This paper investigates the electron density distributions in the inversion layer of Ta gate, Al2O3 insulator and Si substrate MOSFETs. Schrödinger/Poisson model is used to analyze the quantum effects of the inversion layer. The electron density distributions of Ta/Al2O3 MOSFETs are compared with those of Poly-Si/SiO2 MOSFETs. As a result, the electrical thickness of the gate insulator is increased from 5.42 to 9.21% due to the quantum effects. It is found that the dielectric constants stlongly affect the electron density in the inversion layer.
Improved transcription method of graphene saturable absorber mirror (GSAM) is tested to enhance visible pulse fiber laser oscillation properties. When a graphene thin film on a dielectric multi-layered mirror is soaked in nitric acid solution for washing process, the mirror suffers from a deterioration of transmission spectrum, or a detachment of dielectric multilayer from a mirror substrate. New method is the way that a dielectric multi-layered mirror is not washed in nitric acid directly and the transcribed graphene on a silica glass sheet is just put on a dielectric multi-layered mirror with opponent situation. Visible pulse laser oscillation in a Pr-doped double-clad structured waterproof fluoride glass fiber was tested with two types of GSAM whose dielectric multilayered parts are directly (GSAM-I) or not directly (GSAM-II) washed in nitric acid solution. The maximum output average power with GSAM-II was measured to be 9.52 mW at 644 mW GaN-LD excitation, on the other hand, 2.63 mW for GSAM-I and the slope efficiency of GSAM-II one was also improved as four times as GSAM-I one. Therefore, it is considered that the new washing process of transcribed graphene is effective for keeping the mirror properties and enhancement of the laser properties.
This paper presents a novel prototype of a soft-switching resonant dc-dc power converter with high breakdown-voltage Gallium Nitride Heterojunction-Field-Effect-Transistor (GaN-HFET) for inductive power transfer (IPT) systems. The edge-resonant zero voltage soft-switching (ZVS) operation using lossless snubbing capacitors is essential for effective reduction of switching power losses and noises with low threshold voltage of the GaN-HFET. The excellent performances such as high efficiency, low switching noises and normally-off operation are originally demonstrated in experiment of a 950W prototype by comparing with a super-junction (SJ)-MOSFET based prototype under the fair conditions of breakdown-voltage and current rating. The feasibility of GaN-HFET-applied IPT-ZVS converter is discussed from a practical point of view.
The objective of this study is to measure the contact force between an infant tongue and an artificial nipple and examine whether it is possible to estimate the amount of breast milk intake using several parameters calculated from the force measurements. We installed force sensors at the tip and root of an artificial nipple and developed a system for measuring the contact force between an infant tongue and the artificial nipple. The system measures the force of the tongue simply by inserting the nipple in the oral cavity of the infant and outputs time-historical waveforms. In the force measurements, waveforms of mutually different phases are output from the two sensors, and the peristaltic-like movement of the tongue is successfully monitored. Parameters from the force measurements correlating to the amount of breast milk intake were the maximum force and the sucking interval. These findings suggest it may be possible to estimate the amount of breast milk intake just by measuring the tongue force of the infant.
The sound source localization problem (identifying the distance and the direction from sound source) has been important in various engineering fields and many approaches have been developed, e.g., MUSIC (MUltiple SIgnal Classification). However, they often require a microphone array with multiple microphone elements to obtain such information. Meanwhile, since the distance to a target is also important, many distance measurement methods with sound have been proposed. We proposed an acoustic distance measurement (ADM) method based on interference between transmitted and reflected waves, which could measure distance at a short range. Existing ADM methods based on interference make errors due to the measuring system from the loudspeaker to the microphone. To remove the effect of the measuring system, a cross-spectral analysis was applied to the observed wave and the pseudo-observed wave, convolving the transmitted wave with the impulse response of the measuring system a priori measured. Attaching a microphone to a target causes multiple reflections (interference between the sound source and the target). This paper describes a method based on the phase interference to estimate the distance between a sound source and a target (reflector), using a single-channel cross-spectrum between the observed and the pseudo-observed waves. The validity and effectiveness of the proposed method is confirmed through simulation and experiment.
Specular highlight, which is a direct reflection component of illumination light, is known to be an obstacle when reading color-codes of resistors using image recognition. We propose a method for avoiding the influence of specular highlight through image processing. We have set plural strip-shaped areas on color-codes and extract the color by selecting areas of smaller influence of reflection. We have implemented an algorithm of reading color-codes and conducted reading experiments of resistors having various angle of rotation, which have changing areas of specular highlights. As a result, we have confirmed an identification rate of 99%. We also discuss the changes of the influence of specular highlights due to the rotation of the resistors.
The employer needs to determine a work shift table, when the store employs many part-timers. The shift table is the quota table of the employees who work at the store in a certain period. In determining a target work shift table, it is desirable to take in all part-timer's requests and to make total part-timer's wages low as much as possible. However, it is difficult to determine the shift table because of many variables, which number is the product of the service shifts and the part-timers, and the part-timer's requests are qualitatively expressed.
This paper presents decision support system for the work shift table according to the requests and wages for part-timers. First of all, this system changes the qualitative values of a part-timer's requests into the quantitative values. Next, the ideal total value of requests is calculated from the shift table created by integer programming with branch-and-bound method. The ideal total value of wages is calculated through the same method. Finally, the candidates of the shift table according to the situation are created by the weighting coefficient method based on two kinds of ideal total value, request table, wage table, and restrictions. Results of an experiment showed the validity of the proposed system.
