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Sensors, Volume 12, Issue 10 (October 2012), Pages 12870-14231

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Open AccessArticle Handmade Task Tracking Applied to Cognitive Rehabilitation
Sensors 2012, 12(10), 14214-14231; https://doi.org/10.3390/s121014214
Received: 16 August 2012 / Revised: 8 October 2012 / Accepted: 12 October 2012 / Published: 22 October 2012
Cited by 10 | PDF Full-text (560 KB) | HTML Full-text | XML Full-text
Abstract
This article presents research focused on tracking manual tasks that are applied in cognitive rehabilitation so as to analyze the movements of patients who suffer from Apraxia and Action Disorganization Syndrome (AADS). This kind of patients find executing Activities of Daily Living (ADL)
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This article presents research focused on tracking manual tasks that are applied in cognitive rehabilitation so as to analyze the movements of patients who suffer from Apraxia and Action Disorganization Syndrome (AADS). This kind of patients find executing Activities of Daily Living (ADL) too difficult due to the loss of memory and capacity to carry out sequential tasks or the impossibility of associating different objects with their functions. This contribution is developed from the work of Universidad Politécnica de Madrid and Technical University of Munich in collaboration with The University of Birmingham. The KinectTM for Windows© device is used for this purpose. The data collected is compared to an ultrasonic motion capture system. The results indicate a moderate to strong correlation between signals. They also verify that KinectTM is very suitable and inexpensive. Moreover, it turns out to be a motion-capture system quite easy to implement for kinematics analysis in ADL. Full article
(This article belongs to the Section Physical Sensors)
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Open AccessArticle Mobile Mapping of Sporting Event Spectators Using Bluetooth Sensors: Tour of Flanders 2011
Sensors 2012, 12(10), 14196-14213; https://doi.org/10.3390/s121014196
Received: 22 May 2012 / Revised: 17 October 2012 / Accepted: 18 October 2012 / Published: 22 October 2012
Cited by 13 | PDF Full-text (706 KB) | HTML Full-text | XML Full-text
Abstract
Accurate spatiotemporal information on crowds is a necessity for a better management in general and for the mitigation of potential security risks. The large numbers of individuals involved and their mobility, however, make generation of this information non-trivial. This paper proposes a novel
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Accurate spatiotemporal information on crowds is a necessity for a better management in general and for the mitigation of potential security risks. The large numbers of individuals involved and their mobility, however, make generation of this information non-trivial. This paper proposes a novel methodology to estimate and map crowd sizes using mobile Bluetooth sensors and examines to what extent this methodology represents a valuable alternative to existing traditional crowd density estimation methods. The proposed methodology is applied in a unique case study that uses Bluetooth technology for the mobile mapping of spectators of the Tour of Flanders 2011 road cycling race. The locations of nearly 16,000 cell phones of spectators along the race course were registered and detailed views of the spatiotemporal distribution of the crowd were generated. Comparison with visual head counts from camera footage delivered a detection ratio of 13.0 ± 2.3%, making it possible to estimate the crowd size. To our knowledge, this is the first study that uses mobile Bluetooth sensors to count and map a crowd over space and time. Full article
(This article belongs to the Section Remote Sensors)
Open AccessArticle Intelligent Color Vision System for Ripeness Classification of Oil Palm Fresh Fruit Bunch
Sensors 2012, 12(10), 14179-14195; https://doi.org/10.3390/s121014179
Received: 20 August 2012 / Revised: 5 October 2012 / Accepted: 10 October 2012 / Published: 22 October 2012
Cited by 14 | PDF Full-text (1047 KB) | HTML Full-text | XML Full-text
Abstract
Ripeness classification of oil palm fresh fruit bunches (FFBs) during harvesting is important to ensure that they are harvested during optimum stage for maximum oil production. This paper presents the application of color vision for automated ripeness classification of oil palm FFB. Images
