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121-140hit(3318hit)

  • PDAA3C: An A3C-Based Multi-Path Data Scheduling Algorithm

    Teng LIANG  Ao ZHAN  Chengyu WU  Zhengqiang WANG  

     
    LETTER-Fundamentals of Information Systems

      Pubricized:
    2022/09/13
      Vol:
    E105-D No:12
      Page(s):
    2127-2130

    In this letter, a path dynamics assessment asynchronous advantage actor-critic scheduling algorithm (PDAA3C) is proposed to solve the MPTCP scheduling problem by using deep reinforcement learning Actor-Critic framework. The algorithm picks out the optimal transmitting path faster by multi-core asynchronous updating and also guarantee the network fairness. Compared with the existing algorithms, the proposed algorithm achieves 8.6% throughput gain over RLDS algorithm, and approaches the theoretic upper bound in the NS3 simulation.

  • Holmes: A Hardware-Oriented Optimizer Using Logarithms

    Yoshiharu YAMAGISHI  Tatsuya KANEKO  Megumi AKAI-KASAYA  Tetsuya ASAI  

     
    PAPER

      Pubricized:
    2022/05/11
      Vol:
    E105-D No:12
      Page(s):
    2040-2047

    Edge computing, which has been gaining attention in recent years, has many advantages, such as reducing the load on the cloud, not being affected by the communication environment, and providing excellent security. Therefore, many researchers have attempted to implement neural networks, which are representative of machine learning in edge computing. Neural networks can be divided into inference and learning parts; however, there has been little research on implementing the learning component in edge computing in contrast to the inference part. This is because learning requires more memory and computation than inference, easily exceeding the limit of resources available for edge computing. To overcome this problem, this research focuses on the optimizer, which is the heart of learning. In this paper, we introduce our new optimizer, hardware-oriented logarithmic momentum estimation (Holmes), which incorporates new perspectives not found in existing optimizers in terms of characteristics and strengths of hardware. The performance of Holmes was evaluated by comparing it with other optimizers with respect to learning progress and convergence speed. Important aspects of hardware implementation, such as memory and operation requirements are also discussed. The results show that Holmes is a good match for edge computing with relatively low resource requirements and fast learning convergence. Holmes will help create an era in which advanced machine learning can be realized on edge computing.

  • A 16/32Gbps Dual-Mode SerDes Transmitter with Linearity Enhanced SST Driver

    Li DING  Jing JIN  Jianjun ZHOU  

     
    PAPER

      Pubricized:
    2022/05/13
      Vol:
    E105-A No:11
      Page(s):
    1443-1449

    This brief presents A 16/32Gb/s dual-mode transmitter including a linearity calibration loop to maintain amplitude linearity of the SST driver. Linearity detection and corresponding master-slave power supply circuits are designed to implement the proposed architecture. The proposed transmitter is manufactured in a 22nm FD-SOI process. The linearity calibration loop reduces the peak INL errors of the transmitter by 50%, and the RLM rises from 92.4% to 98.5% when the transmitter is in PAM4 mode. The chip area of the transmitter is 0.067mm2, while the proposed linearity enhanced part is 0.05×0.02mm2 and the total power consumption is 64.6mW with a 1.1V power supply. The linearity calibration loop can be detached from the circuit without consuming extra power.

  • Edge Computing-Enhanced Network Redundancy Elimination for Connected Cars

    Masahiro YOSHIDA  Koya MORI  Tomohiro INOUE  Hiroyuki TANAKA  

     
    PAPER

      Pubricized:
    2022/05/27
      Vol:
    E105-B No:11
      Page(s):
    1372-1379

    Connected cars generate a huge amount of Internet of Things (IoT) sensor information called Controller Area Network (CAN) data. Recently, there is growing interest in collecting CAN data from connected cars in a cloud system to enable life-critical use cases such as safe driving support. Although each CAN data packet is very small, a connected car generates thousands of CAN data packets per second. Therefore, real-time CAN data collection from connected cars in a cloud system is one of the most challenging problems in the current IoT. In this paper, we propose an Edge computing-enhanced network Redundancy Elimination service (EdgeRE) for CAN data collection. In developing EdgeRE, we designed a CAN data compression architecture that combines in-vehicle computers, edge datacenters and a public cloud system. EdgeRE includes the idea of hierarchical data compression and dynamic data buffering at edge datacenters for real-time CAN data collection. Across a wide range of field tests with connected cars and an edge computing testbed, we show that the EdgeRE reduces bandwidth usage by 88% and the number of packets by 99%.

