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Sensors, Volume 8, Issue 12 (December 2008) , Pages 7564-8491

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Open AccessArticle
Estimation of Atmospheric Path Delays in TerraSAR-X Data using Models vs. Measurements
Sensors 2008, 8(12), 8479-8491; https://doi.org/10.3390/s8128479
Received: 11 November 2008 / Revised: 11 December 2008 / Accepted: 12 December 2008 / Published: 19 December 2008
Cited by 35 | Viewed by 8299 | PDF Full-text (786 KB) | HTML Full-text | XML Full-text
Abstract
Spaceborne synthetic aperture radar (SAR) measurements of the Earth’s surface depend on electromagnetic waves that are subject to atmospheric path delays, in turn affecting geolocation accuracy. The atmosphere influences radar signal propagation by modifying its velocity and direction, effects which can be modeled. [...] Read more.
Spaceborne synthetic aperture radar (SAR) measurements of the Earth’s surface depend on electromagnetic waves that are subject to atmospheric path delays, in turn affecting geolocation accuracy. The atmosphere influences radar signal propagation by modifying its velocity and direction, effects which can be modeled. We use TerraSAR-X (TSX) data to investigate improvements in the knowledge of the scene geometry. To precisely estimate atmospheric path delays, we analyse the signal return of four corner reflectors with accurately surveyed positions (based on differential GPS), placed at different altitudes yet with nearly identical slant ranges to the sensor. The comparison of multiple measurements with path delay models under these geometric conditions also makes it possible to evaluate the corrections for the atmospheric path delay made by the TerraSAR processor and to propose possible improvements. Full article
(This article belongs to the Section Remote Sensors, Control, and Telemetry)
Open AccessArticle
Voltammetric Behaviour of Sulfamethoxazole on Electropolymerized-Molecularly Imprinted Overoxidized Polypyrrole
Sensors 2008, 8(12), 8463-8478; https://doi.org/10.3390/s8128463
Received: 19 November 2008 / Revised: 7 December 2008 / Accepted: 18 December 2008 / Published: 18 December 2008
Cited by 73 | Viewed by 5729 | PDF Full-text (234 KB) | HTML Full-text | XML Full-text
Abstract
In this work, preparation of a molecularly imprinted polymer (MIP) film and its recognition properties for sulfamethoxazolewere investigated. The overoxidized polypyrrole (OPPy) film was prepared by the cyclic voltammetric deposition of pyrrole (Py) in the presence of supporting electrolyte (tetrabutylammonium perchlorate-TBAP) with and [...] Read more.
In this work, preparation of a molecularly imprinted polymer (MIP) film and its recognition properties for sulfamethoxazolewere investigated. The overoxidized polypyrrole (OPPy) film was prepared by the cyclic voltammetric deposition of pyrrole (Py) in the presence of supporting electrolyte (tetrabutylammonium perchlorate-TBAP) with and without a template molecule (sulfamethoxazole) on a pencil graphite electrode (PGE). The voltammetric behaviour of sulfamethoxazole on imprinted and non-imprinted (NIP) films was investigated by differential pulse voltammetry (DPV) in Britton-Robinson (BR) buffer solutions prepared in different ratio of acetonitrile-water binary mixture, between the pH 1.5 and 7.0. The effect of the acetonitrile-water ratio and pH, monomer and template concentrations, electropolymerization cycles on the performance of the MIP electrode was investigated and optimized. The MIP electrode exhibited the best reproducibility and highest sensitivity. The results showed that changing acetonitrile-water ratio and pH of BR buffer solution changes the oxidation peak current values. The highest anodic signal of sulfamethoxazole was obtained in BR buffer solution prepared in 50% (v/v) acetonitrile-water at pH 2.5. The calibration curve for sulfamethoxazole at MIP electrode has linear region for a concentration range of 25.10-3 to 0.75 mM (R2=0.9993). The detection limit of sulfamethoxazole was found as 3.59.10-4 mM (S/N=3). The same method was also applied to determination of sulfamethoxazole in commercial pharmaceutical samples. Method precision (RSD<1%) and recoveries (>87%) were satisfactory. The proposed method is simple and quick. The polypyrrole (PPy) electrodes have low response time, good mechanical stability and are disposable simple to construct. Full article
(This article belongs to the Section Biosensors)
Open AccessCommunication
Conformational Mobility of GOx Coenzyme Complex on Single-Wall Carbon Nanotubes
Sensors 2008, 8(12), 8453-8462; https://doi.org/10.3390/s8128453
Received: 3 September 2008 / Revised: 30 November 2008 / Accepted: 4 December 2008 / Published: 18 December 2008
Cited by 14 | Viewed by 7360 | PDF Full-text (349 KB) | HTML Full-text | XML Full-text
Abstract
A critical issue in bioelectrochemical applications that use electrodes modified by Single Wall Carbon Nanotubes (SWCNTs) is to ensure high activity of the catalytic site of an immobilized enzyme protein interacting with nanomaterials. Since Flavin Adenine Dinucleotide (FAD), a coenzyme of glucose oxidase [...] Read more.
A critical issue in bioelectrochemical applications that use electrodes modified by Single Wall Carbon Nanotubes (SWCNTs) is to ensure high activity of the catalytic site of an immobilized enzyme protein interacting with nanomaterials. Since Flavin Adenine Dinucleotide (FAD), a coenzyme of glucose oxidase (GOx), is the active center of the catalytic site, conformation of which could determine the activity of enzyme, it is important to understand the dynamic mechanism of its conformational mobility while GOx is adsorbed on SWCNTs with multiple orientations. However, this dynamic mechanism still remains unclear at the atomic level due to the coenzyme being embedded in the apo-GOx and the limitations of appropriate experimental methods. In this study, a molecular dynamics (MD) simulation was performed to investigate the conformational mobility mechanism of the coenzyme. The trajectory and the interaction energy clearly indicate that the adsorption of GOx onto SWCNTs plays an important role in the conformational mobility of the coenzyme, and its mobility is greatly affected by the distribution of water molecules due to it being hydrophobic. Full article
(This article belongs to the Section Chemical Sensors)
Open AccessReview
A Nonoxidative Electrochemical Sensor Based on a Self-Doped Polyaniline/Carbon Nanotube Composite for Sensitive and Selective Detection of the Neurotransmitter Dopamine: A Review
Sensors 2008, 8(12), 8423-8452; https://doi.org/10.3390/s8128423
Received: 29 July 2008 / Revised: 12 December 2008 / Accepted: 16 December 2008 / Published: 18 December 2008
Cited by 49 | Viewed by 11296 | PDF Full-text (1821 KB) | HTML Full-text | XML Full-text
Abstract
Most of the current techniques for in vivo detection of dopamine exploit the ease of oxidation of this compound. The major problem during the detection is the presence of a high concentration of ascorbic acid that is oxidized at nearly the same potential [...] Read more.
