The 400GbE standard has been established to treat the increasing Internet traffic because of IoT devices and teleworking. In the 400GbE, PAM4 codes are adopted in addition to conventional NRZ codes. For a high-speed, long-haul, and complex modulated communication, a waveform signal is degraded by an optical dispersion on a fiber. The receiver utilizes electrical dispersion compensators (EDCs) to compensate for waveforms degraded by transmission lines. Continuous-time linear equalizers (CTLEs) are widely used in EDCs because of their small circuit size. EDCs with CTLEs are studied actively for PAM4 optical communication systems. We propose a CTLE design methodology based on a step response analysis. Appropriate compensation ranges for PAM4 signals are derived by the transfer function of degradation and CTLE mathematical models. From the verification results of circuit simulations with CTLEs designed by the proposed methodology, we have clarified the appropriate CTLE compensation strength for degraded waveform signals. It is possible to design a suitable CTLE for PAM4 signals using the proposed methodology.

A circuit of simultaneous data and power transfer systems exploiting frequency shift keying (FSK) in the magnetic resonance wireless power transfer (MR-WPT) circuit is proposed. The proposed circuit attains FSK based on the frequency characteristics of the MR-WPT circuits known as frequency splitting phenomenon and contains a frequency control circuit using a phase-locked loop to enhance robustness against a fluctuation of a load and a coupling coefficient between transfer coils. The proposed circuit is implemented on the designed printed circuit board with off-the-shelf integrated circuits. In addition, an FSK demodulator using an FPGA is also presented and implemented. Experiments reveal the feature of output power insensitive to the space between coils. The proposed circuit achieved transmitting data at a bit rate of 57.6 kbps and delivering 0.60-W power with 32.4% efficiency at the coupling coefficient between transfer coils of 0.36 for the 1.01-Ω ohmic load.

In order to compensate for the non-linearity of the electronic device, an exponentiation conversion circuit that can change the power exponent to any value has been proposed. The exponentiation conversion circuit multiplies the logarithmically converted input signal by the power exponent value to perform exponential conversion. As a result, we can obtain the power function characteristic of the power exponent value. This circuit is a small-scale circuit that utilizes the exponential characteristics of the MOSFET subthreshold region. In the conventional circuit, expansion of the signal dynamic range has been an issue. In this paper, it was confirmed by simulation that the signal dynamic range is expanded by optimizing the current density of MOSFETs. In addition, the linearity of the multiplication circuit was improved by introducing operational amplifier. By evaluating its prototype IC with 0.6 µm CMOS process, we confirmed the signal dynamic range was expanded from 6.90 dB to 36.7 dB in current signal input and, the power exponent value can change in the range of -0.068 to 6.2.

The three-phase diode rectifiers offer several desirable features such as a simple topology, low high-frequency noise, high reliability, and high environmental durability. However, the rectifiers produce undesirable lower-order harmonics in the input current. To overcome this problem, the author describes a three-phase diode rectifier, which meets to the regulations of JIS C 61000-3-2 (Class A). In this paper, the author validates of the three-phase capacitor-input and choke-input diode rectifiers (1.5kW and 7.0kW on 200V/50Hz) through simulation and experimental results.

This paper developed a receptor cell model that mimics the receptor cells' function of living organisms. The receptor cell model converts the signal input of the sensor into an oscillating pulse waveform. The oscillation frequency of the receptor cell model varies according to the sensory input intensity. Firstly, the authors construct the receptor cell model by discrete circuit. The circuit was described using circuit simulation and compared with the experimental result. Also, we measure the frequency characteristics utilizing a pressure sensor and an optical sensor. The result shows that the receptor cell model could vary from 300 Hz to 600 Hz according to the sensory input intensity. Secondly, the authors propose the receptor cell model by the integrated circuit. Experimental results showed that the receptor cell model's oscillation frequency changed from 370 Hz to 890 Hz. As a result, the proposal receptor cell model could output the oscillating pulse waveform dependent on sensor input intensity.

We have been presented the accurate complex permittivity method for small diameter dielectric rod samples using the 50GHz band TM₀₁₀ mode cavity resonator with small sample insertion holes. However, the measurement efficiency is not enough high to evaluate various samples due to the difficulty of sample insertion into the holes. In this paper, a novel insertion procedure for a small diameter dielectric sample is proposed using the insertion support tube to improve measurement efficiency. And, the suitable placement technique for the small dielectric sample is studied experimentally. Moreover, the complex permittivity of 4 kinds of 20 thermoplastic resin rods with a diameter of 0.4mm is measured efficiently and accurately around the 45GHz band.

