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Volume 51, Issue 10
Displaying 1-10 of 10 articles from this issue
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Special Issue on Sensing Technologies for Supporting Humans, Environment and Society
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[in Japanese], [in Japanese], [in Japanese], [in Japanese], [in Japane ...2015 Volume 51 Issue 10 Pages 667
Published: 2015
Released on J-STAGE: October 23, 2015
JOURNAL FREE ACCESSDownload PDF (227K)
Paper
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Kazunori ODANI, Yusuke HIGUCHI, Masahiro ITO, Takaaki NARA, Shigeru AN ...2015 Volume 51 Issue 10 Pages 668-677
Published: 2015
Released on J-STAGE: October 23, 2015
JOURNAL FREE ACCESSIn this paper, we propose a novel method for estimating the position and posture of a smartphone which has a magnetic dipole inside a speaker by using the weighted integral method with a linear magnetic sensor. We derive a system of linear equations relating the dipole position and the weighted integrals of the magnetic flux density on the linear sensor. We prove that, although the coefficient matrix for a single linear sensor is possible to be singular, use of two linear sensors that do not exist on the same plane enables us to uniquely localize the dipole. Based on the simulations, we develop a non-coplanar, cruciform array of magnetic impedance sensors. We demonstrate that the method is applicable to position and posture estimation of a neodymium magnet and a smartphone.View full abstractDownload PDF (1515K) -
Hiroto YOSHINARI, Kosuke TSUKAMOTO2015 Volume 51 Issue 10 Pages 678-686
Published: 2015
Released on J-STAGE: October 23, 2015
JOURNAL FREE ACCESSDelta-sigma (ΔΣ) analog-to-digital converters (ADC's) have been used for the application area that requires high-resolution signal acquisition. Most of the ΔΣ ADC's use the low-pass type ΔΣ modulators, where it is necessary to prepare a sufficiently high sampling frequency than the input signal. On the other hand, it is useful to convert only a specific band signal with a high accuracy in sensing systems and voice-band telecommunications. In order to satisfy the demands, band-pass ΔΣ modulators have been proposed. Band-pass ΔΣ modulators, as opposed to the low-pass type modulators, are able to convert signals that have closer sampling frequencies. In addition, the band-pass ΔΣ modulators suppress the low-frequency noise. In general, however, the center frequency and sampling frequency of a band-pass modulator is determined at the design stage. Therefore, it is difficult to apply bandwidths that are different from the original intended design. This paper proposes a band-pass ΔΣ modulator with variable center frequency. The modulator is designed by using multistage structure, thereby the modulator's stability and accuracy has improved. Furthermore, a self-calibration method for noise leakage due to a mismatch between the analog loop filter and the back-end digital filter are also proposed. The modulator with proposed methods was investigated using MATLAB simulator, confirming the effectiveness of the band-pass ΔΣ modulator.View full abstractDownload PDF (1243K) -
Satoshi TSUJI, Teruhiko KOHAMA2015 Volume 51 Issue 10 Pages 687-695
Published: 2015
Released on J-STAGE: October 23, 2015
JOURNAL FREE ACCESSWe developed a layered 3D touch screen using mutual capacitance measurement to detect an object both before and after contact for operation of a 3D image on the display. The 3D touch screen can detect indentations and the precise position of an object and can identify the material in contact. In addition, it can detect the object and its position during non-contact (proximity range). In this paper, the proposed 3D touch screen is measured the precise X-Y position of the object at proximity range. In addition, the 3D touch screen is detected the distance between the 3D touch screen and object. The 3D touch screen may be used as functional and useful interface.View full abstractDownload PDF (1987K) -
Nobuhiro SHIMOI, Carlos CUADRA, Takuya SASAKI, Hirokazu MADOKORO, Masa ...2015 Volume 51 Issue 10 Pages 696-705
Published: 2015
Released on J-STAGE: October 23, 2015
JOURNAL FREE ACCESSApplicability of new piezoelectric limit sensor to detect premonitory failure during static loading test is discussed in this paper. For that purpose, brick masonry specimens were subjected to compression test to evaluate their mechanical properties and to investigate proposed sensor response. These new sensors consist of a glass pipe containing piezoelectric film elements for measurement of signals during static loading test. The glass pipe can be directly installed in brick masonry specimens or it can be inserted into holder. In this research tube holder was made of brass material. Examination for glass pipe alone and glass pipe with brass holder are discussed in this report. And for comparison, results of measurements with piezoelectric vibration sensor are presented. Results show that sensors respond before and during broken of brick masonry specimens. Responses before broken of brick masonry specimen can be used as forecast signals to indicate dangerous condition of the structure. In case of actual buildings, these forecast signals can be employed for collapse prevention and damages mitigation. These sensors can be also used for real time structural health monitoring to detect limit state of damage or collapse.View full abstractDownload PDF (3471K) -