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Ripeness classification of oil palm fresh fruit bunches (FFBs) during harvesting is important to ensure that they are harvested during optimum stage for maximum oil production. This paper presents the application of color vision for automated ripeness classification of oil palm FFB. Images of oil palm FFBs of type DxP Yangambi were collected and analyzed using digital image processing techniques. Then the color features were extracted from those images and used as the inputs for Artificial Neural Network (ANN) learning. The performance of the ANN for ripeness classification of oil palm FFB was investigated using two methods: training ANN with full features and training ANN with reduced features based on the Principal Component Analysis (PCA) data reduction technique. Results showed that compared with using full features in ANN, using the ANN trained with reduced features can improve the classification accuracy by 1.66% and is more effective in developing an automated ripeness classifier for oil palm FFB. The developed ripeness classifier can act as a sensor in determining the correct oil palm FFB ripeness category. Full article
(This article belongs to the Special Issue Sensor-Based Technologies and Processes in Agriculture and Forestry)
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Open AccessArticle Developing a Reading Concentration Monitoring System by Applying an Artificial Bee Colony Algorithm to E-Books in an Intelligent Classroom
Sensors 2012, 12(10), 14158-14178; https://doi.org/10.3390/s121014158
Received: 29 August 2012 / Revised: 8 October 2012 / Accepted: 17 October 2012 / Published: 22 October 2012
Cited by 18 | PDF Full-text (876 KB) | HTML Full-text | XML Full-text
Abstract
A growing number of educational studies apply sensors to improve student learning in real classroom settings. However, how can sensors be integrated into classrooms to help instructors find out students’ reading concentration rates and thus better increase learning effectiveness? The aim of the
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A growing number of educational studies apply sensors to improve student learning in real classroom settings. However, how can sensors be integrated into classrooms to help instructors find out students’ reading concentration rates and thus better increase learning effectiveness? The aim of the current study was to develop a reading concentration monitoring system for use with e-books in an intelligent classroom and to help instructors find out the students’ reading concentration rates. The proposed system uses three types of sensor technologies, namely a webcam, heartbeat sensor, and blood oxygen sensor to detect the learning behaviors of students by capturing various physiological signals. An artificial bee colony (ABC) optimization approach is applied to the data gathered from these sensors to help instructors understand their students’ reading concentration rates in a classroom learning environment. The results show that the use of the ABC algorithm in the proposed system can effectively obtain near-optimal solutions. The system has a user-friendly graphical interface, making it easy for instructors to clearly understand the reading status of their students. Full article
(This article belongs to the Section Physical Sensors)
Open AccessArticle Numerical Study of Opto-Fluidic Ring Resonators for Biosensor Applications
Sensors 2012, 12(10), 14144-14157; https://doi.org/10.3390/s121014144
Received: 22 August 2012 / Revised: 8 October 2012 / Accepted: 17 October 2012 / Published: 22 October 2012
Cited by 6 | PDF Full-text (1344 KB) | HTML Full-text | XML Full-text
Abstract
The opto-fluidic ring resonator (OFRR) biosensor is numerically characterized in whispering gallery mode (WGM). The ring resonator includes a ring, a waveguide and a gap separating the ring and the waveguide. Dependence of the resonance characteristics on the resonator size parameters such as
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The opto-fluidic ring resonator (OFRR) biosensor is numerically characterized in whispering gallery mode (WGM). The ring resonator includes a ring, a waveguide and a gap separating the ring and the waveguide. Dependence of the resonance characteristics on the resonator size parameters such as the ring diameter, the ring thickness, the waveguide width, and the gap width between the ring and the waveguide are investigated. For this purpose, we use the finite element method with COMSOL Multiphysics software to solve the Maxwell’s equations. The resonance frequencies, the free spectral ranges (FSR), the full width at half-maximum (FWHM), finesse (F), and quality factor of the resonances (Q) are examined. The resonant frequencies are dominantly affected by the resonator diameter while the gap width, the ring thickness and the waveguide width have negligible effects on the resonant frequencies. FWHM, the quality factor Q and the finesse F are most strongly affected by the gap width and moderately influenced by the ring diameter, the waveguide width and the ring thickness. In addition, our simulation demonstrates that there is an optimum range of the waveguide width for a given ring resonator and this value is between ~2.25 μm and ~2.75 μm in our case. Full article