Most of the current techniques for in vivo detection of dopamine exploit the ease of oxidation of this compound. The major problem during the detection is the presence of a high concentration of ascorbic acid that is oxidized at nearly the same potential as dopamine on bare electrodes. Furthermore, the oxidation product of dopamine reacts with ascorbic acid present in samples and regenerates dopamine again, which severely limits the accuracy of the detection. Meanwhile, the product could also form a melanin-like insulating film on the electrode surface, which decreases the sensitivity of the electrode. Various surface modifications on the electrode, new materials for making the electrodes, and new electrochemical techniques have been exploited to solve these problems. Recently we developed a new electrochemical detection method that did not rely on direct oxidation of dopamine on electrodes, which may naturally solve these problems. This approach takes advantage of the high performance of our newly developed poly(anilineboronic acid)/carbon nanotube composite and the excellent permselectivity of the ion-exchange polymer Nafion. The high affinity binding of dopamine to the boronic acid groups of the polymer affects the electrochemical properties of the polyaniline backbone, which act as the basis for the transduction mechanism of this non-oxidative dopamine sensor. The unique reduction capability and high conductivity of single-stranded DNA functionalized single-walled carbon nanotubes greatly improved the electrochemical activity of the polymer in a physiologically-relevant buffer, and the large surface area of the carbon nanotubes increased the density of the boronic acid receptors. The high sensitivity and selectivity of the sensor show excellent promise toward molecular diagnosis of Parkinson's disease. In this review, we will focus on the discussion of this novel detection approach, the new interferences in this detection approach, and how to eliminate these interferences toward in vivo and in vitro detection of the neurotransmitter dopamine. Full article
(This article belongs to the Special Issue Electrochemical Sensors Based on Conductive Polymers)
Open AccessArticle
Fully-Non-Contact Masking-Based Holography Inspection on Dimensionally Responsive Artwork Materials
Sensors 2008, 8(12), 8401-8422; https://doi.org/10.3390/s8128401
Received: 26 September 2008 / Revised: 8 December 2008 / Accepted: 18 December 2008 / Published: 18 December 2008
Cited by 12 | Viewed by 7928 | PDF Full-text (545 KB) | HTML Full-text | XML Full-text
Abstract
Environmental control in galleries and museums is a necessity and is informed by the knowledge of ongoing processes of deterioration which can threaten the integrity and stability of artworks. Invisible dimensional changes in many works of art occur following environmental fluctuations as materials [...] Read more.
Environmental control in galleries and museums is a necessity and is informed by the knowledge of ongoing processes of deterioration which can threaten the integrity and stability of artworks. Invisible dimensional changes in many works of art occur following environmental fluctuations as materials respond to the changes in humidity and temperature. The constant influence of dimensional changes usually remains invisible until displacement generates visible deterioration and irreversible damage. This paper exploits fully non contact coherent interferometry in a sequential masking procedure for visualising and studying surface deformation which is the direct effect of dimensional alterations induced by humidity changes. Surface deformation during dimensional displacements of constituent materials may occur on any artwork within an unstable environment. In this context, the presented research study explores the diagnostic potential of fully non contact sensors for the direct structural assessment of environmental effects as they occur in real time on works of art. The method is employed to characterise material responses, complementing and improving understanding of material behaviour in unstable environments. Full article
Open AccessReview
Nondestructive Characterization by Advanced Synchrotron Light Techniques: Spectromicroscopy and Coherent Radiology
Sensors 2008, 8(12), 8378-8400; https://doi.org/10.3390/s8128378
Received: 15 September 2008 / Revised: 3 December 2008 / Accepted: 11 December 2008 / Published: 16 December 2008
Cited by 2 | Viewed by 7142 | PDF Full-text (1371 KB) | HTML Full-text | XML Full-text
Abstract
The advanced characteristics of synchrotron light has led in recent years to the development of a series of new experimental techniques to investigate chemical and physical properties on a microscopic scale. Although originally developed for materials science and biomedical research, such techniques find [...] Read more.
The advanced characteristics of synchrotron light has led in recent years to the development of a series of new experimental techniques to investigate chemical and physical properties on a microscopic scale. Although originally developed for materials science and biomedical research, such techniques find increasing applications in other domains – and could be quite useful for the study and conservation of cultural heritage. Specifically, they can nondestructively provide detailed chemical composition information that can be useful for the identification of specimens, for the discovery of historical links based on the sources of chemical raw materials and on chemical processes, for the analysis of damage, their causes and remedies and for many other issues. Likewise, morphological and structural information on a microscopic scale is useful for the identification, study and preservation of many different cultural and historical specimens. We concentrate here on two classes of techniques: in the first case, photoemission spectromicroscopy. This is the result of the advanced evolution of photoemission techniques like ESCA (Electron Microscopy for Chemical Analysis). By combining high lateral resolution to spectroscopy, photoemission spectromicroscopy can deliver fine chemical information on a microscopic scale in a nondestructive fashion. The second class of techniques exploits the high lateral coherence of modern synchrotron sources, a byproduct of the quest for high brightness or brilliance. We will see that such techniques now push radiology into the submicron scale and the submillisecond time domain. Furthermore, they can be implemented in a tomographic mode, increasing the information and becoming potentially quite useful for the analysis of cultural heritage specimens. Full article
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Open AccessReview
Array Biosensor for Toxin Detection: Continued Advances
Sensors 2008, 8(12), 8361-8377; https://doi.org/10.3390/s8128361
Received: 31 October 2008 / Revised: 26 November 2008 / Accepted: 9 December 2008 / Published: 15 December 2008
Cited by 41 | Viewed by 7112 | PDF Full-text (413 KB) | HTML Full-text | XML Full-text
Abstract
The following review focuses on progress made in the last five years with the NRL Array Biosensor, a portable instrument for rapid and simultaneous detection of multiple targets. Since 2003, the Array Biosensor has been automated and miniaturized for operation at the point-of-use. [...] Read more.