Yuta MOTOYASU, Yuji GOTOH2015 Volume 51 Issue 10 Pages 706-712
Published: 2015
Released on J-STAGE: October 23, 2015
JOURNAL FREE ACCESSThe mutual induction type eddy current testing using a spiral type search coil is one of the eddy current testing (ECT). In this type ECT probe, since the thickness of a spiral search coil is very thin, the distance (lift-off: Lo) between the ECT probe and the specimen is able to set small. Therefore, the high detection sensitivity is obtained. However, since the wire is coiled in the shape of spiral, the evaluation of the flux density inside the spiral search coil is made difficult by experiment. Moreover, the phenomenon elucidation of inspection using this ECT probe is not carried out. In this paper, the inspection characteristic of a surface defect on an aluminum plate using this probe was investigated by 3-D alternating electromagnetic finite element method (FEM). Moreover, the evaluation in consideration of the characteristic of the spiral search coil in this ECT probe is also investigated by 3D FEM and experimental verification.View full abstractDownload PDF (1728K) -
Takanori FUJII, Hiroyuki KOMORI, Yuji GOTOH, Yoshitaka MIYAZAKI2015 Volume 51 Issue 10 Pages 713-723
Published: 2015
Released on J-STAGE: October 23, 2015
JOURNAL FREE ACCESSAbout 10% of stroke patients have a swallowing difficulty. In these circumstances, the nutrition is poured into the stomach using a nasogastric tube made of resin. When the tube is inserted from a nostril to the stomach, it may be inserted into the lungs by mistake. It will become a fatal situation if the nutrition is fed incorrectly. In this paper, the inspection technique of the position of the tip of the tube by detecting the alternating magnetic field excited from ten positions on the human body using a 3-axis search coil at the tip of the tube. It is shown that the maximum error of positioning is less than 10mm, so that the proposed technique can be safely applicable in medical practice.View full abstractDownload PDF (4633K) -
Takashi MATSUZAKI, Kousuke MARUYAMA, Yasushi OBATA, Kentaro SAKISAKA, ...2015 Volume 51 Issue 10 Pages 724-735
Published: 2015
Released on J-STAGE: October 23, 2015
JOURNAL FREE ACCESSDistributed sensor data fusion (DSDF) which generates integrated track from the data of networked and distributed sensors, achieve high track accuracy. One of the issues of DSDF is to achieve both track accuracy and low traffic simultaneously. However, conventional DSDF oversupplies sensor data to network. Therefore we propose new DSDF with transmit assignment. We confirm that the effectiveness to proposed method in view of network traffic and tracking accuracy through computer simulation.View full abstractDownload PDF (1639K)
Paper
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Hideo MUROI, Yu TAKESHITA, Shuichi ADACHI2015 Volume 51 Issue 10 Pages 736-743
Published: 2015
Released on J-STAGE: October 23, 2015
JOURNAL FREE ACCESSFit ratio is one of the most popular criteria that evaluates a result of system identification in the time domain. This criterion is constructed by Root Mean Squared Error (RMSE) divided by the standard deviation of the measured signal. However the validity of fit ratio have not been discussed actively in the field of system identification. In this paper, we introduce some discussion about criteria like fit ratio from the field of physical geography. Then, we evaluated these criteria through two case studies. As a result, we found that fit ratio was not adequate for evaluation of the result of system identification.View full abstractDownload PDF (695K) -
Yoichi MASUDA, Kenji NAGASE2015 Volume 51 Issue 10 Pages 744-754
Published: 2015
Released on J-STAGE: October 23, 2015
JOURNAL FREE ACCESSThis paper proposes a cooperative formation control of multi-agent systems by using self-equilibrium condition based on the force-density method. The force-density method is widely used in structural mechanics, which enables us to design the equilibrium of axially loaded structures (tensegrity structures) with non-zero control force. The control law is derived from a potential function of linear springs connecting the agents. Replacing the design variables in linear springs by force density (control force per unit length) and member constant (product of spring constant and rest length), the design problems can be described as convex optimization problems. As an application of the proposed strategy, a control design method for multi-agent systems with communication time-delays is provided. Permissible time-delay is maximized by minimizing the maximum eigen value of the tangent rigidity matrix. Numerical examples show that the permissible time-delay is increased by introducing the non-zero internal force.View full abstractDownload PDF (1974K)
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