(This article belongs to the Section Biosensors)
Open AccessArticle An Embedded Real-Time Red Peach Detection System Based on an OV7670 Camera, ARM Cortex-M4 Processor and 3D Look-Up Tables
Sensors 2012, 12(10), 14129-14143; https://doi.org/10.3390/s121014129
Received: 5 September 2012 / Revised: 15 October 2012 / Accepted: 18 October 2012 / Published: 22 October 2012
Cited by 4 | PDF Full-text (1585 KB) | HTML Full-text | XML Full-text
Abstract
This work proposes the development of an embedded real-time fruit detection system for future automatic fruit harvesting. The proposed embedded system is based on an ARM Cortex-M4 (STM32F407VGT6) processor and an Omnivision OV7670 color camera. The future goal of this embedded vision system
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This work proposes the development of an embedded real-time fruit detection system for future automatic fruit harvesting. The proposed embedded system is based on an ARM Cortex-M4 (STM32F407VGT6) processor and an Omnivision OV7670 color camera. The future goal of this embedded vision system will be to control a robotized arm to automatically select and pick some fruit directly from the tree. The complete embedded system has been designed to be placed directly in the gripper tool of the future robotized harvesting arm. The embedded system will be able to perform real-time fruit detection and tracking by using a three-dimensional look-up-table (LUT) defined in the RGB color space and optimized for fruit picking. Additionally, two different methodologies for creating optimized 3D LUTs based on existing linear color models and fruit histograms were implemented in this work and compared for the case of red peaches. The resulting system is able to acquire general and zoomed orchard images and to update the relative tracking information of a red peach in the tree ten times per second. Full article
(This article belongs to the Special Issue Sensor-Based Technologies and Processes in Agriculture and Forestry)
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Open AccessArticle Automatic Suppression of Intense Monochromatic Light in Electro-Optical Sensors
Sensors 2012, 12(10), 14113-14128; https://doi.org/10.3390/s121014113
Received: 20 September 2012 / Revised: 28 September 2012 / Accepted: 18 October 2012 / Published: 19 October 2012
Cited by 13 | PDF Full-text (1141 KB) | HTML Full-text | XML Full-text
Abstract
Electro-optical imaging sensors are widely distributed and used for many different tasks. Due to technical improvements, their pixel size has been steadily decreasing, resulting in a reduced saturation capacity. As a consequence, this progress makes them susceptible to intense point light sources. Developments
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Electro-optical imaging sensors are widely distributed and used for many different tasks. Due to technical improvements, their pixel size has been steadily decreasing, resulting in a reduced saturation capacity. As a consequence, this progress makes them susceptible to intense point light sources. Developments in laser technology have led to very compact and powerful laser sources of any wavelength in the visible and near infrared spectral region, offered as laser pointers. The manifold of wavelengths makes it difficult to encounter sensor saturation over the complete operating waveband by conventional measures like absorption or interference filters. We present a concept for electro-optical sensors to suppress overexposure in the visible spectral region. The key element of the concept is a spatial light modulator in combination with wavelength multiplexing. This approach allows spectral filtering within a localized area in the field of view of the sensor. The system offers the possibility of automatic reduction of overexposure by monochromatic laser radiation. Full article
(This article belongs to the Special Issue State-of-the-Art Sensors Technology in Germany 2012)
Open AccessArticle Detection of Interference Phase by Digital Computation of Quadrature Signals in Homodyne Laser Interferometry
Sensors 2012, 12(10), 14095-14112; https://doi.org/10.3390/s121014095
Received: 31 August 2012 / Revised: 10 October 2012 / Accepted: 12 October 2012 / Published: 19 October 2012
Cited by 27 | PDF Full-text (480 KB) | HTML Full-text | XML Full-text
Abstract
We have proposed an approach to the interference phase extraction in the homodyne laser interferometry. The method employs a series of computational steps to reconstruct the signals for quadrature detection from an interference signal from a non-polarising interferometer sampled by a simple photodetector.