The following review focuses on progress made in the last five years with the NRL Array Biosensor, a portable instrument for rapid and simultaneous detection of multiple targets. Since 2003, the Array Biosensor has been automated and miniaturized for operation at the point-of-use. The Array Biosensor has also been used to demonstrate (1) quantitative immunoassays against an expanded number of toxins and toxin indicators in food and clinical fluids, and (2) the efficacy of semi-selective molecules as alternative recognition moieties. Blind trials, with unknown samples in a variety of matrices, have demonstrated the versatility, sensitivity, and reliability of the automated system. Full article
(This article belongs to the Special Issue Toxin Sensors)
Open AccessReview
Na+,K+-ATPase as the Target Enzyme for Organic and Inorganic Compounds
Sensors 2008, 8(12), 8321-8360; https://doi.org/10.3390/s8128321
Received: 3 November 2008 / Revised: 9 November 2008 / Accepted: 11 December 2008 / Published: 15 December 2008
Cited by 19 | Viewed by 9584 | PDF Full-text (428 KB) | HTML Full-text | XML Full-text | Correction
Abstract
This paper gives an overview of the literature data concerning specific and non specific inhibitors of Na+,K+-ATPase receptor. The immobilization approaches developed to improve the rather low time and temperature stability of Na+,K+-ATPase, as well [...] Read more.
This paper gives an overview of the literature data concerning specific and non specific inhibitors of Na+,K+-ATPase receptor. The immobilization approaches developed to improve the rather low time and temperature stability of Na+,K+-ATPase, as well to preserve the enzyme properties were overviewed. The functional immobilization of Na+,K+-ATPase receptor as the target, with preservation of the full functional protein activity and access of various substances to an optimum number of binding sites under controlled conditions in the combination with high sensitive technology for the detection of enzyme activity is the basis for application of this enzyme in medical, pharmaceutical and environmental research. Full article
(This article belongs to the Special Issue Toxin Sensors)
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Open AccessReview
Imprinting of Molecular Recognition Sites on Nanostructures and Its Applications in Chemosensors
Sensors 2008, 8(12), 8291-8320; https://doi.org/10.3390/s8128291
Received: 7 November 2008 / Revised: 21 November 2008 / Accepted: 9 December 2008 / Published: 15 December 2008
Cited by 129 | Viewed by 9904 | PDF Full-text (1172 KB) | HTML Full-text | XML Full-text
Abstract
Biological receptors including enzymes, antibodies and active proteins have been widely used as the detection platform in a variety of chemo/biosensors and bioassays. However, the use of artificial host materials in chemical/biological detections has become increasingly attractive, because the synthetic recognition systems such [...] Read more.
Biological receptors including enzymes, antibodies and active proteins have been widely used as the detection platform in a variety of chemo/biosensors and bioassays. However, the use of artificial host materials in chemical/biological detections has become increasingly attractive, because the synthetic recognition systems such as molecularly imprinted polymers (MIPs) usually have lower costs, higher physical/chemical stability, easier preparation and better engineering possibility than biological receptors. Molecular imprinting is one of the most efficient strategies to offer a synthetic route to artificial recognition systems by a template polymerization technique, and has attracted considerable efforts due to its importance in separation, chemo/biosensors, catalysis and biomedicine. Despite the fact that MIPs have molecular recognition ability similar to that of biological receptors, traditional bulky MIP materials usually exhibit a low binding capacity and slow binding kinetics to the target species. Moreover, the MIP materials lack the signal-output response to analyte binding events when used as recognition elements in chemo/biosensors or bioassays. Recently, various explorations have demonstrated that molecular imprinting nanotechniques may provide a potential solution to these difficulties. Many successful examples of the development of MIP-based sensors have also been reported during the past several decades. This review will begin with a brief introduction to the principle of molecular imprinting nanotechnology, and then mainly summarize various synthesis methodologies and recognition properties of MIP nanomaterials and their applications in MIP-based chemosensors. Finally, the future perspectives and efforts in MIP nanomaterials and MIP-based sensors are given. Full article
(This article belongs to the Special Issue Molecular Recognition and Sensors, Including Molecular Imprinting)
Open AccessArticle
Comparison of a Resonant Mirror Biosensor (IAsys) and a Quartz Crystal Microbalance (QCM) for the Study on Interaction between Paeoniae Radix 801 and Endothelin-1
Sensors 2008, 8(12), 8275-8290; https://doi.org/10.3390/s8128275
Received: 17 September 2008 / Revised: 1 December 2008 / Accepted: 2 December 2008 / Published: 15 December 2008
Cited by 4 | Viewed by 7740 | PDF Full-text (244 KB) | HTML Full-text | XML Full-text
Abstract
A resonant mirror biosensor, IAsys, and a quartz crystal microbalance (QCM) are known independently as surface sensitive analytical devices capable of label-free and in situ bioassays. In this study, an IAsys and a QCM are employed for a new study on the action [...] Read more.
A resonant mirror biosensor, IAsys, and a quartz crystal microbalance (QCM) are known independently as surface sensitive analytical devices capable of label-free and in situ bioassays. In this study, an IAsys and a QCM are employed for a new study on the action mechanism of Paeoniae Radix 801 (P. radix 801) by detecting the specific interaction between P. radix 801 and endothelin-1 (ET-1). In the experiments, ET-1 was immobilized on the surfaces of the IAsys cuvette and the QCM substrate by surface modification techniques, and then P. radix 801 solution was contacted to the cuvette and the substrate, separately. Then, the binding and interaction process between P. radix 801 and ET-1 was monitored by IAsys and QCM, respectively. The experimental results showed that P. radix 801 binds ET-1 specifically. The IAsys and QCM response curves to the ET-1 immobilization and P. radix 801 binding are similar in reaction process, but different in binding profiles, reflecting different resonation principles. Although both IAsys and QCM could detect the interaction of P. radix 801 and ET-1 with high reproducibility and reliability through optimization of the ET-1 coating, the reproducibility and reliability obtained by IAsys are better than those obtained by QCM, since the QCM frequency is more sensitive to temperature fluctuations, atmospheric changes and mechanical disturbances. However, IAsys and QCM are generally potent and reliable tools to study the interaction of P. radix 801 and ET-1, and can conclusively be applied to the action mechanism of P. radix 801. Full article
(This article belongs to the Section Biosensors)
Open AccessArticle
Electrochemical Immunosensor Based on Polythionine/Gold Nanoparticles for the Determination of Aflatoxin B1
Sensors 2008, 8(12), 8262-8274; https://doi.org/10.3390/s8128262
Received: 19 September 2008 / Revised: 1 December 2008 / Accepted: 2 December 2008 / Published: 15 December 2008
Cited by 70 | Viewed by 8629 | PDF Full-text (702 KB) | HTML Full-text | XML Full-text
Abstract
An aflatoxin B1 (AFB1) electrochemical immunosensor was developed by the immobilisation of aflatoxin B1-bovine serum albumin (AFB1-BSA) conjugate on a polythionine (PTH)/gold nanoparticles (AuNP)-modified glassy carbon electrode (GCE). The surface of the AFB1-BSA conjugate [...] Read more.
