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Sensors, Volume 14, Issue 3 (March 2014), Pages 3825-5741

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Open AccessArticle Analyzing Body Movements within the Laban Effort Framework Using a Single Accelerometer
Sensors 2014, 14(3), 5725-5741; https://doi.org/10.3390/s140305725
Received: 28 January 2014 / Revised: 4 March 2014 / Accepted: 6 March 2014 / Published: 21 March 2014
Cited by 9 | PDF Full-text (518 KB) | HTML Full-text | XML Full-text
Abstract
This article presents a study on analyzing body movements by using a single accelerometer sensor. The investigated categories of body movements belong to the Laban Effort Framework: Strong—Light, Free—Bound and Sudden—Sustained. All body movements were represented by a set of activities used for
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This article presents a study on analyzing body movements by using a single accelerometer sensor. The investigated categories of body movements belong to the Laban Effort Framework: Strong—Light, Free—Bound and Sudden—Sustained. All body movements were represented by a set of activities used for data collection. The calculated accuracy of detecting the body movements was based on collecting data from a single wireless tri-axial accelerometer sensor. Ten healthy subjects collected data from three body locations (chest, wrist and thigh) simultaneously in order to analyze the locations comparatively. The data was then processed and analyzed using Machine Learning techniques. The wrist placement was found to be the best single location to record data for detecting Strong—Light body movements using the Random Forest classifier. The wrist placement was also the best location for classifying Bound—Free body movements using the SVM classifier. However, the data collected from the chest placement yielded the best results for detecting Sudden—Sustained body movements using the Random Forest classifier. The study shows that the choice of the accelerometer placement should depend on the targeted type of movement. In addition, the choice of the classifier when processing data should also depend on the chosen location and the target movement. Full article
(This article belongs to the Section Physical Sensors)
Open AccessArticle Fully Distributed Monitoring Architecture Supporting Multiple Trackees and Trackers in Indoor Mobile Asset Management Application
Sensors 2014, 14(3), 5702-5724; https://doi.org/10.3390/s140305702
Received: 17 January 2014 / Revised: 28 February 2014 / Accepted: 18 March 2014 / Published: 21 March 2014
Cited by 10 | PDF Full-text (2023 KB) | HTML Full-text | XML Full-text
Abstract
A tracking service like asset management is essential in a dynamic hospital environment consisting of numerous mobile assets (e.g., wheelchairs or infusion pumps) that are continuously relocated throughout a hospital. The tracking service is accomplished based on the key technologies of an indoor
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A tracking service like asset management is essential in a dynamic hospital environment consisting of numerous mobile assets (e.g., wheelchairs or infusion pumps) that are continuously relocated throughout a hospital. The tracking service is accomplished based on the key technologies of an indoor location-based service (LBS), such as locating and monitoring multiple mobile targets inside a building in real time. An indoor LBS such as a tracking service entails numerous resource lookups being requested concurrently and frequently from several locations, as well as a network infrastructure requiring support for high scalability in indoor environments. A traditional centralized architecture needs to maintain a geographic map of the entire building or complex in its central server, which can cause low scalability and traffic congestion. This paper presents a self-organizing and fully distributed indoor mobile asset management (MAM) platform, and proposes an architecture for multiple trackees (such as mobile assets) and trackers based on the proposed distributed platform in real time. In order to verify the suggested platform, scalability performance according to increases in the number of concurrent lookups was evaluated in a real test bed. Tracking latency and traffic load ratio in the proposed tracking architecture was also evaluated. Full article
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Open AccessArticle Multi-Sensor Fusion for Enhanced Contextual Awareness of Everyday Activities with Ubiquitous Devices
Sensors 2014, 14(3), 5687-5701; https://doi.org/10.3390/s140305687
Received: 26 January 2014 / Revised: 6 March 2014 / Accepted: 7 March 2014 / Published: 21 March 2014
Cited by 20 | PDF Full-text (592 KB) | HTML Full-text | XML Full-text
Abstract