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We have proposed an approach to the interference phase extraction in the homodyne laser interferometry. The method employs a series of computational steps to reconstruct the signals for quadrature detection from an interference signal from a non-polarising interferometer sampled by a simple photodetector. The complexity trade-off is the use of laser beam with frequency modulation capability. It is analytically derived and its validity and performance is experimentally verified. The method has proven to be a feasible alternative for the traditional homodyne detection since it performs with comparable accuracy, especially where the optical setup complexity is principal issue and the modulation of laser beam is not a heavy burden (e.g., in multi-axis sensor or laser diode based systems). Full article
(This article belongs to the Special Issue Laser Sensing and Imaging)
Open AccessArticle Refractive Index Compensation in Over-Determined Interferometric Systems
Sensors 2012, 12(10), 14084-14094; https://doi.org/10.3390/s121014084
Received: 4 September 2012 / Revised: 11 October 2012 / Accepted: 12 October 2012 / Published: 19 October 2012
Cited by 23 | PDF Full-text (966 KB) | HTML Full-text | XML Full-text
Abstract
We present an interferometric technique based on a differential interferometry setup for measurement under atmospheric conditions. The key limiting factor in any interferometric dimensional measurement are fluctuations of the refractive index of air representing a dominating source of uncertainty when evaluated indirectly from
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We present an interferometric technique based on a differential interferometry setup for measurement under atmospheric conditions. The key limiting factor in any interferometric dimensional measurement are fluctuations of the refractive index of air representing a dominating source of uncertainty when evaluated indirectly from the physical parameters of the atmosphere. Our proposal is based on the concept of an over-determined interferometric setup where a reference length is derived from a mechanical frame made from a material with a very low thermal coefficient. The technique allows one to track the variations of the refractive index of air on-line directly in the line of the measuring beam and to compensate for the fluctuations. The optical setup consists of three interferometers sharing the same beam path where two measure differentially the displacement while the third evaluates the changes in the measuring range, acting as a tracking refractometer. The principle is demonstrated in an experimental setup. Full article
(This article belongs to the Section Physical Sensors)
Open AccessArticle FPGA-Based Multiprocessor System for Injection Molding Control
Sensors 2012, 12(10), 14068-14083; https://doi.org/10.3390/s121014068
Received: 13 August 2012 / Revised: 27 September 2012 / Accepted: 12 October 2012 / Published: 18 October 2012
Cited by 2 | PDF Full-text (636 KB) | HTML Full-text | XML Full-text
Abstract
The plastic industry is a very important manufacturing sector and injection molding is a widely used forming method in that industry. The contribution of this work is the development of a strategy to retrofit control of an injection molding machine based on an
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The plastic industry is a very important manufacturing sector and injection molding is a widely used forming method in that industry. The contribution of this work is the development of a strategy to retrofit control of an injection molding machine based on an embedded system microprocessors sensor network on a field programmable gate array (FPGA) device. Six types of embedded processors are included in the system: a smart-sensor processor, a micro fuzzy logic controller, a programmable logic controller, a system manager, an IO processor and a communication processor. Temperature, pressure and position are controlled by the proposed system and experimentation results show its feasibility and robustness. As validation of the present work, a particular sample was successfully injected. Full article
(This article belongs to the Section Sensor Networks)
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Open AccessArticle Cooperative Suction by Vertical Capillary Array Pump for Controlling Flow Profiles of Microfluidic Sensor Chips
Sensors 2012, 12(10), 14053-14067; https://doi.org/10.3390/s121014053
