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Open AccessEditorial

Introduction to the Special Issue on “State-of-the-Art Sensor Technology in Japan 2015”

by Masahiro Tokumitsu and Yoshiteru Ishida

Sensors 2016, 16(9), 1350; https://doi.org/10.3390/s16091350 - 23 Aug 2016

Viewed by 4350

Abstract

This Special Issue, “State-of-the-Art Sensor Technology in Japan 2015”, collected papers on different kinds of sensing technology: fundamental technology for intelligent sensors, information processing for monitoring humans, and information processing for adaptive and survivable sensor systems.[...] Full article

(This article belongs to the Special Issue State-of-the-Art Sensors Technology in Japan 2015)

Research

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1073 KiB

Open AccessArticle

Resilient Sensor Networks with Spatiotemporal Interpolation of Missing Sensors: An Example of Space Weather Forecasting by Multiple Satellites

by Masahiro Tokumitsu, Keisuke Hasegawa and Yoshiteru Ishida

Sensors 2016, 16(4), 548; https://doi.org/10.3390/s16040548 - 15 Apr 2016

Cited by 3 | Viewed by 4811

Abstract

This paper attempts to construct a resilient sensor network model with an example of space weather forecasting. The proposed model is based on a dynamic relational network. Space weather forecasting is vital for a satellite operation because an operational team needs to make [...] Read more.

This paper attempts to construct a resilient sensor network model with an example of space weather forecasting. The proposed model is based on a dynamic relational network. Space weather forecasting is vital for a satellite operation because an operational team needs to make a decision for providing its satellite service. The proposed model is resilient to failures of sensors or missing data due to the satellite operation. In the proposed model, the missing data of a sensor is interpolated by other sensors associated. This paper demonstrates two examples of space weather forecasting that involves the missing observations in some test cases. In these examples, the sensor network for space weather forecasting continues a diagnosis by replacing faulted sensors with virtual ones. The demonstrations showed that the proposed model is resilient against sensor failures due to suspension of hardware failures or technical reasons. Full article

(This article belongs to the Special Issue State-of-the-Art Sensors Technology in Japan 2015)

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828 KiB

Open AccessArticle

Quantitative Evaluation System of Soft Neurological Signs for Children with Attention Deficit Hyperactivity Disorder

by Miki Kaneko, Yushiro Yamashita and Keiji Iramina

Sensors 2016, 16(1), 116; https://doi.org/10.3390/s16010116 - 18 Jan 2016

Cited by 6 | Viewed by 6913

Abstract

Attention deficit hyperactivity disorder (ADHD) is a neurodevelopmental disorder characterized by symptoms of inattention, hyperactivity, and impulsivity. Soft neurological signs (SNS) are minor neurological abnormalities in motor performance, and are used as one evaluation method for neurodevelopmental delays in children with ADHD. Our [...] Read more.

Attention deficit hyperactivity disorder (ADHD) is a neurodevelopmental disorder characterized by symptoms of inattention, hyperactivity, and impulsivity. Soft neurological signs (SNS) are minor neurological abnormalities in motor performance, and are used as one evaluation method for neurodevelopmental delays in children with ADHD. Our aim is to establish a quantitative evaluation system for children with ADHD. We focused on the arm movement called pronation and supination, which is one such soft neurological sign. Thirty three children with ADHD aged 7–11 years (27 males, six females) and twenty five adults participants aged 21–29 years old (19 males, six females) participated in our experiments. Our results suggested that the pronation and supination function in children with ADHD has a tendency to lag behind that of typically developing children by several years. From these results, our system has a possibility to objectively evaluate the neurodevelopmental delay of children with ADHD. Full article

(This article belongs to the Special Issue State-of-the-Art Sensors Technology in Japan 2015)

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2832 KiB

Open AccessArticle

Soft Neurological Signs in Childhood by Measurement of Arm Movements Using Acceleration and Angular Velocity Sensors

by Miki Kaneko, Yushiro Yamashita, Osamu Inomoto and Keiji Iramina

Sensors 2015, 15(10), 25793-25808; https://doi.org/10.3390/s151025793 - 12 Oct 2015

Cited by 5 | Viewed by 5967

Abstract

Soft neurological signs (SNS) are evident in the motor performance of children and disappear as the child grows up. Therefore SNS are used as criteria for evaluating age-appropriate development of neurological function. The aim of this study was to quantify SNS during arm [...] Read more.