Ultrasonic waves were very often used to measure the distance to a target. Authors proposed a distance measurement method based on phase interference between the transmitted and reflected audible sounds. This paper describes a new trail on the distance measurement using ultrasonic waves for close range by using a single transducer.
This research evaluates a WiFi based positioning method for indoor evacuation guidance system using Bayesian estimation method. Conventional researches have not sufficiently supposed irregular operation of APs (Access Point) which often end up output WiFi signal caused by power saving mode. In this research, the Bayesian estimation method is evaluated in practical field including various APs.
In gas and water utilities, the spread of ultra-low power Wireless-Smart Utility Networks (Wi-SUN) has been predicted. This paper proposes a novel MAC protocol (F-RIT protocol) complied with the RIT in IEEE 802.15.4e standards to implement the wireless SUN in the gas and water utilities effectively. The proposed protocol is compared with CSL in IEEE 802.15.4e in terms of power consumption and success rate of communication link establishment. Theoretical and simulated evaluation results show the effectiveness of the proposed protocol under conditions of high terminal density and highly communication link request. In addition, a potential of F-RIT protocol regarding improvement of performance and expansion of application is described.
We have created a mixed reality concert application using Alice, a 3d rapid prototyping programming environment, in which musical instruments are arranged around a virtual conductor (in this case the user) located at their center. A user-conductor can use a smartphone as a simplified baton, pointing at a preferred instrument and tapping a button to start playing. The volume and panning of a selected instrument can be adjusted by simply tilting and rolling the smartphone. When selected, an instrument is jiggled or its components dilated and contracted, and a spotlight illuminates it until the instrument is muted, providing conductor and audience with visual cues about the ensemble. Unlike other systems, ours does not require user or equipment to be placed at specific locations (contrasted with Kinect, Wii sensors, or camera-based tracking systems), and there is no issue regarding room lighting (such as digital camera-based tracking systems or Kinect), nor interference with other players or obstacles. The goal of using different equipment as a conductor's baton is to allow nonexpert users to lead a realtime concert within a cyberworld. Synchronization of gestures with music and animation has been one of the biggest challenges in many systems we surveyed, although ours showed only minimal delays. We compared user experience with a contemporary commercial game, receiving acceptable ratings from the participants.
In this study, the authors have developed wind power and solar power facilities in their “Simulated Micro Grid System for Education”. The wind power simulation system has adopted a squirrel-cage type three-phase induction motor as a generator. The rotational speed of the three-phase induction motor is controlled by another inverter fed motor, which simulates the wind power. This facility is able to measure the generated power and the rotational speed. The solar power simulation system has adopted a robot arm to which a light bulb is attached. The robot arm is controlled to follow the orbit as the sun, so that the solar power is simulated. Similarly, this facility is able to measure the generated power.
We evaluated the temperature change of facial parts as affected by mental work-load (MWL) using infrared thermography. Under MWL, autonomic nerves are active, and the skin surface temperature changes with muscular contraction. In particular, the nasal part of the face experiences the most intense change. Based on this, in previous studies MWL was evaluated by using nasal skin temperature. However, we considered whether other parts of the face experience temperature change under MWL. Therefore, in this study, to identify which other parts of the face experience temperature change, we performed an experiment to acquire facial thermal images when subjects perform a mental arithmetic calculation task. Our results indicate that, in addition to the nasal part, the temperatures around the lips and cheek might also increase under MWL.
Real Coded Genetic Algorithm (RCGA) is one of evolutionary algorithm for handling real-valued vector. The RCGA is much better than conventional GA handling with bit strings as genotype. Various dedicated hardware for GA have been proposed for speedup or the applications of evolvable hardware. However, many of these hardware based on the bit strings GA or the compact GA. Therefore, there are few reports of RCGA hardware. In this paper, we propose an architecture of RCGA processor. The proposed processor conform to the Just Generation Gap (JGG) as a generation alternation model of RCGA. In addition, the processor is implemented the Real coded Ensemble Crossover (REX). One of the features of proposed processor is that the REX circuit can be implemented with small circuit scale because the circuit resources effectively shared such as arithmetic units. Furthermore, the second feature is to evaluate the offspring using by the soft macro CPU. Thus, the versatility is enhanced because the evaluation function that depend on problems can change by rewriting of software. Moreover, they are implemented in parallel for speeding up. The proposed processor is expected in embedded field applications because of it can be implemented in one chip FPGA.
In this paper, to improve the search performance and usability of Cuckoo Search (CS), we develop a new Adaptive Cuckoo Search (ACS) based on evaluation and control of its search state by adjusting one of its parameters. ACS consists of a new evaluation indicator and a feedback control mechanism. Using the results of the quantitative analysis of the relationship between the parameter and random numbers in Lévy Flight, we clarify the effects of the parameter on the search dynamics of CS in terms of the metaheuristics strategy (diversification / intensification). After the analysis, the indicator which evaluates the search state is defined. The mechanism makes an ideal state (a target of the indicator) and controls the search state to the ideal state by adjusting the parameter. Overall, ACS is expected to improve the search performance of CS by adequately realizing diversification and intensification during a search. The performance and adaptability of ACS are verified through numerical simulations for 9 typical benchmark functions.
This study applies a circuit solution detecting technique by the particle swarm optimization (PSO) to search the maximum power point (MPP) in the photovoltaic (PV) model. A task of the proposed method is to find system parameters which produce the maximum power, however, finding the MPP requires an information of the circuit solution. The proposed method consists of two PSOs that search the MPP and the circuit solution, respectively. We confirm that the proposed method can obtain the parameters with same accuracy as the exact calculation in a less amount of iterations.