The separating redundancy is an important property in the analysis of the error-and-erasure decoding of a linear block code. In this work, we investigate the separating redundancy of the duals of first-order generalized Reed-Muller (GRM) codes, a class of nonbinary linear block codes that have nice algebraic properties. The dual of a first-order GRM code can be specified by two positive integers m and q and denoted by R(m,q), where q is the power of a prime number and q≠2. We determine the first separating redundancy value of R(m,q) for any m and q. We also determine the second separating redundancy values of R(m,q) for any q and m=1 and 2. For m≥3, we set up a binary integer linear programming problem, the optimum of which gives a lower bound on the second separating redundancy of R(m,q).

Unmanned aircraft systems (UASs) have been developed and studied as temporal communication systems for emergency and rescue services during disasters, such as earthquakes and serious accidents. In a typical UAS model, several unmanned aerial vehicles (UAVs) are used to provide services over a large area. The UAV is comprised of a transmitter and receiver to transmit/receive the signals to/from terrestrial stations and terminals. Therefore, the carrier frequencies of the transmitted and received signals experience Doppler shifts due to the variations in the line-of-sight velocity between the UAV and the terrestrial terminal. Thus, by observing multiple Doppler shifts from different UAVs, it is possible to detect the position of a user that possesses a communication terminal for the UAS. This study aims to present a methodology for position detection based on the least-squares method to the Doppler shift frequencies. Further, a positioning accuracy index is newly proposed, which can be used as an index for measuring the position accurately, instead of the dilution-of-precision (DOP) method, which is used for global positioning systems (GPSs). A computer simulation was conducted for two different flight route models to confirm the applicability of the proposed positioning method and the positioning accuracy index. The simulation results confirm that the parameters, such as the flight route, the initial position, and velocity of the UAVs, can be optimized by using the proposed positioning accuracy index.

Data replication in cloud storage systems brings a lot of benefits, such as fault tolerance, data availability, data locality and load balancing both from reliability and performance perspectives. However, each time a datanode fails, data blocks stored on the failed datanode must be restored to maintain replication level. This may be a large burden for the system in which resources are highly utilized with users' application workloads. Although there have been many proposals for replication, the approach of re-replication has not been properly addressed yet. In this paper, we present a deferred re-replication algorithm to dynamically shift the re-replication workload based on current resource utilization status of the system. As workload pattern varies depending on the time of the day, simulation results from synthetic workload demonstrate a large opportunity for minimizing impacts on users' application workloads with the simple algorithm that adjusts re-replication based on current resource utilization. Our approach can reduce performance impacts on users' application workloads while ensuring the same reliability level as default HDFS can provide.

This study proposes a multiple-output differential-input operational transconductance amplifier-C (MODI OTA-C) filter with an impedance scaler to detect cardiac activity. A ladder-type fifth-orderButterworth low-pass filter with a large time constant and low noise is implemented to reduce coefficient sensitivity and address signal distortion. Moreover, linearized MODI OTA structures with reduced transconductance and impedance scaler circuits for noise reduction are used to achieve a wide dynamic range (DR). The OTA-based circuit is operated in the subthreshold region at a supply voltage of 1 V to reduce the power consumption of the wearable device in long-term use. Experimental results of the filter with a bandwidth of 250 Hz reveal that DR is 57.6 dB, and the harmonic distortion components are below -59 dB. The power consumption of the filter, which is fabricated through a TSMC 0.18 µm CMOS process, is lower than 390 nW, and the active area is 0.135 mm2.

A new hybrid brain-computer interface (BCI), which is based on sequential controls by eye tracking and steady-state visual evoked potentials (SSVEPs), has been proposed for high-speed spelling in virtual reality (VR) with a 40-target virtual keyboard. During target selection, gaze point was first detected by an eye-tracking accessory. A 4-target block was then selected for further target selection by a 4-class SSVEP BCI. The system can type at a speed of 1.25 character/sec in a cue-guided target selection task. Online experiments on three subjects achieved an averaged information transfer rate (ITR) of 360.7 bits/min.

A hexagonal waveguide branch line coupler suitable for additive manufacturing is proposed in this study, and its design method is elucidated. The additive manufactured Ka-band coupler exhibits characteristics similar to those of a machined coupler, but its weight and cost are reduced by 40% and 60%, respectively. Its effectiveness is also confirmed in this study.