Soft neurological signs (SNS) are evident in the motor performance of children and disappear as the child grows up. Therefore SNS are used as criteria for evaluating age-appropriate development of neurological function. The aim of this study was to quantify SNS during arm movement in childhood. In this study, we focused on pronation and supination, which are arm movements included in the SNS examination. Two hundred and twenty-three typically developing children aged 4–12 years (107 boys, 116 girls) and 18 adults aged 21–26 years (16 males, two females) participated in the experiment. To quantify SNS during pronation and supination, we calculated several evaluation index scores: bimanual symmetry, compliance, postural stability, motor speed and mirror movement. These index scores were evaluated using data obtained from sensors attached to the participants’ hands and elbows. Each score increased as age increased. Results obtained using our system showed developmental changes that were consistent with criteria for SNS. We were able to successfully quantify SNS during pronation and supination. These results indicate that it may be possible to use our system as quantitative criteria for evaluating development of neurological function. Full article

(This article belongs to the Special Issue State-of-the-Art Sensors Technology in Japan 2015)

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545 KiB

Open AccessArticle

Monitoring of Weekly Sleep Pattern Variations at Home with a Contactless Biomotion Sensor

by Masanori Hashizaki, Hiroshi Nakajima and Kazuhiko Kume

Sensors 2015, 15(8), 18950-18964; https://doi.org/10.3390/s150818950 - 3 Aug 2015

Cited by 31 | Viewed by 5914

Abstract

Many people find that their sleep is restricted or disturbed by social obligations, including work. Sleep phase delays can affect an individual’s circadian rhythms on the following day and cause daytime sleepiness and/or poor performance. In this study, to examine weekly variations in [...] Read more.

Many people find that their sleep is restricted or disturbed by social obligations, including work. Sleep phase delays can affect an individual’s circadian rhythms on the following day and cause daytime sleepiness and/or poor performance. In this study, to examine weekly variations in sleep patterns, we analyzed sleep data for seven-day periods (from Sunday to Saturday) that had been collected from 2914 subjects (aged 20–79 years) over a total of 24,899 subject-weeks using contactless biomotion sensors. On the weekend, the subjects’ mean sleep midpoint, bedtime, and wake-up time were delayed by 40, 26 and 53 min, respectively, compared with those seen on weekdays. In addition, on weekdays, the mean difference between the maximum and median sleep midpoint ranged from 35 to 47 min among the subjects in their 20 s–70 s. The weekend delay and weekday variation in the subjects’ sleep patterns tended to decrease with age. This study detected sleep pattern disturbances on both weekdays and weekends. The serial changes in weekday bedtimes detected in this study suggest that sleep habits are influenced by changes in the temporal patterns of social activities/duties. We need further study the advantages of getting extra sleep and the disadvantages of sleep pattern disturbances in daily lifestyle. Full article

(This article belongs to the Special Issue State-of-the-Art Sensors Technology in Japan 2015)

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1488 KiB

Open AccessArticle

Phase Difference Optimization of Dual-Wavelength Excitation for the CW-Photoacoustic-Based Noninvasive and Selective Investigation of Aqueous Solutions of Glucose

by Serge Camou

Sensors 2015, 15(7), 16358-16371; https://doi.org/10.3390/s150716358 - 7 Jul 2015

Cited by 3 | Viewed by 5582

Abstract

Towards the noninvasive and continuous monitoring of blood glucose levels, we chose the continuous-wave photoacoustic (CW-PA) technique and developed the optical power balance shift (OPBS) method. However, operating with optical wavelengths in the near-infrared (NIR) region ensures deep penetration inside human soft-tissue, but [...] Read more.