HF and LF/HF, which are parameters of the frequency domain of the electrocardiogram R-R interval time series, are general index of the autonomic nervous activity balance. Most wristwatch-type heart rate monitors measure heart rate from sphygmograph and interpolate missing data. These are the causes of reducing the calculation accuracy of LF and HF. The purpose of this study is to propose a method for estimating LF and HF calculated from the ECG R-R interval time series from the heart rate time series at 1-second intervals measured by a wristwatch-type heart rate monitor. 670 data-set with a length of 120 seconds measured simultaneously with an electrocardiogram and a wristwatch-type heart rate monitor during standing cooking operation, up-right standing, watching slide show in standing posture, and resting supine position were used. 70% dataset were used for modeling, and remaining 30% were used for evaluating model. As a result, the coefficient of determination of LF and HF were 0.441 and 0.467 respectively in the one-variable polynomial regression model. The coefficient of determination of LF and HF were 0.557 and 0.644 respectively in the multivariable regression model, based on Random Forest and time domain indices.

We propose a system to manage electric craft tool usage and monitor of leaving in use. When a user uses tool, the system performs authentication process. Therefore, only authorized user can use tool. When the system recognizes leaving in use, automatically turns off the power of tool. All usage history and information of leaving in use will be recorded. And, that user’s usage authority will be removed automatically. We used a soldering iron as a power tool in this study.

When user starts using tool, they use ID card to authenticate. A power supply for tool is controlled by a solid-state relay. Attach a photoreflector to the iron stand to recognize state of the soldering iron. Leaving in use is state that soldering iron continues to be placed on an iron stand or taken out of it. If leaving in use occurs, tool will be automatically turned off. This will prevent occurrence accidents and injuries from occurring.

We checked to see if the system could manage the use of tools. Only authorized users were able to use tools and usage history was recorded. It could correctly detect the tool being left on and automatically turn off the tool. It could also record information on being left unattended and remove the user’s usage authority. Subsequently, we asked actual users to use this system. They could use it correctly. However, this system was not recognized when one user was replaced by another user while the tool in use. However, the system was able to detect the tool being left unattended regardless of the user.

Recently a shortage of staff and engineers in a water supply utility has been a considerable concern. Technological assistance is needed for a systematic inheritance of the knowledge of skilled operators to continue a stable water supply for the future. An operation of a water supply system involves multiple objectives to be satisfied, for example, smoothing of flows and settling variation ranges of levels of service reservoirs. Skilled operators have judged actual operations involving the balance between the objectives based on their experience. To construct a practical optimal operation scheduling model of a water supply system, we propose a method that determines an optimal set of parameters on balance between the objectives in the scheduling model. The proposed method minimizes the difference between the operation schedules and the operation records to reproduce practical operations of skilled operators in terms of balance. A case study confirmed that the parameter set determined by the proposed method replicated the objective balance better than a reference parameter set and was more robust to the elapsed time for more than a half year.

A class of affine T-S fuzzy models with uncertainty is considered in this paper. Compared with the T-S fuzzy model which is widely used in fuzzy control systems, affine T-S fuzzy model is regarded as a more effective model to describe the dynamics of the system concerned. However, the difficulty is how to handle the affine term in the model. In this paper, following a partition of state space that enables us to employ the S-procedure in an effort to deal with the affine term, a switching-type controller is proposed. The controller contains an uncertainty observer that is used to tackle the existence of the uncertainty and an adaptive law that is used to deal with others that are not covered by the uncertainty observer. In additions, examples are provided in order to demonstrate the effectiveness of the approach proposed in the paper.

In recent years, in the field of artificial life, research has been actively conducted to model the behavior of living organisms on a computer and elucidate the evolutionary mechanism. It is known that real Aomon damselflies perform long-term mating before the start of spawning activity to restrain females in order to prevent sperm from being scraped from other males. It has also been confirmed that mating time is longer in an environment with many males. In this study, we try to create an agent-based model that strongly reflects the actual ecology in order to observe the evolution of male mating time. Then, the created model is used to investigate changes in mating time in an environment with many males.

In this study, we developed an educational support robot to teach English vocabulary by incorporating tips on how to remember words such as etymology. In the experiments, we found that the robot improved test scores by providing more opportunities for output and displaying information in organized way.

There are roughly two methods for estimating optical flow. One is the gradient method and the other is the block matching method. Each method has a few problems. In the gradient method, it is difficult to estimate optical flow when images include a noise and the difference in brightness between adjacent pixels is small. In the block matching method, an accuracy depends on the block division method and it isn't able to deal with a non-rigid body. Therefore, it is difficult to estimate the optical flow in a video that is easily affected by noise and exists deforming objects such as medical images. For each of these problems, we propose a method for estimating optical flow that is robust especially for object deformation while concerning a noise. The proposed method is based on the block matching method and has two improvements. One is to use Superpixels for block division. The other is to use the phase correlation for displacement estimation. Furthermore, we extend it by deep learning to be robust for a complicated change. The experimental results show the proposed method was robust to the object deforming in the medical image dataset.

An extended Multiobjective Evolutionary Algorithm Based on Decomposition (MOEA/D) with adaptive weight adjustment is proposed in this letter. The proposed method facilitates the search on the constraint boundary by adaptively adjusting the weights in the search process. The search performance of the proposed method is shown to be superior to that of the conventional method through numerical experiments using a constrained convex optimization problem.