In this paper, the authors investigate the role that smart devices, including smartphones and smartwatches, can play in identifying activities of daily living. A feasibility study involving N = 10 participants was carried out to evaluate the devices’ ability to differentiate between nine
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In this paper, the authors investigate the role that smart devices, including smartphones and smartwatches, can play in identifying activities of daily living. A feasibility study involving N = 10 participants was carried out to evaluate the devices’ ability to differentiate between nine everyday activities. The activities examined include walking, running, cycling, standing, sitting, elevator ascents, elevator descents, stair ascents and stair descents. The authors also evaluated the ability of these devices to differentiate indoors from outdoors, with the aim of enhancing contextual awareness. Data from this study was used to train and test five well known machine learning algorithms: C4.5, CART, Naïve Bayes, Multi-Layer Perceptrons and finally Support Vector Machines. Both single and multi-sensor approaches were examined to better understand the role each sensor in the device can play in unobtrusive activity recognition. The authors found overall results to be promising, with some models correctly classifying up to 100% of all instances. Full article
(This article belongs to the Section Sensor Networks)
Open AccessArticle An Integrated Photoluminescence Sensing Platform Using a Single-Multi-Mode Fiber Coupler-Based Probe
Sensors 2014, 14(3), 5677-5686; https://doi.org/10.3390/s140305677
Received: 6 November 2013 / Revised: 27 February 2014 / Accepted: 6 March 2014 / Published: 21 March 2014
PDF Full-text (499 KB) | HTML Full-text | XML Full-text
Abstract
We demonstrate an integrated fiber optic photoluminescence sensing platform using a novel single-multi-mode fiber coupler (SMFC)-based probe with high collection efficiency for fluorescence signals. The SMFC, prepared using fused biconical taper technology, not only transmits excitation light, but also collects and transmits fluorescence.
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We demonstrate an integrated fiber optic photoluminescence sensing platform using a novel single-multi-mode fiber coupler (SMFC)-based probe with high collection efficiency for fluorescence signals. The SMFC, prepared using fused biconical taper technology, not only transmits excitation light, but also collects and transmits fluorescence. The entire system does not use complex optical components and rarely requires optical alignment. The simple structure of the SMFC considerably improves the light transmission efficiency, signal-to-noise ratio, and sensitivity of the system. Theoretical and experimental results show that the proposed probe increases the collection efficiency by more than eight-fold compared with a bifurcated fiber probe. The performance of the proposed probe was experimentally evaluated by measuring the fluorescence spectra of well-known targets and a fresh Tall Fescue leaf. Full article
(This article belongs to the Special Issue Photonic Sensors for Industrial, Environmental and Health Monitoring)
Open AccessArticle A Caregiver Support Platform within the Scope of an Ambient Assisted Living Ecosystem
Sensors 2014, 14(3), 5654-5676; https://doi.org/10.3390/s140305654
Received: 23 January 2014 / Revised: 13 March 2014 / Accepted: 17 March 2014 / Published: 20 March 2014
Cited by 21 | PDF Full-text (573 KB) | HTML Full-text | XML Full-text
Abstract
The Ambient Assisted Living (AAL) area is in constant evolution, providing new technologies to users and enhancing the level of security and comfort that is ensured by house platforms. The Ambient Assisted Living for All (AAL4ALL) project aims to develop a new AAL
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The Ambient Assisted Living (AAL) area is in constant evolution, providing new technologies to users and enhancing the level of security and comfort that is ensured by house platforms. The Ambient Assisted Living for All (AAL4ALL) project aims to develop a new AAL concept, supported on a unified ecosystem and certification process that enables a heterogeneous environment. The concepts of Intelligent Environments, Ambient Intelligence, and the foundations of the Ambient Assisted Living are all presented in the framework of this project. In this work, we consider a specific platform developed in the scope of AAL4ALL, called UserAccess. The architecture of the platform and its role within the overall AAL4ALL concept, the implementation of the platform, and the available interfaces are presented. In addition, its feasibility is validated through a series of tests. Full article
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Open AccessArticle The Dual Carrier ABSK System Based on a FIR Bandpass Filter
Sensors 2014, 14(3), 5644-5653; https://doi.org/10.3390/s140305644