The authors have proposed a new type of flexible and printable 12GHz-band phase shifter using polymer actuator for the first time. Polymer bending actuator was used as a termination device of a reflection-type 3-dB, 90° hybrid coupler as the phase-shift control unit which controls the electrical length of the waveguide for microwave signals by the applied bias voltage. The microstrip line circuit of the device has been fabricated using low-cost screen printing method. Polymer bending actuator having three-layer stacking structure, in which an ionic liquid electrolyte layer is sandwiched with two conductive network composite layers, was formed by wet processes. The authors have confirmed that the phase shift could be controlled in analog by low driving voltages of 2-7 V for the actuator with a insertion loss of 2.73 dB. This phase shifter can be integrated with flexible patch antenna and the current flexible polymer electronics devices such as transistors.

A wideband design of the waveguide short-slot 2-plane coupler with 2×2 input/output ports is designed, fabricated, and evaluated. Using coupling coefficients of complementary propagating modes which are TE11, TE21, and TE30 modes, the flatness of the output amplitudes of 2-plane coupler is improved. The coupler operates from 4.96GHz to 5.27GHz (bandwidth 6.1%) which is wider than the former coupler without considering the complementary propagating mode from 5.04GHz to 5.17GHz (bandwidth 2.5%).

This paper presents the design of a capacitive coupler for underwater wireless power transfer (U-WPT) focusing on kQ product. Power transfer efficiency hinges on the coupling coefficient k between the couplers and Q-factor of water calculated from the complex permittivity. High efficiency can be achieved by handling k and the Q-factor effectively. First, the pivotal elements on k are derived from the equivalent circuit of the coupler. Next, the frequency characteristic of the Q-factor in tap water is calculated from the measured results. Then, the design parameters in which kQ product has the maximal values are determined. Finally, it is demonstrated that the efficiency of U-WPT with the capacitive coupling designed by our method achieves approximately 80%.

In parallel processing applications, a few worker nodes called “stragglers”, which execute their tasks significantly slower than other tasks, increase the execution time of the job. In this paper, we propose a network switch based straggler handling system to mitigate the burden of the compute nodes. We also propose how to offload detecting stragglers and computing their results in the network switch with no additional communications between worker nodes. We introduce some approximate techniques for the proxy computation and response at the switch; thus our switch is called “ApproxSW.” As a result of a simulation experiment, the proposed approximation based on task similarity achieves the best accuracy in terms of quality of generated Map outputs. We also analyze how to suppress unnecessary proxy computation by the ApproxSW. We implement ApproxSW on NetFPGA-SUME board that has four 10Gbit Ethernet (10GbE) interfaces and a Virtex-7 FPGA. Experimental results shows that the ApproxSW functions do not degrade the original 10GbE switch performance.

This letter addresses the problem of space-time adaptive processing (STAP) for airborne nonuniform linear array (NLA) radar using a generalized sidelobe canceller (GSC). Due to the difficulty of determining the spatial nulls for the NLAs, it is a problem to obtain a valid blocking matrix (BM) of the GSC directly. In order to solve this problem and improve the STAP performance, a BM modification method based on the modified Gram-Schmidt orthogonalization algorithm is proposed. The modified GSC processor can achieve the optimal STAP performance and as well a faster convergence rate than the orthogonal subspace projection method. Numerical simulations validate the effectiveness of the proposed methods.

When the automated driving cars are in widespread usage, traffic will coexist with prioritized vehicles (e.g., ambulances, fire trucks, police vehicles) and automated driving cars. Automated driving cars are expected to be safer and lower stress than manual driving vehicles because of passengers paying less attention to driving. However, there are many challenges for automated driving cars to get along with surrounding transport participants. In particular, when an ambulance is driving into an intersection with the red traffic signal, the automated driving car is required to deal with a situation differently from normal traffic situations. In order to continue safe driving, it is necessary to recognize the approach of the ambulance at an earlier time. Possible means of recognizing ambulances include siren sound, rotating red lights and vehicle to vehicle communication. Based on actual traffic data, the authors created a mathematical model of deceleration for giving way and consider the status of suitable behavior by automated driving cars. The authors calculate the detection distance required to take suitable action. The results indicate that there are advantages in vehicle to vehicle communication in detecting ambulances by automated driving cars.

In small-aperture high frequency surface wave radar, the main-lobe clutter all can be seen as a more severe space spread clutter under the influence of the smaller array aperture. It compromises the detection performance of moving vessels, especially when the target is submerged in the clutter. To tackle this issue, an improved spread clutter estimated canceller, combining spread clutter estimated canceller, adaptive selection strategy of the optimal training samples and rotating spatial beam method, is presented to suppress main-lobe clutter in both angle domain and range domain. According to the experimental results, the proposed algorithm is shown to have far superior clutter suppression performance based on the real data.