An aflatoxin B1 (AFB1) electrochemical immunosensor was developed by the immobilisation of aflatoxin B1-bovine serum albumin (AFB1-BSA) conjugate on a polythionine (PTH)/gold nanoparticles (AuNP)-modified glassy carbon electrode (GCE). The surface of the AFB1-BSA conjugate was covered with horseradish peroxidase (HRP), in order to prevent non-specific binding of the immunosensors with ions in the test solution. The AFB1 immunosensor exhibited a quasi-reversible electrochemistry as indicated by a cyclic voltammetric (CV) peak separation (ΔEp) value of 62 mV. The experimental procedure for the detection of AFB1 involved the setting up of a competition between free AFB1 and the immobilised AFB1-BSA conjugate for the binding sites of free anti-aflatoxin B1 (anti-AFB1) antibody. The immunosensor’s differential pulse voltammetry (DPV) responses (peak currents) decreased as the concentration of free AFB1 increased within a dynamic linear range (DLR) of 0.6 - 2.4 ng/mL AFB1 and a limit of detection (LOD) of 0.07 ng/mL AFB1. This immunosensing procedure eliminates the need for enzyme-labeled secondary antibodies normally used in conventional ELISA–based immunosensors. Full article
(This article belongs to the Special Issue Toxin Sensors)
Open AccessArticle
Objective Error Criterion for Evaluation of Mapping Accuracy Based on Sensor Time-of-Flight Measurements
Sensors 2008, 8(12), 8248-8261; https://doi.org/10.3390/s8128248
Received: 24 September 2008 / Revised: 2 December 2007 / Accepted: 2 December 2008 / Published: 15 December 2008
Cited by 5 | Viewed by 5687 | PDF Full-text (675 KB) | HTML Full-text | XML Full-text
Abstract
An objective error criterion is proposed for evaluating the accuracy of maps of unknown environments acquired by making range measurements with different sensing modalities and processing them with different techniques. The criterion can also be used for the assessment of goodness of fit [...] Read more.
An objective error criterion is proposed for evaluating the accuracy of maps of unknown environments acquired by making range measurements with different sensing modalities and processing them with different techniques. The criterion can also be used for the assessment of goodness of fit of curves or shapes fitted to map points. A demonstrative example from ultrasonic mapping is given based on experimentally acquired time-of-flight measurements and compared with a very accurate laser map, considered as absolute reference. The results of the proposed criterion are compared with the Hausdorff metric and the median error criterion results. The error criterion is sufficiently general and flexible that it can be applied to discrete point maps acquired with other mapping techniques and sensing modalities as well. Full article
(This article belongs to the Special Issue Sensor Algorithms)
Open AccessArticle
Eliminating the Interference of Oxygen for Sensing Hydrogen Peroxide with the Polyaniline Modified Electrode
Sensors 2008, 8(12), 8237-8247; https://doi.org/10.3390/s8128237
Received: 19 October 2008 / Revised: 24 November 2008 / Accepted: 10 December 2008 / Published: 12 December 2008
Cited by 17 | Viewed by 5281 | PDF Full-text (991 KB) | HTML Full-text | XML Full-text
Abstract
Polyaniline (PANI) has been shown to possess excellent catalytic activity toward oxygen reduction, however, this molecule may interfere with the electrochemical measurement of other targets when using a polyaniline modified platinum (PANI/Pt) electrode. In this study, we have demonstrated the considerable effects of [...] Read more.
Polyaniline (PANI) has been shown to possess excellent catalytic activity toward oxygen reduction, however, this molecule may interfere with the electrochemical measurement of other targets when using a polyaniline modified platinum (PANI/Pt) electrode. In this study, we have demonstrated the considerable effects of dissolved oxygen on the sensing of hydrogen peroxide with the PANI/Pt electrode. Accordingly, we proposed a strategy to eliminate the influence of dissolved oxygen with oxygen scavengers. Our results indicated that as an oxygen scavenger sodium thiosulfate was very effective in the removal of dissolved oxygen from the sample solution, and had negligible effect on the quantification of hydrogen peroxide when its applied concentration was below 1 mM. Full article
(This article belongs to the Section Chemical Sensors)
Open AccessArticle
A Modified Subpulse SAR Processing Procedure Based on the Range-Doppler Algorithm for Synthetic Wideband Waveforms
Sensors 2008, 8(12), 8224-8236; https://doi.org/10.3390/s8128224
Received: 14 October 2008 / Revised: 10 December 2008 / Accepted: 10 December 2008 / Published: 11 December 2008
Cited by 5 | Viewed by 7863 | PDF Full-text (563 KB) | HTML Full-text | XML Full-text
Abstract
Synthetic wideband waveforms (SWW) combine a stepped frequency CW waveform and a chirp signal waveform to achieve high range resolution without requiring a large bandwidth or the consequent very high sampling rate. If an efficient algorithm like the range-Doppler algorithm (RDA) is used [...] Read more.
Synthetic wideband waveforms (SWW) combine a stepped frequency CW waveform and a chirp signal waveform to achieve high range resolution without requiring a large bandwidth or the consequent very high sampling rate. If an efficient algorithm like the range-Doppler algorithm (RDA) is used to acquire the SAR images for synthetic wideband signals, errors occur due to approximations, so the images may not show the best possible result. This paper proposes a modified subpulse SAR processing algorithm for synthetic wideband signals which is based on RDA. An experiment with an automobile-based SAR system showed that the proposed algorithm is quite accurate with a considerable improvement in resolution and quality of the obtained SAR image. Full article
(This article belongs to the Special Issue Synthetic Aperture Radar (SAR))
Open AccessArticle
Rural Land Use Change during 1986–2002 in Lijiang, China, Based on Remote Sensing and GIS Data
Sensors 2008, 8(12), 8201-8223; https://doi.org/10.3390/s8128201
Received: 25 November 2008 / Revised: 8 December 2008 / Accepted: 8 December 2008 / Published: 11 December 2008
Cited by 32 | Viewed by 9294 | PDF Full-text (719 KB) | HTML Full-text | XML Full-text
Abstract
As a local environmental issue with global importance, land use/land cover change (LUCC) has always been one of the key issues in geography and environmental studies with the expansion of regional case studies. While most of LUCC studies in China have focused on [...] Read more.