  • Incentive-Stable Matching Protocol for Service Chain Placement in Multi-Operator Edge System

    Jen-Yu WANG  Li-Hsing YEN  Juliana LIMAN  

     
    PAPER

      Pubricized:
    2022/05/27
      Vol:
    E105-B No:11
      Page(s):
    1353-1360

    Network Function Virtualization (NFV) enables the embedding of Virtualized Network Function (VNF) into commodity servers. A sequence of VNFs can be chained in a particular order to form a service chain (SC). This paper considers placing multiple SCs in a geo-distributed edge system owned by multiple service providers (SPs). For a pair of SC and SP, minimizing the placement cost while meeting a latency constraint is formulated as an integer programming problem. As SC clients and SPs are self-interested, we study the matching between SCs and SPs that respects individual's interests yet maximizes social welfare. The proposed matching approach excludes any blocking individual and block pair which may jeopardize the stability of the result. Simulation results show that the proposed approach performs well in terms of social welfare but is suboptimal concerning the number of placed SCs.

  • Design of a Compact Triple-Mode Dielectric Resonator BPF with Wide Spurious-Free Performance Open Access

    Fan LIU  Zhewang MA  Weihao ZHANG  Masataka OHIRA  Dongchun QIAO  Guosheng PU  Masaru ICHIKAWA  

     
    PAPER

      Pubricized:
    2022/03/30
      Vol:
    E105-C No:11
      Page(s):
    660-666

    A novel compact 5-pole bandpass filter (BPF) using two different types of resonators, one is coaxial TEM-mode resonator and the other dielectric triple-mode resonator, is proposed in this paper. The coaxial resonator is a simple single-mode resonator, while the triple-mode dielectric resonator (DR) includes one TM01δ mode and two degenerate HE11 modes. An excellent spurious performance of the BPF is obtained due to the different resonant behaviors of these two types of resonators used in the BPF. The coupling scheme of the 5-pole BPF includes two cascade triplets (CTs) which produce two transmission zeros (TZs) and a sharp skirt of the passband. Behaviors of the resonances, the inter-resonance couplings, as well as their tuning methods are investigated in detail. A procedure of mapping the coupling matrix of the BPF to its physical dimensions is developed, and an optimization of these physical dimensions is implemented to achieve best performance of the filter. The designed BPF is operated at 1.84GHz with a bandwidth of 51MHz. The stopband rejection is better than 20dB up to 9.7GHz (about 5.39×f0) except 7.85GHz. Good agreement between the designed and theoretically synthesized responses of the BPF is reached, verifying well the proposed configuration of the BPF and its design method.

  • Workload-Driven Analysis on the Performance Characteristics of GPU-Accelerated DBMSes

    Junyoung AN  Young-Kyoon SUH  Byungchul TAK  

     
    LETTER-Data Engineering, Web Information Systems

      Vol:
    E105-D No:11
      Page(s):
    1984-1989

    This letter conducts an in-depth empirical analysis of the influence of various query characteristics on the performance of modern GPU DBMSes. Our analysis reveals that, although they can efficiently process concurrent queries, the GPU DBMSes we consider still should address various performance concerns including n-way joins, aggregates, and selective scans.