Received: 23 August 2012 / Revised: 27 September 2012 / Accepted: 10 October 2012 / Published: 18 October 2012
Cited by 7 | PDF Full-text (677 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
A passive pump consisting of integrated vertical capillaries has been developed for a microfluidic chip as an useful component with an excellent flow volume and flow rate. A fluidic chip built into a passive pump was used by connecting the bottoms of all
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A passive pump consisting of integrated vertical capillaries has been developed for a microfluidic chip as an useful component with an excellent flow volume and flow rate. A fluidic chip built into a passive pump was used by connecting the bottoms of all the capillaries to a top surface consisting of a thin layer channel in the microfluidic chip where the thin layer channel depth was smaller than the capillary radius. As a result the vertical capillaries drew fluid cooperatively rather than independently, thus exerting the maximum suction efficiency at every instance. This meant that a flow rate was realized that exhibited little variation and without any external power or operation. A microfluidic chip built into this passive pump had the ability to achieve a quasi-steady rather than a rapidly decreasing flow rate, which is a universal flow characteristic in an ordinary capillary. Full article
(This article belongs to the Special Issue Microfluidic Devices)
Open AccessArticle Thermoresponsive Magnetic Nano-Biosensors for Rapid Measurements of Inorganic Arsenic and Cadmium
Sensors 2012, 12(10), 14041-14052; https://doi.org/10.3390/s121014041
Received: 9 July 2012 / Revised: 3 September 2012 / Accepted: 8 October 2012 / Published: 18 October 2012
Cited by 7 | PDF Full-text (397 KB) | HTML Full-text | XML Full-text
Abstract
Green fluorescent protein-tagged sensor proteins, ArsR-GFP and CadC-GFP, have been produced as biosensors for simple and low-cost quantification of As(III) or Cd(II). In this study, the sensor protein-promoter DNA complexes were reconstructed on the surfaces of magnetic particles of different sizes. After the
[...] Read more.
Green fluorescent protein-tagged sensor proteins, ArsR-GFP and CadC-GFP, have been produced as biosensors for simple and low-cost quantification of As(III) or Cd(II). In this study, the sensor protein-promoter DNA complexes were reconstructed on the surfaces of magnetic particles of different sizes. After the surface modification all the particles could be attracted by magnets, and released different amounts of GFP-tagged protein, according to the metal concentrations within 5 min, which caused significant increases in fluorescence. A detection limit of 1 µg/L for As(III) and Cd(II) in purified water was obtained only with the nanoparticles exhibiting enough magnetization after heat treatment for 1 min. Therefore, thermoresponsive magnetic nano-biosensors offer great advantages of rapidity and sensitivity for the measurement of the toxic metals in drinking water. Full article
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Open AccessArticle A Hybrid Sensing Approach for Pure and Adulterated Honey Classification
Sensors 2012, 12(10), 14022-14040; https://doi.org/10.3390/s121014022
Received: 17 August 2012 / Revised: 19 September 2012 / Accepted: 29 September 2012 / Published: 17 October 2012
Cited by 33 | PDF Full-text (614 KB) | HTML Full-text | XML Full-text
Abstract
This paper presents a comparison between data from single modality and fusion methods to classify Tualang honey as pure or adulterated using Linear Discriminant Analysis (LDA) and Principal Component Analysis (PCA) statistical classification approaches. Ten different brands of certified pure Tualang honey were
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This paper presents a comparison between data from single modality and fusion methods to classify Tualang honey as pure or adulterated using Linear Discriminant Analysis (LDA) and Principal Component Analysis (PCA) statistical classification approaches. Ten different brands of certified pure Tualang honey were obtained throughout peninsular Malaysia and Sumatera, Indonesia. Various concentrations of two types of sugar solution (beet and cane sugar) were used in this investigation to create honey samples of 20%, 40%, 60% and 80% adulteration concentrations. Honey data extracted from an electronic nose (e-nose) and Fourier Transform Infrared Spectroscopy (FTIR) were