As a local environmental issue with global importance, land use/land cover change (LUCC) has always been one of the key issues in geography and environmental studies with the expansion of regional case studies. While most of LUCC studies in China have focused on urban land use change, meanwhile, compared with the rapid change of urban land use in the coastal areas of eastern China, slow but distinct rural land use changes have also occurred in the mountainous areas of western China since the late 1980s. In this case through a study in Lijiang County of Yunnan Province, with the application of remote sensing data and geographic information system techniques, the process of rural land use change in mountain areas of western China was monitored through extensive statistical analysis of detailed regional data. The results showed significant increases in construction land, paddy field and dry land, and a decrease in dense forest land and waste grassland between 1986 and 2002. The conversions between dense forest land and sparse forest land, grassland, waste grassland and dry land were the primary processes of rural land use change. Sparse forest land had the highest rate of land use change, with glacier or snow-capped land the lowest; while human settlement and rural economic development were found to be the main driving forces of regional difference in the integrated land use change rate among the 24 towns of Lijiang County. Quantified through landscape metrics, spatial patterns of rural land use change were represented as an increase in landscape diversity and landscape fragmentation, and the regularization of patch shapes, suggesting the intensification of human disturbances and degradation of ecological quality in the rural landscape. Full article
(This article belongs to the Section Remote Sensors, Control, and Telemetry)
Open AccessArticle
Inversion of Electromagnetic Models for Bare Soil Parameter Estimation from Multifrequency Polarimetric SAR Data
Sensors 2008, 8(12), 8181-8200; https://doi.org/10.3390/s8128181
Received: 23 September 2008 / Revised: 11 November 2008 / Accepted: 2 December 2008 / Published: 11 December 2008
Cited by 33 | Viewed by 7621 | PDF Full-text (297 KB) | HTML Full-text | XML Full-text
Abstract
The potentiality of polarimetric SAR data for the estimation of bare soil geophysical parameters (i.e., roughness and soil moisture) is investigated in this work. For this purpose, two forward models available in the literature, able to simulate the measurements of a multifrequency radar [...] Read more.
The potentiality of polarimetric SAR data for the estimation of bare soil geophysical parameters (i.e., roughness and soil moisture) is investigated in this work. For this purpose, two forward models available in the literature, able to simulate the measurements of a multifrequency radar polarimeter, have been implemented for use within an inversion scheme. A multiplicative noise has been considered in the multidimensional space of the elements of the polarimetric Covariance Matrix, by adopting a complex Wishart distribution to account for speckle effects. An additive error has been also introduced on the simulated measurements to account for calibration and model errors. Maximum a Posteriori Probability and Minimum Variance criteria have been considered to perform the inversion. As for the algorithms to implement the criteria, simple optimization/integration procedures have been used. A Neural Network approach has been adopted as well. A correlation between the roughness parameters has been also supposed in the simulation as a priori information, to evaluate its effect on the estimation accuracy. The methods have been tested on simulated data to compare their performances as function of number of looks, incidence angles and frequency bands, thus identifying the best radar configuration in terms of estimation accuracy. Polarimetric measurements acquired during MAC Europe and SIR-C campaigns, over selected bare soil fields, have been also used as validation data. Full article
(This article belongs to the Special Issue Synthetic Aperture Radar (SAR))
Open AccessReview
Water Productivity Mapping (WPM) Using Landsat ETM+ Data for the Irrigated Croplands of the Syrdarya River Basin in Central Asia
Sensors 2008, 8(12), 8156-8180; https://doi.org/10.3390/s8128156
Received: 23 October 2008 / Revised: 26 November 2008 / Accepted: 5 December 2008 / Published: 10 December 2008
Cited by 18 | Viewed by 12670 | PDF Full-text (1614 KB) | HTML Full-text | XML Full-text
Abstract
The overarching goal of this paper was to espouse methods and protocols for water productivity mapping (WPM) using high spatial resolution Landsat remote sensing data. In a world where land and water for agriculture are becoming increasingly scarce, growing “more crop per drop” [...] Read more.
The overarching goal of this paper was to espouse methods and protocols for water productivity mapping (WPM) using high spatial resolution Landsat remote sensing data. In a world where land and water for agriculture are becoming increasingly scarce, growing “more crop per drop” (increasing water productivity) becomes crucial for food security of future generations. The study used time-series Landsat ETM+ data to produce WPMs of irrigated crops, with emphasis on cotton in the Galaba study area in the Syrdarya river basin of Central Asia. The WPM methods and protocols using remote sensing data consisted of: (1) crop productivity (ton/ha) maps (CPMs) involvingcrop type classification, crop yield and biophysical modeling, and extrapolating yield models to larger areas using remotely sensed data; (2) crop water use (m3/ha) maps (WUMs) (or actual seasonal evapotranspiration or actual ET) developed through Simplified Surface Energy Balance (SSEB) model; and (3) water productivity (kg/m3) maps (WPMs) produced by dividing raster layers of CPMs by WUMs. The SSEB model calculated WUMs (actual ET) by multiplying the ET fractionby reference ET. The ETfraction was determined using Landsat thermal imagery by selecting the “hot” pixels (zero ET) and “cold” pixels (maximum ET). The grass reference ET was calculated by FAO Penman-Monteith method using meteorological data. The WPMs for the Galaba study area demonstrated a wide variations (0-0.54 kg/m3) in water productivity of cotton fields with overwhelming proportion (87%) of the area having WP less than 0.30 kg/m3, 11% of the area having WP in range of 0.30-0.36 kg/m3, and only 2% of the area with WP greater than 0.36 kg/m3. These results clearly imply that there are opportunities for significant WP increases in overwhelming proportion of the existing croplands. The areas of low WP are spatially pin-pointed and can be used as focus for WP improvements through better land and water management practices. Full article
(This article belongs to the Section Remote Sensors, Control, and Telemetry)
Open AccessArticle
Use of Automatic Target Recognition System for the Displacement Measurements in a Small Diameter Tunnel Ahead of the Face of the Motorway Tunnel During Excavation
Sensors 2008, 8(12), 8139-8155; https://doi.org/10.3390/s8128139
Received: 5 November 2008 / Revised: 5 December 2008 / Accepted: 9 December 2008 / Published: 10 December 2008
Cited by 3 | Viewed by 8443 | PDF Full-text (812 KB) | HTML Full-text | XML Full-text
Abstract
During construction of the Šentvid tunnel a unique opportunity arose to measure the 3D displacements ahead of the motorway tunnel excavation face, since the exploratory tunnel was already constructed in the axis of the main tunnel. According to reviewed literature such measurements had [...] Read more.
