any forecast. Applying our proposal to the data on the cropping records resulted in sufficient predictive performance, ±2.69days of RMSE.

  • Implementation of a Multi-Word Compare-and-Swap Operation without Garbage Collection

    Kento SUGIURA  Yoshiharu ISHIKAWA  

     
    PAPER

      Pubricized:
    2022/02/03
      Vol:
    E105-D No:5
      Page(s):
    946-954

    With the rapid increase in the number of CPU cores, software that can utilize these many cores is required. A lock-free algorithm based on compare-and-swap (CAS) operations is one of the concurrency control methods to implement such multi-threading software. A multi-word CAS (MwCAS) operation is an extension of a CAS operation to swap multiple words atomically. However, we noticed that the performance of the existing MwCAS implementation is limited because of garbage collection even if in a low-contention environment. To achieve high performance in low-contention workloads, we propose a new MwCAS algorithm without garbage collection. Experimental results show that our approach is three to five times faster than implementation with garbage collection in low-contention workloads. Moreover, the performance of the proposed method is also superior in a high-contention environment.

  • Performance Analysis on the Uplink of Massive MIMO Systems with Superimposed Pilots and Arbitrary-Bit ADCs

    Chen CHEN  Wence ZHANG  Xu BAO  Jing XIA  

     
    PAPER-Wireless Communication Technologies

      Pubricized:
    2021/10/28
      Vol:
    E105-B No:5
      Page(s):
    629-637

    This paper studies the performance of quantized massive multiple-input multiple-output (MIMO) systems with superimposed pilots (SP), using linear minimum mean-square-error (LMMSE) channel estimation and maximum ratio combining (MRC) detection. In contrast to previous works, arbitrary-bit analog-to-digital converters (ADCs) are considered. We derive an accurate approximation of the uplink achievable rate considering the removal of estimated pilots. Based on the analytical expression, the optimal pilot power factor that maximizes the achievable rate is deduced and an expression for energy efficiency (EE) is given. In addition, the achievable rate and the optimal power allocation policy under some asymptotic limits are analyzed. Analysis shows that the systems with higher-resolution ADCs or larger number of base station (BS) antennas need to allocate more power to pilots. In contrast, more power needs to be allocated to data when the channel is slowly varying. Numerical results show that in the low signal-to-noise ratio (SNR) region, for 1-bit quantizers, SP outperforms time-multiplexed pilots (TP) in most cases, while for systems with higher-resolution ADCs, the SP scheme is suitable for the scenarios with comparatively small number of BS antennas and relatively long channel coherence time.

  • Research on the Algorithm of License Plate Recognition Based on MPGAN Haze Weather

    Weiguo ZHANG  Jiaqi LU  Jing ZHANG  Xuewen LI  Qi ZHAO  

     
    PAPER-Image Recognition, Computer Vision

      Pubricized:
    2022/02/21
      Vol:
    E105-D No:5
      Page(s):
    1085-1093

    The haze situation will seriously affect the quality of license plate recognition and reduce the performance of the visual processing algorithm. In order to improve the quality of haze pictures, a license plate recognition algorithm based on haze weather is proposed in this paper. The algorithm in this paper mainly consists of two parts: The first part is MPGAN image dehazing, which uses a generative adversarial network to dehaze the image, and combines multi-scale convolution and perceptual loss. Multi-scale convolution is conducive to better feature extraction. The perceptual loss makes up for the shortcoming that the mean square error (MSE) is greatly affected by outliers; the second part is to recognize the license plate, first we use YOLOv3 to locate the license plate, the STN network corrects the license plate, and finally enters the improved LPRNet network to get license plate information. Experimental results show that the dehazing model proposed in this paper achieves good results, and the evaluation indicators PSNR and SSIM are better than other representative algorithms. After comparing the license plate recognition algorithm with the LPRNet algorithm, the average accuracy rate can reach 93.9%.