Received: 8 November 2013 / Revised: 6 March 2014 / Accepted: 7 March 2014 / Published: 20 March 2014
Cited by 4 | PDF Full-text (441 KB) | HTML Full-text | XML Full-text
Abstract
The special impacting filter (SIF) with IIR structure has been used to demodulate ABSK signals. The key points of SIF, including the resonance circuit’s high Q value and the “slope-phase discrimination” character of the filter sideband, are demonstrated in the paper. The FIR
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The special impacting filter (SIF) with IIR structure has been used to demodulate ABSK signals. The key points of SIF, including the resonance circuit’s high Q value and the “slope-phase discrimination” character of the filter sideband, are demonstrated in the paper. The FIR narrow-band bandpass filtering system, which can also provide the impact-filtering effect, is proposed. A dual carrier system of ABSK signals is designed with the proposed FIR filter as its receiver. The simulation results show that the FIR filter can work well. Moreover, compared to the traditional SIF, the proposed FIR filter can not only achieve higher spectral efficiency, but also give better demodulation performance. Full article
(This article belongs to the Section Sensor Networks)
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Open AccessArticle An Analytical Model for the Performance Analysis of Concurrent Transmission in IEEE 802.15.4
Sensors 2014, 14(3), 5622-5643; https://doi.org/10.3390/s140305622
Received: 4 November 2013 / Revised: 12 March 2014 / Accepted: 14 March 2014 / Published: 20 March 2014
Cited by 3 | PDF Full-text (734 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Interference is a serious cause of performance degradation for IEEE802.15.4 devices. The effect of concurrent transmissions in IEEE 802.15.4 has been generally investigated by means of simulation or experimental activities. In this paper, a mathematical framework for the derivation of chip, symbol and
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Interference is a serious cause of performance degradation for IEEE802.15.4 devices. The effect of concurrent transmissions in IEEE 802.15.4 has been generally investigated by means of simulation or experimental activities. In this paper, a mathematical framework for the derivation of chip, symbol and packet error probability of a typical IEEE 802.15.4 receiver in the presence of interference is proposed. Both non-coherent and coherent demodulation schemes are considered by our model under the assumption of the absence of thermal noise. Simulation results are also added to assess the validity of the mathematical framework when the effect of thermal noise cannot be neglected. Numerical results show that the proposed analysis is in agreement with the measurement results on the literature under realistic working conditions. Full article
(This article belongs to the Section Sensor Networks)
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Open AccessArticle Development of an Electrochemical Sensing Technique for Rapid Genotyping of Hepatitis B Virus
Sensors 2014, 14(3), 5611-5621; https://doi.org/10.3390/s140305611
Received: 8 July 2013 / Revised: 22 July 2013 / Accepted: 29 August 2013 / Published: 20 March 2014
Cited by 2 | PDF Full-text (847 KB) | HTML Full-text | XML Full-text
Abstract
Objective: To develop a convenient; sensitive; accurate; and economical technique for genotyping of hepatitis B viruses (HBVs). Methods: The mercapto-modified B1; B2; C1; and C2-specific genotyping probes consisted of two probes for each HBV genotype that served as a double verification
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Objective: To develop a convenient; sensitive; accurate; and economical technique for genotyping of hepatitis B viruses (HBVs). Methods: The mercapto-modified B1; B2; C1; and C2-specific genotyping probes consisted of two probes for each HBV genotype that served as a double verification system. These probes were fixed on the surface of No. 1; 2; 3; and 4 gold electrodes; respectively; via Au-S bonds. Different charge generated by the binding of RuHex to phosphate groups of the DNA backbone before and after hybridization was used for distinguishing the different genotypes. Results: During hybridization with genotype B; the charges detected at the No. 1 and 2 electrodes were significantly increased; while the charge at the No. 3 and 4 electrodes did not change significantly. During hybridization with genotype C; the charges detected at No. 3 and 4 electrodes were significantly increased; while the signals remained unchanged at the No. 1 and 2 electrodes. During hybridization with mixed genotypes (B and C); the charges detected at all four electrodes were significantly increased. The linear range of detection was 10–7 to 10–10 mol/L and the sensitivity for detecting mixed B (10%) or C (10%). Conclusions: Rapid genotyping of HBVs based on electrochemical sensing is simple, has good specificity; and can greatly reduce the cost. This method can be used for sensitive detection of mixed B and C HBV genotypes. Full article