  • Research on Stability of MMC-Based Medium Voltage DC Bus on Ships Based on Lyapunov Method Open Access

    Liang FANG  Xiaoyan XU  Tomasz TARASIUK  

     
    PAPER

      Pubricized:
    2022/05/09
      Vol:
    E105-C No:11
      Page(s):
    675-683

    Modular multilevel converters (MMCs) are an emerging and promising option for medium voltage direct current (MVDC) of all- electric ships. In order to improve the stability of the MVDC transmission system for ships, this paper presents a new control inputs-based Lyapunov strategy based on feedback linearization. Firstly, a set of dynamics equations is proposed based on separating the dynamics of AC-part currents and MMCs circulating currents. The new control inputs can be obtained by the use of feedback linearization theory applied to the dynamic equations. To complete the dynamic parts of the new control inputs from the viewpoint of MVDC system stability, the Lyapunov theory is designed some compensators to demonstrate the effects of the new control inputs on the MMCs state variable errors and its dynamic. In addition, the carrier phase shifted modulation strategy is used because of applying the few number of converter modules to the MVDC system for ships. Moreover, relying on the proposed control strategy, a simulation model is built in MATLAB/SIMULINK software, where simulation results are utilized to verify the validity of proposed control strategy in the MMC-based MVDC system for ships.

  • Performance and Security Evaluation of Table-Based Access Control Applied to IoT Data Distribution Method Open Access

    Masaki YOSHII  Ryohei BANNO  Osamu MIZUNO  

     
    PAPER

      Pubricized:
    2022/05/27
      Vol:
    E105-B No:11
      Page(s):
    1390-1399

    New services can use fog nodes to distribute Internet of Things (IoT) data. To distribute IoT data, we apply the publish/subscribe messaging model to a fog computing system. A service provider assigns a unique identifier, called a Tag ID, to a player who owes data. A Tag ID matches multiple IDs and resolves the naming rule for data acquisition. However, when users configure their fog node and distribute IoT data to multiple players, the distributed data may contain private information. We propose a table-based access control list (ACL) to manage data transmission permissions to address this issue. It is possible to avoid unnecessary transmission of private data by using a table-based ACL. Furthermore, because there are fewer data transmissions, table-based ACL reduces traffic. Consequently, the overall system's average processing delay time can be reduced. The proposed method's performance was confirmed by simulation results. Table-based ACL, particularly, could reduce processing delay time by approximately 25% under certain conditions. We also concentrated on system security. The proposed method was used, and a qualitative evaluation was performed to demonstrate that security is guaranteed.

  • Multi-Target Position and Velocity Estimation Algorithm Based on Time Delay and Doppler Shift in Passive MIMO Radar

    Yao ZHOU  Hairui YU  Wenjie XU  Siyi YAO  Li WANG  Hongshu LIAO  Wanchun LI  

     
    PAPER-Digital Signal Processing

      Pubricized:
    2022/05/18
      Vol:
    E105-A No:11
      Page(s):
    1466-1477

    In this paper, a passive multiple-input multiple-output (MIMO) radar system with widely separated antennas that estimates the positions and velocities of multiple moving targets by utilizing time delay (TD) and doppler shift (DS) measurements is proposed. Passive radar systems can detect targets by using multiple uncoordinated and un-synchronized illuminators and we assume that all the measurements including TD and DS have been known by a preprocessing method. In this study, the algorithm can be divided into three stages. First, based on location information within a certain range and utilizing the DBSCAN cluster algorithm we can obtain the initial position of each target. In the second stage according to the correlation between the TD measurements of each target in a specific receiver and the DSs, we can find the set of DS measurements for each target. Therefore, the initial speed estimated values can be obtained employing the least squares (LS) method. Finally, maximum likelihood (ML) estimation of a first-order Taylor expansion joint TD and DS is applied for a better solution. Extensive simulations show that the proposed algorithm has a good estimation performance and can achieve the Cramér-Rao lower bound (CRLB) under the condition of moderate measurement errors.