During construction of the Šentvid tunnel a unique opportunity arose to measure the 3D displacements ahead of the motorway tunnel excavation face, since the exploratory tunnel was already constructed in the axis of the main tunnel. According to reviewed literature such measurements had not been performed yet and several problems regarding equipment and complete scheme of the experiment needed to be overcome. The paper gives a brief description of the Šentvid tunnel project, presents significant factors that affected the choice of the geodetic equipment and describes the scheme of the experiment. A special attention is focused on the problems relating to the operation of the instrument in demanding environmental conditions (water, dust). Full article
(This article belongs to the Section Chemical Sensors)
Open AccessArticle
Wireless Monitoring of Automobile Tires for Intelligent Tires
Sensors 2008, 8(12), 8123-8138; https://doi.org/10.3390/s8128123
Received: 14 November 2008 / Revised: 4 December 2008 / Accepted: 8 December 2008 / Published: 9 December 2008
Cited by 60 | Viewed by 11291 | PDF Full-text (603 KB) | HTML Full-text | XML Full-text
Abstract
This review discusses key technologies of intelligent tires focusing on sensors and wireless data transmission. Intelligent automobile tires, which monitor their pressure, deformation, wheel loading, friction, or tread wear, are expected to improve the reliability of tires and tire control systems. However, in [...] Read more.
This review discusses key technologies of intelligent tires focusing on sensors and wireless data transmission. Intelligent automobile tires, which monitor their pressure, deformation, wheel loading, friction, or tread wear, are expected to improve the reliability of tires and tire control systems. However, in installing sensors in a tire, many problems have to be considered, such as compatibility of the sensors with tire rubber, wireless transmission, and battery installments. As regards sensing, this review discusses indirect methods using existing sensors, such as that for wheel speed, and direct methods, such as surface acoustic wave sensors and piezoelectric sensors. For wireless transmission, passive wireless methods and energy harvesting are also discussed. Full article
(This article belongs to the Special Issue Wireless Sensor Technologies and Applications)
Open AccessArticle
Land Use/Cover Dynamics in Response to Changes in Environmental and Socio-Political Forces in the Upper Reaches of Yangtze River, China
Sensors 2008, 8(12), 8104-8122; https://doi.org/10.3390/s8128104
Received: 11 November 2008 / Revised: 30 November 2008 / Accepted: 5 December 2008 / Published: 9 December 2008
Cited by 17 | Viewed by 9630 | PDF Full-text (314 KB) | HTML Full-text | XML Full-text
Abstract
Land use/cover change (LUCC), which results from the complex interaction of social, ecological and geophysical processes, is a major issue and the main cause of global environmental change. This study analyzed the land use/cover dynamics and their environmental and socio-political forces in the [...] Read more.
Land use/cover change (LUCC), which results from the complex interaction of social, ecological and geophysical processes, is a major issue and the main cause of global environmental change. This study analyzed the land use/cover dynamics and their environmental and socio-political forces in the upper reaches of Yangtze River from 1980 to 2000 by using remote sensing, climatic and socio-economic data from both research institutes and government departments. The results indicated that there had been significant land use/cover changes between 1980 and 2000 in the study area, which were characterized by a severe replacement of cropland and woodland with grassland and built-up land. The transition matrices highlight the dominant dynamic events and the internal conversions between land use/cover types during the study period and reveal two distinct transition phases. Land use/cover changes in the upper reaches of Yangtze River during 1980 to 2000, while restricted by environmental attributes, were strongly driven by socio-political factors. However, excessively pursuing higher land use benefits likely results in serious environmental degradation. This study suggests that the restructuring of land use should be based on land suitability and sustainable protection of fragile environment in the upper reaches of Yangtze River. A thorough comprehension of historical changes will enhance our capability to predict future land use change and contribute to effective management strategies and policies for the rational land use. Full article
(This article belongs to the Section Remote Sensors, Control, and Telemetry)
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Open AccessArticle
Globally Optimal Multisensor Distributed Random Parameter Matrices Kalman Filtering Fusion with Applications
Sensors 2008, 8(12), 8086-8103; https://doi.org/10.3390/s8128086
Received: 28 August 2008 / Revised: 26 November 2008 / Accepted: 3 December 2008 / Published: 8 December 2008
Cited by 64 | Viewed by 8080 | PDF Full-text (187 KB) | HTML Full-text | XML Full-text
Abstract
This paper proposes a new distributed Kalman filtering fusion with random state transition and measurement matrices, i.e., random parameter matrices Kalman filtering. It is proved that under a mild condition the fused state estimate is equivalent to the centralized Kalman filtering using all [...] Read more.
This paper proposes a new distributed Kalman filtering fusion with random state transition and measurement matrices, i.e., random parameter matrices Kalman filtering. It is proved that under a mild condition the fused state estimate is equivalent to the centralized Kalman filtering using all sensor measurements; therefore, it achieves the best performance. More importantly, this result can be applied to Kalman filtering with uncertain observations including the measurement with a false alarm probability as a special case, as well as, randomly variant dynamic systems with multiple models. Numerical examples are given which support our analysis and show significant performance loss of ignoring the randomness of the parameter matrices. Full article
(This article belongs to the Special Issue Aerospace Sensor Systems)
Open AccessArticle
Spectral and Spatial-Based Classification for Broad-Scale Land Cover Mapping Based on Logistic Regression
Sensors 2008, 8(12), 8067-8085; https://doi.org/10.3390/s8128067
Received: 9 October 2008 / Revised: 5 November 2008 / Accepted: 17 November 2008 / Published: 8 December 2008
Cited by 15 | Viewed by 8093 | PDF Full-text (615 KB) | HTML Full-text | XML Full-text
Abstract
Improvement of satellite sensor characteristics motivates the development of new techniques for satellite image classification. Spatial information seems to be critical in classification processes, especially for heterogeneous and complex landscapes such as those observed in the Mediterranean basin. In our study, a spectral [...] Read more.
Improvement of satellite sensor characteristics motivates the development of new techniques for satellite image classification. Spatial information seems to be critical in classification processes, especially for heterogeneous and complex landscapes such as those observed in the Mediterranean basin. In our study, a spectral classification method of a LANDSAT-5 TM imagery that uses several binomial logistic regression models was developed, evaluated and compared to the familiar parametric maximum likelihood algorithm. The classification approach based on logistic regression modelling was extended to a contextual one by using autocovariates to consider spatial dependencies of every pixel with its neighbours. Finally, the maximum likelihood algorithm was upgraded to contextual by considering typicality, a measure which indicates the strength of class membership. The use of logistic regression for broad-scale land cover classification presented higher overall accuracy (75.61%), although not statistically significant, than the maximum likelihood algorithm (64.23%), even when the latter was refined following a spatial approach based on Mahalanobis distance (66.67%). However, the consideration of the spatial autocovariate in the logistic models significantly improved the fit of the models and increased the overall accuracy from 75.61% to 80.49%. Full article
(This article belongs to the Special Issue Remote Sensing of Land Surface Properties, Patterns and Processes)
Open AccessReview
Energy Options for Wireless Sensor Nodes
Sensors 2008, 8(12), 8037-8066; https://doi.org/10.3390/s8128037
Received: 24 September 2008 / Revised: 3 December 2008 / Accepted: 5 December 2008 / Published: 8 December 2008
Cited by 100 | Viewed by 12267 | PDF Full-text (1091 KB) | HTML Full-text | XML Full-text
Abstract
Reduction in size and power consumption of consumer electronics has opened up many opportunities for low power wireless sensor networks. One of the major challenges is in supporting battery operated devices as the number of nodes in a network grows. The two main [...] Read more.