  • Neuron-Network-Based Mixture Probability Model for Passenger Walking Time Distribution Estimation

    Hao FANG  Chi-Hua CHEN  Dewang CHEN  Feng-Jang HWANG  

     
    LETTER-Artificial Intelligence, Data Mining

      Pubricized:
    2022/01/28
      Vol:
    E105-D No:5
      Page(s):
    1112-1115

    Aiming for accurate data-driven predictions for the passenger walking time, this study proposes a novel neuron-network-based mixture probability (NNBMP) model with repetition learning (RL) to estimate the probability density distribution of passenger walking time (PWT) in the metro station. Our conducted experiments for Fuzhou metro stations demonstrate that the proposed NNBMP-RL model achieved the mean absolute error, mean square error, and mean absolute percentage error of 0.0078, 1.33 × 10-4, and 19.41%, respectively, and it outperformed all the seven compared models. The developed NNBMP model fitting accurately the PWT distribution in the metro station is readily applicable to the microscopic analyses of passenger flow.

  • Pairwise Similarity Normalization Based on a Hubness Score for Improving Cover Song Retrieval Accuracy

    Jin S. SEO  

     
    LETTER-Music Information Processing

      Pubricized:
    2022/02/21
      Vol:
    E105-D No:5
      Page(s):
    1130-1134

    A hubness-score based normalization of the pairwise similarity is proposed for the sequence-alignment based cover song retrieval. The hubness, which is the tendency of some data points in high-dimensional data sets to link more frequently to other points than the rest of the points from the set, is widely-known to deteriorate the information retrieval accuracy. This paper tries to relieve the performance degradation due to the hubness by normalizing the pairwise similarity with a hubness score. Experiments on two cover song datasets confirm that the proposed similarity normalization improves the cover song retrieval accuracy.

  • Deep Coalitional Q-Learning for Dynamic Coalition Formation in Edge Computing

    Shiyao DING  Donghui LIN  

     
    PAPER

      Pubricized:
    2021/12/14
      Vol:
    E105-D No:5
      Page(s):
    864-872

    With the high development of computation requirements in Internet of Things, resource-limited edge servers usually require to cooperate to perform the tasks. Most related studies usually assume a static cooperation approach which might not suit the dynamic environment of edge computing. In this paper, we consider a dynamic cooperation approach by guiding edge servers to form coalitions dynamically. It raises two issues: 1) how to guide them to optimally form coalitions and 2) how to cope with the dynamic feature where server statuses dynamically change as the tasks are performed. The coalitional Markov decision process (CMDP) model proposed in our previous work can handle these issues well. However, its basic solution, coalitional Q-learning, cannot handle the large scale problem when the task number is large in edge computing. Our response is to propose a novel algorithm called deep coalitional Q-learning (DCQL) to solve it. To sum up, we first formulate the dynamic cooperation problem of edge servers as a CMDP: each edge server is regarded as an agent and the dynamic process is modeled as a MDP where the agents observe the current state to formulate several coalitions. Each coalition takes an action to impact the environment which correspondingly transfers to the next state to repeat the above process. Then, we propose DCQL which includes a deep neural network and so can well cope with large scale problem. DCQL can guide the edge servers to form coalitions dynamically with the target of optimizing some goal. Furthermore, we run experiments to verify our proposed algorithm's effectiveness in different settings.

  • Bit-Parallel Systolic Architecture for AB and AB2 Multiplications over GF(2m)

    Kee-Won KIM  

     
    BRIEF PAPER-Electronic Circuits

      Pubricized:
    2021/11/02
      Vol:
    E105-C No:5
      Page(s):
    203-206

    In this paper, we present a scheme to compute either AB or AB2 multiplications over GF(2m) and propose a bit-parallel systolic architecture based on the proposed algorithm. The AB multiplication algorithm is derived in the same form as the formula of AB2 multiplication algorithm, and an architecture that can perform AB multiplication by adding very little extra hardware to AB2 multiplier is designed. Therefore, the proposed architecture can be effectively applied to hardware constrained applications that cannot deploy AB2 multiplier and AB multiplier separately.

621-640hit(16991hit)