Towards the noninvasive and continuous monitoring of blood glucose levels, we chose the continuous-wave photoacoustic (CW-PA) technique and developed the optical power balance shift (OPBS) method. However, operating with optical wavelengths in the near-infrared (NIR) region ensures deep penetration inside human soft-tissue, but also leads to two serious issues: strong background level noise from water molecules in this wavelength range and small differences between the absorbance spectra of diluted compounds. To resolve them, the OPBS method relies on simultaneous optical excitation at two wavelengths for differential measurements. However, the first validation in vitro with calibrated aqueous solutions of glucose and albumin revealed strong dependence on the phase difference between the two lights sources. In this paper, we report a systematic investigation of this parameter, from PA-based measurements over a wide range of phase differences and an extensive characterization in the frequency domain. The process of maintaining the phase quadrature of the two optical signals is demonstrated in real time through an analysis of the PA signal and therefore does not require any additional equipment. Finally, a comparison of aqueous glucose solution characterizations at high concentration levels with the two methods was performed and consistent results were obtained. Full article

(This article belongs to the Special Issue State-of-the-Art Sensors Technology in Japan 2015)

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1408 KiB

Open AccessArticle

Detection Wavelength Control of Uncooled Infrared Sensors Using Two-Dimensional Lattice Plasmonic Absorbers

by Yousuke Takagawa, Shinpei Ogawa and Masafumi Kimata

Sensors 2015, 15(6), 13660-13669; https://doi.org/10.3390/s150613660 - 10 Jun 2015

Cited by 31 | Viewed by 6776

Abstract

Wavelength-selective uncooled infrared (IR) sensors are highly promising for a wide range of applications, such as fire detection, gas analysis and biomedical analysis. We have recently developed wavelength-selective uncooled IR sensors using square lattice two-dimensional plasmonic absorbers (2-D PLAs). The PLAs consist of [...] Read more.

Wavelength-selective uncooled infrared (IR) sensors are highly promising for a wide range of applications, such as fire detection, gas analysis and biomedical analysis. We have recently developed wavelength-selective uncooled IR sensors using square lattice two-dimensional plasmonic absorbers (2-D PLAs). The PLAs consist of a periodic 2-D lattice of Au-based dimples, which allow photons to be manipulated using surface plasmon modes. In the present study, a detailed investigation into control of the detection wavelength was conducted by varying the PLA lattice structure. A comparison was made between wavelength-selective uncooled IR sensors with triangular and square PLA lattices that were fabricated using complementary metal oxide semiconductor and micromachining techniques. Selective enhancement of the responsivity could be achieved, and the detection wavelength for the triangular lattice was shorter than that for the square lattice. The results indicate that the detection wavelength is determined by the reciprocal-lattice vector for the PLAs. The ability to control the detection wavelength in this manner enables the application of such PLAs to many types of thermal IR sensors. The results obtained here represent an important step towards multi-color imaging in the IR region. Full article

(This article belongs to the Special Issue State-of-the-Art Sensors Technology in Japan 2015)

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1695 KiB

Open AccessArticle

Ratiometric Molecular Probes Based on Dual Emission of a Blue Fluorescent Coumarin and a Red Phosphorescent Cationic Iridium(III) Complex for Intracellular Oxygen Sensing

by Toshitada Yoshihara, Saori Murayama and Seiji Tobita

Sensors 2015, 15(6), 13503-13521; https://doi.org/10.3390/s150613503 - 9 Jun 2015

Cited by 48 | Viewed by 8474

Abstract

Ratiometric molecular probes RP1 and RP2 consisting of a blue fluorescent coumarin and a red phosphorescent cationic iridium complex connected by a tetra- or octaproline linker, respectively, were designed and synthesized for sensing oxygen levels in living cells. These probes exhibited dual emission [...] Read more.