Reduction in size and power consumption of consumer electronics has opened up many opportunities for low power wireless sensor networks. One of the major challenges is in supporting battery operated devices as the number of nodes in a network grows. The two main alternatives are to utilize higher energy density sources of stored energy, or to generate power at the node from local forms of energy. This paper reviews the state-of-the art technology in the field of both energy storage and energy harvesting for sensor nodes. The options discussed for energy storage include batteries, capacitors, fuel cells, heat engines and betavoltaic systems. The field of energy harvesting is discussed with reference to photovoltaics, temperature gradients, fluid flow, pressure variations and vibration harvesting. Full article
(This article belongs to the Special Issue Wireless Sensor Technologies and Applications)
Open AccessArticle
Measurements of Impedance and Attenuation at CENELEC Bands for Power Line Communications Systems
Sensors 2008, 8(12), 8027-8036; https://doi.org/10.3390/s8128027
Received: 12 August 2008 / Revised: 1 December 2008 / Accepted: 5 December 2008 / Published: 8 December 2008
Cited by 23 | Viewed by 7830 | PDF Full-text (119 KB) | HTML Full-text | XML Full-text
Abstract
Power line impedance is a very important parameter on the design of power line communications (PLC) modem architecture. Variations on the impedance of the power line affect the communications circuit performance. In order to determine impedance of the power lines, measurements were carried [...] Read more.
Power line impedance is a very important parameter on the design of power line communications (PLC) modem architecture. Variations on the impedance of the power line affect the communications circuit performance. In order to determine impedance of the power lines, measurements were carried out in Turkey at frequencies ranging from 10 to 170 kHz, (CENELEC A,B,C,D bands). Measurements were conducted in three categories: rural, urban and the industrial power lines. Experimental results are presented in graphical form. The measured impedances were determined as 3-17 ohms, 1-17 ohms, and 1-21 ohms for rural, urban and the industrial lines, respectively. A set of the formulas between impedance and frequency are developed on the power lines using the regression analysis from the obtained empirical data. Signal attenuations on the power lines in the CENELEC band are also measured for rural, urban and industrial regions. Attenuation measurements are repeated for phase-neutral, phase-ground and the neutral-ground conductors. Signal attenuations are found to be 4-30 dB, for different power lines. To establish validity of obtained results for the design of PLC systems, the results are compared with previous investigations. The effects of some household appliances such as TV, PC, UPS, lighting and cooling systems on the impedances and the attenuations for power line communications systems are observed. Some suggestions and proposals are presented for PLC modem designers. Full article
(This article belongs to the Section Chemical Sensors)
Open AccessArticle
Retrieval of Surface Air Specific Humidity Over the Ocean Using AMSR-E Measurements
Sensors 2008, 8(12), 8016-8026; https://doi.org/10.3390/s8128016
Received: 7 October 2008 / Revised: 29 November 2008 / Accepted: 3 December 2008 / Published: 8 December 2008
Cited by 8 | Viewed by 6916 | PDF Full-text (710 KB) | HTML Full-text | XML Full-text
Abstract
We have developed a new algorithm to estimate the surface air specific humidity over the ocean from AMSR-E data. It should be noted that remarkably reduced random errors of the estimated surface air specific humidity result from using the surface air specific humidity [...] Read more.
We have developed a new algorithm to estimate the surface air specific humidity over the ocean from AMSR-E data. It should be noted that remarkably reduced random errors of the estimated surface air specific humidity result from using the surface air specific humidity provided by reanalysis data. We validated our new algorithm using independent ship and buoy data. The bias, RMS error, and correlation coefficient of the products obtained using our algorithm for global buoys are 0.38 g/kg, 0.61 g/kg and 0.99, respectively. It should be noted that surface specific humidity having similar accuracy to the reanalysis data near in situ data could be derived from AMSR-E data by the present algorithm. Full article
(This article belongs to the Special Issue Ocean Remote Sensing)
Open AccessArticle
Sparse Detector Imaging Sensor with Two-Class Silhouette Classification
Sensors 2008, 8(12), 7996-8015; https://doi.org/10.3390/s8127996
Received: 4 November 2008 / Revised: 1 December 2008 / Accepted: 4 December 2008 / Published: 8 December 2008
Cited by 26 | Viewed by 8842 | PDF Full-text (456 KB) | HTML Full-text | XML Full-text
Abstract
This paper presents the design and test of a simple active near-infrared sparse detector imaging sensor. The prototype of the sensor is novel in that it can capture remarkable silhouettes or profiles of a wide-variety of moving objects, including humans, animals, and vehicles [...] Read more.
This paper presents the design and test of a simple active near-infrared sparse detector imaging sensor. The prototype of the sensor is novel in that it can capture remarkable silhouettes or profiles of a wide-variety of moving objects, including humans, animals, and vehicles using a sparse detector array comprised of only sixteen sensing elements deployed in a vertical configuration. The prototype sensor was built to collect silhouettes for a variety of objects and to evaluate several algorithms for classifying the data obtained from the sensor into two classes: human versus non-human. Initial tests show that the classification of individually sensed objects into two classes can be achieved with accuracy greater than ninety-nine percent (99%) with a subset of the sixteen detectors using a representative dataset consisting of 512 signatures. The prototype also includes a Webservice interface such that the sensor can be tasked in a network-centric environment. The sensor appears to be a low-cost alternative to traditional, high-resolution focal plane array imaging sensors for some applications. After a power optimization study, appropriate packaging, and testing with more extensive datasets, the sensor may be a good candidate for deployment in vast geographic regions for a myriad of intelligent electronic fence and persistent surveillance applications, including perimeter security scenarios. Full article
(This article belongs to the Special Issue Image Sensors 2009)
Open AccessArticle
A Passive Wireless Temperature Sensor for Harsh Environment Applications
Sensors 2008, 8(12), 7982-7995; https://doi.org/10.3390/s8127982
Received: 21 October 2008 / Revised: 3 December 2008 / Accepted: 4 December 2008 / Published: 8 December 2008
Cited by 64 | Viewed by 14512 | PDF Full-text (284 KB) | HTML Full-text | XML Full-text
Abstract
High temperature sensors capable of operating in harsh environments are needed in order to prevent disasters caused by structural or system functional failures due to increasing temperatures. Most existing temperature sensors do not satisfy the needs because they require either physical contact or [...] Read more.