  • Spy in Your Eye: Spycam Attack via Open-Sided Mobile VR Device

    Jiyeon LEE  Kilho LEE  

     
    LETTER-Human-computer Interaction

      Pubricized:
    2022/07/22
      Vol:
    E105-D No:10
      Page(s):
    1817-1820

    Privacy violations via spy cameras are becoming increasingly serious. With the recent advent of various smart home IoT devices, such as smart TVs and robot vacuum cleaners, spycam attacks that steal users' information are being carried out in more unpredictable ways. In this paper, we introduce a new spycam attack on a mobile WebVR environment. It is performed by a web attacker who maliciously accesses the back-facing cameras of victims' mobile devices while they are browsing the attacker's WebVR site. This has the power to allow the attacker to capture victims' surroundings even at the desired field of view through sophisticated content placement in VR scenes, resulting in serious privacy breaches for mobile VR users. In this letter, we introduce a new threat facing mobile VR and show that it practically works with major browsers in a stealthy manner.

  • MFSFET with 5nm Thick Ferroelectric Nondoped HfO2 Gate Insulator Utilizing Low Power Sputtering for Pt Gate Electrode Deposition

    Joong-Won SHIN  Masakazu TANUMA  Shun-ichiro OHMI  

     
    PAPER

      Pubricized:
    2022/06/27
      Vol:
    E105-C No:10
      Page(s):
    578-583

    In this research, we investigated the metal-ferroelectric-semiconductor field-effect transistors (MFSFETs) with 5nm thick nondoped HfO2 gate insulator by decreasing the sputtering power for Pt gate electrode deposition. The leakage current was effectively reduced to 2.6×10-8A/cm2 at the voltage of -1.5V by the sputtering power of 40W for Pt electrode deposition. Furthermore, the memory window (MW) of 0.53V and retention time over 10 years were realized.

  • Low-Complexity Hybrid Precoding Based on PAST for Millimeter Wave Massive MIMO System Open Access

    Rui JIANG  Xiao ZHOU  You Yun XU  Li ZHANG  

     
    PAPER-Fundamental Theories for Communications

      Pubricized:
    2022/04/21
      Vol:
    E105-B No:10
      Page(s):
    1192-1201

    Millimeter wave (mmWave) massive Multiple-Input Multiple-Output (MIMO) systems generally adopt hybrid precoding combining digital and analog precoder as an alternative to full digital precoding to reduce RF chains and energy consumption. In order to balance the relationship between spectral efficiency, energy efficiency and hardware complexity, the hybrid-connected system structure should be adopted, and then the solution process of hybrid precoding can be simplified by decomposing the total achievable rate into several sub-rates. However, the singular value decomposition (SVD) incurs high complexity in calculating the optimal unconstrained hybrid precoder for each sub-rate. Therefore, this paper proposes PAST, a low complexity hybrid precoding algorithm based on projection approximate subspace tracking. The optimal unconstrained hybrid precoder of each sub-rate is estimated with the PAST algorithm, which avoids the high complexity process of calculating the left and right singular vectors and singular value matrix by SVD. Simulations demonstrate that PAST matches the spectral efficiency of SVD-based hybrid precoding in full-connected (FC), hybrid-connected (HC) and sub-connected (SC) system structure. Moreover, the superiority of PAST over SVD-based hybrid precoding in terms of complexity and increases with the number of transmitting antennas.

  • The Effect of Inter Layers on the Ferroelectric Undoped HfO2 Formation

    Masakazu TANUMA  Joong-Won SHIN  Shun-ichiro OHMI  

     
    PAPER

      Pubricized:
    2022/06/27
      Vol:
    E105-C No:10
      Page(s):
    584-588

    In this research, we investigated the effect of Hf inter layer and chemical oxide on Si(100) substrate on the ferroelectric undoped HfO2 deposition. In case with 1 nm-thick Hf inter layer, equivalent oxide thickness (EOT) was decreased from 6.0 to 4.8 nm for 10 nm-thick HfO2 with decreasing annealing temperature. In case with 0.5 nm-thick chemical oxide, EOT was decreased from 3.9 to 3.6 nm in MFS diodes for 5 nm-thick HfO2. The MFSFET was fabricated with 10 nm-thick HfO2 utilizing Hf inter layer. The subthreshold swing was improved from 240 mV/dec. to 120 mV/dec. and saturation mobility was increased from 70 cm2/(Vs) to 140 cm2/(Vs) by inserting Hf inter layer.