Ratiometric molecular probes RP1 and RP2 consisting of a blue fluorescent coumarin and a red phosphorescent cationic iridium complex connected by a tetra- or octaproline linker, respectively, were designed and synthesized for sensing oxygen levels in living cells. These probes exhibited dual emission with good spectral separation in acetonitrile. The photorelaxation processes, including intramolecular energy transfer, were revealed by emission quantum yield and lifetime measurements. The ratios (R_I = (I_p /I_f) ) between the phosphorescence (I_p) and fluorescence (I_f) intensities showed excellent oxygen responses; the ratio of R_I under degassed and aerated conditions (

R_{I}^{0}

/ R_I) was 20.3 and 19.6 for RP1 and RP2. The introduction of the cationic Ir (III) complex improved the cellular uptake efficiency compared to that of a neutral analogue with a tetraproline linker. The emission spectra of the ratiometric probes internalized into living HeLa or MCF-7 cells could be obtained using a conventional microplate reader. The complex RP2 with an octaproline linker provided ratios comparable to the ratiometric measurements obtained using a microplate reader: the ratio of the value of RP2 under hypoxia (2.5% O₂) to that under normoxia (21% O₂) was 1.5 and 1.7 for HeLa and MCF-7 cells, respectively. Thus, the intracellular oxygen levels of MCF-7 cells could be imaged by ratiometric emission measurements using the complex RP2. Full article

(This article belongs to the Special Issue State-of-the-Art Sensors Technology in Japan 2015)

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1002 KiB

Open AccessArticle

Multiple Human Tracking Using Binary Infrared Sensors

by Toshiaki Miyazaki and Yuki Kasama

Sensors 2015, 15(6), 13459-13476; https://doi.org/10.3390/s150613459 - 8 Jun 2015

Cited by 22 | Viewed by 6166

Abstract

To create a context-aware environment, human locations and movement paths must be considered. In this paper, we propose an algorithm that tracks human movement paths using only binary sensed data obtained by infrared (IR) sensors attached to the ceiling of a room. Our [...] Read more.

To create a context-aware environment, human locations and movement paths must be considered. In this paper, we propose an algorithm that tracks human movement paths using only binary sensed data obtained by infrared (IR) sensors attached to the ceiling of a room. Our algorithm can estimate multiple human movement paths without a priori knowledge of the number of humans in the room. By repeating predictions and estimations of human positions and links from the previous human positions to the estimated ones at each time period, human movement paths can be estimated. Simulation-based evaluation results show that our algorithm can dynamically trace human movement paths. Full article

(This article belongs to the Special Issue State-of-the-Art Sensors Technology in Japan 2015)

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1898 KiB

Open AccessArticle

Gated Silicon Drift Detector Fabricated from a Low-Cost Silicon Wafer

by Hideharu Matsuura, Shungo Sakurai, Yuya Oda, Shinya Fukushima, Shohei Ishikawa, Akinobu Takeshita and Atsuki Hidaka

Sensors 2015, 15(5), 12022-12033; https://doi.org/10.3390/s150512022 - 22 May 2015

Cited by 4 | Viewed by 7227

Abstract

Inexpensive high-resolution silicon (Si) X-ray detectors are required for on-site surveys of traces of hazardous elements in food and soil by measuring the energies and counts of X-ray fluorescence photons radially emitted from these elements. Gated silicon drift detectors (GSDDs) are much cheaper [...] Read more.