(This article belongs to the Section Biosensors)
Open AccessArticle On the Acoustic Filtering of the Pipe and Sensor in a Buried Plastic Water Pipe and its Effect on Leak Detection: An Experimental Investigation
Sensors 2014, 14(3), 5595-5610; https://doi.org/10.3390/s140305595
Received: 25 November 2013 / Revised: 23 December 2013 / Accepted: 2 January 2014 / Published: 20 March 2014
Cited by 23 | PDF Full-text (486 KB) | HTML Full-text | XML Full-text
Abstract
Acoustic techniques have been used for many years to find and locate leaks in buried water distribution systems. Hydrophones and accelerometers are typically used as sensors. Although geophones could be used as well, they are not generally used for leak detection. A simple
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Acoustic techniques have been used for many years to find and locate leaks in buried water distribution systems. Hydrophones and accelerometers are typically used as sensors. Although geophones could be used as well, they are not generally used for leak detection. A simple acoustic model of the pipe and the sensors has been proposed previously by some of the authors of this paper, and their model was used to explain some of the features observed in measurements. However, simultaneous measurements of a leak using all three sensor-types in controlled conditions for plastic pipes has not been reported to-date and hence they have not yet been compared directly. This paper fills that gap in knowledge. A set of measurements was made on a bespoke buried plastic water distribution pipe test rig to validate the previously reported analytical model. There is qualitative agreement between the experimental results and the model predictions in terms of the differing filtering properties of the pipe-sensor systems. A quality measure for the data is also presented, which is the ratio of the bandwidth over which the analysis is carried out divided by the centre frequency of this bandwidth. Based on this metric, the accelerometer was found to be the best sensor to use for the test rig described in this paper. However, for a system in which the distance between the sensors is large or the attenuation factor of the system is high, then it would be advantageous to use hydrophones, even though they are invasive sensors. Full article
(This article belongs to the Special Issue Sensors for Fluid Leak Detection) Printed Edition available
Open AccessArticle Improving Data Quality with an Accumulated Reputation Model in Participatory Sensing Systems
Sensors 2014, 14(3), 5573-5594; https://doi.org/10.3390/s140305573
Received: 13 December 2013 / Revised: 20 January 2014 / Accepted: 10 March 2014 / Published: 20 March 2014
Cited by 7 | PDF Full-text (666 KB) | HTML Full-text | XML Full-text
Abstract
The ubiquity of mobile devices brings forth a sensing paradigm, participatory sensing, to collect and interpret sensory information from the environment. Participants join in multifarious sensing tasks and share their data. The sensing result can be obtained in light of shared data. It
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The ubiquity of mobile devices brings forth a sensing paradigm, participatory sensing, to collect and interpret sensory information from the environment. Participants join in multifarious sensing tasks and share their data. The sensing result can be obtained in light of shared data. It is not uncommon that some corrupted data is provided by participants, which makes sensing result unreliable accordingly. To address this nontrivial issue, we proposed the accumulated reputation model (ARM) to improve the accuracy of the sensing result. In ARM, participants’ reputation will be computed and accumulated based on their sensing data. The sensing data from reputable participants make higher contributions to the sensing result. ARM performs well on calculating accurate sensing results, even in extreme scenarios, where there are many inexperienced or malicious participants. Full article
(This article belongs to the Section Sensor Networks)
Open AccessArticle Estimates of Minor Ocean Tide Loading Displacement and Its Impact on Continuous GPS Coordinate Time Series
Sensors 2014, 14(3), 5552-5572; https://doi.org/10.3390/s140305552
Received: 7 January 2014 / Revised: 13 February 2014 / Accepted: 18 February 2014 / Published: 20 March 2014
Cited by 4 | PDF Full-text (4456 KB) | HTML Full-text | XML Full-text
Abstract
The site displacement due to ocean tidal loading is regarded as one of the largest uncertainties in precise geodetic positioning measurements, among which the effect of minor ocean tides (MOT), except for the 11 main tidal constituents, are sometimes neglected in routine precise