  • A Bus Crowdedness Sensing System Using Deep-Learning Based Object Detection

    Wenhao HUANG  Akira TSUGE  Yin CHEN  Tadashi OKOSHI  Jin NAKAZAWA  

     
    PAPER

      Pubricized:
    2022/06/23
      Vol:
    E105-D No:10
      Page(s):
    1712-1720

    Crowdedness of buses is playing an increasingly important role in the disease control of COVID-19. The lack of a practical approach to sensing the crowdedness of buses is a major problem. This paper proposes a bus crowdedness sensing system which exploits deep learning-based object detection to count the numbers of passengers getting on and off a bus and thus estimate the crowdedness of buses in real time. In our prototype system, we combine YOLOv5s object detection model with Kalman Filter object tracking algorithm to implement a sensing algorithm running on a Jetson nano-based vehicular device mounted on a bus. By using the driving recorder video data taken from real bus, we experimentally evaluate the performance of the proposed sensing system to verify that our proposed system system improves counting accuracy and achieves real-time processing at the Jetson Nano platform.

  • Convolutional Auto-Encoder and Adversarial Domain Adaptation for Cross-Corpus Speech Emotion Recognition

    Yang WANG  Hongliang FU  Huawei TAO  Jing YANG  Hongyi GE  Yue XIE  

     
    LETTER-Artificial Intelligence, Data Mining

      Pubricized:
    2022/07/12
      Vol:
    E105-D No:10
      Page(s):
    1803-1806

    This letter focuses on the cross-corpus speech emotion recognition (SER) task, in which the training and testing speech signals in cross-corpus SER belong to different speech corpora. Existing algorithms are incapable of effectively extracting common sentiment information between different corpora to facilitate knowledge transfer. To address this challenging problem, a novel convolutional auto-encoder and adversarial domain adaptation (CAEADA) framework for cross-corpus SER is proposed. The framework first constructs a one-dimensional convolutional auto-encoder (1D-CAE) for feature processing, which can explore the correlation among adjacent one-dimensional statistic features and the feature representation can be enhanced by the architecture based on encoder-decoder-style. Subsequently the adversarial domain adaptation (ADA) module alleviates the feature distributions discrepancy between the source and target domains by confusing domain discriminator, and specifically employs maximum mean discrepancy (MMD) to better accomplish feature transformation. To evaluate the proposed CAEADA, extensive experiments were conducted on EmoDB, eNTERFACE, and CASIA speech corpora, and the results show that the proposed method outperformed other approaches.

  • Multibeam Patterns Suitable for Massive MIMO Configurations

    Kentaro NISHIMORI  Jiro HIROKAWA  

     
    PAPER

      Pubricized:
    2022/07/13
      Vol:
    E105-B No:10
      Page(s):
    1162-1172

    A multibeam massive multiple input multiple output (MIMO) configuration employs beam selection with high power in the analog part and executes a blind algorithm such as the independent component analysis (ICA), which does not require channel state information in the digital part. Two-dimensional (2-D) multibeams are considered in actual power losses and beam steering errors regarding the multibeam patterns. However, the performance of these 2-D beams depends on the beam pattern of the multibeams, and they are not optimal multibeam patterns suitable for multibeam massive MIMO configurations. In this study, we clarify the performance difference due to the difference of the multibeam pattern and consider the multibeam pattern suitable for the system condition. Specifically, the optimal multibeam pattern was determined with the element spacing and beamwidth of the element directivity as parameters, and the effectiveness of the proposed method was verified via computer simulations.