High temperature sensors capable of operating in harsh environments are needed in order to prevent disasters caused by structural or system functional failures due to increasing temperatures. Most existing temperature sensors do not satisfy the needs because they require either physical contact or a battery power supply for signal communication, and furthermore, neither of them can withstand high temperatures nor rotating applications. This paper presents a novel passive wireless temperature sensor, suitable for working in harsh environments for high temperature rotating component monitoring. A completely passive LC resonant telemetry scheme, relying on a frequency variation output, which has been applied successfully in pressure, humidity and chemical measurement, is integrated with a unique high-k temperature sensitive ceramic material, in order to measure the temperatures without contacts, active elements, or power supplies within the sensor. In this paper, the high temperature sensor design and performance analysis are conducted based on mechanical and electrical modeling, in order to maximize the sensing distance, the Q factor and the sensitivity. In the end, the sensor prototype is fabricated and calibrated successfully up to 235ºC, so that the concept of temperature sensing through passive wireless communication is proved. Full article
(This article belongs to the Special Issue Wireless Sensor Technologies and Applications)
Open AccessArticle
Horizontal Positional Accuracy of Google Earth’s High-Resolution Imagery Archive
Sensors 2008, 8(12), 7973-7981; https://doi.org/10.3390/s8127973
Received: 1 July 2008 / Revised: 13 November 2008 / Accepted: 2 December 2008 / Published: 8 December 2008
Cited by 135 | Viewed by 13010 | PDF Full-text (950 KB) | HTML Full-text | XML Full-text
Abstract
Google Earth now hosts high-resolution imagery that spans twenty percent of the Earth’s landmass and more than a third of the human population. This contemporary highresolution archive represents a significant, rapidly expanding, cost-free and largely unexploited resource for scientific inquiry. To increase the [...] Read more.
Google Earth now hosts high-resolution imagery that spans twenty percent of the Earth’s landmass and more than a third of the human population. This contemporary highresolution archive represents a significant, rapidly expanding, cost-free and largely unexploited resource for scientific inquiry. To increase the scientific utility of this archive, we address horizontal positional accuracy (georegistration) by comparing Google Earth with Landsat GeoCover scenes over a global sample of 436 control points located in 109 cities worldwide. Landsat GeoCover is an orthorectified product with known absolute positional accuracy of less than 50 meters root-mean-squared error (RMSE). Relative to Landsat GeoCover, the 436 Google Earth control points have a positional accuracy of 39.7 meters RMSE (error magnitudes range from 0.4 to 171.6 meters). The control points derived from satellite imagery have an accuracy of 22.8 meters RMSE, which is significantly more accurate than the 48 control-points based on aerial photography (41.3 meters RMSE; t-test p-value < 0.01). The accuracy of control points in more-developed countries is 24.1 meters RMSE, which is significantly more accurate than the control points in developing countries (44.4 meters RMSE; t-test p-value < 0.01). These findings indicate that Google Earth highresolution imagery has a horizontal positional accuracy that is sufficient for assessing moderate-resolution remote sensing products across most of the world’s peri-urban areas. Full article
(This article belongs to the Section Remote Sensors, Control, and Telemetry)
Open AccessReview
Optoelectronic Plethysmography has Improved our Knowledge of Respiratory Physiology and Pathophysiology
Sensors 2008, 8(12), 7951-7972; https://doi.org/10.3390/s8127951
Received: 21 October 2008 / Revised: 25 November 2008 / Accepted: 27 November 2008 / Published: 5 December 2008
Cited by 15 | Viewed by 10320 | PDF Full-text (485 KB) | HTML Full-text | XML Full-text
Abstract
It is well known that the methods actually used to track thoraco-abdominal volume displacement have several limitations. This review evaluates the clinical usefulness of measuring chest wall kinematics by optoelectronic plethysmography [OEP]. OEP provides direct measurements (both absolute and its variations) of the [...] Read more.
It is well known that the methods actually used to track thoraco-abdominal volume displacement have several limitations. This review evaluates the clinical usefulness of measuring chest wall kinematics by optoelectronic plethysmography [OEP]. OEP provides direct measurements (both absolute and its variations) of the volume of the chest wall and its compartments, according to the model of Ward and Macklem, without requiring calibration or subject cooperation. The system is non invasive and does not require a mouthpiece or nose-clip which may modify the pattern of breathing, making the subject aware of his breathing. Also, the precise assessment of compartmental changes in chest wall volumes, combined with pressure measurements, provides a detailed description of the action and control of the different respiratory muscle groups and assessment of chest wall dynamics in a number of physiological and clinical experimental conditions. Full article
(This article belongs to the Special Issue State-of-the-Art Sensors Technology in Italy)
Open AccessArticle
TinyONet: A Cache-Based Sensor Network Bridge Enabling Sensing Data Reusability and Customized Wireless Sensor Network Services
Sensors 2008, 8(12), 7930-7950; https://doi.org/10.3390/s8127930
Received: 7 September 2008 / Revised: 21 November 2008 / Accepted: 1 December 2008 / Published: 5 December 2008
Cited by 5 | Viewed by 9325 | PDF Full-text (614 KB) | HTML Full-text | XML Full-text
Abstract
In recent years, a few protocol bridge research projects have been announced to enable a seamless integration of Wireless Sensor Networks (WSNs) with the TCP/IP network. These studies have ensured the transparent end-to-end communication between two network sides in the node-centric manner. Researchers [...] Read more.
In recent years, a few protocol bridge research projects have been announced to enable a seamless integration of Wireless Sensor Networks (WSNs) with the TCP/IP network. These studies have ensured the transparent end-to-end communication between two network sides in the node-centric manner. Researchers expect this integration will trigger the development of various application domains. However, prior research projects have not fully explored some essential features for WSNs, especially the reusability of sensing data and the data-centric communication. To resolve these issues, we suggested a new protocol bridge system named TinyONet. In TinyONet, virtual sensors play roles as virtual counterparts of physical sensors and they dynamically group to make a functional entity, Slice. Instead of direct interaction with individual physical sensors, each sensor application uses its own WSN service provided by Slices. If a new kind of service is required in TinyONet, the corresponding function can be dynamically added at runtime. Beside the data-centric communication, it also supports the node-centric communication and the synchronous access. In order to show the effectiveness of the system, we implemented TinyONet on an embedded Linux machine and evaluated it with several experimental scenarios. Full article
(This article belongs to the Special Issue Wireless Sensor Technologies and Applications)
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