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The site displacement due to ocean tidal loading is regarded as one of the largest uncertainties in precise geodetic positioning measurements, among which the effect of minor ocean tides (MOT), except for the 11 main tidal constituents, are sometimes neglected in routine precise global positioning system (GPS) data processing. We find that MOT can cause large vertical loading displacements with peak-to-peak variations reaching more than 8 mm at coastal/island stations. The impact of MOT on the 24-hour GPS solution is slightly larger than the magnitude of MOT loading itself, with peak-to-peak displacement variation at about 10 mm for the horizontal and 30 mm for the vertical components. We also find that the vertical velocity of all the selected stations in the Southwest Pacific was reduced by more than 10% after considering the MOT effect, while stations with weighted root mean square reduced data account for 62%, 59%, and 36% for the up, east, and north components respectively, in particular for most coastal/island stations. Furthermore, MOT correction could significantly reduce the annual signal of the global stacked east component, the near fortnightly and the long-term periodic signals in the up component. The power of some anomalous harmonics of 1.04 cycle per year is also decreased to some extent. These results further proved the benefits of MOT correction in precise GPS data processing. Full article
(This article belongs to the Section Remote Sensors)
Open AccessArticle Adaptive Preheating Duration Control for Low-Power Ambient Air Quality Sensor Networks
Sensors 2014, 14(3), 5536-5551; https://doi.org/10.3390/s140305536
Received: 15 January 2014 / Revised: 8 March 2014 / Accepted: 9 March 2014 / Published: 20 March 2014
PDF Full-text (639 KB) | HTML Full-text | XML Full-text
Abstract
Ceramic gas sensors used for measuring ambient air quality have features suitable for practical applications such as healthcare and air quality management, but have a major drawback—large power consumption to preheat the sensor for accurate measurements. In this paper; the adaptive preheating duration
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Ceramic gas sensors used for measuring ambient air quality have features suitable for practical applications such as healthcare and air quality management, but have a major drawback—large power consumption to preheat the sensor for accurate measurements. In this paper; the adaptive preheating duration control (APC) method is proposed to reduce the power consumption of ambient air quality sensor networks. APC reduces the duration of unnecessary preheating, thereby alleviating power consumption. Furthermore, the APC can allow systems to meet user requirements such as accuracy and periodicity factor when detecting the concentration of a target gas. A performance evaluation of the power consumption of gas sensors is conducted with various user requirements and factors that affect the preheating duration of the gas sensor. This shows that the power consumption of the APC is lower than that of continuous power supply methods and constant power supply/cutoff methods. Full article
Open AccessArticle Samba: A Real-Time Motion Capture System Using Wireless Camera Sensor Networks
Sensors 2014, 14(3), 5516-5535; https://doi.org/10.3390/s140305516
Received: 14 January 2014 / Revised: 12 March 2014 / Accepted: 12 March 2014 / Published: 20 March 2014
Cited by 4 | PDF Full-text (9250 KB) | HTML Full-text | XML Full-text
Abstract
There is a growing interest in 3D content following the recent developments in 3D movies, 3D TVs and 3D smartphones. However, 3D content creation is still dominated by professionals, due to the high cost of 3D motion capture instruments. The availability of a
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There is a growing interest in 3D content following the recent developments in 3D movies, 3D TVs and 3D smartphones. However, 3D content creation is still dominated by professionals, due to the high cost of 3D motion capture instruments. The availability of a low-cost motion capture system will promote 3D content generation by general users and accelerate the growth of the 3D market. In this paper, we describe the design and implementation of a real-time motion capture system based on a portable low-cost wireless camera sensor network. The proposed system performs motion capture based on the data-driven 3D human pose reconstruction method to reduce the computation time and to improve the 3D reconstruction accuracy. The system can reconstruct accurate 3D full-body poses at 16 frames per second using only eight markers on the subject’s body. The performance of the motion capture system is evaluated extensively in experiments. Full article
(This article belongs to the Section Sensor Networks)
Open AccessArticle Analytical Calculation of Sensing Parameters on Carbon Nanotube Based Gas Sensors