Inexpensive high-resolution silicon (Si) X-ray detectors are required for on-site surveys of traces of hazardous elements in food and soil by measuring the energies and counts of X-ray fluorescence photons radially emitted from these elements. Gated silicon drift detectors (GSDDs) are much cheaper to fabricate than commercial silicon drift detectors (SDDs). However, previous GSDDs were fabricated from \(10\)-k\(\Omega \cdot\)cm Si wafers, which are more expensive than \(2\)-k\(\Omega \cdot\)cm Si wafers used in commercial SDDs. To fabricate cheaper portable X-ray fluorescence instruments, we investigate GSDDs formed from \(2\)-k\(\Omega \cdot\)cm Si wafers. The thicknesses of commercial SDDs are up to \(0.5\) mm, which can detect photons with energies up to \(27\) keV, whereas we describe GSDDs that can detect photons with energies of up to \(35\) keV. We simulate the electric potential distributions in GSDDs with Si thicknesses of \(0.5\) and \(1\) mm at a single high reverse bias. GSDDs with one gate pattern using any resistivity Si wafer can work well for changing the reverse bias that is inversely proportional to the resistivity of the Si wafer. Full article

(This article belongs to the Special Issue State-of-the-Art Sensors Technology in Japan 2015)

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1387 KiB

Open AccessArticle

Study of the Relationship between Taste Sensor Response and the Amount of Epigallocatechin Gallate Adsorbed Onto a Lipid-Polymer Membrane

by Yuhei Harada, Yusuke Tahara and Kiyoshi Toko

Sensors 2015, 15(3), 6241-6249; https://doi.org/10.3390/s150306241 - 13 Mar 2015

Cited by 15 | Viewed by 6999

Abstract

A taste sensor using lipid-polymer membranes has been developed to evaluate the taste of foods, beverages and medicines. The response of the taste sensor, measured as a change in the membrane potential caused by adsorption (CPA), corresponds to the aftertaste felt by humans. [...] Read more.

A taste sensor using lipid-polymer membranes has been developed to evaluate the taste of foods, beverages and medicines. The response of the taste sensor, measured as a change in the membrane potential caused by adsorption (CPA), corresponds to the aftertaste felt by humans. The relationships between the CPA value and the amount of adsorbed taste substances, quinine and iso-α acid (bitterness), and tannic acid (astringency), have been studied so far. However, that of epigallocatechin gallate (EGCg) has not been clarified, although EGCg is abundantly present in green tea as one of its astringent substances. This study aimed at clarifying the response of the taste sensor to EGCg and its relationship with the amount of EGCg adsorbed onto lipid-polymer membranes. The lipid concentration dependence of the CPA value was similar to that of the amount of adsorbed EGCg, indicating a high correlation between the CPA value and the amount of adsorbed EGCg. The CPA value increased with increasing amount of adsorbed EGCg; however, the CPA value showed a tendency of leveling off when the amount of adsorbed EGCg further increased. Full article

(This article belongs to the Special Issue State-of-the-Art Sensors Technology in Japan 2015)

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Review

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Fiber-Optic Chemical Sensors and Fiber-Optic Bio-Sensors

by Marie Pospíšilová, Gabriela Kuncová and Josef Trögl

Sensors 2015, 15(10), 25208-25259; https://doi.org/10.3390/s151025208 - 30 Sep 2015

Cited by 156 | Viewed by 19681

Abstract

This review summarizes principles and current stage of development of fiber-optic chemical sensors (FOCS) and biosensors (FOBS). Fiber optic sensor (FOS) systems use the ability of optical fibers (OF) to guide the light in the spectral range from ultraviolet (UV) (180 nm) up [...] Read more.

This review summarizes principles and current stage of development of fiber-optic chemical sensors (FOCS) and biosensors (FOBS). Fiber optic sensor (FOS) systems use the ability of optical fibers (OF) to guide the light in the spectral range from ultraviolet (UV) (180 nm) up to middle infrared (IR) (10 μm) and modulation of guided light by the parameters of the surrounding environment of the OF core. The introduction of OF in the sensor systems has brought advantages such as measurement in flammable and explosive environments, immunity to electrical noises, miniaturization, geometrical flexibility, measurement of small sample volumes, remote sensing in inaccessible sites or harsh environments and multi-sensing. The review comprises briefly the theory of OF elaborated for sensors, techniques of fabrications and analytical results reached with fiber-optic chemical and biological sensors. Full article

(This article belongs to the Special Issue State-of-the-Art Sensors Technology in Japan 2015)

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