With the evolution of autonomous distributed systems such as smart cities, autonomous vehicles, smart control and scheduling systems there is an increased need for approaches to manage the execution of services to deliver real-time performance. As Cloud-hosted services are increasingly used to provide intelligence and analytic functionality to Internet of Things (IoT) systems, Quality of Service (QoS) techniques must be used to guarantee the timely service delivery. This paper reviews state-of-the-art QoS and Cloud techniques for real-time service delivery and data analysis. A review of straggler mitigation and a classification of real-time QoS techniques is provided. Then a mathematical framework is presented capturing the relationship between the host execution environment and the executing service allowing the response-times to predicted throughout execution. The framework is shown experimentally to reduce the number of QoS violations by 21% and provides alerts during the first 14ms provide alerts for 94% of future violations.

We propose a weighted subtask controller and sufficient conditions for boundedness of the controller both velocity and acceleration domain. Prior to designing the subtask controller, a task controller is designed for global asymptotic stability of task space error and subtask error. Although the subtask error converges to zero by the task controller, the boundedness of the subtask controller is also important, therefore its boundedness conditions are presented. The weighted pseudo inverse is introduced to relax the constraints of the null-space of Jacobian. Using the pseudo inverse, we design subtask controller and propose sufficient conditions for boundedness of the auxiliary signal to show the existence of the inverse kinematic solution. The results of experiments using 7-DOF WAM show the effectiveness of the proposed controller.

This paper considers a multi-user large-scale multiple-input multiple-output (MIMO) system with single cell working in full-duplex mode. Maximum ratio combining/maximum ratio transmission (MRC/MRT) is applied to maximize the output signal to noise ratio (SNR) of the receiver. Then we deduce the asymptotic uplink and downlink sum rate in full-duplex mode by using the large number theorem, also giving the comparison of traditional half-duplex and full-duplex. Besides, we analyze the influence of Doppler shift on the performance of the system. Finally, the change of the system performance on the user velocity is illustrated.

To realize three-dimensional (3D) optical interconnection on large-scale integration (LSI) circuits, layer-to-layer couplers based on Si-photonics platform were reviewed. In terms of optical cross talk, more than 1 µm layer distance is required for 3D interconnection. To meet this requirement for the layer-to-layer optical coupler, we proposed two types of couplers: a pair of grating couplers with metal mirrors for multi-layer distance coupling and taper-type directional couplers for neighboring layer distance coupling. Both structures produced a high coupling efficiency with relatively compact (∼100 µm) device sizes with a complementary metal oxide semiconductor (CMOS) compatible fabrication process.

Frequency chirp of a semiconductor laser is controlled by using hybrid modulation, which simultaneously modulates intra-cavity loss and injection current to the laser. The positive adiabatic chirp of injection-current modulation is compensated with the negative adiabatic chirp created by intra-cavity-loss modulation, which enhances the chromatic-dispersion tolerance of the laser. A proof-of-concept transmission experiment confirmed that the hybrid modulation laser has a larger dispersion tolerance than conventional directly modulated lasers due to the negative frequency chirp originating from intra-cavity-loss modulation.

A vertex subset F ⊆ V(G) is called a cyclic vertex-cut set of a connected graph G if G-F is disconnected such that at least two components in G-F contain cycles. The cyclic vertex connectivity is the cardinality of a minimum cyclic vertex-cut set. In this paper, we show that the cyclic vertex connectivity of the trivalent Cayley graphs TGn is equal to eight for n ≥ 4.

For the reconstruction of the feedback polynomial of a synchronous scrambler placed after a convolutional encoder, the existing algorithms require the prior knowledge of a dual word of the convolutional code. To address the case of a dual word being unknown, a new algorithm for the reconstruction of the feedback polynomial based on triple correlation characteristic of an m-sequence is proposed. First, the scrambled convolutional code sequence is divided into bit blocks; the product of the scrambled bit blocks with a dual word is proven to be an m-sequence with the same period as the synchronous scrambler. Second, based on the triple correlation characteristic of the generated m-sequence, a dual word is estimated; the generator polynomial of the generated m-sequence is computed by two locations of the triple correlation peaks. Finally, the feedback polynomial is reconstructed using the generator polynomial of the generated m-sequence. As the received sequence may contain bit errors, a method for detecting triple correlation peaks based on the constant false-alarm criterion is elaborated. Experimental results show that the proposed algorithm is effective. Ulike the existing algorithms available, there is no need to know a dual word a priori and the reconstruction result is more accurate. Moreover, the proposed algorithm is robust to bit errors.