  • Constant-Round Fair SS-4PC for Private Decision Tree Evaluation

    Hikaru TSUCHIDA  Takashi NISHIDE  

     
    PAPER-Cryptography and Information Security

      Pubricized:
    2022/03/09
      Vol:
    E105-A No:9
      Page(s):
    1270-1288

    Multiparty computation (MPC) is a cryptographic method that enables a set of parties to compute an arbitrary joint function of the private inputs of all parties and does not reveal any information other than the output. MPC based on a secret sharing scheme (SS-MPC) and garbled circuit (GC) is known as the most common MPC schemes. Another cryptographic method, homomorphic encryption (HE), computes an arbitrary function represented as a circuit by using ciphertexts without decrypting them. These technologies are in a trade-off relationship for the communication/round complexities, and the computation cost. The private decision tree evaluation (PDTE) is one of the key applications of these technologies. There exist several constant-round PDTE protocols based on GC, HE, or the hybrid schemes that are secure even if a malicious adversary who can deviate from protocol specifications corrupts some parties. There also exist other protocols based only on SS-MPC that are secure only if a semi-honest adversary who follows the protocol specification corrupts some parties. However, to the best of our knowledge, there are currently no constant-round PDTE protocols based only on SS-MPC that are secure against a malicious adversary. In this work, we propose a constant-round four-party PDTE protocol that achieves malicious security. Our protocol provides the PDTE securely and efficiently even when the communication environment has a large latency.

  • Energy-Efficient KBP: Kernel Enhancements for Low-Latency and Energy-Efficient Networking Open Access

    Kei FUJIMOTO  Ko NATORI  Masashi KANEKO  Akinori SHIRAGA  

     
    PAPER-Network

      Pubricized:
    2022/03/14
      Vol:
    E105-B No:9
      Page(s):
    1039-1052

    Real-time applications are becoming more and more popular, and due to the demand for more compact and portable user devices, offloading terminal processes to edge servers is being considered. Moreover, it is necessary to process packets with low latency on edge servers, which are often virtualized for operability. When trying to achieve low-latency networking, the increase in server power consumption due to performance tuning and busy polling for fast packet receiving becomes a problem. Thus, we design and implement a low-latency and energy-efficient networking system, energy-efficient kernel busy poll (EE-KBP), which meets four requirements: (A) low latency in the order of microseconds for packet forwarding in a virtual server, (B) lower power consumption than existing solutions, (C) no need for application modification, and (D) no need for software redevelopment with each kernel security update. EE-KBP sets a polling thread in a Linux kernel that receives packets with low latency in polling mode while packets are arriving, and when no packets are arriving, it sleeps and lowers the CPU operating frequency. Evaluations indicate that EE-KBP achieves microsecond-order low-latency networking under most traffic conditions, and 1.4× to 3.1× higher throughput with lower power consumption than NAPI used in a Linux kernel.

  • Detection Performance Analysis of Distributed-Processing Multistatic Radar System with Different Multivariate Dependence Models in Local Decisions

    Van Hung PHAM  Tuan Hung NGUYEN  Hisashi MORISHITA  

     
    PAPER-Sensing

      Pubricized:
    2022/03/24
      Vol:
    E105-B No:9
      Page(s):
    1097-1104

    In a previous study, we proposed a new method based on copula theory to evaluate the detection performance of distributed-processing multistatic radar systems, in which the dependence of local decisions was modeled by a Gaussian copula with linear dependence and no tail dependence. However, we also noted that one main limitation of the study was the lack of investigations on the tail-dependence and nonlinear dependence among local detectors' inputs whose densities have long tails and are often used to model clutter and wanted signals in high-resolution radars. In this work, we attempt to overcome this shortcoming by extending the application of the proposed method to several types of multivariate copula-based dependence models to clarify the effects of tail-dependence and different dependence models on the system detection performance in detail. Our careful analysis provides two interesting and important clarifications: first, the detection performance degrades significantly with tail dependence; and second, this degradation mainly originates from the upper tail dependence, while the lower tail and nonlinear dependence unexpectedly improve the system performance.

121-140hit(3318hit)