Sensors 2014, 14(3), 5502-5515; https://doi.org/10.3390/s140305502
Received: 8 January 2014 / Revised: 19 February 2014 / Accepted: 5 March 2014 / Published: 20 March 2014
Cited by 16 | PDF Full-text (775 KB) | HTML Full-text | XML Full-text
Abstract
Carbon Nanotubes (CNTs) are generally nano-scale tubes comprising a network of carbon atoms in a cylindrical setting that compared with silicon counterparts present outstanding characteristics such as high mechanical strength, high sensing capability and large surface-to-volume ratio. These characteristics, in addition to the
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Carbon Nanotubes (CNTs) are generally nano-scale tubes comprising a network of carbon atoms in a cylindrical setting that compared with silicon counterparts present outstanding characteristics such as high mechanical strength, high sensing capability and large surface-to-volume ratio. These characteristics, in addition to the fact that CNTs experience changes in their electrical conductance when exposed to different gases, make them appropriate candidates for use in sensing/measuring applications such as gas detection devices. In this research, a model for a Field Effect Transistor (FET)-based structure has been developed as a platform for a gas detection sensor in which the CNT conductance change resulting from the chemical reaction between NH3 and CNT has been employed to model the sensing mechanism with proposed sensing parameters. The research implements the same FET-based structure as in the work of Peng et al. on nanotube-based NH3 gas detection. With respect to this conductance change, the I–V characteristic of the CNT is investigated. Finally, a comparative study shows satisfactory agreement between the proposed model and the experimental data from the mentioned research. Full article
(This article belongs to the Section Chemical Sensors)
Open AccessArticle Improved Algorithms for the Classification of Rough Rice Using a Bionic Electronic Nose Based on PCA and the Wilks Distribution
Sensors 2014, 14(3), 5486-5501; https://doi.org/10.3390/s140305486
Received: 11 January 2014 / Revised: 22 February 2014 / Accepted: 11 March 2014 / Published: 19 March 2014
Cited by 10 | PDF Full-text (880 KB) | HTML Full-text | XML Full-text
Abstract
Principal Component Analysis (PCA) is one of the main methods used for electronic nose pattern recognition. However, poor classification performance is common in classification and recognition when using regular PCA. This paper aims to improve the classification performance of regular PCA based on
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Principal Component Analysis (PCA) is one of the main methods used for electronic nose pattern recognition. However, poor classification performance is common in classification and recognition when using regular PCA. This paper aims to improve the classification performance of regular PCA based on the existing Wilks ?-statistic (i.e., combined PCA with the Wilks distribution). The improved algorithms, which combine regular PCA with the Wilks ?-statistic, were developed after analysing the functionality and defects of PCA. Verification tests were conducted using a PEN3 electronic nose. The collected samples consisted of the volatiles of six varieties of rough rice (Zhongxiang1, Xiangwan13, Yaopingxiang, WufengyouT025, Pin 36, and Youyou122), grown in same area and season. The first two principal components used as analysis vectors cannot perform the rough rice varieties classification task based on a regular PCA. Using the improved algorithms, which combine the regular PCA with the Wilks ?-statistic, many different principal components were selected as analysis vectors. The set of data points of the Mahalanobis distance between each of the varieties of rough rice was selected to estimate the performance of the classification. The result illustrates that the rough rice varieties classification task is achieved well using the improved algorithm. A Probabilistic Neural Networks (PNN) was also established to test the effectiveness of the improved algorithms. The first two principal components (namely PC1 and PC2) and the first and fifth principal component (namely PC1 and PC5) were selected as the inputs of PNN for the classification of the six rough rice varieties. The results indicate that the classification accuracy based on the improved algorithm was improved by 6.67% compared to the results of the regular method. These results prove the effectiveness of using the Wilks ?-statistic to improve the classification accuracy of the regular PCA approach. The results also indicate that the electronic nose provides a non-destructive and rapid classification method for rough rice. Full article
(This article belongs to the Special Issue Gas Sensors - 2013)
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