gathered, analyzed and compared based on fusion methods. Visual observation of classification plots revealed that the PCA approach able to distinct pure and adulterated honey samples better than the LDA technique. Overall, the validated classification results based on FTIR data (88.0%) gave higher classification accuracy than e-nose data (76.5%) using the LDA technique. Honey classification based on normalized low-level and intermediate-level FTIR and e-nose fusion data scored classification accuracies of 92.2% and 88.7%, respectively using the Stepwise LDA method. The results suggested that pure and adulterated honey samples were better classified using FTIR and e-nose fusion data than single modality data. Full article
(This article belongs to the Section Chemical Sensors)
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Open AccessArticle Temperature and Relative Humidity Estimation and Prediction in the Tobacco Drying Process Using Artificial Neural Networks
Sensors 2012, 12(10), 14004-14021; https://doi.org/10.3390/s121014004
Received: 2 August 2012 / Revised: 28 September 2012 / Accepted: 6 October 2012 / Published: 17 October 2012
Cited by 10 | PDF Full-text (1148 KB) | HTML Full-text | XML Full-text
Abstract
This paper presents a system based on an Artificial Neural Network (ANN) for estimating and predicting environmental variables related to tobacco drying processes. This system has been validated with temperature and relative humidity data obtained from a real tobacco dryer with a Wireless
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This paper presents a system based on an Artificial Neural Network (ANN) for estimating and predicting environmental variables related to tobacco drying processes. This system has been validated with temperature and relative humidity data obtained from a real tobacco dryer with a Wireless Sensor Network (WSN). A fitting ANN was used to estimate temperature and relative humidity in different locations inside the tobacco dryer and to predict them with different time horizons. An error under 2% can be achieved when estimating temperature as a function of temperature and relative humidity in other locations. Moreover, an error around 1.5 times lower than that obtained with an interpolation method can be achieved when predicting the temperature inside the tobacco mass as a function of its present and past values with time horizons over 150 minutes. These results show that the tobacco drying process can be improved taking into account the predicted future value of the monitored variables and the estimated actual value of other variables using a fitting ANN as proposed. Full article
(This article belongs to the Special Issue Sensor-Based Technologies and Processes in Agriculture and Forestry)
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Open AccessArticle Physically-Based Reduced Order Modelling of a Uni-Axial Polysilicon MEMS Accelerometer
Sensors 2012, 12(10), 13985-14003; https://doi.org/10.3390/s121013985
Received: 6 August 2012 / Revised: 20 September 2012 / Accepted: 11 October 2012 / Published: 17 October 2012
Cited by 4 | PDF Full-text (1287 KB) | HTML Full-text | XML Full-text
Abstract
In this paper, the mechanical response of a commercial off-the-shelf, uni-axial polysilicon MEMS accelerometer subject to drops is numerically investigated. To speed up the calculations, a simplified physically-based (beams and plate), two degrees of freedom model of the movable parts of the sensor
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In this paper, the mechanical response of a commercial off-the-shelf, uni-axial polysilicon MEMS accelerometer subject to drops is numerically investigated. To speed up the calculations, a simplified physically-based (beams and plate), two degrees of freedom model of the movable parts of the sensor is adopted. The capability and the accuracy of the model are assessed against three-dimensional finite element simulations, and against outcomes of experiments on instrumented samples. It is shown that the reduced order model provides accurate outcomes as for the system dynamics. To also get rather accurate results in terms of stress fields within regions that are prone to fail upon high-g shocks, a correction factor is proposed by accounting for the local stress amplification induced by re-entrant corners. Full article
(This article belongs to the Special Issue State-of-the-Art Sensors Technology in Italy 2012)
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