Electronics and Communications in Japan最新文献

MicroRNA (miRNA), a type of non-coding RNA, is known to suppress the expression of target genes and there is an increasing number of studies analyzing various miRNAs in cancer. In an integrated analysis of miRNA and gene expressions, it is often difficult to obtain a significant result with a small amount of data. In this study, we proposed a method that allows integrated analysis even with a small amount of miRNA and gene expression data, and examined its validity. The method is based on a group comparison between target genes having specific functions controlled by a specific miRNA and a background group of randomly selected genes. We conducted a simulation to verify the validity of the proposed method. The simulation results indicated that the method can detect significant differences in expression of target genes controlled by a miRNA showing significant expression change. We then applied the proposed method to real data derived from multiple myeloma cells. As a result, some functions were detected as significantly changed due to a significant change of miRNA.

Conventionally, the adaptive body area for prism adaptation (PA) has been limited to the visible area of prism glasses, especially the unilateral upper limbs. In this study, we developed a virtual reality system that extends PA's adaptive body area. This system sets the visible area of the target and introduces a symbolic representation of the body position to realize a head position adaptation task. As a result, the develped system generates PA not to individual body parts but to a collection of multiple motor units. Furthermore, experimental results in healthy subjects showed that the head position adaptation task could generate PA in the upper trunk system (The upper trunk system is defined as a system consisting of the upper trunk, head, and upper extremities) and displace it to the left anteriorly. Therefore, the head position adaptation task is expected to be effective for the postural correction of USN patients with upper trunk system tilt to the right posteriorly. Moreover, the developed system has potential applications in a wide range of fields, such as detecting cerebellar disorders.

Intelligent-PID (i-PID) control proposed by Fliess is a simple control algorithm. The controller is designed based on ultra-local model, and consisted of PID type controller and derivatives of reference signal and controlled variables. Authors have considered discrete i-PID controller and its properties, and one of the result was that PD controller was sufficient in discrete time domain. In discrete i-PID controller, PD type controller is still required to ensure convergence of controlled error to zero, and PD type parameters affects convergence property, fast-response property and stability. In this paper, predictive functional control (PFC) based on an ultra-local model is proposed. By introducing of PFC, controlled variable converge to reference value without PD type controller. User-specified parameters of the proposed controller is smaller than the conventional i-PID controller. Characteristics of the proposed controller are compared with discrete i-PID controller by numerical examples.

Advances in microfabrication technology have enabled electron beam lithography (EB lithography) systems to produce microfabrication on the order of 10 of nanometers. Using this technology, we have fabricated nanogap electrodes that can generate large electric fields at low voltages. The gap between the tips of the fabricated electrodes is 100 nm, and the curvature of each tip is 50 nm. The device was confirmed to work as an electronic vacuum gauge, the device successfully measured vacuum from 10⁻³ to 1 Pa at the electrode voltage of 3 V.

In this study, we proposed a cuff-less blood pressure measurement using a medical tape sensor with an embedded hetero-core optical fiber. The tape sensor pasted on the skin can directly detect pulse wave signals with a simple measuring device. Pulse transit time (PTT) was obtained from the time difference between the two pulse waveforms at the neck and foot. Systolic blood pressure (SBP) was estimated from PTT and the regression equation. The result shows that the maximum prediction error was 3.8 mmHg in five healthy young subjects. The SBP data were evaluated using a Bland-Altman method to assess the agreement of SBP data estimated by the proposed method with those measured by the cuff-based electronic sphygmomanometer. The mean ± 1.96 standard deviation of the estimated SBP against the reference was −1.3 ± 5.1 mmHg. The results show that the proposed noninvasive blood pressure measurement method can measure blood pressure, and its accuracy is comparable to that of the cuff-based electronic sphygmomanometer.

In this study, the gas pressure dependence of optical and mechanical characteristics in reactive sputtered SiCO thin films for optical guided-wave pressure sensors was experimentally investigated. Thin films were fabricated by varying the gas pressure from 0.3 to 1.0 Pa at an oxygen flow ratio of 6%, and the gas pressure dependences was clarified. As the gas pressure increased, the optical bandgap of the SiCO thin film increased, resulting in a transparent SiCO films. On the other hand, the refractive index, young's modulus, and hardness decreased with increasing gas pressure. Combining this dependence with the oxygen inflow ratio dependence of the previous study, the first-order approximation formula for the gas pressure and oxygen flow rate ratio for various film characteristics was obtained. Based on this equation, trajectories of equal bandgaps and equal young's moduli on the oxygen flow ratio—gas pressure plane were created on the oxygen influx ratio-gas pressure coordinates, making it easy to fabricate waveguides with desired characteristics.

This paper proposes an analytical calculation method of frequency characteristics of DC input impedances of an IPM motor drive system for design and stability analysis by the impedance method. The proposed method is based on an averaged frequency model linearized at an operating point. The developed small-signal model considers control principles and mechanical perturbations. It is an analog and digital mixed model which is controlled by a digital signal processor system. Analysis examples of frequency characteristics for the impedance method by the proposed method are investigated and validated analytically and experimentally.

In this study, iron oxide thin films are prepared under various heat treatment conditions, and their crystal structures and moisture-sensitive characteristics were evaluated to clarify the usefulness of iron oxide thin films as humidity-sensitive materials for humidity sensors. In addition, the possibility of a humidity sensor with a wide dynamic range was investigated by evaluating the relationship between the film thickness of the iron oxide thin film, the electrode width of the device, and the humidity-sensitive characteristics. As a result, it was found that the crystal structure of α-Fe2O3 exhibits relatively good humidity sensitivity compared to other crystal structures, and that the sensitivity to humidity can be adjusted by appropriately selecting the electrode width and film thickness of the device. Therefore, the α-Fe2O3 thin film may be useful as a moisture-sensitive material for wide dynamic range humidity sensors by appropriately adjusting the film thickness and electrode width.

This study aimed to develop teaching materials for circuit design and fabrication for elementary school students, and conduct workshops oriented to engineering. First, the content of the circuit design workshop was discussed and it was determined that a connection-focused design would be appropriate. Second, we examined the issue of existing teaching materials. Many of the existing kit materials were not suitable for learning circuit design as it was already completed. In addition, many of them required soldering work, which was too difficult for elementary school students. Hands-on materials that allow students to construct circuits through trial and error were suitable for learning circuit design. Therefore, we developed design and fabrication support materials using a 3D printer and conductive tape. Next, we provided workshop opportunities using developed material, with the theme of “making light-up cards,” wherein elementary school students worked on designing the layout of the components and fabrication. Consequently, students’ conceptual understanding of the connection was improved. All students were able to complete the circuit, with high self-evaluations of satisfaction and understanding suggesting that the activity was engineering-oriented.

In recent years, with the development of IoT, research and development of wireless sensor networks for monitoring has been advanced to monitor the condition of various devices in railway vehicles and notify train crews. In the operation of railway vehicles, the composition may be changed at stations by coupling and decoupling, and it is necessary to set up inter-vehicle wireless network considering them. Therefore, to transmit sensor data in railway vehicles, we propose an autonomous configuration establishment method of wireless network for railway vehicles considering coupling and decoupling.